BRITISH
MINING
A TREATISE
ON THE
METALLIFEROUS
MINES
OF
THE UNITED KINGDOM
B 407319
DUPL
ROBERT HUNT, F.R.S.
TN
57
HO4
Capio Lumen
CROSBY LOCKWOOD & CO.
LONDON
•
i
ARTES
LIBRARY
1837
SCIENTIA
VERITAS
OF THE
UNIVERSITY OF MICHIGAN |
E-PLURIBUS UNUM
TUE BUR
!
SI QUAERIS PENINSULAM AMOENAM
CIRCUMSPICE
BRITISH MINING
30121
BRITISH MINING
A TREATISE
ON THE
HISTORY, DISCOVERY, PRACTICAL DEVELOPMENT
AND FUTURE PROSPECTS
OF
METALLIFEROUS MINES
IN THE
UNITED KINGDOM
BY ROBERT HUNT, F.R.S.
=
THE KEEPER OF MINING RECORDS
FORMERLY SECRETARY OF THE ROYAL CORNWALL POLYTECHNIC SOCIETY
AND PROFESSOR OF EXPERIMENTAL SCIENCE IN THE ROYAL SCHOOL OF MINES
EDITOR OF URE'S DICTIONARY OF ARTS, MANUFACTURES, AND MINES
ETC. ETC. ETC.
With upwards of Two Hundred and Thirty Illustrations
of
Capio Lume
CROSBY
LONDON
LOCKWOOD AND CO.
7, STATIONERS' HALL COURT, LUDGATE HILL
1884
[All rights reserved]
LONDON:
PRINTED BY J. S. VIRTUE AND CO., LIMITED,
CITY ROAD,
лвие ев-9-1
PREFACE.
THE Mineral resources of the United Kingdom have been far in advance of
those of any country in the world. The annual value of the Metalliferous
Ores and Earthy Minerals raised has approached to eighty million pounds
sterling, the result of the difficult and dangerous labours. of more than fifty
thousand miners, directed by a large staff of educated engineers and
experienced agents.
For two thousand years diligent explorations have been made, and our
mining fields have supplied all our metallurgical industries with the native
material required for their smelting operations. The drain upon our mineral
veins has been constant and excessive. It has been repeatedly urged that
the rate at which this exhaustion has been progressing has not received the
attention which it deserves. Indeed, there has not hitherto been any
comprehensive examination of the subject.
It is true that a Royal Commission was appointed in 1866 "to inquire as
to the quantity of Coal consumed in various branches of manufacture,"
and to determine the probable duration of our fossil fuel. The author, as a
member of the Commission, on whom devolved the labours of the statistical
division of that inquiry, was brought constantly in contact with our great
metallurgists, and they pressed on him the necessity of obtaining, if possible,
a solution of this problem in relation to Metal mines, and of inquiring how
far the applications of science would facilitate the extraction of minerals,
which they regarded as of equal importance with the Coal inquiry.
This led eventually to the collection of the materials which are now placed,
it is hoped in a satisfactory manner, before the readers of this volume.
An attempt has been made to estimate the rate at which our mineral
veins have been undergoing the process of exhaustion; to furnish detailed
vi
PREFACE.
information on all points connected with Mining and Mineral Statistics
during the present century; and, from the careful consideration of all the
improvements which have been introduced for economising the cost of
production, in exploring our mines, and preparing the minerals for the
market, to deduce information which may guide the miners of the future.
These important subjects naturally divide themselves into the following
heads, which have been separately and carefully treated in these pages :-
I. HISTORICAL SKETCH: embracing a consideration of the progress of
mining from the period when Celtic Britain passed unto the rule of the
Roman Empire, to the time when Queen Elizabeth sought to improve our
mining operations by the introduction of German miners, and then, follow-
ing the inquiry to the close of the eighteenth century, when James Watt
and other engineers restored the declining prospects of our mines by the
introduction of steam power for draining their depths.
II. THE FORMATION OF MINERAL DEPOSITS: being an examination of
the characteristics of the métal-bearing rocks, and an elucidation of the
hypotheses which have been promulgated to explain the phenomena of the
formation of metalliferous veins. These interesting and important matters
are treated in such a manner as will, it is hoped, serve to convince the miner
that Nature has fixed laws in regulating her subterranean operations, and
to introduce a few of the certainties of science into an arena of debate in
which uncertainty prevails.
III. PRACTICAL MINING: dealing with the discovery of mineral lodes,
the operation of opening mines, the extraction of the metalliferous ores and
their preparation for the smelter. The ventilation of levels, the value of new
explosives for the blasting of rocks, the draining of mines, and the
means employed to relieve the miners from the toil of climbing and its
injurious effects, have been each considered.
IV. THE FUTURE PROSPECTS OF BRITISH MINING, in which is examined
respectively, the rate at which exhaustion has proceeded, the limits of an
hypothetical metalliferous zone, the depths to which ores may be expected
to be found, and the probabilities of our opening new mineral districts. A
discussion of the improvements which will be introduced in mining, followed
by general conclusions drawn from an examination of the whole subject,
concludes the volume.
Although in his official capacity the Author is well known to the miners
and metallurgists of the United Kingdom, it has been suggested that a brief
statement is necessary to explain to the general public the nature of the
PREFACE.
vii
training which has prepared him for the responsible task which he has
undertaken. For several years, as the Secretary of the Royal Cornwall
Polytechnic Society, he made experiments on the electrical phenomena
detected in mineral veins, examined chemically the water of the mines,
and carried out physical inquiries connected with the economy of the
steam pumping-engines. Beyond these, he endeavoured to induce the young
miners to study the technical application of science to their own industry,
which led eventually, in 1859, to the establishment, under the title of "The
Miners' Association of Cornwall and Devonshire," of a system of giving
instruction to the young miners near the districts in which they laboured.
This Association is still, in 1884, pursuing its useful labours.
In 1845 the Author was appointed by the Government THE KEEPER OF
MINING RECORDS, which office he filled for thirty-seven years, organizing
a system of collecting returns of our mineral produce upon a perfectly
voluntary system. This was so successful as to receive the most cordial
co-operation of our mine owners, engineers and agents, and the proprietors
of our great metallurgical works, by the aid of which was produced annually
the "Mineral Statistics of the United Kingdom."
Intimately connected with our mines, visiting annually a considerable
number of them, the Author has had the advantage of the utmost degree of
friendly attention from our miners. To the mine agents in every division
of these islands he is deeply indebted for information of a practical character
which could not otherwise have been obtained. Miners, metallurgists,
manufacturers, railway officials, and others, have most freely furnished much
special information.
There are many personal friends who, by giving the assistance of
their practical knowledge, have rendered these pages more complete than
they could otherwise have been. The Author would have desired to give
the names of some especially who have contributed those results of long
experience which have added to the completeness of this work; but, fearing
that a selection could not be made without incurring the risk of giving offence,
he has thought it advisable to confine himself to a general acknowledg-
ment of his appreciation of the great assistance which they have rendered,
and to solicit their acceptance of this general expression of sincere thanks.
Besides these personal sources of information, in the construction of this
volume every publication which can be regarded as an authority has been
carefully studied: much information of real value from which has been
transferred to its pages, and always carefully acknowledged.
viii
PREFACE.
The Author, in conclusion, feels bound, in committing his labours to the
unprejudiced attention of all who are interested in the subject, to express
his conviction that, notwithstanding the vast quantity of mineral raised from
our mines during the long period they have been worked, there still
remain undisturbed, within the limits which have been assigned to the
Metalliferous Zone, metallic ores in sufficient quantities to ensure a profit-
able return for many generations to come, if capital is honestly and care-
fully employed, under the judicious direction of science and experience.
CONTENTS.
BOOK I.
HISTORICAL SKETCH OF BRITISH MINING.
CHAPTER I.
MINING PREVIOUS TO THE ROMAN INVASION.
Ancient Mining for Tin-Phoenicians discover Britain-Trade in Tin from Cornwall
-The Isles of the Cassiterides-Submergence of Land-Detrital Deposits-
Stanniferous Regions of Cornwall-Ancient Smelting Works-Jews' Houses-
Early Lead and Copper Mining-Gold in Britain
CHAPTER II.
MINING DURING THE ROMAN OCCUPATION.
Roman Mining in Wales, in Shropshire, Derbyshire, Cornwall, &c.-Ancient Mining
Tools-Lead Mines in the Mendips-Roman Pigs of Lead-Roman Copper
Mines-Ancient Metallurgy of Copper-Gold Mines in Wales worked by the
Romans-Roman Iron Mines in various Places
CHAPTER III.
MINING TO THE EIGHTEENTH CENTURY.
The Saxons in Cornwall-The Use of Tin in Bells-Bronze-Brass and Latten
Ware-William the Conqueror creates an Earl of Cornwall-Mining for Tin in
the Reign of John-Jews the principal Miners-Charters granted to the Tinners
-The Stannary Court and Parliament-Tin Bounding-The Bailiff of Black-
more-Stannary Laws-Improvement of the Tin Trade-Tin Factors-The
Cornish Tinners-The Discovery of Tin Lodes-The Introduction of Gun-
powder for Blasting-Streaming for Tin-Blowing Houses-Section of Tin
Deposits-Prices of Tin to 1799-Mines worked in and under the Sea-
Letter on the Tin Trade
PAGE
I
21
45
CHAPTER IV.
MINING FOR TIN AND COPPER TO THE END OF THE
EIGHTEENTH CENTURY.
Leases granted-German Miners introduced by Queen Elizabeth-Mining in the
Eighteenth Century-The Draining of Mines-Steam Engines first introduced
-Early Mining for Copper-Copper Mines in Cumberland-Letters Patent
X
CONTENTS.
PAGE
granted to German Miners-The Divining Rod (Virgula Divinatoria) intro-
duced-The Practice of using the Divining Rod-Sale of Copper Ore by
"Ticketings”—Copper Smelting-Letter on Copper Trade, 1785-Working
Mines on Tribute-Copper Ore Account-Savery's Steam Engine-Newcomen
—Trevithick, Watt, &c.-Copper Mines in Staffordshire, Wales, Scotland, &c.. 83
CHAPTER V.
MINING FOR LEAD, SILVER, ETC., TO THE END OF THE
EIGHTEENTH CENTURY.
Mines Royal-Mineral and Battery Works-Laws relating to these Societies-
Combe Martin Lead Mines-Lead and Zinc Mines-Calamine smelted at Bristol
—Mendip Lead Mines-Ancient Charter-Laws of the Mendips-Caverns in the
Limestone-Liberties and Customs of Lead Miners in Derbyshire-Working of
Derbyshire Mines-Old Methods of getting Lead Ore-Selling and Smelting
Lead Ore-Mining Lease-Mining in Wales, Cumberland, Lancashire, &c.-
The Company of Mine Adventurers-Silver Mines in Scotland—The Master
of Metals in Scotland
•
125
CHAPTER VI.
GOLD, PLUMBAGO, IRON ORE, AND SUNDRIES, TO THE END
OF THE EIGHTEENTH CENTURY.
Gold in the Tin Streams of Cornwall-Gold in Wales, Scotland, and Ireland—
Produce of Gold in the United Kingdom-Iron Ore worked by the Romans-
Bloomeries in High Furness, &c.-Lord Dudley's Patent-Sussex Iron Works
-Plumbago of Borrowdale-Manganese in Devonshire, Warwickshire, &c.—
Antimony-Cobalt-Bismuth-Uranium, &c. .
. 167
BOOK II.
ON THE FORMATION OF METALLIFEROUS DEPOSITS.
CHAPTER I.
THE ROCKS OF MINING DISTRICTS AND THE DISTRIBUTION OF
METALLIFEROUS DEPOSITS.
Distribution of Mines-Metalliferous Character of Rocks-Granite and Greenstone
-Killas or Clay Slate-Structure of Granite-Influence of Rocks on Mineral
Deposits-Colour of Rock Formations-Influence of Rocks on Deposits-
Directions of Lodes-Ancient Sea Coast-Elvan Courses-Their Influence on
Lodes-Characteristics of Elvan-Relation of Elvan Courses to Lodes-
Greenstone Rock and Lodes-Definition of Killas or Clay Slate-Serpentine
and Diallage Rocks-The Formation of Rock Masses-Alterations in Rocks-
CONTENTS.
Lamination of Clay-Divisional Planes in Rocks-Chemical Composition of
Rocks-Granites of Dartmoor-Copper Ore in Somersetshire-Gravel Deposits
Limestones-Toadstones-Basaltic Rocks-Slickensides-Lead Ore in Alston ·
Moor, Cumberland, Cardiganshire, Flintshire, Cheshire, &c.-Alderley Edge
Lead and Copper Beds-Isle of Man, Anglesea, Scotland, Ireland.
•
xi
PAGE
189
CHAPTER II.
MECHANICS OF MINERAL LODES, FAULTS, CROSS COURSES, ETC.
Veins of various Characters-True Lodes or Mineral Veins-Definition of Terms
relating to Lodes-Description of Lodes-Mechanics of dislocations-Heaves
and Slides of Lodes-Stratigraphical Systems-Symmetrical System in Rocks—
Crystalline Forces-Enlargement of Veins-Length of Mineral Lodes-Direc-
tion and Dip-Breadth of Mineral Lodes-Yorkshire and Cumberland Lead
Mines-Alston Moor Mines-Great Sulphur Veins-The Cross Veins of Alston
-The Lake District, Keswick, &c.-Wales: Lodes in Cardiganshire, Flintshire,
Anglesea, Isle of Man, &c.
• 283
CHAPTER III.
DEPOSITS.
THE LAWS RELATING TO MINERAL
Hypotheses by Rosler, Stahl, Hoffman, Zimmermann, Von Oppel, Werner, Lehmann,
Wallerius, Delius, Bergmann, Cotta, Fournet, Necker-New Theory of the
Formation of Veins-Definitions-Hypotheses Examined-Influence of Unstra-
tified Rocks-Robert Were Fox on Mineral Veins-Operation of Osmose Force
-Wallace's Hypothesis-Influence of Aqueous Agency-Contemporaneous
Formation-Segregation-Small Veins in Clay-Slate-Lateral Infiltration-
Sublimation-Injection-Remarkable Tin Veins-Stanniferous Granite-Section.
of Happy Union Tin Mine-Bullen Garden Mine-Copper Pyrites in Granite—
Dissemination of Metallic Ores-Diffusion of Zinc Ores-Analyses of Mine
Water-The Filling of Fissures-Deposits from Hot Springs-Heat of Lodes
and Subterranean Waters-Temperature of Rocks-Electrical Experiments in
Relation to Lode Formation-Summary
· 327
CHAPTER IV.
REMARKABLE PHENOMENA OBSERVED IN METALLIFEROUS
ORE DEPOSITS.
Coffens, or Open Workings-Characters of Mineral Districts-Mineral Lodes in St.
Just-Botallack worked under the Sea-St. Ives Mining District-The Carbona
in St. Ives Consols-Flat Lode of Carn Brea-Stanniferous Deposits-Helston
Mining Districts-Great Wheal Vor Tin Mine-Carclaze Mine, St. Austell,
Rosewarne and Relistian Mines -- Fragments of Rock enclosed in veins
Organic Remains in Lodes-Great Gwennap Adit-United and Consolidated
Mines Hot Level United Mines-Herodsfoot Mine-Wheal Mary Ann-
Dolcoath Productive Parts of Lodes-The Minera Mines-Parys Mountain and
Mona Mine-Turf Copper Mine-Great Ormes Head-Lodes in the Lower
Limestone Rodderup Fell Mine-Allendale and Weardale Mines-Irish Mines
-Gold at Croghan Kinshela-Comby and Crystalline Lodes-Fluor Spar-
Barytes Mines-General Résumé-Pseudomorphism and Metamorphism, &c. 397
xii
CONTENTS.
BOOK III.
PRACTICAL MINING.
CHAPTER I.
PAGE
DISCOVERY OF MINERAL LODES AND THE OPENING OF MINES.
Search for Lodes-Shodes and Bryle of a Lode-Search for Lead Lodes by Hushing—
Hand Boring, &c. .
499
CHAPTER II.
PRACTICAL OPERATIONS FOR THE EXTRACTION OF METALLI-
FEROUS ORES.
·
Rock-boring Machinery-Compressed Air-Boring Engines and Compressors-The
Colladon Compressor-Three-Cylinder Compressor-Dry Compressors-
Receivers and Air Pipes-Railways in Mine Headings-Stands and Frames
for Boring Machines-Severn Tunnel Borer-Darlington Rock Drill-Boring
Tools and Drills-Explosives for Blasting-Nitro-Glycerine, &c.—Electrical
Blasting Firing-Cables and Conducting-Wires-Economy of Boring Machines
-Systems of Boring-Charging and Blasting-Pneumatic Engines-Rate of
Work-Plant of Rock-boring Machinery-Chronological Table-Subterranean
Working-Borlase and Pryce on Mining-Sinking Shafts-Timbering and
Walling Shafts, Galleries, &c.-Partnership Bargains in Alston-The Kind-
Chaudron System-Triger's System of Sinking Shafts-Horse Whims-Accidents
-Skips travelling in Shafts-Waggons-Loading-Underground Stoping.
CHAPTER III.
507
VENTILATION OF MINES-DRAINAGE OF MINES, ETC.
Natural and Artificial Ventilation-Temperature of Mines-Ventilating Machines-
Mechanical Ventilators-Anemometers-Effectiveness of Explosions-Drainage
by Adits-Average Annual Rainfall-Water pumped from Mines-Duty of
Pumping Engines-Steam Engines-Valves-Hydraulics-Transfer of Power-
The Cornish Pumping Engines-Improvement in Pumping Engines-Experi-
ments on Cornish Boilers-The Cornish System of Stoking-Husband's Safety
Governor-The Man Engine-Wedge for Blasting-Tools-Mine Surveying-
Variation of the Needle-Surveying Level-Theodolite-The Transit Instru-
ments-Dialling with and without the Compass-Needle-Dislocation of Lodes-
Rules for tracing Faults-Hoefer's Mode for indicating Faults-Movements pro-
ducing Fissures-Dislocated Lodes-Commercial Notes-Sampling and Sales of
Ore-Standard Returning Charges-Estimation of Value .
607
CHAPTER IV.
DRESSING METALLIFEROUS ORES-PREPARATION FOR SMELTER.
Old Methods of Dressing--Copper Ore Dressing Machinery-Dynamical Metallurgy
-Continuous Jigging Machinery-The Transport of Ores-Specific Gravity of
, Minerals-Physical Treatment of Ores-Enriching of Vein Stuff-Volumetric
Sizing of Minerals-Division of Ores for Dressing-Machinery and Apparatus-
Washing of Vein Stuff-Sizing Trommels-Stone Breakers and Grinders-
Crushing Machinery-Stamps-Pulverising Slimes-Perforations in Plates-
Separating Cylinders and Troughs-Jigging Machinery-Buddling Apparatus-
Frames-Calcining Apparatus-Chemical Processes-Extracting Copper from
Pyrites-Sampling Tin, Copper, and Lead Ores-Dressing Floors
•
687
CONTENTS.
xiii
PAGE
CHAPTER V.
DISCOVERY AND EXTRACTION OF IRON ORES FROM VEINS
AND OTHER DEPOSITS.
Iron Ores of the United Kingdom-Geological Occurrence-Spathose Ore-Silver
in Iron Lodes-Lancashire and Cumberland Iron Ores-Hæmatite Iron Ores
-Aluminous Ores of Antrim-Bauxite-Production of our Iron Mines
•
• 793
BOOK IV.
THE FUTURE PROSPECTS OF BRITISH MINING.
CHAPTER I.
SUMMARY.—EXAMINATION OF THE PROBABLE EXHAUSTION OF
METALLIFEROUS MINERALS.
Mining Record Office-Early Trade in Tin-East India and Dutch Trade-Total
Quantity of Tin exhausted-Early Production of Copper-Progress of Copper
Trade Colonial and Foreign Copper-Estimate of Copper exhausted-
Produce of Lead and Silver-Zinc Ores-Manufacture of Brass and Bronze-
Production of Zinc and Miscellaneous Minerals-Total Production of the
United Kingdom
813
CHAPTER II.
ON THE LIMITS OF THE METALLIFEROUS ZONE.
Geological Condition-Rocks favourable to Mineral formation-Lodes in Primary
Rocks-Conditions under which Lodes occur-Evidence in favour of a defined
Metalliferous Zone.
• 851
CHAPTER III.
THE OCCURRENCE OF ORES AT GREAT DEPTHS, OR IN NEW
DISTRICTS.
The Extent of our present knowledge-Improvement in Mining, in Dressing Ores,
&c.-Unexplored Mining Districts
859
CHAPTER IV.
IMPROVEMENTS AND ECONOMY IN WORKING BRITISH MINES.
Suggestions from Practical Miners-Increased Economy--Improved Ventilation-
Borings and actual results as to Capital and Profits-Suggestion relative to
Science-teaching-Mining School and Classes-The Miners' Association-
Remarks on Mining Adventure
863
xiv
CONTENTS.
PAGE
CHAPTER V.
GENERAL SUMMARY AND CONCLUSION.
The Quantity of Ores of the Metals probably obtainable-The necessity for consider-
able improvements in Mining, for attention to the health of Miners, for economy
in Machines for Ventilation-Breaking Ground, &c.-The advantages to be
derived from a less speculative system of Mine Adventure
APPENDIX.
879
Specific Gravity of Metals, Precious and Common Ores-Table showing Underlie
and Perpendicular of Lodes for Surveyors-Annual Produce of the Tin of Corn-
wall from 1750 to 1817-Annual Produce of the Tin of Cornwall from 1818 to
1837-General Statement of Tin Trade of Cornwall from 1750 to 1799-Annual
Produce of the Tin of Cornwall and Devon since 1848-Average Price per ton
of Tin Ore and Tin from 1854 to 1882-Tin shipped from Cornwall for China by
the East India Company-Quantity of Tin Exported from 1788 to 1791, show-
ing Countries-Tin supplied to East India Company from Cornwall under Stock-
ing System-Production of Copper Ore in Cornwall from 1726 to 1775-Annual
Produce of Copper in Cornwall from 1727 to 1771-Annual Produce of Copper
sold at Ticketings from 1772 to 1799-Annual Sales of Copper Ore at Cornish
Ticketings from 1800 to 1881-Copper Sales (British, Foreign, and Colonial) at
Swansea from 1804 to 1863-Copper Sales (British, Foreign, and Colonial) at
Swansea from 1861 to 1881-Table of Consolidated Mines (Gwennap) Produce
from 1819 to 1836-Private Contract Purchases from 1832 to 1862-Average
price of Copper Ore and Copper since 1855-Table of Cost at Fowey Consols
Mine in 1837-Copper Produce, Mona Mine, Anglesea, from 1855 to 1882-
Copper Produce, Parys Mountain Mine, Anglesea, from 1855 to 1882-Fine
Copper from Mona and Parys Mountain Mines from 1820 to 1835-Lead Ore,
Lead, and Silver, obtained from 1848 to 1871-Lead Ore, Lead, and Silver,
obtained from Cornwall from 1845 to 1882-Lead Ore, Lead, and Silver, obtained
from Durham and Northumberland since 1845-Greenwich Hospital Duty Lead
Ore from 1768 to 1881--Lead Ore, Lead, and Silver from Allendale and Wear-
dale from 1845 to 1881-Lead Ore, Lead, and Silver from Cardiganshire from
1845 to 1882—Lead Ore, Lead, and Silver from the Isle of Man from 1845 to
1882-Lead Ore, Lead, and Silver from Scotland from 1845 to 1882-Lead Ore,
Lead, and Silver from Ireland from 1845 to 1882-Prices of Lead at Grassington
from 1780 to 1843-Prices of English Lead per Fodder from 1783 to 1828-
Zinc Ore raised in United Kingdom from 1856 to 1882-Prices of Zinc Ore and
Metallic Zinc from 1858 to 1881-Imports and Exports of Zinc from 1823 to
1858-Manganese, Produce of, from 1872 to 1881. .
885
•
GLOSSARY OF TERMS EMPLOYED IN, OR RELATING TO, METALLIFEROUS MINING • 907
LIST OF ILLUSTRATIONS.
NO.
PAGE
I.
4.
2.
3.
""
THE "BRIDGE IN PLYMOUTH SOUND
BRONZE IMAGE FOUND IN ST. JUST
CHYSOISTER HUT-A Cave Dwelling
ROMAN SPADES
.
5. ANCIENT OAK SHOVELS
12
15
24
30
30
6.
LAMB BOTTOM CAVERN ON THE MENDIPS
31
7.
ROMAN SLAB OF COPPER
38
8. ROMAN PICK
40
9.
PLAN OF NORTH DOWNS TIN-BOUNDS
53
IO.
II.
THE DIVINING ROD .
13.
12.
USING THE DIVINING ROD-FROM AGRICOLA
SECTION OF ECTON COPPER MINE
SECTION OF CLAYTON COPPER MINE
14. GRANITE TOR ON ROSEWALL HILL
15.
HYPOTHETICAL SECTION OF GRANITE ROCKS
16. CLAY PIT AT ST. Agnes
17.
18.
•
OLD SEA-COAST AT ST. Agnes
GRANITE VEINS AT ST. MICHAEL'S MOUNT
19. GRANITE VEINS AT TREWAVAS CLIFF
96
97
117
118
196
197
204
205
206
206
20.
SECTION OF ELVAN COURSES AND COPPER LODES
21.
ELVAN COURSES AND MINERAL LODES NEAR REDRUTH
22.
207
208
26.
27.
32.
SECTION OF ELF HILLS QUARRY
ELVAN COURSE OBLITERATING Lodes
23. GREENSTONE ROCKS FROM HAYLE, THROUGH GWINNEAR
24. SECTION OF STRATA AT ST. AGNES
25. CARN Brea District
LAMINATION OF CLAY BY ELECTRICITY
TOADSTONE IN MILL CLOSE MINE, DERBYSHIRE
28. SECTION OF LIMESTONE AND TOADSTONE, GREAT HUCKLOW
29. SECTION OF DISLOCATED ROCKS
30. SECTIONS OF CARBONiferous LimeSTONE
31. SECTION OF WHIN SILL, NEAR GREAT BAVINGTON
33. CLIFF OF CONGLOMERATE, at Alderley Edge
34. LEADHILLS AND WANLOCK HEAD DISTRICT
35. A FISSURE VEIN
2II
•
213
216
•
216
223
237
242
245
•
251
252
252
257
269
286
xvi
LIST OF ILLUSTRATIONS.
NO.
36. HEAVES AT SEALHOLE MINE, ST. AGNES
PAGE
37. DISLOCATIONS IN PENHALLS MINE, DITTO
38. PART OF GREAT CROSS COURSE (REDRUTH)
293
294
39. DISLOCATION OF LODES IN A PERPENDICULAR PLANE
296
40. PLAN OF DISLOCATION
296
41-3. ENLARGEMENT OF VEINS ILLUSTRATED.
296
44. INCLINATION OF LODES IN DIFFERENT DIRECTIONS
302
45. INCLINATION OF DITTO IN SAME DIRECTION-
46.
SECTION IN TINCROFT MINE
47. A DOWNTHROW OF STRATA
•
48. LEAD LODES IN CARDIGANSHIRE
49. COPPER LODE IN CARDIGANSHIRE
50. CIRCULAtion of WATER IN VEINS
51. STRINGS OF OXIDE OF TIN IN SLATE
52. HEAVES OR FRACTURES IN CLAY-SLATE
53. LODE IN BALLESWIDDEN TIN MINE.
54. THE PIE LODES IN BALLeswidden
306
306
306
314
321
321
344
347
347
· 350
350
55.
GRIES AND HARD WORK IN BALLESWIDDEN
350
60.
61.
64.
56. SECTION AT WHEAL SETON MINE
57. SUPPOSED COURSE oF Sea Water at WHEAL SETON
58. SECTION AT COOK'S KITCHEN
59. SECTION OF LODES AT COOK'S KITCHEN
ELECTRICAL EXPERIMENT IN TUBE .
MINERAL LODE FORMED BY ELECTRICITY.
62. PLAN OF ELECTRICAL EXPERIMENT
63. MAP OF ST. JUST MINING DISTRICT.
INCLINED SHAFT AT BOTALLACK MINE
367
368
381
•
382
385
386
•
392
401
403
65. THE GREAT Carbona, ST. IVES CONSOLS
406
66.
SECTIONS OF THE GREAT FLAT LODE ON CARN BREA
409
67.
PLAN OF DEPOSIT AT EAST WHEAL LOVELL
410
68. NORTH LODE AT EAST WHEAL LOVELL
410
69. CARCLAZE TIN MINE, OPEN WORKING
418
70. PLAN OF CARCLAZE TIN MINE.
419
71. SECTION OF MULBERRY MINE.
420
72. SLIDY GROUND, HERODSFOOT MINE
434
73. LODE FORMED BY SHIFTING AT WHEAL MARY ANN MINE
435
74. REOPENING OF FISSURE IN DITTO
435
75. MAGNETIC CONDITIONS
437
76. DIAMAGNETIC CONDITION.
437
77. PRODUCTIVE PARTS OF LODES IN DOLCOATH
438
78. CAVERNS WORKED IN MONA MINE
440
79. SECTION ACROSS STRATA IN PARYS MINE.
447
80. SECTION OF WORKINGS IN PARYS MINE
81. NORTH DISCOVERY LODE, PARYS MINE
448
449
LIST OF ILLUSTRATIONS.
xvii
NO.
82.
GREAT OPEN CAST IN MONA MINE
83.
PAGE
451
SECTION IN MONA MIne
84.
ALTERNATING COPPER BEDs-Great ORMES HEAD
452
85.
CROSS VEINS IN GREAT ORMES HEAD.
456
86.
PRODUCTIVE AND NONPRODUCTIVE LODE IN GREAT ORMES HEAD.
456
87.
PART OF RODDERUP FELL MINE
456
462
88.
FRAGMENTS OF ROCK IN A LEAD VEIN
•
89. LODE, TIGRONY, WICKLOW
470
90.
PLAN AND SECTION OF FAULTED VEIN AT GLANDORE, IRELAND
91. A COMBY LODE
472
473
476
92. LODE IN WHEAL JULIA
477
93. COMBY LODE, CARN MARTH
478
94.
SPAR
CRYSTALLISED MINERAL Lode
95. FLUOR Spar Lode
.
478
480
96.
LODE IN THE VAN MINE
488
97.
494
ELECTRICITY CHANGING COPPER ORE
98. BORING BY MANUAL POWER
99. DIAGRAM SHOWING LENGTH OF PISTON-STROKE
100. A WET COMPRESSOR
IOI. THE SPRAY COMPRESSOR
I02.
103.
COLLADON COMPRESSOR
THREE-CYLINDER COMPRESSOR.
104. LARGE RECEIVER AND AIR PIPES
105.
106.
BEAUMOnt Camel
VERTICAL SIDE ELEVATION OF Trolly
107. FRONT ELEVATION OF BORER STAND
506
510
512
512
513
514
518
519
520
520
108. STAND AND TROLLY AT END OF Level
109. STAND ´USED AT SEVERN TUNNEL
521
521
112.
I14.
SINGLE-ACTING CRADLE DRILL
117. BORING TOOLS AND BITS
IIO-II. DIAGRAMMATIC ILLUSTRATION OF STANDS
SHAFT-SINKING STAND
113. THE DARLINGTON ROCK DRILL
115. A DOUBLE-ACTING DRILL
116. SINGLE-ACTING DRILL FOR QUARRY WORK
118. FRONT VIEW OF BORNHARDT'S FRICTIONAL MACHINE
521
522
525
526
526
527
528
533
119. SECTION OF BORNHARDT'S FRICTIONAL MACHINE
533
120.
SYSTEM BORNHARDT
534
121.
FIRING CABLES AND CONDUCTING WIRES
535
I22.
SHEATHED WIRE CABLES
535
123.
CARTRIDGES WITH CONNECTING WIRES
536
124.
ARRANGEMENT OF WIRES FOR FIRING
536
125.
PLAN SHOWING ARRANGEMENT OF BORING MACHINE
539
126.
THE CIRCULAR CUT SYSTEM OF BORE HOLES
540
b
xviii
LIST OF ILLUSTRATIONS.
NO.
127.
PAGE
ST. GOTHARD'S SYSTEM OF. BORE HOLES
54L
128.
AIROLO SYSTEM OF BORE HOLES
129. DUBOIS AND FRANÇOIS LEVELS AT ANZIN
130. POSITION OF THE BORERS
131. NUMBER AND POSITION OF HOLES.
541
541
542
542
132-3.
NUMBER AND POSITION OF HOLES IN HARD Rock
542
134. THE CIRCULAR CUT SYSTEM
•
543
135-6. THE SQUARE CUT SYSTEM AT THE HOOSAC TUNNEL, AMERICA'
137. CROSS CUT IN THE MINERA MINES
544
546
138. MIXED CUT SYSTEM AT BALLACORKISH
546
139. THE RADIAL CUT System
547
141.
142. POSITION OF LODE HOLES IN BALLACORKISH
143. PLANT OF ROCK-BORING MACHINERY
144. SINKING SHAFT TO CUT THE LODE.
140. ELEVATION AND PLAN OF CARTRIDGES OF COMPRESSED POWDER
PNEUMATIC ENGINE FOR UNDERGROUND HAULING
549
551
554
559
566
145. CUTTING THE LODE IN DEPTH
!
146. ADIT SHAFTS AND VENTILATORS
147. LODE DIPPING WITH THE HILL, AND CONTRARY TO THE INCLINE OF HILL.
148. TIMBERING OF SHAFT
566
568
570
57I
149. DIVIDERS OR BUNTONS
150. WALLINg of Shaft
572
572
151. PLAN AND SECTION OF SHAFT
152. SECTION OF SHAFT PARALLEL TO WALL Plates
573
574
153. TIMBERING A GALLERY
•
154.
FRAME OF TIMBERING
580
581
155. A TIMBERED GALLERY
•
581
156.
PROPS IN A LEVEL WEAK ON ONE SIDE .
582
157. WALLING END OF GALLERY
583
158. HORSE WHIM.
591
159. SKIPS TRAVELLING IN SHAFT
597
WAGGONS
164.
165.
160.
161. LOADING SKIPS IN SHAFT
162. HOOKS
163. DIAGRAM OF A METAL MINE.
UNDERGROUND STOPING.
TEAGUE'S VENTILATOR
598
599
600
601
603
614
166. DITTO COMPRESSED AIR VENTILATOR
615
167. BIRAM'S ANEMOMETER
615
168.
HORNBLOWER'S Valve
629
169. WOOLF'S VALVE, CONSOLIDATED MINES ENGINE
629
170. WOOLF'S VALVE, WHEAL ALFRED ENGINE
629
171.
DOUBLE-BEAT Valve
172. HUSBAND'S FOUR-BEAT Valve
630
631
NO.
173.
LIST OF ILLUSTRATIONS.
HYDRAULIC TRANSFER OF POWER
174. DIAGONAL SHAFT FOR HYDRAULICS
175. HUSBAND'S SAFETY GOVERNOR
176. RODS OF MAN ENGINE
177. SINGLE-ROD MAN ENGINE
178. Fox's Wedge
WEDGE .
179.
180.
HAMMERS
CAT'S-HEAD HAMMER
181. COBBING HAMMER
xix
PAGE
635
635
647
650
651
653
654
654.
654
182.
BUCKING HAMMER
654
183. THE PICK
6-55
184. THE Level
660
185. THE THEODOLITE
661
186. THE TRANSIT INSTRUMENT
665
187.
SURVEYORS' PLOTTING DIAGRAM
667
188.
DIAGRAM FOR DETERMINING DIRECTION OF FAULT
672
189. DIAGRAM ILLUSTRATING MOVEMENT OF FAULTS
674
190. HOEFER'S GRAPHIC METHOD
675
191. SPECIFIC GRAVITY Balance
699
192. WASHING KILN
714
193. STONE Breaker
194. STONE GRINDER
195. CORNISH CRUSHER .
719
720
722
196. CRUSHING MILL, FRONT AND SIDE ELEVATION
725
197.
STAMPING MACHINE
198.
END VIEW OF DITTO
199.
CALIFORNIAN STAMP
732
732
733
200.
DIRECT-ACTING STEAM STAMPS
201. HUSBAND'S PNEUMATIC STAMPS
734
735
202.
DINGEY'S PULVERIZER
737
206.
207.
208.
209.
CLASSIFYING LAUNDERS
210.
HODGE'S CLASSIFIER
2II.
CONE SEPARATOR
212.
203. JORDAN'S PULVERIZER
204.
PERFORATIONS IN SIZING PLATES
205. CONTINUOUS CYLINDRICAL TROMMEL
SINGLE CONICAL TROMMEL
SEPARATE CYLINDERS AND TROUGHS
TRIANGULAR DOUBLE TROUGHS
741
745
746
746
749
752
753
•
754
756
CONTINUOUS SAND JIGGER
213. ARGALL'S JIGGER
214. COMPOUND JIGGER.
215. COLLOM'S TAPPET JIGGER
216. SLIME OR BUDDLE JIGGER
759
760
761
761
763
XX
LIST OF ILLUSTRATIONS.
NO.
217.
BUDDLES AND TABLES
218. THE KNIFE OR IMPELLER BUDDLE
219. THE ROUND BUDDLE
PAGE
764
765
766
220.
CENTRE-HEAD BUDDLE
767
221.
THE ARMS TO CENTRE-HEAD BUDDLE
767
222.
CONCAVE BUDDLE
767
223.
RING Buddle
768
224.
226.
BORLASE'S INCLINED BUDDLE
225. DEAD FRAME
OXLAND AND HOCKING'S CALCINER
227. TOSSING AND PACKING
228. IRON LODE AT BRENDON HILLS
229.
HODBARROW IRON MINE
230. CRUSH IN IRON MINE
231. EGREMONT IRON MINE
769
770
772
778
1
799
803
804
805
1
FOLDING PLATES.
ANCIENT CHARTER RELATIVE TO MINES IN THE MENDIPS
MINERAL VEINS AND Cross COURSES IN THE DISTRICT OF CARN
ILLOGAN
to face p.
134
BREA AND
to face p.
201
BRITISH MINING.
BOOK I.
HISTORICAL SKETCH OF BRITISH MINING.
+
'
CONTENTS OF BOOK I.
CHAP. I. MINING PREVIOUS TO THE ROMAN INVASION OF BRITAIN.
II. MINING DURING THE ROMAN OCCUPATION.
"2
III. MINING TO THE EIGHTEENTH CENTURY.
IV. MINING FOR TIN AND COPPER TO THE END OF THE EIGHTEENTH CENTURY.
""
""
V. MINING FOR Lead, Silver, ETC., TO THE END OF THE EIGHTEENTH CENTURY.
"
VI. GOLD, PLUMBAGO, IRON Ore, and SundrIES TO THE END OF THE EIGHTEENTH CENTURY.
BRITISH
MINING.
BOOK I.
HISTORICAL SKETCH.
CHAPTER I.
MINING PREVIOUS TO THE ROMAN INVASION OF BRITAIN.
TIN.-There are certainly evidences which appear to prove that the British
Isles have yielded mineral treasures, for the use of man, for not less than
three thousand years. Tradition whispers―very indistinctly it is true—that
certain spots were visited, long before the Christian era, by traders from
an Eastern country, who sought for, and discovered, a district producing tin.
Indications of old mine workings-such as holes pierced in the faces of
the cliffs, and shallow pits dug on the sides of the hills—are found existing to
the present day, throughout the length and breadth of Cornwall, which are
unmistakably of great antiquity. We learn from the present inhabitants that
these are "old men's workings," the remains of the "Sarcens," or strangers
-"Jews' pits" and the like-but of the age of those diggings we glean
nothing. Vast heaps of detrital matter are not unfrequently met with,
evidently the result of subterranean-but shallow-operations, and these are
in many places called "Attal-Saracen,
or, the waste of the stranger, and
in others they are spoken of as "Jews' leavings." From these we are
led to infer, not that Saracens ever worked the tin mines, but that oriental
strangers did, in this country, establish those searches for a metal valuable
to them.
It should not be forgotten that in the time of Moses at least six metals
were known. He says of the spoils of the Midianites, "Only the gold
and the silver, the brass, the iron, the tin, and the lead" shall be purified
by fire.t
Although we have only conjecture to guide our inquiries into the age of
the ancient mineral works in these islands, there are collateral evidences
supporting the hypothesis, which points to the very early employment of
* Attal-Sarsen is probably the correct term, although commonly pronounced "Saracen," under some
misconception that the name applies to the Saracens or Moors. Sarsen signifies simply the stranger,
and in this sense it is applied to the “Sarsen Stones" on Salisbury Plain, meaning stones brought fiom
some other district.
+ Numbers xxxi. 22,
B
2
[BOOK I.
HISTORICAL SKETCH.
Cornish tin in the manufacture of the brass of the sacred writings, and the
bronzes of Assyria and of Egypt. It is desirable that a few of those evidences
should be examined.
Ezekiel (chap. xxvii. ver. 12) the prophet, who wrote about six hundred
years before Christ, speaking of the commercial wealth of Tyre, says:
"Tarshish was thy merchant by reason of the multitude of all kinds of riches;
with silver, iron, tin, and lead, they traded in thy fairs." The Greeks used
tin before the Trojan war. This metal is mentioned by Homer as forming a
corslet presented by the King of Cyprus to Agamemnon. Consequently tin
must have been known at least sixteen centuries before Christ. From this
it is evident that a large trade in the metals named must have been estab-
lished from a remote period. Herodotus, who wrote B.C. 440, admits his
want of knowledge as to the source from which amber is derived, and he
continues, "Neither am I better acquainted with the islands called the
Cassiterides, from which we are said to have our tin."
Wheeler, in his "Geography of Herodotus," correctly says: "He knew
the Etruscans, whose commerce extended far and wide, and he had some
dim, doubtful notions, about the Cassiterides, or Tin Islands. But of the
inhabitants of our present France, or Britain, or Germany, the universal
geographer had heard nothing."
Bronze weapons, tools, and ornaments were used by man in the very
youth of his history. This metal is well known to be an alloy of copper with
tin. There can be no question but that the tin was obtained from one of
three sources. It was either derived from some of the islands of the Indian
Archipelago, or from Spain, or from the British Isles. Mr. W. D. Cooley, in
his "Maritime and Inland Discovery," vol. i. p. 131, writes evidently without
sufficiently examining the question. "There can be no difficulty in deter-
mining the country from which tin first arrived in Egypt. That metal was
in all ages a principal export of India: it is enumerated as such by Arrian,
who found it abundant in the ports of Arabia, at a time when the
supplies of Rome flowed chiefly through that channel. The tin mines of
Banca are probably the richest in the world. But tin was unquestionably
brought from the West at a later period." Dean Vincent, in his "Commerce
and Navigation of the Ancients in the Indian Ocean," refers especially to
the Periplus of Arrian-not the Arrian of Nicomedia, who wrote the Life of
Alexander the Great-but a merchant of Alexandria in Egypt, who, having
himself made many voyages to India and Ceylon, collected the information
obtained, and published it under the title of "The Periplus of the Erythræan
Sea." While the exports from Masuah-Abyssinia are stated to be ivory
and rhinoceros' horns; amongst the imports we find white copper for orna-
ments and coins; brass for culinary vessels and personal ornaments;
iron for spear-heads and of Indian temper. The imports into Abalites,
close to the Straits of Babelmandeb, consisted amongst other things of tin
in small quantity. Kane, a port on the coast of Arabia, imported from
Egypt, amongst cottons, silks, and similar articles, brass and tin. The
imports into Barugaza, a port in the Gulf of Cambay, included brass, tin, lead,
ore of cinnabar, and stibium (the sulphide of antimony) for tinging the eyes.
The port of Baráhi-believed to be the extreme point reached by Arrian in
CHAP. I.]
ANCIENT TRADE IN TIN.
3
his voyages-lying midway between Goa and Cape Comorin, received from
Egypt, stibium (antimony), with brass, tin, lead, cinnabar, and orpiment. In
all this we find that tin was sent to Eastern ports, but we discover no trace of
tin as being imported into Egypt from India. Tin was evidently known and
recognised as an article of traffic in the most ancient times; but instead
of being brought from the East to the West by the merchants of Egypt, it is
invariably exported from that country to the East.* All this is strongly
opposed to the statement which has been quoted from Cooley's work. The
existence of tin in India is undoubted. The island of Banca and many of
the smaller neighbouring islands must have produced tin, and this metal
was also found in Burmah, Siam, and Malacca, the southern promontory
of Asia. It is not improbable, therefore, that some tin might have been
brought into the Red Sea, or into Egypt, by an overland route from
India.
Layard, for example, in his "Nineveh,” vol. ii. p. 419, says: “I am not
aware of the existence of tin within the limits of Assyria. Still the Assyrians
and the adjoining nations must have obtained this metal from their own
dominions, or from some country to the east of them, as it is mentioned among
the objects of tribute brought to the Egyptians from that part of Asia. The
probability is, that the tin used in the manufacture of the bronzes of the
Assyrians was brought by caravans from the East, and that the copper was
procured from the copper mines in Arabia." These quotations have been
made for the purpose of showing that a considerable amount of ingenious
argument has been expended in the endeavour to prove one side only of
a question. The navies which were employed in bringing treasures to
Solomon might have brought tin from the East, at the same time as the
Tyrian merchants were obtaining the same metal from the West, but we do
not discover that they traded to any extent in that metal. Tradition and
history regard the people of Phoenicia as the merchant traders who dis-
covered—while Rome was yet in its infancy-the Western land from which
tin could be obtained in abundance. There appears to be no reason for
doubting that the Phoenicians established themselves in Cyprus, and in that
island manufactured bronze and brass. "The inventor," says Kenrick,† "of
the manufacture of brass-of the tongs, the hammer, the lever, and the anvil
-who gave to Agamemnon the breastplate of steel, gold, and tin, was a
king of Byblus, who migrated thence and founded Paphos.
The ore
'calamine' (carbonate, or silicate of zinc), which furnishes the ingredient
for the manufacture of brass, and which was found in great abundance in
Cyprus, as well as copper ore, was called cadmia." This statement of the
abundance of zinc ore in Cyprus is open to correction. "Nowhere," continues
Kenrick, “in the ancient world were mining operations carried on upon a
larger scale or by more scientific methods than in Spain. . . . From the
accounts of Posidonius, whom Strabo, Diodorus, and Pliny follow, it is
evident that in the last century before the birth of Christ, mining works
were carried on there with stupendous labour, and the application of the
* "The Cassiterides: an Inquiry into the Commercial Operations of the Phoenicians in Western Europe,
with particular reference to the British Tin Trade." By George Smith, LL.D., F.A.S. 1863.
† "Phoenicia," p. 260. By John Kenrick, M.A.~ 1855.
B 2
4
[BOOK I,
HISTORICAL SKETCH.
best science of the age." The author then, drawing evidently on his imagi-
nation, describes mining works as extensive and as skilfully arranged, as
any that are to be found in the present day in any part of the world. Suffice
it to say, that the relics of ancient works which are still discoverable in
Spain, are invariably of the same rude character as those which we meet
with in these islands.
A few words on the origin of the Phoenicians may serve to place the
question under consideration in a more satisfactory light. The Phoenicians
seem first to have come from the sea of Erythra, which includes the Indian
Ocean, the Red Sea, and the Persian Gulf. They were driven from their
native land by an earthquake. They settled first on the Assyrian lake and
subsequently on the sea shore, founding the city of Sidon,* which was built
when Abraham lived in Canaan.† The Phoenicians were a branch of the
great Semitic or Aramæan family of nations, and they were nearly allied
to the Jews in the time of Solomon, their language closely resembling the
Hebrew.‡ In the days of Sardanapalus, the chief Phoenician cities paid
tribute to that conqueror, and Sennacherib crossed the Euphrates and
received the submission of Syria and Phoenicia.§ The Phoenicians are also
said to have been emigrants of a serpent-worshipping tribe who came from
a district in Afghanistan. They were a more ancient people than the Jews
with whom they traded, but they were never conquered by them. ||
Posidonius, Strabo, Diodorus, and other writers appear satisfied that
the Phoenicians established themselves in Spain, and that they made Gadez
(Cadiz) a port in the early days of their occupation. Twelve centuries before
Christ, has been assigned by some authors, as the date of their occupation.
The geographical position of this port renders it a place of considerable
importance to our inquiry, as from it a maritime people would certainly, in
time, have reached Britain. Diodorus the Sicilian, writing only eight years
before the birth of Christ, and consequently repeating what had been told by
more ancient chroniclers, states that the Phoenicians undertook frequent
voyages by sea, in the way of traffic as merchants; and that they established
many colonies both in Africa and Western Europe, passing beyond the Pillars
of Hercules, and building a city, Gades. This historian then informs his
readers that a severe storm drove some Phoenician ships afar off into the
main ocean, and that, driven before the tempest, they at length discovered
the British Isles. The following passage from Diodorus demands especial
attention :-
'We will now," he says, "give an account of the tin which is produced
in Britain. The inhabitants of that extremity of Britain which is called
Bolerion,¶ both excel in hospitality, and also, by reason of their intercourse
with foreign merchants, are civilised in their mode of life. These prepare
the tin, working very skilfully the earth which produces it. The ground is
rocky, but it has in it earthy veins, the produce of which is brought down
and melted and purified. Then when they have cast it into the form of
cubes, they carry it to a certain island adjoining to Britain, and called Iktis.
* Kenrick's "Phoenicia."
+ Phillip Smith's "Ancient History."
‡“ Penny Cyclopædia," art. Phoenicia.
§ Phillip Smith's "Ancient History."
Kenrick's "Phoenicia."
¶ This term appears to have been exclusively applied to the district of the Land's End. See Milton.
CHAP. I.]
PHOENICIANS DISCOVER BRITAIN.
5
During the recess of the tide the intervening space is left dry, and they carry
over abundance of tin to this place in their carts. And it is something
peculiar that happens to the islands in these parts lying between Europe
and Britain; for at full tide, the intervening passage being overflowed, they
appear islands, but when the sea retires a large space is left dry, and they
are seen as peninsulas. From hence, then, the traders purchase the tin of
the natives, and transport it into Gaul, and finally travelling through Gaul
on foot, in about thirty days they bring their burdens on horses to the mouth
of the river Rhone."*
The antiquity of bronze is generally admitted, although there is con-
siderable diversity of opinion as to the period of the, hypothetical, Bronze
Age; the probability being, that weapons and ornaments of this alloy were
manufactured in the same ages by some people, when other races were
engaged in making implements of flint. A Stone Age, and a Bronze Age,
might, therefore, have been contemporaneous.†
Bronze and brass are frequently confounded: in old books the terms
are used indifferently for the same metal. The former is made by the
direct union of two metals-copper and tin-and the oldest metallurgists,
discovered, by some empirical process, the true proportion for pro-
ducing the hardest alloy. Brass was of very uncertain manufacture.
Accident must have led some early metallurgists to the discovery that the
red metal, copper, became yellow when it was melted in contact with a
peculiar earth, cadmia-our calamine. Zinc was not known as a metal
until 1509, when Erasmus Ebener separated it from the calamine of the
furnaces at Rammelsberg. The manufacturers of bronze and brass appear
to have been, from a very early period, some branches of the Phoenician
people, and the Assyrians. Probably some of the Jewish tribes were also
skilled metallurgists. The copper for those alloys was obtained, it is
tolerably certain, from Arabia and from Cyprus. The tin could only have
been procured from India, from Spain-in which country it existed in small
quantities-and from Britain, where in those days it must have existed in vast
abundance, in the alluvial deposits, from which it was easily separated by
the rudest process of washing. The black oxide of tin, when exposed to
the heat of burning wood, melting very readily into a beautifully white
metal, would soon attract the attention of the most untaught of men.
There has been much discussion on the terms used in the sacred writings
and the old historians to signify tin: a few remarks will not therefore be out
of place. Tin is named among other metals by Moses sixteen centuries before
the Christian era; and Homer, who wrote eight centuries later (?), represents
it to have been used at the siege of Troy, apparently in the eleventh century
before Christ.
The Greek writers evidently knew that tin was obtained from the northern
confines of Spain and Lusitania, and likewise from Britain; being brought
overland through Gaul.
Roman writers at a later date, Pliny for example, give the name of
* Diodorus, lib. v.
†Thomas Wright "On the true Assignation of the Bronze Weapons supposed to indicate a Bronze
Age in Western and Northern Europe.'
""
"History of Inventions, Discoveries, and Origins." By John Beckmann. Bohn's edit. 1846.
6
[BOOK I.
HISTORICAL SKETCH.
plumbum candidum to the cassiteron or tin of the Greeks; and he protests
against the "fiction" of its having been obtained from any islands in the
Atlantic Ocean, or anywhere but from Spain and Lusitania. The name of
stannum he attributes to a metal which he describes as being intermixed
with silver and plumbum nigrum (or lead).* Julius Cæsar,† a century later,
wrote, "Nascitur ibi plumbum album," which many have supposed to be our
tin. It is doubtful if Julius Cæsar intended tin. At all events he speaks of
its being produced in the inland parts of Britain, which is true of lead,
but not so of tin.
The Rev. Samuel Greathead writes: "The Latin term stannum appears
to have been adopted from the ancient Cornish stean, or the Welsh ystaen,
for which plum gwynn (synonymous with plumbum album) is sometimes
used."+
Dr. Borlase, in his "Antiquities of Cornwall," deals with the whole ques-
tion, and his remarks are, therefore, well worthy of attention, and their
introduction in the accompanying notes requires no apology. §
* Pliny's "Natural History," lib. xxxiii. cap. 16, 17.
+ Cæsar's "Bell. Gall." v. IO.
I "On the Knowledge and Commerce of Tin among Ancient Nations." By the Rev. Samuel Great-
head. ("Transactions of the Geological Society of Cornwall," vol. ii.)
§ EXTRACTS FROM BORLASE'S "ANTIQUITIES, HISTORICAL AND MONUMENTAL, OF THE COUNTY OF
CORNWALL.”
a. That the western parts of this island (viz. Devon and Cornwall) were first discovered by the Phoni-
cians, and by them inhabited, has no other foundation than that the names of places in these parts may
be derived from Phoenician words, which is too deceitful a ground to build on, especially considering they
may all be found in the British tongue, which, as spoke in the several extremities of the island (where the
Phoenicians never traded), has great affinity with the Hebrew; and therefore we must take care how we
attribute to the Phoenician traders names which may be found in our own British, a language derived in a
great measure from the Hebrew, to which primarily the Phoenicians also owed their whole language.
b. There is another remarkable voyage of the Phoenicians mentioned in ancient history, but continued
down to us with great uncertainties of circumstance and time.* Himilco was sent forth from Carthage
to make a voyage to the north at the same time that Hanno, a Carthaginian, was dispatched the contrary
way, to explore the southern coasts; but at what time those two leaders lived, whether a little before the
second Punic war (as indeed the names seem to intimate), or much more anciently, in the time of Darius
Nothus, is very undetermined, as Camden thinks, as also whether the Periplus of the latter, written in
Punic, shall be of any authority, though, by Festus Avienus, affirmed to have been perused by him.
If the Phoenicians in their northern voyages coasted along the shores of Spain and Gaul (as was
doubtless the most ancient way of navigating), then the shores of Britain opposite to Gaul must have been
first known to them; but at whatever part of our island they first arrived, the western parts had certainly
the greatest share of their commerce, if not the whole. The Phoenician business into these parts was not
conquest and glory, but trade; and from Gades they traded to Britain, bringing salt, crockery, and
brazen ware.† What they came for was tin, lead, and skins, but especially the former, which was soon
found to be so useful a metal that it grew famous over all the then known world, and encouraged the
Phoenicians to continue and engross the trade to this island.
But the principal inducement for the Phoenicians to frequent our coasts was tin, a metal far transcend-
ing both the beauty and the use of lead. This metal was anciently also found in Lusitania‡ and Gallicia, but
in too small quantities to satisfy the expectations of so many cities and countries as were desirous to have it.
The Phoenicians, therefore, having discovered abundance of tin in some small British islands, among
which they probably reckoned the west of Cornwall, carried on so considerable a trade here, that from
these little islands only they were enabled to supply the greatest part of the world with this useful metal.
All the cities and nations of the Mediterranean had their tin chiefly from the Phoenicians, and they from
the islands of Britain. I say chiefly, for though Spain yielded some little share of this commodity, yet it
must have been a very small quantity, or the Phoenicians from Gades would doubtless have supplied them-
selves at home, and never have crossed the Atlantic Ocean at such hazard and expense in the infancy of
navigation. This metal was not only sent up the Mediterranean, but exported even as far as India itself.
*Himilco's Voyage, p. 27.
+ Strabo, lib. iii.
Portugal, Pliny, lib. xxxv. cap. 16.
CHAP. I.]
BORLASE'S “ANTIQUITIES"
7
The only districts in the continent of Europe producing tin, were Saxony,
Bohemia, North-Western France, and Finland. The only countries from
Such an extensive trade required proportional supplies, and as we read of no tin mines worth notice east
of the Dunmonii,* all the Phoenician trade for this metal must have been confined to that country now
called by the two names of Devonshire and Cornwall, and the small islands adjacent to Cornwall,
now Scilly (or Sylleh) Islands. Among these the islands were most productive, and therefore most
famous in history; and from the tin they yielded, called Cassiterides. They were either named so by the
Grecians,† from the Greek word, Kaσoirepov (Tin), or, it being confessed that both the Chaldeans and
Arabians called tin by a name of like sound, so named by the Phoenicians themselves, which I must
observe is so much the more probable, because we find these islands called Cassiterides long before the
Grecians either traded thither or knew where the islands lay; for Herodotus, who lived about 440 years
before our Saviour, says that he knew nothing of the islands Cassiterides, from whence their tin came.‡
Now, with great deference to Bochart's judgment, let it be observed that it is highly improbable the Greeks
should give name to islands they knew not where to find, and consequently had no communication with,
but through means of the Phoenicians. Solinus calls them Insula Silurum, or Insula Silura, of which the
present name, Scilly, may seem to retain enough to justify him; but it is much to be suspected whether
the ancient geographers knew the real situation of the Silures, and whether the Scilly Islands were not
mistaken for islands adjacent and belonging to the true country of the Silures, or South Wales. However,
if there be any truth in what Tacitus relates, viz. that the Silures were opposite to Spain, it can only be
true of the Silures of the Scilly Islands; and if some of their inhabitants were like the Spaniards, it is not
near so surprising as that the inhabitants of South Wales should be so. The inhabitants of Scilly have far
more of the characteristics of the Spaniards than the people of South Wales. The Phoenician colony at
Gades might probably send over some of their inhabitants to islands which afforded them so great a profit,
in order the better to superintend and engross so profitable a commerce. Their descendants might retain,
even to the time of Tacitus, the swarthy complexion and curled hair of the people they were sprung from.
Here we find a resemblance which has history to support it, and no solecism in geography to weaken or
reject it.
From these islands the Phoenicians had their treasures of tin, § and were exceedingly jealous of their
trade, and therefore so private and industrious to conceal it from others, that a Phoenician vessel, thinking
itself pursued by a Roman, chose to run upon a shoal and suffer shipwreck, rather than discover the least
track or path by which another nation might come in for their share of so beneficial a commerce.
c. Borlase supposed the Greeks to have visited Britain before Christ. They are thought by him to
have passed through the Straits of Gibraltar as early as the time of Alexander the Great. Bochart || says
the Grecians did not come until 117 years before our Saviour. Pliny says that Britain was famous in Greek
monuments long before the times of the Romans; and Polybius, a Greek by nation, who flourished about
200 years before our Saviour, though a constant companion of Scipio Africanus, promised to write of the
British Isles and rŋs kaoσirnpo Karaokεvns (the methods of preparing tin), and made good his
promise, as Strabo says, a task which so cautious a writer as Polybius would never have undertaken had
there not been sufficient materials at that time to be procured for the groundwork of such an history.
d. I am sensible that the learned are of opinion that the Romans never came west of the river
Tamar. All historians agree that the southern part of Europe was conquered by Claudius Cæsar. It is
not unlikely that Cornwall, the southernmost part of all this island, may be included in this computation.
"Again, if we may conclude anything from the words of Tacitus,¶ Fert Britannia aurum et
argentum et alia metalla prætium victoriæ,' we must think that the Romans made sure of the most con-
siderable mines, as well as harbours, in Agricola's time, if not before. Again, Glaucus, in his celebrated
speech, has these words, 'Neque sunt nobis arva, aut metalla,** aut portus, quibus exercendis reserve-
mur;' intimating that the pasture, the metals, and the ports in other parts of the island had proved so
many temptations to the avaricious Romans; but that there was no such thing in the country where they
were."
e. What the ancient method was of preparing tin for the furnace we cannot say, but Polybius, the histo-
rian, is said to have described it, and that work is commended by Strabo, but now lost, with other valuable
compositions of that judicious author. The short description which we have of the tin trade in Diodorus
Siculus (lib. iv. p. 301, edit. Hanov. 1664) must not be omitted, though it is too general for us to learn
many particulars from it.
"These men," says he, meaning the tinners, "manufacture their tin by working the grounds which
produce it with great art. For though the land is rocky it has soft veins of earth running through it, in
+ Bochart, p. 650.
* Cornish men, Cornwall comprehending Devon and Cornwall.
Ουτε νησός οιδα Κασσιτερίδας εὅσας εκ των ο κασσιτερος ἡμὶν φοίτα. In Herod.
Strabo, lib. iii. De Cassiter.
See Diod. Sic. lib. v. p. 650.
Tacitus, "Vit. Agric."
** Tacitus, Ibid.
8
[BOOK I.
HISTORICAL SKETCH.
which the Phoenicians could have obtained this metal, were Spain and
England; all the other places being too remotely inland, and it is question-
able if any considerable quantity of tin was procurable from any of them in
those days.* Sir George Cornewall Lewist says Gadeira or Gades was an
ancient foundation of the Phoenicians of Tyre. "The foundation of Gades
is placed by Mela at the time of the siege of Troy," but this is probably a
legend similar to that of Brutus colonising Britain. The Periplus of Scylax,
composed about 340 B.C., however, mentions the colonies and factories of
the Phoenicians and Carthaginians on the western coast of Iberia.
which the tinners find the treasure, extract, melt, and purify it. Then shaping it [by moulds] into a kind of
cubical figure, they carry it off to a certain island lying near the British shore, which they call Ictis; for at
the recess of the tide, the space betwixt the island and the main land being dry, the tinners embrace the
opportunity, and carry their tin in carts, as fast as may be, over to the Ictis (or port), for it must be observed
that the islands which lie betwixt the continent and Britain have this singularity, that when the tide is full they
are real islands, but when the sea retires they are but so many peninsulas. From this island the merchants
buy the tin of the natives and export it into Gaul; and, finally, through Gaul, by a journey of about thirty
days, they bring it down on horses to the mouth of the Erydanus, meaning the Rhone." In this description
it will naturally occur to the inquisitive reader to ask where this Ictis was to which the Cornish carried
their smelted tin in carts, and there sold it to the merchants. I really cannot inform him, but by the Ictis
here it is plain that the historian could not mean the Ictis, or Vectis, of the ancients (at present called the
Isle of Wight), for he is speaking of the Britons of Cornwall; and, by the words, it should seem those of
the most western parts, that is, those who live at the extreme end of Britain, called Belerium, find, dress,
melt, carry, and sell their tin, &c. Now it would be absurd to think that these inhabitants should carry
in carts their tin near two hundred miles (for so far distant is the Isle of Wight from them), when they had
at least as good ports and harbours on their own shores as they could meet with there. Besides, these
inhabitants are said, in the same paragraph, to have been more than ordinarily civilised by conversing with
strangers and merchants. Those merchants, then, must have been very conversant with Cornwall, there
trafficked for tin, that is, there bought, and thence exported the tin, or they could have no business there.
Their residence would have been in some of the ports of Hampshire, and Cornwall could scarce have felt
the influence of their manners, much less have been improved and civilised by them at that distance.
Again, the Cornish, after the tin was melted, carried it at low water over to the Ictis in carts. This will by no
means suit the situation of the Isle of Wight, which is, at least, two miles distant from the main land, and
never, as far as we can learn, has been alternately an island and a peninsula, as the tide is in and out. The
Ictis, therefore, here mentioned must lie somewhere near the coast of Cornwall, and must either have been
a general name for any peninsula or creek, Ik being a common Cornish word denoting a cove, creek, or
port of traffic.
* It is easier to determine the locality of the "land of tin " (Britain and the Scilly Isles) than that of
the "amber coast," for it seems to me very improbable that the old Greek denominative kaσoirεpos, which
was in use even in the Homeric times, is to be derived from a stanniferous mountain in the south-west of
Spain, called Mount Cassius, and which Avienus, who was well acquainted with the country, placed
between Gaddir and the mouth of a small southern Ibernus (Ukert, “Georgr. der Griechen und Römer,'
Iheit in. Abth. i. s. 479).
Kassiteros is the ancient Indian Sanscrit word Kastîra. Zinu in German, den in Icelandic,
tin in English, and tenn in Swedish, is in the Malay and Javanese language tinnah; a similarity of
sound which reminds us of that of the old German word glessum (the name given to transparent amber)
to the modern "glas," glass. The names of articles of commerce pass from nation to nation, and
become adopted into the most different languages. Through the intercourse which the_Phoenicians,
by means of their factories in the Persian Gulf, maintained with the east coast of India, the Sanscrit word
kastira, expressing a most useful product of Further India, and still existing among the old Aramaic idioms
in the Arabian word kasdir, became known to the Greeks even before Albion and the British Cassiterides
had been visited (Aug. Wilh. v. Schlegel, in the Indischen Bibliothek, Bot. ii. s. 893; Benfeg, Indica,
s. 807; Pott, etymol. Forschungen, Ih. ii. s. 414; Lassen, indische Alterthumskunde, Bot. i. s. 239). A
name often becomes an historical monument, and the etymological analysis of languages, which is some-
times ignorantly derided, is not without its fruit. The ancients were also acquainted with the existence of
tin (one of the rarest metals on the globe) in the country of the Artabri and the Callaici, in the north-west
part of the Iberian continent (Strabo, lib. iii. p. 147, Plin. xxxiv. c. 16), nearer of access, therefore, for
navigators from the Mediterranean than the Cassiterides (Astrymides of Avienus). When I was in
Galicia in 1799, before embarking for the Canaries, mining operations were still carried on, on a very poor
scale, in the granitic mountains. (See my Rel. Hist. t. i. pp. 51 and 53.) The occurrence of tin in this locality
is of some geological importance on account of the former connection of Galicia, the peninsula of Brittany,
and Cornwall.-Note to Humboldt's "Cosmos," vol. ii. note 129, Sabine's translation.
"An Historical Survey of the Astronomy of the Ancients,” p. 449. By the Right Hon. Sir George
Cornewall Lewis.
CHAP. I.]
THE ISLES OF THE CASSITERIDES.
9
From Gades the adventurous Tyrians are thought to have steered
their ships along the coasts of Spain, in search of amber, which was in
great request, and tin. Eventually they reached the British islands, and
were rewarded for their enterprise, by the discovery of a land rich in the
metal for which they sought.
"It cannot be doubted," says Lewis, "that Britain was the country from
which the tin sold by the Phoenicians to the Greeks was chiefly procured."
Herodotus had heard of the Tin Islands-the Cassiterides-but he was unable
to obtain any information as to their situation. He says: "Of that part
of Europe nearest the west I am not able to speak with decision. .
I have endeavoured, but without success, to meet with some one who from
ocular observation might describe to me the sea which lies in that part of
Europe. It is nevertheless certain that both our tin and amber are brought
from those extreme regions."*
The islands of Scilly have been fixed on by almost all old writers as the
Tin Islands of the Phoenicians, and this, notwithstanding the fact that no tin
is now discoverable in them. Dr. Borlase, evidently feeling the difficulty
which exists in the endeavour to prove that the Scilly Islands were the
Cassiterides of the ancients, supports the hypothesis that the sea has been
continually disturbing the low lands in which detrital tin would have been
found. He writes: +-
<
"The sea is perpetually preying upon these little islands, and leaves
nothing where it can reach but the skeleton, the bared rock.
.. Many
hedges now under water, and flats which stretch from one island to another,
are plain evidences of a former union subsisting between these now distinct
islands. History speaks the same truth. The isles of Cassiterides,' says
Strabo, are ten in number, close to one another: one of them is deserted
and unpeopled, the rest are inhabited.' But see how the sea has multiplied
these islands: there are now reckoned more than one hundred and forty, into
so many fragments are they divided." After mentioning several pheno-
mena which indicate submergence, Borlase writes again: "Tin mines they
certainly had in these islands two hundred years before Christ. What is
become of the mines? for the mines at present to be seen show no marks of
their being ancient." In support of the view that considerable alterations have
occurred in the relative position of land and sea, he quotes the following state-
ment from Heath: § "A person taking a survey of the channel in the year
1742, took one of his stations at low water, as he told me, upon this rock (viz.
the Gulph Rock, midway between Penzance and Scilly), where he observed a
cavity like a brewer's copper, with rubbish at the bottom, without being able to
assign a cause for its coming there." The rock alluded to is the Wolf Rock of
the present day, upon which a lighthouse now stands, an example of structural
engineering of the highest class. "This," says Borlase, "could be no other
than a rock basin, and consequently this rock is greatly sunk-by being now
entirely covered with the sea-at least nine hours in twelve." This remarkable
rock is of igneous origin, and it stands, a bold mass, in the deepest part of
the channel, showing no indication of any alteration. The rock is a "phono-
+ "Ancient and Present State of the Scilly Islands,” p. 90.
§ Heath's "Account of the Scilly Islands," p. 157.
*Herodotus's "Thalia," cxv.
Strabo's "Rerum Geographicarum," lib. iii.
IO
[BOOK I.
HISTORICAL SKETCH.
lite, which occurs occasionally in the form of lava flows, but more commonly
in conical masses or hills. It sometimes exhibits well-marked columnar
structure."* The Wolf Rock has been usually considered as the solitary
example in this country of this class of rock formation. A careful exami-
nation of the rocks along the coast from Cape Cornwall to Sennen, leads
to the belief that examples of the same mineral formation are to be
discovered in these cliffs. In many places, especially near Cape Cornwall,
the columnar structure of Basaltic rocks is well marked.
After discoursing in his own unsatisfactory way of the alterations in the
level of the land and the depredations of the sea, Borlase says:-"I con-
clude, therefore, that these islands have undergone some great catastrophe,
and besides the apparent diminution of their islets by sea and tempest, must
have suffered greatly by a subsidence of the land (the common consequence
of earthquakes), attended by a sudden inundation in those parts where the
above-mentioned ruins, fences, mines, and other things, of which we have no
vestiges now remaining, formerly stood."
That a great inundation occurred, probably about the year 1014, appears
proved by the submerged forests seen in the Mount's Bay, near Penzance,
and several other places. The Saxon Chronicle gives this account: "Hoc
item anno in vigiliis Sancti Michaelis contigit magna ista maris inundatio
per latam hanc terram quæ longius expatiata, quam antea unquam, demersit
multa oppida et hominum numerum inenarrabilem.”
The legendary story of the flood which separated the Scilly Islands from
the Land's End may be dismissed from consideration. Indeed, the inunda-
tion mentioned in the Saxon Chronicle is no doubt an exaggerated descrip-
tion of a small phenomenon. The same geological changes which separated
Britain from the Continent produced, there can be but little doubt, the isola-
tion of Scilly, at a period long before the existence of man in these islands.†
When the stream works of the Cornish tinners come to be described it
will be rendered evident, that the detrital deposits are clearly indicative of
the wearing down of extensive tracts of country, and it will also be shown
that there has been more than one alteration in the relative levels of the sea
and land. It is therefore within the limits of possibility that stanniferous
deposits which once existed in the isles of Scilly may have suffered submer-
gence, or have been washed away. The rise and fall of the tides certainly
produce the phenomena of changing a promontory into an island, and the
contrary, but not to the extent required by the narrative of the ancient
historians. But there exists the difficulty that scarcely any remains of mine-
workings are to be found in any of these islands, neither do any of the streams,
or the foreshores, now yield detrital tin.
In relation to the only trace of mines in the Scilly Islands, Dr. Borlase
writes: "On these downs we saw a large opening made in the ground, and
dug about the depth of a common stone quarry, and in the same shape.
There are several such in the parish of St. Just, Cornwall, where they are
called Koffens,' and show that the more ancient way of mining was to
*"The Study of the Rocks." By Frank Rutley, F.G.S. 1879.
(
+ See "The Geological Influences which have effected British History." By Archibald Geikie,
F.R.S. "Macmillan," No. 269, March, 1882. Consult also "Les Mouvements du Sol sur les Côtes
Occidentales de la France." By Alexandre Chèvremont.
CHAP. I.]
TIN IN THE SCILLY ISLANDS.
I I
search for metals in the same way as we at present raise stones out of
quarries, which, as the metals bear no proportion to the strata of stone in
which they lie, must have been very tedious and expensive. A little
farther we found a row of shallow tin-pits, none appearing to be more
than four fathoms deep, most of them no deeper than what the tinners
call costean shafts, which are only six or eight feet perpendicular: to the
west end of these pits there is the mouth of a drain or adit. This course
of tin bears east and west nearly, as our lodes, or tin veins, do in Cornwall.
These are the only tin-pits which we saw, or are anywhere to be seen, as we
were informed, in these islands."*
In another page Borlase says: "I saw one vein at Trescaw mentioned
before. It might be two feet wide, on a cliff near a place called the 'Gun-
well.' There was a narrow one on the same island under Oliver's Battery.
The former had been worked for tin, and has several shafts and burrows in
the course of it, the only ones in Scilly; the other we could perceive no metal
in." t
+
ور
This statement of the existence of tin in Scilly has been greatly strength-
ened by a precise statement of Whitaker, who asserts, in his "History of
Manchester": "In the month of May, 1767, a rich vein of tin was discovered
in St. Mary's, I think, which bore directly into the sea and pointed towards
the shore of Cornwall." It must not be forgotten that Borlase was for
twenty-four years the vicar of the mining parish of St. Just, and that
Whitaker was resident rector of Ruan Lanyhorne twelve years after the
date named in his book. It would be rash, therefore, to pronounce dogmati-
cally that tin had not been found in Scilly, in the face of such statements, but
certain it is, that the quantity of that metal obtained from these islands.
must have been exceedingly small. Cooley gets rid of the whole ques-
tion by saying, "The name Cassiterides is evidently but an epithet.'
Heath, in his "Islands of Scilly," states that the inhabitants "had mines of
tin and lead, which commodities they used to barter with merchants for earthen
vessels, salt, and instruments of brass." The same author again states,
'The lead was first brought from these islands into Greece by Madacritas."
This is the only mention made of lead, and, examining the geological condi-
tions of the islands, there are reasons for believing Heath to have been
deceived in this. He gives a rather long description of the methods of
working the tin streams and mines, but this applies more readily to the
mining works on the main land of Cornwall than to the islands of Scilly, §
Sir G. C. Lewis, endeavouring to support his views, quotes the Periplus
of Hanno, and the "Ora Maritima," by Avienus, in which is recorded the
discoveries of Himilco, giving them the date of about 470 B.C.
"The
report of Himilco was that the voyage from Gades to the Tin Islands (ie. to
Cornwall) occupied at least four months, and that the navigation in these
remote waters was impeded by the motionless air, by the abundance of
1
* “Observations on the Ancient and Present State of the Islands of Scilly, and their importance to
the Trade of Great Britain," p. 45. In a Letter to the Reverend Charles Lyttelton, LL.D., Dean of
Exeter and F.R.S. By William Borlase, M.A., F.R.S. (1756).
+ Ibid. p. 72.
"History of Maritime and Inland Discovery."
"A Natural and Historical Account of the Islands of Scilly, and a General Account of Cornwall."
By Robert Heath, an officer of his Majesty's service, some time in garrison at Scilly 1750.
12
[BOOK I.
HISTORICAL SKETCH.
seaweed, and by the monsters of the deep." After this quotation it is
not necessary to dwell any longer on the traditions and fables connected
with Scilly.
Nearly all the modern writers who have written on this subject are
disposed to regard the south-western promontory of Britain as the Cas-
siterides. In the imperfect state of the geography of those early days, the
configuration of the land of Cornwall was such, that, from the sea, it might
be readily mistaken for a group of islands. The Iktis of Diodorus-likely
to be St. Michael's Mount - being used as a port, from which tin was
shipped, became prominently marked as one of them. Diodorus speaks of
other islands, which were, according to the time of the tide, approachable
from the shore as peninsulas. There are several small insular masses
which, no doubt, at one time answered to this description. St. Nicholas's or
3
19
9
10
WEST HOE
16
15
12
13
6
12
10
7
10
13
9
15
8
14
13
(5
8
15
RAVENNESS POINT"
PRIDCE
3
3 4.
NICHOLAS OR
DRAKE'S ISLAND
13:
4
2
2
3
3
3
4
3
13/12/2
45
35
42
S
S
ล
45
Fig. 1.-The "Bridge" in Plymouth Sound.
Drake's Island, Plymouth Sound, is one of them. This is now separated
from Mount Edgecumbe by a ridge of rocks. The accompanying sketch
from the Admiralty Chart of Plymouth Sound, Fig. 1, shows the actual
soundings over the marked area known as the "Bridge," and beyond
it. Across the space supposed to have been the original connecting
link, it will be seen there is, between the exposed rocks on either
side, at low water, a depth of one fathom only, the greatest depth within
the marked area being 2 fathoms, while beyond it, on the northern
side, we obtain soundings of from 14 fathoms to 19 fathoms. It is
evident that the addition of but a small accumulation of soil, or rocky débris,
would render this "bridge" passable at low tides. Loo Island is another
example of the same kind. At very low water it was not unusual for men to
pass across the connecting ridge. There are also places, now peninsulas,
which were evidently at one period insular patches. "The Island" at
St. Ives was one of those: the narrow neck of detrital matter connecting
the island with the town is of comparatively recent formation. Pendennis
CHAP. I.]
THE SUBMERGENCE OF LAND.
13
Castle, at Falmouth, is probably another example of the same kind; and
others, smaller examples, but still giving evidence of man's labours upon
them, as the Chapel Rock at Perran-porth, might be named.
The following passages give the popular notion, as stated by nearly all
the older local historians, of the great changes which have led to the
submergence of the Mount's Bay *:-
"Of the time and manner of these catastrophes there is no record, a
circumstance remarkable, if, as supposed by some, they happened after
Christianity prevailed and monkish establishments were formed in this part
of Great Britain. All the historians of this county, from Leland, Norden,
and Carew, downward, have noticed the ancient tradition of St. Michael's
Mount being formerly situate in a wood several miles from the sea. They
have also handed down as a concurrent tradition, according to Carew, who,
treating of the ancient extent of the county, says: 'The encroaching sea
hath ravined from it the whole country of Lionnesse, together with divers
other parcels of no little circuit; and that such a Lionnesse was there, these
proofs are yet remaining. The space between the Land's End and the isles
of Scilly, being about thirty miles, to this day retaineth that name in Cornish,
Lethowsow, and carrieth an equal depth of forty or sixty fathoms (a thing not
usual in the sea's proper dominion), save that, about midway, there lieth a rock,
which at low water discovereth its head. They term it the 'Gulf' (now
known as the 'Wolf'), suiting thereby the other name of Scilla. Fishermen
also, casting their hooks thereabouts, have drawn up pieces of doors and
windows' (Carew, p. 3). To this Dr. Borlase (Letters on the Scilly Islands')
adds: 'That there existed formerly such a country as the Lionnesse, stretching
from the Land's End to the Scilly Islands, is much talked of in our parts.
Some fishermen also have insisted that, in the channel between the islands
of Scilly and the Land's End, there are to be seen tops of houses and other
remains of habitations.' Borlase, however, seemed desirous of showing
that he put no implicit faith in the story, by adding: 'But I produce these
arguments only as proofs of the tradition, and of the strong persuasion which
from time immemorial has prevailed among the inhabitants of Cornwall, that
such a country as Lionnesse once existed, but is now buried under the sea.'
Though it must be acknowledged that, two pages after, the venerable and
learned historian appears to credit the story, which then touched a string
that vibrated very powerfully on a favourite theory, viz. the rock idols and
rock sacrificial basins of the Druids."
It is possible that, either by the direct action of the ocean upon a low-
lying tract of land, which is supposed to have connected the islands of Scilly
with the main shore, or by the sinking of the land itself, the channel which
now rolls between the Land's End and the islands might have been formed.†
The conclusion to which I have arrived-after a most careful examination
* "Geological Transactions of Cornwall," vol. ii. Mr. Boase "On the Submersion of the Mount's
Bay."
† St. Michael's Mount. Mr. Jenkins, quoting Halse, says: "Contiguous to this parish or within
the jurisdiction thereof stands St. Michael's Mount, in the Kernawish tongue St. Mighele's Menyth, so
called for that the Britons, our ancestors, apprehended the appearance of the Archangel St. Michael about
the year of our Lord 495 to be on this place, though the Italians say it was upon Mount Garganus in their
country, and the Frenchmen tell us it was upon their Mount St. Michel in Normandy. About the time
of the appearance of this angel the Mount was called Dinsele or Dynsule, as appears from the history
of Llandaff church, which Mr. Camden, before me, hath well observed ('Camden Britannica,' p. 6.),
14
[BOOK I.
HISTORICAL SKETCH.
of the stanniferous regions of Cornwall, spread over many years—is that the
inhabitants, whether Belge or an aboriginal people, discovered in the
beds of rivers running through the valleys, and often subject to floods, a
remarkably heavy stone (oxide of tin, or black tin), which they found would
give them, by the action of fire, a beautifully white metal. Tradition says, the
Cornish first made fish-hooks and rings of this metal; but, be that as it may,
strangers, by some accident visiting their lands, discovered them in posses-
sion of a metal which, to them, was of the greatest value in the production of
an important alloy. It will be readily understood that the foreign traders
were anxious to discover the sources of this metal-tin-and that the natives
were especially desirous of preserving this a secret to themselves. The
result was, that the tin grounds were generally surrounded by extended earth-
works. An example of these still remains in the "Bolster," at St. Agnes, a
well-made earth mound, with a deep trench, which extends from Chapel Porth
to Trevaunance, a distance of two miles, completely enclosing the hill known
as the "Beacon," and the important tin district around it. We have, again,
at St. Ives the remains of a remarkable Cyclopean stonework, with here and
there indications of rude buildings, evidently places of defence, or store-
houses. This extends from near Tregenna to the rough promontory of
Clodgy. Other examples might be adduced of the value placed by the
natives on the produce of their "tin-streams" and shallow mines. In their
desire to secure themselves from their, probably, piratical customers, there is
no doubt they arranged that the traffic in tin should be confined to islands
near the shores. At St. Michael's Mount would be collected the tin produce
of all the district, from Marazion to St. Ives, and then to the Land's End,
and the fact of the sale of tin on this spot, to the Phoenicians, appears
preserved in the name of Market-Jew, which is commonly given to the
first-named town.
Thucydides has a passage, which seems to refer those insular tin-markets
to the desire of the Phoenicians, to secure for their own purposes, certain
convenient tracts for the shipment of their collected treasures.
"The
Phoenicians, likewise, had settlements all round the coasts of Sicily. They
secured the capes on the sea, and the small adjacent islands, for the purpose of
trafficking with the natives."* If they did so in Sicily, are they not likely to
have followed the same course in Cornwall?
Mr. John Hawkins, F.R.S., in writing "On the Changes which appear to have
taken place in the Primitive Form of the Cornish Peninsula," says, with special
reference to the Scilly Islands and the Mount's Bay: "Secondary changes
are the natural result of the present constitution of our atmosphere, and they
are consequently familiar to our notice. A changeable temperature, constant
humidity, the combined forces of wind and rain, the electric fluid, the action
of violent floods, even the silent force of vegetation, and, lastly, the heavy
swell and the boisterous surge of the Atlantic, have evidently wrought great
changes in the form of our peninsula. The naked summits of our moorstone
though he did not understand what those names imported, both being Kernawish, the first compounded
of Din-sile, Mass Sunday, the second, Din-sule, Mass Sabbath. I take it to signify The hill in open
view,' from 'sele,' a view or prospect."
* Thucydides, lib. vii.
ተ "Transactions of the Royal Geological Society of Cornwall," vol. iii. 1829.
"
CHAP. I.]
STANNIFEROUS REGIONS OF CORNWALL.
•
15
hills bear witness to the influence of the causes here enumerated; nor can
the solid rampart of rocks which is opposed to the western ocean wholly
resist the constant impulse of its waves. In length of time, the cliffs
so exposed to the fury of the waves are undermined, and not unfrequently im-
mense masses of rock are detached by their own weight from the higher levels.
The long reaches of rocks which are exposed at low water mark the extent
of these depredations, and the rocky islets which range along the coast must
be regarded as the wrecks of some advanced portion of high land. Even
the Mount, that noble ornament of our coast, must be placed by the geologist
in this class of phenomena." I have preferred to quote so good an authority
as Mr. J. Hawkins on this subject, explaining, as his words do, the forma-
tion of the "Bridge" in Plymouth Sound and other similar phenomena,
which will be further noticed when we come to consider the mineral
deposits. It should, however, be noted here that a regular survey of the
date of Edward IV. is often ap-
pealed to, to show that the
county of Cornwall contained
then twice the number of acres
that are now found in it.
2.-Bronze Image found in St. Just.
It will naturally be sup-
posed that the Phoenicians, if
they held possession of any
part of Cornwall, would have
left memorials of their pre-
sence. These are, however,
exceedingly rare. In the
Museum of the Royal Insti-
tution of Cornwall, at Truro,
is a small bronze casting of a
bull, about two inches in
height, which has many of the distinguishing features of the Assyrian
bronzes, Fig. 2. This was found in St. Just. A similar figure has been found
in Babylon.* Mr. R. S. Poole observes, "It is precisely what a Phoenician
trader would have carried; an idol common no doubt to Egypt and Pho-
nicia." Mr. Allen, in his history of Liskeard, informs, us that, in 1853, a
curious image, about two feet high, made of tin, and representing a man, was
found nine feet beneath the ground in a “Jew's house," or stream-work, in
Lanlivery parish. It weighed 9 lbs., and had some Hebrew initials on it.
Bronze instruments usually termed celts, rings of the same metal formed
to go round the wrists, together with swords of a peculiar construction, have
been found in the alluvial deposits and in peat-bogs, of Cornwall. It may
be thought by many that those belonged to the Romans; but Professor
Rawlinson says, "The bronze swords, daggers, and spear-heads, which have
neither a Greek nor a Roman type, were probably first introduced by the
Phoenician trade."‡
* Waring's "Monuments, &c., of a Remote Age." London, 1870. Pl. cvii. p. 84.
+ "Report and Journal of the Royal Institution of Cornwall."
Rawlinson's "Herodotus," edit. 1862, p. 417.
16
[BOOK I,
HISTORICAL SKETCH.
Mr. W. C. Borlase writes: "Spear-heads have occurred in St. Hilary and
St. Erth, and in the stream-works of Pentewan and Roach. Celts have occurred
near St. Michael's Mount; in St. Hilary, at Godolphin mine, and in the
stream-works of Treloy, Carnon-Leat, and elsewhere. We may add a bronze
fibula and an object of jet from Pentewan, a bronze pin with a leaden head
from St. Colomb, and a bronze and amber implement from Fowey, all in
connection with mining operations."*
A remarkable discovery was made at the mouth of the stream which forms
the western boundary of the town of Marazion. It is thus described by
Mr. Richard Edmonds.† "In 1849 the stream, having been diverted, flowed
westward along the base of the adjoining sand hillock, undermining and
washing away large portions, In sections thus made, I saw, at the depth of
between three and six yards beneath the surface, the remains of ancient
walls, rudely built of unhewn stones, with clay, and near them great
quantities of ashes, charcoal, and slag, besides some ancient broken pottery
of very rude manufacture, and much brick. In removing a portion of the
sand within a few inches of one of the walls, my nephew (Frederic Bernard
Edmonds) and myself, discovered two fragments of a bronze vessel resting on
charcoal, a considerable portion of which had combined with the copper
during the lapse of ages, and a beautiful green substance had resulted-the
carbonate of copper. The fragments were each about six inches long, four
wide, and only the sixteenth of an inch thick, having been apparently parts
of the circular top of a vessel three feet in diameter, the mouth being bent
back into a horizontal rim three-quarters of an inch broad. No charcoal
was on the insides of the fragments, but their outsides were completely
blackened and covered with it.
"Professor Hunt, at whose request I presented one of the fragments to the
Museum of Economic Geology, kindly analysed a small portion, the following
being the result :-
"Weight before analysis, 25 grains.
Copper
•
Tin.
Iron
Loss as carbonic acid and oxygen, the copper being partially in the state of carbonate,
and much of the tin in oxide
Earthy matter.
Grains.
18.0
2.25
1.0
3.0
0.75
25°
"These very ancient ruins, therefore, with the fragments of a bronze bowl,
and the abundance of ashes, charcoal, and slag, all covered with the sand of
many centuries, seem to indicate the very spot where, as Diodorus relates,
the tin was cast in cubic forms, previous to its conveyance in carts to the
neighbouring island during the recesses of the tide.
"The bronze vessel was, I conclude, brought hither by the Phoenicians,
for no copper was then raised in Cornwall; and Strabo mentions that the
Phoenicians furnished us with earthenware, salt, and copper or bronze
* “Historical Sketch of the Tin Trade in Cornwall, from the earliest Period to the present Day.” By
W. C. Borlase. Plymouth: 1874.
"The Land's End District: its Antiquities, Natural History," &c. By Richard Edmonds. 1862.
CHAP. I.]
ANCIENT SMELTING WORKS.
17
utensils (xaλkwμara*), in exchange for our tin, lead, and hides. We also learn
from Cæsar that the copper or bronze used by the Britons was imported ('ære
utuntur importato '†).
+
"It will be interesting now to inquire for what particular purpose this
very ancient bronze furnace was used. It appears that the tin underwent two
distinct fusions-first, for purification; secondly, for being cast into the form
of cubes; and for this latter purpose the bronze furnace may have been used
by the merchants after they had purchased the metal, the fire in this process
being applied exclusively to the exterior of the vessel; whereas the method
of smelting for purification by the native miners was, according to Pryce,
'to dig a hole in the ground and throw the tin ore on a charcoal fire, which
probably was excited by a bellows.' Many such rude pits, containing
smelted tin, have been discovered in this district, and are called 'Jews'
Houses,' there being a tradition that our tin mines were, in very remote
periods, 'wrought by the Jews with pickaxes of holm, box, and hartshorn,'
tools frequently found amongst the rubble of such works.' But as soon as
the natives had acquired the art of mining, the Jews may have purchased the
smelted metal from them, and, after having cast it into forms most convenient
for exportation, conveyed it to the Mount. Here, it is worthy of remark,
that the two different fusions to which the tin was then subjected in the most
ancient times-the one for purification, the other for being cast into particular
forms for exportation-are continued to the present day, and not only so, but
the different methods of conducting the processes are the same now as they
were at first, so far, at least, as that the metal is in contact with the fire in the
purifying or smelting process, and not so in the other. Both processes may
be seen in operation at Messrs. Bolitho's smelting-house and melting-house,
at Chyandour, adjoining Penzance, and the diameter of the iron furnace
employed in the latter house is very nearly the same as was that of the
bronze vessel of which the fragments have been described."
This bronze vessel was an interesting discovery in connection with
evidently an ancient smelting establishment, similar indeed to many others,
known as "Jews' Houses" in various parts of Cornwall. It is probable that
this vessel was introduced by the Phoenicians or the Jews; but it is not at all
likely that it was ever used for smelting tin. Mr. R. Edmonds was not
a metallurgical chemist, or he would have known that the smelting of
tin, in a vessel containing copper in its composition, would soon have been
fatal to the vessel. It had been used, no doubt, by the people who worked
the tin on this spot, as a vessel in which meat was soddened, or fish or
vegetables boiled; but it could not have been employed as a metallurgical
furnace.
Within the last thirty years, attention having been directed to the archæo-
logy of Cornwall, numerous excavations have been made which have been
rewarded by curious discoveries. Mr. W. C. Borlase, to whom we are
indebted for much information on this interesting subject, writes: "Amongst
the British huts' and 'old men's dwellings,' as the country people call
* Strabo's "Geography," lib. iii. s. 8. See Ezra viii. 27, and Ezekiel xxvii. 1.
+"De Bello Gallico," lib. v. s. 10.
"Mineralogia Cornubiensis," p. 281.
C
18
[BOOK I.
HISTORICAL SKETCH.
them in the West of England, much has been done to restore to us a lost
chapter in history. Buried beneath the ruins of these curious structures
indications of smelting, such as stone drains and pits containing fused tin,
have been brought to light."* In immediate connection with those ancient
dwellings, and in close proximity to the stream works in the valleys, and on
the widespread moors, on which detrital tin is discovered, rude furnaces are
not unfrequently found; and the tools which were employed by the ancient
smelters, and blocks of tin in the rude moulds of earth in which the metal
was cast. These are always called "Jews' houses," and the slabs of tin
"Jews' tin." It is therefore interesting to examine who those Jews were.
The hasty sketch which has been given will sufficiently establish the tradi-
tion that the Phoenicians-sailing principally from Sidon and from Tyre—
discovered the British Isles, that they found the natives already acquainted
with the metal, tin, and that they opened a trade with them. There appears
to be good evidence that these strangers were for some time kept to the
sea shores, and that the Cornish miners took considerable pains to protect
their tin grounds. But there is sufficient evidence to prove that eventually
a friendly intercourse was established, and that some of the strangers settled
permanently in the county of Cornwall. Mr. W. C. Borlase, whose studies
have been extensive, says :-
"The Phoenicians were, as we know, a genuine part and parcel of that
ancient Semitic, or, perhaps, Caucaso-Semitic race, who at a date which it is
difficult to fix, were partially displaced by a kindred tribe more skilled in the
art of war, on the banks of the Jordan. They were none other than the true
sons of Canaan."
Mr. R. S. Poole † says of them: "In religion and manners there is
an absolute identity between the Phoenicians and the Canaanites. Both
were worshippers of Baal and Ashtoreth, both practised the same cruel
rites."
It will be evident from what has been previously said, that the Phoenicians
were not Jews. They were a far more enterprising people, and they were a
maritime race, which the Jews never were. The peculiar characteristics of
the Phoenicians may have led to their being called Jews, or, the enterprising
merchants from Tyre and Sidon may have brought over Jews, as slaves or
criminals, to work in the Cornish mines. Joel indeed, B.C. 800, complains
on behalf of the Hebrews: "Because ye have taken away my silver and my
gold, and have carried into your temples my goodly pleasant things. The
children also of Judah and the children of Jerusalem, have ye sold unto the
Grecians."
The conclusion to which this examination leads us is, that many centuries
before the Christian era, a trade had been established between the natives
of Western Britain and Eastern Europe, in the metal tin, the ore of which
was obtained by the miners, chiefly from the detrital deposits, and smelted
by them in rude blast furnaces, and cast into irregular slabs of various sizes.
A block of tin was dredged up in Falmouth Harbour in the year 1823, now
preserved in the Museum of the Royal Institution at Truro, which is far
* "Historical Sketch of the Tin Trade in Cornwall." By William Copeland Borlase. 1874.
† “Journal of the Royal Institution of Cornwall.”
CHAP. I.]
METALLURGIES OTHER THAN TIN.
19
more regular in form than any other example known. This block of tin is
supposed to correspond with the description given by Diodorus Siculus,
who says: "They form it into shapes like knuckle bones!" Sir Henry
James, with some ingenuity, in a paper written for the Royal Institution of
Cornwall, says: "It is impossible to look at this block of tin and see how
admirably it is designed for transport both by land and water, without
arriving at the conclusion that we have here before us one of the 'astragali'
described by Diodorus." The writer proceeds to show how the shape and
size of the block of tin (it weighs 120 lbs.) peculiarly fitted it for the bottom
of a boat, or the side of a pack-saddle. It unfortunately happens that this is
the only example of a well-shaped slab which has ever been discovered. It
conveys to the mind of the observer the idea of its being the production of a
people far more advanced than the ancient Cornish miners were.
Objections have been raised to the Phoenician intercourse in the allega-
tion that the tin trade was carried on overland through Gaul to Marseilles.
There is no doubt that such a trade was established, but that was at a later
period. Cæsar, in his "Wars," speaks of the merchants who inhabit the
coasts of Gaul, and resort to Britain for trade. Strabo, indeed, says:
"Formerly the Phoenicians alone carried on this traffic from Gades." There
is but small information to be gleaned, either from tradition or history,
as to any other metals being known to the ancients, as the products of
Britain.
LEAD has been named by Pliny, but it is not easy to separate his “white
lead" and his "black lead" from each other. It is highly probable they
were but tin in different states. It is difficult to suppose that such a mineral
as galena-sulphide of lead-existing as it does in many parts of Cornwall,
and showing itself in lodes at or near the surface, should not have been
detected. We have no evidence, however, to prove that it was ever worked
previous to the Roman invasion.
COPPER was never an article of trade with the merchants who came for
tin to Britain, and probably its ores were not recognised by the early
miners of this country. It is, however, evident that brass was largely used in
the East at a very early period of the world's history, and we know from the
analyses which have been made of metallic weapons-tools and ornaments-
recovered from the ruins of Nineveh, Babylon, and Egypt, that bronze was
very commonly employed in the ancient empires of the East. The probability
is that the copper for this alloy was obtained from the mountains of Arabia,
where there are existing evidences of extensive mining operations of a very
early date. Again, there is not much doubt but that the island of Cyprus
was in those days largely worked for the copper ore which its rocks were
known to contain.
All the tin taken from Cornwall by the Phoenicians was obtained from
the deposits which had been for ages accumulating in the valleys and in the
beds of rivers. This débris was derived from the wearing down of the granite
hills, which were interpenetrated with stanniferous veins. But we find very
few examples of copper lodes coming to the surface. In nearly all cases this
ore was discovered only after the miners began to penetrate the earth.
Consequently the copper lodes would escape the wearing action to which tin
C 2
20
[BOOK I.
HISTORICAL SKETCH.
was exposed, and the ore of copper was rarely, if ever, discovered in the
stream deposits.
GOLD has always been found in small quantities in the "tin streams,"
and collected by the "streamers," as the men working over the alluvial
deposits are called. Cæsar, in his Commentaries, accuses the Britons of
having assisted the Gauls with their treasures. It is not improbable that in
the first working over the alluvial deposits containing tin, gold, in some
quantities, may have been found.
The tin-streamers formerly, always carried quills in their pockets, and in
these they preserved the minute particles of gold which they picked out
from amongst the grains of black tin after the earthy matter had been
washed away. This appears to have been a custom derived from a remote
antiquity.
When we consider the care with which the detrital matter containing tin
has been washed over, and the long period of time to which it has been sub-
jected to "streaming" operations, we must feel convinced that at one period
those deposits must have been much more auriferous than they have been in
recent years.
Samuel Rush Meyrick* speculates on the probability that the Britons
wrought the Cardiganshire mines for gold, and he infers this chiefly from the
Triad which celebrates Cas-wallan, Manawydan, and Llew Llawgyfes, as
three chiefs distinguished by the possession of golden cars. Cymbeline,
Prince of the Trinobantes, so tradition informs us, worked a gold mine in
Essex. That gold was found at a very early period in several parts of the
United Kingdom is rendered more and more probable, by the discovery of
gold ornaments in very ancient graves; but there is no reliable information
of any kind prior to the Roman occupation.
IRON was discovered as an ore, and must have been often reduced to
a metallic state. We find this metal used in thin sheets to protect the
edges of wooden shovels, which, as they have been found in connection
with ancient tin works, were no doubt used in digging the alluvial deposits;
and we have also found iron implements.
We may conclude this chapter with a quotation from a well-known and
highly appreciated modern writer. †
"It was from Gades, as a centre, that these enterprising traders (the
Phoenicians), pushing their coasting voyages yet farther, established relations
with the tin miners of Cornwall. . . . It requires some effort to carry back
our imagination to the time when, along all this vast length of country, from
Tyre and Sidon to the coast of Cornwall, there was no merchant ship to buy
or sell goods except those of the Phoenicians.. The rudest tribes find
advantage in such visitors; and we cannot doubt that the men whose
resolute love of gain braved so many hazards and difficulties, must have
been rewarded with profits on the largest scale of monopoly."
*
"The History and Antiquities of the County of Cardiganshire." 1810.
† Grote's "History of Greece," vol. iii. p. 370.
CHAPTER II.
MINING DURING THE ROMAN OCCUPATION.
LEAD, ETC.-On or about the 26th of August, fifty-five years before the
birth of Christ, Julius Cæsar landed in Britain.* The questions have been
asked, What was the motive by which Cæsar was urged to attempt the con-
quest of these islands? What were the inducements to the Romans to hold
possession of these islands for five centuries? Cæsar himself writes: "The
island is well peopled, full of houses, built after the manner of the Gauls,
and abounds in cattle. They use brass money and iron rings of a certain
weight. The provinces remote from the sea produce tin,† and those upon the
coast iron, but the latter in no great quantity. Their brass is all imported."
The Roman people were averse to this enterprise, considering it hazardous
and not likely to be profitable. Cicero, in one of his epistles to Atticus, writes:
"The event of the British war is awaited with impatience. It is certain that
all the approaches to this island are fortified by amazing outworks; and it
is universally known, that a scruple of silver is not to be found in the whole
island."
We have an example in this, of the difficulty of gaining reliable informa-
tion, on any question connected with the prejudices of party in ancient time,
as well as in our modern days. There is no doubt but that Cæsar represented
to his countrymen that Britain would be an important acquisition; while
Cicero, in absolute ignorance of the real condition of things, gives a state-
ment which has no foundation in truth, he being actuated by the desire to
raise a cry against the growing power and popularity of Julius Cæsar.
We may judge of the general idea prevailing, at the time of Cæsar's
invasion, by the following quotation from Pliny,‡ who wrote A.D. 79.
"The nature of lead comes next to be considered " (Pliny was evidently
in ignorance of the difference in the metals lead and tin). "There are two
kinds of it, the white and the black. The white is the most valuable, it was
called by the Greeks cassiteros (that is tin), and there is a fabulous story told
of their going in quest of it to the islands of the Atlantic, and of its being
brought in barks made of osiers and covered with hides. It is now known
that it is the production of Lusitania and Gallæcia. It is a sand found on
the surface of the earth, and of a black colour, and is only to be detected by
its weight. It is mingled with small pebbles, particularly in the dried beds
of rivers. The miners wash this sand and calcine the deposit in the furnace.
* See "History of Julius Cæsar," by Napoleon III., vol. ii. pp. 210-215.
"Wars," v. 12. Cæsar must have been deceived by the term plumbum album-used by some
authors for tin-plumbum nigrum being lead.
‡ Pliny's "Natural History," book xxxiv. chaps. 47-49.
22
[BOOK I.
HISTORICAL SKETCH.
It is also found in the gold mines that are known as alutia; the stream of
water which is passed through them detaching certain black pebbles mottled
with small white spots, and of the same weight as gold. Hence it is that
they remain with the gold in the baskets in which it is collected; and being
separated in the furnace, are then melted, and become converted into white
lead (ie. white tin)."
Pliny's description of the mode of occurrence, and the system of working,
is correct; but he errs in speaking of the separation of the gold. The gold
and the tin ore (oxide of tin-black tin) being of nearly the same specific
gravity, are left behind together, when the lighter earthy matters are washed
away, and from the earliest recorded time the miners have picked out the
particles of gold and preserved them.
“Black lead,” Pliny continues, "is not procured in Gallæcia, although
it so greatly abounds in the neighbouring province of Cantabria; nor is
silver procured from white lead, although it is from black." This black lead
is the ordinary galena-sulphide of lead-which generally contains some
silver. "There are two different sources of black lead, it being procured
either from its native ore, where it is produced without any intermixture
of any other substance, or else from an ore which contains it in common
with silver, the two metals being fused together." Again: "Black lead is
used in the form of pipes and sheets. It is extracted with great labour in
Spain, and throughout the Gallic provinces. But in Britannia it is found in
the upper stratum of the earth in such abundance that a law has been
spontaneously made, prohibiting any one from working more than a certain
quantity of it."
These quotations render it evident that Julius Cæsar was led to the inva-
sion of Britain through a belief in the metalliferous value of its rocks. It is,
however, clear that Cæsar himself had no correct knowledge of the subject,
since he says, "The provinces remote from the sea produce tin;" the
production of tin in these islands being confined to Cornwall and Devonshire,
which are especially sea-washed counties.
A half century passed away from the time of Cæsar's landing to the
writing of Diodorus the Sicilian. British tin in the interval had been
conveyed across Gaul to the mouth of the Rhone. The great port of Tyre
had fallen, Carthage had perished, Cadez was a Roman port, and all Spain
a Roman province.
Cæsar and Diodorus both describe the conquest of a town, Alesia (Arras),
built on a hill in a very strong position, about fifty miles from the coast, and
nearly midway between Boulogne and Dieppe, the people of which were
said to have invented the art of fining articles of metal, and plating with
silver. Pliny says: "It was in the Gallic provinces that the method was
discovered of coating articles of copper with white lead (tin), so as to be
scarcely distinguished from silver; articles thus plated are known as incoe-
tilia. At a later period the people of the town of Alesia began to use a
similar process for plating articles with silver."+
* "De Bello Gallico," book xvii. chap. 79.
+ Literally inboiled, or coated by immersion in the melted tin.
Pliny's "Natural History," book xxxiv. chap. 48.
CHAP. II.]
ROMAN MINING IN CORNWALL.
23
In the days of Augustus Cæsar, when tranquillity prevailed, we might
expect to find evidences of the presence of the Romans in the mining districts
of the west.
Nordan,* indeed, says the Romans "took their turn to work for tin, as is
supposed, by certain of their money found in some old works renewed.”
There are existing evidences of the Romans having penetrated into Cornwall,
and there are but a few examples of Roman engineering in the mines. The
most remarkable existed, not many years since, in an extensive working for
tin, in the mine called Baldue,† in the parish of Kea. An open working, or
chasm, extended for a considerable distance on the hill. The miners dis-
covering a tin lode, had followed it, and worked down upon it until the
accumulation of water prevented their going any deeper, and it is presumed
the work was abandoned. Subsequently the attention of some miners
possessing more engineering skill was drawn to this place. These men
went to the bottom of the hill and drove in a level at right angles to the old
workings on the lode, so as to cut it at a lower depth and thus form a
channel by which the water might be drained off. The peculiarity of this
adit or level was, the perfection of the arch formed, and the good masonry of
squared stones of which it was constructed. This appears to point to Roman
miners. In the parish of Kea remains, thought to be Roman, have been
found. Hals, in his "History of Cornwall," says: "In this place of Guddarne,
in my youth, I was showed by Mr. Bauden, a brass, or iron crock, containing
about eight gallons, wherein, as he said, his father . . . . found so vast a
quantity of gold and silver, as not only advanced him from the rank of a
rack-renter to that of a freeholder, but from the distinction of a plebeian to
that of a gentleman." In St. Levan, in Paul, in Ludgvan, and in Towed-
nach, Roman coins, brass and silver, have been found; amongst them coins
of Claudius, Adrian, Neva, Domitian, Antoninus, Pius, and others. In drain-
ing the marsh near Marazion, an earthen pot was discovered containing
a thousand copper coins of the emperors who lived between the years 260
and 350.§
A Roman camp was opened out in a field half a mile north-east of
Relubbus, near Leeds Town, Cornwall. Its length was fifty yards, and
its breadth forty-five yards. Within the enclosure was a well, in which were
two Roman vases, or patera, made of tin, the pateræ having rudely engraved
in Greek and Roman letters, an inscription which Dr. Borlase reads thus-
Livius Modestus Driuli filius Deo Marti.||
In 1825, when removing part of the cliff to make the causeway across the
estuary of Hayle, a vessel of pure copper was found, containing small coins
of very rude manufacture. Mr. Joseph Carne ¶ thinks these were coined by
the Romans, near the supposed Roman camp, discovered in the estate of
Bosense, about two miles from Hayle. It is stated that at Godolphin, in
1779, an urn filled with Roman copper coins was dug up.
*Speculi Britanniæ pars," p. 12.
The Black Work-a mile from Chacewater.
"The Parochial History of Cornwall," vol. ii. p. 300. By Davies Gilbert, F.R.S., sometime
President of the Royal Society.
1769.
"The Land's End District," by Richard Edmonds, and Drew's "Cornwall."
These were deposited in the Ashmolean Museum, at Oxford-Borlase's "Antiquities," 2nd edition,
¶ "Transactions of the Royal Geological Society of Cornwall."
24
[BOOK I.
HISTORICAL SKETCH.
St. Hilary Church, about five miles from Penzance, formerly had some
Roman inscribed stones, which were destroyed by a fire in 1853. One has
been partly preserved, and is inscribed to Flavius Julius Constantine, who
was declared Cæsar A.D. 317, and received from his father, Gaul, Spain, and
Britain, as his portion of the empire, A.D. 337.
It is quite true, to say, that there are but slight evidences existing of any
active operations having been carried on by the Romans themselves in
Cornwall during the period of their occupation. It must not be supposed that
the Romans worked any of the British mines. Whether they desired to
obtain tin, or copper, or lead, they used their slaves as their miners. In the
A
Fig. 3.-Chysoister Hut.
"Life of Agricola," by Tacitus, a
speech is attributed to the British
leader, Galgacus, in which servitude
in the mines is especially named as
the consequence of defeat-"Ibi tri-
buta, et mettala, et ceteræ servientium.
pena." This servitude, as we learn
from Diodorus, was dreadfully severe.
Professor John Phillips states-he
does not give his authority-“There
is sufficient reason to believe that the
Emperor had Roman soldiers sta-
tioned at the mines of Cornwall to
superintend the working and to trans-
port the tin to the seat of the Empire."
A few inscribed stones mark the
burial-places of some Roman settlers.
Bronze celts, rings, brooches, and
Roman coins have been found; and
some evidence has recently been ob-
tained, mainly by the investigation's
of Mr. W. C. Borlase, who has furnished a large amount of most curious
information—the result of his industrious examination of the ancient mining
districts-and especially drawn attention to the cave dwellings of the
aboriginal people. One of these, the Chysoister Hut, is represented (Fig. 3),
and at the spot marked A a mass of fused tin was found, and other indica-
tions of the rude smelting processes carried on by those primitive metallurgists.
"In addition to the ashes of wood and peat gathered around the
rude furnaces, and to the slags rejected by those early smelters, some of
them containing masses of the easily fused metal bismuth, we discover,”
says Mr. W. C. Borlase, “side by side with these, and evidently
belonging to a contemporaneous occupation of the places, objects such
as iron implements for warfare and domestic use, pottery, Samian ware,
and coins, clearly assignable to the age of the Roman-Britons. Hence,
then, we may infer, since some of the coins are as late as the close of
the third century, that Rome was still maintaining a commercial rela-
tionship with the tin-producing district of her ferox provincia, down to a
period not long prior to that of her final withdrawal from the island.
•
CHAP. 11.]
6
ROMAN MINING IN WALES.
25
That these commercial relations were of no inconsiderable extent and
importance, we may further judge from the very frequent occurrence of
these villages and cave dwellings; while, from the similarity of their con-
struction, and the identity of the objects exhumed from their floors, we may
be sure that they were all the work of one and the same people at a definite
epoch in their progressive culture. We have, therefore, in them internal
evidence of mining industry at a time when written history is silent. It is
the pickaxe and the shovel which have opened the mouth of these dumb
ruins, and make them tell us, in language which, as Mr. Freeman has said,
can neither err nor lie, however we may misinterpret it,' the story of bygone
commercial prosperity in an age where all besides is dark. The date of the
abandonment of these settlements it would be difficult to fix. Whether or
not some few of them lingered on into the troublous times succeeding the
desertion of Britain by the Roman arms, or whether they were dismantled
at that time, it is impossible to say. The occurrence of villages precisely
similar in every respect to these, in the mining districts of Carnarvonshire,
may possibly point to the migration thither of Cornish miners when, owing
to the cessation of the Roman traffic, work was slack at home. We cannot
pass from the Romans in Britain without observing that it can be scarcely
doubted that their sojourn here, and the civilising influences which accom-
panied it, contributed greatly to the welfare and development of the tin
mines. How far such an influence may have been at work to establish those
rules and regulations under which the stannaries were worked, and which
reappear as ancient customs' under the Anglo-Norman kings, it is hard
to say.
"'*
The obscure history of the Romans, in the century following immediately
upon their taking possession of Britain, furnishes really no information as to
their mining operations. We learn that, after a short campaign under
Claudius, about A.D. 43 or 44, all their available forces were marched to the
borders of Wales. Ostorius Scapula was sent a few years later to take
command in this distant province, and, having organised his troops, he
marched into the country of the Cangi, who evidently inhabited the northern
coasts of Wales. In A.D. 61, Suetonius Paulinus attacked the Britons in the
island of Anglesea, and reduced this turbulent body to peace. Those facts
point to some especial cause as leading the Roman arms to this very remote
territory. Without doubt it was the hope of the discovery of the reputed vast
mineral treasures of North Wales and Anglesea which led to the desire to
bring the Welshmen into subjection to Rome. In 1783 a Roman pig of lead
was found in Hampshire, near Broughton Brook, Stockbridge, bearing the
inscription, NERONIS. AUG. EX. KIAN. IIII. COS. BRIT, intimating
that this lead was taken from the mines of the Kiangi, or Cangi, in the
fourth consulate of the Emperor Nero, which begins in the year 60. In
letters on the side of this pig of lead are-EX ARGENT.
These are
supposed to signify that the lead has been deprived of its silver. Ex
argentate, which, in its abbreviated form, is frequently found on Roman pig
lead, clearly mark it as refined or desilverised lead. The separation of
silver from lead and baser matters was understood at a very early period in
*“Historical Sketch of the Tin Trade in Cornwall." By William Copeland Borlase.
26
[BOOK I.
HISTORICAL SKETCH.
man's history. In Psalm xii. v. 6, we read: "Silver is tried in a furnace
of earth, and purified seven times." Again, in Psalm lvi. v. 6: "Thou hast
tried us as silver is tried." In Proverbs xvii. v. 3, we are informed, "The
fining-pot is for the silver;" and in chap. xxv. v. 4 of the same book the
result of refining is thus described: "Take away the dross from the silver,
and there shall come forth a vessel for the finer." In Ezekiel xxii. v. 20, we
read: "The house of Israel is to me become dross: all they are brass, and
tin, and iron, and lead in the midst of the furnace: they are even the dross
of silver." We learn from these repeated references to the separation of
silver from lead, which are found in the Bible, that the ancients had
acquired a satisfactory knowledge of one of the most difficult processes of
metallurgy. We can therefore readily understand that the Romans came
to this country prepared to use their knowledge in the most effective
manner—in the metallurgy of lead—and they have left us numerous
examples of the truth of this, a few of which are the following.
In NORTHUMBERLAND and. CUMBERLAND evidences of very ancient
mining have been found. In Allendale and Alston Moor large masses of old
scoria-no doubt Roman-have been discovered, and in many cases these
slags have been rich enough in lead, to pay for its reduction. Dr. Bruce, in
his "Roman Wall," thus describes a Roman furnace discovered in the neigh-
bourhood of Lanchester: "The method adopted by the Romans of producing
the blast necessary to smelt the metal was made apparent. Two tunnels
had been formed in the side of the hill-they were wide at one extremity,
but tapered off to a narrow bore at the other, where they met in a point.
The mouths of the channels opened towards the west, from which quarter a
prevalent wind blows in this valley, and sometimes with great violence. The
blast received by them would, when the wind was high, be poured with con-
siderable force and effect upon the smelting furnaces at the extremity of
the tunnels.”* This may apply equally to a furnace for smelting lead or
iron.
In YORKSHIRE many evidences of Roman lead mines have been discovered.
The lead mines of Greenhow Hill, near Pateley Bridge, are remarkable
examples. In 1734, two Roman pigs of lead were found at Hayshaw Bank,
near Dacre Pasture. One of them was presented to the British Museum by
the executors of Sir William Ingilby, Bart., in 1772. It bears the inscription,
IMP. CAS. DOMITIANO. AVG. COS. VII., or, Imperatore Cæsare
Domitiano Augusto Consule Septimum. In the year A.D. 81, Domitian was
elected consul for the seventh time.†
In DERBYSHIRE the Romans must have mined extensively for lead, pro-
bably employing their slaves in the work. Waste-heaps, containing galena,
are found in all parts of the county, the sulphide of lead being, in most
cases, partially converted into a carbonate. The modern smelters of lead
in Derbyshire have, for a long period, been obtaining lead from the slimes and
slags discovered upon the sites of old Roman works. Several pigs of lead
with Latin inscriptions have been found, and many of them are still preserved.
* "The Roman Wall: an historical and topographical Description of the Barrier of the lower
Isthmus extending from the Tyne to the Solway," p. 432. By Dr. Bruce. 1852.
↑ Ward's "Considerations on a Draught of two large Pieces of Lead, with Roman Inscriptions upon
them, found in Yorkshire." ("Phil. Trans." vol. xlix. p. 694.)
CHAP. II.]
ROMAN MINES IN SHROPSHIRE.
27
In NOTTINGHAMSHIRE, at Hexgrave Park, near Southwell, in 1848, a pig
weighing 184 lbs. was ploughed up, a cast from which is in the Museum of
Practical Geology. In that museum will also be found a cast from another
pig of lead, found on Hints Common, near Watling Street, in STAFFORD-
SHIRE.
In CHESHIRE several pieces of Roman lead have been found, and are
preserved in the museums of the county.
SHROPSHIRE, especially in the Shelve district, exhibits remarkable
examples of Roman mining. Mr. Thomas Wright, the well-known antiquary,
thus describes the Roman mines: "Two or three veins had cropt out almost
parallel to each other, and the Roman miners actually cut the mountain from
top to bottom, into great ridges or grooves. We might suppose from the
appearance that they began at the bottom, and then, after they had followed
the metal in one spot as far as they could, they commenced immediately
above, and filled up the previous excavation with the waste from the new
one. As we approach the top of the hill the remains of these excavations.
take the form of vast caverns, which have evidently gone to a great depth,
but the entrance has been clogged up with fallen rock.” * Most of the
modern lead mines in the Shelve district belong to Mr. More, of Linley Hall,
and several of those very ancient mines are still being worked for lead.
The Roman Gravels and the White Grit mine are striking examples. In
the latter mine a pig of lead was found which bears the inscription, IMP .
HADRIANI. AVG., and several examples of the Roman miners' tools, which
are of a very rude description, have been from time to time discovered.
Early implements have also been found also candles used by the
Roman miners. At Clive, near Grinshill, and at the hill of Llanymynech,
Roman workings have been opened. A Mr. J. F. M. Dovaston explored these
workings a few years since. Some of the shafts or passages were extremely
sinuous, extending as much as two hundred yards. They were usually
from a yard to three yards wide, and occasionally developed into broad
and lofty chambers. The long passages frequently terminated in small
holes about the size to admit a man's arm, as if thin strips of metal had
been worked out. Twenty copper coins were found in those mines, ranging
from the earlier emperors to a late period of Roman sway.
Mr. T. Wright, in his paper on "Roman Mining Operations on the
Borders of Wales," enables us to draw up, with much correctness, a state-
ment of the general progress of this remarkable people in their search for
minerals in Britain. The quantities of iron slag and cinders found in the
border counties of Wales and England, and the Roman coins discovered
with them, prove that the Romans looked as carefully after iron ore, as they
did after lead.
We may trace the Romans from the wild country of the Forest of
Dean, and the beautiful Wye scenery in the south, through the hills of
Shropshire and Montgomeryshire, Cheshire, and the counties of Flint and
Denbigh, and through the ancient country of the Cangi, or Kiangi, up to
the shores of the Irish Channel.
In the turn of the river Wye, amid the beautiful scenery between the
* See Illustrated London News, October 4th, 1856, p. 351.
28
LBOOK I.
HISTORICAL SKETCH.
ruins of Goodrich Castle and Monmouth, rise two massive hills-the Great
and Little Dowards. These have been extensively mined by the Romans.
The entrances through caverns are still the objects of curiosity, and, although
now clogged up, they have been entered, and a succession of chambers
discovered, and rude galleries running in more than one direction. In the
Forest of Dean the Romans began their operations by sinking a large pit,
from twenty to thirty feet in diameter, and when at the bottom of this pit
they came upon a vein of ore they followed it. The Roman workings at
Raghleigh Cross, on the Brendon Hills, are of a similar character. These
pits, many of which are known, are popularly called scowles, the meaning of
which Mr. Wright has not been able to discover. The miners now living in
the neighbourhood state that these mines extend two or three hundred
feet underground, and that they have descended them with lanterns, and
generally found clear water at the bottom.* That they are Roman is proved
by the fact that Roman coins and pottery are found in and about the scowles.
The most important group of lead mines worked by the Romans is that of
the Stiperstones and its dependents, especially in the district which is
known as the Shelve Hill. In this hill the lead ore runs in almost hori-
zontal veins from east to west, turning occasionally a little towards the
north-west. This locality was, without doubt, the scene of some of the
earliest of the mining operations of the Romans. Many pigs of lead with
Roman inscriptions have been found in this district. "With these facts
before us," Mr. Wright remarks, "it is more than probable that it was
this locality of which Pliny wrote before A.D. 79 (when he died): 'Nigro
plumbum ad fistulas laminasque utimus, laboriosius in Hispania eruto
totasque per Gallias, sed in Britanni summo terræ corio adeo large, ut lex
dicatur ne plus certo modo fiat."" The ironworks of the Forest of Dean
are well known, and satisfactory evidence has been found of their being
built by early Roman settlers. Similar remains have been found in
Yorkshire and in Northumberland.
Pliny's description of the lead as found summo terræ corio-on the very
skin of the earth-is nearly true, for some eight or nine parallel lodes come
out upon the surface, and all these the Romans worked, beginning apparently
from the bottom of the hill, and following the vein into the rock as far as
they could trace it. To the north of Shelve, in the parish of Minsterley,
is the Snailbeach mine, which is supposed to have been extensively worked
by the Romans. The miners still speak of the upper part of it as the Roman
Level. Two or three miles distant the remains of a fine Roman villa have
been found in the parish of Pontesbury.
Westward of the Stiperstones Mountain, and through the county of MONT-
GOMERY, copper and lead are found. Roman mines have been discovered in
Newtown Park, and were reopened a few years ago; they were productive
in argentiferous galena, but poor for copper. The Romans appear care-
fully to have separated the silver from the lead. Many of the pigs of lead
found are inscribed-EX. ARG., or LVT. EX. ARG., or MET. LVT.EX.
* A full account of the Roman Iron Works in the Forest of Dean, and also of those in the Weald of
Kent and Sussex, will be found in the "Wanderings of an Antiquary," by Thomas Wright, published
in 1854.
+ Pliny's "Nat. Hist." lib. xxxiv. cap. 17.
CHAP. II.]
ANCIENT MINING TOOLS.
29
ARG.-signifying that the metal has been washed of the silver. It should be
remembered that long before the Roman period the processes of separating
and refining silver were well known and practised in the East.
About six miles from Newtown, on an elevation on the banks of the
Severn, are the remains of a rather important Roman station, called by the
Welsh Caer Sws, which was in all probability a mining town.
At the western extremity of Montgomery, in the park of Machynlleth, a
Roman mine was reopened in 1856, and produced copper and lead. The
tools found in the old working were certainly Roman.
To the east of the Stiperstones, copper is found, but not in such quantities
as to pay for the labour of mining. The hill in Linley Park contains copper,
and traces of that metal may be found over the whole district. All this
district has been, it is supposed, worked by the Romans. Old shafts and
adits have been discovered, and in them Roman remains.
Mr. Wright concludes his notice of Roman mining by the following
note: "When we consider the facility which nature gave to the ancients to
obtain the higher metals from the surface, and the length of time they no
doubt worked the mines, and the fact that we learn from ancient documents
that mines were worked here in the Middle Ages and at various more
recent times, and that during the last seventy years an increasingly large
supply has been raised, although not a fifth of the ground has been explored,
we may imagine the richness of this district (Shropshire) in ore. Imme-
diately under one part of the ancient workings, about fifteen years ago, one
pipe of ore produced two thousand tons in eleven months, at a depth of
eighty yards."
This consideration must press itself upon every thoughtful mind. The
quantity of ores of various descriptions worked and used by the Britons
and those who first came to this country, and worked for tin and gold by
the Romans during the five hundred years of their occupation, and by
the miners of the Middle Ages, must represent a most enormous quantity.
Yet we are still producing annually metals and minerals to the value of
more than £90,000,000 sterling.
In FLINTSHIRE-no doubt the country of the Cangi-the remains of Roman
lead mines are met with; and in the land to the west of Flint, lead scoriæ have
been met with, and Roman pigs of lead ready for exportation.
The Romans found copper in the Great Ormes Head, and worked it
extensively. In Llandudno, when digging for the foundations of buildings,
the modern excavators have come upon the soil of the Roman level, coloured
by the washings of the ore. In the neighbourhood of Caerhen, or Caerhun
-supposed to be the ancient Conovium-about five miles to the south of
Conway, there are also traces of very ancient mining.
Wooden spades have been found in the Roman mines which are remark-
able as having handles only just long enough to hold by. In some cases we
find that a longer staff was fitted into the hole in the centre of the spade,
which is bevelled backwards: this, being firmly lashed to the short handle,
was very secure and immovable. Those spades are usually of very hard oak,
roughly cleaved with a wedge-shaped tool, probably a bronze celt (see
Fig. 4), although from their roughness they may have been prepared with

30
HISTORICAL SKETCH.
[BOOK I.
flint tools. Another example of an ancient spade, in all probability Roman,
which was cleverly edged and cramped with iron, is shown in Fig. 5.
The shovel blade of oak is expressed by perpendicular lines. The
cramping and edging with iron is shown by the darker shading. This
Fig. 4.-Roman Spades.
shovel was found in the year 1760, in a stream-works in Parr-Moor, in
the parish of St. Ewe, Cornwall, about six feet under the surface. Part
TWAR
E
C
B
C
Fig. 5.-Shovel Blades.
3 4 5 6 7 8 9
10
12 13
ZAY
SCALE OF INCHES
Fig. 5.-A A represents the front of the shovel blade, which is concave. B B shows the back part
of the blade, which is convex; c is the hole for fastening to the side of the hilt; and D the hole of the
oak-pin, cramped with iron, for securing the hilt, marked E.
of the hilt was in the shovel when found, with the oak-pin whereby it was
fastened to the blade.
In, Carew's time [temp. Eliz.] Parr-Moor was so little frequented, that
among the ordinary tools of the tinners he reckoned "a broad shovel, the
utter part of iron, the middle of timber, into which the staffe is stopewise
fastened;"* showing that no improvements had reached that place.
* Carew's "Survey," par. 21.
CHAP. II.]
MINING ON THE MENDIPS.
31
SOMERSETSHIRE.-Upon the Mendip Hills, numerous examples of
Roman mining are to be found. At the Waldegrave mines, and at Charter-
house, immense deposits of slags and slimes have been most industriously
worked for many years, yielding enormous quantities of lead. This has
been brought forward as evidence that the Roman smelters were but ill-
acquainted with their trade. When we consider the rude character of their
furnaces, and the imperfect fuel with which they fed them, it will not be
thought surprising that lead is still left in the débris of their mines. The
Roman slags now found around Charterhouse contain from 20 per cent. to
25 per cent. of lead. Therefore the old smelters must have extracted from
about two-thirds to three-fourths of the lead from the ore. It has often been
remarked that the Mendip Hills exhibit but few marks comparatively truly
of Roman workings. A recent exploration of the Lamb Bottom Cavern at
Harptree offers probably an explanation.
D
C
·--110 ft-----
A
SCALE 160 FTTO INCH
Fig. 6.-Lamb Bottom Cavern.
ENTRANCE
In the year 1700 a Mr. Beaumont, who visited Harptree about 1660, de-
scribed this place.* "The most considerable of these vaults which I have
known on Mendip Hills is on the northerly part of them, in a hill called Lamb,
lying above the parish of Harptree. Much ore has been formerly raised on
this hill, and being told some years since that a very great vault had been
discovered, I took my miners with me and went to see it. First we de-
scended a perpendicular shaft about 10 fathoms, then we came into a leading
vault which extends itself in length about 40 fathoms: it runs, not upon a
level, but descending, so that when you come to the end of it you are 23
fathoms deep, by a perpendicular line. The floor of it is full of loose rocks;
its roof is finely vaulted with limestone rocks, having flowers of all colours
hanging from them, which present a most beautiful object to the eye, being
always kept moist by the distilling waters. In some parts the roof is about
* "Philosophical Transactions" for 1700, p. 369. See also Collinson's "History of Somersetshire ;"
Rutter's "Delineations of Somersetshire;" Buckland and Conybeare in "Transactions of the Geological
Society," in 1824; and Maton's "Western Tour," vol. ii. p. 132. See also "Notes on the Roads, Camps,
and Mining Operations of the Romans in the Mendip Hills," by the Rev. Prebendary Scarth, in the
"Journal of the Archæological Society," June, 1878.
32
[BOOK I.
HISTORICAL SKETCH.
3 fathoms in height, in others so low that a man has much ado to pass in
creeping. The wideness of it for the most part is about 3 fathoms. The
cavern crosses many veins of ore in its running, and much ore has been thence
raised. About the middle of this cavern, on the east side, runs a narrow
passage into another cavern, which is between 40 and 50 fathoms in
length. At the end of the first cavern a vast cavern opens itself. I fastened
a cord about me and ordered the miners to let me down, and upon a descent
of 12 or 14 fathoms I came to the bottom. This cavern is about 60 fathoms
in circumference, about 20 fathoms in height, and about 15 in length: it runs
along after the raikes, and not crossing them, as the leading vault does. I
afterwards caused miners to drive forward in the breast of this cavern, which
terminates it to the west, and after they had driven about 10 fathoms they
happened into another cavern, whose roof is about 8 fathoms, and in some
parts about 12 in height, and runs in length about 100 fathoms."
Mr. McMurtrie, of Radstock, in the "Proceedings of the Somersetshire
Archæological Society, 1880," gives the following graphic description of
these caverns, as examined by him recently: "The approach to them is by
means of a perpendicular shaft, about 2 feet square and 55 feet in depth,
which the explorer requires to descend by a series of ladders fastened to the
shaft-side, or by bucket and windlass, as may be preferred. On reaching
the bottom a narrow passage leads away through the 'old men's workings,'
sloping gently at first, then more abruptly, the cheeks' of the vein
getting gradually closer together, until it is difficult to force a passage
through, and at a distance of 20 yards a short ladder leads into the first part
of the cave. Up to this point there can be no question that the path
traversed has been formed by the hand of man, but the explorer can have
equally little doubt, when he reaches the foot of the ladder, that he has
entered the domain of nature.
((
<
Proceeding onwards in a downward direction, we traverse a vaulted
passage, with a Gothic roof fretted with stalactite, the floor either being
covered with stalagmites or soft brown mud. Near this point two other
lodes have evidently crossed the cave, and a portion of the débris from them
lies piled upon the floor; but the old miners must have had a kindly regard
for these caves, which we in our generation do not always possess, for it is
surprising how little injury has been done in the course of mineral workings,
which seem to have intersected them at numerous points. Before going far
we turn sharply round to the right, and should notice the smoothness with
which the walls of the cave have been rounded off, as if by the action of
water, although other agencies may also have been at work.
A good
opportunity is here afforded of examining the roof, in which I was curious to
ascertain whether any crevice or slip existed which might throw light on
the original formation of the caves, but for the most part I saw no trace
of these.
"The cave now gradually widens out and increases in height as we
approach the point A on the diagram, where we find ourselves in what is
certainly the most beautiful, although not the largest, of the series of caverns
I am endeavouring to describe. It is tortuous and irregular in shape, so
that it is not all visible from any one standpoint; but from where it widens
CHAP. II.]
THE CAVERN AT HARPTREE.
33
out as we approach, to where it again diminishes into a narrow passage, it
measures about 100 feet in length, and in the centre it attains a height of
over 30 feet. While the principal chamber here curves gently round to the
left, another branch of the cave strikes off to the right, so that this forms a
centre from which three passages radiate, and exactly at the point of junction
the floor is completely blocked by a stalagmite of gigantic dimensions-so
exactly resembling a bee-hive that it has given that name to the chamber in
which it occurs.
Turning to the right out of the bee-hive cavern at A, we now enter
a different branch of the cave, which is for the most part more narrow
and tortuous than that we have hitherto traversed. The inclination is
still inwards, and at first the passage is fairly lofty, but we soon come to a con-
tracted part, through which it is scarcely possible to crawl. Once through this,
the passage becomes larger again, and in proceeding inwards the floor is
found to be covered with a layer of soft red earth or clay, which points to a
considerable flow of water through this channel at some former time. The
deposit is deepest in the middle, being rounded in the centre like a well-
formed road. At a distance of 60 yards from the bee-hive cavern this
passage terminates in a small cross chamber of some little height, the
floor of which is five or six feet deeper than the passage by which it is
approached.
“In one corner of the chamber there is a vein of ore which has formerly
been worked. The cavern soon diminishes to a mere passage, and at one
point becomes so contracted as only to leave room to crawl, but it enlarges
again, and becomes very steep as it enters the great cave B. This
cavern is rudely circular in form, and is probably the largest in England:
its greatest diameter is 100 feet. It is dome-like in shape, and its total
height is 110 feet. In one corner of this cave there is a considerable depth
of débris, which has apparently come from the entrance to another cave, for
on clambering over this débris and mounting a ladder, the passage to
another large cavern is discovered, evidently the one referred to by Beau-
mont. Part of this passage bears evidence of being shaped by human
agency, and is doubtless the driving done by Beaumont. This third cavern
is 65 feet in length, 10 in width, and of considerable height. In this
instance there is every appearance that the cave has been formed in the
line of a chasm in the rock, resembling a mineral lode; but its smooth
unchiselled sides and stalactite roof prove it to be purely natural. Separated
from it by a contracted neck at the inner end is an extension of the same
cave, which the explorer must approach with caution, for he suddenly finds
himself on the edge of a chasm, which, from the sound of stones thrown
down, is probably 30 or 40 feet in depth, with a similar height over head,
and 20 feet in width; but this has not yet been fully explored, and no
further openings have been found in that direction."*
The author of this description next considers the probable origin of
these caverns. Referring to Sir Charles Lyell's description of caverns
in the Mountain Limestone, he supposes that waters charged with carbonic
*Mr. McMurtrie expresses his belief that most of the workings on the Mendips are not older than
the fifteenth century.
D
34
[BOOK I.
HISTORICAL SKETCH.
acid passing through the natural fissures dissolved out the lime, and left
the passages and caves to be eventually filled in by a secondary action with
stalactites and stalagmites. All the conditions described by Mr. Beau-
mont, and those also by Mr. McMurtrie himself, appear to indicate the
work of the ancient miners, whose waste-heaps abound on the surface. It
is evident that the shaft was sunk upon a lode, and at the bottom of
the shaft, and along the gallery, and in some fissure at right angles to it,
lead ore has been found. Lead ore was also found in the passage beyond
the great cavern B.
"Barrows are to be found scattered all over the tableland, and in one of
its highest parts the slope is crowned by a group of nine, visible at great
distances, and standing out against the sky like giant anthills.
3
They have
yielded at various times the usual quota of bones, pots, and weapons, but
whether they are British or Euskarian does not seem as yet decided. The
traces left by the Romans are, however, more fruitful and more interesting.
At what is now called Charterhouse Manor-no Roman name has survived
-the Romans worked for lead ore. At some distance from the modern
smelting-place there was a large camp, and, at the mine itself, a smaller for-
tified outpost. At present the mining is carried on by re-smelting the refuse
of the Roman workings. It is in digging up this débris that the relics of
the Romans have been brought to light. They are of the most varied kinds, and
from them may be read a curious history of the social life in this little hill
station. The mining instruments are very numerous, fragments of spades
and other iron tools, scales and weights.* Two pigs of lead, not inferior
in neatness or purity to those produced at this day, have been found.
The pig preserved at the mine is 24 inches long on the top and 4 inches.
wide, and on the bottom 19 inches by 3 inch, and is inscribed at the
top, IMP. VESPASIANUS AUG., and on the side, BRIT. EX. ARG. VE.
The words stamped at the side evidently tell that the lead has been
smelted from a silver vein in Britain. It is curious to notice how well the
shape is adapted for carrying on the backs of mules, by which means the
lead was conveyed to the port under Bream Down.† A pair of dice, made
in rough lead, seem to point to the fact that the Roman miners had the
same gambling propensities as the modern Californians. ‡ Hundreds of
brooches, from the richly enamelled brooch of some prosperous overseer, to
the simple clasp, or safety pin, for that is the form of them all. All except
one have the pins broken off, thrown away no doubt as useless when that
was gone, as we throw away a button; but yet to a careful people they ought
to have seemed worthy of mending, for they are often solidly and finely
finished. Among many other things have been found spoons, lead and
ivory; a dinner-knife with a bone handle; several styli, with which the
mine accounts may have been kept; rough glass beads, perhaps the orna-
ments of some poor Keltic slave—if savages loved glass beads at that time.
But on the side of the hill above the mine is the most striking of all the
* Saturday Review, August 26th, 1882.
+ Bream Down is near Uphill, a mile or two below Weston-super-Mare. A Roman road has been
traced from Charterhouse to near Uphill, and one or two Roman pigs of lead were found on the line.
The writer here is in error. The cubes of lead found were really lead weights of four ounces, three
ounces, two ounces, and one ounce respectively, and were no doubt used for weighing the produce of the
assays of lead and silver.
CHAP. II.]
ROMAN PIGS OF LEAD.
35
remains, and the most characteristic-an amphitheatre, small, but regular
in shape, and still clearly traceable."
The Rev. Prebendary Scarth, in his paper on Dolebury Camp, on
Mendip, which was read before the Bath Natural History Society, December
7th, 1881, speaking of the camp near Burrington village, says: "It has more
the appearance of a Roman camp, and is much inferior in size to Dolebury;
Roman remains have been found in it, as well as in the caverns in the
Combe below, but still more ancient interments have been found in one of
the caverns near this spot. The hills around are scarred on all sides by
the ancient workings for lead."* To the south of these camps runs the Roman
road which traverses the Mendip Hills from Bream Down, an ancient port of
the Romans, on the Severn, where some earthworks exist, and Roman remains
have been found.† . Indeed, the earliest pigs of lead bearing the Roman
stamp have been found along the course of this road. The first in date bears
the stamp of Britannicus, carrying us back to the reign of the Emperor
Claudius. It was in his reign that this part of Britain was brought under
Roman rule; it therefore seems probable that lead was known to the ancient
Britons before the coming of the Romans, and worked by them. From
Claudius to the Antonines we have evidence of Roman workings, in the pigs
of lead bearing the imperial stamp, in the coins and seals,§ and abundance
of other evidences which have been discovered in the process of uncovering
the sward to obtain the refuse of the old mining operations.
•
Leland, in mentioning the discovery of rich mines of lead in the Mendips,
notes the finding of an inscribed mass of lead near Blagdon.
It was
discovered in ploughing near Wookey Hole, in the reign of Henry VIII.,
and has been considered as a trophy erected to commemorate a victory.
"But," says Mr. Scarth, "the recent discovery of thin pieces of lead at
Charterhouse, stamped with the imperial mark, only of later date, shows
that it was the custom to impress the imperial stamp upon masses of various
thickness and of different weights. I am strongly of opinion that the lead
was obtained from Wookey, and that the cavern there, which lately attracted
so much notice on account of the animal remains found in it, is an ancient
Roman mine. It needs no proof to show that the Romans did form vast
caverns, and penetrate into the heart of the hills in pursuit of minerals."||
Relative Weight of Pigs of Roman Lead found in Britain. Given by the Rev.
H. M. SCARTH, M.A., Preb. of Wells, in the "Journal of the British
Archæological Association," June, 1875.
BRITANNICUS, A.D. 44-48. Weight, 163 lbs.
CLAUDIUS, A.D. 49. No weight given.
""
A.D. 41-54. Length, 17 inches on inscribed side, 20 inches on the other. No
weight given.
No weight given.
*Phelps's "Somerset," vol. i. p. 26.
+ Hoare's "Ancient Wilts," vol. ii. p. 42.
Journal of Archaeological Association," vol. for 1875.
Reports of Cambridge Antiquarian Society, vols. 1878 and 1880.
The Rev. H. M. Scarth's "Notes on the Roads, Camps, and Mining Operations in the Mendip
Hills," in the "Journal of the British Archæological Association.'
D 2
36
[BOOK I.
HISTORICAL SKETCH.
Nero, a.d. 60–68. 156 lbs. nearly.
VESPASIAN III., Consul A.D. 74. 179 lbs.
""
ས”
""
A.D. 76. 150 lbs.
" (Camden
Twenty pigs found. "Massas plumbeas forma oblongiore sed quadrata ”
Brit. edit. 1607, p. 463). These seem to have been rather leaden bands or
thin pigs. No weight given.
DOMITIAN VII., Consulate, A.D. 81.
دو
""
Found at Chester.
""
156 lbs.
168 lbs.
Matlock. 127 lbs.
HADRIAN, A.D. 117-138. 193 lbs.
""
""
""
""
""
""
""
Snailbeach, Minsterley, Westbury. 190 lbs. 6 ozs.
Snailbeach. 193 lbs.
Snead. 190 lbs.
Bath. 195 lbs.
ANTONINUS AND VERUS, A.D. 163-169. Bruton, Somerset. 50 lbs.*
""
""
""
""
""
Inscribed IMP. DVOR. AVG. ANTONINI ET VERI ARMENIA CORVM.
Found on Matlock Moor, 1783. 83 lbs. Length, 20 inches;
width, 4 inches.
Hexgrove parish, Mansfield, Notts. 184 lbs.
On the north bank of the river Almond, at its junction with the
Tay. An oblong bar of lead, 73 lbs. weight. XJ ተ
ANTONINUS PIUS, A.D. 166. 79 lbs.
99
""
""
""
Wade Street, Bristol. 89 lbs.
Charterhouse-on-Mendip, 1873. 223 lbs.
II
XXXX
It is not possible to determine the quantity of lead which has been
obtained from the refuse left by the ancient miners either in Somersetshire or
in Derbyshire. It is certain that in both counties the slags and slimes of the
Romans, and possibly of more recent miners, have been treated by modern
smelters for a considerable time. The following table gives the quantities
of waste matter which has been treated, and, lead obtained, on the Mendips
during the ten years ending 1880-
: Tons.
Tons.
""
""
""
1871. Slags and Slimes, 1888. Lead obtained, 632
1872.
1873. "
1874.
1322.
752.
""
""
""
""
""
""
99
1875.
""
1479.
1546.
""
19
""
""
""
""
1876. Slags and Slimes, 578. Lead obtained, 301
604 1877.
464 1878.
404 | 1879.
454 1880.
Tons.
Tons.
452.
""
539.
""
""
""
310
318
274.
"" 301
472.
II2
Of late years the slimes have been cautiously washed, and, thus enriched,
sold to the smelters at Bristol, which will account for the reductions in the
quantity given as smelted. The point for our especial consideration is that in
ten years upwards of 9,000 tons of lead have been obtained from the wastes still
remaining on those hills, notwithstanding that they have in all probability
been worked for a considerable time previous to our modern operations.
Not only was the Mendips worked by the Romans, but Mr. Thomas
Windesor, in the twenty-sixth year of the reign of Queen Elizabeth, being
attainted of high treason, an inquisition was held at Shepton Mallet to ascer
tain what lead mines at Lambden, on Mendip, the said Thomas Windesor
claimed to have. The depositions then taken proved that Windesor held
shares in a number of "gruffs," or mines, in and around Lambden, and that
in particular he held three-sixteenth parts in the mine called the "Herod
Gruff," which shares were subsequently forfeited to the Crown. There-
fore, some of the waste-heaps in this district may not be older than the
sixteenth century. The Crown still holds possessions in this portion of the
Mendips.
*Stukeley's "Itin. Curiosum," p. 151.
+ Wilson's "Prehistoric Annals," p. 392.
CHAP. II.]
ROMAN COPPER MINES.
of
37
Mr. James Yates, in his paper "On the Mining Operations of the Romans
in Britain,"* states that: "On a review of the preceding account, it appears
that fifty-four pigs of Roman lead have been discovered in different parts of
England. . . . . The pigs are remarkably regular in form, though differing
considerably in size and weight. The letters upon them are well formed."
Mr. Yates then draws the attention of his readers to the use of lead for coffins
by the wealthier Romans. "In the Museum of the Yorkshire Philosophical
Society there are four leaden coffins, found in one of the burial-places of
Eburacum.† Mr. Bateman, of Youlgrave, in Derbyshire, has two-one found
at York, the other at Colchester. Similar discoveries have been made in
London, Kent, Wilts, and Gloucester, and some of these coffins are orna-
mented in a singular and rather elegant style with circles, escallop shells,
and leaded astragals." Mr. Octavius Morgan describes a Roman tomb
discovered at Caerwent, in Monmouthshire, situated beside the Via Julia,
which led from Bath to Caerwent. It consisted of an outer rectangular
chamber, constructed with large slabs of stone, and containing a ponderous
stone coffin. The space surrounding this coffin, and intervening between it
and the inner sides of the chamber, was filled with small coal unburnt, and
rammed down so as to be tight and hard. The inside of the stone coffin was
lined with lead, fitting closely all round, soldered at the corners, and covered
with a plain oblong sheet of lead. This is a remarkable example of the
use of sheet-lead, showing that not merely the mining for lead was exten-
sively practised, but that the metallurgy of it was considerably advanced,
soldering being at that time practised. It is no less curious to find that
unburnt coal was used as a protective agent.
COPPER.—Many implements found in the Roman mines were described
by Pennant, and he says "the miners often discover the marks of fire in
old mines." (It was the practice with ancient miners to produce a fierce
fire against the rocks which they desired to rend, and when the rock was
sufficiently heated, to project cold water upon it, by which means it was
split sufficiently to rend easily.)
In the workings at Llandudno and on the Great Ormes Head several
tools of stone, of horn, and of bronze have been found. Of the stone imple-
ments the Hon. W. Owen Stanley writes: "These primitive implements
are similar to the water-worn stones or boulders found on the sea-beach at
Penmaen-Mawr, from which, very probably, those most suitable for the
purpose might have been selected." Mr. Stanley more fully describes a stone
maul found at Parys mine, near Amlwch, in Anglesea: "It is of hard basalt,
about a foot long, and evidently chipped at the extremity in the operation of
breaking other stony or mineral substances." These examples were pre-
sented to the British Museum. Pennant describes an iron wedge, 5½ inches
long, found in working the deep fissures of the Talar-goch strata in the
parish of Dyserth, in Flintshire.
Mr. Thomas Wright states that the copper veins at Llanymynech, near
Oswestry, were worked by the Romans. Roman coins of Antoninus,
* Proceedings of the Somersetshire Archæological Society, 1858.
+ Wellbeloved's "Descriptive Account of Antiquities," p. 59.
C. Roach Smith, "Journal of Archaeological Association," ii. pp. 296–301; "Archæological
Journal," x. p. 255; xii. p. 383.

