UNIVERSITY OF CALIFORNIA
AT LOS ANGELES
THE
CHEMISTRY AND METALLURGY
OP
C OPPER,
INCLUDING A_DESCRIPTION OF THE PRINCIPAL COPPER MINES OF THE
UNITED STATES AND OTHER COUNTRIES,
THE ART OF MINING AND PREPARING ORES FOR MARKET,
AND THE
Various graces of fljjoppur mdtm#, &c.,
BY
A. SNOWDEN PIGGOT, M. D.,
ANALYTICAL AND CONSULTING CHEMIST, MEMBER OF THE AMERICAN ASSOCIATION FOE
THE ADVANCEMENT OF SCIENCE, OF THE AMERICAN MEDICAL ASSOCIATION,
AUTHOR OF DENTAL CHEMISTRY AND METALLURGY, 4C. 4C.
WITH ILLUSTRATIONS.
PHILADELPHIA:
LINDSAY AND BLAKISTON,
" 1858
8834 5
Entered according to the Act of Congress, in the year 1858, by
LINDSAY AND BLAKISTON,
in the clerk's office of the District Court for the Eastern District of
Pennsylvania.
BHRT B. ASHMKAD, BOOK AHD JOB PRIHTEI
George Street above Eleventh.
TH
ISO
CAMPBELL MORFIT, M. D., CHEMIST,
THIS WORK IS INSCRIBED
BY HIS PBIBND,
THE AUTHOR.
PREFACE.
Having been engaged for some years in the analysis of ores
of copper, and in the determination of chemical questions con-
cerning that metal, in connection with a large and well-ap-
pointed smelting establishment, the author has acquired ex-
perience which he has thought might be of service to others
engaged in the same pursuit. He has also been led to believe
that some information, in a form accessible to the masses of
our people, on the subject of mines, veins and ores of copper,
with the known laws of their occurrence, might be of service
in assisting in the development of this very important part of
the mineral wealth of our country.
The present work is designed to supply what the author be-
lieves to be a desideratum. His aim has been to popularize
it sufficiently for the use of those who have not hitherto made
the sciences of chemistry and geology a special study, with-
out so neglecting details as to render it of no value to the ex-
pert in these studies. How far he has succeeded in this at-
tempt is for the public to judge.
In the chapter on Mining, the author has endeavored to
present as complete an account of the various copper regions,
i*
yi PREFACE.
as was possible in the limited space of a volume like the pres-
ent. In treating of foreign mines, it has not been intended
to give anything like a minute description of them, but simply
to present to the reader a sketch of their geology and general
results, sufficient for the purposes of comparison with our own
mining regions. In reference to the mines of the United
States the author would say, that he has endeavored to em-
body the latest information accessible to him. Those who
have attempted to collect similar statistics, are aware of the
difficulty of obtaining reliable information, and will pardon
any omissions they may detect.
In the chapters on Smelting and Assay of Ores, the object
has been to define the principles on which the processes are
based, and to describe with clearness and precision, the various
methods by which the results are proposed to be attained. It
is to be hoped, that in this, as in the other departments treat-
ed upon, the work will be found sufficiently full and accurate
to serve as a guide to those engaged in adding to the world's
production of copper.
A. SXOWDEN PIGGOT.
40 BOLTOX STREET, BALTIMORE,
January 20th, 1858.
TABLE OF CONTENTS.
CHAPTER I.
CHEMICAL RELATIONS OF COPPER, 25
CHAPTER II.
ORES OF COPPER, 68
CHAPTER III.
ANALYSIS OF COPPER ORES, . . 90
CHAPTER IV.
MINES AND MINING, . . 143
CHAPTER V.
MINES OF COPPER, 193
L-
viii TABLE OF CONTENTS.
CHAPTER VI.
COPPER SMELTING, 286
CHAPTER VII.
ALLOYS OF COPPEE, 349
APPENDIX, 380
ERRATUM.
Page 215, 2d and 3d lines from top, " Cope'' 1 should read "Cobre."
INDEX
PAGE
Acetates of Copper - 61
Basic - - 62
Bibasic - 63
Hyperbasic - - ib.
Neutral - - 61,66
Sesquibasic - - - 63
Tribasic - ib.
Adit level - - 173
Adventure Mining Company - - 247
Agate Harbor Mining Company .... 229
Albion Mining Company - ... 243
Alloys of Copper - - - - 349
America, production of - 384
Ammonia-sulphates of Copper - - - 57
Ammoniated Copper ------ ib.
Amphid salts -------48
Ann Phipps Mine - - - - - -270
Antimony, detection of, in copper ores - 96
Aphanesite - 89
Arcot - 357
Arsenic, detection of, in copper ores - - - - 96
Arsenites of Copper - - - 63
Atacamite - ----- 73
Aurichalcum - - - - - - -351
Aztec Mining Company - 247
Azurite -------85
INDEX.
PAGE
Bare Hill Mine
265
Barnhardtite - -
78
Barrel work - -
227
Basalt
- 147
Bath metal
355
Bearing -
- 157
Bell metal - ...
- 373
Binoxide of copper -
39
Black oxide of copper -
72
Blistered copper
325
Blue metal -
317
vitriol -
- 51,87
Bohemian Mining Company -
- 247
Borate of copper
60
Boro-fluoride of copper
47
Bournonite -
83
Brass - -
- 350
Bristol -
- 355
solder ....
- 356
Bridgewater Mine
- 282
Bristol Mine - ...
- 258
Brochantite - ...
87
Bromate of copper ...
61
Bromide of copper -
46
Bronze -
355
Bruce mine - ...
- 254
Brunswick green -
45
Burra-Burra Mine -
208
Calcination, chemistry of -
296
Calciner
Cannon metal -
- 371
Canton Mine -
- 279
Cantonite - ...
76
Carbonates of copper -
60
Chalcotrichite -
71
Chemical relations of copper -
25
INDEX. xi
PAGE
Chlorate of copper - - - - 61
Chloride of copper ------ 44
and ammonium - - - - 46
potassium ----- ib.
hydrated - - - 45
Chrysocolla (alloy) - - 353, 355
(ore) - 84
Clarendon consols - - - 213
Clark Mining Company - 229
Cliff Mine - - 237
Coarse metal - - 303
Cobre Mines - - 215
Cocheco Mine - - 279
Condurrite - - - - - 81
Connellite - - 87
Consolidated Mines - - 209
Contra lodes - - - - - - -165
Copper, action of atmosphere on - - - 30
antiquity of manufacture of - - 25
application of to analysis - - 29
assay of - 123
by dry way, apparatus for - - - 123
of ores of first class - - 125
second class - - 129
third class - - 138
fourth class - - 139
roasting in - - 131
with cyanide of potassium - 136
nitre - ib.
by humid process - 137
Rivofs plan - 138
chemical characters of - - ' - 26
commercial - - - - - -28
purification of - - 29
cupellation of - 139
detection of, in ores - - - 92
determination of, by caustic potash - - 102
metallic iron - - - 105
Xll INDEX.
PAGE
Copper, determination of, by metallic zinc - - 106
sulphureted hydrogen - 109
Cassaseca's method - - 109
Level's method - - - 107
Pelouze's method - 109
estimation of - - - - - - 102
etymology of- - - - - -25
fusion point of - - - - -27
glance _-._._ 74
method of obtaining it pure - - 29
native - - - - - 68
ores, qualitative analysis of - - - - 93
quantitative analysis of - - 102
smelting of - 286
oxidation of - - - - - - 30, 33
facilitated by fat - - 31
recovery from alloys - - 378
separation from antimony, arsenic, tin, platinum, gold,
iridium, &c. - - 122
bismuth - - - 112
cadmium - - - - 116
cobalt, nickel, zinc, iron, manganese, 117
Berthier'g method 120
gold - - - 121
lead - 113
mercury - - - - 115
nickel and zinc, Flajolot's plan - 119
silver - - 114
zinc, Hautefeuille's plan - - 121
specific gravity of - - - - 27
uses of ------ 68
volatilization of - - - 28
Copper Falls Mining Company - 229
Cornwall, geology of- - - - - -194
production of - 382
Covelline - _ _ - 76
Cranberry Mine --_.-_ 269
Cross courses ------- 157
INDEX. Xlll
PAGE
Cuba, production of -
Cupric acid -------84
DaltonMine - - 271
Devon consols - 200
Digenite - -76
Diniodide of copper - - 47
Dioptase - - 84
Dolcoath Mine - 200
Dolly Hide Mine - - 262
Domeykite - - - - - - -81
Douglass Houghton Mine - - - 246
Drift - - 177
Dutch foil - - 355
Eagle Harbor Mining Company - 229
Erinite - 89
Erubescite - - 77
Euchroite - - 88
Fahlerz - 81
Flemington Mine - - 282
Fluckan - 197
Foot wall - - 157
Franklin Mine - 282
Fulton Mining Company - - 243
Furnace for smelting ------ 300
Gangue - 161
Gap Mine - - 261
German chest - - 188
silver - 358
Gilding metal - 352, 355
Gneiss - - 147
Gold, detection of, in copper ores - - 92
Gossan - - - 171
Granite - - - 147
Gray copper - - - 81
Great Britain, production of - - 384
2
XIV INDEX.
PAGE
Green candies poisonous - 67
Hade - - 157
Hanging wall - - ib.
Hard metal - - 316
Harrisite - -75
Hiwasse Mine - 277
Horse - - 162
Hydride of copper - - 40
Hyposulphate of copper - 58
Hyposulphite of suboxide of copper - - 49
Hyposulpkophosphite of copper - 67
Indigo copper - - 76
Iron City Mining Company - 234
Isabella Mine - - 278
Isle Royale, geology of - - - 243
Kapunda Mine - 209
Keweenaw Point, geology of - - 223
Mining Company - - 234
Lake copper, smelting of - - 286
Lake Superior Copper Region, geology of - - 220
Lavas - - 148
Lead, detection of, in copper ores - - 90
Levels - 177
Lettsomite - 88
Libethenite - - ib.
Lodes - 157
London Mine - - 278
Maillechort - - 359
Malachite - 86
Manassas Gap Mine - - 265
Manitou Mining Company - . 254
Mannheim Gold - - 355
Mary's Mine - r r - - - 278
INDEX. XV
PAGE
Masses - 227
Medals - 368
Mine La Motte - 215
Mineral Hill Mine - - 264
Mineral Point - -254
Mineral veins - - - 150
alluvial deposits - 150
contact deposits - 153
disseminated in eruptive rock - - 152
eruptive masses - ib.
fahlbands - 154
origin of - 166
regular deposits - 156
stockwerke - - 153
stratified beds - 151
Mines and Mining - - - - 143
of Algeria - - 207
Argentine Republic - 213
Atlantic States - - 256
Australia - - - - 208
Austria _-_.-- 203
Britain - - 194
Canada - - 254
Carrol County, Virginia - - 267
Chili - - - - 210
Cuba - 190
France - - 202
India - 207
Italy - 203
Jamacia -.__-_ 213
Japan - 207
Lake Superior - - 216
history of - - ib.
Mississippi Valley - - - - 253
New Jersey - - - - 280
Norway and Sweden - 205
Peru - 209
Prussia - - - - - - 202
XVI INDEX.
PAGE
Mines of Russia - 204
Spain - 203
Tennessee - - 298
Turkey - 203
United States - - - 215
ventilation of - - 182
Minnesota Mine - 247
Mosaic gold - - 356
Muntz's metal - - 355
Native Copper Mining Company - - 229
silver and mercury in - - - - 70
New York and Michigan Mine - 228
Nicking buddle - 190
Nitrate of copper - - 59
Nitride of copper - - 40
North American Mining Company - - 242
North Carolina Copper Mining Company - - 272
North- West Mining Company of Detroit - 236
Michigan - - 235
Norwich Mining Company - - 252
Olivenite - 88
Ontonagon District - - 244
Ores, crushing of - - 183
dressing - ib.
jigging - - 186
stamping - 184
washing - 185
of copper - 68
analysis of - 90
classification of 68
for smelting - 289
Oxides of copper - 34
Oxychlorides of copper - 45
Pakfong ------- 359
INDEX. XV11
PAGE
Patapsco Mine - 265
Percussion table - - 190
Perkiomen Mine - - 283
Peroxide of Copper (see Binoxide)
Phillipsite - V?
Phoenix Mining Company - - 230
Phosphate of copper - - - 58
Phosphide of copper - 42
Phosphorochalcite - - 88
Pinchbeck - - S55
Pittsburg and Boston Mining Company, (see Cliff Mine.)
Isle Royale Mining Company - 244
Platin - 355
Polk County Mine - - 2V 8
Polysulphides of copper - - 42
Portage Lake Mining District - - 258
Porphyry - - 147
Prince's metal - 355
Protoxide of copper - - 36
hydrated - - 38
salts of - - - - - 49
Rack -
Red brass
copper
oxide of copper, (see suboxide.)
Refining
Resin of copper
Rocks -
classification of
Rosette copper
Royal Santiago Mining Company
191
355
n
44
144
146
346
215
Santa Rita del Cobre Mir
Scheele's green
Schists
Schuyler Mine
285
66
148
281
XV111 INDEX.
PAGE
Schweinfurth green
Selvages - - 163
Shafts - 1T5
Shoding - - 173
Silicate of suboxide of copper - 49
copper
Silicofluoride of copper - 47
Silver, detection of, in copper ores - - 91
Similor - 355
Siskawit Mine - 244
Slag - - 303
Sleeping table - 189
Slickensides - - 164
Slope - - 157
Smelting, Birkmyre's process - - 334
Brankert's process - - 333
Davies' process - - 334
De Sussex's process - 335
English process - - - 288
French process - - - - 337
Low's process - - 336
Mansfeld's process - - 340
Napier's process - - 331
Parkes' process - - 336
Rivot and Phillips' process - - 333
Trueman and Cameron's process - - 336
South Cliff Mine - - 242
Speculum metal - - - 375
Springfield Mine - 263
Stamp work - - 228
Star Mining Company - - 234
Stoping - - 177
Strings - - 157
Subacetate of copper - 49
Subchloride of copper - - 43
Subfluoride of copper - 47
Suboxide of copper - - 84
hydrated ----- 36
INDFX.
PAGE
Suboxide of copper, salts of -
- % - 48
Subsulphide of copper
40
Subsulphophosphite of copper
67
Sulphate of copper
51
and potassa
58
basic -
57
Sulphite of suboxide of copper
48
Sulphide of copper - -
41
Surface indications -
- 170
Swansea, mode of smelting copper at -
- 288
sales of ore at
- " - 386
Tam-ta.m metal
- 374
Tennantite - -
83
Tenorite - ...
72
Terfluoride of copper -
47
Threads
- 157
Thrombolite - -
88
Timbering -
181
Tinning copper
- 376
Toltec Consolidated Mine
- 247
Tombac -
- 355
Trachytes -----
- 147
- ib
Tutenag -
- 360
Tyrolite -
89
Underlie
- 157
Variegated copper
77
Veins, Weissenbach's classification of-
- 156
gash -----
- 159
opening of
- 172
segregated -
- 158
true - -
- 160
Wall -
- 157
Warren Mine -----
- 257
XX INDEX.
PAGE
Washington Mining Company -
Waterbury Mining Company -
Wheal Jamaica
Whim- - ltJG
White metal - - 310
Wild Cat Mine - 269
Winzes - 177
Wolfsbergite - - 83
Yellow metal ------- 354
CHAPTER I.
CHEMICAL RELATIONS OP COPPER.
COPPER being an abundant metal, easily reduced from
some of its ores, and susceptible of a great variety of
important applications, might be supposed to be dis-
covered at an early period of the world's history.
Accordingly we find it among the few metals mentioned
in the Pentateuch. Moses tells us that the antedilu-
vian metallurgist, Tubal Cain, was the father, that is, the
instructor or master of all those that work in brass and
iron. The Egyptians used it largely, and with them, as
with other ancient nations, it supplied the place of steel.
Hesiod tells us that iron was a late invention, brass
being the material out of which the weapons of antiquity
were fabricated. The shields, helmets and swords of
Homer's heroes were also formed of it. In later times,
when iron had superseded the ancient metal, the same
name, zaixtvt, originally applied to the armorer, and
meaning a worker in brass or bronze, was retained as
the appellation of the blacksmith who wrought in iron.
The brass of the ancients or 2<axo$, a word derived from
the Arabic, and signifying any thing capable of being
polished, was not the compound to which we apply that
name, but a sort of bronze or alloy of copper and tin.
Our English word copper, together with the terms
3
26 CHEMICAL RELATIONS OF COPPER.
used in most of the modern languages to designate this
metal, is derived from the Latin cuprum, which itself
comes from Cyprus, or Kupros, as it was spelt by the
Greeks, an island sacred to Venus, where it was exten-
sively mined and smelted in very ancient times. The
alchemical title of copper was Venus, and the symbol
of the planet was, in that singular old astro-chemical
system, applied to the metal.
Gopper. Copper is distinguished from all metals,
except titanium, by its color, which is a fine brownish
red, slightly inclining to yellow. When reduced to a
very thin pellicle, it is transparent, and by transmitted
light, has a beautiful green color. Films of this kind
may be obtained by heating a little oxide or chloride of
copper in a glass tube through which a current of
hydrogen gas is passed, when the glass is coated by a
layer of metal of extreme tenuity, displaying a red
color by reflected, and a green by transmitted light.
When warmed or rubbed it gives off a disagreeable
smell and a peculiar faint nauseous metallic taste. It
is susceptible of a high but fugacious polish, as it is
extremely liable to tarnish.
Native copper is occasionally found crystallized in
regular octahedra. These may also be obtained arti-
ficially by allowing fused copper to cool very gradually
in a crucible, then breaking the outer crust and pouring
out the still liquid metal, when the inner surfaces will
be found to be lined with small crystals of this form.
The galvanic process of precipitating copper yields the
same result. When thrown down from its solutions by
other metals, its crystals have usually a cubical form,
and are very small.
CHEMICAL RELATIONS OP COPPER. 27
Copper is both malleable and ductile. Gold and }
silver only exceed it in malleability, while in ductility
it is surpassed by gold, silver, platinum and iron. It
can be beaten into very thin leaves, while it cannot be
drawn out to extremely fine wire. In a state of minute
division, it welds like gold, a property which has been
taken advantage of in the manufacture of medals. Fine
copper powder is strongly forced into the die, and an
unusually sharp and clear impression is thus obtained.
The medal may be afterwards hardened by careful
annealing.
It is more tenacious than any of the other metals
excepting iron. A copper wire, one-tenth of an inch
in diameter, is capable of supporting a Aveight of 385 y ;
pounds. It is soft enough to be cut with a knife, but is
more resisting than lead. It is the most sonorous of
the metals, and constitutes an important part of those
alloys which are used in the manufacture of bells,
gongs, &c.
The specific gravity of copper fused in the open air \
is lower than that of the metal under other circum-
stances, because some oxygen is absorbed from the air.
It reaches only 8.7 or 8.8. Fused under a protecting
slag, its specific gravity is 8.91 to 8.921. That of the
unignited wire is 8.939 to 8.949; of the ignited wire,
8.93 ; of flattened wire and well rolled sheet, 8.95 to
8.96.
Copper melts at a full red heat. The fusion point has
been stated to be 1996 F. ; intermediate between those
of silver and gold. At a white heat it burns with a bril-
liant green flame. At high temperatures below its
28 CHEMICAL RELATIONS OE COPPER.
point of combustion it is volatile, and even at its fusing
point a small quantity escapes into the atmosphere. In
the most carefully managed furnaces, this loss is unavoid-
able, and has been said to amount to the fourth of one
per cent., though bad management will raise it very
much above this. It is, however, difficult, if not impos-
sible, to determine with any accuracy the amount of loss
from this source, because it cannot be ascertained with
precision how much soaks into furnace bottoms and how
much is lost in other furnaces in the reduction of
refinery slag. All the ores of copper are more or less
volatile, and in a furnace without a culvert much metal
must necessarily be lost. The author has known 20
tons of fine, impalpable, reddish brown powder, con-
taining on an average 14 per cent, of copper, to be
taken out of the culvert of a smelting establishment, as
the residuum of about 3000 tons of ore, averaging 22
per cent. This, however, must not be taken by any
means as the standard of volatility for ores of copper,
because much of this was, in all probability, swept up
the chimney mechanically by the strong draught of air.
Commercial copper varies remarkably in purity.
Russian copper is generally very nearly chemically
pure. Some of the American copper is also very free
from impurities. Most of the refined metal, however,
in all countries, contains lead, iron and antimony, and
the best of it is scarcely ever free from traces of carbon
and suboxide of copper. The pig copper of commerce
is of course always impure. That from South America
is often extremely bad, being not only carelessly
smelted and therefore containing the ingredients of the
CHEMICAL RELATIONS OF COPPER. 29
ore, but fraudulently mixed -with fragments of old iron
to increase the weight. Pigs of this metal, -which are
nothing but bars of iron encased in copper, are occa-
sionally imported into this country from the smelting
houses on the west coast of South America.
For many laboratory uses, good commercial copper is
sufficiently pure. The turnings are often used, and
then it is necessary that they should undergo some
little preparation. The grease with which they are
commonly contaminated is burned off by heating them
to redness in the open air. This cannot, however, be
done without coating them with black oxide, which is to
be removed by heating them in a current of dry hydro-
gen gas, until no more steam is given off, and the sur-
face is perfectly pure and free from tarnish of any kind.
The metal is then allowed to cool in an atmosphere of
hydrogen. *
Strips of sheet copper are often used in some ana-
lytical processes, such as, for example, Levol's method
of ascertaining the quantity of copper in an ammoniacal
solution of the black oxide, or Eeinsch's test for arsenic.
For the former purpose, common sheet copper will
answer, provided its surface has been carefully cleansed.
For the latter, the author has been in the habit of using
the faces of Swiss watches. The enamel is carefully
beaten off, and the copper passed through a gold-
beater's mill. The surface being then cleansed with
dilute acid is extremely sensitive to the smallest traces
of the poison in question. Copper gauze is often used
for the same purpose.
Perfectly pure copper is obtained by precipitating the -
3*
30 CHEMICAL RELATIONS OF COPPER.
metal from a solution of chemically pure sulphate of
copper, on a surface of copper, by the galvanic pro-
cess. It is also procured by passing a stream of hydro-
gen through a heated tube containing absolutely pure
oxide of copper. It is then in the form of a red powder
which, however, readily assumes the metallic lustre on
being rubbed between two hard polished surfaces.
At ordinary temperatures, copper does not tarnish
when exposed to perfectly dry air or oxygen gas. In
moist air, especially if acid vapors be present, it be-
comes rapidly coated with a layer of oxide, which
absorbs carbonic acid from the atmosphere and is con-
verted into a green basic carbonate, mingled with oxide,
commonly known as verdigris. Every imaginable tint
of olive green is produced by the variable mixtures of
these two ingredients. A surface of metallic copper,
moistened with acid and exposed to the atmosphere,
combines with the oxygen of the air, and the resulting
oxide unites with the acid, producing a neutral salt,
which, by the action of its oxygen upon the metal, is
ultimately reduced to basic salt adhering firmly to the
metal.
In a solution of ammonia, copper is also oxidated, a
blue solution resulting. Dilute solutions of chloride
of sodium (common salt) dissolve copper very rapidly,
while concentrated solutions of the same salt exert little
or no effect on it. It has been suggested that this
action is a galvanic one, circles being formed between
the copper and the small particles of foreign metals and
other impurities existing in it, though it is not easy to
see how the dilution renders the solution more active.
CHEMICAL RELATIONS OF COPPER. 31
At a white heat copper feebly decomposes steam,
converting it into oxygen and hydrogen. At common
temperatures this change does not take place. Acids
even do not enable it to effect the decomposition of
water at the ordinary temperature. In a state of fine
division, copper is dissolved by hydrochloric acid, while
in larger masses this reagent scarcely affects it. Its
action is probably dependent upon the oxygen of the
atmosphere. Strong sulphuric acid, especially when
aided by heat, dissolves it, with the evolution of sul-
phurous acid gas, a phenomenon which shows that the
oxidation of the metal takes place at the expense of the
acid itself, and not of the water with which it is com-
bined. Cold nitric acid, of any degree of concentra-
tion, dissolves it rapidly, with the evolution of copious
red fumes of hyponitric acid, resulting from the action
of atmospheric air upon the deutoxide of nitrogen.
Fatty matters also predispose copper strongly to
unite with oxygen. Hence vessels of copper can only
be used with safety for a very few culinary purposes, as
its compounds are decidedly poisonous.
The symbol of copper is Cu. Its equivalent, as de-
termined by the reduction of the black oxide by hydro-
gen, is 31.71 on the hydrogen, and 396.7 on the oxygen
scale.
USES OF COPPER. Copper is used for a great variety
of purposes in the arts. One of the most extensive of
its applications is that of sheathing, and bolts for ships.
It is of service here, because it is less readily acted upon
by sea-water than any other of the cheap metals, and
because the friction of the water upon it is less than it
32 CHEMICAL RELATIONS OP COPPER.
would be upon wood. Iron cannot be substituted for it
even in a ship's bolts, because the sea air is sufficiently
impregnated with salt to corrode this metal with great
rapidity.
It is used also to alloy the precious metals. These are
too soft to be worked to any advantage without the
introduction of copper, which gives the necessary hard-
ness, without diminishing the lustre, and if proper pre-
cautions be taken, without impairing the color of the
alloys. It is consequently the common alloy in jewelry
and in gold and silver coinage. Its combinations with
the cheaper metals, which are very important, will be
described in another place.
It is also peculiarly adapted to boilers in which saline
waters are to be used, as the incrustations are not so
adherent as they are to iron boilers, neither are they so
corrosive in their action. They are easily removed, and
leave the surface of the boiler perfectly clean and bright,
so that the thickness of the boiler not being diminished,
there is none of that danger of explosion which attends
the use of iron boilers under similar circumstances.
As copper was one of the earliest, so it continues to
be the best material on which to execute artistic engra-
vings. Steel has been lately substituted, from motives
of economy, as it is capable of yielding a larger number
of impressions, but it is not susceptible of that mellow-
ness and richness of effect to be obtained from copper.
Etchings are made upon the surface by covering it with
a varnish, and then engraving through this with a sharp
tool. The shadows are produced by cutting into the
plate with gravers and deepening the impressions with
CHEMICAL RELATIONS OF COPPER. 33
acid, while varnish is spread over the lights and middle
tints to protect them from the corrosive action. The
rationale of this is that, when these plates are put upon
the press, the darkest portions of the impression corres-
pond with the broadest and deepest furrows upon the
surface of the copper.
NON-SALINE COMPOUNDS OP COPPER.
Oxides of Copper. When copper is heated in the
air, it is covered with a red film of suboxide which
passes gradually into the black or protoxide. When
copper is fused in the atmosphere, tarnishes, of various
hues of yellow, red, purple and black, form on the surface.
These indicate various admixtures of the two oxides with
metal, and may be conveniently seen on the surface of
ingots sent to market. When these have been allowed
to cool too long in the air after being cast, they are
invariably coated with a black layer. When they have
been early immersed in the water, the tarnish is either
an orange yellow, a fine ruby red, or a mixture of the
two. It is upon the proper management of this that
the preparation of Japan copper depends. This is cast
in small moulds, and the moment it becomes consoli-
dated, it is thrown into water where it becomes covered
with the well known beautiful red film of suboxide.
Heated in oxygen or the flame of the compound blow-
pipe, copper burns with a rich green flame, and is wholly
converted into black oxide. Its tarnish, gradually ac-
quired from the atmosphere, is at first, a warm, deep
brown, which gradually passes into the dark olive-green,
34 CHEMICAL RELATIONS OF COPPER.
so highly prized by antiquaries, a color produced by the
mixture of the carbonate with the two oxides.
Copper forms four definite compounds with oxygen.
1. The suboxide, or red oxide, Cu 2 0.
2. The protoxide or black oxide, CuO.
3. The binoxide, Cu0 2 .
4. Cupric acid the composition of which is undeter-
mined.
Suboxide of Copper* Cu 2 0, 71.42. The native
dioxide will be described in the next chapter. It is
often found as a product of furnace operations. Much
of the slag from a refining furnace is composed of this
oxide. It then is of a deep red color, oftener porous
than compact, and mingled with various impurities.
It may be obtained by several processes.
1. Ignite in a well covered crucible a mixture of
31.71 parts of metallic copper with 39.71 parts of black
oxide. This mixture aggregates at a high temperature
and a red fused mass of the suboxide is obtained. An
analogous process of reducing the black oxide is to heat
to redness in a carefully closed crucible, alternate layers
of fine copper sheet and black oxide.