38
[BOOK I.
HISTORICAL SKETCH.
Faustina, and other consuls have been found in the recesses of the mine.
Mr. Thomas F. Evans, of Amlwch, has described some cakes of copper found
in Anglesea, which are of considerable interest. He says: "On the 22nd
June, 1871, a countryman came to my house and asked to see me. On being
told I was not at home, he left a small piece of copper, with a request that it
SECTION
Fig. 7.-Roman Copper Slab.
might be handed to me on my
return. . . . . He told me that he
had found three round cakes of the
metal; one he had smashed with
a pick, in order to see what it was
made of, and the two others he
produced in the state in which
they were found. I soon bargained
with him for the three, and in a
very short time was at home,
cleaning the whole ones and put-
ting together the pieces of the
broken one. After some time thus
spent, I found that one of the
whole ones and the broken one
bore, in characters of unmistakable
distinctness, the letters IVLS,
which had evidently been stamped
upon the metal, while it was soft
with heat, by means of a circular
die."
The upper impression is made
upon a hunch, which appears to have been flattened down upon the tops of
the L and S. Mr. W. O. Stanley states that each cake of copper weighed
29 lbs. 6 oz., and measured 12 inches in diameter, and was 2 inches in thick-
The lump Mr. Stanley conjectures to have been added to make up
a fixed weight, and he therefore infers these to have been tribute-cakes.
Mr. Evans states that there are ancient workings a few score yards south of
the spot where these cakes were found, close to the road leading from
Penygarnedd to Garneglefu.
In the old copper workings at Copper Hill, Cwm-ystwyth, a number of
hard ellipsoidal stones have been found, which have clearly at an early period
been used as mining tools. Most of them have been considerably worn at
one end, and some are marked by a rough groove round the middle, by
which they seem to have been fastened to a handle. There is little doubt
that they belong to a time when iron was quite or almost unknown.
"Arma antiqua manus, ungues dentesque fuerunt
Et lapides."-LUCRETIUS.
And when, as in the arrow-head described by Herodotus-
ἀντὶσιδήρου ἐπῆνλίθος.”
"Journal of Royal Archæological Institute of Great Britain and Ireland."
•
CHAP. II.]
ROMAN MINES AT ABERGELE.
39
Again, Professor W. W. Smyth remarks: "At many points of these mines
the attention of the antiquary might be arrested by the term 'Roman Level,'
applied to certain galleries of small dimensions, in which the rock has
evidently been hewn by tools-not blasted with gunpowder; but it is hardly
necessary to observe that the retailers of tradition who here ascribe to the
Romans, as do the eastern Irish to the Danes, all work of more than a few
generations in age, overlook the fact that it is little more than two centuries
since gunpowder was generally introduced in mining, and that all subter-
raneous operations, up to the period even of Sir Hugh Middleton's successful
adventures, were effected by means of the hammer and 'gad,' or miner's
wedge. At Cwm Symlog and Esgair-hir, two of the most noted mines of the
seventeenth century, some of the tools have been discovered, amid the
refuse left by 'the old men.
"At ABERGELE some Roman remains have been discovered. Here, as
others have observed, are some of the most perfect Roman mines in the
kingdom. The mountain is cut across by a supposed Roman fosse, called
Fos-y-Bleiddiaid, or the Wolves' Fosse, an example of what may have been
produced before the invention of gunpowder-although the chasm may have
been produced by a primeval earthquake. In driving a level, towards the
close of the last century, the miners discovered that the Romans had been
deep in the bowels of the earth. They had followed the vein where it was
large enough to admit a man, and where it opened into a large chamber
they had cleared it quite away. Some curious hammers and other tools
were found, almost decayed to dust, with the golden hilt of a Roman sword.
The level which drains those works partly supplies the town with water.
The mines at Cae'rgwaith, at the foot of the same hill, are comparatively
modern, and were, we believe, very productive, until the water became too
great for the means of drainage then applicable. A few years ago a con-
siderable sum was expended here upon machinery and buildings, but some-
how or other the works, with every prospect of success, were abandoned.
The 'bowels' of this great rock have been proved to form a vast magazine
of wealth. Some forty years ago lead was raised in solid masses of several
hundredweight each, out of a shaft about a furlong to the east of the last named
spot; but the speculators had not the means to compete with the constant
influx of water. The old mines of Tyddyn-Morgan, in the same hill, were
wonderfully productive a century back. It has been handed down to the
writer, amongst family traditions, that hatfuls of old guineas were then
sported about by managers on the monthly reckoning-days. These workings
are supposed to be exhausted. Still farther west are the old mines of
Cefnogo', so called from one of the largest caverns in Europe, which
has a sort of natural Gothic grand entrance from the north. Some thirty
or forty years back, a large sum was expended in driving a level under
this mountain, without meeting with anything worth the search and
outlay." +
"In these 'Records' it has been maintained that the Mathews's of
* "On the Mining District of Cardiganshire and Montgomeryshire." By W. W. Smyth, M.A.,
F.R.S. ("Memoirs of the Geological Survey," vol. ii. part ii.).
+ "Records of Denbigh and its Lordship." By John Williams.
40
[BOOK I.
HISTORICAL SKETCH.
Denbigh (said to be iron-workers) could have been no more than tenants at
Lleweny, and it has been suggested that, since some of them are described
as 'of the Forge,' they were the first to erect ironworks at Bodfary, as the
Mathews's of Llandaff were the patriarchal iron-masters of South Wales."*
Mr. Weston, of Machynlleth, writing September 25th, 1858, thus describes
the discovery of ancient workings
made by him: "The work which
I have been opening is a shaft cut
down through the solid rock, fol-
lowing two lodes of copper, which
must have been productive, or so
great a work would not have been
prosecuted with such inadequate
means as they appear to have had.
It was full of water, and unknown
as a mine till I commenced my
work in May last. We have driven
T
Fig. 8.-Roman Pick.
a level into it within 8 feet of the
bottom, drawing off all but the mud.
The old shaft is about 50 feet deep,
and in a few days we shall clear the
mud and know all. An iron pick,
Fig. 8, was discovered, and we
have also found a fish spear, of the
same iron and manufacture, and
apparently coeval. In driving the
level we got on the course of the
lode, and have taken out some
tons of peculiarly rich ore. In the shaft is an immense lode, 10 feet wide,
with ore on the two walls; but these strings of ore rapidly widened in
going down, and I think form two lodes of ore, probably coming together
again in the deep with additional richness, as one dips straight and the
other underlies to it. This work is only half a mile from the town, and,
singular to say, it was commenced on the pinnacle of a high mound or
round hill, when a level of a few yards might have gone into the lode
nearly at the depth they attained by a work which must have taken them a
century, being down through solid hard rock.
"I do not think there is anything known in these parts as to the origin of
the mining operations in this district, though there are many works now in
progress which are supposed to be of Roman origin. We find at the bottom
of our work much burnt wood, and it is evident they had recourse to fire as
an agent, whether to soften the rock, or to heat it for the purpose of throwing
water on it to crack it, or for any other purpose, I am not skilled to say; but
that fire was used is certain. These old works are called here Ogo. This is
Ogo Wyddyn, Wyddyn being a name that was powerful in ancient times.
It is asserted that the Roman soldiers of slave degree were employed in these
"The Medieval History of Denbighshire." By John Williams (Glanmor). Wrexham: George
Bayley Hope & Co. 1860.
CHAP. II.]
ANCIENT METALLURGY OF COPPER.
4I
mines as a punishment, as also to enrich their commanders, but these are
sayings upon no reliable authority.”
The late Mr. J. Yates, in his Memoir "On the Mining Operations of
the Romans in Britain," writes: "I am indebted to Mr. Thomas Wright
for the information that the copper veins at Llanymynech, near Oswestry,
were worked by the Romans. Roman coins of Antoninus, Faustina, and
others have been found in the recesses of the mine. But further north the
evidences are much more ample and distinct."
Mr. Pennant describes a mass of copper, weighing 42 lbs. It is in the
shape of a cake of bees-wax, the diameter of the upper part being 11 inches,
and its thickness in the middle 2 inches. On the upper surface is a deep
impression, with the words SOCIO ROMÆ. It is conjectured that the
merchant or owner of the cake intended this inscription to signify that he
consigned it to his partner at Rome. Across this inscription is impressed
obliquely, NAT. SOL., meaning, perhaps, Natale Solum, and intended to show
that the Roman adventurer still remembered his native country. It was
found at Caer Hen, the ancient Conovium, four miles above Conway, and, as
Pennant observes, "was probably smelted from the ore of the Snowdon
Hills, where of late years some has been raised." This cake is still preserved
at Mostyn Hall, Flintshire, being in the possession of the Right Hon. Lord
Mostyn. An engraving of it may be seen in Gough's edition of Camden,
vol. iii. p. 190, pt. ix. fig. 13.
Professor John Phillips, in his "Thoughts on the Ancient Metallurgy and
Mining in Brigantia and other parts of Britain, suggested by a page of
Pliny's Natural History," asks: "Did the Cornish or Gallician miners make
bronze? For this is generally the compound indicated by the Roman æris
metalla, though it is undoubted that they also knew of and distinguished
zinc brass. There is, I believe, no instance of a single bit of pure tin or pure
copper being found with the numerous celts' which occur in so many parts
of England, nor is any other proof given that the direct union of tin and
copper was effected by the natives of Britain. Copper is so abundant in
Cornwall that it might tempt to the other hypothesis, but this copper is a
sulphuret: it is found united with sulphuret of iron in deep veins and in a
matrix of quartz, and these are things which render the production of pure
copper one of the most refined operations in smelting. Cæsar tells us
that the brass used by the natives of Britain was imported. Probably Cyprus
-colonised by the Phoenicians, to which old authors refer as the original
source of brass-with its ancient copper mine (Tamassus), which has
given its name to the metal, might be one of the points from which
bronze radiated over the Grecian, Roman, and barbarian world. It was
from Cinyras, the King of Cyprus, that Agamemnon received his splendid
breastplate, with twenty plates of tin, and its liberal additions of turquoise,
lazulite, or rather malachite, obtained, perhaps, from the soil of the island."*
"The works of 'Hoaioros, the Crawshay of antiquity, appear to have fixed
on Lemnos as the site of a foundry, on account of some volcanic appearances
there, but the tradition shows at least that the various operations of refined
metallurgy were not strangers to the islands of the Mediterranean; and the
* Plin. xxxiii.
42
[BOOK I.
HISTORICAL SKETCH.
uniformity of design and composition in the ancient celts, chisels, paɣeλλ¤,
and instruments of war, implies a common, and that not a barbarous,
origin. The perfection and variety and great proportions of the brass work
executed in the Grecian states and colonies may also be regarded as
indicating the local seat of the early as well as the later art of working in
brass."
Beckmann,* in his essay on tin and tinning, remarks "that most of the
Roman vessels were made of copper, and that these people were acquainted
with the art of tinning and silvering them, but that tinned vessels have never
been found, and silvered ones very rarely. (This will be accounted for by the
rapid oxidation of the tin pellicle and its removal.) Hence so many things
appear to have been made of what is called bronze, which is less liable to
acquire that dangerous rust or oxide known under the name of verdigris,
than pure copper. This bronze is sometimes given out as Corinthian and
sometimes Syracusan brass, as the golden-coloured coins of the first size were
considered to be Corinthian brass also."
Sufficient has been said to show that the Romans used copper extensively,
and the evidence appears clear that the Romans mined for and smelted
copper ore in Britain.
It appears almost impossible to determine with accuracy when copper
wa's first worked in Cornwall. Bronze vessels, weapons, and tools have been
found in Cornwall, but there is no evidence existing to show that either
bronze or brass were manufactured in that county. Notwithstanding, the
fact exists that copper, tin, and zinc are found abundantly in the mineral
veins which traverse the Cornish rocks. These three metals are those which
form the alloys respectively of bronze and of brass. Yet it is strange that,
with all the attention which has been given to the early history of tin mining,
there are to be found only a few very brief and unsatisfactory statements
relating to the discovery and use of copper.
Two causes probably may have led to this. In the mineral veins it is
usual to find tin near the surface, whereas the copper only begins to make
its appearance at some considerable depth below, requiring deeper mining
than the appliances of those early days would admit of. Tin not unfrequently
appears again in the lode after the copper ore has been worked through.
The oxide of tin (black tin) is very easily smelted, whereas copper cannot
be obtained in a pure state from the ore without a considerable knowledge of
metallurgy. In conclusion, it should be noted that Carew, in his "Survey of
Cornwall," affords an additional proof of the use of bronze celts in the ancient
mines of that county. "There are taken up in such works certain little tools'
heads of brass, which some term thunder axes, but they make small show of
any profitable use." Those bronze chisels were possibly used by the Romans
in cutting adits into mines. All those subterraneous works said to be
Roman are distinguished by being chiselled.
GOLD.-There is every reason for believing that gold was eagerly sought
for by the Roman invaders, and that the reports of its existence lured their
armies to Britain. Pliny the elder states that gold (auraris metallis) was
* "A History of Inventions, Discoveries, and Origins." By John Beckmann. Translated from the
German by William Johnston. Fourth edition. 1846.
CHAP. II.]
GOLD AND IRON MINES.
43
found in the stream-works (elutia), the stream of water washing out (eluente)
black pebbles, a little varied with white, and of the same weight as the gold.
The eager search, from the earliest times, for the precious metal in the "tin
streams" of Cornwall, exhausted them of the gold they once contained, in
the same way as we find them now nearly exhausted for tin itself.
•
The existence of gold in the rocks of Caermarthenshire and of North
Wales is proved, and their discovery by the Romans is rendered more
than probable. Professor W. W. Smyth* has well described the gold mine
of Gogofau. "The ancient gold mine of Gogofau, near Llan-Pumpsant, in
Caermarthenshire, was probably worked by the Romans, who appear to have
had a station in the vicinity. The majority of the workings, extending to a
considerable depth for some acres over the side of the hill, are open to the
day, or worked, as usual in the early days of mining, like a quarry.
Here and there a sort of cave has been opened upon some quartz veins, and
in some cases has been pushed on as a gallery, of the dimensions of the
larger levels of the present day, viz. 6 to 7 feet high and 5 or 6 feet wide. . ...
If we examine Pliny for the state of knowledge on this subject among the
Romans, we find that gold was obtained by three processes: first, washing
the sands of certain rivers; secondly, following the lode by shafts and levels
(puteis et cuniculis), whilst the earth is supported where necessary by props
or pillars of wood; thirdly, by excavating hollows of larger magnitude,
supported for a time by arches of rock, which are afterwards gradually
removed, to allow the whole superincumbent mass to break in. The ore is
broken, washed, burnt, ground to powder, and pounded in pestles."
IRON ORE.-It is necessary that it should be distinctly understood that
this volume will not embrace the consideration of the production of iron ore
from the coal measures, which is especially treated of by Mr. Richard
Meade.t The Romans worked their mines with considerable skill, and
they probably used the same means for ventilating their iron mines and
their collieries as were used in the days of Agricola, and they must have
had some appliances for raising the water out of the mines, either by pumps
or buckets. Pliny, in his account of well-sinking, says "that, besides the
principal shaft, it was the practice to sink vent-holes on each side of the
well, both right and left, in order to receive and carry off the noxious
exhalations. Independently of these evils, the air becomes heavier, from the
greater depth merely of the excavation, an inconvenience which is remedied
by keeping up a continual circulation with ventilators of linen cloth."
"In Strabo's days," says Mr. Pennant, "iron was in great plenty, as he
mentions it among articles of exportation." He describes an iron tong,
which, he says, "exactly resembles the instrument placed in the hands
of Vulcan in ancient works of art." He also mentions some remains dis-
covered. "Immense beds of iron cinders are to this day found in the Forest
of Dean, the reliques of the Romans; others in Monmouthshire. An iron
"On the Gogofau Mine," in "Memoirs of the Geological Survey
of Great Britain," p. 481; see also Murchison's "Silurian System," and "Archæological Journal,"
vii. 173.
* W. W. Smyth, M.A., F.R.S.
The Coal and Iron Industries of the United Kingdom." By Richard Meade, Assistant Keeper
of Mining Records. Crosby Lockwood & Co. 1882.
‡ Georgii Agricolæ, "De re Metallica." Libra xii. Basileæ. MDLVI.
44
[BOOK I.
HISTORICAL SKETCH.
furnace was discovered near Miskin, the seat of William Basset, Esq.,
beneath which were found a coin of Antoninus Pius and a piece of earthen-
ware; and, finally, others in Yorkshire, also accompanied with coins, all
of which evince the frequency of iron foundries during the period of the
Roman reign in Britain. These cinders are not half exhausted of their
metal, for the Romans knew only the weak power of the foot-blast. They
are now worked over again, and yield a more kindly metal than what is
produced from the ore."
*
Ariconium, the modern Weston, in Herefordshire, near the Forest of
Dean, was the site of Roman ironworks. "At a place called Cinder Hill,"
observes Mr. T. Wright, "we have only to turn up the surface to
discover that it consists of an immense mass of scoriæ. It is evident that
the Roman town of Ariconium possessed extensive forges and smelting
furnaces, and that their cinders were thrown out on this side of the town
close to the walls." The Romans appear to have smelted iron ore in Sussex.'
We find that the Romans mined for iron, not only in Dean Forest and
on the Mendip Hills, but in Derbyshire, Yorkshire, and Cheshire. In
Durham, Northumberland, and Cumberland, the remains of rude furnaces.
have been found, overgrown by peat or buried beneath the accumulated soil.
The masses of iron slag that have been discovered in the neighbourhood of
Habitaucum and Lanchester are much heavier than those produced from
modern furnaces, the reduction of the ore not being then so perfect as
it is now. When the commons in the neighbourhood of Lanchester were
brought into cultivation, two large heaps of scoriæ had to be removed,
and near one of them a pair of iron tongs, very much like those blacksmiths
use now, was found buried.
Mr. Champernowne, of Dartington Hall, near Totnes, informs me that very
deep pits are to be seen at Tuckenhay, in the parish of Cornworthy, on the
southern side of a branch of the river Dart, which have at some remote date
been opened upon deposits of hæmatite. These workings are traditionally
referred to the Romans, and often to a "savage people" earlier than the
Romans. The iron ore on the Brendon Hills and on Exmoor is said to
have been discovered by the Romans. Some open workings on the latter
are commonly regarded as of Roman origin, a large and important vein
of spathose iron ore being known as the "Roman vein."
After the departure of the Romans from Britain we have for a long period
no light to guide us in our endeavour to trace the progress of mining.†
* Thomas Wright's "Wanderings of an Antiquary," p. 23. See also, "The Celt, the Roman, and
the Saxon"; "Contributions to Literature," by Mark Antony Lower, M.A.; Mantell's "Geology of
Sussex"; and "Mining Operations of the Romans," by Professor John Phillips, pp. 7, 31, 32.
†The Bishop of London, in his new edition of Camden, says it is supposed the Romans never were
in Cornwall. His words are these, speaking of Biscawoone: "If the Romans never passed the Tamar,
as indeed there are neither ways nor coins to prove that they did "-and quotes for it a marginal note,
"Comments upon the Monument of Julius Vitalis," by Dr. Musgrave (pp. 124-126). Tonkin, in his
notes on Carew's "Survey," says: "Whatever became of Roman ways in Cornwall, it is most certain that
great quantities of their coins, urns, &c., have been found from one end of the county to the other."-
Carew's Survey," p. 28. De Dunstanville's edition (1811).
CHAPTER III.
MINING TO THE EIGHTEENTH CENTURY.
TIN.—The Saxons, under Athelstane, invaded and gained possession of
Cornwall about 947; but although many Saxon chiefs appear to have
settled in the county, there is no evidence of their having in any way aided
mining. There is no mention in "Domesday Book" of mines. The only
actual evidence connecting the Saxon with mining appears in the "Journal of
the Royal Institution of Cornwall," No. VIII. 1867. There we find an account
of the discovery, in 1774, in a stream-work at Trewhiddle, near St. Austell,
of a considerable quantity of Saxon coins, inscribed with dates from 757 to
901. Sir Edward Smirke finds in the "Acta Sanctorum" a story relating to
John of Alexandria, who died A.D. 620, which relates to Cornish tin. This
story bears on the miraculous interposition of an angel, to protect a ship
bearing tin from Cornwall to Alexandria, and on the magical transmutation
of the tin into silver on the voyage. This superstitious tale shows us that in
the sixth and seventh centuries the Alexandrians knew that tin was derived
from Britain, that the priests of the Church of Alexandria possessed
trading vessels, and that these ships brought tin to them through the Straits
of Gibraltar.
Through the Middle Ages the European nations must have drawn their
supplies of tin from this country. It is evident that there was an eager
search for tin on the continent of Europe, as it is recorded that that metal
was found in Bohemia in the thirteenth century, and subsequently in Saxony.
Beckmann* thinks that the account given by Hagee, that the Bohemian
mines were known so early as the year 798, is entirely void of foundation.
Pryce, in his "Mineralogia," says: "A tinner in the time of Richard, King
of the Romans, upon some disgust at home, went over to Saxony and taught
the natives to seek for tin."
A considerable demand for tin must have sprung up when bells
were first introduced in churches in the sixth and seventh centuries.
It is stated, indeed, that a bell was cast in the fifth century, when Paul,
Bishop of Nola, in Campania, introduced a bell into his own church.
Hence the name campana, a bell. A century later bells were commonly
used in France, and also in the churches of Britain. All the old bells were
alloys, in varying proportions, of tin and copper. Sometimes they contain
a little zinc, and occasionally silver is found in them, and there has always
been an idea that silver improved the tone. Mr. Hawkins states † that the
sale of tin was greatly increased by the demand produced by the use of
* Beckmann's "History of Inventions and Discoveries," vol. ii. p. 226. Translated from the German
by William Johnston.
† "Transactions of the Geological Society of Cornwall," vol. iii. pp. 122, 124.
46
[BOOK I.
HISTORICAL SKETCH.
bronze cannon in the fourteenth century. "Latten ware," or pewter-a mixture
of tin and lead in various proportions-came into use in the fifteenth century,
and the finer varieties, being capable of taking a high polish, were much
used at the great feasts of the nobles. Tin was at this time largely employed
in the East for covering copper vessels. The Romans, at a much earlier
period, appear to have been acquainted with the process of tinning. Syra-
cusan bronze and Corinthian brass-being liable to that dangerous rust, or
oxide, known as verdigris-were protected by being covered with tin, and
sometimes with silver. This art of plating was never lost, and in the twelfth
and thirteenth centuries considerable quantities of tin went by the way of
Gibraltar to Venice, Pisa, and to Constantinople.* The art of tinning iron
appears to have been invented either in Bohemia or Germany, and intro-
duced at a later period into England and France; it is evidently much more
modern than the tinning of copper. The first vessels made by the bottle-
makers were flasks of copper tinned, which in old times were used in war
and on journeys.†
Our readers cannot fail to be interested in the speculation of Beckmann,
which we here quote. It shows the amount of learning which has been.
expended on this curious subject.
In the beginning of the thirteenth century, Venice, Pisa, and Genoa were
the most important of the commercial states of Europe. Venice, according
*"A History of Inventions and Discoveries and Origins." By John Beckmann. Translated from
the German by William Johnston.
+ Ibid. vol. ii. p. 226.
:
“Bedil (2), according to the most probable derivation, means the separated. It may therefore,
consistent with etymology, be what Pliny calls stannum, not tin, but lead from which the silver has not
been sufficiently separated. The passage in Isaiah, chap. i. ver. 25, appears to afford a confirmation,
because the word there is put in the plural, equivalent to scoria, as something separated by fusion.
"Others derive bedil from the meaning of the Arabic word tin, badal, that is, substitutum, succeda-
neum. In this case, indeed, it might mean tin, which may be readily confounded with silver.
"The questions why bedil has been translated tin, and how old this explanation may be, are answered
by another. Is KaσoiTEρoç tin? If this be admitted, the explanation is as old as the Greek version of the
Seventy Interpreters, who in most passages, Ezekiel, chap. xxii. vv. 18 and 20, and chap. xxvii. ver. 12,
express it by the word kaoσirepos. In the last-mentioned passage tin and iron have exchanged places.
The Targumists also call it tin; and some, with the Samaritan translation, use the Greek word, but
corrupted into kasteron, kastira. It is also the usual Jewish explanation that bedil means tin, as oferet
does lead.
"In the oldest passage, however, where bedil occurs, that is, in Numbers, chap. xxxi. ver. 22, the
Seventy translate it by póλißoç, lead, and the Vulgate by plumbum; and, vice versa, the Seventy for
oferet put kaσoirepos, and the Vulgate stannum. This, as the oldest explanation which the Latin trans-
lator found already in the Septuagint, is particularly worthy of notice. According to it, one might take
, pólißos, stannum, for the stannum of Pliny, lead with silver. The gradation of the metals still
remains; the kaoσirepog of the Seventy may be tin, or real lead. It may have denoted tin and lead
together, and perhaps the Seventy placed here rasoirɛoos, in order that they might have one metal more
for the Hebrew oferet. But from this explanation it would follow that Moses was not acquainted with tin.
"The East has still another name for lead and tin, TN, anac, which occurs only in Amos, chap. vii.
vv. 7 and 8, but is abundant in the Syriac, Chaldaic, and Armenian, and comprehends plumbum, nigrum,
and candidum.
"In the Persian, tin is named kalai, resâs, arziz, which are all of Arabic, or, like kalai, of Turkish
extraction. None of these have any affinity to kaoσireρos or bedil.
ισ
"As tin is brought from India, it occurred to me whether the oldest name, like tombak, might not be
Malayan. But in the Malayan tima is the name for tin and lead. ('Relandi Dissertat. Miscell.,' iii.
p. 65.) It would, indeed, be in vain to look for Asiatic etymologies in regard to kaooirepos, since,
according to the express assertion of Herodotus, the Greeks did not procure tin from Asia, but from the
Cassiterides Islands. The name may be Phoenician, and though Bochart has not ventured to give any
etymology of it, one, in case of necessity, might have been found equally probable as that which he has
given of Britannia. But it appears to me more probable that the word is of Celtic extraction, because
similar names are found in Britain, such as Cassi, an old British family; Cassivelaunus, a British leader
opposed to Cæsar; Cassibelanus, in all probability the same name in the time of Claudius. Cassi-ter,
with the Greek termination og, seems to be a Celtic compound, the meaning of which might, perhaps, be
found in Pelletier, Bullet," &c.-Beckmann's "History of Inventions," p. 209. Bohn's edition (1846).
CHAP. III.]
BRONZE AND "LATTEN" WARE.
47
to Mr. W. C. Borlase, received the tin from Cornwall by the way of Bruges,
in Flanders, while Pisa and Genoa carried on
and Genoa carried on a direct traffic in their
own vessels.*
Mr. Hawkins, in the "Transactions of the Geological Society of Corn-
wall," gives an interesting record of the commercial industry of Florence,
borrowed from a manuscript entitled "La Pratica della Mercatura," com-
posed by Francisco Balducci Pegolotti between the years 1332 and 1345, and
printed in 1766 from the original manuscript in the Riccardian Library.†
Balducci states that "the tin is imported from Cornwall, in England, in large
slabs, of a long square form, each slab weighing about one cantaro and a
third, Barbaresque weight of Majorca, where, and at Venice, they make
bundles of tin rods, bound together with rods of the same metal; each bundle
made up at Majorca weighing about one cantaro and a quarter, Barbaresque
weight of Majorca. The loss in smelting down the slabs and in casting the
rods at Majorca was from 1 to 2 per cent., and the expense of making the
rods was one soldo of the small Majolichin money per cantaro; and because
every one of the rods which was made at Venice had on it the stamp of
St. Mark, those of Venice fetched a better price in the Levant, by 2 to 3 per
cent., 'than those of Majorca or Provence, though they were both equally
good."
Mr. Hawkins quotes also the works of Marinus Sanntus to prove that
much Cornish tin went to the Levant, and was passed on thence to India.
Looking, however, at the fact that tin was obtained from the islands of the
Indian Archipelago, this appears somewhat problematical. Mr. Hawkins
quotes from another portion of Balducci's work a curious statement, as it
respects the prices of tin at this time. The worth of 1,000 lbs. of tin in Corn-
wall was then 10 marks sterling, the value of the mark being equal to
4 florins.
A convention between the Papal See and England in 1337 fixed
"that a pound of gold, being coined into 90 florins, was equal to 62
soldi of 12 denarii, so that the relative value of gold and silver was as
I to 12."
:
Balducci informs us that the cantaro of tin weighed 140 lbs. of Pisa, or
145 lbs. of Genoa, and the cwt. of tin of 112 lbs. in London was equivalent to
120 lbs. or 122 lbs. at Bruges.
William the Conqueror granted the Earldom of Cornwall to his half-
brother, the Earl of Morton, in the twelfth century, and he held 248 manors
in the county, but we learn nothing of the value of any mineral possessions.
In 1140 the son of Earl Morton, William, forfeited his rights, and they
remained with the Crown until the illegitimate son of Henry I., Reginald de
Dunstanville, was made Earl of Cornwall by Stephen, about 1140. In 1175
the earldom reverted to the Crown, and Henry II. retained it in his posses-
sion. We learn nothing respecting mining in this period. Borlase‡ says
the produce of tin in Cornwall was very inconsiderable in the time of King
John, and the property in the mines precarious, the tin raised being engrossed
by the Jews. § The right of working the tin was wholly in the King, as Earl
* "Historical Sketch of the Tin Trade in Cornwall." By William Copeland Borlase.
+ "Transactions of the Geological Society of Cornwall," vol. iii. p. 129.
Borlase's "Natural History of Cornwall."
§ Ibid.
1
48
[BOOK I.
HISTORICAL SKETCH.
of Cornwall. The tin farm of Cornwall then only amounted to 100 marks
(£66 13s. 4d.) per annum, while the tin of Devon was farmed at the same
time for £10.
On the 29th October, of the third year of King John, 1201, a charter was
granted to the tinners of Cornwall and Devonshire. This is preserved in
the Record Office, and is given in facsimile by Sir Henry de la Beche in
his "Geological Reports of Cornwall and Devonshire." It commences:
"Johannes Dei gratia Rex Angliæ, &c. Sciatis nos concessisse quod
omnes stammatores nostri in Cornubia et Devonia sint liberi et quieti
de placitis nativorum, dum operantur ad commodum firmæ nostræ vel
commodum marcarum novi redditus nostri quia stammariæ sunt nostra,
dominica, &c.
"Testibus Willielmo Comite Sarresburiæ, Petro de Stokes, Warino filio
Geroldi. Data permanum S. Wellensis Archidiaconi apud Bonam Villam
super Tokam vicesimo nono die Octobris, anno regni nostri tertio."
It is rather the delusive echoes of a tradition than the clear voice of
history, which informs us that John inflicted on the Jews, inhabiting the two
western counties, acts of severe oppression. He made them advance money
to meet the expenses of his wars, and when they solicited repayment he
drove them from their homes, took their mines from them, and diverted
the power of the Stannaries to his own base ends. There exists a strange
tradition, that King John compelled the Jews working for tin upon Dart-
moor, to build Christian churches. All the churches on the Moor are of
a similar character, but their origin is uncertain.
The Stannary Court appears to have originated in the time of Athelstane
(950), after his conquest of the county of Cornwall and the Scilly Islands.
During the period when Richard, Earl of Cornwall and King of the Romans,
held possession of the county, the produce of the tin mines is said to have
been considerable, but we have no exact information.
In 1197 Hubert, Archbishop of Canterbury, who was left by Richard
Cœur de Lion to administer the affairs of the kingdom during his absence in
France, turned his attention to the tin mines of Cornwall. He sent into the
county one of his creatures, William de Wrotham, as Warden of the Stan-
naries. He imposed new taxes on the tinners, and raised considerable sums
of money for the exhausted Exchequer. Wrotham, however, at the same
time established useful laws and regulations.
It appears certain that the Jews held with remarkable courage and great
tenacity the tin mines of Cornwall until the time of Edward I. Treading in
the footsteps of his grandfather, that king without scruple robbed the Jews,
and when he could no longer drain any gold from their coffers, he published
a proclamation about 1201, banishing the Jews from the kingdom for ever.
The Jews had rendered themselves odious by their usury and extortion, and
the people were greatly pleased at this act of the King. The clergy especially
were so greatly delighted at the exile of these enemies of the Christian faith,
that they indemnified the King by granting him a tenth of their benefices.
In 1305 Edward I., on the 10th of April, in the thirty-third year of his reign,
granted a charter to the tinners of Cornwall and Devonshire. They had
previously formed one body, and it was their custom to meet every seventh or
CHAP. III.]
CHARTERS GRANTED TO THE TINNERS.
49
eighth year, to concert their common interests and regulate their proceedings,
on Hingston Hill, near Callington. They were now divided, and formed
distinct bodies. Five towns in Cornwall and three in Devonshire were
named, where the tin ore was taken for "Coinage." That is, the blocks of
metal were there stamped, and a portion from each was retained for
the King or his representatives. These were called coinage towns.
Each
tinner was now permitted to sell his own tin, unless the King insisted on
buying it.
The charter of John (A.D. 1201) was confirmed in the thirty-third year of
Edward I. (A.D. 1305),* and the tinners of Cornwall and Devon acted under
new and improved laws. These charters (pro Stannatoribus in comitatu
Cornubiæ) are preserved in the Rolls in the Record Office, and they are given,
in facsimile, in De la Beche's Report already quoted. The original of the
charter of Edward was kept in Luxullion Church, whence for greater security
it was removed to Lostwithiel during the civil wars, and was there destroyed
by the army of Essex in 1644.†
In the eleventh year of Edward III. (1337), we learn from a charter roll,
preserved in the Record Office, of "The grant to Edward, Duke of Cornwall
and Earl of Chester, the King's son, of the Sheriffalty, and divers castles,
manors, &c., in Cornwall and Devon, declaring his creation to the
Dukedom."
After reciting that, with the unanimous assent and advice of our
present Parliament, &c. &c., we have "given to our said son the name
and honour of Duke of Cornwall, and have created him Duke of Corn-
wall, and have girt him with a sword," &c. &c.,; the castles, manors, &c.,
granted by the charter, are then enumerated, and it proceeds :-
"Also our Stannary in the same county of Cornwall, together with the
coinage of the same Stannary, and with all the issues and profits thereof
arising. And also the explees, profits, and perquisites of the Stannary and
mine courts in the same county, except only one thousand marks, which we
have granted, for us and our heirs, to our beloved and faithful William de
Montacute, Earl of Salisbury, to be received by him and the heirs male of
his body lawfully begotten, from the issues and profits of the coinage afore-
said, under a certain form in our other charter, to the same Duke thereof,
made more fully declared, &c. &c. &c. Given by our hand, at Westminster,
the eighteenth day of March, 1337. By the King himself and the whole
Council in full Parliament.”
After the exile of the Jews, the mines were for a long period neglected.
Probably this people had taken the tin streams and shallow mines into
their own charge, and when they were driven from them, there were but few
men left capable of working them. The tin deposits in Cornwall were at
* Edward I.—for the advancement of the Stannaries of Cornwall-frees the Tinners from all pleas of
the Natives touching the Court, and from answering before any justices, &c., concerning the Stannaries,
save only the Keeper of the Stannaries. Indemnifies them from Tolls. Gives them leave to dig Tin and
Turf anywhere in the said County; and to turn Water-courses for their works at pleasure.
Edward III.—Indenture, dated 11th July, Anno 32, grants unto John Ballanter and Walter Bol-
bolter all his Mines of Gold, Silver, and Copper, in the County of Devon, for two years, with libertie to dig
and search (except in Gardens yielding 20 marks the first year, and the fifth part the second year), and all
other persons are excluded from digging there.-Sir John Pettus, "Fodina Regales."
† According to a MS. of the time of Elizabeth, entitled "The Bailiff of Blackmore."
E
50
[BOOK I.
HISTORICAL SKETCH.
this time entirely in the hands of the King, and for the purpose of increasing
his own revenues, he granted many privileges to the new adventurers, as
Tinners. In 1240 Cornwall is said to have supplied all Europe with tin.
Carew, in his "Survey of Cornwall," writing from information obtained
from "Master William Carnsew," who had seen John's charter, says: "After
this it happened that certain gentlemen, being lords of seven tithings in
Blackmore, whose grounds were best stored with this mineral (tin), grew
desirous to renew this benefit; and so upon suit made to Edmund, Earl of
Cornwall, sonne to Richard, King of the Romans, they obtained from him a
charter with sundrie privileges, amongst which it was granted them to keepe
a court, and hold plea of all actions (life, lymme, and land excepted), in con-
sideration whereof the sayd lords accorded to pay the earle a halfpenny for
every pound of tynne which should be wrought, and that for better answer-
ing this tax, the said tynne should bee brought to certayne places purposely
appointed, and there prized, coyned, and kept, until the earle's dues were
satisfied. Again, the lords of these tithings were there allotted unto them
the tole-tynne within those tithings, which their successors do yet enjoy.
This charter was to be kept in one of the church steeples within those
tithings-and the seale had a pickaxe and shovele in saultier graven
thereon."
Wrotham, in his capacity of Warden of the Stannaries, established new
laws, which secured much freedom to the tinners. He, however, made
certain regulations which were mainly to enforce the King's right, and to
increase the toll on tin. The liberties which John's charter ensured to the
tinners were, that "they should be quit of all pleas of serfdom," because
"the Stannaries are our royal demesne." The tinners were, "without
hindrance from any man, at all time to freely dig tin, and turves to melt it,
anywhere in the moors and in the fees of bishops, abbots, and earls, and should
buy wood for the melting, and divert watercourses for their works, as by
ancient custom they had been used to do." Again: "They should not be
compelled to leave work at the summons of any man but that of the chief
warden or his bailiff."
It is evident that, at the time of Wrotham, the Jews still held possession
of many of the mines in Cornwall. He continually speaks of "Christian
nor Jew." In the names of the jurors contained in his regulations we find
several Hebrew names. Professor Max Müller, in his "Chips from a German
Workshop," informs us that in the third year of King John (1201), Simon
de Dena, Dendone son of Samuel, and Roger Rabi affixed their names to
Wrotham's document. Even after their banishment some Jews appear to
have lingered behind. Roger le Jeu is named in the reign of Edward II.,
and Abraham the tinner, who employed three hundred men in the stream-
works of Brodhok. In olden time the tinners of Cornwall and Devon held
a meeting on Hingston Hill, near Callington, every seventh or eighth year,
to arrange their common interests; but after the Regulations of the Warden
Wrotham, Cornwall was separated from Devonshire. Five coinage towns-
or places where the tin was carried to be tried (coined) and marked—a piece
of tin being chipped off each slab as a royalty to the King or to the Duke
of Cornwall-were fixed on for Cornwall and three for Devonshire. These
CHAP. JII.]
THE STANNARY PARLIAMENT.
51
were Lostwithiel, Bodmynyan, Liskiriet, Treueru, and Helston for Cornwall;
and Tavystock, Asperton, and Chaggeford for Devonshire. The prisons of
the Stannaries were fixed at Lostwithiel and Lydeford. According to Carew,
these courts were not over remarkable for fair verdicts. The justice of
Lydford is celebrated in a rude verse:-
Who has not heard of Lydford Law,
Where in the morn they hang or draw,
And sit in judgment after,
The regulation of the Stannaries Court will not form the subject of
consideration in this volume. The examination of the laws relating to mines
and minerals would occupy much more space than can be afforded to this
subject.
Pursuing our historical sketch, Edward II., about 1327, granted the Stan-
naries to his favourite, Gaveston, and in the tenth year of his reign (1336) he
made over the coinage of tin to Stephen of Abyngdon, his butler, and John
Pecoke, his valet. At this time the tinners in Cornwall numbered only
500, whereas but a few years previously they numbered 3,000. In 1337 a
grant of the Stannaries was made to Edward the Black Prince, and we
are told the coinage in that year amounted to 4,000 marks. In the following
year the King, in the most capricious manner, seized all the tin produced,
and for a considerable time tin-mining was at a very low ebb. It was not
until 1376 that any measure of redress was sought for. In that year the
tinners obtained the sanction of Parliament to the rules and regulations
of the charter of Edward I. In the reign of Henry VII. (1489) the charters
were declared void, but after several years of severe struggle the forfeiture
was rescinded, and a free pardon granted to the miners.
In 1376 the tinners were able to obtain protection by Act of Parliament,
but until the reign of Henry VII., when the Wars of the Roses were
brought to an end, and England became more settled, the mines were almost
entirely neglected.
Henry VIII. did but little to promote the mining industries of England.
In 1509 Parliament passed an Act which decreed "that no person shall buy
tin or any wares made of tin out of the realm." This appears to have
resulted from the discovery of tin in Bohemia in 1240, and the subsequent
discovery of tin mines at Altenburg, in Saxony, in 1458.
(C
The Stannary parliament being allowed to frame their own laws, these
laws continued active through the reigns of Henry VIII. and Edward VI.
At Crockern-Tor, on Dartmoor, several parliaments were held, ninety-six
"jurates" being appointed, twenty-four from each coinage town in Devon-
Chaggeford, Aysberton, Plymton, and Tavistocke." At these, and at other
parliaments held at Lostwithiel and other Cornish courts, the weights and
measures to be used were fixed, and numerous regulations as to the coinage
of the tin were decided on. By these parliaments the tinners were allowed
the right of free search on any man's ground for tin. This was carried to
such an extent that no property was safe. Not only did the miners dig over the
waste lands, but they entered upon cultivated grounds, they put down their
pits in ornamental parks and in gardens. Eventually this evil was to a great
extent removed by the introduction of a system of “Bounding."
Bounding." This was
E 2
52
[BOOK I.
HISTORICAL SKETCH.
ruled by the following custom: The tinner who desired to make a search
must apply to the owner of the soil, and proceed with him to the spot he
wished to work. There and then he should take him "by the arme and
declare to him with a lowde voyce, that he may hear him-the cause of his
pitch, and the day when he pitched the same tyn worke." A turf was cut at
each corner of the ground selected, and regularly renewed by a person called
a "Toller;" the owner of the soil receiving a fifteenth part, or "dish,” of the
black tin raised within the "bounds." Before the tinner could establish any
right to those bounds, it was necessary that he should record his claim in the
Stannary books; and, unless appealed against, he had thenceforth a just
right to search for tin within such bounds as he had cut.
Pryce, in his "Mineralogia," gives us some important information as to
the quantity of tin raised at different periods, including especially the period
with which we have been dealing.
In 1471 the Duchy received, as profit, at 4s. per cwt.
In 1479 the amount of the coinage dues for Cornwall was
In 1524 the profits of Devon and Cornwall were
£1,705 0 5
£1,620 17 11
£2,771 3 93
(424 tinners in Devon paying in addition to coinage dues 8d. per annum for white rent to the Duke.)
In 1602 the tin coinage in Cornwall alone amounted to
£2,623 9 8
In 1558, and until 1603, Queen Elizabeth paid much attention to the
British mines. She sent to Germany, and obtained the services of a large
body of practical miners. These were dispersed over the various mining
districts of the kingdom, and they introduced a better system of mining, and
more perfect processes of dressing the ores. This was especially observable
in the machinery employed for dressing the ores of tin and lead.
During the seventeenth century the average of metallic tin produced was,
according to Pryce, 1,500 tons per annum. During the reign of Queen Anne
there appears to have been a great accumulation of tin. A stock of 5,000
tons of tin, equal to five years' consumption, hung on the market, and a great
deadness of trade continued until 1789, when the East India Company
became speculators. The speculation answered, and the demand rose from
500 tons per annum to 15,000 tons, the price advancing at the same time.
This will be the proper place to describe briefly the system of Bounding,
which was a peculiar feature of mining at one period, although now unknown.
Bounds were limited portions, or pieces of land, enjoyed by the owners
of them in respect of tin only, and they were established by virtue of an
ancient prescription, or liberty, for encouragement to the tin miners. They
were limited by holes cut in the turf, and the soil turned back upon the turf,
which is cut in form of a mole-hill, and directly facing another of the like
kind. These are called the corners of the Bounds. By drawing straight lines
from the corners, the extent of these Bounds is determined in like manner
as, in geometry, by drawing straight lines from three, or sometimes four,
points, the extent of a triangular or quadrangular superficies is known (Pryce).
The annexed plan of the North Downs Bounds (Fig. 8), as they existed
formerly upon the site of, or near the North Downs mine of the present
day, will convey a correct idea of the irregularity of the system of Bounding.
If the land is neither Bounded nor enclosed, but a wastrell or common,
then any one could mark out Bounds there, and claim the search for tin. The
Stannary Laws eventually insisted that "whoever intends to cut a Tin
CHAP. III.]
THE SYSTEM OF TIN BOUNDING.
53
Bound, must first give three months' notice of his intention in the Stannary
Court, and to the lord, for him to show cause, if he is so inclined, why it
should not be done."
It is exceedingly difficult to ascertain the exact time when Bounding was
first commenced. Probably it arose from the necessity of each miner marking
out his set, which was on the plan distinguished by the letters of the alphabet.
A Bounds book, dated on its vellum cover 1716, and labelled “ Hussey's
BOUNDS BOOK," having on its first page, "Mr. Francis Gregor's Book
of his Tyn Bounds, made the 2nd of January by us, 171, gives the
Σ
B
C
E
D
H
C
L
K
0
N
P
Fig. 9.-Plan of North Downs Tin-Bounds.
names and defines the situation of eighty-two Tin Bounds in St. Agnes and
Pyran Sands," has been placed in the author's hands.
From this book the following first four Bounds only have been copied, as
they will show very satisfactorily the irregular way in which those spots
of tin ground were divided.
NAMES OF
THE BOUNDS.
THEIR SITUATION AND BOUNDARIES
Speedwell.
Good
Fortune.
IN ST. AGNES.
I
In Polbreen Croft. Bounded on the South with Whealan-vor; on the East with a
little piece of Sevorall; on the North with the Four and Twenty paire; and on the West
with the little Whealan Culliack.
2
Bounded on the North with a little paire of Bounds belonging to Mr. Francis Gregor
and others; on the East with Speedwell; on the South with the little Whealan Culliack;
and on the West with Mr. Tonkin's Sevorall.
3
Bounded on the East with the little Whealan Culliack; on the West with Whealan
Preservation. Can the North with Good Fortune, and on the South with Whealan Bolster.
Crack; on
Prevention.
4
Bounded on the North with Speedwell; on the East with Whealan-vor; on the South
with the Great Whealan Culliack; and on the West with Preservation. Mr. Francis
Gregor in those four paire of Bounds last mentioned have two-third parts, and Francis
Bassett, Esqre., have the other third part, commonly called by the name of Polbreen
Bounds.
54
[BOOK I.
HISTORICAL SKETCH.
The following grant of certain Tin Bounds is interesting, as showing that
the descendants of Schutz, who was brought from Germany by Queen
Elizabeth, attained to a place of honour, and kept it as late as 1740:—
66
'John Schutz, Esquire, Lord Keeper and Warden of the Stannaries,
Chief Steward of the Duchy of Cornwall, and so forth, To the Bailiff of the Stan-
nary of Tywarnhaile, in the County of Cornwall, and also to Christopher Oates,
John Wills, and John Bawden, and every of the GREETING, Whereas Messrs.
Perry to the court held for the said Stannary of Tywarnhaile, at Truro,
within the said Stannary, the sixth day of October, in the fifteenth year of
the reign of our Sovereign Lord George the Second, by the grace of God of
Great Britain, France, and Ireland, King, Defender of the Faith, and so forth,
and in the year of our Lord one thousand seven hundred and forty-one,
Before Richard Hussey, gentleman, Steward of the said court, and gave
notice to the said court, That he had on the twenty-third of September last
past Cutt and paired one pair of Tin Mine Bounds (Void of all other lawful
bounds) called Wheal Coynt Bounds, lying and being in the parish of St.
Agnes, within the said Stannary, To the only use of James Donnithorne,
gentleman, The South West Corner of the said Bounds, lying at the corner
of Pitt's Hedge, joining with the corner of a mine croft or Wheal Burrow,
and Great Truslee the North West corner thereof, for about one hundred
yards south of Creegmore burrows, in the Downs. The North East corner
lyes about thirty yards to the North East of Trufla shop joining with Great
Trufla and Wheal Long, together with a North Side bound, or half corner
between the North West corner and Creegmore Burrow aforesaid, and join-
ing Wheal Burrow, containing about Ten Acres of Land, or ground, as by
the Bounds and Limits thereof will more plainly appear." Proclamation of
these Bounds is then prayed for, certain conditions are accepted, and the
document duly signed.
"E. R. COOKE, Attorney."
(With an addition which is not intelligible.)
"R. HUSSEY."
Another Deed, bearing date 1743, shows that THOMAS PITT, Esquire,
was then "Lord Keeper and Warden of the Stannaries, and Chief Steward
of the Duchy of Cornwall, and so forth." He issues "To the Bailiff of the
Stannary of Tywarnhaile, and also to Christopher Oates, John Wills, David
Jarba, and John Jarba "-forming the Court-his statement, "That Moses
Perry came to the Court held for the said Stannary of Tywarnhaile, at Truro,
within the said Stannary, &c. &c., Before Sampson Sandys, gentleman,
Steward of the said court, and gave notice to the said court, That he had on
the 18th day of July in the year of our Lord 1743, cutt and pitched one pair
of Tin Mine Bounds (void of all other lawful Bounds) called or known by
the name of Wheale Dower,"-one moiety or half of the said Tin Bounds,
To the use of James Donnithorne-one quarter part to the use of Benjamin
Nankivell the younger-and the other quarter part to the use of Anne
Trezise and Mary Trezise. The Bound Boundaries are then stated in the
usual manner, and certain covenants inserted, the document being signed by
SAMPSON SANDYS, Steward.
CHAP. III.]
THE BAILIFF OF BLACKMORE.
55
The endorsement states that this Writ has been duly delivered to those
above mentioned; to whom the Tin Bounds have been granted.
The following has been copied from Mr. J. S. Enys's "Bounds Book.”
Kept by Henry Tregellas. Beginning in 1765.
“I, Henry Tregellas, agent for John Enys, Esq., grant asset unto James
Martin of pts of a paire of Tyn Bounds, Called W¹ Drible or Driblewill,
and the Sª James Martin is to have Twenty fathom of Ground on the Course
of the Load or Loads he shall work on Condition of paying one Twelfe part
of all the Tyn he Shall Rise out of Sª pitch, at the Milting-house after
the Toll is first payd, and to give Twenty-four owers Notice to the Agent
Intrusted to go to Milting-house to Receve the Sª farm, but it is Farther
agreed with the Sª Henry Tregellas & the Sª James Martin that it Shall and
may be Lawfull for the Sª John Enys, Esq., or his agent at any time when-
ever they shall think proper to have the ninth pt powred, out on the grass,
whereby he may have his pt of the farm in the Stone, and to Grant Liberty
to the Agent to go Down Into Sª Mine, to Diel or measure the ground when
Ever he Shall think proper, and to work the Sª Mine according to the Last
act of Convocation, all which Above Conditions I the Sa Taker do agree to
perform, as witness my hand this 25th Day of Feby, 1767,
"Henry Tregellas Letter,
"JAMES MARTIN.”
The miners, in old times, appear to have enjoyed especial privileges:
they could search for tin or copper in all waste grounds, or Wasterall,
paying only a royalty to the Crown upon the ore they rose. In the
“Bailiff of Blackmore,”—a manuscript of authority by Mr. Beare—one of the
Stannators for Blackmore, we read: "That they," the tin miners, “always
used to worke and search for tynn in Waster all grounds, and also in the Prince's
Severall, where any tynne might be gotten; having likewise libertye to digge,
mine, search, make shafts, pitch bounds; and for tynne to work in places
of their most advantages; excepting only sanctuary grounde, churchyards,
mills, backhouses, and gardens; paying only to the prince or lord of the
soil the fifteenth part to and for the toll of their tynn.
>>
Mr. Gregor, a Vice-Warden of the Stannaries, states that he finds "that
the tinners wrought for their tin by custom, until the 33rd of Edward I.
(1305), which was sixty-four years after the Jews were banished, when they
(the miners) procured their charter, which was obtained at the solicitation of
the Lords of Trethuvy, Boswithy, Treverbyn, Prideaux, Trenans, Austell,
Tremedry, Tregarrick, and Milliack, who obliged their lands to pay assent,
and do service to the law courts erected by the charter."
We learn from Plowden, quoting "Pearce's Stannary Laws,” and from
Sir John Doddridge, that all tin was at first the possessionary right of him
who had the government of the country, and from whom, or from the King,
the liberty was granted immediately to the searcher.
Pryce remarks: "The first institution of those customary tenures, for the
encouragement of searching for tin, was laudable and wise; but the late (he
56
[BOOK I.
HISTORICAL SKETCH.
is writing in 1778) increase of tin and discovery of lodes, together with the
present improvements in mining, very much diminish the necessity of this
kind of encouragement. On the contrary, from very good reasons, I can
assert it would be well for this county in general if tin bounds were totally
obliterated."
Bounds are no longer known. Bounding has no existence in modern
times. A set of bounds for tin, though verbal, was perpetual, and never
ended while it was wrought according to the laws and customs of the
Stannaries. To preserve the right of a bounds, it was to be renewed once
every year, which was performed in different bounds on different Saints' days,
according to the parishes, by the servant of the lord, called the Toller, the
Renewer, or the Bounder. The renewal consisted really in putting more
earth upon the turf marking the original bounds, retiring to some house
of entertainment and eating a good dinner, to celebrate and commemorate
the annual renewing-day.
It was lawful for the bounder, or any other person to whom he had
granted liberty, to dig and search for tin, provided that he acknowledged
the lord's right by giving him a fifteenth part of the whole produce; then it
was lawful for the bounder to take out one-twelfth, or in some places
one-tenth, of the remainder.
Tinners were allowed to drive an adit for the passage of water only
through other bounds without liberty; but if they discovered tin, that mineral
was left wholly to the owners of the bounds within which it was found.
In 1697 a curious tract was published, from which we may glean some
important information. It bears the title "Aggravii Venetiani," &c.; or,
"The Venetian and other Grievances, together with a proposal for raising the
price of tin in the Counties of Cornwall and Devon, according to the Policy of
the Venetians, when they regained the Western Trade, which they had once
almost lost. Most humbly presented to the King's Most Excellent Majesty
(Charles I.), the Right Honourable the Lords Spiritual and Temporal.
"And to the Honourable the Commons of England in Parliament assem-
bled, and humbly offered to the Honourable Council appointed to inspect
the Trade of the Nation. London: Printed for Sam Crouch, in Cornhill;
Abel Roper, in Fleet Street; and Joseph Fox, in Westminster Hall, in 1697.”
This pamphlet deals chiefly with the sad difficulties which at the date
mentioned—the beginning of the seventeenth century-surrounded the currant
trade at Zante. Owing to the difficulties thrown in the way of this trade,
smuggling to an enormous extent was carried on. With these matters we
have nothing to do; but the second part, "The Proposal for raising the
Price of Tin," &c., immediately concerns us. The author commences: "Had
we, in the four last reigns, exemplified the policy of the wise Venetians to
encourage and promote our trade and commerce, being posted by nature on
the emporium of the world, and being a warlike people, what could we not
have done? A well-managed trade is the creator and preserver of money,
and money and trade are the sinews of war." He continues :—
"Cornwall (by the providence of God) doth naturally produce tin. A
mettal, when fine, is in its nature next to silver, and is said to have given the
name of Britain to this nation; which being consider'd, may ingage the
CHAP. III.] PROPOSAL FOR IMPROVEMENT OF TIN TRADE.
57
King's most excellent Majesty, as God's representative, and his High Court
of Parliament, to have the greater value and esteem for it.
"The county being environed as it is by the sea, and having the advan-
tage of good harbors, Nature seems to have designed it for a flourishing
trade; and the more, because that land not only abounds with the best tin
in the world, and the greatest quantities thereof, but the sea affords it the best
fish also.
"And abounding with tin and fish, as Zant doth with currants and wine,
as the Venetians have improved the trade of Zant, so we should use our
utmost endeavour to encourage and revive the trade of Cornwall.
"What prices tin bore, and what trades were driven thereby in Queen
Elizabeth's time, when we had the absolute empire of the ocean and a
flourishing trade, I cannot so well inform my reader as I would.
"But some years before the Restoration, when we had again the command
of the seas, that commodity of Cornwall yielded to the tinners there £6 5s.
a hundred merchants weight, clear of all coinage duties; and then the
income to that county (by that commodity only) amounted to £200,000
a year and upwards.
"The quantities of tin are now almost the same as formerly, only that
trade hath been, of latter years, mismanaged, to the great disadvantage both
of that county and the kingdom, the price of tin being now brought down to
50s. per cent. or thereabouts. For the Cornish factors are less kind to their
countrymen, the tinners, than our English factors are to the Zanteots; and
more faithful to the London pewterers, than those are to their English
principals. And (being no less careful for themselves) as our factors imploy
their merchants' capitals, to prevent and forestall those that imploy them;
so our Cornish factors imploy the stock, remitted to them by the pewterers,
in necessary materials for carrying on the tin trade, which materials they
sell at extraordinary rates to the labouring tinners, to be paid for the same
in tin, much under the market price. And having once got those people
into their debt, they do, by interest and extortion, always keep them so poor,
that (to gratify the London pewterers and merchants that imploy them, and
for another interest) they compel those poor tinners to sell at what price they
please, and by that means do govern the market not only to the great
detriment of the county, but to the disadvantage of the kingdom.
"Now the tin trade being divided into so many people's hands, as those
labouring, adventuring tinners are, it will be difficult to do them good, but
by a law enacted to redress their grievances, and such a law as (being
executed) may have the like effect with that of the novissima imposta, when
the Venetians had almost lost the Western trade. And we, having so far
lost our Western trade of tin, that the labouring tinners can scarce get
their bread, I am of opinion that we may regain it with advantage, and raise
the price of tin in some degree, if (after the precedent and example of the
Venetians) a novissima imposta be laid upon all such as shall buy and sell tin
in the counties of Cornwall and Devon, under three or four pounds a hundred,
or such a price as the King's Most Excellent Majesty, the Right Honourable
the Lords Spiritual and Temporal, and the Honourable the Commons in
Parliament, shall think meet. And tin being now at 50s. per cent., such an
58
[BOOK I.
HISTORICAL SKETCH.
imposition will be of considerable advantage to the nation, both in general
and in particular. At four per cent. (considering the present price) the King
will gain by the benefit and advantage of his subjects, altho' his Majesty
should have no more than his former duty. The kingdom will gain (accord-
ing to the present rate of tin) three parts in eight of all that is transported,
because the same quantity, being transported at that price, will occasion the
importation of three-eighth parts more in return, either in money or mer-
chandise; for all other markets are governed by the first market price.
"The county in general will gain by it, because land and trade are in
natural sympathy; and the tinners, having £4 a hundred for their tin, will
have the more money and credit to support themselves and their families.
"The Cornish factors will gain by it three-eighth parts in their provision,
if no more, and this will take away the occasion of grinding the poor to satisfie
the principals, &c.
"The London pewterers will have the like advantage, insomuch as they
are factors for Tin. And I have heard the chiefest of them wish that the
price of tin might never be less than £3 a hundred in Cornwall.
“And, after all, the principal merchants can be no losers by it, if it be
true what a certain merchant once wrote me at Zant, "That the dearer they
bought abroad, the dearer they sold at home." So that it is as much the
interest of the whole kingdom to keep up the price of tin in Cornwall, as it
was for the Venetians, the Zanteots, and the Praemorratory, to keep up the
price of currants at Zant.
"And that it may not be urged that the advancing the price of tin will
cause the less quantity thereof to be transported, I must here take notice,
that there is no part of the known world, besides Cornwall and Devon, that
doth produce tin, unless it be Germany and the East Indies; and the tin
which is made there is not so good as our tin by 20s. the hundred; nor can
they afford to sell the same so cheap as £5 per cent.
"Neither will the East India or German tin serve so well as ours, for the
very many uses which are made thereof throughout the world; and, not to
mention its excellent usefulness for making looking-glasses, lackering,
painting, &c., I am informed that the finest earthenware in the world
cannot be made without our Cornish tin, which occasions so great a con-
sumption of that commodity, beyond what is expended in all common uses.
And further, it hath been observed, that when the greatest quantities of tin
have been made in Cornwall, that there hath been none left uncoined or
unsold; and the higher the price, the better those qualities have gone off;
which (to me) seems a good argument of a necessity the world is under to
buy this commodity of us. And their necessity, as well as our great costs
and charges, and the danger and difficulty of coming at the tin, should bring
us to understand its true value, and make our utmost advantage by it; and
did we make but half the quantity of tin we now do, we might advance that
quantity to what price we pleased; and then the one-half of the charges
would be saved also.
"The charge of deals, cordage, and iron, which for the most part come
from Norway, the East Country, and Spain, and eat up a great part of the
profit, would then be but half as much.
CHAP. III.]
THE CORNISH TIN FACTORS.
59
"And one half of the labourers would be imployed in the fishing trade,
&c., and to improve the lands by husbandry, that county being capable
of improvement that way, to double the value it is now off, besides the
advantage that might be made by a full improvement of the fishery, &c.
"And now to show the deplorable circumstance of the poor labouring
tinners, we will suppose (for demonstration sake) there are eight thousand
tinners partly imployed about the tinning trade, although I am satisfied.
that they much exceed that number, who (with their families) depend upon
the product of their labour.
"And all the tin coined in Cornwall in the year 1692 (which was the year
before I designed to publish these grievances) was, by the coinage-books of
that county, 11,174 pieces, and the coinage duty thereof being 4s. a hundred
in Cornwall, amounted that year to £5,449 17s. By which it doth appear
that there must have been 27,249 cwt. of tin made that year in Cornwall only.
"And supposing that quantity sold at 50s. per cent., the whole product
of the tin, made in Cornwall in the year 1692, must then come to £69,222 10S.,
which is a sum much inferior to the £200,000 a year and upwards.
"Now out of this £69,222 10s. must be paid (clear of all charges), to the
bounder and lord of the soil, for toll and farm, about a fifth part of the whole,
which comes to £18,844 8s.*
"Which, being deducted out of the above said£69,222 10s., there will remain
clear to be divided among the said eight thousand tinners, but £40,338 os. 2d.,
which comes to £5 10d. and about a half-farthing to each tinner.
"And this is all each tinner hath to maintain himself and family, and for
his whole year's hard labour, not only underground, but under God knows
how many grievances.
"But indeed they have been the better able to bear them, as being the
most Herculean and stoutest men upon earth, and, for their most faithful
and loyal services, have the greatest privileges of liberty and property of
any people in the kingdom.
"For there are other grievances relating to the tin trade, which are,
almost if not altogether, as prejudicial as what hath been said.
"The Cornish factors, and others, are not the only causes of the poor
tinners' misery: the Cornish lawyers must come in for a share too.
For as
the factors grind the poor tinners to gratify the principal traders, and thereby
increase their commissions, &c., so the lawyer (upon the discovery of a rich
mine) (taking the advantage of the tinners' ignorance in the stannary laws,
they being not set forth and published in print) do use all means (by way
of pretended justice) to right those clients against the bounder, the landlord,
or their fellow-adventurers, when in truth it is in the main a contrivance to
* The charges of smiths' work, timber, ropes, and candles, we compute to each man
in a year about £1, which for eight thousand men is
•
And supposing the dressing and stamping to make every hundred of tin comes to
2s. 6d., it amounts, for the whole year's tin, to
The charges of refining that year's tin at £1 10s, the tide, computing one thousand
of tin, to be refined in each tide, comes to
The charges of carrying, and the expenses at the refining or blowing-house, at
IOS. the tide, comes to
The whole sum to be deducted comes to
犬 ​s. d,
8,000 o o
3,206 2 6
2,725 7 O
908 12
4.
£14,840 I 10
60
[BOOK I.
HISTORICAL SKETCH.
make themselves masters of those mines, and the profits thereof, and the
tinners the slaves only to dig the oar for them.
"And this they the sooner do, because their fees are so great, and the law
suits (which they create) so dilatory that (in proportion) they exceed all
other grievances, whereas the tinner's privilege (as I am informed) is to have
their proceedings at law altogether in English; and, upon payment of a
penny only, they are at liberty to appear in person, and to speak and act
for themselves, that their causes may be the sooner ended.
"Upon the whole, it may be said that it is with the tinner and his tin, as
it is with the Spaniard and his silver; and indeed the tinner takes all the
pain, and others carry away the profit.”
Thus ends the best information we possess of the grievances of the Cornish
tinners at a time when tin mining had reached its lowest condition.
Mr. Scawen, of Millin-ike,* Vice-Warden of the Stannaries in the time
of Charles II., complains that the revenues from tin were very small. They
remained so until the eighteenth century, the block tin, produced annually
up to 1713, being never more than 1,600 tons.
In 1730 the tin-plate manufacture was established, and this gave an
impetus to the tin trade. The manufacture of tin plate is so directly con-
nected with the progress of tin mining, that a few lines must be devoted to
its history.
The manufacture of tin plate existed in Bohemia in 1620, and had been
known in that country for many years. The process of tinning iron had been
kept very secret. Nearly all the tin-plate works were in the hands of the
reigning duke, and consequently the methods were carefully guarded. The
secret was said to have been brought to England in 1670, but Réaumur,
writing in 1725, says: “It is said that it (tin plating) was kept a secret
there (in Bohemia) very carefully; but where is the country, and which is the
trade, where workmen are not mysterious!" An Englishman is said to have
visited Saxony in 1605, and to have found many flourishing manufactures
there. It was, however, about the year 1625 that eleven English gentlemen
found the money which enabled Mr. Andrew Yarranton to visit Saxony, for
the purpose of acquiring some exact knowledge of the manufacture. He is
said to have been accompanied by an able fireman who understood the
nature of iron. With an interpreter they visited Dresden, and were well
received. Yarranton certainly gained much knowledge of the manufacture,
for, returning to England, he made many parcels of tin plate, which were sent
to London and to Worcester, "And all workmen that wrought upon them,
agreeing that the plates, and the metal they were made of, was much better
than those plates which were made in Germany, and would work more
pliable, and serve for many more profitable uses than the German plates
would do. Upon which preparations were made to set this beneficial thing
at work for the improvement of our own minerals and setting the poor at
work." The first attempt to manufacture tin plates was made at the
village of Pontypool, in Monmouth, by Major John Hanbury, in 1720.‡
* Signifying Mill-Lake, in the parish of St. Germans.
+ See "England's Improvement by Land and Sea." By Andrew Yarranton. 1698.
Į "A History of the Trade in Tin," &c. By Phillip William Flower. 1880.
CHAP. III.]
THE PRODUCTION OF TIN.
61
This new manufacture considerably improved the condition of the tin
mines of the west; but war being declared in 1744, the means of transport-
ing tin by sea to London was stopped. About this time a "committee of
gentlemen was formed to consider a proposal made by the Society of
Mines Royal, to farm the tin for seven years.
"
From this report we learn that the prices per cwt. for grain tin was £3 9s.,
and for block tin £3 5s. Sir John St. Aubyn, who was very active, obtained
from the Admiralty a convoy for the tin ships, and he warned the tinners
not to sell in Cornwall at £50 per ton, since Cleeve, a London merchant,
would give £60. In 1746 this price was still maintained, and the quantity
raised per annum was still increasing. In 1748, Mr. William Lemon informs
us that 2,329 tons of block tin had been produced, the price being £64, while
nine years later the quantity had increased to 2,595 tons, but the price had
fallen to £59. From this date to 1758 the estimated value was £180,000.*
Notwithstanding what has been already said in respect to the progress of
the tin trade, and of the various matters incidental thereto, it appears
desirable that some description should be given of the mode adopted by the
miners of the last century in obtaining and in smelting their tin, and a
statement made of their views respecting the origin of that metallic
treasure.
Carew, in the "Survey of Cornwall," 1769, thus describes the ideas pre-
valent with the Cornish miners, as to the mode of the occurrence of tin, and
the methods of search adopted by them: "The Cornish Tynners hold a
strong imagination that in the withdrawing of Noah's flood to the sea, the
same took his course from east to west, violently breaking up, and forcibly
carrying with it the earth, trees, and rocks, anything which lay loosely
near the upper face of the ground. To confirm the likelihood of which
supposed truth, they do many times digge up whole and huge timber trees,
which they conceive at the Deluge to have been overturned and whelmed,
but, whether then or sithence, probable is, that some such cause produced
the effect. Hence it cometh, that albeit the tynne lay couched at first in
certaine strakes amongst the rockes, like a tree or the veins in a man's body,
*MS. letters to Dr. Borlase, and from Mr. W. Lemon, quoted by Mr. W. C. Borlase in his
"Historical Sketch of the Tin Trade."
NOTE ON THE PRODUCTION OF TIN.
Mr. Scawen, of Millin-ike, was Vice-Warden of the Stannaries.
James I. and The amount of Block Tin yearly was from
Charles I.
}
Queen Anne ? One year with another amounted to something more than
and George I.j
In 1742.
In 1778.
A proposal was made by the Mines Royal Company in
London to raise £140,000 to encourage the tin trade by farm-
ing that commodity for seven years at a certain price. A
committee of Cornish gentlemen were appointed to consider
the proposals. They reported "That the quantity of tin raised
yearly in Cornwall, at an average for many years last past,
hath been about
•
"And resolved that £3 9s. for grain tin, and £3 5s. per
hundred weight for common tin, are the lowest prices for
which such tin will be sold to the contractors, exclusive of all
coinage, duties, and fees.”
Pryce says, "We have coined in one year
For the last twenty years, the annual average has been about
1,400 to 1,600 tons.
1,600,,
2,100,
3,600,
99
3,000,,
62
[BOOK I.
HISTORICAL SKETCH.
from the depth whereof the maine load spreadeth out his branches until they
approach the open ayre, yet they have now two kinds of tynne workes,
stream and load; for (they say) the foremencioned flood carried together with
the moved rocks and earth so much of the load as was inclosed therein, and
at the asswaging left the same scattered here and there in valleys and ryvers
where it passed, which being sought and digged is called stream worke ;;
under this title they comprise also the Moore works, growing from the like
occasion." They maintain these works to have been verie ancient, and first
wrought by the fewes with Pickaxes of Holme, Boxe, and Hartshorne.
They proove this by the name of those places yet enduring, to wit, Attall
Sarazin, in English the fewes' Offcast,* and by those tools daily found
amongst the rubble of such works. And it may well be that, as Akornes
made good bread before Ceres taught the use of corne, and sharp stones
served the Indians for knives before they obtained them in iron, so in the
infancie of knowledge these poor instruments, for want of better, did supplie
a town." t
The following passage, from a much more recent author, shows that
similar ideas prevailed in his time (1811) as were common in the time of
Carew: "The peculiar situation," observed Mr. Joseph Carne, "in which
nearly all the stream tin of Cornwall is found, compared with the localities
of the most productive tin veins, is highly illustrative of the direction in which
the current of the Deluge swept over the surface. All the productive streams
are in the valleys which open to the sea on the eastern side of the Cornish
peninsula, whilst most of the richest veins are situated near the northern
coast, where all the valleys open towards the north. Most of these valleys
have been explored, but although small portions of tin have been found in
many of them, no extensive beds have ever been discovered. The mines,
for instance, of the parishes of Lelant, Gwinear, Camborne, Illogan, St.
* "As for the name of the castaways, Attal Sarazin, it does not signify the Jews' offcast, but the leaving
of the Saracens, as Mr. Camden truly observes in his 'Britannica,' and from thence infers that the
Saxons (who had never, that I can find, any firm footing in the country) seem not to have meddled with
them, or at most to have only employed the Saracens (if they did mean, saith Holland's interpolation, by
that means the ancient Panyms), so that this seems to have been the more modern name, which is now
quite disused; and these old works are now called by their more ancient name, Wheal an Jethewon, or
Works of the Jews; whose aqueducts, levels, &c., are to be seen all over those parts of the country where
tin is found, as particularly in St. Piran in the Sands, St. Agnes, &c. So that it is very probable, as Mr.
Carew says, that these Jewish workmen were brought over here by the Flavian family, after the destruc-
tion of Jerusalem, and their general dispersion."-Carew's "Survey of Cornwall." De Dunstanville's
edition (1811).
+ In Carew's "Survey of Cornwall," to which are added notes, illustrative of its history and anti-
quities, by the late Thomas Jenkins, Esq., and now first published by Francis, Lord de Dunstanville, 1811,
we find the following:
"The opinion of Noah's flood taking, as it withdrew, its course from east to west, has no other founda-
tion than from all or most of the tin veins or loads running from east to west throughout the country; for
which some would give a philosophical reason.”
"It is likewise almost certain, that tin was first sought for in the stream works, as the prodigious
working throughout the country of that kind, and the nature of the thing, do pleasingly show. And on
the failure of the streams, they were forced to have recourse to the load or meine (i.e. the rock or stone)
as they call it.
"Besides these ancient stream works, which are now very much worn out, we have another sort of
them, occasioned by the refuse and leaving of the stamping-mills, &c., which are carried by the streams
down to the lower grounds, and after many years lying, necessary to consume the mixture of bad metal and
poder (as they call it), viz. mundick, copper, &c., yield very good profit to the adventurers, whom they
call by a particular name sappiers.
Of late years, those lowlands and sands under St. Piran,
Arwothal, covered almost every tide with the sea, have, on its going off, employed some hundreds of poor
men, women, and little children, incapable of otherwise earning their bread, and turned to very good
account to the neighbouring inhabitants. The lowlands also under St. Blazey and Tywardeath."
CHAP. III.]
THE DISCOVERY OF TIN MINES.
63
Agnes, and Perranzabula, are all near the northern coast, but there are no
productive streams in any of those parishes. On the southern side, however,
are the streams of Perran-Arworthat, Ladock, St. Stephens, Roche, St.
Austell, Luxillian, &c. Now, on looking at the direction which the streams
bear from the mines, it will appear most probable that the course of the
current which swept the tin from its original situation must have been from
north to south, or rather from N.N.W. to S.S.E."*
To return to Carew, he continues: "There are also taken up in such
works certaine little tooles, heads of brasse, which some terme thunder axes
(celts), but they make small show of any profitable use. Neither were the
Romans ignorant of this trade, as may appear by a brass coyne of
Domitian's found in one of these works, and fallen into my hands; and
perhaps under one of those Flavians, the Jewish workmen made here their
first arrivance. They discover these workes by certain tynne stones.
lying on the face of the ground, which they term shoad, as shed from the
main load and made somewhat smooth and round by the water's wash
and wearing. Where the fynding of these affordeth a tempting likelihood,
the tynners go to work casting up trenches before them, in depth 5 or 6
foote, more or lesse, as the loose ground went, and 3 or 4 in breadth,
gathering up such shoad as this turning of the earth doth offer to their
sight. If any ryver thwart them, and that they resolve to search his bed,
hee is trained by a new channel from his former course. This yieldeth a
speedie and gainful recompense to the adventurers of the search, but I hold
it little beneficial to the owners of the soil.
"To find the load workes, their first labour is also employed in seeking this
shoad, which either lieth open on the grasse, or but shallow bye coursed.
Having found any such, they conjecture by the sight of the ground which
way the flood came which brought it thither, and so give a guess as to the
place wherever it was broken off. There they sincke a shaft or pit of five or
six foot in lengthe, two or three foot in breadth, and seven or eight foot in
depth, to prove whether they may so meete with the load. By this shaft they
also discerne which was the quicke ground (as they call it) that mooved
with the flood, and which the firm, wherein no shoad doth lie. If they miss
the load in one place they sincke a like shaft in another beyond that, com-
monly farther up towards the hill, and so a third and fourth, until they light
at last upon it.”
After some irrelevant matter on the question of the "tynne groweth,"
which Carew does not entirely believe, he continues: "The colour both of
the shoad and load resembleth his bed, as the sea-sand doth the cliffes, and
is so diversified to reddish, blackish, duskie, and such other earthly colours.
If the load wherein the tynne lieth carrieth a foote and a half in breadth and
be no overbarriers, it is accompted a verie rich work, but commonly the
same exceedeth not a foote, unless many loades occurre together. When
the new found work intiseth with probabilitie of profit, the discoverer
doth commonly associate himself with some more partners, because the
charge ammounteth mostly verrie high for any one man's purse, except lined
beyond ordinary, to reach unto; and if the worke doe fail, many shoulders
"Trans. Geol. Society of Cornwall," vol. iv. p. 110.
64.
[BOOK I.
HISTORICAL SKETCH.
will more easily support the burthen. These partners consist of either such
tinners as worke to their owne behalf, or such adventurers as put in hired
labourers. The hirelings stand at a certain wages, either by the day, which
may be about eightpence, or for the yeare, being betweene four and six
pounds, as their deserving can drive the bargains, at both which rates they
must find themselves. If the worke carrie some importance and requires
the travaile of many hands, that hath his name, and they their overseer,
whome they terme their captaine, such as the Pel, Whilancleuth, in English,
The Worke of the Ditches; Pulstean, that is, The Myrie Head; Cruegbraaz,
The Great Borough; Sanit Margets, and many surnamed Balls, which
betokeneth the vales where the works are set on foote."
The duties of the captain-" setting the taskes," "binding the workes,"
placing the pumps, &c., are then fully given. "In most cases," continues
Carew," their toyle is so extreeme, as they cannot endure it more than above
four hours in a day, but are succeeded by spells; the residue of the time,
they weare out at Coytes, Kayles, or like idle exercises. Their kaylender also
alloweth them more holydayes than are warranted by the Church, our lawes,
or their own profit."
"Their ordinary tooles are a pickaxe of yron, about sixteen inches
long, sharpened at one end to picke, and flat-headed at the other to
drive certaine little yron wedges wherewith they cleave the rockes. They
have also a brood shovell, the utter part of yron, the middle of timbre, into
which the staffe is slopewise fastened. (See Fig. 5, p. 30.)
"Their manner of working in the load mines is to follow the load
as it lieth, either sidelong or downe-right: both ways the deeper they
sink the greater they find the load. When they light upon a small veine,
or chance to leese the load which they wrought, by means of certaine
strings that may hap to cross it, they begin at another place near at
hand, and so draw by gesse to the main load again. If the load lie right
downe they follow it sometimes to the depth of fourtie or fiftie fathom.
These load works, Diod. Sic. l. 5, cap. 8, seemeth to point at where, he saith,
that the inhabitants of Velerium Promontine digge up tin out of rockie
ground. From some of their bottoms you shall at noonedayes discrie the
starrs; * the workmen are let down and taken up in a stirrup, by two men who
would winde. If the load lie slopewise, the tynners digge a convenient
depth, and then passe forward under ground so far as the ayre will yield
them breathing, which, as it begineth to faile, they sincke a shaft down
thither from the top to admit a renewing vent, which, notwithstanding, their
work is most by candlelight. In these passages they meete sometimes with
verie loose earth, sometimes with exceeding hard rockes, and sometimes with
great streams of water. The loose earth is propped by frames of timber work.
as they go, and yet now and then falling downe, either presseth the poore
workmen to death, or stoppeth them from returning. To part the rockes they
have the foremencioned axes and wedges, with which mostly they make
speedie 'way, and yet (not seldome) are so tied by the teeth as a good work-
man shall hardly be able to have three foot in space of so many weeks.
* This proves that the early miners must have worked to a greater depth than it is usually supposed
they were capable of doing.
CHAP. III.]
THE MODE OF WORKING TIN.
65
While thus they play the mold warps, unsavorie damps doe here and there
distemper their heads.
"(Addit).—They cal it the bringing of an addit or audit when they begin
to trench without, and carrie the same throw the ground to the tyn worke
somewhat deeper than the water doth lie, thereby to give it passage away.
This addit they either fetch athwart the whole load or right from the branch
where they worke, as the next valley ministreth the fittest opportunitie for
soonest cutting into the hill; and therefore a gentleman of good knowledge
deduceth this name of addit-Ab aditu ad aquas. Surely the practice is
cunning in device, costly in charge, and long in effecting, and yet, when
all is done, many times the load falleth away, and they may sing with
Augustus' bird, Opera et impensa perriit.”
Carew pursues his subject to the "Maner of dressing" and "crazing"
and "washing," and on to "melting." "We will now procede," he writes,
"to take a view of the orders and customes most generally used by the
tynners. Their workes, both stean and load, lie either in severall or in
wastrell, that is, in enclosed grounds or on commons." These terms were in
law as follows:
"In severall no man can search for tin without leave first obtained
from the lorde of the soile, who, when any myne is found, may worke it
wholly himself, or associate partners, or set it out at a farme certain, or leave
it unwrought, at his pleasure.
"In wastrel it is lawful for any man to make trial of his fortune that
way, provided that he acknowledge the lorde's right by sharing out unto
him a certaine part which they call toll: a custome savouring more of
indifferencie than the tynners' constitutions in Devon, which inable them to
digge for tynne in any man's ground, inclosed or unclosed, without license,
tribute, or satisfaction. The wastrel works are reckoned amongst chattels,
and may pass by worde or will." Of the rules of sharing, Carew says:—
"Doles, or shares, they make thereof, and proportionably divide the
gains and charges. The lorde of the soyle is most-where allowed libertie to
place one workman in everie fifteene for himself, at like hand with the
adventurers, if he be so disposed." And of measures he says:—
"They measure their black tynne by the gill, the topliffe, the dish, and the
footc, which containeth a pint, a pottel, a gallon, and towards two gallons.”
The tin miner, having obtained his masses of tin ore, whether large or
small, took them to the "stamping mill," by which they were broken, and
"How-
then to the "crazing mill," where they were reduced to a fine sand.
ever," says Carew, "of late times they mostly use wet stampers, and so
have no need of crazing mills for their best stuffe, but only for the crust of
their tayles." The following passage, giving several examples of the
rudeness of the processes adopted in Carew's time, is copied at length:-
"The stream, after it hath forsaken the mill, is made to fall by certain
degrees, one somewhat distant from the other, upon each of which, at every
discent lyeth a green turfe, three or four feet square and one foot thick. On
this the tinner layeth a certain portion of the sandy tinne, and with his
shovell softly tosseth the same to and from, that, through this stirring, the
water which runneth over it may wash away the light earth from the tinne,
F
66
[BOOK I.
HISTORICAL SKETCH.
which, of a heavier substance, lyeth faste on the turff. Having so cleaned
one portion, he setteth the same aside and begineth with another, until his
labour take end with his taske. The best of those turfes (for all sorts serve
not) are fetched about two miles to the eastward of St. Michael's Mount,
where, at low water, they cast aside the sand and dig them up: they are full
of rootes of trees, and on some of them nuts have been found, which con-
firmeth my former assertion of the sea's intrusion. After it is thus washed,
they put the remnant into a wooden dish, broad, flat, and round, being about
two foot over, and having two handles fastened at the side, by which they
softly shogge the same to and fro in the water between their legges, as they
sit over it, until what's over of the earthie substance there was left be flitted
away. Some of later time, with a sleighter invention and lighter labour, doe
cause certain boys to stir it up and down with their feet, which worketh the
same effect; the residue of this often cleaning they call 'black tynne,' which
is proportionably divided to everie of the adventurers, when the lord's part
hath been first deducted upon the whole.
“Then doth every man carry his portion to the blowing-house, where the
same is melted with charcoal fire blown by a great pair of bellows moved
with water-wheele, and so cast into pieces of a long and thicke squareness,
from three hundred to four hundred pounds weight, at which time the
owner's marke is set thereon." Carew then wastes many words of con-
dolence on the tinners, and expresses his wonder that "any gaine could
traine men to undertake such pains and perile." He then continues: “ 'During
the tinne thus melting in the blowing-house, divers light sparkles thereof are,
by the forcible wind which the bellows sendeth forth, driven up to the thatched
roof. For which cause the owners doe once in seven or eight years burn
those houses, and find so much of this light tin in the ashes as payeth for the
new building, with a gaineful overplus. A strange practice (certes), for thrift's
sake to set our house on fire. Others do frame the tunnels of the chimnies
very large and slope, therein to harbour those sparkles and to save the
burning. This casualtie may bee worth the owner some ten pounds by the
year or better if his mill have store of sutors. But sithence I gathered
sticks to the building of this poor nest, Sir Francis Godolphin (whose kind
helpe hath much advanced this my playing labour), entertained a Dutch
mineral man, and taking light from his experience, but building thereon
farre more profitable conclusions of his own invention, hath practised a more
saving way in these matters, and besides made tynne with good profit of that
refuse which the tynners rejected as nothing worth.”
The following note on the "History of Mining," and especially of the
"old men's workings," is of interest: "On the granite bosses of Cornwall,
especially at Wendron and St. Just, most of the lodes appear to have been
discovered and worked a long time back; the remains of the workings mark
the course of the lodes, and the lodes may be traced by these workings on their
backs, called the 'old men's workings.' The land appears to have been searched
very closely, as almost every tin lode has been thus worked on, done by
cross-teening (cos-teaning), sinking shallow pits, on the surface, and observing
the shoad stones beneath the soil. These lodes are worked to such a depth
as the miners could go without machinery, and the tradition at Wendron is
CHAP. III.]
THE INTRODUCTION OF GUNPOWDER.
67
that the water and tin stuff were drawn up by kibbles. There is a little mine
about a mile south of Carn Menelez Hill where the old men worked down
thirty fathoms, where the water now requires a steam-engine, 40-inch cylinder,
with a plunger 7 feet stroke and 11 inches diameter, making five strokes a
minute, to keep the water-144 gallons a minute (area 95 inches, equal to
144 gallons a minute). The tradition of the neighbourhood is, that before the
introduction of the steam-engine, about 150 kibbles were at work there
drawing water and tin stuff, and this, from the present amount of water,
appears to be about the quantity of labour required. The old men'
seem to have hunted up the whole country for tin lodes, and worked as
far as practicable with their means."-N. WHITLEY.
<
The period at which the use of gunpowder was introduced into our mines
has been a subject of much dispute. Mr. Hawkins thinks that it cannot be
traced higher than the beginning of the last century, or a century later than
its invention in Germany. Mr. Davis Gilbert, in 1792, states that he
believes gunpowder to have been introduced by the Germans in the eastern
mining districts of Cornwall. One old man informed Mr. Gilbert that it
was first used in the district of Leland, Zennor, and St. Ives, about ninety
years previously (i.e. 1700), by two men who came from the east, named Bell
and Case, and that they affected to keep their operations a secret, suffering
no one to see them charge the holes.*
I have been favoured with the following extract from an old register in the
parish of Breage, which fixes the period more decidedly.
"Thomas Epsly, senior, of Chilchumpton, parish of Bath and Wells in Somersetshire, he was the
man that brought that raree invention of shooting the rocks, which came here in June, 1689, and he died
at the ball, and was buried at Breag the 16th day of December, in the yeare of our Lord Christ 1689.
"A correct extract from an old Breage Register.
EDW. W. PRIDMORE,
"Vicar of Breage."
Mr. Thomas Tonkin, who added numerous notes to Carew's "Survey of
Cornwall," writing July 9th, 1733, says: "When they meet with rocks and
very hard ground, as sometimes they do, with such as require not only three
weeks, but three months, to hew so many feet through the same, they
formerly burnt furze and faggots, &c., to break the rocks; but that proving
insufficient, and very often fatal to the workmen, by the sudden change of
wind, which drove down the smoke upon them and suffocated them, they
have of late had recourse to gunpowder, by boring holes in them, in the nature
of mining of towns besieged. But this device has been likewise attended with
many sad accidents, by the powder taking fire too soon by a spark struck
from the rod in driving; which hath of late been much remedied by a method
introduced from abroad by Major Joseph Sawle, as used in the mines in
sieges: and that by not using of any rod, but by covering the powder and
fuse with fine earth, which answers full as well as if the stupple was
rammed in.”
From this it is evident that gunpowder was but very little used in
Tonkin's time, although it is clear that Epsly, a working miner, introduced
it to the mines in Cornwall forty-four years before Tonkin wrote.
Mr. Pryce states that he saw a note from Mr. Scawen, as Vice-Warden
of the Stannaries, in which he complained, as we have already stated,
* "Transactions of the Royal Geological Society of Cornwall."
F 2
68
[BOOK I.
HISTORICAL SKETCH.
that the tin revenues were small. This was only a temporary depression,
for in the reigns of James I., about 1620, and Charles I., about 1630, the
amount of block tin yearly was from 1,400 to 1,600 tons. It was also found
by the last two farms in Queen Anne's reign (about 1710), and the beginning
of George I.'s (1715), that block tin, one year with another, amounted to some-
thing more than 1,600, so that in the space of 110 years its mean proportion
was equal to 1,500 tons per annum. Since that time a gradual increase for
thirty years followed. In 1742 a proposal was made by the Mines Royal Com-
pany in London to raise £140,000 to encourage the tin trade, by farming that
commodity for seven years at a certain price. A committee of Cornish gentle-
men were appointed to consider the proposals, and they reported “that the
quantity of tin raised yearly in Cornwall, at any average for many years last
past, hath been about 2,100 tons; and resolved that £3 9s. for grain tin, and
£3 5s. per hundred for common tin, are the lowest prices for which such
tin should be sold to the contractor, exclusive of all coinage duties and
fees."
Pryce says, 1778: "It is a fact that we have coined 3,600 tons of block
tin in one year, and for the last twenty years the annual average has
been about 3,000 tons, which is double the quantity coined annually but
sixty years ago, and one-third increase for the last thirty."
As, with the close of the eighteenth century, the practice of "streaming
for tin" was gradually passing away, from the exhaustion of the alluvial
deposits, this appears to be the proper place to introduce some examination
of the conditions under which this stream tin was found.
The accumulation of gravels in the valleys of Cornwall, and in many of
the slighter depressions on the widespread moors of the county, and on the
side of hills, all show that the powerful action of water in the state of flood
has led to this distribution of detrital matter. There cannot be a doubt but
that all the stanniferous gravels have been derived from the decomposition
of the rocks situated in the higher grounds, and that their present position
is due to the influence of torrents. Sir Henry de la Beche says: "If we
regard the surface of Cornwall, in which a crust of decomposed or disinte-
grated rock now exists, one arising from the action of atmospheric influences,
and imagine a body of water to rush violently over it, carrying this disin-
tegrated or decomposed surface before it down to the present valleys, stream
tin would be found in them, much as it has been hitherto discovered, though
not perhaps so abundantly, if we infer from the present mode of occurrence
of tin ores so comparatively near the surface in many lodes, that a previous
surface, now removed, may have been still richer with respect to this metal
than that which we now find."*
It appears in St. Agnes, a district remarkably rich in stanniferous
deposits, that the evidences of dislocation, of slides and heaves in the mines
of Penhalls and Wheal Kitty, distinctly prove that many hundred feet of
matter have been removed from the surface. Indeed, the indications of
denudation over all parts of the western peninsula are obvious, from
Dartmoor to the Land's End.
"Report on the Geology of Cornwall, Devon, and West Somerset." By Henry T. de la Beche,
F.R.S. 1839.
CHAP. III.]
THE WORK OF A TIN STREAMER.
69
Those who have studied the decomposed Granite near St. Austell,
traversed as it is by a multitude of branches and strings of oxide of tin,
would have little difficulty in perceiving that if a body of water were made
to rush over it, the decomposed Granite would be readily removed, and that
the broken up strings and branches of tin ore would be rolled into pebbles
and distributed, just as the stream tin now occurs, down the valleys in the
neighbourhood. The specific gravity of stream tin varies, according to its
purity, from 5'6 to 6'9.
The specific gravity of Granite is from
Argillaceous Slate and Grauwacke,
Schorl rock
Quartz
Felspar
Mica
"
""
""
•
2.62 to 2.74
•
2.64 2.81
2.86
2.63
2.53,, 2.60
2.64
The following is an abstract from Pryce: Tin stones must come to rest,
from the diminished velocity of the water, long before any of the other materials
do so. When, therefore, the transporting water can no longer carry tin stones.
onwards, it will be capable of pushing forwards, or of retaining in mechanical
suspension, the other gravel associated with it, so that a fundamental layer
of tin-stone pebbles might be accumulated at the bottom of a valley and
remain settled, while lighter bodies were driven or carried forward, or driven
over it, due allowance being made for the forms and volumes of the com-
ponent parts of the whole transported detritus, iron-stone pebbles included.
Streaming, or washing the deposits in the valleys, or hollows, and sepa-
rating the heavy oxide of tin, black tin, from the pebbles or sand with
which it is mixed, is a simple operation. It was, without doubt, at one time
the only method by which the Cornish tinner obtained the valuable metal
with which he traded with the merchants of Tyre and Sidon. When it was
found that the débris to which attention was at first given had been derived
from the rocks, naturally the miners began to search the cliffs, where there
were any indications of any metal, and hence we find in some districts the
rocks have been pierced with numerous holes, the oldest example of mining
left to tell us of the operations of the "Old Men." Pryce continues :
"When a 'Stream Tinner' observed a place favourable in situation, he took
a lease, commonly called a sett, of the landowner, or lord of the fee, for such
a spot of ground, and agreed to pay him a certain part, clear of all expense,
in black tin-that is, tin made clean from all waste and ready for smelting.
The consideration was generally one sixth, seventh, eighth, or ninth, as was
settled between them; or, instead thereof, he contracted to employ so
many men and boys annually in his stream works, and to pay the land-
owner for liberty, from twenty to thirty shillings a year for each man, and
so in proportion for every boy; that is, for twelve shillings monthly wages,
he articled to pay the lord half as much as for a man.
"He then sank a hatch (shaft), three, five, or seven fathoms deep, to the
rocky shelf or clay, on both of which in the same valley the tin was frequently
stratified, without any difference in its being more abundant in one than the
other. It is found in different places, at various depths, and sometimes.
stratified, between what is called a first, second, or third shelf. . . . The
stratum of stream tin may be from one to ten feet thickness or more; in
70.
[BOOK I.
HISTORICAL SKETCH.
breadth from one fathom to almost the width of the valley; and in size from
a walnut to the finest sand, the latter making the principal part of the
stream, which is intermixed with stones, gravel, and clay, as it was torn
from the adjacent hills.
"When he sank down to the tin stratum, he took a shovelful of it and
washed off all the waste, and from the tin which was left behind upon the
shovel, he judged whether that ground was worth the working or not. If it
was 'proving work,' he then got down to the lowest or deepest part of the
valley, and dug an open trench, like the tail or low slovan of an adit, which
was called a level, taking the utmost care to lose no leads in bringing it home
to the stream. This level served to drain and carry off all the water and waste
from the workings, in proportion as there was a weak or powerful current of
water to run through it. Some places might have been very poor, and not
worth the expense of working; others again very rich, and thence called
Beuheyle or Living Stream, as was most commonly the case if it were of a
grouan nature, which, being more lax and sandy, was more easily separated
from its native place, or lode, and therefore more abundant and rich in
quality according to the known excellence of grouan tin.
"In the latter case the streamer carried off what was called the over-
burden, viz. loose earth, rubble, or stone, which covered the stream, so far and
so large, as he could manage with conveniency to his employment. If in the
progress of his working he was hindered, he teemed (or laded) it out with a
scoop, or discharged it by a hand pump; but if those simple methods were
insufficient, he erected a rag-and-chain pump, so called, or if a rivulet of water
were to be rented cheaply at grass (i.e. at the surface), he erected a water-
wheel with balance bobs, and thereby kept his workings clear of superfluous
water by discharging it into his level: meanwhile his men dug up the
stream tin and washed it at the same time, by casting every shovelful of
it, as it rose, into a tye, which was an inclined plane of boards for the water
to run off, about four feet wide, four high, and nine feet long, in which, with
shovels, they turned it over and over again under a cascade of water, that
washed through it and separated the waste from the tin, until it became half
tin.
"Though there was little dexterity in this manoeuvre, yet care was requisite
to throw off the stent, or rubble, from the tye to itself, whilst another picked
out the stones of tin from the garde, or smaller pryany part of it. During
this operation, the best of the tin, by its superior gravity, collected in the
head of the tye directly under the cascade, and by degrees became more
full of waste as it descended from that place to the end or tail of the tye,
which was not worth saving. If there was a copious stream of water near
at hand, they cast the refuse into it, by which it was carried so far as to
make its exit into the sea. After the tin was thus partly dressed in raising
it, they carried it to grass, and when a competent quantity had been col-
lected they proceeded to dress it for blowing (i.c. for smelting in small black
furnaces which are called blowing-houses').
<
“There are several ways of dressing this kind of tin; but the general
method is to make what they call a Gounce, which is nothing more
than a small tye, and what in mining parts is called strêke, in which the
CHAP. III.]
ANCIENT SMELTING OF TIN.
71
smaller tin is washed over again, as was done before in the tye, but with a less
current of water and a larger degree of care and caution, lest the tin be
carried off with it. The richer part of the tin lies nearest the head of the
gounce, which is carefully taken up, divided, or kept separate, according to
its goodness, and put into large vats, or kieves; while the waste that lies in
the hinder part of the gounce is dressed over again, till all the tin is taken
out, and the remaining waste becomes absolute refuse. The tin is then
sifted through wood or wire sieves, whereby the greater particles are divided
from the smaller. By this method, likewise, the waste from its levity lies
uppermost in the sieve, which is carefully skimmed off and laid aside to
work over again. The smallest tin which passes through the wire sieve is
put into another finely woven horsehair sieve called a Dilluer, by which,
and the skill of the workman, it is made merchantable. Some of the
nodules, or lumps of tin, are blown or smelted as they come out of the tye,
but those which are mixed with waste are put with the refuse of the garde and
poor tin, which were in the tails of the tye and gounce, and being sent to
the stamping-mill are triturated and pulverised, so that all waste may be
cleared from the tin by sundry ablutions, the same as are performed in the
dressing of mine tin.
"Stream tin, being prepared and made ready for blowing with a charcoal
fire, is carried to the blast furnace, or 'blowing-house;' where formerly
the tinner might have his tin blown, paying the owner of the house 20s.
for every tide or twelve hours, for which the blower was obliged to deliver
to the tinner, at the ensuing coinage, one hundred gross weight of white
tin (metallic tin) for every three feet, or 180 lbs. of stream tin so blown, which
is equal to fourteen pounds of metal for twenty of mineral, clear of all
expense.
"Now that the blowing-houses are farmed, the tin is usually blown and
sold by sample, as the mine tin is at the reverberating furnaces. The
furnace itself for blowing the tin is called 'the castle,' on account of its
strength, being of massive stones cramped together, with iron, to ensure the
united force of fire and air. This fire is made with charcoal excited by two
large bellows, which are worked by a water wheel, the same as the iron
forges. They are about 8 feet long, and 2 wide at the broadest part.
The fireplace or castle is about 6 feet perpendicular, 2 feet wide in the top
part each way, and about 14 inches in the bottom, all made of moor-stone and
clay well cemented and cramped together. The pipe or nose of each bellows
is fixed 10 inches high from the bottom of the castle, in a large piece of
wrought iron called the Hearth eye. The tin and charcoal are laid in the
furnace, stratum super stratum, in such quantities as are thought proper, so
that from 8 to 12 cwt. of tin, by the consumption of twenty-four sixty-gallon
packs of charcoal, may be smelted in a tide, or twelve hours. Those
bellows are not only useful for igniting the charcoal, but they throw in a
steady and powerful air into the castle, which, at the same time that it
smelts the tin, forces it out also through a hole at the bottom, about
4 inches high and 1½ inch wide, into a moor-stone trough 6 feet high and
I foot wide, called the 'float,' whence it is laded into lesser troughs or
moulds, each of which contains about 3 cwt. of metal called slabs. 'Blocks,'
72
[BOOK I.
HISTORICAL SKETCH.
or 'Pieces of tin,' of a well-known form and size, are sold in every market
in Europe, and it is sold also in bars and bundles, which, on account of its
superior quality, is known by the name of 'grain tin.' This brought a price
formerly of 7s., and is further advanced the last two or three years to IOS.
or 12s. per hundred more than mine tin is sold for, because it is smelted
from a pure mineral by a charcoal fire; whereas mine tin is usually cor-
rupted with mundic and other minerals, and is smelted with a bituminous.
fire, which communicates a harsh sulphurous injurious quality to the metal"
(Pryce, 1778).
Borlase was so careful an observer, that it is important to collate his
description of mines and mining in his day. There are several streams of
tin in St. Stephen, Branel, St. Ewe, St. Blazy, and other places, but the
most considerable stream of tin in Cornwall is that of St. Austell Moor,
which is a narrow valley about a furlong wide (in some places somewhat
wider), running nearly three miles from the town of St. Austell southward
to the sea. On each side, and at the head above St. Austell, are many
hills, betwixt which there are little valleys which all discharge their waters,
and whatever else they receive from the higher grounds, into St. Austell
Moor, whence it happens that the ground of this moor is all adventitious for
about three fathoms deep, the "shodes" and streams from the hills on each
being here collected and ranged into floors, according to their weight and
the successive dates of their coming thither. The uppermost coat consists
of thin layers of earth, clay, and pebbly gravel, about 5 feet deep. The
next stratum is about 6 feet deep, more stony, the stones pebbly formed,
with a gravelly sand intermixed. These two coverings being removed, they
find great numbers of tin stones from the bigness of a goose egg, and
sometimes larger down to the size of the finest sand. The tin is inserted in
a stratum of loose smoothed stones, from a foot diameter downwards to the
smallest pebble. From the present surface of the ground down to the solid
rock or karn, is eighteen feet as a medium. In the solid rock there is no tin.
The stream tin is of the purest kind, and great part of it, without any other
management than being washed upon the spot, brings thirteen parts from
twenty at the melting-house.*
Streams of tin are thus described by Dr. Borlase: "These streams are
of different breadths, seldom less than a fathom, oftentimes scattered, though
in different quantities, over the whole width of the moor, bottom, or valley,
in which they are found; and when several such streams meet they often-
times make a very rich floor of tin, one stream proving as it were a magnet
to the metal of the other."
In the tenement of Douran, in the parish of St. Just (Penrith), in the
year 1738, there was a very singular stream of tin discovered. The ore was
pulverised, betwixt one foot and one foot and a half in depth or thickness,
of various breadth. In the moory ground, where it was first discovered, it
had a back of soil or gravel over it only two feet high; but, as the stream.
advanced farther east, it had still a higher covering, till at last it had all
Douran Hill (which may be about forty feet perpendicular) over it, the
* Upon delivering twenty pounds of this tinstone at the smelting-house, the smelter will contract to
deliver to the owner's order thirteen pounds of melted tin at the coinage.
CHAP. III.]
THE "BROIL" OF A TIN LODE.
73
stream still continuing its horizontal position. Dr. Borlase, led by the
prevailing opinion of his day, refers this to the action of the waters of the
deluge, but he does this very doubtfully, and asks: "But whether this
remarkable position of arenaceous tin is owing to the waters of the flood
(which indeed is a most fertile solution of subterraneous difficulties, but
I fear too often recurred to), may be well questioned." He then gives
an explanation of his own endeavours to free his mind of the trammels
of tradition, but it is very unsatisfactory, since it is purely hypothetical, and
unsupported by any natural evidences. However, he gives a very satis-
factory description of another remarkable tin stream, which was working
in his days (1758).
The "broil," or top of the lode, is particularly noticed by Dr. Borlase in
his "Natural History of Cornwall." "The lode has its top covered over
with a parcel of loose stones and earth, usually of the same impregnate,
though in a less degree, of the same colour and cement as the lode, and this
in Cornwall we call the 'broil' of the lode.
"This broil not being confined betwixt rocks, as the lode is, is frequently
found to have been disturbed, and sometimes wholly dissipated, especially
when the walls of the fissure reach up to-day, as they do in naked karns
(cairns), but where there is a layer of rubble, or stiff deep clay above the
fissure, which is much oftener the case, then the broil is always found
covering the lode and brooding as it were over the treasures beneath.
"The broil is found in greater quantity in the valleys than in the tops or
sides of hills; on the level ground it is but just moved from its first station,
and spread on each side of the vein in an equable manner; but, if the lode
has any declivity near it, then many of the loose stones of the broil are found
strewn down the hill. In Cornwall we call these dispersed parts of the broil
'shodes.'
(
Tonkin states, in a note to Carew's "Survey of Cornwall,” that as late as
1733 the shafts were very unimportant. "As for the damps, they often cure
them by sinking a new shaft, which they call an air shaft, and where that
cannot be conveniently done by bellows and pipes of lead or leather, a
method taken from Dr. Brown's Travels and Observations on the Mines in
Hungary,' p. 107. This was put in practice the first time by my father, to
carry on St. George Adit in Goonlaze, St. Agnes, where by reason of the great
depth (at least forty fathoms from the grass) it was impossible to sink a shaft;
and so to have succeeded without this invention; since which it has been
tried in other places with like good success. But note that this was
invented by the Lord St. Albans, and practised in Wales by his servant
Thomas Bushell, Esqr." +
Lord De Dunstanville adds a note to this. "From the search which has
been made during so many centuries for stream tin in Cornwall and Devon,
it is difficult to obtain sections of unmoved ground at present, except in situa-
tions where the tin-stone pebbles are not very abundant. Hence we can form.
a very inadequate idea of the great accumulations which must have been
first worked, and consequently of the tin-stone pebbles swept into the bottom
* Perhaps from the Teutonic word Shutten, to pour forth.
+ Fuller's "Worthies in Wales," p. 4.
74
[BOOK I.
HISTORICAL SKETCH.
of valleys, or into basin-shaped depressions (such as occur at the Tregoss
Moors, and on the north of Wendron), by the body of water which appears
to have passed over this land. Traces of stream works are to be seen from
Dartmoor to the Land's End, often in depressions on the higher grounds,
as, for example, on the former elevated region, whence tin pebbles have long
ceased to be obtained, being the works of the old men, as the ancient miners
are universally termed in Devon and Cornwall.
"Though the richest deposits seem to have been well worked, and the
ground turned over twice or thrice, the tin-stones rejected at one time
becoming valuable from their comparative scarcity at another, there is still
enough of unmoved ground here and there working to enable us to judge of
the accuracy of the general geological facts stated to be observable in con-
nection with the tin-grounds. This is more particularly the case where
modern enterprise has directed works beneath the level of the sea, as at
Pentuan: or, abstracted the tin-stone pebbles from beneath the silt and sands
of an estuary, permitting the latter gradually to fill up the space once occu-
pied by the tin-ground, as is now done in Restronget Creek, near Falmouth,
which will be referred to in the section devoted to detrital tin deposits, when
a section of the Happy-Union stream work at Pentuan, as observed in 1829
by Mr. Colenso, will be especially noticed.
"From information collected respecting the cutting of the Par Canal,
and from mining operations, it would appear that the tin ground in the
neighbouring valley of Par was covered by marine deposits to a level that
would correspond with that observed in the St. Austell Valley; and it is
worthy of note that when the cutting of Par Canal was effected at Pons Mill,
near St. Blazey, granite blocks were found arranged for a stone bridge nearly
20 feet beneath the gravel, which had accumulated upon it in no small quan-
tity, probably from the washings of the tin stream works higher up the valley,
sections of which have been published by Mr. William Jory Henwood.* The
following is a section obtained by Mr. M'Lauchlan from Captain Barrett, of
East Crinnis mine. One seen in a shaft sunk in a part of the lower ground
near the Par estuary:
1. River deposit
2. Confused mass of mud, sand, clay, and stones, which has been disturbed by
the "stream tinners "
3. Mud, clay, and vegetable matter, apparently an old surface
Feet. Inches.
I 6
78
4. Fine sand, containing sea-shells, like cockles, and on the top rolled pebbles. 4
5. Mud, clay, sand, wood, nuts, and other vegetable productions mixed
6. Tin ground, resting upon an uneven surface of slabs
3
6 inches to 6 feet †
In the Carnon valley, on the north of Falmouth, and up the continuation
of that valley inland, in the direction of the Gwennap mines, we have another
example of tin ground partly beneath marine accumulations, and partly
covered by common river detritus.
The following is a section of another of the Carnon stream works, by
Mr. W. J. Henwood, than whom no man had a more perfect acquaintance
with the diverse operations of mining and streaming in Cornwall:—
* “Transactions of the Geological Society of Cornwall," vol. iv. pp. 60-64.
† Sir Henry de la Beche's "Report on the Geology of Devon and Cornwall."
CHAP. III.]
SECTIONS OF TIN DEPOSITS.
1. Sand and mud (River wash)
2. Silt and shells (Three successive beds)
3. Sand and shells (A stream of fresh water percolates this bed)
4. Silt (Three beds)
5. Sand and shells
•
6. Silt, mixed with shells in large quantities
7. Silt, in some places containing stones
8. Wood, moss, leaves, nuts, &c., all of a dark colour, resembling what has been
charred; a few oyster-shells, animal remains, those of the deer being most
abundant, and some human skulls
•
Towards the sea the bed 8 entirely disappears, giving place to 7, which
reposes on
9. The tin ground, which consists of rounded masses of tin ore, in some cases
unmixed with any other substances; in others, in a matrix of quartz and
schorl, with rounded pieces of slate, granite, and quartz, varying in thick-
ness from a few inches to
Feet. Inches.
75
•
3
O
•
ΙΟ
2
0
12
1 6
0*
The shelf, or surface of rock, upon which the whole reposes, is composed
of the ordinary Clay-Slate (killas) of Cornwall.
The higher stream works at Carnon have been for some years abandoned,
the search for stream tin being confined to the bottom of Restronget Creek.
At this point works have recently been carried on by Messrs. Taylor, by
sinking a cylinder through the tidal waters of the estuary, and working
underneath the creek upon the tin ground.
Sir Henry de la Beche says, after remarking that the stream tin found
in the north of Cornwall, as well as on the south, was covered by marine
deposits to a certain height up the valley, continues, "Here also (Carnon
Stream) on the south, a bed in which vegetable remains are abundant, chiefly
oak trees (?), the roots of which were described to us as standing in the
position in which they appear to have grown, rests on the tin ground towards
the seaward termination of the valley." +
Mr. Edward Smith gave, in 1837, the following section of Carnon Stream.
This name has been given to a long line of works, so that the minor details
may be expected to vary during the distance :-
1. Mud and gravel
2. Granite gravel, intermingled with small pieces resembling charcoal, and a
few shells
3. Fine gravel, mud, and shells
About this depth are several irregular strata of oysters, about 4 or 5 feet
in thickness, extending irregularly, and within 4 or 5 feet of the tin
ground.
4. Closer mud, intermingled with shells.
In this stratum have been found several branches and trunks of trees, some
of which had evident marks of having been cut with an axe or other
sharp instrument; horns and bones of stags, likewise human skulls.
5. Tin ground, varying from
•
7 feet.
•
4
12
19 "
I foot to 6,,
Shodes, as defined by Dr. Borlase, requires attention: "Tin is also
disseminated on the sides of hills in single stones, sometimes a furlong or
more distant from these lodes, and sometimes these loose stones are found
together in great numbers, making one continued course from 1 to 10 feet.
deep, which we call a stream, and when there is a good quantity of it the
tinners call it, in the Cornish tongue, Beuheyle, or a Living Stream; that is, a
course of stones impregnated with tin. In like manner, when the stone has
a small appearance of tin, they say it is just alive; when no metal, it is said
to be dead, and the rubble which contains no metal is called deads."
* “Transactions of the Geological Society of Cornwall," vol. iv. p. 58.
+ "Geological Survey of Cornwall and Devon," 1839.
76
[BOOK I.
HISTORICAL SKETCH.
•
In the reign of Queen Anne the tin mines of Cornwall were in a most
depressed condition, and several attempts were made to induce the Govern-
ment to give some assistance to the tin miners. This led eventually to a
Convocation, or "A Parliament of Tinners," from which the miners of Corn-
wall were led to expect great benefits. The following condensed statement
of this extraordinary meeting will therefore form an interesting supplement
to the Historical Sketch of the History of our Earliest Mining Operations.
A Journal of the Convocation of four and twenty Stannators, or Parlia-
ment of Tinners for the Stannaries of Cornwall, held at Truro the 20th day
of February, in the eighth year of the reign of our Sovereign Lady Queen
Anne, before the Hon. Hugh Boscawen, Esq., Lord Warden of the Stan-
naries of Cornwall and Devon, &c. &c., and by several prerogatives con-
tinued and put over unto the 20th day of April, in the ninth year of Her
Majesty's reign, A.D. 1710.
The Lord Treasurer Godolphin sent down his nephew, the Lord Warden,
with a commission from the Queen to call a Convocation, and with articles
and instructions for the said new farm. Mr. Tonkin represents that the
"generality of the people, who seldom trouble their heads with what may
come after, were very fond of 'the new farm.' But it was not so with most
of the gentlemen and principal owners of tin mines." They are said to have
been "very indifferent as to a farm, as being truly sensible of those mis-
chiefs that might attend it, and were therefore for taking their chance; or if
there must be a farm, were resolved not to accept of it but on the same
terms with the former, and a redress of the great grievances occasioned by
the surplus tin beyond what was contracted for."
The Convocators returned," as they were known to be, in the true interest
of their country," were divided into two parties—the one of fourteen, distin-
guished by the title of Anti-Wardenists, or the country party; the other
called Wardenists, or the court party.
In these debates it was soon discovered that the neutral gentlemen had
acceded to the Wardenists, and therefore the Anti-Wardenists resolved to
avoid the consideration of the Lord Warden's speech, &c., till those two
members were returned. To which an unforeseen accident gave them a fair
handle likewise, for this very evening some hot-headed fellows, pretending
a great deal for the country's welfare, and finding that the majority of the
Convocation, &c. &c., were against a farm on the terms proposed, sent to
all the tinners in the neighbourhood to force the Convocation to a farm.
Die Sabbati, vicesimo secundo die Apriles. By sun-rising this morning the
tinners, and all the mob round the country, to the number of at least 5,000
or 6,000, were come to town according to their summons, and behaved them-
selves in a very disorderly manner. The result, however, of this tumultuous
gathering was that the Lord Warden came forthwith to the Convocation,
and having ordered the door of the Coinage Hall to be thrown open, which
was immediately filled with a crowd of people, he rose up and made a short
speech to this purpose-that the Convocators had the real interest of their
country truly at heart, and that they would, he had no doubt, pursue the
best methods to obtain it, and that, for his part, they would not show
their regard to him in a better manner than by departing immediately to
CHAP. III.]
THE PARLIAMENT OF TINNERS.
77
their respective homes. Upon which the crowd gave a loud huzza, and
gradually dispersed.
After several days of very angry and often wordy discussion, it was
resolved, “That this Convocation is willing to contract with Her Majesty
for the tin of Cornwall for seven years, from the first day of June next,
according to the articles of instruction annexed to the Lord Warden's
commission for holding this Convocation."
It was ordered that the title of the deed drawn up should be—” That the
title thereof be An Act of Convocation, or Parliament of Tinners, for a
contract with the Hon. Lord Warden, on behalf of Her Majesty, for the
tin of Cornwall for seven years, to commence the first day of June, 1710.'
The Convocation attended by arrangement in the Coinage Hall, to meet the
Lord Warden, and gave assent and confirmation to the Act for a contract
with Her Majesty for the tin of Cornwall.
Mr. Tonkin quaintly says, “Thus under this Convocation, which met
with great expectations, of what they would do for keeping up the price of
tin, and restoring and confirming the laws, customs, and constitutions of the
Stannaries, but performed nothing at all.”*
Many of the mines of Cornwall have been worked under conditions of
exceeding difficulty; but no case of mining enterprise shows so completely
the perseverance of the Cornish miner, and his disregard of difficulties, as
that of his sinking a shaft in the middle of the sea, and working for some
time a tin mine of much promise, called The Wherry, near Penzance,
midway between Newlyn and Penzance.
This most singular mining work was executed more than a century ago,
near the shore. At low water, in a place where a gravelly bottom was left
bare, there was discovered a multitude of small veins of tin ore, which
crossed each other in every direction and ran through the Elvan rocks. This
ridge of rock jutting into the Mount's Bay also contained this mineral in
considerable quantities. On several occasions tin miners had worked upon
these small veins at low water, especially at spring tides; but the black tin
thus discovered rarely paid for the time and labour expended.
* The Prices of Tin per cwt., from 1783 to the end of the century, is from the Report of the Select
Committee of the House of Lords on the State of the British Wool Trade :- *
£ s. d.
1783
1784
4
I 7 per cwt.
1792
4 I
1785
4 3 0
1786
•
4 3
1787
4 3
1788
4
I
1789
3 10
1790
3 15
NON 2 736
2
1793
1794
2
""
1795
•
""
1796
""
1797
""
1798
""
1799
1791
•
•
4 0 3
""
·
£ s. d.
4 18
о
o per cwt.
об ""
""
4 18
""
5555
о
""
6
""
5 0
5
The following quantities of Tin were supplied by the Miners of Cornwall, under the Stocking System, to
From October, 1793
the East India Company :-
to
April, 1794
December, 1794,
January, 1796
May, 1795
December, 1796,,
""
""
November, 1797,
December, 1798
""
November, 1799,,
June, 1796
April, 1797
March, 1798
May, 1799
April, 1800
•
•
•
tons cwts. qrs. lbs.
1232 16 2 17
1202 5 O 26
I 202
1062
4 I 14
4 O 9
1229 16 I 15
802 17 I 24
687 10 3 7
* The annual produce of the Tin Mines of Cornwall, from 1750 to the present time, will be found in
the Appendix.
78
[BOOK I.
HISTORICAL SKETCH.
The first attempts to work this singular mine are said to have been
made towards the beginning of the last century, when the small veins of
tin were first observed to cross the rocky shoal which is exposed to view at
low water. How long this first party of miners persevered in their difficult
enterprise, and what were the mechanical aids of which they availed them-
selves, is not known; but the works, after being sunk to the depth of a very
few fathoms in the rock, were abandoned.
About the year 1778 a poor miner in the parish of Breage, whose name
was Thomas Curtis, had the boldness to renew the attempt. The distance of
the shoal from the neighbouring beach at high water is about 120 fathoms;
and this, in consequence of the shallowness of the beach, is not materially
lessened at low water. It is calculated that the surface of the rock is covered
about ten months in the year, and that the depth of water on it at spring
tides is 19 feet. The prevailing winds occasion a very great surf here even
in summer, but in winter the sea bursts over the rock in such a manner as
to render all attempts to carry on mining operations unavailing.
Such were the difficulties which a poor individual had to surmount
whose whole capital, perhaps, was not £10. As the work could be prose-
cuted only during the short period of time when the rock appeared above
water (a period which was still further abridged by the necessity of previously
emptying the excavation), three summers were consumed in sinking the
pump shaft, a work of mere bodily labour. The use of machinery then
became practicable, and a frame of boards being applied to the mouth of the
shaft, it was cemented to the rock by pitch and oakum, made water-tight in
the same way, and carried up to a sufficient height above the highest spring
tide. To support this boarded turret-which was 20 feet high above the rock
and 2 feet 1 inch square-against the violence of the surge, eight stout bars
of iron were applied in an inclined direction to its sides, four of them below
and four of an extraordinary length and thickness above. A platform of
boards was then lashed round the top of the turret, supported by four poles,
which were firmly connected with these rods. Lastly, upon this platform
was fixed a winze for four men.
It was thought that the miners would thus be enabled to pursue their
operations at all times, even during the winter months, whenever the weather
was not particularly unfavourable; but as soon as the excavation was carried
to some extent in a lateral direction, this was found to be impossible; for
the sea water penetrated through the fissures of the rock, and in proportion
as the workings became enlarged, the labour of raising the waste to the
mouth of the shaft increased. Curtis's predecessors, as well as himself, had
carried on their excavations too near the surface, which not only made the
rock more permeable, but less able to resist the immense pressure of water
at high tide, so that it became necessary to support it with large timbers.
To add to this disappointment it was found impossible to prevent the water
from forcing its way through the shaft during the winter months, or, on
account of the swell and surf, to remove the tin-stone from the rock to the
beach opposite.
The whole winter, therefore, was a period of inaction; it was not before
April that the regular working of the mine could be resumed. Neverthe-
CHAP. III.]
WORKINGS OF THE WHERRY MINE.
79
less, the short interval which was still allowed for labour below ground,
sufficed most richly to reward the bold and persevering projector, and to
give his mine the reputation of a very profitable adventure.
Whether he ever felt a conviction of the possibility of removing so many
natural obstacles to his complete success is not known, although there is reason
to suppose that he did; for when Mr. Hawkins asks Curtis's "opinion of the
scheme of erecting a lighthouse on the tremendous Wolf Rock, he professed
his belief in its practicability, but suggested, as far preferable, the blowing up
of the entire rock, which he readily engaged to do for a proper remuneration."
The following was the state of The Wherry in the autumn of 1791, as
described by Mr. Hawkins in the Geological Society's Transactions:-
'Depth of the pump, shaft, and workings, four fathoms two feet. Breadth
of the workings, eighteen feet. The roof was worked away in some places to
the thickness of three feet. Twelve men were employed for two hours at the
wing in hauling the water, while six men were teaming from the bottoms into
the pump. The men worked on the rock for six hours afterwards; in all,
eight hours. Thirty sacks of tin-stone were broken on an average every
tide; and ten men in the space of six months, working about one-tenth of
that time, broke about £600 worth.
<<
"The workings were confined to a course or channel of Elvan, a porphyritic
rock, about eighteen feet in breadth, which runs N.W. and S.E., and under-
lies one foot and a half in a fathom to the S.W. It is discoverable on the
beach at half-tide. Besides the small veins of tin which ran through this
rock, its whole mass was impregnated with tin to such a degree as to be
worth the expense of raising; fifteen feet of the eighteen which composed
the breadth of the Elvan producing 1,000 cwt. of 'white tin' in 1,600 sacks,
and another foot as much as I cwt. of white tin in every sack.
“On a close inspection of the mass in which the tin was thus abundantly
dispersed, the grains appear of a crystalline transparency, and so equal in size
and regularly distributed as to form, as it were, one of the constituted parts
of the porphyry: the term stannified granite was applied to it. It is said
to have been the first tin-stone that was ever burnt in Cornwall before it was
sent to the stamping-mill: a common lime-kiln having been erected for that
purpose. The object of this operation was to render the texture of the
stone more friable.”
In September, 1792, Mr. D. Gilbert wrote to Mr. J. Hawkins as follows:
"The course of stanniferous porphyry near Penzance (the Wherry) promises
to make a very great mine. There are indications of the tin being con-
tinued to a great extent in both directions, and the bottoms are growing
longer and remain rich. A house near the green, built with fragments
of this stone, which were probably picked up on the shore, or broken
from the top of the rock, is, I hear, to be pulled down and rebuilt with
other stone, for the sake of its tin. An adventurer told me that £3,000
worth of tin has been raised from this extraordinary mine in the course of
the present summer."
In a subsequent letter Mr. Gilbert says: "A steam-engine is erecting on
'the Green' opposite, and they are constructing a wooden bridge from thence
to the rock, to serve as a communication, till the engine-shaft has been sunk
80
[BOOK I.
HISTORICAL SKETCH.
sufficiently deep, and a drift worked out to the mine, as a stage for supporting
the sliding, or rather hanging rods."
The bridge thus constructed answered also the purpose of conveying the
ore and deads to the shore. In this manner the mine was conducted, and ore
to the amount of £70,000 was raised from it. Nor, indeed, were its treasures
exhausted at its close, which was as romantic as its commencement. An
American vessel broke from its anchorage in Gwavus Lake, and, striking
against the stage, demolished the machinery, and thus put an end to an
adventure which, both in ingenuity and success, was probably never equalled
in any country.*
This mine was again worked a few years since; but although there
was a large sum of money expended, and all the advantages of the appli-
cation of improved machinery secured, it failed to be profitable, and was
eventually abandoned. It should be remarked that, in addition to tin, some
minerals of a rarer character were produced at the Wherry: amongst others,
were valuable ores of Cobalt, and at one period an attempt was made to
manufacture Smalts from this ore. This interesting process does not
appear to have continued long, and the fact of the manufacture lives only
as a tradition. Even within the last few years, good specimens of tin-
white cobalt have been collected from the crevices of the rocks, a short
distance above low-water level, between Penzance and Newlyn.
The Wherry mine was not the only mine in Cornwall which was worked
under the sea. At Trewavas mine, not far from Helstone, the engine-houses
were built on the edge of the most romantic cliffs, and the levels driven
out under the waters of the beautiful Mount's Bay, and worked so closely up
to the sea bottom, that a large quantity of water penetrated through the
rock, and that accumulated in the mine was exceedingly salt. A similar
exploration under the sea was made at Wheal Providence, near St. Ives. In
this mine there were two levels driven at depths below high-water mark of
24 fathoms and 32 fathoms respectively, both of which were wrought 20 fathoms
out under the sea. Here the water was not salt, and the miners could
scarcely hear the noise of the waves.
•
A still more remarkable example of mine workings under the sea has
been in existence since the days of Pryce (1778). "At Wheal Cock," he
says, “they have only a crust between them at most, and though in one
place they have barely four feet of stratum to preserve them from the raging
sea, yet they have rarely more than a dribble of salt water, which they
occasionally stop out with oakum and clay, inserted into the crannies through
which it issues." This mine forms a part of Botallack, which has been
worked at a depth of 1,500 feet below the sea-level, and 2,248 feet under the
Atlantic Ocean. Mr. W. J. Henwood relates that, when standing in that part
of the mine where but 9 feet of rock stood between him and the ocean, the
heavy roll of the large boulders, the ceaseless grinding of the pebbles, the
fierce thundering of the billows, with the crackling and boiling as they
rebounded, placed a tempest in its most appalling form too vividly before
him to be ever forgotten.
"A Treatise on the Progressive Improvements and Present State of the Manufactures in Metal,”
vol. iii. Revised by Robert Hunt. 1853.
"Mineralogia Cornubiensis.”
CHAP. III.]
THOUGHTS ON THE TIN TRADE.
81
About the end of the last century the tin trade was in a most depressed
state, and the following letter, written in 1780 by one of the most active
of the tin smelters, is deserving attention:-
Some thoughts on the present mode of carrying on the Tin Trade, so far as it relates to the sending Tin
to London and Bristol for sale; with a sketch of a plan for putting that trade on an eligible footing.
An Address to the Gentlemen Tinners of the County of Cornwall.
GENTLEMEN,-The tin trade of the county of Cornwall is an object of such magnitude and importance
that every Cornishman is actually, or virtually, interested in its success; therefore, every attempt to promote
it is at least laudable, which it is hoped will be a sufficient apology for this address.
It is really difficult to account for the strange infatuation that has so long prevailed, relative to the
mode of carrying on the tin trade, especially that part of it which is the subject now under consideration.
The people of this county are by no means deficient in understanding, spirit, and activity on most occasions,
yet they suffer themselves to be dictated to by their agents in London, and permit them to decide, and fix
a value on the tin consigned to them, just as it suits their own interest, without consulting the interest of
their employer, though the means of redress are always in their own hands.
The tin trade has long been in a languishing state, and will soon be in a much worse, unless speedy
and effectual remedies are pointed out and applied. For the sake of the honour and reputation of the
county, and still more for the sake of the poor industrious tinner, whose distress, great as it now is, must
otherwise be greatly increased, it is necessary that proper measures be instantly adopted to prevent
the impending evil.
I shall therefore proceed to show that the remedy is not only certain, but in your own power. Among
the different causes of the present disagreeable state of this great staple commodity, the first and great
cause seems to be the lodging the tin sent to London and Bristol for sale in the hands of improper persons.
The story of the farmer setting the fox to watch his geese is very applicable to my countrymen em-
ploying for their agent in the sale of tin, the pewterer, whose interest it is to keep down the price as low
as he can--the lower it is, the more is his profit in manufacturing.
This is the root of the evil, and it is a matter of astonishment how a practice so inconsistent and
absurd was ever introduced, but still more so that it should be persisted in, though the fatal effects of it
are as evident as the sun at noonday, and are universally complained of, even by the persons who still
continue to pursue this mode in spite of the voice of reason, interest, and common sense.
In truth, a certain great little man seems to have acquired the art of fascination, and to have attained such
an ascendant over the minds of those who employ him to sell their tin, that neither the allurements of
interest, nor the resentments which have frequently arose from his improper behaviour, are sufficient to
break the charm, but he goes on to decide on the price of tin just as it suits his interest or caprice.
If no other persons suffered by this but those who employ such agents, the mischief would not be
properly a subject of public discussion; but in fact, not only the whole body of tinners, but every man who
has a landed estate in the county of Cornwall, is materially interested in the effect of this conduct, as the
price of tin is now under the power and control of the pewterers, who raise fortunes at their expense.
To enumerate every particular that could be brought forward to elucidate this matter, is equally
tedious and unnecessary: the fact is notorious, and the persons who have hitherto submitted to this
disgraceful treatment are ready on every occasion to acknowledge it, and seem only to wish to know how
they may get out of the toils in which they are involved.
The second cause of the present situation of this valuable trade arises from the dividing the tin sent
for sale into too many hands.
One great mischief arising from this practice, is the giving the buyers an opportunity of going round
to the different agents and spreading reports that such a person offers to make an allowance of one kind,
and another of a different nature, and thereby creating jealousies amongst those who wish to sell
the commodity with which they are entrusted at a reasonable price, and render a good account of sales to
their employers. This being done, the consequence is, poor Cornwall is the sacrifice; down goes
the price of tin, without even a shadow of reason for it: this I have known to happen repeatedly, and even
the factors themselves (pewterers excepted) have lamented it, and owned there was no just reason
for lowering the price of the commodity, and that not a block more would be sold on account of their
reduced price.
To illustrate this by a recent fact. Last year a new duty of twopence per hundredweight was laid on
tin exported, which was of course charged to the exporter, as all other duties were: but in London the
dealers in tin first spread insinuations amongst the different agents that they could buy it without paying
the new duty, and have at last insisted that it shall be borne by the tinner, and not by the exporter. A
fact this, which speaks loudly the necessity of adopting some plan to remedy this and other evils of
the same nature.
Other causes might be enumerated, but as the remedying those already mentioned will cure most of
the subordinate evils, I shall only mention one more, which is the want of union amongst ourselves, in not
fixing a general and reasonable price on the tin we send to London, and confining our agents strictly
to the observance of our orders, and on no pretence permitting them to sell under the price agreed on.
This is so evidently a mischief, that it would be an insult to your understandings to attempt a formal
proof of its being so. The only thing to enquire at present is whether any proper union subsists amongst
the different persons who send tin to London and Bristol for sale. For the solution of this question
I appeal to all persons interested in this trade who know and feel the fatal consequences of the want
of union, and who will, I doubt not, be ready to adopt any durable and effectual plan which may be
proposed to redress the present alarming condition of this once flourishing trade.
If the causes here assigned are founded in fact-and that they are so is too evident to need any
further proof-the remedies for our distress are self-evident. The following short sketch of an association
G
82
[BOOK I.
HISTORICAL SKETCH.
for that purpose is submitted to your consideration; and, as I am informed, the Vice-Warden of
the Stannaries has been requested to call a meeting* of the principal tinners, which he has promised to do
as soon as he possibly can attend it. You will consider it in the meantime, and come prepared to make
such additions and alterations as you may think most likely to promote the general good.
First, let us engage, and pledge ourselves to each other, that we will, on no pretence whatever, send
or consign a block of tin for sale, to any pewterer, either in London or Bristol.
Secondly, Let us enter into an association, and have only four agents in London and two in Bristol;
to one or other of whom we will consign all the tin we send for sale, and to no other person whatever.
Let all tin so consigned be sold by each agent, rateably in proportion to the quantity he receives, without
any preference; and let it be a positive order that the cargo that arrives first shall be sold first. Let
the price at London and Bristol be governed invariably by the price in Cornwall, viz.: seven shillings per
hundred above it, for all tin sold for home consumption; and upon what is exported let all additional duty
and expense be borne by the exporter. Let our agents have a commission of one shilling per hundred;
and let all tin be paid for on delivery, by an accepted bill, payable three months after date. Let
our agents give such security, for the trust reposed in them, as may be thought adequate to it; and let it
be resolved, that if either of the agents hath sold all the tin consigned to him, previous to the arrival of a
fresh supply, he shall have a right to call on either of the others who have tin on hand, to supply his
particular customers; and in that case, the commission shall be equally divided.
This, Gentlemen, is the outline of a plan, submitted to your consideration, by one who heartily wishes
to promote the honor, interest, and happiness of his native country. The evils, proposed to be redressed,
grow daily more and more unsupportable; the mode here recommended for redressing them seems
obvious, easy, and in your own power. Exert yourselves, gentlemen, like Cornish men, and one and all
unite to promote your own and your country's good, and no longer suffer your Agents to dictate to you as if
they were your Masters; nor permit an insignificant pewterer to raise a princely fortune out of the
distresses of the poor industrious tinner.
I am, Gentlemen,
Your faithful and obedient Servant,
CORNUBIENSIS.
* Since the above was printed, I see the Meeting is advertised to be held at Helston, on Friday, the
28th of January, 1780, which it is hoped every person interested will not fail of attending.
In the Appendix to this volume-in which it is intended to collect and
tabulate all available statistical information on the trade in the metallic
produce of these islands—will be found a general statement of the tin trade
of Cornwall, and of the tin produced in other countries.
It is thought that by a well-digested arrangement it will be possible to
construct a series of tables which shall be easy of reference, and at once
show to the inquirer, the exact state of our mineral industries, at any period
since records have been preserved. At the same time the text will be free
from the encumbrances which usually offend the eye in the shape of tabular
matter.
CHAPTER IV.
MINING FOR TIN AND COPPER TO A.D. 1800.
TIN.—Mining for tin and copper was carried on, in 1770, without any system
of bounding. Permission was, at that time, obtained from the lord of the soil,
and an acknowledgment-" dish," or "dues," was paid to him for permis-
sion to search. This was commonly one-sixth, one-seventh, one-eighth, or
even to one-twelfth, or less. The dues for copper were payable in money,
and those for tin in the stone or mineral, or in the metal called "white tin.”
This grant by lease ran for one-and-twenty years certain. Pryce says,
in 1778: "I do not suppose the present methods for working mines by deep
shafts, and by 'driving' and 'stopeing,' under the firm ground has been
practised more than three hundred years." This of course carries us back to
the fifteenth century, and I am disposed to believe that we have indications
of actual mining, by sinking shafts, and piercing the ground, by adits, or by
levels, from a much earlier period.
Agricola, publishing his remarkable work in 1546, gives a considerable
number of plates, which prove that mining had advanced beyond the mere
digging of pits in his time. Numerous forms of machinery and tools, with
implements, are given, all of which show that much thought had been
devoted to the means necessary for the extracting, and also for the preparing,
of the minerals raised, for the market. All this must have required the
experience due to the influence of a long period of time.
About 1570 or 1580, Queen Elizabeth, as we have already stated, intro-
duced a number of German miners into this country for the purpose of
improving the British miners. Of course those men brought with them all
the appliances which had been for a long period familiar to the miners of
Saxony and Germany. Notwithstanding this, we find, in 1778, that no con-
siderable advance has been made by the Cornish miners. With true Celtic
obstinacy, they had remained satisfied with the methods used by their
forefathers. We cannot do better than quote from Pryce his description of
the mining operations with which he must have been familiar.
(c
Bal-spelt by Carew, Ball-is always in the singular number, with
some adjunct to it, as Godolphin Bal, Ballanoon, Trevaunance Bal, &c.,
and signifies a parcel of tin mines—or working together—and has not the
name from a valley-for many of them are very high. . . . Some, therefore,
derive this word from the old British Bala or Bal, which, says Mr. Llhwyd
(in his addition to Camden, in Merionethshire), signifies a village, or in old
Irish, a place, as who would say, 'a place of tin;' others chose to derive
it from bali-pali, to dig, bal or pall. This indeed seems to be the most
natural derivation."
G 2
84
[BOOK I.
HISTORICAL SKETCH.
Lord De Dunstanville adds: "If we consider the different ways of
expressing themselves, this will appear to be right. When you ask a tinner
in the morning where he is going, he will answer you, 'Going to moore,' if
to a stream work; but if to work in a mine, he varies his phrase, and tells
you he is 'going to bal,' to let you know he is going to dig."
"Prior to these means for mining tin—that is, by shafts and underground
levels," Pryce says, "they wrought a vein upon the 'bryle' (¿.e. upon a dis-
turbed piece of ground, supposed to be the outcrop of the mineral vein,—a
disordered mass. I believe it was originally intended to express an idea
that the lode had 'boiled' over at this place) to the depth of eight or
ten fathoms all open to grass (that is the surface), very much like the
'fosse' of an intrenchment. This was performed by mere dint of labour,
when men worked for one-third of the wages they now have. By that
method they had no use for foreign timber, neither were they acquainted
with the use of hemp or gunpowder. This fosse they call a 'coffin
(some good examples of these 'coffins' are still to be traced in many
mines, as in Providence mines, St. Ives-in Polberro, St. Agnes, in the
mines in Baldhu-and at Drake Wales, near Calstock), which they laid open
several fathoms in length, east and west, and raised the tin stuff on 'sham-
mels'—plots or stages six feet high from each other till it came to grass.
Those shammels, in my apprehension, might have been of three kinds, yet
all answering the same end. First they sunk a pit one fathom in depth
and two or three fathoms in length, to the east and to the west of the middle
of the lode discovered; then they squared out another such piece of the lode
for one or two fathoms in length as before; at the same time others were still
sinking the first or deepest ground sunk, in like manner. They next went on
and opened another piece of ground each way from the top, as before, while
others were still sinking in the last, and in the deepest part likewise; in this
manner they proceeded step after step, from which motion arises the modern
method of stopeing' the bottoms underground. Thus they continued
sinking fromcast' to 'cast,'-that is, as high as a man can throw up the
tin stuff with a shovel-till they found the lode become either too deep for
hand work, too small in size, very poor in quality, or too far inclined from its
underlie for their perpendicular workings. Secondly, if the lode was bunchy,
or richer in one part than another, they only laid open and sunk upon it,
perhaps in small pitches not more in length than one of the 'stopes' or
'shammels' before described. The shortness of such a piece of lode would
not admit of them sinking stope after stope; it was then natural and easy
for them to square out a shammel on one side or wall of the lode, and so
make a landing-place for their tin stuff, cast after cast. Thirdly, if the lode
was wide, and the walls of it and the adjoining country very hard, solid
ground, it was in such case more easy for them to make shammels or stages,
with such timber, &c., as was cheapest and nearest at hand."
<
The following, also from Pryce, sets forth in the simplest and clearest
manner the method of working a mine in the eighteenth century :—
"We shall now set forth the first arrangements for working a mine, in
order to which, the principal thing to be thought of is a shaft to cut the lode
at twenty or thirty fathoms deep, if it is possible to be done. Here it is
CHAP. IV.]
MINING IN THE EIGHTEENTH CENTURY.
85
necessary to form some judgment of the inclination or underlie of the lode,
before we attempt to sink a shaft; for instance, if the lode underlies to the
north about three feet in a fathom, and a shaft is designed to come down
upon the lode in twenty fathoms sinking, the miner must go off north from
the back of the lode full ten fathoms, and there pitch his shaft, by which
means he is certain to cut the lode in the shaft about twenty fathoms deep;
because for every fathom the lode descends in a perpendicular line, it is also
gone three feet to the north of the perpendicular.
"A proper working shaft, upon which a whym may be erected if neces-
sary, should be six feet long and four feet wide, or more where large water
barrels are wanted; and the harder the ground is, the longer and wider the
shaft ought to be, that the men may have the more liberty to work and break
it, the area of a large shaft being more easy to rip up where the ground is
hardest than of a small one where it is more confined together and breaks
in shreds of stone, &c.
“A shaft that is designed for a water-engine may serve, if it is of
the size of the largest working shaft, but a fire-engine shaft ought to be
at least nine feet square, or ten feet by eight, or, in fact, to contain three
shafts in one, which must be partitioned into three compartments, all the
way down from grass to the deepest bottom of the mine. One-half is divided
for the pumps and engine-work; three feet in length of the other is propor-
tioned for a foot-way, to go down and rectify the pumps when amiss; and
the remainder is divided also by a partition of boards for a whym-shaft to
draw the deads and ore from the sump of the mine. If the ground is hard
and very wet, or the water very quick upon the men in sinking, there ought
to be eight men employed to sink a working shaft; that is, two men in a
corps of every six hours, and in a fire-engine shaft there should be sixteen
employed in the same manner; but if the ground is tender, and there is no
hindrance by water, six men in the first, divided into three corps every eight
hours, are reckoned sufficient; yet I have known four-and-twenty men put
to sink an engine-shaft upon emergency.
"The working shaft being sunk downright until it cuts the lode, they
open the vein, or sink the body of the shaft through it; and if they think the
vein is worth following, they sink the same shaft deeper in the body of the
lode, upon its inclination or underlie; whence the shaft becomes, and bears.
the name of an underlier. At the same time they turn house,' as they
call it, from the bottom of their perpendicular, or from the top or beginning
of the underlie. So that when the lode is well impregnated, they turn house
by driving or working horizontally on the course of the vein either to the
east or to the west, or both, as they find it most likely to answer their expec-
tations, in order to make a fuller trial and discovery. Where the lode
answers well in thus driving upon it, they continue to do so till they are
prevented by want of air, or till the end of their workings is too far from the
shaft, and the expense of rolling back the stuff to the shaft is great and
incommodious; then it is proper to put down another shaft as before des-
cribed, or more to the north, because it will be more convenient the longer
it continues downright. Meanwhile, they are mindful to sink their first shaft.
in order that they may work away the lode from thence in stopes, and have
86
[BOOK I.
HISTORICAL SKETCH.
a little sump or pit in that place as a basin for receiving the water of the
lode, whence they discharge it to grass by the easiest method they can
devise; for most lodes have streams of water running through them; and
when they are found dry, it seems to be owing to the waters having been
forced to change their course, either because the lode has stopped up the old
passage, or because some new or more easy ones are made, whereby the lode
and strata adjacent to it are bleeded, as we term it. However, they are
often hindered from going down deep enough to find any great quantity of
ore by the burden of water that most veins abound with; therefore, if the
mine is not encouraging, they give over any further pursuit; but if it seems
likely to prove well, and the lode lies in an ascending ground, they quit the
vein for the present, and go down to the most convenient place in the valley,
and from thence they bring a French-drain or conduit-which they call an
adit-tye or level-and so they work and drive this passage through the hill
in a right-line to the lode, with very little loss of the level they began from.
Where the adit is intended only for the sake of unwatering one particular
vein, it is frequently advisable to bring it home on the course of it, if the
situation of the ground will admit, because this is a continual trial of it at
that depth; yet, if there are many lodes not far asunder, an adit burrowed
home athwart them may sometimes be preferable, if it can be conveniently
complied with; for the situation of the ground must be well considered,
to judge how to drive home the most short, deep, speedy, and cheap adit,
and with the most probable success. These adits are commonly six
feet high, and about two feet and a half wide, so that there may be room
enough both in height and breadth to work in them; and, also room to roll
back the broken deads in a wheelbarrow; but, if the ground or rock be
very hard, the adit ought to be more spacious or large each way, to give the
greater liberty or room to work and break the stone. An adit requires four
men to work it constantly by day and night, and a boy or two to roll back
the broken work if they break it very fast. When the miners want air
by being a great way underground, and cannot conveniently put down
a new shaft, then, if the adit be high enough, they lay boards at the
bottom of the adit from their last shaft along to the adit end, and so
stop them down closely with clay or earth, by which contrivance, called
a saller (or soller), the boards being hollow underneath, air is conveyed to
the workmen.
"The air-pipe (a pipe with a funnel-shaped head which can be turned to
the wind when it blows from any quarter) is seldom used in adits because
the saller is more cheap and easy, the difference of expense in the air-pipe
being considerable where an adit shaft is thirty or forty fathoms deep; beside,
the saller under the workmen's feet is less incommodious than the funnel
over their heads.
"I have known an adit-end driven several fathoms at four shillings a
fathom, in Pot-grouan, that is, soft grouan; yet I have paid twelve guineas for
the same adit that we have driven many score fathoms for less than one; so
various and uncertain are the strata of the earth in these parts. The greatest
expense for the ground discovered that I ever heard of in driving an adit was
in the Old Pool Mine (about two miles from Redruth), where Mr. Basset paid
CHAP. IV.]
THE DRAINING OF MINES.
87
five-and-thirty pounds for the driving of several fathoms through one free-
stone strata."
Pryce continues with sundry remarks, mainly in praise of the perseverance
of the Cornish miners, and on the advantages frequently derived from the
liberal expenditure of time and money. He then proceeds to show that the
miners cannot go far below the adit without having recourse to some con-
trivances to remove the water from their workings. He then enumerates the
hand-pump and the force-pump, which he says will do very well for small
depths: "Next to these the water is drawn to adit, by small water-barrels,
but if the water exceeds a certain number of barrels in the course of six or
eight hours, they give over drawing by hand, and erect a whym, which is a
kind of horse-engine to draw water or work, and sometimes both, especially
in the infancy of a mine."
"Another water-engine- then frequently used-was the rag-and-chain,
which was constituted of an iron chain with knobs of cloth stiffened and
fenced with leather, seldom more than nine feet asunder. The chain is
turned round by a wheel of two or three feet diameter, furnished with iron
spikes, to enclose and keep steady the chain, so that it may rise through a
wooden pump of three, four, or five inches bore, and from twelve to twenty-
two feet long, and by means of the leather knobs bring up with it a stream
of water answerable to the diameter of the pump, and in quantity according
to the circumlocution of the wheel in any given time. A rag-and-chain
pump of four inches diameter required five or six fresh men every six hours
to draw twenty feet deep. The monthly charge of one of these engines was
not less than £50 to £60 a month; and they are now pretty generally laid
aside, on account of the great expense and the destruction of men. Never-
theless, the motion of the rag-and-chain, when it is constant, is so quick, that
it will discharge a quantity of water, even exceeding that of a wheel-and-
bob engine, whose pump is ten inches bore; and it may be usefully applied
to draw water from sundry parts, such as dippas-or little pits of a mine-
which have no communication with other machinery for the delivery of
the water to the adit. A water-wheel with bobs is yet a more effectual
engine." We learn from Mr. Pryce that the water-engine wheel at
Cooks' Kitchen mine was forty-eight feet in diameter, and worked her tier
of pumps of nine inches bore, which, first divided into four lifts, drew
from eighty fathoms under the adit. The scarcity of water in those days
was much complained of by the miners. "Happy would it be for the
mining interest, if our superficial streams of water were not so small and
scanty; but the situation of our mines, which is generally on hilly grounds,
and the short current of our springs, from their source to the sea, pre-
vents such an accumulation of water as might be applied to the purpose of
draining the mines; and of course the value of the water is the more
enhanced." When, in those days, the situation of a mine would not
admit of a water-engine, or where the stream is insufficient, "the last
resource is that most useful, powerful, and noble machine-the firc-cngine,
of which we have several that are perhaps the largest in the kingdom
(Pryce, 1778).
Mr. Joseph Carne states that the first steam-engine in Cornwall was
88
[BOOK 1.
HISTORICAL SKETCH.
erected at Wheal Vor, a mine at work from 1710 to 1714. This appears to
have been on the plan of Captain Thomas Savery.* "The Marquis of Wor-
cester, in his 'Century of Inventions,' published in the year 1663, is probably
the first that proposed converting water into steam; but Captain Savery was
the first who erected an engine for this purpose, which has been lately
improved by Mr. Blakey, though not to a degree of power sufficient to
unwater a deep mine” (Pryce).
Newcomen's patent for his atmospheric engine was granted in 1705; but
his engines do not appear to have been much known before 1712. Mr. Pryce
informs us that Mr. J. Cawley was associated with Mr. Newcomen, and that
they "contrived another way to raise water by fire: where the steam to raise
the water from the greatest depths of the mine is not required to be greater
than the pressure of the atmosphere; and this is the structure of the present
fire-engine, which is now of above seventy years' standing." Pryce then
enters into a long description of Newcomen's engine, and mentions several
improvements which had been introduced, and he gives a very useful table of
the calculation of the power of fire-engines, for the various diameters of the
cylinders and bore of the pump, or pit-barrel, that are capable of raising
water at any depth between 2 and 876 fathoms. This was calculated out
for him by Mr. John Nuncarrow, jun.
Newcomen's engine was found to be very costly, from the quantity of
coal consumed. Mr. J. Carne explains, that "notwithstanding numerous
contrivances to diminish the cost of the coals consumed in these engines,
among which there was one of a granite boiler heated by means of three
tubes passing through it, the consumption of fuel was still great, and
estimated at £3,000 per annum for engines of large size.”
COPPER.—It is impossible to determine with accuracy when copper ore
was first worked in Cornwall. Bronze vessels, weapons, and tools have
been constantly found in Cornwall; but there is no evidence existing to
show that either bronze or brass were manufactured in that county. Not-
withstanding, the fact exists, that copper, tin, and zinc are found abun-
dantly in the mineral lodes which traverse the Cornish rocks. It scarcely
appears possible that the detrital deposits of tin should have been worked
from the earliest times, without the discovery of the mineral veins from
which the stream tin had been derived. If so, they would have been sub-
jected—and probably were so-to the process of mining, and the copper
ore, which is so frequently disseminated in the same vein containing the
tin, must have been discovered, and, if discovered, it would assuredly have
been melted. It is not a little strange that, with all the attention which
has been given to the early history of tin mining, there are to be found only
a few very brief and unsatisfactory records of the discovery of copper.
The late Colonel Grant Francis has, with much industry, collected from
the stores of the Record Office considerable information, relating especially
to the commencement of copper smelting in the Swansea district. From the
"Transactions of the Geological Society of Cornwall," vol. iii. p. 50; see also "The Miner's Friend;
or, an Engine to raise Water by Fire, described, and the manner of fixing it in mines; with an account of
the several other uses it is applicable unto, and an answer to the objections made against it." By
Thomas Savery, Gent. 1702.
CHAP. IV.].
THE EARLY MINING FOR COPPER.
89
letters and other documents published by him, we gather some information
respecting the copper mines of Cornwall.*
On the 15th January, 1583, Mr. William Carnsewe writes to Mr. Smith,
commending" Mr. Weston's p'vydence in bryngyne hys Dutche myners hether
to aplye such busynys in this countrye," that is, the smelting of copper and
lead. The writer then requests that Mr. Weston's Germans may have some
men "assignyd only to them, and lett yo'r Ulryke (one Ulrick Frosse) take
such as he is now acquaintyd with of our countrymen; and the sam that
wreought in that work at Treworthye last when it was by Burchardys'
frowardniss gyvyn ov'r, w'che was abowte 23 yerys past.” Thus we learn
that smelting operations on a fairly large scale were in action before 1560, and
a thousand marks were allowed to Ulrick Frosse "for erectynge yo'r meltynge
howsys, and woody's for cole and fewell."
We learn subsequently that Ulrick Frosse was made, in 1584, "Overseer
of the Mineral Works at Perin-Sands," &c., in Cornwall. This fixes the site
of smelting works at Perranzabula, or Perran-on-the-Sands, very early. In
another letter we are told that H. Herring obtained "the owrs for xvs. the
tonne, whereof iiii. tonnes will make one tonne of copper.
The fear the
partners have, is that we shall not gett owre in any great quantitye to raise
worthy co'moditye. . . . . It appeareth y't yow have not above 50 tons
gotten in all, w'th ye w'ch you have to get 20 tonnes more before Michaelmas
next."
•
At this time we are informed that "the new melting-house at Neath,
in Wales, is ready," and that "one of o'r copper makers, with an under-
melter and ye Douch carpenter, shall be sent from Keswick," to commence
operations.
Ulrick Frosse, writing to Mr. Smith on the 22nd July, 1584, says: "Mr.
Carnsewe was here the xi. of July laste paste to se o'r workes, o'r myne here
at Perin-Sande, and wente downe with me into the bottom of the works, and
so up alongste the new audict we made, w'ch is at this present above 50
fadom longe, under all ye olde workes, but we do not lighte w'th any
owre as yet; with greate springs of water we lighte still in going up, w'ch
will put me to great charge in the end, I fear me. We have yet above
17 or 20 fadom to the deepe shafte where the most owre was left by
report, to which we thinke to com about the latter end of Augustee, with
God's helpe."
This evidently indicates that the company which Mr. Carnsewe represented
had taken up an old working, and that the promises of profit were very
unfavourable. It is not possible to fix with any certainty the mine of which this
letter speaks. It was, probably, Perran St. George. The previous letter
informs us that copper ore was raised at 15s. the ton, and that it was very
rich ore, giving 25 per cent. of copper. The quantity of copper ore obtained
was evidently very small. In another letter we read, "Wee did light w’th a
lyttle ewre at Treworth, the quantitye of all most on C waight in one nest by
itself, but cut sune out again."
Ulrick Frosse is removed from Cornwall, and becomes "Melting Master"
"The Smelting of Copper in the Swansea District, from the Time of Elizabeth to the present Day."
By Colonel Grant Francis. (Southern and Co. 1881.)
90
[BOOK I.
HISTORICAL SKETCH.
at Neath. He writes from that place, saying that the smelting operations,
"thank God, doth goe reasonably well forward, and lak but only good store
of riche owre." On October 27th, 1585, one John Otes writes: "The 14th of
October came John Bwaple, one of Wales, with his bark for a fraygte of copp'
owre, and did deliver him, the 21st of October, 15 tonn and 8 hundred of
copp' owre for Wales. The 15th October came one Thom's Roberts from
Wales, from the company, w'th a fraight of tymber and necessaryes for the
workes. I receaved his fraight at St. Ives, and for my lyffe I could not get
any owre from St. Yeust (St. Just) to St. Ives, to fraight him for Wales (Neath),
but went away w'hout any, for Bwaple would carry more owre yf I had it at
St. Ives." *
This clearly proves that the quantity of copper ore worked in Cornwall
at this time was very small. On the 7th March, 1586, Ulrick Frosse
writes Mr. Carnsewe: "We looke dayly for the copper refiner from Keswicke,
and have in readiness as much copper roste and blake copper as will make
a 20 tonne lot of good fine copper." The writer in another part of the same
letter says, "We will melt in the space of 7 houres the quantitie of 24 C of
ewre, and spend not above 8 or 9 seks of chare-coles and three horslod of
sea coles, and if the ewre be well and clean sorted, the more copper stone
will it yield; melting many sorts of ewre together is the most proffet, and
will melt a greattayal sooner."
CUMBERLAND.-The Keswick Copper Works were founded in 1566, a
company being incorporated for the purpose of working Goldscope and
Dale Head mines for copper ore.
The extensive copper smelting-works erected in 1566 were said to be
the largest in Europe. Six furnaces were in operation in 1567, chiefly sup-
plied with ore from the mines in Newlands. This work was carried on by a
colony of Germans, the chief manager being one Hockstetter.
In 1559 a
plot of ground was purchased from Mr. Curwen, of Workington, and a wharf
was built for the use of the mines and smelting-works. These continued in
active operation until 1650 or 1651, when they were destroyed during Oliver
Cromwell's campaign in the north. They were partly rebuilt by a company
of Germans about 1690, and continued working until 1715.
Goldscope has been an important copper mine since the early part of the
thirteenth century; being mentioned in the Close Rolls of Henry III. Camden
says:†"At Newlands and other places some rich veins of copper, not without
a mixture of gold and silver, were discovered in our age, A.D. 1607, by
* That_the_name (which is improperly written St. Ives for St. Ies, no one in the least conversant in
the antiquities of our country can make the least doubt of) is taken from St. Ia, I shall not now bestow my
time to prove this, for this town is to this day called by the common people in the West, Porthia (St. Iā's
Port). Leland particularly describes this town in his "Itinerary."
"The parish church is of Ia, a nobleman's daughter of Ireland, and disciple of St. Barricius. Ia and
Edwine, with many others, came into Cornwall and landed at Pendinas. This Pendinas is the peninsula and
stony rock where now the town of St. Iës standeth. One Dinan, a great lorde in Cornewaule, made a
church at Pendinas at the request of la—as it is written in St. Iës legend," &c. (Tonkin.)
The peninsula spoken of is now called "The Island," and there is unmistakable evidence that it was
an island at one time, and by that name it is distinguished in the map of the Ordnance Survey. The
island proper must be regarded as a mass of Greenstone, but the small neck of land which connects it with
the present town, is chiefly Devonian slate, overlaid by a remarkable Raised Beach, which clearly indicates
that at one period the sea flowed over this portion of land.
>>
In all probability this "island' was one of the many around the Cornish coast to which the name
of Ictus was given by Herodotus.
† Gibson's "Camden Britannica."
CHAP. IV.]
COPPER MINE AT KESWICK.
91
Thomas Thurland and David Hockstetter, a German of Anspurg, though
known many years before, as appears by the Close Rolls of Henry III.”
About these mines there was a memorable trial between Queen Elizabeth
and Thomas Percie, the Earl of Northumberland, on the question of its being
a "Mine Royal," and it was decided in the Queen's favour.
Robinson,* writing in 1709, says: "In our survey of the mountains of
Newlands we found eleven veins opened, and wrought by the Germans, all
distinguished by names given to them, as Gowd-Scalp-now Gold-Scope-
Long Work, St. Thomas's Work, &c., these being at Dale Head, about
a mile and a half south of Goldscope, of all which veins were found to
be the richest. We found the vein wrought three yards wide and twenty
fathoms deep above the grand level, which is driven in a hard rock
a hundred fathom, and only with pickaxe, hammer, and wedge, the art of
blasting with gunpowder being not then discovered. For securing of this
rich vein no cost of the best oak wood was spared, and for the recovering of
the solers under the level was placed a water-gin, and water was brought
to it in troughs of wood upon the tops of high mountains near half a mile
from the vein."
The Goldscope mine was abruptly closed in 1651, and most of the miners
were killed, or drafted into Cromwell's army. Clarke, in his "Survey of the
Lakes," says that the Dutch, who came with the Prince of Orange about
1690, began the work again, and continued it until they were driven from it
in 1715. They appear, however, to have opened the mine subsequently, for
Clarke says "they stayed until the place was not worth working."
The above passages prove the existence of copper mines-or rather of a
considerable smelting establishment, at Keswick, in Cumberland, before
1586. This appears to have belonged to the Earl of Northumberland.
Dr. Percy writes:† "In the time of Elizabeth (1558 to 1602) there was a
rich copper mine at Keswick, in Cumberland, of which that Queen deprived
the Earl of Northumberland, on the ground that it was a Mine Royal. It is
reported that not less than four thousand men were employed at this mine,
but this is probably a great exaggeration." It is certain that in the time of
Edward III. copper mines were worked at Skildane, in Northumberland, and
at Alston Moor, in Cumberland. This will carry copper mining back to
before 1377, when Edward ceased to reign. In the fifteenth year of his
reign, that was in 1541, this King granted for fifteen years the right to work
a mine of copper at Richmond, in Yorkshire, on payment of a royalty to
himself of one-eighth, and one-ninth to the lord of the soil. It appears to
have been a usual custom in those days to smelt the copper ore near the
mines, but from there being a considerable establishment at Keswick, we
may infer that ore was gathered from the copper mines of the counties
adjoining Cumberland, and smelted at Keswick as a convenient centre. It
is evident that the smelting-works at Keswick were fairly organised, for in
July of 1585, Ulrick Frosse writes, boasting "as to melting 24 cwt. of ore
every day, with one furnace, God be thanked;" and they were enabled, he
says, to send in the previous year "the copper refiner, the copper maker, the
* Robinson's "Natural History of Westmoreland and Cumberland."
+ "Metallurgy," p. 289. By John Percy, M.D., F.R.S. 1861.
92
[BOOK I.
HISTORICAL SKETCH.
under-melter, and the Dutch carpenter, to serve" at the new melting-
house at Neath, in Wales. From 1580 there appears to have been a con-
tinued importation of German miners and melters. Amongst them we find,
as managers—
Marcus Steinberger,
Richard Ledes,
Emanuel Hechstetter, or Hockstetter,
Ulrick Frosse,
Jochim Gaunse,
Daniell Houghsetter,
Christopher Schutz.
Thomas Thurland.
It is curious and interesting to find in a "Description of the Doeings of
Jochim Gaunse and George Needham, at the copper mynes by Keswicke in
Cumberland, A.D. 1581," "the nature and the number of the hurtful humours
that were naturally bred in oure copper owre gotten in that countrie.
"The names of the ix. infectyve and evill humours :—
"1. The first is sulphur, being a mineral substance which verie quickly
taketh fire, and wil be consumed in smoke by blast, &c.*
"2. The ii. corrupt humour is arsenique, by nature a kind of poyson, being
in like manner a mineral substance, wil be consumed with fire into smoke,
which is a very dangerous ayer or savor, and by his force maketh the copper
white and brether than the sulphur doeth, &c.
"3. The iii. corruption is antimony, w'ch is in like manner a mynerale
substance, and by roasting wil be consumed into smoke, &c.
. it fret-
"4. The iiii. corrupt humour is vitriall, in like manner a mynerale sub-
stance, and if the force thereof be not corrected by roasting,
teth the copper and maketh it bretle and black coulered," &c.
(Although George Needham displays in this, his very imperfect chemical
knowledge, yet we find by his rude experiments he arrives at a method
for removing this vitriall, and "thus is this vitriall of an enimye made a
friende.")
"5. The v.th corruption is calcator, being the mother or corpus of vitriall,
and a mineral substance," &c. (This is, undoubtedly,
(This is, undoubtedly, "calcother," the old
name for oxide of iron.)
"6. Allom is the vi.th corrupt humour, a myneral substance, and by
nature a let to ye smeltinge of copper.
"7. The vii.th humour is iron, being one of the vii. metals, but no
mynerale, &c.
“8. The viii.th hurtful humour that is in our copper ore is a kind of black
stone, wherein the copper is bred and doth grow.
(c
9. The ix.th and the last corrupt humour is a kind of white stone, called
sparr," &c.
The 8th and 9th "humours" are clearly rock in which the copper is found
and the quartz found in the lode.
In connection with the smelting-works at Keswick we find :—
"Whereas Mr. Steinberger, at his last being in London, made his propo-
* In each case it appears sufficient to give but a small part of the description.
CHAP. IV.]
QUEEN ELIZABETH'S LETTERS PATENT.
93
sition to the company (March, 1582), that for everie quintall of rough copper
he made (being cxii. 2), he must have vii. kebulls* of copper ore gotten
in "God's Gift mine,"† everie kebull whereof is in waite clv. li at the least,
w'ch, after a cxij. li to the hundredth, amounts to x. ciiij. xx v. li‡ of ore,
and for all manner of charges of fireworke and smelters' wages to bring the
same x. c iiij. xx v. li of ore into rough copper, he offereth to do it for
xiii. s. iiij. d."
For
At these works we learn that they had acquired the process of separating
the iron from the copper in the condition of a sulphate. The writer says:
"And yf ye cannot have utterance of so much vitriall as we can make,
then may we make of that substance copperris-which we shall make for
the dyeing of cloth—without taking any copper from the ure.
vent of this coppris ther wil be great quantitie used in Cumberland, West-
moreland, Yorkshire, Cheshire, and Lancashire only for dyeing, who are con-
strained to transporte it from London thether. And likewise ther wil be
much soulde into the North parte of Scotlande, who have often tymes both
come and sent to Keswick to buy coppris." There follows much speculation
as to the sale of this sulphate of iron in France and Spain.
Mr. George Needham, in the same letter, speaks "of the rich copper ure
gotten in the mines of Caldbeck being infected with such corruptions that
hetherto Mr. Danyell and his sonne could never melt them alone as they
came from the myne, but were forced to myngle with them roasted ure of the
first melting of 'Gode's Gift' ure." Again, the imperfections of the works or
the ignorance of the workmen is shown, as-" In like manner the rich lead
myne at Caldbeck, which houldeth good quantity of silver, and hath costt he
company great sommes of money, lieth now unwrought."
Queen Elizabeth, by her letters patent, in the sixth year of her reign, on
the 10th day of October (1564), did grant "full power, license, and authority to
Thomas Thurland, clerk, one of the chaplains and Master of the Hospital of
the Savoy; and to Daniell Houghsetter, a German born, and to their heirs,"
&c. &c., permission "to search, dig, open, roast, melt, stamp, and wash, drain
or convey waters, or otherwise work for all manner of mines or ewers
within her counties of York, Lancaster, Cumberland, Westmoreland, Cornwall,
Devon, Gloucester, and Worcester, and within her principality of Wales.
"Her Hyghnes too have for the first vi. years then next, the x.th part of
all the pure metals or ures of golld, sylver, and quicksylver, and of every C
weight of mixt ure holding viii. li or above of those rich metals to have all
the x.th part. And of Tynn, in the name of coynage, as her Ma'ti hath in
Devon and Cornwall, and of lead as in other places of the realm, and of the
Calamine the xx.th pt. or just value thereof. And of every C of copper for
the said first vi. years ii.s., or the xx.th part at her lykyng; and after those
vi. years ii.s. vi.d., or the xv.th part or value at chois aforesayd."
This document was endorsed "unto the Right Honourable Sir Francis Wall-
singham, Knight, one of the twoo Principal Secretaries, unto the Q. Ma'ti."
On the 22nd day of January, in the next year (1565), a similar "confirma-
tory charter" to one previously granted by Elizabeth was given to the
* The same name, now spelt kibals, is given to the iron buckets in which the ore is raised to the surface.
†The name of one of the mines of Caldbeck.
Ten hundredweight fourscore and five pounds.
94
[BOOK I.
HISTORICAL SKETCH.
"Mineral and Battery Works." With this, as being a purely metallurgical
company, we have less concern. It is important, however, to notice the
continued introduction of the German element. James I., in the second
year of his reign, A.D. 1604, on the 28th day of January, granted a charter
confirmatory to the Mines Royal Society. This charter commences:
"Whereas our dear late sister Elizabeth, late Queen of England, having
received creditable information that her faithful and well-beloved subjects,
William Humphrey, and her Say Master of her Mint within the Tower of
London, by their great endeavour, labour, and charges, have brought into
her realm of England one Christopher Shutz, now deceased, an Almaigne,
born at St. Annenberg, under the obedience of the Elector of Saxony, a
work master, as it was reported, of great cunning and experience, as well in
the finding of the Calamine Stone, called in Latin Lapis Calaminaris, and in
the right and proper use of the commodity called 'Laten,' and in reducing it
to be soft and malleable, and also in orpting, mannering, and working the
same for and into all sorts of battery wares, cast work, and wire, and also
in the mollifying and mannering of iron and steel, and drawing and forging
of the same into wire and plates, as well as convenient and necessary for
the making of armour, and also for divers other needful and profitable uses.'
Those German miners were the first to introduce into this country the
mystery of the Divining Rod. Borlase says, "Few of the Cornish have ever
heard of the Virgula Divinatoria and its virtue in discovering metallic lodes."
Pryce, in his "Mineralogia Cornubiensis," himself a believer in the virtues
of the Divining Rod, commonly called in that county the "Dowsing Rod,"
writes: "Hooson says that 'the first inventor of the Virgula Divinatoria
was hanged in Germany as a cheat and impostor.' On the other hand, Dr.
Diederick Wessel Linden says, in answer to him, that Dr. Stahl, when he
was president of a chemical society in this country, published a reward of
25 ducats for anybody that could prove who was the inventor of the Virgula
Divinatoria."
He then goes on to inform his readers that “Georgius Agricola, in his
excellent Latin treatise, 'De re Metallica,' says 'that the application of the
inchanted or divining rod to metallick matters took its rise from magicians
and the impure fountains of inchantment.'”
The Rod of Aaron and the rods of the Egyptian sorcerers, Mercury with
his rod Caduceus, and several other examples, might be quoted from which
the forked rod of the searcher for mineral veins, and for water, took its rise.
No mention is made of the divining-rod of the miner before the eleventh
century, since which time we often hear of it. It was much used in France
and Germany in the seventeenth century. The corpuscular philosophy was
made to account for the phenomena. The corpuscules-infinitely minute
particles were thought to rise from the mineral veins, and, entering the rod,
determine it to bow down, in order to render it parallel to the vertical lines
which the effluvia describe in their rise. "In effect, the mineral particles.
seem to be emitted from the earth. Now the virgula, being of a light porous
wood, gives easy passage to those particles, which are very fine and subtle.
* These Confirmatory Charters are printed in full by Colonel Francis, in his "Smelting of Copper in
the Swansea District."
THE DIVINING-ROD OF THE MINER.
95
CHAP. IV.]
The effluvia, then driven forward by those that follow them, and pressed at
the same time by the atmosphere incumbent on them, are forced to enter the
little interstices between the fibres of the wood, and by that effort they oblige
it to incline, or dip down perpendicularly, to become parallel with the little
columns which those vapours form in their rise" (Pryce).
Dr. William Cookworthy, of Plymouth, well known for his discovery that
the Kaolin of the Chinese was the China clay of the Tregoning and Godolphin
hills of Cornwall, gives an account of his first knowledge of the divining-rod.
The rod was introduced to him by a Captain Ribeira, who deserted
from the Spanish service in Queen Anne's reign, and became captain-com-
mandant in the garrison of Plymouth. "In which town," says Cookworthy,
"he satisfied several intelligent persons of the virtues of the rod by many
experiments on pieces of metal hid in the earth, and by the actual discovery
of a copper mine near Oakhampton, which was wrought for some years."
The captain made no difficulty about letting people see him use the rod, but
he was absolutely tenacious of the secret how to distinguish the different
metals by it, without which the knowledge of its attraction was of little use.
Pryce says he has discovered this, and made many other discoveries of
its properties, which he is willing should be published, being fully persuaded
of the great utility of this instrument in mineral undertakings.
Agricola writes: "If the attractive power of veins does not turn the rod,
when in the hands of some particular metallists or others, it is owing to
some singular occult quality in the holder, which impedes and restrains the
attractive power; for since that power moves and turns the rod in the same
manner as the loadstone invites and attracts iron, it is debilitated and
destroyed by the occult quality of the holder, just as garlic weakens and
excludes the attractive quality of the magnet, for a magnet rubbed over with
the juice of garlic does not draw iron.”* This is a statement which has no
foundation in fact.
Unless where it is stated to the contrary, the following descriptions and
directions, representing the custom of the country, are derived from Pryce.
The rod is attracted by all metals, but with different degrees of strength,
in the following order :-1, gold; 2, copper; 3, iron; 4, silver; 5, tin; 6, lead;
7, coal; 8, Limestone and springs of water. Pryce gives the following
experiment. Stand holding the rod, with one foot advanced; put a guinea
under that foot and a halfpenny under the other. The rod will be drawn down.
Shift the coins, and the rod will be drawn towards the face or backwards to
the gold, which proves the gold to have the stronger attraction.
The divining-rods formerly used were shoots of one year's growth that
grew forked; but two separate shoots tied together with some vegetable
substance, as packthread, will answer better than those which are grown
forked. As the shoots are seldom of equal length or bigness, they do not
handle so well as the others, which may be chosen of exactly the same
size. The rods should be between two and three feet long. They must be
tied together at their great or root ends, the smaller being held in the hands.
Hazel rods cut in the winter, such as are used for fishing-rods, and kept until
they are dry, appear to answer the best. Apple-tree suckers, rods from
* Georgii Agricolæ, "De 1e Metallica." Basilex. MDLVI.
96
[BOOK I.
HISTORICAL SKETCH.
peach-trees, currants, or the oak, though green, will answer tolerably well.
Of late years a forked twig cut from a black thorn has been regarded as the
most sensitive rod. Pryce says it is difficult to describe the manner of holding
the rod, so he has given an illustrative drawing, which we copy, Fig. 11. We
shall endeavour, however, to give some idea of the mode of holding the rod.
The operator stands with his arms extended and the hands wide open;
an assistant places the twig, or arm of the fork, in each hand, flat upon the
palm; the four fingers of each hand are now closed upon the ends of the fork.
It is perfectly easy thus to hold the rod; but although in the drawing given from
الااك
Agricola, Fig. 10, it does not
appear as if the rod was held
in any particular manner, the
drawing given by Pryce shows
the difficulty of adopting the
proper position. The four
fingers being closed upon the
rod, and the rod held firmly,
without allowing it to move,
the point is by a movement
of the hand turned up to-
wards the face, and then
down and round, so that the
point of the rod is in front of
the operator. It will, we
think, be evident from this
that a very severe twist or
strain is given to the wrist,
and that consequently the rod
is held in a state of extreme
tension. With the arms in
this condition, and with the
mind fixed on the discovery
of a mineral vein, the opera-
tor becomes conscious of a
slight tremor, the result of
muscular action. The muscles,
by an automatic effort, endea-
vour to relieve themselves
from the strain. There is a
tendency, too, in the first instance to resist this, and consequently the
fork of the rod is moved either up or down, and it is declared to be active.
Even in Pryce's drawing the constrained position of the hands is only
indicated by the flexure of the rod.
Fig. 10.-Facsimile from Agricola.
With the figures we hope the above description may serve, especially
after reading the following extract from Pryce: "The rod being properly
held by those with whom it will answer, when the toe of the right foot.
is within the same diameter of the piece of metal, or other subject of the
rod, it will be repelled towards the face and continue to be so, while the foot
MODE OF USING THE DIVINING-ROD.
97
is kept from touching, or being directly over the subject, in which case it will
be sensibly and strongly attracted and be quite drawn down. The rod.
should be firmly and steadily grasped; for if when it hath begun to be
attracted there be the least imaginable jerk or opposition to its attraction, it
will not move any more till the hands are opened and a fresh grasp taken.
The stronger the grasp the livelier the rod moves, provided the grasp be steady
and of an equal strength. This observation is very necessary, as the opera-
tion of the rod in many hands is defeated purely by a jerk or counter-action,
and it is from thence concluded that there is no real efficiency in the rod, or
that the person who holds it wants the virtue; whereas by a proper attention
to this circumstance in using it, five persons in six have the virtue, as it is
called that is, the nut or fruit bearing rod will answer in their hands. When
the rod is drawn down, the hands must be opened, the rod raised by the
middle fingers, a fresh grasp taken, and the rod held again in the direction
described."
Pryce continues, giving some instructions which are entirely at variance
with the hypothesis that electricity, magnetism, or any such force is active
M D
Fig. 11.-The Divining-Rod.
in producing the phenomena. "If a rod, or the least piece of one, of the
nut-bearing or fruit kind, be put under the arm, it will totally destroy the
operation of the Virgula Divinatoria in regard to all the subjects of it, except
water, in those hands in which the rod naturally operates. If the least
animal thread, as silk, or worsted, or hair, be tied round or fixt on the top of
the rod, it will in like manner hinder its operation; but the same rod
placed under the arm, or the same animal substances tied round or fixt on
the top of the rod, will make it work in those hands in which, without these
additions, it is not attracted. All rods, in all hands, answer to springs of
water.
""
The same author tells us that gold or copper held in the hand hinders the
rod from being attracted by either of those metals. If iron, silver, lead, or
tin be held in the hand, the rod will not be attracted by these metals, but
repelled. It appears that rods may be prepared for distinguishing the white
metals, by boring with a gimblet a hole in the top of the rod, and putting
therein a mixture, in powder, of coal, bones, iron, lead, tin, and copper. If
H
S
98
[BOOK I.
HISTORICÀL› SKETCH.
the red or yellow metals are to be distinguished, the copper filings are to
be left out.
Now we arrive at Pryce's directions for using the rod. "The rod
being guarded against all subjects except that which you want to discover,
-as tin and copper, for example-walk steadily and slowly on with
it; and a person that hath been accustomed to carry it, will meet with a
single repulsion and attraction every three, four, or five yards, which must
not be heeded-it being only from the water that is between every bed of
Killas, grouan, or other strata. When the holder approaches a lode so near
as its semi-diameter, the rod feels loose in the hands, and is very sensibly
repelled towards the face. If it is thrown back so far as to touch the hat, it
must be brought forward to its usual elevation, when it will continue to be
repelled till the foremost foot is over the edge of the lode. When this is the case,
if the rod is held well, there will first be a small repulsion towards the face, but
this is momentary, and the rod will be immediately drawn irresistibly down,
and will continue to be so in the whole passage over the lode; but as soon
as the foremost foot is beyond its limits, the attraction from the hindmost
foot, which is still on the lode, or else the repulsion on the other side, or
both, throw the rod back toward the face. . . . . We must then turn and
trace it on obliquely, or in the way of zigzag, as far as may be thought
necessary. In the course of tracing a lode, all the circumstances of it, so far
as they relate to its back, will be discovered; as, its breadth at different
places,—its being squeezed together by hard strata,—its being cut off and
thrown aside from its regular course by a cross gossan," &c.
All particulars respecting the use of the divining-rod for the discovery
of lodes, by one who was a firm believer in the "virtues," as he calls
them, of the rod, have now been given. It remains only to examine the
conditions involved in the use of it. Pryce says: "A little practice by
a person in earnest about it will soon give him the necessary adroitness
in the use of this instrument; but it must be particularly observed that as
our animal spirits are necessary to this process, so a man ought to hold the
rod with the same indifference and inattention to, or reasoning about it,
or its effects, as he holds a fishing-rod or a walking-stick; for if the mind be
occupied by doubts, reasoning, or any other operation that engages the
animal spirits, it will divert their powers from being exerted in this process,
in which their instrumentality is absolutely necessary. From hence it is,
that the rod constantly answers in the hands of peasants, women, and
children, who hold it simply, without puzzling their minds with doubts or
reasonings."
Certain trees, especially fruit-bearing ones, are supposed to be imbued
with some influence, similar to that of a magnet, and to turn by virtue of
that influence towards mineral lodes of any kind, as a magnet is attracted by
a mass of iron. The advances of science have made us acquainted with two
forms of this subtile force-the one the true magnetic force, which causes the
compass-needle to turn to iron and two or three other metals; and the
other, the dia-magnetic force, which appears to act on all bodies except iron
by repelling them. The first question which arises is, therefore, Does either
of these forms of force act on the divining-rod?
CHAP. IV.]
HYPOTHESES OF THE ROD EXAMINED.
99
The hypothetical influence is usually supposed to be some form of
electrical energy. We are instructed by the researches of science that
currents of electricity are constantly flowing around this planet, origi-
nating at the points on which the sun's rays fall in the morning-arriving
at their maximum when the sun is highest in the heavens-and gradually
declining as the sun reaches the western horizon (Faraday). Reflection on
all the conditions will show that this power must be regarded as a diffusive
force, enveloping all forms of matter, and that it is thrown into undulatory
motion by the solar rays, or, it may be, disturbed by any mechanical power.
It has been supposed that the metalliferous veins were good conductors of
electricity, and the experiments of Mr. Robert Were Fox especially have
been adduced in favour of the hypothesis that mineral veins were the
channels through which electricity flowed freely. But the author's experi-
ments underground, in the Cornish mines, established the fact that no elec-
tricity could be detected in the mineral lodes-unless they were under-
going a chemical change. Strong currents of electricity could sometimes
be detected, but never unless the mineral matter was decomposing,
and the electricity measured was an exact representation of the amount
of chemical change taking place. The experiments of Mr. J. A. Phillips
also support this view.*
If any of the divining-rods, even the most sensitive, be placed above
metals or the most active mineral lodes-the rod being most delicately
balanced-not the slightest indication of any action will be detected; there-
fore the supposed influence is not exerted between the rod and the lode. It
must be sought for in the individual who bears the rod. Mr. Pryce distinctly
intimates that the ignorant, and the untrained, and the impulsive peasant
women and children are the best agents to work with; therefore we may
venture to infer that the power which bends the rod is from within the holder,
and not from without. It is no terrestrial influence. Is it some agency
interpenetrating the organised structure? All evidence is against this being
possible. The mind only is the power, to the influence of which the rod
answers. With a fixed idea that sooner or later the divining-rod is to bend in
the hands of the operator, he walks over a ground supposed to contain
mineral lodes. Be it remembered, that the rod is held in a most constrained
position—the muscles of the arms being brought into a state of extreme
tension;—and a trial will show that there is a continually increasing desire
to relieve the arms by moving the rod. This is often an automatic action,
of which the operator is unconscious.
Happily there are now but very few persons who will trust the uncertain,
the capricious action of the divining-rod. There are a certain number of men
and women who are disposed to place confidence in the assertions of the
ignorant or of the wilful deceivers. We solicit the attention of such to the
well-weighed words of the true philosophers-Faraday, Carpenter, and others
-who regard the phenomena of the divining-rod, and of table-turning, as
the result of mental influences wrongly directed.
It is very important to ascertain, with the utmost possible accuracy, the
quantity of ground removed by the, in many respects rude, processes of
* Reports of the Royal Cornwall Polytechnic Society.
4
H 2
100
[BOOK I.
HISTORICAL SKETCH
mining carried on in the eighteenth century. Pryce is one of our best guides
in this matter; therefore, although the mechanical conditions under which
mining is now carried out will form the subject of consideration in the
second section of this volume, it is intended to borrow from that author some
remarks which appear important up to 1778.
Pryce supposes the average produce of the county to be three hundred-
weight of tin in one hundred sacks of tin stuff. Allowing one sack to
weigh one hundred and a quarter, then one hundred sacks will be six tons
five hundredweight; consequently there must be one ton of tin produced out
of forty-one tons thirteen hundredweight. The county has been found to
produce annually, for some few years past, about three thousand tons of pure
tin metal, which, multiplied by forty-two tons of tin stuff, as above, gives the
total sum of one hundred and twenty-six thousand tons of tin stuff per
annum.
Mr. Carew, in the time of Queen Elizabeth, says: "It is found in sundry
places, but to what gain to the searchers I have not been curious to inquire,
nor they hasty to reveal; for of one mine of which I took a view, the ore
was shipped to be refined in Wales, either to save the cost or to conceal
the profit."
Mr. Norden, at the commencement of the seventeenth century, gave much
information respecting the Cornish copper mines, and in a letter to King
James I.* says: "So rich are the works, especially some lately found, as by
the opinion of the skilful in the mystery the like have not been found else-
where, though the worth hath been formerly exterminated by private pryers
into the secret, and covertly followed for their own gain."
Pryce, writing in 1778, says: "Notwithstanding those hints, we do not
find anything material going on here as to the improvement of the copper
mines, till about eighty years since some gentlemen of Bristol made it their
business to inspect our mines more narrowly, and bought the copper ores for
£2 10s. to £4 per ton. . . . This encouraged other gentlemen of Bristol,
about sixty years since, to covenant with some of the principal miners in
Cornwall to buy all their copper ores for a term of years at a stated low
price; particularly with Mr. Beauchamp, the grandfather of the present John
Beauchamp, Esq., to buy all the copper ore which should rise out of a
mine, well stocked, for twenty years, at £5 per ton, and the ore of Relistian,
in Gwinnear, was covenanted for at £2 10s. per ton.
“About fifty years back large quantities of copper ore were taken from
three principal mines in this county, viz. Huel Fortune, in Ludgvan ;
Roskear, in Camborne; and Pool-Adit, in Illogan, the produce of which
mines were sold to the few buyers at their own prices.
"The four copper companies at this time were :—
"I. The Brass Wire Company.
((
2. The English Copper Company.
"3. Wayn and Company.
<<
4. Chambers and Company."
Pryce states that at this time the confederated companies "were inter-
rupted by a gentleman from Wales, who visited this county, in order to
* Norden's "Survey of Cornwall."
CHAP. IV.]
ton.
THE EARLY PRODUCTION OF COPPER.
ΙΟΙ
improve his own branch of business in the same way." He then tells us
"that 1,400 tons of copper ore had been lying unsold some years at Roskear
and Huel Kitty, for which the confederate buyers would give only £4 5s. per
However, this gentleman bought the 1,400 tons of ore at the
advanced price of £6 5s. per ton, which he paid for with ready money, and
gained much above 30 per cent., as the writer is well informed from the most
indubitable authority." Beyond this, "this new comer bought 900 tons
more at Roskear, at £7 per ton, and in less than six months before he left
Cornwall he purchased 3,000 tons, upon which he deservedly made very
little, if at all, short of 40 per cent. profit."
The following statement, drawn up by Colonel Grant Francis,* was
communicated to The Cambrian newspaper on the 22nd September, 1868-
"Works were first erected upon the river of Swansea for smelting copper
and lead in the year 1717.
"At Aberavon, by Newton and Cartwright, 1727.
"At Penclawdd, by John Vivian, 1800.
"At Llanelly, by Daniel, Nevile, and others, 1805.
"At Laughor, by Morris and Rees, 1809.
"At Pembrey, by Mason and Elkington, 1846.
"At Bank-y-Gochus, at Swansea, in 1719;-passed into the hands of
Lockwood, Morris, and Co., 1827.
"Thomas Coster and partners erected a copper works at Red Brook on
the Wye, in 1700. He soon made a profit of £60,000.”
The system of selling copper ores by public sale to the highest bidder
was introduced shortly after the above transaction. The buyers and sellers
mutually agreed to "ticket" for all copper ores which should at stated
periods be ready for sale. Each purchaser wrote on a ticket the sum which
he was prepared to give per ton for each sample of ore offered, and this
ticket was handed to the clerk of the court; and when each buyer had
handed in his ticket they were read over, and the highest bidder was declared
the purchaser of the copper ore. Pryce says: "According to the following
accounts, which are faithfully transcribed from the copper ore buyers' book,
we find the quantity sold from 1726 inclusive to the end of 1735, was 64,800
tons, at an average price of £7 15s. 10d. per ton, amounting to £473,500,
which must have been yearly £47,350. From 1736 inclusive to the end of
1745, 75,520 tons of copper ore were sold at £7 8s. 6d. average price,
amounting to £500, 106 in the gross, £65,010 yearly. From 1746 inclusive
to the end of 1755, the quantity sold was 98,790 tons, at £7 8s. the ton,
amounting to £731,457, annually £73,145. From 1756 inclusive to the end
of 1765, the quantum sold made 169,690 tons, at the average price of
£7 6s. 6d., amounting to the sum of £1,243,045, and £124,304 yearly. Lastly,
from the end of 1766 to the end of last year, 1777, 264,273 tons of copper ore
were disposed of at £6 14s. 6d. per ton, amounting in all to £1,778,337,
which must have returned £177,833 every year of the last ten."
We have the satisfaction of being enabled to print on next page a ticket-
ing paper of ores sampled at Redruth on the 3rd April, 1781. That was ten
years later than when the above statement was made.
* "The Smelting of Copper in the Swansea District." By Colonel Grant Francis.
102
[BOOK I.
HISTORICAL SKETCH.'
Ores Sampled 3rd April, 1781, and Sold the 17th instant.
Tons.
Hore.
Bevan.
Phillips. Williams.
Smith.
Bennallack. Edwards. Ennis.
Dicken-
son.
Stephens. Carkeet.
Warren.
Wilson.
United Mines
92
£ s. d. £
II 3 6
s. d. £ S. d. £ s.
10 8 0 10 4 0
10 12
d.
6
£ S. d.
9 17 6
£
s. d.
10 5 6
£ s. d.
£
10 4 6
s. d.
9 16 0
£
s. d. £
IO IO 6
s. d.
ΙΟ O O
77
6 10 6
6 10 0
5 18 6
636
5 14 0
6 18 0
67 6
5 14 6
6 16 6
IO
5 10 O
70
13 5 6
II
2 6
II II O
12 9 6
II 7 6 12 o o
II II 6
II 8 0
II 14 6
II IO O
69
13 5 6
II
2 6
II II O
12 9 6
II 4 6
12 O O
II II 6
II 8 0
II 14 6
*I I
O O
41
IO 16 O
10 4 0
9 90
10 3 6
9 7 6
10 5 6
9 17 6
9 10 6
IO
2 0
9 IO O
34
8 7 6
7 18 6
7 15 0
719 6
7 6 0
7 16 O
7 16 0
7 12 6
8 26
Tresavean
7 12 O
76
7 17 0
8 8 6
7 18 6
7 8 6
7 12 0
8 4 6
8 20
7 15 0
8 7 6
7 12 0
37
4 13 0
536
5 5 6
5 0 0
4 6 6
4 7 6
4 7 0
4 19 6
4 16 6
Poldice
4 10 6
34
4 14 O
4 II 6
4 8 0
490
4 I O
3 19 6
4 4 6
4 14 O
4 10 6
4 0 0
24
5 11 6
5 19 0
5 16 6
5 8 0
5 I o
566
5 13 0
5 12 0
5 17 6
59 0
21
4 5 6
5 II
6
4 15 O
4 13 6
4 7.6
3 19 6
4 18 6
4 18 6
4 16 6
4 7 6
17
4 14 O
566
4 8 0
490
4 I O
5 20
52 6
4 14 O
4 13 0
4 4 0
Tons
392
306
138
37
77
34
CHAP. IV.]
COPPER SMELTING IN CORNWALL.
103
Tonkin fixes the discovery of the value of copper ore in Cornwall
within sixty years of the time of his writing his notes to Carew's "Survey,"
which appears to have been about 1739-that will be about 1679. He says:
"Copper has turned to very great account in this county, and there have
been very great discoveries made therein, both in the eastern and western
parts." After describing the various kinds of copper ore raised, he says:
"The solid ore is more frequent, and also very rich in metal. In some
places, too, viz. Wheal Rose in St. Agnes, Crowan Downs, Trevascus in
Winnier, &c., they meet sometimes with ore so rich as to be malleable;
sometimes powdered with sparks throughout with virgin copper, and some-
times with the same in leaves." Tonkin evidently intends to speak of the
pure sulphide of copper (grey copper ore). After stating that the copper-ore
buyers sent their ores to Wales to be smelted, that they might hide their
profits, he goes on to state that about thirty years previously—that will
be about 1700-"the late John Pollard and Mr. Thomas Worth, jun., of
St. Ives, and before them Mr. Scobell, at Pol Ruddan, in St. Austell, with
whom Sir Thomas Clarke and old Mr. Vincent joined (in putting up furnaces
for copper smelting), were the first to produce a piece of copper in this
county, smelted and refined and brought to perfection. But these attempts
failed of success, more through ill-management, roguery of the workmen,
and the ill situation of the said smelting-houses, than any defect in the
ore or charge of the fuel.”
Tonkin then informs us that one Gideon Collier, of St. Piran-in-the-Sands,
erected a house for the like purpose at Penpol, in the parish of Phillach, which
on his death passed into the hands of Sir William Pendarves and Robert
Corker, who were for several years successful copper-smelters. At Leno-
brey, in St. Agnes, a smelting-house was put up, but for want of capital it
failed. In Pryce's time there were several copper-smelting companies in
Cornwall—one at Hayle, established by Mr. Sampson Swaine, which con-
tinued in action until within the last twenty years; another at Entral, in
the parish of Camborne; another at Tregewe, on the Falmouth estuary, which
had been first established at North Downs, near Redruth. There is good
evidence to prove that the adventurers of Dolcoath at one period, probably
at the time when the German Rodolph Raspe* was connected with that
* This remarkable man, Rodolph Eric Raspe, was the author of Baron Munchausen's wonderful
adventures. The following notice of him will be of interest :—
"The author of the Baron's wonderful adventures is now ascertained to have been Rodolph Eric
Raspe, a learned and scientific German, who died in the latter part of 1794 at Mucross, in the south of
Ireland, while conducting some mining operations there. Much there was of both good and ill about
poor Raspe. But yet let the truth be told. Be it known, then, that this ingenious man-who was born
in Hanover, in 1737-commenced life in the service of the Landgrave of Hesse Cassel, as Professor of
Archæology, Inspector of the Public Cabinet of Medals, Keeper of the National Library, and a
councillor, but disgraced himself by putting some of the valuables entrusted to him in pawn, to raise
money for some temporary necessities. He disappeared, and was advertised for by the police as Councillor
Raspe, a man with red hair, who usually appeared in a scarlet dress embroidered with gold, but some-
times in black, blue, or grey clothes. He was arrested at Clausthal, but escaped during the night, and
made his way to England, where he chiefly resided for the remainder of his days.
"Raspe had manifested decided talents in the investigation of questions in geology and mineralogy.
He published in Leipsic, in 1763, a curious volume in Latin on the formation of volcanic islands, and the
nature of petrified bodies. In 1769 there was read, at the Royal Society in London, a Latin paper of his
on the elephantine and other animals found in North America, and it is surprising at what rational and
just conclusions he had arrived.
"The exact time of the flight to England is not known, but in 1776 he is found publishing in London
* "Biographie Universelle."
104
[BOOK I.
HISTORICAL SKETCH.
mine, smelted their own copper ore.
On the eastern side of the present
counting-house, rectangular blocks of copper slag are built into the wall,
and upon inquiry I find those were found amongst the waste-heaps of the
mines, and that a considerable number are still buried in this débris.
The following letter, written by Mr. Thomas Williams to Lord Uxbridge,
on the 6th August, 1785-especially endeavouring to adjust the difficulties
a volume on some German Volcanoes and their Productions, necessarily extinct volcanoes, thus again
showing his early apprehension of facts then little, if at all, understood, though now, familiar. And in the
ensuing year he gave forth a translation of the Baron Born's travels in Tamesvar, Transylvania, and
Hungary, a mineralogical work of high reputation. In 1780 Horace Walpole speaks of him as a Dutch
savant,' who had come over here, and who was preparing to publish two old manuscripts in infernal
Latin,' on oil painting, which proved Walpole's own idea that the use of oil colours was known before the
days of Van Eyck. He is poor,' says the virtuoso of Strawberry Hill; the natural sequel to which
statement is another three months later, 'Poor Raspe is arrested by his tailor. I have sent him a little
money,' adds Walpole, and he hopes to recover his liberty, but I question whether he will be able to
struggle on here.'* By Walpole's patronage the book was actually published in April, 1781.
+
"
"In this year Raspe announced a design of travelling in Egypt, to collect its antiquities;
but while the scheme was pending he obtained employment in certain mines in Cornwall. He was
residing as storemaster at Dolcoath mine in that district when he wrote and published his Travels of
Baron Munchausen.'+ Previously to this time, his delinquency at Cassel having become known, the
Royal Society erased his name from their honorary list; and he threatened in revenge to print, in the
form of their Philosophical Transactions,' the Unphilosophical Transactions of the English Savans, with
their Characters.' This matter seems to have blown over. And now we have to introduce our hero in a
new connection with English literature. The facts are fully known to us, and there can be no harm in
stating them. Be it understood, then, that Raspe paid a visit to Scotland in the summer and autumn of
1789, for the professed purpose of searching in various districts for minerals. It was announced in the
'Scot's Magazine' for October that he had discovered copper, lead, iron, cobalt, manganese, &c.; that the
marble of Tiree, the iron of Glengarry, and the lead of the Breadalbane property, were all likely to turn
out extremely well. From Sutherland he had brought specimens of the finest clay; there was 'every
symptom of coal,' and a fine vein of heavy spar had been discovered. He had now begun his survey of
Caithness. From another source we learn that a white saline marble in Icolmkill had received his
attention. As to Caithness, here lay probably the loadstone that had brought him into Scotland—in the
person of Sir John Sinclair, of Ulbster, a most benevolent gentleman, who, during a long life, was
continually engaged in useful projects, chiefly designed for the public benefit, and of novel kinds. With
him Raspe took up his abode for a considerable time at his spray-beaten castle on the Pentland Firth, and
the members of the family still speak of their father's unfailing appreciation of the infinite intelligence
and facetiousness of his visitor's conversation. Sir John had some years before discovered a small vein of
yellow mundic on the moor of Skinnet, four miles from Thurso. The Cornish miner he consulted told
him that the mundic itself was of no value, but a good sign of other valuable minerals not far off. In
their peculiar jargon, 'White mundic was a good horseman, and always rode on a good lode.' § Sir John
now employed Raspe to examine the ground, not designing to mine it himself, but to let it to others if it
should turn out favourably. For a time this investigation gave the proprietor very good hopes. Masses of
a bright heavy mineral were brought to Thurso Castle as foretastes of what was coming. But in time the
bubble burst, and it was fully concluded by Sir John Sinclair that the ores which appeared were all
brought from Cornwall and planted in the places where they were found. Miss Catherine Sinclair has
often heard her father relate the story, but never with the slightest degree of bitterness. On the contrary,
both he and Lady Sinclair always said that the little loss they made on the occasion was amply compen-
sated by the amusement which the mineralogist had given them while a guest in their house.
"It will be observed that in his mining operations in Caithness he answers to the character of Douster-
swivel, in 'The Antiquary,' and there is every reason to believe that he gave Scott the idea of that
character. Albeit, the Baronet of Ulbster did not prove to be so extremely imposed upon as Sir Arthur
Wardour was."
In the Library of the Museum of Practical Geology are the following works by Rodolph Eric
Raspe :-
I. Specimen Historia Naturalis Globi Terraquei præcipue de novis e Mari natis Insulis." 8vo.
Amster et Leipsiæ, 1762.
2. "Beytrag zur allerältesten und natürlichen Historie von Hessen; oder Beschreibung des Habich-
waldes und verschiedner andern Niederhessischen alten volcane in der Nachbarschaft von Cassel." 8vo.
Cassel, 1774.
3. "An Account of some German Volcanoes and their Productions, with a new Hypothesis of the
Prismatic Basalts." 8vo. London, 1776.
4. "A Descriptive Catalogue of a General Collection of Ancient and Modern Engraved Gems cast in
Coloured Pastes," &c. 2 vols. 4to. London, 1791.
Also translations by Raspe of "Born's Travels through the Banat of Tamesvar, Transylvania, and
Hungary." 1770. "Born's New Process of Amalgamation of Gold and Silver Ores and other Metallic
Mixtures." 4to. London, 1790. "Ferber's Mineralogical History of Bohemia." 8vo. London, 1777.
* See Index to Walpole's Correspondence. + "Gentleman's Magazine," November, 1856.
Walker's "Econ. Hist. of Hebrides," ii. 379. § "Statistical Account of Scotland," xx. 538.
See Chambers's "Book of Days."
CHAP. IV.]
WILLIAMS'S LETTER ON THE COPPER TRADE. 105
which had arisen from the large production of the Anglesea mines-will be
of interest in the history of the copper trade :-
"MY LORD,
"LONDON, August 6th, 1785.
"I have been so hurried I cou'd not until now sit down to give you
that state of the Cornish business which I wished to do.
"The real state of the Cornish and Anglesey Mines for the last 7 years
has been this :-
"The former in the year 1778 produced of ore 24,536 Tons. In 1784,
37,288. In all the 7 years 209,713, which make nearly 30,000 Tons p. Ann.,
yielding about 3,750 Tons of Copper each year.
"The Tonage of the Anglesey Ores as raised was not much inferior in
the same time, but being in that state of a very low produce the Quantities
were reduced to one third of their original Tonage or thereabouts when sent
to be smelted, and according to the best calculation I can make, the
Copper produced from thence, 7 years ago (I mean both Mines) did not
exceed 1,200 Tons at most. They produced this last year, I believe, about
2,300 Tons of Copper, and Cornwall produced about 4,700 Tons of Copper.
Through Oppositions and Competitions at Market these properties
were sold full 20 p. cent. under their value, to the very great injury of all
persons interested therein.
66
"The Cornish Ores were sold to 11 different Copper Companies to be by
them smelted and brought to Market in the metal. Those Companies
sometimes combined together to run down the value of the Anglesey
Copper. At others, they differed amongst themselves, yet always agreed in
beating down the price of the Ores in Cornwall, and buying cheap there,
they were enabled to sell the Metal at a low price, and we were obliged to do
the same, or be beat out of all the Markets.
"I remonstrated on this to the Cornish Miners 4 years ago, and urged
them to smelt their own ores and bring their metal to Market with us-their
Interest and ours being exactly the same. They acknowledged the expe-
dience of such a measure, but declared themselves unequal to the under-
taking, for want of money, and tamely suffered the impositions until about
2 months ago, when they were roused to a due sense of them. Resolved to
smelt their own Ores and applied to us to come to terms with 'em in the sale
of our Metals at the same price and in reasonable proportions according to
the produce of each Country whenever the Quantities should render such a
regulation necessary to prevent the price from falling by means of a glut at
Market. While we can get sales at a fair price, each to make the most of
their property without any regard to proportions or Quantities—yet to guard
against the Fall of prices through over Quantities at Market it was thought
expedient on such an event to have certain specific Terms to resort to.
"The substance of the agreement proposed to be entered into betwixt
the Cornish and Anglesey Miners, is as follows:-
"Ist. That all the Ores of both Countries be smelted by the Owners or
Lessees, and the Metal sent to one general warehouse in London, Liverpool,
Bristol, and Birmingham, to be from thence sold, &c. The two parties not
to be connected in any sort of partnership, or have any accounts with each
106
[BOOK I.
HISTORICAL SKETCH.
other unless in borrowing metal from each other as their exigencies may
require-and though the different properties are under one roof they are to
be in different apartments. No mixture of property to take place on any
account—but each party to put their property under the care of their own
separate Agents.
"2nd. To prevent jealousies or suspicions, the Books of both parties to
be subject to the inspection of a Committee of 5 merchants to be appointed
to govern and direct the trade for the mutual benefit of each party, whenever
any differences arise amongst themselves.
(6
'3rd. That to avoid the necessity for a meeting of the Committee but
upon Extraordinary occasions, an Agent for both parties shall be appointed
to direct the general course of the Trade-but if either party be dissatisfied
with his conduct, Appeal to be made to the Committee, whose determination
shall be final.
"These are the outlines of the Connection, but subject to such other
regulations as may from time to time be thought necessary for the general
advantage of the trade. There are numberless minutiæ of this great Concern
necessary for your Lordship's Information, but I must beg leave to defer
them till I have the honor of waiting upon you at Beau-Desert, which will
be ere long. In the meantime I only beg you may rest assured this Cornish
connection cannot do any Injury to the Anglesey Miners, but may afford
them very great advantages.
“I am, my Lord, with all due respect,
"Your Lordship's most obliged and faithful Servant,
"T. WILLIAMS."
On the 20th of April, 1799, Mr. Thomas Williams, M.P., gave evidence
before "The Committee appointed to inquire into the state of the Copper
Mines and Copper Trade of the United Kingdom," to the following effect:
"It was not until the end of the last century that copper ore was first dis-
covered in Britain, and that was in working the tin mines of Cornwall, which
had been wrought time immemorial." (This witness evidently knew nothing
of the discovery of copper by the Romans.)
"Soon after that discovery, viz. in 1691, a charter was granted to Sir
Joseph Herne and other merchants of London, who were thereby incorpo-
rated as a company for the purposes of refining and purifying copper ores
under the firm and title of 'The Governor and Company of Copper Miners in
England,' now commonly called 'The English Copper Company.' In
1694 a copper coinage of halfpence and farthings took place, and Govern-
ment paid at the rate of 18d. a pound for the copper, which was of Swedish
production. In 1717 a further coinage took place to the amount of 700 tons.
of English copper, for which the Government paid at the rate of 15 d. per lb.,
or £147 per ton. In 1702 the first brass work was erected near Bristol, which
has continued to this time (1799).
"For the first twenty or thirty years of the present century, and always
before, most of the copper and brass utensils for the culinary and other pur-
poses of this country were imported from Hamburg and Holland, procured
from the manufactures immemorially established at Nuremberg and various
CHAP. IV.]
WORKING MINES ON TRIBUTE.
107
other parts of Germany. Even brass pans for the purposes of the dairies of
our county could not be procured but of German make. So late as 1745,
1746, and 1750, copper teakettles, saucepans, and pots of all sizes were
imported here in large quantities from Hamburg and Holland.”
About this period the custom of setting or leasing a mine on tribute
came into use. Some able miner takes the mine of the adventurers for a
determined time, that is, for half a year, a whole year, nay, even for seven
years, as was the case at Bullen Garden, and the means of her discovery.
Pryce thus describes the rules by which this custom was regulated :—
"If it is a tin mine, he articles first to pay the lord, or the lords and
bounders, if any, their shares or doles, free of all cost, in the stone made ready
for the stamping-mill. This must be such a proportion of all tin stuff as shall
be raised during the limited time. Of the remainder he pays the adventurers
one moiety, or one-quarter part, according to the agreement, it being more
or less in proportion to the richness of a mine. For example, in a tin mine
not bounded, the lord grants for, perhaps, one-seventh. Now the tin stuff,
when it is properly sized to stones not larger than a man's fist, is divided into
seven doles or piles. The lord's agent, steward, or toller, casts lots upon
these doles by written tickets-six marked A and one L, and which of
them falls to his lot L, on that dole he puts the turf, and upon the turf a stone.
Three and a half of the six A doles remaining may belong to the tributor,
and the other two and a half to the adventurers, which also is transacted by
dividing and casting lots as before. Where a tin mine is in wastrel and
bounded, the manner of dividing and casting lots is more complex.
"In most tin bounds the lord's part is one-fifteenth of the whole, and the
bounder's part is one-twelfth, commonly only one-tenth of the remainder.
For instance, the tin stuff is divided into fifteen doles, one of which is marked
by the lord's agent, as above, after the lots are cast. Then fourteen doles
remain, two of which are equally subdivided and carried to the other twelve.
One of these, by lot as before, belongs to the bounders, and that very likely
must be subdivided again and again, it being for the most part the property
of several persons.
"Of the eleven doles to be divided among the adventurers and the tributor
according to the article of their agreement, the adventurers shall have three
doles and one-quarter of a dole, and the tributor seven doles and three-
quarters. They then cast eleven lots, viz. three marked A, and seven marked
T, and one blank, and where the blank falls that dole is redivided into four
parts, and lots are recast upon it; one A the adventurer's part, and the T the
tributor's. This, however, is not all. The adventurer's three doles and a
quarter are again divided into eighths, sixteenths, thirty-seconds, and sixty-
fourths, and even much smaller fractions, that each may know and carry
away his own.
"The tributor, again, may have several persons concerned with him, who
redivide their seven doles and three-quarters in like manner; and thus are
these fractional complicated divisions, which at first sight would puzzle the
most expert arithmetician, effected by our illiterate tinners upon the simplest
plan, and with the utmost dexterity, dispatch, and accuracy.
"The setting of a copper mine upon tribute has this difference. The
108
[BOOK I.
HISTORICAL SKETCH.
tributor is at the sole expense of digging, raising, and dressing all the ore
that can be made merchantable; and the proceeds of sales are received by
the adventurers, who pay the lord his one-seventh, one-eighth, or one-tenth
part, whichever it is, in money. If it is one-eighth, that is two shillings and
sixpence out of every twenty shillings, of the remaining seventeen shillings
and sixpence the adventurers may have eight shillings, and account to the
tributor for the residue, which is nine shillings and sixpence. And thus it is
said 'Petherick Kernick of Hantergantick, Abednego Baraguanath of Towed-
nack, Dungie Crowgie of Carnalizzy, and Degory Tripeoney of Gumford,
have jointly taken a copper mine upon tribute of nine and sixpence in the
pound,' &c.
"It has always been the case in large mines to set several parts of them in
small portions of ground called pitches. A tribute-pitch consists of a few
fathoms in length on the course of the lode. Two pitches may meet half-way
between two shafts, and draw their ore to that shaft with which either of them
is connected. If a pitch is high up in the mine at a shallow level, it is
called a 'pitch upon the back;' but if lower down, in, or joining with the
bottoms, it is called a 'bottom pitch.' The time they contract for is generally
four months, and to work the pitch at all working times in a regular manner
with a certain number of men. The tributor is obliged to work one month,
or forfeit to the owner twenty shillings for every man he is obliged to employ:
in lieu thereof, if he does not choose to continue at the month's end, he
declines the occupation of his pitch, and forfeits to the adventurers all the
ore which shall be broken. A tribute-taker, as well as every other man in a
bal, obliges himself and partners to lend a hand gratis at the capstan when-
ever required, upon the penalty of two shillings and sixpence for each person
respectively who refuses his assistance. The takers of tribute-pitches in a
copper mine are likewise obliged to mix their ores with those of other pitches,
or with the owner's ores, and to sample the same according to the will and
discretion of the captains, else the parcels of ore would be very small where
there may be twenty pitches upon tribute in one mine. Before the parcels
are mixed together they take from each a fair, honest sample, and mark them
A, B, and so on. These are used as checks upon the whole assay.”
This question will be more fully treated of in the next section of this
volume. It will be instructive, however, to give the custom in Pryce's time.
In a mixed parcel of fifty tons, A may have twenty of £15 value per ton,
B may have twenty-five of £14 10s., and C may have five of £16 per ton,
according to the private samples, yet the gross fifty tons may sell for £15 5S.
per ton. Nevertheless, the amounts must be divided among the tributors
according to the selling price, subject to a regulation for the private samples;
that is, the excess or diminution, for what it sells, must be proportioned by
the produce of the private samples; for if fifty tons sell at £15 5s., the amount
is equal to £762 10s. Pursuant to the above private samples:-
£ s. d.
A's
B's
C's
25
5
20 tons at 15 O о
14 10
16
O
£ s. d.
300 0 0
362 10 O
80 0 0
The amount
•
742 10 9
which is 20 O o short by private samples.
This is called 20 increase by £762 10 o which it sold for.
CHAP. IV.]
DOLCOATH COPPER ORES ACCOUNT.
109
Now the method of proportioning this £20 increase is done by the Rule
of Three direct. Thus:
£ s. d.
f
s. d.
£
£ s. d.
If 742 10 O
If 742 10 6
If 742 10
20
20
300 0 0
362 10
B
20
80 0
ARC
А
8 I 7 increase.
9 15 4
""
2 3 0
""
£742 10 о add £20 0 0 Amount, £762 105.
Here it is evident that if the adventurers were to account to the
tributors at the private prices, they would deprive them of twenty pounds
of which they ought to have their respective proportions, it being the abso-
lute value for which the commodity was sold. Also, by mixing these three
parcels, they have altogether brought a better price by twenty pounds
than if they had been sold separately. We further illustrate this matter by
entry of an account of ores sold and proportioned to the lords, adventurers,
and tributors :-
Quantity.
tons. cwts. qrs.
21 ΙΟ 2
DOLCOATH COPPER ORES WEIGHED TO 24TH MARCH, 1777.
Lord's part, 1-7th. Adventurer's net part.
£ S. d.
184 5 9
Price
per ton.
£
To whom sold.
Amount.
£
S.
d.
IO
Cornish Copper Co.
•
215 0 0
£ s. d.
30 14 3
TRIBUTOR'S ACCOUNT OF THE ABOVE Ore.
Quantity.
tons. cwts. qrs.
Price.
£ s. d.
A IO ΙΟ 2
II O O
Amount.
£ s. d.
115 10
Increase.
Amount.
£ s. d.
£ S. d.
O
B II O
O
8 10 0
93 10 O
3 64
213 8
118 16 4
96 3 8
Tributor's
part.
5s. from 205.
Tributor's share.
£ s. d.
29 14 I
10S.
20s.
""
48 I 10
21 ΙΟ
2
Sold at £10 per ton, £215.
The lord's one-seventh
•
£30 14 3
The tributor's one-seventh
The adventurer's net part
215
77 15 4215
106 9 10
The following extract from the Dolcoath Cost-Book for October, 1783,
cannot but be of interest, as showing the actual payments received, just a
century since, by the managers and the men :-
Richard Trevithick
•
John Vivian
Charles Vivian
•
one month, 40s.
ditto
40s.
ditto 40s.
4~~~
£ s. d.
2 O
2
200
And three others at the same pay.
stems. spals.
doc.
James Vivian
one month, 42s.
I2S.
2d.
2 13 10
Robert Reed
ditto 42s.
•
35.
2d.
2 4 10
And two others.
Frs. Vivian
ditto
50s.
I
I
2d.
2 9 10
Four others at the same.
IO others at
2d.
9 others at
ditto
30s.
6s.
ེ།
6 others at
3 others at
33 others
•
ditto 35s.
IS.
ditto 28s.
75.
1 1 1
2d.
Ο ΙΟ
2d. I IO IO
2 2
2
4 10
ditto 28s., 265., &c.
The month's cost being
Ditto for last month
•
2d.
I 19 10
•
£1769 4
8
£1800 I 2
It has been suggested that probably the managers made a considerable
profit by supplying the mine with materials, and in the case of Trevithick
we know that he received extra pay for his engineering works.
The mines of Cornwall had become so deep that the appliances which had
been in use were no longer sufficient for the work they were required to do—
ΙΙΟ
[BOOK I.
HISTORICAL SKETCH.
water-wheels working pumps, the rag-and-chain pumps, and horse whims
drawing buckets of water to the surface, were no longer sufficient for the
purposes of the miner. The water flowed into their lower levels quicker
than any of their machines could withdraw it, consequently important mines
were abandoned, or they were threatened with suspension until some means
could be found to raise the water more rapidly than any machines then in
use could draw it.
It is a tradition that Captain Thomas Savery was the first to place a
steam-engine in a Cornish mine. It is said-I have not been able to learn
if the authority is reliable-that it was at a mine in Breage-Mr. J. Carne
suggests Wheal Vor-at which the experiment was tried. A short notice of
this engine and of its ingenious constructor is therefore required.
"At the request of some of your members at the weekly meeting, at
Gresham College, June 14, 1699, I had the honour to work a small model of
my engine before you, and you were pleased to approve of it." Such is the
introductory address to the Royal Society of a little book called "The Miner's
Friend; or, an Engine to raise water by fire, described, and the manner
of fixing it in mines; with an account of the several other uses it is applicable
unto, and an answer to the objections made against it. By Thomas Savery,
gentleman, inventor of the steam-engine. (Printed for S. Crouch, at the
corner of Pope's Head Alley, in Cornhill, 1702.) Reprinted in 1827.”
It is usually said that about 1702 Savery introduced his engine. This
date appears to have been adopted from the little book quoted above,
from which the foregoing quotation was made. I am, however, disposed to
think Savery did not introduce his engine into any mine until a year or two
later. That he had been in Cornwall, examining the methods employed for
drawing the mines, is evident from the following: "I have known in Corn-
wall a work with three lifts of about 18 feet each, lift and carry a 3 inch
bore, that cost forty-two shillings a day.
I dare undertake that my
engine shall raise you as much water for eightpence, as will cost you a
shilling to raise the like with your old engines in coal pits" (Miner's Friend).
Savery's boiler was of cast iron. He appears, from his own description,
to have used two boilers. He says: "The first thing is to fix the engine in
a good double furnace, so contrived that the flame of your fire may circulate
round and encompass your two boilers to the best advantage." A vacuum
was formed in a receiver by admitting steam to drive out the air, and then
condensing the steam by pouring cold water on the outer surface of the
receiver, which caused the water in the shaft to rise by the weight of
the atmosphere into the void in the receiver. A valve prevented its
return, while another valve opened a passage to the up-cast pipe from the
receiver towards the surface of the mine; a supply of steam again passed
from the boiler to the receiver, forcing the contained water upwards through
the pipes. All the principles of the modern steam-engine were involved in
this simple machine of Savery's.
Savery's engine, requiring to be fixed at the bottom of the shaft, or within
30 feet of the level of the water to be raised, never came into general use.
Newcomen, with his atmospheric engine, was treading close on the heels of
Savery.
CHAP. IV.]
STEAM-ENGINES INTRODUCED.
III
In 1705 Newcomen, of Dartmouth, invented the means of giving motion
to a beam by using a cylinder and piston, which was a great advance. The
steam pressure in his boiler was above the pressure of the air, and sufficient
to drive the air out of the cylinder and produce a vacuum. This was really
atmospheric engine," its power being the weight of the atmosphere
pressing on a piston moving in a cylinder from which the air had been
driven out.
an “
In 1712 an engine called by his name was erected at Griff, in Warwick-
shire, which raised a load equal to 10 lbs. or 11 lbs. on each square inch
of the piston. The first steam cylinder was 23 inches in diameter.
In 1720 he put up an engine at Ludgvan-lez, in Cornwall, with a cylinder
of 47 inches in diameter, working fifteen strokes a minute.
Many similar engines appear to have been erected by this self-taught
engineer, and his inventive genius was constantly introducing improvements.
In 1746 a Newcomen engine was put up at Pool mine, now North Wheal
Crofty, which is described by Dr. Borlase, who says: "The engine is
now well known to the learned; but as their books do not reach everywhere,
and this machine is especially serviceable for the working of deep mines,
and of great advantage to the public revenue, a general explanation, &c.,
is proper." For this explanation our readers are referred to the numerous
works which have been published on the steam-engine.
In 1756 several of those engines were at work. A dozen at least are
named. One of these was at the Herland mine, having a cylinder of
70 inches diameter. The objection to this engine was the cost of coal. To
lessen this, several methods were suggested for increasing the elasticity of
the steam and reducing the size of the boiler. Strange boilers of granite
were then in use, having some internal fireplace, which was probably a
system of copper tubes.
Richard Trevithick, senior, was in 1765 the manager of Dolcoath mine,
where at that time there were two atmospheric engines. The adventurers
purchased the "Old Carloose" engine, and the elder Trevithick was em-
ployed to re-erect it. We learn that "the greatest improvement, however,
was Trevithick's new semicircular boiler top, which, at a cost of £93 8s. 9d.,
took the place of the original flat top, weighted down by granite slabs.
Richard Trevithick, sen., removed the objectionable flat top; every part
was made circular, giving uniform and greater strength. The increased
pressure of steam in the stronger boiler, by only a pound or two on the inch,
materially increased the effective force of the engine. When re-erected, this
Carloose engine cost £2,040.
Trevithick senior's account-books, commencing in 1765, prove the use,
ten years before the erection of his engine, of two steam-engines in the Dol-
coath mine. The "Bullen Garden Fire Engine," and the "Litta Engine,"
and many others were then at work in other mines, for Borlase said, in 1746:
"There are several other very considerable mines now worked by the fire
engine in Cornwall. Huel-rith in Godolphin Hill, Herland, Bullan Garden,
Dolcoath, The Pool, Bosprowal, Huel-Rose, and some others." †
* "Natural History of Cornwall." 1758.
"The Life of Richard Trevithick, with an Account of his Inventions." By Francis Trevithick. 1872.
I12.
[BOOK I.
HISTORICAL SKETCH.
In 1770, Richard Trevithick, senior, obtained from Sir Francis Basset a
grant of the mine sett of Roskear, then commonly known as Wheal Chance,
upon which he appears to have erected an engine of his own construction.
Trevithick's account-books, commencing January, 1777, contain a list of
sixty-four Cornish copper mines then at work, most of those mines having
steam pumping-engines. We learn also the interesting fact that the Cornish
ticketings at that time indicate a yearly produce of copper ore of about
24,000 tons, valued at £156,000.
In the history of mechanical art, an eminent professor says two modes of
progress may be distinguished-the empirical and the scientific. Not the
practical and the theoretic, for that distinction is fallacious: all real progress
in mechanical art, whether theoretical or not, must be practical. Up to the
time of Smeaton all progress had to be empirical. In 1777 Watt erected his
first engine in Cornwall. He then met the Hornblowers, who came from
Staffordshire, and who had been erecting engines for fifty years; and Bonze,
who had five engines at work with cylinders of 60 to 70 inches diameter.
Watt's advance was directly the result of scientific inquiry. In 1763 and 1764
Watt was employed, under the direction of Professor Robison,* in repairing
a small model of Newcomen's engine which belonged to the University of
Glasgow. He detected various defects in that machine, and ascertained by
experiment the causes. From the first Watt went experimentally to work,
the results of his labours being shown in the specification of his patent in
1769. The expense of carrying out Watt's invention was at first defrayed
by Dr. John Roebuck, the original projector of the Carron Iron Works. On his
retirement from this enterprise Mr. Matthew Boulton, of Birmingham, joined
Watt, and furnished all that was necessary to render the genius of Watt
practically available. In 1775 Smeaton supplied the Chacewater mine with
an atmospheric engine. In 1776 the first Watt engine was built at Soho, and
in 1777 he went into Cornwall, and erected an engine at Wheal Busy, near
Chacewater, and another at Ting Tang, near Redruth. Hornblower and
Bonze, Watt tells us, had been actively supplying the mines with various
forms of the atmospheric engine. In 1782 Watt patented an expansive
engine, applicable to both double and single engines.
The following letter from James Watt to his partner will show the
condition of the Cornish mines at that time:-
"Chacewater Company sunk £50,000 and upwards in setting that mine
to work; and whether they have recovered it all yet seems uncertain,
although the mine has been tolerably prosperous.
"Wheal Virgin and Co. lost £28,000 in two months' unprosperous
working. Poldice has sunk a very great sum, and is not now gaining nor
saving. It has cost £35,000 to fit up, and drains Wheal Virgin in this
working, and it costs above £10,000 a year to draw the water after all that
can be done for them. Roskear mine has been long languishing, and does
not pay costs now. At Dolcoath mine it is said they use £500 of timber a
month, and a new kibble rope of above a ton weight is worn out in a fort-
night. It takes fully fifteen minutes to draw a kibble of ore there, which
weighs only about 3 cwt. It cost three years' work, and I believe as many
*"Narrative of Mr. Watt's Invention of the improved Engine." By Professor Robison. 1796.
CHAP. IV.]
WATT'S PUMPING ENGINES.
113
thousand pounds, to sink a new shaft in that mine, and every fathom of an
engine shaft that is sunk under the engine costs from £50 to £100.
"United mines have been at death's door, and are still in a tottering
state. Wheal Union adventurers, after working more than three years, were
glad to sit down with a loss of £7,000 or £8,000. If we had not furnished
them with more effectual means of drawing the water, I believe almost all the
deep mines had been abandoned before now."
The history of the introduction of Watt's engine into Cornwall cannot be
better told than by the following extracts from his own correspondence in
the volume now quoted :-
<
"On July 25, 1776, Mr. Boulton wrote to Mr. Watt, from Soho, that he
had an application for an engine from a distiller at Bristol, to raise 15,000
gallons of ale per hour 60 feet high; another for a coal mine in Wales;
another for a Mr. Langdale, of Holborn, a distiller; and another for a dis-
tiller at Mile End. The wheel-engine is ready for trial,' he writes, except
the steam-pipe; the boiler is set; and many wheels will be wanted so soon.
as they are ready for sale.' He says, 'If we had a hundred wheels ready
made, and a hundred small engines and twenty large ones executed, we
could readily dispose of them.' And on November 31, 1776, he sent to Watt
to tell him that he had had a positive order for an engine for Ting Tang
mine, in Cornwall; and from what he had heard from Mr. Glover, he thought
they might soon expect other orders from that mining county.
"In May, 1777, Mr. Watt wrote to Mr. Boulton that 'Wilkinson is going
to work in the forge way, and wants an engine to raise a stamp of 15 cwt.
thirty or forty times in a minute. I have set Webb to work to try it with
the little engine and a stamp hammer of 60 lbs. weight. Many of these
battering-rams will be wanted if they answer.'
"October 30th, 1777, Mr. Roebuck wrote from Bowness to Mr. Boulton
saying that he had great pleasure in hearing of the success of their engines
and that they had commissions from Cornwall. In 1778 Watt was in Corn-
wall, superintending the erection of engines there, and his success more than
equalled his expectations. He says, in writing to Dr. Black, ‘We have
succeeded in saving three-fourths of the fuel over the engines here, which
are the best of the old kind in the island. The large engine at Chacewater
mine, lately finished by us, is 63 inches diameter, has a 9-feet stroke, makes,
when going out of hand under its full load, eleven strokes per minute, works
a pump of 17 inches diameter and 53 fathoms deep, and moreover puts in
motion a very strong connection-rod, 25 fathoms long, before it comes to the
pump head; which rod, and the others which belong to three lifts of pumps,
weigh above 9 tons, the vis incrtie of which and its counterpoise demand a
very considerable power. This engine, when going at the above rate, burns
128 bushels of Welsh coal per twenty-four hours. We have agreed to take
£700 per annum for our part of the savings by this engine. The water of this
mine formerly baffled two engines—one a 66 and the other a 64; but though
this is the rainiest season, and the water the most plentiful below ground, we
keep it very well under hitherto. But that you may know what a job it was,
**
"The Origin and Progress of the Mechanical Inventions of James Watt," vol. ii. By James
Patrick Muirhead, Esq., M.A. 1854.
I
114
[BOOK I.
HISTORICAL SKETCH.
we were three months going at the above rate in "forking," or unwatering,
the mine. The whole county declared it impossible; some on account of
the known great quantity of water, and others from a belief that the engine
could not work the pump to that depth.' Watt, in the same letter, says that
the whole county now felt confidence in the engine, and he had received
orders for several others. Many abandoned mines were set to work again
with Watt's engines; and at that time there were five engines actually
working, and eight more in contemplation. At the same time they were
making an engine to send to France; but Watt says, 'No part can or will
pay us so well as Cornwall, and we have luckily come among them when
they were almost at their wits' end how to go deeper with their mines.'
"The 13th of January, 1779, Mr. Watt, writing from Birmingham to
Dr. Black, says that his anxiety about his engines has been very great, but
now his prospects are looking much brighter, and he thinks that another
campaign in Cornwall will do very great things.
<
“Dr. Black, on 15th March, 1780, asks Watt what he is doing at Wheal
Virgin mine in Cornwall, and Watt replies in a letter, dated the 25th October,
1780, that his prospects were brilliant. Our income increases yearly; will
have a considerable increase soon in Cornwall, and a much greater one
when Wheal Virgin mine sets to work. About a year hence they are to pay
£2,500 per annum, and Poldice, which will go on at the same time, £1,500.
My situation hitherto has been of the most uneasy sort, and I am So
habituated to disappointment, that even these splendid prospects cannot
raise my spirits to par.'
"In writing from Birmingham, October 31st, 1780, Watt says: 'You have
had occasion to know my sentiments from the beginning, and know that in
place of this Act, which is such a grievance to them (the Cornish adventurers),
I would willingly have taken £7,000 and made the invention free to all men ;
but neither Parliament nor anybody else would then give me that sum,
though, by-the-bye, I should not have put much of it in my pocket, yet I
should have been much richer than I am now.
It appears by our books
that Cornwall has hitherto eat up all the profits we have drawn from it, and
all we have got by other places, and a good sum of our own money into the
bargain.'
"July 26th, 1781, Watt went to Penryn, and swore that he had invented
"certain new methods of applying the vibrating or reciprocating motion of
steam or fire engines to produce a continued rotative or circular motion
round an axis or centre, and thereby to give motion to the wheels of mills or
other machines.' This affidavit he transmitted to Mr. Handley by post, with
directions to get it passed as quickly as possible. In 1782 Watt suffered
much from bad health, and he was greatly inclined to abandon Wheal Virgin
and Cornwall altogether, and devote himself to the rotative machines, only
he felt it would be dropping the substance to catch at the shadow. But the
engines in Cornwall gave him so much trouble that he wrote, 'Peace of
mind and delivery from Cornwall is my prayer.'"
About 1782 the Hornblowers caused Watt great uneasiness in Cornwall,
but it was stated that their engines were not equal to Watt's, and in 1783
Watt writes: “Affairs in Cornwall go on very prosperously. It is said
CHAP. IV.]
WATT AND THE TREVITHICKS.
115
Wheal Virgin will gain £3,000 per month, as it proves much richer than we
expected, and the costs much less; but it will be some time before we can
have any cash from it, or indeed get any considerable remittances from the
county, as money is exceedingly scarce there."
In 1783 a large number of miners in Cornwall were expending consider-
able sums of money in working and draining the mines; and, as already
stated, they were greatly indebted to the genius of Watt, for without the aid
of that engineer almost all the deep mines would have been abandoned. In
the same year all but one of the engines in Cornwall were altered, so were
many in other parts of England.
In 1797 Mr. Watt writes: "We have got a fresh crop of engine pirates.
Mr. Butt, our great opponent, has committed a great faux pas in Cornwall,
and we have been entreated to make his engine go on our own terms, at a
mine which had set us at defiance.”
On the 1st March, 1802, Mr. Watt writes to Mr. Hamilton from Heath-
field: "Our engine trade thrives. The profits per cent. are, however, very
moderate; it is by the great capital and expensive establishment of engi-
neers, &c., that we keep it up. Without our tools and men, very little could
be done, as we have many competitors, and some of them men of abilities."
This extract sufficiently proves that at this time the firm of Boulton and
Watt had overcome every difficulty. Their engines were draining all the
deep mines, thus enabling the miners to penetrate to greater depths.
The elder Trevithick for many years ran a very close race with James
Watt, and an unkindly feeling existed between them. The younger Tre-
vithick, who established for himself a name as an inventor second only to
that of Watt, was first employed in Stray Park mine in 1790, when he
received 30s. a month, his father, as manager, obtaining 40s. a month. In
1792 he was employed by the shareholders in Tin Croft mine to examine
into the duty of an engine by Watt, and of another by Hornblower. Early
in the younger Trevithick's career it appears that one of Watt's pumping
engines at Wheal Treasury worked badly, and at last stopped. The engine-
man in charge could do nothing with her, when young Trevithick offered his
services, and made things right; and the father was wont to boast "that the
best man in the mine could not do what his boy had done.”
At the end of the eighteenth century the pit-work usually consisted of
leathern buckets, with two or three pistons, such as were at that time in
general use; and Lean* tells us: "They were generally in a very bad state,
and it may be asserted that the engines were idle at least one-third of the
time, repairing the pit-work and changing buckets." And at this time
Trevithick introduced the plunger-pole instead of the common box and
piston, wherever he found it practicable to do so.
Trevithick after this became extensively employed in the mines of Derby-
shire and Durham. In 1798 Trevithick, by one of those moves common to
master minds, converted his plunger-pole into a prime mover, in positions
commanding a stream of water, through pipes from elevated ground. This
was first erected by him at Prince William Henry mine,† for giving motion to
* Lean's "Historical Statement of Steam Engines in Cornwall." Published in 1839.
+ Previously Wheal Chance-subsequently Roskear mine.
I 2
116
[BOOK I.
HISTORICAL SKETCH.
the pump-rods. This water-pressure engine continued to work satisfactorily
for seventeen years.
Considerable discussion has arisen as to the discoveries of Arthur Woolf,
and their application by Trevithick. In 1808, and not until then, Woolf was
a workman under Trevithick, who paid him £30 a year, and he received at
the same time 3 a week from Meux's brewery, London.
The further progress of engineering in connection with mining must be
considered in the next section.
COPPER.-GENERAL STATE OF THE COPPER MINES IN CORNWALL FOR SEVEN YEARS ENDING
31ST DECEMBER, 1798, DURING WHICH TIME BETWEEN 70 AND 80 COPPER MINES WERE WORKED.
Adventurers'
Amount of Ore.
Labour.
Materials.
Total Cost.
1792
£
S. d.
279,331 15 10
1793
283,853 12 11
1794 293,853 10 11
1795 305,320 6 9
1796 348,836 12 11
1797 320,606 15 9
1798 405,488 15 9
179,187 15
£ S. d. £ s. d.
150,824 12 3 91,361 6 4
176,333 2 7110,122 15 2
5 111,093 19 11
£ s. d.
251,865 19 11
294,226 15 O
294,775 19 5
189,713 10
III1,640 2 3
312,047 7 5
201,995 18
6 105,925 12 I
324,897 18 4
189,821 15
11 109,008 7 3
309,060 14 10
253,601 12 3 146,253 16 3
408,248 7 11
Profit.
£ S. d.
27,465 15 11
23,938 14 7
11,546 o II
£2,257,291 10 10 1,341,478 7 0785,405 19 32,195,123 2 10 62,950 II
Net Profit for Seven Years, £42,168 8s. od.
Loss.
£
S. d.
|
10,373
2 I
168
922 8 6
6,727 O
2,759 12 2
5 20,782 3 5
The columns of labour and materials added together do not make up the total cost, because the
accounts sent from some mines do not distinguish the amount of labour from materials; and therefore
could be no otherwise arranged than by being carried on at once to the column of total cost.
London, 17th June, 1785.
Messrs. Vivian and Boulton, on behalf of the Copper Mine Interest of Cornwall, and Mr. Williams,
for that of Anglesey, having met to consider of the best means of promoting their general and mutual
interest in the copper trade, are of opinion-
That the whole of the metal to be produced by their ores should be brought to one general sale, under
the direction of proper persons, and disposed of to the best advantage at one and the same price, according
to the proportions produced from each country.
That warehouses for that purpose should be established in London, Liverpool, Birmingham, and
Bristol, under the management of persons whose duty it shall be to consult and promote in every instance
the general interest of the united stocks and trade at large.
That to this great end it will be necessary for the Cornish miners to smelt all their own ores and bring
their metal into the markets, to meet the Anglesey metal, so that both stocks may assist each other and be
disposed of together as near as may be, whereby the losses heretofore sustained by competitions at market
may, in future, be effectually prevented, and the fair value of the commodity secured to the owners.
That when the Cornish miners have settled the establishments that may enable them to smelt their
ores, and bring the metal to market, a meeting of the principal persons interested in the mines, both of
Cornwall and Anglesey, be held for the purpose of settling all the preliminary rules and regulations of
such their united trade, by which rules and regulations both parties should be bound in the strongest ties
of law as well as honor.
And as it appears the mutual wish of the parties to promote this general proposition, we have every
reason to hope it may be brought to a speedy and happy issue.
Witness our hands,
JOHN VIVIAN.
MATTHEW BOULTON.
THOMAS WILLIAMS.
Mr. Williams will be happy to attend the gentlemen of Cornwall at any meeting they may choose to
fix, having notice of it in time for the journey from Anglesey to Cornwall.
The copper mines discovered in other parts of the kingdom, with the
exception of the mines of Anglesea and those of Staffordshire, have no
especial interest. They will therefore be treated briefly, since the most
important will receive close attention in that section which is devoted to
modern practical mining.
STAFFORDSHIRE AND DERBYSHIRE.-Farey, in his general view of the
CHAP. IV.]
THE ECTON COPPER MINE.
117
agriculture and the minerals of Derbyshire (1811), gives the following list of
copper mines in that county at the latter part of the eighteenth century:-
CUMBERLAND MINE.
NURSERY MINE
ALTOW WIN
BONSAL
HARTINGTON
HILL HOUSE RILETCH
MIXON MINES.
RIBDEN MINE.
WIRE MILL
DALE
•
•
Matlock Bath-produced only a few specimens.
Hopton. From this the specimens in the Woodwardian Collection, at
Cambridge, are supposed to have been derived.
Ashburne.
Copper ore in the vegetable soil.
"A large lump, which the late Thomas Woodhouse ploughed up on the
fourth Limestone Hills."
Upper Elkstone-produced a little copper.
•
Caldon.
Warslow.
Alveton.
Dr. Plat, in his history of Staffordshire, writes: "The copper ores of
this county must also be referred hither, not only as they are stones, but also
as they include much sulphur, whereof there has been dug divers sorts, out
of Ecton Hill, in the parish of
Witton, belonging to the Right
Honorable William, Earl of
Devon; there is of it, too, about
Beresford-near the most in-
genious Mr. Cottons-and at
Upper Elkston, and some think
at Madeley, both in the lands
of the worshipful John Offley,
Esq., but none were ever
thought worth digging but at
Ecton Hill, where the mine
was worked several years by
my Lord Devon himself, Sir
Richard Fleetwood, and some
Dutchmen, but they had all
left off before I came into the
county, as not worth their
while, copper coming cheaper
from Sweden than they could
make it here; so that the
workmen being dispersed, I
could learn little more con-
cerning it, but that the veins lay
from eight to fifty yards deep,
but all dipt north-easterly; that
they broke the rocks with gun-
powder, and got three sorts of
ore. A black sort, which was
the best; second, a yellow sort,
ENCINE
SHAFT
LIMESTONE
EASTGATE LEVEL
34 FM.
84
124 FM
135
154. FM
230 FMS FROM
SURFACE
So
SCALE
54 FM.
STRATA
THE
DUTCH MAN'S
LODE
100
FATHOM S
Fig. 12.-Section of Ecton Mine.
the worst; and, third, a mixed sort of both, which they smelted at Ellaston,
not far off, where they had mills," &c.* Farey, in his Derbyshire,† refers
also to this mine.
1686.
* "The Natural History of Staffordshire." By Robert Plat, LL.D.
+ "General View of the Agriculture and Minerals of Derbyshire." By John Farey, sen., Mineral
Surveyor. 1811.
118
[BOOK I.
HISTORICAL SKETCH.
"Near to this county (Derbyshire) is the famous Ecton mine, in Wadslow,
in Staffordshire, whence most immense quantities of copper ore have been
extracted before 1770. This ore was smelted at Denby, in Derbyshire, on
account of the coal there being supposed to be particularly proper for the
purpose, at which time works were first erected at Whiston, in Kingsley, in
Staffordshire, and much enlarged in 1780, for smelting and refining the Ecton
ore with coals from Hazle-cross, in Kingsley, the Duke of Devonshire, the
owner of Ecton mine, having purchased the Hazle-cross estate, &c., on
purpose, as I have been informed. . . . . The body of copper ore seems now
(1811) nearly or quite exhausted in Ecton mine, but the thick skirts to the
vein, and numerous scrins and small veins, or strings branching therefrom,
CLAYTON
DRAWING SHAFT
EAST PIPE
LIMESTONE
30 FM
46 FM
64 FM
95 FM
140
סון
124
WEST PIPE
ADIT LEVEL
STRATA
RIO FATHOMS FROM SURFACE
Fig. 13.-Section of Clayton.
which the miners neglected to follow when
the copper ore was in such plenty, still
produces considerable quantities of lead ore,
which is smelted at Ecton, and about ore
enough to produce a ton of copper weekly at
Whiston, where about 1781 twelve tons of
refined copper were produced weekly from
this mine."
"The Ecton copper mine,"* to quote
John Mawe, "is the only one of any conse-
quence in Derbyshire, to which, though on
the edge of Staffordshire, it is generally
reputed to belong. The general produce
of this mine is massive rich yellow copper
ore, frequently in contact with galena and
blende, but specimens occur of purple, steel
blue, brown, or brass yellow colours. The
ore yields from forty to sixty per cent., and
is sometimes vitreous and black. Some-
times, though rarely, it is crystallised in the
cube and its modifications.
"The calcareous spar of Ecton is a sin-
gular modification of the rhomb, very trans-
parent, sometimes of a rich topaz colour, and
generally containing brilliant crystallised
pyrites in the interior. Fluor, water-coloured,
or light blue, also appears finely crystallised with galena. By the decom-
position of the copper pyrites on the calcareous spar arises a beautiful
green efflorescence clothing the spar, and sometimes appearing to pass into
pearl spar.
Ecton also produces mountain blue and mountain green,
the former approaching to azure, the latter to a light verdigris colour.
The fracture of these substances is earthy and uneven.
They absorb
moisture, and appear to be composed of barytes-granulated calcareous
spar, and clay, with iron and green calx of copper. The famous vein
of copper ore called Ecton mine lies near Hartington, being what the
* "The Mineralogy of Derbyshire, with a Description of the most interesting Mines." By John
Mawe. 1802.
CHAP. IV.]
COPPER WORKS AT KESWICK.
119
Germans call a stock-work, and the only one in the kingdom. It is situated
from the surface to the bottom in a blackish-brown limestone, the strata of
which are in the greatest confusion, extremely irregular, and running in
all directions, as the reader may judge from the annexed plate.*
"This mine was probably worked at a very early period; it is one of the
deepest in Europe, and is now (1802) worked to the depth of 220 fathoms, or
1,320 feet; during the time it produced the greatest quantity of ore the profits
were immense. This work seems very different from the generality of veins;
it has the appearance of large cavities or openings in the stratum filled with
copper ores. There are some other mines in the neighbourhood, of little
consequence. This mine was extremely productive, and at one time employed
more than 1,000 people. The rich ore was in amazing large heaps, being in
some places 70 yards broad, in others not more than 10 yards. It was smelted
at Cheadle,† where coals are more plentiful, and the copper is greatly
esteemed and much in request for large boilers, &c., being more ductile
than any other." A similar formation was discovered and worked at
Clayton. It will be seen from the section given (Fig. 13) that the pipe vein
in Clayton had no such swelling out as was so remarkable in the Ecton
mine.
CUMBERLAND AND WESTMORELAND.-Considerable copper mines existed
near Caldbeck and Hesket Newmarket, in Borrowdale and in Newlands, in
the neighbourhood of Keswick. Here the famous mine of Goldscalp (Gold-
scope) is situated, from whence, by the old workings and other documents,
it appears that immense quantities of this mineral were formerly obtained.
"At Newlands, which stands among the mountains called Derwent-Fells,
and other places near it, some rich veins of copper, with a mixture of gold
and silver, were found in Mr. Camden's time by Thomas Thurland and
Daniel Hochstetter, a German of Augsburg, which had, indeed, been dis-
covered some ages before, as appears from the Close Rolls of King Henry III.
n. 18, but were not wrought. So far is it from being true, that Tully hath
said in his Epistles to Atticus, "'Tis well known that there is not a grain of
silver in Britain;' nor would Cæsar have said that the Britons make use of
imported copper, if he had known of the mines in this county, which afford
now a plenty, not only for use but exportation. Keswick, also, was a place
formerly noted for mines (as a certain charter given them by King
Edward IV. proves), and is still inhabited by miners, as is also one of the
isles in the lake adjoining by the same artificers from Germany." ‡
The following, from Robinson, gives an outline of the early history of
these mines:-
"In the beginning of Queen Elizabeth's reign there was erected a copper
work near the town of Keswick, the most famous at that time in England,
and perhaps in Europe. The operators, managers, and miners were most of
them Germans. The chief steward of the work was one Heckstetter, who,
by his books of account, which are most regular and exact, and all in large
imperial paper, as well as by other writings I found under his hand, appears
* Mawe gives a very rude plate.
+ William Hutchinson, F.A.S.,
The smelting operations appear
An actual section, to scale, is inserted, Fig. 12.
"History of Cumberland
History of Cumberland"; "Survey of England,” p. 56
to have been carried on at several places.
120
[BOOK I.
HISTORICAL SKETCH.
to have been a man of great learning as well as judgment in metals and
minerals.
"The copper ore which kept these large furnaces at constant work was,
for the most part, got in the veins upon Newland Mountains, the royalty
whereof did then belong to the Earl of Northumberland.
"I find that some small quantities of ore were got upon Caldbeck and
Cunnington (Coniston) Mountains, and brought to the great work at Keswick,
being a place most convenient both for water and coal, which they had from
Bolton Colliery.
"In our survey of the mountains of Newland we found eleven veins
opened and wrought by the Germans, all distinguished by names given
them—as Gowd-Scalp (now Gold-Scalp), Long-work, St. Thomas'-work, &c.
-of all which veins the richest was that they called Gowd-Scalp. We found
the vein wrought three yards wide, and twenty fathoms deep above the ground
level, which is driven in a hard rock a hundred fathoms, and only with
pickaxe, hammer, and wedge, the art of blasting with gunpowder being not
then discovered. For securing of this rich vein no cost of the best oak-wood
was spared; and for the recovering of the soles under level was placed a
water-gin, and water was brought to it in troughs of wood upon the tops
and sides of high mountains near half a mile from the vein.
"The ore at the top of the vein, which appeared by daylight, was
sulphurous, but in sinking deeper, the vein got more moisture, and the ore
improved in goodness.
"The ore got by the gin under level was so rich in silver, that Queen
Elizabeth sued for it, and recovered it from the Earl of Peircy for a royal
vein.
"Most of the most judicious miners and chymists in England were con-
cerned in the trial, either as of the jury or evidence. The verdict was given
for the Queen; and, as the German books give account, a hundred tun of ore
was entered upon by the Queen's agents. This rich vein, and several more
in the mountains of Newlands, are now laid open, and recovered by his Grace
the Duke of Somerset; and, likewise, smelting-houses, furnaces, and all
other conveniences, are made ready by his Grace for setting forward a great
work.”*
The following is from "Two Letters concerning several Copper Mines,'
bearing date 1684-
"What quantity of unwrought copper ore is left upon the place?
""
"To the first query I answer, that there is a heap of ore by Darwent, near
Keswick, and I suppose nobody lays claim to it; but it is not worth anything,
for being there so long, the weather has eaten out all the copper that was in
it.. All the ancient men that wrought at the smelting of it (copper ore)
being dead; but it may be, Mr. Hextecher's book will give some account of
it. That book is in Mr. Aglionby's custody at Carlisle.
"The third question is, What thickness and goodness the vein of copper
ore is reputed to be of? In answer to which I say, it is reputed that the
thickness of the vein at Gouldscope, in Newlands, was 6 feet; but for the
* Robinson's "An Essay towards a Natural History of Westmoreland and Cumberland." London :
1709.
CHAP. IV.]
THE TURF COPPER MINE IN WALES.
121
goodness it cannot be known without comparison of divers sorts, to see
which is best, and no comparison can be made in things unseen."
It appears that so long since as the reign of Queen Elizabeth mines were
opened and worked on Caldbeck Fells, though the ore was said to have been
carried to the great work at Keswick, to be melted. The proverb shows the
estimation in which these mines were held in the sixteenth century:—
Caldbeck Fells
Are worth all England else.
No works of any account have ever been continued either here or at New-
lands, although an Earl of Northumberland appears to have in a very spirited
manner made sundry trials.
About 1794, William Rowe, Esq., of Liverpool, is said to have discovered,
on the south side of the High Pike, a rich vein of lead ore, which, at about
three feet below the surface, runs for at least a mile in length, eighteen
inches thick, and even seems to increase. Smelting works were erected,
but the mines were soon after abandoned.
On October 3rd, 1794, a correspondent informed Wm. Hutchinson* "that
a large copper vein had been discovered upon the north side of Carrock Moun-
tain (trials had formerly been made in several places). It is five feet wide,
and the copper worth £30 to £40 per ton. It was supposed two workmen
got 80lb. one afternoon. The lessee was the above William Rowe." The
editor of the county history, however, says, "We have since heard that this
vein has not turned out so well as was expected."
WALES.-Sir Andrew C. Ramsay† thus describes the Turf copper mine.
"It was in this country, more than half a mile west of Dol-y-frwynog, that the
once famous Turf copper mine was situated in the heart of the talcose schist,
which almost everywhere contains much iron pyrites in small crystals, scattered
through the rock, together with specks of yellow sulphide of copper. Very
small veins of this ore also intersect the mass. A peat bog occupied the
greater part of the bottom of the valley. The turf was pared off the surface
and burnt in kilns, and being partly saturated with some compound of
copper, a large residue of valuable copper was left in the ashes. Many
thousand pounds' worth were thus extracted. The neighbouring hills were
afterwards burrowed in all directions in search of the great lode or bunch,
from whence the copper was supposed by sanguine adventurers to have been
carried in solution to the peat. It was never found, and probably does not
exist; the water, that percolated through the rocks and rose in springs,
having more probably carried the copper, in the form of a sulphate, from
those minute quantities of the sulphide that are more or less diffused through
the mass of the hill that overlooks the Turf Copper Mine, in the peat moss
of which the copper was diffusedly deposited.
A little copper pyrites has been occasionally worked in it (purple hard
grits), near Llyn Peris," near the Pass of Llanberis.
"There are four quartz lodes bearing a little copper in a mass of trap
that lies west of the road between the third milestone and Tan-y-groes.
*Author of "The History of the County of Cumberland.”
+ "The Geology of North Wales." By A. C. Ramsay, LL.D., F.R.S., &c. &c. ("Memoirs of the
Geological Survey of Great Britain." Second edition. 1881.)
122
[BOOK I.
HISTORICAL SKETCH.
Three near Tan-y-ralt, once known as the Turian lodes, ran north and
south; and the other, at Cae Mawr, strikes east and west. All of these, many
years ago, were worked for copper without much success. On the opposite
side of the Mawddach at Glasdir-leaf, there is a copper mine, which has been
opened since the Geological Map was made. It was tolerably successful,
and is still worked a little. A little gold is found with the copper in this
lode. There are also two quartz lodes bearing lead ore a little north-east of
Moel Ispri, and at least seven similar lodes yielding copper, on the hills
immediately north-west of the Barmouth road, between Llanelltyd and the
fourth milestone from Barmouth."
Originally the lodes of Vigra and Clogau, near Dolgelly, were worked at
intervals for about eighty years, for copper.
ANGLESEA.—The copper mines of Anglesea, viz. the Parys mine, and
the Mona mine, were discovered about the year 1768. The period of their
greatest produce was about 1784, when they (Parys) yielded about 3,000 tons
of fine copper. Mawe, in his "Mineralogy of Derbyshire," gives the following
account of a visit to Anglesea, at the latter end of the eighteenth century:-
"Being now arrived in the Island of Anglesea, I was anxious to see the
celebrated mine in the Mountain of Parys. The smelting works* first attracted
my attention, being superior to any I had seen, and containing twenty furnaces
in a very extensive building. The mine is on the top of a mountain, of blue,
or perhaps quartose shistus, or perhaps some might call it a quartose shistus
with serpentine, ranging from east to west, about 500 yards in length, while
the breadth is about 100 yards, and the depth nearly as much. The bottom
is very irregular, masses of rider, or vein stone interfering; while the richer
copper ore runs into holes and crevices, in strange and various directions.
The shistus lies in irregular strata, and is covered with a bed of gravelly
heterogeneous matter, full of chert.
Copper is got for about two shillings a ton, and is laid in heaps of five
or six hundred tons, in the sides of which ovens or fires are placed, and the
sulphur in the ore soon taking fire, it continues roasting for six or nine
months, and is then forwarded for smelting. The produce of the mine is
very poor, about seven and a half per cent. Patches appear of fine cubic
mundic. On examining this immense mine, it does not appear like a vein.
About 500 yards to the east, the Cornish Company have sunk a shaft of
forty fathoms, but have only found small particles and strings of ore. They
have also driven north and south, but have not met with any vein.
'The Parys mine is worked at considerable expense, and with the Mona
mine employs about 1,200 hands."
Mr. Thomas Williams states that the Anglesea mines produced, fourteen
or fifteen years ago—that is, about 1784-3,000 tons of copper a year.
SCOTLAND.-Copper has been taken from a vein in a bed of limestone.
in one of the Shetland Islands, where a steam-engine was erected, and the
produce for a time was not inconsiderable.
Near Gatehouse, in Flech, in Kirkcudbrightshire, at the private grounds
of Cally, copper ore has been worked. Captain Treweek, of the Mona mine,
visited Scotland, and formed a company for the purpose of working the
* Mona Smelting Works, Amlwch.
CHAP. IV.]
COPPER MINES IN SCOTLAND.
123
mine. The veins were not very regular in these first trials, being disordered
and split into branches.
Mr. Taylor visited the mine in August of 1820, and found it necessary to
commence an adit for the purpose of draining it. They had then shipped for
Swansea about forty tons of copper, estimated to be worth £15 a ton; and
then about thirty tons more had been raised.*
*
In a contract between the King and Cornelius de Vois, in 1567, mines
of copper and tin, as well as gold, silver, and lead, are granted to him.
In 1576 the duty on copper was fixed, in the contract with Paterson, "at
six stone out of every hundred, counting six score to the hundred; but it was
required that, should the King require copper for making artillery for his
own proper use, it was to be supplied one shilling per stone cheaper than
the market price in France or Flanders.” †
In 1683, a letter in favour of Joachim Gonell, a German, who had a gift of
a copper mine in the parish of Currie, near the Water of Leith, says, "Many
attempts for finding out and working of copper mines within this kingdom
having hitherto proved altogether ineffectual," it was desirable to give the
applicant the gift of the mine, that others might learn to work the mine
profitably.
Aithree, between Stirling and Dumblane, a copper mine "affords copper,
50 of ane, 100 of the ore, beside that of silver to the value of an £100
ster., and to the value of £200 ster. it affords of gold.
Curry Water, four miles of Edinburgh, in John Scott of Lamphoy's
ground, copper ore. “I have seen the copper made of it."
King's Park, Edinburgh, "Lapis Heematites is found."
Elphin, beside Allen, in the Laird of Hiltown's lands, there is copper.
Largo-law, in Fife, "Copper enough."
Borthwick Hill, betwixt Hawick and Banxome, there is copper on the
north-east side.
Cantyre.-" Copper ore is found in a hole there of the colour of gold,"
probably pyrites.
Copper is found at Elphin, near Allen, at Largo-law, in Fife, and north-
east of Borthwick Hill, betwixt Hawick and Banxome.
"Copper was found at Aithree (which lyeth between Stirling and Dum-
blane), "affords copper, 50 of ane, 100 of the ore, besides that of silver, to the
value of £100 sterling, to the value of £200 sterling it affords of gold.”
Three miles eastward of Aithree, amongst the Ochills, copper was found;
and four miles from Edinburgh, in John Scott of Lamphoy's ground. In
Catherall's ground, four miles from Edinburgh, lead ore was found. At
Braid's Craigs copper has been found.
THE IRISH MINES.-In the days of Sir John Pettus the Irish mines were
in a very uncertain state, as the following quotations will tend to show :-
As for those mines within the English Pale of Ireland, granted to the
Mines Royal Society by Queen Elizabeth: "The Irish do acknowledge
that the English Palc is all the Countie of Dublin, Kildare, Carlough,
*"Notice of a Copper Mine at Cally, in Kirkcudbrightshire." By John Taylor, Esq., F.G.S.
("Transactions of the Geological Society," Second Series, vol. i. p. 164.)
† Reg. Sec. con. 1575-77.
124
[BOOK I.
HISTORICAL SKETCH.
alias Caterlough, in the Province of Leinster, and all the Province of Meth
-as it is divided into three parts, viz. East Meth, West Meth, and Long-
ford; and this circuit is called the English Pale, because those territories
were always inhabited by the English."
"But when the Society shall think it useful to make a further enquirie
into the latitude of their grant from the Crown, they will find Leinster,
Ulster, and part of Munster also to be included; but in so much ground as
is confessed by the Irish to be within the Pale, and anciently appertaining
to the English, there are store of lead mines affording good quantitie of
silver, also copper mines and iron mines, and other metals and minerals
which may prove a reward to industrie, and to the further inquiries of the
Society" (Pettus).
The Mucruss copper-mine is situated near the head of the great lake, by
which, and the river Laune, a complete water communication was opened to
the sea at Castlemain. A curious fact in the history of this mine deserves
attention. There was found in great profusion a mineral of a granulated
metallic appearance, between 1749 and 1754, as hard as stone, its colour on
the surface dark blue, tending to a beautiful pink. It was not copper ore;
it was thrown away as rubbish; nobody knew what it was except one
workman, who recognised it to be cobalt ore (arseniuret of cobalt). This
man managed to get away upwards of twenty tons of it as waste. Long
afterwards a more candid miner, who visited the works and saw some
specimens of it, told the proprietor of its value; but the deposit of it had
been worked out in order to explore for copper, and it only remained for
the mine-owner to ruminate on the fortune he might have made, if he had
possessed a proper knowledge of his business.
The quantity of copper ore raised whilst this mine was at work averaged
200 tons a month. It was, however, very rich-the poorest ore sold for £14
per ton, and the richest for £40. The total value of the ore raised in four
years, and sold at Swansea, was £80,000.*
* "The Industrial Resources of Ireland." By Robert Kane, M.D. Second edition. 1845.
CHAPTER V.
MINING FOR LEAD, SILVER, ETC., TO THE END OF. THE 18TH CENTURY.
BEFORE we proceed to the consideration of lead mines and those producing
gold and silver, it is desirable to allude to the MINES ROYAL already referred
to.* The Mines Royal Company appear to have established themselves as
smelters on the banks of the river Neath, and probably by their influence
mining operations were for a time extended; but by their exacting laws
they ultimately repressed the disposition to search for minerals.
Sir John Pettus, who had been then some twenty years a governor,
writing in 1670, thus defines a Mines Royal :—†
"Where the oar which is digged from any mine doth not yield, according
to the Rules of Art, so much Gold or Silver as that the value thereof doth
exceed the charge of Refining and loss of the baser Metal wherein it is con-
tained, or from whence it is extracted, then it is called poor Oar, or a poor
Mine.
"On the contrary, where the oar digged from any Mine doth yield,
according to the rules of art, so much Gold or Silver as that the value thereof
exceed the charges of Refining, and loss of the baser Metal in which it is
contained, and from whence it is extracted, then it is called rich Oar, or a
Mine Royal; this appertaining to the King by his Prerogative. And herein
consists the skill and honestie of the refiner, for some have made very good
products from that very Oar from which less skilful essayers could extract
nothing."
Among the "Remembrances of the Exchequer," we find a grant from the
King to John Sugg and Henry of Wisbich. "Whereas we are informed that
certain mines of lead, mixt with gold and lead oar, are found in the countie
of Salop," the King wills that the Barons of the Exchequer and Treasurer
may be certified of the manner of finding the said mines, and whether
any hath been transported, and by whom, &c. &c.-30th October, Anno 7.
1619.
In 1683, Sir J. Pettus translated and published the "Assays of Lazarus
Erckern," chief prover or assay-master of the empire of Germany, from which
we glean many important particulars and dates.
After naming twenty-three English counties and twelve counties in Wales
in which the "Mines Royal Society" and the "Mineral and Battery Works
Society" held various mines, he continues :—
"We have government of them all both in England and Wales, and part
* See Queen Elizabeth's Letters Patent, p. 93.
† Sir John Pettus's "Fodinæ Regales."
126
[BOOK I.
HISTORICAL SKETCH.
!
of Ireland (except the lead mines of Donegany)—in Derbyshire, and at
Mendyp, in Somersetshire. Of copper, Keswick copper mine, in Cumber-
land, which caused a great suit between Queen Elizabeth and the Earl of
Northumberland
and still have the care over it; but, for want of fuel
•
and skilful miners, it is of no use at present."
"To work for gold, the Mines Royal Society granted two leases on mines,
one at Pullox Hill, in Bedfordshire, the other at Little Taunton, in Glouces-
tershire, but they were not eventually successful."
"Of silver we have none but intermixed with other metals, especially
lead."
"We have mountains of Lapis calaminaris, especially in Gloucestershire,
Somersetshire, and Nottinghamshire, but we let the calamine go for ballast
into foreign parts in great quantity. I remember, about thirty years ago,
that one Demetrius, a German, did set up a brass work in Surry."
Carew, in his "Survey of Cornwall," quotes Sir J. Pettus on calamine,
and then states, as on his own authority, that calamine has been found in
the lead work by the Swanpool, in the parish of Budnich.
Of the Antiquitie of the Mines Royal," Sir J. Pettus writes:—
"These works in Wales, and some other in Devonshire, Somersetshire,
and Cornwall, as far as tradition can assure us, were anciently wrought by
the Romans. By the Damonii, in Devonshire and Cornwall; by the Belga,
in Somersetshire; and by the Dimete, in Cardiganshire. And Cæsar, in his
Commentaries, saith, that one reason of his invading the Britons was
because they assisted the Gauls with their treasures, with which their
countrie did abound. And Cimboline, Prince of the Trinobantes (wherein
Essex is included), who had lived much at Rome in Augustus his time, was
seated at Walden, in that countie, and did (according to the Roman way)
coin monie instead of rings, which might be from that mine which was after-
wards discovered by Henry IV. his time in that countie (as yet unknown to
the Society). However, 'tis certain there were mines which did supply former
ages, and may be again used with great advantage to this present age"
(Fodina Regales, p. 11, 1670).
THE SOCIETY OF MINERAL AND BATTERY WORKS.-"The Queen did
also, in the seventh year of her reign, grant to William Humphreys and
Christopher Shute, a German, all mines, minerals, and subterranean treasures
(except copperice and allom) which should be found in all other parts of
England (not mentioned in the former patent), or within the English pale in
Ireland, by the name of gold, silver, copper, tin, lead, quicksilver, cadmium,
oar, or Lapis calaminaris, and all manner of ewres, or oars, simple or pure,
mixt or compounded, for latten, wire, or steel, &c.
"And also on the same 28th of May, in the tenth year of her reign, the
Queen frames the participants into a corporation, by the name of The Society
for the Minerals and Battery Works.
"This was also look'd upon as so considerable a matter to the Crown
that Sir Nicholas Bacon, then Lord Keeper; the Duke of Norfolk; William,
Earl of Pembroke; Robert, Earl of Leicester; William, Lord Cobham; Sir
William Cecil, Sir Walter Mildmay, Sir Henry Sydney, Sir Francis Jepson,
Sir William Garrard, with twenty-nine more considerable persons-gentle-
CHAP. V.]
THE SOCIETY FOR MINES ROYAL.
127
men, lawyers, citizens, and foreigners-were participants. And this society
consisted of 36 shares, subordinate also into half and quarter parts, so that
it was capable of 144 shares. And this also by a joynt stock did effect
great things, which turned to good advantage both to the King and to the
Society."
MINES ROYAL.-About the third year of Queen Elizabeth, she, by
the advice of her Council, sent over for some Germans experienced in
mining, and being supplied, she, the 10th of October, in the sixth year of
her reign, grants the mines of eight counties, besides those in Wales, to
Houghsetter, a German, whose name and family still continue in Cardigan-
shire, and doubtless we had much of our knowledge from their predecessors,
who revived the work in Cardiganshire. They also entered upon another
work of copper at Keswick, in Cumberland, being within the royalties of the
Earl of Northumberland, formerly granted to him from the Crown, together
with all mines, &c. Whereupon the Earl opposed Houghsetter, but the
matter being brought to trial between the Queen and the Earl, it was the
opinion of the judges that, notwithstanding his frank, the Queen had power
to search for treasure in anyone's ground. . . . To prevent a return of similar
disputes, on May 28th, in the tenth year of her reign, the Queen erects a
corporation, of which William, Earl of Pembroke, was the first Governour,
and Robert, Earl of Leicester, James, Lord Monjoy, Sir William Cecill,
Assistants, and many other persons of qualitie joined, consisting in all of
twenty-four persons and as many shares, and those shares subdividable into
half and quarter parts, so that they might consist of ninety-six persons, their
votes being according to the proportions they had of shares. And this
society was and is entituled The Society for the Mines Royal, and they
have the grant and care of gold, silver, copper, &c., within eight English
counties and all Wales. These counties were Yorkshire, Lancashire, Cum-
berland, Westmoreland, Cornwall, Devon, Gloucestershire, Worcestershire, and in
Wales. As the question is constantly arising, we give the definition, On
Royal Mines, from Bainbridge.*
of
*
“According to the law of England, the only mines which are termed
Royal, and which are the exclusive property of the Crown, are mines of silver
and gold.† And this property is so peculiarly a branch of the royal pre-
rogative, that it has been said, that though the King grants lands in which
mines are, and all mines in them, yet Royal Mines will not pass by so
general a description. This prerogative is stated to have originated in the
King's right of coinage, in order to supply him with materials. In 1640 the
opinion of fifteen legal counsel was taken on the subject of Royal Mines,
and in 1670 their opinion was generally adopted, as stated by Sir John
Pettus, who gives the Rule by which a Royal Mine may be determined.
"The way of computing this by the art of cxtraction :—
£ s. d.
Two tun and a quarter of oar make a tun of metal at a medium rate, £3 10s.
which is
7 17 6
Carriage to mills at 6s. 8d. per tun
Sieves, tubs, and oar bags at 2s. is
•
0 15 0
0 4 0
So that the charge of the oar deducted at the mills which makes a tun metal costs
"A Practical Treatise on the Law of Mines and Minerals." By William Bainbridge, Esq. 1841.
Plowden, 336.
† 2 Inst. 577.
8 17 6
128
[BOOK I.
HISTORICAL SKETCH.
CHARGE OF SMELTING PER TUN.
2 doz. white coal, at 8s. per doz.
5 barrels of black coal at 2s. per barrel
Smelting wages, per tun
Stamping and washing slags, per tun
Smith's work, per tun.
Rents and repairs of the mills, carpenter's work, carriage to the water's side,
clerk's attendance at the mills, and incident charges, .per tun
CHARGE OF REFINING PER TUN.
£ s. d.
O 16 o
Ο ΙΟ 0
O 15
O 5
404
0 2 4
I 15 O
12 Ο ΙΟ
300 of lead wasted in refining and reducing, at 125. per cent.
Refiner's wages, per tun
•
Black coal, charcoal, bone ashes, carpenter's wages and smith's work, and other
incident charges
•
I 16 O
0 5 0
I IO O
3 II 0
16 II 10
Total charges
If the said tun of metal be made either of Goginian, Coomervin, or the Darrein
oar, the same yields in silver per tun of metal
One tun of lead, the waste being deducted, as aforesaid, is .
14 O о
•
12 O O
1
26 0 0
The charge in all is
Deducted out of £26 the clear profit of a tun of lead is
16 II 10
986
If the said tun of metal be made of the oar Coomsumblock, it yields £20 per ton in silver.
"This is to only show the manner of computing a Mine Royal by art;
but some are of opinion that all metals do contain gold or silver in them,
and that therefore all veins of metal do belong to the King".(Fodina Regales).
DEVONSHIRE AND SOMERSET.-Silver mines have been worked at Beer
Ferrers (or Beerferris, as it is sometimes called), a manor in the south-west
of Devonshire, of which the borough of Beer Alston (which returned two
members to Parliament) is held in Beergage tenure.*
The mines at Beer Ferrers and Beer Alston (says Lysons) are remark-
able for the length of time for which at different periods they have been.
worked, and for the quantity of silver which they contain, the silver in each
ton being from 802 to 120 ozs. Polwhele, in his "Devonshire," says "that
those mines which have usually been called the silver mines of Devonshire,
were no other than lead mines rich with this metal, is very evident. This
appears from the inscription on the silver cup presented by Queen Elizabeth
to the Earl of Bath.
وو
Lysons, in his "Magna Britannia," says: "The lead mines of this county
and Cornwall are more enriched with silver than those of any other part of
the kingdom. The produce of the mines at Combe Martin and Beer Alston
is said to have been unusually great in the reigns of Edward I. and II., and
to have much enriched the treasury of those monarchs. The Combe
Martin mines were reopened in the time of Queen Elizabeth, under the
* Risdon's "Survey of Devon."
CHAP, V.]
COMBE MARTIN LEAD MINE.
129
direction of Sir Bevis Bulmer, a skilful engineer, much esteemed by that
Queen and her ministers. Mr. Bushell, a celebrated mineralogist of that
day, and a pupil of Sir Francis Bacon, strongly recommended the reworking
of the Combe Martin mines to the Long Parliament in 1659.
In the first year (1488) of Henry VII. King of England, &c. &c.,
Mr. Bulmer saith: "The artists and workmen made (1485) humble suit
that the mynes, mineralle, and mineral stones already by them discovered
within the county of Devonshire, in England, might be supplied: for the
tynners of Cornwall and Devonshire had found a part thereof which
was rich, holding good store of silver, as they sought only for tynn, the
shodds whereof was very brittle, and of colour like unto lead, and were found
in the superfices of the earth, and contained in it by assay much silver. And
the said shodds have bin found in combs and vallies neare to the river side,
and not in solid places, the one place called Comb Martyn, the other Beere-
ferris, both in Devonshire, for so it is recorded in an ould parchment booke
at Mr. Somerster's house at Beerferris, in Devonshire. He was Archdeacon
of Cornwall and parson of Beere," &c. Money appears to have been collected
at fairs and by collections in the churches "towards the discovery of his
Majesty's silver mines."
"At Comb Martyn there was a fayre storehouse builded for that purpose,
&c. One thousand men were employed there and at Beereferris. Imple-
ments and tools, with other necessaries and extraordinaries, were as charge-
able as wages, as is recorded in that old ancient booke, &c. And those two
silver mines yielded yearly into his Majesty's treasury £44,000 sterling in
bullion and in leade, which lead was sold at £4 sterling the ton weight
thereof. In the year of our Lord God 1587, at Comb Martyn, in Devonshire,
was discovered a new silver myne by one Adrian Gilbert, gent., and John
Popler, of London, a lapidary. The which, when they found it to be stub-
borne to melt, and could not then master it and wyn that in the great which
the small assay proffered, there went a great fame thereof throughout Eng-
land. Mr. Bulmer, being then a great lead-man uppon Mendipp, in Somer-
setshire, having intelligence thereof, had by fortune a small quantity thereof,
viz. two pounds weight, brought unto him, and the gentleman which brought
it said, 'Sir, if you please, you may have a sufficient part therein,' &c. Mr.
Bulmer went to Comb Martyn, 'found great store of ewer,' and bargained
with Gilbert and Popler for one-half of the whole mine. For the space of
two years those silver mines yielded to each partner ten thousand pounds
sterling. The mines continued 'reasonable good' four years together, the
last two years not yielding so much by farr as the first two years; when they
were at the deepe, the said mynnes yielded £1,000 per annum.
And it was
called Fayes Mine, and it was wrought full 32 faddomes deepe, and 32
faddomes in length. In the hinder end of Comb Martyn's work Mr. Bulmer
gave away the last cake of silver which was made out of the myne. I did
both melt the leade thereof, and refined the same cake of silver, which forth-
with was sent up to London and there made into a cup and cover; and Mr.
Bulmer gave it gratis unto the City of London, and to remain from yeare to
yeare yearly for ever, unto the Right Honourable the Lord Maior of London;
and one Mr. Medly, a goldsmith in Foster Lane, made the same, with
K
130
[BOOK I.
HISTORICAL SKETCH.
Mr. Bulmer's picture thereupon engraved, and with these verses following
annexed:
When waterworks at Brokenwharf
At first erected were,
And Bevis Bulmer, by his art,
The water 'gan to rear,
Dispersed, I in earth did lie,
From all beginning ould,
In place called Combe, where Martyn longe
Had had me in his moulde.
I did no service on the earth,
For no man sett me free,
Till Bulmer, by his arte and skill,
Did frame me thus to be." *
In 1784 and 1785 the silver produce of these mines amounted to 6,500 ozş.
The Combe Martin and Beer Alston mines have long been celebrated
for their argentiferous lead ores. It is stated that the produce of these
mines was unusually great in the reigns of Edward I. and Edward II.
In 1293, William de Wymundham accounted at the Treasury for 270 lbs. of
silver raised in Devon. In 1294 it amounted to £521 10s. weight, and in
1295 to £704 3s. Id. weight. In 1296 great profit is stated to have been
derived from the Devon mines, and 360 miners were impressed out of Derby-
shire and Wales to work in them. In 1360 a writ was issued, authorising
certain persons to take up as many miners and workmen as should be neces-
sary to work in the King's mines in Devon, allowing them reasonable wages,
according to the custom of the country; to arrest and imprison such as
should resist, till they should give security to serve the King in the said
mines; and to buy and provide timber at a competent price.
Henry, Bishop of Winchester and Cardinal of England, and one of the
executors of John, Duke of Bedford, who had a grant from the King of the
gold and silver mines of Devon and Cornwall, rendered 26 lbs. and 2 ozs.
weight of pure silver as the fifteenth part of the pure silver raised in those
counties from 15th December, 21st to 16th August, 23rd of the same King's
reign.
In 1813 they were again opened, and worked for four years, producing
only 208 tons of ore in that time. In 1837 they were again worked, and we
had an opportunity of observing that the previous mining operations pre-
sented every appearance of having formerly been very unskilfully managed.
The two lodes near Beer Alston have produced large quantities of argen-
tiferous galena, often containing from 80 to 120 ozs. of silver per ton of lead.
According to Mr. Hitchings, the greatest quantity which occurred in that
part of them named South Hooe mine was 140 ozs. of silver per ton.
From Wheal Betsy, near Tavistock, which was reopened in 1806, from
300 to 400 tons of lead, and from 4,000 to 5,000 ozs. of silver, were annually
obtained. The produce of this mine had been previously greatly reduced.
In 1876 a little lead ore was raised, and in 1877 the mine was closed.
Borlase mentions, in 1758, that lead mines had anciently and lately been
worked in Cornwall, and that those most noted formerly were Penrose, Pen-
werty, Trevascus, and Guarnek (Garras). He states that the Penrose mines
(near Helston) had been wrought for about two hundred years-that is, from
about the middle of the sixteenth century, and that they had yielded tolerable
profit within thirty years. The only lead mine worthy of note at work in
* The "Discoverie and Historie of the Gold Mines in Scotland." By Stephen Atkinson. Written
in the year MDCXIX. Atkinson was a native of London, a refiner of gold and silver, was a "finer" in
the Tower of London about 1586, and afterwards engaged in refining silver in Devonshire from lead
brought from Ireland.
CHAP. V.]
LEAD AND ZINC MINING.
MINING.
131
Borlase's time was at St. Issy, near Padstow. Pryce describes the lead ore of
Garras, near Truro, to have been so argentiferous, that when wrought, about
1720, it produced 100 ozs. of silver in the ton of lead. (This mine was reopened
in 1814, and continued two years in work; during that time it produced
800 tons of argentiferous lead ore, containing 13 parts in 20 of lead, the lead
yielding 70 ozs. of silver per ton.) Wheal Pool, near Helston, about 1790
gave from 40 to 50 ozs. of silver per ton of lead, and works were erected for
extracting the silver. The lead ore of Wheal Rose, in the same district,
contained 60 ozs. of silver per ton. The lead mines which have been worked
around Chiverton and in Perranzabula belong to a later period, as do also the
lead mines in Menheniot and in the neighbourhood of the Tamar and the Tavy.
LEAD AND ZINC.-Over that portion of the Mendip Hills occupied by
the Mountain Limestone and Dolomitic conglomerate, lead and zinc mining
has been long carried on. The principal points were Tar Valley, near
Churton-Mendip, Priddy, Charterhouse, Shipham, Rowborough, Winscombe,
Bleadon, Worle Hill, and Bream Down. In the neighbourhood of Wrington,
on Broadfield Down, both lead and zinc have been found in the Dolomitic
conglomerate. It appears that the lead ores occur most abundantly in the
Mountain Limestone; zinc ores-especially calamine-in the Dolomitic con-
glomerate. Messrs. Buckland and Conybeare express their opinion that the
metalliferous deposits of the conglomerate were derived mechanically from the
débris of lodes which traversed the Mountain Limestone. They state that
much of the calamine has been formed stalactitically around dogtooth spar,
and that it is now found in the shape of hollow-cast and pseudomorphic
crystals, the calcareous matter having perished. It appears that both ores
are often found in veins, but at times they occur in beds, or are disseminated
through the strata. In the Mountain Limestone the ores occur almost invari-
ably in veins, but in the conglomerate they are frequently disseminated,
though occasionally found in fissure veins. Buckland and Conybeare also
remark that the veins are very thin, and that the gangue is calcareous spar,
occasionally mixed with heavy spar (barytes). Mr. Weaver says the veins in
the Dolomitic conglomerate run in all directions; that they vary from 1 inch
to 3 feet in thickness; and that their hades, or inclination, are very variable.
He enumerates galena, calamine, ironstone, manganese, calcareous spar,
quartz, barytes, and ochre as the minerals found in this region.
I
The calamine generally occurs in small particles, mixed with a gritty
earth; but at Wrington, according to Mr. Pooley, a mass was discovered
about ten tons in weight. In the parish of Binegar, we are told by Mr.
Billingsly, a great deal of calamine was at one time discovered. It was of
very good quality, and if the miners had not been stopped by the influx of
water, much calamine might have been obtained. A large quantity was also
raised at Mills, which was of an excellent quality. It was found in large
masses, lying horizontally in the Limestone, at about four or five feet from
the surface.
"An account of lead mines producing calamine, &c., at Durdham Down,
near Bristol, in the County of Gloucester; with a proposal for the disposing
of a small part thereof," is curious.
“A lease was granted for twenty-one years from 1712 of 2,000 acres of
K 2
132
[BOOK I.
HISTORICAL SKETCH.
the said ground to digg, trench, sink and mine in and upon the whole or any
part of the same, for the having, taking up, and carrying away of iron ore,
lead ore, magganess (manganese), and calamie
upon paying one
shilling out of every ton of iron ore (allowing two-and-twenty hundred to
each ton), two shillings for every twenty shillings' worth of lead ore, four
shillings for every twenty shillings' worth of magganess, and two shillings
out of every twenty shillings' worth of calamie when they are sold and
disposed of."
Several pits appear to have been sunk, and it is stated that "there are
many £1,000 worth of oar in view;" and "the small veins already discovered
are above 600, and which are found to run a tract of near a mile long," con-
taining "the calamie, of which may be got up many thousand tons.”
Much discussion has arisen over the question whether this metal, ZINC, was
known to the ancients. Beckmann insists upon it that Aristotle and Strabo
were acquainted with the ore of Luna Calamine. He contends that the
Cadmia named by them-which was found in Cyprus, and used for the
manufacture of brass-was the ore, calamine. The probability appears to be
that cadmium, furnace-calamine, philosopher's wool, Luna philosophica
Pompholyx (so called by Dioscorides), was known to the ancients as an Earth,
the metal zinc being the discovery of a later day, its name occurring first in
the works of Paracelsus, who died in 1541. Even then it is mentioned as a
rare thing, possessing wonderful properties.
Bergmann, in his history of the discovery of the method of extracting
zinc from calamine, wholly omits the mention of Dr. Isaac Lawson, of whom
Pott, in his essay on zinc, speaks very respectfully, acquainting us that he
really obtained some grains of that semi-metal from calamine. So that,
though Henckel was the first, Lawson was probably the second person in
Europe who procured metallic zinc from calamine. Whether he was the
Englishman who, according to Bergmann, went to China to discover the
method of doing it, is what I have not been able to learn with certainty.
Our English writers who have touched on this subject speak in high terms
of Lawson-I suppose from their personal knowledge of him-for they do
not refer to any written account.*
Thus Dr. Pryce says:† "The late Dr. I. Lawson, observing that the
flowers of Lapis calaminaris were the same as those of zinc, and that its
effects on copper were also the same with that semi-metal, never remitted
his endeavours till he found the method of separating the pure zinc from that
ore." And Dr. Campbell, in his "Survey of Britain,” is still more particular.‡
"The credit if not the value of calamine is very much raised since an
ingenious countryman of ours discovered that it was the true mine of zinc.
This countryman was Dr. I. Lawson, who died before he had made any
advantage of his discovery." The authors of the "Supplement to Chambers's
a
* Pott gives several quotations from a dissertation by Dr. I. Lawson, "De Nihil," which I have
never met with, and amongst others the following one: Quamois tapis calaminaris nec sublimatione, nec
cum fluxu nigro det zincum tamen similes flores, similis in igne color, similis tinctura cupri, et augmentum
ponderis probabilissimum, præbent argumentum lapidem calaminarem esse mineram zinci.”—Pott, “De
Zinco."
+"Mineral. Cornubiensis," p. 45.
"Polit. Surv. of Brit.," vol. ii. p. 35.
CHAP. V.]
CALAMINE SMELTED AT BRISTOL.
133
Dictionary,”* published in 1753, expressly affirms that "Dr. Lawson was the
first person who showed that calamine contained zinc. We have now on foot
at home, a work established by the discoverer of this ore, which will probably
make it very unnecessary to bring any zinc into England." To all this I
shall only add one testimony more, from which it may appear that the
English knew how to extract zinc from calamine before Mr. Van Swab
taught the Swedes the method of doing it; though this gentleman, unless I
have been misinformed, instructed the late Mr. Champion, of Bristol, either
in the use of black-jack for the same purpose as calamine, or taught
him some improvements in the method of obtaining zinc from its ores. The
testimony occurs in a dissertation of Henckel's on zinc, published in 1737.
He is there speaking of the great hopes which some persons had entertained
of the possibility of obtaining zinc from calamine-hopes, he says, which
had been realised in England: "Ce qu'un Anglais arrivé depuis peu de Bristol
dit avoir vu réussir dans son pays."+
The manufactory, however, of zinc was not established at Bristol until
about the year 1743, when Mr. Champion obtained a patent for the making
it.
About two hundred tons of zinc are annually made at the place where
the manufactory was first set up; and about seven years ago zinc began to
be made at Henham, near Bristol, by James Emerson, who had been many
years manager of that branch under Mr. Champion, and his successor in the
business.
"Near twenty years ago I saw the operation of procuring zinc from cala-
mine performed at Mr. Champion's copper works near Bristol. It was then a
great secret, and though it be now better known, yet I am not certain
whether there are any works of the kind yet established in any other part of
either England or Europe, except that before mentioned at Henham. In a
circular kind of oven, like a glasshouse furnace, there were placed six pots
of about four feet each in height, much resembling large oil-jars in shape.
Into the bottom of each pot was inserted an iron tube, which passed through
the floor of the furnace into a vessel of water. The pots were filled with a
mixture of calamine, or black-jack, and charcoal, and the mouth of each was
then close stopped with clay. The fire being properly applied, the metallic
vapour of the calamine issued through the iron tube, there being no other
place through which it could escape, and, the air being excluded, it did not
take fire, but was condensed in small particles in the water, and being re-
melted, was formed into ingots and sent to Birmingham under the name of
zinc or spelter."‡
“Queen Elizabeth in 1565 granted by patent all the calamine in England
and within the English pale in Ireland to William Humphrey, her pay-
master, and one Christopher Shutz, a German, and, as the patent sets
forth, a workman of great cunning, knowledge, and experience, as well in
the finding of calamine as in the proper use of it for the composition of the
* Art. Calamine and Zinc.
†This observation was first published in the fourth volume of the "Acta Physico-Medica Acad. Nat.
Cur.," 1737, but I have made the quotation from the edition of Henckel's works published at Paris, 1760,
vol. ii. p. 414.
Chemical Essays," vol. iv. pp. 33-40. By R. Watson, D.D., F.R.S. 1786.
134
[BOOK I.
HISTORICAL SKETCH.
mixt metal called latten or brass."* Dr. Watson appears to think that the
Mineral and Battery works established in 1568 were materially concerned in
the metallurgy of zinc. Moses Stringer, already quoted, says that mines of
latten, whatever, at that period, may have been meant by that word, are
mentioned in the time of Henry VI. (the 15th century), who made his chap-
lain, John Botterright, comptroller of all his mines of gold, silver, copper,
latten, lead, within the counties of Devon and Cornwall. In 1639 a
proclamation was issued prohibiting the importation of brass wire, and about
1650 a German called Demetrius established a brass work in Surrey at the
expense of £6,000, and employed above eight thousand men in brass works
near London and Nottingham. Yet in 1670 Sir John Pettus† says the brass
works were decayed and the art of making brass almost gone. In 1708 the
brass niakers in England presented a memorial to the House of Commons
soliciting the protection of Parliament. They stated "that by reason of
the inexhaustible plenty of calamine," England "might become the staple of
brass manufactory for itself and for foreign parts;" "that the continuing the
brass works in England would occasion plenty of rough copper to be brought
in, and make it the staple of copper and brass." In 1720 it was remarked by
W. Wood, in his work on the state of the copper and brass manufacture, that
this nation could supply itself with copper and brass of its own produce if
such duties were laid on foreign copper and brass as would discourage their
importation.
of
+
An ancient charter exists, of which we give a facsimile, of the date of
Edward IV. (about 1480), which, in a rude attempt at plan-drawing,
curiously, and still correctly, represents the "Myne deeps,” as they were then
called. Taking advantage of an offer made by an intelligent and scientific
friend to inquire if any other copies existed of the map which is in the
Mining Record office, I had the satisfaction of receiving an interesting letter,
which I annex.
"I have seen the map of the Mendip. It is very curious, and is a counter-
part of the documents you have. It is quite clean, and has been used as a
sort of panel in a good house. It is on canvas with a curious sort of framing
(painted wood), and is about 4 feet by 2 feet (less than 5 by 3). There is
painted the "Mendip Minerys-churches above and below, and land on each
side."
"The subject seems a counterpart in matter to your copies, but, I think, a
difference of person; in the preamble, after speaking of making a peace and
contentment,—the Prior of Green Ore is named,—and I do not remember that
in yours. Now Green Ore is two and a half, or three miles, from this spot,
and six from Wells-plain on the Mendips.
"It (the drawing) was found at Bristol at a curiosity shop, and brought
over to Wells by a surgeon, thinking some person would buy it, or that a
lottery could be got up to keep it in Wells. The price is £15.
"I heard that years ago at Axbridge another of these maps-supposed to
belong to some other court-was sold for £60 to a gentleman, at whose
Opera Mineralia Explicata." By Moses Stringer, M.D. 1713.
+ "Fodinæ Regales," p. 33.
"Opera Mineralia."
Berrington
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Crosby Lockwood and CP 7 Stationers Hall Court, London
Copied from an Ancient Document relative to
The Mines on the Mendin Hills.
THOP KELL & SON, LITH VO, KING
GARTEN
CHAP. V.]
THE LAWS OF THE MENDIPS.
135
decease, at a public sale, it fetched £30, and is bought for an institution. I
will get some of these names and particulars if I can, and something of
interest may come out of the affair.
"The medical man, a stranger, to me, said he had no other than local
interest in the affair, and had been a customer to the Bristol shop, and so it
had been lent to him to sell here.
"THOS. J. PEARSALL.”
This document, though exceedingly rude, contains a considerable amount
of information. The dogs hunting signify that the "Myne deeps," as they
were then called, were "a Royal Chase," and therefore preserved by the
Sovereign. All the churches signify so many parishes, and to a certain
extent the character of those have been preserved. The chief mines are
correctly placed, and the drawings at the side convey a fairly good idea of
the mining process employed at this date. On the original the “Laws of
the Myne deeps" were inscribed at the side of the map, and within the
space occupied by the drawings.
THE LAWES OF YE MYNEDEEPS.
BE IT RIGHT WELL KNOWN, That this is enrolled in the King's Highnesse
Exchequer by the time of Kinge Edward the Fourth of a great debate that
was in the county of Somsr. Between the Lord Bonville's Tenants of Chuton
and the Prior of Greene Ware. The said Prior complain'd unto King
Edward of great injuries and wrongs that he had upon Mynedeepe being
the King's fforrest. The said King Edward comanded my Lord Short, being
Chief Justice of England, to goe downe into the country of Meyndeepe and
sett a concord and pease in the country upon Meyndeepe upon paine of his
high Displeasure. The said Lord Shorte sate upon a place of my Lord of
Bathes called the fordge upon Meyndeepe. Whereas he comand. all the
commoners to appeare there, and in especiall the fowre Lords Royall of
Meyndeepe. That is to say, my Lord the Bishop of Bath and Wells, my
Lord Glastonbury, my Lord Bonville, Lord of Shuton, and my Lord of Rich-
mond, with all the appearance to the numbers of tenn thousand people. A
proclamation was made to anquire of all the saide company how they would
be ordered. Then they all with one assent made answer and said that they
would be order'd and tryed by the fowre Lords Royall. Then the fowre
Lords Royall were agreed that all the commoners of Meyndeepe dwelling in
their tenements, being within the said bounds of Meyndeepe, shoulde turn
out their cattle att their outletts as much the sumer as they be able to keepe
the winter without hounding or pounding upon whose grounde soever they
went to take their course and recourse. To this the said fowre Lords did
set their seales. And also weere agreed that whosoever shoulde breake
any of these bounds should forfeit to the King one thousand markes and all
the pleasure that doth either hound or pound.
THE OLD ANCIENT custom of the occupation of the Mynedries in and upon
the Kinges Majesties fforrest of Meyndeep w'th in his Majesties county of
Somer'et, being one of the fowre staples of England, which hath been verrified,
used, and continued through the said fforst oft from the time whereoft man
now living hath noo memories as hereafter doth particularly ensue ys.
136
[BOOK I.
HISTORICAL SKETCH.
I. FIRST, That if any man whatsoever he be that doth intend to wentor
his life to be a workman in the Myndery occupation, he must first oft. all
reqire lyence of the Lord of the Soyle where he doth purpose to worke, or in
his absence of his officer as Load Rove or Baylie, and in the Lord neither
his Bayliffe or officer can deny him go.
2. Item, That after the first lycence had the workman shall never need to
ask leave againe, but to be all his freewill or pitch within the saide fforrest,
and to breake ground wher and in what place it shall best like him to his
behoofe, and of it using himselfe justlie and trulie, &c.
3. Item, That every man that doth beg in his pitt or groove shall have
his hact throw two wayes after the rake; and note that he that doth throw
hact must stand in his pit or groove to the girdle or wast. And then no man
shall or may work within the compass of his said hacks throw.
4. Item, That when a workman hath landed oare he may carry the same
to cleansing and blowing to what Myndery he shall please for the more
speedy making of the same, for that he doe trulie pay the tenth thereof to
the Lord of the Soyle where it was landed.
5. Item, That if any Lord or his officer have once given lycence to any
man to build or sett upon any hearth or washing-house to wash and cleanse
and blow their oare, he who hath for once leave shall for ever keep it, sell it,
or give it to whom it shall please him for that he doe truly and justly pay
the lott lead which is the tenth pound that shall be blowne at the same
hearth. And also ift he do keepe it tenantable as the draft doth require.
6. Item, That if any man of that occupation doe pick or steale any lead
or lead oare to the value of viii.d. the Lord his officer may arrest all his lead
and oare, house or hearth, with all his grooves and workes, and keepe them
as forfeit to the owner. And shall take the person that hath so offended and
bring him where his house or worke, and all his tools and instruments
belonging to the same occupation be, and put him into his house or worke
and sett fire in all together about him and banish him from that occupation
before all the Meynders for ever.
7. Item, That if ever that person doe pick or steale there any more he
shall be try'd by the common law, for this custom and law hath no more to
doe with him.
8. Item, That every Lord of Soyle or Soyles ought to keep two Meyndrie
Courts by the year, and to gooard twelve men or more of the same occupation
for the orders of all misdemenowrs and wrongs touching the Meyndries.
9. Item, The Lord or Lords may make three manner of arrests (that is to
say), the first is for strife between man and man for their works under the
earth; the second is for his own duty for lead or oare wheresoever he find
it within the said fforrest; the third is upon ffelons goods off the same.
occupation whersoever he find it within the same hill.
10. Item, That if any man by the means of this doubtfull and dangerous
occupation do by misfortune take his death, as by falling the earth upon him,
by drowning, by stifling with fire (or otherwise as in times past may have
been), the workmen of the occupation are bound to fetch the body out of
the earth and bring him to Christian burial at their own proper costs and
charges although he be three score fathom under the earth as heretofore,
CHAP. V.]
<<
LEAD MINES AND CAVERNS.
137
Description by Mr. J. Beaumont (Phil. Col., n. 2, p. 1) of Lead Mines
and Caverns in the Mendips, from the Philosophical Transactions and Col-
lections to the end of the Year 1700. Abridged by John Lowthorp, M.A.,
F.A.S. (1705.)"
On the south side of the Mendip Hills, within a mile of Wells, is a
famous grotto, known by the name of Cokey Hole. This is fully described,
and a strange account given of the eels found in the river flowing through
the levels, and the bats which inhabit the vaulted passages, but no mineral
matter is found in it; but, "before you come to the middle of this vault, you
will find a bed of very fine sand, which is much sent for by artists to cast
metals in."
""
"About five miles from this, on the south-west part of the Mendip Hills,
near a place called Cheddar, lies another cavern. "These two caverns have
no communication with mines, but we generally observe that wheresoever
mines of lead ore are, there are caverns belonging to them. The most con-
siderable of these vaults I have known on Mendip Hills is on the most
northerly part of them, in a hill called Lamb, lying above the parish of
Harptry. Much ore has formerly been raised on this hill; and being told,
some years since, that a very great vault had been discovered there, I took
six miners and went to see it." The description which follows very closely
agrees with that already given.
Captain Sturmy, on the 2nd July, 1699, states "that he descended, by
ropes affixed at the top of an old lead ore pit at Pin-Park Hole, in Glou-
cester, 4 fathoms almost perpendicular, and from thence 3 fathoms more
obliquely, between two great rocks, where I found the mouth of this spacious
place, from which a mine-man and myself lowered ourselves by ropes
25 fathoms perpendicular, into a very large place, which resembled to us the
form of a horseshoe, for we stuck lighted candles all the way we went to
discover what we could find remarkable." They found a river 20 fathoms
broad and 8 fathoms deep! .
"As we were walking by this river, 32 fathoms under ground, we dis-
covered a great hollowness in a rock some 3 foot above us; so that I got a
ladder down to us, and the mine-man went up the ladder to that place, and
walked into it about 70 paces, till he lost sight of me, and from thence cheer-
fully called to me and told me he had found what he looked for, a rich mine.
But his joy was presently turned into amazement, and he returned affrighted
by the sight of an evil spirit!
“There are abundant of strange places, the flooring being a kind of
white stone cnamelled with lead ore, and the pendent rocks were glazed with
salt-Peter, which distilled upon them from above, and time had petryfy'd."
Sir Robert Southwell informs us that shortly after this expedition Cap-
tain Sturmy died, implying from the effects of damps in these vaults. Captain
Collins describes this cavern fully, and Mr. J. Gill affirms that, where water
is in such caverns, they never want air.
Mr. J. Beaumont, who has been already quoted, says, "There are in
Mendips, and generally where mines are, subterraneous vaults or grottoes,
whereof some which are pretty deep, and admit not air too freely, and have
other conditions required, are said by our miners to be quick, having ore
138
[BOOK I.
HISTORICAL SKETCH.
often in them, and still lively coloured earths, &c. &c.; others admitting air
two or three ways, and having in them black and moist rocks, and dry and
rotten shaly stones-dark earths, barren sand, and the like-being said to be
dead."
THE LAWS OF THE LEAD MINES IN DERBYSHIRE.-From the Bundle
of the Exchequer and the Inquisition of the year of the reign of King Edward I.,
16. (1288.)
The King appoints "Reynold of the Ley and William of Memill to
inquire by oaths of good and lawful men of your country" the liberty
which the miners claim. This command was given to “
"our well-beloved
cousin Edmond, Earl of Cornwall, at Westminster, the 28th day of April, in
the year of our reign the 16th.
"By William of Hambleton, and at the instance of Hugh of Cressing-
ham, the day is appointed at Ashbourne, upon Saturday next after the Feast
of the Holie Trinitie."
Twelve jurors were sworn, and the following laws were settled on, upon
their oaths:—
1. "Who say, upon their oaths, that in the beginning when the miners
did come to the field seeking for a mine, and finding a mine, they do come to
the bailiff, which is called burghmaster, and did desire (if it were a new field)
that they might have two meers of ground; that is to say, one for the finding
hereof, and the other by the miners' fine, viz. paying a meer dish of his
first oar."
2, 3, 4, settle the meer.
5. "The King shall have the thirteenth dish or measure of oar, which is
called The Lot.”
7, 8, 9, settle the rules for selling ore.
10 makes an exception of "a certain place, then called Man Dale, in
which place all buyers of oar are prohibited to buy oar for the space of four
years last past by the burghmaster.”
II settles "that the pleas or Courts of the burghmaster ought of right
to be kept and holden yeerlie upon the mines from three weeks to three
weeks."
The remaining clauses settle time, trespasses, and liabilities for "every
bloudshed."
THE LIBERTIES AND CUSTOMS.*-The first clause settles that "a meer
shall contain in length 10 wands and 7 feet, that is to say 87 feet.”
The miners to have their meer for ever—unless it be forfeited to the
lord.
Directions are given for the working of the meer, and the "Burghmaster
shall see that the mine be wrought duly." If he finds the mine neglected
“he shall score on the spindle one score, and so from week to week." If he
finds the mine unworked for three weeks together "he shall score three score
on the spindle and deliver it to him that will work it as the law will."
The miner is to be granted by the burghmaster a sufficient place “for his
* The "Mineral Laws of Derbyshire." These laws or customs remained in manuscript until they
were printed at London in 16mo, in 1688, under the title of the "Complete Miner." They were reprinted
in 1734 in 8vo, with additions by George Steer, and again in 1772 by William Hardy.
1
CHAP. V.] LAWS OF THE LEAD MINES OF DERBYSHIRE.
139
lodge and for his cottage with sufficient house-boot and hay-boot, and all
manner of timber for their groves."
The miners shall have for their beasts pasturing with the lord's beasts in
his wastes, and "no minister of the lord's shall pin them nor distrain them.”
"Also the stewards shall hold yearly on the mines at their own wills
courts, and two great courts every year; and if any miner or other person
be attaint for stealing of barmine, first he shall be amerced in it 5s. 4d., the
which 4d. the burghmaster shall have, and if he be attaint again the miner
shall be amerced 10s. 8d., the which 8d. the burghmaster shall have, and if
he be attainted the third time he shall be stricken through the right hand
in the palm with a knife up to the heft into the stow, and there shall he stand till
he be dead, or else cut himself loose, and then he shall forswear the franchise
of the mine."
The miner for any act of felony in the mine is to be fined £100.
"Each trespass of oathes or bloud shall be amerced 5s. 4d.," and the like.
"The miners and merchants shall have weights for their lead and measures
for their oar."
"If it happen that the miners or any other be dead in the grove or else-
where, no escheator or commoner nor no other officer of the lord shall meddle
of lands, goods nor chattels of him that is slain or dead by any misfortune,
but only the burghmaster of the mine."
"The lands and chattels of felons and fugitives shall be forfeited (if they
have no better grace).”
"The miner and merchant shall have free entrie and issue by all the
lordship to carry their mine, and carry it whither they list, without let of the
lord or any of his officers; but they shall give to the King for every lord
fourpence for ențrie and issue by his lordship, and that is called Cope; and if
any miner or merchant died by misadventure under the earth, or be slain by
chance medly, the burghmaster shall see his bodie as coroner, and let his
bodie be buried without any coroner."
“And the miners shall have for their lot and Cope sufficient timber for
their work (without any penie giving) of the next founder within the King's
lordship. Also they shall have water to wash their mine without any let for
the said lot and cope." (See page 140.)
"If the lord will buy their mine for as much as any other man will give
them, he shall have their mine before all other men," &c. &c.
"In witness thereof," &c. &c.
"These being the laws and customs of the mine used in the highest Peak,
and in all other places through England and Wales, for the which to be had
the wise miners sueth to our lord the King that he would confirm them by
his charter under his great seal in way of charitie.
"And for his profit, forasmuch as the aforesaid miners be at all times in
peril of their death, and that they have nothing in certain but that which
God of his grace will send them.
"FINIS.
"WILLIAM DEBANCKE."
The following Law of the Barmot deserves a brief notice: "Cur Magna
140
[BOOK I.
HISTORICAL SKETCH.
Barmot, TENT APUD WWKSWORTH CORAM, FRANCISCO (1550); Com. Salop
20 die Septembris Anno Regni Edward VI. &c. Tertio. Inquisitro Magna pro
Domino Rege Miner infra. Wapentag prædict. per Sacramen."
Twenty-four jurors whose names are given say, "We do present and set
down pains for the miners as followeth":—
The measures of ore were first settled.
Then they deal "with ground unjustly wrought." Ore-stealers and other
offenders are to be punished. Disputes as to "trials and for grounds in
variance."
'If there be any man that maketh title to any man's ground, contrary to
right, and it be tried by the law, he that is cast, shall pay two shillings for the
twelve men's dinners, and if he will not pay it then the burghmaster shall
take so much oar of him as cometh to two shillings, or else some other
distress if he be worth so much."
Debts are regulated, the holding of courts arranged, the payment of lot
settled, the fixing of crosses and holes to hold possession of ground, the
buying and selling of ore, gauge and counterfeit dishes to be kept, and the
settlement of groves and fines are finally adjusted.
Another set of laws were determined on in 1558: "Cur Magna Barmot.
Dom. Regis and Dom Regina Tent apud Wricksworth 3 Maii, Annis Regni,
Phillippi and Maria. Dei Gratia Regis and Reginæ Angliæ, Hispannæ
Francia, &c., tertio and quarto."
((
Inquisitro Magna pro Domino Rege & Domina pro Miner infra Wapentag
prædict secund consuetud ibidem usitat per Sacramen."
Twenty-four jurors settled-
1. That the lord should provide able dishes.
2. No miner to dig within seven feet of any man's washing-trough.
3. No ore to be sold if the owners are not on the ground.
4. Not to dig near any man's dwelling-place.
5. No purchaser shall stop a miner from using a wash-trough.
6. Barmasters to measure poor men's ore.
7. None to deliver ore except by the King's dish.
8. Allowing twelve men's dinners at the court of barmote.
9. Every miner must be lawfully summoned.
10. Stows, timber, picks, &c., not to be moved.
II. Possession not held by holes and crosses above three days.
12. Wood and water allowed by the King.
13. The Barmaster shall allow the miners to make a way to the water.
14. Miners' privileges.
Sundry rules follow as to the owner of a new vein, for regulating the
measures of ore, punishment for stealing ore from any grounds, and several
laws regulating the action of the Barmaster.
The old method of working lead mines in Derbyshire was as follows:* A
person having found a vein of ore, made certain crosses on the ground, as a
mark of temporary possession, and then went and informed the Barmaster,
who attended and received a measure or dish of ore, the first produce of the
* "General View of Agriculture and Minerals of Derbyshire." By John Farey, sen. 1811.
CHAP. V.]
WORKING OF MINES IN DERBYSHIRE.
141
mine, as the condition of permitting him to proceed in working his meer, or
measure of 29 yards in length of the vein; the Barmaster at the same time
taking possession of the next adjoining 14 yards, or half meer of the vein,
for the King. And if the vein seemed promising, it often happened that at
the same time, or soon after, there were various applications to be admitted
each to free his meer, or 29 yards in length of the rake vein in succession.
It was a condition, that each person or company possessing their meer or
meers in partnership, called groove-fellows, should immediately begin and
continue to work at their mine, as in case of intermission for three successive
weeks, the Barmaster was authorised to dispossess them, and give the mine
to another.
As these first mines were all in the district where the Limestone has no
other cover but the corn-soil, each miner went to work, and with mattocks
or picks, and with hammers and iron wedges in the harder veins, loosened
the ore and spar, and threw out the latter into a bank or ridge of their vestry
or bowse, on each side of the vein, proceeding thus to sink and throw out vein-
stuff, as deep as was practicable, when a square frame, composed of four
planks of wood laid across and pinned together at the corners, on which
two others were erected, with holes or notches to receive the spindles of a
turn-tree or rope-barrel, for winding up the ore in small tubs. This
apparatus, called a stowse, being erected on each meer, or mine, the sinking
was further continued, and the heaps on the sides of these open-works, or
open-casts increased until, in numerous instances, a perpendicular ditch, of
the width of the vein and many yards deep, was opened, with proportionally
large heaps of rubbish on each side, for many hundred yards in length, with
other similar veins and heaps parallel to and crossing them at certain angles.
Great numbers of the mines thus opened proved too poor in their pro-
duce of ore to be sunk lower than men could throw out the stuff, therefore the
miners abandoned them, after some progress had been made in deepening
them by means of stowses.*
*
"As the mines which proved richer in ore increased in depth, instead of
continuing to draw up the vein-stuff to the surface, the miners constructed
floors or stages of wood across the mine, called bunnings, just above
their heads, and on these threw the refuse or vestry for the whole length
of the mines, which thus became covered over, except just under the
stowses, or drawing apparatus, at which place they sunk six or eight feet
or more lower, and after clearing some distance, began other bunnings
under the former, on which the refuse was thrown as before. And as the
work thus proceeded, the shaft under the stowse was either lined with
timber or stone, called ginging it, and the vein-stuff which was drawn, being
thrown on to the bunnings on each side, a regular hill was at length formed,
and increased round each shaft, and is called the mine-hillock, or hillock.
In
process of time, as the mine increased in depth and having reached to
water in the strata, the drawing of such in barrels, and the ore and vein-
stuff which could not be stowed on the bunnings, so increased the labour
and expense that many valuable mines were abandoned on that account,
* Similar modes of opening and working lead veins have been practised in the island of Islay, in
Scotland. (See Williams's "Mineral Kingdom,” 2nd ed. i. p. 275.)
142
[BOOK I.
HISTORICAL SKETCH.
until horse-gins were erected for drawing the water and ore, and loughs
began to be driven for drawing off the water.
Farey thus explains the loughs or levels:* "Where deep valleys intersect
a mineral district, it is often found practicable to begin in the valleys, and
by driving or cutting a small tunnel, lough, or water-level, and support-
ing the same with wood, stone, or bricks, to relieve or lay dry the mineral
vein."
"The mines or meers of ground became consolidated, or the property of
them united, and the mines being connected below, the ore and vein-stuff
was carried to particular shafts, to be drawn, and on the hillocks, of which
coes, or small buildings, were in time erected for stowing the ore, tools, &c.,
and sheds for the accommodation of the ore-dressers, or those who separated
the smaller portions of ore from the vein-stuff, a process which was probably
little attended to in the earlier periods of these mines."
"All the lead ore which is dressed ready for sale in the King's field is
obliged to be measured in the presence of the barmaster before it is removed
from the mine, for which purpose a rectangular box is used in the Low Peak
28 inches long, 6 wide, and 4 deep, called a dish, and reputed to hold 14
Winchester pints, when level full; while in the High Peak 16 pints are
reckoned to the dish.
"In measuring the ore at present (1811), every twenty-fifth dish which is
measured is taken or set aside by the barmaster, as the King's lot, cope, or
duty; and in case of a composition being due to soughers, who free the
mine of water, at one-sixth in Wirksworth, and of tithe being payable as one
fortieth in the same place, the barmaster causes every sixth and every fortieth
dish which is measured to be set aside or laid in a separate heap for the use
of the parties, and so of the lord of the manor's dues, if any such are payable
where the mine is situated, as at Crich, &c. The meer in a pipe-work, or
horizontally extended mine, is fourteen yards square."
Farey further describes the methods of working Lead Mines as follows.
The practices described do not appear to have undergone any change
through the eighteenth century, and were continued until the nineteenth
century nearly unaltered: "Except where horse-gins are used, it is not
common to sink very deep drawing-shafts to lead mines, especially as
dividing the same into several lifts or turns often suits the trade of the mine,
such turns or under-ground shafts being connected with each other, by
means of short thurls, or horizontal galleries. The persons who sink mine-
shafts are generally called shafts-men, and those who drive levels or gates,
level-men, or gate-men. The miners who dig the ore are usually called
copers, from their working at a certain cope, or price per ton or per load of
ore which they get. In some large works the price per ton or per load is
fixed at the commencement of each quarter; but where the mine is tolerably
productive, bargains of this nature are generally made twice in the quarter,
viz. for six or for seven weeks alternately. It is not customary for the
owners to advance any of the cope-money on account, but at the end of the
bargain, the miners having dressed up the ore that they have got, it is
weighed, if by the ton, or measured if by the load, in the presence of the
* Farey's "Derbyshire."
OLD METHOD OF GETTING LEAD ORE.
143
CHAP. V.]
barmaster and his employers, and at the pay-day, which is usually a fort-
night after the ending of the quarter or half-quarter, they receive the money
for the quarter's reckoning.
"In the working of the deep rake veins, a roof of Bunnings, or of shale or
toadstone, may be supposed over the miners' heads, who in some works
drive only one stoop of work, that is, a height of four or six feet before them;
while in others, where many men are employed, two or three stoops are
carried on at the same time, the upper one being kept forward two or three
yards, and the next as much before the lower one or sole, like steps, by
which means the miners do not interfere with each other materially."
"The face of a stoop or forefield of the mine is seldom worked upright or
straight, but is hollow in the middle, to suit the swing of the miner's pick, many
of whom pride themselves much on the neatness of the face of work which
they preserve, in moderately hard veins, where the pick alone is sufficient for
the work. In Gang mine, where a slickenside runs through the vein, the miner
avails himself of a curious property attending such veins, by drawing laces,
stoops, or nicks, at about six inches apart and four inches deep, with the
point of his pick from top to bottom of his face of work, which he then leaves
for several hours, and, on his return, finds all the vein-stuff is furrowed,
spelled, or slappeted off, and laying on the sole ready got to his hands. But
it more commonly happens that strong picks, hammers, and strong iron
wedges, or even frequent blasts of gunpowder, are necessary for loosening
and getting the ore and spar, the former of which, as well as the lumps of
spar or vein-stuff which he judges to contain ore, the coper collects into
shallow oval spel baskets called whiskets, and these are taken from him by
the boys called setters-on, who carry the same a stage of about twelve yards
along the hole or gate of the mine, and then hand them to other boys who
carry them a similar stage, each returning with an empty basket, until the
stuff thus reaches the kibble or small barrel at the bottom of a turn or under-
ground shaft, which kibbles, when full, are wound up by the turn-drawers,
who convey it to another turn, and so on, until the kibble of stuff reaches
the top, unless horse-gins are used, when the setters-on carry their whiskets
of stuff to the bridging-floor or foot of the shaft, when the bridger empties
them into a larger tub called the gear-barrel, which, when full, is drawn up
the shaft.
"The Coper or miner throws the refuse vein-stuff and parts of small riders,
or the skirts of narrow parts of the vein which he has found it necessary to
blast or cut down, behind him in the sole, until a shift or shift and a half of
work is performed, when he begins drawing the bunning or stemples forward.
This consists in forming a hole in the solid side or skirt, striking out a sort of
upright mortice in the skirt, whose bottom is level with the opposite hole. He
then chooses or cuts a stemple or booth of the right length—that is, a piece
of wood of the size of a man's arm, or larger according to circumstances,
having one end cut to a round blunt point, called the egg end, and the other
square and a little lessened, called the head.
"This round point he enters into the hole cut in the skirt, and the other
into the top of the mortice, or groove cut in the opposite skirt, and then by
hammer or his mattock drives the square end down to the bottom of the
144
[BOOK I.
HISTORICAL SKETCH.
mortice, by which means the stemple becomes a firm and immovable
strut across the vein; when four or five of the stemples are thus fixed,
flat pieces of wood, called fails, are laid across these, and then the coper
proceeds to lay up his deads, or pieces that contain no ore, on to these
fails, called the bunning; after building up a kind of wall in front with
the larger lumps, the remainder are thrown over this on to the fails;
more of the stemples and fails are then fixed, and the deads are thrown on
them, until the sole is quite cleared, when the getting of the ore is resumed
as before.
"Previous to the use of gunpowder in mining, fires of dry wood were
made against the forefield of the vein, which, owing to the heat, loosened
and slappeted off. The mining laws provide that such fires should not be
lighted or any smoke made in a mine during mine hours, or mineral time
of the day, that is, from eight to four o'clock. By means of those fires it is
surprising to see what narrow veins, mere scrins, the old men contrived to
work for great distances into the rock, using long-handled rakes or hoes to
draw out the loosened ore and spar, and hence the name of rake veins is said
to have originated.”
Farey gives the following as the names of lead ores in Derbyshire, "with
reference either to size, purity, structure, or kind:" belland, bing, blue,
fell, galena, glance, goods, green, hillock, lead-glance, leaf, peasy, pippin, potters,
scrogs, smitham, steel-grained, tag'd, toots, white, wicks, yellow, &c. This shows
that the lead ores of Derbyshire are very numerous, but the general produce
is galena (sulphuret or sulphide of lead, or blue lead ore) crystallised in
cubes; but square and hexagonal pyramids and other forms of this lead ore
sometimes occur.
“Within a few past years (1811) the miners of Derbyshire have discovered
a white lead ore (carbonate of lead), which was previously taken for a useless
spar, and was either left in the mines or buried in the old hillocks, from
which considerable quantities have since been extracted. This carbonate of
lead is often called wheatstone" (Farey). In nearly all cases this white
carbonate of lead is the result of the decomposition of the sulphide of lead
(galena), either by the action of air or water.
A Green Lead Ore, probably a phosphate, has been found in Brassington,
Great Hucklow, Tideswell, and Winster; and, according to Farey, also in
the following mines: Calver, Flagg, Great Longedon, Hartington, Hassop,
Mongash, Sheldon, Wensley, and Wirksworth.
The mode of selling lead ore at the end of the last century was evidently
of considerable antiquity. A very clear account is given by Farey, and, as
it is curious, his words are retained :-
"Formerly it seems that considerable quantities of the Derbyshire lead
ore selected from the largest and most pure, or Bing ore, was sold in that
state to the Staffordshire and other potters to grind, for preparing the glazes
of their common wares, and hence such was called potter's ore; but at present
all the lead ore of the county, and even that produced by the mines in
Warslow in Staffordshire (with the exception of Acton, where the Duke of
Devonshire has a cupola for his own ore) is brought into Derbyshire to be
smelted. Owing to the division of the mines in Derbyshire into such
CHAP. V.]
SELLING AND SMELTING LEAD ORES.
*
145
numerous shares, no miner in Derbyshire now maintains a cupola.*
Formerly, when the mines of Derbyshire were in their most flourishing state,
there were markets at Wirksworth, Winster, Chesterfield, and some other
places, but such is not now the practice, for almost every miner, sougher, or
tithe-owner, &c., has some smelter to whom he sells his ore regularly, and
such smelter attends the ore-measurings."
The price of lead at Hull in Yorkshire seems to be the rule principally
followed in fixing the price of ore from time to time in Derbyshire;
and though the ancient method of measuring ore is still adhered to, yet
weight and scales are now generally used in the ore-cob at the time of
measuring, and three dishes at least, taken indiscriminately from each of
three sorts of ore, viz. bing, peasy, and smitham (belland being always sold
by weight at the rate of 53 to 60 lbs. per dish), are weighed, and the average
is noted by the barmaster and buyers present. The usual practice of the
smelters was to consider 58 lbs. as the standard weight of a 14-pint dish of
ore, and to allow the miners, to whom they were regular customers, half the
price per ton for their ore that lead bore per Fother or Fodder at Hull
(2,340 lbs.) at the time of taking up each parcel of ore, and that parcels
of ore weighing less or more than the above standard weight per dish (from
the average of three dishes as above), were deducted from, or allowed extra
at the rate of 10s. per ton of ore for each pound that the dish fell short
or exceeded the standard.
"The carriage of ore (1790), in common with that of every other article,
was on pack-horses formerly, a drove of such horses being called a jag, and
persons carrying ore for hire were called ore-jaggers, a name still (1802)
applied, though carts and waggons are universally used in these parts,
except a few pack-horses that may yet be seen about Buxton, Hathersage,
and the very mountainous parts, the mules used in bringing coals and ore to
the Whiston copper works in Staffordshire, and the horses and asses used to
supply some of the poor with coals from the pits in different parts. The
average price of carrying ore in 1808 appears to have been is. per ton per
mile” (Farey).
In the boyhood of the author droves of mules were to be constantly seen
in Cornwall carrying the tin ore from the mines to the tin smelting-houses.
In the early periods of mining, in Derbyshire as in other places, the ore
was smelted on the tops or western brows of high hills-these being chosen
as being most exposed to the prevailing winds-by fires made of wood, and
* Bache Thornhill, Esq., of Staunton, in the Peak, is the only person in Derbyshire who works lead
mines of any consequence on his own account (the end of 1700) without partnership. Sir Joseph Banks
began to sink some shafts at Overton for the purpose of employing the miners who were suffering by the
stopping of Gregory and Westedge mines.
"In general as small shares as 48-ths, 96-ths, or even 384-ths, and 768-ths are held in the Derbyshire
mines, and the very smallest mines have often many partners concerned in them, originating in the mode
of gianting tithes originally by the barmaster. The facility with which shares are sold and transferred,
by entry in the barmaster's book, and in numerous consolidations of tithes, which have necessarily
taken place to form large works, such as what is now (1802) called the Gang Mine, and others of that
class. The owners of manors and estates within the King's field, who are possessed of mineral rights,
none of them commute with the miners for fixed rents, but all take their cope or share of ore in kind,
at each ore-weighing, as the King, the soughers and the tithe-owners, to which last impost is paid only
in Eyham parish, and in Wirksworth, including Cromford and Middleton. The pretence of claiming
tithe of lead one is said to have been that the ore grew and renewed in the vein. In 1780 the gentlemen
miners met the clergymen, and agreed on 1-20th as the tithe-owner's share; but the miners all resolved to
pay no more than 1-40th."-Farey.
L
146
[BOOK I.
HISTORICAL SKETCH
blown by the wind only. Piles of stones were made round the fire, and
probably arches formed underneath them, to favour and increase the action
of the wind.
These old hearths were called boles, whence many of the highest hills
near the lead districts obtain their names. Anciently the miners claimed the
right of cutting wood and timber for the use of the mines, and for smelting,
not only from all wastes and forests within the King's field, but from any
other of the King's forests; and Farey says, "There are people living yet
(1802) in Matlock who have assisted in fetching timber under this privilege
from Needwood Forest, in Staffordshire, for the use of their mines in
Matlock."
"It seems probable that the ports of the Trent
and the Humber were always the destination of the pieces, or half pigs, of
lead made in Derbyshire, from the distance which the ancient boles stretch
out in an eastern direction from the Limestone district in which the mines are
found, and hence Chesterfield was always a great mart for lead, and particu-
larly so since the opening of the Chesterfield Canal to the Trent in 1776.”
In 1800 the following ancient boles were known to have existed :-
Bank (near Holmsfield), half-mile S.W.
Baslow, N.E. of the colliery.
Bole Hill, S. of Sheldon, in Bakewell.
Ditto, quarter mile N.W. of Upper Hurst, in Hatherage.
Ditto, S.W. of Ningerworth.
Ditto, N.W. of ditto.
Chatsworth Old Park Plantation, S.E. of Baslow.
Cold Harbour, in Lea.
Cromford Moor, S. of the Bridge.
Eyam.
Holy-moor Top, N.E. of Harwood cupola.
Matlock.
Slag Hills, S. of Batherley.
Stanton, in the Peak.
Three-birches, Pudding-pie Hill, W. of Brampton.
Unthank, quarter-mile W. in Dronfield.
Farey informs us: "These very ancient boles, or wind-hearths, were
succeeded by slag-mills, or treadles, almost like a blacksmith's forge on a
large scale, blown by bellows, worked by men or by water, one of which
is still seen (1801) attached to each of the cupolas that can command
a stream of water. Near one of these ancient slag-mills in Bonsale Dale,
the slag of it used some years ago to be laid into the road, to be ground to
dirt by the wheels of carriages, and then used to be scraped up and dried
and remelted on the hearth, and strong iron rollers were used for crushing
the slag for the same purpose. At the old hearth at Harleford Bridge, S. of
Hathersage, such waste of ore was formerly made as to have employed a
set of buddlers for ten years past, turning over the rubbish for three yards
deep or more. Some of the ore thus obtained seemed to have passed through
the fire and some not, which I account for by the floods of the Derwent,
which have probably at different periods swept down their mills, coes, &c.
Thirteen hundredweight of the ore and slag thus procured, generally pro-
CHAP. V.]
LIST OF CUPOLAS AND SLAG-MILLS.
147
duced from one and a half to four pieces of lead at the cupola, as the buddlers
informed me.
"Anciently, it seems, that the Crown claimed the right of smelting all
the lead ore which was obtained in the King's field, and took toll or duty of
it; and it is said that their boles were so ill-managed, and the exactions at
them were such that the mines were in a great measure disused, until at
length, in order to revive the mining of the district, the Crown agreed to
accept 6d. per load of nine dishes of ore from the smelter in lieu of the
smelting claim, which continues yet to be paid to the barmaster at the time
of measuring ore. The mines within the manor of Haddon and Hartle were
also restricted by the custom of those manors from smelting their lead but
at the lord's hearth, which occasioned the Duke of Rutland to maintain
one of the old hearths at the N.W. of Great Rowsley village, long after they
had been elsewhere disused. At length, about 1780, the miners agreed to
pay 9d. per load (of 144 pints) to his Grace to be at liberty to smelt their
ore where they pleased, and this last of the hearths for smelting ore was
disused and pulled down. The remains of one of these old slag-mills, with
some slag but imperfectly deprived of its lead, was found 200 yards N. of
Somerester iron-furnace in Alfreton."
The cupolas, or low-arched reverberatory furnaces, now (1801) exclusively
used for the smelting of lead ore in Derbyshire, were introduced from Wales
by a company of Quakers about the year 1747, the first of which was erected
at Kelstedge, in Ashover, but this is now disused and pulled down, as will
be seen from the following List of Cupolas in, and near, Derbyshire :-
Barber-fields, in Dronfield (formerly).
Barbrook, in Baslow (and Slag-mill), T. and J. Barker.
Bonsal Dale (and Slag-mill), Evans and Co.
Bradwell, Benjamin Barber.
Bretton, in Eyam, Samuel White.
Calow, E. of Hathersage, late Wm. Longdon.
Copy Nook, in Stanton Harold, Leicestershire, Earl Ferrers.
Cromford Moor (Steeple House), Charles Hurt.
Devil's Bowling Alley, in Alderwasley, Francis Hurt.
Ecton, in Warslow (and Slag-mill), Duke of Devonshire.
Harwood Moor, near Loads, George Barker and Co.
Kestledge, in Ashover (two formerly).
Lea, near Cromford (and Slag-mills), Shore and Co.
Lermsdale, in Matlock (formerly).
Middleton Dale, in Stony Middleton, George Barker and Co.
Stannage, in Ashover (and Slag-mill), Sykes, Milnes, and Co.
Stannage, ditto, George Barker and Co.
Tutley (and Slag-mill), George B. Breaves.
Via Gellia, in Bonsel Dale, Saxleby and Co.
Weddsworth, E. of the town, Charles Huart.
Farey remarks, when he published this list, 1801, "Several of the smelters
are doing but little, and some have their works shut up occasionally, owing
to the supply of ore being now greatly inferior to what it was about twenty
years ago (1780). At Middleton Dale ore is smelted for the miners and
L 2
148
[BOOK I.
HISTORICAL SKETCH.
'buddlers' at 14s. for a charge of ore, usually about 18 cwt., and 13s. for a
charge of 'belland' or dust ore, usually about 12 cwt., and in these cases the
miners sell their pieces of lead, instead of their ore, to some of the smelters,
who are, I believe, the only lead-dealers in the district."
CUMBERLAND.-The early history of the mining district of Alston Moor is
but little known. There is satisfactory evidence that the Romans penetrated
into this region, silver denarii having been found at Hallhill, near the town of
Alston. Mr. Thomas Sopwith* remarks: "It is improbable that so exten-
sive a work as the great Maiden Way, or great Military Road, constructed
by that warlike people (the Romans) would be prosecuted without discovering
lead ore in some of the numerous veins which it crosses; and, at the Roman
station at Witley, in Northumberland, pieces of lead have been found, as
well as in numerous other places."
There is satisfactory evidence of the antiquity of mining in the charters
granted to the miners of "Alderston."
They had royal protection in 1233, and renewed in 1236 and 1237.
In 1282, Richard II. granted to Nicholas de Veteripont (Vipond) "the manor
of Alderston, to hold in fee of the King of Scotland," reserving to himself and
the miner various privileges, especially such as belonged to the franchise of
Tindale, within which Alston was then comprised. The miners, who farmed
their mines of the King, and worked veins containing silver ore (this is not
correct; they worked veins of lead, which produced several ounces of silver
to the ton), claimed a right to take any wood that should be near their
mines, and also at their will and pleasure to use and dispose of such wood
for burning, dispersing, and smelting; for paying the workmen their wages,
and to give to the poor workmen of the mines.
These claims were disputed by Henry de Whitby and his wife Joan,
"who
impleaded" several of the miners for cutting down and carrying away their
trees; and further charged them with having sold large quantities of wood
from which the King received no benefit.
King Edward III., in the seventh year of his reign, confirmed the privi-
leges previously granted to Robert, son of Nicholas de Veteripont; and in
the following year the "monetarie," or coiners, had their liberties confirmed
by the King. This proves that the silver obtained from the lead raised was
coined within the manor of Alston. In the twenty-fourth year of Edward
the Crown "exemplified some charters of privileges; and again, in 1356,
very large additional privileges were granted."
Henry V. let the manor and mines of Alston to William Stapleton, Esq.,
at an annual fee-farm rent of 10 marks, payable at the exchequer of Carlisle.
Alston afterwards became the property of the Hyltons of Hylton Castle,
in the county of Durham; and in 1611 a considerable portion of the lower
parts of the manor, adjoining the rivers Tyne and Nent, was granted in leases
for 999 years by Henry Hylton, subject to the payment of certain annual
rents, which amounted to £64, but, with some encroachments taken off, are
now £53, and a fine of twenty times the rent every twenty-one years.
The following is a copy of portions of a "Lease from Henry Hilton to
* "An Account of the Mining District of Alston Moor, Weardale, and Teesdale, in Cumberland
and Durham." By T. Sopwith, Land and Mine Surveyor, Alnwick. 1833.
CHAP. V.]
MINING LEASE FOR ALSTON MOOR.
149
Henry Wallas, of a tenement in Alston Moor for one thousand years," which
was granted in the year 1611:-
"This indenture, made the last day of August, in the eighth year of the
reign of our Sovereign Lord James, by the grace of God, of England, France,
and Ireland, King, defender of the faith, &c., and of his reign in Scotland the
five and fortieth, and in the year of our Lord God 1611, between Henry
Hilton of Hilton, within the county palatine of Durham, esquire, of the one
part, and Henry Wallas of Wanwood, within Alston Moor, in the county of
Cumberland, yeoman, of the other part, &c.
""
"Now that the said Henry Hilton, son and heir of the said Thomas
Hilton, as well as in consideration of the sum of four hundred pounds of
lawful money of England to him the said Henry Hilton, to be paid by the
said Henry Wallas and the rest of the tenants of the said Henry Hilton in
Alston Moor, for the payment whereof the said Henry Wallas and the rest
of the tenants have given such security to the said Henry Hilton every man
for his part and portion of the said four hundred pounds as the said Henry
Hilton hath accepted, as also in consideration of twenty years' rent to be
paid unto the said Henry Hilton, his heirs, executors, administrators, and
assigns, or some of them, for a general gersome and fine, at the first of all
the tenants of the said Henry Hilton, in Alston Moor aforesaid, their heirs,
executors, administrators, and assigns, and every one of them severally,
and so on. Again, "Henry Wallas shall well and truly satisfy, content, and
pay unto the said Henry Hilton, his executors or assigns, the sum of
£14 18s. 4d., of good and lawful money of England, being the full and entire
sum of twenty years' rent hereby reserved upon the messuages, lands, and
tenements, that is to say, £7 9s. 2d. thereof at St. Andrew's Day next ensuing,
and £7 9s. 2d. to be paid at St. Andrew's Day which shall be in the year of
our Lord 1611, which said sum is for a fine and gersome of the first twenty-one
years from the beginning of this lease, &c.; and all other easements, profits,
and commodities whatsoever to the said messuage or tenement, and all other
the premises belonging or in anywise appertaining, or thereof accounted,
reputed, or taken as part or parcel, or used and occupied as part and parcel
thereof, together with house boot and hedge, boot to be taken at the sight
of the officer there for the time being, so often and at all times when need
shall require, and as it hath been used and accustomed to be spent or used
in or upon the said messuage or tenement and other premises, to have and
to hold, occupy, possess, and enjoy the said messuage and tenement, and all
other the premises with the appurtenances thereunto belonging, from the
9th day of the month of September which shall be in the year of our Lord
1621, unto him the said Henry Wallas, his executors, administrators, and
assigns, and every of them, unto the full end of the term of 1,000 years
therein next after ensuing, fully to be compleat, fulfilled, and ended. Such
other person or persons as shall happen to have the interest of this lease
shall well and truly, from time to time, after the expiration of every number
of twenty-one years, so often as twenty-one years shall by effluction of time
be spent and run out, to be accounted and reckoned after the beginning
thereof, satisfy, content, and pay, or cause to be well and truly satisfied,
contented, and paid unto the said Henry Hilton, his heirs and assigns, or to
150
[BOOK I.
HISTORICAL SKETCH.
such person or persons as shall happen to have immediate reversion of the
premises, or to some of them, the sum of £14 18s. 4d., of good and lawful
money of England, in the name of a fine or gersome, being twenty years'
rent, herein by these presents reserved at or upon the end or expiration of
every twenty-one years, as often as the number of twenty-one, years shall
by effluction of time run out during the said term of 1,000 years, the said
several sums of £14 18s. 4d., so often as they shall happen to grow due
during the said term, to be paid in this manner and form, that is to say,
£7 9s. 2d., being the one-half thereof, to be paid at or upon the Feast of
St. Andrew," &c. &c. &c.
Many such leases are in the custody of Mr. Adam Walton, the moor-
master of Alston Moor, and are still preserved in Lowbyer Manor Office,
Alston.
In 1629, the lead mines, after a survey had been made, were reported to
be nearly exhausted; and the whole manor, with houses at Lowbyer and
Mack Close, and a corn-mill at Alston, was sold to Sir Edward Radcliffe for
£2,500, and remained in that family till the confiscation of the estates of
James, Earl of Derwentwater, in 1716. The mines were granted in 1734 to
the Royal Hospital for Seamen at Greenwich, and the manor remained in
the hands of commissioners and governors in trust for that institution until,
on the Government abandoning the system of the Hospital at Greenwich, it
was transferred to the Admiralty.
The evidences of copper having been formerly worked on Alston consist
of a copper wire, or a cart-pin, in possession of a gentleman at Allenheade,
and a spoon of the same metal, found in 1829 (Sopwith).
In 1760, Sir Walter Calverley Blackett introduced many improvements
in the system of working the lead mines in this locality. Mr. Smeaton,
the celebrated engineer, was for three years one of the receivers of the
Freemond Hospital estates, and he projected and commenced the aque-
duct of Nentforth Level, and he introduced cast-iron railways into the
London Lead Company's works. To Smeaton is also due the discovery of
the Rampgill vein, or, more strictly speaking, of its amazing value.
In 1780, Messrs. Walton & Co. bought a mine at Nenthead for £205,
and being fortunate, they engaged in several other mines on Alston Moor.
In 1782 they began to work in Farnberry vein, which was supposed to be
exhausted, and they were richly rewarded for their bold adventure.
Tin pipes were first used by Lord Carlisle and Co. for ventilating in Tyne-
bottom mine. Mr. Stagg introduced iron pipes at Rampgill, and Mr.
Thomas Dickinson, the moor-master, of Alston Moor, made use of lead
pipes for the same purpose in ventilating Nentforth Level.
In 1796, a Cornish miner, Richard Trathen, introduced an improved
mode of washing lead ores, and, from the slimes rejected by less experienced
washers, he obtained much wealth.
Such was the condition of lead mining in Alston Moor at the close of the
eighteenth century.
The mines of The Lake District-around Keswick-are of great antiquity.
"Indeed," says Mr. John Postlethwaite,* "there is good reason for believing
* John Postlethwaite's "Mines and Mining in the Lake District.”
CHAP. V.]
MINING IN CARDIGANSHIRE.
151
that mining has been carried on in this district for about two thousand years,
and much of the history of the Lake country is associated with its mines."
In "Camden's Britannia," Keswick is spoken of as "a little market-
town, long since noted for its mines, as appears from a certain charter
of Edward IV., and at present inhabited by miners." This will be about 1607..
Of Derwentwater the same authority writes: "It contains three islands, one
the seat of the Ratcliffe family, the second supposed to be the one on which
St. Herbert lived a hermit's life, and a third inhabited by German miners.” *
The Barrow mine is a very ancient one, having been wrought extensively
with "stops and feather" long before gunpowder was employed.
Roughtengill mine was in all probability worked at the same time as
Barrow, as was also Higgeth and Haygill mines.
The copper mines of this district are noticed in the previous chapter.
CARDIGANSHIRE.-We have no account of any mining operations in
Cardiganshire which can be considered authentic previously to the reign
of Henry VII. (1485). In the "History and Antiquities of the County of
Cardiganshire," by Samuel Rush Meyrick, published in 1810, the author
speculates on the probability that the Britons wrought the mines of
Cardiganshire for silver and gold. He infers this chiefly from the Triad
which celebrates Caswallan, Manawydan, and Llew Llawgyfes as three chief-
tains distinguished by the possession of golden cars. Meyrick states that no
Roman coins, or any vestiges of Roman workings, have been found in
Cardiganshire. However, since 1810, coins, evidently Roman, have been
found near Aberystwith. Sir John Pettus, in his "Fodinæ Regales," pub-
lished in 1670, says: "These works in Wales, with some others in Devonshire,
Somersetshire, and Cornwall, as far as tradition can assure us, were anciently
wrought by the Romans; by the Danmonii in Devonshire and Cornwall,
by the Belgæ in Somersetshire, and by the Dimetæ in Cardiganshire." He
gives some drawings of lead mines in his book, and designates them as the
Roman mines, but their being Roman workings is doubtful.
King Henry VII., in the first year of his reign, created by letters patent
Jasper, Duke of Bedford, and others, "earls, lords, and knights, com-
missioners of all his mines of gold, silver, tin, lead, and copper, in England
and Wales, Sir William Taylor being made the comptroller of this com-
mission. We have no reliable information of the action taken by this com-
mission. Little appears to have been effected during the reign of Henry VII.
or in that of Henry VIII. Sir J. Pettus† says: "But before Henry VIII. his
death, almost all the treasures of his father and his own were consumed, and
what remained was left to Edward VI., an infant, whose experience would not
guide him to the care of such affairs. Then followed Queen Mary," in
whose reign the mining commission was neglected, and "stood neglected
above seventy years." The earliest intimations we have of the real produce
of any of the mines in Cardigan is that given in a trial as to a "Mines Royal"
in Westminster Hall. Est-kyr-hyr was claimed as a mine rich in silver, and
therefore a Mines Royal. Proof is said to have been given in the court that
this mine produced lead giving 60 lbs. of silver in every ton, whilst the
* Gibson's " Camden's Britannia."
"Fodinæ Regales."
152
[BOOK I.
HISTORICAL SKETCH.
proprietor stated that it only contained to the value of 4 lbs. of silver to the
ton.
"
It has been already stated that Elizabeth caused several German miners
to be brought into this kingdom. Houghsetter was one of these, and
he with his family settled in Cardiganshire, and for four years actively
prosecuted the search for mineral treasures over that county. The Cor-
poration of Mines Royal worked for several years many of the lead
mines of Cardiganshire. Sir J. Pettus says these were the "Mines Royal
at Coomsumblock and the Darren Hills, Cwmervin, Goginean, Talybont,
Coomustwith, Tredole, Thruscott, and Rossvawre, which were the old
Roman works." He remarks, "They wrought several mines with good
success," but they were eventually let for the annual rental of £400. They
could not, therefore, have been very profitable.
The mines of Cardiganshire became, during the latter half of the
sixteenth century, the property of Sir Hugh Middleton, who was the sixth
son of Richard Middleton, governor of Denbigh Castle in the reigns of
Mary and Elizabeth. He is said to have, in the first place, sought for coal.
Being disappointed in finding any, he settled in London, as a goldsmith, and
then farmed the principal lead mines from the Governor and Company of
Mines Royal for £400 per annum.
Hugh Middleton drained the mines more effectually than they had
hitherto been, and working them deeper than the German miners appear to
have done, he was successful in finding very rich lead ore. It is said that
the ore of one mine-probably Cwm-symlog-yielded 100 ounces of silver
to the ton of lead. It is certain that he realised a large fortune from
his speculations in the Cardiganshire mines. A profit of £2,000 a month
is stated to have been derived from Cwm-symlog and the neighbouring
mines.t
It is recorded that in 1604 three thousand ounces of Welsh bullion were
minted at one time in the Tower. Hugh Middleton was a man with con-
siderable energy and determination. In 1608 he proposed to bring the New
River from Ware to London, promising the Lord Mayor that the undertaking
should be finished in five years. Upon this truly national work the profits
of the Cardiganshire mines were expended, and Middleton was obliged to
apply to the Government for money to complete his task. James I., with
his Court and the Lord Mayor, witnessed the first issue of the water from the
head at Islington, and the King conferred the honour of knighthood on
Middleton, and subsequently a baronetcy.
After the execution of this great work Sir Hugh Middleton appears to
have become so poor as to be under the necessity of working as a sur-
veyor. We, however, find him in 1639 disputing with Sir Richard Pryse
about the mines of Talybont, and a trial of considerable importance was
the result. Sir J. Pettus thus quaintly notices the fate of Sir Hugh
Middleton :—
“Had he not diverted his great gains to the making of the New River
from Ware to London, certainly he would have been the master of a mass of
* Watson's "Chemical Essays," vol. iii. p. 307, ed. 1782.
"Opera Mineralia Explicata," and Watson's "Chemical Essays."
CHAP. V.]
THOMAS BUSHELL IN CARDIGANSHIRE.
153
wealth; but great wits and purses seldom know how to give bounds to their
designments, and by undertaking too many things fail."
"*
Until the year 1641 the Earls of Pembroke continued the governors of
the Company of Mines Royal, but from 1647 no governor was chosen. The
mines of Cardiganshire were actively worked by Mr. Thomas Bushell, who
was the secretary of Sir Francis Bacon. Bushell was a man pretending to
some scientific acquirements, and certainly possessing good literary capa-
bilities. He published, in 1642, “A Just and True Remonstrance of His
Majesty's Mines Royal in the Principality of Wales;" also "The Case of
Thomas Bushell truly stated, with his Progress in Minerals," in 1649.
Several other publications issued from his pen, and he edited a new edition
of "Bacon's Articles of Inquiry." Bushell states that "In the mountains
of Broomflyd, Talybont, Goginan, Cwm-erven, and Darren, there were great
quantities of lead and silver, and I bought those mines, which had been
granted to Lady Middleton by King James for £400 down, and £400 per
annum during the continuance of her interest therein." Mr. Bushell worked
those mines deeper than Middleton had done, and at Cwm-symlog, "he,
being flushed with this (Sir Hugh Middleton's) success, cut a measured mile
to find this vein, to three and four yard deepness, at no small charge; and
seeing Sir Hugh, by an engine, had wrought it several yards under water,
the patentees endeavoured to bring up an adit to go under this work at
the expense of £10,000." The patentees named appear to have been Sir
Francis Godolphin and Sir Edmund Wallcopp. †
Thomas Bushnell, or Bushell, Esq., it is stated by another authority,
was servitor of Lord Chancellor Bacon, and seems to have devoted his life
to mining speculations, being buoyed up with the most sanguine expec-
tations of recovering "mineral riches out of the hardest rocks." In 1658 he
undertook to recover certain drowned and deserted works, being "the forlorn
hope of that great engineer, Sir Bevis Bulmer, at Rowpits, near Churton
minery in the Mendips, upon which it is said £10,000 had been expended
out of Queen Elizabeth's purse to perfect the same, but could not; but at the
moment when Bushell's hopes were about to be realised he was cruelly
thwarted by the malice of certain persons."
In a letter to Charles, Prince of Wales, Mr. Bushell says: “Nothing
doubt but that, in process of time, I shall be able, with the assistance of my
co-adventurers, and help of their greater purse and fortunes, to make these
British hills, as in situation so in esteem too, resemble the West Indies, or
at leastwise, those renowned mines in Saxony."‡
Those mines were for a period exceedingly profitable, and availing him-
self of the indenture of Charles I., dated 30th July, 1647, he established a
mint at Aberystwith. The privilege is granted for the following reasons:
"That there are, and likely to be, many hopeful mines discovered in the
* The whole title is a curiosity. "The Case of Thomas Bushell truly stated, with his progress in
minerals, and the desire of several merchants and others that are ready and willing to advance so good a
work for the benefit of the nation, humbly tendered to the serious consideration of the honourable House
of Commons, and all other persons in authority, whether civil or martial, that are desirous to advance the
trade of the nation, supply the necessities of the poor by discovering the hidden treasures of the earth,
preserve the lives of many poor creatures from untimely death (who are now destroyed in their prisons for
petty felonies) which might otherwise be serviceable to the Commonwealth." London: 1649.
+ William Waller's "Report on the Cardiganshire Mines."
Waller's "Account of the Mines in Cardiganshire.”
154
[BOOK I.
HISTORICAL SKETCH.
principality of the mountains in Wales, where it is conceived are great
quantities of silver, though by reason of the unskilful way of working the
said mines the same are either drowned by water when the ore comes to a
considerable quantity and rich in quality, or that through ignorance the
goodness of the ore is not known to the owner, and so is transported to other
nations for 'potter's ore,'* out of which strangers refine silver, to the great
loss and prejudice of His Majesty's service."
This company made a large outlay; but they failed to raise much ore at
Cwm-symlog, and they never found the lode which was so profitable to Sir
Hugh Middleton. At Goginan, Bushell was more successful, and Mr. Waller
says: "He kept a mint at work at the silver-mill in Cardiganshire, for
the bullion he had at this mine, and is said to have clothed King Charles
the First's whole army from part of his profit in this work." Certain it is
Bushell sacrificed his fortune in the King's defence during the civil wars,
and placed himself at the head of a regiment of miners, which he had raised
in support of the royal cause. Aberystwith Castle was besieged and taken
by the Parliamentary forces, and this led to the mines being abandoned.
Bushell must at one period have been a man of considerable wealth, since
he constructed a harbour at Lundy Island.
In 1658 these mines were visited by Ray,† who thus describes his visit
in his "Itinerary": "September the 6th, I travelled to Mahentler (now
Machynlleth), and then to the silver mills, where I saw and learned the
whole process of the work of melting and refining of silver. They have two
sorts of ore, the one rich, of Dorrens (Darren), and the other poorer, of Taly-
bont. They mix these, six parts of Dorrens with four of the other, because
the former, being rich, will not melt off the hearth without such a quantity
of the latter. Then they carry it in a barrow from the store-house to
each smelter's several bing, where it is melted with black and white coal
(that is, sticks cut into small pieces, then slit and dried).”
In 1662 Ray states: "Thursday, June 3rd, we travelled over the sands, and
so came round about by Talybont, to the silver mills, and viewed the mint at
Talybont, and took as exact a description as we could of the silver works."
After the Restoration the mines again passed into the hands of the
Company of Mine Adventurers. Little appears to have been done at the
mines until about 1667. When Sir John Pettus published his "Fodinæ
Regales," in 1670, they were not worked "effectually," as the knight
tells us.
Pettus gives the following account of the mines at this time:
"A stream of water, three miles from Talybont, falls into four great wheels,
whose turning guides the rising and falling of the bellows and stampers.
At the great stamping-mills there are five hearths, with backs, checks,
work-stones, iron plates, &c.; five pairs of large smelting-bellows, &c., one
great pair of scales with weights." Several other articles are named; and in
the smelting department ten men were employed. The materials in the ore-
house, the old mint-house, the stamping-mills, the refining-mills, the red-lead
mills are then stated, and it appears that in these eleven men were employed.
At the Mines Royal at Talybont four washers, a smith, and a carpenter were
* "Potter's ore" is lead ore free from silver, which is prejudicial, as giving colour to the glazes, &c.,
for which it is used.
† John Ray's "Itinerary," and other works, from 1704 to 1738.
CHAP. V.]
1
CARDIGANSHIRE MINE ADVENTURERS.
155
employed. A list is given showing the number of tubs and sieves, and states
"that four dozen ore-bags lie in the carriers' hands and custody."
In 1670 “Articles of Agreement and Subscription between H.R.H. Prince
Rupert and divers noble and honourable persons and others, undertakers for
working the Mines Royal in the counties of Cardigan and Merioneth, in the
principality of Wales."* From these articles we learn that the undertaking
was to consist of forty shares and no more, of £100 each. The committee
consisted of Sir Paul Neville, knight, Sir Francis Cobb, knight, and seven
other gentlemen, with Mr. Edward Blackwell for treasurer. The committee
was to meet at the Rolls Chamber, in Whitehall, every Tuesday in the
afternoon in term time. They leased from the Mines Royal for one and forty
years "the mines of Comsymlock, Goginan, Cwm-erfin, and Talybont, in
Cardiganshire, and all the mines near Barmouth, in Merionethshire;" and
they also "purchased the lease of the smelting-mills in Skybery Coed, in
the parish of Llanyhangell Generoglyn, in Cardiganshire." The directors
of the company quarrelled, and the mines were neglected.
In 1690 some mines were discovered on the Gogerddan estate, belonging
to Sir Carberry Pryce, who, under an Act of Parliament in the first
year of William and Mary, took in several partners, and “divided his
waste into 4,000 shares." He sent to the North of England, and secured
the assistance of Mr. Waller as his agent at £200 per annum. There arose
an action between the Society of Mines Royal and Sir C. Pryce; the
points in dispute were settled in his favour, but he died without issue, and
Mr. Edward Pryce sold his interest to Sir Humphrey Mackworth for £15,000.
In 1699, Mr. Waller made a report on the condition of the mines, which was
afterwards referred to Sir H. Mackworth and William Player, Esq., of
Gray's Inn. This document shows that about a hundred men were at that
time employed. It does not appear that any large quantity of ore was
raised, but the miners were working upon several veins, which were then
considered to be of great promise. The ore was, at this period, sent
to Neath to be smelted, where Sir H. Mackworth made considerable
improvements in the operations for refining silver and manufacturing
litharge. He also improved the arrangements necessary for loading and
unloading vessels. No effort was neglected which promised to raise these
mines in the estimation of the public. Amongst other methods a long poem
"To Sir Humphrey Mackworth, on the Mines of the late Sir C. Pryse," was
published by Yaldon. The following lines sufficiently indicate the character
of this work :
Thy fam'd inventions, Mackworth, must adorn
The miner's art, and make the best return;
Thy speedy sails and useful engines show
A genius richer than the mines below.
Thousands of slaves unskilled Peru maintains,
The hands that labour still exhaust the gains;
The winds thy slaves, their useful succour join,
Convey thy ore, and labour at the mine;
Instructed by thy arts, a power they find
To vanquish realms where once they lay confined.
The Cardiganshire mines at this period were in a very uncertain state,
but they were in the hands of a mine adventurer who did not scruple to
employ the most exciting means to draw attention to his speculations.
* Printed for William Phillips, at the Black Raven, Chancery Lane, London.
156
[BOOK I.
HISTORICAL SKETCH.
In 1698 arose the novel scheme of the "Mine Adventure," of which a
prospectus, with the following title, was first put forth :-
"The Mine Adventure, or an expedient, First, for composing all differences between the partners of
the mines late of Sir Carberry Pryse; Secondly, for establishing a new method for the management
thereof, and thereby (instead of an arbitrary power over the mines and stock of all the partners in one
person) settling an equal and fair constitution for every person concerned; Thirdly, for granting several
charities out of the same to the poor of every county in England and Wales, without prejudice to
the partners; Fourthly, for enabling the partners to employ a much greater stock therein, and con-
sequently (in the same proportion) to advance the gain and profits thereof; Fifthly, for discharging
all debts, duties, and demands chargeable upon the said mines, originally occasioned by several expensive
law-suits between the said Sir Carberry Pryse and the patentees of royal mines; and, Sixthly, for raising
a large stock of £20,000 (clear of all manner of incumbrances) for the working and carrying on the said
mineral works to the great advantage of the King and kingdom. Proposed by Sir Humphrey Mackworth.
Perused and settled by Eminent and Learned Council in the Law; and finally established in two indentures
made and executed by the present partners, and which shall be enrolled in the High Court of Chancery.'
Such were the high pretensions of those interested in the scheme of the
"Mine Adventure." Mr. Waller, writing at the same period, in the form of a
circular to the people of England, gives the most exaggerated account of the
Cardiganshire mines. "This adventure," says he, "is recommended to the
world as an undertaking whereby not only His Majesty's Customs and the
trade and wealth of England will be advanced by the lead and copper, being
commodities and manufactures of our own country, and thereby the exporta-
tion of our coin and bullion, obtained with so great difficulties from Spanish
Indies, in great measure prevented."
After giving a section of the veins on the estate of Sir Carberry Pryce,
he adds: “And thus you see that there are eight large veins of silver, lead,
and copper ore lying near together in one mountain, where one level serves
to drain the water from all or most of the said veins, and which, it is
presumed, can't be paralleled in any part of the Christian world."
And, again, having set forth the advantages of the situation of these
mines, it is stated: "From all which it plainly appears (by calculation) that,
with a stock of £20,000 and good management, the said mines would yield
a yearly profit, over and above all charges, of £171,970 19s. 9d. for lead,
besides the silver, which is believed will yield, one tun with another, about
£14 in silver per tun of metal, and may, in all probability, double this valua-
tion of the mines. 'Tis plain that this nation can never want silver if these
veins are carried on with a large stock, and will yield such large quantities
of oar at so small an expense as is herein mentioned. This valuation may
seem incredible to many persons not skilled in the art of mining, nor
acquainted with the vast advantages that may be made from mineral works,
especially so large and so well situated near the sea as these are. But if
demonstration will not convince 'tis in vain to use any other argument."
Appended to this account is a rude map of this part of Cardigan, showing
the position of the mines and of the lodes. In an abstract of the accounts
rendered by Mr. Waller to the company in 1700, we have some returns
relative to wages and the expenses of smelting in Wales. A copy of one
of these accounts is given in the accompanying note.*
* An account of the refining 72 tons I qr. 10 lbs. lead, at Neath, from the 16th July, 1699, to 16th
March following, viz.:—
The lead refined, 72 tons I qr. 10 lbs., valued at Neath at £8 per ton
The charge of refining said lead :
£ s. d.
576 2 8
To 120 bushels of bone ashes expended, at 4s. per bushel
To 15 weigh of coals at 205. per weigh
£ s. d.
24 O O
•
15 0 0
Carried forward
· 39 o o
CHAP. V.]
THE COMPANY OF MINE ADVENTURERS.
In the year 1700 the company was regularly formed under the title of
"The Governor and Company of Mine Adventurers in England." The
customs observed at this time appear to have been the same as those of the
present day. It would appear, from a statement made by Mr. Waller, that
they were working upon six veins of lead and two of copper. The following
tabular view was drawn up by Mr. Waller :
Name of Mines. Nature of Ore.
Number of lodes
worked up to this
date.
Number of lodes
known, but not
yet worked.
Depth of Adit or
Level.
Boundary of
silt.
Size of
the lodes.
Assay of ore.
Silver per ton.
Feet.
Miles.
Bwlch-yr-eshirhir
Lead
Silver
3
3
37
14 3
Feet.
4 to 8
Lead
Bwlch-Laninogg
I
I*
Copper
270
Lead
Cwmsumblock
Silver
I
192
2 to 3
2
Lead
Goninian
2
•
Silver
300
Lead
Brinpica
2
Silver
Lead
Cwmervin.
I
Silver
210
54
:
:
Lead
Pencraiddy
I
I
120
Silver
:
44
I}
44
4 in. to 3
44
3 to 5
44
Ysttmuean
Lead
I
5
Cwmystwith
2
New Mines
I
:
:
Brought forward
To wages to workmen as follows:
Paid John Grimshaw, for 21 weeks, at 21s. 6d.
I to 2
(various †
to 1
6 feet
£ s. d. £ s. d. £ s.
22 II 6
39 o o
d.
Samuel Ackroyd, for ditto, at 16s.
•
""
Thomas Humbledon, for ditto, at 10s.
"
William Dalton, for ditto, at 9s.
""
Thomas Forrest, for ditto, at 9s.
""
Michael Parker, for ditto, at 8s.
""
John Jennings, for ditto, at 8s.
16 16 O
IO IO O
•
9 9
""
Robert Reynolds, for ditto, at 75.
Richard Gascoigne, for ditto, at 7s. .
To 428 casks for litharge, at 20d. each
To heading ditto, and nails, 2d. per cask
To seven dozen of candles expended, at 5s. per dozen
8 8
7 7 о
770
35 13 4
2 II 4
I 15 O
100 5 6
9
8
To smith's work, for mending tools
I IO 4
41 10 O
Whole charge of refining said lead
The value of the lead, and charges of refining it
The said lead refined produced 660 ounces of bullion, at 5s. 6d. per ounce
And 74 tons 18 cwt. 2 qrs. 20 lbs. litharge, value at Neath at £io per ton
180 15 -6
756 18
2
IO
181 10 O
749 6 9
930 16 9
By the above account it appears that the bullion and the litharge pro-
duced from the said lead amounts to
930 16 9
That the lead and charges of refining it exceeds not
756 18 2
And consequently there gained by refining the said lead
•
173 18 7
Which is £22 19s. 10d. per cent. clear profit, errors excepted.
* Producing 1 in 5 of fine copper.
THOMAS HORNE.
+ Silver vein, runs in bellies of ore from 4 yards broad to 7 yards, and from 10 yards long to 31 yards,
and from 4 yards high to 7 yards, then connected by leaders of an inch thick for 3 or 16 yards.
157
158
[BOOK I.
HISTORICAL SKETCH.
The quantity of lead raised, notwithstanding all the pretensions of those
with whom the scheme originated, was never large. Mr. Waller furnished
an account, of which the following is a summary:-
The original stock of this company
Leased by building houses for the miners, carriage of ore, stores, and other
incidental charges
Stock in litharge, lead, and silver in the merchants' hands
20,000
6000
5,000
4,000*
In 1709 disputes arose. Sir Humphrey Mackworth and Mr. Waller
quarrelled, and accused each other of unfair dealings. The company dis-
charged Mr. Waller, who petitioned the House of Commons, and a com-
mittee of inquiry was ordered. The result of this was the following:
"Ordered, that a Bill be brought in to prevent the said Sir Humphrey
Mackworth, William Sheres, and Thomas Dykes, their leaving this kingdom,
and their alienating their estates until the end of the next session of Parlia-
ment, and that Mr. Benson, Mr. Arstaby, and Sir Richard How do propose
and bring in the Bill.”
Sir H. Mackworth published a defence of his conduct, and some of
his friends published "A Vindication" as late as 1720. Numerous pam-
phlets and small volumes, written by shareholders and others, were issued
between 1700 and 1737.†
In the library of the British Museum will be found the original manuscript
account-books of this Cardiganshire Mine Adventure and some curious
prospectuses issued by Waller and his partners. From these much of the
information given has been derived.
From the published lists we learn there were 650 shareholders. These
embrace people of every class-peers, bishops, knights, farmers, and humble
shopkeepers. From the list of persons making claims of sums respectively
due to them for stock, bonds, &c. &c., the names below are taken at random
for the purpose of affording some idea of this extraordinary bubble scheme,
which unfortunately finds some examples in our own days. Although a few
* From Mr. Waller's account we learn incidentally that litharge was never made a marketable
commodity in England until Mr. Robert Lydale, the chief operator to this company, patented a process
for its preparation. It was usually sold at £20 per ton, but, from these works it was sold at the price of
red-lead.
†The following is a list of the various pamphlets, &c., published on "The Mine Adventure: "—
"Mine Adventure-Case of the Mine Adventure," folio; "Bill for the Relief of the Mine Adven-
turers," folio; "List of the Adventurers," folio, 1700; "Familiar Discourse, or a Dialogue concerning
the Mine Adventure," 8vo, London, 1701; 8vo, 1705; "Proceedings of the Mine Adventurers,
folio, 1704; “Rules, Orders, &c., of the Company of the Mine Adventurers," 4to, London, 1706;
"Proceedings of the Company of the Mine Adventure in their transactions with Mr. D. Peck," folio,
1707; "List of the Company of Mine Adventurers," folio, 1708; "Proceedings of the General
Court of the Mine Adventurers," folio, 1708; Report of the Committee of the House of Commons
relating to the Mine Adventurers," folio, London, 1710; "List of the Persons who have made a Claim
upon the Company of Mine Adventurers," folio, 1711; "List of the Creditors of the Company of Mine
Adventurers," 4to, London, 1712; "List of the Proprietors of the Company of Mine Adventurers
qualified to Vote," folio, 1727; folio, 1730; "Abstracts of the Present State of the Mines of
Bwlchyr Eskir Hyr," 8vo, London, 1700; "Mine Adventure, Answer to Several Objections against," 8vo,
London, 1737; "Mine Adventure, Settlement of," folio; "Journal of the Mine Adventurers," Stock-
holm, folio, MS.; "Account of the Proceedings of the Mine Adventurers," folio; "Advantage of the
New Scheme of the Mine Adventurers," folio; "Reason for and against the Bill of the Mine
Adventurers," folio; "Remarks on a paper entitled 'Observations on the Bill relating to the Mine Ad-
venturers,' ""folio; "Answer to a Paper published by one Bateman against the Mine Adventure,"
folio; "List of the Governors and Court of Directors of the Company of the Mine Adventurers," 4to;
"Case of the United Creditors of and Proprietors of the Mine Adventure," folio.
CHAP. V.]
PROGRESS OF MINING IN CARDIGANSHIRE.
159
names only are given, the original list, which still exists in the British
Museum, and may be referred to, is a far more extensive one:
The Right Hon. the Earl of Bolingbroke
Rev. Dr. Samuel Blithe.
Thomas Bretton, Esq.
Mrs. Elizabeth Dillingham
The Duke of Leeds
The Hon. Colonel Nassau
Richard Sterne, Esq.
•
•
·
£
700
1,200
3,550
•
1,770
6,440
1,219
14,098
The claims of the various branches of the Mackworth family are
curious :-
Buckley Mackworth, Esq.
Sir Thomas Mackworth
Mrs. Ann Mackworth
Mrs. Mary Mackworth
Herbert Mackworth, Esq.
William Mackworth, Esq.
Sir Humphrey Mackworth.
Kingsmit Mackworth, Esq.
•
•
£
2,037 14
S.
4,335 O
6,663 o
•
6,613
6,656 o
6,510 0
61,740 0
6,530 O
In 1744 the following mines only were working, and in these but few men
were employed: Pencraigddu, Grogwymon, Cwm-ystwyth, and Eurglawdd.
Some of the managers of the Mine Adventure retained, but did not work,
Cyginan, Brin Picca, and Bwlch-cwm-Ervyn; whilst they gave up Esgain-hir,
Talybont, Cwm-symlog, and others. Shortly after this a Flintshire com-
pany worked Darren, belonging to Mr. Griffith, of Pen-y-pont-pern; Ynishir,
Talybont or Galth-y-Crûb, Esgair-hir, Caneinog, Bryn-Llwyd, and Cwm
Sebon, belonging to Mr. T. Price.
In 1751 Mr. Lewis Morris published "A Short History of the Crown
Manor of Creuthyn, in the County of Cardiganshire." We have in that a
long discussion of "Mr. Powell's scheme of converting all the King's com-
mons in Cardiganshire into freeholds in order to deprive his Majesty of his
mines and other royalties in that county." In 1757, and for many years after,
the above Mr. Morris derived a large income from the mines he was then
working.
From this period we cannot obtain any authentic information of the pro-
gress of mining in Cardiganshire until 1810, when Sir Samuel Rush Meyrick
published the following list of the mines then working:
Cwm-symlog, yielding about 40 ounces of silver to every ton of lead.
Darren Vawr, giving 35 ounces of silver to the ton of lead, and 12½ cwt.
of lead from a ton of ore.
Goginan, producing ore of a similar character, which sold at that time for
LII a ton.
Darren Vach.
Cwm Ervyn.
Llanvair.-In 1806 the ore from this mine sold for £27 per ton, containing
from 60 to 80 ounces of silver to the ton of lead.
Mynydd Vach, discovered in 1798, but not then fairly worked.
Escair Vraith, producing principally copper ore, which in the year 1791
sold for £25 per ton.
Ynys Cynvelin.-Lead and copper.
Escair Hir.-In 1806 the ore sold at £18 a ton.
160
[BOOK I.
HISTORICAL SKETCH.
Allt-y-Crúb, worked by a Shrewsbury company.
Llewernog, worked by Sir Thomas Bousalt and by Mr. William Poole,
producing lead ore and sulphuret of zinc.
Ystym Tuen.
Hên Bwlch.
Aur-glawdd.
Moel Góch ore sold in 1806 for £16 per ton.
Pen-y-bauch.
Nant-y-Crier.—Sulphuret of zinc and lead. Lord Powis has a grant of it
from the Crown, and Mr. Sheldon held it of Lord Powis.
Gellaw Erin ore sold in 1806 for £19 per ton.
Rhúr-yr-Agos.—Sulphuret of zinc and lead.
Bron-y-Goch lead ore sold for £18 per ton.
Black Jack, for £4 10s. per ton.
Llwng Wnwch.
Grogwnion.
Log-y-Lás.—A level was begun about 1790.
Escair-y-Min.-In 1751 three workmen took a year's lease of Mr. Morris,
and in that time cleared £1,300 each. Lord Powis has a grant of it from the
Crown.
Cwm-ystwyth.
Nant-y-Meirch.-Sulphuret of zinc, which in 1806 was sold for £5 10s.
per ton.
Cwm-yr-Anner ddû, Nant-y-Cagl, Pen-y-fordd Goch, and Pen-y-sarn, not
worked.
Bhysgog.
Escair-gad-vach, Cwm-trinant, Tan-y-gaer, Bach-ddû, producing very
small quantities of ore.
These brief notices will, it is hoped, afford a general view of the progress
of mining industry in Cardiganshire up to 1810.
STAFFORDSHIRE.-The copper ore has been already described. The
lead ores of this county appear to belong to this place. Plot says of the
lead ores, "They cannot be said to be earths. Lead is dug here in à
yellowish stone, with cawk and spar in Fown's field, belonging to one
Townley, on the side of Lawton Park, where the workmen distinguish it
into three sorts, viz. round ore, small ore, and smithum; the two last whereof
are first beaten to pieces with an instrument called a knocking-bucker,
and the ore separated from the stone with another, called a limp, and then
washt with a seive made with iron wyre, yet further to clear it from ter-
restrieties, which done it is sold to the potters at Burslem from £6 to £7 a
ton, who have occasion for most that is found here for glazing their pots.
There has been lead ore dug also at Ecton Hill, where some of it lies
so near the day that it was first found by the plough. Here also they dis-
tinguish it into three sorts, but under different names from the former, the
best being bing, the middle sort bowse, and the lead-dust smithum; and
there was lead ore dug formerly by the Right Honourable the Earl of Shrews-
bury at Ribden. But none of these works were ever very considerable, nor
is it likely any such should ever be found here, it being observed that wherever
CHAP. V.]
LEAD MINES IN LANCASHIRE.
161
there is much coal, there is so much the less lead, its sulphureous spirit being
too strong for the production of that metal; upon which account, when near
Mendip there was found two or three hundredweight of very good lead
ore growing to a vein of coal, it was looked upon by all as a very great
rarity."*
LANCASHIRE, YORKSHIRE, AND CHESHIRE.—A green carbonate of copper
is stated to have been discovered by Mr. W. Marshall in the Magnesian
Limestone at Newton Kyme, near Tadcaster. The copper runs through the
Limestone in thin veins, dipping considerably to the west, which is also the
dip of the Limestone itself. That copper has been of frequent occurrence in
this quarry is proved by the débris and the copper-stains on stones built
into the old walls about Newton Kyme. The Coniston mine, on the banks
of the lake of that name, has proved a good copper mine; and this ore has
been found at Merrybent, near Melsonby. These will be properly noticed in
a future chapter.
At Farnham, two miles north-west of Knaresborough, in the Magnesian
Limestone, copper is said to have been obtained in small masses, and a
considerable quantity is said to have been formerly obtained by means of
galleries worked through the Limestone. The workings were abandoned and
the shafts filled up, owing to the quantity of water accumulating, which the
rude engines of the time, worked by horses, could not overcome.
A small quantity was found in 1805, upon sinking a well through the
Limestone at Farnham.†
Charles Leigh, Doctor of Physic, 1700: "The metals of those countries
are lead, iron, copper; the Metallis affinia, or bodies betwixt metals and
minerals, are antimony, black lead, and Lapis calaminaris. Lead ore is
frequently found either in spars, white sand in the fissures either of lime-
stone or freestone, and then it runs in veins, as the workmen call it.
These are of different sizes, sometimes the mine being a quarter of a yard
in diameter, and the same mine sometimes not above an inch, and a little
after, the rock clasping together, the veins entirely disappear, through which,
the miners, continuing to work, recover the vein of metal as formerly.
There are four kinds of lead ore, viz. the spar ore, coke ore, potter's
ore, and white ore. The spar and coke ore are about equal value, and are
fluxed with white wood in furnaces for that purpose, and they usually run
about a fourth or fifth. Potter's ore will not lose above a seventh, and fre-
quently contains a portion of silver. The white ore is a natural ceruss, and
yields a greater quantity of metal than any of the rest."+
"Near Chorley, twenty-five miles north of Wigan, are lead mines, not now
worked, belonging to Sir F. Standish. These mines, which produced the
witherite, or ærated barytes, were sunk in the grit or sandstone; they ceased
to be worked fifteen years since (¿.e. 1787), and are now filled up by the earth
running in, or are full of water” (Mawe).
"To the west of Lankester is Ulverston, remarkable for iron mines of rich
hæmatites. One perpendicular vein of ore is thirty yards wide, in limestone.
* "The Natural History of Staffordshire." By Robert Plot, LL.D. 1686.
† Wm. Marshall, Esq., “Notice of Carbonate of Copper occurring in the Magnesian Limestone at
Newton Kyme, near Tadcaster." ("Geological Transactions," Second Series, vol. ii. p. 140.)
"Natural History of Lancashire, Cheshire, and the Peak, in Derbyshire."
M
162
[BOOK I.
HISTORICAL SKETCH.
Large nodules, some even weighing 4 cwt., of a kidney form, metallic lustre,
and stellated fracture, are found in the loose earth" (Mawe).
At Alderley Edge is a very remarkable deposit in the sandstone, of
copper and lead. The existence of scoria in the ploughed field, to which my
attention was called by Lord Stanley of Alderley, proved that smelting
operations had formerly been carried on here. It is stated that cobalt having
been found in this sandstone, a Liverpool man established works for the
production of smalts, and made much money by the process. He was
eventually stopped by the authorities, who established their position, and the
heavy surcharge for making glass without a licence was his ruin.
ISLE OF MAN.-Evidences of mining operations carried on at a very
early date have been noticed at Brada lead mine, in the south of the Isle of
Man.
John Comyn, Earl of Buchan, obtained from Edward I. a licence to dig
for lead in the Calf of Man to cover eight towers of his Castle of Cruggleton,
in Galloway.*
In the course of the period from the fifteenth century to the seventeenth,
the family of Stanley sought for copper in the Isle of Man, and some traces
of their workings can still be found. The ore discovered was not abundant,
but of good quality, producing six pennyweights of copper per ounce of ore.
In the Statute Book of the Isle of Man various notices of mining opera-
tions occur under the dates A.D. 1422, 1613, 1618, 1630.
Bishop Wilson, in his "History of the Isle of Man," expresses his belief
that mines have been wrought in the island from a very early period. What
this means it is impossible to say. Mention is made of mines in the Isle of
Man in the time of Sir Stanley, appointed King of Man, by grant from King
Henry IV., in the year 1407. Mr. Fitz-Simmons says that the mines at
Brada, he believes, were the first opened; whether those at Foxdale were then
opened may be doubted. The Laxey mines were worked by a Cumberland
company about the commencement of the eighteenth century.
Mr. William Scott, of Douglas, thinks that the mines at Brada were
wrought previously to the discovery of gunpowder, from "feather wedges.
having been found in the levels.
66
Mr. William Geneste informed Dr. Berger that he found in some book,
Charge of the Revenue," in the Seneschal office in Douglas, "that the last
Earl of Derby had the mines wrought, paying the workmen at the rate of
£3 Manx per ton for the lead ore raised. In the year 1709 he paid the
miners for seventy tons; from the years 1709 to 1713 about thirty tons yearly.
A new smelting-house was built in the year 1711. The working of the
mines was totally suspended about three years ago."
SCOTLAND.—In the records of mining in this kingdom we find numerous
licences, amongst others the following:-
1562.-John Acheson and John Aslowan to mine for lead.
1565.-Johnne Stewart, of Farlair and his sonn, "licence to wynt and
transport all and sindry kyndes of metallick uris."
1565.—August 26th, the Earl of Athol, regarding the workes of the mines
of Glengonar and Wanloch.
*"The Isle of Man." By the Rev. Joseph George Cumming, M.A. 1847.
CHAP. V.]
SILVER MINES IN SCOTLAND.
163
1565.-Contract between the king and queen and several burgesses of
Edinburgh for the mining of 40,000 stones of lead ore. 31st Oct. 1565.
In 1586, George Douglas, of Parkhead, had a grant of mines in the lead-
hill district. He was accidentally killed by a landslip, and when his body
was found "he had good store of gold above him."
1592, 8th June.-Memorial anent the metals for the laird of Merchant-
stonnis. This relates to sundry mines, and among others, "Item, imprimis
the copper mynd in Vyndloch had he wrocht at thre quarteris of an yeir and
xii. men." The second, "The leed myne in Glengoner water which he wroch
at by the space of three years: sum tyme xxiii., sum tym xxx., sum tym xxxvi.
men."
1153.-Henry, Archbishop of York, made complaint at Carlisle, to King
David, on account of his forest, which the King's men who worked in a Silver
mine, wasted.* This is quoted from J prior Hagustal, c. 288. Ritson states
that, after David had conquered Northumberland and Cumberland, it was
agreed between him and Stephen "that Northumberland should be yielded
to king Stephen, and Cumberland remained to king David.”
In 1620 Sir Thomas Menzies, provost of Aberdeen, went to London "with
specimens of silver ore found in Sutherland, which were very rich, but as he
died without disclosing what part of the shire they were found in, the mine
has still to be discovered."+
Between 1710 and 1715 Sir John Erskine of Alva discovered a valuable
vein of silver between Middlehill and Woodhill, in the Ochills. This was so
rich that 14 ounces of ore produced 12 ounces of silver, and for a short period
the proceeds of the mine were stated at £4,000 per week. In 1767 Lord Alva
presented to the church of Alva a pair of communion cups on which the
following inscription is engraved: "Sacris in ecclesia S. Servani apud aleth
A.D. 1767, ex argento indigena D.D.C. q Jacobus Erskine." ‡
Between 1585 and 1590, says a document from the Balcarres MSS., 15,717
stone weight of lead obtained in Lanarkshire was shipped for foreign use.
From a charge against the laird of Merchiston, it would appear that
before this, a large trade was carried on from Leith.
In 1593, Thomas Foulis "had got a tack of all the mines in the sheriff-
dom of Lanark. In 1597 the trade from the Lanarkshire mines had much
increased. Foulis died about 1611."§
In 1641 the mines in Waterhead and Glengonar were granted to Sir
James Hope, of Hopetown, and in 1649 an Act of Parliament was passed to
protect the lead mines and miners.
In 1661 Sir James Hope obtained a long Act, ratifying former grants. At
that period not only did the family possess the original lead mines in Craw-
ford Moor, but also the copper mines in Aithray, and the silver mines called
the Binnie Mines.
In 1606 silver was discovered in considerable quantity at Hilderston, in
Linlithgowshire, on the property of Sir Thomas Hamilton, of Binnie. "Sir
Bevis Bulmer hath sett downe in his booke the manner how the rich silver
* "Annals of the Caledonians." Joseph Ritson. W. & D. Laing, Edinbro'. 1828.
† Sir Robert Gordon's "History of the Earldom of Sutherland.'
"Old Statistical Account of Scotland,” vol. xii.; Nimmo's "History of Stirlingshire."
Irving's "Upper Ward of Lanarkshire."
M 2
164
[BOOK I.
HISTORICAL SKETCH.
mynes at Hilderstone, in Scotland, were found, and how they were lost, &c.
Now concerning the finding thereof, Sir Bevis saith in his booke that it was
found out by meare fortune or chance of a collier, by name Sandy Maund, a
Scotsman, as he sought about the skirts of those hills neare the bourne or
water of Hilderstone. And this Scotsman, by means of digging the ground,
hitt upon the heavy piece of redd-mettle; no man thereabout ever saw the
like. It was raced with many small stringes like unto hairs or thredds.
It had descended from a vaine thereof, where it had engendered with the
sparr-stone, which sparr-stone in forraine provinces is called by other tra-
vellers Cacilla. And he sought further into the ground, and found a piece
of brownish sparr-stone, and it was mossie. He broke it with his mattocke,
and it was white, and glittered like unto small white copper-keese" (copperas,
or sulphate of iron, probably the arsenial sulphide, as recently cobalt
has been discovered in this mine), "which is to be found in many common.
freestones. And he never dreamed of any silver to be in that stone, and
he showed it to some of his friends, and they said, 'Where hadst thou it?'
Quoth he, 'At the silver bourne under the hill called Kerne-Popple.' Where-
upon a gent of Lythcoo (Linlithgow) wished Sandy Maund to travaille into
the Lead Hill, and about Glangowner Water he should hear of one Sir Bevil
Bulmer, and said, 'If it prove good he will be thankful, if otherwise he will
reward thee, and I will send to him by letter."" There is much more of the
same uncertain character. A specimen is obtained and sent to Mr. Atkin-
son, of Foster Lane, London, and "he tryed and recommended it above all
others that ever they saw before."
The Earl of Salisbury was consulted by Mr. Atkinson, and the Earl said:
“A more curious piece of work in a stone (viz. in a menerall or minerals
stone) no man hath ever seen, which I esteem above all others, because of
Scotland, from whence I have had sundry times gold, but never anything of
this sort as perfect silver.” . . . Atkinson thus describes the mineral:
"The manner how it grew was like unto the hair of a man's head, and the
grass in the fields, and the vaine thereof out of which I had it was once two
inches thicke, by measure and rule, the mettle thereof was both malliable
and toufe. It was coarse silver, worth 4s. vi.d. the ounce weight, not fine
silver, as is made by the art of man. The greatest quantity of silver that
ever was gotten of 'God's Blessing (the name given to the mine) "was
raised and fined out of the red mettle, and the purest sort thereof; this con-
teyned in it 24 ounces of fine silver upon every hundred weight, vallewed at
vi. score pounds sterling the ton, and much of the same redd-mettle by the
assay, held twelve score pounds sterling per ton weight. . . . And when I
wrought on the first sorte redd mettle for Mr. Bulmer and my Lord Advocate
of Scotland sundry times I refined, and commonly for the space of three
days weekly I made an hundred (pounds) sterling each day, &c. Some part
of the redd-mettle was brought to London to be tryed, and small profit arose
thereof, and scantily it paid charges thereof, for the blessing of God was
extracted by God's providence before.”
Lord Menmuir (Mr. John Lindsay, of Drumcair) was promoted to the
bench in 1581. He married Dame Marion Guthrie, granddaughter of Sir
William of Lunen, &c.
CHAP. V.]
MASTER OF METALS IN SCOTLAND.
165
Lead mines, supposed to be of great value, were discovered in Glenesk,
and rocks of alabaster, excellent, as it was asserted, for lime; and Lord Men-
muir, whose attention had already been directed to mining, with a view to
the improvement of the public revenue, entered eagerly into the project of
working them. Workmen were procured from Germany, smelting-furnaces
built, and large sums expended; and how sanguine their first hopes were,
and with what zeal the enterprise was begun at last, after several ineffectual
commencements, the following letter will show. It was carried to Edzell by
a German engaged by Lord Menmuir for the business:-
"RIGHT HONOURABLE SIR AND BRODER-
"Efter heartly commendations of service, please wit I have chosen
ane metal-man, very metal-like, and hes sent him to you as maist necessar
for mony affairs. He can burn lime, and says the grey stane at Invermark,
beside the lead eur, whilk also he effirms to be lead eur, is a lime stane. He
can make charcoal of peats, and will desire na other fuel, either to burn lime
or melt copper. He is perfyt in kenning of ground and discovering of metals.
He can essay the little essay, and melt in great, and will learn Andro Daw
and all your folks. He offers for ten pounds sterling to big you a miln (build
you a mill), whilk will serve for melting of copper and lead, and making of
iron, whilk also he can make perfectly; and says, gif ye will get him a seam
bot three fingers braid of your copper, he shall pay himself all his yearly
wages, and get you two hundred pounds sterling of yearly profit, whilk will
extend to mair nor nineteen hundred pounds Scots. He will promise to
tarry for a year with you, providing he be thankfully payit of three pounds
twelve shillings in the ouk (week), whilk is eight shillings less nor the twa
Dutchmen whilk we had before, and that he be oukly (weekly) avancit. He
will given you down twelve shillings of his oukly wages gif ye will furnish to
himself and his wife a house and fire, whilk I think best, for it will be easy
to you, and hald you in sa mickle silver oukly. He has a very guid conceit
of your eur, and says Thomas Foulis' folks hes cassin (cast) away over meikle
thereof, and desires na better nor (than) he hes cassin away. With these
foresaid guid qualities ye mon (must) understand he hes a bee ('He has a bee
in his bonnet,' Scotch proverb), as mony guid craftsmen hes, and is fickle,
and gif he be not weill handlit and payit, he will slip away, as he hes done
presently fra Thomas Fowlis' wark. Yet I have gotten Thomas his consent.
I fear your forgetfulness in payment, and in appointing his house and fire,
and in causing him be furnishit upon his awin expences, therefore divert all
thir things to your carline (meaning literally 'old wife'). Farder, the Earl
of Argyle has written earnestly to you to be in Glasgow the second of April
next at a solemn convention of his friends, wherein ye maun not disobey his
lordship's request, otherways he will think him far disappointit, now when
he hes maist ado. I will (if) able keep the tryst myself. It will be but three
days' riding to the compass. Sa God preserve you!
"From Edinburgh, the 9th of March [1593-4].
"Your broder at service,
"MR. JOHN LYNDESAY."
166
[BOOK I.
HISTORICAL SKETCH.
"P.S.-This Dutchman says your alabaster will be excellent white
plaster. They call him Bernard Fechtenburg. He hes meikle English that
your carline will understand him weill aneuch."
That same year (1592) the King created and granted Lord Menmuir, for
life, the office of "Master of the Metals and Minerals" within the kingdom,
knowing the qualification," says his Majesty, "of his weile beloved Coun-
cillor, and his traveles in seeking out and discovering divers metals of
great valuer within this realm, and in sending to England, Germany, and
Denmark to get the perfit assay and knowledge thereof."
Lord Lindsay says: "I cannot exactly say how these speculations turned
out, but papers and plans without end relating to them survive in the
family repositories.”*
SUTHERLAND.-"An essay of the silver mines was carried to London in
1620 by Sir Thomas Menzies, Provost of Aberdeen, and, being tried, it was
found very rich in silver."
ORKNEY ISLANDS.-Mr. Ganiel, the German chemist, "hath an hundred
several lead ores from the Orkney Islands."
"As to the metals contained in the bowels of this country, it is affirmed
that different kinds of them are to be found in the valley of North Esk. The
great-grandfather of the present proprietor of Edzell (that is, Sir David of
Edzell, with whom we are now occupied) discovered a mine of iron at the
wood of Dalbog. This gentleman's grandson (John L. of Edzell) found some
lead ore near Invermark. The son of this latter (David, the penultimate
laird) found a very rich mine of lead on the banks of the Mark, about a
mile up the valley from the castle of Innermark." †
IRELAND.—Mr. John Taylor, in the "Transactions of the Geological
Society of Dublin," states that when Messrs. Colpoys and O'Callaghan
opened the Milltown lead mine, in the county of Clare, "the ancient
workings were now completely cleared, and some rude tools discovered,
such as oaken shovels and iron picks, the latter of extraordinary size and
weight; also the remains of fires, which had evidently been made use of to
crack and loosen the masses of calcareous spar and carbonate of lime, in
which the ore of this mine is chiefly imbedded.”
*The most curious of these is a contract dated 12th October, 1602, betwixt Sir David and his
eldest son on the one side, and Hans Ziegler, citizen of Nuremberg, in the country of High Germany, on
the other," by which the former "sets and grants to him and his companions all the minds (mines)
of gold, silver, quicksilver, copper, tin, and lead, and of all other minerals (except iron and marmor)
within all the bounds of
the barony of Edzell and Glenesk," with right of building houses,
furnaces, cutting wood, &c., for twenty-five years, the return being "to thankfully pay and deliver, &c.,
the fith part of all and sundry the said metals of gold, silver, &c., whilks the said Hans, his partners, &c.,
shall happen to dig, holk, work, and win out of the said minds," &c. &c. Sir David further granting
them "the power to big and erect towns and burghs beside the said mines, to create baillies, officears,
and other members within the samyn, to hold courts, and to do justice thereintil for the space of twenty-
five years."
+ Edwards's "Description of Angus," 1678.
CHAPTER VI.
GOLD, PLUMBAGO, IRON ORE, AND SUNDRIES.-TO THE END OF THE
EIGHTEENTH CENTURY.
THAT the Britons collected gold from the tin streams of Cornwall and
Devon appears certain. That the tin streams were at one time rich in
gold is highly probable, and if the inhabitants searched those streams for
tin, they would be certain to discover the gold. Cæsar states in his "Com-
mentaries," that one reason for his invading the Britons was, because they
assisted the Gauls with their treasures, with which their country did abound.
Samuel R. Meyrick* speculates on the probability that the Britons wrought
at a very early date the mines in Cardiganshire for gold.
It is curious to find, again and again, reports of the discovery of gold in
these islands. Sir J. Pettus, in his "Fodinæ Regales," says, "Cimboline,
Prince of the Trinobantes (wherein Essex is included), who had lived much
at Rome in Augustus' time, was seated at Walden in that county, and
did (according to the Roman way) coin monie instead of rings, which might
be from that mine which was afterwards discovered in Henry IV. his time in
that countie." There is not existing any account of the discovery of such a
gold mine. But Henry IV., by his letter of Mandamus (11 May, Anno 2,
Rol. 34), commands Walter Fitz-Walter (upon information of a concealed
mine of gold in Essex) to apprehend all such persons as he in his judgment
thinks fit, that do conceal the said mine, and to bring them before the King
and his Council, there to receive what shall be thought fit to be ordered.
CORNWALL. Of the existence of gold in Cornwall we have the following
intimation by Carew t:-"Tinners do also find little hopps of gold amongst
their ore, which they keep in quills, and sell to the goldsmiths, oftentimes
with very little better gain than Glaucus' exchange."
Tonkin, in a note, says: "We have not only Mr. Carew's authority, but
likewise in the 'Bailiff of Blackmore,' written by one Mr. Beare, in
Queen Elizabeth's time, we have an account of a gentleman that, at a wash
of tin at Castle Park, by Lostwithiel, took out of the heap of tin certain
glorious corns (which they call rux) which he affirmed to be pure gold, and
at the same time 'shewed a gold ring made of certain gold hopps, which he
had gathered among the tin corns at a wash in a stream works, together
with another gold ring, each of 16s. 6d. value.'" He tells us of two pieces of
* ( History and Antiquities of Cardiganshire." By Samuel Rush Meyrick. 1810.
Carew's "Survey of Cornwall, with Notes." By Thomas Tonkin, Esq. Published by Francis, Lord
De Dunstanville, 1811.
Ի
168
[BOOK I.
HISTORICAL SKETCH.
tin containing gold; that Mr. Boyd imagined that gold might be extracted
from tin; that Mr. William Glynn, of Glynn, had a gold seal-ring made
of gold hopps found in the river Fowey; and of one Christopher Kirkly,
who was sent down in the latter end of the reign of King Charles II. to
make experiments in separating gold.
Borlase mentions that in 1753 some men streaming for tin in St. Stephen's
Bramel, found gold so plentifully mingled with tin that the smelter took it
for mundic; but the tinners made much money from this find. Borlase also
states that gold has been found in the parishes of St. Ewe, Creed, St.
Stephen's, St. Mewan, Probus, Kenwyn, and other places. The largest
piece he had seen was found in Creed in 1756, and weighed 15 dwts. 3 grs.
Sir Christopher Hawkins notices the mixture of gold and tin in Ladock
Stream Works. Several pieces have been found in Carnon Stream, at the
head of Restronget Creek, in the Falmouth estuary. Several fine specimens
of gold found in Cornwall are in the collection of the late John Michael
Williams, at Scorrier. Gold has been found in the tin streams of Dart-
moor and in the hæmatite iron ore of the Poltimore and the Bamfylde mines
near North Molton, specimens having been in the collection of R. W. Fox,
Esq., at Falmouth.
WALES.-Of the Ogofau gold mine Professor W. W. Smyth has given the
following account: "Antiquaries have long had their attention directed to the
ancient mine-workings at Gogofau, or Ogofau, near Pumpsant, Caermarthen-
shire. These works were undoubtedly commenced by the Romans. The
remains of Roman pottery, ornaments, and a bath, affords reason, Mr. Johnes
(the proprietor) considers, for presuming that there was a Roman station near
this spot connected with the mines. Several gold ornaments have been dis-
covered, and a beautifully-wrought golden necklace is now (1846) in the
possession of Mrs. Johnes. The name of the parish, Conwile Gaio, tends also,
Mr. Johnes remarks, to the conclusion, that the Romans occupied this
ground, provided the interpretation given to it be correct, for Conwile Gaio
is supposed to signify "the advanced post of the Romans."
"It has been a matter of surprise with those who visited the Ogofau that
iron pyrites was the only ore visible, and that large heaps of apparently pure
quartz, carefully broken to the size of a common nut, were alone found. The
Geological Survey discovered, however, a specimen of fine gold in the quartz
of one of the lodes, and thus corroborated the evidence which tended to
prove that the mines were worked for gold."
The majority of the workings, extending a considerable depth for some
acres across the side of the hill, are open to day, or worked, as usual in
the early days of mining, like a quarry; and the rock through which the
lodes run, a portion of the lower Silurian rocks, is in many places exposed,
and exhibits beds much contorted and broken, though having a general
tendency to dip northward. Here and there a sort of cave has been opened
upon some of the quartz veins, and in some cases has been pushed on as a
gallery, of the dimensions of the larger levels of the present day, viz. six or
seven feet high, five or six feet wide, and amongst these two of the most
remarkable are kept clear by Mr. Johnes, and being easily accessible, allow
of close examination.
CHAP. VI.]
GOLD IN THE BRITISH ISLES.
169
The upper surface of the hill is at this, the south-eastern extremity of
the workings, deeply marked by a pinch running N.E. and S.W., similar to
the excavations technically called open-casts, where the upper portions of
the lodes were, in early times, worked away; and when it was afterwards
found disadvantageous to pursue the lode in this manner, a more energetic
and experienced mind must have suggested the plan of driving adit levels
from the north face of the hill through the barren rock, in order to cut the
lode at a greater depth than it could otherwise be reached, and the perse-
verance exhibited in driving 170 feet through the slate in each of the levels
in question, was no doubt based on a sufficient knowledge of the continuous
nature of a mineral lode.
The upper level communicates with the trench on the surface of a rise on
the lode, and with the lower level by a passage of some few feet in length,
through which it is barely possible to creep, and then by workings from
which a considerable quantity of matter has been removed.
The veins, or lodes of quartz, vary many degrees in their line of direction,
and dip at angles of from 28° to 80°, some to the S.E., others to the N.W.,
and their width varies from an inch to a foot. Mr. Smyth carefully described
the character of the quartz, and gives a drawing of a rock upon which he
believes the Romans reduced it to powder. He continues, "In considering
the proofs of the Roman origin of these works, one of the most remarkable
points is the large size of the levels, whilst we know that the galleries of
mines for some centuries previous to the general application of gunpowder
in blasting were made so small as to render it very painful to walk through
them for an hour or two. Examples of these are frequent in the older mines
of Cornwall, and still more so on the continent of Europe; nor till we
go back to the time of the Romans have we anything by which we can
compare the Ogofau, but in the extraordinary hill called Csetate, or fortress,
at Verespatal, in Transylvania.
,, *
A sentence from Cicero has often been quoted to prove that the Romans
imagined there was no silver in Britain; but Tacitus, in his "Life of
Agricola," expressly states the occurrence both of gold and silver: "Fert
Britannia aurum et argentum et alia metalla, pretium victoriæ."
The recent discovery of gold in Merionethshire will form the subject of
future consideration. We, however, draw attention to the reputed discovery
of gold in various parts of Scotland.
SCOTLAND. It is the general opinion of archaeologists † that the gold
ornaments of the prehistoric ages were made of native metal. The first
historical notice of gold occurring in this country is the grant of David I. to
the Abbey of Dunfermline in 1153 of a tithe of all gold which should accrue
to him from Fife and Fothrif. Gilbert de Moravia is said to have dis-
covered gold in Duriness, in Sutherlandshire, in 1245.§ The Scottish
Parliament granted to the Crown, in 1424, all the gold mines in Scotland,
and also all silver mines in which three-halfpennies of silver could be
*W. W. Smyth, "Note on the Gogofau or Ogofau Mine, near Pumpsant, Caermarthenshire."
("Memoirs of the Geological Survey of Great Britain," vol. i. 1846.)
+"Early Records relating to Mining in Scotland." Collected by R. W. Cochrane-Patrick, of
Woodside.
Regist. de Dunfermelin," p. 16; "Haile's Annals" (1819).
"Genealogical History of the Earldom of Sutherland." By Sir A. Gorm. 1813.
170
[BOOK I.
HISTORICAL SKETCH.
fined out of a pound of lead. James II. granted certain lands to the
Carthusians of Perth, and the charter expressly conveyed all metals of
every sort.*
During the reign of James IV. the gold mines in Crawford Moor were
first discovered.† In the treasurer's account for 1511, 1512, and 1513, there
are numerous payments to Sir James Pettigrew for working the gold mines
there. There are also sums entered as wages to Sebald Northberge, the
master finer, Andrew Ireland, finer, and Gerard Essemer, the melter.‡
About 1683 some gold must have been found, as a gold medal struck to
commemorate the coronation of Charles I. in Scotland bears round the edge,
EX AVRO VT IN SCOTIA REPERITVR.§
From that time until very recently no considerable attempt to find gold
was made in Scotland.
In 1513 John Damione, Abbot of Tungland, received a sum of money
from the King to visit the mines on Crawford Moor.|| In 1515 the Queen
regent again commenced mining, and paid to the "Lord Postulate of the
Yles for to pass to Crawford Moor, and there to sett workmen and mek
ordinances for the gold mine." ¶ Sir Robert Sibbald and Colonel Broth-
wick say they "have seen pieces as big as a cherry; it is exceeding fine
gold," and they name four other places where gold has been found. In
1524** the Albany medal was made from gold found in Crawford Moor, and
much of the gold coinage of the reign of James V. was minted of native
metal.†† In 1526 a lease was granted to Joachim Hochstetter, Quintin de
Lawitz, Gerard Sterk, Antony de Nikets and other Germans and Dutch-
men, of all the mines of gold, silver, and other metals for the space
of forty-three years, which was confirmed by Parliament. In the follow-
ing year a contract was made with Hochstetter and his partners to
coin gold and silver money for ten years.§§ In 1535 a commission was
appointed to inquire into the working of the mines, and in 1539 miners from
Lorraine were sent to Scotland to work the mines on behalf of the King.
They were placed under the charge of a goldsmith, John Mossman, and it
appears between 1538 and 1542, 41 ounces of native gold were used in
making a crown for the King and 35 ounces for a crown for the Queen,
17 ounces for the King's great chain, and a belt for the Queen weighing
19 ounces.|||| In 1565 John Stewart, of Tarlair, and his son William, were
granted the privilege of working any mines of gold and silver not pre-
viously known, they agreeing to bring the gold to the mint at ten pounds
the ounce and fine silver twenty-four shillings the ounce.
of of
Beyond this there was a large coinage of gold bonnet-pieces, and for
*"Acts of Parliament of Scotland" (Record edition), vol. ii. p. 65.
+ Lesley's "De Origine," &c., Scotorum (1675).
Chambers's "Caledonia," vol. iii. p. 733.
Pinkerton's "Metallic History," No. 99.
History MSS. Commission." Fourth Report.
9 Irving's "Upper Ward of Lanarkshire.”
**“Numismatic Chronicle" (1877)—" Records of Coinage of Scotland,” vol. i. p. 54.
++"Record of Coinage.
اركو
"Acts of Parliament, Scotland," vol. ii. p. 310.
"Record of Coinage of Scotland," vol. i. p. 64.
Irving's "Upper Ward of Lanarkshire," vol. i. p. 53.
CHAP. VI.]
GOLD IN SCOTLAND.
171
special ornaments, all the gold, it appears, having been obtained from
Crawford and other moors.
*
Some of the early coins of Mary's reign were of native gold. In 1567,
Cornelius de Vois, a Dutchman, obtained a licence from the Regent Murray
to work gold and silver for nineteen years in any part of Scotland. Several
other grants were made, and six score hands were employed in the summer
months in searching and washing, the gold found being taken to the mint
at Edinburgh to be coined into twenty-pound Scots gold pieces.*
On
one occasion De Vois sent eight pounds of gold to the mint within thirty
days. Arnold von Bronchworst worked the mines subsequently for the
Regent Morton. In 1576 Abraham Potterson, a Dutchman, was licensed
to work the gold, silver, and lead mines in Scotland for twelve years,
except the lead mines of Glengonar and Orkney, which were granted to
George Douglas and others. Potterson was to pay six ounces out of every
hundred of gold and silver. The miners of Crawford Moor, of Robertmoor,
and Hinderland, were prohibited from exporting any gold out of the realm.†
A grant of all the mines and minerals in the country was given, in 1583,
to one Eustachius Roche, who had some political mission at the Scottish
Court, to search anywhere for minerals, and to use the timber of the royal
forests, certain mines belonging to the Earl of Arran being specially
exempted.‡
<<
About 1578, Bevis Bulmer, an "ingenious gentleman," was engaged by
a goldsmith in Edinburgh, Thomas Foullis, to work his lead mines in
Lanark. Bulmer appears to have sought zealously for the quartz veins from
which the stream gold had been derived, but he was not successful. Two
large nuggets are recorded to have been found by him, one weighing six
ounces and the other more than five ounces, of pure gold. A piece of
sapper stone" (probably part of a quartz lode) was found at Long-Cleugh
Head, weighing two pounds, from which an ounce of gold was taken.
Bulmer erected a stamping-mill, and succeeded in getting much "mealy
gold." He appears to have worked chiefly in Mannock Moor, Wanlock
Water, in Nithsdale, in Friar's Moor, Crawford Moor, and the district of the
Lead Hills.§ He is said to have been most successful in Hinderland Moor,
in Ettrick Forest, which gave him large quantities of gold, "the like of it in
no other place in Scotland." He presented a porringer of native Scottish
gold to Queen Elizabeth, on which was engraved-
I dare not give, nor yet present,
But render part of that's thy own:
My mind and heart shall still invent
To seek out treasures yet unknown.
* "Records of Coinage of Scotland."
+ Thorpe's "Collection of State Papers" (1509-1603).
Irving's "Lanarkshire."
In addition to these we have the following :-
"Ane Memorandum left by Robert Seton, commonly designed of Mexico, anent the metals in
Scotland, especially gold." He gives the names of forty places where more or less gold was found.
Many of these were very doubtful.
Another Memorandum of the Minerals in Scotland, communicated to Sir Robert Sibbald, by
Colonel Borthwick, 1683. (a) Gold is said to have been found at Dunideer, near Aberdeen; in the bogs
of New Leslie, two miles from Dunideer; at Overhill, belonging to Lord Glamis; at Glenclought.
(b) Silver mines were worked at South Farrin, at Menzies, ten miles north of Aberdeen; and another near
Disblain, eight miles from Aberdeen.
172
[BOOK I.
HISTORICAL SKETCH.
George Bowes, in 1603, received a grant of £200 to be "employed about
the mines of gold in Scotland," and immediately afterwards another sum of
£300 to work for certain minerals in Wanlock Water. In 1604 the Privy
Council of Scotland issued a proclamation prohibiting any one from molest-
ing or troubling Sir Bevis Bulmer in his search for metals. Numerous letters
from George Bowes are published in the "Early Records of Mining in Scot-
land,” but he can scarcely be said to have been successful, although he found
gold in many places.
From Atkinson's account of the gold mines of Scotland, we learn
that "Mr. Bowes, who works sundry mines on Robbart's Moor at
Wanlock Head, in the reign of Elizabeth, was killed in the copper mines
at Keswick.
"And he went home richly into the north country where he dwelt, (but)
unfortunately, in riding to see the copper workes and mines in Cumberland,
Keswick, as he was going down into the deep pitts the ladder broke, and
the earth fell in upon him and so was bruised to death, and thus he lost his
life, and the vaine of gold not since discovered in Scotland." (This refers to
a reported vein of gold said to have been discovered by Bowes in Wanlock
Head).* "Mr. Daniell Hochstetter, one of the masters of the same copper
mine, was then going down after him into the ground, and fell but a little
way, and hurt himself, but not unto death (yet was) he sore bruised with the
fall from the same ladder (but he escaped), praised be God therefore.
wrought with him since, and he tould it me for a truth," &c.
I
IRELAND.-The abundance of gold ornaments and weapons found
in Ireland, and which are so peculiar to this people, clearly show that
considerable quantities of gold must have been obtained at an early
period in their history. Sufficient evidence of this is given in the testi-
monies of the ancient Irish writers. Delarnes, in his "History of Caen,"
states that when, after the Norman conquest of the British Islands, treasure
was exacted from both to the exchequer of Normandy, the tribute exacted
from England was 23,730 marcs of silver, but from Ireland 400 marcs of
silver and 400 ounces of gold—an enormous quantity for those times.†
Toward the close of the last century gold was accidentally found to
occur, disseminated in the beds of the streams which descend from the
northern flank of Croghan Kinshela, a mountain which lies on the confines
of Wicklow and Wexford, and at the junction of the granite ridge with the
clay-slate. It occurred in massive lumps, and in small pieces down to the
minutest grain. One piece weighed 22 ounces, another 18 ounces, others 9
and 7 ounces, and so on to the smallest particles.
The total quantity of gold collected by the Government-working, in about
two years, was 945 ounces, which was sold for £3,675. It has been com-
puted that at least £10,000 was paid to the country people for gold collected,
before the Government took possession of the works. This native gold was
* The editor of Atkinson's book, when printed for the Bannatyne Club (1825), says: "The story of
Mr. Bowes's vein of gold is a fiction. Gold is found in the alluvial soil only of the neighbourhood
of Lead Hills and Wanlock Head." Atkinson, speaking of the Scotch mines, says, "For thereby God
remunerates, the asker to have, the seeker to find, the hunter to follow, till that great blessing of God be
laid open, viz. God's treasure-house, even that bedd or vaine of gold or silver mine vallew'd at six
thousand-thousand times the charge of the adventure and labour."
+ Kane's "Industrial Resources of Ireland."
CHAP. VI.]
PRODUCE OF GOLD IN UNITED KINGDOM.
173
of a rich yellow colour, soft and malleable. An assay of 24 grains of it,
by Mr. Weaver, gave pure gold 20:58, silver 1'43.
The localities that have yielded gold in the largest quantity are Ballin-
vally, Ballintemple, and Killahurler, all situated in the same valley. The
gold is associated with magnetic ironstone, which is sometimes in masses
of half-a-hundredweight, also in iron pyrites, brown and red hæmatite,
wolfram, and manganese. Particles of native gold have also been found
at Croghan Moira, at Ballycrea, and Ballynacapoque.
PRODUCE OF GOLD IN THE UNITED KINGDOM SINCE 1862.
WALES.
AURIFEROUS QUARTZ.
Tons. cwt. qrs. lbs.
789 18 O o Poor
GOLD OBTAINED.
Ozs. dwt. grs.
732 19 о
1862 Vigra and Clogau
•
دو
13 16 I
2 Rich
4,566 I
12
1863
"9
324 7 I
14
526 18
6
1864
169 O
2,321
O
"">
1865
1,644 14
532
I
O
1866
•
1,159 19 O
8
213
14
22
1867
•
""
3,241 4 0 25
1,520
6 21
1874
""
1875
385 O I2
I 2
1876
""
1877
1878
1879
1880
""
548
228 18 8
139 4 13
697 12 15
447
7
21
9 19
12
1865 Cwmhesian
1863 Welsh Gold Co..
30
8
61
1864
1865
"
604
1,234 16
O
HOO
8 I 12
25
O
14
346 O
277
I
300
1864 Castel-Carn-Dochan
""
29 0
1,360 13 O
O
I4I
о O
1865
1866
. 1,763
1864 Prince of Wales.
20
ооо
1864 Gwynfynydd
•
4
ΙΟ
1865
1870
IO 2 O
NO
O
6
0
""
9 13
0
191
O O
""
837 16 O
529
65
I II
оо
1868 Sutherland, Helmsdale.
1869
""
SCOTLAND.
577
17 17 8
1876 Wicklow
1877
""
1879
1880
""
1880 Leinster
1881
""
IRELAND.
lbs.
201
472
220 quartz not treated
Ο O II 27 Value £18´o o
4 15 7
4 I 8
O
2
18
4 19 II
IRON.-Andrew Yarranton* says he "found out a vast quantity of
Roman cinders near the wall of the city of Worcester, and within one
hundred yards of such walls there was dug up one of the hearths of
Roman foot-blasts, it being then firm and in order, and was seven foot
deep in the earth; and by the side of the work there was found out a pot
* "England's Improvement by Sea and Land," &c. By Andrew Yarranton. (The first part was
published in 1677, and the second in 1688.)
174
[BOOK I.
HISTORICAL SKETCH.
of Roman coine-to the quantity of a peck-some of which was presented to
Sir Dugdale, and part thereof is in the King's closet; by all which circum-
stances it clearly appears that the Romans made iron in England, and as
far up the river Severn as the city of Worcester, where as yet there are vast
quantities remaining."
Dr. Nash* (in the absence of further evidence) strongly expressed his
opinion that these were not Roman relics, but in the corrections and addi-
tions to the second volume of his "History," he relaxed a little upon
the point, and stated that "In June, 1797, an underground search was made,
the whole length of the Broad Street, Worcester, and about the middle of the
street from the Cross, near the house of Mr. Morton, cabinet-maker, not far
from the Bell Inn, was found a bed of iron cinders, which extended up
Mr. Morton's yard, and probably on to the walls of the city, near which was
a considerable iron foundry in the time of the Saxons, or perhaps, as some
think, of the Romans. About two or three hundred yards from the city
walls, up the river, is a place called Cinder Point, where a great quantity of
the like scoriæ are found. The specimen I have is very rich in metal. The
cinders at Mr. Morton's and the Bell Inn were found to extend about forty
yards in breath; and at another place, near the Cross, opposite Mr. Wilson's,
about ten yards.
"I have several times examined the stratum of iron scoriæ and clinkers at
Cinder Point, on the east bank of the Severn, in a place called Pitchcroft,
and find that the bed is extensive and the clinkers very rich in metal. I
have no doubt that this is the place referred to by Yarranton. The stratum
lies by the river side about six feet deep, beneath the alluvial soil, and
was most probably the rough and half-smelted ore thrown aside in the
time of the Romans, they having, it is said, only foot-blasts to smelt the
ironstone.
"The supposed fort of Ostorius stood exactly opposite to the Cinder Point,
at the distance of about five hundred yards, on a ridge of ground, just out of
flood's way, on the same side of the river, and at all times a guard to the
ironworks. A few years ago I saw a similar bed of scoriæ and clinkers in
the bank of a lane between English Bicknor church and the river Wye, in
Gloucestershire. This was pointed out to me by the Rev. Edward Field,
then the rector of that parish, and now Bishop of Newfoundland."
Dud Dudley† states that in the beginning of the seventeenth century
there were no less than 300 furnaces in blast for smelting the ores of
iron with charcoal, the average annual make per furnace, about 13 tons
per week, giving an annual production of 180,000 tons, the estimated
consumption of charcoal being 144,000 tons, equivalent to 17,310,000 cubic
feet of timber. There is much uncertainty as to the period when the
manufacture of iron commenced in Great Britain. Mushet‡ considers it pro-
bable that the working of the tin mines of Cornwall by the Phoenicians
introduced into this country a class of men skilled in all the then known
metallic ores, converting them into useful products. With the invasion of
* "History of Worcestershire." By Dr. Nash.
+ Dud Dudley's "Metallum Martis; or, Iron made with Pit-coale, Sea-coale," &c. London, 1665;
reprinted 1851.
‡ "Papers on Iron and Steel, Practical and Experimental." By David Mushet.
CHAP. VI.]
DUD DUDLEY'S LAST PATENT.
175
England by the Danes, and their consequent establishment, much additional
knowledge of the art of mining and fusing ores was attained. Large heaps
of scoriæ are met with in many parts of England, with so great an accumula-
tion of soil as to grow trees of a large size. These heaps, known as Danes'
Cinders, have in recent time been reduced to the metallic state; and Dud
Dudley mentions that in the year 1620 oaks were found of a large size,
decayed, on the tops of large hills of cinder; and the same authority states
that about the same period.there were reckoned 500 forges and iron-mills
for refining the crude iron and converting it into malleable bars.
These works on an average made three tons each per week, for fifty
weeks, giving an annual production of 75,000 tons of bar-iron, in the manu-
facture of which it appears no less than 90,000 tons of charcoal would be
required for the year's supply at that period. The great consumption of
wood in those days appear in the fact, that the above 90,000 tons of charcoal
are represented by 10,732,000 cubic feet of timber, this quantity, with that
used in the blast-furnaces, amounting to 28,062,000 cubic feet; an acre of
ground being supposed to yield 2,000 cubic feet of timber. At the period
referred to, besides iron-works, smiths' and nailers' fires, manufactories of
every sort were carried on by means of wood, even at a time when pit-coal
was being exported to other countries.
<<
The enormous consumption of wood in the manufacture of iron was a
source of continued complaint. Accordingly, in Queen Elizabeth's reign,
this was so strongly felt that a petition was made to the Crown praying that
'the Bloomeries in High Furness might be abolished, on account of the
quantity of wood which was being consumed in them for the use of the mines,
to the great detriment of the cattle.'"*
Several Acts followed each other for protecting our forests.
In the time of King James, several patents for the manufacture of iron
with pit-coal were granted, but with little success, till Dud Dudley, in 1619,
succeeded in making coke pig-iron at the rate of three tons per week.
Previously, in 1612, Simon Sturtevant,† and in 1613, Ravenzon,‡ made ex-
periments in the same direction, but without success. During the Common-
wealth, patents were also granted, in one of which Oliver Cromwell was
a partner. Again, in 1663, Dud Dudley secured his last patent, setting
forth that at one time he was capable of producing seven tons of coke pig-
iron each week, the furnace being twenty-seven feet square, the blast im-
pelled by bellows, which one man could work for an hour without being
much tired.
It was not, however, till the beginning of the eighteenth century that the
successful application of coal, previously coked, was solved by Abraham
Darby, of the Coalbrookdale Iron Works, Shropshire, giving a new and
greater impetus to the iron industries of the kingdom.
The value of charcoal and coke pig-iron, and of malleable iron made
therefrom, in the year 1620 and later years, will convey some general idea
of the increased cost of materials and labour from time to time.
* "Guide to the Lakes." Hudson, Kendall.
+ Simon Sturtevant's "Metallica," 1612.
‡ John Ravenzon's "Treatise of Metallics,” 1613.
176
[BOOK I.
HISTORICAL SKETCH.
1620 Charcoal pig-iron
1792 Coke pig-iron
1798 Coke pig-iron
1620 Coke pig-iron, when invented
1792 Melting pig-iron
1798 Melting pig-iron
1620 Malleable charcoal-iron
1792
do.
do.
drawn into wire
1798 do.
do.
do.
1620 Bar-iron with coke
•
1792
Bar-iron with coke
1798 Bar-iron with coke
Per Ton.
£
S. d.
6 O O
8 IO O
ΙΟ О O
4 O о
5 10 О
7 10 о
15
23
27 to 28
12 O O
18 O
22 оо
The total production of pig-iron in the beginning of the seventeenth
century, as previously stated, was about 180,000 tons per annum, of which
112,500 tons produced 75,000 tons of bar-iron, of the value of £1,125,000, the
remaining 67,500 tons being converted into cast-iron guns, mortars, ship's
ballast, &c., of the value of £675,000, the total value representing £1,800,000.
The prices of the following varieties of malleable iron and steel about the
beginning of the last century was as follows:-Rod iron, £3 10s. per ton;
hoops, £7 per ton; blistered steel, £7 to £9 per ton; tilled steel, £10 to £12
per ton; and German steel, from £25 to £28 per ton; it being remarked
that the manufacturer of steel buys his iron at the rate of 20 cwts. per ton,
but in selling steel he gives 120 lbs. instead of 112 lbs. to the hundred-
weight, or 21 cwt. I qr. 20 lbs. to each ton.
SUSSEX.-"In the year 1844 Mr. Turner observed, upon a heap of
cinders, laid ready for use by the side of the London Road, a small fragment
of pottery, which on examination proved to be Roman. The scoriæ of
the disused furnaces are called cinders, and are much employed for the
repair of turnpike-roads. That they have long borne the improper name
appears not only from documents of ancient date, but from the designation of
many localities in the iron district, as Cinderford, Cinderhill, Cindersgill, &c.
"Mr. Turner became curious, and ascertained that the cinders had been
dug up from Old Land Farm, in his own parish of Maresfield. He visited the
spot, and found the workmen engaged on the undoubted remains of a Roman
settlement. The place is the site of one of the innumerable fields of iron
scoriæ marking the localities of the extinct furnaces and forges of the Weald.
Originally the bed was six or seven acres in extent, and of a depth from two
to twelve feet. A few days previous to Mr. Turner's visit, the labourers had
opened a grave about twelve feet in depth, at the bottom of which was a great
quantity of broken Roman pottery, evidently the remains of a funeral deposit.
The superincumbent stratification was as follows: the ground had been
excavated, first, through about one foot of earth, then through a layer of
cinders five feet in thickness, and, lastly, through about eight or nine feet of
earth. The cavity had been entirely filled up with cinders."
Previous to Mr. Turner's investigations, the digging had been carried on
for many months, and two years before that time the foundations of a build-
ing, measuring, according to the statement of the workmen, about thirty feet by
twelve, were uncovered; they were rudely constructed of stone, and lay about
six feet beneath the surface. A human skeleton in a very perfect state was
discovered at the same time, but it crumbled to dust on exposure to the air.
CHAP. VI.]
THE IRON-TRADE OF SUSSEX.
177
Several skeletons have been exhumed from the cinder-beds, in which the
bodies had been interred as in ordinary soil. If these be Roman interments—
which they undoubtedly are-we are led to suppose that they were made long
subsequently to the original deposit of scoriæ, since a recently formed cinder-
bed would have been a very unlikely spot to be selected for the burial of
the dead. The fair inference from these considerations is, that the iron-
works at this place were carried on by the Romans during a long series of
years.
The remains of Roman pottery are so numerous on this spot that scarcely
a barrow-load of cinders is removed but it contains several fragments;
though very rarely are any vessels found entire.
Several coins have been discovered, principally the second brass, of Nero,
Vespasian, and Tetricus-and a fragment, much oxidized, of one of Dioclesian.
Some coins have undergone the action of fire, and cannot be identified. The
coins of Vespasian are of common occurrence. Several remains of pottery,
glass, pieces of sheet-lead full of nail-holes, with fragments of wood adhering,
a quantity of broken bricks, and a stilus have been dug up.
From all evidence that has been obtained it would appear that the
Romans were but imperfectly acquainted with the art of smelting ores. The
most extensive ironworks carried on by the Romans in this country were
those in Gloucestershire. So large were these works, and so imperfect the
smelting, that in the sixteenth and following centuries the ironmasters,
instead of digging for ore, resorted to the beds of scoriæ for their principal
supply of metal. The scoriæ of Marefield retain a far greater proportion of
metal than the cinders of other beds in the neighbourhood, and are, on that
account, much more valuable for the purpose of road-making.
Roman remains have also been found at Sedlescombe and Chiddingly.
Iron was wrought by the Britons before the conquest of Julius Cæsar.
They must have used iron tools to construct their chariots and the formid-
able scythes; and Cæsar tells us their currency was principally iron rings.
The earliest actual record of the iron-trade in the south is contained in
the murage grant made by Henry III. to the town of Lewes. This grant,
dated 1266, empowers the inhabitants to levy the toll of one penny on every
cartload of iron, and one halfpenny on each horse-load carried through the
town.
A letter, written between the years 1233-1244, to Ralph, Bishop of
Chichester, by his steward, Simon de Senliz, appears to militate against the
existence of the iron-trade—at least in the western part of Sussex—at that
period. It relates to an order from the Bishop to one, H. de Kynarst, for
the purchase of iron ("x mureas de minnto ferro, si inveniri potest sive autem,
marcas de grosso, et v mureas de minnto ferro") to be procured in the
neighbourhood of Gloucester, and thence conveyed to the domus hospitis
at Winchester. This order would scarcely have been necessary, if the iron-
works which-in the next century-we find within a few miles of Chichester
had then been in operation. The letter was among the Tower MSS. No.77:
now probably removed to the Record Office.
In 1290 a payment was made to Master Henry, of Lewes, for the iron-
work of the tomb of Henry III. in Westminster Abbey.
Some years
N
178
[BOOK I.
HISTORICAL SKETCH.
previously, probably the same Master Henry was employed in constructing
the ironwork for the King's chamber.
Iron appears to have been smelted in St. Leonard's Forest in the reign
of Edward I., the works being carried on by the Crown.
In 1300, according to Stowe, the ferrones or ironmongers made com-
plaint to Elia Russell, Mayor of London, that the smiths of the Wealds
brought in the iron for wheels much too short, to the great loss of the iron-
trade. All the manufactured iron appears to have been brought to London
by water, owing to the impassable state of the roads.
In 13th of Edward II., Peter de Walsham furnished the King with 3,000
horseshoes and 29,000 nails for his expedition against the Scots.
The house returns for the parish of Lynch, in Western Sussex, prove the
existence of the iron-trade there in 1342. It also affords an early instance of
metals being subject to tithes: "Item dicimen ferri ecclesiæ practictæ valet
per annum decem solidi." The rector likewise received ten shillings for the
tithe of iron ore.*
Mr. Lower contributes the following: "The oldest specimen of this iron
manufacture is a cast-iron slab with an ornamental cross and inscription in
relief which exist in Burwash Church.
"The trade continued to increase during the fifteenth century; andirons,
and chimney-backs, of great taste were manufactured. The series of Sussex
andirons range from the end of the fifteenth to the seventeenth century.
"There are some old banded guns of wrought-iron preserved in the
Tower of London, dating as far back as the reign of Henry VI.; evidently of
Sussex manufacture, where the first iron cannons cast in England were
manufactured (1543).
"The manufacture of heavy ordnance caused the iron-trade to increase
so rapidly that several of the Sussex families became enriched, and assumed
the rank of gentry.
"About 1587 the ironmasters were in the habit of smuggling their cannon
abroad, upon the discovery of which they were all summoned by the Earl of
Warwick up to London, who made arrangements that only a certain number
of guns should be cast, which were to be sold to such merchants 'as my
lord or his deputy should name.' These commands, however, do not appear
to have been much regarded.
"During the seventeenth century the iron-trade of Sussex was at its
greatest prosperity. The reason of its decrease was the insufficiency of fuel,
which made the iron more expensive than in districts where coal was
abundant."+
PLUMBAGO.-Tradition informs us that the first discovery of the valu-
able deposits of plumbago in Cumberland was made by the uprooting, in a
storm, of a large ash-tree, growing upon the spot where "the grand pipe
reached the surface, lying between Farey's and Gill Level. We have no
satisfactory account of the original discovery of the Borrowdale Plumbago.
The following is from Mr. Otley's work. ‡
* Dallaway's "Rape of Chichester,” p. 300.
+ Notes from Mr. Mark Antony Lower, M.A., F.S.A., on the iron of Sussex. See Lower's
"Contribution to Literature, Historical, Antiquarian, and Metrical." John Russell Smith. London.
‡ Account of the Black-lead Mine in Borrowdale." By W. Otley.
((
CHAP. VI.]
THE PLUMBAGO OF BORROWDALE,
179
"The manor of Borrowdale belonged to the Abbey of Furness, which, at
the dissolution of the monasteries in the reign of Henry VIII., fell to the
Crown, and was granted to William Whitmore and Jonas Verdon by
James I. The grant also included the 'Wad Holes and Wad, commonly
called black cawke, of the yearly rent or value of 15s. 4d.' It was sold by
William Whitmore and Jonas Verdon to Wilfrid Lawson, and others, of
Borrowdale, with a reservation, 'Except the wad-holes and wad, commonly
called black-cawke, within the commons of Seatoller, or elsewhere within
the commons and wastes of the said manor.' On account of this reservation
the wad, or black-lead mine, has ever since been held separate from the
other royalties of the manor. In 1876 half of it was held by shareholders
and the other half belonged to Henry Banks, Esq., M.P.
"The mine has been opened in different places where the wad has pro-
bably appeared at the surface. It has only been worked at intervals, and
when a sufficient quantity was procured to answer the demands for a few
years, the mine was carefully closed up till that stock was reduced.
"On opening one of the old workings in 1769, it was found to have been
carried to a great extent without the help of gunpowder; and this vein being
pursued to the depth of one hundred yards and upwards, much inconvenience
was experienced in working it; to obviate which, in the year 1798, an adit,
or level, was begun in the side of the hill, which, at the length of two
hundred yards, communicated with the bottom of the old workings. Through
this level the water passes off, and the produce is brought out to be dressed,
and on its mouth a house is built, where, when the mine is open the
overseer dwells, and the workmen are undressed and examined as they pass
to and from work.
“This mountain consists principally of that kind of rock called grey-
wacké. A stratum of a darker-coloured stone runs through it, containing
more iron, the joints strongly tinged with oxide of iron. This is traversed in
various directions by strings, or small veins, exhibiting traces of wad, and
it is generally at the intersection of two of these veins that the valuable
bellies are met with, in one of which, opened in 1803, upwards of 500 casks
of the best quality were procured, containing about one hundredweight and
a quarter each, besides a greater quantity of an inferior sort. Since that
time two of these bellies have been met with, which have produced about
100 casks each.
"It comes from the mine in various pieces of an irregular shape, and of
various sizes, some weighing a few pounds, but the greater quantity in
smaller pieces. It requires no smelting or refining; the pieces are only
cleared from any stony or extraneous matter which may adhere to them, and
assorted according to the different fineness and sizes.
"An Act was passed 25th George II. cap. 10, by which an unlawful
entering of any mine, or wad-hole, or wad, or black-cawke, commonly called
black-lead, or unlawfully taking or carrying away any wad, &c. from thence,
as also the buying or receiving the same, knowing it to be unlawfully taken,
is made felony. In the preamble of this Act, wad is stated to be necessary
for divers useful purposes, and more particularly in the casting of bomb-
shells, round shot, and cannon-balls."
N 2
180
[BOOK I.
HISTORICAL SKETCH.
The specific gravity of the best wad is to that of water as two to one
nearly; the coarser is heavier, as it contains more stony matter.*
Blacklead is incapable of fusion, and was formerly thought to be incom-
bustible, but it is found to be a carburet of iron, in the proportion of about
nine parts carbon to one of iron, and being heated in a crucible with nitre,
or other substances affording a great quantity of oxygen, its texture is
weakened, and it is finally decomposed, the carbon disappearing and a
little ochreous matter being left behind. By keeping it some time immersed
in melted sulphur, the blacklead becomes impregnated with sulphur, and
being first reduced into slices of about one-twentieth of an inch in thickness
(the proper size for pencils), it may be thus brought to the degree of hard-
ness required. Pencils treated in this way may be known by the sul-
phureous odour and phosphorescent light emitted on rubbing the point upon
a moderately heated iron.
<<
'By an account drawn up in 1804, the stock then on hand was valued at
£54,000, and the annual consumption about £3,500; the best blacklead
was then sold at 35s. per pound. Since that time the price has been from
30s. to 45s. per pound, and no doubt the consumption has greatly increased;
and this mine, which 200 years ago was valued at 15s. 4d., has lately, on
assessing the property-tax, been estimated at £2,700 a year."
Hutchinsont writes: "There are two workings; the lower one is about
340 yards above the level of the sea, the upper one about 390 yards; the
perpendicular depth of the lower is about 105 yards, and of the upper
between 20 and 30 yards. There are no certain marks on the surface to
direct the miner to the mineral. The strata of the mountains are very
irregular and broken, and the blacklead probably was formed in the fissures
of the rocks. There is no regular stratum of this mineral; it is met with in
lumps and irregular masses. The miners generally work through a quantity
of earth mixed with stones of various kinds, then a species of hard grey
granite, and after that a dark-blue stone of a softer nature, where they
sometimes meet with it. Quartz and crystals are found in the workings.
The rock adjoining to this mineral is sometimes tinged as black as the
mineral itself, to the depth of two or three feet. The best sort is now
valued at three guineas a pound.
*The following are the most reliable analyses:-
SCHRÄDER* gives the following—¦
5'10
I.00
Carbon
82.25
Iron protoxide
5.80
Residue by in-
cineration, colour
yellowish brick-
Silex
Alumina
10'4
Oxides of iron
and manganese
3.60
red.
Loss
Silica
3°50
Alumina
2.30
Oxide of titanium
100'00
3.15
100.00
Dr. PERCY analysed a sample for Mr.
Salmon, which gave—
VANUXEM†–
Carbon
Water
83.37
1.23
Carbon
•
Ash
Water
* Bristow's "Glossary of Mineralogy."
↑ "Philosophical Magazine,” vol. Ixviii. p. 161.
† Hutchinson's "History of Cumberland," vol. ii. p. 212. 1794.
86.69
11.17
2.14
100.00
181
CHAP. VI.]
THE USUAL SALES OF PLUMBAGO.
"October, 1792. The wad mines were very unsuccessful for some years
past; but in the last year they met with blacklead again in a pretty large
quantity, but of the inferior quality, of which, in a short time, the miner pro-
cured about five tons. The mineral is described as lying in the mine in
form resembling a tree. It hath a body, or root, and veins or branches fly
from it in different directions; the root, or body, is the finest blacklead, and
the branches at the extremity the worst the further they fly. The veins, or
branches, sometimes shoot out to the surface of the ground. It is sometimes
found in slops, or floats, in a body without branches. A blue rock lies on
each side of the mineral, and sometimes there is a wet sludge between the
rock and the blacklead. The metal in the low mine lies in two veins, one
crossing the other; where they cross is the main body, and the best black-
lead; and these veins fall perpendicularly for sixty fathoms in depth, the
blue rocks on each side. At the end of sixty fathoms they found the end of
the cross vein, and a large sop of the mineral, which came out as if it had
been in a wrought basin, the form of the rock and of the blacklead were so
equal.”
There is a vein of plumbago which has been slightly worked occurring in
the Bannerdale Lode. Hardly any good plumbago has been found in this
vein; most of that which was obtained was of the grate-polishing quality.
This vein runs east and west.
Mr. G. F. Crosthwaite, of Keswick,* states: "The mine has eight
stages, thirty veins, eight pipes, and four great sops or bunches of wad,
or plumbago, as it is usually called. In Winkles pipe, at the meeting of
the veins, a sop was discovered in 1812, which produced 87 casks of
best lead for pencils, and 495 casks of coarse lead, in all 582.
The 87
casks of best lead alone would realise £24,360. The grand pipe, which
was the one discovered by the uprooting of an ash-tree, was wrought to
the depth of 64 yards to the top of Harrison's pipe. In 1778 no fewer
than 417 casks, containing about 70 lbs. each, of the best quality, were
extracted; this at 30s. per lb. would amount to £43,785. There were
besides two other openings of this pipe in the ten years ending 1788. In
1802-3 Dixon's pipe was discovered, when ore to the value of £98,742 was
got. So valuable a mine needed more than ordinary protection. Conse-
quently an Act of Parliament was passed enacting that any one breaking
into the mine, or picking wad or black-cawke at the rubbish-heaps would be
guilty of felony. Notwithstanding, some blacklead did find its way to
Keswick, and Jews came regularly to the George Hotel to buy it. The
owners had all the mineral taken to London, and monthly sales were held
at their warehouse only. Thus any sold privately in the country must have
been got dishonestly, except scattered pieces, which were not unfrequently
found in the beds of the streams washed down by the floods. Great care
was taken to guard the mine. A house was built over the entrance and
guards slept there with firearms. When the ore was taken to London in the
six-horse waggon then used by carriers, half-a-dozen men, armed with
blunderbusses, slept in the warehouse with the precious load, and guarded it
on its way as far as Kendal. The present worthy steward of the mine is the
* "Old Borrowdale." Communicated to the Cumberland Associations, June, 1875.
182
[BOOK 1.
HISTORICAL SKETCH.
fourth of the name who has held the office with great reputation for integrity
and ability. His great-grandfather, Thomas Dixon, came from Langdale
one hundred and fifty years ago, and his descendants have continued in
office till the present time. The mine is now being reopened, and it is
hoped that it will be a profitable undertaking for all concerned. This is
the only plumbago which can be made into pencils to stand a point in its
natural state, and is the purest and best in the world." Elsewhere Mr. Cros-
thwaite tells us, "The plumbago mines were wrought in the reign of
Elizabeth by some of the German miners, who also wrought the copper
mines in Newlands."
Since this was written the author has been favoured with the loan of a
remarkable report, made by Farey, the full title of which is below.*
"The preliminary, or First Report, which I (John Farey) had the honour
to make and deliver to Mr. Bankes, on the 17th September, 1818, in a small
quarto, sewed in a paper cover, is said to contain several inaccuracies, which
are to be corrected in this second report. This report is divided into seven
parts, in which the underground and surface workings are all described, and
an account given of the pipes, sops of wad, glazes of wad, and sludge."
Five old plans and sections are then enumerated.
The sketch, by Mr. Harrison, in September, 1789.
The plan, without a name or date, sent to Mr. Bankes in the spring of 1792.
A plan, by Joseph Saint, in 1796 (said to be very confused).
Two plans, planned in 1794 by J. Foulkes, from diallings and measure-
ments taken in 1778 and 1791, by Thomas Temperley and Thomas Kent.
In these the old men's workings are especially referred to, but we gather no
information as to the date of these workings.
Very elaborate descriptions of the workings, old and new, are given, and
the diallings are most clearly and cautiously laid down. One point especially
calls for attention. All the plans and sections are drawn with especial
reference to the magnetic north, and the variation of the needle is given to
the day upon which each plan was constructed. Mine surveyors should
profit by this.
Farey advises that no further surface workings should be undertaken,
and in giving his reasons for this, he describes conditions which give a good
general idea of the old workings. He writes as follows: "The three
instances of sops of wad actually reaching up to the surface of the rock, and
* A second Report, accompanied by four large Maps, Plans, and Sections (rolled in a tin case), and
containing herein particular PLANS and SECTIONS, Lists, Statements, and Descriptions of all the
workings of the
WAD MINE,
or Mine of Graphite, Plumbago, or Black Lead, situate on the N.W. of the village of Seathwaite, in
the Manour of Borrowdale (of which Manour a general map is included), in the Parish of CROSS-
THWAITE, in the County of CUMBERLAND. Belonging to HENRY BANKES, Esq., of Kingston Hall,
Dorset, and at present occupied by himself and others as a Company of Lessees, under a Lease from him
which expires July, 1860.
Accompanied also by a Supplement and Index to the Book of Directions, which was delivered to the
resident Agent on the spot, in January, 1820, as to the future conduct of the several Departments of the
business of the mine, and a series of Trial Drifts and Risings, which are recommended to be successively
undertaken in search of new SOPs of WAD.
By Mr. JOHN FAREY, Sen.,
Mineral Surveyor and Engineer,
Rowland Street, London.
A manuscript book of 210 pages, with Maps, Plans, and numerous Sections.
31st October, 1821.
CHAP. VI.]
MANGANESE IN DEVONSHIRE.
183
the recent circumstances of the wad in Grisdale's pipe having reached within
sixteen yards of the surface, would still seem to justify an expectation that
other valuable sops might yet be discovered by surface trials; but, consider-
ing how extensive a search the miners of early times made, when the flush-
ing, or washing away of the alluvia or surface soil that took place in order
effectually to examine the rock, whereof the Seven Gills are a memorial,
considering also the large space trenched or dug and turned over quite down
to the rock in search of lumps of flobe wad, as is recorded; these, and the
dangers and difficulties which would attend fresh discoveries of wad on the
surface, all concur in showing the propriety of the opinion and advice. .
that no further open surface trials ought to be undertaken."
These surface trials were no doubt made by the Germans, and with this
feeling a large fissure has been called the German's Vein. It is not easy to
admit the existence of a real mineral vein in any part of the workings of this
mine. The irregularity of the deposits, producing "pipes" and "sops of
wad,” and “small sops," and "bullets of wad," preclude the idea of anything
approaching to the regularity of a fissure vein, although the miners have
invariably used that term. In 1769 a very large "sop" was discovered, “but
the number of casks which were anciently got therefrom cannot now be
ascertained."
"The Old Men's Third Sop was by far the largest one which has been
found. The date of its discovery was too far back to have been preserved,
but it is believed to have been the third sop discovered, and it continued in
occasional work until the year 1750.
<
"Wickersley's Sop was discovered in 1769, behind a rider or partition
of vein stuff. This produced 177 casks of that denominated best wad.' The
coarse wad, which probably would have amounted to 223 casks, was, with its
vein stuff, stowed away on or behind 'bunnings' in the grand pipe, and on
the next opening of the mine in 1778 the whole of this was ground down to
coarse powder and thrown away into the stream."
"The
In 1778 a sop, called the Great Opening Sop, was discovered.
quantity sent away from this sop to London was 417 casks; besides great
quantities were pilfed." A statement is made in a note by Farey that several
men "sold wad creditably asserted to have been stolen, to the amount of
£300." Several men were searched, and they "were all found with wad
concealed upon them when leaving work." The mine was closed in
September, 1788, and remained so until 1800. The further consideration,
therefore, of this remarkable mine, which has been occasionally worked up
to 1876, is postponed to a future page.
MANGANESE.-According to Lysons, manganese was first raised in
Devonshire about the year 1770, at Upton Pyne, near Exeter; the ore from
which, with two other mines of less consequence, at Newton Saint Cyres,
is said to have supplied the whole county.
At Doddescombleigh, at Ashton, at Christow, and other places in that
neighbourhood this mineral has been worked.
In 1815 the mines in the neighbourhood of Launceston and Tavistock
were discovered and worked. The return of the production of Manganese
has been in 1880, 2,839 tons, and in 1881, 2,884 tons.
184
[BOOK I.
HISTORICAL SKETCH.
DERBYSHIRE produces annually-from about six mines-a few small
parcels of manganese.
WALES produced from Nant Uchef, in 1881, 300 tons.
WARWICKSHIRE.-Manganese was first obtained in Warwickshire at
Hartshill, on the estate of T. L. Ludford, Esq., of Ainsley Hall, about two miles
from Atherstone. A man of the name of Hankinson has since found this
mineral in his land, which adjoins Ainsley, and raised a considerable
quantity. A man called Davis has also raised some, and sold it at a good
price to the bleachers in Lancashire. The soil in the neighbourhood is
chiefly a red clay, and the manganese usually occurs in detached pieces,
distributed through the clay, from one to eight feet below the surface,
weighing from one pound to fifty or sixty pounds each.
IRELAND. From Glandore the following quantities have been obtained:-
1877
1878
1879
50 tons.
50
""
40
""
1880
1881
ΙΟΟ
250 ""
ANTIMONY.-The production of antimony has been small in Corn-
wall-from 20 to 30 tons per annum. In the three years from 1778 Cornwall
produced 120 tons. The mine at Endelion produced as follows:-
Wheal Boys. Endelion-in 1774
19
"
""
1775
o at £130 per ton
40 O ,, £13 10
""
""
""
1776
36 0,, £14 14
95 o
The expense of getting this antimony, exclusive of driving an adit to the
mine, has been less than one-third the amount of its produce.
Twenty-five tons of antimony was obtained from a mine at Saltash,
belonging to Mr. Thomas Reed and partners. Antimony has also been
raised in St. Austell parish-at Howton in St. Stephen's—and in a place
called by Dr. Woodward, Barbary, and in St. Kew parish.
SOMERSET (N.W. quarter).—Only a few specimens.
DEVONSHIRE.-A few tons only have been raised in this county.
COBALT.—Mr. Beauchamp, of Pengreep, in Cornwall, in driving an
adit through some part of his estate in Gwennap, discovered a lode of three
feet breadth, which contained a branch of "real cobalt." It did not hold
in depth, and was soon abandoned. The Society of Arts, in 1754, gave
Mr. Beauchamp their premium of thirty guineas for the best cobalt then
discovered in England.
At Wheal Trugo, near St. Columb, in a copper mine, a small vein of
cobalt was found from four to six inches wide; it was estimated as worth £60
per ton, but little was, however, sold.
Dolcoath mine produced a small quantity of this mineral. Dudnance, in
Illogan, yielded a little very good cobalt. Pons-a-Nooth, Perran-Arwothal,
was worked for cobalt and nickel, for a year or two, and then abandoned.
CHAP. VI.]
BISMUTH AND URANIUM.
185
Wheal Sparnon, near Redruth, produced much cobalt about the years
1815-17. This was of a high character.
Hawke's Point copper mine, in Lelant, near St. Ives, has been found to
produce arsenical pyrites, which contains both cobalt and nickel.
The Wherry mines, near Penzance, produced some cobalt, and it is said to
have been manufactured at Newlyn into smalts.
Cobalt ore was found at Alderley Edge, in Cheshire, and a manufacture
of smalts was carried on for some years, but ultimately abandoned.
BISMUTH.—When in 1754 they found cobalt in the lands of Francis
Beauchamp, Esq., in Gwennap, bismuth was discovered associated with it.
Borlase says: "This bismuth was quite thrown away till the learned and
sagacious Dr. J. Albert Schlosser, F.R.S., came to view it, September 8th,
1755, who extracted the cobalt tint for glass and smalts, and preserved the
bismuth. We call bismuth 'tin glass."."
I have received, when resident at Falmouth, large lumps of bismuth, said
to have been collected from the waste-heaps at Dolcoath mine. I obtained
from a Mr. Curnow a lump of bismuth, which he found in a stream flowing
down a valley about two miles west of Penzance, near a "Jews' house,
several feet under accumulations of peat.
This metal has also been found in St. Just and at St. Ives.
MOLYBDENA, Borlase says, was found "at a work in Camborne called
Huel Crofty." I have seen fine specimens of molybdena found on the waste-
heaps of the United mines in Gwennap.
URANIUM.—The only mine in Cornwall which, until within the last
few years, was known to contain the oxide of uranium was that called
Carharrack, which was situated about two miles nearly south of St. Die (St.
Day). Mr. W. Phillips thus describes some specimens: "The crystals on
a specimen from that mine in my possession are tabular, of a green colour,
and transparent, except such of them as are partially or wholly coated by a
deposition of an ochreus substance similar to that termed gossan by the
miner. . . . . On many of the crystals have been deposited numerous minute
cubes of a light green colour, which, as there is a considerable deposition of
cubic arsenical iron in a cavity of the same specimen, I consider to be that
substance rather than the oxide of uranium.” *
In 1805 Mr. Phillips found oxide of uranium on the refuse-heaps of
Tin Croft mine, near Camborne. The crystals were found for the most part
well defined, and some of them are accompanied by black pechcrz (the uran.
oxyanté of Hauy). These were found at about go fathoms from the surface
in a copper vein.
Mr. Phillips also obtained beautiful and well-defined crystals from Tol-
carn mine, about two miles north of Carharrack. The veins in Tolcarn
afforded little or no copper. The uranium was found in one of them at about
30 fathoms from the surface.
In Wheal Jewel specimens of red oxide of copper were covered with
numerous minute tabular crystals of the oxide of uranium of a light green
colour; and a specimen from Stenna-Gwyn, near St. Austell, Wavelite, has
* "On the Oxide of Uranium." By William Phillips. ("Transactions of the Geological Society,"
1816.
vol. iii
186
[BOOK I.
HISTORICAL SKETCH.
deposited upon it crystals of the oxide of uranium of a light yellow colour.
But by far the finest specimens of this mineral were found at Gunnis Lake
copper mine in 1811-12, near Calstock, many of them more than half an inch
in diameter.
Within late years pitchblende (uranium protoperoxide) has been
obtained from Wheal Edward and Botallack, St. Just, Wheal Trenwith,
Wheal Providence, Wheal Basset, Wheal Balen, Tolcarne, Pednandrea
(mamillary), Roskrow, United Ponsanooth, and a few other mines. The little
that has been obtained found purchasers at about £26 4s. 4d. per ton.
STRONTIAN.-Masses of sulphate of strontian have frequently been
found in the New Red Sandstone of the counties of Gloucestershire and
Somersetshire. Near Wickwar, Charfield Green, and the northern brow of
Tortworth Hill, where a small patch of the New Red clay marl covers
the line of Calcareous Conglomerate that surrounds that hill, beautiful
samples of this mineral have been found. They are discovered also in the
Keeper's Ridge, in which also exists a bed of fine white granularly-foliated
gypsum. The general distribution of sulphate of strontian in this part of
the kingdom is remarkable. Near Bristol it has been found at Pyle Hill
in the Carboniferous Limestone. At Cromhall, Mr. Weaver observed it in
the Slate-Clay of the Coal formation. It occurs plentifully in the Calcareous
Conglomerate, the Magnesian Limestone, and the New Red clay marl. In
the Lias Limestone it is found in the Aust Passage, Clifton, and also on the
Somerset coast near Watchet and at Berkeley. In the whole succession
of formations, from the transition beds up to the Lias Limestone, strontian is
found. It appears to be wanting only in the Old Red Sandstone. In
Yorkshire, strontian is found at Scotton Moor, and on the Nidd near
Knaresborough. In Glamorganshire, South Wales, it occurs on Barry
Island, eight miles from Cowbridge. Strontian derives its ordinary name
from the well-known district in Scotland. It is also found in Carlton Hill,
Edinburgh; at Elgin; and pale-blue specimens of Celestine (from Cælestis,
sky-blue) at Haddington, and near Inverness.
X
* "Geological Observations in Part of Gloucester and Somersetshire."
("Transactions of the Geological Society," Second Series, vol. i. p. 317.)
By Thomas Weaver.
BRITISH MINING.
BOOK II.
ON THE FORMATION OF METALLIFEROUS DEPOSITS.
CONTENTS OF BOOK II.
CHAP. I. THE ROCKS OF MINING DISTRICTS AND THE DISTRIBUTION OF METALLIFEROUS DEPOSITS.
"
II. MECHANICS OF MINERAL LODES, FAULTS, CROSS COURSES, ETC.
III. THE LAWS RELATING TO MINERAL DEPOSITS.
",
IV. REMARKABLE PHENOMENA OBSERVED IN METALLIFEROUS ORE DEPOSITS.
BRITISH MINING.
BOOK II.
ON THE FORMATION OF METALLIFEROUS DEPOSITS.
CHAPTER I.
THE ROCKS OF MINING DISTRICTS AND THE DISTRIBUTION OF
METALLIFEROUS DEPOSITS.
ވ
THE distribution of metalliferous ore deposits over the surface of the British
Islands claims our close attention. These deposits appear to be scattered
irregularly, sometimes in rocks of one age, sometimes in those of another.
Not unfrequently they are found distributed in strata differing not only in
geological age, but in physical condition and also in chemical composition.
From these circumstances it has too often been assumed that there is no
rule upon which reliance can be placed, by which the miner may be guided
in his search for mineral treasures. The uneducated toiler after subterranean
wealth, following without examination in the footsteps of his fathers, satisfies
himself with industriously digging into the earth, rather pleased than other-
wise with the phrase, “It is only by cutting the ground that the metal is found;
thus admitting his ignorance of the operation of any law; the miner
sagaciously declaring of any metallic ore, that "where it is, there it is."
The consequence of this is, that actual mining gives us but little
evidence, over long periods of time, of any practical advance. The miner,
notwithstanding the solitary nature of his labour, is by his training a
good observer. His often anxious search for the indications of the mineral
for which he delves leads him to observe minute peculiarities, which
would, if recorded, be of really considerable value, and form eventually a
system by which the miner's younger brethren might be guided. But it is a
rule with the untrained mind to treasure every truth as a mystery, to be
carefully guarded for individual use only. Experience has often well stored
an individual mind with valuable facts, but these are rarely recorded. The
miner trusts to his memory, and when he dies, all the results of a long expe-
rience die with him. The son has to begin where the father began, and this
is repeated from generation to generation: consequently there has been no
advance. A better system is happily beginning to prevail. Several attempts
have been made to give the more intelligent of the young miners instruction
190
[BOOK II.
THE FORMATION OF DEPOSITS.
in those branches of science which have a direct bearing upon the varied
operations in which they are engaged. In Cornwall, the late Sir Charles
Lemon established, and supported for some years, a mining school at Truro,
but that was eventually abandoned, the experiment not being successful. The
author of this volume thought that the cause of this failure could be traced to
the fact that the miner could not afford to visit the school in Truro. He
therefore, in 1858, proposed that classes should be formed in the mining
centres themselves, and that trained teachers should regularly visit these,
and give the required instruction to the miners, in their hours of rest, and
in immediate proximity to their homes. The experiment was commenced
by a public meeting held on October 26th, 1859. Classes were organised
in all parts of Cornwall and in Western Devon, and on the 1st February,
1861, the first general meeting was held. In some districts the classes have
been well attended; in others they have worked well for a season, and then
they have been allowed to die out. A great many of the students who
attended the "Miners' Association," however, distinguished themselves, and
are filling important positions at home and abroad. The subject of scientific
instruction will form matter for serious consideration in the last division of
this volume.
It must be admitted that the process of introducing a system by which
observed phenomena connected with the physics and chemistry of rock for-
mation, and of the depositions of metalliferous ores, is slowly making satis-
factory way. The establishment of the "Mining Institute" in Cornwall
is of good omen. Mining agents are induced to read papers on technical
subjects, and these, being brought forward, are carefully discussed by the
members at the meetings. Technical instruction in schools and colleges is
also producing promising results. The advantages of those attempts belong
properly to the consideration of the mining of the future.
With these remarks, let us advance to our legitimate inquiry. Are there
any natural conditions known to be in operation in the Earth's crust
to which we can trace the phenomena of mineral deposits? Can such
phenomena be used in guiding the miner to the discovery of productive ore
deposits?
If we examine the maps of the Geological Survey on which the mineral
veins are marked, it will be seen that the ores of the useful metals are
generally gathered into groups in special districts. Cornwall and Western
Devon, forming one of the most important of our mining regions, demands.
our first consideration. A few miles westward from Exeter we reach the first
group of metalliferous mines. The lead mines known as Frank Mills, the
Wheal* Exmouth, and a few others, are here gathered together. As is not
uncommon, in each of the mines named, the deeper portions of the veins.
passed from lead into iron, in the form of spathose iron ore.
In the Teign
Valley a large deposit of barytes has been found. Similar conditions
prevail with the lead and barytes mines of the Northern English counties.
* Throughout this volume the term "Wheal" will be used. In the "Mineral Statistics of the
United Kingdom" I have constantly employed, since 1847, the term "Huel," which is undoubtedly the
ancient Cornish term-signifying a mine or mineral work-but the corruption "Wheal" is so unde-
viatingly used by all, that there is no reason why I should any longer endeavour to bring the older term
into use again.
CHAP. I.]
DISTRIBUTION OF MINES.
191
Lead ore has also been found in North Devon, in the neighbourhood of
Ilfracombe and of Combe Martin.
A few miles westward of the Exmouth lead district, "lodes" (the term used
in Western England for mineral veins) of several kinds of iron ore are found,
especially near Ilsington; and close to Ashburton are some large deposits of
ochre and umber. In the immediate neighbourhood of Buckfastleigh valu-
able deposits of copper ore have been discovered, and at one place rather
extensively worked. Advancing still westward to the neighbourhood of
Plympton, we have the Old Bottle Hill and other tin mines,-producing also
small quantities of copper ore, in the neighbourhood of Hemerdon Ball,—but
these are not now worked, except for the arsenical pyrites at Wheal Mary
Hutchings, from which considerable quantities of arsenic are being sublimed.
As already stated, manganese has been found and worked on the eastern
side of Dartmoor, and similar deposits have been discovered from time to
time on the western borders, especially in the neighbourhood of Milton Abbot
and Launceston. On the banks of the Tavy several mines of good argenti-
ferous galena have been explored, and in the neighbourhood of Tavistock
there have existed some of the most remarkable veins of copper ore which
have ever been found. The district extending from Tavistock westward to
the Tamar may be regarded as a rich copper-bearing locality, and this
peculiarity extends on the western side of the river as far as Hingston
Downs. Those mines in nearly all cases yield also a small quantity of
tin. A peculiar tract of country in the neighbourhood of Harrowbarrow
has been remarkable for mines which have produced considerable quantities
of silver ore; and at Wheal Duchy, near Callington, a course of silver ore worth
£200 a fathom was found, and Wheal Brothers in the same locality gave
at one time great promise as a silver mine. Some few mines in Mid Corn-
wall and in the western district have also produced silver ores. At Crinnis
Fahlerz was found, and small quantities of silver ore are now (1882) being
raised. At Herland mine, in Gwinnear, several thousand pounds' worth of
argentiferous ores were obtained about half a century since. Dolcoath at one
time gave promise of being rich in silver, but the deposits have only pro-
duced about two thousand pounds' worth, and no more silver ore of any
consequence has been discovered.
In the neighbourhood of Liskeard, in the parish of Menheniot, some
important lead mines have been productive, and there is every probability
that explorations now in progress will prove to be further successful. The
copper mines on and around the Caradon Hills have been very rich and
enduring. In the Granite masses near the Cheesewring many productive tin
mines have been discovered. The moors extending from Bodmin to St. Austell
have yielded large quantities of tin from the alluvial deposits, and some
important tin mines have also been worked in the district. An extension of
the peculiarities of the St. Austell district is found stretching away westward,
but the deposits have proved generally poor, and there are many unproduc-
tive spots. The lead-producing district of St. Newlyn East-in which we
find the important mines of East Wheal Rose, of Old Shepherds, and Cargol
-appears to extend with but little variation to the Chiverton parish and its
neighbourhood, where some valuable lead mines have been worked. These
192
[BOOK II.
THE FORMATION OF DEPOSITS.
Τμ
may be traced on to the great iron lode in Perranzabula, where, in connec-
tion with, but beneath the spathose and brown iron ore, large deposits of
zinc ore have been worked, and several strings of silver lead ore with some
native silver discovered. The parish of St. Agnes has been especially rich in
tin mines, and indeed all the cliffs around that parish and on to Perranzabula
afford striking examples of ancient tin workings. The Great St. George
mine and others near Perran-Porth have proved productive of copper, and at
Wheal Prudence copper lodes may, at low water, still be observed running
out under the sea.
All the country from St. Agnes to Redruth, and onwards to Camborne,
has proved peculiarly rich in mineral deposits. In this and in the Gwennap
district mining has been carried on more extensively than in any other part
of the United Kingdom, and it may be distinguished as the most highly
mineralised tract of country in these islands. In these mines tin, copper
zinc ore, blende (or the Black Jack of the Cornish miners), and pyrites have
been found in vast abundance. Wolfram has also been worked, and the
rarer minerals, cobalt, nickel, molybdena, &c., found.
Extending from this important piece of country towards the south,
we have a remarkable series of tin mines, some of them, especially the
Wheal Vor series, being the richest ever discovered. Copper ore has also
been found, and in the mines near the south coast, Wheal Rose and Wheal
Penrose have given lead ores very rich in silver. The latter mine, espe-
cially, has been productive, according to the tradition of two centuries, of
very argentiferous lead ore. On the coast, advancing towards Marazion,
some rich deposits of copper have been worked. Near Penzance, in the
parishes of Madron and Sancreed, large tin mines have long existed. Indeed,
Ding Dong tin mine is probably one of the oldest mines to be found in this
country-possibly in Europe.
The St. Just district, rich in its copper and tin mines, is distinguished by
many peculiarities, which will form the subject of future consideration.
Such is an outline sketch of the great mining district of Western Eng-
land, and before we leave it, it is important that we should institute a
careful examination of some of the natural phenomena developed by the
mining explorations of the district.
We find that the prevailing rocks from Dartmoor to St. Just (the Land's
End) are Granite and Killas, or Clay-Slate, with here and there masses of
Greenstone and frequently veins of Elvan.
Although mineral deposits will be found in all those rocks, and some-
times disseminated through them, yet, as a rule, the most productive portions
of the lodes will be found near the junctions of two dissimilar rocks. The
Granite hill of Carn Brea, surrounded by a wide area of Clay-Slate, is a
striking example of these conditions. On this hill and around it—near the
junction of these rocks—are some of the most valuable of our mines; and
as we extend our examination away from the lines of junction, the mines
become less frequent, and they certainly are less productive of metalliferous
ores.
It may therefore be taken as an established fact, that, in Cornwall and
Devonshire, the junction of dissimilar rocks has a tendency to produce a richer
CHAP. I.]
METALLIFEROUS CHARACTER OF ROCKS.
193
deposit of metalliferous ores than are found in the same rocks at a distance from
he junction.
To understand, or even to make an approach to any knowledge of the
conditions under which lodes or veins are formed, it is necessary that the
structure of our rock formations should be studied. If we examine with
attention a geological map, made from a careful survey of the British Isles,
we cannot but observe a marked distinction between the rocks which occur
in the eastern counties, and those which distinguish the midland and western
districts of England and the whole of Wales. From Redcar, in the north-
west, we see peculiar layers of rock passing irregularly in a direction, nearly
southward, to Grantham, and then, with a western deviation, striking towards
Gloucester and the mouth of the Severn. These rocks are-from their system
of layers-known as Lias. From the banks of the Severn they make several
westerly extensions, and then stretch away to the southern coast, and reach
the English Channel about Lyme Regis. The rocks to the eastward of the
Lias belong to the Oolitic series, and to the Cretaceous and Eocene formations;
those to the westward being Carboniferous, Devonian, Silurian, and Cam-
brian rocks. Throughout the whole of the eastern region there is almost
an entire absence of those metalliferous minerals, other than iron, which are
of commercial value. The iron ores-although abundant in Cleveland, in
Northamptonshire, and in Lincolnshire, and occurring in Oxfordshire and
the neighbouring counties-have in no case the character of veins or lodes.
In distinction we find, to the westward of the Lias, the New Red Sandstone
and Magnesian Limestones, with the extensive Coal Measures, Millstone
Grit, Carboniferous Limestones, and Shales-presenting evidences of another
order: mineral veins of lead and other metals occurring to a greater or less
extent in all of them. To the south and south-west of these rocks, we reach
the Old Red Sandstone, or Devonian series-and in Leicestershire, Devon -
shire, and Cornwall, Granitic and Greenstone rocks occur, with Felspathic
Traps and Basalt; all these rocks presenting, in the last-named counties,
marked systems of lode formations rich in ores of the useful metals.
Thus we learn that to the eastward of the line indicated—that is, from the
mouth of the Tees, in the north-east, to the coast of Dorsetshire-there is an
absence of the metallic ores of lead, copper, tin, and the like, which occur in
a peculiar way to the westward of that series of rocks which belongs to a com-
paratively recent period, and are distinguished as Secondary or Mesozoic
and Tertiary or Cainozoic formations. Iron ores must be excepted—as ferru-
ginous deposits may occur in the most recent as well as in the oldest rocks.
We must infer from these facts that there is a definite law-or, probably, a
set of laws-with energies, differing in degree, but acting to a common end,
which determine the deposition of the metallic ores in the previously-formed
fissures of the older rocks, from the Upper Lias to the Lower Silurian or even
possibly to the Laurentian Gneiss.
We may state our conviction that metalliferous matter, either in a state
of physical purity, or in several peculiar mechanical mixtures, or definite
chemical conditions, have been disseminated at all times through a certain
class of rocks. These rocks differ greatly in their richness, and also in the
variety of these metallic substances. Attention has naturally been directed
O
194
[BOOK II.
THE FORMATION OF DEPOSITS.
to the local characteristics by which any especial region is distinguished.
The "nature of the rocks" is constantly appealed to by experienced practical
miners, as evidence of their "richness" in metalliferous ores, or of their
poverty in such. Although the predictions of the observer-founded on the
amount of his lithological knowledge—may be of very different degrees of
value, yet, in nearly all cases, it proves that the evidence given by observa-
tion is of some real importance, and that it may be, to a certain degree,
relied upon as a temporary guide. Admitting this, it is necessary that a
short space should be devoted to a consideration of the primary conditions
of the metal-bearing rocks, and of the alterations which may have taken
place in their mineral characters.
The solid masses which form the superficial strata of the Earth, often
called the Earth's crust (a term adopted naturally enough from the hypothesis
that this globe was at one time a fluid, possessing a certain amount of homo-
geneity, the result of igneous action, which slowly cooled from the surface).
It is useless-especially in a work of this kind-to wander into speculations
respecting the beginning. Vast mutations, continued through countless ages,
have constantly been in progress, and the earliest forms of matter have under-
gone mechanical or chemical changes, by which all the known conditions
of rock formation have been produced. In addition to the purely physical
phenomena, there must have been through all time, as the result of the action,
either of heat, of electricity, or of chemical influences, vast changes-
often called metamorphoses-which eventually produced those lithological
varieties with which we are acquainted. It should, however, be remembered
that our knowledge is limited to about 4,000 feet beneath the very surface upon
which we exist, and that we know nothing of the enormous mass extending
to the centre of the globe.
The changes which have taken place are very varied in their character.
Some rocks are simply formed by the abrasion, or disintegration, of pre-
viously existing masses, the fine matter worn off being held in cohesion
by the molecules having been subjected to considerable mechanical force.
The detrital matter in other cases has been consolidated by some cementing
substance, such as silica or lime. Many of these have again been disin-
tegrated by the influences of chemical action. Evidences of convulsive force
are seen in some. Fragments have been broken off, and these,-sometimes
water-worn pebbles,-have been agglutinised into conglomerates, or angular
fragments have been cemented together, forming breciated masses.
Other, and not unfrequently vast, strata have been exposed to the influences
of heated masses of igneous rocks which have been protruded through them.
GRANITE or MOORSTONE.-The first is a modern name given to
this rock by Italian writers-Granita, i.e. è granis composita. The parts of
Granite are not homogeneous, but are different concretions of quartz and
mica. Such is the definition of Granite given by Pryce in his "Minera-
logia." The same author continues as follows: "The varieties in the west
of England are of five sorts—the white, the dove-coloured, the yellow, the
red or Oriental granite, and the black or true Cornish. Either of these as a
stratum is called a Hard grouan country (in the Swedish tongue, Graberg
and Grasten). Grouan strata are disposed for tin, which in such situations
CHAP. I.]
GRANITE AND GREENSTONE ROCKS.
195
is generally of a rich quality, or cannot long be sought after or wrought in
its almost impregnable walls. They are seldom likely for copper ore, and
were long thought to be wholly adverse to that mineral, till the great mine
of Tresavean proved that rule exceptionable." *
Of the varieties of ordinary Granite Mr. Joseph Carne remarks †: "With
respect to the more particular and local varieties of Granite, to describe them
would be an endless task. They are almost as many as all the possible com-
binations of its three (or, including shorl, we may say its four) constituent
substances can give rise to."
There are, however, four varieties of Granite which have more especially
some relation to mineral productions. 1. A variety, which may be called
porphyritic Granite, is studded throughout with large crystals of felspar.
2. A variety which deserves notice from the almost uniform minuteness of
the grains of which it is composed. This Granite prevails on the sides of
Pertinney Hill in St. Just, and on the northern edge of Dartmoor, not far
from Oakhampton. A third variety is formed of a conglomerate of
large crystals, and frequently in a state approaching disintegration. Much
of this is seen in St. Just, and at Stenna-Gwyn in St. Stephens, St. Austell.
A schorlaceous variety constitutes the fourth. It is abundant in St. Just and
Sennen, and is extensively scattered over various parts of Cornwall and
Devon.
The following remarks, derived from Mr. J. Carne, place the rocks
of St. Just and their relation to the mineral veins in a very satisfactory
view: "The Granite ridge or junction takes place at Cape Corn-
wall, and continues through St. Just district, where it is plainly to be
seen again at Pendeen fishing cove, the distance of two miles, and at
the Gurnard's Head and at Wicca Pool in Zennor. The junction is
nowhere more than half a mile inland throughout the whole district.
The mineral lode, in passing through the junction, generally improves
in value, and frequently very rich deposits of tin and copper are found
following the dip of the Granite, or, as it is termed, riding the junction.
Generally speaking, the Killas in the cliff is a mixture of Clay-Slate, extremely
hard, with patches of Greenstone and Hornblende Slate, denser and of finer
grain where it joins the Granite. Whenever the lodes come in contact with
any of these patches, or cross a course of Greenstone, they invariably become
small and poor, frequently being nothing more than a small leader, just
sufficient to guide the miner, on the course of the lode. When the Killas of
St. Just contains a mixture of quartz and mica it is considered very favour-
able for mineral. The brown Killas is hard, and contains more tin than
copper. The pale blue variety generally accompanies the rich lodes of
copper. The miners apply the word Killas to Clay-Slate, micaceous Slate,
and hornblende Slate if it is soft. Clay-Slate of the hardest degree is, strictly
speaking, true Killas."
"The china stone of St. Stephens," says Mr. Carne, "and other parts
might perhaps be mentioned as another variety of Granite, but scarcely
* Pryce's "Mineralogia Cornubiensis," p. 75. 1778.
+
On the Granite of the Western Part of Cornwall." By Joseph Carne, Esq., F.R.S., &c. (" Trans-
actions of the Royal Geological Society of Cornwall," vol. iii. 1828.)
02
196
[BOOK II.
THE FORMATION OF DEPOSITS.
any of it occurs in the western part of Cornwall, and, besides, it owes its
difference from ordinary Granite to decomposition." The latter portion of this
quotation has been printed in italics for the purpose of drawing attention to
what appears to be a questionable hypothesis.
That china clay and china stone have usually been referred to decompo-
sition-produced by some local cause-must be admitted, and there is a large
amount of evidence which goes to support that view. The felspar of the
Granite is regarded as the constituent most liable to decomposition. In the
neighbourhood of Wheal Coates, St. Agnes, it is not unusual to find the
crystals of felspar converted into china clay, or kaolin, and sometimes the
clay itself is removed and the cavity left is filled in with the black oxide
"
W
87
མཉན་
Fig. 14.-Granite Tor on Rosewall Hill.
of tin. These pseudomorphs are of great interest. They have been occasion-
ally found in other localities, but they are by no means common. A careful
examination of the china clay quarries around St. Austell, and at Lee Moor
on Dartmoor, lead to the supposition that these deposits appear rather to
resemble Granite which has never been properly formed, than Granite which
has undergone decomposition.
The only conclusion to which we can legitimately come with respect to
Granite, is to admit that all known evidence is in favour of our regarding it
as a rock of igneous origin, to a certain extent. The quartz, mica, and
felspar, which may be regarded as the more important constituents of
this rock, were probably at one time subject to a temperature sufficient to
keep the silica and alumina and the alkaline constituents in a condition of
plastic fusion. The Granitic mass was then under enormous (probably sub-
aqueous) pressure, which was maintained for a prolonged period, during
which crystallization was going on, and in this condition it was forced
through the surface rocks of that epoch. The detection by Sorby of mole-
cules of water in the quartz crystals of the Granite, sufficiently proves the
presence of water during the period of formation.
If we examine a section of a Granite quarry, we shall find a structure
which can only be explained by supposing that vast pasty bubbles were
forced through the superincumbent strata. These may be represented by
CHAP. I.]
THE STRUCTURE OF GRANITE.
197
the sketch of actual Granite tors on Rosewall Hill, near St. Ives, and the
accompanying theoretical diagram.
Although this diagram, Fig. 15, must be regarded as being, in the main,
hypothetical, yet it represents the general conditions, which the author has
studied in the Penryn Granite quarries, and in those of the Cheesewring, near
Liskeard. Such masses as B, C, D, D, were sufficiently obvious. The jointed
structure is only such as would be produced in the process of cooling or
hardening a plastic mass. The lines a, a, a, a, are lines of fracture dependent
upon some greater cause, corresponding with the fissures, which eventually,
by becoming filled in with metalliferous or earthy minerals, form mineral
veins. The shaded portion marked A has been observed in several
instances, and the conditions are those which would be produced by the
interference of these Granitic bubbles with each other. The Granite at A is
always more or less disintegrated, and very frequently the space indicated
forms the channel through which the surface waters are drained away.
The quarrymen are quite familiar with this condition of Granite, and
supposing they were working from the point A to the point B, they would
D
B
а
A
Fig. 15.-Hypothetical Granite.
a
α
say they were "gaining the quarry," that is, they found the beds rising in
front of them. After having reached B the curve of the beds was a decline
from them, and this they express by saying they are "losing the quarry." It
will be obvious, we think, to all who have their attention directed to the
Granite tors of the Cornish hills or of Dartmoor, that they all indicate this
curvilinear system of the beds, allowing only for the disintegration due to
atmospheric causes. Dr. Boase noticed this peculiarity in the Cornish
Granites. He says: "Whenever the Granite is exposed by quarries on the
sides of hills, near the junction with the Slate (as at Kit Hill and in the
parishes of Mabe and Constantine), the surface has not only a rounded form,
but is also traversed by curved fissures and joints."
Some years since it was suggested that the Great Exhibition of 1851
should be commemorated by the erection of a monolith of Granite
of not less than seventy feet in length. It was thought that this,
mounted upon a cubical mass of about thirty feet, giving together
a height of a hundred feet, would be an imposing object, and secure
permanence to the spot on which this remarkable gathering took
* A C in Fig. 15, which is copied from one of the Granite quarries in Mabe, is an imperfect por-
tion of the mass formed at the junction of some of the rounded masses, and which will represent that
condition of Granite which is found to be most metalliferous. Captain C. Thomas and Mr. W. J.
Henwood have both drawn attention to the difference between what 'they call "mine granite" and
building granite," D, D. This will be referred to in a future page.
.66
198
[BOOK II.
THE FORMATION OF DEPOSITS.
place. The author of this volume was requested to ascertain if a block of
Granite of the required length could be obtained. The greatest length which
could be obtained was about fifty feet. It was from two quarries only (the
Cheesewring, near Liskeard, and the Lemorna quarries, a few miles west of
Penzance) in Cornwall that such lengths could be got out. All the beds
presented a more or less curved surface.
This condition is very satisfactorily described by the Rev. J. G. Cumming,
of the Isle of Man, from whose book the following extract is made :-
“Now let us examine this great ellipsoidal Granitic bubble. It rises up in
a fine dome, around which mantle a series of metamorphosed rocks," &c.
Baron von Buch, in his description of the Brocken in a paper read before the
Berlin Academy of Science (December 15th, 1842), has given us a good
insight into the structure of these Granitic bubbles The regularly cir-
cular form of Granitic mountains, and the breaking up of the surface into
millions of blocks, seem to depend on one another in some relation. He
suggests that Granitic mountains are lifted up in a certain plastic condition,
not as lava, in a perfectly fluid state, filling up fissures, but in thick
ellipsoidal bubbles, by forces acting from beneath. In the ultimate cooling
and contraction of the upper dome-shaped surface it will necessarily break
up into a vast number of blocks, forming what have not been inaptly termed
'seas of rocks.' At the same time the Granite arranges itself in cooling into
large concentric layers, gradually diminishing in size until at last the inner-
most nucleus appears cylindrical, as may be seen in bosses of small extent,
and this remarkable concentric arrangement may very readily be mistaken
for stratification."*
All Granite rocks are, as far as our observation has gone, intersected by
larger or smaller veins. These frequently put on the appearance of being
Granitic veins, which have been sometimes called contemporaneous. Con-
temporaneous such veins could not really have been. It is quite possible
that while the larger mass was in the process of cooling, there might have
been an injection of matter of a higher temperature, and consequently in a
more fluid condition. Granite veins proceeding from the great central
masses, penetrating the Granite itself and piercing the neighbouring Slate
rocks, are strong evidence that a considerable degree of fluidity must have
prevailed at one time in the erupted mass. It is highly probable that
fissures previously formed may have been filled with the erupted matter, and
that these fissures have been enlarged by the process of crystallization.
Although Mr. Carne himself uses the term, yet his own description—which
is very correct-is directly opposed to contemporiety.
"The observer," he says, "is struck with the frequent occurrence of what
appears to him to be contemporaneous Granite veins, but on a minute
inspection these will generally be found to be veins of quartz, but their
influence appears to have extended to the Granite which immediately adjoins
them; at least, the adjoining Granite is usually of a different kind from that
of the neighbouring mass, although forming one body with it. This
difference in some places extends several inches on each side of the vein,
which itself is not more than an inch or even half an inch in width. If the
*"The Isle of Man." By the Rev. Joseph George Cumming, M.A., F.G.S. 1848.
CHAP. I.
I.]
INFLUENCE OF ROCKS ON DEPOSITS.
199
quartz of the vein is at all disintegrated, the Granite which adjoins it on each
side is decomposed, and this is frequently the case even where there is no
disintegration in the quartz. But decomposition, although doubtless the
frequent cause of the dissimilarity of the Granite, is not the sole cause, for
there are numerous instances in which neither the quartz nor the adjoining
granite has undergone any change, and where this is the case the latter is
much harder than that of the mass which is farther distant from the quartz
vein. The Granite close to the vein is frequently of a red colour, and it
generally contains more felspar and less quartz than the Granite mass near
it. It is possible, therefore, that at the period of the formation of the
Granite the matter of the quartz, instead of combining generally with the
other substances, arranged itself, perhaps by elective affinity (?), in separate
although contemporaneous veins, and in consequence the Granite close to it
contains a smaller quantity."
Mr. Carne, in the paper already referred to, directs attention to some
curious conditions which are connected with the existence of Granite
boulders that are found on the western coast of Cornwall. "The occurrence
of rounded and water-worn masses of stone, of all sizes, in situations where
they could not have been originally placed, is not uncommon.
The
most remarkable circumstance of this kind which is to be found in Cornwall
occurs at St. Agnes Beacon, where, nearly 500 feet above the sea-level, a
layer of sand occurs of the depth of 6 feet, and immediately under it a layer
of rounded stones.
There are, on the western coast of Cornwall,
numerous instances of a similar kind, although none so much above the
level of the sea."
•
Before quitting this division of the subject, it cannot fail to be instructive
to give the expression of opinion of one of the most experienced of
Cornish miners, Captain Charles Thomas, who was at the same time a man
of original views. He says:-
"If a central line, due magnetic east, be drawn from St. Just on to
Tavistock and Exeter, and two other parallel lines be drawn, one north and
the other south of this central line, and six miles distant from it, forming a
zone of twelve miles in breadth, this zone will be found to enclose nearly all
the productive mines of tin, lead, or copper in the two counties. On
Dartmoor, perhaps, this zone may be flattened out a little, but the metallic
deposits there are proportionably diffused, no considerable quantity being
found in any one locality. An opinion has been very prevalent, especially
in the western part of the county, that a lode to be productive should be
situated to the north of Granite. This holds good only to the west of Truro.
The great tin and copper district east of Truro, especially about St. Blazey,
lies to the south of Granite. The great mining zone does not follow the
Granite, but continues in the direction of a right angle to the present
magnetic current. And whenever, in that direction, the great beds of
secondary Granite, compact Clay-Slate, Greenstone, with granular Killas and
Elvan courses are found, there the greatest deposits of copper have been
found. These beds do not everywhere extend to the whole width of the
*"On the Granite of the Western Part of Cornwall."
actions of the Royal Geological Society of Cornwall," vol. iii.
By Joseph Carne, Esq., F.R.S. ("Trans-
1828.)
200
[BOOK II.
THE FORMATION OF DEPOSITS.
twelve miles, but large tracts sometimes occur, of several miles in length,
where the strata are utterly unfavourable for mining operations. The tract
extending from Chacewater to several miles east of Truro may be adduced
as an example. In strata of this character, lead, silver, zinc, and sulphur are
the only ores likely to be found there. The strata north and south of this
twelve-mile zone seem unfavourable for mining operations. Hitherto, at
least, profitable mining has been almost entirely included within that
width."
"For the clearer understanding of the geology of this district," Charles
Thomas compares the "counties of Cornwall and Devon, as far east as Exeter,
to a large flatfish spread out into the sea. Let the west of Cornwall, from Hayle
and Marazion to the Land's End, represent the head, the rest of Cornwall the
body, and Dartmoor and vicinity the chine and tail. Primitive Granite will
represent the backbone; secondary Granite and compact Clay-Slate the
muscular fleshy fibres from the back to the sides; Greenstone and granular
Killas, intersected by Elvan courses, the ribs and softer parts of the fleshy
sides; and the muddy Killas, shelfy Slate, and secondary Limestone, the fins
and belly fat. In the secondary Granite and quartzose micaceous Clay-Slate,
nearest the backbone, are the great deposits of tin; in Granite a little
further removed from the backbone, as well as down the sides in Greenstone,
compact and dark-coloured Killas near Elvan courses, and in light-coloured
and white Killas when granular, will be found copper. Branching off at
right angles from the copper and tin deposits, in the soft flesh of the ribs,
lead will be found. In the backbone itself and the extremities, the primitive
Granite and the shelving Slate, exist excellent materials for walling and
roofing, but no metallic ores to remunerate the adventurer for the toil of
working. One must not conclude from this that no mining strata exist in
Cornwall or Devon beyond the twelve-mile zone, to which the mining
operations have for the most part been hitherto confined. Primitive Granite
in abundance is found about Camelford and stretching eastward towards
Launceston. I am not aware that the ground in that neighbourhood has
been sufficiently examined to ascertain whether secondary Granite, granular
Killas, Greenstone and Elvan courses form its outskirts and fill up its hollows,
as in the existing mining zone. Should it prove to be the case, another
mining district may hereafter be explored by another generation."
In another lecture the same authority,-speaking with all the decision
which has been derived from long experience and always careful obser-
vations,—writes as follows. (It is preferred that those extracts should be
given in the observer's own words. They are the words of an aged practical
miner, speaking to practical miners, and they therefore carry much weight
with them. Captain Charles Thomas was a man of the utmost honesty,
but with strong prejudices; therefore his hypotheses should be carefully
weighed before they are adopted as being strictly reliable.)
"As a considerable portion of our profitable mining operations is carried
on either in or contiguous to secondary Granite, never extending into what
is denominated primitive, although varied in its structure and composition
in different localities, the following are some of the characteristic features of
the productive Granite: fracture rough and irregular, very jointy, frequently
Tein
West
Cross Course
Elvan
Granite
Railroad
South
variantic N
78° 20°W
True North
East
1
1
East
Seton
West Tolgus.
Seton
West
Wheal Seton
East Wheal Crofty
North
Pool
North
Roskear
South
Gustavas
North Crofty
Roskear
Wheal
Agar
CAMBORNE
Stray
Park
しく
​CAR
Confurrowe
EMA
Dot coath
۸۸۷۷
Cook's
Kitalen
-South Fincroft
South Crofty
B
Tincroft
East Pool
Wh. Tehidy
Cambrea
L
LL
L
ㄱ
​Wheat
maid
Athens
1.7
LL4
くじ
​Soutty Carhbrent
L
17
L
L
LAY
L
Pendarves and St Aubyn Consols
West Stray Park
Teazy
Camborne
Crosby Lockwood and CP 7, Stationers Hali Court, London
Trevoole
West Grenville
Wheal Typhena
22
Tolearne
ר
1>
7V
넣고
​L
South Condurrowe
Mul Granille
<
V
ㄱ
​72
고
​^7
South Dolooath
South Threal Frances
درد
اراد
477
तर
י.
West!
Basset
>
7
くてくく
​North, Basset
Wheal Tolgas
Elvan Lere
REDRUTH
ΣΧ
Elvan Lere
•
76
theal Wentworth
Wheal Beauchamp
East
Basset
Wheal
Basset
=27>4=
ALL
MINERAL VEINS, CROSS COURSES
AND ELVANS,
in the District of
CARNBREA AND ILLOGAN.
Compiled from the Geological Survey Maps.
Scale, 2 Inches 1 Mile
-
7
3 Miles
THOS KELL & SON, LITH. 40, KING S? COVENT GARDEN.
CHAP. I.]
CHARLES THOMAS ON LODES.
201
containing hornblende and chlorite, is traversed by irregularly-formed Elvan
courses, whilst portions of it, like ribs, project from the main body into the
surrounding Slate. Its localities are some of the outskirts of primitive
Granite districts, the hollows between high hills, the base of lofty peaks rising
from the interior of such districts, and sometimes rising in such situations
into small hills itself. The configuration of the landscape alone to an
experienced eye would for the most part indicate the position of this kind
of Granite. A narrow margin only of some Granite districts is of this kind,
although a thin layer of it sometimes overspreads pretty large portions of
primitive Granite. The largest extent in this neighbourhood (Camborne) is
found extending eastward from Troon, through South Francis, South Basset,
and Wheal Buller, thence south-east to Tresavean. This Granite at
Tresavean mine, where it forms a junction with the Clay-Slate, is of a great
depth. In tracing it westward it is found to get gradually thinner. At
East Francis, a mile and a half into the Granite district, it ceases to yield
copper. Nine-maiden Downs is on the primitive Granite rock, with only a
very thin covering of the tin-producing Granite. The primitive rock extends
over a large part of Stithians, Wendron, and the south of Camborne, and in
those places no mine of value has been discovered. Passing on to the
south-west of this district of primitive Granite, we again meet with a margin
of the secondary kind, and then we find Wheal Trannack, Wheal Trumpet,
and Trevennen mines. Trumpet Consols and Wheal Lovel are found on the
flats of the same neighbourhood, and Porkellis United, three miles from
Killas, in a hollow between bold hard hills. In this district, as well as
in other tin-producing localities in the interior of Granite ranges, shoots or
ribs from the prominent hills intersect the adjacent country, and coming in
contact with the lodes, render them unproductive. Mr. W. J. Henwood, in his
remarks on the Granite in which Wheal Trannack and Wheal Trumpet are
situated, says truly that where these mines were rich the Granite was coarse-
grained, but becoming at deeper levels close-grained, the lodes failed to
poverty. Between the primitive Granite hills of Godolphin and Tregoning a
portion of secondary Granite occurs, the site of the Great Work mine. Thin
at the top, it deepens eastward to the base, and while it lasts the mine has
been found productive, but on reaching the primitive bed-the continuation
of the adjacent hills—the lodes immediately become poor.
(C
Among other localities of secondary Granite may be enumerated the
whole of Carn Camborne, the west, north, and south parts of Carn Entral,
and the northern part of Carn Brea. This distinction between the two kinds
of Granite as found on the eastern part of Carn Entral, and their limits, by
the form of the surface, can be clearly seen from Dolcoath. From Carnanton
is perceived, with equal clearness, the difference between the body of primitive
Granite of the Entral Hill and the secondary sort sloping down towards the
south, in which Condurrow mine is situated. From near Carn Brea Castle
also can be seen the tops of the secondary Granite, thin at first, and gradually
thickening till it forms a tolerably deep bed at the Carn Brea mines.
“The Carradon Hill, at its south base as well as the west, stretching away
some distance into the Craddock Moor, and filling the intervening hollows,
has also a border of secondary Granite, but getting thinner and thinner as it
202
[BOOK II.
THE FORMATION OF DEPOSITS.
recedes from the primitive hill, until the rock, without any sign of metallic
life of value, fills up the rest of the district. This diminishing thickness of
secondary Granite was clearly shown in the St. Clear mine, situated on the
low ground west of Craddock Moor. At the surface, consisting of secondary
Granite, the lode was very large, containing a large quantity of gossany
matter. The primitive rock, however, was soon reached, and the lode found
split into innumerable strings, leading to the abandonment of the mine.
Phoenix mine, situate at the foot of the Cheesewring, but not productive
westward in the primitive rock of Granite, is another case in point.
"Another example of secondary Granite, under similar circumstances,
occurs on the east side of Rosewall Hill, sloping down towards St. Ives.
Rosewall mine, situated half way up the hill, was rich in tin while the lode
continued in the upper covering, but on reaching the primitive rock it failed,
and became worthless. St. Ives Consols is in a deep bed at the base of the
hill.
"As productive Granite commonly occupies the base of lofty hills and the
margin of some extensive Granite districts, so the bold prominences and
unbroken central portions may be safely assumed to be essentially of a
primitive character. The principal hills and districts of this kind have been
already named in pointing out the localities of productive Granite. Among
other hills of the same kind, in the west of Cornwall, may be named Castle-
an-Dinas (north of Penzance), Carn Menellis, and Carn Marth (at Gwennap
and Wendron); in the eastern part, Brown-Willey, Rough-tor, and Kit Hill.
Primitive Granite, when not bordered by secondary, usually passes gradually
into other substances. Sometimes crystalline quartzose rock intervenes
between it and the Clay-Slate. Such is the case between Tregoning Hill and
the Clay-Slate at Wheal Vor. At other times schorlaceous rock (schorl and
quartz) occupies that position. Instances of this kind occur on the out-
skirts of Dartmoor, Brown Willey, Carn Menellis, east part of Carn Brea,
and Land's End. Roche Rock is composed of this substance.
"Primitive Granite may be further distinguished by the perfection of its
character, if I may be allowed so to express myself, composed chiefly of
quartz, felspar, and mica, or talc. It contains no heterogeneous matter like
the secondary kind, having no hornblende or other ingredients intermixed.
The crystals of felspar are also more perfect than in the secondary kind, and
being less jointy it may generally be split with smoother surfaces. The
ideas suggested by its structure, as well as by the lofty hills and unbroken
plains formed out of it, are those of substantiality, firmness, immovability,
just such as we might expect it to be coming fresh from the hands of the
Creator; exhibiting in the mass no signs of disturbance by the elements, no
rendings nor upheavals by earthquakes, &c.
"After many years' experience and careful observation, made in all the
mining districts of Cornwall and Devon, I have come to the conclusion
that the two kinds of Granite which I have distinguished as primitive and
secondary differ as much in many respects as Granite and Elvan; that
primitive Granite contains no metallic ores of value; that tin ores are found
nearest to it, and copper ores of value never in it, nor very near to it. In
secondary Granite, where lodes of suitable size, character, and direction
CHAP. I.]
COLOUR OF ROCK FORMATIONS.
203
occur, some of our most valuable mines have been found, and others may
be looked for.”
This quotation, from a lecture by so very experienced a miner as Charles
Thomas, will convey a correct idea of the generally received hypothesis of
mineral lodes.
The metalliferous character of the mineral lodes are, it is supposed by
many observers, to be determined by the mechanical structure of the neigh-
bouring rocks,-by the position of these rocks,-and by their chemical
composition. Granite, Slate, and Elvan are the metal-inducing strata of
Cornwall. Their hardest portions are always quartzose, and these indurated
portions are rarely of any value for mineral deposits. A fine-grained
Granite rock, such as is called Whet-stone,-is an unfavourable indication for
metallic deposits. That of a coarser texture, containing large, well-developed
crystals of felspar, is equally of an uncongenial nature. If the Granite rock
be of a medium character, being neither very fine nor particularly coarse-
grained, and the imbedded felspar be of a greenish or brownish hue, and the
planes of the crystals rather indeterminate, the character of the rock is con-
sidered to be a favourable one. If the basis of the rock consists of a pale,
greenish felspar, with quartz and mica, and occasionally schorl, the lodes
passing through it may be regarded as giving fair expectations for being
productive of tin.
A thickly lamellar brownish-purple Slate rock, which exists around Carn
Marth, is traversed by the lodes, which always contain copper, and frequently
tin also. A Clay-Slate (killas) of a pale greyish-yellow hue, passing into a
dull white, and here and there marked between the lamina with a few bluish
spots, with internal lamellar structure, but in a state of decomposition,
accompanies the richer portions of the copper lodes of Cornwall. Al-
though copper lodes have been productive in this pale-coloured slate, when
they pass through it into a deep blue quartzose Killas, the mineral deposits
either dwindle gradually away or suddenly disappear.
Mr. Henwood is impressed with the idea that the colour and cha-
racter of the rocks materially influence the mineral nature of the lodes.
He says: "Pyrites are found in a dark blue Clay-Slate, homogeneous in
texture, of a glossy and silky lustre, having a very even lamination, and
opening in thick horizontal joints, which coincide with the cleavage planes.
In this rock the lodes seldom contain tin ore. If the Slate assume a deeper
hue, the copper ore which the lodes may have previously yielded are re-
placed by iron pyrites, and if the rock becomes quartzose, even the
iron pyrites disappear." This agrees entirely with my own observations,
but it is exceedingly difficult to offer an explanation of the causes which
lead to these remarkable changes. The Slate, wherever tin ore abounds,
is of a tolerably uniform character, thick bedded, and blue, with an oc-
casional greenish tinge (this is almost always produced by the percolation
of water charged with decomposing vegetable matter, or impregnated with
carbonic acid). Its diminution in the depth of colouring, and a softening in
the texture of the rock, are usually unfavourable signs.
In the greenish and blue varieties of Slate but few lead lodes occur, and
these are generally at no considerable distance from the Granite.
204
[BOOK II.
THE FORMATION OF DEPOSITS.
"Whether the rocks are Granite, Elvan, or Slate, when the joints which are
parallel to the lodes in their directions fall towards the lodes in descending, it
is considered a favourable indication; whilst, if similar joints separate from
them as they go downwards, it is considered an index of poverty. In
all these cases many transverse joints seem to exercise an unfavourable
influence on the produce of the lodes, and often a course of ore is directly cut
off by a joint running across the lode. In all cases I believe this can be
shown to be the result of mechanical disturbance" (Henwood).
Mr. Henwood truly remarks that the cleavage planes of the schistose
Slates are almost invariably curved and contorted whenever the rock is
quartzose, and in such cases it is usually very fissile, and the laminæ are
highly inclined. Either of those conditions is accounted inauspicious.
When the cleavage planes are regular and moderately inclined, and when
the rock exhibits a thickly lamellar structure, the lodes which traverse
it may be expected to be productive.
Professor W. W. Smyth's address, delivered before the British Association
at Plymouth, in 1877, on "Physical Phenomena connected with the Mines of
Cornwall and Devon," should be consulted as one of the most compendious
statements published on this interesting subject.
When the consideration of the mineral veins of this district is reached, it
will be shown that there is evidence that several hundred feet of the surface
have been removed, and from this, in all probability, the detrital of tin
of Trevaunance, of Perranzabula, and other districts
have been derived. It therefore becomes important to
indicate the evidences of these great disturbances. The
clay-pits and the beds of sand worked around St. Agnes
Beacon furnish that evidence in a very convincing form.
Two examples are therefore given. The first figure is a
correct section of one of those clay-pits. Above the line
where the woodcut commences there exist twelve feet of
fire-clay, and ten feet of overburthen, consisting of
earthy and decomposed peaty matter.
f
In this clay (Fig. 16) large masses of the neighbour-
ing rocks are found imbedded. In Fig. 17 we have ex-
posed a fine section of the rocks of an old sea-coast.
This was brought to light by extensive workings for tin,
which were carried on for some years. Resting upon
the rock (4), and dispersed through the clay resting upon
it (3), were numerous blocks of slate and granite, some
of them water-worn, but some still preserving their
angular edges. Above this there was a considerable
accumulation of sands (2), of varying degrees of fine-
ness, and earthy deposits (1), with various kinds of
decayed vegetable matter, up to the surface soil (5).
From Cape Cornwall southwards, near the commencement of the Granite
coast, the boulders begin, and extend, varying much in their thickness,
around Land's End. At Portnanven Cove, in St. Just, are two beds separated
from each other by a mass of solid Granite. The western bed is 10 feet
Fig. 16.-Clay-pit at
St. Agnes.

CHAP. I.]
ANCIENT SEA COAST.
205
in thickness and about 80 feet long. The eastern bed is at least 200 feet
long and 20 feet thick. At Wheal Oak point a Guide-a name given in
the St. Just district to an iron lode-occurs. It is about 6 feet wide,
and in it many boulders are found. Several other examples might
be referred to, but these appear sufficient for our purpose. At Wheal
Carn mine, at the height above the level of the sea of at least 500 feet,
the miners in clearing out an old shaft passed through a bed of boulders
of a thickness of about 15 feet. In the tin lode of Ding Dong mine, in
Gulval, near Penzance, numerous rounded pebbles were found in the lode.
And at Relistian mine a mass of pebbles was discovered in the tin vein
about 12 feet square. These facts, and many similar which might have
been quoted, serve to show that the filling of the fissures was more recent
than the disintegration of the Granite.
At Tol-Peden-Penwith,-or, as it is sometimes called, the St. Leven Land's
16
4
Fig. 17.-Old Coast at St. Agnes.
End,-are some fine examples of Granite lodes piercing the Granite mass.
These are usually of a finer grain than the mass itself. They generally vary in
colour, and appear to affect the Granite through which the vein has pene-
trated. Sir Henry de la Beche, who gave much attention to the phenomena,
says: "The veins are merely joint or divisional plane fissures, filled by
quartz or other mineral substances, which are seen in the continuation of
the same or similar fissures in the mass of the adjoining Granite." The
penetration of those Granite veins through the Slate (killas) show very
clearly the conditions under which they were formed. The following plan of
a set of Granite veins on St. Michael's Mount, Fig. 18, is by De la Beche.
The shaded portion is Slate; the Granite veins are marked a a a, and bb is a
joint fissure with a general direction about east twelve degrees north, west
twelve degrees south, traversing both Granite and Slate, the amount of
separation of the joint, combined with the course of the veins, having
206
[BOOK II.
THE FORMATION OF DEPOSITS.
produced the appearance of a slight heave of the rock through which it
passes; d d is a smaller joint fissure parallel, or nearly so, to the larger ỏ b
a
α
a
a
a
Fig. 18.-Granite Veins, St. Michael's Mount.
d
b
a
filled with mica where it traverses
the slate, but containing more
quartz, and being altogether filled
with that mineral, where the joint
fissure traverses the Granite veins.
The following example of a
Granite vein traversing a Slate rock
is drawn from an original survey by
the late Mr. Thomas, whose name
is associated with some of the best
Mining maps of Cornwall (Fig. 19).
It may appear that more atten-
tion than was necessary has been
given to the Granite veins and the
evidence of disturbance shown by
the boulders collected in beds and caverns, but it will be seen that these
phenomena have a peculiar relation to the "Elvan courses," as they are
called, which have certain special bearings on the question of mineral lodes.
SCALE ABOUT 20 FMS ΤΟ I INCH
Fig. 19.-Granite Veins at Trewavas Cliff.
ELVANS.-The relation-or the supposed influence of this rock on the
mineral veins-is so marked that it demands especial notice. The following
notice from Pryce shows how the old miners regarded this rock: "Elvan at
a shallow level is a gritty stone, most like a coarse freestone, but in
depth is exceeding hard. The two most common colours of this stone are a
bluish grey and a yellow freestone. It commonly yields great quantities of
water, and we take it to be of the same kind with that stone which lies on
the culm veins in Wales. It sometimes runs in a direction north and south,
contrary to the metallic veins, which generally keep their course through it,
but the lodes are frequently squeezed up by its accompanying them some
length in their course, or are split into many small branches. Sometimes
the fissures or lodes are thrown short on one side, out of their direct course
as it were, by the extreme hardness of this stratum, and afterwards they
recover their course again. At other times the metallic veins are elevated
or depressed by it, though they always recover their former direction, and
unite again, for this stratum wears out at a great depth and is succeeded by
Killas." (This is illustrated in Fig. 20.)
Our future remarks will show how much at fault this author was in his
hypotheses. We find in addition to the true Granite veins long lines of
Granitic and felspar porphyry, to which the term of Elvans has been given.
CHAP. I.]
ELVAN COURSES AND COPPER LODES.
207
They are found traversing both the Granite and Slate in a continuous body,
and in their mode of occurrence remind the observer of Trap-dykes, and they
differ from them only in mineral composition. "Those Elvans," says Sir
Henry de la Beche, "which traverse the Granite and Slate are of an age
posterior to the consolidation of at least that portion of the Granite which
they cut through. With respect, however, to those which only traverse the
Slate, the time of their formation, or rather the formation of the fissures
into which the igneous matter of which they are composed was injected, is not so
clear; some may have been
formed at the epoch of
the intrusion of the great
masses, while others may
even have been produced
after the Elvans which
traverse the Slate and
Granite."
There is a want of the
usual clearness which al-
ways marked the deduc-
tions of De la Beche in
these remarks. This arises
from his holding the view
that fissures were pre-
existing, into which the
pasty mass of the Elvan
was projected. All the
conditions of the Elvan
courses rather point to the
forcible injection, under
very great pressure, into
the already solid rock,
producing thus, as shown
in our section of Granite
veins, a peculiar tendency
to an arborescent form.
W. HRSEY
LOD
Be this as it may, we
gladly quote his descrip-
tion of the more important
Elvan courses of the West
of England.
18 FMS
BUJIA'S
LODE
BUSIA'S SHAFT
50 FMS
SAMPSONS SHAFT
401
TIDDY'S LODE
BR
CQUR
100
112
130
155
KENTS
LODE
MELLETTS LODE
MORCOM'S SHAE
Fig. 20.—Elvan Courses and Copper Lodes.
"These Elvan dykes vary from a few to 300 or 400 feet in breadth, and
though comparatively narrow, may even be traced satisfactorily for several
miles. One of the longest hitherto discovered is that which runs from Wheal
Darlington, near Marazion, for twelve miles by Wheal Fortune, Corbus,
Treganhorn, Cayle, Herland mine (near Gwinnear), Roseworthy, and Cam-
borne to Pool, sending off a branch near Cayle about five miles long, which
passes by Carnhell Green, Cassawson and Tregear into the Carn Brea
Granite. How far this Elvan may extend to the south-westward it would be
208
[BOOK II.
THE FORMATION OF DEPOSITS.
difficult to say. That which runs along with Penzance pier and is continued
by the Wherry mine is not far out of the line.”*
For an exact description of all the more important elvans, the reader is
referred to De la Beche's Report on Cornwall and Devon, which, studied
with the assistance of the maps of the Geological Survey, will give all the
information which can be required. A remarkable group of Elvans is repre-
sented in the accompanying woodcut, Fig. 21, extending from Redruth over
the well-known mining parish of Chacewater.
These Elvans have a common mineral character, being generally com-
posed of a felspathic or a quartzo-felspathic base, containing crystals of
felspar and quartz, and sometimes schorl. Many of these Elvans are used
REDRUTH
О
PENANCE
CRANITE
201
'ELVAN COURSES
am
S
DAY
CHACEWATER
MINERAL LODES
FAULTS
Fig. 21. Elvan Courses around Redruth.
extensively as building stones, for which purpose they answer admirably,
as they are found to resist atmospheric influences, and to endure for long
without change.
"By Elvan," says Mr. Henwood,† "I intend a rock possessing the
same constituents as Granite, which, as in that rock, vary in their numbers
and proportions, of which the structure is always porphyritic. It is always
a subordinate rock, passing indifferently through all others in the metal-
liferous districts, and may be denominated a vein or dyke according to its
size, which is extremely variable."
* "Report of the Geology of Cornwall, Devon, and West Somerset." By Henry de la Beche,
F.R.S., &c.
"The Metalliferous Deposits of Cornwall and Devon." By William Jory Henwood. 1843.
CHAP. I.]
THE CHARACTERISTICS OF ELVAN.
209
Elvan courses are in general east and west, and north-east and south-
west, the average being about twenty degrees south of west. Some few
run several degrees northward of west. Elvans dip generally from forty to
sixty degrees, and they incline more frequently to the north than to the south.
The Elvans traverse Granite and Slate alike without interruption, and
their character varies with the rocks through which they pass. In Slate
they generally consist of a compact base of felspar and quartz. In Granite,
Elvans are usually of the same materials as that rock, but in different
proportions, and varied in aggregation.
Innumerable joints traverse the Elvans in all directions, dividing them into
small, irregular-shaped blocks.
Plumbago has been found in isolated masses in the Elvans, and rarely,
copper pyrites. Many of the Elvan courses have been worked for the tin ore
they contain.
*
Werner characterises the Elvan as an intimate mixture of dense or com-
pact felspar, in which a little quartz may be occasionally seen. Some
specimens, he says, have a close affinity to the thon-schiefer of the Swedes.
Mr. Hawkins submitted various specimens to Werner. He describes them
in the following order.* The globules on the Chyanoweth Elvan consist of
quartz and mica intimately mixed. This together with the Elvan from
Peden-avonder in Sithney are a fine veined variety of Granite. The Elvan
from Porkellis, Bal, and Breage is the same, but the felspar is decomposed.
The Elvan from Polgooth is an argillaceous porphyry. The Pentuan stone
is common porphyry.
The Elvan dykes extend through Cornwall into Devonshire, and may
be traced in Lundy Island. De la Beche thinks the Granitic rocks of
North Devon are "patches or parts of dykes, analogous to the Elvans
of Cornwall and South Devon, and may have been ejected, like them, after
the sedimentary rocks they traverse have suffered great contortions and
displacements."
It will be seen that the Elvans of the Gwennap district (consult the Map)
all run in a similar main direction, from the north of east to the south of west,
and that all the mineral lodes of that neighbourhood have a near approach
to the same. In some cases strings of black tin and pyrites are found within
the fissure of the Elvan dyke, and occasionally small patches of mineral
matter have been found in the Elvan itself. De la Beche informs us that an
Elvan which cuts through the Old Mulvra mine in its course from Trelyon
Mill, near St. Stephens, to Flat-point Rock, in St. Austell Bay, holds nests.
of yellow bisulphuret of copper, apparently isolated, and varying from several
tons to a few ounces in weight. Plumbago was found in small nuggets by
Mr. Robert Were Fox in one of the Elvans near Devoran, in Falmouth
Harbour; and Mr. J. S. Enys gave the author of this volume a small piece of
plumbago, one of several, found in an Elvan running through his property at
Enys, near Penryn. When we arrive at the consideration of the phenomena
of mineral veins, the conditions under which they are relatively found will
be the subject of attention.
* "On the Cornish Rocks." By John Hawkins, Esq. ("Transactions of the Royal Geological
Society of Cornwall." 1822.)
Р
210
[BOOK II.
THE FORMATION OF DEPOSITS.
A large bed of Elvan interspersed with killas traverses Coisgarne Downs,
extending from the north part of United mines, to the south part of
Wheal Virgin, and eastward through the downs, being probably connected
with veins from the east and west. In many of the mines are found irregular
masses of Elvan of different degrees of hardness, scattered at various depths,
no indications whatever of those Elvans appearing on the surface (Figs. 20, 21).
Elvan courses are often of considerable width, and they have been termed
by the miners courses or channels, to distinguish them from veins. They are
usually composed of hornblende, quartz, and felspar, and may be regarded as
an hornblendic porphyry; but the term Elvan has been applied by the miners
to rocks which differ materially from each other. Elvan in many cases becomes
a vein stone. In the Wherry mine the lode, or Elvan course, was so rich in
tin that it was named "stannified porphyry." At Wheal Unity the Elvan
was so rich in tin as to be regarded as the tin lode. The Elvan course at
Budnick carries at its side a small vein of tin.
Tin lodes are in general richer, or poorer, in Elvan than in the adjoining
rocks in proportion to the hardness or softness of that rock. In Rosewall
Hill, near St. Ives, where the Elvan was hard, the lode became poor. In
Wheal Vor, near Helston, where the Elvan course was soft, the lode improved.
Copper lodes are generally as rich, and often richer in the Elvan than in the
Slate or the Granite, as at Treskerby, Wheal Alfred, and Nangiles. At
Tingtang the lodes were richest when between the Slate and the Elvan.
Elvan courses have been frequently considered as contemporaneous with
their enclosing rocks, simply because they are traversed by metalliferous and
other veins; but this only shows that the Elvan existed before the vein which
passed through it, but when the vein passes by the side of or along the length
of the Elvan course, they may probably be contemporaneous.
Elvan is sometimes found in floors, like the dunstone of Derbyshire,—as in
Crumear and in Penberthy crofts, and in bunches, as in the United mines and
Wheal Squire. There is no way of accounting for these bunches but the
ejection of the plastic material, or by a separation while the course of Elvan
was in a soft state, and its then getting surrounded with the alluvial Slate
deposit.
Mr. J. Carne supposes Elvan courses to be true veins, and he argues in
favour of their being of posterior formation to the adjoining rocks.
1. That they do not always underlie in the same direction, and scarcely
ever at the same angle, as the dip of the Slate. The Elvan course at the
Wherry mine underlies north; the Slate dips south-east. At Cligga Head
the Elvan courses underlie northward, but the Slate dips rapidly towards the
south.
2. In the copper mines of Tresavean and Treskerby the Elvan course is
partly in Slate and partly in Granite.
3. Fragments of Slate are found in Elvan courses close to their walls
(sides) or their junction with the Slate country.
4. The Elvan course in Polgooth mine, near St. Austell, heaves all the
veins which it meets with, except a flukan vein, by which it is itself heaved.
The direction of Elvan courses is generally between east and west, and
north-east and south-west; the average being, according to Henwood, about
CHAP. I.]
RELATION OF ELVAN COURSES TO LODES.
2II
twenty degrees south of west, several of them bearing some degrees to the
northward of west. They more generally incline to the north than to the
south, but in direction and dip they undergo many flexures.
The Elvan courses traverse Granite and Slate alike, but their character
varies with that of the rocks through which they pass; and in the Slate series
they vary more than they do in Granite. A spheroidal structure is common
among Elvans, and large portions, which have no other distinguishable
difference, often take this form, and are separated from the surrounding
parts of the same rock by concentric bands of a ferruginous mineral, often
decomposed into a clay.
Elvan courses have been worked in various places for metallic minerals.
At Wherry mine, Parbola, Relistian, Wheal Vor, Polberrow, Budnick, Wheal
Coates, Polgooth, and
other mines the body
of the Elvan has been
removed for the tin
ore found in it. Gene-
rally the Elvan has
been penetrated by
the tin, but at Wheal
Vor, White Works,
and at
at Polberrow,
irregular and uncon-
nected masses of tin
ore were distributed
through it.
Elvan courses
often intersect mine-
ral lodes. Mr. Mi-
chael Williams gave
it as a general law,
especially in the
Gwennap district,
that a lode is seldom
or never rich, after it
has passed through
HEW SHAFT.
170 FIS
194 FKS
208 FMS
220 FIAS.
200.
HOT
LODE.
NORTH
180 FMS
3700KW
LODE.
HAWKES
SHAFT.
155 FMS.
170 FIAS.
WADE
SOUTH
LODE
Fig. 22.-Elvan Course obliterating Lodes.
an Elvan course in descending; and he gives as an example of this, the
accompanying section of the lodes (Fig. 22) which pass into the great Elvan
course of the United mines in Gwennap-where two of the lodes are lost in
the Elvan at about 208 fathoms from the surface, and the great "Hot lode"
is completely extinguished by it, at a little below the 230 fathoms.
Mr. Thomas,* on the contrary, states that copper lodes sometimes prove
very productive in traversing a course of soft Elvan, which was particularly
the case at Nangiles mine; but in courses of hard Elvan the lodes generally
run very small and poor, and many lodes, particularly tin lodes, split into
small branches.
* "Report on a Survey of the Mining District of Cornwall, from Chasewater to Camborne." By
Richard Thomas.
1819.
P 2
212
[BOOK II.
THE FORMATION OF DEPOSITS.
There is an established belief that the Elvan courses act favourably upon
the mineral lodes running parallel with them-but we have no very satis-
factory evidence in proof of this—and the question demands a very close
investigation. It will be seen as we proceed, that the Toadstone of Derby-
shire and the Whinsill of the northern counties present in some respects.
a close analogy of the Elvans of the western one. They are evidently
igneous rocks, and they often appear to influence the productiveness of a
mineral lode, and are themselves under some circumstances the bearers
themselves of metalliferous ores. A remarkable example of the intrusion
of Elvan courses amidst a set of most productive copper lodes is shown in
the woodcut of a portion of the United mines in Gwennap (Fig. 20).
GREENSTONE, called also Freestone or Irestone, is thus described
by Pryce: "It is by much the hardest of all strata, and borrows its
name from its extreme hardness, and not because it contains iron. It is
of a bluish colour, and usually so hard that it must be wrought with steel
borers and then blown by gunpowder. It often keeps a course east and
west like a lode, but is commonly very wide, and therefore it is very tedious
and chargeable where an adit must be driven across through it. It is this
stratum that is uppermost through great part of the middle of Camborne and
Illogan parishes, where many principal copper mines are enclosed in it.”
In this Pryce is singularly wrong, as will be shown by the woodcut
at p. 213, Fig. 23, which is copied from the Geological Survey Map of
Cornwall.
This remarkable group of Greenstone rocks, extending from St. Erth,
near Hayle, through Gwinnear up to near Camborne, requires some attention.
Stretching from St. Erth in a north-easterly direction towards Camborne—
as will be seen by studying this map-there occurs a remarkable series of
Trapean or Greenstone rocks. This rock, which is extensively worked on
account of its exceeding toughness, and broken as a stone for roads, is
confined, or nearly so, to the Slate rocks. A large Greenstone course extends
from Camborne through Tuckingmill to Treleigh (north of Redruth), at
which places large blocks of stone are lying on the surface, and may
be seen in the open pits at South Roskear mine. This course appears
to hold a regular direction, often the same as the lodes. Three large
courses of this rock run from St. Erth, through Gwinnear on towards Cam-
borne, the direction taken being from south of west to the north of east.
Similar masses are found appearing about midway between Marazion and
Penzance observing the same direction, until at about a mile westward of
the latter town the Greenstone suddenly curves to the southward, as if its
flow had been intersected by the great westerly mass of Granite, and turns
round to the east at Newlyn, and then taking a south-east course passes into
the sea at Penlee Point, in the parish of St. Paul. No Greenstone appears
between Penzance and the Land's End, but it forms the face of the cliff at
Botallack Head in St. Just and the Gurnard's Head in Zennor. The
picturesque character of the coast in St. Just and in Zennor is mainly due
to the interstratification of the Greenstones and the Slaty rocks, and large
masses occur at St. Ives. Mineral lodes are found abundantly in the
Gwinnear and Camborne Greenstone districts (see Map). Very few indications
CHAP. I.]
GREENSTONE ROCK AND VEINS.
213
of veins of metalliferous minerals occur in the Penzance district, and not
many in the Greenstones of St. Ives. Conybeare,* in his paper pointing
out the general mineralogical difference between the rocks of North Devon
and those of South Devon and Cornwall, divides those rocks into-
Metalliferous, or, more strictly speaking, cupriferous and stanniferous
Slate, including various porphyritic and felspathic rocks (elvans), and occa-
sionally Greenstones. This he terms the inferior Slate.
Slate which he terms superior, contains no Elvans, but abounds much
more in Greenstone, especially its obscurer varieties. Conybeare continues
his definition of the rocks in the Grauwacke series; but, as it is not intended
STIVES
BAY
HAYLE
O
PHILLACK
SHILL
IM
எ
NNEA
ZAIGRANITE
CREENSTONE DYKES
ELVAN COURSES
MINERAL LODES
FAULTS
Fig. 23.-Greenstone Rocks from Hayle through Gwinnear.
that this treatise shall deal with geology beyond its connection with mining,
it is not thought desirable to quote this geologist further.
The Trap or Greenstone rocks of Western England are usually intrusive
in the Slate rocks or the ordinary "Killas" of Cornwall.
Dr. Boase † gives the following description of the Cornish Green-
stones:
"A basis of compact or granular felspar, variously combined with horn-
blende in different proportions, sometimes the one and sometimes the other
* Conybeare, "Memoranda relative to Clovelly." ("North Devon Geological Transactions," vol. iii.)
"On the Geology of Cornwall." By Henry S. Boase, M.D. ("Transactions of the Royal Geolo-
gical Society of Cornwall," vol. iv. 1832.
214
[BOOK II.
THE FORMATION OF DEPOSITS.
predominating in the mass. This rock when decomposed produces a
reddish soil.
"Sienetic Greenstone occurs at Davidstow, near Polliphant.
"Hornblendic Greenstone.-St. Clear, Tolcarne, near Penzance.
"Compact Greenstone.-Treneere and around Penzance.
"Lamellar Greenstone.-Rosecradock, St. Clear, Botallack.
"Schistose Greenstone.-Adjoining all the last.
"Argillaceous Greenstone.-Liskeard.
"The compact and schistose Greenstones repeatedly pass into each other,
so that in traversing them from the Granite they appear to alternate; but
this does not hold good to any great extent in the length of their beds, as
may be seen on the shores of the Mount's Bay, where the massive rocks are
insulated in the body of the Slate. Greenstone often gradually passes into
rocks which are for the most part soft and thick lamellar Slates of various
shades of blue and green. They contain beds which are compact and earthy,
differing only from the Slate in which they are imbedded in wanting the
schistose structure, and they abound in metalliferous veins, the matrix of
which is composed of quartz and dark grey crystalline chloride. The quartz
is sometimes much intermixed with felspar; which, decomposing into a white
clay, renders the whole of the lode friable."
It should be noticed that under the general term of Greenstone many
different varieties of hornblendic rocks are included. Many of these forma-
tions around St. Just may be strictly said to be hornblendic. They are
sometimes very compact but often slaty, and in the neighbourhood of Cape
Cornwall we find curious alternations of purely hornblendic with slaty rocks.
They contain in different parts (besides hornblende) quartz, felspar, chloride,
and other minerals. So similar are they that even Mr. J. Carne, than
whom there was no better observer of the Cornish rocks, says: "I have given
the name of Slate to the whole, although they have of late frequently been
called Greenstone. The Slaty rocks in general have a better title to the name
of Greenstone Slate, or hornblende Slate, than to that of Clay-Slate. Green-
stone, however, is a word whose application is becoming almost as general as
that of Grauwacke was some years ago.
It is not unusual to find in the small fissures of Greenstone thin layers of
native copper. This has, on several occasions, led to a belief that copper ore
might be found in quantity at depth, and several mining adventures have
been the consequence. In the mass of Greenstone at Penolva, St. Ives, a
shaft was sunk and an engine-house built; and again in the romantic rocks
known as the Tower of Babel, on the western side of Porthmere Beach, and
extending on to Clodgy Point, considerable mining operations have been
carried on, but nothing of consequence has been found.
KILLAS or CLAY-SLATE.—This term is applied almost universally
to the Slate rock found in the mining districts of Cornwall. Mr. Carne
says, in a note to his paper on the mineral productions of St. Just:
"Show a miner primite Clay-Slate or transition Slate, or micaceous Slate,
or grauwacke Slate, or hornblende Slate, if it be not very hard, and he
*Carne, "On the Mineral Products of St. Just." ("Transactions of the Royal Geological Society
of Cornwall," vol. ii. 1822.)
CHAP. I.]
DEFINITION OF "KILLAS.”
215
will call the whole Killas." The word was no doubt introduced into Corn-
wall by the German miners who settled in that country at the time of
Queen Elizabeth, and who for a long period held possession of its tin mines
and certainly worked a few copper mines.
Killas, which comprehends the whole of the district on the Geological
Maps from Penzance to Davidstow on the north-east of Cornwall, and to
Newton Bushell in Devonshire on the south, and which is coloured with
the tint adopted for the New Red Sandstone, now called Devonian, is the
natural stratum of the metalliferous beds of the West of England.
The definitions given by Pryce, "Of the Strata of the Earth," &c., are
valuable as showing the ideas of the miners of his time (1778) of this peculiarly
metalliferous rock Killas, or Clay-Slate. "Of Killas I have observed six sorts
common to us, the white, the red, the yellow, the brown, the cinerous or
bluish, and the deep blue. The first is very white and tender, and from its
exceeding tenderness is called Fair Ground. It requires much timber and
boards for binding and securing it from falling in the mine and endangering
the workmen's lives. The red is not so fair, but is well disposed for
copper or tin lodes, the latter preferably. The yellow is but indifferently
disposed for either. The brown, which has various shades of lighter and
deeper colours, is generally a hard stone, and contains lodes of tin more
commonly than copper.
"But of all the Killas the cinereous or pale blue is most desirable as the
enclosing stratum of a copper lode. We find it the most common and agree-
able chest that encloses our cabinet of jewels. . . . . It is this kind of Killas
which we call Feasible ground, i.e. to be easily broken, yet firm enough to
stand without the support of binding with timber and boards.
"A Killas in its best state is soft, tender, fleshy, and fatty, which will cut
to any form underground, and requires no timber; but if it is hard and
untractable, and works in very small shreds of stone, it is unfavourable to
work or enclose metal."
Werner, in 1793, examined a series of specimens from Cornwall, and
he expressed no doubt that the metalliferous rock of that county, the
Killas, was a genuine thon-schiefer or argillaceous Slate, differing in no
respect from that which occurs in Saxony.
In Cornwall the term Killas is applied to every member of the Slate'series,
indeed to every rock which the miners cannot identify as Granite or Elvan.
Mr. Henwood says: "It is therefore evident that this name is applied
to rocks of very different characters; as, for example, to the hornblende
Slates and Greenstones of St. Just and St. Ives, as well as to the Clay-Slates
of Gwennap, St. Agnes, and St. Austell. The St. Just and St. Ives Killas
would generally be known in other districts by the designation of Iron
or Ire stone." Experience of many years and considerable familiarity with
the miners of the districts named, lead to a conviction that the Greenstones
were never called Killas by them; it is possible that the hornblendic Slates
may have been so. The term of Irc-stone has been constantly applied to the
Greenstones in all parts of Cornwall.
When near the surface it is usually of a light brown colour and in some
places nearly white; at a certain depth from the surface it becomes full of
216
[BOOK II.
THE FORMATION OF DEPOSITS.
veins of quartz, and at a greater depth it acquires greater uniformity,
becomes much harder, and is generally of a blue colour. It is generally
Fig. 24.-Section of Strata.
Many similar beds varying in
well-known Tintagel Castle.
regularly stratified at various degrees of
inclination. Some of the Killas is in very
hard irregular masses. The section given
in the adjoining woodcut, Fig. 24, is taken
from Trevaunance beach, St. Agnes, where
we have a very fine example of those
three varieties of Clay-Slate. If an observer
carefully trace these beds from the point
indicated, along the coast passing north-
eastward, he will find that the lower, the
blue bed, gradually becomes converted into
cleavable Slate,-until at Newquay some of
the Slate rock of that district is actually used
for roofing slate; and farther east, at Dela-
bole, we find one of the oldest and most
celebrated-Slate quarries in the county.
quality and character are worked near the
In many cases immediately under the soil there appears a compact
stratum of quartz stones two or three inches in thickness (nearly all those
quartz beds have, however, disappeared, and been used as a road material);
under this is a clayey loam of a yellowish colour, about two feet in depth,
resting upon the Killas or upper bed, the superior part of which is generally
in a decomposed or disintegrated state, broken into small pieces, but
becoming firmer as the depth increases. This is the second bed shown,
and is the original source of the quartz stones.
The Killas gathers around the great Granite bosses of the county in
SSE
KILLAS
SCALE OF 15 840
CARNBREA HILL
CRANITE
ROCKS
MINES OF
CARNBREA
x EAST POOL
* W. ACAR
KILLAS
Fig. 25.-Carn Brea District.
the way indicated in the accompanying section of Carn Brea Hill and the
surrounding mining country (Fig. 25).
The lodes of Carn Brea, East Pool, and Wheal Agar are shown, passing
from the Killas into the Granite; the true dips of these lodes being
indicated.
Grauwacke is a Saxon miner's term, and has been applied to a rock
CHAP. I.]
SERPENTINE AND DIALLAGE ROCKS.
217
formation which constitutes the greater portion of that group of moun-
tains known as the Hartz. Werner supposes this rock to have been
deposited during the passage or transition period of the earth from a chaotic
to its habitable state. This appears to be a very loose and unsatisfactory
hypothesis. Can we draw a line of any description, between the chaos and
that order which prevailed when man was supposed to appear on the Earth?
Jameson says grauwacke commences a new geognostic period, namely, that
of mechanical deposition. Mr. Hawkins, in discussing the value of this
name, says :-
"It is now pretty generally acknowledged that the terms 'grauwacke
Slate' and 'argillaceous Slate' are convertible, it being impossible without
the aid of petrifaction to ascertain where the one ends and the other begins.
"A dilemma so unfortunate as this ought to have suggested the proba-
bility of some error in the process of reasoning upon which these distinctions
are founded, and might sooner have led to its correction. . . . . It is surpris-
ing, as the derivative origin of the grauwacke rests so much upon this view
of the subject, that there should ever have been any other opinion in respect
to this order, and that the grauwacke rock, instead of terminating the
formation of argillaceous Slate, should have been regarded as its archetype,
or the point from which it proceeded."
So general is this misconception that the terms "grauwacke" and "grau-
wacke Slate" have been applied without reserve to strata which exhibit in a
very imperfect manner the derivative character-a primitive rock, indeed,
differing in no respect from the argillaceous Slate. The consequence of which
is, that the denomination of grauwacke in the literal sense of the word
has become nearly obsolete.
De la Beche, who examined these rocks with great care, says :-
"In the grauwacke and carboniferous series of this district we find
silicious grains, generally of quartz, cemented by matter which closely
approaches chalcedony or chert, much intermingled with peroxide of iron in
the Red Sandstone of these rocks. In the Red Sandstone series the cohesion
is considerable, and we find the cementing substance chiefly consisting of
alumina, peroxide of iron, and the red oxide of manganese, the rock
being harder when calcareous matter forms any considerable portion of
the cement.
""
SERPENTINE,DIALAGE, TALC SCHIST.-Serpentine rock, which
is especially well shown at Kynance Cove and in the Lizard district, is one
of the most ornamental stones of Great Britain. It has a basis of magnesia,
and derives its colour from salts of chromium and iron. The Lizard district
is made up of hornblendic Slate, Serpentine, Dialage rock, and altered
Devonian. These run closely into each other, and are often not easily
distinguished. Dr. Boase remarks: "The Hornblende Slate of the Lizard is
entirely distinct from that of the other parts of Cornwall, and therefore ought
to be separated therefrom... The transition of this Slate into Euphotide
and Serpentine has been often noticed; but it is more closely allied to
the former, as is shown by its great hardness and by its resplendent lustre.
* "Report on the Geology of Cornwall, Devon, and West Somerset." By Henry T. de la Beche,
F.R.S., &c. Longman. 1839.
218
[BOOK II,
THE FORMATION OF DEPOSITS.
This schist appears sometimes to be embedded both in Euphotide and
in Serpentine, and at other times the latter rock seems to be subordinate to
the schist; but the fact is that all these, although they alternate on a given
line, yet do not long continue parallel, but they mutually abut against
each other; sometimes the one and sometimes the other prevails. Ser-
pentine exhibits a great many varieties, some of which are very hard,
whilst others are so soft as to yield to the nail. This difference appears to
depend on the felspar base, which undergoes several modifications between
a crystalline, compact, and granular state, as seen in the precious Serpentines
in the indurated steatites, and in the common and ollareous Serpentines."
Serpentine is also found at Clicker Tor, near Liskeard. The Polliphant
stone is a variety of this rock or of Elvan. Serpentine must not be regarded
as strictly a metal-bearing rock, but few examples of any mineral ores
having been found within it. The magnesian rocks are rarely metalliferous.
Lead containing silver and copper ore and manganese has been found
occasionally, but in small quantities only.
It is not unusual to find in the fissures of the Serpentine rocks masses of
native copper; these have frequently induced a further search for mineral
treasure, which has never proved very successful. In Trenance mine deposits
of a promising character were found in 1852, and consequently it was hoped
that a profitable copper mine might have been opened out. This hope was,
however, not realised, and the mine was abandoned about 1854. The fine
specimen in the Museum of Practical Geology—which was presented by the
Adventurers—is only a portion of the mass as it occurred in nature, the
miners being compelled to break it to raise it to the surface. The original
piece was upwards of a ton weight.
The Serpentine is frequently crossed by veins of steatite, which was found
in such quantities near Mullion, that, under the name of Soap-stone, it was
sent in considerable quantities to Bristol, and used in the manufacture of
porcelain.
It appears that this may be the most suitable place to introduce a few
remarks on the formation of rock masses in general, more especially
of those which have evidently been formed from alluvial deposits. The
slow and silent processes which have been at work through countless
ages, producing a roofing-slate and probably most of the lithological
phenomena which we have to consider, demand a careful study. Our
information is exceedingly limited, but such as we possess will be found to
bear very importantly on the phenomena which form the chief subject of our
consideration.
If we consider the condition of finely-comminuted sand accumulated in
large quantities, we feel that with moisture, cohesion of the particles
may speedily be brought about, but that in a perfectly dry state this can only
be effected by the prolonged action of cohesive force. Mechanical force,
artificially applied, has been found to be sufficient to produce the coherence of
finely-comminuted china-clay in a dry state, but the degree of consolidation
required for the uses to which the compressed clay is put, can only be
obtained by the subsequent action of fire. In the Potteries this process.
is largely employed in the production of various pieces of earthenware.
CHAP. I.]
THE FORMATION OF ROCK MASSES.
219
Where moisture is present we can scarcely conceive finely-divided detritus
existing long without some agglutination ensuing. The alkaline consti-
tuents of nearly all rocks are soluble to a greater or less degree, and the
water holding them, passing slowly through the masses, affords the cement-
ing materials required. In Granite, Slate, or Elvan, their hardest portions
are almost invariably rendered so by quartz, or some form of silica. These
indurated portions are found invariably to be unfitted for the presence of
metallic minerals. Where lodes penetrate these hard portions of rock they
are usually small, and their contents differ but little from the surrounding
mass. Supposing that the mineral ores found in the fissures are the result
of infiltration, it can be easily understood that those indurated parts would
present obstacles to this process.
Into beds through which water percolates, soluble matter derived from
other rocks may be introduced, and, combining with the constituents, form
new compounds. When these conditions are maintained, especially beneath
the surface of the sea, the saline constituents are subjected by the process
of infiltration to a mechanical separation. It has been shown by Dr. Hoff-
man and Mr. Witt,* that the waters of the Thames, filtered through well-
constructed filtering-beds, lost a considerable portion of the salts held in
solution; and Dr. Normandy † proved that sea water was deprived of all its
salt, by being forced through fifteen feet of sand, or powdered glass. Here we
have evidence of the agent required as the cementing material for the
detrital matter out of which the rock masses are often formed.
Several observers have drawn attention to the influence of hot springs,
coming in all probability from great depths, charged with silica in solution,
and depositing minute quantities of gold and other metals.
Mr. John Arthur Phillips has described with much precision the process
of evaporation going on as these thermic waters approach the surface, and
the deposition of masses of silica and other salts with particles of the
metals, especially of gold, amongst them.‡
In each class of rocks we find variations in the prevailing conditions.
In Sandstones we find the cohesion of the grains of sand very unequal. In
some the cementing matter is as hard as the grains themselves; in others
it is weak, and the rock is friable.
In the Clay-Slate and in the carboniferous series of Cornwall and Devon-
shire there are very marked differences in the conditions prevailing in the
metalliferous and non-metalliferous rocks.
The percolations of silica, in one of its conditions-in solutions through
the rocks-often combined with alumina, lime, and alkalies, will no doubt.
account for the unequal consolidation of the Sandstones and Slates.
The consolidation of mud and clay into Slates is due to causes akin to
those which converted the sands into hard bodies. All these examples of
cohesion probably occurred-at all events were considerably advanced-
before the deposits suffered any considerable disturbance. Even in a state
of repose, it is evident that certain chemical changes were in progress, and
* Report on the Metropolitan Drainage, by Dr. Hoffman and Mr. Witt.
+
Normandy. See "Ure's Dictionary," art. Sea Water.
See "On the Composition and Origin of the Waters of a Salt Spring in Huel Seton Mine." By
J. Arthur Phillips, F.R.S. ("Philosophical Magazine," July, 1873.)
220
[BOOK II.
THE FORMATION OF DEPOSITS.
that crystalline forces were in action, bringing together particles chemically
the same, which gradually assumed a geometric form. The power of bodies
to crystallise freely is shown by the cubes of iron pyrites in some of the
Slates, and the crystallization of quartz in some other rocks. Especially the
double-headed crystals of quartz, commonly called St. Agnes Hail, found
beautifully perfect in the Wheal Coates Granite, are examples of this. The
solution of silica flowed steadily through the sand or mud in dendroidal films;
as the flint consolidated it exerted an enormous pressure, and thus increased
the filmy passage, and formed a small fissure, in which, with yet more force, the
same action proceeded. Small cracks were thus produced, and increased in
size, spreading in various directions, producing eventually a system of quartz
veins, spreading in an excursive manner through the mass. These evidences
show that the sedimentary deposits have suffered considerable modifications
in the condition of their component parts, since they were first accumulated.
That they have been subjected to mechanical forces of an extreme kind is
evident by the violent contortions discovered in those beds, which were
at one time nearly horizontal, but which are now placed at very varied
angles, and in some isolated cases they have evidently been turned over.
This is singularly shown in the rocks around Boscastle and other places in
the north of Cornwall.
The uplifting forces are usually referred to the expansion of the deeper
rocks, under the influence of subterranean heat. This is not a place to
enter into any examination of the hypothesis of central heat, or of the
existence of a fused mass of matter beneath the consolidated rocks, to
which man has penetrated. Regarding the question especially as it respects
the Granite rocks as an unsettled one, the hypothesis is accepted so far as it
supports the view, that the Granitic masses have forced themselves through
the deposited beds in a state of, probably, igneous fusion, and have thus
produced disturbances of several kinds. For example, the consolidated
beds have been rended by the force applied, and fissures of varied sizes and
depths have been the result. The heated mass being kept for some time in
contact with the deposited rocks would effect these changes, which are
regarded as metamorphoses, and alter the chemical constitution of the Slates
and Sandstones.
When Greenstones, Basalts, and the like igneous masses have been thrust
through, we find that the fissures produced by the more intensely-heated
fluid masses are filled in with the matter which constitutes that which forms
the primitive dyke.
At the same time, water converted into vapour would be introduced
under pressure, and combine with the substances originally present in the
sedimentary deposits, and produce many mineral compounds different from
those existing in the detrital beds.
Professor Hausmann states that the Clay-Slate which was used in con-
structing a blast furnace at Mägdesprung, in the Anhalt territory, had,
from the long operation of heat without becoming fluid, acquired an aspect
like silicious Slate-in appearance very much resembling the rock which is
found in the vicinity of Greenstone, where that rock is in contact with
Clay-Slate. The same author notices the crystallization of oxide of zinc in
CHAP. I.]
ALTERATIONS PRODUCED IN ROCKS.
221
iron furnaces, sometimes accompanied by salts of potassium and sulphides of
lead in the walls of smelting furnaces.*
De la Beche writes: "It would be uselessly occupying time to attempt a
description of all the altered rocks which occur in Cornwall, inasmuch as
the varieties are as considerable as the composition of the rocks brought
together under the necessary conditions. The Slates not unfrequently become
hard and of a dark colour; dark purple is by no means an uncommon tint.
Another common variety consists of a glossy grey Slate, often containing
disseminated and imperfect crystals of a mineral resembling chiastolite.
"The coast from St. Ives to Penzance affords a good opportunity of
studying the alteration of fine-grained Greenstones and ordinary grauwacke
Slates, portions of these rocks occurring on the outskirts of the Land's End
Granite in a manner to render the junction of the two classes of rocks very
accessible."+
Dr. Forbes has carefully studied the mineralogical character of rocks
forming the mining district from St. Ives to the Land's End. Veins of
actinolite, he points out, are very common among the Greenstones of this coast,
and veins of schorl are also found among the same rocks at St. Ives. Schorl is
a mineral which may be decomposed in one place and, under favourable
conditions, recomposed in another. We have evidence in the schorl rocks
of Trevalgan, near St. Ives, and at Rosemerrin, near Morvah. Schorl may be
observed between, and approaching the joints of the Granite, in many places,
as at Castle Trereen (the Logan Rock) and Peden-maen-anmear. Radiated
nests of schorl in the Granite are common in many places where that
mineral is abundant, especially in the rocks in the vicinity of Wicca Cove,
near Zennor. Schorlaceous Slates are also found in Castle-an-Dinas and
other places. De la Beche says: "We may suppose the schorl to have been
introduced amongst the ordinary grauwacke Slates, of which they constitute
a continuous part subsequently to the intrusion of the adjoining schorlaceous
Granites. The mica also in many cases appears to have been formed in the
altered rock from matter received from the adjoining Granite, more par-
ticularly when the Granite is very micaceous; and felspar in the gneiss-like
variety may have been often added in the same manner. That these minerals
may have been introduced is rendered far from improbable from the artificial
formation of minerals resembling mica and felspar."
The condensation of vapours and the formation of mineral substances
under their influence have been already referred to. These phenomena
should be examined in connection with the changes which are observable in
rocks, which are traceable to heat derived from the intrusion of rocks of
high temperature. It is not unusual to find native copper in the minute
cracks formed in the Greenstone rocks themselves. Examples, as we have
already stated, may be observed at Penolva, St. Ives, where the occurrence
of those strings of metallic copper led to the sinking of a shaft. At several
places in the Hornblendic and Serpentine rocks of the Lizard, and in many
of the Greenstone masses, for example, native copper has been observed in the
* Hausmann, "On Metallurgical Phenomena as illustrative of Geology." (Jameson's "Edinburgh New
Philosophical Journal," January, 1838.)
† De la Beche, "Geology of Devon and Cornwall."
“Transactions of the Geological Society of Cornwall,” vol. ii. p. 260.
222
[BOOK II,
THE FORMATION OF DEPOSITS.
Greenstone quarries worked near Flushing, on the banks of Falmouth Har-
bour, and in the neighbourhood of Penryn, extending towards Pons-an-Nooth
Valley, where some curious mineralogical phenomena may be observed.
The bearing of this may not be evident at first to the superficial observer,
but the influence of dissimilar rocks on the conditions of the mineral veins
is, to a considerable extent, explained by the phenomena under consideration.
By the influence of atmospheric changes, by the action of water, asso-
ciated by the powerful effects of heated masses, rocks have been finely
comminuted and transported from the parent rock. These have been
formed into clay, which has afterwards been converted into Slates by the
influence of electric currents, or mechanical pressure, during those changes.
Divisional planes have been produced and fractures formed which have
subsequently presented the conditions of mineral veins. Mechanical pres-
sure has been shown by Professor Tyndall to produce lamination; heat we have
seen will do so, and electric currents will give rise to a similar structure.
That the process of lamination might be commenced in moist clay
by the action of electricity was first shown by Mr. R. W. Fox.* He con-
siders-from his well-conducted experiments-that the general laminative
condition of the clay appeared to indicate that a series of voltaic poles were
produced throughout the clay, the symmetrical arrangement of which had a
corresponding effect on the structure of the clay, and that this view was
confirmed by the occurrence in several instances of veins, or rather laminæ,
of oxide of iron or oxide of copper, according to the manner in which those
experiments were conducted. Mr. Fox points out the bearing of his
experiments upon the cleavage or lamination planes of rocks, and "con-
siders the prevailing directions of electrical forces, depending often on
local causes, to have determined that of cleavage, and the more or less
heterogeneous nature of the rock to have modified the extent of their
influence."
The problem relating to the influence of weak electric currents in deter-
mining the lamination of clay was determined by the author in 1848.
Adopting the method of experiment adopted by Mr. Fox, I fitted up
a square vessel with a zinc plate, and one of copper, each 14 inches long
by 8 inches wide, against two of its sides; these were connected by an
arch of thick copper about 18 inches long. When this vessel was filled
with water a voltaic circuit was completed, and from the chemical actions
induced, a weak electrical excitement ensued.
This arrangement may be imagined to represent a natural basin, in
which certain electrical conditions prevail. A mass, weighing 10 lbs., of
Stourbridge clay was placed on an inclined plane, and by water dropping
from a cistern, supplied with water from the well in Trafalgar Square, it was
very slowly carried into the trough in a state of fine division, and gradually
deposited in the water according to the law of gravitation, and under the
influence of such forces as may be excited during the period of subsidence,
it being, in this experiment, the force of voltaic electricity. It required ten
months to wash down the mass of clay and to deposit it between the plates.
The deposition being complete, the flow of water was stopped and the fluid
* See "Reports of the Royal Cornwall Polytechnic Society" for 1836-37, &c.

CHAP. I.]
THE LAMINATION OF CLAY.
223
allowed to evaporate at the atmospheric temperature. This occupied four
months more. Another period of three months was spent in drying the clay so
as to admit of its removal in a solid mass. Thus the experiment was alto-
gether continued over a period of seventeen months. When carefully broken
the section exhibited several remarkable peculiarities. The first feature to be
noticed is one which has been observed to a greater or less extent in every
experiment made, and the experiments, under various conditions, have been
several times repeated. The woodcut, Fig. 26, will assist the description.
3
The water carrying the clay flowed in on the zinc side z, consequently
there was a natural tendency to
heap up on that side rather than
on the copper side C. There was
always shown a tendency to form
curved lines, opposed to the in-
fluence of gravity, as the particles
approached the copper plate;
these curved beds are indicated
by the italic letters a, d, f.
C
a
Had this been observed in a
one instance only it would not
have deserved attention; but
when we find the same thing
occurring in perfectly still water,
and always on the side next the
copper plate, it becomes instruc-
tive, clearly proving the tendency
of minute particles of matter to
Fig. 26.-Lamination of Clay by Electricity.
arrange themselves in obedience to the directions of electric currents.
Z
2
f
d
a
The lines of bedding were always more or less curved lines, the altera-
tions in the thickness of the beds being occasioned by irregularities in the
flow of the water, and on several occasions an actual cessation of the flow.
As shown in the woodcut at 1, 2, 3, numerous fine lines were seen running
across the beds. These lines were marked most distinctly on the mass when
first broken, and formed cleavage planes cutting through the stratified
beds-thus imitating, on a small scale, many of the phenomena of lamination
and cleavage as exhibited by rocks in nature.
Dr. Berger, in 1811, observed that the grauwacke of the cliffs of White-
sand Bay, near Millbrook, Cornwall, separated into "very regular rhom-
boidal joints."* Professor Sedgwick observed of Devon and Cornwall:
"Whenever any natural section of the country exposes an extended surface
of the Granite, we find portions of it divided by fissures, which often for a
considerable extent preserve an exact parallelism among themselves." And
again: "These masses are not unfrequently subdivided by a second system
of fissures nearly perpendicular to the former, in consequence of which
structures the whole aggregate becomes separated into blocks of rhomboidal
form." †
The late Mr. J. S. Enys, of Enys, observed, in 1833, that the vertical divi-
* "Geological Transactions," vol. i. +"Cambridge Philosophical Transactions," vol. i.
224
[BOOK II.
THE FORMATION OF DEPOSITS.
sional planes or joints of the Granite near Penryn took a general direction
from N.N.W. to S.S.E., varying but a few degrees from those points. Sir
Henry de la Beche wrote, in 1834: "The cleavage of the Devon and Cornwall
Granite is frequently in given directions over considerable areas, showing
that the causes producing it have acted on the large scale. . . . . The Granite
on the northern part of Dartmoor was not only cleaved perpendicularly in
the direction N.N.W. to S.S.E., but also in lines at right angles, or nearly
so, to it.”*
No man ever observed the geological structure of a country with the
close exactness of De la Beche. The advance of practical geology to its
true position as a science is mainly due to him. Commencing, at his own
cost, the Geological Survey of Cornwall, which, with its mines and mineral
formations, presented numerous most complicated phenomena, he, single-
handed, with vast industry did the work of many men, and in his book on
Devon and Cornwall he has left an imperishable memorial. From this work
originated the Geological Survey of the United Kingdom-which has been
carried on with surprising exactness—and the Museum of Practical Geology,
which preserves examples of all the rocks and minerals of our country, and
enables every one to become acquainted with the important "sermons in
stones." In addition to these, the Mining Record Office, over which the
author has presided for thirty-eight years, was organised mainly through
the same influence.
The informations given by De la Beche are so much to the purpose that
we give his own words. Speaking of cleavage and the like he says
"Though the general direction of these lines,† which may be termed great
divisional planes, to distinguish them from the cleavage lamination to be
presently noticed, may be N.N.W. and S.S.E., varying only a few degrees
from those points, these planes are by no means confined to it; on the con-
trary, there are many exceptions to it in the Granite districts of Cornwall and
Devon. To show an average amount of local variation in this respect, we
will select the coast between Peden-maen-du and Peden-maen-anmear,
which includes the Land's End, as it is easily visited and the great divisional
planes well seen. Commencing with the north, they run as follows:-
"At Peden-maen-du
Near Carn Clog
Near Carn Creis
Nanjisal, or Mill Bay
Carn Barra
Carn Mellyn
•
Tol-Peden-Penwith.
On west of Porth Chapel.
Peden-maen-anmear
•
•
·
•
3250
325° and 242°
318°
316°
318°
•
328°
316° and 218"
328° and 225°
320°
"Taking the present magnetic north to be about 335° at the Land's End,
the leading great cleavage of Peden-maen-du and Carn Clog would differ
from it 10°; that of Carn Creis and Carn Barra, 179; that of Mill Bay and
Tol-Peden-Penwith, 19°; that of Carn Mellyn and Porth Chapel, 7°; and
that of Peden-maen-anmear, 15°; the average of the whole differing from it
between 13° and 14°. It will be observed that the cross great cleavage is not
always sufficiently well characterised to be noticed, and that it varies more
* "Researches in Theoretical Geology." † De la Beche, “Geology of Cornwall,” pp. 271-73.
CHAP. I.]
DIVISIONAL PLANES IN ROCKS.
225
considerably than the north and south cleavage, the cross cleavage planes at
Carn Clog and Tol-Peden-Penwith differing 24º in direction. The line of cross
cleavage makes an angle of 83° with the main cleavage at Carn Clog, of 98° at
Tol-Peden-Penwith, and of 103° near Porth Chapel, the angle being measured
on the west. The above will convey a fair idea of the general variations in
the directions of the great divisional planes of the Granite in Cornwall and
Devon, the results of many hundred observations on which would give 80 per
cent. of instances in which the great divisional planes differed only 14° from
the present magnetic meridian in the district, and about 15 per cent. of cases
in which they differed between 14° and 20°, leaving about 5 per cent. of
instances in which the north and south lines approximate the cross planes.
The same numbers may be nearly taken to represent the proportion of cases
in which the latter approximate to within a few degrees of a right angle to
the other main planes.
"While a large proportion of the great divisional planes in the Serpentine
of the Lizard have a direction approaching the present magnetic meridian,
we find several exceptions to it. The following will serve to show the
prevailing direction in the Serpentine of different parts of that district :—
Henscarth Rock (Mullion)
Mullion Cove (south side)
Between Vellan Head and Gue Graze
Rill Head
On north of Kynance Cove
Lankidden Cove
Black Head
Porthbeer Cove
•
Goonhilly Downs (north of Trelowarren).
·
•
335° and 225°
•
355°
•
335° and 230°
•
340°
290° and 211°
287° and 197°
295°
312° and 198°
335°
"It will be observed that while the prevailing direction, with the exception
of the local variations at Rill Head and on the south side of Mullion, is in,
or within a few degrees of, the magnetic meridian from Kynance Cove to
Goonhilly Downs; the main divisional planes between Kennack and Coverack
Coves differ between 239 to 48% from it. While on the subject of the
Lizard, it may be observed that the great divisional planes which traverse
the hornblende Slate in it do not appear to have any strongly-marked and
prevailing direction throughout. Near the lighthouses they hold a course
of 263º, and somewhat farther west, towards Penolver Point, one of 322°.
Perhaps, as a whole, the divisional planes of the hornblende Slate are more
frequently within a few degrees of true east and west than in other directions.
At Porthalla they have a direction of about 268°.”
It appears necessary, to enable the student to follow the reasoning of the
several hypotheses given of the conditions under which the mineral lodes.
have been filled with metallic ores, that the chemical constitutions of the
rocks enclosing the veins should be known.
Many analyses have been made from time to time by chemists, who have
established their names for reliability in investigations of this nature, which
agree in the main.
Many philosophers, especially such as have a leaning towards chemical
phenomena, have supported the hypothesis that the metallic minerals have
been derived from the rocks in which the lodes are enclosed. They suppose
that water percolating slowly through the rocks carried into the fissures in
Q
226
[BOOK II.
THE FORMATION OF DEPOSITS.
solution the metals found. This, of course, involves the necessity of the
existence of the metals, in a diffused state, in the rocks. This iš not impro-
bable. It must be borne in mind, however, that hitherto the chemical
analyses have not afforded the evidence necessary to support this view. It
should be remembered that none of the analyses have been made with a
view to the detection of minute quantities of metallic matter; to do this they
should have been made on a much larger scale than they have been.
The analyses of Killas, Granite, Elvan, and Greenstone which are given,
were all made by Mr. J. A. Phillips, and were published by that gentle-
man in his paper on "The Rocks of the Mining Districts of Cornwall and
their Relations to Metalliferous Deposits," read before the Geological Society
of London.* These have been chosen as being the most recent, and therefore
they have the advantages of all the improvements which have been introduced
into modern chemistry. The examples analysed have all been selected
by Mr. Phillips himself, with the especial purpose of learning if the rock
conditions afforded evidences of the processes involved in its formation.
Especially are these more valuable than any others, since for many
years Mr. Phillips has devoted his powers of observation to the pheno-
mena of mineral deposits in all parts of the world, and under very varied
conditions. It must not be forgotten these analyses were made with a
view to determine the lithological character of the rocks, and not to ascer-
tain their mineral constituents. The German chemists appear to have found
minute quantities of the metals in most of the rocks examined.
KILLAS-CLAY-SLATE.
TABLE SHOWING THE CHEMICAL COMPOSITION OF SEVEN VARIETIES OF CORNISH Rocks.
I.
II.
III.
IV.
V.
VI.
VII.
Water
Silica.
{hygrometric
Phosphoric anhydride.
I'00
3.09
2.00
*35
*48
*39
4.12
•94
I.26
•
60.42 50.92
5.81
•67
2.74
6.97
2.18
53°30
67.32
40.22
32.98 67.82
trace
·66
trace
•
Titanic
•2I
trace
trace
•13
•15
trace
Alumina
20.84
20.79
21.73
20.85
24'ΟΙ
16.73
9.56
Ferrous oxide
1.89
4'92
4.28
1.66
II.27
13.71
5'02
Ferric
8.17
13.41
6.01
2.83
4.21
7.03
trace
Ferric persulphide
S. trace S. trace
-68
Manganous oxide
*39
trace
I.20
Lime
1.71
1.62
trace
2.03
4'II
4.90
2.58
Magnesia
trace
*75
Potassa
•77
Soda
•
1.55
*93
4.08
2.92
4.20
trace 6.52
⚫60 1.67
3.37 3.57
II.52
3°42
.72
2.37
•63
4.32
100'04
99'93 99.35
99'94 99'52 99.31
100'09
Specific gravity
2.60
2.73
2.52
2.71
2.95
2.82
2.73
Nos. I. and II. are examples of Killas from Polgooth mine, near St. Austell; the first specimen of
rock being taken from above the adit, the second from the 100-fathom level.
No. III. is Killas from "Sanctuaries," St. Austell.
No. IV. from the 215-fathom level at Dolcoath.
No. V. is from Botallack, St. Just. Surface near the lode.
No. VI. is from the 130-fathom level, Botallack.
No. VII. from Wheal Seton, Camborne; taken from the 160-fathom level.
Quarterly Journal of the Geological Society" for August, 1873.
+ It is interesting to know that Mr. J. A. Phillips has been for some time engaged on a work on
"Ore Deposits"-a subject which his large experience enables him to treat more thoroughly than almost
any other man.
CHAP. I.]
CHEMICAL COMPOSITION OF ROCKS.
GRANITE.
TABLE SHOWING THE COMPOSITION OF THREE VARIETIES OF CORNISH GRANITE.
I.
II.
III.
Water {combined
( hygrometric
*34
.87
*33
•89
trace
•89
Silica
74.69
74.54
70.65
Alumina
16.21
14.86
16.16
Ferrous oxide
1.16
•23
*52
Ferric
trace
2.53
1.53
Manganous oxide
•58
trace
trace
Lime
•28
29
*55
Magnesia
*48
trace
trace
Potassa
3.64
3.73
8.66
Soda
1.18
3.49
*54
Lithia
•IO
trace
99*55
100.54
99.83
Specific gravity
2.64
2.66
2.62
No. I. from Carn Brae Hill, Redruth.
No. II. from Botallack mine.
No. III. from Chywoon, Morvah.
ELVAN.
TABLE SHOWING THE COMPOSITION OF FOUR VARIETIES OF CORNISH ELVAN.
I.
II.
III.
IV.
Water
Shygrometric
combined
'II
•26
*43
*34
*49
2.03
I.27
6.11
Silica.
72.51
72.82
71.46
47.35
Alumina
13.31
15.12
15.38
20.60
Ferrous oxide
3.87
trace
2.27
1.60
Ferric
Manganous oxide
Lime
Magnesia oxide
Potassa
Soda
trace
""
I.75
*30
3.10
•62
trace
trace
trace
⚫60
•
*52
*47
4.72
1.52
1.06
*22
6.12
6.65
6.25
5:51
6.29
0.43
*51
2.79
3'58
Fluorine
trace
trace
100.II
100.32
100'10
99.81
Specific gravity
2.62
2.64
2.65
2.70
227
No. I. Coarse-grained and highly porphyritic.
No. II. Much less coarse in grain.
No. III. As compact as chert, and with a conchoidal fracture.
No. IV. Contains an unusual amount of brown mica, and in other respects differs materially from
ordinary Elvan.
GREENSTONES.
FROM NEAR THE VILLAGE OF TRELILL, ST. KEW.
Mean.
Proportion of carbonate to rock-carbonates
rock
25.73
74:27
100'00
The carbonates are composed of carbonate of calcium
96.20
99
magnesium.
3.80
100.00
Q 2
228
[BOOK II.
THE FORMATION OF DEPOSITS.
The percentage composition-deduction being made of the carbonates-is as follows:
I.
Water { hygrometric
'92
II.
*93
combined.
4.38
4:58
Silica
48.66
Phosphoric anhydride
48.37
trace
trace
Alumina
Ferrous oxide
23.27
22.92
13.12
13.03
Ferric
>>
*77
ΙΟΙ
Manganous oxide
trace
•
Magnesia
3.20
trace
3.18
Potassa
*57
•63
Soda
5.17
5.22
100.06
99.87
FROM BOTALLACK (I.) AND LEVANT MINE (II.).
Water {hygrometric
combined.
I.
II.
•21
*20
•24
•22
Silica
Alumina
47.90
48.10
19.26
19.37
Ferrous oxide
Ferric
·
Manganous oxide
Lime
Magnesia
Potassa
Soda
•
7.55
7.79
•
1.67
I'42
trace
trace
10.57
10.51
7.97
7.56
*49
*42
4.33
4.07
100*19
99.66
In "Researches in Physical Geography," published in the "Transac-
tions of the Cambridge Philosophical Society" by Mr. Hopkins, we find
some speculations upon the action of the forces, to which the uplifting of
large masses of the Earth's crust is due; and as these remarks bear on the
lines of fracture-the fissures or rents, which became eventually mineral
veins-they demand attention. The author says, with respect to the action
of an elevating force: "I assume this force to act under portions of the
Earth's crust of considerable extent, at any assignable depth, either with
uniform intensity at every point, or in some cases, with a somewhat greater
intensity at particular points; as, for instance, at points along the line of
maximum elevation of an elevated range, or at other points where the actual
phenomena seem to indicate a more than ordinary energy of this subterranean
action. I suppose this elevatory force, whatever may be its origin, to act
upon the lower surface of the uplifted mass through the medium of some
fluid which may be conceived to be an elastic vapour, or in other cases a
mass of matter in a state of fusion from heat.
“The first effect of our elevatory force will, of course, be to raise the mass
under which it acts, and to place it in a state of extension, and consequently
of tension. The increased intensity of the elevatory force might be so rapid
as to give it the character of an impulsive force, in which case it would be
impossible to calculate the dislocating effects of it." He further supposes
"this intensity and that of the consequent tensions to increase continuously,
till the tension becomes sufficient to rupture the mass, thus producing
fissures and dislocations." Treating of the nature and position of such dis-
locations, he says: "These will depend partly on the elevatory force, and
partly on the resistance opposed to its action by the cohesive power of the
Our hypotheses respecting the constitution of the elevated mass are
mass.
CHAP. I.]
THE GRANITES OF DARTMOOR.
229
by no means restricted to that of perfect homogeneity; on the contrary, it
will be seen that its cohesive power may vary in general, according to any
continuous law, and, moreover, that this power, in descending along any
vertical line, may vary according to any discontinuous law, so that the truth
of our general results will be independent, for example, of any want of
cohesion between contiguous horizontal beds of a stratified portion of the
mass. Vertical, or nearly vertical planes, however, along which the cohesion
is much less than in the mass immediately on either side of them, may pro-
duce considerable modifications in the phenomena resulting from the action
of the elevatory force. The existence of joints, for instance, or planes of
cleavage, in the elevated mass, supposing the regularly jointed or slaty
structure to prevail in it previous to its elevation, might affect in a most
important degree the character of the phenomena." This author considers it
impossible that a succession of parallel fissures could be formed in thin
lamina subjected to such tension. "In any system of parallel fissures," he
continues, "which are not remote from each other, the fissures could not
have been formed in succession," though in an assumed case "of two systems.
of tension perpendicular to each other any number of parallel fissures may be
formed simultaneously. It is evident that in whatever manner a system of
parallel fissures may be produced after their formation, the only tension of the
mass between them must be in a direction parallel to them. Consequently,
should any other system be subsequently formed, it must necessarily be in a
direction perpendicular to that of the first system. No two systems of parallel
fissures not perpendicular to each other could be formed by causes similar to
those of which we have been investigating the effects." And finally he states
that "if the elevated mass be of great superficial extent, partial irregularities
in its boundary will have no appreciable effect in the direction of the fissures;
and though two remote fissures of the same system might, in such case, be
inclined at any angle to each other, any two adjoining fissures would in
general be approximately parallel."
DEVONSHIRE.—The fine Granitic mass of Dartmoor is considered by De la
Beche "to have been protruded after, at least, the deposit of the upper part
of the grauwacke series." He refers especially to the bent and contorted
conditions of the carboniferous and other Slates around Dartmoor as showing
the influence of the Granitic intrusion. There is, however, not any specific
difference to be found between the Granite of Dartmoor and the Granitic
masses of Cornwall. They are in both counties interpenetrated by Granitic
veins and Elvan courses, and we have on the western side-at Peter Tavy-
large masses of Greenstone, which may be traced on to Branstone and
Dunderton, crossing the river Tamar at Greston Bridge. Long lines of
Greenstone are also found skirting the Granite on its north-western edge
from Great Cranaford to, and beyond, Okehampton. The southern half of
Dartmoor is bounded by the Devonian rocks and the Killas or Clay-Slate of
Cornwall, the northern boundary belonging to the Carboniferous series of
Devon.
On the northern boundary of Dartmoor, we find the copper mines of
Belstone and Furzdon (now Wheal Emily) in the Clay-Slate rocks, and
a few mining explorations have been made farther south, at and near Bride-
230
[BOOK II.
THE FORMATION OF DEPOSITS.
stow. As we advance from Lidford onwards to Mary Tavy and to Tavistock,
we find some important mines of tin, copper, and lead which is argentiferous,
with many curious deposits of manganese between this point of Dartmoor
and Launceston, and towards Tavistock, at Brent-Tor.
On the south, especially in the neighbourhood of Ashburton and Buck-
fastleigh, we find mines of tin and copper in the Clay-Slate; and passing
westward by Brent and Ivy Bridge to Plympton, we have the well-known
mine of Old Bottle Hill and several others.
The deposits of argentiferous lead ore in the Devonian rocks near
Combe Martin are remarkable in many respects, and will duly receive atten-
tion. In the Devonian and the carboniferous rocks of North Devon peculiar
Limestone veins occur. At a short distance from Bampton the author examined
a lode of this description, which had suddenly changed to a vein of Bournonite
(a sulphide of lead and antimony). This ore gave upon analysis—
Antimony.
Lead.
Copper
Iron.
Sulphur
·
28
38
14
I
19
100
and contained twenty-five ounces of silver to the ton of ore.
SOMERSETSHIRE.—The general form of the western portion of Mendip
range may be thus described. Its highest part-which is, according to the Ord-
nance Survey, 999 feet above the level of the sea-includes Black Down. It
presents a smooth uninterrupted surface for a considerable way down either
declivity on the north and south; ravines then begin to appear, which in
descending are enlarged into defiles or combs. On the southern side in
particular the range is intersected by the deep defile of the Cheddar cliffs,
which, in ascending to the north, ramifies into those sinuous dells and ravines
that mark the southern face of the Mendips. On the northern side appear
the two deep combs of Burrington and Dolborough; both enter the Mendips
nearly at right angles with the vale of the Yeo.
The nucleus of the Mendip strata consists of the Old Red Sandstone,
which occupies the highest part of the range in Black Down. In the more
central part of Mendip the Old Red Sandstone is again seen in Nine Barrow
Down, and about three miles to the north of Wells, extending in the direction
of Chewton Mendip.
The Limestone on the north and south of this elevated part of Mendip
forms a continuous body, which sweeps round the eastern extremity of the
high Sandstone ridge. On the southern side of the highest part of Mendip
the Limestone generally dips 20° at first to the south, 35° west, and subse-
quently to the south 20° west as far as Cheddar, a distance of three miles;
but in the western direction, extending towards Crook's Peak, and the
southern side of Blendon Hill, the dip is to the south 30° to 38°, west at an
angle of 30° to 36°. The Sandstone strata on the northern side dip at
angles gradually increasing from 7° to 300 or 40°.*
* Consult, for a more extended and detailed account of the geology of Mendip, Mr. Weaver's "Geolo-
gical Observations of Part of Gloucestershire and Somersetshire" ("Geological Transactions," vol. i.
Second Series).
CHAP. I.]
COPPER ORE IN SOMERSETSHIRE.
231
Some years since (1816) a shaft was sunk at Stanton, above the village of
Alcombe, in consequence of some indications of copper in the rock there,
but the quantity of ore found was so small that the workings were soon given
up. Mr. Horner found amongst the rubbish some pieces of green carbonate
of copper with grey copper ore. Similar trials, with no better success, were
made at Perry, near the northern extremity of the Quantock Hills. Mr. Horner
found there, among the rubbish, specimens of malachite and of brownish-black
sulphide of copper.
Nests of copper are occasionally found in the Limestone at Great Holwill,
where Mr. Horner observed the green carbonate of copper enveloped by
brown ochreous earth. At Doddington a large quantity was found some
years ago. A loose friable quartzose Sandstone appeared to contain so much
copper ore that a mine was sunk in it. In order to drain the works—which
were situated upon the rise of the hill-a shaft was sunk for the purpose of
driving a level, from north to south, up to the workings, expecting at the
same time to cut across the veins of metal which might exist there, as they
are generally supposed in this part of the country to run east and west.
They had proceeded a very short way in driving this level when they came
upon a black slaty Limestone, and immediately afterwards they found a nest
of copper ore, consisting of green carbonate and yellow sulphide of copper.
This mine was abandoned after a short trial, as the produce was not sufficient
to bear the expense of an engine to drain off the water.*
*
In the preceding pages will be found some statements relative to the pro-
duction of lead ore, zinc-blende, and iron ore on the Mendip Hills. These
deposits are nearly always confined to the Limestone districts. In the
Brendon Hills, chalybite, or spathose iron ore, has been for some years
extensively worked. This form of iron ore-always associated near the
surface with limonite (brown hematite)-extends over the Eisen Hill, and
on to Exmoor. In this last district, extensive lodes are known; but
except in ancient times but very few of them have been worked. At
Winford, and extending towards Bristol, many hematite deposits have been
found.
Sir Charles Lyell † remarks that "near Bristol, in Somersetshire, and in
other counties bordering the Severn, the unconformable beds of the Lower
New Red resting immediately upon the coal, consists of a conglomerate called
'Dolomitic,' because the pebbles of the older rocks are cemented together
by a red or yellow base of Dolomite or Magnesian Limestone. This conglo-
merate, or breccia-for the imbedded fragments are sometimes angular—
occurs in patches over the whole of the downs near Bristol, filling up the hollows
and irregularities in the Mountain Limestone, and being principally composed,
at every spot, of the débris of those rocks on which it immediately rests. At
one point we find pieces of coal shale, in another of Mountain Limestone
recognisable by its peculiar shells and zoophytes."
The metalliferous portions of this district are traversed by mineral veins
in all directions, sometimes in such numbers as to constitute a kind of net-
* "Sketch of the Geology of the South-western Part of Somersetshire" By Leonard Horner, F.R.S.
("Transactions of the Geological Society,” vol. iii. 1816.)
"Manual of Geology," p. 305. Fourth edition.
232
[BOOK II.
THE FORMATION OF DEPOSITS.
work on a large scale. The veins observe no regular order in their dip, but
are sometimes vertical, and often inclined one way or the other indiffer-
ently. Neither has it been observed that the metalliferous value of a lode
in the Mendip Hills has any relation to either dip or direction. The lodes
vary in width from one to six inches, 'but are sometimes enlarged, espe-
cially at points of intersection to the breadth of one, two, or even, in rare
occasions, to three feet.
Few workings have gone down in the conglomerate to a depth of more
than twenty or thirty fathoms. In all probability the veins do not pene-
trate into the subjacent Carboniferous Limestone or into the Old Red
Sandstone.
Mining-but on a limited scale-has been carried on in the New Red Sand-
stone, and the Clay Marl formations, on the eastern borders of the Broadfield
Down range. The district near Winford consists of the Carboniferous Lime-
stone, which is succeeded by the New Red Sandstone, declining towards the
vale. In this is found a clay ironstone-called in the district Reddle-which
varies in thickness from five to six feet. To this bed pits placed at convenient
distances are sunk, about eighteen yards in depth, and connected with each
other by underground ways. The reddle thus obtained is used as a pigment.
There are four or five small works at Winford, from which Brown Hematite
is raised.
GLOUCESTERSHIRE.-The Limestone formations which surround the Coal
Measures of the Forest of Dean have been from a very early period worked
for iron ore, and considerable quantities of Brown Hematite are still obtained
from this region. It should here be noted that this iron ore occurs rather as
deposits—in the water-worn cavities of the Limestone-than in such fissures
as are usually grouped under the term of "lodes" or "veins." Around Bristol
from time to time lead ore has been discovered in the Limestones, but it has
rarely proved to be of any importance. The geological formations north of
Gloucester are rarely metalliferous. As we avoid the Coal Measures-
which occupy largely the centre of England-there are no rocks of any
mineral value which demand especial notice.
DERBYSHIRE AND ADJOINING COUNTIES.-The Romans worked the lead
mines of this district, and probably the superficial deposits were searched by
the earlier native inhabitants of this then wild region. The geology of
Derbyshire corresponds very nearly with that of the northern counties.
Farey* states that the lower part of Derbyshire is formed of 870 feet of
Limestone, with three beds of igneous rock interspersed, whose aggregate
thickness is 240 feet. Professor J. Phillips observes that these are sur-
mounted by shale, with their alternations of Sandstone, Limestone, Iron-
stone, &c., to the extent of 500 feet, and the hills are crowned by bold
ranges of Millstone Grit and its accompanying Sandstones, 360 feet in
thickness."†
The uppermost regular strata in Derbyshire below the gravels is the
Red Marl, which is bounded on the north by the great Derbyshire Fault,
commencing near Colwick, in Nottinghamshire, and extending across the
county, terminating in the coal-field of Newcastle-under-Lyne.
*Farey's "Derbyshire."
+ Phillips's "Manual of Geology."
CHAP. I.]
THE GRAVEL DEPOSITS OF DERBYSHIRE.
233
CHERT, a silicious substance much used by the potters, is found in the
Limestone in large detached masses, and also in thin strata.
GYPSUM, or ALABASTER, is a product of this district, forming
thin beds in particular spots, and sometimes it is found accumulated in nodules
of irregular and confused crystals. Chellaston Hill in particular would present
a water-worn rock of gypsum were it not for the clay which covers it.
In
Nottingham and Staffordshire several gypsum beds appear.
This important mineral county, and the adjoining counties of Not-
tinghamshire, Leicestershire, and Warwickshire, have been frequently
described. A large tract of this part of mid-England is remarkable for
its Coal formation, which is beyond the province embraced by this volume;
the minerals to which attention is directed being generally confined to
the Limestone formations and to the igneous rocks, which are connected
with the Limestones gathering around the Coal-basins, but rarely intruding
upon them.
Farey devotes, in his work on Derbyshire, many pages to the considera-
tion of the large deposits of gravel which are spread in patches, or in
"hummocks" over nearly the whole of the county. He tells us, that he uses
"the word 'gravel' to express every kind of alluvia with rounded stones,"
but in many instances in alluvial mixtures the stones are angular, almost
like gun-flints in shape, as happens frequently with the white chert in
alluvia on the Limestone strata, or, they are like the larger chippings of
a stonemason's yard, and called Ratchel, Rumel, Keale, Skerry, or Rubble.
If large, such are called Boulders; if rounded by attrition, Self-stones
if possessing still the original shape and angles of the block. By the
clearing of the waste lands, the boulders and 'self-stones' have been largely
removed and broken up or converted into lime, or used in wall-fences and
buildings, except that here and there a few such blocks are to be seen on
commons or in particular fields which have not yet been cleared " (Farey was
writing in 1811); "some because they will not answer the expense of such
clearing, or Ridding, as it is more generally called."
He also gives a list of hills on the tops of which these detached stones
are still to be found, and of narrow valleys which "have their bottoms
still covered by large Self-stones." The Slither, or indestructible rubble
of Limestone, which occurs generally in thin sharp-angled chippings of
white and light grey and yellowish Limestones. These are lodged on the
steep sides of valleys, and, curiously enough, are "in general the most
barren spots that can be imagined, not a blade of grass, a weed, or
even a lichen having got possession of them, nor do they exhibit the
least signs of decomposition or mouldering. In general this indestructible
rubble lays on so steep an ascent that it slips from beneath the feet of
an animal which attempts to cross it-whence the name Slither, or sliding
gravel."
The Red Marl occupies most of the southern end of the county, and
spreads over Nottinghamshire, Leicestershire, Warwickshire, and Stafford-
shire, being bounded on the north by the Great Derbyshire Fault, which
commences at Colwick in Nottinghamshire, and extends across to Cheshire,
where this red marl produces the highly valuable beds of rock salt and brine
234
[BOOK II.
THE FORMATION OF DEPOSITS.
springs, with gypsum, which also occurs and is worked largely in
Nottinghamshire.
The Sienites-or Granites of Playfair-are not materially connected with
the metalliferous conditions of this large district of Central England. These
are more especially developed at Mount Sorrel, in Leicestershire, at Bardon
Hill, and the Grooby Quarry, near Ashby-de-la-Zouch.
SLATE.-The Slate rocks, although of great economic value, have no
direct relation with the mineral deposits of this district.
MILLSTONE GRIT is the most important stratum of Derbyshire. By
its thickness, its hardness, and indestructible properties it gives rise to
the most striking scenery of the county. In several places this rock is
120 yards thick. It is composed of a coarse-grained white, yellow, or
reddish freestone, easily worked, and of vast durability.
The Peak Millstones, which are known all over England, were for a long
period manufactured at Belper and to the north of that place. They are now
manufactured in Derbyshire, Yorkshire, and Cheshire.
Some of the series, which are remarkable by having spherical stones
of a light red colour, form the best Fire-stones known, and are much
used for lining the hearths of iron blast furnaces and other smelting
works where intense heat is required. The upper beds are used for paving-
stones and flags, and they split so thin that they are employed for covering
buildings.
This rock is found scattered over a wide area in Derbyshire and extend-
ing into the other adjoining counties. The gaps, however, show very
plainly that it has been subjected to an immense central denudation. This
is, however, of great benefit, as it has laid bare the great mineral Limestone .
tract of Derbyshire and Staffordshire.
THE GREAT or LIMESTONE SHALE.-This has been proved by
the shafts in the lead mines to have a thickness of from 150 to 170 yards.
This contains the Shale Limestone, said to be the bituminous marl Slate of
Werner, which produces the well-known polishing powder, Rotten-stone.
Ironstone is found in considerable beds in this Shale.
MOUNTAIN LIMESTONE.-The Geological Survey has given a
section of this formation between Monsal Dale and Buxton :-
1. Thinly-bedded Limestone, somewhat earthy, with layers and nodules of chert, and
thin shale partings in the lower beds
2. Thickly-bedded Limestone
3. Thinly-bedded Limestone and chert
•
4. Toadstone, perhaps in places as much as
5. Massive white Limestone, Miller's Dale rock, with perhaps a bed of Toadstone in
the middle, at least
Feet.
•
250
50
90
100
•
320
6. Toadstone, about .
20
•
•
500 to 600
8. Limestones, more or less concretionary, with shale partings
•
•
•
9. Limestones, some thickly and some thinly bedded: of these there is seen about
Total thickness shown without reaching the bottom
150
100
•
•
1,580
7. Very thickly-bedded white Limestone, Chee Tor rock
The cutting at the east end of the Monsal Dale tunnel, where the first bed
rises, in a series of easy rolls, from beneath the Yoredale shales and earthy
Limestones, gives the following section :—
CHAP. I.] CARBONIFEROUS LIMESTONES OF DERBYSHIRE. 235
SECTION SHOWING THE JUNCTION OF THE YOREDALE BEDS AND MOUNTAIN LIMESTONE
AT THE EAST END OF MONSAL DALE TUNNEL.
Yoredale
Rocks.
Black shale.
Earthy Limestone.
Black shale
Limestone
Black shale
•
•
•
Calcareous black shale
Black shale .
Earthy Limestone
Black shale
Limestone
Lowest Group. Black shale
Mountain
Limestone
Black shale
Limestone
Black shale
•
•
•
•
•
•
•
Earthy Limestone
Black shale
•
Earthy Limestone
Black shale .
•
Limestone.} Thinly-bedded Limestone with chert, No. 1.
Ft. in.
I 6
6
96
5
2
O
0 7
0 10
I
•
9
I I
6
•
I
O
•
8
2
6
0 3
2 5
I 9
0 9
Ο ΙΟ
I O
Ο ΙΙ
Crossing the river we find the same cherty beds as on the east of the
tunnel, and below them like thinly-bedded Limestones with shale partings.
There are two very small faults, and near one of them the rock is
curiously veined with calc-spar; a little farther on, a lode crosses the line,
its fissure is about twelve feet wide, filled in with calc-spar, among which is
scattered a little galena; the crystals are mostly in prisms ranged at right
angles to the walls, but in the middle there were some concretionary nodules.
From beneath these cherty beds rise a more thickly-bedded Limestone,
No. 2, beneath which there are again about ninety feet of Limestones and
chert, No. 3.
At the west end of Cressbrook Tunnel a thickly-bedded white Limestone,
No. 5, comes out from beneath No. 3, and runs on through Litton Tunnel, to
the west of which the beds dip down, and the cuttings are in beds belonging
to No. 3, which are here fossil bearing, and have among them thin lenticular
partings of shale and red clay.
No. 5, being carried down by the dip just mentioned below the level of
the railway, forms a range of fine cliffs along the lower part of Miller's Dale,
and may be traced along the steeply-scarped sides of the valley, while beds
belonging to No. 3 are shown in the cuttings above, till we come to Litton
Mill. Opposite this mill, however, instead of Nos. 5 and 3 being in contact,
as was the case at Cressbrook and Litton tunnels, they are parted by a thick
mass of Toadstone.
The Carboniferous Limestones of Derbyshire yield a variety of beautiful
marbles, which are used for numerous ornamental purposes. In various
parts a black marble is found in laminæ, the colour being derived from iron
and petroleum.
The Mountain Limestone stratum produces the principal mineral veins,
which contain galena (the sulphide of lead, which generally in Derbyshire
contains but little silver), the sulphide of zinc, blende or "Black Jack" of
the miners, and a native oxide of zinc. Ochres in great variety are found,
with fluor-spars of varied colours and often of great beauty, sulphate of
236
[BOOK II.
THE FORMATION OF DEPOSITS.
barytes (Cawke), and carbonate of pyrites (sulphide of iron, mundic), and at
Ecton large quantities of copper were found, and some in the adjoining
mines.
Yellow Limestone, or, as it is more frequently called, Magnesian Lime-
stone, comes next in order. In the "Memoirs of the Geological Survey of
England and Wales" this formation is thus described:-
"This is a mass of Limestone of very great but unknown thickness. Very
thin partings of shale or clay are found in it here and there, and two or more
beds of contemporaneous igneous rock, called Toadstone.
"In the upper portion the Limestones are thinly bedded and somewhat
earthy, and contain layers and nodules of chert. Below the cherty group
comes a great thickness of exceedingly massive pure Limestones, at times
semi-crystalline, of white or pale grey colour; and underneath these there is
a mixture of thickly and thinly bedded Limestones."
The Magnesian Limestones cover an immense series of Coal Measures,
which distinguishingly mark the central portion of England. With these,
the most valuable of our mineral productions, we have not at present to deal.*
The interest which attaches itself to the geology of North Derbyshire is
such, that a much larger space would have been devoted to its consideration
but for the pressure of other matters which are directly connected with the
mineral deposits, our especial subject.†
Farey remarks: "It is now supposed by many practical miners—and so
they construe their titles to the veins-that every principal vein extends
through the whole series of Limestone rocks, as from the top of the first lime
to the bottom of the fourth, but not without interruption, since the three
Toadstone rocks are very rarely broken through, I believe, so as to connect
the veins above and below them, except where faults have since happened
to follow the ranges of the veins."+
THE TOADSTONE, which seems to be a truly interbedded rock, varies
from a soft crumbly ash to a hard closely-grained Greenstone. Our imper-
fect knowledge enables us only to say that the most usual form of Toadstone
is an ashy rock. The number of the Toadstone beds is still uncertain. The
late Mr. W. Hopkins, the well-known mathematician, endeavoured with great
ingenuity to explain all the facts bearing on the matter which he could collect,
on the hypothesis of there being only one Toadstone. He does not seem to
have been aware that two, and perhaps three, beds of Toadstone have been
sunk through in the same shaft; but, besides this, he was obliged to call to
his aid faults many of which have certainly no existence. White Watson, in
his "Delineation of the Strata of Derbyshire" (1811), gives three beds of
Toadstone, and this was also Farey's view.
* The reader interested in the Coal Measures of the kingdom, and the argillaceous iron ores which they
contain, should consult "The Coal and Iron Industries of the United Kingdom," by Richard Meade.
Crosby Lockwood & Co. 1882.
+ See "The Geology of the Carboniferous Limestone, Yoredale Rocks, and Millstone Grit of North
Derbyshire," &c. By A. H. Green (Le Neve Foster) and T. R. Dakyns. ("Memoirs of the Geological
Survey." 1869.)
Werner, it is stated, understood that "the veins in Derbyshire generally descend through the
Toadstone;" and Dr. James Millar, of Edinburgh, adopted the same view. Mr. Westgarth Forster, in his
"Treatise on a Section of the Strata," curiously confounds mineral veins and faults. It is probable that
one set of faults becomes, being filled in with mineral matter, mineral veins; but many faults are never so
filled.

CHAP. I.]
TOADSTONE IN DERBYSHIRE.
237
"There seems reason to believe that in places there are three beds, but
that they are liable to thin away, as indeed is only likely; but we cannot
surely say, till the Limestone country has been more thoroughly examined,
how many Toadstones there are, and whether any or all of them spread
uniformly over the whole district; for instance, it would be very rash to
assume that the highest Toadstone of Matlock and the highest Toadstone of
the neighbourhood of Buxton belong to one and the same bed."
E.
The Toadstone of Derbyshire plays so important a part in the phenomena
of the lead lodes of the district that its conditions should be thoroughly
understood. Professor J. Phillips thus describes it: "Only one case of
interposed pyrogenous rock occurs in the Limestone tract of England to the
north of Derbyshire, but this is one of the most extensive examples known
in geology, and has given rise to several descriptions.
"The Toadstone of Derbyshire,
whether it be a single or a triple
mass, may be considered as one great
eruption of melted rock interpolated
in the Limestone series; the Whin-
sill, as it is called in Yorkshire,
Durham, and Northumberland, is
another. They do not correspond in
position among the strata; the Toad-
stone lies among lower beds than
the whin-sill. They agree in some
respects, both being to a certain
extent stratiform, irregular in thick-
ness, variously traversed by faults
and veins."
2
3
4
O
60
600 0
O
0
00
Q
0
3
Fig. 27.-Toadstone in Mill Close Mine.
Scale, 5 feet to 1 inch.-I. Limestone. 2. Black
bituminous unstratified clay. 3. Soft, crumbly,
daloidal ashy Toadstone, embedded in softer but
similar rock. a. "Leader" of Calc-spar. b. Belt
of Toadstone crushed against the fault.
It will be apparent from the
above quotation that conditions of
the Elvan courses of Cornwall, the
Toadstones of Derbyshire, and the
Whin-sills of the North of England
are in many respects similar to each
other. They are intrusive rocks-
they preserve all the special charac-
teristics of melted rocks-and thus
the influences on the strata amongst
which those igneous masses are
interposed is in each district of a
similar character. We introduce
here a striking example of the Toadstone in Mill Close mine (Fig. 27).
In small veins we often find the Toadstone entire between the veins,
forming what Farey calls a sole-stone to the vein above it and a lid-stone
to the vein below it, of the full width of the vein in each case; but from
the larger veins a crack or rent generally extends some distance into
the Toadstone, growing narrower, and often branching into small cracks,
scrins, or strings as it proceeds, and in the same manner the veins often
238
[BOOK II.
THE FORMATION OF DEPOSITS.
strike into the shale which covers the first Limestone. Those are said by
the miners to be very powerful veins which break through the Toadstone.
There is evidently a considerable amount of confusion in this view. If
attention is confined to two rocks, one much softer than the other, one very
liable, by several agencies, to be broken into fissures, while the other is
very tough, this will be apparent, and the difficulty will be removed. After
the intrusion of the Toadstone, possibly at the very period of its intrusion,
the Limestone has been cracked, all the cracks terminating at the tougher
rock, consequently, when those fissures are filled in with metalliferous
matter, this deposition ceases at the Toadstone. In some cases the fissure in
the Limestone may run close up to the Toadstone, and then when the crystal-
line force, generated in the crystallization of the sulphide of lead, takes
place in the true vein, it may produce fine cracks in the Toadstone. These
cracks admit the fluid holding galena in solution, and this by crystallising
may enlarge those cracks in the Toadstone.
The Toadstones are liable to decomposition, and then to form a tena-
cious clay, beds of which are known as wayboards. Even thick beds of this
clay divide the larger veins. May it not be that the division took place
previous to the Toadstones' decomposition or disintegration, whichever it
may be? It is stated that these wayboards often hold up and completely
divide the water of springs in different parts of the Limestone rocks.
Farey very nearly approached the truth when he wrote: "The Limestone
strata were subject to a great contraction or shrinking since their formation
and consolidation, which did not extend to the Toadstones, to the principal
wayboards, or to the shale above; yet the mechanical force with which
the sides or skirts of the veins drew apart rent or tore the Toadstones and
the shale for certain distances, where the veins abut against them. And
since the Toadstones and the wayboards effect in general a complete separa-
tion, even to water, in the different parts of the veins, besides the shale
and a vast thickness of upper measures having covered the whole, it
seems difficult to conceive any other origin to the spar and the metallic
ores which line those cracks or veins than infiltration of some sort from the
adjoining rock—a supposition which receives confirmation from the fact so
well known to miners of certain beds of Limestone in some of the rocks pro-
ducing more ore in the veins between them than is found in other beds in the
same rock; when such are called bearing measures, or feeding-ground, by
miners. The two sides of a large rider, or near or parallel veins, are seldom,
if ever, rich together." This may be true of the lead lodes of Derbyshire, but
numerous instances are known to the author, where the resemblance between
the two sides of a lode prove that they were produced under precisely similar
conditions, and consequently that the depositions are strictly similar. In
continuing his description of mineral veins, Farey gives several remarkable
instances of curious variations which are well worthy of attention. "Next
to the walls or skirts of the veins, which are of unequal distance apart in
the same vein, in many instances a lining of vein stuff, as crystals of
calcareous spar, of fluor-spar, and sulphate of barytes (Cawke), is applied;
which vein stuff in some narrow places or humps in the vein-skirts have
met, and there the vein is said to be twitched or nipt-up, and little or no ore
is there found. Upon the linings of spar or first formations of vein stuff a
CHAP. 1.]
BASALTIC ROCKS OF GREAT BRITAIN.
239
certain thickness of lead ore is deposited-generally the sulphide of lead
(galena or blue ore in cubes)—which are called either steel-grained or leaf
ore, from having a fracture something like a thorn leaf, and it often happens
that the original width of the vein and the thickness of deposited spar was
such that these crystals of ore meet, and are closely wedged together,
forming what is called one rib of ore, with spar on each side of it in the vein.
In wider veins it has happened sometimes that a second deposit of spar took
place upon the lead ore, and continued increasing until the sides met
and were close wedged, and such parts have two ribs of ore.
"In many instances, instead of regular ribs of ore being found, the deposits
of ore and of spars of different kinds seem to have gone on together, and the
ore is found dispersed in different-sized cubes, more or less perfect, through-
out great part of the vein stuff; and indeed it seldom happens that the spar is
entirely free from small cubes of lead ore even where ribs of ore are met with.”
SLICKENSIDES, or, as in Derbyshire called, "cracking-whole," are
divisions going vertically through the strata, especially the vein stuff.
The surfaces are always polished, sometimes to a state of mirror lustre.
These surfaces appear to be produced by the immense attrition produced on
two faces by rubbing them together. Sometimes the slickenside is ribbed or
slightly fluted horizontally; the sides are always in very close contact, and
the surfaces appear to be in a state of extreme tension. It sometimes
happens where one side is removed that fragments called in Derbyshire
slapits or spels fly off with loud explosions, and continue to do so for some days.
The Gang mine, near Cromford, was remarkable for this. In this mine
the miner availed himself of a curious property attending slickensides. He
drew laces, stoops, or nicks, as he called incisions, at about six inches apart
and four inches deep, with the point of his pick, from top to bottom of his
face work, which he then left for several hours; and on his return he would
find all the vein stuff furrowed, spelled, or slappited off, and laying on the sole
ready got to his hands. The Slickensides in the Eyam copper mine would,
according to Mr. Whitehurst, explode upon slightly scratching. Farey gives
the strata in which the most productive lead mines occurred in Derbyshire,
in 1811:-
In shale and shale Limestone .
In shale Limestone.
In shale and first Limestone
stone
In first Limestone
In first and second ditto.
•
4
4
56
104
ΙΟ
16
In second ditto
In second and third ditto
In third Limestone.
In third and fourth ditto
In Toadstone .
In Limestone rock
•
4
33
•
13
3
32
279
In 1881 the number of lead mines worked in Derbyshire was 240.*
WHIN-SILL.-Many memoirs have been published on the peculiarities
of the various basaltic rocks of Great Britain. Yet the question whether the
whin-sill is intrusive or contemporaneous has scarcely been satisfactorily
settled. It is often spoken of as "interstratified," and as occurring in “over-
lying masses." Mr. Trevelyan, in 1823,† published a paper on the northern
* For list, see "Mineral Statistics of the United Kingdom for 1881."
+"Memoirs of the Wernerian Society," vol. iv. p. 253.
240
[BOOK II.
THE FORMATION OF DEPOSITS.
coast of Northumberland. Professor Sedgwick* printed two papers on the
Trap rocks of Durham. He thought there was abundant evidence of intrusion,
the beds below being frequently broken and partially closed within the whin,
whilst the beds above have suffered that change which is implied by the
uncertain term of metamorphism. Mr. W. Hutton† wrote in considerable
detail of the whin-sill of Northumberland. He regarded it as strictly con-
temporaneous, and where two or three distinct beds are known in one district
he supposed that there had been successive eruptions upon the ocean floor.
Professor Phillips admits some eruptive force, but only sufficient to allow of
the whin reaching the sea bottom.‡ At a later period he stated that he had
proved the intrusive nature of this rock. The following remarks by the officers
of the Geological Survey who surveyed the country are much to the point §:
"The whin-sill is older than most of the faults of the district in which it
occurs, because these throw trap and sedimentary beds alike. We have no
clear case of the whin being unaffected by (or later than) any of the faults.
The whin is also clearly older than the mineral lodes of the district. But
what the age of faults and lodes may be we do not know. Some of the faults
are probably pre-Permian; at least the Magnesian Limestone appears to be
unaffected by certain faults which are proved in coal-workings beneath.
Others, and these generally the large east-and-west faults, are clearly post-
Permian. But we cannot generalise as to the age of the faults in this district
merely by their direction; and even if we could, the known instances of faults.
in the whin-sill are not sufficiently numerous to allow us to apply the test
with safety.
"If the Permians can be shown to have been deposited upon the denuded
edges of the trap, the proof is complete. But it is only very rarely that such
proof can be given. Generally, the evidence is of this nature:-Carboni-
ferous rocks, in which intrusive sheets of trap now occur, have been disturbed
and denuded, and their edges covered up by unconformable Permians. This,
however, is not sufficient proof; or rather it is no proof at all; for the trap
may have been intruded into the carboniferous rocks long after the deposi-
tion of the Permians. There is evidently a tendency for these sheets of trap
to keep along the lines of bedding; otherwise there would never be any
doubt as to their character. If the intruding trap began to force its way
laterally first through the carboniferous rocks, it would probably, if possible,
stay there."
Farey, in his "Derbyshire," gives "A List of Hummocks of Mineral Lime-
stones and Toadstones," which distinctly marks the situation of these two
rocks, and beyond this he gives a list of the more important mines which
have been worked for lead, zinc, manganese, copper, iron, &c.
Messrs. Green, Foster, and Dakyns, of the Geological Survey, regard the
Toadstone as an amygdaloidal rock, which they think is well shown where it
has decomposed into a soft friable clay. For by washing this, or merely
rubbing it between the hands, one may pick out the small rounded or almond-
shaped kernels of carbonate of lime which once filled the cavities in the
* "Cambridge Transactions," vol. ii. pp. 21, 129.
+ "Transactions of the Natural History Society of Northumberland," vol. ii. 1832.
Geology of Yorkshire," part ii. p. 285.
"On the Intrusive Character of the Whin-Sill of Northumberland." By W. Topley, F.G.S. and
G. A. Lebour, F.G.S. ("Quarterly Journal of the Geological Society," vol. xxxiii.)
CHAP. I.]
SECTION OF THE TOADSTONE.
241
vesicular rock. These pieces of carbonate of lime are coated with a green
mineral, and the rock thus acquires a speckled look, showing green spots on
a yellowish-brown ground. The same authorities say: "The facts that have
incidentally come under our notice respecting the condition of these forma-
tions are neither numerous nor well connected, but they tend to overthrow
the formal subdivision of the old geologists, Farey, Whitehurst, Watson,
and others." According to these observers, there are three beds of Toadstone,
spreading without break over the whole district, and dividing the Lime-
stone into four portions, called the first, second, third, and fourth Limestones.
There would be nothing strange in beds of lava or volcanic ash being
very irregular in their occurrence, and the sections show that, perhaps with
one exception, Toadstones are found at different spots on very different
horizons, and are of limited horizontal range. Beside the three regular
beds mentioned they admitted the existence of "chance" Toadstones, that
is, Toadstones of local and irregular occurrence; but it seems likely that
all the Toadstones partake more or less of this character. These authors
also speak of the several Limestones as if they each bore some distinctive
stamp, which enabled the observer to recognise them by character, indepen-
dently of relative position. With the exception of the upper cherty beds,
our experience does not tend to confirm this view. Indeed, the attempt
to identify beds far apart by mineral character alone, has been a fruitful
source of error, not only here, but also among the Gritstones and other parts
of the Carboniferous rocks; for instance, the Kinder Scout Grit of the Peak and
the Third Grit of Chatsworth were long, and very naturally, looked upon as
belonging to the same bed, because each was the lowest coarse grit in its own
neighbourhood. The fact that mistakes of much significance have been
made shows that for such details as these, nothing but careful mapping
of the whole of the country can be a safe guide, and proves the danger of
the old-fashioned method of taking a section here and a section there, and
guessing at the probable identities of the beds.
The following section of the Toadstone is given by the same authors :-
Thinly-bedded Limestones with chert; false bedding in the lower part.
[(I.) Soft, crumbly, yellow clay.
(2.) Dark olive green, mottled, coarse ashy Toadstone, amygdaloidal in parts; with large
rounded lumps, finely grained, hard and yellow, also amygdaloidal at times.
Toadstone. (3.) Toadstone, dark olive green, and more solid.
<
(4.) Ditto, shaly, with concretions.
(5.) Hard, dark grey, finely-grained Toadstone.
(6.) Toadstone, soft, concretionary, and vesicular.
Thinly-bedded Limestone full of corals
Ditto
ditto with shale bands
Massive white Limestone.
} a
a few feet thick.
"We believe," they say, "that each of the divisions of the Toadstone is a
true bed, with a gentle dip to the east; and in this case the whole will be
about 100 feet thick. All the beds were very ashy, but some had the look
of a truly melted rock. There was no sign of alteration in the underlying
Limestones at their junction with the Toadstone.
"It must be allowed that so rapid a thinning out of the Toadstone as is
required by the above explanation is somewhat startling. After a careful
examination of the ground, however, we could come to no other conclusion,
R
242
[BOOK II.
THE FORMATION OF DEPOSITS.
and as the rock seems more of an ash than a true lava, there is after all
nothing so very strange in its coming sharply to an end."*
The accompanying section of the mineral Limestone and Toadstone series
will explain their relative positions and their average thicknesses nearly,
the Toadstone strata being liable to vary in their thicknesses. The first
Limestone bassets regularly from under the great shale, all the way from
Ranter mine, near Wirksworth, to near Quarter House, north-north-west of
Great Flucton, north in an irregular line. The boundary is principally
limited by a vast fault-the Great Limestone fault. From Wirksworth south-
westward to Hopton a part of the same great fault separates the third
Limestone from the great shale, &c., south of it.
Section across a Part of the Lode at Great
N.
Depth in
Fathoms.
Hucklow.
3
S.
"Each of the three Limestone rocks," says Farey, "has its regular but
crooked range and basset edge from south to north. The first rock from
Wirksworth to North Hucklow and to Quarter House; the second lime from
the Great Limestone fault in Middleton
Wood on the north of Middleton by
Wirksworth to the same fault, again
the south side of the Windmill
Houses near Great Hucklow; and the
third Limestone from the same fault
between Wirksworth and Hopton, south,
to the same fault, against which it abuts
from a point south of Windmill Houses
to Castleton Town (Fig. 28).
60
I 65
2
70
75
к
Fig. 28.-Section of Limestone and
Toadstone.
I
2
Scale, 80 feet to 1 inch.-I. Limestone.
2. Toadstone. 3. Lode filled with "kebble,"
and "horses" of Limestone and Toadstone;
black lines, strings of galena.
on
"In like manner the three Toadstone
strata each abut against the same fault
at the south and north ends of their
respective ranges. The first Toadstone,
about one-third of a mile north-west
of Middleton by Wirksworth, and again
about three-quarters of a mile north-
north-east of Litton, near Tideswell;
the second Toadstone about a quarter
of a mile west of Cromford and again
one-third of a mile west of Windmill Houses; and the third Toadstone
from the same fault, about five-eighths of a mile west of Cromford, and
meeting it again near the entrance of Cave Dale in Castleton Town. The phe-
nomena of isolated patches of these strata detached from the range or basset
of them arise from two distinct causes, they being in one case the remaining
patches of strata which have been stripped off or denuded around them, and
in the other the superficial strata have been excavated or denuded locally, so
as to show patches of the under strata surrounded by these upper strata.
The first of them are peculiar to the tracts proper to the lower strata (when
not occasioned by a sudden lift of the strata), and are called Hummocks; the
other, when not occasioned by a sudden sink of the strata, are found only in
the tracts proper to the upper strata to those detached" (Farey).
Whenever a vein occurs underneath a Toadstone bed it is seldom of the
*W. Topley and G. A. Lebour.
CHAP. I.]
LEAD ORE IN TOADSTONE,
243
same width, or of the same nature exactly as that above it, nor are they
directly under each other, although generally they follow about the same
range. Veins with such deviations are said to be squinted or leapt aside,*
and this deviation is in some instances so considerable, that lawsuits have
arisen to determine whether they are the same veins or not. The occurrence
of lead ore in Toadstone is rare. There has been an opinion that this mineral
is found in Limestone only, but this idea has been somewhat too hastily
adopted. In the neighbourhood of Matlock, at the Side mine, under the High
Tor, and at the Seven Rakes mine, on the right side of the river, not far
from the bridge, this ore has been severally worked. The vein in the Seven
Rakes mine was formerly worked to the depth of about thirty fathoms in
the first Limestone, when, on coming to the Toadstone, the work was
abandoned, as it was supposed that the vein was cut off by that bed. Some
years afterwards a level was driven into the hills from near the river to carry
off the water, and the vein was worked in the second Limestone, underneath the
Toadstone, which was left untouched. The vein was again abandoned when
the workings were carried to a depth at which they could no longer be kept
clear from water. But in 1819 five working miners took a set of the ground,
in order to work the vein in the intermediate Toadstone, which had been left,
and the undertaking proved profitable.¸
The owner of the Side mine stated that the veins in all cases with which
he is acquainted are continued through the Toadstone, and frequently change
their degree of inclination in passing through that rock, and that sometimes
after such a change in inclination the vein again returns at an abrupt angle,
like a V placed horizontally. Frequently the lodes do not bear well in this
Toadstone.t
The following names have been applied to the Toadstones in Derbyshire: .
amygdaloid, black clay, basalts, boulder stones, brown stone, cat dirt,
channel, chirt, clay, dunstone, ferrilite, fiery dragon, freestone, jewstone,
ragstone, trap, tuftstone, whinstone, secondary traps, and others.
Dunstone (a term used by Mr. W. Hopkins, but not generally adopted).—
There exists in the neighbourhood of Matlock, on Middleton Moor, by
Wirksworth, to the east of Newhaven, and in some other places, a formation
known by this name. It is different from Limestone, inasmuch as it contains
a very small portion of calcareous matter; and that, as a geological forma-
tion, it is not identical with the Toadstone is rendered conclusive by the circum-
stance of its being in many places as distinctly stratified as the Limestone itself.
Mr. Hopkins regards it, "therefore, as a distinct formation, any one continuous.
bed of which must have had its particular epoch of deposition. If the epoch
of the formation of the first Toadstone occurred after that of the Dunstone
bed, this latter will lie entirely in the second Limestone, so that though of two
continuous beds of Dunstone (supposing them to have had different epochs
of deposition) one might possibly be in the first and the other in the second
Limestone, neither of them could lie partly in one, partly in the other.
* Werner was of opinion that the Toadstone occasioned the squinting of the veins or their being
“thrown to a side" by its very unequal thickness and hardness. See "New Theory of Veins," p. 129.
† See "Notice accompanying Specimens of Lead Ore found in Toadstone from near Matlock,
Derbyshire." By Charles Stokes, Esq., F.R.S. ("Transactions of the Geological Society," Second
Series, vol. i. p. 163.)
R 2
244
[BOOK II.
THE FORMATION OF DEPOSITS.
"The stratification of the Dunstone* cannot always be easily recognised,
but the most obvious instances may be found at the upper end of Gratton
Dale and on Middleton Moor, by Wirksworth, in both which places it gives
to the scenery a peculiar wild and striking aspect. I have sometimes
remarked the Toadstone as being laminated, but it never presents the
remotest trace of stratification.” †
YORKSHIRE.—The principal ores produced by the Mountain Limestone of
Yorkshire are sulphide of lead (galena), sulphide of copper (yellow and grey
copper ore), sulphide of iron (pyrites, mundic), sulphide, carbonate, and
oxide of zinc (blende, black jack, &c.). Iron ores are also found. These ores,
excepting iron, are all connected with spar veins, fissures, or rock dykes.
No instance is known of any one vein being continuous from the Slates of
Cumberland into the Mountain Limestone tract. No case, remarks Professor
J. Phillips, is known of any vein being worked in the Old Red Sandstone; no
vein has been worked in Yorkshire above the Brinham Millstone Grit,
though lead ore has occurred in veins in coal seams above that rock, and
strings and nests of lead ore and copper ore have been met with in
Magnesian Limestone at Nosterfield, Farnley, Newton Kyme, and Warms-
worth. Calamine, and white oxide of zinc occur, chiefly in the lower Scar
Limestone in Bolland, near Whitewell, and at Mallam. South of Wensley-
dale it is in the lower Scar Limestone principally that the lead mines of
Greenhow, Nidderdale, Grassington, Kettlewell, &c., have been worked, but
to the north of Wensleydale the Scar Limestone becomes the most productive.
In the mining districts of Greenhow, Grassington, and Kettlewell veins
yield ore both in the Limestone and Millstone Grit series. Veins have been
found more or less productive in the Millstone Grit series south of Lother-
dale, and in the line of the Auldgang (Old Gang) vein in Swaledale and
Arkendale. Mines are worked in the Whin-sill at several points north of
Maize Beck.‡
Mr. Thomas Sopwith observes of Yorkshire: "Most veins in the mining
districts preserve a tolerably direct course for a considerable distance, some,
indeed, for several miles." (We are disposed to think this requires further
examination). "They are commonly designated veins, cross veins, and
quarter-point veins. The former are sometimes called right veins, their
course being east and west, or a little north of east and south of west. Those
which have a bearing nearly north and south are called cross veins. The
few veins which have a bearing between these are called quarter-point veins.'
The relation of "hade and throw" must now be noticed. A general
law has been accepted by miners and colliers to which in secondary
strata few exceptions have been found. It may be thus expressed: The
'slip" or plane of dislocation hades, dips, underlays, or is inclined to
the vertical so as to pass under the depressed portion of the strata which
are displaced.
Thus A is the downcast or depressed set of strata, and B the upcast (it
* A manuscript note-which is recognised as the handwriting of Sir Henry de la Beche—says, "It is,
I find, a Magnesian Limestone."
+ "On the Stratification of the Limestone District of Derbyshire." By W. Hopkins, M.A. 1835.
Printed for private circulation.
"Illustrations of the Geology of Yorkshire." By John Phillips, F.A.S., F.G.S. 2nd edition. 1833.
ވ
CHAP. I.] MOUNTAIN LIMESTONE AND MILLSTONE GRIT. 245
must not be supposed that any upward movement was necessary), v v the
plane of dislocation, inclined from v to v the vertical so as to dip under the
downcast side (Fig. 29).
In mining language the beds are highest on the ledger (lower) side of the
vein, and lowest on the langor (upper) side.
The width of the fissures varies
with the character of the rock,
being open in Limestone, con-
tracted in Gritstone, but much
reduced in plate.
The Great Limestone of Alston
Moor can be traced to Limedale
in Yorkshire, and to Wensleydale,
where it is commonly called the
"Twelve-fathom Limestone."
Upcast
Downcast
Booooo00000
Extent of Throw
Dip
oooooooo
side
Side
v
Fig. 29.
A
The section of the Mountain Limestone and Millstone Grit in Wensley-
dale is thus given by Professor Phillips :-
MILLSTONE
GRIT SERIES.
UPPER LIME-
STONE BELT.
FLAGSTONE
SERIES.
SCAR
LIMESTONES.
Coarse and fine Sandstone, shales, and coal
•
Coarse, fine, and slaty Sandstones, shales, cherty beds, and coal
Millstone grit of Ingleborough, shales, cherts, and coal.
Thin Limestone, Sandstone, and shale .
Main or 12-fathoms Limestone, shales, Sandstones, and coal 200
underset Limestone
""
}
pai}
700 feet.
Alternations of flagstones, of various quality, in great abundance,
with shales, coal, hard gritstones, and three or four strata of
Limestone from 6 to 30 feet thick. The black marble of Dent is
nearly at the bottom of this group
Limestones of great thickness, with partings principally of shale
•
500
500",
The "twelve-fathoms Limestone" is comprehended in the central part
of the upper Limestone belt. From this it is evident that the dis-
tance from the bottom of the Scar Limestone does not differ materially
from that intervening between the bottom of the Melmerby Scar Limestone
and the Great Limestone as developed in Cumberland. This thickness
also corresponds with that of the mineral Limestones and Toadstones of
Derbyshire.
The following remarks may be viewed as mainly those of Professor
Phillips. They are abstracted from his admirable treatise on "The Geology
of Yorkshire," more especially the second part, which treats of the Mountain
Limestone district. Although not disposed to receive all his positions as esta-
blished, yet they are deserving of the closest attention, as the conclusions
of a most accurate observer and of a thoughtful mind.
From the facts above mentioned it follows that the dependence of par-
ticular metallic products on particular series of rocks is principally a local
phenomenon without general application; but, on more minute analysis of
the phenomenon, it is found that in a given district certain beds generally are
and others generally are not productive of metallic treasures. A particular
vein, for example, in Swaledale traverses Millstone Grits, plates, and cherts;
Main Limestone, grits and plates; undersill Limestone, grits, plates, &c.;
and it is a matter of experience that among these beds only the conso-
246
[BOOK II.
THE FORMATION OF DEPOSITS.
lidated silicious and calcareous beds are productive; in the argillaceous
plates the veins are mostly "dead."
If in consequence of the displacement of beds along the vein solid rocks on
one cheek are opposed to argillaceous beds, the veins (unless very strong) will
probably be unproductive.
The Limestone district of the north of England produces but little copper.
Conishead Priory, Alston Moor, and Middleton Tyas are exceptions. It is
remarkable that there is a line of mineral deposits passing north by west,
parallel to the eastern range of the carboniferous deposits, principally yield-
ing copper ore in Magnesian Limestone at Newton Kyme and Farnley, and
in Main Limestone at Middleton Tyas.
Swaledale, in Yorkshire, is distinguished especially by its Mountain
Limestone formation. Millstone Grit caps most of the highest hills; the
sixth-set Limestone, with a considerable thickness of alternate bands of grit
and plate under it, forming the lowest observable Limestone beds in the dale.
The characteristic deposits are of the following thickness :—
Limestone
Chert
Grit
Plate
•
•
calcareous
silicio-calcareous
silicio
argillaceous
•
45 fathoms.
15
""
75
"
40
"9
175=1050 feet.
The chert beds are distinguished by the names of the "Crow Chert," the
"Main Chert," and the "Underset Chert."
The grit is a highly silicious and often micaceous deposit. When worked
freely it is called Freestone. It consists of three parts of silicious sand, with
one of mica and oxide of iron. The chert beds are uncertain in the pro-
duction of the ores of lead to the Limestone beds; but the grits of Swaledale
are usually unproductive.
The plate, or shale, is an argillaceous deposit of a more or less fissile
structure often containing fossils.
The grits and plates may be regarded as the unproductive or non-metal-
liferous deposits.
The Limestones and cherts are the lead-ore-producing beds. The main
chert and Limestone are by far the most valuable lead-ore-producing beds
throughout Swaledale.
CUMBERLAND AND WESTMORELAND.-In the north of England the Moun-
tain or Carboniferous Limestone forms a very distinct and easily recognised
series of rock. Geologists have given a total thickness of 2,800 feet to it in
the northern counties, and it consists of a series of alternating strata of Lime-
stone, Sandstone, Shale, intersected by Trap rock. In the mining district of
Alston Moor the aggregate thickness of these rocks is 1,037 feet, consisting
of 183 feet of Limestone, 349 of Sandstone, and 505 feet of Shale. A layer of
basaltic rock may be considered as forming the base of the Alston Moor
mineral strata. In these rocks the metalliferous ores of lead are found to
occur. The accompanying section of the strata at Tees-side and Troutbeck
mines gives a faithful description of that formation.*
*"The Laws which regulate the Deposition of Lead Ore in Veins on Alston Moor."
Wallace. 1861.
By William
SECTION OF ALSTON MOOR.
CHAP. I.]
1.
Limestone.
2.
Slaty Hazel.
3.
Scar Limestone.
4.
Post and Hazel.
5. Ditto.
6. Hazel.
7. Plate.
8. Post Limestone.
9. Hazel.
IO.
Plate.
II. Tyne Bottom Lime.
Whetstone Beds.
12.
13. Whin.
14. Hazel.
15.
Limestone.
16. Plate.
17.
Jew Lime.
247
In the Tees-side district a greater thickness intervenes between the top of
the Whin-sill and the bottom of the Scar Limestone than in the Garrigill
district, but in the latter the whin is considerably thicker than in the former,
and the distance in each case between the bottom whin and the bottom of
the Scar Limestone is very nearly equal. The copper hazels are also better
developed in the Tees-side than in the Garrigill district. At Long Clough
mine the firestone stratum is 54 feet in thickness, but not more than half a mile
in a north-west direction it only exists as a thin bed of famp,* while the iron-
stone in the same district increases from a few inches to a stratum of a very
hard Sandstone 12 or 14 feet thick. The Limestone strata vary but little in
thickness throughout wide areas. The beds of Shale vary more than the
Limestone, and the Sandstones vary to a still greater extent. The Lime-
stones usually repose upon a bed of Sandstone; if a bed of Shale intervenes it
is rarely more than a few inches in thickness.
The original state of the strata over this district was no doubt
horizontal, or nearly so. Now the beds are nearly all in an inclined position.
This varies considerably, but on the line of the greatest acclivity forms an
angle of about 2° 15'. The average bearing of this rise is 30° west of south
from the true meridian.†
The following gives a general sketch of the strata of the district :-
The Great Limestone divides the strata into two portions; the upper one
consisting of alternate silicious and argillaceous beds with only two thin
beds of Limestone, while the under portion contains calcareous strata of
considerable thickness.
The Grindstone Sill, about 4 fathoms thick.
stratum at Allenheads, Coalcleugh, and Rampgill.
This is the highest
The Fell-top Limestone is the first or highest calcareous stratum that
occurs in the mining district. It is called the green Limestone near Alston.
It is too thin to be of consequence in mining, seldom exceeding 4 or 5 feet.
The Crow Coal.-A thin seam of coal of inferior quality occurs under this
Limestone. A mixture of this coal and clay is formed into balls, called cats.
The Upper Coal Sill.-A silicious stratum varying from 1 to 2 fathoms
in thickness.
The Whetstone Sill.-A plate bed of considerable thickness (from 5 to
8 fathoms), and under this
this another hazel occurs which is used for
sharpening scythes.
* A name given to variable beds of decomposed Limestone.
+ Thomas Sopwith, "An Account of the Mining District of Alston Moor;" W. Millar, "Mines of
Carlisle," 1800; Westgarth Forster, "A Treatise on a Section of the Strata from Newcastle to
Crossfell," 1801; Dickinson and Sopwith, "Plans of Holyfield and Hudgill Cross Vein Mines,"
1828; Wallace, "Mineral Deposits;"-are the only important publications relating to Alston Moor
mining.
248
[BOOK II.
THE FORMATION OF DEPOSITS.
The Upper and Lower Slate Sills, commonly called grey slate, used for
roofing slates and flags, about 4 fathoms in thickness.
The Firestone Sill.-A silicious stratum about 6 fathoms in thickness.
Its colour is a coarse reddish grey. Both the earthy and the metallic
contents of veins in traversing this stratum attain their maximum specific
gravity. Sulphate of barytes is more common in this than in any other
stratum in Alston Moor.
Pattinson's Sill lies from 10 to 12 fathoms below the Firestone. It
derives its name from the miner who first sunk into it at the Rampgill vein.
Lead veins have often been productive in it.
The LittleLimestone is the second calcareous stratum in this mining field,
lying about 46 fathoms below the Fell-Top Limestone and from 10 to 12
fathoms above the Great Limestone. Mineral veins have often been very
productive in this stratum.
The High and Low Coal Sills.-Two hazels accompanied with thin seams
of coal of inferior quality.
The Great Limestone.-The thickest Limestone worked in Alston Moor,
and by far the most productive in mineral treasures. In the Great Limestone
there are three different flats. These flats vary in thickness from 1 inch
to 6 feet, and Mr. Leithart, an excellent authority on this district, says:
"There have been instances of all the flats being so thick at the same place
as to form one whole mass of flat from the top of the high flat to the bottom
of the undermost one."
The Tuft or Water Sill is about 10 feet thick and is dull-red coloured,
containing much oxide of iron. Many veins which have been productive in
the Great Limestone have been also productive in this.
Limestone Post.-A thin stratum of impure Limestone about 18 inches
thick. This is an equivalent of the underset Chert of Swaledale. Great
inconvenience is often experienced in working through this thin stratum on
account of the quantity of water which it contains.
The Quarry Hazel.-A dull-red-coloured Sandstone containing some
mica, varying in thickness from 1 to 5 fathoms. It has sometimes proved
productive of lead. This stratum is sometimes divided by a famp bed, con-
sisting of mica, silex, and argillaceous matter. Beds called grey beds are
found at the bottom.
Girdle or Till-bed, is a kind of chert, from 3 to 5 yards in thickness,
sometimes divided into layers or posts. Veins that have been productive in
the four-fathoms Limestone have generally continued so in the till-bed. Mr.
Leithart remarks that the metallic contents of the veins in this stratum are
usually pure and solid.
The Four-Fathom Limestone derives its name from its thickness, which
it preserves more uniformly than any other stratum on Alston Moor.
Veins which have been productive in the Great Limestone have frequently
proved less rich in lead in this Limestone, but they frequently contain the
sulphide of zinc. Many trials have been made in this stratum, but they have
not usually been satisfactory; when they have been so, the ore has proved
rich in lead, but the lead has not been very argentiferous.
A seam of coal is found under this of about a foot in thickness.
CHAP. I.]
THE WHIN-SILL OF CUMBERLAND.
249
The Nattrass Gill Hazel.-A coarse dull red and white Sandstone. In a
mining point of view it is not important, the veins being generally barren.
The Three-Yard Limestone.-A bright blue Limestone containing few, and
these generally unproductive, veins.
The Six-Fathom Hazel.-Veins in this have not generally proved productive.
The Five-Yard Limestone.-Impure and flinty veins unproductive in it.
The Slaty Hazel.-Sometimes called Gossop-gate hazel. Very few veins,
and those not productive.
The Scar Limestone.-Its thickness is from 5 to 9 fathoms. Its name is
derived from the bold precipitous face which it presents, being in many parts
most picturesque and romantic. Veins have not proved productive in this
Limestone.
The Tyne-bottom Plate is extremely hard. The metallic contents of veins
in this stratum are generally dense and pure. Under this is the lowest
calcareous stratum exposed in Alston Moor.
The Tyne-bottom Limestone, a hard flinty Limestone. Its veins are rarely
productive.
Under the series of strata described appears a range of basaltic rock
locally called the Great Whin-Sill. It is very variable in thickness.
At Hilton, in Westmoreland, it is 4 fathoms thick.
At Dufton, 7 to 8 fathoms.
At Silverband, 20 fathoms.
At Cauldron Snout, on the Tees, 30 fathoms.
At Tyne-bottom mine, near Garrigill, it is worked into for nearly
20 fathoms.
At Settlingstones, near Haydon Bridge, it occurs at the surface, and the
shaft is sunk in it to a depth of 22 fathoms.
This rock is now usually considered as of intrusive origin. Williams, in
his "Mineral Kingdom," argued that such rocks were regularly deposited
in the same way as the stratified series; but this is no longer admitted.
Professor Sedgwick objects to the term Whin-Sill, because sill indicates a
regular stratification of this rock.*
Mr. T. Sopwith says: "The insertion of basaltic rocks among the
regular strata at Teesdale is a fact open to the observation of every eye at
the waterfall of High Force. In the mine of Silverband, nearly two miles
higher up the Tees, the author has descended a shaft sunk through regular
strata to the whin-sill, in which the miners were then raising lead ore. The
superincumbent strata here are considered to correspond with those which
rise on the Whin-Sill at Alston."†
The so-called Toadstone of Derbyshire exhibits a very marked similarity
to the Whin-Sill of Cumberland, and both possess many characters in
common with the Elvans of Cornwall.
THE LAKE DISTRICT.--The rocks of the Lake District in England are
Cambridge Philosophical Transactions."
Sopwith, "An Account of the Mining Districts of Alston Moor." 1833. The late Mr. T. Sopwith
favoured me with the following remarks on this rock: "The most important igneous rock connected
with our lead-mining veins is what is locally called the 'whin-sill,' varying in thickness from 20 to 50 or
more fathoms, and in this irregular thickness interposed over large tracts of country between regularly
stratified beds of Limestone, Sandstone, and Shales. Into this basaltic rock lead veins penetrate or continue
downwards from the regular strata, indicating a formation posterior to the intrusion of basalt."
250
[BOOK II.
THE FORMATION OF DEPOSITS.
Granites, hornblendic Granites, quartz-felsites, and felstones. These are
divided by the late Rev. J. Clifton Ward into several well-defined rocks,
which may be thus described.*
The Skiddaw Granite is seen in the course of Sinen Gill, between Skiddaw
and Blencathra, and is no doubt connected beneath with the larger mass of
the Caldew, a mile and a half to the north. It consists of a white felspar,
dark mica, and intersticial quartz.
The Wastdale Granite, or Eskdale Granite, occurs at Wastdale head, where
it spreads over a small tract at the foot of Kirkfell and Lingmell. The pre-
vailing tint of the rock is reddish, being coloured by the felspar, and the
mica is dark. The Wastdale Granite sends off quartz felsite (elvanite) in dykes
which correspond with the Cornish elvans.
The Ennerdale syenitic Granite occupies a large area, is tolerably uniform
in appearance, and is usually red in colour, and assumes à more sombre and
grey hue from the increased quantity of hornblende and mica, and less decided
colour of the felspar; in such cases it is usually more fine-grained.
Diorites.-In connection with the Skiddaw slates and volcanic series are
many small bosses and dykes of intrusive rock.
Dolerites, in a very highly altered state, are common. Some of these
intrusive rocks are immediately connected with the plumbago mine.
The Skiddaw Slates are traversed by many faults. Most of these have a
north and south, or north-north-west and south-south-east direction. It is
quite unnecessary to describe here those faults which have no apparent
connection with the mineral veins; such as disturb the lodes will be
noticed.
DURHAM AND NORTHUMBERLAND.-The Great Limestone has been traced
eastward in the Derwent mines to the western side of Cross Fell. It is seen
at the surface on the north side of the Tyne, in the mining district of Haydon
Bridge, where the beds known as the Tumbler beds are separated from the
more compact Limestone by a thick bed of Shale and another of Sandstone.
The following is the section of the strata at Fallowfield :-
SOIL, CLAY, &c.
1. Plate and girdle beds
Bastard Lime
2. Grey beds Coal ditto
3. Ditto
4. Sandstone
5. Grey beds
Ditto
Ditto
6. Sandstone
7. Girdle beds
8. Grey beds
9. Hazel
10. Grey beds
Sandstone
coal.
•
•
•
dark-coloured post
II. Little or coal lime
·
42 feet.
II
12
""
25 ",
32,
14. Bastard lime
15. Hazel
SOIL, CLAY, &c.
12 feet.
38
16. Light-coloured lime
17. Hazel, &c.
18. GREAT LIMESTONE
•
21. Grey beds, white post
splint coal
22. Strong hazel
9
""
69 "
Plate. 87
{Plate : 38
Lime
""
""
64,,
Plate. 72 ""
Lime. 2I
28 ""
14 ""
3
{'
240",
24
""
""
19. Grey beds
70",
20. Limestone
34",
24
""
37
""
10
57
•
•
23. Tyne-bottom lime
17
Whetstone bed
12. Hazel
13. Grey beds
FALLOWFIELD COAL,
5 feet 8 inches
20
""
26. Jan Limestone.
""
•
I.
24. WHIN
4/2
180
•
""
25. Hazel
30
"
24
In the Magnesian Limestone, in the cuttings of the Stockton Railroad,
near East Frickley, these cells are lined with crystals of carbonate of lime,
* See "The Geology of the Northern Part of the English Lake District." By the Rev. J. Clifton
Ward. ("Memoirs of the Geological Survey.")
From W. Forster's)
"Section of the
Strata," 1882.
B
01
A
CHAP. I.] CARBONIFEROUS LIMESTONE AND WHIN-SILL. 251
occasionally associated with small but beautiful crystals of sulphide of lead
and sulphide of zinc.
In a quarry near Coundon, in the bottom beds of Limestone, they find
crystalline nodules of sulphate of barytes, with sulphides of lead and zinc,
irregularly deposited through their mass (Sedgwick).*
*
No. 5 is unquestionably a bed. The galena is not a water-worn mechanical
deposit, but is apparently contemporaneous.
From a quarry (called Seven Acre) between Chesterfield and Well,
Professor Sedgwick gives the following section:-
1. Strong yellow cellular Magnesian Limestone, forming base of the quarry
2. Thin shattered beds of a brownish-blue colour, with thin seams of marl
3. Earthy, yellowish bands
4. Dark brown and black Shale, highly calcareous and semi-indurate
•
•
•
12 feet.
5. Yellow nibbly Limestone, much mixed with earthy impurities, and containing
a considerable quantity of galena (sulphide of lead)
6. Dark Shale
7. Yellow Magnesian Limestone (?)
3 or 4 feet.
I foot.
•
5 inches.
I foot.
3 feet.
The following sections of the Carboniferous Limestone series will show
position of the Whin-Sill (Fig. 30). The description accompanying the wood-
cut will sufficiently indicate the position of the basaltic rocks of Northum-
berland.
Alston Moor
(Cumberland)
C
HOMELITO
ONLARIN
LIMESTONES
COALS
BASALT
WHIN SILL
Weardale (Durham)
Crag Lough
(Roman Wall)
ΙΟ
Gunnerton
6
Bavington
5
Greenleighton (a)
Dikehead (b) and
Fallowlees Burn (c)
5
Wards Hill
9
Rugley
C
b
[amuminu
C
Fig. 30. Sections of the Carboniferous Limestone Series of Northumberland, showing the Positions
of the Whin-Sill. Scale 400 feet to I inch. The figures give the distances, in miles, between the places.
A Great Limestone of Alston Moor, Weardale, and South Northumberland; the 10-yard Limestone
of Alnwick District. B=4-fathom or 8-yard Limestone. C = 3-yard Limestone of Alston Moor
and South Northumberland; the 6-yard Limestone of Mid Northumberland. D Tyne-bottom Lime-
stone of Alston Moor.
*Professor Sedgwick, F.R.S., "On the Geological Relations and Internal Structure of the Magne-
sian Limestone," &c. &c. ("Transactions of the Geological Society of London," Second Series, vol. iii.)
TEETKAL KELIS
5
a
Harlow Hill
Snab Leazes
252
[BOOK II.
THE FORMATION OF DEPOSITS.
The two following sketches (Figs. 31 and 32), which are from the "Geo-
B2
L
E
W
B1
L
B
B I. Western Į
B 2. Eastern
Whin-Sill.
LL. Limestone of the Northumberland Carboniferous Limestone Series.
Fig. 31.-Sketch Section across both Branches of the Whin-Sill, showing their probable Mode of
Connection near Great Bavington (about 2 miles).
S.W.
I v n
I'
SL
B
کہL
114
州
​ار
N.E.
11. I
ASL
L
B
B. Branch of Whin-Sill, 3 to 4 ft. thick (exposed at intervals),
sending strings of basalt into the Limestone.
L. Bed of impure Limestone.
SL. Saccammina-beds.
L. Good Limestone.
Fig. 32.-Sketch in Elf-Hills Quarry (1st August, 1871).
rated as those of Northumberland and Cornwall.
B
logical Survey Memoirs,"
will serve for comparison
with the drawings of the
Elvan courses in the Cornish
mines. The general con-
ditions will be so evident,
that no further descrip-
tion will be required to
show the close analogy be-
tween these two varieties
of Trap rocks as they occur
in districts so widely sepa-
SHROPSHIRE AND CENTRAL WALES.—A small section only of Shropshire
demands our attention. The mineral deposits are confined almost entirely to
the Stiperstones range, which Sir Roderick Murchison placed at the base
of his Silurian system. Sir C. Lyell groups these rocks under the Lower
Llandeilo formation; and Professor Sedgwick calls them Arenig; thus the
question arises, owing to the absence of fossil fauna, can the geologist draw a
definite line between the Stiperstones and the Llandeilo flags, or a vast
thickness of rock below which was seen to form the Llongmynd Hills, and was
called "unfossiliferous grauwacke?" A glance at the map of the Geological
Survey will show that the metalliferous district around Shelve consists of
the Llandeilo flags and Sandstone, bordered by the Wenlock shale and
the Upper Llandovery rock. It will also be seen that the Llandeilo flags
are marked with intrusive masses, with lines of Greenstone, and long intrusive
bands of the Felspathic ash. The mineral veins are very irregular, a con-
siderable number running from north-east to south-west, others again from
south-east to north-west, and a few nearly north.
If a line is drawn around Shelve for about five miles westward and three
miles eastward, five miles to the south and four miles to the north, we
include all the important portions of the mineral field.
The geological relations of these districts are of a rather complex
CHAP. I.] METALLIFEROUS DISTRICTS OF CARDIGANSHIRE 253
character. In the first place, the Slate rocks are interstratified with great
beds of black shale, similar to the carbonaceous shale so frequently met with
in connection with mining in the upper beds of the Carboniferous Limestone,
which are in the great deposits of lead. Sometimes these shales are mere
bands about a yard wide, but at other places they seem to be hundreds of
fathoms thick, so that coming upon shale is generally coming upon rich
courses of ore. These larger beds of shale have a definite course through
the country, in some places occupying large troughs in the Slate rocks.
Besides this occurrence of shale we have sudden changes in the character
of the Clay-Slate, which favourably affect the lodes. In a rock formation
which contains the Stiperstones range it is, of course, by no means surprising
that we should occasionally find bands of quartzose matter, and, in fact,
certain beds of the Slate rocks not unfrequently become arenaceous in
character. Lastly, there are Greenstone dykes and interstratified horn-
blendic and felspathic bands.
The lead-bearing district of Shropshire is closely allied to that of Mont-
gomeryshire, and, indeed, of Central Wales. The rock in which the lodes of
this district occur is of Lower Silurian age, and of that general mineral
character which we call Clay-Slate. This Clay-Slate is, traversed throughout
the whole length of the metalliferous district by that well-known band of inter-
stratified quartzose rock which, from its comparatively greater power of resist-
ing denuding action, stands out prominently above the neighbouring strata,
forming the picturesque ridge of the Stiperstones. This ridge bears 30º
south to 35° west (true bearing), and dipping north-west; and the lead district
is found to be generally in this direction-to the north-west, or direction of
the dip of the Stiperstones. About two miles north-west of the Stiperstones,
and running nearly parallel with it for some distance, there is the low range
forming the Shelve Hill, a little beyond which the lodes seem to die out.
The metalliferous district of Cardiganshire and Montgomeryshire is a
tract exclusively of Clay-Slates and Gritstones, corresponding with the lower
beds of Murchison's Silurian system. The prevailing strike of the beds
is from north by east and south by west, to north-north-east and south-south-
west, and in the same direction bands of various widths may be traced,
in which many important lead mines have been worked.
This district differs in a striking manner from those in which we have
dissimilar rocks. There is not anywhere the appearance of any rocks of
igneous origin. All the beds are evidently of one geological age, or rather
the differences in the rocks are so slight that it is quite impossible to
determine the relative age of any set of beds.
The appearance of the veins at their "outcrop" are so uniform that the
miner has no changes of colour, due to decomposition or otherwise, to
indicate the riches below.
A tract of land stretching along the sea-coast for about four miles on the
north of Aberystwith and twelve miles from Aberaeron is destitute of
mineral veins. The high range of mountains to the east and north of Tre-
garon, of the chief group of Plymlymon Fawr, of the hills east of Llanidloes,
and of the plateau between that town and Llanbrynmair, are in like manner
distinguished by the absence of mines. A portion of the two counties
254
[BOOK II.
THE FORMATION OF DEPOSITS.
being thus distinguished, varying in lithological character from a soft
shale and argillaceous rock to a coarse gritstone and conglomerate, is free
of
any mineral deposits. The productive mines are generally parallel to the
run of the undulations of these rocks. These zones may be divided into
six groups, which are thus satisfactorily defined by Mr. W. W. Smyth, who,
as mining geologist to the Geological Survey, examined with the utmost care
this interesting district* :—
"The first group, beginning on the west, borders on the unproductive
grits of Aberystwith, and includes the mines of Tal-y-Bont, Penybontpren,
Llancynfelyn, and Tre-'rddol, producing lead ore containing a very trifling
amount of silver, a little zinc-blende, and in two or three instances copper
pyrites. The lodes are of small width, and the strata, with, a moderate
westerly dip, are perpetually running into the fissile variety of slate, which
injures the regularity of their metallic contents.
"The second is a band of greater importance, which about two centuries
ago, when known as the 'Welsh Potosi,' returned enormous wealth to the
enterprising adventures of Sir Hugh Myddleton and Mr. Bushel, while at the
present day it is distinguished by the mines of Goginan, Cwm Sebon,
Cwm Symlog, Daren, Pen-y-Cefn, and Esgair-Hir. The Slaty rocks here
assume a paler tint, inclining to a bluish and greenish grey, offer a peculiar
and almost greasy lustre and exhibit on the whole a more massive
bedding, in consequence of which it would appear that the mineral veins
increase in width, expanding in some cases to upwards of 20 feet; the
lead ore is generally argentiferous, sometimes to the amount of 38 ounces
in the ton of lead.
"The third division, ranging from Ystrad Meyric to the Devil's Bridge, and
along the course of the Rheidol, comprehends a number of mineral veins,
varying in character nearly as much as the rocks which they traverse; thus
Llwyn Malys lode is remarkable for containing a small percentage of silver,
though at a distance from other argentiferous mines; Fron-Goch for its
large deposits of galena and zinc-blende; the Estymteon lode for its bands
of iron pyrites; and that of Pen Drosgol for its manganese ore; whilst the
beds exhibit every variety between the Gritstones of the Mynydd Bach and
of Drosgol, the dark fissile Slates on which various quarries have been
opened, and the indurated grey argillaceous rock in which the mines
generally occur.
"The fourth band, striking from Lampeter to the central range of Plym-
lymon, will include the highly argentiferous lead lode of Llanfair Clydogau,
and then, after an interval of some miles on the north, several of the localities
most productive of common lead ore, accompanied by zinc-blende and calc-
spar, the principal mines being known as Esgair-y-Mwyn, Logaulas, and
Nant-y-Creiau. To the north of Plymlymon Fawr, where the beds for the
most part consist of fissile shales and gritstones, not a trace of ore has yet
been discovered.
“The fifth zone, ranging along the east of the Plymlymon ridge, comprises
the remarkable and extensive mines of Cwm Ystwith, some slightly worked
veins in the upper valleys of the Wye and Severn, the important works of
*"On_the_Mining District of Cardiganshire and Montgomeryshire." By Warington W. Smyth,
M.A., F.R.S., F.G.S. (" Memoirs of the Geological Survey of Great Britain,"´vol. ii. part 2.)
255
CHAP. I.]
THE MINING DISTRICT OF SHROPSHIRE.
Delife and Esgair Galed, and the group of parallel lodes near Llanbrynmair.
Beginning with the elevated mass on which the Teifi pools are situated, the
southern part of this division is marked by a frequent intercalation of
arenaceous matter, which to the north of the Delife mines is succeeded by
argillaceous shale; whilst it is remarkable that, throughout the former area,
copper pyrites is so common a constituent of the lodes as to have been
separately returned from several of the mines, as Copper Hill (Cwm Ystwith,
Siglen Las, Hafod Feddgur, Cwm Rhicet, and the Delife.
"The sixth division, circumscribed as it is on the east and north by the
gritty beds which crop out from beneath the Wenlock shales, comprehends a
few mines round Llanidloes, as Byrn Dail, Pen-y-Clyn, and the Gorn; but
these are characterised by the remarkable fact that the ore of lead is accom-
panied by witherite and baryte, neither of which minerals have yet been met
with in any other part of the district we have considered.
"In the same zone might be included another group of plumbiferous veins
occurring in a remote part of the county around Llangynnog, at a distance
of nearly thirty miles from those above mentioned. They traverse the Slaty
rocks where they emerge, in their regular line of strike, from the superin-
cumbent grits which form the dreary tract dividing the drainage of the Dyfi
from that of the Fyrnwy and Banw; * and their relationship is further proved
by the ores of lead and zinc being associated with the same minerals of baryta.
An essential difference is, however, to be remarked in the frequent intercala-
tion of beds of felstone porphyry and gritty rocks of volcanic origin among
the Slates, a fact which bears in a marked manner on the distribution of ores."
The lead-mining district of Shropshire is geologically a part of the great
mining district of Montgomeryshire, the resources of which are best shown
by what has been done by the Van mine. As to the district itself, we
have no hesitation in saying that for its extent-for it is only a small
district-it is unsurpassed by any district in the United Kingdom, or
as a lead-mining district probably in Europe. The most important mine is
Snailbeach, which has been worked ever since the last century, and has
made immense profits for about ninety years, having on an average raised
2,000 tons of lead ore a year. It may be considered as one of the most
important lead mines in the kingdom. Although a few years ago Minera,
in Denbighshire, was a richer mine, and at present. Van, in Merioneth-
shire, is so, yet taking into consideration the permanence of its working,
and the length of time it has been making profits, it will probably be
found that Snailbeach has yielded larger returns than any other lead mine in
England.
Adjacent to this is Perkin's beach mine, where, some years ago, a fine
deposit of lead was found near the surface, and 3,000 tons of lead ore were
raised out of the workings, which were then about 70 fathoms deep. There
are four principal veins in this mine, which run a little to the north of cast and
to the south of west, with a southern underlay. There are also four powerful
caunter veins running very nearly north and south, with south-westerly under-
lays, each producing ore. The first, second, and fourth veins run parallel
* "In this district, also, a few metalliferous veins occur in the region of the arenaceous rocks alluded
to as at Moel Uchlas, near Can Office and Bwlch Creolem, near Llangynnog; but the trifling operations
hitherto carried on upon them yield no data of importance."-W. W. S.
256
[BOOK II.
THE FORMATION OF DEPOSITS.
to the Snailbeach lode, which has been worked with much profit for more than
fifty years.
The first and second caunter lodes are bold and well defined. From the
latter upwards of 600 tons of ore were raised in a very limited space, in the
back of the deep adit level. More than 200 tons have also been obtained from
the first caunter lode.
The Adit Mouth vein is also a very good one, Pugh and Gwilliam's sump
being on it, from which a great deal of ore has been got. Good ore was cut
it crossing through it north from the Big Spar vein which intersects Cross's.
The Big Spar vein is a great champion lode that can be traced on
the surface from the extreme east of the mine to and beyond the boundary
of Oven Pipe, an adjacent mine. It is composed of lime-spar and sulphate
of barytes and spots of ore.
On Cross's lode upwards of 2,000 tons of ore were got from the surface
to about the middle adit level, and the pipe of ore made rich up to the sod.
In a point about the middle adit the surface pipe of ore forked, owing to
the Elvan, in which it was, being interfered with by the blue Slate which
entered the vein, and threw the so-called Elvan north. The general opinion
is that the ore was carried north with it, and would be found on the lying
walls of the lode.
In the middle adit, to the east of the engine shaft, the lode is so wide that
one side only of it has been removed. It is composed of a soft, decomposed,
probably igneous rock (locally called an Elvan), and continues in the same
direction up to the surface.
There is another vein, called Birch's lode, lying to the east near
Stiperstones. It is a kindly well-defined parallel lode. The mine is
situated on the north-west slope of the Stiperstones range, bounded on the
east by Snailbeach, and on the west by Oven Pipe and Pennerly mines.
The strata in which the veins are imbedded is a finely-defined Clay-Slate,
with a large deposit of a rich metalliferous rock. The workings of this
mine were for a time suspended, but have recently been resumed.
Oven Pipe, the adjacent mine, is also rich in lead ore; another equally
rich mine in the same district is Roman Gravels, which is probably the most
ancient lead mine in Britain, having been undoubtedly worked by the
Romans. Through the Middle Ages we have records of its having been
worked at intervals, and of its yielding large profits. It is still active;
and although it cannot be considered one of the best lead mines, it is good,
and may be ranked with West Chiverton in Cornwall and the Lisburne
mines in Wales.
There are many more lead mines in this district than those already
mentioned, but the above are the principal ones. The length of the metal-
liferous district skirting the Stiperstones is about six miles, while that of the
district skirting the Shelve Hill is only about three miles.
The mines working in Shropshire in 1881 were the following:
Roman Gravels, producing lead ore
Snailbeach
""
Tankerville
""
East Roman Gravels
""
Pennerly
Bog
Perkin's Beach
•
2,921 tons.
1,946
542
440 ""
""
25 ""
15
58
""
CHAP. I.]
ALDERLEY EDGE COPPER-BEDS.
257
CHESHIRE.-The New Red Sandstone, or Trias-with the exception of
a strip of Permian-composes the whole county of Cheshire west of the
Red Rock fault. The "pebble beds" consist of liver-coloured quartz with
white quartz, hornstone, and grit. The finest section in these beds is seen on
the banks of the Mersey at Stockport. The Upper Mottled Sandstone has a
thickness of about 600 feet, and rests on the pebble beds. This stratum
may be distinguished by the entire absence of pebbles and the finer grain of
the particles of sand.
The Lower Keuper Sandstone and Waterstones is the massive quartzose
conglomerate which forms the escarpment of Alderley Edge. This
conglomerate is formed of rounded pebbles of white and coloured quartz
very similar to those of the pebble beds of the Bunter Sandstone. In looking
at the Alderley Edge rocks we are strongly reminded of the cliffs of white
conglomerate which form the base of the Keuper series along the valley
of the Churnet, in Staffordshire. At Alton, however, the conglomerate
of the Keuper rests on the pebble beds of the Bunter (Fig. 33), and here on
the Upper Mottled Sandstone, making the contrast. striking. In some places,
at the junction of the Keuper and Bunter divisions, a band of marl
occurs, giving rise to springs. One of these may be seen on the north side
of the Edge, but the same band occurs in much greater strength at the Old
Copper mine on the east of the Edge. The beds which succeed the
Fig. 33.-Cliffs of Conglomerate on Alderley Edge.
conglomerate are formed of white and variegated Sandstone, from which the
copper ore of Alderley Edge was obtained. The same bed occurs in the
escarpment above Clockhouse Wood Farm.
In Mr. Henry Holland's "General View of the Agriculture of Cheshire,'
published by the Board of Agriculture, we find an account of the progress
of mining at Alderley Edge: "This hill forms a striking feature on the
S
258
[BOOK II.
THE FORMATION OF DEPOSITS.
eastern side of the county of Cheshire, rising gradually from the south-east,
and terminating abruptly towards the north by a precipice of 300 or
400 feet in height. A Sandstone rock breaks out in many places on the
summit and northern side of the hill, having an inclination from south-west
to north-east, at an angle of 14 degrees with the horizon. Some of the strata
of this stone are 3 or 4 yards in thickness, and are separated from those
above and below by thin seams of marl, here and there tinged with a slight
colouring of copper. The stone is in great repute for building. Lumps of
marl are, however, sometimes met with even in the most solid blocks, and
still more frequently the rock abounds with pebbles of quartz bedded in it in
all directions. There appear to be three or four great breaks or interruptions
of the Sandstone strata in the structure of the hill. These extend across it
from east to west, and are filled irregularly with Sandstone and masses of
sulphate of barytes, amongst which are many veins of lead and copper, in
some places distinct from each other, in others so mixed as to render it
somewhat difficult to ascertain, from mere observation, which of the two
metals predominates (Fig. 33). Some specimens of very rich lead ore have
been obtained, but on the whole it is poor, and is, as well as the copper, inti-
mately mixed with the grit or Sandstone. Some ore of cobalt has also been
met with. The veins of all these metals approach very near the surface,
and have been found to ramify with increasing richness to a depth of 30 or
40 yards. In all probability they extend much further into the body of
the hill.
"About a century ago Mr. Abbadine, a Shropshire gentleman, cut a
tunnel, 1 yard wide and 5 feet in height, half through the hill, at the
depth of about 30 yards from the highest surface. He met with nothing
but the Sandstone until he arrived at the centre; and finding there that the
valuable part of the ore was considerably below the level of his tunnel,
he abandoned the enterprise. Since that time different companies have
engaged in the same speculation, and have driven tunnels and sunk shafts
into various parts of the hill, but without finding an ore sufficiently pure to
render the mine valuable. One company who undertook it was formed by
Mr. Rowe, of Macclesfield, who was at the head. This gentleman was at
one time very sanguine in his expectations of success, and kept not less than
forty or fifty men constantly employed; but upon the discovery of the great
body of copper ore at the Parys mine, in which he was engaged, he suddenly
gave up his concern at Alderley Edge, and took all his miners with him into
Anglesea."
After this time no search for copper or lead was made in the hill until
some few years since, when, upon the unexpected discovery of a few veins
of good ore at the extremity of the old works, some gentlemen of Stockport
were induced to recommence the speculation. Their prospect of success
appeared good; large quantities both of copper and lead ore were obtained,
and they erected works for preparing and smelting it.
At Mottram St. Andrew, a mile or two to the north-east of Alderley
Edge, in the lands of Lawrence Wright, Esq., both lead and copper ore have
been met with. Intermixed with the Sandstone, which is the matrix of these
ores, some cobalt ore has been found.
CHAP. I.]
COPPER DEPOSITS IN CHESHIRE.
259
"Alderley Edge and its neighbourhood are not the only places in
Cheshire where copper ore has been met with. It has been long known to
exist in the Peckferton Hills, which form the southern part of the tract of
high ground running across the middle of the county. Here it has been
worked irregularly at different times; but from the small quantity obtained,
and its inferior quality, the speculation was not attended with profit to the
proprietors. I understand, however, that a vein has lately been met with
in these hills on the estate of John Egerton, Esq., of Oulton (recently the
property of Sir Malpas de Grey Egerton), from which there was every prospect
of obtaining a considerable quantity of valuable copper ore (Holland).
Smalts was at one time prepared from the cobalt, but eventually the
Excise surcharged the manufacturers for glass duties, and the chemical
works were stopped.
The late Mr. Molyneux, of Burton-on-Trent, discovered a similar deposit
of copper in a mound of Sandstone on Cannock Chase, in Staffordshire.
Similar deposits of cupiferous Sandstone were found at Grinshill, near
Shrewsbury. They were worked first by W. Wright, Esq., and subsequently
by a copper company of Birmingham, who expended a large sum of money
upon the spot, but did no good. With these deposits there was a certain
quantity of the black oxide of cobalt. A similar bed was found at Pims
Hill, as well as other places, but no quantity has been discovered anywhere
but at Alderley Edge. There is silver in some of those strata: a grey
copper ore from one of them gave 320 oz. of silver per ton, but in the
carbonates not more than 1 oz., per unit of copper, has been found.
Galena has also been observed in the strata of the lower Coal Measures
at Whaley. Veins of lead ore have been worked both above and below
the Red Ash mine. The largest quantity of ore has been obtained from
the colliery in the rock below the Red Ash, although the lode itself has
been traced through all the strata down to the Big mine. The position of
this will be seen from the following section:-
Section in Lower Coal Measure, north of Whaley.
Marl (boulder clay)
Shale, with "Flags'
Black shale, with fossils
Coal (Red Ash mine)
Rock (with vein of Galena)
Shale, with fossils
Coal (Smithy mine)
Strata, principally rock
Coal (Cannel mine)
Rock and shale
Woodhead Hill Rock
Shale
Coal (Big mine):
•
•
Ft. in.
60 O
80 0
•
•
ΙΟ O
•
I 6
24
O
36 0
I 6
30 O
I 4
30 O
21 O
3 feet to
39 O
4
The ore was chiefly confined to the rock below the Red Ash mine, in
which the lode was 24 inches wide, and yielded from 60 to 70 lbs. weight per
dish of ore. The lode "perished" in the centre of the basin, but southward
became very rich, and has now been worked out. In the Big mine the lode
occurs as a small fault, and contains small pieces of lead ore.*
"The Geology of Stockport, Macclesfield, Congleton, and Leek." By Edward Hull, F.G.S. and
A. H. Green, F.G.S. ("Memoirs of Geological Survey," 1866.)
S 2
260
[BOOK II.
THE FORMATION OF DEPOSITS.
·
North of Hareshill, resting on the Upper Mottled Sandstone, these deposits
are repeated by a large fault, and also at the copper works at Mottram
St. Andrew. Sections in the same beds occur in the Banks of the Bollin at
Quarry Bank, near Wilmslow, the beds dipping westerly at angles varying
from 15° to 30º.
The following is given by Mr. Edward Hull, of the Geological Survey, as
a summary of the order of succession of the Lower Keuper Sandstone group,
as it occurs in the neighbourhood of Alderley Edge and Wilmslow :—
•
Waterstones-flaggy micaceous brown Sandstones and Shales
Freestones-white and brown, for building
Sandstones-soft white, yellow, or red
Conglomerate-white and reddish
From the same authority we derive the
Thin Sandstone.
SECTION AT THE ALDERLEY EDGE MINES.
Shaly clay-with a band of copper ore at bottom
Ferruginous Sandstone-with nodular masses containing carbonate of lead
Cobalt bed-laminated Sandstone, with cobalt ore
White compact Sandstone-with carbonate of lead
Ferruginous Sandstone-with manganese and cobalt
•
Thickness.
150 feet.
ΙΟΟ
""
•
100
"
•
ΙΟΟ
450 feet.
Ft. in.
4
26
I
6
O
6
•
5
12 Ó
•
It must be remembered that the copper occurs disseminated through the
clay or Sandstone, in a very minute state of division (very small concretionary
masses, like fine shot), as green and blue carbonate, the differences in colour
being determined by the water it contains. The sulphide of lead—galena—
and the carbonate of lead are found in the same disseminated condition.
In the centre of the works a deep hollow cut in the Sandstone occurs.
This is filled with boulder clay, and is 40 feet in depth and 180 feet across
the top. The author visited Alderley Edge accompanied by the late Lord
Stanley of Alderley, and made several sections of different parts of the
workings. This examination rendered it evident that the raised position of
the Edge is owing to the existence of a large fault which runs along the
base of the hill on the north side. Mr. E. Hull, however, remarks: "It is difficult
to understand why the Sandstone rocks of Alderley have been allowed to
remain elevated, while the Sandstone rocks of the contemporaneous beds at
Mottram, Wilmslow, and other places have been denuded down to the level
of the red marl and Bunter Sandstone."
The solution of this problem depends entirely upon the answer which we
give to another. How and when, in geological time, did the bed on
Alderley Edge become impregnated with mineral matters? The beds form-
ing the Edge were deposited at very different times, or they were impreg-
nated with their mineral contents at times clearly separated. The beds are
not sharply marked off from each other, but they pass by a delicate shading
from copper to lead, and from lead to copper.
A careful search leads to the belief that the source from which these
deposits, or one of them, has been derived is close at hand. About the
highest portion of the Edge there is a fissure about 3 feet wide, and it
may be rather more than 30 feet in length. In passing through it, the side
walls were seen to be evidently those of a mineral vein, being-though
CHAP. I.]
FLINTSHIRE LEAD MINES.
261
irregular-quite smooth. This fissure, which had been cleared out, from
the way in which it contracted at the bottom, was, evidently, the thinning
out of a vein. After much careful thought, the conclusion arrived at
was that at a remote period mineral veins of copper, lead, &c., existed
on Alderley Edge, and that the contents of those veins had been removed by
denudation, the metallic matter in solution being filtered, through the sand
beds lying lower down on the hill. The lodes of copper and of the lead may
have been at different levels, and consequently exposed at different times to
the action of water or air (the decomposing agent), so that at one time the
natural filter-beds were receiving solution of copper, at other times solution
of lead, &c.
Lord Stanley of Alderley stated that in some of the ploughed fields
slags were frequently found. On this occasion we had not far to seek,
and many copper slags were discovered. The quantity of copper in those
slags indicated that the smelting operations formerly carried on were of the
rudest kinds. This renders it probable that the veins which formerly existed
on Alderley Edge were worked by some ancient people. By their operations
they laid bare the veins of lead and copper, and this at all events accele-
rated that decomposition to which the deposits in the Sandstone are due.
FLINTSHIRE.-If we suppose a complete cutting through the carbo-
niferous strata which would show the different elements composing it, we
should find in dividing the clays and the Wenlock shales, from the Devonian
Freestone (Old Red Sandstone) on which it rests, the following series:
1. White or Mountain Limestone.
2. Black Limestone, including hydraulic Limestone, known under the name of Aberthaw.
3. Blue Limestone.
4. Chirt or chert.
5. Shale.
6. Gravel.
7. Alterations of shales (schists) and of freestones, Sandstones, "post," &c.
1. The white Limestone is always very clear, and its colour varies from
greyish to pale yellow.
2. The black Limestone, as its name implies, is very deeply coloured, and
often attains a black. It is an argillaceous Limestone, and is frequently
bituminous.
3. The blue Limestone is sometimes found in a hard state and in thin beds,
yellowish or grey-blue, filled with encrinites, sometimes in a state of very
argillaceous schists without consistence, and blue-black in colour.
4. The chert is formed almost exclusively of silica. Its colour varies from
the deepest black to clear grey, sometimes streaked with reddish tints.
5. The shale is a black schist, harder than the blue schists.
6. The gravel consists of rolled pebbles, the dimensions of which are
small, with all the variations between pebbles and sand, the whole more or
less agglomerate and compact, according to the locality.
7. The freestones, &c., are the finely-stratified Sandstones, compact and of
a yellow colour.
Our knowledge of the lead-mining district of Flintshire owes much to the
long and continuous examination made by M. Moissenet, lately Professor of
Mines in the École des Mines in Paris, and in our examination of the filling
262
[BOOK II.
THE FORMATION OF DEPOSITS.
of the mineral veins we shall borrow from his labours. Before we quit this
division of our subject the celebrated well at Holywell, which bears
importantly on the mineralogy of the district through which it flows, must
be described.
The town of Holywell has received its name from this powerful spring,
which is very abundant at all seasons, and which rises with great force at the
foot of a mountain. The volume of water attains 100 cubic metres a minute,
but, contrary to the superstition of the inhabitants, it suffers a considerable
diminution in the summer. This spring is held in great veneration in the
country, especially by Roman Catholics, and is reported to have effected
numerous cures: the proofs of which are suspended in the form of crutches
and other votive offerings in the church constructed over the basin. The
water of the well is hard, and the temperature is nearly always equal.
Thanks to the steepness of the valley, they have been able to form suc-
cessive reservoirs, from the well as far as Greenfield, between which have been
erected several establishments which receive the motive power of the falls
thus created. (A woollen factory, Newton and Keates's lead and copper
works, and a flour-mill, &c., are worked by its water.) It is at these places
that the diminution of the supply in summer is perceived.
The fissure through which this well flows will be seen by the geological
map of Flintshire to commence in the southern part of the large mass of
Carboniferous Limestone near the mouth of the Dee, near Prestatyn. This
Limestone on its eastern edge contains a great number of metalliferous veins
through its entire length. The veins, however, sometimes occur in the
Millstone Grit. On the western side of the Limestone there are but few
mineral lodes, and these occur principally between Diserth and Meliden.
•
DENBIGHSHIRE.-In Denbighshire we find the Mountain Limestone ex-
tending from the Flintshire rocks along the western edge of the Coal-basin to
Llanymynech in the south. With a few very unimportant exceptions, the
mineral lodes are confined to the northern extremity. We find in that locality
a series of very remarkable faults, their general direction being north and
south. One extensive fault, however, running from the west of south to the east
of north, produces a great disturbance between the Limestone and the Millstone
Grit. The Minera lode is the most remarkable, and has been worked more
extensively than any other in the district. This, according to the Geological
Map, extends from the coal-field which it penetrates a distance of between
four and five miles, from the south of east to the north of west. Upon enter-
ing the Limestone on its eastern side a marked deviation occurs, a branch
starting off nearly westerly, and being continued beyond the great fault merely
as a non-metalliferous fissure. The lodes to the south of Minera have the
same general direction, but these are but a few small veins running due east
and west.
CARNARVONSHIRE.-The Great Ormes Head is a mass of Carboniferous
Limestone, in which four lodes occur which all run parallel with each other
north and south. The Limestone beds in some places have a crystalline
character, which appears to claim a relationship with the copper-bearing
veins, for, except when surrounded by a crystalline rock, the veins are
scarcely seen to exist, and are never productive. The crystalline beds and
CHAP. I.]
COPPER MINES IN NANTLLE VALE.
263
the non-crystalline alternate with much regularity, and the metalliferous
character of the veins changes in a striking manner in crossing those beds.
The leading veins are sometimes intersected by cross veins, which are often
favourable to the production of copper ore, especially where the intersection
occurs in a crystalline bed. The ore is then found to extend through the
whole group, constituting a large deposit of copper pyrites.
Sir A. C. Ramsay, who has carefully studied the district of Snowdon, draws
attention to the numerous faults which penetrate the Greenstone and the
Silurian Slates: "Where they most concentrate on the north-west of Glaslyn
several of them-the faults-are copper lodes, one of which, generally striking
to the north-west and branching out in various directions, has been worked
at intervals and yielded a considerable quantity of yellow sulphide of copper."
Copper ore was also found in the neighbourhood of Dolgelly-in Vigra
and Clogau-associated with gold. About half a mile west of Dol-y-Frwynog
the once famous Turf copper mine was situated in the heart of the talcose
schist. Iron pyrites in small crystals is scattered through the rock, together
with specks of yellow sulphide of copper. A peat bog occupied the greater
part of the bottom of the valley. This was found to be impregnated with
sulphate of copper. By burning the peat moss large quantities of copper
were separated.
In the long valley that stretches between Cwm Dyfor and Brynhir bands
of grit appear. These are all overlaid with dark blue Slate; they are much
faulted, the cracks sometimes containing a little copper ore and much iron
pyrites. A little copper pyrites has been occasionally worked near Llyn
Peris, not far from the pass of Llanberis.
Drws-y-Coed copper mine and Symdde Dylluan, in the Vale of
Nantlle, near Carnarvon, occurring in the Silurian Slates, have produced
considerable quantities of copper ore. When these mines were visited some
years since, the author was impressed with an idea that the metalliferous
deposits were not real lodes, but rather, thin beds spread out in the bedways
of the Slate rocks. They are, however, marked as lodes in the Geological
Maps, having a direction from the south of west to the north of east.
In the neighbourhood of Llanrwst, in connection with the intrusive beds
of Felspathic rocks and Quartz Porphyries, numerous lead lodes occur.
They generally have a north and south direction, but two or three of the
lodes run east and west. There does not appear to be any difference in
the metalliferous character of the lodes which can be traced to have any
dependence on their direction.
In describing the rocks of Snowdon, Sir A. C. Ramsay, speaking of the
faults, writes:-
"It is scarcely necessary to enter into all the details of the effects pro-
duced by the faults drawn on the map of other parts of Snowdon. . . . . Where
they most concentrate on the north-west of Glaslyn several of them are
copper lodes, one of which, generally striking to the north-west and
branching out in various directions, has been worked at intervals and
yielded a considerable quantity of the yellow sulphuret of copper (sulphide
of copper)."
After describing many faults, he continues: "Another, which passes
264
[BOOK II.
THE FORMATION OF DEPOSITS.
along the south side of Crib-Goch towards the copper lode, throws the upper
columnar felstone down upon the ashy beds. . . . . A branch of this fault
which cuts through the Greenstone to the south-east is a copper lode, and
has been occasionally worked."
GOLD.-The gold-producing rocks of the Dolgelly district in North
Wales require, from their peculiar character, more than a passing notice.
Mr. A. Dean, who first drew attention to those auriferous deposits, has
favoured us with the following remarks :—
"A line drawn from the junction of the Hirgum brook with the river
Mawddach, to the village of Festiniog would represent the great north and
south anticlinal axis of upheaval and fracture in the district, and the
longitudinal axis of a rough ellipse about 15 miles long by 12 miles wide.
Those limits would enclose nearly all the mines opened in the locality.
Outside, to the eastward and north, other fields are found, the most promising
being the Bala district, in which is situate the Castell Carn Dochan gold
mine.
"Along the longitudinal axis before mentioned, the strata dip from the
centre towards the north and to the south, and fall off also to the east and
the west. The great central boss or dome is occupied by beds of Cambrian
Sandstone and Slate, whilst the lower beds of the Lower Silurian formation
form the surrounding margin.
"In the Lower Silurian beds nearly all the gold mines are opened, but
some quartz veins in the Cambrian Sandstones also produce gold. Great
numbers of floors or beds of Greenstone or ‘Elvan' are enclosed in the beds
of Silurian Clay-Slate, and trap-dykes are of frequent occurrence in the
Cambrian as well as the Silurian beds. Away from the vicinity of the
Greenstone or trap-rocks no good gold lode has been discovered. The
Greenstone beds frequently become so much laminated both at the surface
and in depth as to be scarcely distinguishable from the surrounding
sedimentary beds.
"The whole district is remarkable for the great number of cross courses
and faults which traverse it. Their frequent intersections with the auriferous
quartz veins is advantageous to the latter, as the concentrations of auriferous
minerals are most frequent in contiguity to the cross courses, &c., more
especially upon the dip side of the latter. The auriferous quartz veins have
generally a direction a little south or north of east and west, although gold
has been met with in considerable abundance in veins running nearly north
and south, and at Tyddyngladnis mine a lode bearing north-west and south-
east contains much sulphide of silver, as well as gold associated with lead
ore, blende, &c. This lode traverses Cambrian as well as Silurian rocks.
The Silurian beds traversed by the gold lodes are very various in character;
those which are hard and sharp and well silicified are the best for gold, and
the soft beds are unfavourable to the production of rich auriferous minerals
in the veins.
"When the Clogau St. David's mine became rich in gold a rush for gold-
mining set in, and every quartz vein, without regard to the rocks in which
it was enclosed, was pronounced to be auriferous. This has led to much
disaster, as a great number of workings were commenced in ground which
CHAP. I.
1.]
GOLD MINES NEAR DOLGELLY.
265
offered no chances of success, and would at once have been condemned by
any person really conversant with the peculiarities of the local formations.
The country and gold-mining were so new to the great majority of the persons
charged with the working operations, that great mistakes were inevitable.
Nevertheless, there are good gold mines in the district, and it is to be hoped
that past experience will enable the proprietors to reap the reward of their
enterprise.
"Nearly all the auriferous veins carry lead, copper, blende, and other
ores sparsely disseminated through them, and with those ores the gold is
intermingled through the quartz. Any quartz vein not containing iron
pyrites, blende, or copper ore will generally be found worthless for gold.
During several years numerous attempts were made to work some of the
lodes for the common metalliferous minerals, but in only two or three cases
with success. At that time the existence of gold in the lodes was not even
suspected.
"The presence of so many various minerals has, in many instances,
rendered the extraction of the gold from the quartz a matter of much
difficulty. The improved processes now in course of adoption will probably
overcome the mechanical and chemical obstacles to the desired extraction.
The reduction machinery employed at several mines was wholly unfitted for
the work to be done, even if the ores had been of the most simple kind.
To the novelty of the work to be carried out, to inexperience, and to bad
selection of sites for mines, may be attributed much of the disappointment
and loss which has occurred from first attempts at gold-mining in Wales.
The number of failures in every mining district, whether the mineral
sought be lead, tin, or copper, are probably quite as great in proportion
to the successful enterprises, as those which have occurred in Welsh gold-
mining.
"For the extent of ground wrought, the Clogau St. David gold mine has
probably produced as large an amount of value and profit as any tin, lead, or
copper mine in the kingdom, and there is no reason to believe that other
mines equally rich are not to be found in the district. Indeed, the Clogau
Company are now opening a new mine, which promises to become very
shortly quite as good as the one before mentioned.
"Until lately the discovery of rich bunches of gold was the one object for
which the mines generally were wrought, and no attempt to reduce the poorer
ores was made. The Clogau Company has stamped 2,500 tons of poor ores,
yielding an average of 12 dwts. per ton; and during several months the
Castell Carn Dochan Company stamped 200 tons of the mineral broken
indiscriminately from their lode, with an average of 15 dwts. of gold per ton
of stuff. With good reduction machinery several of the gold mines in the
Dolgelly district might be made to pay."
ANGLESEA.-The following statement of the chief features of the geology
of Anglesea is derived from Sir A. C. Ramsay's work on "The Geology of
North Wales." The long experience of this eminent geologist, and his
habits of close observation, give a value to his description of the rocks of a
country which cannot be improved upon. The Cambrian rocks of Anglesea
were disturbed before the deposition of the Arenig Slates, which lie uncon-
266
[BOOK II.
THE FORMATION OF DEPOSITS.
formably upon them, and which are, it is supposed, overlaid by the Llandeilo
and Caradoc beds.
The Silurian rocks, forming the central part of the island, were metamor-
phosed by the action of a broad tract of imperfect Granite, which crosses
Anglesea from north-east to south-west. Some questions arise in con-
nection with this hypothesis of metamorphism, which certainly require an
interpretation which they have not yet received.
On these rocks the Old Red Sandstone lies quite unconformable, having, in
the absence of the Upper Silurian strata, no passage or direct connection
with the Silurian strata below.
"It seems to me," says Sir A. C. Ramsay, "after long and minute
acquaintance with Wales, that what is now Anglesea and the neighbouring
low-lying parts of Carnarvonshire (and much more besides, now partly
wasted by denudation and partly covered by sea) was a low undulating
country, which by degrees got deeply buried under the Old Red Sandstone,
and Carboniferous strata, so that the whole of what is now the island,
and wide regions beyond, were altogether concealed by these overlying
strata.
“At a later date the Coal Measures and underlying strata were so
far upheaved that the Coal Measures suffered great waste and denudation,
and the Permian strata were deposited unconformably upon them as part of
a wide-spreading salt lake.”
GRANITE, said by Dr. Berger not to be the genuine old Granite, occurs
along the slope of Dun-how, on the road from Laxey to Ramsay.
A similar small Granite is to be seen at Dun-bridge, where it comes to the
surface at 300 or 400 feet above the sea-level. Another small-grained Granite
is found in the Foxdale lead mine, nearly in the middle of the island, 346
feet high.
At 40 yards deep the Granite was found to form the north
"cheek," or side, of the vein, the galena adhering to it. This rock was of a
coarse-grained texture, with reddish and decayed felspar, and plates of
white mica.
CLAY-SLATE is limited to the high ground occupying Snafield (or
Sneifeldt) and other hills. Bishop Wilson determined that the height of
Snafield, “by an exact barometer," was about 580 yards. Slate also occurs
at Mount Pellier as hornstone, and at Peel-hill and Balla-gawn as roofing-
slate.
GRAUWACKE may be traced all along the contour of the island, forming
a range of bold cliffs. Near Laxey there is a grauwacke Slate, used as flags
for flooring houses. Thin coatings of an ash-grey colour spread over the
surface.
LIMESTONE lies conformably over the most superficial of the produced
strata of grauwacke, but the dip became less as the strata retreated farther
back from the land into the sea. It may be comprehended between 10°
and 20°. This secondary Limestone is accompanied by the Magnesian Lime-
stone. These occur in separate beds.
ISLE OF MAN.-Porphyry, Sienite, and other primitive rocks occur in the
island. For the following remarks we are indebted to the late Rev. J. C.
Ward, who was for many years attached to the Geological Survey, and to
✓
CHAP. I.]
ISLE OF MAN AND THE LAKE DISTRICT.
267
this gentleman we are under obligations of no common kind for a most
accurate survey of the Lake District of Cumberland.
This geologist found, in contrasting the physical history of the Isle of
Man with that of the Lake District, that the earliest records of both areas.
are of about the same age, the deposits in both cases indicating a gene-
rally shallow sea, in which muddy and sandy strata were laid down. He
concludes his memoir* in the following words :-
"While this state of things was interrupted in Cumbria by an outburst of
volcanic violence, sub-marine eruptions passing into sub-aerial, we have no
direct evidence to show that such was the case over the present area of the Isle
of Man, though it is probable that some of the finer volcanic ash was at any rate
occasionally wafted for many miles westward. That this area, in common with
that of Cumbria, underwent elevation, accompanied by denudation, in post-
Silurian and pre-Carboniferous times, is at any rate probable, and, as in
Cumbria also, the early-formed Carboniferous strata were deposited around a
Silurian nucleus, the embryo Isle of Man. At this time, off the shores of
that early Mona, submarine volcanic eruptions recurred, synchronous or
approximately so with other like eruptions occurring farther northward
over the present area of Scotland. There is no evidence of any such action
taking place around the shores of the Cumbrian nucleus, although there are,
south of Ullswater, masses of basalt which have broken into the basement
conglomerate, and which may represent-as may also the Shap Granite—
abortive attempts of the volcanic fires towards eating their way to the
surface. Then in both areas we find the long unrepresented periods from
Carboniferous to Glacial times, during which, after elevation at the close of
or soon after the Carboniferous period, the mountain districts of Cumbria and
Mona's Isle were respectively fretted by the denuding forces into their
present form of hill and dale, under climates varying from semi-tropic
warmth to glacial cold. As the cold of our last Glacial period, so called,
reached its maximum, both districts were shrouded in ice-sheets, that of
Cumbria self-born, that of Mona bearing down upon it most likely from a
distance. Then followed a milder time and a submergence to such an
extent that in all probability Cumbria was represented by but a group of
islands and Mona disappeared entirely beneath the waves. As the land in
both areas once more appeared, glacial conditions returned to a considerable
extent, and floating ice laden with stones and boulders played its part in
the cold drama, small bergs and floes being wafted first in one direction,
then in another, as the currents changed with the varying amounts of
elevated land. At length both the hilly areas of Cumbria and Mona stood
up once more as of old, surrounded by a framework of low-lying land con-
necting the two districts, and allowing of the migration of fauna and flora
from what by slight depression soon became the mainland, to the future in-
dependent Island of Man. Thus Mona is like a cast-off bud from Cumbria's
group of rocky mountains."
SCOTLAND.-Leadhills District Rocks.-The excellent observations made.
by the officers of the Geological Survey of Scotland, under the direction of
Professor Archibald Geikie, is adopted here. The geological structure of
*"Notes on the Geology of the Isle of Man." By the Rev. J. Clifton Ward, Ass. R.S.A., F.G.S., &c.
268
[BOOK II.
THE FORMATION OF DEPOSITS.
this district is best seen by taking a section from near Crawfordjohn across
the Snar water, Leadhills, and the Green Lowther, to the valley of the
Potrail water. In this section the Lower Silurian rocks traversed may be
regarded as forming one great synclinal trough, since the lowest strata,
which are seen to the north-west along the great boundary fault, rise again
to the surface on the south-east side along the valley of the Potrail water.
In reality, however, this synclinal trough is folded into several minor syn-
clinal and anticlinal curves, so that the same series of beds is repeated
more than once along the line of section. Two divisions of the Lower Silurian
system are here represented-the Llandeilo and the Caradoc beds. The
Llandeilo series consists of seven well-marked local groups of strata, which,
for the sake of clearness, will be described separately in ascending order.
They consist of the following divisions :-
LLANDEILO Beds.
CARADOC OR BALA BEDS.
g. Black Shale Group.-Grey shales, with bands of fine-grained blue grauwacke
and flinty mudstones, the most characteristic feature being the interpolation of
numerous bands of dark anthracitic shales with graptolites-Estimated
thickness
3,400 ft.
5,000 ft.
J. Lowther Group.-Fine grey shales and finely-laminated felspathic grauwackes,
with occasional grit beds-Estimated thickness
e. Haggis Rock Group, consisting of coarse and fine grits and grauwackes, with
associated bands of red and green flinty mudstone, conglomerate, and occa-
sionally breccia. The most marked feature of the group is the occurrence of
a persistent band of conglomerate containing pebbles of quartz rock, Lydian
stone, and jasper, locally known as the "Haggis Rock"-Estimated thickness 1,800 ft.
d. Dalveen Group.-A series of fine blue and grey grauwackes and shales, having
no marked characteristic to distinguish them from the other members of the
Llandeilo series-Estimated thickness
•
c. Daer Group. A series of hard blue and purplish grauwackes and grey shales—
Thickness not ascertained.
b. Hartfell Shale Group.-Black and grey shales with graptolites-Thickness not
ascertained.
a. Queensbury Grit Group.—Grey and purple gritty grauwacke, with occasional
bands of pebbly grit-Thickness not ascertained.
2,900 ft.
In the high ground round the villages of Wanlockhead and Leadhills, the
Lower Silurian rocks are traversed by two systems of mineral veins, the one
running north-west and south-east, the other west-north-west and east-south-
east. These veins contain lead and other ores. Mineral veins have been
observed in several other parts of the Silurian area, but not of a kind to
offer any prospect of being ever worked for ores. These will be easily
traced on the adjoining map of the Leadhills district, copied from the
Geological Survey Map on the scale of one inch to the mile.
In the country marked by the Spango Granite, as well as the other
Granitic areas, the Silurian strata strike at the Granite on one side, and
reappear on the other, without deflection. The Granite, therefore, whether
we regard it as metamorphic or intrusive, certainly occupies the area once
filled by an equivalent mass of Silurian strata. Wherever a junction of the
Granite and the Silurian rocks is seen, there appears to be a tolerably sharp
line of demarcation between the two, no example of an actual passage from
the foliated schist into the Granite having been met with in any part of the
district. At the same time, it is to be noted that in many places they are
locked into each other, as it were, by numerous veins, which proceed from
the Granite, and run chiefly along the bedding planes of the altered rocks.
Fragments of the stratified rocks are met with in the mass of the Granite, but
CHAP. I.]
LEADHILLS AND WANLOCKHEAD.
269
chiefly along its margin. These are usually angular and oblong, and vary
in size from mere "galls" of a finger-length up to masses ten feet long or
more.
In the area of the Spango Water and the Garepool Burn the Granite is a
fine-grained mixture of pink orthoclase, with a little oligoclase, quartz, black
mica, and hornblende. The quartz, which is second in abundance, is com-
paratively small in quantity, and the black mica is more plentiful than the
hornblende. In the centre of each of these two areas the Granite becomes
€16633
Wanlock wa
1725
1704
WLOCKHEAD
1384
801
41
1780
Clengonner
1683
ALEAD WILES
sh Water
Shortete
N
1793
Fig. 34.-Leadhills and Wanlockhead District.
white in colour and coarser in texture, while the finest-grained varieties are
those which occur in veins. In each district, also, the Granite weathers with
comparative rapidity into a rusty-coloured sand. The waste is greatest
towards the margin of the Granite, where the lower general level of that rock
shows how much more readily it yields to disintegration than the more pro-
minent altered rocks which rise up around it. A white coarser variety of
Granite occurs at the Knipes, the Afton Water near Montraw, and at Cairns-
more. Round each of these areas the phenomena of metamorphism are well
shown, the alteration of the mudstones being specially exhibited round the
Garepool Granitic boss, and that of the schists round the Knipes; in the
latter mass of Granite a vein of antimony-glance has been worked. It is worth
270
[BOOK II.
THE FORMATION OF DEPOSITS.
while observing, that while the Spango and Garepool Granites come to the
surface chiefly in the Haggis Rock group, the Granite in the areas now
referred to is entirely surrounded by the Lowther beds and a small part of
the Black Shale group.
At Leadhills and Wanlockhead galena has long been worked extensively
in the Silurian rocks. The direction of the lodes is, as will be seen on the
accompanying portion of the Map of the Geological Survey, drawn to the
scale of one mile to the inch-generally a little to the west of north—a few
of the smaller lodes taking a north-west course. The heights of the hills
are marked in feet, which will convey a correct idea of the physical
character of the district.
The general character of the lodes may be gathered from the following
description of a part of the Newglencrieff vein, laid open in December, 1868.
The vein here hades to the east at 70° to 75°. Beginning at the last or
"hanger" side, the order of the metals is as under :—
a. Grauwacke, part of the general Silurian rock or country.
b. Zinc blende, black jack, decomposing.
c. Vein stuff, grauwacke ground up and mixed up with quartz
d. Calc spar
e. Galena, sulphide of lead
f. Vein stuff, similar to c, quartzose and passing into pure quartz near
the floor of the level
g. Blue grauwacke; joints veined with calcareous matter
•
h. Hard, fine, compact quartz, with iron pyrites distributed in mass .
k. Galena and barytes, alternating irregularly
7. Vein stuff, similar to c
•
m. Grauwacke (the ledger side of the vein) with slikensides.
I
inch.
inch.
inch to I inch.
inch.
•
2 to 3 inches.
•
3 feet.
7 inches.
8 inches.
4 inches.
The section is about 6 feet high. A string of the sulphide of zinc com-
mences at roof of the level in g, and cuts through all the layers to m; a, g,
and m are the country, and the other layers and the string are properly the
vein. Farther westward a vein of sulphide of lead—galena—was found in the
Silurian rocks to the south of New Cumnock, but it was not sufficiently
remunerative to be continued.
Williams, in his "Natural History of the Mineral Kingdom," remarks of
Leadhills: "They have frequently had remarkably rich lead ore in several
veins, and one of them is said to have been up to 14 feet wide of solid ore
(1789); and 4, 5, or 6 feet of solid ore have been at different times discovered."
I
The following passage, also quoted from this writer, is, on several
accounts, especially deserving of notice: "The most beautiful masses of
lead ore I ever beheld was a few years ago at Leadhills, in Scotland.
was then riding through Leadhills in haste, without the least intention of
stopping, when a singular appearance of a fine bright yellow colour at some
distance attracted my notice. I went up to it, and by some little breaks in
some of the masses I saw it was a rich heap of fine lead ore, lying upon a
shaft head just as it had been drawn out of the works, which ore I viewed
and examined awhile with great pleasure and admiration. The masses of ore
were pretty large, few of them being less than one hundred pounds weight,
and many of them much more; and the outside of every one of these masses
was of the brightest and most beautiful yellow colour I ever beheld, and inside of
each of them was a bright blue, the common colour of lead ore. Upon nearer
inspection, I found this glorious colour to be a rich efflorescence upon most of
CHAP. I.]
LEAD MINES, ISLE OF ISLAY.
271
the meshes; this yellow efflorescence was near an inch deep, of a fibrous,
columnar, and striated texture, the columns shooting out regularly from the
mass all around it, and all of them disposed perpendicularly and parallel to
one another. In short, this was an exceedingly curious and a most beautiful
natural production."
This is curious, as showing how small an amount of mineralogical know-
ledge the writer possessed, notwithstanding his great experience. The
yellow crystallization described by him is well known in Derbyshire, and in
the lead mines of Cornwall, as being the result of very recent changes. The
beautiful "efflorescence," as Williams calls it, is no efflorescence at all. It is
an accumulation of new crystals formed by the exposure of the galena.
A remarkable example of the very recent formation of a mineral ore of
lead, of this description, was discovered a few years since by Mr. John Hunt,
who for many years worked, with considerable profit, the old Roman mine
at Pont-pean, in Normandy.
This gentleman leased from Mr. John Jope Rogers, of Penrose, near
Helstone, the old Wheal Rose mine, near that town, to work above the adit
and over the waste-heaps on the surface. This lease was afterwards extended
to lower levels in the mine. For probably more than twenty or thirty years
the workings of this mine had been suspended. One of the shallower levels,
which had been for this period full of water, was now cleared out. On
removing the water, it was found that the walls of the level were encrusted
with masses of fine yellow crystals of phosphate of lead. This mineral is
found in all the lead-producing districts. In Derbyshire it is called by the
miner, Linetts.
Lead was discovered in the Limestone at Bathgate, where there was
formerly a rich lead mine, yielding a considerable quantity of silver, and
this mineral was found also near Calder.
THE ISLE OF ISLAY.-The mining field of the Isle of Islay, upon the west.
coast of Scotland, is remarkable for the great number of small veins or
strings, some hundreds of which produced, and now contain, some small
quantity of good lead ore, and yet certainly come to nothing at the depth of
a few feet.
The Limestone in which the veins occur is so generally bare that the
mineral veins are readily seen. There are a great many of these running
north and south, and a great many east and west, which cross and intersect
each other at nearly right angles, and there are many oblique or diagonal
veins, which cross and intersect the others at all manner of acute and
obtuse angles. There are also numerous whin-stone dykes of all sizes which
cross and intersect each other and the mineral veins in all directions. Some
of the whin-dykes are not a foot thick, others are 2, 4, or 6 feet thick,
and several extend to from 8 to 12 feet, and some are thicker. Great
numbers of these ribs of stone rise up in ridges above the surface of the
ground, the Limestone being decomposed and washed away around them.
These whin-dykes, Williams says, "are generally a species of that hard stone
which naturalists call basalts, but that they are all mineral veins." He says:
“I am very sensible that most of the miners will startle at this observation,
and will be loth to own that they are mineral veins. However, I expect to
272
[BOOK II.
THE FORMATION OF DEPOSITS.
make it abundantly evident that they were originally the same sort of fissure,
though filled afterwards in whole or in part with matter foreign from what is
called mineral matter." The miners feel that Williams has to prove his
hypothesis. He therefore relates that a late lessee of the mines of Islay
had a rib of solid lead ore for some short time about three feet, and for a
longer time about two feet wide, running parallel to one of those ribs of
stone, in the same vein, and quite close to it, and deeper down in the same
vein he had a considerable wideness of soft mineral soil, with some lead in
it upon the other side of the same rib of stone. The phenomenon described
here is often repeated with the Elvans of Cornwall and with the Toadstone
of Derbyshire.
The number of superficial trials within a space not above ten miles over,
is due, it appears, to the action of some Glasgow merchants who took
a lease, and they employed the peasantry to dig and raise ore at so
much per bing (8 cwt.). These people were allowed to work wherever they
thought proper, and therefore every little string was followed down for two
or three feet, and if not then productive it was abandoned.
The mineral veins of Islay occur in the Limestone, and are immediately
connected with the basaltic rocks or whin-dykes. Williams describes a rib
of solid lead ore, for a short distance about 3 feet and for a longer
distance about 2 feet wide, running parallel to one of those ribs of basaltic
stone and quite close to it, and deeper down in the same vein there was
a considerable wideness of soft mineral soil with some lead ore in it upon
the other side of the same rib of stone.
The principal way of procuring ore in Williams's time was by employing
and encouraging the peasantry of the island to dig and raise ore at so much
per bing. In consequence of the ore being seen on the surface, the country
people laid all the veins open to-day in trenches or ditches where they
found any ore. In some places they did not go down above 2 or 3 feet
in the veins or strings, at most not more than 2 or 3 fathoms, when they
generally came to more water than they could cast out with a dish.
LOSSIEMOUTH.-Williams says of this locality: "There is a singular
stratum of stone near Lossiemouth, in the shire of Moray, of about 8 feet thick,
which is compounded of several species of hard and fine stones of various
beautiful colours. This stratum is a species of breccia or pudding stone, in
the composition of which there is blended in some parts of it about an eighth
part of good blue lead ore of the species called Potter's ore. This curious
bed of stone lies in a horizontal position, and dips away towards the north,
under the sea or Moray Firth, with an easy slope, and the lead is found in
larger and smaller grains and flowers blended through the whole body and
composition of the stone, in the same manner as the small masses of agate,
white and coloured crystals, and other species of stone are found blended
through the whole body of the stratum."
Although the remarks previously made embrace much that relates to the
various conditions of the mineral veins, we must quote a few remarks.
on the phenomena observed in Scotland by Williams,* who gives some
interesting examples of the opening of mineral veins, and mines in pro-
* "The Natural History of the Mineral Kingdom." By John Williams. Edinburgh: 1789.
CHAP. I.]
THE WIDTH OF MINERAL VEINS.
273
gress, and he exposes some erroneous views which have prevailed: "I have
seen a great number of superficial trials in such as carried some ore, but do
not remember ever seeing a thorough trial made in any one of them. A little
hole, 5 or 6 feet down, or a longitudinal slit along the vein, perhaps not
so deep, generally ends the trial. How far this may be right I will not
positively determine; however, it may be proper for me to give my own
observations upon a point of so much importance to the public, as these
veins are very common to be found in all countries where the superficies of
the strata are seen; and in general I have observed that the greatest number
of such veins as are roomy and capacious between the sides at a good
depth—that is, from 10 to 20 fathoms down-are generally very straight, and
close at the superficies of the strata; and besides such as I have seen in
mining fields, I have examined great numbers of them in deep glens or gulphs,
cut or scooped by rivulets in mountainous places, and upon the shores of the
ocean in many parts of Britain, particularly round Caithness and other parts
of the north of Scotland, round a good deal of the coast, and several arms or
inlets of the sea in the Highlands of Scotland and part of Galloway; in all
of which places the rocky cliffs are generally very high and clean, washed by
the dashing of the waves; and it is astonishing what a prodigious number of
the fine mineral veins are to be seen in many places upon those coasts, and
many of them containing some ore and other good mineral symptoms, some
of which I will point out hereafter. At present let it suffice to observe that
the most of the veins which I have seen cut deep down by the water or
otherwise, are narrow or close at the surface, and wider down below. At the
same time it is also proper to observe, that it is very uncertain at what depth
they begin to open. I have seen a great number of fine veins with their sides
perfectly close above, so as to appear at the superficies of the strata no wider
than a common joint, the sides of the vein, perhaps, not an inch asunder,
which, nevertheless, would gradually open downwards, until the cavity or
body of the vein between the sides, at 20 or 30 fathoms down, would be
6 or 8 feet wide, or more; and some of these veins, which are close above
and wide below, begin to open soon, that is, 2 or 3 fathoms below the
surface; others do not begin to open until they are 8 or 10 fathoms down;
and, again, I have seen some which continue so close and straight for a
great way down, that they would not be a foot wide at 20 fathoms below the
surface, which, nevertheless, would open out to several feet wide at a greater
depth.
"These remarks seem to favour straight or narrow veins, and, in my
extensive observations, I do not remember seeing many such as are close or
narrow at the surface which did not open below, if there was an opportunity
of seeing them at a good depth.
"There may be several reasons given for this species of vein being narrow
above and wide below, but these reasons will become obvious to the observing
miner and the intelligent naturalist, when they come to read and consider
the natural history of the phenomena of the strata in general."
After dealing fully with the general conditions of the more important
veins, Williams directs attention to the clay veins, and makes some original
observations thereon:—
T
274
[BOOK II.
THE FORMATION OF DEPOSITS.
"The soft mineral soils are as various in quality and appearance as the
hard. I will point out a few of them in which I will make no choice or
arrangement, but will give them as they occur to my memory. The first I
will take notice of is a white or whitish mineral soil or clay, sometimes
fine, tenacious, and smooth, but often more friable and coarse to the touch,
not unlike slaked lime mixed with small sand. This species of mineral
soil is frequently a promising symptom of lead ore; but I will leave the dis-
cussion of this point until I come to examine the symptoms and appearances
of mines or good mineral veins.
“2nd. Red fatty clay in veins, which indelibly stains the hands and clothes,
is an indication of iron, concerning which I will say nothing just now, but
that the better sort of iron ores are generally accompanied with red staining
softness, by which they are easily distinguished; at the same time, it is proper
to observe that some lead and copper veins contain a considerable quantity
of iron, and consequently of a red or a brownish-red soft soil, and especially
near the surface.
"3rd. Bluish and greenish mineral soils, light and friable, and also
heavy and tenacious.
"4th. Yellowish, ash-coloured, and marbled soft soils or mineral clays,
which are frequently not to be distinguished from surface clays of the same
colours but by the skilful miner.
"5th. Black and blackish-brown soft soils, commonly light and friable,
though there are some of them more tough and weighty.
"6th. The most remarkable and distinguished of all the soft mineral soils,
and frequently the most promising, is of a brown colour, and of a lax and
friable texture, often resembling rappee and other snuff in colour and appear-
ance, being sometimes blackish, but generally brown, in all the degrees
and shades of that colour. . . . . These soft lax soils are called mothers by
the Scotch miners, and where discovered in a vein they are generally reckoned
a good omen for lead and copper."
STRONTIAN.—All the rocks in the mining field of Strontian are a grey
Granite. Several veins in this district were opened by the York Building
Company, and a considerable quantity of lead was raised by them. The
principal vein worked was regarded as having been the strongest mineral
vein in Britain. The York Building Company found a large body of ore at
first cutting quite up to day, which they worked out open-cast, that is,
these works were cut up quite open to the surface, like a large longitudinal
trench or gulf, the vein being exceedingly wide, and they did not mine it
under cover at all.
"The lead ore of Strontian is of the species called Potter's ore, on account
of its being a pure galena, especially useful to the potters" (Williams, 1789).
The geologists engaged on the Geological Survey of Scotland give the
following list of minerals and metallic ores which occur in the Leadhills
and other districts of Scotland.
COPPER.-Copper ore has been found at Currie, on the Lothians, and at
Kissern, in the Highlands of Ross-shire, and trials for working these deposits
have been made in the Limestone quarries. The copper raised was of the
best quality. Copper pyrites is an occasional constituent of the Leadhills
CHAP. I.]
THE MINING DISTRICT OF WICKLOW.
275
and Wanlockhead mineral veins, but it has been worked but rarely. In the
Shetland Isles, at Sandlodge, copper ore has been raised in some quantity.
In 1880, 1,813 tons of ore produced 92 tons 10 cwt. of copper, and in 1881,
232 tons.
In the former year 396 tons of iron ochre were obtained from
the ochre pits, and in the latter year 100 tons.
ANTIMONY.-A rich vein of antimonite, or sulphide of antimony, was
formerly worked on part of the Knipes Granite at a place called Hare Hill,
to the south-east of New Cumnock. The workings have been discontinued,
but many tons of the ore are still to be found near the mouth of the old mine.
Small quantities of antimony are also met with in the mineral veins of the
Leadhills tract.
MANGANESE.—On the old Sanquhar road, about a mile north-east from
Wardlaw Hill, a vein of barytes occurs, containing small quantities of finely-
mammillated pyrolusite. The same Manganese ore is met with also in the
veins of Leadhills and Wanlockhead.
ZINC.-"Black Jack," or sulphide of zinc, is a common constituent with
the galena veins, and occurs sometimes in considerable quantity.
SILVER.-The galena of Wanlockhead is sufficiently argentiferous to
allow of the extraction of the silver with profit.
GOLD.—For more than three centuries gold has been collected in small
quantities from the alluvia of the streams in the Leadhills and Wanlockhead
district, and also in Sutherlandshire.
BARYTES.-The existence of a barytes vein, which is in many places 15
feet thick, may be traced from near the head of Gass Water for two miles in
a north-westerly direction as far as Knockbreck. Another barytes vein,
about 3 feet thick, sometimes containing hæmatite iron ore, occurs on the
flank of Auchensaugh Hill, lying to the east of the Douglas coal-field.
The
IRELAND (Wicklow).—The natural division of the county of Wicklow is,
according to Mr. W. W. Smyth, into an elevated mountain tract of Granite
on the west, and a region mostly composed of Clay-Slate on the east.
boundary-line between the Granite and Slate regions runs from north-north-
east to south-south-west, and within a small width along its western side,
veins of lead ore have been discovered at intervals for a distance of about
thirty miles.
The Granitic veins, varying from an inch to several feet in width, exhibit
a general tendency to follow very nearly the meridian line. A riband
of quartz frequently accompanies them, sometimes at the side and sometimes
in the middle of the vein. The important mining operations which have
been from time to time carried on here will form the subject of further
consideration.
In the cliffs on the side of Comaderry Mountains, in which quartz greatly
predominates, copper pyrites and galena are interspersed. Mr. Weaver
relates that a lump of sulphide of lead, weighing about a ton, was found near
the surface where the veins entered the mica Slate. Among the Granite preci-
pices of Glendalough, about eighty fathoms west of old Luganure vein, a
north and south lode was discovered. This lode carried a rib of decomposed
Granite on its hanging side, and fluor-spar of a green tint. The mines of Ovoca
have for many years yielded at the rate of 100,000 tons of pyrites annually.
T 2
276
[BOOK II.
THE FORMATION OF DEPOSITS.
GOLD.—In 1795, lumps of gold were picked up in a valley on the flanks
of Croghan Kinshela. It was found that the gold occurred disseminated in an
irregular bed of clay, sand, and rounded fragments of rocks, with large
masses of magnetic iron ore. The speculations on this remarkable detrital
deposit have been many, and more frequently led by imagination than
regulated by fact. No opinion of any value can be at present formed on the
origin of these auriferous deposits, but the fact of the occurrence of gold
in the pyrites of Wicklow appears to point to a source from which it might
have been derived.
COPPER.—The mines of copper are in three well-marked groups:
the first group in County Wicklow, occupying the valley of the Ovoca; the
second in County Waterford, around Knockmahon; and the third situated in
the southern portions of Cork and Kerry.
Mr. Weaver, who was for many years the manager of the Wicklow mines,
has described them most accurately, and from his writings many of the
following particulars are gathered. The Clay-Slate district, which corre-
sponds with the Killas of Cornwall, occupies a narrow space not more
than ten miles long, from Croghan Kinshela on the south, to West Acton on
the north. The metallic minerals are extensively diffused in thin layers, in
well-defined veins, and in massive deposits. At various depths in the Clay-
Slate occur beds of "soft ground," which are decomposed slates, varying much
in colour. These beds abound in particles of iron pyrites, arsenical pyrites,
and copper pyrites, and occasionally the sulphide of that metal. Decompo-
sition in this soft ground has gone on to a considerable extent, and the
result has been the formation of alum, copperas, sulphate of iron, and sul-
phate of copper. The drainage waters from these beds is strongly impreg-
nated with copper, which is separated by being run into pits in which scrap
iron has been placed, and thus a large quantity of precipitated copper is
obtained.
Each bed of soft ground contains one or more layers of copper pyrites or
iron pyrites varying in thickness, but sometimes acquiring a breadth of
several fathoms. Five of such beds are met with-one in Connoree, two in
old Cronebane, and one in the new mine, and one in Tigroney. That in
Connoree contains a bed of ore about 4 feet thick, consisting of an inter-
mixture of galena, grey copper ore, blende, and copper and iron pyrites,
sometimes combined with sulphur in much purity, at other times containing
arsenic. At Cronebane the same compound is found in the upper mine, but
in the southern bed the iron pyrites has been very extensively worked, and
grey copper ore has been obtained to the extent of several thousand tons,
passing in depth into copper pyrites (yellow copper ore). The third bed in
this mine has been the most valuable, the bed of solid ore varying from 1
to 3 fathoms in breadth without any intermixture, the more productive
parts of the bed giving from 10 to 15 tons of merchantable ore per cubic
fathom, the average produce being from 5 to 7 per cent. for copper.
Tigroney has yielded large quantities of iron pyrites, the beds, which are in
a firm condition, varying from a few feet to some fathoms in thickness. In
the flinty slate are found several veins of quartz, with rich copper pyrites,
and purple copper ore producing from 10 to 12 per cent. of metal. These
CHAP. I.]
COPPER AND LEAD ORES IN KENMARE.
277
veins range with the Slate, and where they run together they sometimes
form a body 12 feet wide, with 4 or 5 feet of solid ore; but these veins
are seldom more than 30 fathoms in length. The Slate rock is traversed
by numerous smaller veins. The mines of Connoree, Cronebane, and Tigroney
are on the north bank of the Ovoca River. On the southern side are the cele-
brated mines of Ballymurtagh and Ballygahan. These mines are in a
precisely similar strata, and are in all conditions like those already described.
In 1799 the mines of Cronebane yielded 7,533 tons of copper ore, contain-
ing 9 per cent. of copper. In the twelve years ending 1811 the produce was
1,934 tons of copper pyrites, giving 5 per cent. of metal. In 1826 the copper
ore raised at Cronebane was sold at Swansea for £12,354 14s., and that from
Ballymurtagh was sold for £3,373. The Ballymurtagh mine was worked by
the Hibernian Mining Company on a single vein containing copper pyrites.
The vein at 80 fathoms gave 4 tons of dressed ore per fathom of 5 per
cent. produce. The following returns of copper ore sold at Swansea for three
different years are given by Dr. Robert Kane* :—
Ballymurtagh
1836.-Tons.
4,659
1840. Tons.
•
•
3,274
•
Connoree
•
2,158
·
3,017
•
Cronebane and Tigroney
4,691
Ballygahan
305
158
198
1843.-Tons.
1,385
654
1,160
28
It must, however, be remembered that this does not represent the total
produce of these mines. The quantity of ore sold at Swansea-from several
causes-diminished; much was smelted in the neighbourhood of Liverpool;
the poorer ores of Wicklow were sold to large chemical works, and the
sulphur was extracted, the copper saved, and both silver and gold obtained
from the residuary matter after the first processes had been completed.
Copper ore occurs in some of the Slates of the Upper Old Red Sandstone
towards Kenmare Bay. It is nearly always grey copper ore that is found in
the Slates, which decomposing, stains the rocks with the green carbonate
of copper.
Lead ore was worked for some time to the south-west of
Cahirmore.
Specular iron is found in most of the quartz veins associated with the
copper, especially in two veins of quartz on Bear Island, one about half a
mile east of Ardnakinna Point, and the other west of Carrigbreedia.
Both copper ores and lead are found in the Limestone and the Old Red
Sandstone rocks of the Kenmare Valley. One deposit, called Trinity lode,
strikes with the beds of the Old Red Sandstone at Greenlane, about 300 yards
south of the basalt boundary of the Carboniferous Shales. Copper pyrites
appears in the Slates at Cromwell's Fort. Lead ore occurs in the grey Lime-
stone close to the Roman Catholic chapel at Kenmare, but this is probably
only a bed.
The Shanagarry lode contained argentiferous galena, some iron pyrites,
and blende. It is near Shanagarry Castle, north of Cleady Bridge. The
Ardtully copper mine is worked on a true lode, which strikes in a west-north-
west direction across the Limestones, which dip about south 10°, east at 80°,
the lode itself inclining south. It was worked to the depth of 60 fathoms, and
produced grey copper ore, copper pyrites, and purple ore. The lode under-
* "The Industrial Resources of Ireland." By Robert Kane, M.D., F.R.S. 1845.
278
[BOOK II.
THE FORMATION OF DEPOSITS.
lies south 2 feet in 6 for the first 40 fathoms, and then becomes vertical.
Copper in limited quantities has been found at Derreenacahill and Furtane
Lower. Traces of carbonate of copper have been noticed near Caher. The
green carbonate of copper, however, occurs plentifully distributed between
the purple and yellow slates of the Old Red and Yellow Sandstones in the
south of Ireland.
Some years since a large quantity of copper ore was raised on the shore
near the Devil's Island, from the Limestones of Muckroos Demesne. The
lode was subject to much disturbance, and the mineral was consequently
very irregularly distributed. By some this was thought to be a bed, but it
was no doubt a true lode.
Waterford District.-Within a range of three miles from Bonmahon a
number of lodes of lead and copper are observable in the cliffs, some of fair
width, but many very small. The direction of the principal lodes is about 20°
south of east, and the usual dip is towards the north, but there are many con-
siderable deviations. The most productive lodes occur in the Clay-Slate, but
the lodes sometimes pass on into hornstone, in which several ores of cobalt
have been found, but not in large quantity. The lead veins, which have been
rarely worked, are usually charged with galena and calc-spar. The copper
veins consist of quartz, native copper, sulphide of copper, and grey copper
ore, and the black oxide of copper, sulphide of zinc, carbonate of iron, and
sulphate of barytes are also occasionally found.
Captain John Petherick communicated to Dr. R. Kane many impor-
tant particulars respecting Knockmahon mines, which, as manager, he
had ample opportunities of gathering.* From this letter a few especially
interesting notes are gathered. The Slate rock in which the mineral occurs
is of a soft character, and immediately in contact with the productive part of
the lode is softened or partially decomposed. The veins are composed of
compact hard quartz, which is the matrix of the lode, intermixed with
angular fragments of Slate. The principal vein varies in width from 6
inches to upwards of 30 feet, but the average size may be regarded as
about 12 feet, numerous smaller veins occurring on either side. The
mines of this district, which includes Knockmahon, Kilduane, Bonmahon,
and Balinasisla, are worked by the Mining Company of Ireland. The
mining ground leased to this company extends about 4 miles along the
coast and nearly 3 miles inland. The average percentage produce of those
mines is 9 to 10 per cent. The main lode-or rather a portion of the large
vein-is composed of a conglomerate of pebbles of quartz, and copper ore in
soft Clay-Slate. Sometimes the fragments are angular, but frequently they
occur in a rounded state, and occasionally the copper is disseminated in
small particles throughout the mass. This may be regarded as good evidence
of the filling in of the lode from the surface.
The aggregate produce of these mines in the years given was-
1836
1840
1843
•
•
3,588 tons
7,875
•
9, 101
•
£
33,166 value.
63,087
62,950
* "Industrial Resources of Ireland." By Robert Kane, M.D., F.R.S. Second edition. 1845.
CHAP. I.]
THE BEREHAVEN COPPER MINES.
279
Near the Blackwater River, in Tondin Demesne, is a thin-bedded and
flaggy Limestone, containing chert bands dipping to the south at 60°, being
part of the lower Limestone Shale. In this rock, near Camphire House,
nearly a half-century since, a vein of lead and silver was worked.
The Clay-Slate formations in the counties of Cork and Kerry give certain
mineral indications, but the hopes encouraged by these have rarely been
fulfilled, and considerable loss has followed nearly all the adventures.
Allihies or Berchaven mine was discovered about eighty-two years since in
the land of Allihies. In the space of three or four miles there are several veins,
most of which run east and west, and dip towards the north. Two veins
were found to be very productive, and the works have been mainly carried
out on these. One is known as the Mountain mine, which is situated about
450 feet above the sea-level, and is a large east and west lode. The other is
Caminche, which runs north-east. There were, when the mine was about to
be abandoned in 1881, five different veins giving names to as many mines,
called respectively, Keallouge mine, Mountain mine, Caminche mine, Coom
mine, Dooneen mine.
The principal workings in the Mountain mine are about 700 feet in
length, and the mine has been worked to the depth of 249 fathoms below
the adit. The lode is in one place 60 feet wide, but in other places it
diminishes to 3 or 4 feet. At a short distance from the copper veins is a
vein of lead, but it has not been worked. The Caminche mine is worked
for about 570 feet in length and 130 fathoms in depth below the adit. The
Keallogue mine is worked to the depth of 240 fathoms. The vein runs north-
east and dips south-east, the width of it being from 1 foot to 12 feet.
In the Limestones of this district near the townland of Cloghatrida, which
lies to the west of Stoneville, there was a lode containing copper, lead, blende,
and iron pyrites. The lode ran nearly east and west, and underlying to the
north at 70°. The quantity of copper obtained never paid for working. In
the townland of Ballingarrane a lode was discovered bearing north 45° east,
from which a few tons of copper were obtained and also a little calamine.
A short distance from Bantry, at Holyhill, a vein of copper has been
opened; but it was not found profitable, and it has been abandoned.
At Ardtully, near Kenmare, a copper mine has been worked by the Ken-
mare Mining Association. This vein consists of quartz and calc-spar,
containing some copper, and is about 5 feet wide.
At Ross Island, in the Lake of Killarney, is a metallic lode passing
through it, and running parallel to that of Mucruss. The lode dips under the
lake at an angle of 30°. About 200 tons were raised in each month while
this mine was at work. The poorest ore sold at £14 per ton and the richest
at £40. The total value of the copper ore raised in the four years during
which this mine was in operation was £80,000.
The mountains in the north of Tipperary, in which is the gorge of
Killaloe, contain many lodes of lead and copper; but these have not been
found profitable when worked, and they have consequently been abandoned.
At the junction of the Clay-Slate and the Old Red Sandstone the district
known as Silver Mines exists. A split between the Limestone and Clay-
Slate, several fathoms wide at the surface and about 25 fathoms deep, was
280
[BOOK II.
THE FORMATION OF DEPOSITS.
filled in with a decomposing clay, with lumps of the adjoining rocks cemented
by the sulphide of lead, copper, zinc, and iron. The lead was separated,
and from the large quantity of silver which it contained the name of Silver
Mines was given to the spot.
Lackamore mines are in the valley of the Newport River. The lode which
was worked consisted of carbonate of lime and iron, with bunches of rich
copper ore. When Mr. Weaver wrote in 1812, the workings had extended
to the length of 120 fathoms, and to the depth of 30 fathoms. When Dr.
Kane published his "Industrial Resources" in 1845, he says two hundred
men were then employed, "and there were sold in Swansea from this mine,
in 1840, 11 tons of ore, which produced £1,153 7s., and in 1843 200 tons of
ore, which realised £2,386 18s.”
Copper ores have also been found in the Slate district north of Dublin;
at Lough Shinny, near Rush; on the coast at Salterstown, in Louth; at
Brownstown, in Meath; at Tyrone, a few miles from Dungannon. At this
latter place large masses of the grey sulphide of copper have been found in
a vein of conglomerate resting on the Old Red Sandstone, but none of the
attempts made to work at this spot proved commercially profitable.
Lead ore has been found in many parts of Ireland, and is distributed
through a greater variety of rocks than copper ore.
Along the eastern boundary of the Granite district of Dublin and Wicklow
a number of small veins containing lead ore are found; they cross in an
oblique direction the junction of the Granite and mica Slate. Mineral lodes
have been worked for lead at Dalkey, Killiney, or Ballycorus, at Powers-
court, Djoun, Lough Bray, Lough Dan, Glenasane, Glendalough, Glen-
malur, and Shillelagh. With two or three exceptions, none of these trials
have led to any permanent mining operations.
Through the Granite mountains which enclose the lake and ruins of the
Seven Churches numerous veins of quartz exist, and in these are found ores
of lead and occasionally of copper.
At Glenasane a vein of quartz 6 feet wide passes nearly from east to west.
It contains galena, blende, and iron pyrites.
The vein of Luganure runs altogether in Granite. It crosses the Coma-
derry Mountain, and has been traced for near 900 fathoms, and its ascertained
depth is 180 fathoms, and is almost always about 5 feet wide. Mr. Weaver
states that this vein yielded from 3 to 4 tons of galena to the cubic fathom,
giving generally 70 per cent. of lead.
The old Luganure mine, and a neighbouring one, the Hero, have ceased
to yield any produce; but the mine of Ripplagh, on the eastern side of the
glen, and one on the western side, at the base of the Luganure Mountain,
are still termed the Luganure mines. In 1842 these mines gave 675 tons; in
1843, 547 tons; and in 1880 they were yielding to the Mining Company of
Ireland 897 tons 19 cwt., containing 3,360 ounces of silver; and in 1881 they
gave 822 tons of lead, yielding 4,932 ounces of silver.
The Ballycorus lead mine is worked on two veins, which run nearly
parallel, and cross the junction of the Granite and mica Slate. The workings
on these veins generally follow the course of the lode, they sometimes diverge,
and occasionally coalesce. Whenever this is the case valuable bunches of
CHAP. I.]
THE MINING COMPANY OF IRELAND.
281
ore are found. The Mining Company of Ireland, in 1845, discovered a new
vein which contained a lode of native silver. The discoveries made have
not, however, on the whole, been found to be profitable.
At Glenmalure, on the northern side, a powerful metalliferous vein pre-
sents itself. It has been traced about 400 fathoms. Mr. Griffith describes it
as being on the average 15 feet thick, and curiously divided into five parts.
There are 3 feet of a soft slaty substance, with a layer of talc; then a vein of
quartz, from 1 to 3 feet thick-in this lead ore is usually found; then again
2 feet of quartz, in which the largest quantity of lead ore is found; and then
another layer of talcose matter.
On the opposite side of Glenmalure several lead veins have been found.
They have not, however, been found to be of much value.
At Caime, in Wexford, in the Clay-Slate a good quartz vein has been
found bearing galena, carbonate of lead, sulphide of zinc, with pyrites.
Copper ore was sold from this mine, and the Mining Company of Ireland
obtained for a few years from 200 to 500 tons of lead ore, giving 75 per cent.
for metal.
In Louth, Down, and Armagh, lead mines have been opened. At
Armagh, in Derrynoor, one mine gave for several years about 200 tons of
dressed lead ore per annum. At Keady, in the same county, a vein of lead
was discovered and worked for some time. Of this mine Sir Charles Coote,
in his "Survey of Armagh," says: "This mine is on the estate of the college
of Dublin. The lands are held by the Earl of Farnham. The late Earl
expended large sums in sinking and working, but made no profit by it. It
is rather wonderful, and, indeed, proves the value of these mines, that he was
not a considerable loser, as he had no active partner to superintend works
under ground which he never saw himself. The vein is so rich and abundant
it would be well worth the attention of the monied undertaker." There is no
intimation that this mine has ever been reopened.
At Ardenore, in Waterford, and at Ardtully, near Kenmare, lead has been
found, but no profitable workings have been carried forward. In the creek
of Ringabella a lode of lead has been found in the Carboniferous Slate.
Lead has also been discovered in Connemara in the Granite and mica Slate,
and in the same rocks in Donegal. At Kildrum the Mining Company
of Ireland opened a mine for lead, but it did not prove a profitable adventure.
The Limestone formations of central Ireland give evidence of the existence
of lead ore, but the mines have rarely proved productive owing mainly to
the abundance of water, rendering drainage difficult and expensive.
At Clontarf, near Dublin, a lode of lead ore and blende was discovered
and for some time worked. It was on the seashore, and eventually a high
spring tide flooded the mine, and it was abandoned. Numerous veins.
of galena are known to exist in the neighbourhood of Dublin, but none
of them have been found to be continuous to any depth.
At Beaupare and Athboy, in Meath county, and in Kilkenny, lead ore
very rich in silver has been found, but at Floodhall only has any profitable
working been carried on. The Milltown lead mine, in the barony of Tully,
in the county of Clare, is probably one of the oldest lead mines in Ireland.
In 1836 it was worked by Messrs. Anthony Colpoys and George O'Callaghan,
282
[BOOK II.
THE FORMATION OF DEPOSITS.
under the management of the late Mr. John Taylor. The ancient workings
were found to be very extensive, but the modern workings were abandoned
in 1838, after raising forty tons of ore only, which yielded 75 per cent. of
lead and gave 37 ounces of silver to the ton.
Kilbricken mine, in the barony of Bunratty and the parish of Dura,
two and a half miles from Quin, and six miles from Ennis, was opened in
1833. About 25 tons of lead were raised, which gave 76 per cent. for lead and
120 ounces of silver to the ton. The water from the surrounding bogs was
an obstacle to progress. In 1837 a steam-engine was erected.
Ballyhickey mine, in the parish of Clooney and the barony of Bunratty,
is the richest lead mine which has been discovered in the county of Clare.
Operations were commenced on this mine in 1834, and up to 1845 about
2,500 tons of lead ore had been shipped from Clare to the Dee. "The three
deposits of ore above mentioned" (we quote Mr. John Taylor) “occur in
large veins of calcareous spar, which traverse the Limestone rock of this
country. They differ from any hitherto observed in the mining districts of
England and Wales, and indeed upon the continent of Europe. The veins
of spar are of immense width, in places from 20 to 30 feet, and they run
generally a little to the north of east and south of west.
"The quantities of ore found at Milltown and at Kilbricken are so small,
and the masses of spar so large, that it is not easy to trace the inter-
sections of veins or branches at the points of deposit as distinctly as at
Ballyhickey. There the bunch of ore-the richest probably that was ever
seen, taking the number of solid fathoms of ground broken into account and
the tons of ore raised-occurs at the intersection of two veins.
"The main vein runs north-east and south-west, and its tributary falls
in an angle of 45°. At this point the mass of ore was from 16 to 20
feet wide in places almost pure; in others raised with sulphate of copper
and zinc. The total length of the rich branch was about 40 feet, and it
is still orey at the depth of 11 fathoms; how deep it may be worth pursuing
is a question yet to be solved.”
The lead ores of Ireland are all argentiferous, but they vary considerably
in the quantity of silver which they contain. The average produce of silver
extracted from the lead ores worked by the Mining Company of Ireland has
been about 7½ ounces to the ton of lead.
1
The following gives the result of several assays of lead ore for silver
published by Dr. R. Kane, whose chemical accuracy is undoubted :-
From Luganure, Wicklow.
99
Caime, Wexford
""
Ballyhickey, Clare
""
Kilbricken, Clare
Tollyratty, Down
3 ounces.
12
15
120
ΙΟ ""
CHAPTER II.
MECHANICS OF MINERAL LODES, FAULTS, CROSS COURSES, ETC.
PREVIOUSLY to entering on the subject which it is purposed to place before
the reader in the clearest possible light, it is necessary that he should be
familiar with the correct meaning of the terms employed, whether they are
spoken by the working miner-using a provincial term-or by the educated
man who employs terms familiar to him-and probably of archaic origin,
being forms used when the earliest attempts were made in this country to ex-
tend subterranean explorations. Some space will therefore be devoted to an
examination of the terms which will be often met with in our mining districts.
Mine.-A subterranean working in search of some mineral.
"A mine is formed by the penetration of the surface, without exposure
of the works to the light of day, by means of pits, shafts, levels, or tunnels.
It is inaccurate to say that a mine is unopened. The mine is not the
substance, it is only the mode of getting the substance. A vein or stratum
may be unopened, but there can be no mine if there is no opening.'
. .
In the districts where ironstone is raised with the coal, MINE is very
commonly applied to the substance-so much minc-meaning iron ore-is to
be put into the blast furnace. Several writers use the terms vein and lode as
being synonymous, and probably these words have been so frequently used
to express similar conditions, though not the same, that they may really now
be regarded as synonyms. A vein was originally applied to appearances in
the rocks which bore some resemblance to the blood-vessels or veins of the
animal body. These are usually due to injected matter, and they vary in
their names according to the substances of which they are composed, in
the following order :-
Granite Veins in Granite.-These are evidently due to the injection into
pasty Granite of Granitic matter in a fluid or semi-fluid state. These are
commonly spoken of as being contemporaneous, but the vein must assuredly
be newer than the Granite into which it is intruded.
Granite Veins in Slate.-These are really of the same general character
as the preceding, but they have been formed by the action of heat and
mechanical force upon the imperfectly formed Granite mass, the softer
portion, under enormous pressure, being intruded into the still plastic clay,
slowly hardening into Slate. These not unfrequently present a curiously-
branched character.
Elvan Courses, or Dykes.-They are almost always of a Granitic character,
only much finer than the adjoining Granite.
* "Laws of Mines and Minerals." By William Bainbridge.
284
[BOOK II.
THE FORMATION OF DEPOSITS.
Felspar Veins are nearly of the same character-but more or less fel-
spathic. At the Logan rock they are compact felspar, and of a reddish colour.
Mica Veins are generally small, and consist of two layers of mica in thin
plates. These are to be seen at St. Michael's Mount, and in the Granite near
St. Austell.
Schorl Veins.-These are found both in the Granite and Slate, and are
seldom more than an inch wide, though in the Crown rock at Botalļack mine
they are found nearly a foot wide. These are generally short, and they scarcely
fulfil the conditions required by the term vein. They are rather concretionary
masses of tourmaline, or, as the miners call them, "floors of cockle." In Zennor
parish, Schorl rock traverses the Granite veins which appear on that coast.
Quartz Veins are found intersecting the Granite and Slate, and Greenstone
and Limestone. They are of two kinds, one kind being very irregular in size,
direction, and inclination; the other, filling in fissures, partakes of the
nature of a fissure lode.
Steatite Veins are also found in the Serpentine rocks, and they occur in
some places in considerable masses. Agate, jasper, opal, and fluor-spar are
found in veins in the so-called igneous rocks, and in the deposit beds of Slate
and Sandstone. Veins of Asbestos occur in the Serpentine rock of the Lizard,
and sometimes in the Greenstone and Serpentine of Clicker Tor, near Liskeard.
All these veins occur-with the exception of schorl veins—at or near the
junction of dissimilar rocks. They are never metalliferous, although some-
times, especially in Elvans, strings of stanniferous matter are found running
parallel to the vein.
Very different opinions are expressed with regard to the ages of these
veins respectively; but this question remains still a very unsettled one, and
therefore cannot be made in this volume a subject of discussion.
True Lodes, or Mineral Veins.*—These are to be especially distinguished
from the veins already mentioned. Some writers have been induced to use the
term vein without sufficiently indicating the meaning which they desire the
word to convey. "The name lode is given by the miners to every vein which
appears likely to produce metallic substances" (Carne). It is thought, after
the most serious consideration, it will be wise to use the term vein according
to the definition already given, and apply the term lode to fissures or cracks
filled in with metallic ore, and to restrict the distinctive term of mineral vein
to all metal-bearing fissures.
It is not a little curious to trace the origin of the terms applied to the
various conditions prevailing in the rocks which are brought under the eye
of the miner, as in the earlier time especially, in his rude way, he pursued
his exploration. Advancing from the working, illiterate miner, who is
always much of a theorist, we find educated men, who usually draw their
conclusions from observed facts, discussing in a strange way the origin of
the terms used to express the channels in the rocks in which we usually find
the metalliferous minerals. Mr. William Phillips, the mineralogist, in 1800,
is anxious to inform us that he was "at some pains to discover the original
meaning of the term" Lode, or Load.
These are called by Mr. J. Carne true veins, in his paper "On the Relative Age of the Veins
of Cornwall," in the "Transactions of the Royal Geological Society of Cornwall," vol. ii. 1814.
CHAP. II.]
DEFINITION OF TERMS.
285
He refers, he tells us, to Borlase, and he finds the "learned doctor
writing, "From the fissures let us proceed to that which they contain ;
whatever fills them we call a lead," making a distinction between the fissure,
or vein, and the substance it contains. Borlase again says, "Where the
load is barren it may serve to lead to that which is rich;" and in a note he
concludes "the term lode to be an old Anglo-Saxon word meaning lead, thus
loadstone meaning leading stone, and refers to Junius." Phillips says: "I
am induced to believe the term lode, though thus spelt by Borlase and Pryce,
originally meant the burthen or load of the metalliferous vein. Carew,
whose 'Survey' was published almost a century ago, not only so spells.
it, but, in speaking of the effects of the flood on the rocks of the county,
says it carried away so much of the load as was contained therein.'
Besides, it is to be noticed that the north and south veins which are not
metalliferous are uniformly called courses, making a clear technical distinction
between unproductive and metalliferous veins.”
The term vein was evidently applied to the cracks or fissures found in
the Earth's surface through a conceit, of very ancient date, that they bore
some analogy to the venous blood-vessels of animals. Indeed, within the
last half-century a mechanical genius, of considerable and well-earned cele-
brity, told the author that he believed the earth to be a living animal, and the
cracks and lodes so many venous and arterial vessels through which the life
of the animal circulated. The application of the term lode, or load, to these
when filled in with metalliferous matter, is exceedingly uncertain. The
Anglo-Saxons had scarcely any connection with the mines, certainly not
sufficient to warrant the idea that they gave a name to the fissures in which
the metallic minerals were accumulated. Phillips is wrong in supposing
that the term lode was applied only to the east and west veins. The lodes
of St. Just, which are not east and west, and the lead ore veins near the
Tamar, running north and south, are still called lodes. The fissures running
at right angles to the productive lodes are certainly often called cross courses.
But there is a distinction which should be always borne in mind between a
mineral vein and a cross course. A mineral vein is the result of a mechanical
disturbance acting in one direction, and a cross course is due to a disturb-
ance acting at a different period at right angles, or nearly so, to the primary
movement.
It will prove convenient to explain here a term very commonly used by
miners in nearly all parts of the United Kingdom.
The Country.-This name is given to the rocks through which the
miner pursues his search for mineral treasures. All the rocks in a metal-
liferous district are termed "the country." Phillips says: "If a miner be
driving an adit north and south, or in any direction other than that of the
lode, he says he is driving through the country.'" This is not exact. When a
miner follows the lode in its general direction he always speaks of “working
on the lode,” and whether the mineral vein runs east or west, or north and
south, the rocks on either side of it are known as the country.
Mineral veins are sometimes named from the direction which the fissure
takes in the rocks. Dr. Berger observes that the French used to call veins.
pointing east-south-east and west-north-west "filons du matin." The Cornish
286
[BOOK II.
THE FORMATION OF DEPOSITS.
miners, Mr. Carne says, have carried this idea much farther. They call
veins whose direction is due east and west six o'clock veins; and north
and south veins twelve o'clock veins; the veins, therefore, which run fifteen
degrees north of east and south of west are five o'clock veins, and those which
run fifteen degrees north of east and south of west are three o'clock veins,
and those which point south-east and north-west are nine o'clock veins. It
appears that similar modes of describing the direction of veins obtained in
Freyburg. There is, therefore, but little doubt that we adopted these terms
from the German miner. In the north of England a similar custom at one
time generally prevailed. In other cases the names are adopted from the
conditions which prevail in the fissures as they penetrate the rocks, or they
are described according to their contents. These names vary considerably
in different districts, but in the following definition of the miner's terms
an attempt is made to give their generally received meaning.
The mineral veins in the Limestone of Derbyshire are known by several
names, derived principally from their direction, and their dip or underlie.
Rake Veins are seldom truly vertical; they almost always sensibly incline,
or, as it is generally termed, Hade. Sometimes the vein dips at the same
angle throughout, but in some it changes as we descend. A vein first hades
south, then north, then south again; this arises from the character of the
PLATE
CHERT
LIME
STONE
CRIT
RONSTONE
BEDS
LIME
STONE
་་་་
CRIT
Fig. 35.-A Fissure Vein.
rock through which the vein passes.
A crack taking place through a series
of beds-where each bed differs in its
physical condition-will naturally pro-
duce a fissure, altering its hade or dip
in passing through each one of the
beds, as shown in the annexed woodcut,
Fig. 35.
The Rake Veins are said by Farey to
be the most numerous in Derbyshire.
They generally preserve a pretty straight
course on the surface, and they often
run parallel with each other, having
others crossing them almost at right
angles.
The vein underneath a Toadstone bed is seldom of the same width below
it as it is above it, and the parts do not exactly correspond. The vein is then
said to have been squinted, or thrown aside. The rake veins of the miners
are vertical mineral fissures. Williams, in his "Mineral Kingdom," says:
"They are longitudinal gashes, rents, or openings in the rock or strata,
commonly running in straight lines. This gash or fissure cuts all the strata
and rock quite through, from the surface as far down towards the centre as
that vein dips, which is generally out of our reach, and as far forward in the
line of bearing as that vein reaches.
The rock upon both sides of the
vein are called by the miners the hanging side and the ledger side; some
miners call them the hanging side and the hading side, and the longitudinal
line which the fissure points to, is called the bearing of the vein.
"Of these perpendicular fissures or rake veins there are two species. The
CHAP. II.]
DESCRIPTION OF MINERAL VEINS.
287
origin of one of these is a crack or rent and a slip of the strata, and the other
is a gash or chasm in the rock without a slip; the sides of the gash are
separated and opened asunder, but the edges of the strata upon both sides
of the fracture continue opposite to one another, so that there is no slip."
There are numerous varieties of the rake vein which are mainly due to
the inclination from the vertical. These veins vary with the declivity of the
strata, and when parallel and oblique veins have a considerable hade, or slope,
they are called irregular veins. These veins are generally very troublesome
to work on account of their hade and of its irregularity, and the frequency
with which they vary their slope., "Besides the frequent variation of the
slope or hade of these veins, the two sides, or hanger and ledger, of these
veins are also very irregular. The hanging or upper side of them some-
times rises up into a concavity, quite out of the regular flat course of it, and
sometimes again it falls down into a convexity. The ledger or lower side of
these veins are often also irregular, falling into concavities and rising up to
convexities."
The Pipe Vein resembles in some respects a huge irregular cavern
pushing forward into the earth in a sloping direction, but varying con-
siderably in their angle of inclination; they are found indeed in all positions
between the perpendicular and the horizontal. The pipe vein is bounded
by rocks on all sides; in general it does not cut the strata like the rake
veins. Some pipe veins are full of solid ore, others are mixed with spar
and rider. They sometimes open out on the right and left hand to a
great many fathoms wide, and it frequently happens that they rise up into
the roof and sink down into the sole at the same time, so that the pipe
which perhaps was not before much above a fathom high and a couple
of fathoms wide swells out suddenly into a prodigious belly which in bear-
ing pipes proves immensely rich. In Denbighshire, Williams "saw them
working a pipe vein no wider than a good mining-shaft or a coal-pit. This
pipe was almost round, and it was put down in the rock with a slope between
the angle of 45° and the perpendicular. It was quite full of good ore about
6 feet diameter."
The veins in the northern division of Derbyshire run from Castleton
generally south-west, two or three veins only deviating to the north of
west. The great lode from Great Hucklow, after running for some distance
east and west, takes a deviation of about from 10° to 15° north of west. The
lodes to the south of Tideswell generally run north of west, until, in the
High Field and near Taddington, they all run in a south-westerly direc-
tion; this is the case until, after passing Taddington, High Moor, and
advancing to Sheldon, we find at the Magpie mines one lode running east
and west, while a lode from Grey Marble quarry to Monsall has a direc-
tion from south of east to north of west, and one lode at Maddon Vale runs
nearly magnetic north and south. At and around Middleton, and on
Middleton Common, the lodes are within certain limits exceedingly irregular.
At Ladywell Mill the bearing is generally north of west. In the detached
Limestone field of Warslow we have four lodes running north and south,
three have a westerly direction, and two north-west. The lodes at Key-
well Green and High Moor are, two of them north and south, two north-
288
[BOOK II.
THE FORMATION OF DEPOSITS.
west and south-east, one due east and west, and two south of west. In the
centre of the Limestone, a mile south of Witton, we find a group of lodes,
seven of which have a direction north of east, and two south of west. The
lodes on the lower south-western edge of the Limestone are unimportant,
but three of them take a south-westerly direction and two a north-westerly
one. It is not an easy matter to make these conform to any system, and
but little difference has been observed in the produce of the lode, whatever
direction the lodes may take.
The Streek, Flat, or Dilated Vein.-The flat, or dilated vein is a space or
opening between two strata, in like manner as the roof and pavement of a
stratum of coal are above and below that coal. These flat veins are found
between the strata, in several species of stone, but they are most frequently
found in Limestone, lying either in a horizontal or declining position.
Williams remarks some English miners call the flat veins streeks, and when
they have both, a rake vein and a flat vein in the same field, they distinguish
them by the appellation of the vein and the streek. By the word streek they
signify stretch-or a vein between the strata, which spreads or stretches in
a horizontal position. Williams says the flat or strata veins are not fissures
or gashes in the strata, but they are always found between the strata, and are
themselves imperfect strata, or at least each of them occupies the place of a
stratum; so that there is always a very wide difference in the theory of these
two species of veins. The rake vein being always a longitudinal fissure or
break across the strata in some line of direction, in which case the vein is the
chasm, or space between the sides of that longitudinal fracture, whereas
the streek or flat vein is a space between two layers of stone, which space is
generally filled with some mineral matter or other.
The flat vein is not, it must be remembered, the space between two beds
of stone, but the mineral matter which fills that space. As a bed of coal
lies in the Coal Measures, so does a flat vein of lead lie between the beds of
Limestone. These veins have always the same horizontal or inclined
position as the strata has in which they are found, and they are liable to
dislocations, throws, slips, dykes, &c., as is a coal bed. "With this
difference," says a good miner, "that in working the coal these interrup-
tions are generally real troubles, and getting over them is so much pure
loss of money and time; whereas, on the contrary, when they are met with
in working a flat vein they often prove of a great advantage, as they are,
in fact, other mineral veins of different denomination and description, so that
as often as these interruptions are met with in the flat vein it is an adven-
titious increase of the reality, or at least the chance of meeting with more
treasure in the same field." It must, however, be remembered that flat
veins are not necessarily horizontal; nor are they always found between the
strata, having of necessity the same declivity as the beds between which
they lie. The flat veins of Cornwall-for example, those of Carn Brea Hill
—are regular fissure veins dipping but slightly. The carbonas of St. Ives and
Providence mines are another form of flat veins. Sometimes the flat veins.
of Derbyshire will continue of a moderate height between the roof and sole
for a considerable distance, and then the roof and sole will come together,
and open again, after it has travelled a short space. It sometimes happens
CHAP. II.]
VARIOUS KINDS OF MINERAL LODES.
289
that the flat lode or streek opens out into large bellies, although they are more
frequently in flattish glebes or masses, in which case they resemble the
carbonas yet more closely.
Several attempts have been made to describe the way in which the ore is
deposited in these flat veins. The space, or bed, between the layers of rock
may have been subjected to various disturbances, but these must be regarded
as purely accidental. It so happens that a space is left open between the beds
of the same rock-let us say Granite-or between the dissimilar strata of a
newer country; and this space, corresponding to the general dip of the beds
of the district, has been filled in with metalliferous matter of some kind, be
it tin, or lead, or copper, or iron.
Slip Veins are seldom wider above than below; the sides of the fissure are
closer together at the superficies of the strata than at greater depths. These
veins are subject to checks or twitches when the two sides, or hanger and
ledger, come close together, and no cavity or open space is left between them.
Gash Veins, on the contrary, are always wide open above, and grow
narrower in depth, and they often close or check out below altogether.
Williams mentions two remarkable examples of the gash vein, one at
Strontian, in the Highlands of Scotland, and the other at Llangurrig, in
North Wales. Of this last he remarks: "This rich and noble vein was at
once cut out below by a black schistus or shiven, so that no vestige of the
vein was left, nor ever afterwards could be found.”
The swells or wider parts of the vein often remain unfilled, and are fre-
quently found opened; these parts are in Derbyshire known as tick-holes,
jouph-holes, druses, nests, or locks. These cavities are always filled in with the
most perfectly crystallised specimens of the mineral ores. Farey remarks of
the Derbyshire mines: "But in the greater number of cases, particularly where
the tick-holes or empty spaces in the vein were large, a confused and coarse
kind of crystallization, often of a stony texture in part, has completely filled
up these cavities, sometimes without the admixture of any ore, or perfect
spar. These stony masses are called riders, I suppose from the circumstance
of their always resting upon spar (and ore for the most part), and never
touching the vein-skirts or rock in which the vein is formed."
A Kindly Lode is a mineral vein which contains metalliferous ore, and
holds out a promise of its being continuous.
An Unkindly Lode is applied to a vein which contains little or no ore, and
which is regarded by experienced eyes as very unlikely to produce anything
to profit. The Country is also spoken of as kindly or unkindly according to
the peculiar conditions which it presents to the experienced miner's eye.
A Dead Lode is a mineral lode which contains no metalliferous ores. A
living stream or a lively lode was applied by the old miners to productive
deposits or veins.
Flying Veins is a term used by miners to signify a broken, discontinuous,
irregular vein.
Mineral veins are of very varied composition, and they often receive from
the miners names expressive of the peculiarities they exhibit as it regards
their contents.
A Mundicky or a Mundic Lode is one that is filled with iron pyrites,
U
290
[BOOK II.
THE FORMATION OF DEPOSITS.
whether this be a combination of sulphur and iron or of arsenic and iron.
It often happens that a lode bearing mundic near the surface, and at a little
depth begins to show copper pyrites-the yellow copper ore-in depth becomes
a good copper lode.
A Peachy Lode is one containing a considerable proportion of Chlorite.
Such a lode promises more frequently for tin than for copper, although in
many mines-for example, at Polgooth, Relistian, Wheal Unity, and others
-yellow copper ore has been found mixed with Chlorite. Copper ore in
Chlorite was also found in the Wherry mine, in the Mount's Bay, already
described.
Chlorite (from xλwpôs, green, known in Cornwall as peach) is composed of
small pearly, glimmering, scaly particles; it has a somewhat greasy feel, and
bears a resemblance to green earth. It occurs in the tin lodes of Cornwall
and in the mines of Cumberland and Westmoreland. Bristow gives an
analysis of Chlorite from the Pyrenees, by Delesse, as follows:-
Silica
Alumina
Magnesia
Protoxide of Iron
Water
*
32.I
18.5
36.7
0.6
12.I
Chlorite sometimes contains as much as 8 or 9 per cent. of protoxide of
iron. Those kinds which have more protoxide of iron are classed with
Ripidolite, which sometimes gives 28 per cent.
A Flucany Lode, or flukan vein, is one in which the walls or sides on either
one or both sides are lined with a whitish or bluish clayey substance, or
when it is diffused through the lode itself. A flucan is a small fissure filled
in with clay.
A Scovan Lode is when tin ore is mingled with quartz and Chlorite-which
is of a dark brown or of a dirty greenish hue-due, I believe, to the state of
oxidation in which the iron exists. Generally such a lode is not hard or
compact.
A Sucked Stone is a lode which is rarely more than 12 inches wide,
and it occurs sometimes in a mineral vein, the contents of which are not
solid; hence the term: the miner's hypothesis being, that the main lode
has drawn off all the ore from this inferior one.
A Capley Lode consists of hard and unpromising substances, generally
greatly intermixed with minute portions of Chlorite. Tin is often found in a
capley lode, copper rarely. But if a branch of copper ore, or a gossan, be
found to take its course down the vein, it commonly makes a durable mine.
A Pryang Lode (pry is Cornish for clay). When tin or copper ore does not
occur in a compact state, but the stones are found mixed with flucan or
gossan, it is so called.
Black Jack Lode is one that abounds in Blende-sulphide of zinc. It is
considered a favourable indication for copper. "Black Jack rides a good, or
a proud, horse," is a common expression with copper miners.
A Growan Lode (growan signifies gravel in the Cornish language, according
to Borlase). A lode, therefore, filled with fragments of decomposed Granite
is called a growany lode. In the Granitic districts it often happens. But
* Bristow's "Dictionary of Mineralogy." Longman & Co.
CHAP. II.]
TERMS USED IN MINING.
291
growany lodes are productive of copper ore. West Wheal Virgin, Carharack,
and Wheal Damsel, in Gwennap, are cases in point.
A String in mining is a discontinuous vein or mineral fissure, which
extends from the principal vein and starts from it at an acute angle, "and
when it has stretched in that line to an indeterminable though no great
distance, it then terminates in a point, the two sides coming together."
Strings are, in fact, small fissures or cracks extending from the main lode,
and are doubtless the result of the same force which rended the rock; and
as the larger fissure was produced those smaller rents were developed.
These strings fly out from the vein in all directions, but always diagonally.
They are sometimes very rich.
A Bar is a short vein which runs right across, or in a diagonal line
between two parallel veins, joining them as does the bar in the letter H.
A Skew is an irregular mineral fissure starting out from the main lode in
an uncertain direction, generally lying in a slanting irregular position.
A Back is a fissure which often resembles a segment of a circle. "The
back breaks off from the hanging side of a vein, strikes out to a less or
greater distance, fetches a sweep, and comes back into the same vein again
at a distance from where it sets" (Williams).
Guide.—A name given by the miners to iron veins or cross courses, or
rather to veins which are filled, or nearly so, with iron ochre, especially as
these veins are seen in the cliffs on the western coast of Cornwall, yielding
neither tin nor copper. Examples may be seen in St. Just, at Wheal Owls
Point, at Portnanven Cove, and at Caragloss Head.
Trawns, in St. Ives district, are similar to the guides: poor lodes, com-
posed of clay or filled with quartz, are so called.
A Rider.-A vein-stone, which is generally concretionary, found in the
middle of a mineral lode. "This compound stony concretion is called by
miners a rider, perhaps from its riding in the vein, or separating it longitu-
dinally into two or more parts" (Williams). The mineral character of a
rider, which is sometimes called a "horse," may vary considerably. It is
frequently fragments of the enclosing rock cemented together by lime or by
silicious matter. It is sometimes a crystalline formation which has from a
small beginning gradually accumulated into a large mass, and eventually
been surrounded with the metalliferous matter of the vein itself. Williams,
with some reason, says: “I call this vein-stone, as I think the term should
be most intelligible to naturalists, it being always found in veins, upon the
superficies of them, and in fragments and masses lying about upon the face
of the ground, which have slidden or been forced off the superficies of veins."
It is not unusual to find a large body of rider in a large or, as the miners.
term it, a strong vein, standing in the middle of the vein like a wall, with a
space between it and the sides of the vein, dividing the vein in two. These
large masses of rider are frequently very hard. The masses of rider lodged
in the soft matter found in wide, loose veins are sometimes rich in ore; but
usually they contain but little ore, and sometimes none at all. The miners,
when the riders are rich in metalliferous matter, call these masses of ore
mixed with rider;" when they are poor they always speak of "riders mixed
with ore." Such masses are in Scotland and some other places called
U 2
292
[BOOK II.
THE FORMATION OF DEPOSITS.
'glebes," and the soft soil in which these riders are found is called by the
Scotch miners "mother," as schorl (tourmaline) is in some districts of Corn-
wall called the "mother of tin." When a seam of clay occurs between a rider
and the walls or sides of a vein, it is called by the miners a “steeking ;
if it is but a thin vein of clay they call it a "sticking."
·
Bellies of Ore or Matter are large masses, generally isolated, found
either in the vein or in the rock. Strictly, however, the belly is a dilatation
of the vein itself to a great width. Large accumulations of ore in the earth-
caverns in the Limestone have been in the process of time filled in with
metalliferous matter, generally lead. This would be called by the miners a
belly.
"Sometimes the sides of a lode are parallel, and sometimes they recede
from each other, so as to form large accumulations, or, as they are called,
bellies of mineral matter."*
A Waving Vein is a perpendicular fissure which opens and closes
within a short distance. A miner describing it will say it consists of "bellies
and twitches." These twitches, or grips, are contractions in the vein, and
they are generally thought to indicate unproductiveness.
The Accumulated Vein.-Williams, in his "Mineral Kingdom," gives an
important place to this peculiar lode. His description of it, however, goes
to show that it is really only an enlarged pipe vein. He says: "The ac-
cumulated, concentrated, or conical vein is not easily described so as to
convey a distinct idea of it. Some of these veins approach to the form
of vast irregular cones, and others of them have some resemblance to
inverted cones; but, whatever is the form or description of this mineral
repository, it generally contains a great deal of wealth in a small compass of
ground, the accumulated veins being often the richest of all mines.” 'The
main pipe or shaft of the accumulated vein resembles the inside of a glass
house, and the vast capacity of this vein is often stored with a rich body of
metallic ore, frequently bedded with soft mineral soil, but the veins and
branches which join this pipe and diverge from it commonly resemble our
rake veins or perpendicular mineral fissures."
(6
It sometimes happens that a great number of perpendicular fissures meet
and join in one common centre, from which they spread out or radiate to
different distances of the shaft or cone, and these branches frequently contain
rich bodies of ore.
"We see nothing," says Williams, “in the practice of mining so awful
and tremendous as the excavation of large accumulated veins which have
proved rich in ore. The mining shaft or pit for drawing up the ore and for
descending down to the works is frequently, sunk upon the vertex of the
cone or perpendicular pipe; and when you descend 50 or 60 fathoms
down in one of these shafts, you are then swinging in the middle of an
immense void space, where you see on all sides rugged, frightful, hanging
rocks, which threaten to fall upon you and crush you to pieces."
The hade of veins is the mining term, in Alston, for that inclination which
nearly all veins have from a perpendicular direction. Thus a vein is said to
hade to the north when it inclines farther north as it deepens. In Allendale
"Law of Mines and Minerals." By William Bainbridge.
CHAP. II.]
MECHANICS OF MINERAL LODES.
293
and Alston most of the veins hade to the north. In Weardale the veins
generally hade to the south. This hade or inclination is not always uniform.
It varies with the strata, being determined indeed by the character of the rock
through which it passes. Sopwith gives an interesting instance of the import-
ance of attending to the hade of a vein. A freehold estate of thirty or forty
acres was purchased for £1,500. A vein leased from the Dean and Chapter
of Durham ran parallel with, and at a short distance from, one of the boun-
daries of the purchase, but the vein hading into the royalty of the said estate,
the proprietor received from the lessee one-fifth duty, which amounted to
about £800.
The Throw of veins is the usual mining term for that vertical disruption
of the strata which generally occurs near veins of magnitude. There is a
remarkable correspondence between the hade and the throw of veins. The
following rule applied in Alston Moor. "If an east and west vein throws
the strata up on the south side of the vein, then the hade of that vein is to
the north, and the contrary strata are thrown up on the north side, and so of
all other veins." The hade is usually opposite the side on which the strata
are highest on the ledger side of the vein. The variable throw of veins is
illustrated especially in the lead lodes of Alston Moor.
East and West Lodes are distinguished by the direction in which they
lie. An east and west lode is a metalliferous vein whose direction is not
more than 30! from these points.
Contra Lodes are metalliferous veins whose direction is beyond 30°
and not exceeding 60° from east and west. The miners give the name of
a contra lode to every lode which is much out of an east and west direction,
and which crosses the lodes running east and west.
Cross Courses are fissures or veins whose direction is not more than 30°
from north and south.
Cross Flukans are veins of clay having the same direction as the cross
courses.
Slides are thin veins of slimy clay, the result of movements in the rock
or mineral lode, generally greatly inclined, and having commonly an east
and west direction, rarely
running north and south.
Heaved is a term used as
applicable only to a longi-
tudinal shift of the rock or
the lode.
Mr. Carne divides tin lodes
into two classes-the oldest
tin lodes, and the more recent
tin lodes. This division is
founded "on several instances
which have been discovered,
where, at the meeting of two
tin lodes, one of them is
ล
a
3
3
3
α
18
2
Fig. 36.-Heaves at Sealhole Mine.
traversed and heaved by the other. In other words, the great tin lode in the
plan, a b, Fig. 36, had its origin subsequently to the formation of the three
294
[BOOK II.
THE FORMATION OF DEPOSITS.
lodes, 1, 2, 3,—in a disturbance producing the crack or fissure a b, by which
they were broken and moved, the filling in of the more recent tin lode
being effected after the disturbance-the heave-had completed its work.
The tin lode of Wheal Owls in St. Just runs nearly north-west and south-
east, and traverses every other tin lode which it meets. It is generally
stated that the tin lodes which underlie northwards are traversed by those
which underlie towards the south. I conclude, therefore, that the former,
which form a very large majority of the whole, are the oldest." That these
lodes are traversed by other tin lodes, which underlie in an opposite direc-
tion, is evident by examples in Sealhole mine, Wheal Coates, Wheal Owls,
and Wheal Trevaunance.
07
FLAT LODE
COWLING'SL
49 FMS.
SLIDE
54
SLIDE
GO FMS.
LODE
SHAFT
SLIDE
LUDE
LODE
FLAT L
50 FMS.
60 FMS.
CÓWKING'S bar.
Fig. 37.-Dislocations in Penhalls Mine.
A most remarkable example of several of these dislocations, producing a
series of remarkable heaves in the lodes, exist in Penhalls mine in St. Agnes
(Fig. 37). We have evidence of four slides occurring in one direction, and of
a fifth slide in a contrary one. These shift the lodes to a considerable extent,
in each case down to the sixty-fathom level. In several instances there are
heaves acting independently of the slides, throwing the lodes up or down,
and producing the dislocations, which deserve a close study.
Thrown up or Thrown down are terms used to indicate that the lode has
been moved by some disturbance in one direction or the other.
Thyrlings is a term usually employed by colliers,—but it is occasionally
used to express, in the lead mines of Durham and Northumberland and
Derbyshire, a mark indicating the termination of a "sett" or of a "pitch,"
as "A predecessor of the defendant, but with whom he had no privity, com-
mitted a trespass and made holes, called thyrlings, in a barrier of coal
belonging to the plaintiffs, which separated the two collieries."*
Heaves are said to be either right-hand or left-hand heaves. This
signifies that when a lode is dislocated and moved by the interference of
another lode, it may be found on the other side of the traversing lode either
to the right hand or to the left hand. This is thought to be in practice more.
readily understood than the points of the compass.
The more recent tin lodes comprise most of those lodes which underlie
southwards. A few mineral veins in St. Agnes have a southern under-
lie. The valley of Nancherrow in St. Just divides the parish of St. Just in a
* As applied in Coal mining, see "Collieries and Colliers." By John Coke Fowler.
CHAP. II.]
THE HEAVES OF LODES.
295
direction east-south-east to west-north-west. South of this valley all the
lodes underlie north. North of the valley the lodes generally underlie south.
Some deviations from this exist on both sides of the valley.
The ages of the lodes become a very important consideration, and we
are greatly indebted to Mr. Carne for his investigation of this involved
subject. It is to the tribute-miner often a problem of considerable importance
to determine the relative ages of two lodes. Mr. Carne lays it down as a law,
"That a vein which is intersected or traversed by another vein is older than the
vein by which it is traversed." Borlase* had previously speculated on this
being the case, and he quotes Hutchinson's authority for it. Pryce,† in his
work, plainly laid down this rule, and Werner‡ puts great stress upon it.
It will be advantageous to state at once that the following remarks on
the ages of veins are entirely based,-so far as the tin and copper veins are
concerned,—on the paper already alluded to by Mr. Carne.
The oldest tin lodes are indicated by being traversed and heaved by others.
As a general rule, the tin lodes which underlie northwards are traversed by
those which underlie towards the south. Therefore those which underlie
north-and these are the largest number-are the oldest. The more recent tin
lodes comprise most of those which underlie southwards.
In the oldest class of tin lodes must be included most of the lodes in the
tin-producing parishes of St. Agnes and Wendron, and a considerable
number of those in St. Just, and those also in the mines of Wheal Vor, Great
Hewas Down, Wheal Unity, Pedenandrea, Relistian, Trevaskas, Nangiles,
&c.; indeed, the principal lodes in the great tin-producing districts.
The term heaved, as used by the miners to signify a longitudinal
shift of the vein,—and thrown up, or thrown down, to those shifts which take
place on the meeting of two veins, underlying in different directions, in
their downward course, requires some explanation.
It should be understood that this mode of expression, which a stranger to
mining language may mistake for an active movement of the lode, signifies,
only, that there has been a movement of a mass of the Earth's strata, and,
consequently, that a lode which existed as a continuous line, is broken, and
that on one side of the fissure formed, it has been moved either up or down,
as the case may be.
In describing the heaves of lodes, as to the right hand or to the left, it is
meant that when lodes are heaved they may be found on the other side of
the traversing vein by turning either to the right or to the left hand.
Sir Henry de la Beche gives the following very clear definition :
There would appear little doubt that numerous apparent heaves-as the
Cornish miners term these dislocations-are nothing more than contempo-
raneous fractures, with a considerable shift among the various fragments,
both great and small, produced at the same time. The best evidence of
the priority of one set of fissures to another, consists in the general fact that
the body of the country containing the ore is so moved, where traversed
by the other, that the one set merely occupies its general position in
* Borlase's "Natural History of Cornwall," p. 156.
+ Pryce's "Mineralogia Cornubiensis," p. 101.
Werner's "New Theory of the Formation of Veins," p. 51. (Anderson's translation.)
296
[BOOK II.
THE FORMATION OF DEPOSITS.
the country, like any particular beds or masses of rock in following the
general shift, while the other set passes directly through all, cutting across
and destroying the continuity of the contents of the other set, in common
with the general rocks of the country.
1.
e
e
a
S
e m
S
Fig. 38.
1.
ime
Thus, in the annexed woodcut (Fig.
38), which represents a general plan,
on the scale of one inch to a mile,
of part of the Great Cross course a b,
near Redruth, where it traverses the
North Downs, all the lodes or mineral
veins, are moved with the body of
the country, as shown by the heave
of the Elvan courses e e, and of the
junction line of the Granite g with
the Slate ss. In such a case it can
scarcely be doubted that ab is a fissure
formed subsequently to the fissures
marked //.
"A few more words explanatory
of the dislocation of one set of fissures,
by another formed at a subsequent
period, and to the heaves which may be
produced apparently contradictory to each other by the same movement, may
prove of use.
"a b in this section, Fig. 39, represents the surface of a country traversed
ひで
​e-
1
2
α
2
1
Bľ l'é
3/4
Fig. 39.
-b'
5
le
3 X4
b
A
་
2
2
by the Elvan courses e e
and by the lodes .
l
Suppose this country to
be dislocated in a plane
perpendicular to the sec-
tion before us, so that
ab on the one side be
lifted vertically above a b
on the other. It will be
seen that on the level a b,
though the amount of ver-
tical elevation has been
common to all the lodes and Elvan courses, these have, according to their
various dips or underlies, very different relative distances from each other
a.
1'1 12 éi
B
1'31'4 10
ez l's
b.
7, 12
el
A
73 14 ez
Fig. 40.
15
on the one side than on
the other.
"This will be still
further illustrated in a
plan, Fig. 40. While the
lodes 11 12 and the Elvan e¹
are heaved to the right on
the side of the dislocation
marked B, the lodes ³
13
and /* are heaved to the left, and in the latter case a lode, or branch from a
CHAP. II.]
STRATIGRAPHICAL SYSTEMS.
297
lode, l'º appears on the side B which was not on the surface on the side A,
so that three lodes appear on the side B as continuation of the two lodes
visible on the surface at the side A. The Elvan e², which was close to the
lode /* on the side A, is apparently removed far from it on the side B, and,
moreover, contains the lode 15 in the latter case, which was far removed from
it on the side A.”
In connection with these movements it is necessary that the theories of
M. Élie de Beaumont should be understood.* The "Mountain System,”
as he terms it, commences with definitions, and with these we are chiefly
concerned.
Fractures effected in the exterior crust of the Earth have determined the
elevation and uplifting of the rocks of which this crust is composed, and the
crests of these broken and upturned beds of rocks form the summits of those
asperities of the surface of the globe which we call mountain chains.
Links are either straight or made up of straight elements, to which we
may give the name of links. The different "links" observable over a large
extent of country, though presenting great variety of direction, are mostly
connected with a limited number of orientations. Each group of mountain
links, or topographic accidents, characterised by frequent repetitions of these
orientations, is what we call a mountain system.
Relative Age. The parallel links which constitute a mountain system are
contemporaneous. In each mountain range the sedimentary bed may be
divided into two classes. The more recent beds are horizontal right up to
the flanks of the mountains; the others, on the contrary, are upheaved, and
rest upon those flanks, and sometimes are even elevated to form their
crests.
Stratigraphic Systems.-This term includes the great foldings of the Earth's
crust-mountain crests, upheavals, inclinations and plications of the beds,
and fractures of different kinds-which have been produced at the same
epoch under the influence of rectilinear movements acting in a direction
parallel to the direction of a system. Stratigraphy is that part of geology
which is occupied with the geometric description and the graphic repre-
sentative of mineral masses.†
The next subject for consideration is the relation of the throw of veins to
the dip of the strata.
Mr. W. Forster observes that the east and west veins of Weardale generally
throw the north cheek up and hade south; most of those in Allendale and
Alston Moor throw the south cheek up and hade north. In Alston Moor the
dip of the strata is northward, and thus dip, hade, and throw coincide. In the
Swaledale district the dip of the strata across the veins is very inconsiderable
either way, and the throws of the beds are partly north and partly south.
At Grassington the veins range north-west and south-east, and east and
west (the former are the strongest and best veins). They nearly all throw
down to the south, and hade and underlay in the same direction.
In the Greenhow mining field the prevalent directions are west-north-
*"Notice sur les Systèmes de Montagnes." Par L. Élie de Beaumont. 3 vols. 8vo. Paris: 1852.
For a more complete elucidation of the author's views, the English reader should consult the
admirable translation of Professor L. Moissenet's book, "Observations on the Rich Parts of the Lodes of
Cornwall," by J. H. Collins, F.G.S. 1877.
298
[BOOK II.
THE FORMATION OF DEPOSITS.
west and north-west, as at Grassington. The veins go through and cross the
axis of elevation, ranging east by north.
These observations render it apparent that the number of mineral veins
is regulated by the proximity of great lines of fault and anticlinal elevation,
and that their east and west direction is, in the region of the Penine fault,
variable in relation to such. Where the Cross Fell fault ranges north-
north-west it is rectangular to the right-running veins, and parallel to the
cross veins; where it ranges south-south-west it is still rectangular to the
majority of the veins.
Of veins which cross, it has been noticed in the north of the Penine region
that the east and west veins are commonly divided by the north and south
veins, and therefore receive the name of cross courses. Werner has been
almost universally followed in asserting that cross veins are of later origin
than the others, because they cut through them.
Mr. Hopkins very truthfully says: "There is an intimate relation
between the faults, more particularly the longitudinal ones, and those great
fissures in the crust of the globe with which, as mineral veins, we are
acquainted. The veins seldom coincide with the faults, but run near and
parallel to them, clearly showing that whatever cause may have produced
the one class of phenomena must also have produced the other."*
In studying the constitution of rock masses we find not only the bedded
structure, but we have indications, more or less numerous, of divisional planes
traversing the beds at various angles, often nearly approaching the vertical.
In many cases these planes are so thickly manifested and so regularly
produced as to occur in thin laminæ.
"When," says De la Beche, "therefore, we see two series of divisional
planes alike traversing igneous rocks and sedimentary deposits, one series
being either vertical or very highly inclined, the planes varying from a few
inches to several feet apart, and the other series, not so generally common,
having the planes so close as often to divide the rock into thin laminæ, we
are led to suppose that powerful forces, tending to render the mass crystalli-
ferous, have been in action, and that these two kinds of divisional planes are
their effects."
The miner has through all time observed the jointed structure of rocks,
and, as those joints indicate the lines of least resistance, he has made use of
them to facilitate his operations in rending them.
Some joints traverse the rocks without any interruption; some coincide
with the lodes,-some with those of the cross courses, and others with the
direction of the Elvan courses. A little thought will convince any cautious
observer that the relations of one to the other are different. The Elvan
courses are evidently the result of the fusion of Granitic matter which has
been forced by enormous pressure through the rocks. The Elvan may, indeed,
have led to the fissuring of the rocks through which they pierce. Therefore
those joints which coincide with the direction of the Elvans are due to the
mechanical force brought into action by the power of the injected matter.
The joints corresponding with the lodes were no doubt produced by the same
force which caused the fissures in the rocks, which were subsequently filled
* Mr. W. Hopkins, "On the Stratification of the Limestone District of Derbyshire." 1834.
CHAP. II.]
SYMMETRICAL SYSTEM IN ROCKS.
299
in with vein-stuff (the matter forming a true mineral vein). The joints coin-
ciding with the cross courses will have been formed by some similar mechanical
force, acting at nearly right angles to the force producing those which
correspond with the lodes. These joints have long been recognised, but
their coincidence with mineral veins and the fact of their uniformity for
considerable distances have only been pointed out of late years.
*
The joints in rocks are frequently almost indistinct until they are deve-
loped by the influence of slight decomposition, resulting either from the
percolation of water through them, or from atmospheric influences. Mr.
Henwood remarks: "On this account it is often very difficult to determine
which is the principal series; because their exposure to degrading causes in
one direction more than in another will occasion the appearance of one set
of joints in one place, whilst in another a similar cause may operate in a
different direction, and bring out another system of lines. Hence within a
very short distance the principal joints may seem to run at nearly right
angles to each other." He appears in this rather to confound two systems
of joints, the result of forces acting in directions at nearly right angles to
each other.
The jointed structure of different strata is subject to considerable varia-
tion. The Slate rocks are generally divided diagonally into triangular
masses. In Granite the divisions produce more or less cubical blocks.
Sometimes the joints will preserve a tolerable amount of regularity for
some distance, and then exhibit considerable flexures on the lines, both of
direction and dip.
Often the diagonal joints unite with one of the others, and not unfre-
quently one of the rectangular joints swerves from its course and continues
for some time as a diagonal one. Mr. Henwood devoted a large amount
of attention to the examination of rock structures. He thinks there are
two series of divisional planes that are permanent, whilst a third is less
constant. This excellent observer constructed a table giving a general view
of the direction of the joints in the different mining districts. This is so
instructive, and bears so importantly on the formation of mineral veins, that
it is given entire.
DIRECTIONS OF THE JOINTS OR LINES OF SYMMETRICAL STRUCTURE IN
THE ROCKS.
GRANITE.
Districts.
St. Just
St. Ives
Marazion
Gwinnear, &c.
Helston
Camborne, &c.
Redruth, &c. .
St. Agnes.
St. Austell
Tavistock, &c.
N. to 10°
W. of N.
10°—20°
I
2
1 2 2 =
I
H
3
I
40°—50°
50
I
I 3
H
~||~~ |||
2
2
004-009 | m
3
70°—80°
80° W. of
N. to W.
W. to 10°
S. of W.
| | | | | 10°-20°
| 20°-30°
I
I
I
1
I
H
40°—50°
50°-60°
60°-70°
| 70°-80°
80° S. of
H
W. to
* Dr. Berger, Professor Sedgwick, Dr. Boase, Professor Phillips, Mr. Enys, Mr. R. W. Fox,
Mr. Hopkins, and Sir H. de la Beche have each, and all, devoted much attention to the jointed structure
of rocks.
300
[BOOK II.
THE FORMATION OF DEPOSITS.
| 70°-80°
80° S. of
W. to S.
DIRECTIONS OF THE JOINTS OR LINES OF SYMMETRICAL STRUCTURE IN
THE ROCKS—Continued.
SLATE.
Districts.
|| 30°-40°
osob
005-02 | | 13
W.
N. to
of N.
10°
IN
2
I2
223 58 5
2
I
2
I
St. Just
St. Ives
Marazion
•
Gwinnear, &c.
Helston
Camborne, &c.
Redruth, &c.
St. Agnes.
St. Austell
Tavistock
•
3
I
| | | N | | | 50° 60°
I
I
1
| | 60°-70°
I
70°—80°
80° W. of
N. to W.
W. to 10°
S. of W.
6
3
2481OM4N
I
HH
004-009 | |
50°—60°
I
H
2
I
I
2
1 42 ~ ~ MH H
0000 | | I
2
2
2 3
| |~| | |
I
I
I
I
15111
I
2
I
122-
142 5
H
Mr. Henwood furnished a table, relating also to Elvans, but all the
conditions of this intrusive rock are so very different from those of Slate or
Granite, that the direction of the joints are not in any way instructive, and
the observations made have therefore been omitted.
*
When the planes of lamination traverse different beds, interruptions of
the even course of the lamina are often, though not always, observable; they
frequently are bent and undulate. It would appear as if the "laminating
forces" (whatever they may be) had suffered interruption where they encoun-
tered the open spaces between the beds, filled probably with water, contain-
ing, as usual, mineral matter in solution. Professor Sedgwick remarks on
the lamination planes observable in North Devon: "The whole region is
made up of contorted strata; and of the true bedding there is not a shadow
of a doubt. Many parts are of a coarse mechanical structure, but subordi-
nate to them are fine crystalline chloritic slates. But the coarser beds and
the finer, the twisted and the straight, have all been subjected to one change.
Crystalline forces have rearranged whole mountain masses of them, producing
a beautiful crystalline cleavage, passing alike through all the strata. And
again, through all this region, whatever may be the constitution of the rocks,
the planes of cleavage pass on generally without deviation, running in
parallel lines from one end to the other, and inclining at a great angle to a
point only a few degrees west of magnetic north.”
Although the direction of the present magnetic meridian in the district
is temporary, and the tendency of the divisional planes to it is accidental,
yet their prevalence in both igneous and sedimentary rocks leads us to
suppose that electric forces governed the arrangement of the component parts
of rocks, and consequently determined the arrangement of mineral veins.
Dr. Boase, a close and thoughtful observer, remarks that the integrant
particles of rocks are combined and arranged in forms more or less.
geometrical. Their complicated composition may possibly account for their
not presenting the same regularity as perfect crystals, "so that their forms
are not the simple result of the aggregation of similar particles, but the
balance of different powers each tending to produce a different form."† It
* Sedgwick, "On the Structure of Large Mineral Masses" ("Geological Transactions," Second
Series, vol. iii. p. 477). The influence of crystalline forces has not received the attention it deserves.
Professor Sedgwick is the only geologist of note who appears to appreciate its enormous power.
+ Boase's "Treatise on Primary Geology.
""
CHAP. II.]
CRYSTALLINE FORCES.
301
should be remembered that the magnetic meridian is not a constant line, but
one subject to a variation which is very fairly determined. The following
are the magnetic elements for 1882 inferred from observations at the Royal
Observatory at Greenwich:-
Declination (or variation of compass)
Inclination (or dip of the needle)
•
18° 20′ W.
67° 32'*
In 1833 Mr. Enys, of Enys, stated that the vertical divisional planes or
joints of the Granite near Penryn took a general direction from north-north-
west to south-south-east, varying but a few degrees from these points, this
being the most constant direction for the Penryn district. On the northern
part of Dartmoor the Granite was not only cleaved perpendicularly in this
direction, but also on lines at right angles, or nearly so, to it. To show
the average amount of local variation, Sir Henry de la Beche gave several
careful measurements of the divisional planes.
At Peden-maen-du.
Near Carn Cloy
Near Carn Creis
At Nangisal or Mill Bay
At Carn Barra
At Carn Mellyn
At Tol-Peden-Penwith
At West Porth Chapel
At Peden-maen-anmear
·
•
325°
325° to 242°
318°
315°
318°
325°
316° and 218°
320° and 225°
320°
Taking the present magnetic north to be about 335° at the Land's End,
it will be seen that the average of the whole differs by about 13° or 14° from
it. The great divisional planes in the Serpentine of the Lizard approach
very near to the present magnetic meridian. As a whole, the great divisional
planes of the district may be said to prevail more in directions from north to
north-west and from south to south-east than in others, the greatest number
holding their courses within a few degrees of north-north-west and south-
south-east, these lines being cut by others which chiefly form angles from
70° to 80° with them. In addition to these great divisional planes we have
the result of some physical force which has been, by some, referred to
electrical currents, and by others to mechanical force, by which planes of
lamination divide the rock into thin plates.
The crystalline forces referred to above must be considered to be a peculiar
form of a cohesive power, acting with polarity, and thus producing a geo-
metric figure. The author is impressed with a belief that he has shown that
electro-magnetic force has much to do with this symmetrical arrangement.‡
It has been already stated that by long-continued slow electrical action
a schistose structure can be produced in masses of clay, and we shall
presently have to discuss the influence of the same force in producing
* In 1836 the committee of the Royal Cornwall Polytechnic Society determined to furnish the means
by which the true meridian could be accurately determined. The spire of St. Kevern Church on the
south coast was fixed on as the southern extremity of the line, and they erected a granite pillar in a field
to the westward of Beacon Hill to mark its other extremity near Falmouth. This gives a base line of
about 40,000 feet. By this line compasses and other mathematical instruments can be accurately adjusted;
and mine agents and surveyors are enabled to lay down their plans to the true meridian.
"On the Granite District near Penryn, Cornwall,” p. 254. By John S. Enys. London and
Edinburgh. See also "Remarks on the Intensity and Quantity of the Junction Changes of Sussex and
Cornwall," by J. S. Enys (“Philosophical Magazine,” May, 1832).
See "Researches on the Influence of Magnetism and Voltaic Electricity on Crystallization and
other Conditions of Matters." By Robert Hunt. ("Memoirs of the Geological Survey," vol. ii. 1846).
302
[BOOK II.
THE FORMATION OF DEPOSITS.
mineral lodes. De la Beche draws attention to many examples of schistose
structure produced by cleavage lamination, where it coincides with the
great planes of deposit.* It will be right now to consider the bearing
of this on the production of mineral veins. There are constants, relating
especially to the directions of the mineral veins, which should be clearly
understood. These are distinguished as of two well-marked sets, one set
holding an eastern and western course, and the other a northerly or southerly
direction varying from due east and west to 25° south of west and north
of east.
There appears to be considerable probability in the hypothesis that the
richness of a vein in metallic ores is regulated by the direction which it takes
in relation to the magnetic meridian.
A careful examination of the maps of the Geological Survey of the United
Kingdom will prove that the main lines of dislocation extending across the
country indicate the operation of two sets of forces, or waves of disturbance,
one of them producing a series of fissures in the rocks, having a general
direction of north of east, and south of west, and another set operating at
varying angles from these.
The production of true planes is scarcely possible under the varying
conditions, as it regards hardness of the rocks. In the rending of them, by
whatever cause produced, the opening of the fissure will run irregularly,
according as the rock presents harder or softer channels. It is not often
that any fissure presents a perfectly straight line, as it will generally traverse
the rock with more or less irregularity, as if it had been subjected to some
mechanical force acting unequally at different times. The following quota-
tion from the Report on the Geology of Devon and Cornwall is so much to
the point that we quote it in its entirety.
"The walls of a fault or a mineral vein are seldom parallel to each other
for any considerable distance, and could not well be so except in cases where
the fissure has been a mere opening in the containing rock, the relative
position of the sides being otherwise unchanged as regards each other, for it
can scarcely be supposed that the fracture of rocks, particularly when in beds
of unequal hardness, would be such as to produce perfect planes, which if
slid in any direction upon each other would still be parallel. On the
a
a o
a'
C
a
a'
с
Fig. 41.
0
d
C
с
Fig. 42.
Fig. 43.
b
b'
2
contrary, the walls are
generally found to be very
irregular, which must be
the case if two irregular
sides of a fissure were
slid upon each other, no
matter in what direction,
so that they be uneven,
as will be readily seen by
the annexed sketch. Let a b, Fig. 41, be a line of fracture traversing a rock
or rocks, and let a b, Fig. 42, represent the same line; now, if we cut a piece
of paper representing this line, and slide part of the cut paper from a to a',
and from 6 to b', so that the one side be pressed together at the points oo 000,
* "Report on the Geology of Cornwall, Devon," &c. 1839.
CHAP. II.]
ENLARGEMENT OF FISSURE VEINS.
393
we obtain an irregular aperture at d, and isolated cavities at c c c, and when
we compare such figures with nature, we find that, with certain modifications,
they represent the interior of faults and mineral veins. If, instead of sliding
the cut paper to the right hand, we move the lower part towards the left,
about the same distance that it was previously slid to the right, we obtain
considerable variation in the cavities so produced, two long irregular open
spaces cc, Fig. 43, being then formed. This will serve to show to what
slight circumstances considerable variations in the character of an opening
between the unevenly fractured surfaces of a fissure may be due, such surfaces
being moved upon each other so as to have numerous points of contact.
The fractures would of course be more complicated among rocks than those
above sketched, the irregularities of the sides being in all directions, and it
being highly improbable that fragments of the shattered sides, of various
dimensions, were not interposed between them, while others fell forwards
into the fissures, producing a complication of cavities."
In relation to the enlargement of fissures, after they are once formed, it
should be remembered that all fissures, however small, are channels through
which water circulates, that the water contains salts in solution, and that
these crystallise out in obedience to influence of some surface force mani-
fested on each face of the crack. The power of a minute crystal is almost
irresistible, and slowly, silently, but certainly, with enormous force, it presses
the sides asunder, and by enlarging the fissure gives space for the exertion
of a still greater force. Those who desire to deal more especially with the
filling of mineral veins will find this force will especially claim their attention.
The direction of many lodes in the vicinity of Tavistock and Callington is
upon points which do not vary considerably from east and west; those
which differ from that line being probably the Crowndale and Gunnis-
lake lodes, and the Wheal Franco lode, near Horrabridge. Wheal Friend-
ship lode differs but a few degrees from east and west; this is also the case
with Wheal Jewell tin lode. The lodes on Plaster Down, near Monk's Hill,
at Wheal Robert on Roborough Down, Morwell Down, on the banks of the
Tamar, above New Bridge, at Holmbush, at Wheal St. Vincent, Wheal
Brothers, and at several of the mines around Callington, differ only a few
degrees from east and west. On Dartmoor, some two lodes near Oke-
hampton, on both sides of Longstone Hill, appear to take course about
west 30° south and east 30° north. Between Belstone and Okehampton
the lodes are generally east and west. The Bottle Hill lodes near Plympton
vary but little from east and west.
At the Beer Alston mines are two great lead lodes, very argentiferous in
character, which are north and south lodes. These may indeed be con-
sidered as cross courses, and they take directions which would cut the
Drake's Wall and adjacent lodes. The north-north-east and south-south-west
lead lode at Redmore Mine, near Callington, is another instance of cross
courses bearing lead ore in this district.
Similar conditions are preserved generally in the St. Austell district.
The main lodes in the Fowey Consols mines approximate a true east and
west direction; but there are minor lodes which run more west-north-west
and east-south-east, which direction obtains in the Charlestown, Pembroke,
304
[BOOK II.
THE FORMATION OF DEPOSITS.
and the Crinnis mines. The great mass of mineral veins in the Gwennap,
Redruth, and Camborne districts may be regarded as a portion of the same
system. It is evident that the west-south-west and east-north-east direction
is continued from Camborne, through the parish of Gwinnear and Wheal
Alfred: the Herland mine, and the lodes of Relistian preserve this direction,
as do also the lodes at Wheal Trenwith and St. Ives Consols. Proceeding
along the coast from St. Ives to Morvah, nearly all the lodes coincide with
the same direction, and those of Ding Dong tin mine in Gulval generally
take the same course.
In the St. Just district the lodes have a main direction from the north
of west to the south of east, and a remarkable change is observed in the
character of the copper ore raised; the St. Just mines yielding, as a rule,
the grey sulphide of copper.
Length of Veins.-Lodes vary very considerably in length; in some
cases they are only a few fathoms long, and they have been known to
extend for two or three miles, several mines being worked on the same lode.
"It ought to be noticed that the most experienced miner never satisfactorily
witnessed the termination of a vein either on the east or west" (Phillips). This
is, in many instances, doubtless true, but it cannot be admitted to be so in all
cases. This authority has given a plan of the Herland mines and of Prince
George mine. In these we find the following are the lengths represented:
Prince George vein
Prince George south vein
South Branch vein in Herland
Middle Branch vein in Herland
175 fathoms.
225
250
225
""
"
the main lodes in these mines traversing the rocks to a far greater length.
He remarks that "the veins of those mines did not terminate as represented
on the plan, but continued both east and west to an unknown extent, in
strings so very small as only to be just perceptible."
Mineral lodes are supposed to extend frequently to considerable dis-
tances; but the observations made have from various causes been too
general, and too imperfect to be of any real value. Those which are laid down
on the maps of the Geological Survey may be regarded as the most reliable,
and from those maps the following examples have been selected. First, in
the St. Agnes District, the distances have been well established.
At Wheal Kitty, lodes are traced from Trevellas to the coast at Tubby's
Point, about 3 miles.
The Polbrean lode extends from Dirty-Pool, in the centre of the parish,
to Chapel Porth, about 2 miles.
Wheal Butson is traced from that mine through North Towan and United
Hills, about 4 miles.
In Breage, near Helston, the Wheal Vor lode is rather more than 1 mile.
The actual length of the workings is 1,150 fathoms, and the lode has been
traced beyond them.
In the important Gwennap mining district-
North Downs is traced on the Geological Survey Map about 3 miles.
Wheal Busy
Treleigh mine
Poldice
""
""
""
››
""
21/10
2
""
2/13/1
>>
""
CHAP. II.]
LENGTH OF MINERAL LODES.
305
United mines, from Chicasse to Ting Tang and the Carn Marth Granite,
4 miles.
In the Redruth and Camborne district :
From Wheal Fortune to North Roskeare the lode has been traced 1½ mile.
Cook's Kitchen, from Burncoose to Camborne, 2 miles.
Dolcoath-which probably is the same lode as is worked in the mines on
the north edge of Carn Brea-about 3 miles.
North Roskeare and other mines show distances varying from mile to
2 miles.
In the district of Liskeard, the South Caradon lode has been worked for
1½ mile, and Trevenen mine, irregularly, for about 24 miles.
By far the largest number of tin and copper lodes are under a mile in
length, as will be seen by reference to the map of mineral veins and cross
courses in the Camborne and Illogan district.
The following statement of the lengths to which mineral veins have been
traced is given on the authority of Mr. Carne * :-
The old lode in the United mines has been traced from Camborne,
through Carn-Kye, to Baldue, a distance of 7 miles. (It appears to the
author very questionable if this is a continuous fissure. The ground has
been walked over, and there are probable evidences that three lodes follow
closely upon each other in very nearly the same direction.)
Wheal Fortune and Wheal Virgin lode has been seen for almost 3
miles in length. Wheal Damsel and Wheal Maid lode, 2 miles. Wheal
Gorland, Wheal Unity, and Creegbraus lode, 2 miles.
Wheal Nancy, Camborne Vean, Wheal Stray-park, Dolcoath, and Cook's
Kitchen, 3 miles. Mr. Carne adds in a note to this: "This lode is so disordered
by cross courses at Cook's Kitchen as not to be accurately traced eastwards.
Many miners, however, consider it as the same lode that passes through
Wheals Fanny, Druid, and Wheal Sparnon, from whence its course is
through Carn Marth Hill to Wheal Damsel, Carharach, and Wheal Maid.
This would be nearly 6 miles." The continuity of the same mineral vein
is, however, exceedingly problematical.
Wheal Towan has been traced for 1 mile. Binner Downs, Whcal Sarah,
Wheal Abraham, Oatfield, Crenver, and Trenoweth, 2 miles. West Wheal
Fortune, Kestal, and Penberthy Crofts, 3 miles. The Old Wheal Alfred lode
is said to extend 1 mile; but several workings stretch westward, which may
be upon portions of the same lode.
None of the tin lodes have been followed more than two miles in length,
and those of Wheals Peevor and Poldice are the only ones which have been
traced to so great a distance.
It will be seen from this, that the length of the fissures which have been
formed, by some great movement of the superficial strata of the Earth's crust,
is very variable. If we reflect on the causes which produce those cracks, we
can well understand that this would be the case. We have great cross
courses and faults extending across large tracts of country but with these
* "On the Relative Age of the Veins of Cornwall." By Joseph Carne. (“Transactions of the
Geological Society of Cornwall," vol. ii. 1822.)
X
306
[BOOK II.
THE FORMATION OF DEPOSITS.
we are not dealing, but with the smaller systems of fissures which belong
especially to the series of true mineral veins.
Having considered the evidences which we possess, and which give some
idea of the lengths to which mineral veins may be expected to be prolonged,
we have to consider the direction in which those lodes traverse, which has,
according to many excellent observers, an important bearing on the mineral
character of the veins. Then we have to examine the dip or inclina-
tion of those ore-fissures, which is very various, and the connection of these
phenomena with the bearing character of the lode.
Mr. Henwood, in his prolonged Mineralogical survey-extending over
S DIP
a
N DIP
Ъ
a
SOUTH
Fig. 44.
Fig. 45.
several years-made observations in the most important of the mines in
the West of England, accumulating a large series of facts of the utmost
CRIAN
TE
5, 1771000
Fig. 46.
MARTI
VEIN
EIN COPPER
NEW >
7.
COPPE
value, and which are unique of their
kind. The annexed list has been derived
entirely from this source.*
Underlie of the Lode.-Mineral veins
are seldom perfectly perpendicular; they
usually incline more or less to the north
or south; this inclination is called the
underlie of the lode.
When two metalliferous veins under-
lie in opposite directions, one inclining
or having what is called the dip to the
north, and the other south, as in Fig. 44,
they are generally found to be poor at
the junction a, and after it at b.
in Fig. 45, they mutually enrich each other.
*
When two lodes underlie in the same
direction, but that one, a, of them dips
more rapidly than the other, b, it is gene-
rally found that, when a overtakes b, as
Veins are sometimes found to divide in the downward direction, and so
"On the Metalliferous Deposits of Cornwall and Devonshire." By William Jory Henwood,
F.R.S. ("Transactions of the Royal Geological Society of Cornwall,” vol. v.)
CHAP. II.]
DIRECTION AND DIP OF MINERAL LODES.
307
make branches forming distinct lodes, having an opposite underlie, as in the
annexed example, a section in Tin Croft mine (Fig. 46).
DIRECTION AND DIP OF LODES.
Name of Mine.
Name of Lode.
ST. JUST.
Direction.
Park-Noweth
Botallack.
Wheal Cook
Levant
Wheal Sparnon.
Boscaswell
Balleswidden
•
Capt. Ben. Davy's 30° N. of W.
•
Crowns
Tolven
Main Lode
Wheal Shop
Great Work
Main Lode
""
Dip.
Wheal Bellon
""
Cunning
Edward.
Wheal Whidden
Main Lode
•
•
""
""
43° N. of W.
35° W. of N.
35° W. of N.
N.E. 83°
N.E. 73°
N.E. 80°
S.W. 67°
•
20° W. of N.
24° W. of N.
18° W. of N.
20° W. of N.
33° W. of N.
24° W. of N.
30° N. of W.
MADRON, SAINT IVES,
GULVAL, LELANt.
Ding Dong
""
Bossiliack
•
•
30° S. of W.
United Mines
Wheal Union
Wheal Tren with
Wheal Reeth
St. Ives Consols
Lelant Consols .
Providence
Main Lode
Bussa Trawn
Main Lode
33° W. of N.
•
35° W. of S.
North Course
40° W. of N.
N.W. 60°
Gwen's Lode
15º S. of W.
S. 86°
23° S. of W.
S. 68°
North Lode
24° S. of W.
N. 70°
Standard Lode
25° S. of W.
N. 78°
Main Lode.
•
40' S. of W.
40° S. of W.
S.E. 66°
E. 74°
S.W. 68°
E. 78°
W. 83°
S.W. 74°
E. 84°
S. 60° to 80°
Principal Contents of Lode.
Quartz, oxide of tin.
Pink felspar, oxide of tin.
Iron ore, copper.
Quartz, iron, oxide of tin.
Iron ore, quartz, copper, tin.
Pyrites, copper.
Quartz, iron ore, copper.
Iron, quartz, copper.
Quartz, iron, tin.
Quartz, iron, oxide of tin.
| Felspar, quartz, oxide of tin.
S. 72° to 80° | Split into branches, schorl and
W. 52°
N.W. 70°
N.W. 78°
oxide of tin.
Iron ore, oxide of tin.
Quartz, schorl, tin.
Quartz, oxide of tin.
""
Iron, vitreous and black copper.
Granite and oxide of tin.
Iron pyrites, oxide of tin.
Felspar, oxide of tin.
Copper and tin.
MARAZION, GWINNEAR, &c
Wheal Darlington
Gwallon
Rosepeath
Great Wheal Fortune
Retallack
Godolphin West
Herland
Relistian.
Binner Downs
West Mine.
20° N. of W.
S.W. 54°
Quartz, copper, tin.
•
South Lode
Main Lode.
5° S. of W.
S. 72°
5° S. of W.
N. 78°
E. and W.
S. 64°
""
""
22° S. of W.
N. 68°
""
""
25° S. of W.
S. 59°
Quartz, oxide of copper and tin.
Iron and copper pyrites.
Quartz, copper pyrites.
Iron ore, copper.
""
North Herland
North Lode.
20° S. of W.
S. 72°
20° S. of W.
N. 64°
Iron, quartz, copper pyrites.
Iron, copper pyrites.
•
Gooseberry .
25° N. of W.
S. 70°
""
Wheal Strawberry .
Carside
25° N. of W.
S. 79°
Carside Lode
•
9° S. of W.
S. 70°
Oxide, tin, copper.
HELSTONE, BREAGE,
WENdron.
Great Work .
Wheal Vor
Polladras.
Trumpet.
Stray Park
Dolcoath.
""
•
Wheal Breage.
Main Lode
Wheal Wreath.
Engine Lode
30° W. of S.
W. 68°
Quartz, oxide of tin.
28° S. of W.
N. 65°
Iron pyrites, tin.
•
28° S. of W.
N. 74°
•
35° S. of W.
N. 64°
Quartz and oxide of tin.
Wheal Ann Lode
22° S. of W.
N. 78°
Iron ore, oxide of tin.
•
CAMBORNE AND ILLOGAN.
North Lode
Entral
Harriet's Lode.
Caunter.
•
N.E. and S.W.
30° S. of W.
N.E. and S.W.
11° N. of W.
S.E. 78°
Quartz, iron, copper pyrites.
N. 64°
S. 70°
Cook's Kitchen
South Lode.
22° S. of W.
S. 65°
Dunkin's Lode
34° S. of W.
S. 60°
Carn Brea
•
Teague's
28° S. of W.
N. 78°
North Lode
30° S. of W.
N. 70°
South Roskear
North Roskear
Wheal Crofty
East Crofty
East Pool
"}
•
•
Main Lode
•
32° S. of W.
S. 80°
N. Roskear Lode.
32° S. of W.
N. 77°
North Lode
5° S. of W.
N. 73°
Longclose
South Lode
North Lode.
15° S. of W.
25° S. of W.
40' S. of W.
N. 80°
S. 70'
N. 68'
""
S.E. 70°
Copper, galena, silver.
Quartz, copper pyrites.
""
Quartz, copper, tin.
Iron ore
""
Copper ore, tin.
"
Iron and copper pyrites.
Copper and iron pyrites.
""
Quartz, copper pyrites.
""
Copper and iron pyrites.
X 2
308
[BOOK II:
THE FORMATION OF DEPOSITS.
REDRUTH AND GWENNAP.
Name of Mine.
Name of Lode.
Direction.
Dip.
•
•
Wheal Buller
Tresavean
Ting Tang
United Mines
""
""
Consolidated Mines
Damsel' East
Cardrew
North Downs
Buzza or Mundic .
Taylor's Lode.
Deebles
•
South Lode
Main Lode
25° S. of W.
30° S. of W.
N. 64°
S. 78° and 84°
12° S. of W.
N. 70°
وو
""
Old Lode
27° S. of W.
N. 60°
25° S. of W.
N. 70°
27° S. of W.
N. 76°
30° S. of W.
N. 70°
North Lode
17° S. of W.
N. 72°
South Lode
17° S. of W.
N. 60°
John's
21° S. of W.
N. 72°
Principal Contents of Lode.
Iron and copper pyrites.
Iron, copper pyrites.
""
Quartz and copper pyrites.
""
""
Copper pyrites and black.
""
""
Iron and copper pyrites.
Iron ore and pyrites.
""
Main Lode.
14° S. of W.
S. 82°
Iron, copper, blende.
""
""
ST. AGNES AND PERRANZABULA.
Charlotte East
Main Lode
12° S. of W.
S. 64°
Iron, black copper.
•
•
Polbwroe
Pink West
Pye Lode
30° S. of W.
N. 45°
Quartz, oxide of tin.
Tin Lode
25° S. of W.
N. 48°
Tin, iron, copper.
Lead Lode
20° W. of S.
E. 68°
•
Wheal Kitty
Wheal Prudence
Great St. George
Wheal Budnic
Bottle Lode
35° S. of W.
N. 85°
North Lode
35° S. of W.
N. 760
South Lode.
•
5° S. of W.
S. 50°
Quartz, galena.
Oxide of tin, copper pyrites.
Copper and blende.
Quartz, copper.
Lead Lode
•
•
36° S. of W.
N.W. 70°
Oxide of tin and galena.
ST. AUSTELL DISTRICT.
Dowgas
Polgooth.
•
Charlestown.
Pembroke
East Crennis
Fowey Consols.
""
Beam
""
Trewithen
S.E. and N.W.
•
•
•
•
St. Martin's
Tin Lode
Main Lode
8° S. of W.
35° N. of W.
N.E 68°
N. 45°
N.E. 55°
Quartz, copper pyrites.
8° S. of W.
N. 74°
South Lode.
10° S. of W.
N. 72°
Bone's Lode
4° N. of W.
N. 64°
Jeffrey's
6° S. of W.
North Lode
16° W. of S.
N. 72°
N.W. 60°
Quartz, oxide of tin.
""
Quartz, copper.
""
""
Iron and copper pyrites.
""
""
Felspar, clay, tin.
CALLINGTON.
Redmoor West
Redmoor.
Wheal Brothers
Main Lode.
Johnson's Lode
Lead Lode.
Main Lode
•
15° S. of W.
N. 50°
Iron pyrites.
10° N. of W.
·S. 68°
Iron and copper pyrites.
8° E. of N.
W. 60°
·
24° S. of W.
S. 42°
Clay and galena.
Galena, blende silver.
DEVONSHIRE.
Wheal Frances.
Main Lode
•
25 S. of W.
N. 45°
Copper, oxide of tin.
Wheal Robert
•
Wheal Friendship
Ore Lode
Main Lode.
20 S. of W.
N. 70°.
Quartz, pyrites.
E. and W.
N. 58.
Quartz, copper, and tin.
Wheal Betsy
Birch Tor
وو
4 W. of N.
W. 74°
Quartz, galena.
""
""
20 W. of S.
W. 72°
Quartz, oxide of tin.
In this list it will be seen that the direction of the mines in St. Just is-
8 are from 20° to 35° west of north, and 3 are from 30° to 45° north of west.
In the St. Ives district 9 mines run from 15° to 40° south of west, and 2 are
respectively 33° and 40° west of north. In the Marazion district we have
I lode, due east and west, 8 mines vary in direction from 5° south of west
to 25º, and 3 are from 20° to 25° north of west. In the Helstone district 3
mines are from 22° to 35° south of west, and 1 is 30° west of south. In the
Camborne district all the lodes run south of west, as they do also in the
Redruth district. In St. Agnes 7 mines vary from 5° south of west to 35º,
and I only is 20° west of south. In the St. Austell district there are 4 mines
in which the lodes run a few degrees south of west, 2 are from 4° to 35°
north of west, and 1 south-east and north-west. Around Callington 2 lodes
run south of west, one 8º to the east of north, and one 10° north of west.
309
CHAP. II.]
THE BREADTH OF MINERAL LODES.
While in Devonshire this list gives 2 mines south of west, 1 east and west
I west of north, and I west of south.
The breadth of the mineral veins varies considerably. It will be seen by
the following table that the tin and copper lodes vary from each other in
this respect. The character of the rock, its hardness or softness, its toughness,
or its liability to fissure, has an important bearing on the size of the vein.
TIN LODES.
Less than
COPPER LODES.
Less than
Districts.
100 fathoms In Granite. In Slate.
100
deep.
fathoms In Granite. In Slate.
deep.
General
average.
Feet
Feet
Feet.
Feet.
Feet.
Feet.
Feet.
St. Just
St. Ives
Marazion
Gwinnear, &c.
Camborne, &c.
Helston
•
1.81
1.86
2.0*
2.22
1.12
1.58
2.23
1.63
I'55
I-45
I.25
I.22
1.61
9*0*
•
| |
111
9*0*
2.93
2.93
4·68
1.5
2.II
2.9
•
3.4
3.3
3.68
1.86
1.18
•
3°51
2:4
2.57
3°51
2.86
Redruth, &c.
St. Agnes
1'47*
| |
3.2
3.5
3.56
3.36
•
I 17
3.55
2.45
2.74
3.09
St. Austell
7.21
5.19
Tavistock, &c.
2.0*
2.0
4'06*
2.0*
3·08
2.68
3.2
4.79
9'4
6.57
7'0
6.9 †
Mr. Carne says: "The breadth of tin lodes are exceedingly various;
their width varies from that of a barleycorn to 36 feet." In a note he
informs us that the lode in Relistian mine is of that width for 20 fathoms
only, and that in Nangiles the tin lode in some parts is 30 feet wide.
Mr. Henwood gives the following as the sizes or breadths of the lodes:-
Tincroft, Highburrow Lode
North Roskear
Wheal Vor
Polladras Downs, Bar Lode
Polgooth, St. Martin's Lode
Pembroke
""
Extreme breadth.
or 30 or 40 feet
Least size.
3 or 4. feet
1'5
foot
18 feet
""
3
feet
", 30
4 وو
I inch
I foot
", 42
inches,, 40
""
""
""
Mr. Henwood, whose observations were more extensive than those of
any other man, shows that the average breadth of lodes, of less than
100 fathoms deep, is 3.97 feet, whilst below 100 fathoms the mean size
is but 3.36 feet. The lodes in Granite are somewhat smaller than those
in Slate (this is doubtless due to the Granite being the hardest, toughest,
and least yielding rock), and tin ore is more abundant in the Granite
than in the Slate. The lodes, however, which yield the ores of both tin
and copper in a state of mixture are considerably larger than those in
which either of them is singly found. The lodes in which both these ores
together occur average a breadth of 4.7 feet. This greater average breadth
takes place, whatever may be the nature of the containing rock, or the
depth at which the mean may have been estimated. Is this due to crystal-
logenic force?
The depths to which the Cornish mines have been worked are very
various, depending of course on the value of the lodes which the miners
have been exploring. The depths of a few of the more important mines are
* These are from single examples only.
† In these averages the sizes of lodes at a greater depth than 100 fathoms are included.
310
[BOOK II.
THE FORMATION OF DEPOSITS.
given in the following table. It is an important element in considering the
problem of metalliferous veins :-
Tresavean (former workings)
Clifford Amalgamated, The'; or, Consolidated mines
Dolcoath (perpendicular depth, 365 fathoms-2,190 feet; perpendicular
from surface-deepest level, 364 fathoms under the adit. Engine
shaft, 8 fathoms under the 364 level)
Cook's Kitchen
Carn Brea
East Pool
Wheal Vor (to adit 35 fathoms) under adit
South Wheal Francis
•
Botallack (from sea-level-worked under the sea 2,448 feet).
Wheal Agar
South Wheal Crofty
South Caradon, Liskeard
Devon Great Consols, deepest shaft
Wheal Friendship, Tavistock
Bedford United
Wheal Crebor
•
DEVONSHIRE.
350 fathoms.
372
""
401
""
345
""
315
""
210
""
330 ""
223
250
""
222 "9
210 ""
275
""
300
240
""
148
""
130 ""
CUMBERLAND, ETC.-The lead mines in the North of England are usually
worked by tunnels driven into the hill,-at its lowest point,—and then the
mineral lode is followed up into the hill or worked "upon the rise."
These tunnels or levels are remarkable works. The Nentforth Level is the
longest in Alston Moor; it extends nearly seven miles. The portion between
Haggs vein and the town of Alston is an underground canal, and from
Haggs vein to Rampgill vein, it is used as an ordinary level about 180 feet
above the canal. Rampgill Level extends from the Nent River to the boun-
dary between Cumberland and Northumberland, and is rather more than a
mile long.
The Dowgang Level extends for nearly two miles. Brownley Hill is a
mile and a half long, and is ramified through the whole extent of the
Brownley Hill veins. The Browngill mines, all the Nenthead mines, and
others adjoining, are connected by levels. A distance, as the crow flies, of
about seven miles has been tunnelled to effect this.
Rampgill vein is the deepest in Alston—120 fathoms. More than three-
fourths of the lead produced in this district has been found in the 150-feet
section in which it generally occurs-the principal portion in a section of 12
feet of Little Limestone and the 48-feet of Great Limestone.
In NORTH WALES very few of the mines go deeper than about 600 feet.
In CARDIGANSHIRE about 160 fathoms, or 960 feet, may be regarded as
the average depth.
ISLE OF MAN.-The lead and zinc mines of this district are deeper.
Great Laxey, from surface
North Laxey
Foxdale
East Foxdale
""
""
•
265 fathoms.
136
""
155
105
""
""
These statements are derived from the best authorities, and they fairly
show the average depth to which our metalliferous mines have been worked.
It has been stated by many authors that veins become smaller as they
become deeper-that they are indeed wedge-shaped. Others have asserted
the contrary. Neither of those statements can be maintained as a general
rule.
CHAP. II.]
YORKSHIRE LEAD MINES.
311
Wheal Abraham, in Cornwall-when it was working-was consider-
ably larger at the depth of 240 fathoms than it was at the surface. At
Dolcoath mine the lode was largest at the depth of about 80 fathoms. Wheal
Alfred lode was much larger at the depth of 110 fathoms than at any less.
depth, but at 150 fathoms it decreased in size. Wheal Neptune lode was
9 feet wide at surface, and it was the same width at the depth of 120 fathoms.
YORKSHIRE (Teesdale).—The mining tracts of Teesdale, Swaledale, Wharf-
dale, and Greenhow Hill are considerably disturbed. Professor Sedgwick
traces a great fault as ranging down Teesdale. Limedale is on the line of a
dislocation, Swaledale is nearly parallel to the Old Gang and other east and
west lead veins. A small fault passes down Wensleydale-a remarkable
dislocation ranges east and west along the head waters of the Nid, and a great
depression about Pateley Bridge alters its course afterwards to the south-east.
Professor Sedgwick also noticed this fault from Egglestone by Lowton,
as far as the High Force. It is remarkable as a general and leading fact
with respect to mineral veins, and by consequence to the faults which almost
universally accompany them in this district, that their prevailing direction
is north of east. The greatest number of mineral veins occurs in this direction.
The greatest quantity of metallic ores is obtained from veins running east
and west. (<
This, indeed, is a general fact, for east and west courses of
veins are the normal directions for the greater part of Europe, whatever
be the age and nature of the rock including them" (Phillips). Westgarth
Forster says: "The fissure-veins of the mines in Cumberland and Durham
mostly extend from east and west, or more properly, one end of the vein
points west by south while the other tends east by north, although there
are other veins running nearly north and south, commonly called cross
veins; and it must be remarked that these cross veins have been rarely found
so productive of metallic ores as the others, excepting when the right
running veins and the cross veins intersect, in which case the cross veins
generally carry ore for some distance from the place of intersection, but
very seldom in any other stratum than Limestone, and especially in the
Great Limestone of Alston Moor."
Near Mallam, south of Wensleydale, it is in the Lower Scar Limestone
principally that the lead mines of Greenhow, Nidderdale, Grassington,
Kettlewell, Arncliffe, Hardflask, and Ingleborough are, or were, worked;
but to the north of Wensleydale the Cam Limestones become the most
productive. In the mining districts of Greenhow, Grassington, and Kettle-
well veins yield ore both in the Limestone and Millstone Grit series.
Veins have been found more or less productive in the Millstone Grit south
of Lothersdale, about Greenhow Hill, Grassington, Buckden Pike, near
Leyburn, and in the line of the Old Gang vein in Swaledale and Arkendale.
Mines are worked in the Whin-Sill at several points north of Maize-beck.
The Cononley lead mine exhibited a curious deposition of sulphide of
lead in a bed of Coal Measure shale. Calamine and white oxide of zinc
occur in considerable quantities in Yorkshire, chiefly or wholly in the
Lower Scar Limestone, as in Bolland, near Whitewell.
Upon those features Professor John Phillips founded the following remarks:
"From these facts it follows that the dependence of particular metallic
312
[BOOK II.
THE FORMATION OF DEPOSITS.
products on particular series of rocks is principally a local phenomenon without
general application; but on more minute analysis of the phenomenon it is
found that, in a given district, certain beds generally are and others gene-
rally are not productive of metallic treasures. It has been attempted, from
facts such as these, imperfectly understood, to draw a conclusion in favour of
a close and necessary dependence between the produce of a vein and the
chemical character of the containing rocks, so as to permit an inference that
the vein itself was segregated from the opposite rocks, or else that the whole is
of contemporaneous origin.*
Most veins in the mining district of Alston preserve a tolerably direct
course, often, it is said, for several miles. They are commonly called veins,
cross veins, and quarter-point veins. The first named are often called right-
running veins, and have a direction or bearing which is generally nearly east
and west, sometimes slightly varying from that to a north-east and south-
west direction. The cross veins are those which have a bearing nearly
north and south. There are a few veins which have an intermediate
bearing; these are the quarter-point veins. The "point" of a vein is the usual
phrase to designate its bearing.
If three east and west veins lie near each other, the middle one is simply
designated by its particular name; as, for example, Hudgill Burn Vein.
The vein north of this is called Hudgill Burn North vein, and that to the
south Hudgill Burn Sun vein. Sun, in the mining phraseology of the
northern mining district, is invariably used for south. If more veins be
nearly parallel, they are sometimes-as at Hudgill Burn-denominated
Second Sun vein or Third Sun vein. Cross veins, when near together, are
distinguished by the names East and West Cross veins.
In this district the names of the same veins vary in different parts.
Sir John's vein, Stoweray vein, Scar-end vein, Leehouse Well vein, for
example, are one continuous cross vein. These names are generally limited
to what is called a lease length, which is usually about 1,200 yards.
The veins may be classified into three distinct kinds. The first class
being the so-called east and west lodes, their direction, however, varying
between north 60° east and south 63° east, magnetic.
The second class comprehends the veins running in a north and south
direction. These veins vary less than the east and west veins. In
the strata above the Great Limestone they seldom contain any metallic
substances. Much lead ore has been produced from them in the Great
Limestone, and both lead and copper ores in the strata beneath it.
The third class form a set of small veins which intersect the above-named
veins. They traverse the country in two directions—south 55° east, and south
55° west, magnetic. They contain little mineral matter in the strata above
the Great Limestone. In the underlying strata they are filled with copper
and iron pyrites and earthy minerals, but very seldom contain lead ore either
in the Limestone or the Sandstone rocks. It has been observed that those
veins having a south-easterly bearing are more numerous than the others,
but they are generally poor, or, as the miner expresses it, "weak."
*“Illustrations of the Geology of Yorkshire." By John Phillips, F.R.S. 1835.
THE GREAT SULPHUR VEIN OF ALSTON.
313
CHAP. II.]
The Great Sulphur vein of Alston Moor, which has a main general direction
from the north-west to the south-east from Burnhope Seat to Cashburn Force,
varies in its mineral character in various localities. At Cashburn it is chiefly
filled with roughly crystallised quartz. Between Cashburn and Crossgill,
where the direction of the vein is indicated by a series of low rounded
hills, it consists of quartzose minerals which have resisted the decomposing
influences of atmospheric agency. At Crossgill it contains, disseminated
through the quartz, iron pyrites, which is slightly auriferous. Many weaker
strings occur here, and these contain copper pyrites, but not in sufficient
quantity to prove profitable. On the top of Noonstones, where this vein is
at its widest, it is entirely filled with quartz. At the Tyne River it contains
less quartz, and that of an impure nature. At Darngill Bridge the sulphur
vein does not vary much in character from the strong east and west veins of
the district. There is but little quartz, and the vein is filled with "douk,"*
where plate or shale forms its sides. No mining works have been made
to prove any of the east and west veins which intersect this great vein.
Browngill and Bentyfield veins are the most important of the east and
west veins of Alston Moor. The Bentyfield vein splits into strings on the
south side of Rodderup Fell vein; and at Dryburn those strings are collected
and form a vein of considerable size. A dislocation of not less than 60 feet
occurs at this point.
Several other veins besides those just noticed are thrown off Browngill
vein. Briggle Burn is by far the strongest of these. This vein increases
its width and throw as it approaches Carr's vein. After its intersection with
this cross vein it is divided into two parts, respectively termed Rampgill and
Scaleburn veins. The direction of the Coal Cleugh east and west vein is
nearly parallel to the anticlinal axis. In the Nenthead mines Rampgill vein
displaces the strata about 18 feet, in the Coal Cleugh district about 36 feet.
On the north side of Bentyfield Old Carr's cross vein, in Alston Moor, is
weakest at the north end, and increases in strength northwards. This large
vein throws up the strata.—
At Middle Cleugh Second Sun vein
At Middle Cleugh vein
At Carr's vein
At Broomsberry
At Nentsberry Green
•
42 feet
48",
60
72
162
Sopwith, who gives these measurements, writes: "It is easy to imagine
how, when the strata were separated by the formation of veins (i.e. by a
breaking of the rocks forming a fissure), some portions should sink or others
be raised from the level they occupied before; but it is not so easy to
account for the fact that, however great may be the vertical disruption of the
strata, no trace of it appears on the surface; for when the strata are removed
a distance of 100 or 200 feet, it would be reasonable to suppose that some
lofty precipice on the surface would betoken the mighty rent.”
The difficulty of accounting for this is not really so great as Sopwith
thinks. In the accompanying figure a dislocation—a downthrow-of the strata
is represented of 50 feet. The first appearance would be the formation of a
* Douk, or Douke, is a soft substance derived from the shale forming the walls of lodes.
314
[BOOK II.
THE FORMATION OF DEPOSITS.
cliff, A, Fig. 47; but in the process of time, by atmospheric action, or by
denudation by rains, there would be a wearing away of the cliff A to a line
drawn to (a), and there would be a piling up of the débris at (b) so as to
completely hide the rent at the surface.
b
a SURFACE
A
SURFACE
Fig. 47.
It is not intended to introduce any close examination of this remarkable
mineral district. A few remarks, borrowed from Mr. Wallace, on the
"Formation and Direction of Mineral Veins," will convey a sufficiently
clear explanation of the phenomena of mineral direction :-
"The Copper Dyke heads and Fletcheras veins are also formed from weak
strings, and on the west side of the Tyne traverse the district in a parallel
direction. On the east side of the Tyne all these veins are deflected in a
more northerly direction. Except Brownley Hill vein, they cease to exist
before reaching the east boundary of the Alston Manor. Near Garrigill
Burn cross vein Black Dyke vein comes into existence, and traverses the
district near to and parallel with Fletcheras vein."
It will have been noticed that in this quotation from the work of a
practical miner the veins are spoken of as if they were active agents in pro-
ducing the dislocations and disturbances of the strata. It is necessary, before
we continue the quotation, that it should be intimated that experience and
observation carry conviction to the mind that the fissures are in all cases the
result of disturbances of the Earth's surface prior to the filling in of those
cracks. After giving numerous examples of "throws," which are of but
little practical value, our author proceeds :-
"Rodderup Fell vein throws up the north cheek about 18 feet. It is dis-
placed in a longitudinal direction at the West cross vein, with this exception,
its bearing between Shield waters and Black Ashgill cross vein is very direct.
At How Hill, on the east side of the Tyne River, a strong portion bears off in
a more northerly direction, and wastes into very small portions, or leads, as
it approaches Flough Edge vein. Flough Edge and Nattrass Redgrove
veins traverse the district in a direction parallel to Browngill vein, and from
Redgrove vein a number of east and west veins split off the north side in a
somewhat similar manner; with one or two exceptions, all these dwindle to
CHAP. II.]
THE COURSE OF ALSTON MOOR VEINS.
315
nothing in their course eastward. The direction of Bayle Hill and Fistas
Roke vein is nearly parallel to Rodderup Fell vein; both are of small mag-
nitude. In the Blaygill mine the latter is moderately wide, but only dislocates
the strata about 3 feet. Thorngill veins traverse the district in the same
direction as the Browngill veins. These veins possess considerable strength.
They enter into combination, and, as Lough vein in Blaygill mine, dislocate
the strata not less than 24 feet. The direction of the Slote vein does not
vary greatly from that of the Thorngill veins. . . . . In Alston Moor the
east and west veins generally throw up the south cheek, and hade, dip, or
strike in a contrary direction.
“We shall now endeavour to prove," says Mr. Wallace, "that their
existence and direction are due to the tension to which the strata were
subjected when thrown out of their horizontal position.
"In tracing this connection we shall begin with the Browngill fissures.
Excepting the great sulphur vein, these are of much greater magnitude than
any other east and west veins in the district. To whatever phenomena veins
may be related in causation, the connection will be most clearly seen where
the greatest amount of effect is produced. At the point where the two anti-
clinal axes join in Kilhope, and at the point where Rodderup Fell vein is
intersected by the West cross vein, near Shield waters, the beds are elevated
to the same horizontal position. Between these two points is the general
bearing of the great Browngill line of fissures, consequently this series of
veins traverses the district on the level line of the strata; or, in other words,
it traverses the district nearly at right angles to the general strike of the
beds on the south side of the fissure.
"Again, from the intersection of the axes of elevation in the Kilhope
district, the beds rise in the direction of the east and west axis, and culminate
between Burnhope Seat and Dongreen, or the source of the Tyne River; from
thence, in its north-westward direction to Cross Fell smelt-mill, they incline
considerably. Now,. in their direction from east to west, the magnitude and
throw of the Browngill fissures vary in the same or a corresponding manner.
This vein, or fissure, exists in its greatest magnitude precisely opposite the
point where the strata are most elevated on the line of the axis, and in propor-
tion as the strata incline in each direction from this highest point of elevation,
so do the magnitude and throw of Browngill vein diminish.
"The Browngill fissures are not only the greatest in magnitude but also
in extent of those having a similar direction in Alston Moor. In the Nent-
head district the Briggleburn veins traverse on a level line with the strata.
In the Coal Cleugh district the beds incline a little in the direction of the
veins eastward, and, as they approach the Swinhope district, their direction
is not parallel to the axis. Next to Browngill, Fletcheras vein is the strongest
of its class in Alston Moor.
((
Except Crag Green Sun vein, which terminates at Old Grove's veins, no
veins are thrown off on the north side of Fletcheras vein. The other east and
west veins of Alston Moor are related to the same phenomena as Browngill
and Fletcheras veins, and are dependent on the same laws of causation, and
were formed contemporaneously with them. Their magnitude is proportional
to the intensity of the elevating forces, as denoted by the effect upon the
316
[BOOK II.
THE FORMATION OF DEPOSITS.
strata, and their direction varies as the dip, or, to speak more forcibly, their
magnitude and direction are proportional to the amount of twisting or wrenching
undergone by the strata, when their horizontality was disturbed by subterranean
forces, either of elevation or depression."
Cross Veins.-In Alston Moor the veins bearing north and south, usually
in the district called Cross Veins, generally traverse those which are termed
right-running veins, which pursue a point nearly east and west. The
celebrated Werner* laid down the rule "that every vein which intersects
another is newer than the one traversed, and is of later formation than those
which it traverses; of course the oldest vein is traversed by all those that are
of a posterior formation, and the newer veins always cross those that are
older." In applying this rule it is necessary to determine the intersected and
the intersecting vein, which is not always easy. Werner again says: "When
two veins cross, one of them without suffering any derangement or interrup-
tion, traverses the other, this last is interrupted and cut across through its
whole thickness by the former. The first of these is said to traverse the
other, and the latter to be traversed by the latter."
Westgarth Forster observes, that in Alston Moor the veins bearing
north and south traverse the east and west veins, and he infers, therefore,
that the cross veins are the most recent. Professor Phillips, speaking of the
metalliferous veins, and of the great lines of disturbance, observes "that the
numerous faults of an ordinary character are evidently related to and dependent
upon them. It appears possible, certainly, to distinguish two periods of
disturbance: one, the older one, being marked by an east and west direction
—these are essentially the most important mineral veins—and the other by a
north and south direction, being generally whin-dykes and some few mineral
veins."
In the strata above the Great Limestone, the lodes contain but few sparry
minerals, the cross veins in this respect differing considerably from the
east and west veins. In some parts of the cross vein, large masses of metal-
liferous minerals are found, while in others but little removed from them
blue clay alone is discovered. The mineral contents of the cross veins in
Alston Moor are generally softer and less compact than the contents of the
east and west veins. The cross veins may therefore be considered as a
marked class, distinguished in many ways from those which take an easterly
and westerly direction.
The following are the most important Cross Veins which traverse the
Alston Moor and Coal Cleugh district.
The Coal Cleugh east cross vein. The Coal Cleugh west cross vein.
Pump Sump Cross Vein.-This is supposed to be identical with the Long-
hole lead vein of the Kilhope district.
The Bounder End cross vein dislocates the strata but very little. On each
side near its intersection with Rampgill vein, extensive flats of lead ore have
been found.
Rampgill and Scaleburn are found farther west in the Nenthead district.
In its course northward the Rampgill vein combines with the cross veins
which traverse the rocks of Alston Moor, on the east side of the Nent River.
* "New Theory of the Formation of Veins," chap. iii. sec. 31.
CHAP. II.]
THE CROSS VEINS OF ALSTON MOOR.
Carr's vein and Wellgill cross vein are found in the Haggs mine.
317
Black Ashgill-on the north side of Capel Cleugh veins—is of consider-
able magnitude. On the north side of Dowgany veins it is ramified into
several portions. Between the Grassfield and Hudgill Burn mines it is a
vein of moderate, strength, divided into two branches. Northward from
Hudgill Burn it gradually diminishes in width and throw. In Foxeshield
mine it is found in two portions, of but little importance. On the north side
of Blaygill Burn it diminishes to a mere string.
Where the Black Ashgill vein intersects with the Dowgany veins two
weak veins are formed, one passing through the Hudgill Burn lead mine, the
other crossing the Nent River, and ceasing to exist.
Garrigill Burn-or Old Groves-is the next cross vein of any importance.
Windshaw Bridge is another cross vein, whose direction corresponds with
the course of the Tyne River.
Sir John's cross vein is on the south side of the Great Sulphur vein. It is
split into two portions on the north side of Crossgill, and becomes very wide
at the point of intersection with Rodderup Fell vein in the Slaggy Burn
mine. Like some of the Nenthead cross veins, by inclining to each other,
these dislocated sections must become one vein at no very great depth below
the surface.
Rodderup Fell cross vein has not been found on the south-west side of
the Great Sulphur vein.
Some weak cross veins intersect Crossfell vein near the Smelt Mill, and
these are probably identical with the Nether Hearth Cross vein.
These cross veins are evidently of a different age in Alston Moor from
the east and west veins. The east and west veins are usually found inter-
sected by the cross, or north and south veins. Mr. Wallace endeavours to
establish the following proposition: "The cross veins in the mining district
of Alston Moor were formed either anterior to or contemporaneously with
the veins which traverse the district in an east and west direction." After
examining with much care all the conditions observable in the mining
districts of Alston Moor, this observer remarks: "We are now in a position
to affirm that the cross veins, as well as the east and west veins, were in
existence soon after the close of the Coal Measure period and before the
formation of the lower Permian rocks. The Magnesian Limestone rests un-
conformably upon the former, and the ninety-fathom dyke passes underneath
the latter without dislocating its beds."
The Quarter-point Veins.—This class of veins is generally of very small
magnitude, and the disturbance produced by these fissures is but of a few
inches.
In the northern part of the district, the strongest of these veins is the
Rampgill second sun vein in the Nenthead mines. For 180 fathoms Ramp-
gill vein traverses the district in the direction of the quarter-point vein.
In the lower part of the district, veins of this class appear to be much
stronger. There is one in Rodderup Fell mine bearing a north-east and
south-west direction, which throws the north-west side up about 40 feet.
This vein is parallel with several dykes or veins of considerable magnitude
found in the old collieries situated at Gilderdale Head.
318
[BOOK 11.
THE FORMATION OF DEPOSITS.
The veins of large throws in Swaledale are generally cross veins, and
have a direction north and south, or north-west and south-west. The cross
veins of large throws are usually unproductive. When productive it is
generally in the Limestone. The east and west veins of large throws, when
productive of lead ore, are frequently so through the whole strata.
In looking through a large number of sections of the strata it becomes
evident that the most productive portions of the vein are those which have
Limestone beds on either side, and really these sections afford but very slight
support to the view that the metalliferous deposit is to any considerable
extent regulated by the physical differences in the enclosing beds. All the
productive lodes are found between the "crow lime" and the "underset
Limestone" in this district.
The Crystalline Rider is composed of such substances—not being lead
ore-as are found in the vein, as calcareous spar, fluor-spar, carbonate
and sulphate of baryta, silica, iron pyrites, oxides of zinc, and the like.
The Sedimentary Rider consists of any friable or tenacious earthy
substances found in mineral veins, as whamp or vamp, donk or douk, or
platy sample.
"The primary rider is so termed because it is the broken portion of the
bed or beds thrown in between the sides, cheeks, or walls of the vein, and
consequently its origin was contemporary with the vein itself. In the
secondary riders we have the growth of all crystalline and metalliferous
(mineral ?) substances; and in the tertiary we have the general filling up of
the vein with sedimentary deposits chiefly from the disintegrated portions of
the strata.'
Limestones and Cherts are regarded as the most productive deposits in the
northern mines, but we have not seen any reason assigned for this. Grits
and Plates are, as already stated, considered as unproductive deposits, but no
good examination of the causes regulating this has been made.
The directions of veins in Swaledale are as follows: Those of small throws
have a general bearing of west and south-west, to east and north-east, and
these are stated to be the most productive of lead ore, from having ore-
bearing beds, on each side of the vein nearly opposite to each other.
As a general rule, lead and iron lodes run either north and south or
north-north-west and south-south-east, the copper lodes east and west, in
the Keswick, or the Lake District.
The direction given is the true bearing; the miners using magnetic
bearings; so that a lode coursing magnetically north and south has, geo-
graphically, a course of about 20° west of north.
The Keswick United Silver Lead Mines, Thornthwaite Lodes.-The Thorn-
thwaite lode hades east, is sometimes 20 feet wide, and very gossany at the
top. With the galena there is much blende, and some carbonate of lead
This in nearly all cases is due to the infiltration of water containing
much carbonic acid in solution. Rachel Wood lodes, Beckstone vein, and the
Ladstock lodes have not been worked for many years.
Glenderaterra Lodes.-
occurs.
* "An Inquiry into the Deposition of Lead Ore in the Mineral Veins of Sw aledale, Yorkshire." By
Lonsdale Bradley, F.G.S. 1862. A considerable amount of useful information has been collected and
recorded in this volume with special reference to this district.
CHAP. II.]
MINES OF THE LAKE DISTRICT.
319
The oldest workings on these lodes date back about sixty years. They are a
little south of Roughton Gill. A small lode was opened upon in 1872, but
the work has been abandoned. Blencathera lead vein, called Saddleback, lies
twelve fathoms east of the shaft, and was worked about fifteen years since.
In the Lonscale crags on the west side of the valley are several strings
which fall into the lode and render them productive. Blende in consider-
able quantity exists in this lode. Curious deposits of brown and red iron
ore have been formed in the level within the last twenty years. These
beds are, of course, the result of oxide of iron precipitating from the per-
colating water. Wood End lode and Gate Gill are found to change their
hade considerably, and appear to yield best where the inclination is least.
The Loweswater Lodes were worked nearly forty years since, and a con-
siderable quantity of lead extracted from them. Several small workings
have been carried on within the last half-century. Newland's Vale Lodes.-
These are Sealby's lode and Scope End lode. Never very productive. The
Castlebrook Lode.-This lode hades east and courses very nearly north and
south. In connection with it is another lode, sometimes called Francis lode,
containing very rich-looking lead ore in a crumbling quartz.
The Yewthwaite lode runs north-north-west and south-south-east, hading
to the north-east at an angle of 75°. Carbonate of lead and a good deal
of blende have been found in this lode. The Barrow lode is a continuation
of the Yewthwaite. This lode greatly resembles the Thornthwaite, only
occasionally yielding good bunches of lead ore. The Stonycroft lode joins
the Yewthwaite and Barrow. It was worked twenty years since. Around
Rowley End are evidences of many old workings, but nothing is known of
them. The Brandelhow lode has the usual north-north-east and south-south-
west course, hading east. The lowest workings in this mine were at 50
fathoms; none were carried for a greater distance than 1,500 feet from the
lake, measured along the lode. A saline spring occurs in Brandelhow mine,
which is taken medicinally by the country people. It contains much
chloride of sodium and some sulphate of magnesia.
Three veins have been worked known as the Helvellyn lodes, in the
Wythburn lead mines. The Old Vein and the Blue Rock, the former hading
east and the latter south, yield lead, much of it argentiferous. These lodes,
from the difficulty of working them through the Serpentiferous dykes, have
never been successfully worked.
Its general course is
The width varies con-
The Greenside mine is the richest in the county.
but a few points west of north, and its hade is east.
siderably, there being sometimes strings of ore through a breadth of 40 feet.
In Grisedale Valley are three lodes, the workings upon which are very old,
but apparently unprofitable. The Eagle Crag vein, with an east and west
course, hading a little to the south, but nearly perpendicular, has been
recently opened, but has not proved productive. The Ruthwaite Lodge or
Tongue Vein.-The workings here are mostly old, but of late very little has
been done. Hartsop lode has been worked upon in ancient days, and yielded
a little lead and some blende.
WALES.-The importance of several of the districts of Wales indicate the
advantage of considering them in the next plâce.
320
[BOOK II.
THE FORMATION OF DEPOSITS...
Nearly all the productive mineral veins in the counties of Cardigan and
Montgomery have a strike east-north-east and west-south-west. Goginan,
Darren, Cwm-symlog, Logaulas, and many other large and productive.
deposits, agree within a few degrees of this course. Tre-Taliessin, which
returned considerable quantities of lead ore, runs north-west and south-east.
At Cwm-ystwith the main lode points east-north-east, while the "comet"
lode courses west-north-west. Many of the lodes to the east of the Rheidol
show a northerly turn, and on the outskirts of the main metalliferous districts
several small lodes yielding ore conform with the direction of the meridian,
as Pant Mawr and Siglenlas on the south-east, Rhysgog on the south,
and others on the north.
The "underlie,” or inclination of the lodes, is most frequently to the south,
but there is much irregularity in this. At Esgair-Hir, Darren, and Delife
the underlie is to the north-the variation being between 60° and 80° from the
horizontal. The filling matter of the mineral vein is principally slate-in
angular fragments of all sizes, from small particles intimately mixed with
the lead ore, to large masses which frequently appear to divide the lode.
This clearly establishes the fact that those veins are rents or fissures formed
by convulsions, the lines of these cracks showing the direction in which the
wave of disturbance has moved. Quartz is usually associated with the lead
ore in all these veins. The hard and massive silicious matter which forms
irregular veins in the Slate is not regarded as a favourable indication, whereas
the cellular, granular, and powdery spar is looked on by the lead-miners
as promising for ore.
Calcareous spar occurs in many of the lead lodes. It is often found
in veins, and sometimes of considerable size. In the bed of the Ystwith
is a vein of calc-spar ten feet in width. At Henfwlch Mr. Smyth says it
is met with in large ribs, and encloses small quantities of copper, lead, and
zinc ores.
Similar appearances are evident at Esgair-Hir. In Montgomery-
shire calc-spar is also abundant.
Sulphate of Baryta occurs near Llanidloes, in a vein at Cwm Mawr, and
at Llangynnog. Carbonate of Baryta (Witherite) is associated with large
masses of lead ore at Pen-y-Clyn, and in some other mines it is found in the
veins.
Fluor-Spar, so commonly found in the mines of the North of England, is
scarcely known in the lead mines of this district.
Galena (sulphide of lead) is the usual metallic ore of Cardiganshire and
Montgomeryshire. Most of it contains silver, often up to the proportion
of 75 oz. to the ton of lead. White lead is found in a few lodes particularly
near the surface, evidently formed by the action of water holding in solution
carbonic acid. This carbonate is sometimes found at considerable depths,
but only where there has been a long-continued flow of water through
the galena of the lode.
The Phosphate of Lead (Green lead ore, pyromorphite) is found tinging the
lead ore-but only where it has been exposed to the action of water containing
decomposing organic matter.
Zinc ore (black jack) is found, but not on the whole so abundantly as the
galena. It occurs frequently in thin strings and small patches in the poorer
CHAP. II.]
MINERAL VEINS OF CARDIGANSHIRE.
321
lead veins. There are but a few mines in which it is found in sufficient
quantities to pay for mining and dressing, at the low prices which have
prevailed for several years. Calamine, the silicious species of zinc ore, has
been found at Nant-y-Creiau, but it has not been worked for some time.
Copper ores are not found to any extent in this district. Copper pyrites
have been worked at Tre'rddol, and this ore exists of a fine quality in Cwm
Ricket, near Llanidloes, in the bed of the Severn.
Iron Pyrites, brown iron ore, and manganese ores are found in various
parts of the county, and they have been occasionally mined.
Studying the phenomena presented by the mineral veins of Cardigan-
shire, we find but little to establish the views which have been promulgated
in reference to the deposits of metalliferous minerals in other districts. There
is but little regularity in the deposits of the lodes. "Generally," says Mr.
W. W. Smyth,* "we may observe that calc-spar takes the inner side of the
quartz,—whether in drusy cavities or in ribs,—and it would appear that the
galena occupies an analogous position with regard to the zinc, a point of
great importance as bearing on the theory of these mineral veins and its
future application to mining."
α %
a
a b
Lead Lodes in Cardiganshire.
Fig. 48.—a, zinc blende; b, galena; c, quartz. | Fig. 49.—a, copper; b, quartz; c, zinc blende;
d, pyrites; e, galena.
The annexed diagrams (Figs. 48 and 49) are sections of two lodes. The one
is at Nant-y-Creiau and the other at Tyn-y-fron. It is not often that we are
enabled in the lodes of Cardiganshire to refer to this banded structure, as
showing that the deposits in the fissure took place at different times. Gene-
rally the lodes are brecciated masses of angular fragments of Slate rock,
cemented by mineral matter. Observations on the lodes of Cardiganshire
and Montgomeryshire do not prove that the ore-bearing character of the lode
has any relation to the direction, nor is it satisfactorily shown that there
is any connection of productiveness with the dip of the veins. When two
lodes approach each other at a small angle the junction is usually marked
by a larger deposit of ore, and when branches or smaller veins fall into the
main lode, whether on the line of strike or on the dip, the vein is enriched.
Where veins have combined it is commonly found that a large mass of lead
ore has been found. The returns of lead ore raised in this county show a
considerable falling off.
The lead veins of Cardiganshire do not vary—as do the lodes of Cornwall
and elsewhere—when they pass from a harder to a softer rock. The vein and
the rock through which the lode passes are frequently found to be of the same
"On the Mining Districts of Cardiganshire and Montgomeryshire." By Warington W. Smyth.
("Memoirs of the Geological Survey of Great Britain," vol. ii. part 2.)
Y
322
[BOOK II.
THE FORMATION OF DEPOSITS.
character. "The rock, as in all the Goginan districts, is so solid that its
bedding would be indistinguishable but for the stripes of a darker colour
which here and there relieve its pale grey tint; but where the lode passes
into the 'cross measures'—as they are termed--of Slate, not a vestige of ore
remains to tempt the miner onward” (Smyth).
FLINTSHIRE VEINS.-The Holywell Group.-The mineral veins generally
take two principal directions, the one nearly east and west, the other north
and south. The east and west lodes are the most metalliferous. The north
and south are often quite unproductive, and are seldom rich, except in the
neighbourhood of the east and west lodes.
In the case of the intersection of two lodes of different systems, if one
is heaved it is the east and west which is heaved by the north and south.
The north and south lodes are also known under the name of "cross courses.”
In a case where-as in the district of Holywell-shale is met with above
the chert, the miners stop the work when they come in contact with the shale.
These rules have been adopted from all antiquity by the Welsh miners
in every mine. The particular manner in which the old works were carried
out, serves to guide the managers of the mines, and the agents acting
under their orders, in their search for mineral deposits and in prosecuting
their excavations. The mine of Holywell Level comprises the great east and
west lode of Holway and numerous cross courses. Old workings have been
conducted in some east and west lodes, but these are less important, and
situated to the north of the main lode, which extends over a length of three
miles following a general direction of west 5º north. In the neighbourhood
of the Victoria shaft it is nearly west 15º north, east 15° south, as indicated
in the following rise made in the 140-yard level:
Indications of
the Compass.
1230
124°
123°
135°
1381/0
1261°
To the East.
To the West.
Successive Distances
between the Points
of Observation.
46 yds. 6 in.
34,, 6 6,,
29
47
63
42
"9"
""
""
3 ",
4 ",
7
""
3 ",
304°
55 ",
""
Admitting 20° for the actual declination, and taking 125° for the mean
direction, we shall have 125° 20°-90° = 15º.
The underlie is towards the north, and in the deep part it is regular and
at 9 inches per yard 1; in the upper part it is very variable, and presents
in the chert a series of steps.
The cross courses are directed north 258 to 0° east; their inclination
(always very great) is for the most part to the east, but sometimes to the west.
The works have been pushed to a depth of 150 yards; a long adit level,
at a distance of 61 yards from the mouth of the Victoria shaft, carries the
water from the Holywell into the valley and takes it as far as the town.
The ancients, who had followed the north and south lode in the black
Limestone, were stopped by meeting with a schistose rock; although the
lode became thin at once, the trace of it could still be distinguished. How-
ever, fearing they should meet with a shale formation, they abandoned the
CHAP. II.]
THE HOLYWELL GROUP OF VEINS.
323
works. The actual manager, suspecting their error, pushed the gallery on
some yards, and again came upon the lode in the chert; and the lode, after
having been reduced to less than an inch, became again 2 feet in width.
The north and south lodes in the mine of Holway are less important
under all circumstances than the main lode east and west.
In following the level, the intersections can be clearly traced. Generally
the north and south lodes cross it without any deviation. Sometimes, by
chance, the north and south lodes in the chert are heaved two or three
yards; and considering the weakness of the cross courses, relatively to that
of the great east and west lodes, and to the nature of the rock, these heaves
have nothing characteristic. The north and south lodes, of which some
incline to the west and others to the east, appear to re-unite after obtaining
some depth. The rock beds dip north-north-east. At the roof of the lode in
the upper part of the mine a shale is found, which is black and solid enough
to sustain itself in a horizontal position sometimes for a space of ten yards.
Chert, generally black, takes, in productive regions, a bluish tint, often
very clear, and with a translucent appearance quite characteristic. This is
known by the miners under the name of bearing chert.
The blue chert is represented by beds of bluish schists, such as are met
with in the cross course; while the black is characterised by an argillaceous
Limestone, perfectly black, and having crystalline veins impregnated with
liquid bitumen. The white chert is of a very pale grey-yellow.
The ore from the east and west lodes is almost exclusively a sparry
carbonate of lime, containing veins of galena and blende.
The spar is generally white, and formed of crystals pressed together in a
confused mass. However, geodes are sometimes found containing crystals
more clearly defined, not only of spar, but also of galena. They have been
discovered at a depth of 10 or 12 feet, of 1½ foot in width and 5 feet in length,
in the direction of the lode. Near the ore the spar takes the pale tint, much
prized by miners, who call it bearing spar. In the north and south lodes the
ore is still principally in the spar, but with a large proportion of yellow
clay. This clay forms the bed of the lode, and often also the intermediate
beds in the spar. Fragments detached from the sides are frequently found
embedded in the white spar.
The clay which abounds in the north and south lodes is also met with, but
in less quantity, in the east and west lodes, the ore of which is poor.
Galena is, as at Holway, more earthy in the cross courses and more
laminated in the east and west lodes. There is very little blende, and it is
only met with in the east and west lodes.
Carbonate of lead is found in considerable quantities in all the lodes, and
some calamine, with this peculiarity, that the carbonate of lead lies princi-
pally in the east and west lodes, and that the calamine seems altogether
absent in the chert.
In a cross course of 20 inches, at a distance of 8 yards from a north and
south vein which bears the mineral, lead, copper pyrites, and blue and
green carbonate of copper are found.
The direction of the main lode in the Maes-y-Safn mine is west 24° north,
east 24° south. To the west a string branch is also worked.
Y 2
324
[BOOK II.
THE FORMATION OF DEPOSITS.
The vein inclines towards the north; towards the west the inclination is
75°, to the east it is not more than 50º-in 1,200 yards. The cross courses,
north 7º west and south 7° east, which are not numerous, are completely
barren, and contain only carbonate of lime and clay: they bring into the
mine an enormous quantity of water, which, in spite of an adit at a depth of
100 yards, is very difficult to get rid of.
The works have been pushed to a distance of 250 yards in the white
Limestone, above which lies a certain thickness of Aberthaw lime. The beds
tend towards the south-east; they are covered to the east by Sandstone. At
Maes-y-Safn, galena is found, and a little blende-which is considered a bad
augury for the richness of the lode-which carries neither calamine nor fluor-
spar.
The lode is seen cropping out on the surface, causing a fault in the
Limestone. The ancients have made very deep excavations at the foot of the
escarpment which it has formed. The Sandstone advances through the
Limestone chain to the south of Maes-y-Safn, about three-quarters of a mile,
forming an elevated and almost barren plateau, which inclines a little east
of south. It is in this region that the rich mines of Bwlly and Jamaica
were discovered.
ANGLESEA.-Having dealt with the rocks of this island in their relation to
the mineral lodes, it only remains to direct attention to some conditions
which are more closely related to the questions treated of in this chapter.
Sir A. C. Ramsay* suggests that the alteration of the strata of Parys
mountain was effected deep underground, probably under the influence of
heat and moisture, the altered strata having since been exposed by denuda-
tion. The fracturing of the country by faults, he thinks, is of a much later
date than this early metamorphism, and the cross faults and copper lodes of
the mountain belong to that later period, but running, as the great original
deposition of copper pyrites did, in the line of the strike of the slaty
band between the hard rocky masses. He also thinks it is by no means
certain that the ore may not have been introduced in solution into the strata,
some of which helped to produce the metamorphism of the large hard rock
band, and which seems to have impregnated the original sediment with an
extra amount of silica.
Mr. Henwoodt informs us that he found numerous examples of copper
pyrites and vitreous copper ore dispersed in irregular and unconnected masses,
and in minute veins, through the Slate in Parys mountain. The termina-
tion of these veins is abrupt; they are lost without any intervention of joints
or cross veins, and they reapper within the distance of a few fathoms.
Isle of Man.—The principal mines of the Isle of Man are Laxey, Foxdale,
and Brada Head. These lie in the Grauwacke formation, with the exception
of the small-grained Granite, which exists at Foxdale. The direction of
the vein at Laxey is west-south-west and east-north-east, and at Brada Head
there is but little deviation from that direction; the inclination of the lead
lode at Laxey and Foxdale, with respect to the horizon, is two yards in six.
"The Geology of North Wales." By Sir A. C. Ramsay, LL.D., F.R.S. ("Memoirs of the
Geological Survey." 1881.)
"The Metalliferous Deposits of Cornwall and Devon." By William Jory Henwood, F.R.S. 1843.
CHAP. II.]
ISLE OF MAN MINES.
325
At Laxey mine the galena is very pure, its specific gravity being
7.652. The Bishop of Llandaff states that the produce of silver was 20 oz.
to the ton, but it has occasionally risen so high as 35 oz. In connec-
tion with the galena, carbonate of lead and fibrous carbonate of copper are
occasionally found. The walls of the vein are formed of a fibrous, silky
Grauwacke, with lamellar crystals of calc-spar and pieces of bitterspath, the
rider or vein-stone being a breccia composed of grauwacke, quartz, bitter-
spath, and brown blende.
At Foxdale the lead ore has a specific gravity of 6·095. The vein is filled
with blue and white chalcedony, galena, and some iron pyrites. Sparry iron
ore in large lamellar crystals of a dark colour is also found in the lode, the
galena adhering to it; grauwacke forms the south cheek or side of the vein.
Brada Head gives a less pure variety of galena, its specific gravity being
6.622 the vein-stone or rider being a yellowish quartz, enclosing iron
pyrites.
Wolfram has been occasionally found in the Isle of Man, but rarely in any
useful quantity.
The name Tinn-wald, at St. John's Chapel, has sometimes led to the idea
that tin existed in the island. According to Dr. Berger, tinn-wald is a
Danish word—tiny, a court of justice, and wald, fenced. The court was held
on an artificial Mount near the middle of the island. It will be curious to
trace if any relation exists between this Mount and Crockern-Tor on
Dartmoor, as both have been courts of justice for mining cases.
The following statement has been obtained from Mr. Kitto of the Foxdale
mines, than whom no one is better informed on the question of the Isle of
Man mineral lodes :-
"I think I am quite right in saying that the general direction of the north
and south lodes is from 8° to 12° east of north, with an eastern underlie of
2 feet in the fathom. This refers to the Laxey, Snaefell, and Bradda lodes.
The Ballacorkish lode is also north and south with a western underlie of two
feet per fathom.
"In this district of Foxdale the principal lodes run 8° south of east, with
a south underlie of 2 feet per fathom. We have traced them in our Fox-
dale mines for over 3 miles in length, during which they have been
intersected by several oblique veins, and also by at least three north and
south veins, all of which have a western underlie of about 2 feet. In our
western mine, known as 'Beckwith's,' the 'Wardells,' north and south, cross
the main east and west lodes; and two miles farther east, lodes known as
'Old Foxdale,' 'The Mayhies,' north and south-and the 'Flappy,' north
and south-cross the main or east and west lodes. All of those north and
south lodes have yielded silver lead ore, but not in such quantities as the
east and west lodes. The 'Cornelly' lodes, which are about one mile north
from Foxdale, have the same direction, viz. 8° south of east, but their dip or
underlie varies considerably, still it is south.
"I need hardly say that in 'Old Foxdale' we are now permanently
down into the Granite, and we have passed through a 'floor' of Granite at
'Cornelly' (now Townshends), about 30 fathoms thick, but into the Slate
again. All the other mines on the island are in the Slate. The depths of
326
[BOOK II.
•
THE FORMATION OF DEPOSITS.
the mines belonging to this company now at work are-Old Foxdale, 200
fathoms below adit; Mayhies, 84 fathoms below adit; Townshends or
Cornelly, 125 fathoms below adit; Great Laxey, 259 fathoms below adit;
Snaefell is 130 fathoms from surface; Bradda, 70 fathoms from surface;
Ballacorkish, 60 fathoms below adit. In the Great Laxey the main lode
and some others of the north and south lodes underlie eastward.
"Personally, I do not like to see a north and south lode in the Isle of Man
carry its head' to the west of north; neither do I like an east and west lode
to 'carry its head' to the north of east.”
IRELAND.-In the Limestones of the counties of Cork and Limerick,
argentiferous galena, copper ore, blende, and iron pyrites are found. In the
townland of Cloghatrida, which lies a little to the west of Stoneville, there is
a lode which contains all those minerals in a gangue of calc-spar and rotten
ferruginous Dolomite. The lode runs nearly east and west, and underlies north
at 70º. In the line of the strike of this lode the same ores were found, and
to the south-east of the railway a lode bearing about north 45° east.
liable in some
When a streek
Near St. Crohan's hermitage on the Coomakista ridge, between Lough
Currane and Westcove, in Kerry, a quartz vein was found bearing east 10°
north underlying north-north-west at about 80°. This vein or lode was
traced for a distance of nearly two miles, but it varies much in size and has
not always the same underlie. Sir Richard Griffiths, in his list of Irish
mines, names, as a locality for lead, a spot east-north-east of Milltown. A
lode was examined here having a dip to the south-south-east at about 60°.
In Ross Island a mine producing copper was worked; and Raspe, in 1761,
reported on a lead mine in Cahernane Demesne, Killarney.
SCOTLAND.-Williams notices that mineral veins are
districts in Scotland to be "thrown off their level by slips.
vein is thrown up or down, out of its ordinary course and level by one of
the rake or slip veins, if the slip happens to be tolerably wide and to contain
more or less of ore, or of other promising mineral soil, the miners will
follow the rake vein up or down, whichever way it has thrown the streek,
until they meet with it again, and then they will work one or both of them
as they approve or appears worth while; but on the contrary, if the slip or
rake vein happens to be a close switch in that place, and thus the two sides
are close and cemented together. In that case there is the more danger, as
some of those slips which throw the strata and flat veins a great many
fathoms up or down are so close and imperceptible that the flat veins may
be lost without the utmost attention. I. When the vein is cut off by the
slip and thrown off its former level, the miners meet firm stone in the
face instead of the new vein; and when they touch this stone, if they
are perfect in the history of the strata above and below these veins, and
recognise the stone which meets them in the face, they can then make a
near guess how far the vein is thrown off its former level. If it is a down
slip, the vein will be cut off first above; but on the contrary, if it be an up
slip, it will be cut off first below, and there will always be some small
vestige, although it should be no more than a close joint, to show which
way the ore is gone."
CHAPTER III.
THE LAWS RELATING TO MINERAL DEPOSITS.
THE result of training—that is, of instructing men in a knowledge of such
sciences as bear upon mining—is very strikingly exemplified in the number
of Saxon philosophers, and miners, from whom we have derived most of our
theories-perhaps it would be safer to call them hypotheses-which relate to
the formation of veins or lodes. Werner says: "Agricola, Rösler, Henkel,
Hoffman, Oppel, Charpentier, and Trebra have furnished all the information
we possess on the subject. Nor is this surprising, when we reflect that it is
chiefly the philosophers and miners of Saxony who have formed the art of
mining into a distinct branch of science, and who have carried their researches
on this subject to the greatest length, and created some of the accessory
sciences,—as the chemistry of smelting ores and subterranean geometry."
Becher, who wrote in 1669, ascribes the formation of metals and minerals
to certain subterranean vapours which, arising from the bowels of the Earth
and penetrating the veins, produce a peculiar change.*
Balthasar Rösler, who was mine-master at Altenburg, died in 1673. It
was not until 1700 that, at Dresden, his "Speculum Metallurgia Politis-
simum," folio, was published, promulgating views which were to some
extent adopted by Werner.
Stahl, the German chemist-one of the most remarkable of men-followed
Becher in many respects. He concludes, however, by setting aside Becher's
theory, and considers veins, as well as the substances of which they are
composed, as having been formed at the same time with the Earth itself,
and, of course, as being of the same age with the rocks in which they occur.†
Henkel attributes the formation of the contents of veins to a peculiar
exhalation produced and engendered by a fermentation, supposed by him to
take place in the interior of rocks. The basis of each metal and mineral he
supposes to exist already in the substance of the rock, and that by a peculiar
process of nature it is matured and converted into metal. Henkel clings to
a few of the alchemical hypotheses: for example, he speaks of "subtile
earths;" again, of mercurial, arsenical, and sulphureous parts. ‡
Hoffman, born at Leipsic in 1741, was appointed Assessor to the Council
of Mines at Freyberg, and after Henkel's death he delivered lectures on
Mining. Eventually he obtained the rank of commissioner of mines, and
*Joh. Joachim Becheri, "Physica Subterranea." Lipsia: 1703. The first edition was published at
Frankfort-on-Main in 1669.
† Georg. Ern. Stahlii, "Specimen Becherianum." 8vo. Lipsia: 1703.
+ Joh. Fr. Henkel's "Pyritologia; or, History of Pyrites."
+
Chymicorum." Dresden and Leipsic: 1727.
Leipsic: 1725. And "Medicorum
328
[BOOK II.
THE FORMATION OF DEPOSITS.
soon afterwards he took charge of the mines of the King of Naples. Hoffman
supposed veins to have been formed in the fissures of rocks, which were
gradually filled in by the separation of mineral matter from the waters
flowing through them.*
Zimmermann was a pupil of Henkel's, and chief commissioner of
mines. He says: "Minerals are undoubtedly formed in the rock, but daily
experience shows that the rock is not of itself capable of forming a metal, for
were the mineralising principle capable of converting it into a mineral we
should find whole mountains which had undergone this change; but this
change we only meet with in some parts, which follow certain directions, and
being thus transformed, constitute veins. The veins, when they have not
suffered the entire change, or when they do not contain perfect minerals, are
still of a different nature from the rest of the rock. An attentive examination
will show that they are of a decomposed and friable nature, appearing to have
a tendency to return to their natural earthy state; from which we may conclude
that the veins were in reality originally the same as the rock, but that the
texture had been altered and decomposed by some particular saline substance
which, penetrating the rents and fissures, had rendered them fit to be trans-
formed into minerals. In this way saline substances prepare and render the
earthy matters capable of being converted into the matrix of minerals. These
same saline substances also assist in the formation of metals. To this we
cannot withhold our assent, if we admit, what experience teaches, that all
minerals are mixed bodies, consisting of a metal, an earth, and an acid.” †
Von Oppel was Captain-General of the mines of Saxony. In his "Subter-
ranean Geometry," published at Dresden in 1749, he writes:-
By a vent is understood an empty fissure or gap in a rock. Vents are
generally narrow, mere cracks in the rock.
“A vein is a fissure extending a great way through a rock, which it cuts
and divides. It is filled with materials different from the rock. Fissures
and veins do not run in the direction of strata of the rock, they traverse and
intersect them.
"A bed is a mineral deposit, the nature of which differs from the other beds
and layers of the same mountain. It has the same direction as the strata of
the mountain."‡
Von Oppel admits to the full that veins were formerly fissures open in their
superior parts.
Werner quotes with approval the following passage from Von Oppel's
essay on the "Working of Mines":-
"The natural structure of the globe seems to show us that, after the
formation of the primitive and principal secondary mountains, they had
suffered great desiccation and been exposed to violent shocks. In conse-
quence of these changes the rocks and mountains, which formerly composed
one continuous mass, were split asunder. Whilst this took place, it might
easily happen that one of the rocks slipped from the other without ceasing to
*Jo. Georg. Hoffmanni, "Dissertatia de Matricibus Metallorum." 4to. Lipsia: 1738.
+ Carl. Fred. Zimmermann, "Obersachsische Bergakademie." Leipzig: 1749.
"Anleitung zur Markscheide kunst nach ihren anfangs grunden und ansübung kurzlich
entworfen." 4to. Dresden: 1749.
CHAP. III.]
HYPOTHESES ON MINERAL VEINS.
•
329
touch it, or these parts might be separated from each other, leaving between
them open spaces, which were afterwards filled up, in part at least, with
different mineral substances. The greater part of these grand events belong
to that part of subterranean natural history which can only be elucidated by
a consideration of the facts which the Earth presents to our view, for all
these great revolutions took place at a period long before the globe became
habitable to the human species. But whether fissures and veins were actually
formed in the manner we have described or not, it is no less true that this
manner of representing their mode of formation and the relative situation
which they bear to one another in the mountain is the most simple way of
accounting for them. It explains the uniform law of their formation both in
a general and more particular manner, and consequently we shall admit it
as the real one. This hypothesis would be still more satisfactory to the
naturalist, if it were equally easy for him to conceive how a new mineral
substance could be formed in these fissures, of a nature different from the
rocks in which the veins occur.
“A rent, or interruption of the continuity of a rock, when it intersects the
strata, is named a fissure (gangkluft)."
Werner then remarks that the direction and position of veins may
differ more or less from that of the beds of the rock in which they occur.
He discusses the problem that mineral substances are of a different nature
from those of which the mountain in which they occur is formed.
We find him again treating of the same subject. In continuation he says:-
"It is difficult to conceive how rents and openings of considerable size
can be produced without some portion of the adjoining rock suffering
such a strain as would form lateral chinks, so that the principal rent should
terminate in several smaller ones. When these smaller rents are filled with
the same matter as the principal vein, they are said to be branches of the
principal vein. In this case the vein is said to ramify or divide into
branches. The portion of rock contained between these branches is for the
most part of a wedge shape; in such cases the included mass is called a
wedge. When the branches run for any length in the same direction with
the main trunk they are called accompanying branches.
"It sometimes happens that when a vein is formed in a stratified moun-
tain, the vein not only traverses, but also deranges a stratum; that is to
say, one of the two parts of the intersected stratum changes its position,
being elevated or depressed in relation to the other strata. In this case the
strata are said to have shifted; the vein which produces this effect is called
(wechsel) shifter."
Werner calls this a "luminous, instructive, and satisfactory view;" and
he concludes his remarks on Von Oppel by quoting the following geognostic
observations, which, he says, "are extremely interesting and useful in
practice":-
'In the hollows and valleys of mountains of a moderate height the veins
for the most part follow the direction of the valleys.
“When a vein has been cut or deranged by a visible rent it is again
met with in following the direction of this last, on the supposition that when
the parts of a vein are thus cut they are mostly separated from each other."
330
[BOOK II.
THE FORMATION OF DEPOSITS.
Werner then gives the names of Lazarus Erkern and Modestin Feachsen,
who have written useful works on the chemistry of the subject and on assay-
ing, and Gellert, who has written a treatise on the same subject. Lower
Saxony has produced Cramer, and Sweden Scheffer and Bergman and the
Aulic counsellor Gmelin, who have treated the same question very learnedly.
He remarks: "The science of subterranean geometry was formed by
Agricola, Rösler, Weidler, and Baier successively; but brought to per-
fection by Oppel, Kästner, and Sheidhauer. The most recent work on
subterranean geometry is that of Professor Lempe."
Lehmann expresses his opinion that rents are open fissures, and veins are
fissures filled in. He says the veins which we find in mines appear to be
only the branches and shoots of an immense trunk, which is placed at a pro-
digious depth in the bowels of the earth; but in consequence of its great
depth we have not yet been able to reach the trunk. The large veins are
the principal branches, and the slender ones its inferior twigs.* After this
Lehmann need not be quoted any further.
Wallerius, who wrote in 1768, had a very imperfect idea of the nature of
mineral veins.†
Delius published in 1770 a short treatise on rocks and veins. He con-
siders veins to be rents formed by the drying of the rocks, which have since
been filled up. His ideas are mainly borrowed from Agricola.‡
Bergman, in his "Physical Geography," merely says miners apply the
name of vein to rents that are filled up, and consequently are shut—the words
kluft and schial express nearly the same thing; but what is called trum is
a small rent quite shut, whose walls converging form a wedge.§
Von Charpentier published in 1773 his "Mineralogical Geography of
Saxony." He objects very strongly to the theory which considers veins to
have been rents which have been filled up by mineral substances.||
Pryce, in 1778,¶ speaks of lodes as fissures in rocks occasioned by so many
shocks and subsidences, adding "that the strata were not unfooted, shaken,
or brought to fall once only, or twice, but several times. He observes also
that mechanical effects are produced by cross courses: "Because cross gossans
or cross flukans run through all veins of opposite directions, without the least
interruption from them, it seems reasonable to conclude that the east and
west veins were antecedent to the cross veins."
Baumer,** counsellor of mines, Leipsic, 1799, remarks: "Veins differ from
the strata in which they occur both with respect to their form and sub-
stance. Their formation is posterior to the rock. It appears from many
observations that they have been formed under the ancient sea, for their
upper extremity is often covered with several beds of schistus; and in
* D. Joh. Gottl. Lehmann's "Abhandlung von den Metalmüttern und der Erzeugung der metalle.”
8vo. Berlin: 1753.
† Joh. Gollsch. Wallerii, "Elementa Metallurgia Speciatim Chemica." Holmiæ: 1768. And
"De venis Metallicis."
"Abhandlung von den Ursprunge der Gebirge und der darinne befindlichen Erzadern, oder der
sagenanten Gänge und Klüfte; ingleichen von der vererzung der Metalle und insondereit des Goldes.”
Edited by Professor Schreiber.
§ Sir Torbern Bergman's "Physicalische Beschreibung der Erdkugel." Greiswald: 1791.
Further illustrated in his "Beobachtungen über die Lagerslädle der Erze." Leipzig: 1799.
Mineralogia Cornubiensis," p. 82.
¶ "
** Jo. Guil. Baumer, "Fundamenta Geographiæ et Hydrographie Subterranea." 8vo. Giessæ: 1779.
1
CHAP. III.]
WERNER'S NEW THEORY OF VEINS.
331
cavities in the substance of the vein we frequently meet with marine
animals in a petrified state."
Gerhard, in his Essay,* supposes veins to have been originally rents in
mountains which were afterwards filled up with mineral substances. Many
causes may have led to this. Minerals, he supposes, may have originally
existed in the rocks, and that they had been carried in a fluid state into
the fissures, &c., where we now find them.
Von Trebra is quoted by Werner, but as he deals with putrefaction and
fermentation, as causes of mineral formations, we need only refer thus
briefly to him.
Lieutenant Lasius,† in his work on Mountains, considers veins as rents
in the rocks, which have been filled in by water. He thinks nature has
given "minute metallic seeds," which by water have in one place been
converted into lead, in another into silver, or any of the metals or semi-
metals.
In 1791, Abraham Gottlob Werner, professor of mineralogy at Freyberg,
published his “New Theory of the Formation of Veins, with its Application
to the Art of working Mines." This was translated into English in 1809
by Charles Anderson, M.D. His theory of mineral veins has claimed
the attention of the thinking miners and men of science. Being a Counsellor
of the Mines of Saxony and Professor of Mineralogy, he had remarkable
opportunities for the examination of lodes, and the art of working mines at
Freyberg. He was evidently a man whose powers of observation were of
the highest character, and whose reflective faculties had been trained in a
truly philosophical school. It therefore becomes necessary to give more
than ordinary attention to his "New Theory of Veins.”
In the commencement of his elucidation of his so-called "New Theory,"
Werner quotes, after a brief allusion to some classic authors, Agricola,
who, in his "De Ortu et Causis Subterraneorum," says the rents and fissures
in which veins are found he supposes to have been formed partly at the
same time with the rocks themselves, and partly afterwards by the waters
penetrating them.
He then refers to Balthasar Räsler (Rösler). In his "Speculum Metal-
lurgia” he writes: "A fissure is a chink or gap which cuts and divides
the rock, and is like the crack in a vessel which allows water to flow through
it. Some of these fissures are long and wide, others short and narrow. What
constitutes the vein itself, and what it contains enclosed within it and forms
its principal part, is either the materials in which the mineral is found,
or metallic matter, or a kind of clay, quartz, spar, &c. . . The rock
sometimes contains druses; these are hollow cavities of a round or oblong
form and different sizes, which are commonly found in veins. Sometimes
the veins are full of these cavities, when they are said to be open. A vein
is said to be shut when it is quite filled up either with stony or metallic
matter. The druses are often filled up with clay or other matter. In that
case the vein is said to be closed, although it contains druses."
* Carl Abraham Gerhard's "Versuch einer geschichte des Mineral-Reich." Berlin: 1781.
† George Otto Sigismund Lasius, "Beobachtungen über die Harzgebirge, als ein Beitrag zur
Mineralogischen Naturkunde." Hanover: 1797.
332
[BOOK II.
THE FORMATION OF DEPOSITS.
The "New Theory" starts by giving definitions to two forms of mineral
deposits, Veins and Stockwerke.
Veins are rents which have been formed in mountains, and have been
afterwards filled up by mineral matter more or less of the nature of the rocks.
The Swedish mineralogists give the name of gangar to mineral repositories
in general. Veins properly so called they name skiælard (consult "Wallerii
Elementa Metallurgia ").
Stockwerke is a part of a rock of a greater or less extent, which is
penetrated and crossed in all directions by an almost innumerable quantity
of small veins.
True veins are thought to be originally, and of necessity, rents open in
their upper parts, which have been afterwards filled up from above. With the
causes producing those rents, after what has been already said, we need
not embarrass the reader.
Werner supposes the Slate and Sandstone rocks to have been produced by
precipitation, or in the humid way. If we understand him correctly, he
believed that the older rocks were subjected to the influences of air and water,
and thus disintegrated to an immense extent.
As the matter which was held suspended in the water, then flowing over
the surface, was gradually deposited-precipitated-on the igneous and
other rocks of an older age, these old rocks might have been fissured in the
process of cooling or drying. Then the mud of the waters would have filled
those fissures, and, as Werner thinks, "furnished and produced" the
substance of the veins.
Veins have been produced at very different times, and the relative age of
each can be easily assigned, thus—
(a.) Every vein which intersects another is newer than the vein
traversed. "The oldest vein is traversed by all those that are of a
posterior formation, and the newer veins always cross those that are
older.
Werner's own expression is: "By the crossing and intersecting of veins
the antiquity or relative age of each can be easily assigned. Every vein
which intersects another is newer than the one traversed, and is of later
formation than all those which it traverses. This crossing of veins is
of great importance, and deserves to be kept in remembrance by all who
wish to become acquainted with the study of veins; yet, till lately, it has
always escaped the observation of mineralogists.
Sopwith, quoting some "highly intelligent miners" in opposition to this
theory, says: "Cross veins I suppose to be fissures which were first formed,
and this easily accounts for the shifting of the east and west veins by suppos-
ing the force which created these second veins not strong enough to carry
them directly through the cross vein, but yet sufficient to continue the fissure
in the next weakest place. The Wernerian system seems absurd, because if
the east and west veins were first formed it would require the whole strata
to be shifted along with them, which alone would carry them off their point;
besides which, while one vein is carried off its point northward, another lying
near it is removed southward, whereas if a longitudinal shift of the strata
occurred at the formation of the cross vein all the other veins would
CHAP. III.]
DEFINITIONS OF MINERAL VEINS.
333
be removed in one direction. Nor," says Sopwith, "is this general rule of
cross veins intersecting east and west veins without exception, as Scale-
burn cross vein at Nenthead, in Alston Moor, is carried eighty feet off its
point by an east and west vein.”
Werner visited the mines of Cornwall with Mr. Carne, who was, there-
fore, led to a general acceptance of his hypothesis in the following words:-
"When two veins cross, one of them, without suffering any derangement or
interruption, traverses the other; this last is interrupted and cut across
through its whole thickness by the former. The first of these is said to
traverse the other, and the latter to be traversed by the former. The vein
which crosses another is of newer, whilst the last is of an older formation.”
(b.) The middle part of veins is commonly of later formation than that
portion which is nearer their walls, and what we find in the upper
part of a vein is newer than what we meet with in the lower part.
(c.) In a specimen composed of different minerals the super-imposed
portion is always of a newer formation than that on which it rests.
Werner, in defining mineral veins, follows Rösler very closely. "The
cavities which veins now occupy are, he says, ore rents which have been
formed in the rocks; these cavities were at first fissures, gaps, and rents, of
various sizes, with openings in their upper parts." In support of this theory
he brings forward nine proofs, which are as follows:-
I.—“When the mass of materials of which the rocks were formed
by precipitation in the humid way, and which was at first soft and movable,
began to sink and dry, fissures must of necessity have been formed, chiefly
in those places where mountain chains and high land existed."
2.-" Rents and fissures are still forming from time to time in mountains,
which have a close resemblance to those spaces now occupied by veins. The
fissures are formed mostly in rainy seasons, or by earthquakes."
3.—“ Veins, in respect of their form, situation, and position, bear a strong
resemblance to rents and fissures which are formed in rocks and in the Earth ;
that is to say, both have the same tabular figure, and the deviations which
they make from their general direction are few in number and very incon-
siderable."
4.—“No one can doubt that the small oblong cavities (gang-klüfte)
which are found in great abundance in rocks are in reality small rents
or chinks. Now there exists an uninterrupted chain, from the narrowest
fissure to the greatest vein, so that it is impossible to draw a line of distinc-
tion between what is actually to be considered as a true rent or fissure and
that which is a vein without being a fissure. We sometimes meet with
a small vein which does not exceed the thickness of a straw completely
filled with mineral matter; and at other times we find rents of three or four
inches wide, which are perfectly empty."
5.-" Are not druses and the small crystals which line their walls only
certain parts of a vein which have not yet been filled up, and consequently
the remains of the space in which the vein has been formed?"
6.-" A consideration of the materials of which many veins are composed
proves in so incontestable a manner that veins were originally empty
fissures, that no doubt can now remain on the subject. Certain veins are
334
[BOOK II.
THE FORMATION OF DEPOSITS.
filled with rolled matter, or water-borne stones; fragments of adjacent rocks
are often found in the middle of the vein; débris of the substance of a vein
is sometimes found in considerable quantities in the same vein; the occur-
rence of petrifaction in veins-rock-salt and coal substances of very recent
formation are found in veins—the occurrence of materials of mountain rocks
in veins—all these go to show that they were originally open fissures.”
7.-"The mode assigned for the formation of the spaces now occupied by
veins is still further demonstrated by the relation which veins have to one
another: as their intersecting one another, their shifting one another, their
splitting one another into branches, their joining and accompanying one
another, their cutting off one another. All these peculiarities are produced
by the effects of a new fissure upon one that is older.”
8.—“ The relation which veins bear to the rocks and beds in which they
occur, or the manner in which they are found in them, proves still further
that they have been fissures."
9.-"If we examine with attention the interior structure of veins that are
composed of different kinds of minerals we perceive them to have been
originally open fissures which have been afterwards filled by degrees. Such
veins are composed of beds arranged in a direction parallel to their sides;
their crystallizations show these beds to have been deposited successively on
each other, and that those next the wall have been first formed."
C. Bernhard Cotta is one of the most celebrated of the German geologists
who have seriously dealt with the subject of the formation of ore-veins.*
Professor Cotta's memoir is usually thought to be one of the completest
expositions of the hypothesis with which it deals.
It appears desirable
that a somewhat careful abstract of this contribution to science should be
placed before the readers.
The observed relations between crystalline and eruptive rocks and metal-
liferous deposits have been already dealt with. It is nearly a constant fact
that all metalliferous deposits are always found connected with those geolo-
gical formations and those intrusive rocks which are generally referred to
igneous action. The first difficulty with which Cotta grappled is in the
endeavour to answer the question, Whence are the metalliferous contents of
mineral veins derived?
Three views have been adopted by different schools. One argues the ore
deposits have been derived from above; another insists upon it that all
metalliferous matter has been derived from some subterranean source—some
suppose by the agency of hot springs, others think by vapour jets charged
with metallic matter-while others would refer them directly to igneous
action, such as produces Granite veins and Elvan courses, &c.
Professor Cotta leans to the hypothesis that these deposits are produced
by segregation from the enclosing rock. This hypothesis-theory it is not—
deserves the closest consideration, and strong evidence can be brought
forward in support of it. It does not, however, account for the original
*Gangstudien," vol. i. p. 85. By C. Bernhard Cotta, Professor of Geognosy at the Mining Academy
of Freyberg. The works of C. Bernhard Cotta range from 1832 to 1877. His book on Mineral Deposits
was published in Freyberg in 1855. This work, "Die Lehre von den Erzlagerstätten," has been trans-
lated into English by Frederick Prime, and published in New York in 1870.
CHAP. III.]
BERNHARD COTTA'S HYPOTHESIS.
335
source of the metals-by what agency or physical power were the metals
introduced into the rocks from which they are supposed to be derived. It
fails to explain the abundant distribution of the metallic ores in one dis-
trict-for example, Cornwall-while in other districts, in the same character
of rock—in Leicestershire, for instance—they are absent.
Metallic ores generally occur in veins which take a given direction and
are of a definite size, the direction being in many districts associated with
characteristic ores. But the direction of mineral lodes does not in separate
districts give rise to the same kinds of deposit. Metallic deposits again are
not always found in veins; they often occur in beds, in nodules, and in
"stocks," irregular and indefinite masses. With the veins of Granite, or
Elvan, or Greenstone we have no concern; the veins producing the useful
metals—and these are generally fissured veins-are the only ones with which
we have to deal.
The formation of mineral veins is intimately connected with the forma-
tion, or metamorphism of certain rocks, and is a certain effect of special
geological causes. Particular species of ores are found in veins with very
varied combinations and under very diverse circumstances. With the
exception of iron-stone, mineral veins are universally found in the older
rocks, more especially in crystalline schists, in the eruptive and grauwacke
formations, but rarely in the newer sedimentary rocks; their occurrence is
equally rare in trachytic, basaltic, or phonolitic rocks. It is not supposed
that the massive rocks are the original bearers of the contents of ore-veins.
Many metalliferous deposits are undoubtedly due to segregation, but it
completely fails to account for the abundant distribution of the metallic
ores in some districts, while in others, in the same class of rocks, there are
no ore-veins or deposits to be found. The theory of metallic ores from
beneath has been suggested by many, but this too is met with contradictions
on every side. The near relation between the crystalline and eruptive rocks
and metalliferous deposits is universally believed in, because universally
observed, although even here are exceptions; but it has never been accounted
for in anything like a satisfactory manner. Metallic ores occur in abundance
in veins of a definite size and direction; the direction being constantly asso-
ciated in certain districts with characteristic ores. Cotta holds that metals
originate below out of the eruptive rocks, which, accepting the theory of gradual
refrigeration, are assumed to form portions of the original fluid nucleus.
There is objection to this, for although metallic ores are generally found in
connection with eruptive rocks, particularly near their junction, they seldom
occur in any quantity in them; and in cases where they have been so found
they are only rich near the surface, and the ore totally fails on sinking deeper
into the crystalline rocks. One would naturally think that if the ore came
from below it would be richer the deeper we penetrated the Earth's crust, but
the result of Cornish mining proves this to be incorrect, for in Granite the
ore generally becomes poorer the deeper the miner works. Cotta meets this
objection by saying that ore should only be sought where a rapid cooling of the
eruptive mass has occurred, and as this rapid cooling is found to have occurred
in vein-masses, such as porphyry or Elvan, and in small "stock masses,"
or on the contact and edge surface of the larger masses, his theory so far
336
[BOOK II.
THE FORMATION OF DEPOSITS.
holds good, for it is in just such positions that the ore-deposits are most
abundant.
The contents of the vein varies with its direction; this, he says, is
"nothing else than the products of unequal stadii of cooling of one and the
same vein-forming process." The upheaval of the Earth's crust must have
produced fissures in nearly parallel groups in the same locality at the same
time; these, one can imagine, would be filled with such minerals as were
passing in solution from the eruptive rock through the veins, and were
capable of being precipitated, at the then state of the temperature and
pressure. If we suppose a subsequent change in the direction of the ele-
vating force, we should then have a new set of parallel fissures, but with a
different direction. These would in their turn become filled with such
minerals as were then in circulation through the vein region, and were
capable of being deposited at the temperature existing at that period. We
may imagine a long lapse of time between the two fissure groups, then one
might suppose there would be a great alteration in temperature, and another
mineral would be deposited; although it might perhaps have been flowing
in solution at the time of the first upheaval it could not be deposited, the
higher temperature having kept it in a state of solution. The older ores are
not found in the newer fissures for the like reason, the temperature had
gradually become too low to enable the circulating fluid to hold them in
solution. There is a strong analogy found to exist between the relative age
and general characteristics of veins in countries widely apart, due to the
analogous consequences of local eruptions. Cotta found in the Freyberg veins
proofs of his general theory; the older veins are generally massive, while the
newer ones are always banded or layer-like in form. It is possible that the
newer veins were formed by infiltration, but that theory would not hold good
for all ore-veins; tin ore is found in some places where it may be due to
infiltration, but in others this would appear to be an impossible origin.
Fournet generally follows Werner in his hypotheses, but he differs from
him as to the extreme regularity which is sometimes noticed in veins;
and remarks: "When, for example, the veins contain fragments of the
adjacent rock imbedded in their mass, the ore in preference attaches itself
around them, enveloping them in a bed of greater or less thickness."* He
notices that this fact is frequent in the mines of the Hartz, whence the sul-
phide of lead obtains the name of ringertz, or ring ore; but states, however,
that the veins of Pontgibaud give evidence of successive openings.
M. Albert Louis Necker read, in 1833, before the Geological Society
of London, a paper on Metalliferous Deposits, of which the following is
a carefully made abstract.†
The doctrine of the sublimation of the metalliferous contents of veins
from igneous matter occurred to the author twelve years before from observing
the deposition of specular iron on the cooled lateral edges of a stream of
lava flowing down the side of Vesuvius, and he was induced from that cir-
* (
Études sur les Dépôts Métallifères.”
†M. Albert Louis Necker, "An Attempt to bring under Geological Laws the relative Position of
Metalliferous Deposits with regard to the Rock Formations of which the Crust of the Earth is formed."
("Transactions of the Geological Society of London." Second Series, vol. iii. p. 494. 1835.)
CHAP. III.]
THE INFLUENCE OF UNSTRATIFIED ROCKS.
337
cumstance to institute a series of inquiries. In further prosecution of which
he proposes in the memoir the following questions:-
1.—Is there near each of the known metalliferous deposits any unstratified
rock?
2.—If none is to be found in the immediate vicinity of such deposits, is
there no evidence, derived from the geological constitution of the district,
which would lead to the belief that an unstratified rock may extend under
the metalliferous district, and at no great distance from the surface of the
country?
3.-Do metalliferous deposits exist entirely disconnected from unstratified
rock?
With respect to the first of these questions the author endeavours to
show-by copious references to works on England, Scotland, Ireland, Norway,
France, Germany, Hungary, the Southern Alps, Russia, and the northern
shore of the Black Sea-that the great mining districts of all these countries
are immediately connected with unstratified rocks, and in further support
of this solution of the first question, he mentions the metalliferous porphyries
of Mexico and the auriferous Granites of the Orinoco, but he observes that
his knowledge of the mining countries of South America is not sufficient to
enable him to state their general geological connections.*
*
With reference to the second question, the probable associations of
metallic veins with unstratified rocks-though the latter are not visible in
the immediate neighbourhood of the former-the author gives a section of
the country between Valorsine and Servoz, and points out the probable
extension of the Granite of Valorsine under the Arguelles Rouges and
Breven-composed of protogine, chlorite, and talcose schists-to the imme-
diate vicinity of the mines of Servoz, which are situated in the latter forma-
tion. He also refers to the metallic deposits of Wanlock Head, the Lead
Hills, and of Northumberland, and to several districts in Europe, all of which
occur in districts where unstratified rocks are known to exist. It will be
seen, by referring to the chapter devoted to rocks, that the mines in Scotland
and Northumberland do occur in stratified rocks, but they are frequently
penetrated by rocks of igneous origin, and consequently unstratified.
In reply to the third question, the author enumerates the mines of the
Netherlands, the copper slate of Mansfield and Thuringia, &c. &c., the
veins of galena in the Inferior Oolite near Frome, in the Magnesian
Limestone of Durham, and the Mountain Limestone generally.
The author next gives, as an illustration, a sketch of several countries
and of the western part of England. He shows that metallic deposits
are totally wanting in the district extending from the foot of the Alps
across the valley of Lake Leman, the Jura chain, and the plains of Franche
Comte and Burgundy, and in the Oolitic and tertiary formations of the
north-west of France. He also states-which has been previously pointed
out—that in the tertiary and secondary formations of England, as far as
Devonshire, there are no metalliferous deposits, but that as soon as the
unstratified rocks recommence metallic veins reappear.
*Surely the Clay-Slate-killas-of Cornwall and the Devonian rocks must be regarded as stratified
rocks. These may be considered as essentially metalliferous rocks.
Ꮓ
338
[BOOK II.
THE FORMATION OF DEPOSITS.
Lastly, M. Necker states, that ores are more abundant in Granite, certain
Porphyries, Syenites, Amygdaloids, and Trap-which he calls underlying
unstratified rocks-than in the newer Dolorites, Porphyrites, and the true
volcanic formations, which he distinguishes by the term of "underlying
stratified rocks;" and he alludes to the assistance which the practical miner
would derive from attending to this distinction, as well as to the connection
of igneous with metalliferous formations.
Mr. R. W. Fox, of Falmouth, who had, for a considerable portion of his
long and well-spent life, directed his attention to the subterranean phenomena
-which he had the best possible opportunity of studying-in the Cornish
mines-published an elaborate paper on mineral veins.* This memoir is
of so high a character, it shows in every part so fully the operation of the
mind of the philosopher, that it is to be regretted we are not enabled to
reproduce it. Compelled, however, by the extent of the subject and the
limits of space, we must confine attention to the "Recapitulation." It may
be allowable to state that all the leading points of the inquiry are very
clearly enunciated in it.
Mr. Fox thus summarises his views:-
"1. That, admitting the origin of mineral veins to have been derived
from fissures in the Earth, there is reason to believe that the latter may have
been produced by different causes, and at various intervals; also that many
of them have been enlarged from time to time.
"2.—That the accumulation of mineral deposits in such fissures has
been likewise progressive, and that the evidences afforded by the resem-
blance of the vein-stones to the several enclosing rocks, and the arrange-
ment and subdivisions of the contents of veins, are decidedly in favour of
both these conclusions, independently of other arguments based on mechanical
principles.
"3.-That the phenomena of veins seem to indicate that many of the
fissures penetrate to a great depth, and into regions of very high tem-
perature; and that, consequently, the water which they contained must
have circulated upwards, and downwards, with greater or less rapidity.
<< 4.—That since the solvent power of water seems to increase in some
ratio to the augmentation of its temperature, it is obvious that it would tend
to dissolve some substances at a great depth, which it would deposit more
or less in the course of its ascent through cooler portions of water; and also
in consequence of its partial evaporation on reaching the surface.
<<
5.—That a part of the earthy contents of veins, and more especially
silica or quartz, was apparently accumulated in this manner, and usually
combined more or less with matter otherwise deposited.
"6.-That rocks, clay, &c., containing different saline solutions and
metalliferous substances, in contact with water, charged in many instances.
with other salts, were calculated to produce electrical action; and that this
action was probably much increased by the circulation of the water and
differences of temperature; but more particularly by the existence of com-
pressed and heated water, metallic bodies, &c., at or near the bottom of the
fissures.
*Transactions of the Royal Cornwall Polytechnic Society," vol. i.
CHAP. III.]
ROBERT WERE FOX ON MINERAL VEINS.
339
"7.-That, since the water in the fissures containing metallic or earthy
salts was a conductor of electricity, especially when heated, and in a very
superior degree to the rocks themselves, it is evident that, in conformity
with the laws of electro-magnetism, the currents of electricity would, if not
otherwise controlled, pass towards the west, through such fissures as were
most nearly at right angles to the magnetic meridian at the time.
“8.—That the more soluble metallic and earthy salts may have been
decomposed by the agency of such electric currents, and the bases been
thereby determined in most instances towards the electro-negative pole, or
rock; that tin, however, under these circumstances is only partly deposited
at the electro-negative pole, and partly at the electro-positive pole, in the
state of a peroxide; and that the properties of this metal seem to bear on
its positions in the lodes; and especially to explain why copper is sometimes
found with it, and sometimes distinctly separated from it.
"9.-That the position of one rock with respect to another, or to a series
of other rocks, may, as well as their relative saline or metallic contents,
temperature, &c., have had a decided influence on the deposition of minerals.
on them by electrical agency, so that a given rock may have been electro-
positive in one situation, and electro-negative in another, in regard to other
neighbouring rocks, as this is quite consistent with voltaic phenomena.
66
10.—That the evolution of sulphuretted hydrogen and the tendency of
some metals when in solution to absorb oxygen, and become insoluble, may
in many instances have interfered with the regular arrangement of the
metals, such as electricity would have effected, and that hence many
anomalies may have arisen, especially in relation to tin.
"II. That the electrical reaction of the different metalliferous bodies
and of masses of ore on each other, after their deposition in the fissures,
may have corrected such anomalies, in some instances, and that they may
have given rise to them in others, by changing the direction of the electric
currents, and thus modifying the relative positions of the deposits; and that
the pseudomorphous crystals of various descriptions, as well as other
phenomena observable in mines, fully prove that some such secondary action
must have taken place.
<<
12.—That cross veins may have been filled mechanically or by the
decomposition of silica from a state of solution, or by both these means,
and that the striated and radiated structure of quartz may be owing to the
tendency of electricity under ordinary circumstances, to pass transversely
rather than longitudinally, through north and south veins.
"13.—That, assuming the proofs of the progressive opening and filling
of lodes and cross veins to be admitted, it seems to follow that many inter-
sections may have been caused by the more ready accumulation of clay and
other mechanical matter, and even of silica from its solution, than of the
more slowly formed metalliferous or crystalline deposits.
(C
14. That the frequent occurrence of a mass of ore in that part of
a lode which is intersected by a cross vein, and also of small branches of ore
from a dislocated part of a lode on one side of a cross vein, without there
being corresponding veins near the other part of the lode on the opposite
side of the cross vein, afford strong evidence of the deposition of the ore in
Z 2
340
[BOOK II.
THE FORMATION OF DEPOSITS.
such cases after the intersection took place; and that it was accumulated in
the east and west vein rather than in the north and south one by the influence
of electro-magnetism.
"15.—That the small veins of copper and tin ore which are often found
in cross veins, between the dislocated parts of lodes, and the frequent occur-
rence of more considerable, and yet for the most part very limited, quantities
of these ores in the former, in the immediate vicinity of intersections, are
additional arguments in favour of the operation of the same definite agency.
"16. That the secondary fissures, resulting from the cracking off of
larger or smaller masses of the hanging sides of veins, may have been
partly filled, in many instances, by the electric action of different portions of
ore on each other, and that secondary lodes may have been formed at right
angles to parallel east and west lodes, in consequence of the reciprocal
action of the latter.
"17.-That many other phenomena of mineral veins, including those of
a mechanical character, such as the occurrence of horses, heaves, &c., appear
to be capable of satisfactory explanation on the principles which have been
laid down.”
Imperfect, and limited, as is our acquaintance with mineral veins, enough
is known to excite our admiration in the order and fitness which prevail
amongst them. We observe that many of the most useful metals are the
most abundant; and the fact that they are generally confined to certain veins,
and to portions of them only, is perhaps of greater import than we might
at first suppose; for had they been disseminated in the strata, or even
dispersed throughout all mineral veins, the labour required to obtain them
would have rendered them practically useless; or had they, on the other
hand, been much more concentrated, their rapid exhaustion might entail
incalculable injury on future generations.
Again, we remark that few metals are found in a native state, and those
very sparingly; were it otherwise, there is good reason to believe that their
electric action and reaction would have been so energetic, that some of the
electro-positive metals could not have been permanently deposited. Had
the metals generally existed in combination with oxygen or acids, their
electric action would have been reduced to a minimurn quantity; in which
case many metallic and other solutions might, from being but partially
decomposed, have found their way to the surface and impregnated the springs
with their deleterious qualities. Sulphur appears to be the only component
which enables metals to effect all the required conditions, and this proves to
be the combination in which they most frequently occur. It has already been
mentioned that such of the metallic sulphides as conduct electricity are
highly electro-negative, and that their reciprocal action in most instances
is so nearly in equilibrio as to prevent considerable changes; neverthe-
less they seem to possess sufficient electric activity to act upon other bodies,
and to decompose saline solutions which may be exposed to their influence;
and who knows how important such electrical filtration of the ascending
water may be to organic existence at the surface of the earth?
Some of the cross courses appear to be channels for conducting the water
between different lodes; and the flucan veins, by occasionally intercepting
CHAP. III.]
THE OPERATION OF OSMOSE FORCE.
341
it, tend to prevent the too great drainage of the land which would otherwise
attend mining operations, whilst at the same time they enable the miner to
prosecute his labour underground to a much greater depth than would
otherwise have been practicable.
Considering the nature and arrangements of mineral veins under the
surface, it can scarcely be doubted that the endosmose and exosmose processes
must prevail, more or less, within the Earth, and tend to cause differences
in the water level on the opposite sides of flucan courses. This influence-as
has been before remarked-may be sometimes exerted in the same direction
through a series of parallel clay veins, so as to produce successive elevations
of the water, and thus affect the relative heights of springs. There are good
grounds for believing that some of the most occult phenomena connected
with respiration, and with the causes active in producing the animal and
vegetable secretions, depend on the same process, which is itself apparently
a modified form of electrical agency.
This at least is certain, that the action of electricity is not confined to
the surface of the Earth; and it is more than probable that it is inherent in
all matter in some modified form; so that, should the Hand that produced it
suspend its operation but for one moment, animal and vegetable life would
be universally extinguished and the mineral world become again chaotic.
The property which water possesses, in common with all other fluids, to
ascend when heated, and to the influence of this property, in conjunction
with the high temperature of the interior of the Earth, in the filling of
fissures with mineral deposits, has been already alluded to.
Thermal springs seem to be a result of similar causes, and it is un-
necessary to enlarge on their uses to mankind. Were it not for this law
of fluids, the great ocean-currents which circulate between the polar and
equatorial regions,-tending to equalise the temperature of the Earth's sur-
face,—would cease to flow, and the atmosphere would be comparatively
stagnant and unfit for respiration.
Evidences might be multiplied, almost without limit, to show the perfect
adaptation of simple general laws to every possible case in the whole
circle of creation. We can, however, detect their existence only by their
effects, for our perceptions are far too limited, and our comprehensions
too feeble, to understand the elementary constitution even of the simplest
form of matter. There is, nevertheless, in all nature a harmony of parts,
and a consistency of operation, calculated to excite our reverence and grati-
tude towards her Almighty Author, whose infinite foreknowledge and good-
ness thus forcibly manifest themselves in the perfect adaptation of physical
laws to every existing circumstance.
Amongst writers the most deserving of attention on this interesting
question must be named-
William Jory Henwood, whose "Metalliferous Deposits of Cornwall
and Devon" contains a larger number of facts-the result of personal
observation-than are to be found in any work in any language.
Westgarth Forster, in his "Treatise on a Section of the Strata," pub-
lished in 1809, gives valuable information on the mineral veins of
the northern counties. A new edition has just been published (1883).
342
[BOOK II.
THE FORMATION OF DEPOSITS.
Farey, in his "Derbyshire," gives useful information relative to the
phenomena of the lead mines of Derbyshire (1811).
John Williams, in his "Natural History of the Mineral Kingdom
(1789) and other works, describes the peculiarities of several sepa-
rate localities.
Joseph Fournet, in 1834, published his "Études sur les Dépôts
Métallifères," which contains important observations.
Sir Henry T. de la Beche, in his "Report of the Geology of Cornwall,
Devon, and West Somerset," published in 1839, describes very fully
the mineral veins and faults of the district which he surveyed.
In addition to these, it appears necessary to refer to the work of J. D.
Whitney, of the United States,* who has been long connected with the
American Mineral Survey. He defines a vein-as a geological and mining
term—to be “an aggregation of mineral matter of indefinite length and
breadth, and of comparatively small thickness, differing in character from
'and posterior in formation to the rocks which enclose it." Following Cotta,
Whitney divides mineral veins into veins of sedimentary origin, veins of
attrition,—veins of infiltration or stalactitic veins,—plutonic veins,—segregated
veins, and metalliferous veins proper. He refers to the several hypotheses
which have been promulgated, and remarks upon them as follows:-
I.
"1. The veins originated contemporaneously with the rock in which
they are contained, and are, so to speak, a mere accidental phenomenon, not
governed by any fixed laws of formation. This theory may be dismissed at
once, as entirely at variance with all the facts, as unworthy of consideration.”
(That some vein formations are contemporaneous with the formation
of the rock-produced probably during the consolidation thereof-many
examples will prove.)
"2.-Veins have originated in the filling of fissures by injection of
metallic and mineral matter in a state of igneous fluidity from below..
Such phenomena, however, have only been observed in isolated cases, while
usually the appearance of the walls, and the distribution of the mineral
matter and ore between them, in true metallic veins, is such as to make this
hypothesis of their formation entirely untenable."-(This is not a thoughtful
assertion. In Granitic veins and Elvan courses metallic ores are occasionally
found; these must, therefore, have been produced in a state of igneous fusion.)
"3.-The theory of formation by sublimation, according to which vein
fissures were filled by the volatilization of metallic matter from the great
centre of chemical action beneath, namely, the ignited interior of the Earth."
(That such may have been the origin of some metalliferous deposits, and
that this agency may have contributed in some degree to the filling of veins,
cannot be denied.)
“4.—The theory proposed by Werner presupposes a chemical solution
covering the region in which the veins are found. . . . . In the sense in
which this mode of formation was understood by Werner, but little import-
ance can be attached to it.
"5.—The Theory of Lateral Secretion.-The main idea is that of a segre-
* "The Metallic Wealth of the United States described and compared with that of other Countries."
By J. D. Whitney. Philadelphia: 1854.
CHAP. III.]
WALLACE'S HYPOTHESIS ON LEAD LODES.
343
gation of the mineral and metalliferous particles from the adjoining rocks
in a state of chemical solution, and their deposition upon the sides of a
previously formed fissure under the influence of electro-chemical forces.'
(This view is directly connected with the electricity of mineral lodes, which
should be studied.)
""
Although Mr. Whitney's "Metallic Wealth" indicates an imperfect
generalization, it exhibits very superior powers of observation, and the
volume is a real contribution of value to every thoughtful miner.
Having stated the more important authorities upon whom reliance has
been placed for contributions as to the phenomena connected with the
formation of mineral deposits, and given a clear expression of their views,
a concise statement will presently be made from which it is hoped satisfactory
conclusions may be drawn.
A few words are demanded on the views entertained by Mr. W. Wallace,
who, in 1861, produced an important work on the Alston Moor district,
based on an intimate knowledge of the mines of that locality, in which
he put forth some original thoughts on the laws regulating the mineral
deposits. From that work-and from correspondence with its author-the
following notes on the conditions connected with the deposit of lead, &c., in
the carboniferous rocks in the north of England have been compiled.*
1. The carboniferous rocks in which lead is found may be separated into
two groups, those above the Great Limestone inclusive, and those below it.
In Alston Moor the highly metalliferous portion is about 420 feet in thick-
ness; this portion comprehends all the strata between the top of the
Slate sills and the bottom of the Great Limestone. The shale beds lying
between each stratum, however, rarely contain lead ore. The less metal-
liferous portion comprehends all the rocks below the Great Limestone, the
Tynebottom Limestone, under conditions, excepted.
2. In both class of rocks large portions of the veins contain little or no
lead ore; but this is more especially the case in the less metalliferous portion.
3. The deposits of lead, in both class of rocks, are invariably connected
with conditions which are favourable to the descent of water from the surface
and its circulation in each stratum in a longitudinal direction in the vein.
The deposits of lead in the less metalliferous rocks are, with a few excep-
tions, poor, and extend a shorter distance from the surface than in the more
metalliferous rocks.
4. Water is prevented from descending into any particular stratum by the
great thickness of superincumbent strata. Under the summit of mountains
the veins contain little or no lead, even in the metalliferous Great Limestone
when it is lying at a great depth below the surface. Should rich deposits
be found in such a position they are due to a combination of causes which
rarely occur to the formation of valleys running in opposite directions on
each side of the mountain, to a rise of the strata at right angles to the vein,
to the opposite side of the mountain, the strata being broken up with inter-
secting fissures. These conditions cause the water, which sinks on one
side of the mountain, to flow to the other; and perhaps there are other
"The Laws which regulate the Deposition of Lead Ore in Veins, illustrated by the Mining
District of Alston Moor." By William Wallace.
344
[BOOK II.
THE FORMATION OF DEPOSITS.
especial conditions which have not come under observation. The descent
of water is also affected by the steepness of the sides of the mountains.
Where the sides are steep, water flows rapidly over the surface, and less of
it sinks into the rocks.
5. The descent and circulation of water to a great depth are occasionally
affected by the rise of strata, as shown in Fig. 47, the water descending
in fissures in highly inclined strata and ascending to the surface in the
vein. These conditions are connected with the rich lead deposits in
Stonecroft vein near Haydon Bridge.
6. The descent of water is affected by the dishing in of the side of the
mountain, and the quantity of water which circulates in the vein is pro-
portional to the extent of gathering ground in a higher situation than that
traversed by the vein. After its descent into the rocks it flows to the veins
in channels, or rather in weak intersecting cracks or fissures, which
frequently traverse the rich portion of veins in an oblique direction. In
consequence of the conditions connected with the descent of water the
richest deposits of lead are generally found at no great distance from
the outcropping of the containing rock. Veins which run on the sides
of a mountain in a direction nearly parallel with the valleys contain more
extensive deposits of lead than those which cross the valleys at right
angles.
7. The circulation of water in the veins is affected by the inclination of
the strata in the direction of the vein. The richest deposits are found in
that portion of strata which is the most elevated; for instance, on the side.
of a powerful cross vein (Fig. 50); thus:-
BARREN
CROSS VEIN
-RICH
Fig. 50.
-LESS RICH.
POOR.
The circulation of
water is depen-
dent upon an out-
let at a lower
level.
8. Under the
beds of the prin-
cipal rivers - not
those streams
which flow rapidly
down the sides of
the mountains-the water may sink, but it cannot circulate; consequently,
in the most metalliferous rocks, lead has only rarely been deposited even
at a moderate depth below the surface; generally the veins contain no lead.
At great depths not only lead but all other vein minerals are entirely
absent.
9. Near the surface the contents of veins are invariably in a state of
decomposition, the higher the elevation on the sides of the mountains the
greater is the amount of decomposition, unless the vein has been filled with
the insoluble sulphate of barytes. The carbonates of lead and zinc are
formed from the decomposition of the sulphides and the combination of
their oxides with carbonic acid.
10. The water that falls from the atmosphere contains from 6 to 8 per cent.
CHAP. III.] THE INFLUENCES OF AQUEOUS AGENCY.
345
of oxygen in solution. As the water descends the oxygen disappears in the
destructive oxidation of the rocks and contents of veins, &c. It would,
therefore, appear that until the absorption of the free oxygen from the water
is entirely effected, lead and the other accompanying vein minerals cannot be
deposited. It is also probable that lead is never deposited very near the
surface; though from subsequent denudation, greatly effected during the
glacial epoch, it is not unfrequently found in the clays and broken rock near
the surface. In some few instances the form of the surface has been greatly
altered since the deposit of ore; but generally, though the mountains have
been denuded, their outlines remain much the same.
11. That water does not lose its solvent power by the deprivation of its
free oxygen is evident from the enormous quantity of rock, chiefly Lime-
stone, which has in many places been dissolved, and the caverns formed,
refilled with crystalline substances. It is probable that the dissolution of
the rock and the refilling were carried on at the same time, for it is certain
that, in many instances in the Westmoreland mines, the space could not
possibly have remained open after the disappearance of the Limestone, but
would have been filled with the soft overlying shale. Many of these crystal-
line substances are totally different from the rock which once filled the space
they now occupy-carbonates of lime and iron, fluorides of lime, sulphides
of iron, lead, and zinc; and in the Westmoreland mines, sulphate of barytes
and sulphide of lead, with scarcely any other kind of mineral. The oxides,
however, are not there; even the carbonate of iron, so easily converted into
an oxide, retains its pearly brightness. Where this mineral is found par-
tially changed into an oxide, a destructive agent has commenced its work.
But by what enchantment have these wonderful changes been effected in the
deep caverns of the Earth, so strangely different from any that are to be found
at the surface?
12. The sublimation of the metals and other foreign substances from
beneath is to use the words of Professor Whitney in reference to the lead
deposits of the Upper Mississippi-" an impossibility, absolute and entire."
Taking into consideration the facts connected with the metallic deposits, it
is evident that the only source from which they can be derived is the Lime-
stones and Sandstones forming the enclosing rocks, the laws of chemical
combinations being unknown. It is probable that sulphuretted hydrogen,
often present in the mines, is one of the chief agents. This opinion is
sanctioned by Professor Whitney; and it is probable that carbonic and
fluoric acids play important parts in the formation of minerals, the latter
particularly so, in the early stages of the process. Limestone which has not
been removed is frequently changed into a very hard substance by the
absorption of carbonic acid, and the loss of some of the calcium.
13. It is probable that deposits of lead and other minerals are being
formed and destroyed in different parts of a vein at the same time. The
metallic deposits must have shared the fate of the containing rocks which
once filled up the valleys. These processes of composition and destruction
have been in operation throughout periods of past time, the duration of
which we can form very little conception.
Notwithstanding the eminence of the authors named, as authorities on
346
[BOOK II.
THE FORMATION OF DEPOSITS.
the question of mineral lode formation, it must be admitted that their
hypotheses fail to carry to the mind of the careful observer that conviction
which must be established before any satisfactory theory can be adopted.
Among the hypotheses, we find that the following are put strongly
forward in explanation of the formation of mineral lodes. That is, accepting
the geological view of the formation of the fissures in which the metallic ores
are accumulated, they attempt to explain the process by which the contents
of these fissures are deposited.
(a.) Contemporaneous formation involves the idea of a mass of rock-matter
being produced containing metallic matter, or the mineralised ores in
mechanical mixture or in chemical combination with it, which as the rock
consolidates separates and forms veins, crystalline or otherwise, spreading
through the clayey, pasty rock. Metamorphic action has been referred to as
producing some effect. It is very doubtful what this may mean, as we find
mineral veins in Granite and in Slate, which have not undergone any such
change as metamorphism implies.
(b.) Segregation may take place from the mineral matter which exists
contemporaneously with the alumina, silica, or lime of the rock; or it may
be produced during the infiltration of liquid matter holding metallic salts in
solution, after the rock has partially consolidated, either by the action of heat
or the influence of time. Therefore segregation may be considered as a
phenomenon connected with contemporaneousness, or, as the result of
subsequent mutations.
An example of this may be obtained by placing in a slightly porous
cell of fine earthenware a solution of sulphate of copper.
This will pass
through the porous wall very slowly, and the water will be evaporated
from the exterior surface. During this action metallic copper will be left
in the pores of the cell, which, by increasing and crystallising, gradually
produces fine cracks filled with films of metallic copper. Another condition
may be mentioned under this head, although it involves the operation of
chemical action and surface force (may we not adopt, as a convenient
expression for this form of cohesive attraction, the term epipolism? The
word was employed to express some phenomena of light, but as this was
shown by Professor Stokes not to be dependent on surface it was abandoned.)
If to a solution of silver in a glass trough some grape-sugar be added, the
silver will be revived and spread itself uniformly on the surface of the glass,
as a bright mirror surface. If to a solution of silver we add carefully a few
drops of hyposulphite of soda-not sufficient to produce a precipitate-and
place this aside in the dark at perfect rest, after a period, a film of black
sulphide of silver will form upon the sides of the vessel in which it is
placed. Many other experiments might be mentioned in illustration, but
when the influence of electrical force comes under notice they will be
considered.
If a mass of clay is moistened with a weak solution of some metallic
salt, such as the sulphate of copper, and it be allowed to dry slowly, after
it has been kept for some time in a damp place, there will usually be found
some small threadlike veins or little nodules of copper in the form of
carbonate or oxide. These have been formed by a process of segregation.
CHAP. III.]
STRINGS OF TIN IN CLAY-SLATE.
347
In the Clay-Slate of St. Agnes-especially over the ground on which the
waste of Trevaunance and Polberro mines is heaped-we find examples
of nature working as we have illustrated in our small experiment. Sir
Henry de la Beche gives two examples of Slate containing strings of
oxide of tin.
The annexed woodcut (Fig. 51) is a sketch, on a reduced scale, of a speci-
men of slate containing strings of oxide of tin from St. Agnes, and illustrates
Fig. 51.
Fig. 52.
"complicated minor fractures subsequently filled with a metallic oxide."
These specimens may be collected in abundance in St. Agnes, and they
show an arrangement of parts which are improperly termed heaves, being
nothing but numerous small fragments of slates, the result of minor
fractures. Fig. 52 is another specimen, thought to be highly illustrative
of such heaves, but they really are only fractures produced by the expansive
force of crystallization.
The dissemination of tin extends over the whole of the promontory of
St. Agnes-on which several mines are situated—to such an extent, that it
has been said if an extensive battery of stamps were placed at Trevaunance
pier and the entire hill crushed into powder and "dressed"-as the phrase
is-the tin which would be obtained would pay for the machinery and the
labour bestowed upon it. There are many other places where the oxide of
tin is found as widely disseminated.
The Granite of Cligger-head, at Perranzabula, is traversed by thin veins
of quartz, and both the Granite and the veins contain tin ore. During the
summer months a solitary miner will be found breaking out masses of the
decomposed Granite and allowing them to roll down to the beach at
the base of the cliff. These masses are beaten, and broken, by the heavy
waves which roll in during the winter season. The lighter constituents of
the rock are washed away, but the fine grains of tin are, from their specific
gravity, deposited below the sand. At low tides, when the weather permits,
the miner is found gathering the oxide of tin, which has been separated
for him by the ocean waves since he broke them from the beetling cliff.
(c.) Lateral Infiltration.-It will be readily understood that a fissure
formed by any means in a Granite, or Slate, or Limestone rock, will form a
passage through which the water filtering from the surface will find a channel
for escape. During this process many of the salts held in solution will be
deposited upon the faces of the rock exposed in the fissure. Gustavus
Bischof* has accumulated information as to solvent powers of pure water,
* “Elements of Chemical and Physical Geology." By Gustav Bischof, Ph.D.
348
[BOOK II.
THE FORMATION OF DEPOSITS.
and of waters containing carbonic or other acids, but additional experiments
are required. Is it not probable that waters derived from rocks of various
descriptions may hold oxygen or ozone, or fluoric or silicic acids, and that
these aid in dissolving the metals and earths it may meet with, in its slow
infiltration through a great thickness of the rock?
(d.) Descending Waters.-These are only to be distinguished from the
waters of infiltration, as being poured into the fissured channel from the
surface of the Earth, accumulated by all those conditions which belong to
surface drainage. Such waters will carry with them the materials which are
found in running rivers and in springs.
(e.) Ascending Influences.-These will be waters varying in temperature,
according to the temperature of the depth from which they ascend, or
from the heat produced by the decomposition of pyritic ores in the strata
through which it has passed. Or it may be water vapour-steam—formed by
some igneous influence in operation at some considerable depth beneath the
Earth's surface. Water vapour at elevated temperatures may possibly
dissolve many substances not usually soluble in that fluid at a low tem-
perature. This, consequently, cooling in its passage through the fissured
rock, would part with some of the solid matter in solution, and deposit it
on the sides of the crack.
(f.) Sublimation.-Many of the constituents of our mineral lodes are sus-
ceptible of being vaporised under the influence of intense heat: all our
sulphides, arsenides, fluorides, and the like, might possibly have been formed
in this way.
(g.) Injection.-Supposes the matter of lodes to have been injected into
the rocks or fissures in a state of igneous fusion. The evidences of the con-
ditions e, f, g, are to be found between St. Just and St. Ives, where both
the Granite and the Slate are traversed by lodes, which may probably be
due to the influence of an elevated temperature.
The central region is productive of tinstone, and in the district of St. Just
and St. Austell the tin ore not only forms numerous thin veins, but is so
generally disseminated as to be regarded as an ingredient of the rock. At
Bejowans, in Sancreed, in the bed of a confluent which extends from Trego-
nebris to the coast at Lemorna-where the large Granite quarries are-we
have the following section:-
1. Granitic sand and gravel mixed with small angular and subangular masses of
Granite .
2. Peat, in which nuts and branches and roots of hazel (?) are imbedded here and
there
3. Granitic sand, gravel, and pebbles, interspersed with large boulders of Granite
4. The tin ground, being in a great measure wood tin of a divergingly fibrous
stratum, with which crystals of quartz are sometimes imbedded
•
6 to 12 ft.
2 to 8 ft.
•
6 inches.
2 to 9 ft.
Where the Granite bed (shelf) is soft, the tin ore is the most plentiful.
The rocks of the following districts have produced, and some of them are
still producing, tin ore; all of them presenting the appearance of having
been subjected to considerable heat.
Cold-harbour Moor, between Towednach Church and Amellibrea.
Tregilliow, on the confines of Ludgvan and St. Hilary: in the vale at
the end of Marazion Marsh, the tin is diffused through matrices natural to it
CHAP. III.
TIN VEINS AT BALLESWIDDEN.
349
in the metamorphic Slate veins. In Sancreed, the tin occurs in thick con-
cretions, capping crystals of quartz.* And in Sennen it is found diffused
extensively in rocks of admitted igneous origin.
At Tregadgwith, in St. Burian, similar conditions prevail.
At Porkellis Moor, in Wendron, at Carn-wartha, the disintegrated Granite
contains short veins of quartz and schorl, impregnated with tin ore. At
Mean-vroar, the veins discovered in the Granite shelf display the outcrops
of small strings which were worked to advantage. From Porkellis to Trenear
and thence to Helston tin ore is found, copiously disseminated in the rocks,
which have evidently, at one time, been plastic by heat.
In 1878, Captain T. P. Rowe and Dr. C. Le Neve Foster read before the
Royal Geological Society of Cornwall some observations on Balleswidden
mine. This is so important a record of a mine which was abandoned in
1873, and produced in the thirty-six years it was working more than 12,000
tons of black tin (oxide of tin), of a value of £694,094, that the following ex-
tracts are made from it, especially as exhibiting the phenomena of stanniferous
diffusion:
"THE AWBOYS LODE is situated in the southern part of the mine. The
bearing of this lode is about north 42° west (true) for more than a quarter of a
mile; on going northwards it turns 10° more to the west. The dip is south-
west, varying from 75° at the south-east part to 60° at the north-west extremity
of the workings (underlie, 18 inches to 3 feet in a fathom). The structure of
this lode deserves particular attention; the so-called lode consists of four or
five small parallel tin veins, bounded on each side by a hard rock, locally
known as hard-work, which merges into Granite. The total width of the lode
varied from 10 to 20 feet, and averaged about 12 feet. Each little vein or
leader, known at Balleswidden as a gry, was generally about a half-inch thick,
and rarely widened out to more than 4 inches. The gries rarely united with one
another along the dip or the strike, but often dwindled away to a mere string or
joint. The filling-up of these little veins consisted of coarsely crystallised
tinstone, with schorl, quartz, Gilbertite, and Kaolin (prian); a little wolfram,
fluor-spar, bismuthine, and native copper were also sometimes met with.
The little veins or gries were continually varying in productiveness; as a
rule only one of them was rich in any given section, and as soon as it began
to dwindle away one of the neighbouring ones began to improve. There
was always a sharp and well-defined wall between the gry and the adjoin-
ing hard-work; and this was of importance to the miner, as it enabled
him to separate the rich gry from the poorer rock adjoining it, and make a
little parcel of best work. The greater part of the tin was contained in the
gries.
"The hard-work on each side, from 2 to 6 inches wide, is a granular
mixture of quartz, schorl, and Gilbertite, with a little mica, fluor-spar, and
tinstone. The tinstone is almost always very finely disseminated through it.
Occasionally pseudomorphs of quartz and of Gilbertite, after orthoclase, were
observed in the hard-work, and coarsely crystallised tinstone has also been
found filling up cavities left by the removal of the same mineral. There was
never any wall or sharp plane of division between the hard-work and the
* "Manual of Mineralogy." Greg and Lettsom.
350
[BOOK II.
THE FORMATION OF DEPOSITS.
Granite. The portions of this rock lying between the bands of hard-work
were often soft and decomposed in the middle, forming what the Balleswidden
miners called gook. The Granite usually presented large and well-developed
crystals of orthoclase.
'Fig. 53 shows the general appearance of the lode. A B C D E are gries
+
A
X
XX
хах
bounded on each side by hard-work,
and G G G G, &c., are the intervening
bands of Granite, either decomposed
for their entire width or only in the
central part. G' is the Granite on the
sides of the lode.
"At the south-east part of the mine
the workings were shallow, and the
lode was productive in some places up
to the surface. The enclosing Granite
was soft; but when it became hard in
depth the lode fell off in productiveness.
Proceeding to the north-west the lode continued to be rich to a greater and
greater depth.
Fig. 53.
++
“PIE LODES.—The name pie was used at Balleswidden to denote a rock
composed mainly of quartz, Gilbertite, schorl, and Cassiterite, often slightly
cellular. There were two special pie lodes. One ran about east and west,
+++,
+++
Fig. 54.
х
and dipped north about 80°. It started off
from Awboys lode and crossed the south
lode. The other pie lode went off from the
south lode, with a bearing of about south
20º east, and was nearly vertical. A cross
section of one of these pie lodes would be
much as shown in Fig. 54, whilst Fig. 55
gives the horizontal section where nume-
rous joints are seen running into the pie. The stippled part in each of these
woodcuts shows the extent of the ground worked away for tin.
X
хх
Fig. 55.
"Both the pie lodes were offshoots, as it were,
of the main lodes; they usually gave out a good deal
ホ
​++
of water at their junction with the main lodes.
The productiveness of the pie lodes decreased if
schorl predominated over the Gilbertite. The usual
thickness of the pie lodes was about 3 feet, but they
increased to 6 feet occasionally, and then dwindled
away all round the productive part to a mere string.
"The pie lodes are probably altered Granite,
where, owing to some slightly different chemical
action, there has been a larger amount of Gilbertite
formed from the orthoclase.
"The tinstuff obtained from the mine, that
is to say the gries, together with the adjacent hard-work, produced about
60 lbs. of black tin to the ton of stuff, or rather more than 2 per
cent."
351
CHAP. III.]
A MASS OF STANNIFEROUS GRANITE.
Ding Dong mine, in Gulval, is entirely in Granite, an Elvan course
running through it. It has been worked for 150 fathoms from surface.
No lodes come to surface. The ore is all small. A lode 12 inches wide is
regarded as a wide one. Strings run irregularly through the Granite in all
directions. Sometimes a vertical lode is met with, but it lasts but a few
fathoms and usually entirely dies out. Some of the strings lead to a good
bunch of tin, but these bunches are not continuous, although they often
yield a considerable quantity of ore. By the side of the Elvan course in this
mine a small vein of tin was continuous, and rich.
The chief agent said,
The antiquity of Ding Dong is considerable.
Many people say she was worked hundreds of years afore Christ."
The mass of Stanniferous Granite, in which this very old mine existed,
lies partly in the parish of Madron, and partly in Gulval. The appearance
of the rock is peculiar-it is Granite, with green and pale brown felspar and
quartz and dark mica. The Granite is coarse-grained, porphyritic, and
frequently decomposing. The main lodes which traverse it are known as the
Bossilliack, which has a direction 30° south of west; Malkin, which has a
similar direction; the Bussa Trawn, with a direction 33° west of north; and
the Bucca Trawn, running north-west and south-east. The Bossilliack lode
is split into several branches, which are filled with quartz, schorl, and
felspar. The Malkin lode is exceedingly peculiar. It consists of quartz,
schorl, felspar, and oxide of tin. At the 57-fathom level the lode has a
northerly dip, generally varying from 77° to 84°. Three veins of disinte-
grated Granite traverse the lode. Two of them simply intersect, but the
third heaves the lode 4 fathoms; it bears north-west, and dips east 82°. The
lode varies in a peculiar manner-at 57 fathoms it consists of two veins of
quartz, felspar, and schorl, with oxide of tin; at 68 and 80 fathoms a
similar condition prevails; and immediately below 80 fathoms we find
earthy-brown iron ore, chloride, and oxide of tin. The Bussa Trawn lode
and the Bucca Trawn contain principally brown iron ore, with quartz and
schorl. Within this comparatively limited sett there are laid down on the
plans no less than twenty-two distinct lodes.* These lodes were constantly
throwing out branches, and disseminating strings to such an extent as to
appear to fill the Granite with mineralised veins. On the maps by the
Geological Survey Ding Dong mine is indicated by two lodes only, both
having a direction a little south of west; and these lodes are crossed by
three faults, having a direction nearly magnetic north, which are partly
mineralised. It is not easy to understand how this isolated portion of
Granite became so stanniferous, situated as it is in the middle of the great
Granite mass of West Cornwall, unless we refer to the action of heat main-
taining a prolonged plastic state after the consolidation of the surrounding
portion.
* The names given to these lodes were the following:
1. Coit lode.
2. Red lode.
3. Stand lode.
4. Stratons lode.
5. Bussa lode.
6. Bucca lode.
7. Wig lode.
8. Scorran lode (4 branches).
9, 10. Unnamed.
II. Trawn lode.
12. Slide lode.
13. North Standard lode.
14. Jacobine lode.
15. Ventenega lode.
16. Bossilliack lode.
17. Afters lode.
18. Black lode.
•
19. Bolitho's lode.
20. Ding Dong lode.
21. Wheal Boys lode.
22. Cluckey lode,
352
[BOOK II.
THE FORMATION OF DEPOSITS.
This condition of the Stanniferous Granite gave rise to the deposits of
detrital tin between Higher Carnon and Restronguet Creek. "At intervals
within my recollection," says Mr. Henwood, "these works have been carried
on by five several parties of speculators in succession. The first two as open
works (the last of which afforded a profit of about £50,000); but by the other
three in shafts sunk deeper than the bed of the inlet, and by drifts in which
the miners worked whilst laden ships sailed overhead." The first of the
mining works afforded a profit of about £28,000. The second eventuated in
a loss of about £16,000.*
Mr. R. Thomas † thus describes these works: "The open stream works
were found sufficiently profitable to induce the adventurers to extend their
operations down the navigation nearly a mile and a half. But latterly the
work has been carried on in another way. A shaft was sunk in the firm
rock on the shore, and a drift was extended from the bottom, by which
means the tin was obtained by removing only a small part of the mud which
covered it. . . . . These operations have been sufficiently successful to induce
the adventurers to extend their works half a mile further down: two shafts
having been recently sunk through the mud in the middle of the creek, and
secured by lining them with iron cylinders. The lower shaft is surrounded
by an artificial island formed of stones and rubbish on which is erected a
steam-engine."
About the middle of the navigable channel near Point, where the bed of
Restronguet Creek is some 12 feet below high water at spring-tides, a shaft
has been sunk by Messrs. John Taylor & Sons through the deposits named.
The following section was in one case measured by Taylor, in the other by
Whitley :-
Whitley, C. E.
I. Mud of river very soft
2. Mud and coarse sand
3. Mud hardened
4. Mud mixed with oyster-shells
5. Mud hardened
6. The tin ground (mean)
Taylor.
6 ft.
7 to 9 ft.,.
8 ft.
9 ft.
6 ft.
12 ft.
•
•
31 ft.
9 ft.
36 ft.
4 ft.
6 in. to 6 ft.
Gold has been found in the tin streams, and as usually derived from
igneous rocks, this fact is interesting.
“Some five-and-thirty years ago" (written in 1873), "whilst examining
a small parcel of stream tin from this district, I found amongst it a lump of
gold nearly if not quite as large as a pea” (Henwood).
A piece of gold, in a matrix of quartz from Carnon Vale, in the Royal
Institution of Cornwall, weighs 11 dwts. 6 grs. +
Gold was found in the bed of the brook, from Tarnon-dean upwards as
far as Trewedna water."§
Lower Creang-Masses of flint and crystals of gold occur at wide
intervals.
Trelog.-"The tin stream at Trelog was frequently mixed with grains of
*"On the Detrital Tin Ore of Cornwall." By William Jory Henwood.
4+++
<<
History of Falmouth." By R. Thomas, Surveyor.
"Manual of Mineralogy." By J. Mitchell.
Gwennap a Descriptive Poem." By W. Francis.
CHAP. III.]
VEINS OF SEGREGATION.
353
gold, mostly about the size of wheat, and sometimes as large as peas."-
Mr. F. Nicholls, proprietor, M.S.
Newquay.—The raised beach at Fistral, near Newquay, frequently afforded
granules of gold.
"Gold has been found mixed with stream tin ore in Kenwyn, Ladock,
Probus, Creed, Saint Ewe, Saint Mewan, Gorvas, St. Stephens, St. Austell,
Lanlivery, Lostwithiel, but the entire produce of the country can scarcely
have exceeded a few pounds" (Henwood).
Carclaze mine, near St. Austell, is another remarkable example of a
mass of decomposing Granite intersected by numberless veins and strings
of tin ore, in the neighbourhood of which the Granite also contains dissemi-
nated tin. Professor Sedgwick* says of this district: "In all the crystalline
Granitoid rocks of Cornwall there are also many masses and 'veins of segre-
gation.' Such are the masses and veins of schorl rock, and some of them
are metalliferous. The decomposing Granite of St. Austell Moor is tra-
versed, and sometimes entirely superseded, by innumerable veins of this
description."
Again the same geologist says, speaking of the open works at Bunney :
"Tin is also disseminated in regular crystals both in the Granite and schorl
rock, where we have no appearance of any regular vein distinguished from
the rest of the formation." Are these stanniferous rocks igneous ?
Mr. Henwood, speaking of the diffusion of metallic minerals through
the rocks, says: "Small crystalline granules of tin are dispersed through
and form an integral part of the Granite of Balleswidden,† Raggy-Rowal,
Wheal Vyvyan, Carclaze, Kit-Hill, &c., of some portions of the Elvan courses
at The Wherry, Parbola, Relistian, Wheal Vor, Unity Wood,‡ Polberro,
and of the Slate of Fat-work. But for the opportune occurrence of copious
streams at Carclase and Wheal Vyvyan, probably these mines would have
remained unwrought and their physical structure unknown."
The Granite mass extending from Penzance and St. Ives to the Land's
End is, with the exception of the district around St. Just, and a few
localities on the coast, but slightly metalliferous. At Balleswidden, and at
Ding Dong, we find exceptional conditions. It is necessary that attention
should be directed again to the course, or bed of rock, in Balleswidden,
called the lode. It bears about 30° north of west, and dips south 60°, 80°.
It is composed of ill-defined and confused mixed crystals of felspar, quartz,
a little white mica, and some schorl, among which considerable quantities
of oxide of tin are irregularly distributed. This is worked from 12 to 30
feet in width, and it is traversed by numberless small veins which have a
general coincidence with the mass, both in direction and dip. These are
frequently mere lines in the rock, and but few of them are more than 3 or
* Address to the Geological Society, February 18th, 1831. ("Philosophical Magazine and Annals,"
1831, ix. p. 2844.)
† "It is customary in almost every part of the county to cut up the sod as well as the heath growing
on the downs for the purpose of fuel. An examination of the turf taken up at Balleswidden has brought
to light the fact that it contains tin ore-a most striking proof of its universal diffusion through the coarse
soil as well as the rock of that neighbourhood."-Henwood, "On the Metalliferous Deposits of Cornwall.”
(Geological Society of Cornwall.)
At Wheal Unity Wood both the Elvan courses are so rich in tin ore that they are worked as, and
sometimes called, lodes.
A A
354
[BOOK II.
THE FORMATION OF DEPOSITS.
4 inches wide; they consist almost entirely of oxide of tin, quartz, and
schorl, and are generally very rich. They frequently divide, reunite, and
possess all the ordinary character of lodes, and the cavities with which they
abound are lined with minute but perfect crystals.
At Balnoon, in the Lelant district, the tin is found in masses unconnected
with any lode, and disseminated through a hard and very coarse Granite. A
few examples in other districts will prove instructive.
The Germans apply stockwerk (stock-work) to large masses of rock impreg-
nated with metallic ores.* Beyond those already named, we have some very
interesting examples of a similar kind near St. Austell.
Wheal Prosper and
Michell are open workings about half a mile west of Lanivet Church, between
Bodmin and St. Austell. These workings are upwards of 800 yards in
length, with a width of 30 yards, in the Clay-Slate. The rock is interpene-
trated by numerous little tin veins running east 7° north, true. These veins
are mere strings rarely more than 1 inch wide, and there are occasionally
caunter-lodes, which are likewise stanniferous.
Mulberry mine, about a mile and a quarter north-west of Wheal Prosper,
is a large open quarry about 300 yards long from north to south, and
30 yards wide at the bottom. At the north end the pit is about 120 feet
deep, and 80 feet at the southern end. The Killas (clay-slate) dips at an
angle of 45° degrees in a direction north 22° west, true, and it is traversed
by branches or veins running north 7° west, dipping from 80° to 90° west
and varying from mere joints to veins of 4 or 5 inches in width; and some-
times a floor or vein of tin follows the stratification.
Minear Downs, about 1 mile from St. Austell, is a large open working
about 200 yards long and 60 or 70 yards wide, having a depth of 120 feet.
The strings in this quarry are often mere cracks, being occasionally inch
wide.
Carrigan is 2 miles north-east of Roche Rock. The stratum here is greison,
which is merely altered Granite. This is worked open at Crogan Rock to a
length of 100 yards, a width of 50 yards, and a depth of 60 feet. The mass is
full of clay veins, or flucans, containing tin.
The tin ore obtained from the "Stream Works" near St. Austell has been
derived from the Granite and the Slate rocks which rise above the valleys
in which the detrital beds have been found. The examples which have
been given will sufficiently prove this; and we have seen that there exists a
large amount of evidence showing that considerable tracts of country have
been removed by denudation and produced those detrital deposits. We
have numerous examples of tin ore existing as one of the constituents of
rocks which exhibit very marked mineral characters.
Sir Henry de la Beche says: "Those who have studied the decomposed
Granite near St. Austell, traversed as it is by a multitude of branches and
strings of oxide of tin, would have little difficulty in perceiving that if a body
of water were made to rush over it, the decomposed Granite would be readily
removed, and that the broken-up strings and branches of tin ore would be
*See C. Le Neve Foster, "On some Tin Stockwork in Cornwall." ("Quarterly Journal of the
Geological Society," August, 1878.) J. H. Collins, "On the Hensbarrow Granite." ("Transactions of
the Royal Cornwall Geological Society.")
CHAP. III.]
TIN MINE IN RESTRONGUET CREEK.
355
rolled into pebbles and distributed just as the stream tin now occurs down
the valleys in the neighbourhood."
The evidences of the decomposition of the Granite and the formation of
Kaolin do not appear to be entirely satisfactory, but this is not the place
to examine a very intricate problem. Suffice it to say that probably the vast
masses of china-clay and china-stone which exist around St. Austell, and on
Dartmoor, may represent imperfectly formed rather than perfect Granite, which
has suffered decomposition either by the reaction of the atmosphere or of the
drainage waters from the peaty mosses which usually rest upon its surface.
The bed of the sea would be expected to yield large quantities of diluvial tin
ore, seeing that all the rivers from the Granite hills flow into it; but this is not
generally the case. A few instances may be named. In St. Just, on the beach
a little below Little Bounds mine, some men occasionally are repaid for the
labour they bestow. At Loo-pool Bar a little black tin has been found, and
in 1860 a tin-furnace was discovered buried in the sands. From Gunwallow,
Mr. John Jope Rogers, of Penrose-who was the owner of the dues there-
received money for small quantities of tin found in the hollows of the rock.
At Perranzabula, on the sands-especially around Perranporth-consider-
able quantities of black tin have been from time to time recovered. In nearly
all these cases this tin has been derived from the breaking up of the cliffs
around the coast. Those instances are given as showing how extensively tin
is distributed through rocks which are usually regarded as of igneous origin.
It may still be advantageous, as showing the enormous quantity of matter
which has been removed, to give a few additional examples of the peculiar
characteristics of the deposit of tin in the valleys of Cornwall.
We have already mentioned the stream works in Restronguet Creek.
Mr. C. H. Taylor, of Devoran, who had for some years the management of the
operations carried on in that estuary, gives the following description of them :
"The object of these works was to recover a valuable deposit of Stream
Tin which is found under the water in Restronguet Creek, and lies on the
rock beneath the mud and silt that form the bottom.
"The Carnon Valley, which has its outfall in the Restronguet Creek, was
in the last century the site of one of the most important stream works in
Cornwall; and the old streamers followed the tin bed some way down into
the creek, keeping out the tide by means of large embankments, of which a
great part still remain, and removing the whole of the overlying silt to get
at the tin. The tide having broken in over the embankment about the year
1800, the works were then abandoned; but about 1822 the working of the
tin bed was resumed by mining under the silt of the creek, and this was
successfully carried on for about five years. Some time later a lower part of
the creek was similarly worked, and operations were continued until 1843,
the remains of which are still to be seen in the old mine on the island in the
middle of the mouth of the creek.
"In 1871 the most recent operations were commenced for working the
portion of the tin bed known to remain unwrought between the two old
mines. Both of the old workings had been much troubled with water, the
levels not being always deep enough to drain the dips in the rock; it was
therefore decided in the new workings to drive a deep main level in the rock
A A 2
356
[BOOK II.
THE FORMATION OF DEPOSITS.
at 4 fathoms' depth below the tin bed, which should act as a drain, and also
serve as a tramway level for removing the stuff.
"It was found that the covering of mud and sand above the tin shelf was
about 60 feet in thickness; the bed of tin was from 1 to 4 feet thick, resting
immediately upon the rock. A shaft was sunk through the rock to a depth
of 18 fathoms on the beach below high-water mark, and a level driven out to
the middle of the creek 9 feet high and 5 feet wide. The tide was kept out
of the shaft by means of a wall, built up from the rock, of timbering and
puddle. An iron shaft was also sunk at the same time in the middle of the
creek for securing good ventilation of the workings. It was sunk in a bank
of soft mud covered 10 or 12 feet with water at high tide, a staging being
made by piles driven 12 feet into the mud, and supported from sinking by
cross timbers bolted to piles just below the surface of the mud. The shaft
was constructed of iron cylinders in lengths of 6 feet. The first cylinder was
made sharp at the bottom for entering the mud, and was sunk into the mud
by the weight of two other cylinders upon it. The core was then cleaned out
and further cylinders forced down by pressure from the chain of a crab-winch,
and afterwards by the weight of barges loaded with stone, and made fast at
high tide, so that the weight came on the cylinder as the tide fell. A total
weight of about 250 tons was required to sink the cylinder as it neared the
tin bed, which was about 3 feet thick at this part. About 78 feet of cylinder
were sunk to make this shaft; it is about 4 feet above the engine shaft, and
thus forms the upcast in the ventilation of the mine. The difference of 4 feet
in the height of the two shafts is found sufficient to maintain thorough
ventilation throughout the whole of the working by natural means alone,
without the need of resorting to artificial methods for the purpose. From
this shaft two levels were driven, east and west towards either shore of the
creek, and from these, two parallel levels were cut at right angles to the first,
which extended northwards for 90 fathoms. These served as the basis of the
workings, but soon other levels followed, all of which had to be secured with
timber as the mud quickly began to crush very heavily. In the two main
levels a frame, or 'set,' is fixed at every 2 feet; in the other levels the sets
are smaller and further apart. Much injury occurs at times to these sets
by the swelling down of the mud, but as this is gradual, and never sudden,
they can always be replaced or repaired. The workings in the tin bed are
quite dry, with the exception of the two main levels that are driven up the
creek, where there is a little water coming in from the rock in the bottom of
the levels. Not a drop of water finds its way through the mud, although at
high tide there is a depth of 12 or 14 feet of water over it. The tin bed
varies very much in thickness and in productiveness; in some places it is as
much as 7 feet thick, and in others only 3 inches, and the produce varies
from 15 per cent. to only 1-10th per cent. of black tin (oxide of tin). The
top of the bed is generally nearly level, so that as the surface of the rock
below rises or falls the gravel is thinner or thicker. The bottom of the bed
is generally much the richest in tin, but there is sometimes a second floor of
tin above richer than that below, and having a different quality of waste
associated with it, as if deposited at a different period. Some of the boulders
found in the bed weigh as much as 3 cwt. In the old workings, and also
CHAP. III.]
SECTION OF HAPPY UNION TIN MINE.
357
recently in the new, some fossil remains of stags' horns and bones, &c.,
have been met with; and in washing the tin several small particles of gold
have been found, some of nearly 4 grains weight. Much larger nuggets of
gold are stated to have been found in the old workings. The mud imme-
diately over the tin bed is often full of shells, some in good preservation;
and in driving one of the two main levels the trunk of an oak-tree was met
with, and had to be cut through; it was sound and tough, though soft, and ·
was quite black throughout."
The tin deposit of the Pentuan Valley has been already referred to. We
avail ourselves, however, of the following section of the "Happy Union
Tin Stream," which gives some very interesting and important facts bearing
on the sources from whence this immense mass of detrital matter has been
derived.
"(a.) Tin ground of unequal thickness, according to the inequalities of the surface of Grauwacke
beneath (3 to 10 feet). With it are rounded pieces of Granite and other rocks of the St. Austell hills, traversed
by the valley, as also fragments of Grauwacke and Greenstone, which having been transported a short distance
are more angular. Most of the tin occurs at the bottom of this bed, though it is sometimes found
in the higher parts. The tin is from the size of the finest sand to pebbles of 10 lbs. weight; and some
rocks, richly impregnated with tin, weighing 200 lbs. and upwards, have sometimes been found
there. The small tin, which is known by the name of grain-tin, is of the best quality; the larger
stones contain more waste, and sometimes also copper and mundic. Roots of trees are seen in
this ground, and on the top of it oyster-shells still remain fastened to some of the large stones and the
stumps of trees. The roots of the oak are in their natural position, and may be traced to their smallest
fibres, even so deep as two feet; from the manner in which they spread, there can be no doubt but that
the trees have grown and fallen on the spot where their roots are found.
66
'(b.) A stratum of dark silt, about 12 inches thick, apparently mixed with decomposed vegetable
matter, and on the top of this a layer of leaves of trees, hazel-nuts, sticks, and moss, from 6 to 12
inches more.
The moss appears in a perfect state, retaining almost its natural colour, and seems to have
grown where it is now found. This layer of vegetable matter is about 30 feet below the level of the
sea at low water, and about 48 feet at high-water spring tides. It is not found in particular spots only,
but extends, with some interruptions, across the valley.
"(c.) A bed of sludge or silt, 10 feet thick, changing from a brownish to lead colour in particular
places. The whole is sprinkled with recent shells, together with wood, hazel-nuts, and sometimes the
bones and horns of deer, oxen, &c. The shells, particularly the flat ones, are frequently found in rows or
layers; they are often double and closed, with their opening part upwards, so as to render it likely that
the animals lived and died where their remains are now found.*
"(d.) A bed of sand, about 4 inches thick, contains (marine) shells, and the water which drains
from it is nearly as salt as the sea, whilst all the water above and below it is fresh.
"(e.) Silt or clay, 2 feet thick.
""
(f.) Sand, 20 feet thick. In all parts of this sand there are timber trees, chiefly oaks, lying
in all directions, and also the remains of animals, such as parts of red deer, &c.+ Bones of whales are
found in it; the bones of a large one were discovered in the upper part of this bed, as well as those
of others in the lower portions of it.
"(g.) A bed of rough river sand and gravel, here and there mixed with sea sand and silt, about
20 feet thick and extending to the surface. Mr. Colenso states that a short time before he described
this section (1829) the remains of a row of wooden piles had been found in this sand, sharpened for the
purpose of driving, and that they appeared to have been used in the construction of a wooden bridge for
foot passengers; they crossed the valley, and were about 6 feet long, their tops being about 24 feet
from the present surface, just on a level with the present low water at spring-tides. He remarks that
* These shells are of the same species as those which now exist in the neighbouring sea; their
appearance in the lead-coloured silty clay strongly reminds the geologist of that of the shells in the
sub-Apennine lead-coloured clays, such as those of Nice and other places.
It
Mr. Colenso states that, at about the time he wrote (1829), a piece of oak had been found in this
silt, about 2 feet from the top, which appeared to have been brought into form by the hand of man.
was about 6 feet long, 1 inch broad, and less than half an inch thick. It appeared to have floated in the
sea, as at one end, which was much decayed, a small barnacle had fixed itself.
† Mr. Colenso notices human skulls as having been found in this sand.
358
[BOOK II.
THE FORMATION OF DEPOSITS.
if the sea-level had been then as now such a bridge would have been useless. These works are
now abandoned; but in 1837 others were carried on higher up the valley on the south of the London
Apprentice inn; from which it would appear that from the general rise of its bottom the sea had not
entered this valley sufficiently high to permit marine deposits to be there accumulated. The tin ground
was covered by gravels, sand, and silt, among which trees, chiefly oak, were irregularly distributed, the
whole probably being the accumulation of river-drift during a long period of time."-Contributed, in
1829, to De la Beche's "Geological Report of Cornwall and Devon," pages 401, 402, by Mr. Colenso.
From the sources described black tin has been obtained from the earliest
recorded time. As we have already shown, ancient tin smelting works
have been found in all parts of Cornwall. Mr. Henwood has named five spots
only, on which these curious remains of old British or Jewish metallurgy
exist. The St. Austell moors alone would give a larger number, and the
parishes of Sancreed, St. Just, Morva, and Zennor, to the west and north of
Penzance, would produce several. The number of old slabs called "Jews'-
house Tin," which have been recovered, are said by the same authority to be
eighteen only. A far larger number of these metallic masses have been found.
On the statement of "two eminent tin smelters," Mr. Henwood says, "The
entire county now yields only about 50 tons of stream tin in a year." This
may be perfectly correct so far as the natural deposits of the valleys are
concerned, but the following quantities of black tin were obtained in 1881
from rivers and beaches,-the deposits being derived to a great extent from
the neighbouring mines,-the 909 tons given, being principally gathered
from the loss suffered in the process of "dressing" the 11,944 tons of black
tin obtained from the neighbourhood of Camborne and Redruth. When the
preparation of tin ores for the smelter becomes the subject of comment,
this loss, equal in money value to £36,169, will be again referred to.
BLACK TIN OBTAINED FROM STREAMS, RIVERS, AND FORESHORES,
1881.
Names of Streams.
Quantities.
Values.
Tons. cwts. qrs.
Red River, Dressed Ore, Tin Roughs, &c.,
from Carn-Brea District
909
I I
£
s. d.
35,283 o o
•
Lelant Stream
6 19
1
Clegger Porth
O
7
O
Goonlaze and Ty Tyas.
O
•
5
O
Helston Stream
Letcha Foreshore
Spit Beach *
I 16
•
O 13
20
Short Horn Beach
Crinnis Beach
3
Trevaunance Beach
Trevellas Beach
Tregonetha Common
OMNO
6
I
15
2 5 3
33ON33
267 19 8
15 2
12 15 8
88 Ο ΙΟ
38 4
38
O
2
O II I
8 O O
167 13 11
70 4
114 4 4
24 6
9
O
•
Treworlis (Halvans)
Carbis Beach
Total.
•
4
I
201
3
6 16 6
I
О
O
63 14
O
9 13 9
957
I O
36,169 15 8
The examples which have been given will sufficiently serve to prove that
the black tin found in the lodes or veins may have been derived from the
* Sand containing but little black tin.
CHAP. III.]
BULLEN GARDEN COPPER MINE.
359
rocks in which it has been shown that tin exists as a constituent element.
Water containing mineral, or organic acids, may have acted as the solvent
and agent, and then have parted with the mineral salts in solution in passing
through the fissures of the rocks, or in filtration, through rocks which are
more or less porous.
When we examine the evidences of vast mutations, which are the result
of slow processes, continually in action through long periods of time, we can
but arrive at the conclusion that not only the detrital tin, but much of that
which is found in lodes, has been derived from this gradual disintegration
of the older rocks. The conditions prevailing in the districts of St. Agnes,-
in the Granite region which is represented by the Ding Dong mine,-in
the china-clay districts of Carclaze, and indeed of the neighbourhood of
St. Austell generally,-clearly point to the superficial sources from which
the vast quantities of detrital tin ore may have been derived.
The reverse of this picture must not, however, be neglected in the con-
sideration of this subject. Dolcoath mine, near Camborne, has been worked
for a very considerable time. In 1778 Pryce speaks of it as a mine which
had been for a long period in active operation. He gives an engraving of
Bullen Garden mine, worked, at that time, to a depth of about 110 fathoms,
and says:
"At a depth of from 50 to 60 fathoms is an aqueduct or level from
Dolcoath mine, and there is a deeper level driving to the same mine at a
greater depth." Therefore Dolcoath at that time must have been explored
to a considerable depth. The only existing evidence which we possess is that
given by Pryce, who shows two engine-houses, and these are supposed by
the present thoughtful manager of Dolcoath mine to correspond with "what
we now call Old Sump shaft, which is about 28 fathoms west of our present
engine-shaft."
The Bullen Garden is called by Pryce a copper mine, and it was not,
evidently, according to his description, identical with the present Dolcoath.
He speaks of their drawing the water from the Dolcoath mine, and of their
using a level to facilitate the drawing of mineral matter. Be this as it may,
Dolcoath clearly commenced as a copper mine. "There was no doubt,'
says Captain Josiah Thomas, "a little tin in the 'gossan' on the back of
the lode, but I do not think Dolcoath was worked as a tin mine in Pryce's
time. We have raised some hundreds of tons of gossan in the last few years
which produced about 20 lbs. of black tin per ton of stuff."
Certain it is, that subsequently Dolcoath was worked as a tin mine, when
after many years copper reappeared in the same lode. Then, at a great
depth, another change took place, and the mine is now worked as a tin
mine. By what theory are these remarkable changes to be accounted
for?
The following examples of the existence of copper ore as a constituent of
the rocks are instructive, as proving the diffusion of cupreous minerals :-
Yellow copper ore is an ingredient in the Granite at Wheal Vyvyan mine,
and in the Slate at Wheal Music. The ore is generally disseminated
through the rock in a sort of random sprinkling. These segregations of
copper ore are not formed on lines of regular bearing, but as nodules and
irregular and unconnected masses dispersed through the rock. Mr. Henwood
360
[BOOK II.
THE FORMATION OF DEPOSITS.
informs us that "numerous examples of copper pyrites and vitreous copper
ore dispersed in irregular and unconnected masses, and in minute veins
through the Slate, occur at Taren Belwyd and Cae Mawr, near Dolgelly,
in North Wales, and I have observed instances of both kinds at the Parys
mountain, in Anglesea.”*
The same conditions have been observed by the author in the neighbour-
hood of the Drws-y-Coed and Symdde Dylluan copper mines in Nantlle Vale,
near Carnarvon, and he has been informed that similar deposits are to
be seen in the vicinity of Cwmdyll, or the Great Snowdon Mountain copper
mine, and at the Turf copper mine, near Dol-y-frwynog.
The conditions of copper ore and lead ore in the Sandstones of Cheshire,
at Alderley Edge, and at other places already named, need only be referred
to here as remarkable examples of the diffusion of metallic matter.
A similar deposit was worked at Eardiston, near West Felton, Salop,
about twenty years since, and a section of the Limestone stratum and
cupreous shale bed at Pant, near Oswestry, is noticed by Mr. D. C.
Davies.t
In the Greenstones throughout Cornwall thin leaves of native copper are
found in the small joints or cracks which occur in this rock.
LEAD, in the form of sulphide (galena), is very often found distributed
in a crystalline form in the Slate and Limestone rocks. In Cornwall these
isolated crystals are to be found in the Chiverton district, and curiously
dispersed through the spathose iron lode, in the Duchy and Peru mine, in
Perranzabula. The same kind of segregation is to be found in the lead
districts of Liskeard and Menheniot, and also of Devonshire.
Williams remarks: "Lead, copper, and other ores are found in the compo-
sition of the solid body of the rocks in many places. I saw a stupendous
rock, at a place called Cwm-ystwith, in Cardiganshire, Wales, where so much
lead ore was found blended in the rocks as to be worth working and sepa-
rating from the rock. The rocks at Cwm-ystwith are of great height, and I
saw the miners there suspended in ropes blasting down the rocks with gun-
powder, and a number of busy hands breaking and knocking the compound
ore small, in order to get it separated by washing and dressing." The
same miner also writes: "One of the most remarkable rocks containing
metallic ore in the composition of the stone is the breccia, or pudding-stone,
at Gourock, near Greenock, in Scotland." “Both lead and copper are often
found in Limestone quarries in several counties, and I have seen good lead
and copper in Limestone in several parts of Scotland." He then enumerates
the copper ore found at Currie, in the Lothians; at Kissern, in the High-
lands of Ross-shire; and the brecciated rock at Lossiemouth, in Moray Frith.
It is curious, after this satisfactory statement of observations carefully made,
to find this author writing such a passage as the following: "I cannot help
being persuaded that perfect metallic ores being found in the body and
composition of regular Limestone and other solid rocks is not only an argu-
* "On the Metalliferous Deposits of Cornwall and Devon," p. 236.
↑ "Metalliferous Minerals and Mining," p. 136. By D. C. Davies.
Williams, "The Natural History of the Mineral Kingdom," vol. i. p. 357. 1789.
CHAP. III.] THE DISSEMINATION OF METALLIC ORES.
361
ment but a clear decisive proof that the materials which formed the several
ores and their intermixed and concomitant spars were poured into the
veins and taken up in the composition of the strata when they were first
formed."
A sufficient number of examples have been given to show that the ores
of tin, copper, and lead are to be discovered in several varieties of rock, distri-
buted in such a manner as to be fairly regarded as one of the constituents of
the rock itself. These might be largely increased if it was thought necessary
to do so. The dissemination of iron and manganese is so extensive that it is
difficult to find a rock without the oxides of one or other of those metals.
There appears indeed every reason for believing that if chemical investiga-
tions were carried on upon larger masses than those usually found in the
laboratory, and with those refinements of research—with the aid of the spec-
troscope, which must be regarded as the triumph of modern chemistry—the
presence of most of the minerals which are found accumulated in lodes would be
detected. At present, however, we are only in a position to prove that Granite
and Slate, with a few truly igneous rocks, contain tin and copper, lead and
iron, in their composition, and that Limestone, and some of the Sandstone
formations also, give evidence of the infiltration of lead and silver, cobalt and
iron and manganese. But our knowledge, imperfect as it is, gives a shade
of probable truth to the hypothesis, which accounts for the filling of fissures
-the formation of lodes-by supposing that water penetrating the rocks
dissolves infinitely small quantities of the metallic salts, and that these, by
physical and chemical actions, become deposited as metallic ore in the fissures
which have been previously formed to receive them.
The dissemination of metals, through certain rocks, is a subject upon
which much has been said, but really very little done. Silver, lead, copper,
and arsenic have been detected, either in sea water, or in the crusts
formed inside the boilers of ocean steamers. In the deposits formed on the
beds of the brine-pits of the salt works on the borders of the Mediterranean
-which are black and slimy-copper has been constantly detected, as well
as silver. Malaguti and Durocher have been very industrious observers
of these facts.*
M. Boussingault, in vol. xlviii. “Annales de Chimie et de Physique,"
Third Series, October, 1856, has a paper on the same subject.
In a memoir contributed to the Academy of Sciences by Malaguti,
Durocher, and Sarzeaud,† it was shown that silver is very generally spread
through all minerals, and the great diffusion of this metal led them to make
further researches as to its presence in sea water. This fact they clearly
established; and, further, they consider that the metals lead, iron, zinc,
and copper are held in solution in sea water as well. They have limited
their researches, however, to silver, lead, and copper, for zinc was not
found in such sensible quantities, and the presence of iron has been long
established.
* See “Observations relative à la présence de l'argent dans l'eau de la mer." Par MM. Malaguti
et Durocher. ("Comptes-rendu," quarante-neuvième, 1859, p. 536.)
† MM. Malaguti, Durocher, et Sarzeaud, "Recherches sur la présence du plomb, du cuivre, et de
l'argent dans l'eau de la mer, et sur l'existence du dernier métal dans les plantes et les êtres organisés.”
("Annales de Chimie et de Physique," 3e Série, tome xxviii.)
362
[BOOK II.
THE FORMATION OF DEPOSITS.
If silver is found in salt water it must also be present in sea salt. The
first experiments were, therefore, made on that substance, and silver was
extracted, both by the wet method by means of sulphuretted hydrogen, and
by the dry method by melting marine salt with pure litharge and pine-
soot. Many experiments were well and carefully carried out, and it was
proved that from even 100 grammes of rough marine salt, mixed with
25 of pure litharge and I of pine-soot, a very small button of silver
might be obtained. Although these experiments proved the presence of
silver in the salt of commerce, its existence in sea water might be produced
by accidental causes; so, to avoid all doubt, these chemists directed their
next researches on sea water carefully collected.
Ι
Many complicated experiments were made with undoubted success, and
the presence of silver-pure and simple-in sea water was incontestably
established, by the most simple method of precipitation by sulphuretted
hydrogen.
The next experiments were on the seaweeds. It is well known how
easily these plants assimilate iodine and other matters, and therefore it
appeared probable that they would absorb silver. Large quantities of
fucii of many kinds were dried and reduced to ashes, and silver was found
in nearly all of them. If the presence of silver is admitted in salt water and
in marine salt, it is clear that it must occur in many chemical products.
Artificial carbonate of soda is found to contain more silver than sea salt.
This is easily conceived when one thinks of the sulphuric acid and other
matters that are used in its fabrication, this acid being itself argentiferous,
as is also the nitric acid of commerce.
Experiments were next carried out on vegetables, and the blood of
animals, with equal success, silver in small quantity being found diffused
through each.
Rock-salt and coal were examined, and traces of silver were found in
both, though the authors consider the presence of silver in coal as not yet
sufficiently proved.
Having by a course of most carefully prepared and elaborate experi-
ments established the fact of the presence of silver in vegetable and animal
organisms, as well as in minerals, the authors of these researches next
turned their attention to the discovery of lead and copper in the same sub-
stances. Many successful experiments were made on several kinds of fucus
-lead and copper being constantly found. The authors remark: "The
presence of copper in organic nature being a fact now generally admitted,
one may conclude that if land plants draw this metal from the soil, the fucus
also must draw it from the waters of the sea, that is to say, the element in
which it lives." And they may justly conclude that if lead and copper
accompany silver in sea water, the same thing probably occurs in all the
economy of nature.
Although at first the presence of silver, copper, and lead in sea water seems
singular, yet, say our authors, it is easy to comprehend when we remember
how the sulphides of these metals are diffused through nature. The salt
water attacks these sulphides and transforms them into chlorides, which are
soon dissolved in the waters which circulate in the upper part of the Earth's
CHAP. III.]
DIFFUSION OF ZINC ORES.
363
crust, and which nearly always contains chlorides and other alkaline salts.
These act on the natural sulphides; they carry away from them small
quantities of the metals which they hold in solution, and by that means
they penetrate the tissues of plants, and also pass with food into animal
nature.
Several German chemists have examined this subject and obtained
similar results. We now know for certain that silver, lead, copper, and
iron are widely disseminated. From these researches we can readily under-
stand that from the vast reservoir of the ocean the metallic ore found in the
rocks may have been derived. Zinc is mentioned as being found in quantities
so small as to render its presence a little doubtful. The diffusion, how-
ever, of this mineral as sulphide, and carbonate of zinc, is proved by its
existence in considerable quantities in the shallow deposits of the iron.
ores of Northamptonshire.
In 1880 a memoir appeared in the "Annales de Chimie et de Physique"
showing that zinc existed, in a state of complete diffusion and in
sensible quantity, in the primitive formations, and also in the sedimentary
soils derived directly from them. M. Dieulafait* says there is no question
that has been more disputed than the origin and the mode of formation of
Dolomite. He does not now occupy himself with that question, but he
brings forward a conclusion at which he has arrived after careful experi-
ments. It is as follows: "The presence of bituminous matter in some Dolo-
mites is an established fact; but beyond this, the Dolomitic rocks constantly
contain ammonia in proportions which have sometimes exceeded 1 gramme per
cubic decimetre; that is to say, more than 1 kilogramme per cubic metre of
rock."
This appears to be a reason for supposing that the Dolomites are
not only sedimentary rocks in the ordinary sense of the word—that is to say,
rocks of which all the elements are contemporaneous-but that they are
produced in waters rich in organic matter. In a previous memoir it was
shown that the concentration of zinc was effected even under our eyes in
estuaries of a modern period. Following up these conclusions, and assisted
by several well-known facts, such as the near kindred which exists between
magnesium and zinc, the great analogy of their chemical combinations, and
the isomorphism of their salts, it seemed probable to the author that zinc
must exist in Dolomite deposits in sensible quantities. He made this
the subject of his researches, and studied carefully in the four great Dolomite
regions of France and Switzerland. He experimented on many samples
from these places, and in all these he discovered zinc.
Without occupying ourselves with the origin of Dolomite, but taking
only the chemical fact of the diffusion of zinc in the rocks, we arrive at one
important result relative to the origin of minerals of zinc as they exist at
present. It is this: minerals of zinc, particularly carbonate of zinc, are
always in direct relation with the Dolomitic rocks. "It is on these slopes
on the Mendip Hills, composed of magnesian conglomerate and of Limestone
of the same nature, that the calamine mines are situated” (Dufresnoy).
* "Existence of Zinc in a State of Complete Diffusion in Dolomitic Soil." By M. Dieulafait.
("Comptes-rendu.")
364
[BOOK II.
THE FORMATION OF DEPOSITS.
In Belgium, at the Vieille-Montagne, "calamine fills a depression in the
Dolomite." In Silesia the bed of calamine, considered all together, makes
a vast irregular mass; it is found in contact with the muschelkalk, some-
times covered by the Dolomite and sometimes in the Dolomite, branching
in all directions. In the south of Europe the zinc mines of Sicily are
as often in Magnesian Limestone as M. Lamarmora reports them to be in
Silurian.
From these and many other examples it becomes apparent that minerals
of zinc are contemporaneous with the Dolomitic Limestone in which they are
enclosed; on the other hand, if the Dolomites of the Silurian system
(Sicily), of the carboniferous soil (Belgium), of the muschelkalk (Silesia),
and of other still more recent formations, in spite of their prodigious differ-
ence of age, enclose minerals of zinc of the same chemical composition and
the same in all other details, it evidently shows that the same exceptional
circumstances are active at very different epochs, to reproduce the same
deposits.*
Mr. Frederick Field, on the 11th December, 1856, read a paper before
the Royal Society "On the Existence of Silver in Sea Water." †
After referring to the researches of Malaguti and others, he states that a
large vessel was hauled down in the Bay of Herradura, near Coquimbo, for
the purpose of being repaired, when the captain furnished Mr. Field with a
few ounces of the yellow metal from the bottom of the vessel. This brass
sheathing had been exposed to the waters of the Pacific for more than seven
years. The metal was found to be very brittle, and could be broken by the
fingers with ease. Five thousand grains were dissolved in pure nitric acid
and the solution diluted, a few drops of hydrochloric acid were added, and
the precipitate allowed to subside for three days. A large quantity of white
insoluble matter had collected at the bottom of the beaker and separated by
filtration. This was fused with 100 grains of pure litharge and other suit-
able salt, the ashes of the filter being added. The resulting button of lead
was subsequently cupelled, and yielded 2.01 grains of silver, or 1 lb. 1 oz.
2 dwts. 15 grs. troy per ton.
The captain of the Nina, a brig trading in the Pacific, gave Mr. Field
a piece of Muntz's yellow metal from his cabin, from the same lot with which
the brig was sheathed, but which had never been in contact with salt water,
and also a portion from the hull of the ship after it had been at sea for nearly
three years. The examination was made as before, the results being very
striking :-
1700 grs. from cabin gave 051 grs.
1700 grs. from hull ,, *400",
That which had been exposed
silver as the original sample.
(
Ozs. dwts. grs.
O 19
=
003 per cent.
*023
= 0
""
=
14 per ton.
""
7 13 I
to the sea having nearly eight times as much
Several other results are given showing that
* M. Chevreul refers to Proust, who, in a letter from Madrid, 4th April, 1787, published in the
Journal de Physique" a paper "On the Action of Sea Water upon Silver." Another note, published
in 1799, shows that mercury is found in sea water. See also "Annales des Mines," 4° Série, t. xvii. p. 94.
"Note sur un composé naturel d'oxyde de zinc, d'oxide d'ammonium et d'eau." ("Compte-rendu," 1866,
lxii. p. 413.)
+
Transactions of the Royal Society." ("Chemical Gazette," 1857, vol. xv. p. 93.)
CHAP. III.]
DISSEMINATION OF METALLIC ORES.
365
copper immersed in sea water acquires silver considerably beyond that which
it originally possessed.
Manganese is very generally diffused. Dieulafait finds the oxide in
considerable quantities in the Dolomitic rocks.*
M. Boussingault ("Annales de Chimie" for November, 1882) publishes a
paper "Sur l'Apparition des Manganèses a la surface des Roches," in which
he shows that carbonic acid extracts the manganese from all sources and
then deposits it on the rocks.
To recapitulate. It has been shown that tin has been found to be diffused
through the rocks of the peculiar character which belong to Cornwall and
Devon. Copper has even a more general diffusion over rocks dissimilar in
character. In addition to the facts already given, it may here be stated that
lead and copper (as at Alderley Edge) were found infiltrated amongst the
Bunter conglomerate, through which the sinkings at Fair Oaks Colliery in
Cannock Chase were made. At Fair Oaks the lead ore was within 29 feet of
the surface; at Shore Hill the copper ore occurred about the middle of the
100-feet section. Lead has been found in the oceanic waters, and in the
deposits in the boilers of steam-engines; silver has been found under several
circumstances; zinc has been discovered in rocks of very dissimilar geological
ages and in sea water; while arsenic and antimony have been detected by
M. Daubrée in combustible minerals in various rocks and in sea water. Gold
has not been named. There are no authorities of sufficient reliability who
can be given as discoverers of this precious metal in the state of extreme
diffusion. It is known to exist in connection with tin. It is also found to be
in certain copper ores-those of Fowey Consols may be especially named.
In the pyrites of Wicklow and other places, in some lead ores, and wherever
quartz lodes abound, gold is generally stated to be present.
M. A. Daubrée,† in a memoir presented to the Academy of Sciences of
Paris, has shown that a great number of little crystalline grains of a metallic
grey colour, which he has observed in the Coal-measure Limestone of Villé
(Bas-Rhin) are arsenical iron. He finds also in the coal, especially the
two principal varieties, the same mineral in the proportion of 0·169 gr. and
0'415 gr. per kilogramme (about 24 lbs. avoirdupois). Daubrée also traces.
arsenic in the coal of Saarbruck, in the lignites of Bouxwiller and of
Lobsam (Bas-Rhin). Traces of copper were also discovered. He finds
a proportion of arsenic in certain sedimentary beds, which derive their chief
materials from eruptive rocks on the one hand, and the waters of the ocean on
the other. In operating upon 100 grammes of the basalt of Kaiserstuhl he
has recognised, he informs us, in this rock, in unmistakable quantities, both
arsenic and antimony. Daubrée examined sea water and the deposits formed
in boilers, and in both these minerals were detected. Arsenic, he remarks,
* "Le manganese dans les terrains dolomitiques. Origine de l'acide azotique qui existe souvent
dans les bioxydes de manganese actuel." (Note de M. Dieulafait, présenté par M. Berthelot, Académie
des Sciences, Séance, Jan. 8th, 1883, "Compte-rendu," tome xcvi. p. 125.)—"De manganese dans les
eaux des mers actuelles et dans certains de leurs dépôts; conséquence relative à la craie blanche de la
périod sécondaire." (Note de M. Dieulafait, présenté par M. Berthelot.) He finds, "Des eaux de la mer
des Indes, de la mer Rouge, de la partie orientale de la Méditerranée, qui m'ont été rapportée par M. le
Mécanicien, m'ont donné exactement les mêmes résultats."
+ "Recherches sur la présence de l'arsenic et de l'antimoine dans les combustible minéraux, dans
diverses roches et dans l'eau de la mer." ("Comptes-rendu Hebdomadaires des Séances de l'Académie
des Sciences," tome xxxii. p. 287.)
366
[BOOK II.
THE FORMATION OF DEPOSITS..
is widely spread, not only in mineral veins but also in various rocks, where
it is habitually accompanied by phosphorus, as was first shown by Professor
Walchner. He then deals with the presence of phosphorus in the three
kingdoms of nature. Sulphur, especially in the state of sulphate, is univer-
sally distributed.
Professor F. Sandberger* has arrived at the conclusion that the contents of
lodes are in the main derived from minerals existing in the enclosing rocks.
Veins of heavy spar may have received the barytes from felspars containing
that earth, and so on. He attempts to prove the existence of valuable metals
in silicates. Olivine always contains nickel and cobalt; and olivine from
Nauroth, near Wiesbaden, contains 0.307 per cent. of oxide of nickel and
0006 per cent. of oxide of cobalt. In the palæopicrite or olivine rock of
Dittenburg, there is from 0.162 to 0.666 per cent. of oxide of nickel, which is
further accompanied by copper, cobalt, and bismuth. In many varieties of
hornblende Professor Sandberger has frequently found copper and cobalt.
The same metals are often present in augite, and specimens of that mineral
in diabase from Andreasberg afforded, in addition, lead, nickel, antimony,
and arsenic. Mica obtained from graneiss and gnite has yielded most of the
ordinary metals.
Professor Sandberger endeavours to show that the olivines, hornblendes,
augites, and black micas of crystalline rocks of all periods contain heavy
and noble metals. He points attention to the fact that lithia micas are
probably the original source of tin which is found in the lodes, and he
considers stannic acid may probably replace silica, as is already known to
be the case with titanic acid.
We have, therefore, a considerable amount of evidence which proves that
metalliferous minerals are extensively diffused over the surface of the Earth,
and that they are to be detected in the waters which are constantly beating
upon and wearing down the land. May we not, therefore, venture to suppose
that the metallic ores found in the fissures of rocks are derived in a great
measure from that reservoir of water which has existed since the Earth "was
without form and void, and darkness was upon the face of the deep?" The
geological evidence collected by reading the "sermons in stones" proves that
districts now high above the present sea-level were at one time far beneath
the waters. The sea must through all time, as it does at the present hour,
have been filtering through the rocks over which it flowed.
The soluble contents of mine water are deserving of especial attention.
Mr. J. A. Phillips has made most careful examinations of some of the
waters infiltrated into the deep Cornish mines. Wheal Seton copper mine
is situated about one mile north-east of the town of Camborne, in Cornwall,
and is distant from the sea a little more than three miles. The workings of
this mine are entirely in "Killas," or Clay-Slate, and the saline waters issue
at the rate of fifty gallons per minute, at a temperature of 92° F. This has
*The following papers by Prof. F. Sandberger have been published: "Zur Theorie der Bildung
der Erzgänge" [Theory of the Formation of Lodes] ("Berg- und Hütten.-Zeitung," 1877, XXXV.
pp. 377, 389); "Ueber das Vorkommen des Zinnes in Silicaten" [On the Occurrence of Tin in Sili-
cates] (Berg- und Hütten.-Zeitung," 1878, xxxvii. p. 202); "Ueber die Bildung von Erzgängen
mittelst Auslaugung der Nebengesteine" [On the Formation of Lodes by Solution from the Country Rocks]
("Berg- und Hütten.-Zeitung," 1880, xxxix. pp. 329, 337, 390, 402); "Untersuchungen über Erzgänge"
[Researches on Mineral Lodes]. Wiesbaden: 1882.
CHAP. III.]
ANALYSIS OF MINE WATER.
367
intersected a fault, or cross-course, which can be traced in a northerly direc-
tion to the sea, the source beyond doubt from which this hot spring has been
MINERAL WATER FROM WHEAL SETON.
Solid matter 14.3658 grammes per litre, or 1005.61 grains per gallon. Sp. gr. I.0123.
ANALYTICAL RESULTS.
Grains per Gallon.
I.
II.
Carbonic acid
5.56
5.50
Sulphuric acid
1.25
I'24
Silica
1.89
1.96
Chlorine
642.10
641.63
Bromine
trace
trace
Alumina
24.19
Ferric oxide.
Manganese
•22
trace
Copper
minute trace
24.221
•23
trace
minute trace
Lime
Magnesia
243.56
5:05
244'74
Alkaline chlorides
454:44
Potassium
Casium
Sodium
Lithium
Ammonia
Nitric acid
5.82
trace
160.84
5.63
trace
4'97
452.38
160.19
5.56
trace
5.84
trace
""
derived. The working on the lode a b, Fig. 56, has been driven on to its point
of intersection b, with the cross-course ƒ, and is believed to have been thrown
in a southerly direction from 6 to c. A dyke of
porphyry, G H, 40 feet in width, courses parallel
with the lode at a distance of a few fathoms to
the north. The direction of the dip is indicated
by an arrow. The water which issues from the
point w was collected and brought to the sur-
face in carefully cleaned stone-ware jars.
Mr. J. A. Phillips has also given analyses of
the Elvan, Granite, and Clay-Slate rocks, but
these do not appear to have much relation to
the water. It is important, however, to give
the conclusion to which this excellent observer
has arrived :-
G
a.
f
Fig. 56.
II
น
“Source whence the Mineral Waters of Wheal
Seton are probably derived.-Before attempting to account for the presence
of the mineral constituents found in these waters, it will be necessary to
consider the bearing and importance of the following facts:—
"(a.) The average elevation of the surface of the mine is about 300 feet
above the sea; and the 160-fathom level, being 960 feet below the adit or
drainage-tunnel and 1,080 feet from the surface, is consequently much
beneath low-water mark.
"(b.) The cross course, shown in the Geological Map, may, as has been
already stated, be traced for a distance of three miles to the coast, and
368
[BOOK II.
THE FORMATION OF DEPOSITS.
apparently forms the channel through which the saline waters effect an
entrance into the workings.
"(c.) The water contains a very large proportion of chloride of sodium.
"(d.) Similar springs of hot saline water were met with, below the level
of the sea, in the neighbouring mines of North Roskear and North Crofty,
and also recently at Cook's Kitchen, both situated on the same cross course.
These waters have not been analysed.
'(e.) A hot spring yielding waters possessing the same general charac-
teristics as those from Wheal Seton, formerly issued at the Wheal Clifford *
mines in the 235-fathom level, or at a depth of 1,320 feet below the sea. It
will be seen, by referring to a map, that in this case a well-defined cross
course can be continuously traced in a north-westerly direction from the
immediate vicinity of the spring to the sea at Tobban Cove."
The following remarks on Wheal Seton, by the same authority, are worthy
of consideration :-
"It would be impossible to ascertain the precise conditions under which
springs of this description have been produced; but the accompanying ideal
sketch may perhaps assist in rendering intelligible what would appear, in
the present state of our knowledge, a not improbable explanation of their
origin.
"The plan A B C D (Fig. 57), being that of the cross course, is seen to
=A=
-S-
iliki
흡수
​Sea Level
C
Fig. 57.
extend through both Granite and Clay-Slate to the sea. From the close con-
tact of its surfaces, the presence of clay, and from other causes, this fault is
supposed not to be uniformly permeable by water, which can only follow
the circuitous passage, abcd. In this way it penetrates to depths where
* Of the water of the Clifford Amalgamated mines the following analysis was given by the late Dr.
W. A. Miller, and published as "Chemical Examination of a Hot Spring in Wheal Clifford, Cornwall,"
in the "Report of the Thirty-fourth Meeting of the British Association," &c., held at Bath, September,
1864. The waters issued at a temperature of 125° F., and at a rate of 150 gallons per minute.
Sp. gr.=1.007. The saline constituents were found by evaporation to amount to 646′1 grains
per imperial gallon, consisting of:-
Chloride of lithium
""
potassium with a little chloride of cæsium
sodium
magnesium
calcium
Sulphate of calcium
Silica
Oxides of iron, alumina, and manganese
26.05
14.84
363.61
8.86
216.17
12.27
3.65
minute quantity
645'45
CHAP. III.]
THE FILLING OF FISSURE VEINS.
369
reactions take place, which, although not entirely in accordance with the
results of daily experience in our laboratories, can, after the investigations
of M. Daubrée, M. de Sénarmont, and others, be readily understood.
"By the action of sea water on silicate of calcium, silicate of sodium and
chloride of calcium may be produced. The sulphate of sodium of the sea
water will be decomposed by the chloride of calcium, with the production of
sulphate of calcium and chloride of sodium. The decomposition of clayey
matter by common salt may produce chloride of aluminium and silicates of
sodium, while the magnesium of the chloride of magnesium may be replaced
by calcium; lastly, a portion of the potassium in the sea water appears to
have been replaced by the lithium of the Granite."
All this points, of course, to the hypothesis, that veins are filled by saline
water percolating through the more or less porous rocks, and slowly finding its
way through the small fissures, and the larger cracks, which by various dis-
turbances have been, through many ages, formed in the strata constituting
the surface of our planet. This water may have been derived from the sea,
which holds mineral matter in solution; or, it may have been merely the
surface waters, charged with carbonic acid or atmospheric air, dissolving
from the soil, soluble salts, which were again deposited by the operation of
a force, acting from the surfaces of the fissures, which we have already
called surface-force.
It is interesting to find Pryce saying: "We may reasonably infer that
water, in its passage through the Earth to the principal fissures, imbibes,
together with the natural salts and acids, the mineral and metallic particles
with which the different strata are impregnated, and, meeting in those
fissures matters which have nearer affinities with the acid, of course dis-
engage it, in whole or in part, from the metallic or mineral matter which
it held dissolved, and which on being so disengaged by the natural
attraction between its parts, form different ores more or less homogeneous,
and more or less rich, according to the different mixtures which the acid
had held dissolved and the nidus in which it is deposited. The acid, now
impregnated with a new matter, passes on, till, meeting with some other
convenient nidus, it lodges in that, and thereby acquires a fresh impregna-
tion, perhaps at last totally unmetallic, or, for want of meeting with a
proper nidus, appears at the surface weakly or strongly tinctured with those
principles it had last imbibed."
Though this passage is of necessity marked by the chemical knowledge
of the day, it shows that Pryce considered that the principal contents
of veins—particularly the ores-might be introduced into the fissures by
means of solutions which percolated through the enclosing rocks, and that
then the various substances in solution arranged themselves in the fissures
according to their affinities. He remarks on the occurrence of even small
parts of lodes, containing several different kinds of ore, separated from each
other by quartz, clay, and other substances, and asks how this could have
been effected "but by the agency of water to bring, and the power of
attraction to arrest, such and such particles, and deposit each in its proper
matrix or nidus." He particularly notices the various kinds of lodes, as
* "Mineralogia Cornubiensis," 1778.
B B
370
[BOOK II.
THE FORMATION OF DEPOSITS.
distinguished by the miners according to their contents, pointing out the
difference between the backs, or upper parts, and the contents beneath. He
describes a great variety of the gossans, observing that "the tender red
gossan is very much inclined to produce copper ore, especially if the gossan
be springy, cellular, and of a very red colour, like a well-burned brick.
When it is thus, and spotted, and tinctured with green copper ore, like
pieces of verdigris, it does not often deceive the proprietors. So likewise
stones of blue or black copper ore, or of yellow ore having a black or purple
outside, are very hopeful to follow when mixed in this gossan."
Pryce carries his opinion of the possible alteration of lodes so far as to
suppose that they may even, in a few centuries, change their character so as
to be rich at one time and poor at another; mineral substances being trans-
ferred from one part of the lode to another, "according to the solution and
transmigration of their respective principles, which are deposited in some
other magnetic nidus, whose power of retention in process of time may be
again decayed, those principles again depart, and again be arrested ad
infinitum.” However little we may be disposed to agree with Pryce as to the
time within which he supposes such changes can be produced, still we must
allow him the credit due to the recognition of the possibility of change,
caused by alterations of the conditions to which the contents of lodes may
be exposed, an opinion considerably in advance of the views of his age.
Pryce was doubtless led to this remark from the prevailing idea amongst
miners that a considerable period is required to effect the filling of a vein—
a question about which there has been much misconception.
Dr. Fleitmann* has recently observed that the formation of mineral
veins is far from taking so long a time as is generally supposed. About two
years before writing he filled a ditch with common clay containing some iron.
Having had occasion to dig this ditch anew, Dr. Fleitmann noticed, to his great
surprise, that the clay had entirely changed its character and had become
white. Moreover, it was divided in all directions by fissures, from the 25th
to the 26th of an inch across, and these were filled with compact iron
pyrites. He therefore supposes that the oxide of iron in the clay had
been transformed into sulphate of iron, on coming in contact with water
containing sulphate of ammonia.
A few simple experiments will prove that, under certain conditions, the
deposition of metallic matter from solutions may be rapidly effected. The
process of silvering glass by the action of some kinds of organic matter on a
solution of nitrate of silver may be adduced. A little grape sugar or
aldehyde being added to an argentiferous solution in a glass trough, pure
silver is rapidly thrown down, and forms a film of perfectly white metal on
the inner surface of the glass. If to a similar solution of silver, a minute
quantity of the hyposulphite of soda be added, not sufficient to precipitate any
silver, and the vessel containing it be placed in darkness, a film of black
sulphide of silver will be slowly formed on the surface of the glass vessel
containing it. This film is exceedingly coherent, requiring the action of an
acid to effect its removal. Again, if a solution of sulphate of copper be
placed in an unglazed earthenware vessel, the solution will gradually filter
* "Rapid Formation of Mineral Veins." By Dr. Fleitmann. ("Cosmos-les-Mondes," March,
1883, p. 334.)
CHAP. III.] FRAGMENTS OF ROCK IN MINERAL VEINS.
371
through it. Some crystals of the blue-stone solution will form on the outside,
and at intervals, after the action has gone on for some time, and the pores
of the vessel become contracted by the deposition of some of the metallic
salt, small fibres of native copper may be observed to form. The beautiful
experiment of placing a stick of freshly-burnt charcoal in a solution of the
nitrate of silver, and the formation upon it of the most delicate arborescent
crystals of metallic silver, will be familiar to many. This is really only
another example of the manner in which mineral veins are formed. These,
it must be remembered, are not to be regarded as examples of the formation
of mineral veins by the influence of electric currents, which will be presently
referred to, but rather as evidences of the action of a peculiar force-not
cohesion-which is by many delicate experiments proved to be active on all
surfaces of solid bodies.
Werner, as we have already said, drew attention to the evidences o a
system of regular deposits in mineral veins, that formed next the rock being
the oldest.
M. Fournet,* and others, have observed that the extreme regularity
noticed by Werner does not always take place, remarking that when
the veins contain fragments of the adjacent rock imbedded in their mass,
the ore has, in preference, always attached itself around them, envelop-
ing them in a bed of greater or less thickness. Speaking of the regularity
of the substances filling some fissures, M. Fournet mentions that M.
D'Aubuisson notices a vein composed of differently-coloured beds of sul-
phate of barytes and fluate of lime, placed upon each other with so much
symmetry in all parts, that more could not be accomplished with a compass.
and ruler. M. D'Aubuisson observes that this structure is exactly that
which would have taken place if the fissure had been filled with a solution,
successive deposits from which had been thrown down on its sides, adding
that the section of some geodes, and some water-pipes, in which successive
deposits have been effected, present analogous facts.
The same author has presented us with a very interesting account of the
evidence which exists of the successive openings of the mineral veins in the
environs of Pontgibaud, where for five years he was director of the mines.
He shows that successive dislocations not only broke through the previously
consolidated contents of the lode, but also that the complicated fractures.
frequently extended into the adjoining country, forming branches. Chemical
deposits of different mineral substances, or modifications of such sub-
stances, are seen to characterise five of the six successive dislocations which
M. Fournet has been enabled to trace in these lodes, the sixth being marked
by the introduction of pebbles and sand from above, a continuation of that
which still covered the country in many places, and which is itself covered
by the lavas of the extinct volcanoes of Louchadière and Pranal. From this
latter circumstance the author observes, that there would be nothing
remarkable in finding the metalliferous veins cut or divided out by basaltic
dykes, a fact that seems to have occurred in the veins of Courgoul and
Saurier, on the south-east of the Monts Dorés. It further appears, that
ferruginous and calcareous deposits are now effected in the open spaces.
which may present themselves in these veins, “so that, if after working out
* Études sur les Dépôts Métallifères." (D'Aubuisson, “Traité de Géognosie," tome iii.)
BB 2
372
[BOOK II.
THE FORMATION OF DEPOSITS.
the lode; the galleries be left shut during a long series of years, and the
mass acquire a certain compactness from successive infiltrations, new
workings could be carried on upon the siliciferous and calciferous hydrates
of iron. The attle, or broken rubbish, is even found to be cemented by
very compact ores of this kind, the mammillated surfaces of which have
sometimes the same appearance as some of the hydrates of iron of old date."
The recent formation of Pyromorphite (phosphate of lead) has been
already noticed, rarely, but occasionally, especially in the mines of Cum-
berland and of Scotland. Mimetite (a term derived from the Greek for
imitator, this species so nearly resembling pyromorphite) is found coating
other minerals. Vanadinite (so called from vanades, one of the synonyms of
the Swedish Venus), vanadiate of lead, is constantly found amongst the old
heaps, at the High-pirn of the Susannah mine, at Wanloch Head, on common
and cupreous calamine, and sometimes on galena. Numerous other
examples could be given of the comparatively recent formation of metallic
minerals, many of them taking place on the surface, and under the eyes of
the observer. One or two relating to copper will alone be mentioned. At
St. Agnes, as at several other shipping ports in Cornwall, piles of copper
were collected by the smelters in binns, and in the division appropriated by
each firm the ore was often allowed to remain for a considerable period
exposed to all atmospheric influences. Decomposition of the sulphide of
copper slowly takes place, and this is washed out of the pile by the rain.
This solution streams down the face of the cliff, and slowly, as evaporation
goes on, under the changed condition a new mineral is formed. Flowing
from the adit level at Perranporth, from Great Saint George's copper mine,
copper water issues. This was at one time utilised by making it flow over
scrap iron, and the copper precipitate was collected. Some dispute as to
the property put an end to this process. The copper water flowed on over
the soil and into the sand; the result has been the formation of oxides and
carbonates of copper with other salts cementing the sandy particles together.
It has been already shown that even attle, or broken rubbish, has been
found to be cemented with silicates and calciferous hydrates of the oxide of
iron-another proof that the conditions which have been active from the
beginning in producing those deposits, which we call mineral veins or lodes,
are equally active at the present time.
Up to this point the influence of cold waters infiltrating the soil or percolat-
ing the rocks has alone been noticed. A short space must now be devoted
to the formation of mineral lodes from the hot springs, which make the
rock fissures their channels for pouring out their waters on the surface.
There are no such examples in these islands, therefore the mineral lodes of
America must furnish the required examples. With no actual knowledge of
any mines beyond the United Kingdom, the author relies on the representa-
tions of those who have visited the mining districts of America and other
places where hot springs are poured out in abundance. He is especially
indebted to a paper by his friend Mr. J. A. Phillips,* from which the following
extracts are taken :-
* "A Contribution to the History of Mineral Veins." By J. Arthur Phillips, F.R.S., F.G.S.
(From the "Quarterly Journal of the Geological Society" for August, 1879.)
CHAP. III.]
DEPOSITS FROM HOT SPRINGS.
373
"Certain districts in California are remarkable for their hot springs; and
in some of the counties included between the 38th and 40th parallels, and
consequently north of the city of San Francisco, sources of this description
are of such frequent occurrence that, when viewed from elevated ground,
almost every valley is seen to be more or less occupied by wreaths of steam
rising from a flow of highly heated waters.
"The vents giving issue to these heated waters usually evolve carbonic
acid, which is frequently accompanied by various sulphurous gases; such
waters are generally alkaline, containing carbonate and sulphate of sodium,
as well as, occasionally, alkaline borates. They generally give rise to
abundant local incrustations of either silica or calcite, usually more or less
mixed with free sulphur. These deposits of sinter often extend, in nearly
horizontal layers, to a considerable distance from the orifices from which the
waters issue.
"When water is ejected from such vents in the form of steam and spray
only, while gases are abundantly given off and large amounts of sulphur
deposited, the aperture becomes a solfatara,
"One of the largest known deposits of sulphur in California occurs in
Lake County, a mile beyond the ridge which bounds Borax Lake on
its north-eastern side, and is many acres in extent. This Sulphur Bank,'
as it is called, is composed of a much decomposed volcanic rock, traversed
by numerous fissures, from which gases, steam, and water, either in the form
of spray or of vapour, constantly issue; and upon and throughout the
entire mass sulphur has been deposited in such large quantities that,
at a short distance, the whole appears to consist of that substance. In the
immediate neighbourhood of this solfatara are springs which give off
carbonic acid, and of which the waters contain carbonates of sodium and of
ammonium, chloride of sodium, borax, &c.
"In the year 1866 I visited Borax Lake and the neighbouring Sulphur
Bank in company with Dr. R. Oxland, of Plymouth, who was the first to
call attention to the presence of cinnabar in the sulphur from this locality;
and in 1868 I published, in the Philosophical Magazine,' a paper advo-
cating the probability of certain mineral deposits having been the result of
hydrothermal or solfataric action.*
"For some years subsequent to my visit this solfatara was worked as a
source of sulphur only; but during these operations so large an amount of
cinnabar was discovered, both in the decomposed basaltic rock and in the
cretaceous strata through which it has been erupted, as ultimately to lead
to the opening up of the cooler portions of the Sulphur Bank as a mercury
mine. This has long yielded large quantities of quicksilver, and affords
a striking and instructive example of a recently-formed mineral deposit
resulting from agencies still somewhat actively in operation." Mr. Phillips
collected, not only specimens of this cinnabar, but also a specimen of a
thin section of recently-formed quartz, from the face of a fissure in the
decomposed basaltic rock.
"Many years since Dr. Oxland found a notable amount of silver in the
"Notes on the Chemical Geology of the Gold-fields of California." By J. Arthur Phillips.
("Phil. Mag." 1868, vol. xxxvi. p. 321.)
374
[BOOK II.
THE FORMATION OF DEPOSITS.
sinter-like deposit from a hot spring in the county of Colusa; and Professor
Whitney, previous to 1865, had been shown at Clear Lake some peculiar and
interesting specimens of water-worn cinnabar, enclosing specks of gold, said
to have been found near Sulphur Springs in the same county of Colusa.*
"Steamboat Springs, in the State of Nevada, are situated near the base
of a volcanic hill seven miles, in a direct line, north-west of Virginia City
and of the famous silver mines on the Great Comstock lode.
"The rock at this place is traversed by several parallel fissures, which
either give issue to heated waters or simply throw off clouds of steam. The
most active group of these crevices comprehends five parallel longitudinal
openings extending, nearly in a straight line, for a distance exceeding a
thousand yards; their general direction is nearly north and south, and all of
them are included within a zone two hundred yards in width. These crevices
are sometimes filled with boiling water, which overflows in the form of a
rivulet; while at others violent ebullition is heard to be taking place at a
short distance below the surface.
"These fissures are lined with a silicious incrustation, which is being
constantly deposited, while a central longitudinal opening allows of the
escape of gases, steam, and boiling water.
"The Great Comstock lode is, as before stated, situate in a volcanic district
seven miles south-east of Steamboat Springs, has a nearly similar orienta-
tion, and is enclosed between walls of diorite on one side and of propylite
on the other. This vein, of which the gangue is chiefly silicious—although
calcite is also sometimes present-was first attacked by the miner in the
year 1859, and since that time the mines worked have yielded silver and gold
to the estimated value of above £60,000,000.
"The temperature of the waters issuing from mines worked upon the
Comstock lode has always been somewhat high, but it was not until they
had attained a very considerable depth below the surface that the
workmen first became inconvenienced by extraordinary heat.
At their
present (1883) depth (2,660 feet) water issues from the rock at a tempera-
ture of 157° Fah. (70º C.); and, according to Dr. John A. Church, of Ohio,†
who has recently published a valuable paper on the heat of the Comstock
mines, at least 4,200,000 tons of water are now annually pumped from the
workings, at a minimum temperature of 135° Fah. He also estimates that
to elevate such a large volume of water, from the mean temperature of the
atmosphere, to that which it attains in the mines, would require 47,700 tons.
of coal. In addition to this, however, 7,859 tons of coal would, he calculates,
be required to supply the heat absorbed by the air, which passes along the
various shafts and galleries through which it is diverted for the purpose of
ventilation. It follows, therefore, that to develop the total amount of heat
necessary to raise the water and air circulating in these mines, from the mean
temperature of the atmosphere to that which they respectively attain, 55,560
tons of coal or 97,700 cords of firewood would be annually required."
The same author, in his work already referred to, gives a table of the
*
Geological Survey of California," vol. i. p. 92.
"The Comstock Lode; its Formation and History." By John A. Church, G.M., Ph.D. New
York: 1879.
CHAP. III.]
HEAT OF THE COMSTOCK LEVEL.
375
temperatures of rock water and air, from which it is instructive to make a
few extracts.
The temperature of the air at the surface varied, in June, 1877, from
88 to 93 deg.
At 1,100 feet
Rock.
128
2,000
Air.
II2
""
108
""
""
""
""
2,135
106
""
""
2,200
""
•
139
""
1101
2,400
2,480
•
141
""
""
•
152
""
""
2,670
•
""
155 ""
""
He likewise remarks that "the rock is not uniformly heated through-
out, but contains restricted areas, where the heat rises very much above or
sinks below the temperature of the surrounding mass." Again: "These cold
areas complete a well-linked chain of heat phenomena, extending from rocks
that are sensibly cold to the touch, and may not have a temperature above
60° Fah., through rocks that have the average atmospheric temperature, and
those which are as hot as surface rocks ever become in Nevada, to those
which have a temperature of 157° Fah.”
Dr. J. A. Church thus sums up the result of all his observation: "In brief,
the phenomena of the Comstock lode do not admit even the possibility that
the heat encountered is a remnant of ancient eruptive heat. That oxidation
is not the cause of the heat is proved by inspection of the rocks." He
refers the heat measured to kaolinization, "by which the anhydrous aluminic
silicate of the feldspathic and amphibolic rocks . . . . is altered to Porcelain
clay by combining with water. The water changes from the fluid to the
solid condition, and in doing so, the general law of solidification is obeyed,
the molecular motion which had maintained its state of fluidity becoming
sensible as heat."
As attention has been drawn to a consideration of the heat of mineral
deposits, and of the subterranean temperatures measured, this appears to
be the proper place to give some attention to the thermometric measure-
ments made, in some of our deep mines, in this country, the most important
observations having been made in Cornwall.
Mr. R. W. Fox instituted a set of observations in the deep Cornish mines.
The mean difference of temperature measured was as follows. The depth of
constant mean average temperature was taken at 50 feet below the surface.
At 59 fathoms below the surface the temperature was 60 deg. Fah.
132
239
""
""
""
""
""
70
80
""
This shows an increase of 10° at 59 fathoms, or of 1º in 35'4 feet; 10° more at
73 fathoms deeper, or 1° in 43.8 feet; and of 10° more at 114 fathoms still
deeper, or 1º in every 64 feet of depth. With regard to those observations on
temperature, although we get a general mean upon which some reliance can
be placed, yet, in the state in which we find the returns at the present time,
they are comparatively of but small value. We discover a general rate of
increase of temperature with the depth, extending to the greatest depth
observed, but we also discover irregularities resulting from local action. A
very remarkable example of this is shown in the hot water flowing through
the hot lode of the late Clifford Amalgamated mines. On a previous page (211)
376
[BOOK II.
THE FORMATION OF DEPOSITS.
will be found a section of this lode and the Elvan courses near it, to which
the reader is referred (Fig. 22). One Elvan course comes to the surface, and
is then about 1,000 feet from the mineral vein, and another comes also to the
surface, and is seen about 250 feet on the other side. Three of these dykes
come together and cut the lode, where the hot water flows out. These Elvan
courses pass through the county for several miles, and send down a large
quantity of water into the mine.
The temperature of the eastern end at the 224-fathom level was
Water.
110 deg. Fah.
108
122
Air.
71 deg.
Do.
235-
81
•
"",
""
Do.
bottom of Davey shaft
110
>>
•
""
Do.
Do.
of the western end at the 280-fathom level
to the west of Garland's shaft at the same depth
126
I 20
""
··
""
128
118
>>
•
•
That this high temperature was due to chemical influences going on in the
proximity of the waterflow appears to be proved.
Some years since a mass of ochrey matter was sent to the author from a
remote part of these mines, which was taken from 20 or 30 fathoms below the
adit. A very large deposit had been discovered. It was found to be de-
composed iron pyrites, and the water flowing through the Elvan courses
derived its heat from the chemical action of the decomposing iron pyrites.
The late Mr. Edward H. Hawke, one of the committee of those mines,
wrote: "In the levels of Clifford Amalgamated mines the thermometer
stood, as I have always heard, and fully believe, at about 100° Fah. before
the immense deposit of copper ore was taken away, and now the same levels
are cold enough to make the agent, when underground, wish for a great-coat
in walking through them."
In 1864, Mr. Warington W. Smyth read, before the British Association
at Plymouth, a paper "On the Thermal Water of the Clifford Amalgamated
Mines." His remarks are so much to the point that it is thought desirable
to quote them :-
"In the neighbourhood of Redruth, and situated mostly in the parish of
Gwennap, is a district equally remarkable for the high temperature of its
deep-mine workings, and for the enormous value of the copper ores extracted
from them within the last half-century. The constituent rock of this region
is mostly Clay-Slate or Killas, which, abutting against the Granite dome of
Carn-Marth, dips away from that hill towards the east, and has not been
unbottomed in the deepest mines. . . . although there can be no reasonable
doubt that the Granite would be found occurring again beneath it. The Clay-
Slate is intersected by dykes of Granitic porphyry coursing in an east and
west direction; by lodes or mineral veins having, on the whole, a very
similar line of strike; and by cross courses or non-metalliferous veins, running
north and south."
Mr. W. W. Smyth then refers to Mr. W. J. Henwood's observations
made in 1843, "On Subterranean Temperature in the Mines": "Thus at
Poldice, about a mile north of the United mines,* and upon parallel lodes,
the water flowing out of the lode at 184 fathoms or 1,104 feet deep, exhibited
a maximum temperature of 100° Fah.; at the Consolidated mines, at
294 fathoms or 1,764 feet, the water in a level in the south vein was
* United mines and Consolidated mines were subsequently called Clifford Amalgamated mines.
CHAP. III.] TEMPERATURE OF SUBTERRANEAN WATERS. 377
95.5° Fah. At the United mines-in the western part or Poldory—a large
gush of water from the Elvan course, at 184 fathoms or 1,104 feet, reached
90° Fah.
In the eastern portion of the United mines, called 'Ale and
Cakes,' a moderate spring flowing from the rock, between the great south
lode and the old lode, at 195 fathoms deep, showed a temperature of 93.5°.
A stream cut in the rock adjoining the great south lode in the eastern end,
at 210 fathoms or 1,260 feet deep, was 92°.
"In the year 1839, a perpendicular shaft having been sunk to a greater
depth than that at which the old lode of the United mines had hitherto been
worked, a cross-cut was driven from it at the 180-fathom level (about 225
fathoms deep) which intersected the vein at a spot about a quarter of a mile
farther west than the points at present in operation, and here a large feeder of
water was encountered of so much higher temperature than had before been
observed that it was at once termed a ‘hot spring,' and the lode the 'hot lode.'
"The shaft being deepened by successive stages, it has been found that
at each deeper point at which the chief flow of water has been seen, it
has been prevented by the excavations from rising farther upwards, and has
shown a marked accession of temperature. In 1855 I found it welling up
abundantly from a fissure extending along the north wall of the lode at
about 1,510 feet from the surface, with a temperature of 114° Fah. . . . . At
present (1864) the bottom level, which, at the adit or datum line is 45 fathoms
from the surface, is 275 fathoms or 1,650 feet deep; in its end the lode was
narrow and very impervious to water, but a little rill trickling from it showed
a temperature of 121°, whilst a larger feeder which fell from an upper
working was 119° to 120° Fah. The next level above, called the 225-fathom
level (below adit), is advanced farther eastward by some 70 fathoms; the
lode exhibited a good breadth of fine black-coated copper pyrites, and small
feeders of water issuing mostly from the north or hanging wall almost
scalded the fingers holding the thermometers, which marked 122° Fah.,
whilst the air in the last few feet was 112° and loaded with vapour.'
Mr. Smyth next informs us that "the amount of water delivered from the
Clifford Spring is estimated at 150 gallons per minute.
As regards
the increment of temperature, it is somewhat startling.
Between my
two last visits, made at intervals of nine years, on both of which I
carried down trustworthy thermometers, the point of issue of the hottest
water had been deepened 30 fathoms or 180 feet, and the temperature
was increased by 8° Fah. This would give 1° for 22 feet, whilst a
comparison with Mr. Henwood's observation at Poldory would give a much
higher rate. The same uniform rate of increase would bring us to the
boiling-point of water at an additional depth of from 1,440 to 2,000 feet.”
The evidence in favour of a constant increase of temperature with increase
of depth does not appear to be at all satisfactory. All the high tempera-
tures observed can evidently be accounted for by chemical decomposition of
one kind or another. At the same time there is no doubt that the increment
of heat in our deep mines points to a source of weak electrical action which
does its work. Mr. Henwood* gives a long list of the observed temperatures
"On_the_Temperature of the Mines of Cornwall and Devonshire," &c. By William Jory
Henwood, F.R.S., &c. 1843.
378
[BOOK II.
THE FORMATION OF DEPOSITS.
of "the water as it issued from the unbroken rock." It is impossible to
reprint those tables without sacrificing much valuable space. We content
ourselves therefore with the following abstract :-
MEAN TEMPERATURES AT NEARLY EQUAL DEPTHS IN THE GRANITE AND SLATE
Rocks.
Granite.
SLATE.
DEPTH.
Depth.
Temp.
Depth.
Temp.
Fathoms.
Deg.
Fathoms.
Deg.
Surface to 50 fathoms
25
52.67
30
55'9
50 to 100 fathoms
70
57.68
73
60.9
100 to 150 fathoms
•
132
65.0
125
68·14
150 to 200 fathoms
161
•
65.71
174
79'17
200 fathoms and beyond
•
240
76.15
241
89.4
Mean
94
60.35
116
68.89
No attempt to determine the difference between the mean temperature of
the Granite and Slate at various depths was made before Mr. Henwood
undertook the observations; he states that "the fact had been from time
immemorial known to practical miners." It is familiar to miners that the
largest streams of water flow through the cross veins—smaller ones through
the lodes—whilst but little issues from the rocks, whether Granite or
Slate. The working miners of Cornwall have long known that the tin
lodes at equal depths are colder than those in which copper ores occur.
Mr. Henwood furnishes also a table giving the
MEAN TEMPERATURE OF THE Rocks, CROSS-VEINS, And Lodes at NEARLY
EQUAL DEPTHS.
Rocks.
Cross-veins.
Lodes.
DEPTH.
Depth. Temp. Depth. Temp.
Depth. Temp.
Fathoms.
Surface to 50 fathoms
32
Deg. Fathoms.
55°32
Deg.
Fathoms. Deg.
31
53.76
29
54.83
50 to 100 fathoms
70
60.2
76
61.2
71
59.87
100 to 150 fathoms
134
69.66
115
64.75
126
66.88
150 to 200 fathoms
180
82.11 163
74'4
161
72.41
200 fathoms and beyond
235
87.9
220
88.75
246
88.57
Mean
III
67.55
99
64.82
III
66.04
MEAN TEMPERATURES, at NEARLY EQUAL DEPTHS, IN THE LODES WHICH CONTAIN
ORES OF DIFFERENT METALS.
TIN LoDES.
COPPER AND TIN
LODES UNITED.
COPPER LOde.
DEPTH.
Depth. Temp.
Fathoms. Deg.
Depth.
Temp.
Depth. Temp.
Fathoms.
Deg.
Fathoms.
Deg.
Surface to 50 fathoms
•
27
53.14
33
55.06
32
56.9
50 to 100 fathoms
71 59.15
72
61.16
74
61.8
100 to 150 fathoms
129
65.92
124
66.09
127
68.39
150 to 200 fathoms
181
64.83
171
81.75
172
78.33
200 fathoms and beyond
230
74:3
244
89.14
Mean
92
60.69
74
61.45
140
72.39
•
CHAP. III.]
TEMPERATURE OF DEEP MINES.
379
We know not what the temperature may have been in the past ages
when the lodes were in process of formation. The tables which have been
given will not allow of our drawing any conclusions which bear on the
formation of mineral lodes. They indeed prove little beyond the fact that
there is general increase of temperature as we descend into the Earth, and
that the increase is in a slowly diminishing ratio. We have already seen
that the very high temperatures of the Comstock and other lodes in
America is by Dr. J. A. Church referred to the conversion of felspar into
kaolin. The decomposition of iron pyrites in the United mine, and those
mines adjoining it, has been proved to be one source of heat. No support
is given to the hypothesis of deep subterranean heat. As far as man has
been enabled to measure the temperature, the only conclusion at which we
can arrive is, that local causes alone are active in raising the temperature
of the rocks. The measure of heat in Artesian wells is not satisfactory. The
flowing of hot water from the deep borings, mixing with the cooled water of
the upper portion of the bore-hole, leads to a modified result.
The well at Grenelle, where the temperature was observed by Arago, was
at 1,794 English feet from the surface, and at 1,675 English feet below the
sea-level, 82° Fah., or 1º in every 54.72 feet was measured.
For the well at New Salzwerk, in Westphalia, Humboldt gives the depth
below the sea-level at 2,052 feet, and from the surface 2,285 feet; here the
temperature was 91°, or an increase of 1º in 55 feet.
Q
The well at Mondriff, in the Grand Duchy of Luxembourg, at a depth of
730 metres gave an increase of 1º in every 57 feet.
о
At Monkwearmouth, Professor J. Phillips gives the depth of 1,497 feet
below the sea-level, and states the heat to increase 1º in every 59.36 feet.
At Duckinfield, Mr. Hopkins gives the result of an examination made to
the depth of 1,330 feet, as showing an elevation of 1º in every 65 feet.
Mr. R. W. Fox gives the following as the result of observations made in
three deep mines:-
Tingtang 630 feet
1068
""
Wheal Vor 834,,
Poldice
1254 "
864
1056
""
""
Temperature 68 deg. Fah.
82
I in 20 feet.
""
""
""
69
""
79
""
""
I 42
""
""
80
99
I 12
""
""
I
21
""
The author has himself measured the temperature at the bottom of
Tresavean 352 fathoms from the surface, in the sump 98°, in the Granite rock
100º. A remarkable condition presented itself in this mine which must not
be allowed to escape attention. The copper lode in the Granite penetrated
the rock very near its junction with the Clay-Slate, as a well-defined fissure
lode, to the lowest level. Then the lode ceased to show well-defined walls,
at about 310 fathoms below the adit, and the copper was disseminated
through the Granite in a very singular way. The agent of the mine
drew attention to a phenomenon observed by him. The Granite containing
copper pyrites was at this depth exceedingly hard and coherent, so that
much force was required to break it out. The broken masses being sent
to the surface gradually cooled, and after a little exposure became so
far changed that, with a slight blow, it fell to pieces. The cause of this
380
[BOOK II.
THE FORMATION OF DEPOSITS.
appeared to be the variations in the rate of cooling amongst the constituents
of the rock. On placing some of the decrepitating pieces in an oven, and
bringing them up again to a temperature of 100° Fah., they became as hard
as they were in the bottom of the mine, clearly proving that the disinte-
gration of the mass was due, mainly, if not entirely, to the amount of
contraction produced in the copper ore and earthy crystals of the rock upon
a loss of heat.
The composition of the water from a warm spring at Wheal Seton, sup-
posed to be derived from the sea, has been determined by Mr. J. A. Phillips,
and an analysis also, by the same chemist, of the hot water which issued
from the bottom of Clifford Amalgamated mines, and which is exceedingly
rich in lithium (see p. 368). The conclusion to which we arrive after what
has been stated, is, that the heat detected in these waters is of local origin,
and it will add to the interest of the inquiry if two other analyses of the waters
of deep mines, made by Mr. Phillips, are given. The first of these was from
the 212-fathom level in the Phoenix mine, near Liskeard, issuing at a
temperature of 65° Fah.
WATER FROM PHOENIX MINE.
Solid matter 2130 gramme per litre, or 14'91 grains per gallon. Sp. gr. =1'0002.
ANALYTICAL RESULTS.
Carbonic acid.
Sulphuric acid
Silica
Chlorine.
Copper
•
Manganous oxide
Ferrous oxide.
Lime
Alkaline chlorides
Potassa
•
Soda
Ammonia
Nitric acid
•
Grains per gallon.
I.
II.
4.64
4'97
3.07
3.01
2.13
2.17
1.64
1.58
06
.06
*03
'03
•29
*32
*99
II 49
1'02
11.33
*90
•87
3.84
3.81
ΟΙ
ΟΙ
•I I
•II
The second water examined was collected at the 302-fathom level at Dol-
coath mine, near Camborne, which formerly produced large quantities
of copper ores. The Dolcoath lode has in depth gradually given place to
tin ore, and it is at the present time the most productive tin mine in the
United Kingdom. At the bottom of this celebrated mine a very remarkable
change has been observed in the character of the rock. The Granite has
become considerably softer, and less coherent, and at one place a layer of
stratified rock, containing two very thin bands of black tin, has been opened
out and traced for more than a hundred yards. This stratum assumes all the
characters of a recently deposited bed, and might easily be mistaken for a
new Oolitic formation. The water analysed was collected from the roof of a
short cross-cut in Granite, 25 fathoms east of the engine-shaft and 15 feet
south of the main lode. The water issued in considerable quantities, at a
temperature of 92° Fah.; and a large portion of the upper parts of the vein
had been removed by stopeing.
CHAP. III.]
HOT SPRINGS IN MINES.
The following are the results obtained in grains per gallon :-
WATER FROM DOLCOATH.
Solid matter 46.97 grains per gallon. Sp. gr.=1'0007.
ANALYTICAL RESULTS.
Grains per gallon.
I.
II.
Carbonic acid.
4'12
4.05
Sulphuric acid
9'13
9.06
Silica
2.06
2.II
Chlorine.
13.34
13°34
Arsenic
trace
trace
•
Alumina.
'03
*03
Ferric oxide
•31
•31
Manganous oxide
'04
⚫04
Copper
•
'05
*05
Lime
7.28
7.20
Magnesia
trace
trace
Alkaline chlorides
29.34
29.48
Potassium
I'92
I'93
Sodium
10'09
10'14
Lithium.
trace
trace
Ammonia
'02
*02
Nitric acid
•12
•12
381
Pryce long since remarked that different jets of warm and cold water
occur in some of the Cornish mines within short distances of each other. A
remarkable instance of this has recently been observed in Cook's Kitchen
mine, near Camborne. Mr. William Thomas favours us with the following
account of those springs :-
"On testing the temperature at the bottom of the mine I found the ther-
mometer to read several degrees higher than Captain Josiah Thomas's at
Dolcoath. The air in our 345 end east was 90º. This end is 13 fathoms from
a winze and 30 fathoms from shaft, as the following sketch (Fig. 58) shows:
The water comes almost
SHAFT
FMS
345 FMS LEVEL
Fig. 58.
WINZE
43 FMS
LAST
entirely from the bottom
of the level, and I could
not manage to separate
the hottest water from the
cooler. Placed in a run-
ning stream in the bottom
the thermometer read, in two different places about 7 or 8 fathoms apart,
between 94° and 95° Fah. Being in the same neighbourhood and acting on
the same lode, at nearly the same depth as Dolcoath, there must be some
special reason why the temperature varies so greatly. In sinking our last
two lifts-say 25 fathoms-we have had a great change in the structure of
the lode, consequent upon the junction of Chapple's and Dunkin's lodes at
the 320. There appears to be a change in the character of the ground in
many respects similar to that which has been described as existing at the
bottom of the neighbouring ground at Dolcoath. It will be interesting to
watch the progress of sinking in these mines, and to note the changes, if
any, which occur as the depth from the surface increases. During the last
two years the action of the water in the bottom of Cook's Kitchen has been
382
[BOOK II.
THE FORMATION OF DEPOSITS.
very interesting. A rough cross-section of the mine will show you more
exactly than my words, and I therefore give the following figure :—
S.
LODE
SOUTH
42 FMS LEVEL
DUNKIN'S LODE
320/FMS
345 FMS
CHAPPLE'S
LODE
ENDEY'S LODE
Fig. 59.
N.
"The south lode has never
been seen in this mine except
at the 42, and we are now cross-
cutting towards it at the 320,
our present bottom being 345.
I think the change of ground
before referred to has enabled
the water pent up in the south
lode to find its way through a
junction at a point up to the
345 on Chapple's and Dunkin's.
The hot water comes from the
bottom of this level. Hence
we get a higher temperature
than we ought, but this can only
be temporary, for as the south
lode is drained the temperature
will naturally decrease. I believe
that this mainly, if not wholly,
accounts for the heat. The
oxidation of freshly exposed
mineral ground is said in some cases to cause an increased temperature.
Our lode in the south part (the part driven on) is a very promising asso-
ciation of some 3 per cent. tin oxide with quartz and iron carbonate, also a
little fluor, iron oxide, and 'prian.' So far as I can see there is nothing in
the composition of the lode itself to cause increased heat by oxidation.”*
It may not be quite apparent to some of our readers why so much con-
sideration has been given to the increasing temperature of the Earth. This
question is best answered by a quotation from De la Beche :-
"Upon the hypothesis that the heat at the bottom of fissures is supposed
to be sufficient to vaporise water flowing into them, waters slowly oozing out
of the pores and interstices of rocks into cracks, heated at their surface by
the ascent of vapours close to them, would have a tendency to be vaporised
before they could trickle downwards towards the more heated parts of the
fissures. Consequently mineral substances which they held in solution,
and which could not be carried in vapour with the steam at the same heat,
would be deposited on the sides of the fissures."
Mr. R. W. Fox has observed respecting a fissure under these conditions :
"The difference of temperature in the higher and lower parts of the crack
would cause ascending and descending currents of water, and substances
which are soluble at high temperatures, and insoluble when such tempera-
tures are reduced, would be deposited as the water ascended and became
gradually cooler.” †
* Mr. William Thomas says in a subsequent note: "You have undoubtedly seen the report of Captain
Josiah's recent observations on temperature in deep mines, making an increase of 1° for 981 feet depth, as
against 1° in 50 to 65 feet, as previously recorded."
+ "Royal Cornwall Polytechnic Reports," No. 4, p. 108.
CHAP. III.]
TEMPERATURE OF SLATE AND GRANITE.
383
This hypothesis necessarily involves a much higher temperature than that
indicated in the hot springs of the mines of this country. Some of the
hot springs of California, as the quotations from Mr. J. A. Phillips, already
given, have shown, certainly issue to the surface at high temperatures-157°
Fah. to 135° Fah. are named. At such temperatures the water dissolves sili-
cates, and these are deposited in the cracks through which it flows out to the
surface. It is not improbable but that at remote periods similar conditions
to those now found in America may have prevailed in this country, and
may have been active in producing some of the conditions which we now
discover in mineral lodes.
To obtain a fair approximation-with due allowance for modifying causes
-to the rate of the increase of heat with the depth, in Cornwall and Devon,
to those lines which mark curves of equal temperature beneath the Earth's
surface, and to which Professor Bischof has given the name of chthoniso-
thermal, would appear to be now the proper object of inquiry; one, however,
which can be only accomplished with great care, for water rising up in
the lodes, or percolating through the pores and crevices of the adjoining
rocks, would always modify the temperature of particular portions of a mine.
Mr. Fox, in noticing the fact observed by Mr. Henwood and himself,
that the Granite in the Cornish mines is found to be less warm at equal
depths than the Slates, remarks that he had long attributed this difference
to the facility afforded by lodes, as compared with rocks, and of Killas
(Slates) as compared with Granite, for the ascending and descending currents
of water.
The same authority considering that the high temperature of the lowest
parts of deep mines is, in a great degree, independent of accidental or
extraneous causes, not existing in the Earth itself, and that it is more often
diminished by them than the reverse, caused thermometers to be placed at
different depths in the rocks of Levant mine and in the Consolidated mines
(Gwennap), the results of which were that the deeper thermometers (4 feet
long) stood at a higher temperature than other thermometers placed near them
and buried only 1 inch in the rock. In Levant mine the long thermometer
in Granite, at 230 fathoms from the surface, and 200 beneath the level of the
sea, stood at 80°, while the short thermometer rose only to 78.5°. Placed
in Slate in the same mine at about 190 fathoms under the sea-level, and
4 feet from the lode, the former indicated 78° and the latter 72:59. Results
of a similar kind were obtained in Consolidated mines (Gwennap), with the
additional information that, in a cross-cut in which the experiments were
made, the temperature increased towards the lode, being in the latter much
more considerable than in the cross-cut, an effect which Mr. Fox attributed
to the greater facility afforded by it to the ascent of currents of hot
water.
In Tresavean mine Captain Oates obtained the following results—experi-
menting at the request of Mr. Fox-with a thermometer buried 2 feet
10 inches in the rock, and another 1 inch under the surface of the rock at
the two stations *
*( Report of some Experiments on the Electricity of Metallic Veins and the Temperature of Mines.”
("Report of British Association for 1837," pp. 133-37.)
384
[BOOK II.
THE FORMATION OF DEPOSITS.
Depth in Fathoms
from
from
Surface. Sea-level.
In Air.
Experiments made
In the Rock.
No. I.
No. 2.
deg.
deg.
deg.
26
200
""
170 In the lode, rock do., "Killas" and three fathoms
from Granite
In Granite 15 fathoms north of lode and 40 fathoms 53°3
57'
52·8
77.2
76.
75'5
200
170
In do. Io fathoms from do.
•
77:7
76.
75.5
250
196
In lode contained in Granite and 60 fathoms from
"Killas"
a
}83-2
82.5
82.
262
85.5 .. 82.5
82.
208 In lode, do., in 7 fathoms from do., being the bot- 85.5
tom of the mine.
Sir Henry de la Beche supposes that fissures may have been opened
beneath great bodies of water, as the sea, admitting a steady flow of that
fluid through them. Under such conditions currents of ascending hot water,
and descending cold water, would be produced; the steam formed would
tend to rush upwards, and be converted into water when it arrived at
temperatures less than the boiling-point of water. The fissures would tend
to cooling by the entrance of cold water from above; but De la Beche
then remarks: "It will be readily seen that under the conditions the
rate of cooling would be so slow, that long periods of time would elapse
before any material change would be effected in the temperature of the
fissure, supposing even that the chemical effects which would be produced
did not materially influence any changes of temperature that might arise."
This eminent geologist says further: "We have abundant evidence whence
to infer that, since the consolidation of the Granite and Elvan, and indeed
of morè recent rocks, the area under consideration was beneath the level
of the sea, subject to oscillations that caused elevations and depressions,
some of which may have been accompanied by dislocations of the rocks."
The whole of these hypotheses are based on the idea that there is a uni-
form increase of heat from the surface towards the centre of this planet.
This assumption requires that, at a comparatively limited depth, the hardest
of the known rocks must exist in a state of igneous fusion. The results
obtained by the Astronomer Royal in the Harton Colliery* do not support
this view. In May, 1826, Sir George Airy commenced his pendulum expe-
riments for determining the mean density of the Earth at Dolcoath mine, in
Cornwall, but sundry accidents prevented his obtaining a satisfactory result.
Eventually, in 1854, new experiments were made in the Harton Colliery, and,
with the advantages of using the electric telegraph, the most satisfactory
results were obtained. The final results were :—
1211 feet of rocky and shaly beds gave a specific gravity
30 feet of coaly beds gave a specific gravity
Mean density of the Earth being proved to be
2.56
1.43
6.566
The value thus obtained was much larger than that obtained from the
Schehallion experiment by Dr. Maskelyne, and considerably larger than the
means found by the torsion-rod experiments of Baily.
When we remember that red hæmatite ore-the densest body in nature—
is never of a higher specific gravity than 5.3, it appears to carry conviction
"Account of Pendulum Experiments undertaken in the Harton Collieries for the purpose of deter-
míning the Mean Density of the Earth." By G. B. Airy, Astronomer-Royal. ("Philosophical Trans-
actions of the Royal Society," vol. cxlvi. 1856.)
CHAP. III.] BECQUEREL'S ELECTRICAL EXPERIMENTS.
385
to the mind-seeing that none of the rocks which in our mining operations
we have passed through approach to this specific gravity—that the centre of
this planet must be a dense hard mass to give for the whole a specific gravity
of 6.566.
M. Becquerel was the first to call attention to the influences of electricity
in producing some very remarkable chemical changes in mineral bodies.* He
remarks: "For a long time it could not be conceived how, with apparently
feeble electrical forces, strong affinities could be overcome in order to decom-
pose bodies and produce new combinations, it being considered that the
action of currents more or less energetic should always be employed. As
soon, however, as the electrical changes, which take place in chemical actions,
had been analysed, it became clear that the same end might be obtained
by employing weak voltaic currents. It can be readily understood, that
when any voltaic couple be plunged into a solution, which reacts on one of
the elements of this couple, the particles of the solution, the moment they are
brought into play by the operation of chemical action, are then-since they
are in a nascent state-in the most proper condition to obey the action of the
electric current produced by the couple."
d
M. Becquerel produced a variety of crystalline substances, such as the
oxides of many of the metals, and the sulphides of others, by the action of weak
electric currents. He employed a tube, Fig. 60, bent like an U with a plug
of moist clay, a, in the bottom, separating the solutions to
be acted upon in the two branches bc, into which a wire,
d, was introduced to form a voltaic circuit. The following
was the form of one of his experiments: "Some clay,
well divided and moistened with a solution of arseniate of
potash, was placed in the bend of the tube. On the side b
c arseniate of potash was placed, and on the side ỏ a solu-
tion of nitrate of copper. The latter penetrated readily
into the clay; a very slow reaction took place between the
arseniate and the nitrate, a circumstance favourable to the
crystallization of the arseniate of copper. At the end of
some time crystals resembling the arseniate of copper of
nature were observed in some of the open parts of the
clay." Many other examples of a similar change are
given by M. Becquerel, showing the influence of weak electric currents in
producing phenomena similar to those which we detect in our mines.
α
Fig. 60.
We have already alluded to the influence of electricity in laminating clay.
It is now desirable to describe a very conclusive experiment, proving that
miniature mineral lodes may be formed by the influence of this agency.
Masses of clay subjected to this action were found after some months to
have assumed the conditions mentioned by Mr. R. W. Fox. On the side next
the zinc plate of a voltaic pair distinct lines of cleavage, parallel to the
sides of the clay and the plate, or at right angles to the direction of the
current, presented themselves. These laminæ, on drying the mass, were
gradually contorted, and at length broken off. On the side next the copper
plate, instead of the laminated structure, a consolidation was observed of the
* Becquerel, "Traité Expérimental de l'Électricité et du Magnétisme," tome iii. Paris: 1835.
C C