2. Heat in a crucible a mixture of subchloride of
copper with carbonate of soda, and then dissolve out
the chloride of sodium and the excess of carbonate of
soda by water. The suboxide is left as a deep red crys-
talline powder. A very fine metallic pigment has been
* It is proper to state here that this suboxide is called by some the
protoxide, while the black oxide is rated as a peroxide. The form also
adopted in the text, however, is that which is now universally adopted
by chemists.
CHEMICAL RELATIONS OF COPPER. 35
made by a process resembling this. Sulphate of copper
is mixed -with carbonate of soda, in the proportion of
100 parts of the former to 59 of the latter. These
mixed salts are fused in their water of crystallization at
a low temperature, and the heat is continued till the
mixture is dry, when 25 parts of finely divided metallic
copper are mixed with and the whole is heated to white-
ness, in a covered crucible, for twenty minutes.
3. A solution of some salt of the black oxide is
mixed with a solution of grape sugar, (cane sugar may
be converted into this variety by boiling it with a few
drops of dilute sulphuric acid.) Potassa is then added
till the precipitate first formed is completely re-dissolved,
forming a violet-blue fluid. This is boiled for some
time, when the suboxide is deposited in small bright red
crystals.
This oxide is always formed when a large quantity of
metallic copper is fused under scoriae sufficiently thin to
admit a little atmospheric air. It is often found on the
sides of refining furnaces mixed with the black oxide,
and then the mass is crystalline in its texture, dark
gray in color, with metallic lustre, and flecked with splen-
did ruby-red, semi-transparent particles.
This compound varies in color from a brownish cop-
per-red to a pure carmine tint. In a dry atmosphere it
may be kept a long time, but moisture rapidly peroxi-
dates it. Heated to redness, it is converted into the
black oxide. The acids act upon it variously. Most of
them decompose it into a salt of the black oxide and
metallic copper. Strong nitric acid oxidates it with
the evolution of binoxide of nitrogen. Hydrochloric
36 CHEMICAL RELATIONS OF COPPEK.
acid dissolves it, forming a colorless solution, from which
the alkalies and their carbonates throw down yellow
and red precipitates, and ferrocyanide and iodide of po-
tassium white or brownish ones. Ammonia, dissolves it
to a colorless fluid, which rapidly becomes blue when ex-
posed to the air, in consequence of absorption of oxygen.
This blue solution is decolorized again by being allowed
to remain in a well-closed bottle in contact with strips
of metallic copper.
Fused with glass, this oxide forms a fine rich ruby-
red, when proper care is taken to prevent oxidation. A
little metallic tin is often mixed with it for this purpose.
Its coloring power is very intense, so that an exceed-
ingly thin film may be blown out as a covering to a
vessel of transparent glass. The outer film may be
then cut through, and various forms obtained in color-
less glass. Pastes are also colored by it to imitate the
ruby and the garnet.
Hydrated suboxide of copper, 4Cu 2 0,HO. This is
prepared by decomposing the subchloride with potassa
or soda. It is a yellow powder, which rapidly absorbs
oxygen from the air, and must, therefore, be dried in
vacuo.
The suboxide is a feeble base, forming salts, which
will be presently described.
Oxide or Protoxide of Copper, Black Oxide. CuO.
39.71. This oxide is found native, and is always
formed when copper is heated in the air, or precipi-
tated from its solutions by alkalies. The author has,
in his collection, specimens of this oxide in acicular
crystals, lining the cavities of fire-brick from the sides
CHEMICAL RELATIONS OF COPPER. 37
of a refining furnace, through which it had passed either
by filtration or sublimation, probably the latter.
It is prepared by roasting copper filings, or calcining
the finely divided copper obtained from the ignition of
the acetate, but better by igniting the nitrate. Several
methods of performing this ignition have been suggest-
ed. The most common is to heat the nitrate to white-
ness in a Hessian crucible. An improvement on this
process has been made by heating the salt in a vessel
made by striking up an entire piece of sheet-copper.
This vessel is, indeed, corroded by the process, but it
furnishes additional portions of oxide. Another method
is to mix the nitrate with half its weight of copper
filings, to expose the mixture to the air, and to ignite
the basic nitrate thus obtained. The object of the last
named modifications is to increase the yield, and so to
economize the acid. Another method is to ignite the
hydrated oxide obtained by precipitating copper salts
with potassa.
Oxide of copper, as ordinarily seen, is a powder ran-
.ging in tint from a deep brown to a blueish black.
When strongly heated, it fuses, and, at a very high
temperature, loses some of its oxygen, being converted
into mixture of the black and red oxides. The fused
oxide is a deep, lustrous, iron-gray mass. Fused with
hydrate of potash or soda, it forms a blue or green
mass, easily decomposed by water. When this fused
mass is allowed to cool slowly, the oxide crystallizes in
tetrahedra, which are easily obtained by dissolving out
the alkalies with water.
Deoxidating agents, such as protoxide of iron, proto-
4
38 CHEMICAL RELATIONS OF COPPER.
chloride of tin, and organic matters at a boiling tempe-
rature, convert it into dioxide. Hydrogen and carbon,
aided by heat, easily reduce it to metallic copper. The
former of these agents effects the deoxidation at a heat
below redness.
This oxide is insoluble in water, but dissolves in acids,
forming important salts. All the valuable salts of cop-
per have this oxide for their base.
The oxide of copper is extensively employed in or-
ganic analysis as a source of oxygen ; the substance to
be analyzed is mixed with the perfectly dry and warm
oxide, introduced into combustion-tube, and gradually
heated to redness. The hydrogen and carbon are con-
verted into water and carbonic acid, which are collected
in a proper apparatus.
This oxide is used to color glass, green or blue. It is
employed in the manufacture of artificial gems to imi-
tate the emerald, for which purpose it is usually mixed
with chrome or sesquioxide of iron.
Hydrated Oxide of Copper. CuO,2HO. This is
obtained as a pale blue precipitate by adding excess of
a solution of potassa to a solution of any copper salt.
Should too little alkali be used, a basic salt will be
formed. The water is very feebly united with this oxide,
for should the blue precipitate be boiled with its super-
natant solution, it is converted into the heavy, anhy-
drous black oxide. The same change takes place, but
more slowly, when this hydrated oxide is exposed to the
air. In order, therefore, to procure the hydrated oxide
of the formula given above, it must be dried under the
exhausted receiver of nn air-pump.
CHEMICAL HELATIOKS OF COPPER. 39
The pigment known as blue verditer, has this ox-
ide for its basis. It dissolves readily in acids, and in
water of ammonia. With the latter liquid it forms a
fine purplish blue solution, called celestial water. Two
definite compounds with ammonia with oxide of copper
and water have been obtained. Their formulae are
CuO,NH 3 ,4HO, and 3CuO,2NH 3 ,6HO.
The hydrated oxide dissolves to a slight extent in cold
concentrated solutions of potassa and soda, forming blue
liquids, which deposit the black oxide when heated.
It is by the reactions of this oxide that copper is usu-
ally detected and estimated. For a description of these
reactions, the reader is referred to Chapter III.
Binoxide or Peroxide of Copper, Cu0 2 . When
the hydrated protoxide of copper is treated with perox-
ide of hydrogen, the blue substance assumes a brownish
yellow color, and, by the abstraction of another atom of
oxygen from the fluid, is converted into a deutoxide.
A very slight elevation of temperature decomposes it
into protoxide and oxygen : acids have the same effect.
Under water it undergoes spontaneous decomposition,
and can only be dried over sulphuric acid in vacua.
It is of no special interest.
Cuprio Acid. When finely divided copper is fused
Avith hydrate of potassa and nitre, or when hydrate of
copper is dissolved in hypochlorite of potassa, a salt is
obtained in which a combination of copper with oxygen
seems to play the part of an acid. The solution is blue,
and is very easily decomposed. Heat precipitates
from it black oxide of copper, oxygen being at the same
time evolved. By reason of this instability, this acid
40 CHEMICAL RELATIONS OF COPPER.
has never been exhibited in a separate state, and there-
fore no atomic constitution can be assigned to it.
Copper and Hydrogen. Cu 2 H. Wurtz has obtained
a compound of copper and hydrogen, by heating, at a
temperature of 158, a solution of sulphate of copper
with hypophosphorus acid.
Thus prepared, the hydride of copper is a bright
brown po\vder, which oxidizes in the air. At about
140 F. it decomposes, being resolved into metallic cop-
per and hydrogen gas. Hydrochloric acid decomposes
it, forming protochloride of copper which dissolves,
while hydrogen gas is liberated.
Copper and Nitrogen. By passing a current of dry
ammoniacal gas over oxide of copper (CuO) heated
to 599, a nitride of copper has been obtained by Schrb'tte,
who assigns to it the formula Cu c N. It is, however,
mixed with excess of oxide of copper, which is dissolved
out by ammonia.
It is a deep green amorphous powder, which is de-
composed with some violence at a heat below redness.
It dissolves in hydrochloric acid, yielding chloride of
copper and sal-ammoniac.
COPPER AND SULPHUR.
There are a number of combinations of copper and
sulphur ; but those best understood are the subsulphide,
corresponding with the dioxide and the sulphide, an-
swering to the protoxide.
Subsulphide of Copper. Cu 2 S. In the vapor of
sulphur copper burns brilliantly, and this sulphide is
the result of the combustion. It is sometimes found in
CHEMICAL RELATIONS OF COPPEll. 41
copper furnaces, crystallized in regular octahedra. In
the laboratory, it is prepared by mixing three parts of sul-
phur and eight of copper turnings, heating them till com-
bination takes place with evolution of heat and light,
grinding the substance thus obtained to powder, and
heating again with a little sulphur, in order to mine-
ralize the remaining metal.
This sulphide is much more fusible than metallic cop-
and is not decomposed by heat. When roasted in the
air, it is converted partly into sulphate and partly into
oxide of copper. It cannot be reduced by hydrogen,
and when heated with carbon, it is only partially re-
duced to metallic copper. Fused with caustic alkalies
and cyanide of potassium, metallic copper is separated.
When a mixture of the sulphate and subsulyhide of copper
is heated together, decomposition takes place, metallic
copper and sulphurous acids being the results. Hydro-
chloric acid does not attack it, but aqua regia dissolves it.
Sulphide of Copper. CuS. When hydrosulphuric
acid or a soluble sulphide is introduced into a solution
of a copper-salt, a black precipitate of sulphide of copper
falls. This must be washed with sulphureted hydrogen
water, and dried rapidly over sulphuric acid in vacuo.
It is a black powder, which, when exposed to the air,
especially if damp, becomes dusky green from absorp-
tion of oxygen and conversion into sulphate of copper.
Heated out of contact with atmospheric air, it loses one
half its sulphur, and is converted into the subsulphide.
Roasted in the air, it gives off sulphur and sulphurous
acids, and is changed into a mixture of the oxide and
sulphate of copper.
42 CHEMICAL RELATIONS OP COPPER.
Boiling sulphuric acid does not attack it ; hydrochlo-
ric acid has hardly any action upon it, but nitric acid
dissolves it, separating the sulphur and forming nitrate
of copper which remains in solution. It is slightly solu-
ble in yellow sulphide of ammonium,* but not in sulphide
of potassium.
HIGHER SULPHIDES OF COPPER are said to have been
obtained by the action of the polysulphides of the alka-
line metals upon copper salts.f
An oxy sulphide, of the formula 5CuS,CuO,HO, is
said, by Pelouze, to be precipitated when a boiling
solution of nitrate of copper, mixed with excess of
ammonia, is treated with a soluble sulphide.
COPPER AND PHOSPHORUS.
When finely divided copper is heated in the vapor of
phosphorus, there is obtained a gray, brittle metallic
mass, containing about 20 per cent, of phosphorus.
A phosphide of the formula Cu 2 P is formed by pass-
ing a current of hydrogen over heated phosphate of
copper. Another phosphide, Cu 3 P, falls as a black
precipitate when phosphureted hydrogen is passed
through a copper solution of a copper-salt. There are
other phosphides, but they have not been studied.
* When sulphide of ammonium is first prepared, it is colorless, but
after a time it becomes yellow, in consequence of the separation of sul-
phur which dissolves in the liquid. Its properties are now somewhat
changed ; hence the particularizing of this form of the sulphide.
{ The alkaline metals are sodium and potassium, and the term
" polysulphides" is used to denote those sulphurets of these metals
which contain several atoms of sulphur to one of metal.
CHEMICAL RELATIONS OF COPPER. 43
SALTS OF COPPER. HALOID SALTS.*
Sulchloride of Copper. Cu 2 Cl. There are several
methods of preparing this compound.
1. A solution of chloride of copper is boiled over me-
tallic copper until its green color changes to brown.
The clear liquid is then decanted and mixed with a
large quantity of water, which precipitates the subchlo-
ride. This precipitate must be rapidly washed with
boiled water, and kept under a layer of water in a
well-closed bottle. When a strip of copper is used,
instead of copper turnings the subchloride is deposited
in white tetrahedral crystals upon the surface of the
metal.
2. A solution of chloride of copper is precipitated
with a concentrated solution of protochloride of tin,
* The old definition of a salt was a combination of an acid with a
base. Subsequent investigation, however, proved that, in the direct
formation of many salts, there was a decomposition of both base and
oxide. Thus, when hydrochloric acid is poured upon soda, this dou-
ble decomposition is effected by the oxygen leaving the soda and the
hydrogen abandoning the acid. These two elements thus combine
to form water, while the chlorine and the sodium unite to form a
chloride of sodium, and not, as it was formerly called, a mur-
iate of soda. As there is a large number of these salts, which
correspond with chloride of sodium or common salt in their
constitution, the name Haloid salts, (from the Greek word dx,
signifying common salt,) has been applied to the entire class. Their
characteristic is that they are formed by a direct union of two simple
bodies, or of compound radicals with one another, or with a simple
body commonly a metal.
The oxysalts are still regarded by most chemists as constituted ac-
cording to the old formula, though some have classified them under
the same head with the haloids, altering the acid formula.
44 CHEMICAL RELATIONS OF COPPER.
containing a little free acid. The subchloride goes
down. The reactions are shown by the formula,
2CuCl+SnCl==Cu 2 Cl+SnCl 2 .
This chloride may be obtained in small tetrahedral
crystals by dissolving the amorphous compound in hot
hydrochloric acid, which deposits the crystals as it cools.
3. When the protochloride is heated, it parts with
half its chlorine, and is converted into anhydrous sub-
chloride.
4. When chloride of mercury is distilled with copper
filings, the mercury passes over, and this chloride is left
behind. Boyle, who procured it in this way, called it
resin of copper, from its resemblance to common resin.
This chloride varies in its tint according to its mode
of preparation. As usually obtained, it is white, but
may also be yellow or dark brown. It is fusible at a
heat just below redness, (752 F.) and volatile at a
higher temperature. It soon changes in the air, in con-
sequence of the absorption of oxygen, and becomes
converted into a green mixture of hydrated oxide and
chloride. It is nearly insoluble in water, but dissolves
in hydrochloric acid, forming a brown liquid, from
which, as already stated, water precipitates the sub-
chloride. It is also very soluble in ammonia, forming
with it a colorless solution. This property renders it
a valuable agent in eudiometric analyses, for separating
oxygen from mixed gases. A solution of common salt
also dissolves it. Alkalies decompose it, precipitating
from it the suboxide.
Chloride or Protochloride of Copper. CuCl. When
finely divided copper is heated in an atmosphere of
CHEMICAL RELATIONS OP COPPER. 45
chlorine gas, it takes fire, and forms the anhydrous
chloride of copper. This is a yellowish brown sub-
stance, which is decomposed by heat into chloride and
the subchloride.
The hydrated chloride is prepared by dissolving the
oxide in hydrochloric acid, or the metal in aqua regia,
evaporating and allowing the solution to crystallize.
It forms beautiful green needles, which are very deli-
quescent and easily soluble, both in water and alcohol.
When the latter solution is kindled, it burns with a
beautiful green flame. The solution is blue when
diluted, but a rich emerald green when concentrated, or
when mixed with excess of hydrochloric acid. The
anhydrous chloride absorbs three equivalents of ammo-
nia, and is converted into a blue compound.
Oxchlorides of Copper. There are three combina-
tions of the chloride and oxide of copper, containing one
equivalent of the former to two, three or four equivalents
of the latter.
Brunswick Green. CuCl,3CuO,4HO, is the most
interesting of these compounds. This well-known pig-
ment is made by digesting hydrated oxide of copper in
a solution of the chloride, or more commonly by exposing
plates of copper moistened with hydrochloric acid or sal-
ammoniac to the action of the atmosphere. It is a green
powder, soluble in acids but not in water. On the appli-
cation of heat it loses water and becomes brownish black.
When chloride of copper is precipitated by a small
quantity of potassa, a pale-green powder is thrown
down having the composition CuCl,2CuO,4HO. Heated
strongly it becomes black, all the water being driven off,
46 CHEMICAL RELATIONS OF COPPER.
leaving CuCl,2CuO. Kept at 208, a brown com-
pound is left, CuCl,2CuO,HO. The black substance
moistened becomes CuCl,2CuO,3HO.
Double Chlorides The double chloride of copper and
ammonium, CuCl,NH 4 Cl,2HO, is obtained by mixing
saturated solutions of chloride of ammonium and chloride
of copper, or by precipitating with ammonia a solution
of chloride of copper containing excess of hydrochloric
acid. It crystallizes in beautiful blue rhombs, soluble
in water, efflorescent in the air, changing into a greenish-
white powder.
When hot chloride of copper is saturated with ammo-
niacal gas, ammonia-chloride, CuCl.NH 3 , is formed,
which is decomposable by water. This dissolves a biam-
monia-chloride, CuCl,2NH 3 , which crystallizes in dark-
blue prisms, having the formula CuCl,2NH 3 ,HO. A
tri-ammonia-chloride, CuCcl,3NH 3 , also exists.
A double chloride of copper and potassium is formed by
mixing strong, hot solutions of the two chlorides. While
cooling, the solution deposits blue octahedra, belonging
to the quadratic system, and having the formula KC1,
CuCl,2HO. The subchloride, used instead of the chlo-
ride, furnishes a double salt, crystallizing in anhydrous
octahedra of the regular system.
Bromide of Copper. CuBr. Oxide of copper dis-
solved in hydrobromic acid and evaporated, forms green
crystals of the form CuBr,5HO, which by heat separate
into bromide and subbromide, Cu 2 Br. Dry bromide
absorbs ammonia, leaving CuBr,5NH 3 . There are several
other ammonia-bromides and a basic salt, but none of
any particular interest.
CHEMICAL RELATIONS OF COPPER. 47
Diniodide of Copper. Cu 2 L When a solution of
iodide of potassium is added to another of blue vitriol,
one half the iodine separates, sulphate of potassa remains
in solution, and a brownish-white subiodide of copper,
mixed with finely divided iodine, is precipitated. The
latter is washed off with alcohol. The sub-iodide is
fusible and easily decomposed by nitric and sulphuric
acids and by alkalies. The iodide has not been sepa-
rated. A blue ammonia-iodide, however, exists of the
formula CuI,2NH 3 ,HO.
Sulfluoride of Copper. Cu 2 ,Fl 3 . Hydrofluoric acid
brought in contact with hydrated suboxide of copper
converts it into a fusible suLJuoride. The silico-sub-
fluoride 3Cu 2 F1.2SiFl, resembles it in color and char-
acter.
Terfluoride of Copper. CuFl 3 . Hydrofluoric acid
forms with black oxide of copper a blue solution, from
which this fluoride separates in crystals containing two
equivalents of water. It forms with the alkalies and
alumina, green soluble double salts. An oxyfluoride
(CuFl,CuO,HO) is formed by treating the blue fluoride
with hot water.
A borcfluoride is obtained by decomposing sulphate
of copper with borofluoride of barium. It separates in
blue deliquescent crystalline needles of the form CuF,
BF1 3 .
The silico-fluoride is in blue prisms containing twenty-
one equivalents of water, two of which are separated by
the efflorescence of the salt.
48 CHEMICAL RELATIONS OF COPPER.
AMPHID SALTS.* OXYSALTS.
SALTS OF THE SUBOXIDE. Salts of the suboxide are
obtained by dissolving the suboxide in dilute acids.
Sulphite of the Suboxide of Copper Sulphite of Cop-
per. Cu 2 0,S0 2 . When sulphurous acid is poured upon
hydrated oxide or carbonate of copper, a double de-
composition ensues, which may be understood by the
formula 3CuO+2S0 2 =CuO,S0 3 +Cu 2 0,S0 2 . Sulphate
of copper is formed at the expense of one part of the
oxide and is dissolved, and the remaining suboxide
unites with the residual sulphurous acid, forming the
subsulphite under consideration. It is also obtained by
heating a mixture of sulphate of copper with sulphite of
soda.
It is a brilliant red crystalline powder, unchange-
able when dry, soluble in hydrochloric and sulphurous
acids and ammonia, but insoluble in water. Boiling
decomposes it, and sulphuric acid exerts the same action
upon it.
* This term is derived from a.u^t, " both," and used to denote those
salts in which both base and acid are double, and contain the same
element. Thus sulphate of copper is written CuO.S0 3 , and is regarded
as a compound of oxide of copper and sulphuric acid, of both of which
oxygen is an essential constituent. Such salts are called oxysalts, but
oxygen is not the only simple body which plays this part. In sul-
pharseniate of potash, for example, sulphuret of potassium is the base,
and sulpharsenic acid the acid of the salt, which has the formula
2Ks,AsS 3 . The latter is a sulphacid, the former a sulpho-base, and the
compound a sulpho-salt. Selenium and tellurium act in the same man-
ner. To include these salts and others analogous to them which
may be discovered, it was necessary to find some generic term. To
meet this Berzelius suggested the above name, which at present seems
perfectly satisfactory.
CHEMICAL RELATIONS OF COPPER. 49
There is an insoluble double sulphite of copper and
potassa.
Hyposulphite of Suboxide of Copper, obtained by
treating the sulphate with hyposulphite of lime, is a
colorless solution. It forms several double salts with
potassa and soda.,_
Silicate of Suboxide of Copper. This is the sub-
stance which forms the coloring matter of red glass. It
is sometimes found in the quartz which surrounds native
copper.
A subacetate of copper is found as a white sublimate
lining the upper part of the retort, after the distilla-
tion of acetate of copper.
Reactions of Salts of the Suboxides. The soluble
subsalts have colorless solutions from which the fixed
alkalies throw clown the base as a reddish-yellow pre-
cipitate. Ammonia produces the same precipitate, but
rapidly dissolves it, forming a colorless solution, which
soon becomes blue in the air, from absorption of oxy-
gen and consequent change of the suboxide into oxide.
Sulphydric acid (sulphureted hydrogen) throws down
from these salts the black sulphide of copper.
For the study of these reactions the subchloride is the
proper salt to select.
SALTS OF THE PROTOXIDE.
Reactions of Salts of Slack Oxide. The hydrated
salts of the black oxide with colorless acids are blue
or green, the anhydrous salts are white. They are
obtained usually by dissolving the oxide or the car-
bonate in acids.
r v
50 CHEMICAL RELATIONS OF COPPER.
Caustic fixed Alkalies precipitate a voluminous, pale
blue, hydrated oxide of copper, which, as we have
already said, changes to a black, heavy anhydrous
oxide when the solution is boiled over it. It is insolu-
ble in alkaline solutions when they are dilute, but dis-
solves in them when concentrated, giving them a blue tint.
Ammonia throws down the same precipitate, but a
slight excess of this reagent redissolves it, forming a
magnificent blue solution, containing a double salt of
copper and ammonia. Caustic potassa precipitates from
this solution all its copper as hydrated oxide.
SulpTiydric acid and the sulphydrates throw down the
black sulphide of copper. This is insoluble in the alka-
line sulphides, excepting in the sulphide of ammonium,
which dissolves it to a very slight extent.
The carbonates of potash and soda throw down a
greenish-blue precipitate, which is a mixture of the
hydrated oxide and the carbonate.
Ferrocyanide of potassium throws down a fine ma-
hogany or chesnut-brown precipitate. In extremely
dilute solutions it only tinges the fluid of a purplish-
brown.
Albumen forms with copper an insoluble yellowish-
white precipitate, which has been shown by Orfila to be
inert, so that albumen may be used as an antidote in
cases of poisoning by copper.
Metallic iron or zinc throws down metallic copper as
a brown powder or in crystalline flakes. In dilute solu-
tions these reagents are only tinged with a superficial
coating of copper.
Borax, and vitreous fluxes generally, fused with cop-
CHEMICAL RELATIONS OF COPPER. 51
per salts, are green when warm, but become blue on
cooling. If a bead so colored be heated in the inner
flame, especially after a little tin has been added to it,
it is reduced, and shows the fine ruby-red of the sub-
oxide. "When heated a long time it is reduced to metal.
This reduction is easily accomplished by mixing the
substance with carbonate of soda and heating it upon
charcoal. The bead then rubbed up with water in a
porcelain or glass mortar will exhibit little red spangles
of metallic copper.
The delicacy of some of these tests is remarkable. A
clean, polished rod of iron is stained with a solution
containing only one part of copper in 150,000 of water.
Iron wire is best adapted for this test. Steel is not so
sensitive. The iron will indicate the presence of copper
in a still weaker solution if it be made part of a minia-
ture galvanic battery, by wrapping a coil of fine plati-
num wire around it. SulpJiureted hydrogen gives a
brown tint in a solution of one part of copper in
100,000 of water. Tincture of guiacum gives a blue
tint, changing to green when only one part is diffused
through 450,000 of water. Ferrocyanide of potassium
colors ten gallons of water containing only one grain of
copper.
Sulphate of Copper. This salt is a common pro-
duct of mines of sulphuret of copper. The ore is
oxydized by the joint action of air and moisture, and
the water which trickles over it washes off the newly
formed sulphate. This natural process has been imi-
tated by manufacturers who calcine the native or arti-
ficial sulphuret. The latter is obtained by heating three
52 CHEMICAL RELATIONS OF COPPER.
parts of copper with one of sulphur, till the two com-
bine. The roasting is sometimes carried on in the same
furnace with the sulphuration. The fragments of old
sheathing, which has been rendered useless by the cor-
rosion of salt water, are heated to a dull-red in a
reverberatory furnace, the doors are then closed and
sulphur thrown in from above. As soon as the com-
bination has taken place, the doors are opened to admit
air, when the roasting commences; a portion of sulphur
burns off, and the rest of the sulphurct is oxydized to
proto-sulphate of copper. After the roasting has been
completed, the remaining sulphate is lixiviated. When
the last-mentioned plan is adopted, the sulphatized
sheets are hung in boilers filled with water acidified
with sulphuric acid, till the sulphate is dissolved. The
sheets are then returned to the furnaces and the same
processes are repeated till the copper is exhausted.
The addition of sulphuric acid increases the product
by dissolving some oxide Avhich has escaped the acid of
the roasted sulphuret. The solutions arc evaporated
and crystallized.
Obtained in either of these modes, sulphate of copper
is always impure, containing more or less iron, and
sometimes traces of other metals. The quantity of iron
contained in the sulphate made from the roasted ore
varies greatly with the temperature at which it has been
calcined. At a very low heat sulphate of iron only is
formed; at a bright red this salt is decomposed, and to
a considerable extent rendered insoluble. If then the
heat be sufficiently raised, this impurity will be very
greatly diminished, though not entirely god rid of.
CHEMICAL KELATIONS OF COPPER. 53
In the arts it is not always necessary to have a blue
vitriol entirely free from iron. If it be desired, how-
ever, its purification may be accomplished by heating it
to a dull redness with access of air, when nearly all the
iron will be rendered insoluble, and a portion of the
copper too will be left behind as oxide. On lixiviating
the mass we obtain a sulphate of copper, containing
little more than a trace of iron. The residuum may be
treated with sulphuric acid and the copper obtained
from it by precipitation with scraps of metallic iron.
Another method of preparing it is to moisten copper-
filings with sulphuric acid, to expose them to the atmos-
phere, and to continue this process till the copper is
entirely converted into sulphate.
A modification of the process which yields an excel-
lent article is the following. The best commercial
copper is treated with sulphuric acid diluted with one-
half its weight of water ; sulphurous acid is disengaged,
the copper being oxidated at the expense of the oil of
vitriol, and sulphate of copper is formed. To rid this
of a little sulphate of iron, it is evaporated to dryness,
and a little nitric acid is added towards the close of the
operation. This converts the iron into sesquioxide, which
is insoluble in water. The iron remains behind as basic
sesquisulphate, when the dry mass is lixiviated ; only a
very small portion of it entering into the solution. It
is said that this is totally precipitated by boiling with
carbonate or hydrated oxide of copper.
This salt is also procured in large quantities in the
process of parting gold and silver, and in the refining of
old silver coins. In these, independently of the copper
54 CHEMICAL RELATIONS OF COPPER.
contained in the coins themselves, a large quantity is
furnished by the liquor which floats over the precipi-
tated silver, resulting from the solution of the copper
used to precipitate that metal.