386
THE FORMATION OF DEPOSITS.
[BOOK II.
mass, this consolidation appearing to take place in the direction of the current,
or very nearly so. The induration in many cases was very striking. In one
experiment made with great care upon a lump of clay weighing several
pounds, where the action was continued from July 4th, 1845, to January 20th,
1846, and then allowed to dry between the galvanic plates, the results were
so curious as to merit particular description (Fig. 61).
2
Fig. 61.-Electrical Experiment.
On the zinc side, z, to the depth
of 1 inch, there were distinct lines
parallel to the plate, not extending
from the top to the bottom of the
mass, which was 12 inches deep,
but after proceeding about 6 inches
down exhibiting a tendency to bend
inwards. Upon breaking the clay
open when dry, it was found that
c after proceeding towards the centre
of the mass, they again turned out-
wards, and formed indeed curved
lines, from one point of the zinc
plate near the middle, to its lowest
point. The consolidation on the
copper side c was very distinctly
marked, and the appearance was
that of a continuation of hard nodu-
lar masses along the lines of the vol-
taic current. This consolidation had evidently been produced by the drawing
of particles from the centre of the mass, in which a large hollow, a, was formed;
and this was found to be a portion of the very decidedly marked line of action
from the bottom of the zinc plate to the centre of the copper plate C, and
from that point again to the top of the zinc plate z. As these curved lines
approached the zinc side they were crossed and split by laminations, although
very distinctly continued. We have thus evidence afforded us of two distinct
forces in action, or perhaps it would be safer to say, indications of two lines
of power, along which the particles arrange themselves. It was found upon
close examination that the curved lines above described were formed by the
metallic copper and the carbonate of copper and zinc (sulphate of copper was
used on the side of the copper plate and muriate of soda on the zinc side).
Upon breaking the clay transversely the appearance of the mass was in the
highest degree interesting and instructive. From near the top on the zinc
side a dark space was seen to describe a line inclining from the horizon at
about the angle of 40°. When it approached the copper side it was gradually
bent back, and formed a curve to the bottom of the zinc plate. This curve
was formed, in parts near the copper plate, of laminæ of metallic copper,
whilst more distant from it, specks of carbonate of copper appeared which
were particularly confined to the marked space, and indeed represented an
artificial mineral lode.
A difficulty at present exists, which will no doubt disappear when
we have had the experience of further investigation. This is to account
CHAP. III.]
ELECTRICAL FORMATION OF VEINS.
387
for the arrangement of the particles of clay in parallel planes, according
to the order of the diamagnetic curves, and, of the disposition of the
metallic salts, and metal themselves, even of those which are not magnetic,
-zinc and copper,-along what appears to be the true circuit of the electric
current.
It was observed, very soon after the experiment just described was first
established, that the fluid on one side was elevated considerably above the
fluid on the other; this is the well-known exosmose, always observed during
electro-chemical action. But in this case the mass of clay was elevated on
the same side, and this went on increasing until the fluid was dried off. This
may have been merely mechanical, but the fact is curious in itself, and worthy
of notice, as it may lead to the explanation of some movements of solid
matter under circumstances of apparent difficulty. Other experiments have
proved to me the possibility of raising comparatively large masses of matter
by the agency of current force, or the dynamic power of voltaic electricity.
A number of nodules were formed in the clay in this instance, and it was
curious to observe, that all these concretions arranged themselves along the
line of the current. In nature they are mostly found in some given direction
parallel to each other; and, from the indications we have thus obtained, it is
probable that we shall find their order determined by some local electrical
influence.
A thin paste of plaster of Paris was placed between similar plates of zinc
and copper, which were excited by diluted sulphuric acid. This action was
kept up for about three months, and then allowed to dry off. On becoming
quite dry, it was found that the gypsum was laminated, to the depth of an
inch, on the zinc side and indurated considerably on the copper side.
An ordinary Bath brick used for scouring cutlery-a silicious Sandstone
-was placed between a zinc and copper plate, in a similar voltaic arrange-
ment to those already described, the current being excited by a solution of
salt (muriate of soda) on the zinc side and sulphate of copper on the copper
side. The lamination was very decided to the depth of more than half an inch,
from which to the middle the brick remained unchanged, whilst on the copper
side the general induration had taken place, as in the other examples. Copper
had passed through the brick, and it presented itself in the form of carbonate
on the zinc side, running across the lines of lamination. This brick had been
placed in the trough vertically; it was only on one side that the carbonate of
copper was seen, but it extended from a certain point near the centre of that
side, increasing in quantity towards the zinc plate, no trace of it being seen
on any part of the brick near the copper plate, except a thin lamina of it
between the plate and the Sandstone. As the lamina dried they became
very much contorted, and were gradually broken off from the mass.
A similar brick was placed horizontally between a copper and a zinc
plate, excited as before. After the action of about four months it was dried,
when it was found to have cracked from near the bottom of the zinc plate to
the top of the copper plate, separating into two nearly equal parts. This
fracture corresponded in direction very nearly with that observed in the
clay. On the zinc side the laminations extended to this line of fracture, and
the consolidation on the other side was also stopped by it. Running from
CC 2
388
[BOOK II.
THE FORMATION OF DEPOSITS.
end to end of the brick, about an inch within it on the zinc side, a line of
carbonate of copper was traced, above and below which some traces of lami-
nation were also marked out, as though this line of a metallic salt had
become the centre of a new set of influences. At each end of the mass a
great number of well-marked curved lines were observed, passing from the
plates on either side to the fracture. This indication of a movement of the
particles of the solid mass in determinate lines helps to explain the cause
of the dislocation. The general tendency of the current being along these
lines, lamination occurring on one side of the mass at right angles to them,
and consolidation on the other in the line of the current, we can easily
perceive that the line of dislocation must occur at a tangent to these curves
at that point where the two influences neutralise each other, which will be
found to be in a square mass from near one of its upper angles to one of its
lower angles, the exertion of electrical force being evidently across the imper-
fect conductor, but in lines of greater or less curvature, according to the
resistance its particles offer to the passage of the voltaic power.*
Cracks, or fissures, may therefore be produced by the action of weak
electric currents, and then filled with metalliferous salts by the continua-
tion of the same force. Mr. R. W. Fox's first experiment is very instruc-
tive. A basin was divided into two cells by a wall of clay. One cell
was filled with a solution of sulphate of copper, the other with a solution
of common salt. Into the copper solution was placed a piece of yellow
copper ore (pyrites). The arrangement was allowed to stand undisturbed
until all the fluid had evaporated. On breaking the wall of clay it was found
that lines of metalliferous deposit had been formed in the wall of clay at
nearly right angles to the direction of the electric current. The experi-
ments which have been named appear to prove that electricity may perform
a very active part in the filling of mineral lodes, and especially in pro-
ducing the orderly deposition of mineral matter, which is not unfrequently
found to occur.
The experiments of the laboratory clearly advance us many steps towards
the confirmation of the view promulgated, viz. that by the agency of elec-
tricity, some of the conditions similar to those which prevail in rock fissures
can be produced.
M. Becquerel considers that to a certain depth in the Earth a multitude
of electric currents exist with very different directions, the general result
of which would produce an action on the magnetic-needle. He considers.
these currents would be caused by the permanent communication, kept
up by means of numerous fissures, through which the sea water percolates
either to the metals of the earths, or alkalies, or to metallic chlorides, causing
the metals to take negative electricity, and the steam and other vapours
positive electricity. (It should be borne in mind that the difference in
temperature observed between the surface, giving a mean of 60° Fah., and the
temperature of such a mine as Clifford Amalgamated, with the heat at 120º,
is quite sufficient to establish the electric currents alluded to by M. Becquerel.)
*"Researches on the Influence of Magnetism and Voltaic Electricity on Crystallization and other
Conditions of Matter." By Robert Hunt, Keeper of Mining Records. ("Memoirs of the Geological
Survey of Great Britain," vol. i. 1846.)
CHAP. III.]
TERRESTRIAL ELECTRIC CURRENTS.
389.
One part of the Earth's electricity, he infers, would be carried into the
atmosphere by volcanic eruptions, and the other would tend to combine with
the negative electricity of the base, by passing through all the conducting
bodies which established the communication between the metals or their
chlorides, and the solid, liquid, or gaseous substances which filled the fissures.
Hence, he observes, a number of partial electrical currents would circulate
in the interior of the globe, producing electro-chemical reactions, of which
we cannot appreciate the whole extent, but which would certainly give
rise to numerous compounds. It is not easy to determine exactly what
M. Becquerel intends. It appears that he adopts the inference of M. Ampère
that the direction of the terrestrial magnetic meridian is due to the circu-
lation of electricity from east to west around the globe. It, in fact,
amounts to this. The Earth advancing to meet the sun feels, upon any
given point, the influence of the bundle of forces tied together in the solar
ray-light, heat, electricity, actinism, or chemical power-which produces
a current of electrical force, as we usually call it, but strictly speaking an
undulation, flowing westward from that point. Therefore a stream of
electrical force is constantly traversing this globe, from the east toward the
west, and the magnetic bar of iron-called the compass-needle-in obedience
to a fixed law, which compels it to place itself at right angles to such
electrical currents, takes its true position of north and south.
The question now presents itself, Do we find in the mines any condi-
tions similar to those by the agency of which chemical changes are brought
about in the laboratory? At the same time as the French physicist was
engaged in the experiments which have been named,* Mr. R. W. Fox,
of Falmouth, who had published the experiment already referred to,-of
making miniature mineral lodes in a basin,—was induced to inquire if such
weak electric currents as he had employed in his artificial arrangement
could be detected in the mineral lodes exposed in the operations of mining.
All who were ever brought into close communion with Mr. Fox must
have found in him an example of the true philosopher, who interrogated
nature in the purest spirit, seeking only to elicit truth. Yet it is to be
lamented that this gentleman was charged with having pirated from
M. Becquerel's book on Electricity the facts now to be described, and with
having appropriated them, without acknowledgment, as his own. Certainly
Mr. Fox commenced his experiments with weak electrical currents without
any information of what M. Becquerel had done, and it was only when
he had established certain facts that he became acquainted with the results
obtained by the French philosopher.
An hypothesis has been propounded that electric earth-currents select, in
preference to any other course, the lines of conducting power, which are, it
is supposed, constantly detected in mineral veins. It is, therefore, im-
portant to examine what has been effected towards the examination of this.
subject.
The existence of electric currents in mineral veins of copper and lead
was first observed by Mr. Fox in 1830 t; but he could not detect their
* Becquerel, “Traité Expérimentale de l'Électricité et du Magnétisme," tome iii. p. 295. Paris: 1835.
+ Philosophical Transactions," 1830.
390
[BOOK II.
THE FORMATION OF DEPOSITS.
presence in tin lodes, or in the earthy constituents of cross courses, or
in the rocks which such lodes traverse. Magnetism was imparted to
an iron bar by the influence of the current derived from a copper lode,
passed through a helix of wire coiled around a soft piece of iron. In the
same year this electrician discovered electric currents in the lead veins of
Logylas and Frongoch mines in Cardiganshire, but he could not detect them.
in either the South Mold or in the Milwr mines in Flintshire.* In 1833
Captain Barnetts detected electricity in the copper lodes of Wheal Vyvyan.†
In 1836-37 uncertain results were obtained by Mr. Fox in the lead veins
of Middleton in Teesdale, Durham. In the same year Mr. Pattison, at
the request of the British Association, investigated the electrical condition
of the Mountain Limestone and Sandstone of Alston Moor. The results
obtained were, however, exceedingly uncertain.§
In 1833 Mr. Petherick appears to have detected electric currents in the
copper lode of Connorree, in the Clay-Slate of Wicklow, Ireland.||
In 1841 the author of this volume, with Mr. John Phillips, of Tuckingmill,
Camborne, Cornwall, commenced a set of observations in the deep mines
around that town. The results were from time to time published in the
"Reports of the Royal Cornwall Polytechnic Society," from which the
following observations are copied :-
I
1. The whole of the researches included in this series were made in
East Pool copper mine, about 70 fathoms below the surface, on two lodes,
each underlying south, the north lode about 1 foot 6 inches in a fathom,
and the south lode 1 foot in a fathom (ie. where the experiments were
conducted). The lodes, it may be remarked, are very irregular in their
bearing and underlie, being most productive where they approach the
nearest to the perpendicular. It is often observed in this mine that bunches
of ore frequently lie between craggy walls, and Elvan is by no means
considered an unfavourable indication.
In pursuing these investigations several sources of slight error were
detected, which will be noticed as they occurred, in each set of experiments,
it being a point of great importance to secure other observers from the
inaccuracies to which they give rise.
2. The connection being made between the point 1 and the instrument
at a, the other wire was carried along the level (Fig. 62). On being taken
round the corner, marked 5 in the plan, the needle was deflected 15º,
although no contact was made with the lode, and when contact was made in
the north lode at 4, this deflection was arrested, the needle standing at 2°.
This was soon found to arise from the wire being in contact with a pile of
iron pyrites, 6, which giving out a positive current occasioned a deflection
of the needle to the west. When this was prevented, and close contact was
again made with the mass of ore at 3, the deflection of the needle indicated
a current passing from west to east. The greatest deflection we succeeded
in getting on this occasion was 45°. The interposition of plates of zinc or
* ( Geological Transactions Royal Cornwall Geological Society."
"London and Edinburgh Philosophical Magazine," 1833.
Reports of the British Association," vol. vi., 1838.
Ibid.
11 "London and Edinburgh Philosophical Magazine," 1833.
CHAP. III.]
EXPERIMENTS ON MINERAL VEINS.
391
of platina were found slightly to check the current, but never to change its
direction.
3. Connection was made, and broken, between the wire and the lode to
isochronous time, by the person producing contact, which not agreeing
with the oscillations of the needle, produced variable intensities of deflection
as aggravated or retarded by the difference in time of closing circuit.
4. Various points along the top or back of the level, between points a
and 5, were next tried. It was found wherever the contact was made with ore
that the needle was deflected as before, but no deflection could be excited
by any contact with the rock. This was most satisfactorily determined, in
proof of which may be quoted the remark of one of the miners who witnessed
the experiment, "The little thing knows ore, but doesn't know the country."
5. The galvanometer was now fixed at the point 6, and the permanent
connection made still near the point 1, being a distance of about 15
fathoms; the large coil was connected as before with the point 4. The con-
tact being made perfect at both ends, the needle of the galvanometer com-
pleted several entire revolutions, by the single impulse of the current passing
from I through point 6 to point 4 and back to point 1, or from west to east.
This being satisfactorily determined no further experiment was tried on
this occasion, owing to the extremely bad state of the air in the mine.
6. The galvanometer-one having a heavy single needle, and conse-
quently not very readily affected by feeble currents-was fixed at the point c,
and the connection made with a large mass of copper ore at 3. It was
noticed on this occasion that a deflection of 2° or 3° was produced between
the large coil of wire in contact with the damp rock and the sulphuret of
copper in the lode. To ascertain if the current was at all connected with
the rock, the coil was placed on a damp board, when the deflection was
found to be the same as before, clearly proving it to arise from the state of
the metal considered in its electric relation to the ore. Contact was made
by the large coil at 2, when the needle was deflected nearly 70°, but the
direction of the current was now from east to west.* This, being contrary to
the direction ascertained in former experiments, demanded the most rigorous
investigation. The current was analysed by the plates of zinc and platina,
but its direction still continued the same.
7. It was agreed that the observer should number aloud the oscillations
of the needle, in such order that the even number should indicate the
moment at which the needle arrived at its extreme deflection, raising or
lowering his voice according to the amount deflected. The object of this
was, that the person producing contact should make his own observations
on the nature of the contact, which arrangement enabled him, first, to dis-
cover, that contact with the ore of the lode was followed by an elevation of
voice, also that the presence of water, enveloping the end of the wire in
connection with the ore, was productive of greater deflection, but had no
effect when applied to the matrix of the lode or its sides.
8. Contact was made in many places along the cross course, between the
* Some time after this experiment was made, a large bunch of ore was discovered and worked out
behind the point of contact. Whether the mass of ore had anything to do with the direction of the current
was not proved.
392
[BOOK II.
THE FORMATION OF DEPOSITS.
north and south lode, without producing any deflection of the needle; but
as soon as the wire touched the ore, in the south lode at 6 the needle was
powerfully deflected in the direction, indicating a current flowing from west
to east, as in the former experiments.
9. The connections were made exactly as on the last occasion, and the
same results were produced, the direction of the current between the point
2 in the north lode and point 3 in the south lode being from east to west.
The large coil was now connected with that portion of the north lode lying
at the point 7 being carried round through the cross course, giving an
extended length of wire about 22 fathoms. The deflections were now 90°,
and the current from west to east, which is the greatest steady deflection yet
obtained with the heavy needle.
10. The large galvanometer and wire being fixed as in the last expe-
riment, the wire carried round to the eastern end of the lode and the
connection made with point 7, the current was found to be in the same
direction, from west to east. On this occasion the current was not allowed
NORTH LODE
WEST
4
1x8
a
XI
X5
X6.
SOUTH LODE
X3
1.
EAST
Fig. 62.-Electrical Experiment.
to flow through the whole of the wire on the coils, but small wires were
attached by binding-screws, which completed by its connection with the
galvanometer the electric circuit; this was found to increase the amount of
deflection slightly.
We now decided, by a repetition of the experiments, that from all the
points 1, 3, 4, 6, 7 the electric current was passing from west to east, but
between the point 2 and any of the others, the currents appeared to take a
different direction.
11. The large galvanometer was now fixed at d and the connection
made at 7, and with the point at 2 the current was indicated as from east to
west. Between the points 7 and the points 8 and 9 the current was evidently
from west to east, as it was also between any other two parts of the two
lodes tried at this time. It is not quite easy to explain the very peculiar
local disturbance which was found to prevail in close proximity with the
cross course at 2. But our experiments led us to the conclusion that the
current in these lodes is constant from west to east, the deviation found at
2 being no doubt dependent upon some peculiarly local effect.
Being desirous of endeavouring to effect chemical decomposition by the
agency of the electric currents flowing through the mineral lodes, we con-
CHAP. III.]
EXPERIMENTS IN PENNANCE MINE.
393
nected two wires with the points 7 and 2, these being chosen from the con-
venience of their situation. The ends pointed with platina wire were placed
in a phial which contained a solution of sulphate of copper. This being
arranged was left in the mine for a few days. When the phial was next
examined, one of the wires had been removed, no doubt by the curiosity of the
miners, but the wire which remained in the phial was sufficiently coloured
by copper, which convinced us we were not disappointed in our expectations.
The experiments in East Pool mine have been several times repeated with
the greatest care, but as the results have been invariably the same as those
detailed, it is deemed unnecessary to recapitulate them.
Some experiments were afterwards made at Pennance mine by Mr. R. W.
Fox, assisted by Mr. Joshua Fox. The following results, with which these
gentlemen kindly favoured us, are added to those previously obtained:-
Pennance mine is in Killas. It consists of two lodes bearing nearly
east and west (magnetic). One of these contains much arsenical and iron
pyrites; the other is a quartz lode interspersed with oxide of tin and
sulphides of copper and lead.
The more northerly lode, about 5 feet thick, dips a little towards the
north; it has been worked 16 fathoms under the surface. The other lode has
not been sunk deeper than 8 fathoms, 2 feet wide, and inclines towards the south.
All the experiments on the north lode gave currents through the appa-
ratus from east to west, and so, indeed, did the experiments of the south
lode, where they were tried, but they were less energetic.
In the east part of the north lode, at the six-fathom level, the current
caused the needle to revolve quickly after producing and breaking contact
a few times. Contact was made with the ore points by means of blocks and
screws-by plates of copper, zinc, and platina in succession-and also by the
points of the wires merely, but without any marked difference in the results
under these different circumstances. Nor was there any great variation in
the results, where the contact was made with different ores at the same
station; thus the positive current was not less energetic where the contact
was made with galena, as an ore point, than with iron pyrites nearly con-
tiguous to it. All these facts show the independent nature of these currents,
as it respects the apparatus, or accidental circumstances.
On connecting the back of the north lode immediately under the surface,
containing arsenical pyrites, with a portion of the same lode farther west, in
the six-fathom level, a maximum deflection of about 50º to 55º was produced
with copper wire folded up, and pressed into a bundle for making contact
with the ore points. There was a plate of zinc afterwards substituted for the
copper wire at the surface, from whence the positive current was derived
without any diminution of effect; and under these circumstances Mr. Fox
was enabled to impart magnetism to a horseshoe bar of iron with several
coils of copper wire round it, sufficient to act, though feebly, on a compass-
needle not very delicately poised. The stronger current below would
doubtless have produced a much greater effect.
In 1830 Mr. W. J. Henwood commenced a series of observations, and
continued them until 1840. "They extend," he says, "to every mining dis-
trict within the Duchy of Cornwall except those of Helston and St. Austell."
394
[BOOK II.
THE FORMATION OF DEPOSITS.
After a most careful examination of all the results obtained we feel very
reluctantly compelled to arrive at the following conclusions: In the first
place, Mr. Henwood was not sufficiently acquainted with electrical science
to carry out with accuracy a series of delicate observations on electricity.
In the second place, the peculiar characteristics of his mind were such as to
operate against his making satisfactory deductions from his experiments.
His tabulated results are numerous, but they are vitiated by his incorrect
system of examination. Frequently we find him establishing one pole of
his arrangement with a plate of copper and the other with a plate of zinc,
thus arranging a galvanic pair: from which electrical disturbance must
have been produced, quite independent of any result obtained from the
condition of the mineral vein.
This observer made some experiments on the influence of difference of
temperature which are of great interest, and appear to be strictly reliable.
The result of a long series of observations we find gives 57°1 per cent., from
the warmer to the colder point, and 42.9 per cent. from the colder towards
the warmer point. "We have," he says, "in the whole, thirty-three experi-
ments, on points of different temperatures; and in 22, or 66.7 per cent., the
currents have been towards the warmer, and in 11, or 33°3 per cent., towards
the colder point."
+
The objections raised to the electrical hypothesis are supported by the
following quotation. After the announcement of the discovery of electric
currents in the metallic portions of certain lodes, Mr. Christie* remarked
that some of the results might be due to the electric properties of the appa-
ratus employed, an objection which had also occurred to M. Becquerel.†
"The direction and quantities of electricity observed in rocks and veins are
probably due to the plates of different metals employed." Von Strombeck
entertained a similar opinion. Professor Reich used sometimes only plates
of copper, but occasionally he substituted a plate of zinc for one of them. §
Any one acquainted with the phenomena of voltaic electricity should know
that if upon the surface of a damp rock a plate of copper is placed, and
this is connected at some other point with a plate of zinc, electro-chemical
change will be set up on the surface of the zinc, and a current be established
through the wire, the circuit being completed along the moist surface of the
rock itself. This is, it should be remembered, merely the local action of a
single galvanic pair. The rocks themselves when dry are not conductors of
electricity, but moisten them and they become conductors.
The only
reliable arrangement for determining the electricity of a mineral lode is to
select a dislocated vein, to connect a clean copper wire with the ore on one
side of the rupture, by boring a hole in it, and securing the wire by ramming
in some powdered ore, and the other end of the wire, equally clean, in a
similar manner with the ore on the other side of the cross course or heave,
the two pieces of wire being connected through the galvanometer. If
this arrangement is properly made, and if electricity circulates in the lode,
its force may be measured off by the movement of the galvanometric needle.
Reports of the British Association," 1833.
*
+ "Traité de l'Électricité," vol. v. p. 171.
"Archiv für Mineralogie," vol. vi.
++
"Annals of Electricity," vol. ii.
"Edinburgh New Philosophical Journal," 1839.
CHAP. III.]
SUMMARY OF HYPOTHESES.
395
The result of the extensive series of experiments-carried out by the author
and Mr. John Phillips-went to prove that no electricity could be detected
in a copper or pyrites lode, unless it was to a greater or less extent under-
going decomposition. The electricity measured in these experiments gave
the rate at which chemical change was going on in the lode. If lead lodes
were decomposing, they indicated it by manifest electrical disturbance; but
rarely could any electricity be detected in a tin lode, simply because the
oxide of tin was not so liable to chemical change. In mundic lodes the
currents were often very strong. At Pennance mine, as stated, an experi-
ment was arranged between a pyrites and a copper lode, bringing the wires
to the surface and dipping them into a solution of sulphate of copper. By
this it was easy to obtain electrotype copies of medals; and ornamental
articles, coated with plumbago or gold, could be perfectly copied by the
direct action of the electricity derived from the lode. Electro-magnets could
also be made by the current, and occasionally a faint spark obtained.
These results, and many others of an analogous character, must be
regarded as the outshadowings of truths which are as yet but dimly seen on
the clouds of speculation.
To summarise the various hypotheses which have from time to time been
brought before the notice of the thinking miners. We find that Rösler,
Becher, and Stahl, Henkel and Zimmermann, in some form or other, adopt the
principles of the Stahlian philosophy which prevailed in Germany in the
eighteenth century, when the alchemical dogmas were still holding in a
somewhat altered form their place in the schools.
Von Oppel, who evidently originated the hypotheses accepted and
expanded by Werner, Erkern, Feachsen, Gellert, and others up to the time
of Bergman, took a more rational view of the "Science of Subterranean
Geometry," which Werner attributes to Agricola. In 1778 we find Pryce
adopting a reasonable theory as to the formation of fissures, and the filling of
them, by fluids finding their way through them. In 1791 Werner promul-
gates his "New Theory of Mineral Veins," which has been very generally
accepted; and this hypothesis modified by Bernhard Cotta may be regarded
as the prevailing view at present entertained. The views of Fournet and of
D'Aubuisson add to the ordinary views of Werner and Cotta as to succes-
sive openings of the fissures.* The latter, observes Necker, in 1833 intro-
duced some new views; mainly regarding mineral veins as being immediately
connected with unstratified rocks. The incompleteness of this view has
been already shown.
In 1833 Mr. R. W. Fox drew attention to the influence of electricity
in producing mineral veins. An endeavour has been made to show that
a certain amount of truth belongs to this view, but that it does not account
for many of the phenomena brought under notice. The views of Whitney
in America and of Wallace in the north of England are both deserving
of close attention. It, however, appears necessary, after this summary, to
examine more closely than has hitherto been done the conditions supposed
to have been active in the production of and the filling of veins.
There can be no getting away from the fact that metalliferous matter, in
* D'Aubuisson, “Traités de Géognosie," tome iii.
396
[BOOK II.
THE FORMATION OF DEPOSITS.
some form or other, must have been diffused through the rocks of the earliest
formations. Of the condition of this-the earliest lithological condition-we
know nothing, and it would therefore be idle to offer any speculations as to
the state of the primary Earth. Sufficient, that we suppose the metallic
constituents of the primary mass to have been broken up by convulsive
throes, or, by the action of silent forces, operating on all matter. The smallest
crystal of a metallic ore may form the nucleus about which a vast mass may,
in course of time, accumulate. Such a mass, or myriads of such masses, may
be strictly contemporaneous with the rock in which they may be discovered.
If the action of water is admitted—and it is not supposed that the influence
of a vast ocean can be denied-we have everything that is required to pro-
duce all the phenomena supposed to be due to segregation. Of this sufficient
evidence has been already given. Mechanical forces operating upon the
hardening rocks would naturally give rise to fissures. If the force acting as
undulations in a given line is admitted, then we have all that is required for
the production of fissured veins. By some force an immense number of
cracks have been produced in one general direction. In the process of time
another form of force, or a power acting in a different direction, gives rise to
a newer set of fissures. It may be that the first set of fissures formed have
been filled with metallic ores, or earthy minerals, before the second system
of rents was produced. We have, therefore, by studying those phenomena,
a means of determining the ages of the mineral veins so formed.
Supposing any of those veins to have been produced by the deposition of
metallic ores from the water in which they were held in solution.
It may
be that the mineral solution has been the result of lateral infiltration, or of
waters descending from the surface of the country dissolving out the soluble
salts contained in the rocks through which it has filtered, or it may be that
heated, or even cold, water has been forced from below, holding more
metallic matter in solution. In either case the very condition of being forced
through rocky cracks would be quite sufficient to cause some of the dissolved
matter to precipitate on the sides of the fissure-the walls of the lode-and of
course every change in the character of the solution would produce a change
in the nature of the precipitate.
Sublimation-in the form, we will suppose, of sulphur or arsenical vapour
-may bring up from the depths of the Earth matter which would be
deposited on cooling. We have evidence of this action on the bricks of
smelting furnaces, where very perfect crystals of pyrites are not unfrequently
formed.
It is quite evident from what has been said, that electricity may and does
act as a directing power, and that many of the conditions which are observed
are due to electro-chemical influence.
CHAPTER IV.
REMARKABLE PHENOMENA OBSERVED IN METALLIFEROUS ORE DEPOSITS.
ALREADY, in dealing with the History of Mining, while giving examples
of the methods adopted by the early miners in working out the mineral
deposits discovered by them, some of the phenomena observed have been
noticed. A few other interesting accounts of the mining operations, in
several parts of the kingdom, remain to be noticed, and beyond this, it
is desirable to direct further attention to the rarer phenomena of lodes, and
to some of the more striking peculiarities of mining.
In 1671 a paper was read before the Royal Society entitled "Observations
on the Mines of Cornwall and Devon." This informs us that up to that time
a system of open workings prevailed in these counties. The ore and rubbish
were raised by manual labour-being shovelled from cast to cast, or, as it
was termed, from shamble to shamble. Thus in case of a lode continuing
rich near the surface, a long chasm would gradually be formed. Chasms of
this kind are not so numerous as they were fifty years since, but still many
are to be found. These openings are called by the miners "Coffens." Mr.
Carne states that the open work at Sealhole mine in St. Agnes extended
nearly half a mile in length. At Polberro, in the same parish, a vast excava-
tion of this kind was made. Similar openings were, a few years since, at
Wheal Unity, Poldice in Gwennap, Wheal Vor in Breage, and at Godol-
phin. At Baldhu a Coffen, considerably over a mile in length, existed. At
Drake Walls, in the east of Cornwall, was a very extensive excavation of
a similar kind; it has, however, been nearly filled in, the miners being glad
of any such reservoir for their waste material. In St. Just, at Trevagean,
at Wheal Diamond, Bartinny Hill, Carnleskis, Wheal Dower, Fonthal
Moor, and Praze, similar openings on the backs of lodes formerly existed.
Mr. Carne gives the names of many others, as Coffen Crista, Coffen Carha-
rach, Coffen Garrow, and the like. At the Bunny there still remains a chasm
about 20 fathoms in length, and very nearly as wide. Similar evidences are
to be traced at Botallack.
The mineral wealth accumulated within any given area-the rocks of
which are known to be metalliferous-is limited so far as the superficial strata
are concerned. We learn that some mineral veins cease to be productive in
depth, while others continue to yield their treasures to the miner's industry
to the greatest depth to which man has yet penetrated. Beyond this limit
all is uncertainty, and probably the problem of the depth to which metalli-
ferous ores may continue is insoluble. The increasing density of the Earth as
we approach towards its centre certainly appears to indicate the presence of
398
[BOOK II.
THE FORMATION OF DEPOSITS.
very solid matter, which may possibly be of a metallic character. There are
phenomena also connected with subterranean temperature, and possibly with
terrestrial magnetism, which tend rather to support the hypothesis that a
solid mineral mass exists in the lower zones. The question of an igneous
centre is entirely beyond the point under consideration. With such specula-
tions therefore it is not the purpose of this volume to deal. The subjects
for especial consideration are—
First.-The depth to which minerals-the ores of the metals-may be
profitably followed.
Second. Is there evidence to support the hypothesis that thermal waters
rise from any very great depth?
Third. Are the contents of lodes or veins derived from the mineral
springs flowing from great depths-from vapours sublimated from the abyss
—or, are they deposits from waters percolating through the surface, or the
rocks holding mineral matter?
Having examined the conditions of our knowledge and established, as far
as facts will support our views, the known conditions regulating the dissemi-
nation of metallic and earthy minerals, we must proceed to inquire what
minerals have been removed from the natural deposits of all descriptions, in
the course of ages by human efforts, and what quantity of mineral wealth is
probably remaining within the area of the British Isles, to reward the labours
of man, aided by the ingenuity of his mind, and the engineering machines of
his invention, enlarged by the increase of scientific knowledge, and by the
powers of human reason. Attention must be invited, therefore, to the records
of the past, a careful examination must be made into the conditions of the
mining industries of the present, leading onward to careful deductions as to
the probabilities of the future.
An idea very generally prevails that peculiar surface conditions, especially
sterility, marks a productive mineral district. It has long been a common
proverb, "A poor surface gives a rich soil." This, however, is true only to a
certain limited extent.
In Cornwall, ranges of Granite hills covered with huge masses of "Moor-
stone" (Granite), heaped in fantastic forms, usually mark a mineral boundary.
Gently undulating plains spread away from the bases of those hills, barren of
vegetation, save the beautiful heath and the golden furze, which, when in full
flower, give all the appearance of a garden to an otherwise waste country.
These regions are commonly cut through by deep and often picturesque
valleys, and within the shelter they afford, numerous plants, and especially
shrubs, grow with a luxuriance not to be seen in any other part of Eng-
land. On the hills and spreading over the plains, or, more strictly speaking,
table-lands, are numerous tall chimneys, proclaiming to the stranger that
he is in a mining district. These chimneys belong to the magnificent
steam-engines which are employed in raising water from the deep mines,
many of them pumping from 1,800 feet, and in one case as deep as 2,500 feet,
and to the winding-engines by which the ores are raised, or to the crushing
or stamping machinery by which they are prepared for sale.
Wherever prosperous mines exist the country has a dreary aspect. Waste-
heaps-in many cases swollen into small mountains-are spread around, while
CHAP. IV.]
CHARACTER OF MINERAL DISTRICTS.
399
piles of mud, and pits of slime, gathered in irregular groups, indicate the
processes of separating the metalliferous from the earthy portions of the ores.
Consequently the whole character is, from either natural sources or artificial
causes, rendered one of barrenness and waste. Still many of the mines of
Cornwall are not without picturesque character and some beauty; while in
Devonshire we find copper and lead mines in the very midst of thickly-
wooded districts, spread along the margins of rivers which are of singular
beauty; while, again, the mines which exist on the borders of Dartmoor
partake of the general wildness of that moorland region, and the tin mines
of this elevated district are to be found in localities marked by desolation
reigning in savage grandeur, in solitudes the silence of which is only broken
by the brawling of the winter torrents, or the roaring of the equinoctial
tempests.
In Cardiganshire the mining district exhibits a roughly-featured, some-
times even corrugated, surface of hill and dale, which seldom rises into a bold
peak, or breaks into precipitous hollows. Mr. W. W. Smyth, in his memoir
"On the Mining District of Cardiganshire and Montgomeryshire," observes
"that the neighbourhood of the mines, when at a moderate elevation above
the sea, is rarely marked by that character of sterility generally observed in
regions which are favoured in their subterranean treasures. The wanderer
who pursues his winding way along the beautiful valley of the Rheidol, or
traces up some of the many other streams, which flow east and west from the
Plynlimmon range, is often struck with surprise to find himself, after a succes-
sion of purely rustic scenes, close to the mouth of a gallery, perhaps long ago
abandoned, which opens in the midst of a wood of oaks, or upon a fertile
meadow where the light tint of the conical burrow' or pile of excavated
rubbish offers a marked contrast to the verdure of the surrounding land-
scape." The copper mines in the Vale of Nantlle, not far from Carnarvon,
the mine of Cwmdyle, on the side of Snowdon, those mines which have been
worked in the immediate neighbourhood of Bedgellert, and the numerous
mines near Bettws-y-Coed, are in districts marked by features of peculiar
wildness and rugged grandeur. The lead mines of Flintshire are distributed,
some in spots distinguished by rural beauty, and others in an elevated
country of the most uncultivated character. The copper mines of the Coniston
district and the lead mines about Keswick are in the midst of scenes which
delight the heart of the true lover of nature. Then, again, the mining dis-
trict of Alston Moor, and of all that tract which extends across the country
from Alston to Shotley Bridge, consists of high, massive, rounded elevations.
"The hillsides in spring and autumn present a beautiful green surface, and
in summer an abundant and flowery produce in the meadows; while on the
same hill above the Limestone bare short grass, ling, and moss impart the
brown and dreary aspect which characterises all the higher portion of the
mining district" (Sopwith).
Descriptions of mining districts might be greatly, but not very profitably,
extended. The sketches given will sufficiently prove that mineral treasures
existing below the earth are rarely indicated by any peculiarities upon its
surface. Of all the districts named-and to these might be added the dales of
Durham and Yorkshire, with the picturesque valleys of Derbyshire—it may in
400
[BOOK II.
THE FORMATION OF DEPOSITS.
general terms be said, that they present scenes varying from the sublime of
precipitous rocks and rolling cataracts, to the calm and truly rural aspect of
Meadows studded with the herd and fold.
:
The luxuriance of a landscape does not indicate an absence of mineral
wealth, neither does a barren country give any evidence of the existence of
subterranean treasures.
The question, then, naturally arises, are there any natural indications to
be discovered on the surface by which the existence of metalliferous ores
beneath it may be inferred? Beyond the uncertain hypotheses-the result of
untrained experience—which bids us regard one peculiar character of rock as
being favourable—or, as the Cornish miner phrases it, “being keenly”—for ore,
and to avoid another as exhibiting unkindly features, there are no guiding
rules. There are apparently two constants which point to fixed laws, but these
have not been followed to their ultimate conclusions.
1. There are evidences that the direction, as it regards the Earth's
magnetic axis, has some connection with the metalliferous or non-metal-
liferous character of a lode. What form of force is in action to determine the
deposition of a metallic, or an earthy mineral, in special parts of a fissure,
remains a problem.
2. There are indications that, in many districts, the presence of two
dissimilar rocks are necessary to the production of a rich vein of ore. There
has been a disposition to regard these as a grand galvanic battery, but
experiments do not favour this view. Probably a more careful examination
of our mining districts may enable us eventually to quit the dangers of
reasoning by analogy, and by a system of clear induction to advance to some
general principles.
Beyond these we really possess but few, if any, guiding rules. The direc-
tion of the lode, and the necessity for the presence of two rocks having
chemical or physical differences, indicate some apparent connection with
electric or with magneto-electric phenomena.
As this subject is still under consideration, and will form the especial
subject of an important volume-which is in progress-by that most
competent authority, Mr. J. A. Phillips, it will occupy only so much space
in this volume as will be sufficient to teach those who are unacquainted with
the matter, of its importance and its interest. Connected with it are several
other matters, having collateral bearings on this great question, which must
come under our consideration.
During three thousand years, as tradition shows-by what may be
regarded, by some, as shadowy evidence—and for at least two thousand years,
-for which we have fairly reliable historical statements,-man has been
with great industry seeking for buried treasure. When we contemplate this
fact, we must become convinced that the exhaustion of the metalliferous
deposits which originally existed in the superficial rocks which we call
"the crust of the Earth" must have gone on to an enormous extent. It is
important to determine approximately, if we can, the value of the minerals
removed, and which can never be replaced, and thus to endeavour to arrive at
some satisfactory conclusion,-if it be possible,—as to the prospects of the
CHAP. IV.]
MINERAL LODES IN ST. JUST.
401
miners of future ages in their exploration of the profounder depths, or of the
unknown regions, of this planet.
It is not intended that a description of mines, generally, should be given
in this chapter. But a selection will be made of such as possess some natural
peculiarity, or are in any way remarkable, as mines, for the nature, or the
extent, of the excavations which have been carried out. The author will
attempt, as far as possible, to give examples which shall ensure a correct
knowledge of the phenomena presented to the observer, in each of the
various mining districts of the United Kingdom, and such as are peculiar
to special geological formations.
St. Just Mines.-There is much which is curious and instructive in
the mining district of St. Just. The accompanying copy from the map
of the Geological Sur-
X GRANITE
Cape
Cornwall
ALTERED SLATE '
GREENSTONE
LODES
FAULTS
a
Carndy
Botallack
Head
+
α
BotallackV
Mine.
Cove
Enys
Pendeen
Caswel
Bosorne
Botallack-l
17
Truthwall
ス
​Nanche rrow
-/
St Just
가
​Comyorch
T
Carn!
Kenidjack
ソノー
​т
Bosmedics
vey, Fig. 63 (which is
drawn to the scale of
one inch to the mile),
will materially assist
the reader: aa is a ridge
of Greenstone rocks,
which at Kenidjack
Castle and some other
places assumes much of
a basaltic character-
as do also some of the
rocks around Cape
Cornwall. The Slate is
marked on the map as
altered Devonian, but
the evidences of altera-
tion are not very satis-
factory, and this band
may be regarded as
Killas Clay-Slate-
somewhat indurated.
The rock within this, is
a small portion of the
great mass of Granite
which extends to Pen-
zance, St. Ives, and
Lelant. All the black lines are mineral lodes, which coincide with the
general direction of the joints in the rocks, being about south-east and north-
The greater number of lodes are indicated on the map; most of them
are short, and there are altogether between forty and fifty. The breadth
of this important mining field is small, and but few of the lodes have been
seen in more than one mine. The finer lines are cross courses, usually
called in this district guides. The small veins, whether metalliferous or not,
are designated by the St. Just miners, scorrans.
west.
+
Carn Greeb
Letcha.
人
​トーノーイ
​イ
​11 Bo
Bosworlas!
Fig. 63.-Map of St. Just.
The heaves are, as a rule, irregular. In many cases, although the lode
D D
402
[BOOK II.
THE FORMATION OF DEPOSITS.
has continued rich in actual contact with the cross vein, it has never been
discovered on the other side of it. This appears to indicate that the
flow of fluid matter by which the lode has been filled was stopped by the
cross vein.
The difference in the size of the lodes has a remarkable effect on
their productiveness. Where the lodes are productive, they are of fair
average width, and where the size diminishes, they are usually impoverished.
In every vein in the district the masses of metallic minerals have dipped
from the Granite, or if occurring in that rock, they have inclined towards the
Slate; in other words, the deeper portions of the ore have been farthest from
the Granite (Henwood). It will be seen that several of the veins run
under the bed of the Atlantic Ocean, and some of the mines are worked to
a considerable extent under the sea. In 1778 Pryce wrote: "At Wheal Cock
(a portion of Botallack) they have only a crust between them at most, and
though in one place they have barely four feet of stratum to preserve them from
the raging sea, yet they have rarely more than a dribble of salt water, which
they occasionally stop out with oakum or clay inserted in the crannies
through which it issues.”
The same author gives the following account of the workings in this mine.
"Wheal Cock," he says, "is wrought eighty fathoms in length under the sea
beyond low-water mark, and the sea in some places is but three fathoms
over the back of the workings; insomuch that the tinners underneath hear
the break, flux, ebb, and reflux of every wave which upon the beach
overhead may be said to have had the run of the Atlantic Ocean for many
hundred leagues, and consequently are amazingly powerful and boisterous."
Henwood, in 1831, writes: "At the cliff the level is 20 fathoms below
high water, but the ore was worked to within nine feet of the sea at the time
of my visit." This mine must evidently have been worked for a considerable
time before 1778, seeing that at that time the level from Wheal Cock was
worked 480 feet under the sea, and when the workings on this point were
stopped they had advanced about 780 feet from the cliff. From Wheal
Button shaft the length of the workings was still greater. They approached
1,950 feet when stopped at the depth of 115 fathoms, the deepest level,
which was not driven quite so far, being 180 fathoms below the adit. In
one part of Botallack the labourers have to descend to the adit by ladders
placed on the face of the cliff.
The late Mr. Henry Curwen Salmon,* in an excellent article on "Mining,
Quarrying, and Metallurgical Intelligence," written in 1862, thus describes
the position at that time of Botallack, and some operations then in progress.
As all this portion of the mine has been recently abandoned there is no pos-
sibility of obtaining equally correct information from any other source.
Those who have visited Botallack may remember standing on the cliff,
and looking down a distance of 250 feet upon an engine perched upon a
ledge of rock, employed in winding from a shaft some little distance below
that again. The shaft is called Pearce's whim shaft. To get to it you had
to descend a winding path cut in the cliff called the 'Mules' Path,' from
having been originally made for the use of mules to carry up the ore from
the shaft to the dressing-floors above. This whim shaft has been sunk to a
* 66 Mining and Smelting Magazine."

CHAP. IV.]
INCLINED SHAFT A1 BOTALLACK.
403
depth of 180 fathoms; but at every succeeding level longer and longer
drivings had to be extended from the shaft seaward, through unproductive
ground, in order to reach the orey part of the lode, which dips away from
the land. Thus at the 150-fathom level upwards of 200 fathoms of dead
ground had to be gone through, and at the 180-fathom level 260 fathoms of
dead ground. To pursue the shoot of ore further under such circumstances
became impossible. In a mine working under ordinary circumstances the
difficulty could have been met by sinking a new shaft down upon the orey
ground; but as it was not possible to sink a shaft in the Atlantic Ocean, this
resource was closed to Botallack. The lode was not to be readily aban-
doned, for it was a very rich one, having in one year between the 85 and
115 fathom levels yielded £24,000, and the ground above the 150-fathom
level having yielded £50,000. At last it was determined to sink a new
diagonal shaft from the surface, at such an angle that it should cut the
productive part of the lode in the bottom levels. This was accomplished,
the shaft being sunk 345 fathoms, cutting the 180-fathom level at a distance
of 260 fathoms from Pearce's shaft. As the Crown lode is enclosed in hard
Greenstone rock, it was found impracticable, except at enormous cost,
to make the shaft larger than 6 feet square. This is of course a very
small size for a shaft, and precludes the possibility of having more than a
single waggon way. The waggon used for working on this incline holds
about 16 cwt." The annexed woodcut, Fig. 64, gives a correct
section
SEA LEVEL
KILLAS
Wheal Cock
100
190
205
100
600
Bascovery
Diagonal Shari
Wheal Button
Shaft
GRANITE
Engine Shaft
Wheal Hazard Shad
The dark shaded parts show the ground that has been stoped away
200
1200
3.00
1800
400 Fathoms
2:00 Feet
Fig. 64.-The inclined Shaft at Botallack Mine.
of that portion of Botallack mine which is under the Atlantic Ocean, with
a representation of the diagonal shaft. It will be seen that the ore has been
found nearly always in the Killas (Clay-Slate). The scale being given, the
exact depth of the mine, and the extent of the workings, will be at once
understood.
On the 18th May, 1863, a sad accident occurred on this inclined shaft, by
which nine men perished.
This under-sea shaft, or rather plane, is sunk on the lode at a uniform
DD 2
404
[BOOK II.
THE FORMATION OF DEPOSITS.
dip of 32 degrees from the horizon, but with a varying direction, resulting
from its following the course of the lode. In consequence of the hardness of
the enclosing Greenstone rock this inclined plane is small, only allowing
room for a single line of rails, which are carefully laid on transverse and
longitudinal sleepers. The drawing is by waggons and chains, but the
men are brought up in a special carriage called a "gig" made of iron,
6 feet 10 inches long, 2 feet 5 inches wide, and I foot 8 inches high, provided
with four seats each arranged to hold two men, and also furnished with a
safety-catch, partly self-acting and partly controlled by the men in the gig.
The railway is completed to the 192-fathom level, but the shaft is sunk 17
fathoms deeper, and there is an opening of 2 feet 9 inches between the line of
rails and the sollar at the 192. The men who were killed were being drawn
from the 165-fathom level, and the gig had reached the 135-fathom level, when
the chain parted near the surface, and the gig fell away to the bottom of the
shaft. It does not seem to have left the rails as far as they continued, that
is to the 192, where, passing under the sollar, it plunged into the lower and
unfinished portion of the shaft. At the inquest, the verdict was
"accidental
death," the catastrophe being attributed to the carelessness, or want of
presence of mind, on the part of the men in the gig in not bringing the safety-
catch into operation. It is doubtful, however, whether under any circum-
stances men should be drawn up by chains, whatever precautions there may
be adopted in the shape of safety-catches or breaks. The uncertainty of
chains is proverbial; and in most other mines in Cornwall, where men are
raised by skips, a wire rope with a double-linked connecting chain is
adopted. The experience of every country in the matter of safety con-
trivances is, that while they usually answer perfectly on trial, they almost as
usually fail when a breakage really occurs.
There are many remarkable conditions to be observed in Botallack mine,
the occurrence of flat lodes being one of them. The whole tenement of
Botallack is said to be full of tin floors. Gryll's Bunny is a name given to
one of these, or rather to a number of small floors alternating with an
ochraceous ironstone, to the depth of 10 fathoms. These floors dip 3 feet.
in a fathom to the north, and have been worked about 40 fathoms on their
underlie, and as many on their line of bearing. The general produce is
150 lbs. of white tin in 100 sacks.*
* In this district we have that rare
combination of tin and copper known as Tin Pyrites, which Dr. Henry S.
Boase, M.D., discovered in 1822 in the mines of Botallack and Levant.
This mineral has been rarely found, except at Wheal Rock (now West Kitty),
St. Agnes, Wheal Scorrier in Gwennap, and Stenna-Gwyn, near St. Austell.
It is composed of—
Copper
Tin.
Iron
•
31
28
6
Sulphur.
Silica and alumina
Loss
25
7
3
The lodes of Botallack and Levant contain this variety of tin ore in the
vicinity of the cross courses; but when distant from them, the red ironstone
becomes less abundant, and the tin and copper ores are for the most part
* "On the Stratified Deposits of Tin Stone, called Tin Floors," &c. By John Hawkins, Esq., F.R.S.
(“Transactions of the Royal Geological Society of Cornwall, vol. ii. 1822.)
CHAP. IV.]
ST. IVES MINING DISTRICT.
405
disseminated in chloride, containing also no inconsiderable portion of
arsenical pyrites.
A lead mine in Perranzabula is another example of a mine which was
also formerly wrought under the sea. The miners were sometimes sensible
of a capillary stream of salt water, and, whenever they perceived it, they
stopped it by filling the cracks with clay, as at Botallack.
St. Ives Consolidated Mines.-No mine in Western Cornwall presents so
many remarkable features as this one does. The workings are, without doubt,
of great antiquity. There are not wanting evidences to prove that the whole
of the district from Halse Town to St. Ives was worked at a very early
period. The present mine was, however, commenced in 1818, and it appears
to have been started entirely for the purposes of a contested election. Before
the passing of the Reform Bill the borough of St. Ives returned two members
to Parliament. It will be readily understood that any industry giving
employment to a large body of men would possess considerable influence in
an election contest. This mine was commenced with but little hope of its
becoming a valuable one. Employment was to be given to a certain
number of men, who should become inhabitants of the borough, and be
entitled to vote for the members of Parliament. It was originally started
in 47 shares, which were successively increased to 94, 470, and 940.
The district which may be called the St. Ives and Lelant district demands a
more careful study than it has yet received. Within it we have the St. Ives.
Consols, Rosewall Hill and Ransom United, with Goole-Pellas, Providence
mines, Trelyon Consols, Wheal Margaret, Wheal Reeth, the group of mines
now known as Wheal Sisters, and several others, which have been more or
less productive, each one of them presenting some peculiarity either in the
lodes discovered or in the rocks by which these lodes are enclosed. St. Ives
Consols is a mine in Granite, although not far from the junction of that rock
with the hornblendic schists and Greenstones, which come in immediately to
the east, and indeed overlie the Granite in some of the eastern shafts. The
mine lies immediately to the west of the town, and the principal lode traverses
the bottom of the rather steep valley, through which passes the mountain
stream that falls into the sea at St. Ives. This is called the Standard lode,
and bears very nearly magnetic east and west-a little to the south of west-
and is in many places nearly vertical. The Standard lode has been worked
to the depth of nearly 200 fathoms. It is intersected by two principal cross
courses or trawns,—as they are called in this district,—made up principally
of decomposed Granitic matter.
The most remarkable feature, however, about St. Ives Consols was the
extraordinary deposits of tin which were found to the south of the Standard
lode, to which the name of The Carbona was given by the old miners. It is
impossible in a moderate compass to give a very accurate idea of this stan-
niferous formation; but it is more analogous to the "pipe veins" and
"flats" of the Limestone lead districts than to any other.*
The carbona branches off from the Standard lode. One carbona, called
Lawry's, shoots off at the 57 level, dipping rapidly as it goes south, and
forming stanniferous flats of various dimensions, which have been worked
* See description of "The Streek, Flat, or Dilated Vein,” p. 288.
406
[BOOK II.
THE FORMATION OF DEPOSITS.
into a series of irregular caverns, wholly unlike ordinary Cornish mine
workings. Another, or the Great Carbona-as it is called-goes off at the
77 level. At about 40 fathoms south of the Standard lode the level, which
is driven on the western cross course, intersects what is called Kemp's lode,
bearing nearly north and south, and which really seems to be a carbona
branch. This lode is driven on for some way until it meets Noal's lode, and
the flats and pipes coming down from Lawry's Carbona, at the junction of
which, the whole opens out into one of the most remarkable deposits of tin
ever found in Cornwall, the workings being excavated in enormous caverns
10 or 12 fathoms high and equally wide. All the dark spaces on the
annexed woodcut (Fig. 65) represent the various cavities which have been
worked out in different parts of the flat lode. The white lines are levels
driven at the several depths named, in fathoms of 6 feet each. This will,
therefore, give a correct idea of the extent of these vast excavations.
35fm
57
17
107
Fig. 65.-The Great "Carbona," St. Ives, Cornwall.
The term carbona is confined almost entirely to the St. Ives district, and
several strange suggestions have been made, as to the source from which
the name has been derived.* This can, however, be no longer doubtful. We
find in the New Testament-published at the English College at Rheims,
A.D. 1582,-in St. Matthew, chap. xxvii. v. 6, the following:-
"Principes, autem sacerdotum, acceptis argenteis dixerunt: Non licet eos
mittere in carbonam :”
This in English becomes-
“But the chief priests having taken the pieces of silver, said: It is not
lawful to put them into the carbona, because it is the price of blood."†
* The doubt which surrounded this term may be judged by the following note by the late Mr. H. C.
Salmon, who was intimately acquainted with Cornwall: "There has been some discussion respect-
ing the etymology of this word, which antiquaries of the old Celtic school have pretended to identify
with an ancient Cornish word. There seems, however, no ground for this, and the word is probably
an unaccountable corruption of some slang mining phrase." ("On the St. Ives and Lelant Tin-mining
District.")
+ The carbona was a place in the Temple where the people put in their gifts or offerings. It was, in
fact, the treasury. Upon submitting the question as to the correctness of this definition to the Rev. Allen
CHAP. IV.]
THE ORIGIN OF THE TERM "CARBONA."
407
It is a curious and not uninteresting fact to find the miners in Derbyshire
applying the terms vestry and treasury to rich deposits of lead ore occurring
in "flats" in the Limestone. The continuance of the term carbona from the
time of the Phoenicians appears to be confirmatory of the traditions relating
to their trading with Cornwall for tin.
In the Providence mines, near St. Ives, they have discovered similar flat
lodes, to which the same term carbona has been given. The whole of these
workings on the Great Carbona of St. Ives Consols were some years ago
ruined by a fire which consumed the stull, or timberings (made of the largest
timber procurable) that supported the workings, and which continued burn-
ing for six weeks, leaving the whole mass in irretrievable ruin. It must be
understood that all these great carbona deposits were made about the western
cross course, which afforded a convenient easement for the driving of the cross
cuts, by which the tin stuff was brought back to the working shafts on the
Standard lode. It is noticeable that all these carbonas form to the south of the
Standard lode, and that when they near that lode they are generally small :
indeed, looking at the matter in a large view, they seem to have been
developed on an extensive scale by the contact of a series of approximately
east and west lodes or branches, which range about 80 fathoms south of the
Standard-lode with the converging cross courses.
The beginning of a carbona was seen in a level driving south-east at the
67, about 12 fathoms from the Standard lode. In the end there is a pipe,
reaching about half-way up, surrounded entirely by Granite, and made up
principally of Schorl, with some tin. The carbonas, when productive, are
essentially characterised by a great development of Schorl.
The principal workings in the mine are about the eastern cross-course;
their most striking feature is the immense width of the workings, often
spreading upwards of 40 feet, although, when unproductive, the lode is
scarcely traceable.
The surface of St. Ives Consols is divided into a remarkable number
of small inclosures, belonging to different people. There are upwards of
twenty lords of the freehold of this mine sett; and that a mine can be
worked at all under such circumstances shows the excellent system of
mutual conciliation which is so characteristic of Cornish landlords in the
granting of mining setts. This mine commenced dividing profits in 1827,
and between that period and 1862, £107,418 were paid in dividends to the
shareholders. The early accounts of St. Ives Consols are lost, but we
find that from 1835 to 1862 the quantity of black tin sold amounted in value
to £478,030 15s.
The Flat Lode of Carn Brea Hill.-Extending from Wheal Uny to South
Condurrow and Wheal Granville there exists a remarkable deposit of tin,
Vawdrey, vicar of Sithney, the following reply was received from that gentleman: "The term 'carbona'
seems to be a well-known one by miners in this parish also, and is used by them to denote a piece of
ground unusually rich in mineral. What sort of a load is a', Bill?' 'Haw, a beauty-a regular carbona.'
I cannot help thinking that you have hit upon the right derivation. The Greek verse to which you refer
runs thus: Οἱ δὲ ἀρχιερεῖς λαβόντες τὰ ἀργύρια εἶπον οὐκ ἔξεστι βαδεῖν αὐτὰ εἰς τὸν κορβανᾶν. The
miners ought to call it corbana,' not' carbona.' The word is not Greek, but Syro-Chaldaic, or, more
correctly, Aramaic, the language spoken by the Jews in the time of our Lord; and it certainly means a
place very rich in good things, for it signifies the spot in the Temple where all the кopßavs, or rich gifts
and offerings, were placed. May not the use of this term in the county be a part of the proof that there
were Jews in Cornwall?
408
[BOOK II.
THE FORMATION OF DEPOSITS.
which is generally known as the Great Flat lode. This unusual formation
has been studied by Dr. C. Le Neve Foster, who thus summarises his
observations.*
“Their distinctive features are: (1.) The invariable presence of a small
leader, generally only a few inches wide, apparently occupying the space
due to the shifting of the two sides of a comparatively flattish fissure, and
filled partly mechanically and partly chemically. (2.) A lode (or mass of
stanniferous schorl rock), containing from 1 to 3 per cent. of Cassiterite from
4 to 15 feet in width, either above, below, or on both sides of the leader.
The tin is distributed in little grains in the rock, or in strings, or minute
veins. (3.) Schorl rock, poor in tin ore (locally called capel, greyback, black
granite, mother of tin), separating the lode from the Granite and schorl rock,
with its constituent minerals arranged in layers, also called capel, separating
the lode from the Killas. (4.) Gradual passage of the schorl rock with lode
on one side, and with Granite or Killas on the other; in other words,
absence of any wall between the capel and the lode, or between the capel
and the enclosing rocks."
Dr. Foster regards as new the fact of the lodes themselves consisting of
schorl rock, "a point which has never before been made known." He then
puts forward the idea that "the lode and capel are merely altered rocks, the
fissure now occupied by the leader having served to bring up vapours or
solutions capable of entirely changing the rocks on both sides of it." He in
another paragraph says: "It must not be supposed the schorl rock is the only
form of altered Granite. The conversion of Granite into greison' is not
uncommon, and Professor von Cotta † has given ample proof that the fine-
grained, dark-coloured Zwittergestein has also been derived from the same
source."
<
It has been previously remarked that the so-called metamorphism of rocks
has been pushed to a severe extremity, and that the evidences of the altera-
tion in the physical structure of Killas and Granite at their points of junction
are frequently entirely wanting. Dr. Foster says: "Killas is often seen altered
into a schorl rock, but here the two minerals are disposed in layers; sometimes
it is schistose (tourmaline schist), at other times compact (capel)." The italics
are marked to indicate that the layers would appear to show that the altera-
tion has consisted not in a change of the Killas into schorl, but of a deposit
of tourmaline in layers upon a deposit of Clay-Slate.
It is necessary here to describe briefly the Flat lode as it is seen in the
workings of the different mines (Fig. 66). In the more eastern part of Wheal
Uny the strike is 22° north of west, but to the west it goes south, and strikes
west 37° south, and sometimes south-west. It dips about 46° south. At
South Carn Brea the same lode has been followed between the Granite and
the Killas for 175 fathoms. The course of the lode is generally about
east 33° north, the dip about 35°. This mine was worked for both tin and
copper.
West Wheal Basset was originally started to work a copper lode dipping
* "On the Great Flat Lode, south of Redruth and Camborne." By C. Le Neve Foster, F.G.S., &c.
("Quarterly Journal of the Geological Society," for August, 1878.)
+ "Frestschrift zum hundertjährigen Jubilâum der Longil sächs." Bergakademie zu Frieburg.
Dresden: 1866.
CHAP. IV.]
THE GREAT FLAT LODE, CARN BREA.
409
north, and eventually the Great Flat lode was intersected. The lode is now
entirely in Granite. South Wheal Frances has the flat lode dipping from West
Basset. It was intersected first at the 185-fathom level, and is known to
exist also at the 205-fathom. The average dip is 32°, and the course about
east 41° north. This lode is faulted by three or more lodes underlying north.
S.CONDURROW. WHEAL GRANVILLE WEST WHEAL BASSET
A
80
FLAT
100
SOUTH FRANCES
XXX
E
150
ODE
FLAT
LODE
220
WHEAL ONY
FLAT
LODE
Fig. 66.-Sections of the Great Flat Lode on Carn Brea.
150
At South Condurrow and in Wheal Granville the Great Flat lode is en-
tirely in Granite. The average bearing is about east 34° north, the dip 30°
south.
The same authority has some remarks on the probable changes which
have given rise to the flat lode. The following are of interest :-
"That Granite can be altered into schorl rock is a fact that can scarcely
be questioned. Every china-clay pit affords us evidence of the fact. You
constantly find little veins of quartz, or quartz and tin ore, bounded on each
side by granular schorl rock, which is followed by Granite more or less
decomposed. I have specimens in my possession of a passage-rock showing
pseudomorphs of Gilbertite, after orthoclase, enclosed in schorl and quartz.
The sharp walls of the quartz veins on the sides of the original fissures, and
the absence of such walls between the Granite and the schorl rock, is what
would be expected if the altering solutions gradually soaked in from the
sides. Sometimes the schorl rock itself bears plain marks of its origin, as it
contains numerous pseudomorphs of quartz after orthoclase. This is nowhere
better seen, than in some rocks, occurring in the Granite near Penstruthal
mine south of Redruth. The pseudomorphs are more than an inch long by
inch wide, and are imbedded in a mass of schorl with a little quartz.
The changes referred to in the Granite are seen in a striking manner
at Wheal Coates, in St. Agnes, at Cligger Head, and in some of the china-
clay works near Roche Rock, St. Austell. They are also well illustrated in
the fine clay pits at Lee Moor, on Dartmoor. But the evidences in all
these cases rather point to chemical changes produced by natural ordinary
causes than to any alterations due to subterranean influences of a thermic
character.
Dr. Foster supports his position by referring to the very remarkable
deposits at Balmynheer, in Wendron, at Wheal Lovell, near Helston, and
some other tin mines. His description of the South Wendron district.
deserves a careful study:
*"On some Tin Lodes in the St. Agnes District." By C. Le Neve Foster. ("Transactions
"On_some_Tin
of the Royal Geological Society of Cornwall,” vol. ix. part iii. 1877.)
410
[BOOK II.
THE FORMATION OF DEPOSITS.
"East Wheal Lovell, on the south-east, is worked upon a pipe of tin-
bearing rock of a somewhat remarkable character (Fig. 67). The easiest
way of giving an idea of it is to describe it as a very irregular cylindroid of
stanniferous rock, A B, merging gradually on all sides into Granite, with its
axis dipping at an angle of 49° from the horizon in a direction north 25° west
(true). The longer axis of the oval section of the pipe varies from 20 to 60
feet in length, whilst the shorter is about 10 feet. The mass consists of
quartz, mica, Gilbertite, a little iron pyrites, and tinstone, and is traversed
by a few irregular joints. The southern part of the pipe is sometimes very
XX
x
+
A
+
+
N(true)
x + x x x x
XX
+
x
x
f
x x
XX
XXX
X
f
+
х
メ
​+
1.
+ + + +
+++++
+ +
+
+
ㅏ
​ރ
メー
​хх
メ
​+
x
+
ххх
S.S.W
Nirue
Broys MONT
"We East Whim Shar
NNE'
17:
20
Old. Workings
Junction with South Lode
26
90
area
45
60
36
20
la Pipes & Bunches of Tin Ore
One M
B
Granite
Rock impregnated
with Tin Ore
Fig. 67.-Plan of Deposit at
East Wheal Lovell.
100m
Scale 1:2880
1050
10
20
30 Fathoms
Fig. 68.-Section on the North Lode at East Wheal Lovell.
Granitic in appearance, and consists of pink orthoclase crystals imbedded in
a mass of quartz, chlorite, mica, iron pyrites, a little copper pyrites, fluor, and
tin ore.
A glance at the section (Fig. 68) shows considerable irregularities
in the shape of the several pipes and bunches, as might be expected from the
shifting of an irregular fissure. The only difference between this and the
carbonas of St. Ives is the absence of tourmaline.
The Valley of the Loe Pool.-Although the stream-tin or alluvial ore may
have been first discovered, yet it is not probable that any long interval elapsed
before the veins became also known as sources of this mineral, especially as
it is often found that rich lodes crop up in the stream ground, the hard
matrix having resisted the agencies that had degraded the rock containing
it. This is particularly observable in the stream ground about Porkellis, in
Wendron, where streaming and lode mining have been simultaneously
carried on. Some of these outcrops have been subsequently explored to
considerable depths at Wheal Foster, Porkellis United, Basset and Grylls,
CHAP. IV.]
STANNIFEROUS DEPOSITS OF LOE POOL.
.411
and Wendron Consols mines, whence large quantities of tin have been
extracted.
The valley of the Cober rivulet, in which these mines are situated, has
been perhaps the most productive of alluvial tin ore of any in Cornwall; and
it is somewhat remarkable that, while the stream works at Carnon, Pentuan,
and the St. Erth valleys have been particularly described, this has remained
comparatively unnoticed.
From its source among the Granite hills at Viscar, in Wendron parish,
to its influx into the Loe Pool, the rivulet has a course of about five and a
half miles. Near its source the alluvium is shallow and comparatively poor,
though it has, apparently, all been turned over at some remote period. The
underlying rock is coarse-grained, semi-decomposed Granite, traversed by
hard dark blue veins, or "capel," containing patches of tin ore. In the
neighbourhood of these veins the rock is often stained with oxide of iron.
In places where some of these veins have been worked, it has been
found that this coarse-grained rock extends to a depth of about twenty
fathoms, when it becomes hard and glassy. The tin-bearing veins also
become small, and the mining prospects altogether being such as have not
been held to warrant very extended exploration. The tin ore is sparsely
diffused in the soil and gravel on the hillsides, which also show traces of
having been turned over extensively. Descending towards the village of
Porkellis, the valley widens into an irregular basin, the bottom of which
has been very productive of stream tin. The bed rock occurs at depths
varying from six or seven to above twenty fathoms. In some places false
shelf is met with, which on being broken through is found to cover a more
ancient alluvium, which is generally rich in tin ore. Numerous veins tra-
verse the “country," all of them more or less productive. On one set, still
called “Balwath," or the "old mine," tradition reports that the first steam-
engine in Cornwall was erected, the steam being raised by turf fuel. A
little below this, near the village of Porkellis, the rivulet is joined by an
affluent from the north, and about this place the valley widens considerably,
and it was probably here that it has been most productive of tin. The whole
bed has been repeatedly turned over, and operations on some parts are still
continued. With great labour, a deep cutting has been brought up on one
side, from about a mile down the valley, by which means a number of little
wheels have been put in motion to drain the workings. The moor presents
a most desolate aspect, being absolutely treeless, and studded with irregular
banks of gravel, scarcely covered by a scanty herbage, between which are
deep black pools, the relics of abandoned works. About a mile below Por-
kellis, at Trenear Bridge (where the substructure of a building said to have
been a hunting-seat of the old Earls of Cornwall is still seen), the Granite
hills on the eastern side close in upon the valley, which for another mile is
much contracted. The whole of the alluvium has, however, been streamed
probably more than once, but during late years the banks have been carefully
levelled and covered with a thin stratum of soil, so as to convert the land
into meadows. At Tregrannack the Killas or Clay-Slate formation is entered
upon, the surface junction of the tin rocks crossing the valley obliquely. The
valley here spreads out into a large basin, which at some remote time has
412
[BOOK II.
THE FORMATION OF DEPOSITS.
been very carefully streamed. The alluvium is here mixed up with large
boulders of Granite and Greenstone, patches of which occur here in the
Clay-Slate, and it is noticeable that the gravel underneath these boulders,
where they were too large to be turned over, has been scraped out by
using some long-handled instrument. The slopes of the hillsides, formed
by the detritus of the Clay-Slate, have been perforated by small adits at
the base, in order to extract the subjacent gravel, so that it is difficult to
find the smallest portion of alluvial soil left in its original position. Many
of the Greenstone and Porphyritic boulders have one or more hemispherical
cavities on their surfaces, as if the tinstone was pulverised by hand in these
rude mortars. Other fragments of probably a much later date (generally of
Granite, which would admit of being more easily shaped for the purpose)
evidently formed portions of rude grinding-mills of the fashion of the Chilian
"arastras." They were driven by water, and the rubbing surfaces are deeply
grooved in concentric rings by the hard material they were used to treat.
Just above the surface junction of the Granite and Clay-Slate rocks the valley
is crossed by a hard bar of rock, which is now extensively quarried. In
opening the quarries a few feet above the level of the river a number of
circular cavities were found, ranging from about 5 inches to 18 inches in
diameter, and from 4 to 6 or 7 feet deep; the contents consisted of pebbles
of almost pure Cassiterite. At the time of their discovery the peculiar
formation of these deposits caused much discussion among the miners, more
especially as the horizontal fissures, leading into them, were so narrow that
they could not be seen till the rock above had been quarried and removed;
from which circumstance it was erroneously supposed that the pits were
quite imbedded in the solid rock. The real origin of these formations was
no doubt due to the eddying of the water about the margin of the stream,
which, carrying the hard tinstone round and round, in course of time disin-
tegrated the rock and hollowed it into these peculiar circular forms. To have
effected this a very long period must have been necessary, and the quantity
of water flowing through the valley must have been much greater than, from
its present surroundings, can now appear possible. It may be noticed that,
in the Slate cliffs about Newquay, cavities of a similar shape may be seen in
course of formation between high and low water mark, one or two fragments
of hard stone being seen at the bottom of the hollows. Evidently by their
grinding action, when moved about by the eddying water, those wore the
softer rock, and gradually deepened the pits in which they lie, and from
which it is scarcely possible they can be thrown out by any turmoil of the
waves.
It is noticeable in the Cober Valley, above the junction of the rivulet with
the Loe Pool, that nearly all the affluents to the main stream come in from
the north-west, a circumstance that is perhaps due to a peculiarity in the
cleavage planes, or bed-ways of the rock, giving the springs a tendency to
issue in a particular direction. On the sides of the valley opposite to these
affluents (which are now insignificant) the slopes become very steep, in
places almost precipitous, suggesting the idea, that at the time of their
formation the springs were much more copious than they now are.
At one
place, nearly opposite the opening of the branch valley from Trevarno, a
CHAP. IV.]
THE MINING DISTRICT OF HELSTON.
413
shelf projects horizontally from the opposite side of the valley, the surface
of which is covered with a thick stream bed, from which the tin has long
since been extracted, leaving the heaps of water-worn pebbles, which are
of precisely similar character to those covering the bed rock in the present
bottom, 30 feet below.
To a greater or lesser extent the whole of the alluvium, down to the
Helston town mills, has been wrought by streamers for tin ore, but from
this point to the Loe Pool the "overburden" is so deep as to present con-
siderable difficulties in the way of reaching the bearing ground, though
local tradition affirms that it is very rich. One vigorous effort was made
about the year 1840, when a large square pit was sunk, the sides being
strongly boarded. Much of the overlying matter passed through, in this
work, was found to consist of leaves and twigs of hazel and alder, compacted
together, and so preserved by the bog-water, that the natural colours of the
leaves were apparent as the masses were first turned up by the spades of the
workmen. A few days' exposure to the air, however, completely decomposed
the mass into a black viscid mud, which pressed so heavily upon the
timbered sides of the pit as to crush it hopelessly together. The distorted
sides of the excavation, and the reeking mass of black slimy mud, presented
so melancholy an appearance, that the name Wheal Caudle was instinctively
applied to it. The intention was to have driven levels in all directions from
the bottom of the open excavation, but it was found impossible to effect this,
and although it was understood the produce was not unsatisfactory, the
undertaking was abandoned.
While in progress, strict watch was kept for any organic relics in the
stream ground, but beyond large trunks of oak and elm trees mixed up
with the vegetable matter nothing particularly noteworthy was found. The
leaves lay nearly all horizontally, as if they had been brought down by the
stream into a still pool, and had there quietly sunk to the bottom.
It may be remarked that, while the Granite formation about the upper
part of the valley is traversed by tin-bearing lodes, just below the surface
line of junction with the Clay-Slate, where bands of Greenstone crop out,
there occur several copper veins, one of which at Wheal Trannack was
very successfully wrought on for some years, the workings attaining a depth
of above one hundred fathoms. Below the Trevarno Valley the rocks are
traversed by lead lodes. One of these, at the very margin of the Loe Pool,
was worked extensively about the latter part of the last century-—it is
reported, to a depth of sixty fathoms-and a large quantity of rich silver-lead
ore obtained. This was melted on the spot, where numerous portions of the
lode are still thickly strewn about. To prevent the flooding of the workings
of this mine by the overflowing of the lake, an adit was tunnelled through
the solid rock at the north-west extremity of the bar, or bank of shingle, that
separates the Loe Pool from the sea. Owing to the violence of the waves
throwing up sand, and choking the outlet, this enterprise did not altogether
answer the purpose, and the difficulties connected with the drainage brought
about a failure of the mining undertaking.
The Wheal Vor Mine.—A feature likely to arrest the notice of strangers
in the mining districts of Cornwall is the numerous small enclosures into
414
[BOOK II.
THE FORMATION OF DEPOSITS.
t
which the land is divided. A plausible reason for this is given by the fact
that when mining was not profitable the miners turned to farming; and as
the commons were, by spade industry, brought into cultivation, the fields or
"quillets" of land were hedged round in dimensions suitable to the small
scale in which they carried on their work. There was a fashion prevalent
among miners, by which they bequeathed their experience to those that came
after them, by planting in the banks adjacent to the places where they had
obtained favourable results a sprig of the elder or "scaw"
scaw" tree, while, the
oftener recurring places, where their labours had been fruitless, were marked
by the significant emblem of a black thorn. It is an old proverb among
miners that a "good lode is good from grass," and experience of the best
mines shows that large deposits of mineral generally crop out shallow on
the course of the vein. It is just such a history as this that appears to
belong to the famous Wheal Vor mine, or, as it should perhaps be more pro-
perly spelt, in its old Cornish form, Huel Veor, signifying "the Great Work-
ing." The vein upon which the chief workings occur bears a few degrees
north of east, being just at right angles to the Granite ridge of Tregoning
Hill. On the north-west summit of its two-peaked top are the relics of the
ancient earthworks from which this hill derives its name, Tre-Konning,
or the "King's Place." The outcrop of the mineral appears to have been
against the "great flookan," which formed the natural western boundary of
the late sett, and on the soft back of which the valley was worn out by the
spring which, previous to the adits being driven in, was supplied from
the porous portions of the vein. Probably this outcrop was turned over
to as great a depth as could be reached by the early miners; but the first
record of the working of the ground as a mine, relates to its being a portion
of the extensive works carried on by the Godolphin family, in the fifteenth
and two following centuries. The ore course was then apparently followed
down as far as the means of drainage enabled the miners to go; and it
is reported that one of the earliest steam-engines was erected here to pump
out the water. This was probably towards the close of the seventeenth cen-
tury. From about 1705 to 1715 it is said that one of Newcomen's engines
worked on the shaft, in front of the account-house still standing, by which
means that shaft was sunk 60 fathoms under adit. Here the ore course
appears to have become small, and operations were abandoned shortly
after the latter date. The mine was certainly left in abeyance till the
year 1812, when Captain John Gundry,—a member of an enterprising family
of miners, resident at Goldsithney,-recommenced operations by employing
a Mr. Bratt to put up a steam-engine on the old shaft.
The report of the former productiveness of the mines appears to have
been kept up, and on this becoming known, a rumour went through the
district "that there would be a plenty of tin to be had, as Wheal Vor
was going to be worked again." The surface at this time was described
as presenting the appearance of two deep parallel trenches, covered with
brambles, evidently the remains of the early open workings.
ceeding to drain the works, a "sollar" or platform was found in the shaft
near the adit level which had six holes. through it, corresponding to six
rods that were reported to have been hung from the beam of the old
On pro-
+
CHAP. IV.]
THE GREAT WHEAL VOR TIN MINE.
415
Newcomen engine (one to each drawing lift of ten fathoms). The holes pro-
bably served as guides to the rods. The bottom of the mine was found to
be 60 fathoms below the adit (which is 30 fathoms from surface at this
place), and the lode at the deepest point was small and poor. In the course
of a few fathoms' sinking, however, a branch of tin ore was discovered in
the shaft, which gradually increased in size till the mine became profitable.
Unfortunately this was not in time to save the enterprising projectors
from bankruptcy, and the mine passed into other hands.
The Wheal Vor lode underlies north about two feet in a fathom, and the
shoot of ore from its outcrop in the western part of the sett dips last as it
deepens at about an angle of 45°. When a depth of 115 fathoms had been
reached, a cross course, subsequently known as Woolf's cross course, was
encountered. Here the lode appeared to be completely cut out, and every
effort to discover it on the other side for a long time failed of success. One
of the miners, called Beaglehole, persisted in the opinion that the "heave'
had been to the left or north side, and he was allowed to have a pair of
men to drive in the direction he had indicated. In a comparatively short
time he succeeded in finding one of the richest and most continuous courses
of ore ever found in any country. The general dip of this ore ground con-
tinued as before, an average angle of 45°. It was not always of the same
richness, but at times, when the value diminished, the richer portion would
again be found, on driving farther east, the whole roughly resembling a
succession of large irregular steps. About 150 fathoms to the east of
Woolf's cross course a second cross course, to which the name "Bounder'
was given, was met with, and here again the ore deposit greatly increased
in size and richness, and so continued to within a short distance of the
present bottom of the mine at 310 fathoms below adit, showing every sign
of maintaining its productiveness as it approaches a third cross course
known to exist about 100 fathoms still farther to the east.
It was noticed that where the lode was most productive, the cleavage
joints dipped into it nearly vertically on the north, or hanging wall. These
joints were filled with veins or strings of tin ore, accompanied with white
lithomarge or "prian." These strings were so numerous and rich, that the
rock containing them was often excavated to a width of above 50 feet, and
in some instances to more than double that extent.
To treat the immense mass of ore stuff raised from these great excava-
tions, it became necessary to extend the operations of preparing the ore for
market to a vastly greater scale than had previously been required in
Cornwall. At first the water power available in the vicinity of the mines
was employed to work stamping-mills, for pulverising the mineral, and as
much of this was exceedingly hard, kilns were put up, in which it was
calcined before being subjected to the stamps, in order to facilitate its
reduction, an expedient that perhaps might at this time be adopted in
other tin mines with advantage. Eventually steam was, for the first time,
applied to provide stamping power, thus saving the heavy cost and loss
attending the carriage to the water stamps; to this was added furnaces and
appliances for smelting the ores, which, amounting at one time to nearly
one-third of the total produce of Cornwall, there was some difficulty in
416
[BOOK II.
THE FORMATION OF DEPOSITS.
disposing of at a satisfactory price, in the form of ore or black tin.
Indeed, the adoption of this course seems to have been a necessity, for early
in the year 1826 we find the purser applying to a business friend in London
for advice on the subject, to which the reply was clear and decisive, "The
adventurers must go on smelting or stop the mine." The price for metal at
this time was £88 per ton. To the original Wheal Vor mine the adjacent
setts of Polladras Downs, Penhale, and Carleen were subsequently added,
and the gross produce of the amalgamated mines, at one time, reached 220
tons of black tin in a single month. Seeing the great apparent influence
of the cross courses in enhancing the productiveness of the lode in Wheal
Vor, an idea prevailed among the mine agents, that as the shoot of tin in
Carleen mine—at the extreme west against the Granite, as it dipped east-
came in contact with the great cross course, forming the boundary between
that sett and Wheal Vor, similarly good results would be found near this
junction. It was hoped that this would be the top of a second course of tin
ore which would underlie all the workings that were then so productive,
and it was their hope that at some time the extension in depth of the
old western shafts in Wheal Vor would enable them to prosecute their
explorations in this direction.
This hope, however, was not realised, for in consequence of circumstances
arising from the bankruptcy of the Messrs. Gundry—the original projectors
of the mine-legal proceedings were entered upon by their representatives to
recover possession of the property. The litigation in the Court of Chancery
lasted for about twenty years, hampering the operations and ultimately
bringing this magnificent enterprise to an untimely end in about 1848. The
surface refuse of the mine continued, however, to be worked over till about
the year 1852, when a new company was formed to reopen and extend the
operations of the old mine. In the Mining Record Office, plans and sections
of the Great Wheal Vor, completed up to the closing of it in 1848, were
preserved, showing that the bottoms of the mine were exceedingly poor when
they were abandoned. Had these drawings been carefully examined, and
the indications, shown by the constant lessening of the "stopes," been
attended to, it is not probable that any set of mine adventurers would have
been persuaded to incur the enormous cost of pumping out the water from the
vast extent of subterranean workings. This was effected by the erection of
a magnificent pumping-engine, having a cylinder of one hundred inches
diameter, which was considered by all, as one of the finest works of Mr.
Michael Loam, the well-known Cornish engineer. The history of this
undertaking would show one continued series of unfortunate blunders and
mistakes, so that the water was scarcely got out of the workings before the
company was involved in difficulties. The mine was again allowed to be
filled with water, and the remaining resources of the company were applied
to the development of a parallel lode to the south. The result was very
successful, a profit being realised of about £100,000. A total depth was
reached of 220 fathoms from surface, and the works were continued till their
abandonment during the depression of 1877.
In the moors of Towednack, Wendron, St. Austell, Luxullion, Alternun,
and a few other places, the tin ground lies far within the boundary of its
CHAP. IV.]
DIFFUSION OF TIN IN CARCLAZE MINE.
417
native rocks, the earthy ingredients of the rock so closely resembling the
general character of the minerals as to prevent absolute identification of the
rocks and veins. The detritus which has been reft from these, and which
forms the tin ground, occurs near the junctions of the different systems, as in
the swamps of St. Austell, Luxullion, and St. Columb Major. The débris of
the geological stratum immediately beneath generally prevails, sometimes,
indeed, to almost an entire exclusion of the associated ore. Generally
speaking, however, the fragments are intimately mixed, but frequently not in
the same proportions throughout. This, however, is not always the case, for
at Carnon stream the upper and the lower parts vary in their mineral
character, the lowest being the richest in tin.
Carclaze tin mine has been one of the best examples of this class of
formation, as well as of a mine "worked open to day." The excavation at
Carclaze, when Mr. Thomas wrote a description of it half a century since,
occupied five statute acres, its depth was 136 feet, the solid contents 63,000
cubic fathoms, and tin to the value of a million sterling had been removed.
M. Jars * thus describes the works as observed by him more than a century
since: "About two miles from the town of St. Austell is a mountain slightly
elevated, but very extended, which forms a filon en masse, which we call in
Germany a stockwerk. It is a rock of the nature of Granite, of a white colour,
and very friable, which contains an infinite number of small veins of tin.
These veins are almost always parallel, and their direction is east and west.
The part of the rock which is not worked is of the same nature as the worked
portion, but very much harder. It is broken out, however, with a pick and
wedges of iron.”
MM. Von Ocynhausen and Von Decken+ give the following account of
this remarkable open-work:-
ore.
"The mine forms a large excavation open to day, and is said to be 250
fathoms in length and 100 fathoms in breadth, and 21 or 22 fathoms in depth.
The direction of the greatest length of this remarkable opening is 30° north
of west. In the eastern part of the excavation are several shafts sunk below
the bottom of it, by which tin ore is raised to a depth of 10 fathoms under
the adit. The Granite of Carclaze is intersected by numerous veins and
strings of tin ore, and adjoining those veins the Granite also contains tin
These veins consist chiefly of quartz and schorl. . . . . These tin lodes.
run in every direction through the Granite, but they are more prevalent in
one direction than in any other, that is a direction 22° north-west; their
underlie is towards south; the angle they form with the horizon is 35°. The
distance between these veins is very short, so that they give to the rock a
stratified appearance. Other tin lodes run between 15° and 30° east of
north. They intersect the former tin lodes without heaving them, and also
without being heaved by them. It is said that very rich tin ores are found
where these different lodes intersect each other."
Prof. Sedgwick‡ thus describes this interesting geological phenomenon :-
*M. Jars, "Voyages Métallurgiques; ou, Recherches et Observations sur les Mines et Forges de Fer,
&c., faites depuis l'année 1757, jusques et compris 1769, en Allemagne, Suède, Norwège, Angleterre,
Écosse, &c." 3 vols. 4to. Lyon: 1774.
+ " Philosophical Magazine and Annals" in 1829.
"Cambridge Philosophical Transactions," vol. i. p. 108.
E E

418
[BOOK II.
THE FORMATION OF DEPOSITS.
"The enormous open work of Carclaze, near St. Austell, is an object of
no ordinary interest. The traveller may there see the operations of the
miner carried on in the light of day, without being compelled to descend a
hundred fathoms below the surface of the Earth, and then to crawl into a dirty
dripping cavern. The works are excavated in a variety of decomposing
Stanniferous Granite and schorl rock. The chief constituents are quartz,
felspar, schorl, and oxide of tin, with occasional specs of mica. Throughout
the whole extent of the excavation we may trace a succession of parallel
veins of schorl rock, which do not in any degree partake of the decomposition
of the metalliferous beds, and appear both in their range and dip to cor-
R
Fig. 69.-Carclaze Tin Mine.
respond exactly with the beds of Killas in the immediate neighbourhood."
(See Figs. 69 and 70, the first representing this remarkable excavation in
perspective, the other in plan, drawn carefully to scale.)
Professor Sedgwick appears to be greatly in favour of the view that most
of the veins in Cornwall are veins of segregation. He says, especially
referring to this excavation:-
"In all the crystalline Granitoid rocks of Cornwall there are also many
masses and veins of segregation. Such are the great contemporaneous masses
and veins of schorl rock, and some of these are metalliferous. The decomposing
Granite of St. Austell Moor is traversed and sometimes entirely superseded by
innumerable veins of this description. Upon these lines of schorl rock there
is often aggregated a certain quantity of oxide of tin, which sometimes.
diffuses itself laterally into the substance of the contiguous Granite." The con-
CHAP. IV.]
PLAN OF CARCLAZE TIN MINE.
419
cluding passage of this quotation is very obscure. That a mind of the power
of Sedgwick's, which in a remarkable manner appeared always equal to the
penetration of the obscurity of an hypothesis, should yield itself to the idea
that any separate action of secondary diffusion took place in the masses such
as he is clearly describing, is not easily understood.
Dr. Boase, an equally cautious observer,* remarks: "The upper part is
much decomposed, but beneath it gradually becomes more solid and perfect.
It is traversed with innumerable strings and bunches of schorl and schorl rock,
which abound in tin ore. These irregular veins are evidently contemporaneous
with the Granite, for they are so intimately blended together that in order to
obtain the ore both veins and rock require to be stamped and washed."
Carclaze Pond
Mag. 1877.
1
B
Pond
Tramway
Clay Stream
Shed where
the laborers
dine& sheller
Pond
A. R. P
Contents 13.1.37
Cottage
Shaft
C
A
2
Shaft
Stamping
Mill
StamAng Mill
Stamping
WMELL
Stream.to
TE
Little Carclaze
ATE
Conal
Tramway Tunnel
Тосса
Coccasion
Underground
to pit
Stamping
Fig. 70.-Plan of Carclaze.
R. P.
15.
Mr. Hawkins remarks +: "Like all veins which traverse those hills they (the
lodes of which were at one time quarried) are composed of quartz and schorl,
and carry more or less tin, which are so united with soft and hard growan
that no doubt can be entertained of their contemporaneous origin."
If we enter Carclaze mine from the south the Granite and the Slate pass
almost imperceptibly into each other through a medium of compact rock
mostly composed of schorl and felspar which are often mixed, and occa-
sionally in alternating laminas. In some places, however, this rock is
quartzose, whilst in others the quartz assumes a veined structure.
When mining operations were actively carried on here, a stamping-mill,
worked by steam, was erected at the very bottom of the excavation. The old
* "Royal Cornwall Geological Transactions," vol. iv. p. 238.
† Ibid.
EE 2
420
[BOOK II.
THE FORMATION OF DEPOSITS.
steam-engine still remains, but it has long been out of use. Now several
water-wheels propel the machinery for crushing the tin stones. Within
memory the adit level was navigable, and the tin was removed in a boat.
The Granite of Cligger Head, which is in many respects remarkable,
possesses much in common with the Granite of Carclaze mine. It is traversed
by narrow veins of quartz, and both the rock and the veins contain tin ore.
The action of the sea saps the base of the cliff, and large portions of it fall
every winter.
Dr. Clement Le Neve Foster* has well described analogous formations at
Wheal Prosper and Michell, and also at Mulberry, a few miles from Bodmin.
He states that the Granite is traversed by numerous branches or veins running
north 7° west, dipping about from 80° to 90° west, and varying from mere joints
to veins 4 or 5 inches in width, rarely more than a foot apart, in fact gene-
rally only a few inches. Many of the veins preserve their independence for
a considerable distance without intersecting other branches; but at the same
time it is easy to find junctions both in the dip and in strike; sometimes
also two adjacent strings may be connected by a "floor" or bed of tin fol-
lowing the stratification. In addition to oxide of tin the beds contain quartz
and a little arsenical pyrites and wolfram. The appearance of the north
end of the quarry will be readily understood by reference to Fig. 71, which
shows the general mode of working.
Men, standing at A, bored holes and blasted them, which threw the rock
.0
A
20
B
Scale 120 60 inch-a foot.
40
60
80
100 Feet
Fig. 71.-Section of Mulberry Mine.
to B, under which a level has been
driven with an opening C, usually
closed by a hatch. A waggon is run
in, and by opening the hatch it is
filled without labour. As the face of
the quarry gets farther and farther
north from the removal of a succes-
sion of more or less vertical slices,
the level is driven on ahead and
another hatch made.
The stuff is trammed to a dis-
tance of about a quarter of a mile to
stamps worked by water power;
and even at present prices this poor
tin-bearing rock, containing not
more than 7 lbs. of tin to the ton of
stuff, or about one-third per cent., is made to pay all expenses.
Dr. C. Le Neve Foster also well describes a mass of Greisen (altered
Granite) at Hensbarrow, which cannot fail to be of interest.
<<
Carrigan, about two miles east north-east of Roche, on the northern edge
of the great Hensbarrow boss of Granite, affords the finest display of Greisen
in the county of Cornwall. The mass of Greisen wrought at Carrigan quarry is
known for a width of 50 yards and a length of 100 yards and a depth of 60 feet.
On the south-east side it is bounded by a large clay vein or flucan, and
on the north it disappears under the alluvium of the neighbouring valley.
* "Quarterly Journal of the Geological Society" for August, 1878.
CHAP. IV.]
FRAGMENTS OF ROCK IN LODES.
421
The rock is a mixture of quartz and mica with a good deal of schorl, some
Gilbertite, and a little iron pyrites, fluor, and Cassiterite. The mass is tra-
versed by a number of so-called leaders, which are quartz veins with tin
ore, schorl, Gilbertite, and clay, dipping 85° south, and running east 7° north.
Very often they are 1 inch or 2 inches wide, and from 1 foot to 6 feet apart.
Occasionally the leader adheres to the enclosing rock (country) by one side
only, and has a clay vein on the other. On washing the clay, broken crystals
of Cassiterite are generally found, proving that since the deposition of the
tin ore, in the fissures, there has been a movement of the walls. When tin
was at a higher price, this mass of greisen and tin veins was quarried and
stamped on a large scale; in fact, 27,500 tons of rock were stamped, yielding
64 tons of tin ore, or 5.2 lbs. of tin (black tin) per ton, say per cent. It was
expected that the wholly virgin ground would produce 8 lbs. of tin ore per
ton. As the rock is very much harder than the Killas of Mulberry, it cannot
be profitably worked at present prices."
West Rosewarne and other Mines.-The mine first named does not exhibit
any mining operation of a novel character, nor is it remarkable, beyond other
mines, for peculiarities in the lodes. There are, however, some phenomena
deserving attention both in West Rosewarne and the neighbouring mines.
These are, the presence in the lodes of matter which has been derived from ex-
traneous sources, which serve to advance our knowledge of the age of veins.
At the 74-fathom level in the West Rosewarne mine some large Granite
boulders were met with, some years since, sometimes in the lode, and occa-
sionally both in the lode and the country. The lode at this mine is almost
entirely made up of breccia (principally angular fragments of Killas); and the
66 country" in which the boulders occur is also itself of a brecciated and con-
glomeratic character, and this to a curious extent. These boulders and
pebbles range from an inch up to 12 inches in diameter, and are called by
the miners "bullies," the small ones being called "young bullies" and the
larger ones "grown bullies." As a general rule, these rounded pebbles and
boulders seem to be found in the "country" and in the neighbourhood of
the lode, but not usually in the lode itself, nor in the country at any distance
from the lode. These conditions exist over the whole of the surrounding
country, conveying to the mind the idea of its having been subjected to some
violent disturbance. The area which presents this confused condition is
limited in extent, and therefore the conclusion is forced on the mind of the
observer that some peculiar force, probably due to pent-up vapour or steam,
has been suddenly liberated, which thus rended and lifted the rocks forming
the country.
Of Relistian mine, Mr. J. Carne says: "Here, at a depth of 100 fathoms
below the surface (which is not higher than the surrounding country),
a mass of pebbles was discovered in the tin lode. The pebbles are of Slate,
the same as that of the country. In the crevices between the pebbles,
and connected with the cementing substance, are oxide of tin and yellow
sulphide of copper, the former always crystallised, the latter never.
Mr. W. J. Henwood confirms this: "At Relistian the Slate contains
numerous spheroidal concretions, some of them are compact, others schistose
Slate, and others entirely of quartz."
422
[BOOK II.
THE FORMATION OF DEPOSITS.
In Herland mine, about 110 fathoms deep, there were numerous nodular
masses of Granite, which consist of a base of felspar with some quartz
and a little mica. They were fine and decomposing, varying in size, and
whilst some are not larger than a hazel-nut, others are two or three feet in
diameter (Henwood).
Mr. H. C. Salmon, who appears to have examined these boulders with
much care, comes to the conclusion that "the whole bearing of the evidence
shows that the boulders must be taken as having been subsequently intro-
duced, and most probably through fissures from the surface. Mr. Salmon
concludes his notice of these phenomena in the following words: "In
searching for an elucidation of the obscure and complicated causes under
which metalliferous lodes have originated, nothing is more important than to
endeavour to ascertain what periods of time have elapsed between their
formation and that of the eruptive rocks with which they are generally
associated.'
""*
In the formation of fissures, it is evident that the active force by which
they have been produced must have propagated a wave, by which the eleva-
tion and depression of the surface of the country to an unknown depth was
effected. Of this, the veins are a sufficient evidence. In producing the larger
rents, splintering of the rocks must have taken place, and the fragments
broken off must have fallen into the veins. Beyond this, during the period
in which the deposition of the ores, from whatever cause, was taking place,
there must have been constantly fragments splitting off from the sides of the
cracks, and these are no doubt the angular fragments which we find imbedded
in the matter of the lode or enveloped in the metalliferous ore.
During one geological period-probably the Glacial epoch-by the
breaking up of the Chalk formations, flints were scattered over all Western
Devon and Cornwall, and they are found even at the Scilly Islands.
The late Mr. Samuel Higgs, jun., found a chalk flint at the bottom of a
"vug," or cavity, of the so-called New lode, at the 130-fathom level, in Balles-
widden mine, surrounded with decomposed felspar and quartz. The vug was
about 18 inches square, and the lode in this place 7 feet wide. Similar flints
are distributed over the surface on Solger's Croft, near Carn Kenidjack.†
Water-worn stones have also been found in South Wheal Frances. They
were discovered a little above the 82-fathom level-about 105 fathoms from
the surface-near the middle of the vein, which at this point was chiefly
composed of rich copper ore.‡
Organic Remains in Mineral Veins.-Mr. Charles Moore § published a
memoir on mineral veins and their contents, which will form an instructive
addition to the descriptions already given.
The views entertained by this observer are beyond our purpose. His in-
vestigations into the evidence afforded by fossils of the ages of veins is the
* Consult a paper by Joseph Le Conte in the "American Journal of Science" for July, 1883. Mr. Le
Conte's hypothesis supposes the water, percolating the rocks, penetrates to great depths, acquires a high
temperature, and, dissolving earthy and mineral matters, exhibits solfataric action, and fills the fissure
through which it is forced with the earthy and metalliferous matters forming veins.
"Transactions of the Geological Society of Cornwall," vol. vii. 1865.
John Rule, “Transactions of the Geological Society of Cornwall," 1865.
"Report on Mineral Veins in Carboniferous Limestone and their Organic Contents." By Charles
Moore, F.G.S. ("Report of the British Association for the Advancement of Science" for 1869.)
CHAP. IV.]
ORGANIC REMAINS IN LODES. ·
423
only portion of his report with which it is intended to deal. Mr. C. Moore
introduces his subject by stating that Sir Charles Lyell mentions* that
M. Virlet had found a gryphaa in a lead mine near Semur in France, and
that a madrepore had been seen in a compact vein of cinnabar in Hungary.
He then continues:
"One reason for the non-discovery of organic remains has arisen from
their being generally of small size, and that the vein-stuff in which they have
to be sought for is often of a very intractable character, resisting the action
of the water, by which it has to be dissolved, before they can be washed out
of it, after which the residuum requires almost microscopic examination for
their separation. The organic remains thus obtained are occasionally even
more varied, as regards genera and species, than if they had been derived
from a given horizon of stratified deposits, arising perhaps from the length of
time within which the fissure might have been open and the necessarily
mixed condition, consequent upon the filling of the vein. Some from the
Carboniferous Limestone itself are associated with those which are foreign or
derived. In the case of the Charterhouse mine on the Mendips, those which
are of Liassic age, and consequently derived from that rock, are in the
proportion of about 90 to 30 from the older rocks within the walls of which
they are found. In the Carboniferous Limestone districts of Holwell and
Frome, Rhotic and Liassic organisms are also in large proportion; and
the same may generally be said, throughout the Mendip range and South
Wales. In North Wales and the North of England, on the contrary, Car-
boniferous Limestones are the most frequent; those of later age are the
exceptions, some of these being Entomostraca of Permian species and Forami-
nifera, which have a long range upwards."
Charterhouse mine shows that a considerable time must have elapsed
within which the lodes remained more or less open, and during which various
oceanic influences were at work. At 270 feet-the lowest depth of the
Charterhouse shaft-there is found a deposit of blue clay 10 feet in thickness
which yielded a considerable number of Lias fossils (Mr. Moore enumerates
75). This, on the same level, changes from a homogeneous marl to patches
of a more conglomerated material with enclosed water-worn pebbles. Higher
up the vein it becomes a dense conglomerate. Above this sandy deposits
occur, which, when washed, are seen to be almost entirely composed of the
detached stems of encrinites very much abraded, with small washed pebbles
of hæmatite iron ore, " showing that, after the deposit of the Lias in the vein
below, a denudation of the Carboniferous Limestone had been going on,
and above this again occurred calc-spar and the largest deposit of lead ore."
In addition to the 75 Lias fossils, a list of 28 are given by Mr. Moore
as belonging to the Carboniferous Limestone.
"In other mining districts organic remains are generally less plentiful than
in the Mendip area, but I have not failed to detect them, more or less abun-
dantly, except in one instance-in that of the Cononly mine, in the Airdale
district." The following list has been abstracted from Mr. Moore's report :—
Keld Head Mines, Wensleydale.-Organisms rare at 48 feet, but En-
crinites, Involutoria, and serpula-like tubes detected. At 90 feet Encrinites
"Elements of Geology," p. 762.
424
[BOOK II.
THE FORMATION OF DEPOSITS.
very abundant with galena and iron pyrites. At 192 feet Encrinites abundant.
At 210 feet Valvata Anomala, Entomostraca, Echini, and Encrinites. At 240
feet, West Bank vein, Foraminifera, Encrinites, and Serpula, Bryozoa, &c. At
450 feet, with galena, blende, iron pyrites, &c., Euomphalus, Entomostraca,
Encrinites, Echini, Serpula, Terebratula, &c., abundant. A list of 57 fossils
found in Keld Head mines is given.
Fallowfield and Brownley Hill Veins.-The latter at 1,400 feet and the
former 100 feet above sea-level, and at depths from 90 feet from surface
to 600 feet, a list of 23 fossils is given.
Grassington Mine.-From the 24-fathom level to the 45-fathoms, at
the height of 1,300 feet above sea-level, a list of 51 organic remains is given.
Alston Mines (1,240 feet above the sea-level).-Twenty-nine fossil remains
have been collected from the vein.
Weardale Mines.-Twenty-two varieties of organic remains have been
collected.
The Allenhead Mines have yielded 32 specimens of different organic
remains from its various lead lodes at several depths.
The White and Silver Band Mines give, from the lead lodes, a list of 19
organic remains.
Coldberry and Redgroves, in Teesdale, yield 20 varieties.
Mount Pleasant Mine, near Mold, in Flintshire, yielded 24 fossil varieties
to a careful search.
Mr. Moore concludes his interesting paper in the following words:
"Not the least important fact in my mine explorations has been the
discovery of a land and freshwater fauna. Until I obtained the three genera
of Helix, Vertigo, and Proserpina, with the freshwater genera Planorbis and
Valvata in the Charterhouse mine, the only known terrestrial shell was
the Papa-Vetusta. To the above genera I have now to add those of Hydrobia,
Stoastoma, Lithoglyphus, and Pisidium from the mines of the North of
England. There is thus the fact of the presence of nine genera of land and
freshwater shells in the lead veins of this country."
In addition to the list of organic remains [given as an appendix to Mr.
Moore's report], numbering about 112 species from the North of England and
North Wales mines, "eight, which are not common, have been obtained from
Weston, and to these again are to be added 89 from Charterhouse, so that in
true and workable mineral veins I have found 209 species. I have discovered
the oldest known Mammalia, the oldest land and freshwater Mollusca,
about 52 species of fish, and about 8 of Reptilia."
Clifford Amalgamated Mines and others in Gwennap.—The Wheal Clifford,
from which the present name was adopted, was included with the Consolidated
and United mines in 1819. These mines are situated about a mile south-east of
the village of St. Day, about seven miles from the shipping port of Portreath,
and about four miles from Restronguet Creek, which opens into Falmouth
Harbour. The Consolidated mines, as they were formerly called, included
within their sett (as the ground included within the boundary of a mine is
provincially termed) Cusvea, Wheal Fortune, Wheal Lovelace, East Wheal
Virgin, and West Wheal Virgin. These were all worked as separate mines
until towards the end of 1818, when the union was first contemplated; but
CHAP. IV.]
THE GREAT GWENNAP ADIT.
425
the arrangement was not completed until the following year. The "sett"
of the Consolidated mines extended from near the mouth of the great
Gwennap adit eastward, to within a short distance of the village of Car-
harrack westward, being about 1,500 fathoms, or a mile and three-quarters,
in length, and averaging about 300 fathoms in breadth. To this sett the
United mines was joined in 1824, which included Ale and Cakes mine and
Poldory, and still more recently Wheal Squire has been added. The
United mines sett adjoins the Consolidated sett to the south for nearly two-
thirds of its length. To the east the boundary is formed by an imaginary
line crossing the country to the west by the "great cross course,"
"* and to
the south partly by a stream running nearly parallel to that which bounds
the Consolidated mines to the north. The area included in these combined
mines is about 1,200 acres, or nearly two square miles. Some idea may be
formed of the mineral wealth of this tract, by stating that within the last
eighty years it has given metallic wealth to the amount of £6,000,000 sterling.
The ores are generally accompanied by iron and arsenical pyrites, and
occasionally by zinc-blende, and other minerals. The veinstone is almost
entirely quartz intermixed, with the copper ore Gossan (oxide of iron), which
occurs generally on the backs of lodes.
The singular cavities called in Cornwall Voughs (pronounced Vughs† or
Vugs) are seen in many of the lodes. They vary in size from two or three
inches to as many feet. Their interiors are usually lined with crystallised
quartz and pyrites, but they occasionally contain rare mineralogical specimens.
The lodes which are productive, or rather the portions of them which
are so, are frequently of great length, often from 206 to 300 fathoms
long. The "courses of ore" often extend from 30 to 80 fathoms and more
in length. It is commonly believed that wherever a lode is rich, if there
be another lode near it having nearly the same direction and in the same
country, whether in Killas or growan (disintegrated Granite), or even in an
Elvan course, it is probable that the second lode will be found rich in that
part which is opposite to the rich part of the first lode. "This is not a new
doctrine. The phrase ore against ore is probably of earlier date than the
present generation of miners" (Carne).
(Carne). "The occurrence of the richer
portions of parallel lodes on the same meridian has been long known and
acted on, and indeed seems to have been first recognised in this district"
(Henwood).
One of the most remarkable works in connection with those mines is the
great adit which empties itself into Carnon Valley a little above the high-
water mark. This was commenced in 1748 by Mr. Williams, who was
then manager of Poldice mine. It was begun near Bissoe Bridge, and was
extended to the western boundary of Poldice in less than twenty years, and
the expense of this portion of it was defrayed by the adventurers in that
mine. It was subsequently driven to other mines, all of which it unwatered.
* The great cross course, which traverses the mineral district of Redruth, extends quite across the
country, being seen in the cliffs of the English Channel and in those of the Bristol Channel. Its direction
is nearly that of the magnetic meridian, and the distance it may be traced is about twelve miles. It is
chiefly composed of quartz and clay, but in some places it extends to the width of thirty feet, and is filled
in with disintegrated Granite, derived, no doubt, from the neighbouring hills.
+ "Fogans," applied to caverns in the cliffs in West Cornwall, and "gogofau," or "ogofau,” as
applied to the Roman gold mines in Carmarthenshire, are evidently forms of the same term.
426
[BOOK II.
THE FORMATION OF DEPOSITS.
The length of the adit with the various branches amounts to about 26,000
fathoms, nearly 30 miles, and the greatest length to which any branch
has been extended from the adit mouth is at Cardrew mine, which is about
4,800 fathoms, nearly 5 miles. The highest ground it has penetrated is at
Wheal Hope, where the adit is 70 fathoms deep at Chilcot's shaft, and is
deeper in the branches extending from thence.
The general character of the rocks of this district has been already
described. Some of the masses of Elvan, however, require additional
notice. The principal body of Elvan known in the Consolidated sett
traverses Coisgarne Downs in an easterly and westerly line. This is a
large irregular mass of great width and extent, penetrating the Killas in
various directions. Elvan is also known in several other parts of the United
mines and in Wheal Squire. These Elvans vary in texture and appearance.
Their colour is usually a light brown, but often they are greenish or greyish,
and in texture and composition not very unlike Granite.
The mineral veins or lodes worked in these mines are large and regular
and very numerous. There are about eight or ten which may be called
principal lodes, besides a great number of smaller lodes or "branches"
either running parallel to or crossing the former. The direction of the
principal lodes is either very nearly east and west, or a few degrees north
of east and south of west. That of the smaller ones or contre (caunter) lodes
is nearly north-east and south-west. The width of the principal lodes in the
Consolidated mines averages about 3 feet, but occasionally they reach 4 or 5
and even 8 or 10 feet. In the United mines 4 or 5 feet is the usual width of
the main lodes, the branches in both mines rarely exceeding from 12 to
18 inches.
The underlie of the principal lodes is towards the north; but the
underlie of the smaller lodes is generally south, thus occasioning them to
intersect the former in depth. The chief and most valuable produce of these
lodes is copper pyrites, or "yellow ore." Native copper, peacock copper,
purple copper, grey copper, the blue and green carbonate of copper, and the
red oxide of copper, are also found in these mines. All these varieties may
be regarded as changes effected by slow chemical action upon the original
sulphide of copper, and of iron pyrites. In the United mines native copper
has been raised in greater abundance than is usually the case with this
metal.
It is necessary that some attention should now be devoted to a considera-
tion of the most remarkable Consolidation of mines which ever existed.
Three lodes run through the entire length of the mines in Gwennap, inter-
sected by eighteen smaller ones in different parts. The principal lodes run
about 10° north of west and south of east. The others vary considerably, but
generally their direction is more to the north of west and south of east.
The larger lodes vary from a width of 10 feet to a few inches, the others
from a few inches to 3 feet. They underlie north, with the exception of seven
of the smaller lodes, which underlie south.
In July, 1845, there were 23 shafts in use, and a great number of
others out of use. At that date 625 miners were employed underground,
and 146 boys; which at the surface, men and women, boys and girls,
CHAP. IV.] THE UNITED AND CONSOLIDATED MINES.
427
amounted to 904. In 1815 2,982 tons of copper ore were raised, giving
8 produce for copper. In 1818 11,476 tons of copper ore of 8 produce.
The greatest quantity of ore raised in any year was in 1845-14,374 tons,
with a produce of 7.
In 1824 the United mines were abandoned. The drainage, which had
been effected by four steam-engines, was then suspended, and the water
allowed to rise in the mines. The bottom workings of that part of the mine
called Ale and Cakes were about 210 fathoms below the surface. Even-
tually it was determined to pump the water from the United mines, and to
work them again on an extensive scale.
In 1862 the United mines were incorporated with the Consolidated mines.
The following is a succinct statement of the condition of the United mines
at this time:
Ale and Cakes is the deepest part of these workings, and has been extensively
worked both on the main and the branch lodes for about 400 fathoms in
length. The adit is cut at about 40 fathoms in depth from the surface, and
workings extended 170 fathoms below it, or 210 fathoms from the surface.
This mine occupies an elevated situation, being on the gradual declivity
of a range of hills on which the Consolidated mines are situated, and near
their opposite escarpment, which declines here both to the south and to the
west.
Phillips* informs us that in some of the deepest workings pieces of
copper pyrites of a mammillated structure were found loose in the vein. These
masses were from 2 to 3 inches long, and exhibited the appearance of having
been rounded by attrition.
Poldory adjoins Ale and Cakes to the westward, and has been extensively
worked, both on the main lode and on the smaller ones, for near 300 fathoms
in length, and in parts to 110 fathoms under the adit. A small building on
this mine is said to have been the engine-house of one of the first steam-
engines erected in Cornwall. This building is about 15 feet square, so the
engine must have been a very small one.
East Ale and Cakes has been worked to about 80 fathoms below the sur-
face, almost entirely on the old lode to which the adit of the United mines
is extended.
Wheal Squire adjoins Poldory to the west, the two being separated by the
great cross course, which is here from 18 to 20 feet wide, and heaves the lodes
for a distance of 20 fathoms. This mine was at one time very productive,
but after being idle for some time it was added to the United mines.
"The most remarkable feature in Wheal Squire is the numerous dis-
locations of the lodes of cross courses, of which no less than eight were known,
several of them being branches of the great cross course. In some cases
the heaves do not exceed 3 or 4 fathoms, they are frequently as much as
18 or 20. It is worthy of notice, and one strongly exemplifying the action
of denuding causes, that the surface of this mine is nearly a perfect level,
and presents not a single trace of the tremendous subterranean convul-
sions which have at different periods affected it to an extent of which there
are but few parallels in so limited a space of ground" (Burr).
* William Phillips's "Introduction to Mineralogy.”
428
[BOOK II.
THE FORMATION OF DEPOSITS.
The union of mines known as the Gwennap Consolidated mines commenced
working under that title in 1819, but the Mining Record Office has returns
from 1815. Those were as follows:-
Ore.
1815
1816
•
•
322
722
•
1817
•
443
1818
429
1819
•
·
774
•
•
Value.
£ s. d.
2,082 II 6
Produce.
732
•
4,025 13 6
7%
•
2,326 7 6
83-
2,974 17 6
78
7,258 9 6
9
The union of the mines now took place, and we find an increase com-
mences in 1822, which steadily advances :-
1822
1827
•
1832
1837
1842
Ore.
12,861
13,252
•
15,523
19,210
11,617
•
Value.
£ s. d.
80,311 I 6
6
92,107 II
108,886 6 6
133,024 8 6
73,558 6 o
•
Produce.
88
9
7/
ocko
9965
In the Appendix to this volume will be found a general set of tables
giving much information as to the cost of mines from the earliest obtainable
accounts, and some interesting particulars of the cost of working large
and important mines, furnished by the proprietors.
A section drawn across the parish of Gwennap presents the remarkable
series of lodes and Elvan courses named in the following list :-
WHEAL UNITY
North Lode
POLDICE.
WHEAL MAIDEN
CONSOLIDATED MINES
UNITED MINES
South Lode
James's Tin Lode
Singer's Copper Lode
Tin Lode
Field's Lode
Little Lode
Tremayne's Lode
Martin's Lode
North Lode
Mammell's Branch
Bray's Branch
•
Wheal Fortune Lode.
Taylor's Lode
Deeble's Lode
Kitto's Branch
Hot Lode
Old Lode
•
Middle Lode
South Lode
California Lode
•
E
Elvan course.
Elvan course.
•
Elvan course and branches.
SOUTH CLIFFORD
WHEAL ST. AUBYN
Although the whole of the parish of Gwennap is metalliferous, Job's dis-
trict, as it has been called, has proved the most productive. Before the con-
solidation of the mines, this section was worked as East Wheal Virgin. The
deepest points of these workings were near Job's engine-shaft, which is situated
about midway between Davey's and Terrill's, and extended to 150 fathoms
below the surface, or 1 10 fathoms under the adit. In the workings at this time
a 90-inch cylinder was placed on Job's shaft, and pumps were fixed also in
Terrill's shaft, and the two sumps were carried down from their former depth
of 90 fathoms under adit to the depth of 135 fathoms.
CHAP. IV.]
LENGTH OF LEVELS-DEPTH OF SHAFTS.
429
The levels in this district were extended considerably from the 100-fathom
or former deep level to the 210-fathom level, and the Consolidated mines were
commonly spoken of as "a new mine under the old one.”
Between the 110 and 120 fathom level, a little to the west of Taylor's
shaft, a very extensive vough, or cavern, was discovered, the size being much
greater than is commonly observed, being nearly 40 fathoms in length and
from 1 to 2 fathoms high; the direction was nearly horizontal, the lode both
above and below producing good ore.
The necessity of an additional shaft in this district for drawing ore and
stuff being sensibly felt, it was resolved to sink one from the surface with
all possible expedition. The new shaft was to be called Francis's shaft,
Captain William Francis being then the principal agent of the mine. For
the dispatch with which this shaft was executed and the precision of the
work, which was unrivalled, this work was in its time remarkable. The
work was begun in March, 1839. The situation chosen was north of the
other shafts and on the line of the old lode, which it was to intersect in depth,
the underlie being 18 inches per fathom. Cross cuts were driven from the
adit-the 40, 70, 100, 120, and 135 fathom levels-and while the upper portion
of the shaft was sinking below the surface the operations of sinking and rising
were carried on from each of the cross cuts mentioned, and also from the 150
and 160 fathom levels, which were already in the proper line, the ground
thus being opened in fifteen different places at once. The total depth of the
shaft was about 205 fathoms, and on the 31st December the last bar of
ground which intervened between the surface and the bottom was holed.
Thus in about nine months and a half a perfect shaft, exceeding 200 fathoms
in depth, was sunk from the surface. So great was the accuracy and skill
with which the diallings and measurements for this work were conducted,
that after the necessary squaring, Francis's shaft was as perfect as if sunk
from the surface only, nor could any irregularity be observed at the junctions
of the different portions. The aggregate extent of the earlier workings upon
the principal lodes was for a length of 1,700 fathoms, and their depth, on an
average, to the 90-fathom level. Assuming the levels to have been driven
regularly at every 10 fathoms (which was not strictly the case), this length
will give us 17000, fathoms, or nearly 20 miles.
The aggregate length of the workings in 1835, on the same principal lodes,
was 1,200 fathoms, and the depth to which they were carried was on an
average to the 200-fathom level. These levels were driven very regularly at
10 fathoms apart, consequently 12,000 fathoms were driven during those
workings. Cusvea-which became one of the Consolidated mines—was
almost a new mine, and here for 200 fathoms the levels were driven regularly
from the adit to the 140, making a total of 2,800 fathoms, which, including
the ground opened east and west of the deep workings, may probably be
called 3,000 fathoms, making a total extension of levels during these
workings of 15,000 fathoms; or which, taking into account the distance.
driven upon the smaller lodes and branches, and also in cross cuts, will
amount to near 17,000 fathoms, or about 19 miles, thus making the
aggregate length of levels in 1835 as more than 33,000 fathoms, or nearly
40 miles. Considering the depth of these shafts in the same manner, we
430
[BOOK II.
THE FORMATION OF DEPOSITS.
may consider these to have been, previous to 1835, about 45 in number
(exclusive of shallow ones), and averaging about 100 fathoms in depth,
making an average depth of 4,500 fathoms. Twenty of these shafts were
sunk during Captain Francis's workings, on an average about 80 fathoms
each, making 1,600 fathoms additional. During this period ten new shafts
were sunk to a depth averaging 250 fathoms, making about 4,000 fathoms,
which, added to the former, gives between 8,000 and 9,000 fathoms, or above
10 miles, as the aggregate depth of the shafts in the Consolidated mines.
Within twenty years from the union with the United mines, 37,330 fathoms
were driven horizontally, and about 1,800 fathoms sunk in winzes and shafts.
This makes the extent of the Consolidated mines at that time as being 63
miles.*
At the end of 1837, the mine having been then at work eighteen years,
the account given below was printed.†
Quantity of ore raised and sold, 259,420 tons, the value of which was
Paid to the lords of the land as dues
•
£1,845,326
76,888
Cost of working the mines
•
1,450,836
Of which was paid for labour only
758,590
capital (£65,000)
•
248,000
And the profit paid to the adventurers, besides the return of their
The New Consols, subsequently named Wheal Clifford, was united to the
Consolidated mines, including the United mines, and this extensive sett was
known as Clifford Amalgamated mines.
Wheal Clifford is situated to the east of the United mines. The works at
this mine were never very extensive. For example—
In 1833 the mine produced 67 tons copper ore.
1852
1861
618
6,301
In the following year the extension arising from joining the three setts
together, under the title of the Clifford Amalgamated mines, gave rise, of
course, to greatly increased returns, which, however, the following statement
will show were not very lasting :-
1862
•
Ore.
14,322 tons
1863
1864
14,273
15,180
""
•
""
Copper.
855 tons
896
965
Values.
·
£68,475
Produce.
6
•
68,667
61
""
79,702
1865
15,111
""
1866
13,961
1867
12,460
883
784
820
""
·
66,999
""
50,320
55
""
""
•
55,825
1868
10,732
•
1869
1870
8,309
2,080
""
639
587
""
•
40,878
""
35,168
120
""
6,743
•
•
16
59 16
716
5/2/2
On the 29th June, 1870, these important mines ceased working.
The latest account available, prior to the cessation of operations in this
extensive set of mines, informs us that the engine-shaft was several fathoms
under the 212-fathom level, and that the lode in the shaft was 3 feet wide,
producing stones of ore. By extending the 212-fathom level eastwards, it
was found that the lode divided, 7 fathoms east of the division, which had
been previously noticed in the 200-fathom level, into two regular lodes. The
* John Taylor, "Reply to Observations on the Statement of the Committee of the Consolidated
Mines Adventure," 1838. (Printed for private distribution.)
+ "Statement of the Committee of the Consolidated Mines Adventure."
CHAP. IV.]
THE HOT LEVEL IN UNITED MINES.
431
north lode in the end was 4 feet wide, worth 8 tons of ore the fathom, while
the lode to the south is 3 feet wide, but produced only 2 tons of ore per
fathom. It is not easy to account for this remarkable difference in what may
be considered as two branches of the same lode. At the same time there
were two stopes working in the back of the 212-fathom level, giving 14 tons
of ore to each fathom of ground. The 212-fathom level was driven west of
the engine-shaft, the lode in the end falling off to 2 feet wide, with occasional
stones of ore. In the 200-fathom level driving west the lode was 7 feet wide,
giving 10 tons of ore per fathom, and two stopes working in the bottom of
the 190-fathom level gave 15 tons of good copper ore per fathom each.
The lode in the 220-fathom level driving east from the United mines
boundary was 9 feet wide, yielding 15 tons of copper ore to every fathom.
Three stopes were working in the bottom of this level, between the end and
the boundary, giving 8 tons of ore per fathom each; and two stopes were
working in the back of the 220-fathom level, worth 15 tons of copper ore per
fathom, and all the tribute pitches were producing the usual good quantity
of ore.
In the United mines district the lode in the 230-fathom level, driving east
from Garland's engine-shaft, was 4 feet wide and entirely unproductive.
Driving west from Taylor's engine-shaft, the lode produces a few tons of ore.
The lode in the 220-fathom level, driving in the same direction, is 4 feet wide,
and gives 6 tons of ore per fathom, from which there is a spring of hot water
almost continuously flowing. The new works in the United mines district
were only occasionally productive. A new shaft, called Buzza, was sunk to
the 50-fathom level, and the lode was producing copper ore at the rate of
6 tons to the fathom.
Five pitches were working in this part of these mines at from 2s. 6d. to
6s. 8d. in the £ on tribute. In the 194-fathom level, east from Hawke's shaft
on the Great South lode, the ends were generally unproductive.
In the Poldory district and at Wheal Moor sundry trials were made, but
none of them proved very successful. From West Poldory to the eastern
end in Wheal Clifford there was a course of ore dipping at an angle of about
45°, more than a mile in length. In relation to the heat in these mines
it has been asked, “Is it not the constant friction of the water filtering
through these long and deep courses of copper ore and mundic that causes
the heat of the water, producing a kind of natural sulphuric acid manufactory,
but not carrying out the process fully?"
The level in the United mines in which the heat was the greatest at that
time (1864) was from the 190-fathom level under the adit to the 230-fathom
level. The temperature of the water was then as high as 126° Fah., the air
being 121° Fah. At the 208 fathoms the air was 114° Fah. There was a
course of ore in this level which was horizontal in one continuous length for
150 fathoms, then there were short breaks comparatively poor, and then
fresh courses of ore. The ore being all removed, this level became dry and
cold. This looked like chemical action.
The machinery employed in this concern for drainage and other purposes
greatly exceeded any similar combination in the world. Eight large steam-
engines, their dimensions varying from ninety to sixty-five inch cylinders, and
432
[BOOK II.
THE FORMATION OF DEPOSITS.
another of thirty-inch cylinder, were employed for pumping. Eight steam-
engines of about twenty-inch cylinders were employed in drawing ore and
stuff. Beyond these there was a water-wheel, forty-eight feet in diameter,
for pumping, one about forty feet for driving machinery, and five smaller ones
for stamping and grinding the ores.
Besides these several horse-whims were
employed. A writer * says: "Calculating the force constantly exerted by this
stupendous accumulation of mechanical power when working at a moderate
rate, it may be stated as equivalent to the work of 1,000 horses, which is,
however (supposing that it were possible to employ animal power), equal to
three relays of horses, required in the twenty-four hours, besides an extra
stock for casualties-making the actual number of horses to which the engine-
power at these mines is equivalent more than 3,000. It should, however,
be taken into account that horse-power' so termed by engineers, consider-
ably exceeds the strength of an ordinary horse (according to some authorities
by one half), and bearing this in mind, we may probably say that the engine-
power employed in these mines is equal to the work of nearly 5,000
horses, and were it exerted to its full extent it would probably be equal to
double that number."
The number of persons usually employed at those mines when in activity
was about 2,500, of whom between 1,400 and 1,500 were miners working
underground. It will be interesting to preserve the
Statement oF THE CLIFFORD AMALGAMATED MINES' ACCOUNT, For November
AND DECEMBER, 1863.
By amount of Wheal Clifford ore sold 3rd and 31st December, 1863
Consols ore sold 3rd December
Ditto tin
•
•
£ S. d. £ S. d.
8,074 4 5
373 15 I
42 4 3
8,490 3 9
412 7 5
Deduct Lords' dues
United Mines ore sold 26th November and 24th December, 1863,
and 28th January, 1864
Ditto tin sold
Sundry receipts
""
Registration fees
·
DEDUCT.
8,077 16 4
•
4,942 II
I
91 7 5
52 3 10
7 10 O
5,083 18 6
59 13 10
£13,171 8 8
5,552 13 2
1,009 7 7
250 O O
To labour cost
Tribute of ore
Redruth Railway Co.
On account of coals imported
Merchants' bills, &c. .
Profit
In hand end October, 1863
Balance.
•
1,600 0 O
•
•
3,295 12
7
•
Deduct dividend, Ios. per share, 17th February, 1864
In hand
-I1,707 13 4
1,463 15 4
100 7 8
1,564 3 O
1,450 o o
£ 114 3 0
"Herodsfoot Mine and Liskeard Lead Mines.-The lead-mining district in
the neighbourhood of Liskeard has of late years been one of considerable
economic importance. It is rather a scattered district, extending in the
* F. Burr, The Mining Review, 1835.
CHAP. IV.]
HERODSFOOT LEAD LODE.
433
Killas in a zone about eight miles long, from four miles east-north-east of
Liskeard, to about the same distance south-west of that town, flanking on the
south the Caradon Granite range, at a distance varying from two and a half to
five miles. The lodes which produce lead ore in this zone have an approxi-
mate bearing north and south, while the copper lodes to the north of Liskeard
course nearly east and west.'
""
The most ancient mine in this neighbourhood is Herodsfoot, which has
been worked above eighty years, and formerly resulted in large returns from
shallow workings in the valley. The present workings were commenced
nearly eighty-one years ago, but the mine gradually became poor, and some
of the workings had to be abandoned. The lode, both in a north and
south direction, encountered the "broken-or-slidy-ground," as it is called,
which is common to this district. This ground is remarkable; it seems as if
the whole had been disturbed, and broken up into a breccia of the nature
of "cross courses" or "slides," and the lodes are shattered and lost, although
occasionally rich pieces of ore are found. The conditions are similar to
those already described in relation to the lodes at Relistian and Herland.
In 1862 the prospects of the mine were very gloomy, and it was almost
determined to abandon her entirely, but eventually it was decided that
the exploration should be continued, and new workings were opened
up, south of the "broken ground." These new workings soon became rich
in silver-lead, and the Herodsfoot ore was amongst the most argentiferous
raised in the kingdom, some of it selling at £28 7s. 6d. a ton. In the old
mine the produce of silver was about 12 ozs. to the ton, and the ore of the new
workings frequently gave as much as 70 ozs. to the ton, but at the same time
there was a considerable falling off in the yield of lead.
Some of the levels worked were exceedingly rich in lead ore-sometimes
containing very little silver-at others being as argentiferous as the richest
lead ores of Devonshire. The Herodsfoot lode lies a few degrees west of
south, and its average value is from 8 to 9 cwts. of ore per fathom.
The only ends driving in the mine in 1863 were the five that were
extended south from the new shaft-the 70, 82, 106, 117, and 127 levels. The
106 and 117 were extended to 60 fathoms south of the new shaft, the other
three were only a little south of it. The 70, worked by two men, had a good
lode in the end; the 82 had also a rich lode, and was only one fathom
south of the shaft; in the 106-fathom end the lode divided into several
branches; a cross cut was driven to intersect them all, and the produce has
been estimated at about 15 cwts. per fathom. The lode in the 127 end has
been interfered with by the disturbed ground.
At the back of the 106, 117, and 127 fathom levels there were thirteen stopes
working; those at the back of 127 being on an exceptionally rich lode, one
worth some 2 or 3 tons to the fathom, the ore ground being from 2 to
3 feet wide. The lode on part of this stope is of large grain, not very rich
for silver, but a little farther north, it suddenly changes to a very fine-
grained argentiferous ore.
Up to 1862, the produce of lead ore from this mine was 9,648 tons,
which sold for £146,992 13s. id.
Wheal Mary Ann mine, in the parish of Menheniot, is on the same lodes
F F
434
[BOOK II.
THE FORMATION OF DEPOSITS.
as Wheal Trelawney and Trehane. In the northern part of the sett adjoining
the Trelawney boundary the ore made quite up to the surface. Southwards
the lode is cut off by the disturbed ground. The 160-fathom level commu-
nicates from shaft to shaft, and south of Clyma's shaft is extended about 76
fathoms. For the whole of this distance the lode has been productive of
lead ore, averaging from 5 to 7 cwts. per fathom, but at some points it reached
as high as 26 cwts., while at others it fell so low as from 2 to 3 cwts. The
details of the workings in this division of the mine need not detain us. The
lode in Wheal Mary Ann, and in Trelawney, is a large and stony one, con-
taining a good deal of fluor-spar and carbonate of lime, with capels generally
on both sides.
One of the most remarkable features in Wheal Mary Ann is the
Fig. 72.
great run "of slidy ground" which cuts off the
lode southward. The first effect of this dislo-
cated ground is that the lode is thrown to the
right with a bearing west 45° south (Fig. 72).
After the slidy ground has been intersected, the
lode has not again been seen, although the 110-
fathom level has been driven considerably south,
and east and west. Some branches have been
more than once met with, but they always soon
disappeared. This mine made all its later re-
turns from below the 200 fathoms, and was even-
tually abandoned on account of the cost. The
returns from these three mines in the ten years
before their close were as follows:
Herodsfoot.
Tons. cwts.
547 9
Wheal Mary Ann.
Tons. cwts.
Trelawney.
Tons. cwts.
879
1,272
1866
1867
540
2
830
1,048 13
6 ·
6
5
1868
582
6
1,139 16
756
3
1869
537
6
1,005 18
•
574 13
1870
508 15
1871
•
•
473
941 16
1,047 18
369 14
362
8
1872
460
1,254 O
1873
321
I
759 15
1874
•
376
9
538
O
1875
2
331 I .
After a repose a fresh start has been made in Mary Ann and Trelawney
with every prospect of success. Herodsfoot continued to produce as follows :—
Tons. cwts.
1876
286 16
•
1877
322 15
1878.
1879 .
•
Tons. cwts.
307 15
256 6
Tons. cwts.
1880
1881
•
•
451
2
•
435
O
The North Herodsfoot produced 22 tons 16 cwts., and in addition we have
now East and West Herodsfoot, East Hony, and Hony and Trelawney
United. The striking peculiarity of this lead-producing district is, that all
the productive mines are confined to one mass of rising ground, while similar
elevations to the east and west are unproductive.
The lode at Wheal Mary Ann has been well described by Dr. C.
Le Neve Foster, in a paper which he read before the Geological Society
CHAP. IV.]
WHEAL MARY ANN LODES.
435
of Cornwall,* and he describes some peculiarities well deserving especial
notice.
Fig. 73 shows a characteristic section of the lode as seen in the 250-
fathom level. We have first of all the two walls of Killas, then proceeding
inwards from each wall the cab-a sort of chalcedony-then ordinary vitreous
crystallised quartz, next galena, and finally chalybite or spathose iron.
Fig. 74 shows another section of a similar lode, the only difference
being that the "cab" on the footwall contains fragments of Killas.
Dr. Le Neve Foster, from the examination of these sections, deduces the
following history of the lodes :—
First, the formation of a fissure, probably accompanied by a shifting of
the strata. A succession of open spaces were left, and some parts were more
or less filled up by fragments which fell from the walls.
Secondly, deposition of the cab, which more or less filled up the fissure
Fig. 73.
Lodes at Wheal Mary Ann.
Fig. 74.
and cemented any fragments of the walls into a breccia. As would naturally
be supposed, this breccia occurs chiefly on the footwall.
Thirdly, re-opening of the fissure. The new line of fracture sometimes
occurred in the middle of the filling up of cab, sometimes it cut across it, and
then followed one of the walls of the original fissure; pieces of the walls and
of the previously-formed cab lode fell in, and then quartz, galena, chalybite,
and calc-spar were deposited successively in the open spaces.
Dolcoath Mine, Camborne.—Mr. Josiah Thomas, in describing Dolcoath,
remarks, “that although all the lodes which have been extensively worked
have produced large quantities of copper ore, yet only the main lode and those
lodes to the south immediately connected with it, and which fall into it,
have been rich for tin. The other lodes, which are smaller, or not connected
with the main lode, have nowhere, so far as explored, produced tin enough
to be profitably worked. The total length of levels driven on the lodes,
together with cross cuts, is about 50 miles in addition to 12 miles of shafts
* "On the Lode at Wheal Mary Ann, Menheniot." By C. Le Neve Foster, B.A., D.Sc., F.G.S.
("Transactions of the Royal Geological Society of Cornwall," vol. ix. part i. 1875.)
F F 2
436
[BOOK II.
THE FORMATION OF DEPOSITS.
and winzes." The usual size of the ends driven is 8 feet high by 6 feet
wide. The ground is very hard, and has mostly to be broken by blasting.
The cost is upwards of £20 per fathom.
Mr. Thomas, in the year 1870, said: "The mine has been producing
about 87 tons of black tin (or tin ore) per month, or 1,050 tons per year; in
order to obtain which, we raise and stamp about 1,000 tons per week, or
52,000 tons per year; so that the average produce of our tin stuff, as raised
from underground, is as near as can be 2 per cent. of tin ore; or, in other
words, only one part in 50 (except a little arsenic) is of any value, the other
49 parts being worthless.
"To work so deep a mine (nearly 2,000 feet from surface) and to raise so
large a quantity of tin, from so hard a rock, is necessarily attended with great
labour and expense. There are two steam-engines, respectively of 85 and
60 inch cylinder, employed in pumping water from the mine, and three
steam-whims drawing stuff (but of these one only works occasionally).
There are also two steam-engines employed in stamping, and one in working
the 'Man-Engine' for lowering and raising the miners.
"Our stuff is drawn to the surface by kibbles and wire ropes. The kibble
will contain one ton of stuff, and the ropes are made of steel wire 31 inches
in circumference. One steam-whim draws from two shafts at the same time,
there being one kibble in each shaft; so that whilst the empty kibble is being
sent down in one shaft, the full kibble is being drawn to the surface in the
other. In ordinary working we can easily draw with one steam-whim from
the bottom of the mine 6 tons per hour.
"On being drawn to the surface the rocks are 'spalled' or broken into
small pieces of two or three inches in diameter, to prepare it for being
stamped. The large rocks are broken into smaller pieces by men, but the
'spalling' is principally done by girls, with small steel sledges, at a cost of
about 41d. per ton.
"The particles of tin being small it is necessary to reduce the stuff to a
very fine powder. This is done by two steam stamps, one having 120 heads
and the other 60 heads. In the winter there are 20 heads worked by
water power.
By means of these stamps the stuff is reduced so that the
particles will pass through a grating with 150 holes to the square inch, or if
the particles of tin are large a rougher grate is used. The ore is dressed
entirely by 'buddle' and 'kieve.' The centre cone buddle' is the one
generally adopted, the one used at Dolcoath being from 16 to 22 feet in
diameter, and the diameter of the central cone being from 5 to 8 feet,
according to the nature of the stuff to be dressed. On the top of the centre
is a funnel with an iron plate attached for distributing the stuff equally over
the centre, and also three or four arms for brooms or sweeps, which, together
with the plate and the funnel, are made to revolve by machinery driven by
a water-wheel, whilst around the buddle is a trench filled with water into
which, whilst the buddle is being worked, the tails or worthless parts of the
stuff are washed away after being separated from the tin buddling. The
stirring' and 'packing' in the kieves are also performed by water power.
"The ore is afterwards calcined, to separate the arsenic which is usually
combined with tin ore. For this purpose Brunton's calciners are generally
<
CHAP. IV.]
DIFFERENT STATES OF MAGNETISM.
437
used. The arsenic is driven off in fumes and deposited in flues; the tin is
left behind, and again dressed in buddles and kieves. When it has thus
been freed from waste it is ready for the market, and the tin ores of
Dolcoath produce nearly 70 per cent. of metal."
Already some remarks have been made on the supposed influence of the
direction or bearing of the lode on the production of metallic ores. If there
is any sufficient confirmation of this, it at once establishes a close relation
between the deposition of ores and terrestrial magnetism. We know that
iron, nickel, and a few other metals are what is called magnetic; that is,
they place themselves at right angles to the direction of an electric current,
while bismuth, and most other substances, have a tendency to arrange them-
selves across the line of magnetic force. The consequence of this is the
tendency of a magnetised bar of iron to point to the North Pole; or, in other
words, to arrange itself north and south. On account of this property we
employ a magnetic-needle in our surveying instruments, to guide us in the
true direction of the lode upon which excavations are being made, and to
secure correct results in our surveying operations.
Dr. Faraday called one set of metals—those which are magnetic, as iron
is-magnetic bodies; and those which exhibit a tendency to arrange their
long axes at right angles to the direction taken by a bar of iron, dia-
magnetic. This will be better understood by a diagram:-
N
N
I
S
N
B
S
S
N
S
N and S represent the poles of a horse-
shoe magnet (Fig. 75). If a piece of iron is
hung up between the poles, the active force
compels the bar to arrange itself so as to
join the two poles as I does, the North
Pole N being opposite the pole S, and the
S pole being opposite the N pole of the
magnet. If, on the contrary, a bar of bis-
muth is so suspended, it arranges itself at
right angles to the direction of the mag-
netic force, as shown at B (Fig. 76). The
magnetic force is supposed to pass through
bodies thus constituted, and they are called
dia-magnetic, the prefix dia having the same meaning as in diameter. It
has been already stated that the sun establishes an electric disturbance, from
every point, on which its rays fall, and this disturbance, or current, traverses
the Earth from the east to the west. A magnet is compelled to dispose
itself so that one pole points northward, and the other to the south, or across
the line of the solar electric current. The diamagnetic bodies naturally
tend to take a direction at some angle, nearly agreeing with that of the
electric flow.
Fig. 75.
Fig. 76.
This brief explanation of a very refined experiment is given, for the
purpose of explaining the principle, upon which it may be supposed, that
direction has something to do with the deposition of mineral riches in the
veins, or cracks which take a certain bearing, in relation to the magnetic
meridian.
Captain Charles Thomas, who was for many years the managing agent
438
[BOOK II.
THE FORMATION OF DEPOSITS.
of Dolcoath mine, in some lectures delivered by him at Camborne, and sub-
sequently published, directed the attention of his hearers-chiefly young
miners—amongst other important matters, to "the direction or bearing of
the lode in your sett." His words are as follows :—
,, *
"This is of greater importance than is generally supposed. Where the
direction is wrong, whatever other favourable indications may be present,
I have never known a profitable mine. The best direction for different
metals varies very greatly. In the following remarks I take the present
magnetic line, which is about 249 west of true north.†
“Tin lodes varying from 30° north of east to 30° south of east (magnetic),
a range of 60°, have been found profitable for working. Copper lodes with
a similar range of 60°, but varying from 10° north to 50° south of east, have
been found profitably productive. Lodes varying from 5° north to 25° south
Old Dolcoath Gross Course
60
Sorth Entral Lode
52
22
12
Main
Lode
D
160
160
60
125
Little North Lode
Valley Counter
20
115
Lode
125
125
160
Caunter
Lode
49 ·
40
70
REFERENCES.
Rich parts of the Lode thus...
Orey
Poor
Do
Do
Do
Do
Gosston Cross Course
Fig. 77.-Productive Parts of Lodes at Dolcoath.
In the
of east have, however, yielded the greatest quantity of copper ores.
lodes whose direction is from 25° to 50° south of east very rich ores are
found, but not in very great quantities. In lodes bearing more than 10°
north of east (or 34° north of true east) the ores are generally very poor.
'The best direction for lead lodes is from 10° west of north to about 40°
east of north. I believe the above to be a statement of facts as found
* "Remarks on the Geology of Cornwall and Devon in connection with the Deposits of Metallic
Ores, and on the Bearings of Productive Lodes." By Captain Charles Thomas, of Dolcoath Mine.
Camborne: 1859.
†This was in 1859. The magnetic elements for 1883, at the Royal Observatory at Greenwich, are--
Declination (or variation of the compass)
18° 15' west.
Inclination (or dip of the needle)
•
Horizontal force (measured in British units)
Vertical force
Total force
""
""
""
•
•
67° 32'
3.92
9.48
10.26
To find the true north in or near London by means of a magnetic-needle the compass must be so placed
that the north end of the needle points about 18° 15' west. The north and south points of the dial will
then be in the true meridian nearly. The magnetic variation along a line passing from the south of
Dorsetshire to Whitby will be 19° 12' west, and a line passing from the river Tamar to Durham will be
20° 12' west.
CHAP. IV.]
THE MINERA MINES.
439
existing in the mines of Cornwall and Devon. The exceptions are exceed-
ingly rare, and when they occur the cause can be ascertained. The St. Just
district, I think, affords the only apparent exception to the rule, and some of
the deposits of copper ore even there may be satisfactorily accounted for in
accordance with this rule. I have found in numberless instances a rich
course of copper ore while the direction of the lode was south of east, due
east, or 5° north of east; but a turn in the lode taking place of 5° or 7°
farther north, the lode would not pay for working." The diagram, Fig. 77,
showing the productive parts of the lode for copper ore in Dolcoath mine,
illustrates the hypothesis of Captain Charles Thomas.
The Minera mines-Denbighshire-have been celebrated since the com-
mencement of the eighteenth century for their remarkable production of lead
ores, and they are yet amongst the first of the British lead mines, for large
returns of ore. In 1881 they produced 1,250 tons of lead ore, containing
8,120 ounces of silver of the value of £12,870, and 5,468 tons of zinc ore of
the value of £21,050.* The district about them is equally remarkable, for
within a radius of five miles from the mines, we find most of the common
British minerals of commercial value, except tin ore, and the representatives
of every strata occurring between the Lias and the Cambrian-a portion of
the English series of stratified rocks, of far greater interest and value, in an
economic sense, than all the others.
Disregarding the Roman workings of these lead deposits, and the subse-
quent workings which are alleged to have occurred at various periods ante-
cedent to the year 1700, a brief summary only is given of the more recent
operations. About the year 1710 the first regular and systematic mining
operations seem to have been commenced at Minera, beginning in that portion
of the present sett then known as the West End mines. Here the near
proximity of the ore-bearing strata to the surface, and the outcropping of the
lower measures, appealed at once to the miner, and extensive workings were
established on several veins, and split portions of the main lodes, as well as
in the flats which abound in those particular strata. The gradual extension
of these operations eastward, following the dip of the measures, induced
other parties to make a trial of the still more eastern ground, and for many
years the results were profitable to both companies. From 1720 to 1824
(when the different leases terminated) the fortunes of both setts were
chequered, as they fell into various hands; yet the workings seem always to
have been attended with a full measure of success. About 1816 the West
End mines finally stopped, not so much, however, from poverty as from the
enormous influx of water, which frequently flooded the mines and entirely
prevented the carrying on of regular operations; and in 1824 the suspension
of the East End mines followed from the same causes, the "bottoms being
still rich and productive.
""
There are two principal veins at Minera, the Old vein and the Red vein,
both coursing almost the entire length of the property, which is about two
miles long and half a mile at the extreme breadth. The Old vein was for a
considerable period believed to be the only vein in the East End mines.
*"Mining and Smelting Magazine," vol. ii.
440
[BOOK II.
THE FORMATION OF DEPOSITS.
This vein is really a true fault, which has become filled with mixed
mineral matter. At Andrew's shaft, about the centre of the property, it
has a down-throw of 410 feet to the north, the Millstone Grit and shales being
to the one side of the vein and the Limestones on the other. The throw of
the fault varies, rapidly decreasing as it goes westward, while going eastward,
for some distance at least, it seems to remain somewhat constant, attaining a
maximum near Taylor's engine-shaft.
This vein, being a fault fissure, the deposits of ore, as in all such cases,
are very irregular, and exceedingly "bunchy," sometimes swelling out into
immense masses of ore, or gangue, and at others becoming quite poor and
nipped up. The vein is so small and poor at Andrew's shaft, that in driving
the deep adit level on the vein, for scores of fathoms, it required the keenest
and most practised eye, to discover that a vein existed at all, and again in the
short distance of two or three fathoms it suddenly opened out to a large size,
producing a rich bunch of ore. The Old vein is also subject to many sudden
changes of this kind.
The general uncertainty of the occurrence of these runs of ore has led
to the adoption of a regular system, of cross-cutting the lode, at very short
intervals, from which excellent results have been obtained. Very frequently,
after following a branch of ore worth £60 or £80 per fathom, which, with
its accompanying veinstone, is enclosed between two faces, resembling the
regular walls of a lode, if a cross cut be put out, it will be found to pass for two
or three fathoms through a confused mass, more or less brecciated—of Lime-
stone, hard shale, and gangue-when another equally valuable branch of ore
will probably be found, also enclosed between regular faces. A continuation
of the cross level has even at times discovered another and third branch of
lead ore under similar circumstances. If continued, the cross cut would ulti-
mately reach the hard black shales, showing the limit of the veins, for such is
the nature of the country, north of the Old vein in the East End mines.
The dip of this vein is about north-east (true), the angle averaging 80°. It
therefore courses about south-east and north-west. Previous to splitting up,
as it does in the West End mines, it takes a slight curve to the west, coursing
here about north-west by west (true). Towards the Grand Turk and Busy
Bee shafts it bifurcates, and branches run off, which may be considered.
true veins; indeed, it is here that, for the first time, anything of a character
analogous to the regular lodes of Cornwall is found. These offshoots
course regularly, have distinct walls enclosed by true Limestone country, and
they have in many instances been remarkably productive. Although this old
vein may, in a mining sense, be considered as a lode, yet its real character
is an ordinary fault containing mineral matter. As the fault caused by this
old vein continues west, it decreases very considerably in its throw. The
Limestone here is the surface rock on both walls of the veins. The thick-
ness of the Limestone varies, however, materially, and frequently most
irregularly, being seemingly to a great extent determined by the vein, which
may traverse it at the point of observation, every vein at Minera having some
throw, or dislocating effect, on the strata. In this respect we trace an analogy
between the Minera veins of Denbighshire and those of Alston Moor.
Farther west the veins undergo another change; they become themselves
CHAP. IV.]
COAL MEASURES AND LEAD LÒDES.
441
much poorer, but act as feeders to numerous "Flats," "Pipes," or similar
irregular deposits. Under these conditions some remarkably fine masses
of ore have been found, and the enormous cavern-like excavations, in
Maes-y-ffynnon and Llyn Ddu, sufficiently attest the truth of the statements
which have been handed down to us in respect to them. In this part of the
mine the ground is a hard and compact white Limestone, and the ores'
deposits are almost totally unaccompanied by veinstone of any kind. The
veins here are very open, and form channels for the passage of the immense
quantities of mud, sand, and water which in rainy seasons flow through them.
There is a marked difference in the character of the eastern and western
portions of the Old vein. Near the Meadow, or extreme eastern shafts in the
upper levels, this vein occurs in black shales and Slates belonging to the
Lower Coal and Millstone Grit series, and is usually very poor; deeper it
intersects the Carboniferous Limestone, and becomes to some extent produc-
tive, but instead of lead deposits we find the lode filled with large quantities
of brown blende. This ore is intermixed with pulverulent and massive
quartz, and contains many large stones of galena. Farther westward,
between Taylor's shaft and Ellerton's shaft, the Old vein becomes largely
productive. The West End mines, the Old vein, as well as the cross and
caunter lodes, which are found in this part of the Minera mines, have some
shale, a little blende, and much calc-spar, as their characteristic mineral;
quartz does not occur in any quantity, and but little lead is found.
Besides the Old vein there is another lode of extreme productiveness
which in the East End mines is called "North vein," and in the West End
mines "Red vein."
Red vein." The North vein, in some of the orey portions, is
extremely cavernous. At Meadow Shaft there is a powerful deposit called the
"Marion String," crossing from the Old to the North vein. Westward of
this, nothing has been seen of the lode for 800 yards. Passing the whole of
the ground lying between Taylor's and Andrew's shafts, which on the Old
vein was so valuable, we reach the point where the North vein is seen
for the first time; here it was but moderately productive, but being followed
westward yielded large returns of ore. Some of the bunches of galena were
of enormous size, so that it has not been rare to see parcels of vein stuff,
60 tons in weight, drawn from these workings, containing not more than 15
per cent. of foreign matter. This deposit of ore extended as high as the 100-
yard level, and has been quite as rich in its upper as in its lower zones.
In the neighbourhood of Andrew's shaft we observe the "parallelism of
veins" distinctly exemplified in the large measure of metalliferous wealth
stored up in the same belt of ground.
At Maes-y-ffynnon we find the lode absolutely poor, a mere fissure in the
strata, and free from even a moderate quantity of veinstone or gangue. The
cheeks of the vein " here consist of the bottom measures of the Limestone,
with some Millstone Grit, the whole resting at the depth of 100 yards upon
the Silurian Rocks.
It is a point of interest to find the Brymbo main coal approaching the
metalliferous lodes of Minera. It would appear that the North vein ulti-
mately attains, approximately, the same amount of dislocation as the Old vein
has at this point, the Old vein diminishing to a heave of small importance
442
[BOOK II.
THE FORMATION OF DEPOSITS.
when fairly in the Coal Measures. This point of ultimate change is
about two miles from Taylor's shaft. Here the two faults are uncertain in
their character, but their existence admits of no doubt. They have a combined
throw of about 120 yards, and form a channel of faulty ground which divides
the Brymbo and the Ruabon coal field, and which is known to course from
Minera through Pentre-Bychan. At this point the Brymbo main coal-a little
to the east of Pentre-Bychan-is probably at least 200 yards deep, while
on the other side of the fault it does not, in a corresponding position, exceed
80 yards from the surface.
To the north-east of the North vein the ground is greatly disturbed,
the edges of the strata, impinging against the vein, being broken and dis-
turbed in a high degree. No regular coal has been noticed, only small
lumps of carbonaceous mineral, but the strata, composed of shales and thin
Sandstones intermixed, the former preponderating, belong to the true Coal
series, the fossil flora of the series in this district, having probably all of its
genera represented. The shales give evidence of a sliding action, and show
the peculiar polished faces, slickensides.
The rich ore-bearing vein of Minera has been stated to be a true fault.
It forms the northern throw of a faulty channel of ground separating the
Coal and Millstone Grit Measures from the Mountain Limestone. At the
extreme east, near the "Meadow Shaft," as it is called, the lode enters the
Lower Coal Measures, where it appears to be split into several branches. These
are found in black shales, and contain large and beautiful iridescent cubes of
galena, associated with quartz, which frequently leave pseudomorphous
impressions of their crystals. The deepest point in the Minera is Roy's
shaft, 315 yards below the surface. In the year 1876 the Darlington rock-
boring machinery, and the blasting of the shot-holes by electricity, were
introduced, since which the power drills continue to do good work with very
beneficial results as regards increased speed of driving and economy in
working the mine.*
The following statement of the financial position of the Minera mines,
as an example of successful mining, will be of interest :—
The capital of the undertaking is
The produce raised and sold from 1850 to end of 1882 consists of 108,369
tons 3 cwt. of lead ore and 63,784 tons 19 cwt. of blende, which
realised together
•
The payments include-
Promoters for leases of mines.
Freehold landed property
Royalties
Mine costs
Dividends.
Reserve Fund
Cash in hand
£615,916 5 0
£
s. d.
45,000 o O
1,692,324 14 2
£1,737,324 14 2
£7,500 o o
712 18 1
8,212 18
I
£147,869 o 10
954,941 8 3
1,102,810 9 I
8,740 7 8
1,644 14 4
626,301 7 0
1,729,111 16 1
£1,737,324 14 2
* "Mineral and Geological Sketch of the Minera Mining Field, Denbighshire, North Wales." By
George Darlington. ("Mining and Smelting Magazine," vol. ii. 1842.)
CHAP. IV.]
LEAD MINES OF DENBIGHSHIRE.
443
Within the limits of the Denbighshire district the following setts have
been wrought-Bodidris, Bryn Derwyn, Cefn-y-gist, Denbighshire Consols,
Dyffryn Mid, Lady Ann, Lead Era, Minera Consols, Minera West, Minera
Mountain, Nant Uchaf, Pont-Du, Waenlas, Park, Pool Park, and Union and
Boundary.
These mines have not been very productive; the produce of lead and zinc
ores in 1881 being as follows :—
•
Lead Ore.
Tons. cwts. qrs.
Bodidris.
Bryn Derwyn
Cefn-y-gist
Denbighshire Consols
31
8
IO
4
O
6 IO
о
100
12 O
·
Minera Consols
7
I
0
Minera Mountain
|
Minera West
O IO
O
Pont-Du
6
O
Union and Boundary
Park
12
ΙΟ
Pool Park
•
Zinc Ore.
Tons. cwts. qrs.
350
•
16 0 0
·
100
O
•
15
о
A brief description of some of these mines, where they present any
peculiar character, must be given.
The Park mines have been wrought through an extended period with very
variable success. They are situated west-south-west of Minera. The veins
worked in those mines are entirely distinct from those in Minera with
one exception. The Ragman vein is a caunter to the Minera lodes, and tra-
verses the eastern portion of that sett. The surface of the Park mine is at an
elevation of nearly 500 feet above the level of the railway at Minera, which
corresponds with the back of the Old vein. The Park mine has been chiefly
worked upon one vein, which courses north-west by west, and underlies
pretty regularly at about 15° from the perpendicular, being occasionally
broken by the shale beds. There are some other small veins in the Park
sett which appear to be branches of the main lode. The flats and dry feeder
veins of Minera have been expected to run into the Park mine, but they have
not been determined. The veins in the Park sett are chiefly composed of
lead ore, calamine, calcareous spar, quartz, blende, and clay. The carbonate
of zinc, which has been occasionally found, appears to take the place of
the blende, which is found so plentifully in Minera.
Pool Park mine appears to have been worked upon a vein which is inti-
mately related to that in the Park mines. The ore occurs in irregular masses,
and has sometimes been found in pipe or in pillar deposits, of great purity
and richness.
Minera Union is on the north-western outcrop of the Mountain Limestone,
the strata having an average thickness of about 200 feet. The veins in this
mine resemble in most respects the mineralogical character of the central
portion of Minera. The veins have been usually productive, and the measures
through them are regular and even in their character; they crop out in the
eastern end of Central Minera.
Central Minera lies to the westward of the Union mine, close by the
"Great Denbighshire Fault." The veins are very irregular, but a few fine
bunches of lead ore have been found in them. The Ragman vein is here proved
444
[BOOK II.
THE FORMATION OF DEPOSITS.
to be a caunter to every vein in the entire district, coursing almost north
and south. This great vein is the most marked, and the poorest, in the dis-
trict. It cuts into this sett, but, unless in some of its offshoots, it has never
been productive. The Ragman is traceable for two miles, as a most regular
lode. Its strike, underlie, thickness, and mineral contents are all remark-
ably uniform. Its contents are chiefly sand, clay, and matter eroded from
the surrounding rock, and carried by water into this fissure, through the
numerous cracks and cavernous watercourses which exist in the Mountain
Limestone on its western outcrop. There is so great an analogy between the
Ragman and the great Flintshire fault, through which the stream discharged
at Holywell flows, that they may be referred to the same set of geological
phenomena. The causes which have led to the enrichment of the Minera
lodes, and those in the neighbouring mines, are not satisfactorily determined.
A change of underlie, or branches, or feeders flowing in from the south,
often produces bunches of lead ore. Large quantities of lead are always asso-
ciated with certain well-marked strata, and always follow them in their
eastern dip. The occurrence of black shale and pulverulent quartz are reliable
indications of wealth. In some places calamine in the upper part of the lode
is a satisfactory indication of lead ore in depth, and blende under similar
circumstances is, say some authorities, "an invariable guide to wealth.”
Most of the veins in this district are thought to be contemporaneous.
The same movement without doubt produced all the parallel fissures. This
disturbance occurred subsequent to the deposition of the coal strata, for the
Minera veins, which are co-existent with the others, break through the
Coal Measures as faults.
Anglesea Mines.-Parys Mountain-which is a portion of Trysclwyn—
derives its name from a Robert Parys, who was chamberlain of North Wales
in the reign of Henry IV. (Pennant, in his "Tours in Wales," says doubtingly
of this, "There was another of the same name in the reign of Edward III.")
From what has already been stated, it will be evident that this district was
worked for copper in the days of the Romans, if not by the Britons. In 1762
Alexander Frazier was in Anglesea seeking for mines, Sir Nicholas Bayley
gave him so glowing an account of Parys Mountain that he was induced
to make a trial. Ore was discovered, but before any quantity could be
raised the mines were flooded, and their means for removing water were
so inefficient that the works were suspended. In 1764 Messrs. Roe and
Company of Macclesfield applied to Sir Nicholas Bayley for a lease of
Penrhyn Du in Carnarvonshire, which was granted only on the condition
that they leased a portion of Parys Mountain and made a fair trial of the
mine. They commenced operations, and ore was obtained, but the cost was
excessive. These adventurers were great losers, and they resolved to
abandon the mine. Orders were given to their agent, but he resolved on a
final attempt at discovery. He divided his men into ten companies, and
directed them to sink shafts in several places. Near a spot, called the
Golden Venture, led, it is said, by a spring to believe that a body of mineral
must exist there, they sunk a shaft. On the 2nd of March, 1768, they
discovered the mass of ore, which has been worked continuously since that
time. Pennant informs us that "soon after this discovery the Rev. Edward
CHAP. IV.]
PARYS MOUNTAIN AND MONA MINES.
445
Hughes, owner of part of the mountain in right of his wife, Mary Lewis, of
Llys Dulas, began to work, so that the whole treasure is the property of
Sir Nicholas Bayley* and himself.
Pennant gives an interesting but not very exact account of the Parys
mine. "The body of copper," he says, "is of unknown extent. Several
years ago” (written 1810) "the thickness was ascertained by driving a level
under it, and it was found to be in some places 24 yards.
The ore
is mostly of the kind called by Cronstedt Pyrites capri flavo viridescens
(yellow copper ore, or copper pyrites, some of it being the iridescent
variety called peacock copper), and contains vast quantities of sulphur.
. . There are other species of copper ore found here. Of late a vein of
Pyrites cupri griscus of Cronstedt (grey copper ore), about 7 yards wide,
has been discovered near the west end of the mountain; some is of an
iron grey, some quite black; the first contains 16 lbs. of copper per cwt.,
the latter 40 lbs. An ore has been lately found in form of loose earth, of a
dark purplish colour, and the best of it has produced more than 8 in
20.
Some years ago above 30 lbs. of native copper was found in driving
a level through a turbery (a turf field); some was in form of moss, some
in very thin leaves. The ore is quarried out of the bed in vast masses, it is
broken into small pieces, and the purest part is sold raw, at the rate of
about £3 to £6 per ton, or sent to the smelting-houses of the respective
companies to be melted. Mr. Hughes has great furnaces of his own at
Ravenhead, near Liverpool, and at Swansea, in South Wales. An idea of
the wealth of these mines may be formed by considering that the Maccles-
field Company have had at once 14,000 tons of ore upon bank, and Mr.
Hughes 30,000 tons. . . . The ore is not got in the common manner of
mining, but is cut out of the bed in the same manner as stone is out of a
quarry. A hollow is formed in the solid ore open to day, and extends
about 100 yards in length, about 40 yards in breadth, and 24 yards in
depth. The ends are at present undermined, but supported by vast pillars
and magnificent arches, all metallic, and these caverns meander far under-
ground (Fig. 78). These soon disappear, and thousands of tons of ore
begotten from both the columns and roofs. The sides of this vast hollow
are mostly perpendicular, and access to the bottom is only to be had by
small steps cut in the ore; and the curious visitor must trust to them
and a rope till he reaches some ladders which will conduct him the rest of
the descent. On the edge of the chasms are wooden platforms which project
far, and on them are windlasses by which the workmen are lowered to
transact their business on the face of the precipice. There suspended they
work in mid-air, pick a small space for a footing, cut out the ore in large
masses, and tumble it to the bottom with vast noise. In such situation they
form caverns (in which the men rest during explosion of gunpowder in
blasting), and there appear safely lodged, till the rope is lowered to convey
them up again. Much of the ore is blasted with gunpowder, eight tons of
which, I am informed, is annually used for the purpose."
It is desirable that a careful account should be given of all the known
* Afterwards Earl of Uxbridge, now Marquis of Anglesea.

446
[BOOK II.
THE FORMATION OF DEPOSITS.
conditions under which this extraordinary deposit occurs. The drawing
given on page 452 (Fig. 83) faithfully represents the Clay Shaft lode, and
four other important mineral veins, as they approach the surface, and
enter the Great Open Cast: giving a correct idea of the conditions of these
deposits. The greyish-blue Clay-Slates immediately beneath become more
and more quartzose as they approach it; certain portions transfused with
silicious matter, displaying a flinty character, whilst other parts are made
up of Slate and quartz in distinct and separate lamina; several large and
exclusively silicious beds of schistose structure enclose, here and there,
bodies of massive quartz, and broad bands of greyish hornstone occur at
intervals. The Slate directly
overlying the ore is generally
brownish, but-exhibiting vari-
ous colours within short dis-
tances-it passes gradually into
a normal blue. Many beds are
sprinkled and veined with sili-
cious substances, but these
rarely accompany the thick
conformable layers of metalli-
ferous quartz which have been
largely worked in the northern
parts of the mines.
South of the great metalli-
ferous deposit, where little or
nothing of much value has yet
been found, the planes of
cleavage, maintaining a toler-
able regularity, bear nearly east
and west. In other parts of the
district, however, their direc-
tions are less uniform; for the
average of their many large
flexures in the Mona mine to-
wards the north-east is 12° to
30° south of east to north of
west, near the boundary of the
mines they range about east and
west, and in the Parys works, on the north-west, some 15° to 25° north of
east to south of west. Moreover, the wide floor of copper-bearing quartz,
worked to a greater or less extent in various parts of both mines-as in the
Carreg-y-doll lode-is subject to like flexures; and the smaller metalli-
ferous beds, severally known as the Clay Shaft lode and the Charlotte lode in
the east, as the North Discovery lode towards the west, and as the Black
Rock lode throughout, also conform to the undulations in their respective
neighbourhoods. The relations between the great metalliferous deposit and
the rocks adjoining it are not now very readily discerned; its general
direction, however, is some 12° to 15° north of east to south of west, and
Fig. 78.-Caverns worked from the Open Cast.
MBAUNY
S
!
CHAP. IV.]
SECTION OF STRATA, PARYS MINE.
447
its dip, like the dip of other productive beds of quartz and the cleavage-
planes of the neighbouring Slate, ranges from 50° to 84°, and averages,
perhaps, 65° towards the north. The formation is intersected by joints of
two series, which, differing both from the copper-yielding beds and from the
cross veins (flucans) in direction, bear 25° to 35° west of north to east of
south, and 30° to 40° north of east to south of west respectively. Two
cross veins traverse the district, namely, the eastern, or Carreg-y-doll,
which ranges some 5° to 15° east of north to west of south, and the great,
or western, cross course which takes a nearly meridional bearing. Both
these cross veins heave the smaller productive beds they encounter towards
the left hand, and to the side of the greater angle, the Carreg-y-doll cross
course displacing the Charlotte lode but slightly, the Carreg-y-doll lode
about 12, and the Black Rock lode nearly 8 fathoms; whilst the western
cross course dislocates the Carreg-y-doll lode as much as 30 fathoms. Both
cut through the great metalliferous deposit also, but the extent of any heaves
Cherty Rock
herty-
Rocks
cupreous
straya
Great Open Cast
Clay Slaté
Unproductivé
5 4
3
90 /in Level
1. //
2
Fig. 79.-Parys Mine-Section across Strata.*
they may have occasioned is concealed by the rubbish which now covers
the sides of the openings wherein it was formerly wrought.
The North Discovery lode varies from about 2 to 8 feet, the Carreg-
y-doll lode from 1 fathom to nearly 10 fathoms in width; both enclose
conformable masses of Slate (horses), and consist in great measure of quartz,
quartzose Slate, chlorite, and disintegrated felspar, mixed, however, with
earthy brown iron ore as well as with smaller quantities of native copper,
earthy black copper ore, the sulphide of lead, and other minerals near the
surface, with yellow copper ore and specular iron at greater depths, and with
larger or smaller proportions of iron pyrites throughout.
•
The great metalliferous deposit appears not only to have occupied the
whole space between the Clay Shaft lode and Black Rock lode for a
considerable distance, but also to have extended some way north of one and
south of the other.
It has been wrought open to the day for about 90 fathoms on the line of
*For this and the two following woodcuts we are indebted to "A Treatise on Metalliferous Minerals
and Mining," by D. C. Davies, F.G.S.
N
448
[BOOK II.
THE FORMATION OF DEPOSITS.
its strike and more than 140 fathoms in extreme width in the hillside open
cast, and 210 fathoms on the line of its strike and 90 fathoms in extreme
width in the great open cast, to a depth of 18 fathoms and for an area of
5°331 acres in the former, and to a depth of 23 fathoms and for an area of
12.131 acres in the latter, and to greater depths for short distances in both.
The open casts are separated by a body of veinstone, varying from 10 to
50 fathoms in thickness, whence small quantities of copper ore are still
extracted.
Some idea may be formed of the value of these mines in their earlier
workings from the following figures:—
In 1778 both mines did not exceed 1,200 tons copper.
,, 1784
""
,, 1785
,, 1798
""
""
", 1799
""
""
3,000
""
""
2,300
""
""
""
1,700
1,900
""
""
The depths of these mines in several parts are-Middle lode, 150 fathoms;
Carreg-y-doll, 124 fathoms; Great Open Cast, 75 fathoms; North Discovery
lode, 150 fathoms.
The principal earthy ingredients-as in smaller productive beds on the
north—are quartz and quartzose slate, through which chlorite is thinly and
W
Shaft
Great
old Engine.
Shaft
Onen
Colone
Shaft
Cast
quis's
Shaft
Scale 1"-100yds
Fig. 80.-Section of Workings in Parys Mine.
rather unequally sprinkled; towards the east, however, and especially near
the (footwall) lower side, buff-coloured felspar is also abundant. Thin
fissile layers of blackish-blue slaty matter interlie the other constituents,
dividing them into ill-defined beds, parallel to the adjoining rocks. Shallow
parts of these mines have afforded much earthy brown iron ore (gossan),
containing nests of earthy black copper ore, and small cavities incrusted
with the carbonates of copper and the sulphide of lead. Beds, laminæ,
interlacing veins, isolated bodies, single crystals, and disseminated grains of
iron pyrites even yet abound in the quartzose and slaty portions of the mass.
Galena occurs in some and blende in other parts of the formation; and
occasionally the intractable association of both these with iron and copper
pyrites has been plentiful. Native copper, earthy black copper ore, vitreous
copper, and purple ore have been frequently obtained; the principal pro-
duce, however, has always been copper pyrites. Great quantities were, of
course, scattered through the earthy matrix; but during three months in
the year 1787 one party of workmen extracted "2,931 tons of good
CHAP. IV.]
SECTION OF WORKING IN PARYS MINE.
449
copper ore and only 92 tons of which was waste." In both the open
works several large masses of quartzose Slate (horses), interlaid by laminæ,
and intersected by thin veins of iron pyrites, have, by the removal of the
copper ore which surrounded them, been left standing as isolated crags.
(See Fig. 82.)
Between the two enormously rich portions (bunches) of the great metalli-
ferous deposit wrought in the "hill-side open cast," and the "great open
cast" respectively, a body of comparatively unproductive-yet slightly orey-
quartzose veinstone intervenes; whilst, like many of the largest courses of
tin and copper ore in Cornwall, each of them is intersected by a cross vein.
Both the cross veins partake to some extent the character of the ore ground
they traverse. For the most part, however, they consist of slate identical, in
both composition and structure, with the rocks (country) adjoining, that is
to say, they, as well as several of the cross veins of Cornwall, are mere slices
of the strata containing little or no ore.
30.
45
SQ
65
80
३०.
1001
012
124
136
150
Scale 1100yds
Fig. 81.-Parys Mine. Section in North Discovery Lode.
The richest part of the North Discovery (bed) lode is intersected at about
right angles to its course by two nearly vertical joints; but the poorer
portions are traversed by several such seams, all which dip towards the
west.
The body (courses) of ore, both in the great deposit and in the North
Discovery lode, has also a westerly dip endlong, but at a lower angle.
To a depth of 18 fathoms in one part, and of 23 fathoms in another, the
great metalliferous mass was quarried for its entire width. At these
respective levels, however, “not only had the body of ore diminished, but it
G G
450
[BOOK II.
THE FORMATION OF DEPOSITS.
was of lower quality, whilst the expense of raising it had increased inversely
in the same proportion. Quarrying was, therefore, discontinued, and mining
operations were commenced on the richest of the tributary or subordinate
parts-the Black Rock (bed) lode;" which, by aid of a steam-engine set
up at the bottom of the great open cast, is still mined some 65 fathoms
below the surface. The North Discovery lode is worked to a depth of about
112 fathoms (Fig. 81).
The following description of the Parys and Mona mines was communi-
cated to Mr. Pennant by Mr. Paul Panton of Plás Gwyn, Mr. Price's agent.
The description is so good for the date to which it especially refers (1806)
that nearly the whole of it is transferred to this volume.
"The Parys mountain copper vein is very extensive, and contains ore in
bellies of various magnitudes. Such bellies, or bunches, are commonly called
stock-works. The excavations in the mine are in extent agreeable to the
quantities of ore they contained. But it must be observed that these
vacancies were not entirely filled with copper ore, but partially with mineral
stone, or matrix of the vein, mixed with ore and dead ground, which was
requisite to be cut to give room to pursue the ramifications of the vein. This
vein has been worked on a very large scale, upwards of 700 yards, besides
considerable workings to the east and west of this length of ground. This
length includes the Parys and Mona mines, which are both in the same ground
vein. From the boundary of the two mines to the west end of the Parys
mine is an open-cast excavation 200 yards long, 150 yards broad, and from
20 to 40 yards deep, which gives a content of 900,000 yards of removed
natural ground. From the boundary of the two mines to the east end of the
principal workings in the Mona mine is a length of vein of 500 yards, in
which extent there are three large open-cast excavations, out of which full
408,000 cubic yards of natural ground have been taken. Some of the sub-
terranean excavations in this part of the mine are very grand. One of them
is 50 yards long, 30 yards wide, and 40 yards high from the bottom to the
rugged corner of the arch, supported only by one pillar in that cavity. In
another part of the mine is an excavation 40 yards in length, 15 in width,
and 40 yards in one outer arch. The underground workings are too numerous
to particularise. The whole of them will amount to a vacuity of 200,000
yards cubical measurement, besides shafts, levels, &c. Some idea may be
formed of the vast bodies of ore this part of the mine contained by the
quantity of ore raised by two bargains in three months in the year 1787 in
the first, 2,931 tons of good copper ore, and only 92 tons of waste; in the
other, 488 tons of copper ore, and 267 tons of waste, besides the ore raised
by sundry other small bargains."
•
1806. Men employed
Gunpowder used
Candles consumed
""
1807. Men employed
Gunpowder used
Candles consumed
1808. Men employed
Gunpowder used
•
•
227
17,036 lbs.
26,283
:
""
237
15,345 lbs.
23,321
I22
""
6,300 lbs.
9,200 ""
The agent then describes the character of the ores raised and the mode
""
·
""
Candles consumed

CHAP. IV.]
THE OPEN-CAST EXCAVATION.
451
of dressing. The description of arrangement for dressing ores will form
the subject of a separate section, as it applies equally to the processes
adopted to remove the valueless matter from the richer metallic portion
of several ores.
The Parys and Mona mines drain the surface so thoroughly, that for
want of fresh condensing water, four of their five steam-engines are of high
pressure. The Parys mine emits annually about 700,000,000 gallons of water
Fig. 82.-Great Open Cast in Mona Mine.
impregnated with copper. The average product of copper from this is from
55 to 60 tons, and the iron consumed in obtaining it is 600 tons. The copper
found in these waters, as indicated from the precipitate obtained, varies from
4 to 30 per cent., according to the wetness of the season. A sample procured
in the dry season was consequently rich in copper; its specific gravity was
1055 at 60° Fah. The solid contents of one gallon weighed 4,960 grains, which
gave peroxide of iron 1,680 grains, oxide of copper 80 grains, sulphuric acid
3,040 grains, muriatic acid 38 grains, and 122 grains of earthy matters which
were not examined. In order to ascertain whether the copper might be
extracted more cheaply by means of the galvanic current, or by the
electrotype process, than by the ordinary means of precipitation, a piece
of iron wrapped in a strip of brown paper was attached to a piece of copper,
and both were immersed in a solution of copper ore in the muriatic acid to
be examined. The first action which took place, however, was the complete
reduction of the persalt of iron to the state of protosalt, at the expense of
GG 2
452
[BOOK II.
THE FORMATION OF DEPOSITS.
the copper pole; after which the electric current began to effect its object,
the copper being deposited, but from the copper which had been dissolved
having also to be precipitated, the consumption of iron was 658 grains, whilst
the actual increase in weight of the copper pole was only 64 grains, the
quantity of copper originally held in solution. Different arrangements
of batteries were tried, platinum, silver and lead were also substituted for
the copper, but in no case was a deposit obtained from the water until the
iron was first brought into a state of protosalt; when this was effected the
result was 63 grains of copper obtained and 53 grains of iron lost.
Both zinc and iron, when put into the persalt of iron, first reduce the
persalt to the protosalt, which fully accounts for the great consumption of
iron for the small proportion of copper obtained from these waste waters
of mines, and not, as was generally supposed, from the existence of free acid.
The copper is never all precipitated from the water so long as persalt of iron
exists in the solution.
The accompanying section (Fig. 83) gives the positions of the Black
Rock lode, the vast Clay Shaft lode, and Carreg-y-doll lode, the two first
ADIT
HAR
TES LODE
CAIRN S
SHAFT
20
80
70
DRIFT MAWR LEVEIL
ADIT
44
30
65
55
GREAT
OPEN-CAST
LODE
LACK ROCK LO
DYFFRYN ADDA
Fig. 83.-Section in Mona Mine.
being in immediate connection with the "great open cast." The conditions
exhibited in this section are exceedingly remarkable.
It is not easy to
frame any hypothesis which will clearly explain the phenomena under
consideration.
The most probable solution of the difficulties will be arrived at by sup-
posing that the numerous small veins branching from the Clay Shaft lode,
with the other lodes coming to the surface, formed a system of fissures when
the whole was beneath the waters of the ocean, or of a large lake. The
waters under these conditions-probably highly charged with carbonic acid
—would be constantly acting, upon what may now be called the trunk lode,
and be constantly enlarging it. This kind of action is indicated by the space
left between the 55 fathoms and 44 fathoms, and the still larger space extend-
CHAP. IV.]
THE BLUE STONE OF ANGLESEA.
453
ing from the 70-fathom level to the 10-fathom level. The lines representing
the fissure veins will convey to the mind a series of similar spaces which
have not been removed. The conditions which were found to prevail at the
first excavation of the great open cast would appear to indicate that at one
period there existed here a copper deposit, such as was found in the copper
Turf mine of Merionethshire. The copper held in solution, derived no doubt.
from neighbouring rocks, which were full of copper pyrites, as small strings,
or actually disseminated through the rocks, would slowly find its way into the
small cracks, and flow into the larger portions of the lode, gradually parting
with its copper, generally in the form of a sulphide, and at the same time
iron pyrites would be formed and precipitated. If we suppose the open casts
in these mines to represent just such conditions as prevailed in the copper Turf
mine of Merionethshire, it will not be difficult to understand the formation of
the lodes, from which they are still deriving considerable profit. With a
view to rendering this hypothesis clear, a description of the Turf mine will
follow on a future page.
The returns since 1871 from these mines have been reported as follows:-
Copper Ore.
Tons. cwts. qrs.
1871. 2,507 18 O
1872. 2,813 O O
1873. 1,938
1874. 3,343
9
1875. 2,704 4
1 2 3 T
Fine Copper.
Tons. cwts. qrs.
PARYS MINE.
Precipitate.
Tons. cwts. qrs.
167 17 2
155
163 O 0
Fine Copper.
Tons. cwts. qrs.
15 2 O
Blue Stone.
Tons. cwts. qrs.
182
O
13 19 O
I
125 19
62
I
I 20 I2
3
10 16
O
10 о
119 19
10 15
3
205 17 2
150
1876. 2,323
3
I
187
0
1877. 2,154 JO O
42
15
150 о
19
12
2
1878. 320 2
6
7
150 15
19
13
O
1879. 180 O
4
ΙΟ
100 4
12 13
1880.
960 3 O
1881.
863
1 1
7
34
IO
O
119
5 3
MONA MINE.
Copper Ore.
Fine Copper.
Blue Stone.
1871. 3,000 O
Tons. cwts. qrs.
O
Tons.
195
cwts. qrs.
O о
Tons.
cwts. qrs.
Precipitate.
Tons. cwts. qrs.
200 O
O
50 о
о
1872. 2,400 O
1873. 1,628 о
156 O O
105 16 о
984
O
24 I2
414
O
287
O 0
1874. 150
O
9 15
1,008
O
282
о
1875. 600 O O
1876.
800 O O
| |
500
50
О
332
O
O
1877. 1,040 O O
38
O
1
270
O
O
1878. 1,022 I
1879.
766 15
1880. 2,019 O O
1881. 3,804
O
37
O
27
6 O
IO
360
302
16
O
152 5 0
548 10
1,569
1,460 10
IO
202
O
O
О
O
166 O о
409 O
Blue Stone.—A curious ore is found in Anglesea, called by the Welsh
miners Carreglas, or blue stone. It lies generally on the top of nearly all
the great bunches of copper ore, close to the surface of the ground, having
been acted upon by the atmospheric changes of our variable climate during
the course of years. The sulphides of copper and zinc are in many places
carried off in solution by rain water, leaving the sulphide of lead, which is
insoluble in water, behind, in a layer to the depth of two or three feet from
the surface, having the appearance of a dull grey clay. Of this clay-lead ore
large quantities were sold by the proprietors of Parys mine about the year
454
[BOOK II.
THE FORMATION OF DEPOSITS.
1786, and of the silver extracts from it, there were some pocket-piece coins
struck off, in imitation of Parys mine, Druid-head copper pence then
coined.
Mr. Samuel Lucas, of Sheffield, purchased several cargoes of it, which he
conveyed round by sea, from Amlwch to Hull, and thence to Sheffield, where
he smelted it for the silver it contained. There were two samples of the Parys
mine clay-lead ore in 1824, tested with great care by a silver refiner, one of
which produced 65 ozs. of silver in 20 cwts. of lead, or 1'548, and the other
56 ozs. in 20 cwts. of lead, equal to 1640.
The "blue stone" of Anglesea contains sulphides of copper, zinc, and
silver lead. A variety which occurs in Wicklow, Ireland, is stated to be
a compound in equal parts of the sulphides of zinc and lead, containing
silver.
The Turf Copper Mine of Merionethshire.-Sir A. C. Ramsay, in his
"Geology of North Wales," describes the conditions under which the Turf
copper mine was probably formed. Looking with the eye of a geologist,
the quotation given at page 121 is of considerable value. The following
abstract, from a paper by Mr. W. J. Henwood, gives the miner's ideas on
the same remarkable cupriferous turf* :-
"The district to which Mr. Henwood's labours were directed a few years
ago is the wild and romantic one-well known to tourists-about three or
four miles north-west of Dolgelly, on the way to Trawsfynydd, and occu-
pies the irregular triangle included between the rivers Mawddach and
Babi. Although the surface is generally steep and rough there are some
gentle declivities, and small vales so slightly inclined as to have per-
mitted the formation of peat, and it is in these that the copper turf has been
wrought.
"The copper ores which have been found in some abundance amongst the
mountains of Merionethshire have not occurred in such long and regular
lodes as characterise many other metalliferous deposits, but are for the most
part obtained from the network of irregular streams, which, chiefly composed
of quartz and carbonate of lime in ever-varying proportions, and frequently
mixed with epidote and other minerals, conform more or less to the natural
joints of the hornblende, slate, or Greenstone.
“At Burnloch numerous short thin veins and isolated spots of copper
pyrites occur in a small rocky eminence, and the water oozing and trickling
from it enters a field long cultivated, but from its infertility called Cae
Drwg (the bad field'). The soil was examined and gave traces of copper.
"At Benehos there are small quantities of antimonial grey copper ore, of
copper pyrites, and of the blue and green carbonates of copper. The earth
which receives the drainage of the pits sunk in pursuit of these ores gave
slight but unequivocal signs of copper. Copper pyrites occurs at Tyn-y-
myndd, but not abundantly. Immediately below, at Maes-y-Glwysan, the
vegetable mould is about 3 feet in thickness, and reposes on a bed of rotten
wood (hazel?) and decayed roots of grass of six inches deep. No sign of
copper was detected in either of them; but a bed of peat beneath afforded a
"On the Copper Turf of Merionethshire." By William Jory Henwood. ("Report of the Royal
Institution of Cornwall.”)
•
CHAP. IV.]
DEPOSIT OF COPPER IN TURF
455
moderate produce of copper, and has been occasionally wrought. By far the
best known and most extensive deposit of copper turf, however, is at
Dolfrwynog, where some seventy acres of it were worked about forty years
ago, at the base of a hill which forms the southern bank of the Mawddach,
and receives the drainage as well of an extensive common as of a long level
on a vein of quartz in which were found several irregular masses of copper
pyrites weighing some tons each. The chief repository of the copper is a
bed of peat of about 18 inches or 2 feet in thickness, which consists for the
most part of dead grass mixed with great quantities of rotten wood (oak and
hazel). Beneath the peat there is a bed of stones a few inches in thickness,
evidently the débris of the neighbouring rocks. Many of the stones contain
iron pyrites in abundance, and some of them are thinly incrusted with the
green carbonate of copper. A second bed of peat underlies the fragmentary
deposit, and also affords copper, but so scantily that it has not been wrought,
and its thickness has not been ascertained.
"Some of the lower portions of the upper peat-bed were so rich in copper
that they were carried to the Swansea smelting works in the condition in
which they were extracted. Some of the leaves are said to have been covered
with a thin pellicle of bright metallic copper; nuts were coated in like
manner, and on being broken afforded also a kernel of the same; and I was
informed that copper was in some cases deposited between the fibres of the
wood, so that on being cut it exhibited alternate layers of vegetable matter
and of metal.
"These were, however, exceptional cases. Ordinarily the turf was cut and
dried by exposure to the air, and when sufficiently dried it was set in heaps
and burnt. As the mass ignited, recently cut turf was added, which was
soon dried by the heat; but especial care was taken that the burning heap
should not burn into flame, for it then fused into a slag, which would not
suit the purposes of the smelter. All the utensils employed, excepting only
those for cutting the turf, were of copper, as it was found that iron ores were
rapidly destroyed.
"After the fire had been continued for eight or ten days without inter-
mission the ashes were fit for the furnace, and they were then sold to the
Swansea manufacturers. In one year 2,000 tons of ashes had been sold, and
had realised a profit of about £20,000. At the time of Mr. Henwood's visit
there still remained an enormous quantity of copper turf, but as its ashes
would not yield more than about 2 per cent. of copper it was thought too
poor to be wrought to advantage.
"Persons conversant with the copper turbaries consider the presence
of metal in the soil indicated by the growth of the sea-pink or thrift,
Statice armeria, which appears to flourish there with remarkable luxuri-
ance.”
Great Ormes Head.-There are some peculiarities in the deposition of
copper in the beds of this headland which appear to prove that the deposition
of copper ore is dependent on the nature of the rock. The beds in some
places have a crystalline character, which appears to have a very close
relation to the productiveness of the copper-bearing veins. Except when
enclosed in a crystalline rock the veins are scarcely seen to exist, and are
456
[BOOK II.
THE FORMATION OF DEPOSITS.
never productive. The beds a a are the crystalline beds in which the veins
ccc are full of copper ore, whereas in passing through the bed bb they fail
entirely in the production of ore.
b
a
الا:
с
C
C
Fig. 84.
a
V c c
Fig. 85.
##
Fig. 86.
The beds are shown, in Fig. 84, alternating, the deposit of copper in the
beds a a being a constant result. Another effect is illustrated in Fig. 85. The
leading veins c c are sometimes interrupted by cross veins v. These cross
veins are often favourable to the production of copper in the intersections,
especially where it occurs in a favourable bed. The ore is then found to
extend through the whole group, constituting a large deposit of copper
pyrites, through all the beds.
Fig. 86, Copper ore is found at c and b, but none at a d. Yet there is no
heave, the lines a d indicating the continuation of the lode in its non-pro-
ductive state.
At the foot of Great Ormes Head, very near Llandudno, a copper mine
was worked by a Liverpool merchant. He was quietly pocketing a few
hundreds each year, as the profit of his copper mine, when quite unex-
pectedly it was found full of sea water, the ocean waters having found their
way in through some fissures in the rocks. The fissures were eagerly sought
for, and every one found was filled with cement; but they were never for-
tunate in finding the fissure through which the water entered the mine,
and consequently the Llandudno copper mine was abandoned.
Alston Moor Mines, and others in the Northern Counties.-Although some
attention has been given to the geological phenomena of the mining dis-
tricts of the North of England, and the character of the mineral lodes, as
far as the probable modes of formation are concerned has been noticed, it
now becomes important to direct attention to the more characteristic
phenomena which have presented themselves in connection with the opening
of the mines.
The contents of mineral veins in Alston are generally-
1. Rider or veinstone or dowk.
2. Calcareous spar.
3. Cawk spar, heavy spar, or barytes.
4. Quartz spar.
5. Druse (a hard concreted stony crust).
Then white mineral soil, which is frequently lead ore; red fatty clay,
indicating the presence of iron; bluish mineral soils; yellowish, ash-
CHAP. IV.]
THE MINES OF ALSTON MOOR.
457
coloured, and marbled soft soils, called mother by the Scotch miners; black
and brown mineral soil.* The most promising of the soft mineral soils is of
a brown colour, and of a lax and friable texture. This, arising no doubt
from decomposition, is a variety of a gossan as it is called. The Riders of
some strong veins are so hard as to resist the action of atmospheric causes.
The great vein at Nun-stones, near Tynehead, is conspicuous as a pile of
rocky ground at a considerable distance. The Nun-stones great copper vein
(denominated in a lease, as Mr. Sopwith tells us, "the back bone of the earth")
is the largest and strongest vein in Alston Moor. Where it passes Cross-
gill Burn it is no less than 300 feet in width, and it throws up the strata
80 feet. Mr. John Taylor supposed this vein to be rather a collection of
branches than one single continuous vein. He thought copper might be
obtained in payable quantity in depth,-especially where it intersects Stow-
crag vein,—where a rich but not large deposit of copper was found.
Regular ribs of ore occur in wide veins, running parallel to the rib and
the rider. A rider in a vein is not, in the Alston Moor mines, always found
in a continuous rib. Irregular masses of rider, and of ore, are found of all
dimensions, "from the size of a fist up to the size of a hogshead, and much
bigger" (Williams).
The working of the Alston Moor mines in olden time was exceeding
primitive. Rude shafts were sunk into the vein, and when required, levels
were driven into the hill to drain off the water. The lead ore was taken
through the drifts (levels) by boys, and drawn up the shaft in kibbles or
small tubs by a whimsey or roller worked by men or horses. Men or boys,
according to the extent of the mines, drew the ore up the sumps (shafts
underground connecting the levels with each other) which are formed from
the deep workings. The levels were small, just sufficient to admit the
workmen. They were rarely more than 4 or 5 feet in height, about 2 feet
wide at the top, and from 15 to 16 inches only at the bottom. Though
called levels, these ways or galleries were often much inclined; some-
times the ascent was as much as 45º.
At the commencement of the present century a spirit of enterprise led to
considerable progress and improvement in the mines of Alston Moor. A
writer at this time says: "The mines in Alston and Allendale are conducted
on the most scientific principles, and the agents are men of skill, and well
versed in mechanics."+
The discovery of Hudgill Burn mine caused great excitement, and led to
the formation of several companies of mine adventurers.
The Flow Edge Mining Company commenced a trial of Middle Fell
mountain. They drove a level 250 fathoms, and found only two small veins.
They sunk two shafts from the surface, and a sump to the four-fathom Lime-
stone. They also drove a level to the north, and having discovered a vein
made a rise to the middle of the Great Limestone, which vein they explored
for 20 fathoms, finding only a few samples of ore. This company lost
about £2,000. They abandoned the workings, and the mine was unworked
for eight years. In 1812 Messrs. John and Jacob Walton obtained leave to
* Williams, "Natural History of the Mineral Kingdom.”
† Mawe, "Mineralogy of Derbyshire."
458
[BOOK II.
THE FORMATION OF DEPOSITS.
make a new trial. Four men were employed to drive 20 fathoms of level
at £4 4s. per fathom, by which they made 16s. a week. This continued for
nearly two years, the average of the bargains being about £3 10s. per
fathom. In this time they drove 70 fathoms.
In April, 1814, a vein was discovered of good appearance, but so situated
that it would not pay for working. They drove through this vein, which was
2 feet wide. A rise (i.e. a working upwards into the strata) was made to the
Great Limestone, and the vein was found nearly filled with carbonate of lead,
or white lead ore. Four miners took a bargain to work the vein at 18s.
per bing (of 8 cwts. each), until midsummer (nine weeks). By that time they
had raised 800 bings, and cleared £80 per man. The workings were now
continued at wages of nearly £10 per week. The veins of Hardgill Burn have
since produced ore from 10 to 12 feet wide, and in some places the width
increased to 20 feet. The company spent about £360 before they reached
the vein, and altogether about £2,300. Its produce in 1820 was 9,000
bings of ore. In 1829 the horse levels in it were more than four miles
in length, and the value of the silver produced in 1821 was £8,400. The
profits of this mine for many years appear to have averaged £30,000 per
annum.
In 1812 the Commissioners of Greenwich Hospital agreed to purchase
the ore from such mine adventurers as had no smelting establishment,
and they were thus rendered independent of the fluctuations of the
market.
In 1817 Langley Mills were erected chiefly for the purpose of smelting
the ores of zinc. These for a few years were successful, but the price falling
from £70 to £40 per ton, the concern was abandoned, and for some time zinc
was imported from Germany, at less price than the English smelter could
produce it.
There is a fact connected with the lodes of Alston Moor which must not
be neglected. In the North of England generally, the north and south veins
divide those running east and west, in almost every instance. The excep-
tions are very few. The divided vein, if it hades, and the vertical throw of
the cross vein be considerable, will be displaced, so that its divided parts
remain parallel, but on coincident planes, and viewed in a horizontal
section appear to have suffered a lateral movement. Of the pipe veins a descrip-
tion has been already given. Williams gives numerous examples of pipe
veins, and of streek, flat, or dilated veins. He denies that any of these are fissure-
veins. He says: "In fact they are no fissures, but a space or opening between
two strata, or beds of stone, the one of which lies above, and the other below
this vein, in like manner as the roof and pavement of a stratum of coal are
above and below that coal. When the strata between which this vein is
found lie nearly parallel to the horizon, the vein is likewise in the same hori-
zontal position; and when the strata vary from the horizontal position, the
dilated vein varies likewise with the same degree of declivity, and this of
necessary consequence, as the vein does not burst the strata, but always
continues between, the same two beds of stone. Some English miners call
the flat veins strecks, and when they have both a rake vein, and one of these
in the same field, they distinguish them by the appellation of the vein and
•
CHAP. IV.]
LODES IN THE LOWER LIMESTONE.
459
the streek. By the word streek they mean stretch, or a vein between the
strata which stretches or spreads in a horizontal position."
The following is abstracted from a list of the lead mines "which are, or
have been worked in the manor of Alston, in the county of Cumberland,
belonging to the Commissioners and Governors of Greenwich Hospital,
including the mines at Cross Fell and Tyne Head, together with an account
of the mineral substances they produce," by Westgarth Forster. †
Alston Moor
""
Allendale
Derwent
Weardale
Teesdale
Westmoreland
69 mines
·
Lead.
•
•
3
""
•
7
3
36
38
12
""
""
•
Copper (Back-bone, Corn-riggs, East-burn).
Lead.
Lead.
Lead.-Belongs to the Bishop of Durham,
formerly principally occupied by Colonel
and Mrs. Beaumont.
The property of the Earl of Darlington.
The property of the Earl of Thanet.
In relation to the Alston Moor district, and indeed to all the mining
tracts of the northern counties, there exists a peculiarity which does not
admit of easy explanation. Is there any distinctive difference in the metal-
liferous characters of the Upper and the Lower Limestones? We know that
one is highly metalliferous, and the other rarely so. Mr. Wallace, looking at
the geological conditions, with especial reference to his own views, relating
to the laws of hydrous agency, remarks: “In Alston Moor the position of the
series of beds called the lower strata is more varied than the group forming
the upper strata. In some places they are considerably elevated above the
bottom of the valleys, or even basset at the summit of the mountains; in
others they lie buried at great depths, the whole of the upper portion of the
Mountain Limestone, and part of the Millstone Grit, reposing upon them. In
the former case, the conditions for promoting the percolation and circulation
of fluids in the veins vary in a manner similar to those connected with the
veins in the upper strata. In the latter, because of their being so far removed
from the surface, very little variation can occur. The subject may therefore
be viewed under two aspects: the conditions connected with the deposition
of lead ore in the veins near the surface, and those connected with its deposi-
tion at great depths below." Remembering that the same veins which have
produced enormous quantities of lead ore in the upper strata are very poor in
the lower, and also bearing in mind that the condition of mineralization in
each case must be similar, it is difficult to arrive at any other conclusion than
that the variation arises from some difference in the ages of the two sets of
rocks, the lower stratum being, of course, older than the upper stratum.
The evidence we have appears to favour the idea, that the period of mineral-
ization was after the formation of the upper beds, and that they acted as
filtering media for all the fluids collected from the surface of the country or
from the upper rocks, the water being deprived of all, or nearly all, its
metallic salts by passing through them, thus forming the more productive
lead veins. It must be borne in mind that the same fissures which have
* "The Natural History of the Mineral Kingdom,” vol. i. p. 339. By John Williams. 1789.
† "A Treatise on a Section of the Strata from Newcastle-upon-Tyne to the Mountain of Cross Fell,
Cumberland, with Remarks on Mineral Veins in General; also Tables of the Strata in Yorkshire and
Derbyshire. Second edition, greatly enlarged. By Westgarth Forster. 1821. A third edition has
been published recently.
""
460
[BOOK II.
THE FORMATION OF DEPOSITS.
become rich in lead ore in the upper parts, are poor in the lower, the con-
ditions for mineralization being very similar in each. The difference
between them must arise from a greater portion of ore-producing matter
entering, in probably a fluid state, into the fissures of the upper bed, than can
flow through the lower part of the same fissure." Mr. Wallace, whose views
in general are not exactly those usually entertained, gives a good example.
He says: “To particularise one case, the Browngill veins, on the west side
of the outcropping of the Great Limestone, are connected with conditions
very favourable for promoting the percolation and circulation of fluids.
Had these veins traversed the upper series of strata, and the Great Lime-
stone occupied the position of the Scar Limestone, there can be no doubt
whatever but that they would have contained very rich deposits of lead ore
instead of the few poor ones, which, with one or two exceptions, have not
repaid the cost of extraction." The following table represents the position
of the Great Limestone bed relative to the Scar Limestone and the
Whinstone-Sill.
a. Ten small beds of hazle
1. Fell top Limestone
•
b. Nine beds of hazle, ironstone, &c.
2. Little Limestone
c. Five beds of coal sill
3. GREAT LIMESTONE
d. Two beds tuft and hazle
4. Four fathoms Limestone
e. Natrass gill hazle
5. Three yards Limestone
f. Six fathoms hazle
•
6. Five yards Limestone
g. Slaty hazle
7. Upper SCAR LIMESTONE.
•
•
630
10. Little Limestone
•
11. Smiddy Limestone
n. Hazle
12. Limestone
Ft. in.
Ft. in.
4 6
k. Three Beds of hazle
9. Jew Limestone †
24 0
1. Slate
60
18 0
m. Hazle
31 6
•
25 6
21 0
•
132 0
•
•
24 O
90
15 0
30 о
•
24 0
h. Alternating beds copper, hazle, &c.
8. TYNE-BOTTOM LIMESTONE
i. Whetstone Bed
1. WHINSTONE-SILL (120 feet)
0. Hazle
•
13. Robinson's lime.
p. Hazle
•
•
14. Melmerby SCAR LIMESTONE
q. Several beds of freestone and coal,
with two thin beds of Limestone, to
the total thickness of the whole of
the strata of 1,133 of Sandstone,
1,181 of plate, 480 of Limestone.
+
+
Referring to the section of the strata which has been given, it becomes
interesting to learn the real condition of the beds (especially of the Limestone
beds) in their metal-bearing characters. Nearly all the mines are found to be
productive in the upper beds only. This condition indicates, that the lead-
producing cause, whatever it may have been, was not established when the
deeper beds were in process of deposition. The character of the deeper
mines is given below. For these particulars we are indebted to Mr. Adam
Walton, the Moormaster of Alston.
"At Rodderup Fell the miners have reached the 'Jew Limestone,' which
they have found to be comparatively worthless-unless at Smittergill—where
but little has been done successfully. Rodderup Fell is the only mine in
this county in which the 'Jew Limestone' has been worked, or which has
been reached.
* The Great Whin-Sill is a basaltic Greenstone, similar to that which occurs at Salisbury Crags and
at the Giant's Causeway. Mr. Winch ("Geological Transactions," vol. iv. p. 79) says the Great Whin-Sill
of the lead-mine district does not consist of the whin of the colliery sinkers, but is really basalt, coarse-
grained in texture, and composed of white felspar and black hornblende.
†The Jew Limestone. At Hilton lead mine this stratum is close to the bottom of the Great Whin-
Sill, and is nearly eighteen fathoms in thickness.
Below the lowest plate bed we find six fathoms of freestone, a bed of Limestone, the lowest
calcareous stratum of the section; below this the Red Sandstone occurs in irregular beds.
CHAP. IV.]
66
(
THE RODDERUP FELL VEINS.
461
"The Tynebottom Limestone,' next above the 'Jew,' has been worked
at the following mines:-
Metal Band (worthless)
Tees Side (moderate)
Providence (poor)
Lady Vein (poor)
Dosey (fair)
Tyne Green (fair)
Pattersyke (poor)
•
Stow Craig (lead and copper moderate)
Ashgill Field (poor).
Tyne Bottom (fair)
Windshaw Bridge (rich)
In Colonel Byng's Tynehead Manor.
In London Lead Company's Priorsdale Manor.
In G. Hospital's Manor."
They are working in a Limestone at present, at the "Green Hurth" mine
in the Duke of Cleveland's manor, which they suppose to be Tynebottom
Limestone; the results are uncertain. The value of the lead mines in Alston
Moor in the last century, as obtainable from the moormaster's book, was as
follows in the three years given :-
£
s. d.
"1
In the year 1766, 18,600 bings (8 cwts.), worth on an average £2 15s. per bing 61,950 o O
1767, 24,500
""
1768, 18,730
""
77,162 10 O
62,213 10 O
To the general poverty of the veins in the Lower Limestone of Alston
Moor, Rodderup Fell presents a remarkable exception, large quantities of
lead ores having been produced since the mine was first opened in 1831.
A prejudice, if it can truly be so called,-exists amongst the miners of
this district against the Lower Limestone strata producing lead ore. A
few trials have been made by sinking into this Limestone, but they have
rarely been productive of any favourable result. Mr. Wallace says:
"Between Calvert and Rodderup Fell veins, the east and west veins have
contained scarcely any ore. Trials have been made to prove them in
localities where the conditions for promoting a free percolation and circula-
tion of fluids are as favourable as those connected with veins in the upper
beds, which have contained rich deposits of lead ore; thus tending to
support the hypothesis that the poor deposits of lead ore in the veins in the
lower beds are due to the paucity of some unknown lead-ore-producing sub-
stance not entering so abundantly as a component part of the enclosing
rocks."
The Rodderup Fell vein is supposed to be a combination of two veins
called Craig-Green Middle and How Hill veins. It is wide and well
mineralised; it throws up the north cheek about 15 feet. The situation of
this vein is considerably to the south of the steep banks of the Black Burn.
The course of it is at a considerable distance from the summit of the
hill, and the elevation of the surface is not very rapid. The strata in this
locality have a very rapid inclination, and the dip must be nearly at right
angles to the direction of the Great Sulphur vein; consequently, on the line.
of the Rodderup Fell vein the strata rise in a direction from the east to the
west; the circulation longitudinally in the open spaces in the veins in hard
strata must therefore have been to the east.
It will be seen by the small map (Fig. 87) of the Rodderup Fell veins
that the strata have been much fractured by intersecting leads and veins.
462
[BOOK II.
THE FORMATION OF DEPOSITS.
The parts of the main lode which are indicated by a darker line are the
productive sections of the mine.
The whole of the east and west veins, which traverse Middle Fell, and
cross the vale of the Nent between Long Cleugh and Gallygill Syke veins
inclusive, fall into those portions of Rodderup Fell vein containing the
richest deposits of lead ore. No doubt the numerous small leads-channels
—well marked in the map, which represent respectively the Dryburn Washpool
veins, Dryburn vein, and Dryburn Peak Fell vein, have been the courses
in which fluids have been collected, and conveyed to Rodderup Fell vein.
It is a curious fact, noticed by Mr. Wallace, that all the fluids, after
flowing in the leads in a north-western direction, should be forced to flow in
an opposite way, or nearly east. Rodderup Fell vein is intersected by two
RODDERUP FELL.
HOUND
HILL.
RYDUAN
DRY BURN
WASHPOOL VEIN
VEIN
DRYBURN PEAT FELL VEIN
RODDERUP
RIVER
TYN
GREEN GRAC|||V|
VEIN
CREENCASTLE
STRONO
TARN
VEIN
CREENCASTLE N. VÈIN
RODDER UP CLEUCH
FELL
RODDERUP FELL V
SMITTERGILL S. VEIN
WEATHERAL MEA VEIN
HOWBURN MOSS
YCTORIA
YEIN
SMITTERCILL HILL
CAWARD, HILL
DRY BURN COPPER VEIN
BROWNSIDE.
BLA
KBURN
Fig. 87.-Rodderup Fell Mine.
cross veins, which throw up the west cheek, and many think it is due to this
that it has contained very rich deposits of lead ore in the strata elevated by
the throw of these cross veins.
A close examination of the map of a portion of Rodderup will show
that the richest portions of the veins (indicated by blacker lines) are
where there have been lateral feeders. The fluids flowing through the
smaller fissures appear to have taken up metalliferous matter from the
rocks, which has been again deposited, to form larger masses in the main
lode, where there was some disturbance produced by the flowing in of the
smaller streams.
The conditions prevailing at Smittergill Head mine appeared to be
similar to those prevailing at Rodderup Fell. An industrious and expensive
CHAP. IV.]
LEAD MINES IN DUFTON PIKE.
463
search was carried on for some years, but as the result was not equal to
the expectations, the mine was eventually abandoned.
Dufton Lead Mines, Westmoreland.-Dufton is situated near what was
formerly the great coach road from London to Glasgow. The Dufton
mine lies 3 miles north of Appleby, on the west of a range of hills which
extends from the borders of Scotland, and includes Cross Fell and the
mining district of Alston Moor. The following account is obtained from a
paper published by Professor T. Allan, of Edinburgh.* After describing the
peculiarities of the country around Dufton Pike, which is entirely composed
of Red Sandstone covered with alluvial soil, Mr. Allan says: "The ravine
in which the mines are wrought may be about half a mile wide at the
entrance, and extends from Dufton Pike about a mile and half.
. I
observed Slate rock sufficient to mark the existence of the transition series,
and on it rested strata of Limestone and what is denominated in the country
hazle-sill, which I found to be a thick bed of pale-coloured Sandstone.”
In the beginning the vein was wrought on the summit of the western
front of the precipice, and the lead procured by hushing (that is, by bringing
a stream of water to run over the place where it cropped out).
A level was
subsequently driven through the very solid Greenstone-known as whin-sill—
which was constructed with great judgment. The mine was well ventilated
and very free from water. The Greenstone is, at Dufton, at least 20 fathoms
thick, but in Teesdale it extends to 60 fathoms. It is here interposed
between two beds of Limestone, the upper bed being 4 fathoms thick and the
under bed only 3 yards. The lead is worked in both of these Limestone
beds, and is thus described by Mr. Allan :-
"The vein passes through all the three beds, but is prolific in lead only
in those of Limestone. There it widens out into plates, filled with spars and
metal; but in the Greenstone it is compact and narrow, still, however,
producing a small particle of lead now and then, as if to identify the course.
Beyond the range of these three beds the workings were not prosecuted, and
I could not learn what appearances the vein at these extremities assumed.
The nature of the strata, both above and below, appeared very unusual;
over the 4-fathom Limestone a bed of plate (very friable shale) occurs, then
a Sill of Hazle, with some small seams of coal; under the lower bed of
Limestone another bed of Hazle and strata of coarse Limestone appeared ;
and these I believe to rest upon the transition rocks.
"At the extremity of the north side of the ravine there is a hill, connected
at its base with that in which the ravine is. It is singular to observe how
abruptly the metalliferous strata are cut off; these jut boldly out, and
exhibit their regular horizontal position distinctly to view; while the hill,
whose base touches upon that on which they rest, presents a rugged surface,
composed of strata set upon edge.”
It is remarkable to observe the lead lode-being rich in that mineral in
the Limestone, and almost declining to nothing in the Greenstone.
The author visited these mines with Mr. Wallace in 1864, who then had
the management for the Governor and Company of Lead Miners.
*"A Geological Account of the Lead Mine of Duſton, in Westmoreland." By T. Allan, &c. &c.
("Journal of Science and Art." Edited by W. T. Brande, F.R.S.)
464
[BOOK II.
THE FORMATION OF DEPOSITS.
Teesdale.-The water division between Alston Moor and the Dale of
the river Tees is called Heaven's Water division,—a rivulet called Crookburn
being the actual boundary between the counties of Cumberland and Durham,
and the parishes of Alston and Middleton in Teesdale. As far back as the
reign of Edward III., the Scottish army, then encamped in Weardale, made
their escape from him, by laying boughs across Yadmoss, to prevent their
sinking in the bog. It was not until 1824 that a passable road was made
there, so long did this Dale remain in its primitive state. The principal
veins run east and west, and the hade, or inclination of the vein, is north.
As a rule the upper Plate shales, often reaching the surface, are most
productive. In some cases the 12-fathom Limestone has yielded considerable
quantities of ore, but the deposit in it is very irregular.
Generally the vein is wrought at so much per cubic fathom, and in other
cases at so much per bing; the workman pays for drawing the ore, and if
engaged at so much per bing, also for dressing, which amount is deducted
from his yearly account.
The principal part of the ore is raised on the manor of the Duke of
Cleveland, and a duty is charged of one-sixth. The Governor and Company
had also ground leased of Mr. S. Hutchinson, J. Bowes, and of the Bishop of
Durham, or, the Ecclesiastical Commissioners. The average percentage of
lead in the ore is about 75, and the silver is generally about 10 ounces per
fother of 21 cwts.
As a means of saving the lead from the smelting fumes, 1,400 yards of
chimney are used, terminating in a shaft over 150 feet in height. During
the passage of the smoke through the chimney, it was subjected to a process
of filtration, by means of a bed of rubble stones, while self-acting buckets are
suspended above, which are each supplied with water. When about three-
quarters full they turn over, emptying their contents on the stone bed,
washing off the lead which has collected.
Forster, in his "Section of the Strata," enumerates thirty-eight mines in
Teesdale, all of which, with a very few exceptions, were in the occupation
of the London Lead Company. The mines at Manor Gill and Lodge Syke,
near Middleton, have been immensely rich. The London Lead Company's
smelting works were erected about half a century since by the London Lead
Company, under the immediate direction of their manager, Mr. Stagg. The
importance of the Governor and Company in the history of mining, espe-
cially their early experiments on smelting lead ores with coal, demands
some especial notice.
In the early part of the reign of William and Mary (1688-94), a lady
—a member of the Society of Friends-witnessing the destitution amongst
the working classes, especially in the north of England, was induced to
bring the matter before one of the annual meetings of that body. This lady
suggested the formation of a company, which would not only confer-by
employing them—a great boon on the destitute part of the population, but
secure a satisfactory return for the capital expended. This led to further
investigations, which resulted in the formation of a chartered company
under the title of The Governor and Company of Lead Miners. For the
first century, although a considerable amount of lead was raised, and
CHAP. IV.] GOVERNOR AND COMPANY'S LEAD MINES.
465
great improvements were made in the smelting operations, the expecta-
tions of the projectors do not appear to have been realised. About 1750
the company were employing only eight men in their underground
operations, and they contemplated employing their capital in some
more promising speculation than lead-mining. Lodge Syke was one of
some plots of ground in Teesdale leased to four local speculators, who,
after making a number of surface trials by' hushing, allowed their lease
to expire, under the impression that there was no prospect of reasonable
remuneration. The Governor and Company took this sett, but with no
very satisfactory result. They called in two agents to examine and advise
them. One of these proposed to entirely suspend operations, pronouncing
Teesdale to be so unproductive that he considered it foolish to attempt to
develop its mineral resources. The other advised the workmen to try a
hush on another part of the ground, the result being the discovery of a
vein richly charged with ore, close to the surface. This gave a new impetus
to labour, and those who were able and willing found remunerative employ-
ment. Mr. R. Stagg, who was made superintendent of the works, erected a
crushing-mill. He made new arrangements for working the sieves used for
jigging or hutching the. bouse or rougher part of the work, and he intro-
duced the German swing buddle. The mines were wrought from that time,
not only with an eye to the profits of the masters, but also to the safety of
the miners. The overmen were selected from the most intelligent, sober,
and industrious workmen. A commodious school was erected, and cottages
were built, and, at a low rental, were allotted to the most deserving of the
workmen. From that time the district of Teesdale has been a produc-
tive one, producing, in 1881, 5,090 tons 15 cwts. of lead ore. The Alston
Moor mines, especially at Nenthead, in Cumberland, were also in their
hands, and in addition to Silverband in Teesdale, they worked Cornish
Hush, Whitfield Brow, and others at Bollyhope in Weardale.
·
The Governor and Company also possessed mines in Wales, and smelted
ores on the Dee, at Bagillt. The letters L. C. (London Company) were still to
be seen in the plaster of a smelting-mill at that place, a few years since.
They also held for some years the Great Laxey mine in the Isle of Man,
the Lead Hills mines in Scotland, the Millfield mine in Derbyshire, and
the Derwent and Stanhope Burn mines in Durham; and, so extensive were
their operations, in addition, this Lead Company worked the Dufton and
Hilton mines in Westmoreland, and Lunehead in Yorkshire.
It cannot but prove instructive to examine the state of the mines
of the North of England, as they were in 1821, and to contrast them with
those working at the present time. For the earlier date Westgarth Forster's
"Section of the Strata," and other works, have yielded much information.
After leaving the coalfield, the first mine is Healyfield, which is a very
ancient one. Forster says of it: "It has been worked for a great number of
years, and still continues to produce lead, although in smaller quantities
than formerly." In 1881 Healyfield produced 181 tons of lead ore, pro-
ducing 2,170 ounces of silver, the value of the produce being 1,640. The
next mining field is that of Shieldon, one mile west of Blanchland, in
Derwent, Durham. The workings were for some time in the hands of the
нн
466
[BOOK II.
THE FORMATION OF DEPOSITS.
London Lead Company, and they obtained much ore from the upper strata ;
but, until recently, these mines have not been successful.
The produce of the Derwent mines for the last eight years has been as
follows:
Lead Ore.
Tons. cwts.
Lead.
Silver.
Tons. cwts.
Ounces.
1874.
1875.
312
7
231 2
2,048
£
5,198
Value of Ore.
S. d.
2 2
401 5
281 16
2,445
5,943 I 3
1876. 328 3
227 13
1,548
4,745
1877. 409 16
275
8
3,850
5,533
1878. 418 O
292
12
4,038
4,420
227
IO
9
O
1879. 385
289 O
4,335
4,050 7 6
1880. 469 17
281 15
1,412
5,483 о 7
1881. 325
195 5
975
3,268 II 10
In the above returns the lead ore from Jeffrey's rake, about two miles
south-west of Shieldon, are included.
Contiguous to the Derwent mines are those of Allenheads, which have been
in the Blacket family for a century and a half. The mines in Weardale have,
for a considerable time, been in the hands of W. B. Beaumont, M.P., who
has recently surrendered them to the Ecclesiastical Commissioners.
The produce from these mines for the last five years has been as
follows:-
Lead Ore.
Tons. cwts.
Lead.
Tons.
Silver.
Ozs.
1877.
Allendale and
Weardale
Allendale and
•
} 9,821
O
7,366
30,894
Value of Ore.
£ S. d.
116,012
10 O
1878.
Weardale
4,267
4,267 O
3,593
21,157
45,105
ΙΟ 0
•
Allendale.
1879.
584 8
Weardale
1,218*
6,080
•
1,039 ΙΟ
17,052
оо
Allendale.
1880.
550
ΙΟ
Weardale.
5,076*
27,669
3,359 14
37,145
O O
Allendale.
1881.
447 18
Weardale.
2,825
2,454
16,968
36,120
o o
42
The mines in this district are mostly worked in soft strata, the veins
commonly containing much soft fluor-spar. An old mine called Brecon-side,
working in 1809, furnished for many years 10,000 bings per annum.
The remarkable dyke called Burtree Dyke, and its influence on mineral
veins, must be particularly noticed. This is a cross vein of immense
magnitude, and may be advantageously seen near Burtreeford in Weardale,
and traced, crossing the Burhhope, a little above Wearshead. It may also be
seen in Inshope and Langdon. The throw may be ascertained by observing
that the Great Limestone forms the bed of the Inshope, on the east side of
the dyke, and that on the west side, the same rock is found upon the top
of the ridge, where the mountain track goes over it to Grass Hill. This
upcast is at least 80 fathoms, the west side being elevated to that extent. The
several beds of rock rise rapidly towards the dyke on each side, forming in
some places an angle of 45° with the horizon. It is deserving of notice that
the elevation, or depression of the strata, by veins is usually very limited in
extent, for at a distance of half a mile from the strongest, the several beds are
found to occupy the place which their general position and rise would assign
them. Before leaving this subject we desire to give an estimate of the
average produce of the mines in Teesdale, Weardale, Allendale and Alston
*Much of the ore raised in 1879 was not smelted until 1880.
CHAP. IV.]
ALLENDALE AND WEARDALE MINES.
467
Moor, including the mines at Cross Fell, along with some other mines in
Westmoreland, from the year 1800 down to 1821. It is important to preserve
every record we can obtain of our mineral produce.
Teesdale mines, in the county of Durham
Weardale mines
""
Allendale mines, in Northumberland
Alston Moor and Cross Fell, in Cumberland
•
Bings per annum.
8,000
Dufton Fell, Dun Fell, and Hilton mines, in the county of Westmore-
land
Total.
17,000
8,000
•
19,000
1,500
53,500
The deposition of lead ore in the Allendale Mines is altogether remark-
able. We find there rake veins, and flat or dilated veins putting on very
varied characters, sometimes assuming the conditions of beds, or of the
flat lodes, and carbonas of Cornwall. Frequently singularly rich cavities of
lead ore have been found in the Great Limestone. All the conditions point to
the action of water highly charged with carbonic acid, which has been, for
long periods of time, acting by dissolving the lime and thus forming caverns;
these subsequently being filled with lead ore, by a gradual deposition of it
from fluids, bringing the metal in solution from the neighbouring rocks.
Westgarth Forster informs us that some of these caverns have produced
upwards of 400 tons of ore, most of it "being found in a loose state upon the
soles of the cavities, which has probably fallen from the roof at some remote
period of time." We may infer from this that, by the percolation of water
through the Limestone, stalactitic masses of galena were formed, which
eventually were broken off by their own weight, and deposited at the bottom
of the caves. The Great Burtree-ford dyke has produced a great dislocation
which has disturbed all the veins. Those veins have not been thoroughly
proved, and therefore a new mining district may, in future years, be created
by some bold and judicious adventurers.
The mining field of Allenheads has been very extensively worked by
Mr. W. B. Beaumont, M.P., under the experienced scientific management
of the late Mr. T. Sopwith, a gentleman who was well known for his excel-
lent works on mining, and for his beautifully-constructed models of mines
and mining districts, which may be studied in the Museum of Practical
Geology with great advantage by all who contemplate embracing mining
as a profession, or adventuring in mining explorations. Owing to the low
price of lead, these mines have not been profitable for the last few years, and
they have been recently abandoned, leaving a large population, drawn to
the district by this important industry,-which has yielded a princely fortune
to the lessee in past years,-in a state of considerable distress.
Swaledale Mines, Yorkshire.-There are a few points of interest which
occur in the Swaledale district to which attention is required. The principal
portion of the lead raised in Swaledale has been obtained from the Limestone
beds. Some idea of the value of the production of lead ore from the mines
of Swaledale may be formed from the following returns of four years when
they were at their richest :
In 1857, 5,537 tons of lead ore.
""
1858, 6,576
""
In 1859, 5,717 tons of lead ore.
,, 1860, 4,878
">
H H 2
468
[BOOK II.
THE FORMATION OF DEPOSITS.
The mines of Swaledale are as follows, and their present condition will
be apparent by the returns of such as are productive :—
Arkengarthdale
Beldi Hill .
Blakethwaite .
Ellerton Moor
Fell End
Grinton Moor.
•
1880.
1,659
1881.
1,959
Hurst
Old Gang
Surrender
11
2
3
Swinnerside
1880.
1881.
55
650
294
108
•
103
West Swaledale.
Whiteside.
Distributed over an area of about 200 square miles, there are 192 distinct
veins known in Swaledale, and of these 170 are returned as having produced
lead. The miners of this district place great reliance on the character of
the rider in a vein, as an indication of its probable productiveness.
The rider of the northern miner is any mineral matter existing between
the sides or walls of a vein, the thickness of the rider being determined by
the width of the vein. This rider is usually divided into the fragmentary or
primary rider, and exists in three forms: the Limestone rider, the Chert rider,
and the Grit rider; these names indicating that the veinstone has been
derived from the rocks through which the vein passed, that it is indeed
broken portions of the adjacent beds, cemented by the infiltration of water
containing calcareous matter.
The Mines of Wicklow and Wexford, &c.—Mr. Thomas Weaver,* in his
"Memoir" read before the Geological Society on the 15th May, 1818, deals
especially with that portion of Ireland which is bounded on the east by the
Irish Channel, on the south and west by the mountains which confine the
Suir and the Shannon, and on the north by the hills of Louth, Meath, Cavan,
and Longford, and by a line produced from thence to the Bay of Galway. In
his examination of the Granite, Mr. Weaver says: "The minerals which I
have incidentally observed disseminated in the Granite, or imbedded in the
contemporaneous veins that traverse the rock, are schorl, tourmaline, garnet,
beryl, rock crystal, epidote, heavy spar, magnetic iron ore, galena, copper pyrites,
and iron pyrites." Dr. Taylor informed Mr. Weaver that he had discovered
in the Granite malachite, arsenical pyrites, tinstone, spodumene, and a new
mineral called killinite. The occurrence of the ores of lead and copper, in
quantity, in the Granite is so rare that it deserves especial attention. This
appears to militate against the hypothesis that "rock conditions" are
important in regulating the deposit of ores. Mr. Weaver remarks on the
discovery of tin: "It is an interesting fact, that this metal should at length
have been discovered in the rock in this county, although found only on a
contemporaneous vein traversing a loose block of Granite, for its existence in
the county of Wicklow in the form of stream tinstone had been ascertained
several years ago, by the operations of the directors of the works at Croghan
Kinshela."
The eastern mountain chain of this district is remarkable for being very
metalliferous, while the western side of the Granite region is equally remark-
able for the total absence of metalliferous ores. The lead vein of Dalkey
is situated near the north-eastern extremity of the eastern tract, and it
"Memoir on the Geological Relation of the East of Ireland." By Thomas Weaver, M.R.I.A.
("Transactions of the Geological Society," vol. v. 1821.)
CHAP. IV.]
LUGANURE AND GLENDALOUGH MINES.
469
ranges in the Granite north-west and south-east, dipping 70° to the north-east.
The outcrop of this vein is seen on the coast, from 4 to 5 feet wide. It is
composed of disintegrated Granite, with quartz, in which some green lead ore
-no doubt the result of chemical action—is seen; and, in the refuse of the
mine, which is filled with sea water, galena, blende, and barytes are found.
At Ballycorus there are two veins ranging in the same direction, but one
of those veins dips to the north-east and the other to the south-west. The
veinstones are quartz and heavy spar, which bear lead ore in short bunches
from a few inches to 1 and 2 feet in width, and varying in length from 1 to
3 feet, consisting of fine-grained galena, yielding 75 per cent. of metal, with
carbonate of lead, blende, and pyrites.
To the west of Lough Dan is a vein traversing the Granite brow of Carrig-
geenduff, and ranging across the valley. This vein is from 3 to 4 feet wide,
and dips 80° towards the east. A little galena is found in bunches, and
disseminated, with occasionally a small quantity of copper ore.
Luganure vein runs wholly in Granite. Its course is about 1,000 fathoms
in length, and it has been explored to the depth of more than 200 fathoms.
It dips 65° towards the west. This vein has yielded in many parts from 3 to
4 tons of galena to the fathom, either in layers parallel to the walls or in dis-
seminated masses. Blende is not uncommon, and copper pyrites also existed.
The following is a statement of the production of Luganure for the twelve
years ending 1881
*
Lead Ore.
Tons.
1,336
Silver.
Ozs.
Value of Ore.
£
Lead.
Tons.
1870
1871
1,002
•
•
1872
1873
1874
1875
•
1,085
925
1,180
I,749
1,850
813
701
•
•
885
•
1,311
6,555
20,988
·
1,387
6,925
•
20,354
1876
1,825
·
1,368
6,840
•
20,077
1877
1,655
•
I,241
6,205
•
18,214
•
1878
1,526
•
1,150
•
•
5,650
12,208
1879
1,124
800
4,000
7,308
•
1880
897
3,360
822
1881
672
616
4,932
10,147
6,268
Glendalough vein ranges east and west. The line in which it may be
traced is about half a mile, but to the west it probably ranges far up into the
Granite of the interior, while to the eastward it does not seem to extend
much into the mica Slate; not appearing, as might otherwise be expected,
on the precipices on the Glenasane side (Weaver).
The body of this vein is quartz, sometimes exhibiting sets of spherical
concretions, which often form the centre of a mass of galena. This quartz
rock abounds in cavities lined with quartz crystals, and more or less filled
with clay, iron ochre, and carbonate of lead. The vein likewise bears galena,
copper pyrites, sparry iron ore, and barytes. Blende and iron pyrites appear
occasionally. The lead ore produced 70 per cent. of metal, and the copper
ore from 10 to 15 per cent. The returns of lead ore from Glendalough were
for many years given with those of Luganure, and are included above, so
that it is not possible now to separate them.
Mr. Weaver gives a curious example illustrative of this mineral forma-
tion. He discovered near the surface a mass of lead ore nearly a ton in
*The production of silver and the value of the lead ore were not returned before 1874.
470
[BOOK II.
THE FORMATION OF DEPOSITS.
weight, and on blasting it he found fragments of mica Slate firmly imbedded
in the veinstone (Fig. 88).
Glenmalure.-The lead vein at Ballina-
finchogue, which forms an acute angle with
the valley, has been traced for a distance of
about 400 fathoms, and it is confined to alter-
nating beds of Granite and mica Slate. It
is inclined for more than 40 fathoms from
the surface to the southward, under an angle
of 80°, but for the remaining depth the dip is
northward at the same angle. The width
varies from 2 to 3 fathoms, and is composed
principally of quartz. The ore was origin-
ally obtained on the south side of the vein,
but it occurs on the north side, and also in
the centre; and when these three strings
coalesced, they formed considerable bodies
of ore. Quartz and galena are the principal
constituents, but the vein occasionally pro-
duced blende, copper pyrites, iron pyrites, and barytes. The annual pro-
duce of ore during a course of several years was, according to Mr. Weaver,
300 to 400 tons, yielding on the average 68 per cent. of lead. Several
other veins, but of comparatively small value, occur in this Granite range.
Fig. 88.
The Clay-Slate district of Wicklow, which is in any way metalliferous,
occupies but a small space. It is narrow, and does not extend in length more
than 10 miles, ranging from Croghan Kinshela on the south, through the
townlands of Knocknamohil and Ballymoneen, Ballymurtagh, Ballygahan
and Kilcashel, Cronebane and Tigrony, Kilmacow and Connoree towards the
west Aston range, on the north.
The discovery of gold in the Ballinvalley stream, at Croghan Kinshela, has
been already named. Mr. Weaver, who was appointed by the Government
as commissioner, and who is consequently the best authority on the subject,
stated that the gold "occurred in massy lumps, and in smaller pieces down
to the minutest grain. One piece weighed 22 ounces, another 18 ounces,
a third 9 ounces, and a fourth 7 ounces. The gold was found, accompanied
by other metallic substances, dispersed through a kind of stratum composed
of clay, sand, gravel, and fragments of rock covered by soil, which sometimes
attained to a very considerable depth, from 20 to 50 feet in the bed and bank
of the different streams. . . At Ballinvalley it was constantly found that
the gold was attended by magnetic ironstone, sometimes in masses of half a
hundredweight; by magnetic iron sand, by cubical and dodecahedral iron
pyrites; and in small pieces and grains, by specular iron ore, brown and red
ironstone, iron ochre, fragments of tinstone crystals, wolfram, grey ore of man-
ganese, pieces of quartz and chlorite, and sometimes fragments of quartz
crystals. I observed and collected also some specimens which show that the
gold, magnetic ironstone, and wolfram were frequently intermingled with
quartz, and I have also a few specimens which exhibit gold, not only incor-
porated with iron ochre, but ramifying in slight threads through wolfram.
CHAP. IV.]
THE GOLD OF CROGHAN KINSHELA.
471
Some of the gold occurred, though very rarely, crystallised in octahedrons,
and also in the elongated garnet dodecahedron."
There is but little doubt that the numerous gold plates found, especially
in the South of Ireland, were made from native Irish gold.*
Mr. Weaver asks: "What then is the primary source of these substances,
found detached in the beds and banks of the streams?" He answers his
question: "It is not improbable that they occur more or less scattered and
disseminated through the rocks of the mountain, although it must be acknow-
ledged that no discovery leading to this inference attended the researches of
the Government.
We may conceive that the gold and other metallic
substances had been detached from their native seat, and have been lodged
in their present position, in company with other alluvial materials, at the
time of the first formation of soil, and the retrocession of the ocean." The
total quantity of native gold collected by Government amounted to 944
ounces 4 dwts. and 15 grains, of which 58 ounces 16 dwts. I grain were
sold as specimens at £4 per ounce, amounting in value to £236 10s. 8d.
The aggregate value of the native and ingot gold was £3,675 75. 11d.
The discovery of native gold was not confined to Croghan Kinshela. Trials
were made at Croghan Moira, at Ballycreen, and at Fannanerin. Although
indications of gold were found, no quantity sufficient to pay the expenses
of the search was found.
Cronebane.—In this mine, about 1750, some peculiar indurated oxide of
iron was found in a metalliferous bed, in which was minutely disseminated
native silver. Assay gave about 30 grains of gold in the ounce of silver.
The auriferous silver was commonly sold for half a guinea the ounce.
The
rocks extending into Tigrony and Connorree have been perforated in various
directions by the subterraneous works for considerably more than 1,000
fathoms. The Clay-Slate and quartzose Clay-Slate contain subordinate beds,
which are usually called soft ground. Five such beds of soft ground have
been met with-one in Connorree, three in Cronebane, and one in Tigrony
The bed in Connorree contains a lode 4 feet thick, consisting of a fine-grained
intermixture of galena, antimony, and blende, with pyrites of copper, iron,
and arsenic. A similar lode occurs in the more southern bed in Cronebane.
The northern bed has yielded some thousand tons of black copper ore,
which in the greater depth passes into yellow copper ore. The third bed
in Cronebane has proved the most valuable, the greater part of its width
being filled with copper ore, chiefly black oxide. The bed of solid ore has
varied from 1 to 3 fathoms in breadth; the most productive parts of the bed
have in several instances yielded from 10 to 15 tons of merchantable ore
from the cubic fathom.
In the twelve years ending 1799 the mines of Cronebane yielded 7,533
tons of copper ore, which gave an average of 825 per cent. for copper. A
duty of 16s. 6d. British per ton existed up to this time on the importation of
Irish ores into Britain. In the next twelve years ending 1811 the produce
was 19,342 tons of ore, yielding of copper 1,046 tons. In the year 1808 the
ore raised was 2,576; after this, owing to the state of the copper trade, the ore
* “Notes on the various Discoveries of Gold Plates, chiefly in the South of Ireland." By T. Crofton
Croker, Esq. (From the “ Collectanea Antiqua,” vol. iii. London: 1854.)
472
[BOOK II.
THE FORMATION OF DEPOSITS.
raised at Cronebane did not exceed a few hundred tons. Sulphur was
extracted on the spot by roasting in kilns, and the waters flowing from the
mines held much copper in solution. This was separated by throwing scrap
iron into it. In Ballymurtagh extensive works were carried on, which is
thus described by the Rev. William Henry, who gives a good account of the
copper mines* in Wicklow, from which the following extracts are made :-
"The mine which was formerly wrought on, is that of Ballymurtagh, on
the south bank of the river. It yielded vast profits to the undertakers; but,
on account of some difference between Mr. Whalley and the company, it has
been disused for some years past. This is amply compensated by the far
richer mines of Crone-Bawn (in Latin Corona-Alba, now Cronebane) on the
north side of this river.
"Crone-Bawn is a hill of 2 miles in circumference, and, as near as I
can guess, about 1,000 feet in height, swelling regularly in the form of a
large inverted bowl. The bowels of this hill are, on all sides, full of rich
mines, as appears by the shafts which have been sunk in different parts
of it. But the principal works lie on the east side, about half-way up the
hill. Here I saw several shafts sunk from 50 to 70 fathoms deep.
In sinking these shafts the first mineral met with is an ironstone. Beneath
this they arrive at a lead ore which seems mixed with clay, yet yields a
large quantity of lead and some silver. Under this lies a rich rocky silver ore
which sparkles brightly, and yields 75 ounces of silver out of a ton of ore,
besides a great quantity of fine lead. . . . . There are 500 men employed in
these mines; their pay is 8d. a day. In order to carry off the water from the
mines there are levels carried a great way under ground from the lowest
part of the hill. Out of these levels issue large streams of water strongly
impregnated with copper." Dr. Henry then tells us, after describing the
WHIS
process of precipitation, "one ton of iron in bars
produces a ton and 19 cwt. of this copper mud
and rust. Each ton of this mud produces, when
smelted, 16 cwt. of the finest copper, which sells
at £10 the ton more than the copper which is made
of the ore."
The mines Tigrony and Lower Cronebane are
on the eastern side of the Ovoca. The beds of
decomposing and variously-coloured Slates, to-
gether with the sulphur course and the copper
lodes, are the continuation of the deposits of
Ballygahan, disturbed by a fault to the extent of
nearly 1,000 feet. During the large demand for
sulphur in 1841 and 1842 upwards of 2,000 tons of this ore was raised
per month. The annexed woodcut (Fig. 89) shows in the light band (2) the
iron pyrites-the narrow ribs with transverse lines are "strings" of slightly
cupreous iron pyrites.
Fig. 89.-Tigrony, Wicklow.
The copper lodes are very irregular, but more or less parallel to the
*"A Letter from the Rev. William Henry, D.D., to the Right Honorable the Lord Cadogan,
F.R.S., concerning the Copper Springs in the County of Wicklow, in Ireland." (" Philosophical Trans-
actions," vol. xlvii., for the years 1751 and 1752.)
CHAP. IV.]
CRONEBANE AND BALLYMURTAGH.
473
pyrites course; they commence almost immediately on its south wall, and are
sometimes seven in number, besides occasional intermediate ribs, within a
width of 20 fathoms, so that the ground is worked away in stopes of 14 or
15 feet wide, for considerable distances (Smyth).
In 1846 the work was concentrated upon the copper lodes, but subsequently
the pyrites ores have been largely extracted and sold from the Tigrony sett.
1872
1873
1874
•
1875
•
1876
1877
1878
1879
1880
1881
Copper Ore.
Tons. cwts.
•
22
88
63
4
•
Copper Precip.
Tons. cwts.
27
23
29
Pyrites.
Tons. cwts.
О
•
19,232 ΙΟ
16,318 10
9,486 O
6,588 O
56
4,937 O
•
59
•
70
ΙΟ
1,997 7
•
35
3
3,353 16
28
O
3,191
O
18
22
I I
O
5,735
29
O
6,790
Ballymurtagh mine has a large metalliferous deposit which dips into the
Slate at angles of 40° to 60° south-east, and consists, at a short depth from
the surface, of 12 feet in width of granular iron pyrites altogether free from
gangue or veinstone. This deposit is not bounded by distinct walls, but
has gradual interstratifications with the Clay-Slate. On the north, to the
distance of 100 fathoms, and on the south, for 20 fathoms, parallel veins of
copper ore have been met with. The iron pyrites has not been found in
available quantities at a greater depth than 100 fathoms; it appears to
become thinner at 80 fathoms from the surface, and then to unite with the
copper lodes on the south, forming together, at the 56-fathom level, a
"bunch" of copper ore 24 feet in width. This vein was, in one spot, by the
addition of numerous bands of greater or less thickness, increased to nearly
60 feet.*
The ore, which is the ordinary copper pyrites, is not gathered into a lode,
but it is interlaminated so delicately, as to appear often in fine films, forming
part of the adjoining rock. On the surface of the hill, about 120 fathoms to
the north of the principal vein, a course of iron pyrites was found of remark-
able size and solidity, averaging about 24 feet.
The produce of Ballymurtagh mine has been as follows in the years
named :-
Copper Ores.
Tons.
•
7,130
7,783
450
500+
Pyrites.
Tons..
9,575
9,582
. 21,861
Coppery Pyrites.t Copper Precip.
Tons.
Tons.
·
•
31,598
•
4,432
3,000
3,250
•
5
• 35,253
1844
1849
•
1856
•
1857
1858
1859
•
1860
•
1865
1870
1875
450
155
•
•
1880
•
1881
•
37,952
40,500
43,400
19,149
2,886
1,858
945
3,050
•
•
4,000
•
2,000
•
•
13
*This information is obtained from the excellent memoir "On the Mines of Wicklow and Wexford,"
by Warington W. Smyth, M.A., F.R.S., in the "Records of the School of Mines."
† Coppery pyrites contains from 35 to 40 per cent. of sulphur and 1 per cent. of copper. Some
samples contain as much as 3 per cent. of copper. Much of the Irish pyrites contains traces of gold,
which is separated at the works around Liverpool.
These were the quantities of copper ores sold at Swansea.
474
[BOOK II.
THE FORMATION OF DEPOSITS.
Mr. W. W. Smyth relates the following instance of a great fall of matter
in this mine:
"In 1835 a great fall of the solid iron pyrites occurred from the roof
of the 18-fathom level: a mass 30 fathoms long and 20 fathoms deep (at
an average of 10 feet wide, weighing nearly 30,000 tons) broke away and
crushed through all the levels to the bottom. The previous sounds of rending,
and the smell of sulphur, diffused by the friction, warned most of the men to
escape, and even the rats, which were living in great numbers underground,
fled to the surface. Eighteen men, however, who took refuge in a freshly
driven gallery, were immured at a great depth from the surface, and
after a couple of days passed in the most frightful anxiety, were extricated
by an orifice accidentally left, and found to extend through the heap of
ruins."
In Ballygahan mine, also one of the Ovoca mines, the general characters
of Ballymurtagh are repeated.
Shallee.-At Shallee a curious series of north and south lodes occur.
This point is 3 miles west of the calamine deposit, and upwards of 100 of these
small veins have been wrought, all of them open-cast, and none of them to a
greater depth than 7 fathoms. In some cases they are so close together that
the "country" left standing between them has no greater thickness than
3 feet. They occur mostly in divergent bunches, and are usually in the
vicinity of the Shallee fault, but, strangely enough, do not seem to run
into it, cross it, or be in any way connected with it. Their appearance
is quite exceptional, but they cannot be said to belong to the stockwerk
family. They are always found to the south of the fault in the Devonian
Sandstone.
Silvermines.-The Shallee fault is traceable for several miles, but its throw
is variable and not always easily estimated. Its valuable mineral contents are
lead ore (argentiferous), copper ore (chiefly pyritous), blende, calamine, and
sulphur. This arrangement of enumeration is the same as the progressive
occurrence of the various ores, as the fault is followed eastwards on its stroke
from Shallee to Silvermines. The blende mostly occurs scattered through the
pyritous rock in inconsiderable quantities, while the occurrence of the cala-
mine is still less frequent. The width of the mineral matter filling this fault
varies from a few feet to several fathoms. At a little to the north of the fault,
at Silvermines, a series of "old men's" workings have at some previous time
been carried on, and report states that a good deal of argentiferous galena
was extracted. Be this as it may, the slags found in heaps at this spot attest
to the carrying on of smelting operations. The mining works were scattered
over an area of several acres, and the whole surface of the ground for that
area is found covered with ochrey matter and stones of calamine, this mass.
being in some places a foot deep. It is worthy to note that a valuable
mineral, so extremely widespread and apparent, should have escaped obser-
vation for so many years; however, about the year 1859, samples were sent to
Professor Apjohn, when the mineral was determined to be an earthy car-
bonate of zinc, and explorations were at once instituted. The result of these
have shown a most extensive bed of zinc ore, varying from 10 to 60 feet thick,
and covering a known area of several acres. It seems to occur as an inter-

CHAP. IV.]
MINERAL VEINS IN CORK COUNTY.
475
foliation between the true Limestone beds and the dolomite, while it dips
north with the strata at an angle of from 20° to 30°.
a....
Plan
Glandore Mineral Channel, County Cork.*-The original fissure was filled
with conglomerate stuff made up of the country rocks. The second fissure,
which ran very regular, that is, more or less parallel to the walls of the first,
was filled with iron ore. There were
strong reasons for supposing that the
iron ore was only the back, or gossan,
of a copper ore. If such was the case,
the fissure must have been first filled
with copper ore, while the iron ores
were the result of chemical changes.
The third-a very irregular fissure-
sometimes running with the iron ore,
at other times across it, or leaving it
altogether, and being in the conglo-
merate, was filled as far as can be seen
with manganese ore. This channel
was of no great width, but others are
much more considerable, such as
those at Ovoca, County Wicklow.
In these wide channels of faulted rock
a newer fissure may form, or two or
more quite independent fissures, as
shown in the diagrammatic plan, and
section, Fig. 90.
North and south of the fault are
the country rocks, which strike and
dip independent of it. In the channel a
is "the man's lode," supposed to fill a
fissure second in age, while coincid-
ing with the structure of what Mr.
Kinahan calls his third system, which
consists of copper ore lodes.
dede d
b
d
a
Section
Fig. 90.-a, first fissure-channel of Fault Rock; b,
main lode, second fissure; c, yellow copper ore
lodes, third fissure; d, Country Rock; e, fel-
stone in Country Rock; f, fault in Country
Rock that does not effect the channel of Fault
Rock.
Even mineral lodes may be made
up
of fissures within fissures, some of these being nearer than others, and ap-
pear to have filled cracks which may probably have been produced by shrink-
age. Mr. Kinahan mentions another class of faults, consisting of masses of the
native rocks, ruptured and displaced, but not entirely broken up.
In places
in County Wexford, in faults of this class, there will be found unbroken por-
tions of beds of Limestone, and other rocks, running continuous for many
yards, some being of such length that they may easily be supposed to
belong to undisturbed strata; but that they are in wide faults is proved
by their running transverse to the strike of the rocks at both sides of the
fault.
In the preceding pages several examples of the characteristic features of
*Notes on Fault-Rock." By G. Henry Kinahan, M.R.I.A. ("Transactions of the Manchester
Geological Society," vol. xvii. 1882-83.)
476
[BOOK II.
THE FORMATION OF DEPOSITS.
lodes, or veins, have been given. There are still some conditions in connec-
tion with the filling of lodes, and the dissemination of minerals, which appear
to require additional notice.
Parts of many lodes consist of a succession of plates of mineral sub-
stances, varying much in their continuity, and to a certain extent parallel
to the sides of the fissures, between the walls of which they are included.
These vertical plates, which vary from a few lines to many inches in
thickness, are known to the miners in Gwennap, and in other parts of
Cornwall, as combs, and a lode is said to be a comby lode, when composed of
such vertical plates.
Sir Henry de la Beche has paid considerable attention to lodes of this
character, and he makes some most pertinent remarks on the formations of
the combs. He especially refers to a drawing of a lode in Wheal Catherine
(Fig. 91) mine on Carn Brea, near Redruth: “All the combs, or plates,” he
says," have the points turned inwards, and all are readily separable from each
I 2 3
3
4 5 6
4
other by a moderate blow along the surfaces
-I, 2, 3, 4, 5, 6, are ochreous indurated
clayey substances which separate the combs
a b c d e f from each other. From all we
know respecting the filling of cracks by cry-
stalline substances, deposited from solutions
in them, we should conclude that the breadth
of each comb constituted the whole width of
the fissure, at the time of the substances of
which the comb is composed were crystallised
upon both walls of the fissure as bases, so that
the crystallization gradually met in the centre.
If this be correct, we should have six con-
secutive openings of the fissure for the contents
of the lode here represented, so that I and 6
constituted the walls of the lode, or the sides of the fissure, when the combs
above noticed were all formed.”
α b с
d
f
Fig. 91.-A Comby Lode.
This is an ingenious way of accounting for a remarkable example of this
comby structure. The principal difficulty is to explain the enormous force
required to open such a rock fissure. We know that the crystalline force
exerts an immense mechanical pressure, but it is doubtful if the force is equal
to the movement of a solid rock in its natural bed, surrounded on every side
with the most coherent masses. It must be confessed that it is not easy to
suggest any other method. We may, indeed, suppose that the crystals first
formed upon the walls-the sides of the fissure, and that the cavity was
filled with clayey matter, upon which the second layer of crystals began
to form and gradually dovetailed into the first layer. The clay wall would
afterwards be removed by the action of water which would increase in
power, as the progressing crystallization rendered the passage narrower and
narrower.
Sir Henry de la Beche gives a second example from a lode in Wheal
Julia, near Binner Downs, Crowan. "In this" (Fig. 92), he says, "we per-
ceive more irregularity than in the preceding figure, and in the comb e we
CHAP. IV.]
STRUCTURE OF COMBY LODES.
477
see that crystals of sulphide of zinc, intermingled with bi-sulphide of copper,
were formed on each side before the quartz was deposited, and such in
crystallization is the centre of the comb. The vug or cavity at g shows
that the crystallization had not filled up the space in that direction, and the
group of pointed crystals in it exhibits the general appearance of those parts
of the fissure where the crystallization had not met from the sides, and by
interlocking filled up the cavity."
9
The plates thus formed are actually separated from each other by a thin
deposit of clay. After the deposition of the metallic ore there appears to
have been a period of repose, during which the earthy matters have sub-
sided from the water flowing slowly through the fissure. It then, however,
frequently happens that a different ore is
deposited from that which first fixed itself
against the walls of the lode. Perhaps the
first deposit may have been iron pyrites, then
a thin sheet of clayey matter. It not unfre-
quently happens that the succeeding plate is
of copper ore. This goes on for some time,
and on both sides of the lode, and then again,
owing to some change, which is due to con-
ditions we are unable to trace, another period
of repose, or at all events a change of con-
dition, takes place, and sulphide of zinc
(blende) is deposited, or sometimes some
earthy minerals take the place of the metal-
liferous ones. This goes on slowly, each side
of the lode usually exhibiting the same forma-
tion, until the middle of the lode is reached.
It then becomes evident that a current of
water has continued its steady flow, and when
the lode is opened, streams of very clear water
usually flow out, and clayey matter, with fre-
quently crystals of quartz, is found surround-
ing the vacant spaces.
b c d f e
Fig. 92.
h
a Bisulphuret of copper and sul-
phide of zinc.
b. Comb of quartz.
c. Wall of indurated argillaceous
matter.
d. Comb of quartz.
e. Large comb of quartz, with
blende and yellow copper ore,
ff, on both sides.
g.
Vug, or cavity in another comb
of quartz.
h.
More solid comb of quartz.
It is scarcely necessary to remark that the
"mass of indurated argillaceous matter"
appears to furnish a base, upon which a crop of crystals might form and
produce the required comby structure.
"A close inspection of the quartz crystals forming combs, by interlocking
towards their central parts, often shows the gradual increase the crystals
have received in the direction of the axes of the prisms, and sometimes small
sprigs of copper ore or blende may be seen entangled among them, in lines
corresponding with surfaces which existed during the formation of the comb,
as if, while the crystallization of the quartz was effected, the silicious solution
sometimes contained the elements of bi-sulphide of copper, and was fre-
quently without them, or, if it always contained them, that conditions were
often unfavourable for their deposition on the sides of the cavity holding the
solution" (De la Beche).

478
[BOOK II.
THE FORMATION OF DEPOSITS.
Fig. 93 is another example of a comby lode from Carn Marth. In this
drawing the "combs" are slightly exaggerated-although in position, &c.,
strictly true-for the purpose of showing more prominently the peculiar
characteristics of this description of lode. The several layers are distinctly
marked. The student may, therefore, readily note the order in which each
layer was produced. In this example it would appear as if the mass of copper
ore marked E had been an opening which had been filled in, at a later period
than any of the other bands. There is a certain inequality in the number of
layers on either side, counting from the walls of the lode, which will scarcely
agree with the explanation given by De la Beche.
The layers composing a metalliferous lode are sometimes composed of
BDBEBF
K
abcae c
acba
d
DBE BFBGBKA
Fig. 93.-Comby Lode from Carn Marth.
A A. Walls of lode. Granite.
B B. Clay partings.
C. Quartz and purple fluor.
D. Quartz with yellow copper ore.
Quartz-dark shade copper ore.
F. Quartz and purple fluor.
G. Quartz.
H H. Quartz, with a little copper ore.
KK. "Vugs"-cavities.
Black spots and patches are copper
ore.
-
Fig. 94. Crystallised Mineral
Lode.
a a, on each side of the lode, is a
band of iron pyrites.
bb represents plates of quartz, upon
the iron pyrites.
cc are copper pyrites-the yellow
sulphide of copper and iron.
dd are bands of quartz and fluor-spar.
ee are bands of quartz, containing
veins of copper ore.
ff are crystalline layers of quartz,
with strings of copper ore.
different substances, as in the other woodcut (Fig. 94). Unless the crystal-
lization in the lode shows that the resulting solid ore has been formed
by additions from the sides inwards, we know not what explanation can be
given of the conditions. We cannot be certain that all such lodes have
been produced by successive openings. Without doubt much difficulty
surrounds this question, which can only be solved by a most careful exami-
nation of a considerable number of analogous phenomena in lodes, formed
in rocks of varied character, and passing through dissimilar strata. The
uniformity of this crystalline lode is remarkable.
Werner notices a specimen from Segen-Gottes at Gersdorf, in which,
reckoning from the middle-composed of two kinds of calcareous spar-
thirteen layers of different minerals are arranged in the same order on each
side of the vein. In the southern vein, the two beds which are next the rock
CHAP. IV.]
FLUOR-SPARS OF DERBYSHIRE.
479
are quartz; next to this on each side is sulphide of zinc, mixed with iron
pyrites. This is followed by sulphide of lead, carbonate of iron, another
layer of galena, then carbonate of iron, again galena, carbonate of silver, red
silver ore and sulphide of silver. The most recent portion, or the central
part, being calcareous spar.
M. Fournet* gives the following example of a lode varying with the
changes in the adjoining rock: The Winzel lode, at Furstenberg, runs nearly
vertical from north to south across many beds of gneiss, about 60 feet thick,
dipping east. Each of these beds forms a distinct variety of rock. The
first is very micaceous; the second passes into argillaceous Slate; the third
is hornblendic; and, in the fourth, scarcely any mica can be detected.
This lode is heaved in depth to the westward by several cross courses, and
it was between two of these cross courses, distant from each other about
40 fathoms, that it exhibited those riches for which it was celebrated. In
the first bed of gneiss, the lode merely formed a nearly imperceptible string
of clay; in the second it suddenly acquired a thickness of from 12 to 18
inches, and was composed of sulphate of barytes, antimonial silver, red
silver, and argentiferous grey copper ore. The antimonial silver was always
found in large masses. In the third bed, the thickness of the lode was
preserved, and the sulphate of barytes continued in it, but the silver ores.
disappeared, and a little sulphide of lead was the only ore found. In the
fourth bed the silver ores became as abundant as in the second; but they
gradually disappeared in depths and were replaced by selenite, a little
sulphide of lead, and some traces of native sulphur. We have nothing
in this country which presents such striking changes as those described
by Fournet; but we have many examples of a similar description.
Fluor-spars, or crystallised fluates of lime, are found in great beauty
and variety in the mines of Derbyshire. The most noted mines for this
interesting mineral are:—
Ashover
Bonsal
•
•
Bradwell
Castleton
Crich
Cromford
Matlock
Overton
•
Roston
•
Fallhill and Westedge mines.
Ball-eye mine.
Picture End, Smalldale Lead and Tanner's Venture.
Cliff-side, Miller's Pipe, Odesi, Old Tor, and Water-hull.
Crich-cliff.
Ash-cross and Gang.
Dimple, Knowle's, and Seven Rakes.
Gregory.
Birchwood Park
Wirksworth
North Cliff, Orchard, Ratchwood, &c.
At several of the fashionable places in Derbyshire fluor-spar ornaments
are manufactured on a large scale, especially from the purple variety. There
is also a consumption of the yellow and inferior kinds of this spar, derived
principally from the Crich mines, as a flux for melting lead and copper ores.
The annexed woodcut, of a Fluor-spar lode, is instructive. Fluoric acid is
one of the so-called elementary bodies. In many respects it resembles chlo-
rine. Indeed it forms one of a group which appears to have much in common,
including bromine and iodine. Fluoric acid-the combination of hydrogen
with fluorine-unites with lime with much avidity, forming a fluate of that
* Fournet, "Études sur les Dépôts Métallifères." (D'Aubuisson's "Traité de Géognosie,” 2nd book,
vol. iii.)
480
[BOOK II.
THE FORMATION OF DEPOSITS
earth. It also readily unites with silica, as may be proved by the way in
which it etches glass. There is no doubt that fluorine plays some very
important part in the chemistry of nature. An interesting field of inquiry
lies almost untouched for the investigation of the chemist. In studying the
phenomena of mineral lodes, we constantly discover evidences of the action
of hydrofluoric acid; but we have not yet isolated fluorine, or determined the
لله
Fig. 95.
I
2
2
I
1. Limestone. 2 2. Blue fluor-spar. 3. Mixture of clay, yellow fluor-spar, and sulphate of
barytes, with nodules of "Blue John."
variety of combinations with earths and metals into which this important
element enters.
"Blue John" is a name given to a dark purple concretionary variety of
fluor-spar (fluate of lime). Fig. 95 is a section of a part of one of the veins.
containing this beautiful mineral. They are generally irregular flattened
pipes, running almost horizontal, then bending sharply up or down across
the bedding. At the point where this drawing was taken the lode was
nearly flat. Its upper and under surface was lined with coatings of blue
fluor-spar, and the space between these was filled in by a mixture of
reddish-brown clay with yellow fluor-spar and nodular sulphate of baryta.
In this were scattered, here and there, concretions of the Blue John arranged
in concentric layers of different tints and in radiated masses. Nodules of
Blue John are also found in the solid Limestone around the lodes.
An interesting variety of fluor-spars are found in Allendale, in Weardale,
and in Alston Moor. Crystals of considerable difference of form are pro-
duced in the different lead mines: cubical crystals, with the edges sometimes
bevelled, octohedral, polygonal, and very irregular. The colours are very
numerous: red, green, blue, yellow, purple, violet, colourless, and all gra-
dations, from very pale to almost black; often of a drab surface, composed
of different minute crystals, and not unfrequently speckled with marcasite,
very commonly found mixed with lead ore, spar, &c., sometimes studded
with brilliant quartz crystals and with finely crystallised galena. The
fluorescence of this spar, and similar optical phenomena, seen in other
substances, have been most carefully investigated, and fully described by
Professor Stokes, in the "Transactions of the Royal Society."
In connection with the Derbyshire lead lodes, and their relation to the
Limestone and the Toadstone, several important particulars relative to the lodes
CHAP. IV.]
BARYTES MINES IN UNITED KINGDOM.
481
on Crich Hill have been furnished by Mr. E. M. Wass, of the Lea Lead
Works, Matlock.
"In the 'Pearson's Venture,' situated on the west side of Crich Hill, the
Toadstone was reached at a depth of about 80 fathoms; its thickness was
II fathoms. This was a most productive mine, both above and below the
Toadstone, but at a depth of 115 fathoms the vein became contracted and
poor, and this ground being heavily watered was abandoned.
"The 'Bacchus pipe' is also on the west side of the hill; there the Toad-
stone was found after sinking 75 fathoms, and its thickness ascertained to be
20 fathoms.
"At the 'Glory mine,' north of Crich Stand, a much wrought and in past
years very remunerative mine, the Toadstone was discovered 30 fathoms from
the surface, and found to be 9 fathoms thick. The lowest workings at this
mine were 135 fathoms from day; the veins, however, diminished so
materially in strength and productiveness the lower they were followed as to
discourage trial requiring pumping machinery.
"The 'Old End mine,' on the eastern slope of the hill and north of Crich
Stand, has been explored to a greater depth than any of its neighbours. The
Toadstone there was arrived at in 50 fathoms; the deepest workings went
down about 152 fathoms."
In these mines all the lead lodes became poorer the lower they were
followed; and a glance at the map of the Geological Survey will show that
lodes are more numerous in the upper than in the lower beds of the Lime-
stone. Mr. Wass says: "My own experience certainly confirms what has
been frequently advanced, namely, that as a rule our veins are stronger and
more productive in the upper than in the lower parts of the Limestone." We
are not in possession of facts enough to justify us in making any sweeping
generalization on this subject, but all we do know seems to point to a falling
off of the contents of the lodes as soon as the lower Limestones are entered.
Barytes Mines.—Barytes enters largely into the component parts of the
lead lodes of Derbyshire. This earth is known as the crystallised sulphate of
barytes, as Terra Ponderosa, as heavy spar, as cauk, or tush (Dr. Woodward,
in his "Method of Fossils," terms this mineral croyl stone). Barytes occurs
also in considerable quantities in Shropshire. In 1881, Snaibeach produced
559 tons; Weston, 523 tons; and Wotherton, 2,195 tons. In Northumber-
land, in the same year, Fallowfield produced 2,906 tons, and Settlingstones,
2,512 tons. Raygill, in Yorkshire, produced 2,017 tons. Derbyshire, from
44 lead mines, gave 5,140 tons. Ireland, from Duneen Bay, gave 3,786 tons.
The total production of Barytes-sulphate and carbonate—in the United
Kingdom in 1881, being 21,313 tons, of the value of £23,894.
The following remarks on the formation of barytes in the Dufton mines
are by Mr. William Wallace, who was for a considerable time the manager
of them: “The sulphate of barytes is the principal mineral found in Dufton-
Fell mine. It is deposited chiefly in flats in the Limestone strata, mixed
with lead ore. The range of this mineral, in depth from the surface, is,
however, very limited; the most extensive deposits in the flats exists near
the surface; and are chiefly restricted to the Tynebottom and Jew Lime-
stones. The quantity of barytes deposited in the Tynebottom Limestone,
I I
482
[BOOK II.
THE FORMATION OF DEPOSITS.
from its line of outcropping to the cross vein, is very large. The Lime-
stone has been removed to a width of 180 feet or more, and the space filled
with this mineral and lead ore. The process of either removing and sub-
stituting Limestone and barytes was probably very slowly effected. If the
former was the case, both processes must have been going on at the same
time, as no large spaces could have remained unfilled with barytes, after the
Limestone was removed; for the bed of soft shale which rests upon it
would have fallen into them. The space originally filled with Limestone
has, however, in some places, contracted a little; for the shale had given
way, forming horizontal cracks or openings, seldom more in width than the
thickness of a penny-piece. These openings are all filled with lead ore.
What is also remarkable is that the smallest particle of barytes mixed with
the thin sheets of lead ore could not be detected-it was simply pure lead
ore seamed into pure unchanged shale. This occurred on the south side of
Hard Ark vein, where not less than 54 feet in width of Limestone from the
vein has been removed, and all the space, except the small contraction
occasioned by the formation of the spaces, in the bed of shale, filled with
barytes and lead ore. An instance of shale having fallen into the open
space during the formation of flats came under observation in the Tyne-
bottom mines in Alston Moor. In these mines the plate or shale partakes
more of the character of hard rock than it usually does, and is of a peculiarly
mottled grey colour. At one place it was found in irregular masses filling
up the space which had been occupied by Limestone, and all the interstices
between the broken lumps were filled with carbonate of lime and lead ore.”
The extent of barytes in the Tynebottom Limestone is greater than that
of lead ore. At the extreme east end of the mine the quantity of barytes
deposited in the Tynebottom Limestone, in connection with Hard Ark
and Dobson's veins, though large, yet only forms a small proportion of the
quantity deposited in connection with Barrow's vein near the outcrop. A
similar fact is connected with the deposit of barytes in the Jew Limestone.
It is also only in connection with the richest deposits of lead that the most
transparent crystals of barytes are formed. Farther east, and towards the
limits of the lead ore deposits, the crystals of barytes are perfect in form but
invariably opaque.
Westgarth Forster says he "has seen cauk spar of a dead white, but com-
monly it is of a yellowish or a reddish white, or of a flesh-colour, sometimes
crystallised and transparent as at Dufton-Fell in the county of Westmoreland.”
In the Limestones below the Jew, and near the surface, only very small
quantities of lead and barytes have been deposited. In the Smiddy Lime-
stone, Barrow's vein contains no barytes and very little lead ore. The vein
is filled with ferruginous rubbish. Directly below the vast deposit of barytes
and lead in the Tynebottom, Barrow's vein contained no barytes or lead.
The Limestone on each side of the vein was carbonised or crystallised into a
substance almost as hard as adamant. The making of an ordinary rise, in
a portion of the ground, cost £45 per fathom. No sparry substance was
found in the vein. The deposit of barytes and lead in the Melmerby Scar
Limestone is limited to a small portion of Barrow's vein near the surface
and close on the east side of the Pennine Fault. Through the whole extent
CHAP. IV.]
GENERAL RÉSUMÊ OF HYPOTHESES.
483
of this ground no flats are formed, nor are any lead or barytes found in the
vein, which after the barytes disappears is simply filled with clay and
rubbish.
There is a vein in Welhope, in the county of Northumberland, containing
the common cauk spar, or sulphate of barytes, in the upper beds, which
changed its matrix in the Great Limestone, and contained aerated or car-
bonated barytes. It lies mostly in cavities, or shakes of the vein, in round
balls, and when broke, it is striated as diverging from the centre (Westgarth
Forster).
In Robinson's Limestone, which may be considered as the upper part of
the Melmerby Scar, and also in the Smiddy Limestone, Dobson's veins
could not be identified. They existed simply as very small cracks or fissures
in the rocks which had sustained no chemical change, though only a very
short distance farther east the space which the Jew Limestone lead occupied
between the two veins was entirely filled with barytes and lead ore.
The Hard Ark vein ceases to exist on the east side of the outcropping of the
Tynebottom Limestone. White Rake and Barrow's veins are the only veins
of any magnitude which extend to the Pennine Fault. Extensive flats have
not been formed in the Limestone sides of White Rake vein. The lead ore
and barytes, of which latter substance the vein contains a great deal, is,
however, only small, when compared with the deposits of this substance in
flats on the sides of Barrow's vein. The old works in White Rake vein are
in a great measure closed; in consequence I have had few opportunities of
making personal observations.
General Résumé of the Subject.-Mr. John Taylor-to whom mining is
under a great debt for the introduction of a superior system of working
mines, and for numerous improvements in the machinery employed-in a
Report on Mineral Veins * remarks: "Kirwan supports the doctrine that
some veins were originally open, as appears from the rounded stones and
petrifactions found in them. Thus in the Granitic mountain of Pangel, in
Silesia, there is a vein filled with globular basalt. So also in veins of Wacken,
in Joachimstahl, in Bohemia, trees and branches have been found. But he
deems it improbable that all veins were originally open to day, and filled
from above. He inclines to the theory of veins being filled by the perco-
lation of solutions of the metals and earths."
Mr. J. Taylor, in concluding his report, carefully summarises all the
hypotheses which have been from time to time promulgated. His remarks
are much to the purpose:
"The greatest controversy relates as to the mode in which veins have
filled. Werner, and the mining authors on whom he relies, drew their infer-
ences as to deposits from metalliferous veins. Hutton, Playfair, and others
regarded chiefly those of a trapean character. That certain veins have been
filled by injection from below, and with matter in igneous fusion, seems to
be rendered certain by evidence, which is clearer than most we possess on
such subjects, and must be admitted at once. Thus when we see a trap dyke
* "Report on the State of Knowledge respecting Mineral Veins." By John Taylor, F.R.S., Trea-
surer of the British Association for the Advancement of Science. ("Transactions of the British Associa-
tion," Cambridge, 1833.)
II 2
484
[BOOK II.
THE FORMATION OF DEPOSITS.
traversing a bed of coal, and charring the combustible matter, and affecting
the rock itself with visible effects of great heat, we must admit the cause
assigned. In answer to this the question is asked, why, for instance, if the
ores were forced from below, did the power which injected them just limit
itself to raising them within a short distance of the surface, for where shall
we find an instance of their being protruded above it? The quartz reefs,
which may be quoted as examples of mineral veins-for essentially they are
such—are examples of the very protrusion which is supposed not to exist. If
the matter enriching our lodes had been derived from below we should expect,
by a nearer approach to the centre of the earth, to find metallic riches more
abundant. The hypothesis of filling up veins-fissures-by precipitation, is
supposed to be defective in not being able to show what menstruum could
render such substances soluble in water. This inquiry has been already
answered by the facts that the waters of the ocean and mineral springs do
hold most of the matters found in mineral lodes in solution.”
It has been urged that the supposition is absurd, that water cannot arrange
its deposits in places highly inclined. We do know that silica is soluble in
water, and that crystals of that mineral do arrange themselves on the sides of
vessels in planes highly inclined. Stalactites of chalcedony are by no means
uncommon. In the cliffs at Perranporth is a vein of chalcedonic quartz, at
least a yard wide, which is made up of vertical bands. Again, we have
examples, as have been already shown, of quartz veins, with iron pyrites
and copper ore in veins which are very slightly removed from the vertical.
Those who object to the idea that veins may be filled by matter in a state
of igneous fusion, as well as those who find great difficulty in supposing that
water was an active agent in the formation of lodes, are driven to adopt the
view that metallic vapours, and exhalations from vast depths, have been con-
densed on the sides of cracks, and this view is borne out to a considerable
extent by the vents through which, in California, the hot waters, steam, and
vapours escape. The hypothesis of filling up by sublimation would seem to
require that the deepest portions of the veins should be the richest. Shallow
as mine workings have been, there is every appearance of their having gone
below the richest deposits of the metals. "It is impossible," says Mr.
Taylor, "to say that greater deposits may not exist still lower down; and
though veins have not been traced to their termination, they have in many
instances been pursued until the indications of metallic produce have become
faint and hopeless."
The relation which the contents of a vein bears to the nature of the rock
has been already dwelt on, but the following general statement by Mr. J.
Taylor cannot fail of being acceptable: "In the older rocks, we see the
same vein intersecting Granite and Slate; it is itself continuous, and there is
no doubt of its identity, and yet the contents of the part enclosed by the one
rock shall differ very much from that which is found in the other. In Corn-
wall a vein that has been productive of copper ore in the Clay-Slate, passing
into the Granite, becomes richer, or what is more remarkable, furnishes ores
of the same metal differently mineralised. Veins in some cases cut through
the Elvan courses, as well as the Clay-Slate enclosing these porphyries; the
ores are rich and abundant in the latter, in other instances they fail altogether.
CHAP. IV.]
RELATION OF VEINS AND ROCKS.
485
Less striking differences in the structure of the rock affect the contents of
the veins. The miners often rely upon a change of ground as an assurance of
improved conditions in the lode itself. In the lead mines of the northern
counties this is remarkably shown. Indications of this have already been
noticed, but a statement made by Westgarth Forster may with advantage be
repeated: "The lead-producing rocks occupy a thickness of about 280 yards.
Nine of these beds are of Limestone and eighteen are of silicious Sandstone,
locally termed Gritstone, and the remainder are black shale 'plate' with
thin beds of coal. The fissures forming the lead veins are common to all, but
lead ore is only found in particular beds. Where the lode passes through the
black shale little or no lead ore is found. In the Sandstone the veins are more
productive, but it is only in one of the beds of Limestone that lead ore is found
in large quantities." Mr. John Taylor concludes a report by stating: "That
metallic ores are found to repose in rocks which seem congenial to them,
and that their combinations are modified by changes in the rocks, will not,
I think, be disputed by practical miners, or by those who have most narrowly
searched into the hidden recesses of the Earth.”*
Quartz occurs in nearly all mineral veins; it may be distinguished from
calcareous spar by its crystallization. Several species of this kind of spar are
found, sometimes cubical, and often tabulated. Much shoots into prismatic
crystals, so pure and pellucid as to resemble the diamond, differing from that
gem, however, by its hardness, and its less refrangibility. Quartz is often
found in Elvan courses in Cornwall in double-pointed crystals, indeed they
may be regarded as a characteristic of these porphyritic dykes. These crystals
are found abundantly in the neighbourhood of Wheal Coates in St. Agnes,
and also in the Elvan, on Roborough Down, near Tavistock. Mr. Prideaux†
described their occurrence in a bed of porphyry: "Running from nearly
opposite Hoo Meavy to Bickham is a bed of singular porphyry, with no
defined dip, boulders of which are strewed about the Down so extensively, as
to have acquired the name of Roborough Down stone. It is almost white
on fresh fracture, becoming brown by the weather, and is full of small cavities.
* To illustrate the comparative bearing of the different beds in the manor of Alston, Mr. Thomas
Dickenson, Moor-Master for Greenwich Hospital, got out for Mr. John Taylor an exact account of the
ore produced from each bed in all the mines of the manor in 1822 :-
LIMESTONE BEDS.
GRITSTONE BEDS.
f Great Limestone
Little Limestone
Four-fathom Limestone
Scar Limestone
Tyne-bottom Limestone.
Higher Slate sill
Lower Slate sill
Firestone
Pattinson's sill
High coal sill
Low coal sill
Tuft
Quarry hazel
•
Nattrass gole hazel
Six-fathom hazel
Slaty hazel
•
•
Hazel under Scar Limestone.
•
Whole produce of the manor
+ "Transactions of the Plymouth Institution," vol. i. p. 30.
•
20,827 bings of 8 cwts. each.
287
91
90
363
21,688 bings.
107
289
262
259
327
•
154
306
44
2I
576
18
2
2,365 bings.
24,053 bings.
486
[BOOK II.
THE FORMATION OF DEPOSITS.
It is thinly disseminated with minute crystals of translucent quartz, and
the cavities which appear to be cubical when regularly formed, contain in
some instances remains of the matter with which they were irregularly filled.
Quartz is very generally found lining the hollow spaces (vughs) in lodes.
Sometimes the lodes consist entirely of quartz, forming the lodes, or in
layers of white crystalline quartz, abounding in cavities, often lined in the
most beautiful manner with crystals of silica, and frequently enclosing
broken fragments of the Slate rock. These pieces of Slate are generally
sharply defined, and are commonly very uniform in their positions,
frequently showing, however, a flinty character. There is a striking
difference between the nature of the crystalline quartz, in the vicinity of
fossiliferous rocks, and that which occurs near Granite. In the former the
vughs are very numerous, and usually small, and the quartz crystals with
which they are encrusted are very small and of a snowy whiteness. In the
latter the cavities are less frequent, of a different size, and have often a high
degree of transparency."
These vughs are often of great size. In Dolcoath mine, one was broken
into which was from 18 to 20 fathoms in length, 3 fathoms high, and from
4 to 9 feet wide. This occurred in the main lode, and was, indeed, a series
of small caverns opening one into the other. It was filled with vesicular
carbonate of iron with quartz crystals.*
Between the 110 and 120 fathom level in the Consolidated mines, Gwennap,
a very extensive "vugh" was discovered in 1835. It was nearly 40 fathoms
in length and from 1 to 2 fathoms high. The direction was nearly horizontal,
the lode both above and below producing good ore.†
Many of the cross veins (cross courses) are mainly made up of quartzose
varieties of the contiguous lodes, but they differ from the lodes in being
seldom metalliferous, and in the crystalline character of the quartz. The
jointed structure is another characteristic of the cross veins, but this is confined
to their quartzose portions alone. They also exhibit an irregular crystalline
arrangement of the quartz, the axes of the crystals being disposed across the vein.
Mr. W. J. Henwood remarks: "This crystallization seldom or never presents
a symmetrical form, but the whole consists of a congeries of small crystallised
masses bounded by faces, which are disposed at right angles to the direction
of the vein; they intersect in almost every imaginable manner."
Westgarth Forster says: "Most of the mineral spars are frequently found
shot into prismatic, cubic, hexagonal, or other figures. These figured crystals
are generally transparent and very beautiful. It is a great curiosity to behold
the inside of some of the large cavities in which they are formed. Those
caverns, lined with crystals, are frequently met with in hard mineral veins,
and they are generally called by the miners shakes, lochs, or loch-holes."
continuation Mr. W. Forster says: "The magnitude of those caverns is
generally in some proportion to the capacity of the veins in which they are
found, and the insides of them frequently exhibit all the variety, beauty, and
splendour of the most curious grotto work.
"There is, commonly, a hard, concreted, stony crust, called druse or riders
*Mr. Rule," Cornwall Geological Transactions," vol. i. p. 25.
† Mr. Burr, The Mining Review, July, 1835.
•
CHAP. IV.]
THE VAN MINE, MONTGOMERYSHIRE
487
by the Alston Moor and Allendale miners, adhering to the inside of the
cavity, out of which, as out of a rock, an innumerable multitude of short
prismatical crystals are shot, which sparkle like a thousand diamonds with
the candle, or when brought to the sun. Between these clusters of mock
diamonds, and sticking to them promiscuously, there are often lead ore,
black jack, pyrites or sulphur, and spar, shot also into prismatic, cubic, or
other figures, which grow one upon another, and are, as. it were, piles upon
one another. The whole inside of the cavern is sometimes most magnificently
adorned with the most wildly grotesque figures, which grow upon and branch
out of one another in a manner not to be described, and with all the gay and
splendid colours of polished gold, of the rainbow, and of the peacock's tail,
and all these blended together, and the masses reflecting all the beauty of
such an assemblage of gaudy colours. But it may be remarked that these
caverns are never so magnificent and glorious as when there is less or more
of yellow copper ore, or of pyrites, or black jack, in them, as these ores are
found to produce in hard veins the most beautiful colours in the world. Many
eminent instances, in proof of this assertion, are to be seen in the lead
mines at Allenheads and Coal-Cleagh, in Northumberland, and Nenthead, in
Cumberland.
"Quartz does not rise in blocks (in this country) or large regular masses
. . . . it being full of cracks so as to break into small irregular masses, with
various sharp angles, and it is so hard as to waste the tools more than any
other stone. Where quartz and quartzy spar prevail, the veins are hard to
work, and it is no easy matter to separate the ore from the quartz in dressing,
being so hard that it requires much labour to break the quartz with ore small
enough; and it is also so heavy that it does not easily separate.
The Van mine,† which has been one of the most productive lead mines in
the British Isles, lies about 2 miles north-north-west of Llanidloes, in Mont-
gomeryshire. The lode is well described by Dr. C. Le Neve Foster, who
loses no opportunity-afforded by his position as Inspector of Metalliferous
Mines—of inquiring into the various phenomena which are constantly brought
under his notice.
This vein is said to have been traced along the strike for a distance of
9 miles, but this is doubtful. The lode at the Van mine runs in a direction
of about east 26° north (true), and dips south on an average about 74°, though
sometimes the dip is not more than 67°. The width of the lode is generally
several fathoms, and the portion producing ore is 48 feet wide. The filling of
the fissure may be regarded as composed of three distinct parts on the south
side, the flucan, or soft lode, which is a mass of clay and broken-up Slate,
varying from 12 to 24 feet in width. It appears evident that this great fissure
or gash was for a considerable period the channel of a deep torrent, and that
during this flow the Slate rock was softened, broken down, and for some depth
converted into clay. This is proved from the fact mentioned by Dr. Le Neve
*Westgarth Forster's "Treatise on a Section of the Strata," p. 219. 1821.
† Mr. T. F. Evans and Captain Williams both say that the name is derived from a neighbouring hill,
"y. Fan"—that is, the place, or the spot. Captain Williams informed the author, when he visited the
mine, that there existed, long previously to the discovery of the mineral treasures found in this hill, a
traditionary feeling that it was a marked spot, upon which sooner or later a great mine was to exist.
Whether this had its origin in some very early explorations or not could not be ascertained.
488
[BOOK II.
THE FORMATION OF DEPOSITS.
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Foster that in the deeper parts of the mine the flucan diminishes in width,
and at the bottom level is only a few inches thick. Or it may have been, that
two parallel fissures were formed by the same mechanical disturbance, for
one division—now called the Bastard lode—is a mass of Slate rock generally
4 or 5 fathoms wide between the flucan and the true lode. In the annexed
woodcut (Fig. 96) A A represent the country, which is composed of Lower
Silurian Slates, C is the clay or flucan lode, and D the Bastard lode, E being
the true metalliferous lode. The Bastard lode is a mass of Slate rock, having
on its south side the softened clay mass, probably Slate decomposed, and on
the north the true fissure lode. This lode (?) is softer than the country, and
is traversed by numerous strings of the sulphide of lead. Occasionally it
is rich enough to pay for
working, and in some stopes
above the 90-fathom level
the most productive part of
this lode was found. The
galena in the Bastard lode
was foliated in its character,
partaking much of the cha-
racter of the potter's ore of
Shropshire. Between this
and the true lode a wall or
division is generally found,
frequently consisting of a
yellow hornstone in which
a little blende is found. The
regular lode consists of
masses of Slate traversed by veins of galena. These veins are sometimes
mere strings, in other cases they become branches from 1 foot to 2 feet wide.
With the galena there are considerable quantities of blende, with quartz,
and some iron pyrites, marcasite and copper pyrites. Dr. Foster says: "In
several specimens I noticed the succession, I quartz, 2 galena, 3 blende,
4 quartz; but I am not sure that this order always holds good." It appears
upon a careful examination to vary considerably. This lode is a good example
of a brecciated lode. It is made up of fragments of slate cemented by quartz,
galena, and blende. The footwall of the regular lode is generally well
marked, and slickensides are frequently met with, and these striated surfaces
are often found in the joints of the lode itself. The fissure in which the lead
lode of the Van mine is found is said to be very extensive, but the length of
the ore ground varies with the depth, from 60 fathoms at the adit to more
than 200 fathoms at the 90-fathom level, 150 fathoms being reckoned as the
length of the very productive part of the shoot. A gas, said to be light
carburetted hydrogen, is found, as Captain Williams informed us, at the adit
level and in level below it when first the lode is tapped. The gas rushes out
with the water with much noise, and appears to come from a greater depth.
Occasionally this gas, mixing with the air, forms an explosive mixture (fire
damp), and, although no serious accident has happened, the miners have
been scorched by the flame and their hair singed. It is not easy to
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Fig. 96.-The Lode in the Van Mine.
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CHAP. IV.]
THE GOSSAN OF COPPER LODES.
489
account for the presence of carburetted hydrogen gas in such a lode as that
found at the Van. Sulphuretted hydrogen might readily arise from the
decomposition of the ores, combined with sulphur, and Dr. Foster says: "It
is not improbable also that sulphuretted hydrogen is emitted. I smelt this
gas very perceptibly in one part of the mine, and more strongly, I fancy, than
would have been the case if there had been sulphuretted hydrogen formed
by the decomposition of the potassic sulphide in the gunpowder smoke on
meeting with water." Captain Williams gave many reasons in proof of the
gas being light carburetted hydrogen, and he believed that it came, when
relieved from pressure, from a considerable depth. It is possible that the
lead lode, at some point not yet reached, passes through a bed of car-
boniferous shale, from which the gas may have been evolved. Occasionally
small quantities of an explosive mixture have been found in the deep mines
of Cornwall, but, in all cases, it has been traced to the decomposition of
wood-work in damp parts of the mine.
Gossan-Earthy Brown Iron Ore.—This is found so frequently near the
surface, especially, of copper lodes, and it is considered of so much import-
ance by the miner, that a brief space must be devoted to its consideration.
The largest proportion in the composition of mineral lodes is quartz, and
generally near the surface this is full of hollows and drusey cavities, which
are almost always filled in with this ochrey mass, termed by the miners
Gossan.
Gossan almost invariably accompanies copper ore in the upper part of
the vein. It is often found also in veins containing silver, and the mineral
substances, called in Cornwall scovan and capel-which may generally be
regarded as intimate admixtures of quartz and chloride (Burr).
When gossans contain metallic substances, they are tolerably hard, and
their ferruginous matter is in colour almost a chocolate brown, but they
often contain softer portions: for example, a friable quartz, locally termed
sugary spar, and also felspar-clay, often called prian (Henwood).
For this substance there is no precise mineralogical name. It varies much
in composition, and, as may be supposed,-since it is evidently the result of
decomposition of the lode above which it rests,-partakes to a certain extent
of the nature of the mineral veins. The miners in this country are guided
in their opinions as to the probability of a lode proving rich, by the appear-
ance of this ferruginous mass. "Keenly gossan," meaning kindly (promising),
is referred to by them with much show of knowledge. In the German mines
a similar deposit is noticed and termed by the miner eisenhath, or the iron hat
of the vein. They have a proverb, "There is no lode so good as that which
wears an iron hat.”
De la Beche says: "It has been found that the percentage of cases is
considerable where an iron-ochreous substance named 'gossan' prevails, and
copper ore is connected with it, and it may be said that the instances are very
rare where copper is found in fair quantity in a lode without gossan having
been discovered on the 'back' or upper part of the lode. This gossan, which
is generally mixed with quartz and other mineral substances, among which
oxide of tin frequently occurs, differs much in general aspect, and the
experienced eye of the miner readily detects that character which is most
490
[BOOK II.
THE FORMATION OF DEPOSITS.
indicative of a good copper lode, though it is one that can scarcely be
expressed in writing.'
"'*
Gossan appears to be the result of the decomposition of the upper portion
of a lode, exposed, as it will be, naturally, to the influences of atmospheric air
and of water. If we consider that a copper lode consists, usually, of copper
pyrites (a double sulphide of copper and iron), of iron pyrites (sulphide
of iron), and other similar constituents, the first being especially liable to
decomposition, we can readily account for the accumulation of masses
of oxide of iron, containing, as well, the other minor constituents of the
mineral lode in the exposed portions of the vein. "Veins commonly possess
the same general appearance in valleys, as in the contiguous hills . . . in
both situations the metalliferous veins are, usually, equally furnished with
'gossan' or other foreign matter overlying the ore." †
In lodes which contain gossan near the surface, there is generally a dimi-
nution of its ferruginous ingredients at greater depths. Where copper ores
abound, the earthy black copper, at first, is mixed with the gossan, the
proportion of the iron ore decreases, and that of the copper increases; whilst
in those portions of the lodes which are unproductive, immediately beneath
the gossan, the ferruginous particles are replaced by hard milk-white quartz
(Henwood). These facts are confirmatory of the view expressed, that the
gossans are entirely due to the decomposition of the yellow ore.
Nearly all the gossans contain silver. In the mineral district of the
Tamar a considerable quantity of silver has been produced by veins of a
gossany nature, chiefly in a finely disseminated state, and at no great depth
from the surface. The first discovery of silver in Cornwall is reported to
have been made at Wheal Mexico, in the Perran district. Dr. Berger says‡ :
"The vein which was formerly worked at Wheal Mexico in Cornwall, was in
grauwacke Slate. The ore appeared to be mixed in a gossan in the form of
insulated masses or nests; besides the native silver-muriate of silver or
horn silver-corneous ore was also met with.”
At Herland one of the cross veins yielded an abundance of silver, some-
times in the native state. In the shallower parts gossan accompanied it, the
whole being distributed through a white crystalline quartz, with numerous
vughs (cavities) which were often lined with capillary silver. A well-known
metallurgical chemist, a few years since, obtained some twenty specimens of
gossans, from the backs of some of the lodes in the mining districts of St.
Agnes and of Perranzabula. These were assayed with much care, and from
more than two-thirds of the samples weighable quantities of silver were
obtained, and from two of the specimens traces of gold.
Many years since a silver refiner from Sheffield visited Cornwall, and his
attention was directed to the gossans. He made some very careful examina-
tions, and purchased a sufficient quantity to freight a ship to Liverpool, from
which port it was conveyed to Sheffield by land. Notwithstanding the heavy
cost for carriage, he realised several hundred pounds by the silver which he
obtained.
*
Report of the Geology of Cornwall, Devon, and West Somerset." By Henry T. de la Beche,
F.R.S. 1839.
↑ Robert Were Fox, "London and Edinburgh Philosophical Magazine," vol. i. p. 239. 1832.
"Geological Transactions," vol. i. p. 171.
CHAP. IV.]
PSEUDOMORPHISM AND METAMORPHISM.
491
Mr. J. Carne informs us that many of the gossans are valuable for
the tin which they contain. He says: "An instance of the top of a
copper lode having been taken away for the sake of the tin which it con-
tained, occurs at Wheal Damsel and Wheal Spinster copper mines. The
Granite walls of the lode are still visible at the surface and to the depth
of three or four fathoms, having a space of about 4 feet between them. It is
probable that, if the rubbish were taken away, the space would be found to
extend to the depth of perhaps 10 fathoms, or as deep as the ancient miners
could go without being obstructed by water. From this space the fine gossan
of the copper lode was wholly taken away, and the tin ore extracted from it.
•
"Gossan has been returned for the sake of its tin, within the recollection
of some of the oldest miners living, but at present the expense of extracting
the small quantity of tin contained in gossan is so great in comparison
of what it costs to obtain it from other sources, that I believe nothing is
now done in that way."
It must be noticed that many rare and curious crystalline minerals occur
where gossan is plentiful. Mr. W. J. Henwood gives a list of some 16 mines
in which rare minerals have been found in the gossans. Lodes which afford
no gossan were, he says, formerly called scovan-lodes,† and he adds, "I have
often seen fine specimens of copper pyrites in gossan at Cœ-Mawr, near
Dolgelly, in North Wales," proving that the formation is not confined to
Cornwall.
+
+
Pseudomorphism—yevdńs, false; μoppń, form.—Without a short statement of
the phenomena included under this term our subject would be incomplete.
We have been discussing the question of the formation of gossan. This may
be regarded as an example of the changes which occur in minerals to
which this name has been given. The term is strictly applied to alterations
in the forms of crystals, but some authorities apply it to changes in the
beds of rocks, to which the term metamorphism is more correctly applied.
Dana, for example, says: "Thus all Serpentine, whether in mountain masses
or the simple crystal, has been formed through a process of pseudomorphism,
or, in more general language, of metamorphism. The same is true of other
magnesian rocks, as steatite, talcose, and chloritic Slates. The crystalline
rocks often offer examples of a similar change. The graphite of these
rocks may be but a pseudomorph-or metamorph-after some vegetable
product, and, as truly so, as the petrified wood of more recent times. Thus
the subject of metamorphism, as it bears on all crystalline rocks, and that
of pseudomorphism, are but branches of one system of phenomena; the
chemistry is the same in both."
This definition of the term does not appear to be strictly correct. The
change of pyrites, either of iron or of copper, into earthy red or brown iron
ore, can scarcely be regarded as a false form. It is a case of chemical
change. By the action of the atmosphere, the bisulphide of iron has parted
with its sulphur, and the iron has become an oxide-the gossan of the miner.
The change of felspar crystals into oxide of tin is a true case of pseudo-
*“Transactions of the Royal Geological Society of Cornwall," vol. iii. p. 41.
† Jars's "Voyages Métallurgiques," iii. p. 193; Pryce, "Mineral Cornubion," p. 90; Mr. Phillips,
"Geological Transactions" (Old Series), vol. ii. p. 118.
キ ​"System of Mineralogy," vol. i. By James D. Dana, A.M.
492
[BOOK II.
THE FORMATION OF DEPOSITS.
morphism. The felspar, by a natural process not quite understood, under-
goes a process of disintegration, and for every particle of the felspar
converted into kaolin (china-clay) and removed, a particle of oxide of tin
is deposited. Thus eventually the mould left in the Granite-of the felspar
crystal-is filled with the oxide of tin, which retains the true form of the
felspar mould. As stated, the grains of tin-each one of which may be
regarded as a crystal, more or less perfect-retain their form; but as each
addition is made, crystal unites (agglutinates) to crystal, and the final result
is a cast in oxide of tin of the original felspar crystal, made in a felspar
mould. Crystals are obtainable from the Granite of Wheal Coates in St.
Agnes, and also from one or two mines in St. Just, in every stage of change.
Professor Bischof has the following misleading note*: "Some geologists
hold that there is a third class of pseudomorphs, produced, by a deposition
of substances in cavities left in rocks by the solution of imbedded crystals.
This process would be analogous to casting in a mould. There does not,
however, appear to be any evidence in favour of this view, or any proba-
bility that a crystalline mineral introduced into such a cavity would assume
the form of the cavity and not proper to itself."
Dana mentions petrified wood as an example of pseudomorphism. It is
so; for every particle of wood removed from the tree, a particle of silica
has taken its place, until the woody substance has entirely disappeared, and
silica alone remains; the flinty mass retaining with great delicacy the true
woody structure. Dana thinks that pseudomorphs should be classed under
four grand heads-
1. Pseudomorphs by alteration.—Those formed by a gradual change of com-
position in a species; e.g. change of augite to steatite, or soapstone.
2. Pseudomorphs by substitution.-Those formed by the replacement of a
mineral which has been removed, or is gradually undergoing removal; e.g.
change of Felspar to oxide of tin-the petrifaction of wood.
3. Pseudomorphs by incrustation.-Those formed through the incrustation
of a crystal, which may be subsequently dissolved away; often the cavity is
afterwards filled by infiltration; c.g. change of fluor-spar to quartz.
Some interesting specimens of this order have been obtained, in con-
siderable quantities, from the Virtuous Lady copper mine near Tavistock.
Carbonate of iron had covered cubical crystals, probably of fluor-spar, which
had been formed on bisulphide of copper, and had entirely disappeared,
leaving cubical cavities, produced by the crust of the carbonate of iron. In
these cavities, some of which were large, quartz and bisulphide of copper
had crystallised, filling them up only in part. In this mine some remarkable
pseudomorphs called “Ladies' Slippers" were also found.
Haidinger has described † many alterations depending upon gradual
changes which take place in the interior of minerals while their external
forms remain the same. Under the head of "parasitic formation of mineral
species," he has noticed changes which have been produced on substances
having the same composition, and on others which contain copper, iron, lead,
* "Elements of Chemical and Physical Geology," vol. i. p. 19. By Gustav Bischof, Ph.D. (Cavendish
Society's Transactions.)
+Transactions Royal Society of Edinburgh," vol. ix. p. 73.
CHAP. IV.]
PSEUDOMORPHS BY PARAMORPHISM.
493
He adduces many
manganese, barytes, antimony, and earthy minerals.
new compounds which have taken the form of the original crystals, appa-
rently by gradually displacing their constituent parts. Haidinger states
that "Professor Mitscherlich exposed crystals of hydrous protosulphate of
iron, immersed in alcohol, to a degree of temperature equal to the boiling-
point of that liquid. Decomposition ensued, though the external shape of
the crystal remained unchanged. On being taken out of the liquid and
broken, each of them was found hollow, and presented a geode of bright
crystals deposited in the planes of the original ones. The crystals had the
form of low eight-sided prisms, belonging to the prismatic system, and were
proved by analysis to contain exactly half the quantity of water which is
required in the mixture of the original species."* These may be included in—
4. Pseudomorphs by paramorphism.-Such as are formed when a mineral
passes from one dimorphous state to another; e.g. change of aragonite to
calcite.
These changes are not always distinguishable. In some cases a change
may take place through alteration of the surface; and then, this process
ceasing, the interior may be dissolved out, leaving a pseudomorph like one
of incrustation, or a pseudomorph which appears to be the result of alteration
explicable on chemical grounds, may be wholly due to substitution simply.
The term paramorphous crystals was first used by W. Stein, and adopted
by Scheerer,† to designate certain pseudomorphs in which a change of mole-
cular structure has taken place without alteration of external form or
chemical constitution. As, the monoclinic crystals of fused sulphur, which
gradually become opaque, and are then found to be made up of crystalline
particles having the trimetric form of sulphur crystallised from fusion at low
temperatures or of aragonite altered internally to calc-spar and of iron
pyrites altered internally to marcasite.‡
Dana gives a very long list of substances, including the elementary
bodies in which these phenomena occur. Native copper, which imitates red
copper and aragonite. Native antimony, which imitates Valentinite; and
of Graphite, which imitates pyrites.
"These examples of pseudomorphism," Dana says, "should be under-
stood as cases not simply of alteration of crystals; but, in many instances,
of changes in beds of rocks. Thus all Serpentine-as already stated—
whether in mountain masses or in simple crystals, has been formed through
a process of pseudomorphism.” Metamorphism, as it bears on crystal-
line rocks, appears to be the result of decomposition, usually produced by
heat, as by the intrusion of masses of igneous rock; and is, certainly, not-
withstanding the dictum of Dana, in several respects different from pseudo-
morphism.
We have already stated that lodes containing copper pyrites are often
changed above to red or black copper ore: a change which is, as we have
shown, produced by the slightest alteration in the electrical condition.
Impure chrysocolla (silicate of the oxide of copper), or malachite. The former
* "Transactions Royal Society of Edinburgh," vol. xi. p. 79.
+"Journal Pract. Chemie," lvii. p. 60.
See Scheerer, article Paramorphose, in the "Handwörterbach der Chemie," vol. vi. p. 53.
494
[BOOK II.
THE FORMATION OF DEPOSITS.
is frequently found investing the latter. Mixed with the gossan we find
disseminated all the sulphides, arseniates, &c., that are associated with the
copper ores of the lodes. The erubescite (purple copper ore) of the upper part
of a copper lode is supposed to be a comparatively modern product, arising
from the alteration of vitreous copper. Phosphates, and arseniates of copper,
lead, &c., carbonates and sulphates, are among the surface species, or those
that occupy the upper part of metallic lodes. They are the result of altera-
tions within the depths to which atmospheric agencies penetrate.
We have already noticed the experiments of the elder Becquerel, which
established conclusively the influence of weak electrical current in producing
chemical change. Without doubt the changes we have been describing are
due to the electro-chemical power which is produced whenever a compound
body, such as a mineral ore, undergoes decomposition. A simple experi-
ment will prove this most satisfactorily. Into a glass jar we place a solution
of muriate of barytes, B, and pour carefully down the
sides of the vessel some pure water, so that it float on
the barytic solution as shown at A. A piece of yellow
copper ore, which is a compound of sulphide of iron
and sulphide of copper, is suspended by a string, and
hung from a bar placed across the jar, so that one half
of the ore is in the solution of muriate of barytes, and
the other half in the water. If this is allowed to stand,
it will, after a short time, be seen that the half of the
yellow copper ore which is in the barytes solution will
Fig. 97.
begin to change colour, and gradually a fine white cloud
will form around it, and a fine powder fall through the fluid to the bottom of
the vessel. This will be sulphate of barytes. The sulphur of the ore will be
converted into sulphuric acid, and this will combine with the barytes form-
ing the insoluble sulphate. As this process goes on, the copper ore will
become iridescent, and eventually be changed into grey copper ore, sulphide
of copper, and a film of oxide of iron will gather on the sides of the glass at
the line of junction between the two fluids, thus representing precisely the
conditions under which gossans are formed on the backs of copper lodes.
If the experiment is carried out with proper precautions, and, after a time,
when the changes have gone on for a few weeks, if the ore be weighed, it
will be found to have lost weight, and loss will be found to be the sulphur
of the sulphuric acid combined with the barytes, and the iron in the oxide of
iron film formed upon the glass.
"The causes of change," says Bischof,* "are the simplest and most
universal operations about us. (1.) The solvent power of ordinary waters,
cold or hot, or of steam. (2.) The reaction, according to chemical principles,
of the ingredient dissolved in those waters, or in mineral or sea waters,
heated or at the ordinary temperature. (3.) The progress of gradual oxy-
dation to which some substances are liable, and the reaction of substances
thus formed on the ingredients at hand, aided or promoted by electrical
currents or heat. (4.) The action of exhaling gases from the earth, with or
without volcanic action." The Professors Rogers subjected a large number
*Gustav Bischof, "Chemical and Physical Geology."
CHAP. IV.]
ASSOCIATION OF MINERALS AND ROCKS.
495
of minerals in powder to the action of water containing carbonic acid by
filtration. Some gave evidence, at once, of the solution of the substance
experimented on. Pure water gave with many of them a like result, but
more slowly. The result obtained, according to Bischof, illustrates two
important facts:-
1. That ordinary waters upon and through the Earth's surface are con-
stantly active in dissolving and decomposing minerals and rocks, and even
the species reputed indestructible are thus acted on.
2. That the waters are thus furnishing themselves with chemical agents
for effecting other changes.
A few more facts connected with the changes in the minerals, which we
have been considering, will be of interest.
Mr. R. W. Fox observed the yellow sulphide of copper in the form
of crystals of carbonate of iron, which it must have gradually displaced,
sulphide of lead—in six-sided prisms-termed blue lead, having superseded
the phosphate of that metal, pseudo-hornstone projecting through the centre
of a crystal of octohedral fluor.*
M. Becquerel states that M. Darect left a plate of steel during eight years
in a case, at the Mint of Paris, in contact at one of its ends with a solution of
nitrate of silver, which reached it very slowly from a fissure in the vessels
containing it. One half of this steel plate was entirely changed into very
pure silver, offering a resisting mass without the least trace of iron. The
volume of the plate of silver was visibly the same as that of the plate of
steel. Becquerel thinks this singular effect must have been produced by
actions analogous to those which have converted antique bronze coins into
the protoxide of copper. This is not pseudomorphism.
The production of pseudomorphs appears to depend upon an incrustation
of the original crystal, or some other accidental circumstance. The number
of instances in which the form of the original mineral is destroyed, and the
product of the change appears in its own crystalline form, is by no means
unimportant, and it would be still more important if, after the completion of
the change, those characteristics were not wanting which might enable us to
decide whether this or that mineral had furnished the material.
The association of minerals in rocks has an intimate bearing on the question
of their origin. Associated minerals may obviously have been either con-
temporaneously or successively formed. If the former, the species were alike
in this general phenomena attending their origin; if the latter, there may
still be many circumstances in common arising from their condition in the
same rocks, or their dependence on the same system of causes, or from the
earlier contributing more or less to the material of the latter; or, again, they
may have no relation except that of relative position (Dana). Breithaupt,†
Bischof, Delesse, and others have paid great attention to this subject, and
have given groups of associated species, from which the following few
examples are quoted:-
Serpentine.-Diallage, hornblende, pyroxine, pyroselerite, chromic iron,
brucite, hydromagnesite, aragonite, dolomite, emerald nickel, pyrope.
* "Reports of the Royal Cornwall Polytechnic Society," 1836.
+ "Paragenesis of Minerals."
496
[BOOK II.
THE FORMATION OF DEPOSITS.
Tin Ore.-Wolfram and scheelite, molybdenite, magnetic pyrites, tour-
maline, fluor-spar, beryl, topaz, apatite, pyrrchlore, native bismuth.
Galena.-Blende, copper pyrites, calcite, heavy spar, spathic iron, quartz,
fluor-spar, pyrites, tetrahedrite.
Copper glance.-Grubuscite, native copper, malachite, red copper, pyrites,
copper, galena, blende, iron pyrites.
Cobaltine.—Cobalt and nickel ores, mispickel, magnetic pyrites, axinite,
copper pyrites, limonite, &c. &c.
As this bears directly on the appearance of metallic minerals in certain
rocks-as tin and copper in Clay-Slate, and lead in Limestone-the reader
should consult again the pages devoted to what has been termed "the rock
conditions" in relation to mineral veins.
"I consider," says Bischof, "that the entire removal of fluor and calc spar
from a whole series of veins, and the introduction of an equal quantity of
quartz in their place, is a matter of vast importance. And how do we know
that this has actually taken place? Because we find quartz in the form of
fluor and calc spar. Is it not to be inferred from this fact that far more
stupendous displacements have taken place where the processes have con-
tinued longer? To what enormous spaces of time we come when we reflect
upon the periods during which the fluor and calc spar were introduced into
those fissures, and then the periods during which these minerals were again
removed by water, and quartz substituted in its place."
The following passage, abstracted from Professor Bunsen, forms a pecu-
liarly appropriate conclusion to this chapter. "Pseudomorphs furnish us with
a kind of knowledge which we have no opportunity of deriving from any other
source. It will scarcely ever be possible to convert augite, olivine, or horn-
blende, &c., into Serpentine in our laboratories. But when we find Serpentine
in the form of those minerals, this fact is sufficient evidence that such con-
version can take place; and if in any given instance there are geognostic
reasons for the opinion that one or other of these minerals, or even several
together, have furnished the materials for the formation of Serpentine, there
is a high degree of probability that such a change has actually taken place."
In considering the operations of Nature, we should never forget that
TIME is an all-important element in her works, and that subtile forces are
ever slowly and silently producing the grand phenomena of creation.
BRITISH MINING.
BOOK III.
PRACTICAL MINING.
K K
CONTENTS OF BOOK III.
CHAP. I. DISCOVERY OF MINERAL LODES, AND THE OPENING OF MINES.
II. PRACTICAL OPERATIONS FOR THE EXTRACTION OF METALLIFEROUS ORES.
III. VENTILATION of Mines, Drainage of MINES, ETC.
99
IV. DRESSING OF METALLIFEROUS ORES; PREPARATION FOR THE SMELTER.
""
V. DISCOVERY AND EXTRACTION OF IRON ORES FROM VEINS AND OTHER DEPOSITS.
BRITISH MINING.
BOOK III.
PRACTICAL MINING.
CHAPTER I.
DISCOVERY OF MINERAL LODES, AND THE OPENING OF MINES.
IN the preceding pages the historical sketch of mining will have made careful
readers acquainted with the steps by which the discovery of mines has been
made. The methods adopted, to render our subterranean explorations of
value, by disclosing the hidden treasures of the Earth's crust, will form the
subject of the present chapter.
Experience has instructed us,-often at very considerable cost,-in the
peculiarities which mark a mineral district. We know now that there are
certain localities, within the area of which we may reasonably hope to find
mineral wealth, and that there are other well-defined regions which we know
to be absolutely sterile. These facts have been already explained, therefore it is
not necessary to repeat the explanations here. If we examine Cornwall or
Cumberland, Devonshire or Derbyshire, or Durham, Wales, or Westmore-
land, we shall find that over every square mile, within which there was the
remotest probability that mineral ores might exist, the ancient miners have
left traces of their unwearying industry. We are, therefore, instructed,
by the labours of our forefathers, where to search for treasure, and they have
indicated to us the spots where, in all probability, any exploration would end
in disappointment. The successes of our ancestors, and the failures of the
"old men "-as the ancient miners were called-should be guides and guards
to all modern explorers.
It has been shown that tin is to be found, as a rule, only in the Clay-Slate
rocks, which exhibit a peculiar colour and character, or in a coarse Granite
which is broadly distinguished from such as would be selected for a
building stone. We know that Elvans, the Toadstone, and other rocks,
which are evidently of igneous origin, have a very marked influence on the
occurrence of metallic ores. Copper ores certainly show a tendency to
accumulate in fissures, which have been prepared to receive them, in the older
rocks and near the junction of dissimilar formations. Lead ore is found in
geological formations of widely different ages, but it more especially appears
to show an affinity for Limestone.
K K*
PRACTICAL MINING.
[BOOK III.
500
Again, we know that the direction of fissures indicates that some influence
is exerted on the deposits, as they take a bearing which has some relation
to the lines of magnetic force. This is a point on which we have numerous
indications, but the question requires an examination which has not yet been
given to it. For one or two varieties of ore, an easterly and westerly strike
appears to be the most favourable; but we have examples, which are
especially instructive, showing that very wide deviations must be accepted,
as being within the limits of the production of profitable mineral veins.
Notwithstanding the attention which has been directed to the laws
regulating the deposits of metallic ores, it must be confessed that we are still
without any certain guide to the presence of lodes beneath the surface of
the Earth.
"By cutting the ground
The metal is found,"
continues to be almost as true now as it was two centuries since, and the
miners' phrase—
"Where it is-there it is,"
remains a truism, notwithstanding our boasted applications of science. This
is a very humiliating confession to make in these days, when every inducement
is given, by instruction in mining schools and science classes; but as even
the discovery of mines remains a mere matter of guessing, it is not possible
to give any rules which can be regarded as reliable. Dr. Borlase,* generally
a very clear observer, after he has described the occurrence of tin in streams,
writes: "Tin ore is also found dispersed in the body of the stone, dispersed
in spots and bunches, where there appears no fissure, lode, floor, or rectan-
gular intersection, as in other strata. These spots are sometimes so large and
numerous when in Granite (as in Trevegean, in St. Just) that they will
require the labour of the miner, though he is generally obliged to blast the
rock, and afterwards break it with sledges, in order to get at the tin. If
these spots be in the blue Elvan stones (as we find them near the Land's End),
no iron will pierce the stone, neither can it be blasted with gunpowder." This is
quoted as an illustration of the imperfect knowledge which prevailed at
the time this was written. After giving several accounts of the modes of
occurrence of tin, Dr. Borlase continues :—
Having now considered the several states and situations in which tin is
found, it must be observed that tin does not appear so frequently in either,
or all of them together; but that people are perpetually searching after
more, and endeavouring to make fresh discoveries. To say nothing of
dreams and fires by night, motives equally illusive, though prevalent still
among the vulgar, few of the Cornish have ever heard of the virgula
divinatoria and its virtue in discovering lodes. Having already given
a full description of the divining-rod and its uses, it is only necessary in
this place to direct attention to the very recent period at which the use
of it was but little known. Neither are they often (perhaps not so often
as they should be) directed by the taste and colour of waters. The run of
a lode is sometimes discovered by the barrenness of the surface and want
or weakness of grass in a particular furrow; thus in the tenement of Treve-
thick, in St. Agnes parish, though the field is cultivated equally in every
* "Natural History of Cornwall," 1758.
•
CHAP. I.]
THE DISCOVERY OF MINERAL LODES.
501
part, you can distinguish the course of the lode by the unequal growth of the
grass. This must be owing to one of two causes: either there is so much
mineral salt below the soil, that the roots of the plants are parched, or the
earth and substance of the lode is so porous that all the nourishment of the
manure is dissipated and sinks below, instead of being raised into the
plants. Much surer indications of treasure are often found in cliffs and
caverns, where the lodes, laid bare for some fathoms in depth, may easily be
examined at several stages. Some of the curious will think, that discoveries
may be made by observing the position and alteration of the several strata as
we descend into our mines; but there is no uniformity to be assumed in
the strata of one hill and those of another half a mile off . . and therefore
no judgment can be formed from the situation of the strata in one place,
where, how, or in what condition lodes are to be found in another place."
After mentioning the driving of adits, Dr. Borlase proceeds :-
"It is much easier and less expensive, and therefore most common, to
trace lodes by the scattered fragments of them called shodes, and as this is a
kind of science which few tinners understand, but those who have chiefly
applied themselves to these researches, it will require more particular notice."
Before continuing this quotation it will be more satisfactory to give
Borlase's own definition of a shode stone. Referring to the broil, or bryle of a
lode, that is, the disintegrated portions of a mineral vein, found at, or near, the
surface. From this, Dr. Borlase supposes loose stones have been removed.
He was not sufficiently acquainted with geology to be aware of the vast
quantity of matter which has been removed from the surface of the Earth,
and the consequent destruction of the lodes themselves. However, supposing
lode-stones to have been derived from the broil, he continues :-
"The smaller stones are carried farthest; on the contrary, the largest
stones are nearest the lode. The smaller are also nearer to the surface of
the ground; but the larger ones deeper and still deeper as you approach
the lode till the last are found contiguous to the Iode itself. The farther
distant these stones are from the lode the fewer they are in number; but
they multiply as you come nearer, and are always in greatest plenty next
the lode. These stones are known from all others by their being of a
different colour and structure from the shelf-rubble and other common stones
of the ground where they lie; but more particularly their angles being worn
off, and the farther distant they are from the lode the smoother they are, and
the nearer, the less are their angles blunted. In Cornwall we call these dis-
persed parts of the broil shodes, perhaps from the Teutonic word shutten, to
pour forth." The searching for these stones is called shodeing.
"If the
shode is found in the vegetable soil it gives no evidence of any lodes being
nigh; but if in the fast (that is, the rubble or clay never moved since the
flood) it is taken as a never failing proof that it came from a lode farther up
the hill. As soon as the shode is found impregnated with tin, to find the
lode it came from is the next care. The process consists in digging pits at a
proper distance, depth, and in proper direction, and judiciously regulating
their advances to the lodes according as the properties of the shodes direct.
First, the run of the lodes being known to be in the hill above the shode, the
several declivities below the hill, and where water may be supposed to have
run with greatest force, must be considered, and there, at right angles to
K K 2
502
[BOOK III.
PRACTICAL MINING.
such force must the shafts be placed crossing such declivities." This pro-
cess is called in the Cornish tongue costeaning, from cothas-stean, i.e. fallen or
dropped tin, and the pits or shafts sunk are costeaning pits or shafts.
W. Pryce, who wrote in 1778,* devotes many pages to the consideration
of the divining-rod, of which he says: "The merit of the essay on the
virgula divinatoria is due to Mr. William Cookworthy of Plymouth,† and
though the virtues of the rod may not be easily allowed by the incredulous,
yet, for my own part, I want no further evidence of its properties than I have
already obtained to fix my opinion of its virtues." Although a conscientious
believer in the virtues of the divining-rod, Pryce was a remarkably clear-
headed man and a careful observer. He says, with much truth :
"The principal investigation and discovery of mines depend upon a
peculiar sagacity, or acquired habit, of judging from particular signs, that
metallic matters are contained in certain parts of the Earth not far
below the surface. But as ignorance and credulity are the portions of the
illiterate, we have people constantly in search for tin, where our dreaming
geniuses direct them to follow after the images of wild fancy; consequently,
we have a Huel Dream in every mining parish, which raises and disappoints
by turns the sanguine hopes of the credulous adventurers."
All this is as strictly true in 1883 as it was when Pryce wrote. He also
says: "Mines have often been discovered by accident, as in the sea cliffs,
among broken craggy rocks, or by the washing of the tides or floods; like-
wise by irruptions and torrents of water issuing out of hills and mountains,
and sometimes by the wearing of high roads. Another way of finding veins,
which we have heard of from those whose veracity we are unwilling to
question, is by igneous appearances, or fiery coruscations. The tinners
generally compare these effluvia to blazing stars, or other whimsical like-
nesses, as their fears or hopes suggest, and search with uncommon eagerness
the ground which these jack-o'-lanthorns have appeared over and pointed out."
Pryce evidently doubted the truth of these luminous appearances. These
forms of ignis-fatuus have been so often vouched for by reliable authorities
that there appears to be no reason why phosphuretted, or potassiuretted
hydrogen, should not be formed in marshy places, and both of these gases
are spontaneously inflammable. At Swanpool, near Falmouth, such meteors
are said to have been seen. The conditions at this place are, a small lake
separated from the sea by a bar of sand, and beneath the lake a large lode of
a curiously composite character which has been worked on. It has been
stated by authorities—who could scarcely be doubted—that, under peculiar
conditions of the atmosphere, the ordinary morass meteors have been seen
flitting over the lake. The same kind of phenomena have been reported
from other mines, but no evidence has been so precise as that relating to
the Swanpool mine.
Meteoric appearances of another kind were reported as not unusual at
the United mines when working. A large lode in one part of the sett is
crossed by a caunter lode, and both have produced ores, but different in
kind. One of the principal managers of this mine stated that he has often
seen, in the early morning, two banks of cloud, or vapour, floating along
* "Mineralogia Cornubiensis."
† The discoverer of China-Clay, and originator of the manufacture of Plymouth china.
CHAP. I.]
ON SHODES AND THE “BRYLE" OF LODES.
503
lines run in the same direction as these lodes. These banks of thin fog
observe most strictly the line of the lode, and of the caunter, and they
remained until the sun or the wind dispersed the vapour.
Pryce, after referring to the indications given by springs of the presence
of copper, which may be detected by a piece of bright iron, or by a piece of
tallow, says: "The iron in one case becomes coated with a copper film, and
the tallow in the other is tinged of a green colour." He then devotes some
pages to the virtues of the divining-rod, discoursing with much apparent
learning on the philosophy of "the moving corpuscles," and "the conditions
of the medium in which they move." Even in the present day many expe-
rienced miners,—and, in general, thoughtful men,—argue on the possibility of
the action of some electrical force, or of some occult power, in obedience to
which the rod bends to the Earth. The influence of the divining-rod is analogous
to that of a turning-table, or of a whirling hat. Without human aid neither
the one nor the other exhibits any power to move; therefore, the only safe
conclusion is to regard the operator as the instrument of motion, and the
movement as the result of what has well been called "a fixedness of idea,"
which, in its influence, may be regarded as one of the many psychological
phenomena which yet require elucidation.
We have quoted Borlase on the matter of shodeing; a few notes from Pryce
may with advantage be added. The following paragraphs are therefore
abstracted from Pryce's "Mineralogia": "Henckell and Rösler say, that
Mundick shode is very common, and that Wolfram, Granite and iron corns,
nay quicksilver, are found in shode and stream, all of which Henckell says,
were washed or torn away from their veins by the violence of the Noachian
Deluge." Copper and lead shodes are very seldom met with; their “bryles
being chiefly composed of 'tender unmetallic gossan,' which is not miner-
alised into copper ore at the bryle."
Obscured by the quaint language in which it is written, the following
statement by Pryce covers a considerable amount of truth: "Almost every
lode has a peculiar coloured earth or grewt (grit) about it; which is also
sometimes found with the shode, and that in greater quantity, the nearer the
shode lies to the lode; beyond which that peculiar grewt is seldom found
with the shode. A valley may happen to lie at the foot of three several hills,
and then they may find several deads grewt, or earth moved by the waters of
the deluge, but not contiguous to the lode, with as many different shodes in
the middle of each. This is also termed the run of the country; and here the
knowledge of the cast of the country, or each hill in respect of its grewt, will
be very necessary for the further tracing them, one after the other, as they lie
in order."
"When the miners find a good stone of ore or shode-stone in the side or bot-
tom of a hill, they first of all observe the situation of the neighbouring ground,
and consider whence the deluge could most probably roll that stone down
from the hill, and at the same time they form a supposition on which point.
of the compass the lode takes its course, for if the shode be tin or copper ore,
or promising for either, they conclude that the lode runs nearly east and west,
but if it is a shode of lead ore, they have equal reason to conclude that the
vein goes north and south."
The above refers especially to the mineral district of South-western
504
[BOOK III.
PRACTICAL MINING.
England; but, with very slight differences, it applies equally to the mines of
Mid-England and the Northern counties. As an example, Westgarth Forster,*
in his chapter "On the Discovery of Mines," writes:-
"The peculiar signs of a latent metallic vein seem deducible to general
heads, such as—
"1. The finding of pieces of ore on the surface of the ground-(Shode
stones).
"2. The discovery of certain mineral waters.
"3. The finding of veinstone or rider.
66
4. The finding of metallic sands.
5. The discolouration of the trees or grasses in particular situations.
"6. The ascension of warm exhalations and the like, all of which are so
many encouragements for making stricter search near the places where such
symptoms appear. But when no evident mark of a mine appears externally,
the skilful mineralist sinks or drives into the earth in such places as, from
some analogy of knowledge gained by experience, or by observing the situa-
tion, course, or nature of other mines, he judges may contain metallic ores.
When the mineralist has reason to suppose that certain veins bear towards
any particular spot, the most effectual way of proving their existence is by
driving an adit or level from the lowest ground across the bearing of the veins,
by which means there is a certainty of cutting all the veins within the limit
of his level."
Most lodes come to the surface of the rock in which they are enclosed;
but this surface may be covered to some depth with drift deposits, or buried
up beneath vegetable mould. This has of course to be removed or sunk
through, and the "shelf," or surface of the rock, is carefully cleared, and
broken into for the purpose of exposing the lode. It is important in all
cases in "prospecting" for lodes-as the process of searching is called-to
make ourselves well acquainted with the bearing of the mineral lodes in
the district. Although lodes may, and do, vary in their relations to the
magnetic meridian, they usually observe some relation to each other. Refer-
ence to the map, or to the plans, which have been given, will show this.
In all plans the bearing of the lodes becomes a point of considerable
importance. It is easy to determine true north, by observing the shadow
cast by a rod, fixed vertically in the earth, at noon; and by observing a
compass-needle, it will be found that the magnetic north and south will
deviate from the line of true north. On all plans the magnetic north should
be carefully expressed, and the amount of declination (variation of the
magnetic-needle) correctly noted at the date of the survey.
In England the bearing of lodes is referred to the points of the compass,
as being so many degrees from the true north. The magnetic north is
a variable point. At present (1883) time the variation of the compass at
Greenwich is 18° 15′ west. Therefore to find the true north, in or near
London, by means of a magnetic-needle, the compass must be so placed that
the north end of the needle points 18° 15' west; the north and south lines of
the dial then will be in the true meridian. The declination alters according
to the position of the place. In Dorsetshire and in Yorkshire it will be
19° 15'; in Devon and Cornwall and in Durham, 20° 15', and so on.
* "A Treatise of a Section of the Strata," &c. By Westgarth Forster.
CHAP. I.]
on.
SEARCH FOR LEAD VEINS BY HUSHING.
505
In Germany and some other countries the old system prevails of
referring the bearing to a circle divided into hours; thus, a lode will be
said to strike three, or to run from a certain point towards midnight, and so
In the hilly districts of Yorkshire, and the Northern counties gene-
rally, the miners talk of a vein dipping towards the two or three o'clock sun.
It has been noticed that most lodes appear at the surface.
The appear-
ance of a lode at the surface may give but a very slight indication, yet
it is rare indeed that some signs are not observable. Ore may not be found,
but the fissure, however slightly it may be, filled with clay or gossan, is
always discovered by a careful searcher.
In Cornwall no copper ore of any value has been raised till 30 or 40 fathoms
in depth has been reached. The great mine of Preibram in Saxony had
to be sunk 20 or 30 fathoms before it became productive; although the lode
was large at the surface, but filled only by soft brown iron ore (Smyth).
In searching for mineral veins we have to determine the course of outcrop
of some lode already known. It is necessary to take the average direction of
the lode for some hundreds of fathoms in order to avoid errors, which may
arise from the inequality of the ground. It will be evident that a lode, in
passing through a valley, will be carried down the valley in the direction of the
dip. Many miners believe that if a lode is heaved by a cross course, it is sure
to come back again into the original line; but this is exceedingly doubtful.
In many parts of the world the lodes stand above the ground as distinct
ridges. This is especially the case with the quartz reefs of gold-pro-
ducing districts. In this country this is very seldom seen; sometimes a
depression of the ground may reveal the position of the back of a lode.
On the Moors of Yorkshire, and in Flintshire and Cardiganshire and other
districts, such depressions often indicate the position of a mineral vein.
In the Moorland districts of the North of England, the miners have
a process, called by them hushing, which they frequently use in searching for
lodes. Their method is, first, to construct a pond and accumulate as large a
quantity of water as possible. When sufficient water is collected, the wall
of the pond is cut, and it is allowed to rush suddenly down towards a stream,
tearing up the soil as it goes. This process of washing serves the purpose
of cleaning the rock for examination; the indications of lead, if it exists, are
obtained, and occasionally large masses of lead ore have been discovered by
the process. The practice of hushing is wasteful, as a large quantity of
valuable soil is often carried away and entirely lost.
HAND BORING.-The next process to be described is that of boring holes in
the earth, which is carried out extensively in searching for minerals deposited
in beds, but in the search for unstratified deposits the process is not, in all
cases, of so much importance. Still, occasionally, conditions present them-
selves which render it convenient to use the most simple form of borers to
pierce the soil, or deposits of sand and gravel, and even to penetrate the upper
and always softer, parts of the rock, for the purpose of ascertaining if any ores
of value exist beneath. For this purpose a very simple kind of apparatus is
used. A.general form will be that of a cylinder with a cutting edge round the
bottom and a slit up one side, very much like a gimlet. These tools are
worked by a handle fixed to the tool, or by a bar of wood passed through
an eye in the handle of the tool. If the boring is required to go deeper than
506
[BOOK III.
PRACTICAL MINING.
can conveniently be carried out by the hands of one or two men, unaided by
mechanical appliances, it is usual to adopt the following method :—
The surface arrangements are shown by Fig. 98. In ordinary practice
a well is first sunk of such a depth that the boring apparatus can be fixed
in it; and thus, a stage raised from the surface of the ground is dispensed
with. A stout plank floor, well braced together with boards nailed trans-
versely, and resting on putlocks, forms the stage. In the centre of the floor
is a square hole, through which the boring-rods pass. The plant required
consists of a spring-pole A, to assist in giving the necessary motion to the
rods when at work, the three legs with pulley blocks, chain, and roller or
windlass for drawing or lowering the rods, and the several lengths of rods
required, with various chisels, pumps, &c.
Boring is commenced by digging a small pit about 6 feet deep; over this
is erected three legs, pulley, &c. Sometimes a few feet of iron tubing is
B
A
D
Fig. 98.
C
E
inserted for
the purpose
of protecting
the sides of
the borehole.
The bor-
ing-rods are
from 10 to 20
feet long.
First the
chisel is in-
serted, then,
as the work
progresses,
the rods are
added. At
the top of
the rods are
two handles
placed at
right angles to each other, by means of which the rods are worked up and
down, at the same time altering the position of the chisel by a circular
motion. As the depth increases, the men at the cross-bar or handles are
assisted by means of a lever, A, at the surface, one end being firmly fixed in the
ground between two posts, B, the other being allowed to pass over the hole.
From the end of this pole the bore-rods are attached by means of chains, C,
thus every time the borer strikes the chisel, the lever enables them to lift the
rods high enough to give the necessary impetus to them for the next blow.
The chisel is occasionally withdrawn, and a long bucket, with a hinged valve
at the bottom opening upwards, is attached to the rods and lowered into the
hole. The borer presses this down upon the material, broken up by the chisel,
the débris becomes enclosed in the bucket, and it is drawn to the surface.
CHAPTER II.
PRACTICAL OPERATIONS FOR THE EXTRACTION OF METALLIFEROUS ORES.
THE use of the borer for the discovery of mineral deposits has been noticed
in the previous chapter. It is, however, frequently desirable to employ the
hand-boring machine in subterranean operations, and for this purpose the
machine illustrated-Fig. 98—may be used. The various parts of the borer
for underground work are of the same description as those used in the
vertical machine, only they may be more lightly made. The rods are
drawn out of the hole by the rope, the weight, which hangs in a small pit
suspended by the rope, being raised at the same time. The rope is then
slipped, and the falling weight drives the rods in the hole again. The rods
are kept steady and horizontal by being caused to run over a small roller
fixed on the frame, and also by moving a slide block adjusted by a screw
and nut. After using the chisel for some time, the rods are withdrawn, and
the pump, or scourer, introduced to clear away the débris, the other work
being carried on as with ordinary vertical hand-boring.
It proves convenient in this place to consider the application of boring
machinery in mining operations in its more advanced form. The simple
arrangements already described may prove exceedingly useful in many
places and under very varied circumstances. For example, it is often
necessary, when advancing towards old workings, or the supposed position
of old workings, known to be filled by water, to penetrate the rock in advance
of the workings by bore-holes, and thus tap the source of danger. The same
advantage is to be made available when large accumulations of carbonic acid
or other gases are suspected. We have now, however, to enter on the
consideration of rock-boring machinery in all its more important bearing on
mining.
ROCK-BORING MACHINERY.—A few years only have elapsed since rock-
boring machines were rendered successful in subterranean operations. At
this time their application extends to most of the mining centres throughout
the globe. In years to come this class of machinery, mitigating the miner's
toil and aiding the object of his research, will occupy yet a more distinctive
and important position. There is now no difficulty in applying ordinary boring-
machines to wide stopes, for the purpose of extracting the ore, to rising and
sinking on the lode, to sinking shafts in the country rock, and to all the
varied purposes of mining.
In connection with the mechanical boring of shot-holes and removal of
the ground, the miner has fortunately been aided by new explosives of unsur-
passed strength. The result has been that, under the observance of a skilful
and judicious system of working, a rate of progress in sinking shafts and
508
[BOOK III.
PRACTICAL MINING.
driving levels has been obtained, which is of the most beneficial character.
To attain a quick rate of speed it is indispensably necessary to have recourse
to good boring machinery, strong explosives, quick charging and blasting
the shot-holes, and means for effecting the rapid removal of the stuff.
Hindrances must be anticipated and avoided, and every facility established
for executing each division of the work quickly.
In order to treat the subject of rock-boring machinery with some degree
of clearness, reference will be made to the following heads :—
(a) Compressed air.
Engines and compressors.
Receivers and air pipes.
(d) Railways.
(e) Boring machines, stands, and frames.
(ƒ) Rock-boring machines.
(g) Boring tools or bits.
(h) Water and ventilating apparatus.
(i) Explosives.
(k) Electric blasting.
(7) Driving levels and sinking shafts.
(a) Compressed Air.-The only pressure fluid suitable for driving boring-
machines in close levels and shafts is that of compressed air.
The loss of initial power in effecting the compression of air is con-
siderable, this loss increasing with increase of compression.
When steam machinery is employed the loss may be apportioned thus :—
1. Loss of work in the form of heat radiating from the boiler and engine.
2. Loss of work in overcoming the vis inertia of the machinery and
friction induced in the moving parts of the engine and compressor.
3. Loss of work in neutralising the expansive effects of the heat occurring
in the compression of air.
In the use of compressed air, after it has been forced into the receiver,
other losses occur, viz. :-
4. From the friction of the air in the pipes employed for conveying the air
to the boring-machines, this loss decreasing with increase in the diameter of
the pipes.
5. In changing the movement of the boring-piston, which must neces-
sarily run at a high velocity.
At the Blanzy Collieries, Montceau-les-Mines, France, considerable atten-
tion has been given to the subject of compressing air with the view of
ascertaining the loss of power between the boiler and the boring-machines.
At that place two kinds of compressors are employed—one a Sommeiller, in
which the speed is slow, the valves large, the air compressed in contact with
water which fills the clearance spaces, and delivers the contents of the stroke
into the receiver; the other a Blanzy compressor, in which the piston speed
is comparatively high, the cylinder surrounded by a water-jacket, and the
cylinder-covers fitted with spray jets in connection with pumps by which
water is forced into the cylinder during the compression of the air. M.
Gralliot, the mechanical engineer to the establishment, selected the former
compressor for trial, and after a series of exhaustive experiments ascertained
in general terms that the work charged into the receiver in the form of com-
pressed air represented from 35 to 45 per cent. of the work due to the steam
within the boiler, while the work obtained through the medium of boring-
machines was only 20 to 25 per cent. of the boiler work. It therefore
follows that from four to five horse-power is required to afford one effective
CHAP. II.]
POWER BY COMPRESSED AIR.
509
horse-power in the boring-machines, and that the loss in transmitting com-
pressed air from the receiver to the machines, and in changing the movements
of the piston and its accessories, is from 15 to 20 per cent. of the power
generated within the boiler. In other words, the power within the boiler is
disposed of as follows:-
Loss, in transmission from boiler to engine, and overcoming resistances in engine
and compressor
•
0.65
0'55
Loss, in passing from receiver through transmission pipes, and in changing the
movements of the piston and its accessories
Effective power obtained in boring-machines
0.15
O'20
0'20
0.25
Total
I'00
1.00
•
The table confirming these general results, compiled by M. Gralliot, is
subjoined, the figures being mostly according to the French metric system :—
Pressure per square inch
Revolutions of engine per minute
Water injected into compressing cylinder
Temperature of water injected
Lbs.
621/
35/1/20
6321/2
10-II
IO-II
13.15
Litre
•560
•560
•560
Morn 71° Fahr., Even. [89° Fahr.
Work due to the steam used in steam-engines
Work absorbed by compressors
Kilos.
4361-60
3234·80
4460.00
3620.88
2575°44
4029'00
""
stored in receiver
""
Work absorbed by the friction of the machinery
Co-efficient of the useful effect of the steam
Work absorbed by compressor, divided as follows:
Work absorbed in compression of air
in expelling air
in expelling water
stored in receiver
•
Work lost by the heating of the air
Volume of air drawn in by stroke of piston
compressed at the ordinary temperature
Gross work produced by the steam
Effective work transmitted by the engines
""
Work transmitted to the levels, admitting that the
borers only return 60 per cent. of the effective
work
""
740*72
659.36
431.00
""
•83
•80
*90
""
1571.46
963.40
1655.64
422.60
271.76
788.40
""
25.46
13.75
25.45
1601.37
1326.54
1560.11
""
393.76
210*23
797.60
Cub, mètre
•
044 530
066•250
054'000
""
035*230
054'400
035.300
Horses
46.50
34.50
47.60
""
36.75
27.50
43.00
""
17.10
14'15
16.17
10.25
8.50
10'00
Proportion of available work of air to gross work of steam
Proportion of available work of air to actual work of steam
Proportion of actual work of air in machines to gross work
•
0.36
0'41
0*35
0'44
0.51
0.38
of steam
0.22
0.245
0.209
Proportion of actual work of air in machines to effective
work of the engine.
0.26
0.32
0.23
If air could be compressed without producing an increase of temperature,
its volume at any part of the piston stroke would be in inverse proportion to
that of the original volume.
For example, one cubic yard of air at a tension of one atmosphere would
be reduced to one-half of a cubic yard at a tension of two atmospheres.
As, however, the heat contained in the one cubic yard of air would remain
in the half cubic yard, it follows that the temperature of the latter volume
would be materially increased, and that such increase of temperature taking
place within a cylinder would cause a certain measure of resistance to the
piston; or, in other words, a "loss of work." To reduce this thermic
resistance to the compressor piston, various expedients are resorted to. In
one apparatus the air is compressed in contact with water; in another the
cylinder is surrounded with water; while in a third, in addition to the water-
510
[BOOK III.
PRACTICAL MINING.
jacket, a finely-divided spray of water is forced into the cylinder during the
time of compressing the air. The diagram, Fig. 99, shows the length of
TEMPERATURE
OF AIR
T.
d
PRESSURES IN LBS PER SQ IN
ABOVE THE ATMOSPHERE
lbs
e P
132-3
piston stroke AB
divided into ten
FAX
506-5
409-6°
428-5°
983-5°
330
200-0°
185-4°
.68° C
124-7°
CURVE__WITH INCREASE
OF TEMPERATURE
MARIOTT'S
CURVE WITILDECREASE OF TEMPIRATURE
DURING COMPRESSION
CURVE
PIRATURE DURINE EXRANSI.
d
A 1/10
2/10
4/10
STROKE
124-99
117-6 -8 ATMOS
110.25
LICZ ·9 -
95-55
.08.20
80-85
73 -5 — 0
66-15
58-8-
51-45
36-75
29-4-2
22-05
14-7-1
7-35
ATMOSPHERIC
LINE.
VACUUM LINK,
5/10
6/10
7/10
0/10
9/10
B
OF PISTON
Fig. 99.
D
parts, the atmo-
spheric line C D,
the curve of com-
pression Ce ac-
cording to Boyle
and Mariotte's law
(viz. that the vo-
lume of air is in
inverse proportion
to the original
volume at any
part of the piston
stroke), the curve
cd showing the in-
crease of tempe-
rature occurring
during
compres-
sion without the
presence of a cool-
ing medium, and
the curve de exhibiting the decrease of temperature consequent on release
and expansion of the compressed air.
The following table shows the increase of temperature and volume, which
result from the compression of a cubic metre of air, from one to eight atmo-
spheres, the air before compression being taken at 68°
of work due to such increase of temperature:-
Pressure
in Atmosphere.
Compression with
Temperature Constant,
Mariotte's Law.
Compression with Increase of
Temperature,
Duc to Heating of the Air.
Volume in
Cubic
Work
Foot Pounds. ture Fah.
Metres.
Volume
Tempera- in Cubic
Metres.
Work
Foot Pounds.
Excess of Work,
due to the Heating
of the Air.
Fah.; also the loss
Percentage
Loss of Work,
due to
Heating of Air.
I
12345678
I'000
0.500
0.333 82.137 267°
68°
1.000
51.571 186°
0.612
57.348
5.777
9.2
O'459
96.592
14'455
15.0
O'250 103.142 330°
0.374
128.238
25.096
19.6
0.200 119.873 383°
0.167 133.574 428° 0.281
0.143 144.877 470°
0.252
O'125 154.881 506° 0.229
0.320
153.341 33.468
21.3
175.761 42.187
24.0
195'557 50.680
26.0
213.415 58.534
27.4
On examining the foregoing table it will be seen that, according to the
law of Boyle and Mariotte, one cubic metre of atmospheric air, when com-
pressed to a tension of eight atmospheres, is reduced to a volume of 0.125
cubic metre, while if the compression is effected with increase of temperature,
and without loss of heat, it will measure for the same tension o°229 cubic
CHAP. II.]
BORING-ENGINES AND COMPRESSORS.
511
metre. The loss of work resulting from such increase of temperature is also
shown to be 27'4 per cent.
(b) Engines and Compressors.—Air compressors may be driven by means of
water-wheels, turbines, or water-pressure engines. As, however, the pressure
of water under a given head may be regarded as constant throughout the
stroke of an hydraulic motor, and the compression of air, commencing from
zero, increases in intensity until its delivery to the receiver begins, it is neces-
sary that the number of compressing cylinders and driving gear be arranged
and speeded so as to obtain from the constant power of the water its greatest
effect.
Steam Engines.-In some of the earlier compressing-machines motion
was transmitted from the engines to the compressing cylinders by means of
spur-wheel gearing. This arrangement admitted of a high velocity in the
steam piston, and of a comparatively slow velocity in the compressing piston ;
but it rendered the strain unequal on the teeth of the wheels, and sometimes
led to their breakage. The more recent practice is to set the cranks of the
air and steam cylinders in such a relation to each other that the maximum
effect of the steam may be exerted at the time that the air is being delivered
to the receiver, or to employ double steam and compressor cylinders, so that
the power of one steam cylinder may overcome the resistance offered by the
compression of the air in the opposite cylinder. In addition, it is sometimes
desirable to provide the engine with a variable expansion valve, and
to economise power, by using steam on the piston of considerable pressure,
five or six atmospheres, and cutting it off within the cylinder at from three
to five eighths of the stroke.
Compressors.-As soon as the compression of air was rendered necessary
for the production of power, inventors applied themselves to the arrangement
and construction of compressors which should offer some special advan-
tage. Sommeiller introduced at the Mont Cenis Tunnel a wet compressor;
Colladon, on behalf of the contractors of the St. Gothard Tunnel, arranged a
fast-speed " spray" compressor. In England the wet compressor is but
little employed. Fast-speed dry compressors have been mainly adopted,
perhaps on account of their comparative cheapness of cost. In Germany,
France, and Belgium the mining engineer seems to prefer the wet
compressor. Doubtless the latter apparatus is well adapted for mine work.
It bears a somewhat similar relation to the fast-speed compressor, that the
Cornish engine bears to the locomotive-viz. for its strength, durability, and
comparative slowness of speed. In another important item it also exhibits a
strong resemblance; it is an economical apparatus, since it may be contrived
to give the largest percentage of useful effect for the unit of power expended
to secure it. The essential difference between the wet and dry compressor
is, that the wet compresses the air by means of a column of water moved by
a piston, the dry by the piston itself, acting directly on the air without the
admission of water to the cylinder.
The speed of a wet compressor is limited to about 200 feet per minute. A
dry compressor is frequently driven 400 feet per minute, consequently
the piston area of the former would seem to require twice the area of the
latter to give an equal amount of work. As the cylinder of a wet compressor
512
[BOOK III.
PRACTICAL MINING.
will charge itself with 96 parts of the cubic contents of the stroke, while a
dry compressor only takes in from 70 to 80 parts, the economic result of
the wet compressor is greater.
Fig. 100 shows a vertical section of a wet compressor through the centre
I
T
T
P'
b
It t
Ե
ť
Fig. 100.
DO
of the cylinders. The
piston moves horizon-
tally in a cast-iron cy-
linder C, which is kept
full of water. At the
extremities of the cy-
linder are two vertical
columns, P' P, closed at
their upper ends. The
air is admitted through
a rectangular opening,
S, in the side of each
column. The intake
valves, S, are of leather,
stiffened with wrought-
iron plates, as in mine pump buckets. The discharge of the air into a
receiver takes place through gun-metal valves, s'. The movement of the piston
within the cylinder causes the water in the vertical columns, P′ P, to rise on one
side and fall on the other. Above the falling column of water the tendency
towards a partial vacuum causes the admission valve, S, to open and the
unoccupied space to be filled with air. When the piston returns in the opposite
E
ތ
**
C
A
D
Fig. 101.
E
direction the admission
valve closes, the water
is driven upwards, and
the air compressed until
its tension becomes the
same as that in the
receiver.
The outlet valve, s',
then opens, and as the
water rises through and
above the outlet valve,
it follows that the whole
of the air compressed is
forced into the receiving vessel by means of the pipe T. A small but adjusted
quantity of water is continually supplied to the compressor cylinders by
means of the pipe t and branches t't. The water is delivered first into the
receptacles b b, and then into the cylinders through the inlet valves. To
prevent any overflow of water from the receptacles it is drawn off by the
breeches and waste pipe, t'ť, placed at the bottom.
In this form of compressor, Darlington has introduced a spray of water
immediately under the outlet valves, s', so as to absorb a larger amount of
heat than would otherwise be effected by the simple contact of the air with
the vertical water-compressing column.
Fig. 101 is a sectional elevation of a compressor fitted with a water-jacket
CHAP. II.]
THE COLLADON COMPRESSOR.
513
and two spray nozzles. A, compressing cylinder; C, water-jacket cylinder
encasing the compressing cylinder; D, spray jet; E and E', inlet valves;
F F', outlet valves; G, pipe for admitting water to the jacket-cylinder;
H, eduction pipe.
The following are the principal dimensions of one of the compressors in use
at the Blanzy Collieries:-
Steam
Cylinder.
Diameter of piston 251"
Length of stroke 63"
Area of admission
valve in square
inches
Area of delivery
valve in square
inches
Speed of piston per
second
•
Compressor
Cylinder.
213"
63
59
48
4 ft.
4 tt.
The volume of air com-
pressed to 45 lbs. per square
inch at 25 revolutions per
minute is theoretically 450
cubic feet; taking the prac-
tical result at 80 per cent. it
amounts to 360 cubic feet.
Colladon Compressor.
This compressor (Fig. 102)
consists essentially of a hori-
zontal cylinder and a hollow
piston, the rods of which,
also hollow, pass through
both ends of the cylinder
covers. In each of these
covers are two admission and
one delivery valve. The dis-
tinguishing features of this
compressor are the means
adopted for the purpose of
absorbing the heat developed
during the compression of
the air, and for keeping the
various parts of the appara-
tus in a comparatively cold
condition. The cylinder is
surrounded by a water-
jacket, A. The piston and
piston-rods are provided
with internal chambers for
the reception and passage of
Fig. 102.
་་་་་་་་
AH
B
VANDIMIASA
\\EMINITRATE
07
water. Spray nozzles, J J, are also introduced into the cylinder. It is alleged
that the volume of water admitted to the cylinder and into the various parts
of the apparatus is so adjusted as to limit the temperature to 80° Fah. when
the pistons are running at 200 feet per minute, and compressing the air to
514
[BOOK III.
PRACTICAL MINING.
a tension of 90 lbs. per square inch. At the Airolo end of the St. Gothard
Tunnel twelve of these compressor cylinders were grouped in four sets of three
cylinders each. The three cylinders, set side by side, were driven by means
of a three-throw crank in connection with wheel-gearing and a turbine. The
dimensions of one of these compressor cylinders were, diameter of piston, 18
inches; stroke, 17 inches; inlet valves, two in each cylinder cover-total
area, 39 inches; outlet valves, one in each cylinder cover—total area, 101
inches; theoretical volume of air at 65 revolutions per minute, 1,027 cubic
feet, or compressed to 90 lbs. per square inch at 70 per cent. of the theoretical
volume, 119 cubic feet.
Carefully conducted experiments with a wet compressor erected at the
Saarbruck mines to supply rock-boring machines have been made with the
following results :-
No. of
Experiment.
One Atmosphere.
Useful Effect of the Compressor at
Two Atmospheres. Three Atmospheres,
I
O'94
0.88
0.85
2
o'95
0.885
0.855
3
O'93
0.88
0.85
4
O'95
0.90
0.865
0.94
0.87
0.83
6
0'93
0.85
0.80
Mean
•
0'94
0.877
0.84
Diameter of each piston
Stroke of piston
Anmu
Fig. 103.
One suction valve in each cover, internal diameter
5 inches
•
•
Two discharge valves in each cover, diameter
3 inches, equal 7 inches area × 2
Theoretical volume of air per stroke
Or, for the group of three cylinders
At a speed of 50 revolutions per minute three
cylinders will afford 4'14 × 50
Volume of air compressed to 50 lbs. per inch at
70 per cent. of the contents of the stroke
•
EGU
13 inches.
18
19.6 inches area.
•
14 inches area.
1.38 cubic feet.
4.14
207
3013
Three - Cylinder Com-
pressor.-At the Rushen
mines, Isle of Man, a
three cylinder air com-
pressor was erected for the
purpose of accelerating
the sinking of an engine-
shaft, and driving a main
level in the lode by means
of three Darlington Boring
Machines. Each cylinder
is single acting, the piston-
rods being connected with
a three-throw crank (see
Fig. 103). The cylinders
are fixed in a water tank,
while jets of water play
into each cylinder during
the compression of the air.
The inlet and outlet valves
are set in the cylinder
covers, the outlet pipe to
air receiver being in con-
nection with each outlet-
valve chamber.
The following particu-
CHAP. II.]
DRY COMPRESSORS AND AIR-PIPES.
515
lars relate to a vertical single-acting compressor, fitted with a water-
jacket and spray nozzles designed by Cornet: Engine, two vertical
cylinders, steam-jacketed, with Meyer's expansion gear. Cylinders, 16'9
inches diameter; stroke, 39'4 inches. Compressor, two cylinders, diameter
of piston 23'0 inches; stroke, 39'4 inches; revolutions per minute, 30 to
40; piston speed, 39 to 52 inches per second; capacity of cylinder per
revolution, 20 cubic feet; diameter of valves, viz. four inlet and four outlet,
5 inches; weight of each inlet valve, 8 lbs. ; outlet, 10 ĺbs. ; pressure of air,
4 to 5 atmospheres. The diagrams taken of the engine and compressor show
that the work expended in compressing one cubic metre of air to 4.21 effective
atmospheres was 38,128 lbs. According to Boyle and Mariotte's law it would
be 37,534 lbs., the difference being 594 lbs., or a loss of 1.6 per cent. Or if
compressed without abstraction of heat, the work expended would in that
case have been 48,158. The volume of air compressed per revolution was
0*5654 cubic metre. For obtaining this measure of compressed air, the work
expended was 21,557 lbs. The work done in the steam cylinders, from indi-
cator diagrams, is shown to have been 25,205 lbs., the useful effect being
85 per cent. of the power expended. The temperature of air on entering
the cylinder was 50° Fah., on leaving 62° Fah., or an increase of 12° Fah.
Without the water-jacket and water injection for cooling the temperature it
would have been 302° Fah. The water injected into the cylinders per revo-
lution was 0.81 gallon.
Dry Compressors.—The arrangement of the dry compressor is nearly
similar to that of the spray compressor. No water is introducod into the
cylinder for the purpose of absorbing heat developed during the compression
of air, but a water-jacket around the cylinder is usually relied upon for that
purpose. The result is so unsatisfactory that economy of power may be
said to be sacrificed to simplicity of arrangement.
The objections which may be urged against high-speed compressors are
(1) The rapidity with which heat is accumulated within the cylinder, over-
heating the various parts unless the heat is largely absorbed by means of
water; (2) Loss of air with metallic spring pistons, amounting to from 7 to
10 per cent. of the stroke, and increasing largely with low piston velocities;
(3) The voidance of air from the cylinder during the closing of the inlet valves,
in some cases a serious percentage of the contents of the stroke; (4) The
loss of useful effect of the steam consequent on any passage of air from
front to back of compressor pistons; (5) The rapid wear and tear of
parts incident to a high piston speed; (6) The liability of the valves to
"break up" the force or impact of the shutting blow, increasing with the
pressure multiplied by the square of the velocity. Against low-speed com-
pressors it may be alleged that the apparatus is large in proportion to the
power it will afford, and that the first cost, if distributed on the horse-power
of the compressor, is somewhat high.
(c) Receiver and Air Pipes.-The receiver and air-pipes should be of
sufficient capacity to run the boring-machines without exhibiting much
variation of pressure. The dimensions of the receiver, as well as the pipes,
ought therefore to be in relative proportion to the number of machines to be
worked, the cubic quantity of air necessary for running the machines during
L L
516
[BOOK IJI.
PRACTICAL MINING.
a given period, and to the charging power of the compressor. No exact rule
can be laid down for determining the dimensions of the receiver; but if its
capacity be eight or ten times greater than the volume of air required per
minute for the use of the machines, it will probably be sufficient.
Large receivers and air-pipes are desirable (Fig. 104). The boring-machines
when well supplied with air will not only deliver their blows more uniformly
and with the desired effect, but the friction in passing air through large pipes,
from the receiver to the machine, will be inconsiderable. The receiver may
be placed vertically, or lie horizontally on the ground, near to, or somewhat
distant from, the compressor. To render the receiver complete it should be
furnished with relief and stop valves, and, if in connection with a wet com-
pressor, a blow-off cock; and a pipe for returning water to the compressor
columns should be added, unless fresh water happens to be available for
cooling purposes. In such case the return pipe will not be required, but
instead the receiver should be fitted with an automatic arrangement for dis-
รา
Fig. 104.
charging the water when it may attain a given height within the receiver
itself.
Localities.
Mont Cenis
St. Gothard
Vieille Montagne
Saarbruck.
Marihaye
Ronchamp
TABLE OF RECEIVERS.
Designer
of Compressor.
Sommeiller
Colladon
Humboldt.
No. of
Receivers.
14
•
4
I
Contents.
28,000 cubic feet.
2,225
180
""
3
740
Sommeiller
6
4,250
""
do.
I
880
""
Anzin
do.
2
1,450
Minera
Darlington
I
200
Ballacorkish
do.
I
600
""
St. John del Rey
do.
2
•
400
Madonna
do.
I
200
•
Wheal Agar
do.
I
600
•
""
Moonta
do.
do.
2
""
Marbella
Compressed air must be conveyed in pipes from the receiver to the boring-
machines placed at various points underground. During this transmission a
loss of work is occasioned by the friction of the air. The results of numerous
experiments to determine the value of the loss thus occasioned show-1. That
CHAP. II.]
RAILWAYS IN MINE HEADINGS.
517
the resistance is directly as the length of the air main. 2. That it is directly
as the square of the velocity of flow. 3. That it is inversely as the diameter
of the pipe. The formulæ established from these results and conclusions
show that for air-pipes of the diameters usually employed, and for the dis-
tances prevalent in mines, the loss of motive force due to the friction of the
air in the main is insignificant when the velocity does not exceed 4 feet a
second.
The pipes to form the permanent main from the receiver to the boring-
machines may be of cast or wrought iron, but in either case they should be
provided with faced and scored flanges. Cast-iron pipes are obtainable in
6 or 9 feet lengths; wrought-iron pipes in 12, 14, or 16 feet lengths. If
wrought-iron pipes are to be used, cast-iron flanges may be screwed or
soldered on the ends. Before cast-iron pipes are placed in position the
interior surfaces should be well flushed with water and swabbed, in order to
remove any loose sand or scale adhering to the sides. To complete the
operation, the interior surface should be covered with a non-corrosive paint.
The inside of many a boring-machine cylinder has been partially destroyed
through neglect of these simple precautions. The pipe-joints are readily and
effectively made by means of a flat ring of vulcanised rubber. The expansion
taking place in an air main is best taken up by means of a running joint, or
by introducing a short bend of copper pipe. In the levels the main may be
laid on the sole, or hung on the side towards the roof, the latter being a
position frequently preferred. In some cases it will be useful to place one or
more cocks on the main; one fixed at the commencement of the "advance"
or terminal pipe is almost necessary. The advance pipe is in some instances
formed of one pipe sliding within another, the inner one being drawn out
as the forebreast of the level is advanced. To the end of this inner pipe
is attached the flexible hose for connecting the permanent main with the
boring-machines.
When tunnels have to be driven a long distance, and time is of the greatest
value, a reserve main is sometimes fixed to supply air to the borers, during
the period when additional pipes are being added to the principal or working
main. In metalliferous mines, rock-boring machines will scarcely be required
to operate at a greater distance than a mile from the seat of power, and as
the number of the machines will be more or less limited for some time to
come, pipes of less diameter will suffice than if the air is to be conveyed a
distance of 3 or 4 miles, as in the case of some tunnels already executed. For
the general main, pipes 3 inches to 4 inches diameter will be large enough;
for the secondary or branch part of the main, the diameter need not exceed
2 inches or 3 inches, whilst for branches from this part of the main, to con-
nect a series of three or four borers, the diameter may be reduced to 2 inches.
(d) Railways.—In tunnels or mine headings, driven in Europe, a single
railway is generally laid for the borer carriage, and waggons necessary for
the removal of the débris. In one or two instances the borer carriage has
been placed on a wide railway, and the stuff removed by means of waggons
running on a narrower gauge line. The advance headings in Europe scarcely
ever exceed a width of 9 feet. In America, however, the whole width of the
railway tunnel is sometimes carried in the advance heading, which renders a
L L 2
518
[BOOK III.
PRACTICAL MINING.
double and spare line of rails necessary. In driving mine levels, the gauge
of the carriage rails may have to conform to the gauge of the waggon
required for the removal of the stuff. If no special considerations were neces-
sary other than to determine the best gauge for the borer carriage, the gauge
might be fixed at 2 to 3 feet, and the weight of rails from 18 lbs. to 20 lbs.
per yard. In long headings, and where boring carriages are employed, it
may be desirable to cut stalls, at from 50 to 100 fms. apart, for the lodgment
of the carriage and boring-machines, during the time of blasting the shot-
holes and effecting the removal of the stuff. Such stalls will also be found
very useful for sheltering the men during the firing operation, for holding the
boring tools, machine oil, or, when electric blasting is employed, the appa-
ratus required for igniting the fuses.
Places.
Gauge of Single
'Railway laid in
Middle of Level.
Ft. in.
3 3/
3
3
Width of
Height of
Advance Heading. Advance Heading.
Mont Cenis .
St. Gothard, Göschenen
""
Airolo
Vieille Montagne.
St. Leonard's
Marihaye
Ronchamp
Anzin
Friedrichsegen
Blanzy.
Gothardbahn
Marbella
Cwmbran
Maesteg
Mustconetcong
Hoosac Tunnel
Portskewet
Minera.
Drybrook
Ballacorkish
Foxdale
•
Laxey
Dolcoath
Carn Brea
•
•
•
•
3
Area of Heading
in Square Feet.
Ft. in.
Ft. in.
Ft. in.
121
4
I II
I 7:
2
I
I II
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H
9 ΙΟ
86
81 7
8 IO
8
2
72 2
8
6
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6
7
7
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7 4
53 9
6 7
43
7 3
52
7 3
52
6
7 10
7
3
56 9
23323
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7
7
49
7
7
49
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7
7
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1 2 2 N
4 0
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27
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6 6
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35
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216 O
9
216
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64 O
7 3
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7
42
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7
45 6
7 6
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6
48
2 9
8 6
72 3
(e) Stands and Frames for Boring Machines.-The economic result obtain-
able from the application of rock-boring machines is greatly dependent on
the form and strength of the stand or frame which may be employed to carry
the machines. If a drill is to deliver its blows to the bottom of a hole, in a
thoroughly effective manner, it must not vibrate and be deflected, as it were,
to any appreciable extent from its axial line, nor should the tool react without
giving the full effect of its impact to the stone. A frame, to be satisfactory,
must be sufficiently rigid to withstand the reactive twisting effect consequent
on the rapid reciprocation of the machines; it must also be constructed
so as to admit of being fixed and removed quickly; and afford the widest
range possible for directing the drills to various parts of the forebreast, or
for angling the shot-holes to such an extent as to ensure, by means of the
explosive, the removal of the rock.
Moreover, the stand or frame should be contrived so as to allow ample
space for the workmen to move around and to get access to the machines,
when the latter are at work.
CHAP. II.]
STANDS FOR BORING-MACHINES.
519
The several distinctive frames which have been constructed are, the Mont
Cenis, which carried ten drills, and weighed eighteen tons; the Dubois-
François, mounted with six drills, weighing from three to four tons; the
Beaumont "Camel," of considerable weight, carrying four machines; and
the Darlington stand, three hundredweight, for carrying two machines.
Mont Cenis Stand.-This stand, consisting of a framework of wrought iron,
was 24 feet long, about 6 feet wide, and 6 feet in height. It ran on four
wheels, and carried the boring-machines, air-pipes, and a vice for effecting
any small repairs required to the boring tackle during the boring operation.
When in working position the wheels of the stand were lifted from the rails,
so as to obtain the entire weight of the apparatus for the purpose of resisting
the percussive action of the machines.
Dubois and François Stand.-These stands, used in mine levels, are
arranged to carry two or four machines. The length of a stand mounting
four machines is 10 feet, height from rails 3 feet, width outside of rails 3 feet.
The frame of the stand is of wrought iron, and includes four screw-cut
columns; viz. two to which the machines are attached, and two, distant
about 5 feet, which are provided with loops for supporting the front ends
of the machines. The stand is mounted on six wheels, each about 9 inches
diameter. These wheels are so placed in relation to the weight of the frame
and the position of the machines as to allow the latter to drop, so as to angle
close to the bottom of the level. Each machine is connected by means of a
short hose pipe to a small air reservoir, fixed near to the top of the frame.
When the machines are at work the stand is lifted by means of screws which
bear on the surface of the rails; the dead weight of the stand is consequently
obtained and utilised in resisting the impact of the machines when these are
at work.
1
Ս
Y
Beaumont's Camel.—The Beaumont camel is composed of a trolley, fitted
with a vertical column, four arms, two extending each side of this column,
and a small air and water reservoir set at the rear end of the trolley platform.
The trolley is mounted on four wheels, each 10 inches in
diameter and 4 feet apart. These wheels run on a 2-feet
gauge railway. The width of the trolley platform is
2 feet; the diameter of the vertical column, 15 inches;
height from face of rails, 6 feet; diameter of horizontal
arms carrying the boring-machines, 8 inches. The central
boss holding the two arms is fitted with an hydraulic
pump. In each arm is an hydraulic ram. To fix the
arms for boring purposes the outer ends of the rams are
pressed against the sides of the levels. In this stand its dead weight is not
required for the purpose of keeping the boring-machines in line of the shot-
hole. A diagrammatic illustration of this stand is shown in Fig. 105.
Fig. 105.
Darlington's Stand.-This stand, employed for driving mine headings, is
composed of a vertical and two horizontal bars. The vertical column is
clamped to the roof during the boring operation; the side bars are set so as
to require but once shifting to bore the whole number of holes. In order to
use this stand with ease and facility it is taken to and from the forebreast on
a small trolley arranged for that purpose.

520
[BOOK III.
PRACTICAL MINING.
This trolley is also fitted with a platform for holding the boring-machines
as well as an air cylinder, having one inlet for the air main, and
two outlets, one connecting each machine by means of a short piece of
rubber hose. The arrangement of the stand is such as to admit of boring
الد
4831
Fig. 106.
4142
the holes, and blasting the ground, in vertical or horizontal "cuts," as may
be desired.
Fig. 106 represents a vertical side elevation of the trolley, clamping
Fig. 107.
Jo!
column, machine arms, and boring-
machines. The column is shown
attached to the trolley; but before
the machines are set to work it is
disconnected, and the trolley shifted
a few feet to the rear. This separa-
tion of the trolley from the column
allows the workman to pass freely
from one side of the column to the
other. When the stand is with-
drawn, it is detached from the top
and sides of the level, clamped to
the trolley, and dropped, so as to lie
at an angle of about 45° to its ver-
tical position.
Fig. 107 represents a front eleva-
tion of the stand without the trolley,
the boring-machines in working
position, and the position of holes supposed to be bored. To drill these holes
the upper and lower arm is unclamped once during the boring shift, turned
and clamped to the opposite side. These operations, together with the
angling and traversing range of the machine, suffice to secure the requisite
positions for drilling the whole of the holes.

CHAP. II.]
SEVERN TUNNEL BORER STANDS.
521
Fig. 108 shows the stand and trolley at the end of a level. In this view
the boring-machines, horizontal arms, air cylinder, and rails, are illustrated.
The method of boring the holes from a fixed point on the bar, simply by
angling the machines, is also rendered apparent. To use two machines
three men are necessary; viz. one man to each machine, and one man
between the machines at the forebreast to change the tools, oil the piston-
Fig. 108.
rods, direct the bits on commencing the holes, and to supply the holes with
water.
The general form of the stand used at the Severn Tunnel, Portskewet,
and which carried two Geach boring-machines, is shown in Fig. 109. The
platform trolley was provided with a vertical bar 5 feet long, to which was
-.8.0---
Fig. 109.
Џ
Ų
Ų
보
​ก
ñ ñ
Fig. 110.
Fig. 111.
attached a horizontal arm. To fix this bar it was screwed to the top and
bottom of the heading. The machines were clamped at A A', about four feet
from the sole of the level. The holes were bored by radiating the machines
from these points.
Figs. 110 and 111 are diagrammatic illustrations of stands employed in
France for carrying four and six boring-machines. In the first of these two
machines are supposed to be over and two under the bar, while the second shows

522
PRACTICAL MINING.
[BOOK III.
the position of four machines over and two under the bar. These bars, together
with the machines, are so placed as to admit of the perforation of the fore-
breast without altering their normal positions. In Fig. 109 one machine
commands one quarter of the area of the forebreast; in Fig. 110 one machine
deals with one-sixth part of the area of the face.
Shaft-sinking Stand.-The stand, introduced at the Minera mines, North
Wales, in 1876, is shown in Fig. 112. It consists of a vertical bar 18 feet
long, and two arms, the length of which is dependent upon the diameter of
the shaft. For the Darlington boring-machines the arms are set 3 feet from
the bottom of the shaft, the arms are clamped to the sides of the shaft, and
Fig. 112.
the boring-machines worked and shifted
on the arms, so as to bore the holes
shown in the illustration. When the
whole number of holes are drilled the
horizontal bars are unclamped, the ver-
tical column loosened from the stay piece
of timber, which at first is 6 feet from the
bottom of the shaft, and the apparatus
lifted 20 or 30 feet.
When the shaft bottom is cleared, say
to a depth of 3 feet, for a second boring
shift, the bar is dropped to the bottom,
and clamped to the stay piece, this time
9 feet from the bottom. Four sinks, each
3 feet deep, can thus be made before it
will be necessary to place a second clamp-
ing or cross-piece within 6 feet of the
bottom. At the Ballacorkish mine, in
the Isle of Man, a pump 8 inches diameter
was made the central sinking column.
This pump was provided with a wind-
bore of cannon - like strength, around
which two horizontal arms rotated. Each
arm carried a boring-machine. About
12 feet from the bottom of the shaft a
wrought-iron pent-house, provided with
doors, encircled the pump, and protected
the men who worked underneath.
The "lift," at first 12 fathoms long, hung to screws 14 feet long, was so
arranged as to discharge the sump water through a nozzle piece, one of which
was placed in the column, at distances 18 feet apart. The pump-rod was
arranged to slide on a "set-off" attached to the main rod, so that both pumps
and rods were "dropped" together.
The whole was arranged and placed in the shaft previous to the com-
mencement of the sinking operation.
(f) Rock-boring Machines.-The first inventor of a rock-boring machine
seems to have been Trevithick. In the year 1813, when his attention was
directed to the subject, Cornwall was not only the chief seat of our mining
CHAP. II.]
MOVEMENT OF BORING TOOLS.
523
industry, but, through the startling improvements effected in the steam-engine
by Watt, Murdoch, Trevithick, Woolf, and others, an impetus was given to
mechanical inventions which extended far beyond the confines of the county,
and men were stimulated at home and abroad to substitute as far as possible
mechanical appliances for manual labour. Some forty years, however,
passed away before the idea of boring shot-holes, by means of machinery,
was rendered practicable. The exigencies of the Mont Cenis Tunnel
induced Bartlett to devise a steam rock-boring machine. Later Sommeiller
invented the machine which bears his name, and showed how it could be
worked by compressed air. Following Sommeiller's success, in the Mont
Cenis Tunnel, Italian, German, French, Swedish, American, Australian,
and English engineers addressed themselves to the subject of inventing,
contriving, and improving rock-boring appliances. Machines 10 feet long,
beset with complicated gear, are now replaced by machines 3 feet long,
presenting little more than the cylinder, valve, and forwarding screw. All
real and permanent improvements have tended in the direction of increased
strength and simplicity of parts. In more particularly tracing the develop-
ment of inventors' ideas for expediting tunnelling and mining operations, it
will appear that they group themselves into:-1, forming the shot-hole
by a revolving drill, and blasting the hole itself; 2, removing the entire
area of the heading without the use of an explosive, either by means of a
huge percussive, or a pressure cutting-machine; 3, boring shot-holes by
means of a small percussion-engine. The failure of the first method, that of
employing an ordinary steel tool in hard silicious rock, was soon rendered
apparent; the tool, instead of abrading the stone, was almost immediately
destroyed. The second method-substituting mechanical for mechanical
and chemical force, also proved objectionable when applied to hard
crystalline rocks. Apart from such machines, blocking as it were the
forebreast, the mechanical power required for performing the work was not
only excessive, but the progress slow, and the greatest difficulty experienced
in keeping the tools in condition for doing their work. The third method-
the use of percussion borers in combination with strong explosives, is
the one which has been, and is likely to be, attended with permanent
success. In perforating a heading with the requisite number of shot-holes,
only a minimum expenditure of mechanical power is required; the chief
work, that of removing the rock, being effected by powder or dynamite. In
a percussion borer the movements required to form a hole are of a threefold
character—1, a reciprocatory movement of the piston and tool to disintegrate
the rock; 2, turning the piston and tool during the reciprocatory movement;
3, advancing the tool as the hole is deepened.
In some rock-boring machines these movements are automatically
performed, and such automatic movements are desirable when four
or six machines are worked together; but the forwarding or advance
movement will be liable to fail in its object unless the rock be of uniform
structure and hardness. In other boring-machines the automatic movements
are confined to the reciprocation and rotation of the piston, while in some,
the piston and tool are rotated by hand. When only a single boring
machine is in use, a merely reciprocatory movement may suffice, but the
524
[BOOK III.
PRACTICAL MINING.
rejection of a simple automatic arrangement for rotating the piston and tool
is by no means desirable. In many cases the object of an inventor has been
to make his machine light, and of small dimensions. As the miner has
greatly encouraged the idea of employing a light machine, it may be
observed that this condition, in itself, has rendered light machines all but
useless for practical work, and enabled the miner to cite instances of failure,
where success could hardly have been expected.
To perforate a face of rock quickly several conditions must be observed:
-1. The machines must perform their work with certainty. 2. The number
of machines should bear some general relation to the area of the face. 3.
Stands are requisite for carrying the machines, not only as a means to keep
the "bit," in the line of the hole, but to admit of angling and shifting the
machines quickly.
Further, the use of stands will permit the workmen to exercise much
freedom in their movements, and enable machines to be employed which
will bore deep holes without changing the tool. Boring-machines of
the ordinary form drill the shot-holes in the same way as the common hand
borer. The borer is attached directly to the piston-rod and reciprocates with
it. The piston and rod constitute as it were a part of the boring tool, and
the movement as well as the blow is obtained either by admitting or
exhausting the pressure fluid to the front and back of the piston, or by the
maintenance of a constant pressure on one side of the piston only and
admitting or exhausting the pressure fluid from the other side. Most inventors
adhere to the ordinary method of moving a main piston and use a valve for that
purpose, but Darlington dispenses with a valve and distributes the pressure
fluid by means of the piston and portways in the cylinder. He also obtains
the reciprocating movement and blow either by keeping a constant pressure
of air on the upper or under side of the piston, and admitting and exhausting
the air from one side only. This arrangement enables him to make a
very simple, durable and effective machine. In order to rotate the piston
and tool to a certain extent during the back stroke of the piston, the rifle
bar, nut, and ratchet-wheel designed by Jordan and Darlington at the end of
the year 1865, and patented by them in 1866, is employed in most of the
machines in use. The advance of the boring cylinder and tool, as the hole is
deepened, is generally effected by an ordinary screw running in a nut attached
to the cylinder.
The Darlington Rock Drill consists essentially of only two parts, the
cylinder with its cover and the piston with its rod. The cover when bolted
on forms a part of the cylinder; the piston-rod is cast solid with the piston,
and is made sufficiently large at its outer end to receive the tool. These two
parts constitute an engine; and with less than one fixed and one moving
part, it is obviously impossible to develop power in a machine by the action
of an elastic fluid. The piston itself is made to do the work of a valve in the
following manner :-The annular space affording the area for pressure on
the fore part of the piston gives a much smaller extent of surface than that
afforded by the diameter of the cylinder (see Fig. 113), and it is evident that
by increasing or diminishing the diameter of the piston-rod, the area for
pressure on the one side of the piston may be made to bear any desired pro-
CHAP. II.]
THE DARLINGTON ROCK DRILL.
525
portion to that of the other side. The inlet aperture, or port X, being in
constant communication with the interior of the cylinder, the pressure of the
fluid is always acting on the front of the piston; consequently, when there is
no pressure upon the other side, the piston will be forced backwards in the
cylinder. During this backward motion the piston first covers the exhaust
port D, and then uncovers the equilibrium port
C1
A
-Н
A
D
Y, by means of which communication is esta-
blished between the front and back ends of the
cylinder, and consequently the fluid is made to
act upon the upper side of the piston. The
area of the back face of the piston being greater
than that of the front face, by the area of the
piston-rod, the pressure upon the former first
acts to arrest the backward motion of the
piston, which, by its considerable weight and
high velocity, has acquired much momentum,
and then to produce a forward motion, the pro-
pelling force being dependent for its amount
upon the difference of area on the two sides
of the piston B. As the piston presses down,
it cuts off the steam from the back part of the
cylinder and opens the exhaust. The length
of the piston is such that the exhaust port D
is never open to its front side; but in the for-
ward stroke it is open almost immediately
after the equilibrium port is closed, and nearly
at the time of striking the blow. The quantity
of fluid expended in this single-acting machine
is only that which passes to the back end
of the piston, since that which is used to effect
the return stroke is not discharged.
second form of the drill the pressure fluid is
kept constantly on the top of the piston and
exhausted from the underside. The distribu-
tion of the pressure fluid is effected by means
of the piston and portways in the cylinder,
precisely similar to the drill in which the
pressure fluid is kept continually on the
underside of the piston. Other forms of
single-acting drills have been devised by Dar-
lington, such as exhausting the pressure fluid
through the piston and piston-rod, and by
means of annular spaces in the piston keeping
the induction and exhaust portways and passages in the cylinder. In a
double-acting drill, instead of keeping the pressure fluid continually against
the smaller surface of the motive-distributing piston, the pressure is alter-
nately admitted to, and exhausted from, both sides of the piston. To effect
this the piston is made sufficiently long to admit of a groove being turned
In a
A
Fig. 113.

526
[BOOK III.
PRACTICAL MINING.
in it of such a length as to always be in communication with the pressure
portway formed about the centre of the length of the cylinder. Two induc-
tion passages and two exhaust portways are also cast in the cylinder. The
motive piston, in its passage across the portways, admits the pressure fluid to
one induction portway communicating with one end of the cylinder, and at the
same time it uncovers one exhaust portway and releases the pressure from
the opposite end of the cylinder. The objects gained by the foregoing method
of obtaining reciprocatory motion for rock-boring machines are (1) There
is only one working part used in obtaining the motion of the solid piston
and rod, which cannot well be destroyed by the effect of rapid and heavy
blows given to the boring tool. (2) Great rapidity of motion and efficiency
RIMBAULT
Fig. 114.
Fig. 115.
of blow are obtainable by means of large portways and passages, which can
be advantageously employed. (3) The speed, weight of blow, and length of
piston stroke can be varied at the will of the operator. (4) Stoppages due
to displacement of valves cannot occur: while with constant pressure main-
tained on the piston, the piston can never be in equilibrium, but it must
start at any part of the stroke. Fig. 114 shows a single-acting cradle-drill
mounted on a stretcher-bar for sinking shafts. In this drill the cylinder is
forwarded in the cradle, as the shot-hole is deepened by means of the
handle and screw attached to the cradle. Fig. 115 illustrates a double-
acting drill in which the cylinder works in a nut attached to the clamp.
This cylinder is advanced or withdrawn from the shot-hole by means of a

CHAP. II.]
BORING TOOLS OR BITS.
527
hand-wheel or handle at the top. Fig. 116 shows a single-acting drill
mounted for quarry work. In order to keep this drill firmly in position.
during the boring operation, heavy weights
are placed on the legs.
Among the results obtained by the use
of these machines, those connected with the
sinking of an engine-shaft at Ballacorkish
mine, Isle of Man, may be noticed. Rock,
tough Clay - Slate enclosing strings of
quartz: diameter of shaft, 10 feet; area,
86 square feet; depth of shaft from surface,
50 fathoms; number of shot-holes bored
in bottom of shaft, 22 to 24; diameter of
holes, 1 inch; depth of shot-holes, 3 to
5 feet; number of boring-machines em-
ployed, 2; pressure of air required, 50 lbs.
to 55 lbs. per square inch; number of men
employed, 9; lineal depth sunk weekly,
12 feet; time occupied in boring the holes,
21 hours; in charging and blasting the
shot - holes, 12 hours; in hauling the
stuff, 73 hours; total, 106 hours; to
which must be added, dropping the pump-
work, 10 hours; hindrances, 11 hours:
together, 21 hours. The following are
the relative results attending the sinking
of this shaft by hand, and by hand supplemented by machine labour:-
Fig. 116.
Contract price
Compressing air
Number of men employed
Lineal depth sunk per week.
Hand Labour.
Hand and Machine Work.
£ s. d.
31 O O
£ s. d.
13 0 0
Wages earned weekly per man
I
31 O O
14 O O
12 .
9
24 feet
18s.
12 feet
45s.
(g) Boring Tools or Bits.-The piston or tool holder of a rock drill is
generally rotated by means of a spiral bar running within the piston.
The length of the rotating movement will depend upon many circum-
stances, notably upon the angle given to the spiral bar, on the length of
stroke, and on the velocity of the piston. Some pistons will therefore rotate
to a greater extent than others, stroke for stroke. This result, together with
the fact that rocks are of varying degrees of hardness, frequently fissured,
presenting joints and faces to the point of the tool, have brought into use
bits of various forms. The flat, cross, X, and Z shape bits are, however,
chiefly employed. The flat bit is perhaps best adapted for drilling hard,
compact rock; the cross and X bits for jointy and fissured rock; the Z-shaped
bit for drilling holes in soft rocks, such as slate and shale, Fig. 117.
In ordinary mine headings, and in the employment of comparatively
small boring-machines, the diameter of the boring steel may vary from
528
[BOOK. III.
PRACTICAL MINING.
inch to 1 inch. All boring tools should be straight, and be as it were a
true prolongation of the axial line of the piston. A crooked or eccentric
tool will not only lessen the effective working of the machine, but it will
often cause such an amount of friction by rubbing on the side of the hole as
to bring the piston to a state of rest. In changing a tool care must be taken
that the cutting edge of the one to follow is not wider than the cutting edge
of the tool withdrawn. In the tool withdrawn it will be often found, owing
to the vibration of the machine, that the corners have been partly removed;
the cutting edge of this tool is therefore that portion not rounded, or that
which is parallel to the face of the hole. Many instances occurred in the
rudimentary stages of
boring when machines.
were alleged to be use-
less; the fact having
been that the cutting
edge of the second tool
was wider than that
of the tool withdrawn,
which tool, forced into
a tapered hole, neces-
sarily wedged itself fast,
thereby stopping or re-
tarding the working of
the machine. As a
common rule, the width
of the different sets of
boring tools at their
cutting edges should vary about of an inch from each other; but if the
rock should be unusually hard and the corners of the bit readily removed,
the difference between the widths of the bits should be greater.
++-
Fig. 117.
Flat Bit. Cross Bit. X Bit.
Z Bit.
Warsops Bit,
for making
round holes.
No rule can be strictly laid down for determining the time and power
requisite to bore holes of different diameters; but experience seems to show
that if a hole 12 inches deep and 1 inch diameter takes four minutes, a hole
2 inches diameter and of like depth, bored with the same machine, and
under the same conditions as to pressure of air and number of strokes per
minute, will take sixteen minutes. In other words, the machine and pressure
of air being the same, the time and power required to bore holes to a given
depth are as the squares of their diameter. The degree of temper to be
given to the bit when sharpened must be suited to the hardness of the rock
to be penetrated. Straw-colour is generally desirable when the tool has to
operate on very hard rock, and light blue when the rock is only of moderate
hardness.
(h) Water and Ventilating Apparatus.-In boring shot-holes, particularly
deep ones, in clayey or "sticky" rock, it is necessary to remove the dis-
integrated sand or clay as it may be produced. If this is not done the
stuff will "bind" so firmly as to wedge the "bit" fast, and thereby stop
the progress of the boring. An apparatus employed for the purpose of
washing the stuff from the holes consists of a cylindrical vessel mounted on
CHAP. II.]
EXPLOSIVES FOR BLASTING.
529
a trolley, which usually stands behind the boring-frame. By applying the
air pressure to the surface of the water, and extending a pipe from the
bottom of the water within the vessel to the forebreast, a stream of water
may be projected to any hole. To regulate the flow a small cock should be
fixed on the nozzle pipe. A simple method for obtaining the water is to
connect a small pipe an inch diameter to the pump work, to give the water
a head of 20 or 30 fathoms, and to apply the water to the holes by means of
a flexible tube and nozzle piece attached to the end of a small hydraulic
main.
The rate of boring a dry and wet hole is found to vary from 1 dry to 1'5
wet. A plentiful supply of water will in most cases not only quicken the
rate of boring, but it will economise the use of power to a proportionate
extent.
(2) Explosives.—Explosives for blasting purposes may be divided into two
classes, viz. :—
Slow, or rending compounds, as (a¹) ordinary black powder.
Quick, or shattering compounds—
(62) Nitro-glycerine.
(c³) Dynamite.
(d) Nitrated gelatine.
(e) Lithofracteur.
(f) Cotton powder, or tonite.
(a¹) Blasting powder is a mixture of saltpetre, sulphur, and charcoal.
In a good powder the grains must be firm, hard, dry, free from dust, not
ready to absorb moisture from the air, of uniform colour, and a small portion,
when ignited on white paper, should not burn it.
An analysis of seven different kinds of blasting powder, according to
Rziha, gave the following average results :-
Saltpetre
Sulphur
Charcoal
•
Hygroscopic moisture
63.33
15.89
•
19.39
1.36
99'97
Powder may be ignited by impact, but with great difficulty. It is, how-
ever, readily fired by the application of burning tinder or yarn, a steel or
platinum wire rendered red hot, by an electric current, or by fulminating
powder in contact with an electric spark.
Its specific
(b2) Nitro-glycerine is a light yellow, clear, oily liquid.
gravity is about 16; when transparent it freezes at a temperature varying
from 39° to 46° Fah. It is dissolved with difficulty in water, but readily in
pyroligneous spirit or alcohol, the solution being non-explosive. Pure
nitro-glycerine will not spontaneously decompose at an ordinary tempera-
ture, but if it should be associated with free acid, decomposition is apt to
occur. At 320° Fah. red vapours are evolved, and at 356° Fah. its exploding-
point is reached. The gases evolved on explosion are—
Carbonic acid
Binoxide of nitrogen
Nitrogen
•
•
45.72
20.36
33.92
100'00
530
[BOOK III.
PRACTICAL MINING.
The temperature of the gas at the instant of the explosion of nitro-
glycerine is placed by Trauzl at 839.9° Fah.
(c³) Dynamite was patented by Nobel in May, 1867. The highest, or
No. 1 quality, consists of 75 per cent. of nitro-glycerine and 25 per cent. of
an infusorial earth, known as kicselguhr. Dynamite is divided by the
Rhenish Dynamite Company into three classes—
No. IA, containing 75 to 77 per cent. of Nitro-glycerine and 25 to 23 per cent. Kieselguhr.
I
II
""
""
70 71
60 61
""
,,
""
""
""
30,, 29
40,, 39
No. IA is applicable to the hardest and most resisting rocks, such as
quartz, porphyry, and basalt, as also to the removal of ground in small
headings.
No. I. may be used for similar classes of rocks when less resistant, and
in levels of large sections, also in blasting Limestone, gneiss, and Granite.
No. II. is adapted for all sorts of soft rocks, and is well suited for assist-
ing No. IA quality dynamite, by placing the latter at the bottom and the
former upon it in very deep holes, or for the removal of the "side cuts'
after the "centre cut" is blown out.
وو
The safety of dynamite is alleged to lie in its soft, mealy consistency,
constituting, as it were, a cushion, a physical condition of great importance
in lessening the chance of its exploding when somewhat roughly handled.
At a temperature of 46° Fah. dynamite hardens into a mottled whitish sub-
stance. When frozen it cannot be readily fired. In a pulverulent condition it
can be more easily exploded, although with diminished violence, than when
fired in a pasty state. The firing-point of dynamite is 356° Fah. If ignited
it burns slowly, evolving fumes of a deleterious character. When instant
and complete combustion is effected by detonation, the gases evolved are
innocuous; but if the dynamite should be only partially detonated, hypo-
nitric fumes will be given off, offensive to the miner, and deleterious to his
health. Nobel on this subject has remarked: "The frequent occurrence of
bad fumes in mines only proves that dynamite is injudiciously used. The
general mistake consists in not securing carefully the detonation cap to the
fuse, and especially the fuse to the cartridge. In charging, the miner, under
such circumstances, easily draws fuse and cap out of the cartridge, leaving
them separated, so that the cap cannot possibly exercise its detonating
effect. What then takes place is this: part of the dynamite burns, emitting
hyponitric fumes, and part generally explodes under the influence of accu-
mulating heat and pressure. Thus the charge goes off, but with a far
inferior effect as compared to that of a proper detonation, and with the
emission of a great quantity of red fumes of hyponitric acid." No. 1 dynamite
is estimated to be about six times stronger than black powder in its effective
or shattering force.
In reference to this explosive, Drinker observes: "It is unquestionably
a safer material to transport, handle, use, or store than black powder. To
explode it heat and strong percussion are necessary."
While Nobel in effect states: "There are no accidents on record due to
its spontaneous combustion in mines. Local accidents are almost exclu-
sively to be attributed to injudicious thawing of nitro-glycerine preparations,
CHAP. II.]
NITRO-GLYCERINE COMPOUNDS.
53!
to reckless removal of the tamping in bore-holes after a misfire, and to the
careless handling of detonators. That comparative immunity from accidents
is due to safety from fire where small quantities are dealt with, and to
the absence of danger in loading bore-holes, since it is useless to ram the
tamping.
(d) Nitrated Gelatine.—It is found that a comparatively small quantity,
6 to 8 per cent., of a nitrated cellulose, prepared from cotton in a peculiar
manner, has the property of transforming nitro-glycerine into a gelatinous
explosive. Gelatine may be formed of-
Nitro-glycerine
Soluble gun-cotton
Camphor
86.4
9.6
4.0
100'0
The specific gravity of this material is 16. Its alleged characteristics
are-
1. It may be preserved intact for an indefinite length of time.
2. It fails to give off nitro-glycerine even under extreme pressure.
3. It is unaffected by violent shocks or vibration.
4. It is not affected dangerously by fire, but burns quietly and without
explosion.
(e³) Lithofracteur is a nitro-glycerine compound.
According to Ulex, chemist of Hamburg, who analysed a sample, it
contained-
Nitro-glycerine
Nitrate of barium
Coal dust
Infusorial earth (Kieselguhr)
•
70 parts.
5
"
2
23
""
100
Trauzl states that lithofracteur explodes at 248° Fah., and is more
sensitive to variations of temperature than ordinary dynamite.
(f) Cotton Powder or Tonite.-This explosive, known as tonite, is a nitrated
gun-cotton, produced in a granulated form, and compressed into cartridges
of various dimensions to suit the miner's requirements.
When highly compressed its density is nearly equal to that of dynamite.
Slowly heated, its firing-point is said to be 360° Fah.; when suddenly
heated, it is 482° Fah. One of the products arising from the combustion of
this explosive is carbonic oxide, a highly noxious gas. The relative power
of various explosive substances, when compared bulk for bulk, is given by
Nobel as follows:-
Nitro-glycerine
Dynamite (No. 1)
Lithofracteur
Gun-cotton
•
Curtis and Harvey's blasting powder, fired by detonators .
100
74
53
45
17.5
Fulminate.-The readiness with which fulminate of mercury may be
fired makes this salt an excellent medium for effecting the explosion or
detonation of other substances, such as pure gun-cotton, dynamite, and
nitro-glycerine compounds. Properly-made fulminate detonators are per-
fectly safe; and as their cost is but small when compared to the cost of a
M M
532
[BOOK III.
PRACTICAL MINING.
bore-hole and the requisite blasting material, none but the best detonators
should be employed. Mistaken economy, or carelessness in using unreliable
detonators, are errors almost fatal to the attainment of a quick rate of
advance, either in a level or a shaft. Some of the characteristics of fulminate
of mercury are: it explodes violently when struck or heated to 367° Fah.,
or when touched either with strong sulphuric or nitric acid, also when in
contact with the electric spark.
Detonation. To the researches of Roux and Sarrau is chiefly due the
light thrown on the possibility of producing two kinds of explosion in the
same substance-one by the application of heat and percussion, the other by
flame-heat.
Heat and percussion are produced in an explosive by the ignition of
fulminate of mercury, which in itself possesses a detonating quality.
Detonation may be defined as the instantaneous decomposition of an
explosive. When gunpowder is fired in the usual manner, combustion takes
place, each grain burning from the surface inwards; but when nitro-
glycerine compounds are ignited by means of fulminate of mercury, the mass
explodes simultaneously, or nearly so. In one case the rupturing force may
be said to be gradually developed, in the other instantaneously produced.
The following table, by Roux and Sarrau, gives the relative strength of
three well-known explosive compounds when simply fired and detonated :—
Gunpowder
Gun-cotton
Nitro-glycerine
Simple
Explosion.
Detonation.
1'00
4.34
3:00
4.86
6.46
10.13
Relative Weight
of Gases.
0.414
0·850
0.800
From the foregoing figures it will appear that an enormous instantaneous
force is gained by detonation over the simple explosion of either of the
compounds enumerated; while a brief consideration of the general facts
already adverted to will suffice to show that if high speeds in levels or shafts
are to be obtained by means of boring-machines, the strongest explosives
must be employed and detonated, so as to dislodge the rock under all the
conditions in which the bore-holes may be placed, and that it will be
desirable to shatter the rocks into fragments for effecting their immediate
removal.
Detonators.-Detonators are now so well known as to render any
description of them unnecessary. Dynamite may be completely detonated
by means of a treble detonator, if uniformly plastic. On the other hand, if
hard, or if it should present a mottled appearance, a quintuple detonator
may fail to effect the object of complete detonation.
(k) Electric Blasting.—A series of shot-holes charged with dynamite may
be simultaneously fired by means of high or low tension electricity. High-
tension electricity is obtained by a frictional or dynamo-electric machine;
low-tension electricity by a galvanic battery, or low-tension exploder.
In employing high-tension electricity it is necessary that the leading or
positive wire should be well insulated, otherwise a serious leakage of the
electric charge is apt to occur, especially if the wire should happen to be in
contact with the earth, or with any conducting material.
For the conveyance of low-tension electricity the insulation of the leading
CHAP. II.]
BORNHARDT'S FRICTIONAL-MACHINE.
533
or positive wire need not be perfect; but the copper forming this wire
should be of comparatively large section.
In the use of high-tension electricity the line resistance upon the current
is but small; consequently, with a well-insulated wire, most of the electricity
produced may be conveyed to fuses placed at considerable distance from the
firing-machine. On the other hand, the line resistance to low-tension
electricity is so great as to render it desirable to make the distance between
the firing-machines and fuses as short as possible.
In the year 1851 the author devised a low-tension fuse. A considerable
number were made, and used with much success at the Abercarn Colliery,
South Wales. These fuses were fired by a Grove battery. In 1862 Born-
hardt, of Brunswick, successfully completed his air-tight, high-tension fric-
tional-machine; and some years later Brain, of St. Annals, Cinderford,
arranged a frictional-machine. Siemens has also invented a dynamo-
A
P
صد
D
D
K
C
ரால்
a
Fig. 118.
A
K
TALEZAMIN
R
T
Fig. 119.
H
electric firing-machine.
At the Mechernich mines, Rhenish Prussia, a
galvanic battery in combination with a Ruhmkorff's coil were employed
for igniting the fuses; but both were soon abandoned on account of diffi-
culties experienced in the use of the apparatus. As the frictional-machine is
mostly employed for firing purposes in the mines of Europe and America,
and with a little care may be readily kept in a working condition, it will be
described, together with the leading wires or firing cables, connecting wires,
and fuses.
Firing Machine.-Bornhardt's frictional, air-tight machine is shown in
Figs. 118, 119. Fig. 120 gives the outside view with the handle in position
for charging the machine. Fig. 119 is a section of the machine showing
the internal arrangements, and Fig. 118 is a front view of it with
the door open, and the chains attached ready for testing its efficiency.
The machine inside consists of a thin ebonite wheel, about 10 inches
M M 2

534
[BOOK III.
PRACTICAL MINING.
diameter, which can be rapidly rotated by turning the handle shown in
position in Fig. 120. The top part of the ebonite disc is in contact with the
rubber R, Fig. 119, formed of cats-skin, carried by the arm H, and it is by
the friction of this skin upon the surface of the disc that the electricity is
generated. T shows an ebonite ring, of which there are two, placed
opposite one another, and furnished on the inside with metal points being
connected with the Leyden jar L, in which the electricity is stored after
having been collected from the ebonite wheel by the points in the rings T.
C D, Figs. 118, 121, are metal rings projecting through the front of the
machine, and it is to these rings that the ends of the wires forming the
circuit are to be attached when everything is prepared for firing. K,
Fig. 119, is the firing knob by which the electric discharge is made. This
knob being quickly pressed causes the arm G to be thrown into the
position shown by the dotted lines, thereby making contact with the con-
Fig. 120.
SYSTEM
BORNHARDT
denser, complet-
ing the circuit,
and allowing the
charge of electri-
city stored in the
jar to pass along
the wires, and in
its passage firing
the prepared shot-
holes simultane-
ously. In using
this machine, a test
and firing opera-
tion is necessary.
Test operation:
Immediately
in-
side the door of the
machine to the left
hand (Fig. 120) are
a series of brass-
headed nails. At
The hook of the
the top and at the bottom of these nails hang brass chains.
upper chain must be attached to D, Figs. 118, 119, and that of the lower chain.
to the bottom eye C. The handle of the machine must now be turned briskly
ten or twelve times, the knob K, Figs. 118, 119, pressed quickly inwards,
when, if the Leyden jar within the box has been fully charged, it will be in-
stantly discharged, the electric fluid appearing as a vivid spark leaping the
whole number of nail-heads. These nails are known as the "spark scale."
If, however, the electric spark should fail to leap, or to fill up, as it were,
the spark scale, the handle must now be turned a greater number of times,
not exceeding thirty. If the second trial should fail to obtain a spark of
sufficient strength to leap the entire scale, it is a proof that the wheel within
the box has become damp, and that it must be dried, either by keeping the box
within a warm room a sufficient time for that purpose, or otherwise by taking
FIRING CABLES AND CONDUCTING WIRES.
CHAP. II.]
535
off the cover of the box in such room, then drying and wiping the wheel with
a dry, warm silk handkerchief in front of a slow fire. Supposing, however,
that a strong spark is produced by the testing operation, the chains must
be thrown off; and when the fuses are connected together, and the men
removed to a place of safety, the leading or positive wire must be attached
to the ring D, and the return wire to the bottom ring, so as to form the
electric circuit. If now the handle be turned the requisite number of
times to produce the full spark, and the knob sharply pressed inwards, a
simultaneous ignition of the fuses will occur. To use this machine satis-
factorily, it should be sent underground for the purpose of effecting the
firing operation, and immediately returned to a warm, dry place. It is
essential that the inside of the apparatus (viz. the ebonite wheel and cat-skin
rubber) must be kept dry.
Firing Cables and Conducting Wires.-To insure complete transmission
of high tension electricity from the firing-machine to the electric fuses it is
necessary to employ conducting wires which are well insulated. When the
A
B
C
D
E
F
G
Fig. 121.
α
A
B
с
d
ď
f
e
h
C
leading wires are subject to rough usage, it is advantageous to form these
wires into a cable, protected on the outside with a covering of tarred hemp,
or, still better, with a sheathing of iron wire A (Fig. 121). A cable, B,
useful in situations where it will not be subjected to any rough usage,
consists of two cores or
strands, each composed of
three tinned copper wires,
insulated from each other
by two coverings of gutta-
percha, or india-rubber and
tape, stranded together, and
again insulated with gutta-
percha, or india-rubber and
tape; and lastly covered on
the outside with tarred hemp
to a diameter of five-eighths
of an inch. This cable may be conveniently hung to the roof or sides
of a level or shaft, or on poles in open workings. In use it is only
necessary to bare the ends of the copper wires in each of the cores, and
to connect; viz. two ends, one to the positive, the other to the negative
pole of the firing-machine; and at the opposite end of the cable and
conducting wire, to attach one end to the connecting wire of the first, the
other to the last connecting wire of the electric fuses. In this way the
electric circuit is formed. Fig. 121, A to E, show in section full-size firing
cables of various dimensions, sheathed with wire or guttapercha; F and G
guttapercha-covered copper wire, which under certain circumstances
Fig. 122.
D
536
[BOOK III.
PRACTICAL MINING.
may be used for conveying the electric spark; while Fig. 122, D, shows
a cable insulated with tape g and guttapercha h. To splice an insulated
cable it is only necessary to bare the copper wires for a short distance, to
B
scrape them bright, to twist them together,
Fig. 122, B, then to insulate the joint with
guttapercha, keeping the latter in position
by a piece of india-rubber tubing fastened to
the cable by wax thread or a piece of fine
cord, Fig. 122, C.
Connecting Wires.-These are short pieces of
copper wire, shown in section, Fig. 121, G, for
connecting the fuses together when the latter
are placed in the shot-holes. When the holes.
are near to each other, and the fuse wires toler-
ably long, the end wire of one fuse may be
directly twisted to the end wire of another, one
connecting joint being sufficient; but when
the fuses are some distance apart special
pieces of conecting wires will be required,
and two joints between each fuse will be
necessary. Fig. 124 shows the wires con-
necting the fuses lodged in the shot-holes,
and Fig. 122, A, the manner in which the
wires are twisted together. The ends of the
twisted wire should lie on the leading part of
the wire. Connecting wires should be kept
from touching the rock, as well as from
coming in contact with one another. In firing
shot-holes placed under water the connecting wires should also be insulated.
Electric Fuses.-An electric fuse consists of a long percussion cap
WITH
A
Fig. 123.
B
Fig. 124.
FIMBAULT
inclosing a fulmi-
nating and prim-
ing substance,
also an insulated
wire for conduct-
ing the electric
fluid. 'Two kinds
of fuses are made,
which are known
as "quantity" and
"tension" fuses.
The former are
fired by means of a battery, the latter by the application of a frictional-machine.
The priming or firing composition is placed within a cap, Fig. 123, into
which composition the electric wires are imbedded slightly apart from each
other. The ignition of the fuse is accomplished in the following manner :
The electric spark passes down one wire, leaps from the point of this wire,
firing the composition, to the point of the other wire, and passes up the
second wire. Fig. 123, A, shows an electric fuse inserted in a dynamite
CHAP. II.]
ECONOMY OF BORING-MACHINES.
537
primer. B, B, cartridges of dynamite laid on a shot-hole ready for electrical
firing by the machine.
Firing Operation.-Conducting wires or cables are usually fixed in a
level or shaft. As a level or shaft is advanced or sunk, the cables are
periodically lengthened, or shifted forward. Between the ends of the cables
and forebreast, of a level or bottom of a shaft, two pieces of insulated wire
a few yards long are roughly hung. One wire is attached to the first wire
of the first fuse, the other to the last wire of the last fuse, the intermediate
fuses being connected together with short lengths of wire, as already
described. The fuses and cable wires being connected together in single
circuit-that is, in a line or circle without crossing-the wires at the opposite
ends of the cables are attached to the positive and negative hooks of the
machine; viz. at C and D, Figs. 118, 119. The handle of the machine is
now turned a sufficient number of times to charge the jar, the knob K
is then quickly pressed, and the shot-holes, Fig. 124, at the same instant
are fired.
Economic Results.-At Ballacorkish, in the Isle of Man, both ordinary
and electric fuses have been used, one against the other. In driving the
60-fathom level, the economic value of each kind of fuse has been ascer-
tained. The following are the approximate results-
Number of holes in forebreast
Weight of dynamite per lineal fathom
Time charging and blasting
do. clearing gases
Saving per lineal fathom of ground
Safety Fuse, con-
secutive blasting.
Electric Fuse, simul-
taneous blasting.
18-22
25 lbs.
•
20-24
32 lbs.
30 min.
45.
20 min.
30",
205.
Mr. Joseph Ball, a practical miner, states: "With safety-fuse the men
have often to fire the centre-cut holes two or three times over, with electric
fuses only once. The harder the ground, the greater is the saving conse-
quent on the use of electric fuses. With safety-fuse the whole number of
holes can only be fired in three operations; with electric fuses two opera-
tions are sufficient." Others who have had a lengthy experience in electric
blasting, enumerate its advantages over ordinary fuse blasting thus—(1)
"It economises capital, time, and explosive material; (2) It is more certain;
(3) It is more effective, obstacles are overcome which cannot be removed
by the ordinary system of blasting; (4) It is safer, inasmuch as absolute
protection to life is secured."
At the Pribram mines, Bohemia, where rock-boring machines are
extensively employed in hard, tough, vughy, and jointy rocks, a compara-
tive trial was made-viz. in two shafts, two winzes, and four levels-for the
purpose of ascertaining the relative saving which could be effected in the
price per fathom, the wages paid per fathom, and the time requisite for
driving a fathom of ground by using (1) powder and safety-fuse, (2) dyna-
mite and electric fuses, and (3) dynamite and safety-fuse.
The results are given in the following table-
·
Saving per Saving per Saving per
cent. in
price per
fm, of
ground.
cent, in
cost of
wages
per fm. of
ground.
28
cent. in
time
per fm. of
ground.
Saving effected by using dynamite and electric fuses over that consequent
on the use of ordinary blasting powder and safety-fuse
Saving effected by using dynamite and safety-fuse over that consequent on
the use of ordinary blasting powder and safety-fuse
•
23
33
9
II
15
Absolute saving consequent on the use of electric fuses as compared with
the use of safety-fuse
14
17 .. 18
538
[BOOK III.
PRACTICAL MINING.
The essential points to be observed in electric blasting operations are, to
have a reliable fuse, a machine capable of giving a strong electric spark,
good conducting cables and insulated connecting wires, so as to ensure the
passage of the spark to the fuses included within the electric circuit.
Driving Levels and Sinking Shafts.-The success attendant on driving
levels and sinking shafts by means of machinery is only partly dependent
on the boring-machines. These machines now constitute but one of a
series of highly important inventions. Had it not been for the construction
of efficient air compressors, suitable machine carriages, properly jointed air
pipes, the discovery of strong explosives, the development of a new system
of arranging the shot-holes, the application of quick charging and blasting
these holes, together with thorough organization of the work, boring-machines,
however good in themselves, would have afforded unsatisfactory results. If
a careful inquiry be made as to the rate of boring attainable by individual,
but different machines, in one and the same rock, it will be found that, hole
for hole, one machine will probably be nearly as effective as the other; that
is, if the diameter of the cylinder, velocity of the piston, and width of the
tool be fairly equal. A speed of twenty fathoms per month, in a level with
four boring-machines, is no greater in the boring result than one of ten
fathoms per month accomplished by means of two machines. The work per
borer may be regarded as equal, although the speed of the advance in the
former case is doubled.
Although it will be desirable to adduce examples of quick and average
results attained, both in driving levels and sinking shafts, yet it must be
observed that no definite idea can be formed of the value of the circum-
stances which enabled the speed of one operation to be rendered sensibly
greater than that of another. The relative hardness, position, and character
of the rocks must be known; the conditions which aided or retarded the
work, correctly understood; the nature of the manual and mechanical power
which had been employed must be ascertained; these, and perhaps other
important details, may have to be adjusted one with another so as to
arrive at any just conclusions on the subject.
Organization and Conduct of the Work.-In driving levels or sinking
shafts with the aid of rock-boring machinery it is necessary to conduct the
operation in some special manner.
The appliances necessary at the forebreast of a level will in a measure
depend upon the number of machines to run together. If only one machine,
a simple vertical or horizontal bar will suffice; if two machines, two vertical
bars braced together at the bottom, or a vertical bar carrying two horizontal
bars. For running four or six machines together, heavy carriages will be
desirable. The driving of a heading may be classed under—
High tunnel speed, requiring from 40 to 50 hands.
High level speed,
Moderate level speed,
12 to 24
6 to 9
At St. Gothard (Airolo), where high tunnel speed was a necessity, and
sixteen or eighteen men employed together at the forebreast, the appliances
consisted of—
A carriage, weighing several tons, carrying six boring-machines.
CHAP. II.]
ORGANIZATION OF ROCK BORING.
539
A cylindrical reservoir, set to the rear of the boring-machine carriage,
for delivering water to the holes.
A waggon placed to the rear of the water reservoir, for holding and
running the tools to and from the forebreast.
Fig. 125 shows this arrangement in plan. The depth of cut is indicated
by dotted lines in advance of
the heading; the position of
the holes by angle - dotted
lines; and that of the work-
men by the small crosses. Thus
there is one man to each boring
Fig. 125.
X
tool, three men to the machines, one man in attendance on the air and water
supply, one man at the tool waggon, and one foreman stationed at the coiled
portion of the air pipe.
In Belgium, where Dubois and François have arranged various sets of
apparatus for driving ordinary mine levels at a high speed, the driving plant,
handled by four or five men per shift, consists of-
A carriage on which is mounted three or four boring-machines.
A cylindrical reservoir, to the rear of the carriage for supplying the holes
with water.
An electric cable.
Where the drilling appliances are arranged to suit the conditions incident
to the waggon and drawing ways, and to be handled by two or three men
per shift, the plant may include-
A small wooden trolley and stand, on which two machines are mounted.
A small pipe for conveying water to the holes.
An electric firing cable.
When rock-boring machines were first introduced the miner insisted on
employing them as mere substitutes for the borer and the mallet, and upon
placing the holes so as to “take advantage" of the ground. The result,
however, proved unsatisfactory. Not only was the time required to get a
position for the machine, to fix, and to remove it, excessive, but the work
accomplished was not in proportion to the cost. The engineers of the Mont
Cenis Tunnel were the first to recognise the fact that, if power machines
were to be employed for drilling shot-holes, the hand method of working the
ground must be discarded. A given number-ten machines—were there-
upon mounted on a carriage in such a manner that each could perforate a
given area of the face. The natural rupturing lines of the rock were disre-
garded, deep shot-holes were drilled, charged, and blasted, and in this way
a definite length of ground was removed. In France and Belgium this
length of ground is known as an "avance," in some parts of England and
America as a “cut" or "spell," while in shafts it is properly designated a
"sink." The divisions into which the entire operation of a "cut" or "sink"
is apportioned are as follows-
1 Circular cut system.
(a) Boring shot-holes 2 Square-cut
3 Radial-cut
(b) Charging and blasting the holes.
(c) Removing the stuff.
""
""
540
[BOOK III.
PRACTICAL MINING.
(a) Boring Shot-holes.-Two distinct systems of arranging the holes for
blasting purposes are in use-viz.:
1. The Circular Cut, which includes centre or rupturing holes, surrounded
by shot-holes more or less concentric with the rupturing holes, and angled,
so as to allow the explosive to remove, first, a centre core; second, the rock
encircling this core. Figs. 126, 127, and 129.
2. The Square Cut, in which the shot-holes are mostly parallel to the
sides of a level or shaft, the holes being angled so as to admit of the removal,
first, of a wedge; second, of the rock on each side of this wedge. (Fig. 135.)
1. Circular-Cut System.-The circular-cut system, devised in driving the
Mont Cenis Tunnel, is observed mostly on the Continent, and particularly
in the Seraing Collieries, Belgium.
In some cases a large centre "crushing" hole, from three to four inches.
diameter, is formed. (Figs. 126, 131.) Around this centre hole, within a circle
ten or twelve inches diameter, ordinary shot-holes are drilled. These circle
"
60 HOLES.
О
O
O
O
C
O
O
O
O
O
O
ооо
O
ооо
O
O
O
O
O
O
O
O
O
"/
9
8
holes are intended to
be fired together, so as
to crush up or break
out the centre. Outside
and around the centre
holes other holes are
drilled. Subsequently
the rock is removed by
blasting from the centre
outwards.
Mont Cenis. Fig. 126.
-The dimensions of
the Mont Cenis head-
ing, driven by means
of ten boring-machines,
were, height, 8 feet,
width, 9 feet 10 inches,
giving an area of 831
9" 10-
--3·3
Fig. 126.
square feet. The shot-
holes were placed as
shown in Fig. 126, and
included a centre, and eight concentric holes clustered together. Outside
of these holes, and inclosed within the first circular line, were other
twelve holes. Between the first and second circle, an additional fifteen
holes were bored; and finally, between the second circle and the walls of
the heading, twenty-four other holes, making altogether sixty shot-holes.
These holes varied in depth from 30 to 48 inches, and at bottom were 18
inch, and at top 1 inch diameter. The rock perforated consisted of mica-
schist, quartzite, crystalline, and Clay-Slate.
St. Gothard Tunnel.-The total length of this tunnel is 48,950 feet.
Two headings were driven; the Goeschenen forebreast, Fig. 127, was
usually perforated with 26 holes, 3 feet deep, the Airolo, Fig. 128, with
25 holes varying from 3 to 6 feet deep. The diameter of the shot-holes
CHAP. II.] DUBOIS AND FRANÇOIS'S BORING-MACHINES.
541
at top was 1 inch, at bottom 1 inch. In the Goeschenen forebreast were
three centre, then 8 second-cut holes, and lastly 14 side and corner holes.
At the Airolo end, five centre rupturing holes were placed slightly below the
centre of the heading. Over these were three equidistant holes, and within
the second rupturing circle, seven additional holes. Outside of this circle,
1
-------0--------
·O------
-O--
26 HOLES.
Fig. 127.
25 HOLES.
Fig. 128.
and at the top of the heading, were three corner right-hand and three corner
left-hand holes, at each bottom corner there was one hole. The rock per-
forated included Granite, mica, and other schists.
Anzin.-At the Anzin Collieries, France, boring-machines are exten-
sively employed. In a level, Fig. 129,
7 feet 10 inches wide at the bottom,
and 7 feet high, driven in stratified
schist and Sandstone, two centre rup-
turing holes were bored. These centre
holes were surrounded by 6 other holes
within a second circle. Between this
circle and the perimeter of the level,
10 additional holes were drilled.
I
Dia-
7:25/8″
19 HOLES
O
O
O
-4-11/2
O
-7.101/20
Fig. 129.
3
meter of holes at top, 1 inch, at bottom,
1 inch, depth of holes, 5 to 6 feet.
Dubois and François Levels.-Figs.
128 and 129 represent number and
direction of holes in plan and front
elevation in a level in Belgium, driven
by means of Dubois and François's bor-
ing-machines, the rock being mode-
rately hard, and the beds and holes parallel to each other. In the centre of
the heading is a large hole 4 inches diameter and 6 feet deep. This hole is
slightly angled from the axial line of the level. B, Fig. 131, is a hole 12
inches, and a second side hole 7 inches, from the middle of the centre
hole, each hole being 6 feet deep, and bored so as to be parallel to each
542
[BOOK III.
PRACTICAL MINING.
other. C and D are holes placed respectively 4 and 6 inches from the middle
of the centre hole, each 6 feet deep, angled so as to diverge slightly from the
centre hole. E F G H are a series of short holes, each about 3 feet deep,
angled as shown. Around the 10 centre holes are 22 additional holes. In
blasting by electricity the holes B C D G are first fired, then the shorter
holes. If safety-fuse is used, the firing commences with the hole B.
·6'6".
Fig. 130.
t
H
Fig. 131.
Figs. 132 and 133 show number and position of holes in a face of hard
rock 7 feet wide by 6 feet high, as arranged by Dubois and François. The
holes, A B C D, four in number, angled towards the axis of the level, are
bored within a circle 12 inches diameter. The second circle, placed about a
foot outside of the first circle, contains 6 holes almost in line with the axis
of the level. The third circle, distant a foot or thereabouts from the second
-6.6
N
E OA BO
*
Fig. 132.
Fig. 133.
circle, has 7 holes, each angled slightly from the axis of the level, while the
last or outer circle includes 16 holes, strongly angled towards the roof, the
sides, and bottom of the level. Altogether, in a face of rock containing 45
square feet, 33 holes are bored, each about 4 feet deep.
In a level recently driven at Carn Brea, 4 converging holes were drilled
around the axis of the level, then other 12 outside holes, making a total of
CHAP. II.]
SQUARE-CUT SYSTEM OF BORING.
543
16 holes in a forebreast 7' x 7', giving an area of 49 square feet. The average
depth of these holes was 42 inches; time of drilling 16 to 18 holes with four
machines, from four to five hours, or about one hole per machine per hour,
equal to a shift rate of 7 of a lineal inch per minute. In this rate is
included the time requisite for the introduction and withdrawal of the boring-
machine, carriage, angling the machines, and changing the tools. At
Maesteg, the heading in grit rock, 8 x 8, giving an area of 64 square feet, was
perforated with 16 or 18 holes, 3 to 4 feet deep, in about four hours. The
holes were commenced with bits 2ğ inches, and finished with bits 1 wide.
In the hard rock five bits were ordinarily required, in the soft rock three
sufficed to complete the hole. Careful judgment was exercised in drilling
the holes at the angle most effective for the ground to be blasted. The top
holes were generally set to rake upwards, the lower holes downwards. In
this case the boring result per machine was 48 inches per hour, making a
shift rate of of an inch per minute.
8
10
The method of sinking by the "circular-cut system" was introduced by
Darlington at the Minera mines, North
Wales, and at the Ballacorkish mines, in
the Isle of Man. The engine-shaft at the
latter mine is 10 feet diameter. A centre
or rupturing hole was dispensed with. Four
holes, each about 3 feet deep, were bored
so as to converge sharply towards the
centre. Around these, the centre cut holes,
two sets, including 20 holes, each 4 feet
deep, were bored. When necessary the
4 centre holes, Fig. 134, were from 1 to
2 inches diameter, the other or outside
holes, 11 inch diameter. At Ballacorkish
the four centre holes were first electrically
I
Fig. 134.
fired, then the holes in the second circle, and lastly the whole of the outside
holes.
Square-Cut System.-The "square cut" system was first developed at the
Hoosac Tunnel in America, about the year 1866, and perfected in driving
the Musconetcong Tunnel, six or seven years later. Mr. Drinker, in his
able work on "Tunnelling," thus describes this system: "At first 31-inch and
then 4-inch drills were tried, but finally the 5-inch was decided on, as by far
the best size in the hard rock encountered. The drills were mounted in
the heading on two carriages, one on each side of the centre line. These
carriages were simply frameworks of oak, running on rails carried up to the
face of the heading. Fig. 133 shows a plan of the fore part of one of these
carriages, there being two in the heading, one on each side. After a blast,
all hands were at once engaged in shovelling and filling the broken rock into
the middle of the tunnel, between the machine rails, so as to clear the latter.
As soon as the way was clear, the carriages were at once run up to the face
and drilling recommenced, and the broken rock subsequently removed in
waggons running on the centre way.
"The heading being 26 feet wide, there was room enough to accommo-
544
[BOOK III.
PRACTICAL MINING.
date the three roads, and by proper switching there was rarely any deten-
tion from want of waggons. The method of blasting by cuts is based on the
extraordinary force developed by a comparatively small bulk of explosive
matter.
"It consists in first blasting out an entering wedge or core about 10 feet
deep at the centre, and subsequently squaring up the sides by several
rounds; to do this twelve holes are drilled by the six machines, three sets
on a side, the holes placed as shown in Fig. 136, and marked c, A, being the
5
6
5
3
floor of the heading. These twelve holes
are drilled two and two, six on a side,
with from 1 to 2 inch bits, the two sets.
being started about 9 feet apart, and at
such an angle as to meet or cross at the
bottom, the largest bits being put in
first.
"They are then charged with about
25 lbs. No. 1 and 50 lbs. No. 2 dyna-
10
1.03
8C
Co 10 20
02
03
02
0/
8c
co 10
30
20
02 ol
oc
A
c8 lo
20
30
Fig. 135.
Fig. 136.
mite, and fired simultaneously by electricity. No. 1 dynamite is only used
for cuts, inasmuch as in them a quick, strong explosive, comprised in
a small bulk at the bottom of the holes, where the greatest resistance will
be found, is required; while No. 2 dynamite added serves in filling the
holes, so starting the sides of the cut as the apex is moved. The cut being
out, a second round of holes is started for the first squaring up, as shown by
the Nos. 1, I, I, I.
"In these, and in the subsequent rounds 2, 2, 2, 2 and 3, 3, 3, 3, the
resistance is equally distributed along the whole length of the holes,
and is also not so great as in the cut; therefore No. 2 dynamite is used, as
in it the nitro-glycerine being mixed with a larger proportion of absorbent
matter, the force is thereby distributed over a greater space.
"In the first and second squaring-up rounds from 50 to 60 lbs. of No. 2
dynamite are charged, and in the third from 80 to 90 lbs., the holes getting
stronger as the arch falls at the side. There are also generally one or two
additional roof holes in the third round that are not shown in the figure,
their position being variable according to the lay of the rock. The top holes
in the first round are also designed to bring down any roof not shaken by
the cut, and are therefore given a strong angle towards the centre, and
always drilled from 12 to 14 feet deep.
"The horizontal projection of the above holes is shown in Fig. 135, 3 being
the centre cut holes, 4, 5, and 6 the squaring up rounds.
"As to their relative depths, the holes of the first squaring rounds are
CHAP. II.]
BORING AT BALLACORKISH.
545
always drilled a foot or more deeper than the cut holes, and when blasted
they generally bring out a foot additional of shaken rock at the apex of the
cut. The following table approximately shows the number and depth of
holes required, and the dynamite used for a lineal advance of 10 feet of
heading work :-
No.
of
holes.
Depth of
holes
in feet.
Cut, or centre wedge
12
•
101
Ist square up
2nd do.
3rd do.
888
6
12
I 2
12
Roof holes
2
•
Total depth
Dynamite used.
No. I.
No. 2.
い
​36
of holes
in feet.
126
25
•
50
96
•
55
96
55
72
{18}
18
85
408
25
245
Total
270
"Now allowing the cut holes to be 10 feet deep, the cut will generally
blast about 9 full linear feet. Assuming the average cross section-width
26 feet, height 8 feet—to be about 175 square feet for a lineal advance of 10
feet, 65 cubic yards of rock would be broken, which would give an average
of say four-tenths of No. 1 and four pounds of No. 2 dynamite consumed to
the cubic yard of rock, and a little over 6 feet of hole drilled per cubic yard
broken." As to the division of time, it took one shift to drill and blast the
cut, and one shift to each of the three rounds, making a period of twenty-
four hours. The work was effected with a force of twelve men per shift, or
forty-eight to the pare; viz. one driller and one helper to each machine;
together four men, six trammers, one assistant carrying tools, and one
foreman. The square-cut system has been adopted in driving headings at
the Minera mines, North Wales, and at Ballacorkish, in the Isle of Man.
At the former mine, in cherty, drusy Limestone 200 yards below the surface,
a cross-cut 6 feet wide by 62 feet high was driven by means of two machines
mounted on a stand. One machine was at work while the other was being
arranged for boring another hole. The shot-hole at top was 1 inch, and at
bottom 1 inch diameter. Owing to the "short jointy" nature of the rock,
deep holes could not be carried without incurring a heavy cost for dynamite
-a cost disproportionate to the gain acquired in speed. The following
figures give the number of holes, total depth, and weight of dynamite used
for a cut of 2 feet 9 inches :—
I
Cut
First square up
Second do.
Roof-holes
Total depth Dynamite
of holes. consumed.
No. of
holes.
Av. depth
of holes.
IO
3
30
8
2
22
8
2
22
12-13 lbs.
2
3
6
28
80
8∞∞
At Ballacorkish the heading, 6 feet wide by 7 feet high, was driven
partly in the country and partly in the lode.
The country rock was composed of short-jointed Clay-Slate, the lode of
quartz, and various other minerals of different degrees of hardness, frequently
enclosing vughs, or openings. The end was perforated with seventeen or
eighteen holes of an average depth of 44 inches, and a bottom diameter of
1 inch.
The time required for drilling the holes with two machines,
546
[BOOK III.
PRACTICAL MINING.
including fixing and removing the stand, shifting the machines, and chang-
ing the tools, was from seven to eight hours. Number of holes per machine,
per hour, or a shift speed of
of an inch per minute.
26 TO 28 HOLES
10
·6′·6"-.
�<--3'·0" -->
ΟΙ
10
I
Minera Mines.-Fig. 137 re-
presents the face of a cross-cut in
this mine driven with two Dar-
lington machines. Height of
cross-cut, 6 feet; width, 6 feet;
area of face 40 square feet; num-
ber of holes in heading, 26 to 28;
average depth of holes, 34 inches;
diameter of holes at bottom, 1
inch; area of face to one machine,
20 square feet.
Cut
First square up
Second do.
•
Io holes each, 3 ft. deep.
2 2
8
""
8
26
Roof-holes.
2
3
Total 28
•
AAKUPKO
"
Fig. 137.
Cut electrically blasted as follows: (1) Cut or centre, 10 holes; (2) First
B
·
C
B
A
||
11
"
||
11
A
10'-6"
A UC
A
A
A
A
C
Fig. 138.
C
14
ос
B
11
square up, 8 holes; (3) Second
square up and roof-holes, 10.
Mixed-Cut System.—This sys-
tem is in use at Ballacorkish, in
the Isle of Man. For particulars
and illustration, see page 554,
Fig. 142.
In sinking pits Dubois and
François have resorted to a sys-
tem of shot-holes of large and
small diameters, and combined
the square with the circular-cut
system. Fig. 138 represents a
plan of a shaft, together with the
position of the various holes.
3
The holes, each 4 feet deep,
are angled, as shown in the ver-
tical section. The four central
holes, A A A A, as well as the
corner holes, B B B B, are 1 inch
diameter, while the other holes
are 11 inch diameter at the bot-
tom. The number of holes in the
bottom of a shaft 10 feet long
by 7 feet wide are eight 1 inch
3
diameter and twenty-eight 1 diameter. The holes are electrically blasted,
CHAP. II.]
RADIAL-CUT SYSTEM OF BORING.
547
the first volley being the four centre holes, then the six outside holes, and
lastly the perimeter holes.
Radial-Cut System.-Mr. W. Blanch Brain, of St. Annals, Cinderford,
when driving a level at the Drybrook mines, employed a horizontal stretcher
bar, and fixed it in such a position with the height of the level and the
length of the machine as to perforate the face, by simply radiating the
machine on the bar for drilling the shot-holes on a vertical line at the
requisite angles, and shifting the machine on the bar to repeat the boring
operation. This Mr. Brain designated the "radial system."
CABLE
Fig. 139 shows the sectional form of the Drybrook level, the disposition of
the holes, and the line of the electric cable
for obtaining the cut. Rock-dolomite-
width of level, 6 feet; height, 63 feet; area
of heading, 40 square feet; number of holes
in heading, 34; depth of holes, 3 feet to
4 feet 3 inches; diameter of holes at bottom,
1 inch. The rock removed by the first
blast included the portion between the bot-
tom and upper cable line; the second blast,
that between the upper cable line and the
roof.
CABLE
<9/7/›
Fig. 139.
Observations.-The form and character
of rock-boring machines, together with
the method resorted to for mounting them, render it necessary that the
circular, square cut, or a combination of these two systems, should be
employed for the purpose of effecting the removal of the ground, both in
levels and shafts. No diagram of the holes, which may seem to be necessary
for obtaining a cut or sink, can be advantageously followed. A clever miner
will take advantage, it may be a limited one, of faces, joints, and lie of the
ground, so as to minimise the number of the shot-holes and weight of
explosive necessary. He will bore the shot-holes as deep as possible, or, in
other words, as deep as the explosive is likely to produce a satisfactory
result, so as to quicken speed and lessen the dead cost; he will seek to get
out his cut, or wedge, in a part of the face where the resistance is least; and
acquaint himself fully with the mechanical conditions of the machines, and
the stands to which they may be attached. The general tendency of recent
practice is to bring into use larger machines for boring; to increase the
diameter of a part, if not of the whole of the shot-holes; to lessen the number
of holes in a given area of rock, and to employ a greater proportion of
dynamite per hole.
At Musconetcong the centre wedge was removed by a series of double
shot-holes; that is, two holes were bored side by side and heavily charged
with No. I dynamite, while the sides, or square up cuts, were removed by
the use of No. 2 dynamite. The Mont Cenis engineers bored an axial or
central hole, and clustered around it other shot-holes, converging towards
the line of the centre hole. The centre hole was not charged with powder,
but the outside ones were heavily so, and when fired broke out the centre of
the face, so that the surrounding rock presented the form of a cone. Dubois
N N
548
[BOOK III.
PRACTICAL MINING.
and François greatly extended the use of this method; but of late these
engineers, doubtless through their wider experience, have in some instances
modified their practice, and resorted to a mixed system of large and small
holes, placing the former on the line of the greatest resistance.
At Ballacorkish, where from the peculiar and variable character of the
ground the centre-cut holes, eight in number, were placed below the normal
axis of the level, while the cuts were made from roof to sole, rather than
from side to side of the level. In this case, as in almost every other where
ground is irregular in its character, the centre-cut is best made in a part of
the face where resistance to the rupturing strength of the explosive is least,
while the surrounding holes should be so placed as to help each other in
the blasting operation.
The rate of speed which may be obtained in boring is not to be measured
by one drill running against another; but it must include the time requisite
for fixing and shifting the machine, changing tools, and attending to other
details, some of which will be incident to one machine and not exist in con-
nection with another. This may be distinguished as the "shift speed."
Further, the length and constructive character of a machine will affect
the angling range, and entail consequences of a pecuniary character. If the
angling range be low, that is, almost parallel to the side of the level, a
greater weight, or a stronger explosive, will be necessary for shifting the
ground than if the holes were more sharply inclined towards the face.
TABLE I.
APPROXIMATE SHIFT RATE OF BORING SHOT-HOLES IN VARIOUS ROCKS BY SUNDRY BORING-
MACHINES, INCLUDING IN THE SHIFT THE TIME REQUISITE FOR FIXING AND WITHDRAWING
BORING TACKLE, Shifting Boring-machineS, CHANGING TOOLS, AND DRILLING THE HOLES.
Name of
Place.
Name of
Machine.
Machine Cylinder
Diameter of Boring
in Inches.
Diameter of Shot-
hole at Bottom.
Shot-hole per
Minute.
Shift Rate of Boring
Rock.
Musconetcong
Minera
Maesteg
Portskewet
•
Cwmbran .
Dolcoath
Marihaye
St. Gothard
•
•
Laxey .
Ingersoll
Darlington
Beaumont
Geach
McKean.
Barrow
Inch.
•
52 434 4 2 32
I.20
AKU
1.00
Syenite.
Tough Limestone.
I'00
Pennant Sandstone.
3 1/
0.90
0.80
Pennant Sandstone.
Pennant Sandstone.
0.80
circol4-ka
c.80
0.80
0.80
Hard silicious tin lode,
Sandstone and shale,
Granite and gneiss.
Hard Killas and spar.
Dubois François
Ferroux
Ingersoll
NOTE.-The comparatively high shift rate of boring obtained at Musconetcong was due partly to the
great power of the drills, and partly to the circumstance that the cut-holes were nine feet deep, giving a
larger proportion of time to the boring operation than is obtainable when ordinary three-feet cuts are
made. In the latter case, the tackle must be shifted three times to obtain an advance of nine feet,
whereas in the former case it was only shifted once.
Charging and Blasting.-Holes bored by machine drills cannot be
placed in accordance with the line of least resistance. To compensate in
some degree for this defect incident to machine work, the strength of the
charges should be varied according to the resistance which they will be
required to overcome. The holes for unkeying the face will require the
CHAP. II.]
AND
CHARGING AND BLASTING.
549
heaviest charge of explosive material, since the conditions for getting out the
cut or wedge are usually most unfavourable for the power of the explosive.
The quantity of explosive for each hole must vary greatly, since it will be
dependent on the nature of the rock and the resistance offered to the blast.
The proper charge can only be ascertained by experience. If holes are
fired singly more dynamite will be required than if fired simultaneously.
For taking out the wedge or centre-cut the strongest dynamite should be
used. For enlarging the face around the wedge or centre-cut No. 2 or 70
per cent. nitro-glycerine dynamite will often prove strong enough. In
Schist, and Sandstone rocks of a bedded character, good
results have been obtained by the use of cartridges of
compressed powder ignited at the bottom. (See elevation
and plan, Fig. 140.) At Ronchamp, in France, dynamite
and powder exploded together gave excellent results.
It was held that the powder prolonged, as it were, the
time of the explosion, and exerted its force on the rock
weakened by the quicker rending strength of the dynamite.
At Musconetcong the strongest dynamite, containing 75 to
77 per cent. of nitro-glycerine, was employed for unkeying
the face, the square-up or side cuts being subsequently
removed with dynamite of lesser strength.
O
Fig. 140.
At St. Gothard very deep holes were tried; but in many
instances it was found that "sockets" were left after the
holes were blasted. By giving the holes a greater diameter
this drawback was materially abated. As, however, the
consumption of dynamite was found to be large, it was
afterwards used surrounding a cylinder of clay. In this
way the weight of explosive was said to be sensibly lessened
without decreasing to a proportionate extent the measure of
the result. To obtain a maximum effect from the detonation
of dynamite it should be placed at the bottom of the shot-hole, and confined
by water, or otherwise gently tamped with about three inches of soft clay.
Many miners assert that tamping is unnecessary. The fact is, it is not so
essential a matter with quick-rending explosives as with black powder. In
the one case the liberation of the expansive gases is instantaneous, in the
other it is gradual; but with any explosive the complete confinement of the
gases must increase the effect. The filling up of any space around the
charge is also important. Experiments conducted in America for ascertain-
ing whether a small space between a ball and a charge at the bottom of a
mortar would have the effect of lessening the distance to which the ball
would be thrown, showed that with a quarter ounce of No. 2 dynamite, which
constituted each of the charges, the loss was very great.
Expt.
No. I
Ball raised from Bottom of
Charge in Mortar.
0.0 inch
0.05",
O.IO
2
3
""
4
0.20
"
6
0.40",
0.60
0.80
""
>>
Thrown.
Loss.
630 feet
579 "
51
80
550,
490",
140
440",
190
•
400",
230
350",
280
N N 2
550
[BOOK III.
PRACTICAL MINING.
If water be employed for tamping purposes, the detonators attached to
the fuse should be protected so that no water can enter between the fuse
and the detonator to interrupt the igniting operation. Even if the fulminate
should become damp this circumstance alone will materially lessen the
power of the fulminate, and, perchance, cause the dynamite to burn, losing
thereby its money value, as well as its disrupting effect. The order of firing
the shot-holes should be determined at the time of charging and tamping
them. Naturally such holes should be selected as will rupture and unkey
the rock to the desired depth, and which will also secure the most effective
results on firing the second set of shot-holes. When successive series of
holes are to be fired by means of safety-fuse, the length of the fuses may be
regulated, if necessary, so as to effect the discharge of certain holes earlier
than that of other holes. If also the ends of the fuses be brought together,
their ignition may be accomplished at one and the same time. This may
be effected by inclosing the ends in a small powder cartridge, and firing the
latter by a short piece of safety-fuse.
Ventilation.-Immediately after blasting a set of shot-holes any noxious
gases resulting from the explosion should be quickly removed.
To effect this object compressed air may be discharged from the air-pipe
close to the forebreast. The air for ventilating purposes need not be highly
compressed, the pressure of a single atmosphere will suffice. If air under a
pressure of three or four atmospheres be used, and steam employed for
compressing it, the cost of fuel will prove to be unnecessarily high. At
St. Gothard large exhaust-bells were erected for withdrawing the vitiated air
from the headings; but sixteen compressors in action were found to afford
sufficient air for aeration and for boring operations. At Cwmbran, South
Wales, a large fan, in connection with wooden trunks 12 inches wide and
30 inches high, was used to exhaust the air from the heading. At Port-
skewet the foul gases were withdrawn from the heading through zinc pipes
12 inches diameter. At Ballacorkish these gases were blown from the
60-fathom level forebreast, an air cock being left open for that purpose
previous to firing the shot-holes.
Removal of Stuff.-Before blasting it is desirable to lay down in front
of the face a piece of sheet-iron, so as to enable the men to shovel the stuff
more readily into the waggons. When a double railway is laid in the level
one waggon may always stand empty at or near the forebreast, while the
other is in course of filling; but where a single way is laid it is desirable
either to have a loop or shunt not far distant from the forebreast, so that the
loaded waggon may be quickly removed and replaced by an empty one. In
the sinking of the Ballacorkish and Minera shafts, the main drawing kibble
was invariably sent from the surface to the bottom. In the former instance
a wrought-iron pent-house was always directly over the heads of the men,
to protect them from the fall of a stone or other substance. A simple way
of quickly withdrawing the stuff from shafts, fitted to a given depth with a
skipway, is by means of an hydraulic or pneumatic winding engine. The
former might in many cases be driven by a small two-inch pressure pipe
attached to the upper part of the pump-work. For every 50 fathoms of
vertical height the pressure may be reckoned at 125 lbs. per square inch.

CHAP. II.] PNEUMATIC ENGINE FOR UNDERGROUND.
551
A water pressure of 700 or 800 lbs. per square inch may he satisfactorily
employed. If pneumatic engines are used the air should be worked
expansively, and the heat extracted from the air during its compression,
partly restored to it dur-
ing its expansion within
the cylinder, viz. by con-
tact with a finely-divided
spray of water delivered
as warm as it can be ob-
tained. A compact and
useful pneumatic engine
devised for underground
hauling purposes is
shown in Fig. 141. The
cylinders are 6 inches
diameter and 10 inches
stroke, drum 27 inches
diameter, geared 6 to 1.
With 40 lbs. of air the
engine will rapidly lift a
load of 1,500 lbs.
Time and Speed.-The
CHEST
FOUNDRY
No 12
M440))
HARE
Fig. 141.
time occupied in completing a cut of ground will in effect summarise the
speed of the various operations. In boring the shot-holes a specific portion
of time is required for-
(a) Introducing and fixing the boring-machine frame.
(b) Boring shot-holes
Angling and shifting the machines.
Changing boring tools.
Boring holes.
(c) Unfixing and withdrawing the boring-machine frame.
The time requisite for the introduction and withdrawal of the machine
frame (a and c) may be taken as a constant factor; that is, the time of the
operation incident to one and the same apparatus will not vary, whether the
apparatus may carry one or four boring-machines. In the matter, however,
of boring the shot-holes with one or four machines, the time will not vary in
inverse proportion to the number employed, but it will diminish in an
increasing proportion with an increase in the number of the machines.
One machine perforating an entire face (7 feet x 7 feet) giving 49 square
feet, must be shifted to the requisite parts of this face, admit the change of
tools necessary for running down the whole number of holes, and must
therefore be charged with the entire amount of time necessary for shifting
the machine and changing the tools.
Four machines employed on a face will divide it into quarter sections.
If twenty holes, each 3 feet deep, are necessary for the cut, it follows, one
machine will operate on an area of 12 feet, and run down five holes.
To bore twenty holes, 3 feet deep, one machine must be angled and
shifted at least twenty times. If three tools are required per hole, sixty
tools must be changed to bore the twenty holes.
552
[BOOK III.
PRACTICAL MINING.
The time incident to shifting or angling a machine so as to command a
fresh hole, and to changing the tools for boring the hole, cannot be fairly
reckoned at less than two minutes, consequently the time imposed on one
machine per cut of ground is—
Introduction and withdrawal of the machine, say
Shifting and angling machine (20 × 2)
Changing tools (3 X 20 X 2)
One machine
•
•
30 minutes.
40
120
•
190
""
Now if two machines be employed it is obvious that the time of shifting
and changing the tools, 160 minutes, will fall on two machines, or 160
minutes will be represented by 80 minutes.
Tabulated on one, two, and four machines, the result will be—
Introduction and withdrawal of machine frame.
Shifting and angling machine
One.
30 min.
No. of Machines.
Two.
30 min.
Four.
30 min.
Changing tools
40
120
20
""
""
""
60
Relative time necessary
•
•
190
IIO
10
30
70
Thus by the concurrent application of four machines to the face, the gain
in time in the boring operation over the use of one machine is about sixty-
three per cent. In other words, four boring-machines, to make three cuts of
ground, will only abstract from the boring period as much time as will be
required in the application of one machine to make one cut. A high boring
speed is therefore attainable by dividing and distributing the various opera-
tions of delay over two, four, or six machines, instead of imposing them on
one machine.
In the charging and blasting operations time can only be saved and
speed acquired by observing the following general rules :-
On the completion of the boring operation let the cartridges be prepared
so as to place them directly into the holes to be fired.
If the holes are to be electrically fired, let one or both of the wires be
of sufficient length to form one instead of two mechanical connections
between two fuses.
Fire a maximum number of shot-holes together, and dislodge the cut in
at least two firing operations.
As it may be assumed that the time required in each blasting round,
apart from the charging and firing process, viz. for the removal and return
of the workmen to their positions, and for exhausting the gases from the
face, will not be ordinarily less than ten minutes, it follows that if four
firings are made per cut, the aggregate time will be forty minutes; whereas
if it be two firings, the time will be reduced to twenty minutes.
In the removal of the stuff a similar necessity exists to do the work
quickly; that is, if a maximum speed of drivage is to be obtained. The
obvious rule for observance is to remove the stuff just a sufficient distance,
or in such a manner, as to get the machines to the forebreast in the shortest
time possible so as to commence a fresh cut. If the machine men have to
"waggon the stuff" to such a distance that they can only get rid of four tons
per hour, and other arrangements are practicable by which the forebreast
can be relieved to a threefold extent in the same time, then the stuff yielded
CHAP. II.]
EXECUTION OF WORK BY MACHINES.
553
by a 31-feet cut in a forebreast 7 feet x 7 feet would be roundly 16 tons,
while the gain in time would amount to 66 per cent.
Thus 16 tons at 4 tons per hour
16
""
12
""
Gain per cut
4 hours
It
"
23 = 66 per cent.
It is therefore evident that a high-speed result is consequent on running
several boring-machines together, executing each operation quickly, shorten-
ing the period of such delays as may bear on the actual boring, charging
and firing of the hole, and on instantly ridding the face of dislodged stuff, so
as to introduce the machines for a fresh attack.
The approximate length of time required (1st) to bore the shot-holes
with four machines, (2nd) to charge, blast, and remove the stuff, has been
tabulated by Messrs. Dubois and François as follows:
Character of Rock.
Soft schist
Hard schist
Ordinary gritstone
Hard gritstone
•
Hard gritstone and quartzite
Proportion of Time
employed in boring
the Shot-holes with
Four Machines.
0.30
0.35
0'40
0.50
0.65
Proportion of Time
employed in
blasting and removing
the Stuff.,
0.70
0.65
0.60
0.50
0'35
WORK EXECUTED.-The works executed in this country with the
Darlington rock-boring machines fall within the class of moderate level-
driving speed. In every case only two boring-machines have been
worked together, while the number of men employed per shift has fre-
quently been two, and never more than three, or six or nine men to the
"pare." In addition the men have usually had to tram the stuff to the
shafts, and in one or two instances to place it in the kibble. These opera-
tions are in a sense outside hindrances to the normal speed which should be
acquired in the use of such machines. At Ballacorkish, in the Isle of Man,
the engine-shaft, 10 feet diameter, was sunk by twelve men at the rate of
about 2 fathoms a week. The time occupied in the three distinct operations—
(1) Boring the shot-holes,
was as follows:
(2) Charging and blasting them,
(3) Removing the stuff—
184 hours or 20 per cent. of total time.
•
Boring shot-holes
Charging and blasting
Removing stuff
94
666
ΙΟ
70
"
944
100
""
The weight of dynamite consumed was 329 lbs., which removed 704 tons
of rock.
Dynamite consumed per lineal fathom of ground
""
>>
cubic yard of ground broken
ton of ground
•
•
232 lbs.
11%
""
>>
•
81%
52 inches.
46
""
Lineal 'feet of shot-holes made per cubic yard of rock
Average depth of holes per cut
Average depth sunk per cut
.
The men who conducted the work were taken direct from the tribute
pitches, and at the end of a 20-fathom contract were sinking at the rate of 2
fathoms a week, although an 8-inch pump 23 fathoms long had become very
heavy to handle, and the drawing appliances were altogether below the
capacity and speed requisite for a quick dispatch of the work. The rate of
554
[BOOK III.
PRACTICAL MINING.
speed at which the shaft was sunk was five-and-a-half times quicker than
could have been accomplished by hand labour alone. The hand price for
the shaft was £31 10s. per lineal fathom; the machine price £13, which
included the cost of coal for the compressor. On completing the engine-
shaft to the 60-fathom level, a plat was first cut by means of the boring-
machines; second, a long cross-cut driven to the lode; thirdly, a level 6′ 6″
wide by 7' 0" high extended partly on the lode and partly in the country for
a length of 150 fathoms.
Nature of Ground.—The ground through which the level was driven for
the length referred to consisted of tough, jointy Clay-Slate, occasionally
varied with quartz, forming two-thirds of the width of the end, then the lode
itself inclosing quartz, blende, lead, patches of slate, vughs, and joints.
The boring-machines employed were two in number-single acting,
with an effective pressure equal to a cylinder 2½ inches in diameter.
The number of blows per minute at an air pressure of from 50 to 55 lbs.
per inch was about 400. The length of stroke varied from 3 to 5 inches.
These machines were fixed on a frame, shown in Figs. 6, 7, and 8, one on each
of the horizontal arms. The machine on the upper as well as on the lower
arm drilled the holes in opposite quarters of the face; when this was done, the
arms were turned to the opposite side, and the full number of holes drilled to
complete the operation. The time required for boring the holes varied
according to the nature of the ground in the lode, since it happened that the
EM
*
6.6
Fig. 142.
drilling of the "lode holes" some-
times took double or treble the
time required to drill a similar
number in the Slate; not through
hardness of veinstone, but be-
cause of the prevalence of fissures
and "heads" diverting the nor-
mal path of the tool.
Holes.-The sectional dimen-
sions of the level were-width,
6 feet; height, 7 feet. From the
circumstance that it was neces-
sary to carry a portion of the lode
with the level, the holes were usu-
ally bored, as shown in Fig. 142
(1) To obtain the centre cut;
(2) To remove the country rock;
(3) To blast down the lode.
The relative position of these
holes is shown in Fig. 142. The
average diameter of the holes at the bottom was 14 inch; depth, 44 inches;
but holes 52 and 54 inches deep were frequently drilled and blasted.
Charging and Blasting. The charging and blasting of shot-holes involved
three separate operations-the holes I were first charged and blasted, then
the holes 2, and finally the holes 3. The three several lines, 1, 2, and 3,
on the face of the level (Fig. 142) show the circuit wires which connect the
electric fuses for each blast.
CHAP. II.]
DAILY RATE OF DRIVING.
555
The following statistics apply to a length of 79 fathoms 5 feet 8 inches
driven in the 60-fathom level by six men and three labourers, or nine men
in the "
pare," during a period of twenty-nine weeks, the nine men tram-
ming the stuff from the forebreast to the shaft :—
Number of machines employed together
"
holes bored
feet bored
Average depth of holes
•
Number of feet of hole bored to remove a cubic yard of rock
Number of bits blunted per running fathom
Weight of dynamite consumed
Average weight of dynamite per
hole
cubic yard.
""
""
per lineal fathom
ton of stuff broken
Number of cuts made
Number of tons of stuff removed
Average number of holes per cut
Length driven per cut
•
Average length driven per week
Maximum length
""
•
Time occupied in the various operations—
2
2194
8279
44 inches
10,3
28
1654 lbs.
7
10 ""
7
2010",
216",
O'94 ",
142
1754
16
40 inches
17 ft. 8 in.
28 feet
Boring the shot-holes.
•
1325
Charging and blasting
Removing the stuff
or 41% of total time.
442,, 131% ""
1055 ,, 321-
Putting in air-pipes and laying railway
Hindrances
180/1/20
203
51€/
6
610
3206
ΙΟΟ
Rate of Driving.-The rate of advance per day of twenty-four hours in
tunnel levels is found to vary from 7 to 12 feet, and in mine levels from 1 to
7 feet. The time occupied in boring the holes must naturally depend upon
the number of machines and men employed together, upon the power and
handling of the machines, upon the diameter of the holes, as well as upon
the nature of the rock.
TABLE II.
DAILY RATE OF DRIVING IN SUNDRY LEVELS BY MEANS OF ROCK-BORING MACHINES.
Name.
St. Gothard, Airolo
Musconetcong.
Sutro
Maesteg
Anzin
•
Anzin
Halkyn
Ballacorkish
Blanzy
Foxdale
Ditto
Marihaye
Portskewet
Cwmbran
Minera
•
Carn Brea Level
Ditto Shaft
Dolcoath Level
•
Machine.
Size of the
Level.
Diameter of Hole
at Bottom.
Total
No. of Men
employed.
Rate of Driving
per 24 Hours.
No. of Machines
employed.
Diameter of
Boring Cylinder.
Rock.
·
Inch
Feet.
Dubois & François
Ingersoll
8.6 × 8.2
26.0 x 8.0
X
I
Beaumont
·
Beaumont
Darlington
Ditto
Ditto
Barrow
8·0x8·0
8.0 x 8'0
7°0 × 6·6
7·6×7·6
7·6 × 5·6
7·6×6·0
---2-2-A
H
I
39
IO
6 3/31/1
48
ΙΟ
6
4
.∞
8-9
4
•
4
8-9
H
9
Dubois & François
Geach
6'0 x 6'0
8.0 x 8.0
HHHHH
I
9
3-4
4호
​I & 2
2
6
I
11-2
I
I
4
9
1-2
I
I
9
6-6.
I
66
17-8
2
McKean
100 × 7'0
Darlington
6.6 × 7.0
Beaumont
Ditto
8.6 x 8.6
15.0 × 8.6
Barrow
8.0 x 6.0
-
1++ Pro-K
29
7-9
2
Ditto
9
10 & 2 boys
12 & 2 boys
9
23/13-3
I & 2
28
4老​秀
​4
2
Ditto
1 & 2 3 & 4 Ditto
Inches.
3i+4
42323mm+~++*
M
1500-10010000
Mica and schist.
Syenite.
Pennant.
Sandstone.
Limestone and quartz.
Tough Slate and quartz.
Sandstone.
Quartz and spathose iron.
Hard bastard Granite.
Shale and grit.
Pennant Sandstone.
Limestone, quartz, &c.
Hard silicious tin lode.
do.
ditto.
ditto.
556
[BOOK III.
PRACTICAL MINING.
An uniform, clean-cutting, coarse, hard-grained rock may be bored quickly;
a fine-grained, tough rock will be drilled slowly; while a fissured, vughy rock
will frequently "fitcher" the tool, unless the machines have in themselves
an excess of power, and the bit be of a suitable form to maintain the line of
the hole.
The weight of dynamite per cubic yard of rock broken will be found
to vary from 1 to 4 lbs. The number of lineal feet of shot-hole for
the same measure of rock is from 4 to 16 feet. When the number of lineal
feet of shot-hole is great in proportion to the sectional area of the face, the
quantity of dynamite appears sensibly to decrease.
TABLE III.
STATEMENT OF APPROXIMATE WEIGHT OF DYNAMITE USED FOR THE EXTRACTION OF A
CUBIC YARD OF ROCK, AND AGGREGATE DEPTH OF HOLE BORed.
Name.
Machine employed.
Diameter of Shot-
hole at Bottom.
Average Depth
of Shot-hole.
Weight of Dyna-
mite per Cubic
Yard of Rock.
Average Length
of Shot-hole
per Cubic Yard of
Rock.
Rock.
Maesteg
Musconetcong
Portskewet
Cwmbran
Perka Pits
•
Carn Brea Level
Ditto Shaft
Roskear
•
Beaumont
Ingersoll
Geach
Ins. Inches.
42-48
120-130
1
HNAN
I 18-24
•
•
McKean
Dubois & François I
Beaumont
I
30-36
Ditto
Ditto
+00:
42
48
48
243M2 2 2 1
76
7호
​Pennant.
Syenite.
3 1/1/1
6-7
Pennant.
4-4/3/
Ditto.
Quartz and schist.
51%
Dolcoath
Barrow
30
11
Ballacorkish.
Darlington
42-54
2720
II-12
Foxdale
Ditto
36
3 1/2
16
Ditto
Barrow
39
1621
Minera
•
Darlington
30
15
Ballacorkish Shaft
Ditto
50-60
28
16
56
Hard silicious tin lode.
Ditto
Killas.
Hard silicious tin lode.
Hard tough Clay-Slate
Quartz, spar, & spathose iron.
Hard bastard Granite.
Limestone, quartz, &c.
Clay-Slate veined with quartz.
Laxey .
Ingersoll
30
:
Name.
4
3
4
6
TABLE IV.
COST OF BORING BY MACHINERY.
No. of
Machines.
Cost per Running Fathom.
Machinery.
£ s.
is O O
d.
£
Authority.
Hand.
O
s. d.
3 12
O
Dubois and François.
O
7 6 O
Ditto.
I 15
2 6
Ditto.
·
I 16
3 O
Ditto.
1 & 2
•
7 O
II IO
Barkell.
I
•
7 O
12 O
Ditto.
ни
I
ΙΟ
O
O
17 O
Ditto.
I
7
10
O*
I I
O
Ditto.
1 & 2
9
10
O*
15
O
Ball.
17
0
25
Provis.
4
32 O
27
Ditto.
2
50 0 0
90 O
Ditto.
83 10 OT 100 оо
Ditto.
Cockerill Works
Noeux
Gosson Lagasse
Chartreuse and Violette
Ballacorkish
Foxdale
Ditto
Laxey
Minera
Dolcoath
•
Carn Brea Level
Ditto Shaft
West Tolgus
•
The cost of driving and sinking by hand labour, and with boring
machinery, can only be approximately stated. The heading "hand price,"
* Exclusive of cost of compressing air.
† Including estimated cost of compressing air.
CHAP. II.]
WORKS EXECUTED BY BORING-MACHINES.
557
in the table, is in most instances the estimated price of the ground. The
cost of compressing the air is also in some cases associated with other costs
which cannot well be separated.
In each of the examples, but one, there is a difference in favour of
machinery sufficient, it may be assumed, to include the redemption of the
boring-machines, as well as the cost of maintaining the plant.
The relative proportion between the rate of driving by hand, and with
machinery in different varieties of rock, as well as the comparative cost of
the work, exclusive of cost of compressing air, is approximately as follows:-
Rate of Advance.
By hand
By machinery
Hard Grit
and Quartzite.
Schist.
Ordinary
Sandstone.
Hard Grit.
20
IO
•
30
•
25
5
18
•
3
[2
0.9
. 8.8.
0.65
•
0.50
Taking the hand price as a unit of comparison,
the cost of the work by machinery, exclusive
of cost of compressing air
•
It will be seen from the above statement that rock-boring machines afford
the best results when boring holes in hard ground. In Schist, the rate of
driving is only reckoned one-half more than that obtainable by hand labour,
and the cost one-tenth less, whereas in hard grit and quartzite the rate of
driving is threefold greater, and the cost one-half less.
TABLE V.
SUNDRY PARTICULARS CONNECTED WITH DIFFERENT WORKS WHICH HAVE BEEN EXECUTED
BY MEANS OF ROCK-BORING MACHINERY.
Name.
Diameter of Shot-hole
at Bottom in Inches.
Depth of Shot-holes in
Inches.
Area of Level in Square
Feet.
Average Number of Shot-
holes made in Face for
one Cut or Sink.
Number of Boring
Machines employed.
Number of Square Feet
of Face to one Boring
Machine.
Name of Machines
employed.
Mont Cenis
Mustconetcong
St. Gothard
Portskewet
Altenberg
Perseberg
Salzbach
Anzin
Marie Colliery
Pierre Dennis
Stahlberg
Gonley Colliery
Drybrook
Sir Francis Level
Minera Shaft.
-
K
•
/లు
30-48
83
108-110
216
55-65
36
ΙΟ
∞
2
I
142-84
24-30
20-36
72
26
64
12-18
52 1/10 10-12
1100
24
72
221
32
26 1/1/0
72
81
55
12
{
Sommeiller.
Ingersoll.
Ferroux, Dubois.
François, McKean.
Geach.
Sachs.
Bergström.
H
21-24 175/1
10
I
175
I
М
-PITOW
72
60-72 57
34
19
30
72
52 1/1/
34-30 40
ཆ:ྂཎྜ
4
14
Dubois & François.
4
83
Ditto.
4
13
Ditto.
I
40
Sachs.
30-40
64
I
64
Ditto.
40-50
40
•
48-60 35
www.
34
I
40
Darlington.
30
I
35
McKean.
30-36 56
Minera Level
32-36
46
36
24-26
2
28
I-2
22-23
Johann Colliery
58 228
6 38
Ballacorkish Shaft .
40-60
86 22-24
2
43
Ballacorkish Level .
=
40-50
Carn Brea
42
South Crofty
•
Cwmbran
30-36
Dolcoath
Maesteg
Foxdale.
Laxey
Blanzy
•
48-66
DAY: BA
45/
49
17-18
16-20
I-2
ΙΟ
45
20
4121d
∞ 3 2 2
342 H
FATH
22/
12
I
35
I
45
64 16-18
4
16
•
I
42
24
I
42
•
I
31 31/10
16-20
I
•55621
311
H
50
16-18
2-3
25
Darlington.
Ditto.
Sachs.
Darlington.
Ditto.
Beaumont.
McKean.
The Barrow.
Beaumont.
Darlington & Barrow.
Ingersoll.
Darlington.
558
[BOOK III.
PRACTICAL MINING.
In reference to the question as to the comparative advantages obtainable
from the employment of power drills over that of hand labour, some general
facts present themselves of the greatest importance to the miner.
1. Any given work may in most cases be executed at a direct cost not
exceeding that of ordinary hand labour, and frequently at a less cost, pro-
vided the ground be unusually hard for the boring tool.
2. The rate of progress which may be accomplished by means of
machinery can be reckoned from three to four times greater than that obtain-
able by hand labour. In other words, as much exploratory work may be
done in one year as is practicable in three without the use of machinery.
3. Levels may be driven a considerable distance without the necessity of
sinking shafts or winzes for ventilating purposes.
4. Miners working in connection with pneumatic boring-machines are
continually supplied with an abundance of fresh air.
5. The speed attainable through the efficient use of boring-machines will
materially tend to quicken the chances of successful results for the capi-
talists, and to lessen the amount of the capital expenditure which otherwise
would be required. Instead of the dead charges incident to an undertaking
extending over a period of nine or ten years, they need not continue longer
than three or four; that is, to accomplish an equal amount of work.
Levels and shafts free from water will always be driven and sunk more
quickly than levels and shafts charged with water; but a great deal may be
done to quicken the rate of speed in a sump-shaft by eliminating as far as
possible the causes which will conduce to hindrances before commencing the
work, and getting rid of delays as soon as they may occur.
The number of machines and hands which it may be desirable to employ
in sinking a shaft or driving a level are matters which must be met by the
necessities of each particular case. Probably two machines and nine men
in a level will be generally sufficient. But three or four machines may run
together. Unless, however, the hands are well trained to their work, and
adequate provision is made for lessening the time of the charging, blasting,
and waggoning operations, the speed and money result will not be in pro-
portion to that attainable by the smaller number of machines.
Fig. 143 illustrates a small plant of rock-boring machinery. On the left
hand the compressor is shown communicating with a receiver set towards
the right-hand side of the building. This receiver is fitted with a safety-
valve to discharge any air which may come from the compressor in excess of
the required pressure. From the receiver a main of pipes passes down the
shaft, and from this main three smaller mains branch off at right angles into
as many levels. In the first level a boring-machine is supposed to be
applied to underhand stoping, in the second and third levels to perforating the
forebreast with shot-holes which are to be subsequently charged and blasted.
The economic result consequent on the employment of rock-boring
machinery will depend mainly upon the proper and effective organization of
the work.
The boring-machine must necessarily be a reliable and good one, con-
structed so as to withstand the heavy wear and tear to which it may be
subjected. It must also be of sufficient power to drill the holes moderately
quickly. It is, however, of almost equal importance that the apparatus on