Sulphate of copper is obtained perfectly pure by dis-
solving pure oxide in pure sulphuric acid.
Pure hydrated sulphate of copper is an azure blue salt,
crystallizing in elongated rhombs,* of the doubly oblique
rhombic or triclinate system. These contain 32 parts
of oxide of copper, 32 of sulphuric acid, and 36 of
water in the hundred parts, and may be expressed by
the formula Cu,S0 3 ,5HO. A small quantity of iron is
recognized by the greenish cast it gives to the crystals,
especially to their effloresced surfaces. The presence of
iron and zinc in the salt is, however, better detected by
a brief and simple analytical process. A stream of sul-
phureted hydrogen is passed through a solution of the
salt, previously acidified, until all the copper is precipi-
tated as sulphide. This is filtered off, the filtrate boiled
with the addition of a few drops of nitric acid, and after
it has cooled the iron is precipitated by excess of ammo-
nia. After separating the sesquioxide of iron by filtra-
tion, the clear liquid is tested for zinc with sulphide of
ammonium, which throws down a white sulphide of zinc.
Exposed to a dry atmosphere the salt effloresce
parting with two equivalents of water. At 212 it loses
four equivalents, but retains the fifth with more tena-
* These crystals are sometimes opaque in spots, in consequence of
some of the sulphate being deposited without its water of crystalliza-
tion. This is especially the case when they are deposited from a
strongly acid solution.
CHEMICAL RELATIONS OF COPPER. 55
city. For this reason, the last equivalent has been
reckoned by some chemists as basic water, the formula
CuO,S0 3 ,HO+4HO, has been assigned to it. At from
390 to 430 this water of constitution is expelled, leav-
ing the anhydrous salt a dirty-white pulverulent mass.
At a still higher heat it is decomposed, being resolved
into sulphurous acid and oxygen, which escape, and
black oxide of copper which remains behind. The
anhydrous salt has a strong affinity for water, com-
bining with it very energetically and resuming the blue
tint of the hydrated salt.
The crystallized sulphate is soluble in four parts of
cold and two of boiling water. The solution is blue with
an acid reaction, and an unpleasant metallic taste. It
is insoluble in alcohol. Like the other salts of copper,
it is poisonous to men and animals.
"According to Kane, crystallized sulphate of copper,
when dissolved in hydrochloric acid, causes considerable
depression of temperature, and yields a green liquid,
from which chloride of copper alone is deposited upon
evaporation, provided, not less than one equivalent of
the acid has been used for each equivalent of salt ;
in allowing the crystals to remain for some time with
the mother-liquor, which contains all the sulphuric acid,
crystals of blue vitriol are reproduced. Powdered crys-
tals of sulphate of copper eagerly absorb hydrochloric
acid gas, evolving much heat and losing water ; a green
mass is obtained, which is very deliquescent and fumes
in air." Abel $ Bloxam.
Sulphate of copper combines in various proportions
with the isomorphous sulphates of zinc, iron and copper.
56 CHEMICAL RELATIONS OF COPPEE.
With iron especially, this combination takes place with
great readiness. Mixed solutions of the two sulphates
crystallize together, and the resulting crystals contain
variable proportions of the three salts. A crystal of sul-
phate of copper grows, indeed, as readily in a solution
of sulphate of iron as in its own mother-liquor. It may
be dipped alternately into concentrated solutions of the
two salts, and it will continue to increase, the layers of
the green and blue vitriol remaining quite distinct, and
being easily distinguished by their color. Sulphate of
magnesia also forms double salts with sulphate of cop-
per. In all these cases, the double salts contain five
equivalents of water when the copper-salt is in excess,
and seven when the other sulphate predominates.
The specific gravity of this salt is 2.274, water being
the standard of unity. Its water of constitution is occa-
sionally replaced by an alkaline sulphate, a crystallizable
double salt being the result.
Uses. Sulphate of copper is largely employed in
medicine. It is used as an emetic, a tonic, an astrin-
gent, a styptic, and a feeble escharotic. In dyeing it is
employed to develop the various colors of which copper
is the basis, and as a reserve in the cold indigo vat. In
the electrotype process it is used for taking copies of
medals in metallic copper. It is the salt usually selected
by the manufacturer of blue verditer, Scheele's green, and
other pigments of copper. It is sometimes mixed with
copperas in making ink ; but this is a very bad practice,
as it does not materially improve the color of the ink,
and renders it very corrosive in its action on steel pens.
Anhydrous sulphate of copper is used to deprive alcohol
of water.
CHEMICAL RELATIONS 01' COPPEll. 57
Basic Sulphates. Three have been described, of the
formulas, 3CuO,S0 3 ,2HO; 4CuO,S0 3 ,4HO; and 5CuO,
S0 3 5HO. The second of these is the mineral brochantite.
They are prepared by precipitating the sulphate just
described with a small quantity of alkali, by digesting
fresh carbonate or hydrate of copper in a solution of blue
vitriol, or by exposing ammonia-sulphate to the air.
They are pale green, insoluble, easily decomposed by
heat into water, sulphate, and oxide of copper. Kane
says that by precipitating blue vitriol with caustic
potassa, he obtained another basic salt, the composition
of which is, 8CuO,S0 3 ,12HO.
Ammonia Sulphates of Copper. There are several
double salts of copper formed with ammonia and potassa.
The ammoniacal double salts vary much in color and
composition.
When solutions of the two sulphates of copper and
ammonia are mixed and duly concentrated, we obtain
light blue, very soluble crystals of the formula NH 4
S0 3 ,CuOS0 3 ,6HO. When carbonate of ammonia and
sulphate of copper (three parts of the foianer, and two
of the latter) are rubbed together in a mortar, carbonic acid
is evolved, the mass becomes blue and moist, and another
double salt, the ammoniated copper of the pharmacopoeia is
formed. When a strong solution of blue vitriol is treated
with water of ammonia till the insoluble sub-salt first
thrown down is all dissolved, we obtain an ultra-marine
blue solution, from which by gradual evaporation, cold,
or the addition of alcohol, blue prisms of ammonia-sul-
phate of copper separate. Their formula is CuO,S0 3 ,
2NH 3 ,HO. They are soluble in 2J parts of water,
58 CHEMICAL RELATIONS OF COPPER.
and decompose in the air. At 300 they become apple-
green, having parted with their water and one equivalent
of ammonia, and at 400 one-half of the remaining alkali
is expelled. Anhydrous sulphate of copper absorbs
53.97 per cent, of dry ammoniacal gas, forming a soluble
blue, the constitution of which is represented by the
formula 2Cu,S0 3 ,5NH 3 .
Sulphate of Copper and Potassa is a light blue salt,
formed by crystallizing the mixed solutions of the sul-
phates. It is KOS0 3 Cu,S0 3 ,6HO. It loses two
equivalents of water at 212, and deposits a green basic
double salt on cooling. The double sulphate with soda
is formed in the same manner from the blue vitriol and
bi-sulphate of soda. A salt composed of the sulphates
of copper, soda and magnesia, may be formed by mix-
ture and crystallization.
Hyposulphate of Copper. CuOS 2 3 ,4HO. When
sulphate of copper is exactly decomposed by hyposul-
phate of baryta and the solution concentrated, rhombic
prisms soluble in water are obtained, from which a small
quantity of ammonia precipitates a basic hyposulphate,
and with which an excess of the same reagent forms a
double salt which crystallizes in azure square tables,
difficult of solution, permanent in the air, and composed
of CuOS 2 5 ,2NH 3 .
Phosphate of Copper. Phosphate of soda throws
down from a solution of cupreous salt, this compound as
a greenish powder, insoluble in water, soluble in acids,
becoming brown by heat. A number of basic phosphates
have been found native.
The phosphate and hypophosphate of copper possess
no particular interest.
CHEMICAL RELATIONS OF COPPER. 59
Nitrate of Copper. When nitric acid is poured upon
metallic copper, violent action takes place, even in the
cold strong effervescence ensues, heat is evolved,
copious, dense, red fumes rise, and a blue solution is
obtained. The reaction will be understood by a glance
at the formula. Thus, 3Cu+4N0 5 =3CuON0 5 +N0 2 .
The deutoxide of nitrogen, as it rises through the atmos-
phere, absorbs oxygen, and forms the red fumes of nitrous
acid. To obtain the solution, the use of concentrated
nitric acid must be avoided, or a green insoluble basic
salt will subside.
The crystals, obtained from this solution at low temper-
atures, contain six equivalents of water ; those procured at
high temperatures, only three. They are fine blue prisms,
those containing six equivalents of water being paler
than those which have only three. They deflagrate on red
hot coals and behave generally like other nitrates. They
oxidate some metals very powerfully. Powdered, moist-
ened with a very small quantity of water, and wrapped
in tin foil, spontaneous ignition takes place.
Anhydrous nitrate of copper has been obtained. When
the crystals are heated, they lose water and nitric acid,
and are converted into a sparingly soluble basic nitrate,
of the formula 4CuO,N0 5 . If the heat is pushed, all
the acid is driven off and oxide of copper left.
With a small quantity of ammonia the basic salt is
precipitated, and with a larger proportion it is dissolved,
forming a blue solution, which deposits crystals of the
constitution, CuON0 5 ,2NH 3 . By passing ammoniacal
gas into a concentrated solution of nitrate of copper,
and carefully evapoi'ating, a compound of amide of cop-
60 CHEMICAL RELATIONS OF COPPEK.
per with nitrate of ammonia (CoNH 2 ,NH 4 ON0 5 ) is
formed.
CARBONATES OF COPPER.
The native carbonates will be described in the next
chapter. Of the artificial carbonates, the best knovm
is the
Bibasie Carbonate of Copper, 2CuOC0 2 ,HO. It
is obtained by treating a copper solution with an alkaline
carbonate, as a bulky, blue, gelatinous precipitate. If
this be gently heated with the supernatant liquor, it
assumes a granular form and a green color, and in this
condition, is sold as a pigment under the name of min-
eral green. If long boiled with the solution from which
it has been precipitated, all the carbonic acid is gradu-
ally driven off, and black oxide of copper is left.
An Ammoniacal Carbonate of Copper, CuO,C 4 H 3 3 ,
HO, has been obtained in fine blue needles, by dissolv-
ing the bibasic carbonate in ammonia, and adding al-
cohol.
Double carbonates with potassa and soda may be crys-
tallized from a solution of the bibasic carbonate in the
bicarbonate of either of the bases.
Borate of Copper is a pale green powder, slightly solu-
ble in water, fusing to a green glass. It may be obtained
by melting oxide of copper and borax together, and dis-
solving out the alkaline salt with Avater.
Silicate of Copper is green, and has been obtained
artificially by fusing oxide of copper with glass.
The salts with the halogens are of no special interest
nor importance.
CHEMICAL RELATIONS OF COPPER. 61
Tlft chlorate, formed by direct union of the oxide with
chloric acid, forms green deliquescent crystals. The
perchlorate, formed in the same way, is in blue deliques-
cent crystals. Like other chlorates and perchlorates,
they deflagrate with red hot charcoal. The iodate,
obtained in the same manner, or by double decompo-
sition, is sparingly soluble in water. The bromate is in
sea-green crystals.
ACETATES OF COPPER.
There are several combinations of oxide of copper with
acetic acid. One of these is neutral ; the rest are basic.
Neutral Acetate of Copper. CuOC 4 H 3 3 ,HO. This
salt is obtained by dissolving oxide of copper or verdi-
gris in acetic acid, or by precipitating acetate of lead
with an equivalent of sulphate of copper. By crys-
tallizing any of the solutions thus obtained, the salt
separates in dark-green, oblique rhombic prisms, with
oblique terminal planes. It is soluble in 13.4 parts of
cold and 5 of boiling water. In the air, it burns with a
green flame, and when distilled in close vessels it gives
off the various, products of the decomposition of vinegar,
and then strong acetic acid, leaving behind finely divided
and easily inflammable metallic copper. Mixed with
honey, sugar, &c. it is decomposed, small, red, octohe-
dral crystals of suboxide of copper subsiding, and formic
acid remaining in the liquid.
If the solution be made with dilute acid and crystal-
lized at a low temperature, the crystals are blue four-
sided prisms, containing 5 equivalents of water, 4 of
which are lost when the salt is heated.
6
62 CHEMICAL RELATIONS OF COPPER.
Commercially, this salt is prepared by dissolvin^'in. a
copper kettle, one part of verdigris in two of distilled vine-
gar, with the aid of a slight heat and constant agitation
with a wooden spatula. As soon as the liquid has attained
the greatest possible intensity of color, it is decanted
into well glazed earthen vessels, and fresh vinegar is
added to the residue. If this is not sufficient to saturate
the acid, more verdigris is added. The clear solution
is then evaporated to a syrupy consistence, and crystal-
lized around sticks in a room heated with stoves. As
thus obtained, the crystals are blue and rhomboidal.
Basic Acetates of Copper Bibasic Acetate of Copper.
Verdigris. The formula for this salt, as commonly writ-
ten, is CuO,C 4 H 3 3 CuO,HO,5HO, which assumes it
to be a compound of the blue neutral acetate with the
hydrated oxide. In reality, however, it is a very varia-
ble salt, and the analysis does not always correspond with
this theoretical constitution.
It is obtained by exposing sheets of metallic copper to
the mash of the grape, while it is undergoing the acetous
fermentation, or by wrapping them in cloths moistened
with acetic acid. There is a difference in the color of
the two products, that obtained by the former process
being blue, while the result of the latter operation is
green. It is a hard tough mass, varying in color from
a blue to a green, and decomposed by cold water into
two salts, presently to be described.
Tests. It should be dry, of a clear bluish green tint,
soluble in ammonia and diluted acetic acid, and when
ignited in a close vessel, it should leave a residue of
metallic copper mixed with carbon.
CHEMICAL RELATIONS OF COPPER. 63
Sesquibasic Acetate of Copper. 3Cu02(C 4 H 3 3 ),6HO.
When verdigris is treated with warm water, it is decom-
posed, and a blue amorphous mass, the sesquibasic acetate
remains behind, after spontaneous evaporation. Should
the solution have been previously mixed with alcohol,
this same salt is obtained in crystalline scales. When
heated to the boiling point, a concentrated solution
deposits a liver-brown powder.
Tribasic Acetate of Copper. 3CuOC 4 H 3 3 ,3HO. When
verdigris is exhausted of its soluble salts by digestion in
water, or when a solution of the neutral acetate is di-
gested with hydrated oxide of copper, a light green
tasteless powder, the tribasic acetate, is obtained. It
is the most permanent of the acetates of copper, losing
no water at 212. Boiled with water it undergoes the
same decomposition as the last named salt, the neutral
salt being found in the solution. Heated in the open
air it burns with feeble deflagration.
Hyperbasic Acetate of Copper. The formula for this
salt has been written, 48CuO,C 4 H 3 3 ,12HO ; but it
may well be doubted if there be any definite compound
of the kind. It is probably a combination of the oxide
with some of the other acetates. It is deposited as a
liver-brown powder when any of the other acetates is
boiled with water. When dry it is black and slightly
soluble in water.
Commercial Verdigris, is a variable compound of the
above named acetates. The greener varieties, according
to Berzelius, are principally made up of the sesquibasic
acetate, while the bibasic salt is the chief component of
the blue varieties.
64 CHEMICAL RELATIONS OF COPPER.
It is made in the south of France, by exposing copper
sheets to the action of the fermenting residue of the
grapes, the hulls, &c., which remain after the expression
of the must. This refuse is put into earthen vessels,
covered with lids and surrounded by straw mats to
retain the heat. Fermentation soon begins and the
temperature rises. The proper time for commencing
the operation is determined by introducing a slip of
copper as a test into the fermenting mash. This is
allowed to remain twenty-four hours, when, if it be
covered with uniform green layer concealing the whole
surface of the copper, all is ready for commencing the man-
facture. If, however, drops of liquid remain on the
surface of the metal, thfe heat is considered to be insuffi-
cient and the materials are allowed to ferment another
day.
fSlips of copper, 6 inches long by 3 broad, and weigh-
ing about 4 ounces, having been well beaten upon an
anvil, to remove all scales, consolidate the metal and
give it a smooth hard surface, are now heated over a
charcoal fire, and introduced into earthen vessels in
alternate layers with the fermenting materials, the top
and bottom strata being composed of the grape refuse.
From thirty to forty pounds of copper are put into each
vessel, the whole covered up with the straw mats and
left at rest. In from ten to twenty days the vessels are
opened and the plates examined, when, if they are
covered with glossy isolated crystals, they are placed
upright to drain, in a corner of the cellar, upon a
wooden floor. After two or three days they are moist-
ened by being dipped into water or spoiled wine, and
CHEMICAL RELATIONS OF COPPER. 65
then returned to the fermenting vats in the same order
as before. This operation is performed every week for
six or eight times.
In consequence of this treatment, the plates swell,
and become invested with a green layer of verdigris,
which is removed with a knife. In this condition, it is
called fresh or humid, and five or six pounds of it (i. e.
about 16 per cent.) are obtained from each vessel. It
is dried by kneading it in wooden troughs and suspend-
ing it in leathern bags where it can be fully exposed to
the action of the sun and air. It loses about half its
weight, and becomes so hard that a knife, driven through,
the bag, cannot pierce the loaf of verdigris.
A purer variety is made in some parts of France and
in England, by stratifying the copper sheets with layers
of cloth soaked in acetic or common pyroligneous acid,
in wooden boxes. The cloths are moistened with acid
every three days, until small crystals make their appear-
ance, which takes place in about twelve days. Tiiey are
then, as in the last described process, moistened with
water every week, the cloths removed, and a small space
left between the plates for circulation of air. The ope-
ration is finished in five or six weeks.
This substance is also made by putting rolls of sheet
copper in vessels containing vinegar, in the same manner
as plates of lead are treated in the manufacture of
white lead.
Uses. Verdigris has extensive applications in the
arts. It is used as a pigment in oil painting, and as
the basis of other pigments hereafter to be mentioned.
It is also employed in lacquering, in bronzing copper,
6*
66 CHEMICAL RELATIONS OF COPPER.
in calico printing as a resist-paste, in dyeing, especially
the dyeing of hats. The neutral acetate is used as a
green pigment. It was formerly employed in the manu-
facture of concentrated acetic acid. It has the same
applications to dyeing and calico printing, as the common
verdigris.
ARSENITES OF COPPER.
ScJieeles Grreen. When neutral salts of arsenious acid
and of copper are mixed, a fine green precipitate falls.
This is largely employed as a pigment. It forms that
peculiar delicate green so much used by paper stainers,
and has been applied to dyeing and calico printing, by
effecting the decomposition upon the fabric to be tinted.
It is made on the large scale by dissolving 3 parts of
carbonate of potassa and 1 of arsenious acid in 14 parts of
water, and by gradually adding this while hot to a boil-
ing solution of 3 parts of sulphate of copper in 40 parts
of watqr, the mixture being constantly stirred. The
exact hue of green may be modified by altering the
quantity of arsenious acid.
Schweinfurtli Grreen. When boiling solutions of ace-
tate of copper and arsenious acid are mixed, a bulky olive
green precipitate is immediately produced. If this be
boiled in the supernatant liquid, it changes its form and
color, becoming a dense granular powder of a beautiful
green tint. The same alteration takes place in the cold,
if time enough be allowed for the reactions. It is said
that the best result is obtained by adding to the hot
mixed solution its own bulk of cold water and allowing
it to stand, until the desired color is obtained, in a glass
globe filled up to the neck with the mixture. The com-
CHEMICAL RELATIONS OF COPPER. 67
mercial formula given by Kastner, as quoted by Ure, is
as follows : For 8 parts of arsenious acid, take from 9
to 10 of. verdigris; diffuse the latter through. water at
120 F., and pass the pap through a sieve ; then add
the arsenical solution and set the mixture aside till the
reaction of the ingredients shall produce the desired
hue. If a yellowish tint is required, more arsenious
acid must be used. By digesting Scheele's green in
acetic acid, a variety of Schweinfurth green may be
obtained.
This is a richer pigment than the last named. It is
useless to say that they are both very deadly poisons,
and the fact is only mentioned here to caution the
reader against the green candies sold by our confec-
tioners, many of which are colored with Scheele's green.
There is another arsenite of copper, 2CuOAs0 3 ,
which is precipitated by neither acids nor alkalies, and
which yields a yellowish green salt on evaporation. It
is made by digesting the oxide or the carbonate of
copper in arsenious acid.
SULPHO-SALTS.
A SubsulpJwphosphite of Copper is formed when bisul-
phide of copper is treated with sulphide of phosphorus,
and gently warmed in a current of hydrogen. It is a
yellow powder of the composition 2Cu 2 S,PS 3 . By
heating this, two equivalents of sulphur are driven off,
leaving 2Cu 2 S,PS.
The liyposulphopliosphite (CuS,PS) is obtained like
the last compound by using the sulphide of copper
instead of the bisulphide. Various salts are formed
from it by decomposing it through the agency of heat.
CHAPTER II.
ORES OF COPPER.
THE minerals into which copper enters as an essen-
tial ingredient are both numerous and important, but
lie, for the most part, out of the range of a book like
this. The working ores, as they are termed by smelters,
may be reduced to certain classes possessing distinct
outlines.
Native copper, though not an ore of copper in the
strict mineralogical sense of the word ore, has, never-
theless, a place in the smelter's classification and con-
stitutes a class by itself. The second class comprises
the native oxides and chlorides of copper. The third
class is occupied by the combinations of copper with
sulphur, selenium, arsenic and antimony. The silicates
form the fourth class, and the fifth class is taken up
with the remaining oxysalts of this metal.
CLASS I.
Native Copper may exist either crystallized, amor-
phous or in various imitative forms. When crystallized,
it belongs to the monometric, tesseral or cubic system of
crytallographers ; that is to say, whatever may be the
form of any given crystal, it is in every case a modifica-
tion of a cube, and can be referred to that figure. The
forms commonly enumerated arc the cube, the octahe-
ORES OF COPPER. 69
dron, the rhombic dodecahedron, the twenty-four hedron
and the fourxsix hedron, or cube replaced on every side
by a four-sided pyramid. I have also seen obscure pen-
tagonal dodecahedral crystals and every possible modifi-
cation and combination of these various forms. Very
often the matrix in which it is contained impresses its
own crystalline form upon the copper, so that the metal
is covered Avith indentations faithfully copying the pro-
jections of the crystals among which it lies embedded.
As this occurs sometimes in masses which are covered
with the proper crystals of copper, it constitutes quite a
puzzling phenomenon to the beginner in crystallography.
One of the most common, and at the same time most
beautiful forms of this metal, is that in which it is dif-
fused through the rock in a branching, arborescent form,
so that it resembles a great metallic lichen. Often it
will be found presenting this irregular plant-like form
on one side, while on the other it is covered with fine
crystals of the forms already described. It is also found
in great masses, in thin, films, and in broad sheets.
It is soft enough to be cut with a knife, its hardness
varying according to the commonly received standard,
from 2.5 to 3. Its specific gravity, when pure, is 8.74.
It possesses the color and lustre of fused copper,* and
like it is ductile and malleable.
Its behavior with chemical reagents is of course iden-
tical with that of metallic copper, however obtained.
Before the blow-pipe it fuses, becoming covered with a
coating of black oxide. It dissolves rapidly in nitric
acid, with effervescence and the escape of red fumes,
* It occasionally presents the various tarnishes already described
as occurring upon ingots.
70 ORES OF COPPER.
and gives a blue solution with ammonia. By these pro-
perties together with its malleability, it is easily distin-
guished from all other substances.
Native copper is very extensively distributed over the
earth's surface, being a common mineral in most copper
mines. Very fine crystals are obtained from the Faroe
isles and from Siberia. Cornwall contains considerable
quantities of it, and the South American mines also
furnish it. It is found abundantly in the United States.
In New Jersey it is quite common, especially at Schuyler's
mine, Flemington, Brunswick and Somerville. Near the
last named place, a mass was found weighing 78 pounds,
which is said originally to have weighed 128 pounds.
Near New Haven, Connecticut, a mass was found weigh-
ing 90 pounds. There is much native copper in Vir-
ginia, along the Blue Ridge, where it is commonly found
in broad sheets of variable thickness, coating epidotic
trap and filling up the seams in that rock. At Manassa's
Gap, in Fauquier county, it is diffused through the trap,
in combination with the two oxides and silicate of cop-
per. Its greatest masses, however, occur upon the
shores of Lake Superior.
The Lake Superior copper contains also native silver,
generally occurring in cavities of the copper. It is also
said to be alloyed with silver to the extent of 0.3 per
cent. ; but I have repeatedly analyzed specimens of this
copper, and only in a few instances have I discovered
the more valuable metal. Specimens there are undoubt-
edly which contain much more than that amount, but
the majority have only a trace of silver, and in many
fragments none at all can be detected. Hautefeuille
has recently detected mercury in this copper.
ORES OF COPPER. 71
CLASS II.
Red Copper may be massive, granular, earthy, or
crystallized. Its crystals belong to tbe same system as
native copper. When pure, it is usually of a fine co-
chineal red color, though it is occasionally crimson,
especially by transmitted light. Sometimes, however,
the opaque crystals have an iron-gray tint upon the sur-
face, resulting probably from oxydation ; but even in
this case, the red color shows itself when the crystal
is pulverized. The finest specimens are transparent,
and have a rich ruby hue.
"When massive, it is usually found in connection with
native copper and the black oxide. It occurs mingled
with metallic copper and the black oxide, above and
between the bricks of a refining furnace. Many beau-
tiful specimens may be obtained from such spots, the
clear ruby red of this compound contrasting finely with
the rich steel gray of the fused black oxide. Tile ore
is an earthy variety, usually brownish or dark brick
red. It is mixed with a variable amount of red oxide
of iron. In Cornwall, and at Rheinbreitenbach, on the
Rhine, it is found in capillary crystallizations, to which
the name cJialclwtricJiite has been given.
This oxide is found in many mines, the finest crys-
tals being obtained from Chessy, Moldawa, and Eka-
therinenburg. Cornwall, especially at Huel Garland
mine, near Redruth, furnishes octahedral crystals. In
this country, it has been found, in the New Jersey
mines, in the Tennessee and Virginia mines, and at
Manassa's Gap, in Virginia.
72 ORES OF COPPER.
The composition of this ore, according to an analysis of
Chenevix, is :
Copper, - - 88.78
Oxygen, - 11.22
Its formula is Cu 2 0, and its specific gravity 5.992.
Before the blowpipe, in the reducing flame on char-
coal, it affords a globule of copper. It dissolves in hot
muriatic acid, excluded from the air, forming a colorless
solution, which gradually becomes green when exposed
to the atmosphere. In nitric acid it dissolves with effer-
vescence, forming a blue solution. From its hydrochloric
solution, water throws down a white, and potash a yel-
low precipitate.
Black Oxide of Copper is commonly found in powder
or friable masses, of an earthy appearance, mixed with
sulphurets, arseniarets, &c., resulting from atmospheric
action upon the other ores of the vein. It is occasion-
ally found massive, containing crystals of cubic or allied
forms. Its lustre may be submetallic and earthy, or
metallic and bright. Beautiful steel gray specimens may
be obtained from the hearth of an old refining furnace.
Tenorite is a variety found in the lava of Vesuvius,
in small scales, hexagonal or triangular in form, of a
dark steel-gray hue by reflected, and brown by trans-
mitted light.
The black oxide is found coating many different ores,
and is a product of most mines. In Polk county, Ten-
nessee, however, it exists in great quantities, beds of it,
from 25 to 90 feet in thickness, being worked there.
At Keweenaw Point, Lake Superior, the compact vari-
ety has been found, and at Manassa's Gap, in Virginia,
ORES OP COPPER. 73
it occurs massive, mixed with native copper, red oxide,
and chrysocolla,
Its composition is :
Copper, - 79.86
Oxygen, - 20.13
Its formula is CuO, or Cu. Its specific gravity va-
ries, of course, with its state of aggregation. That of
Keweenaw Point, is stated, by Dana, on the authority of
a private communication from Teschemacher and Hayes,
to be 5.140 for the crystals, and 5.386 for the compact
portions.
It dissolves with a green color in muriatic acid,
and without effervescence in nitric acid. Its blowpipe
reactions are the same as those of the last variety.
Atacamite is a beautiful emerald, or blackish green
mineral, found in Chili and Bolivia. Its system of
crystallization is trimetric, and it usually occurs in rec-
tangular prisms or rectangular octahedra. It is also
found massive.
It was originally found, in the state of sand, in the
desert of Atacama, between Chili and Peru, whence its
name. It also occurs' at Los Remolinos, in Chili, at
Cobija, in Bolivia, and coating the lavas of Vesuvius
and Etna.
Its composition varies according to different observers.