CHAP. II.] PLANT OF ROCK-BORING MACHINERY.
559
which the machines are mounted should be of ample strength for holding
them firmly to their work when under the influence of a rapid succession of
Fig. 143.
blows, while it should be so contrived as to afford every facility for drilling
shot-holes in any required position.
560
[BOOK III.
PRACTICAL MINING.
For permanent use very high-speed compressors are not desirable, but
compressors arranged to withstand all the reasonable wear that can be
imposed upon them, and at the same time constructed so as to afford a
maximum result for the power expended to produce it.
For the purpose of removing the centre cut the strongest explosive should
be employed, and particular care taken to detonate, not to burn, the explosive.
Taking the average bottom diameter of most of the shot-holes bored by
the various machines to be 1 inch, it would be important to ascertain if, by
increasing their diameter, a lesser number would not suffice for removing
the entire cut or sink.
In such case the fewer holes, drilled with machines of increased power,
might be valued with the greater cost of the explosive which would probably
be required; and in this way the relative advantages of varying the number
and diameter of holes could be usefully determined.
Shot-holes should be bored as deep as they may be found capable of effect-
ing the removal of the ground, having also regard to the time of boring the
holes, which usually increases with increase of depth.
Electric blasting offers in itself an element of security and success. It
would be well, therefore, to ascertain what increase in the normal rate of
speed would result, and what percentage of explosive material might be
economised, by the use of electric over safety-fuse.
It is scarcely open to doubt that the time is near at hand when boring-
machines will form a part of every mining plant; that is, in mines where
a considerable amount of work is intended to be done in moderately hard
ground. In all cases the drilling-machines and plant should be under the
control of a mechanical engineer, rendered responsible for the efficient
performance of the apparatus and the economical conduct of the work.
A.D.
CHRONOLOGICAL TABLE
OF SOME OF THE MOST IMPORTANT EVENTS CONCERNING EXPLOSIVES,
BORING SHOT-HOLES, AND BLASTING GROUND.
Partly compiled by Rziha and Drinker, and supplemented with additional information.
1280. Albert Magnus, the German friar, describes an explosive powder.
1284. Roger Bacon notices the composition of an explosive powder.
1324. Berthold Schwarz is said to have invented gunpowder.
1412. Gunpowder manufactured in England.
1613. Martin Weigel, mining superintendent of Freyberg, proposed drilling and blasting in mines.
1670. German miners introduced blasting into England.
1685. Tamping with clay known in Saxony.
1687. Lumbe introduced into the Harz tamping with clay, and straws filled with powder for firing the
shot-holes.
1688. Singer, of Clausthal, employed small firing-tubes of hard wood.
1689. Thomas Epsly, senr., of Chilchampton, Bath, introduced blasting of rocks in Cornwall.
""
Luft, of Clausthal, used pasteboard cartridges.
1717. Fritsch proposed to save powder, and to break the rock by wedges driven into the bore-holes.
1725. At this date the effect of simultaneous firing of several shots was known.
1749. Hungarian miners first introduced the chisel-bit drill into the Harz. For a period of one hundred
and thirty-six years from Weigel's day to this date 1749, all drilling had been done by means
of crown and cone "bits.”
1759. Drilling with a chisel-bit introduced into Saxony.
1760. Thunberg introduced into Sweden tamping with wedges.
1791. Le Plat used sand as a tamping.
1795. Humboldt proposed making the shot-holes wider at the bottom (of a conical shape).
CHAP. II.]
CHRONOLOGICAL TABLE.
561
1811. Spangenberg, of Sahl, used wooden tamping-rods, also wooden needles and soft clay for tamping.
1813. Trevithick invented a rotating boring-machine, which was made at Hayle Foundry, Cornwall, and
put into operation at some Limestone quarries near Plymouth.
1823. Harris fired a blast by the electric spark.
1829. Needles made of a composition of lead and tin used in the district of Ehrenfridersdorf.
""
Moses Shaw, of New York, fired several charges of powder simultaneously by passing an electric
spark through a priming composed of the fulminate of silver.
1831. Bickford, of Camborne, invented the safety-fuse.
1834. Pischel proposed ignition of blasting powder by means of percussion.
1838. Prideaux used oxyhydrogen gas for deepening bore-holes, and with it burnt a hole at the rate of
one-eighth of an inch per minute.
1839. Hague injected water into air-compressing cylinders.
1840. Borer holes made with rotary drills at Lankowitz.
Cast-steel borers used in the Derbyshire mines.
1844. Brunton, of Cornwall, proposed using compressed air for working drill hammers, the air after use
to improve ventilation.
1845. Cast-steel drills tested at Freyberg.
1846. Schonbein exhibited a sample of gun-cotton at the British Association.
1847. Sobrero discovered nitro-glycerine.
1849. Randolph, of Glasgow, introduced into an air compressor a spray of water for cooling the air during
""
its compression.
Couch, of Philadelphia, patented a "lance" percussion drill.
1850. Robert Hunt, F.R.S., made low-tension electric fuses, which were used in sinking a pit at the
Abercarn Colliery, South Wales, the firing of the fuses being effected by means of an electric
battery.
1851. Fowle, of Philadelphia, patented a direct-action percussion drill.
Cavé, of Paris, invented a reciprocating percussion drill.
1853. Piatti proposed using compressed air in the construction of the Mont Cenis Tunnel.
1854. Bartlett's rock drill tried at the Mont Cenis Tunnel.
Experiments with compressed air made at the Mont Cenis Tunnel.
Schumann invented his percussion power-drill.
1857. Schumann's drill employed in the Freyberg mines.
Sommeiller invented a drill for use in the Mont Cenis Tunnel.
"
""
Ebner employed a frictional-machine for blasting.
Schwarzkopf's drill tried at Bingen.
1861. On the 1st of January, Sommeiller's perfected drill commenced to work at the Mont Cenis Tunnel.
Lisbet applied his machine in boring soft rock, coal, soft Limestone, &c.
1862. Bornhardt's air-tight electric firing-machine brought into successful use.
1863. Edward Crease introduced his rock-boring machine into the Clogau mines, North Wales.
""
Ditto, invented the double-headed flying piston.
Lows's rock drill invented.
Sachs's rock drill invented.
Nobel applied nitro-glycerine as a blasting agent.
1864. In March, Carl Sachs's machine introduced into the Altenberg mines, Aix-la-Chapelle.
1865. Gun-cotton tried at Hoosac Tunnel.
1866. Lithofracteur manufactured by Engels, near Cologne.
""
""
Nitro-glycerine tried with great success in the Hoosac Tunnel.
Jordan and Darlington invented the rifle-bar and ratchet-wheel for turning the piston carrying the
drill.
The Burleigh drill successfully introduced at the Hoosac Tunnel.
1867. Jordan and Darlington invented the straight and spiral shot, and double ratchet-wheel, for turning
the drill.
Dynamite patented in England.
"" Doering introduced his boring-machine into the Tincroft mines.
Dubois and François's rock drill invented.
1870. Beaumont and Appleby's diamond boring machinery introduced at the Croesor United Slate quar-
ries, North Wales.
Sir George Denys, Bart., commenced driving an adit for the Old Gang Company, Yorkshire, by
means of the McKean drills.
1873. The Ferroux rock drill invented.
1874.
The Darlington rock drill invented.
The Mowbray mica powder patented.
Electric blasting introduced by Darlington into the Minera mines, Bornhardt's machine, the blast-
ing-stick, and wire electric fuses being employed for that purpose.
Darlington invented a spinning piston machine.
1876. The Beaumont rock drill employed at Carn Brea.
""
Darlington introduced the vertical shaft sinking stand at Minera, and arranged an 8-inch diameter
sinking pump at Ballacorkish, in the Isle of Man, for carrying the boring-machines.
The rock-boring machines in use are, in many of their details, alike.
The cylinders are mounted in cradles, and are advanced and withdrawn by
a long screw, while the pistons are generally reciprocated by means of a
562
[BOOK III.
PRACTICAL MINING.
tappet or "flying valve." The peculiarities of the Ingersoll drill consists in
effecting the movement of an ordinary slide valve by means of tappets enter-
ing into and set at each end of the cylinder. In the Barrow machine the
valve is shifted and the movement of the piston reversed by a tappet set
between a double-headed piston engaging in a plate valve. The Burleigh
and Cranston machines are types of each other. The valve in each is
shifted by a tappet set at the rear end of the piston-rod. In the McKean
drill the valve is semi-rotated by a tappet set on a back piston rod, while the
turning of the piston and tool is effected by spiral gear at the end and out-
side of the cylinder. The Schram, Eclipse, Cornish, and Beaumont machines
are fitted with what may be designated piston-flying valves, to which the
pressure fluid is distributed by the main piston. In each and all of the
machines in use, the compressed air is admitted to the lower side of the
piston before the blow is struck so as to reverse the action of the machine.
Leschot, Taverdon, Pittar, and Beaumont have each contrived diamond
drills and applied them to the boring of shot-holes. Hand boring-machines
have been devised by Jordan and Macdermott. The former employs a
cylinder in which the piston is lifted by a "snail cam." Two points are
accomplished by this movement-the piston and tool are turned, the air
is compressed within the cylinder, and when the cam is released from the
tappet the blow is smartly struck.
PERCUSSIVE ROCK-BORING MACHINES IN USE, AND CHARACTERISTICS
(a) Tappet-worked valve
(b) Flying valve
OF SAME.
Typical Machines.
II machines
(e) Ordinary D valve
•
7
4
(d) Tappet and Flying valve
2
Advance of
Machine.
(c) Valveless
•
I machine
I ""
2
(ƒ) Tappet and semi-rotary valve
(g) Valve independent of machine
Name of
Machine.
(c)
Inventor of Typical
Rotating Device.
Wheel and
Automatic Darlington Rifled Bar
Advance of
Machine.
Hand
Automatic and
Hand
Name of
Machine.
(a)
Burleigh
Inventor of Typical
Rotating Device.
Burleigh
Wheel and
Rifled Bar
Dunn
Cranston
Hand
Roanhead
Barrow
Hand
Geach
and Hand
""
Darlington
Hand
Levet
Levet
""
""
""
Excelsior
Brydon and
Davidson
}|{
Ingersoll
Grunez
Rand and
Waring
Burleigh
Wheel and
Rifled Bar
""
>>
Wheel and
Rifled Bar*
}
}
""
Burleigh
Wheel and
Rifled Bar
}
Automatic
and Hand
Hand
François
Ditto (Anzin)
(d)
Dubois &
Dubois and
Hand
François
Burleigh
Meyer
Automatic
(e)
Ъ
Sachs
Sachs
Automatic
Beaumont
Wheel and
Rifled Bar
Automatic
Schram
Hand
Edwards
{
Wheel and
Rifled Bar
Hand
Automatic
"
Darlington
Frohlich
Eclipse
Cornish
Rock Drill
"
(g)
Ferroux
Ferroux
* Wheel and Rifled Bar in Italics invented by Jordan and Darlington, 1866.
(f)
McKean
Ullathorne
McKean
Wheel and
Automatic
Hand
(Champion) Rifled Bar)
Automatic
CHAP. II.]
SUBTERRANEAN EXPLORATIONS.
563
EXPLORATION.—Everything necessary having been done to warrant
further subterranean working, so as to extract the ores from the mineral veins
or beds, with the least waste and the utmost economy; the manner in which
excavations are to be made depends entirely on the nature of the ground
which is to be opened. Werner adopted the following classification, and he
selected for each kind of ground a special tool-or a process of working—
which he thought the appropriate mode of proceeding
a.-Loose or running ground (vegetable earth, sand, and earthy deposits) require the shovel.
b.-Soft or fair ground (strongly coherent sands, or clay decomposing masses, disintegrating Granite,
friable veinstone) require the pick.
c.-Semi-hard ground (some Limestones, Killas, copper, Slate, gypsum, mineralised Granites, rocks
generally which are partially decomposing) require the gad (Saxon).
d.-Hard ground (Granite, Êlvan, Gneiss, Porphyry, Basalt, Hornblende, Serpentine, &c.) require
blasting.
-Very hard or tight ground (this would apply to some highly silicious rocks, to some con-
glomerates, &c. &c.) by means of fire.
f.—Soluble rocks (detrital matter and disintegrated masses, massive deposits) by means of water.
This classification does not entirely hold good in the present day. The
application of fire, for example, is almost obsolete, indeed it is only under the
most peculiar cases that it is ever used. The removal of country (especially
deposits of gravel or soft ground) by water applies only to the process of
hushing in the north of England, and to hydraulic mining, as it is employed
in America and Australia, for the removal of auriferous deposits. When
we come to speak of tools, a description of the varieties demanded for
particular work will be given.
There will be some advantage in referring to the ordinary modes used
by the older miners, notwithstanding the notices already given.
*
In 1671, a writer, who appears to have been well acquainted with the
mines of Cornwall and Devonshire, published in the "Philosophical Transac-
tions some details of the mode of working mines, at that time, when
mining was in a very primitive state. Levels were then driven at about five
fathoms under each other; and the water was raised either to the adit, or to
the surface, by means of " a winder and keeble, or leathern bags, pumps, or
buckets."
"When we have found our load, the essay hatch (i.e. a shallow pit as sunk
in costeening) exchanges its name for that of a tin shaft or tin hatch, which we
sink down about a fathom, and then leave a little long square place, termed
a shamble, and so continue sinking from east to west, till we find the load to
grow too small, or to degenerate into some kind of weed, as mundick or maxy,
&c. Then we begin to drive east and west-as the goodness of the load or
convenience of the hill invite-which we term a drift, 3 feet over and 7
feet high, but in case the load be not broad enough of itself, then we
usually break down the deads (unprofitable parts of the lode) first on the
north side of the load, and then we begin to rip the load itself. The beele-
ment rip up the deads and ore, the shovel men convey it off and land it, by
casting it up with shovels from one shamble to another, unless we have a
winder (windlass) with two keebles, which as one comes up the other goes
down."
The Cornish are essentially a Celtic race.
Philosophical Transactions," No. 69, p. 2096.
The mixture of Oriental, of
† Bal-men, men working a bal or mine.
00
564
[BOOK III.
PRACTICAL MINING.
Saxon, of Danish, and of Spanish blood can be traced in some districts-more
especially on the Cornish coast; but, in the mining districts the superstitions
of the Celts still linger, and we find the miner persistently walking in the foot-
steps of his ancestors. One striking characteristic is the tenacity with which
the miner pursues a certain course of action "because his father did so before
him." It becomes, therefore, interesting to examine the changes which
have taken place during a series of years. The quotation just given, as the
mode of working in 1671, describes the exploration of mines, much as it is
explained by Carew in the latter part of the sixteenth century, and he was
greatly assisted in this by Sir Francis Godolphin, who was regarded in
those days as a high-class authority on Mining.
In 1758 Borlase published his "Natural History." We have, therefore, an
example of mining, as practised at that time, in the following :—
"The lode being found," Borlase says, "three things are necessary to be
considered by the miner: first, to dispose of the barren rock and rubble;
secondly, to discharge the water, which every lode yields more or less, and
generally in quantities sufficient to obstruct the labourer if not duly attended
to; thirdly, to raise the tin [or copper; the copper mines of Cornwall were of
small importance in the time of Dr. Borlase]; and all these are easily
performed when the workings are near the surface; but the difficulties
increase with the depth, and skill and care become still more and more
necessary. Indeed all the mechanical powers, the most forcible engines,
and the utmost sagacity of the chief miners, is often too little and vain, where
the workings are deep and many. Anciently they worked for tin, especially
when found disposed on floors, by laying open all the ground, as they do
now in stone quarries. Several of these openings, called coffens, are still to
be seen in the parish of St. Just and elsewhere; but this being a method too
operose and extensive, it was not long, we may imagine, before the tinners
learned to make passages into the bowels of the Earth, of dimensions no more
than necessary, to examine the lodes and bring off the ore, and this is what is
properly called mining. The arts necessary to mining are many, and every
mine almost requires a peculiar management. Mining, therefore, must be
learned by practice, by experience, and masters-not from books, the rules of
which, though ever so just, must be frequently suspended, altered, qualified,
and superseded, according as the various circumstances require.”
Sir H. de la Beche* gives a carefully prepared abstract of Borlase's
description of Pool mine in Illogan, and describes the mine section en-
graved in the "Natural History," which description it will be an advantage
to quote:-
"To afford a view of the manner in which a mine was worked in his time,
Borlase selected the Pool mine, in the parish of Illogan. In that mine there
were seven shafts upon the lode, upon one of which there was a fire-engine
working the pumps and raising the water of the mine, which it unwatered to
the adit level, 20 fathoms from the surface. Another shaft had a whim on it,
probably a water-whim from its name; and the others had common winzes
at their heads, though two of them must have been 45 fathoms and one 55
fathoms deep. The lode was worked by stoping, or in steps, so that many
men could readily be employed at the same time upon it—a practice probably
Geological Report on Cornwall, Devon, and West Somerset." By Henry T. de la Beche, F.A.S.
*
CHAP. II.]
MINING DESCRIBED BY BORLASE, ETC.
565
ancient, and derived from working the open lodes by stages, the miners
throwing the ore and rubbish from one stage to another until they reached
the surface, as has been supposed by Pryce. The walls of the lode were
supported by timber, and planks were laid upon them in proper places, on
which the deads, or unprofitable parts of the workings, were thrown. Captains
superintended the work, and saw that it was properly conducted, and it
appears that they employed the magnetic compass, or dial, in ascertaining
the bearings of work to be executed, such as sinking shafts, &c.
"With respect to the machinery employed to unwater the mine, Borlase
enumerates the water-whim, the rag and chain pump, the water-wheels and bobs,
and the fire-engine, independently of the hand and forcing-pumps for small
depths. The whim seems to have been the same with the common horse-
whim of the present day, employed to draw ores from moderate depths, the
only difference being that water was raised in the kibbles, or buckets,
instead of ore. The rag and chain pump consisted of an iron chain, furnished
at intervals of two or three feet with knobs of cloth, stiffened with leather,
which, being turned round by a wheel two or three feet in diameter, furnished
with iron spikes that fitted into the links of the chain, and made to pass
through a wooden pump-cylinder about 6 or 8 inches in diameter and 12 or
15 feet long, brought up the water which rose up into the bottom of this
wooden cylinder between the knobs of rag. The surface of the water to be
pumped out was necessarily some height above the bottom of the cylinder,
and beneath it the chain, with its rag-knobs dipped, in its passage round the
wheel and through the pump-cylinder. These pumps were worked by hand
in the mines, and afforded a stream of water in proportion to the circum-
volution of the wheel turned. Rag and chain pumps were then also, it
appears, worked by small water-wheels in the tin-stream works near St.
Austell. The water-wheels with bobs sometimes worked pumps with brass
cylinders, and seem to have been much used, as Borlase complains that from
the great want of water in summer, many of these engines could not work
from May or June to October-a great hindrance, it is observed, to the mines.
at that season of the year."
Pryce published his "Mineralogia Cornubiensis" in 1778. He was a better
miner than Borlase, and consequently his description is more exact. He
supposes "The present methods of working of tin mines by deep shafts, and
by driving and stopeing under the firm ground, has been practised more
than three hundred years past. Prior to those means for raising of tin, they
wrought a vein from the bryle to the depth of 8 or 10 fathoms, all open to
grass very much like the fosse of an entrenchment. This was performed by
mere dint of labour, when men worked for one-third of the wage they now
have. By that method they had no use for foreign timber, neither were they
acquainted with the use of hemp, or gunpowder." After describing the
process of shammeling, which has been already sufficiently explained, Pryce
says: "This, with streaming, I take to be the plain simple state of mining in
general three centuries ago, and from hence is derived the custom of shammel-
ing both above and under ground at this time; for in the clearing of attle
(deads) or filling the kibble with ore the miners prefer a shammel, which is
a stage of boards, for the more light and easy use of their shovels. . . .
The method of shammeling, even in those moderate times, has been expen-
0 0 2
566
[BOOK III.
PRACTICAL MINING.
sive where a very small lode of tin occurred in a hard country. To remove
a dense hard stratum of rocky overburden must be very fatiguing and
perplexing; therefore they found it most advisable to sink shafts down upon
the lode, to cut it at some depth, and then to drive and stope east and
west, upon the course of the lode.
We shall now set forth the first
arrangement for working a mine, in order to which the principal thing to be
N
thought of, is a shaft to
cut the lode at twenty
or thirty fathoms deep,
if it is possible to be
done. Here it is ne-
W
Fig. 144.
E
cessary to form some
judgment of the incli-
nation or underlie of the lode, before we attempt to sink a shaft; for
instance, if the lode underlies to the north about 3 feet in a fathom, and a
shaft is designed to come down upon the lode in 20 fathoms sinking, the
miner must go off north, from the back of the lode, full 10 fathoms and there
pitch his shaft, by which means he is certain to cut the lode in the shaft, about
20 fathoms deep; because for every fathom the lode descends in a perpen-
A
10 fm
Fig. 145.
B
C
10fm
D
20fm
harder the ground is, the longer and
dicular line, it is also gone 3 feet
to the north of the perpendicular."
But to render this more con-
spicuous, let the line W E, Fig. 144,
represent the back, or surface of a
lode pointing east and west, and
whose underlie is north; by sink-
ing a shaft upon this back, it will
soon be deserted by the lode,
which is gone farther north 3 feet
for every fathom that is sunk upon
that line; so that when the lode
is 20 fathoms deep it must be gone
north to the imaginary line N,
where another shaft must be
sunk to cut the lode at that
depth.
"A proper working shaft upon
which a whim may be erected, if
necessary, should be 6 feet long
and 4 wide, where large water-
barrels may be wanted; and the
wider the shaft ought to be, that
the men may have the more liberty to work and break it, the area of a
large shaft being more easy to rip up where the ground is hardest, than of a
small one, where it is more confined together, and breaks in shreds of stone.
A fire-engine shaft ought to be at least 9 feet square, or 10 feet by 8;
or, in fact, to contain three shafts in one, which must be partitioned into
three compartments all the way down, from grass to the deepest bottom of
CHAP. II.]
PRYCE'S DESCRIPTION OF MINING.
567
the mine. One half is divided for the pumps and engine work; three feet
of the other is proportioned for a footway to go down and rectify the pumps
when amiss; and the remainder is divided also by a partition of boards for
a whim-shaft to draw the deads and ore from the sump of the mine."
Pryce gives the number of men required; but as this must be regulated
by the conditions of the mine, and determined by the experience of the
agent or engineer, it is useless to quote his remarks. He proceeds :-
"The working shaft being sunk downright until it cuts the lode, they
open the vein or sink the body of the shaft through it; and if they think the
vein is worth following, they sink the same shaft deeper in the body of the
lode, upon its inclination or underlie, whence the shaft becomes, and bears
the name of an underlier; at the same time they turn house, as they call it,
from the bottom of their perpendicular, or from the top or beginning of the
underlie. So that, when the lode is well impregnated, they turn house by
driving or working horizontally on the course of the vein, either to the east
or to the west, or both, as they find it most likely to answer their expec-
tations, in order to make a fuller trial and discovery. Where the lode
answers well, in thus driving upon it, they continue to do so, till they are
prevented by want of air, or till the end of their workings is too far from the
shaft, and the expense of rolling back the stuff to the shaft is great and
incommodious; then it is proper to put down another shaft.
Mean-
while they are mindful to sink their first shaft, in order that they may work
away the lode from thence in stopes, and have a little sump or pit in that
place, as a bason for receiving the water of the lode . . . . Adit.-If the
lode lies in ascending ground, they quit the vein for the present, and go
down to the most convenient place in the valley, and from thence they bring
in a trench, drain, or conduit, which they call an adit, tye, or level, and so
they work, and drive this passage through the hill in a right line to the lode,
with very little loss of the level they began from.”
The conditions remain at the present day much the same as those which
prevailed when Pryce wrote, and his remarks are applicable to our modern
mines. If the run of the veins is from east to west, or nearly so, the shortest
and cheapest adit will be one driven from north or south, unless very hard
igneous rocks intervene. If this should occur it will be advisable to seek for
a cross course or cross gossan. If the gossan does not exceed 3 feet in
width it is considered favourable, because the adit may be driven without
the use of timber to support the sides.
Where the rock through which the adit is to be driven is much fractured,
or is in a loose, decomposed state, it will be necessary to support the sides
and the roof with timber. Sometimes it is considered advantageous to con-
struct an arch from the stones broken out of the workings. As a proof of
the small advances which have been made in the construction of levels, it
may be stated that in many parts of the country very ancient adits have
been discovered, constructed with stones which have been carefully cut and
squared.
The adit, as it is to be used for draining all those portions of the mine
which are above the level found to be convenient for the discharge of the
water, is usually about 6 feet high and a yard wide. Under special con-
568
[BOOK III.
PRACTICAL MINING.
ditions the height and breadth are increased. The depth at which the adit
is driven depends upon the lowest level obtainable in a valley, or on the sea-
shore.
If a mine has been started by sinking a shaft in a hill, for the purpose of
removing the water which may accumulate in such a shaft, and thus impede
the work of sinking, it is the most economical process to drive a level from
the base of the hill so that the water draining from above may flow out. Of
course this drain is only available for such gathering of waters from above.
When, by sinking the shaft, the accumulation is below the adit, the water is
drawn up to it by some mechanical means; thus the labour is saved of
lifting the water through the space which is between the adit and the mouth
of the shaft on the hill.
In driving an adit it becomes necessary, after the hill has been pierced
to a certain distance, to adopt some arrangement by which the miners may
be supplied with fresh and pure air. By the processes of respiration, and of
combustion from the burning of candles, the air is soon contaminated with
carbonic acid.
One plan of effecting the ventilation of the end of an adit is to lay boards, H,
Fig. 146.
a
B
A
on the bottom of
the adit from its
mouth, A, Fig. 146,
to its end E, so that
a hollow space is
left below them,
and to stop the
spaces between
them with clay.
This arrangement
is called a soller,
and it forms a
channel through
which the air flows and reaches the men at H, when it returns and flows up
the shaft D. A series of iron pipes, or even pipes of canvas, may be used as
temporary expedients for obtaining the same end. To make the matter clearer
with regard to driving and sollaring an adit, let us suppose A to be the tail of
an adit, all open to grass till it enters the hill, a little farther on they put down
an adit-shaft at B for air or for the removal of deads from the mine. The
next shaft, C, is sunk for the same purpose, and so is D, which may be
regarded as the working shaft, the refuse being drawn up through this shaft
by a windlass fixed at the surface. The apparatus above the shaft C is for
the purposes of ventilation. The wind trumpet-mouth, a, is kept opposite
the wind, which, blowing into it, passes down the pipe G into the adit. If this
does not prove sufficient, a soller is placed as described along the bottom,
which discharges the air up the shaft, there being a door at K. Sir Robert
Moray* describes a method practised at Liège for driving adits without
air-shafts. This is done by erecting a chimney 30 feet high, and a furnace
at the tail of the adit, from whence an air-pipe is continued through the
Philosophical Transactions," No. 5.
CHAP. II.]
THE PROCESS OF SINKING SHAFTS.
569
adit, whereby all foul air is drawn by the fire into the chimney, so that a
current is generated, and this removes all the impure air from the adit.
This mode of ventilation is frequently used in our collieries, but it is rarely
adopted in our metal mines.
Adits are not generally of any considerable length, beyond the extent of
the sett; but sometimes, when several mines. have been embraced within
the drainage system, they have been driven for many miles. If the adit
passes through hard ground, all the conditions will be of the same general
character as those for driving levels underground and for the ordinary
processes of mining.
Shafts.-Access to a mine is always by means of a shaft (called in France
puits or bure; in German, schacht). The question as to the best position for a
shaft is a very important one, and this can only be determined by bringing
all the advantages of experience to bear on the question. It is usual to
sink what may be regarded as the principal shaft, as near as can be
determined to the probable centre of the sett and the middle of the workings.
This shaft is commonly called by the miners the sump-shaft, because the
largest quantity of the water is drawn through it, or the engine-shaft, as the
engine will be fixed in it. The most satisfactory position for a shaft will be
regulated by several considerations, depending in a great degree on the
character of the surface and the nature of the rock to be pierced.
This being settled, the next question to be determined is, whether the
shaft shall be vertical or inclined. A vertical shaft is for almost all practical
purposes the most convenient; but, it is sometimes thought to be advanta-
geous to cut it upon the underlie of the lode. The advantages of the truly
vertical shaft are considerable, especially where the shaft is to be used for
pumping machinery. Considerable inconvenience constantly attends any
deviation from the vertical to an inclined direction; as a general rule, too, a
vertical shaft is the more economical for winding. It is thought by many
miners that sinking the shaft on the underlie of the lode has its advantages
in the facility afforded for the removal of the ore. These are, however,
questions which can only be solved on the mine, after the peculiar character of
the strata through which the shaft will pass has been ascertained, and the
dip of the lode determined.
Shafts are of several kinds. The deepest shaft, and most important,
is that one which is to be used for pumping water from the mine. The
shaft for winding, which is frequently not so deep, is often convenient to
use for pumping, either by a separate engine or by rods from the pump-shaft;
it is then termed a flat-rod shaft.
If a lode inclines much from the perpendicular, it is sometimes considered
the best course to sink on the lode rather than in the dead ground; such
shafts are termed oblique, inclined, or underlay shafts, while those that are
perpendicular are termed "right shafts."
In Cornwall, where the lodes are of moderate breadth, and the "country"
(¿.e. the enclosing rock) of ordinary hardness, by opening the lode to a certain
length, you have a shaft corresponding to the size of the lode, and generally
the ore thus obtained will meet the expenses of sinking. This is often im-
portant, as at the same time as the process of sinking is going on, the lode
570
[BOOK III.
PRACTICAL MINING.
itself is being explored. It is still a question amongst many practical
miners, whether it is more economical to sink a shaft upon the lode, or to
cut a perpendicular shaft, and drive out cross cuts at intervals, to explore it.
The general feeling is in favour of vertical shafts. If the sinking is begun on
the back of a lode, it is inconvenient when the lode alters its underlay. This
occasionally takes place suddenly, and there is then difficulty and expense, in
adjusting the cranks of the machinery-so much so, that it is often advisable
to cut away the angle on the foot-wall side. There are many cases in which
it would be difficult to deal with the lode otherwise than by these inclined
shafts. It will, however, always be important to consider when inclined
shafts have fulfilled their purpose, and to study the propriety of cutting a
perpendicular one. If we look at most of the very deep mines, which are of
course the oldest mines, it will be found that they have generally com-
menced by working on the lode, and having reached a productive piece of
ground, the expense is incurred of an entirely new arrangement, and a per-
pendicular shaft sunk from the surface, to intersect the lode at a considerable
depth. At Tresavean mine the principal shaft intersects the lode at a depth
of 250 fathoms. Mr. W. W. Smyth gives the following remarkable example
of the changes in direction in a shaft: "A rectangular shaft was carried
down to the adit level at a depth of 20 fathoms; there it met the lode dip-
ping towards the south, and was sunk on, until at the 14-fathom level below
the adit it met a lode dipping the other way; the miners preferred the look
of the latter, and sunk on it with much regularity to the 112 fathoms, where
they again met with a lode dipping in the opposite direction and followed
it." This is, however, not a common case, and it should not have been
allowed to exist. In some cases inclined shafts are very convenient, and
ง
A
ab
B
d
absolutely necessary where the mine is
worked under the sea. The inclined shaft
at Botallack is a fine example of this. It
gave a convenient mode of ascending and
descending, to the men; it furnished an
effective mode of ventilation; and was
very convenient for loading the waggons
and drawing the ores to the surface.
If you have a lode on the side of a
hill, which is likely to be productive at a
moderate depth, dipping in the same
direction as the slope of the hill, the shaft
a, Fig. 147 (A), will be put down on the
side of the hanging wall to intersect the
lode b in depth. If the lode ac (B) dips con-
trary to the incline of the hill, the miner
may either sink in the lode itself, and
prove it as he proceeds, or he may sink
a perpendicular shaft, b, higher up the
hill than the outcrop of the lode, and
intersect the lode in depth at c, or put down a shaft, d, on the foot-wall side,
Fig. 147.
e
e
and drive out cross cuts e c.
CHAP. II.]
THE CONSTRUCTION OF SHAFTS.
The sizes of shafts vary considerably.
571
In some of the old tin mines
in Cornwall, and in a few of the ancient lead mines in the North and in Wales,
we find shafts only 3 or 4 feet in height and only 2 feet in width. In
metallic mines at the present day the dimensions are 6 feet by 5 feet, or
8 feet by 6 feet; and engine-shafts for pumping and for the ladders for men,
11 feet, 12 feet, and even 13 feet by 8 feet are the usual widths. On the Con-
tinent they construct shafts much larger than this, and even in this country,
in the collieries, they are often of a more extensive diameter. Subsidiary
shafts are generally sunk in a good mine; they are usually placed at intervals
of 20, 30, or 40 fathoms, and are termed winzes. These are useful as sub-
dividing the ground for the convenience of working, and for purposes of
ventilation.
According to the nature of the ground through which a shaft has to be sunk,
the question of the security of its sides has to be carefully considered. It often
happens that a shaft sunk in the older rocks is sufficiently secure, the strata
through which it passes being firm enough to stand without any support,
but as a general rule it is safe to protect the miner from the falling of stones,
by shielding the sides with timber. Any shaft which is only to serve a tem-
porary purpose is always timbered. The timbering is composed of planks
overlapping at their ends, where they are cut obliquely so as to adapt them
to the form of the shaft. This framing has laths or poles placed behind it
for the support of the sides, according to the nature of the ground. They are
fixed in descending order, and are suspended, by means of a series of straps
or bearers, to a carrying frame whose sides are prolonged, so that they rest
either on the surface or in recesses cut in the solid rock. This timbering is
removed frame by frame, as the nature of the ground will permit, to make
room for the permanent lining of masonry
as it is built. At the Alport mines, in
Derbyshire, where the finished shaft was
12 feet diameter and circular in form, this
method was adopted, the walling of the
shaft being of the stones of the district
very carefully squared.
When timbering is intended to form
a permanent lining, the sections of the
shaft are rectangular, and the frames are
carefully constructed, so as to have them
at invariable distances, and everything is
made very substantial, so that repairs
may be required as seldom as possible.
The size of the lesser side of the rect-
angle is determined by the size of the
kibbles, skips, or cages that are to be used,
while that of the greater side is regulated
by the compartments which may be re-
quired; for example, it may be advisable
་་
Fig. 148.
to secure a compartment of the shaft for ladders, and another for pumping,
or one compartment only may be required. The size of the rectangle having
572
[BOOK III.
PRACTICAL MINING.
been determined, the shaft is laid out so that the longer side is parallel to
the strike of the lode. A set usually is constructed of four pieces of timber
-two wall plates and two end pieces-which may be either round or square.
These sets are fixed vertically, and maintained 5 or 6 feet apart by means of
studdles (supports) placed in the angles (Fig. 148). Where the nature of the
ground admits of it, the sets are built, in series, upon each other. Each
series begins with a set of bearers, the wall plates being made longer than
usual, and their ends are placed in deep recesses made in the solid rock.
Poles or laths are placed behind and jammed by means of wedges. When
the timbering is constructed from above and carried downwards, the sets are
hung from an upper frame by pieces strongly nailed from one set to the
other. A shaft in loose ground may thus be lined with frames close together.
The dividings of the compartments help to stay the wall
plates. The pieces of which the dividers or buntons are
formed are cut as shown in Fig. 149, so that they may be
utilised as stays and serve to support the wall plates. The
Fig. 149.
interior surfaces of the sets and dividers may serve to carry
the guides for the cages, or, if an air-tight casing is required for ventilating
purposes, the casing of boards may be fixed against the sets.
It is usual in timbering a shaft to have the frames pierced, whether of
round or square timber, by taking off half the thickness at the ends. When
ground is reached which is considered as being sufficiently secure to put in
transverse beams as bearers, sometimes this is done on both sides of the
shaft. Frequently a frame of four timbers will be placed on the bearers and
at the corners of the joints, studdles, or struts. If the shaft is of extra size,
a pair of studdles may be placed in the middle; these struts are generally
about 10 feet long; then another frame will be placed on them, and thus
timbering of a more permanent character will be secured. Planks will be
Fig. 150.
driven in around the frames, and any spaces
which may occur will be filled in with waste
wood or stone, so as to prevent the frame-
work falling out of position.
The construction of a shaft is of so much
importance that every care should be taken
to ensure the most perfect method. Walling
should always be preferred to timber; and
although as a temporary arrangement tim-
bering may be employed, yet it is always
advisable to secure a curvilinear form, so as
to be suitable at any time for the employ-
ment of masonry.
The excavation should have a polygonal
form, circumscribed about a circle, and its
diameter should be equal to that intended
for the shaft in a finished state, and allow-
ance must be made for the walling whenever it may be required by adding
to the shaft in width twice the thickness of the walling. It is proper to
cut the pieces of timber obliquely, so as to adapt them to the polygonal
CHAP. II.]
THE TIMBERING OF SHAFTS.
573
form, when the pieces are fitted to overlap each other. The poles supporting
the sides are put in place in descending order, and are suspended by a
series of bearers to a carrying frame, the sides of which are prolonged so that
they rest either on the surface or in recesses formed on the solid rock. This
timbering is removed when masonry is to be built up, frame by frame, so as
to make room for the definite lining of masonry which is intended as a
permanent construction.
Mr. W. W. Smyth, in his "Lectures on Mining," gives the following
instructive description of timbering :-
"Some of the most remarkable timbering of late years is that introduced
in the Comstock district, where the shafts in some instances have been
attempted to be carried through the body of the lode, and maintained there
in the midst of a mass of loose material, and where no expense has been
spared, in some cases, to introduce timber of great size and strength, rendered
necessary by the great dimensions of the shafts. The plan of one of these
shafts is very instructive in this point of view.
"Take a shaft of 24 feet long, fitted with timber 8 to 14 inches square,
having 3-inch planks driven behind the frames all round the sides, forming
what we call 'lagging.' The length of the shaft is divided up into convenient
compartments by means of props, which are of very great importance in pre-
venting the sides from collapsing under the great lateral pressure. These
props are generally placed in steps, two props to each principal frame. They
are very important also for the attachment of the guides for drawing. This
has generally been carried out with round timber; in some mines 14-inch
square timber has been used. In certain mines this timbering has collapsed,
and it has been necessary, after a very short time, to take it out and replace
the sets in close proximity to one another."
When the miner has to deal with loose ground, so that the sides of the
shaft must be supported at once, the principle
adopted should be to place the sets as the shaft
is deepened. Each set is hung from the one
preceding it, and the laths, whether jointed or
otherwise, are driven in behind. The laths
are often driven in advance of the sinking, and
the bottom of the shaft is covered with planks,
so as to allow the excavation of small portions
at a time. The securest plan is to begin an
excavation in the centre of the pit, which
should be lined with boards nailed to a square
frame. This serves a double purpose; it
divides the sinking and forms a well to re-
ceive the water, from which it can be pumped
or otherwise removed without taking up the
Fig. 151.
...
sand. The accompanying woodcut, Fig. 151, represents, in plan and section
parallel to the wall plates, this arrangement, and Fig. 152 gives another
section parallel to the end pieces, showing the vertical pieces which are
placed in the corners and stayed against each other.
There are several questions to be considered relative to the timbering of
574
[BOOK III.
PRACTICAL MINING.
shafts. In the first place is the prime cost of the timber, varying much in
different localities; and then the maintenance of the timbers, which is greatly
affected by the condition of the atmosphere of the shaft. In some mines, and
in certain parts of mines, timber is rapidly affected
with dry rot, especially where the heat is consider-
able and the atmosphere heavy. This rot cannot
always be detected on the surface of the wood; where
it is suspected, it is necessary to scrape off some por-
tion and test by the hammer—if a dull heavy sound
is given at each blow. Experience has shown that
where the ventilation has been carefully looked after,
a fresh atmosphere secured, and water kept trickling
down the timbering, the wood lasts for a consider-
Fig. 152.
able time. In some mines, pipes have been laid on,
with small holes pierced in them, so that the water spirts out upon the
timbering. Under any circumstances the timbering should not be exposed
to much change in temperature, nor should it be allowed to be sometimes
wet and sometimes dry.
Chemical methods of various kinds have been tried for the preservation
of mine timbers: soaking wood in brine, or in water containing sulphate of
copper, as pumped from copper mines, or in which sulphate of iron has been
dissolved. These processes are satisfactory for a short time only. The
surface may be protected, and the salts may influence the wood, to a small
distance beneath the surface, but cracks occur in the wood, and then the
interior suffers from decay of some sort, which is not evident on the
surface. The salts of zinc and of mercury have been recommended, but the
first is not satisfactory, and the latter is too costly to be employed on large
works.
Often, the kreosote process is applied, and without doubt, if care be taken
to secure the absorption of the kreosote, it is a valuable one. It has been
recommended to char the surface of the wood, by exposing it to the action of
flame; if employed, the extremities of the pieces of wood to be buried in
the ground should be perfectly charred.
The application of paint or of tar is not wise, since the decay may go on
under the coating without its being observed.
Of the kinds of timber employed for mining purposes the following may
be especially recommended, amongst the hard woods: white oak, evergreen
oak, chestnut-tree, elm, and beech. White oak is the usual wood employed
for timber work, on account of the dimensions of the balks which can be
obtained and of its great strength; it resists, too, the bad air of mines, and
if it is kept moist it lasts for a long time.
Evergreen oak is smaller than the white oak; it is chiefly found and used
in the South of France. Chestnut-tree attains a large size, but it is destroyed
by the bad air of mines, though it lasts well when placed under water. Elm
and beech are employed where curving is required, either temporarily or
permanently.
Resinous woods include the pine, the fir, and the larch, and several
others but little used; they are distinguished by their long straight trunks.
CHAP. II.]
WALLING OF CIRCULAR SHAFTS.
575
These woods furnish long beams or straight pieces well adapted for
timbering.
Pine is strong and durable when not exposed to warm or impure air, but
it should be kept constantly wet.
The safest course is to employ ingenious and careful timbermen, and leave
all the arrangements of the shafts to them. To experienced men-good
carpenters—the mine manager should entrust the selection of the timber
and its purchase. It is advisable to purchase timber at certain seasons
of the year, especially such as requires storing. If possible, it is advan-
tageous to roof the piles and secure good ventilation. The pile of timber
should have a northern aspect, and the floor on which it is placed should be
gently inclined, so as to facilitate the drainage of rain water.
It must never be forgotten that the decay of timber takes place more
rapidly in a mine than when it is freely exposed to the influence of the air;
therefore it is economical to secure the best possible ventilation. If any
fungoid growth appears, or any cotton-like mould, the wood upon which it
grows should be speedily taken away, as the growth is contagious, and
spreads rapidly to some distance. The following summary, relating to tim-
bering, is from Callon's "Lectures": "A piece of timber has in general to
resist either a longitudinal pressure, which tends to break it by crushing, or
a transverse pressure, which tends to break it by bending. In the first case
it should be set up so that the longitudinal pressure is borne uniformly by
all points on the transverse section, in a direction perpendicular to the
section. If the pieces are long and liable to bend, their resistance may be
materially increased by putting in struts from one frame to the next, or
between the two legs of a frame. In the second case the length should be
diminished as much as possible, and where at all practicable the ends should
be inserted in grooves or hitches. In either case attention should be directed
to giving stability to each piece by placing it in such a position that, if a
small movement of the rock were supposed to take place in the direction of
the resistance under consideration, the effect of the movement would be to
tighten the timber and increase the lode upon it.”*
Walling is a means of support in shafts, which is occasionally used in
metalliferous mines, and very commonly employed in collieries. In the
mines of the older rocks walling is not often required. In most cases the
ordinary rock is compact enough to be trusted to stand without support;
or where it is, from fissures or other defects, rendered necessary to protect the
miner from falls of rock, it has been generally found sufficient to employ
timbering.
The cost of timbering a large shaft will be about one-half the expense of
lining it with masonry. But masonry will, if properly executed, last without
any repairs for many years, whereas a timber lining will require constant
attention and frequent repairs. We must distinguish between two different
kinds of walling. One is building up a lining with dry stones, and the other
is walling with stones carefully cut, squared, and cemented. The materials
employed are rubble-stone, brick and hewn stone, Limestone, the Millstone
*“Lectures on Mining,” delivered at the School of Mines, Paris. By J. Callon, Inspector-General
of Mines. Translated by C. Le Neve Foster, D.Sc., and W. Galloway.
576
[BOOK III.
PRACTICAL MINING.
Grit of the Coal Measures, mica schist, and Slate rocks, which cleave well and
form tolerably uniform blocks. Bricks, if properly made and duly burnt,
possess several advantages. In walling a shaft, hydraulic mortar made thick
should be used as sparingly as possible, so as to produce a continuous film of
cementing material, between each course of stone; and care should be taken
that no interstices should be left. If the stones or bricks are porous, they
should be wetted thoroughly before being used. All spaces behind the walls
left vacant by the removal of timber or otherwise, should be carefully filled
with concrete or a mixture of attle (rubbish) and lime.
Masonry must be constructed in successive courses, in which to break
joint with the preceding. The joints of one course should be so laid that the
mass may be tied firmly together. For this purpose old timbers, cut so that
their lengths are equal to the thickness of the masonry, may be used. The
details of the art of building are beyond the purpose of this volume. Certain
rules which ought to be observed in masonry underground have been
given above. A few other points demand attention. When it is decided
to wall a level, the masonry should be put in in a sufficiently strong
manner. In masonry with parallel joints, the joints should be perpendicular
to the pressure to be supported. In arches, the chord of the arc should be
nearly at right angles to the pressure, and the thickness should increase as
the arch becomes flatter. This applies more especially to collieries, the
conditions of the metalliferous mine rarely demanding this attention. The
following remarks are from the lectures of Mr. W. W. Smyth, and they
are so full of the evidence of a practical acquaintance with the whole
subject, that no abstract of them will serve the desired end :-
"In securing circular shafts, a couple of strong balks will be placed
across the surface ground having the shafts between them. Then the foun-
dation for the timbering of the shaft itself will be by putting in of curbs or
cribs (circular frames of wood), which must obviously consist of a number of
segments. When not required to be permanent, the segments do not require
to be of any great thickness; and, if brickwork is to follow, they will gene-
rally be made of the same size as the bricks. These curbs used to be made
of pieces of oak fitted together, or simply abutting, or one cut so as to over-
lap the other. Of late years the curbs have been made of cast iron. Behind
these a planking of 9 or 10 feet planks is driven down, and if we are
employing the method of spilling, these planks will be made to fit to each
other very carefully. The curbs will be held together by stringing deals or
laths. In this way the pit will be put down from the surface until you reach
such a foundation as leads you to expect that you can base it on a satisfactory
lining of brickwork. At this point the shaft will be widened, a little pit
being sunk below for the accumulation of water during the process. The
cutting will be done with pick, or hammer, or gad, or by any method except
blasting, so as not to injure the ground. Then a curb is put in, now usually
of cast iron, and above this will be built the walling.. The precautions
to be taken are that the bed should be very smooth and perfect, and that
between the segments of cast iron there should be thin sheets of deal, so as
to give a perfect joint when present together. . As the walling is built
up, all hollows are carefully filled, so that nothing can fall suddenly on
•
CHAP. II.]
SINKING OF SHAFTS IN DERBYSHIRE.
577
the workmen. In this manner one of the segments will be completed-then
another segment will be proceeded with, in like manner below the first; and
when the second casing of brickwork has been built up, the bracket of ground
between it and the first will gradually be removed."
All this applies especially to the very superior shafts which are sunk in
collieries. It must be remembered that where one shaft so thoroughly con-
structed is required in a large colliery, a dozen shafts may be, and often
are, sunk in the more solid rocks of a metallic mine. It is, however, greatly
to be desired that those shafts which are used for bringing up the ore, and
which are the roads for entrance to, and exit from the mines, were more
frequently built upon this system.
Mr. Smyth continues: "We have considered the method of securing
shafts till we get down to a sure foundation. In some cases the masonry is
put together on the surface and then lowered. In metallic mines, where
the shafts are inclined, according to the inclination of the vein, this plan
cannot be adopted; consequently where there is much water, it has to be
kept down by pumping. Even where other portions of the shaft are secured
in another manner, as with timber, there will be considerable advantage in
securing the upper portion by means of masonry. Where in old shafts there
was only a small area to be protected, our forefathers took a great deal of
trouble in securing them, and this was by no means thrown away, seeing that
otherwise the shafts would have collapsed at the surface. It is too much the
case now in metalliferous mines that they are not walled up to the top of the
shaft, and, consequently, this part is forced in, giving rise to expenses and
dangers, and leading in some cases to loss of life, and in all causing consider-
able risk. The means of securing against this would be to line up, from a
secure foundation, the sides of the shaft with stone-work. Then, when the
mine is abandoned, the top might be covered up with a few large stones,
and if it were required again the shaft would probably be found intact."
It now remains for us to notice the peculiarities which prevail in some
of the more important districts. In the first place, the system common
in Derbyshire must be examined. The description given by Farey in 1811*
has been but slightly modified since his time. The following, therefore, is
generally borrowed from him, a few notes only having been added to his
very correct description, to adapt it to the modern practice.
It rarely happens in sinking mining shafts that the measures are so
soft, after the corn-soil or day-earth is passed through, as to admit of being
dug, until after the pick has been laboriously applied to loosen the measures,
and more commonly gunpowder is necessary to blast and loosen them, even
where decomposition, or perishing, so quickly follows exposure to the air,
that a lining of stone, brick, or timber is necessary to keep the sides up,
and prevent the shaft from "choaking" or running in; such soft or perishable
strata are called "timbering measures" in many places. Shafts intended to be
timbered, or lined with wood, are made square, or with parallel sides; while
such as are to be ginged, steined, or lined with stone or brick are round or
oval, in some few cases. For shallow shafts, a stowe, turn-beam, or turn-tree,
* "General View of the Agriculture and Minerals of Derbyshire, with Observations on the Means of
their Improvement." By John Farey, sen., Mineral Surveyor.
578
[BOOK III.
PRACTICAL MINING.
which is a rope-roll-with winch-handles for men to work, is erected over the
shaft when dug as deep as men can conveniently throw out the stuff; and
by means of tubs or close corves the water and sinking-stuff is sent up; but
more usually, a horse-gin or horse-engine is erected near the shaft, having a
large drum or rope-barrel, whence the mine-ropes are conducted to pulleys
fixed over the shaft, by which means one barrel, or corve, ascends, while the
other descends.
In sinking shafts in rock or hard measures, it often happens that the sinkers
are obliged to work mid-leg deep in water. In such cases they bore or drill
their blast-hole of a proper depth in the bottom; which done, a signal is
given to the engine-tender (or tenter), above to work the engine briskly, to
lower the water as much as possible. The sinker then throws a lump of
tempered clay, about the size of his head, on the place where the hole is
bored, pressing it firm all round to the rock, and into this clay he sticks a
hollow open cone of plate iron, 15 or 16 inches high, with the small end
downwards, over the blast-hole. The water is then laded out of this cone or
funnel, and then the clay is taken from within it and out of the bore-hole,
from which the water is also extracted, and the sides of it somewhat dried,
by introducing rolls of soft paper or oakum, and in case water springs in at
the bottom of the hole it is filled again with stiffly-tempered clay, which is
driven very hard into the hole by a plug of wood which fits it, after which
the clay is scraped out again and the hole dried; it is then charged with
gunpowder in a tallow-papered cartridge, which is rammed, stopped, and
primed by a wire, in the usual manner, and its fuse fired, when the sinker
instantly slings himself to the drawing-rope, and on a signal made is drawn
to the top, if the shot be set in a rock, but if in bind, though a larger charge
of powder is used, he is usually drawn only 10 or 15 yards up the shaft, to
wait the explosion.
Ginging and Timbering of Shafts in Derbyshire.-During the process of
sinking, which has been treated above, the sinkers examine carefully
the sides and bottom of their shaft, to ascertain such beds of hard and com-
pact rock, coal, &c., as will stand permanently without lining, and in these
parts the shaft is carefully made of its proper size, and no larger; while
between such beds, it is cut out as much wider all round as to receive the
stones, bricks, or timbers and planks which are necessary to support it like
the lining of a common well.
In soft or timbering measures the sinking is carried down, as far as is
judged safe, of a larger size than the intended shaft, when a curb, or flat ring
of sound oak or elm, is laid on the bottom, on which the stones or bricks are
built to the top; the sinking is then begun within this curb and continued
down for 2 feet or more of that size, after which it is enlarged or bellied out
to the size necessary to receive the ginging, and thus is continued down as
far as is judged safe, when a new curb is laid, and the steining worked up to
the contracted part, which is then cut out on the opposite sides of the shaft,
so as to build up a pier or part of the wall in each, and firmly underpin it
to the curb above. Other parts are then cut out between these, and the wall-
ing or ginging built up, and so on, until the whole of the stuff left to support
the curb and walls above is removed and the ginging completed.
CHAP. II.]
COST OF LEVELS IN PLATE BEDS.
579
In some cases, where water comes into a shaft, from a particular measure
between or above such as are compact and water-tight, a process called
stopping-out,” “beating-out," or "framing-out" is resorted to for prevent-
ing such water from making its way into that shaft. In ginging shafts this is
effected by making the shaft about 2 feet wider than necessary, building the
wall, or ginging, very firm in mortar made of water-lime, like that from
Barrow-on-Soar,* and ramming the space behind with well-tempered clay;
carefully joining such clay to the water-tight measures below and above
those where water is to be stopped-out of or confined in the measures.
In order to avoid the inconvenience of wet shafts, and the damage they
occasion to the mine ropes, &c., spiral channels are often constructed behind
the ginging, called "garlands," which intercept the water oozing from the
measures, and convey it down, either to the bottom of the shaft, or to some
level, or pump-cistern, whence it can be discharged, or pumped up, without
descending to the bottom of the mine. When water is stopped-out of
mine-shafts, or gates, by means of close wooden trunks or linings, as at
Boggard mine, in Wirksworth, and other places, it is said to be framed-out.
Westgarth Forstert is especially earnest in recommending that plans
should be carefully kept of every portion of the works in the mine, but he is
loose in his description of the workings himself. A few facts are, however,
of interest. He says, for example:-
"As mines generally occur in hilly, or mountainous grounds, and may be
drained by means of levels, or adits, driven from the bottom of the hills, or
mountains, it will be right to commence with the expense of driving those
levels, per fathom, in the different beds which have been productive of
metallic ores, and also in plate beds, or indurated argillaceous earths, in
which ores have been seldom found to occur; but these last are better to
drive in, than other beds of harder ore stone, therefore where there is a
situation for draining the mines by levels, and a plate bed can be found to
answer the purpose, it is preferable to any other.
"The measures generally used in Alston Moor for horse levels, are from
3 feet 4 inches to 4 feet wide, and 6 feet high, or thereabouts; and such levels
may be driven at first, in a plate bed, to the length of 20 or 30 fathoms for from
£1 to £1 Ios. per fathom, exclusive of the charge for arching, wooding, and rail-
ing. But as the level proceeds further into the hill the incumbent weight
becomes greater, the plate, shale, or schist more indurated, and the distance.
longer to remove the rubbish, and it may be necessary to increase the price
per fathom to £3 or £4 or upwards. [It must not be forgotten that these
were the prices prevailing more than sixty years since, and that consequently
they have been increased in proportion to the general advance of the value
of money.]
"It sometimes happens that a plate bed cannot be found to answer the
intended purpose, when it may be necessary to drive in Limestone-hard
Sandstone, or hazle. . . . . Such levels will require from £4 to £5, £6, or
* A blue lias clay found at Barrow-on-Soar and a few other places is considered superior to any other
for sluices, locks, and piers, and other waterworks, on account of its property of setting immediately, even
under sea-water, and continuing to harden.
↑ "Treatise on a Section of the Strata from Newcastle-upon-Tyne to the Mountain of Cross Fell, in
Cumberland." By Westgarth Forster. 1821.
P P
580
[BOOK III.
PRACTICAL MINING.
£8 per fathom, exclusive of placing the rails, &c., as before. When these
levels have proceeded to the length of 50 or 60 fathoms, the miners gene-
rally require a circulation of fresh air, and for this purpose either a bore- ·
hole may be put down, or a shaft sunk, so as to communicate with the farthest
part of their workings. If there is a small stream of water at the surface it
may be allowed to fall into a cistern, or tub, at the bottom of the bore-hole or
shaft, and it has the effect of carrying down along with it a current of air.
This contrivance is called by the miners a water blast. In some machines of
this kind the constructors seem to have been of opinion that a great height
was required in the water-fall; but numerous experiments have shown that
an excess in height can never make up for a deficiency in the quantity of
water.
•
"The measures used for whimsey, or horse-engine shafts, are generally
about 4 feet 6 inches long by 3 feet broad. Whimsey shafts may be sunk
to the depth of 10 or 15 fathoms, at from about £2 10s. to £3 or £4 per
fathom, and after that from £5, £6, or £8 per fathom, exclusive of the charge
for timber, walling, &c. &c."
Having described, as far as it appears necessary to do so, the construction
of shafts, and securing them by lining, either with timber or with stone, we
have to proceed to the consideration of the excavation of the passages, which
may be driven through the ordinary non-productive rock, for the purpose
of reaching the lodes, or, upon the course of the lode itself. In the first case,
a considerable quantity of stone of little value is broken out; and in the
second, the material broken out of the lode may be of real value. The latter,
of course, is speedily sent to the surface, and there prepared for sale; and in
the former the débris has to be deposited somewhere in the mine, where it
may possibly serve some useful purpose.
In many of the metalliferous rocks, the ground is sufficiently firm to sup-
port itself, but it often occurs that there are defective pieces which demand
support. Hence, even in metallic mines, it often becomes necessary to
secure the sides of a level. In many of the metalliferous mines the rubble-
stone, which has been broken out in excavating, serves for the purpose of
securing the sides. If the rock is Granite or Elvan, or Trap, the pieces can
be readily squared. If a schistose character prevails the pieces can be laid
flat, and carefully built upon each other. It is important, whichever plan
of walling is adopted, if the stones are not used dry, to cement them, in which
case it is always the most prudent course to use hydraulic mortar made thick
and spread rather sparingly, as a continuous film, between the beds of the
successive courses, so that the spaces between the stones of the same course
should be completely filled when the stones are pressed closely together.
It is frequently thought expedient to use timbering for securing the sides
as being the more economical. Legs are, in this case, driven into the ground,
the bottom of the level being made wider than the top, or "back," and the
"cap" is fixed securely at each side to the top of the legs, and cross pieces
secure the legs at the bottom; then lathes are driven in and carefully secured,
Fig. 153.
When a gallery is pierced in ground of medium consistency, the miner is
generally able to penetrate some distance without any support, and can
CHAP. II.]
THE TIMBERING OF LEVELS.
581
therefore build up the timber, as he advances. Supposing the four faces of
the gallery, the roof, the wall, and the lateral partitions need support, it is
necessary to establish, what is called, a complete timbering composed of frames
and laths. Each complete frame is formed of four pieces, a cap-sill or cornice
placed across the gallery, two posts, generally a little inclined, to diminish
the bearing of the cap-sill, and a sole-timber placed on the soil, and serving
Fig. 153.
Fig. 154.
as a base to the posts, Fig. 154. Galleries driven into soft ground must be
built up, and then the timbering is only used to facilitate the construction of
masonry, strong enough to resist the pressure of the soil and check the infiltra-
tion of water. In such cases the arrangement of the timber is very simple, and
generally entrusted to the miners themselves. The timbering consists prin-
cipally of props placed perpendicularly from the roof to the wall, and wedged
into their places by means of boards. When the gallery is a high one the
props are placed according to the plan of the bed or vein, and sustained in
that position by strong oaken boards, fitted into each other by notches, or
so pressing against each other, that the greater the weight resting on the
prop the closer becomes the pressure.
A sufficiently correct idea of a well-timbered gallery, and of the miners
working-one in bringing down the rock from the end-and the other in
loading a small truck placed upon a tramway, with the ore or rock, as the
case may be, is shown in Fig. 155.
་་·་
Fig. 155.
For the conveyance of the stuff broken out, in all rich mines, subterranean
tramways are laid down. In Wales, however, in general, no other means
are employed than a wheel-barrow run along the uneven floor of the rock.
PP 2
582
[BOOK III.
PRACTICAL MINING.
Especial attention should be given, by the mine agent or engineer, to the
timbering of a gallery, and if time is not of importance, it should be done in
a fairly substantial manner. In some cases the necessity of placing supports
arises suddenly. Then, of course, the miner must exert his thinking powers
in determining how best to meet his difficulty. As soon as possible, how-
ever, the temporary supports should be removed, and good timber frames
should be placed against the sides of the levels. The timbering should
always be substantial, and be kept in good repair; at all times, if there
is any tendency detected in the sides to thrust or press unequally on the
timbering, the defective part should be immediately secured. It frequently
happens, where the tendency of the roof to fall is considerable, that the rock
broken out of the level can be built sufficiently solid to resist a general
subsidence. The usual, and perhaps the most effective, system is to build
a good wall, especially where Slate stones are broken out; and unless they
can be placed securely flat, as in their bedway, and spread judiciously,
a little mortar must be used. The cementing of the Slate slabs requires
the experience of a good mason. Then all spaces behind the wall should
be filled in with the refuse (gob-stowing), making it as solid as possible. In
many mines the infiltration of water holding iron in solution acts as a
cementing agent, and eventually the mass becomes very nearly solid.
These pack-walls, if judiciously built, will furnish a very secure support to
any roof.
The foot-piece is obtained by cutting a large prop into
tudinally, and the flat face is laid on the floor of the level.
two pieces longi-
The back of the
sole is cut so as to
receive the side props,
their larger end being
usually placed upper-
most. They are always
slightly inclined; the
cap is adjusted so as
to rest securely upon
these props, and thus
the frame forms a very
firm trapezoid. After
being fixed, the frame
is tightened by driving
in short pieces of wood
between it and the
rock, and above the
collar, or cross-piece.
In high galleries it is
sometimes advantage-
ous to arrange the
spreaders so that they may form an air course above, or to floor the level so
as to secure a water-course, or a good travelling road.
Fig. 156.-Props in Level.
When one side of the level is weak and the other is firm, one side-prop
and a cap-piece are generally sufficient, Fig. 156 The end of the cap-piece is
CHAP. II.]
WALLING END OF A GALLERY.
583
placed in a hole cut in the solid side, while the other end is supported by a
prop. When both sides of the level are firm, a simple stemple may be used
for supporting the roof-then its ends will rest in holes (hitches), cut in each
side next the roof.
After the lode has been worked away, support is often required, and
frequently the space above the level is filled in with deads (attle). The weight
of the filling up is then carried by stull-pieces, which are covered with boards
(stull-covering), or poles (lagging), to prevent the stuff from running through.
These pieces are placed at right angles to the plane of the lode, and rest in
hitches, the depths of which depend upon the solidity of the walls. The hole
cut in the rock must be of such a shape as to allow the spreaders to be easily
adjusted, and then it must be carefully secured by a wedge well driven in, by
which means it will be rendered less liable to be bent under the weight
which it will have to support.
The character of ground necessarily varies considerably, and occasionally
the miner passes from very hard and coherent rock to soft stone, and some-
times even to running sand full of water. This, however, is rare in metallic
mines, although not unusual in coal mines. The adjustment under either
of these conditions is, to arrange a set of lathes behind the poles and to
drive them tightly, so as to fit together firmly, and thus offer the greatest
resistance to the pressure.
Sometimes it is necessary to employ walling or masonry in a level, which
is of course but slightly different from the walling of a shaft. Callon,* in
his "Lectures on Mining," says, very correctly: "If the question be closely
examined, it will be found that walling has not been employed as often as it
might have been, with advantage. In order, however, that this remark may
be correct, it must be understood to apply only to the case in which the
walling can be made so substantial at first, that it will last for the whole
length of time during which the gallery is
•
to be kept open, without requiring notable
repairs.
On the whole, it may be said
that the practice of walling ought to become
more general as the mines become deeper
and more extensive, and as the works below
ground have to be kept open for longer
periods . . . . but it does not seem pro-
bable that walling can altogether supplant
timbering in the ordinary workings of a
mine."
Fig. 157.-Walling end of Gallery.
Fig. 157 represents a gallery in which it
has been necessary to employ masonry. In
building a vault of this kind the miner has
to be very careful in the choice of materials,
whether quarry stone or brick be used.
piercing of a walled gallery is conducted in the same manner as a timber
one; it is executed in sections, the excavations first being sustained by
The
** “Lectures on Mining," delivered at the School of Mines, Paris, by J. Callon, Inspector-General
of Mines. Translated by C. Le Neve Foster and W. Galloway.
584
[BOOK III.
PRACTICAL MINING.
provisional timbering. When this is removed from the sides to make way
for masonry, the removal must not only be complete, but all spaces left vacant
by the removal should be carefully packed with (attle) rubbish, and in some
cases it is advisable to use concrete.
In masonry with parallel joints, the joints should be perpendicular to the
pressure; and, if arches are necessary, the chord of the arch should be at right
angles to the pressure, and the imposts as solid as possible, the thickness
increasing as the arch becomes flatter. The mass of masonry erected should
be made strong by being tied well together, using binders where neces-
sary, for which purpose old timber may be advantageously employed, cut
so that the length of each piece is equal to the thickness of the masonry.
If the roof requires supporting, caps may be used, their ends reposing in the
side walls or on pieces of old timber placed horizontally, so as to distribute
the pressure over a large space.
In the lead-mining districts of Wales, of Derbyshire, &c., the facilities for
driving an adit level, or a water level, often supersedes the necessity of
sinking shafts. The lead ore is generally sent out through the adit, and, for
the conveyance of ore and stone, subterranean tramways are laid down, but
frequently a wheel-barrow only is employed, and this is driven over the
uneven rock floors of the level. Mr. W. W. Smyth has the following
remarks on mining in Cardiganshire*: "Under favourable circumstances,
shafts are sunk on the course of the lode, at convenient distances, connected
by galleries or levels, at every 10 fathoms in depth, besides which short
underground shafts or 'winzes' communicate here and there, from one level
to another, and the orey mass is thus subdivided into quadrangular portions
of convenient dimensions. The valuable part is 'broken' by 'overhand
stopeing,' or a series of reversed steps, where the 'attle' or rubbish is
thrown underfoot, whilst the miners thus rise from a lower to a higher
'level,' extracting as they proceed all the 'orey ground.' It is manifest,
however, that by this method a certain degree of expensive preparation
must precede the profitable extraction of the ore; and we find that in too
many cases, either from want of sufficient means or knowledge, these pre-
paratory operations are neglected, the seizure of the orey points made the
first object, and a mine which might in better hands prove a lasting source
of profit, is for a while forced to yield more or less of its treasure, at greater
comparative expense, and is eventually crippled, abandoned, and left with
a bad name to deter future speculators, or at all events in such a state as to
require on their part a large outlay to restore it to a more favourable
condition."
In Alston Moor, in peculiar situations, the miner is compelled to sink a
shaft, but in most cases, owing to the hilly nature of the country, an adit or
level is cut, which in this district signifies a passage cut in the solid rock
large enough for men or horses, as the case may be, to pass into the
mine workings. The usual dimensions of a level in Alston Moor is 3 feet
in the bottom, gradually widening to the middle, and then being arched
to the top, which is from 6 to 7 feet high. A horse-level seldom departs
*On the Mining Districts of Cardiganshire and Montgomeryshire." By Warington W. Smyth,
M.A. ("Memoirs of the Geological Survey of Great Britain," vol. ii. part 2, p. 668.)
CHAP. II.]
PARTNERSHIP BARGAINS IN ALSTON.
585
from a very gentle rise, just sufficient to allow water to run along it. On
the floor of such levels, wood or iron rails are laid for the purpose of
facilitating the passage of the laden waggons. From these levels the vein
is reached by a rise-a shaft worked upwards from one side of the level to
the vein. At the bottom there is usually a short flat space left, 3 feet above
the sole, or floor, of the level. The rises are cut at 15 or 20 fathoms
apart, and the working is carried on alternately, this being convenient
for the removal of the mineral or other matter broken down.
The partnership bargains, as they are called in Alston Moor, of the work-
ing miners with the adventurers are always regulated by the prospects of
the vein. The parties undertaking any mine work are bound to observe
the condition of commencing the work within a month from the date of
signing the agreement. The work is to be regularly continued from day to
day until the end of the term, and at least two workmen are to be con-
tinuously employed. One-fifth part of any ore raised is to be paid, as duty
or rent, to the Greenwich Hospital.
The bargain includes labour in the mine-gunpowder or other necessary
explosives-candles or lamps, and the charge for the conveyance of the ore
or stone to day, i.e. outside the mine-and also the dressing (preparing) the ore
for smelting. The price of working is always fixed by the bing of 8 cwts.
Where the veins are thin, or where the ore is mixed with veinstone, a great
quantity of valueless stone has to be removed for the purpose of having drift
room to allow room for working the vein. All these circumstances have to
be estimated in the cost of production. The average price in Alston for
working lead ore is generally 30s. per bing. Four bings of ore are con-
sidered to produce a fother (sometimes fodder) of lead; for this the mine
owners raise five bings, one being paid as royalty, or rent, to Greenwich
Hospital. The late Mr. John Taylor stated that, judging of mining on a
large scale, as much is paid for dead work-that is, for breaking out unprofit-
able rock—as is paid for raising the ore.
The miners work generally by rises 8 or 10 fathoms high, and have
stemples or pieces of wood placed at two opposite sides 4 or 5 feet above
each other. Workings continued downwards under the first drift are called
stoups, and in them the vein is worked to the bottom of the drift. When the
vein is productive below the horse-level, a sump is sunk to the required depth,
which, if the ground is soft, is walled, but if the ground is hard it is left rugged
and irregular. From the sump a drift is made, and the vein, if rich, is worked
by headings and stoups, the work being drawn up the sump by a hand-
whimsey. In a flat vein the workings frequently run to a great extent, the
roof being supported by pieces of timber of sufficient strength.
In Alston Moor, after a mine is opened and appears to be productive, the
miners take a certain piece of ground commonly called a length, in which
they propose to raise ore for a certain time at so much a bing,* according
to the richness of the mine or working. A length of ground is commonly
either 12, 15, or 20 fathoms, and the price of procuring the ore depends
much upon the hardness, the expense of drawing the stone or ore out of the
mine, and the probable quantity of metal that can be raised.
* A bing is equal to eight hundredweight.
586
[BOOK III.
PRACTICAL MINING.
with
After working a length in a productive mine, the space is kept open
deads, leaving only a rise, from which another drift, called a heading, is made;
the same operation being repeated until the top of the stratum, or the
uppermost part of the vein, is reached.
The expense of drawing the ore or stone out of the mine when horses
are employed is considerable, and depends entirely upon the length of the
level or adit, and depth of the mine. In Alston Moor it is usually drawn out
at so much per shift, and at some mines a shift consists of eight waggons, at
others six only.
A miner's waggon, calculated for an eight-waggon shift, will contain thirty
kibbles, and the capacity of each kibble is fourteen quarts or thereabouts.
Waggons calculated for six-waggon shifts contain forty kibbles, making the
shifts in both cases equal. The expense of drawing a shift in horse-levels
varies from 3s. 6d. to 8s., including the filling, driving, and emptying the
waggons, there being no allowance made for the difference of weight between
the ore and the stone.
The dressing of the Lead ore is a division of the practical department,
which receives considerable attention in Alston Moor. The separation of
the ore from the Limestone, in which it is usually found, is not difficult, but
the work required to bring up the value of the poor ores, and the smaller
portion produced in working, is often so considerable, as to be remunerative
only when great care is given to the work.
We presume that it will not be unacceptable to the reader to insert the
following table, showing the value of lodes of different dimensions. Sup-
posing a cubic foot of pure galena weighs on a medium 7,000 ozs. avoirdupois
weight, a bing will then be equal to 14,336 ozs. We shall, according to the
above, have as under, viz. :-
Inch wide.
123456
I2
36
•
Cubic feet.
3
76
Feet high.
6
Feet long.
6
6
6
6
6
6
6
•
6
•
6
6
6
6
•
6
6
6
•
92 5∞
I 2
15
18
· •
•
:::
Bing.
I
•
Cwts. qrs. lbs. ozs.
2 24
www
3736 NO 45
12457∞ 7
36
108
•
17
52
•
2
6
I 21
0 17
3 14
2 ΙΟ
I 7
O
8
8
2 14 O
5 3 14
O
The Kind-Chaudron System of Shaft-Sinking.-Before we quit the subject
of the mechanical operations necessary for the opening out of the mine, it
appears necessary to give some account of this method of shaft-sinking in
water-bearing strata. It must be admitted this system applies more generally
and directly to the sinking of shafts in the Coal Measures; but there are cases
in which the metalliferous miner will be glad of information on this system.
By the process worked out and improved by M. J. Chaudron, a Belgian
mining engineer, no pumping machinery is used, and the water of the strata
is not meddled with. The whole operation of sinking and tubbing is, with
the help of certain tools and apparatus, done from the surface; not a man
descends until the shaft is quite finished, securely tubbed, and absolutely
dry. The water remains in the hole all the while, and, so far from being a hin-
drance or obstacle, is absolutely necessary for the working of the Chaudron
system, as will clearly appear from the description. Moreover, the walls
CHAP. II.]
THE KIND-CHAUDRON SYSTEM.
587
or sides of the shaft are supported to a considerable extent by the water
remaining inside, whilst under the old system the continued and increased
flow of water, induced by the process of pumping itself, loosens the sides of
the shaft, thus causing them to tumble in. This system, in fact, is not
recommended except when much water is expected. In all other cases the
ordinary ways of proceeding, if not quite so certain and efficacious in their
results, may be cheaper.
1. Preparatory Work.—This consists in the erection of the buildings and
sheds which may be found necessary, according to the special circumstances
of each case; in the construction of the required machinery, and the prepara-
tion of the boring tools and others. The buildings should be arranged in such
a way as not to interfere with the ulterior erection of the permanent ones, or
with the winding machinery, &c., necessary for working the shaft when finished.
A wooden building, with strong timber frames, will in most cases be suffi-
cient. The power necessary is an ordinary winding engine, strong enough
to lift the tools, and to withdraw the spoon or ladle used for extracting the
débris. For a pit of large diameter, this machine may have a cylinder of
20-inch diameter and 40-inch stroke; the beating cylinder being a simple
steam-cylinder open below, and of 3 or 4 feet maximum stroke. It contains
a piston of about 30 to 36 inch diameter, the rod of which, passing through
top cover of cylinder, is connected to one end of a strong braced timber
beam. This beam is supported near the middle, and to its other end the
tools for boring, &c., are attached. Steam being admitted by the attendant
into the top of the cylinder, the boring tool attached to the other end of beat-
ing beam is lifted up, and the exhaust being afterwards opened suddenly,
the tool comes down with a force in proportion to its great weight, crushing,
at each blow, part of the bottom of the shaft. The beating cylinder is always
and entirely worked by hand. The stroke of its piston is limited by a strong
wrought-iron loop attached to the end of a braced timber beam, securely fixed
in the foundation of engine-house. Between this loop and the beating beam an
india-rubber and leather packing is introduced to deaden the blows and noise.
2. Boring or Sinking the Shaft. The process employed during this part
of the work is, generally speaking, that which, a good many years ago, was
first successfully and repeatedly made use of in the case of borings of large
diameter by Mr. Kind, the well-known German engineer and sinker of
artesian wells. Four men only are required for this part of the work. The
first tool used is a small trépan, or drill, consisting-say, in the case of a pit
of about 15 feet diameter-of a heavy solid forging of 7 or 8 tons' weight,
or thereabouts, according to circumstances, and measures across its lowest
and widest part 6 to 7 feet, this being the diameter which it is intended to
give to the first boring. This diameter is afterwards enlarged by a greater
trépan, which has a weight of, in some cases, up to about 20 tons.
The
cutting part of the tool must, of course, be greater than the ultimate clear
diameter of the pit.
The trépans on their lowest surface are armed with steel chisels or teeth,
firmly fixed by keys in carefully-bored holes. Such a tooth weighs up to about
cwt. The outside teeth have a special shape protruding somewhat over the
solid body of the tool.
3
588
[BOOK III.
PRACTICAL MINING.
:
By means of connecting-rods the trépan is then attached to the beating
beam. Everything is now ready for the work of drilling. The attendant, at
the beating cylinder, admits steam over the piston, thus slowly lifting the
trépan through a maximum height corresponding to the stroke of the beating
cylinder. On allowing the steam to escape suddenly, the tool comes down
with great force, doing its work of crushing the bottom. Three men standing
on a platform take hold of a lever, before each new stroke, and turn the
trépan slightly round its axis, so as to always work on a new line of the sur-
face of bottom of pit. The length of the connections between beating beam
and trépan must, of course, be gradually increased as the work proceeds.
The first bore-hole made by the small trépan should always be kept ahead of
the larger one by, say, at least 18 to 20 feet. All débris detached by the
large trépan will thus fall into the smaller hole, and can be withdrawn there-
from by a special tool called "spoon," or "ladle," which is a wrought-iron
riveted cylinder suspended in a wrought-iron fork, and of a somewhat less
diameter than the first boring, so as to allow of its being lowered into it
without difficulty. The bottom consists of two flaps which open upwards
when the tool is lowered to the bottom of bore-hole and worked a few times
up and down through a short distance by the aid of the winding-engine.
They thus allow the débris, previously formed by the working of the trépan,
to enter and fill the spoon. On beginning to wind up these flaps close
immediately, and the contents can be safely landed on the surface. The
average progress of sinking by these means varies in ordinary strata between
2 and 4 feet per day.
3. Tubbing. After having bored the shaft to the desired depth and
diameter, the next most important operation is the putting in of the tubbing.
M. Chaudron's tubbing consists of strong cast-iron entire rings or cylinders
having inside flanges at top and bottom, and a parallel strengthening rib in
the middle of their height. The total weight of tubbing for a shaft may
easily go up to, or exceed, 1,000 tons, and the very simple and ingenious
invention of M. Chaudron, for the lowering of this enormous weight, consists
in attaching a temporary bottom, in a water-tight manner, to a special inside
flange of the lowest ring but one. By this means the ring in question is
immediately changed into a vessel, and able to float on the surface of the
water in the shaft. Nothing is now easier than to add ring after ring, taking
always the utmost care to render all joints absolutely water-tight. Special
arrangements have, however, to be made to secure the sinking down of the
tubbing, which would otherwise remain floating. This is done by erecting,
and gradually increasing in length, a column of pipes fixed to a hole in the
temporary bottom. The pit water, finding its level in this equilibrium pipe,
can then be allowed to enter by cocks provided for this purpose, and charge
the tubbing to any degree required; care must only be taken not to allow
one of these cocks to remain open, and sink under the surface of the water
level.
To cut off all communication between the inside of the tubbing and the
overlying water-bearing strata, the shaft should have been sunk to such
a depth as to pierce the water-bearing strata by some little distance, and to
enter into solid and unbroken ground. On this latter the tubbing is allowed
CHAP. II.]
TRIGER'S SYSTEM OF SINKING SHAFTS.
589
to come to rest, and in order to get a water-tight joint between the outside.
and the lowest part of the tubbing, and the surrounding rock, M. Chaudron
conceived the idea of giving to the lowest ring the construction of a gigantic
stuffing-box. This consists of an outer ring, having at its lower end an
outside flange, inside which, and loosely suspended by bolts, is a ring of less
diameter, likewise provided at its lower end with an external flange. These
two external flanges confine a space which, before the introduction of the
stuffing-box into the pit, is filled carefully with moss or a similar material,
retained by thin thread or wire-netting. As soon as the tubbing touches its
ultimate resting-place at the bottom of the pit, the whole of its enormous
weight is gradually allowed to compress the moss in the stuffing-box and
thereby immediately, and for once and all, cuts off the water from the upper
strata.
4. Cementing.-In order to still further secure the permanent tightness of
the tubbing, and in order to support it completely and all round, the space
remaining between its outside and the wall of bore-hole should now be filled
up with concrete or mortar. This operation is executed with the help of a
special tool.
5. Withdrawing the Temporary Bottom.—In order to do this it is necessary
to extract the water inside the tubbing. This should, however, not be
attempted until the cement outside has had full time to settle and harden. It
is easily and quickly done by a bucket, and by the help of the engine
previously used for the sinking. The next operation is the removal of the
equilibrium column, and of the temporary bottom, to which it was attached.
The joint made by the moss box can then, if desirable, be supported and
secured by further precautionary work, such as the introduction of a wedging
crib and masonry. After this the application of Chaudron's system is at an
end, and sinking and mining operations are begun in the ordinary manner.
One other ingenious method of sinking shafts must be mentioned.
M. Triger, engineer in the Department of Maine and Loire, had the idea
of making a well in the very bed of the Loire by means of compressed air.
A cylinder of thin iron, which served as a cutting-machine, was sunk into the
alluvium; it was separated into three compartments by horizontal partitions.
The upper compartment remained always open, the lower compartment
was the workshop, and between them was the middle one, which served as a
chamber of equilibrum, designed to be put in communication with either the
compartment above or the one below. The things being so disposed, they
forced into the bottom compartment air compressed by a vapour-machine
without intermission. This air drove the water up a tube, of which the
lower part was buried in the bottom of the excavation, and of which the
upper part was raised above the cylinder. The workmen were then able to
penetrate the first apartment and open the second, which was afterwards
hermetically closed, and in which the air of ordinary pressure was put in
communication with the compressed air in the third. Having arrived in the
third compartment they excavate the sands, and cause the machine to
descend. As they accumulate the sands excavated in the middle compart-
ment, they have only to remove them by shutting the communication with
the bottom and opening that of the top. A pressure sufficient to balance the
590
[BOOK III.
PRACTICAL MINING.
exterior waters is maintained during the work, without sensibly incom-
moding the workmen. This ingenious proceeding has received numerous
applications. It is evident that wells dug in the water-saturated soils must
immediately be cased, that is to say, covered with a casing of wood or metal,
solid and impermeable, which is able to resist the infiltration and pressure
of the waters.
A plan similar to this was employed by Sir Isambard Brunel in the con-
struction of one of the piers, in the bed of the river Tamar, for the Royal
Albert Bridge, at Saltash.
Drawing Stuff.—When the mine is in its earlier stages of exploration-or
rather of sinking-the stuff is drawn by means of the simple windlass, which
is turned by either one or two men, and the ore is brought to the surface in
the ordinary iron kibble, or sometimes, in tubs. The precautions necessary
in this case are attention to the strength of the ropes and the good con-
dition of the tackle. In many cases it is necessary that even those small
shafts should be carefully timbered, as if the sides of the shaft are loose and
liable to break out, the miners might otherwise suffer from the fall of the
broken masses.
The miners in sinking a preliminary shaft, in most cases, use gun-
powder or some other explosive; and then the hole having been bored
and charged, preparations are rapidly made for ascending, the fuse is lighted,
and the miner drawn with all speed to the surface. The following interesting
circumstance illustrates the perils attendant on work of this character. Two
miners were at work in the bottom of a shallow shaft of this description, in a
mine in the Liskeard district. Everything was prepared for blasting, the
fuse was ignited, and both men jumped into the bucket, holding on by the
rope and calling to the surface to be hauled up. This order was not obeyed,
and presently they discovered that one of the men, who should have been at
the windlass, had left his place, and the one man still at the mouth of the pit
was not strong enough to wind up the two men. No time was to be lost; the
younger man jumped from the bucket, saying, "You go up, comrade; you
have a family, I have none." The man left in the shaft threw himself on the
ground, beside the burning fuse, and seizing a board, placed it upon his body,
and waited in an agony for the explosion to take place. In a little time
it did so, with stunning effect on the prostrate miner, and the fragments
fell in a shower around him. Resting for a minute in suspense, he was
surprised to find he was not hurt, and presently he was drawn rejoicingly
to grass. Many similar examples of heroism amongst the working miners
might be mentioned.
As the shaft increases in depth the "haulage of stuff" is increased, and
the horse-whim is substituted for the windlass.
Horse-whims or gins may be constructed of several different patterns;
the whim represented, Fig. 158, is constructed for heavy work and with a
view to durability.
A is the span beam, with a bearing of 39 feet 16 inches in depth in the
middle and 8 inches thick; B is the horse-arm, 35 feet 8 inches long, con-
sisting of one piece, 12 inches by 7, passed through a mortice in the axle of
the drum D. If this arm is required to stand the strain for a great length of
CHAP. II.]
HAULAGE BY HORSE-WHIM.
591
time it is trussed, and consists of two pieces, each 1 foot 2 inches by 4
inches, notched into and bolted to two opposite sides of the axle D, where
they measure across from outside to outside 2 feet, and then the truss is
gradually narrowed near the ends, where they measure foot 4 inches.
They are blocked apart and bolted together through the blocks between the
centre and the extremities. c is the drum, in this case 9 feet in diameter
and 2 feet 6 inches deep, divided into two parts by a fillet round the middle
of the cylindrical part of the drum to separate the ascending and descending
ropes. The ropes are prevented from working off the drums by horns pro-
jecting around the top and bottom, twelve in number, made of 4 by 4 inch
stuff, and jutting out about 10 inches, the inner side of the projection being
sloped off. D is the drum-shaft, 13 feet 6 inches long and 1 foot 2 inches
square; to this the horse-arm B is securely bolted at 4 feet from its top, and
steadied by stays of 4 by 4 inch scantling from its lower part; to these
stays the driving-boys tied one end of a small cord, which served as a rein
A
ANDEJANJA 10814, ASAULIO DATA TO DA DAN KAN LOA EZAADIOENER
2.4.6......
K
F
É, ALE MOGUI ILAM RUN 23
Fig. 158.-Horse-Whiin.
to the horses, as shown in the engraving. Above the horse-arm, and resting
on it, the drum is secured by the axle passing through it; the frame of the
drum is made square in the centre for that purpose; the lower frame of the
drum is steadied from the axle, at right angles to the horse-arm by stays
similar to those last described. The axle rotates on two spindles of 2-inch
round iron, one end being squared and turned both ways, at right angles, to
secure a firm hold in the column. The top spindle works in a socket formed
by straps bolted to the span-beam, and the bottom spindle works in a bell-
metal cup. The top of the axle has one hoop, 2 inches by inch, driven on
after the spindle is fixed; and the bottom of the axle in like manner has
two hoops. The weight of the top spindle was 28 lbs. ; the bottom spindle,
25 lbs.; the straps for the top spindle, 18 lbs.; the three hoops, 21 lbs.; and
the brass or bell-metal cup, 13 lbs.
1
The horses were harnessed to beams attached to a perpendicular piece,
8 inches by 10 inches, its top forming the end of the truss of the horse-arm,
from which it was pendent; it was also steadied thereto by means of braces.
592
[BOOK III.
PRACTICAL MINING.
The harness-poles were made to revolve on a spindle at the bottom of the
perpendicular piece last named, whereby the horses could be turned round
and proceed in the opposite direction, to reverse the action of the machinery,
which was necessary at every ascent and descent of the ropes-the one
ascending as the other descended, and vice versa. It is, however, more con-
venient to construct the machinery of the gin so that the alternate ascending
and descending action of the ropes can be effected without the necessity of
turning the horses round.
The span-beam A is supported at each end by a triangular frame, the base
of which is 13 feet long, and is steadied with props. E is the pit-frame
placed on each side of the shaft, at a distance of 24 feet 6 inches from the
drum-shaft. This carries the head-gearing or frames, in which are mounted
the pulley-wheels or sheaves, which are of cast iron, 3 feet in diameter, and
weighing I cwt. 3 qrs. The spindle upon which the sheave revolves is of
wrought iron 2 inches diameter, and worked in a bell-metal box or plummer-
block, weighing about 3 lbs. K is a pole, of which there are two, called
jackanapes-poles, because they carry what are technically called the jacka-
napes, G G, whose use is to keep the rope straight in passing from the drum
to the head-gearing, and they have small friction rollers for it to work upon.
These jackanapes are pendulous, and therefore they vibrate or yield as the
ropes move, which is necessary, because the ropes continually change their
levels as they wind round the drum, or vice versa. H shows the trough into
which the kibbles empty themselves when tilted, from which trough the ore is
passed into proper trams, to be transported to the dressing-floors. I shows
the platform, made to run upon flange-wheels worked upon rails, whereby it
can be drawn over the pit-shaft to cover it when necessary, for greater
security in landing the skips full of ore or rubbish, as they are raised to
the surface; the skips are then rolled away on temporary rails and emptied
of their contents. The pit-frame and head-gearing are made of oak, the
frame of the drum of oak, and the covering of elm; the jackanapes-poles
are of larch, the horse-shafts of ash, and the rest of the gin of Dantzic
timber.
For the greater preservation of the ropes, they should be tarred and
payed over with coarse canvas, also tarred where there is an excess of friction.
Some such covering is requisite for economy's sake, as the wear upon some
parts of the rope is considerable. It may be worth remarking that wire ropes
would be applicable with advantage to the purposes under consideration—not
only on account of their greater durability—but to prevent the possibility of
wicked persons cutting or otherwise injuring the ropes, to cause accidents by
their breaking when loaded. Such circumstances have occurred unfor-
tunately, and ropes which have wilfully been cut have broken at a time when
several men in a skip have been suspended by it, whereupon they fell to
the bottom of the shaft and were killed. This, happily, is not of frequent
occurrence. Too great care cannot be exercised where there is a large body
of men congregated together, some of whom may be apt to indulge vindictive
feelings.
At the time of writing these remarks a dreadful accident has happened at
CHAP. II.]
ACCIDENT BY BREAKING OF ROPE.
<
593
Wheal Agar tin mine, near Redruth, in Cornwall. On Wednesday, the
17th of August, 1883, thirteen men were being raised from the 195-fathom level
to the surface. The cage in which they were riding had reached the landing-
place, when one of the men jumped off, and thus saved his life; the wire rope
by which the cage was suspended then suddenly broke, and twelve men were
precipitated to the bottom of the shaft, and consequently lost their lives. The
chief agent stated at the inquest that, as some imperfection had been detected in
the ordinary whim rope, which was generally used for raising the men, it was
changed for the capstan rope. Eight men went to the surface safely imme-
diately after the change of rope. Then "a party" went down, and the next
batch went up. "When they went up there were thirteen in the gig,' ten
on the inside and three on the top. They went up about seven o'clock from
the 195-fathom level. They had reached the surface, and Henry Carbines
jumped out safely." In the drawing rope (that is, the whim rope) they found
one of the strands broken, and the rope was bad for from 20 to 30 fathoms
in length, the strands having coiled back. It would appear that not more than
eight men were, by the regulations in force at Wheal Agar, permitted to
ascend in the cage at the same time, "timbermen, shaftsmen, or pitmen being
excepted, these being allowed to ride on the top, to see that the shaft and
the timbering, &c., was all right." In this case it is evident that the proper
amount of care in examining the rope had not been taken. The evidence of
the engineer-surveyor-in-chief for the Board of Trade-states: "I consider
the breakage was caused through the rope not being sound. Several of the
wires were very much corroded. I can form no opinion as to how long they
may have been in that state, but in the ordinary course of events some con-
siderable time. I must say I think many of the wires which were corroded
would not have been visible to a mere external examination. In addition to
the rope being fractured, owing to corrosion, it was injured in being worked
at a strain of 20 tons. If the rope were a good one I should work it up to a
strain of 5 or 6 tons; but I would not work it at such a strain in raising men.
If there had been a 'kink' in it, that would have made it more liable to
break. I attribute the accident to the corroded state of the rope, coupled with
the fact that it had been used to raise 20 tons."
The Inspector of Mines said he "deprecated the use of grease and oil as
lubricants for such a rope, as they tend to hide defects." This, under ordi-
nary circumstances, is quite correct; but in the case of Wheal Agar these
lubricants-grease or tar-especially over that part of the wire rope which was
attached to the skip, were useful in protecting the wires from the action of the
copper water, into which the loose portion of the rope dipped when it was at
the bottom of the mine. The result of the coroner's inquest was a verdict
of "Accidental death." It is seriously hoped that this sad accident, and
the facts brought out in the inquiry, will lead to such precautions as will
prevent a recurrence of any similar accident.
This will be the proper place to insert some information relative to the
tenacity of wires and of the conditions under which wire ropes may be safely
employed. The following table, showing the circumference of wire ropes,
the weight per fathom, their breaking strength in tons, and working load
594
[BOOK III.
PRACTICAL MINING.
in cwts.,* constructed with great care, cannot fail to be useful as a guide to
the miners :-
Pounds Weight Breaking Strain Working Load
Girth
in Inches.
per Fathom.
in Tons.
in Cwts.
Ha
I
I
PWMFAT
FI+HAMT
1 2 2 2 2 3 333444
-N-A-A-A
I
1 1 2 3
36 7∞
235
6
9
15
7
21
9
27
II
33
13
39
7호
​15
45
17
51
3 ½
IO
20
60
I2
24
72
14
28
84
15
30
90
44
18
ཆབ་
32
96
36
108
The following table again shows the sizes, weights, and strength of flat
wire ropes and of equivalent flat hempen ropest:-
Size in
Inches.
4 X I
4× I
5 × 1
ΧΙ
6
X
HEMP.
WIRE.
Lbs. Weight
per Fathom.
Size in
Inches.
Lbs. Weight
per Fathom.
Breaking
Strain in
Tons.
Working
Load in
Cwts.
161/1
20
24
26
28
2 2 2
36
4
812 × 2
40
X 2
45
45
4호
​XX
XXXX
9
16
36
ΙΟ
18
40
2 580 25
1 2 2 2
12}}
22층
​50
15
18
20
27
60
32
36
2231/
25
صرات
40
90
45
100
2828
72
80
Iron wire, as a rule, has been employed in the manufacture of ropes; steel
wire is now preferred, and until recently the wires were subjected to a
considerable amount of twist in the construction of the rope. This torsion
necessarily lessened the tensile strength, the strain not being always in the
direction of the length of the wire. According to the amount of twisting, so
would necessarily be the liability to fracture, across the length. The wires
should, in the construction of either a round or a flat rope, be laid carefully
together, and subjected to no more twist than absolutely necessary for firmly
securing the strands. It will be obvious, after these remarks, that it is a
matter of equal importance, to wind a wire rope on the largest drum which
can be conveniently used. When first wire ropes were introduced in our
mines, they were placed on the same drums which had been employed
* "Records of Mining and Metallurgy." By Phillips and Darlington. See also “De l'Extraction
dans les Mines du Cornwall," par M. L. Moissenet.
† Mr. Stephen Eddy, of Grassington, states that the difference between a wire and hemp rope,
working under similar conditions, is as 5 to 3 in favour of the former. (Royal Cornwall Polytechnic
Society's Report for 1856.)
CHAP. II.]
PROTECTION IN MINE SHAFTS.
595
for hemp ropes. The consequence was, that it was not unusual to find
the wire rope upon the drum presenting the bristling points of broken
wires.
In connection with winding machinery, much has been said of the advi-
sability of using safety-catches, by means of which, in the event of the
fracture of the rope, the load, whatever it might be, should be prevented from
falling. Safety-catches have been introduced of several descriptions, the
principle being nearly the same in all. When the rope, whether of hemp or
wire, breaks, arms which were held free so long as the weight was suspended
from them, fly out, and catch the guides placed at the sides of the shaft.
These have been used with some advantage in many of our collieries.
They have, however, this objection: safety-catches being introduced, the
condition of the ropes appears often to have been neglected, and they have
been trusted to run beyond the usual period allowed.
Another objection to the use of safety apparatus of any kind, when the
miners are being raised or lowered, is this: while the cage containing the
men is travelling up or down the shaft, if the rope breaks, and the catch is
brought immediately into operation, the momentum of the falling mass being
suddenly checked, the miners receive a blow equal to that of the weight
multiplied by the velocity, which has in many cases resulted in serious con-
sequences. The only safe course is, to reduce the velocity of the falling mass
slowly, and gradually to bring it to a state of rest.
Shafts in metal mines, being used for various purposes, require especial
attention, according to the uses for which they are intended. In many
cases a special shaft is devoted to the pumping arrangements only. For this
purpose the sides of the shaft should be carefully protected, and where the
rock which has been cut through is not thought to be sufficiently firm, good
timbering must be put in, and in many cases a lining of masonry will be
found to be, from its greater durability, the most economical. A ladder-way
is placed in the engine-shaft, to enable the engineer and his men to inspect
the pump work. Other shafts also are employed for pumping, and for raising
the ores. Where this is the case a strong division should be put in it, to protect
the pumps from the falling of masses of ore or stuff from the kibbles or skips.
Many shafts are especially constructed for the use of the miners only in pro-
ceeding to and from the levels in which they labour. We sometimes, how-
ever, find such shafts used for pumping and winding; where this is the case
the divisions should be judiciously designed and carefully constructed.
In all shafts every precaution should be taken to protect the miners from
danger, especially from the fall of stones. A comparatively small stone fall-
ing through a hundred feet or more, acquires by its increased velocity a force
which is sufficient to cause death. The usual practice is to place on one
side, so as to cover a portion of the shaft, a pent-house, beneath which the
miners can retire when kibbles laden with ore or other things are being
raised or lowered. To reduce the risks as much as possible, pieces of wood,
called "striking deals," are sometimes placed under the platforms or support
of the pent-house. These being placed at an angle serve to guide the kibble
in its ascent, so that it passes on safely to, and through, the opening at the top
of the shaft. It is often the practice to divide a shaft for pumping and for
Q Q
596
[BOOK III.
PRACTICAL MINING.
"winding," or "drawing stuff," with a division for a ladder way. Where
this is done the ladders are placed in the middle, and to protect the miners
the side next the division employed for winding should be carefully boarded
through its whole length, but on the side next the pumps it may be left open,
except at intervals, where a slighter separation is advisable.
Kibbles are the buckets in which the ore is placed for the purpose of being
drawn to the surface. These are made at the local foundries of the best plate-
iron, of great strength and resistance, as they are subjected to much rough
usage, and in swinging in the shaft they are liable to severe blows against the
sides of it. Kibbles are still used in small mines, or in shafts which are not of
great depth. The kibble is usually suspended by a chain for a certain length,
which is then attached to either a hempen rope or a wire one. The size of
kibbles varies considerably in different localities, this being often a matter
of caprice, which is of course regulated by the amount of work which has to
be accomplished. Their capacity varies from 1 to 25 cwts.
"Winze Kibbles," used with a windlass and tackle, are usually about
14 inches high and 12 inches diameter, holding about 1 cwt. In Dolcoath
mine, kibbles of a large size are worked in some of the old irregular shafts.
These are often 4 feet high and 3 feet 6 inches wide.
In some mines the amount of "stuff" drawn by waggons and loaded
into the kibbles is very great. At the Lisburn mines, in Cardiganshire,
100,725 kibbles have been drawn to the surface in one year, and at Polberoo
mine, in Cornwall, 174,831 kibbles were hauled in the same period.* The use
of the kibble is gradually passing away, the "skip" travelling in “ guides
being in every way an improvement. A larger weight of ore can be drawn
in the same time, and with a proper amount of care the risk from breaking
or from the falling away of stones is reduced to a minimum. Kibbles are
still used in the shafts of old mines, which are often much inclined and
very irregular. The lower side or the foot-wall of the shaft is generally
lined with timber "bed-plank" to reduce the friction. Under any arrange-
ment, however, the wear on both the kibble and the flooring is very great,
the friction between the two being enormous. Breakages are also very
frequent, the strain on the chains or ropes being excessive, and the shocks
severe. It is the wiser course, as being in the end the most economical,
to straighten the shaft as much as possible, and to put in guides, or shaft
railways. Upon these skips can be run, with considerable advantage as it
respects both economy and safety.
Skips vary greatly in their construction and in their manner of being guided,
so we will take for example those used at Levant mine, St. Just, Fig. 159.
The faces of the skip are united with strong rivets. The long sides are bent
at right angles, and the bottom riveted underneath. The plate of metal which
serves as door is strengthened by two strong bands, and is fastened by a
horizontal bolt and a vertical bar or needle, the eye for the bolt being firmly
riveted to the bottom of the skip. This bolt is placed, or removed, by a blow
from a hammer. Another mode of fastening is by means of a vertical iron
fork the length of the door, which slides into two projections in the bottom
of the skip. This is held firmly by a sort of handle which wedges the top of
* "Records of Mining and Metallurgy." By J. Arthur Phillips and John Darlington.
CHAP. II.]
SKIPS TRAVELLING IN SHAFTS.
597
the fork. The miner who receives the skip at the surface, with two blows of
his pick, can turn the handle and raise the fork.
The handle by which the skip hangs is sometimes arched, but more often
it is bent into right angles, to leave the entrance entirely free when it is
turned over. The axle on which the handle turns is held by a plate of metal
and five rivets. The
skips will generally
contain about 12 cwts.
of stuff, or sometimes
as much as 13 cwts.
The different modes
of guidance adopted for
the skips depend prin-
cipally on the construc-
tion of the shaft. Where
the shaft is vertical, the
skip has no wheels; but
it is kept in position by
bars of wood. When
the shaft is not vertical,
but following the course
of the lode, the skip is
made to run on guides
which form grooves.
The wheels are of cast
iron encircled with
iron of a better kind,
with rims and four
spokes of hammered
iron, and the nave is of
cast iron. They should
be kept as small and
light as possible.
O
•
O
O
O
O
O
а
O
Fig. 159.
Skips of sheet steel might be used with great advantage on account of their
lightness. The extra expense would be compensated by their durability.
If safety-catches were generally employed, and great care and attention paid
to the proper maintenance of the cables, a skip would wear for a long period.
A pair of skips is generally kept in reserve in case of accident, and it is
estimated that each drawing shaft will, as a rule, require sometimes one and
sometimes two pairs in the year.
Skips are now generally raised by means of wire ropes. Unless the
guides or railways are carefully put in the friction is considerable, and it is not
often that a speed of 350 feet a minute is exceeded. In highly-inclined shafts
the skips are always fitted with wheels, but simple guides will suffice, as
already said, when the shaft is vertical and kept in good order.
Generally the skip is filled at the upper end, which, when filled, is closed
by a hinged door. This door is secured by a catch, while it is travelling,
but on arriving at the surface the man who receives it, called a "lander,"
QQ 2
598
[BOOK III.
PRACTICAL MINING.
brings it over the waggon, and, opening the door, allows the ore to slide down
the sloping end.
In mines of a superior class a pair of cages are sometimes used, similar in
many respects to those employed in the collieries. These are arranged to
admit the waggons (Fig. 160), to run in from the "end" or to be brought
close
((
up to the face of the work."
These waggons may be suspended from the rope by iron hooks or bands.
Loops are made one on each side of the waggon, as at AA. These loops receive
the hook of a chain made of §-inch iron attached to the end of the rope by a
shackle. The wheels and axles are attached for the purpose of running the
trucks along the temporary railroad laid from the face of the workings along
the level, and also upon a similar railway above ground, from the top of the
shaft to the dressing-floors.
A
A
A.
2...7
251
Fig. 160.
The dimensions of a pair of such waggons is given in the drawings, but they
vary considerably in this respect. The ring A is adjusted so that if necessary
the waggon can be slung, but when run into cages this is not necessary.
By this arrangement much greater speed is attained, as the waggon is loaded
near the working place of the miner and the load is not disturbed until it
reaches the surface.
12
In the tin and copper mines the drawing of mineral through the shaft
requires much attention. The rate of drawing is constantly varying—
sometimes it is from shallow levels, and sometimes from very deep ones.
In this country the levels go off from the shafts at intervals of 10 or
fathoms, and in many of these levels there may be active workings. In
some mines the accumulation of mineral is large in the levels, in others it
is small. Frequently the mineral is allowed to accumulate in the levels,
impeding the passages of the mine and interfering with the ventilation. It is
not unusual, where the ground is worked by tut work, and it is often con-
venient, to have adjoining the shaft some means of storing the ore. This
space is termed "a plat," the variety ordinarily used being called "a tip-plat."
Where the level opens into the shaft, for a distance of 2 or 3 fathoms back
from the shaft, a stope is generally taken about the same height as the level,
and the rails used will be continued over this by a framework of timber.
This is useful, as the waggon will be run on to this framework, and the
material tipped into the space below, until the drawing machinery is ready to
CHAP. II.]
LOADING SKIPS IN SHAFTS.
599
raise it. The angle of the upper portion of the level above the plat should be
taken off, so that the rope may not be cut when the kibble is drawn aside.
When such a plat has to be carried out in ground of a difficult character, it is
usual to put in the timbering temporarily at first, then, when the level and
stopes have been fully extended, the plat is formed and the timbering com-
pleted. A plat is begun half the height at first at the two ends, leaving a
solid pillar in the centre. After driving a short distance and the roof requires
supporting, leg pieces should be put in, which must rest on longitudinal
sole pieces. Then, when the two sides are driven as far as required, the
central pillar may be taken away
and permanent timbering put in.
It is essential that a well-con-
trived recess for the skips should
be constructed. The skip not
being arranged so as to leave the
guides, there is a method adopted
at each recess, sometimes of
chains, sometimes of bars of iron
hinged against the recess, and of
a height equal to that of the skip.
These being reversed or those
extended, the skip rests on them,
and can be held at any level the
filler requires.
As a rule the loading is done
as if for kibbles—the large stones
of ore are thrown in by hand,
then the small pieces are lifted
with a shovel. Two fillers are
employed at this work.
Fig. 161 represents a recess
of this kind in Wheal Buller.
The veinstone of chlorite and
fluor-spar, being soft and friable,
breaks into small fragments, and
admits of a hopper being placed
with a trap, which accelerates the
Fig. 161.
lading. The skip, when it arrives on the bars, has a covering placed on it at
the hinges, the trap is raised, and the filler has only to direct the flowing of
the ore into the vessel. This arrangement is certainly advantageous when
the nature of the stuff will permit of it.
The recess for the skip above ground is sometimes divided into two parts,
the one movable on hinges and the other fixed projecting over the waggon.
Two bars of iron, supported on the guides, form the head of the inclined plane;
the skip is turned over and emptied in an instant. As soon as it is empty
the double hook is taken away, the door beaten down and fastened. The
lander waits the signal from below, the skip is a little raised, the workman
hastens to release the skip, and the movement-up or down-commences. It
600
[BOOK III,
PRACTICAL MINING.
has been stated that the distance between the levels, which in 1778* we are
told was generally 8 fathoms, has been increased to 10, and occasionally to
12 fathoms.
There are no good reasons why any fixed distances should be
established for the distances of the levels; they should in all cases be
regulated by the character of the lode and the facilities of winding in the
shaft. When lodes are large, with short deposits of ore, a less distance than
10 fathoms between the levels may be very advantageous, but in many cases
wider distances may be judiciously adopted. Levels at short distances
entail a heavy cost. Mr. Darlington gives † the following statement of the
extent of the levels driven in the Consolidated mines, Gwennap. In 1838 the
adit had been extended to 1,678 fathoms. Below this 32 levels were
driven, 25 of them 10 fathoms, and 7 of them 5 fathoms apart. The winzes
measured 13,631 fathoms, and the shafts 4,360 fathoms. The proportion,
therefore, was 49 feet of drivage to 6 feet of shafts, and 15 feet to 6 feet
sunk in winzes. Had the levels been regularly driven 15 fathoms apart, it
would have diminished the total horizontal length about one-third, and thus
shortened the drivages by 11,883 fathoms, which valued at £5 10s. per
fathom would involve a saving of £65,356, due exclusively to the extension
of distances between the levels. By these remarks it is not intended to
intimate that this large sum was lost by the proprietors, or that it would
have been judicious to place all the levels 15 fathoms apart, but rather to
invite the attention of mining agents to a consideration of this subject, and
to convey to them an idea of the
saving of expense, which under cer-
tain circumstances might be effected.
The annexed woodcuts, Fig. 162,
show the characters of the hooks
employed, which afford facilities for
relieving the skip, and are so contrived
as not to release it during its ascent
or descent, as such an accident would
prove fatal to the men below. Several
schemes have been tried, but the two
****
Fig. 162.
represented, where side and end views are shown, are found to answer
most satisfactorily.
The left-hand hook is secured from unshipping by means of an iron pin
passed through the return of the hook above a loop dropped over for the
purpose; and the right-hand figure shows how similar security may be
obtained, by a spring acting against a continuation of the hook, which is thus
converted into a ring.
Subterraneous working. The methods adopted in working a metalli-
ferous mine must vary with the conditions under which the more valuable
portions of the lode occur. It frequently happens that the rich ore is mixed,
in the lode, with barren mineral matter, which is commonly called vein-
stone. In most cases it is necessary to break out all the deposits in the
lode, but it is not always necessary that all should be taken to grass; con-
* Pryce, "Mineralogia Cornubiensis."
"Records of Mining and Metallurgy." By John Arthur Phillips and John Darlington.
CHAP. II.]
DIAGRAM OF METAL MINE.
601
siderable quantities of the useless portions are thrown back to fill up the
empty spaces, and special methods are required to properly meet the
conditions as they occur.
The valueless stones should be judiciously placed
in the void left by the excavation, so as to form a good support for the
unbroken rock.
The conditions of working small narrow lodes vary, in many respects,
from those employed in mining broad ones. In either case a vertical shaft
must be constructed, and by means of cross cuts at various depths the lode is
reached. The intervals between the cross cuts vary from 8 fathoms to 12, or
even, as before stated, in some cases to 15 fathoms. An inclined shaft is
frequently used, especially in small and doubtful lodes, as it serves especially
to explore the lode as it is sunk, but there are numerous advantages in a
well-constructed vertical shaft. The cross cuts having reached the lode, the
miners begin to drive galleries upon it, and if the exploration assures them
of productiveness they begin regularly to work it away. The disposition
of the richer parts of the lode will determine the condition and extent of
the workings. The lode, if of fair average quality, will be divided into a
series of galleries, at different levels. For the sake of ventilation and for
bringing away the ore, a series of small shafts (winzes) are cut through, from
one level to another; their distances from each other being uncertain, varying
with the character
of the lode from 15
fathoms to 30 fa-
thoms. This is con-
tinued along the
strike of the lode
until the extremity
of the sett (working
area of the mine) or
until the end of the
richer portion of the
lode is reached.
To
the depth within
the sett-there is no
limit, except that of
the cost of bringing
the ore to the sur-
face, which is con-
stantly increasing
with the depth.
Levels are driven
whenever the lode is
intersected with a
new cross cut, and
winzes are cut
through as the levels
L
L
SL
A
W
W
L
W
W
L
L
Fig. 163.-S¹ is the engine-shaft, usually called the sump-shaft. S² is a
second shaft, which is mainly used for winding the ore to the surface.
AA is the adit level, which intercepts much of the water percolating
from above, and to which all the water from the lower parts of the mine
is pumped through the engine-shaft, and discharged into the valley at
A. LL indicates that all the horizontal lines are levels driven at
uniform distances into and along the lode, by means of which the work-
ings are carried on and the ore is removed. W W and all the short
vertical lines connecting the levels, are winzes, by means of which the
miners are enabled, by stoping, to break down the ore from the lode.
are lengthened. The annexed diagram, Fig. 163, of a portion of the Consoli-
dated mines will, it is hoped, convey a correct idea of subterranean operations.
602
[BOOK III.
PRACTICAL MINING.
According to the richness of the lode, the winzes are, or should be, regu-
lated, in order that the ore worked out in cutting them should pay the cost, or
at least part of the cost, of sinking or rising. It will be evident by this that
a metalliferous mine consists of a series of blocks or rectangular masses, each
bounded by two levels, cut at intervals from the shaft S S, and by two winzes.
The work of the miner now consists in removing such blocks, or such
portions of them, as are productive of metalliferous ores. A well laid-out mine
will have a number of levels driven, and winzes cut, as the preliminary stages,
so that a regular supply of ore may be obtained for months or for years, by
removing the blocks one after the other. The "ore in sight” determines the
commercial value of the mine, and it is only by opening upon the lode in this
way that the quantity of ore in it can be determined. This is removed by
overhand stoping and underhand stoping. Overhand stopes are formed by the
removal of a block at its lower corner. A portion of the lode is broken down,
perhaps to the height of 6 feet, thus raising the height of the level irregu-
larly to that extent. The broken matter falls on the floor of the level, the
metalliferous parts are picked out, and either allowed to accumulate or
placed in barrows, or trams, for removal, and the rock without any mineral
of value (attle or deads) is cast on one side, and placed on a wooden stage
(stull) or on a stone arch, or used to fill exhausted spaces.
When the first stope has been advanced a fathom or more, a second is
commenced, and the broken stuff falls into the level, to be treated as before.
After a time a third stope is formed above the second, and thus is created a
series of excavations, one above the other, parallel to the strike of the lode.
Thus eventually we have a series of working places like steps, one a little
behind the other. When a large space is formed by the excavations made
by the processes described, the workings are carried on, as in any large
subterranean working. (See Fig. 164.)
(See Fig. 164.) The engraving shows the excava-
tion going on in the second stope, and the work in an advanced state,
exhibiting the construction of the leading lengths. The support required for
carrying the upper stope and the tops may be obtained by props raking
inwards, placed where they are not in the way. Where there is confidence
in the stability of the square timbering of the level, a portion of the weight
might be temporarily carried by propping. This mode of proceeding is best
avoided, unless the circumstances of the case compel the miners to have
recourse thereto. The rubbish is allowed to fall down, and thus it forms an
irregular heap resting at the angle of repose, from which the term overhand
stopes is derived. The broken ore from one stope falls on the rubbish of one
below it, until it finally reaches the level, from which it is taken away in tram-
waggons or in barrows.
Stopes are thus continued until they reach the winze on the other side of
the block, and thus, at length, the whole of a block is removed. Usually a
large portion of the lode is waste stuff (dcads or attle), which should be carefully
arranged so as to supply the place of the richer ore which has been taken
away. The back of the lower level is well lined by a timber stull, or by a
stone arch across the lode. One, or the other, carries the deads, and on these
level, the winzes being kept open by props and
rests the floor of the upper
laths as already described.
CHAP. II.]
STOPING IN LEVELS.
603
Underhand stoping consists in beginning the work upon the block at one
or other of its upper corners. The first stope is taken from the floor of the
upper level to the depth of about 5 feet, and when this stope has advanced
far enough a second stope is commenced. The deads, after the ore has been
picked out, is thrown on to stulls, which are usually put up for every stope.
Underhand stoping is the reverse of overhand stoping. It is always advis-
able to maintain a few good roadways in the midst of the deads for conveying
the mineral matter to the nearest winze, to be thrown into the lower level,
or drawn by means of a windlass to the level above, from which it is sent to
the shaft, through which it is to be drawn to the surface.
DREIPFR-E
ורטונה
|BLASTOIS
Fig. 164.
Sometimes these methods of stoping are carried on without a winze.
Overhand stopes are begun by a rise, working away the lode upwards; and
underhand stopes by a sink, working away the lode downwards. Each time
that a portion has been risen or sunk, new works are begun both right and
left.
Underhand stoping is frequently adopted in the German mines, and
it is the usual practice in the mines of South America. It is rarely adopted
in this country.
Sometimes small shafts are constructed at short intervals in the middle of
the deads themselves. They are then built up with stones from the top of the
level, and are continued gradually as the pile of rubbish increases in size.
604
[BOOK III.
PRACTICAL MINING.
The ore is generally allowed to fall directly into the level below, but some-
times a strong door is placed at the lower end of the shaft, and it is permitted
to become full, and then the door being opened, the ore is arranged to fall
at once into the waggons or barrows. It will be seen by this description
that the working away of the ore is rendered easy by the system of working
in stopes or steps, and the filling of the waste spaces is effected economically
by using the material obtained on the spot where it is required. If it is
thought to be advisable, a block or rectangular mass of ore can be speedily
removed by placing a number of workmen to stope it at different places.
Economy, in general, points favourably to overhand stopes, since the
quantity of timber used will only be that which is required for one long
stope; but in the system of underhand stoping, stalls are required for nearly
every stope in the block. The cost of the timber therefore regulates the
system which should be adopted for working a mine.
Overhand stoping is most conveniently, and economically, employed when
working in the wider parts of lodes, provided the rock is sufficiently coherent
to allow the workings to be carried the whole width of the lode. By over-
hand stoping the lode is broken away with greater facility; the arrange-
ments for stowing the valueless portions in the waste places are considerable,
while the richer ore is sent into the levels and conveyed away with the least
trouble. Beyond this, overhand stoping is generally regarded by the miner
himself as the safest, especially where the walls of the lode are bad, and do
not allow of the stulls being firmly fixed.
When the lode is much decomposed, and weak and friable, or when such
a lode contains, as they often do, rich silver ores, or others equally valuable,
underhand stoping is to be preferred. In the latter case-of rich ores-it
must be remembered that by overhand stoping the ore falls on a floor
made up of the deads of the understope, and the fragments of silver ore,
especially the smaller ones, would be lost in the crevices between the stones
of the rubbish. In underhand work the ore broken out falls on those parts
of the lode which are still intact, and the miner has to remove this, and
examine every piece as he does so, before he can proceed with his excavation.
In a good-sized regular lode the chief levels should be on the foot-wall side,
and connected so as to secure proper ventilation by winzes, one with the
other. Cross cuts are now driven out of the main level, and carried on to the
hanging wall, these being carefully timbered, and all waste spaces filled in
with the refuse stones. By driving on the lode, portions of it are gradually
worked away, and if it is thought advisable, several sections may thus be
removed simultaneously.
In large lodes we often find many branches enclosing large masses
(horses) of the same kind as the rock in which the lode occurs. Frequently
the miner in cross-cutting meets with these horses before he reaches the
upper wall of the lode. After an examination of each horse, if it is found to
contain no ore, it is left standing, and the cross cuts are driven on to the
upper wall of the lode, and two separate workings are established-on the
hanging wall and on the foot-wall of the lode. When refuse matter cannot be
obtained to fill up the spaces from which ore has been removed, it becomes
imperative to obtain waste stuff from some other source, or if it cannot be
CHAP. II.]
WIDTH OF LEVEL IN LODES.
605
obtained without the cost of quarrying it, conveying it underground, and then
training it to the place for which it is required, the supporting pillars may
be removed and the roof allowed to fall in. This is a process which is
always attended with some danger.
In cases where the lode is too wide, and the strength-the coherence of
the contents-of the lode is not sufficient to support itself, a level is often
driven in the middle of the ore, unless one of the walls offers sufficient
security. The level being in the middle of the lode, the other parts are
taken away by working from one side (wall) to the other, or by cross-cutting.
The strength of the lode determines the width which can be given to those
cuttings, and their direction is settled by a consideration of the line most
suitable for working away the metallic ores. One set of cross cuts (com-
monly called drivages) having been finished, and then packed with the deads,
another cut is worked, and another section of the vein removed, until at last
all the ore has been taken away, and its place supplied with the rubbish
cautiously stored. When these packings of the deads have stood for some
time they settle down, and the pieces get cemented together by the water
percolating through them, depositing either lime or oxide of iron, and the wall
becomes as firm as any part of the lode itself. When consolidation has taken
place, that portion of the lode which is immediately beneath the deads
can be removed, leaving a small wall of support, at either end, for the deads
to rest upon. Where the deads are not sufficiently solid, an arch of ground
should be left, which may be eventually removed when all the other work
is finished. It must never be forgotten that at all times channels must be
preserved for the circulation of air, ventilation being essential to secure the
health of the men. If the lode has proved rich and continuous in several
levels, and stoping has been carried on in the most complete manner, the
spaces between the levels will be vacant unless by judicious timbering or
walling and packing of the rejected mass the cavities have all been filled,
except where channels have been preserved for the purposes of ventilation.
This is often neglected or incautiously carried out, and great waste is the
consequence. Often, especially when the mine has been worked in stratified
deposits, a subsidence of the superposed stratum will take place, disturbing
all the arrangements which have previously been made.
The following remarks by Sir Henry de la Beche are so much to the
purpose that they are quoted entire.*
"The open spaces whence ore has been taken vary considerably, as must
happen according to the breadth of the lodes in those situations and the
amount of ore in them, for the lode may be broad or big enough, and yet not
contain ore in sufficient quantities to be worked. There can be scarcely any
rule in a variable thing like a mineral vein or lode as to the breadth of the
parts which may be worth working, for though small, with little ore in
some places, it may be several feet across in others, and be there rich; or
it may be thin and rich in one place and broad and comparatively poor in
another, so that it may even be questionable how far it may be advisable to
take that portion out at all. These are matters upon which the chief agents
decide according to their skill and judgment. It is usual in mines, particu-
* "Report on the Geology of Cornwall, Devon, and West Somerset." By Henry T. de la Beche.
606
[BOOK III.
PRACTICAL MINING.
larly those worked on the large scale and for a continuance, not to take out
all the ore which could be immediately got at if thought necessary, but
to leave it here and there to be worked as the general prospects of the mine
may require, and to which the miners return if less ore is raised generally in
the adventure than could be wished. The ores thus left in various places are
often termed the eyes of the mine, and when it may be necessary, in aban-
doning the mine, or from any pressing circumstances, to remove them, it is
termed picking out the eyes of the mine. In some mines these 'eyes' are very
valuable, and much skill and judgment are employed by the captains in so
arranging the workings that a general good supply of ores may be obtained."
Cases do occasionally arise where the lode does not furnish any deads for
stowage, and the produce of the mine will not cover the cost of bringing
stones for stowage from a distance. Then the advisable plan is to divide
the lode into sections and drive levels at the bottom of each section, leaving
a solid roof above. In mining in this manner the excavations in one division
should correspond exactly with those above, and thus secure that the
pillars left in the upper section rest on the solid pillars beneath. The
quantity of ore that can be safely removed in this way depends on the nature
of the rock or of the lode, and demands all the care and consideration which
the agent can give to it. When the more valuable portions have been taken
away, if it is thought desirable to obtain the other less valuable portion, the
miner works away the innermost pillar, or standing mass, and eventually
breaks through it, allowing the upper portion to fall. He then proceeds in
the same way with the next, and so on until no more good ore is left, or it
becomes too dangerous to attempt to obtain it. A neglect of attention to
these points has sometimes led to a serious subsidence of the upper rocks, or
parts of the lode, resulting in severe injury, or even death, the miner getting
crushed beneath the falling mass, and considerable loss to the proprietor of
the mine.
CHAPTER III.
VENTILATION OF MINES-DRAINAGE OF MINES, ETC.
Ventilation of Mines.-The ventilation of metalliferous mines is not sur-
rounded with the difficulties and dangers which are always present in
collieries. Explosions of the mixture of light carburetted hydrogen with
atmospheric air, which are common in coal mines, are rarely heard of in
metalliferous mines. The Van mine in North Wales is a singular example of
the production of this gas from natural causes. At wide intervals of time a
little explosive gas has been met with in the Cornish mines, and in the lead
mines of other counties, especially when the lead lode has been worked near
to, or in, the Coal Measures.
There are two or three causes existing in metallic mines which tend to
render the air injurious to the miners. The burning of candles, the explosions.
of gunpowder, and the natural processes of respiration, each tend to deprive
the air of some of its oxygen, and thus deteriorate it; and, by the processes.
of combustion and respiration, a considerable proportion of carbonic acid is
constantly being added to the air. Sulphurous acid is given out by the
burning of gunpowder, and nitrous acid, by the decomposition of the nitrate
of potash, is also produced in small quantities.
Where the mines are worked in Limestone strata large quantities of
carbonic acid are constantly being poured into the air from the rock itself.
The difficulties of ventilating the workings in the close end of an adit have
been already spoken of. The vitiated air of the close ends of levels is often
so largely impregnated with this heavy gas, as to be unable to support com-
bustion, and consequently insufficient for the healthful maintenance of vital
power.
Under ordinary circumstances, when a mine is properly opened, a natural
process of ventilation is established, depending on the temperature of rocks
in which the excavations are made. A very simple experiment will prove
that it is easy to establish an ascending and descending current of air. If a
very tall glass jar is taken, and a lighted taper placed at the bottom of it,
in a very short time so much of the oxygen will be consumed, or converted
into carbonic acid, that the flame will be considerably diminished, and would
in a short time be extinguished. If now a long piece of pasteboard be passed
so as to reach nearly to the bottom of the jar, a down current of pure air will
be established, while the warmed and vitiated air will steadily ascend and the
flame burn brightly. Upon this principle depends the power of ventilating
the deepest and most extensive mines.
It has been already stated that the temperature of the rocks increases
608
[BOOK III.
PRACTICAL MINING.
in an uniform ratio. Mr. R. W. Fox established the fact that the tem-
perature of our mines increases with the depth in a regularly dimin-
ishing ratio. The following table is based on the extensive observations
of Mr. W. J. Henwood*:
Surface to
50 Fathoms.
50 to 100
Fathoms.
100 to 150
Fathoms.
150 to 200
Fathoms.
200 Fathoms
and beyond.
Mean.
Depth. Temp. Depth. Temp. Depth. Temp. Depth. Temp. Depth. Temp. Depth. Temp.
Fms. Degrs. Fms. Degrs.
Fms. Degrs.
Fms. Degrs. Fms. Degrs. Fms. Degrs.
St. Just
St. Ives
Marazion
Gwinnear.
25
Helston
•
Camborne
Redruth.
St. Agnes
St. Austell
Tavistock
~ ~ ~ ~ ~ 3 lå
28
33
28
31
2I
n∞ m∞ 1-
51.45 70 50.17
128 62.75
156 61.01
54.16 73
59.64
119 67.0
197 63.01
228 720
58.62 64
61.66
131 71.33
57 I
78
63.53
131
66.0
167 76'0
| |
56.6
80
62.1
133 66.1
190 68.5
53°3
78
61.5
125 66.54
168 67.17
39
33 52.7
58.5
76
58.3
130 70.64
177 86.07
245 89.17
30 54.3
Mean
30 54.87 72
75 63.9 129 69.0
52 55.0 III 71.0
67
58.75
118 64.16
60.80 127 67.43
154 72.25
160 67.75
220 88.76
237 80.0
ΙΟΙ
95 57.84
129 63.56
7663.87
IOI 63.4
134 66.66
9862.13
132 71.27
99 65.91
136 70.62
72 59'7
173 78.0 240 85.52
II2 66.88
The mean temperature at nearly equal depths in Granite and Slate rock
is given as follows:-
Granite.
Slate.
Depths.
Depth. Temp. Depth. Temp.
Fms. Degrees. Fms.
Degrees.
Surface to 50 fathoms
25 52.67 30
55'9
50 to 100
71
"
57.68
73
61.9
100 to 150
132
65.0
125
68.14
""
150 to 200
161
65.71
174
79.17
200 fathoms and beyond
240
76.15
241
89.4
Mean
94
68.35
116
68.89
The mean annual temperature, at the depth of three feet from the surface,
has been determined by Mr. Foxt:-
At Wheal Gorland (Granite)
•
At Dolcoath (Slate).
At Falmouth (Slate)
Mean
Degrees.
48.09
48.94
50.67
49.86
Mr. Henwood's experiments led him to concur with Mr. Fox in be-
ginning his computations at 500 yards. The temperatures given in the
above tables do not coincide in all cases, but the inequalities are so slight
that we are justified in considering the mean of the surface temperature at
*W. J. Henwood, "On the Temperature of the Mines of Cornwall and Devon." ("Transactions of
the Royal Geological Society of Cornwall," vol. v.)
† R. W. Fox, "Cornwall Geological Transactions."
CHAP. III.]
TEMPERATURE IN DOLCOATH.
609
50°. Numerous observations have been made both in this country, on the
continent of Europe, and in America, in mines, and Artesian wells, hoping to
determine the rate of increase in subterranean temperature. None of these
are quite free from the suspicion of errors. In evidence given by the author
before the Royal Coal Commission, the whole question has been examined,
and to that the reader, who is interested in the question, is referred. For
the purposes of the present consideration it is sufficient to know that there
is a regular rate of increase, about 1° Fah. for every 50 feet of depth,—the
ratio of increase being, to the depth which has been penetrated, a constantly
diminishing one.
The most recent observations which have been made are those of Captain
Josiah Thomas, of Dolcoath mine, the results of which were read before a
meeting of the Mining Institute. The following portion of that communi-
cation is of such interest that it deserves to be quoted:-
"Mr. W. Jory Henwood, of Penzance, in a work published in 1871, gives
the results of many hundreds of observations made in mines in every district
of Cornwall, extending over a series of years. His general deductions from all
the observations are, that Slate rocks are warmer than Granite, that rocks are
warmer than lodes, and that copper lodes are warmer than those lodes that
produce tin. His conclusions are that the increase of heat downwards to a
depth of 240 fathoms was in Slate rocks 1° for every 38 feet, and in Granite
1° for every 55 feet in depth.
“In a work on Geology just published by Professor Archibald Geikie,
Director of the Geological Survey of Great Britain, he states that according
to present knowledge the average rate of increase amounts to 1° Fah. for
every 50 or 60 feet of descent, and this rise is found whether the boring
be made at the sea-level or on elevated ground.' Finally, Professor
Everett has recently drawn up a summary of results of reports of under-
ground temperature made for the British Association, from which it appears
that the greatest increase of temperature was in 'shale' in a boring near
Glasgow, 450 feet deep, where the ratio was 1° in 30 feet; and that the
lowest rate of increase was in a mine in Bohemia in quartzose rock, 1,900
feet deep, where the ratio was 1° in 135 feet. The deepest mine in which
experiments have been made was in Ashton Moss Colliery, near Man-
chester, which was at the time 2,790 feet or 465 fathoms deep; and in this
mine the rate of increase was found to be 1º in 77 feet.
I
The mean increase
of temperature in all the experiments made in different parts of the world
is said by Professor Everett to be 1º in 64 feet.
"I have of late been making some observations on the temperature of
Dolcoath mine, the lower workings of which are in Granite, and I thought
the results might be somewhat interesting, as I am not aware that any
experiments have hitherto been made in Granite at so great a depth. Mr.
Henwood's experiments were for the most part made in the water which
issued from the rocks; but this scarcely seems to be the best method of
obtaining the most accurate results, for it is well known that the temperature
of water is affected by chemical action taking place in the lodes, as at Clifford
Amalgamated mine, in Gwennap, where the temperature of the water was 116°.
It must also be necessarily affected by the cold surface water passing down-
610
[BOOK III.
PRACTICAL MINING.
ward through the lodes and cross courses. In the observations that I have
made, therefore, I have had holes bored two feet in dry rock, in which I have
inserted one of Negretti and Zambra's slow-action mining thermometers.
The thermometer, which is about 10 inches long, was put down to the
bottom of the hole. The upper part of the hole was then plugged up with
woollen material and covered on the outside with soft clay, so as to keep
out all the atmosphere. The thermometer was left in the holes for various
periods, varying from half an hour to a week. The results of the trials are
as follows:
Fathom Level.
Fathoms Perpen-
dicular below
Temperature
of Rock.
Surface.
Temperature
of Air.
At the I2
""
40
""
125
146
170
250888
42
64 deg.
65
65
""
67/2/
5680
65 deg.
66/1/
""
68
""
65
66
""
""
""
""
302
314
70
""
352
354
83
03
71
""
""
81
""
"In reference to the temperature of the rock at the 170-fathom level, which
was lower than at the 125-fathom, it should be observed that a cold current
of air had, for some time past, been passing through the 170-fathom, which
no doubt diminished the heat of the rock, at least to a depth of some feet. The
thermometer at the 12-fathom level was allowed to remain in the hole three
days, and that in the 352-fathom level was in the hole seven days. The
temperature of the rock at the 12-fathom level, 42 fathoms (perpendicular)
below surface, was found to be 64°, and at the 352-fathom level (312 fathoms
deeper) 83°, being an increase of 19°, or 1° in 98 feet. I think that in taking
these two extreme points we have a fair test of the real temperature of the
rocks at Dolcoath, and the true rate of increase. The temperature in the
intermediate levels may possibly be affected by currents of air passing
through them, and by other causes; but the hole at the 352-fathom level was
in clean Granite, about 15 fathoms inside any draught, and 4 fathoms behind
the end, in new ground recently driven through, and therefore we may
suppose that the temperature observed at this point was the natural heat of
the rock.
"The results of my present observations are very different from those
that had previously been made in Dolcoath mine, as recorded by various
writers. Sir H. de la Beche says that from a report made to the British
Association in 1837 the temperature in Dolcoath at 230 fathoms deep was
about 75°; and that the heat increased 1° for every 51 feet. Mr. W. J.
Henwood says that the temperature in 1822, at 230 fathoms deep, was 75°,
and that it increased 1° in 54 feet. He also says that in 1857, at a depth
of 272 fathoms, the temperature was 73°, or 23° less than in 1822, although
the mine was 42 fathoms deeper, and that the rate of increase was 1º in
70 feet.
I now find that the temperature at the 352-fathom level, 354
fathoms perpendicular from surface, is 83°, and that the rate of increase as
before stated is 1º in 983 feet. But although the actual results of various
611
CHAP. III.]
NATURAL AND ARTIFICIAL VENTILATION.
observations, both in Cornwall and in other parts of the world, somewhat
widely differ, yet it is a remarkable fact that everywhere, without a single
exception, the heat increases as depth is attained, and nowhere has the
temperature been found to be less in depth. Professor Archibald Geikie
remarks that, 'Supposing the rise of temperature, as observed to the depth
reached, continues at the same ratio, the temperature at 20 miles would be
1,700°, and at 50 miles deep 4,500°.'
In connection with subterranean temperature, the important point with
which we are more immediately concerned is that the heat does increase
with the depth, and consequently that the air becomes warmer, and has a
constantly increasing tendency to flow upwards. This may be illustrated by
a very simple experiment. Connect two long glass tubes together by a
U-shaped piece of metallic tube at the bottom. The temperature of the air
in each tube being the same, it remains undisturbed, but the slightest appli-
cation of heat-even the warmth of the hand-is sufficient to establish an
upward flow in one tube, and consequently to produce a downward current
in the other. On a large scale this is what takes place in the working of a
mine by what has been called natural ventilation.
In 1813 an improved system of ventilation in our collieries was introduced
by Mr. Buddle, of Newcastle-upon-Tyne, by providing several channels for
the air, instead of passing it through a single course. It has been hitherto
the usual practice to fix a furnace at the bottom of one shaft in collieries, so
as to rarefy the air, by which it was made to ascend. This is called the
"upcast" shaft. Consequently the colder external air, which is of greater
weight, then descends another shaft, which is called the "downcast" shaft, and
by well-devised arrangements the current of air is circulated through all the
devious windings of a colliery. The furnace system of ventilation is rapidly
passing out of use, mechanical ventilation having been proved to be much
more economical and effective. Where the colliery has not two shafts-a
state of things which is being discontinued-it has been the custom to
obtain the same result by dividing the single shaft by a brattice, which may
be either of prepared cloth or a division of thin boarding. In either case it
is not difficult to produce an upward flow of air from the depth of the pit,
and consequently to establish a downward current of fresh atmospheric air.
A committee of the North of England Institute of Mining Engineers
recently made some investigations as to the efficiency of different kinds of
mechanical ventilators. These experiments bore directly on the ventilation
of collieries, but with the increasing depths of our metalliferous mines, and
the rapid extension of the workings, it will become an imperative necessity
to adopt, to a greater or a less extent, similar mechanical appliances in them
to those which have been found to be so useful in our collieries.*
With this idea, it is considered important to place in the hands of the
metalliferous miner a table of the efficiencies of mechanical ventilators,
compiled from the report, by Mr. Henry Davey, of Leeds † :—
t:
* See "Transactions of the North of England Institute of Mining Engineers," vol. xxx., 1880-81,
pp. 288-290.
"Mining Machinery." By Henry Davey. (Excerpt Minutes of Proceedings of the Meeting of the
Mechanical Engineers in Leeds, 16th August, 1882.)
R R
612
LBOOK III.
PRACTICAL MINING.
Name of
No. Ventilating
Machines.
Diameter.
DIMENSIONS OF ENGINES.
EFFICIENCIES OF MECHANICAL VENTILATORS.
GENERAL REMARKS.
Volume of Mean Water Percentage
Gauge at
Drift Door.
of Useful
Effect.
Width, &c.
Theoretical
Displacement
per Minute.
No. Dia. Length
Diameter
of Inlet.
Weight.
of
Cyls. Cyls.
of
of
Stroke.
Direct-
acting or
geared.
Air per
Minute.
DIMENSIONS OF VENTILATING MACHINES.
Ft. in.
Ft. in.
Cub. ft.
I
Guibal
Fan
50 0
12 O
Ft. in.
15 O
Tons.
50
No. In.
Ft. in.
Cub. ft.
Inches.
I 42
3 6
Direct
108,422
3.30
Per cent.
40'00
2
Do.
46 0
14 10
13 0
I
36
3 6
Direct
246,509
1.85
52.95
3
Do.
40 0
12 O
14 O
24
I
36
3 0
Direct
170,581
1.46
47.95
4
Waddle.
""
45 O
Inlet
6 6
15 0
I
32
4 0
Direct
163.312
3'08
52.79
Periphery 1 5
5❘ Schiele
""
12 0
2 I
I
I
25
20
2.57 to I
157,176
L'91
46.12
6
Do.
""
96
Inlet
Periphery I
3 2
8
8 0
1
I 20
I 8
2 to 1
106,570
2.03
49.27
7 Lemielle
8
Struvé
9❘ Nixon
Chamber 22
Drum 15 O
2 Pistons 18 3
2 Pistons, 30 ft. long,
20 ft. high
6
Height 32 0
9'9 rev. 108,900
I
55
60
Direct
47,307
1*37
23.40
Stroke 7 0
Stroke 7 0
61 rev. 47,827
7.19 rev. 120,790
I
24
4 45
4 to I
43.793
5.11
57.80
I
36
60
Direct
72,595
2.74
45.91
ΙΟ
Root
2 Drums 25 O
13 0
II
Cooke
2 Drums 15 0
Casing 22 O
II 6
16.71 rev. 96,918
17.92 rev. 80,640
2
28 4 0
Direct
89,772 3.29
47.84
I
25
3 6
Direct
54, 190
I.12
37.33
12
Goffint
2 Pistons 13
2
Stroke
10 7
91 rev. 53,020
1
2
I 15 10 7
Direct
36,286
0.71
25.79
CHAP. III.]
VENTILATING MACHINES.
613
In 1764, Jars, in his "Voyages Métallurgiques," laid down the principles of
mechanical ventilation; and Mr. Spedding, in 1760, greatly improved this
system in the North of England. In mines where no mechanical appliances
are employed for ventilating the workings, precautions should be taken
to keep the levels well open, and to prevent any leakage of air into old
workings. Care should be also taken to convey the air from one level to
another, and to all the various working places. This is of course effected
by placing properly-constructed stops in certain places, so as to produce a
current, regularly flowing in one direction. It has been considered a good
rule never to allow the velocity with which the air traverses the levels to
exceed 5 feet per second, or to fall short of 6 inches per second. Bellows
and fans of various descriptions have been employed for ventilating purposes.
The bellows employed have usually been of the compound character,
emitting a continuous blast of air. Fans of various descriptions have been
employed with different degrees of advantage. M. Ponson has given the
following table, from which may be gathered the actual value of several
of the ventilating fans :-
Names of the Ventilators.
Maximum
of Bulk
Extract.
Correspon-
dent
Depression.
Useful
Power in
Horses.
Depression
Maximum.
Correspon-
dent Bulk of
Air Extract.
Useful
Power in
Horses.
Cub. yd.
Cub. yd.
With Curved Wings (Combs)
6.08
0:"826
I.27
I⚫"495
3.70
I'44
With Plane Wings (or centri-
fugal force)
9.24
I."968
4.61
2."282
I.304
0.76
With Screw (Notte).
8.61
0."826
1.80
0."983
5.640
1.40
With Spiral (Paquet)
13.83
I "IOI
3.87
1."770
8.000
3.60
With Mill Wings (Lesoigne)
•
12.16
0."511
1.98
0."511
12.160
1.98
With Wheel (Fabry)
16.84
1.°613
6.96
3."385
5.600
4.82
It is seen by this table that the maximum of the dislodged air is some-
what inferior to 17:32 cubic yards, and that the maximum of the depression
obtained is 3" 385. Now, as the latter indicates precisely the measure of the
ventilating power of the apparatus, the most perfect will be the one which
can reach a great depression, and at the same time dispose of a considerable
amount of air. None of those mentioned in the above table performs these
conditions, for in all of them does the volume of the dislodged air decrease,
with excessive rapidity, in proportion to the increase of depression. The
maximum of the one corresponds with the minimum of the other.
It is clear, then, that at a point very close to the maximum of the depression
indicated above, these machines must work without producing any effect,
as the air entering almost equals the amount of the dislodged air.
M. Lemielle's ventilator with pneumatic wings has been extensively
used. It extracts on an average 16 cubic yards of air per second, and its dis-
tinguishing feature is that it possesses the advantage of dislodging that
volume of air under considerable depression.
The following table was constructed—by M. Le Verrier, Engineer to the
Imperial Administration of Mines at Lille-to show the results of experiments
made in a mine near Douai :-
RR 2
614
[BOOK III.
PRACTICAL MINING.
Number of Turnings
of the Ventilator
per Minute.
Volume of Air
extracted from the
Mine per Second.
Depression.
Maximum.
Velocity of the Air per
Second in the Gallery
which conducts to the
Ventilator. (27 square
feet, 24 section.)
Useful Power
in Horses.
Volume of Air
extracted by each
Revolution of the
Ventilator.
Cubic yards.
Yards.
Cubic yards.
ΙΟ
8.00
2. "731
3.20
3°52
48
17
14'00
4 "133
5.60
14.70
49'51
21
26
16.87
5."511
6.88
23.61
49.32
21.53
6."299
8.33
34°44
49.68
The obstacles to the motion of air in the levels of a mine are in direct
proportion to their length-to the perimeter of their section-to the square
of the velocity of the current-and in inverse proportion to the area of the
section. The longer the passages, the narrower the galleries are, and the
more rapid the current, the more considerable will be the depression. The
miner should, therefore, give the preference to a ventilator which will produce
the most powerful depression. M. Lemielle offers to furnish the miner with
apparatus capable of extracting air from the works, and with the necessary
depression from 40 cubic yards to 133 cubic yards per second.
Screws of various kinds have been employed in small pieces of apparatus
for sending air into close ends. The Archimedean screw has been employed
for this purpose with considerable advantage. The duck machine, as it has
been called, consisting of two inverted tubs working up and down in
vessels of water, acting by exhaustion, was first introduced by the late
Mr. John Taylor, and it was employed by him when constructing the
tunnel at Tavistock. The same principle has been patented by Mr. Struvé,
of Swansea, and applied with much success in some of the collieries of South
Wales. Mr. Low, of Loft Wen, near Wrexham, invented an apparatus
composed of a series of small tubes fixed vertically around the pit at any
convenient depth, and heated by steam drawn from the engine boiler. The
introduction of steam heats the tubes to about 212° Fah., and the radiation of
heat from their outer surface causes a considerable rarefaction of the air in
the shaft, and thus ventilates the mine.
Mr. W. Teague, of Tincroft mine, Cornwall, has introduced a ventilator
A
Fig. 165.
the principle of which
will be at once under-
stood by the annexed
sketch.
Fig. 165 is an air, or
steam, ventilator. A trial
of it has been made at
Carn Brea mine, Corn-
wall, on which occasion
over 8,000 cubic feet of air
were passed through the machine in one minute. This was accomplished
by a 1-inch pipe with four jets, supplied with a pressure of air to the extent of
60 lbs. to the square inch, passing through a 4-inch pipe with two outer rings, A.
These outer rings produced a powerful exhaustion. At the same time the
CHAP. III.]
BIRAM'S ANEMOMETER.
615
principal inlet was not lessened, but was maintained throughout, and gathers
in force in proportion to the additional rings attached. The velocity of the
air was at the rate of 728 feet per minute. Thus it is said to be possible, if an
adequate number of these machines are brought into requisition, to pass
upwards of 3,000,000 cubic feet of air through the mouth of a 20-feet shaft
in one minute.
Fig. 166 is a compressed-air ventilator adapted to tunnel headings, &c.
It is being worked successfully in the Cornish mines. With this single
machine, supplied with
a 1-inch pipe and four
jets with 60 lbs. pres-
sure, the largest blast
in a 7-feet heading
Fig. 166.
can be cleared in less than ten minutes. Where the utmost speed is
required, the smoke may be cleared instantaneously by having two or more
machines. The great advantage is that no delay is experienced after
the blasting, the men are enabled to resume work immediately in an atmo-
sphere freed of noxious gases: thus good ventilation can be effected at any
distance.
It will be evident that this ventilator involves an application of the
principles to which the late Sir Goldworthy Gurney first drew attention.
Gurney's "Steam Fet" was on some occasions used with much advantage in
collieries, especially for removing the products of combustion, and freeing a
colliery from the "after damp." For ventilation it was used under several
conditions. Mr. W. Teague's application possesses great merit and promises
many considerable advantages, especially from the rapidity with which it
clears close ends of the deleterious gases produced by the explosion of
gunpowder, of nitro-glycerine, of dynamite, or of any of the other explosive
compounds which have been recently introduced.
The Anemometer represented in the woodcut, Fig. 167, a useful instrument
for determining the rate at which the air travels
through the working of a mine, is of the pattern
usually known as Biram's-that celebrated col-
liery viewer having introduced the instrument
into the Earl of Fitzwilliam's collieries in
Yorkshire. It consists essentially of six vanes,
made of thin sheet brass; these are delicately
mounted on a centre moving freely within a
brass ring. It is carried by the handle, and
indicates the most gentle current, the rate at
which the vanes revolve being noted by the
index shown in the centre of the figure.
T
Immediately connected with the question
of the ventilation of metalliferous mines, there
arises the important one of freeing the work-
Fig. 167.
ings from the deleterious gases produced by
the explosive compounds used in blasting the rocks underground.
following list has been furnished by the "Explosives Committee," appointed
The
616
[BOOK III.
PRACTICAL MINING.
by the three Cornish societies* which give their especial attention to the
improvement of mining :-
A. GUNPOWDER.-Large grain (1), medium grain (2), small grain (3), compressed (4) :·
Charcoal
Sulphur
Nitre
A. GUNPOWDER.-Special strong (5).
B. ESPIR'S EXPLOSIVE POWDER:-
Nitrate of Soda
Sulphur
Hardwood Sawdust
15 per cent.
15
""
70 ""
Composition not stated.
60 per cent.
14
26
""
""
approximately.
}
approximately.
C. GUN-COTTON.-Pure cotton fibre which has been chemically acted on by strong acids.
D. TONITE.-Said to be gun-cotton, combined with nitrate of baryta.
E. TITANITE.-No information.
No. 1. Nitro-glycerine
F. DYNAMITE :—
Kieselguhrt
•
75 per cent.
25 ""
approximately.
No. 2. Contains less nitro-glycerine, together with varying proportions of charcoal and
a nitrate.
G. NO. 2. BLASTING GELATINE.-"Collodion cotton 7 to 10 parts, combined with thoroughly
purified nitro-glycerine 90 to 93 parts, at least 95 per cent. of the collodion cotton to be
soluble in ether and alcohol.”
H. LIVERPOOL COTTON POWDER.-Said to be gun-cotton combined with nitrate of potash.
I. PUDROLYTHE.
In answer to a number of questions circulated amongst the miners as to
the relative cost of these explosives, for doing an equal amount of work
under different conditions, the following replies were received :—
A. In wet ground
B. In very dry ground.
31 replies; Dynamite best 26, coarse Powder best 3, Tonite
best 2.
23 replies; Dynamite best 3, Powder best 10, fine Powder best 2,
large Powder best 2, medium Powder best 2, compressed
Powder best 2, Tonite best 2.
C. In loose or fissured ground 23 replies; Dynamite best 18, Powder best 2, Tonite best 2, large
D. In ends
E. In back stopes
F. In sinking
G. In open quarry work
•
Powder best 1.
29 replies; Dynamite best 13, Powder best 9, Tonite best 2,
Dynamite if wet or hard, Powder if dry or moderate 5.
18 replies; Dynamite best 7, Powder best 5, medium Powder
best 1, small Powder best I, compressed Powder best I,
Dynamite if wet or hard, Powder if dry or moderate 3.
23 replies; Dynamite best 14, Powder best 3, large Powder
best 2, small Powder best 1, Dynamite if wet or hard,
Powder if dry or moderate 3.
13 replies; Powder best 8, large Powder best 1, Dynamite best
2, Pudrolythe best 1, Dynamite where small stones are
required i. One reply said Dynamite is best under all
circumstances.
Another question related to the relative safety or danger in using these
different explosives. The replies to this query were very conflicting; the
majority considered dynamite to be safer in use than powder, but that it
required more care after use, i.e. in working the rock after it has been used.
One reply states, that the writer had used 2 tons of dynamite per annum,
for many years, without accident. Capt. Henry Eddy, of North Levant
mine, answers this question as follows: "Dynamite extremely dangerous.
Lithofracteur highly dangerous. Powder moderately dangerous." Captains
Jas. Vigus and Wm. Gribble say: "Tonite safest, dynamite next, Espir's
powder next, then gunpowder.”
The opinions of the miners being requested, as to the effects of the fumes
or the smoke upon the men after a shot underground, we find that all except
two agree that the fumes from dynamite are the most injurious. One of
*The Royal Cornwall Polytechnic Society, the Miners' Association of Cornwall and Devon, the
Mining Institute of Cornwall.
† Infusorial earth consisting of the silicious skeletons of microscopic organisms.
CHAP. III.]
EFFECTIVENESS OF EXPLOSIVES.
617
these, Capt. Abraham James, of South Frances mine, says: "The fumes from
dynamite are comparatively little when compared with powder, and with
ordinary caution men need not suffer much from dynamite. I believe
powder smoke in close places to be far more injurious.” Capt. R. H.
Williams, of Wheal Eliza, says: "We do not find dynamite injurious in
ventilated places. We find the resultant gases from blasting with it much
thinner and lighter than powder-smoke. We use dynamite almost exclu-
sively-not from compulsion-but from the choice of men and agents."
Most of the miners say that the fumes from powder are the least injurious,
but one says they are the worst. Other explosives are believed to be
intermediate in this respect.
Capt. Abraham James (of South Frances) says: "In this mine we use
nothing but dynamite, not because we think it more economical than
powder, but simply for want of good ventilation. The mine will be
thoroughly ventilated in a few days, we shall then insist on the men using
powder in many places where dynamite is used now. We consider we pay
equally as much now for drivage, as when no other explosive was used than
powder. The workmen prefer dynamite because, in the first place, it is a
little stronger, it requires no tamping, makes less smoke. It is a boon to
the workmen, but little or no profit to the adventurer. In my opinion
powder for ordinary ground is by far the cheapest explosive."
Sir Geo. M. Denys, Bart., of Richmond, Yorkshire, writes: "We have of
course tried various kinds of gun-cotton, powder, and tonite, but prefer
No. 2 dynamite to anything else, and use it almost entirely. In wet ground
it is invaluable, it requires no tamping. It is safer than powder or cotton.
In favourable places in roof or sole we can bore with a machine to a depth
of 6 or 8 feet, and charge accordingly, bringing enormous burdens. In orey
places, if not cautiously used, it smashes the rock, I think, overmuch."
Mr. Hort Huxham, M.I.C.E., writes: "For breaking up large masses of
cast-iron, 'horses' from the bottoms of the iron-smelting furnaces, and such-
like refractory material, gunpowder is practically non-effective, and the
desired effect can only be obtained with dynamite or nitro-glycerine. For
penetrating the very hard silicious 'Pennant' Sandstones and other hard
rocks of this district, especially when heavily watered, the greatest economy
and efficiency is arrived at when using a quick powerful explosive, such as
dynamite, with bore-holes of small diameter. For dealing with moderately
hard rocks and strong ground, other conditions, such as quantity of water,
thickness and inclination of the beds, fissures and joints, size of pit or
heading, ventilation, &c., would govern the economical and effective use
of the explosive. For shales and other soft ground the slower-acting
explosives, gunpowder-used with bore-holes of larger diameter-are much
superior to dynamite in effectiveness and economy, and for even the hardest
coal the latter explosive is useless. Practically, only gunpowder and
dynamite are used in this (South Wales) district.”
Mr. A. L. Stephenson, of Durham, says: "My opinion is that gunpowder
when used with safety-fuse, and supplied to the men in small cases or in
cartridges, is the safest, but if carelessly used, or carried loose, or in bags
as was frequently the case some years ago), I think it more liable to
618
[BOOK III.
PRACTICAL MINING.
accident than dynamite. If gunpowder be used in the form of a cartridge,
with safety-fuse attached, and carefully rammed with a copper rammer,
with dry clay or other like material, free from grit, there is, I believe, no safer
explosive in the market. Dynamite, on the contrary, should be used without
tamping of any description, other than water or fine dry sand, poured in loosely,
so as to avoid the danger of concussion from tamping with a rammer.
"In regard to boring holes after the use of dynamite, I heard of a case
where, in boring a fresh hole, an explosion took place with fatal results,
upon the boring chisel striking into a slight fissure in the Limestone rock, at
a depth of 2 feet, into which it is supposed some nitro-glycerine from dynamite
must have percolated from another hole that had been charged in its vicinity.
"The fumes of gunpowder are very readily dealt with by the ordinary
means of underground ventilation, and in no case have I ever seen or heard
of the densest fumes seriously affecting the men, but if the air is allowed to
be constantly loaded with them, and no sufficient ventilating current estab-
lished, then the constant inhalation prejudicially affects the men.
"When dynamite is properly exploded, the amount of noxious gases
given off is small, and by waiting a very short time the slight fumes are
carried off by the ventilating current. If, however, dynamite is not
thoroughly exploded, and partly or wholly burnt away, the resulting nitrous
gases are considerable in volume, and highly dangerous for the men to
breathe. Fatal results have from time to time arisen from this cause, by
the men returning before the fumes have cleared. In any unventilated
pit or drift, or other confined working place, I should consider it dangerous
for the men to return after an explosion of dynamite, without allowing a
considerable time to elapse."
These, the results obtained by practical miners from the actual use of the
various explosives named, are exceedingly valuable.
UNWATERING MINES.-In the drainage of mines the system of adits is
one requiring much attention. Although the great Gwennap adit, as it is
termed, through which the waters of numerous mines in Gwennap and near
Redruth are discharged, has been noticed, some additional particulars appear
necessary. It is, according to Mr. Thomas (who has carefully laid it down in
his map of the mining district from Chacewater to Camborne), about 26,000
fathoms, or nearly 30 miles in length, the various branches being included.
"The greatest length to which any branch appears to have been extended
from the adit mouth is at Carclew mine, measuring about 4,800 fathoms,
nearly 5 miles. The highest ground it has penetrated is at Wheal Hope,
where the adit is 70 fathoms deep at Chilcot's shaft, and is deeper in the
branches extending from thence." This adit is 39 feet above the level of the
sea at high water in Restronguet Creek, into which the waters discharged
from it flow, its mouth being near Nangiles, in a valley communicating with
the creek. The variable heights of other adits above the sea-level in the
same district are given in the following table, also by Mr. Thomas. These
form, in fact, the drainage system of one of the most important mining
districts in the United Kingdom :-
Carn Marth Cove Water-shoot.
Adit at Laity Mill
•
New Wheal Virgin Adit .
413 feet.
52 ""
374",
CHAP. III.]
DRAINAGE BY ADITS.
Peden-andrea, Redruth
Tresavean
Wheal Harmony
Wheal Mary
Wheal Sparnon, Redruth.
•
287 feet.
208 ""
171 ""
81 ""
315 ""
619
It becomes necessary in this place to examine the subject of the accumu-
lating of water in the mines. It is important to arrive at some general
knowledge of the quantity of water which is found in mines, and which has
to be pumped out of them. The only way of ascertaining this is, in the
first place to determine the quantity of rain falling on the surface, to
ascertain how much permeates the upper stratum, and the depth to which
it penetrates.
Dr. Dalton instituted in 1796-98 some observations on the proportion of
rain which penetrated to a depth of 3 feet in the earth. This absorbing
surface was 10 inches in diameter; for the first year it was bare, but covered
with grass for the last two years. The mean annual fall of rain was 33'55
inches, of which there penetrated to a depth of 3 feet, 8.41 inches. This
gives the rain falling on an acre as 121,484 cubic feet a year, of which the
absorption was 30,492 cubic feet, or an average daily absorption of 83 cubic
feet per acre, the quantity absorbed being about a fourth part of the rain
falling.* This of course represents the conditions prevailing at Manchester.
We are more especially concerned with the rain which falls on the surface in
our mining districts.
Mr. Thomas † estimated the drainage of the Fowey River in 1825 at about
160 feet per day from each acre of the country immediately upon its banks.
In 1826 it was only 75 cubic feet per day from each acre. He considers the
mean annual drainage to be about 43,800 cubic feet per acre, or 120 cubic
feet per day.
Mr. Davies Gilbert gives, from observations carried on over six years,
a mean of rainfall of 46 inches per annum, or 166,834 cubic feet per acre.
Mr. W. J. Henwood and others compute, "supposing all that is taken up
by the Earth flows out again in springs, the absorption by the surface will
be the 0'26 part, or about a quarter of the whole rain falling during the
year." Mr. Henwood carefully examined the Gwennap district, and deter-
mined the quantity of water falling in rain, and issuing from the rocks
and veins, at various depths. The district examined includes all the
mines which empty their waters into the great Gwennap adit, the various
ramifications of which extend between 30 and 40 miles on nearly the same
plane, and its extreme limits are about 5 miles from its mouth. In some
parts of its course it is not more than 12 or 15 fathoms deep, whilst in the
more elevated grounds to which the adit penetrates, it is 70 fathoms below
the surface. Throughout the district the average depth is probably from
35 to 45 fathoms.
Nine-tenths of this adit are excavated in Slate, the remainder being in
Granite, and in many cases it passes through Elvan courses. It intersects
almost every lode and cross vein in the Gwennap district. Mr. Henwood
limited his inquiry to the quantity of water flowing through the adit, and
derived from the various rocks, lodes, and cross veins, which it intersects,
*Memoirs of the Manchester Society," vol. v.
† "History of Falmouth," p. 50. Tratham: Falmouth.
620
[BOOK III.
PRACTICAL MINING.
and to that drawn from greater depths and discharged into it by the steam-
engines on the mines which it unwaters. Mr. Henwood says: "I have
calculated the quantity of water thus intercepted, and raised, which flowed
through the adit, and estimating that each bushel (84 lbs.) of coal
consumed by the steam-engines will raise 50,000,000 lbs. of water 1 foot high
(about the average duty of Cornish pumping-engines at the time the observa-
tions were made), the additional steam power which would be necessary
to raise the whole of the water to the surface would require an annual
increase of nearly 24,000 tons. The adit, therefore, effects a saving of about
£19,000 a year in the mines which it unwaters for fuel alone."
The following table was constructed by this indefatigable observer from
the following sources :—
1. "The Returns of Rainfall," published by the Royal Institution of
Cornwall.
2. Mr. Daniell's Tables, published in the "Meteorological Essays.'
3. Mr. Thomas's Observations on Carnon Stream, from his "History of
Falmouth."
4. Lean's "Engine Reports."
5. "Meteorological Report of the Royal Institution of Cornwall.”
Date.
1839.
Rain.
Cubic Feet per
Minute.
Surface Water.
Cubic Feet
per Minute.
Evaporation.
Cubic Feet per
Minute.
Water
Discharged by
Great Adit.
Cubic Feet per
Minute.
Water Drawn
from a Depth of
190 to 200 fathms.
Cubic Feet per
Minute
January
February
March.
•
•
•
April
May
June
July
August
September
October
November
December
January
1840.
1354'
40'
•
1559°
1711.
1365.
1245'
1958.
2382.
1072.
2551.
:
1570
3346.
3955'
| | | |
118
180°
1460.
881.t
119°
134°
1675°
979*
357°
552.
506.
[1
662.
1022*
850°
610.
885.
831.
328.*
1177°
709.
166•*
56.*
1064*
930'
42.*
1978.
946.
2898.
February
March
2545°
1786.
92.
I
104*
1119
1933'
119*
295*
{
2149°
1994*
1145. §
April.
352°
283°
1174
102I'
Mean of Year 1839
2005'
40*
309*
1323°
875°
From April, 1839, to
May, 1840
1904'
I
310'
1627.
944*
Mean.
•
1954*
40.
310'
1475°
909*
* Interpolated from the temperatures of these months in 1839, and the differences between the wet
and dry bulb thermometers for corresponding months in 1840.
+ This observation was made on the morning of the 1st January, and as the water flowing had been
pumped out of the mines in the preceding month, the quantity is from Messrs. Lean's December report.
These observations were made on the 1st and 27th January, and this amount is a mean of Messrs.
Lean's quantities for December and January.
§ These experiments were made on the 9th and 27th of March; this result is therefore from Messrs.
Lean's March report.
CHAP. III.]
AVERAGE ANNUAL RAINFALL.
621
The foregoing table shows that the quantity of rain which fell on this
track, during the period of inquiry, exceeded by about o'66 part the united
sums of the evaporation and streams flowing from the surface and adit. The
rain is, therefore, fully adequate to the supply of all the springs in the
district, whether their waters issue at the surface, or underground in the
mines.
It has been pre-supposed that the Earth was in the same state of
humidity at the beginning and end of the inquiries, but, as the rain
requires some time to descend into the mines, the water pumped out of
them cannot have been the same as fell at the time.
The average fall of rain during the period under consideration was 51°12 inches.
The average annual evaporation
8.1
""
or 15.83 per cent.
The average annual water flowing from the surface
The average annual water discharged by the adit
The difference, unaccounted for.
1.04
""
or 2.03
""
38.58
3°4
""
or 75°42
""
or 6·65
51.12
100
The following table, giving the rain for 1882 in Cornwall and the Scilly
Islands, is a necessary appendage to the statements given, as it shows the
rainfall of this recent period, and does not differ much from the remoter one.
Number of
Rainy Days.
Bodmin
Truro
Falmouth
Helston
•
Scilly
Means
Rain in
Inches.
62.03
243
48.10
•
224
·
60'25
247
49'77
256
39.10
289
51.85
•
241
THE MEAN MONTHLY AND ANNUAL FALL OF RAIN IN CORNWALL FOR FIFTEEN YEARS-
1866 TO 1880.
Month.
Penzance. St. Austell. New-Quay. Liskeard.
Saltash.
Bodmin. Launceston.
January
February
March
April
May
June
July
August
•
Inches.
+5.78
Inches.
Inches.
Inches.
Inches.
Inches.
Inches.
6.08
4.29
+6·41
+6·99
+6·45
+7.92
4'10
4.26
3.25
4.54
4.84
4.72
5.96
•
3.06
3.22
2.51
3.47
3'43
3.35
4.14
2.79
3*16
2.12
3.39
3.50
3.19
3.76
•
2.15
2.84
-I.99
3:00
-2.88
2.99
3.29
-2.03
-2.78
2'04
-2.69
2.95
-2.61
-2.87
2.67
3:07
2.38
3.57
3.75
3.21
3.99
•
3·18
3.91
2.99
4.29
4'04
4.15
5.16
3.83
4'90
3.92
5.65
5'44
5.24
6.27
5.12
5.30
4.16
5.84
5'49
6.05
7.35
4'93
5:00
3.64
4.76
4.84
5.06
5.82
5.42
+5°38
+4°35
5·06
5.72
5.73
7.15
45'06
49.90
37.64 52.27
58.87
52.75
63.68
September
October
November
December
Total
Sixteen values obtained by Mr. G. J. Symons give the mean at 49 inches.
There is but little doubt the 50 inches represent the average of the whole
county of Cornwall, which is twice the fall of rain in the Metropolis.
The proportion absorbed by the surface and penetrating to a mean depth
of at least 35 fathoms (a very considerable part of it to much greater
622
[BOOK III.
PRACTICAL MINING.
depths) is 75 per cent. The rate at which rain water penetrates into the
mines has been carefully investigated by Mr. W. J. Henwood. The results
obtained by him show that when the surface waters have been carefully
intercepted, by filling up pools, and plastering them with a tenacious clay,
and by constructing small channels to aid the general drainage, the mines
have been worked to a much greater depth with less powerful and less costly
engines. It has been shown, by ascertaining the quantity of rain which has
fallen, and of the water pumped from the mines, that the ratio of rain has
been 18.19; and the means of thirteen mines, on which observations have.
been made for seven years, 13'95, which sums bear to each other the pro-
portion of 0.766 to unity.
<<
Although in many mines most of the water finds its way to the deepest
level, yet the shallower levels, as they are worked for a longer time, and
usually extend further than the deep ones, often intercept a considerable
quantity. To avoid as much as possible the heavy cost of pumping from
great depths, the water in the shallower levels is at once conducted to the
pumps. On this account the upper lifts of the pumps are almost, without
exception, longer than the lower ones. But it may be presumed that the
water thus naturally collected at each series (lifts) of pumps does not always,
or indeed commonly, supply neither more nor less than the exact quantity
required to fill the pumps. Whilst the water is in excess at one level, and
for its drainage the pump should be worked rapidly, at others it is often
insufficient. When there is such a deficiency, an artificial supply is allowed
to descend to keep the pumps always filled (solid) lest the buckets, valves
(clacks), &c., should be injured by the irregular action of the engine and
other apparatus (going into fork)" (Henwood).
The same authority remarks: "If a perpendicular shaft were sunk in a
rock perfectly homogeneous and destitute of lamination, joints, or veins, the
portion drained by it would be an inverted cone, of which the bottom of the
shaft would be the apex and the surface of the Earth the base. The diameter
of this base would depend on the facility which the rock afforded for the
descent of water. The dimensions of this cone would vary with the depth of
the shaft, and consequently, if the water were solely derived from that sur-
face, there would be a very simple relation between that depth and the
quantity of water collected."
Mr. Thomas, in his report, remarks that the western part of Wheal
Friendship is often drained to more than 40 fathoms under the adit, whilst
the United mines, at a distance of about 600 fathoms, are worked at 160
fathoms below the adit, on the same lodes. "Hence it appears that the
surface of the water circulating through these lodes has an inclination of
about 12 degrees. If this should be taken as an average inclination in a dry
season, where water circulates without interruption through the lodes, it
shows that for every fathom in depth, the lodes will be drained to the
distance of five fathoms at the surface, and the quantity of water at the same
lode will increase in proportion to the square of the depth. In the wet
season the inclination of the water line will of course be greater, from the
quantity of moisture constantly supplying the Earth.”
It has been conclusively determined that there exists a close relation
CHAP. III.]
same.
WATER PUMPED FROM THE MINES.
623
between the water in the mines and that pumped from them, and the quantity
of rain which has fallen in the district in which they are situated. The
intervals between the maxima and minima in the different mines are not the
The column of rain always shows the proportion which fell just as
many months before as would be required for its descent; which rain, there-
fore, must be considered the same water which is afterwards pumped out of
the mines. In nature, the conditions to be investigated are complicated.
Our rocks are often schistose; the structure of even the most regular is far
from uniform; whilst all of them are traversed by joints and veins, and the
mineral composition is liable to some variation at almost every fathom.
Some of these circumstances impede the drainage whilst others facilitate it
at almost incredible distances.*
Messrs. Lean have given a table † from which we obtain a very correct
idea of the proportionate quantities of water pumped from the mines in
different rocks. They state the maxima and minima quantities in cubic feet
per minute, from forty mines during five years as follows:-
Maxima.
Minima.
Years.
Granite.
Slate.
Granite.
Slate.
1833
35.
164°
19'
1834
35*
140'
15°
1835
24.
88.
14.
1836
28.
107.
16.
68.
1837
28.
110.
17'
Means
30'
I22.
16.
888
89'
60.
58.
66.
68.
The proportion between the means of the maxima and the means of the
minima appear to be nearly the same, and they agree in showing that the
quantity of water yielded by the mines in Slate is about four times as much
as by those in Granite. The water drawn from the Greenstone rocks is much
less than either.
We have no reliable record of the quantity of water pumped from the
mines in the Limestone and other rocks of Derbyshire, Yorkshire, or those of
the northern counties. In most of the lead mines the quantity of water is
very large, and we know that it bears a close relation to the quantities of
rain which falls upon the surface. Much of it is discharged by the adits,
but in many of the lead-mining districts—that of Mold in Denbighshire may
be quoted in illustration-valuable lead mines have been abandoned, the
flow of water being beyond the power of the largest steam pumping-engines.
The greatest quantity of water found in mines is derived from the surface,
and it is discovered by experience that, by carefully guarding the surface by
an efficient system of drainage—by either preparing channels to carry off the
rain-water, or by constructing reservoirs for preserving it—a great economy
is effected. The water of course penetrates the earth at different rates and
* Those who may desire to pursue this inquiry should consult Mr. W. J. Henwood's Memoir "On the
Quantity of Water in the Cornish Mines," in vol. v. of the "Transactions of the Royal Geological Society
of Cornwall."
+ "Historical Statement of the Improvements in Cornish Steam Engines." By Messrs. Lean.
624
[BOOK III.
PRACTICAL MINING.
in varying quantities according to the nature of the stratum through which it
has to percolate. All the fissures, including the mineral veins, form channels
through which the waters falling as rain rapidly pass away. In addition
to these channels the rocks themselves form vast filtering beds through
which aqueous fluids are constantly percolating. The hot springs, to which
attention has been already directed, ascend from profound depths; but even
those derive their waters from the surface of the land, or from the vast ocean.
The circulation of waters is a curious and complex study with which we have
not now to deal. It appears necessary to thoroughly receive the idea that
the waters which fall on the Earth's surface, and which are so essential to the
whole vegetable world and to the animal economy, are derived by evapora-
tion from the "Earth-girdling sea," and are held in suspension as vapour in
the atmosphere, forming clouds in all their various conditions, until, by
changes of temperature, the saturated air parts with its water in the forms of
dew, mist, rain, hail, or snow. As in one of these states the water falls and
passes through the fissures, veins, and strata, and penetrates the earth, it
eventually arrives at such a depth that it becomes heated and acquires a
strong ascensional force, showing itself in this country in hot springs and in
other places in the condition of steam.
In 1811 Mr. Joel Lean commenced the publication of his "Engine
Reporter," the intention of which was to record the actual work done by
the pumping-engines. At first there was much prejudice amongst the
engineers, and the mine agents, so that but few of the engines were noticed.
The value of the record was eventually admitted, and a large number of
engines were included. The following table shows the steady increase of
duty to 1856:-
Year.
Approximate
Number of En-
gines reported.
Average Duty
of the whole.
Average Duty of
the best Engine.
1813
24
19,456,000
1823
45
23,156,162
26,400,000
42,122,000
1833
1838
1843
174
503
57
46,142,406
83,306,100
61
48,700,000
84,200,000
36
60,000,000
96,100,000
1848
27
53,166,600
1856
24
47,000,000
In 1838 the Messrs. Lean reported the average duty of 61 pumping-
engines as amounting to 48,700,000 of water 1 foot high by the consumption
of a bushel (94 lbs.) of coal; and in the year 1856 Mr. Thomas Lean
reported 24 engines as having consumed 19,578 tons of coal, which raised
160,000,000 tons of water 10 fathoms high, being 56,000,000 lifted I foot
high by 112 lbs. of coal, or 47,000,000 lbs. raised throughout the same space.
by the consumption of 94 lbs. of coal, showing a decrease 18 years later of
1,700,000 lbs. per bushel. A similar report was published by the late
Mr. Browne, of St. Austell, which included 22 pumping-engines in 1856,
giving an average duty of 35 millions of pounds raised 1 foot high by the
consumption of 112 lbs. of coal.
The following table will show the principle upon which Lean's "Steam
625
CHAP. III.]
THE DUTY OF STEAM PUMPING-ENGINES.
Engine Reporter" was constructed, and it gives a correct statement of the
variations in the amount of work done by the steam-engines constructed for
draining the waters from the deep mines of Cornwall. The term "Duty,"
which is used here, was first employed by James Watt to signify the nett
effect resulting from the consumption of a given weight of coal. The
expression may be regarded as the term which signifies the amount of force
employed and the weight of water lifted, multiplied by the space through
which it acts, divided by the weight of coal consumed :-
TABLE SHOWING THE DUTY (WORK PERFORMED) BY SOME OF THE BEST CORNISH PUMPING
ENGINES DURING THE PAST FORTY YEARS.
(From Lean's "Engine Reporter.")
Year.
Mines.
Engines and Dia-
meter of Cylinder.
1840 Wheal Darlington
Wheal Vor .
Fowey Consols
1845 Wheal Vor
Dolcoath
Great Work
1850 United Mines
South Wheal Frances
Dolcoath
1855 Great Work
•
Wheal Tremayne .
South Wheal Frances
1860
Alfred Consols
1865
West Wheal Seaton
Cargoll
Wheal Seton
Load on Piston per
Square Inch.
Actual Horse-
power employed.
Number of Strokes
per Minute.
Horse-power per
Coal consumed per
Hour.
Foot high by con-
Pounds 'raised One
suming 112 lbs. of
Coal.
of Water drawn
Average quantity
per Minute.
·
•
Leeds
Inches.
Lbs.
Eastern 80 15.11
Trelawny's 80 15.25
Austen's 80 11.65
Trelawny's 80 15.90
Jeffrei's
76 12.10
60 14.50
Lbs.
Millions.
Imp. Gals.
8.55
8.16
7.20
7.10
3'5
| |
5'90
4.4
7.40 3.2
By 1 bushel coal,
94
lbs.
84.0
842
59.2
409
85.2
547
53.I
962
41.5
280
56.9
176
Taylor's 85 15.60
•
Tredinnick's 75 ΙΟ ΙΟ
Hocking 76 12.50
Leeds
Michell's 60 13.00
Marriot's 75 14'50
Davey's 80 9.70
Harvey's 85 7.70
Sandy's 70 15.40
Tilly's
Elliot's
50 14.20
Harvey's 85 22.30
Tegoning's 70 7:00
Harvey's 85 12.30
Trevenson's 80 15.10
Willyam's 70 1140
Harvey's 85 17.40
Thomas's 60 16.80
221
92
7.50
2.4
90'0
1
6.30
ΙΟΙ
6.50
2 5
2.9
76'0
491
5.0
43.0
308
60 14.70
87
7.70
3.2
69.0
297
59
5.30 3.I
71.0
402
60 2.80 3.6
60.0
218
87
5'90 2.6
82.6
522
70 4.50 3'9
55.7
292
ΙΟΙ 5.80 3'9
56.0
492
70 | 10-30
39 3°30 3.I
70.0
89
35 4.20 3.3
65.6
135
176 4.60 3.6
61.6
506
40 4.50 3.2
69.1
258
90 3.60 3°3
66.6
234
73 3.30 3.9
56.6
234
85 6.60 3°3
65.5
60г
224 6.80 3.5
63·2
902
104 8.40 3.5
62.3
383
64.0 391
∞
96 4.50 3.5
81 3.10 4.2
62.7
168
52.2
380
West Caradon
Great Wheal Busy United
1870 Wheal Seton
West Wheal Seton
North Wheal Crofty
1875 Crenver and Wheal Abraham
West Wheal Seton
West Basset.
1880 West Wheal Seton
Dolcoath
Mellanear
Harvey's 85 13.80 128 4·60 3°4
85 13.80
Gundry's 80 17.20
Loam
The application of the expansive power of steam, and its introduction
to the mining world, has been already noticed in the historical sketch given.
Hornblower, however, in 1781 invented the double-heat valve, and took out
a patent for working steam expansively. This engineer was also the first
who employed two cylinders, his engine being since known as the "Combined
cylinder engine." The steam was admitted so as to elevate or depress the
piston in the first or smaller cylinder, and then allowed to act by its
expansion on the larger piston in the second cylinder. The steam employed
by Watt was, as it is termed, low-pressure expansive. In 1802 Trevithick
and Vivian patented their application of high-pressure principles to the
steam-engine. In the notice already referred to, the two Trevithicks, father
626
[BOOK III
PRACTICAL MINING.
and son, are mentioned, and about that time we have the first satisfactory
notice of the engineering capabilities of Richard Trevithick, jun. The
following account informs us that Trevithick had erected a steam-engine
at Wheal Treasury, when he was brought into direct competition with
James Watt and Edward Bull:-
WHEAL TREASURY COST, JUNE, 1795.
Richard Trevithick, jun., 13 days at
•
Richard Trevithick, sen., for expenses at Helston at sundry times, and at
other places, waiting on the Adventurers
Richard Trevithick, jun., for moving and erecting the eastern engine
Ditto for one month's attendance on ditto
To Edward Bull for his attendance
To Mr. Bull's engine, for two months' saving respecting his engine
1796, APRIL.
£ s. d.
0 3 6
O
7 6
21
O O
18
2 2
43 12
The said Richard Moyle subjects himself to pay any demands which may be hereafter
made by Messrs. Boulton and Watt for savings in the same mine.
At a meeting of the Old Adventurers of Wheal Treasury, held this 27th day of
March, 1797, at Praze-an-Deeble, it was unanimously resolved that the earnings claimed
by Boulton and Watt should not be paid till the validity of their patent should be fully
proved.
The elder Trevithick, who has been already mentioned, was an active
agent in resisting Watt's patent claims upon the Cornish mines. In August,
1797, "Trevithick's hand was cold, but he had lived to see his son an
engineer, competing with Watt. This was a dark time for Cornwall-death,
law proceedings, and poverty were rife, and the numerous prosperous mines
of twenty years before had dwindled down to bare walls and barren mine-
heaps."*
The estimation in which the younger Trevithick was held is related as
follows by Captain Richard Eustace: "At Wheal Treasury one of Boulton
and Watt's pumping-engines worked badly, and at last stopped. The
engineman in charge could do nothing with her. The water was rising in
the mine, when Trevithick, jun., offered his services and made things. right.
His father boasted that the best man in the mine could not do what his boy
had done." In 1798 Trevithick was engineer at Herland mine, and was
engaged in a lawsuit with Boulton and Watt for infringement of patent,
Watt having placed one of his engines on that mine. In 1802 Bull, jun.,
and Trevithick erected a similar engine, whose cylinder was 60 inches in
diameter and placed directly over the shaft, the piston-rod being attached to
the pump-rods. Captain Grose stated just before his death, in 1858, that
Trevithick was, in 1800, "the head engineer in the county."
In 1800 the younger Trevithick constructed his globular tubular boiler,
and in 1811 his cylindrical boiler for Dolcoath engine.† Lean tells us that in
1801 in Crenver and Oatfields, in the parish of Crowan, Trevithick found
the pit-work to consist of leathern buckets, with two or three pistons, such as
were at that time in general use for plungers, in a very bad state; and it
may be safely asserted that the engines were idle at least one-third of the
time, repairing the pit-work and changing the buckets. Here Trevithick
* In the revival of mining, Richard Trevithick the younger took an active part. He strove to con-
struct pumping-engines which should not be liable to Watt's patent claims, and he was successful in
doing so.
Lean's "Historical Statement of Steam Engines in Cornwall." 1839.
CHAP. III.]
RICHARD TREVITHICK'S ENGINES.
627
first introduced his plunger-pole, instead of the common box and piston,
wherever he found it practicable.
In 1798 Trevithick erected the water-pressure engine at Roskear mine.
Captain Joseph Vivian, the manager of this mine in 1815, says "he re-erected
the old water-pressure engine, which was then spoken of, as the first water-
pressure engine ever erected with a pole and side-rods." Wheal Druid
copper mine appears to have been the first at which Trevithick overcame
the difficulties of using water instead of steam. Here he worked at a
pressure of 100 lbs. to the square inch.
Gregory says: "Some further attempts to make pressure engines upon
the principle of the steam-engine have failed, because the water, not being
elastic, could not be made to carry the piston onwards a little, so as com-
pletely to shut one set of valves and open another. In the present (Trevi-
thick's) judicious construction, the tumbler performs the office of the
expansive force of steam at the end of the stroke."
In 1802 Trevithick erected a water-pressure engine at Hill Carr Sough,
near Youlgreave, which appears to have worked for fifty years, when it was,
with several others, sold.
Up to 1800, minerals had been raised by horse-whims from the Cornish
mines, in buckets, barrels, or kibbles made of wood and bound with iron.
When steam-whims were introduced the breakage of those was greatly
increased. This led Trevithick to introduce the wrought-iron kibbles,
shaped like an egg with flattened top and bottom, and he also invented a
new method for emptying them.
"The new iron kibbals were two or three times as large as the old ones
for the horse-whim. The poppet heads were raised that the kibbal might
go higher. The landing man said, 'I wonder who is going to land them
big kibbals; I shan't land them.' Capt. Trevithick said, 'Can't you wait a
bit?' When it was all complete the kibbal didn't want any landing. It
turned upside down, and the stuff went into the waggon without any landing
or shovelling." †
The new method was to carry the loaded kibble a certain distance above
the waggon; a chain from one side and pincers were attached to a hook in
the kibble bottom; the loaded kibble was then lowered the required
distance, the fixed chain drawing the kibble off the line of the shaft and over
the waggon, and at the same time turning it bottom upwards, discharged
its contents into the waggon; then a pull on a catch freed the pincers, and
the kibble dropped over the line of the shaft ready for descending. This
method, introduced in 1800, is still in use, though square boxes of iron on
wheels, sliding in guide-rods in the shaft, are now preferred.
+
With Trevithick's share in the introduction of the steam-engine on tram-
roads in Wales in 1803 and at Newcastle in 1804 we have nothing to do in
this volume. Rees, in his "Cyclopædia," in 1819, says: "We have an
account of a trial of a small high-pressure engine, made in Wales in 1804,
to ascertain its powers to raise water. The cylinder was 8 inches in diameter
+
* Gregory's "Mechanics," 1806.
"Life of Richard Trevithick." By Francis Trevithick, C.E.
"Life of Richard Trevithick, with an Account of his Inventions." By Francis Trevithick, C.E. 1872.
SS
628
[BOOK III.
PRACTICAL MINING.
and 4 feet stroke. It worked a pump of 18 inches in diameter (about 4
feet stroke), which raised water 28 feet high. It worked at the rate of 18
strokes per
minute and consumed about 80 lbs. of coal per hour. This when
reduced is about 17 million pounds raised 1 foot high for each bushel of
coals."
R. Trevithick, Andrew Vivian, and William West were partners in the
patent of 1802 for Trevithick's high-pressure engine. In 1807 the accounts
show that the patent premiums received more than covered the expenses.
Hyde Clarke, who knew Trevithick, and whose father was intimate with
him, wrote: "The introduction of Trevithick's improvement gave increased
power to steam, and it is of that importance that Stuart * is inclined to date
the era of the steam-engine, from Trevithick's introduction of high-pressure
engines. In the establishment of the locomotive, and in increasing the
capabilities of the marine engine, there can be no doubt that Trevithick's
exertions have given a far wider range to the dominion of the steam-engine
than even the great and masterly improvements of James Watt effected in
his day." +
Arthur Woolf was born in 1766,‡ and served an apprenticeship to
a carpenter and joiner, in the village of Pool, near Camborne. The sub-
stantial benefits conferred by Woolf on his native county require some
notice of his labours. He obtained employment as a first-class man in the
engineering shop of Bramah at Pimlico. In 1795 Woolf left Bramah's shop
to start on his own account. In 1796 he was employed to erect a second-
hand Boulton and Watt engine at Newbottle colliery in Durham, which he
promised to improve, so that it should consume less coal. This promise he is
said to have successfully carried out. Woolf returned to London, and was
called in by Messrs. Meux and Company, brewers in London, to assist
Hornblower in getting over a difficulty with his patent two-cylinder engine.
Being successful, Arthur Woolf was appointed resident engineer to the
brewery—receiving at first £2 a week and subsequently £3-which situation
he filled until 1806, when he established a steam-engine factory of his own.
Woolf applied high-pressure steam and Watt's condenser to Hornblower's
two-cylinder engine, and in 1804 he patented this mode of working high-
pressure steam. On April 17th, 1811, certificates were published stating
that "Woolf's engine, with one bushel of coal, can lift from 30 to 40 millions
of pounds 1 foot high, but Boulton and Watt's engine of the same size only
from 12 to 13 millions of pounds 1 foot high." Woolf was the first to make
a wrought-iron boiler sufficiently tight for high-pressure steam in Cornwall :
up to 1817 Woolf had used only his patent cast-iron boiler, when, being
examined before a committee of the House of Commons in May of that
year, he was led to make some experiments on wrought-iron boilers, which
were very successful. §
I
I
Woolf selected one of the ablest boiler-makers in Cornwall to assist him,
"Historical and Descriptive Anecdotes of the Steam Engine." By R. Stuart.
Railway Prejudices and Railway Progress." By Hyde Clark, Esq.
+
"A Brief Sketch of the Life and Labours of Arthur Woolf, Engineer." By Samuel Hocking, C.E.
(The late Samuel Hocking was himself a high-class engineer, and erected several pumping-engines for
the water companies in London.)
§ See "Partington on the Steam Engine"; "Dodd on Steam Navigation"; Report of the
Committee of the House of Commons on Boiler Explosions, May, 1817.
CHAP. III.]
HORNBLOWER'S AND WOOLF'S VALVES.
629
and personally superintended the work. He saw that properly-shaped
cylindrical punches were used, that special care was taken in punching the
holes, and that all the rivets were made to a gauge of uniform size. Above
all, he insisted that no yarn should be used in the joints. Prejudice was
against him in this, and his boiler-maker protested that he could not make a
boiler tight without yarn. Arthur Woolf's experiment was a complete
success, and his boiler was a type for all high-pressure boilers made in
Cornwall. Mr. John Taylor wrote the following statement with regard to
Woolf: "He made many valuable alterations in the details (among which
may be mentioned the remodelling of Hornblower's double-beat valve into
the present improved form), introduced a style of manufacture greatly
superior to any that had before been known in the county, and formed in
fact a new school of engineering there. He seemed to possess an almost
inexhaustible mine of invention. His improvements in detail were almost
innumerable, for scarcely a single part of the engine could be named,
however apparently unimportant, which did not receive some beneficial
alteration at his hands. His talent for contriving tools was very great,
and he seemed to have almost an intuitive perception of the best method of
performing operations and processes of all kinds."*
A more appropriate place than this cannot be found for a short statement
of the several valves introduced in the Cornish steam-engines.
Hornblower's valve, Fig. 168, has been described in many publications. A
very good account of it will be found in "Gregory's Treatise on Mechanics,"
vol. ii. page 378.
Woolf, to render easy the handling of his large-sized engines, invented the
double-beat valve shown in Fig. 169, and first applied it to a 90-inch cylinder
B
A
B
d
Ꭺ
B
A
Fig. 168.-Hornblower's
Valve.
Fig. 169.-Woolf's Valve, Con-
solidated Mines Engine, 1823.
Fig. 170.-Woolf's Valve,
Wheal Alfred Mine Engine.
engine, which he erected at the Consolidated mines, in Gwennap, about the
year 1820. This valve answered its purpose very well, and continued in
action for many years; but was not repeated, for Mr. Woolf soon afterwards
changed its form to that shown in Fig. 170, which improved valve he first
applied to the Wheal Alfred engines about the year 1823; since which time
this form of valve has undergone no change, and is now known out of the
county as the Cornish double-beat valve.
* Contributed by Mr. John Taylor to Pole's Work on the Cornish Engine.
SS 2
630
[BOOK III.
PRACTICAL MINING.
The mode of working may be easily understood from an inspection of the
drawing, Fig. 170. 0 0 is a ring of gun metal, having an inclined face turned
upon its upper and inner face, as shown-this forms the lower "beat" of
the valve. From the interior of this ring spring the radial arms g g, which
meet at the centre of the valve in the boss b. At their upper edge they
unite in the concave plate s s, upon the outer edge of which is turned the
conical face, which forms the upper "beat" of the valve.
The boss b, with its ring o o, ribs gg, and its upper concave plate s s, is
cast in one piece, and held down in its place by means of the bolt c and
cross-bard, thus forming the "valve-seat."
The movable part or valve proper consists of a ring of metal v, with
turned surfaces at a a, á á joined by radial arms to the boss e, into which
the spill ƒ is fixed, is shown in the drawing as if closed, the turned surfaces
at a a and á á being in contact. In this position no steam can pass from
A to B, or vice versa, for all communication is shut off by the "beats" of the
valve itself—the plate s s at the top, and the ring v of the valve itself. When
the valve is lifted, the steam is at once able to pass in two ways-first,
directly through the opening á á at the lower "beat," and secondly, between
the radial arms of the valve-through the upper seating a a, thence between
the ribs of the valve-seat g g, to the opening below.
The lettering is the same, for similar parts, of all the three figures.
It is not the author's purpose to enter more closely into the question of
the Cornish pumping-engine than is necessary to convey a correct idea of
its main principles of action, and incidentally to direct attention to a few
names, which deserve high praise, for the thoughtful ingenuity which the men
who bore them gave to the improvement of the application of steam-power
to the drainage of our deep mines.
While on the subject of valves, a brief notice of two or three valves which
have been more used than any others in our mines may be given here.
For further information on this subject the reader is
referred to Mr. Stephen Michell's book on Mine
Drainage.*
The valve represented (Fig. 171) may be regarded
as a type of the clack-valves. The ordinary clack-
valves are hinged to the seat, with rivets or pins,
working in a recess or slot. These are used exten-
sively in the Cornish pump-lifts.
Mr. Teague originated a clack-valve with a series
of perforations, over which circular pieces of india-
rubber work. Valves on this principle, being noise-
Fig. 171.—Double-beat Valve. less, have given satisfaction, being considered an
improvement on the ordinary clack-valves. Valves
with a vertical lift are of various kinds, known as cap-valves, wing or mitre
valves, spill or mushroom valves, and ball-valves. Harvey and West's
double-beat valves are the best known of this variety. These valves have a
large lifting area, a spacious water-way, and consequently a low lift. Where
"Mine Drainage, being a Complete and Practical Treatise on Direct Acting Underground Steam
Pumping Machinery." By Stephen Michell. Crosby Lockwood & Co. 1881.

CHAP. III.]
VALVES FOR STEAM-ENGINES.
631
the water is free from grit these valves are the best, but the presence of
grit in the dirty water of the mines renders them objectionable in the
Cornish mines.
Fig. 172 represents Husband's four-beat valve, which is an extension
of the principle already named. "Some
of these engines (direct acting) used
for pumping water for the supply of
towns make an upstroke of 10 feet in a
second, with poles reaching a diameter
of 50 inches, and this valve allows the
water to pass with such freedom that
the valve is closed at the moment the
up-stroke is completed, and there is
consequently no loss of water, or any
shock. About sixteen years since
valves on this principle were used for
a pump for raising water from a depth
of 320 yards in one lift, at the Eagle
Bank colliery, Yorkshire, and they
acted without shock under that great
head of water, and are at work to the
present day."
*
B
Fig. 172.-Husband's Four-beat Valve.
Mr. James Simpson designed a valve formed of three rings, or annular
valves, the inner and outer edges of which have beats. Each valve is separate
and the lift is independent of the others. This is mainly used in engines
for waterworks.
We have spoken of the important improvements made by Woolf in the
steam-engine. Useful as these were, they were surpassed by the high-
pressure boilers which he introduced. Low-pressure boilers were made of
wrought iron, some of them had as many as 1,500 rivets, each of which,
says Mr. George Dodd,t "in some measure answered the purpose of a
safety-valve;" that is to say, they allowed high-pressure steam to escape.
The following remarks by Mr. James Sims are much to the purpose:-
"I commenced engineering in the year 1811, at a period when the steam-
engine was in a very rude state, and from that time to 1814 little or no
improvement in the mode of constructing the steam-engine took place, but
was carried on just as left by Boulton and Watt, and their active agent,
Mr. Murdock. The increase of duty was, therefore, only just as follows,
taking the three following years of 1812, 1813, 1814. Average duty in 1812
was 19.3 millions; 1813, 19.5 millions; 1814, 20.6 millions. In the latter
part of 1814 Mr. Arthur Woolf erected one of his patent combined cylinder
engines, and with great success, when compared with those of Boulton and
Watt. The duty of Woolf's engine having risen to 523 million pounds,
lifted one foot high by the consumption of one bushel of coal, and he having
improved several Boulton and Watt engines, by causing them to work
* "Pumping Machinery." By W. Husband, C.E. ("Proceedings of the Mining Institute of
Cornwall," vol. i. No. 5, page 167.)
† Report of Committee of House of Commons on Boiler Explosions, May, 1817.
"History of the Cornish Engine" (Mining Almanack, 1849).
632
[BOOK III.
PRACTICAL MINING.
more expansively by using higher steam, awakened the whole of the Cornish
engineers to a new era in steam power; and many a sleepless night have I
had with others, in repairing the many breakages of engines and boilers, caused
by the boilers being too weak for the steam attempted to be used, and the
materials of the engine not being strong enough for the concussion given,
by the sudden admission of much higher steam on the piston than was
originally intended."
Early in 1815 Woolf was employed by the managers of Dolcoath mine
to report on the efficiency of the steam-boilers belonging to their large
engine, as there was difficulty in raising steam from them to meet the
requirements of the engine, which was getting more heavily loaded as the
mine deepened. He found the boilers of ample capacity, and coal enough
consumed to give the necessary quantity of steam; and the fact of their
not doing so was proof to him that much of the heat was escaping to the
chimney, which, on examination, he found was the fact.
He simply
removed the outlet passage to the chimney from the highest part of the flue
to the lowest, when it was found the steam-giving power of the boilers, under
the altered condition, had so increased, as to render it unnecessary to add
the contemplated new boiler. This simple alteration placed the pumping
power of the mine in a condition that so greatly pleased the Adventurers
that they not only paid Woolf handsomely for his professional services,*
but advanced also the wages of their engineers on the mine, Jeffery and
Gribble, who had but recently been appointed. Richard Jeffery, as a
young man, had been working with the engineers in Dolcoath mine for
some years; James Gribble was an engineman at Stray Park mine, from
which situation he was removed to join R. Jeffery, as engineer of Dolcoath
mine, in June, 1812.
Woolf, on his inspection of the. machinery, &c., at Dolcoath in the
year 1815, was much pleased with Gribble, and often said he was the most
promising young man for his profession he had met with in Cornwall.
He was ever afterwards his personal friend and adviser on all engineering
questions.
Dolcoath new engine, erected by Jeffery and Gribble in 1816, has often
been referred to, to show how near other engineers, using single cylinders
(Boulton and Watt form), approached the duty done by Woolf's two-cylinder
engines. The facts are as follows:-
"Soon after the time of Woolf's inspection, early in the year 1815,
Dolcoath Adventurers, finding it necessary to provide for the further
deepening of the mine, decided on erecting a new and more powerful
engine, and intrusted its construction to their own engineers, Jeffery and
Gribble. Gribble, being the ablest man of the two, had the most to do with
preparing the drawings for the construction of the several parts of the
said engine, some of which were made at Neath Abbey, some at Perran
Foundry, and most of the wrought ironwork was forged and fitted on the
mine. Every drawing was submitted by Gribble to his friend Arthur Woolf
for his correction and approval before it was issued as orders to the different
factories, &c., where the piece was made.”
*The Mine Cost Book for March, 1815, shows that Woolf was paid for his professional services.
CHAP. III.]
WILLIAM WEST'S ENGINES.
633
The success, therefore, of the Dolcoath engine, erected by Jeffery and
Gribble in 1816, was mainly due to the fact of its having been constructed
under the supervision of Mr. Woolf, and in accordance with his patent of
1804, wherein is specified how high-pressure steam may be safely employed
in engines of Boulton and Watt's construction, "by making all the parts
stronger, and properly proportioning the valve that admits the steam from
the boiler on to the piston."
A portion of his specifications reads as follows:-
"With regard to steam-engines in which the separate steam measure
(referred to in 4th clause) may not be thought advisable, the same may
be improved by the application of my aforesaid discovery, by making
the boiler and steam case in which the cylinder is enclosed much stronger
than usual, and by altering its structure and dimensions of the valve
admitting steam from the boiler into the cylinder, in such a manner as
that the steam may be admitted very gradually at first, afterwards more
freely. The reason for this precaution is this,-steam of such great elastic
force as I employ, if admitted suddenly into the cylinder, would strike with
a force that would endanger the safety and durability of the engine. Due
and effectual means must be used to keep up the requisite temperature of all
the parts of the apparatus into which the steam is admitted, not intended to
be condensed."
The name of West has been mentioned more than once in these pages.
As a self-educated man, who placed himself in the first rank of Cornish
engineers, some brief notice of him, and of his works, is required.
It is an interesting link between Trevithick and William West, that the
latter well remembered holding a candle to the great Cornish engineer, while
the "Catch-me-who-can" was in process of construction.*
Mr. F. Trevithick, in the "Life of Richard Trevithick," says the three
Wests, all skilful mechanical engineers, were employed at Dolcoath in 1816.
These were workmen, when Jeffery and Gribble erected their 76-inch engine,
fitted with a double-beat valve. When about sixteen or seventeen William
West was employed by his brother-in-law, and subsequently he was engaged
by Captain Joseph Vivian as working engineer, in erecting a pumping-engine
at North Roskear. This engagement led him frequently to Hayle Foundry,
and his abilities attracted the attention of a member of that firm, who
introduced him to the Messrs. Bolitho, of Penzance, for whom he erected an
engine to drive a flour-mill. William West was next engaged as working
engineer by Captain Nicholas Vivian, and employed in charge of two
pumping-engines of 80-inch cylinder, erected in 1827 by Captain Grose.
William West in 1831 entered the employment of Mr. J. F. Austen (after-
wards Trefry) as engineer of Fowey Consols and Lanescot mines. In 1834
52 engines reported an average duty of 47.8 millions, the average duty of the
best engines this year being 90'9 millions. This shows how greatly the
engineers named had improved the Cornish pumping-engine.
"Mr. William West erected a new 80-inch cylinder engine at Fowey
Consols mine, in constructing which he had availed himself of all the
improvements that had been made for some years; and as he had filled the
* The name of Trevithick's locomotive, which was worked near Euston Square in 1808.
634
[BOOK III.
PRACTICAL MINING.
situation of deputy engineer at Wheal Towan at the time when Captain
Grose was so successfully carrying out his views on the subject, he was
enabled to construct a machine which exceeded any hitherto known.
Austen's engine was reported for the first time in July, 1838. Its average
duty for that month was 90 millions, and for the following September
97,856,382." *
An experimental trial of Austen's steam-engine, of 80-inch cylinder, at
the Fowey Consols mine, which was conducted with the utmost care, shows
that this machine gave the extraordinary duty of 125,000,000.†
In addition to several other mechanical appliances of great excellence,
the boilers of West and Petherick excited much attention. The judges of
the Polytechnic Society+ say: "The principal improvement in the construction
of these boilers consists in their having a horizontal cylindrical tube enclosed
within the tube which contains the fire. The water is supplied from the feed-
pump to the inner tube around which the fire is arranged, and the steam
and heated air pass from it to the boiler, and from thence to the steam-
pipe."
Mr. West erected, in 1835, a steam-capstan on South Hue mine, the first
of its kind ever put up. This excellent Cornish engineer was next employed
to erect engines for the East London Waterworks, for which he devised a
double-beat valve, and he also patented some improvements in valves, the
chief advantages of which were-facility of adaptation to the degree of
sure; readiness of renewal; simplicity of construction and form; easy and
equal action; adaptability to any position; and cheapness as the result of
this simplicity.
pres-
In connection with Mr. John Darlington, Mr. W. West in 1867 patented
a system for counterbalancing pumping-rods, changing the angles of recipro-
catory motion and transferring power.
In conducting mining operations at any considerable depth below the
day level, it is frequently necessary to counterbalance the pump-rods by
means of levers or "balance bobs" placed at the surface of the ground, or
in cavities excavated horizontally out of the side of the shaft.
Although a weighted lever has been employed for this purpose since the
year 1770, yet its use is open to some objection, inasmuch as the action of
the counterpoise is never strictly in the line of pumping motion, and the space
required underground is only obtainable at a great expense.
When a vertical shaft has struck the lode, and it is designed to continue
the sinking upon the lode itself, the pumping motion is transferred to oblique
rods by a simple joint and bar or "fend off," or by means of a bell-crank or
V-bob-arrangements not only causing much friction, but expensive and
troublesome to keep in order.
Sometimes it is desirable to work pumps in two or more shafts by the
same engine. The motion is then communicated from one shaft to the other
by horizontal or flat rods supported on rollers, the direction of the motion
being changed by bell-cranks as in the former case. This arrangement
* Lean's "Historical Statement of the Steam Engine in Cornwall," 1839.
See a description of this engine in the "Transactions of the Institution of Civil Engineers,” vol. i.
1836; and De la Beche's Report on Cornwall, Devon, and West Somerset.
Report of the Royal Cornwall Polytechnic Society, 1834.
CHAP. III.]
TRANSFER OF POWER BY HYDRAULICS.
635
absorbs considerable power, unless the rods are well and truly supported,
and great attention paid to the proper
lubrication of the bearings.
It was proposed to supersede these
several appliances by the apparatus
shown, Figs. 173 and 174, which will be
rendered clear by the following brief
description. One arrangement may be
said to be a modification of the other,
since in each piece of apparatus ad-
vantage is taken of the incompres-
sibility of water, which is so confined
as to constitute, as it were, an hy-
draulic bar, acted upon by means of
plungers or pistons.
Diagonal Shaft Rods (Fig. 173).—
These are counterbalanced by means
of two plungers, one of which is pro-
vided with a weight-box.
(a) Plunger attached to main-rod.
(6) Pipe connecting the ram-case d.
(e) Plunger with weight-box.
(g) Guides for weight-box.
BET
SHAFT ROD
Fig. 173.
བ་
(h) Pipe communicating with cistern for supplying such water as may be
necessary to make up leakage.
(i) Small supply plunger which may be
attached to the apparatus when the pipe h can-
not be advantageously introduced.
The communication between the faces of the
two plungers is entirely free, and hence, if the
acting ram a be raised, the balance-plunger e
will fall and counterbalance the rods to the
extent of its weight less the trifling amount of
friction incident to the movement.
Fig. 174 shows the arrangement for a ver-
tical shaft, the power being taken from the
pumping-rod at one of the underground levels.
(a) Main-rod.
(6) Supply-pipe.
(c) Water-main.
(d) Pumping-ram fitted with side rods.
Vertical Shaft Rods (Fig. 174).
The
counterpoise arrangement is shown, in which the
parts are similar to the apparatus illustrated
above.
(a) Motive-ram fixed in vertical shaft.
SHAFT ROD
(b) Pipe connecting vertical with inclined plunger-case.
(c) Plunger, carrying weight-box. (See Fig. 173.)
h
Fig. 174.
636
[BOOK III.
PRACTICAL MINING.
(g) Guides for weight-box. (See Fig. 173.)
(h) Water supply pipe.
Transfer of Power.-The apparatus for this purpose may be single or
double acting. If single, an acting and pumping ram, coupled by a main
of pipes, will suffice. When double, the acting cylinder must be furnished
with a piston, forcing to a pumping-ram in one direction and lifting a
pumping-ram set elsewhere.
In the apparatus described it is evident that the reciprocatory move-
ments are unaffected by the position of the cylinders, and that these may be
placed either vertically or at any angle best suited to the special exigencies
of the situation. Neither is the motion affected by the distance between
the cylinders, nor by any abrupt windings or angular directions which the
passage between the cylinders may present. In counterbalancing pump-
rods, the apparatus requires but little room, whilst the movement of the
weight-box bears directly upon the line of pumping motion without
occasioning side or vibratory strain.
As a substitute for angle bobs, the hydraulic arrangement presents some
special advantages, inasmuch as it will sometimes be found to obviate the
necessity of employing a balance-beam; and as the pumping-rod is not
subjected to any cross strain, it follows that it may be permanently and
properly guided, and "rubbing" pieces are rendered unnecessary.
The transfer of power to any reasonable distance, whether at surface
or underground, may also be effected at a loss in friction much less than
would arise from the usual mode of transmission, whilst the pipes for the
retention of the water may be buried, carried down the corner of a shaft
through levels, and into the remotest heading, without causing the least
inconvenience.
At the Wildberg mines, Prussia, where hydraulic principles were early
applied, an engine with a ram 3 inches in diameter was placed 50 fathoms
below the surface, and 2,400 feet from an accumulator, weighted to 800
pounds to the square inch. The engine drew plungers and buckets 5 inches
in diameter, and enabled a piece of ground to be developed which other-
wise could not have been attacked for an indefinite period. A rotatory
pressure-engine at the same mines was constructed with two cylinders
each 2 inches diameter, and having a stroke of 9 inches. By adjusting the
stop-valve the speed could be made to vary from 2 to 20 revolutions per
minute. Overwinding was prevented by a contrivance placed between the
skip and stop-valve, which closed the latter at the required time. These
rotating engines are applicable to driving capstans, stamping, and crushing
mills. In mines where no surface water is available for effecting the
concentration of the ores, and where an engine has to circulate water for
this purpose, passing it, as is sometimes done, over water-wheels, one
pressure-engine, having two cylinders each 3 inches diameter, may be made
to take the place of a water-wheel 30 feet in diameter.
The hydraulic bar and accumulator system have various forms of
adaptation; for transferring power by single or double acting apparatus, for
counterbalancing shaft-rods, counterpoising flat rods, or changing vertical
into oblique motion. The transferring apparatus, which may be applied to
CHAP. III.]
DARLINGTON'S HYDRAULIC ENGINES.
637
inclined shafts, or for lifting water from the deep to the rise in colliery
operations, was introduced at the Phoenix mines, near Liskeard, where the
power was transferred 900 feet below the surface and at a distance of 700 feet
from the shaft.
The largest and most powerful hydraulic machinery erected in this
country for mining purposes was devised by the late Mr. John Darlington, of
Minera, Wrexham. About the year 1838 certain people, mostly residing
at Bakewell, decided to extend the operations at the Alport, Magpie,
Hubberdale, and Longstone Edge mines in Derbyshire, and to that end
it was necessary to drive adit levels and to erect pumping appliances.
Early in the year 1841 they availed themselves of the technical ability and
mining experience of the late Mr. Darlington. At Magpie and Hubberdale
he erected powerful steam-engines of the Cornish type for the purpose of
draining the mines. At Longstone Edge the ground was unwatered by
means of an adit level; while at the Alport mines he augmented the drainage
power by means of three hydraulic engines, two of which were placed in
Guy's shaft, and the third in a shaft on the Stanton side of the property.
The water for these engines was obtained from the Lathkill and Youlgreave
streams, which came together at the village of Alport. After a portion of the
water had done its work in the engines it was discharged with the water
from the pump-head into the Hill Carr Sough, an adit level about three
miles in length, extending from the mines to the river Wye in Darley Dale.
The engines in each case consisted of a direct single-acting pumping
cylinder fixed directly over the pump. To the larger engine was attached a
plunger-pole 42 inches diameter and 13 feet stroke, and to the smaller one a
bucket 36 inches diameter and 10 feet stroke. In wet weather these engines
made about 5 strokes and lifted 6,000 gallons of water per minute. The
large engine was fitted with two cylindrical valves, a cylinder with balanced
pistons for lessening the flow of water at the terminal portion of the stroke,
and with a relief-valve for mitigating the force of any shock which might
be consequent on bringing the column of water to a state of rest too
quickly. In the small engine the water was admitted to, and emitted from,
the pumping cylinder through a nozzle cylinder fitted with differential
pistons, which pistons received their movement through a tumbling ball
shifting a pair of small balanced pistons. The valves used in connection
with the pumping plunger were, in the first instance, formed with two beats,
contrived by Messrs. Harvey and West, of Cornwall; but subsequently they
were replaced by single-beat cylindrical valves arranged by Mr. Darlington.
Both bucket and clack in connection with the small engine had leather
valves, six in number, beating upon seatings inclined upwards towards
the centre. These, with the third engine referred to, worked continuously
for a period of about ten years, when the Alport mines were abandoned.
Other engines of a similar character were, however, erected by Mr.
Darlington at the Lisburne, Cwm-ystwyth, Tarlagoch, and Minera mines in
Wales.
In addition to these hydraulic engines, Mr. John Darlington designed,
about the year 1837, for use at the Haarlem Lake, in Holland, a compound
Cornish steam-engine, the high-pressure being placed within the low-
638
[BOOK III.
PRACTICAL MINING.
pressure cylinder, while for very heavy mine pump work he advocated the
employment of two direct-acting steam cylinders coupled together and set
over the shaft so as to allow of the passage of the capstan rope direct,
between the two cylinders, to any part of the pitwork.
At the Minera mines he introduced an apparatus system for bringing
up and letting down the miners, and for hauling the ore and vein stuff
to surface. As a "man machine" for use in metalliferous mines, it is not
likely to be surpassed either for its cheapness or simplicity of parts. For a
period of twenty years, during which the apparatus has been in constant
operation at the mines referred to, it has proved to be thoroughly efficient,
safe, and satisfactory.
In 1848 Mr. John Darlington undertook the management of the Minera
mines, and with an expended capital, and workings but half drained, he
projected certain exploratory works, which led to the immediate discovery of
large and remunerative quantities of lead ore, while he established and
maintained the success of the undertaking until his death, which occurred on
the 27th of April, 1877.
From the notices which have been given of the progress made in the
improvements of the Cornish pumping-engines, a general idea of the principle
and power of this application of steam may be arrived at. One or two
additional advantageous improvements were made. In the first instance, we
must mention Sims's engine. In 1815 Trevithick applied his patent plunger
at the Herland mines in Gwinnear. This engine did not answer, and Mr.
Sims entered into an arrangement for the use of Trevithick's invention. By
combining Trevithick's pole with a Boulton and Watt's engine, Mr. Sims
realised a duty, at Wheal Chance, in 1817, of 49,900,000. Several similar
machines were erected. In 1825 Captain Grose erected a 60-inch cylinder at
Wheal Hope, and was the first to introduce a system of clothing to prevent
radiation of heat. By this he raised the duty to 62,000,000, which he further
augmented in an 80-inch cylinder engine which he erected at Wheal Towan
in 1828 to 87,000,000. The following table was compiled by the late John S.
Enys, of Enys, a gentleman to whom Cornish mining is under large obliga-
tions for the painstaking inquiries which he carried out, especially in relation
to the duties of engines:-
Engines.
Largest cylinder in inches
Load in pounds per square inch
Newcomen's.
Watt's Low Pressure. Watt's High Pressure.
Often Expansive.
Expansive.
77
6 to 7/1/0
Period of use
•
Highest duty in million pounds.
Average duty in million pounds
1720 to 1778
3 to 7
63 (double)
6 to 9
1778 to 1812
90 single
12 to 9
191 in 1793
3 to 18
1812 to 1828
20 to 93
about 50
Depth of mines in fathoms
17 in 1779
90
200
290
The modus operandi of the Cornish engine is as follows: A cataract, or
mechanical appliance, is connected with the valve gearing, and so set as to
control the speed of the engine. In single-acting engines steam from the
boiler acts only on one side of the piston, while the other is open to the con-
CHAP. III.]
THE CORNISH PUMPING-ENGINE.
639
denser. With the admission of steam the motion of the piston commences,
which at the same time lifts a considerable counterpoise depending from the
opposite end of the main beam, known as the pump-rods. After the steam
has been admitted through the requisite space, the admission or steam valve
is shut, and the movement of the piston is continued to the termination of the
stroke by the impetus communicated to it at the commencement of its course
and by the expansion of the steam. Consequently, from the period of cutting
it off, the velocity of the piston decreases to the end of its course, whilst the
resistance remains the same.
At the end of the stroke the outlet or eduction valve closes, and the
equilibrium, or valve between the upper and lower portions of the cylinder,
opens, allowing thereby the steam above the piston to expand on its under
side, thus establishing an equilibrium between the two faces of the piston.
At this moment the pump-rod or counterpoise begins to descend, and brings
the piston to the top of the cylinder: When the piston has nearly obtained
this position the equilibrium valve shuts, and the steam intercepted at the
top of the piston is gradually compressed until the engine is brought to a
state of rest. The steam and outlet valves are again opened by the action of
the cataract, and the motion is thus continued.
The cylinder in the Cornish engine is fixed in such a position that the
condensed steam in the jacket can return to the boiler. A temperature in
the latter of 84° was only lowered 7° in the jacket, so well was it protected by
clothing. Little waste of steam is caused by the intermediate space between
the valves and piston, since the former are fixed as close to the cylinder as is
possible. The whole amount of friction, including imperfect vacuum, is found
not to exceed 3 lbs. per square inch. In many machines the steam is
wire-drawn on its entrance into the cylinder, it being urged that if it were
admitted on the piston, beyond a certain pressure the impact would be
liable to injure the working parts. There is, however, no valid justification
for the employment of this system, since we have only to increase the size
of the pipes and valves to obtain an equal effect with steam of less pressure
in the boiler.
The term "Duty," as previously explained, is the nett effect produced from
the consumption of a given quantity of coal. In Cornwall the diameter of the
cylinder of a steam-engine is employed to convey an idea of its power; but
its economic performance is invariably determined in relation to the quantity
of coal consumed to produce a given effect. This expression may therefore
be formulated as the amount of force and weight of water lifted, multiplied by
the space through which it acts, divided by the weight of coal consumed
(fx.s).
Messrs. Boulton and Watt appealed to this test of the efficiency of
their engines when engaged in ascertaining the saving of coal due to their
invention, and referred to it in all disputes respecting their legal rights.
Watt also invented a counter to record the number of strokes made by an
engine, which counter was usually attached to the main beam. This instru-
ment has been subject to several modifications. Mr. Newton, the philo-
sophical instrument maker of Camborne, has constructed a counter of great
delicacy, possessing many advantages.
C
640
[BOOK III.
PRACTICAL MINING.
It will be interesting in this place to give some examples of the large
improvement which has been made in some recently-constructed pumping-
engines, which are applicable to pumping from deep mines. From the
official statement of the trial made in February, 1883, the following particulars
are obtained. The engines under trial were two independent compound
rotative beam-engines, constructed by Simpson and Company, London,
for the West Middlesex Water Works, Hammersmith.
These were compound Woolf beam-engines, the high and low pressure
cylinders being on the same side of the beam and opposite to the crank.
The pump, which is double-acting, with four valves, is placed at the end of
the beam opposite to the cylinders.
The cylinders are completely steam-jacketed with boiler steam; the low-
pressure cylinders have separate steam and exhaust valves.
The coal used was Nixon's Navigation Welsh, obtained from Messrs.
William Cory and Sons, and was of very good quality.
Three boilers were used on the trial, each 6 feet diameter by 28 feet long,
the flues being 3 feet 6 inches diameter, and each fitted with six Galloway
tubes. The feed water was taken from the hot well and pumped direct into
the boilers.
The leading dimensions were-
Diameter of Small Piston
Stroke of Small Piston.
Diameter of Large Piston
Stroke of Large Piston
Diameter of Main Pump
Stroke of Main Pump
•
•
•
•
Ft. ins.
2 5
•
5 5
3 11/
I 518
8 0
The engines were each to pump 3,456,000 gallons in 24 hours, and the
duty to be done, under the contract, was not to be less than 96.4 million foot
lbs. per 112 lbs. of coal, after 5 per cent. had been deducted from the pump
displacement.
OBSERVATIONS TAKEN.
Date of Trial.
Duration
of Trial.
No. of
Engines.
Revo-
lutions
from
Counters.
Average
Lift of
Water.
Boiler Baro-
Pressure. Imeter.
Vacuum.
Temperature of
Air Pump
Coal
used.
Injection. Discharge
1883.
February 7th
9th
·
Hours.
24
Feet.
Lbs.
Inches. Inches. Degrees. Degrees. Tons.
70
24
738
25,920
187.7
50
30
28.5
46
26,325 187.2
50
29.6
28.1
46
72 3.377
77 3.425
RESULTS.
No. of
Engine.
Actual
Horse-power
in Water
lifted.
Coal consumed
per actual
Horse-power
per hour.
Duty per 112
lbs. Coal in
Million foot
lbs.
£18
Average
indicated
Horse-power.
Coal consumed Gallons pumped
per indicated
Horse- power
per Hour.
in 24 Hours
after deducting
5 per cent.
Lbs.
164.35
166.46
1.91
I'92
116 1
115.5
206'47
206'02
1.53
1.55
4,160,913
4,225,926
The following extracts from the engineer's report place the trials in a
satisfactory light :-
“The first trial with No. 7 engine took place on the 7th inst., commencing
CHAP. III.] THE IMPROVEMENT IN PUMPING-ENGINES.
I
I I
641
at 11 o'clock A.M., and continued for 24 hours, ending at 11 o'clock A.M. on
the 8th inst. The engine made 25,920 strokes, or an average of 18 strokes
per minute, and pumped 4,160,913 gallons of water, an average of 1877 feet
high, and consumed 3 tons 7 cwts. 2 qrs. 4 lbs. of coal, which gives a result of
1'91 lb. of coal consumed per pump, or usefully exerted horse-power, per
hour, being 17 per cent. less than the guaranteed quantity. This result is
equivalent to a duty performed of 116,100,000 lbs. of water lifted 1 foot high
with 1 cwt. of coal; the pump horse-power was 164'35, and the indicated
horse-power 206:47.
"The next trial, with No. 8 engine, took place on the 9th inst., commencing
at 12 o'clock noon, and continued for 24 hours, ending at 12 o'clock noon on
the 10th inst. The engine made 26,325 strokes, or an average of 18.28
strokes per minute, and pumped 4,225,926 gallons of water, an average of
187′2 feet high, and consumed 3 tons 8 cwts. 2 qrs. of coal, which gives a
result of 1.92 lb. of coal consumed per pump horse-power, being 163 per
cent. less than the guaranteed quantity. This result is equivalent to a duty
performed of 115,500,000 lbs. of water lifted 1 foot high with 1 cwt. of coal;
the pump horse-power was 166.46, and the indicated horse-power 206.2.”
The contract for these engines was very stringent, for not only had the
pump piston and valves to be proved quite tight to the engineer's satis-
faction before the trials, but 5 per cent. was to be deducted from the pump
displacement. As this is not usually done, we have given in the following
table the results without deducting the 5 per cent., in order that a com-
parison may be made between the trials of these and other engines. The
pump pistons and valves were tested, and found quite tight under the full
head before the trials, and there can be no doubt but that the pumps
delivered a quantity of water equal to their displacement.
No. of
Engine.
Actual
Horse-power
in Water
lifted.
Coal'consumed
per actual
Horse-power
per Hour.
Duty per 112
lbs. of Coal.
Gallons of
Feed Water
per indicated
Water pumped Horse-power
in 24
Hours.
per Hour.
Feed Water evaporated
from Temperature of Hot
Well per lb. of Coal ex-
cluding Jackets which
circulated back to Boilers.
1138
173.00
175 19
Lbs.
1.821
1.825
Foot lbs.
I21,779,242
Lbs.
121,512,329
4,379,903
4,448,343
14.56
14.78
Lbs.
9'54
9.53
It may be remarked that no increase has been effected in the economical
performance of the Cornish pumping-engine in Cornwall for many years,
and it is thought that this cannot be expected until steam of a higher pressure
and expanded to a corresponding degree be employed. The idea is gaining
ground among Cornish engineers that advantage will be gained by doing
away with the parallel motion by running the piston-rod in guides. It is
also proposed to fix the steam valve on the cylinder cover, and the equi-
librium in the piston, as well as to work the steam expansively on both sides.
of the piston instead of one side only.*
* This question is more fully discussed in the "Records of Mining and Metallurgy," by Phillips and
Darlington; and those who are interested in the important problem of the best mechanical appliances in
use for drainage of mines, should consult also Mr. Stephen Michell's work on "Mine Drainage, being a
Complete and Practical Treatise on Direct Acting Underground Steam Pumping Machinery."
642
[BOOK III.
PRACTICAL MINING.
In Cornwall slow combustion is usually considered desirable, and boilers
are usually made of large dimensions. At East Wheal Rose, Michell's 85-
inch cylinder, 10 feet stroke, was furnished with four boilers of the following
dimensions: two 36 feet by 6 feet, one 38 feet by 64 feet, and one 34 feet by
6 feet, weighing together 45 tons. The steam is raised to a maximum
pressure of 30 lbs. per square inch, and the consumption of coal, when
making 4 strokes per minute, was 3.6 lbs. per horse-power per hour.
Mr. Wickstead,* who made many experiments on Cornish cylindrical
boilers, writes: "My experiments upon four Cornish boilers show that, when
the consumption of coal per square foot of grate per hour was only 2·475 lbs.
and the water evaporated per hour equal to 23.5 cubic feet, 8.258 lbs. of water
were evaporated from 80° by 1 lb. of coal, and when the coals per square foot
of fire-grate were equal to 5,013 lbs., or rather more than double, 8.605 lbs.
of water were evaporated from 80° by 1 lb. of coal, showing an advantage of
4 per cent. in favour of the more rapid combustion and evaporation.
"The following table shows the mean results of all my trials upon four
cylindrical boilers, lasting 504 hours for quick combustion and 514½ hours for
slow combustion :
Combustion.
Lbs. of Coal per
Hour.
Cubic Feet of Water
per Hour.
Lbs. of Coal per
Square Foot of
Grate per
Hour.
Quick
342
46.9
4.682
Slow
188
25.4
2.596
Lbs. of Water evapo-
rated per lb. of Coal
from 80 Degrees.
8.524
8.421
Ratio.
100.
98.8
"We some years since experimented on two tubular boilers applied to
an 80-inch cylinder pumping-engine, at Par Consols mine, in the county of
Cornwall, in order to ascertain their evaporative powers. These boilers
were each 32 feet in length, 6 feet 3 inches in diameter externally, and 3 feet
10 inches internally. The fire-grate was inclined towards the bridge, having
a length of 6 feet with a breadth of 3 feet 10 inches. They were also pro-
vided with an arrangement by which the feed-water was heated to near the
boiling-point before entering the boilers. . The water was heated to
about 212° by means of the heat absorbed from the gases passing through
the flues, and of which the temperature was reduced to about 300° before
being discharged through the stack. The heating surface of both boilers
was 1,900 square feet, and the warming apparatus 500 square feet, or
together 2,460 square feet.
Arrangements having been made for
measuring the water, the experiment was begun; and, at the expiration of
46 hours it was found that 95 cisterns of water had passed into the boiler,
and that 11,730 lbs. of coal had been consumed, in order to evaporate
119,700 lbs. of water from the temperature of 92° Fah., which gives
10,204 lbs. of water evaporated from that temperature for every pound of coal
consumed. If we take 212° as the standard temperature, we find that each
pound of coal had evaporated 11,428 lbs. of water from the boiling-point.
•
The author, when acting as Secretary to the Royal Cornwall Polytechnic
Society, was induced to make a series of experiments "on the quantity of
* "Wickstead on the Steam Engine."
CHAP. III.]
EXPERIMENTS ON CORNISH BOILERS.
643
air supplied to the fire-places of Cornish engines." The results of this
inquiry were as follows, which are reprinted from the Transactions of the
Society.
Although from its economy of fuel, combined with high mechanical
power, the Cornish pumping-engine has attracted considerable attention,
one point in connection with the subject has hitherto been but imperfectly
determined.
The heat developed from any fuel during its combustion is dependent
mainly upon the carbon that it contains. The conversion of the whole of
that carbon into carbonic acid is the result of perfect combustion, and this
requires that two equivalents of oxygen should be obtained from the air for
every equivalent of carbon in the fireplace. Each atom of carbon thus made
to combine represents a fixed mechanical value; consequently, a theo-
retically perfect arrangement would be one in which all the carbon could be
converted into carbonic acid, and in which the air supplied gives precisely
the required quantity of oxygen. The caloric due to the combustion of the
hydrogen is, in the case of coal, so small in relation to its other constituents
as to be of comparatively little moment in the calculation.
It becomes consequently an interesting problem to determine, with as
much accuracy as possible, the quantity of air supplied to the fireplaces of
Cornish boilers. It may appear easy to ascertain with tolerable correctness
the quantity of air passing through fireplaces constructed as those of the
boilers of the Cornish steam-engines are.
If the temperature of the air had been uniform throughout the whole
length of the flues, i.e. from its first entrance into the fireplace, to its exit
from the top of the chimney, its ascensional force might be calculated from
the difference between the weights of the heated column, and a column of
air of the same height at the observed temperature of the atmosphere; and
thus the quantity of air passing the fireplaces in a given time might be
readily ascertained. This uniformity of temperature does not, however, exist,
which is alone sufficient to render all calculations on the subject exceedingly
intricate.
The alterations in temperature in different parts of the flues, and in the
stacks of some Cornish engines, which were determined with much care,
together with the differences in the temperature of the external air, will at
once show how complicated this question is.
On the 29th June, at Tresavean mines, the thermometer stood at .
The coaling place of the large engine, 12 feet from the fire
At 2 feet from the fire
•
One foot from the ash-pit
In the flue, 30 feet from the fire
At the end of the flues, 101 feet from the fire
•
On the 13th September, at North Roskear mine, the temperature of the
air in the flue nearest the fireplace was
At the bottom of the stack, 122 feet from the fireplace.
Fab.
72°
87°
90°
110°
330°
190°
340°
234°
These results show that a large amount of calorific absorption is going
on during the passage of the gaseous current through the flues and
chimney.
Proceeding with this inquiry, it was resolved, in the first place, to deter-
TT
644
[BOOK III.
PRACTICAL MINING.
mine, with precision, the distance through which the air had to travel from its
leaving the fireplace to its quitting the stack.
The following are the measurements obtained at three of the most
important engines in Cornwall :—
THE NEW ENGINE AT TRESAVEAN.
From the fire-door to the end of the flues
Length of stack flue
Height of stack
•
TAYLOR'S ENGINE, UNITED MINES.
From the fire-door to the end of flues
Height of stack
•
WEST'S ENGINE, NORTH ROSKEAR.
IOI feet.
40
60 ""
201
""
107 feet.
80
187
""
Tube of boiler
Flues
•
Between ends of boilers and stack
Stack
37 feet.
72
12
""
""
90
2II
The author was enabled to determine with precision the volume of air in
the flues, and the chimney, at North Roskear mine, and from similar data
the capacity in each case was deduced.
Flues through tube, allowing for fire-bridge=432 feet; for
three boilers, say
Flue over one boiler 199 feet, three of them, say
=
Flue under one boiler=567 feet, three of them, say
1,296 cubic feet.
Between boiler and stack.
Ditto to damper
Stack
•
597
1,701
3,594
.45
""
""
45
607
""
4,291
Hence we approximate very nearly to the truth, when we consider the
space occupied by the air, as being 4,291 cubic feet; which at 60° Fah. and
the barometer at 30 inches, would be equal to say 328 lbs. avoirdupois.
This requires correction for the expansion due to the elevated temperature
of the flues. Without going into the details of this correction, it may be
sufficient to state that it was determined that 238 lbs. of air were contained
in the flues and chimneys at North Roskear mine.
It must not be forgotten that the gases and vapours from the coal which
pass off unconsumed, form a portion of this amount. Somewhat more than
800 lbs. of coal are burnt in each boiler in 24 hours, by the combustion
of which carbonic acid and water are formed; hence the flues and chimney
contained nitrogen, carbonic acid, and watery vapour, together with uncom-
bined oxygen.
The rate at which the air traverses the flues was determined by placing,
immediately in front of the fire, some tow saturated with oil of turpentine,
and closing the fire-door rapidly after it was thrown in. The dense black
smoke generated in this way being seen at the top of the stack, gave, after
numerous experiments, the following mean results :-
CHAP. III.]
THE CORNISH SYSTEM OF STOKING.
645
Tresavean.
North Roskear.
United Mines.
24
M.
I
I
2
2 H
I
52
3381
S.
M.
S.
M.
S.
50
55
2 2 2 2
00
нннN
I
40
I
55
I
52
2
00
ΙΟ
2 3
The gaseous products formed by the combustion of the coals may be
estimated at 15 cubic feet per minute; this must be deducted from the
contents, together with some other allowances arising from various interrup-
tions to the currents, &c. This will reduce the quantity of air to about
3,000 feet.
At the mean pressure and temperature, this will be equal to
about 110 lbs. of air passing through the flues per minute. This air, having
passed the fire, should have been deprived of its oxygen. Analyses were
therefore necessary to determine this point. The air was collected in a
receiver from the stack by a hole made in the brickwork, and subsequently
removed in stopper bottles, and analysed with as little delay as possible.
The eudiometric process was employed. In all cases the carbonic acid was
first absorbed by caustic potash, and averaged one-ninth the total volume
operated upon.
Thirty cubic inches of air from the nearest flue of the engine, Tresavean,
gave
Ditto from flue nearest stack, ditto
Ditto (a second experiment) from nearest flue, ditto
Ditto from nearest flue, North Roskear, ditto
Ditto
ditto
ditto
Ditto from end flue, Taylor's United mines, ditto
C 02
3ΟΙ
3:00
2.98
3.20
3'07
2.75
The proportion of oxygen to nitrogen in the atmosphere is about one-
fifth, thus we learn the quantity which has entered into combination with
carbon and hydrogen to form carbonic acid and watery vapour, to develop
available heat.
A few experiments with charcoal will show that, after its combustion in a
close vessel, the air still contains sufficient oxygen to support the combustion
of sulphur, and consequently that it is not possible to deprive atmospheric
air of all its oxygen, by ignited coal alone. This accounts for the oxygen
found in the flues. The results obtained appear to indicate that the admis-
sion of atmospheric air has in these cases been so regulated as to produce
the best practical effects. If a less quantity had been admitted the fires would
not have burned freely; and if, on the contrary, a larger amount had entered,
it would have exerted a cooling influence and diminished the duty in propor-
tion to the coals consumed. Experience has shown Cornish engineers that
the best duty is obtained when all apertures through which strong currents
could find their way into the apparatus are closed, and just sufficient air
admitted to support a moderate but not rapid combustion.
The enginemen of Cornwall observe a fixed rule in the management of
their fires. When coal is first introduced they merely spread it over the sur-
face of the fire, and never stir or stoke it except at the time of cleaning. They
then shut down the damper to prevent the rush of cold air, which would have
the effect of lowering the temperature of the steam in the boiler. Subse-
quently they turn the unconsumed fuel on one side, and after raking off the
TT 2
646
[BOOK III,
PRACTICAL MINING.
clinkers turn the fuel back on the clean bars, in order to repeat the operation
on the other side. The fire before cleaning is about 6 inches deep, and after
cleaning about 3 inches.
It is important to have some useful rule for determining the strength of
boilers. It is generally considered that the strength is in direct proportion
to the thickness of the plates, and inversely as their diameters. Practice
appears to have settled that the iron plates cannot be less than a quarter of
an inch nor more than half an inch in thickness. The tensile strain of good
malleable iron is estimated at 56,000 lbs. One-third of this is regarded as the
extreme force which it should bear, or 18,000 lbs. Mr. John Darlington says:
'From this sum it is necessary to make liberal deductions for difference in
the quality of iron, and also for bringing the pressure within the limit of
safety." The following numbers represent the strain per square inch of
section reduced to meet the above condition:
Common Yorkshire iron plates
Best
2,500 lbs. per square inch.
Common Staffordshire
Best
""
4,000 "
""
3,000 ""
5,000 ""
""
There are several questions which bear directly on the improvement
of the steam-engine which may be mentioned, though they would occupy too
much space to receive full consideration in this volume. These are super-
heated steam and the expansion of steam in superheating, the evapora-
tion of vesicular water, the spheroidal state as described by Boutigny, and its
influence in producing boiler explosions. For a full description of the
present state of our knowledge of these conditions, the reader is referred to the
treatises which have been published in connection with this important
question.
In mine pumping-engines the most serious accidents often arise from
the breaking of main rods, which naturally takes place during the time
that the cylinder is taking steam. The piston being suddenly relieved
of its load, considerable damage is the result; a sudden decrease of
load on the engine from any cause whatever endangers its safety, and the
spring beams must suffer if the engineman is not at his post. What the
engineer would do to prevent such a result would be to throw up the equili-
brium catch immediately the engine evinces a tendency to what is technically
called "coming indoors" too fast; but the engineer cannot always be pre-
pared for such emergencies, nor could he, if stationed at the handles, throw
up the catch in time. Husband's safety governor is therefore designed to
act simultaneously with the engine, and is thus described in reference to
Fig. 175.
The plunger z makes its up-stroke with the up-stroke of the engine, and
draws its water through the valve R, forming part of the ordinary cataract
cistern. The water so pumped is discharged into the same cistern through
the regulating cock, D, which is adjusted by means of a rod (M) from the
engine floor. If the engine increases its speed above the normal rate of
working, from any cause whatever, the water is throttled in its discharge
through the cock D, and a pressure is thus imposed upon the piston E, tend-
ing to raise it; as the piston E rises, the lever S comes in contact with the

CHAP. III.]
HUSBAND'S SAFETY GOVERNORS.
647
catch Q, and thereby lifts the equilibrium catch B; to increase the effective-
ness, an additional cock (N) is provided, which closes as the piston E rises,
thus increasing the force imposed on the said piston.
The importance of this arrangement will be obvious to any one acquainted
with the steam-engine, and
its value in meeting the
necessities of the case is
its strong recommendation.
Before closing this brief de-
scription of the steam ma-
chines used in the drainage
of mines, some notice must
be given of their use for
other mining purposes, and
especially for the winding-
engine and for the "Man-
Engine" employed for rais-
ing and lowering the
miners.
the
By the substitution of
steam winding-engine
for the horse-whim, a con-
siderable economy has been
effected. The machinery of
a winding-engine in Corn-
wall is generally more
costly than that which is
used in the colliery dis-
tricts, but they wind more
slowly, and the weight lifted
is generally considerably
less. The difference in
expense between steam and
B
A
M
Fig. 175.
horse whims has been estimated, by Mr. Joseph Carne, to exceed 50
per cent. in favour of the former. Most of the engines used for winding
in Cornwall have been designed with a view of economising fuel, but it
is questionable, when this result is obtained, whether the final result is so
satisfactory.
A machine of this kind should not only be cheap in construction, but it
should be simple in its action, have every facility for the regulation of speed,
and possess the high merit of durability. Horizontal cages are frequently
preferred to vertical ones, and in the colliery districts they adopt winding
directly from the fly-wheel shaft, rather than placing the rope on a drum set
in motion by toothed gearing. When the former method is used, a steam
drag is connected with the fly-wheel, which the engine-driver brings into
operation as may be required.
The following particulars show the prevailing conditions of the winding-
engines of Cornwall and of North Wales :-
648
[BOOK III.
PRACTICAL MINING.
Average of Mines
in Cornwall.
Minera Lead Mine, North Wales.
Character of Engine.
Diameter of cylinder
Length of stroke
•
Number of revolutions per minute
Speed of piston in feet per minute
Pressure of steam on piston per square
inch
•
Mean diameter of drums
Speed of rope in shaft per minute
Weight of load drawn
Tons drawn per day of 8 hours
Depth of shaft
Diameter of drawing pulley
•
No. I.
No. 2.
Vertical Condensing. Horizontal Spur Gear. Horizontal Spur Gear.
22 inches
14 inches
5 feet
15 to 20
150 to 200 feet
3 feet
50
14 inches
300 feet
3 feet
50
300 feet
12 lbs.
4
150 feet
IO Cwt.
14 lbs.
5
250 feet
26 cwt.
15 lbs.
4
250 feet
25 cwt.
100
variable
5
100
120
150
170
7
100
4
REMARKS:-No. 1, winding from one shaft; No. 2, 2'00 tons, if from two shafts.
TABLE SHOWING THE DUTY PERFORMED BY SOME OF THE BEST CORNISH WINDING ENGINES,
FROM THE YEARS 1848 TO 1858.
(From "Brown's Cornish Engine Monthly Reporter.")
Year.
Mines.
Engines and their Power.
3
No. of Kibbles drawn.
Average Depth.
Average Weight of a
Kibble of Stuff
Average Number of
Kibbles drawn by
consuming I cwt.
of Coal.
Pounds raised 1 Foot
high by consuming
I cwt. of Coal.
1848 | Fowey Consols
Par Consols
Callington Mines
Great Polgooth
1850 Fowey Consols
Great Polgooth
Trelawny
Callington
•
1852 Fowey Consols
Great Polgooth
Par Consols
Devon Great Consols
1854 Fowey Consols
Fowey Consols
Great Polgooth
Par Consols
1856 Fowey Consols
Par Consols
Great Polgooth
South Caradon
1858 Fowey Consols
Par Consols
Fowey Consols
South Caradon
H.P.
Fms.
Lbs.
Millns.
22-in. double
•
29 5,300 246.8 1,000
19.8
29.3
24-in. and 13-in. combined 17 5,387 1014 1,008
37.7
23.1
22-in. double
29 5,203 111.5 | 1,008
26.0
17.5
22-in. double
•
•
22-in. double
•
·
22-in. double
•
29 5,198 130.5 700
29 5,798 255.1 | 1,000
29 4,919 110.5 1,500
15.0
II'O
18.3
28.0
18.1
22.0
24-in. and 14-in. combined 34 5,321 83.2 900
21.5
17.6
18-in. double
•
22-in. double
22-in. double
24-in. single
19 3,472 113.5 1,008
16.2
II'I
•
29 5,775 257.0 | 1,000
19.4
29.9
29
3,291
120.9 1,008
10.1
20'4
27
7,729
89.5 1,008
40'5 23.7
30-in. and 16-in. combined 52 5,231
96.5 1,456
19.1 18.7
22-in. double
•
•
29 4,133 255.6 | 1,000
19.4
29.8
18-in. double
•
•
19 2,979 175.6
850
21.6
19.3
22-in. double
•
29 3,043 162.7 1,008
ΙΟΙ 18.0
24-in. single
22-in. double
•
27 5,556 97.4 1,008
294,513 236.7 | 1,000
30.4
19.8
20.3
28.8
24-in. and 13-in. combined 33 2,785 117.9 1,008
33°2
23.7
22-in. double
•
29 3,838 147·9 | 1,008
30-in. and 16-in. combined 52 2,012
10.7
16.3
89.8 1,203
15.6
13.5
22-in. double
•
•
29 5,887 233.1 1,000
17.5
24.5
24-in. single
•
18-in. double
•
27 5,530 1140 1,008
19 2,632 143.8
34°3 25·8
850
18.3
13'4
•
30-in. and 16-in. combined 52 2,367 88.4 1,203
11.9 II.2
Another application of steam power has been made in the “Man-Engine,"
which has been employed in some of the mines to raise and lower the miners.
A brief description of this labour-saving machine must be given. Mr.
M. Loam, at a meeting of the Devon and Cornwall Miners' Association,
CHAP. II.]
LOAM'S MAN-ENGINE.
649.
read a paper on its history, which supplies the information required.
After referring to what had been done in the way of advancing steam-
engines after Watt, until the duty of the Cornish engine was raised to
a maximum of 80 millions, and reduced the cost of drainage two-thirds
which led to a rapid and successful development of our mines, this rapid
development involving great and increased physical strain through climb-
ing upon the miners, which was felt to be a serious and increasing evil, he
stated that so great was the exhaustion in the Consolidated mines, then one of
the most important and deepest, that the older and experienced miners were
unable to work in the deeper levels from sheer inability to climb from such
depths, and young and inexperienced miners had to be employed in them.
The Royal Cornwall Polytechnic Society took the matter up seriously, and
pointed out the pernicious consequences of this climbing of the miners,
besides exhausting, as it did in the Consolidated mines, one-third of the
whole physical strength and work. The Society, through the liberality of
Mr. Charles Fox, offered a premium in 1833 "for the best improvement on
the present method of ascending and descending mines." It was under the
medical, and not the physical aspects, that this subject was first brought
under the late Mr. Loam's notice in 1827. The late Mr. J. Paul, then the
leading surgeon in Gwennap, and one long esteemed in his profession,
had watched the increase of pulmonary complaints among miners through
climbing, and at one of the Consolidated mine meetings he called attention
to it, said it was getting worse as the mines deepened, and suggested that
their engineer should devise some means to supersede the ladders. Mr.
Loam's first thought and suggestion was the obvious method of the collieries
to raise the men with ropes, but the miners would not listen to being brought
up like coal and rubbish; besides, the ropes might break and the men be
killed, so that a better plan must be devised. It was this emphatic con-
demnation of the ropes that led Mr. Loam to discard them, and induced him
subsequently to adopt the rod. In adopting the rod and fixed platforms in-
stead of rope, it was found upon consideration that, apart from its assured
safety, it was capable of greater facility and rapidity of discharge. With a
rod 260 fathoms long, and conveying 130 men 2 fathoms apart, each travel-
ling 10 fathoms per minute, it would equal 1,300 per man per minute with a
single rod, and with two rods this rate would be doubled, and which no means
of transit by rope could equal. The rod also enabled each miner to step on
and off at any given point or level without stopping or interfering with the
transit of others to their various levels. Mr. M. Loam well remembered his
father's enthusiasm about this invention. It was the great topic of his
thought and conversation, and the date of the invention must have been
about the year 1829. It was hoped that the man-engine would have been
adopted at the Consolidated mines, as they were then very rich and deep,
but from some cause or other, the matter was deferred and ultimately
dropped. But the action of the Polytechnic Society revived hopes, and Mr.
Loam entered warmly into a contest for the premium offered, and was able
to bring out his scheme in all its details. Mr. Paul was greatly pleased.
at Mr. Loam's success, and especially as the Polytechnic Society had
approved of the model. But for some years after that there appeared no
650
[BOOK III.
PRACTICAL MINING.
D
ค
O
O
prospect of its adoption. Although the society had for years offered
premiums on its improvement, the mines failed to adopt it. At length
Mr. Charles Fox and others offered a premium of £500, through the Society,
to any Adventurers who would erect it. The late Rev. Canon Rogers also
offered a premium of £50 to the engineer who should be the first to introduce
an effective system for lowering and raising the miners.
The first public trial was successfully made on the 5th of
January, 1842, the man-engine, with two rods, as shown
on Fig. 176, having been fixed to the depth of 27 fathoms.
In the year 1841 negotiations were opened with one or
two mines, but unexpected delays interfered, and no pro-
gress was made until the 23rd of December, when pro-
posals came from Tresavean mine, engaging on their part
to erect suitable machinery to the depth of 200 fathoms, on
the condition of being paid £300 towards the first 100
fathoms, and £200 more on the completion of the second
100 fathoms. The society felt themselves justified in closing
with this offer, and after the engine had been erected in
1842, and its success was an accomplished fact (its results
were watched with keen interest by the society, and not
less by the miners themselves), the premium of £500 was
eventually paid to the Adventurers in Tresavean mine
(the first portion of £300 being paid by the society when
the first 100 fathoms was completed, and an additional
£200 when the second 100 fathoms should have been suc-
cessfully fixed), and also the premium of £50 to Mr. M.
Loam, by the author of this volume, who was then secre-
tary to the Royal Cornwall Polytechnic Society. Mr.
Loam subsequently took a first prize for an improvement
in the man-engine, and although others competed, their
plans were not considered of such merit as to deserve a prize.
It has been carefully calculated that the cost of working the engine is not
above one penny per man to the bottom of the mine. The miners at
Tresavean mine joined in expressing their approbation of, and their thank-
fulness to the society for, the engine in unqualified terms.
O
Fig. 176.
In 1845 a second Man-Engine was started at the United mines, the
same society paying £103 as a contribution towards the expense of erect-
ing it. In 1851 a third engine was erected in Fowey Consols mine, under
the direction of Mr. W. West, engineer, and Captain Puckey, agent. The
construction of this machine differed in several respects from those which
had been erected at Tresavean and the United mines. The plan had, however,
been submitted to the judges at the Exhibition of the Polytechnic Society,
and it was found to work extremely well.
Similar Man-Engines have been constructed at Dolcoath mine, and also
at the Devon Great Consols, near Tavistock.
It will be easily understood that the two rods, with the platforms, fixed
at regular distances, as shown in Fig. 176 above, moving alternately, will
admit of a miner ascending or descending if the rod moves with a 10-feet
CHAP. III.]
SINGLE-ROD MAN-ENGINE.
651
12000)
stroke-over 10 feet at each stroke of the engine. He steps, when the plat-
forms come together-which they do when the crank is passing over the
dead-point of its motion, and consequently when there is a
brief rest-from the platform on which he stands to the
other; the rod then begins to make its upward movement,
and he is carried up another 10 feet. Thus without any
fatigue he is lifted to the surface or carried to the bottom.
Single rods (Fig. 177) are more frequently used; then the
platforms are fixed to the side of the shaft. The miner is
represented as stepping from the fixed platform to that
which is about to ascend, and he is carried up 10 feet, when
he steps off on to the fixed rest, and remains on it until
the platform on the rod, 10 feet above that which he has
left, has come down, and rests opposite to the one on
which he stands, he then steps off, and is carried up another
10 feet. The rate of the machine with one rod is of course
slower than that of the machine with two rods.
We shall have occasion to notice on a future page the
influence on the health of the miners of climbing from
great depths. It has been shown that the disease known
as "miners' consumption" is largely due to this cause.
The Man-Engine, therefore, as a means for removing the
injurious influence, must be regarded as a great blessing,
and it is to be regretted that it is not more generally
applied. This is mainly due to the unfortunate system
under which the mines of Cornwall and Devon are worked
-a system which does not encourage the holder of shares
to take any special interest in the mines themselves, his
interest being confined to the market value of the shares.
which he holds.
Fig. 177.
MINING TOOLS.-In the chapters devoted to the boring of rock and to
the dressing of ores several of the tools employed have been already
described. There yet remain, however, tools which are important to the
practical miner, and which demand attention. It will be more consistent
with the purposes of this volume to deal with the principles involved in the
construction, than to enter into any directions as to the use of tools.*
*
Borers.-In writing of rock-boring by machinery, a short space has been
devoted to the consideration of tools or bits which have been employed, and
a woodcut (Fig. 115) is given of five descriptions of bits. At one time the
cutting ends of all borers were of hardened iron, but now they are always
made of steel. Shear steel is generally employed for the bit, and this or
blister steel is welded in a split weld to a bar of iron. Striking borers of the
above class have been since 1851 superseded by such as are made entirely of
cast steel, which has been drawn under the tilt-hammer into octagonal bars,
* Those readers who desire for practical purposes to make a selection of the tools required for
mining operations and for the dressing of ores, or who are anxious to know kinds of metal best suited
for special purposes, should consult the "Manual of Mining Tools, comprising Observations on the
Materials from and Processes by which they are manufactured, their special Uses, Applications, Qualities,
and Efficiency," by William Morgans, which is accompanied by an "Atlas of Mining Tools." Crosby
Lockwood and Co. 1871.
652
[BOOK III.
PRACTICAL MINING.
and is familiarly known in the market as "borer steel." Steel possessing
more tenacity than iron, admits of being made into borers which are lighter
than those made of iron. A bar of steel being stiffer than an iron one, it will
transmit with greater effectiveness a hammer blow than an iron bar will do.
When the blow of a hammer is delivered upon a bar of metal a certain
amount of inertia has to be overcome, that being determined by the quantity
of matter between the end receiving the blow and the end in the bore-hole
from which the effect is derived. The quantity of matter in a steel borer
being less than that contained in an iron one of the same length, it will
convey the force more effectively. On this principle a short borer is found
to exert more power than a long one.
The bit of a borer is formed by flattening the end of the bar until about a
quarter of an inch thick, and a little wider than the diameter of the hole which
is to be bored. When used in boring hard ground, the face is best formed
by tapping it with a light hammer, and then by carefully using a file. By
hammering in the corners of a bit, the splay should be preserved to the ex-
tremity. This is done by properly inclining the face of the hammer, which
can only be learnt by experience. The tempering of borers is important,
and demands considerable attention. The cutting end, about 4 inches,
previously sharpened, is heated to cherry redness in a clear fire; it is then
immersed in cold water, as free from saline matter in solution as it can be
obtained, to the depth of of an inch. The steel or iron of the bit is thus
thoroughly chilled or hardened. The whole of the hot portion of the bar
should then be plunged into the water for a short time and afterwards with-
drawn. The colour of the steel in the process of tempering varies from
straw-yellow to purple. Shades of brown produce a good temper and are
favourites with many smiths. Heating the steel to the exact temperature
should be carefully secured, and the knowledge of this is obtainable only
by carefully observing the results of continued practice.
1
4
+
The pulverised matter formed in boring has to be removed from the
hole, and for this purpose "scrapers" are used. They are usually made of
light iron rod of from inch to inch thick, sufficiently long to reach the
bottom of the hole, the scraping end flattened out to the diameter of the
hole with a ledge for receiving the "boring dust" or "meal" (or when
damped "sludge"). "Drags" and "spoons
Drags" and "spoons" are also used for a similar
purpose. For clearing the bore-hole the "swab-stick" is employed. This
is a piece of stick small enough to enter the hole and long enough to reach
the bottom. The fibre at one end of the stick is spread out by bruising the
wood. When this is put into the hole the "sludge" passes into the fibrous
brush, and can be brought up. In a few operations the hole is cleaned.
Clay irons" are used for forcing clay into the joints in watery holes, and to
make them dry for using naked powder. This is simply a bar of iron a
little smaller than the bore-hole, with a broad top for striking upon. The
wet hole is charged with tough clay, and the clay iron is driven through it
by a sledge, forcing the clay into all the crevices, so that entrance of water
is stopped. Frequently the entrance of water is thus stopped, but it some-
times fails.
The "shooting-needle" or "nail" is used for forcing a passage through
CHAP. III.]
FOX'S WEDGE FOR BLASTING.
653
the tamping which confines the charge. The introduction of the safety-fuse
for blasting has nearly superseded this process. The "safety-fuse" is
generally made of tape, but often of hemp yarn, guttapercha, or metallic
foil. This is wound up so as to form a small tube, into which is poured a
continuous core of fine powder or priming. A piece of the safety-fuse is put
into the hole, one end penetrating the charge of gunpowder instead of the
needle, and the tamping is rammed in afterwards. The outside end is
ignited, and the fuse becomes a slow train, burning at the rate of about 2 feet
per minute, and it can be cut off sufficiently long for the miner to retire into
security after igniting it. The method of blasting by electricity has been
already explained.
Tamping has been named. This requires the use of a bar of metal to
force the material used into a firm coherent mass above the powder. The
tamping bars are usually of iron or steel; but many accidents have arisen
from their use. Copper rods have been employed with bronze facings, to
avoid the danger of producing a spark by driving iron against a silicious
rock or fragment. Mr. R. W. Fox introduced a wedge for avoiding the
use of tamping. It was very simply made. A branch of a tree, of
a diameter slightly less than that of the hole, is cut into three wedge-
shaped pieces 1, 2, 3, by two cuts of a saw, and a hole drilled through the
central piece from a, Fig. 178. To use this the middle piece is
dropped into the hole upon the powder, and the safety-fuse passed
down to the powder; the side wedges 1 and 2 are then placed in
their correct position and pressed down. No other tamping is
required. The gunpowder exploding exerts an enormous force on
the wedge 3, and the pressure on the rock becomes very great, the
two wedges 1 and 2 resisting the action of the central wedge.
a
2
Beating the borer is generally effected by two men, one of them
holding and moving the borer in the hole, and the other regularly
delivering the blow. Sometimes the operation is carried out by
one man, who delivers the blow with his right hand and moves
the borer with his left one, but this is heavy and very trying Fig. 178.
labour.
The force of the blow for effecting the most advantageous result varies
with the nature of the ground. In dense sharp rock the borer will not bear
such heavy beating as in strata of a tougher kind, such as Killas (Clay-Slate)
or hornblendic Slate. Intelligent miners by experience learn the kind of
blow which is most desirable, and they regulate the strength of the blow to
the description of "country" they are working in.
Much depends on the turning of the borer, which requires some dexterity
to ensure that the holes be kept round and true. The duration of a bit varies
considerably in the hands of different miners. In hard ground some steel
borers will do good service at the cutting end, but stand indifferently under
the blows at the striking end. The wear of various kinds of steel should be
noted, and that selected which gives after trials the best result. Some-
times steel thimbles are driven on to the borers at the striking end to
prevent the wear from the beating. Inferior steel is always disadvan-
The best steel carefully
tageous, and consequently attended by loss.
654
[BOOK III.
PRACTICAL MINING.
sharpened and tempered will be found to be always in the long run
the most economical.
Bits vary considerably, according to the character of the rock upon which
they are to be employed. It would not be satisfactory to describe the
varied forms of the cutting edges of borers without drawings of them, and
even then the miner or the smith would scarcely be guided satisfactorily.
Experience gained by carefully noting the results obtained under different
conditions is the only reliable guide for the miner.
Hammers and Sledges.-When a tool of this kind is furnished with a metal
head and is intended to be used with one hand it is called a hammer. When
it is to be used with both hands it is
named a sledge. (Wooden-headed
tools are commonly called sledges,
and sometimes mallets.)
Fig. 179.
Hammers scarcely require de-
scription, the varieties are so gene-
rally well known. They vary in
shape in different localities. In the
St. Just mining district the miners
are very expert in single-hand bor-
ing, and they use a hammer with a
long bloat-head with a little sweep,
Fig. 179. In another part of Cornwall they use what are called "cat's-head”
hammers; these have short, broad, bully heads, with the panes sharply
chamfered down to the size of a halfpenny. This shape secures the
miner turning the borer from a blow if the hammer glances aside. This
tool is shown on Fig. 180.
00
Fig. 180.
Fig. 181.
Fig. 182.
The boring mallet has a head usually made of a block of elm.
Single-hand boring hammers weigh from 2 lbs. to 4 lbs.
Sledges for double-hand boring weigh from 4 lbs. to 10 lbs.
The handles of boring hammers are from 6 inches to 18 inches long.
The handles of boring sledges are from 18 inches to 30 inches.
Sledges are frequently used for breaking up lumps, and for this purpose
CHAP. III.]
THE MINER'S PICK.
655
'lump-sledges" are used, the weight of the head varying from 10 lbs. to
20 lbs.
In the dressing of ores various hammers are employed. The "cobbing
hammer" is shaped as in Fig. 181, the head varying from 14 to 18 inches
long and weighing from 2 lbs. to 4 lbs.
The "bucking hammer" (Fig. 182) or "Iron" is a striking plate of iron,
with a stirrup to receive the handle, which is secured by a wooden wedge
driven in the back of the plate. Rollers and crushing machinery are
gradually superseding these hammers.
Picks.—These are instruments which are essentially the miner's tools.
They are of great antiquity, being represented on the Egyptian and Assyrian
monuments, found in the grave-mounds of the earliest races who inhabited
Europe, and in the mines worked by the Romans. They pass by different
names in various districts, as "pikes," "slitters," "mattocks," "hacks," and
"mandrels."
The pick-head is usually of wrought iron with steel tips. An
An eye is
formed in its centre to receive the handle or helve, which is generally secured
by a wedge.
The action of a pick is to penetrate, chip, or break up by rending the
mineral substance upon which it is used. Picks are used with advantage
in working jointed, shaly, or fissured rock. The force of the blow, which is
regulated by the blow urged by the miner, expends itself in making the point
of the pick penetrate the ground, and thus loosen it. It is also of value
as a bent lever. When it has entered the ground the pick forms its own
fulcrum and acts like a crow-bar. It thus affords the most convenient tool
Fig. 183.
for levering the ground. It is also employed as a scraper for dragging out
the stuff loosened by working, Fig. 183. The weights of picks vary in dif-
ferent districts, and the shape is determined by the nature of the material
upon which it is to be employed. The picks used in metal mines and
those employed in collieries differ considerably. The "poll-pick" is much
used in Cornwall, in Derbyshire, in Flintshire, and other mining districts.
It differs from ordinary picks which have two stems, by having one
656
[BOOK III.
PRACTICAL MINING.
about 12 inches long and a stump, forming the "poll," about 3 inches long.
The face of the poll is steeled like a hammer, so that it can be used for
striking blows. The length of the handle or "helve" is generally from 26
to 28 inches; it is slightly curved and feathered on one side only.
The poll-pick can be used both as a pick and a sledge. It is sometimes
used as a wedge, and by carefully striking it on the poll end it does this
effectively, but if the poll is struck too heavily the eye of the pick is liable to
burst. If the pick is used too severely it is liable to “wince "—that is, to
alter the adjustment of the handle. The mischief of "wincing" can be
avoided to a great extent by increasing the end-bearing surface of the eye.
In some cases corbel bits are welded at the ends of the eye. To avoid this
the ends of the eye should be made as deep as possible in the direction of
the helve, in order to give the feather, when prizing, fulcrum as far as possible
from the neutral axis of the head.
Shovels, Spades.-In the historical sketch some illustrations have been
given of the shovels used by the ancient miners. They are, therefore, of very
high antiquity. Without the shovel the earth mounds could not have been
formed, nor the earthworks of old fortifications constructed. The principle
of the ordinary shovel is that the plate shall be of iron, with steel around the
front edges, or "mouth." It is furnished with two "straps," or "ears," to
receive the helve, which should be made of ash. The plate is a little dished;
it is slightly concave on the top surface, which is caused by the sloping of the
back and sides, by which firmness is secured, and the plate sustains its load
more securely. The long-handled shovel is used in Devon and Cornwall;
in most other districts the shorter handle is furnished with a crutch.
The Vanning shovel of the tin-miner, to be effective, should be carefully
made. The plate is generally larger than the gravel shovel; and as it is not
used for any heavy work it need not be so thick, and is consequently lighter.
The curved surface of the dish should be nicely adjusted to insure the separa-
tion of the "edge of tin" from the coarser stuff, which is to be washed away.
There are many tools employed in the process of mining which do not
require description in this volume. In the process of timbering the shafts or
the levels, hatchets, axes, and adzes are used, and saws of various kinds; but
these belong to the engineering department or to the carpenter, and have no
especial peculiarity as mining implements.
There are a few tools which are still used by the old miners, but
which are gradually being superseded by the more modern arrangements,
which must be named. For example, "gads." These are made of wrought-
iron; when they have a point they are termed gads, when made with a
chisel edge they are wedges. These vary much in size, the length being
from 3 inches to 2 feet, but as a general rule they are from 6 inches to 1 foot.
Frequently a tongue of steel is welded in to the iron to form a point, and
often the striking end is faced with steel. By far the best arrangement is to
make the gad entirely of steel. The "Saxon gad" has an eye near the
middle, so that a number can be placed on a rope by the miner when pro-
ceeding to his work. Gads are much used in working "vuggy" or hollow
ground, and on such rocks as are jointed. For this purpose such as are made
of shear steel should be employed.
Wedges are more extensively used in collieries than in metal mines. An
CHAP. III.]
SUBTERRANEAN SURVEYING.
657
arrangement called "plug and feathers" is sometimes employed for breaking
out large blocks of mineral ore. For this, a hole is bored, and two inverted
wedges with circular backs are placed in the hole, then a driving wedge or
plug is driven in between them to break out the mass. The wedges and
gads being often lost, through neglect on the part of the miner, who should
search them out of the broken material in which they are often buried, it is
now a common practice to charge the miner for the steel which is lost.
7
"Pickers" and "pokers," which are made of -inch round iron with steel
tops, are used for working in jointed ground and in thin veins. For clearing
clay joints they are very important, and in St. Just, where thin veins of tin
are very common, these tools are much used. The miners of St. Just use
the pickers very dexterously, and they can often be distinguished from other
miners by a horny mark on the back of the little finger on the left hand,
which is caused by holding it under the haft of the picker for keeping up the
point. These tools are held by the miners in one hand, and struck by a
hammer with the other.
The “set” or “moil" is used for cutting ground where it requires to be
done evenly, as in cutting “hitches" or preparing “seatings" for pit-work or
the like. The "set" is shaped like a poker, and when intended for single-
hand use, they weigh about 4 lbs. In many cases they are made much
heavier, and then they are called "double-hand sets," and in many respects.
resemble borers.. Bars-as "socket bars," or "beche," "crow bars," and
"pinch bars”—are useful for levering out ground, and for splitting rocks
traversed by cleavage planes.
Especial attention should in every case be given to the quality of the iron
or steel which is employed in mining implements, and of the wood which is
used to form the handles of picks, shovels, and other mining tools. It is
always the truest economy to employ the most perfect metal and the best
selected pieces of ash for the handles and helves of shovels and picks.
MINE SURVEYING.-A thorough familiarity with the principles of under-
ground surveying is of the utmost value in the education of a miner. It may
appear to many that he has but to sink a hole from the surface down to the
mineral lode, and then to break out the ore, following the lode wherever it
may lead him. Without doubt this was, in the early days of mining, the
practice of the untaught man, who could only sink his shaft a few fathoms in
depth, and drive his level for but short distances, by reason of the gathering
of water in the shallow workings. Experience taught the miner the advan-
tage of adopting some principle which would enable him, having sunk a
vertical shaft on the side of a hill, to cut from the bottom of the hill, a level,
or adit, which should reach the deepest point of the shaft, and thus drain
all above that point of the accumulated waters. It was an ancient practice
to mark out upon the surface the line from the mouth of the shaft to the lowest
ground. This guided the miner in cutting the level through which the water
should flow.
As mining operations became more and more complicated by the exten-
sion of the levels, and especially by the driving of levels at different depths
upon the lode-which levels were connected by winzes-the necessity for a
careful survey increased.
658
[BOOK III.
PRACTICAL MINING,
The most reliable guide to the surveyor is the compass-needle-a bar of
iron or steel rendered magnetic-possessing the property-when suspended
being free to move-of placing itself in a constant direction. One end of
this bar always points towards what we term the north pole of the Earth,
and the other to its south pole. The magnetic bar furnishes the means of
determining, under all the usual conditions, a fixed line, from which the
positions of any other line can be readily determined. This electrical bar
is called the magnetic-needle, and when it is fixed on a delicate pivot upon.
which it is free to move, beneath which is a circular card divided into 360
degrees, we have the surveyors' or the mariners' compass.
The graduated card of this instrument is divided into the four cardinal
points-North, South, East, West. The two first-north and south—are the
line where the meridian cuts the horizon. The points of the line east and
west are each 90° distant from the points north and south, therefore the
circle is divided into four equal parts of 90° each.
The magnetic force manifests itself, on the surface of our globe, by three
classes of phenomena. The declination of the magnetised bar, its inclina-
tion, and the intensity with which the terrestrial force acts on the needle.
The declination is the angle that is formed with the direction of the
meridian of the plane by the direction of a magnetised needle placed upon
a vertical point or suspended by a thread, free of torsion, in such a manner
that it holds itself horizontal.
The inclination is the angle formed with the horizon in the magnetic
meridian by the direction of a magnetised needle sustained by its centre of
gravity, around which it is able to turn in a vertical plane. These three
elements—declination, inclination, and intensity-vary, not only from one
place to another, but in the same place with time. The point of the needle
which is directed towards the north has been termed the north pole, and that
which is directed to the south the south pole. The direction of the magnetic-
needle is so constant that even when the needle is drawn aside it always
returns to its original position, and it is always the same extremity of the
needle which is turned towards the north. The direction of the magnetic-
needle is constant for the same place and for a given epoch. It is also sub-
ject, on the same point of the globe, to small periodic variations during the
day, which have been termed diurnal variations.
The direction is not exactly north and south. The plane that passes
through the centre of the Earth in the direction of the magnetic-needle, in
any place under consideration, is termed the magnetic meridian, to distinguish
it from the terrestrial meridian, which is the plane passing through the same
place and the axis of the earth.
The angle made by these two planes is termed the declination of the
magnet. The declination is east and west of the terrestrial meridian. The
difference between the magnetic and the true meridian at different periods
in London has been as follows:
In 1576 it was
From 1657 to 1662
In 16,0
In 1815
In 1849
In 1883 it is
11° 15' to the east.
O
2º 6′ to the west.
•
24° 2' 18"
""
22° 35'
""
•
18° 15′
(maximum direction.)
CHAP. III.]
THE VARIATION OF THE NEEDLE.
659
It is necessary in all mining surveys to note the variation of the needle
at the time the survey is made. The lines on a mining plan which indicate
the direction of the workings in 1883 will, unless they have been corrected,
-in twenty years,-deviate considerably from the lines drawn.
To determine the variation, a magnetic-needle, delicately suspended, is
used. A carefully divided circle, upon which is read the division corre-
sponding with the extremities of the needle, is fixed against the sides of a
circular box of copper and covered with glass, in which box the needle,
resting on its point, is placed. Delicate instruments are furnished with a
telescope carried on an axis of rotation, parallel to the plane of the circular
division, and the middle of which is upon the vertical that passes through
the centre of suspension of the needle. The axis carries an air-level and a
vertical quadrant divided to measure the angles described by the telescope.
The box is turned round upon a vertical axis, by which it is fixed upon
its stand, until the telescope is found to be placed in the direction of the
meridian. The angle made by the direction of the telescope with the direction
of the magnetic-needle is then determined, and we obtain the declination.
If we know the declination (which is regularly published in the “Nautical
Almanack," as determined by the Astronomer-Royal and copied into most
other almanacks) we turn the box until the angle made by the axis of the
telescope and the direction of the needle are equal to it, then we have the
position of the meridian.
With the inclination or dip of the needle the miner has little to do, and
the magnetic bar in the miner's compass is so adjusted as to be independent
of the Earth's attractive magnetic power.
The force which we call magnetism appears to have been discovered at an
early period in Greece. The name is supposed to have been derived from the
province of Magnesia, in which a stone (magnetic iron ore) was first found by
a shepherd. It is said by the Chinese that they used the magnet in the year
121 of the Christian era. Another Chinese authority tells us that under
the dynasty of Tsin, 419 years before Christ, vessels were directed towards
the south by means of the magnet. Vasco de Gama appears to have
employed the magnet in his first expedition to India. The discovery of the
declination of the needle was made by Christopher Columbus: the change
of declination, in the same place, was discovered by Gunter, a professor in
Gresham College; and the dip was first observed by Normann in 1576.
With this introduction we proceed to describe the processes of subter-
ranean surveying.
It
Amongst the instruments used the circumferentor is important.
consists of an horizontal circular plate with a graduated circle of degrees
numbered from 0° to 360°, and a vernier, by which these primary divisions
are subdivided to single minutes. The Theodolite is a delicate instrument
of much value for measuring angles, and Gunter's chain is a simple measure
of length, which is used in coal mines: it contains 100 links. A chain is
now used in the metal mines of Derbyshire and Cornwall which is divided
into 100 feet.
It is essential that the mine surveyor should thoroughly understand and
use the best instruments. The following are the most important :—
UU
660
[BOOK III.
PRACTICAL MINING.
The Y level, in ordinary use, consists of a telescope resting upon two
supporters, which are commonly from their shape called Y's. The lower
ends of these supporters are let perpendicularly into a strong bar, which
carries the compass-box. This compass-box is convenient for taking
bearings, and has a contrivance for throwing the needle off its centre.
One of the Y supporters is fitted into a socket, and can be raised or lowered
by a screw. Beneath the compass-box is a conical axis passing through
the upper of two parallel plates, and terminating in a ball supported in a
socket. Immediately above this upper parallel plate is a collar, which by
turning the clamping screw is made to embrace the conical axis. A slow
horizontal motion may then be given to the instrument by means of a
tangent screw. A spirit-level is fixed to the telescope by a joint at one end
and a capstan-headed screw at the other, to raise or depress it for adjust-
ment. The telescope embraces a large field of view, but the measurements
required will only refer to one particular part, which is always the centre of
the field of view. Some fixed point must be placed on the field of view at the
focus of the eye-piece. Two fixed lines furnish such a point, and those are
furnished by two spider's threads fixed at right angles to each other in the
focus of the eye-piece. These are attached by some cement to a brass ring
of smaller dimensions than the tube of the telescope, which can be fixed by
means of four small screws.
The adjustment of the level will require close attention to rules, which the
கண
R
て
​Z
I
H
R
O O
F
G
Fig. 184.
I
B
mine surveyor can ob-
tain from several works
devoted to this art.*
For mining opera-
tions, instruments
adapted to measure the
rise or fall of each 100
feet of distance are con-
venient.
The level repre-
sented (Fig. 184) is a
particularly useful one.
The telescope A B is
attached at the object-
end to the bar CD by
the hinge-joint H, and
this bar is attached
to a second bar, F,
by the spring k and
the pivot p. The bar F
screws on to an axis G, fitted to the head of a tripod stand, and the bar
CD being approximately levelled by moving the legs of the stand, is brought
truly horizontal by turning the screw S until the level comes to the centre of
*See especially J. F. Heather's "Mathematical Instruments." There is a small original edition and
another enlarged edition in 3 vols. T. Baker, C.E., "Land and Engineering Surveying," and his "Sub-
terraneous Surveying." Crosby Lockwood & Co.

CHAP. III.]
THE MINER'S THEODOLITE.
661
its rim. The eye-end A of the telescope is attached to the bar CD by the arc
RR, and is moved along this arc by means of a rack and pinion moved by
the screw T. The arc RR is graduated to show the rise and fall in every
100 feet, and is read by means of an index seen through the small circular
opening e. The bubble in the level is adjusted by the capstan-headed screw.
The Miners' Dial is an instrument especially adapted for subterranean
surveying. It may be used as a plain theodolite at any station, without
disturbing the work done by means of the compass-needle, or altering the
form of entries in the levelling-book. This instrument has been the object
of very great attention in Cornwall; and amongst others, Mr. Wilton, mathe-
matical instrument maker, of St. Day, near Redruth, made many important
improvements. Wilton's Improved Miners' Dial is so constructed that it may
be used as a common dial,-as a theodolite without a vertical arc,-or a tele-
scope, or a theodolite to which a telescope, and vertical arc, may be attached.
This dial has been subjected to yet further and more recent improvements by
Mr. Edward T. Newton, Mr. Wilton's son-in-law and successor, now of
Camborne, Cornwall.
The Theodolite.-This instrument may be considered as consisting of three
parts-the parallel plates, with adjusting screws fitting on to the staff-head,
of exactly the same construction as
already described, for supporting the
Y and other levels; the horizontal
limb, for measuring the horizontal
angles; and the vertical limb, for
measuring the vertical angles, or
angles of elevation, Fig. 185.
The horizontal limb is com-
posed of two circular plates, I and V,
which fit accurately one upon the
other. The lower plate projects
beyond the other, and its projecting
edge is sloped off, or chamfered, as
it is called, and graduated at every
half-degree. The upper plate is
called the vernier plate, and has
portions of its edge chamfered off,
so as to form with the chamfered
edge of the lower plate continued
portions of the same conical surface.
These chamfered portions of the
upper plate are graduated to form
the verniers, by which the limb is
subdivided to single minutes. The
L
N
B
S
S
Fig. 185.
N
6-inch theodolite represented in our figure has two such verniers 180° apart.
The lower plate of the horizontal limb is attached to a conical axis passing
through the upper parallel plate, and terminating in a ball fitting in a socket
upon the lower parallel plate, exactly as the vertical axis of the Y level
already described. This axis is, however, hollowed to receive a similar
UU 2
662
[BOOK III.
PRACTICAL MINING.
conical axis ground accurately to fit it, so that the axes of the two cones may
be exactly coincident or parallel. To the internal axis the upper or vernier
plate of the horizontal limb is attached, and thus while the whole limb can
be moved through any horizontal angle desired, the upper plate only can also
be moved through any desired angle, when the lower plate is fixed by means
of the clamping screw G, which tightens the collar D. T is a slow-motion
screw, which moves the whole limb through a small space to adjust it more
perfectly after tightening the collar D by the clamping screw C. There is
also a clamping screw c for fixing the upper or vernier plate to the lower
plate, and a tangent screw t for giving the vernier plate a slow motion upon
the lower plate when so clamped. Two spirit levels B B are placed upon
the horizontal limb at right angles to each other, and a compass G is also
placed upon it in the centre between the supports F F for the vertical limb.
The vertical limb N N is divided upon one side, at every 30 minutes
each way, from o° to 90°, and subdivided by the vernier, which is fixed to the
compass-box, to single minutes. Upon the other side are marked the number
of links to be deducted from each chain for various angles of inclination, in
order to reduce the distances as measured along ground, rising or falling at
these angles, to the corresponding horizontal distances. The axis of this
limb must rest in a position truly parallel to the horizontal limb upon the
supports F F so as to be horizontal when the horizontal limb is set truly level,
and the plane of the vertical limb should be accurately perpendicular to its
axis. To the top of the limb N N is attached a bar, which carries two Y's for
supporting a telescope of the same construction as that before described for
the Y spirit level; and underneath the telescope is a spirit level SS attached
to it at one end by a joint and at the other end by a capstan-headed screw,
as in the Y level. The horizontal axis can be fixed by a clamping screw,
and the vertical limb can then be moved through a small space by a slow-
motion screw i
Before commencing observations with this instrument, the following
adjustments must be attended to:-
1. Adjustment of the telescope, viz. the adjustment for parallax; the
adjustment for collimation.
2. Adjustment of the horizontal limb, viz. to set the levels on the horizontal
limb to indicate the verticality of the azimuthal axis.
3. Adjustment of the vertical limb, viz. to set the level beneath the
telescope to indicate the horizontality of the line of collimation.
Newton's Combined Miners' Dial-Theodolite-and Dumpy Level consists of
a 6-inch compass-box, the levels being inside. On the face of the dial are
two verniers reading to minutes. The improvement in this dial consists of
an arrangement by which the bearings are taken simultaneously with loose
needle and vernier, the latter automatically checking the former; thus any
error arising from incorrect reading or from local attraction is detected.
The dial has a quadrant with a large and powerful telescope for surface sur-
veying; the telescope being movable can be replaced by a pair of sights for
underground surveys; the dial has also a pair of sights for dialling. On
removing the quadrant from the dial the telescope can be put on the dial, it
can then be used as a dumpy level. The quadrant is so constructed that the
face of the dial is always clear for reading the needle and vernier. It is
CHAP. III.]
SURVEYING WITH NEWTON'S DIAL.
663
graduated on one side into degrees and half-degrees vernier reading to
minutes, on the other side into feet and inches.* An extra set of legs with
candle reader also fits the dial; by its use it enables the dialler to take his
bearings with greater dispatch and accuracy.
Instructions for commencing a Line of Survey with Newton's Dial, with
Two Sets of Legs and Candle Reader.-Place the dial on its legs at first
station; get the levels right by means of the ball and adjusting screws; see
that the vernier on the face of the dial is clamped to 360°, then get the needle
to read to 360°; then screw the dial tight on the legs with the socket screw;
place the other set of legs in position at second station; get the levels on
the candle reader right, then set the vernier free on the face of the dial by
unscrewing the long clamp screw; move the dial round until the sight inter-
sects the candle reader at second station; read angle by needle and vernier;
then measure the distance. Clamp the vernier and take off the dial from
the legs at first station, and fix it on legs at second station; with the candle
reader on the legs at first station, take a back draft, then remove the legs
from first station and fix them at third. The needle and vernier will
read alike in any draft, unless there should be iron in the way; then the
vernier at once checks the needle, and gives the proper bearing. The miner
can go on with his survey as if using the common miner's dial, the vernier
correcting any error in reading the needle-always remembering to take a
back draft with vernier clamped at last angle.
Instructions to commence a Line of Survey where the Needle is rendered
useless from the Vicinity of Iron.-Fix the dial on its stand and get it level
at the second station, with vernier at 360°, and take a back observation, the
other stand and candle reader being the object on first station. Screw the
instrument tight on its stand, then measure the distance; this forms the first
draft. Remove the stand with candle reader to third station, get it level,
then take a fore observation by unscrewing the clamp screw of the vernier,
which sets it free; then revolve the dial until it intersects the candle reader
at third station, measure the line and enter this distance, also the angle now
indicated by the vernier; place the dial on the legs at third station; loosen
the dial on its legs so that the whole instrument shall revolve, with vernier
clamped at last angle. Move the dial until it intersects the candle reader by
back observation again. Take a fore observation by screwing the dial tight
on its legs and unscrewing clamp screw of vernier, revolving the dial until
it intersects the candle reader at fourth station; measure the distance and
angle by vernier. In this manner any number of observations may be taken,
always remembering to take a first back observation with the vernier at the
angle last read. By this means the miner will be enabled to continue the work
from the same meridian-that is, the zero of the instrument at the close of
the survey will have the same direction that it had at the commencement.
All angles thus taken on the number of degrees indicated by vernier should
be entered as if taken by needle. The work may be laid down by protractor
and scales as if surveyed by needle. If, however, it be desirable to ascer-
tain the direction of the survey with regard to the magnetic meridian, this
may be done as follows:-Having the angle as before, at any convenient
station, the vernier at 360° and clamped there, set the needle free and direct
* See Appendix for Table showing the underlies and perpendicular to every degree of the quadrant.
664
[BOOK III.
PRACTICAL MINING.
the sight along the same line; enter the angle indicated by the needle: this
will give the angle for the north as required. The work can be resumed by
needle or vernier, and completed with either. From the bearing of the line
thus obtained, the magnetic meridian may be set off on the plan by placing
the protractor so that the angle taken by the needle may coincide with the
angle of the same draft taken by vernier; then marking the position of the
zero of the protractor, a straight line drawn through that point and the
centre of the protractor will be the meridian. If, however, it be required to
lay down the work on a plan in which the meridian is already determined
with a protractor, the same graduations will do for both needle and
vernier. Place the protractor on the meridian of the plan, with the 360°
towards the north; mark the centre of the protractor and the degrees indi-
cated by the needle at the given draft from the proper graduation for needle,
remove the protractor and place it again on the same centre, with the angle
taken by the vernier at the same station. The zero of the protractor will
now bear the same relation to the meridian of the plan that the first line of
survey did to the magnetic meridian, and that all the angles of the survey
are taken from the first line as a meridian. They may now be marked off
from the protractor in this position in the usual way.
Angles taken in the manner described may be reduced to angles from the
north by the following rules-having the angle by vernier at any station, and
the angle by needle at the same station :—
Rule I.—Subtract angle by vernier at any station from angle by needle at
the same station; the difference is the angle of first draft from the north,
but if the angle of vernier exceeds the angle taken by the needle, add 360°
to the latter and subtract the angle by vernier. The remainder is the angle
from the north. Add every subsequent angle by vernier to the angle by
needle, as obtained above; the sum is the angle made by the corresponding
draft with the north. If, however, such sum is greater than 360°, subtract
that number from it; the remainder is the angle from the north as required.
Rule II.-If the last angle by vernier be less than the preceding angle
add their difference to angle by needle; the sum will be the angle from
the north; if such sum is greater than 360°, subtract that number from it;
the remainder is the angle from the north.
If the last angle by vernier be greater than the preceding angle, subtract
their difference from angle by needle; the remainder will be the angle from
the north; but if the difference between the two angles be greater than the
angle taken by the needle, add 360° to that angle and subtract the difference;
the remainder will be the angle from the north.
This ingenious mathematical instrument maker has recently introduced a
small portable dial and quadrant, which by its simplicity and portability
strongly recommends itself to the intelligent miner.
This little instrument has 3-inch compass-box divided similar to a large
dial, it has two levels at right angles, and folding sights. The quadrant is
fixed under the dial in using the instrument. When fixed on the legs
it revolves on a shank similar to a larger one; there is a clamp screw
attached to the quadrant which by unscrewing a turn or two sets the quadrant
free and enables the user to take the elevation or depression. On bringing the
CHAP. III.]
THE TRANSIT INSTRUMENT.
665'
quadrant back to zero, the needle of the dial at once gives the bearing. The
legs are made to fold up, and when closed are just the size of a good walking-
stick, and can be used as such. The instrument is complete in itself and is
fitted into a nice mahogany case.
For subterranean work, the altitude or depression of any point may be
ascertained by means of the theodolite attached to the circumferentor. This
may also be used for surface levelling, either by taking the angles of elevation
or depression or by fixing the quadrant at zero and using the instrument as
a spirit level.
With the levelling instrument the altitude of any place is determined by
fixing it at any convenient situation, to command a back sight to the staff at
the commencement of the line of operation, and a fore sight to the next
station. The difference between the staff readings will be the difference of
the level of the two points.*
D
H
I
F
α
The Transit Instrument.-The transit instrument is a standard one in
every astronomical observa-
tory, where it is used to
define a vertical circle pass-
ing from the north to the
south point of the zenith of
the place. It is equally
useful to find any number of
points in a straight line
connecting two given points
in mining or in land sur-
veying.
C
Fig. 186.
The line thus connecting
the distant points is the
base of a vertical plane of
small extent. The telescope
A A, Fig. 186, is made to
revolve vertically upon an
horizontal axis B B, the
pivots of which are sup-
ported by the upright arms
CC of the iron stand. The telescope resembles those of theodolites and
spirit levels, and for mining or railway surveying purposes it is supplied
with a system of cross wires. The intersection of the centre wires with each
other represents, when in proper adjustment, the line of collimation or optical
axis of the telescope. The slide D, or eye-piece, is movable in or out to
obtain distinct vision of the cross wires; an adjustment that must be made
or verified each time the instrument is set up for use. In adjusting the
eye-piece to obtain distinct vision of the wires it will be found that it can be
accomplished with greater certainty by directing the telescope to a white
sheet of paper fastened at a little distance off. The screw E gives motion to
* For practical purposes the miner may consult J. Budge's "Practical Miner's Guide," Longman,
Green, & Co.; Thomas Fenwick and Thomas Baker, "Subterraneous Surveying," Crosby Lockwood
& Co.; William Rickard, "The Miner's Manual," Longman & Co.
666
[BOOK III.
PRACTICAL MINING.
a rack and pinion, which is the means of diminishing or increasing the
distance between the object-glass and the eye-piece.
That the horizontal axis may not be liable to bend with the weight of the
telescope, it is made of two cones B B, whose bases are connected together to
form the axis, and to the telescope by the sphere F, which form the nucleus
of the instrument to which the tubes A A', forming the telescope, and the two
cones B B are attached. The apex of each cone is finished with a steel or
bell-metal pivot turned and ground upon the axis as true as possible. These
pivots work in V-formed sockets or Y's as they are technically called, which
surmount the upright arms CC of the iron stand.
H is a spirit level striding across the instrument. This is used to deter-
mine the horizontality of the instrument. One or two thin brass plates are
supplied. These are notched at their tops to receive a pin fixed in the end
of the tube of the level H, to prevent its falling. The iron stand is fastened
to the stone after it is placed in its true position by means of the screws
K K.
To set the axis of the telescope truly horizontal, adjust the level H upon
the pivots of the axis, and by turning a milled-headed screw a near the top
of one of the arms. Any error must be corrected by raising or depressing
the screw a on the stand, and by turning the capstan screws b at one end of
the level, which raises or depresses the spirit-bubble with respect to its
points of support. These rules are sufficient for the mining engineer, but
for astronomical purposes more refined adjustment is required. When the
position of the instrument has been settled, the screws K K are inserted in
their sockets through the holes in the stand. Thus a very close approxima-
tion can be secured.
To make the subject of mine-surveying as comprehensive as possible,
the following directions should be strictly attended to :-
Dialling with the Magnetic Needle.-Assuming that the ordinary dial is
employed, the operator in commencing a survey fixes the tripod firmly, and
then, guided by the spirit levels, carefully adjusts the instrument, either by
the ball and socket joint or the adjusting screws, until the bubbles are
centred. The dial-plate is then turned around until the south end of the
needle (always distinguished) settles at o° or 360°. Should the needle be
sluggish, a gentle tap to the plate will cause a quivering and facilitate its
progress to its proper position. Having clamped the instrument securely to
the tripod, an angle can now be taken in any required direction by moving
the sights around with the large thumb-screw. Having taken the observa-
tion, the degree on the inner graduated circle opposite the arrow on the
vernier scale is recorded, together with the minutes which may be indicated
by the same scale. Some practitioners read off the angle recorded by the
north end of the needle, the movable sights being previously fastened at zero.
But inasmuch as the above method should be adopted in dialling without the
needle, and being equally as expeditious and more accurate in taking frac-
tional parts of a degree, the advantage of uniformly observing it is apparent.
Let A, Fig. 187, represent a shaft, and BCDE a subterraneous excavation
in a northerly direction from it, the bearings of which are required. Having
made sure that there is no iron near him, the dialler fixes his instrument
CHAP. III.]
DIALLING WITHOUT THE NEEDLE.
667
at B, to command two drafts. The plate is put into the position before
described, and a back observation taken to A, and the degree indicated by
the arrow in the vernier (which
B
D
E
Fig. 187.
in this case, being a northerly
drift, will be on the north side) is
the direction of A B. The dialler
then reverses his position, and
takes a fore observation to C; the degree is read off, and this gives the
course of B C. The next position for the dial is at D, the object at C
being allowed to remain until the angle DC is determined. The previous
operation to ascertain the direction of D E is repeated, and the survey
terminates.
Dialling without the Needle.—It is well known that the magnetic-needle is
disturbed by the influence of iron, and is consequently rendered unreliable by
its presence. Serious errors having been, from time to time, fallen into by the
counter attraction this metal offers, a system has been devised by which the
magnetic-needle can be dispensed with, after a datum line has been obtained.
The dial is carefully fixed in the manner already described, and the movable
sights directed towards the objects stationed at the commencement of the
survey. This should be a "candle rest" with spirit levels, and adjusting
screws, mounted on a tripod, of precisely the same size and description as
that on which the dial stands. The angle which the index or vernier records
with the circular plate is then observed, and the dial unclamped and removed
to the position occupied by the candle rest, and it is transferred to the dial
tripod. The movable sights are kept in the same position, and the dial-plate
moved around on its axis, until the candle at the first station of the dial is
bisected. The circular plate is then rigidly clamped by the screw, and the
instrument is ready to take an angle independently of the needle.
Whatever departure the needle may show from the north point is due
to attraction, for, provided proper care has been exercised in the operation,
the dial-plate will correctly indicate the magnetic meridian, and virtually
supersede the needle throughout the whole survey. Occasionally the whole
dialling may be verified by the last draft being out of the influence of iron,
for if the south point of the needle corresponds with that on the circular plate
its correctness is demonstrated.
In conducting a survey without the use of the needle, the instrument
must be fixed at each respective station, and fore and back sights be taken
alternately. The operation will be, rendered clearer by the following
example.
The direction and distances of the subterranean drift, containing iron rails
and pipes, are required. To obtain a datum line the dial is fixed in a recess,
or a section of the rails and pipes must be removed. The instructions pre-
viously given having been strictly observed, the sights are directed to the
candle rest at A, and the degree (say 40°) carefully noted, but not permanently
entered. Reversing the position of the instrument and candle rest, the dial-
plate is moved round, with the sights still at 40°, until it bisects the candle.
This gives the datum line correctly. The plate is then securely fastened,
and the sights directed to B, which the vernier shows to be 10° distance, by
668
[BOOK III.
PRACTICAL MINING.
measurement 30 feet. The dial is then carried forward to the next post of
observation B, the tripod on which it stood being allowed to remain undis-
turbed, for fixing the candle socket on, and with the sights still retained at
10°, the whole instrument is moved bodily around, until the perpendicular
hair cuts the candle at A. This back observation being taken to keep the
line of the magnetic meridian only, the angle is not recorded. The candle
rest and tripod are now advanced to C, and the rack work controlling the
movable sights of the dial brought into operation for ascertaining the angle
from B to C, which by reference to the vernier we find is 1º, distance 50 feet.
The position of the instrument and candle rest is again changed, and the
preliminaries being attended to, the course from C to D is determined; this
is 15° 35', distance 35 feet 6 inches. We proceed in the same way to the
station D, and get the direction of D E, which is 20° 45', distance 29 feet
9 inches. This is the termination of the excavation. An opportunity may
now be afforded, and the dialler should invariably avail himself of it, for
testing the correctness of the survey.
FAULTS-THEIR INFLUENCE, &C.
I
Method of determining the Influence of Faults on Lodes.-In the section
which is devoted to the consideration of mineral lodes and their formation,
the subject of dislocations has not been neglected. It has now become
necessary to examine the circumstance under which these fractures occur, and .
the rules by which the miner should be guided in his endeavours to recover
that portion of any lode which has suffered by these disturbances.
The provincialisms employed to express the phenomena exhibited, as the
results of movements in the rocks in which mineral lodes are found, should
be thoroughly known. The following vocabulary, which is given by Mr. W. J.
Henwood, should therefore be clearly understood:-
1. The rocks, whatever may be their character, are denominated
2. All metalliferous veins.
3. All veins, not metalliferous, and in directions subtending considerable angles
to those which are productive
4. Horizontal galleries, if excavated in metalliferous veins
5. Ditto, ditto, not in metal veins
6. Pits open to surface
•
7. Pits not open to surface, but extending on the dip of a vein from one gallery
(level) to another
•
The Country.
Lodes.
Cross Courses.
Levels.
Cross Cuts.
Shafts.
8. All excavations horizontally
•
9. Ditto downwards
10. Ditto upwards
II. Small veins, whether metalliferous or otherwise (in St. Just)
•
Winzes.
Driving.
Sinking.
•
Rising.
Scorrans.
The following terms are derived from other sources, and are used in
Derbyshire and the Northern counties:-
a. The beginning of a shaft, on the very surface
b. When a dislocation comes slanting in before the miner as he cuts or sinks
c. When a dislocation runs along in the vein
d. When a vein is dislocated and moved.
•
e. If two veins or pipes cross one another "right," or obliquely
•
The Eye of
Slip-joint.
Rider-joint.
•
•
•
A Leap.
A Pee, or a Tyc.
In the Miners' Glossary, given in the Appendix, a number of other
provincial words and Mining terms will be found.
Every intersection must be, either a simple running of one vein through
another, or, a movement of the rocks producing what the miners call a heave,
CHAP. III.]
THE DISLOCATION OF LODES.
669
or, in ordinary language, a displacement. If the lode is discovered by driving
to the right on the cross vein, it is called a right-hand heave, but if it is
approached on the left it is a left-hand heave. It will be readily understood
that if a lode runs east and west through any rock, and if that rock suffers
any disturbance, by which one portion of the rock is raised or falls down,
that the lode will suffer a heave or a slide.
Of
Mr. Henwood has recorded 272 intersections observed by himself.
these 57 were unaccompanied by heaves; 181, or more than 84 per cent.,
were found by driving on the side of the greater angle; and 34, or less than
16 per cent., were on the side of the smaller angle. He gives the following
table :-
Of all the lodes, the proportion intersected but not heaved is
Of the tin lodes
Of lodes yielding both tin and copper
Of copper lodes
Of all the lodes the proportion heaved towards the right hand is
Of the tin lodes
Of the lodes yielding both copper and tin
Of the copper lodes
Of all the lodes the proportion heaved towards the left hand is
Of tin lodes
•
Of lodes yielding both tin and copper
Of copper lodes
Of all the lodes the proportion heaved towards the greater angle is
Of the tin lodes
•
27.7 per cent.
18.0
""
•
37.2
17:7
•
51.1
""
•
56.0
44.0
""
•
52°4
26.2
•
26.0
18.6
""
29.8
",
63.5
""
52.0
•
56.0
•
74.2
•
12.9
•
30.0
""
6.8
""
8.8
""
16.4 feet.
tin lodes
•
lodes yielding both tin and copper ore
copper lodes
15.4
14.6
17.5
The mean distance of the right-hand heaves is
18.7
left-hand
12.0
heaves towards the greater angle
smaller angle
•
16.3
17.1
Of lodes yielding both tin and
and copper
Of copper lodes
•
Of all the lodes the proportion heaved towards the smaller angle is
Of the tin lodes
Of lodes yielding both tin and copper
Of copper lodes
The mean distance of the heaves of all the lodes is
""
""
"
""
""
This table is given for the purpose of showing the observed results of the
dislocations. It has long been a habit amongst miners to speak of heaves, as
if the lode had been an active agent in producing the phenomena. It must
not, however, be forgotten that the lode heaved has no influence upon the heave
itself. A mineral vein is formed in a fissure, which has been produced by
some movement of the Earth's crust, the crack running, it may be, east and
west. By the operation of another disturbance running at nearly right
angles to, or at some angle with, the first disturbance, the lode is broken, and
consequently, that portion of the lode between the fractured ends is moved
or heaved.
Having endeavoured to give what appears to be the most simple explana-
tions of the phenomena, which are often seriously perplexing to the miner-
so much so that heaves are in many districts commonly known as troubles—it
is only justice to Mr. Henwood, who has recorded more observations of these
phenomena than any other man, to quote his views, which are given in a
* "It is remarkable that all the principal heaves in the district from Chacewater to Camborne should
be to the right, while those to the left are but insignificant in comparison with them."—Mr. Thomas's
Report.
670
[BOOK III.
PRACTICAL MINING.
section of his work, named by him "Relations between the Rocks and the
Intersections of the Veins which traverse them
"From the difficulty of the inquiry, and its uncertainty, I cannot state
whether the difference between these numbers (those given in the table, p. 669)
depends merely on the much greater area occupied by the Slate than by the
Granite in the tracts here considered, or whether the intersections of veins are
really more common in one rock than in the other, under conditions otherwise
similar.
"If we regard the total number in each rock as 100, then the respective
proportions will be as follows, viz. :-
The intersections without heaves
Heaves towards the right hand
,,
""
left hand
greater angle
smaller angle
The mean distance of all the heaves is
""
""
In Granite.
26.2 per cent.
•
52.4
•
21'4
65.6
8.2
in Granite
in Slate*
•
•
In Slate.
21.5 per cent.
50.5
26.0
""
"?
64.0
""
14.5
16.4 feet.
17.I
16.3
"The relative proportions seem scarcely sufficient to warrant the idea
that the slight differences between them have much connection with the
containing rock.
"It has been seen that the 233 intersections are effected by 125 veins of
clay, or flucans; and 108 quartzose ones, or cross courses. The proportions on
which they occur in the different rocks are-
Flucan
In Granite.
78.7 per cent.
21.3 ""
•
Cross Courses.
In Slate.
47'0 per cent.
53.0 ""
"This result is in accordance with the general fact long recognised in
some parts of Cornwall, that the cross veins far more frequently partake of the
nature of the contiguous rock (and are thus characterised as flucans) in the
Granitic than in the Slaty rocks, and that in the latter they are much more
generally quartzose in their composition, and are thus designated cross
courses.
"The intersections of cross veins by lodes are 23 in number; of these 36
per cent. are in Granite and 64 per cent. in Slate.
"Twenty instances of lodes intersected by other lodes have been recorded,
of which 20 per cent. are in Granite and 80 per cent. in Slate.”
After giving several tables which appear to confirm his views, Mr. Hen-
wood proceeds :—
“This inquiry has established the fact that the extent of the heaves is in
direct proportion to the width of the lodes, as well as to that of the cross veins,
whilst here it would, at first sight, appear that this part of our inquiry
shows the extent of the heaves to be in direct proportion to the width of the
cross veins, and in an inverse one to that of the lodes. It must not be for-
gotten, that a preceding investigation has conclusively proved, that the extent
of the heaves are in direct proportion to the width of the lodes, as well as of
the cross veins, and this would lead us to expect that the diminution of
energy in the one class of veins would be compensated by the increase of it
in the other; and therefore that as their opposing influences so exactly
* The average distance of the two heaves in the elvan at Ting-Tang is 14·5 feet.
CHAP. III.]
ZIMMERMANN'S RULE FOR FAULTS.
671
counteract the other, any apparent difference in the result at different levels
should be owing to the influence of depth alone."
Several isolated statements must now be selected from Mr. Henwood's
copious observations :—
"The general rule undoubtedly is, that the heave of the same lode, by the
same cross vein, is in the same direction (towards the same hand) at all depths;
but, in a few instances, lodes heaved towards the right hand at one level are
heaved towards the left at another." Mr. Carne states that at Gunnis Lake,
at the depth of 70 fathoms, the lode is heaved 15 feet to the left, and at 10
fathoms deeper, it is heaved 15 feet to the right. (Is not this a movement of
one section of the rock, while the other remains at rest?)
"In order, however, that a heave should take place, it does not seem
absolutely necessary that the lode should be traversed either by another lode,
a cross vein, or even by a joint of the rock; for at Balnoon the lodes are
frequently cut off, and heaved by the joints of the rock, and often, too, when
these are wanting (?). Of the latter kind there is also an instance at Dowgas,
where four lodes abruptly terminate alike without the intervention of either
joins or vein, and are again found to commence with similar abruptness,
nearly at right angles, and at a distance of about 4 fathoms."
"The intersections of lodes by flucans show a numerical preponderance
of heaves towards the greater angle, and also that the extent of the heaves is
greater with tin than with copper veins, which also holds true in the leaps
occurring with vertical intersections; whilst the displacement (whether a
heave caused by a flucan or a leap occasioned by a stick) of copper lodes is
more frequently towards the greater angle than is the case with lodes yielding
other ores."
"Again, the heaves of lodes by each other and by cross courses exhibit a
larger proportion of heaves towards the smaller angle than results from their
heaves by flucans. The law most remarkably prevails in their vertical
intersections also; for the leaps towards the smaller angle are in much
larger proportion than those towards the greater angle; an excess which
also holds good when the leaps caused by the intersections of lodes by each
other are compared with those of lodes traversed by slides. The displace-
ment, whether it be a heave or a leap, is far more commonly to the smaller
angle when the traversing vein has a quartzose than when it has a clayey
character. These circumstances rather indicate that the direction of the
heave or leap may be affected by the mineral composition of the intersect, as
we have already seen it is by the intersecting vein."
Especial attention should be directed to these quotations, which assume
that the vein has a power which cannot be ascribed to it.
Professor Hanns Hoefer, of the Mining School of Leoben, has recently
given the following methods for determining faults in mineral veins.*
The rule of Zimmermann has been usually followed. This assumes that the
hanging wall of a faulting-fissure has slid downwards in the direction of its
dip. But dislocations show many cases in which one part of the seam
* "Zeitschrift für Berg-und Hüttenwenen," vol. xxix. A careful abstract of this paper, by Dr. R.
W. Raymond, was printed in the "Engineering and Mining Journal" of New York, of which he is one of
the editors.
672
[BOOK III.
PRACTICAL MINING.
has been shoved over the other. The hanging-wall of the faulting-fissure has
slid upwards instead of downward.
Every dislocation of mineral deposit by a cross fissure was long regarded
as belonging to one or the other of these two classes; it was either a slide or
a heave.
It is assumed that throughout a given fault the motion of the hanging-
wall has been everywhere the same, and consequently that the so-called
throw, determined by exploration of the two dislocated parts of the deposit,
is a guide for exploration at all other points.
For the following illustrations we are indebted to a carefully-prepared
abstract of Hoefer's memoir by Dr. R. W. Raymond, of New York.*
"This phenomenon itself suffices to show that the classification of dislo-
cations is not so simple as has been supposed, and the methods pursued by
mine surveyors, based upon that classification, may, therefore, need improve-
ment. These methods, as is well known, assume that throughout a given
fault the motion of the hanging-wall has been everywhere the same, and
consequently that the so-called vertical interval or throw determined by
exploration of the two dislocated parts of the deposits at any one point is a
guide for exploration at all other points. Practice, however, shows that this
guide is not unerring. It does not always agree with the indications of
ĺ
A
E
C
H
Fig. 188.
G
actual movement and direc-
tion furnished by the stria-
tions of the walls of the fault-
ing - fissure. These marks
frequently do not follow the
dip, but obliquely across it.
The oblique or other motion
thus indicated is certainly
one of the elements in the
geometrical problem pre-
sented to the surveyor.
"Fig. 188 may illustrate
this point. Let A B be the
line of intersection between
the vein L and the faulting-
fissure V, the striations of
which indicate that the
movement took place in the direction of C D. The dislocated continua-
tion L' of the vein being found at E F, the old rule would declare that the
case was one of a heave, or upward movement, of the hanging-wall; and yet
it is really an oblique slide. That the distinction is important appears when
we consider that, if the vein being worked in the foot-wall of the faulting-
fissure had contained an ore-body which was cut off by the fault at G, the old
rule would require us to accept the continuation of this ore-body at some
higher point in the hanging-wall of the fault; whereas, by the present
hypothesis, it is at the lower point H to which the striations tend. It is
* "Transactions of the American Institute of Mining Engineers, 1882," being a paper read at the
Washington meeting of that Society.
CHAP. III.] HOEFER'S MODE FOR DETERMINING FAULTS. 673
apparent that an oblique slide would not, according to the old rule, appear
to be a slide at all, unless the striations (that is, the indication of actual
movements) were steeper in dip than the lines of intersection. In case L' had
been horizontally moved, the dislocation would, by the old rule, be a slide if
it had moved in one direction, and a heave if it had moved in the other;
whereas in reality it would have been neither."
But Professor Hoefer goes farther, and declares that the parallel uniform
movement of the hanging-wall of a fault is not to be always assumed. The
evidence of this statement is drawn especially from coal seams; not because
the dislocations of these deposits are different in nature from those of metal-
liferous veins, but because coal-mining has furnished more extensive exca-
vations, and therefore a greater body of evidence than any other branch of
the business. Moreover, we can with greater certainty judge what was the
original position of a coal-bed, than we can of a fissure-vein. When the
latter suddenly changes dip, for instance, beyond a fault, we cannot be sure
that the change of dip did not exist before the dislocation took place. This
phenomenon of a change of dip and also of strike is frequent in coal-fields,
under such conditions as make it reasonably certain that neither the original
position of the coal nor irregularities in the faulting-fissure were the cause;
but rather that the relative movement of the two parts of the deposit was not
in parallel lines.
In many cases where veins show a uniform dip, that is, approach in
form a regular plane, and yet exhibit these changes beyond a fault, it is
reasonable to infer, instead of a simple slide or heave, a partial revolution of
the mass on the hanging-wall side of the fault around an axis normal to the
plane of the faulting-fissure. Professor Hoefer refers to a very extensive
fault in the neighbourhood of Aix, which shows to the south-east a greater
vertical dislocation than toward the north-west, which he thinks can only be
explained by a turning movement. The centres of movement would be found
at the intersection of perpendiculars drawn through the line of striations
produced by the revolution.
"Thus, if striations were exposed, the intersection of the perpendiculars
would show the centre of movement. In practice, however, it is likely that
the several perpendiculars drawn through such striations would not intersect
at a given point; and this would show that, besides the turning movement,
there had also been a movement of translation of the whole mass, up, down,
or along the plane of the fault. The complication of these two movements
is, however, not beyond analysis, if the data are sufficiently abundant and
exact. Even with the imperfect data usually afforded by the limited expo-
sures in mines, it is much better to work upon a perfect than upon a crude
and partial system; and Professor Hoefer thinks that not only the points
already mentioned, but also the question of direction of movement, can in
many cases be satisfactorily determined by the plan he proposes.
"This plan may be illustrated for a general case by Fig. 189. Let A B
represent the course of a vein dipping 32° (as shown by the arrow), which has
been explored on an upper level to where it is cut off by a cross-fissure
having the strike B K and the dip of 40° (as shown by the arrow). Let it be
assumed that upon a lower level the vein had been opened, with the strike
674
[BOOK III.
PRACTICAL MINING.
CD and the dip of 23°; that on this level a fault was encountered at D, having
the same strike and dip as that at B. By a simple construction, with the
help of the triangle a b c, in which the angle c is 40°, and the side a b is the
vertical distance h between the two levels, we find the point c and draw the
T
M
23↑
123
i
U
Ꮐ
F
132
N
W
line cD, which, being parallel to BK,
and also coinciding with the strike of
the fault at D, proves the latter to be
identical with the fault at B on the
level above. We now determine the
two lines of intersection EF and B G
made by the fault, with the two por-
tions A B and CD of the faulted vein.
This can be done most easily by the
aid of the two triangles, def, ghi, in
which the base h is taken equal to
the vertical distance between the two
levels, and the angle opposite h is, in
each case, the angle of the dip. A B
and CD being already given, the cor-
responding lines, namely, HJ on the
level of CD, and K L on the level of
A B, are to be found. This is done by
drawing HJ parallel to AB through
the point ƒ, and prolonging hg parallel
to CD. The course of the fault at B is
known; hence the line B K drawn on
that course intersecting the line K L at
K determines the point K for that
level, while for the next lower level
the point H is determined by pro-
ducing the line C D parallel with B K;
in like manner, the lower levels, TU, V W, MON, PQ, RS, &c., can be
plotted. It is evident that, by drawing lines through K D and B H, the lines
of intersection E F and B G are obtained. It is evident also that on the fourth
level M, if in working from M the fault is encountered at O, it will not be neces-
sary to cross-cut, as in the upper levels, to find the continuation of the vein;
since at that point, which is the centre of revolution, the vein can be found
by simply breaking through the cross-fissure. In the next lower level, P Q,
however, if the fault is encountered at Q, it will be necessary to cross-cut for
the continuation of the vein in the direction QR, a direction opposite to that
which would be necessary at U or D."
Fig. 189.
a
B
6
It will be seen that in this case a revolution has been demonstrated with-
out the help of the indications afforded by the striations.
Professor Hoefer indicates also how this graphic method may be applied
to lines of intersection, which are not straight, but curved; and to the still
more complicated case of a varying strike at different levels in the faulting-
fissure itself; that is, for instance, when B K, HD, V U, and Q R are not
parallel.
CHAP. III.]
MOVEMENTS PRODUCING FAULTS.
675
He recommends in practice the adoption of the method above de-
scribed, on the ground that it involves no generic assumption or hypothesis,
but makes the work of the surveyor in the first place purely descriptive, and
also checks by graphic construction the errors of observations due to irregu-
larities in the vein and fault. He points out also that this method indicates
conclusions as to the nature of the movement which has taken place; since,
if the two lines of intersection are parallel, the movement must have been
parallel; while if they converge, the movement must have involved a revo-
lution, and the points where they intersect must be the intersection of the
axis of revolution with the plane of the fault.
Dr. Rossiter W. Raymond, in bringing a notice of Professor Hoefer's
graphic method before the American Institute of Mining Engineers, observes
that it will not indicate, in a case of compound movement involving both a
revolution and a slide (Fig. 189), either the existence, the direction, or the
amount of the displacement. Therefore, he argues that cases must often
arise in which the method would fail in the direction of guiding the miner in
search of the lode which has been lost through the influence of the faulty
fissure.
In continuation of his argument, Professor Hoefer says :-
"The solution of the problem remains in principle the same when the
lines of intersection are curves. If, for instance, we had plotted a fault for
different levels (not too far apart vertically), and had found the facts on
actual exploration to differ from our construction, that is, the lines of inter-
section, imagined as drawn in the plane of the fault, had proved in practice
to be longer or shorter than required by our construction, we should then
obtain a number of elements of the actual curved lines of intersection, which
we could prolong according to
their curvature, in order to
operate further with them, just
as if they were straight.
IN
I
11
GD
RAM
C
B
HF
I
N
11
“To take an example: sup-
pose (Fig. 190) that the fault
had been encountered on level
I, in the two portions of the
vein, at A and B, giving at
these points the straight lines
of intersection A D and B F; but
that on level II the fault was
found at G, not D, and the con-
tinuation at H, not F. Straight
lines drawn from A through G,
and from B through H, thus
become the lines of intersection for the construction of the fault on level I I.
But actual developments show the points sought to be J, K, instead of L, M;
and, in short, we become able to prolong the curves A G J, B H K, as curves,
and thus to obtain for lower levels, in advance of exploration, more accurate
determinations."
I
E
Fig. 190.
Dr. R. W. Raymond's remarks on this method of plotting and deter-
X X
676
[BOOK III.
PRACTICAL MINING.
mining faults in mineral deposits are of considerable value; his ex-
perience and strictly scientific training rendering him one of the most
accurate observers of the phenomena of mineral veins to be found in the
United States of America, and thoroughly qualified to discuss with Professor
Hanns Hoefer of Leoben the geometrical method proposed by him. Dr.
Raymond gives his opinion that the classification of dislocations is not
so simple as has been supposed, and that the methods pursued by mine
surveyors need improvement. This bears very strongly on the condition of
many of the mine surveyors in this country, and their attention is therefore
especially directed to the following remarks made by him at the Virginia
meeting of the American Institute of Mining Engineers :
"The relative position of the two parts of the faulted vein, shown in
Fig. 190, may have been reached by a simple revolution around an axis
normal to the fault at O, or by a revolution around some other axis normal
to the fault, coupled with a slide along the fault. For instance, the axis of
the revolution may have been at U, and the slide may have carried it
apparently to o.
"Yet this is precisely the case which may be expected to be most
frequently encountered in practice. Simple revolutions must be rare, if,
indeed, they ever occur. My own impression on this point is confirmed by
the reply of Professor Hoefer to an inquiry which I addressed to him after
perusing his paper. He says:—
"Circular movements, combined with movements in straight lines, are
very frequent in our faults; in fact, I do not doubt at all, that a continued
careful study will show them to be the rule. Whether simple revolutions
often occur is very difficult to decide, from the observations thus far avail-
able. You know how one-sided and incomplete the inquiry has heretofore
been in this direction. In the southernmost district of Przibram, the
Clementi vein shows in its selvage striations, the varying directions of
which indicate a circular movement; and my studies (unfortunately inter-
rupted by my departure) led me in this case to the belief that the movement
had been circular only. But I did not consider the question definitely
settled.'
"In this case, the study of the striations in the faulting-fissure may give
valuable, though perhaps rarely exact, indications as to the direction of
movement. If the rectilinear movement followed the circular one, the stria-
tions may furnish a clear record of it in straight lines. If the two were (as
is more probable) simultaneous, the striations would be strictly epicycloid
curves; but for their interpretation it would be sufficiently accurate to
consider them as fragments of ellipses, having their major axes inclined in
the direction of the rectilinear movement. These indications would doubt-
less be, in most instances of practice, merely general guides to exploration.
But after, by such exploration, the continuation of a given ore-body (as D,
Fig. 189) had been found, it is plain that the whole movement of the faulted
vein could be analyzed and plotted, and that the continuation of any other
ore-body could be sought with confidence. In the case before us, it would
be only requisite to determine the relations of the point actually found to
D', its theoretical position on the hypothesis of purely circular motion; and
Maou
CHAP. III.]
SCHMIDT ON DISLOCATED LODES.
677
the correction thus applied to D¹ could be applied to any other point similarly
determined.
"I should remark, in conclusion, that all these constructions rest upon
the assumption that the dip of each segment of the faulted vein is constant.
That is, the vein is treated as a plane. But it would not be difficult to
include, in the method here shown, changes of dip and strike, as these might
be discovered in actual working; and under certain circumstances, a change
of dip might serve as a useful landmark in surveying. For instance, if, in
Fig. 189, there were a change of dip in the left-hand portion of the vein, at
the level CD, then the corresponding change of dip must be shown on the line
G B, at the point formerly adjacent to D; and the discovery of this point
would at once, as has been already shown, permit the analysis of the
movement which had taken place, and the deduction of all its resultant
relations."
Schmidt, a Bergmeister at Siegen, about 50 miles north-east of Cologne,
was the first to recognise the exact effect of one lode crossing and dislocating
the other, and he found that the younger lode always carries the older lode down-
wards with it, according to the dip of the dislocating lode. He therefore proposed
the following rule of throw :—
First. Vertical Dislocation.—If the dislocating lode dips towards you, you
must follow it upwards in order to find the continuation of the older lode ; if
the dislocating lode falls from you, you must follow it downwards to get at
the older lode.
Second. Horizontal Dislocation.-You must follow the dislocation on the
side of the obtuse angle which it forms with the thrown lode.
In some districts faults are observed to have occurred so, that several
portions of the country have been dropped down in one direction, prolonging
the surface appearance of some rocks beyond that which would otherwise
have happened after the various denudations to which they might have been
exposed. The amount of accumulation thus preserved, or the reverse, by
systems of faults, is a subject which should engage the attention of miners
and geologists as one of importance. As might be expected, lines of faults
frequently exhibit minor complications, and even disturbances, showing a
certain amount of lateral pressure, during the adjustment of their sides after
the action of the force producing the original fracture.
De la Beche's "Observer" will be found to contain many valuable
observations on the occasion of faults. Whether faults arise from minor
adjustments of the Earth's crust, the bending, contortion, and squeezing of
various accumulations being regarded as more considerable consequences
of these adjustments, or from other causes, together with the greater plica-
tions and flexures, they show a broken and dislocated condition of that
crust which it requires the miner and geologist to bear in mind when
endeavouring to trace the facts he may observe in connection with ore
deposits and the movement of veins to their sources.
Attention is directed to Fig. 37, p. 294, showing a very elaborate set
of faults occurring in the bottom of Penhalls mine, in St. Agnes. Here there
are a succession of movements, up and down, all of them well marked by
* Consult "The Geological Observer," by Sir Henry T. de la Beche, C.B., F.R.S., 1853.
X X 2
678
[BOOK III.
PRACTICAL MINING.
their influence on the lodes and "gossans" of that district. Captain Bennetts,
the chief agent of Penhalls mine, has been enabled to determine that several
considerable thicknesses of strata have been removed by denudation from
the surface of the country.
A vertical section may only give the apparent movement of the parts of
rocks fractured and faulted. It is, therefore, desirable that the miners should
search for the direction of the friction marks, the line attending the pressure
of the rocks on one side, against those on the other, in order to discover that
in which the movement has really been effected. This investigation will
sometimes lead him (Sir H. de la Beche remarks) to find that, though the
general plane of a fault may dip in a given direction, the movement has not
always corresponded with it. This is a most important matter for the
miner to make out. Some of these friction marks bear evidence of the
action of enormous pressure, more especially in those cases where the dislo-
cations may, in its plane, be very considerable, and yet the rocks thus
moved against each other, and once so far asunder, may be now closely joined
together. The contents of dislocations, that is, of the fissure produced by
the fracture, whether known as common faults or mineral veins, often
present beautiful impressions of those friction marks;-parts of the walls
of the fracture often grinding against each other in their movements, having
finally left cavities in which various mineral substances were accumulated,
taking the form of the surfaces against which their first deposit was
effected.
COMMERCIAL NOTES.
Valuation of "Tin Stuff" (Tin Ore).—It has been customary to buy and
sell tin ore by measure-the measure being arbitrary. Tin for a long period
has been measured by the sack. This is due to the old practice of carrying
the sacks of tin, from the mines to the smelting-house, on the backs of
mules.
In some districts the sack contains 8 gallons; in others the sack varies
9 to 12, and even 18 gallons, of 282 cubic inches, or beer measure. There are
some difficulties in ascertaining the value of the tin ore by measure.
"The
sample" taken for assay is by wine measure, the produce is weighed by troy
weight, and the total quantity of tin is estimated by avoirdupois weight.
Dr. Rickard, in his "Miners' Manual," says: "The following rule was very
much employed some years since, and it will be seen that the buyer preserved
a large margin for loss in dressing, as well as for profit.
"Every penny-
weight of black tin produced from a sample of one gill wine measure, will
give 160 lbs. avoirdupois in 100 sacks of 18 gallons each beer measure; but
the following example will show that for every pennyweight so obtained
2401932 lbs. avoirdupois would be nearer the truth. Example: Find the
quantity of black tin in 100 sacks of 18 gallons of tin-stuff, when a gill
produces i dwt. In one gallon there are 32 gills, this gives 32 dwts. per
gallon; then 32 × 18 = 576 dwts. in every sack of 18 gallons wine measure.
But I gallon beer measure will contain 1.22 gallon wine measure; therefore,
576×1*22=702°76 dwts. in one sack beer measure. And multiplying this by
100 we obtain 70.272 dwts. as the quantity of black tin in 100 sacks. But
•
CHAP. III.]
SAMPLING AND SALE OF ORES.
679
24 grs. make 1 dwt., and 7,000 grs. make 1 lb. avoirdupois, as the real
quantity of black tin contained in 100 sacks. Thus-
70272 X 24 1686528
7000
=
7000
240°932 as above.
The difference between 240°932 lbs. and 160 lbs. on every 100 sacks
being 80.932 lbs., or rather more than one-third of the whole, was thus lost
to the seller.
This is an example of the loose way in which the tin-miner's business
has been transacted. The late Captain Charles Thomas, of Dolcoath,
remarks, in his "Tin Tables": "This does not give the correct quantity of
tin contained in 100 sacks, it only pretends to give such quantity as purchasers
are inclined to purchase at, after allowing for profit," &c.
The only correct mode is to weigh the tin-stuff, as copper ores are
weighed, deducting for loss by water, and taking any sufficient quantity of the
ores by weight as the sample; weigh the produce by equal parts of the same
weight. These equal parts may be twentieths, giving the produce at so
much for twenty, as is the present practice among tin-smelters. At Dolcoath
the assayer employs the usual copper assay weights, taking for the sample
double the weight marked 100, and weighing the produce by the one-
hundredth part; this of course gives double the produce.*
Sampling and Sale of Copper Ores.—In copper mines several “pairs” or
companies of miners are generally employed in raising the ores. The
produce of their labours, being nearly of the same quality, are generally
mixed together in one heap called "the parcel," a sample being first taken
from each company's pile, to ascertain the exact produce of it.
From the ores thus mixed, a sample is taken by the agents of the copper
companies, and the whole "parcel" is sold according to the result of that
sample. Copper ores are sold in Cornwall, and at Swansea, by public sale,
which is known as the "Copper Ticketings." All ores are sampled by the
companies' agents, or "samplers," a fortnight before the ticketing at which
they are sold; thus three weeks' notice are usually given of that intention,
by naming the day of sampling.
Copper is sold by the ton of 21 cwts. dry weight, the allowance for water
being made according to the loss obtained by evaporating 1 lb. avoirdupois
of the ore to dryness.
At each ticketing the chair is taken by the manager or purser of the
mine which sells the largest quantity of ore.
The sale is by ticket. The agent of each copper-smelter present writes
the prices per ton which he offers for each parcel in one mine on a slip of
paper (a ticket), which is carefully folded and passed to the chairman.
When all the tickets are collected the chairman opens them, and reads the
offers of each company aloud, in the order in which they stand arranged in
the ticketing paper, each offer being repeated by the vice-chairman. At
these meetings blank forms are provided, on which each offer is entered
under the name of the company making it. If two or more companies make
the same offer the parcel is equally divided between them.
* Consult the "Miners' Manual of Arithmetic and Surveying," &c. &c., by William Rickard, in
which will be found several problems carefully worked out.
680
[BOOK III.
PRACTICAL MINING.
Copper Ore Standard. This term, the "standard," is called by Mr.
Keates, the copper-smelter, "the everlasting stumbling-block of copper trade
technicality." This gentleman communicated to Dr. Percy the following
information on this subject*:-
"Originally there were few copper-smelters and few miners, and it was
customary for the former to contract with the latter to buy their ores for
periods varying from a quarter to one year, agreeing to pay them for the
same according to a standard price of copper determined on, and which price
was usually the selling price of tough-cake copper at the time. Thus, if
copper were selling at £120 per ton, the standard was fixed at that rate or
thereabouts. Out of this standard price the miner returned to the smelter a
certain sum on every ton of ore sold (the ton of copper ore is always 2,352 lbs.
or 21 cwts.), which for many years was 55s. per ton, though originally
it was more. This was called the returning charge. The miner also
gave the smelter i cwt. upon every ton to cover waste on removing the ore
from the mine to the smelting works. The smelter was also allowed a
varying number of pounds of ore in each ton as compensation for moisture
in the ore, the bulk being weighed wet, while the assayer's sample was
weighed dry."
"C
Example.-Suppose a bargain made, and the ore weighed by the miner
to consist of two parcels, one of 1,004 cwts., which is guessed to contain cwt.
of moisture per ton; the other of 800 cwts., which is guessed to contain cwt.
of 'moisture per ton, so that in the first case the quantity of ore paid for is
only 40 tons 14 cwts. I qr., and in the second case it is only 36 tons 15 cwts.
2 qrs. Let the first parcel produce by assay 10 per cent., and the second
54 per cent. of copper. In the first parcel the gross value of the copper in
the ton of ore will be £12 12S., the standard price of copper being £120.
For 100 parts of copper (say 1 ton) £120::10 parts: £12 12s. But from this
gross value of the copper in the ton of ore the returning charge must be
deducted. Thus, the gross value of the copper 12 12s., returning
charge £2 155., price per ton of ore £9 17s. In like manner the price of
the second parcel of ore will be found to be £3 11S. Thus far the term
standard is simple and intelligible, meaning neither more nor less than the
price of copper."
The smelter has no longer got his standard price of copper arranged
with the miner as of old, but he opens his eyes to all the circumstances, or
ought to do so. He sees what sort of ore he wants; he knows the rate of
carriage and freight which he will have to incur on each parcel; he knows
that one lot melts easily, another with difficulty, a third makes good copper,
a fourth bad, and so on; and in the end he finds he has bought the five lots
of ore above mentioned at the prices affixed. Immediately these prices are
disclosed in the sale-room, the miners' and smelters' clerks proceed to calcu-
late the standard in the following manner :
Prices of the ore of 5 per cent. produce .
Add returning charge
*
£
s. d.
4 12
2 15 O
770
Metallurgy," vol. i. p. 304. By John Percy, M.D.,
F.R.S.
THE "STANDARD" FOR COPPER.
681
CHAP. III.]
But this sum refers to the ton of ore, or 5 per cent. of the ton of copper, so
that the standard of the ton of copper will be £7 7s. × 20=£147•
Again :-
Prices of the ore of 20 per cent. produce .
Add returning charge
£ S, d.
21 15 O
2 15 0
This multiplied by five gives the standard of £122 10s. Hence the standard
is now deduced from the price, and not the price from the standard, as formerly.
The buyer makes his offer without thinking of the standard. When the sale
is over, the average produce of all the parcels of ore is determined, and also
the average standard. Taking the five lots enumerated, the average produce
is 12 nearly, and the average standard £132 4s. nearly. The only purpose
which this modern standard serves is a ready mode of comparison of prices
or of rates at which copper in the ore has been sold. For instance, instead
of saying last week ores of 5 per cent. produce sold for such a sum, and
this week they sold for such a sum, the phrase is, the standard is down a
couple of pounds, or up £5, as the case may be.
3
The sources of the smelter's profit were-the care with which he got his
ores transported from the mine to his works, so as to save as much as
possible of the I cwt. of ore in each ton, which he did not pay for; the portion
of the £2 15s. returning charge which was not actually expended in smelt-
ing; and the surplus or quantity of copper which his furnaces yielded in
excess over the crucible of the assayer, and this of course would vary with
the skill, as well of the assayer as of the smelter. Originally copper ores
were dressed to a pretty uniform rate of produce, perhaps from 9 to 12
per cent. But the smelter, more acute than his neighbours, saw that he had
better buy those of 5 per cent. and leave the others, because it took a less
portion of the £2 15s. to smelt a ton of ore of 5 per cent. than in tons of
ore of 15 per cent. produce. Now the simple mode of meeting this was to
have had a varying scale of returning charges, instead of which these
charges remained the same, while the standard was varied with the varying
produce of the ores, so that with copper at £120 there might be a standard
of £115 or £130, and thus the word "standard" lost its former simple and
correct meaning. Competition went on increasing, processes were improved,
carriage, freights, coals, &c., were lowered, but the returning charge con-
tinued the same, with of course less applicability than ever to the varying
produce of the ores.
An illustration of what actually occurs at a modern sale will make the
matter plain. Out of a modern sale of 3,000 or 4,000 tons of ore, varying in
produce from 4 to 20 per cent., let us select the following lots with the prices.
at which they were sold :-
100 tons of 5 per cent. produce
£ S.
4 12
a.
O
8 I O
""
8
12
""
""
""
""
""
16
20
""
•
12 18
•
17 8
21 15
O
M. Moissenet, of the École des Mines, Paris, being in a difficulty, which
will be readily understood, requested the author, as his friend, to ask some
questions of Dr. Rickard, the author of "The Miners' Manual."
The
682
[BOOK III.
PRACTICAL MINING.
following letters were the result. These so fully explain the difficulties that
it will be right to print them in this place from the original MSS.:-
"I have taken the returning charges on copper ore at £2 15s. per ton in
calculating for the price, which is quite correct; but in giving the rule for
obtaing one standard from another I did not confine myself to any fixed
returning charges, but gave it generally. In the examples, however, I have
used the number £135, because the results agreed with those given in tables
already published by Messrs. Jehu Hichens, Davey and others, which were
considered near the truth. I have not, however, confined myself to that
number, as you will perceive. In a communication to the Mining Journal
last summer, I expressed an opinion that the average standard of the weekly
sales is of no use to the miner, and that its only use is to compare the state
of the market, in which case the £275 should be invariably employed. I
will now go a step further, and state that in those mines where the average
standard is made the basis of the division of money among the men, it is
very frequently improperly divided, some getting too much and others too
little for their ore.
"I am not a smelter, and consequently not an authority, but I think the
following comparisons will prove that at least I have reason on my side.
"In order to find the standard at the ticketing, £2 15s. for every ton of
ore are added to the amount of sale, and the result divided by the quantity
of fine copper, irrespective of quantity sold; also the price of a ton of ore is
found by multipyling the standard by the produce, and dividing by 100,
deducting £2 15s. from the quotient; consequently the standard may be found
from the price when the produce also is known. Applying this, then, to the
sale of October 7th, 1858, of which I happen to have a few produces, I find
the following, viz. :—
Produces of three parcels of
"Standard of sale, £123 19s. Produce, 7.
West Seton ores, three parcels of Clifford, and three parcels of South Wheal
Francis, with prices, &c.
West Seton mines
Clifford Amalgamated
•
South Wheal Francis
Tons.
I. 78 at
2. 56
3. 43",
I. 120
""
Pro- Calculated
duce. Standard.*
£ s. d.
151 2 2
33
O 132
98
Calculated Orc.
Copper.
£ s.
69 12
a.
7
Price.
£ s. d.
""
2 7 O
12 18
596
5 0
113 16 4
126 10
9
93 16 4
84 4
6 6
о
5
164
129 II
136 0 O
109 7 7 8
83 15 0
81 O
92 9 2
123 19 O
85 7 O
126 10 9
84 4 7
113 16 7
90 8 6
I
4
2. 49 "
3. 20 15 O 6
I.
""
77", 6 I O
2. 57,
5 9 6
3. 55 10 12 6
""
-l2SH
7
II
3
"You will perceive from the above that the price for ore copper varies for
every produce, and that it follows no fixed rule-produce 112 bringing
£90 8s. 6d.; 13, £93 16s. 4d.; while 161 brings only £92 9s. 2d.
<<
According to Davey's tables, the standard for 13 will be £114 16s. 5d.,
while by adopting £175, as in the Mining Journal reports, it would be
only £112 2s. 5d.; but taking £275 the standard will be found £105 7s. id.,
the difference between which and the true standard as above, £113 16s. 4d.,
is £8 9s. 3d., and this is the difference between the prices given for the ore
copper, and therefore the standard at par would be £105 7s. Id. The
* Calculated from the produce and price.
CHAP. III.]
AMOUNT OF RETURNING CHARGES.
683
standard obtained by using £175 is near the true standard; it does not,
however, give either the true standard or the standard at par, nor is the
difference constant. The following table shows the error:-
Difference of
Standard.
£ s. d.
Difference
of Price.
s. d.
4 10 too low.
Produce.
True
Standard.
£ s. d.
Standard calcu-
lated from £175.
£ s. d.
151 2 2
151 4 4
0 2 2
I
132
113 16 4
112 2 5
I 13 II
126 10
9
126 6 4
0 4 4 5
0 4
129 II
8
128 II
2
I O 6
I 3
""
136 O O
134 7 10
I 12
2
I 6
I
161
109 7 8
II
113 16 7
110 3 8
114 5 8
O 16
08 I
O
2 5 too high.
I O
"
""
"Davey's tables give still greater variation. Hence I conclude that in
comparing two standards according to the present mode of calculating the
standard, the number £275 or £2 15s. per ton should be used; but that for
the purposes of the miner the standard should in all cases be calculated
from the produce and price, unless the smelter purchase at a price per unit
of produce; at all events the miner should in every instance know the
produce of his ore.
"Since I wrote on Thursday last I have looked carefully into M.
Moissenet's questions, and find that by the rules given in the 'Miners'
Manual' two at least of the three may be answered. The amount of
returning charges employed in my examples, namely £135 per 100 tons,
will not, however, give the exact rise or fall quoted in the journal; but on
applying my rule to £175 per 100 tons, or £1 15s. per ton of ore, I obtain
correct results; that is, my results agree with those in the Mining Journal,
errors excepted.' And I find this a necessary condition; for instance, in the
Journal for December 10, I find the rise in the standard on the correspond-
ing sale for the previous month quoted at £3 1s. 6d., but it ought to be
£3 7s. 6d. I will endeavour to answer M. Moissenet's questions.
"Question 1.-To find the rise or fall in the standard. The rule for this
will be found at page 29 of the manual.
"Example.-The average standard of the sale, December 8, 1859, was
£139 6s., the average produce being 6. On the 12th January the average
standard was £145 10s., and produce 62. Required the rise or fall on the
standard.
"Taking the returning charges at £175 per 100 tons of ore, the calculations
will be as follows:-
Standard for 8th Dec.
Subtract quotient of
175
6 / 15
Add quotient of 175
Standard at par.
Average standard Jan. 12th
Rise on standard
£
S.
d.
0
139 6
26 18 5
II2
7 7
25 18 6
138 6 O
145 10 O
7 4 0
"Again, the average price on the 8th December is quoted at £6 6s. 6d.,
while on the 12th January it is £7 3s. It will be seen that the standard at
684
[BOOK III.
PRACTICAL MINING.
par for 6 is £138 6s. Calculating the price, then, for produce 6 at this
standard, we obtain as follows:-
£ s. d.
138 6 0
61
829 16 O
69 3 O
34 11 6
9,43 10 6
20
6,70
12
8,46
£
S.
968
2 15 0
6 11 8 price per ton at par.
"Then £7 3s., less £6 11s. 8d., will leave 11s. 4d. rise; but the rise quoted
in the journal is 9s. 9d., which may be thus explained: the average produce
is quoted at 6, being nearly th less than the truth; this at standard
£145 10s. will give price £7 1s. 3d., only from which subtracting £6 11s. 8d.,
the difference 9s. 9d. agrees exactly with that given in the journal. The
amount of sale divided by the number of tons of ore gives £7 3s. as the more
correct average price of the sale.
"Question 2.-Given the standard £144 10s., and produce 6, to find what
standard should be given for the same kind of ore producing 49.
"The rule for this will be found on page 28 of the manual, and taking the
returning charges at £175 as before, we have—
Given standard
175
Subtract
6
Add '755
81
Standard at par for produce 48
•
"Should the standard be required for 83, then-
To the above difference
175
Add
8 /1/585
Standard at par for produce 8
•
£ S. d.
144 10
O
26 18 5
117 II
37 16 9
155 8 4
£ S. d.
•
117 117
20 II 9
•
138 3 4
(6
Question 3.-I believe this question can only be answered generally. In
the first place, the price for the ore copper is regulated by the richness of the
ore, the quality of the metal it contains, and the wants of the smelters, ores
from the same mine and containing metal of the same quality sometimes.
obtaining a different price for the ore copper. The miner, you are aware,
has nothing to do but to submit. I believe the practice in Cornish mines is
to advance 'subsist' to the tributers after their ores have been sampled and
weighed and the produces obtained. An approximation is then made of the
value of their ore from the standard of the most recent sale, and a certain
proportion of the approximated earnings thus obtained is then paid the men
in advance. Both agents and men can generally estimate the value of their
ore sufficiently near for this purpose.
"I am not aware of there being any rules or tables in existence for making
up the amounts in advance, as the final settlement or pay-day does not take
CHAP. III.]
ESTIMATION OF LEAD ORES.
685
place until after the ores are sold and a sufficient time for making up the
accounts.
"The only tables I am acquainted with at all relating to this portion of the
mine accountant's duty are Davey's, Easall's, Provis', & Whitburn's tables
for copper, and Captain Charles Thomas & Tregonning's for tin."
Standards at Par.-Two standards may be said to be proportionate or at
par, when the same price per ton for fine copper of equal quality is the base
in each; thus, if the copper in each of two parcels be of equal quality, but
the returning charges on one parcel be different from those on the other,
each may have a different standard, yet both be at "par," or on an equality
with respect to the market.
Again, if two parcels contain copper differing in quality, each may have
a different standard, and yet be at "par," or may have the same standard
and not both be at par.
When the standard and produce of one parcel of ore are given, and also
the produce of another, to find its standard-
Divide the returning charges of the first parcel by the produce, and
subtract the quotient from the given standard; reserve this difference; then
divide the returning charges of the second parcel by its produce and add this
quotient to the reserved difference; the sum will be the standard required.
To find the rise or fall in the standard at the ticketing.
From the given standard and produce of one week's sale, and the given
produce of another week's sale, find the standard at par for such sale by the
former rule; then, if this standard agrees with that of the last sale, the
market is at par; if not, the difference will show the rise or fall.
Estimation of Lead Ores.-The deductions usually made are for waste of
ore, for loss in smelting, for the charges on freight and carriage, and for coals,
and the other expenses incurred by the smelter, to which must be added the
profits claimed by the smelter.
Nearly all ores of lead contain silver.
added to the value of the lead in the ore.
any silver in the ore unless it exceeds 5 ozs. per ton of lead.
The returning charges are from £2 to £3
The value of that silver should be
No addition, however, is made for
freight, coals, and the smelter's profit.
per ton; this includes carriage,
In the lead mines of Cornwall and Wales the tributers raise the ores at a
given price per ton, and the adventurers generally dress it, for which the
men pay from 20s. to 40s. per ton, according to the quality of the stuff. The
ore is brought to a certain produce agreed on, or a deduction is made for
the deficiency. 21 cwts. dry weight is always considered as the ton.
In Cumberland the miners estimate the value of their orcs by the bing
of 8 cwts., reckoning so many bings per "shift," according to the quality
of the ore, or bouse, as the ore from the mine is called.*
A "shift," is the quantity contained in six or eight waggons, and amount
to about 240 kibbles of 14 quarts each. Each waggon in a six-waggon
"shift" contains 40 such kibbles; while in an eight-waggon "shift" each
waggon contains only 30 kibbles. The ore is dressed at a fixed price per
bing, according to quality.
*
“Bouse is that part of the vein that, in cutting the small or lesser sort of ore, cannot be separated
from it."-Miners' Dictionary, by William Hooson, a Derbyshire miner.
686
[BOOK III.
PRACTICAL MINING.
CHARGES FOR DRESSING LEAD ORE.
Bouse, or ore stuff, containing a bing per shift
•
s. d.
:)
""
""
""
I bing
I
223
2호
​3/1/10
4
""
""
""
These prices range from 12s. to £1 35. 9d. per ton.
9
6 per bing.
6 3
""
5 0
4 4
3 II
""
3 7
3 5
""
3 3
Valuing the Ore in the Vein.-The miner estimates that a vein of solid
lead ore 1 inch wide will produce 1 bing 3 cwts. 2 qrs. 24 lbs. 8 ozs., or
about 1 bing 3 cwts. of lead ore per square fathom; this is equal to 11 cwts.
2 qrs. 24 lbs. 8 ozs.
Value of Ground.—It is important that the agent of a miner should be
enabled to find the weight of any ore per square fathom in a vein of given
thickness. The weight of the ore may be approximated to form its specific
gravity and the average size of the vein when this is solid; frequently,
however, other substances are associated with the ores in the vein, or the
vein itself is not solid, and therefore the judgment of the agent is put to a
severe test. Sometimes the ores of copper are sold with mixture of silicious
matter; the specific gravity is then the best guide.
The ores of tin and lead are nearly always freed from the waste, then the
specific gravity of the waste may be omitted.
The following table, constructed by Dr. Rickard, gives the solid feet of
the most usual metals forming the matrices of the veins in which they occur.
To find the weight of ore per square fathom in a vein, multiply the number
opposite the ore by the number of cubic feet in a square fathom of the vein
at a given thickness. If a portion of the matrix be taken with the ore, the
average weight of one foot should be taken.
A vein 6 feet square and 1 inch thick will measure 3 cubic feet; there-
fore to find the cubic feet multiply the thickness in inches by 3.
Metals and Ores.
Weight.
Metals and Ores.
Weight.
GOLD. Native .
1230
750
ANTIMONY. Sulphide
281.25
Oxide.
""
345.12
SILVER. Native
643.75
MANGANESE
212.5
""
Vitreous
Red.
•
""
449'37
362.5
""
Binoxide
Wad
300'0
•
""
231.25
Horn.
COPPER. Native
Vitreous
>>
287.5
525
543'75
Psilomelan
250'
"
Pyrites
259'37
""
""
Purple
312.5
""
Gray.
296.87
NICKEL. Arsenical
Glance
Ton white
COBALT.
IRON. Native
•
Sulphide
450'25
281.25
•
381.25
400*
456.25
Red
""
•
375°
""
Pyrites
Malachite
250°
""
Magnetic ores
500'
512.5
TIN. Oxide
406.75
Arsenical
581.25
""
Sulphide.
268.75
LEAD. Native.
709'37
Hæmatite brown
URANIUM.
225.0
Pitch blende.
404.73
""
Sulphide, Galena.
468.75
BARYTA. Heavy spar
268.75
Carbonate
403'75
Carbonate
do. nearly.
ZINC.
Blende
250'
LIME. Calc-spar
156.25
Red oxide
337.5
FLUOR. Spar.
196.25
Carbonate
268.75
SILICA. Quartz
162'5
ANTIMONY. Native.
412.5
CHAPTER IV.
DRESSING OF METALLIFEROUS ORES-PREPARATION FOR THE SMELTER.
THE dressing of ores consists in effecting a mechanical separation of
earthy matter or gangue from metalliferous products. The conditions to
be observed are to effect the operations cheaply and to obtain the largest
amount of ore possible. To this end certain metalliferous ores may be
sufficiently massive, and pure in themselves, to be ready for the smelting
furnace, after the mere operation has been performed of picking out the
pieces of gangue with which they may be associated. Generally, however,
the "vein-stuff” sent to the dressing-floors includes (1) solid or "prill" ore,
(2) mixed or "dredge" ore, (3) fine ore or "smalls." Copper, Lead, Zinc,
and Pyritic ores are usually composed of these several varieties of stuff,
but in "tinstone" the particles of oxide of tin are usually so small, and so
thoroughly diffused with gangue, as to place it within the category of
dredge stuff, although this term is never substituted for tinstone by
the tin-miner. To separate metalliferous substances from vein-stuff by
the combined action of machinery and water recourse must be had to
the crushing or stamping mill as well as to the sizing trommel, classi-
fier, jigger, and buddle. Before referring to inventions comprising modern
dressing machinery, it is desirable to observe that dressing or separating
ore from veinstone can only be effected by adhering to the principle of
sizing grains of different densities into grains of equal volume, or otherwise
classifying grains of equal velocities of fall into grains of different dimensions.
Somehow or other this result must be accomplished, either by a direct or
indirect method, before light grains can be separated from heavy ones, or
grains of equal fall in water can be isolated from large and small ones.
Forty years ago or more the inclined screen and hand riddle comprised the
principal sizing apparatus for large-grained stuff, but jigger, buddle work,
and slimes were only indirectly sized and concentrated in the dressing
appliances themselves. Even now in Cornwall, indirect classification is
pursued in the dressing of tinstone; the "middle" or mixed tin product
undergoing a rude kind of classification and a series of concentrations to
afford "heads" or merchantable black tin. The distinctive method of
dressing prevailing in Germany in the sixteenth century was doubtless
introduced into this country by Germans. About the year 1562 Queen
Elizabeth, acting on the advice of her Council, sent to Germany for some
experienced miners to explore the mineral districts of England and Wales,
and upon their arrival granted them a monopoly of all the mines in Wales
and eight English counties. Later on, in 1565, all the mines and minerals
688
[BOOK 111.
PRACTICAL MINING.
in the remainder of the kingdom, and in the "English pale” in Ireland,
were granted to another German co-partnery, so that at this time the
mining operations of the kingdom were—perhaps with the exception of the
tin mines of Cornwall-under the direction of, if not actually worked by,
German miners. In 1583 "Dutche" miners were employed in developing
lead and copper mines in Cornwall. Not only is there ample evidence of
the large employment of Germans in the mines and smelting works of this
country in the sixteenth century, but the dressing apparatus known to be
in use down to the end of the succeeding century were similar to those illus-
trated in Agricola's work "De re Metallica," published at Basle in 1546.
This writer, whose real name was Bauer, and who resided in the Saxon.
Erzgeberge, in his eighth book of the work referred to, describes and illus-
trates the picking-table, &c. Descriptions and illustrations of the ore-
dressing processes followed, and of the apparatus employed in this country,
which were but few in number until within recent years.
Carew gives a clear account of tin-dressing as practised in the year
1602. At that time "ragging, bucking, and cobbing hammers were used
to prepare the tin-stuff for the stamps, in which apparatus it was eventually
reduced; the black tin was then concentrated on 'green turves,' and vanned
or 'shogged' in a bowl to 'flit away' any earthy substance left." Carew's
quaint description may be reproduced entire :-
"As much almost dooth it exceede credite, that the tynne, for and in so
small quantitie digged vp with so great toyle, and passing afterwards thorow
the managing of so many hands, ere it come to sale, should be any way able
to acquite the cost; for being once brought aboue ground in the stone, it is
first broken in peeces with hammers and then carryed, either in waynes or
on horses backs, to a stamping-mill, where three, and in some places sixe
great logges of timber, bounde at the ends with yron, and lifted vp and
downe by a wheele driven with the water, doe break it smaller. The
streame, after it hath forsaken the mill, is made to fall by certainne degrees,
one somewhat distant from another, upon each of which, at every discent,
lyeth a green turfe, three or four foot square, and one foot thicke. On this
the tynner layeth a certayne portion of the sandie tynne, and with his shuell
softly tosseth the same to and fro, that through thus stirring the water which
runneth over it, may wash away the light earth from the tynne, which, of a
heauier substance, lyeth fast on the turfe. Hauing so cleansed one portion,
he setteth the same aside, and beginneth with another, vntill his labour take
end with his taske. After it is thus washed, they put the remnant into a
wooden dish, broad, flat, and round, being about two foote ouer, and having
two handles fastened at the sides by which they softly shogge the same to
and fro in the water between their legges, as they sit ouer it, untill what-
soever of the earthie substance that was left be flited away. Some of later
time with a sleighter inuention and lighter labour, doe cause certayne boyes
to stir it vp and down with their feete, which worketh the same effect; the
residue after this often cleansing, they calle black tynne. But sithence I
gathered sticks to the building of this poor nest, Sir Francis Godolphin
entertained a Duch mynerall-man, and, taking light from his experience,
but building thereon farre more profitable conclusions of his owne inuention,
CHAP. IV.]
BORLASE ON DRESSING ORES.
689
hath practised a more saving way in these matters, and, besides, made
tynne with good profit of that refuse which tynners rejected as nothing worth."
In 1758 Dr. Borlase, in his "Natural History of Cornwall," describes the
dressing of tin and copper ore as then practised in the western part of that
county.
After noticing that the richer sorts of ore were kept together under-
ground in the copper mines, he remarks: "What comes from the people
below," he says, "is re-examined as soon as it arrives at the mouth of the
shaft; the best is broken small with hammers, which they call spalling, or
brought away to the adjacent bucking-mills, where there are men ready to
bruise it upon a rock with a short bar of iron, and thence carried to the heap
of best ore, and what is not worthy of the first place is laid by to make
another sortment; the best small ore (which consists of the smaller frag-
ments of what has been broken and sorted before) is then washed and sifted
into a tub or keeve, as near to the shaft as possible (to prevent waste), first
through an iron sieve, or searce, called in Cornwall the "griddle," the
meases about an inch square; here the waste or barren stone, by washing,
is discovered and thrown away, while the copper in it, sorted into best and
dredged (that is streaked, spotted, powdered ore which requires a second
washing), and the larger pieces of ore of each sortment are thus divided:
what passes through the griddle is taken up out of the keeve and put
through another searce of smaller meash called the "jigging searce," which
has eight holes in every square inch; here, when it has been lifted up and
down, and turned round in the searce a few times (which they call jigging),
the waste will all rise to the top and settle in the middle like small sand,
and what remains underneath will be clean ore. The poorer sort, which
is the streaked or dredged ore, is carried from the mine to the next ad-
joining stream of water, where, in several pits made for the purpose called
the strakes, it is washed clean. All the richest bits of ore are then culled
from the rest by girls or boys, at the hire of 4d. per day, and the poorest
or most stony parts, which are not fit to be put with the picked ore, are
carried to a stamping-mill, there pounded and passed through a rough
grate. What ore remains in the forepart of the pit (into which the
pounded ore was washed from the stamps) is carried back to the jigging
searce and worked as before mentioned, but what runs off the hindmost
part of the pit and remains there in the second pit (similar to that in the tin.
pits), is slimy, and must be trunked, buddled, and tozed as the slimy tin.”
One hundred and seventy-six years after the date of Carew's publica-
tion, Pryce, in his work,* published in 1778, devotes two chapters to
the dressing of ores: the first, Book IV., entitled, "The Method
of Sampling and Vanning of Tin Stuff, with the Stamping, Burning or
Calcining, and Dressing the same, with the manner of Dressing the
Leavings, Loobs, &c.;" the second, being headed "Of Dressing Copper
and Lead Ores, and Sampling Copper Ores for Sale." The illustration
appended to the chapter on tin-dressing shows an overshot water-wheel,
six heads of stamps, catch-pits, jigging buddle, trunk, rack frame, and
kieve. Similar appliances are illustrated in Agricola's work, hence it
* "Mineralogia Cornubiensis.”
690
[BOOK III.
PRACTICAL MINING.
may be inferred that Sir Francis Godolphin rather applied the experience
of the "Dutche mynerall-man" than built "thereon farre more profitable
conclusions of his own inuention."
In 1821 Westgarth Forster published "A Treatise on a Section of
the Strata from Newcastle-upon-Tyne to the Mountain of Cross Fell in
Cumberland,” * and he has given a chapter "On the Washing and Dress-
ing of Lead Ores." He observes: "Metals are seldom found in a pure
state, gold, silver, and sometimes copper excepted.
The others usually
occur in the state of ores, that is united with sulphur or some other
mineralising substance and blended with a variety of extraneous matter so
as not to possess the ductility or other qualities of metals. When they are
procured in this state the first operation is to separate the ore, of whatever
kind it may be, from its bed or matrix." In the description of lead-dressing
which follows he refers to the washing-kiln and grate, to the crushing-mill,
stamping-mill, bucker, hand-sieve, brake-sieve, running, stirring, and
nicking buddle, dolly-tub, slime-pits and hush-gullies, and he illustrates a
tripple roller crushing-mill, stamping-mill, flat buddle, brake-sieve, trunk-
buddle, stirring and nicking buddles, and dolly-tub. In reference to
jigging this writer makes the following pertinent observations: "The
washers put what they call a bedding upon the bottom of the sieve in
order to prevent the smiddum (rough ore) from passing too quickly
through. It must be observed that, owing to the superior specific gravity
of the particles of ore contained in this mass, they pass through the bedding
and sieve while the operation of braking or tilting is going on, and the particles
of stone, spar, &c., remain above the bedding, which are scraped off with
the limp." And then he is careful to explain "that the bedding consists of
a quantity of the smallest of the sieve ore laid on the bottom of the sieve
in the form of a layer about two inches thick, and when the sieve is work-
ing the shaking of it by the boy at the end of the lever or brake causes
the particles of ore that are among the tails to pass through the bedding and
openings of the sieve into the tub, the bedding not being that close to
prevent the ore from passing through it. This bedding, and the mechanical
opening of the grains by means of pistons or plungers reciprocating in
water, form the essential features of "fine sand" continuous jiggers in use
at this time, but instead of removing the "tails" or "waste" by means of a
limp it is drifted away by a stream of water running over the sieves.
Various improvements in the washing of lead ore seem to have been intro-
duced in the first twenty years of this century. During that period the
crushing-mill and brake-sieve were evidently introduced into the mines of
Cumberland and Derbyshire.†
In April, 1831, John Taylor, F.R.S., Treasurer of the Geological Society,
contributed to the "Quarterly Mining Review" a paper entitled, "Notice on
some Improvements in dressing Ores," wherein he observes: "I have often
thought that the operations for dressing ores have not received so much
attention among British miners as they deserve, and the cause of this
neglect it is perhaps not very difficult to trace.
* A new edition of this work has been recently published.
† In the second volume of the "Transactions of the Royal Geological Society of Cornwall," page
386, Borlase describes the preparation of tin in St. Just, especially with reference to the minerals of that
CHAP. IV.]
COPPER ORE DRESSING MACHINERY.
691
It will be found that the ores in Great Britain are generally rich, compared
with those of many districts on the Continent, and our miners have not,
therefore, been stimulated to attempt minute savings. Fuel for smelting is
also cheap and abundant in this country, therefore a concentration of the
metallic parts by fire is often better than that by mechanical methods, or
what we properly call dressing.
Notwithstanding that such reasons have some force in them, they are
not sufficient to warrant us in being inattentive to the subject, and it is
especially desirable to excite a more general and active pursuit of inquiry
and experiment.
In a valuable paper on the "Mining Districts of Cardiganshire and
Montgomeryshire," by Mr. Warington W. Smyth, published in the second
volume of the "Memoirs of the Geological Survey, 1848," a clear and com-
prehensive description is given of the dressing of lead ores at the Goginan
mines. Mr. Smyth illustrated the round buddle, the tye, the strake, and
the flat buddle. He also gave a plan of the Goginan dressing-floors.
In a small work published by Phillips and Darlington in 1857, entitled
"Records of Mining and Metallurgy," twenty-three pages were devoted to
"crushing and dressing machinery." The descriptive matter contains some
important statistics bearing on crushing and grinding mills, moisture in ore,
and cost of dressing ores, &c.
In 1857 M. Moissenet, then of the École des Mines, Paris, made an excur-
sion into Cornwall, and produced a valuable paper on the mechanical
preparation of tin. Not only did he visit several tin mines, but he investi-
gated and described each distinct process, and gave complete statistics of
the percentage weight of black tin contained in various products obtained
in different parts of individual machines. He also set out in a scientific
manner the order followed for effecting the enrichment of the black tin, and
appended to his paper three sheets of illustrations, which included forty-three
figures of the machinery and apparatus then in use. In 1866 M. Moissenet
published an equally complete paper on the dressing of lead ore at the
Lisburne mines, Cardiganshire, and illustrated it with thirty-two figures,
showing the floors and their dressing appliances.
""
In 1858 Mr. James Henderson, C.E., read a paper at the Institution of
Civil Engineers "On the Methods generally adopted in Cornwall in dressing
Tin and Copper Ores." This paper is highly interesting for the number
and completeness of the drawings which accompanied it; they are comprised
in two sheets, the first entitled "Tin Ore Dressing Machinery," the second,
Copper Ore Dressing Machinery." The tin apparatus includes excellent
illustrations of steam stamps, flat and round buddles, separators' hand
and rack frames, tossing, packing, and vanning tubs, strips, tye, Brunton's
calciner, burning-house furnace, and arsenic flues; while in the copper-
dressing appliances are included the slides, ragging and spalling, a picking-
table, hand and circular riddles, bucking-bench, cobbing, anvil, the brake-
sieve, steam-jigs, and crushing-mill. In the paper itself he briefly described
district. A detailed account of tin-dressing in the central mining district of Cornwall by the late William
Jory Henwood, is to be found in the "Transactions of the Geological Society of Cornwall," vol. iv. p. 145,
A.D. 1828. According to this writer trunking machinery was introduced into Cornish mines about the
year 1825.
Y Y
692
[BOOK III.
PRACTICAL MINING.
these various operations. Julius von Sparre, Bergmeister of Eisleben,
an accomplished mathematician, published in the Bergwerksfreund, in the
year 1858, "Contributions to the Art of dressing Ore." He may be fairly
said to have preceded Rittinger in many of his investigations, and to have
framed several important axioms of great practical value to the ore-dresser.
In 1860 John Darlington contributed to Ure's "Dictionary of Arts, Manu-
factures, and Mines," a lengthy paper entitled "Dressing of Ores." In the
edition published in 1875 the description with illustrations extended to
eighty pages, and in the supplement published in 1878 eleven additional
pages were given. In the "Mining and Smelting Magazine," a most valuable
work in six volumes, 1862 to 1864, edited by the late Henry Curwen Salmon,
many interesting papers are included on lead and tin-dressing machinery.
At a meeting of the members of the Institution of Civil Engineers, held
on the 5th of April, 1870, Mr. Thos. Sopwith, jun., read a lengthy paper on
"The Dressing of Lead Ores," in which he described the continuous jigger
as then constructed at Kalk, Cologne, and referred to a definite method of
sizing the crushed stuff by means of trommels.
Bergrath Gaetzschmann, of Freyberg, in his work "Die Aufbereitung,"
treats ore-dressing as an art. His work of 1,408 pages, with forty plates, and
an illustration of almost every dressing-machine known at the time of the
publication of the work (1864 to 1872), gives a complete history of the practice
of ore-dressing and apparatus employed since the middle of the sixteenth
century.
Rittinger's "Lehrbuch der Aufbereitungs Kunde," or Text Book of
the Science of Ore-dressing, was published in 1867 to 1870. This work
consists of 686 pages of text, and of an atlas containing forty-one
plates, which includes illustrations of all the important dressing-machines
then in use. Rittinger not only gave the fullest attention to the theoretical
and scientific axioms governing the art of dressing ore, but he may be said
to have completely formulated the scientific principles upon which successful
ore-dressing must ever be conducted.
On the 30th July, 1873, Mr. Henry I. Ferguson, of Truro, read at the
annual meeting of members of the Society of Mechanical Engineers, held
at Penzance, a comprehensive paper "On the Mechanical Appliances used
for dressing Tin and Copper Ores in Cornwall," which was accompanied
by valuable illustrations. At the same meeting Mr. Charles D. Taylor, of
Devoran-of the firm of John Taylor & Sons-described the tin stream works
in Restronguet Creek, near Truro, and a continuous jigger, impeller buddle,
and classifying box used in dressing oxide of tin. During the last six years.
many useful papers on tin stamping and dressing machinery have appeared
in the "
'Proceedings of the Mining Institute of Cornwall," notably by Mr.
R. H. Williams, of Cuddra, St. Austell, the late Mr. John Hocking, Messrs.
R. A. Varden, M. Loam, W. Teague, jun., and W. Husband, of Hayle. The
latter gentleman has also given a valuable paper on "Stamping Machinery."
In
Mr. J. M. Cazin, of New York, contributed a series of papers,*
entitled "Dynamical Metallurgy, or Mechanical Ore Concentration."
his introductory remarks the following observations occur: "Dynamical
Mining Record," vols. x. and xi.
*
CHAP. IV.]
DYNAMICAL METALLURGY.
693
metallurgy attempts the qualitative increase in value by arranging (moving)
the components of minerals so as to (physically) separate and collect the
valuable minerals from those bearing no value, without attempting any
change in the chemical (elementary) constitution either of the total (ore)
or of the parts. The products are a local concentration of particles of
value and a decrease in their intermixture with parts having little if any
value.
"The methods of chemical metallurgy are called either wet or dry
processes-dry when heat is applied, and wet when liquids are applied.
Dry processes applied in chemical metallurgy are roasting, smelting,
sublimation, distillation, evaporation, and crystallization. Wet processes
applied in chemical metallurgy are amalgamation, extraction, precipitation,
cementation, and solution. Both these dry and wet processes are called
"reduction." The methods of dynamical metallurgy are likewise called
either dry or wet processes-dry (pneumatic) when air is applied as the
dynamical medium, and wet when water or any other liquid is applied as
the dynamical medium for changing the local arrangement of particles
constituting the mineral (ore).
"The name of dynamical metallurgy has been introduced by me because
all other names formerly applied to this science and art are more or less
deficient in their meaning. In practice, nevertheless, their use may well be
preserved for what they mean, namely, mechanical ore concentration, ore
separation, or ore dressing."
Cazin next proceeds to develop "theories of dynamical metallurgy," and
assigns the merit of extending our knowledge of the existing relative action
of liquids, and submerged solids, to Von Sparre, Von Dem-Borne, and to
P. von Rittinger.
Among the chief mechanical inventions introduced during the present
century are the crushing-mill, stone-breaker, sizing-trommel, classifier,
continuous jigger, round buddle, and automatic dead frame. It is impossible
to state the circumstances which led up, as it were, to the several inventions,
but the names of one or two individuals who assiduously promoted the art
of dressing and mining deserve to be recorded and held in honourable
remembrance.
About the year 1796 Mr. John Taylor, the founder of the firm of Messrs.
John Taylor and Sons, took charge of Wheal Friendship in Devonshire.
Among other inventions applicable to mining he introduced the crushing-
mill in 1806 at the Crowndale copper mines, near Tavistock. At that
time the price of copper was high, and the Crowndale ore occurring
much intermixed with veinstone, the amount of labour being then insuf-
ficient to dress the stuff, Mr. Taylor took two lengths of cast-iron pipe
of 16 or 18 inches diameter, and made these serve as cylinders or rolls.
As this primitive crusher gave satisfactory results, properly-constructed
mills were subsequently made and employed in the eastern part of Cornwall
near St. Austell, especially at Pembroke, Lanescot, Fowey Consols, and East
Crennis mines.
The first crushing-mill in North Wales was erected at the Halkin mines
in 1823 by Mr. John Taylor, and in 1831 his son, the late Mr. Richard Taylor,
Y Y 2
694
[BOOK III.
PRACTICAL MINING.
introduced the crushing-mill into the Consolidated mines, Gwennap. From
that time to the present, the roller crushing-mill has formed the principal
apparatus for reducing mixed lead and copper ores for the jigger, buddle,
and other concentrating apparatus. The tumbling-shafts and weight-levers
to keep the rolls together, the riddle under the rolls for dividing the stuff
into jigger and crusher work, and the raft-wheel for returning the latter
product to the rolls, were applied by Cornish engineers.
1
The first jigging-machine erected in Cornwall was introduced by the
late Mr. Richard Taylor at the Consolidated mines, Gwennap, in the
year 1831. At these mines considerable dislike was manifested towards the
mechanical jigger. It was anticipated that all the persons then engaged in
jigging the ores would be thrown out of employment and starved, and it was
a matter of some difficulty to convince the people of the inefficiency of the
old method, and that a great deal of valuable stuff was lost through its use.
Two highly important improvements in mechanical jigging were made
between the years 1828 and 1830. One by the late Thomas Petherick,
manager of Lanescot and Fowey Consols mines, near St. Blazey; the other,
probably under the auspices of Mr. Taylor the elder, in one of the Tavistock
mines. Petherick's hydraulic jigger consisted of a movable plunger, fixed
sieves, an automatic hopper, and receptacles beneath the sieves for collecting
the ore.
The waste was removed from the sieves by means of a limp, and
in this respect it differed only from the automatic action of the modern
continuous jigger.
In 1828 a revolution in the system of jigging is said to have been effected
in Hungary by an engineer named Tutsenak, who appears to have successfully
devised a mechanical jigger.
The triple roll crushing-mill was introduced in the North of England;
while the disc springs, of india-rubber and iron, and the arrangement for
maintaining a constant pressure on the rolls at any given distance from
their respective faces, are details due to German engineers.
The stone-breaker was invented in America in 1858 by Mr. Blake, since
which time this machine has found its way into the chief mining and
metallurgical establishments of every country. Some modifications of parts
have been made by various English, French, and German engineers, but
they have all failed in devising a machine capable of superseding the main
part of Blake's invention-the use of jaw-pieces for breaking large stones
into stones of small dimensions.
Jigging was formerly done with a small common round sieve by boys,
who had to work stooping, so that their heads were down near the surface of
the water-tank in which the sieves were used, these tanks, too, being sunk
in the ground. The operation was both laborious and tedious, and many
hands were required to get through large quantities of stuff. In Derbyshire,
and in the lead districts which derived their practice chiefly from that county,
an improved jigging apparatus was used early in the present century. A
sieve was hung upon the end of a lever, and motion at once given to a large
portion of stuff held in the sieve. Improvements in mounting the sieve
were introduced at Wheal Betsey—a lead mine near Tavistock-but were not
applied to copper ores until a considerable period afterwards. The modifi-
CHAP. IV.]
CONTINUOUS FIGGING-MACHINES.
695
cations in the arrangement of the lever-jigger were probably made between
the years 1820 and 1830.
About the year 1830 Captain Barratt, of Grassington mines, in York-
shire, had hung the lever-sieve so that it could be worked mechanically. The
late Mr. John Taylor the elder, writing to the "Quarterly Mining Review" in
April, 1831, after noticing Petherick's stationary sieves, states: "The other
method has been that of giving motion to the sieves hanging in water, in
the same way as the Derbyshire break-sieves do. This has been admirably
accomplished by Captain Barratt, of Grassington, where several sieves
are worked by one small water-wheel, and the effect is excellent, and the
expense of the process is so much reduced, that very poor work is now
returned with profit that would not have paid upon the old plan."
On the 23rd June, 1843, Nicholas Troughton patented what appears to
have been the first continuous jigger. The arrangement consisted of a long
hutch, a sieve suspended to a rocking shaft, a driving eccentric and a
fly-wheel. The sieve was set in a deep frame, and divided into four
triangular-shaped receptacles. It was also fitted with two flap valves. The
stuff was passed to the first of the receptacles from a hopper set on the top
of the hutch and over the sieve. By means of the valves referred to, and the
"jig" movement imparted to the sieves, the stuff was not only "settled"
and classified, but the water admitted through the valves during the
downward movement of the piston swept the stuff forward, separating the
waste from the ore and dredge work.
In 1864 Henry C. Salmon published, in the volume of the "Mining and
Smelting Magazine,” a description with illustrations of a "new continuous
jigging-machine of the Harz," and remarked: "Until very recently both the
rich and poor lead ores of the mines of the Upper Harz, of a size ranging from
one-twelfth to one-twenty-fifth of an inch, had been dressed by means of the
ordinary strake, tye, and buddle, a process which, however simple in itself,
consumes an undue proportion of time and labour, and greatly depends
besides for its effectiveness on the attention of the attendant. For the last
two years this process has been superseded with the most satisfactory results
for ores of the size mentioned by a continuous jigging-machine." The
machine consisted of a piston and stationary sieve, the latter slightly inclined
downward to a point at the centre, with vertical discharge-pipe from the
centre of the sieve, and covered with an adjustable cylinder for regulating the
rate of discharging the concentrated ore. The late Mr. John Hunt patented
in this country, on the 8th of March, 1866, a continuous jigging-machine.
Several machines were constructed by him, which consisted of two sieves
divided by a bridge, two ore chambers, and a pipe for delivering water to the
apparatus. In Hunt's specification some of the functions of the fine-sand
jigger claimed by later patentees are described. At the present time
continuous jiggers include a variety of forms, some good and others bad in
principle; but Casin's observations on the value of a good continuous jigger
are to the effect that with a properly-constructed and well-regulated jigger,
with an automatic "feed" and "discharge" of the waste and concentrated
ore, no praise of the machine can be overdone. A competent ore-dresser can
make it work absolutely at will to meet the requirements of any special case.
696
[BOOK III.
PRACTICAL MINING.
The elements of action subject to modification are—(1) a given volume of
water may be continuously supplied to the first sieve; (2) the volume of
water may be increased to the second and third sieves; (3) water may be
supplied under or over each sieve and piston; (4) the quality and quantity
of bedding on each of the sieves may be modified at will; (5) the number
of strokes per minute and length of stroke may be arranged to suit particular
kinds of stuff; (6) the length of stroke of each piston may be set according
to the necessities of the case.
The merit of inventing the plunger continuous jigger belongs, according
to Gaetzschmann and other German writers, to Vogl of Joachimsthall and
Wimmer of Clausthal, who brought out their plans almost simultaneously
about the year 1850.
Sizing trommels for sorting ores for jiggers were employed at Great
Devon Consols by Isaac Richards in the year 1856. The highest develop-
ment of the trommel system is to be found in Germany, where the most
accurate sizing of ore prevails, and where trommels of all kinds may be
found. Many years ago Mr. Brunton invented a separator for the purpose
of sizing stuff by letting it fall through a column of water in a cylinder about
10 feet high, which he placed over a rotating trough divided into a series of
compartments or cells. As this trough rotated, the cells within it were
brought successively under an orifice at the bottom of the cylinder, the
largest grains, falling most rapidly through the column of the water, reached
the bottom of the cylinder first, and found their way into a cell, and the
trough, travelling forwards, the next size fell into a second cell, and so on.
The trough was of an annular form, and made one revolution for each charge
of tin stuff to the cylinder. A separator of this construction was set to
work at Tincroft, but the results were not satisfactory.
Later, Bergmeister Hundt, of Seigen, endeavoured to give effect to the
idea of dressing ore by an almost similar kind of apparatus, but he also
appears not to have realised satisfactory results. In 1856 Richards employed
a classifier at the Great Devon Consols; and Captain Ball, of the Cardiganshire
mines, who had effected many improvements in the details of dressing
machinery, introduced the classifier into the lead-dressing floors of a mine
near Aberystwith. This classifier consisted of a rectangular-shaped box and
a vertical launder for conveying water under pressure to the box itself. The
more scientifically constructed spitzkasten, or triangular-shaped box, is of
German origin. The separating cone, a series of which may be made to con-
stitute a classifier, was introduced by Mr. Borlase of Redruth, at Allenheads,
in Cumberland, about the year 1857. The round convex buddle was first used
in Cardiganshire about the year 1848. Subsequently, Phillips and Darlington
designed a concave buddle, and later, in 1856, Hundt of Seigen introduced
a concave buddle into some of the neighbouring mines of that place.
Borlase also modified the details both of the concave and convex buddles.
An automatic dead frame, now a distinctive feature on the Cornish tin
floors, was designed by Vincent and introduced at Cook's Kitchen about the
year 1860.
Railroads were only generally used on the dressing-floors of mines of this
country from the year 1818.
CHAP. IV.]
THE TRANSPORT OF ORES.
697
On the subject of the transport of ore and stuff from one point to
another, Mr. John Taylor the elder, writing in 1831, makes the following
remarks:
"The transport in various directions of large masses of stuff used to be
attended with considerable charges; these are now much reduced, not only
by the means that the railroads themselves afford, but also in many cases
from improvements in the arrangement of the different processes on the
dressing-floors, which have been suggested by the use of the railroads, and
which have made important alterations by avoiding that handling back-
wards and forwards which was too much the former practice, and which
of itself occasioned considerable expense. One of the best instances of
arrangements of this sort, connected by well-constructed railroads, is to be
seen at the mines belonging to the Duke of Devonshire at Grassington, and
which reflects much credit upon Captain Barratt, the resident agent, who
has laid out the most systematic plan of ore-dressing that I know of.”
Upon the subject of slime-dressing Mr. J. Taylor wrote (1831): “In the
first place I may notice that, some years ago, all the slimes from the ores in
the lead mines of the North of England were suffered to be carried off by
the water, and nothing was extracted from them until a man called Tratham,
from Cornwall, acquainted with tin-dressing, wandered thither and began to
dress them, the art of doing which remained for a long time confined to him
and his family, and one of his sons is still working in this way, on the floors
originally constructed by his father, at Nenthead, on Alston Moor, where,
indeed, is still the only stamping-mill that I have seen in that district. The
value of the ores in the slimes is, however, now well understood there; and
we see, in the Lead Company's Works in particular, a system of well-
arranged slime-pits for catching them, and some well-conducted processes
for dressing them."
With the foregoing preliminary observations it may be desirable to
proceed to the consideration of the various hypotheses bearing generally on
the mechanical preparation of ores for the smelter, to describe the more
important varieties of dressing machinery, and to refer to the ores to which
they are applied.
(1.) Metalliferous ores, obtained from lodes or veins, are generally
associated with ROCK and mineral substances known as ganguc or vein-
stone.
The ROCK, usually of a fragmentary character, is mostly similar to that
enclosing the lode, while the mineral substances are generally constituents
of the enclosing rock, or of rocks in fissure connection, with the lode itself.
Although a lode may be known as being productive of a particular ore,
yet it may also contain two or three other distinct ores. Galena (sulphide
of lead) is frequently associated with blende (sulphide of zinc), and occa-
sionally with iron and copper pyrites. Copper ore also exists in close con-
nection with oxide of tin, and oxide of tin with wolfram or tungstate of
iron.
In many lodes an ore exists distinct in itself [galena or copper pyrites],
in others, two or more ores are closely aggregated together [sulphide
of silver and sulphide of lead], or, as in the case of "Bluestone" of the Isle
698
[BOOK III.
PRACTICAL MINING.
of Anglesea, which is a mineral composed of sulphide of lead, zinc, copper,
silver, and a little gold.
Ores are either massive or mixed. In the first division the ore is of con-
siderable size, and almost free and distinct from veinstone, an example
being the great veins of pyrites at Rio Tinto, while mixed ore may be
subdivided into ore associated with veinstone in such manner as to be
readily detached from the latter by means of a cobbing hammer; or ore so
intimately intermixed with the veinstone as to render crushing or stamping
machinery necessary for the purpose of effecting its concentration.
Metallic ores are either comparatively hard or soft [Iron pyrites,
H=60-6·5; Galena, H=2.0-2.5], these terms being used in their ordinary
sense, or friable, as in the case of black oxide of copper. Ores may also
occur in a granular form, as the lead ore of commerce (Rhenish Prussia)
[grains of galena and quartz feebly cemented together], or as pisolitic iron
ore from the iron mines near Belfast. In order to more readily compare or
identify ores they have been grouped into ten divisions of hardness, ranging
from talc, with a hardness of 1, to the diamond with a hardness of 10. When
more exact means are not available an approximation of the hardness is
given by the following tests: The hardness of the finger-nail is about 25,
that of copper 3, and that of white iron 4'5. Window glass varies from 50
to 5'5, and a file from 6 to 7; while flint has a hardness of 7. Of the few
minerals that exceed flint in hardness corundum or emery (hardness 9) is
the only one that need be noticed here.
The relative hardness and brittleness of one ore with another, and with
the associated veinstone, is a point of economic importance in their
mechanical enrichment. Sulphide of silver, H 20-25, and lead ore,
H 2.5, are often found in mechanical combination with each other, and
when such ore is reduced and concentrated in water, an appreciable portion
of the more brittle and precious ore [Aq.2 S.] frequently floats away and is lost.
Brittleness must not be mistaken for hardness. Many minerals, too hard
to be scratched, are readily powdered by the edge of the knife, while other
minerals of a minute crystalline or foliaceous structure yield, when broken,
a considerable quantity of scale-like dust [dust of fracture.]
In order to smelt ores successfully and economically in the furnace, it is
in most cases necessary to free the same previous to their reduction from
adhering or mixed veinstone; this process, a mechanical one, is technically
known as "ore-dressing."
Specific Gravity of Metals, Minerals, and Earthy Substances.-By the
specific gravity of a substance is understood its weight as compared with
that of an equal bulk of some other body taken as a standard.* Water is
always the standard of comparison for minerals; thus the specific gravity of
water is 1, that of gold is 19.3, meaning that, bulk for bulk, gold is 19.3 times
heavier than water.
The weight of a cubic foot of water is 62.425 lbs., and the specific gravity
of galena is 7.5. If, therefore, it should be required to determine the weight
of a cubic foot of this ore it will only be necessary to multiply 62.425 by 7*5,
giving 468 18 lbs. The weight of any other ore or mineral substance may
* For Table of Specific Gravities, see Appendix.
CHAP. IV.]
THE SPECIFIC GRAVITY OF MINERALS.
699
in like manner be ascertained. The specific gravity of quartz is 2·6. If
2.6 be multiplied by 62.425, the weight of a cubic foot of this mineral is also
obtained.
The mineral to be examined for its specific gravity should be free, as far
as possible, from foreign substances, and it should not have many hollow or
drusey cavities.
METHOD WITH HYDROSTATIC BALANCE (FIG. 191).
(a) Weigh the mineral carefully in an
ordinary balance.
(6) Suspend the mineral by a horse-
hair, and let the mineral dip
well below the surface of the
water in some convenient vessel
and again weigh it, taking care
to dislodge any air bubbles that
may be seen on the specimen.
(c) Subtract the weight from that
of, the difference will be the
weight of a bulk of water exactly
equal to the specimen.
(d) Divide the weight by the differ-
ence, the quotient will be the
specific gravity.
Example. (a) Weight in air
(b)
57 I grs.
""
""
water. 42°4 "
•
14.7,
(c) Difference
•
(d) Then 57.1 divided by 1.47
gives 3.88 as the specific
gravity of the mineral.
Fig. 191.
METHOD WITH SPECIFIC GRAVITY BOTTLE.
In cases where but small fragments of a substance can be obtained, an
instrument, which can be readily procured from any good philosophical
instrument maker, is most conveniently employed. This consists of a small
bottle, of which the stopper is nicely fitted by grinding and is traversed by
a capillary tube, the stopper being so arranged that it cannot sink beyond a
line marked on the neck of the phial. By this means it is easy to obtain
a constant weight of water in the instrument, since, if it be filled beyond the
line and the stopper afterwards forced into it, the superfluous liquid will
escape through the capillary tube and the bottle remain exactly full.
(a) Let the bottle hold a given weight of water, say 500 grains, fill the bottle with water, insert the
stopper and wipe it dry, then make a counterpoise of exactly the weight of the filled bottle.
(6) Weigh off any convenient quantity of the specimen less than the capacity of the bottle, and in
fragments sufficiently small to go in.
(c) Put the weighed fragments into the bottle, taking care to lose none. Now as the bottle was
already filled with water, some will during this operation run out, whilst it is evident that the
water thus removed must be of exactly the same bulk as the mineral introduced. Having again
inserted the stopper, and weighed the bottle, it will be found that the counterpoise, together with
a smaller number of weights than those used to balance the fragments in the scale pan, will
produce equilibrium.
(d) The difference will be the weight of the displaced water or, of the bulk of water, equal to the
specimen.
(e) Divide the weight of the mineral in (b) by the difference (d), the result will be the specific gravity
required.
Example.-Three hundred and fifty grains of sand were carefully
weighed and placed in the bottle, when, besides the counterpoise, 241 grains
were required to produce equilibrium.
700
PRACTICAL MINING.
[BOOK III.
(b) Weight of sand in air
(c)
water
""
350 grains.
241
""
(d) Difference
109
(e) Then 350 divided by 109 gives 3.21 specific gravity of the sand.
In order to determine approximately if grains of mineral and ore will
separate from each other through the medium of water, it is sometimes
advantageous to consult a table of specific gravities, for which see the
Appendix.
By consulting the table of hardness and specific gravity of metallic ores
and minerals the following points may be approximately determined :—
(a) Whether an ore can be separated from its gangue and veinstone both readily and cheaply, and if
by means of simple dressing appliances.
(b) If a serious loss of ore is likely to occur in so separating it from its gangue or from the minerals
with which it may be intermixed or associated.
(c) Grains of galena and quartz can be readily separated by water dressing, since the specific gravity
of the former is 7.5 and the latter 2.6, a difference of 4'9. But if ore consisting of copper
pyrites, blende, and carbonate of iron associated together be treated in a similar manner, the
separation will be very imperfect and correspondingly unsatisfactory.
Copper Pyrites specific gravity
Blende
Carbonate of Iron.
4.15
4'02 Difference 0.13
4.I
0.05
""
These figures show that the specific weights of each of these ores in
water differ but slightly from each other, hence if the grains of one ore
should present a little more surface than the grains of another, which is
practically unavoidable, or even if the grains should have an equal amount of
surface and the mechanical treatment be but slightly imperfect, the attempt
to separate such ores will be rendered unsuccessful.
(a) Grains of galena [spec. grav, 7.5] associated with carbonate of lime
[spec. grav. 2·6] and Clay-Slate [spec. grav. 2·5] will not only separate readily
from the two latter substances when falling in water, but from the great
difference in density existing between grains of equal volume a considerable
variation of their relative sizes may be allowed without risk of obtaining an
unsatisfactory result. It therefore follows with such an admixture of ore
and veinstone that but few mechanical appliances will be required for the
concentration of the ore, and that the dressing process will be a short and
cheap one.
(6) Although the loss of ore occurring in water-dressing will depend
upon many circumstances, yet it is certain that if an ore be considerably
softer than its gangue and much less in its relative proportion to the latter
substance, the effect of crushing, pounding, or triturating the metalliferous
stone will be to reduce the ore into grains of lesser dimensions than those
constituting the detached matrix, to produce dust of fracture and slime, and
perhaps to bring a portion of the ore into a form in which the effect of
gravity, as manifested in the falling velocity of the grains, will be more than
neutralised by the mere movement of a feeble current of water.
Estimation of Ore and Loss in Dressing.-Ore stuff, when delivered to
the dressing-floors, will contain a given percentage and quantity of metal.
In concentrating ore more or less mixed with veinstone and rock, no matter
how carefully the process may be conducted, a metallic loss will always
occur. In order to determine the extent and percentage of this loss it will
CHAP. IV.]
PHYSICAL TREATMENT OF ORES.
701
be convenient to reduce a ton of ordinary metal to units, one hundred of
such units representing a ton, and, in the case of any given weight of
metalliferous stuff, to ascertain the number of units of metal which it may
contain.
In certain expressions employed in referring to this subject, percentages
of metal and units of metal are intended to mean one and the same thing.
Stuff assaying 3 per cent. gives also 3 units of metal; but if stuff should
assay 7 per cent. or 7 units of metal, and the dressing loss should be 31
units, the loss in this case will not be 3 per cent., but 3 units or 50 per cent.
of the initial quantity of metal present.
The percentage assay of a ton of ore is also the number of units of
metal contained in the ore; hence, if it be required to ascertain the number
of units and tons of metal contained in a given pile of stuff, it will be
sufficient to multiply the number of tons by the percentage-the result will
be the total number of units of metal therein-and then to divide the product
by 100, so as to obtain the tons and the decimal parts of a ton.
Ore stuff 3211 tons-Assay 3 per cent.
Then 3211 X3=9633 units of metal.
9633
96.33 tons of metal.
Example.
And
100
The loss in dressing is the difference between the quantity of metal
present in the initial ore and that which is found in the dressed product. If
3,211 tons of stuff afforded 96.33 units or 96.33 tons of metal, and after
dressing only 115 tons of ore of 75 per cent., the loss will be 1,008 units, or
equal to 10 per cent. of the initial quantity of metal.
Thus :-3211 tons of stuff at 3 per cent. —
115
""
ore at 75
9633 units.
=8625
Loss 1008
1008 X 100
Or
9633
10 per cent. of the initial quantity of metal in the undressed stuff.
The loss of metal which occurs in water-dressing will more or less depend,
as already to a certain extent indicated, upon certain physical and mechanical
conditions of the stuff itself.
Physical. Relative difference of densities in the ore and mineral to be
treated.
Relative hardness of one of the constituent ores with one another and
with the veinstone.
Relative degree of brittleness and proportion in which ore and veinstone
may be associated together, as well as the degree of "toughness" with
which the grains may adhere to each other previous to the reduction of the
stone.
Mechanical.-Nature and extent of the mechanical treatment to which
ores and veinstone may be subjected.
Examples of actual Losses of Metal-Copper Ore.-Blue and green car-
bonate of copper intermixed with hard quartz, clay, steatite, and jasperite.
Assay of 222 tons of stuff before reduction in stamps 33 per cent., or 33
units of metal per ton of stuff. Total number of units of copper contained
in stuff (222 × 3) 832, or 8 tons of metallic copper.
702
[BOOK III.
PRACTICAL MINING.
Mode of Treatment.—The stuff was crushed by Cornish stamps. Weight
of head, 5 cwts.; height of fall, 8 inches; diameter of gratehole, 2 millimetres.
Stuff passed through stamps' grates into strips, and twice buddled.
Ore obtained 6 tons,
which afforded
Tons
of
Units. Metal.
14 units of copper per ton or 84 0.84
Loss in dressing 216 tons 748 7:48
•
832 8.32
Stuff treated, 222 tons at
3 units of copper per ton
Units.
Tons
of
Metal.
832 or 8.32
832 or 8.32
Tailings.-The tailings, 216 tons, carried off 748 units of metal or
89% per cent. of the total quantity of copper present in 222 tons of stuff.
The ore was attached to the quartz in minute particles or films just in
sufficient quantity to slightly increase the density of the latter. Compara-
tively fine stamping was therefore a necessity, and in so detaching the ore it
was rendered more or less foliaceous, and formed scummy flecks on the
water passing through the dressing apparatus.
Sulphide of Lead.-This ore, finely and closely intermixed with iron
pyrites and oxide of iron, was subjected to various methods of enrichment.
In each case the assay of the stuff before treatment afforded 17 per cent. of
metal.
IO
""
Quantity by
Weight of Ore.
2 tons
Percentage Loss
of the Metal
originally present.
61 per cent.
39
57
4
2
•
410,
4
""
371/
""
50
410"
6,90
33
1099
16212
Quantity of Stuff by Weight.
10 tons washed and concentrated to
ΙΟ burnt, roasted, and concentrated
24
washed and concentrated
13.6 tons washed and concentrated
3∞∞
8
""
8
""
10
roasted, washed, and concentrated
""
3
Sulphide of lead, fine grain, partly dressed, assay, lead 42 per cent.,
silver 11 ounces per ton; 34 tons crushed and redressed obtained 14
tons, assay 54 per cent.; silver, 11 ounces per ton of ore.
In this example
the produce was raised 12 units per ton of ore, at a loss of 49 per cent. of the
quantity of lead, and 95 ounces of silver, originally present in the partially-
dressed ore. The money loss attending the experiment, after making the
several charges and allowances incident to the metallurgic reduction, was
£91 14s., or £2 14s. per ton on the original weight.
Silver Orc.-Silver ores per se rarely exist in sufficient quantities to
render their treatment necessary by the common process of dressing. Such
ores are, however, frequently found in close combination with sulphide of
lead, antimony, or copper.
When sulphide of silver is present with sulphide of lead, the association
is probably a mechanical one, since it is found that the more the grains of
ore are broken and subjected to the action of a current of water, the greater
is the loss of sulphide of silver. The following results were obtained from
the enrichment of many thousand tons of fine grain sulphide of lead.
Cobbed or selected ore not dressed in water afforded 15.9 ozs. of silver per ton of ore.
Sieve raggings reduced and jigged
Ore and veinstone, crushed and jigged
Slimes from crushing rolls and jiggers
15.1
12. I
""
""
10'4
""
>>
CHAP. IV.]
THE ENRICHING OF VEIN STUFF.
703
The loss of silver in sieve raggings converted into slimes consequent on
a finer state of mechanical subdivision and treatment in water amounted to
(15°1 — 10'4) 476 ounces of silver per ton of ore. In this example the dressing
was well conducted, every care having been taken to obtain the maximum
quantity of cobbed ore, to size the stuff properly, and to limit its reduction
to the average size of grains so as to afford the greatest amount of
dressed ore.
Broadly stated, the loss of metal which will occur in the mechanical
treatment of ore and the cost of enrichment will be small—
If the ore is fairly hard and breaks into smaller pieces without producing
much dust of fracture.
If the ore is in itself of considerable density, and consists mostly of large
grains easily detached from a gangue of much lighter specific weight.
If the enriching operation is chiefly confined to hand-picking, and if only
a small proportion of the stuff sent to the floor is subjected to water
treatment.
Whilst the loss of ore and cost of dressing will be considerable-
If the constituents of the ore and veinstone are composed of very small
grains uniformly aggregated together.
If the ore and veinstone are nearly alike in density.
If the ore is so friable as to disintegrate into a powder by the absorption
and mechanical action of water.
If the ore is sparingly associated or intermixed with veinstone, or if
the veinstone is hard and the ore soft, or if both are subjected to severe
pounding action.
If the ore in itself bears a high percentage of metal—as in the case of
carbonate of copper, 57 per cent.-and simply stains the veinstone.
If a soft ore, thinly distributed or intermixed with hard veinstone, is
pounded so as to shatter instead of detaching the orey particles.
The loss which occurs in enriching of ore usually commences with
the crushing or reducing operation. In many cases ore is distributed or
associated with the veinstone so irregularly as to render the assay of a
sample drawn from a pile of vein stuff a very uncertain indication of its
metallic contents. It is, however, always a simple operation to take a sample
from the sand and slime tailings, and to determine with tolerable accuracy
the amount of metal they contain. Thus samples may be obtained in the
castaways from the coarse and fine sand jiggers, the buddles, and the fine
slime enriching tables.
A practical and useful method of ascertaining the approximate loss of
ore in tailings is to construct four sample boxes for the tailings from
coarse and fine sand jiggers, buddles, and slimes.
At the end of every month to sample and assay the contents of each box.
Some gangues, such as the white carbonate of lime and barytes, will
distinctly show if an appreciable quantity of lead or copper ore is present;
but the darker-coloured gangues or veinstones will not exhibit the ore so
readily.
In a large and well-conducted undertaking the tailings should frequently
be examined and periodically assayed. It will always be satisfactory to
704
[BOOK III.
PRACTICAL MINING.
know that the ore is obtained from the veinstone without incurring any
considerable loss, and that the enriching process is economically and well
conducted, while such results, carefully tabulated, will probably serve as an
incentive to still further progress and improvement.
ore.
High Percentage Ore Dressing.-The interest of the smelter and miner is
not relatively the same. The former seeks to obtain the richest ore for the
furnace, knowing it will afford the greatest weight of metal for the smallest
consumption of fuel and flux, and that a ton weight can be reduced as
quickly, and somewhat more cheaply, than a corresponding weight of poor
The miner, not always aware of these circumstances, but attracted by
the desirability of lessening transport and smelting charges, frequently
insists on high percentage ore dressing, that is, of enriching the ore to the
exclusion of most of the earthy matter, without estimating the loss of metal
which is thereby entailed. A simple illustration will show that the loss of
metal occurring in the dressing process must be considered and taken into
account, if the object is to obtain the greatest money value for the ore
contained in the original stuff.
Example. Take a pile of stuff, containing carbonate of copper, say 2,000 tons, assay 2 per cent., and
let 1,000 tons be dressed to afford ore containing 20 per cent. of metal and 1,000 tons treated in
like manner to yield a pile of ore assaying 30 per cent. of metal. Dressing cost 30s. and 40s. per
ton of ore respectively, transport and smelting cost or "returning charges" 90s. per ton of ore.
Stuff 1000 tons at 2 per cent. = 2000 units. Stuff 1000 tons at 2 per cent. 2000 units.
Dressed to afford 50)
Dressed to afford 25
tons of ore at 30
per cent.
Loss of ore
tons of ore at 20
per cent.
Loss of ore
1000 units.
1000
""
2000
750 units.
1250
2000
""
RELATIVE VALUE OF EACH PILE OF ORE.
50 tons 1000 units at 16s.
£800 0 0
Dressing 50 tons at 30s. £75 0
Returning charges at 90s. 225
225 O O
25 tons 750 units at 16s.
Dressing 25 tons at 40s. £50
Returning charges at 90s, 112
£600 o o
o
10
O
300 0
162 10 0
437 10 O
Loss on pile of 30 per cent. ore
62 IO O
£500 0 0
£500 0 0
In this example, although the dressing and returning charges of the
richer ore (162 10s.) is only a little more than one-half of that debited to
the 20 per cent. ore, yet the loss of money arising from the extra loss of
metal in obtaining the 30 per cent. is £62 10s. In such a case it is clear
that the stuff should be enriched so as to afford ore of the lower, and not
of the higher metal percentage.
As the necessity for sizing and classifying the smaller size of vein stuff
(crusher or stamps work) for the purpose of concentrating the ore grains
which it may contain has been adverted to, it will be desirable to define very
briefly the meaning of certain terms employed in connection with this
division of ore-dressing.
Stuff. By the term “stuff” is meant an admixture of grains of ore and
gangue, such as is obtainable from the crusher-rolls and stamps, and from
the operation of jigging, buddling, or other like operation.
CHAP. IV.]
VOLUMETRIC SIZING OF MINERALS.
705
Dimension of Grains.-The dimensions, or diameters, of grains of ore and
gangue are determined by the sieve or classifier, and are usually expressed
in
open terms, o to X, the first term, O, including grains of a minimum, and
the second term, X, grains of a maximum, diameter. For example, if the
minimum diameter of a set of the grains is known, say 2 mm., and the
maximum not known, the expression would be, 2 mm. to X, while if the
maximum diameter is known, say 10 mm., and the minimum unknown, the
converse expression would be used, viz. O to 10 mm.
Spheres and Grains.-The term " grains" is used in a sense synonymous
with spheres, from the fact that the holes in a trommel are usually round,
and that a sphere is an absolute figure; but grains of ore and gangue are
never round, but more or less irregular. At best they only approximate to
the figure of a sphere, the limit of approximation depending essentially
upon the structure or crystalline character of the minerals themselves.
Sizing.-Sizing consists of passing grains of stuff through a sieve, by
which a group of grains are obtained of equal volume (approximately), but
of different densities (volumetric sizing).
Classification consists of subjecting grains of different densities to the
action of a current of water, when a group of grains, differing in their
volumes but having equal velocities of fall (equivalents), are obtained.
Grains from Sieves and Classifiers.—Volumetric grains, or metalliferous
and mineral grains, of equal volume, but of different densities, falling
through water will separate from each other; in other words, one will fall
more rapidly than the other, whereas equivalents, or grains, which will differ
from each other in volume and density, will fall in a current of water with
equal velocity, and group themselves together at the bottom.
If such grains, having an equal velocity of fall in water and different
diameters be placed on a slightly inclined table (buddle or frame), and
exposed to the propelling action of a current of water, it will necessarily
follow that grains of the larger diameter will expose greater amount of
surfaces to the stream than grains of lesser diameter and greater weight.
The former will, therefore, move more rapidly than the latter, and a separa-
tion of the former will consequently be effected.
Sizing Minerals.-When the separation of mineral substances is to be
effected by the medium of water, trommels and classifiers must usually be
employed. The trommel is a round cylinder or conical-shaped drum,
perforated with holes, and is used for volumetric sizing, that is for dividing
rough stuff and coarse grains into groups of equal volume but differing from
each other in their density, while the classifier-a cylinder box or trough—
deals with grains of fine sand and slime, and resolves these grains into
"equivalents" or grains differing from each other in their volume but falling
through water with equal velocity. The rule for determining the relative
volume of grains of different densities, having the same velocity of fall in water,
is found by deducting the equivalent of water from the specific weight of the
substance and dividing the less into the greater. The density of tinstone
may be assumed to be 6 and that of the gangue 2.5. The remaining gravity,
when submerged in water, for tinstone is 5, and for the gangue 15, therefore
a sphere of a diameter 3:3, consisting of gangue, falls at an equal rate in
706
[BOOK III.
PRACTICAL MINING.
water with a sphere of tinstone of a diameter of 1
-
I
=
6 -
1 ) — 1 — 2·5 — 1
= 3.3.
Or, suppose a pile of stuff to consist of galena, blende, and quartz, what will
be the relative diameters of the grains having an equal velocity of fall
through water?—
Galena
Blende
Blende
Quartz
7·5—1—6·5) Thus
4'0-13'0
Diameter of Grains having equal Velocity of Fall
through Water.
6·5 — 2·1, or galena 1 diameter, blende 2.1 diameter.
3.0
=
4.0—1=3
2.6—I
1.6
""
3.0
1.6
1.88, or blende I diameter, quartz 1.9 diameter.
The theoretical reasons for sizing stuff before submitting it to the enrich-
ing machinery may be given in the following terms. If bodies of various
forms, sizes, and densities be permitted to fall in water in a state of rest,
they will experience a different amount of resistance, and consequently not
arrive at the bottom at the same time. The resistance which a body ex-
periences in moving through a liquid does not depend on its specific gravity,
but solely on its form and extent of surface which it presents to that
medium. Supposing we have bodies of the same size and form, differing
only in specific gravity, they will all experience the same resistance or lose
the same amount of moving force, this loss being proportionately greater on
lighter bodies than on those of a higher specific gravity, consequently the
latter will arrive at the bottom first. If, on the other hand, we suppose that
the bodies differ only in size, it is evident that the larger pieces will arrive
at the bottom first, because the resistance is regulated by the squares of the
dimensions of the surfaces exposed, while the moving force is proportionate
to their cubes. Hence it will be seen that the particles to be jigged should
be as nearly as possible of the same size, for the smaller surface of one grain
in proportion to its weight will, in a measure, compensate for the greater
density of another, and cause it to take up a position to which, by its
constitution, it is not entitled. The proportion between the maximum and
minimum sizes of the stuff to be operated on should be as the specific
gravity of the minerals contained in it.
TABLE SHOWING THE FALL OF SPHERES IN WATER IN ONE SECOND OF TIME, THE LENGTH OF
ALL BEING IN MILLIMETRES.
Diameter
Millimetres.
Gold.
Specific Gravity
Galena.
Blende.
Specific Gravity Specific Gravity
Quartz.
Specific Gravity
19'2.
Millimetres.
7'5.
Millimetres.
4'0.
Millimetres.
2.6.
Millimetres.
17.43
2614
1570
1066
*80
11.32
2197
1320
898
653
8.71
1849
IIIO
750
550
6.16
1569
935
624
461
4.36
1307
785
514
385
3:08
1097
660
448
326
2.17
340
555
378
275
1.54
780
465
317
231
1·08
653
393
266
194
*77
548
327
210
163
*54
456
275
188
137
Let it be supposed that it is necessary to know the relative velocities of
fall in water of grains of gold, galena, blende, and quartz, each 108 milli-
metre diameter. An inspection of the table shows the fall of gold to be 653
CHAP. IV.]
THE PRINCIPLES OF SIZING ORES.
707
millimetres per second; galena, 393; blende, 266; quartz, 194. Then let it
be assumed that the diameter of the grains vary, the foregoing table will
show that gold of 6 millimetres would settle at bottom at the same instant
as grains of galena 17·4 millimetres diameter, and that grains of galena
3 millimetres diameter would fall at about the same velocity as grains of
quartz 113 millimetres diameter.
10
If, further, it be supposed that the grains varied between 8.71 and 17'4
millimetres diameter, some time would elapse, after gold of 8.71 millimetres
had settled, before the galena would deposit itself. With blende, however,
of 8.71 millimetres, and quartz of 17:43 millimetres diameter, the grains of
both would appear at the bottom almost at the same instant.
TABLE SHOWING THE FALL OF SPHERES OF VARIOUS DIAMETERS IN LINES DURING AN EQUAL
UNIT OF TIME, THE DEPTH BEING IN INCHES.
Gold.
Galena.
Blende.
Diameter
Quartz.
in Lines.
Specific Gravity Specific Gravity Specific Gravity Specific Gravity
Coal.
Specific Gravity
19'2.
7'5.
4'0.
2'6.
1'4.
Inches.
Inches.
Inches.
Inches.
Inches.
8
100
60.003
40.825
29.814
12.910
5.657
84.090
50'532
34'329
25.071
10.856
4
70.711
42.492
28.868
21.082
9.129
2.828
59.460
35.731
24.275
17.728
7.676
2
50
30.046
20'412
14'907
6'455
I'414
42'045
25.266
17.165
12.535
5'428
I
35°355
21.246
14'434
10'541
4.564
0.707
29.730
17.866
12.137
8.864
3·838
0.5
25
15.023
10'206
7'454
3.227
0'354
21'022
12.633
8.582
6.268
2.714
0.25
17:678
10.623
7.217
5.270
2.282
0.177
14.865
8.933
0069
4'432
I'919
0.135
12.500
7.512
5'103
3.727
1.614
Were a sieve, partly charged with grains of different minerals, plunged
down say 20 or 30 feet in water, the various grains would arrange them-
selves according to their several velocities of fall, one over the other,
assuming them to be of uniform size. Supposing the grains to vary in size,
while a sphere of gold eight lines in diameter is falling 100 inches, the grains
of galena of the same size will fall 60 inches, blende 40·8 inches, and quartz
29.8 inches. But while the sphere of gold eight lines in diameter is falling
100 inches, one of two lines in diameter will fall only 50 inches, or half as
fast as the sphere of the same substance with four times the diameter.
Further, a sphere of gold 0.707 lines in diameter will fall about as fast as
one of quartz with a diameter of eight lines, or one of galena two lines in
diameter, and so on. It thus becomes evident that the velocity of fall of
substances in water depends not only upon their specific gravity, but upon
their bulk and gravity combined, and that, for a perfect separation of sub-
stances according to their gravity, it is essential that the particles should
either be of the same size, or that the variation must be confined within
certain well-defined limits. As a rule, therefore, the proportion between the
maximum and minimum sizes of the stuff to be operated on should be as
the specific gravity of the one to the other, the equivalent of water for the
sphere being deducted in each case from its specific weight thus :-
Gold and Galena
Galena and Blende
Blende and Quartz
6.5 •18
I
2.769
3.0
6.5
I
2.167
1.6
.3
I
1.88
Ꮓ Ꮓ
708
[BOOK III.
PRACTICAL MINING.
But to allow for irregularities in practice the proportion of the size of
trommel-holes 1: √2 may be taken.
TABLE SHOWING THE TIME REQUIRED FOR THE FALL OF STAMPED STUFF OF DIFFERENT
MINERALS AND OF DIFFERENT DIAMETERS.
Size of Stuff
in
Millimetres.
Galena.
Gravity
7'56.
Pyrites.
Gravity
Barytes.
Gravity
4'60 to 5'00.
4'50.
Blende.
Gravity
4'15.
Quartz.
Gravity
2'70.
From. To.
Seconds.
Seconds.
Seconds.
Seconds.}
Seconds.
Carbonate
of Lime.
Gravity 2'60.
Seconds.
30'00 18.00
0'90
2.36
18.00 7:00
I'II
3.67
7:00
5.50
I'50
4.61
5.50
4'44
1.84
6.10
4:44 4'17
2.03
2.54
2.81
2.88
7.27
3.86
3'94
3.67
2.48
3'43
3.73
4·61
7.61
5.56
2.77 2.50
3.11
4:41
5:55
6.53
6.83
I'77
1.50
4.14
6.21
8.30
9.78
10*17
I'00
5.27
10.36
11.33
11.67
14.64
17.21
Classifying Minerals.-The coarser portions of sand may be sized by
means of trommel, but usually for finer sand and slimes a different descrip-
tion of apparatus is employed. In this instance a classification of the
equivalents is first effected, and afterwards the ore grains are concentrated
together. The following are the principles affecting the classification by
the means to be described.
In an horizontal current of decreasing velocity, the larger equivalents
introduced will be deposited first, diminishing in size in an equal ratio with
the lessening velocity, till, with but a very slight flow, even the finest
slimes will be deposited.
A stream rising vertically with decreasing velocity carries the smallest
equivalents first away, and only the larger ones remain, while, in proportion
to the diminishing velocity of the stream, the finer and finest particles will
eventually be deposited.
Horizontal Classifier.-For classification of the equivalents according to
the first principle, launders with progressively increasing sections might be
employed, in which, first, the largest, and, in the last, the smallest equivalents
would be deposited and collected, but for the further treatment the influx
would have to be suspended while the various divisions were being com-
pleted. To obviate this the launders should be constructed with inclined
sides, and provided with a small opening at the bottom to allow of the efflux
of the classified stuff.
In the construction of the horizontal classifiers the following rules should
be adhered to :—
The width of the first division should be one-tenth of a foot for each
cubic foot of slime water introduced per minute, and the following divisions
should increase in geometrical progression, thus: 1, 2, 4, &c. The length
of the first division is usually taken at 6 feet, and increased in arithmetical
proportion, thus: 6, 9, 12, &c. The inclination of the sides should be 50°.
The Vertical Classifier.-The following is the adaptation of the second
principle:-
The slime water is conducted into the upper portion of a tank, which is
subdivided into three, four, or five divisions, so that an alternate ascending
CHAP. IV.]
DIVISION OF STUFF FOR DRESSING.
709
and descending current is caused. The velocity of this current is diminished
by increasing the area of each succeeding division, and according to the
principle the larger equivalents are deposited according to the number of
subdivisions.
Division of Stuff for Dressing Purposes.-Rittinger adopts one millimetre
in diameter as the unit of holes for sizing ores for concentration, and the
progression beyond this is geometric, as 1, 2, 4, 8, 16 millimetres, giving for
the volumes of the grains that will pass the holes respectively 1, 8, 64, 512,
4,096 cubic millimetres. He divides each of these sizes into four classes,
each with four grades, thus :—
fine.
Diameter in
Millimetres.
In Inches
nearly.
64.0
2.51
coarse.
No. 1. Rough Stuff
45.2
1.79
•
32.0
I.26
middling coarse.
fine.
""
22.6
0.89
fine.
16.0
0'64
coarse.
No. 2. Coarse Stuff
II
11.3
0'45
middling coarse.
8.0
0.319
5.6
O'220 fine.
No. 3. Coarse Sand
•
4221
4.0
2.8
2.0
fine.
""
1'4
I'00
No. 4. Fine Sand and Slime
0.71
0.50
\ 0.35
0'0200
0.160 coarse.
0'109 middling coarse.
0·078
0.055 fine.
0'0400 coarse.
0.0282 middling coarse.
0.0137 fine.
""
fine.
The divisions adopted by Darlington for the purpose of dressing lead and
copper ores are of a more simple kind. He reduces the stuff by means of
crushing-rolls to sizes varying from o to 7 millimetres. These are sub-
divided into-
No. I.
{ Rough Stuff
""
No. 2. { Coarse Sand
No. 3.1
"
( Fine Sand
""
Coarse Slime
No. 4. {Fine
""
•·
•
Mil.
Mil.
5 to 7 Sized for rough jigger.
3 /1/10
""
5
2 1
工
​32
I
""
"
""
☺ ☺
""
HA
""
""
""
coarse jigger.
1 Classified for fine jigger.
buddles or frames.
H* -D
""
""
""
For tin-dressing Darlington suggests the following classifying arrange-
ment :-
1. Place in front of the stamps a properly-constructed classifier, either an horizontal gradually widening
launder (Spitzkasten) or a series of V-shaped boxes, each proportioned in its dimensions to the
work to be done.
2. Treat each classified product directly in jiggers or upon round buddles or frames.
Metric System.-The metric system is now mostly in use throughout
Europe. In referring this system to the dressing of ores the metre for space
unit is used as the standard of velocities, while for the unit of time the
second is employed. As the metric scale of measurement admits of a closer
expression of the relative size of one grain of sand with that of another
than the ordinary division of the inch, the word "millimetre" will frequently
occur. An inch is represented by about 25 French millimetres or by 12
Prussian or Austrian "lines."
Z Z 2
710
[BOOK III.
PRACTICAL MINING.
The length of a metre is 39'3708 English inches, and is divided into-
I Metre (m.)
I Decimetre
metre or I or 39.3708 inches
I
O'I
Ο ΟΙ
100
""
I Centimetre (cm.) — o'or
I Millimetre (mm.) = 0·001
3'93708
or 4 inches nearly
0*393708 inch ,, or inch nearly
1000,, 0.0393708 ,, Tʊ or inch nearly
""
Axioms of Dressing.—(1.) Absolute perfection in separation according to
specific gravity cannot be arrived at chiefly on account of the irregularity of
form of the various grains to be operated upon.
(2.) The more finely divided the stuff to be treated, the greater the
amount of labour and care does the stuff require, and the more imperfect is
the separation.
(3.) That reducing machine may be considered the most perfect which
produces the least quantity of smaller stuff than the size intended to be
produced.
(4.) The value of limiting the degree of fineness to which a mineral
should be reduced at first, is that a proportion at least of the deads, as also a
portion of clean ore, will be obtained by the first operation of jigging, thus
saving valueless application of labour and power in the reduction of the
former, and preventing loss on a more minute subdivision of the latter. In
the case, therefore, of grains of ore of considerable size being contained in
the mineral to be treated, a waste, which would infallibly occur in the treat-
ment of them after a finer division of the same, is avoided, while, should
the proportion of matrix preponderate, a considerable quantity of waste is at
once withdrawn from the labour and expense consequent on its reduction.
As a general rule, therefore, the mineral to be treated should at first only
be reduced to that size which will allow of the separation of a portion of
the ore contained, or of the deads, should these be in a large proportion.
To what extent the finer reduction of the resulting middles or mixed ore
and matrix should be carried is dependent on the same principle as that
already given for the reduction of the mineral stuff, as also on the difference
between the specific gravity of the ore and the various other components of
the mineral substance.
As regards the separation of the reduced mineral, the following may be
assumed :-
(1.) That apparatus or plan of dressing may be considered as most
efficient which, with stuff of a given average size, allows with equal cost of
a more perfect separation of stuff of a nearer equal specific gravity. For,
the average percentage to which the crop is to be brought, and the highest
percentage to be allowed in the castaways being determined, it is evident
that the more perfect the degree of separation, the greater will be the amount
of crop and castaways obtained at each operation, and the quantity of
middles or stuff to be re-worked will be diminished. Thus, in the same
manner as was remarked in the observations on reduction, useless expense
and loss of ore will be avoided.
(2.) We may further consider, as a great improvement in dressing opera-
tions, such apparatus or plan of working which will allow, without a dispro-
portionate increase in the cost, of the equally perfect separation of fine stuff,
as that of the coarser, as now practised. This will be of especial benefit in
CHAP. IV.]
DRESSING MACHINERY AND APPARATUS.
711
the case of finely disseminated ore, which is obliged to be reduced to a great
degree of fineness.
Moisture in Ores.-The amount of moisture in ores sampled for sale
within the ordinary period after completing the dressing operation varies
with the constituents and size of the particles of which the pile of ore is
composed.
Lead Ore.-The following figures are derived from a series of average
results:
Cwm Erfin, per 21 cwts. 76 lbs. of water = 3.2 per cent.
East Daren
""
64
""
Goginan
102
""
= 2.7
=4.3
""
""
Lisburne
""
64
= 2.7
""
Cwm-ystwyth,
54
2.2
""
"
Minera
28
Average per 21 cwts.
64
= 1.25
3.69
Blende.
Minera
68 lbs. of water 3'00 per cent.
Oxide of Tin. Wheal Agar per 20 cwts.
Wheal Basset
130
158
=5·80
""
"
=7
The weight of a cubic foot of dressed lead ore will vary-(1) with the
quality of the ore, whether it may be solid or spongy in its structure;
(2) if free from earthy matter; (3) if the grains may be coarse or fine, or
much charged with moisture. Some varieties of fine grain silver lead ore
cannot be advantageously enriched to afford more than 50 to 55 per cent. of
lead, while heavy, pure, and compact galena may be dressed to yield 73 to
76 per cent. of metal.
TABLE SHOWING NUMBER OF CUBIC FEET IN A TON OF DIFFERENT VARIETIES OF ORE.
Galena.
Mines.
Esgair-hir-dressed ore
Minera
Ballacorkish
""
•
Wildberg-cobbed, dressed ore
sieve raggings
Hiendelaenncina-silver ore
Silver Ore.
Blende.
Minera
•
Oxide of Tin. Wheal Agar
•
Wheal Basset
་
Cubic Feet
Assay.
to a Ton of Oro.
73 per cent. of metal.
9
75
87%
""
70
ΙΟ
52
10
""
50
II
""
10
14 to 15
70
""
70
"
91%
91%
•
DRESSING MACHINERY AND APPARATUS.
The machinery and apparatus employed in the mechanical concentration
of ores may be grouped under the following heads :-
(A.) Dressing Tools.-Shovels, Hammers, Barrows, Trays, and Forwarding Apparatus.
(B.) Washing Apparatus.-Kilns and Washing Trommels.
(c.) Reducing Tools and Machinery.-Slides, Ragging Spalling, Stone-breakers,
Crushing Mills, Stamps, and Pulverisers.
(D.) Sizing Apparatus.-Riddles and Trommels.
(E.) Classifying Apparatus.-Classifying Troughs and Cones.
(F.) Jigging Machines.-Sieve, Lever, and Continuous Jiggers.
(G.) Buddles and Tables.-Strips, Round and Concave, Buddles, and Frames.
(H.) Calciners.-Brunton's and Hocking's Calciner.
(J.) Humid Processes.-Longmaid Duclos, Oxland, Henderson, Claudet.
(K.) Magnetic Separators.-King's Machines.
(L.) Tossing and Packing.
(M.) Sampling Ores.-Lead, Copper, and Tin.
(N.) Dressing Ores.-Lead, Copper, and Tin.
(A.) The dressing tools and appliances used are but few in number. As
they differ in some respects from the mining tools described on page 654, a
712
[BOOK III.
PRACTICAL MINING."
1
short description is required. The shovel, of a triangular shape, is made of
good hammered iron pointed with steel. The dimensions of shovels vary, but
one of an average size is about 11 inches wide at the top and 13 inches from
the point to the shank, weight 4 lbs., cost one shilling, to which must be added
fivepence for the handle. The handle should be of best cleft ash, free from
knots and slightly curved. A vanning shovel is 14 inches long and 13 inches
wide at the top. It has a finely-graded hollow for the purpose of retaining
the vanned ore.
Mallets are made of cast steel or rolled bar-iron. If of the
latter material, the eye must be punched across the grain. Many forms of
different weights are in use. Picks are of various dimensions and weights.
The Cornish "Poll" pick weighs 4 lbs. The head, which is 17 inches
43
long, is fitted with a handle 26 inches long. The sledge used for breaking or
“ragging” rocks weighs from 6 to 8 lbs., while the spalling hammer, made
of cast steel set upon a thin pliant handle, weighs only 1 lb. Picking boxes,
for collecting prill or dredge ore, are made of deal plank 1 inch thick. The
ordinary dimensions of a box are-length, 16 inches; depth, 7 inches; width
at bottom, 7 inches, and at top, 10 inches. Ledges of wood to serve as
handles are frequently nailed to the ends of the box. Wheel-barrow.-The
sides, ends, and bottom are made of deal plank 14 inch thick. The ends
are morticed to the sides, and the bottom fastened by means of nails. The
upper edges of the sides and ends are protected by strips of hoop-iron, while
short pieces of hoop-iron are used for strengthening the corners. The wheel,
frequently made of wrought iron inch round, is 14 inches diameter.
The length of the sides of an ordinary barrow is 60 inches, depth at centre
9 inches. Hand-barrow.-At surface, particularly for weighing and shifting
ore, a hand-barrow is generally employed. This barrow is provided with
handles at each end. The plank of which it is made is 1 inch thick; length
of sides, 66 inches; depth at centre, 9 inches; width at top, 18 inches; at
bottom, 10 inches; length at top, 24 inches; at bottom, 18 inches. Tram-
ways.—The gauge of surface tramways varies from 15 to 30 inches. Ordinary
bridge rails are usually employed; but where iron is dear and timber cheap,
a serviceable rail may be formed of a runner, a strip of timber 2 inches
square, and a strip of iron 1 by inch thick, laid upon the latter, and
fastened with nails or screws. Tram-waggon.-The tram-waggon is generally
constructed of sheet iron with wrought-iron axles and light steel wheels.
The capacity of a waggon is mostly an arbitrary one. Dipper-wheel.-
Stamped ore, and water heavily charged with slime, are commonly lifted
from a lower to a higher elevation by a dipper-wheel. This apparatus
consists of a wheel 15 or 20 feet diameter, with a wooden rim, to which are
attached sheet-iron buckets. These buckets, in their rotative movement,
scoop up, lift, and empty, stamped or slime ore to the height required. Stuff
consisting of slimes and sand may also be readily lifted from one point to
another by means of a raff-wheel, Jacob's ladder, or Archimedean screw.
Circulating pump.-Few mines of importance in the central part of Cornwall
possess an initial volume of water sufficient for dressing purposes.
To
overcome this drawback a circulating pump is employed. In most cases it
consists of a simple plunger attached to an engine. At Wheal Basset the
circulating pump in connection with eighty heads of stamps and adjacent
CHAP. IV.]
WASHING OF VEIN STUFF.
713
dressing appliances is 15 inches diameter and 9 feet stroke. This plunger
forces about 800 gallons of water per minute to a height of 60 feet, requiring
about 14 horse-power to do the work.
(B.) Washing Apparatus.-The vein stuff, on arriving at the surface, is
not only often associated with a large amount of gangue, but is frequently
much intermixed with clay, rock, and silicious matter.
In order to get rid of the latter substances it is usually washed and
picked. The washing apparatus ought to be so contrived as to allow the
cleansing to be effected both cheaply and expeditiously, and for this purpose
an ample volume and fall of water is always desirable. In accordance with
the character of the ore the apparatus will have to be varied; but for lead,
certain varieties of copper ore, as well as for iron or other abundant ores, the
wash-kiln will be found satisfactory. In many mines a rectangular grate is
fitted to the bottom of the kiln; but a perforated plate would be found to
furnish better results, since the former allows of the passage of flat irregular
pieces of stone, rendering their treatment in the jigging sieves less successful.
The holes in the perforated plate should be conical, the largest diameter
underneath, so that the stones may have a clearance-way. In connection with
the kiln-plate a sizing trommel should be used, and in order to economise
both time and expenditure it would be judicious to introduce the vein stuff
and discharge the castaways by means of railways.
The picking of the stuff is an important operation. As a rule all
picked ore should be selected, and the dredge deprived of the largest
possible amount of waste before it is sent to the crusher. It is fallacious to
suppose, because machinery will deal with large quantities of stuff expe-
ditiously, that it will be cheaper to subject the mass to its action; on the
contrary, if correct calculations are made of the losses ensuing on the initial
quantity of ore before the residue is ready for the pile, the cost of the several
intricate manipulations requisite to get rid of the castaways, and of the wear
and maintenance of machinery, it will appear in the greater number of cases
that the more profitable method will be to incur an extra first charge in order
to reject the sterile portion by means of hand labour. The ragging-hammer
should therefore be brought into free requisition, and all worthless stones at
once rejected; then in spalling such portions as have been ragged, an
additional quantity of refuse should be excluded, whilst in the process of
cobbing either ragged or spalled work, the greatest care and attention
should be given in order to bring the dredge to a maximum degree of
richness.
Wash Kiln.-In the lead mines of the North of England and Wales the
vein stuff as it comes from the mines is usually deposited in a receptacle
known as the kiln. This apparatus usually consists of a hopper-constructed
of wood or masonry-an opening at the bottom, a grate or perforated plate,
and a collecting-box set underneath the plate. Also of a water launder
placed above the kiln. The stuff deposited in the kiln is subject to the action
of a stream of water falling from the launder and of a rake used by a kiln-
man, who stands immediately in front of the grate. The effect of the grating
operation is, therefore, to free the stuff from clay, and to separate the former
into two classes.
714
[BOOK III.
PRACTICAL MINING.
(1) Roughs.--Stuff too large to
pass through the holes of the grate
and to be picked into.
(2) Smalls.—Stuff passed through
holes in the grate and to be jigged so
as to afford
|
(a) Prill, or clean ore.
(6) Dredge ore for cobbing.
(c) Waste for hillock.
(a) Clean ore.
(6) Raggings (dredge work) to be
reduced in crusher, and subsequently
jigged.
(c) Waste for hillock.
With this cheap and simple apparatus, usually the first stage in copper
or lead ore dressing, satisfactory results are obtained. In a single kiln
twenty tons of stuff may be grated in a day of ten hours, at a cost of less than
4d. per ton.
The following are actual results of kiln-washing:
Capacity of kiln, 20 tons.
Time required to grate 20 tons, one man, 10 hours.
Kiln-man
Throwing roughs "on picking-table," one boy
Delivering "fine stuff" to jiggers, one boy
5/6
=31d. per ton.
20
s. d.
2
6 per day.
I
6
I
6
5 6
Washing Kiln and Sizing Trommel.-Fig. 192 represents an elevation of
Fig. 192.
this arrangement introduced some years ago at the Frongoch mine, Cardigan-
shire. The kiln is a semi-elliptic structure of masonry, with an inclined bed,
at the foot of which is set an inclined grate; a launder supplies water for
washing purposes, while a man with a rake grates and distributes the
roughs to girls who stand around the tables. In this operation the stuff is
picked into
Prill, or clean ore.
Dredge ore to be "cobbed" or crushed.
Waste for the hillock.
The rough smalls, which have passed through the grate, now go to the
trommel, where it is further divided into
CHAP. IV.]
THE WASHING AND SIZING TROMMEL.
715
Rough smalls for the rotating picking-table, which are picked or sub-
divided by the girls into prill, dredge, and waste, and Fine smalls for the
jigging-sieves.
The dimensions of the kiln are-
Width at top from grate to back
Top length at back wall
Length at back of grate
Depth at back wall
Depth at grate
•
•
9 feet o inches.
12
4
I
""
O
""
6
4 "
6
77
The front wall of the kiln is 2 feet thick. The grate, 3 feet long, fixed
on timber, 5 inches by 6 inches and 5 feet long. This grate is cast with
bars 1 inch thick at top and inch thick at bottom. The open space between
the bars on the upper side is inch, and on the under side 1g inch; the
picking-table partly surrounding the grate is 63 feet long, 8 feet wide, and is
set 2 feet from the ground; the dividing trommel is 5 feet long, and I foot
5 inches diameter. It has a fall of 4 inches in this length, and is speeded at
40 revolutions per minute. The rotatory picking-table, 10 feet diameter and
22 inches high from the ground, makes every four minutes one revolution, or
a circumferential speed of 7 feet per minute. The hands usually required in
connection with this apparatus are—a man to grate and distribute the stuff;
four girls, two on each side of the table, to pick the stuff; and four small girls
at the rotating table. Men or strong boys are employed to remove the waste
to the hillock, the quantity of waste varying with the proportion which may
be associated with the stuff delivered to the kiln.
Washing or Clearing Trommel.-The washing or clearing trommel is
employed in many places instead of a washing kiln. Its use depends upon
the existence of large quantities of argillaceous vein stuff necessitating cheap
and rapid despatch; thus the clearing trommel is frequently adopted for
enriching iron and zinc ores, phosphate of lime, and minerals of low value.
The cylinder is commonly parallel with the axis. In some instances, how-
ever, it takes the form of a double cone, the larger diameter of one end being
united to that of the other. When the shell is strictly cylindrical in its form,
angle or T iron is fastened to the inside for the purpose of lifting and dropping
the stuff; but when conical, the stuff is either washed and delivered by an
Archimedean screw or by an arrangement of wrought-iron buckets similar
to those fitted to an ordinary raff-wheel. In cases where rock veinstone is
first rejected or reduced to a comparatively small size, the clearing trommel
may be furnished with one or more sizing cylinders, for the purpose of divid-
ing the stuff into fine and coarse sand for jiggers and rough work for the
picking table or crusher. Washing trommels may be constructed of wood
or iron; the latter is, however, the better material, except when acidulated
water prevails.
For the construction and working of wash trommels the following general
particulars are given :-Diameter of trommel, from 4 to 5 feet; length,
9 to 10 feet; angle of conical shell for ordinary vein stuff, 1 inch per foot;
for clayey stuff, inch per foot; number of revolutions per minute, 10 to 15;
water required, from 10 to 30 gallons per minute; quantity of ordinary
"small" vein stuff washed per hour, 6 to 10 tons; dirty clayey stuff, 3 to 5
tons: power required per trommel, from one-half to three-quarters of a horse.
716
[BOOK III.
PRACTICAL MINING.
(c.) Reducing Tools and Machinery.—In removing portions of a vein under-
ground, rocks are broken in which valuable ore is more or less dissemi-
nated. The vein stuff, enclosing oxide of tin, copper pyrites, or galena,
on arriving at surface is usually deposited in slides or receptacles formed
under an elevated tramway. At this point the large stones are ragged by
means of a sledge hammer, that is, roughly broken up and the sterile por-
tions rejected. The weight of a ragging hammer is about 12 lbs. If no
stone-breaker exists, the ragging operation is succeeded by a spalling pro-
cess, in which small hammers about 3 lbs. weight are used for reducing the
stones for the stamps or crushing mill to about the size of road metal. Since
the introduction of a stone-breaker the vein stuff is so effectually broken as
to materially diminish the crushing or stamping power which would other-
wise be necessary. When vein stuff is reduced to pieces by the spalling
hammer its compactness is not in the least affected, and being broken chiefly at
the "heads" or joints the stone retains its original texture. In fact, the only
effect of hand-spalling is to reduce the rock from large to moderately small
pieces. The stone-breaker, on the contrary, crushes up the rock irrespective
of joints or faces, and the toughness and texture of the rock is so destroyed
that the crushing-mill or stamps can act upon it with far greater effect.
Part of the extra efficiency of both mills is due to the fact that the stone,
when passing between the rolls or under the stamp heads, is broken very
much finer than is the case when hand labour alone is employed. There is
no danger of the work of the crusher or stamps being hindered by large
stones getting between the rolls or under the heads and impeding their
action for some considerable time before they are broken down; whilst, on
the other hand, the stamps working on an even bed will be uniformly doing
good work. Perhaps the best proof of the difference between the action of
the breaker on the rock and the action of the hammer is that the former will
produce three tons of fine sand where the latter will produce one. Thus the
stone-breaker not only does the actual breaking cheaper than it can be done
by hand labour, but at the same time it is doing part of the work which
would under other circumstances have to be done by the crusher or stamps.
When the crusher-mill is supplied from a breaker, the wear of the rolls or
heads is considerably lessened, and the feed may be rendered more regular.
The Stone-breaker.-The general cost of breaking a ton of tinstone by hand
and by means of machinery has been estimated by Captain Tregay, late of
Peden-andrea, particulars of which are as follows:
Cost of breaking tinstone.
Deduct for dividing do.
•
HAND LABOUR.
Per 100 Sacks,
equal 10 Tons.
£ s. d.
O
O I
6
43
Or per ton
STONE-BREAKER.
Cost of stone-breaker, 20 inches by 9 inches
Alteration of floors.
10) O 5 I
0 0 61%
L
400
300
700
S. d.
00
CHAP. IV.]
THE BLAKE STONE-BREAKER.
Interest on outlay at 5 per cent., assuming 50 tons put }
through breaker per day
Interest on £700 at 5 per cent.
Wear and tear
Coals and grease
Labour cost
Less dividing tinstone .
£ S. d.
Per 100 sacks,
equal 10 tons.
0 51
O
0 4
4
•
3 3/
1 3
0 2
201
717
Cost by hand labour
Do. by stone-breaker
In favour of stone-breaker
Or per ton
10) 0 3 12
0 0 31
6d. per ton of tinstone.
3 d.
""
22 d.
The question of the position of the stone-breaker on a mine is of consider-
able importance The chief object should be to render the dressing process one
of an automatic character. No definite rule can possibly be laid down as to
the position of the machine; that will in many cases depend on local con-
ditions. At Peden-andrea the stuff drawn to surface is (1) tipped into the tram-
waggon and pushed by the lander along a raised tramroad to a point over
the stone-breaker floor; (2) the stuff is then shot over a grating, the bars of
which are 2 to 21 inches apart, and the smalls separated from the larger
stones before reaching the floor below. Here the latter are picked over, and
any pieces too large to go to the stone-breaker are ragged. The breaker is
so placed that the stuff can be shovelled direct into the hopper. When the
stones are broken the fragments fall upon a lower floor beneath, where the
stuff is divided and sampled and thrown into waggons to be conveyed to
the stamps. The smalls not requiring to go through the breaker are wheeled
to a point over the lower floor, where they are sampled and thrown into
waggons below. This arrangement is rendered necessary from the fact that
the lode is mostly worked by tributers; hence as each tributer's stuff must
be divided and sampled, it is not practicable to allow the tin stuff to fall
direct from the stone-breaker into the tram waggons.
a "
In various Australian and American mines, the vein stuff is tipped upon
grizzley" or slide, the large stones go directly through the stone-breaker
and the small stuff through the grizzley bars. Both products then pass
together through a shoot set underneath the stone-breaker, into a hopper
communicating with the stamps.
If the jaws of a stone-breaker are set 2 to 2 inches apart at the
bottom, the stuff will be delivered from three to four times smaller than by
hand-spalling. The size at the opening at the top of the jaws varies with
and determines the size of the machine and measures the largest stone that
can possibly be dealt with. The weight of stone which can be reduced in a
given time necessarily depends upon its hardness as well as upon its struc-
ture, and obviously the result may be augmented or decreased according
to the distance between the jaws and the speed given to the eccentric shaft;
the best speed is from 200 to 250 revolutions per minute.
The following table gives the approximate weight of stone reduced by
jaws of various dimensions, also the power required, the eccentric shaft making
200 revolutions per minute :—
718
[BOOK III.
PRACTICAL MINING.
TABLE RELATING TO STONE-BREAKERS.
Stone-grinder
Do.
Do.
Do.
20 x
3
Do.
Do.
20 x 5
24 ×
6
Stone-breaker
H2
Do.
Do.
9 ×
IO X
Do.
12 X
8
Do.
I2 x
Do.
15 ×
8
Do.
15 × 10
Dimensions of Machine
at Mouth of Jaw.
Approximate Weight of
Stuff reduced.
Nominal Horse-
power required.
Inches.
5 ×
Cwt.
By Hand.
6 x I
12 X 3
Hmmmo to∞∞∞∞∞
5
2 to 4 Men.
ΙΟ
4
""
112
15
18
20
60
83
108
I 20
5
7
9
""
I ""
""
""
""
""
30
125
150
Do.
18 x 9
175
Do.
18 x 12
180
2335 SO N∞∞
""
""
""
8
""
Do.
20 X JO
200
8
""
Do.
24 × 13
280
ΙΟ
,,
Do.
24 x 15
300
12
""
Do.
24 × 17
330
14
Do.
24 × 19
350
16
Do.
30 x 13
350
16
""
Do.
30 × 15
370
16
"
Do.
30 x 18
400
18
Do.
24 × 24
400
18
Do.
30 x 24
460
20 ""
Both the movable and fixed jaw of a stone-breaker should be of double-
chilled iron. The use of soft or badly-hardened iron is highly objectionable,
since it will impose serious delays in withdrawing and replacing the pieces,
and increase the cost of reducing the stone. A pair of good jaws 12 inches
by 9 inches will cost about £3, to which must be added £1 10s., the cost of
taking out old and putting in new jaws, or a total of £4 10s. A bad pair of
jaws will not break 300 tons of stone, while a well-hardened pair will break
from 2,000 to 3,000 tons of silicious veinstone. In some dressing works sizing
trommels are placed under the stone-breaker, in others flat sizing sieves
are reciprocated by a rod attached to the movable jaw. The stuff is also
in some instances discharged on rotating or fixed tables, or on travelling
bands constructed on the principle of a coiling window shutter.
Fig. 193 shows sectional elevation of an ordinary stone-breaker as con-
structed by Marsden & Co., of Leeds. A, main frame; F, fly-wheel shaft,
which should make about 250 revolutions per minute by means of the belt
from the engine on to pulley, Q. The larger circle enclosing F shows the
eccentric. H, vertical rod connecting the eccentric with the toggle-plates J
and K, which have bearings forming an elbow or toggle-joint. These bear-
ings, it will be seen, are renewable, and the same may be said of all the
pillows and bearings throughout the machine. C is the cotter for taking up
the wear of the pillow or bush in which the eccentric works in the con-
necting-rod head; I is the cotter for keeping securely in their places the
bearings of the toggle-plates; B is a false back accurately planed on the
surface and bedded to the frame A; CI, 2, 3, and 4 are jaw-faces, which are
fitted with patent metal strips on their backs, and thus find a firm and even
bed for themselves, preventing sudden strains which they necessarily have