We give two per centage statements:
Chloride of Copper, - 31.48 27.94
Oxide of Copper, - 55.94 49.57
Water, - - 12.58 22.49
100.00 100.00
74 ORES OF COPPER.
Its formula, therefore, is CuCl+3CuO+3HO, or
CuCl+3CuO+6HO.
It tinges the blowpipe flame green or blue, and gives
off fumes of hydrochloric acid ; and, on charcoal, yields
a bead of metallic copper. It is soluble in acids.
CLASS III.
Copper Grlance, or Vitreous Copper, called also Sul-
phuret of Copper, is of an iron gray or blackish lead-
gray color, often tarnished with blue or green, and
sometimes iridescent. Its crystals belong to the tri-
metric system. The primitive form is a six-sided prism,
but it is commonly found in hexagonal tables. It is
more frequently met with massive. It is very soft and
friable, may be readily cut with a knife, and when
scratched, gives a shining streak the color of the ore.
It is very fusible, melting in the flame of an ordinary
candle.
Fine crystals of this species are found in Cornwall,
especially in the neighborhood of Redruth, whence one
of its names, Redruthite. It occurs massive, in nume-
rous localities, both in Europe and the United States.
Crystals, of fine size and great brilliancy, have been
found at the Bristol mine, in Connecticut.
The composition of this mineral, when pure, is :
Copper, 79.8
Sulphur, 20.2
100
Usually, however, it is contaminated with iron, which
ORES OF COPPER.
75
makes it harder and more infusible. Thompson's analy-
sis of a Cornish specimen is as follows :
Copper, - 77.16
Sulphur, - 20.62
Iron, 1.15
98.93
It is, therefore, a sulphuret of copper, its formula
being CuS. Its specific gravity varies from 5.5 to 5.8.
Before the blowpipe, in the outer flame, " it melts,
gives oif fumes of sulphur, and emits glowing drops with
a noise, coloring the flame at the same time blue. In
the inner flame, it becomes covered with a coating, and
does not melt." The blue tinge of the flame is espe-
cially observed, if the specimen has previously been
moistened with hydrochloric acid. On charcoal, it gives
off fumes of sulphurous acid, and leaves a bead of cop-
per. In nitric acid it dissolves to a green solution, floc-
culi of sulphur floating through the liquid.
Harrisite, This has been described by Prof. C. H.
Shepard as a new mineral species. It is regarded by
Genth as a pseudomorph of copper-glace after galena.
It occurs at the Canton mine, Cherokee county, Geor-
gia, in forms closely resembling those of galena. My
specimens are of a dark iron-gray, with perfect cubical
cleavage down to the smallest fragment. Some of
them have the foliated character of which Dr. Genth
speaks, and most of them are curved as though they
had been bent after they had been deposited.
The following are the results of two determinations
by Dr. Genth :
76 ORES OF COPPER.
Sulphur, 20.648 20.647
Selenium, not determined 0.047
Silver, 0.207 0.164
Copper, 77.298* 77.758
Lead, 0.056 0.060
Iron, 0.442 0.359
Insoluble, - 0.272 0.667
98.923 99.702
Sp. gr. 5.485. H. 3 to 3.5.
Digenite is an allied mineral, found in Chili, and at
Saugenhausen, in Thuringia. Its specific gravity is
4.6. It is supposed to be a mixture of copper glance
and covelline.
Berzelianite is a selenide of copper, occurring in thin
dendritic crusts, of a silver-white color and a metallic
lustre. It is found in Sweden and the Hartz mountains,
and is of no value as an ore.
Covelline, or Indigo Copper, is found in crystals be-
longing to the hexagonal system, and also massive or
spheroidal, with a crystalline surface. Its color is
indigo blue, its lustre resinous, its streak lead-gray and
shining. Before the blowpipe it burns with a blue
flame before becoming red hot, and fuses to a globule,
which is strongly agitated and emits sparks, finally
yielding a button of copper. Its composition is Copper
66.5, Sulphur 33.5.
Cantonite. A pseudomorph of Covelline has been
described under this title by N. A. Pratt, Jr. He says
* Some accidentally lost.
ORES OF COPPER. 77
it is found finely crystallized in well-formed cubes, of
submetallic lustre and blue-black color, and gives its
specific gravity as 4.18, and its hardness as 1.5 to 2.
His analysis (No. I.) may be compared with Dr. Genth's
(No. II.)
i. 11.
Sulphur, 33.490 32.765
Copper, 66.205 65.604
Selenium, ^j - trace
Silver, 0.355
Lead, .305 0.107
Iron, 0.251
Insoluble, J - 0.157
100.00 99.239
Genth calls it a pseudomorph of Covelline, after Ga-
lena.
JEnibescite, Phillipsite, Variegated Copper, or Purple
Copper, belongs to the monometric system of crystalli-
zation. Its crystals are ill-defined, and usually cubes
or octahedra. Most frequently it occurs granular or
compact. Its lustre is metallic, its color, in fresh frac-
tures, reddish-brown, something between copper and
pinchbeck, and it is commonly tarnished with different
hues of blue, purple, and red. It is brittle, and breaks
with an uneven, small conchoidal fracture.
It is an important ore of copper, being found in Corn-
wall, Killarney, Tuscany, Mansfield, Norway, Silesia,
Siberia, and the Bannat. It also occurs in Pennsylva-
nia, Massachusetts, Connecticut, and New Jersey, and
in most of the mining districts of South America.
7*
78 ORES OF COPPER.
Its composition is :
Berzelius. Kammelsberg.
Copper, - 62.5 55.5
Iron, 13.8 16.4
Sulphur, - - 33.7 28.1
100.0 100.0
Analysis of different specimens differ still more
widely than these two statements, the copper ranging
from 71 to 56 per cent. This may be accounted for
by supposing it to be variously mixed with other ores of
copper. The only two analyses of crystals approach
much nearer Rammelsberg's than Berzelius' table. Its
formula, according to Berzelius, is 2Cu 2 S+FeS, and
according to Rammelsberg, 3Cu 2 S+Fi 2 S 3 .
Before the blowpipe it blackens and becomes red on
cooling, or if sufficiently heated, fuses to a black glo-
bule, which is attracted by the magnet.
Barnhardite is a new mineral, described by Dr.
Genth, of Philadelphia. It occurs in compact masses.
Specific gravity, 4.521 ; lustre metallic, but somewhat
dull ; color bronze-yellow ; streak grayish black and
slightly shining ; opaque ; fracture conchoidal, uneven ;
tarnishes very soon more readily in presence of mois-
ture, assuming a peculiar brownish, sometimes pinch-
beck-brown ; sometimes, also, rose-red and purple color.
Before the blowpipe, gives off sulphurous acid, and
fuses easily to an iron-black magnetic globule ; and with
borax, it gives the relations of copper and iron ; with
carbonate of soda and borax, metallic copper. The
calculated composition is as follows :
ORES OF COPPER. 79
Copper, - 48.14
Iron, 21.33
Sulphur, - 30.53
The formula is 2Cu 2 S+Fe 2 S 3 .
"I have found this mineral associated with other
copper ores at Dan. Earnhardt's land, (hence its name,)
and Pioneer Mills, Cabarrus county ; Dr. 0. Dieffen-
bach observed it in the Phcenix and -Vanderburg mines
of the same county, and I saw it also amongst copper
ores from the neighborhood of Charlotte, Mecklenberg
county, N. C. It seems to be abundant in North Caro-
lina, and is, of course, a very valuable copper ore."*
Copper Pyrites is a yellow ore, with a brilliant metal-
lic lustre, and is often mistaken by the inexperienced for
native gold. It usually occurs massive, having an
irregular and slightly conchoidal fracture. It is also
found botryoidal, globular, stalactitic, and crystallized.
Its crystals are octahedral or tetrahedral, and belong
to the dimetric system. It is liable to tarnish, and is
sometimes iridescent. Its streak is greenish black and
shining, and its powder is a fine bronze green.
This is the most abundant of all the ores of copper.
It is the principal product of the Cornish mines, which
yielded, in 1853, 180,000 tons of ore. It is also worked
in Scotland, Sweden, Germany, Hungary, Australia.
In the United States, it is a very frequent accompani-
ment of galena, and is also found alone in numerous
places. It is worked in several of the States, but its
localities will be described in the chapter on Mines.
-- American Journal of Science and Art, January, 1855, p. 18.
80 OHES OF COPPER.
Its composition is :
Copper 34.47
Iron 30.48
Sulphur - 35.05
100.00
Its formula is Cu 2 S-f Fe 2 S 3 . Its specific gravity varies
from 4.1 to 4.3.
Before the blowpipe, at a low heat it blackens, but
becomes red on cooling, in consequence of the oxidation
of its iron. At a higher heat, it fuses to a black, brittle
globule, which is attracted by the magnet, and if the
heat be kept up long enough, upon charcoal, it yields a
metallic globule. Fused with a small quantity of borax,
it also furnishes a bead of pure copper. Nitric acid
forms with it a green solution, having sulphur in the
liquid.
This ore need not be mistaken for anything else. It
is easily distinguished from gold by the fact that it is
not malleable. From iron pyrites it may be distinguished
by its color, which is a rich golden yellow, while that is
a pale brass-color, and also by its softness, iron pyrites
being hard enough to strike fire with steel. It is, how-
ever, often intermixed with this other mineral, and then
it is both paler and harder than the pure variety. The
action of nitric acid is also characteristic.
The copper pyrites of commerce is a very variable
ore, and it is not always easy for the most experienced
to determine its value by simple inspection. It is com-
monly largely mixed with silicate of copper, malachite,
iron pyrites and quartz, and some of the poorest ores,
ORKS Oi 1 COPPER. 81
when pounded up and dressed, can hardly be distinguish-
ed from the best. There is a very deceptive ore of this
kind in Louisa county, Virginia. It is essentially an
iron-pyrites with sufficient copper diffused through it,
to give it the black tarnish common on the rich Cuba
ores, and yet samples of it, when dressed and sent to
market, though looking very well, have furnished only
between from one and two per cent, of copper. * ,
Domeylcite, or arsenical copper is a tin-white, slightly
yellowish mineral, often presenting an iridescent tarnish,
occurring in reniform and botryoidal inasses, as well as
massive and disseminated. It is found in Chili and
in Cornwall. It is composed of arsenic 28.3, copper
71. 7. Before the blowpipe it fuses, giving off the gar-
licky color of arsenic.
Oondurrite, a- mixture of domeykite, with red copper
ore and arsenite and sulphuret of copper, is greenish-
black or blue in color, and soft in texture.
G-ray copper, fahlerz of the Germans, usually occurs
massive, but is also found in cubes and tetrahedra,
belonging to the monometric system. Its color varies
from steel-gray to iron-black, and its streak is the same
color or slightly brownish. It is brittle and has a con-
choidal fracture.
In composition it is a very variable mineral, as the
following table will show :
* Breithaupt describes a variety of this pyrites under the name of
Cuban, occurring in cubes or massive. Its color is between bronze
and brass-yellow, its streak black, its hardness 4 ; its specific gravity,
4.026. It contains 19 per cent, of copper, fuses easily before the blow-
pipe, giving off fumes of sulphur but no arsenic. His specimens came
from the Island of Cuba. I have seen it occasionally in cargos of ore
from the West coast of South America.
ORES OF COPPER.
s
m Clausthal,
Iphur. Antimony
24.73 28.34
Arsenic
Copper
34.48
Iron. Zinc. Silver. Gold. Quartz.
2.27 5.55 4.97 " " Rose.
' Wolfacli,
23.52
26.63
"
25.33
3.72 3.10 17.71 "
" Rose.
' Corbiers,
25.30
25.00
1.50
34.30
1.70 6.30
0.70 "
" Berthier.
' Gersdorf,
26.33
16.52
7.21
38.63
4.89 2.76
237 "
" Rose.
' Unknown,
10.00
"
14.00
48.00 25.50 "
0.50 "
" Klaproth.
' Cabflrrus )
25,48
17.76
11.55
30.73
1.42 2.53
10.53 "
" Genth.
Co. N.C. )
" Bucking- )
28.46
5.10
16.99
40.64
4.24 3.39
0.42 Tract
1.24 Taylor.
From this table, it would appear impossible to con-
struct anything like a formula for this mineral. It is
usually said to be 4(Ag,Cu 2 ZnFe)S and (As,Sb)S 3 ,
but it is manifest that neither this nor any other
can apply. Dr. Gentli considers his specimen from
Cabarrus county a new species, and offers for it the
formula 5(Ag,Cu 2 ,Zn,Fe)Sx2(As,Sb)S 3 . Rose thinks
that the general composition of the mineral may be
represented by the formula Fe 4 Cu 16 Sb 6 S 21 , in which each
of the different metallic substances may be, to a greater
or less extent, replaced by others, so that sulphuret of
antimony may be substituted by sulphuret of arsenic,
and sulphuret of copper by sulphuret of silver.
The blowpipe reactions must necessarily vary some-
what. They usually, however, consist in the evolution
of fumes of antimony and arsenic, the former recognized
by its white smoke, and the latter by its garlicky odor.
With this is combined the odor of sulphuric acid from
the sulphur present. The coal will be covered with the
white incrustation of antimony, or if zinc be present by
a yellow sublimate, becoming snow-white on cooling.
"When finely powdered, it dissolves in nitric acid, leaving
a slight residue, and forming a brownish-green solution.
Dr. Genth gives the following as the re-actions of his
Cabarrus county ore. "Before the blowpipe, decrepi-
tates slightly ; in an open tube disengages sulphurous
ORES OP (JOPPER. 83
acid, gives a sublimate of arsenious acid ; on charcoal it
emits fumes of an alliaceous odor and covers it with
white incrustations ; it fuses into a magnetic globule and
gives with fluxes the re-actions of copper and iron."
This is a very important ore of copper, and is additi-
tionally valuable from the silver it contains. It occurs
in fine crystals near Cornwall, near St. Austell, though
their surface is commonly rough and dull. More bril-
liant crystallizations are found at St. Andreasberg in the
Hartz ; Kremnitz, in Hungary ; Freyberg, in Saxony ;
Dillenberg, in Warsaw ; and Kapnik, in Transylvania.
It is found massive in the Tyrol, and in Siberia. In the
United States, according to Dr. Genth who first discov-
ered it in this country, it occurs in Cabarrus county,
North Carolina ; at Eldridge's gold mine in Buckingham
county, Virginia ; and in Duchess county, New York.
Tennantite has a close resemblance to gray copper,
and occurs in brilliant crystals investing other ores of
of copper. It is found in Cornwall and Norway.
Wolfsbergite, or antimonial copper, is a sulphantimcr-
niate of copper, occurring in small aggregated tabular
prisms, in quartz, at Wolfsberg in the Hartz.
Bournonite is a gray or blackish mineral, crystallizing
in prisms, belonging to the trimetric system. Its lustre
is metallic, its fracture conchoidal and uneven.
Rose's analysis of a specimen from Pfafienberg, is :
Copper, ir* 12.65
Lead ifsi: 40.84
Antimony - - 26.28
Sulphur - ri^fr in* 20.31
100.08
84 ORES OF COPPER.
Before the blowpipe, it fuses to a black globule, and
gives off fumes of antimony. At a high heat the charcoal
is coated with a yellow deposit of oxide of lead. It dis-
solves easily in nitric acid, forming a blue solution.
It is found in several of the European mines, but has
not yet been discovered in this country.
CLASS IV.
Dioptase is a rare and beautiful emerald green, trans-
parent or translucent mineral, occurring in rhombohedral
crystals, in quartz, at Altyn Tube*, in Siberia. Its lustre
is various, its streak green, and its fracture conchoidal
and uneven. It is a silicate of copper, containing 3
equivalents of oxide of copper, 2 of silicic acid, and 3 of
water.
Chrysocolla is a silicate of copper, occurring usually
as an incrustation, but sometimes disseminated through
quartz. It has various tints of blue and green, from a
turquoise color to a bright mountain-green. It is some-
times brown from admixture of foreign ingredients, espe-
cially iron. The translucent varieties are hard and brit-
tle, the opaque ores soft and earthy. It is often mixed
with other ores, especially with the carbonates of cop-
per.
It is a very common ore of copper, and attends almost
every deposit of that metal which has a silicious vein-
stone. It is in primitive regions, especially in granite,
a frequent surface indication, being often diffused through
the quartz rocks, so as to give them a decided green
stain. At Manassa's Gap, it envelops the native copper
and the oxides of copper which are diffused through the
quartz.
ORES OF COPEER. 85
Its composition is :
Silica *$*, 34.82
Oxide of copper *:- 44.83
Water - 20.35
Its formula is 3CuO,2Si0 3 +6HO. Its specific gravity
is from 2 to 2.238. Before the blowpipe, on charcoal,
it blackens in the inner flame but does not melt. With
borax, it fuses to a green glassy globule, containing some
specks of metallic copper.
CLASS v.
Azurite occurs in beautiful azure blue crystals, belong-
ing to the monoclinic or rhomboidal system. These are
transparent or subtranslucent, having a glassy or ada-
mantine lustre, and a conchoidal fracture. The streak
is a lighter blue. It also is found in mamillary concre-
tions, and in dull earthy masses.
The finest crystals come from Chessy, near Lyons ;
though excellent specimens are found in the Bannat, in
Siberia, and in Cornwall. In this country it is found
at Perkiomen, near Philadelphia, and at other places
in Pennsylvania. It is also to be obtained near Sing
Sing, in New York, and near New Brunswick, in New
Jersey.
Its composition is
Oxide of copper .^ 69.09
Carbonic acid ....- j, - 25.69
Water 5.22
100.00
86 ORES OF COPPER.
Its formula is 2CuO,C0 2 +CuO,HO; its specific grav-
ity 3.5 to 3.831. Before the blowpipe, in the oxidating
flame, it is reduced to a black globule. In the
reducing flame in the loop, it burns with a green flame,
and on charcoal is reduced to metal. Heated in a glass
tube, it gives off" water and becomes black. Fused with
borax, it forms a green glass. It dissolves in ammonia
and the acids, effervescing with the latter.
It has been ground to a powder and used for paint,
but is liable to turn green.
Malachite is a mineral of various shades of green,
mostly emerald. It is found in crystals belonging to the
monoclinic system, but more commonly occurs in botryoi-
dal masses, which are often radiated, and sometimes
made up of minute crystals. Occasionally they seem to
have been formed in successive layers, the boundaries of
which are distinctly seen on breaking the mass. I have
some specimens from Patapsco mine, in Carrol county,
Maryland, which form beautiful green fibrous cones, an
inch or more in height, imbedded in a soft, red, ferru-
ginous mass. It is also found in a friable and pulveru-
lent state, when it is commonly mixed with various
earthy impurities.
It is met with in great masses in Siberia, and it has
been wrought into table-tops, &c. The Emperor of Rus-
sia, some years since, presented the King of Prussia
with a pair of beautiful vases, of great size, made of this
material. It is valuable not only as an ore of copper,
but also as a precious stone, being wrought by the lapi-
dary into numerous articles of jewelry. It is a very
convenient form for the manufacture of blue vitriol, and
ORES OF COPPER. 87
is also ground into a paint for the use of artists. In
smaller quantities, it is an accompaniment of almost
every ore of copper.
It composition is
Oxide of copper - 71.82
Carbonic acid - 20.00
Water - - - 8.18
100.00
Its formula is 2CuO,C0 2 +HO. Its reactions are
the same as those of azurite. Its specific gravity is
from 3.7 to 4.008. It is often mixed with lime, zinc,
and other substances, and these mixtures have occasi-
onally been described as distinct minerals.
Blue vitriol has already been sufficiently described in
the previous chapter. It is found at most mines of the
sulphurets of copper, as a consequence of the oxidation of
these ores, and the subsequent solution and crystalliza-
tion of the resulting salt of copper. It is of course
impure from the presence of iron. At some mines, the
blue water running from the ore is collected in cisterns,
into which scrap-iron is thrown. This precipitates the
copper which is slowly oxidated, so that a mixture of red
oxide and metallic copper is the result, a compound
easily and cheaply reduced to the metallic state.
BrocJiantite is a mixture of sulphate of copper and
the hydrated oxide, in the proportion of one of the former
to three of the latter. Its lustre is vitreous, its color
emerald-green or blackish-green, its streak is paler. It
occurs in transparent crystals, belonging to the trimetric
system, also in masses and botryoidal concretions.
88 ORES OF COPPER.
Lettsomite is a velvety blue coating on an earthy
hydrated oxide of iron, occurring sparingly at Moldawa
in the Bannat. It is a mixture of the sulphates of
copper and alumina, the oxide of copper and water.
Oonnellite is a blue, translucent mineral, with a vitre-
ous lustre, occurring in hexagonal prisms in Cornwall.
It is a mixture of the sulphate and the chloride of
copper.
Thrombolite is an amorphous, green, opaque phos-
phate of copper, with a vitreous lustre, found at Retz-
banya, in Hungary.
Before the blowpipe, it colors the flame first blue and
then green. On charcoal it fuses easily to a black
globule, and then yields a bead of copper.
Phosphorochalcite is a dark green, translucent phos-
phate of copper, found at Rheinbreitenbach, Nischne
Tagilsk and Hirschberg.
Libethenite is an olive-green, subtranslucent phosphate
of copper, having a resinous lustre and a subconchoidal
fracture. It belongs to the trimetric system of crys-
tallization. It is found in Hungary, Cornwall and the
Ural Mountains.
Olivenite is a phosphate and arseniate of copper, of a
dark green or brown color, crystallizing in forms belong-
ing to the trimetric system, and also occurring in globu-
lar, reniform and fibrous concretions.
Euchroite is a bright emerald or leek-green mineral,
found at Libethen, in Hungary, in large crystals. It
contains 33 per cent, of arsenic acid, and 54 of oxide of
copper.
Tyrolite is a pale green mineral, composed of arse-
OKES OF COPPER. 89
niate of copper, carbonate of lime and water. It occurs
in the cavities of calamine, calc-spar or quartz, accom-
panied by other ores of copper, appearing in small ag-
gregated and diverging fibrous groups, possessing a
delicate silky lustre.
Erinite occurs in mamillated, crystalline, roughened
coatings, made up of several layers often easily separa-
ble. Its color is a fine emerald-green, inclining to grass-
green, its streak paler. It contains 33.78 per cent, of
arsenic acid, 59.44 of oxide of copper, 5.01 of water,
and 1.7T of alumina. It is found in the county of
Limerick, in Ireland.
Aphanesite is of a dark green color, inclining to blue,
and sometimes to dark blue. Its crystals are brilliant,
but small, and belong to the monoclinic system. It is
found in Cornwall and in the Erzgebrige, and contains
30 per cent, of arsenic acid and 54 of oxide of copper.
CHAPTER III.
ANALYSIS OF COPPER ORES.
IN the first chapter we have given an account of the
reactions of pure copper. It is only necessary to bear
these in mind, to be able to recognize this metal. Still,
as there are some precautions to be observed in getting
the solutions to be operated upon, it may be well to give
here a brief account of the method of proceeding in the
qualitative examination of a mineral supposed to con-
tain copper, before undertaking to describe the quantita-
tive analysis of such ores.
This will vary very much with the nature of the
metals which may happen to be combined with the
copper. If, for example, the presence of lead be sus-
pected, the ore must be treated with dilute nitric acid.
It is best to take a mixture of one part of acid with five
or six of water, and allow it to stand on the ore at a
gentle heat, until the flakes of sulphur which havejiepa-
rated are of a clear yellow color. Should there be any
other insoluble matter left, the solution must be poured
off, the residue well washed, and then treated with boil-
ing concentrated nitric acid, until nothing is left un-
dissolved but the vein-stone and the floating sulphur.
The two solutions are now mixed, and to them is added
a little sulphuric acid. A white precipitate immediately
falls, which is indicative of the presence of lead.
It must, however, be borne in mind that lime also
ANALYSIS OF COPPER ORES. 91
produces a white precipitate with sulphuric acid, and the
tyro may be easily deceived. He will, therefore, remark
that the lead salt is the heavier of the two, that it dis-
solves readily in boiling muriatic acid, and that the
solution on cooling, deposits crystals. A more decided
distinction is the action of sulphureted hydrogen or
sulphide of ammonium. The white precipitate must be
thoroughly washed upon a filter, and then subjected to a
stream of sulphureted hydrogen gas, or moistened with
a solution of sulphide of ammonium. A dark brownish
black color is produced if the salt be one of lead,
whereas, sulphate of lime, when pure, is unaffected by
either of these tests. Thorough washing is essential,
because other metals, soluble in nitric acid, are black-
ened by these reagents.
If the copper ore, under examination, should be sup-
posed to contain silver, that question is determined by
dissolving the ore in nitric acid, filtering, and to the
clear solution adding muriatic acid or a solution of salt.
Immediately a white curdy precipitate falls, or if the
quantity of silver be small, a milkiness shows itself in
the liquid. This precipitate also needs to be closely
scanned, for lead is precipitated by hydrochloric acid.
The lead salt, however, is heavier, subsides more rapidly,
and is crystalline in its texture. It may also be dis-
solved in a large quantity of hot water, and crystallizes
out of this solution on cooling. The silver salt, on the
other hand, is curdy, subsides slowly, and is not soluble
in hot water. It turns purple or dove-color on exposure
to light, and dissolves readily in ammonia, whereas the
lead salt is insoluble in that reagent, and is not affected
by light.
92 ANALYSIS OF COPPER ORES.
Should the two metals co-exist, they will both be pre-
cipitated, and must be separated in the dry way, by
cupellation, hereafter to be described.
The presence of gold is detected, by dissolving the
ore in aqua-regia, (nitro muriatic acid,) and adding a
solution of sulphate of iron, when the precious metal
falls in a blackish brown powder. Some precautions
are necessary in this process to insure success. The
solution must be carefully evaporated to dryness over
the water bath, and then moistened with hydrochloric
acid. This process must be repeated several times,
until no more fumes of nitrous acid are given off, and
the solution must be diluted.
The most common way of detecting the presence of
copper in a mineral is to dissolve the ore in boiling aqua-
regia, filter and add to the filtrate a solution of ammonia.
Iron, if present, falls as a greenish or red-brown mud,
and the supernatant liquor has a very fine blue color.
Here too it is necessary to guard against mistakes.
Nickel also gives a blue solution with ammonia. The
experienced eye, however, can hardly be deceived, for
the solution of nickle is a pale sapphire blue, while that
of copper is a deep ultramarine. Even in diluted solu-
tions, this difference is observed.
The test with polished iron is not liable to these
objections. Even in very dilute solutions of copper, a knife
blade or a piece of clean wire is so completely coated,
that it appears to be converted into copper. One
part of copper in 180,000 of solution can be distinctly
recognized in this manner.
In some rare cases, nitro-muriatic acid will not dis-
ANALYSIS OF COPPER ORES. 93
solve the powdered mineral containing copper. It is
then necessary first to fuse the mineral with carbonate
of soda, and then to subject it to the action of the acid
and proceed as before.
The blowpipe methods have been described in the last
chapter.
A common way of determining the presence of copper
in an ore is to mix it with carbonate of soda, pearlash or
other alkaline flux, intimately mixed with finely powdered
charcoal, and to heat it nearly to whiteness in a crucible,
by the fire of a smith's forge. After keeping it at this
heat for some ten or fifteen minutes, or until the con-
tents of the crucible are in quiet fusion, it is taken off,
allowed to cool, and when the crucible is broken, a but-
ton of copper, enveloped in a gray, shining coating is
usually found below the flux.
It can hardly be necessary to say that in all these
processes it is necessary that the ore should be reduced
to the finest possible powder, before it is subjected to
the operations recommended.
If it be designed to make a systematic investigation
of all the contents of a copper ore, the following methods
should be resorted to.
The ore must first be heated gently with dilute nitric
acid, as before described. It is then, after everything
soluble in the dilute acid has been taken up, to be boiled
with concentrated nitric acid, until the separated sul-
phur, if there be any present, has assumed a clear yellow
color. These two solutions are poured off from the
insoluble residue, and mixed together and filtered. We
will call this solution No. I. Should the residue be
94 ANALYSIS OF COPPER ORES.
white, and it be desired to determine the presence of
the earths, it must be boiled with hydrochloric acid.
Should it be colored, first hydrochloric, and then nitric
acid is to be added and the boiling continued. The
whole is then evaporated to dryness over a water-bath,*
moistened with hydrochloric acid and drenched with dis-
tilled water. It is now filtered from the insoluble resi-
due, and constitutes solution No. II. Should the residue
still be colored, it is to be washed thoroughly with hot
water, and treated as we shall presently describe.
To the solution No. I. hydrochloric acid is added.
Should a white precipitate, which does not dissolve or
diminish on the further addition of acid, be thrown down,
it indicates the presence of lead, mercury or silver, or all
three. It must be well washed with cold water, and
then heated with a large quantity of water. If sulphuric
acid throws down a heavy white precipitate from this
hot solution, the presence of lead is established. Should
a portion remain undissolved, it is to be heated gently
with excess of ammonia. The blackening of the preci-
pitate indicates mercury. The ammoniacal solution is
decanted from the residue, if there be any, and mixed
with dilute nitric acid until a piece of litmus paper, dip-
ped into it becomes red. If there should fall a white
curdy precipitate, becoming purple by exposure to light
and dissolving in ammonia, silver is present.
The liquid filtered from the first precipitate is added
to No. II, and a stream of sulphureted hydrogen gas is
* This can easily be made extemporaneously by placing an evapor-
ating dish, or even a common saucer, over a tin cup containing water,
which is to be kept boiling.
ANALYSIS OF COPPER ORES. 95
passed through the mixed solutions. This is obtained
by adding dilute sulphuric acid to sulphuret of iron;*
the operation being conducted in a bottle fitted with a
cork and a bent glass tube which conveys the gas into
the solution. A black precipitate immediately falls, and
the gas is passed through till nothing more is thrown
down, and the liquid smells strongly of it. The whole is
then to be subjected to rapid filtration, taking care that
during the whole process the liquid is charged with sul-
phureted hydrogen, which may be known by the smell.f
The filtrate we shall call solution No. III.
The sulphides likely to be found in the precipitate, are
those of antimony, arsenic, bismuth, cadmium, copper
and gold. The latter must be sought in the original
solution as already described. The precipitate being
well washed, is put into a small flask and boiled with
yellow sulphide of ammonium,! when the first two sul-
* This re-agent is easily obtained by heating a bar of iron to bright
redness and holding against it a roll of brimstone. Sparks are emitted
and globules fall, which are caught in a pail of water. These are
found to be partly yellow and partly gray. The latter are selected.
A better way of preparing this compound, is to mix intimately 36 parts
of clean iron filings with 21 of flowers of sulphur, and throw them by
small portions at a time into a red hot crucible.
f It may be proper to state here that writers usually recommend
great caution in manipulating with this gas, as it is usually reputed
to be a powerfully sedative poison. I think, however, that its danger-
ous properties have been considerably exaggerated, as no particular
caution has ever been observed in its use in my laboratory, and no
accident has occurred there from it.
J This reagent, when recently prepared, is colorless, but, after
standing a while, becomes yellow or even red from separation of
sulphur. The latter modification differs, in some essential particulars,
from the former.
96 ANALYSIS OF COPPER ORES.
phides will be dissolved. The solution is separated by
filtration from the precipitate, care being taken to Wash the
latter thoroughly with water charged with sulphide of
ammonium. The clear filtrate is now mixed with excess of
dilute hydrochloric acid, and a little water saturated with
sulphureted hydrogen. The sulphides are re-precipitated,
and after being thoroughly washed, are agitated with a
solution of carbonate of ammonia, which must be allowed
to remain on them, at a gentle heat, for about fifteen
minutes. The solution contains the arsenic, if any be
present, and it will be detected by the yellow precipitate
which falls when a stream of sulphureted hydrogen is
passed through the liquid, after it has been acidulated
with dilute hydrochloric acid. The precipitate, after
being washed with solution of carbonate of ammonia till
a yellow precipitate is no longer produced by sulphur-
eted hydrogen, is dissolved off the filter in the small-
est possible quantity of aqua regia. The solution is
now boiled for a while with carbonate of ammonia in
excess, and acidulated and precipitated as before, should
this precipitate be any other color but orange, it is
because of the presence of gold or copper. In this case,
it must be collected on a filter, washed, boiled with
strong water of ammonia, treated with a few bubbles of
sulphureted hydrogen and filtered. To the clear solu-
tion dilute hydrochloric acid must be added, and a stream
of sulphureted hydrogen passed through it, when an
orange precipitate proves the presence of antimony.
That portion of the precipitate which remained undis-
solved in sulphide of ammonium is now examined by
heating it to boiling with dilute nitric acid, after having
ANALYSIS OF COPPER ORES. 97
first thoroughly washed it. The solution may contain
the oxides of lead, bismuth, cadmium and copper. It is
evaporated to a small bulk, mixed with dilute sulphuric
acid, allowed to stand for some time and filtered from
any precipitate of sulphate of lead which may have fal-
len. The solution is now mixed with ammonia till the
liquid smells strongly of it. Should a precipitate fall,
it is bismuth. This may be proved by dissolving the
precipitate in dilute nitric acid, adding a little hydro-
chloric acid, evaporating to dryness, re-dissolving in a
little water, very slightly acidulated with hydrochloric
acid, and then adding much water, when a milkiness
indicates the presence of the last named metal. The
solution, filtered from the precipitate of bismuth, is now
to be acidulated slightly with dilute hydrochloric acid,
and saturated with sulphureted hydrogen. The result-
ing precipitate must be thoroughly and rapidly washed,
and then boiled in dilute sulphuric acid. The resulting
solution is quickly filtered from the insoluble matter,
when, if cadmium be present, it may be known by the
yellow precipitate which sulphureted hydrogen throws
down from the clear filtrate. The copper remains on
the filter as a sulphide, and may be recognized by the
tests already given.
We now return to solution No. II., which is evapora-
ted till it no longer smells of sulphureted hydrogen,
mixed with concentrated nitric acid, and evaporated to
dryness on a sand bath. The residue is digested with
hydrochloric acid on a sand bath until it is white. The
solution is filtered from the insoluble silica ; chloride of
ammonium is added, then strong solution of ammonia,
98 ANALYSIS OF COPPER, ORES.
and lastly sulphide of ammonium, and the whole is
boiled and filtered. The precipitate is thoroughly
washed and heated with dilute hydrochloric acid.
Should a residue remain insoluble, it probably contains
cobalt or nickel. The whole is now to be boiled with
nitric acid, diluted with water, filtered, mixed with ex-
cess of potassa, boiled and filtered.
The precipitate, after being well washed, is dissolved
in warm, dilute hydrochloric acid, mixed with chloride
of ammonium and excess of ammonia, and rapidly
filtered. Before this is done, a portion of the precipi-
tate should be dried, and fused, before the blowpipe, on
platinum foil with nitre and carbonate of soda. A green
color indicates Manganese. The fused mass is dissolved
in water, the solution acidified with acetic acid, and
mixed with a solution of acetate of lead, when a yellow
precipitate will prove the presence of chronium. The
precipitate from the last addition of ammonia is dissol-
ved in dilute hydrochloric acid, and tested with ferro-
cyanide of potassium. A blue color is characteristic of
Iron. The ammoniacal solution is acidified by hydrochlo-
ric acid, mixed with excess of carbonate of ammonia and
boiled. If a precipitate fall, it is probably Manganese,
and may be tested, as already mentioned, by the blow-
pipe.
If any cobalt and nickel be present, they are con-
tained in the solution, which is to be mixed with solution
of cyanide of potassium as long as any change of color
is observed ; then treated with excess of hydrochloric
acid and boiled till no more fumes of hydrocyanic acid
are given off. Potassa is now added in excess, and the
ANALYSIS OF COPPER ORES. 99
solution is boiled till no more ammonia escapes. The
precipitate is probably oxide of nickel, which must be
tested before the blowpipe. The solution is now acidu-
lated with nitric acid, evaporated to dryness, the residue
fused for some minutes, allowed to cool, and then heated
with water. Should a black substance remain, it is well
washed, dried, and fused in the blowpipe flame with
potassa. A blue color indicates cobalt.
The colored residue from solution No. II. is now
mixed with about four times its weight of a dried mix-
ture of the carbonates of potassa and soda, and placed in
a porcelain crucible, which is itself enclosed in a Hes-
sian crucible. If it is desired to protect the porcelain
crucible as fully as possible from too sudden changes of
temperature, the Hessian crucible may be filled with
calcined magnesia, which is to be rather tightly packed.
This precaution, however, is not absolutely necessary,
though by furnishing a more equable heat to all parts
of the inner crucible, it diminishes the risk of fracture.
The outer crucible is now covered with a small piece of
brick, which should fit it with tolerable accuracy, the
inner crucible having been closed with its own appro-
priate lid. Thus prepared, the crucible is introduced
into the fire of a forge, or even a common coal stove,
and heated gradually to bright redness. This tempera-
ture is to be maintained for about twenty minutes, when
upon the withdrawal of the crucible, the mixture within
will be found fused to a glass, with a smooth, depressed
surface. Should this not be the case, it is an indication
that the substance has not been sufficiently heated, in
which case it must be returned to the fire, and kept
100 ANALYSIS OF COPPER ORES.
there till it assumes the appearance described, and then
allowed to cool.
The porcelain crucible is now removed, carefully freed
from every adhering particle of magnesia, placed in a
large beaker, and digested with distilled water in a
warm place. As soon as the fused mass is loosened, it
is removed, and its lower surface examined for globules
of metal, which, however, will rarely, if ever, be found,
should the preceding operations have been properly
conducted. The fused mass should be treated first with
nitric and then with hydrochloric acids, and examined
precisely in the manner already described for the ori-
ginal ore.
If it be desired to ascertain the earthy constituents of
the ore, a matter of no little importance to the smelter,
a further series of operations will be necessary. A por-
tion of the solution resulting from the ebullition with
potassa, in solution No. II., is tested for alumina, by
mixing it with excess of ammonia, and heating it, when,
if that earth be present, a white precipitate will fall.
If, after filtering, the clear solution give a white pre-
cipitate with sulphide of ammonium, the ore contains
zinc.
The other earths will be found in the precipitate ob-
tained by the addition of potassa. After dissolving it
in hydrochloric acid, precipitating with chloride of am-
monium and excess of ammonia, the earth, should no
phosphates be present, will be found in the solution.
Should phosphates be present, it will be necessary to
dissolve the precipitate in dilute hydrochloric acid, mix
the solution with acetate of potassa, add sesquichloride
ANALYSIS OF COPPER ORES. 101
of iron till a red color appears, boil and filter. The
phosphoric acid remains with the iron upon the filter,
while the chlorides of the earth pass through, and are
found in the filtrate.
They are easily detected by the following process : If
the solution be colored, it must be mixed with chloride
of ammonium, ammonia, and sulphide of ammonium,
boiled and filtered, care being taken that during the
whole process it smells strongly of the last named
reagent. The clear solution is boiled to expel sulphide
of ammonium, and mixed with excess of carbonate of
ammonia. The white precipitate is collected on a filter,
and the solution treated with phosphate of soda. A
white precipitate indicates magnesia. The precipitate
is dissolved in dilute hydrochloric acid, and divided into
three parts. To the first portion, sulphate of lime in
solution is added. An immediate white precipitate indi-
cates baryta. The second portion is mixed with a satu-
rated solution of sulphate of potassa, and allowed to
stand till the precipitate settles, care being taken to add
enough thoroughly to precipitate all the baryta and
strontia present. The mixture is now filtered, and am-
monia and oxalate of ammonia added to the filtrate. A
white precipitate shows the presence of lime. The third
solution is mixed with excess of hydrofluosilicic acid,
filtered if necessary, evaporated to dryness, and extracted
with water, which must remain a long time in contact
with it. The solution thus obtained is filtered, mixed
with sulphate of lime in solution, and allowed to stand
for some time, when, should a precipitate form, it is in-
dicative of strontia.
9*
102 ANALYSIS OF COPPER ORES.
QUANTITATIVE ANALYSIS.
Copper is commonly estimated in the form of oxide,
and* the agent used to precipitate it from its solutions is
a solution of pure caustic potash. Some precautions
are necessary in order to insure the success of this pro-
cess. The copper solution is boiled in a porcelain or
platinum capsule, and the potash is added during ebul-
lition, till it no longer produces a precipitate. Oxide of
copper falls in the form of a heavy brownish black powder.
Before filtering, it is necessary to dilute the liquor
and boil it, for if it be too concentrated, some hydrated
blue oxide remains suspended in the solution, and is not
precipitated by boiling. The boiling also is essential,
for should potash be added to a solution of copper in
the cold, the precipitate is blue, bulky, and mixed with
alkali, which it is very difficult to wash out. Boiling
will convert this loose hydrate to the dense black pro-
toxide.
In any case, protoxide of copper is very difficult to
wash, but it may be entirely freed from potash by using
hot water. The cleansing is facilitated by filtering in an
atmosphere of steam. This is conveniently done in Nor-
mandy's filtering apparatus,* but any person of common
ingenuity will be able to contrive means of accomplish-
ing this. After complete washing, the precipitate is
thoroughly dried. For this purpose, I am in the habit
of employing an air oven, attached to my stove. It is
made of sheet iron, and fitted in the stove under the
* See Normandy's edition of Rose's Treatise on Chemical Analysis,
vol. ii. p. 33.
ANALYSIS OF COPPER ORES. 103
pipe. It is provided with several sheet iron shelves,
perforated with holes to receive the necks of the funnels.
After drying, the filter is removed from the funnel,
and separated from the precipitate. This is best accom-
plished by placing the platinum crucible in which the
ignition is to be performed, on the central angles of
four quarter sheets of glazed paper, laid together, and
emptying the precipitate into it. Some of the ox-
ide will adhere to the filter ; this is to be removed by
gently rubbing the filter between the fingers, over the
crucible. With all these precautions, some small parti-
cles of the oxide will still adhere to the filter. To avoid
the loss of these, the filter is to be cut up with a sharp
pair of scissors, and dropped into the crucible, or it may
be burned separately upon the cover, or still better,
rolled into a corner, wrapped with a few turns of thin
platinum wire, and burned in the open air. The crucible
is now removed to the centre of one of the pieces of
paper, and the oxide which has been spilled, carefully
tilted into it.
The ignition may be accomplished either over an alco-
hol lamp, over gas flame, or in the furnace. Should
the former be preferred, a Berzelius or Rose lamp
should be selected. The flame at first should be very
low, until the paper has been slowly charred, after
which it is to be gradually raised till the crucible is red
hot, and kept at that till the paper has burned white.
Care must be taken that the white flame of the lamp
does not touch the sides of the crucible, or it will injure
the metal. If the fire be chosen, the crucible must be
placed in a Hessian crucible, lined with magnesia, as
already described.
104 ANALYSIS OF COPPER ORES.
The ignition of the filter will usually reduce a portion
of the oxide to the metallic state ; but this may easily
be oxidized by directing a current of air upon it during
the ignition. Sufficient draft for this purpose may be
obtained by placing in the crucible a piece of platinum
foil in the form of a partition. A still better method is
to allow the whole to cool, to moisten with a few drops
of nitric acid, and then to ignite the second time.
After ignition, the crucible must be weighed as soon
as possible, or it will absorb water from the atmosphere.
It should not be weighed hot, but immediately after
cooling. It is best to cool it under a bell glass, sup-
ported over a dish of concentrated sulphuric acid.
Every 100 parts are equal to 79.83 of metallic cop-
per.
Sometimes the potash does not precipitate all the
copper from its solution, a state of affairs which may be
recognized by the brown discoloration of the liquid pro-
duced by sulphide of ammonium. Again, after pro-
tracted boiling with potash, some protoxide of copper
adheres to the sides of the capsule in which the precipi-
tation has been effected, and cannot be separated by
mechanical means. When this occurs, the adhering
oxide must be dissolved in a little dilute sulphuric acid,
and precipitated as before, water being previously
added. In very dilute solutions, this accident never
happens.
This process can be used in ammoniacal solutions, pro-
vided they be well boiled and rapidly filtered from the
precipitate. If the ammoniacal liquor be allowed to
stand too long upon the precipitate, it will inevitably
ANALYSIS OF COPPER ORES. 105
re-dissolve some of the oxide, and the liquid would be-
come blue. It should be altogether colorless during the
filtration.
Carbonate of potash cannot be substituted for caustic
potash in these determinations, because it leaves in solu-
tion some protoxide of copper, which can only be sepa-
rated by evaporating the liquor to dryness, and igniting
the salt.
The copper may also be determined in the metallic
state by introducing into the solution a perfectly clean,
polished piece of metallic iron. Much objection has
been made to this process, on various grounds, by differ-
ent chemists. It has been said that it is liable to be
contaminated with the carbon and fibrous flakes of iron,
which will vitiate the result, and that in drying it, a
suboxide of copper will be formed, which will exagge-
rate the per centage.
These objections may be of force in the more delicate
determinations of copper, when absolute scientific accu-
racy is required, but as far as the commercial analysis
of ores is concerned, they have no substantial founda-
tion, if proper care be taken. In the first place, rolled
iron should not be employed, or the carbon separated
will be considerable, and the fibrous pieces detached
during the operation, numerous. I am in the habit of
using bright piano wire, which I roll into a spiral coil,
and introduce into the liquid. Secondly, the solution
of copper must be dilute, and decidedly acid. If it be
too concentrated, all the copper will not be precipitated,
and if it be not sufficiently acidulated, an insoluble ba-
sic salt of iron will mix with the copper, and ruin the
106 ANALYSIS OF COPPER ORES.
analysis. Thirdly, the precipitate, after being tho-
roughly washed, must be dried, at a very moderate
heat. Mitchell says it must not be raised above 212.
I have been in the habit of drying my precipitates in
an air oven, at a temperature of about 150 F., and
I have never been troubled with oxidation.* Fourthly,
there must be no free nitric acid in the solution ; and,
lastly, the precipitate must be very thoroughly washed.
Mitchell prefers zinc to iron for these operations, but
I am of different opinion. I have frequently used the
zinc, and have always been disappointed. It throws
down the copper in a pasty state, from which the zinc
salt is not easily separated, and which, owing to its ex-
tremely minute division, oxidates rapidly, during drying.
Mitchell's reason for preferring the zinc, is the sup-
posed contamination of the precipitated copper by the
separated carbon and detached fibres of the iron. This,
however, depends entirely upon the kind of iron opera-
ted with, and the acidity of the solution. If bar iron
or cut nails be used, the operator will have trouble
enough from this source ; but should he employ good
clean piano wire, he will not be able to estimate or de-
tect the carbon. It is also desirable to use large excess
of iron, as then there will be no risk of annoyance from
little detached filaments of that metal, and if the solu-
tion have been properly acidulated, the copper will
separate in brilliant scales, the under surface of which
* Even if oxidation should take place, the assayer need not reject
his result, and so lose his labor. The error is easily rectified by pla-
cing the whole in a tray of platinum foil, introducing it into a tube of
hard glass, and igniting in a current of washed hydrogen gas.
ANALYSIS OP COPPER ORES. 107
coming off from the iron, will be clean and polished.
If, however, bar iron have been employed, or too much
acid used, the under surface of the copper is frequently
black with carbon, and roughened by detached fibres of
iron. Under such circumstances, it is needless to say
that the process cannot be relied upon, for though the
iron may be separated by dilute hydrochloric acid,
some loss of copper will probably ensue, and the carbon
cannot be got rid of. If the solution be only slightly
acidulated, a sort of galvanic action sometimes takes place
between the iron and the first particles of copper precipi-
tated, so that the copper is deposited in a firm sheet, and
sometimes is so closely adherent to the positive metal as
to be inseparable from it by mechanical means. If, on
the other hand, the solution be too strongly acid, there
is more danger from contamination from carbon.
The time taken up by this process varies with the
temperature at which it is conducted. If the precipita-
tion takes place at the common temperature of the air,
it will require from twelve to twenty-four hours for its
completion. The heat of a sand bath accelerates the
deposition of the copper, and if the solution be made to
boil, all the copper is thrown down in an hour. The
operator usually determines the end of his process by
the solution becoming colorless, or assuming a scarcely
perceptible beryl green hue. A better plan, however,
is to introduce a piece of clean polished iron into the
solution. If, after some minutes, it remain uncolored,
the copper may be considered precipitated.
Levol suggested a method of estimating the quantity
of copper in a solution containing it, which is employed
108 ANALYSIS OF COPPER ORES.
by many chemists. After getting the nitric or nitro-
muriatic solution, he supersaturates with ammonia, and
pours it into a flask or bottle, which can be closed air-
tight with a ground glass stopper, or in any other way.
Cork must not be used for this purpose, as its porous
nature allows air to traverse it, and so vitiates the re-
sult. Some operators close the mouth of the vessel by
tying a bit of sheet India rubber over it, so as thoroughly
to exclude the air. Should the ammoniacal liquor fail to
fill the bottle, water, from which all atmospheric air has
been excluded by recent boiling, is introduced till the
vessel employed is completely filled. A clean, bright
blade of pure copper, which has been carefully weighed,
is now introduced into the whole length of the vessel,
which is immediately closed. The whole is set aside
till the liquor becomes colorless, in consequence of the
formation of a suboxide of copper by the action of the
metal upon the protoxide in solution. The blade is then
quickly withdrawn, washed in distilled water, dried, and
weighed. The loss sustained by the blade indicates the
amount of metallic copper present, for CuO+Cu=Cu 2 0.
One equivalent of copper has abandoned the blade and
formed a suboxide.
I have never been able to get good results from this
process. It is, in the first place, extremely tedious.
Its author says it is finished in four days, but I have
had bottles standing on my shelves for two weeks in hot
summer weather, and still remaining blue. Some che-
mists say that the process can be greatly hastened, so
as to be completed in an hour or two, by closing the
mouth of the vessel with sheet caoutchouc, and heating
ANALYSIS OF COPPER ORES. 109
in a water bath. This method is manifestly inapplicable
in the presence of silver, and other metals, soluble in
ammonia and precipitable by metallic copper.
Cassaseca proposed a method which can only be re-
garded as a rough approximative estimation. He com-
pares the tint of an amrnoniacal solution of the sub-
stance under examination with that of another
ammoniacal liquid containing a known weight of pure
copper.
Copper is also precipitated as sulphide by sulphuret-
ed hydrogen, or by an alkaline sulphide. It cannot,
however be weighed as a sulphide, because in drying,
and even during washing, it absorbs oxygen from the
air. For this reason, it is dissolved in aqua regia or
nitric acid, and precipitated as oxide.
Pelouze contrived a volumetrical process for estima-
ting this metal. It consists in precipitating the copper
from its ammoniacal solution by means of a standard
solution of sulphide of sodium. This salt, the colorless
crystallized hydrosulphate of commerce, is dissolved in
distilled water, and introduced into a graduated tube or
burette, divided into tenths of cubic centimetres. To
determine the value of this standard solution, it is neces-
sary to dissolve a certain quantity of pure copper,* say
a gramme, in pure nitric acid, and supersaturate it
with ammonia until a perfectly clear blue solution
be obtained. This is raised to the boiling point, and
the test solution dropped into it. The copper is pre-
cipitated as sulphide, and the liquor gradually fades.
* That obtained by the electrotype process is generally preferred.
10
110 ANALYSIS OF COPPER OKES.
Dilute water of ammonia is added from time to time, to
replace that which is lost by evaporation, and towards
the close of the operation, the solution is let fall from
the burette, in single drops, the flask containing the
copper salt having been shaken repeatedly during the
operation. As soon as the solution is completely deco-
lorized, the number of degrees is read off from the
burette, and recorded, for the sake of comparison.
The substance to be examined is now dissolved in
aqua regia, treated with ammonia, and decolorized, pre-
cisely in the same manner as the solution of pure copper.
The decrease in the blue color indicates the progress of
the precipitation, and as the period of complete decolo-
ration approaches, it is desirable to add the test solution
in drops, or even to employ the same solution more
largely diluted with a known quantity of water. The
number of degrees must be read off as soon as the
decoloration is accomplished, because the precipitated
sulphide is soon oxidated to sulphate, which is again
dissolved in the ammonia, rendering it blue, so that the
operator, who delays too long, will go on re-precipitating
the same copper, and getting, of course, too large a
per centage.
A comparison of the two readings of the burette will
give the proportion of copper in the substance analyzed.
Thus, if 500 measures of the test solution decolorize an
ammoniacal liquor containing one gramme of pure copper,
and the liquid under examination require 480 measures
to discharge its color, it follows that it contains f $ or
0.96 of a gramme.
This method, according to the author, is liable to
ANALYSIS OF COPPER ORES. Ill
error of not more than five or six thousandths. It is
not interfered with hy the presence of tin, zinc,
cadmium, lead, antimony, iron, arsenic, or bismuth, as
the copper always falls before these other metals. In-
deed, it has been asserted that when the sulphurets of
zinc, cadmium, tin, lead, antimony, and bismuth, are
placed in contact with an ammoniacal solution of sul-
phate of copper, they decolorize it, which proves that
they cannot exist, except for a moment, in a solution
of copper. Iron should be peroxodized before the addi-
tion of the ammonia, by ebullition with nitric acid,
unless the solution should have been made in aqua re-
gia.* It need not be filtered, some chemists say; but
it is a slovenly way of working to decolorize a solution
with a large magma diffused through it. Should there
be a large quantity of iron present, the solution must
be filtered, or it will be impossible accurately to deter-
mine the moment of decoloration, and in all instances
it is best to filter. The other sulphurets go down after
the copper. If zinc alone be present, a white precipi-
tate falls ; if cadmium, a brilliant yellow one goes down
immediately after the decoloration has been effected by
the precipitation of all the copper.
This method is of course inapplicable in the presence
of cobalt, nickel, and mercury, and also when silver is
mixed with the copper. The latter metal, however,
can easily be separated by hydrochloric acid and filtra-
tion, before the ammoniacal solution is made.
It is necessary, in all cases, to estimate the strength
* This is a matter of great importance, for should any of the iron
remain in the form of protoxide, it will vitiate the result, that oxide
being, to a certain extent, soluble in ammonia.
112 ANALYSIS OF COPPEE ORES.
of the standard solution of sulphide of sodium, before
each series of analyses, for this substance is slowly oxi-
dated by exposure to the air, and consequently becomes
weaker as it grows older.
SEPARATION OF OXIDE OF COPPER FROM OXIDE OF BISMUTH.
The agent commonly employed in separating copper
from bismuth is carbonate of ammonia, which when
added in excess, dissolves the copper and throws down
the bismuth. After the precipitation, it should not be
immediately filtered, but should be allowed to stand for
some time in a warm place, to enable the oxide of
bismuth completely to subside. The latter oxide is to
be well washed on the filter with carbonate of ammonia.
The filtrate is now evaporated at a gentle heat, to expel
the excess of carbonate of ammonia, treated with ammo-
nia and precipitated, as already described, by caustic
potash. The oxide of bismuth is ignited and weighed.
This method is not unexceptionable, it being difficult to
separate the last traces of copper from the bismuth.
Cyanide of potassium has been used for this purpose.
A slight excess of carbonate of ammonia having been
added to the solution of the two oxides, it is heated with
cyanide of potassium. Carbonate of bismuth falls, and
the copper remains in solution. The mixture is filtered,
the filtrate evaporated with sulphuric acid, to expel the
hydrocyanic acid,* and the copper precipitated by caus-
tic potash.
* This operation should always be performed under a hood, in a
strong draught, as the fumes of the hydrocyanic acid are a deadly
poison. If the operator has no hood, he should work in the open
air, or with his back towards a strong draught.
ANALYSIS OF COPPER ORES. 113
Another method is to precipitate the two metals as
sulphides, and having well washed and weighed the
mixed sulphides, to introduce them into a glass tube,
connected at one end with an apparatus for generating
chlorine, and at the other, by means of a bent tube dip-
ping under the surface, with a vessel containing water
acidulated with hydrochloric acid. A stream of chlorine
being passed, the sulphides are heated by a spirit lamp,
first gently, and afterwards to redness. The sulphides
are thus converted to chlorides. The chloride of bis-
muth, being volatile, distils over and is dissolved in the
acidulated water, while the fixed chloride of copper
remains in the tube. It is to be washed out with a little
dilute nitric acid, evaporated with sulphuric acid, and
estimated as before.
If the substance treated be an alloy, it may be directly
acted upon by the chlorine.
SEPARATION OF PROTOXIDE OF COPPER FROM PROTOXIDE
OF LEAD.
Copper is often separated from lead by boiling the
solution of the mixed oxides with one of caustic potash.
The process is an imperfect one, leaving always some
lead mixed with the copper.
Carbonate of ammonia has been employed for the
same purpose. The solution is mixed with excess of
this reagent, carbonate of lead is precipitated, and
copper remains in solution. A portion of the copper,
however, goes down with the carbonate of lead, giving a
greenish hue to that salt, which, when pure, is of a clear,
brilliant white.
10*
114 ANALYSIS OF COPPER ORES.
Sulphuric acid is the agent commonly employed for
this purpose. Into the concentrated solution dilute
sulphuric acid is poured as long as a precipitate falls ;
alcohol is then added. The precipitate is collected on a
filter, and washed, first with dilute sulphuric acid, and
then with alcohol. Sometimes, after the precipitation,
the whole is evaporated to dryness, and the mass heated
to expel excess of sulphuric acid. This is thrown upon
a filter, well washed, dried, and ignited, and the copper
is subsequently precipitated with potash. If the alco-
hol have been used, it is necessary first to evaporate the
copper solution, so as to expel this volatile liquid before
precipitating with potash.