CHAP. IV.]
MARSDEN'S STONE-GRINDER.
719
to encounter, causing them to break and give way; E is the shaft of the
swing jaw which is cottered to it, and itself rests upon each side of the
main frame A; J is the key for keeping in position the swing-jaw faces C 3
and C4; D is the swing jaw itself; C 5 is a cheek of which there are two, one
on each side of the mouth, and which keep the fixed jaws in position, and
62
E
Fig. 193.
prevents the stone from wearing into the sides of the main frame; P is the
fly-wheel; L is the toggle-block and wedge. The toggle-block, as will be
seen, takes the cushion or bearing of the toggle-plate K, and itself is held in
position at one height always by means of lugs on each side of the frame;
whereas the wedge L moves up or down at the will of the user of the
machine, thus reducing or increasing the opening of the jaw at the bottom,
and so regulating the size of the product. The hook-bar underneath the
machine has an india-rubber disc attached to it at the end, which is
compressed by the forward movement of the jaw and aids its return; every
revolution of the eccentric F causes the lower end of the swing jaw D to
advance toward the fixed jaw about an inch and return; hence when a
stone is dropped in between the jaws it is broken by the next succeeding
bite. The fragments then fall lower down and are broken again, until
they are small enough to fall out at the bottom. The distance between the
jaws at the bottom limits the size of the product, and these distances, as
before named, can be regulated at will by turning the screw-nut which raises
or lowers the wedge L; greater variation may also be made by substituting
for the toggle J longer or shorter ones, furnished for that purpose.
Stone-grinder.-The ordinary stone-breaker has been modified in some
of its minor details by the Messrs. Marsden & Co. for the purpose of
reducing stone to the condition of sand. A, Fig. 194, is the main frame;
T, fly-wheel crank shaft, which should make about 300 revolutions per
minute by means of the belt from the engine on to driving pulley 2;

720
[BOOK III.
PRACTICAL MINING.
F is the connecting-rod which connects the crank with the lever c which
has its bearing on the fulcrum-shaft D; E is the shaft connecting the
end of the lever with the top of the grinding jaw B; G is the grinding-
jaw face, H is the fixed-jaw face, and each of these faces are fitted
with patent metal strips on their backs, thus enabling them to find a solid
bed, preventing the great strain they necessarily have to bear, causing them
J
B
N
R
A
to break; U is the
key, of which there
are two, one on each
side of the mouth,
which keeps the fixed
jaw-piece in position
and prevents the
material wearing
into the sides of the
main frame; N is a
wedge which, on
being lifted or
lowered by means of
a screw-key, thrusts
forward or allows to
recede the toggle-
block Mand grinding
Fig. 194.
jaw B, thus allowing
the jaws to be more or less open at the bottom according to the degree of
fineness the product is required to be, and also to take up wear on the jaw-
faces; W is the toggle or knuckle-joint plate which allows the grinding jaw
free movement, and at the same time keeps it within prescribed limits; R is
the bar connecting the spring to the grinding jaw, and which facilitates its
receding movement. It will be seen that, at the commencement of every
revolution till the centre is reached, the connecting-rod F draws up the end of
the lever C, which resting upon its fulcrum shaft D causes the grinding jaw
B, which is connected with the lever end by the shaft E, to have a forward
and downward grinding motion of immense power upon the material in the
mouth between the jaw faces G and H. The toggle-plate w also thrusting
forward the lower part of the jaw on the remaining portion of the revolution
the exact reverse takes place, and the material operated upon falls into the
shoot S, which conveys it into the sieve J. This sieve is fitted with gauze K
suitable for the fineness of product required; there are also supporting and
protective gauges fitted in every screen, which prevents injury to the finer
gauzes. By a raff-wheel arrangement in the interior, all material that will
not pass through the finer gauze is carried by the scoops L, and at each
revolution of the screen upon spindle I these scoops empty themselves into
the hopper o, which conveys their contents into the mouth in conjunction
with the regular feed to the machine; thus all the stuff gets ground and
reground upon until it becomes of the proper degree of fineness. The advan-
tage of this machine-which has been recently much improved-is, that by
a simple adjustment any degree of fineness can be secured.
CHAP. IV.]
CRUSHING AND GRINDING MACHINERY.
721
Crushing and Grinding Mills.-When copper, blende, or ore is freely
intermixed with veinstone the separation of one from the other is commonly
effected by crushing the stone, bringing particles of like sizes together, and
subjecting the products to the action of jigging-machines, or other suitable
enriching apparatus. Long experience has demonstrated the fact that the
difficulty of concentrating ore increases with its fineness, consequently it is of
great importance to secure the metalliferous grains as near to their natural
dimensions as is possible. Whatever practical care may be employed for
this purpose, the desired results can be only partially attained, nevertheless
a considerable loss in castaways, as well as unnecessary expense in dressing,
may sometimes be avoided by properly adjusting the pressure on the rolls,
and permitting the crushed stuff to go direct to a slime separator and sizing
trommels.
In Cornish mills the rolls, riddle, and raff-wheel arrangement produces a
kind of continuous crushing, the "roughs" larger than the riddle spaces
being again and again returned to the rolls. In soft copper and lead ore
associated with hard quartz and Slate, the result is an unnecessary pro-
portion of fine ore and clay, which in water too frequently forms a viscid and
objectionable slime. In Continental mills the raff-wheel and riddle seldom
form an accessory to the rolls. The general practice is to maintain the faces
of the latter in good condition, and to pass the crushed stuff direct to the
sizing trommels, sending only such portion as cannot be jigged either to
the first or to a second crusher. Except for the purpose of crushing earthy
varieties of coal, the German crusher is, for the same diameter, usually much
shorter on the face than those used in this country; in fact, the width of
the roll seems to be decreased in an arbitrary proportion with the hardness
of the stuff. In addition, the mill is provided with a fly-wheel for preventing
irregularity of motion. For crushing fine stuff a feed-roller is frequently
geared in connection with the crushing rolls, and the latter are always kept
to their work by means of adjustable springs. Disc springs, consisting of
alternate plates of india-rubber and iron, have altogether superseded the
lever and weight. Rolls subject to the former arrangement merely open
sufficiently wide to allow hard foreign substances to pass, but under dead-
weight pressure hard resisting material is apt to jerk the levers, and to carry
the rolls farther apart than is necessary; thus, with a long irregular line of
roller face uncrushed stuff must freely pass to the revolving riddle, be
raised and repassed until crushed sufficiently small to escape through the
meshes of the latter. The mode of gearing the roll to the axle is also
different in German to English practice. A thick cylinder is truly centred
on a wrought-iron shaft, and on the outer surface of this cylinder, which is
slightly taper, the crusher shell is securely fixed by means of three bolts and
nuts.
The rolls of French mills are from 8 to 45 inches in diameter, length
on face from 8 to 12 inches. In Germany the length of rolls for crushing
metalliferous ore is usually 10 inches long, which are from 10 to 36 inches
in diameter. For the purpose of crushing shaly coals the length varies
from 20 to 30 inches.
Now that the use of stone-breakers renders it unnecessary to employ rolls

722
[BOOK III.
PRACTICAL MINING.
of very large dimensions, coarse jigger work may be advantageously obtained
with rolls from 18 to 24 inches diameter, and fine jigger work from rolls
10 to 18 inches diameter.
Rough, coarse, and fine sand jigger stuff cannot be defined with any
approach to accuracy; either will naturally vary with the grain size of the
ore, and its associated mineral, which is determined principally by the
crystalline condition of the earthy and the metalliferous portions. It will be
sufficiently near for all practical purposes to regard stuff ranging in size
from 3 to 8 millimetres as rough jigger work, sand from 1 millimetre to
3 millimetres as coarse jigger work, and sand from th to 1 millimetre as
fine jigger work.
The cost of reducing a ton of stuff to a given size must depend on a
number of conditions, such as cost and hardness of rolls, charges incident to
wear and tear of machinery, cost of power, value of labour, structure of the
stuff to be crushed, and arrangement of the mill itself. Hard, well-propor-
tioned rolls should always be employed even if moderately economical results.
are to be obtained. In Germany steel rings have been found to give
excellent wear, but the cost of fixing and turning the rings has to a great
extent precluded their use. The circumferential speed of rolls in German
mills is from 90 to 180 feet per minute. Variable speeds have been tried in
order to produce friction, together with pressure at the line of contact; but it
has been found that any departure from a uniform speed in the two surfaces
Fig. 195.
absorbs a considerable amount
of power without materially
augmenting the results. Rol-
lers worked by friction furnish
less economical results than
those driven by spur gearing.
The following particulars
are given in connection with
a Cornish crusher operating
on steel grain lead ore, asso-
ciated with carbonate of iron,
quartz, and hard grauwacke:
-Diameter of rolls, 21 inches;
length on face of rolls, 19
inches; weight of new pair of
rolls, 2,700 lbs.; weight of
worn-out pair of rolls, 1,600
lbs.; number of revolutions
of rolls per minute, 8; speed
on face of rolls per minute,
42 feet; size of stuff before
entering rolls, 20 to 60 milli-
metres; size of stuff after
leaving rolls, o to 6 millimetres; weight crushed per hour, 2 tons; quantity
of stuff crushed by a pair of rolls, 2,000 tons; time required to take off and
to put on new rolls, 10 hours; number of hands required at the crusher, 3;

CHAP. IV.]
THE CORNISH CRUSHING-MILL.
723
cost of rolls, £18 3s.; labour changing rolls, including cost of iron wedges, &c.,
£1 7s. 6d. ; together, 19 10s. 6d.
Redemption of rolls, less allowance for old rolls
Labour cost
Steam-power (five horses).
Wear and tear of machinery, oil, &c.
Cost of crushing per ton of stuff
40000
00000
. d.
05
Ο Ι
2층
​0 0 9
Fig. 196 illustrates an ordinary Cornish crushing-mill in front and side
elevation. The front elevation, Fig. 195, shows the spur gearing driving
the rolls, the raff-wheel for lifting to the rolls the stuff crushed but too coarse
Fig. 196.
to pass through the meshes of the riddle, the inclined shoot for running the
stuff to the rolls to be re-crushed, the hopper for supplying the rolls, and a
shoot immediately under the rolls for delivering the crushed stuff to an
inclined riddle; while the side elevation, Fig. 196, show the ends of the two
rolls, the pressing pin and weight lever for keeping the rolls together, and
the circumferential line of the raff-wheel. The riddle under the rolls is not
shown, but this part of the apparatus divides the crushed stuff into two
sizes, viz. :-
Coarse or Roughs.-Returned to rolls by raff-wheel to be re-crushed.
Fine.-Sized and classified for jigging-machine and buddles.
The results of an experiment made for the purpose of determining the
sizes into which vein stuff was reduced by means of a pair of rolls is set out
in the following table. It will be observed that the proportions of stuff
3 A
724
[BOOK III.
PRACTICAL MINING.
from 7mm. to X to be re-crushed did not exceed 13 per cent., while the
proportion of stuff for the classifier varied from 30 to 48 per cent.
TABLE SHOWING SIZING RESULTS OF SAMPLES OF VEIN STUFF FROM CRUSHING MILL-(I)
PROPORTIONS OF STUFF RETURNABLE TO CRUSHING ROLLS; (2) SENT TO Jiggers; (3) Tỏ
BUDDLES Or Tables.
(1) For Raff-wheel to Rolls-
Stuff from X mm. to 10 mm.
73 mm. to 10 mm.
""
.",
(2) For Trommels—
Blende associated with Carbonate
of Lime, Quartz, and Galena.
No. I.
I'45
No. 2.
0.23
9'93
3.05
Galena with Car-
bonate of Lime
and Quartz.
Disposition
of Stuff.
No. 3.
3.23
9.46
To Crushing Rolls.
Stuff from 5 mm. to 7 mm.
12.20
7.91
11.95
To Jigger
No. I.
33 mm. to 5 mm.
15.35
10.09
17.76
Do.
No. 2.
""
""
2 mm. to 3 mm.
12.90
12.16
10'59
Do.
No. 3.
I mm. to 2 mm.
13.83
18.04
16.67
Do.
No. 4.
""
""
(3) For Classifier—
Stuff from I mm. to O
34°34
48.52
30°34
To Buddles.
100°
100°
100*
The following table affords particulars connected with the dimension and
speed of mills, results obtainable, and horse-power required :-
Metalliferous Ores and
Coal.
Mineral.
Diameter of Rolls
in Inches.
Length of Rolls
in Inches.
No. of Revolu-
tions of Rolls per
Minute.
Speed on Face of
Rolls per Minute
in Feet.
Quantity of
Mineral reduced
per Hour.
Horse-power
required.
36
ΙΟ
IO to 20
90 to 180
27
ΙΟ
12
20
80
,,
21
ΙΟ
""
15 20
,, 140
80 IIO
4
15
ΙΟ
25,, 30
""
""
80 IIO
12
IO
30
90
IO
IO
40
100
I
HA
5432 ==
5 tons
""
5 to 8
4 "" 5
3
", 4
""
""
227
21,, 31-
,, 3
I
""
2호
​(Hand Crushers.)
ΙΟ
ΙΟ
6 to 9
15 to
20
6
ΙΟ
50
3 to 4 men
2
,,3,,
36
36
27
•
27
2 2
21
21
223030
20
" 30
20
180
30 وو
,, 270
180
25,, 35
25,, 35
,, 270
170,, 240
170,, 240
212H
25
15
55
""
""
25
""
15
30,, 40
30,, 40
160
", 270
20
100
210
IO
434332
3/31/1
4 to 6
,, 5
4 "
6
,, 4
,, 4
""
""
,, 3
Stamping Machinery.-The stamping-mill is one of the oldest pulverising
machines known in connection with mining and metallurgic operations. In
its ordinary form it consists of a number of pestles, arranged so as to be
lifted mechanically, each pestle dropping into a coffer, the latter being so
comtrived as to admit of a continuous feed and discharge of the stuff. In
Agricola's "De re Metallica" illustrations are given (1) of stamps driven by
water-wheels with heads beating on a plain bottom; (2) heads falling in a
coffer-box, the water and stuff entering at one end and flowing away at the
other; (3) coffer-boxes set in front of each other, each fitted with an end
grate, the discharge of stuff being into one common launder; and (4) other
coffers, with front grates delivering sand to distributors, tables, and riffle-
CHAP. IV.]
STAMPING MACHINERY FOR ORES.
725
buddles. In the various examples referred to the batteries are formed of
three, four, and five heads. In Pryce's "Mineralogia Cornubiensis," A.D.
1778, a stamping-mill is illustrated, and a description given, from which the
following is taken :-
T
{
Seeing that a dresser's judgment is required in the choice of a grate, I
begin with the description of that first and necessary part of a stamping-mill
which is a thin plate of iron inch thick, 12 inches long, and to inches
wide. The middle of this, from 8 inches by 7 inches, is punched full of
holes, from the diameter of a small pin to that of a large reed; for the larger
the tin crystals inclosing the metal are so much the more capacious must be
the holes, and vice versa. This holed plate, commonly named the grate, is
nailed on the inside of the frame, near the bottom where the stamp-heads
pound the ore.
The lifters are three to each stamp, made of ash
timber, 6 inches by 7 inches square, and about 9 feet or 10 feet long. They
are armed at the bottom with large masses of iron, called stamp-heads, of
140 lbs. weight each or more; these are lifted up and let fall between two
upright parallel planks of oak timber by wooden knobs or teeth, called caps,
fixed in the barrel of the axletree at proper distances, and in number propor-
tioned to the circumference of the axis, which goes round by the power of
the water-wheel. Those caps in their round take up pieces of wood called
tongues, about 6 inches projecting from each lifter, which are fixed one in
every lifter at a proper place, so that each cap from the barrel of the axle
comes under the tongues and lifts them up one after another in a uniform
rotation. Each lifter, with its iron head falling upon the tin stuff, bruises it
down so small that it is all discharged through the little holes of the grate.
The hinder head lifts first, that falling forces the tin stuff under the second,
the second falling forces it to the third, that falling forces it on to the small
holes in the grate."
Before the end of the sixteenth century stamps were largely employed in
the mines of Germany, while from Carew it appears that they were used
in Cornwall, for the reduction of tinstone, in the time of Queen Elizabeth.
This writer describes the mill as made of "three and in some places sixe
great logges of timber bounde at the ends with iron, and lifted up and downe
by a wheele driven with water." In 1812 Woolf erected the first steam
stamping-mill at Wheal Vor, Cornwall, when the ratchet-wheel became a
necessary part of the driving axle. Subsequently at Lanescot, about 1830,
wrought-iron lifters and cast-iron angular guides were substituted for "ash
timber lifters and guides." In California, since 1850, cast-iron coffers have
been used along with movable anvils, dies, gib-tappets, steel cams, and
revolving heads; while in Australia the coffers are made of cast-iron or of
wood, the latter sometimes encased in iron, each kind of coffer being fitted
with a movable cast-iron bed. In Colorado a similar bed is in use, but in
Cornwall the bed is generally formed of capel or elvan and quartz beaten into
a working condition. In Germany a stone or concrete bottom is frequently
made by ramming into the coffer successive layers of quartz and stone; in
other cases a cast-iron plate is firmly wedged at the bottom of the box, the
interstices being closed by strips of wood. In some cases in Cornwall
"flashers" are substituted for grates. In Germany, Rittinger's "Stausatz"
3 A 2
726
[BOOK III.
PRACTICAL MINING.
and the Hungarian "Schubersatz" are both employed. In the absence of
water for driving stamping-mills steam power is usually resorted to.
The steam-engine invariably employed in Cornwall for driving the Cornish
stamps consists of a vertical cylinder, main beam, sweep-rod, heavy fly-wheels,
plug valve gear, double-beat valves, condenser, and air-pump. The steam is
admitted above and below the piston, and cut off by an expansion slide on
the plug rod at any desired point of the stroke. This kind of engine is
designated by the Cornish engineer "double-acting," in contradistinction to
the "single-acting" character of the Cornish pumping-engine, which admits
steam on one side of the piston only. The double-acting stamping-engine
also drives the cam-axle direct without the intervention of intermediate
gearing, the speed of the stamp-heads or number of drops per minute being
obtained by means of cams set in the axle, usually a five-fold multiple of the
stroke of the engine itself.
The friction, or loss of power in lifting the heads in a 36-inch cylinder
stamping-engine at Wheal Vor, was tested by Mr. Husband, of Hayle, who
remarked as follows: "The engine was in good working order, stroke in
cylinder 10 feet double acting, and driving 48 heads. We found the indi-
cated horse-power 50, and the actual work done, i.e. weight lifted, equal
30 horse-power. The axles, &c., were of the ordinary kind, with five cams
in the round, and average lift of heads 6 inches." The loss in running the
engine and stamping apparatus was, therefore, 20 horse-power, or 40 per
cent. of the indicated horse-power. This loss of power would appear to be
unusually great, but it is scarcely to be attributed to the engine or arrange-
ment of stamps; it must rather be ascribed to bad maintenance of the axles,
cams, tongues, and lifters.
The duty or useful effect of a steam-engine is the number of pounds lifted
I foot high by the consumption of a given weight of coal. As an example,
50 heads of stamps may be taken without reference to friction or nature of
accessory parts. Weight of head, 584 lbs., less the wear, to average the
weight of heads, say, one-third, or net 390 lbs. ; lifter and tongue, 275 lbs.
665 lbs.; number of blows per minute, 50; lift per head, 10 inches. Then
ΙΟ
12
50 × 665 × 50 X = 1,385,416 lbs. raised 1 foot per minute. Consumption.
of coal, 3,920 lbs. in 24 hours, or 100 lbs. of coal in 367 minutes. 1,385,416 lbs.
× 367 minutes, give a duty for the consumption of 100 lbs. of coal of
50,844,767 lbs. The horse-power required to lift the foot-pounds per minute
is found thus:
1,385,416
=419. Without knowing the construction of the
33,000
apparatus and incidental work it may have to perform, it is evident that the
duty cannot be strictly determined. It is also obvious that the result can
only be approximately correct, since the total weight of heads and amount of
friction will continually vary.
The number of heads in a coffer is in Cornwall four, occasionally six, as
at Wheal Uny; in Germany, three or four; and in America, from three to six,
but commonly five. The weight of lifter and head in Cornwall for tinstone
varies from 400 to 800 lbs., and in Germany for lead ore from 300 to 500 lbs.
In Australia, for reducing quartz, from 300 to 800 lbs., while in America it is
CHAP. IV.]
THE COST OF STAMPING ORES.
727
from 600 to 900 lbs. The lift of the head in Cornwall ranges from 8 inches
to 10 inches, generally 9 inches; in Germany, for lead ore, from 4 inches to
12 inches; in Australia, for gold quartz, from 5 to 12 inches; and in America,
for gold and silver ore, from 4 to 10 inches. The number of drops of the head
per minute differs rather with the locality than with the nature of the mineral
to be reduced. In Cornwall the number is from 50 to 70; in Germany, with
a low fall for skimpings, it is as high as 120; in Australia, from 40 to 80; in
California and Nevada, from 70 to 90. Occasionally in the quartz mills of
America 120 drops per minute are made, but the fall in such cases rarely
exceeds 5 or 6 inches.
The volume of water per head varies with the character of the stuff
stamped and the degree of fineness to which it is reduced. For Cornish tin-
stone the water used is approximately 3 gallons per head per minute; in
Australia, from 3 to 10 gallons per head per minute; while in Nevada it
ranges from 1,500 to 1,900 gallons per ton of quartz. In Germany it is
reckoned at from 3 to 5 gallons per head per minute. The consumption of
fuel is also more or less dependent on the quality of the coal, character and
condition of engine, and degree of fineness to which the stuff is to be reduced.
In Cornwall from 2 to 1 cwt. of coal is sufficient to reduce a ton of veinstone
to sizes of millimetre and downwards.
3
The cost of stamping is an item which must necessarily depend upon cost
of fuel, labour, and a variety of circumstances connected with the reduction
of the stone; but in Cornwall it is accomplished at from Is. 1od. to 2s.,
and in Victoria, Australia, from 2s. to 4s. per ton. The fineness to which
stone or quartz should be pulverised must depend on the disposition of the
ore or fineness of the precious metal associated with its matrix. If either of
these should consist of highly minute quantities, the stone must be reduced
proportionably fine; if, however, the ore or gold should be somewhat coarsely
aggregated with the matrix, then the degree of fineness to which the stone
should be reduced may be proportionately lessened. The grates or screens
used in stamping-mills are supposed to suit the character of the ore.
Cornwall the grate-hole for tinstone varies from 1 to 1 millimetre in
diameter. The grates are known by consecutive numbers 27 to 39. In
America the quartz is passed through fine holes, the size of which is regulated
by the sewing-machine needles numbered from zero to 10; No. 8 is and
No. 5 about inch diameter. In Australia for the reduction of gold quartz
the number of holes per square inch in the screen varies from 60 to 250.
16
I
In
The weight of quartz reduced in a given time is, more or less, consequent
on hardness of rock, weight of head, height of fall, rapidity of blows, and
number of grate. In California and Nevada the weight reduced is reckoned
at 2 tons per 24 hours, in Australia from 1 to 4 tons, and in Cornwall from
to 1 ton. In America the mills are mostly automatically fed, notably by
Hendy's feeder, while in Australia feed shoots as well as passes are employed.
In Cornwall passes inclined at a suitable angle are invariably used.
The order in which the heads lift and drop in a coffer depends entirely
upon the manner in which the engineer has set out the relative position of the
cams on the axle. In Cornwall, with four heads in a coffer, it runs 1, 4, 1, 2,
and 2, 1, 4, 3; in America, with five heads, the order is 5, 3, 1, 4, 2-1, 3, 5,
728
[BOOK III.
PRACTICAL MINING.
2, 4—3, 4, 2, 1, 5—2, 4, 5, 3, 1, or 3, 5, 1, 4, 2; in India the stamps are set to lift
and drop in the order of 1, 4, 2, 5, 3 ; while in Australia, the coffer usually
containing five heads, the order of rise and fall is sometimes 3, 5, 1, 4, 2.
Advantages afforded by Stamping Mill.—The following are among some of
the advantages afforded by the stamping-mill:-(1.) It gives a dead blow,
highly effective in reducing semi-elastic minerals. (2.) The force of the
blow can be readily modified by shifting the position of the tappet. (3.) The
free fall of the head is entirely exerted on the stuff, and its effect is in no
way transferred to the framework or other parts of the apparatus. (4.) The
repairs required are few and simple, such as an ordinary mine smith and
carpenter can execute. (5.) A single battery of heads may be stopped and
repaired while others are running. (6.) Single heads may be thrown out of
use without affecting the working conditions of the mill. (7.) The mineral
under treatment receives the least possible handling, and can be flumed at
once either to dressing or amalgamating apparatus. (8.) Minerals can be
readily reduced to a condition of fine sand provided the faces of the heads
are good. (9.) Speed, lift, weight, size, form of head, position of discharge,
and extent of grateway admit of numerous variations to suit the conditions
of different minerals, and afford a wide field for the exercise of intelligence,
judgment, and practical skill.
The power, and water, required for running a mill must necessarily be of
a variable character. In the Western States of America the object of the
miner and millman is to reduce the largest possible weight of quartz per
head, per day of 24 hours, and the whole tendency of their practice is to
increase the weight of the head, lessen the length of its drop, and augment
the number of drops per minute. The head and its accessories now weigh
from 750 to 900 lbs. In a 40-head stamp-mill, reducing 100 tons of quartz
per day of 24 hours, the following approximate figures apply :-
(1) Power-1 Stone-breaker, shaft making 175 revolutions per minute
8 Automatic feeders
•
40 Heads 750 lbs. each, making 90.8 inch drops per minute
10 Grinding and amalgamating pans, each 65 revolutions per
minute
8 Separators, each 8 revolutions per minute
I Agitator, making 50 revolutions per minute
4 Concentrators, each making 200 revolutions per minute
Friction, one-third or 33 per cent.
Total Horse-power
Horse-power.
5.0
2.0
54.5
•
72.0
16.6
3°0
8.0
•
53°5
•
214.0
(2) IVater-214 Horse-power
40 Heads
16 Grinding and amalgamating pans
8 Separators
Total water required
For boiler
""
each stamp head
""
""
5-feet pan
""
8-feet settler
د,
Or say,
Water required per Minute.
Pounds.
170 or
625
375 ""
Gallons.
17
""
62-13/0
37/
115
1285
I I
""
-K-A-N
128/1/
7 gallons per horse-power per hour
72
""
per hour.
120
""
60
""
""
CHAP. IV.]
CORNISH GRAVITATION STAMPS.
729
For the milling of gold and silver ores, the usual rate of the weight of
water to that of rock is as nine to two (9: 2) :—
Stamping
Grinding and amalgamating.
Separating or settling
Silver mill, including horse-power.
Water per Ton of Ore.
Cubic feet.
Gallons.
Pounds.
144
900
9,000
86.4
540
5,400
25.9
161.7
1,617
293.2
1832.5
18,325
In working the copper ores of Lake Superior, 20 cubic feet or 125 gallons
of water to I cubic foot of ore are used, or equivalent to 8 to 1 by weight.
In many mines in America valuable quantities of brittle sulphide of silver
are mechanically associated with the ores. At Butte, Montana, the ores
include the sulphides of silver, antimony, lead, and zinc, together with a
little copper ore and manganese.
The ores are stamped dry without the admission of water to the coffer,
hence the volume of water required for dry is much less than that necessary
for wet stamping. A ten-head dry stamping-mill will use-
For steam and general purposes, per minute
Four grinding and amalgamating pans, per minute
Two settlers, per minute
4 gallons
6/1/10
•
40 lbs.
""
65 "
2
20
""
""
12
or 125,,
The water used for stamps, pans, and settlers, after a loss of about 30 per
cent. of its weight, can be pumped and re-used in the machinery.
TYPES OF STAMPING APPARATUS.
Pulverising Character.
Type.
Class of Stamps.
(A.)
Gravitation stamps.
(B.)
Direct-acting steam stamps
(C.)
Crank and spring stamps
Pulverization effected by the weight of
head falling through a given height.
Pulverization effected by the weight of
head plussed by the expansive force of
the steam employed.
Pulverization effected by means of a
crank and spring, the blow being
intensified by the excess of move-
ment which may prevail over and
above that consequent on weight and
force of gravitation.
Cornish stamps.
Californian
"
Australian ""
Wilson's stamps.
Ball's stamp.
Husband's pneumatic
stamps.
Scholl's ditto.
Patterson's mechanical
spring ditto.
(A.) Cornish Gravitation Stamps. -In Cornwall the weight of tinstone
stamped per annum is estimated at 600,000 tons, requiring about 2,000 horse-
The average
power, or 300 tons of tinstone per horse-power per annum.
weight of a head without lifter is 4 cwts., with lifter 6 to 7 cwts. The
average life of a head is about 4 months, while the loss of chilled cast iron
in stamping a ton of stuff is about 3lbs. The weight of tinstone stamped per
24 hours varies from 15 to 20 cwts., which is more or less increased, by first
preparing the stone by means of a stone-breaker, to the extent of from 15 to 20
per cent., which will give respectively about 17 and 24 cwts. per 24 hours. The
730
[BOOK III.
PRACTICAL MINING.
..
lifters are usually made of flat wrought iron about 3 inches wide by 2 inches
thick, and the head of hard chilled cast iron about 22 inches long by 11 inches
wide and 7 inches thick. The average lift is about 9 inches, the maximum 10,
and minimum lift 7 inches. The tongues on the lifters are made of wrought
iron steeled, and the cams on the axle of cast iron. The coffers are generally
made of wood, the grate-plates being of copper with a variable number of
holes per square inch. The size of the holes is of considerable importance,
and is determined according to the quality and degree of fineness of the
grains of oxide of tin in the stuff to be stamped. The stamps are arranged
in long rows, each axle lifting 16 heads, set in 4 coffers. In some mines
there are as many as 25 sets of coffers or 100 heads. One of the drawbacks
alleged to be consequent on slow stamping (50 to 70 drops per minute) is the
production of an unusual proportion of slime containing minute grains of
oxide of tin not directly obtainable by the ordinary method of dressing. At
West Wheal Peevor the grates employed are known as No. 36, answering to
No. 6 American needle. The holes on the inside or end of the "punched
burr" are about th of an inch in diameter. A sample of stuff stamped and
passed through the grate was sized, and afforded the following results :—
50
From th of an inch diameter to grains passing through wove
wire work, 6,000 holes per square inch
""
6,000 to 12,000 holes per square inch
""
12,000 to the fineness of zero per square inch
26.7 per cent.
13.2
60'I
""
100'0
It will thus appear that the greater portion of the stuff reduced was, in its
grain size, very much finer than the diameter of the hole in the grate through
which it passed. In this case, admixed with water, the fine slime may be
reckoned at 13.2 per cent., and the impalpable slime at 601 per cent. The
tinstone (tin stuff) is usually brought to the stamps, Fig. 199, in tram
waggons and tipped upon an inclined plane, known as the pass and half-
pass. The inclination of the pass is about 1 in 1 foot, and that of the
half-pass 1 in 24 feet. The half-pass leading down to the coffer mainly
regulates the speed at which the heads are fed. The exact amount, how-
ever, is, as it were, obtained by the continuous flow of a small stream of
water upon the stuff itself. This water goes into the coffer along with the
stuff when the stamps reduces the latter to a fine powder and "flashes" it
through the grates set in the front and ends of the coffer.
I
In a communication made by the late Mr. John Hocking, to the Mining
Institute of Cornwall, on the subject of a new 40-inch cylinder stamping-engine
erected at West Basset, he observed: "When the erection of the new engine
was determined on, we resolved that everything that was possible should be
done to economise fuel and to reduce the cost of dressing to a minimum
point. To economise fuel and to produce the best stamping results three
things were essential: (1.) The construction of an engine and buildings of
sufficient strength to allow of a high rate of expansion of steam. (2.) Boilers
of the best and most approved construction and strength to work high-
pressure steam, and of sufficient power and heating surfaces without forcing
the fires. (3.) Stamp heads and lifters of unusual weight, and for the
CHAP. IV.]
RESULTS OBTAINED FROM STAMPS.
731
dressing department a site by which the different dressing processes follow
each other by their own gravitation, and thus to avoid the cost of lifting the
ore back by hand labour and by artificial means." The main particulars
connected with the West Basset engine and stamps may be abbreviated as
follows: Stroke of engine 9 feet, double acting; number of heads attached to
engine, 4 axles of 16 heads each, or total 64; average number of revolutions
per minute, including stoppages, 107; load per square inch on piston, 9'31
lbs.; consumption of coals per week, 17 tons; duty of engine, 66ths
million of pounds lifted 1 foot high; quantity of tinstone stamped, 621 tons;
coal consumed for stamping one ton of tinstone, 613ths lbs. ; weight of tin-
stone stamped per head per day after allowing for stoppages, 34 cwts. ;
average weight of head and lifter, 877 lbs. Total load in foot pounds, 2 10,480.
The steam to the cylinder was admitted at a pressure of about 18 lbs. per
square inch and cut off at a little less thanth of the stroke; the boilers
were fitted with cone tubes, while the stamp lifters were of increased size and
length, viz. 3 inches wide, 2 inches thick, and 16 feet long. The cost of
keeping the stamps in repair, allowing for wear and tear, exclusive of grate-
plates and smith cost, was (1877) 31d. to 31d. per ton of tinstone stamped.
The quantity of water required for dressing purposes for 80 heads, reducing
70 tons of tinstone per 24 hours, was 800 gallons per minute, or roundly 400
gallons of water for every pound of black tin rendered fit for the smelting
furnace. The direct cost of stamping was—wear and tear of machinery and
apparatus, 3½d. per ton; coal, 61 lbs.; at 17s. per ton, 5d.; or together
9d. per ton. The various cost per ton of tinstone may be thus specifically
stated :-
Keeping stamps in repair
3
10
Direct cost of stamping, exclusive of interest on plant
3 d. per ton.
5 d.
""
9d.
""
Interest at 5 per cent. on cost of plant, reckoned at £4,000,
and life of plant at 14 years
2 d.
""
Total
Ι
Ild.
The following are some results connected with steam stamps formerly in
use at Polberro, St. Agnes, and Wheal Polrose, Breage, Cornwall.
Polberro.-Diameter of engine cylinder, 36 inches; actual horse-power
employed in stamping stuff, 55; number of tons of tinstone stamped during
1856, 31,411. This result was accomplished at the rate of 8 strokes per minute
in the engine, with an equal number of revolutions in the cam shaft, lifting
72 heads 9 inches high, each head weighing respectively 600 lbs. The
maximum number of blows made per minute was 50, the average number 45.
Two fly-wheels attached to the engine, each 30 feet diameter, weighed
34½ tons, and with crank shaft and bolts the weight of metal was 42 tons.
The total cost of stamping, including maintenance of engine, wear and tear
of machinery, wages of all kind, coal, oil, grease, hemp, &c., divided by the
tons stamped, amounted to Is. 3 d. per ton.
Each head stamped 436 tons per annum, or 28 cwts. per 24 hours, while
the whole number reduced 100 tons daily at a cost of 2s. 4d. per horse-power.
The stamp heads and accessories weighed collectively 191 tons, and as the
drop was 9 inches per head and 45 drops were made per minute, it follows

732
[BOOK III.
PRACTICAL MINING.
that a mass equal to 877 tons was lifted through a height of 33 feet in a
corresponding period. The screens were 72 in number. The dimensions of
וויוי
וויוון
Fig. 197.
Fig. 198.
grates to each coffer were-front screen 9 by 6 inches, two end screens, each
8 by 6 inches, number of holes in screen 140 per square inch (Figs. 197, 198).
CHAP. IV.] CALIFORNIAN AND AUSTRALIAN STAMPS.
733
Wheal Polrose.-The diameter of the steam cylinder was 30 inches;
length of stroke, 7 feet; number of heads attached to engine, 60; weight
of each head and lifter, 7 cwts. The stuff was partly stamped through
flashers and partly through screens, the latter were 11 inches by 9 inches,
punched with holes mm. diameter; the number of blows per minute per
head was, 55; and weight of stuff stamped per head per 24 hours, 25 to
28 cwts.
Californian and Australian Stamps.-The Californian and Australian
stamps differ in many respects from the Cornish stamps: (1) the heads
and lifters are round; (2) the tappets are lifted by means of cams deve-
loped to the form of an involute curve; (3) the heads partially rotate
during the lifting operation; (4) the coffers are of cast iron with heavy
cast-iron bottom; (5) movable shoes are attached to the heads; (6) mov-
able dies are placed at the bottom of the coffer; (7) grates are not placed in
the ends of the coffer; (8) the speed or number of drops per minute varies
from 70 to 120; (9) the foundations for the coffers are formed of heavy
blocks of timber; (10) five heads are invariably placed in a coffer. Figs. 197
and 198 illustrate stamps made by an eminent Cornish firm in which most
of the special details of a Californian stamps are introduced.
The illustrations (Figs. 199 and 200) represent front and end elevation
of eight heads of Cornish
stamps supposed to be
driven by a water-wheel
and spur gear. The stuff is
first lodged in the pass or
hopper, from whence it
gravitates to the half-pass
into the coffer, where it is
stamped. Each coffer is
provided with two front and
two end grates, and contains
four heads. The axle in
front of the lifters is fitted
with three tappets "on the
round," each single head
lifting three times during a
revolution. The shanks and
lifters are made of best
selected scrap iron, and
the heads, from 3 to 6 cwts.
each, are cast in chills from
a special mixture of hard
white iron. The lift of the
Fig. 199.
head is about 9 inches, and at 70 drops per minute the stamping capacity
may be reckoned to be 20 to 25 cwts. per head per 24 hours.
The illustrations show the woodwork, bed, log, and wall, or concrete
foundation.
(B.) Direct Acting Steam Stamps.-Various attempts have been made to
734
[BOOK III.
PRACTICAL MINING.
נון
MURAMEMNON:
UBURNUKON
AUREERIMUINA IMANDATANGANGINNA
The
apply steam direct to the lifting of stamp-heads. Wilson of Philadelphia,
Pennsylvania, contrived a battery consisting of two direct-acting steam
cylinders, and valves worked with tappets set on the stamp-lifters.
steam pressure, applied to cylinders 5g inches diameter and 7 inches long,
was 65 lbs. per square
inch. Ball of Lake Supe-
rior has also successfully
contrived a direct-acting
steam stamps for the re-
duction of amygdaloid and
conglomerate containing
native copper.
In the
largest machine yet con-
structed the weight of
head, lifter, and shoe is
about 2 tons, extreme
length of stroke 28 inches,
number of drops per
minute 90, horse-power
required 60, weight of stuff
reduced and passed per
24 hours, through grates
with holes inch dia-
meter, 110 tons. The
movement of the piston
is effected by a valve
worked by an indepen-
dent motor, one man being
Fig. 200.
المثلت امه
1
16
employed to look after the valves to two machines. To prevent the striking
of the cylinder covers stops are employed. At the Atlantic mill the steam
goes into the stamps cylinders at a pressure of 65 lbs. per square inch, the
exhaust steam runs into a receiver and heater 50 feet long and 2 feet in
diameter, the steam pipe from which goes to the main mill. The weight of
coal consumed to a ton of stamped rock is about 100 lbs. About 25 tons of
water are required to a ton of rock. A bed of stuff always lies on the coffer,
which prevents the head from coming in contact with the die. The "waste
of the head is said to be one pound of cast iron to four tons of stamped stuff.
(c.) Crank and Spring Stamps.—Fig. 201 represents Husband's pneumatic
stamps.
The stamp-head is not lifted direct, but is attached to a piston working in
an air-cylinder, and this cylinder has a reciprocating motion imparted to it
by a crank-shaft through a forked connecting-rod coupled to trunnions upon
the cylinder. When the cylinder is raised by the crank, the air below the
piston is compressed and the stamp is thrown up; and on the crank turning
the centre, the air above the piston is compressed and the stamp is driven
down with a velocity considerably greater than that due to its weight and
natural fall. The stamp-head and piston-rod, weighing together nearly
3 cwts., fall about 16 inches, with a stroke of 10 inches in the crank, and make

CHAP. IV.]
HUSBAND'S PNEUMATIC STAMPS.
735
from 120 to 150 blows per minute. A ring of small holes is made around
each cylinder immediately above and below the central position of the piston,
so that both ends of the cylinder
may be filled at each stroke with air.
A continuous stream of water flows
through the hollow piston-rod, for the
purpose of neutralising the heat de-
veloped by the rapid compression of
the air trapped within the cylinder.
This water is discharged through small
holes at the bottom of the piston-rod,
just above the stamp-head, and serves
as part of the supply of water for the
stamping operation. A considerable
portion of the water necessary for the
stamp-head is delivered in a circular
jet under several feet of head to the
outside of the piston-rods passing
through the coffer cover. In order to
prevent the unequal wear of the
stamp-heads, which would arise from
the supply of fresh uncrushed stone
to one side only, horns are employed
for turning the heads. About once
a day the position of the heads is
shifted, so as to cause the stamp-
head to wear in a fresh place. These
pneumatic stamps, hitherto mostly
erected in pairs, are said to reduce
from 8 to 10 tons of tinstone per head
per day.
In some stamps erected the total
weight of head and lifter was from
310 to 320, and it required about 12
Fig. 201.
indicated horse-power to drive a pair of
such heads at 150 blows per minute. The weight of coal required to stamp
the tin stuff at Carn Galver mine, where two heads were driven by a combined
engine, with 9 and 17 inches cylinder, 15 inches stroke, and 70 lbs. of steam
per square inch on piston, was about 1 cwt. to 1 ton of tinstone. At New
Rosewarne mine, Gwinnear, 196 tons of tin stuff were stamped with a con-
sumption of 156 cwts. of coal, or about 1 ton stamped per cwt. of coal. Less
slime was produced in these than in the ordinary stamps, from the circum-
stance that the contents in the coffer were kept in a continuous state of
agitation, driven quickly against the grates, and forced through the holes as
soon as it had come to the required size. The "wear" or loss of iron in the
stamp-heads was about 1 ton to 1,000 tons of reduced tinstone. This result
was partly attributed to the periodical turning and regular wear of the heads,
and to casting the head with a hole up the centre.
736
[BOOK III.
PRACTICAL MINING.
The cost of a set of stamps equal to 70 heads of ordinary Cornish stamps,
including a driving-engine, but excluding cost of boiler, is about £1,400. Less
water for stamping a given weight of stuff is required than in the Cornish
stamps.
At Tregembo mine, St. Hilary, Cornwall, two single-head oscillating
stamps are in use. The weight of each head is 9 cwts., horse-power required
per head 16, number of tons of tinstone stamped per day of 24 hours through
grate-holes 1 mm. diameter, or No. 32 Cornish gauge, 13 to 15 per head, fall
of head 14 to 15 inches, number of blows per minute 120. The loss of iron
per head to stamp a ton of stuff varies from 1 to 2 lbs. The total area of
the grates, which consist of punched copper-plates, is 10 square feet.
A sample of stuff, taken after it had passed through the grate-holes 1 mm.
diameter, was sized through three sieves with the following results :—
Size of grains which passed through grate-holes I mm. diameter, but would
not pass through a wire sieve 6,000 holes per square inch
Size of grains which passed through sieve 6,000 holes, but would not pass
through sieve 12,000 holes per square inch
Size of grains which passed through sieve 12,000 holes per square inch,
and which would form in water a gritless slime
•
54'0 per cent.
10.8
35°2
100'0
With these stamps the quick and lively blow keeps the water in agitation,
and the large grates allow the stamped stuff to escape quickly. The heads, or
shoes, also wear flat and square, and do not present the ragged appearance
of ordinary rectangular-shaped heads after they have been much used.
According to Mr. Husband, of Hayle, the relative resistance offered by
various kinds of rocks to the pulverising action of the pneumatic stamps,
taking the hardness of Clay-Slate to be 1, is as follows :—
Clay-Slate
I⚫00
Broken Fire Brick.
I.00
Mellanear Mine Lode Stuff
West Seton
1.60
1.60
"
Ordinary Cornish Brick
1.24
Blue Elvan (Road Metal)
1.80
Granite or Quartz, of average hardness
Limestone
1.30
Dolcoath Mine Lode Stuff, Hard
1.40
Capel
2.30
Mr. Husband also states that the quantity of stone reduced in a given
time, within certain limits, with heads varying from 2 to 8 cwts. each, is directly
in proportion to the total weight of the head and lifter, each having the same
fall and making a like number of blows per minute.
Scholl's Stamps.-The following are a few particulars relating to Scholl's
pneumatic stamps, erected at St. Just in 1878. Stamps consisted of two heads
and two cylinders. Diameter of steam cylinders 9 inches, stroke 10 inches,
pressure of steam employed 50 lbs., cut off at of length of stroke, number of
beats of each head per minute 140, lift of head 16 to 17 inches, diameter of
head 12 inches.
Patterson's Stamps.-This stamps, known as the "Elephant Stamps,” was
designed by Mr. Patterson to replace the heavy and more costly gravitation
stamps. The novelty of this machine consists in the insertion of a semi-
circular bow and volute spring, between the driving-shaft and the lever.
It is alleged that the spring, acting as a cushion, takes up the greater
part of the wear and tear of the machine, which from the violence of the
CHAP. IV.]
PULVERISING TIN SLIMES.
737
blows would otherwise be considerable-an objection applying to other
machines of this class striking very severe blows, and running at a high
speed.
Power is also economised by the use of springs and steel levers
in place of stamp-rods, guides, and cams, friction being thereby greatly
reduced. The makers, the Sandycroft Foundry Company, attribute many
advantages to the use of these stamps, viz. (1) portability, the heaviest
piece not exceeding 6 cwts.; (2) prospecting purposes—a small battery can
be put to work quickly and driven by horses, mules, or bullocks; (3) saving
of fuel-much less power is required to drive these to accomplish a given
result than is necessary to run the ordinary stamps; (4) elasticity of blow-
the blow struck is the most elastic that can be produced, the sliming of the
stuff being thereby reduced to a minimum quantity, while the weight of blow
can be varied at will from a light blow to that of the heaviest stamp, to suit
the hardness of the stuff to be reduced. The total weight of the machine is
about 2 tons. The mortar-box is made to take three screens, one in front
and one at each end, the screen area being 350 square inches, or 175 square
inches per head. The speed of the crank should be such as to drive the
heads from 180 to 200 blows per minute. The height of blow at such speed
will be about 10 inches. From eight to ten gallons of water per minute will
be required per pair of heads.
At the Indian Consolidated Gold Mines in the Wynaad, Southern India,
where six sets of elephant stamps were erected, it was found that the power
required to run three batteries at 140 revolutions per minute was 11 horse-
power, from which must be deducted the power absorbed in running the
engine, shafting, gearing, and pulleys, amounting to 2.7 horse-power, which
left 8.3 horse-power to be divided among three batteries, or 2 horse-power
per battery. The loss of weight in heads and dies stamping a very hard
keen-cutting quartz was 110 lbs. per 150 tons, or barely lb. of steel per
ton of quartz. The quartz was reduced to pass through screens 800 holes
to the square inch, and about one ton of damp firewood was sufficient to
run a battery at 140 revolutions per minute for a day of 24 hours.
Pulverising.-The difficulty in dealing with slimes with the ordinary
dressing appliances, arises from the circumstance that the grains of tin ore
are very minute compared with the particles of foreign matter with which
they are mixed. They are consequently carried away in suspension by the
water in consequence of their extreme absolute lightness, although their
specific gravity is greater than that of the larger particles of foreign matter
with which they are associated. For the purpose of reducing the particles
of foreign matter to the same size as the tin grains, and thereby enabling the
latter to be separated by the ordinary dressing-machines, several different
"pulverisers" have been introduced, having either a reciprocating or a
rotary motion; these have been found very successful in pulverising the
waste, or “roughs," previously thrown away, because the cost of reducing
the product by restamping was greater than the value of the oxide of tin
obtained.
Dingey's Pulveriser is in successful operation at several mines in Cornwall
and abroad. It consists of a shallow pan 6 feet internal diameter, having
738
[BOOK III.
PRACTICAL MINING.
vertical sides, fitted with a series of grates, through which the pulverised
material is delivered. Four annular grinding discs, or runners, 2 feet
diameter, and geared together, revolve upon the bottom of the pan at a
speed of 200 revolutions per minute, while the pan itself is made to revolve
slowly at four or five revolutions per minute, so as to avoid any tendency
to wearing the grinding surfaces into grooves. The wearing surface of the
bottom of the pan is a separate cast-iron plate, with a number of holes in it
forming shallow recesses, in which the stuff to be pulverised is retained
whilst the grinding runners act upon it. The stuff mixed with a stream of
water is supplied by a launder into a central annular trough, from which it
is delivered by spouts into the centre of each of the grinding runners, and
having been ground by passing under the runners, it escapes with the water
through the grates in the sides of the pan into an external trough, from whence
it is conveyed direct to the buddles. The shoes of the grinding runners, as
well as the bottom of the pan, are separate castings 1 inch thick, so as to
be readily replaced when required. The space between the grinding faces
of the shoes and the bottom of the pan is adjusted by hand-regulating screws
HOPPER
INLETS
OUTLET
WATER LINE
CRAPERO
Fig. 202.
and levers supporting the runner spindles. The weight of the whole machine
is about 4 tons, and it will grind from 15 to 20 tons per day of 24 hours
according to the class of stuff treated.
Michell and Tregoning's Pulveriser, Fig. 202.-This pulveriser consists of a
cast or wrought iron cylinder, a charging hopper, inlet charging pipe, an outlet
delivery pipe, and a wooden tank. The operation of the machine is exceed-
ingly simple. The cylinder is charged with from 12 to 15 cwts. of small scrap
iron, and the sand to be ground is conveyed to the cylinder from the hopper
through a pipe by means of a small stream of water, which can be regulated
at will. The cylinder then revolves, when the movement of the iron grinds.
or pulverises the sand. The scrap iron presents from 40,000 to 50,000
square inches of rubbing or grinding surface, and as soon as the stanni-
ferous sand is ground sufficiently fine it is discharged at the outlet end of
the cylinder. The degree of fineness to which the sand is pulverised is in
proportion to the rate at which it is supplied to the cylinder. A lad 15
years of age attends two machines.
At Wheal Agar, Redruth, a large pulveriser is employed, the inner length
CHAP. IV.]
CUNNACK'S PULVERISER.
739
of the cylinder is 5 feet, diameter 56 inches. The cylinder is fixed in an
horizontal position, and when pulverising hard stuff it makes 16 revolutions
per minute. For soft stuff the speed is reduced to 14 revolutions per minute.
The weight of scrap iron within the cylinder is from 10 to 12 cwts., about
56 lbs. of which is ground up in effecting the pulverization of 30 tons of stuff,
or a loss of 1.86 lb. of iron to one ton of stuff. The following are the rela-
tive proportions of the various sizes of the stuff before entering and after
passing out of the cylinder :-
Grains which would not pass through a wire-wove sieve 6,000
holes per square inch
Grains which passed through a sieve 6,000 holes, but which
would not pass through 12,000 holes per square inch
Grains which passed through a sieve 12,000 holes per square
inch.
Before
Pulverization.
Per cent.
22.3
After
Pulverization.
Per cent.
Nil.
14.8
62.9
100'0
100'0
100'0
The weight of stuff pulverised in 24 hours at a speed of 16 revolutions
per minute is from 5 to 6 tons. The quantity of water required to dilute and
carry off the pulverised sand is from 10 to 12 gallons per minute.
At Wheal Peevor, the burnt leavings afforded by sizing before and after
pulverization :—
Grains which would not pass through wire-wove sieve 6,000
holes per square inch
Grains which passed through a sieve 6,000 holes, but would
not go through a sieve 12,000 holes per square inch
Grains which passed through sieve 12,000 holes per square inch
•
Before
Pulverization.
Per cent.
After
Pulverization.
Per cent.
Nil.
0.2
17.6
10'5
71.9
98.8
100'0
100'0
The following proportions of grain sizes constituted a sample of roughs
from Wheal Uny before and after pulverization :—
Grains which would not pass through sieve 6,000 holes per
square inch
Grains which passed through 6,000 holes, but would not go
through a sieve 12,000 holes per square inch
Grains which passed through sieve 12,000 holes per square
inch .
Before
Pulverization
Per cent.
After
Pulverization.
63.0
Per cent.
Nil.
18.5
I'7
18.5
98.3
100'0
100'0
Cunnack's Pulveriser.-This pulveriser is constructed with a circular
bottom, about 3 feet diameter, surrounded by a shallow pan, a disc 2 feet
diameter, and a vertical crank shaft, for giving the disc an eccentric move-
ment. Renewable grinding-shoes are fitted to the bottom as well as to the
movable disc. The weight of the shoe is about 3 cwts., which, with constant
use, requires renewal once every three months. About 1 horse-power is
The stuff to be
necessary to run the disc 40 revolutions per minute.
pulverised is introduced between the disc and the bottom, and its fineness
or coarseness is regulated by increasing or diminishing the quantity of water
in the pan. At Wheal Uny, Redruth, the weight of stuff reduced per 24
hours with one machine is about 7 tons. A sample of "burnt leavings
2
3 B
*740
[BOOK III.
PRACTICAL MINING.
before and after pulverization was sized through three sieves, when the
following results were obtained:-
Stuff which would not pass through wire-wove sieve 6,000
holes per square inch
Stuff which passed through 6,000 holes, but would not pass
through sieve 12,000 holes per square inch
Stuff which passed through sieve 12,000 holes per square inch
Before
Pulverization.
Per cent.
15.0
After
Pulverization.
Per cent.
Nil.
20.8
64.2
2.6
97'4
100'0
100'0
Nicholas's Pulveriser.-This apparatus is in use at Wheal Uny, West
Basset, Wheal Agar, and other mines in the Redruth district. It consists
of a stationary horizontal cylinder, closed at the ends, 4 feet long and
24 feet diameter; a revolving barrel on an axis, within the cylinder, fitted
with grinding rubbers, a false bottom set within the cylinder, extending
upwards and around for about two-thirds of the inner circumference of the
stationary cylinder; an inlet and outlet passage for the stuff, levers and
weights at the ends of the cylinder, set under the axis, for adjusting the
rubbers, so as to grind the stuff to the required degree of fineness. The
grinding barrel makes from 30 to 40 revolutions per minute. At this speed
about 1 horse-power is necessary, and 6 tons of roughs or 8 tons of burnt
leavings are pulverised in 24 hours. Four samples of stuff, sized before and
after pulverization, gave the following results :-
Wheal Uny.
West Basset.
Wheal Agar.
Burnt Leavings
Pulverised.
Burnt Leavings
Pulverised.
Roughs
Pulverised.
Burnt Leavings
Pulverised.
Grains which would not pass through
sieve 6,000 holes per square inch.
Grains which passed through sieve
6,000 holes, but would not pass
through sieve 12,000 holes per
square inch
Grains which passed through sieve
12,000 holes per square inch
Before. After. Before. After. Before. After.
28.4
2.I 66.0
Before. After.
50'9
1.6
72'9
17.3 3.3 13.7 0.3
54.3 94.6 20'3 99.7
24.I
15'1 15.1
2.9
25'0
83°3 12'0 97.I
100'0 100'0 100'0 100'0 100'0
ΙΟΟ Ο 100'0
100'0
Jordan's Pulveriser.-The machine made by Jordan and Son is formed of
a chamber and two sets of pulverising arms. The following is a short
description of the machine and explanation of its working.
Two circular dished castings, each having a long bearing projecting
from its centre, are bolted together by flanges, and form the crushing
chamber D D, which has an inlet opening on the top E, and two outlet open-
ings, one on each side. The two bearings carry short wrought-iron spindles
which meet end to end in the centre of the crushing chamber. On the inner
end of each spindle is keyed a set of four arms, H H H H, the diameter of the
chamber, the surfaces of the one set of arms being so angled at 45° with the
horizontal centre line that they are parallel to and face those of the other
set.

CHAP. IV.]
JORDAN'S PULVERISER.
741
These arms pass in opposite directions close to each other and to the
sides of the chamber, and their backs are so formed as to create a blowing
or fan action in the chamber, drawing air through openings in the sides and
near the centre of the chamber. On the outer end of the spindles are
keyed pulleys for driving by belts, the spindles and their arms and pulleys
being quite free and independent of each other to turn in reverse direction.
One of the spindles has
worm engaging a wheel, and
working a vertical shaft; it
drives at a given speed the
automatic feeder M. By means
of driving belts on the pulleys,
the spindles and their arms
are revolved in reverse direc-
tions at any suitable speed for
the material to be crushed.
The material falling into the
chamber from the automatic
feeder M is struck by one of
the arms (owing to the angle
of its face) into the path of
those revolving in the reverse
direction, and is by them, for
the same reason, immediately
returned; thus it is with great
force struck to and fro from
arm to arm. There is, there-
fore, no grinding action, the
crushing being done entirely by
percussion or impact, but with-
out centrifugal force. The fine-
DELIVERY
H
M
H
H
FEED.
Fig. 203.
H
DELIVERY
ness of the material leaving the machine is regulated by the current of air,
which immediately takes away, through A A, all particles light enough for the
current to suspend, and the force of this current can be adjusted to the greatest
nicety, by simply closing or opening the apertures in the casing for that pur-
pose. The current in the machine is sufficient to carry the crushed material
up 10 or 20 feet of pipes to another chamber, the height of the column of pipes
regulating also the size of the particles delivered, different sizes being
delivered at various levels if required.
Chilian Mill.-This apparatus, for the reduction of silver ores and
amalgamating purposes, is employed to a limited extent in Australia. A
single runner, 6 feet diameter, 16 inches thick at the edge, running 200 feet
per minute, will reduce about 7 cwts. of stuff from grain sizes of 10 to 60 holes.
per lineal inch per day of 24 hours.
Horizontal Mill.-A mill constructed of flat burr stones, almost similar to
a flour-mill, is found to grind certain ores very effectively, although but a
limited weight is produced in a given time. A stone 4 feet diameter and
12 inches thick, and a runner 14 inches thick, the latter making 100 revolutions
3 B 2
742
[BOOK III.
PRACTICAL MINING.
per minute, will grind 1 ton of stuff from a mesh size of 100 holes to 3,600
holes per square inch in a period of 10 hours.
Carr's Pulveriser.-This apparatus is formed of two disintegrating wheels
placed in a close case. On the face of each wheel is a series of projecting
pins, which are so arranged as to revolve concentrically with each other.
The wheels rapidly revolve in opposite directions, and the stuff falling into
the apparatus is projected from one pin to another with great velocity and
shattered into dust. Wheels, 6 feet diameter, for the reduction of copper or
silver ores, making 500 revolutions per minute, reduce from 5 to 6 tons of stuff
per hour, and require 20 horse-power.
Arrastre.-The Arrastre is, perhaps, one of the rudest and most simple of
all pulverisers. It includes a vertical spindle of wood, a couple of wooden
arms, a closely-laid stone bottom, and a wood or stone ring to form a basin.
Two basaltic or other hard stones are used as runners, which are dragged
upon the bottom frequently by mules, but sometimes by means of steam-
power. A machine in good working condition will grind from 600 to 800 lbs.
of ore into very fine slime or mud in 24 hours.
TABLE OF MILL RESULTS.
No. of Holes in
Grate or Screen.
Weight of Stuff
ground in
10 Hours.
Approximate
Horse-power.
Cost per
Ton.
Ordinary Crushing Mill Rolls, 21-inch
diameter, speed of Rolls 42 feet per
minute
Ordinary Cornish Stamps per head
""
dry stamping
Husband's Stamps, I head, 9 cwts.
Elephant Stamps, 2 heads, each 4 cwts.
Ordinary Californian Stamps
8oo holes per
square inch
o to 3 mm.
o to
21
I
Tons.
s. d.
o to 7mm.
25
6
09호
​0 to 3 mm.
Grate holes
I
11
I per head
O II 1/
å mm. diamtr.
13 to 15
16
""
6,, 7
I
Aww xw
""
""
H
""
Horizontal Mill
( 3600 holes per
square inch
I
5 per mill
2 3
Chilian Mill
Arrastre
oka-ko
2
72
6 10
""
•
(D.) Sizing Apparatus. — When the velocities of the fall of grains of
stuff in water materially differ from each other, then the number of sizing
and classifying divisions may be few; but when the specific gravities of
several veinstones are closely allied to each other, then the classifying
arrangements must include a greater number of subdivisions. The integrity
of this principle should be strictly adhered to without multiplying the
number of sizes beyond what may be requisite for economical purposes.
Too great a refinement in the division of stuff will involve a needless com-
plication in the machinery as well as undue cost for plant; on the other
hand, neglect of the fundamental principle of sizing will most certainly entail
unnecessary cost in dressing and loss of ore in castaways.
Sizing Plates.-The plates are made either of charcoal iron, puddled steel,
cast steel, or copper. The dimensions vary with each metal, and with the
thinness of the plates themselves. Plates perforated with holes from milli-
metre to millimetre are about 3 feet long by 2 feet wide, while holes of
CHAP. IV.]
PERFORATIONS IN SIZING PLATES.
743
greater diameter are made in plates 6 feet long by 3 feet wide. Small holes
from millimetre to 1 millimetre require to be made one diameter apart;
holes exceeding these dimensions may be closer together; above 5 milli-
metres diameter the distance need not exceed one-third of a diameter of the
hole itself. The holes in sizing plates are strictly round and free from burr.
For sizing stuff from millimetre to 1 millimetre copper plates are often
employed. Stuff from 1 millimetre to 50 millimetres is separated on plates
of iron or steel. The holes in sizing plates run from millimetre or one-
fiftieth part of an inch to 50 millimetres or 2 inches in diameter. From
millimetre to 3 millimetres the diameter of the holes advances with a
difference of millimetre, from 3 millimetres to 13 millimetres the increase
is millimetre between each several size, while from 13 millimetres to 50
millimetres it is 1 millimetre.
1
2
I
1
Fig. 204 illustrates portions of plates perforated with holes one, two, three,
four, five, seven, ten, and fifteen millimetres diameter. These holes give a
I Millimetre.
2 Millimetres.
3 Millimetres.
4 Millimetres.
5 Millimetres.
7 Millimetres.
10 Millimetres.
15 Millimetres.
Fig. 204.
distinct idea of millimetre measurement, invariably used on Continental
dressing-floors in defining the grain-size, or dimensions of stuff.
The annexed table affords particulars relative to thickness, weight, and
measurement of plates pierced with holes ranging from 1 millimetre to
50 millimetres diameter.
4
1
The Continental definitions for stuff on the dressing-floors have no fixed
and equivalent expressions among British miners; we must therefore be
content to employ terms of an indicative, rather than of a determinate
character. The designation, therefore, of stuff from o millimetre to milli-
metre is, slime sand; from millimetre to 1 millimetre, fine sand; from 14
millimetre to 3 millimetres, coarse sand; from 3 millimetres to 7 milli-
metres, coarse grain stuff; and from 10 millimetres to 50 millimetres, rough
stuff. Slime and fine sand, o millimetre to 1 millimetre, is divided by means
of classifiers, whilst products ranging from 1 millimetre to 50 millimetres are
sized by the use of flat sieves or trommels. Slime and fine sand are usually
1
2
744
[BOOK III.
PRACTICAL MINING.
treated on buddles, tables, or in jiggers; coarse sand and coarse grained stuff
in jiggers; and rough stuff, partly in jiggers and partly disposed of by hand
picking.
TABLE OF SIZING PLATES.
Iron or Steel Plates.
Thickness
Diameter of
Holes in
Millimetres.
HACH
I
2
2 2중
​WPIHPKOF[/
H-HN
34
54-7
234
of Plate
in Milli-
metres.
A/
| |
Alooooo-kundKSH
I
I
I
I
I
I
PRONH
1×2 2 2 3 3
~ 23457
ت
72-10
10-15
154-25
Approxi-
mate Weight
of Plate per
Square Foot.
Maximum
Size of
Plate.
Thickness
Copper Plates.
Approxi-
of Plate mate Weight
in Milli- of Plate per
metres. Square Foot.
*7 lbs.
I'
""
1.3",
I'5",
1.7 ",
I'9",
3 X 23 ft.
4 X 2 ft.
4 X 3 ft.
5X3 ft.
I
2'4",
ه به به بیایی
3°
"
3.2,
3'5",
4°
>>
6X3 ft.
15000/+
⚫6 lbs.
.8
Maximum
Size of
Plate.
4 X 3 ft.
""
I
I'
""
1
11/0052/00cc)+
2 2 2
14-2
5 X 3 ft.
I'I
""
I.2
وو
1.5 ",
1.6
""
6 X 3 ft.
1.8
2'
""
251-50
The diameter of the sizing holes usually employed for mixed ores, galena,
blende, and spathic iron is for-
Rough and coarse grain stuff
Coarse sand
•
15, 10, 71, and 5 millimetres.
Fine sand.
5, 3, 2, and 12
1 to millimetre.
In practice other divisions are employed, as will appear evident from a
perusal of the following table, but in each mine it will be obvious that the
sizing numbers approximate to those already stated, the difference being,
perhaps, in some measure due to the necessity of enriching ore associated with
gangue, in which there is but little difference in their respective densities.
TABLE GIVING THE DIAMETER IN MILLIMetres of HolES IN VARIOUS SIZING TROMMELS.
Angleur, Belgium (lead glance, blende, and iron pyrites), 25, 20, 18, 16, 12, 10, 8, 6, 5, 4, 3, 2, 1, 3.
Commern, Prussia (lead glance and quartz). To crusher, 18-10; to jiggers, 8, 6, 4, 3, 2, 1; buddles and
tables, -0.
Wildberg, Prussia (lead glance, carbonate of iron, and quartz). Picking-tables, 25-16; to jiggers, 10, 6,
4, 3, 2; to fine sand jiggers, 11, 2, 1; to buddles and tables, -0.
Lohmansfeld, Prussia (lead glance, blende, copper, and carbonate of iron). To jiggers, 20, 15, 10, 5, 3, 2;
to stamps, I; to jiggers and shaking-tables, O, I.
Alltgluck, Prussia (lead glance, blende, and carbonate of iron). To jiggers, 16, 12, 9, 6, 4, 3, 2; to
tables, 1, 2, 0.
3
I,
Bad Ems, Prussia (lead glance). To picking-table, 30, 20; to jiggers, 13, 9, 8, 5, 3, 2, 1; to tables and
buddles,, 0.
Berzelius, Prussia (lead glance and blende), 10, 8, 6, 4, 3, 2, 1, 3.
Iserlohn, Prussia (calamine, lead glance, &c.). To jiggers, 18, 13, 101, 8, 6, 5, 4, 3, 2, 1, 1; to tables,
0.
Mine in Linares district, Spain (lead glance). To jiggers, 10, 7, 5, 21; to buddles, 1, 0.
Burra Burra, South Australia (carbonate of copper, quartz, ferruginous clay). To jiggers, 18, 13, 10, 71,
5, 31, 2, 11, 2; to fine sand jiggers, 4, 3, .
3
志
​4
The separation of stuff into grains of different sizes can be effected either
by a combination of flat-bottomed sieves or by a set of revolving trommels.
Flat sieves may be arranged for sizing purposes as a series of steps, fitted
}
CHAP. IV.]
TROMMELS OF DIFFERENT KINDS.
745
within a long inclined trough or set in a rectangular frame; they may be
also rendered movable or stationary. In the latter case the stuff must be
mechanically agitated and passed across the plates. The angles at which
movable sieves are set is usually about 18°, the length of stroke given to
them 1 inch, and number of strokes per minute 200. The sizing effect can
be produced either by a cam, shuttle, or crank, and any shock movement may
be intensified by the use of wooden or steel springs. Flat sieves have been
extensively employed in Austria; but of late years the dressing works of
Prussia and Belgium have been almost entirely fitted with trommel sieves.
The disadvantages attending the use of flat sieves lie (1) in the amount of
dead weight to be moved for securing a given result; (2) in the difficulty
of sizing the finer divisions of stuff without the agency of water; and (3) in
certain complications due to cam, lever, or crank arrangements. On the other
hand, flat sieves are replaced with facility, and the sizing, proceeding from
large to small grains, leaves the thinner and more finely-perforated plates
free to do their work effectively.
Although trommel sieves admit of simple arrangement in connection
with the driving appliances, and consist of well-balanced parts, yet none
of the several forms can be said to be strictly free from objection; simplicity
is sometimes secured by inverting the sequence in which the sizing of the
stuff is best performed, while if the proper order of separating the grains,
that is, from the greater to the lesser sizes, is retained, it frequently happens
that the apparatus requires a considerable height of ground, or that the
result is only achieved by employing several concentric cylinders revolving
on one common axis, which cylinders become difficult of access when wanting
some very slight but necessary repair. In order to effect a thorough division
of the grains by means of revolving trommels, water should freely enter into
and fall upon the cylinders. The crushed stuff should therefore drop into a
stream of water, and water should also be delivered to the outside of the
trommels from distributing launders or pipes. The names given to trommel
sieves accord with the work they perform; as, for example, clearing trommel,
for clearing vein stuff of associated clay and earthy matter; separating
trommel, for dividing fine and coarse-grained stuff for the sizing trommels;
sizing trommels, for sizing stuff for jiggers and buddles; and draining
trommels, for ridding sand of water. Cylindrical sizing trommels require
to be set at angles varying from 3° to 5° in order to pass the stuff from the
entering to the discharging end. The axis of a conical-shaped trommel may
be strictly level, since the falling angle of the perforated shell, usually about
3°, combined with its rotative movement, will suffice to impel the stuff from
the smaller to the larger end.
3
Hand Riddle.-The simplest form of sizing apparatus is the hand riddle,
which is formed of a hoop of oak 18 to 20 inches diameter, of an inch thick,
and 6 inches deep. The bottom consists of a meshwork of copper or iron
wire of a gauge suitable for the intended work.
Circular Hand Riddle.-This riddle consists of a cylinder of wirework
mounted in a frame with a handle at its lower end. The meshes of the sieve
when applied to riddling copper ore vary from 3 to 1 inch square, according
to the character and quality of the vein stuff to be separated.
4
746
[BOOK III.
PRACTICAL MINING.
A
B
3
-
Continuous Cylindrical Trommel.-This trommel is shown in Fig. 205.
The stuff entering at the farther end from the driving-rigger, passes to
the millimetre section, then successively over the 2, 11, 2, and 3 milli-
metres divisions. The thin plates are supported by lateral bars fastened
to the rings within and without the cylinder, one of such bars being
shown. Wrought iron
rings about 1 inch wide
and inch thick divide the
cylinder into sections, and
serve as fasteners for the
plates and for connect-
ing the radial arms pro-
ceeding from the central
bosses. The order in which
3/2
1
2
3
Fig. 205.
the sizing is effected in this trommel sieve is from small to large grains;
consequently, the initial quantity of stuff passes first over the thinnest plate,
and, in the absence of careful feeding, the fine millimetre holes may be
overcharged, when an imperfect sizing will be the result; on the other hand,
the separation being performed on a continuous line without a material loss.
of fall, this trommel is a useful one for many dressing-floors. The angle at
which these trommels should be set is from 3° to 5°. The diameter of the
trommels runs from 2 to 3 feet, the number of revolutions per minute from
18 to 25.
Continuous Conical Trommel.-This trommel includes different sizing
divisions, but instead of being a true cylinder the form of the perforated shell
is that of a truncated cone, running from the axial line at an angle of from
3° to 4°. The sequence in which the sizing is effected is the same as in the
continuous cylindrical trommel.
Single Conical Trommel.-The trommel, Fig. 206, may form one of a set
Fig. 206.
for sizing stuff from a clearing
trommel or crushing mill. The
order in which the sizing oc-
curs will be from great to small
grains, hence the thinnest plate
and smallest holes will be sub-
jected to a minimum amount
of wear. A system of six
trommel sieves, each 42 inches
long, diameter at large end
21 inches, and at small end 18 inches, making 20 revolutions per minute,
will size from 20 to 30 tons in 10 hours. The water required for the six
trommels will be from 12 to 15 gallons per minute. In order to convey the
stuff from one trommel to another, a sheet-iron or wooden hopper may be
employed. When a set is fixed step-like, one above another, on a running
angle of, say, 40°, the driving gear may consist of a shaft and bevel wheels;
but the necessary motion may also be communicated by a light side-rod and
cranks, in connection with a small fly-wheel. At Angleur, in Belgium,
where the stuff from the clearing trommel is divided by seven trommels into
CHAP. IV.]
SPEED OF CONTINUOUS TROMMELS.
747
fourteen sizes, each sizing trommel is 20 inches diameter and affords two
divisions of stuff, viz. front division, 25, 20, 14, 10, 5, 3, 1 millimetres; back
division, 60, 16, 12, 8, 4, 2, 1 millimetres. Some single trommels, designed
by Darlington, for sizing coarse-grained stuff and sand, have a diameter of
24 inches at the small end and 28 inches at the large end, with a sizing
length of 38 inches, and make 20 revolutions per minute. The sizing
capacity of a group of 10 trommels making 20 revolutions per minute is
about 8 tons per hour. The preference for cascade or step-like trommels is
due to several features, among which may be noticed that the sizing takes
place in the proper sequence of numbers, that is, from large to small grains.
Each trommel usually excludes but one sort of grains and passes all grains
smaller than the sieve-holes through the latter, whereby a better separation
is effected than with continuous trommels numbering several divisions.
Large grains do not pass over the fine-hole sieves, and cause undue wear.
Each trommel is light, portable, and cheaply duplicated and replaced.
Against these manifest advantages, however, must be placed the many parts
necessary for driving a system of trommels and the loss of fall arising from
the descent of stuff from one trommel to another.
Double Conical Trommel.-For the purpose of obtaining three distinct
separations of stuff in a short length, and without incurring much loss of
fall, two concentric conical trommels are employed. Their use is, how-
ever, not so much for sizing as for dividing stuff for the sizing trommels.
Continuous Conical Trommel.-With the view of lessening the fall incident
to single sizing trommels minimising friction, and securing the proper order
in which the sizing operation is best performed, continuous trommels have
been designed by Rittinger, Huet, Geyler, and others. Darlington and
Green have also arranged a series of conical trommels without much loss.
of fall, and well adapted for sizing lead or copper ores.
TABLE OF PARTICULARS RELating to Speed, DIMENSIONS, AND LENGTHS OF CONTINUOUS
TROMMELS USED AT VARIOUS MINES.
Diameter
Name of Mine.
of Trom-
mel in
Revolu-
tions per
Minute.
Inches.
Length
Length of each Sizing
of Trom-
Portion of Trommel in
mel in
Inches.
Feet.
Diameter of Hole in
cach Length of Trom-
mel in Millimetres.
, 1, 2, 3
4, 6, 8, 10
4, 6, 9, 12, 16
I, 2, 3
I, I, 2, 3, 4
20, 15, 10, 5
15, 10, 5, 3
I, 2, 3
1, 2, 31
Berzelius.
Altgluck.
Lohmansfeld
""
36
36
32
33
2 2
32
36
4422 2
I2
14
14
48, 36, 24, 14
30, 26, 18, 16
ΙΟ
12
40, 30, 27, 21, 17
37, 38, 36, 32
ΤΙ
I 2
12
33, 22, 20, 13, 13
•
24
24
12
Wildberg
Iserlohn
""
•
22
•
~ | ww
30
24, 24, 24, 24
24, 24, 24, 24
24, 24, 24
11 29∞∞6
19
8
8
20
30, 30, 30
24
20
30, 30
36
12
38, 22, 28, 24, 19
II
36
ΙΟ
34, 29, 35, 21, 18
IO
دیار
بیاره
conical.
Burra Burra
Minerzhagner.
";
12
•
30.48
21, 24, 27, 30, 36
12
30.48
23, 27, 29, 34, 48
9
32.48
36, 36, 30, 18
ΙΟ
30
1333
14
30.41
30, 33
I2
"
30.48
54, 42, 36
I I
12
""
•
30.48
42, 36, 36, 36
12:
12
""
30.42
39, 39
-6-
SH2 6
5/1/
6/1/2
3
1
2, 10, 13, 18
3
1, 11, 2, 31
18, 13, 10, 7, 6
31, 2, 1, 3,
6, 6, 10, 18
I, I
7, 8, 9
4, 6, 8, 10
3, 2
748
[BOOK III.
PRACTICAL MINING.
(E.) Classifying Apparatus.—Fine sand and slime claim the especial atten-
tion of the dresser, seeing that the quantity in some dressing works is often very
considerable, and in many instances exceeds that of the coarser stuff produced.
The isolation of finely divided ore from sterile sand is but seldom accomplished
direct, some preparatory treatment being necessary so as to bring the grains
within the scope of particular concentrating apparatus. Connected with the
enrichment of fine sand or slime it may be observed-
1. When light particles are suspended in water, the natural resistance
opposed to the freedom of their descent is affected by the slightest current in
the water itself or by the contact of particles among themselves, either
circumstance modifying the direction that each separate grain would take
if it were permitted to obey the simple action imparted to it by its own
specific weight, and preventing it from obtaining the position due to it from
the action of gravity alone.
2. The form of the particles may under certain circumstances be a cause
of derangement, and may acquire an influence all the more important from
the minuteness of the grains themselves. As an example, thin scales of
sulphide of lead and malachite are known to float on the surface of water
in spite of their natural densities.
3. Particles of sand, so minute as not to settle readily in water, or when
settled agglomerate into a tenacious slime, must occasion a loss of orey
constituents, as well as much labour in the enriching process.
The great waste, cost, and difficulty attending the dressing of fine sand
slime render it, therefore, of the highest importance to arrange continuous
working apparatus, so as to lessen the item of labour, and to pass the stuff
from one stage of treatment to another while it is freely suspended in water,
in order that the ore may be the more readily concentrated in the various
machines.
As sizing trommels for fine slimes are altogether useless, and as the effects
due to specific weights are less readily under control with the diminishing
size of the particles, it has been found necessary to effect a classification of
grains by bringing other principles to assist the density of the grains them-
selves. In order, therefore, to effect the concentration of classified grains,
advantage is taken of the greater or less amount of frictional surface which
they offer to a stream of water flowing over flat or slightly inclined tables,
such as buddles and frames.
The difference in the density of particles composing a mixture of stuff
will also assist in the separating process, for with regard to two bodies the
volume of each being equal, but of a different density, the frictional surface
on a table, although the same, will in the lighter substance offer less retard-
ing action than the heavier one; the former will, consequently, move more
rapidly than the latter and separate from it. In addition, the smaller a
grain or particle is, the more important will the surface become in comparison
to its specific weight, and the difficulty of separating ore from gangue will
also increase in proportion as the grains become finer, since the resistance
to movement depending on weight decreases more rapidly than that of the
influence exercised by the current on the surface of the particles.
The grains submitted to the action of stream and classifying apparatus
CHAP. IV.]
SEPARATING CYLINDERS AND TROUGHS.
749
may vary in their dimension from 0 to 1 millimetre. In continuous stream
cylinders only two classes of sand are usually produced, but classifying
troughs will afford a separate classification for each of its divisions, while a
set of classifying cones will give a distinct class of grains for each distinct
cone.
The oldest classifying arrangement is the labyrinth, or settling-pits. To
three coffers containing nine stampers, four pits were formed, each of which
increased in width from 1, 14, 11, to 12 foot, and in length from 15, 21, 24, to
36 feet, with inclinations in the same sequence of 1, 1, and inch per foot,
1,1,
the floor of the largest being horizontal. Such a system of pits classified
the stuff into four sets of grains, the coarser grains being lodged in the first
or narrowest pit. This classification was, however, never very perfect, be-
sides which the method entailed some expense in clearing the pits and in
preparing the products a second time for further treatment. In addition, the
loss of fine sand was generally from 10 to 15 per cent. of the initial weight.
Separating Cylinders.-In this apparatus a simple division of the sand is
effected by maintaining the influx at a greater height than the efflux of a
stream of water, thereby producing an upward hydrostatic pressure. The
sand and water are introduced between an outer and inner cylinder, clean
water is added through the inner cylinder, when fine sand and water will
escape through the annular space between the two cylinders, while the
heavy grains may flow through a small pipe in the bottom of the cylinder
about inch in diameter. This pipe is provided with an adjusting plug or
slide for regulating the proportion of stuff to be discharged both at the top
and bottom of the apparatus. The cylinders may be formed of sheet zinc,
LONGITUDINAL SECTION
α
a
b
CROSS SECTION
Fig. 207.
the short central one (say) 7 inches in diameter, the other two respectively
8 and 9 inches in diameter. The length of the outer cylinder may vary from
4 to 5 feet.
Pyramidal Troughs, Fig. 207, as their name implies, are hollow, rectan-
gular, pyramidal boxes. They are usually constructed of strong boards.
well joined together. The sides are inclined at angles of not less than 50°,
and there is a small hole in one side close to the apex. They are fixed
750
[BOOK III.
PRACTICAL MINING.
horizontally in an inverted position, and the crushed material is introduced
at one of the narrow ends, a few inches below the top, by means of a
launder. The result is that, as soon as the box is filled, a certain portion of
the crushed matter, i.e. the coarsest and heaviest, which the water on
account of its diminished velocity is not able to carry farther, sinks and
slides down the inclined sides of the pyramid and escapes through the small
hole a near the apex, whilst the finer and lighter matter passes off at the
top by an outlet b in the centre of the end opposite to the point of entrance.
If now a second larger box be attached to the first, a third still larger one
to the second, and so on, each succeeding box at a slightly lower level, in
order to prevent any settlement of stuff in the passage ways, it follows not
only that the same process of settling and escaping of the particles from the
apex will take place in every box, but also that their size will decrease
nearly in inverse proportion as the surface of a succeeding box is larger than
that of the preceding one, or directly as the velocity of the water is dimi-
nished in it. According to this principle of the boxes, if they were made of
only very gradually increasing size, and the apex holes proportionately small,
it would be possible to classify the stuff into several sets of equivalents before
it entirely settled, ¿.e. till clear water passed off from the last box. Expe-
rience has, however, shown that for fine-ore dressing in general, classifica-
tion into four different sizes by an apparatus of four boxes is quite sufficient.
The size of the different boxes, in order to insure the most perfect classifica-
tion, depends both on the amount of material which has to pass through
them per second and the size and character of the grains, and by theory
and practice it has been found that for the supply of every cubic foot of
material the width of the first or smallest box must be foot, i.e. for
instance, for 20 cubic feet 2 feet, and for every succeeding box it ought to
be about double that of the preceding one, or, generally, the widths of the
boxes must increase nearly in geometrical progression 2, 4, 8, &c., and their
lengths in an arithmetical one 3, 6, 9, &c. Their depths depend on the
angle of inclination of the sides, which, as already stated, is generally 50°,
because, if less, the stuff would be liable to settle firmly and choke the
central orifice, and, if larger, unnecessary greater height of the boxes would
be required. The form of the two smaller boxes is commonly such that the
two short sides are inclined at the above angle, and the two long ones which
would become far steeper are broken, i.c. are for a certain depth from the
top vertical, and afterwards inclined at the normal angle. This modification
has, however, no influence upon the action of the boxes, but simply facilitates
somewhat their construction and firm fixing. The sides of the larger boxes
are generally even throughout. The way in which the outlet-holes a at the
apices are constructed has an important bearing on the operation of the
boxes. At these points the hydrostatic pressure is considerable, and the
holes would naturally be kept small in order to prevent too much water
passing with the particles of stuff; such small outlets are, however, especially
in the treatment of coarser material, very liable to become choked. This
difficulty has been met by the holes being made of conveniently large size,
but connected with pipes, c, inch in diameter, which rise up the sides of the
boxes, i.c. of the smallest box to within 3-31 feet, and of the others to
CHAP. IV.]
TRIANGULAR DOUBLE TROUGHS.
751
within 2—2 feet from the top, and are there furnished with small mouth-
pieces d, supplied with taps for regulating the outflow. This arrangement,
on account of the outlets being so much higher, has the further advantage
that a considerable amount of fall is gained (especially as regards the large
boxes) which for the subsequent treatment of the material is in some cases
of special value. There are two more points that require attention in order
to insure good action of the apparatus, namely, the introduction of the
material into the different boxes equally and without splashing, and, further,
to prevent the entrance of chips of wood, gravel, or other impurities that are
likely to stop or otherwise obstruct the outlets. The first point is met either
by having the supply-launders expanded fanlike and furnished with dividing
ledges, b, or by the interposition of small troughs, the sides of which, nearest
the box to be supplied, are perforated near the bottom by equidistant small
holes. The cleaning of the material previous to its entering the first box is
generally effected by the main supply-launder being made a little wider near
the point of entrance, and the insertion at this place of a fine wire sieve across
the launder, and somewhat inclined against the stream. This sieve must be
occasionally looked after to remove any impurities collected in front, and
this, in fact, is the chief attention the whole apparatus requires, for otherwise
it needs hardly any supervision; if once in proper working order its action
is constant and uniform, provided the material introduced does not change
in amount and quality; and it has this further advantage, as compared to
the slime labyrinths, that the classified stuff can from the outlets be directly
conveyed in small launders to the concentration machines for treatment
without any previous preparation. One point, however, not in favour of the
apparatus is that, having to be placed between the reduction mill and the
concentration machines, a great fall of ground is required to permit the direct
introduction of the material, and also to allow sufficient fall for the tailings;
and thus, where local circumstances are unfavourable, it has to be erected at
a higher level and necessitates the use of dipper wheels or other suitable
appliance for lifting the stuff. The action of the different boxes on certain
slimes, with regard to the percentage of fluid matter and the quantity and
character of the solid contents respectively separated, was, according to
some experiments, as follows :-
The small box separated 38-40 per cent., which contained per cubic foot
16-18 lbs. coarse sand.
The second box separated 20-22 per cent., which contained per cubic foot
13-14 lbs. fine sand.
The third box separated 18-20 per cent., which contained per cubic foot
15-16 lbs. coarse slime.
The largest box separated 10-12 per cent., which contained per cubic foot
10-12 lbs. fine slime.
Triangular Double Troughs.-Another method of classification, effected
by means of double triangular troughs, "Spitzlutten apparatus," is based
upon the principle that if material composed of particles different in size and
density is exposed to a rising stream of water, the velocity of this stream
may be so regulated that particles of certain size and character (equivalents)
sink, and may be conveyed to concentrator, whilst the remainder is carried
752
[BOOK III.
PRACTICAL MINING.
upwards. Consequently, by repeating this operation a certain number of
times with a gradually decreased velocity of the rising stream each time, the
material can thereby be separated into as many different classes of grains.
The troughs, Fig. 208, by which this action is produced are constructed
as follows: Within a triangular trough a of certain length and width,
with two opposite sides vertical and two inclined at angles of 60°, is
a similar small one b having the vertical sides in common with the larger
trough, but its inclined sides fixed at certain equal distances from and
parallel to those of the latter. There is thus an open V-like space c left
between the inclined sides of the two troughs, representing, as it were, a
rectangular pipe sharply bent in the centre; and it is through this that
the stream of material has to pass, i.e. to fall and rise. The velocity
of the stream depends on the size of this space, and also the size of the
particles that will rise or sink in it. The cross section and respective
LONGITUDINAL SECTION
CROSS SECTION
YY #
a
e
Ъ
PLAN
Fig. 208.
velocity stand in inverse relation to each other, and their determina-
tion for each double trough of a complete apparatus is a matter of
mathematical calculation in which the size of the largest particles and the
specific weight of the material to be classified form the main figures. For
ores crushed so fine that the largest grains are not more than o·6 millimetre
in diameter, the most satisfactory classification into four different kinds of
grains is arrived at by a series of four double troughs, with the velocity of the
stream decreasing from the first to the succeeding troughs, in the progression
of 2*3, 0*94, 0*37, 0.15 inches per second, and if the width of the channel for
the first trough is 1'1 inch, and its length 2 feet, the dimensions of that of the
second trough follow as 2.75 inches is to 2 feet. And as it is not advisable to
increase the width of the channels beyond 3 inches, the channels of the third
and fourth troughs are each 3 inches wide, and respectively about 54.5 inches
and 135 inches long. The mean depth of the channels, measured from the
line of inflow of the material to the lowest part of the inside trough, is for the
CHAP. IV.]
CLASSIFYING TROUGHS AND LAUNDERS.
753
two smaller double troughs about 3 feet, for the two larger ones from 4 to 6
feet. In order to carry off the coarse particles that sink in the channels, the
inclined sides of the outside troughs do not meet below, but are continued
downward, forming a long and narrow pyramidal opening d, about 1 inch
wide at top. The short sides e e, slope inward at an angle of not less than 50°,
contracting the opening to a small hole f, of about 1 inch square at
bottom, through which the material is discharged into an horizontal pipe g,
cross section, that extends both ways a small distance beyond the sides of
the apparatus, and is connected at the ends with vertical 1-inch pipes. One
of these, h, serves for the outlet of the classified material, and is carried up
to within 36 to 21 inches of the water level in the channel c, according to
the degree of fineness of the particles that have to pass through it (the same
as in the pyramidal boxes). At the top it is supplied with a tap for
the regulation of the outflow. The other pipe k, cross section, conveys a
supply of clear water furnished from a launder, l, supplied with a tap m, and
as the water in the pipe stands 6 to 8 inches above the water level in the
trough a small uniform pressure is produced, causing a forced influx of water
at the point ƒ, which is essential for good classification. This water oppos-
ing itself to the downward current charged with sediment in the pyramidal
channel d, prevents all but the coarser particles and pure water passing into
the pipe h, and thus only grains of the desired size are carried to the outlet
i. With regard to the relative positions of the different double troughs of
the series, they are fixed exactly horizontal, and sufficiently below each
other to prevent any settlement of material in the communication launders,
which are necessarily very broad. Other particulars regarding proper work-
ing, supervision, &c., are the same as those given for the pyramidal boxes.
According to experience a series of four of these double troughs classifies as
well, and for the two coarser kinds even better and cleaner, than a set of
four pyramidal boxes, though for the fine slimes the latter are generally
preferred, as they effect the desired settlement of the stuff more completely.
A complete apparatus of troughs requires also less fall and space than one
of pyramidal boxes, and is more easily regulated in cases of increased or
diminished influx of material. As regards the results of classification by the
different troughs of the series, they are approximately stated as follows:
The first or smallest trough separates from the material supplied about 30
per cent. coarse sand; the second trough about 25 per cent. fine sand; the
third, 20 per cent. coarse slime; the fourth, 15 per cent. fine slime.
Classifying Launder.-In some dressing works, fine sand from the top of
classifying cylinders, and from fine-grain sizing trommels, flow into an
expanding launder, in which the particles are classified and collected accord-
ing to their equivalents. The total length of one of these classifying launders
is 28 feet 4 inches. The trough, including the first four divisions, 10, 13,
17, and 22 inches wide respectively, is 3 feet deep and 6 feet 8 inches broad
at the top, with one side set at an angle of 45°, the other at 60°. The second,
connected with the first trough, contains five divisions, each 29, 39, 52, 67½,
and 881 inches wide, 7 feet 7 inches broad, and 4 feet deep. The stream
launder at the entrance of the slime water is 10 inches wide and 4 inches
deep. From this point to the further or outflowing end the width is gradually
754
[BOOK III.
PRACTICAL MINING.
1
4
increased to 36 inches, and the depth to 18 inches. Along the bottom is a
continuous opening inch wide. The water launder which carries the
stream launder is 40 inches wide and 6 inches deep, and is pierced with plug-
holes I inch in diameter.
The gradual widening of this launder occasions a corresponding decrease
in the velocity of the stream and a deposit of grains in the several hutches
according to their respective equivalents. This necessary result is assisted,
and subject to modification, by allowing more or less clear water to pass
C!!
Slut om
Slot L
Life and Waste
A
E
F
B
H
Φα
هن
C!
UL.
C
Water a
P
A
B
to
C.
Slots Wide
Water and Waste
E
ω
A
B
C
D
"Supt /sin Wide
E
Water
Fig. 209.
through the plug-holes. The distance between each plug-hole in the
water launder is progressively greater as the stream launder widens. This
feature is one of great moment, inasmuch as the volume of water is thereby
lessened with the decrease that occurs in the equivalent value of the
grains. A small classifier, made of wood, for classifying grains of lead,
copper, or tin ore is shown in Fig. 209: L, longitudinal section; P, plan; c",
cross section on line of longitudinal section; E, F, C', second cross section
on line C D; and c", a third cross section on line A B. The launder A into
1

CHAP. IV.]
SEPARATORS AND CLASSIFIERS.
755
classifier is 11 inches wide and 5 inches deep, the narrow end of classifier is
16 inches and the wide end 30 inches wide. The discharge launder, E, is
24 inches wide. The first compartment, B, is 16 inches, the second, C,
24 inches, and the third, D, 30 inches long. Clean water is admitted into
the classifier through plug-holes in the side launder, H, while the equivalents
and a certain quantity of water pass through long slot openings adjusted
Fig. 210.
by plates, A, set near the bottom of each receptacle. The outlet-pipes at the
bottom of the receptacles are formed of wood, the holes being to inch
diameter. The course of the clear water and outflow of stuff is shown by
small arrows on the transverse sections. Wood plugs serve to regulate the
volume of water which passes into each receptacle.
Hodge's Classifier.-The inventor claims for this apparatus (Fig. 210):
first, the machine is self-acting, and is cheaply maintained; second, a small
3 C
756
[BOOK III.
PRACTICAL MINING.
volume of water is sufficient for effecting the classification of grains of metallic
ores and sand. He also observes that the success of dressing is found in
treating stuff composed of grains of the same size as nearly as possible: for
instance, a buddle, whether round or flat, will give the best result if the stuff
supplied to it be of the same size; again, if it be required to "pack" a kieve,
the best and cheapest method will be found in treating stuff composed of
nearly uniform grains, whether it may be classed as rough, medium, or slime
ore.
In the classifier, the first division will give coarse grains, the second
grains of less dimensions, and the third a group of still finer grains.
The valves, regulated by means of screws, are adjusted so as to classify
stuff for treatment on buddles, or frames. The water in the supply launder
must, if possible, be clean, so as to free the grains from any viscid slime
which may adhere to them.
Cone Separator.-Fig. 211 shows a cast-iron cone separator, which is fre-
D
C₁
E
о
Fig. 211.
quently introduced between the riddle of the crushing rolls and sizing
trommels. When put into this position its use is to divide the stuff into
slimes, grain size 0-1 millimetre for buddles and tables, and sand from 1
to 6 or 7 millimetres for sizing and treatment in jiggers. A set of such sepa-
rators, that is, one placed below another, properly adjusted, will also prove
excellent classifiers. The stuff, with a sufficient volume of water, enters by
the shoot A into the opening B and falls in the direction of the arrows
against a rising current of water from the pipe C. The lighter grains flow
over and around the lip D, while the heavier equivalents drop and pass
away through the outlet nozzle E. Suitable dimensions for this kind of
separator are—top diameter of inverted portion of cone, 20 inches; opening at
CHAP. IV.]
SLIME JIGGING MACHINES.
757
top, 4 contracting to 3 inches; annular width between outer case and inner
inverted cone, 1 inch; diameter of chamber at bottom, 12 inches; depth,
6 inches; diameter of nozzle of outlet pipe, 1 inch; diameter of inlet pipe C,
2 inches; head of water, 6 feet. The outside height of the cone is 36 inches,
extreme diameter 25 inches.
(F.) Figging Machines.-The separation of substances of different
densities in water by means of a pulsating movement is founded on the
circumstance that if two bodies of equal volume and of distinct specific
gravity be dropped at the same instant from one and the same height in a
column of water, the one of greater weight will increasingly leave the other
and arrive at the bottom first. In ordinary and continuous jigging-machines
the column of water is too shallow to allow of any appreciable separation of
one grain from another by simply dropping the grains together, but the
desired result is accomplished by subjecting such grains to a series of upward
and falling (pulsating) movements. In the hand-sieve and brake-jigging
apparatus the light and worthless particles (waste), as well as the dredge
and ore, are removed by means of a "limp," but in the mechanical jigger
these products are continuously obtained by the flowing action of water
introduced either above or below the pistons or sieves. The art of jigging
is known to have been practised in the mines of Bohemia in 1519, and
Agricola gives numerous representations of hand-jiggers used in the Saxon
Erzgeberge in 1600 to 1620.
In order to concentrate stuff resulting from the reduction of lead, blende,
or copper ore, coarse as well as fine sand jiggers are necessary; the former
should be placed in connection with sizing trommels, the latter with trom-
mels or classifiers. In the coarse-sand jigger, stuff 10-771-5; 5-3; 3—2
10–7
millimetre size is often enriched on a plate the holes of which are of less dia-
meter than the grains; while in fine-sand jigger, sand 2--14; 14—2; 4−1; 1
millimetre size is separated by the use of a bed of coarse-grained ore, sup-
ported either on a perforated plate or wire grid, with openings larger than the
grains to be collected.
For the purpose of effecting a good separation of ore from its gangue it
is necessary to give great attention to the length of plunger stroke, number
of strokes per minute, and volume of water flowing into the jigger. Every
distinct class of vein stuff will necessitate the observance of some special
condition, so that no absolute directions can be given. The practice is to
increase the speed, shorten the stroke, and lessen the thickness of bed with
the decreasing size of grains to be treated. For coarse-sand jiggers the
speed may be from 60 to 75 strokes per minute, while the water required
will be from 9 to 15 gallons per machine per minute. In fine-sand jiggers
the speed will vary from 90 to 150 strokes per minute, and the water from
10 to 15 gallons per minute. In slime jiggers from 150 to 300 strokes per
minute are made. The approximate length of stroke required for stuff
ranging in grain size from ten to one-sixth of a millimetre may be ascertained
from the following figures :—
Size of stuff 10 to millimetre .
Approximate length of stroke in inches.
Strokes of piston or plunger per minute.
10—71; 71—5; 5—31; 31—2; 2—11; 11—2; 4−); }−)-
4
HA
+
14
2호
​2/1/1
21 I
1
I
60-75
100
110 150-300
3 C 2
758
[BOOK III.
PRACTICAL MINING.
The number of sieve compartments in a jigger must depend in a great
measure upon the quality and composition of the stuff to be jigged. In cases
where only one ore is associated with the gangue a jigger 6 feet long will
generally be sufficient; but when two or three ores are associated together
with several varieties of veinstone a greater length will be found advisable.
In enriching tin stuff or other valuable products a considerable length of
jigging sieve might be advantageously employed.
The motion given to fine-sand piston jiggers need not be a variable one;
in fact a differential movement is of no advantage in a quick, short stroke.
In many dressing works the piston is reciprocated by means of eccentrics,
in others by a rocking and counter shaft, while a third movement is
produced by a revolving disc. Each device usually includes a means for
varying the length of the piston stroke. The gear for driving a group of
jiggers should suit the circumstances under which the latter must be worked.
If the machines are to stand within a closed building belts may be employed,
but if exposed to weather common shafting and wheel gearing will be
preferable.
During the earlier use of continuous jiggers perforated plates were
considered necessary, but experience has shown that wire-wove sieves offer
the advantage of greater waterway and less resistance to the movement of
the piston. For discharging the stuff from the collecting-boxes many
methods are employed. Conical valves are much in use, but slides, Fig. 215,
and plugs handled from the outside are equally effective. To adjust the
thickness of sand on the ore beds in cascade sieves slides are occasionally
fitted to the dividing bridges.
In fixing and working continuous jiggers the following points should be
observed:-
Fixing.-Fix the jigger so that the sieve bottoms may be nearly level.
Sizing.-Size or classify the sand, and thoroughly free it from slime
before passing it to the jigging-sieves.
Sieves.-Sieve bottoms may be of perforated plate or wire-work.
Openings in sieve bottom for sand, to 1 millimetre grain size, must be
greater than the grain dimensions of the stuff to be treated.
Beds.-Ore grains composing the beds must be larger than the openings
in the sieve bottoms. Thickness of beds must depend upon size and richness
of stuff to be jigged.
Hand Figging Sieve.-This sieve is formed of a hoop of oak 18 to 20 inches
diameter, inch thick, and 6 inches deep, while the bottom usually consists
of a screen of copper or iron wire. Sometimes, however, a perforated
copper plate is employed, when the sieve is termed a "copper bottom."
The sieve charged with a thin bed of ore and orey stuff is placed in a cistern
or tub of water and vigorously jerked until the sterile veinstone is separated
from the orey mixture. The waste is then removed with a sheet-iron
scraper, and the enriched ore is obtained.
Dillueing Sicve.-This sieve, either made with a horse-hair or canvas
bottom, is chiefly used for effecting the final removal of any waste which
may be present with the ore.
Brake Figger. The brake jigger consists of a trough or "hutch" through
which flows a small stream of water. Over the centre of the hutch is suspended
CHAP. XV.]
CONTINUOUS SAND JIGGER.
759
a rectangular-shaped sieve, having about 25 holes per square inch, upon which
is spread a bed of
coarse ore about 2
inch thick. The stuff
to be jigged is placed
upon the bed, when
the sieve is lowered
into the water by a
lever, to which a jerk-
ing motion is given
by the hand for two
or three minutes. A
connecting-rod at the
back end of the lever
passes through an
eye in the end of an
upper lever which
carries the sieve, and
which connecting-
rod has a stop fixed
upon it both above
and below the end of
the lever. Between
these stops there is
a certain amount of
play for limiting the
range of the jerking
movement. On jerk-
ing the hand-leverup
and down the heavier
pieces of ore settle
to the bottom of the
sieve. When the stuff
has been sufficiently
jigged the sieve is
raised out of the
water, and the light
particles on the sur-
face, which contain
little if any ore, are
skimmed off and
thrown away, while
the middle partis laid
aside for further treat-
ment. The" bottom,'
comprising best ore
A
C
B
R
A
D
D
·;E:·B.、;B, N F; A B.." B、:
H
S
Fig. 212.
as well as the smaller particles which have fallen through the sieve and into
the hutch, are usually sufficiently rich for the smelting furnace.
Coarse and Fine Sand Continuous Jigger.-Fig. 212 shows a continuous.
760
[BOOK III.
PRACTICAL MINING.
jigger, which is successfully applied to the enrichment of both coarse and fine
sand. Instead of separate sieves placed one below another, one long and
slightly inclined sieve is employed. This sieve, supported on a wooden grid,
is covered with a second grid of similar construction in the compartments of
which the bed is lodged.
Underneath the sieve the ore and dredge receptacles are placed, and at
the end of the hutch is a waste-box fitted with a launder for the escape of the
water. The bottom edge of this launder is from 2 to 3 inches above the
level of the sand, supposed to be in the jigger. The jigging or separation of
the stuff is consequently performed under water, and any fine slime which
the stuff may contain floats and leaves the grains of which the stuff is
composed free to separate, fall, and arrange themselves according to their
respective densities.
A jigger 20 feet long provided with a sieve 42 inches wide will despatch
approximately-
Stuff composed of grains 3 to 5 millimetres diameter, 5 tons per hour.
""
""
2 ,, 3
3
""
A, driving gear; B, adjustable eccentric piston-rods; C, frame work; D,
sieve compartment; E, piston compartment; F, ragging frame; G, grid
frame supporting sieve; HH' H" H", ore-boxes; J, waste-box; K, plug for
P
S
discharging waste-box;
L, feed hopper; M, slide
for adjusting rate of feed;
N, wire-work bottom; 0,
hole in launder; P, partly
covered with a loose slip
of iron for admitting
water to jigger; R, ore-
boxes; S, waste waggon;
T, plug-holes for dis-
charging ore from boxes;
H H′ H" H"",-R', launder
for taking off the over-
flow of water from the
ore-boxes R.
Argall's Figger.—The
piston in this jigger,
placed between two
hutches, is in free com-
munication with two
sieves, s S, Fig. 213.
Two sizes of ores may be
jigged at the same time,
i.e. through No. 53 Corn-
ish gauge, on one side of
the piston, and through
No. 25 on the other side-P, piston; S S, sieves; D D, discharge openings. The
hutch is built in and supported by a frame of wood, to which it is securely
Fig. 213.

CHAP. IV.]
COLLOM'S TAPPET JIGGER.
761
bolted. This frame extends above the hutch and carries the eccentric shaft
and gear.
This machine, with a "four-hole" sieve, and a speed of a hundred and
fifty revolutions per minute, will jig from 5 to 6 tons of coarse-grained stuff
per hour. The pistons are hung to eccentrics.
Gear is fixed to carry off the dredge as it accumulates, while similar gear
is attached to keep the bed at a constant level. The waste passes from the
end of the machine into a waggon, while the concentrated ore is continuously
discharged from the hutch.
The jigger, Fig. 214, shows the method of constructing these machines in
Fig. 214.
wood and of mounting the driving gear on a wooden frame. The machine
includes three rectangular-shaped piston and three cascade-sieve bottoms.
Shifting eccentrics for varying the length of stroke in the pistons and a
fly-wheel to secure regularity of motion are employed. The concentrated
ore is drawn from the ore chambers on lifting the slides by means of the
respective hand levers.
Collom's Figger.-This may be designated a tappet jigger, since the
pulsating action is produced by two pistons, each rod of which is struck
alternately by the "tap" of a rocker, and raised by a spiral spring around
the piston-rod, which spring brings the piston up against an adjustable stop.
The length of stroke given to the piston varies from half an inch to one inch,
while the apparatus may be speeded so as to jig stuff of different degrees of
fineness. The rocker is, however, usually worked by a crank making about
120 revolutions per minute. The space under each piston is in communica-
762
[BOOK III.
PRACTICAL MINING.
tion with one of a pair of hutches, F, Fig. 215. On the top of each hutch is
fixed a fine sieve of brass wire, C, upon which is a bed of coarse ore about
inch thick. The stuff to be jigged, supplied through a launder, Z, with a
stream of water, is delivered upon one end of the sieve through a distributing
grate, the sieve C is set with a slight fall towards the opposite end. The
hutches are kept constantly filled with a supply of clear water with a pressure
of 2 feet of head or upwards by the pipe between the two launders zz. There
is also a constant overflow of water from the lower end of the sieves, carrying
away the lighter stuff that is separated by the jigging process. The tappet
action of the pistons gives a sharp quick motion to the water under the
sieves, driving it up and through them, producing the same effect in sepa-
rating the stuff upon the sieve as in the ordinary jigging-machines where the
P
K
F
MIL
Z
z
Z
JRIMBAULT
K
Fig. 215.
sieve itself is jerked up and down in water. The lighter particles are thus
lifted and gradually carried off in the stream of water flowing over the sieve,
leaving the heavier and richer stuff to settle gradually through the sieve into
the hutch, from which it either passes off continuously through a regulating
hole at bottom, K J, or is discharged at intervals if the supply of water is
scarce. In order to prevent accumulation upon the sieves of stuff which may
be too light to pass through the bedding, yet too heavy to be carried over
the lips of the hutches by the overflowing stream of water, “ragging gear”
is in some cases provided, consisting of a row of holes closed by taper plugs
fitting into conical seatings; the height of the plugs is adjusted by thumb-
screws, P, so as to regulate the area of the openings according to the
CHAP. IV]
SLIME OR BUDDLE JIGGER.
763
quantity of stuff to be got rid of, which never amounts to much; this falls
into a compartment, V, and passes out through a hole at bottom. A second
jigging-machine is fixed immediately in the front of the first, at a few
inches lower level, by which the overflow from the first, by means of the
shoot z, is received, and jigged a second time in a similar manner.
Slime or Buddle Figger.This jigger is taking the place of the round
buddle in various dressing works, the piston of which makes from 300 to
500 strokes per minute. The construction of the apparatus is shown in
Fig. 216. The stuff is introduced to a circular distributing-table, s, by means
of pipes, bb. From this distributing-table the slime falls into an annular
launder, vr, from whence it drops through opening upon the head of an
annular sieve. It is then jigged, the concentrated portion passes through the
S
wing ahme
O
S
Fig. 216.
bed in the sieve into the cistern T T, while the waste flows from the outer edge
of the sieve into an annular launder outside of the cistern. From the cistern
T T the concentrated ore is discharged through gas piping into boxes s s.
Clear water is supplied to the cistern T T immediately under the piston, and its
flow, indicated by the arrows, is uniformly distributed to the bottom of the
annular sieve. The holes in the copper sieve are 1 millimetre diameter,
while the bed on the sieve itself is composed of large grains of ore inch
diameter and 3 inches thick. For slime scarcely of a "sandy feel" the
piston-stroke should be about inch, and the number of strokes not less
than 300 per minute. The quantity of clear water requisite per minute is
about 18 gallons. The slime sent to this buddle should be first classified into
equivalents. The working capacity of a buddle jigger is nearly double that
of a round buddle 25 feet diameter, while the waste from the former is
1
764
[BOOK III.
PRACTICAL MINING.
much poorer in metallic ore than that obtained from the latter apparatus.
By arranging several of these jiggers one below the other, each of a lesser
diameter, slimes consisting of sulphide of lead, blende, mundic, and vein
stuff may be separated from each other and satisfactorily concentrated. The
slime jigger illustrated has the following dimensions :—
Outside diameter of cistern, 9 feet; diameter of piston, 3 feet; height
of cistern, 4 feet; fall of sieve, 4 inches.
(G.) Buddles and Tables.-It has already been observed, in reference to
continuous jigging machinery, that if two spheres of equal volume but of
different densities drop together from the same height in a column of water,
the heavier of the two will arrive at the bottom first. In this instance,
the density of each of the spheres is only opposed by the resistance offered
to its sectional area, viz. by the water through which the sphere is falling.
If, however, two spheres of different densities have an equal velocity of
fall in water (equivalents), the diameter or sectional area of the lighter will
be greater than that of the heavier sphere. Now if the two spheres be placed
side by side on a perfectly flat table no movement will occur; but if a slight
stream of water be applied to their surfaces, the one having the larger
diameter or greater surface (the lighter sphere) will be impelled more rapidly
and separate from the other (the heavier sphere), and if the table be slightly
inclined, the rate of movement of these several spheres of different diameters
D
D
B
P
B
A
will be accelerated.
To these principles
the separation on
buddles or tables of
metalliferous grains
from gangue having
an equivalent rate of
fall in water must be
referred.
Hand Buddle.
This buddle usually
consists of a wooden
box, Fig. 217, D,
about 8 feet in length,
Fig. 217.
3 feet wide, and from
2 to 2 feet deep, sunk
in the ground, and having an inclination of about 2 feet in its whole length. At
the head of this box a distributing-board, C, is placed, which is in communica-
tion with the trough B, and a water launder A. The stuff is thrown into the
trough B, when it is stirred by the buddler's assistant. The fine slime then
passes through a perforated plate to the distributing-board C, and from
thence in a thin and uniform stream into the buddle D, when the buddler care-
fully and continually sweeps the slime and water across the buddle and some-
what against the direction of the current, with the view of freeing the grains
of tin from any viscid matter which may accompany them, and depositing
them at the head of the buddle. In the tail-board at the lower end of the
buddle is a vertical row of holes a few inches apart, through which the surplus
CHAP. IV.]
BUDDLING APPARATUS.
765
water flows, and which holes one after the other are stopped up with plugs
as the stuff rises in the box. About 9 inches in length of water is kept
between the stuff and tail-board, with the view of preventing the escape of
any valuable stuff through the holes. Four-and-a-half buddlesful are generally
finished by two boys in ten hours. The buddle when filled is arbitrarily
divided perpendicularly into four parts-the "head,” the "fore middle head,”
the "middle head," and the "tail." The head, which generally occupies
about one-third of the buddle, is then re-buddled and divided into four parts
as before, the head being tossed and thereby rendered fit for the smelting
furnace.
The Knife or Impeller Buddlc.—About the end of the year 1845 the agents
of the Lisburne mines, Cardiganshire, invented a knife buddle which is fully
described in "Records of
Mining and Metallurgy," by
Phillips and Darlington.
This machine consisted of
an inclined table and a re-
ciprocatory frame carrying
fifteen knives. The knife-
frame made fifteen strokes
per minute, and washed 40
tons of stuff per ten hours,
which stuff yielded 12 tons.
of best, 4 tons of second
class ore, and 24 tons of
waste, which contained 2 per
cent. of ore. Later, Captain
Thomas
Ball, connected
with the
Goginan
Goginan lead
mines, Cardiganshire,
mounted the knives on a
trommel frame, which is now
known as the "Impeller
Buddle." It consists of a
cylindrical frame, 9 feet
long and 6 feet diameter
Hi
B
T
Fig. 218.
C
F
F
over all, rotating on an horizontal axis, and carrying a series of scrapers
or knife-blades arranged in spiral lines round its circumference, which
revolve close to a cylindrical casing lined with sheet-iron, but without
touching it. The casing forming the bottom of the buddle extends rather
less than one quarter round the circumference of the revolving frame as
shown in Fig. 218. The stuff is supplied at one end of the buddle from
the hopper A, and is made to traverse gradually along the whole length to
the other end, F, by the propelling action of the revolving knives, which are
fixed obliquely and follow one another in spiral lines round the cylindrical
frame. A gentle stream of clear water from the launder D flows down over
the whole curved surface of the bottom of the buddle, and the minerals are
gradually propelled to the farther end, where they drop over the edge into
766
[BOOK III.
PRACTICAL MINING.
the receptacle F. The machine is driven at about 20 revolutions a minute,
giving the knife-blades a speed of about 370 feet a minute. The action of this
machine is found to be very perfect, the whole of the stuff being continually
turned over by the knife-blades and pushed upwards against the descending
stream of water, which washes out the lighter particles; the result is an
unusually complete separation of coarse-grained tin ore in a single operation
with only a small proportion of loss in the waste. The contents of the
second waste hutch, C, are so poor as not to pay for any further dressing,
while the waste in the first hutch, B, containing a small proportion of slime
tin, is passed through the buddle a second time.
The quantity of stuff treated at the Lisburne mines, by a single machine,
was 2 tons per hour; the stuff buddled contained about 15 per cent. of lead,
and was concentrated to afford 50 per cent. of that metal. By repeating the
concentration the 50 per cent. stuff was raised to afford 75 per cent. of metallic
lead. The stuff dressed included quartz, blende, carbonate of lime, Clay-
Slate, and lead ore.
This form of buddle may be regarded as a valuable concentrator of
heavy ore, associated with a light gangue such as galena and carbonate of
Fig. 219.
LAKONA UNATA
lime, or of coarse-grained oxide of tin mixed with fine-grained quartzose
sand.
I
Centre-head Buddle.-This buddle, Fig. 219, known as the convex or
centre-head buddle, is about 22 feet diameter, and from 1 to 1 foot deep at
the circumference, with a raised centre 10 feet diameter, and a floor falling
towards the outer circle at a slope of about i in 30 for a length of 6 feet. The
stuff is brought to the centre of the buddle in launders, into which a constant
stream of water flows; and it is distributed upon the raised centre from a
revolving pan shown in plan, Fig. 221, carrying a number of spouts, so as to
spread the liquid stream very uniformly in a thin film, which flows gradually
outwards over the sloping floor to the circumference, Figs. 220 and 221.
In its passage down the slope the material held in suspension by the water
is gradually deposited according to its specific gravity, and the ore being the
heaviest is the first thrown down, and is consequently in greatest proportion
towards the centre of the buddle. The outflow for the waste and slime from

CHAP. IV.]
CONVEX AND CONCAVE BUDDLES.
767
the circumference of the buddle is regulated by a wooden partition perforated
with horizontal rows of holes, which are successively plugged up from the
bottom as the height of the deposit in the buddle rises. To facilitate the
uniform spreading of the stuff over the floor of the buddle, and prevent the
formation of gutters or channels in the deposit, rollers attached to arms are
employed, from each of which is suspended a sweep consisting of a brush
or small piece of cloth, which being drawn over the surface of the deposit
keep it to an even surface throughout. The distributing spouts and sweeps
are driven at about 5 or 6 revolutions per minute.
As the deposit accumulates in the buddle, the sweeps are successively
Fig. 220.
Fig. 221.
raised to a corresponding extent, and the process is thus continued until the
whole buddle is filled to the top of the centre cone, which usually takes about
ten hours. The contents are then divided into three concentric portions, each
about a third of the whole breadth, called the head, middle, and tail.
In tin dressing, the head or portion nearest the centre contains about 70
per cent. of all the tin in the stuff supplied to the buddle, the middle some
20 per cent., while the tail or portion next the circumference contains only
traces of oxide of tin.
Concave Buddle.-The heads from several round buddles are usually
thrown into a trough or launder, into which a stream of clear water flows
of sufficient volume to convey the stuff to concave buddles. Fig. 222
shows Borlase's concave buddle in elevation and plan with a mechanical
arrangement for adjusting the level of the central outflow by using a ring H
that slides upon the centre vertical shaft. By this means the height of the
768
[BOOK III.
PRACTICAL MINING.
outflow is adjusted more gradually and uniformly than by the plugged holes
in the ordinary buddles, and there is less liability to waste by guttering;
the sliding-ring H is raised by hand by the rod and lever L, provided with
N
N
P
D
D
Fig. 222.
adjusting fly-nuts N, and the
arms of the sweeps D, being
supported upon the rising
ring, are kept at the proper
height by the same adjust-
ment; the stuff is introduced
into the box M, and prepared
for the buddle by means of
the revolving agitator; it
then passes through a per-
forated plate N, down the
launder to a central box, from
whence it is distributed to a
circular ledge of the buddle
by six revolving spouts, P,
from which it flows uniformly
over the conical floor, falling
at a slope of about 1 in 12,
towards the centre H. The
greatest proportion of the ore
is deposited round the cir-
cumference of the floor, while
the slime and waste flow over
the top of the rising ring into
the well H.
Ring Buddle.-Although the bottom or table part of a centre-head buddle
is uniformly laid at a given angle, yet as soon as the enrichment of the stuff
occurs, this angle in the stuff itself often increases to a material and unsatis-
b
Fig. 223.
factory extent, especially if the stuff happens to be largely composed of
heavy ore and a light waste.
To neutralise this drawback a movable ring is sometimes placed outside
the table of a centre-head buddle. Fig. 223 shows a ring applied to a centre-

CHAP. IV.]
THE RAGGING DEAD FRAME.
769
head buddle-a, ring; b b, side screws for raising or lowering the ring as
may be required.
B
1&K
Borlase's inclined buddle consists of a slowly revolving annular table,
24 feet diameter and 6 feet wide, placed at an inclination at 1 in 12 from an
horizontal line (Fig. 224). A is the table or frame, which is fed from the
distributors C C C, with the ore to be treated, which is brought through the
launder B. As the ore falls
on the table it is acted on
by a gentle stream of clean
water from D, which washes
off the matrix and earthy
matter, the richer tin re-
maining on the outer periph-
ery, the poorer on the inner,
and the waste flowing from
the inside of the circular
frame at E E E. As the
table revolves, making one
turn in three minutes, and
the lower side is attained,
the ore on it is washed off
by jets of water from the
pipes H H, the richer, or
crop, into launder F, the
poorer into G, from whence
each is conveyed away
through the launders I and
K respectively. The con-
stantly varying inclination
of the table, which at the
receiving side runs from the
E
Fig. 224.
circumference to the centre, and at the washing-off side from the centre to
the circumference, enables the workman to wash off the cleansed material
at any point desirable. This point is found by experiment to be within
21 inches from the edge.
The advantages claimed for this machine are its great simplicity, the
saving of nine-tenths of the ore at the first washing, and the saving of much
labour of dressing, while the waste will not pay for retreatment.
Dead Frame.-In Fig. 225 is shown a self-acting "ragging" dead frame
used on the Red River, Redruth. The bed of this table, 6 feet long and 6 feet
wide, is set at a grade of 1 inch to the running foot. The slimes are
delivered to the table by means of a head board, and in passing over its
surface a portion of the tin ore present is deposited, which is washed every few
minutes into a launder, set at the foot of the table by the canting or falling
over of the V launder set at the head of the table, which launder is filled
with water.
It will be observed that the canting V launder is connected by means
of a long arm, with a lap shown in the figure covering the tin stuff launder
770
[BOOK III.
PRACTICAL MINING.
set at the foot of the table. This lap is opened by the rotating fall of the
V launder, and is almost immediately closed by the return of this V launder
to its normal position. The time of filling the V launder is governed by the
diameter of the hole in the water launder, fixed just above the former. In
the fine slime tin dressing in operation on the Red River two other frames
are employed differing in their dimensions. In the "second or doubling
い
​O
Fig. 225.
frame" the bed is 8 feet long, 6 feet wide, with a grade of 2 inches in a
lineal foot. This frame, instead of being automatic, is worked by hand. It
is also fitted with two launders at the head for delivering to the table clear
or slime water as may be required. The "cleaning frame" differs from the
second frame in the following details.
Instead of one bed 8' 0" x 6' o" there are two beds each 6′ o" square
separated by a launder and lap, so that the stuff, after being treated on the
CHAP. IV.]
CALCINING APPARATUS.
771
first or uppermost bed, runs over the lap on to the second bed; hence the
total length is 12' 0" exclusive of the lap.
The following particulars relate to the dead frames formerly in use at
Great Wheal Vor. Number of heads of stamps in operation, 48; proportion
of stuff for dead frame obtained from 48 tons of stuff stamped, about 15 tons;
number of ragging frame, 40; number of doubling frames required to treat
concentrates from 40 ragging frames, 28; number of trebling frames to treat
concentrates from 28 doubling frames, 4; labour required, one girl to 14
frames, or from five to six girls for the whole series of frames, also one boy
shovelling stuff to supply the 28 doubling frames. The frames were made of
American deal plank, 1 inch. The faces of the frames were cleaned when
in work with a hempen swab once a week. The fall of the ragging frame
was 1 inch to a lineal foot. The diameter of the hole, which was lined
with an iron thimble for admitting water to head board of table, was of an
inch. The diameter of hole for delivering water to V-shaped launder or
washing-trough, 3 inch.
3
1
Brunton's Concentrator.-This apparatus is well adapted for effecting the
concentration of fine slime ore. The following particulars relate to tables
for the enrichment of lead slimes:
Length of table
Width
Speed of cloth
Length of blow given to table
Number of strokes.
Quantity of water required
Quantity of stuff worked per 12 hours per table
Richness of stuff
Percentage of concentrates obtained
Number of hands required
Number of revolutions of feed apparatus
Angle or fall of table
Number of revolutions of feed apparatus per
minute
Number of holes per square inch in stamps
grate, through which stuff is passed for con-
centration on table
16 feet.
6
3 revolutions per minute.
11—13 inch.
75 per minnte.
12 gallons per minute on the average; the
richer the stuff, the less water required.
200 cubic feet.
4 per cent. of lead on the average.
40 cubic feet per 12 hours.
5 boys to 2 tables.
9 per minute.
9 inches in 16 feet; the richer the stuff, the
more inclined must be the table.
9.
•
72 holes in a square inch.
Ore enriched from 4 to 10 per cent. by passing once over the table. One millimetre is the average
size of the stuff treated on these tables.
(H.) Calciners.-For the purpose of getting rid of arsenic, sulphur, and other
volatile impurities sometimes associated with oxide of tin and altering the
relative densities of these minerals, calcination is resorted to. This opera-
tion is in some mines effected by means of an ordinary reverberatory furnace,
in others by the well-known Brunton revolving furnace, or by the rotary
furnace devised by Robert Oxland, of Plymouth, and the late John Hocking,
of Redruth. Brunton's, the older mechanical furnace, is illustrated in Taylor's
"Records of Mining," published in 1829. This furnace consists of an horizontal
revolving table about 12 feet diameter, and of a circular shell and dome.
The table, slightly conical, slopes from the centre downwards to the circum-
ference. The tin stuff, delivered to the centre of the table through a hopper,
is exposed to a flame passing through the furnace, and is continually stirred
by a set of stirrers fixed in the dome, while the table makes from 4 to 6
3 D
772
[BOOK III.
PRACTICAL MINING.
•
revolutions per hour. The stirrers are set obliquely to the line of rotation,
and gradually shift the stuff from the centre to the circumference of the table,
when it falls into a chamber beneath.
Fig. 226 shows Oxland and Hocking's calciner as adopted at several
mines in Cornwall. It consists of a long wrought-iron cylinder, A,
lined with firebrick, 3 feet inside diameter and 32 feet long, placed at an
inclination of 1 in 16 to 1 in 24, according to the nature of the stuff to be
treated, and supported upon carrier wheels, upon which it revolves, making
6 to 8 revolutions per hour. The tin stuff or "whits" supplied to the
higher end of the cylinder through a hopper fitted with a feeding screw, B,
gradually traverses the length of the cylinder to the lower end, when the stuff
falls into a chamber, D, from which it is removed for further treatment. The
heating furnace, C, opens into the lower end of the cylinder, and the volatilised
arsenic and sulphur, &c., are carried off by a flue, F, from the upper end; this
flue is extended to a considerable distance and divided by baffle walls into a
succession of chambers, in which the arsenic is deposited and periodically
E
E
E
Fig. 226.
collected. The time taken for the stuff to pass through the calciner is from
3 to 6 hours. The firebrick lining of the calciner is constructed with 4
longitudinal ribs, H, projecting internally as in a mortar mill, and extend-
ing two-thirds of the length from the lower end. In the revolution of
the calciner these ribs have the effect of continuously shifting the stuff
and exposing the whole of it to the heat. In this calciner the stuff, being
supplied at the upper end farthest from the heating furnace, is exposed
first to the lowest heat and afterwards to a gradually increasing heat as it
works its way along to the hotter end of the calciner; by this means the
most advantageous effect is obtained from the fuel consumed in the furnace.
At Wheal Basset the calcining cylinder, 28 feet long and 4 feet diameter,
is set inclined towards the fireplace at 1 in 16. The cylinder makes 4 revo-
lutions per hour, and calcines 7 tons of whits in 24 hours, with a consumption
of from 17 to 18 cwts. of coal. The labour charges amount to £7 per
month. Once in six years the cylinder requires to be relined with firebrick.
At Wheal Polrose the whits consisted of oxide of tin, iron, and copper
pyrites. The diameter of the bed of a Brunton's calciner was 12 feet;
number of revolutions per hour, 5; weight of tin whits calcined per day of 24
hours, 6 to 7 tons; depth of tin whits, 3 to 4 inches; reduction in weight of
tin whits after roasting, 10 per cent.; number of tons of roasted tin whits
CHAP. IV.]
I
HUMID CHEMICAL PROCESSES.
773
required to make 1 ton of black tin, three; weight of coal consumed per ton of
whits, 56 lbs. The calciner was driven by means of a water-wheel 5 feet
diameter and 12 inches wide. A pinion 9 inches diameter on the water-
wheel shaft was geared into a spur-wheel 33 inches diameter.
Various calciners would probably be found efficient for the calcination
of tin-whits, such as the Hasenclever, Gerstenhofer, Livermore, and the
O'Hara furnace.
(J.) Humid Processes.-The process of extracting "vitriall or coppris" from
burnt ores was evidently practised in this country by the Germans in the
time of Elizabeth. In 1582 an offer was made to Sir Francis Walsingham,
Knight, by one Joachim Gaunse, for "making of copper vitriall and coppris
and smelting of copper and leade ures." In article 5 it is stated: "After
copper ure be roasted and redie to smelting (w'ch roste is done in one fire)
then must the vitrall or coppris, or w'ch of them shal be thought moste
mete, be taken from the ure before it come to the smeltinge, first w'ch is done
by letting water passe through the ures, of w'ch water the coppris or vitriall
must be made, and that water doth not onely drawe the vitriall and coppris
from the ure, but also divers other hurtfull humours being by nature enemyes
to the copper, as arsenick, sulphur, antimony, allome, and ironn." From a
letter inserted in the Philosophical Transactions for 1752, it is stated that the
existence of copper, in solution in the water from Ballymurtagh, Wicklow, had
only lately been discovered by accident, but had given rise to extensive
apparatus where 500 tons of iron were at the same time employed to effect
the precipitation of the costlier metal. The mode of operating was very
rude: pits were dug 10 feet long, 4 feet wide, and 8 feet deep, floored with
flags and lined with stones, and the iron bars were laid on rough wooden
beams fixed across from wall to wall. By this mode a ton of the precipitant
obtained from the pits yielded 16 cwts. of the finest copper.
Pryce, in his "Mineralogia Cornubiensis," page 33, observes: "Dr. Rouby,
a curious foreigner, set on foot a manufactory of Roman, or blue, vitriol at
Treleigh, in Redruth, about five-and-twenty years since (1753), which dropped,
only with a loss of £90, by means of some disputes and disagreements
among the persons concerned. It was collected from the waters which were
left from the lotions of black tin after it had been calcined in the burning
house for the discharge of its mundick. The water being strongly impreg-
nated with vitriolic particles after it had been decanted clear from its dregs,
was kept constantly boiling by a gentle fire for seven or eight days in a leaden
boiler, which being evaporated to a pellicle, it was drawn off and set to
crystallise in proper vessels. The time for crystallization was generally
three to five days, according to the different degrees of the impregnation of
the water, 8 tons of which well saturated with vitriolick particles would
yield a ton of blue vitriol.”
Towards the close of the last century, copper was obtained at Cronebane
and Tigrony, by means similar to those employed at Ballymurtagh in 1752,
only it was usual to add to the strength of the solution by placing in the water
a quantity of poor pyritic ore which had undergone a process of roasting.
The ratio of pure copper to the precipitate powder was only about 6 cwts.
to the ton.
3 D 2
774
[BOOK III.
PRACTICAL MINING.
On the 31st of May, 1838, Duclos patented improvements in the manu-
facture of zinc, copper, and antimony, in which he claimed the mode of
manufacturing copper from copper ores by repeated oxidation of the
sulphurets and dissolution of the sulphates therefrom, precipitating the
metallic copper by iron and the concentration by heat of water containing
copper.
On the 10th of June, 1843, he also obtained a patent for improvements in
the manufacture of lead, tin, tungsten, copper, and zinc.
As oxide of tin (black tin) is almost indifferent to the action of acids, the
treatment of tin stuff for the separation of other metallic oxides is compara-
tively easy. With moderate care, mine tin might be made equal in quality
to stream tin for the production of metal. Considerable money advantage
would therefore accrue to certain tin mines if the black tin were rendered
pure.
In 1842, at the Balleswidden mine, Cornwall, acids were employed by
Duclos in the treatment of tin ore. In the same year, October 20th, 1842, a
patent was obtained by W. Longmaid, having for its object the utilization
of the sulphur in sulphur ores by mixing with them common salt and
roasting the mixture, converting the sulphur into sulphate of soda, the
copper into a soluble chloride, washing out both, leaving oxide of iron, tin,
and earthy matter, from which the oxide of tin could be mechanically sepa-
rated. Longmaid's process in the main was subsequently adopted by
Henderson, and is essentially the one in use by the copper extractors at
Widnes and elsewhere.
When the foreign matter consists almost exclusively of oxide of iron
muriatic acid may be advantageously employed, or when the stuff after
calcination contains copper, dilute sulphuric acid may be used as the solvent,
the sulphate of copper washed out, and the copper precipitated in the metallic
state with iron or as an oxide with soda ash. About the year 1844 Robert
Oxland, of Plymouth, successfully introduced at Drake Walls his process
for treating tin stuff associated with wolfram.
At East Pool, near Redruth, some portions of the tinstone contains a
considerable quantity of wolfram. The tinstone is reduced and dressed in
the ordinary way, calcined to get rid of arsenic and sulphur, subsequently
buddled and tossed, and then mixed with soda ash in the proportion of 50
per cent. of the quantity of wolfram present, and placed in a heating furnace.
The whole is then subjected to a great heat in a furnace for about four hours,
occasionally stirred to decompose the wolfram and to form tungstate of soda,
when the charge is drawn and thrown into a lixiviating tank. The solution of
soda is drawn off from these tanks into evaporating pans until dry tungstate
of soda is obtained, and in turn tungstic acid, by treating tungstate of soda
with hydrochloric acid. The oxide of iron and manganese being insoluble
are readily separated in the subsequent process of dressing the lixiviated stuff.
In the furnace the stuff sometimes bakes into hard masses, which must be
broken up, crushed or pulverised, and be redressed before preparing it for
market.
About the year 1857 the late W. Henderson employed at Alderley Edge,
in Cheshire, hydrochloric acid for the purpose of extracting blue and green
CHAP. IV.]
EXTRACTING COPPER FROM PYRITES.
775
carbonates of copper from a Sandstone found in that district. The appa-
ratus consisted of a series of small stone tanks, each 11 feet long, 8 feet wide,
and 4 feet deep, fitted with a false bottom. Pumps for lifting the acid from
beneath the false bottom of one tank to the top of the next were employed
in order that the whole solvent power of the acid might be utilised, and a
series of ordinary vats were used for precipitating the copper. In eight
years, ending 1872, 95,000 tons of cupreous Sandstone treated at Alderley
Edge by dilute hydrochloric acid afforded 1,444 tons of fine copper, or 1
unit of copper per ton of Sandstone treated.
In 1875 a process was introduced by Mr. Fred. J. King for obtaining copper
and zinc from the poor carbonate and oxide of these metals by means of the
solvent power of ammonia or carbonate of ammonia, the ammonia being
recovered and used for a fresh attack. The operation was conducted in close
vessels of simple construction, and the ammonia recovered from the solution
after it had done its work by means of heat applied to the outside of a vessel
and an exhaust-pump put in connection with the inside, while the metals
were precipitated as an oxide or carbonate of copper. Some carbonate of
copper treated by King's process, affording 3 per cent. of metal, yielded an
oxide which contained 79 per cent. of copper.
Extracting Copper from Burnt Cupreous Pyrites.-About 700,000 tons of
cupreous pyrites, containing 3 to 3 per cent. of copper and 46 units of
sulphur per ton, are annually imported into this country chiefly from Spain
and Portugal. The sulphur is "burnt" for the production of sulphuric acid,
and the residue is roasted with salt for the purpose of converting the copper
present into a chloride. The following is a brief summary of the process.
(1.) The burnt ore, containing on an average 2 to 3 per cent. of sulphur, is
ground between rolls. (2.) A sufficient quantity of unburnt sulphur is added
to the ore to raise the percentage of sulphur to an amount slightly in excess
of the copper present, at the same time a sufficient quantity of salt is added
to convert the copper into a chloride. (3.) The mixture is passed through a
sieve six holes to the lineal inch and then into a roasting furnace having
flues beneath the bed through which the flame passes before coming into
contact with the ore. (4.) The mixture, about three tons charged into the
furnace through a hopper in the arch and spread evenly over the bed to a
depth of 4 to 5 inches, is stirred and rabbled from time to time in order to
expose fresh surfaces to oxidation, the temperature not being allowed to
exceed dull redness. (5.) Hydrochloric acid evolved during the roasting is
conveyed to a condenser from which a weak solution is obtained, and subse-
quently employed in the lixiviation of the roasted ore. (6.) From 6 to 63
hours are necessary for converting the whole of the copper in the ore into a
soluble chloride, when the charge drawn out on to the floor of the furnace-
house is allowed to cool considerably, and then taken to wooden lixiviating
tanks holding 16 tons each fitted with false bottoms, upon which is a layer
of cinder serving as a filter. (7.) The hot chloridised ore is washed with hot
water and finally with a little hydrochloric acid; the first or stronger solutions
are then ready for precipitation by means of metallic iron, the weaker are
run into separate tanks, from whence they are pumped back to serve as
washing water for a fresh lot of furnaced ore. (8.) The copper present in the
776
[BOOK III.
PRACTICAL MINING.
strong solution is precipitated by means of cast or wrought iron immersed
in the solution itself, and if the solution be kept to a boiling-point by means
of steam the precipitation will be completed in about twelve hours. (9.) The
spent liquor, chloride of iron, which is valueless, is syphoned off from the
precipitated copper, and the latter, freed from iron by washing through a
perforated plate, contains when drained and dried from 70 to 75 per cent.
of metal ready for the smelter.
Claudet's Silver Process.-On January 31, 1870, Claudet patented a process
entitled, "Improvements in the Treatment of Cupreous Ores containing
Silver." In many copper-extracting works the silver present in the cupreous
solution, previous to the precipitation of the copper, is extracted by mixing
with the solution a quantity of soluble iodide, usually that of potassium,
sufficient to combine with the silver present. The insoluble iodide of silver
is allowed to subside and the copper solution drawn off into the precipitating
tank. After a considerable quantity of iodide of silver has been collected,
it is well washed to free it from copper, and whilst suspended in water
metallic zinc in thin slips is added and the whole kept boiling by a jet of
steam. The iodide of silver is then decomposed, when metallic silver and
iodide of zinc are produced. The latter solution serves to precipitate a fresh
quantity of silver, while the former when dried is ready for the bullion
smelter.
At the present time cupreous mine-water is usually led through a
series of narrow launders slightly inclined and interrupted at intervals by
deep hutches. The iron placed in the launders is frequently swept with
a broom for the purpose of removing the precipitate and obtaining fresh
surfaces of iron for the deposition of the copper. With cupreous water
(CuO, SO3) and iron as a precipitant the following chemical action takes
place.
CuO, SO3.
FeO, SO3.
Fe
Cu
Sulphate of iron (FeO, SO3) becomes oxidised by exposure to the air
and falls to the bottom as ochre (Fe2, O2). To avoid the expense of brush-
ing the iron deposited in the launders, Captain Isaac Richards devised a
sprinkler, a kind of round buddle, in which he placed scrap iron. The arms
of the buddle, perforated with fine holes, were connected with a tank annular
with the central axis. On filling this tank with cupreous water, it flowed to
the arms, issued through the holes, caused the arms to revolve, and thereby
sprinkled the iron with the liquor, keeping the iron clean in the operation.
The deposit obtained by this method was for every 3 tons of iron converted
into a sulphate 2 tons of copper precipitate, containing 50 per cent. of pure
copper. In other words, 300 units of iron precipitated 100 units of pure
copper.
The ores best fitted for the humid process are poor oxidised ores asso-
ciated with silicious substances, which can only be smelted at a considerable
consumption of fuel, and which would also suffer great loss of metal in the
CHAP. IV.]
MAGNETIC SEPARATING MACHINE.
777
dressing. It is of essential importance that the ores wash well, and do not
contain substances soluble in acids, such as lime or sparry iron ore, and
therefore oxidised ores with insoluble gangue are treated with the greatest
advantages.
(K.) Separation of Magnetic Iron Ore.-In some of our metalliferous mines
ores of two or three distinct kinds are produced from the same lode, which it
is the business of the dresser to separate. When the specific gravity of
each varies considerably the operation is not attended with much difficulty,
but where an ore as blende is associated with spathose iron, iron pyrites,
or copper pyrites-ores of almost similar specific gravity—a perfect separa-
tion is impossible by hydraulic means, and such ores are frequently unsale-
able either from their low percentage of metal, the alloys they produce, or
from the deteriorating effects consequent on smelting one ore with the other.
The latter is especially the case when iron and copper pyrites occur with
blende, the smelter obtaining a hard spelter.
Mr. F. J. King had his attention directed to this subject in a mine where
the ores from the vein stuff consisted of lead, blende, and spathose iron.
The lead was dressed without much difficulty, but owing to the almost
similar specific gravity of the blende and iron these could not be separated,
although the best known methods of sizing and mechanical dressing were
resorted to. This is not surprising when it is known that the specific gravity
of blende is about 4.0 and that of spathic iron 3.85. The blende raised from
this mine being in quantity about three times as much as the lead, it became
essential that the blende should be made marketable. In carrying out
various experiments upon these ores, it was found that the iron, composed
of protoxide of iron and carbonic acid (FeO, CO2), would at a dull red heat
part with its carbonic acid and become a magnetic oxide of iron. In
practice it is necessary that this heating be done without access of air,
or a higher oxide, which is non-magnetic, will be produced.
The treatment adopted is as follows:-
The blende and iron ores fed through a hopper into revolving iron retorts,
heated by a fire beneath, are delivered, when heated to redness, into a close
chamber. The ores thus prepared are carried by an elevator to the magnetic
machine, which consists of four magnetic wheels, the magnets being so
arranged that the whole surface of the wheel is magnetic. The ore falls
upon a band which passes round the wheel. This band is made of any thin
material which allows the magnetic force to pass through it, and the blende,
not being held to the wheel, falls into a shoot and is received into waggons,
while the iron adheres to the wheel and drops into another shoot at a
point where the band is removed from contact with the wheel by means of a
roller.
In the separation of copper or iron pyrites from blende, the treatment is
somewhat similar, but the heating process is more simple, as access of air
during the heating is an advantage. The result of heating pyrites is to
remove a portion of the sulphur, bringing it to the condition of magnetic
pyrites, which occurs as a distinct ore in some mines. Its composition
is represented by FeS2 + 6 FeS, while that of iron pyrites before heating
is FeS2.
778
[BOOK III.
PRACTICAL MINING.
Instead of employing a wheel fitted with permanent magnets, electro-
magnetic wheels may be successfully used. By calcining the ore in an
ordinary flat bottom reverberatory furnace at a temperature of about 1250°
Fah., and subsequently allowing it to pass over a couple of electro-magnetic
machines, a good separation of blende from the magnetic oxide of iron may
be effected. A Gramme machine will be found satisfactory for the purpose
of generating the necessary magnetic current.
(L.) Tossing and Packing.-When most of the foreign matter has been
separated from the tin stuff by successive buddling operations, the tin stuff
is then subject to the process called tossing and packing, which has for its
object getting rid of the finer particles of waste present. The tin stuff is
put into a "kieve" about 3 feet diameter and 2 feet deep, and with an
equal volume of water is continually stirred with a shovel in one direction
until the tin stuff is in a state of suspended motion. After tossing or stirring
the tin stuff undergoes the process called "packing," which consists in
tapping the side of the kieve with a heavy iron bar for a period varying from
a quarter of an hour to an hour; the bar is held vertically with one end
resting on the ground, and with the upper end repeated blows of about 100
per minute are struck by hand against the edge of the kieve. This packing
keeps up a constant gentle vibration among the descending particles and
facilitates the separation of the tin ore, which gradually settles to the bottom
of the kieve. Instead of a hand-worked, a mechanical hammer is employed
at some mines for performing the packing, with the advantage of maintaining
complete regularity in striking the blows for any length of time required.
When the packing is finished, the upper portion of the stuff in the kieve is
skimmed off and rebuddled, and the remainder, now called "whits," is taken
UHU
A
M
Fig. 227.
K
B
M
A
to the burning-house to be calcined. The kieve is completely cleared out
before commencing with a fresh charge.
Fig. 227 shows a tossing, and packing or dolling machine: A, kieve;
CHAP. IV.]
SAMPLING COPPER AND LEAD ORES.
779
B, dolly; C, clutch for throwing dolly in or out of gear; D, packing
hammer; H, cam for lifting lever weight and packing hammer; J, head
of packing hammer; K, lever for throwing packing hammer out of gear;
L, shaft for running dolly and packing hammer; M, bevel wheels. The
diameter of the kieve at the bottom is 34 inches, at top 42 inches, and depth
30 inches.
(M.) Sampling Ores.-The following description of sampling copper ore
in Cornwall in 1778 is taken from Pryce's "Mineralogia Cornubiensis": "A
dressed parcel of ore before the day of sampling is very well mixed by
several men, who turn it over again and again, a person standing on the
top of the pile or parcel, who spreads every shovelful circularly and as
equally as he possibly can, so that in fact it is mixed with great exactness.
This parcel, if less than ten tons, is divided into three doles or piles, if above
ten into four doles or piles, and if ever so many more than nineteen tons
it is divided into six doles, and then it is ultimately ready to be sampled.
Now, when the samplers meet upon the spot according to appointment,
either of them indifferently fixes upon the one-sixth, one-fourth, or one-
third dole of a parcel, according as it is great or small, to take their samplers
from. The miners then cut or part that dole athwart and across down to
the ground, so that it is divided nearly into quarters by these transverse
channels which are cut through it. Then a sampler with a shovel pares down
a little of the ore from all parts of the channels to take as equal and regular
a sample throughout the whole as he can, to the amount of two or three
hundredweight, which is carried to a clean floor or laid on boards, and then
well and regularly mixed in a small heap by itself. Next a sampler cuts
this also into quarters, ordering any two of the opposite or adverse quarters
to be returned to the great dole from whence they were brought. The
remaining half he still mixes and quarters until it is brought to a small
compass or quantity, when it is sifted through a small coarse wire sieve, and
the large stones which cannot pass through the sieve are broken with a
sledge or flat-polled hammer till all will pass through the meshes. After
this he mixes it very curiously three or four times over, and so quarters and
remixes it as before until it is reduced to a small quantity. Lastly, he puts
about a pound or two of it in a small bag, which is a sample of the whole
parcel. Each of his brother-samplers fills his bag likewise in order to assay
or prove its value by fire."
This description of the method of sampling copper ore still remains
correct. Unfortunately, the limited quantity of ore raised has dispensed
with the necessity for monthly sales. The ticketing sales now occur about
once a quarter only.
Lead Ore.-The usual method of sampling ordinary lead ore may be thus
described :-
The ores are divided into four classes: (1) cobbed ore; (2) sieve raggings;
(3) fine raggings; (4) slimes. Each variety of ore is heaped separately
during the month. As the quantity added each day cannot always be of the
same metallic produce, each heap at the end of the month is thoroughly
intermixed by means of shovels. The heap is then flattened and divided
into quarters by two main passages made at right angles to each other, the
780
[BOOK III.
PRACTICAL MINING.
intersection of the passages being at the centre of the heap. Samples of
No. I cobbed, No. 2 sieve raggings, and No. 3 fine raggings are now taken
according to the following rules. From the sides of the passage or wall
of each quarter, as well as from each heap into which the original heap is
subdivided, several shovelfuls of ore are taken, and the whole placed on a
plate of iron 6 feet square, having sides 3 inches high.
The sample is then well mixed and again divided into quarters, mixed
and subdivided if necessary in the same manner as already described, until
one quarter of the pile is reduced to a weight of 25 or 30 lbs. When this is
done, a man turns his back against the sample and the officer in charge
marks the divisions on separate heaps, 1, 2, 3, 4. The officer then calls out
which heap is to be rejected; if "second," then 2 and 4 are rejected, and 1
and 3 constitute the sample. The sample is then taken into the sampling-
house, and by means of a large pestle and mortar reduced to grains not
exceeding one-fifth of an inch in diameter. After passing the reduced ore
through a sieve, it is again divided by quartering the heap until the quantity
is lessened to 5 or 6 lbs. in weight, according to the number of samples
required to be sent to the smelters.
3
This latter quantity (5 or 6 lbs.) is then reduced so as to pass through a
sieve perforated with holes or millimetre in diameter. Should the
cobbed ore sieve or fine raggings be moist through exposure to the rain or
other cause, the samples may be readily dried by placing them in a copper
pan over the fire. A similar method is also observed in dividing, pulverising,
and taking the samples of the slimes. When, however, the sample from the
latter ore is already well mixed, about 6 lbs. is spread upon the bottom of the
iron plate, and from several places a spoonful of ore is taken and put into
a small bag. Each sample from 5 to 6 lbs. in weight is then dried, pulverised,
and passed through a wire or perforated -millimetre-hole sieve. A slip of
paper describing the ore is then put into each of the bags, which bags are
then taken to the office where the process of filling sample cartridges is thus
carried out. 1. Each bag is separately emptied into a copper pan and
again well stirred and mixed. 2. The sample cartridges are now filled and
both ends sealed. 3. On each cartridge, about 7 inches long and 1 inch in
diameter, is endorsed the description and estimated weight of the parcel of
ore, also date of intended sale. The cartridges are simply made of foolscap
paper, one sheet being sufficient for two cartridges. The paper is rolled
on a piece of round wood and the outer edge glued to the cylindrical
surface.
Tin Stone.-The sampling of tinstone is conducted in the following
manner. Assume the parcel to be 20 tons. 1. It is spalled to a suitable
size for the stamping-mill. 2. The spalled pile is turned over and
over by means of shovels so as to mix one portion uniformly with the
other. 3. The "mixed" pile is divided into "doles" or parts, 20 tons, into
say 20 doles. 4. Any one of these 20 doles is selected by the captain
of the mine, weighed, and 10 per cent. of the weight deducted for water
assumed to be contained in the dole. 5. The dole or ton sample is then cut
through the centre for about a foot in width, and from the sides of this
cutting a cubic foot, a little more or less, is gently and carefully taken,
CHAP. IV.]
SAMPLING OF TINSTONE.
781
placed in a "sample box," and removed to the sampling-house. 6. The
sample, broken to a uniform size, to about that of a walnut, is evenly distri-
buted as a thin round layer on the "bruising pan." It is then divided by
cuts through the centre at right angles to each other into four fairly equal
parts, two of which, one at each opposite corner, being thrown aside. This
dividing and rejecting operation is repeated four or five times, until the
quantity is rendered sufficiently small to be semi-pulverised, when the sample
is dried in a flat, low-edged pan over the fire. 7. The grains constituting
the sample are now reduced to a finer state of subdivision, divided and
rejected on the "refining iron," as described in No. 6, until a small bag
constituting the sample for assay is obtained. 8. This sample is now
handed to the "sample trier," who washes it on a "vanning shovel," and
gets rid of most of the waste by a peculiar motion given to the shovel, the
sample trier further pulverising the sample as may be necessary, so as to
obtain a residue consisting chiefly of oxide of tin. 9. This residue or sample,
if associated with iron or arsenical pyrites, is now roasted in a crucible for
a period of twenty or thirty minutes until the sulphur or arsenic present is
completely volatilised. 10. The roasted sample is then vanned, dried over
the fire, and after the application of a powerful magnet for the purpose of
extracting any magnetic particles which may be present, a tolerably pure
oxide of tin is obtained. The value of the parcel of tinstone is then esti-
mated—weight 20 tons, 1 oz. of oxide of tin, equivalent to 1 ton oxide of tin,
market value £50 per ton.
Then-
£50 oo will stand for 1 ounce of oxide of tin.
2 10 O
O 2 I
I dwt.
I grain
Now let it be assumed that the sample in question gave 19 grains
of black tin. 19 by 2s. 1d. will give a value of £1 19s. 7d., or for the
parcel, 20 tons, the sum of £39 11s. 8d. The tools and apparatus
used in the sampling operation are (1) steel ragging sledge, 7 lbs. weight,
6 × 2 × 13
1; (2) steel spalling hammer, 3 lbs. weight, 6 inches long;
(3) sampling or bruising iron, 24 inches square x 24 inches thick; (4) buck-
ing iron, 4 inches square, 8 lbs. weight, convex face, hilt through eye or
loop on top; (5) refining iron, flat, with smooth face; (6) bruising hammer
used on refining iron, flat, 4 inches square, 3 lbs. weight; (7) bruising
hammer used on the vanning shovel, flat, smooth surface at either end,
weight 3 lbs.
The adventurers in various small tin mines in Cornwall, insufficiently
explored to justify the erection of costly dressing machinery, sell their tin-
stone to a class of men known as "bargain buyers." In determining
their offer for tinstone they usually deduct £10 per ton from the market
price, and as the tinstone is commonly reckoned by the barrow, five of which
are supposed to make a ton, the buyers also deduct is. per barrow, or 5s. per
ton, and include both sums under the name "returning charges." Thus, if
the market price for black tin is £50 per ton, the deduction will be (200s. +
5s.) £10 5s., and the net price £49 15s., upon which the value will be esti-
mated. To obtain the actual weight of black tin in a ton of tinstone
782
[BOOK III.
PRACTICAL MINING.
corresponding to the number of grains or dwts. in a sample of 20 dwts.,
recourse is had to the following table :-
Number of
Grains of
Black Tin
Yield of Black Tin per
Ton of Stuff.
Number of
Grains of
Black Tin
Yield of Black Tin per
Ton of Stuff.
in Sample
in Sample
of 20 Dwts.
of 20 Dwts.
Grains dwts. Cwts. qrs. lbs.
ozs.
Grains dwts. Cwts. qrs.
lbs.
Ozs.
123t5o a
I
O
O
O
4
ΙΟ
12
O
2
9
18 O
O
3
14
о
24
О
18
ΙΟ
2
O
23
I
O
9 O
I
14
550
1235O
345
I
о
о
O
о
The sampling of ores is, in many places, mechanically performed. In
Chili and Bolivia, as well as in the principal mines of the desert of Atacania,
a simple and effective apparatus is employed. At the Lebanon mine in
Colorado a mechanical sampler is also advantageously used.
(N.) Dressing Ore Floors.—A site for a dressing-floor should, if possible, in-
clude the following advantages. 1. Ample room for the buildings, machinery,
and waste hillocks. 2. Cheap transport of the vein stuff from the various
shafts. 3. A natural and constant supply of water for jigging, buddling, and
other dressing purposes. 4. A suitable fall of ground for gravitating, as it
were, the stuff from one to another set of dressing-machines. 5. A good fall
and sufficient area of ground for the disposal of the tailings. If the enriching
machinery be of a simple and satisfactory character, such a site will admit
of cheap and ready treatment of the stuff. There need be no lifting of the
orey products for the various mechanical operations which it will have to
undergo, and consequently no necessity for employing inverted wheels, cup-
elevators, or lifts. To run the stone-breakers, crushing-mills, jiggers, and
buddles, shafting, belts, and riggers may be satisfactorily employed, but
in such case the machinery should be placed within covered building.
In many cases, however, a considerable fall of ground and a full supply
of water are not obtainable, and recourse must be had to means for lifting
the stuff and circulating the water.
In Cornwall, Wales, and elsewhere the stuff is frequently lifted from the
floor to the rolls of the crushing-mill and to the pass of the stamps by
means of a short wooden incline-plane, a waggon, chain, drum, clutch, and
friction gear comprising a simple, cheap, and effective apparatus. For
lifting rough vein stuff and coarse sand, cup-elevators are employed, mostly
in the North of England, while slime, partly suspended in water, is passed
from a lower to a higher elevation by a dipper-wheel or an Archimedean
screw. In almost every instance in Cornwall, where the initial supply of
water is insufficient for the various washing processes, it is supplemented as
it were by returning it to the head of the dressing-floors by an ordinary
plunger, which is preferable to a centrifugal or drawing pump. The
machinery to be employed in the enrichment of ore is almost settled by
common consent. For tinstone the reduction commences with the stone-
breaker and stamps, while for copper, lead, and zinc ore hand-cobbing may
CHAP. IV.]
LEAD ORE DRESSING-FLOORS.
783
form the first stage in the operations, but reduction will be performed by the
stone-breaker and the crushing-mill. From the crusher the sand is usually
divided into slimes for buddles and sand for jiggers. In tin-dressing the
jigger is not used, although it might be in many cases with considerable
advantage; the stamped stuff either goes into strips or runs directly to
round buddles and frames. The chief aim to be sought in effecting the
mechanical separation of ore is to limit the number of the dressing-
machines to the character and value of the ore, to shorten the dressing
processes as much as possible, to minimise the loss of ore consequent on divi-
sion and subdivision of the stuff, and to get a product not only suitable for
the smelting furnace, but one which will bring into the coffers of the under-
taking the largest amount of money.
Great Britain contains a considerable number of lead-bearing strata,
enclosing veins of sulphide of lead and argentiferous ore. The former ore is
mostly found in the Mountain Limestone, the latter in the older rocks. The
outcroppings of some veins furnish carbonate, and occasionally stones of
phosphate of lead, but the ore for the smelting furnace is, in nearly all cases,
sulphide of lead. At Alderley Edge a limited quantity of carbonate of lead
exists in a fine-grained Sandstone. Lead veins ramifying throughout the
Limestone frequently contain compact galena and blende, while in Cornwall
they carry the sulphide of lead, silver, copper, zinc, iron, and carbonate of
iron. The veinstone or matrix accompanying lead ore often varies. In
North Wales it consists of carbonate of lime, quartz, and silicious Limestone;
in Derbyshire of carbonate of lime, quartz, and barytes; and in the North of
England of quartz, carbonate of lime, fluor-spar, and barytes. In Devonshire
and Cornwall fluor-spar and quartz frequently accompany the ore.
ratus.
The ores of lead are mined and brought to surface in the usual way,
either by shafts or levels. Compact galena associated with carbonate of
lime, Limestone, or Slate rock may be quickly and cheaply dressed, but the
complex ores adverted to will require both skill and care to separate them
from the matrix, if a heavy loss of the metalliferous portion present is to be
avoided. Blende, carbonate of iron, and copper pyrites, when associated
together, being nearly alike in density, are scarcely separable by hydraulic
means. In some cases these ores are dressed by dynamo-magneto appa-
Formerly a considerable number of enriching operations were
required to separate lead and blende ore intimately mixed with veinstone,
but the use of the stone-breaker, sizing trommel, classifier, and improved
buddle has materially shortened, as well as cheapened, the cost of the dressing
process. The apparatus employed in the dressing of lead ore usually con-
sists of a wash kiln, Fig. 192, or of a washing and dividing trommel; a stone-
breaker, Figs. 193, 194, frequently fitted with a sizing trommel; a crushing-
mill and dividing riddle, Figs. 195, 196; a classifier, Fig. 210; a separating
cone, Fig. 211; a set of sizing trommels; coarse and fine sand jiggers, Fig.
213; a "fine" crushing-mill, or a small battery of stamps; side blow shaking
tables and round buddles, Figs. 220 and 223.
At the wash kiln the stuff is usually separated into two classes, viz.
stones too large to pass through the holes in the washing plate, and stuff
sufficiently small to fall readily through such holes. The former product,
the stones, are reduced in size, and furnish prill, dredge ore, and waste,
784
[BOOK III.
PRACTICAL MINING.
while the latter yields a similar set of products. The prill or pure ore is
carried to the ore-house, the waste to the hillock, while the dredge is
frequently cobbed, furnishing in turn pure ore for the ore-house, dredge for
the stone-breaker or crushing-mill, and waste for the attle-heap. After the
dredge has passed through the stone-breaker it is often divided into-
Roughs which furnish
Smalls which when sized and jigged yield
Pure ore to ore-house.
Dredge to crushing-mill.
Waste to hillock.
Pure ore to ore-house.
Raggings to crushing-mill.
Skimpings to hillock.
The dredge and raggings, after they have passed through the rolls, are
reduced to grain sizes from o to X, the latter (X) representing the diameter
of the holes which may be in the riddle which is set underneath the rolls.
If it be a "five-hole," that is, five holes per lineal inch, each being equal to a
hole five millimetres in diameter, the grain size will range from 0 to 5 mm.
This mixed lot of grains will now pass into a separating cone, the object of
which is to obtain slime sand for the classifier and buddles, and to keep any
fine gritless slime which may be present from passing into the jiggers
along with the coarse sand.
Let it be supposed that the division happens to include on the one hand
gritless slime, and slime sand for buddles, composed of grains varying in
their dimensions from o to 1 mm., and coarse sand for jiggers, comprising
grains 1 to 5 mm. diameter. The latter coming first in the sequence of
dressing will be sized into grains-
1 to 2
mm. and passed to No. 1 jigger
2
""
3 mm.
2
3 "
""
3,5 mm.
""
""
each of which will furnish
Pure ore for ore-house.
Raggings for fine crusher
or stamps.
Waste for hillock.
classified into two or
While the grit slime and slime sand may be
three sets of grains, each of which, enriched on a like number of buddles,
will furnish pure ore for the ore-house, middles for retreatment, and waste
for the hillock. The raggings, after passing through the fine crusher or
stamps, will either run into a trommel to be sized and jigged, or into a
classifier to be classified for enrichment in the buddles.
10
The ores derived from the Cardiganshire and Cornish veins do not
perhaps contain on an average more than 5 per cent. of lead, which must be
dressed to assay from 70 to 75 per cent. of metal. If the loss in tailings
be reckoned at one-half unit of lead per ton of stuff, and the dressed product
yields by assay 75 per cent. of lead, it follows that 16 tons of vein stuff
will be necessary to afford one ton of ore. In 1856 the quantity of lead ore
raised in the United Kingdom was 101,997 tons, which contained 73,129 tons
of lead. In 1881 the total tonnage quantity had fallen to 64,702 tons of ore,
representing 48,587 tons of metallic lead. The argentiferous ores of lead are
obtained chiefly from Cornwall, Cardiganshire, and the Isle of Man.
The production of blende, which was mostly obtained from the lead
veins, was confined to fifty mines distributed throughout the United
Kingdom. For the year 1881 these mines afforded 35,527 tons of ore, which
yielded 14,947 tons of metallic zinc.
1
CHAP. IV.]
COPPER ORE DRESSING-FLOORS.
785
In many Cornish mines the lodes contain both tin and copper ore.
In some instances it has been found that copper mainly formed the shal-
lower and oxide of tin the deeper portions of a lode, as, for example,
at Dolcoath mine; while at Tregembo, near Hayle, sulphide of copper,
arsenical iron pyrites, spots of sulphide of lead, and streaks of oxide of tin
are found more or less aggregated together. The most abundant ore of
copper is copper pyrites, a sulphide of copper and iron, containing, when
strictly pure, 346 per cent. of metallic copper, 30.5 per cent. of iron, and
34'9 per cent. of sulphur. The other principal ores are the red and black
oxides of copper, purple or single sulphide of copper, and blue and green
carbonate of copper. The metallic percentage of each of these ores when in
a state of absolute purity is :-
Copper pyrites
Red oxide of copper
Black
""
Grey copper sulphide.
Purple
(horse-flesh, sulphide)
Green carbonate, malachite
Blue
azurite
34.6
88.8
•
79.8
77.1
70°
•
57.3
•
55°1
None of these ores are very hard, all being readily scratched with a
knife. The vein stuff, consisting of earthy matter and metalliferous ore, is
raised from the levels in skips or kibbles, containing from 10 to 20 cwts.
each. On reaching the surface the stuff is tipped into a waggon and
transported on a tramway laid about 10 feet from the ground, which under-
neath is divided into stalls known as slides. Into these slides the stuff is
tipped from the waggon. Then the dressing process usually commences;
the larger stones are broken up with a sledge hammer called "ragging,” and
if a stone-breaker happens not to be a part of the plant the raggings are
further reduced by spalling hammers to a size not exceeding the gauge
of a ring 3 or 4 inches diameter. The whole of the stuff is now passed
through two revolving sieves of different mesh, and then hand-picked by
children and sorted into three qualities: (1) "prills," consisting of pieces of
very nearly pure ore; (2) dredge, or second quality, in which the ore is more
or less interspersed with the matrix; and (3) halvans, or waste. The prill
ore (1) is riddled through 3-inch square holes, and the two sizes are disposed
of as follows :—
(a.) Fines, o to inch size
(6.) Roughs, to 3 inch size, to crushing-mill and reduced to sizes o to inch. To pile for market.
The dredge ore (2) undergoes crushing, classifying, sizing, and jigging.
At Devon Consols, Captain Isaac Richards some thirty years ago employed
in connection with the crushing rolls a set of sizing trommels, mounted
successively end to end, and a classifying wheel, the former for sizing the
grains into groups suitable for jiggers, the latter for obtaining equivalents
for the buddles. The approximate disposal of the stuff from the crusher may
be thus formulated :—
(1.) Heads to pile.
(c.) Sand (volumetric grains) to jigger. (2.) Middles reduced in crusher.
(d.) Slimes (equivalents) to buddles
(3.) Tails to halvan heap.
(1.) Heads to pile.
(2.) Middles retreated.
(3.) Tails to halvan heap.
(1.) Heads to pile.
(2.) Middles for retreatment.
(3.) Tailings.
Heads to pile.
Tails to halvan heap.
786
[BOOK III.
PRACTICAL MINING.
Owing to the increase of transport facilities throughout the world, and
the consequent extension of the area of mining operation, copper-mining, as
an industry, has become very seriously curtailed in this country. In 1859
Cornwall and Devon alone produced 182,391 tons of ore, containing
11,831 tons of metallic copper. In 1881 the quantity raised in the two
counties was only 43,389 tons of ore, yielding 2,947 tons of metal. Thus the
quantity of copper obtained from the ore raised in 1881 was barely 25 per
cent. of the weight produced twenty-two years ago.
Tin ore, as already stated, exists in the primary rocks, diffused, or in
distinct veins. Tin ore is also found in deposits, filling up low situations
between hills, or in river beds, whence the name of stream tin has been
derived. These detrital deposits are almost exhausted.
Ordinary tin veins in their characteristics do not differ from copper or
lead veins. In some parts they contain very little of the ore sought for,
being filled with sterile veinstone, or they may in places be so narrow as
not to pay for working, or widen to such an extent as to enclose large deposits
of ore.
In some of the Cornish mines veins which were productive near the
surface have been found poor for hundreds of feet in depth, then again rich for
succeeding depths, a notable example being the present Dolcoath mine. This
formerly was a rich copper mine, but from 130 to 180 fathoms below the adit
the lodes were exceedingly poor, while at this time the lode at 420 fathoms
from the surface is 40 feet wide, and is unusually productive in oxide
of tin.
The merchantable ore of tin is a peroxide, which, when pure, contains
78.6 per cent. of metallic tin and 214 per cent. of oxygen. The impurities.
with which it is associated are mostly quartz, iron, arsenical and copper
pyrites, and wolfram. The specific gravity of these minerals is such as to
admit of their hydraulic separation into groups, but the separation of arsenical
pyrites, from oxide of tin and wolfram, can only be effected after the former
has been roasted and converted into oxide of iron, while wolfram can only
be removed from oxide of tin by a chemical operation. On the assumption
that tinstone contains the minerals referred to, and that these are liberated
and properly classified, the following will be the approximate order of their
separation:-
GANGUE.
Quartz
Chloride.
Slate
•
Copper pyrites
Iron pyrites
•
ORES
Mispickel (arsenical pyrites)
•
Peroxide of iron
Wolfram
•
Densities.
2.65 to 2.80
•
2.65,
2.85 (1) Separate approximately together.
•
2.50",
•
4.10",
" 5'03
•
4.83
" 4'30
6.00 6.40
""
} (2)
Ditto
ditto.
·
6.50", 7.10 (3)
Ditto
ditto.
•
7.15, 7:55
The black tin raised at present in Cornwall amounts to 1,000 tons
monthly, to produce which, fully 60,000 tons of tinstone have to be stamped
to a fine powder, and subsequently submitted to a complicated series of
manipulations. In its rough state the average value scarcely exceeds £1
per ton, while at present prices dressed ore or black tin may be taken at
£55 per ton.
An analysis of a parcel of black tin, dressed and ready for sale, gave,
according to Moissenet, the following results :-
CHAP. IV.]
Oxide of Tin
DRESSING OF TINSTONE.
Combined
Oxide of Iron {Free
Stony gangue
Water
92.00
1.66
3}
787
Oxide of Tin
93.66
4.32
2.00
99.98
2.66} Gangue
2'00
99.98
Metallic Tin
72.312
A microscopic examination of grains of veinstone, and minerals, from
the stamp-grates shows that they take the form of larger fragments of the
same substances; that is to say, the grains present similar irregular and
angular appearances. Several conditions exist in Cornwall which prevent
a quick, ready, and cheap concentration of the black tin associated with
mixed ores and gangue: (1) The tin stuff from the grates often clot into
small patches. (2) These patches do not break up at the proper place
in the dressing apparatus; consequently, the black tin which they retain
is not deposited in the position assigned to it. (3) The water used in
dressing, rendered viscid by the stamping process, retains the finer
grains of tin in suspension. (4) The viscid character of the water is not
only detrimental to a good classification of the grains, but, if slightly
charged with sand, it exercises an erroding effect on the rough or broken
surface of the stuff deposited on the enriching tables. (5) A portion of the
grains passed through the grates often contains highly minute grains of
black tin, less than o'oi mm. in diameter, which fail to settle at the head
or even at the middle of the first enriching tables.
It therefore follows that the loss of black tin in the tailings must always
be an appreciable one. The best authorities on this subject have, after
numerous experimental trials, arrived at the conclusion that the tailings
from the enrichment of tinstone may be regarded as containing from 2 lbs.
to 3 lbs. of black tin per ton. Taking the higher expression as more nearly
approaching the fact, it follows that the oxide of tin included in the waste,
and lost to the mines, exceeds 900 tons yearly.
The cost of stamping and dressing tinstone to afford 1 ton of black tin
differs to a slight extent in almost every mine, but if the dressing be
economically done the stamping will be about 1s. 9d. and concentration
Is. 6d., or together 3s. 3d. per ton. In some cases, however, the cost of
stamping and dressing will amount to 4s. per ton of stone. The normal
dimensions of tin grains differ in stuff taken from the same lode, while a
mine may have two or three lodes each affording a "different grained tin,”
and marked differences in the composition of the gangue.
Tin capels,
almost without exception, contain fine grain tin, and should be reduced so as
to pass through a fine grate, say 36 holes to the lineal inch, while coarse-
grained tin may be satisfactorily released from the matrix if stamped so as to
pass through grates 30 or 33 holes per lineal inch.
3
The machinery employed for the purpose of dressing tinstone includes
the stamps for reducing the stone into grains, varying in their dimensions
from o mm. to mm.; the centre-head buddle and concave buddle, for
getting rid of a portion of the waste; the tossing or packing tub, for further
separating waste from the oxide of tin present; the calciner, for roasting
or calcining the partially-dressed tin stuff or whits so as to get rid of
3 E
788
[BOOK III.
PRACTICAL MINING.
arsenic or sulphur with which it may be associated; the pulveriser, for
reducing the roughs to a gritless sand; and the slime frame, for concentrating
the black tin contained in such sands. Distinct opinions prevail upon
various questions connected with the enrichment of tinstone; one dresser
asserts that it should pass from the stamp-grates into drags or strips,
and undergo a partial concentration within this apparatus; another
that strips are unnecessary, and that the stuff should go direct to the
buddles, while other dressers take exception to one dressing-machine and
prefer another; thus the use of Williams's buddles will be advocated in one
district and objected to in another, while opinion would seem to be almost
divided as to the respective merits of the centre-head and concave buddle.
It were much to be wished that the dresser would properly classify the tin
stuff in front of the stamps, when, with suitable apparatus, the dressing
operation might not only be simplified, but the loss of black tin in the
tailings would be lessened, although it can never be absolutely prevented.
These observations will be found to acquire weight from remarks on tin-
dressing by Captain Charles Thomas, of Cook's Kitchen, contained in a
paper read at a meeting of members of the Mining Institute of Cornwall.
3
9
"From the Mineral Statistics for 1881 it appears that five Devonshire and
ninety Cornish mines raised together 12,898 tons of black tin, and that
957 tons were obtained from streams, rivers, and foreshores, being nearly
1th of the whole in weight, or in money value th. This quantity is actually
returned, but how much more runs into the Atlantic cannot be ascertained.
It is certain, however, that after passing over three or four miles of frames
set in the Red River the stream workers close to the sea earn a livelihood
from the 'waste' sent from our mines. In stamping tinstone the grateways
are often too small. At Cook's Kitchen the front grates are 28 inches long
by 9 inches high, the end grates 9 inches long by 9 inches high. The size
of hole depends on the nature of the stuff stamped. In process of stamping
the tinstone is divided into three classes - 'crop tin,' 'fine tin,' and
'dredge.' The 'dredge tin' is that small proportion found in the 'rows,'
the 'heads' of which are generally restamped or pulverised. This is the
least important portion of the tin, and can be easily secured.
The 'crop
tin,' too, on account of its high specific gravity, is also easily collected, but
the 'fine tin' is only partly obtainable after frequent and careful manipu-
lation. It is this fact which gives value to the 'tin streams,' the fine black
tin being carried into them in large quantities as slime tin.
"The great question to solve in tin-dressing is, how can the slimes be
'untinned'? The practical conclusion forced upon me is this: The round
buddle in front of the stamps receiving the 'slimes' and 'rows' is effectual
inasmuch as the 'rows' untin the 'slimes. In other words, the 'rows'
form a kind of filter through which, assisted by the buddle sweeps, the slime
tin is filtered. The dimensions of the buddle are-external diameter 21 feet,
with a 10 feet centre-head, which leaves an annular working floor 2 feet
wide. This floor is approximately divided into the head, I foot 6 inches
wide, crease, 2 feet wide, and tail, 2 feet wide. Such a buddle will dispose of
the stuff reduced by 12 or 16 stamp heads. In stamping stuff producing,
say, 40 lbs. of tin to 1 ton of stuff, the head may be buddled once, tossed once,
CHAP. IV.]
WHEAL AGAR TIN DRESSING.
789
and immediately calcined, while in stuff producing 75 to 100 lbs. of tin to the
ton, the head may be calcined at once. Thus it is possible to take out
80 to 85 per cent. of the produce in the first process without having recourse
to barrow, shovel, or manual labour other than the labour necessary for
removing the stuff to the calciner. Repeated trials have given similar
results. For example, from a parcel of tin stuff containing 13 cwts. of black
tin, produce 5 per cent., 10 cwts. of black tin were obtained from the head of
the buddle and carried direct to calciner. The great advantage of this
method arises from the fact that the 'slimes' are rendered quite 50 per cent.
poorer than by the ordinary process of tin-dressing."
The "slimes" run direct to the slime pit, after which they pass first over
a set of centre-head buddles, and then over frames.
•
The "rows" containing the "dredge tin" are deposited in strips, and
the heads restamped or pulverised; but it might be suggested that the
"rows" at this point be put through a jigger to separate the remaining
portion of the slimes. The "rows," or such portion of them as may be found
profitable, should then be pulverised. At Cook's Kitchen one of Michell
and Tregoning's pulverisers reduces about 6 tons in 24 hours.
With respect to the tin yard, and the treatment of the burnt leavings,
many dressers return these to the stamps; but by far the best method is to
pulverise them. Stuff of this nature, containing as it does about 15 per
cent. of black tin, and, being highly "corroded," requires very careful
treatment. The present mode of paying the dressing pare is defective. In
many mines from £1,000 to £2,000 worth of tin stuff is treated monthly, and
as only about 2 per cent. of this stuff consists of black tin the concentrating
process is necessarily tedious, and requires careful and intelligent superin-
tendence. The dresser superintending the stamp floors or frames has almost
the sole responsibility of treating the tin stuff, yet for his supervision he
usually obtains but £3 5s. or £3 10s. per month! Able miners at the same
time get £4 10s. to £5 per month. Now what is there for a man of even
average ability to aspire after in the tin-dressing department? Nothing
except the solitary chance of becoming a "captain dresser." Our over-
lookers, like enginemen in the Cornish mines, are underpaid, and the
consequence is that they watch the ringing of the bell with far greater
anxiety than the interests of adventurers. A man of moderate ability in
any department of labour, if he carries an extra responsibility, must be paid
for it. Overlookers must feel an interest in their work, and efficient men are
made mainly so by healthy competition with others, and where there is
nothing worth competing for good men will not compete.
The following description of tin-dressing as conducted at Wheal Agar,
Redruth, has been kindly furnished by Mr. Bedford McNeill, Associate of
the Royal School of Mines. The tinstone is reduced by means of the stamps
just sufficiently fine to liberate the black tin from the associated veinstone,
and the stuff having passed through a No. 36 copper grate, perforated with
holes barely one-half of a millimetre in diameter, is conveyed by means
of a launder into the middle of a centre-head buddle. The portions richest
in tin are deposited nearest the crown, while the stuff diminishes in
richness to the circumference, the slimes going away into settling-pits. As
3 E 2
790
[BOOK III.
PRACTICAL MINING.
soon as the buddles which may be designated No. 1 are full, the stream is
diverted into similar buddles No. 2. The "dresser" having examined the
"work" in No. 1 buddles, determines how much shall be considered (1)
"heads," (2) "middles," or "crease," (3) tails. The stuff is now shovelled
out, care being taken to keep each of the foregoing classes separate, and the
buddles, when empty, are ready for a second operation. As soon as a
sufficient quantity of "heads" from buddles No. I have accumulated they
are subjected to a second buddling operation, which is performed in concave
buddles. In this machine the "heads" are found at the circumference,
whilst the stuff decreases in richness to
decreases in richness to the centre, from which the
waste flows away to settling-pits. The "heads" from buddle No. 2 still
require to undergo a third or even fourth operation, for which concave
buddles are again used, by which time the "heads" produced are, as a rule,
sufficiently rich to be "tossed." Both this as well as the subsequent opera-
tion of “packing" is performed at some mines mechanically, but at Wheal
Agar it is done by hand. The "tossing" is carried out in large tubs or
kieves, which are first partly filled with water, and into which a charge of
the richest "heads" is gradually added, the whole being kept thoroughly
agitated until the kieve has received the full quantity; the agitation is now
discontinued, and the kieve is smartly tapped or packed on the outside by
means of an iron bar. The passage of the heavier or richer particles of stuff
to the bottom of the kieve is thus accelerated, whilst the poorer and lighter
portions collect towards the top. The whole is then allowed to stand, after
which the water is removed. The top portion or skimpings are put aside for
subsequent buddling, while the remaining contents of the kieve are con-
sidered fit for the burning-house. The numerous divisions of stuff of varying
richness thus obtained by the foregoing operations are buddled and
rebuddled with a view of gradually eliminating the sterile portions. From
the slime collected in the settling-pits the main bulk of water is first
drained off, when the slime is gradually washed into a launder by means
of a small jet of water, and is so carried to one or more concave buddles.
These give an enriched product for still further concentration, "tails" which
go to "frames" whilst the slimes are conveyed to settling-pits. It is the
ultimate product of these operations, or "slime tin," which so greatly taxes
the ingenuity of the tin-dresser to secure, the water stealing away as it were
to a considerable extent the finer portion of the slime tin present. In the
subsequent process of calcining, on account of the excessive fineness of the
slime tin, it is necessary to treat it distinct from the coarser product obtained
in the main buddling operation.
Calcination or burning has for its object the removal of the sulphur and
arsenic, occurring as mundic and arsenical mundic along with the oxide of
tin. The sulphur is converted into sulphurous anhydride and totally lost,
whilst the arsenic is volatilised and condensed as arsenious acid in a series of
long flues built for that purpose, and becomes "crude arsenic," a source of
revenue to the adventurers. Formerly the burning was accomplished in a
reverberatory furnace, having a large square hearth and low roof. Such
furnaces are now, however, almost exclusively reserved for the treatment of
slime tin, whilst mechanical calciners, as Brunton's or Oxland and Hock-
CHAP. IV.]
MACHINERY FOR ENRICHING ORES.
791
ing's, are employed where the production of black tin is such that they can
be kept continuously at work. In Brunton's calciner, at Wheal Agar, the
charge previously dried is fed from above on to the centre of a revolving
circular hearth, a series of "flukes" or iron stirrers gradually turning
the stuff over until it reaches a point near the circumference, where a
"scraper" removes it from the bed altogether into the "wrinkle," the speed
of the bed being so regulated that the stuff shall be roasted "dead" or
"sweet" before it reaches the "scraper." The burnt product in the wrinkle
whilst hot is usually cooled with water, and is then treated in a series of
centre-head buddles, the slimes from which go to a settling-pit, whilst the
tailings or burnt leavings reduced still finer by means of Michell and
Tregoning's pulverisers, Fig. 202, are re-buddled. The heads from the first
buddle are again treated, and so progressing to the tossing and packing
operations, are gradually brought into the marketable condition known as
black tin. All the various sizes of black tin obtained at various stages of
the dressing process are thoroughly mixed so as to send a uniform product
to the smelting-house. Oxland and Hocking's calciner may be briefly
described as a huge inclined cylinder revolving on its axis, with the fireplace
at the lower end, while the "whitts" are fed at the upper end, and gradually
part with their sulphur and arsenic during their passage through the length
of the cylinder.
The machinery requisite for the enrichment of distinct classes of ore
cannot well be grouped within the limits at our command. The quantity of
stuff to be disposed of within a given period, the value of the ore, the
character of the veinstone, the difference of density between one substance
and another, the price of labour, together with other direct or collateral
circumstances, must carefully be considered. But in most cases the machines.
enumerated in the following list may be successfully applied for the purposes
stated :-
1. Stone-breakers
2. Crushing Mill
3. Disintegrators
4. Stamps
•
REDUCING MACHINERY.
For reducing to fragments hard and non-elastic stuff, for the cobbing
process, crushing stamps, and disintegrators.
For reducing to grains stuff for jiggers and buddles.
For reducing stuff to sand for jiggers or buddles.
For reducing stuff for treatment in fine sand jiggers, buddles, or tables.
5. Edge-runners, Horizontal) For reducing dredge-grains to size suitable for treatment on buddles
Mills, and Pulverisers
1. Kilns .
2. Wash Trommels .
1. Trommels (volumetric grains)
2. Single and Divisional Classi-
fiers, Ascending Columns,
}
and tables.
WASHING Apparatus.
For disintegrating and freeing veinstone, in order to render it suitable
for hand-picking, cobbing, stone-breaker, and crusher; also partly
for the sizing trommels and jiggers.
Ditto.
SIZING AND CLASSIFYING APPARAtus.
For sizing stuff, sometimes for hand-picking, but chiefly for coarse and
fine sand jiggers.
Dividing Cones, and Py-For classifying stuff for fine sand jiggers, buddles, and tables.
ramidal Boxes (equivalent
grains)
1. Rotatory Separator
2. Figgers
CONCENTRATORS.
For freeing sand from slime, and partly classifying the sand for jiggers
or buddles.
For getting rid of worthless vein stuff and increasing the metallic per-
centage of the resulting product for subsequent treatment.
792
[BOOK III.
PRACTICAL MINING.
1. Rough Figgers..
2. Coarse Sand Figgers.
3. Fine Sand Jiggers
4. Slime Sand Figgers
SEPARATING AND ENRICHING MACHINERY.
5. Convex and Concave Buddles
6. Side and End Blow Tables.
7. Brunton's and Slime Tables.
8. Dead Frames
For dividing stuff into (1) castaways, (2) orey stuff, (3) ore, the stuff
ranging in size from 10 mm. to x.
For separating grains from 3 mm. to 10 mm., into (1) waste, (2) orey
stuff, (3) ore.
For separating sand from 4 mm. to 3 mm., into (1) waste, (2) orey stuff,
(3) ore.
For separating sand from o mm. to § mm., into (1) waste, (2) orey stuff,
(3) ore.
For separating sand from
stuff, (3) ore.
mm. to 2 mm., into (1) waste, (2) orey
For separating sand from o mm. tomm., into (1) waste, (2) orey
stuff, (3) ore.
For separating sand from o mm. tomm., into (1) waste, (2) orey
stuff, (3) ore.
For concentrating fine tin or lead slimes into (1) waste, (2) tin or orey
stuff, (3) black tin or ore.
GENERAL TABLE RELATING TO ORE-DRESSING MACHINES. '
Approximate
Quantity
worked per
10 Hours.
Approximate
Horse-power
required.
Gallons of
Water
required per
Minute.
Rotating Picking Table
""
""
Band
•
Common Skimming Jigger, coarse stuff
""
""
fine
""
Kember's Continuous Jigger
Continuous Coarse Sand Jigger
""
""
Fine
Sand Slime
Round Buddle
Concave Buddle
Side Blow Table
End
""
Dead Frames
""
""
•
•
•
Cwts.
200
150
2호
​2
20
15
8 to 10
5 ",
6
variable
""
100
100
|
Per sectional inch.
20
1
I
HALA
Ни
I //
| eperZtZperere>>
15
20
18
15
14
7
| | ~ |
:
CHAPTER V.
DISCOVERY AND EXTRACTION OF IRON ORES FROM VEINS AND
NATIVE IRON-
Meteoric Iron
MAGNETITE-
Magnetic Iron Ore
SPECULAR IRON-
Red Hæmatite
Red Iron Ore
GÖTHITE-
OTHER DEPOSITS.
IRON ORES OF THE UNITED KINGDOM.
Localities from which they are principally obtained.
GREG and LETTSOM* give a list of 20 British meteoric
stones, with date of fall.
CORNWALL-Redruth, St. Agnes, Roche, Penryn.
DEVONSHIRE-Haytor, Brent, Tavistock.
SCOTLAND-Portsoy, Shetlands, Isle of Islay, Isle of
Bute.
IRELAND-Antrim.
Cornwall-Pool, St. Just, Lostwithiel.
DEVONSHIRE-Hennock.
LANCASHIRE-Ulverston, Whitehaven.
SCOTLAND-Ayrshire.
CORNWALL-Lostwithiel, Redruth, St. Just, St. Austell.
Hydrous Oxide of Iron {DEVONSHIRE-Shaugh, Tavistock.
LIMNITE-
Brown Hamatite
Bog Iron Ore
Wood Iron Ore
SIDERITE-
Spathose Iron
Carbonate of Iron
ILMENITE AND ISERINE—
Titaniferous Iron Ore
Menaccanite
VIVIANITE-
Phosphate of Iron
PYRITES-
CORNWALL-Lostwithiel, St. Just, Perran, St. Austell.
DEVONSHIRE-Dartmoor, Brixham.
SomersetsHIRE-Brendon Hills, &c.
DURHAM-Weardale.
NORTH WALES.
IRELAND-Antrim, Leinster, Ulster, Wicklow.
SCOTLAND-Lead Hills, Shetland.
CORNWALL-St. Just, Perranzabula, St. Austell, Lost-
withiel.
DEVONSHIRE-Plympton, Tavistock, Christow, &c.
SOMERSETSHIRE-Brendon Hills, Exmoor, Toy Bridge.
DURHAM-Weardale.
SCOTLAND-Isle of Arran, Orkney, &c.
CORNWALL-Menaccan, St. Kevern.
CHESHIRE-Birkenhead.
SCOTLAND-Argyleshire, Shetland.
CORNWALL-St. Agnes, St. Just.
DEVONSHIRE-Tavistock.
LANCASHIRE-Furness.
CORNWALL-Abundant in mines.
DEVONSHIRE-Ditto.
Iron Pyrites
CUMBERLAND-Alston, Nenthead.
Sulpide of Iron
PYRRHOTINE-
SCOTLAND-Perthshire, &c. &c.
IRELAND-Antrim, Wicklow, &c.
CORNWALL-Botallack, Truro, &c.
Magnetic Iron Pyrites
Devonshire-Beeralston, Brent, Ilsington.
IRELAND-Donegal, Fermanagh.
MISPICKEL
Arsenical Iron
CORNWALL-Abundant.
DEVONSHIRE-Devon Great Consols, Tamar mines.
SCOTLAND-Aberdeenshire.
IRELAND-Waterford, Wicklow.
Iron Ores not from the Coal Measures.-Iron ores occur sometimes in
well-defined lodes, often in beds, and not unfrequently filling cavernous
spaces in the Limestone rocks, or the cavities in the upturned edges of
the older strata.
* "Manual of the Mineralogy of Great Britain and Ireland." By Robert Philips Greg, F.G.S., and
William G. Lettsom.
794
[BOOK III.
PRACTICAL MINING.
The following notices of the geological conditions under which iron is
found, the mineralogical characteristics by which the ores of iron are
distinguished, and the commercial value of the different varieties of the ores
of irons are mainly due to Mr. Richard Meade,* who has made the iron and
steel industries of the United Kingdom the subject of his especial studies.
The ores of iron which do not belong to the Coal Measures are widely
diffused through the rocks of Great Britain. The ironstone measures of our
coal fields furnished, at an early period, upwards of three-fourths of all the
ironstone smelted in our blast furnaces. The supply in recent years from the
same source does not exceed 40 per cent. of all the ferruginous ore raised in
the kingdom. With the growing demand for iron in the early years of the
development of our railway system, when the ironstone obtained from our
Coal Measures was insufficient to meet the requirements of our ironmasters,
a great impetus was given to the discovery of other sources of supply,
leading eventually to the development of the deposits of the North Riding
of Yorkshire, or the Cleveland district, in the Middle Lias or "Marl stone,"
in Lincolnshire, to those of the Lower Lias, and in Cumberland, Lancashire,
and other districts in the Carboniferous Limestone, supplemented by the rich
hæmatitic ores imported from Spain.
Geological Conditions under which Iron Ores occur.-At the base of the
Lower Silurian strata iron ores have been traced, though not worked to any
extent; these deposits are enclosed in the Skiddaw slates, a strata described
as consisting "of many alternations of mud, sand, and grit deposits, now
converted into Slate, Sandstone, and gritstone," in some localities meta-
morphosed. The locality in Cumberland in which these deposits occur is
principally in the neighbourhood of Skiddaw. Hæmatite deposits in well-
marked veins are also recognised in the same rocks traversing Hunstone
Crag and Low Wood from north-east to south-west; but hitherto these
deposits have not been wrought.
Again, in the Granite of Ennerdale and Esk, in the same county,
numerous lodes occur, which have been worked to some extent. Other
varieties have been traced in the Ash and Felstone rocks of the neighbour-
hood, where they are well defined, and have been traced for nearly three-
quarters of a mile to the Keswick side of the mountain from Ore Gap.
The Granite of this area is tolerably uniform in its appearance, for the most
part red, due to the colour of the felspar, modified, however, by the few dark
specks of hornblende, and occasionally by mica and transparent colourless
quartz. The Skiddaw Granite gives an analysis 75°223 per cent. of silica,
II per cent. of alumina; the Eskdale Granite 73.573 per cent. of silica and
13.75 per cent. of alumina; the Ennerdale variety giving 67.180 per cent. of
silica and 16.650 per cent. of alumina. Some attempts have been made to
work the few lodes which occur in the Ennerdale district, but they have
not proved profitable. These lodes have been referred to as the source from
which the Whitehaven deposits have been derived, but such an hypothesis
is untenable.
The other localities in the United Kingdom of Silurian age, in which iron
"Coal and Iron Industries of the United Kingdom of Great Britain." By Richard Meade.
Crosby Lockwood & Co.
CHAP. V.]
GEOLOGICAL OCCURRENCE OF IRON ORES.
795
ore is known to exist, are chiefly in the County Wicklow, in lodes in the
Ballymurtagh and Cronebane mines enclosed in Clay-Slate, in the counties
of Longford and Cavan in the Lower Silurian rocks. Facilities for their
development are, however, wanting in the way of canal and railway com-
munication to the coast. The districts referred to in Longford lie between
Granard and Carrick-on-Shannon, and in Cavan between Ballyhoy and
Cavan.
Devonian Formation.-The deposits of ore found in the Devonian rocks.
are of the varieties known as spathic, brown, red, and magnetic ores; in
Somersetshire the spathic deposits are found enclosed in the upper division
of the Middle Devonian, known as Clay-Slate. These rocks near the
surface are of a greyish colour, acquiring in depth a green or bluish tint.
The Brendon Hills, in which spathose ores occur, range nearly east and
west at about 6 miles south, between Watchet and Minehead, and terminate
in a deep valley near Eisen Hill, in which similar deposits are found.
Exmoor several lodes of this ore are known.
On
In Devonshire, magnetic ores occur in well-defined lodes at Haytor, near
Ilsington; in the Clay-Slate of that district, the direction of the strata in
which they are imbedded being nearly north-west and south-east, under-
lying at the north-east at an angle of 22° or 23° for the first few feet from the
surface; below this, however, the dip is very regular at an angle of 45°. At
Smallacombe, also near Ilsington, in the decomposed Clay-Slate of the
district, brown hæmatite occurs in nodules forming irregular beds in a thick
mass of variegated clays, the innumerable layers of which slope gently a few
degrees only from the horizontal to the south-east.
In another locality, at Hennock, near Bovey Tracy, north of Ilsington, a
micaceous variety of ore is found bearing east and west in a close-grained
porphyritic Granite. This lode has been worked open to day for more than
a mile. At Buckfastleigh, in the South Devon mine, imbedded in Killas and
Limestone, brown hæmatite occurs. Again at Torbay, on the south coast,
near Brixham, a similar variety is found in the Devonian Limestone, which
is tilted at a considerable angle, and presents a broken appearance near the
surface, the fissures containing the ore having, it is said, a direction east
and west. In North Devon and West Somerset, extending from Ilfracombe
to Bridgewater, iron lodes have been discovered, occurring both in regular
strata and veins, often tilted with the shales in which they occur, and at
such considerable angles as to render their working difficult.
In Cornwall one of the most important deposits is that of Restormel, held
under lease from the Duchy of Cornwall. The sett containing this deposit
extends north and south for 12 mile, and is enclosed in Clay-Slate or
"Killas," dipping to the east. Brown hæmatite is also known to occur in
several localities in a line coincident with the magnetic meridian, coursing
from a point a few miles east of St. Austell on the south, to the estuary of the
Camel at Padstow on the north, namely at Ruby, Kinghtor, Treverbyn,
Coldvreath and Retiire, Withiel and Pawton. The lode at the last-named
mine, situated 5 miles from Padstow and 3 from Wadebridge, occupies a
distinct fissure in the Clay-Slate, the Killas of this district being brownish
red, rather soft, and readily decomposing when exposed to the air.
Cold-
796
[BOOK III.
PRACTICAL MINING.
vreath and Retiire produced in 1881 1,400 tons of iron ore, and 330 tons were
shipped from Padstow, obtained from Lanivet and other mines in this locality.
The most extensive iron ore deposit in Cornwall is at Perranzabula. The
Perran lode, as seen on the north coast of Cornwall, consists of two great
branches divided by a horse of Clay-Slate. Considerable explorations have
been made at Great Retallack and at the Duchy and Peru mines, now worked
for zinc as the Duchy mine. Many other localities in Cornwall are known to
yield iron ore; of these the district of Constantine, west of Falmouth,-
the Ruthers mine, near St. Columb, and the Indian-Queens and Trelivian
mines, near St. Austell, may be referred to as the more important.
Carboniferous Limestone.-The chief varieties of iron ore developed in
this series of rocks are nodular carbonate, brown and red hæmatites,
and spathic ores. In Northumberland, at Ridsdale, in the Carboniferous
Limestone series, as well as in a few other localities, at Brinkburn and
Rothbury, nodular ironstone (carbonate) has been obtained; the quantities,
however, were never considerable. The brown hæmatite of Dean Forest, in
Gloucestershire, was first worked about the year 1650, and as the rich
character of the ore became better known the deposits were more fully
developed. The mineral basin of Dean Forest has a superficial area of about
34 square miles, and is more perfect in form and outline than any other
coal field in Great Britain. The iron-ore deposits are enclosed in the
stratified masses of the Limestone in extensive hollows, or chambers,
caverns, or churns, which occur in the dip of the enclosing strata, near the
outcrop or basset on the eastern side of the Forest, decreasing gradually
towards the centre of the basin.
Cumberland and Lancashire.-Iron ore of carboniferous age is well
developed in the Mountain Limestone around Whitehaven, where it consists,
in its lowest part, of about 250 feet of massive Limestone, reposing upon
that division of the Lower Silurian system known as Skiddaw slates. The
principal masses of ore are found in large irregular deposits, occasionally in
the form of shallow fissures, also in flat deposits following more or less
closely the dip of the beds, which have an inclination of from 12° to 18°
to the west, or filling caverns in the Limestone. The area of these deposits
in the Whitehaven district from south-west to north-east extend a distance
of about 8 miles, with an average width of 1 mile, while in the neighbourhood
of Millom the ore-bearing Limestone occupies an area of 1 square mile.
In Lancashire, as in Cumberland, the hæmatite deposits are found under
nearly similar conditions; there are, however, some points of difference in
the deposits of the two areas very clearly set out by Mr. J. D. Kendall,
F.G.S.,* who, in his valuable paper, divides Furness into two districts,
the one including the high ground northward from Ulverston as far as the
head of Windermere and for several miles on both sides of Coniston Lake,
a part of the Lake country; the other the low-lying ground, a continuation
of the long narrow belt in West Cumberland which lies between the sea
and the western hills of the Lake country. The mode of occurrence of
hæmatite in the Furness districts is not confined to irregular deposits in the
"Hæmatite Deposits of Furness." ("North of England Institution of Mining and Mechanical
Engineers," vol. xxxi. 1882.)
CHAP. V.]
IRON ORES OF THE LIAS AND OOLITE.
797
Limestone, it also occurs in fissures more or less regular, having a north-
west and south-east strike, with a dip to the south-west.
Alston Moor and the Weardale Districts of Northumberland and Durham.—
Here the spathic and brown hæmatite ores obtained from the Carboniferous
Limestone are found occurring in veins traversing the Limestone. In the
lead-mining districts of Allenheads and Weardale, spathose ores occur in
regular lodes, and in the flats which insinuate themselves laterally into the
Limestone. These deposits at Weardale have been extensively quarried.
Lower Lias.-In North Lincolnshire, in the districts of Frodingham,
Appleby, and Brigg, important deposits of iron ore have been developed in
recent years, giving rise to great and growing mining industries in a
district previously agricultural. In the north-western area of the county, the
rocks dip in a direction from west to east, and comprise Liassic and Oolitic
strata. The important ironstone deposit of the area of the district around
the village of Scunthorpe is described as commencing below with a hard
band of Limestone, intercalated with softer bands of a dark brown texture,
intermingled with a brown earthy deposit. The Lower Lias clay in this area
has a maximum thickness of 90 feet. The bed containing the ironstone in
this district attains, in some places, a thickness of 27 feet, and is found but a
little below the surface. There are other localities where ironstone has been
worked in some quantity, as at Kirton Lindsey, north-east of Gainsborough;
at Caythorpe, north of Grantham; at Claxby and Caistor; and at Monk's
Abbey and Greetwell, near the city of Lincoln.*
Middle Lias or Marlstone.-Brown Oolitic, and ores of argillaceous car-
bonate of iron, exist abundantly in this division of the Lias. The Liassic
rock covers a large area, extending from Wiltshire in the south to the North
Riding of Yorkshire or Cleveland district, the area of greatest development
being in the last-named district. The Cleveland Hills, containing the great
repositories of argillaceous iron, extend from Ormesby on the north, near
Middlesborough, to the coast, and in a southerly direction to the valleys of
Eskdale and Rosedale. It is observed of this important deposit that its
greatest development appears in the northern area of the field, diminishing
both in the thickness of the beds and the quality of the ore in its extension
to the south and east of the area.
The other localities in which these ores of argillaceous carbonate have
been wrought are situated chiefly in Oxfordshire, at Adderbury, Aynho,
Fawler, and in the neighbourhood of Banbury, near Woodstock. At
Fawler the ore deposits lie upon soft sands, composing the lower division of
the Marlstone, being surmounted by the clay of the Upper Lias.
Lower Oolitic (brown oolitic and magnetic ores). The iron ore occurring
in this stratum is found in the subdivision known as the "Northampton
sands," ironsand and Sandstone, the equivalent of the Stonesfield slate,
reposing on the Upper Lias clay. In the north of the county and on the
borders of Leicestershire the bed of iron ore is well defined extending for
miles along the Midland Railway to Finedon, and thence to Welling-
borough, Blisworth, and on to the town of Northampton. One interesting
*For a detailed account of the ironstone deposits of North Lincolnshire, the Rev. T. H. Cross's
paper, in the "Journal of the Geological Society of London," vol. xxxi., 1875, p. 115, should be consulted.
798
[BOOK III.
PRACTICAL MINING.
feature in the working of these deposits is that the covering or soil, being
but a few feet in depth, is easily removed, exposing the iron ore. When
the iron ore is removed the soil is restored, and the land is then available for
agricultural purposes, its appearance not even suggesting that the ground
had been disturbed.
Magnetic iron ore has long been obtained from the lower beds of the
Lower Oolite, in a seam known as the "Dogger Bed," well developed in the
Rosedale Abbey mines; it is also known as the "top seam," and is
regarded as the equivalent of the Northampton sand.
Middle Oolite.-—In a division of the Middle Oolite, deposits of iron ore
are found, the coral rag in which the ore occurs being described as consist-
ing of beds of fossiliferous Limestone containing corals and shells in a frag-
mentary condition. The chief locality is at Westbury, in Wiltshire, where
it has been worked for many years.
Lower Cretaceous (brown and calcareous ores).—This formation, including
the Wealden, has two great divisions, the Weald Clay and the Hastings
Sand, upon which reposes the Lower Greensand. It is in this subdivision
and high up that the iron ore occurs in reticulating veins, crossing in all
directions the sandy strata in which they lie. The Lower Greensand strata
in the Isle of Wight are considerable, giving in section, when well developed,
upwards of 900 feet. The iron ore hitherto worked in the Lower Greensand
has been found in deposits occurring at Seend, in Wiltshire, at Linslade, in
Buckinghamshire, and at Tealby, in Lincolnshire. None of the above-
named deposits, however, have been worked recently.
Miocene. The most recently developed deposits of iron ore in the United
Kingdom are those of the County Antrim, in the north-east of Ireland,
occurring in rocks of Miocene age in the Tertiary system. The basalt,
through which the iron ore is interstratified, is generally referred to as being
divided into three classes: the amorphous, the columnar, and the concre-
tionary, the varieties of ores wrought being known as brown, aluminous,
pisolitic, bole, and lithomarge. An interesting paper, describing the iron
ores of the County Antrim, has been written by Mr. J. D. Kendall.* The
chief localities producing these ores are situated at Ballymena, Glenravel,
Portrush, Glarryford, and Glenariff; Bauxite being obtained at the Irish
Hill and Straid mines, near Ballymena.
Beyond this general statement of the geological condition under which
the iron ores of the United Kingdom are found, it appears necessary to
direct attention to a few of the phenomena which attend the varied deposits
upon which explorations have been carried out.
The iron ore occurring in the Skiddaw slates appears in well-marked
veins which have been occasionally worked. The chief of these have a general
north and south trend upon the hills between Buttermere and Ennerdale
Lake; eastwards from Helvellyn there is a large vein running east of
Kepplecore Tarn, across the lower end of Red-tarn Beck, to the foot of Nab
Crag, and probably through a gap in the Glenridding Screes; and other lodes
in Patterdale, crossing from north-west to south-east, occur, but these veins
have not yet been opened out.
*Colliery Guardian, 27th October, 1876, p. 657.

CHAP. V.]
SPATHOSE ORES OF BRENDON HILLS.
799
The lodes traversing the Granite of Eskdale and Ennerdale have a general
north and south direction, often but a few inches in thickness, but occasionally
reaching from 10 to 12 feet. In Ireland, as already stated, hæmatite of
Silurian age is worked in the County Wicklow, at the Ballymurtagh and
Cronebane mines; in the former mine, the lode to a depth of 16 fathoms is
found rich in ore, after which it passes into the ordinary pyrites of the neigh-
bourhood. This lode was first wrought about the year 1856. In Cronebane
mine the ore is found on the backs of the mineral veins near the surface,
to depths varying from 8 to 25 fathoms, occurring as a "gossan" resting
upon Clay-Slate and pyrites, which becomes firmer and harder in depth.
The spathic ores of iron, rich in manganese and valuable for the produc-
tion of Spiegeleisen, are not found extensively in Great Britain. The greatest
depository of these ores occur in Somersetshire, in the upper division of the
middle Devonian, rocks in the Brendon and Eisen Hills, and on Exmoor;
other deposits are found in Durham and Northumberland, in the Carboniferous
Limestone of Alston Moor and Weardale, and a few localities in other
formations in Cornwall and Devon, especially below the lead lodes in Perran-
zabula, and of the Exmouth and Frank Mills mines, in Christow.
The deposits of the Brendon Hills possessing a considerable range, which
have been worked from an early period,
have been worked by the Ebbw Vale Iron
Company. The earliest workings-the
Colton pits at the eastern end of the
Brendon Hills-were in a zigzag form;
to the west, considerable workings-
thought to be Roman-were carried on
at Raleigh Cross and at Burrow mine,
near Wiveliscombe; while farther west,
at Florry mine, the old workings were
found to have a depth of 30 feet.
feet. The
lode of spathose ore which occurs in
this mine is of very striking character.
Fig. 228 gives an accurate representa-
tion of a section at Raleigh Cross.
α
b
a
a
Fig. 228.-Brendon Hills.
show the enclosing walls, which are
Devonian slate, and the central portion
is a fragment of the same rock completely
surrounded with the spathose ore b. This
must evidently have been a fragment
splintered of which the iron ore was being deposited. Farther to the west,
explorations show the course of the deposits, which have been traced to
Exmoor, where several lodes have been from time to time worked.
To the Perran iron lode, occurring in the Devonian rocks, Mr. W. J.
Henwood* called attention nearly half a century since, referring to it
as a large vein bearing south-east and north-west, and dipping south
50°. The lode is seen on the northern coast of Cornwall at Perran, where
it attains a width of 100 feet, and it extends to Mount and Trebisken. He
* "Transactions of the Geological Society of Cornwall," vol. v.
800
[BOOK III.
PRACTICAL MINING.
says: "At the eastern extremity of Ligger Bay is a large vein bearing
south-east and north-west, dipping south 50°. It contains hæmatite, specular
and earthy brown iron ore, quartz, and slate." As this lode is first seen in
the Perran cliffs it is divided by a "horse" of Killas: it has been traced to
Deer Park mine, which is at a distance of four miles. At this mine it
appears to suffer some disturbance. It takes a direction at first directly east,
and afterwards some degrees north of east. The lode is said to have been
traced as far as Grampound, but this is problematic; certainly no iron ore of
any value has been raised beyond the Deer Park mine. The Perran lode
has been worked for about twenty years, and it is said that 200,000 tons of
ore have been taken out and sold.*
At the cliff, which is nearly 200 feet high, considerable quantities of
brown hæmatite have been raised. An old adit-the date of which is not
known-was extended in 1871-72, and widened so as to allow of tram
waggons working on an inclined plane. A shaft was sunk inland for
ventilating the workings, which are, at this point, extensive. The lead lodes
from a neighbouring mine, known as Wheal Golden, cross the iron lode,
and fine stones of lead ore have been broken out of it.
Another shaft, Borlase's, has been sunk 15 fathoms, and a level driven to
meet a large excavation on the south branch of the lode, known as the "Big
Iron Pit." This portion of the sett, now known as the Gravel Hill mine, was
formerly called the Penhall iron mine.
To the eastward of Gravel Hill, the Halwyn sett, which is bounded by the
Mount mine, comes in. The iron ore is here raised from a depth of rather
more than 20 fathoms. Treamble is still farther east, where brown hæmatite
and spathose iron ores have been extensively worked. Each of the Treamble
quarries are crossed by a promising lode of argentiferous galena, and some
lead ore has been raised from these lodes within the Great Retallack sett.
At Great Retallack mine the lode is several fathoms wide. It has been found
to contain much iron ore to a depth of 40 fathoms. Zinc ore was found in the
lode for the first 25 fathoms, and at a greater depth the blende increased, and
for some time 500 tons per month were sold.
To the east of Great Retallack, is the Duchy mine, where workings on
the lead and copper lodes were carried to a depth of 50 fathoms, and on the
iron lode to between 20 and 30 fathoms. The Peru lode is only a few inches
wide, but it gave silver lead of great richness, some parcels containing as
much as 2,000 ounces of silver per ton of ore. Some of this silver was in
visible fibres of metallic silver. The author possesses a small mass of lead ore
from the neighbouring Mount mine, which is hollow, and completely filled with
fine threads of metallic silver. Mr. W. J. Henwood † says: "At Trebisken
Green a lode, oblique in direction to the large iron vein so well known in the
same neighbourhood, affords irregular masses of rich ore. This for the most
part is galena, which sometimes contained no more than o‘000153, but in some
cases it has yielded as much as o'091922 to 0.104040, and even o*122584 its
weight of silver. Portions of the lode have, however, produced 0.107100 their
* "The Great Perran Iron Lode." By J. H. Collins, F.G.S. ("Report of the Miners' Association
of Cornwall and Devon for 1873.")
"Account Books of the Mine," quoted by Mr. W. Jory Henwood. ("Transactions of the Royal
Geological Society of Cornwall," vol. viii. p. 121.)
CHAP. V.]
SILVER IN TREAMBLE IRON LODE.
801
weight of metal from vitreous silver ore and native silver unmixed with lead.
The ore sold from Trebisken Green mine has been-
Price per Ton.
£ S.
a.
95 10 6
74 3 4
Amount.
£
s. d.
164 15 6
7 3 4
4I 4 4
100 14 I
1
Quantity.
T. c. qr. lb.
1859. Sept. 14
Sept. 26
I 14 2 O
O 200
1860. Mar. 13
O I 3 16
435 10
O
0 14 3 19
135 0
O
0 4 3 II
7 10
ΙΟ O
""
Aug. 14
I 9
O 12
2 19 O I
333 7 6
97 o o
485 3
286 3 10
7 6 1 3
1 16 4 (Slimes)
O
£1087 5 11 total value.
Captain Nicholas Bryant states that from the Trebellen lode parcels of
ore were sold for £700 per ton (Collins).
Mr. J. Carne stated that about 1788 the first discovery of silver ore was
made "in a mine in the parish of Perranzabula, which was in consequence
dignified with the name of Mexico." Mr. W. W. Smyth says: "This silver-
bearing vein crosses through the iron lode in the Treamble workings, and
does not appear to have been made out or followed up on the south of them.
. . At the present time (1881) two north and south veins coming in from
the north are to be seen in the Duchy mine, having a very pronounced dip
to the eastward, distinctly cutting through the iron lode, promising in
appearance, but disappointing so far in their productiveness."
Cellular brown hæmatite is raised in considerable quantity from the
western boundary of the Duchy sett. Much of the ore contains kernels of
white carbonate of iron, and water which is quite clear and tasteless.
At 20 fathoms from the surface, east of the shaft known as Vallance's
shaft, is a very hot end. In this end the air is very bad, it being quite
impossible to keep a candle burning in it. A thermometer has indicated the
temperature of this end as 124° Fah. This high temperature is due to the
oxidation of a large mass of iron pyrites.
It is a remarkable fact that the great masses of iron ore in the Perran lode
occur just where it is crossed by the lead lodes of the district. The Wheal
Golden lodes cross at the cliff, where the lode is 100 feet wide, the Trebisken
and Trebellen lodes in Mount mine, the Great Retallack lodes in Treamble,
the Duchy Peru and Wheal Hope lodes, the Shepherds' lode, and others.
The effect of these junctions is also seen in the lead lodes, which all contain
large proportions of silver near their junctions. All indications appear to
point to the probability that, in depth, the iron lode will pass into copper,
galena, or blende.
I
A few other localities in which lodes of iron occur in Cornwall remain to
be referred to. At Boscarne, west of Bodmin, a lode, partly wrought, has a
run of 750 fathoms, with an average width of 1 fathom. At Nantallon, south
of Boscarne, three lodes occur, two having a run of 1,750 fathoms, and the
third 2,200 fathoms; the width of one of the lodes being 3 feet and the remain-
ing two 6 feet each. Again, to the south and west of Bodmin, at Tremoor,
two lodes, extending 2,000 yards and averaging 3 feet wide, occur. Other
lodes at Coldvreath, with a north and south direction extending some
800 fathoms, have been proved having a width of about 1 fathom.
I
802
[BOOK III.
PRACTICAL MINING.
In Cumberland and Lancashire the chambers or caverns in the Limestone
are of considerable extent, the thickness of the deposits varying from 30 to
100 feet in depth and even more; the forms of the deposit are very irregular,
and it has been observed that their general direction corresponds with the
magnetic meridian. The deposits at Parkside exhibit a section in greatest
depth of 70 feet, the area extending over about 60 acres. At Millom the
deposits have an area of nearly 1,000 acres. Mr. J. D. Kendal* divides the
deposits in the Carboniferous Limestone into four kinds : 1st, bed-like
deposits; 2nd, vein-like; 3rd, dish-like; and 4th, irregular-shaped deposits.
In Furness they may be separated into three kinds: 1st, vein-like; 2nd,
dish-like; and 3rd, irregular-shaped; and remarking that, as far as he is
aware, there is not a single "bed-like" deposit in the Furness district, unless
the small flats from the Lindal Moor and Stank veins be considered as such.
In the Furness district some of the most important deposits occur. That at
Lindal Moor has been worked about 1,000 yards in length in a direction
north 25° west, and south 25° east, its breadth being very variable, ranging
from a few inches to 30 yards. Again, at the Stank mines the ore occurs in
a similar mass, the direction of it tending to about 25° north-west and south-
east. This has been worked for a length of about 600 yards and for a depth
of about 30 yards without reaching the bottom. The width varies from a
few inches to 25 yards, including the masses of Limestone which are imbedded
in the ore. Most of the ore deposits are of the dish-like form. In their
simplest outline they are roughly-like filled irregular basins just below the
drift. While at times it is observed that deposits of this kind are so long as
compared with their breadth that they seem almost like veins, these "dish-
like" deposits, so common in Furness, are rarely met with in the Whitehaven
district.
Of the irregular-shaped deposits, the most important in Furness is
at Askam, its total area being about 16 acres; its length in a north and
south direction would be about 260 yards, and from east to west about
300 yards. It is overlaid by about 16 fathoms of drift, and on the dip
side of the deposit where it has a rock roof the ore extends to a depth of
40 fathoms. It is remarked of this deposit, notwithstanding its irregular
form, that it has the same dip as the Limestone, extending to a less depth on
the rise side where it comes up to the drift than on the dip side where it has
a rock roof. This appears to be a common feature of the deposits both in
Furness and Whitehaven.
The "kidney" and "puddler's" ores, extensively mined in the neighbour-
hood of Whitehaven, in Cumberland, and Ulverston, in Lancashire, are by
far the most important ores raised in the United Kingdom, the kidney ore,
which occurs in the harder varieties of hæmatitę, deriving its name from the
circumstance of its appearance presenting a finely-lobed surface.
general character of the Whitehaven hæmatite at Cleator Moor is as
follows: "compact red hæmatite, easily scratched by a file; lustre, earthy;
colour, purplish grey; streak, bright red; fracture, uneven; containing
The
* Mr. J. D. Kendal, "On the Hæmatite Deposits of Furness," read before the "North of England
Institution of Mining and Mechanical Engineers," vol. xxxi.
1882.
+ "Iron Ores of Great Britain," Part I. p. 61, published in "Memoirs of the Geological Survey of the
United Kingdom."