A little lead may escape, as the sulphate of this metal
is not altogether insoluble in water. This, however,
will always be found, if the process has been carefully
conducted, in the filtrate from the precipitated oxide of
copper, and may be precipitated as oxalate by oxalate
of ammonia, after having previously neutralized the
solution with a little dilute acid.
Cyanide of potassium is used for separating lead, in
the same manner as already described for bismuth.
Copper has also been separated from lead by using
hydrochloric acid, and precipitating the last traces of
chloride of lead with a strong alcohol. The rest of the
process is conducted as before described, when speaking
of the management of the sulphuric acid process with
alcohol.
SEPARATION OF OXIDE OF SILVER FROM OXIDE OF COPPER.
Silver is easily separated from a solution of the mixed
oxides in nitric acid by the addition of hydrochloric acid.
ANALYSIS OF COPPER ORES. 115
The chloride of silver is collected on a filter, washed by
a continuous stream of water, dried, and fused in a
porcelain crucible. The copper is precipitated from the
filtrate by potash.
Or the solution of metals may be treated with cyanide
of potassium till the precipitate first formed is entirely
re-dissolved, the solution having previously been neutral-
ized with potassa. On the addition of pure nitric acid
to the clear solution, all the silver is thrown down as
cyanide. The filtrate is evaporated with sulphuric acid,
to expel hydrocyanic acid, and the copper precipitated
as oxide by potassa.
Fresenius uses this reagent somewhat differently.
Having obtained the cyanide solution, he passes through
it a stream of sulphureted hydrogen, which throws
down silver only, provided enough cyanide of potassium
be present. The solution is filtered from the sulphuret
of silver, heated to expel sulphureted hydrogen, treated
again with cyanide of potassium, evaporated with a
mixture of sulphuric and nitric acids, and precipitated
with potassa.
SEPARATION OP COPPER FROM MERCURY. -
"When the mixed oxides are dry, they are easily sepa-
rated by ignition, the mercury volatilizing, and leaving
the copper. When in solution, the mixed oxides may
be treated with cyanide of potassium, in the manner
already described for silver. Sulphureted hydrogen,
passed through this solution, throws down the mercury
alone.
Formiate of soda is another agent which has been
116 ANALYSIS OF COPPER ORES.
employed for the separation of these oxides. To the solu-
tion containing the oxide of mercury, (if it is a suboxide,
it must be converted into the oxide by boiling with nitric
acid,) hydrochloric acid is added, and then potassa
nearly to neutralization. Formiate of soda is added,
and the whole is digested for several days at a tempera-
ture of from 90 to 108, care being taken that the
temperature last named be not exceeded. The mercury
falls as a subchloride, which is to be collected upon a
weighed filter. As some mercury may escape, the
filtrate is treated in the same manner as the original
solution, allowed to stand for twenty-four hours, and
any precipitate which may fall, added to that already
on the filter. The chloride is dried at a very gentle
heat, and weighed. The copper is precipitated, as
oxide, from the filtered liquor, by hydrate of potash.
SEPARATION OF OXIDE OF COPPER FROM OXIDE OF CAD-
MIUM.
Carbonate of ammonia in excess is added to the solu-
tion ; carbonate of cadmium and oxide of copper, with
a little oxide of cadmium, remains in solution. If this
solution be exposed to the air, the oxide of cadmium is
all deposited, and oxide of copper alone remains in solu-
tion, which is precipitated as before.
Cyanide of potassium may be employed by adding
this reagent till a clear solution be obtained. Sulphu-
reted hydrogen is passed through the mixture, sulphuret
of copper remains in solution, and sulphuret of cadmium
falls. The solution is boiled, to expel excess of sul-
phureted hydrogen, some cyanide added, and the hy-
ANALYSIS OF COPPER ORES. 117
drocjanic acid driven off by evaporation with sulphuric
acid, or by boiling with hydrochloric acid, nitric acid
being added from time to time, as long as any hydrocy-
anic acid is given off. The copper is then pre'cipitated
as oxide.
SEPARATION OF OXIDE OF COPPER FROM THE OXIDES OF
URANIUM, NICKEL, COBALT, ZINC, IRON, AND MANGA-
NESE, AND FROM THE EARTHS AND ALKALIES.
The method usually adopted for the separation of
oxide of copper from the above named oxides, the sul-
phurets of which are soluble in dilute acids, is to preci-
pitate as sulphuret by a stream of sulphureted hydrogen
passed through an acid solution.
Some precautions must be observed in order to secure
satisfactory results. In the first place, if the solution
be, as it generally is, a nitro-muriatic one, it must be
evaporated with repeated additions of hydrochloric acid,
to expel free nitric acid, for if any of the latter solvent
remain, it will act upon the recently precipitated sul-
phuret of copper.
The sulphureted hydrogen must be passed till no
further precipitate falls, and till the solution smells
strongly of this reagent. The precipitate must be
rapidly filtered, and washed uninterruptedly, because if
it remain any length of time exposed to the air, it ab-
sorbs oxygen, and is partly converted into 'sulphate of
copper, which passes through the filter, and turns the
filtrate brown, in consequence of a re-precipitation of
the sulphate of copper by means of the sulphureted
hydrogen it still holds in solution. It is advisable,
118 ANALYSIS OF COPPER ORES.
indeed, to wash it with water charged with sulphureted
hydrogen, which decomposes the sulphate on the filter
as fast as it is formed. During the whole process the
solution " and precipitate should smell strongly of this
gas.
Various methods have been adopted for the disposal
of this sulphide. It cannot be weighed as sulphide,
because a portion of it must be oxydated in drying. It
is, therefore, to be converted into oxide. To effect this,
some roast it in a platinum or porcelain crucible, first at a
low red heat, then at a little higher temperature, finally
raising the whole to whiteness, to expel the last trace of
sulphuric acid. This method cannot be trusted, because
we can never be sure that there is not some undecom-
posed basic sulphate left behind, nor that some suboxide
has not been formed during the process. It is, there-
fore, advisable to dissolve it in some hot aqua regia, and
precipitate the oxide of copper with hydrate of potash.
Some chemists, after having thoroughly washed the
sulphide of copper, introduce a clean beaker under the
funnel, perforate the bottom of the filter, and wash down
the sulphide with distilled water. The precipitate is
then treated as before with aqua regia.
Others allow the precipitate to dry till it can be easily
separated from the filter. It is then detached, and
treated again with aqua regia. The filter, which re-
tains a little sulphide, is burned, and its ash, dissolved
in aqua regia, added to the solution of the precipitated.
The whole is then filtered and precipitated.
It is a bad plan to digest the filter with the precipi-
tate in nitric acid or aqua regia, because the action of
ANALYSIS OF COPPER ORES. 119
the nitric acid on the paper, generates an organic com-
pound which materially interferes with the precipitation
by solution of potash. When this has heen done inad-
vertently, the solution is to be evaporated to dryness
with sulphuric acid in slight excess, the resulting sul-
phate of copper dissolved in water and precipitated with
potash.
It should be remarked that this process, though com-
monly adopted, is not applicable when zinc and nickel
are present, because appreciable quantities of these me-
tals always go down along with the copper. To meet
this difficulty, M. Flajolot has indicated a method of ac-
complishing this by means of hyposulphite of soda, or of
sulphurous acid solution of iodine.
The former reagent is employed in the following
manner : The solution must contain neither hydrochlo-
ric nor nitric acid, both of which are expelled by evapo-
ration with sulphuric acid. Water is then added, and a
solution of hyposulphite of soda poured into the solution
of the mixed oxides, kept at the boiling point, till it no
longer produces a black precipitate. The complete
precipitation is known by the subsidence of the subsul-
phide of copper and the absence of suspended sulphur
in the supernatant liquor. This precipitate is collected
on a filter, washed with boiling water, and treated as
already described, to convert it into oxide of copper.
The zinc, nickel, or cobalt, is precipitated with carbo-
nate of soda from the nitrate from the subsulphide of
copper.
By this method copper may be separated from all
those metals which are not precipitated from their acid
solutions by sulphureted hydrogen.
120 ANALYSIS OF COPPER ORES.
The second process is conducted as follows : The sub-
stance containing the copper is dissolved in nitric acid,
the solution evaporated so as to drive off the greater
part of the excess of acids ; water is then added, and if
antimony be present, tartaric acid. Should a residue
remain after digestion, it is filtered, and to the clear
solution are added, first, sulphurous acid, and then
iodine dissolved in sulphurous acid. This last must be
poured in in small portions, and the operator should
stop as soon as the precipitate ceases to fall. The
liquid should be allowed to stand at least twelve hours
before filtering, and this last operation must be very
cautiously conducted, as the iodide of copper has a ten-
dency to rise and run over the edge of the filter.
The iodide thus obtained may be dried at a steam
heat, and then weighed ; or it may be dissolved in aqua
regia, like sulphide of copper ; or it may be dissolved
in ammonia, exposed to the air some hours, so as com-
pletely to oxidize the product, and filtered ; or, finally,
it may be introduced into a matrass, and dissolved in a
stream of chlorine. In whatever manner the solution
be effected, the copper is precipitated and weighed as
oxide.
Berthier separates oxide of copper from the oxides
under consideration, by boiling the solution with excess
of sulphite of ammonia. Copper alone is precipitated
as a subsulphite.
A very common, but altogether objectionable, method
of separating copper from iron, is to precipitate the iron,
as sesquioxide, with ammonia. Copper remains in solu-
tion, and the whole being thrown on the filter, the
precipitate is thoroughly washed, dried, ignited, and
ANALYSIS OF COPPER ORES. 121
weighed. The copper is then estimated as oxide, in
the manner already described. A notable proportion
of copper is lost by this process, since it goes down
entangled with the iron, and escapes the ammoniacal
solvent. I have repeatedly tried it upon weighed mix-
tures of pure copper and iron, and have invariably got
an excess of the last named metal, in spite of the most
careful washing. In some instances this has amounted
to nearly two per cent.
The process of precipitating the copper, in the metal-
lic state, with iron wire, is quite applicable to its separa-
tion from these metals, since none of them are thrown
down by iron.
Hautefeuille recommends the following process of
separating copper and zinc in the analysis of alloys
of those metals : One gramme of the alloy is treated
with nitric acid, and ammonia added to precipitate
any tin, lead, antimony, or iron, that may be pre-
sent. Acetic acid is now added in excess, and a
sheet of lead suspended in the solution, the whole being
kept boiling for two hours, after which time the liquid
will be colorless, the copper being precipitated as metal
upon the surface of the lead. In adopting this plan,
arsenic must first be got rid of by a known weight of
litharge.
SEPARATION OF GOLD FROM COPPER.
Gold is frequently separated from copper in the dry
way, by cupellation, a process which will presently be
described.
It may be conveniently "separated by sulphate of iron.
11
122 ANALYSIS OF COPPER ORES.
This salt ought to be of a beryl green hue approaching
blue ; should it be yellowish green, it contains oxide of
iron, which somewhat delays the determination of the
precious metal. The solution of aqua regia is repeat-
edly evaporated to dryness with hydrochloric acid, till
all traces of nitric acid have been expelled ; the residue
dissolved in water, and solution of sulphate of iron
added to it so long as a precipitate falls. The solution
of the mixed metals should be kept decidedly acid du-
ring the entire process. Gold is precipitated, and cop-
per remains in solution.
Oxalic acid may be added to the acid hydrochloric
solution of the mixed metals, the same precautions being
observed in regard to the expulsion of nitric acid. A
slow evolution of carbonic acid takes place ; gold is pre-
cipitated, and copper remains in solution.
Or, the acid solution may be just neutralized with
soda or potash, and sulphurous acid being added, the
whole is boiled, the gold being precipitated and the cop-
per remaining in solution.
SEPARATION OF COPPER FROM ANTIMONY, ARSENIC, TIN,
PLATINUM, GOLD, IRIDIUM, TELLURIUM, TUNGSTEN,
VANADIUM, AND MOLYBDENUM.
The sulphides of the metals above enumerated, being
all soluble in alkaline sulphides, a simple process suffices
to separate them from copper. The solution having
been carefully neutralized, is precipitated with sul-
phide of potassium. The metals above named all
remain in solution, while sulphide of copper goes down
mixed with the sulphides of metals the separation of
which from copper we have already studied.
ANALYSIS OF COPPER ORES. 123
The common method is to precipitate the copper from
the acid solution with sulphureted hydrogen, and then
to boil the mixed sulphides with yellow sulphide of
ammonia, as already described under the head of Quali-
tative Analysis. The objection to this process is, that
sulphide of copper not being entirely soluble in sulphide
of ammonia, some of that metal is lost.
We shall make a few remarks on this subject under
the next head.
ASSAY OF COPPER.
The term assay is applied both to the dry and the
wet method of determining the quantity of metal in an
ore or an alloy. The classification of ores, however, is
generally based upon the convenience of the dry assay.
For this purpose, copper compounds are classified as
ores and alloys. The ores are distributed under three
heads.
I. Substances which are entirely free from sulphur,
selenium, and arsenic, and contain no other metal but
iron.
II. Substances which contain sulphur or selenium,
but no foreign metal but iron.
III. Sulphides which contain various metals.
For the performance of the dry assay, certain arti-
cles of laboratory furniture are indispensable. The
operator should have a good wind furnace. One four-
teen inches square by twenty-four deep, with a chimney
thirty feet high, will give heat enough for an iron assay.
A very good size for a copper furnace is nine inches
square by sixteen deep. This will give a sufficient
124 ANALYSIS OF COPPER ORES.
body of coal for ordinary purposes. It is well enough
to have another furnace of the same length and breadth,
but only six or eight inches deep, .with the flue opening
as near as possible the top. An iron plate covers the
furnace, forming a sort of table over the flues, and the
upper openings are closed by sliding plates. The flue
ought to have a chimney to regulate the draught.
When these conveniences are not to be had, a copper
assay can be made in a cylinder anthracite stove, pro-
vided it has a strong draught, or even in a smith's forge.
In the latter case, however, great care must be taken to
avoid too high a heat.
The operator must, of course, have suitable tongs,
pokers, &c., with iron rods flattened at the end, for the
purpose of stirring the roasting ore. The crucibles
employed may be either the common Hessian or the
French of Beaufaye, which last are more durable, though
this is a matter of no great consequence in a copper
assay.
He must also be provided with finely powdered lime,
kept in a well-stopped bottle ; carbonate of soda, which
has been dried by heating to low redness, also kept in
the same way ; fine powder of charcoal ; dried borax
and black flux. The latter is easily prepared by mixing
two parts of argol, the crude tartar of commerce, with
one of nitre, and igniting them with a red hot iron rod.
Some other reagents in the dry way are used, which
will be mentioned further on ; but those just named are
sufficient for most purposes.
The best fuel for the purposes of the assayer is coke.
The firmest pieces are selected and broken into pieces
ANALYSIS OF COPPER ORES. 125
about the size of small egg coal. It is well to have two
sizes of broken fuel, one large, for the general heat,
and another smaller, for fitting around the crucible. If
the fuel be too small, the draught will be obstructed ; if it
be too large, it will be difficult to arrange it properly
around the crucible. Charcoal or anthracite may be
used if the operator cannot get coke ; but the first is
troublesome, because it burns out so rapidly that it
requires constant replenishing, and the latter is annoy-
ing, on account of its propensity to split and fly.
Bituminous coal is dirty and smoky, and its swelling
interferes with the operation. The crucible is some-
times placed in a hollow in the fire, but more commonly
it rests on a support of fire-brick, placed on the grate
bars, and the fire is built up around it.*
ASSAY OF SUBSTANCES OF THE FIRST CLASS.
When the ores or slags of this class are tolerably
rich, the assay is simple and easy. The substance is .
reduced to a fine uniform powder, by rubbing it up in a
mortar, and passing it through a sieve. Should there
be much metallic copper present, it will be very difficult
to pulverize it, as it will flatten out in little sheets
under the pestle. In this case, it is customary to sepa-
rate these strips, and estimate the copper in them sepa-
rately. It is then a simple calculation to apportion the
per centage. If, however, the assay is to be made of
the entire mass powdered, they must be thrown in.
The fine powder is now to be mixed with three times
* For further information on this subject, see my work on Dental
Chemistry and Metallurgy.
11*
126 ANALYSIS OF COPPER ORES.
its weight of black flux, in a porcelain mortar, and
poured into a crucible. The mortar is then to be
rinsed out with black flux, which is to be added to the
mixture already in the crucible, and then covered with
a thin layer of the same flux, unmixed with ore. As
the fusion of these ingredients will cause the mass to
swell and bubble, care must be taken to select a cru-
cible so large that it will be only half filled with the
mixture.
The whole is then introduced into a furnace, which
has been previously heated. The heat is gradually
raised to bright redness. At this point, the mass be-
comes pasty, and begins to rise and fall, little puffs of
vapor breaking through the imperfectly fused materials.
Each jet of vapor burns with a violet flame, showing
the combustion of the reduced and volatilized potassium
of the black flux. When a mixture of carbonate of
soda and powdered charcoal is substituted for this re-
agent, the flames are yellow. In about fifteen or twenty
minutes the bubbling ceases, and the contents of the
crucible sink down in tranquil fusion to the bottom of
the pot. The surface of the flux is smooth, and marked
with lines radiating from the centre to the circumfe-
rence. An earthen cover is now put upon the crucible,
and the heat is pushed nearly to whiteness, and kept at
that for about ten minutes. At the end of that time
it is withdrawn, and tapped gently on some hard sub-
stance, to cause the small globules of molten metal
diffused through the slag to settle to the bottom. If
the fusion has been carried far enough, the slag will
have a smooth, shining surface, depressed in the centre.
ANALYSIS OF COPPER ORES. 127
When the crucible is cold enough, it is broken, and the
copper extracted.
If the operation has been successful, the button of
copper has a clean, polished surface, and does not ad-
here to the crucible. Should it be marked by little
depressions, it is an indication that the heat has been
too high, and that some copper has been volatilized.
The quality of the metal is tested by hammering it out
upon a smooth anvil. If it is soft, yields easily, and
flattens down without breaking at the edges, it is com-
monly regarded as pure copper, for iron usually renders
it brittle. This is, however, by no means a universally
reliable test. There are alloys of iron and copper
which are malleable, and I have seen an assay button,
containing 33 per cent, of iron, flatten out unexception-
ably under the hammer. The proper plan, therefore,
is to dissolve the button in aqua regia, and test for
iron.
The quantity of ore to be employed for this purpose,
varies with its richness. Of average ores, 200 grains
are sufficient ; while for poorer ores, 400 grains should
be taken.
It sometimes happens that these ores of the first class
are contaminated with some sulphur, in which case the
copper button will be surrounded by a steel-gray invest-
ment of sulphide of copper. When this is the case, the
ore must be treated in the manner presently to be de-
scribed, under the head of Ores of the Second Class.
Slags are commonly assayed in this manner ; but
when they are poor, containing only two or three per
cent, of metal, all the copper is not readily obtained,
128 ANALYSIS OF COPPER ORES.
since the viscidity of the slag retains some of it, and
other portions of it enter into chemical combinations
with the various ingredients. Under these circumstan-
ces, it will be well to dissolve the slag, if soluble, in
acids, and estimate the capper by the methods already
described. It often happens, however, that slag is a
definite silicate which will not dissolve in acid. In
these cases, a moderate quantity 100 or 200 grains
is fused in a platinum or smooth porcelain crucible with
twice its weight of dry carbonate of soda. The whole
crucible is introduced into a beaker, containing distilled
water, and digested at a moderate heat till the softened
mass swells and separates readily from the crucible. It
is then treated with aqua regia, in a flask or matrass,
the solution transferred to a porcelain capsule, evapora-
ted to dryness, moistened with hydrochloric acid, re-
dissolved in water, and the copper estimated in the
manner already described.
If, however, it be desired to determine it in the dry
way, the substance may be fused at the high heat of an
iron assay, the operation being considerably prolonged.
When the crucible is removed and broken, a button,
containing a large amount of iron, will be found. This
is to be analyzed, as already described, in the humid
way.
A better plan than this, is to sulphurate the poor slag
or ore, as the globules of sulphuret are larger than
those of metallic copper, and fall more readily through
the melted slag. The metal is then obtained in the
form of a flattened button of sulphide, the further assay
of which is conducted as shall be described in the next
ANALYSIS OF COPPER ORES. 129
section. This process, though tedious, yields better
results than any other dry process for poor ores.
ASSAY OF SUBSTANCES OF THE SECOND CLASS.
Ores of this class contain sulphur, and sometimes
selenium, are generally sulphides or sulphates, and
are assayed either for regulus or matt, or for cop-
per.
SULPHATES. With a reducing flux, the sulphates
yield copper and a slag containing a double sulphide of
copper and the alkaline metal of the flux. The more
of the latter is employed, the less metal and the more
sulphureted slag is obtained ; but if it be only used in
sufficient quantity to reduce the copper, the metal sub-
sides pure, and a slag remains containing only sul-
phate.
" Thus, it has been ascertained that the neutral anhy-
drous sulphate of copper gives, firstly, 27 per cent, of
copper, with three parts of black flux, (about two-thirds
only of that which it contains,) and a black crystalline
slag, containing much sulphur. Secondly, with two
parts of the same flux, 37 per cent, of copper and a
clean gray slag, containing very little sulphur. When
but one part of black flux is employed, there is not a
sufficiency of carbon to reduce the whole of the oxide,
and only about 12 or 14 per cent, of metallic copper is
produced, which is enveloped in a red, vitreous, opaque
slag, composed of protoxide of copper and alkali, and
above which is a layer of fused sulphate of potash,
which is crystalline and colorless.
130 ANALYSIS OF COPPER ORES.
" It may thus be seen that in order to extract the
whole of the copper from a sulphate in this manner,
that the proportion of reducing flux which will give
the maximum result, and which will also produce a slag
containing but little sulphur, must be arrived at by
guess-work.
" The sulphates of copper, however, are completely
decomposed by heat ; and the easiest and best method
of assaying them, is to expose them to a white heat in
a platinum crucible till nothing more is given off. The
residue is oxide, which can be fused with three parts of
black flux, when all the copper contained in it is exactly
and readily separated in the metallic state.
" The compounds of oxide of copper with sulphuric
acid may be assayed by fusion in an earthen crucible
with from one to two parts of carbonate of soda ; the
fused matter must be poured into an ingot-mould, pul-
verized, and re-fused in the same crucible, after mixture
with its own weight of black flux. By fusion with car-
bonate of soda, the sulphate of copper is decomposed,
and sulphate of soda and a compound of the oxide of
copper and alkali formed, which is afterwards com-
pletely reduced by black flux, without the possibility of
the formation of a sulphuret of copper."*
The sulphates of copper, however, being soluble in
water, are more easily analyzed by the humid process.
The substance is dissolved in hot water, filtered, well
washed, acidulated with hydrochloric acid, and the cop-
per precipitated from it by metallic iron.
* Mitchell's Manual of Assaying.
ANALYSIS OF COPPER ORES. 131
SULPHIDES. Fusion for Regulus or Matt. This is
a simple process, and easily performed by the merest tyro.
All that is necessary is to mix the ore with its own
weight of glass of borax, to introduce it into a crucible,
and heat it to full redness. The gangue or vein-stone
enters readily into fusion with the borax, and the sul-
phide or regulus subsides. Care must be taken in
separating this from the crucible, as it is exceedingly
brittle, and apt to stick to the sides and bottom. To
obviate this, Berthier lined his crucibles with charcoal,
which allows the button to be readily detached, when the
crucible is broken. Phillips recommends the use of a
common crucible, but pours the whole fused mass into
an iron mould, of an elliptical form, from which the
regulus is easily separated, by turning the mould over
when cold, and giving it a few taps upon some hard
body.
During this process, some sulphur is sublimed, whence
it happens that the regulus contains less sulphur than
the ore. It is manifest, therefore, that the proportion
of vein-stone cannot be determined from the loss expe-
rienced in this fusion.
If the operator wishes to imitate the furnace processes,
by using the fluxes employed in smelting on a large scale,
such as quartz, baryta, lime, &c., the crucible must be
lined and the heat that of an iron assay.
Assay for Copper. In order to estimate copper in
the dry way in this class of ores, it is necessary first to
roast them so thoroughly as to expel every trace of sul-
phur. In order to accomplish this, it is necessary first
to reduce the ore to the finest possible powder, to intro-
132 ANALYSIS OF COPPER ORES.
duce it into a crucible, and place the whole in a furnace,
which should be at a low red heat. The crucible is laid
slanting in the fire, the damper closed, and" the ore stir-
red assiduously with an iron rod, so as continually to
expose fresh surfaces to the air. It is essential that at
this period the heat should be low, test the sulphuret
should fuse or at least agglutinate, a circumstance
which would necessarily interfere with the oxydation.
Blue flames of sulphur will be seen to play over the sur-
face of the roasting mass, but they gradually give place
to white fumes of sulphurous acid. These, in their turn,
disappear, and the heat is slowly raised, the ore being
constantly stirred. The operator, from time to time,
holds a glass rod moistened with ammonia, over the cru-
cible, to determine by the fumes, whether sulphurous
acid continues to be given off. The heat is pushed now
and then to full redness, which expels the sulphurous
acid formed by the mutual reaction of the sulphides and
sulphates. When the fumes on the rod dipped in am-
monia are no longer visible, the heat is raised to white-
ness in order to decompose the sulphates by driving off
their sulphuric acid.
Mitchell objects to this process of roasting as ineffi-
cient, since some of the sulphates remain undecomposed
even at this elevated temperature. To meet this diffi-
culty, he proposes to stir in with the roasting ore, at
full redness, some carbonate of ammonia in small por-
tions, so that a double decomposition may take place,
and the sulphuric acid be all driven off as sulphate of am-
monia. In practice, however, this process is objectiona-
ble. It matters not how cautiously the carbonate of
ANALYSIS OF COPPER ORES. 133
ammonia be added, it is dispersed with a kind of explo-
sion which inevitably causes a loss of some of the finely
powdered ore. When the crucible is allowed to cool be-
fore the addition of this volatile salt, and then reheated,
this objection does not hold. Mitchell pulverized his
carbonate of ammonia and added it in the proportion of
one-tenth the entire amount of ore.* If, however, the
assayer take care to heat the ore to whiteness, he may
be certain that all the sulphuric acid will be expelled.
The reduction of the roasted ore is commonly effected
by mixing it with three or four times its weight of black
flux, introducing it into the same crucible in which the
roasting was effected, covering it with about half an inch
of glass of borax, and heating it in a wind furnace for
about twenty minutes, in the manner described under the
last head.
If the gangue be silicious and aluminous, the fusion
is facilitated by the addition of lime to the flux, on the
well-known general principle that a mixture of several
earths is more fusible than a single one. If the usual
quantity of ore (200 grains,) has been selected for an
assay, it may be thoroughly mixed in a mortar with 50
grains of lime, 300 of dry carbonate of soda (i. e. car-
bonate of soda, recently heated to redness,) and from 20
to 40 grains of charcoal, according to the richness of
the ore. Some assayers make it into a paste with oil
and pack it in the crucible. The whole is now intro-
duced into the fire and kept at a dull red heat for about
fifteen minutes, or until the mass has ceased to swell
* Should the arsenic be present, it is advisable to mix the ore with
charcoal. Some make it into a paste with sawdust and oil.
12
134 ANALYSIS OF COPPER ORES.
and bubble. It is then covered with an earthen lid and
heated to a full red approaching whiteness, for about the
same length of time. It is not absolutely necessary to
cover the crucible, but it is better to do so, as some bits
of coal may get in, and cause a loss of copper which
may adhere to their rough, irregular surface.
The crucible having cooled, is broken and the metallic
button removed. Any adhering particles of slag are
easily removed by a few gentle taps of the hammer.
The surface of the button is now examined. If it is
clean and bright, it may be inferred that the operation
has been properly conducted. If, however, it be envel-
oped in a coating of gray brittle regulus, the assayer
may know that his roasting has been imperfectly per-
formed and that all the sulphur has not been expelled.
The whole operation must then be repeated. It is al-
ways advisable to prepare two crucibles in the same man-
ner, and to carry on the operation upon two samples of
ore at the same time.
Various processes have been suggested, in order to
avoid the trouble and delay of roasting. Mr. Maughan
suggested an ignition in oxygen. He placed the sub-
stance in a porcelain tray which was introduced into a
tube heated to redness, while a stream of oxygen gas
was passed over it. The roasting was in this manner
very rapidly accomplished, but the difficulty of decom-
posing the sulphates was not overcome.
" With nitre all the copper can be extracted, (from
the sulphuret,) but with difficulty, and finding by repeat-
ed experiments, the quantity which produces the maxi-
mum result. Sulphuret of copper fused with a mixture
ANALYSIS OF COPPER ORES. 135
of an alkaline carbonate and metallic iron, allows a cer-
tain quantity of copper to be set free ; but this quan-
tity never surpasses three-fourths of that contained.
This maximum is obtained by using four parts of car-
bonate of soda, and thirty or forty per cent, of iron fil-
ings. The slag is black and homogenous.
" Copper pyrites is decomposed by the alkaline car-
bonates, but without the production of metallic copper.
A black crystalline homogeneous slag is formed, which
contains an alkaline sulphuret, a sulphuret of iron, sul-
phuret of copper and oxide of iron.
" With black flux a very fluid homogeneous crystal-
line slag is produced, the color of which is black with a
metallic lustre, and in which not the smallest trace of
metallic copper can be distinguished. The result is the
same as the addition of iron, which is perfectly inert,
and remains disseminated in the slag.
" Copper pyrites is readily attacked by nitre, and
either copper or sulphuret of copper can be separated
from it by means of this reagent. But in order to ar-
rive at this result, it is necessary to guess the quantity
of nitre ; so that it is evidently not a good method of
assay.
" It is necessary, in order that the slag be fluid, to
add a little borax or an alkaline carbonate ; so that the
reduced metal may collect into one button. With one
part of nitre, two of carbonate of soda and one of bo-
rax, pure copper pyrites gives from 36 to 46 per cent,
of sulphuret ; with double that quantity of nitre it gives
thirty per cent, of metallic copper."
The above account of the behaviour of sulphureted
136 ANALYSIS OF COPPER ORES.
copper ores, with different reagents, taken from Mitch-
ell's Manual, throws light upon the various processes
adopted. The success of the nitre assay depends upon
its oxydating the sulphur in the mixed sulphides of the
ore, forming sulphuric acid which combines with the
potash. If the exact quantity of nitre, necessary for
this oxydation, be hit upon, the maximum quantity of
metallic copper is obtained.
Mr. Lewis Thompson has suggested a nitre process by
which he proposes to get rid of the guesswork of the
common fusion with nitre. He heats the finely powder-
ed ore in a crucible to redness, and throws upon it ex-
cess of nitre. Powdered charcoal is then added so long
as any deflagration takes place, and the heat is pushed
to bright redness for a quarter of an hour.
The process is an imperfect one, on account of the
continued presence of the sulphur. I have repeatedly
tried it with all possible care, but have never been able
to obtain satisfactory results. Two crucibles placed side
by side in the same fire, and treated as nearly as possible
in the same manner, have often given me different quan-
tities of copper with this process.
It occurred to me to try cyanide of potassium as a
desulphurating agent, since it is so efficient in reductions
before the blow-pipe. My plan was to fuse a small quan-
tity of cyanide in the crucible and when it was liquid,
to add to it the finely powdered ore. A pasty mass re-
sulted which when heated to redness swelled a good deal.
Some more cyanide was then thrown in, as long as effer-
vescence took place, and glass of borax placed on top.
The heat was then pushed and the rest of the process
ANALYSIS OF COPPER ORES. 137
conducted as before. I have obtained very good results
in this way, but often, without apparent cause, I have
failed.
At this point, I may remark that the dry assay can-
not be relied on as giving a satisfactory determination
of the copper contained in the ore, because, no matter
how carefully the process may have been conducted, we
can never be certain that the button contains copper
only. It is valuable, however, as an indication of the
manner in which the ore will behave in the furnaces, the
proportionate yield of metal which may be expected, the
nature of the slag, and a variety of similar matters
which will readily occur to the mind of the practical man.
Sulphureted ores are commonly dissolved in aqua re-
gia, as already described. Mr. Lewis Thompson uses
chlorate of potash instead of nitric acid as an oxydizing
agent. He pours upon 100 grains of the finely powder-
ed ore concentrated hydrochloric acid, adds chlorate of
potash in small portions, stirring all the while with a
glass rod, until all action ceases. Should the residue be
white, the operation may be regarded as completed ;
should it still remain dark, it is placed upon a sand-bath,
and heated, additions of chlorate of potash being made
from time to time, till all action has ceased. Should
the residue still continue dark, it is to be roasted, and
then treated in the same way again. The resulting so-
lutions are mixed and precipitated with metallic iron.
It is necessary to conduct this operation under a hood,
with a strong draught, or dangerous results may follow
from the stifling vapors of euchloine which are abundant-
ly evolved.
12*
138 ANALYSIS OF COPPER ORES.
Rivot's process may be adopted, when zinc in the form
of sulphide, is not present. The ore having been re-
duced to an impalpable powder, (by porphyrization, if
necessary,) is warmed with an alkaline liquor, and a
stream of chlorine gas is passed through the whole. The
copper and the other metals remain at the bottom as
oxides, and the sulphur, arsenic and antimony are con-
verted into acids which combine with the alkali to form
salts.
The dry process above described may be performed
directly upon the ores themselves when they are rich,
but when they contain only 8 or 10 per cent., it is bet-
ter to run them down first as regulus and then apply the
process of roasting and fusion to that. If there is much
earthy matter present, it interferes with the roasting,
both by shielding portions of the ore from the oxydating
influence of the air, and by furnishing bases with which
the sulphur and newly formed sulphuric acid may com-
bine. In the subsequent fusion also, they have a ten-
dency to stiffen the slag and prevent the descent of the
globules of metal. It is, therefore, better in these cases
to adopt the fusion for regulus, as that enables us to ob-
tain all the metal free from gangue, and the resulting
sulphide can then be treated like a rich ore.
ASSAY OF ORES OF THE THIRD CLASS.
Ores of this kind require roasting, but it must be con-
ducted with more care than the same process employed
upon a simple sulphide, because they are far more fusi-
ble than the substances belonging to the last class. The
metal obtained from the calcined ore requires a further
ANALYSIS OF COPPER ORES. 139
operation, to be described under the next head, because
it is a true alloy.
When the ore contains lead, especial care is necessary
in roasting, as it so greatly increases the fusibility, that
it is extremely difficult to expel all the arsenic and sul-
phur, without agglutinating the mass. It is better, in-
deed, in all cases, to obtain a regulus first and roast that,
as the loss of sulphur and arsenic, during the process of
fusion, renders the subsequent roasting more easy, by
rendering the matt less fusible.
In an arsenide of copper, the first results of roast-
ing are volatilization of a portion of arsenic and the for-
mation of oxide and arseniate of copper and metallic
copper. The arseniates and arsenides react on each
other at a high heat, and arsenious acid is formed and
vaporized. After the whole of the arsenide has been
decomposed, there still remains behind some arsenic, in
the form of arseniate of copper, which cannot be vola-
tilized at a roasting heat. This is decomposed by add-
ing finely powdered charcoal and heating to bright red-
ness. The arseniates are reduced with the formation of
arsenious acid which is expelled. In spite, however, of
all this care, some arsenic will contaminate the button
obtained in the subsequent fusion.
ASSAY OF SUBSTANCES OF THE FOURTH CLASS.
Alloys containing more oxydizable metals than copper
are purified by a process called refining, which is in
reality, a cupellation performed on copper.
For this purpose the operator must have a cupelling
or assay furnace, with a strong draught, some cupels
and tongs of a suitable construction. The furnace
140 ANALYSIS OF COPPER ORES.
should have a strong draught, and be provided with a
muffle in which the substance in the cupels is to be heat-
ed. The cupels are made of bone ash, and resemble
little saucers with a flat bottom. For fuller information
on the construction and management of the furnace and
cupels, the reader is referred to the author's work on
Dental Chemistry and Metallurgy.
The cupel having been introduced into the muffle and
the whole being brought to a red heat, the button of
copper is dropped into the cupel from a pair of tongs,
when the muffle is closed to exclude the air and raise the
temperature to the fusion point of copper. After the
melting of the button, the muffle door is opened, and a
little pure lead added to the alloy. Oxydation of the
lead and the combined metals now begins ; the button is
agitated with a rapid rotary motion, and covered with
an iridescent pellicle of oxide, which continually flows
off and is absorbed by the cupel. When the process
is about to terminate, the motion becomes more rapid
and the colors of the pellicle brighten, till the button
becomes suddenly solid, when the coating disappears en-
tirely and the movement of the button ceases. This is
called brightening or fulguration.
The cupel is now immediately removed. The button
is covered with a fine crust of protoxide of copper which
is not easily detached if allowed to cool slowly, but
plunged while still hot into water, the oxide can be
beaten off with a hammer. It is usually recommended
to cover the button with about 7 per cent, of its weight
of pure fused borax, finely powdered. The berate of
copper thus formed, is very brittle and only slightly ad-
herent to the metal, being easily detached by a single
ANALYSIS OF COPPER ORES. 141
blow of the hammer. If the red hot button be plunged
into a weak solution of phosphate of soda, the same re-
sults follow. The purity of the metal is known by its
fine red color and its malleability.
It must be observed, however, that this method is not
rigorously exact, because some copper is oxydated and
sinks into the cupel along with the lead and other me-
tals, and another portion is removed with the coating of
oxide or borate of copper taken off from the refined
button.
It is manifest, furthermore, that two cases may occur ;
the copper alloy may not contain lead, or it may be
mixed with that metal. In the first case, a tenth part
of lead is added till the copper be pure. To determine
the true per centage of copper, Berthier recommends
that one-eleventh of the weight of all the oxydizable me-
tals including the lead added, and one-tenth of the
weight of the borax thrown on the hot button should be
added to that of the. assay button obtained. It is man-
ifest, that however near this estimate may be to the
truth, and however well it may answer for practical pur-
poses, it has no claim to be considered scientifically ex-
act, because the loss depends not only upon the nature
of the oxydizable metals present, but also upon the heat
to which the button has been subjected.
In the second case, or when the copper alloy contains
lead, that metal may exist in three different conditions ;
there may be either too little for the purposes of the re-
finer, or just enough, or too much. When there is too
little, lead must be added by tenths till the button is
pure. When there is just enough, there is of course,
nothing to be done but to proceed with the cupellation.
142 ANALYSIS OF COPPER ORES.
When there is too much, a weighed quantity of pure
copper must be added, and the usual allowances made in
estimating the button.
This process may be conducted without the inconveni-
ence of these numerous suppositions, by operating at
once upon two samfples, one of pure copper, the other of
the alloy to be examined. For this purpose, two cupels
are placed side by side in the same muffle, and when
heated sufficiently, 4 parts of pure lead are introduced
into each. As soon as the metal is melted, 1 part of
pure copper is introduced into one, and 1 part of the
alloy under examination into the other.
The refining is conducted in the usual manner, and
when the resulting buttons are weighed, it will be found
that that obtained from the pure copper is the heavier.
By adding the loss of the fine copper to the weight of
the button refined from the alloy, the quantity of pure
copper contained in the last is determined, since we
have every reason to suppose that the loss of copper in
both assays is precisely the same.
In operating upon cupriferous leads, 1 part of pure
copper is treated with 4 parts of pure lead in the cupel,
and with 4 parts of the cupriferous lead in the other.
The second operation gives more copper than the former,
and the difference is the proportion of copper in the cu-
priferous lead.
The advantage of this method is that it furnishes good
data whereupon to compute the probable result of me-
tallurgic operations in such alloys, on the great scale.
The process is, however, not applicable to alloys con-
taining much zinc or tin. Indeed, in all cases, the hu-
mid analysis furnishes by far the most exact results.
CHAPTER III.
MINES AND MINING.
IT is necessary, in order to understand the character
of mineral deposits, to have some distinct ideas of the
general principles of geology. We shall, therefore, re-
call to our readers' recollection a few of the simpler
facts of that science, before proceeding to give an ac-
count of mines or mining operations.
The earth, upon which we live, is generally believed
to be a mass of fused matter which has cooled off upon
the surface. The centre is supposed to be still in a state
of igneous fusion,* while the cooled surface forms a crust
upon which all the substances which maintain our pre-
sent existence are found. To this crust the observations
of geologists have been confined, and they have been
able to lay down certain definite laws for the guidance
* There are many phenomena which support this opinion, and
which, indeed, seem inexplicable upon any other theory. Thus, in
mines and artesian wells, it has been observed that a depth is soon
reached, which the ordinary surface changes of temperature no longer
affect, and that, as we descend, we find a heat continually increasing.
This increase is found to be one degree of Fahrenheit's thermometer for
every 55 J feet, so that at less than 1-700 of the earth's radius a tem-
perature of 3600 will be obtained. At 1-50 of the distance from the
centre, therefore, we may conclude that every thing is in a state of
fusion.
144 MINES AND MINING.
of practical men, which are as positive as any other
rules deduced from the study of nature.
The most superficial knowledge is sufficient to deter-
mine the fact that this crust, of which we have been
speaking, is not a homogeneous mass, but is composed of
quite a variety of substances commonly known as mine-
rals. These are found in various positions and in vari-
ous degrees of aggregation, and to their masses geolo-
gists have applied the generic term, rock.
Every one must have noticed that some rocks split up
readily into layers, while others only afford irregular
masses when broken, and that the former lie in regular
strata superimposed upon one another, while the latter
present no indication of such an arrangement. The for-
mer are called stratified, the latter non-stratified or crys-
talline rocks. The latter pi-esenting all the appearances
of having cooled from a state of fusion, have received
the additional name of Plutonian or igneous rocks, while
the former, resembling the deposits now taking place
from turbid water, are called also Neptunian or sedi-
mentary rocks. When these have come in direct con-
tact with the igneous rocks, still fluid, the heat of the
fused mass has produced a change in the character of the
sedimentary rock, and without destroying its stratifica-
tion has rendered it crystalline. The deposits thus al-
tered have received the name of metamorphic rocks.
If the earth had never been subject to violent convul-
sions, we might imagine the layers of these sedimentary
and metamorphic rocks surrounding it in segments of
concentric spheres, like the coats of an onion. But in
reality, the surface has been disturbed both before and
MINES AND MINING. 145
after the deposition of these rocks. We have, therefore,
numerous irregularities in the position of the layers.
Great masses of crystalline rock, during those terrible
convulsions which characterized the early ages of the
world, have been thrown violently up from the fused
centre, upheaving the superficial strata. Sometimes
this upheaval seems to have been in the form of a great
wave, rolling under a wide area, so that half a conti-
nent has been lifted up without greatly disturbing its
surface. At others, the melted matter has been forced
up in a single circumscribed jet ; has burst through the
crust turning up its layers, and protruding above in high
hills or mountain masses. The traveler, therefore, as he
passes over the broken edges, in approaching the centre
of upheaval, goes over them in the order of succession
from above downward, but after crossing the ridge, finds
them arranged in the reverse order. Now it is evident,
that if water should have swept over these displaced
strata, with great violence, it would have removed the
surface, and worn them irregularly, in accordance with
their relative hardness, forming hills and valleys of de-
nudation. Again, should a sea have rolled for any time
over the upturned edges of the broken rocks, stratifica-
tion would again have taken place, and as this would
necessarily form an angle with the original direction of
the layers, we would have what is called unconformable
stratification. These may again be worn by water, and
in the new hollows, still later deposits may occur, so that
it would be easy to make gross errors in regard to the
age of rocks, if we had not some guide to show us the
order of the deposits. We find an index of this in a
13
146 MINES AND MINING.
careful study of the succession of the strata, but chiefly
in the fossils which the different formations contain.
In the foregoing remarks we have spoken in accord-
ance with prevailing geological opinions, to which it is
well now to give a more formal expression. In the cool-
ing of the crust of the earth, we take it for granted that
there must have been much contraction. This contrac-
tion must of course compress the central fluid, and be-
ing unequally acted on, it must break out at the point of
least resistance. Other causes besides this contraction,
may act to produce the occasional escape of the central
liquid. Through the rents, however made, fused matter
may be extruded, and in this manner, many have ac-
counted for the existence of metallic veins, and for the
greater certainty of continued value in the regular
veins. This, however, is a subject to which we shall
presently recur.
The first geological division of rocks was into prima-
ry or primitive and secondary. The term primitive or
primary was applied indiscriminately to all crystalline
rocks, while secondary was the title of all the stratified
rocks. The facts of the science, however, began soon
to accumulate so rapidly, that they could no longer be
crowded into such narrow limits. The secondary rocks
were, therefore, divided into transition, secondary and
tertiary. The first of these terms was applied to the
lower stratified rocks, which, though sedimentary, never-
theless, contain abundance of crystalline minerals. The
more recent deposits were called tertiary, and everything
between the two retained the old name of secondary.
The term primary is now used very loosely, some writers
MINES AND MINING. 147
confining it strictly to azoic rocks, or those without orga-
nic remains, while others extend it to the palseozoic series,
or those in which we find the earliest traces of organiz-
ed forms. Indeed, this whole system of nomenclature
is gradually passing away, but as it is still partially em-
ployed we shall presently give a table of it. It will
first, however, be necessary to explain briefly the terms
applied to the principal varieties of rock. Those who
wish more minute information, must have recourse to
works on mineralogy and geology.
Granite is a mixture of feldspar, quartz and mica, in
varying proportions. When studded with crystals of
feldspar, it is called porphyritic granite. If hornblende
takes the place of mica, the resulting rock is sienite.
Porphyry is a mass of feldspar containing crystals of
the same mineral.
G-neiss is only a stratified granite, resulting from the
uniform direction of the mica.
Trachytes are the products of old volcanos, which
have sometimes flowed out as lava, and sometimes have
merely formed a pasty mass. Like porphyry, they are
composed of a feldspar base and often contain imbedded
crystals of that mineral.
Basalt is the eruption of more recent volcanos than
those which give rise to trachyte. It has a tendency to
separate into hexagonal prisms of great size, composed
of segments fitting into one another by means of a
rounded head adapted to a saucer-like depression. Mine-
ralogically, it consists of feldspar and augite, and often
contains distinct crystals of one or both of these min-
erals.
Trap or greenstone is a dark, heavy rock, containing
148 MINES AND MINING.
feldspar and hornblende, and is either crystalline or com-
pact.
Lavas are the eruptions of modern volcanos, and are
usually formed in their strata on the sides of the moun-
tains whence they have issued.
Schists or schistose minerals are those which split easily
in their layers.
Sand is a term usually applied to loose particles of
quartz. Should they be agglutinated by a cement, the
resulting rock is a sandstone.
Calcareous rocks are composed of carbonate of lime,
mixed sometimes with carbonate of magnesia. In the
-latter case, the rock is called dolomite. Marble, Iceland
spar, chalk and limestone are the common species of this
class of rocks.
The table we have selected is that of Sir H. T. De la
Beche, which shows the order of succession of the strata
of Western Europe.
UPPER STRATIFIED, OR FOSSILIFEROUS ROCK.
I. TERTIARY, OR CAINOZOIC.
II. SECONDARY, OR MESOZOIC.
III. PRIMARY, OR PALEOZOIC.
I. Tertiary, or Cainozoic.
(a. Mineral accumulations of the present time.
b. Pleistocene.*
c. Pleiocene.
B. Middle Tertiary, Miocene.
C. Lower Tertiary, Eocene.
* These terms are combinations of Greek comparatives and super-
latives, with a word denoting recent. Thus Pleistocene indicates those
layers which have the greatest number of recent species. Pleiocene
those which have more than the strata below them, Miocene, those
which have fewer, and Eocene (dawn of recent,) those in which the
existing types just begin to show themselves.
MINES AND MINING.
149
A. Cretaceous
Group,
B. Marine equivs
lents of
C. Jurassic or
Oolitic Group,
D. Triassic Group, -
II. Secondary, or Mesozoic.
a. Chalk of Maestricht and Denmark.
b. Ordinary chalk, with and without flints.
c. Meerschaum beds, or upper green sand.
d. Gault.
e. Shanklin sands, vecten, neocomian, or lower
green sand.
a. Wealden clay, ~| Organic remains in these
b. Hastings sands, j- are of a fluviatile, lacus-
c. Purbeck series, J trine or estuary character;
a. Portland oolite or limestone.
c. Portland sands
d. Kimmeridge clay.
e. Coral rag and its accompanying grits.
/. Oxford clay, with Kelloway's rock.
g. Cornbrash.
h. Forest marble and Bath oolite.
i. Fuller's earth, clay and limestone.
k. Inferior oolite and its sands.
I. Lias, upper and lower, with its intermediate
marlstone.
a. Variegated marls, Marnes Irishes, Keuper.
b. Muschelkalk.
c. Red sandstone, Grds Bigarr, Bunter sand-
stein.
III. PKIMARY on PALAEOZOIC.
(a. Zechstein, dolomitic, or magnesian limestone.
b. Rothe todte liegende, lower new red conglo-
merate and sandstone, gres rouge.
B. Marine equiva- f a. Coal measures, terrain Houiller, Stein Koh-
lents of \ len Gebirge.
(a. Carboniferous and mountain limestone, with
its coal, sandstone, and shale beds, in
some districts. Calcaire carbonize.
Berg kalk.
[_ b. Carboniferous slates and yellow sandstone.
D. Devonian group. { Various modifications of the Old Red Sandstone
. Upper: Ludlow rocks, Wenlock shale and
,, Q limestone, Woolhope limestone.
)U P- 1 ft. Middl: Caradoc sandstone and conglomerate.
Llandeilo and Bala beds.
13*
f a. Upper
I li
1 b. Middle
[ c. Lower :
150
MINES AND MINING.
F. Cambrian group.
Barmouth sandstones, Penrhyn slates, &c.
Various rocks subjacent to the Silurian se-
ries in Wales and Ireland, and above the
mica and chlorite slates, quartz, and other
rocks of Anglesea and part of Caernarvon-
shire. Unknown : probably primitive.
MINERAL VEINS.
The metallic products of the earth are found in a
great variety of situations. These have been classified
under the following heads :
I. SUPERFICIAL OR ALLUVIAL.
a. Constituting the mass of a bed or stratified
deposit.
II. STRATIFIED. -i b. Disseminated through sedimentary rocks.
c. Originally deposited from aqueous solution,
but since metamorphosed.
a. Masses of eruptive origin.
b. Disseminated in eruptive rocks.
c. Stockwerke deposits. Irregular
III. UNSTRATIFIED d. Contact deposits.
MINERAL VEINS. ] e. Fahlbands.
/. Segregated veins.
g. Gash veins. Regular.
h. True or fissure veins.
I. Superficial or Alluvial Deposits. All the
alluvium that we have upon the surface of the earth is
the result of the wearing away of older formations. If
a mass of rock, subjected to the wasting action of the
water, frost, and atmospheric influences, should contain
metallic substances, we must expect to find them mixed
up with the sand and gravel which are formed from its
ruins. These alluvial districts are often of great extent,
and though the working of them cannot be properly
called mining, they furnish large amounts of the most
valuable metals. Most of the gold, much of the tin,
MINES AND MINING. 151
and all the platinum of commerce, comes from such
workings.
The position of these different metals varies considera-
bly. The alluvial gold is usually found at all depths of
the soil in which it occurs. Tin, on the contrary, gene-
rally lies below the surface, and is covered in by a
greater or less depth of gravel, sand, or clay, and some-
times peat. In order to get at the tin gravel, it is
necessary first to remove this overlying earth, when the
metalliferous pebbles will be found, generally lying upon
the primitive rock.
The amount yielded by these washings is very great.
Every one knows that the majority of the gold in Cali-
fornia, comes from the surface washings. All the Austra-
lian, and nearly all the Russian gold, so far, has been
produced in that way. When we know that California,
in 1853, produced 250,000 pounds troy of the precious
metal, Australia 210,000, and Russia 64,000, we see
the immense value of these superficial deposits. Of
platina, during her period of greatest mining activity,
Russia produced nearly five thousand pounds annually.
Of tin, Banca alone produces from her alluvial deposits,
5,000 tons a year.
Stratified Beds. Under this head are included all
metallic deposits which have evidently been formed at
the same time with the sedimentary rocks in which they
occur. The best illustration of this method of occur-
rence of metalliferous beds is to be found in the seams
of iron ore interstratified with the coal in this country
and in Great Britain. When the more valuable metals
are found in such layers, the deposits are usually
152 MINES AND MINING.
regarded with suspicion.' They rarely increase in rich-
ness as they descend, and they cannot be expected to
"hold out" sufficiently to justify any large investment
for their development. There are exceptions to this
rule, however, as we shall see, when we come to speak
of the Mansfield schists.
Unstratified Deposits. Under this head, we find
the most valuable collections of metallic ores. They
are divided in our tables under two heads, regular and
irregular deposits.
IRREGULAR DEPOSITS. 1. Eruptive Masses. These are
aggregations of rock resembling the surrounding non-
metalliferous rocks. The ores which most frequently
occur in this manner are the oxides of iron, which seem
to have been thrown up at the same time with the igne-
ous rocks in which they are found. The great iron-
ridges of the West are good examples of this form of
metallic deposit. They either form ridges, parallel with
those of the neighboring strata, or assume the form of
rounded masses, which have evidently burst up from
below, fracturing the crust upon the surface, and fusing
or otherwise changing the strata in immediate contact
with them.
2. Disseminated in eruptive rocks. It often happens
that in a great upheaval of trap, we find numerous me-
tallic particles, widely diffused through the entire mass
of rocks. In this manner platina sometimes occurs.
Magnetic iron is found in such abundance diffused
through the trap at Tabey, in Sweden, that it can be
worked to advantage. At Geyer, in Saxony, small
thread-like veins, and minute particles of tin, are
diffused through a great mass of granite.
MINES AND MINING.
FIG. 1.*
153
STOCKWERKE.
3. Stockwerke. A stockwerk is a series of small
veins intersecting one another and ramifying through a
mass of rock, which often contains also minute particles
disseminated through it. The name has been given to
them because they are worked in different stages or sto-
reys, one above another. For the same reason, the
English call them floors. Tin occurs in this manner,
both in Cornwall and in Saxony.
FIG. 2.
CONTACT DEPOSIT.
a Deposit of ore between two formations.
4. Contact Deposits. These metalliferous beds are
formed, as their name implies, at the point of contact of
two formations dissimilar in their geological and mine-
ralogical character. When a mass of eruptive rock,
(trap, for example,) breaks through another formation,
* This and the following illustrations are taken from Whitney's
" Metallic Wealth of the United States."
154 MINES AND MINING.
modifying its mineral contents, a line of ore will often
be found separating the two kinds of rock. If not
exactly upon the dividing line, it occurs at no great
distance from it, and preserves a general parallelism
with it. Or metalliferous minerals may be found lying
between two successive overflows of igneous rock, or
diffused through both of them in the neighborhood of
the separating surface. Thus, the iron ores of the
Hartz follow the contact-planes of the trap and the
uplifted slates ; and those of the Vosges surround a
central nucleus of porphyry, and line all the cavities of
the fracture produced by the upheaval. The copper
ores of Monte Catini, in Tuscany, are developed along
the line of outcrop of the gabbro, a rock resulting from
the metamorphic action of serpentine upon the cretace-
ous strata.
5. Fahlbands. These are best developed in Norway,
at the silver mines of Kongsberg.* There, in the crys-
talline states, occur parallel belts of rock of very con-
siderable length and breadth, impregnated with the
sulphurets of iron, copper, and zinc, with a little lead
and silver. These are disseminated through the rock
in such minute portions as to be hardly visible, and
only to be recognized by their tendency to decompose,
and thus to give the rock a rotten appearance. To this
they owe the name "fahlband," or "rotten belt," the
word fahl being a corruption of faul, the miners term
for a rotten rock.
These belts at Kongsberg exhibit the general charac-
* They have been traced for several miles. The greatest breadth
of any one of them is a thousand feet.
MINES AND MINING. 155
ter of the rest of the strata in the vicinity, having the
same direction and inclination, and being, like them,
schistose. The quantity of metallic matter contained
in them is generally small, and rarely pays for working.
They are, however, traversed by true veins, containing
silver ores, and these are only productive where they
pass through the fahlband. The chief mining value,
therefore, of these strata, results from their enriching
influence on the true veins which intersect them. Even
with these, the mining here is very expensive.
Deposits of the kind we have just been describing,
under these five heads, while often developed to such an
extent as to be valuable, are generally inferior to true
veins. They are not so deep, have gangues which are
hardly to be distinguished from the adjoining rocks, and
often are destitute of any proper vein-stone. As a gene-
ral rule, they cannot be worked to the same advantage
as the regular deposits, since the miner can rarely have
any security that they will hold out sufficiently to justify
the necessary expenditure.
REGULAR DEPOSITS. These are classified under three
different forms, which are not always easily distinguished
from one another. Surface examination is often insuffi-
cient to enable the most experienced observer to decide
whether a true vein exists, and an exploration of some
depth below the surface is absolutely necessary to settle
the question.