1
CHAP. V.]
DEPOSITS AT HODBARROW MINE.
803
cavities lined with crystals of specular iron, and containing in some cases
quartz." The amount of metallic iron in two samples of Cleator Moor ore
being 63 25 per cent. and 66.60 per cent. The total output of the White-
haven mines in 1881 amounted to 1,615,635 tons, of the value of £1,186,709.
The hæmatite of Lancashire in the Furness district is divided by Mr.
J. D. Kendal, in his paper on these deposits,* into three classes, the first class
being hard compact blue purple ore, in which there are numerous loughs, lined
with kidney-like concretions and spar, such as occur in the Whitehaven
deposits. This variety is found in the northern end of the Lindal Moor
deposit, in the Stank deposit, and in part of the Askam deposit. Analyses
of these ores give of metallic iron 55'03 per cent., 58.10 per cent., and 65.98
per cent. respectively. The second class consist of a dull reddish purple ore,
found at the southern end of the Lindal Moor deposit, in part of the Stank
B
A
SECTION LINE
MOS
C
A
TL
ST
ATER
HOD BARROW
POINT
No. 2.
D
C
B
DRIFT
RED ORE
CT
Fig. 229.-Hodbarrow Iron Mine.
LIMESTONE
deposit, and elsewhere, the softest being known as puddling ore, and giving
of metallic iron from 54.06 per cent. to 60'55 per cent. The third class is
distinguished as soft dark ore, and is the most abundant ore in the district of
Furness, being that which is mainly found in dish-like deposits, the analyses
of four samples of the soft ores giving respectively of metallic iron 42:43 per
cent., 48.81 per cent., 52'75 per cent., and 59'13 per cent. It may be observed
that 45 per cent. represents the average of metallic iron in the poorer ores
of Furness, similar ores in the Whitehaven district giving 50 per cent. The
total output of the Lancashire hæmatite deposit in the year 1881 amounted
to 1,180,836 tons, of the value of £755,827.
A few additional words are necessary on the remarkable deposit at Hod-
barrow, near Holborn Hill, which is shown in plan and sections in Fig. 229.
* "Proceedings of the North of England Institution of Mining and Mechanical Engineers," vol. xxxi.
1882.
3 F
804
[BOOK III.
PRACTICAL MINING.
The two sections, A B and C D, given, one crossing the other at right angles,
show that the depth of these deposits is not great. The deposit has flowed
in from the east, and regularly filled the subterranean pond previously pre-
pared to receive it. This immense deposit extends from above the line of
high water in the Duddon to beyond the line of the coast under the bed of
the river. The production of iron ore from this mine for the last ten years
has been as follows:
Year.
Tons.
Value.
Year.
Tons.
Value.
1873
203,791
£254,738 13
1878
274,962
£185,599 7 6
1874
201,663
252,078 15
1879
293,637
161,500 0
1875
202,817
254,162 10 O
1880
348,194
240,236 0
1876
271,098
189,768 12 O
1881
358,621
251,034 0
1877
277,195
202,645 0 0
1882
453,823
340,142 0 0
The workings of such immense masses of iron ore are necessarily attended
with difficulties. In the hardest ore they are not unfrequently 40 feet wide,
and sometimes they extend to 70 feet; as a rule, however, about 16 feet is
the width fixed by experience as the most suitable. The height is generally
from 10 to 12 feet, but often it extends to 20 or 30 feet.
In the Parkside mines, Whitehaven, a working 70 feet in height also
claims a short notice. Timber is not generally employed, the Limestone
rock and the iron ore being generally sufficiently coherent to support
itself. When the height of the iron ore is considerable and the deposit
irregular, the rise is completely laid open by drifts, driven up the sur-
rounding Limestone, or "pinnell," as it is locally called. Sometimes, on
account of the soft and incoherent nature of the ore, much advance cannot
be made without the use of considerable quantities of timber. When all the
ore is obtained that can be got out with safety, great caution is required in
removing the pillars which have been left to support the roof. On the
removal of these the ore above and around, unable to support the incumbent
mass, subsides, and an end is brought to that portion of the mine. The
crushing of a mass of ore with the Limestone and drift above it will be best
understood by Fig. 230, which is an exact representation of such a crush in
one of the Whitehaven mines :—
Water
Old Shaft
Water
New Shaft
Timber
Middling of Ore
Middling of Ore
Limestone
Fig. 230.-Crush in Iron Mine.
These remarkable deposits of iron ore have been, without doubt, derived
CHAP. V.]
THE EGREMONT IRON MINE.
805
from the older rocks-in all probability from the Old Red Sandstone,
which has been entirely removed from the district north of the Whitehaven
and the Furness iron districts. The Old Red Sandstone, always rich in
iron, would, in the process of denudation, furnish all that was required. The
process by which this was effected demands more careful consideration
than it has hitherto received. When the Sandstone, impregnated with
the peroxide of iron, was being removed by denudation, the waters by
which this was effected were highly charged with carbonic acid derived
from the vast masses of vegetable matter which were undergoing decom-
position. This vegetable matter in decomposing reduced the peroxide of
iron to a state of protoxide, which would be dissolved as a supercarbonate
of the protoxide of iron in the highly carbonised water. By a previous
action this carbonised water, in flowing through the Limestone, dissolved
out large quantities of the rock, and thus formed the caverns and cavities.
into which the peroxide of iron was eventually to be deposited. In the Coal
Measures adjoining the Parkside mine, Whitehaven, a thin stratum of argil-
laceous iron ore was discovered spreading over a coal bed to some extent.
So long as an abundance of vegetable matter was present the peroxida-
tion was prevented, and the iron mingled with clay went down as a protoxide
or formed a bed of clay-band ironstone. Escaping from the mass of
decaying vegetable matter in which this carbonate of protoxide was formed,
the atmosphere was constantly producing films of peroxide on the surface,
and iron in its highest degree of oxidation. Red hæmatite was precipitated
in the caverns, and water-worn fissures prepared to receive it.
The accompanying woodcut (Fig. 231) represents an illustrative section
W
Nº1 Shaft
Shaft
E
لا
~W
الله
الله
الله الحمد
!!!
DRIFT
RED ORE
LOWER
SILURIAN
Fig. 231.-Egremont Mine.
CARBONFS
LIMESTONE
of the Egremont mine, Whitehaven. It will be seen that a channel has been
in the first instance formed in the Carboniferous Limestone, which has sub-
sequently been completely filled in with red hæmatite iron ore, in the manner
described.
The beds of ironstone in the Lower Lias formation in North Lincolnshire
3 F 2
806
[BOOK III.
PRACTICAL MINING.
extend over a large area with a varying thickness. The ore is obtained by
open quarry workings as in Northamptonshire, the "over-burden," or soil
covering the ironstone, being inconsiderable in depth, is easily and inexpen-
sively removed, not requiring skilled labour.
The area of greatest development of ironstone in the Middle Lias is dis-
closed in the Cleveland Hills, in the North Riding of Yorkshire, at the top
of the Middle Lias, or "Marlston Rock." At Eston the bed of ironstone
attains its greatest thickness, varying from 12 to 17 feet. This seam is also
known as the "Pecten Bed," from the fact of the occurrence throughout its
area of the well-known fossil shell (Pecten æquivalvis).
At Upleatham the main seam previously referred to has a thickness of
13 feet, exhibiting a varied character, in which the one general structure is
maintained. At Gisborough, at the Challoner mines, the main seam has a
thickness of from 12 to 13 feet; at the Normanby mines it does not exceed
11 feet; while at the Loftus mines, near Loftus, it does not exceed 9 feet
6 inches. Towards the south of the district the seam is found thinning out
until Felix Kirk is reached, a district a few miles north-east of Thirsk,
where the same bed is found to exist in a section of 6 or 7 inches, with shaly
partings of 3 feet.
The beds of ironstone in the Middle Lias in Oxfordshire vary from 2 to 10
and even 12 feet in thickness, and of a very compact character, often present-
ing the appearance of a solid rock. The stone has been worked for many
years at Adderbury, and some has been raised at Fawler and a few other
localities in the county. The ore in this area was first worked about the
year 1859, and at the present time the deposits at Adderbury are the only
deposits worked in Oxfordshire.
The iron ore deposits in the Lower Oolite of the Northamptonshire area
have a varying thickness, from about 4 or 5 feet to upwards of 20 feet, with
an equally varying "over-burden." In the neighbourhood of Duston and
Gayton, to the west of Northampton, the ironstone varies from 10 to 12 and
16 feet thick with a covering of soil, &c., of about 5 feet. In Wellingborough
the ironstone varies from 12 to 16 feet in thickness; between Kettering and
Thrapston some good sections are met with at Islip, Woodford, Cranford,
and Kettering, where the ironstone exceeds 20 feet, and in one or two places
it was formerly mined by underground workings. The ironstone now in
course of development is all open quarry workings, and an acre of ironstone
in the Wellingborough district is estimated to yield upwards of 10,000 tons
of ironstone.
The beds of iron ore occurring in a subdivision of the Middle Oolite,
known as the "coral rag," are limited to a few localities and of inconsider-
able extent, that at Westbury being the most important, where it has a thick-
ness of 15 feet, and it has been traced from the Westbury Iron Works, where
the ore is smelted, up through Steeple Ashton into Oxfordshire, by Rowde,
near Devizes, and the high ground south of Chippenham.
The ferruginous ores obtained from the Lower Cretaceous strata are of
comparatively low percentage, and are therefore not worked. The deposits
at Seend in Wiltshire occur in the Lower Greensand, where they have an area
exceeding 150 acres, the over-burden in places not exceeding 1 or 2 feet. These
CHAP. V.]
HAEMATITIC IRON ORES.
807
deposits have been for some years undisturbed. In Buckinghamshire, at
Leighton Buzzard and Linslade, ironstone in the Lower Greensand is found,
not in a continuous bed, but in nodules large, massive, and of a brown
ochreous character, often hollow, and containing loose white sand. Another
deposit of similar age occurs at Tealby, in Lincolnshire, where the bed has a
thickness of 6 feet, made up of Oolitic grains; this ore is regarded as a
useful ironstone in admixture with other ores.
The brown and aluminous rich ores of the County Antrim consists of
several beds, the uppermost or Pisolitic bed having a thickness varying
from a few inches to 2 and 3 feet, and consisting of a soft brown or reddish-
brown ferruginous ochre, in which are imbedded small dark grey irregular
pieces of harder ore. Beneath the Pisolitic bed is a seam composed of a
yellowish-red ferruginous ochre, containing a number of concretionary
nodules of basalt called "Bole," with a varying thickness of from 5 to 10 feet.
The lowest bed, known as "Lithomarge," and consisting of a variegated soft
rock of a prevailing blue slaty colour, contains, like the bole, concretionary
nodules of basalt; this bed at times attains a thickness of nearly 80 feet.
The Character of the Various Ores of Iron.-The iron ores obtained from the
rocks of Great Britain may be regarded as of two varieties, oxides and car-
bonates; the former including magnetite, or magnetic iron ore, hæmatite, of
which there are several varieties known to the iron smelter, and limnite,
or brown iron ore.
Of the magnetic iron orcs, the chief deposits wrought in Great Britain
occur in Rosedale, in the North Riding of Yorkshire. The year of greatest
production was 1873, when 560,668 tons of ore were raised, of the value of
£168,200. Since that date a great falling off appears, the output in the year
1880 amounting to 6,079 tons, since which date operations have been sus-
pended. The amount of metallic iron in these ores, according to analysis by
Messrs. Crowder and Pattinson, of Newcastle-upon-Tyne, gives from 45°43 per
cent. to 49 20 per cent. The Rosedale ore was chiefly smelted at the works
of the Rosedale and Ferryhill Iron Works, and to some extent at other
works.
Hæmatite.—The varieties may be generally summarised as specular iron
ore, micaceous iron ore, kidney ore, and puddler's ore, the last named
being much used for lining the hearths of puddling furnaces. The first
named is not found abundantly in the rocks of Great Britain. The micaccous
deposits of iron ore worked are inconsiderable; the deposit at Hennock, in
South Devon, where the ore occurs in a close-grained porphyritic Granite,
being associated with quartz, schorl-clay, and hornblende, has not been
recently worked.
Brown Iron Ores, or Limnitc.-There are several varieties of this ore,
described generally as being of a brown colour, sometimes yellowish-brown,
with a rather dull sub-metallic or silky lustre, often with a shiny black
coating. The Dean Forest ores of Gloucestershire are of three varieties:
one, a compact, close-grained, black ore, locally known as "Brush ore,”
giving 63.50 per cent. of metallic iron; the second, a cellular or spongy
variety, often tough, also black and very rich; and the third, a broken
earthy-looking ore, less rich in metallic iron, but used extensively in admix-
808
[BOOK III.
PRACTICAL MINING.
ture with the other varieties by the iron smelter. Other analyses of the
Forest ores give 63.04 per cent. of metallic iron, and a more earthy variety,
known as "Smith ore," 62.86 per cent.; "Grey ore," 34°46 per cent.; and
"Brandy Brush," 22'93 per cent.
In Cornwall, the brown hæmatite of Restormel consists principally of a
crystallised variety known as Göthite, occurring in fibrous and mammillated
aggregations, and also in long prismatic crystals. These ores, examined by
Mr. J. Pattinson, of Newcastle-on-Tyne, are found to contain metallic iron
varying from 31.90 to 55 per cent.; the average, however, may be taken as
45 per cent.: the presence of manganese in considerable proportion render-
ing them of much value for the manufacture of iron and steel. In the ad-
joining county of Devonshire the ore raised at Smallacombe, near Ilsington,
contains 50.44 per cent. of metallic iron, the ores of Torbay, near Brixham,
yielding from 44'56 per cent. to 63 per cent., and even more.
The brown hæmatite wrought in the Silurian rocks at the Ballymurtagh
mine, in the County Wicklow, gives of metallic iron from 46 to 50 per cent. The
year of greatest production was 1864, when 25,164 tons were brought to bank,
of the value of £7,744; the output in 1881 being but 1,433 tons, of the value
of £430.
Another deposit of brown hæmatite to be noticed is that worked at West-
bury, Wiltshire, in the Coral Rag; of this ore two kinds are recognised,
brown and green. The general character of the ore is of a dark ochreous
kind, presenting a greenish appearance when freshly broken, the brown ore
giving 41.99 per cent. and the green ore 38 per cent. of metallic iron. This
deposit was first worked about the year 1858, when 5,719 tons were raised; the
year of greatest production being 1871, when the output amounted to 109,151
tons; while in 1881 the production was but 39,222 tons, of the value of £7,844.
In Northamptonshire and Lincolnshire, the brown ores of iron, fur-
nishing nearly 15 per cent. of the ore reduced in the blast furnaces of the
kingdom, produced in 1881 in the first-named county 1,270,544 tons, of the
value of £176,426; Lincolnshire producing in the same year 1,021,506 tons,
of the value of £154,600. Numerous analyses of the Northamptonshire ores
give the average yield of metallic iron of these ores as about 40 per cent.
This is exceeded in some localities; for example, Brixworth ore gives 43 per
cent., Towcester ore 46.67 per cent., and Cogenhoe ore 48 per cent. of
metallic iron.
The brown Oolitic ores of Lincolnshire which were examined by Mr.
Charles Tookey, of the Royal School of Mines, from the bed at Brigg, near
Frodingham, gave an average of 40'67 per cent. of metallic iron; other
samples from the various bands of the main bed, yielding, according to
other results, from 28.80 per cent. to 33 per cent., and as much as 44°25
per cent., some parts of the deposits being highly manganiferous.
The ores of Oxfordshire, of brown Oolitic variety, are inconsiderable,
amounting in 1881 to 8,614 tons, of the value of £1,507. The ore raised at
Adderbury—a calcareous variety—gives from 36 to 37 per cent. of metallic
iron.
The iron ores-which are rich in manganese, rendering them of great
importance in the manufacture of pig-iron, especially when it is to be con-
CHAP. V.]
ALUMINOUS ORES OF ANTRIM.
809
verted into steel-have been analysed by Mr. John Spiller, of the Royal
School of Mines, giving 34'65 per cent. of metallic iron and 9.78 per cent. of
manganese. The spathose ore of Weardale, examined by Mr. A. Dick—
described as "easily scratched by a file; lustre, semi-vitreous; colour,
yellowish grey; streak, white; fracture, crystalline "-yielded on analysis,
38.56 per cent. of metallic iron, the protoxide of manganese amounting to
2'42 per cent. The spathose ore raised at Frank Mills and South Exmouth
mines, examined by the late Dr. Noad, contains 38.26 per cent. of metallic
iron in the raw ore, increased to 54°70 per cent. in the calcined state.
Argillaceous Carbonates of Iron.—These ores, raised extensively in the
Cleveland Hills of the North Riding of Yorkshire, are well described in
the "Memoirs of the Geological Survey."* The memoir relating to iron
ores being out of print, it will be convenient to give a description of the
ore raised at Eston, in Cleveland, in the mines of Sir Joseph Pease and
partners. It is said to be: "Chiefly a carbonate of the protoxide of iron;
lustre, earthy; colour, greenish grey; streak, similar; fracture, uneven,
showing now and then small cavities, some of which are filled with carbonate
of lime. Throughout the ore are diffused irregularly a multitude of small
oolitic concretions, together with small pieces of an earthy substance resem-
bling the ore, but lighter in colour." The amount of metallic iron contained
in this ore amounts to 33.62 per cent. The average amount of iron contained
in the ores of Cleveland may be taken at about 30 per cent., the calcined
ore yielding 40°81 per cent. of metallic iron. The Cleveland ores vary in
their contents of metallic iron from 28.60 to 35°47 per cent. at the South
Bank Works, the ore raised at Upleatham yielding 31'97 per cent.
An early
return in 1854 gives 650,000 tons, increased to 1,471,319 tons in 1860, and
4,072,888 tons in 1870, the year of greatest production being 1881, when the
output of 27 mines in operation amounted to 6,538,471 tons, of the value
of £1,062,501, the average value of the ore at the mines being estimated at
from 3s. to 3s. 6d. per ton.
The brown aluminous ores of Antrim alone remain to be referred to. Those
of Glenarm and Carnlough giving, the first named, 35'96 per cent. of metallic
iron and 30 per cent. of alumina, as determined by Mr. C. A. Heywood, of
Whitehaven; the Carnlough ores, examined by Mr. Tosh, yielding 22:47 and
17.89 per cent., the respective proportion of alumina varying from 33.69 to
34°55 per cent. Another aluminous ore raised at the Glenariff mines,
examined by Mr. Jones, of Wolverhampton, a second-class ore, gives 25°15
per cent. of iron and 36.50 per cent. of alumina; the best aluminous ore
obtained from the same mine yielding 47'40 per cent. of metallic iron and
10.19 per cent. of alumina.
The Bauxite deposits of the Irish Hill and Straid mines, near Ballymena,
examined by Mr. John Pattinson, gave of alumina 53.83 per cent., 52′00 per
cent., and 46.13 per cent.
The production of these aluminous ores in Ireland in the year 1857
amounted to 3,000 tons, increased in 1867 to 42,016 tons, of the value of
£10,641; and in 1877 to 155,382 tons, of the value of £85,427; and in 1881 to
198,429 tons, of the value of £85,495.
* "Iron Ores of Great Britain," part i. p. 95.
3
810
[BOOK III.
PRACTICAL MINING.
In concluding this notice of the iron ores of the United Kingdom-not
in the Coal Measures-we give the total production of the several varieties
in the years 1881 and 1882:-
Counties, &c.
Variety of Ore.
1881.
Quantities.
1882.
Quantities.
Tons.
'Tons.
Cornwall
Devonshire
Somersetshire
Gloucestershire
Red and brown hæmatite.
Magnetic brown and red
Spathose and brown hæmatite
Brown hæmatite
7,460
5,749
•
11,198
II,481
•
29,883
36,067
90,497
80,672
Wiltshire
Brown oolitic
•
•
39,222
99,176
Oxfordshire and Rutland
Brown oolitic
•
8,614
12,753
Northamptonshire
Leicestershire
Lincolnshire
Staffordshire, North
Brown oolitic
1,270,545
1,333,085
Brown oolitic
99,599
267,802
Brown oolitic
•
Calcareous hæmatite.
1,021,507
1,190,564
30,721
Lancashire
•
Cumberland
Yorkshire (Cleveland)
North Wales
Red hæmatite .
1,189,836
1,408,693
Red hæmatite.
1,615,635
1,725,478
Brown oolitic
than
6,538,471
6,326,314
Red hæmatite
Isle of Man
Ireland
Scotland
•
Northumberland and Durham
South Wales and Monmouthshire Brown hæmatite
Brown hæmatite
Aluminous
Brown hæmatite
Total production in the years 1881 and 1882.
The total value of the ore in 1881 amounting to £3,634,391. In the same
year the imports of foreign ores of iron were 2,450,698 tons, of the value of
£2,349,411.
It appears necessary, to render the description of the iron ores of the
United Kingdom complete, to add the returns, as given by the Inspector of
Coal Mines, of the argillaceous iron ores obtained from the Coal Measures
for the last five years :
Spathose and silicious hæmatite
70,771
83,726
•
2,155
81,372
120
2,471
77,162
199,863
5,235
189,724
1,907
12,312,711
12,852,824
1878
1879
1880
•
•
10,306,560 tons
11,871,745,"
11,664,726
1881
1882.
""
11,858,766 tons
I1,505,447,
The actual quantity of ore used in our blast furnaces in 1882 being
26,808,969 tons.
BRITISH MINING.
BOOK IV.
THE FUTURE PROSPECTS OF BRITISH MINING.
CONTENTS, OF BOOK IV.
CHAP. I. SUMMARY.-EXAMINATION
""
MINERALS.
OF THE PROBABLE EXHAUSTION
OF METALLIFEROUS
II. ON THE LIMITS OF THE METALLIFEROUS ZONE IN THE ROCKS OF BRITAIN.
III. THE OCCURRENCE OF ORES AT GREAT DEPTHS;—OR IN NEW DISTRICTS.
IV. IMPROVEMENTS AND ECONOMY IN WORKING BRITISH MINES.
V. EXAMINATION OF THE WHOLE SUBJECT AND CONCLUSIONS DRAWN THEREFROM.
BRITISH MINING.
BOOK IV.
THE FUTURE PROSPECTS OF BRITISH MINING.
CHAPTER I.
SUMMARY.—EXAMINATION OF THE PROBABLE EXHAUSTION OF METAL-
LIFEROUS MINERALS.
Tin.-Until 1845, in which year the author was appointed "Keeper of
Mining Records," no successful effort had been attempted to obtain reliable
returns of the quantities of metalliferous ores obtained annually from the
mines of the United Kingdom.
Several estimates,—many of them made with a considerable amount of
care,—had been from time to time published, giving the production, within a
given period, of the mines of certain defined districts, or producing some
special mineral. These were derived from very varied sources of information,
many of them of uncertain value, and it was not possible, therefore, to make
an estimate of the real condition of any set of mines, upon which reliance
could be placed.
The chief purposes for which the Mining Record Office was established,
will be seen from the following Minute of Resolutions, passed by the Council
of the British Association at the meeting in Newcastle-upon-Tyne, August
25th, 1838. It appears important, as a matter of history, to give permanence
to this; showing, as it does, that a very few years effects a change in the
opinions of men, on questions which were at one time considered to be
settled as of vital importance, and alters arrangements which, when made,
contemplated the permanent preservation of records of the progress of the
most important industry of the United Kingdom :-
Ist. "That it is the opinion of this meeting that, with a view to prevent the loss of life and of property
which will inevitably ensue from the want of accurate Mining Records, it is a matter of national importance
that a depository should be established for the collection and preservation of such Mining Records of
subterranean operations in collieries and other mining districts.
2nd. "That a committee be appointed to draw up a Memorial, and to communicate with the Govern-
ment in the name of the British Association respecting the most effectual method of carrying the above
resolution into effect.
3rd. "That the committee consist of the following gentlemen, with power to add to their number:-
The Right Hon. the Marquis of Northampton.
Sir Charles Lemon, Bart., M.P.
Sir Philip G. Egerton, Bart.
John Vivian, Esq.
814
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Davies G. Gilbert, Esq.
J. S. Enys, Esq.
W. L. Dillwyn, Esq.
Charles Lyell, Esq.
The President for the time being of the Geological Society of London.
The Professors of Geology in the Universities of Oxford, Cambridge, London, and Durham.
H. T. de la Beche, Esq.
John Taylor, Esq.
John Buddle, Esq.
Thomas Sopwith, Esq."
In pursuance of the above resolutions a meeting was held at the offices òf Mr. Sopwith, in the Roya
Arcade, Newcastle, on Monday, August 27th. Present-
Sir CHALES LEMON, Bart., in the chair. The Rev. Dr. Buckland, the Rev. Professor Sedgwick,
Professor Phillips, Professor Johnson, John Buddle, Thomas Sopwith, and Richard Griffiths, Esquires.
It was proposed by Dr. Buckland and seconded by Mr. Sopwith-
"That Richard Griffith, of Dublin; Robert Bald, of Edinburgh; and J. Barker, of Bakewell,
Esquires, be added to this Committee."
It was proposed by Dr. Buckland and seconded by Mr. Buddle-“The Secretaries be appointed as
follows:-
John Taylor, Esq., F.R.S., F.G.S., General Secretary.
Thomas Sopwith, Esq., F.G.S., Secretary of North of England.
Richard Griffith, Esq., C.E., F.G.S., Secretary for Ireland.
Robert Bald, C.E., F.R.G.S., Secretary for Scotland."
Dr. Buckland having read the resolutions passed by the Council of the British Association, the
following Memorial was drawn up, and having been approved, Sir Charles Lemon undertook to transmit
it to the Chancellor of the Exchequer, which has accordingly been done, and the subject is now under
consideration.
Copy of the Memorial of the MINING RECORDS Committee.
"To the Right Honourable the Lords of Her Majesty's Treasury, &c.
"The Memorial of the COMMITTEE for the PRESERVATION of MINING RECORDS appointed
by the BRITISH ASSOCIATION for the PROMOTION of SCIENCE, assembled at Newcastle,
August 25th, 1838—
Humbly sheweth :
"That whereas it has been made apparent to your Memorialists that great loss of life and destruction
of property have resulted from the imperfect preservation of Mining Records; and whereas still greater
losses will inevitably ensue unless advantage be taken of the experience of living individuals, who are
willing to place in any public depository that may be provided, copies of the numerous mining documents
now in their possession;
“And whereas the preservation and economical use of mineral produce, and especially of coal, are of
great importance, not only to the proprietors of mines, but to the nation at large:
"Your Memorialists feel it to be their duty, respectfully and earnestly, to call your Lordships' attention
to the expediency of establishing, as soon as possible, a National Depository for the preservation of
documents recording the Mining Operations of the United Kingdom.
"That the experience of the neighbourhood of Newcastle, within the personal knowledge of several
of your Memorialists, affords appalling examples of the loss of life, and waste of highly valuable Mineral
Property, which would never have occurred had such documents been preserved as it is now the object of
your Memorialists to collect. As in the lapse of time mining operations become of necessity more
complicated and dangerous, the risk of the recurrence of similar catastrophes will be continually increasing.
It appears to your Memorialists that the only sure and effectual means of preventing those deplorable
results is the establishment of such a public office as has already been alluded to.
"The practicability of carrying out the above measures has been shown by what has recently been done
under the direction of the Board of Woods and Forests, in the case of the coal mines in the Forest of
Dean, and by the documents relating to the coal mines of Newcastle, which have been deposited by
Mr. Buddle in the archives of the Natural History of Newcastle. It is within the knowledge of your
Memorialists that an immense number of similar documents are in the possession of individuals who are
now willing to place copies of them in any public depository under the control of Government.
"Your Memorialists therefore humbly pray that your Lordships will be pleased to take the premises
into your consideration.
CHARLES LEMON,
Chairman."
(Signed)
The result of this was that the Lords of the Treasury adopted the recom-
mendations, and on the 29th September, 1840, the Mining Record Office was
established under the department of Woods, then presided over by Lord
Duncannon. It was placed in charge of Mr. (afterwards Sir Henry)
de la Beche, the Director-General of the Geological Survey, and of the
Museum of Economic Geology: Mr. Thomas Jordan being appointed the
first Keeper of Mining Records, which appointment he held until April,
1845. The author succeeded Mr. Thomas Jordan, entering on the duties of
his office on the 19th April, 1845.
CHAP. I.]
THE EARLIEST MENTION OF TIN
815
Interpreting the words of the above Memorial to signify not only the
preservation of plans, &c., of mine workings, but the returns of produce
from our metal mines and collieries, the author was induced to make the
experiment of soliciting from the proprietors accurate returns thereof. In
1847 the first attempts to collect Mineral Statistics were so far organised,
that a series of tables giving the produce of our copper and lead mines.
for several years* were issued, and in 1853 "Statistics of the Produce of
Copper, Tin, Lead, and Silver from the Mines of the United Kingdom from
1848 to 1852 inclusive "t was published.
In that year the Treasury appointed a committee to inquire into the
working of the several departments then under the direction of Mr. Henry
de la Beche. That committee reported most favourably on the work done
in the Mining Record Office, and recommended that it should be placed "on
a more efficient footing." The Treasury acted on that recommendation. The
Keeper of Mining Records was placed in a position to extend his inquiries,
and, since that date, "The Mineral Statistics of the United Kingdom" has
been regularly published each year until 1882, when the Mining Record
Office was abolished, and the business of collecting the "Mineral Statistics"
transferred to the Inspectors of Collieries and Metal Mines-the compilation
and publication being placed in charge of the Home Office.
This statement has been made for the especial purpose of showing the
extreme degree of uncertainty which prevailed in respect of the annual value
of the mineral productions, drawn from the rocks of the British Islands, pre-
viously to the organization of the system referred to. The question of the
importance of preserving records of all our subterranean works is admitted,
the Mines Regulation Acts requiring that the plans and sections of all
abandoned collieries and mines shall be sent to the Secretary of State for
the Home Department. This excellent provision is, however, rendered
seriously ineffective, by the clause regulating that those records shall be seen
only "by an inspector under the Act," until ten years have elapsed from the
period at which the plans were deposited.
Our present purpose is to examine, by such lights as are available—and
they are very few-the extent to which the traffic in tin raised in Britain
was carried on with the inhabitants of the countries on the eastern shores of
the Mediterranean Sea, and thus to endeavour to make an estimate-which
must be approximate only-of the total quantity of tin raised in Cornwall
and that portion of Devonshire which lies west of Exeter, from the com-
mencement of mining. In the Historical Sketch it has been shown,
that tin was known to Moses 1600 B.C., and, that Ezekiel mentions that
metal as being, 600 years B.C., an article of trade with the merchants of
Tarshish, and, earlier still, that Homer tells us it was used in the manu-
facture of a corslet. Herodotus, 440 B.C., mentions the metal tin, but he
says he knows not the islands from which it was obtained. Several other
instances might be adduced to prove that tin was not unfamiliar to the
ancient workers in metal. From whence did they obtain it? Undoubtedly
tin may have been procured from the Indian Archipelago, and from the
* "Memoirs of the Geological Survey,” vol. ii. part ii.
+ "Records of the School of Mines."
816
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
southern promontory of India, or it may have been gathered from the rivers,
or the mines, of Spain and Britain.
Assyria, it has been said, procured tin, for the manufacture of her bronzes,
from India by an overland route; and, seeing that the Phoenicians were
originally from that part of Asia, there is no improbability in supposing that
when they founded Tyre and Sidon, they kept up some traffic with their
ancient home.
This very obscure question has been examined with considerable acumen
by Dr. George Smith.* He quotes the Periplus of Arrian,†—a merchant
navigator of Alexandria in Egypt,-who had traded from the head of the Red
Sea to the coast of Africa, around Arabia and India, and to the Island of
Ceylon. Amongst his lists of imports into Egypt he names white copper,-
probably a bronze,—and brass and tin, in small quantity at a few ports only.
An examination of all that has been written on this subject, in the earlier
pages of this volume, leads to the conclusion that at least 1,200 B.C. the
Phoenicians, sailing round the coasts of Spain, discovered that the metal tin
might be obtained from that country. There is, also, strong evidence that
they made Gadez (the modern Cadiz) a port of importance, from which
they shipped this valuable product for the use of the metallurgists of Tyre.
Having established a trade between Gadez, and the countries on the
eastern borders of the Mediterranean Sea, these adventurous navigators
began to explore the coasts of the countries to the north, and thus they dis-
covered the “Tin Islands," of which Herodotus tells us, "It is nevertheless
certain that both our tin and amber are brought from those extreme regions."
The voyage of Himilco gives us, with tolerable clearness, a statement which
has the appearance of truth, that the voyage from Gadez to the Tin Islands
occupied at least four months. There exists evidence of a striking character,
which proves that the Phoenicians (vulgarly called Jews) established them-
selves, in small colonies, in several parts of the western promontory. The
remains of earthworks, and cyclopean walls, assure us, that the native miners
endeavoured to protect their tin ground from the strangers (Sarsens), and there
can be no doubt that the islands, spoken of by Diodorus, were the marts to
which the Celtic miners of Dumnonium took their tin for sale to the Oriental
merchants.
Five hundred years before the birth of Christ, there is but little doubt, that
there existed a trade in the metal tin, but to what extent this was carried on
we have no authority to guide us. When we reflect on the quantity of tin
which would be employed in Egypt, in Phoenicia, and in Greece, in the
manufacture of bronze; which alloy was employed in the construction of
weapons of war and implements of industry, in casting idols for worship and
ornaments for decoration, it appears that not less than 100 tens of this metal
could have been exported every year from Britain alone.
*The Cassiterides: an Inquiry into the commercial Operations of the Phoenicians in Western
Europe, with particular reference to the British Tin Trade." By George Smith, LL.D.
+ Under the title of "The Periplus of the Erythrean Sea." This work, which Dean Vincent translated,
he attributed to A.D. 64. The learned Dean of Westminster says, in his "Commerce and Navigation of
the Ancients in the Indian Ocean": "This work contains the best account of the commerce carried on from
the Red Sea and Coast of Africa to the East Indies, during the time that Egypt was a province of the
Roman Empire." Mr. W. D. Cooley, in his "Maritime and Inland Discovery," places considerable
reliance on this work of Arrian, as showing that tin was first brought to Egypt from India, forgetting that
Arrian wrote 1,600 years after tin was supposed to have been introduced.
CHAP. I.]
EARLY PRODUCTION OF TIN.
817
Julius Cæsar landed in Britain fifty-five years before the birth of Christ,
and the Romans held possession of these islands for three centuries and a
half.* The native inhabitants of Cornwall appear to have held almost
undisturbed possession of that district for all that period. The Roman
remains which have been found, and which are described, were few. These
probably show that some of the Romans, searching for gold, rather than for
tin, established themselves in some of the mining districts of the West. It
is, however, probable, as Cæsar tells us, "that the merchants who inhabited
the coasts of Gaul" resorted to Britain for trade. These merchants, we may
suppose, encouraged the search for tin, and established the overland route
through Gaul to Marseilles. This consideration would lead us to suppose
that during the period of Roman occupation as much tin was exported as
previous to the commencement of the Christian era.
The Saxons gained possession of Cornwall and Devon in A.D. 947, and
we are told of a ship laden with tin, sailing from Cornwall to Alexandria,
being under the protection of an angel. The introduction of bells greatly
increased the use of tin, and in the sixth century bells were commonly used
in France and in this country. All the old bells contain a notable quantity
of tin. Much of this metal was also then used for tinning iron and copper
vessels. In the beginning of the thirteenth century, Venice received tin from
Cornwall by way of Bruges, in Flanders, and Pisa and Genoa engaged
their own vessels in this trade.
Balducci† informs us that 1,000 lbs. of tin in Cornwall was then worth
10 marks sterling, the value of the mark being equal to 4 florins. We may
therefore infer, that after the departure of the Romans from Britain, to about
the landing of William the Conqueror—another 500 years—there must have
been a considerable increase in the produce of tin.
King John, in 1201, gave a charter to the Tinners, which was confirmed
and improved by Edward I. in 1305, and in 1337 Edward III. created the
Duke of Cornwall and organised more satisfactorily the Stannary Court,
which originated in the days of Athelstan, about 950 A.D. From the time.
of King John-who is said to have expelled the Jews, who had been for some
time the most industrious miners-the produce of tin fell off, and until the
reign of Henry VII. everything connected with mining was in a sad state
of confusion. In 1509, for the purpose of encouraging the production of tin,
the use of imported tin was forbidden. The importation could never have
been large, as this metal came only from Bohemia, Saxony, and possibly
from Spain. We are enabled to estimate, by the aid of some tables given
by Pryce in his "Mineralogia," the production of tin in Cornwall for a few
years, and from this fragmentary statement it is estimated that about 450
tons were produced on the average in each year. The same authority
informs us that in the seventeenth century the average of the metallic tin
produced was 1,500 tons per annum. This was, however, only after Eliza-
beth had introduced a considerable number of German miners. In the reign
of Queen Anne (1700 to 1714) there was an accumulation of tin (five years'
consumption is spoken of as being equal to 5,000 tons), and great deadness
* Professor J. Rhys, "Celtic Britain."
+ Francisco Balducci Pegolotti, "La Pratica della Mercatura."
818
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
of trade continued until 1789. The East India Company then becoming
speculators, we find the production of tin considerably improved.
G. R. Porter, Esq., F.R.S.,* gives a table from 1750,-when 2,876 tons of
tin were raised,-to 1834, when 4,180 tons were produced. The mean average
will be 3,000 tons a year, consequently in eighty-four years there will have
been produced 252,000 tons of tin. Until within the last twenty years the
fluctuations have been very immaterial.
Mr. Porter divides the periods as follows, the average produce of each five
years being-
Years.
Tons.
1750 to 1754
2,585
Years.
1780 to 1784
Tons.
Years.
Tons.
2,667
1810 to 1814
2,339
1755,, 1759
2,728
1785,, 1789
3,249
1815,, 1819
3,444
""
1760 1764
2,610
1790,, 1794
3,405
""
1820 1824
3,578
1765,, 1769
2,845
1795, 1799
3,084
1825,, 1829
4,595
1770,, 1774
2,853
1800 ,, 1804
2,676
1830,, 1834
4,047+
1775,, 1779
2,647
1805,, 1809
2,572
In 1820 one-fifth of the tin was "refined tin," but from that date the
quantity has been gradually increasing. This is used for preparing Dyer's
liquor (chloride of tin), and for tinning iron (making tin-plates). These were
formerly tinned with "grain tin" (tin smelted from the ore found in the tin
streams), but the quality of refined metal is so much improved, that by
most manufacturers no other tin is now employed. Some few, however, still
use common tin for the outer coat of the plate. The annual production of
tin for thirteen years from 1848 was as follows:
Year.
Ore.
Tons.
Metallic Tin.
Tons.
Ore.
Metallic Tin
Year.
Tons.
Tons.
1848 Produce of Tin Ore 10,176
6,784
1855 Produce of Tin Ore 8,947
6,000
1849
10,719
7,148
1856
"
9,350
6,177
1850
""
10,383 6,922
1857
""
9,783
6,582
1851
9,455
6,304
1858
10,618
6,920
1852
9,674
6,510
1859
10,670
7,100
1853
8,866
5,763
1860
10,462
6,695
1854
8,747
5,947
In the ten years ending 1849 we imported,-principally from the East
Indies,-10,166 tons 15 cwts. During the same period we exported Foreign
tin, 7,025 tons; and of British tin 16,078 tons. In the ten years from 1850
to 1859 we produced of—
British Tin
Imported Tin, and Regulus
65,098 tons.
25,324 ""
90,422 ""
We exported in the same time-Foreign Tin
British Tin
""
4,163 tons
16,735
""
20,898
Leaving for home consumption—69,524
The consumption of tin in Great Britain in each of the undermentioned
ten years shows a rapid increase :-
From 1791 to 1800
1801 1810
""
1811,, 1820
1821
,, 1830
1831,, 1840
Tons.
Tons.
7,545 or annually
754
II, 179
1,118
""
16,000
1,600
""
26,158
2,616
32,542
3,365
The cause of this advance in our consumption of tin has been the
*The Progress of the Nation in its various Social and Economical Relations from the Beginning of
the Nineteenth Century." By G. R. Porter. London: 1847.
† Eight hundred tons a year of tin were sent to China for many years.
CHAP. I.]
IMPORTS AND EXPORTS OF TIN
819
extension of our tin-plate export. This will be shown by the following
statement:
Tin Plates.
Boxes.
From Liverpool in 1850 we exported 460,184
""
1855
1859
•
""
""
591,276
811,051.
Canada Plates.
Boxes.
I1,420
I1,431
24,862
In addition to this, the employment of white metals, such as Prince's-
metal, Britannia-metal, German-silver, Albata plate, &c., as the basis upon
which electro deposits of silver are made, and the greatly increased use of
bronzes, have produced a larger consumption of this metal.
The difference between the imports and our exports of tin will be shown
by the following statement :—
Cwts.
Tons.
In 1820 we imported from Banca 1,309 and the exports were 3,047
,, 1825
""
""
4,231
,, 1830
""
""
15,539
""
1835
""
""
19,704
""
1840
,, 1845
""
""
""
""
9,391
12,085
""
""
4,709
10,426
""
23,795
""
6,594
""
19,153
As it regards tin ore (black tin), the following table represents the posi-
tion of our productive tin mines for ten years, as shown by the returns made
to the Stannary Court, which have been carefully corrected by those made.
to the Inspector of Mines, and to the Mining Record Office :-
1864
1865
·
1866
1867
1868
1869
1870
1871
•
1872
1873
Year.
Number of
Mines.
Quantity of
Tin Ore.
Average Price
per Ton.
Tons.
174
13,985
£ s.
60 17
a.
6
156
14,122
55 6
145
13,785
48 10 9
117
11,066
50 18
109
11,584
55 4 O
117
13,883
69 16 O
147
15,234
75 3 O
145
16,898
78 12 6
162
14,266
87 7 0
213
14,884
78 I O
The prices of Foreign tin, and a statement of the stocks on hand in each.
of those years, as they materially influence the value of the tin mines of
Cornwall and Devonshire, are given in the following table :-
Prices per Cwt.
Year.
Stock of
Foreign Tin.
Banca.
Straits..
S.
d.
S.
1864
1865
•
107 8
95 10
d.
106 I
92
5
Tons
2,970
3,287
cwts.
O
II
1866
85 2
82 6
3,149
8
1867
1868
•
91 7
88
O
2,565
I I
·
95
2
93 8
1,755
1869
128
6
126 3
1,516
1870
126 8
124 2
•
1,137
16
ã coir
8
1871
1872
1873
•
135 2
153
135 3 133 3
133 6
992
8
145 113
1,759
15
1,507
550
O
The actual production of the Dutch tin mines in each of those years was
as follows:
3 G
820
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Year.
Banca.
Billiton.
Total.
Year.
Banca.
Billiton.
Total.
Tons.
Tons.
Tons.
Tons.
Tons.
Tons..
1864
5,343
794
6,137 1869
•
4,483
2,424 6,907
1865
4,554
1,065
5,619
1870
4,672
2,858 7,530
1866
5,234
1,171
6,405
1871
4,320
3,190
7,510
1867
•
4,639
2,341
6,980
1872
4,352
3,456
7,808
1868
3,960
2,151
6, III
1873
4,480
3,264
7,744
Our importations of tin, in the form of ore, and as pure tin or regulus, in
the last two years, were as follows-the countries named being those from
which the largest quantities were received:
1872.
1873.
Tin Ore.
Metal or
Regulus.
Tin Ore.
'Metal or
Regulus.
Tons.
Tons.
Tons.
Victoria
Straits Settlements
India Dutch possessions
China .
New South Wales
Queensland.
6,095
I
Tons.
4,812
209
280
372
46
297
25
25
58
50
·
334
4
3,114
331
106
•
1,302
103
Tasmania
•
13
Peru
Chili
ΙΟΙ
18
448
671
387
79
157
114
The total imports being in-
1872, 1,024 tons of Ore, and 8,342 tons of Metal and Regulus.
1873, 5,612
""
7,791
""
""
This being an increase of 4,578 tons of ore, out of total 18,544 in 1872, and a
decrease of 552 tons of tin in the metallic or reguline state.
In 1872 we smelted in this country-
14,266 tons of British Tin Ore, producing
1,024 tons of Foreign and Colonial Tin Ore, producing
And received of Metal and Regulus
The total production of British, Foreign, and Colonial Tin being
In 1873 we smelted in this country-
14,884 tons of British Ore, producing
5,612 tons of Foreign and Colonial Ore, producing
And received of Metal and Regulus
·
9,560 tons of Tin.
642
8,342
18,544 tons.
""
9,752 tons of Tin.
3,650
7,791
21,193 tons.
""
The total production of British, Foreign, and Colonial Tin being
The loss in refining the regulus, and some of the Foreign tin, is not of
great importance, therefore it is not taken into account in either year.
The exports of tin of British production in 1873, and the two previous
years, were, according to Board of Trade returns—
In 1871, 114,201 cwts.
1872, 113,871
""
,, 1873, 115,946,,
The exports of tin of Foreign and Colonial production were—
In 1871, 41,196 cwts.
""
""
1872, 48,634
1873, 28,869
""
That is, of British, and Foreign, and Colonial tin, we exported—
In 1871, 7,769 tons.
""
1872, 8,124 tons, an increase of 355 tons.
""
1873, 7,250 tons, a decrease of 874 tons.
CHAP. I.]
THE DUTCH TIN TRADE.
821
This statement, which is as nearly correct as it is at present possible to
make it, will place before the reader the position of our tin trade in 1873,
and enable the tin miner to calculate his prospects in future years.
It must be remembered that, in addition to the tin which we have for a
long period been steadily receiving from Banca and Billiton, a new tin-pro-
ducing district of great value is being opened out in the Malacca Peninsula,
and that an English company are commencing operations in a large and
promising district of Siam, said to be rich in stream tin.
It will be seen by the table given below that the Banca and Billiton sales
have remained tolerably uniform for the five years ending 1881, but that the
Straits shipments have shown a rapidly increasing rate. During the past
three years large quantities of tin ore have been raised in Siam and the
Malayan peninsula, the principal portion of which has been sent to China :—
1877.
1878.
1879.
1880.
1881.
Tons,
Tons.
Tons.
Tons.
Tons.
Banca Sales
Billiton Sales
4,324
4,064
4,253
3,638
4,339
3,000
3,970
4,513
4,735
4,735
Straits Shipments
3,014
7,900
10,985
11,660
11,475*
The Australian production has been so large, and the cost of production
so small, that the importation of the tin from our colonies has tended to
reduce the prices of tin ore in this country very materially. The discovery
of stanniferous deposits in New Zealand and Queensland, which promise to
produce stream tin of high quality at a low cost, will certainly have the
effect of preventing any increase in the price of British tin. The returns
from the Australian ports, Sydney, Melbourne, and others, have been as
follows for the last ten years :—
Tons.
Year.
1872
1873
1874
1875
1876
150
2,990
5,800
7,210
8,392
Year.
Tons.
1877
9,093
1878
8,650
1879
7,426
1880
7,800
1881
•
9,000 †
SALES OF TIN IN BILLITON.
1877.
1878.
1879.
1880.
1881.
Piculs.
Average
price
Piculs.
per Picul.
Average
price
per Picul.
Piculs.
Average
price
per Picul.
Piculs.
Average
price
per Picul.
Piculs,
Average
price
per Picul.
February
10,000
April
June
45/1/
August
October
Florins.
46.87
10,000 46.42
10,000
10,000 42100
10,000
10,000 42.37 10,000
Florins.
Florins.
Florins.
Florins.
10,000 418
10,000 412
12,000 3842
13,000
6312
13,000 6033
10,000
41.22
32
12,000 450R
13,000 4326
13,000 562 R
13,000 5989
13,000
4720
13,000
6124
402/
13,000 4220
36.96
13,000 561
December
13,000 5802
13,000 5825
13,000
6129
13,000 66
10,000 43'47
12,000
41.63
13,000 621
13,000 6122
13,000 7512
The sales of tin in Holland, and of Billiton tin in Batavia, for the five
years ending 1881, will give a correct impression of the manner under which
the Banca tin reaches our manufactories.
* Those readers who desire any more detailed description and commercial account of the tin trade
should consult "A History of the Trade in Tin." By Phillip William Flower. 1880. (George Bell and Sons.)
"Banca tin is produced by convict labour in the island of Banca, from whence it is sent across to the
port of Batavia, in Java, for shipment to Rotterdam, where it is warehoused, and sold periodically by the
Some-
Trading Company. Billiton tin is raised by a private company in the Dutch island of Billiton.
times sold on the spot and sometimes sent to Holland for sale."-Flower's "History of the Trade in Tin."
3 G 2
822
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
1877.
1878.
1879.
1880.
1881.
Slabs.*
Average
price.
Aver-
Slabs. age
price.
Aver-
Slabs. age
price.
Slabs.
Aver-
age
price.
Price
Slabs.
per
50 kilos.
Florins.t
Florins.
Florins.
Florins.
January
19,800 43/1/1
18,300 401 19,479
March.
23,518
4231
20,900
40
23,346
May
22,400
42/1/1
20, 110
398/
23,426
14,988 511/
23,417
20,162 43
23,489
13
July
23,584
41'05
September
•
21,635
40100
19,613
24,200
39元
​23,300
35.8
23,059
•
November 24,717 40.95 23,817
39.6 23,500
555556
382 +8+
-ka-bolkoHI+HO
19,937 59 18,297
Florins.
53/1/1/0
58
528
58 1/1/0
20,214 57 23,653 544
20,608 49€/ 23,414
20,493 56 23,322
64
The only course open to the British miner for checking the importation
of Foreign and Colonial tin, appears to be the exercise of the strictest economy
in every branch of production. Into the mines labour-saving machinery
must be introduced, and on the dressing-floors every advantage must be
taken of such scientific knowledge as is directly applicable to the separation
of bodies of different specific gravity, one from the other.
The following general statement will be found useful in studying the
progress of tin-mining.
In
According to the charter of Edmund, Earl of Cornwall, the tin at this
time paid a duty of a halfpenny for every pound weight when coined.
the reign of Edward I. the duty was fixed at 4s. for every hundredweight
of coined tin. The dues upon tin in Devonshire paid to the Duke of Corn-
wall have been only at the rate of is. 6d. per cwt.
In 1213 the duty payable to the Earl of Cornwall was farmed for 200 marks
(of 13s. 4d. each) for Cornwall, about £175, and £200 for Devonshire.‡
In 1337, Edward the Black Prince being then Duke of Cornwall, the profit
on the coinage was at first 3,000 marks, and the price increasing it became
4,000 marks, about £3,500, which will represent a produce of 3,698 tons of
20 cwts.
In 1524 the profits of both counties were £2,771 3s. 91d.
In 1602 (the forty-fourth year of Queen Elizabeth) the coinage amounted
to £2,623 9s. 8d. in Cornwall, and £102 175. 9 d. in Devon.
In the reigns of James I. (1610) and Charles I. (1630) the produce, accord-
ing to Lysons, quoting "The Records of the Duchy of Cornwall," varied from
1,400 to 1,600 tons.
In 1742 the Mines Royal Company reported the average produce to have
been about 2,100 tons for several years.
From 1750 to 1779 the average produce in each year was about 17,000
blocks, the weight of each block being computed at 3'35 cwts. Converting
the blocks into tons, the mean average will be 1,763 tons per annum. From
a table produced by the late Mr. John Taylor we find that from 1780 to 1838
the mean average annual produce of tin was 21,132 tons.
For the years 1799, 1800, 1801 the Duchy of Cornwall received £9,620,
and in 1814 the revenues of the Duchy of Cornwall for tin was about £8,500.
In 1820 Cornwall produced 2,775 tons of tin.§
De la Beche gives a table from midsummer, 1837, to midsummer, 1838,
which shows the relative quantity and kind of tin produced.
* 1,000 Banca slabs weigh about 32 tons.
Lyson's "Magna Britannia," p. cclxxx.
† Average price per 50 kilos.
§ "Transactions of the Geological Society of Cornwall."
CHAP. I.]
Coinage towns.
Calstock
Truro
•
Hayle
Penzance
TOTAL OF TIN PRODUCED.
CORNWALL.
Grain tip.
Common tin.
393 blocks.
1,349585
8,952
5,334
12,423
823
Morwelham
DEVONSHIRE.
32.
•
674
Making a total of 29,321 blocks, or 5,130 tons, of which 1,545, or about
one-nineteenth, was grain tin, and 27,776 blocks, common tin.
The following table continues the statement of the annual production
from our tin mines to the nineteenth century:
In 1874 the production of Tin was
""
1875
""
1876
,, 1877
,, 1878
""
""
19
""
""
1879
1880
1881
""
""
""
""
""
1882
Tin Ore.
Tons.
Metallic Tin.
Tons.
•
14,039
9,942
13,995
9,014
13,688
8,500
•
•
14,142
9,500
•
15,045
10,106
•
14,665
9,532
•
13,737
8,918
12,900
8,600
•
13,043
8,694
Inspector's Return 12,157 tons
Streams
886 ""
It must appear to many that the attempt to estimate the total quantity of
tin produced from the stream works, and from the mines of this country,
since the commencement of the primitive process of searching the alluvial
deposits, must prove an abortive one. Under all the circumstances of
the case the result must at the first appear to every one as unworthy of atten-
tion. It is unhesitatingly admitted that the estimated production of tin,
previously to the Norman Conquest, can be little other than a probable
guess. It should, however, be stated that the researches of antiquarians
sufficiently warrant the expression of an opinion that the Phœnician mer-
chants carried, by the maritime and by the overland route across Europe, in
those early days only small quantities at a time. Judging from the existing
evidences afforded by the "Jews' Houses," and the slabs of tin which have
been discovered in various parts of Cornwall, we have evidence that
the smelting operations were on a limited scale. The ships which carried
the tin from this country were small, and we are informed that the mules.
on whose backs the slabs of tin were borne across Europe were rarely
weighted with more than one hundredweight of tin.
Until the fourteenth century we are unable to do more than guess at
production; but since then we arrive at an approximation sufficiently close
to enable us to state that upwards of three million tons of metallic tin have
been extracted from our stanniferous deposits :-
In the 500 years before Christ
""
500 years of Roman occupation
To 1066 The landing of William the Conqueror
""
1300 Edward I.
39
1500 Henry VIII.
1600
""
""
Elizabeth
1636 Charles I.
1740 Computation of Mines Royal Company
1834 William IV.
1860 Victoria
99
1880 Ditto
"9
•
50,000 tons.
50,000
100,000 ""
369,800
42,048
680, 100
30,000
235,000
""
""
""
""
""
202,000 ""
162,000 99
195,223
""
3,016,171,9
824
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Tin streams, and detrital deposits in general, are producing at this time a
very small quantity of black tin (tin ore). Some of that included in the follow-
ing table is really derived from tin mines, it being carried away with the
waste of the dressing-floors.*
PRODUCE OF TIN STREAMS.
1872. 1873. 1874. 1875. 1876. 1877. 1878. 1879. 1880. 1881
I
123456 78
Goonlaze
9
Gwythian
IO
Helston
II
Lelant
12
Letcha Foreshore
913
13
Looe Pool.
2 19 3 18
4 14
8
T. c. T. C.
T.
Bushorne's Stream
C. T.
68
T. c.
C.
T. c.
I.
C.
T. c. T. c.
T. C.
2 I
I I
I II
Carbis Beach
Chapel Porth
Cleggar Porth
Coombe
Darley Leat
Excelsior Stream
0 8
::
0 40 13
о
2
I II I 4
9 O
Ο ΙΙ
O 17
0 7
I 16
•
4 7 I 9
69
3 I
I 14 5 7
4 8
0 5
9
0432
21 12
0
O
9
12 I
5
14 19 6 5 5 4 4 14
5 II
4 3
4
I 12 I 3
2 18
5
3 0
5 10 6 O
6 19
O 13
io
24 10
12 II
12 II IO I 22 16
..t
14
Menardarva Stream
9 13
15
Mill Tin
دو
4 12
•
16
Nancemellin
""
3 15
17
Nanjulian
0
3
::
18
Perran Beach
2 17
2
9
• •
0 5
19
Perran Porth
2 19
O 12
20
Perran River
O 12
0 9
I
21
Porthledden Sands
22
Polberro Cove
16
•
I
I
168
нон
I
9
4
∞
•
23
Porth Towan
2
I
•
I 6
0 6
O
24
25
Restronguet Stream
Roseroggan
16 II
18 13
2 2 2
26
Rosewarne
""
27
Short Horn Beach
28
Trevellas
·
29
Trevaunance
""
4 II
9 2
7 13 14 12
o 16
O 12
3 13
4 4 4 18
4 2
6
O
30
Tolbesco
>>
15
7 O
I
O
9
2
7
I
6 I
5 136
Ο ΙΙ
2 18
O 15
+
COPPER.-It has been shown in the historical sketch that copper was not
unknown to the early inhabitants of these islands; but there are many reasons
for supposing that all, or nearly all, that was used by the Britons was im-
ported from the Continent, and this was continued until the early part of
the sixteenth century. We have evidence that the Romans smelted some
* The produce of the "Red River" and other rivers collecting the waste from the dressing-floors
of the tin mines between Redruth and Camborne is not included in the above table. In the five years
ending 1881 the following quantities were obtained from this source:-
Year.
1877
1878
1879
1880
1881
•
Quantities.
Tons cwts. qrs. lbs.
689 II 2 O
736 II 2
O
762 14 2 15
818 7 3 7
909 I I O
Value.
S. d.
20,858 0 6
19,433 15 4
21,876 I I
•
36,810 10 6
35,283 O O
It has been frequently argued that this large quantity of tin ore should not-if the dressing arrangements
were perfect-be allowed to flow away from the dressing-floors as waste. On the banks of the Red River
there are seventeen separate establishments fitted with a good description of machinery, and on the river
flowing from Carn Brea and Tincroft, joining the above at Tehidy Mill, there are eight other sets of
dressing machinery at the present time. There may be a few small streams occasionally worked. Some
tin is still obtained from the China Clay Works, and at intervals, discoveries are made of detrital tin in places
where there was no suspicion of the existence of such a deposit. During the year 1882 a small quantity
was discovered in some land in the parish of St. Paul, on the western side of the Mount Bay.
+ The later returns from Looe Pool include the streams in Wendron, Sythney, Breage, &c.
:
CHAP. I.]
EARLY PRODUCTION OF COPPER.
825
copper from British ores during their occupation. Dr. Percy, in his
"Metallurgy," says: "I am informed by Mr. Albert Way and Mr. Franks,
the eminent archæologist, that lumps of metallic copper, more or less
rounded, have been discovered in different parts of the country, but always
in association with articles of bronze. Mr. Franks showed me one of these
lumps, which evidently had been melted, and which, on examination in the
Metallurgical Laboratory, proved to be practically pure copper."
It will be remembered that Professor Phillipst says: "There is, I
believe, no instance of a single bit of pure tin or pure copper being found
with the numerous 'celts' which occur in so many parts of England."
Cæsar informs us that the brass-meaning brass or bronze indifferently
―used by the natives of Britain, was imported. It is tolerably certain that
bronze vessels, and tools, and weapons, were made in this country; but the
probability is that the copper used by the Britons in their manufacture was
imported.
In Anglesea-where the copper ore came up to the surface-and in
some other parts of North Wales, there is evidence that copper was smelted
at an early period by the Romans, or by the Celtic slaves under their
direction. The cake of copper found at Caerhem or Caer-Hen, near
Conway, described by Pennant,‡ proves that copper was procured in these
islands, but the quantity must have been quite insignificant. We really
have no evidence, before the time of Elizabeth (1558), on which any depen-
dence can be placed. Then, in all probability, the German miners introduced
by that queen first worked our copper mines. These mines have really
only risen into importance since the commencement of the eighteenth
century. From that period until about 1852, there was a steadily increasing
annual rise, the quantity produced in that year being nearly 209,305 tons.
The produce of the Cornish copper mines regularly declined from that
year, until in 1881 we find the quantity sold at the Ticketings is reduced
to 40,584. It will be seen, from TABLES printed in the Appendix, that
commencing in 1726, with a produce in the mines of Cornwall of 5,000 tons,
the quantity increased steadily to the year above named. The total pro-
duction of copper ore in the United Kingdom, and of metallic copper
obtained from native ores, shows that in 1856 our copper mines produced
218,659 tons, yielding 14,775 tons of copper, whereas in 1880 all our mines
gave us only 52,118 tons of ore, yielding 3,662 tons of metal.
The following table, showing the variations in the average prices of
Cornish copper ore, will be found to be of importance to our argument.
Year.
1700
1730
1750
1779
1797
£ s. d.
2 10 OS
7 15 10
7 6 611
£ s. d.
ΙΟ I IO
8 15 4
Year.
1805
1814
1822
•
1832
6
I 6
1842
6 7 O
* (
5 16 o
7 17 8
6 4 4
Metallurgy: the Art of extracting Metals from their Ores, and adapting them to various Purposes
of Manufacture." By John Percy, M.D., F.R.S.
"Thoughts on the Ancient Metallurgy and Mining in Brigantia and other Parts of Britain." By
John Phillips, F.R.S.A.
I See p. 41.
§ "Borlase's "Natural History of Cornwall."
In 1758, Borlase says: "Yellow ore now sells for a price between ten and twenty pounds per ton."
This would have been ore of highpercentage produce.
826
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
The low price of copper ore in 1779 arose from the large quantities of
copper thrown into the market from the mines in Anglesea, which up to
1784 were said to be producing 3,000 tons of copper annually.* About the
same period the copper mine at Ecton Hill, in Staffordshire, was discovered:
its most productive period being about 1780.
It is not necessary that the evidence already given should be re-stated.
Pryce tells us that, in 1737, 9,000 tons of ore were raised. The approximate
value of the copper obtained in 1760 was £66,825. By comparing this with
the value of the ores raised in 1837 we find an increase in the same of four
times and two-fifths nearly (De la Beche). We have seen that in 1877 the
quantity of copper raised in Cornwall reached its maximum, 14,091 tons.
The copper mines of Devonshire produced in 1801 1,078 tons of ore.
This quantity steadily increased until, in 1837, 6,328 tons of ore were raised.
A little copper has been raised from the neighbourhood of Doddington,
on the north-east of the Quantock Hills. Twenty-eight tons of copper were
obtained in Somersetshire in 1821; and Mr. Leonard Hornert drew attention
to green and blue carbonates of copper worked in the Red Sandstone
Conglomerate down upon the lode in the grauwacke beneath.
Shafts have been sunk near Minehead without any profitable return;
and for the last half century no copper ore of any consequence has been
produced in Somersetshire.
The fact of there being a lawsuit, between Elizabeth and the Earl of
Northumberland, relative to a copper mine at Keswick, proves that it was a
mine of some importance; indeed, 4,000 men are said to have been employed
there.‡
Camden says much good copper was for a long time made at Keswick,
where the works were established in 1566, and Newland, where in 1709 the
miners found eleven veins, but we know nothing of their value; but in 1671
Webster§ wrote, "Now the Work is quite left and decayed, yet I am informed
that some do now melt forth as much very good copper, as serveth them to
make half-pennies and farthings."
Edward III., in the fifteenth year of his reign (1341), granted to a
company of nine adventurers, who were headed by Richard, Duke of
Gloucester, certain copper mines in Alston Moor, and near Richmond,
in Yorkshire. That the quantity of copper ore raised at this period was
comparatively small appears from the fact, that copper was imported into
England from Hungary and Sweden, and that Calamine was exported as
ballast.
The valuable work of the late Colonel Grant Francis || gives several
curious letters, the substance of which has been already quoted, which show
that very small quantities of copper ore were raised in Perranzabula, and
from two or three other mines in Cornwall, and smelted there in 1583. The
following quotations appear to prove this :-
*Plot's "History of Staffordshire."
"Transactions of the Geological Society of London," vol. iii.
"Some Account of Mines, and the Advantage of them to the Kingdom." By Thomas Heton, M.A.
London: 1707.
§ "Metallographiæ," &c. By John Webster. London: 1671.
Francis.
"The Smelting of Copper in the Swansea District from the Time of Elizabeth." By Grant
CHAP. I.]
EARLY COPPER MINES.
827
I.
1. "Y't you have not above 50 tons gotten in all."
2. "I measured and received this last week at Logan 10 tons of good
and clean sorted copper ore." (1584.)
3. "We have in readiness as much copper roste, and blake copper, as
will make 20 tonne of good fine copper." (1586.)
4. “The 14th October, 1585, came John Bwaple, one of Wales, w’h his
bark for a frayght of copper owre, and did deliver him, the 21st October,
15 tonn. and 8 hundred of copper owre for Wales. * * I received his
fraight at St. Ives, and for my lyffe I could not get any owre from St.
Yeust." (St. Just.)
These statements sufficiently show that, at the period named, the pro-
duction of copper in Cornwall was small. We learn from Pryce,* that the
rich black oxide of copper was, in the beginning of the eighteenth century,
thrown away by the tinners, under the name of poder, and that several
thousand pounds' worth were formerly washed down into the sea from Old
Poole mine. Mr. J. Carne, writing in 1824,† says that for fifty years the
miners of Wheal Jewell threw away these rich ores (oxide of copper)
in ignorance of their value. The author was informed that the family of
the Williams's, who were then working Tresavean mine most profitably for
tin, caused all the workings to be given up "because they had come to the
yellows" (copper pyrites, yellow copper ore).
Dr. Borlase says that the copper pyrites was always known to the tin-
miners as poder, but De la Beche‡ with much reason says: "As poder means
dust, which would agree with the appearance of this friable ore (the black
oxide of copper), it may be questionable how far Borlase may have been
correct in stating that yellow copper ore was thus named. As poder has
this meaning, may not the name be a provincial manner of pronouncing the
English word powder ?
The same authority, in his "Natural History of Cornwall," states that
Mr. Beauchamp of Gwennap, "at this time covenanted to sell all the copper
which he should rise out of a well-stocked mine for twenty years at £5
per ton, and the ore at Relistian, in Gwinnear, was covenanted for at £2 10s.
per ton."
There is not much doubt but that copper ore was found in Cornwall
associated with the tin from a very early period. Native copper was some-
times found at shallow depths, and we are told that a small parcel was sold
to the Cornish Copper Company, from a deep situation in Cook's Kitchen.
About 1690, some speculators came into Cornwall from Bristol, and pur-
chased copper ores at the rate of £2 10s. to £4 per ton. Mr. Thomas Coster §
of Bristol, with other persons, are said to have become adventurers in the
Cornish copper mines. This Thomas Coster was lessee in 1746,with Partners,
of the copper works built on lands leased by the last Lord Mansell, known as
the "White Rock" Copper Works.
This Mr. T. Coster appears to have introduced into Cornwall a better
system of draining the mines, of dressing the copper ores, and assaying them.
* "Mineralogia Cornubiensis.”
+ "Transactions of the Geological Society of Cornwall,” vol. iii.
I " Report on the Geology of Cornwall and Devon."
§ De la Beche calls him John Costar; Colonel Francis, always Thomas Coster.
828
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
He bought, it is said, 2,100 tons of copper from North Roskear mine, 1,400
of which had been lying unsold on the mine for years. He is said by
Pryce to have made a profit of not less than £60,000 in a few years by his
speculations in copper.
From this time we obtain a tolerably correct return of the copper ore
raised from the Cornish mines.
The average produce of the copper ores smelted from all the mines of
Cornwall for about sixty years,* appears to have been as follows:-
Years.
1771
1781
1791
1300
1801 to 1810
1811 1820
""
""
1821 1830
1831 1837
""
Tons of Ore.
Tons of Copper.
27,896
3,347
28,749
3,459
Records lost
53,981
5,187
67,532
6,059
78,569
6,602
114,040
9,143
142,785
11,637
Produce per Cent.
12
•
12
91%
9
8/31/1
8
8/31/18
Sir Charles Lemon-who was ever anxious to place the mines and the
miners of Cornwall in a more satisfactory position than that which had
prevailed for so long a time, communicated his paper to the Statistical
Society, in the hope of being enabled to show the necessity of keeping
records of progress-writes thus, with especial reference to the contemplated
Mining Record Office": "The sketch I here offer is slight, and some
of the tables are avowedly imperfect, but they will shortly be replaced by the
results of an inquiry taken up at the suggestion of the British Association,
and now in the hands of a person having far better opportunities than I
possess of obtaining information."
<<
About 1768 the great mines in Anglesea were discovered and actively at
work. In 1784, 64,800 tons of copper ore, about 3,000 tons of fine
copper, are stated to have been produced annually from Mona and Parys
Mountain mines. To 1798 the profit is given as £2,257,291 sterling.
For more than fifty years the Ecton and the neighbouring mines in
Staffordshire are said to have yielded a profit exceeding £70,000 per
annum; and Mr. Walter Eddy states that "coming back to recent times
(1777), I find, from documents left in the Mine Office, that in twenty years,
between that date and 1797, 44,769 tons of copper ore were raised, giving
on the average 15 per cent. of copper, and realising £12 a ton.” This
copper mine was known to Dr. Plat, who wrote in 1686. Farey tells us
that "most immense quantities of copper were extracted before 1770."
In 1781, he says, "the copper ore seems nearly or quite exhausted."
The copper mines near Keswick and other places in the northern counties
were worked for several years, as, in 1684, "Letters" were published asking
"What quantity of copper is left upon the place?" that is, in the mines
around Keswick.
Copper ore was obtained from the mines in Wales and from those in
Scotland, but there was never any large production recorded.
The Mucross mine in Ireland produced for some time 200 tons of copper
ore a month. The total value of that which was raised in four years was
£80,000.
* "Statistics of Copper Mines of Cornwall." By Sir Charles Lemon, Bart., M.P. ("Journal of
the Statistical Society of London,” vol. i. p. 65.)
CHAP. I.]
ANGLESEA AND STAFFORDSHIRE COPPER.
829
Tables, compiled by the author, were published in the "Memoirs of the
Geological Survey," giving the production of copper from all the mines in
Cornwall for the years 1845-47, with the average price per ton-the
"standard" and produce. The following is an abstract of these tables:-
Copper Ore.
Tons.
162,557
1845.
Copper. Produce.
Tons.
12,883
1846.
Copper Ore. Copper. Produce.
Tons.
Tons.
150,431 11,850
7
1847.
Copper Ore: Copper. Produce.
Tons. Tons.
155,985 12,754 81
From the commencement of the public sales of copper ore at Swansea
from 1804 to 1847, the total production was :—
Copper Ore.
From the Welsh Mines
The Sale from the Irish Mines
Tons.
53,7ΟΙ
363,339
22,521
Ticketings from English Mines, from 1815 to 1847, being only
Accompanying these tables there was a diagrammatic chart showing the
produce of copper ore in Cornwall for a century, and the fine copper produced
during sixty-five years :—
In 1744 the copper ore was about
,, 1747 it fell to
,, 1757 it rose to
7,000 tons.
4,700 ""
16,000 ""
And, with very few undulations, the production steadily increased until in
1840 it rose to 155,000 tons, falling back in 1843 to 135,000 tons. The fine
copper, in 1771-the earliest reliable record—was 3,500 tons, which in 1830
rose to 12,000 tons, and for several years oscillated between that quantity
and 9,500 tons. Between 1771 and 1844 we have records of the copper raised
in Cornwall, which amounts to about 146,000 tons.
Mr. G. R. Porter* gives the copper raised in the United Kingdom from
1820 to 1834 as follows:-
Year.
1820
Tons.
Year.
Tons.
Year.
•
8,127
1825
10,358
1830
•
Tons.
13,232
1821
•
10,288
1826
I1,093
1831
14,685
1822
1823
1824
•
•
11,018
1827
12,326
1832
14,450
•
9.679
1828
•
•
12,186
1833
13,260
•
•
9,705
1829
•
12,057
1834
•
14,024
Since 1834, says Mr. Porter, the produce of copper smelted from English
ore cannot be accurately distinguished from that of Foreign origin.
The general state of the copper mines of Cornwall for seven years,
ending 1798,† appears to have been as follows:-
The Adventurers' ore in that time amounted to a value of .
The total cost of working
•
£2,237,291
2,195,123
42,168
The net profit for 7 years
Appended will be found several tables showing the actual production
of copper ore from the United Kingdom and the metallic copper obtained
from it since 1856. These tables convey to those who are interested in the
subject all the available information. An attempt has been made to
estimate, as in the case of tin, the total quantity of copper ore which has
been obtained by mining in these Islands. From the circumstances that
copper ore has been obtained from mines in every part of the country, and
that some of the ore has been smelted at local works-sometimes on the mine
-that portions have been sold at the public sales (Ticketings) in Cornwall
* "The Progress of the Nation in its various Social and Economical Relations from the Beginning of
the Nineteenth Century." London: 1847.
+ "Copper Mines and Copper Trade Report, 1799."
830
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
and at Swansea, and other portions purchased by private contract, it has
been found almost impossible to arrive at any final result which would not
be more or less delusive.
An attentive examination of all available authorities and of such
collateral evidence as can be obtained, leads to the belief that the following
may be accepted as a fairly correct approximation to the extent of exhaustion
which has been going on in the copper mines of the British Isles :—
a During the Roman Occupation ore was probably raised, which produced
b To the time of Edward III. (1341)
c To the reign of Elizabeth, and after the introduction of German miners (say
1600)
d To the beginning of the Eighteenth Century
e To 1775-Copper ore raised 693,500 tons
ƒ To 1800
""
1,450,000
g To 1835
h In 1855
*
""
"9 3,150,000 ""
""
""
† 4,370,000
""
•
Tons of
Copper.
5,000
15,000
47,000
100,000
37,500
78,500
•
167,000
218,000
From this period to the present time the annual returns have been as
follows:-
COPPER ORE AND COPPER FROM THE MINES OF THE UNited Kingdom.
Copper Orc.
Tons.
218,659
215,689
218,698
236,789
362,696
Copper.
Tons.
Year.
•
14,775
1869
Copper Ore.
Tons.
129,953
Copper.
Tons.
•
8,291
•
•
14,375
1870
106,698
7,175
•
·
14,456
1871
97,129
6,280
•
•
13,594
1872
91,893
5,703
15,968
1873
80,188
•
5,240
15,331
1874
78,521
•
•
4,981
14,843
1875
71,528
•
•
4,323
14,247
1876
79,252
•
4,694
13,302
1877
73,143
4,486
11,888
1878
56,094
•
•
3,952
•
11,153
1879
51,035
3,462
10,233
9,817
1880
52,118
3,662
1881
52,556
3,875
Year.
1856
•
1857
•
1858
•
1859
1860
•
1861
·
312,487
1862
•
224,417
1863
200,947
1864
214,604
1865
•
198,298
1866
•
180,378
1867
•
1868
158,544
157,335
•
•
It will be interesting and instructive to give a statement, here compiled
from actual returns furnished to the Mining Record Office, which will
show the duration of our copper mines. During thirty years the number
of Cornish copper mines selling upward of 5 tons of copper ore annually
appear to have existed-
35 mines lasting 20 years and upwards.
40
""
""
""
""
31
114
10 years, but under 20 years.
5 years, but under 10 years.
less than 5 years.
The highest average percentage produce of the 220 mines for the entire
period above named was 73.
The lowest produce of one mine was 23.
The highest produce from one mine was 203.
* Mr. Porter ("Progress of the Nation, 1847") gives the value of tin and copper raised in Cornwall at
different periods during the present century :-
1801. Tin and Copper
1806.
""
1811.
""
1816.
""
£731,035
1,074,872
901,978
925,083
1821. Tin and Copper
1826.
""
1831.
""
1834.
""
£871,562
1,137,045
1,106,935
1,209,762
"The total quantity of copper ore raised in Ireland I believe to approximate at present (1845)
closely to 25,000 tons per annum." ("The Industrial Resources of Ireland." "By Dr. Robert Kane, M.D.)
CHAP. I.]
COPPER PRODUCED IN COUNTIES.
831
The production of copper in all parts of the United Kingdom was
carefully obtained for the three years 1859, 1860, and 1861, The table given
below shows the quantities produced at a period when copper mining was
fairly successful.
NUMBER OF
MINES.
COPPER Ore.
FINE COPPER.
COUNTIES, &c.
1859. 1860. 1861.
1859.
1860.
1861.
1859.
1860.
1861.
ENGLAND AND WALES.
Tons.
Tons.
Tons.
Tons.
Tons.
Tons.
Cornwall
121
96 97
Devon.
ΙΟ
20
183,498
182,534
181,594
12,202
12,210
11,663
20
Cumberland and Lancashire.
Anglesey
•
Carnarvon
•
Cardigan
•
3
Montgomery
Isle of Man.
Cheshire
I
I
I
4×
7352 H 3H
6235
532 MET
3,225
2,628
2,331
624
184
8,386
7,713
8,792
448
416
486
2,252
2,623
2,079
99
114
1888888
109
35
75
67
3
5
I
115
8
35
753
1,485
26
53
93
I
I
10,27
227
335
427
155
215
147 137 139
208,021
196,553
196,798
12,829
13,137
12,747
Estimated Value.
Total for England & Wales
£
1,379,801
£
£
£
£
£
1,259,660 1,118,810 1,532,996
1,414,745 | 1,307,842
QUANTITIES.
Cork.
Tipperary
Waterford
Wicklow*
IRELAND.
Tons.
Tons.
Tons.
Clare
•
23H MH
3
4
4,536
6,466
7,350
Tons.
474
Tons.
Tons.
651
780
298
29
I
3
I
£6
1 3
I
6,090
7,765
6,670
635
3,238
4,180
1,641
106
75
756
667
586
27
96
4
IO IO
8
14,258
18,411
15,661
1,248
1,993
I,474
ESTIMATED VALUF.
Total for Ireland.
√√3,171
108,171
£
167,540
£
141,263
f
125,215
£
206,564
£
151,232
QUANTITIES.
14 23
20
Ions.
14,510†
Tons.
21,732
Tons.
Tons.
Tons.
19,028+
693
838
I ons.
I, IIO
Copper ore purchased by
private contract from
sundry districts not in-
cluded above.
ESTIMATED VALUE.
f
:
18,863
£
79,983
£
£
£
f
104,654 76,489
84,952
113,406
TOTAL QUANTITIES.
Tons.
Tons.
Tons.
Tons.
Tons.
171 170 167 236,789
236,696
231,487 15,770 15,968
Tons.
15,331
Total for England, Wales,
TOTAL ESTIMATED VALUR.
and Ireland
:
£
£
£
£
£
1,706, 261
1,506,835 1,507,183 1,364,727 1,734,700 1,706,261| 1,572,480
The following table will show the average percentage produce of the
mines with reference to the length of time during which they continued at
work :-
* In addition to these copper ores, some copper is separated from the iron pyrites of Wicklow.
† Including some iron pyrites from which copper is separated.
832
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
PRODUCE OF FINE COPPER.
35 Mines at 40 Mines at 31 Mines at
work up- work
work upwards of 10 wards of 5
up-
wards of 20
|
Years but Years but
Years... under 20.
under 10.
114 Mines
at work
less than 5
Years.
8/1
Average percentage produce of fine copper
Highest average percentage produce of a single mine
Lowest average percentage produce of a single mine
Number of mines producing above 25 per cent. of copper
""
""
""
""
""
""
""
""
•
15 per cent. of copper
Io per cent. of copper
5 per cent. of copper
less than 5 per cent. of copper
47-
78
7}}
138
14
148
26香
​5/1
2공
​4
2
4
2
13
32
34
29
70
I
2
| | N
22+30∞
AVERAGE PRICES, Produce, and Standard of Cornish COPPER ORE, from 1872 to 1881 inclusive:-
Year.
۵۰
Average Average
Price.
Average
Standard.
£ s. d.
Average Average
Average
Year.
Price.
Produce.
Standard.
Produce,
£
s.
1872
4 13
1873
4
1874
1875
4
5
1876 4 17 C
is m∞ mo
d.
£
S.
£ s. d.
6
114 17
1877
4 6
61
103 3 0
6
IIO
97 16
IIO O
1878 3
90 15
1879 3 86
86 14
1880
4 4
95 O
113 8
1881
4 5 6
94 8 0
The annual returns from the copper mines of Cornwall and Devonshire
are given in the Appendix. The copper ore obtained in other parts of the
United Kingdom is shown in the following table, which gives the produce, in
alternate years, of the copper mines beyond those of the West of England:—
ENGLAND.
CHESHIRE
LANCASHIRE
YORKSHIRE
CUMBERLAND
1871 1873 1875 1877 1879 1881
Tons. Tons. Tons. Tons. Tons. Tons.
8,608 8,122 8,236 | 6,288
646 108 514
Alderley Edge
Coniston
1,423
1,392 1,873
|
•
·
Merrybent
ΙΟ
72
Caldbeck Fells
Rough Tengill
300
271
}
86
146
Stow Crag
Ecton .
•
II
I
STAFFORDSHIRE
I
I
WALES.
MONTGOMERYSHIRE. Nant-y-Ricket
CARNARVONSHIRE
•
DENBIGHSHIRE
MERIONETHSHIRE
Great Gias
Great Dyliffe
Moel-fadian
Severn
Drws-y-Coed
Symdde Dylluan
Tan-y-Bwlch
Derwen-Deg
Carnarvon Consols
•
. Dyffryn, Mid and South
Glasdir.
Blaen Calan.
CARDIGANSHIRE
•
Darren, South
ANGLESEA
Glog-fawr
Cambrian'
Cwm Erfin
Parys Mountain
Do., Precipitate
Mona
·
Do., Precipitate
Parys, East.
ISLE OF MAN. Bell Abbey, &c.
Brada Head.
•
Gt. Laxey
Rushen
I
5
55
18
26
| 1
1 1 1
2
200
140
100
60
150
30
199
38
1
|
29
244
333
587
25
20
|
52
ΙΟ
156
16
78
7
ΙΟΙ
79
192
156
100 300 67
13
2,507 1,938 2,704 2,153
•
•
168
3,000
I20
1,628
205 150
600 1,040
180
100
863
766 3,804
297
400 270
202
22
[ 1 ]
100
•
•
80
·
60
| |
CHAP. I.]
COLONIAL AND FOREIGN COPPER.
1871 1873 1875
1875 1877 1879 1881
1877
Tons. Tons. Tons. Tons. Tons. Tons.
2,188 1,974 2,529
| |
IRELAND.
Berehaven
Ballycummisk
Ballygaham.
Do., Precipitate
Cooshen
Cronebane
Do., Precipitate.
Knockmahon
Tigrony, Precipitate
Ballymurtagh
Do., Precipitate
Errisbeg
SCOTLAND.
•
Sandlodge (Shetland)
•
•
•
576
301
18
32
46
ΙΟ
IO
II
9
I
847 1,962 30
3
2,076 1,143
22
23
29
70
90
8
155
17
314
| |
9
29
42
76
29
226
| | |
| |
40
778
833
Alderley Edge is a deposit of copper in Sandstone, the produce being
very low.
The mines of Anglesea are remarkable for a curious com-
pound ore known as "Blue Stone," and a similar ore has been found in
Wicklow, Ireland. The quantity of this raised being as follows:-
Parys Mountain
150
1871
1873
1875
Mona Mine
•
""
""
""
•
200 tons.
•
414
500
""
1879 ·
Mona Mine
•
548
•
. 1,532
368
""
The Irish mines returned
Ballygaham, 1,039 tons.
Cronebane, 2,290 tons.
Morfa Du
Connoree, Wicklow
in 1879 cupreous pyrites as follows:
| Tigrony, 3,249 tons.
These ores are chiefly
These
The total value of these ores being £5,139.
valuable for the sulphur which they contain; they also contain about 2 per
cent. of copper, a little silver, and traces of gold.
A satisfactory idea of the real condition of the copper trade of this
country will be formed by studying the following table, which gives the
quantity of metallic copper obtained from various sources during the past ten
years, Colonial and Foreign, in addition to that raised from our own mines:-
1871 1872 1873
1873 1874 1875
1876
1877 1878 1879 1880 1881
Tons.
Tons. Tons. Tons. Tons. Tons.
5,832 2,512 2,374 1,949 1,400
Tons. Tons. Tons. Tons. Tons.
Colonial and Foreign
ores sold at Swansea 3,650 3,077 3,489 4,847 3,743 5,399
Colonial and Foreign
contract (estimated). 6,080 5,150 6,746 5,297 | 6,340 5,850
ores sold by private
Colonial and Foreign
regulus and precipi-
tate sold at Swansea
96 431 618
Colonial and Foreign
750 832
30,750 27,914 12,898 7,796 7,110
regulus and precipi-
tate sold by private
contract (estimated). 5,924 4,630 3,085 8,750 16,140 15,762
Pyrites producing
•
Copper (burnt ore)
Precipitated copper ob-
tained from cupreous
pyrites
•
7,900 8,500 12,800 9,000 9,600 15,000
17,000 14,443 14,158 15,000 14,000
13,173 21,653 20,500 19,973
Totals 23,650 21,788 26,738 27,894 36,573 42,843 53,582 58,042 51,083 45,245 42,483
•
* The blue stone occurring in Anglesea contains sulphide of copper, zinc, and silver lead. That
which occurs in Ireland is a compound of equal parts of sulphide of lead and zinc containing silver.
834
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
When we learn from the table of the production of copper ore from
British mines, and see that our industries for the years 1878 to 1881 did not
exceed 4,000 tons of metallic copper, it will be evident that the present
depression of our copper trade is due to the large importation of copper
from our Colonies and from Foreign countries.
In addition to the above, old copper for re-manufacture, unwrought and
part wrought, were also imported. The following table gives the particulars
of these,—with the amount of copper ore and regulus, according to custom-
house returns,—and the value of the imported copper manufacture :-
Ore.
Regulus.
Value of
Old for re-
Unwrought and
manufacture. part Wrought. Manufactured.
Copper
Year.
Tons.
Tons.
Tons.
Tons.
£
1872
43,656
28,779
731
47,669
71,278
1873
50,769
27,908
743
34,535
61,662
1874
47,866
28,424
1,309
37,754
86,211
1875
53,663
32,906
I,497
39,728
72,670
1876
74,966
27,904
39,145
1877
93,457
33,701
39,743
1878
103,945
30,410
3,293
39,360
12,631
1879
87,829
45,930
2,866
40,670
45,763
1880
100,420
45,055
3,162
36,509
94,296
1881
102,040
44,216 '
32,170
1
British Copper Exported.
Unwrought, Wrought, and
Mixed Metal.
Foreign and Colonial Copper
Re-exported.
Wrought and part
Wrought.
Year.
Cwts.
Value.
Cwts.
Value.
1875
735,709
£3,237,529
14,689
£1,258,536
1876
709,889
2,934, 191
17,234
1,378,383
1877
798,615
3,059,909
14,157
1,036,970
1878
888,842
3,096,836
1879
970,168
3,071,300
17,837
1,103,595
1880
973,274
3,315,416
14,895
998,880
1881
1,025,272
3,438,555 13,790
876,367
The copper production in the United States of America has shown a
steady increase from 1872. This table has been compiled by Mr. James
Duncan Smith, one of the directors of the Arizona Copper Company
(Limited), published in Engineering, June 8th, 1883.
1872
1873
1874
1875
1876
1877
28,000,000 lbs.
1878
31,000,000 ""
1879
34,000,000 ""
1880
37,000,000 ""
1881
40,000,000 ",
1882
42,000,000 ""
43,000,000 lbs.
46,000,000,
57,000,000,,
70,000,000
88,000,000,
The consumption of copper in the United States is given-
In 1872
1882
""
34,000,000 lbs.
77,000,000 ""
This increased consumption has been due to the manufacture of wires
for electrical purposes. At first it was necessary to import copper for their
own use to the United States, but for some years no importation has taken
place.
Price in 1872
In 1882, highest price
lowest price.
35 cents.
201 ""
17 ""
ر اتاحت جبر
CHAP. I.]
PRODUCE OF LEAD AND SILVER.
835
Our principal imports for each of the five years to 1881 have been
from the Cape of Good Hope, British North America, Chili, and other
countries, as follows:-
Copper Ore.
Tons.
Regulus and
Precipitate.
Unwrought and
part Wrought.
Tons.
Year.
1877
115,466
1878
102,945
1879
87,829
1880
1881
99,849
102,640
Tons.
33,701
33,410
43,930
45,001
44,216
40,216
39,360
46,670
36,509
32,170
This continued increase in production from the countries named, and
from others where recent discoveries of great value have been made, renders
it improbable that our native copper mines can be expected to prove profit-
able for some time to come.
LEAD AND SILVER.—Both these metals were probably known to the
Britons before the invasion of Julius Cæsar. The evidences given show that
lead was worked by the Romans rather extensively in many parts of Britain.
The pigs of lead found in England and Wales, already described, having
Latin inscriptions impressed upon them; with often the statement that the
silver had been recovered from the poorer metal, show that the Romans were
both miners and metallurgists. Roman mines and scoria are found on the
Mendip Hills, Somersetshire, in Derbyshire, in Shropshire, in Northumber-
land and Cumberland, and in the Lake District.
The Romans used lead largely: they made tanks for water of that metal
and pipes to distribute that useful fluid. They buried their dead in leaden
coffins, and even lined some sepulchres with it. They must therefore during the
period of their occupation have used large quantities of lead: it would be a
random guess to say what quantity. Cicero writes to Atticus, saying there
was not a scruple of silver in the whole island.* Cicero's knowledge must
have been very imperfect, since Strabo reckons gold and silver amongst the
products of Britain. In the time of Augustus silver was coined in Britain,
and this was no doubt obtained from the lead ores of these islands.
Lister states that he proved the existence of silver in the lead of at least
thirty mines.† The lead ores of Shropshire and Derbyshire contain less
silver than those from any other mining district. Dr. Watson‡ says there
were in his time annually smelted in Derbyshire ten thousand tons of
lead ore, but he adds in a note, "This estimate I have reason to think
too high.” He then informs us that a cubic foot of the lightest of the
lead ores of Derbyshire weighed 6,565 ounces, and the heaviest 7,636
ounces. The mean weight of six pieces of this ore may be expressed by
7,342 avoirdupois ounces, whereas the Doctor estimated the weight of a
cubic foot of lead ore from the Isle of Man as 7,115 ounces. It is a fact
worthy of note that the mines of Mid-England, extending up to Shropshire,
contain but little silver, but as we advance into Wales we find the quantity
considerably increasing. For example, the produce of silver from some of
the mines of Cardiganshire has been as follows:-
Cwm-symlog
Darren Vawr
Llanfair Clydogau
•
40
35
ounces to the ton of lead.
""
""
60 to 80 ""
"
* "Etiam illud jam cognitum est, ne que argenti scrupulum esse ullum in illa insula."-Epist. ad
Atticus, 1. iv. E. xvii.
Lister de Fontibus," chap. ii.
"Chemical Essays," vol. iii. Third edition. By R. Watson, D.D., F.R.S.
3 H
836
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Several of the lead mines of Cornwall and Devonshire have proved to be
very rich in silver; the largest quantities separated from the argentiferous
galena being from the following mines :-
CORNWALL.
DEVONSHIRE.
100 ounces to the ton of lead. Bear Alston Mines 102 to 120 ounces to the ton of lead.
""
""
""
""
South Hooe
Wheal Betsy
•
140
130
""
""
""
Garras, near Truro
Wheal Pool, Helston 50
Wheal Rose
60
"
The last mine, near Tavistock, produced in 1806 large quantities of
argentiferous galena, and about 1824 from 4,000 to 5,000 ounces of silver
were obtained annually from the lead and silver ores of that mine.
The Silver ore raised from Herland mine, in Gwinnear, at the beginning
of the present century produced above £8,000 sterling. In 1810 silver ores to
the value of £2,000 were raised from Dolcoath mine, near Camborne; and at
Wheal Brothers and Wheal Duchy, near Callington, in 1812, the value of
the silver obtained from ruby and grey silver ores and the black sulphide
was valued at £3,000. In recent years the following returns have been
made from the Callington mines:
Tons
cwts.
In 1877
142
15 (no value given of silver ore produced in Cornwall)
J
1878
94
9 valued at
1879
27
19
""
1880
14
8
""
S. d.
5,806 13 O
2,691 17 I
621 18 II
1881
5 18
358 7 0
The following table shows the quantities of lead ore raised in each year
since 1870, and gives the quantities of lead returned by the smelter, and
of silver separated, with some other particulars of especial interest, the result
of extensive inquiries, and constructed with much care to the end of 1880.
Silver
in a Ton
of Lead.
Lead
Ore.
Lead.
Silver.
Ore to make
100 Tons of
Lead.
Lead in
100 Tons
of Ore.
Year.
Tons.
Tons.
Ounces.
Tons.
Tons.
Ounces.
1870 98,176
73,420
784,562
133.718
74.783
10.687
1871 93,965 69,007
761,490
136.108
73°470
11.030
1872 81,564 60,420
628,920
135.001
74.076
10'402
1873
73,500
1874 76,801
54,283
531,077
135.521
73·784
9.792
58,777
509,277
129.610
77.154
8.672
1875 77,746 57,433
487,358
135.363
73.875
8.485
1876 79,096 58,667
483,422
135.058
73.053
8.253
1877
80,850 61,403
497,375
131.885
75.823
8.100
1878 77,350
58,023
397,471
133.316
75'010
6.850
1879 66,878
41,635
333,674
129.519
77.210
6.462
1880
72,245
56,949
295,518
126.876
78.527
5.189
1881 64,702 48,587
308,398
1882
65,001
59,328
372,446*
From this it will be seen that the produce of the lead mines has not only
regularly decreased, but that the amount of silver found in each ton of lead
has become less from 1871, with a steadiness which appears to point to
some special cause, which we are not enabled to explain. It may possibly
be that the silver has a tendency to decrease with the increasing depth, but
this is not by any means certain.
It is interesting to give the produce of lead ore and the yields of silver
from the most interesting and important Greenside mine, near Penrith.
1872 1,516 tons, yielding 17,000 ounces of silver. 1877 1,600 tons, yielding 15,726 ounces of silver.
1878 1,581
1879 1,527
1873 1,369
16,000
"
1874 1,276 ""
13,063
1875 1,558
""
15,809
1876 1,758
"}
7,914
""
""
99
14,075
>>
""
""
15,515
""
1880 1,527
13,801
",
1881 1,236
11,954
""
""
*Return of H.M. Inspectors of Mines.
CHAP. I.]
SILVER OBTAINED FROM LEAD ORE.
837
The ore obtained in this mine during the last ten years has been found
between two dead tracts on the north and south, running near a quartz felsite
dyke.
In the Appendix will be found reliable tables giving the production for
many years of the lead mines of Cornwall, Durham, and Northumberland,
of Cardiganshire, the Isle of Man, Scotland and Ireland, and of the lead ore
received by the Commissioners of Greenwich Hospital.
In 1851 the author published, in the "Mineral Statistics," the following
table, showing the production of silver, in the compiling of which he was
assisted by the late Mr. John Taylor:-
District producing Lead Ores.
Average
Quantities of
Pig Lead in each
per Annum.
Ounce of
Silver in each
Ton of Lead,
Ounces of
Silver from each
District.
Mean Average
Value of
Silver.
Tons.
£
Cornwall
Devonshire
Cumberland
7,304
25
255,640
63,910
1,026
40
41,040
10,260
5,702
9
51,318
12,829
Durham, Northumberland, and West-
moreland
13,233
12
158,796
36,699
Derbyshire.
4,250
None
Shropshire.
2,769
""
Yorkshire
•
5,223
I
""
Cardiganshire, Carnarvonshire, and
Carmarthenshire
3,492
15
52,380
13,095
Flintshire and Denbighshire
8,122
Montgomeryshire and Merionethshire .
679
76
56,854
14,213
4,074
1,018
Ireland
1,380
IO
13,800
3,450
Scotland
822
8
6,576
1,644
Isle of Man
1,699
20
33,980
8,495
Totals
55,7ΟΙ
674,458
168,614
The following table exhibits in detail the more important causes which
have led to the great depression prevailing for the last few years in the
lead trade of this country. It will be seen that in the last five years the lead
ore produced from British mines has fallen off to the extent of 15,298 tons,
and that the quantity of lead imported has for several years shown a con-
siderable increase :-
TABLE OF LEAD ORES, LEAD AND SILVER PRODUCED FROM THEM IN TEN YEARS TO 1881 IN
THE UNITED KINGDOM, THE IMPORTS AND EXPORTS, WITH MEAN PRICES.
Lead Ore.
Lead.
Silver.
Imports of
Lead.
Exports of
Lead.
Prices of
Lead Ore.
Mean Prices
of English Pig.
Year.
Tons.
Tons.
Ounces.
Tons.
Tons.
1872 81,564
60,420
628,920
69,841
44,330
£ s.
13 13
d.
1874 76,201
1873 73,500
54,235
531,077
62,563
32,010
58,777
509,277
61,987
36,353
15 8
14 13
906
£ S. d.
20 O O
23
6 O
22 2
1875 77,746
57,435
487,358
79,825
35,398
15 9 3
22 9 O
1876 79,096
58,667
483,422
80,649
35,921
15 8
O
21 13
O
1877 80,650
61,403
497,375
94,486
42,467
13 19 0
20 II
O
1878
77,350
58,020
397,471
100,141
34,385
IO II 6
16 14
O
1879
66,878
51,635
333,674
102,089
1880
72,245
59,949
295,518
95,049
36,776
33,551
IO 6 O
14 16
O
1881
64,702
48,587
308,398
93,400
43,109
II 6 O
10 3 0
16 17
O
14 19
O
* Those three counties do not receive from the smelters anything for silver contained in the ore. It
is not, therefore, returned. As a rule, the Shropshire ores may really be said to be non-argentiſerous.
Derbyshire lead contains only from I oz. to 2 ozs., and Yorkshire varies considerably from 23 ozs. to
5 ozs. All the silver is, however, separated in the processes of refining lead for the white-lead manufac-
turer. The mean average annual production of lead from the mines of the United Kingdom, from the
earliest period to the present time, may be estimated at 3,000 tons per annum, which will give 7,149,000
tons as the total quantity raised. The silver may be estimated to average five ounces to the ton of lead,
which will give 35,754,000 ounces.
3 H 2
838
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Hoping to convey a more exact impression of the variation in the pro-
duction of lead ore and lead, several tables are given in the Appendix,
from which the following respective facts have been drawn :-
1. The Production from the Lead Mines of Cornwall, showing that in 1845
10,110 tons of lead ore and 6,063 tons of lead were produced, which gradually
declined, until in 1881 764 tons 17 cwts. of lead ore and 408 tons 8 cwts. of lead
only were obtained.
2. An Account of the Production of the Lead Mines of Durham and
Northumberland. From this we see that in 1845 17,046 tons of lead ore were
raised, that in 1866 22,774 tons were obtained, which fell back to 14,186 tons
10 cwts. in 1879, which rose to 18,254 tons 19 cwts. in 1880, but fell again to
17,467 tons 2 cwts. in 1881.
3. The Production of the Cardiganshire Lead Mines.-From these impor-
tant mines-the working of which dates from the Roman occupation—in
1845 5,726 tons of lead ore, giving 3,716 tons of lead, were produced.
These in 1862 gave 8,299 tons 11 cwts. of lead ore, yielding 5,443 tons of
lead, from which time the production gradually declined, until in 1881 it
had fallen to 4,598 tons of ore, equal to 3,381 tons of lead.
4. The Production of the Lead Mines of the Isle of Man was in 1845
2,259 tons of lead ore, which gradually increased to 1871, when these mines
produced 4,645 tons, which gave 3,334 tons of metallic lead; then each
year—with one exception—the production steadily increased, until in 1881
these mines gave 5,675 tons of lead ore, yielding 4,183 tons 12 cwts. of lead,
with 84,865 ounces of silver.
5. The Production of the Lead Mines of Scotland was in 1845 1,173
tons of lead ore. This steadily and regularly increased, until in 1881 3,806
tons 17 cwts. were produced.
6. The Production of the Lead Mines of Ireland shows that in 1845 1,944
tons of lead ore were obtained, which gave 855 tons of lead. This was
increased to 4,493 tons of lead ore and 3,222 tons of metallic lead in 1852,
which at once fell back, producing for several years with much regularity
rather more than 2,000 tons of lead ore, until in 1865 the quantity declined,
and this continued until 1881, when the Irish lead mines produced only
848 tons 16 cwts. of lead ore, giving but 636 tons of lead.
7. The Production from the East and West Allendale Mines and the
Weardale Mines was in 1845 12,200 tons of lead ore and 8,130 tons of
lead. The returns of silver were not obtained until 1853, when 11,916 tons
of lead ore, giving 9,904 tons of metallic lead and 50,700 ounces of silver,
were returned. From that period until 1868 there was but little variation,
the production being then 12,360 tons of lead ore. A steady decline set
in, until in 1879 only 1,624 tons of lead ore were produced, which rose in
1880 to 3,910 tons, and in 1881 to 3,273 tons, giving 2,454 tons of lead and
16,968 ounces of silver. At this time these important mines were suspended,
but operations have been recently commenced anew.
8. The Total Production of Lead Ore, Lead, and Silver from 1848 to 1871
inclusive, shows a constant increase, from 78,944 tons of lead ore in 1848 to
93,965 tons in 1871, giving 69,037 tons of metallic lead and 761,490 ounces of
silver. From this period the production gradually declined.
CHAP. I.]
CALAMINE EARTH AND BLENDE.
839
9. The other tables are of considerable interest, the first giving the
quantity of lead ore paying duty to the Greenwich Hospital, from 1768 to
1845. The second giving the prices of lead at the Grassington Lead
Smelting Works belonging to his Grace the Duke of Devonshire, from 1780
to 1843, which is a curious illustration of the variations in the price of a
natural product. The last records the prices of English tin per fodder from
the year 1783 to 1800.
A table has been given which shows that in 1858 the United Kingdom
produced 11,556 tons of zinc ore, and that to 1881 there has been a regular
increase in the production, until it reached 35,527 tons, falling back in 1882
to 32,538 tons; the prices varying but little; the lowest price being in 1861,
when zinc ore was £2 a ton and metallic zinc 2. In 1872, the price of zinc
ore reached £4 8s., and in the next year metallic zinc was £26 15s.-the
highest price.
A table is also given showing the imports and exports of zinc, and
much valuable information, from 1823 to 1858.
ZINC.-That Zinc was used at a very early period in the metallurgical
arts is certain, but the metallic character of its ores was not understood,
even so late as 1741. Calamine ore was used, and it was regarded as a semi-
metal. The oxides and carbonates of zinc were regarded as earths, in the
sense in which that term was used by the alchemists. As Calamine Earth it
was employed in the production of alloys with copper, by the Tyrians, and
probably by the Assyrians.
Dr. Watson* says: "The two principal ores of zinc are calamine and blende.
The Arabic word climia, or, as it is pronounced by some, calimia, denotes
the same substance which we call Lapis calaminaris, calamine or calamy, and
hence Salmasius † is of opinion that they judge very preposterously who
would derive calamine from calaem, an Indian word.
'The other ore of zinc is called by the Germans blende, from its blinding
or misleading appearance, it looking like an ore of lead, but yielding (as
was formerly thought) no metallic substance of any kind. They have in
Staffordshire a sort of iron which they call blende-metal, of which they make
nails, hammers, &c.§ Calamine is found in Somersetshire, Derbyshire, and
Flintshire, and other parts of England. Before the reign of Elizabeth,
Sir John Pettus says, this mineral was held in very little estimation in
Great Britain, and even at so late a period as towards the end of the last
century, it was commonly carried out of the kingdom as ballast by the
ships which traded to foreign parts, especially to Holland."
"Great quantities of calamine have of late years," says Dr. Watson,
writing in 1786, "been dug in Derbyshire, on a spot called Bonsall Moor, in
the neighbourhood of Matlock." "A bed of iron-stone, about four feet in
thickness, lies over the calamine, and the calamine is much mixed, not only
with this iron-stone, but with cawk, lead ore, and Limestone."
* "Chemical Essays," vol. iv. 1786.
+ "Cadmia Arabicus dicitur climia, quod quidam pronuntiarunt calimia, unde Græcis recentioribus
Xeλquia interdum scribitur unde nostris Gallis calamina et lapis calaminaris" (Salmasius, De Homony, Hy.
Sat. ccxxii.).
‡ "Germanis appellatur blende a blenden quia, cum falso speciem minera Saturninæ præ se sert,
exinde oculos fascinet, vel iis præ se sert" (Pott, " De Pseudo-Galena," p. 106).
§ Plott's "Staffordshire."
"Essay on Metals" and "Philosophical Transactions" for 1694.
840
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
"The calamine annually (1786) raised in Derbyshire amounted to about
1,500 tons a year. Sixty years previously they did not raise 40 tons a year.
The Derbyshire calamine did not bear so good a price as that which is
gotten about Mendip, in Somersetshire, the former being sold for about 40s.,
and the latter about 65s. or 70s. a ton before dressing. When thoroughly
dressed the Derbyshire calamine may be bought for about six guineas, and
the other for £8 a ton. There are many sorts of blende, or black-jack,
which differ from each other not only in their external appearance, but in
their internal constitution." Dr. Watson is not quite right in this. The
zinc ore (blende, sulphide of zinc) varies in appearance from its sometimes
containing silver, copper, or iron; but these are merely mixtures.
Dr. Watson says that Margraf, in 1746, by distillation, ascertained the
quantity of zinc in different sorts of calamine to be as follows:-
Calamine from near Cracow
Parts. Parts.
16 gave 2 Zinc.
دو
""
""
""
England
Holywell (Flint)
Hungary.
•
Breslaw
•
16
99
3
16
99
7
""
16
2
""
"
16
42
""
+
""
Plott, in 1741, says: "This semi-metal, which at present is called zinc,
was not known so much as by name to the ancient Greeks and Arabians.
The name which it bears at present first occurs in Theophrastus Paracelsus,
but no one as yet has been able to discover the origin of this appellation.
A. G. Agricola* calls it contrefeyn; Boyle, speltrum; by others it is deno-
minated spianter and Indian tin. Albertus Magnus,† who died in 1280, calls
calamine golden marcasite, and asserts that it approaches to a metallic nature.
Pott, in his book on zinc, speaks of the ores of zinc being yellow and
red. Jungius ‡ says that in 1647 an ore of this kind, under the name of
tutenag, is still brought from India, from which we may infer that for some
time we had been indebted to the East for that metal. Matthiolus, Agricola,
Caneparius, and others esteemed calamine to be a mineral in which there
was no metallic substance.§ G. E. van Lohneiss, in 1617, says that zinc had
for a long time been collected by fusion at Goslar. Erasmus Ebner appears
to have been the first, about 1550, who first distilled the cadmia of Goslar.
In 1721 Henkel tells us zinc may be obtained from Lapis calaminaris by
means of phlogiston. In 1742 Anton van Swab extracted this metal from
its ores by distillation, and in 1746 Margraf published a method of his
own for effecting this.
A manufactory was established at Bristol, where zinc was obtained by
distillation per discension. Dr. I. Lawson is said || to have been "the first person
who showed that calamine contained zinc. We have now on foot at home, a
work established by the discoverer of this ore (?) which will probably make
it very unnecessary to bring any zinc into England," Dr. Plott says, "To
all this I shall only add one testimony more, from which it may appear that
the English knew how to attract zinc from calamine before Mr. Van Swab
taught the Swedes the method of doing it, though this gentleman, unless I
have been misinformed, instructed the late Mr. Champion, of Bristol, either
*De re Metallica."
"De Mineralibus.'
†
"In Libro Mineralium.”
§ Caneparius, "De Atram," pp. 12, 21.
Supplement to "Chambers's Dictionary," published in 1753.
CHAP. I.]
THE MANUFACTURE. OF BRASS.
841
in the use of black-jack for the same purpose as calamine, or taught him
some improvements on the methods of obtaining zinc from its ores. The
testimony occurs in a dissertation of Henkel's on zinc, published in 1737.
He is there speaking of the great hopes which some persons had entertained
of the possibility of obtaining zinc from calamine; hopes, he says, which had
been realised in England: 'ce qu'un Anglois arrivé depuis peu de Bristol, dû
avoir vu réussir dans son pays.' , * The manufactory of zinc was estab-
lished in Bristol in the year 1743, when Mr. Champion obtained a patent for
making it. About 200 tons were made annually at these smelting works.
James Emerson began to make zinc at Henham, near Bristol, in 1777. The
process of distillation was adopted, the metal being "condensed in small
particles in water, and being re-melted, was formed into ingots and sent to
Birmingham under the name of 'spelter'" (Watson).†
Calamine Earth had long been used in the manufacture of brass.
Queen Elizabeth in 1565 granted to her Assay Master, William Humphry,
a German, "a workman of great cunning and experience in the proper
use of calamine, for the mixt metal called latten, or brass," a patent for
the manufacture of this. In 1568 the Society of Mineral and Battery
Works were actively making latten, and we find in the time of Henry VI.
that his chaplain, John Bottwright, was made comptroller of all the
mines, including latten and lead, within the counties of Devon and Corn-
wall. In 1639 a proclamation was issued prohibiting the importation of
brass wire; and in 1650, Demetrius, a German, founded a brass work in
Surrey, at the expense of £6,000. Eight thousand men are said to have
been employed in the brass manufactories near London and in Notting-
ham. Yet Sir John Pettus in 1670 § observes that these brass works were
then decayed, and the art of making brass almost gone. In 1708 there
were brass manufacturers in England who presented a memorial to the
House of Commons, soliciting the protection of Parliament. They stated
"that England by reason of the inexhaustible plenty of calamine might become
the staple of brass manufactory for itself and foreign parts," and they argue
that the continuing the brass works in England would occasion plenty of
rough copper to be brought in. This would appear to show that but little
copper was mined in this country at that period. Yet in 1720 we find
Mr. W. Wood || stating that "this nation could supply itself with copper and
brass of its own produce sufficient for all occasions if such duties were laid on
Foreign copper and brass as would discourage their importation.” In 1783 a
bill was passed in the House of Commons repealing certain statutes ¶ and pro-
hibiting "the exportation of brass, copper, latten, bell-metal, pan-metal,
gun-metal," &c. In 1721, when various goods or manufactures of Great
Britain were allowed by Act of Parliament to be exported free of duty
* This observation was first published in the fourth vol. of the "Acta Physico-Medica," Acad. Nat.
Cur., 1737, but I have made the quotation from the edition of Henkel's works published at Paris, 1768,
vol. ii. p. 494.
There is another substance which is denominated spelter, or spelter solder, by the braziers. It is
composed of two parts of zinc and one of brass" (Watson).
c. 37.
"Essay on Metal" (Brass), quoted by Dr. Watson.
Fodinæ Regales."
"State of the Copper and Brass Trade.'
¶ Those of 28 Edward III. c. 5; 21 Henry VIII. c. 10; 33 Henry VIII. c. 7; 2 & 3 Edward VI.
842
FUTURE PROSPECTS OF BRITISH MINING.
[BOOK IV.
-lapis calaminara-lead and several other articles are enumerated in the
Act on which the duty was to be continued (Watson).
Diego Ufano, in his "Artillery," published in 1614, gives the following
statement of the metallic mixture used for the casting of cannon in Europe :-
Copper
Tin.
Brass
•
160
ΙΟ
8
•
100
20.
5 ·
•
•
100
8
5
•
100 parts.
8
""
Bell-metal was made of one part of tin melted with four parts of copper,
and zinc was added for small bells. A method for applying zinc upon
hammered iron saucepans was introduced at Rouen about 1786. There was
considerable prejudice against its use. A French physician, M. de la
Planche, published a statement to the effect that he took the salts of zinc
formed by vegetable acids in much stronger dose than the aliments prepared
in copper vessels lined with zinc could have contained them, and he felt no
dangerous effects. *
We find in Beckmann's "History of Inventions" the following note,
appended by the recent editors to the article "Zinc":-
"Most of the zinc works in this country are situated in the neighbourhood
of Birmingham and Bristol; a few furnaces also exist in the neighbourhood
of Sheffield, among the coal pits surrounding that town. There is also one
at Maestag, in Glamorganshire. The ores worked at Bristol and Birming-
ham are principally obtained from the Mendip Hills and Flintshire, those at
Sheffield from Alston Moor." †
The production of zinc in the United Kingdom was as follows in 1881,
when the returns made to the Mining Record Office were discontinued :-
No. of
Mines.
44
Cornwall
Shropshire
Derbyshire
Countries, &c.
ENGLAND.
Zinc Orc.
Metallic Zinc.
Tons cwts. qrs.
7,792 17 3
196 17
Tons cwts. qrs.
о
3,507 15
107 5
SH
5
Cumberland
40 O
1,771
16 10
I
I
Yorkshire.
35 5 0
284 19
15 17 0
WALES.
13
I
3A54∞ 2
I
2
Cardiganshire.
Montgomeryshire
Denbighshire
Flintshire
Carnarvonshire
Anglesea .
ISLE OF MAN
SCOTLAND
•
3,453 3
1,414 O
HO
I
50
5,602 5
4,233 8
1,863 5
•
792 8
2,305 12
2
291 10
I
632 0
7,567 10 O
323 0 0
3,480 O O
61 10 о
Total.
· 35,527 7 3
14,947 5 0
1,544 19 I
610 O
2,531 15
* Fourcroy's "Chemistry," vol. i.
+ "A History of Inventions, Discoveries, and Origins." By John Beckmann. Translated by William
Johnston. Fourth edition. Revised by William Francis, Ph.D., and J. W. Griffith, M.D. (Henry G.
Bohn. 1846.) The zinc smelting works in 1881 were-
The Bagilt Zinc Company.
Vivian and Sons, Swansea.
Kenrick and Sons, Ruabon.
Zinc Works Company, Warrington.
Dillwyn & Co., Swansea.
Joseph Thompson, Carlisle.
Richardson & Co., Swansea.
Villiers Company, Morriston, Swansea.
Swan & Co., Mary-hill, Glasgow.
Swansea Vale Company, Swansea.
CHAP. I.]
PRODUCTION OF ZINC ORE.
843
The Inspectors' returns for 1882 give zinc ore 32,538 tons, and metallic
zinc 16,130 tons. These all go to prove that until recently the production
of the ores of zinc-either the sulphide of zinc (black-jack), calamine (carbonate
of zinc), or Smithsonite (silicious oxide of zinc)—has been small.
THE PRODUCTION OF ZINC ORE FROM THE MINES OF THE
UNITED KINGDOM SINCE 1858.
Blende.
Zinc.
Blende.
Zinc.
Year.
Tons cwts.
Tons.
Year.
Tons cwts.
Tons.
1858
11,556 2
3,466
1871
17,736 10
4,966
1859
13,039 I
3,697
1872
18,542 12
5,191
1860
15,552 14
4,357
1873
15,969 I
4,47I
1861
15,770 3
4,415
1874
16,829 16
4,470
1862
7,497 12
2,151
1875
23,978 8
6,713
1863
13,699 2
3,835
1876
23,613 8
6,641
1864
15,047 6
4,040
1877
24,405 16
6,833
1865
17,842 15
4,460
1878
25,438 2
6,309
1866
12,769 20
3,192
1879
22,199 19
5,554
1867
13,489 8
3,750
1880
27,547 15
7,162
1868
12,781 13
3,713
1881
35,527 7
14,947
1869
15,532 20
4,500
1882
32,538 14
16,130
1870
13,563 10
3,936
The quantities of zinc ores produced in the several metalliferous districts.
of the United Kingdom in each of the five years ending in 1882 are shown
in the following table :-
Average
No. of
Mines.
Counties.
1878.
1879.
1880.
1881.
1882.*
Tons.
Tons.
Tons.
Tons.
Tons.
4,482
3,901
4,439
7,792
4,607
598
439
444
196
913
5
35
109
4
79
57
40
1,566
1,524
991
1,771
1,716
I
131
505
525
2,629
3,453
3,542
2,217
1,927
1,581
1,414
1,528
2,984
3,230
4,016
5,602
6,031
2,666
2,898
3,970
4,233
4,410
•
504
667
728
792
617
2,305+
1,240†
•
9,569
7,427
8,409
7,567
7,757
235
76
109
323
59
100
184
40
II
5
Cornwall
Shropshire
•
I
Yorkshire
I
Derbyshire
7
Cumberland
I
8
5
3
4
Durham
Cardiganshire
Montgomeryshire.
Denbighshire
Flintshire
•
4
2
Carnarvonshire
Anglesea
5
Isle of Man .
I
Scotland
•
I
Ireland
The quantity of calamine removed from the native deposits named cannot
even be guessed at. It was regarded as a peculiar earth, not unlike alumina
or magnesia, and its use was chiefly for the production of brass, although the
* Inspectors' returns.
†These returns consist of "bluestone," a compound ore, which, from analyses of 800 tons of this
mineral by Mr. E. A. Parnell, of Swansea, gave the following results :—
Zinc
Lead
Iron
Sulphur
Arsenic
Copper
Silver.
Gold .
Alumina
Carbon
Silica.
Loss
•
•
•
•
27.45
ΙΟΙΙ
•
7.91
23.63
0.04
0.95
0.0263
Traces.
2.98
I'00
24.99
0.73
99.8963
844
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
brass-makers do not appear to have been aware of the fact that they were
dealing with a metallic compound. At one time, without doubt, considerable
quantities of calamine were obtained. These were generally superficial
deposits, and they have been for the most part worked out.
As the sulphide of zinc was generally found associated with copper or
lead ores, and separated in the process of dressing, we have no satisfactory
statement of the period at which the miners began to save the zinc ore
(black-jack). That "Black Jack rides a good horse" is an old proverb
arising from the fact that the dark zinc ore is frequently found above the
ores of copper or lead. It may be safe to assume that zinc ore has been
saved when found for at least one hundred years. The rapid increase in the
production of zinc ore since 1858, and especially since 1874, is due to the
numerous new applications which have been found for the metal zinc.
We
shall probably not be far wrong when we state our conviction that since
the ore of zinc has been one of the products of mining industry, there
has been raised and utilised not less than 2,500,000 tons, yielding to the zinc
smelter about 600,000 tons of metallic zinc.
Our exports of British zinc, and our imports of crude zinc have been of
late years as follows:
Year.
1876
1877
1878
1879
1880
1881
British Zinc Exported.
Tons.
5,673
5,788
6,665
5,673
8,023
7,743
Import of Zinc.
Crude.
Tons.
Manufactured.
Tons.
29,466
14,719
35,094
16,102
32,750
16,207
34,180
15,474
33,409
16,648
46,198
19,302
From this it will be seen that the zinc obtained in these islands has not
been equal to supply the demands of our manufacturers.
IRON ORE.-There exists considerable difficulty in determining the
quantity of iron ore which has been exhausted from the collieries and mines
of this country. The chapter on the production of iron, and the historical
sketch of the iron manufactures, includes nearly all the obtainable infor-
mation. For 1881 the Inspectors' returns give of—
Ironstone from the Coal Measures
Iron ore from metal mines
""
""
""
Lincolnshire*
Northamptonshire*
sundry districts*
Total
•
Tons.
II,505,447
3,596,747
1,021,506
1,270,544
500,000
17,894,144
For many years we have been exhausting our iron ore deposits at this
enormous rate. The argillaceous ores of the Coal Measures are very nearly
finished, and considerable tracts of country which have produced iron ores
in considerable quantity now yield them very sparingly. We produce
annually 8,144,449 tons of pig iron. To obtain this we are obliged to
import from Foreign sources 2,450,000 tons of iron ore; and from pyrites
imported chiefly from Spain, we separate 408,000 of "purple ore," which is
separated in the process for obtaining the copper and silver they contain.
* The Inspectors of Mines could only obtain returns from mine-working. The ores procured from
open workings or quarries were not, under the Mines Regulation Acts, to be returned to the Inspector.
CHAP. I.]
MISCELLANEOUS MINERALS.
845
Our pig-iron manufactures consume considerably more than 20,000,000 tons
of iron ore annually.
MISCELLANEOUS MINERALS.-The following table will convey a
sufficiently correct idea of the less valuable of the metalliferous ores and of
some of the more important earthy minerals raised annually in these islands,
according to the latest returns obtainable :-
1. Pyrites (Sulphide of Iron)
2.
Do. (Copperas lumps)
3. Gold (Ireland), I cwt. I qr. 27 lbs.
4.
Blue Stone
5. Silver Ore
6.
Nickel and Cobalt
7.
Wolfram
8. Fluor-spar, &c.
9. Ochre and Umber
10. Manganese
II.
Arsenic
I2.
Salt
13. Barytes
•
Produce in 1881.
Tons.
•
1,246
43,616
5,370
•
Produce in 1882.*
Tons
..18,550
cwts.
6,847
•
2,305
6
•
7
63
38
о
54
57
372
144
O
7,966
5,101
2,884
•
1,548
6,156
2,298,220
5,972
2,185,002
22,294
No return
14. Coprolites and Phosphatic Nodules.
15. Phosphate of Lime.
16. Gypsum.
21,313
31,500
60
79,498
•
· 50
86,086
O
It is important, before we enter on the consideration of the future pros-
pects of mining in this country, that a clear conception should be arrived at
of the real value for the more recent years of the products of all our mines. A
table has, therefore, been constructed which gives the amount of all the
minerals of commercial, or industrial value, which have been raised in the
United Kingdom during the five years ending with December, 1881. It has
been felt necessary to include the coal, the iron ores of the Coal Measures,
the salt, and clays, which form no part of the subject comprehended in this
volume. The history of British mining has been traced, often imperfectly-
but always with every desire to arrive at correct conclusions-from the
period when the uncivilised Briton traded with the Phoenician sailors † until
the year 1881, when the value of the mineral productions of these islands
reached the enormous value of £90,860,487 sterling, as will be seen by the
following tables, compiled from returns made to the Mining Record Office.
* 1882 is from the Inspector's Report, published 1883. It does not contain, in some cases, the total
production.
+ While these sheets have been passing through the printers' hands, a small work on "Celtic Britain,"
by J. Rhys, M.A., Professor of Celtic in the University of Oxford, has come into the author's hands, in
which the following passages occur: "There is not a scrap of evidence, linguistic or other, of the presence
of Phoenicians in Britain at any time, and the supposed proof (in the writings of Festus Avienus, a somewhat
confused poet of the fourth century) that Himilco, in the flourishing times of Carthage, carried his voyage
of discovery so far as this country, is exceedingly unsatisfactory."
Thanet
Relying almost entirely on collections of coins, Professor Rhys writes: "A study of the early money
of Britain also throws some light on the paths of intercourse between it and the continent.
would seem to have been the island at high tide to which the tin of the west was brought in coracles by
the natives for sale to the merchants who came for it from Gaul. The coasting voyage seems to have taken
the former six days to make." The statement made by Diodorus is then given, and the Iktis is especially
noticed as follows: "But the island itself can hardly have been St. Michael's Mount, as has sometimes been
supposed, since that does not seem to have been an island at all in old times; nor was it the Isle of Wight,
for that was never accessible on foot. In all probability it was no other than Thanet, which must formerly
have corresponded completely to the description already cited."
The author feels it due to so eminent a Celtic scholar as Professor Rhys to state his opinion, directly
opposed as it is to his own views. In the early pages of this volume the authorities are given, which appear
to prove satisfactorily that the Phoenicians traded with, and ultimately settled in, Cornwall. Beyond this,
the evidences of tradition,-which were more striking half a century since. than they are now, the existence
of superstitions of evidently oriental origin,‡ the mining terms which unmistakably come from the East,
and the connection through all historic time, of the Jews with tin-mining, appear conclusively to determine
the question in favour of the views expressed in the Historical Sketch of this volume.
See "Popular Romances of the West of England." By Robert Hunt, F.R.S.
846
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
THE MINERAL PRODUCTIONS OF THE UNITED KINGDOM.
COAL.
IRON ORE
TIN ORE
15,045 14
530,737
COPPER ORE
1877.
MINERALS, &C.
Quantities.
Value.
Tons cwts.
£
1878.
1879.
1880.
Quantities.
Value.
Quantities.
Value.
Quantities.
Tons cwts.
£
Tons cwts.
£
Tons cwts.
Value.
£
1881.
Quantities.
Tons cwts.
Value.
134,610,763 047,113,767 132,607,866 0 46,412,753 134,008,228 0 46,902,879 146,818,622 o 62,395,414 154,184,300 o 65,528,327
16,692,802 0 6,746,668 | 15,726,370 I 5,609,507 14,379,735 0 4,962,434
14,142 6
572,763
12,893 3 697,444
65,528,327
|
18,026,049 16 6,585,806 17,446,065 6 6,201,068
14,665 O
586,608
13,737 II
673,142
73,141 O 262,270
56,094 O
201,434
51,032 0
177,328
52,118 0
190,667
52,556 I 190,057
LEAD ORE.
80,850 0 I,123,952
77,350 O
801,428
66,877 O
688,740
72,245 O
816,368
64,702 5
656,725
ZINC ORE
24,405 16
86,151
25,438 2
80,565
22,199 O
81,531
27,547 15 90,545
35,527 7
110,043
IRON PYRITES
43,948 10
28,225
29,867 15
19,099
20,275 O
11,835
31,708 2
23,004
43,616 14
30,033
ARSENIC
4,809 4
30,420
4,991 IO
26,900
5,492 IO
34,180
5.738 5
43,498
6,156 8
45,070
MANGANESE
3,038 14
7,958
1,536 4
3,120
816 8
1,515
2,839 I
5,601
2,884 o
6,441
BISMUTH
8
15
I
14
COBALT and NICKEL
27 4
242
98 18
616
116 II
883
49 3
297
63 14
310
GOLD ORE
18
2 0
25
I IO
18
SILVER ORE
142 15
927
94 9
5
27 19
621
14 8
2,961
5 19
358
URANIUM
2
II
8
44
5
41
WOLFRAM
15 O
150
ΙΟ O
ΙΟΟ
13 O
120
20
8
54 7
544
FLUOR-SPAR, &c.
OCHRE and UMBER
CLAYS (Fine and Fire)
SALT.
220 3
5,074 3
2,961,155 O
2,735,001 0
36
391 17
133
1,264 16
422
458 2
350
4,488
4,414 17
4,038
592,231
2,711,486 o 677,871
1,504,250
2,682,930 0 1,344,465
BARYTES
21,056 7
28,948
22,435 16 36,606
3,973 12
3,436
2,888,489 o
717,143
2,558,368 0 1,279,184
19,349 18
21,068
6,126 9
3,062,544 0 1,635,650
2,645,000 0 1,322,500
18,476 19 13,383
11,512
7,966 9
2,401,421 O
2,298,220 O
12,286
1,200,210
1,149,110
21,313 II
23,894
CALC-SPAR
2,351 2
COPROLITES, &c.
69,006 o
625
200,000
OIL SHALES
123,558 O
61,779778,029 o 512,200
525,950 O
262,975
275,500
349,500
GYPSUM
73,908 O
22,172
SUNDRIES
10,000
1877
1878
1879
:
TOTAL VALUES OF ORES RAISED.
£
s. d.
58,398,071 10
1880
56,246,495 10
1881
55,733,967 19 ΙΟ
£
S. d.
74,094,638 17 5
76,201,695 2 2
CHAP. I.]
TOTAL PRODUCTION OF MINERALS.
METALS.
1877.
1878.
METALS OBTAINED FROM THE ORES PRODUCED IN THE UNITED KINGDOM.
1880.
1879.
1881.
£
£
£
£
£
GOLD
143 ozs.
636
PIG IRON
TIN
9,500 ",
COPPER
4,486
6,600,664 tons 16,191,236
695,162
340,067
""
702 ozs. 2,848
6,154,992 tons 16,154,922
10, 106
663,080
9,532,,
447 ozs.
1,790
5,995,337 tons 14,988,342
689,163
IO OZS.
. 39
4½ ozs.
18
7,749,233 tons
19,373,082 8,144,449 tons 20,361,122
8,918,,
,813,767
8,615,
830,680
3,952,
271,042
3,462
""
222,507
3,662,,
253,277
3,875,
263,500
LEAD.
ZINC
SILVER FROM LEAD
SILVER FROM ORE
61,403
6,281
497,375 ozs.
""
1,262,600
58,020
""
972,491
51,635
""
756,489
56,949
""
953,895
48,587
""
728,805
"
136,612
6,309 ››
123,025
5,554 ",
95,806
7,162,,
123,524
14,947,, 252,608
113,950
397,471 ozs.
88,296
333,674 ozs.
70,905
295,518 ozs.
63,015
308,398 ozs.
67,140
4,069
""
927
27,648
6,223
""
3,000,,
620
1,765,
382
1,650
""
360
OTHER METALS-
Estimated Value.
1,750
1,125
1,000
17,500
TOTAL VALUE OF METALS OBTAINED.
Metals.
£
Coal.
£
Earthy Minerals, &c.
Total.
£
1877
18,742,960
47,113,767
2,424,679
68,281,406
1878
18,283,124
46,412,753
2,643,404
67,339,281
1879
16,835,622
46,902,879
2,333,769
66,072,271
1880
21,582,501
62,395,414
3,539,635
87,517,550
1881
22,514,508
65,528,327
2,817,652
90,860,487
847
848
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
It must not be forgotten, that mineral treasures have been continuously
excavated from our rocks and the alluvial deposits for more than 2,000
years, consequently a considerable exhaustion of "the corpus" must have
been the result.
The great Linnæus wrote: "Stones grow. Plants grow and live. Animals
live and move." Let it be distinctly understood, in opposition to this great
authority, that stones do not grow. They may increase in size by the accretion
and aggregation of similar particles together, but growth is the increase of
size by the addition of matter under circumstances which involve in some
form, or other, chemical change. There has not been, therefore, any growth
of any mineral during the 2,000 years which have elapsed since man
brought his efforts to bear on the search for mineral treasures in the super-
ficial crusts of our planet.
In the caverns of the Earth-in the fissures of the rocks-through which
water holding mineral matter in solution has been for ages percolating,
crystallization has been active, and beds of mineral matter have been
formed. This has been effected in many cases by precipitation from
water, of matters held in mechanical suspension, and in other cases by the
crystallization of salts, held in solution under the influence of oxidising
agents.
We certainly have occasional evidences of the decomposition of a mineral
lode in one place, leading to the formation of soluble salts, which have been
carried by the circulating fluids to another place of repose, and Nature has
produced, by the influences of silently operating forces, geometric forms
of exquisite work and beauty.
We find some varieties of copper ore which are evidently of recent origin,
and instances have occurred in both Cornwall and Wales in so-called
exhausted lead mines, where the abandoned levels have been filled, or at all
events, the walls lined with the phosphate, arseniate, and other ores
of lead.
While admitting the fact that minerals of comparatively recent origin
may be forming at the present time, we must not fail to impress upon our
readers that man has removed vast masses of metalliferous ores with
rapidity, while the reproduction by Nature of a few rare minerals has
proceeded with infinite slowness.
Wallace* draws attention to the removal of lead ore from the veins in
Alston Moor. "Undoubtedly," he says, "many of the portions of veins
contained at some former geological period much richer deposits of lead ore
than when first laid open by mining operations." Other evidences might be
brought forward to show that new deposits have been formed before man
began to penetrate the surface, and since, with avaricious zeal, he has
laboured to find the buried wealth. But these changes would never repro-
duce in the fissures of the rocks one-millionth part of the metalliferous ores
which man has removed.
PYRITES.—The production of pyrites (sulphur ores, mundic, arsenical
ores) from the mines and collieries of the United Kingdom has been com-
paratively unimportant. It may, however, be expected-now that the value
* "The Laws which Regulate the Deposition of Lead Ore in Veins." By William Wallace.
CHAP. I.]
PRODUCTION OF MANGANESE.
849
of Pyritic Ores is becoming better understood-that more attention will be
paid to the preservation of the minerals of this character.
In 1878
29,867 tons were produced of the value of .
1879
20,275
""
"
1880
31,708
""
""
""
1881
43,016
""
""
1882
25,403
,,
""
""
6,847
""
""
""
£
s. d.
19,099 5 10
11,835 13 3
23,004 9 5
30,033
14,459 O
3,594 O
The imports from 1877 to 1881 of pyrites of iron and copper will show-
Norway. Portugal. Spain.
Other
Ports.
Total.
Total
Value.
Year.
Tons.
Tons.
Tons.
Tons.
Tons.
£
1877 8,564
149,562
498,977
22,209
679,312
1,643,614
1878 5,773
136,705
419,561
12,318
579,261
1,336,047
1879 8,485
82,529
374,505
15,873
481,392
1,050,545
1880 10,952
166,519
463,199
8,684
658,047 1,522,724
1881
542,378 1,202,281
The real value of these sulphur ores will be apparent when we state that
in addition to the sulphur and iron, the ores imported in 1881, gave of—
Fine Copper
Silver
Gold
1881.
14,000 tons
258,463 ounces
1,490
""
1882.
15,300 tons.
400,000 ounces.
1,500
""
The copper was obtained from "burnt ore," that is, from the residuum after
the sulphur had been separated by calcination. The principal portion of
the silver and the whole of the gold was got from copper liquors by Mr.
Claudet's patent process. A small portion of the silver was separated from
copper precipitate by the manufacturers of sulphate of copper.
MANGANESE.-The principal manganese ores obtained in these
islands are-
1. Pyrolutite-Cornwall, Warwickshire
2. Manganite-Cornwall, Devonshire,
Warwickshire, Scotland, Ireland
Devonshire,
Somersetshire,
3. Psilomelane — Cornwall, Devonshire, Cumberland,
Scotland, Ireland
4. Wad-Devonshire, Derbyshire
The quantities obtained have been—
Oxygen.
31.7
Manganese.
63°3
Oxide of Manganese.
89.90
69.80 and 81.8
63.60
""
66.5
Quantities.
Value.
Imports.
Value.
Year.
Tons cwts.
£
S.
d.
Tons.
1877
3.038 14
7,958 I
6
13,176
67,878
1878
1,586 4
3,120 17 2
9,820
40,225
1879
816 8
1,515 10 O
12,172
45,873
1880
2,839 I
5,601 7
16,085
67,070
18,748
71,140
1882
1,548 5
3,907
29,760
102,267
1881 2,884 I 6,441 5
The recent discovery of very extensive beds of manganese in America
must tend to the reduction in value of the small production of this country.
In concluding this section of our inquiry, it may not be out of place to
draw attention to the fact that the deepest tin mine in England is still the
richest. This appears to show that probably metalliferous veins, especially
* Inspectors' returns including pyrites (brasses) from the Coal Measures and copperas lumps.
850
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
those containing tin, extend to a far greater depth than has yet been
explored. At the present time, 1883, the tin lode at Dolcoath at the depth
of 420 fathoms is seven fathoms wide, yielding a very high percentage of
black tin.
The following account of this remarkable mine was given by the
manager, Captain Josiah Thomas, on the visit of the Polytechnic Society in
1882:
"Dolcoath was worked for several years in the last century, and was
suspended in 1787. The present company recommenced working her in 1799.
"The sett is about three-quarters of a mile in length, on a line with the
lodes, which have a direction about east and west. About 70 miles of level
have been driven on the various lodes. The mine is now above 400 fathoms
deep (half a mile). The total money paid out of the adventurers' pockets
from the commencement of the present company was £45,000. They have
raised three and a half million pounds' worth of copper, two million pounds'
worth of tin, and thirty thousand pounds' worth of arsenic, silver, &c., the
total produce being worth over £5,500,000 sterling. The dividends during
the present workings of the mine amounted to upwards of £560,000, of which
more than £266,000 had been divided during the past fourteen years. They
have thirteen steam-engines at work, and one thousand two hundred people
employed. They were now raising one hundred and fifty tons of stuff a
month. They are not raising copper. The profits are now between £30,000
and £40,000 a year, or nearly a profit per annum, equal to the whole outlay
ever made on the mine."
There is every reason for supposing that the conditions found at Dolcoath
will prevail over the district shown in the map of the mineral veins and
cross courses, in the district of Carn Brea and Illogan, including Camborne
and Redruth. It would therefore appear to be well deserving of careful con-
sideration whether it might not be found profitable to penetrate still deeper
into the Earth in some of the stanniferous districts of Cornwall and Devon-
shire. The additional cost of sinking the mines might be met by a rigid
economy, and by the introduction of machinery, for boring, for ventilating
the mines, and for lowering and raising the miners.
There have been at work in this country during the last ten years the
following number of tin mines. The variations in produce relatively to the
number of mines worked demand especial attention :-
1872
1873
•
1874
1875
1876
Tin Ore.
Tin Ore.
162-producing 12,299 tons.
1877
98-producing
•
215
""
14,884
1878
90
""
230
183
135
>>
14,039
13,995
13,688
1879
86
1880
""
91
""
1881
95
14,091 tons.
15,045
14,665
13,737
12,900 ""
""
It is desirable to bear in mind that little or no tin can be expected to be
obtained in the future from alluvial deposits. Nearly all the veins pro-
ducing tin, at comparatively shallow depths, have been carefully explored, and
for the most part exhausted. The evidences given above, however, promise
the production of tin in large quantities, at depths considerably beyond
those to which our miners have yet penetrated.
CHAPTER II.
ON THE LIMITS OF THE METALLIFEROUS ZONE.
THE "sermons in stones" which are written on the geological tablets of
the book of Nature have been the subjects of study to many of the most
intellectual minds which adorn the lists of Science.
A geological section-carefully drawn from the most recent observations
of some of our best field geologists-instructs us that the formations of which
we have any exact knowledge are the—
TERTIARY, OR CAINOZOIC
SECONDARY, OR MESOZOIC
Feet.
Including the Epochs of the PLIOCENE
MIOCENE
have a thickness of 2,750
EOCENE
Feet.
The Cretaceous
The Oolitic, or Jurassic
The Triassic
Carboniferous
3,850
4,000
5,000
20,000)
""
""
12,850
PRIMARY, OR PALEOZOIC
Old Red Sandstone and Devonian. 10,000
The Silurian
The Cambrian
Laurentian
•
40,000 ""
•
20,000
unknown
Total thickness
90,000
105,600
Or nearly twenty miles.
Man has not yet penetrated a mile in perpendicular depth. The greatest
depth reached by the metalliferous miner is at Dolcoath mine, where he has
reached 2,520 feet, or nearly half a mile, and at the Rosebridge Colliery,
near Wigan, the works have reached a yet greater depth. Consequently
it is only under some special condition that we are enabled to determine
the vertical thickness of the known rocks. By the operation of some subter-
ranean forces, acting through countless ages, a series of disturbances have
been effected, by which the beds which are the lowest in true geological
position have been lifted, or tilted, until they appear on the surface of the
Earth. In some instances this uplifting has been due to vast and sudden
catastrophes, in others to slow and silent movements, by the influence of
mechanical powers acting at great depths. We have to deal with these
phenomena no further than they explain those mutations which enable us
to rearrange the rocks in their true order, from the most recent alluvial
deposits, down to the Laurentian rocks, which are, to us, at present the
foundation-stones of our geological system.
The conditions of mineral lodes, and statements of the more important
hypotheses by which the deposition-whether in beds or in fissures-of the
metalliferous ores are explained, have been brought under notice.
The mineralogical modifications of the various rocks in our metalliferous
districts must now claim our earnest attention. As long since as 1814 the
3 I
852
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Rev. J. J. Conybeare* pointed out the general difference between the rocks
in North Devon, and those in the south of that county, and in Cornwall.
In 1823 the same author commenced a detailed account of the Slate
Rocks of Devon and Cornwall, which, however, he left incomplete.†
Mr. Conybeare adopts the following divisions :-
I. Metalliferous, or, more strictly speaking, stanniferous and cupriferous
Slate, including various porphyritic and felspathic rocks (Elvans), and occa-
sionally Greenstone, which he terms the inferior Slate.
II. Slate, called superior Slate, containing no Elvans, but abounding in
Greenstones, especially its obscurer varieties, and in dark-coloured Lime-
stones. Sparingly metalliferous, containing no Tin, but more productive of
Lead than the inferior Slate.
III. Stratified Rock, exhibiting the general character of a conglomerate or
Sandstone, alternating with tender Slate, and occasionally associated with
coraline or shelly Limestone. It contains no metallic veins, and few, if any,
rocks of the Greenstone kind. "This rock might, perhaps, be regarded as
forming the upper part of the superior Slate, and both would probably by
most geologists be termed Grauwacke."‡
Dr. Boase in 1831§ adopts the divisions of Mr. Conybeare, but proposed
to name the Cornish Slates as Porphyritic and Calcareous instead of inferior
and superior. "Most of the rocks of the calcareous series appear to be
referable to the older portions of that class which is intermediate between
primary and secondary, commonly known by the name of Transition." We
have already dealt with the rocks of our mineral districts, and, at page 216,
a section is given which shows the character of the metalliferous and non-
metalliferous beds.
De la Beche remarks || that "the Cornish miner prefers a Granite or
Elvan which is to a certain extent decomposed. The particular character
of the various kinds of schistose rocks, and the harder beds associated with
them, is also carefully noted, and from experience some kinds . . . . are
known to carry more ore than the others, while some again are regarded as
unfavourable."
Mr. J. Carne states that when the copper lodes in Gwennap intersect
the Red Beds they become unproductive, an immediate change taking place
when they pass beyond them into another state. "In most lodes the miners
have their favourite kind of rock, or country, so that the whole tendency of
their experience goes to show that particular mineral structures, other cir-
cumstances being the same, are more favourable to the occurrence of the
ores sought than others." Mr. Carne further observes,¶ "that in Godol-
phin mine the lodes were rich in the Killas (argillaceous Slate) when it was
of a bluish-white colour, but poor when it was black. In Poldice and Wheal
Fortune the lodes in the Killas continued productive until they entered a
* "Memoranda relating to Clovelly." ("North Devon Geological Transactions," vol. iii. 1814.)
+"On the Geology of Devon and Cornwall." ("Annals of Philosophy," 1823.)
Grauwacke. In De la Beche's Report on the Geology of Cornwall, Devon, and West Somerset, at
p. 38, will be found some remarks on the use of this name. See also page 217 of this volume.
"Contributions towards a Knowledge of the Geology of Cornwall." ("Transactions of the Geo-
logical Society of Cornwall," vol. iv.)
|| "The Geological Observer," p. 670.
T "Transactions of the Geological Society of Cornwall," vol. iii. p. 81. 1827.
CHAP. II.]
ROCKS FAVOURABLE TO LEAD ORE.
853
stratum of blue hard Killas which cut out the richer. In Wheal Squire the
copper lodes were very productive when in the soft light-blue Killas, but a
stratum of hard black variety underlying (dipping) rapidly, met one lode at
a depth of 44 fathoms, and the other at 120 fathoms under the adit, and at
these levels both became poor. At Penstruthal copper mine the lode had
been tried unsuccessfully at various times in parts where the Granite was
hard; but trial being made where the rock was soft, it became one of the
most profitable mines in Cornwall."
That these conditions prevail in other countries is certain. One authority
only will, however, be quoted; that of M. Fourney. He states that commonly
in Upper Hungary the richest copper ores are found in the fine Clay-Slate;
that in Saxony the silver ores occur in Gneiss; that in the Hartz certain
ores are intimately connected with Grauwacke. At Andreasberg the veins,
which pass from argillaceous Slate into flinty Slate, lose their riches in the
latter rock. The veins of Kongsberg, Norway, are sterile in Mica Slate, and
become productive in beds known by the name of Faalbænder.
In Derbyshire, where the same fissure not only passes through the Moun-
tain Limestone, often with its associated igneous rocks, but also across the
surrounding and higher accumulations of shales and Sandstones, the lead ore
(sulphide of lead) keeps generally, though not altogether, to the Limestone
series, and appears most prevalent in the upper part of it. At one time the
Derbyshire miners thought that lead veins did not traverse the Toadstones or
blackstones, so unproductive are they. It is now, however, known that Rake
Veins—which are true fissures-pass through those igneous rocks as well
as through the Limestones, the ore being absent where the igneous rocks
constitute the walls of the vein.
Sir Henry de la Beche writes*: "Among the Limestone beds themselves
some are considered more favourable, as walls to the vein, than others, and
certain of them, in which much carbonate of magnesia occurs, are disliked
and looked upon as somewhat unfavourable. Though the veins are known
to be often continued into certain shales, not unfrequently black, and con-
taining much carbonaceous matter above the Limestones, and though those
shales have occasionally borne-as the term is—a fair amount of ores; looking
at the district generally, this is the exception; and it is a still greater excep-
tion when the Sandstones surmounting these shales contain any appreciable
amount of ores, though a fissure may have traversed all these various rocks,
arranged as beds, and have been open to solutions of a similar kind at the
same time. Taken as a whole, the upper part of the Mountain Limestone
series in Derbyshire is the most metalliferous, and in it certain beds appear
more favourable for the occurrence of the ores of Lead than others."
Of the occurrence of the ores of Lead, in spaces between beds, which were
open when they, and the other contents of such cavities, were accumulated,
those at Fawnog, near Mold, Flintshire, are striking examples. Mr. War-
ington W. Smyth informs us that after an unprofitable search for Lead in
the shallow workings between the Carboniferous Limestone and its covering
of arenaceous rocks known as Millstone Grit, it was discovered that ore was
abundantly distributed in a flat or streak of ore between the rocks.
"The Geological Observer," p. 682.
3 I 2
854
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
To quote De la Beche again: "Not only are certain minerals, including
the ores of the useful metals found in a fissure, more frequently adhering to,
or accumulated near, particular rocks, or modifications of the same rock.
but also in some districts, where more ores than one occur in sufficient
abundance to be profitably worked, so that the ground is well explored,
fissures in given directions are observed to contain certain of those minerals
more than others."
Mr. W. W. Smyth remarks: "The metalliferous district of Cardiganshire
and Montgomeryshire is a tract of land .. .. formed exclusively of Clay-
Slates, and Gritstones correspondent with or underlying the lowest beds
described by Sir R. Murchison in his 'Silurian System.'"* And again he
continues: "The presence of ore cannot here be directly ascribed to the
proximity of Granites or Porphyrites, since this happens to be the only
large portion of the Slaty rocks of Wales, in which not a vestige of any
rock of igneous origin is met with. Moreover, whilst their occurrence in
the bed of only one epoch renders it impossible to fix their geological age,
the various direction of the lodes gives no clue towards the determination
of their relative age."
The great mining districts of Alston Moor and those of the northern
counties are thus concisely described by Mr. William Wallace :-
"The groups of the newer Palæozoic rocks, consisting of the Mountain
Limestone, Millstone Grit, Coal Measures, and New Red Sandstone, repose
conformably on the Old Red Sandstone; and in the North of England,
excepting the last, they all pass into each other by regular alternations, and
are well developed in the tract of country, about 60 miles broad, lying on
the west side of a line drawn from Nottingham to Berwick-on-Tweed, a dis-
tance of about 200 miles." This comprehends the mineral district of
Northern England, which has been for a long period remarkable for its
production of lead ores. Mr. W. Wallace, in his "Mineral Deposits,'
urges an hypothesis, that all the lead mines in Alston Moor of a productive
character have been found above the present watershed of the country.
There are a few exceptions to this rule, where profitable lead-mining has
been carried on in the Lower Limestone stratum. This hypothesis, however,
lends its support to the fact, that the deposits of lead ore do not extend to
any considerable depth, and, as a rule, the large masses of galena have been
discovered at comparatively small depths from the surface.
It would not be difficult to increase considerably the evidence which goes
to show that certain rocks are generally metalliferous, whilst others are
almost invariably not so, and that the geological situation of the rocks
appears to determine their metal-bearing character. The occurrence of
detrital tin in the valleys, on the modern seashores, and rivers certainly
proves the existence of large tracts of land which have been removed by
denudation. Tin lodes which we detect in our mines must have extended
originally into the rocks which have disappeared by denudation. All the tin
and all the gold (at one period the precious metal without doubt occurred in
large quantities) found in the tin streams must have been derived from these
*"On the Mining Districts of Cardiganshire and Montgomeryshire." By Warington W. Smyth,
M.A., F.R.S. ("Memoir of the Geological Survey of Great Britain.")
CHAP. II.]
LODES OCCUR IN PRIMARY ROCKS.
855
veins, which have been through ages gradually worn down through natural
causes. The tin lodes of Cornwall have been generally found near the surface,
as at Dolcoath, Tresavean, and numerous other mines. Copper has been dis-
covered at greater depths below the tin, showing that some remarkable muta-
tions have occurred. Whatever hypothesis may be adopted, it is certain that a
new set of conditions must have taken place to produce in the same fissure, a
deposition of copper ore below that of tin. We have not the remotest idea
of the character of the change; it would be, therefore, idle to venture on
any speculation respecting it. The lode in Dolcoath mine, as already stated,
shows yet another remarkable change at a still greater depth. Below that
portion of the lode containing the copper pyrites, a rich deposit of tin has
been again formed, and this stanniferous vein continues increasing in its
productive state to the extremest depth explored. An idea prevailed amongst
the old tin miners that Granite was a rock which was not conducive to the
deposition of copper ore in its fissures. De la Beche writes: "Not many years
have elapsed since it was held good doctrine that no copper ore, in profit-
able quantity, could be found eastward of Truro Bridge, and the existence of
such mines as Crinnis and Fowey Consols have been, would have been con-
sidered highly improbable, and consequently it would have been thought a
wanton waste of capital to have embarked in the search for copper in that
neighbourhood; yet a very ordinary amount of geological research would
make it appear that the conditions which accompany many of the lodes near St.
Austell are very similar to those in the great cupriferous district of Gwennap."
The occurrence of tin and copper in Granite and in Elvan, regarding them
both as rocks which have been to a greater or a less extent subjected to
igneous action, and to have been forced through the superincumbent strata,
may admit of some explanation. These rocks, when in a semi-fluid or plastic
state, were forced through the Slates or Sandstones, when these were yet
thoroughly impregnated with metalliferous matter. This would naturally
find its way into the Granite or the Elvan, and either in the fissures or in
the solid mass of these rocks during the slow process of consolidation and
crystallization. The metalliferous minerals found in these rocks must,
therefore, be regarded as belonging to the age of the rocks into which, or
through which, they have been forced.
This is also perceived to be the case with the small metalliferous veins of
Derbyshire, which are near the Toadstones of that county.
It is not desirable in the present state of our knowledge to extend this
portion of our inquiry, especially as the space at disposal has become very
limited.
All the evidence given tends to prove that the metalliferous ores which
are useful to man have been discovered in a certain class of rocks of a well-
marked character. In the Tertiary or Cainozoic rocks there is an almost
entire absence of metalliferous minerals excepting iron, and the ores of this
metal have been clearly introduced by infiltration.
In the Secondary or Mesozoic formations a similar set of conditions prevail.
In many of the strata, very extensive deposits have been found and worked.
But the discovery of the ores of any of the other metals must be regarded as
unusual and, generally, accidental.
856
FUTURE PROSPECTS OF BRITISH MINING. [BOOK IV.
In the Primary or Paleozoic rocks we find the Permian group, embracing
the Dolomitic or Magnesian Limestone rocks, and the New Red Sandstone,
and the New Red Conglomerate becoming more and more metalliferous with
depth. The Carboniferous and Mountain Sandstone, with its Coal and Sand-
stone, its carboniferous Slates, all are, more or less, productive of the more
especially metalliferous ores; the same may be said of the Devonian group,
with its various modifications of the Old Red Sandstone series.
We have seen that in the Silurian group of Wales lead and copper have
been found. We desire to quote a passage from Sir R. I. Murchison's
"Siluria,"* which, although it is especially directed to the occurrence of
gold, bears distinctly on the question relating to the depth to which metal-
liferous deposits may be expected to extend: "In conclusion, let me express
my opinion that the fear that gold may be greatly depreciated in value rela-
tively to silver—a fear which may have seized upon the minds of some of
my readers—is unwarranted by the data registered in the crust of the
Earth. Gold is, after all, by far the most restricted, in its native distri-
bution, of the precious metals. Silver and argentiferous lead, on the con-
trary, expand so largely downwards into the bowels of the rocks as to lead
us to believe that they must yield enormous profits to the skilful miner for ages
to come, and the more so in proportion as better machinery and new inven-
tions shall lessen the difficulty of subterraneous mining.†
"It may, indeed, be doubted whether the quantities both of gold and silver
procured from regions unknown to our progenitors, will prove more than
sufficient to meet the exigencies of our augmenting commerce and luxury.
But this is not a theme for a geologist, and I would simply say that Provi-
dence seems to have originally adjusted the relative value of these two
precious metals, and that their relations having remained the same for ages.
will long survive all theories. Modern science, instead of contradicting, only
confirms the truth or the aphorism of the patriarch Job, which thus shadowed
forth the downward persistence of the one and the superficial distribution of
the other, 'Surely there is a vein for the silver. . . . . The Earth hath dust
of gold.'"+
It is greatly to be regretted that the observations of the miners made
through long centuries have not been recorded. Miners are usually excel-
lent observers, but it is rare indeed to find a practical miner who has left a
note either for his own guidance or as a direction for his children. The
experience of the aged miner has perished with him, and his son has to
begin exactly where the father began before him; consequently the advance
made in our knowledge of subterranean phenomena has been exceedingly
slow and very limited. Looking, however, at the evidence afforded, most of
which has been carefully selected, and it is hoped clearly given in this volume,
it all points to the conclusion that the deposition of the metalliferous ores
—whether we regard them as being produced under either of the following
conditions-belong to certain well-defined geological epochs.
* "Siluria: the History of the Oldest known Rocks containing Organic Remains." By Sir Roderick
Impey Murchison, D.C.L., F.R.S., &c. 1854.
. . shows to what an
A note is given, which says: "A recent report from Colonel Lloyd
enormous extent silver may be extracted from Copiapo and other South American mines. This was,
indeed, the view taken long ago by Humboldt."
The Book of Job, chap. xxviii.
CHAP. II.]
AGGREGATIONS AND CRYSTALLIZATION.
857
1. As of Aqueous Origin-that is, produced by water holding metallic
salts in solution percolating through the stony beds, or flowing through,
and filling, the fissures, be they large or small,—already formed in the rocks.
2. As due to high Subterranean Temperature, as they appear to be in many
of the mining districts of California, where hot springs rise charged with
Silica; and as the quartz is deposited on the sides of the fissure, it is found
that gold and other metals precipitate at the same time.
3. As due to the Ejection of Vapours, holding the metals, or salts of the
metals, in solution, or in mechanical suspension.
It appears that all the metalliferous deposits must be limited to the
epochs extending from the Silurian period to the deposition of the Permian
group. So far as the newer rocks are concerned, the practice, based on
the experience of the miners of all countries, has led to the conclusion
that, except for detrital deposits, or for iron ores, it is useless to search in
any district the rocks of which do not belong to the Paleozoic formations.
Whether mineral veins are to be found below the Silurian rocks is question-
able. Sir R. Murchison has the following remarks on this question.
He was evidently thinking of the occurrence of gold when he wrote them
--but they involve the consideration of the presence of copper and lead in
the Silurian rocks: "In the vicinity of some igneous rocks these schists
and calcareous flagstones have been filled with mineral veins. Besides ores
of lead and copper, it will be shown that rocks of this age were rendered
partially auriferous in Wales, and largely so in other countries. One of
the tracts in the original Silurian region, where the Llandeilo formation is
most metalliferous (lead veins), is that lofty and rugged district of Shropshire,
which lies around the village of Shelve and the Corndon mountains, and
which extends from the west of the Stiperstones into Montgomeryshire."
If the principle of the percolation, and circulation of water is admitted to
be a law essential to the deposition of any of the metallic ores, it is quite
certain that no such circulation could go on at depths where the temperature
was as high as that of boiling water. Before 212° were reached the aqueous
fluid would begin to circulate, the heated portion rising through the colder
fluid; and during this circulation the attraction of aggregation, or of some
analogous force—as, for example, the crystallogenic force-would be brought
into action, and the solid deposits formed on the sides of the fissures.
Sir W. Grove remarks, in his "Correlation of Physical Forces ": "There
is scarcely any doubt that the force which is concerned in aggregation (of
crystals) is the same which gives to matter its crystalline form; indeed, a
vast number of bodies, if not all, which appear amorphous, are, when closely
examined, found to be crystalline in structure. We thus get a reciprocity of
action between the force which unites the molecules of matter and the
magnetic force, and through the latter the correlation of the attraction of
aggregation with the other modes of force may be established."
This passage, read in connection with what has been already said in
reference to the electricity detected in mineral lodes, will convey to the
thoughtful mind a tolerably clear idea of the phenomena which, slowly,
silently, but continuously, is ever active in the dark recesses of the rocks.
It must be remembered that, supposing metallic matter to be held in
858
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
suspension or solution in super-heated steam, or in the vapours arising from
the seat of volcanic power, that this would not be deposited until the fluid,
the gas, or the vapour had reached a stratum the temperature of which was
considerably reduced. Therefore the heat of the rocks in situ regulates to a
great extent the probability of the formation of metalliferous deposits. It is
not improbable that mineral lodes may be formed under either of the three
conditions named; but it appears evident that the physical conditions
must determine the existence of definite strata, which may be regarded as a
strictly metalliferous zone.
The extreme depths to which the Cambrian and Laurentian rocks reach,
appear to place them below the region where it is possible that metalliferous
minerals can be formed. We have already mentioned the production of
pyritic crystals in furnaces; but it is thought that these can only be formed
where the temperature has been considerably reduced. It is not probable the
labours of the miner will ever enable him to penetrate to the subterranean
recesses. We have therefore to be satisfied with hypotheses which conform
the most closely to the laws which we gather from our observation of matter
on the surface of the globe. The arguments, based on long experience, and
careful observation, appear to prove that the lowest known rocks are below
the influences which are necessary to the production of mineral wealth.
The conclusion to which, therefore, we are led is that profitable mining
can only be carried on within the limits indicated, which we may especially
characterise as the METALLIFEROUS ZONE.
CHAPTER III.
THE OCCURRENCE OF ORES AT GREAT DEPTHS; OR IN NEW DISTRICTS.
THE preceding chapters will have rendered it evident that the constantly
increasing discovery of metal mines in all parts of the world, and the con-
sequent supply of the requirements of our manufactures by importations
from our Colonies and Foreign countries, must keep down the prices of the
metals.
All our mines are rapidly getting deeper, and becoming, at an increasing
ratio, more expensive to work. There are, therefore, two elements which
materially affect the future of British mines-
1. Are we enabled by our present knowledge to say if it is probable that
our mineral treasures will extend to any considerabe depth beyond that
which we have now reached?
2. Are there any districts unexplored from which any largely increased
supplies are to be expected?
Those who have read the preceding pages cannot fail to have arrived at
the conclusion, that all the evidence given strongly supports the view that the
production of tin from detrital deposits in Cornwall and Devonshire is almost
at an end. The "Stream Tin," as it is still commonly called-obtained from
washing the deposits in estuaries, rivers, and foreshores-is now derived,
principally, from the dressing-floors of tin mines. Under the most favourable
circumstances, it has been shown that fine particles of black tin are con-
stantly being carried away by the waste waters flowing from the mines. The
necessity for using clean water for the final operations of dressing has been
already insisted on. Yet even when this is strictly attended to, minute
particles of black tin (tin ore), adhering to atoms of Clay-Slate, or other
rock, will float away, and are eventually deposited with the mud in rivers,
or estuaries, or shores. By the influence of air and water—and especially by
the changes of temperature-the tin eventually separates from the earthy
matter, and in the still water, slowly falls in obedience to the laws of
gravity.
By improvements in the dressing processes no doubt much tin may
be saved, and considerable economy effected in the processes employed.
In theory, it should be possible to take the tin stuff, directly from the stamps
grate, and allow it to pass over the dressing apparatus-carried onward
by the water flowing at different rates, which should be of easy adjustment
-until black tin alone remains to be landed in the "burning-house" for the
separation of the arsenic or sulphur, and the oxidation of the iron. The
removal of the iron and the thorough cleaning of the tin is a process
requiring care; but it appears to be a simple one, for which the ingenuity
860
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
of our mechanics should devise complete machinery. Every time the tin-
stuff is handled, be it by boy or girl, the cost of the "dressing" of the ore
is increased. By automatic machinery this might be avoided, and consider-
able saving secured. All that has been said in reference to the dressing
of tin applies equally to copper and lead ores. The difficulty with these,
especially with the ores of lead—is in removing from the galena the sulphides
of zinc, copper, and the iron pyrites-which are frequently mixed with the
sulphide of lead in the ore. Jigging machinery has been introduced, and
described, which effects this separation partially; but the specific gravity of
the minerals is so nearly alike that some delicate arrangement is still
required to render the separations complete.
To return to the question of the depth to which we may penetrate the
Earth's crust with a probable expectation of finding metallic minerals in
sufficient quantity to pay for their extraction, the answer must continue to
be to a certain extent conjectural.
We have shown that it is a fair deduction to assume the existence of a
metalliferous zone, within which are confined those ores which are of com-
mercial value.
We have endeavoured to make it clear, that between the Permian and
the Lower Silurian rocks, there exists a series of strata in which the ores of
the useful metals are generally deposited. There are some metalliferous
minerals, and many earthy ones, which are discovered both above and below
this hypothetical zone. Iron ore is a striking example of this; being found
in the most recent as well as in the oldest deposits. This is, without doubt,
due to the general diffusion of the oxides of iron in all rocks, and its ready
solubility in water charged with carbonic and other acids. By waters per-
colating through the fissures in the rocky beds, the minerals may be carried
to any depth, and deposited in any stratum, irrespective of its geological
age. Manganese to a certain extent resembles iron, and consequently we
find the ores of that metal near the surface, and at nearly all depths reached
by the miner. Zinc ores are found in the iron ores of Northampton and in
the older rocks of Central Europe.
The metalliferous zone, which we have ventured to suppose exists, is of
such a thickness that no miner will ever penetrate to its lower beds-that is,
supposing them to lie undisturbed in their geological order of arrangement.
We know, however, that owing to the vast mutations to which the superficial
crust of this planet has been subject the order of deposit has been consider-
ably altered, and, therefore, that the lower rocks may be found coming up
to the present surface. This, of course, leads to great irregularity, and con-
siderable knowledge is required on the part of the miner to determine when
he passes from a metal-bearing rock to one which is not productive of ore.
The facts, as we know them, are that our miners have penetrated, in a few
cases, to nearly half a mile, and they find the lode which has been traced
-in Dolcoath to that depth-is at first a tin lode; the fissure then became
rich in copper ore, which gave place to tin in depth, and continues purely
stanniferous. The lode, too, is typical of the district, and in many of the
mines around Carn Brea conditions exist which fairly lead us to expect that
the lodes in depth may prove as rich for tin, as the lode referred to is proving.
CHAP. III.]
UNEXPLORED MINING DISTRICTS.
861
At Tresavean mine the lode in Granite continued well defined down to about
the 300 fathoms level, then it was almost suddenly lost-that is, the yellow
copper ore, instead of being confined within defined walls, as a lode, was dif-
fused through the Granite rock itself. Similar conditions have been observed
in other mines, although not to the same depths. At both Dolcoath and
Tresavean mines, the upper portion of the mineral vein produced tin; then
copper ore came in; and, in the first-named mine, tin again occurs below
the copper ore. The Granite rocks in which the copper ore and the tin of
the mines named occur can scarcely be said to find a place in the metal-
liferous zone, since they penetrate from great unknown depths, and pass
through the upper strata. They and the Elvans are interfering causes,
which may, however, be fairly brought within the hypothesis, in favour of
which the argument has been supported, by supposing that the varieties of
those rocks known as "The Miners' rock" belong to another order than
those which are commonly employed for building purposes-one variety
being friable, coarse, and fissured; the other being coherent and enduring.
By referring to Capt. Charles Thomas's remarks, this will be more clearly
understood.
It appears probable that tin, which has been one of the most superficial
of the metallic ores, will be found to a considerable depth below the level
of the subterranean exploitation of existing miners. Copper, on the con-
trary, would appear to be more limited in its range, and probably will not
be found, as an ore, at depths far below those reached, in quantities which
will pay for the increased cost of raising it. Lead is in all probability
limited to the Limestone rocks and to the Clay-Slates. Mr. Wallace, from
his examination of the lead lodes of the North of England, was led to
advance an hypothesis that the lead deposits were always found above the
present water-shed of the country. Although this is partly true with regard
to the Alston Moor district, the hypothesis has not been supported by the
conditions of lead lodes in other localities. Still, the inference which
appears the most reasonably drawn from the study of the lead lodes of
Cornwall, of Wales, and other districts, is that they do not penetrate the
Earth's crust to so great a depth as tin does.
It is difficult to answer the question as to the probability of these being
unexplored districts which are deserving the attention of mining adven-
turers. The miners of these islands have been for more than two thousand
years employing every natural method for discovering mineral veins, and
many supernatural ones have been called in to aid them. Therefore there
scarcely remains a piece of ground, in any mineral district, into which they
have not pushed their searches. In Cornwall and Devon it has been found
that all the productive mines have been found near the junction of the
Granite and the Clay-Slate (Killas). An examination of the geological maps
of those counties will show that by far the largest number of mineral lodes
are discovered near the junction of dissimilar rocks, and that as we extend
our inquiry away from the lines of junction, the lodes diminish in number,
and the value of those disclosed becomes less and less, with an increase of
distance. There will be found, however, that there yet remains some few
districts, in which such conditions prevail as are supposed to be favourable
862
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
to the production of the ores of the metals. It would not be prudent to name
any of these, since such indications might lead to expensive searches, which
would only end in loss and disappointment. All the conditions under which
veins of a productive nature are known to occur have been already described.
A careful study of those will prove to be the most reliable guide, for any
adventurer, in this always uncertain field. In the present state of our
knowledge, experience alone must be our guide in searching for mineral
veins, and for determining if the lodes found are sufficiently promising to
warrant the expenditure of capital in exploring them. It would be an
interesting experiment to obtain, by general subscription, a sum of money
sufficient to sink a deep shaft, some few hundred fathoms deeper than any
one at present sunk, in a carefully selected district, with a view to the
examination of the geological and physical conditions of the underlying
rock, and to determine the character of the fissure veins, or other mineral
deposits, which may be discovered at these extreme depths.
•
CHAPTER IV.
IMPROVEMENTS AND ECONOMY IN WORKING BRITISH MINES.
THAT the British mines may be worked, and the ores prepared for the
smelter, at less cost than is usually the case at the present time, is beyond
all dispute. In every division of the miner's labours there is room for con-
siderable improvement. We have recently seen the advantages derived
from the use of the boring-machine, the employment of which is gradually
extending.
So considerable a space has been devoted to the description of
these machines, that nothing remains to be added to the matter already given.
The introduction of the new explosive agents has led to much economy in the
sinking of shafts and the driving of levels. The advantages of the mechanical
borer, and the more powerful explosives, may yet be considerably extended.
Ventilation becomes more important as we carry out the more rapid
processes of exploration. It will be seen, from the evidence already given,
that very great differences of opinion exist as to the chemical condition of
the air after the employment of various kinds of explosive agents. The
senses must not always be relied on as giving correct evidence upon this
point. The chemical examination of the results of combustion should be
alone depended on as a guide. The decomposition of nitro-glycerine, of
dynamite, and of explosives belonging to that class, produces gases which
are invisible, and extremely insiduous, which cannot fail to be injurious if
frequently breathed. The inspiration of the air containing the products of
the nitro-glycerine compounds has been often found to produce unpleasant
sensations in the head, and in extreme cases, noises in the ears, with, some-
times, bleeding of the nose. Therefore machines for ventilating our metal
mines,—of a more perfect form, and more simple in their operation, than
those now in use,-should be introduced. The means of ascending from the
bottom of our deep mines should be rendered more effective and less labo-
rious than they now are, and the descent of the miners should be facilitated
without introducing new elements of danger.
With a view of obtaining the best possible information on the question
of working our mines more efficiently, and with greater economy, letters
have been addressed to miners of known ability, and of great experience,
and to the proprietors of mines who have long been acknowledged as the
best authorities. The following replies have been selected, from a consider-
able number of letters received, as being of considerable interest.
Suggestions for working economically Tin and Copper Mines of Cornwall, by
an experienced Miner.-1. The Miners should relieve underground, and
generally three cores in twenty-four hours should be adopted.
2. In mines of any considerable extent,-say beyond a depth of 50
864
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
fathoms-it would be advisable to send down and draw up the men by
means of a small horizontal steam-engine and "gig" running on guide
ropes, as at the Minera lead mines in North Wales, where, during the last
twenty years, the same apparatus has been employed sending up and down
from 300 to 500 men daily. In fact every facility should be given to the
men to get to their work quickly, and without suffering fatigue.
3. The disposition of adventurers and mine agents should be to increase
rather than to decrease the rate of wages, and thereby to insist upon more
work and the production of a still better class of workmen than exists at
present.
4. The tribute system,-particularly in poor and extensive mines,-ought
to be encouraged to the fullest extent, since each individual tributer may
be considered as an independent adventurer, exercising his individual
judgment, and as having a keen and direct object in discovering ore, and
sending to surface not only the orey stuff he may discover, but also free from
worthless "deads," thereby saving hammering, drawing, and dressing
charges. In fact, poor and extensive mines may continue to work for many
years on tribute, paying cost and making more or less profit, which could
not exist for six months without incurring a heavy loss if worked on Tut work.
Materials.-5. The steel should be of the very best quality, and the
"points" thoroughly well sharpened and tempered. In fact, so important
is this subject that it would be well to offer a premium for—
(a) A stove or furnace in which the tools should be heated at the
proper temperature, and never overheated or burnt, for sharpening.
(6) A tool-sharpening machine.
(c) A tempering oven.
At present, one smith will sharpen and temper steel well, another badly.
Soft burnt, or badly-tempered borers, will seriously diminish the aggregate
depth of hole which can be bored per core-render the general progress of
work much slower, and increase the cost of the work itself, throwing a larger
increment of the "dead" upon the exploratory cost.
6. The object of the miner should be to minimise the boring labour by
substituting explosives, so far as it may be economical to do so. Small
holes should be bored at the bottom so as to be not of greater diameter
than the dynamite cartridge used.
A hole two inches diameter, bored to required depth, will take about four
times the length of time and power to bore, as a hole one inch diameter to
an equal depth.
Railways.-7. The "ways" should be well laid and maintained, the
waggon wheels properly greased and set upon the axles, and the wheels for
any considerable traffic provided with oil boxes.
Pumpwork.-8. The pump cisterns should be kept clean, the holes in the
windbores open, the plungers well attended to, the buckets and clacks pro-
perly maintained, and the rubbing pieces frequently smeared with grease.
Engine.-9. A system of indicating the engines once in two or three
months might be advantageously adopted, and the old rivalry between
engineers, by reporting the duties performed by the engines, should be
restored if possible.
CHAP. IV.]
CHARLES FOX ON MINING.
865
Pumping. As the mines must necessarily get deeper, and greater com-
parative cost incurred in pumping, every care and consideration should be
given to the engine with the view of realising a greater unit of power, from
a given weight of coal. With this object the coal should be of the
highest calorific value.
It should be fresh and dry, free from shale or dust.
It should be properly distributed on the fire-grate.
The boilers should, as far as possible, be fed with pure and non-corrosive
water.
The boilers and flues should be cleansed at stated intervals.
The boiler flues should throw the heat on the boiler shell, and not in any
way open to allow the heat to "run" or flow through into the rubble work
or masonry.
The boilers should be efficiently covered, to prevent the passage of heat
from the upper part of the shell.
The feed-water should be taken from the condenser as hot as possible.
The steam pipe should be effectually covered.
The main pistons should be packed when necessary.
The valves ground to the seating when required.
A vacuum gauge fixed between exhaust valve and condenser.
The late Mr. Charles Fox, of Falmouth, who all his life through
exhibited the utmost interest in improving the condition of the Cornish
miner, and to whom we are indebted for the introduction of labour-saving
machines into the Cornish mines, in reply to some inquiries said:
"The great difficulty is to get the attention of minds so focussed, and thus
practically brought to bear, on mining arrangements, as to promote reform."
With this introduction he handed the following Mining Memoranda :-
"Leases should include a larger extent of ground, and be less diffuse. If
lessees were allowed, on building dwelling-houses for agents or miners
thereon, to hold them for a term of years, as well as cultivated plots,
encouragement would be given thus to promote the welfare of the miners
and to keep them near their work.
"Mines are overcome by water (or in danger of being so) when
adjoining mines are in different stages of progress or prosperity. These
should be rendered more or less mutually dependent-the Setons for
instance. Such mines as Dolcoath and Cook's Kitchen should have been
one concern. With more ground a larger engine might be erected, and a
relatively larger engine-shaft be sunk. Now the cost is greatly increased
from separate establishments of 'plant,' &c. The fixed machinery, dressing
apparatus, carpenters' and smith's shops, counting-houses, &c., are multi-
plied, and in many, if not in a majority of cases, ere long abandoned.
"Central chemical or metallurgical works (not in a mine partnership), for
dealing with the mixed ores of various mines, could render advice on the
advantageous treatment of them where adventurers in individual mines
would not incur the cost of experimental works. Our mining students might
then benefit by a practical experience in such a treatment of our ores as is
now carried on in Newcastle, and other Mining Schools.
866
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
"The price of copper admits (1872) of a fair profit, if discoveries of new
lodes of moderate produce were made. The high price of tin for a few years
checked the opening of copper mines. There are still large fields only
partially explored about St. Just, Marazion, Godolphin, the North Coast,
St. Blazey, Bodmin, Liskeard, Hingston Down, &c.
"Where the ground does not admit of a deep adit being rapidly driven by
a boring-machine, traversing various strata and intersecting all lodes, the
erection of an engine on an abandoned shaft, which might pump the water,
draw the stuff from one end, and work a boring-machine, might enable
adventurers at a small outlay to 'anatomise,' as it were, the very viscera of
the region, by penetrating them at the rate of 300 to 500 yards in a year.
"It is the fast pace that cripples or kills the horse, the slow that knocks
the ball (Mine).
"You harpoon the whale, and he is yours; you might wound him with
knives from head to tail, and get a blow from his tail, and your lot be worse
than in the Vice-Warden's Court.
"If dispatch in opening copper mines be needed, how much more in tin
lodes (generally in harder ground or of a harder nature), and having to
contend against a reduction of price of more than 50 per cent. Pitches of
low produce, where the tin-stuff may be broken for 3s. or 4s. per ton, must
be passed by, as it will not under ordinary circumstances pay all the
charges. If the leading captains would note the distance which often
separates a good piece of tin ground from another,-calculate the time
required to cut a side lode at a much deeper level than that at which it was
promising nearer the surface,—or the time needed to sink the sump 10 fathoms
to get more backs, they would add the weight of their testimony to the vital
importance of assisting manual labour in driving levels and sinking shafts
by machinery, at once purifying the ends and preserving the heart and lungs
from excessive exertions under damaging circumstances.
"Registers should be kept in each mine of all the men working under-
ground, date of birth, their ages on first working below the surface, and
how often under medical care. There should also be a medical register kept
in each mine.
"An accurate comparison of the relative advantages, or disadvantages, of
ordinary stamps, as compared with pneumatic or spring stamps, is greatly
needed, also of the cost of working locomotive stamps, such as might return.
accumulations of halvans, or tin-stuff raised from shallow backs. There is
reason to doubt if the breaking machine is sufficiently used, enabling a
cleaner picking of coarse work, so as to diminish cost of stamping, bud-
dling, &c. Dingey's pulveriser may be most useful. Should not a compe-
tent captain be appointed to compare different modes of dressing ores,-
especially those of tin, or of tin mingled with blende or copper pyrites,-
whether in the many modes of buddling, Froude's or Taylor's separators?
The rotatory calciner has a strong claim over the costly ovens, demanding
much labour and care.
"It will not do for Lords to forbid selling tin in the stone. They may thus
stifle a mine at its birth, before adventurers have any certain data to warrant
the erection of machinery.
CHAP. IV.]
EDUCATION OF MINERS.
867
"If the tin-stuff be carefully spalled, and a selection be made of its better
work, the carriage to the buyer's stamp at a moderate distance would be
expedient, and encourage numerous trials. There are some mines in which
there are ample spaces for lodging attle instead of hauling it to grass.
"The steady price of lead should encourage a much more diligent search
for lead lodes than is now the case in Cornwall; they will be found most
numerous away from the copper and tin lodes.
“Alas, how much ought to be done for the further education of our working
miners to make them skilful labourers, either in mining or in kindred
pursuits, such as smelting, or being useful in various chemical processes. To
engine and pit men,-in some of the responsible positions in the construction
of railroads, ever stretching more and more over the globe,-some know-
ledge of hydrostatics is ever found useful, both in mining and in the various
public works, in which an intelligent miner will be always valuable, both at
home and abroad. But our present funds are not sufficient to teach the very
elements of some of those branches of learning,* which they are eager to
cultivate if properly aided. Plane geometry should be sedulously studied;
a practical knowledge of electro-magnetism opens a fair field for employment
for young men. R. W. Fox has shown that it reveals hidden secrets under
ground-the true divining-rod. Not later than 1838 he discovered that the
Earth completes the circuit, otherwise two cables would be needed between
two continents; and doubtless the electrometer might show if two bunches
of ore, at some distance from each other, had a metalliferous connection and
were separated by barren rock.†
"I have often imagined that the subject of alloys offers an illimitable field
for research that practically we know but little of the extent of the uses of
tin if alloyed with different metals in various proportions."
:
A most experienced mine agent, who, although an imperfectly educated
man, had, by his powers of observation and the application of his acquired
knowledge to many useful ends, been a valuable adviser, furnished shortly
before his death the following notes in answer to sundry inquiries made :-
"You inquire respecting the cost of raising and dressing ores of tin and
copper at per ton. This is a very difficult question to answer, as scarcely
two mines are alike. It seldom happens that the different levels in driving
or stoping are similar. 1st.-In some mines, the rock is very hard to break;
in others, much more decomposed ;-the cleavage is often much better in one
mine than in another. Sometimes, in consequence of the ventilation being
bad, the price for breaking varies, so that it is charged from £2 to £30, or at
The
even more per fathom; and as it is with levels driving, so with stopes.
distance of the workings from the shaft, for the removal of the stuff, also
makes a difference, as we have to pay more for wheeling or traming.
"The average price per ton in our mine, for breaking and bringing to
surface (as the contractor is supposed to pay all cost) is about 7s. per ton,
but even then the averages of two months are not alike; but in some other
mines it would be only 2s. Again, the tin-stuff varies as to quality; one
* Mr. Charles Fox refers to the expenses of teaching science in the classes of the Miners' Association.
+ See Mr. Robert Were Fox's Experiments, pages 222 and 389.
3 K
868
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
ton broken in one place at 9s. per ton produces only 28 lbs. of black tin to the
ton of stuff; at another place, at the same price (9s. per ton), it produces
12 cwts. to the ton. So that as it regards price and produce we can say but
little as a guide for other miners.
"As to the dressing of tin ore, this also differs considerably in its cost.
In the first place, the stuff is drawn to surface small, because of its being
more decomposed, or with a more favourable cleavage, so that it requires
little or no 'spalling'; in the other case we have to pay 6d. per ton for spal-
ling. The distance to carry the stuff after being spalled to the stamps makes
a difference also.
"Again, tin-stuffs have frequently a quantity of pyrites, or sometimes
wolfram, or other foreign matter mixed with it, in greater or less quantities,
so that some tin-stuffs pass through the dressing process with one-half the
trouble, and consequently less cost. Again, the more pyrites in the ore the
more coal is required to calcine it.
"Much also depends on whether you apply water or steam power to
drive your machinery. This may apply also to the breaking, and dressing
of copper or tin, only the cost is not near so great for the former as for the
latter. Tin-dressing with us, in consequence of so much foreign matter, costs
us 6s. per ton of stuff, while tin at other mines may be dressed for 2s. per
ton.
"To make a mine pay in these times the greatest attention must be paid
to the machinery. I have known parties carry their economy too far; through
the want of a little attention to the lapping of the joints underground, the air
enters, and the engine performs only half duty, and frequently in some shafts
the friction is unduly great around the main rods, which means cost of coal.
Our Cornish engines should be made to do better duty also, but the
managing agents have other property to think about, and the working
engineers are not allowed to think in many places, so that there is a larger
quantity of coals consumed than ought to be. In our mine I have long
contested this point, and it is only recently that I have been improving slowly
our steam stamps. We are now saving about 20 tons of coal per month
by properly adjusting the gear, without any new arrangement.
"At our drawing, or winding, engine I long advocated a better piston
and expansion gear; the engineers said, no good would be effected, but I
have had it done, and we save now at that engine about 20 tons of coal per
month. Great attention to the keeping of machinery in repair well pays
for the outlay."
The question is frequently asked, Is British mining a remunerative
pursuit? Various replies might doubtless be given in accordance with any
particular set of views and opinions held on the subject; but mines promoted
by mere speculation can scarcely be expected to become profitable, inasmuch
as they are too frequently grounded upon a misrepresentation of facts, while
the capital connected with them is often largely diverted to the pockets of
individuals whose main purpose is immediate gain. Further, the manage-
ment or conduct of affairs is often leavened with ignorance and incompetency;
the acquisition of personal gain, at the cost of unsuspecting shareholders,
being unfortunately sometimes the rule of action.
CHAP. IV.]
CAPITAL AND PROFITS.
869
If, however, the matter be treated as an industry, in which care in select-
ing the properties, and ability, skill, and economy in working them, are to be
exercised, in such case it is beyond doubt that mining may, on the whole, be
rendered a profitable pursuit.
The following particulars are the actual results of working eighty-eight
tin, copper, and lead mines in the United Kingdom, during a period of thirty-
seven years, the technical operations having been under a general manager,
distinguished for the purity of his character, his excellent businesslike
abilities, and singleness of purpose :-
Year.
No. of No. of
Mines Mines
at work closed
in Year. in Year.
Total Amount of
Capital invested.
Annual Amount of Annual Amount of
Profits divided. Capital invested.
Amount of Capital
returned from Mines
abandoned or sold.
S.
d.
£ S. d.
1819
6
1820
6
6,649 6 5
25,868 18 10
7,680 o O
80
£ S. d.
19,219 12 5
£
S.
d.
7,862 18 5
41,988 14 10
1821
67,857 13 8
18,680 o
20,427 2 4
1822
8
88,284 16
O
41,320 O
12,588 5 2
1823
14
100,873 I 2
50,304 0
104,383 6 2
1824
19
205,256 7 4
49,440 O
163,439 9 8
1825
24
368,695 17 I
87,398 4
145,677 3 2
1826
24
514,373 0 3
54,208 3 2
1827
24
540,803 18 5
1828
24
536,099 5
1829
24
1830
23
1831
18
421
534,736 13 7
73,929 I 3
70,889 6 9
40,720 10 8
30,430 18 2
6,255 7 4
4,000
10,960 0
6,127 7 10
7,500 0
84 4 II
7,035 8
507,038 5
27,471 9 8
21 18 8
2,060 0
I
1832
17
484,334 4
478,486 12
2
1833
18
3
1834
16
1835
17
I
1836 24
478,152 8 10
401,829 0 I
408,387 O I
373,582 O I
36,399 13 3
34,082 12
43,025 10
56,860 5 10
37,410 9 3
320
5,222 8 6
2,340 15
7
275 19 8
1,680 0
8,820 o
3,340 O
1837 26
1838
1839 27
385,566 o I
69,749 O
38,832 0
27
1840
26
164
I
397,836 O I
32,250 6 6
381,606 12 6
1841 25
3
1842
24
1843
24
1844 23
1845 24
1846
2I
1847
1848
22
22
1849 21
1850 29
1851 32
1852
1853
1854
1855
wwww....
33
35
3H 2 332 +HHHM +
376,054 0 O
314,214 O
о
298,599 13 7
82,914 7 6
41,980 o O
O
24,740 O
17,144 15
I
303,424 I I
13,340 0
7,420 O
5,195
11,984 O
12,970 O
12,420 O
17,115
13,828 16
15,416 O
24,709
11,694 10
560 0
O
I, 105 O
O о
700
8,219 0 O
6,220 12
66,804 13
6
2,086 8 6
O
1,175 O O
265 I
280,628 II I
280,563 II I
278,337 7 I
269,693 12 6
4
261,381 12 6
21,500 O
30,601 12
33,596 15 5
23,800 0 0
13, 189 12
8,434 O
2,394 8 O
3,416 O
1,677 6 10
5,442 O
5,378 19 3
I
224,376 14 1O
19, 147 о
042
12,688 O
3,766 13 8
I
241,603 2
7
22,454 8 II
I
274,995 II
6
21,321 оо
20,982 3
29,784 0
35,538 o
35,134 O
1,672 10 4
14,170 6
3
286,913 5
26,702 3 4
44,337 O
4
307,082 5 6
22,425 16 8
46,462 10
36
359,370 5 6
26,294 8 II
34,082 10
36
385,058 15 6
53
24,601 3 4
1,344,266 15 5 1,020,483 10 4
46,469 I 6
792 8 10
408 I I
O
O O
4,357 7 6
3,193
5,850 4 9
2,681 10
6
173,364 15 10
I.
The total amount of capital invested in eighty-eight mines was
Less capital raised on fifty-three mines stopped and accounts closed.
Capital invested in thirty-five mines .
£
832,234 4 5
447,275 8 II
s. d.
384,958 15 6
II.
Amount of capital returned from mines abandoned or sold
Total amount of profit realised and divided on eighty-eight mines to years
1855 inclusive
1,344,266 15 5
173,364 15 10
Total amount returned on £832,234 (capital invested)
1,517,631 11
1 3
3 K 2
870
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
III.
Total amount of profit divided on fifty-three mines abandoned or sold
Amount of capital returned from fifty-three mines abandoned or sold
Capital invested in ditto
Net profit over and above the return of the capital sum
S. d.
£
819,125 15 2
173,364 15 10
992,490 II O
447,275 8 I
545,215 2 II
It will thus appear that the return of money on the total capital invested,
£832,234, exceeded the latter sum by (£1,517,631 11s. 3d.-£832,234)
£685,397 11s. 3d., and that the profit on fifty-three mines at work, after
deducting the capital, £447,275 8s. Id., was £545,215 2s. 11d. From the
table itself the percentage of profit on the capital for any given year may be
ascertained. Thus in 1823 the profit accruing on fourteen mines then at work
was (£100,873 is. id. : £50,304 :: 100) 491% per cent., while on fifty-five
mines in 1855 it only amounted to (£385,058 15s. 6d. : £24,001 3s. 4d.:: 100)
67% per cent.
A considerable amount of thought has been for many years devoted to the
condition of our mines and our miners. Reflection on the present state of
things renders it exceedingly difficult to suggest any reasonable means by
which we may hope to improve the future of British mining.
It appears certain, as is clearly shown by the above returns, that
mining entered on by the assistance of judgment matured by experience
and honestly directed-is of a far less speculative character than it is
generally conceived to be. After carefully considering all that has been
advanced in this volume, it will be, as we think, clear that there are certain
rules—we must not even yet call them laws-by which an adviser may
guide his clients, either to venture on spending money in search of mineral
veins, in a given district, or to leave untouched the uncertain ground.
In 1856 the late Mr. John Taylor, who was regarded by all as a good
authority, stated before a committee of the House of Commons “that there
were no greater facilities for ascertaining the productive character of a mine
now than formerly. The difference was simply in improved machinery.
Our knowledge was not greater than that of our forefathers." This is the
proper place, after this record of his remarks, to give some notice of the
influence exerted on British mining by Mr. Taylor. At first it was thought
advisable to relegate to a note all that it was necessary to write with regard
to the influence of this individual mind on a great national industry. Careful
reflection has established the advantages to be derived from giving in the
text itself a prominent position to the works of a man who, by devoting the
powers of a well-trained mind to the improvement of a national industry,
relieved it from the pressure of many evils, and established it upon a firmer
basis than had previously been secured for it.
"We cannot here go into the detail of the improvements of various kinds
which he (Mr. Taylor) devised and effected for the advancement of the art
of mining, the profit of the adventurers or the physical and moral well-
being of the men; suffice it to say, that in all respects his administration was
eminently successful, and that he gradually took his station at the head of
his profession."
* Quoted from a Memoir by one of Mr. John Taylor's relatives.
CHAP. IV.]
SUGGESTIONS FOR IMPROVING MINES.
87!
Mr. Taylor was educated as a land surveyor. At an early age he was
selected, by some of the shareholders in Wheal Friendship mine, near
Tavistock, to undertake the management of that important concern. He
introduced numerous reforms in every department. He was fully persuaded
of the superior skill and industry of the English miners, but he did not
attribute their superiority to the absence of scientific training.
"If," writes Mr. Taylor,* "what has become the theme of praise in other
parts of Europe be not applicable to England, it must be either because our
mines do not require intelligence and skill for their management, or that our
miners are not likely to have their intelligence and skill advanced by the
most obvious means of doing so.
"As to the first, it is well known that one effect of late efforts in mining in
England has been to deepen the mines with a rapidity totally unprecedented
[this was written in 1829], to consolidate small concerns with larger ones, to
explore more perfectly the ground in all directions, to adopt means that
might render labour productive of profit, to stimulate the labourer by com-
bining his interests with that of his employer, to watch every symptom with
care, and to employ every device that ingenuity could suggest to overcome
difficulties. It must, then, obviously follow that there is a greater demand
for skill in the conduct of these affairs as the mines are increasing in depth
and extent. Numerous expedients to counterbalance these difficulties are
required; and as the expense increases, compensation must be looked for in
the aids that science may afford.”
Mr. Taylor then points out the need for a School of Mines, the details
of which he arranges under the following heads :-
1. The things most proper to be taught.
2. The class of persons who may be expected to be scholars.
3. The Professors.
4. The situation of a School of Mines.
5. The probable expense of the Institution.
6. The means of providing the necessary funds.
7. The Government or Direction.
*
This plan met with no encouragement at the time, but it cleared the
way for the School of Mines subsequently established by the influence
and energy of Sir Henry de la Beche. Mr. Taylor greatly admired the
qualities which he discovered in the miners of Cornwall and Devonshire.
"If I were to say much of what I think of the talents they commonly
possess, and of the excellent use they make of the means of instruction,
slight as they are, which are thrown in their way, it might appear that I
meant to flatter men with whom I am much associated, and to whom I am
so much indebted. Miners in general are a superior class of men, and, in
the deep mines particularly, the constant exercise of judgment and thought
which is necessary produces a proportionate degree of intelligence."
Mr. Taylor had the management of the mines near Tavistock from 1799
to 1812. He then became the manager of the United and Consolidated
mines in Gwennap, in Cornwall. In 1820 he was requested by the Duke of
Devonshire to superintend the workings on his Grace's mineral property in
* "Records of Mining" ("Prospectus for a School of Mines in Cornwall "), published in 1829.
872
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
Staffordshire, in Yorkshire, and in Ireland. In 1822 he undertook the direc-
tion of Lord Grosvenor's mines in Wales, and in 1823 the Commissioners of
Greenwich Hospital placed their important mines on Alston Moor in his
hands. In addition to those mines in the United Kingdom, Mr. Taylor
was consulted in the management of numerous Foreign mines, and he became
the engineer of several of them.
Mr. Taylor was one of the earliest members of the Geological Society.
In 1816 he was appointed its treasurer, which office he retained until
1844. In 1825 he was elected a Fellow of the Royal Society. He was one
of the earliest and most active members of the British Association for the
Advancement of Science, the first council meeting of that body being
held in his house in Bedford Row on the 20th of June, 1832. He was a
trustee and treasurer of the British Association until 1861, and was also
treasurer for many years of the London University College. One of the
most advanced philosophers of the age wrote of this excellent man:
high estimation in which Mr. Taylor was held by men of science you will
find in every word which they utter concerning him. I never knew a man
so entirely loved and admired, so firm in his judgments, and yet so mild.
He seemed more than a philosopher--a wise and good man."*
"The
The influence exerted by Mr. Taylor on mining generally was most
remarkable, and as it regards Cornish mining was of especial importance.
Every branch of mining was improved, new machinery was introduced,
and the condition of the steam pumping-engines was during his reign so
greatly improved that the Cornish engine became a pattern to the civilised
world. Mr. Taylor's management distinguishes and marks an epoch in
British mining, which is, at the present time, in an analogous position
to that which marked it at the beginning of the century. By honesty
of purpose, by well-directed industry, and by devotion to the business
of subterranean exploration, he restored mining to
restored mining to a healthful and
profitate state. As then an important industry was saved from ruin by
the energy of one mind, so now the sad state of depression-notwithstand-
ing the competition of Foreign mines with our own-which reigns in all
our mineral industries, might be relieved by the zealous efforts of a trained
man, who would keep himself free from the seductions of speculative
adventurers.
The difference observable between the "Then and Now" of mining
cannot be more satisfactorily shown than by the following letter from a
gentleman deceased, who held the highest position as a practical metal-
lurgist in the county of Cornwall, and whose family had for several genera-
tions been the leading spirits in Cornish mining:
"I am much obliged for your letter of the 12th inst., and quite agree with
you in principle on the present state of Cornish mines, and on their not
having improved in conformity with advances for conducting many of our
manufactures in this country. In going into business we have several
*
In the "Transactions of the Geological Society of London" we find four papers on Mines, Mining,
and Metallurgy; in the "Philosophical Magazine" ten memoirs; and in the "British Association
Reports" five important communications, by Mr. John Taylor.
CHAP. IV.]
EFFICIENCY OF MINE AGENTS.
873
important points to consider, viz. first capital, then partners, and next, the
most important of all, management. I think these three comprise the
greater portion of the question of Cornish mining being on its wane. I have
a very small interest in only one or two Cornish mines, and if I say anything
deteriorating I do so with the hope that it may lead others to remedies which
may be for the county's benefit generally. We have plenty of mineral
produce left in Cornwall, but to work it profitably we must have efficient
managers if we intend to retain adventurers' capital, for without their con-
fidence we cannot expect to do so.
"As to machinery, this has been much neglected, as mentioned by Mr.
Richard Taylor last week at the Polytechnic meeting. One of the great
losses to our county I consider the system now adopted of stoping ground,
instead of working on tribute. The new plan opens a door to the gravest
abuses, and ought to be driven out as much as possible. The old Cornish
tributer did more work and benefit for his employers, than I ever experienced
in any system of employment. The tribute workman is a partner, and largely
interested in his undertaking. The question of efficiency of agents is a very
serious one, and ought to be regulated by the manager, aided by a committee
in that important matter, as well as all others. In writing Mr. G. L. Bassett
recently about the boring-machine, I have endeavoured to convey the same
views as expressed in the foregoing, about Cornish mine management and
the dues surrender. The latter I should treat as a business question, and
expect the underground, and the capital, account to be placed in a satisfactory
state. No loans at bankers or uncharged cost."
This was followed-in answer to an acknowledgment of the previous
letter-by the following reply:-
“I am much obliged for your letter of the 23rd and for your kindly
writing me so fully on the state of our unfortunate mining affairs, and
though I, to a great extent, reciprocated your views, yet the question is so
serious, lengthy, and weighty, that with my other engagements I cannot
venture to go into the question to try to assist you in detail. I have for a
long time tried to form some new plan for the advancement of the Miners'
Association, particularly to produce a better class of men for mine
managers." This leads to a few words on Mining Schools—their origin in
this country, and the advantages they offer.
In October, 1838, Sir Charles Lemon, Bart., M.P., issued a circular to
mine agents and others throughout the county. After insisting on the
necessity for scientific instruction, he made the following liberal offer :-
"With a view to ascertain how far there is a real demand for such
(scientific) instruction, I will take on myself the expense and responsibility
of an experiment for two years. If I should find on considering the details
that my plan offers a reasonable prospect of success, and if at the end of two
years the county should take up the subject and carry it forward till my
death, I will endow the institution in such a way as shall afford a reasonable
hope of its permanence."
Subsequently Sir Charles Lemon offered-
1. A sufficient site for building a college.
2. £500 contribution to the building fund.
874
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
3. "I will, as far as I am able, provide that a sum of not less than
£10,000 shall, at my death, be placed in the hands of trustees for the use of
the college, and should this sum prove insufficient for the purpose contem-
plated, I am willing to make it £20,000."
An experimental school was organised at Truro, and three teachers were
appointed in 1839. It was not a success. In 1840, the school was again
opened at Truro: a few pupils only attended. Sir Charles Lemon now
renewed his offer, but owing to sectarian views it was not accepted. In 1853,
twelve years having elapsed, another attempt was made-in this instance
by the Royal Institution of Cornwall; and in 1859 it was abandoned, the
'number of pupils being very small."
In the interval, Sir Charles Lemon proposed to the author of this volume,
-who then filled the office of Secretary to the Royal Cornwall Polytechnic
Society-to endeavour to establish a class of young miners in a school con-
ducted by Mr. John Phillips, at Tuckingmill, near Camborne, the very centre
of extensive tin and copper mines.
The expense attending this experiment-of taking the school to the
miner, instead of compelling the miner to go a considerable distance to the
school,—to be continued for twelve months, was equally shared by Sir Charles
Lemon and Lady Bassett. This proved a complete success. In 1858 the
author addressed a letter to Mr. R. W. Fox, which was read and discussed
at the annual meeting of the Royal Cornwall Polytechnic Society, advo-
cating the organization of a Society which should convey to the miner a
knowledge in the practical application of science, and receive from the miner
the advantages of his experience. From this letter the following quotation
is made:-
"One and all' is the motto of the county, and by co-operation every-
thing is to be achieved. My desire is to show that by a proper union of the
mining interest of Cornwall, they may achieve for themselves the utmost
benefit of improved knowledge, they may collect and preserve the results of
their own careful observations, and they may benefit the commonwealth of
science by furnishing those facts by which alone the philosopher can ever
truly interpret the phenomena of nature.
"The kind of education which the Cornish miner receives naturally
makes him a careful observer, and it is only required that some system
should be introduced to render his observations of the highest value, and
reject the worthless. Habits of close observation are established, the young
man goes underground, and, emulous of being a successful tributer,' he
soon learns to note peculiarities in the rock upon which he pursues his
search for ore. Thus the education of the miner is a continued lesson of
observation.
C
"The miner can give knowledge while he receives instruction, he can
communicate important facts, the result of his observation, whilst in return
he is receiving that training and that additional information which would be
indeed 'a light to his path.'
"On the 26th of October, 1859, a public meeting in connection with
Mr. Hunt's proposal was held in the Town Hall, Camborne. The chair was
taken by Mr. John St. Aubyn, and the Miners' Association of Cornwall
CHAP. IV.]
THE MINERS' ASSOCIATION.
875
and Devon, the fourth and most durable of the mining schools, was
founded."*
The objects of the Association were stated as follows:-
1. To obtain the record of observations by practical men.
2. To promote scientific knowledge among the miners.
3. To consider the means of relieving the miner from the toil of climbing
from great depths.
4. To introduce approved processes employed in other parts of the world.
5. To obtain plans for establishing improved ventilation in our mines.
6. To determine the mechanical value of blasting powders, and to make
known improved methods of blasting.
7. To promote the application of machinery for excavating.
8. To aid the young miner by classes in the neighbourhood of the mines,
with elementary instruction in the facts and principles of mechanics,
geology, mineralogy, chemistry, hydrostatics, pneumatics, and other sciences
connected with mining.
We conclude our notice of this effort to secure for the future of mining
a system of technical education which shall be adapted to the wants of the
miner, and which shall tend to improve in every way the operations of
mining, in the words of Mr. Charles Fox, who was in 1861 elected president
of the Miners' Association for two years :-
"The Miners' Association of Cornwall and Devonshire shall devote
itself to the encouragement and advancement of mining and mine engi-
neering; promote the exchange of information and ideas; secure the record
of the results of experience and observation; devise plans for the education
of the practical miner in the branches of science which bear immediately on
mining; establish local collections which shall illustrate the geology,
mineralogy, and physical phenomena of each district; and by all available
methods aim at the improvement of the great mining interests of England."
In 1862 the author brought before the Society of Arts the subject of the
improvement of the miner's education in the following words, which are
equally applicable now as then :-
"When the powers of the mind have been directed to any peculiar set of
natural phenomena for a prolonged period, we usually discover in hypo-
theses advanced, and in theories more or less supported by facts, attempts to
explain the causes which have been active in producing the effects observed.
There is a curious absence of this in relation to mining. Beyond some very
undefined notions that fire played an important part in the formation of
minerals, or that mineral veins have some analogy to the veins in the animal
body, or the branches of a tree, no hypotheses have been hazarded by miners
proper. A few men, educated in the Schools of the Continent, and two or
three Professors of science in this country, have, it is true, promulgated their
opinions, but until Werner published his theory, they advanced but little
beyond the creations of fancy. It will not be without interest to examine
the causes of this.
66
'The miner has ever been a distinguishable man amongst the hosts of his
brother-men. Working in solitude in the dark recesses of the rocks, he has
* "Remarks on the Successive Mining Schools of Cornwall." By J. H. Collins, F.G.S.
876
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
become thoughtful, with only the dreams of ignorance on which to employ
his thoughts. Hence he has peopled the subterranean world with 'Kobals;'
and even the smothered sounds of waters dropping in some unopened cave
have become to him the realization of the 'knockers'-unkind gnomes, who
mock him in his toils, and who as frequently lead him from, as guide him to,
the mineral mass on which they are supposed to labour. Habituated to
danger, the miner becomes careless of death, and his life is a constant decla-
ration of his belief in fatality. Superstition finds her fitting home in the dark
places of the Earth, and reigns supreme in the dark mind of an untaught
Therefore the dominant Powers to the miner have been the creations
born of ignorance and night. Signs and tokens, lucky and unlucky days,
ill-wishes, evil-eyes, witchcraft and charms, were the rulers of his life.
man.
"Although the influences of ordinary school-education have penetrated
to the most remote mining districts, and produced the usual humanising
effects, yet the miner retains many of the peculiarities which belonged to his
forefathers. Whether we examine the miners of Alston Moor, of the dales
of Yorkshire, of the hills of North Wales, or of Cardiganshire, the scattered
workers of the mines of Shropshire, or the large mining population of Corn-
wall, we shall discover the same general peculiarities.
"As a body, miners may be regarded as a religious class, but theirs is a
religion of the heart, not of the head. They are powerfully swayed by their
feelings, to the repression of the influences of reason. Hence the tendency
to those impulsive manifestations of a religious conviction which are known
as 'Revivals.' Thoughtful we have said they are, but their thoughts flow
slowly, and they have ever a tendency to dwell on the darker shades of
life; while it is with extreme difficulty that they can be brought to com-
municate their thoughts to others. Miners are rarely frivolous, even above
ground; they are especially serious below. The youngest men will express
their dislike of idle conversation or of joking in the mine, while whistling is
strictly forbidden. In the sports and pastimes of a mining village there is
something peculiarly sober; and the celebration of the annual feast, with its
attendant fair, has something of a sombre character about it, in comparison
with agricultural revels.
"A sanguine temperament may be said to distinguish a miner. He is
for ever hoping that stores of mineral wealth are a little in advance of his
labour. Therefore, although in relation to the ordinary affairs of life he is
trustworthy, showing a real love for the truth, he is curiously carried away
from it when describing the state of a mine, and he expresses his hopes
rather than records his knowledge. The exaggerations exhibited in some
reports on mines are often of an amusing character, running, indeed, into
poetical rhapsodies. Many an unfortunate adventurer has, however, to date
his ruin from the day when he gave credence to the hyperbole indulged in.
"From their very childhood miners are trained to observe. As boys they
are employed to separate the valuable ore from the useless stones, with which
it is mixed, and this is often a delicate operation. In their labours under-
ground everything depends upon their careful observations, especially in
those mines where the system of 'Tribute pitches' is adopted; the miner
(Tributer, as this class is called) receiving an agreed share of the profit
CHAP. IV.]
THE ROYAL SCHOOL OF MINES.
877
derived from the sale of the ores, which he breaks out of the lode. Yet their
powers of observation are of a very limited order. Their experience is made
up of a knowledge of peculiarities existing within a confined area. So long
as these repeat themselves the miner's deductions are correct; but vary the
phenomena ever so slightly, and he is at once at fault. This is continually
occurring. Within the circle of their labours a few men will probably arrive
at a tolerably exact knowledge of the conditions existing, and this knowledge
gives them a pre-eminence amongst their fellow-miners as advisers. But
remove one of these men from his own locality, he is rarely able to group the
new phenomena presented to his view; he feels he is ignorant, though he is
rarely so boldly honest as to proclaim it; and he commits himself to state-
ments which are only vague guesses, happy, indeed, if any one of them
proves correct.
"It is interesting to note the unmistakable Celtic manners of the
south and west of England, and then those which have a more directly Teu-
tonic origin, of the northern districts. There are differences in the habits of
life of the man, but the idiosyncrasies of the miner are the same.
This may
be due in part to the intermixture which has taken place between the mining
races. The German miners who came to England when Elizabeth was
queen, settled, some in Cumberland and some in Cornwall. Edward the
Black Prince is said to have taken many hundreds of the lead miners of the
northern counties to work the rich silver-lead mines of North Devon, and
the Cornish miners are allowed the merit of having introduced improved
machinery into the mines of Durham and Northumberland. Beyond the
similarities which may be traced to this interchange, there are others which
clearly belong to the business of mining, and which are probably as old as
the days when Job said, 'Surely there is a vein for the silver, and a place for
the gold, where they find it. Iron is taken out of the Earth, and brass is
molten out of the stone.'
"The psychological influences of subterranean toil form a strange but
interesting subject of study. These and the effects of that continued uncer-
tainty, as to the reward which labours of the severest kind are to receive, are
distinguishingly marked on every miner. In occult powers they are believers ;
and when, about a century since, the 'Divining Rod' (Dowsing Rod) was
introduced into Cornwall-as a means for finding mineral lodes, it was
eagerly seized upon, and, to the present day, several families are supposed
to possess remarkable powers as diviners, or, as they are commonly called,
'dowsers.' The most elementary laws of science are still a book sealed to
the large majority of miners, and while they are, of all men, themselves the
most theoretical, they always meet any attempt to explain phenomena upon
the evidences of inductive research, by pronouncing the explanation to be a
'theory,' which is of no value to a 'practical.'
The Royal School of Mines, which originated with Sir Henry de la
Beche, and which with the Museum of Practical Geology was inaugurated
on the 14th May, 1851, when the establishment was opened by his Royal
Highness the Prince Consort, was an effort to extend the advantages of
scientific instruction to all the miners of the United Kingdom. The words
of his Royal Highness, in reply to the address presented to him, deserve a
878
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
permanent record: "It is impossible to estimate too highly the advantages
to be derived from an institution like this, intended to direct the researches
of science, and to apply their results to the development of the immense
mineral riches granted by the bounty of Providence to our isles and their numerous
colonial dependencies."
The establishment of the Mining Record Office in 1840 has already been
mentioned. It is again referred to for the purpose of drawing attention to
the fact that in 1883 it was virtually abolished. It is true that the plans
of the abandoned metal mines collected have been removed to the Home
Office, to be placed and preserved with the plans and sections, which by
the "Mines Regulation Acts for 1872" are sent to that Department.
But all the Plans and Sections of such mines as are now in existence
remain at the Museum of Practical Geology, their future destination being
uncertain.
The following remarks by one of the best-educated and most practical
of our mining engineers are directly to the point, at the present time :—
"Among other causes which have retarded the progress of improvement
in subterranean operations, the speculative and uncertain nature of mining
is one of the principal.
"But mining, though certainly speculative, is not entirely the work of
chance. In it, as in all other business, he who classifies his accounts and
can at any time readily ascertain the exact sources of expenditure and
income-who derives experience from the constant accumulation of facts-
possesses very superior advantages over those who have no such data.
well-founded calculations of the one are, in the ordinary course of affairs, much
more likely to be attended with success, than the vague and unsatisfactory
speculations of the other.
The
"A reliance on chance instead of science-as the presiding genius of
mining adventure-must, sooner or later, affect its own existence, by
demonstrating that the instances of good fortune bear a very small propor-
tion of the numerous undertakings which end in disappointment, and create
a highly injurious prejudice against mining speculations.
"The prevailing idea of the uncertainty of mining adventure, and a con-
sequent disregard of method in conducting mines, are especially detrimental
to the interests of all concerned. The prospects of mining cannot indeed.
be reduced to certainty, but it is exceedingly desirable that all the details of
conducting it should be so. . . . . Whatever tends to increase a knowledge of
mining undoubtedly contributes to its permanent interests, and if the present
(1883) depression of the markets continue, if prices will not rise to meet
the present and increasing expenditure of mines, there is the greater necessity
for the adoption of every means to promote future economy and to prevent future
waste."
CHAPTER V.
GENERAL SUMMARY AND CONCLUSION.
WITH the concluding words of the last chapter this work might have
been reasonably brought to a close.
It appears, however, that some advantage may arise from an attempt to
summarise the facts which have deen collected, and to draw, what it is
hoped may prove, legitimate inferences from them. The records of the past
have been examined with care, for the purpose of ascertaining, if it were
possible to draw any conclusions from them, as to the extent to which the
exhaustion of the mineral wealth of the United Kingdom has been carried.
Out of this arises the following important considerations as to the future
prospects of the great national industry of Metalliferous Mining.
(a.) During the long period of which we have any account of the mining
operations carried forward in these islands, there has been an enormous
quantity of the useful metallic minerals obtained from the rocks in which
they were—in remote geological time—deposited.
(6.) Notwithstanding this, it has been proved that the exhaustion of our
mineral wealth is now going onward at a rapidly increasing rate.
(c.) The question arises, Is there a legitimate prospect of our being
enabled, for any prolonged period, to meet the demands of our Metallur-
gists and Manufacturers, by the supply of metalliferous minerals obtained
from the British mines, or must we be dependent on supplies from other
sources?
As an answer to these inquiries we venture to place before our readers
for their serious consideration the following remarks :—
Ist. The production of tin ore, from surface deposits, cannot much longer
be regarded as likely to be of much value. The tin ore to be obtained from
our mines is practically inexhaustible, but the additional supply can only
be procured by extending the depth of our mines, and consequently by
increasing the cost of working them. We have only one decided example
of the occurrence of tin at a considerable depth below the limits of the
copper-ore formation. This occurs in Dolcoath mine. The probability is,
that similar conditions to those which prevail in this grand old mine will be
found to continue in the adjoining mines on the north side of Carn Brea
Hill. Possibly also, looking at the undulations of the Granite, as shown in the
sections of the mines-so far as they have been worked in depth—a stratum
of the peculiar character of the deepest beds in Dolcoath may extend round
on the southern side of this hill, and give us a renewal of the stanniferous
deposits in all those mines.
2nd. The hypotheses which have been put forward in relation especially
880
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
to copper ore, certainly appear to show that although an uncertain quantity
of ore will probably be procurable over several areas, where productive
copper mines have been worked at depths beyond those at which the mines
have been abandoned, the quantity of copper ore to be obtained above
300 fathoms from the surface cannot be large. At the same time, it must
not be forgotten that the copper-bearing rocks may be found in many
places to dip at considerable angles, and produce deposits of copper ore of
considerable value in depth. The fact that there are lodes which were at first
worked for tin, which have at certain depths passed into copper lodes; and
again, after being worked for many years, changed into tin-producing veins,
supports the idea that below the zone now known as a stanniferous one,
an unexplored stratum bearing copper may be discovered. Until this
discovery is made, we must, to a considerable extent, be dependent upon
Colonial and Foreign mines for the metal required to meet the demands of
manufacture.
3rd. Lead, zinc, silver, &c., appear to follow the conditions which have
been shown to attend the occurrence of copper ore. The ores of these metals
may yet be found at greater depths than those at which they are now
worked. In general lead veins have become valueless in the lower strata.
Rodderup Fell vein in Alston Moor presents a remarkable exception.
Mr. Wallace has described this mineral deposit with great exactness. From
his description the following particulars are gathered. The strata in this
locality have a very rapid inclination, and the dip must be at nearly right
angles to the direction of the Great Sulphur vein, consequently on the line of
Rodderup Fell vein the strata rise in a direction from the east to the west.
The map given at page 462 will show that the strata on the south side is
much broken by intersecting veins and beds. These numerous small leads,
into which the veins are ramified, have been channels in which fluids have
been collected, and conveyed to Rodderup Fell vein. An abrupt change
from a higher to a lower level appears favourable to the deposition of lead
All the conditions favourable to the percolation and circulation of fluids
are found connected with Rodderup Fell vein, and so combined, that they
must have performed their functions in a peculiarly effective manner.
ore.
The formation of Limestone and Sandstone strata has been effected
under different conditions, and with dissimilar material. They agree, how-
ever, in being oceanic sedimentary deposits, and therefore the lead ore
found in the higher or the lower beds must have been held in solution, and
precipitated at the time when each stratum was forming. From this fact it
is rendered evident that the limits in depth of lead deposits are regulated by
the relations of the Limestone or Sandstone to the oceanic waters when
the ores were formed. It is not impossible that fissures containing lead ore
and silver may be found in beds much deeper than those which we are now
working. It may, however, with a considerable degree of safety, be pre-
dicted that the present supply of these metals will continue to require the
assistance of imported ores to satisfy the demands of art and industry, until
lower productive beds have been discovered.
4th. Iron ores exist in considerable quantities in several districts, and the
requirements of the Ironmaster may be, for some years, met without diffi-
CHAP. V.]
THE APPLICATIONS OF SCIENCE.
881
culty. There are, however, varieties of Foreign iron ore which will still be
of importance in the production of malleable iron and steel.
5th. The cost of raising ores by the subterranean labours of our Miners has
been for many years steadily increasing, and it naturally must continue to
increase with the extension of mine workings, unless an improved system
of mining be introduced. This applies with equal force to the mining
operations for all the metallic ores.
6th. Without great improvements in the principles of mining it will
not be possible to work, at a profit, many of our deeper and more extensive
mines.
The following matters especially require all the attention of active minds.
(a.) The breaking of ground. The jointed structure of rocks must be
carefully studied, that mechanical power may be used, and physical force
applied, to the greatest advantage.
(6.) Explosives should be experimented on with every precaution, and
those which give the largest result, with the smallest production of injurious
elements, should be adopted.
(c.) Boring machinery must be simplified as much as possible: the appli-
cation of the power employed to drive them should be the subject of very
close attention.
(d.) Ventilation—either natural or artificial-should be established on the
most approved principles, and carried out with the utmost economy. Pure
air should at any cost be secured in the deepest mines.
(e.) The raising and lowering of the miners and the drawing of the ores
are questions of the first importance. Upon the facilities afforded depends
the saving of time, and the preservation of health-each of these repre-
senting an equivalent in cost.
(f.) The drainage of mines demands the closest attention to the machinery
employed for pumping, and the engine-house of every mine should be always
kept in a condition of perfect cleanliness, and every bit of exposed metal
maintained in a high state of brightness. Power is always wasted where
neatness and purity do not prevail.
(g.) Every miner should have a personal interest in the mine in which he
labours. His health should be maintained in the highest state of efficiency :—
and in the event of accident or of disease—occasioned by the conditions
under which he labours-a provision should be made for securing the best
attention to his necessities.
(h.) Every possible improvement should be introduced for economising
the labours of the dressing-floors. If possible, every process should be
carried out by mechanical appliances-and all machines should be as nearly
automatic as engineering skill can render them.
(2.) The education of the future mine agents should be most carefully at-
tended to, especial regard being had to their knowledge of the applications
of science to the economical and useful arts. It does not appear desirable
that the mind of a working man should be burdened with the details of
scientific refinements, but of all the great laws, relating to the applications
of the physical forces, he should have a clear conception.
(k.) As altogether the wealth of the Nation is increased to the extent of
882
[BOOK IV.
FUTURE PROSPECTS OF BRITISH MINING.
£100,000,000 a year by mining operations, and its allied industries, it is of
the utmost importance that every possible improvement should be adopted
to support this important source of our National Wealth.
As no tradesman would have a chance of succeeding in his business,
without his well-kept day book and his carefully-adjusted ledger, it is quite
as important to train the miner in a careful system of registering the details
of production ("Mineral Statistics "), and of recording the progress of subter-
ranean operations by the most accurate surveys, and by preserving those
"Mining Records" in some appointed place, where they can be at all times
consulted not only without difficulty, but with convenience.
The matters to which especial attention must be solicited are of the
utmost importance if mining in the future is to be a profitable industry.
Beyond these, to enable the adventurers in our Home Mines to compete
satisfactorily in the metal markets with the proprietors of Colonial and
Foreign mines, and to realise a profit on the sale of their minerals, it is
absolutely necessary to study the strictest economy, and to establish—
beyond the risk of any failure-the highest principles of honesty in every
department, directly or indirectly, connected with British mining.
BRITISH MINING.
APPENDIX,
3 L
CONTENTS OF APPENDIX.
1. SPECIFIC GRAVITY OF METALS, PRECIOUS AND COMMON Ores.
2. TABLE SHOWING UNDERLIE AND PERPENDICULAR OF LODES, FOR SURVEYORS.
3. Annual Produce of the Tin of CornwALL FROM 1750 TO 1817.
4.
""
""
""
""
1818
,, 1837.
5. GENERAL STATEMENT OF TIN TRADE OF CORNWALL FROM 1750 TO 1799.
6. ANNUAL PRODUCE OF THE TIN OF CORNWALL FROM 1848 TO 1882.
7. Average PRICE PER TON OF TIN ORE AND TIN SINCE 1854.
8. TIN SHIPPED FROM CORNWALL FOR CHINA, BY THE EAST INDIA COMPANY.
9. QUANTITY OF TIN EXPORTED FROM 1788 TO 1791, SHOWING COUNTRIES.
10. TIN SUPPLIED TO EAST INDIA COMPANY BY CORNWALL UNDER STOCKIng System.
II. PRODUCTION OF COPPER ORE IN CORNWALL FROM 1726 TO 1775-
12. ANNUAL PRODUCE OF COPPER IN CORNWALL FROM 1727 TO 1771.
13. CORNISH COPPER ORES SOLD AT TICKETINGS FROM 1772 TO 1799.
14. ANNUAL SALES OF COPPER ORE AT CORNISH TICKETINGS FROM 1800 TO 1881.
15. COPPER SALES (BRITISH, COLONIAL AND FOREIGN) AT SWANSEA FROM 1804 TO 1863.
16. ANNUAL COPPER SALES AT SWANSEA FROM 1861 TO 1881.
17. TRANSACTIONS AT CONSOLIDATED MINES FROM 1819 TO 1836.
18. PRIVATE CONTRACT PURCHASES FROM 1832 TO 1862.
19. AVERAGE PRICES OF COPPER ORE AND COPPER SINCE 1855.
20. TABLE OF Cost at FOWEY CONSOLS MINE IN 1837.
21. COPPER PRODUCE, MONA MINE, ANGLESEA, FROM 1855 TO 1882.
22.
""
PARYS MOUNTAIN MINE, ANGLESEA, FROM 1855 TO 1882.
23. FINE COPPER FROM MONA AND PARYS MOUNTAIN MINES FROM 1820 TO 1835.
24. LEAD ORE, LEAD, AND SILVER, OBTAINED FROM 1848 TO 1871.
25.
26.
""
>>
""
""
""
CORNWALL FROM 1845 TO 1882.
DURHAM AND NORTHUMBERLAND SINCE 1845.
27. GREENWICH HOSPITAL DUTY LEAD ORE FROM 1768 TO 1881.
28. LEAD ORE, LEAD, AND SILVER FROM ALLENDALE AND WEARDALE FROM 1845 TO 1881.
29.
>>
""
30.
31.
""
32.
""
""
""
""
CARDIGANSHIRE FROM 1845 TO 1882.
THE ISLE OF MAN
""
""
SCOTLAND
""
""
IRELAND
""
""
""
33. PRICES OF Lead at GrASSINGTON FROM 1780 TO 1843.
34.
""
ENGLISH LEAD-PER FODDER-FROM 1783 TO 1828.
35. ZINC ORE RAISED IN UNITED KINGDOM FROM 1856 TO 1882.
36. PRICES OF ZINC ORE AND METALLIC ZINC FROM 1858 TO 1881.
37. IMPORTS AND EXPORTS OF ZINC FROM 1823 TO 1858.
38. MANGANESE, PRODUCE OF, FROM 1872 TO 1881.
GLOSSARY.
APPENDIX.
TABLE No. I.
SPECIFIC GRAVITY OF METALS, PRECIOUS AND COMMON ORES.
METALS.
GOLD.
Sp. Grav.
19.25
Sp. Grav.
MERCURY 13.26
•
LEAD.
SILVER
11.35
10'47
COPPER
IRON
Sp. Grav.
8.89
Sp. Grav.
7.78
TIN
ZINC
7.30
7.00
ORES OF PRECIOUS METALS.
GOLD-Iron Pyrites (mundic), associated with gold and sometimes silver
Magnetic Pyrites (pyrrhotine)
Arsenical Pyrites (mispickel)
Copper Pyrites (chalcopyrite)
SILVER-Horn Silver (kerate)
Argentite (silver glance or sulphide of silver)
Stephanite (brittle sulphide of silver)
Pyrargyrite (dark red silver ore)
Proustite (light red silver ore)
•
MERCURY-Cinnabar (sulphide of mercury)
Cassiterite (tinstone)
TIN.
COMMON ORES.
Hardness. Sp. Grav.
6.0 to 7.0.6.8 to 7.0
Tin Pyrites (bell-metal ore). 3'0,, 4·0 · 4·6,, 5'1
Chessylite (blue carbonate of
COPPER.
Cuprite (ruby or red copper ore) 3'5,, 4·6 .
Melaconite (black oxide of cop.) 1.0 2.0.
Malachite (green carbonate of
6.0
5.2
copper)
3'5,, 4'0.
4.0
•
3'5,, 4'0.
3.8
2°5,, 3°0 .
5.6
3.0
5.0
3.5 to 4.0.
4.2
3.0
4.2
2.2
copper or azurite).
Tetrahedrite (grey copper ore)
Erubesite (purple or horseflesh
ore)
Chalcopyrite (yellow copper ore
-copper pyrites)
Olivenite (arseniate of copper)
Chrysocolla (silicate of copper) 2.0 to 3.0.
ANTIMONY.
2 2 2
Antimonite (grey antimony ore) 2.0 4.5 to 4.7
Bournanite (Endillionite) 2.5 to 30.5'7" 5'9
Jamesonite (sulphide of lead
·
Hardness.
6 to 6'5
3'5,, 4'5
6.0
•
Sp. Gravity.
4.8 to 5.2
•
4'4,, 47
6.0 6.4
4.I,, 4'3
5.5">
5.6
7.2,, 7°3
5.2,, 6.3
•
""
5.5 ››
""
•
3°5,, 4'0
•
I'O 1.5
2.0
•
2.5
•
•
•
2.0 2.5
•
·
2.0 2.5
•
5°7,, 5'9
•
2'0 2.5
•
5°4,, 5.6
8.0
8.2
""
""
""
. 2.0 2.5
MANGANESE.
Psilomelane (compact manga-
nese ore).
Pyrolusite (red oxide of man-
ganese)
•
Manganite (grey oxide of do.).
•
Hardness.
Sp.Grav.
50 to 60. 3.7 to 4.3
2.0,, 2.5.4.7
2'5 · 4*7,, 5'0
3'5", 40. 42,, 4'4
Wad (earthy manganese) O'O,, 3'0. 2'0,, 3·7
Diallogite (carbonate of man-
ganese)
•
Rhodonite (bi-silicate of man-
ganese)
LEAD.
Galena (sulphide of lead)
Cerussite (white lead ore)
Anglesite (sulphate of lead)
•
•
·
Pyromorphite (phosphate of
lead)
3'5,, 4*5 · 3'3,, 3'6
5'5,, 7'0. 3'5,, 3'7
2.0
""
2.5.7.2,, 7.6
6.5
30,, 3'5
27,, 30.6.0 to 6.3
3'5,, 4'0. 7.0
Mimetene (arseniate of lead). 3'5,, 40.70 to 7.25
ZINC.
and antimony)
•
2.0,, 2.5.
5.5
Calamine (carbonate of zinc) .
Smithsonite (silicious oxide of
5'0
• 45
BISMUTH,
zinc)
5.0
3.5
Bismuthine (sulphide of bis-
muth)
Bismuth Ochre (oxide of bis-
muth)
2'0,, 2·5. 6·4 to 6·6
4.3
Tetradymite (telluric bismuth). 15 to 2.0. 7.2 to 4'3
Blende (black-jack, sulphide of
zinc)
•
3.5 to 4.0.3.9 to 4.2
TUNGSTEN.
Wolfram (tungstate of iron). 5'0,, 5˚5 · 7°2,, 7′5
3 L 2
886
APPENDIX.
IRON.
Magnetite (magnetic iron ore)
Hæmatite (red iron ore, spe-
cular iron)
Limonite (brown hæmatite)
Chalybite (spathose iron ore).
Sulphate of Baryta
Carbonate of ditto
Carbonate of Iron
Granite
Gneiss
Mica Slate
Syenite
Hornblende
•
•
Greenstone Trap
Basalt
Porphyry
•
Hardness. Sp. Grav.
6.0 to 6.5.4.8 to 5.1
Leucopyrite (arsenical pyritės) 5·5,, 6·0 .・ 6′0
COMMON ORES (Continued).
Hardness. Sp. Grav.
Pyrites (yellow mundic)
6.0.5.0 to 5.2
6.0
5.2
5.0 to 5.5.3.6 to 4.0
3.8
4.0
•
NICKEL.
Chloanthite (white nickel-
gray cobalt)
Nickelkies (copper nickel)
GANGUEIFEROUS MINERALS.
Hardness.
Sp. Grav.
2.5 to 3.5 43 to 4.8
•
3'0,, 3.7
· 3'0,, 4'5
•
·
4.3
3.7 to 3.8
Fluor-spar
Quartz, or Silica
Carbonate of Lime.
in in
55
5.5
5.5
Hardness.
4.0
7.0
•
2.5 to 3.5
•
VEINIFEROUS. (FRAGMENTS or Brescia of adjacent Rocks.)
Sp. Grav.
•
2.4 to 2.7
•
•
2.6
24,, 2.7
,, 2'9
2.7,, 3'0
Talcose Slate
Clay-Slate (Killas)
Serpentine
6.5
.7.5 to 7.7
Sp. Grav.
3.0 to 3.3
2.6 2.M
2.5,, 3·8
Sp. Grav.
2.6 to 2.8
2.8
·
2.5",
Chloritic Slate
•
2.7,, 2.8
•
•
2.5,, 2.7
•
30,, 3'1
•
2.7,, 2'9
Limestone and Dolomite
Sandstone
•
2.5,, 2'9
I'9,, 27
2.6
•
29 3.I
Shale, or Schiefer
2.8
•
•
2.3, 2.7
TABLE No. 2.
SHOWING THE UNDERLIE AND PERPENDICULAR OF LODES, IN FEET AND INCHES, TO EVERY
DEGREE OF THE QUADRANT IN SIX FEET. (Page 662.)
BASE.
PERP.
BASE.
PERP.
Degrees.
Feet.
Inches.
Inches.
5 II
5 II:
5 II
5
9
5 II
ΙΟ
II
5 107
5 108
12
5 10
13
-
14
5
15
5
16
5
17
5
18
5
19
20
21
22
5
•∞∞∞776
012345678
6 O
I
6
ыыыыыыыыыыыыыыыыыыыы
5 II
100
O O
5 11
5 II
012356
89
88
87
86
85
தன்ன
90
2 2 2 2 2 2
23
5 61
2 4
24
5 6
2
25
26
27
28
5 3/1/
OOKROO/HIP/WP|-
2
2
2
29/1
Horka/01-400
84
29
5 3
2 II
83
30
Ο ΙΟ
82
31
mkomt
3
3
0
I
O II
81
32
5 I
3
23
I
WPY
80
33
5
3 34
I
I
I
I
I
I
13456∞
79
78
77
colo-ka
76
75
33333
+567O
34
3 4
cerche age Degrees.
9876
64
58
56
35
4 II
3 5/1/2
55
36
4 101
37
38
8
74
39
I 9
73
40
4
I 101
72
41
4
I II
71
42
4
2 2 2
O
70
43
4
I
69
44
4 4
2 3
68
45
4 3
HAKE+
2∞∞76 5443
BLETIT
3 61
54
3 74
53
3
3 99
3 10/1/
3 11
II
4 0
4 I
4 2
4 3
Inches.
Degrees.
Inches.
Degrees. Acerc
52
51
50
49
48
47
46
45
PERP.
To
BASE.
PERP.
BASE.
EXAMPLE. TO Horizontal Quadrant, angle down, 25°; length 9 fms. 3 ft.
Opposite 25° in this Table is 5 ft. 51 in. x 9 fm. 3 ft.=54 73. For Perpendicular,
2 ft. 6 in. × 9 fm. 3 ft.-24 0§.
This Table is calculated for the Quadrant taking its angle from the horizon.
N.B. When the angle exceeds 45°, read from the foot of the Table, and take
the Base and Perpendicular as marked there.
APPENDIX.
TABLE No. 3.
887
AN ACCOUNT OF THE ANNUAL PRODUCE OF THE TIN MINES OF CORNWALL FROM THE
YEARS 1750 TO 1817.
Year.
Blocks.
Tons.
Average Price
per Cwt.
Year.
Blocks.
Tons.
Average Price
per Cwt.
No.
£ s. d.
No.
1750
18,698
2,876
3 4 10/
1784
17,456
2,685
£ s. d.
3 10
6
1751
14,776
2,273
1752
16,574
2,550
3 7
1753
16,358
2,516
38 0
кно
I
1785
18,753
2,885
3 12 O
1786
22,096
3,399
3 12
1787
20,824
3,204
3 12 O
1754
17,708
2,724
3 7 10
1788
21,790
3,352
3 6 6
1755
17,924
2,757
37 0
1789
22,132
1756
3,405
3 2 6
18,033
2,774
3 2 7/
1790
20,753
1757
17,881
3,193
3 12 6
2,752
2 19 3
1791
22,561
1758
3,470
3 19 0
17,681
2,720
2 16 3
1792
24,763
3,809
4 12
6
1759
17,140
2,637
2 16 0
1793
• 20,805
3,202
4 18
1760
17,662
2,717
2 16 0
1794
21,793
3,351
4 15
6
1761
15,571
2,395
2 19 101
1795
22,353
3,440
4 13
1762
16,801
2,584
349
1796
19,902
3,061
4 16 6
1763
17,786
2,736
3 8 10/1/2
1797
21,063
3,240
4 17
1764
16,997
2,618
39
1798
18,332
2,820
4 14 O
1765
17,923
2,757
39
1799
18,603
2,862
4 17
1766
19,861
3,055
39
1800
16,397
2,522
5 I
1767
18,529
2,850
39
1801
14,552
2,328
5 5
1768
17,334
2,667
39
1802
16,420
2,627
5
1769
18,838
2,898
39
1803
18,212
2,914
5 9
1770
19,355
2,977
3 6 6
1804
18,716
2,993
5 9
1771
18,349
2,823
3 5
1805
17,139
2,742
5 12
6
1772
20,531
3,159
3 3
1806
17,846
2,855
6 o 6
1773
18,540
2,852
2 14
1807
15,168
2,426
5 17
6
1774
15,975
2,458
2 12
6
1808
14,589
2,330
14
1775
17,024
2,619
3.0
1809
15,690
2,508
6 2
1776
17,240
2,652
2 19 9
1810
12,528
2,006
7 17
O
1777
18,010
2,770
2 19 6
1811
14,675
2,384
1778
16,302
2,515
0 6
1812
14,606
2,373
7 I 6
68
O
1779
17,411
2,678
O
1813
14,306
2,324
6 14
O
1780
19,052
2,926
I
1814
16,069
2,611
7 16 6
1781
16,969
2,610
34 3
1815
18, 101
2,94I
7 0 6
1782
16,548
2,546
3 10
O
1816
20,608
3,348
5 14 6
1783
16,705
2,570
3 10 о
1817
25,379
4,120
4 13 6
TABLE No. 4.
AN ACCOUNT OF THE PRODUCE OF THE TIN MINES OF CORNWALL AND DEVON, DISTINGUISHING
GRAIN AND COMMON TIN, AND PRICES IN THE MARKET FROM 1818 TO 1837.
Blocks.
Year.
Total Blocks.
Tons.
Price
of Refined
Tin
Price
of Common
Common.
Grain.
in Wales.
No.
No.
No.
S. d.
Tin in
Cornwall.
S. d.
1818
19,468
3,755
23,243
4,066
88
O
84 9
1819
17,091
1,856
18,947
3,315
78 6
75 3
1820
15,338
1,746
17,084
2,990
76 9
73 3
1821
17,022
2,251
19,273
3,373
81 O
75
8
1822
16,574
2,157
18,731
3,278
100
O
95
1823
21,662
2,415
24,077
4,213
105 3
94 9
1824
25,837
2,765
28,602
5,005
93 3
88 O
1825
23,066
1,836
24,902
4,358
94 6
91 4
1826
24,787
1,512
26,299
4,603
82 3
77
1827
29,965
1,779
31,744
5,555
83
3
76 O
1828
26,386
1,792
28,178
4,931
81
9
73
1829
23,929
1,408
25,337
4,434
80 3
74
O
1830
23,593
1,799
25,392
4,444
1831
23,194
1,374
24,568
4,300
1832
23,35I
1,351
24,702
4,323
1833
21,994
1,237
23,231
4,065
1834
21,397
1,395
22,792
3,989
78 778
78
83
78
78
88
∞ 3∞ ∞ ∞
73 9
73 6
72 9
72 9
6
78 0
1835
22,637
1,523
24, 160
4,228
99
91
6
1836
21,477
1,692
23,169
4,054
114 3
109 6
1837
25,891
1,482
27,373
4,790
93 3
88 O
NOTE.-A block of tin weighs 3 cwts. 2 qrs.
888
APPENDIX.
TABLE No. 5.
GENERAL STATEMENT OF THE TIN TRADE OF CORNWALL
FROM 1750 TO 1799 INCLUSIVE.
Quantity
Raised, Grain and
Years of Peace
and War.
Common.
Exported to Europe,
Africa,
and America.
Blocks.
6 to
Tons.
Blocks.
Tons.
I
Average Price
Tin, exclusive
of Prince's
Duty, &c.
per Cwt.com.
Peace. 1750
18,698
2,876
1751
14,776 2,273
1752
16,574 2,550
1753
16,358
2,516
1754
17,708
2,724
1755
17,924
2,757
War. 1756
18,033
2,774
1757
17,887 2,752
1758
17,681 2,720
1759
17,140 2,637
1760
17,662 2,717
1761
15,571
2,395
1762
16,801
2,584
Peace. 1763
17,786
2,736
1764
16,997 2,618
1765
17,923
2,757
1766
19,861
3,055
1767
18,529
2,850
1768
17,334 2,667
1769 18,838 2,898
1770
19,355
2,977
1771
18,349 2,823
1772
20,531 3,159
War. 1773
18,540 2,852
1774
15,975 2,458
1775
17,024 2,619
1776
For 33 years no Account of the Exports obtained from the
Custom
House.
3
3
£ s. d.
3 4 10
3 5 I
нно
I
3
7 10
3 7 0
3 2 7
2 19 3
2 16 3
2 16 O
2 16 O
2 19 10
349
8 10
3 8
3 9
3 9
3
3 9
3 9
3
36
3 5 O
3 3 3
2 14 O
212 6
300
2 19 6
2 19 6
17,240 2,652
1777 18,010 2,770
1778 16,302 2,515
1779
17,411 2,678
1780 19,022 2,926
1781 16,969 2,610
Peace. 1782 16,548 2,546
1783 16,705 2,570 10,988
1784 17,456 2,685 10,169
1785 18,753 2,885 13,022
1786 22,096 3,399 15,265
1787 20,824 3,204 14,498
1788 21,790
Peace. 1789 22,132
3
O
300
3
I 3
34 3
3 10
1,690
3 10
1,564 3 10
2,003 3 12 O
6
2,348
3 12
O
2,233
3 12 O
3,352 14,992
2,306
366
3,405 13,760
1790 20,753
1791 22,561
3,193 10,569
2,117 3 2
1,626
3 5
War. 1792 24,763 3,809
3,470
12,538
1,929
3 10
O
II, 141
1793 20,805
1794 21,793 3,351 8,417
1795 22,353 3,440 10,246
1796 19,902 3,061 7,871
1797 21,063 3,240 5,817
1798
18,332 2,820 9,824
1799 18,603 2,862 7,644
3,202
7,III
1,714 4 I
1,095
3 15 7
I,295
3.12
1,576 3 IO 8.
1,212 3 15 5
895 3 10
1,511 3 12
1,176 430
87580 INLO∞ O
6
8
APPENDIX.
889
TABLE No. 6.
AN ACCOUNT OF THE TIN ORE AND METALLIC TIN OBTAINED FROM THE MINES OF CORNWALL
AND DEVON IN EACH YEAR SINCE 1848.
Tin Ores.
Year.
(Black Tin.)
Metallic Tin.
(White Tin.)
Year.
Tin Ores.
(Black Tin.) '
Metallic Tin.
(White Tin.)
Tons.
Tons.
Tons.
Tons.
1848
10,176
1866
15,080
9,990
1849
10,719
1867
13,649
8,700
1850
10,383
1868
13,953
9,300
1851
9,455
1869
14,725
9,760
1852
9,672
1870
15,234
10,200
1853
8,866
5,763
1871
16,272
10,900
1854
8,747
5,947
1872
14,266
9,560
1855
8,947
6,000
1873
14,885
9,972
1856
9,350
6,177
1874
14,039
9,942
1857
9,783
6,582
1875
13,995
9,614
1858
10,618
6,920
1876
13,688
8,500
1859
10,670
7,100
1877
14,142
9,500
1860
10,462
6,695
1878
15,045
10,106
1861
I1,640
7,450
1879
14,665
9,532
1862
14,127
8,476
1880
13,737
8,918
1863
15,157
10,006
1881
12,900
8,600
1864
15,211
10,108
1882
14,044
9,157
1865
15,686
10,039
TABLE No. 7.
AVERAGE PRICE (PER TON) of Tin ORE AND METALLIC TIN IN EACH YEAR SINCE 1854.
Year,
Tin Ore.
Metallic Tin.
Year.
Tin Ore.
Metallic Tin.
s. d.
1854
64 O
£
114 O
S. d.
£ S. d.
£
S.
1868
55 4
98 0
of
d.
1855
68
119
1869
69 16 O
123 2
1856
о
133 0
1870
75 3
1857
76 O
136 O
1871
78 12
6
127 8 6
137 10
1858
63 4
119 2
1859
74 15
130 18 3
1860
71 II 6
136 3
1861
62 6
8
122 5
1862
59 14 O
116 0
23IO O
1872
87 7
152 15
1873
78 I о
133 7
1874
56 3
108 8
1875
52 11
6
90 2 O
1863
63 12
O
117 O
1876
1877
43 18
O
79 10
2
40 10
O
73 3 6
1864
60 17 6
107 I
1878
35 5
1865
55 6
O
96 15 0
1879
40 O
65 12 3
72 6
1866
48 10
9
88 12
6
1880
49 O
91 5
1867
50 18
O
91 17 3
1881
54 O
97 9 3
890
APPENDIX.
TABLE No. 8.
AN ACCOUNT OF TIN SHIPPED FROM CORNWALL BY THE EAST INDIA COMPANY FOR CHINA.
1762. 401 boxes of Cornish grain tin
187
common tin
1763. 141
1766. 40
1768. 200
Cornish grain tin
common tin
""
""
•
Cwts.
1,920
qrs. lbs.
3 27
599 I 12
712 2 9
206
I 24
1,014
3 4
4,454
0 20
Tons.
1789. In blocks, ingots, and caps, shipped by the Company .
Price £68 to £69 10s. per ton.
In private trade
Price from £66 to £69 per ton.
1790. Shipped by the Honourable East India Company in ingots for China .
Shipped for Madras, Bengal, and Bombay, by way of trial
50
38
775
25
TABLE No. 9.
It appears that since the opening of the Tin Trade from the County of Cornwall to China, in 1789, the
quantity of Tin raised in the County from that period to 1816 inclusive, 28 years, is 78,242 tons; deducting
Prince's Duty, Shipping Charges, &c., has produced a sum to the Tin Interest of the County, equal to the
quantity raised the preceding 39 years, say, 107,536 tons. Further, that the average price of Common
Tin sold to the East India Company for 28 years, deducting all the charges whatever, estimated at
£9 6s. 2d. per ton, is equal to the average price of all the Common Tin raised in Cornwall for 39 years
previous to the commencement of the trade to China.
GEORGE UNWIN.
AN ACCOUNT OF THE QUANTITY OF TIN EXPORTED FROM GREAT BRITAIN IN THE FOLLOWING
YEARS, DISTINGUISHING THE COUNTRIES TO WHICH IT HAS BEEN EXPORTED.
1788.
1789.
1790.
5th Jan. to
July 5th, 1791.
1791.
COUNTRIES.
Cwts. gr. lb.
lb. Cwts. gr. lb. Cwts. qr. lb.
Cwts.
qr.
lb.
Cwt. qr. lb.
DENMARK and NORWAY
Russia
Sweden
Poland
•
•
372 I 15
8,028 1 16
986 3 20
324 2 7
906
6,687
I O 472 O
3 21| 5,051
2
900
0 7
179 I II
3
I 21
Prussia
Germany
I
•
•
•
401
2,719 O 04,972
O
806
2 22
34 3 24
356 3
3 1| 2,996 I
Holland.
Austrian Flanders
•
French Flanders and France
Portugal.
Spain
Gibraltar
9 2 14
Turkey
•
Italy and Venice
Ireland
Guernsey and Jersey
Africa
00 O
5,965 0 10 3,461 I 65,293
2,368 0 10
739 I 9
0 2
5,217 0 25 7,817
1,662 I 12 607
13,339 2 10 5,426 I 16 2,749 3 20
1,019 O 0 0 1,600 I 19 629 I O
2,555 0 18 3,327 I o 1,373
32%
I 26
50 0
2 17
4,396 0 14
979 O 9
I O 581 0
681 475 H
257 2
03,670 3 14
686 2 6 2,504 0 13
о
313 0 6 1,058 0
38 2 24
258 2
2
39
0 17
744
I
3
2
5 1,315
8
2,129
3 27
•
•
77 O O
West Indies
•
155
I
8
•
States of America
British Continental Colonies
55
I 18
139 2 23
4,232 3 19
731 3 9
O O
62 O O
118 0 17
75 3 16
616 0 O
2
3 19 7,078 o 8 2,800 0 18
I 418 3 5 793
2 13
2,342 O 22 6,434 2 13
316 I O 853 0 23
1,800 0 25 3,164 2
76 0 о 76 0 0
2,879 3 64,515 0 16
2,074 3 10 6,434 I I 3
551 0.12 936 3 18
O O O
о
4,672
o 9
O
O
O
129 3 8
72 I 13
109 3 27
O
40
O
O
48 3 16
39
2 14
345
2 17
205
2
7
376 O 7
O O O
46,136 I 1942,344 I 25 32,534 O O 7 16,421 I 23 38,597
I 22 13,754
INDIA and CHINA
300 0 0 1,960 2 22 25,674
46,436 I 19 44,305
I 1944,305 0 19 58,208
2 23 13,754
I 17
I 22
3 2 30,175 3 17 52,711 3 II
We exported in the Year 1783
""
>>
""
""
1784
1785
""
1786
29
1787
not exceed 1,000 Tons.
The Annual Quantity of Tin raised in Cornwall, about 3,400 Tons,
Cwts. qrs. lbs.
33,814 O
31,288 0
40,062 0
46,965 0
44,612 0 0
and the Home Consumption did
APPENDIX.
TABLE No. 10.
891
TIN SUPPLIED TO EAST INDIA COMPANY BY CORNWALL UNDER THE STOCKING SYSTEM:-
From
To
Tin.
Tons
cwts.
qrs.
lbs.
October, 1793
April,
1794
1,232
16
2
17
December, 1794
May,
1795
I,202
5
O
26
January, 1796
June,
1796
1,202
12
December, 1796
April,
1797
1,062
November, 1797
March,
1798
I,229
16
240
I
14
O
9
I
December, 1798
November, 1799
October, 1800
November, 1801
September, 1802
November, 1803
November, 1804
February, 1806
January, 1807
May, 1799
802
17
I
April, 1800
687
IO
February, 1801
701
9
March,
1802
302
I
March, 1803
394
II
I
April,
1804
595
14
March,
1805
851
19
I
March, 1806
375
13
March, 1807
642
16
I
221
132 3E3E21
15
24
7
23
27
16
I
21
December, 1807
December, 1808
January, 1810
October, 1811
April,
1808
692
16
May, 1809
841
15
March,
1811
379
March, 1812
449
652O
O
I
27
23
9
October, 1812
February, 1813
856
I
November, 1813
February, 1814
619
16
December, 1814
February, 1815
472
7
February, 1816
349
14
October, 1816
March, 1817
406
7
1233T O
I
5
23
16
I
21
+36 +1
4
4
March, 1821
48
15
2
23
January,
1822
126
18
February, 1822
150
O
June,
1822
28
18
013
5
I
14
3
7
TABLE No. II.
PRODUCTION OF COPPER ORE IN CORNWALL FROM 1726 TO 1775. (Pryce.)
Tons.
£ S. d.
1726 inclusive, to end of 1735 was
64,800 at average price of 7 15 10 per ton.
1736
1746
1756
1766
""
""
1745
1755
""
75,520
98,790
786
""
""
""
""
""
1765 169,690
""
7 8 O
7 6
""
0
""
1775 264,273
""
6 14
6
""
£
£
From 1726 to 1735 Yearly value 47,350
Total of years =
473,500
""
1736
""
1745
""
1746
,, 1755
1756 1765
1766
", 1775
56,010
""
565,616
73,145
""
731,457
124,304
"
= 1,243,045
177,833
= 1,788,337
TABLE No. 12.
AN ACCOUNT OF THE ANNUAL PRODUCE OF COPPER ORE from CORNWALL FROM 1727 TO 1771.
Year.
Copper Ore.
Year.
Copper Ore.
Year.
Copper Ore.
Tons.
Tons.
Tons.
1727
6,700
1742
6,050
1757
17,000
1728
6,800
1743
7,040
1758
15,000
1729
6,870
1744
7,230
1759
16,700
1730
6,900
1745
6,700
1760
15,780
1731
7,000
1746
7,000
1761
17,004
1732
7,290
1747
4,900
1762
16,054
1733
7,000
1748
6,000
1763
17,898
1734
6,000
1749
7,200
1764
21,489
1735
5,240
1750
9,400
1765
16,774
1736
8,000
1751
I 1,000
1766
21,251
1737
9,000
1752
12,050
1767
18,502
1738
10,000
1753
13,000
1768
23,671
1739
I 1,000
1754
14,000
1769
26,655
1740
5,000
1755
14,240
1770
30,776
1741
5,500
1756
16,000
1771
27,896
892
APPENDIX.
TABLE No. 13.
THE ANNUAL PRODUCE OF THE COPPER MINES OF CORNWALL SOLD AT TICKETINGS, GIVING
THE ORE, THE MONEY VALUE, and STANDARD, FROM 1772 TO 1799.
Year.
Copper
Ore.
Copper.
Amount.
Money Value.
Standard Year.
Copper
Ore.
Amount.
Copper. Money Value.
Standard
Tons.
Tons.
£
£
Tons.
Tons.
1772
27,965 3,556
189,505
81
1786
39,895
4,787
£
237,237
£
75
1773
27,663 3,320
148,43I 70
1787
38,047
190,738 67
1774
30,254 3,630
162,000
68
1788
31,541
150,303
57
1775
29,966 3,596
192,000
78
1789
33,281
184,308
63
1776
29,433 3,532
191,590
79
1790
1777
28,216 3,386
177,000
77
1791
1778
Not obtainable.
24,706
2,965
140,536
72
1792
1779
31,115
3,734
180,906
73
1793
1780 24,433
2,932
171,231
83
1794
42,816
320,875 88
1781
28,749 3,450
178,789
77
1795
43,589
326,189
87
1782
28,122
3,375
152,434
70
1796
43,313
356,564 93
1783
35,799
4,296
219,937
76
1797
47,909
5,210
377,838 96
1784 36,601
4,392
209,132
72
1798
51,358
5,600
422,633
1785 36,959
4,434 205,451
71
1799
51,273
4,923
469,664 121
TABLE No. 14.
THE ANNUAL SALES OF COPPER ORES AT TICKETINGS SINCE 1800, GIVING THE QUANTITY OF
COPPER, THE PERCENTAGE PRODUCED, AND STANDARD.
Year.
Copper Ore. Copper. Produce.
Standard.
Year.
Copper Ore. Copper. Produce.
Standard.
¡
Tons.
Tons.
£
1801
1800 55,981
56,611
5,187
5,267
1805
1814 74,322
1802 53,937 5,228
1803 60,566 5,615
1804 64,637
78,452 6,234
1806 79,269 6,863
1807
71,694 6,716
1808 67,867 6,795
1809 76,245 6,821
1810 66,088 5,683
1811 66,768 6,141
71,547 6,720
1813 74,047 6,918
1812
ΙΟ
5,375
6669∞ 7∞ a
91
s. d.
133 3 6
Tons.
Tons.
£ s. d.
1843
153,668
10,926
71% 110
216
O
117 5 о
1844
152,667
11,246
7%
110 18
1845
162,557
12,883
7*
122
O
1846
150,431
11,850
136 5
1847
148,674
11,966
169 16
1848 155,616 12,869
16
109 0
103 10 O
721% 106 8 O
8-16 103 12
8/12
138 5
1849
144,983
12,052
8116
120 о
1850
150,890
100 17
1851
11,824
154,299 12,199
8/17-
143 12
1852 152,802
11,706
83
132 5
I20 IO
III O
1853 180,095
11,839
1854
180,687
II,779
1855
188,969
12,242
115 7
1856 209,305 13,274
6,369
130 12
1857 198,697
13,088
1815 78,483
6,526
117 16 6
1858
183,292 11,764
1816 77,334 6,697
98 13
1859
183,944 11,888
1817 76,701
6,498
1822 104,523
1823 95,750
1818 86,174 6,849
1819 88,736 6,804
1820 91,473 7,508
1821 98,426
8,515
9, 140
7,928
1824 99,700 7,824
1825 107,454
1826 117,308 9,026
1827 126,710
1828 130,366
1829 124,502
10,311
1830 133,904 10,748
1831 144,402 12,044
1832 137,357
1833 138,300 I1,191
877∞∞∞∞
108 10
1860
180,448 11,769
65
134 15
127 10
113 15
1861
180,778 11,486
1862 183,313
11,566
103 O
104 O
109 18
1863
169,971
10,896
63
1864
165,601
10,273
6/1/16
1865 159,409
9,750
6ㅎ
​416
31
73 103 19
7416
ΙΟΙ O O
106 12
136 16
140 2 O
141 10
140 O
616 139
139 6
135 I
681 133
133 6
133 8
62
416
16
O
130 15 0
123 16 O
1195 O
127 19
O
122 12 O
O
97 7
O
92 II
O
7
8,226
9,921
9,656
8
II,947
1834
143,296
I1,225
1835
150,617
12,270
1836
140,981
11,647
-1001000 m3ko 1100/COCH
•~~~ 77∞∞∞∞∞∞
IIO O
1866 138,141
8,799
ooks
109 7 O
114 O
123 3
1867 119,766
8,027
106 I
112 7
109 14
106 5
ICO
1868 117,262 7,667
1869 94,606
6,544
1870 81,278 5,606
1871 71,118
4,682
1872 65,386 4,129
68 110 9 O
6/1/1/0
107 10
671 101 6 O
O
6/1/ 98 I
61 102 10
611 119 18 O
O
100 O
III O
1873 55,095
3,782
6%
114 о
1874 49,175
3,542
106 II
115 12
1875 51,122
1876 57,985 3,841
3,521
67/F
1_1
102 II
16103 O
6금 ​113 7
O
1837
140,753 10,823
119 о
1838
145,688
I1,527
109 O
1877 53,785
1878 47,591
3,714
107 9
97 6
3,390
7ㅎ
​88 4 0
1839
159,551 12,450
ΠΙΟ о
1840 147,266 11,037
73
108 10
1841
147,846 9,987
119
O
1842
154,180
9,896
71% 120
1879
1880
1881
42,094
40,311
2,889 67
2,754
40,584
2,681
7000/442000
623216
89 5 0
95 O
94 8 0
APPENDIX.
TABLE NO. 15.
Copper Ore Sales at SwansEA TICKETINGS from British, Colonial, and FOREIGN,
FROM 1804 TO 1863.
British Mines.
Year.
Colonial
and
Foreign
Total Sales,
British
and Foreign.
English.
Welsh.
Irish.
TOTAL.
Mines.
Tons.
Tons.
Tons.
Tons.
Tons.
Tons.
1804
52
52
1806
41
62
103
1807
68
810
878
1808
312
1,391
1,703
1809
240
530
770
1810
400
603
1,003
1811
88
68
156
1812
622
120
742
1813
442
213
655
1814
321
429
750
1815
77
1,079
700
1,856
1816
35
600
673
1,308
1817
422
9
431
1818
317
247
349
913
1819
1,796
90
1,531
3,417
1820
1,408
124
2,200
3,732
1821
957
191
2,040
3,188
1822
521
412
1,923
2,856
1823
633
564
3,673
4,870
1824
436
358
4,47I
5,265
1825
2,061
1,191
5,350
8,602
1826
505
1,115
4,271
5,891
1827
508
1,140
7,383
9,031
1828
320
3,555
8,510
12,385
199
12,584
1829
720
6,076
7,044
13,840
668
14,508
1830
415
1,788
9,115
11,318
934
12,252
1831
540
1,442
9,707
11,689
918
12,607
1832
646
3,184
I1,399
15,229
579
15,808
1833
361
1,786
11,293
13,440
1,059
14,499
1834
377
3,336
17,280
20,993
2,077
23,070
1835
268
3,770
22, 123
26,161
6,758
32,919
1836
535
1,698
21,013
23,246
9,046
32,292
1837
179
2,216
22,306
24,701
14,521
39,222
1838
964
3,410
22,161
26,535 19,868
46,403
1839
1,812
2,637
23,613
28,062 24,092
52,154
1840
752
1,525 20,166
22,443
35,354
57,797
1841
705
1,180
14,321
16,206
41,364
57,570
1842
1,910
857
15,253 18,020
44,392
62,412
1843
756
1,133
17,600
19,489 40,759
60,248
1844
430
700
20,063
21,193
45,49I
66,684
1845
622
1,914
19,647
22,183
46,643 68,826
1846
549
1,035
17,553
19,137
39,348 58,485
1847
406
340
14,373
15,119
35,700 50,819
1848
268
231
12, 169
12,768
36,728
49,496
1849
734
296
9,934
10,964
32,729
43,693
1850
1,302
144
10,584
12,030
29,556 41,586
1851
468
339 11,661
12,468
24,773
37,241
1852
641
502
10,962
12,105
19,549 31,654
1853
498
553
10,035
1854
737
283
11,288
12,208 24,612
12,086 20,887 32,973
36,820
1855
1,088
173
12,459
13,720 30,500
44,220
1856
681
140
11,395
12,216
30,026
42,242
1857
827
183
8,904
9,914 27,657
37,571
1858
1,064
1,697
11,215
13,976
23,222
37,198
1859
1,514
5,778
12,010
19,302
23,900
43,202
1860
1,515
217
16,297
18,029
21,619
39,648
1861
I,293
267
1862
1,815
1863
1,676
14,801
220 14,364
75 14,751
16,361 21,294
37,655
16,399
23,895
40,294
16,094
27,094 43,596
893
894
APPENDIX.
TABLE No. 16.
TOTAL OF ANNUAL COPPER SALES AT SWANSEA TICKETINGS SINCE 1863,
£ S. d.
107 2
Tons.
Tons.
1861
37,655
5,306
1416
1862
40,294
5,969
14/2/18
IOI
7
1863
43,596
6,196
12816
98 18
1864
32,413
4,632
1441
103 3
1865
25,217
3,791
15
1866
36,158
5,218
14816
1867
31,532
5,132
1868
34,166
16%
5,157
1516
93 17
89 4 0
86 O O
86 3 O
O
1869
28,007
3,912
13316
82 19
1870
14,534
2,329
16
77 6
1871
25,724
4,419
17/16
79 13
1872
24,688
4,230
17층
​99 18
O
1873
26,427
4,639
17116
1874
31,439
5,597
17416
90 14 0
89 0
O
1875
23,053
4,298
188
93 3 O
1876
34,256
5,812
17
87 II O
1877
49,416
6,258
128
82 19 0
1878
35,579
2,910
8 1/1/0
82 10 O
1879
25,452
2,601
10%
78 11
1880
24,396
2,160
81
85 8
1881
19,717
1,666
8
84 9 0
The transactions of the CONSOLIDATED MINES for eighteen years ending 1836, from
Sir Charles Lemon's paper in the "Statistical Society's Journal," vol. i. p. 771.
TABLE No. 17.
Year.
Capital and
Compound
Cost.
Lord's
Dues.
Value of
Ores.
Tons of
Ore.
Wages.
Interest.
£
£
£
£
Tons.
£
1819
15,267
1820
36,644
1821
18,223
1822
3,506
111
| | |
1823
3,479 69,836
3,478
83,438
11,532
43,716
1824
13,001
84,081 4,584
110,036
14,980
47,885
1825
2,768 95,45I
4,971
119,312
13,379
53,275
1826
1,985 82,865
3,848
92,355 13,872
43,200
1827
1,726 81,322
4,108
98,601 13,637
41,439
1828
1,199 69,825
4,103
96,313
13,262
37,568
1829
340 68,177
3,673
88,171
12,578
38,183
1830
Capital)
repaid.} 69,897
3,795
91,092
13,512
39,304
1831
75,290
4,310
103,451
15,292
43,410
1832
83,472
4,791
115,000
15,670 47,051
1833
89,696
5,967 143,227
18,191
51,844
1834
88,956 5,652
135,670 20,022
42,690
1835
1836
90,216
102,007
5,607
6,071
134,574
19,619
53,787
145,717
18,499
61,257
214,045
644,699
APPENDIX.
TABLE No. 18.
895
PRIVATE CONTRACT PURCHASES, SO FAR AS RETURNS CAN BE OBTAINED FROM 1832 TO 1862.
Ore.
Copper.
1832
441
Ore not given.
1833
2,500
540
Ore, Vivian's purchase only.
1834
4,708
469
""
""
1835
2,829
546
1836
5,338
535
""
1837
The British, Colonial, and
7,579
720
""
""
1838
the Foreign ores remain in
6,806
662
1839
these returns undivided.
11,614
1,478
""
Ore of 5 companies; metal of 7 comps.
1840
18,085
2,643
6
""
""
""
7
""
1841
13,313 2,192
""
1842
21,658 3,471
""
1843
26,341 3,739
778
8
""
""
""
""
7
8
""
""
""
1844
29,818
4,108
""
9
ΙΟ
includ-
""
British
1845
14,118
Foreign and Colonial 7,342
21,452
British
1846
10,137
Foreign and Colonial 7,836
17,973
3,902
1847
(British
6,458
Foreign and Colonial 3,002
9,410
1,953
1848 British, Foreign, and Colonial
not distinguished.
13,067
1,577
1849 British, Foreign, and Colonial
cannot be separated; ore in-
cludes 80 tons of copper not
13,492
3,881
given.
1850 British and Foreign uncer-
tain. After this date the
relative quantities of the
British and Foreign copper
cannot be determined.
16,434
4,506
1851
""
1852
""
12,295 4,001
13,889 3,833
1853
""
""
24,633 5,861
1854
1855
""
""
1856
""
1857
""
29,809
10,673
1858
""
""
39,908
13,584
""
1859
""
39,269
12,359
465
621
""
""
""
""
1860
40,383
10,955
""
787
""
""
1861
""
47,496
13,243
""
562
1862
"
35,160
11,304
""
829
""
""
ing 741 tons of metal from Anglesea ore.
4,099 {Copper includes 722 tons made at Amlwch;
17,366 5,425
27,302
7,238
29,423 7,476
the ore not given.
Copper includes 664 tons at Amlwch; the
ore not given.
Copper includes 535 tons Amlwch, the ore
of which is not given.
Including Amlwch copper 432 tons.
Including Amlwch copper 614 tons, and
1,649 tons of copper from Foreign ores
not given.
Including 671 tons Amlwch, and 1,406
Foreign copper; ore not given.
Including 734 tons Amlwch, and 1,440 tons
Foreign copper; ore not given.
Including 517 tons Amlwch, and 937 tons
of Foreign copper; ore not given.
Including 586 tons Amlwch and 1,689 tons
copper (British or Foreign not stated);
ore not given.
Including 572 tons Amlwch copper.
""
""
""
540
572
(Gren-
fell & Co. and Ravenhead Co. not in-
cluded.
Including 524 tons Amlwch copper.
TABLE No. 19.
AVERAGE PRICES PER TON of Copper Ore and OF METALLIC COPPER IN EACH YEAR SINCE 1855.
Year.
Copper Ore.
Metallic Copper.
Year.
Copper Ore.
Metallic Copper.
1855
# ;
S.
d.
8 O
£
S.
d.
129 O
1856 6 2 6
123
1857 6 8 6
124
1858 5 18 6
108
£
1869 4 3 6
1870
1871
1872 4 13
S.
d.
£
S.
d.
4
1859 5 17 6
112 7 6
1873
4
1860 5 19
109 13 IO
1874
4
1861
5 16
102
I2
1875
3300 3∞ 50
77 10 O
72 13 O
18 6
77 ΙΟ O
104 5
8
1862
5 14
100 12
1863
4 19
98 17
1864
5
3
ΙΟΙ
1865 4 18
94
1866
4 II O
91
14
1867 4 7 O
82
1868 4 II O
78 15
27∞ 740 5
1876
4 17
83
1877
4
8
1878
1879
1880
8
6
1881
6
1882
3+43
-0∞+50
6
8 6 64
4
6
5 6 68
16
O
Doming Fog
95 18
89 12
90 O о
6
2
75
16
68
II
69
155
6
6
73
896
APPENDIX.
TABLE No. 20.
COST, ETC., AT FOWEY CONSOLS MINE.
Furnished by Mr. Austin Treffy, of Fowey, for 1837.
Quantity of ores raised in 1837 in FOWEY CONSOLS MINE
£
Amount of proceeds for the ores sold, including carriage money paid for the same 89,083 15 2
Total expenses for the year
15,710 tons 12 cwts.
S. d.
•
•
73,262 16 3
Amount of profit
•£15,820 18 11
The expenses are given under the following heads :—
Amount of agency, including purser and clerks,
lord's dish or dues
smithery, carpentry, and sawing
tutwork.
""
""
""
tribute
""
•
"
sundry surface labour and sundries
""
५५
S. d.
1,361 3 6
4,886 2 II
1,701 19 0
16,347 IO IO
18,821 7 11
3,392 6 5
""
""
paid to sick labourers of both sexes from the sick club*
""
paid for medical attendance
charges on ores, including carriage and sampling and weighing 5,956 2 O
drawing, filling, and landing
parochial rates
2,229 19 I
292 16 6
607 2 O
•
324 10 5
""
rent of water and engine charges (exclusive of coals)
2,247 12 3
stores
15,094 3 5
Total expenses †
• £73,262 16 3
TABLE No. 21.
MONA MINE, ANGLESEA.
Year.
Copper Ore
Copper.
Precipitate. Copper in Precipitate.
Blue
Stone.
Tons.
Tons cwts. qrs. lbs.
Tons.
Tons cwts. qrs. lbs.
Tons.
1855
226
8 O O
1856
1857 4,507
207
IO O
1858
5,026
174
I O
1859
4,688
179
I I
1860
3,145
147
1861
1862
+∞
2,215
ΙΟ
82 16
2,752
104 14 0
888
842
64 15
66 19
1863 2,425
99 14 I
1864 2,545 II4 0
1865 2,656 II2 I2 I O
1866 3,286
147 17
1867 2,242
91 15
1868 2,592
144 4 I ΙΟ
1869
2,324 151 O
1870 3,500 227 IO
H3TH & HO
664
459
391
I
21
876
2 о
508
542∞∞
58
о
43 18 2
28 19
87
12
82
4
707
74
O 3
333N 2 TOM
I
I
6
1,221
O O
765
1,078
879
I,200
| |
200
984
1871 3,000
195
1872
2,400 156 O
1873
1,628
105 16
297
26 14
2 о
1874
150
9 15
282
25
7
O O
414
1,008
1875
600
1876
800
| |
430
Not known.
500
332
""
50
1877
1,040
1878
1,022
1879
767
332
38 0 о
270
35 15
O
O
37
6
393
40
O
360
27
ΙΟ
202
26
548
1880
2,019
Not known.
166
O
"9
409
1,569
1,469
1882 2,611
66
520
1881* 3,804 152 5 0 0
* Each miner in those mines received 30s. per month during illness, and had medical attendance with
medicine provided for himself and family, for the support of which a deduction of .Is. 9d. was made upon
his monthly earnings.
+ The expenses in 1836 were £74,960 5s. 10d.
APPENDIX,
TABLE No. 22.
RETURN OF COPPER FROM PARYS MOUNTAIN MINE, Anglesea.
Year.
Copper
Ore.
Copper.
Value of Ore.
Tons.
1855
Tons cwts. qrs. lbs.
412 6
£ S. d.
Preci-
pitate.
Tons.
Copper in Precipitate.
Tons cwts. qrs. lbs.
O
1856
No return.
1857
4,864
243 9
1858
4,858
227 15
1859
3,698
188 I
O
86
O O
1860
4,568
.268 II 2
1861
5,260
295 17
2
13,620 0 0
399
41 17
1862
5,398
305 17
о
28,421 7 3
359
38
O
1863
5,027
337 O
25,876 4 4
327
39
O
1864
4,565
306 O
1865
4,468 291 ΙΟ
26,159 16 5
296
35
о
269
25
1866
4,084
265 10
16,437 17 6
271
24
ΙΟ
1867
3,526
150
1868
2,908
189
+0
232
22
10,868 6 0
239
21
TOON N
50
78
I
O
2 O
2 5
LO
1869
2,569
241
1
1870 2,270 147 II
1871 2,508 163 о
1872
2,813
182 I
OOO
O
204
18
| |
168
15
155
13
1873
1,938
125 19 I
3,683 7 II
120
ΙΟ
ower ∞
19
16
1874
3,343
62 ΙΟ
O
4,633 8 II
120
10 15
∞ 6 96 S
8
O
2
O
O
O
O
О
1875
2,704
1876
2,323
11
6,028 II 6
206
3,893 2
5
187
| |
1877
2,153
42 15
1878
320
6
7
1879
180
4
IO
O O O
O O O
3,200 14 9
150
19
12
704 4
151
ΙΟ 13
1880
960
540 O
1,657 8
O
100
I2
13
1881
863
34 ΙΟ
1882
937
1,381 2 5
1,160 19 4
11
109 15 3
119 5 3
200mm
99
897
TABLE No. 23.
AN ACCOUNT OF THE FINE COPPER PRODUCED FROM THE MONA AND PARYS MINES,
SMELTED AT Amlwch, BETWEEN THE YEARS 1820 AND 1835.
Years.
Mona Mine.
Parys Mine.
Totals.
1820
Tons cwts. qrs. lbs.
417 15 2 17
1821
329
ΙΟ
1822
412
1823
311
1824
1825
334 7 I
394 17
277
3 22
3 26
17
7
I 20
Tons cwts. qrs. lbs.
201 19
228
361 19
393 13
19
289 10 0
1826
374 O 3 24
1827
363 12
1828
378
1829
394
1830
526
1831
580
1832
513
1833
1834
328 12
375
1835
333 9 O 19
O MN NO NH MN MO
562 32
27
341 13 2
410 12
2
16
317
6
2
I2
379
4
2 2 2 HON HM2
2
26
I
15
I
9
623 17
17
736 10
I
21
784 13
Tons cwts. qrs. lbs.
619 15 O 19
558 8 2 20
774 2
705
I 27
2
2 O
3 16
I 17
25
3
O
680 19
I
16
20
757 ΙΟ
I
O 25
331 14
I
O
2 25
252 II 2 II
I
12
335 13 O 2
3
I
270
2
8
176
7 3
5
261
220
0548
O
O
NOO
IO
O 25
726
778 14
915 16
783 2 3
504 17
636 12
I 25
I
соста
8
I 14
2 18
553 17 3 19
MNOM
I
2
18
2
898
APPENDIX.
TABLE NO. 24..
PRODUCTION OF LEAD ORE, LEAD, AND SILVER IN THE UNITED KINGDOM IN EACH YEAR FROM
1848 TO 1871.
(The last ten years being given on page 836.)
Year. Lead Ore.
Lead.
Silver.
Year.
Lead Ore.
Lead.
Silver.
Tons.
1848
78,944
Tons.
53,373
Ounces.
Tons.
Tons.
Ounces.
1860
88,791
63,225
549,090
1849
86,823 58,715
1861
90,666
65,644
570,474
1850
92,958 64,429
1862 95,312
69,013
686,123
1851
92,312 65,289
1863 91,281
68,221
634,004
1852 91,198 64,961
1864 94,463
67,081
641,088
1853
85,843
60,969
496,475
1865
90,452
67,251
724,856
1854
90,554
64,005
562,659
1866 91,051
67,391
636,688
1855
92,251
65,691
561,906
1867 93,432
68,441
805,394
1856
101,997
73,129
614,188
1868
95,236
71,017
841,328
1857
96,820
69,266
532,866 1869
96,866
73,259
831,891
1858
95,855
68,303
1859
91,353 62,382
569,345 1870 98,176
578,275 1871
73,420
784,562
93,965
69,037
761,490
TABLE No. 25.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF Cornwall
IN EACH YEAR SINCE 1845.
Year.
Lead Ore.
Lead.
Silver.
1845
Tons
10,110
cwts.
Tons cwts.
Ounces.
O
6,063
O
1846
8,228
4,933
1847
II,574
7,304
1848
10,223 O
6,614.
1849
10,494 O
6,614
1850
10,325 16
6,773
1851
9,515 4
6,709
1852
8,998 14
6,220
1853
6,680 3
4,690
1854
7,460 I
5,005
IO
1855
8,962 19
5,882
1856
9,973 13
6,597
1857
9,559 16
6,036
mono∞
847
255,640
6
250,008
5
165,670
179,675
211,348
248,436
224,277
1858
9,710 0
5,436
15
223,189
1859
7,842 15
1860
6,401
1861
6,690
14
1862
6,030 5
3344
4,985 12
215,964
4,242 15
180,757
4,228
20
173,344
4,119
O
205,662
1863
6,259 14
4,270
15
206,313
1864
5,301 17
3,538
I2
192,232
1865
6,546 II
4,296
8
214,659
1866
6,736 ΙΟ
4,350
I I
195,218
1867
8,644 19
6,480
II
314,326
1868
8,415 16
6,310
9
303,033
1869
9,023
1870
8,481
πω
6,775 O
305,714
5
6,360
O
292,045
1871
7,565
14
5,672 18
267,234
1872
5,463 IO
4,098 15
1873
3,909 IO
2,923
1874
3,119 14
2,337
1875
2,566 ΙΟ
1,932
1876
2,727 о
2,070
1877
2,166 13
1,673
17
1878
I,394 14
1,022
1879
725
5
544
18
1880
753
18
1881
764 17
1882
624 I
∞ 78
570
408
SO32 O 7 2 ∞ 5∞ 1
207,710
129,509
85,304
25,681
37,650
23,035
16,456
9,435
11,750
8
454
I
14,396
11,460
APPENDIX.
TABLE No. 26.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF DURHAM AND
NORTHUMBERLAND SINCE THE YEAR 1845.
Year.
Lead Ore.
Lead.
Silver.
Tons cwts.
Tons cwts.
Ounces.
1845
17,046
O
11,236
1846
16,944
O
11,281
1847
19,188
O
12,913
1848
18,815
O
13,178
1849
18,929
18
13,215
1850
21,010 5
15,840
4
1851
21,163 14
15,488
12
185,860
1852
21,594 3
15,978
II
131,726
1853
19,287 16
15,041 4
74,700
1854
22,329
1855
22,107
Ки
15
16,669 18
78,577
18
16,309
19
75,435
1856
24,125
7
17,674 II
79,924
1857
21,580 I
17,073 14
74,091
1858
19,996
2
16,776
78,238
1859
19,571
O
14,568
74,222
1860
20,200 12
15,186
O
84,254
1861
19,536 15
15,252 17
78,265
1862
21,771 18
16,454 O
82,854
1863
22,774 2
17,205 II
81,315
1864
23,029 19
16,656 12
78,454
1865
21,501 14
16,881 ΙΚ
68,887
1866
22,555 15
16,974 12
72,300
1867
22,574 2
16,119 6
77,678
1868
23,720
17
17,805
8
81,447
1869
20,793
I
17,177 6
85,398
1870
21,693 O
16,704 ΙΟ
66,464
1871
21,864 14
16,614 2
75,776
1872
19,106 IO
14,399
4
72,175
1873
18,623 II
13,769
1874
18,839 9
15,689 12
1875
22,304 4
16,525 7
1876
23,285 9
16,730 3
1877
25,086 ΙΟ
18,984 15
1878
16,869 O
13,190 14
1879
14,186 ΙΟ
10,708 2
1880
18,254 19
15,803
1881
17,467 2
13,089
1882
16,729
I
13,206
16
FONAMIINOLO
9
47,862
70,336
70,191
74,095
75,686
58,318
44,552
6
74,630
5
54,036
52,049
TABLE No. 27.
AN ACCOUNT OF THE GREENWICH HOSPITAL DUTY LEAD ORE FROM THE YEAR
1768 TO 1881.
Year.
Lead Ore.
Lead Ore.
Year.
Lead Ore.
Lead Ore.
1768
1769
Bings
2,704
4,246
cwts.
1770
1771
3,268
3,006
3352
Tons
1,081
1,698
cwts.
15 1784
II 1785
Bings cwts. Tons
3,751
2,798
7
cwts.
1,500 15
1,307
9 1786
3,109
1772
1773
2,867
6
I,202
I,147
ΙΟ 1787
3,43I
2
1788 3,109
3,146
1774
1775
3,763
4,840
1776 3,715
1777
1778
3,263
3,927
1779 3,792
2 444 2 2 2
1,258
IO 1789
1,505
8
1790
1,936
2,659
2,868
1791 2,807
1,486
2
1792 3,408
1,305
6
1,570
18
1793 4,103
1794 5,146
1,516
18
1795
3,455
1780 4,235
I
1,694
I 1796 3,702
1781
3,373 6
1,349
ΙΟ
1782
3,007
6
1,203
1783
3,732
2
1,492
18
2∞
1797
1798
4,094
3,836
1799
2,435
7736 0433442 2 462
1,119
II
1,243
19
1,372
II
1,243
1,063
18
12
5 1,147
9
1,122
19
1,363
7
5
1,641
9
2,008
12
1,382
1,480 18
1,637 16
1,534 14
2∞
974
4
899
3 M
900
APPENDIX.
TABLE NO. 27 (continued).
Year.
Lead Ore.
Lead Ore.
Year.
-Lead Ore.
Lead Ore.
1800
Bings* cwts.
2,526 I
1801 2,511 6
Tons
Ι,ΟΙΟ 9
cwts.
Bings cwts.
Tons cwts.
1830
3,505
6
1,402 6
1,004 14
1831
3,003
1802 2,917
1803
3,097 5
1804
3,365
1805
2,944
1806
2,414
1807
2,484
1808
3,202
1809
2,867
75435533x
1,167 3
1832
2,630
1,239 I
1833
2,316
1,346
4
1834
2,106
1,177
15
1835
2,283 Ι
965
17
1836
2,154 5
993
17
1837
2,233 3
1,281
I
1838
2,322
1,147 I
1839
2,063
1810
1,987 6
795
2
1840
2,004
1811
2,210 6
884
6
1841
2,417
1812
2,129
O
851 12
1842
2,462
1813
2,618
3
1,047 17
1843
2,837 Ι
1814
2,294 I
917 13
1844
2,501 7
32N3ALOMINOWAN
I,201
7
1,052 2
926
ΙΟ
842 II
913
861 17
893
929
825
801 17
967
985
57744
I
1,134 17
1,024 15
1815
2,287
1816
2,120
1817
2,743
1818
3,558
1819
3,563
1820
4,349
1821
4,854
1822
4,795
1823
4,768
1824
5,486
1825
5,757
1826 4,858
1827 4,842
1828
1829
4,399
4,156
61335254 2 O NOSSO
915 2
1845
2,441 7
976 15
755
I
849 13
1,097
7
Returns not obtainable in the
same form until 1871.
1,423 7
1,425 9
1871
1,631
1,739 14
1872
1,941
17
1873
1,918
1,907
2,194
7
2,303
1,943 ΙΟ
+6030
1874
1,444
1,214
926
1875
1,004
13
8
1876
Bings not re-
1,406
1877
turned.
1,680
1878
1,636
5
1,937 I
1879
1,759 17
1880
1,433
I,409
7262 37∞∞ ●
8
O
1,662
14
1881
1,445
6
TABLE No. 28.
AN ACCOUNT OF THE LEAD ORE, LEAD, AND SILVER PRODUCED FROM THE
ALLANDALE EAST AND WEST AND WEARDALE MINES FROM 1845 TO 1881.
Year.
Lead Ore. Lead.
Silver.
Year.
Lead Ore.
Lead.
Silver.
Tons.
Tons.
Ounces.
1845 12,200 8,130
1864
Tons.
12,006
Tons.
Ounces.
8,608 42,949
1846 12,000
8,000
1865
10,301
8,505 45,464
1847
13,600
9,300
1866
9,712
8,197 42,126
1848 13,230
9,080
1867
11,310
7,771 42,287
1849 13,362 9,162
1868
12,360
9,650 44,876
1850 13,380
9,804
1869 10,402
9,407 52,486
1851 13,560 9,977
1870
10,259
8,225
37,988
1852 13,840 9,313
1871
10,507
8,021 45,988
1853 11,916 19,904 50,700
1872
8,895
6,760
37,180
1854 12,220
1855
12,007
1856 I1,900
9,200
9,031 51,825
49,000
1873
8,370
6,095 19,208
1874
7,486
7,152
41,486
9,437
56,662
1875
9,052
6,322
30,847
1857
10,674
8,974 53,603 1876
8,260
5,287
23,990
1858
8,8orf
8,448 47,575 1877
9,821
7,367
30,896
1859
9,473
7,659 42,758
1878 4,267
3,594
21,157
1860
8,950
6,925 39,240
1879
1,624
1,218
6,090
1861
9,700
1862 10,714
1863
10,728
8,120 46,080 1880
8,300 45,840
8,482
3,910
5,0798
37,669
1881
3,273
2,454
16,968
44,613
The Bing is 8 cwts.
+ Ore raised in the year ending June, 1858.
+ Lead made in the year ending December, 1858.
? A considerable quantity of this was obtained from lead ore raised in 1879.
APPENDIX.
TABLE No. 29.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF CARDIGANSHIRE
IN EACH YEAR SINCE 1845-
Year.
Lead Ore.
Lead.
Silver.
Tons cwts.
Tons cwts.
Ounces.
1845
5,726
O
3,716
1846
5,718
15
3,712 ΙΟ
1847
4,899
3,176 ΙΟ
1848
4,882
1849
5,988 15
1850
6,687 15
1851
7,182 18
0550
3,180
O
3,895
0
4,768
12
5,809 7
87,135
1852
7,370 ΙΟ
5,305 8
79,575
1853
6,552 15
4,909
19
30,477
1854
7,034 O
4,948 15
33,418
1855
7,043
1856
8,560
31
5,014
8
28,079
I
6,191 IO
38,751
1857
7,573 9
5,509 12
37,097
1858
7,086 12
5,440
3
41,100
1859
7,466 14
5,569
9
37,787
1860
7,355 I
4,952
15
44,807
1861
7,755 5
5,886
2
54,989
1862
8,299 IL
5,443
2
62,678
1863
7,131 17
5,661
12
58,846
1864
7,464 3
4,452
14
46,486
1865
7,835 6
5,877
I
54,617
1866
7,700 I
5,799
17
61,455
1867
7,838 18
5,866
7
63,113
1868
7,230 14
5,414 ΙΟ
67,502
1869
8,180 4
6,216 II
66,145
1870
7,307 5
5,532 IO
56,553
1871
7,552 19
4,692 16
46,980
1872
6,764 3
4,998 13
41,690
1873
5,372 19
4,056
19
39,869
1874
5,423 4
4,075 II
41,047
1875
5,835
4,401
17
46,624
1876
5,961 16
4,468
19
45,418
1877
5,849 18
4,644
6
47,284
1878
6,801 8
5,143
49,028
1879
5,079 12
3,990 6
42,770
1880
6,404 14
5,016
15
49,445
1881
4,598 3
3,381
II
28,765
1882
4,036
13
3,157
IO
29,626
TABLE No. 30.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF THE ISLE OF MAN.
IN EACH YEAR SINCE 1845.
Year.
Lead Ore.
Lead.
Silver.
Tons cwts.
1845
2,259
O
Tons
1,523 O
cwts.
Ounces.
1846
2,316
O
1,663
1847
2,575 O
1,699
1848
2,521 O
1,665
1849
2,826 IO
1,535
I
1850
2,175
1,218
19
1851
2,500 O
1,402
ΙΟ
1852
2,415 O
1,835
5
33,980
36,700
1853
2,460 O
1,829
1854
2,800 O
2,137
OO
47,105
52,262
1855
3,573
5
2,725
51,597
1856
3,217 18
2,450 18
60,382
1857
2,656 O
2,027 15
48,016
1858
2,457 O
1,880
19
46,985
1859
1860
2,464 O
2,810
1,880
ΙΟ
56,974
O
2,091
9
60,170
951
3 M 2
902
APPENDIX.
TABLE NO. 30 (continued).
Year.
Lead Ore.
Lead.
Silver.
Tons cwts.
Tons
cwts.
Ounces.
1861
2,717 19
2,403
8
67,282
1862
2,508 12
1,861
O
70,592
1863
2,561
11
2,012
74,289
J
1864
3,118
2
2,350
5
125,020
1865
3,142
2,321
123,221
1866
3,494
8
2,571
II
147,516
1867
3,799
2,834 O
165,170
1868
4,290
3,089
1869
4,302
3,117 15
1870
4,604 IO
3,266
1871
4,645
3,334 12
1872
3,529 O
2,639
1873
4,371 I2
3,131
1874
4,204 14
3,185
1875
4,429 O
3,158 ΙΟ
1876
4,353
1877
4,464
1878
3,920 13
1879
4,358
I2
1880
5,118
18
1332∞
I
3,086 I
-ÖWONNOûter
178,718
172,839
172,528
176,331
2
145,433
163,058
161,612
183,524
170,105
3,342 12
186,019
2,995 9
110,496
3,267 O
100,476
3,886 5
59,667
1881
5,675
4,183 12
84,865
1882
5,494
4,267 17
129,769
TABLE No. 31.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF SCOTLAND IN EACH YEAR
SINCE 1845.
Year.
Lead Ore.
Lead.
Silver.
•
Tons cwts.
Tons
cwts.
Ounces.
1845
1,173
901
O
1846
1,161
942
O
1847
1,159
822
ΙΟ
1848
2,588
1,736
O
1849
1,421 15
1850
3,117
1851
3,113
550
957
2,124
2,140
50
6,576
1852
3,499
2,381
7
19,048
1853
2,799
7
1,919
5,860
1854
1,753 II
1,278
19
5,426
1855
1,587
1,159 12
4,947
1856
1,931
O
1,416 12
5,289
1857
1,890 9
1,351
4,206
1858
2,290 ΙΟ
1,585
II
4,882
1859
I,942
9
1,347
9
4,022
1860
1,973 15
1,358
15
3,140
1861
1,761
I
1,229
16
4,133
1862
1,767 5
1,262
6,190
1863
1,455
ΙΟ
1,086
6,006
1864
2,072 16
1,591
7,843
1865
2,363 17
1,774 17
8,704
1866
2,423 18
1,730
ΙΟ
8,704
1867
2,954
2
2,107
19
11,428
1868
2,436
13
1,811
13
8,201
1869
3,181
I
2,271
16
7,797
1870
3,353
15
2,390
2
5,680
1871
3,392 19
2,449
4
5,285
1872
3,605 5
2,331
7
5,900
1873
3,207
I
2,125
10,720
1874
2,931
I
2,073
11,317
1875
4,109 14
3,078
ΙΟ
13,303
1876
3,910
4
2,936
6
12,214
1877
2,706 16
2,105
2
11,306
1878
4,236 O
2,743
O
14,320
1879
3,702 II
2,770
15
12,075
1880
3,956 13
2,848
I
14,379
1881
3,806 17
2,839
15
13,412
1882
4,401
I
3,376
12
27,435
TABLE NO. 32.
AN ACCOUNT OF THE PRODUCTION OF THE LEAD MINES OF IRELAND IN EACH YEAR
SINCE 1845.
Year.
Lead Ore.
Lead.
Silver.
Tons
cwts.
Tons
cwts.
Ounces.
1845
1,944
855
ΙΟ
1846
1,641
811
1847
2,251
1,380
1848
1,912
1,188
O
1849
2,739
1,653
14
1850
2,895 6
1,746
I
1851
3,222
16
1,829
7
13,810
1852
4,493 14
3,222
18
32,220
1853
3,309 ΙΟ
2,452
7
17,664
1854
3,069 15
2,210
IO
18,096
1855
2,405 15
1,732
7,252
1856
2,483
17
1,602
5
3,700
1857
2,298 19
1,407
3
3,071
1858
2,603 IO
1,704 20
14,361
1859
2,477
ΙΟ
1,613
15
13,998
1860
2,433 15
1,563 20
14,365
1861
2,403
O
1,592
12
12,398
1862
2,643
20
1,763 2
12,481
1863
2,412
ΙΟ
1,608
13
1864
2,201
20
1,441
1865
1,777 12
1,334
1866
1,822 16
1,224
1867
1,882
12
1,308 O
1868
2,089 0
1,562 ΤΟ
1869
1,979
1,478. 19
1870
1,415 ΙΟ
1,061 12
1871
1,115
834
15
1872
962
726
1873
1,180
885
1874
1,752
14
1875
1,850
1876
1,825
1877
1,655
18
+∞ +∞
1,313
12
8
1,387
mrtnog ON LLON∞
13,165
15,534
4
16,830
5
15,039
12,140
14,372
5,480
2,815
1,040
4,420
6,555
18
6,935
4
1,368
18
6,840
1,241
6,205
1878
1,704
I
1,263
ΙΟ
5,650
1879
1,272
9
911
O
4,000
1880
I,244
19
931
15
1881
848 16
636
1882
992
4
733 13
423
3,360
4,932
4,988
TABLE No. 33.
PRICES OF LEAD AT GRASSINGTON PAID AT THE SMELTING HOUSE FOR DUTY LEAD.
Year.
Lead.
Price per Ton.
Year.
Lead.
Price per Ton.
Year.
Lead.
Price per Ton.
£ S.
1780
II
1781
12
1782
1783
1239
18
16 13
19 12
1784
16 8
1785
16 I
1786
16
57∞ 32∞ 12
d.
£ S. d.
b
S. d.
6
1802
6
1803
27
O
1804
28
1805
27
478 Es
24 16
6
1823
22
5 O
15
6
1824
O
II O
1825
1826
2 2
21
25
19
1806
35
I2 6
1827
18
O
1807
30
3 6
1828
17
1808
30 I
O
1829
14
1787
21
4
1809
31
3
O
1830
12
2607053
O
6
1788
21 ΙΟ
1810
28 16
1831
12 4
O
1789
19
17
6
1811
24 O
1832
II
13
4
1790
16
1791
18
1792
19
1793
19
1283
6
1812
6
1813
1814
1815
1794
14 IO
1816
1795
16 15
1817
2 2 2 2 11
23
3
1833
12
12
О
25 14
1834
16
II
8
26 JI
1835
17 9
6
20
16
1836
24
2 IO
16
5
1837
19 3
6
18
5
1838
18
9 9
1796
18
6
1818
27
6
1839
17
2
ΙΟ
1797
16 17
O
1819
22 II
1840
18
6
4
1798
15
1799
1800
1801
22
56 96r
7
1820
21 IO
6
1841
18 14
8
16
9
19 16
1821
22 ΙΟ
1842
16
IO O
1822
22 7
1843
16 5 0
8 6
904
APPENDIX.
Year.
English Lead,
per Fodder.
TABLE No. 34.
PRICES OF ENGLISH LEAD PER FODDER,* FROM THE YEAR 1783 TO 1828.
Year.
English Lead,
per Fodder.
£
S. d.
£
S.
d.
1783
18 14
2
1806
39 18
4
1784
17 ΙΟ
0
1807
35 O
ΙΟ
1785
17 18
3
1808
31 18
1786
17 15
IO
1809
39 15 O
1787
20
4
7
1810
36 18
1788
23
2
I
1811
30 14
1789
21
8
9
1812
29
ΙΟ
1790
18 16
O
1813
29 16
1791
19 13
4
1814
31 II
1792
20 15
O
1815
26
9
1793
20
1794
19
1795
18
1796
21
1797
19
IO
1798
19
1799
2I
1800
21 18
no
moomma
5
ΙΟ
1816
20
18
O
1817
19 8
3
I
1818
25 IO
420∞∞ 0440
8
6
3
1819
24 15
IO
O
1820
3
33
1821
4
1822
1823
1801
25
18
1824
2 2 2 2 2
21
22
NEW
23 IO
O
2 6
13
23
IO
1802
30 10
1825
1803
33 5
1826
1804
33 O
1827
23
27 15
22
20 II
1805
37 16
8
1828
19 6 8
552 I6
6
TABLE No. 35.
AN ACCOUNT OF THE ZINC ORE AND METALLIC ZINC OBTAINED FROM THE MINES OF THE
UNITED KINGDOM IN EACH YEAR FROM 1856 TO 1882.
Metallic Zinc
(Spelter).
Year.
Zinc Ore.
Metallic Zinc
(Spelter).
Year.
Zinc Ore.
Tons cwts.
Tons cwts.
Tons cwts.
Tons cwts.
1856
9,003 O
1869
15,532 O
4,500 O
1857
9,289
1870
13,586
3,936
1858
11,556 2
3,466 O
1871
17,736 10
4,966
1859
13,039 O
3,697
O
1872
18,542
O
5,191
1860
15,552 14
4,357
1873
15,969
I
4,471
1861
15,770 O
4,415
1874
16,829 16
4,470
1862
7,497
I2
2,151
1875
23,978
O
6,713
1863
13 699
1864
1865
15,047
17,842 15
1866
1867
12,769
13,489
120300
3,835
4,040
1876
23,613 8
6,641
1877
24,405 16
6,833 ΙΟ
4,460
1878
25,438 2
6,309
O
3,192
IO
1879
22,200
O
1880
3,750 O
27,547 15
5,554 O
7,162
1868
12,781 13
1881
3,713 O
35,527 7
1882
32,479 14
14,947 5
16,118 9
"A Fodder of Lead at the Mines contains twenty-two hundred and a-half weight, though in
London but twenty hundred weight." ("Collection of Scarce and Valuable Treatises upon Metals, Mines,
and Minerals." Printed for J. Hodge, at the Looking Glass, on London Bridge, in 1740.)
APPENDIX.
TABLE No. 36.
AVERAGE PRICES OF ZINC ORE AND METALLIC ZINC IN EACH YEAR SINCE 1858.
Year.
Zinc Ore.
Metallic Zinc
(Spelter).
Year.
Zinc Ore.
Metallic Zinc
(Spelter).
£ s. d.
£
S. d.
1858
25 5 0
1859
300
21 O
1860
2 10 O
20 II
1861
2
1862
2
1863
2
1864
3 0
027O
O
17 18
18 6 6
jomo to
£ s.
1870
3 9
OP
1871
3 15
1872
4
a.
£
S.
18 16 6
18 II
22 15 O
d.
6
1873
3 15
26 15
1874
3 7
23
18 2
1875
4 2 3
24 5
22 2 6
1876
4 12 O
24 3
1865
2 18
20 12 O
1877
3 17 4
21 15
1866
3 6
21 18
1878
3 7
19 10
1867
3
1868
I
1869
336
346
21 6
1879
393
17 5
20 6 4
1880
4
I
19 4
20 10 8
1881
368
16 18
O
TABLE No. 37.
IMPORTS AND EXPORTS OF ZINC FROM 1823 TO 1858.
905
Duty
per Ton.
Year. Imports.
Exports Total
to India. Exports.
Home
used.
Highest and
Lowest Prices.
Remarks.
£28 10s.
{
1823
1824
Tons.
5,400
Tons.
Tons.
Tons.
£
S. £ S.
4,536 4,700
22 o to 23
O
9, 199
7,185
8,068
24
24
24 O
,, 23
O
1825
5,556 4,835
6,112
171
22 IO
14S.
1826
4,839 7,374
8,330
I25.
1827 5,999 5,535
6,929
22
290
28 O
1828
4,566 4,806
4,943
536
1829
4,230 3,505
3,964
IOS.
1830 4,422 3,385
3,479
""
1831 3,821 2,896
3,134
941
II 5,,
1832 3,140 2,044
2,995
1,093
IO IO
""
16 10
›› 41 10
O
,, 15 10
,, 14
14 10 11 13
684. 12 O 9 9/6
843 9 10 II о
""
""
9 5
II O
Beida Co. speculation.
our
All exported to India for
seven years, with low
prices there (from 14 to
5 rupees), while
market was similarly af-
fected downwards from
the glut of that impor-
tation.
1833 2,800
1,225
1,883
1,355
IO IO
12 O
""
1834
2,100
882
1,419
1835 6,500
2,497
3,943
2,205
1836 8,600
I,490
6,269
2,184
1837
4,380
1,811
3,200
2,335
2S.
1838 6,265 528
1,858 3,596
3,391 4,560
1839 8,910 1,538
1840 4,965 2,687
1841 6,509 990
1842 5,500 1,584
""
""
17 O
23 10
12
o
15 10 20 O
18 5 " 21 15
4,091 4,181 20 O ,, 23 10
I,400 3,665
23 10 40 O
""
Gradual revival for 4 years.
Commercial panic in summer.
Natural level for 3 years.
Pottinger's speculation and
36 0,, 24 0 sales the following year.
1,756 I2 O 14 10
""
15 O
", 17
16 10
""
18 10
1,900
2,641
36 0
1843
10,173 3,459 6,445
4,125
23 0,, 22
O
IS.
1844
10,393 5,826
5,925
5,388
22 5,9
IO
O
1845
12,903 2,969 3,084
7,459
22
5,, 15 O
Steady at natural level.
1846 II,434 4,875
4,967
8,450
22 O
" 19 10
1847 12,729
3,301
3,631
11,794
22
O
19 10
1848
13,525
2,831
3,773
9,344
1849
15,915 3,927
5,397
8,726
1850 18,626 3,121
4,537
1851
22,986
2,417
5,553
16
Free
1852 18,505
456
7,252
II,262 15 O " 17 10
5,, 15
15 0
14 5,, 19 15
19 15,
15 0
""
13 O
16 5
French Revolution.
Late speculative position
and present state of
market.
(May 1)
1853 23,418 925
12,643
19 10
,, 24 5
1854 19,583
2,766
8,359
20
о
,, 25 10
1855 17,852 2,741
5,156
22 5,, 25 O
1856 18,213 2,588
5,428
23 15,
1857 18,001 2,269 3,504
1858 23,725 5,053
28 15
23 10 " 31 10
7,731
22 15,, 27 IO
TABLE 38.
PRODUCTION OF MANGANESE FROM 1872 TO 1881.
1872.
1873.
Name of Mines.
Tons cwts. qrs.
Tons cwts. qrs.
1874.
Tons cwts. qrs.
1875.
Tons cwts. qrs.
1876.
Tons cwts. qrs.
1877.
Tons cwts.qrs.
1878.
1879.
1880.
1881.
Tons cwts.qrs.
Alliford
Chillaton and Hogstor
7,681
40 0 0
o o
Bamfylde
Narracolt
8,254 o o
50 o o
153 0 0
5,054 10 0
2,754 7 I
Tons cwts.qrs.
2,430 o o 2,159 0 o 1,000 0 0 400 0 0 800 oo 1,224 o o
Tons cwts. qrs.
Tons cwts. qrs.
Newton St. Cyrus
Shirwill and Braton
Cot Quarry, Barnstable
Devonshire.
Edgcombe.
Longstone
•
Rostidgon and Deep Level
Ruthers
St. Stephen's
Ludcott and West Down
Riley, Ilsington
Coad's Green
Bawden Common
Perran New Iron Mine
Greystone Wood
Monkstone
Stannacombe
| | | | | | | | | | | | |
191 8 0
115 0 0
304 0 6
36 0 0
68 0 0
109 0 6
129 0 0 287 0 0
200 0 0 40 0 0
17 0 0
50 o o
40 0 0
20 0 0
37 0 0
IO O O
50 o o
60 00
24 II
IO O O
| | | | | | |
| | | | | |
O
25 0 0
16 0 0
118 0 0
21 0 0
76 0 0 19 0 0
49 4 O
35 0 0
| | | | | |
| | | | | | |
722 12 0
300 0 0
37 0 0
60 o o 45 0 0
42 0 0
0 70 0 0 150 0 0
រ
20 o o
57 o o
40 0 0
720 0 0
40 0 0
GLOSSARY OF TERMS
EMPLOYED IN, OR RELATING TO, METALLIFEROUS MINING IN THE BRITISH ISLES.
ADIT. From the Latin word Aditus, an
entry; passage or approach to the
mine.
ATTAL, or ATTLE. Waste; the débris
formed by the dressing of ores.
waste of the mine.
ATTAL-SARSEN, or SARACEN.
The
The waste
or remains of the stranger; sometimes
called "Jews' leavings."
BACK. The roof of a level.
BACK OF A LODE. The portion between a
level driven on the lode and the surface.
BANGERTS. A coarse sort of stopping used
to hold up the earth.
BAR. A grip or twitch in a vein or pipe,
"striking it dead" (Hooson).
BARMASTER. An officer in Derbyshire kept
at the charge of the lord; "he is servant
to both lord and miner-to the lord in
gathering his duty or dues, and to the
miner to measure his ore, seeing equal
and just measure, laying out mineral
ways," &c. &c.
BARMOTE COURT. A court held in Derby-
shire twice in the year only, established
by a decree in Edward III.'s time.
BATCH. A batch of tin signifies a heap, or
"parcel of tin."
BELLAND. A distemper lead-miners are
subject to ; a kind of lead-poisoning.
BELLY. A swelling mass of ore in the lode.
BEU or BEUHEYL. A "living stream"; the
productive portion of a tin stream.
BING ORE. The largest and best kind of
lead ore.
BINGSTEAD. The place where bing ore is
dressed.
BLACK TIN. Oxide of tin; Cassiterite. Tin
ore triturated, dressed, and rendered
clean for smelting.
BLANCH. A piece of ore found isolated in
the hard rock.
BOKE. A small run in pipes, found connect-
ing the ore, running through the vein.
BOLES. In Derbyshire, old lead works. Places
on high ground and exposed to the
wind, where smeiting has been carried on.
BOOSE. That part of the vein which affords
round lead ore.
BOOTIT. A term used by Derbyshire miners
for loss-"last reckoning I bootit it
thirty."
BORER. A piece of round iron about 20
inches long, with a steel point, which is
driven into the rock to make holes for
the purpose of blasting.
BOUT. A word used in measuring lead ore;
a long bout is 24 dishes, a short bout is
12 dishes.
BRACE. A platform on which the miners
stand to work the tackle.
BRASSIL. A hard substance resembling
brass in colour; often applied to pyritic
ores.
BRAZEN DISH. The gauge, or standard, used
in the Low Peak, Derbyshire, made of
brass, chained to a certain place. The
miners measure their lead ore in this dish.
BREAKING. A method of breaking poor or
dredge ore by hand with flat irons, called
breaking hammers.
BROOD. Any heterogeneous mixture with
tin or copper ore, as mundic (iron py-
rites) or black-jack (blende).
BUDDLE. A long horizontal box into which
the pulverised tin-stuff is deposited by a
continuous stream of water, after having
passed over the upper part. A circular,
and sometimes inclined, table upon which
ores are more or less freed from vein-
stuff or waste.
BUDDLE WORK. Dressed, and partly-dressed
ore obtained from the buddle.
BUNNINGS. In Derbyshire, stages of wood
across the mine; a roofing.
BURK. A hard knot or lump in the vein.
CALLEN, or KALLEN. A term used in St.
Just to signify iron, especially where a
lode is abundant in a soft iron ochre-as
Huel Boys Callen, Grouse Callen Lode.
CANNY. Many of our lodes contain beds of
carbonate of lime and fluor-spar, alias
"cann'” the lode is then called canny.
CARBONA. A treasure-house. A large flat
deposit of tin ore. See p. 406.
CASED TIN. That which is reframed by a
gentle current of water, and prevented
from running off the frame or table.
908
GLOSSARY OF TERMS.
CASTAWAYS. Sterile veinstone.
CAVERS. People who go from mine to mine
picking up small bits of lead ore.
CLAY IRON. An iron tool used for driving
through clay, which in some very hol-
low ground it is necessary to use, to
facilitate the blasting of the rock; the
charge being in that case put into the
hole when the clay-iron is withdrawn.
COARSE. When a lode, or the stuff from it,
is not rich, the metal being only thinly
disseminated throughout, it is called a
<< coose lode," or coose stuff." Dradgy
has the same meaning.
COBBED ORE. Ore broken from the vein-
stone by means of a small hammer.
CôE. A small cabin built over the shaft, of
clods or boards, to keep the shaft dry.
CÖFFER. Cöfar, Kopher, a chest in which
the stuff is pulverised by means of stamp
heads.
COFFIN, or KOFFENS. This applies to old
workings at the surface, and what would
be a gunnis underground is at surface
called a coffin. It applies to "old work-
ings" on the course of lodes, which are
generally the result of the ancients hav-
ing carried away the soft ground, viz.
the gozzany, flukany, or slovany parts
of the lode, easily broken down, and
then dressed by them for the tin found
in it.
COPE, or COPE MONEY.
In Derbyshire, the
price per ton of lead ore.
COPER. A Derbyshire miner.
COSTEANING (COTHAS-STEAN).
Fallen or
dropped tin. Searching for tinstones.
COSTENING PITS. Pits dug in search for tin.
COUNTRY, THE. The rocks in which the
mineral vein lies.
CREAZE. The "work" or tin in the middle
part of the buddle, which is divided into
the head or fore part of the buddle, the
creaze or middle, and the tail or last,
sometimes called the hind creaze.
CROP.
Ore, or tin, of the first quality, after it
is dressed or cleansed for smelting.
CROSS COURSES. Veins not metalliferous,
usually at right angles to the lode.
CROSS CUTS. Horizontal galleries not driven
in the productive vein.
DACKER OF WIND. Foul air in a mine.
"Warm and close foggy weather is bad,
and when pease was in blossom then
was the worst time for wind in the
mines of all the year" (Hooson).
DAMP. As fire-damp, choke-damp, ground-
damp, &c. Light carburetted hydrogen,
carbonic acid, or other gases injurious
to life.
DAY. The light seen at the top of a shaft.
DEAD. A place where there is no ore.
DILLUEING. A method of washing, or finish-
ing the dressing of tin, copper, or lead
ore on very fine hair sieves.
DILLUER. A horse-hair sieve.
DIPPAS. Little pits in a mine.
DOUK or DOUKE. Probably derived from
the Saxon deagan, to knead or mix with
water. A soft substance found in veins.
DRADGE. Pulverised refuse.
DRADGY. A dradgy lode signified a coarse
lode, or rather a lode or stone through
which the ore is so thinly disseminated
as to be scarcely worth the expense of
dressing. Such lode, ore-stuff, or stone
is called "dradgy."
DRESSER. Any person who superintends the
boys and girls on the dressing-floors.
DRIFTS OPENING. Horizontal openings or
adits in veins.
DRIVINGS. All excavations horizontally.
DRUSES. Hollow cavities in the lode.
EQUIVALENTS. Grains of ore or vein-stuff of
varying diameters and density, which
fall through water at an equal rate of
velocity.
ESTOVERS. "It has been held that when
the commoners have a customary right
to dig gravel, or take Estovers, the lord
had no right to approve or inclose."
("Law of Mines and Minerals," by Wm.
Bainbridge.)
EYE OF A SHAFT. The very beginning of a
pit.
FADDOM. A fathom, 6 feet, commonly used
as a measure by miners.
FAMP (Cumberland). Decomposed Lime-
stone, or in other districts a silicious
bed composed of very fine particles.
FANGE. A place left, as the miners drive
along the drift, to carry the air freely
onward.
FAUSTEDS. The waste left in the sieve
separated from the last of the ore.
FIERY DRAKE, or BURNING DRAKE.
A
meteoric appearance, supposed to indi-
cate the place of a lead lode—a super-
stition nearly exploded.
FINE RAGGINGS. Pieces of ore deposited at
the bottom of a sieve.
FLATS. Decomposed beds of Limestone.
Flat or Flot. Hooson, a Derbyshire miner,
in 1747, describes them thus: "It is
neither vein-pipe, rake, nor scrin, but
GLOSSARY OF TERMS.
a place that hath both length, breadth,
and thickness, but all uncertain.”
FLUKAN. Generally a soft greasy substance,
sometimes running on the lode and
sometimes in, and under the lode. When
it runs in the lode it is called the pith
(pronounced peath) of the lode.
FOACH.
A narrow level is called a "Foach-
ing little level." When a miner has not
obtained what he considers a full price
for his contract he would be likely to
say, ""Twill do 'pon a foach," viz. it will
do on a push. Foach is nearly synony-
mous with another old Cornish word,
"Pock," or "Pokkin," to push.
FODDER. A fother or futher, (Teut.) Fuder,
a burthen, and this from futixen, to
carry, and from the Latin vehere quod,
as much as can be carried in one cart
("Doomsday, Mines in Derbyshire ").
At the time of the great survey, 20th
William the Conqueror, in "Dooms-
day," under Derbyshire, and in the
parishes in the Peak, among the rents is
mentioned the rent of lead, and the
return is thus: "Et quintæ plaustras
plumbi, et de quinquaginta tatulis." The
five plaustras are five cart-loads, and
the other are fifty sheets of lead. Then
the duty was paid and delivered in
measure by the load, and the load is
still preserved in the ore. In ancient
times the fodder was determined by
measure; latterly it is estimated by
weight, and the fodder or wey of lead
is said to contain eight pigs or sixteen
pieces, and every pig, or two pieces,
23 or 24 stone. A fodder of lead in
London is 2,184 lbs. weight; in Bristol,
2,240 lbs. weight: in Hull, 2,340 lbs.
weight; in Newcastle-upon-Tyne, 2,352
lbs. weight; in Chester and Liverpool,
2,400 lbs. weight; in Stockton, 2,464
lbs. weight; in Derby, 2,520 lbs. weight.
FOUNDER. The first shaft sunk upon a vein.
From this the miner possesses, and lays
out his ground.
FRAME OF RACK. A table composed of
boards slightly inclined, over which
runs a small stream of water to wash off
waste from slime tin.
FREEING A MEAR.
The first dish of ore is
given to the lord of the mine, which
frees the miner.
FUSE. A hollow tube for ignition made of
a fine case of yarn, filled with gunpowder
and pitched on the outside to prevent
wet reaching the core, viz. the gun-
powder.
909
GAD. A steel wedge for separating the rock.
GANGUE. Mineral associated with ore.
GARDE. Small pryany matter, coarse sand
separated in dressing tin.
GHURR, THURR, or "THE MOTHER OF
METALS." The matter or substance
which in time is supposed to ripen, and
become real ore. Glauber the alchemist
(from whom we get Glauber's salts (sul-
phate of soda) tells us "that in Ger-
many the miners know when the ores
are not grown to perfection, and usually
say they are come too soon; and shut
up the mine again for some years till
it is ripened and grown to perfection."
GINGING (Derbyshire). Timbering a shaft.
GIRDLE BEDS. Thin beds of a hard and
Beds.
compact kind of Limestone.
Gozzan. Soft, ferruginous part of the lode,
generally found near the surface, and,
when of favourable appearance, highly
valued by the miner, as ominous of good
results.
GRAIN TIN. Oxide of tin in the form of
grains or pebbles.
GRATE (STAMP). An iron or copper plate
thickly punched with small holes.
GRIDDLE. A large wire sieve for sifting ore.
GRIZZLEY. See Slide.
GROOVE. The mine or work that a man is
employed in-"He is gone to the
groove." Miners in Derbyshire were
commonly called "groovers."
GROUP OF GRAINS. Grains of ore-stuff of
different dimensions which may exist
between two specified dimensions of
grains.
GRUFFS. Names given to old mines on the
Mendip Hills.
GRUMMET. Rope laid into a ring. Rope
grummets are used as wads in firing
shots.
GUIDES (St. Just). Cross veins.
GUNNIS. This signifies the horizontal ex-
cavation on a lode. The common size
adopted for a level is about 7 feet by
3 feet, but from the peculiar nature of
the lode it is found an advantage to
the miner to break it down much wider
and higher than that. The miner would
then say,
"We are foased (forced) to
work thicky (that) end with a laerge
gunniz."
HALVANS. Sand or waste resulting from the
dressing of ore. These may be con-
sidered as the general leavings of the
mine, and consist of small particles of
ore in the burrows, precipitates into the
910
GLOSSARY OF TERMS.
dressing-floors, &c. Halvans, after being | JOINT. A parting in the rock, rider, or ore,
sett on tribute to those tributers called
"halvaners" by the adventurers, are
frequently resett by the lords (or their
agents), after the workings have been
abandoned.
HAZLE. A Saxon word, denoting a Sand-
stone that is mined with difficulty.
HEADS. The upper or concentrated portion
of ore lodged on a buddle or frame.
HEAVE. When the lode is lost in the end of
the level, by a cross course, flukan,
gozzan, or other cause, the lode is said
to be "hove" or heaved.
HILLOCK. A heap of sterile vein-stuff or
stone.
HORSE IN THE LODE. A dead or worthless
part in the lode; generally composed of
fragments of the strata through which
the lode passes, which invariably divides
the lode.
HOUSE OF WATER.
An abandoned mine
filled with water-therefore dangerous to
all adjoining mines.
HUEL. The old and correct Cornish spell-
ing of Wheal, a mine.
HULKING. Hulking the lode means taking
down (removing) the soft part of the
lode previous to taking away the harder
parts thereof, which is done with con-
siderably less trouble after the miner has
gone in " with his hulk. "I've known
miners hulk their lode the whole extent
of their 'stent' (bargain), viz. several
fathoms, before breaking any of the
metalliferous part of the lode down."
HUSHING. Allowing a stream of water to
flow over and carry away the soil, so
that a lead lode may be exposed if it
exists.
ง
HUTTRILL. Any hard pannel in a vein.
JAUM. A joint of clay running across a
vein.
JIGGER WORK. Dressed and partly-dressed
ore obtained from jiggers.
JIGGING. This applies to the dradgy stuff
which, being first reduced to several
sizes smaller than backed stuff (chiefly
by a crusher), is washed in sieves sus-
pended in water, the action of jig-
ging (viz. shaking) having caused the
metallic (consequently the heaviest) par-
ticles to precipitate, the skimpings, are
scraped off and thrown away, the ore
being taken care of. A method of
dressing small ore by a pulsating motion,
imparted either to a sieve or to stuff
lodged in a sieve.
or any other substance in the mines.
JOUPH-HOLES (Derbyshire). Hollows in the
vein.
KAPLE or CAPLE. The Caples of the lode
imply the walls and the effects of the
walls of the lode in the general strata.
It is not unfrequent that a miner will have
a poor lode, but find sufficient tin-stuff
in the Caples thereof to remunerate him.
KECKLE - MECKLE. The poorest kinds of
lead mines.
KIBBLES. Buckets in which the stuff is
brought to the surface.
KIEVE. A vat or large iron-bound tub for
washing ores.
KITTING. Thieving in combination.
A
takes a pitch wherein he contracts to
give the adventurers (owners) of the mine
6s. 8d. out of every 20s. worth of ore he
may be enabled to raise during the term
of his take and the limits of his pitch.
B has a pitch subject to payment of 15s.
out of 20s. A and B agree to "kit:"
viz. B puts or allows A to put a part of
B's ore to A's heap, consequently B's
ore, which is subject to a tribute of 15s.
to the adventurers, pays thereby but
6s. 8d. There are other modes of cheat
ing the adventurers by miners mixing
their ores, and sometimes by stealing
from heaps not their own, and carrying
to their own heap. All these thefts
are called "kitting.
KNOCKER. "The miners say that the
Knocker is some being that inhabits in
the concaves and hollows of the Earth,
and that it is thus kind to some men of
suitable temper, and directs them to the
ore by such its knocking" (Hooson).
KNOCKING-BUCKER. A tool cut out of a
strong flat bar for breaking ore or any-
thing that is mixed with ore or fausteds.
LACES, STOOPS, or NICKS. Lines cut with
the point of a pick on Slickensides.
LATHS. In driving through very soft ground
or clearing levels in which there is a
great deal of loose stuff, the miners
(having first placed pieces of stout timber
called "durns") drive planks of stout
timber through the stuff; these planks
are called Laths.
LAUNDER.
A trough of deal boards for con-
veying water, or slime water, from one
point to another.
LEADS. Small fractures in the rocks, fre-
quently connected with veins.
GLOSSARY OF TERMS.
LEAP. A term used in mining to express
the apparent movement of the lode; as
when the vein is thrown from its per-
pendicular course, at once, into the side.
LEAVINGS. Leavings rarely applies to copper
dressing, but to tin, where the small
quantities of that mineral which has
mixed with the general refuse in slime
or row become (agreeably to the estab-
lished contract custom between the
tributers and the owners of the stamps)
the property of the latter as part pay-
ment for the use of the said stamps.
LEPPEY. Work which is easy, "soft, kind,
and winable, without any hardship, as
boring, cutting, blasting," &c.
LEVELS. Horizontal galleries in a mine.
LIFTER. The stem of iron attached to the
stamp-head.
LIMP. A tool for separating ore.
LOAD OF ORE. In the customary Liberties of
Derbyshire ore is never weighed. Nine
dishes-which hold exactly eight quarts
of water-make a load.
LOCH HOLES. Cavities, vughs.
LODES. All metalliferous veins.
LODE SLOVAN. When miners bring up a
drain on the course of a lode, particu-
larly in a low marshy place, they say,
"We are bringing up a lode slovan 'pon
the lode." This is done for the two-
fold reason of developing the appear-
ances in the lode shallow, as well as to
form a drain for the lode when it has
been thus traced into higher ground.
LOOBS. Tin slime or sludge of the after-
leavings.
LORD'S-MEAR. The portion which belongs
to the lord.
LOUGHS. Derbyshire levels.
MALLET. A hammer used for driving the
borer into the rock.
(6
MATRIX. Mineral associated with ore.
MEAR OF GROUND. The length of 29 yards,
in Derbyshire, kept by placing a small
'stoice "
stows" at the end of it.
MEAR STAKE. A large stake driven in the
ground at the mear's end.
MIDDLES. Partly concentrated ore, and
or
gangue, forming the middle portion de-
posited on a buddle or table.
MINERAL. "The term may, in the most en-
larged sense, be described as comprising
every component part of the solid body
of the Earth, both external and internal,
which is destitute of, and incapable of
supporting, animal or vegetable life. In
this view it will embrace as well the
911
loftiest pinnacle of the rocky mountain.
as the most hidden matter beneath the
surface of the globe, the hardest and the
softest of fossil substances, from the
diamond to the sand beneath our feet,
the heaviest metal and the lightest tufa."
("The Law of Mines and Minerals,"
by Wm. Bainbridge.)
MINERAL TIME. Eight hours' space in Der-
byshire and in some other districts.
MOCK ORE. A false kind of mineral, some-
times applied to zinc ore (black-jack).
NIPPER. A tool used by the lander for
seizing the kibble, and upsetting it into
the wheel-barrow.
NITTINGS. The ore that remains in the
sieve in washing of Smitham which is
rounder than the Smitham.
OLD MAN. "The gear that has been stirred,
or cut, before by somebody, which can
never happen but in old works, or in old
ventures" (Hooson).
PACKING. A final dressing of tin or copper
ore in a kieve or vat with water, after
stirring the water and striking the sides
of the kieve.
PARCEL. A parcel of ore is a pile or heap of
copper or lead ore dressed for sale.
PASS. An irregular excavation (generally
bored by tributers) from level to level,
and then used as a means of communi-
cation and ventilation, but chiefly for
throwing ores or refuse through.
99
The bottom of the hopper placed
behind the stamps coffer.
PEE. Two veins crossing each other ob-
liquely.
PILE OF ORE. A heap of ore, a parcel of
ore, and sometimes a dole of ore.
PITH. The soft part of the lode. In some
districts (or rather say in some lodes)
the pith consists of steatite-in others
soft calcareous spar-in others flukan,
and in others a limey uncrystalline
substance of a great variety of appear-
ances. The peath is a great advantage
to the miner in hulking the lode.
PLATE. Black Shale, a slaty rock.
POST. Limestone strata divided horizontally
with very thin beds of shale.
POWDERED ORE. When a vein is spotted
with ore or stones of ore, or when ore is
disseminated with vein-stuff, it is desig-
nated "powdered or dredged ore."
PRIAN. White lithomarge.
PRILL. A rich part of a stone of ore—also
912
GLOSSARY OF TERMS.
the result of an assayer's trial of a
sample. A miner who attempts to cheat
the assay master is said to have "prill'd
the sample" by unfairly slipping in a
bit of superior ore with the sample to
be tried.
PRILL ORE. Solid ore. Pieces and large
grains of solid dressed ore.
PUPPET-HEAD. The elevated bearers of the
truckles, alias sheaves, over which the
rope or chain passes into the shaft.
QUARRY. "A quarry is an open excavation
where the works are visible at the sur-
face." ("The Law of Mines and Mine-
rals," by Wm. Bainbridge.)
QUEERY. When the lode or rock on which
the miner is driving partakes of the
character of quarry stone, viz. in de-
tached lumps by natural divisions, it
is called queery ground, and is fre-
quently worked with crowbars and such-
like levers instead of being blasted or
gadded. A "queer of ground" means
a detached rock.
RACHILL. Small loose stones that are usu-
ally found on the top of the rock, form-
ing as the depth increased into the
nature of beds.
RAFF WHEEL. A wheel with buckets inside
of its periphery.
RAGGINGS. Small pieces of ore attached to
veinstone.
RECK or RACK. A wooden table (placed a
little on the slant) over which slime tin
is washed by women.
RIBB. Lines of ore in the veins.
RIDDLE. A large iron sieve for sifting ore
-a coarse sieve.
RIDER.
A stone running in a vein by which
the body of it is divided.
RIFFLE. A ledge placed across a buddle or
table, sometimes a bar made across a
table.
RISE. This is the same meaning as Stope,
or excavation in the back of a level.
Frequently when a miner who has just
left his work is asked where he has been,
his reply is, "I belong (viz. I work) up
in the rise." All excavations upwards.
ROUGHS or Rows. Tinstone enriched to
afford 65 to 70 per cent. of oxide of tin
is termed crop." Poorer and larger
grain-stuff containing a variable per-
centage of tin is called Roughs or Rows.
RUTE. A small thread of ore, same as
"Scrin."
SAMPLE. Taking certain portions of tin,
copper, lead, blende, or other ores for
assay purposes.
SARCENS. Strangers. See Attal-Sarsen.
SARVEE. "The country people did make them
pay sarvee for every particular thing."
SCALL. Loose ground; foliated ground is
frequently called scally ground by
miners.
SCOVANS. Small veins, so called in St. Just.
SCOVANY LODE. A lode in which there is no
gozzan, flukan, pith, or other advantage
for working, is called a "scovany lode."
Frequently, although small particles of
gozzan are found in lodes, they are called
by the miners "scovany," but in nine-
teen cases out of twenty these have been
composed of peach, mundic, hard caple,
and killas.
SCRIN. The least or smallest kind of vein.
SCROWL. In many of our (Cornish) mining
districts a thin (sometimes calcareous
and sometimes silicious) substance struck
against the wall of the lode, the miner
calls the "scrowl" of the lode;—if of
good appearance it is considered by him
a favourable omen.
SEVERALL. A name formerly given to en-
closed lands. "In Severall no man
can search for Tynne, without leave first
obtained from the Lorde of the soile;
who when any mine is found, may work
it wholly himself, or associate partners,
or set it out at a farme certain, or leave
it unwrought at his pleasure." (Carew's
"Survey of Cornwall," ed. 1769.)
SHAKES. Caverns in lead mines.
SHAMMELS. Plots or stages fixed in an open
working.
SHOAD (from Shutter). To pour forth.
SHODES (from Shutten, to put forth). Scat-
tered stones found in streams.
SHOOTING NEEDLE. A copper bar with iron
head for driving through the tamping
and charge to admit the rush, quill, or
fuse, previously to blasting a hole.
SIEVE MESH. The length of the side of a
hole in a sieve.
SIEVE
Sieve RagginGS. Pieces of ore deposited
at the bottom of a sieve.
SILL. A piece of wood placed across a
drift, probably derived from the Saxon
syl, a threshold.
SINK. An excavation under a level, viz.
adit or other level.
SKIMPINGS. Worthless sand obtained from
the jigger or tozing kieve. The refuse
taken from the top of the sieve in jig-
ging.
GLOSSARY OF TERMS.
SLIDE. A fixed incline composed of bars of
iron set at given distances apart.
SLIME ORE.
ORE. Finely pulverised mineral
mixed with water in the state of slime
or mud.
SLIP JOINT. A dislocation in a slanting
direction.
SLOVAN. The cropping out or back of the
lode. This generally applies to the ap-
pearance of a lode in a marshy place.
N.B.-Cropping out is a Welsh, also
East and North of England, term—but
is never used in Cornwall.
SLUG. A loop formed at the end of a
rope through which a miner passes his
leg previously to descending an old shaft
or working. The other end of the rope,
also a signal rope, being left in the hands
of the miners at the surface, who lower
their comrade and attend to the signals
he may communicate during his recon-
noitre. A slug is also in common use
in a mine by miners in lowering their
comrades into old workings, &c.
SMALL ORE. Copper, lead and blende ore
dressed to a small size.
SMALL TIN. Tin dressed from slimes.
SMALLS. Gangue and ore of a small size.
SMITHAM. The smallest of the
ore that
goes through the wire bottom of the
sieve.
SNOFF or SNUFF. A bit of paper about
3 inches long, prepared with grease
and gunpowder and placed across the
rush when fuse was not used; viz. one
kind being fastened to the rock with a
bit of clay, and the other end having
passed about 2 inches over the rush;
this end was then ignited, and the miner
ran to a place of safety to wait the
effect of the "snoff" communicating to
the charged rush and thence to the
charge.
SOLLAR. A chamber (also
A chamber (also resting-place)
generally about 10 fathoms apart in the
footway shaft.
SPALL.
To spall, or to break, large stones to
about the size of road metal.
STALCH. A mass of ore left uncut when
other work has been done around it.
STALL. Platform on which ores or deads
are deposited; sometimes a reserve place
for deads, thereby saving the expense of
drawing it to surface; this would only
occur in old mines where stalls are
frequently placed in old excavations.
STENT. An abbreviation of extent, and
means the limits on which the pitch or
bargain is taken-Rubble, waste.
913
STEWARD. The person set by the masters
of the mine in Derbyshire to oversee
the work and the men employed
therein; who cut, sink, and drive, as
he directs.
STICKING SCRINS. Small veins that do not
afford shoulder room.
STOOP (Derbyshire). Forefield of a mine.
STOPE. That part of a vein which is always
cut "toploose."
STOPING. Stoping the bottom of a level
applies to sinkings already explained,
and stoping the back of a level sig-
nifies "rising," which see.
STOWSE (Derbyshire). Drawing apparatus.
STRAKE, or TYE. A kind of narrow buddle
used with a quick current of water, for
washing the roughest part of stamped
tin (called "row"). Also used for dress-
ing crushed lead stuff.
STRECK.
Signal word for the whim or tackle
to be retrograded.
STUFF. Ore associated with gangue.
SUMPS. Places sunk and drawn under
ground below the shaft foot.
SUN VEIN. South veins, or veins running
south, or veins discovered on the south
side of a hill. Common in the northern
counties.
SWEEPS. Buddle brushes or pieces of cloth
for sweeping the smooth surface of
buddle work.
TACK NOTE. Lease of tack, for any
definite term less than a year, of
any dwelling-house or tenement, or part
of a dwelling-house or tenement, at a
rent not exceeding the rate of £10
per annum. Agreement for or with
respect to the letting of lands, or for a
sett of a mine, &c., for term not exceed-
ing thirty-five years, liable to lease duty.
TACKLE or TAKLE. A windlass.
TAILS. The lower portion of stuff lodged
on a table or buddle.
TAMPING. The gravel, clay, &c., driven
down on the gunpowder.
TAPISHED. When damps break in “at un-
awares," and the miner just escapes with
his life, he is said to be "tapished."
TAPPET. A boss or disc of iron fixed around
the stem of a stamp-head.
TICK HOLES (Derbyshire). Drusey cavities.
TIGHT. This is different from hard. When
a miner is driving an end at the rate of
30s. to 50s. per fathom, he frequently
breaks the ground without the assist-
ance of gunpowder, but although the
end when taken might be heady or
914
GLOSSARY OF TERMS.
queery, or fair or sparry, yet from
change of strata, or other cause, the
end frequently becomes so short and
crumbly in its nature, that blasting
avails scarcely anything, and the pick
and gad are useless; the end is then
called tight.
TIN STONE. Stone or gangue enclosing
minute grains of oxide of tin.
TIN STUFF. Tin ore obtained from a tin
lode.
TONGUE. A piece of iron or steel projecting
from the stem of a stamp-head.
TRELOOBING. Stirring and working the
loobs or slimy earth of tin, in a slime
pit, that the mud may partly wash off
with the water and the ore settle at
bottom.
TROMMEL. A cylindrical or drum-shaped
sieve.
TURBARY. "A right of turbary is confined
to such a quantity of land as is sufficient
for the house to which the common is
appendant." ("Law of Mines and
Minerals," by Wn. Bainbridge.)
TURBERY. A turf-field.
TURN-HOUSE. Altering the direction of the
workings.
TWITCH. The sides of a vein coming closer
together.
TYE. The point where two veins seem to
cross each other or where two pipes
cross obliquely.
""
The same as strake, but worked with
a smaller stream of water.
TYTн. An ancient custom or duty which
miners gave to the priests.
In my
time (1747) I have known it taken every
twentieth dish" (Hooson).
UNDERLIER. A shaft having a steep incli-
nation.
VEINIFEROUS ORE. Ore associated with
gangue ore or mineral.
VEIN SKIRTS (Derbyshire). The walls of a
lode.
VEIN STUFF. Ore associated with gangue.
VESTRY OF BOWSE. A very productive part
of the vein. See Carbona.
VOLUMETRIC GRAINS. Grains of a definite
size or diameter, but of a variable
density, which fall through water at
different rates of velocity.
VUG.
A hollow lode is called a vuggy lode.
It is also frequently used by miners for
cavern-which they call a great vug,”
or vugga. If you ask a St. Agnes miner
("
""
the meaning of the celebrated cavern
called the "Seal Hole," he would say,
Why, 'tes a large vugga washed in by
the sea 'pon the coose of a lode."
(6
WARGEARE. A general name in Derbyshire
for whatsoever belongs to the mine.
WASTRELL. Waste or common land.
"An action of trover was brought for
copper ore raised upon Towan, in the
parish of St. Agnes, Cornwall, by the
lessees of the Lord of the Manor, who
was entitled to the toll of tin in all the
lands, both customary and freehold, and
also in the wastrell or common called
Towan Common." ("The Law of
Mines and Minerals," by Wm. Bain-
bridge.)
"In wastrell it is lawfull for any man
to make triall of his fortune, pro-
vided that he acknowledge the Lordes.
right, by sharing out with him a certain
part, which they call toll. . . . . The
wastrell works are reckoned amongst
chattels, and may pass by word or will."
(Carew's "Survey of Cornwall," ed.
1769.)
WHIM. A rotary machine worked by horses
or by steam for drawing stuff from the
mine through the shaft.
WHISKETS. Shallow oval baskets.
WHITE TIN. The metal produced by the
smelter.
WHITTS. Partially dressed tin-stuff. Applied
especially to dressed tin from the stamps
floors ready for the burning - house,
therefore still retaining the sulphur ores
which give the mass a white metallic
appearance. These are removed by
burning.
WHOLES. Such ground as has never been
cut.
WINZE. A shaft sunk from level to level for
ventilation and for dividing tribute
ground.
ZAWN. In St. Just, a cavern.
ZIGHYR. A slow stream of water issuing
from a crack.
ZUE, ZUEING, or DEZUING. The same as
hulking a lode, viz. removing the soft
side for facilitating the breaking down
the harder part thereof. If a miner is
asked, "How is your lode looking?"
he will often reply, "I don't know, for
I have been zueing (sometimes they
say dezuing) the lode ever since I saw
you last.”
INDEX.
iron ores, 797
lead mines, 458
mineral veins, 456
ABALITES, imports into, 2
Abbadine, Mr., cut a tunnel through
Alderley Edge, 258
Abercarne Colliery, electric blasting, 533
Abergele, Roman remains at, 39
Aberystwith district, bare of veins, 253
Account, Clifford Amalgamated, 1863, 432
Adit described by Carew, 65
cutting of an, 657
Alston Moor, character of, 399
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copper mines on, 828
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Great Gwennap, 425
level, driving of, 566
""
Ærated barytes, 483
Æris metalla, Roman bronze, 41
Agamemnon's breastplate, 3
Agar Wheal, accident at, 592
"Aggravii Venetiani," a pamphlet, 56
Agricola Georgius, "De Re Metallica,” 94
on the divining rod, 95
""
""
on iron mines and collieries, 43
on mining (1546), 83
Air in levels of Clifford Amalgamated mines,
""
376
pipes and reservoirs, 512
,, temperature of, in Comstock Level, 375
volume of, passing through fireplace, 644
Airy, Sir George, on the density of the Earth,
384
Alabaster in Derbyshire, 233
Alderley Edge, description of, 257
""
""
""
""
""
copper and lead at, 162
copper ore of, 257
size and cost of levels on, 579
thickness of rocks on, 246
Sulphur vein, 312
Aluminous brown iron ore, 811
""
iron ores of Antrim, 807
Amber, sought for by the Tyrians, 9
Analyses of rocks, 225
Analysis of tin ore, 787
Ancient smelting of tin, 71
Anemometer, Biram's, 615
Anglesea, copper, early production of, in, 827
""
""
""
""
""
""
""
mines, 122, 444
ores, letter on, 105
faults and copper lodes, 324
mines, produce of, 1778, &c., 448
Roman remains found in, 37
Sir A. C. Ramsey on, 265
subjected to Rome, 25
Animals, blood of, silver diffused in, 362
Anne, Queen, tin trade in her time, 818
Antimony produced in Cornwall, 184
in Scotland, 275
""
Anzin Collieries, boring machine, 541
Arago, M., on temperature of well at Grenelle,
579
Ardtully-Kenmare, a copper mine, 279
Stanley of, Lord, discovers slags Argall's jigger, 760
on Alderley Edge, 261
Alesia (Arras), the metallurgy of, 22
Argillaceous carbonates of iron, 807, 809
greenstone, 214
Alexandria, magical transmutation of tin Ariconicum (Western), site of Roman iron-
going to, 45
Allan, T., Professor, describes Dufton, 462
Allen, Mr., "History of Liskeard," 15
Allendale mines, 467
""
and Weardale lead ores from 1845
to 1881 (Appendix), 900
Allenheads mine, 466
Allihies mine, 279
Alluvia, Farey explains, 233
Alport mines, Derbyshire, shaft in, 567
Alston, contents of mineral veins, 456
works, 44
Armagh, lead mine in Derrynoon, 281
Arrastre, 742
Arrian, the Periplus of, 2
| Arsenic in coal, 365
Artesian water, temperature of, 379
Ashburton mines, 230
Assay of ores, 701
Association, British, the resolution of, 815
for the tin trade (note), 81
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""
of minerals, 495
3 N
916
INDEX.
"Astragal" knuckle-bone shape of slab of Basset, Sir Francis, grants a sett of Roskear
tin, r9
Athelstane's invasion of Cornwall, 45
Atkinson, Mr., of London, describes the
silver ore of Hilderston, 164
""
land, 172
account of gold mines in Scot-
Attal-Saracen or Sarsen, I
Attle cemented by oxide of iron, 372
Auriferous veins at Clogau carry lead, 265
""
vein at Crossgill, 313
Australian tin, 820, 821
""
stamps, 733
Automatic boring machines, 524
mine, 112
Batavia, sale of tin in, 821
Bath-brick laminated by electricity, 387
Bath, Earl of, Queen Elizabeth presents a
silver cup to, 128
Bathgate, lead mine at, 270
Baumer, J. G., on veins, 330
Bauxite, 807, 809
Bayley, Sir Nicholas, grants a lease of Parys
mine, 444
Beacon, The, St. Agnes, 204
Beare, Mr., writes "Bailiff of Blackmore,"
187
Average fall of rain, and discharge by adit, "Bearing measures," or "feeding ground"
621
Avienus's "Ora Maritima," II
Awboys lode, Balleswidden mine, 349
"BACKBONE of the Earth," Sopwith on,
457
"Bailiff of Blackmore " (note), 49
""
""
Lostwithiel, 167
on gold found near
Bal or ball, origin of the term, 83
Balcarres MSS., gives weight of lead shipped,
163
Balducci, Pegolotti, original MS. by, 47
on prices of tin in Cornwall, 47
""
""
""
of the miners, 238
Bearing of a vein, 286
Beauchamp, Mr., covenants to sell copper
ore, 827
Beaumont, J., on Harptree Cavern, 31
""
on lead mines and caverns in
the Mendips, 137, 138
Beaumont's camel, 519
""
Elie de, Mountain System,
297
Beckman on Bohemian tin mines, 45
on the ore Luna Calamine, 132
on tin and tinning, 42
""
"9
Becquerel, M., on influence of electricity, 385
produces crystals by electri-
city, 385
""
on slow chemical changes, 495
on the tin raised in Cornwall, 817 Bedford, John, Duke of, had a great gold and
Baldue mine, Roman workings at, 23
Ballacorkish, boring at, 527
mine, boring in, 543
Ballinvalley stream, gold in, 482
Balleswidden mine, St. Just, 349
Ballycorus lead mine, 280, 471
Ballygaham, copper ore sold, 277
Ballyhickey mine, co. Clare, 282
Ballymurtagh, copper ore sold, 277
""
mine, 475
Balnoon mine, disseminated tin, 354
Balwarth, or "Old mine," in Wendron, 411
Bampton, antimony found near, 230
Banca tin, 821
Bancks, Sir Joseph, a lead miner, 145
Bargains, partnership, miners', 585
Barmaster, Derbyshire, his powers, 140
Barmote, law of, 139
Barytes in Derbyshire, 235
in Shropshire, &c., 481
""
""
in Dufton mines, 481
in Scotland, 275
""
total produce of, 1881, 481
Basalt, Daubrée finds antimony in, 365
globular, vein filled with, 483
"
in Isle of Islay, 271
Basaltic rocks, Sopwith on (and note), 249
silver mine, 130
Bedil, definition of (note), 46
Beecher on formation of metals and minerals,
327
Beer Alston lead lodes, 303
Bejowans, in Sancreed, section of, 348
Bells commonly used in France and in
Britain, 45
Berehaven mine, 279
Berger, Dr., on filons de matin, 285
on the granite of Anglesea, 266
on joints in grauwacke, 225
""
"
on silver in Cornwall, 490
""
on tinn-wald, Isle of Man, 325
Bergman, Sir Tobern, "Physical Geography,"
calamine, 142
330
on extracting zinc from
Betsy Wheal, near Tavistock, re-opened, 130
Beuheyle, a living stream, 75
Billiton, tin obtained from, 821
Bing ore, variety of lead ore, 145
Bischoff, Prof. Gustavus, on chthonisothermal
lines, 383
""
water, 347
on infiltration of
INDEX.
917
Bischoff, Prof. Gustavus, on mineral changes, | Borlase, Dr. William, on discovery of tin ore,
496
494
""
on
substitution,
""
"
""
""
""
Bismuth found in Cornwall, 185
Black, Dr., on the saving of fuel, 113, 114
Black jack in Derbyshire, &c., 235, 320, 831
Blacklead, its properties, 180
Blackett, Sir Walter Calverley, improved the
working of Alston Moor mine, 150
Blanzy Collieries, compressed air used in
boring, 506
Blasting and charging bore holes, 548
""
""
by dynamite, 530
""
by electricity, 532
""
by gunpowder, 529
""
by nitro-glycerine, 529
Blende, origin of the term, 837
Bloomeries on High Furness, 175
Blowing-houses (small blast furnaces), 70
Blue John lode, 480
Blue stone (Carreglas) ore of Anglesea, 453
""
""
Wicklow, 454
Boase, H. S., Dr., on contemporaneous veins,
""
""
"",
""
""
""
419
discovers tin pyrites, 404
on Cornish Greenstone, 213
on hornblende Slate, 217
on porphyritic and calca-
reous Slates, 852
Mount's Bay, 13
on the submersion of the
Bohemia, manufacture of tin plate in, 60
producing tin, 7
""
Boilers, strength of, 646
Boiler, Trevithick's the elder, 117
Bolerion or Belerion, the Land's End, 4
Boles, ancient, known to have existed, 146
Bolster, The, St. Agnes, a trench and earth-
mound, 14
"Bonnet pieces" in gold, coined of Scotch
gold, 170
Bonze erecting steam engines, 112
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498
on dressing of ores, 689
on exploring the lode,
564
on lead mines, 130
on a "Living Stream,"
75
on mineral lodes, 285
on gold in St. Stephen's,
168
on "poder," 827
on shodes, 75
on shode-stones, 499
on steam engines in
Cornwall, III
of Redruth, introduces separating
cone buddle, 696
inclined buddle, 769
William Copeland, M.P., on bronze
dwellings in Cornwall, 24
spears, &c.,
16
on the cave
Bornhardt's frictional electric firing machine,
533
Borrowdale blacklead mine, 179
Botallack mines worked under sea, 80, 402
Botterright, John, comptroller of mines in
Devon and Cornwall, 134
Boulders in Derbyshire, 233
Boulton's, Mr., letter to Watt, 113
Bounder, the, a worker of bounds, 56
Bounder's part one-twelfth, 107
Bounding introduced, 51
Bounds, situation of, in St. Agnes, 53
Bournonite, ore of lead and antimony,
230
Boussingault on dissemination of ores, 361
Bowes, Mr., works mines at Wanlock Head,
172
Bradley Lonsdale on Swaledale lodes, 318
Brain, Mr. Blanch, radial system, 542
Borax Lake, mineral deposits on banks of, Brake jigger, 757
373
Bore-holes, rate of boring, table of, 546
Borer, beating of the, trying labour, 651
Borers for mines, 649
Boring by hand described, 503
""
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""
""
by machinery, cost of, 554
machines, progress of, 522
rock, machinery, particulars of sundry
results, 557
system, France and Belgium, 539
Borlase, Dr. William, Antiquities of Cornwall,
extracts from (note), 6
describes the "broil"
of a lode, 73
blowing-houses, 71
""
""
""
Brass wire, importation of, prohibited, 134
Brass works in England, 839
Bratt, Mr., erects a steam engine, 1812, 414
Breadth of lodes, 309
Brecciated lodes at Rosewarne, &c., 421
Breccia containing ore at Gourock and Los-
symouth, 360
Brecon Side lead mine, 466
Brendon Hills, iron ores of, 799
Bristol, lead ore found near, 232
British mining, future prospects of, 811
is it remunerative ? 868
Broile or bryle of a lode, 73, 499
Bronze and brass of the ancients, 5
early use of, 2
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3 N 2
918
INDEX.
Bronze image found in St. Just, 15
Brown's, Dr., observations on mines in Hun-
gary, 73
Brown-Willey, Granite, 202
Bruce, Dr., on the Roman Wall, 26
Brunton's concentrator, 769
Brymbo Main coal, lead in the, 441
Buckfastleigh, mines around, 230
Buckland and Conybeare quoted, 131
Buddle and table, 764
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centre head, 766
concave, 767
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hand, 765
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ring, 768
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the knife or impeller, 765
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Mr., of Newcastle, improves mine
ventilation, 611
Bullen Garden mine in 1778, 358
""
Campbell's, Dr., "Survey of Britain" quoted,
132
Cangi, the country of the, 29
Cantaro of tin, weight of, 47
Cape Cornwall boulders, 204
Capillary silver in Herland mine, 490
Capital invested in mines, 870
Captains, duties of (Carew), 64
Caradoc, or Bala beds, represented near
Crawford, 268
Carbona, term used in the New Testament, 406
a Syro-Chaldaic word (note), 407
in St. Ives Consols Mine, 405
Carboniferous formation, iron ore in, 796
Limestone, 235
""
""
berland, 251
Carclaze tin mine, 417
""
""
series of Northum-
plan and section of, 418
Bulmer, Sir Bevis, on Hilderston silver Cardiganshire, average depth of mines, 310
steam engines, III
mine, 163
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works Combe Martin
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mines, 129
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works lead mine in
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Lanark, 171
gives a cake of silver
to the City of Lon-
don, 129
Beer Ferris mines, 129
Bunches of Elvan in United mines, 210
Bushell, Thomas, case of (note), 153
secretary to Sir Francis Ba-
con, establishes a mint at
Aberystwith, 153, 154
worked mines in Cardigan-
shire, 153
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Butson Wheal, length of lode, 304
Byblus, the king of, founded Paphos, 3
CABLES for firing, 533
Cadmia found in Cyprus, 3
Caerhen, the ancient Conovium, 29
Calamine, an ore of zinc, 837
earth in the manufacture of brass, 839
found at Wrington, 131
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in Mendip Hills, 363
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used in making brass, 3
Calcining apparatus, 771
Caldbeck Fells copper mine, 121
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lead mine, 93
Calder, lead ore found at, 270
Californian stamps, 725, 733
Callon, "Lectures on Mining" quoted, 583
Cambrian rocks of Anglesea, 265
Camden's "Britannica
""
Britannica" on Keswick, 151
on copper at Keswick, 826
Caminche mine, Berehaven, 279
Campana, a bell first used in Campania, 45
character of county, 399
lead lodes, 320
lead ore since 1845 (Appen-
dix), 901
metalliferous district, 253
mining operations, 151
Carew on discovery of gold in Cornwall, 167
""
on thunder axes (celts), &c., 63
Carloose, Old, engine at, III
Carnarvonshire Mines, 262
Carn Brea Hill, 216
""
""
flat lode of, 407
mine, boring in, 542
""
experiments on ventilation,
615
Carne, Joseph, on the age of lodes, 295
""
""
39
on the current of the Deluge
(note), 62
on gossans containing tin, 493
on heaves of lodes, 671
on Relistian mine, 421
""
""
""
""
""
""
""
""
""
on the first steam engines in
Cornwall, 87
""
""
""
""
""
""
""
""
""
""
on a Roman camp, 23
on the relative ages of veins in
Cornwall, 284
on Granite rocks, 195
on red beds in Gwennap, 852
on productive lodes, 425
supposes Elvans to be true veins,
210
follows Werner, 338
on the width and breadth of
lodes, 309
Carnlough iron ores, 809
Carn Marth comby lode, 478
""
""
Granite, 202
Slate rock around, 202
Carnon Stream, section of, 75
Carnon Stream, tin deposits in, 352
""
Valley, stream works, 355
INDEX.
Carnsew, William, had seen John's charter,
""
50
extract from letter, 89
Carradon Hill Granite, 201
Carrock Mountain, copper vein, 121
Carr's pulveriser, 742
"Cassiterides, The," by Dr. George Smith,
2, 816
Castell Carn Dockan Company's gold, 265
Caverns in open cast, Parys mine, 446
Cave dwellings of the ancient Cornish, 24
Cawk, sulphate of barytes, 236, 238
Cazin, J. M., on mechanical ore concentra-
tion, 692
Cæsar's, Julius, error as to the locality pro-
""
""
""
""
""
ducing tin, 22
on the production of tin, 21
on the importation of copper
into Britain, 17
on the trade of Britain, 817
Cefnogo, old mines of, 39
Celestine found at Haddington, 186
Celts occur in many parts of England, 41
Celts, rings, &c., in bronze, found in Corn-
wall, 15
Cementing, in Kind-Chaudron system, 587
Cenis Tunnel, Mont, boring of, 539, 540
Central heat, hypotheses of, 384
Central Wales mineral district, 253
Chacewater Company, 112
Champernowne, Mr., on Roman works near
Totness, 44
Champion's, of Bristol, patent for smelting
839
""
"black jack," 133
patents the making of zinc,
Chance toadstone defined, 241
Charging and blasting bore-holes, 548
Charpentier, Von, "Mineralogical Geography
of Saxony," 330
Charterhouse lead mines, fossils in, 423
""
Mendips, sheet lead found, 35
mines on the Mendip Hills, 31
Chaudron's system of tubbing, 588
Cheadle copper works, 118
Cheddar, caverns in, 137
""
Cliffs, 230
Cheesewring Granite, 197, 201
Chert beds in Yorkshire, 246
varieties in Flintshire, 323
in Derbyshire, 233
Cheshire mines, 161
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دو
Roman lead found, 27
rocks of, 257
|
China clay, 195
""
districts, tin in, 358
Chiverton mines, Perranzabuloe, 131
Chlorite in lodes, 290
919
Christie, M., electrical-experiments, 394
Chronological tables of boring machinery,
&c., 561
Chrysoister Hut described, 24
Church, J. A., Dr., on the heat of Comstock
lode, 374
Cicero, his epistle to Atticus on Britain, 21
Cimboline coined gold in Essex, 167
""
coins money instead of rings, 126
Cinder Hill in Forest of Dean, 44
Cinders, Roman, in Forest of Dean, 43
Cinder Point on the Severn, 174
Circular movements of faults, 676
Circulating pump, 712
Circumferentor, its use, 659
Classification of ores, 705
Classifiers, vertical and horizontal, 708
Classifying apparatus, 746
""
launder, 754
minerals, 708
Claudet's silver process, 776
Clay, consolidation of, 219
""
laminated by electricity, 223
pits of St. Agnes, 204
shaft lode, Mona mine, 452
Slate, 195
""
""
""
""
""
""
""
""
analyses of, 226
or Killas, 214
structure of, altered, 385
veins in Scotland described by Williams,
274
Clayton copper mine, 118
Cleveland, Duke of, his lead mines, 461
iron ore deposit, 806, 809
""
Clifford Amalgamated mines, hot water, 375
""
""
" 424
""
produce, 430
,, temperature of, 377
""
""
""
Cligger-Head Granite, 347
Clogau St. David's gold mine, 264
Coal burnt in Cornish steam engines, 644
"
""
sill, upper, 247
used as a protective agent in tombs, 37
Coates Wheal Granite, 220
Cobalt found on Alderley Edge, 162, 250
obtained in Cornwall, Alderley Edge,
&c., 185
""
Cock Wheal, under the sea, 80, 402
"Coffens" defined, 397
Coffin, a fosse or open work, 84
Cohesion of particles, 218
Coinage towns established, 50, 51
Chevreul, M., action of sea-water on silver Cold-harbour Moor, 348
(note), 364
Chilian mill, 41
Colenso, Mr., section of tin stream, 357
Colladon compressor, 511
920
INDEX.
Collim's jigger, 760
Colours of Killas, 215
Combe Martin silver lead mines, 128
Comby lodes, 476
Commercial notes, 678
Commons, House of, committee on copper
trade, 106
Clear, St., Greenstone, 214
""
Clay-slate, 215
Compressed air used in boring, 506
Compressors, various, 509
Compressor, three-cylinder, 512
""
Darlington's, 509
Compass needle, 658
variation of, 301
Comstock lode, Great, 374
Comyn, John, Earl of Buchan, licensed to
dig for lead in California, 162
Condurrow, South, flat lode in, 409
Concentrators, 771
Cone separator, 756
Coniston mine, Lancashire, 161
Connoree mine, 471
""
copper ore and pyrites, 276
Consolidated mines account, 430
""
""
""
""
""
""
Gwennap, 425, 428
produce · for
Copper mines at work in 1777, 112
""
""
""
""
""
""
""
""
""
""
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39
duration of, 830
worked by the Romans, 37
in Wicklow, 276
Miners, Governor and Company of,
106
native in Greenstone, 222
not an article of trade with Britain, 19
no old works in Cornwall, 42
ore, annual sales in Cornwall, at
ticketings (Appendix), 892
annual sales at Swansea (Appen-
dix), 893
""
""
""
and copper from British mines,
830
"hurtful humours,” 92
occurs at certain depth, 503
,, price of (Appendix), 895
""
""
""
""
""
""
39
""
""
""
""
""
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وو
produce of for sixty years, 820
produced in Cornwall from 1726
to 1775 (Appendix), 891
produced in 1777, 112
standard, 680
sold by private contract (Appen-
dix), 895
ticketings, 679
total production of, 830
produced in Cronebane mine, 471
eighteen
""
years (Appendix), 894
temperature in, 376
""
""
formation of lodes, 346
""
Contemporaneous Granite veins, 198
""
Conybeare, the Rev. J. G., on metal-bearing
""
rocks, 852
""
213
on Devon and Cornwall rocks,
Cook's Kitchen, cross section of mine, 382
temperature of, 381
Cookworthy, Dr. William, discoverer of
""
""
""
""
دو
""
""
china clay, 95
describes divining
""
rod, 95
Cooley, W. D., maritime and inland disco-
very, 2
Coote, Sir Charles, survey of Armagh, 281
Copper, and lead veins at Alderley Edge, 261
""
cake, Roman, preserved at Mostyn
Hall, 41
early metallurgy of, 825
money value and standard,
892
pyrites worked near Llanberis, 121
in Granite, 359
found in Scotland, 274
smelted at Dolcoath mine, by Raspe,
103
ticketings, system of, 679
trade, general state of, 829
veins in Greenstone, 221
wire and spoon found on Alston
Moor, 150
Cork, county, mineral veins of, 475
Corker, Robert, a copper smelter, 103
Cornish Copper Company work copper
mines, 817
crusher, 718
crushing-mill, 723
double-beat valve, 629
""
""
""
""
fine, produced from Mona and Parys
mines, 897
""
engine, modus operandi of, 638
gravitation stamps, 729
""
""
Foreign and Colonial, 833
""
tin factors, influence on tin trade, 29
found, 38
""
imported by the Britons, 17
""
imports, 833
""
lodes and Elvan courses, 207
""
mining, 88
""
mines of Arabia, 3
39
""
hill, Cwm-ystwyth, old mining tools Cornwall, character of the county of, 399
Earldom, in 1140 and 1170, 47
iron ores of, 808
lead mines of, since 1845 (Ap-
pendix), 898
small quantity of copper obtained
in 1584, 827
of Cornwall, for seven years, Corporation of Mines Royal, 127
""
from 1792, 116
""
of Mineral and Battery works, 126
Cost-book, Dolcoath, extract from, 109
Costeaning, Borlase on, 499
INDEX.
Coster, F., Mr., bought Cornish copper ore,
828
Cylinders, separating, 748
Cyprus, Phoenicians established there, 3
ALKEY lead mine, Ireland, 468
Cotta, C. Bernhard, on mineral deposits, DAL
334
Cotton powder, 527
Country surface, conditions of and mining,398
the term applied to rocks, 285
Craddock Moor Granite, 201
Cradle drill, single acting, 524
Crank stamps, 729
Crawford Moor, gold on, 170
""
""
and silver, 163
mines, worked lead, copper,
Crazing mill, Carew describes, 65
Crockern Tor, Parliament on, 51
Croghan Kinshela, Wicklow, gold found, 172
gold of, 276, 468
""
Croker, Crofton, on gold plates found in Ire-
land, 471
Cromwell, Oliver, an ironmaster, 175
Cromwell's army, miners drafted into, 91
Cronebane mines, 471
99
copper ore and pyrites, 276
Cross-course, Great, the, in United mines,
Gwennap, 425
Cross veins in Alston Moor, 316
Cross veins, Sopwith on, 244, Henwood on, 670
Crosthwaite on the plumbago mine, 181
Crow Chert in Yorkshire, 246
Crow coal, 247
Croyl-stone, a name given to barytes, 481
Crushing and grinding mills, 721
Crushing rolls, table of result, 723
Crystallisation in Slates, 220
of quartz, 220
Crystalline forces, 301
Crystals, Westgarth Forster on, 486
Cubic feet in ton of ore, 710
Cumberland, 246
ancient mining in, 26
copper mines, 90
early history of mining in, 148
619
921
Dalton, Dr., on rainfall in Manchester,
Dana gives examples of paramorphism, 493
Danes' cinders found, 175
Danyell, Mr., a copper smelter, 93
Darby, Abraham, on iron, 175
Darcet, M., substitutes silver for steel, 495
Darlington, John, counterbalancing-rods, 635
hydraulic machinery, 637
""
""
""
""
371
on iron for boilers, 646
rock-borer, work done by, 553
single-acting drill, 525
stand for driving mine headings,
519
on mineral veins at Pontgibaud,
Dartmoor copper mines, 239
Granite, 239
"9
""
zone of mineral Granite, 199
Daubrée, M. A., on arsenical iron in coal, 364
D'Aubuisson on the structure of veins, 371
Davey's tables for copper ores, for the
standard, 680
Davey, Henry, on mechanical ventilation, 611
Davies, D. C., on cupreous shale, 360
Dead lode, 289
Dean, Mr. A., draws attention to the gold
in North Wales, 264
Dean Forest iron ores, 807
Debancke, William, signs the Derbyshire
laws, 139
Declination of the needle, 650
De Dunstanville's, Lord, notes on Carew, 73
Demetrius, a German, established brass work
in Surrey, 134
De la Beche commences the Geological Sur-
vey, establishes Museum of
Practical Geology and Mining
Record Office, 224
on Elvans, 207
on cleavage of Granite, 224
""
""
""
iron ores of, 796
""
lead mines, how worked, 310
""
""
and Westmoreland, 119
>>
on comby lodes, 476
Cumming, Joseph George, the Rev., "The
on divisional planes, 301
""
Isle of Man," 162
""
on enlargement of fissures, 303
259
Cunnack's pulveriser, 739
Cupiferous sandstone at Grinshill, Shropshire,
Cupola for lead smelting, 145
on fissure under the sea, 384
""
on gossan, 489
on heat in fissures, 382
""
on heaves, 295
""
""
reverberating furnace, 157
on the occasion of faults, 677
Cupolas, a list of, in Derbyshire, 147
on metalliferous rock, 853
""
Curtis, Thomas, works the Wherry mine, 78
""
on mining records, 815
Curwen of Workington purchased ground for
copper works, 90
on working lodes, 605
""
on North Devon Dykes, 209
Cyclopean work, near St. Ives, 14
""
on working Pool mine, 562
922
INDEX.
Delabole slate quarries, 216
Delius on rocks and veins, 330
Denbigh, records of, and its lordship, 39
Denbighshire, geology of, 262
22
mines, produce of, 443
Deny's, Sir George, report on explosives, 617
Depressions on the surface often indicate
lodes, 503
Depth of mines, 310
""
""
to which minerals may be found, 398
to which our knowledge extends, 194
Derby, Earl of, worked mines in Isle of Man,
162
Derbyshire, ancient mining in, 26
""
""
""
""
""
character of mines, 399
geology of, 232
laws of the lead mines, 138
lead ores, 144
old method of working mines, 140
picturesque vales of, 399
Romans worked lead mines, 232
Derwent Hills, veins of copper, 119
mines, produce of, 466
""
Derwentwater, Earl of, confiscation of Alston
estates, 150
Detonation, detonators, 530
Detrital tin of Trevaunance, 204
""
""
in Restronguet Creek, 352
Devon, North, Granitic rock, 209
Devonian formation, iron ore on, 795
>>
rocks, 215
Direct-acting stamps, 729
Direction and dip of lodes, 307, 308
Discovery of mineral lodes, 499
Dish, the dues paid to the lord, 83
of ore, or measure, defined, 140
Dislocations, horizontal, 677
vertical, 677
""
""
Displacements, or heaves, 669
Districts, new, for mining, 859
Divining-rod, introduction of, 94
use of, 95
Divisional planes, 301
22
""
in Serpentine, 225
Doddington, copper found there, 231
Dolcoath, copper ores sampled, 109
mine, temperature of, 607
mine, 850
""
""
Dolerites, 250
Doles, Carew explains, 65
or piles, or shares, 107
Dolgelly, copper found in neighbourhood,
263
Dolomitic Limestone, Sir C. Lyell on, 231
Dolomites contain zinc, 363
Domesday Book has no mention of mines,
45
Dooneen mine, Berehaven, 279
Double-beat valve, 629
Douran Hill, stream tin discovered at, 72
Dovaston, J. T. M., explores Roman mines.
at Llanymynech, 27
Devonshire, character of mining district of, 399 Downcast strata, 244
copper mines, 826
""
""
De la Beche on, 229
Diagram showing decrease of temperature.
on expansion of air, 508
Diallage rock, 217
Dialling with the magnetic needle, 666
""
without the needle, 667
Dia-magnetism, 438
Diamond drills for boring machine, 562
Dickenson, Thomas, Moormaster of Alston,
""
Moor, 485
150
on production of differ-
ent beds in Alston
Dieulafait, M., on Dolomite, 363
Dilated vein, 288
Dilluer, use of, 71
Dillueing sieve, 757
Dingey's pulveriser, 737
Ding-Dong mine in Gulval, 351
rounded pebbles in, 205
Diodorus the Sicilian on the Phoenicians, 4
on tin produced in Britain, 4
Diorites, 250
Dioscorides on Luna philosophica Pom-
pholyx, 132
Dipper wheel, 712
Dowsing-rod described, 94, 95
Drake's Island, or St. Nicholas's, Plymouth
Sound, 12
Drawing stuff, 588
Dressing arrangements at Dolcoath, 436
machinery, 710
manner of, described by Carew, 65
ore, axioms of, 709
""
""
""
""
ores, division of, 709
""
ore floors, 78
""
of mineral ores, 687
Drill, double-acting, 526
Drills for boring machines, 519
Drinker, Mr., on tunnelling, 542
Drivages, cross cuts, 605
Driving levels and sinking shafts, 538
Drws-y-Coed copper mine, 262, 360
Drybrook mines, Cinderford, boring in, 547
Dry compressor, 513
Dubois and Francois' boring machine, 544
stand for drills, 519
Duckenfield, Mr. Hopkins's temperature at,
""
379
Duclos, separating copper from the ores, 774
Dudley, Lord, on smelting iron with charcoal,
173
Dues, lords', 83
INDEX.
Dufresnoy on Magnesian conglomerate, 363
Dufton lead mine, 462
Dunstanville, Reginald de, made Earl of
Cornwall, 47
""
De, Lord, on the term bal, 84
Dunstone of Derbyshire, 210
""
""
Hopkins on, 243
not identical with toadstone, 243
Durham Downs, Bristol, lead and calamine
mined, 131
lease granted, 132
geological strata of, 250
| Elevatory forces, Hopkinson, 228
Elf Hills quarry, 252
923
Elizabeth introduces German miners, 83, 817
grants letters patent to German
""
miners, 93
Elvan courses and copper lodes, 207
""
""
2II
worked for metallic minerals,
analysis of, 227
course at Poldory mine, 377
courses or dykes, 283
""
""
""
""
direction of, 210
""
""
99
and Northumberland lead mines,
""
""
""
""
dislocatory lodes, 296
since 1845 (Appendix), 899
Durocher, on the presence of silver in sea-
water, 361
Duty of Cornish pumping engines, 625
""
""
engines, 639
Dykes, North Devon, 209
Dynamite, approximate weight used, 552
""
529
report on, 612
Pryce describes, 206
Elvans, 206
""
influence on mineral veins, 206
Endellion, antimony obtained from, 184
Endosmose and exosmose, 341
Enginemen, their management, 643
"Engine Reporter" commenced by Joel
Lean, 622
Engines and air compressors, 509
English Copper Company, 106
pale of Ireland, 123
""
ARTH'S crust, the mineralogical con- Ennerdale Granite, 250
EA
ditions of, 190
Earth, mean density of, 384
Ebenezer, Erasmus, separates zinc from
calamine, 5
Ecclesiastical Commissioners' lead mine, 463
Economy increased in working mines, 861
Ecton Hill copper mine, 117
""
""
"
lead ore at, 160
mine, section of, 117
Eddy, Captain, report on explosions, 616
Edmonds, Mr. Richard, discovery of a bronze
vessel, 16
Edward the Black Prince, Stannaries granted
to him, 51
Edward I. improves John's charter, 817
"
,, grants a charter to the miners,
48
robbing the Jews, 48
II. grants Stannaries to Gaveston, 51
III., charter roll of, 49
""
""
""
""
""
""
";
""
""
""
Entral Hill, Granite of, 201
Enys's "Bounds' Book," copy from, 55
Enys, John S., on Cornish engines, 638
of Enys, on divisional planes,
99
301
""
Epipolism, surface action, 347
Epsly, Thomas, first taught "shooting of
rocks," 67
Erchers, Lazarus, Assay Master of Germany,
chemistry of veins, 125
Erythra, the Sea of, 4
Espir's explosive powder, 616
Essay hatch of old miners, 562
Evans, Thomas F., on copper cakes found
in Anglesea, 38
Everett, Professor, on temperature, 609
Exhaustion of our metalliferous ores, 813
Experiments of metallic precipitation, 370
plan of, in mines, 392
Exploration of mines, 563
""
granted liberties in Cumberland, | Explosives Committee report, 615
148
copper mines at Skildane, 91
creates the Duke of Cornwall,
817
IV., charter of, "Myne-deeps," 134
» survey of Cornwall, 15
Egremont iron mine, 803, 805
Eisen-hath, iron hat, gossan, 489
Electrical experiment on clay, 386
change in copper ore, 494
""
Electric firing, its economy, 537
Electricity of veins should be investigated,
867
""
various, 529
Exports and imports of tin, 819
Eyes of the mine, picking out, 606
"FAIR
AIR ground,” miners' term, 215
Fallowfield, strata at, 250
Faraday on magnetism, 437
on electricity, 99
99
Farnham and Knaresborough, copper found
at, 161
Famp, decomposed Limestone, 247
924
INDEX.
""
miners' claim to cut wood, 146
""
on Derbyshire lead ores, 144
""
on loughs or levels, 142
""
on mine timbering in Derbyshire, 577
on the sales of lead ore, 144
Farey, John, on the copper mines of Derby- | Forster, Westgarth, on discovery of mines,
shire, 116
""
502
on the throw of veins, 297
on fissure veins in Cum-
berland, 311
on dressing ores, 670
""
""
""
""
""
on the gravels of Derbyshire, 233
on rake veins, 286
""
""
on keeping mine plans, 579
on Teesdale lead mines,
""
466
on the geology of Derbyshire, 232
on the toadstones, 237
report on Borrowdale mine, 182
Fault, Great Derbyshire, 233
Faults, movements producing them, 675
on Snowdon described, 263
their influence, 668
""
""
Fayes mine, Combe Martin, 129
Feachsen, Modestin, on assaying, 330
"Feasible ground," miner's term, 215
Fell-top Limestone, 247
Felspar, porphyry, or Elvans, 206
""
specific gravity of, 69
Ferguson, Henry J., on dressing ores, 692
Field, Frederick, on silver in sea-water, 364
Finland producing tin, 7
Fire-damp in the Van mine, 488
Fire-engine, steam pumping engine, 87
Fire-stones of Derbyshire, 234
Firing machines, by electricity, 533
""
operations by electricity, 537
Fish-hooks, made by the Cornish of tin, 14
Fitz-Simmons on the mines at Brada, 162
"Flats" and " pipes" in Minera mines, 441
stanniferous, or "carbonas," 405
Flat lode on Carn Brea Hill, 407, 408
""
""
sections of, 408
Fleitmann on rapid formation of mineral
veins, 369
Flintshire veins, 322
وو
";
Foster, Dr. Clement le Neve, on Wheal Lovell
""
""
""
""
""
""
""
""
488
lodes, 410
on Balleswidden,
349
on the flat lode,
408
on Wheal Mary
Ann, 434
on Prosper and
Michell, 420
on the Van lode,
Fos-y-Bleiddiaid, a Roman fosse, 32
Foulis, Thomas, has "a tack" of all mines in
Lanark, 163
Foulkes, J., dials the Borrowdale mines, 182
Fournet, M., on regular formation in veins,
""
371
Etudes sur les Dépôts Métallifère,
336
on Winzel lode, 479
""
""
on copper-bearing slates, 853
Fowey Consols, expense of working, &c.
(Appendix), 896
Fox, Charles, mining memoranda, 863
""
Joshua, experiment in Pennance mine,
393
Fox, Robert Were, electricity of mineral veins,
electrical currents in veins,
experiment in Pennance
mine, 393
99
""
""
geological section of, 261
388
""
Flow Edge mines, 457
mines, electricity detected in, 390
lead lodes in, 399
""
""
Flucans, 670
Flucan vein, 290
""
vein in Polgooth mine, 210
Fluor spar in Allendale and Weardale, 480
""
in Derbyshire, 479
""
lode, 480
Flying veins, 289
"Fodinæ Regales," by Sir John Pettus, 125
Forbes, Dr., on the Land's End district, 221
Forces, uplifting, causes of, 220
Foreign tin, prices per cwt., 819
Forge, the, at Bodfary, worked by the
Mathews's, 40
Forster, Westgarth, on Alston iron mines, 459
""
"
on Alston mine, 316
on cauk spar, 482
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""
""
""
""
""
""
33
وو
""
""
""
""
""
""
laminates clay by electri-
city, 388
on heat in fissures, 382
on mineral changes, 495
on mineral veins, 338
on rock temperature, 383
on temperature of mines,
608
producing mineral veins,
395
temperature in Levant
mine, 383
temperature of deep mines,
379
wedge for blasting, 653
Foxdall, Isle of Man, 324
Frame, dead, 769
INDEX.
925
France, North-western, producing tin, 7
Gingins of shafts in Derbyshire, 581
Francis, Colonel Grant, on the smelting of Girdle or Till bed in Cumberland, 248
""
copper, 89, 826
South Wheal, flat lode in, 409
Frazier, Alexander, works Parys mine, 444
Freestone, a name given to Greenstone, 212
French stands, for carrying boring machines,
521
Frosse, Ulrick, works copper mines, and
melting master, 89
Fulminate, 531
Furness district, iron ores of, 796
Fuses, electric, 536
Fuse, low tension, devised by the author, 533
ADS and wedges, 656
GADS
Gadez (Cadiz), a Phoenician port, 4
Gaetzschmann, Bergrath, on ore dressing,
690
Galena in coal measures at Whaley, 259
""
270
of Lead Hills and Wanlock Head,
Galleries driven in soft ground, 579
""
timbered, 581
Garras mine, near Truro, 130
Gas found in metal mines, 489
Gash veins, 289
Gaunse, Joachim, German miner, 92
""
and Needham, on copper mines in
Cumberland, 92
Gaveston, Stannaries granted to him, 51
Geikie, Prof. Archibald, on temperature, 607
geological structure
""
وو
of Lead Hills, 268
Gelatine, blasting, report on, 616
""
nitrated, 529
Gellert on chemistry of minerals, 330
General remarks and conclusion, 879
Genoa received tin from Cornwall, 46
Geological position of metalliferous rocks,
""
193
Survey map, 190
Gerhard, C. A., essay on veins, 331
German miners improved ore dressing, 688
inhabit an island in Derwent-
water, 158
""
""
Glandore mineral channel, 475
Glenarm iron ores, 809
Glendalough mine, Wicklow, 275
veins, 469
""
Glenmalure mines, 281
Glossary of terms, 907
Gloucestershire geology, metalliferous dis-
tricts, 232
Gob stowing, 582
Godolphin Hill Granite, 201
"God's Blessing," name given to the mine at
Hilderston, 164
God's gift mine, one of the Caldbeck mines,
93
Gogofau gold mine, 168
Gold and galena, rate of fall of grains of,
707
""
وو
""
""
""
""
""
collected by the Britons, 201
collected from the tin streams in Corn-
wall, 167
found in various tin streams, 352
quantity found in the United Kingdom,
173
found in Wicklow, 172, 468
in Scotland, 275
mine at Gogofau, Roman, 43
mines, royal grants, leases for working,
126
of Dolgelly district, 264
,, separated from pyrites, 849
""
""
sought by the Roman invaders, 42
spheres of fall of, in water, 707
Golden venture, Parys mine, 444
Goldscope mine, copper, 90
Gonell, Joachim, gift of a copper mine near
the Water of Leith, 122
Gossan copper ore in Gwennap mines, 425
its occurrence, 489
""
Governor and Company of Lead miners,
""
in England, 157
""
463
mine adventures
Gralliot, M., table on boring results, 507
Granite, analysis of, 227
194
alteration of in Tresavean, 379
""
""
""
""
introduced, 83
beds of Derbyshire, 233
""
""
introduce the divining-rod,
""
mines in, 201
94
""
primitive, 200
introduce the term Killas,
""
""
""
specific gravity of, 69
و,
""
215
names of, 92
وو
33
Gilbert, Adrian, discovers a new silver mine,
""
""
129
Mr. Davies, on rainfall, 619
on stanniferous
phyry, 79
وو
stannified, burnt for tin, 79
veins in Slate, 283
veins in Granite, 289
""
veins, St. Michael's Mount, Trewavas
Cliff, 206
por-
""
water pumped from, 621
Granites of Playfair (Sienites), 234
926
INDEX.
Granites of Leicestershire, 234
Granitic formation, diagram of, 197
Grant of tin bounds to Schutz, 54
Grauwacke veins, Conybeare on, 213
""
in Devonshire, 239
""
""
a Saxon miner's term, 216, 217
""
of Isle of Man, 266
Gravell Hill iron mine, 800
Gravitation stamps, 729
Great and Scar Limestone, section of, 460
Great Bavington, whin sill at, 252
Greathead, Rev. Samuel, quoted, 6
Great Hucklow, section of lode at, 242
limestone in Derbyshire, 241
""
whin sill, occurrence of, 249
Greeks knew that tin came from Spain, 5
Green, Foster, and Dakyns on the toad-
stone, 240
Greenside mine, Penrith, silver lead produced,
836
Greenstone rocks in the Earth, 212
""
""
water pumped from, 623
analysis of, 227
212
Greenwich Hospital, becomes proprietors of
""
""
""
ore, 458
""
""
Alston Moor, 150
duty lead ore from 1768
to 1881 (Appendix), 899
lead mines, 458
purchases Alston Moor
Gregory on pressure engines, 627
Greisen, described by Dr. Foster, 420
Grenelle, artesian well of, 379
Grenville Wheal, flat lode in, 409
Gribble, James, engines for Dolcoath, 632
Griffith, Mr., describes Glenmalure, 281
Griffiths, Sir Richard, on Irish mines,
326
Grindstone sill, 247
Grit or plate in Yorkshire, 246
|
Gwennap district, 209
""
""
""
""
length of lodes in, 304
lodes on, 428
""
mines, description of, 426
Gypsum in Derbyshire, 233
HADE and throw" of veins, 244
Hade of veins, 286
Hæmatite, brown, on Brendon Hills, 231
at Winford, 232
""
""
""
""
""
iron ores, derivation of, 805
red, of Whitehaven, 802
,, Furness, 802
99
the densest body known, 384
Haidinger on parasitic change, 492
Halfpence and farthings, coined 1694, 106
Halse quoted by Jenkins on St. Mighele's
Mount, 13
Hals's "History of Cornwall," discovery of
coins, 23
Hammers and sledges, 452
Hanbury, Major John, first made tin plates
at Pontypool, 60
Hand and machine boring, relative cost of,
556
Handbarrows, 712
Hand-boring described, 304
Hanging side of a vein, 286
Hanno, Periplus of, quoted by Lewis, 11
Happy Union tin stream, section of, 357
Hauling underground, 549
Hausmann, Professor, on change produced
by heat, 220
Hawkins, Sir Christopher, notices gold in
Ladock, 168
""
Mr., on contemporaneous veins,
419
Hawkins, Mr. John, on Cornish rocks, 209
on geological changes in
Cornwall, 14
""
""
""
on the sale of tin, 45
on the Wherry mine, 79
Hayle, copper veins found at, 23
Hazel rock, so called in Cumberland, 247,
Grizzley or slide, 716
Groove-fellows defined, 141
Grote on the Phoenician traders, 20
Grouan or Growan, soft Granite, 86
Gruffs or mines on the Mendip
Hills,
36
Guide," local name in St. Just for
cross-
courses, 205, 401
Healey Field lead mine, 405
Heat of compressed air, 509
Guides for skips in mines, 599
""
Gulf Rock, or Wolf Rock, 9, 13
of water in Wheal Clifford, cause of,
431
Guncotton, report on, 616
249
Gundry, John, re-opens Wheal Vor, 414
Gunpowder first used for blasting rocks, 1689,
""
67
report on, 616
Gurnard's head, Greenstone of, 212
Gurney, Sir Goldsworthy, steam jet, 615
Gunter's chain for surveying, 659
Heath, on ancient and present state of the
Scilly Islands, 9
Heaves in St. Just, 401
""
of lodes, 293, 295
""
or displacements, 669
Helvellyn lead lodes, 319
Hemp and wire ropes compared, 594
Henckel on zinc, 133
INDEX.
Henderson, James, on dressing tin and copper
ores, 689
Henry, Bishop of Winchester, had a grant of
gold and silver mines, 130
Henry III., ironwork for his tomb, 177
Henry VII. declares all the charters void,
51
encourages the tin trade, 817
Henry VIII., Act respecting tin wares,
5I
Henwood, W. J., definition of Elvan, 208
direction of joints, 299,
454
""
""
""
""
""
19
300
on Anglesea, 324
on Carnon stream, 75, 352
on the colour of rocks,
202
on heaves, 669, 670
on intersections, 669
on "Jews' house" tin, 358
observations on electricity,
393
on pumping water, 622
on Relistian Slate, 421
on subterranean tempera-
ture, 376
on temperature of rocks,
609
on temperature of Poldory,
377
on tin and copper mines,
Herland mine, Granite in the lode, 422
Herodotus quoted on tin, 2
Herodsfoot mine, 432
927
Holes bored for Darlington's machine, 554
Holland, Mr., on Alderley Edge, 259
""
""
Henry, "General view of the Agri-
culture of Cheshire," 257
sales of tin in, 821
Holy Well gives name to the town, 262
Holywell, group of veins, 322
mineral district of, 262
""
Homer mentions tin, 5
Hooks, safety for skips, 600
Hoosac Tunnel, square cut system of boring,
543
Hopkins on dunstone, 243
وو
""
وو
on faults, 298
researches on physical geography,
228
on the Toadstone, 238
Hornblende Greenstone, 214
وو
Hornblower's
""
""
Slate of the Lizard, 217
combined cylinder engine,
627
erecting engines in Stafford-
shire, 112
valve, 629
Horner, Mr., found green carbonate of copper
on Mendips, 231
Horses in the lode, 604
Horse whims, 590
Hot lode in Clifford Amalgamated, 377
Houghsetter, Daniel, a German miner, 93
works mines in Cardiganshire,
""
152
Hubert, Archbishop of Canterbury, admin-
istered affairs for Richard Cœur de Lion,
48
Herring, H., obtained copper ores, 1584, Hucklow, lode at, 242
89
Hexham, zinc works at, 133
Higgs, Samuel, finds chalk flint in Balleswid-
den mine, 422
High-pressure engine, Trevithick's, 628
Hilderston, in Linlithgowshire, silver mine,
163
Hilton, Henry, lease from, for a thousand
years, 149
Himilco, discoveries of, II
Hingston Hill, Callington, meeting of tinners
on, 49
Hocking, John, on stamping-engine, 730
Hocking's calciner, 771
Hockstetter, David, a German miner, 91
Hodbarrow iron mines, 801
Hodge's classifier, 755
Hoefer, Hans, on faults in veins, 669
Hoefer's revolution of faults, 672
Hoffmann, J. George, Assessor to the Coun-
cil of Mines, 327
Hofmann, A. W., on filtering the water of the
Thames, 219
Hudghill Barn mines, 457
Hughes, Mr., smelts Anglesea lead, 445
Hull, Edward, on Alderley Edge, 260
Human skulls found in Pentuan stream,
357
Hummocks of mineral Limestone and Toad-
stone, 240
Humphrey, William, grant of Queen Eliza-
beth to, 126
and Shutz have a patent of all
the calamine, 133
Hundt, Bergmeister, on dressing ores, 696
Hunt, John, leases Wheal Rose mine, Hel-
ston, 270
continuous jigger, 695
Husband's four-beat valve, 631
safety governor, 664
">
""
testing of stamping-engine by,
726
"Hushing" described, 503
Hutchinson on the Borrowdale works,
180
Hutton on formation of veins, 483
928
INDEX.
Huxham, Hort, Mr., report on explosives, | Iron, to correct needle if surveying in its
615
Hydraulic machinery at Alport mine, 637
Hydrostatic balance, 699
Hydrothermal action forming mineral de-
posits, 373
Hydrous agency, William Wallace on, 459
Hyltons, of Hylton Castle, proprietors of
Alston Moor, 148
Hypothesis on lodes not satisfactory, 346
GNEOUS centre, 398
IGNE
Iktis, the, of Diodorus, 4
Illogan district, length of lodes, 305
Imports and exports of tin, 819
into Arabia, &c., 2
Inclination of needle, 301
""
or dip of the needle, 658
India, tin obtained from, 2, 5
Increase of temperature on compression of
air, 508
Infiltration, lateral, influence of, 347
Injection during igneous fusion, 348
Intensity, magnetic, 658
Ireland, gold ornaments found in, 172
""
28
vicinity, 663
works of the Romans in Dean Forest,
Island, the, St. Ives, 12
Islay, Isle of, veins or strings in, 271
"
""
how ore was procured, 272
Isle of Man, depth of mines, 310
""
""
""
""
""
""
""
principal mines, 324
primitive rocks of, 266
lead ore since 1845 (Appendix),
901
mining operations in, 162
Isles of Cassiterides, Strabo's description, 9
JAMES, Captain Abraham, Report on
""
Sir Henry, on a block of tin
found in Falmouth Harbour, 19
James I. opens the New River at Islington,
152
Jars, M., on Carclaze mine, 417
""
on mechanical ventilation, 612
Jews' houses, Pryce on, 17
exile of, 49
leavings, I
""
""
""
lead ore produce since 1845 (Ap-
pendix), 903
""
""
""
tin, 18
manganese produced in, 184
Milltown lead mine, 166
""
""
""
mines in, 468
""
Wicklow, geology of, 275
Irestone, name of Greenstone in Cornwall,
212
Irish Hill iron ores, 809
99
Iron, 173
severely oppressed by King John, 48
tin raised in the time of John, 47
Jeffery, Richard, engineer at Dolcoath, 632
Jigger, continuous plunger of, German inven-
tion, 696
Jigging machinery, history of, 694
machines, 757
Joel, the prophet, on the children of Judah
as slaves, 18
John, King, expels the Jews, 817'
mines, 123
""
and manganese disseminated in rocks,
361
""
""
""
""
""
and steel wire ropes, 594
gives the tinners a charter, 817
grants a charter to tinners, 48
tin mining in his reign, 47
""
""
""
found and melted in Britain by the Johnes, Mr., proprietor of Ogofau mine,
Romans, 20
malleable, prices of, 176
ores, brown and cretaceous, 798
وو
""
""
""
""
""
""
""
""
""
""
""
""
""
33
""
""
""
character of various, 807
geological condition of, 792
obtained in 1881, 844
of the coal measures, 808
of United Kingdom, 793
on the Mendips, 231
production of, 1881 and 1882,
808
Romans worked, 43
168
Joints in rocks, 299
Jordan's pulverisers, 741
Jordan, Thomas, first keeper of mining re-
cords, 814
and Darlington patent a scheme for
rotating piston, 524
Julia Wheal, comby lode in, 476
KANE, SIR ROBERT, industrial re-
total production of, in 1881, 1882, KA
810
quantity smelted in 1882, 808
""
""
sources of Ireland, 124
on Irish copper ores
""
""
""
33
various characters of, 805
sold at Swansea, 277
Kane, Sir Robert, silver assays, 282
Kaclin near St. Austell, 355
Kaolinisation producing heat, 375
Keates, Mr., on the standard, 678
"Keenly gossan," a kindly gossan, 489
INDEX.
Kendal, J. D., on the Furness iron ores,
803
Kenmare Bay, copper ore in, 277
""
Mining Association, 279
and Bunter sandstones, 257
Kenrick's, John, "Phoenicia," 3
Keswick, copper smelted at, 826
""
copper works, 90
""
mines around, 399
""
silver lead mines, 318
""
smelting operations at, 119
Keuper sandstone, Hull on, 260
929
Lawson, Dr. T., on extracting zinc from cala-
99
zinc, 839
""
mine, 132
proved calamine contained
Laxey, a grauwacke slate near, 266
Isle of Man, 324
""
Layard on the Assyrian bronzes, 3
Lead and silver, 835
""
""
""
produced in United King-
dom, 1848 to 1871, 898
bearing district of Shropshire, 253
black and white, 19
Hills, described by Williams, 270
district rocks, 267
""
""
""
""
""
and Wanlock Head, map of dis-
trict, 269
mines, number of in Derbyshire, 239
of Cornwall since 1845, 898
named by Pliny, 19
ores, estimation of, 685
وو
وو
""
Kibbles, 594
""
""
""
wrought-iron, introduced by Tre-
""
vithick, 625
""
Kilbricken mines, Ireland, 282
""
Killas, analyses of, 226
""
"">
clay state, 195
""
""
colours of (Pryce), 215
""
""
""
""
""
""
six sorts (Pryce), 215
""
"
Kilns, washing, 714
""
""
defined, 214
Kinahan, G. H., section of fault, 475
Kind-Chaudon's system of shaft-sinking,
584
King, F. J., process for separating iron,
777
Kitto, Mr., on Foxdale mines, 325
Kitty Wheal lode, length of, 304
Knockmahon, &c., mines, 278
Koffens," old open workings for tin, 10
Kynance Cove, divisional planes, 225
ABYRINTH or settling pit, 749
Lackamore mines, 280
""
""
""
in Derbyshire, 144
moisture in, 710
of Ireland, all argentiferous, 282
of Derbyshire, 238
old method of getting, 144
on the Mendips, 231
"sampling of, 779
pig of, found in Hampshire, 25
pigs, Roman weights of, 35
raised by Governor and Company,
158
said to have been sent to Greece,
II
veins in Cardiganshire, peculiarities of,
321
Lean, Messrs., water pumped from Granite
وو
624
and Slate, 623
Joel, "Engine Reporter," 623
Thomas, report on Cornish engines,
Lease, length in Alston Moor, 312
Leases in 1778, 83
Lake district compared with Isle of Man, 267 Leasing a mine, 107
""
""
""
""
rocks of, 249
mines, 150
Leland quoted respecting St. Ives, 90
Ledger side of veins, 245
Lamb Bottom Cavern, on Mendip Hills, Lehmann, D. J. G., on fissures, 330
3I
Lamination, planes of, 300
""
of clay by electricity, 223
Lancashire, iron ores of, 726
Lasins, G. O. S., on mountains, 331
Latten and lead, 841
""
""
ware mentioned by Beckmann, 46
mines of, 134
Launder or classifier, 753
Laws of the Mendip mines in reign of Ed-
""
ward IV., 136
relating to mineral deposits, 327
of the lead mines of Derbyshire, 139
Lelant and St. Ives districts, 405
Leigh, Charles, "Natural History of Lan-
cashire," 161
Lemielle's ventilator, 619
Lemon, Sir Charles, Chairman of Commit-
""
""
tee on Mining Records,
814
offers to found a mining
school, 873
William, on the price of block tin
(and note), 61
Lethowsow, the channel between the Land's
End and Scilly, 13
930
INDEX.
Level, props in, 580
the Y, 669
Levels in Cumberland mines, 310
""
""
""
lining of, 580
in Gwennap, extent of, 429
Loo Island, 12
cost of driving in Alston Moor, 579
Le Verrier on mechanical ventilation, 612
Lewis's, Sir George Cornewall, "Astronomy
of the Ancients" quoted, 8
Lias, middle, iron ores of, 797
Liberties and customs of Derbyshire mines,
138
“Lid-stone ” to a vein, 237
Lord's part, one-fifteenth, 107
Lossiemouth, Williams on, 272
copper ore in breccia, 360
Lovell, East Wheal, lodes in, 410
Low, Mr., system of ventilation, 614
Lower, Mark Anthony, on Sussex iron works,
178
Luganure mine, Wicklow, 275
""
""
""
lead mine, 499
production of lead and silver, 469
produce of, 280
veins in Granite, 280
Limestone, Great, relation of the lodes, 469 Luminous appearance in veins, 500
";
iron ores in, 802
""
of Anglesea, 260
""
scar, lode in, 460
""
""
shale, 234
twelve-fathom, 245
water pumped from, 623
Limestones, carboniferous, 235
Limonite on Eisen Hill, 231
Lincolnshire iron ores, 808
Lindal Moor, iron ore deposit, 803
Lindsay, Lord, on the mines of Scotland, on
Lundy Island, eleven dykes in, 209
Lusitania producing tin, 5
Lydford law, justice of, 51
Lyell, Sir Charles, on lower Llandeilo forma-
tion, 252
Lyndesay, Mr. John, on working lead mines
at Glenesk, 165
Lyson's "Magna Britannia" quoted, 128
his contract with Hans Ziegler (note), MACHINES for dressing ores, 790
166
Lines, Austrian, 709
Lionnesse, Dr. Borlase on the, 13
Liskeard district, length of lodes, 305
""
lead mines, 432
Lithium in Granite rocks, 369
Lithofracteur, 529
Liverpool cotton-powder, report on, 612
Lizard Point, direction of rocks, 225
Llandeilo flags, Shropshire, 252
Llandudno copper mine, 456
""
soil of Roman level found, 29
Llanrwst, lead mines near, 263
Llhwyd, Mr., on the term bal, 83
"Load workes," Carew on, 63
Loam, Mr., on Cornish engines, 649
Loch-holes or bryns, 486
Lodes at Wheal Mary Ann, 435
bearing of, as shown in planes, 502
comby, 476
definition of, 283-285
""
""
""
""
""
filing of, 476
""
560
""
""
""
direction and dip, breadth, 307, 309
length of, 303-305
in Balleswidden, 350
in Ding Dong mine, 351
underlie of, 306
value of, 586
Loe Bar, separating Loe Pool from the sea,
""
413
Pool, valley of, 410
London Lead Company, 464
Longmaid's process for copper, 772
Machinery, extent of, in Clifford
Amalgamated, 431
Mackworth, Sir Humphrey, bought mines of
Edward Pryce,
155
""
""
verses on, 155
""
""
bill to prevent
his leaving Eng-
""
""
land, 158
publishes a "Vindication," 158
claims of, 159
McMurtrie, of Radstock, on the Harptree
caverns, 32
McNeille, Bedford, on tin dressing, 789
Maes-y-Safn main lode, 323
"Magna Britannia," Lyson's, quoted, 128
Magnesian Limestone, 236
""
""
Sir C. Lyell on, 231
Magnetic elements (note), 438
""
""
""
iron ore, separation of, 777
meridian, 301
north, 301
Magnetism-magnetic bodies, 437
Main chert in Yorkshire, 246
""
rods, breaking of, 646
Malaguiti, on silver in sea-water, 361, 364
Man-engine at Dolcoath mines, 436
at Minera mines, 638
history of, 648
""
""
trial of, 650
99
Manganese, ores, quantity obtained, 849
""
182
in Devonshire and Cornwall,
INDEX.
Manganese, production of since 1872 (Ap- Metamorphism, 491
""
pendix), 906
in Scotland, 275
Marbles, Derbyshire, 235
Margraf distils zinc, 837
Mark, St., stamp on tin at Venice, 47
Marlstone, iron ores of, 797
Marsden & Co.'s stone-crusher, 721
Marseilles, overland route to from Britain,
19
Mary Ann mine, Menheniot, 433
Masonry in mines, 576
Materials, &c., improvements, 862
Mathews's, of Denbigh, iron workers, 40
Maund, Sandy, discovers the mine at Hilder-
stone, 164
Mawe, John, mineralogy of Derbyshire,
118
on mines near Chorley, 161
""
""
""
on Parys Mountain, 122
Metamorphoses of rocks, 194
Meteoric phenomena, United mines, 500
Meteors seen over Swanpool, 500
Metric system, 709
931
Meyrick, Sir Samuel Rush, publishes a list of
the Cardiganshire mines,
159
""
""
""
Rush, on gold in Wales, 20
"History and Antiqui-
ties of Cardiganshire," 151
Michell and Tregoning's pulveriser, 738
Middleton, Sir Hugh, brings the New River
from Ware to Lon-
don, 152
works Cardiganshire
""
""
mines, 152
Mill Close mine, section of toadstone in, 237
horizontal, 741
Millimetre, French, 739
Max Müller, Prof., on the Jews and tin | Mills and roller, Cornish, 721
mines, 50
Meade, Richard, on iron mines, 43
Measures for black tin in Carew's time, 65
Mechanical boring, 505
""
""
character of ores, 671
force used to compress clay, 218
Mechanical ventilators, efficiencies of, 612
Memorial on the preservation of mine plans,
814
Mendip Hills, geology of, 230
""
speed of, table of result, 724
Millstones, Peak, manufactured at Belper,
234
Millstone grit of Derbyshire, 234
Milltown lead mine, 281
Mining-fields only partially explored, 866
Minera mines, financial position, 442
lode, 262
""
Union and Central Minera, 443
mines, boring in, 544
""
winding-engines, 648
Minerals, association of, 495
Mineral and battery works, 94
""
""
mines, 131
""
""
""
""
lead obtained, 36
Roman mines in, 31
""
map of, 134
""
""
Mendip Minerys," title of charter, 134
Mendips, Limestone of the, 230
""
corporation of,
126
grant of Queen
""
Elizabeth, 125, 126
classifying, 706
districts, how discovered, 497
""
""
lodes, length of, 305
laws of Derbyshire, 138
""
""
Menheniot mines, produce of, 434
Meridian, true, established by Royal Corn-
wall Polytechnic Society (note), 301
Merionethshire, gold in, 169
Metallic ores scarce in primitive Granite,
abundant in secondary
Granite, 202
""
,, in Yorkshire, obtained from
east and west lodes, 311
Metalliferous character of rocks, 193
minerals, exhaustion of, 813
ore at great depths, 859
""
""
""
""
""
deposits, phenomena of,
367
"richness" of, in rocks,
195
separated from rock, 698
Metallurgy, dynamical, 693
Metals, dissemination of, in rocks, 361
33
mines, Denbighshire, 439
produce left in Cornwall, 873
productions of the United Kingdom,
846
statistics, origin of, 815
veins in Shropshire, 252
of Lead Hills and Wanloch
Head, 269
definition of, 284
""
""
""
"
""
theories respecting, 395
""
Mine agent on mining, 865
Adventurers, Company of, 154, 156
Adventure, pamphlets published on the
(note), 158
""
""
""
""
obtained from the ores, 847
originate below, Cotta's view, 335
to find cubic feet in lode of, 686
27
definition of, 283
""
workings on the Mendips, 232
""
surveying, 655
30
932
INDEX.
Miners' Association formed, 874
objects of, 875
of Cornwall, 190
Consumption, 649
Mona mine, section of, 451
Montgomeryshire, metalliferous district, 253
Roman workings, 28
lead lodes, 320
وز
Derbyshire, their rights and laws, 139 Monthly fall of rain in Cornwall, 621
""
""
""
""
""
""
""
rocks, 859
""
dials for surveying, 659
their distinguishing character, 876
Mines, Cornish, winding-engines, 646
""
""
""
""
discovery of, 497
depth to which worked, 310
distribution of, 191
in which fossils have been found, 423,
424
""
produce of
278
33
Knockmahon,
Royal, antiquity of, 126
""
""
defined, 125
""
grant of, 127
""
""
in Cardiganshire, 150
""
""
""
""
""
Society, 94
&c.,
Monsal Dale tunnel, 234
Moore, Charles, on organic remains in lodes,
423
Moorstone, 194
More of Linley Hall discovers Roman re-
mains, 27
Morris, Lewis, "A Short History of Creuthyn,"
159
Moses mentions tin, 1, 5
Mottram, St. Andrew's, copper found at,
258
""
denuded rocks at, 260
Mountain Limestone, geology of, 234
""
""
mine (Berehaven), 279
system of Elie de Beaumont, 297
Mount's Bay, submergence of, 13
Society of, propose to farm the Mount Sorrel Granite, 234
tin, 61
working in Shropshire 1881, 256
Mining, ancient, 399
at Alderley Edge, 257
Company of Ireland, 278
"9
""
""
districts, character of, 399
districts in Yorkshire, 311
""
""
""
during the Roman occupation, 21
in Cornwall in 1671, 563
in Greenstone rocks, 214
in the eighteenth century, 45
previous to the Roman invasion, I
Record Office established, 813, 878
fac-simile of Edward IV.
charter, 134
""
""
""
""
وو
وو
""
tools, 651
""
Mucruss copper mine, 124
Mudstones of Garepool, Cairnsmore, 269
Muirhead's "Mechanical Inventions of James
Watt" quoted, 113
Mulberry mine, an open quarry, 354, 420
Mullion, direction of rock, 225
Mundicy lode, 289
Murchison, Sir Roderick, "Siluria,” quoted,
""
tem, 252
856
on Silurian sys-
Musconetcong tunnel, square-cut system of
boring, 543
Mushett, on Phoenician metallurgists, 175
Mynedries of the Forest of Mendip, 135
plans of Wheal Vor, Mynedeeps, Lawes of, 135
416
Miocene, iron ores of the, 798
Miscellaneous minerals, 845
Mitscherlich, Professor, on internal changes NANGILES mine, elvan courses, 211
in crystals, 493
Moissenet, M., Ecole des Mines, on the stand-
ard, 681
on ticketings, 816
""
""
""
""
on dressing tin ore, 816
""
261
وو
on lead mining in Flintshire,
Moisture in ores, 708
Molybdena found at Wheal Crofty and Gwen-
nap, 185
Molyneux, Mr., found copper on Cannock
Chase, 259
Mona mine, Anglesea, copper produce (Ap-
pendix), 896
""
""
""
39
great open cast, 451
produce of copper water, 451
Nantile copper mine, 360
Nantile Vale copper mines, 263
""
""
of, copper mines in, 399
Nash, Dr., history of Worcestershire, 174
Neath, in Wales, melting house, 89
Necker, Albert Louis, on metalliferous de-
posits, 336
Needham, George, a German miner, 92
Needle, variations of, 502
Nentforth level commenced, 1760, 150
Nenthead mines, 313
Newcomen, of Dartmouth, his engine at
Griff, Warwickshire, 111
New Glencrieff vein, description of, 270
Newlands, copper found at, 119, 120
rich vein of copper at, 90
Newton's combined miner's dial, 662
Newton, his engine counter, 639
Newtown, Roman workings at, 29
Nicholas's pulveriser, 749
Nicholas, St., Island, 12
Nickel, 686
Nine Maiden Downs, granite of, 201
"Nipt-up" veins, 238
Nitro-glycerine, 529
INDEX.
Nola, Bishop of, introduced a bell, 45
Nordan on Roman tin mine, 23
Northamptonshire iron ores, 806
North Down cross-course, 296
Northern counties lead mines, 456
Northumberland, ancient mining in, 26
Earl of, law-suit with Queen
""
""
""
Elizabeth, 127
cop-
Earl of, owns Keswik
per works, 91
Geological strata of, 250
Nottinghamshire, a pig of lead found, 27
OATES, Captain, on temperature of
Tresavean mine, 383
Observations of mines in 1673, 397
on systems of boring, 547
""
Ochres, Derbyshire, 235
Ocynhausen, Von, on Carclaze tin mine,
417
Ogofau gold mine in Carmarthenshire, 168
Ogo, name of old workings, 40
Ogo-Wyddyn, name of old mine, 40
"Old Borrowdale," by G. F. Crosthwaite,
181
"Old Men's Dwellings," described by Mr.
W. C. Borlase, 18
Old sea-coast, St. Agnes, 204
Oolite, iron ores of, 795
Oppel, Von, subterranean geometry, 328
"Ora Maritima," by Avienne, II
Ore dressing, high percentage of, 793
machinery, table of, 792
estimation of, in dressing, 679
""
""
""
""
""
""
found in Yorkshire Limestone, 246
hardness or brittleness, 698
sampling of, 779
,, valuing of, 685
Organic nature contains copper, 365
remains in mineral lodes, 422
Ormes Head copper formation, 456
""
Great, copper mine, 455
""
""
""
""
""
lodes in, 262
""
""
""
""
""
""
""
Roman implements
found on, 37
Romans worked copper,
90
sections, 456
Otes, John, on a cargo of copper, 90
933
Otley, Wm., on Borrowdale blacklead mine,
179
Ovoca mines, 474
"2
pyrites produced, 275
Oxfordshire iron ores, 806
Oxland's calciner, 777
""
""
Dr. R., finds cinnabar at Sulphur
Bank, California, 373
finds silver in hot springs,
""
374
process
wolfram, 774
for
separating
PACK walls, 580
Papal See and England, a convention,
1337, 47
Paramorphous crystals, 493
Paris, plaster of, laminated by electricity,
387
Park Mines, Denbighshire, 443
Parkside mines, Whitehaven, 804
Parliament assents to the creation of Duke
of Cornwall, 49
""
of tinners, 76
Parr Moor, wooden spade found in, 30
Parys Mountain mine, 122
""
""
""
""
""
""
alum, antiquity of, 444
copper produce (Appendix)
897
and Mona mines produce, 453
mine, section across strata, 447
section of workings, 448
Patterson's stamps, 736
""
""
Paul, Dr., on miners' diseases, 649
Peak, High, Derbyshire, laws and customs,
139
Peasy ore, variety of lead ore, 145
Pearsall, Thos. J., letters on Mendip charter,
135
Pegolotti, F. B., on the importation of tin in
Florence, 46
Pembroke, Earls of, governors of the Com-
pany of Mines Royal, 153
Penalva, St. Ives, Greenstone, 221
Pennant describes old mass of copper, 41
""
""
""
37
on iron ores, 43
Parys mine, 444, 445
Roman wedge found in Flintshire,
Pendarves, Sir William, copper-smelter, 103
Pennance mine, electrical experiments in,
393
Penrose mines, near Helston, 130
Penryn Granite, 197
Pentuan Valley, tin deposit, 357
Percussive rock-boring machinery, 560
Percy, Dr., on the early metallurgy of cop-
per, 825
302
934
INDEX.
Periplus of the Erythræan Sea, z
Permian formations, 240
Perran iron lode, 799
Sands mineral works, 89
Pitt, Thomas, Lord Warden of Stannaries,
54
Plans of mines, importance of preserving,
815
Perranzabuloe lead mine under the sea, Plat, Dr. Robert, History of Staffordshire,
407
99
Petrified wood, pseudomorphous, 492
Pettus on the mines at Talybont, 154
Sir John, "Fodinæ Regales," 125
on the Irish mines, 123
on Cardiganshire mines, 152
Phillips, J. A., analyses of Elvan, Clay,
""
""
""
""
99.
""
""
""
""
""
""
Granite, 367
contribution to the history of
veins, 372
experiments on lodes, 99
on hot spring in Wheal Seton,
9༠
on hot springs in California,
383
on waters of Cornish mines,
366
on thermic waters, 219
John, of Tuckingmill, electrical ex-
periments, 395
""
Phillips, Prof. John, on Derbyshire, 232
on lines of disturbance,
316
""
""
""
""
""
""
""
""
""
""
""
""
on the dependence of
minerals on the rocks,
312
on the Toadstones, 237
temperature at Monk-
wearmouth, 379
"The Geology of York-
shire," 245
"Thoughts on Ancient
Metallurgy," 41
on veins in Yorkshire, 244
on whin sill, 240
William, on lode or load, 284
""
117
Plat, tip-plat, 596
Plate, or shale, in Yorkshire, 246
Plates for sizing, perforated, 743
Playfair on trap dykes and veins, 483
Pliny on finding black lead, 22
""
""
""
on a law prohibiting the working of
"black lead," 22
on the alutiæ or gold streams, 22
on the production of tin, 6
Plot on the Staffordshire mines, 160
Plowden on stannary laws, 55
Plug and feathers, 657
Plumbago, 178
99
found in elvans, 209
Plumbum candidum, Pliny's name for tin, 6
Pneumatic engine, for underground hauling,
549
stamps, Husband's, 734
Poder, the name given to copper pyrites, 827
Polarity in formation of crystals, 301
Polberro mine stamps, 732
Polbrean lode, length of, 304
Poldory mine, temperature of, 377
Poldice, a great sum lost, 112
Polrose Wheal stamps, 732
Polytechnic Society and man-engine, 647
Pool mine, Newcomen's engine on, 111
Pool, R. S., on the Phoenicians and Canaan-
ites, 18
""
""
on the bronze image found in St.
Just, 15
Pool-East mine, electrical experiments in,
""
131
390
Wheal, near Helston, worked for silver,
on east and west lodes, 311 Pooley, Mr., discovers a mass of calamine,
Philosopher's wool, 132
Phoenicians, origin of the, 4
Phonolite, the Wolf Rock, 10
131
Popler, John, discovers a new silver mine,
129
Phosphate of lead formed recently in Wheal Porkellis Moor, tin in disintegrated Granite,
Rose mine, 270
Physical character of ores, 699
Picks, 712
Pick, Roman, found at Machynlleth, 40
Pickers and pokers, 657
mining, 655
Picking boxes, 712
349
Porringer of native Scotch gold presented to
Queen Elizabeth, 171
Porter, G. R., on the production of tin, 818
Pot grouan, very soft grouan, 86
Pott, his essay on zinc, 132
Potters' ore, or strontian, 274
Pig iron produced, value of, from 1620 to Precipitated copper, 833
1798, 176
Pipes of air to compressors, 517
Pipe veins, 287
Pisa received tin from Cornwall, 46
Pitch tribute, 107
Preparation of ores for smelter, 685
Pribram, Bohemia, boring machines and elec-
tric blasting, 535
Prices of English lead per fodder, from 1783
to 1800 (Appendix), 904
Prices of copper ore, 832
""
""
""
་
""
""
905
INDEX.
of English lead per fodder, from 1801
to 1828 (Appendix), 904
of lead at Grassington (Appendix),
903
of tin
ore and tin since 1854
(Appendix), 889
of tin, 1697, 56
of tin from 1783 to 1799, 77
of zinc ore since 1858 (Appendix),
Prideaux, Mr. John, on elvans, 485
Prime, Frederick, translates Cotta's work,
334
Primitive Granite, 202
Prince George vein, length of, 304
Processes, humid, 773
Produce of copper in Cornwall, 832
Production, cost of, in Alston, 583
Profit accruing on mines, 876
Profits on a mine regulated by its machinery,
868.
Pseudomorphism in minerals, 491
Pudrolythe, report on, 616
935
Pulverising action of pneumatic stamps, 736
Pulverising slimes, 737
Pumping engines in Cornwall, 626
Pumping engine, Cornish, 630
""
641
",
""
improvements of,
Pump-work and pumping, 865
Pyramidical troughs, 749
Pyrites, burnt cupreous, treating of, 775
copper in Cardiganshire, 321
cupreous, 833
""
""
""
found in dark blue slate, 202
""
importation of, 849
production of, 848
Pyromorphite in Cumberland and Scotland,
""
""
372
lead mines, 320
"Progress of the Nation," by G. R. Porter, Qupolas in Derbyshire, 147
818
Prospecting for lodes, 502
Providence mines, carbonas in, 407
mine, under the sea, So
""
Pryany lode, 290
Pryce, William, describes elvan, 206
QUA
UAKERS, a company of, introduced
Quarter-point veins, 244
""
"
وو
in Alston, 317
Quartz, double-headed, at Wheal Coates,
""
""
describes Jews' house, 17
"Of the Strata of the Earth,"
215
""
""
220
lodes, near Dolgelly, 265
reefs, 505
specific gravity of, 69
""
""
on accidental discovery of
on
""
""
""
""
""
""
""
""
""
35
""
""
""
""
33
mines, 500
a
tin miner going to RADIAL cut system of boring, 544
Saxony, 45
on dressing of ores, 689
on lapis calaminaris, 132
on lodes as fissures, 330
on first introduction of stan-
nary laws, 55
on metallic tin produce, 52
on principal contents of veins,
369
on production of tin, 68
Railways, guage of, in tunnels and
mines, 518
Rag and chain pump, in Pool mine, 564
Ragging dead frames, 769
""
sieve, 703
Ragman vein in Minera a caunter, 443
Railways in mines, 864
""
in tunnels or mine-headings, 517
Rainfall, table of, in Cornwall, 620
Rake veins, 286
Rampgill mine, deepest in Alston, 310
""
vein, discovered by Smeaton, 150
Ramsay, Sir Andrew, describes Turf copper
""
""
on shodeing, 501
""
""
on stamping-mill, 725
""
""
on the divining rod, 95, 96
""
""
on the steam engine, 87
""
""
on the term bal, 83
""
""
""
""
on working mines in 1700, 84
on working tin mines, 564
""
""
""
Pryce, Sir Carberry, works Welsh mines, 155
""
""
on veins of silver, lead,
and copper, 156
Pseudomorphs by alteration, 492
by substitution, 492
""
by incrustation, 492
""
""
of Felspar, 195
""
Wales," 324
""
mine, 121
on Snowdon, 263
on the rocks of Angle-
sea, 324
on Turf copper mine,
454
"The Geology of North
Raspe, Rodolph Eric, author of "Baron
Munchausen's Travels" (note), 103
Ratchel, rumel, or rubble, 233
936
INDEX.
Ray's "Itinerary," describes mines near Rodderup Fell, worked on Lower Lime-
Machyntllyth, 154
Raymond, Dr. R. W., on Hoefer's theory,
99
""
hypothesis, 672
""
stone, 461
map of, 462
672
remarks on Hoefer's
Roebuck, Mr., letter to Mr. Boulton, 113
Rogers, Professor, on mineral changes, 495
Roman Gravels, a Roman mine, 27, 256
level at Snailbeach, 28
""
""
""
""
""
Réaumur on tin plate manufacture, 60
Receivers, table of, 514
Record Office searched by Col. Francis, 88
Red Ash mine, Whaley, lead ore in, 259
River, produce of tin from, 824
Reddle found at Winford, 232
Redruth and Camborne district, length of
lodes in, 305
Reducing tools and machinery, 713
Registers of progress should be kept, 866
Reich, Professor, on electrical experiments,
394
Relistian mine, pebbles found in, 205
Renewer, the, a renewer of bounds, 56
Restormel iron ores, 808
Restronguet Creek, tin works on, 352
Results of working eighty-eight mines,
869
Returning charges explained, 680, 683
Revenue, charge of, Isle of Man, 162
Ribeira, Capt., uses the divining-rod, 95
Richard, Earl of Cornwall, held possession
of the county, 48
Richmond, Yorkshire, copper mine, 91,
828
Rickard, Dr., on copper ore ticketings, 682
"Miners' Manual," 678
""
""
Riddle, hand, 745
Riders, 289
Right veins, 244
Ringertz, or ring ore, formation on, 336
Rittinger's "Stausatz," 725
Robinson's "Early History of Keswick and
""
""
other Mines," 119
""
""
mines on Mendip Hills, 31
""
in Wales, 25
pigs of iron found in Britain, 36
remains in Monmouthshire, 43
found in Worcester, 174
""
works at Cinder Point, 174
Rosewall Hill Granite, 196
Rosewarne mine, brecciated lode, 421
Rose Wheal, near Helston, worked for silver,
130
Roskear mine languishing, 112
Rosler, Balthasar, "Speculum Metallurgiæ
Politisimum," 327
defines mineral veins,
""
333
""
Ross Island copper mine, 279
Rottenstone of Derbyshire, 234
Rouby, Dr., manufactures blue vitriol, 773
Roughtingill mine, 150
Rowe and Le Neve Foster on Balleswidden,
349
Rowpits, in the Mendips, worked by Sir
Bevis Bulmer, 153
((
"Rows" and "slimes," 789
Royal mines, Sir J. Pettus on, 125
how determined, 127
""
""
""
School of Mines founded, 89
Ruabon coalfield and lead veins, 442
Rupert, Prince, articles of agreement on mines
in Wales, 155
"Natural History of Cumber- SACK, measure of, 678
land," 91
Professor, employing Watt, 112
Rock-boring machines, daily rate of boring,
555
machinery, 507
99
""
""
plant of, 558
""
""
percussive characteristic, 568
organisation, 538
Rock masses, formation of, 218
375
temperature of in Comstock level,
Rocks, altered, Dr. la Beche on, 221
contorted at Boscastle, 220
dissimilar influence on lodes, 192
relation of to lodes, 399
and heaves, their relations, 670
influence of, on ore deposits, 199
nature of, 194
""
""
""
""
""
""
Safety governor, Husband's, 647
Salmon, Henry Curwen, on Botallack, 402
on boulders in lodes, 422
on continuous jigger, 695
Sampling and sale of copper ore, 679
""
""
""
of ore, 679
copper ores, 108
Sandberger, F., finds mineral ores in rocks,
366
Sandstone, Bunter, of Cheshire, 257
""
old red, Flintshire, 261
Sanntus, Marinus, on tin going to the
Levant, 47
Sarcens, or strangers, 1
Sardanapalus receives tribute from the Phoni-
cians, 4
Sarzeaud, researches on metals in sea-water,
361
Savery's, Captain Thomas, fire-engine, 88
Saxor. coins found near St. Austell, 45
chronicle on a legendary flood, 10
philosophers on mines, 327
""
Saxons in Cornwall, 817
INDEX.
Saxony producing tin, 7
Scarth, Prebendary, weight of pigs of lead, 35
Scawen, Mr., on the revenues from tin, 68
Vice-Warden of Stannaries, 60
""
""
Schistose Greenstone, 214
structure produced by cleavage
lamination, 302
Schmidt, of Siegen, on dislocation of lodes,
677
Scholl's stamps, 736
Shafts, called by various kinds, 569
described by Tonkin (1733), 73
in metal mines, 595
""
""
sizes of, 571
timbering of, 571
Shaft-sinking described by Pryce, 85
stand for boring, 522
""
Shale, limestone, 234
Shallee mines, 474
Shammeling described, 565
Shammels, plots or stages, 84
Shap Granite, Ward on the, 267
Sheet steel for skips, 597
lead used by Romans in tombs, 37
Schorlaceous Slates at Castle an Dinas, Shelf, or surface of rock, 502
221
Schutz, John, Warden of the Stannaries, 54
Scilly, Islands of, the Tin Islands, 9
Scorrans, small veins, 401
Scotland, copper mines in, 122
""
gold in, 169
""
""
""
""
Shelf-rubble, shode-stones, 499
Shelve, Shropshire, mines at, 232
937
Shoad or shodes, Carew describes, 63; des-
cribed by Dr. Borlase, 75
Shot-holes, boring of, 540
Shovel, for dressing ores, 712
mineral veins described by Williams, Shovels and spades, 656
273
mining in, 267
records of mining, 162
lead ore produced since 1845
(Appendix), 902
Scott, of Douglas, on the mines at Brada,
162
Scovan lodes, lodes containing gossan, 491
Scrapers for boring, &c., 652
66
Scrins," stamp, 237
Scylax, the Periplus of, 8
Sealhole mine, heaves in, 293
Secondary and primitive granite distinguished,
202
Section of the Consolidated mines, 599
"Section of Strata," Forster's, 465
Sedgwick, Professor, on Carclaze, 417
Shrewsbury lead ore found at Ribden, 160
Shropshire lead-bearing district, 253
""
Roman mining in, 27
Shute, Christopher, grant of Queen Elizabeth
to, 126
Side mine, Derbyshire, 243
Sienetic Greenstone, 214
Sienites of central England, 234
Silicates, Sandberger examines for, 366
Silver cup from Beer Alston, to the Earl of
Bath, presented by Queen Elizabeth, 128
Silver in gosans, 490
""
in Scotland, 273
in ships' copper sheathing, 364
mines, Ireland, 474
near Killaloe, 279
native, in Cronebane, 471
""
""
""
""
""
""
on divisions in rocks,
223
""
""
""
""
dale, 311
on the lead and zinc ores
near Coundon, 251
traces a fault in Tees-
Segregation of mineral matter in lodes, 346
veins of, Sedgwick on, 418
""
Self-stones in Derbyshire, 233
Separating machinery, 792
Separator, Brunton's, 696
Serpentine rock, 217
Serpent-worship of the Phoenicians, 4
Seton Wheal, mineral water from, 367
Set or moil for cutting ground, 655
Setting a copper mine, 107
Severall, law relating to, 55
Carew describes, 65
""
Severn Tunnel stand, 521
Shaft, construction of, 572
ore dressing, 700
first discovery of in Cornwall, 801
,, production of, ore, 836
•
,, separated from lead by the Romans, 25
""
""
""
pyrites, 849
"Silurian System," Murchison's, 253
Simpson & Co., trial of their engines, 638
Simpson's, James, valve, 631
Sims's, Mr., engine, 638
Sizing apparatus, 742
""
importance of, 705
plates, table of, 743
Skiddaw Granite, 250
Skips, 596
""
""
filling of, 597
loading of, 599
Slab, Roman copper, found in Anglesea, 38
Slag-mills, hearths, blown by bellows, 146
Slate and sandstone, Werner's definition of,
332
•
938
INDEX.
Slate of Derbyshire, 234
""
""
""
""
inferior, of Conybeare, 213
rock around Carn Marth, 202
superior, of Conybeare, 213
water pumped from, 623
Slates, schistose, Henwood on, 204
Slickensides, in Derbyshire lead mines, 143
Sliding gravel in Derbyshire, 233
Slidy ground in Wheal Mary Ann, 433
Slime or buddle jigger, 763
Slip veins, 289
Slither, rubble of Limestone, 233
Smalts made at Alderley Edge, 192, 259
Smeaton discovers Rampgill vein, 150
""
the engineer, receiver of the Free-
mond Hospital Estate, 150
Smelter's profits, 681
Spain, early metal works in, 3
Sparre, Von, on the art of dressing ores,
690
Spathic iron ores, 797
Spathose iron ores on Brendon hills, 231
Specific-gravity balance, 697
bottle, 697
Specific gravity of common ores (Appendix),
""
""
""
""
""
39
་་
pendix), 886
885
of gangueiferous minerals
(Appendix), 886
of metals (Appendix), 885
of ores, 698 and Appendix
of precious metals (Appen-
dix), 885
of veiniferous minerals (Ap-
Smelting lead ore in Derbyshire boles, old Spheres and grains, terms in dressing ores, 703
lead hearths, 146
Smiddum, rough ore, 690
Smith, Dr. George, on tin trade, 818
Smitham, a variety of lead ore, 145
Smittergill Head lead mine, 462
Smyth, W. W., of changes in direction of a
""
""
""
""
""
""
""
123
""
""
""
""
","
""
shaft, 570
on dressing ores in Cardigan-
shire, 691
on Gogofau or Ogofau gold
mine, 43, 168
on mineral veins in Cardigan-
shire, 321
physical phenomena of mines,
204
on productive lodes in Cardi-
ganshire, 253
on Roman level at Cwm-
ystwyth, 38
on shafts in Wales, 582
on the occurrence of lead ore,
855
on timbering, 571
""
""
""
""
on Wicklow mines, 473
"2
on Wicklow, 275
Snailbeach lead mines, 255
Soap-stone near Mullion, 218
"Solestone," to a vein, 237
Solfataric action forming mineral ores, 373
Somersetshire mines, 230
Roman mines in, 31
Sopwith, Thomas, on the "Back-bone of the
""
""
""
""
""
33
""
""
Earth," 457
on dressing lead ores, 690
on Maiden Way a military
road, 148
on vein throws, 313
on veins in Yorkshire, 244
Sorby on water in Granite, 195
Southwell, Sir Robert, on an old lead pit,
137
""
fall of, in water, 706
Spikkaster, a separator, 696
Spring stamps, 729
Square-cut system of boring, 543
Squinting of veins, Werner on (note), 243
Squire Wheal added to United mines, 427
Staffordshire copper mines, 160
""
and Derbyshire mines, 116
Stahl, G. E., theory of veins, 327
Stamping machinery, 724
""
""
mill, advantages of, 728
ores, cost of, 727
Stamps compared, 866
""
steam direct-acting, 733
Standard of copper, 832
copper ore, 680
Standards of ore, 685
""
true, to calculate, 683
Stand and trolly for borers, 521
Stands and frames for boring machines, 518
Stannaries declared a royal demesne, 50
Stannary Court, originated in the time of
Athelstane, 48
Parliament allowed to frame their
own laws, 51
Stanniferous Granite in Ding Dong Mine,
351
Stannified Granite burnt as tin stone, 76
Stanley, Hon. W. Owen, on Roman remains
in Anglesea, 37
Stanton, Mendips, copper found, 231
Stapleton, William, rents the mines of Alston
Moor, 148
Statice armeria grows at Turf copper mine,
455
Steam engines for boring, 509
""
""
trial of, 638
stamping-mill, Woolf's, 725
stamps, 732
Steatite in Serpentine, 218
Steel for borers, tempering of, 652
INDEX.
Stein, W., speaks of paramorphism, 493
Steinburg, Mr., a German miner, 93
Stephenson, A. L., report on explosives,
615
Stockwerke, Warner's definition, 332
Stokes, Professor, on fluorescence, 480
Stone breakers, 716
Stonecroft mine, near Haydon Bridge, 344
Stone grinder, Marsden's, 721
""
waterworn, found in South Wheal
Frances, 422
Stopeing overhand and underhand, 602
Storose, drawing apparatus, 141
Strabo describes the Cassiterides, 9
""
on iron mines, 43
Strait iron ore mines, 809
Straits Settlements, tin from the, 821
Strata veins, 288
Stratigraphic system, 297
"Stream Tinner," his selection of tin ground,
69
Stream works around St. Austell, 354
Streaming described, 69
Strech vein, 288
"Striking deals," penthouses in shafts, 595
Strings of oxide of tin in slate, 347
Strontian found in Gloucestershire, Somerset-
shire, &c., 186
""
rocks of the mining field, 274
Stuff, division of, for dressing, 709
وو
""
dressing of, 703
removal of, before blasting, 550
tin of, cost of reducing, 722
Sturmy, Captain, on old lead ore pit in
Gloucestershire, 137
St. Agnes clay pits, and old sea-coast, 204
strings of tin in Slate of, 347
St. Austell district, lodes, 303
St. Gothard, bore-holes used, 547
";
tunnel, compressors used, 512
St. Hilary Church, Roman remains in, 24
St. Issy mine, near Padstow, 130
St. Ives, Greenstones at, 214
""
Consolidated mines, 405
St. Just, map of mining district, 401
St. Leven, Land's End, 205
St. Michael's Mount probably the Iktis, 12
Sublimation, influence of, 348
""
""
Nicker's views on, 336
of minerals, 345
theory of mineral veins, 396
"Subsist," Cornish practice of, 684
Subterranean surveying, 659
""
""
temperature, 611
working, 561
Suggestion on mining, by a miner, 863
Sulphur an important mineralising agent, 340
Bank a mercury mine, 373
veins of Alston, 312
""
Surface force in veins, 303
Survey, to conduct a, 667
939
Surveying, instructions for commencing,
663
Surveying, rules for, 664
Sussex Iron Works, 176
Swab, Van, taught the Swedes to extract zinc,
133
Swaledale, lead ores in, 246
""
""
mineral lodes in, 318
mines, produce of, 468
Swanpool, Budnick, produces calamine, 126
Swansea smelters from 1717, 101
Swords, daggers, &c., found in peat bogs, 15
Syenitic Granite, 250
Symdda Dylluan Copper Mine, 263
Symons, G. J., on rainfall, 622
ABLER and buddler, 764
Tables used by mine accountants, 685
Tacitus's "Life of Agricola," 24
Tailings, loss in, 702
Talc schist, 217
Talybont, mine at, 154
Tarshish merchants, 2
Taylor, Dr., discovers malachite in granite,
468
Taylor, C. H., on stream works in Restronguet
creek, 358
Taylor, John, his influence on mining, 872
improvements in dressing ores,
688
""
""
""
""
""
""
99
པ
39
improves crushing mill, 693
on a school of mines, 871
on Duck machine ventilator,
612
on Milltown lead mine, 166
on payment for dead work, 585
on silver produce, 837
on transport of ores, 697
on Woolf's engine, 629
""
""
""
""
""
";
on vein-stones, 457
""
""
""
"
""
""
report on mineral veins, 483
works Restronguet creek, 352
Sir William, comptroller of a com-
mission on mines, 151
Teague, Mr. Wm., ventilator, 614
Teesdale mines, 463; 467
Tees-side, strata of, 247
Temperature at different depths, 610
increases with depth, 377
lodes with different ores, 378
mines in Granite and Slate, 378
of flues in Cornish engines, 642
of mines in depth, 608
rocks, cross veins and lodes, 378
subterranean, 376
""
""
""
""
940
INDEX.
Temporary bottom, Kind-Chaudon system, | Tin, produce of, in Cornwall and Devon from
589
Theodolite, its use, 659, 661
Theoretical and practical mining, 189
Thermal water, W. W. Smyth on, 375
Thermic resistance, 509
Thomas, Captain Charles, tin table, 679
1818 to 1837 (Appendix),
887
in Cornwall
""
""
since 1750
(Appendix), 887
818
""
""
""
""
""
وو
""
on the zone of pro-
ductive mines, 199
on productive lodes,
438
""
""
Mr., drainage of Fowey River, 617
""
99
""
,,
""
""
""
""
""
""
29
609
وو
drainage system of Gwennap,
619
map of mining district, 618
on Carclase mines, 417
on Carnon Stream, 352
on soft and hard elvan, 211
Mr. William, experiments on Cook's
Kitchen, 381
Josiah, on Dolcoath Mine, 850,
435
on temperature in Dolcoath,
Thon Schiefer, or Argillaceous Slate, 215
Thornhill, Bache, of Staunton, on the Peak
lead mines, 145
Thousand years' lease, 149
Throw of veins, 291
Thurland, Thomas, a German miner, 91
Thyrlings in collieries and lead mines,
294
Ticketing of copper ore, 680
Ticketings, copper ore, 679
Tick holes, cavities in the lode, 289
Tigroney, copper ore and pyrites, 276
Tigroney, produce of, 473
Till bed in Cumberland, 248
Timber, preservation of, in mining, 574
Timbering in Derbyshire, 578
""
cost of, 575
Time and speed of boring shot-holes, 551
Tin bounds of North Downs, 53
""
""
consumption of, in Britain, 818
detrital, 204
,, exported to various countries (Appen-
dix), 890
""
33
""
""
""
>>
""
farm of, Cornwall, its value in John's
reign, 48
floors, John Hawkins on (note), 405
in the Scilly Islands, 11
in Wicklow, Mr. Weaver on, 468
Island of the ancients, 2
measures of, 678
mining, progress of, general statement,
822
ore and metallic tin obtained since 1848
99 99
(Appendix), 889
diffusion of, 348
""
production of, from five hundred years
before Christ, 823
pyrites, analysis of, 405
shipped from Cornwall for China (Ap-
pendix), 890
stone, sampling of, 778
, stream, its specific gravity, 69
""
وو
""
streams, production of, 824
rivers and foreshore, 358
supplied on the stocking system to East
India Company (Appendix),
891
""
""
""
""
""
""
""
by the miners to the East India
Company, 77
tables (Davey, Provis, &c.), 683
trade of Cornwall from 1750 to 1799
(Appendix), 888
56
in 1780 (and note), 81
in Cornwall, historical sketch of,
by William Copeland Borlase,
16
proposal for the improvement of,
traffic in, 816
where found (W. Borlase), 498
Ting-Tang mine has a Watt's engine, 113
Tinn-Wald, Isle of Man, 325
Tintagel Castle, Slate rock of, 216
Titanite, report on, 616
Toadstone, decomposition of, 238
""
""
section of, by geological survey,
241
the, of Derbyshire, 236
Toller office established, 52
""
the collector of bounds tolls, 56
Tol-peden, Penwith, 205
Tomb, Roman, found in Monmouthshire, 37
Tonite, 529
99
report on, 614
Tonkin on mine shafts in his time, 73
""
quotes Carew on gold in Cornwall,
167
Thomas, Mr., on introduction of
gunpowder, 67
Tools and drills for boring, 527
Tossing and packing tin ore, 778
Tram-waggon, 712
Tramways, 712
Transfer of power, apparatus for, 636
Transit instrument, 665
Trap rocks, intrusive, 213
""
""
of Durham, 240
Trapean, or Greenstone rocks, 212
INDEX.
Trathan, Richard, a Cornish miner, improves | Tunnels and boring machinery, 515
lead ore dressing, Alston Moor, 150
Trebra, Von, quoted by Werner, 331
Trees and branches found in veins, 483
Tregembo, Husband's stamps at, 736
Tregilliow, diffusion of tin, 348
Tregoning Hill Granite, 201
Tresavean, experiments on steam engines,
201, 641
""
""
mine, temperature at, 379
""
""
of, 384
Turbery, a turf field, 445
941
Turf copper mine, Merionethshire, 121, 263,
454
"Twitched-up" veins, 238
Tyddyn-Morgans, old mines on, 39
Tyne-Bottom Limestone, 249
""
yield barytes, 482
Types of stamping machinery, 729
Trevaunance beach, St. Agnes, Killas cliffs, ULV
216
Trevithick, Richard, sen., manager of Dol-
""
19
""
""
""
""
""
•
coath mine, III
at Dolcoath, 109
jun., converted plunger-
pole into a prime
mover, 115
employed at Stray
Park mine, 115
erected pump-rods
at Prince William
Henry mine, 115
erects steam engine
at Wheal Treasury,
626
examined
""
""
""
""
""
"9
""
""
""
""
""
""
pole, 115
""
Watt's
engines, 627
first inventor of
JLVERTON, hæmatite mines near, 161
Underlie and perpendicular of lodes,
(Appendix), 886
Underlier, an underlying shaft, 85
Underset chart in Yorkshire, 246
United Kingdom, copper produce in the, 831
mines, elvan courses in, 211
""
""
""
29
834
incorporation of, 427
States of America, copper produce,
Unwatering mines, 618
Upcast strata, 245
Uranium, found in Cornwall, 185
ALUE of ground, 683
VAL
Valve, four-beat, Husband's, 629
Valves, Hornblower and Woolf's, 627
Van, the, mine, 487
shaft-boring ma- | Vanadinite at Wanlock head, 372
chine, 522
introduced plunger-
Trewavas mine under the sea, 80
Tribute, cakes of copper, Roman, 38
""
setting a copper mine on tribute,
107
system, 861
working recommended, 873
Tributor, his dole by agreement, 107
Trigar, Mr., his system of sinking shafts,
589
Trolly, with platform for carrying machine,
520
conical, 746 ·
""
double, 746
""
single, 744
cylindrical, 746
""
sizing, 714
Trommel, clearing, 714
Trommels, sizing, for sorting ores, 696
""
sizing, table of, 744
""
speed, &c., table of, 747
Troughs, double triangular, 751
Troughton's continuous jigger, 695
Troutbeck, strata of, 247
Troy, tin used at, 5
Tuftill, in Cumberland, 248
Vanning shovel, 654, 710
Variation of the needle, 656
Vegetables, silver found in them, 362
Vein, large, in Strontian, 274
"9
stuff of Derbyshire miners, 238
Veins, decomposition of contents, 344
""
""
""
""
""
""
""
""
""
""
""
""
""
definition of, 283
designation of in Yorkshire, 244
distinguished, 286, 288
division of by Whitney, 342
in Minera mines, 439
length of, 304
named, 284, 285
of Alston Moor, classified, 312
production of Snailbeach, 256
rake, 286
rights, quarter-point cross, 244
six o'clock and the like, 286
way of finding, 500
Werner's definition of, 332
Venetian grievances, &c., 56
Venice received tin from Cornwall, 46
Ventilation after blasting, 548
artificial, 605
natural, 605
""
""
in Tincroft mine, 612
""
""
of mines, 605
Vieille Montagne, zinc in Dolomite, 364
942
INDEX.
Vigra and Clogau, copper and gold found, | Wanlock Head, mineral veins of, 268
""
263
worked for copper, 122
Vincent Dean, commerce and navigation, 2
Vipond, Nicholas, had royal protection for
working mines, 148
Virgin Wheal, unprosperous working, 112
Virgula Divinatoria, 94, 498
Virlet, M., found a gryphæa in lead mine,
423
Vivian, Andrew, high-pressure engine, 626
Boulton, and Williams write a letter
""
on the copper trade, 116
Volumetric sizing, 703
Von Decken on Carclaze Mine, 417
Vor Wheal mine, 413
re-worked, 415
underlie of lodes in, 415
Voughs or Vugs in the Gwennap lodes, 425
""
of great size, 486
WAGGONS for underground, 598
Ward, the Rev. J. Clifton, on the geology of
the Isle of Man, 266
Wardenists and anti-Wardenists, 76
Warwickshire, manganese in, 184
Washing apparatus, 713
Wash-kilns, 713
Wass, E. M., on Derbyshire lead mines,
481
""
Wasterell grounds, law relating to, 55
Wastrell, Carew describes, 65
Water ascending through fissures, 348
and ventilating apparatus, 528
circulation of, in veins, 344
descending in fissures, 348
flowing from hot spring, 377
from Phoenix mine analysed, 380
from Dolcoath mine analysed, 381
""
""
"
""
""
""
power required for stamps, 728
pressure engine, Tevithick's, 625
Watson, White, "Delineation of the Strata of
Derbyshire," 238
Watt's engine, introduction of, 113
Waldegrave mines on the Mendip Watt, James, employed by Professor Robi-
Hills, 31
Wales, Central, mineral district, 253
Wales, North, report of mines in, 310
Wallace, Wm., on Alston Moor mines, 459
""
""
""
""
""
""
""
on barytes in Dufton mines,
481
on cross veins, 317
on Dufton lead mines, 462
on lead veins in Alston Moor,
343
""
>>
son, 112
on his commercial success in Cornwall,
114
patented an expansive engine, 112
Weardale, iron ores of, 795
mines, 466
Weaver, Thomas, geological relation of the
east of Ireland, 468.
on a brecciated lode, 469
on gold in Ireland, 276
""
""
""
""
""
""
on metal-bearing rocks, 854
""
on Lachamore, 280
""
""
""
on tin in Ballinvally stream,
""
""
on Rodderup Fell veins, 461
""
""
""
on mineral veins, 395
on the formation and direction
of mineral veins, 314
Waller's account of Cardiganshire mines, 153
accounts to the Mine Adventure,
""
156, 157
Waller, agent for Sir Carberry Pryce, 155
on Bushell's mining, 154
""
""
""
on the Mine Adventure, 156
petitions House of Commons, 158
Wallerius, J. G., on mineral veins, 330
Walling end of gallery, 583
""
shafts, 575
Walls of a mineral lode rarely parallel, 302
Wallsingham, Sir Francis, secretary to Queen.
Elizabeth, 93
Walter Fitz-Walter commanded by Henry IV.
to inquire as to a gold mine in Essex, 167
Walton, Adam, Moormaster of Alston, 150
& Co. bought a mine at Nenthead,
150
""
""
457
John and Jacob, on Alston Moor,
""
470
on veins in Dolomite, 131
Wedge for blasting holes, 651
Weights for copper assay at Dolcoath,
677
""
Welsh bullion minted at the Tower, 152
miners, rules observed by, 322
Wendron, south district, Dr. Le Neve Foster
on, 409
Werner, Abraham Gottlob, classification of
""
""
""
""
""
""
""
""
""
""
""
""
""
""
""
lode, 478"
33
processes, 561
follows Rosler,333
"New Theory of
the Formation of
Veins," 331
on
deposits in
veins, 483
on Elvans, 209
on Killas, 215
on symmetry of
veins, 243
on Segen-Gottes
INDEX.
Werner, Abraham Gottlob, quotes Von Oppel | Williams, John, on Isle of Islay, 272
with approval, 328
West and Darlington, counterbalancing
pump-rods, 634
West's, William, steam engine, 648
""
""
""
""
""
""
appointed engineer at Fowey
Consols, 633
high-pressure engine, 628
as a working engineer, 633
& Petherick's boilers, 635
Westbury iron ore, 806
Westdale Granite, 250
Westmoreland, 246
""
وو
mines, 467
""
notes on, 345
Weston, Mr., describes old working
Machynlleth, 40
on Strontian (1789), 274
on veins, 290
""
""
on Lossimouth, 272
""
""
""
""
""
""
Records of Denbigh, 39
943
Thomas, to Lord Uxbridge, on
the Anglesea mines, 104
Wilson, Bishop, "History of the Isle of
""
field, 266
""
Man," 162
on the Clay-slate of Sna-
Wilton's improved dial, 661
Wiltshire (Seend) iron ores, 806
Windesor, Mr. Thomas, his mines on Men-
dips, 36
at Wind-hearth, for lead-smelting, 146
Winding engines, duties of, 648
Weston's, Mr., German miners, 89
Whaley, section in lower coal measure,
209
Wheelbarrows, 712
Wheeler's "Geography of Herodotus," 2
Wherry mine, elvan course in, 210
the, tin mine, 77
""
Whetstone sill, 247
Whimsey shafts, depth and cost, 580
Whin-sill, 239
""
of North of England, 237
Whiston copper works, 118
Whitaker's "History of Manchester" on tin
in Scilly Islands, II
Whitby, Henry de, and his wife, disputes
with the miners, 148
Whitehaven iron mines, 804
Whitley, N.," History of Mining," 66
""
C. E., section of tin deposit, 352
Whitney, J. D., metallic wealth of United
""
"
""
rals, 345
States, 343
on mineral veins, 395
on the sublimation of mine-
Wicklow and Wexford mines, 468
""
W. W. Smyth on, 275
Wickstead on the steam engine, 642
Wildberg mines, transfer of power at, 636
William, Captain, on the Van Mines, 488
J. Michael, has gold found in Corn-
wall in his collection, 168
""
Mr. Michael, on Elvan courses,
211
the Conqueror grants the earldom
of Cornwall, 47
Thomas, on the Parys mine, 122
Williams, John, describes lodes in Alston
Moor, 458
""
""
""
""
steam, 647
Winford, geology of, district, 232
Winze kibbles, 596
Wires, conducting, 535
""
connecting, 536
Wire ropes, weight, tenacity, &c., 592,
593
Witt, Mr., on filtering the water of the
Thames, 219
Wolf Rock, formerly a rock basin (see Gulf),
3, 9
""
Wolves' Fosse, supposed Roman, 39
Wooden spades found in Cornwall, 30
Roman mines, 92
Woods recommended for mines, 575
Woolf, Arthur, a workman under Trevithick,
116
engines, 626
""
""
""
""
""
""
""
""
""
""
improvements in boilers, 631
progress of, 628
specification for engine, 633
wrought-iron boiler, 628
Work executed by boring machines, 553
Working a metallic mine, 600
""
in Gwennap mines, 431
in the load mines, Carew, 64
Worth of lodes at different depths, 311
Wright, Lawrence, finds lead and copper on
Alderley Edge, 258
""
""
Thomas, on copper veins worked by
the Romans, 37
on Roman mines, 27
Wrothan, Warden of the Stannaries, 50
Wymundham, William de, on silver raised in
Devon, 130
"Natural History of the YARRANTON, Andrew,
Mineral Kingdom," 270
on Cwm-ystwith lead mine,
360
""
manufacture, 60
on Roman
cinders, 173
on tinplate
944
INDEX.
Yates, Mr. James, "Mining Operations in | Zinc, “black jack" in Scotland, 275
Britain," 37, 41
Yellow Limestone, 236
Yoredale beds, section of, 235
imports and exports from 1823 to
1858 (Appendix), 905
in Derbyshire, 235
""
""
in Cardiganshire, 320
Yorkshire, ancient mining in, 26
""
mines in, '161
""
""
in United Kingdom, 841
""
mining tracts of, 311
""
""
ores found in, 244
ZIMMERMAN, C. F., on the formation
""
""
sures, 669
of minerals, 328
on faulting fis-
""
""
mining, 831
obtained from 1856 to 1882 (Ap-
pendix), 904
on the Mendips, 231
was it known to the ancients? 132
Zone, metalliferous, 851
""
of mining in the Granite of Cornwall,
199
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