Werner defines veins as "mineral repositories of a
flat or tabular shape, which traverse the strata without
regard to stratification, having the appearance of rents
or fissures formed in the rocks, and afterwards filled up
156 MINES AND MINING.
with mineral matter differing more or less from the
rocks themselves." Whitney objects to this definition
as excluding many veins which do not traverse, but run
parallel with the strata, and others which occur in
unstratified rocks. His definition is, *' an aggregation
of mineral matter of indefinite length and breadth, and
comparatively small thickness, differing in character
from, and posterior in formation to, the rocks which
enclose it." Both these definitions include veins which
do not contain metal.
Weissenbach divides true veins into six different classes.
1. Veins of sedimentary origin. If a fissure should
exist in a rock upon which a new deposit of a sediment-
ary character was taking place, it must, of course, be
filled by the sedimentary matter, which will be stratified
in it just as it is on the general surface of the rock.
2. Veins of attrition. These are fissures filled with
matter introduced by purely mechanical means, such as
the falling of fragments of wall rock from above, or friction
of their sides upon one another. Many ore-bearing veins
exhibit phenomena of this kind.
3. Veins of infiltration, or stalactitic veins. These
result from the filling of fissures by incrustation of the
sides with calcareous matter deposited from water, pre-
cisely in the same manner in which stalactites are formed
in caverns.
4. Plutonic veins. These are fissures filled with
mineral matter injected from beneath, or pressed up-
wards while in a plastic state.
5. Segregated veins.
6. Metalliferous veins, proper.
MIXES AND MINING.
157
Before going further in the description of true veins,
we pause to explain certain technical terms in common
use among miners. Veins, as we have already said,
may be barren of metal ; hence, the word vein is a
generic term. Those which contain ores are called
lodes, and those which are not productive, and are not
in the usual direction of the lodes of a district, are
termed cross courses. The rock in which the lode is
found is called the country. The dip or inclination of the
vein towards the horizon, is its hade, slope, or underlie,
and its superficial length is its run, bearing, or direc-
tion. Strings are small filaments into which the vein
splits, and these, when very small, are called threads.
The two sides of the cavity, which contain the lode, are
called iv alls ; and if the vein has a considerable inclina-
tion, its upper boundary is called the hanging wall, and
its lower, the foot wall.
We now resume the consideration of the classes of
regular deposits.
Fio.
SEGREGATED VEINS.
a Segregated mass of ore cropping out at the surface. 6 Parallel layer not extend-
ing upward so far.
14
158
MINES AND MINING.
1. Segregated veins. These are veins which have a
crystalline structure, or a gangue differing from the
adjacent rocks, but which do not appear to occupy a
previously existing fissure. They seem to have been
gradually separated by chemical action from the sur-
rounding formation ; hence their name, segregated
veins. They differ from true veins in their relation to
the adjacent stratification. They lie parallel with the
cleavage of the surrounding rocks. The downward
extent varies greatly, and the mass generally thins out,
and entirely disappears at a greater or less distance
from the surface. In the Rammelsberg, one of the
FIG. 4.
SECTION OF THE RAMMELSBERG.
a c Principal mass of ore lying in the direction of the argillaceous shales. 6
Branch four hundred feet deep, dipping further from the perpendicular.
Hartz mountains, a famous mine of this character oc-
curs. The main mass of ore lies in the direction of the
argillaceous slates of which the mountain is composed.
At the depth of about four hundred feet, it sends off a
branch which crosses the dip of the slates at an acute
MINES AND MINING. 159
angle. The greatest thickness of the mass is more than
one hundred and fifty feet, and its length about nine-
teen hundred. As it descends, however, it grows
smaller. Thus, at eight hundred and fifty feet, it has
contracted to twenty feet in thickness and seven hun-
dred and fifty in length. It has no proper vein-stone,
but is a mass of sulphurets of iron, zinc, lead, and
copper, and almost entirely destitute of gangue. The
veins of gold quartz are usually of this character, oc-
curring in belts which dip with the stratification.
These deposits cannot be relied upon as true veins.
They are almost always richest at the surface, and are
liable to thin out, or ^en entirely to disappear. The
ore is distributed through them with no regularity,
occurring usually in nests and pockets, arranged in a
general linear direction, and connected by mere threads
of ore or barren vein-stone.
FIG. 5.
MS
GASH VEINS.
a Upper series of veins, b Stratum cutting off the upper series entirely from c,
the lower series of veins, which are independent fissures.
2. Crash veins. These veins occupy pre-existing
fissures, which are not attended by any considerable
breaking up of the strata. When there is a marked
160 MINES AND MINING.
difference in the character of the rocks which make up
any particular series, the fissures are usually confined
to one member of the series, and disappear on passing
to the next. If the same rock occurs again on the other
side of the interpolated mass, the veins may be found in
it. Lateral branches are often found in connection
with the main fissures, and usually at right angles to
them.
The origin of this class of fissures has been attributed
to the shrinkage of the rocks, either during cooling, or in
consequence of a subsequent exposure to long-continued
heat. Thus, mineral contents may have been deposited
as sediment, or segregated from -the mass of the rock.
They differ from true veins, in not showing such distinct
selvages, and in the less decidedly crystalline character
of their vein-stones. They are generally found in those
sedimentary rocks which have undergone but little
change, and still retain the original lines of stratifica-
tion. They are still less reliable than segregated veins,
but their number often makes up for their limited ex-
tent, so that, while any individual vein cannot be
expected to hold out, the region in which they occur,
may, for a time, furnish a large amount of ore.
3. True veins. These are fissures in the crust of the
earth, of indefinite length and depth, which have been
subsequently filled with mineral matter. As they are
believed to have originated in a fracture of the strata
caused by the action of a powerful force far below, they
may be expected to extend indefinitely downward. Ex-
perience so far verifies this opinion that no well devel-
oped and well defined vein has yet been found termina-
MINES AND MINING. 161
ting entirely at any depth which has been reached, while
nothing is more common than a total disappearance of
the other forms of deposits which we have described.
The length of veins upon the surface varies greatly.
Some have been traced for miles, and differ, as to their
metallic contents, in different parts of their course, some
points being entirely barren, while others are well charged
with ore. As a general rule, the longer the vein, the
more liable is it to prove productive somewhere. Some
of the great veins in Mexico have been followed more than
six miles, and opened and worked in many places. The
length and breadth of a vein have no necessary relation.
The width is of course irregular, because when the frac-
ture took place the rocks were not only torn apart, but
also uplifted, so that one side of the crack has slid upon
the other, making a fissure altogether devoid of paral-
lelism between its two faces. If this notion of the pre-
vious fracturing of the surface be correct, we should
expect to find a concentration of veins in certain
regions of the earth, for a great upheaval which should
fracture the crust in one place, would be likely to cause
numerous cracks all about the centre of the greatest
force. It certainly increases the probability of the cor-
rectness of the theory, to discover, as we do, the very
limited and scattered districts which have so far pro-
duced the metals in general use among men.
The vein is not a mass of ore exclusively. The
greater portion of it is occupied by some rock, different
from the surrounding strata, which is known as the vein-
stone or gangue. Quartz is the most common mineral
found in this position. It occurs in a variety of forms,
14*
162
MINES AND MINING.
usually highly crystalline, especially in the " vugs," or
cavities, of the vein. Each mineral district appears to
have vein-stones peculiar to itself.
b d e f
PART OF A LODE AT WHEEL JULIA, NEAR BIXNER DOWNS, CORNWALL.
a Bisulphnret of copper and sulphuret of zinc. 6 Comb of quartz, c Wall of in-
durated argillaceous matter, d Comb of quartz, e Large comb of quartz, with
blende and copper ores/ on both sides, g Cavity or vug, in another comb of quartz.
h More solid comb of quartz.
The minerals in a well defined lode often form a
series of plates, parallel to the walls of the lode, and
containing crystals set at right angles to them. These
crystalline layers are called combs, and their faces meet
and interlock with one another. Sometimes these are
arranged in perfect symmetry, the same substances
crystallizing with great regularity at corresponding dis-
tances on each side of the central mass.
In addition to the true vein-stones, the lode often
contains fragments of the adjacent strata, which appear
to have been introduced mechanically. These may be
in numerous minute pieces, so as to give the gangue a
brecciated character, or they may be in large masses.
When one of the latter occurs, it is called a " horse,"
and the vein is said to "take ahorse." The fissure
MINES AND MINING.
163
has often numerous offshoots, or supplementary fissures,
branching from it; these are called "droppers," when
they leave the vein, and when they concentrate, or fall
into it again, they are named "feeders." Their direc-
tion and appearance are important guides to the miner.
The vein-fissure is sometimes abruptly contracted, and
then it is said to be "nipped."
FIG. Y.
TRAVERSE SECTION OF A VEIN.
The mass of vein-stone is usually separated from the
wall by thin bands of clay, or similar soft substance,
which are called "selvages." By preventing too close
adhesion to the rock, they facilitate the removal of the
164 MINES AND MINING.
contents of the vein. The walls are often smooth and
grooved as though the lode had rubhed against them.
These surfaces are called "slickensides."
Few veins are so uniformly rich in ore as to pay for
the entire removal of their contents. It is customary,
therefore, to confine the operations to the rich por-
tions of the vein, leaving the poor undisturbed. The
waste, unproductive matter brought to the surface, is
called deads or attle. The rich bunches are very irregu-
lar in their occurrence, and the chances of finding them
in any particular spot can only be estimated after a
thorough examination of the system of lodes in the dis-
trict under consideration. One kind of rock usually is
richer than any other, and this presents, of course, the
greatest inducements for a liberal expenditure of time
and money. Where there are numerous parallel veins,
the run of the courses of ore, or the relation of the rich
masses to the entire vein, will usually be found to be
similar in all the lodes. When, therefore, one has been
properly opened and explored, it serves as a guide to
all the rest. It requires, however, no little experience
to decide upon the characters which justify working,
and even then, the longest acquaintance with these sub-
jects will often serve to mislead the miner who attempts
to apply the rules of one district to another mining
region.
The irregularities of the fissures, of course, involve
the practical miner in numerous difficulties. A vein has
been known to dip parallel with the strata, and then to
be shifted to a plane twenty or thirty feet distance,
without any dislocation of the surrounding rock. In
MINES AND MINING. 165
such a case, a fissure may connect the two fragments of
the vein, and yet be so small as to escape attention.
At Holzappel, in Baden, there is such a shifted vein,
in which the fissure, though cut by a level, was entirely
overlooked, and the lode was not discovered till after a
shaft had been sunk from the level, in the other portion
of the vein. A true vein also may for some distance
coincide with the dip of the strata, and may send out
offshoots which follow the planes of cleavage, and yet
the main fissure in the rest of its course may cut the
different layers across. In such a case, it will be neces-
sary to cut the lode for some distance, in order to ascer-
tain whether it be a genuine fissure-vein, and whether
the branches parallel to the stratification, have not been
opened along the line of easiest fracture.
After the first set of fissures had been made and filled
up, there was no reason why a new set should not occur,
since the crust of the earth was still subject to the same
influence. There is abundant evidence of such subse-
quent fractures, in the numerous secondary veins which
cross the older lodes, and " heave" them to one side or
the other. There are even examples of a tertiary set
of fissures crossing both the former. We have already
said that these veins, when destitute of ore, are called
"cross-courses;" when they contain ore, they receive
the name of " contra-lodes."* Cornwall contains seve-
ral systems of fissures, and it is remarkable that those
of the same age are usually parallel, and contain the
* These crossings of different sets of veins are usually considered
favorable indications of rich veins, especially at the point of con-
tact.
166
MINES AND MINING.
same varieties of ores and veinstones. In the Hartz
there are two principal directions of fracture. In the
Freiberg districts, these intersections are more numer-
a b c d e f g h i k k i
FRAGMENTS OF THE DREI PRINZEN SPAT VEIN. NEAR FREIBERG.
a Blende, b Quartz, c Fluor Spar, d Blende, e Heavy Spar. / Sulphnret of
Iron, g Heavy Spar, h Heavy Spar, i Sulphuret of Iron, k Calcareous Spar.
ous than anywhere else, more than nine hundred differ-
ent veins having been recognized in the space of forty
or fifty square miles.
In this country no such complicated system has yet
been discovered. In the Lake Superior region, the
veins of any limited district are usually parallel. Some
movement of the planes of stratification upon one an-
other has taken place, which has shifted the veins for a
few feet in the direction of the slide.
One of the most commonly received opinions as to
the method in which metallic veins have been formed, is
that which attributes them to the injection of molten
matter from below into the previously formed fissures.
MINES AND MINING. 167
This may be true of a limited number of veins, those
for instance, which have igneous veinstones, but it can-
not be used to explain the production of the majority of
metalliferous lodes. The difference in the value of the
vein in different members of the geological series in
Avhich it occurs, appears to be a formidable objection to
this theory. In the same light, also, must we regard
the usually unbroken condition of the walls of the cav-
ities which contain the lodes.
Another theory accounts for the formation of veins
by sublimation from below and condensation in the fis-
sures. There are facts which accord very well with this
opinion. Thus, at Nagyag, in Transylvania, metallic
arsenic is deposited upon those faces of crystals of
manganese-spar which have been turned downwards.
There are, however, a great number of phenomena which
refuse to adapt themselves to any such notion. The
variation in the character of lodes in different rocks is
as little explicable upon this hypothesis as upon that
last noticed. The presence of non-volatile matter in
veins has also been objected, but it is not easy to de-
cide what is, and what is not volatile, at the high tem-
perature of the earth's centre. The veins to which this
theory is most applicable, are those of mercury.
At present, the views of the advocates of lateral secre-
tion are most generally received. Those who hold these
opinions, believe that the mineral and metalliferous par-
ticles have been separated from the surrounding rocks
in a state of solution, and have been deposited within
the vein by the action of electro-chemical forces. It is
certainly in favor of this theory, that the majority of
168 MINES AND MINING.
the veinstones, such as calcareous spar, quartz, &c., are
now generally believed to have been deposited from
aqueous solution, and certainly cannot have been sub-
limed by igneous action. The ores may also be depos-
ited in the same way. Galena has been made artificial-
ly, in the laboratory of the chemist, from aqueous solu-
tion by double decomposition. Sulphuret of iron is a
common product of the contact of ferruginous waters
with decaying organic matter. Murchison has shown
that the copper ores of the Permian strata, in Russia,
must have been formed in the same way, since they are
accumulated round the remains of the stems and branches
of plants.
The fissures opened deep in the crust of the earth,
may be supposed to have been filled with water holding
mineral matter in solution. Passing through the differ-
ent strata, these solutions would be differently acted
upon in accordance with the varying chemical constitu-
tion of the rocks. If the water were acidulated, it
would act upon the metallic particles with which it came
in contact. It is easy to see how, on this hypothesis, a
vein might be richer in certain rocks than in others.
Either the rock might contain more metallic substances,
or it might act more readily upon those in solution in
vein-fissures. That some action has taken place in the
surrounding strata, is evident from their alteration in
the neighborhood of the lode. They are either decom-
posed and rotten, or they are more impregnated with
silicious matter. In the latter case, the flinty masses
are called by the Cornish miners the capels of the lode.
The existence of electric currents in veins has been
MINES AND MINING. 169
established by the testimony of several independent ob-
servers. They are supposed to originate in the lode and
to have no connection with the great magnetic circles of
the earth.
Nearly all veins are characterized near their surface
by evidences of atmospheric or other chemical action.
The surface ores vary from those which we find below,
in being far more highly oxydized. Thus, if the mass
of the vein contain sulphurets, we find the surface ores
almost exclusively carbonates, silicates and other oxy-
salts. In many copper veins, the copper has almost
wholly disappeared, the sulphurets having been oxydated
to sulphates, which, being soluble in water, have washed
out, leaving a porous iron ore, or a peculiar rotten,
weathered, stained quartz upon the surface. This is
called by the Germans the "iron hat," and by the
Cornish miners "gossan." The depth to which these
alterations extend is very variable. Sometimes it is
confined to the surface, the sulphurets remaining unde-
composed up to the soil. Usually it reaches to a depth
of a hundred feet, and it has been known to be still
quite evident at three hundred feet below the surface.
To recapitulate the practical points, we may say that
true fissure-veins are deep and do not run out or sensi-
bly diminish in contents of ore at any depth which has
yet been reached ; while segregated and gash veins, and
the various irregular deposits, though often very rich as
far as they go, cannot be relied on as having the same
permanence with a true vein.
15
170 MINES AND MINING.
MINING OPERATIONS.
The presence of valuable veins of ore is recognized
by surface indications, or by a series of systematic ex-
plorations. The former can rarely do more than estab-
lish a vague probability, and those which are still relied
upon in some places, are altogether futile. Such are
the heat of thermal springs, gratuitously attributed to
the decomposition of pyrites ; the impregnation of run-
ning water with metallic salts which may have come
from some very remote point. If, however, a small rill,
in a rocky region, should be discovered to contain at its
source, metallic salts, it will generally be safe to infer
the presence of ores somewhere in its immediate neigh-
borhood. Streams impregnated with sulphates of cop-
per and iron, have been known to issue from rocks con-
taining copper pyrites, one of the most valuable ores of
that metal. It must be borne in mind, however, that
this ore may be diffused through the strata, and not con-
centrated in a vein, in which case, it will rarely pay for
the labor necessary to be expended upon it. Springs,
heavily charged with ferruginous matters, are no bad
indications of the neighborhood of workable beds of
iron ore, especially in alluvial and carboniferous re-
gions.
A knowledge of geology is essential to any one who
would form an opinion as to the value of a country for
mining purposes. It enables him at once to exclude a
large number of minerals, which could not be found
in the regions under consideration. It saves him the
trouble of digging for substances which there is no pro-
bability of finding, and enables him to seek for infor-
MINES AND MINING. 171
mation where" nature has been at the trouble of disclos-
ing it to him.
A vein cannot be expected to escape the ordinary
weathering and decomposing influences of the atmo-
sphere, the rain, and the frost. The surface overlying
it will probably be covered with the fragments which
have been detached from it. Thus, in a chrome-iron re-
gion, the position of the vein is indicated by the pre-
sence of angular fragments of the gangue, stained of a
peculiar yellowish green. In the Hartz mountains, the
iron hat to which we have already alluded, has been
found to overlie valuable veins of lead and silver. The
weathered and decomposed quartz, and the porous iron
ore, called gossan, is in many regions regarded as a val-
uable surface indication of copper. These indications
will be rendered more certain by a careful study of the
general character of the veins in a district. Thus, for
example, if in any region, ores of copper should be
found largely intermingled with magnetic iron, a defin-
ed band of fragments of the latter ore lying upon the
surface, would afford sufficient inducement for explora-
tion below. When the ores of a vein lie high, they
will also be found distributed over the surface. Thus
the presence of stains of carbonate or silicate of cop-
per, in fragments of rock differing from the general
masses of the country, and still more the occurrence of
bits of sulphuret similarly imbedded, would afford good
reason for believing a workable vein of copper ore to be
in the neighborhood.
In all examinations of this kind, the action of water
must be borne in mind. As streams sweep from hills
172 MINES AND MINING.
into valleys, they carry with them fragments of various
kinds of rock. By carefully observing these, and trac-
ing them to their sources, the veins from which the me-
talliferous pebbles were originally detached may be
found. Water also acts directly in exposing to our view
the mineral wealth of a region, by making, in the differ-
ent ravines and gulleys, so many natural geological sec-
tions in which we can trace the veins. These, even
though barren, provided they contain the same gangue as
the productive lodes of the district, deserve attention,
as they may become metalliferous in the course of their
descent into the earth.
It may happen, when the veinstone is much harder
than the surrounding rock, that the joint action of air
and water may wear away the latter more rapidly than
the former, so that the vin may remain a kind of wall,
protruding above the common level of the soil. Such a
dyke exists at Mouzias, in Algeria, where several lodes
of heavy spar and spathose iron, containing a little gray
copper, traverse a soft and marly soil that offers little
resistance to the action of water. In consequence, the
heavy rains have washed away the softer clay, and left
the more solid outcrop of the lodes standing. In some
places this wall is fifteen or twenty feet high, and cuts
all the different formations of the country.
The most careful examination of the surface, however,
often fails to communicate any satisfactory information
as to the metallic wealth of the region examined. Then
artificial excavations become necessary. If the vein be
well developed near the surface, an open cut or trench
will often disclose its character. The more common me-
MINES AND MINING. 173
thod of procedure, however, among the Cornish miners
is what they term shading or costeaning. ' This consists
in sinking a series of pits about three feet wide, six
long, and deep enough to penetrate the alluvial soil and
sink a few feet in the rock. If the direction of the veins
of the neighborhood is known, this line of pits should
cross it at right angles. If the region is wholly unex-
plored, two series of pits must be sunk at right angles
to one another. These isolated shafts are now joined by
galleries, so that it is impossible that any vein should
escape detection.
The presence of a promising vein being determined,
the next thing is to make the necessary openings for
working. Open cuts are out of the question, for the
riches of a vein always lie deep below the surface, and
the upper portions are usually quite poor. There are a
number of points to be taken into consideration in
excavations for mining purposes. The surface water
and rain must be kept out of them, and the greatest
care must be taken to get rid of the deeper water in the
simplest and cheapest manner. It is necessary also to
provide for the ventilation of the mine.
The first step, if the conformation of the country ad-
mits of it, is to devise an adit-level or horizontal gallery
from the lowest possible point of an adjacent valley di-
rectly upon the vein. This will, of course, drain all the
work above the level at which it intersects the vein, and
the skill of the operator is shown in reaching this at the
least expenditure of time and labor, and cutting it at
the lowest possible point. Sometimes but a few feet, at
others many fathoms of perpendicular descent can be
15*
174 MINES AND MINING.
drained by these galleries. The economy is great, as
they save the constant outlay in machinery for pumping
up the water. Of such importance are these galleries
esteemed, that sometimes a number of mines are drained
by a single adit driven at their joint expense. So long
as the excavations are kept above the adit-level, it is of
course unnecessary to use machinery for pumping, and
when they have been sunk below it, the water need only
be raised to it, and not to the surface of the ground.
In large mines, every foot saved in this way is import-
ant, and large expenditures are justifiable, which will
effect a slight reduction.
It is desirable, if possible, that the adit should be
driven on the vein itself or close beside it, so that it may
be broken into from time to time, and its character and
richness determined. Where this is impossible, it must
be driven to the vein. It is necessary that the adit
should be inclined only sufficiently to allow for the ready
flow of the water. If it be too near a dead level, it will
fail to accomplish its purpose, if too steep, it will strike
the vein unnecessarily high.
The next thing to be done is to sink a shaft, to inter-
sect both the vein and adit or a cross-cut leading from
the latter. If the vein be nearly vertical, it is custom-
ary to sink the shaft directly upon it, unless its underlay,
or the angle it makes with the perpendicular, is too
irregular, in which case it is sunk by the side of the
vein and connected with it by cross-cuts. When the
lode has an underlay of 45, it is usual to sink vertical
shafts upon it. The dip of the vein having been ascer-
tained, it is easy to decide upon a point at which a
MINES AND MINING. 175
shaft must be opened, in order to strike it at a given
depth. After striking the vein, the shaft may be push-
ed through it, for some distance into the non-metallifer-
ous rock. The vein can then be attacked, if necessary,
both on its upper and its under side, by driving cross-
cuts from the shaft. In the Lake Superior region, the
shafts in veins of such an underlay are driven in the
vein itself, following its dip, and the method has proved
to be economical. In such shafts, a double tram-road is
laid, and the ore is loaded on cars in the levels and run
up to the surface. The verticle shafts are employed in
England, and are always to be preferred when there are
several parallel veins to be worked by the same excava-
tions, or when they are used in part for the purpose of
exploration. The size of the opening of a shaft neces-
sarily varies with the purposes it is required to subserve.
If it is to be used as an engine-shaft, or that in which
the pumping machinery is placed, at the same time that
ore is raised through it, it must be from twelve to fifteen
long by six or eight wide.
Of course, the bottom of the shaft would soon become
obstructed by the fragments of the workings, as well as
flooded by water, if measures were not taken to remove
both these accumulations. Buckets are provided for the
ore, which are termed by the Cornish miners kibbles.
In Cornwall, they are made of sheet-iron, and each holds
about three hundred weight of ore. One hundred and
twenty kibbles are supposed to clear a cubic fathom of
rock. Until the shaft has got below the depth of a hun-
dred feet, the only lifting arrangement necessary is a
windlass, worked by hand. The kibbles and their ropes
176 MINES AND MINING.
are so arranged that they pass one another in the shaft,
so that when one bucket is descending, the other is as-
cending. As the shaft becomes deeper, greater force is
required, and horse, steam or water-power is resorted to.
The machine employed for this purpose, is called a
whim, and is simply the original windlass enlarged and
set on end. It consists of an upright post turning in a
socket at its lower, and in a beam at its upper extremity ;
a cage or drum, round which the rope is wound ; and a
pair of long arms, which correspond to the handle of
the windlass. The beam in which the upper end of the
axle turns, is supported by strong timbers firmly planted
in the ground and strengthened by braces. In order to
convert the horizontal motion of the rope around the
drum, into a vertical motion in the pit, the ropes are
passed over pulleys set in a frame work erected over the
mouth of the shaft. The power is of course applied to
the extremities of the arms. Steam is only used for
shafts over two hundred feet in depth, after the value of
the mine has become fully established. In this country,
small horizontal high-pressure engines are usually em-
ployed ; in Cornwall the low-pressure engine is pre-
ferred.
As the upper part of the shaft is exposed to all the
changes of temperature of the surface, the rock will be
liable to crumble and fall in. In order to avoid this, it
is necessary to protect the walls of the opening with
some sort of covering. For this purpose, timber is gen-
erally used, though sometimes its place is supplied by
masonry. It is stripped of its bark, as that, by absorb-
ing and retaining moisture, accelerates the decomposi-
MINES AND MINING. 177
tion of the wood. With this exception it is as little
dressed as possible. Resinous woods, such as pine, are
much less durable than the harder varieties.
A second shaft is now to be sunk at a suitable distance
from the first, and the two are to be connected by a gal-
lery, usually termed a drift or level. The distance of
these shafts varies with the nature of the surface, the
richness of the vein, and the depth of it which can be
worked. A hundred yards has been stated to be the
average distance between two shafts in a vein of moder-
ate width and richness.
The shafts being steadily prolonged downward, the
mass of the vein is cut up into a series of parallelopipe-
dons, by levels driven through it and following its direc-
tion. If the shafts are at too great distance apart for
the convenience of working, the levels are connected by
shallow shafts, called winzes. The usual perpendicular
distance between the levels is ten fathoms or sixty feet,
reckoning from the floor of the upper to the roof of the
lower level. The customary dimensions of these galle-
ries are six feet in height by three in breadth. By
these the mine is fully opened, and if they are driven
upon the vein, ore is continually being taken out, so
that if the lode is tolerably rich, the expenses of the
opening are more than defrayed. Sometimes it is con-
venient to drive the levels by the side of the vein, in
which case, the wall is broken through from time to
time.
The masses thus marked out are removed by sloping
or working in steps, the object of which is to remove all
the rock of the vein that is worth taking down. There
178 MINES AND MINING.
are two methods of doing this, known as underhand and
overhand stoping.
If it be determined to proceed by the first plan, a
scaffold is erected in the shaft, six feet below the floor
of the upper level, and the workman begins to take out
the mass between that floor and the scaffold. As he
advances, he fixes in the walls of the cavity, strong tim-
bers, called stulls, upon which he lays a floor of plank
for the reception of his debris. It is necessary that
these should be very strong, as they have to support a
great superincumbent weight of fragments of rock. As
soon as the first workman has cut away a block six feet
high, three wide, and six or eight long, another is set to
work on a scaffold six feet below him, and when he has
penetrated a like distance, a third attacks the rock six
feet lower yet, and so on till the roof of the lower level
is reached. In this way the working resembles a series
of gigantic steps, each workman being six or eight feet
in advance of the one next below him.
If the second plan, or overhand stoping, be resolved
on, a scaffold is erected in the shaft, on a line with the
roof of the lower level. A workman placed upon this,
commences to cut away the rock at the re-entering angle
made by the wall of the shaft and the roof of the level.
He constructs a floor in the same manner as in under-
hand stoping. When lie has advanced six or eight feet
and removed all the ore six feet above the floor he has
constructed, another is set to work six feet above him,
and so on until the floor of the upper level is reached.
It will be perceived that this method is the very reverse
of the last, so that the men appear to be working un-
MINES AND MINING. 179
derneath a great staircase, instead of on the face of its
Each mode has its advantages. The former enables
the workman to stand upon the body of the vein itself,
with his work before him, and not liable to be injured
by splinters from the roof ; but he is also compelled to
employ an enormous amount of timber to sustain the
rubbish. The latter plan, with the exception of the oc-
casional discomfort of his attitude is the easiest for the
miner, as the separation of the ore is aided by the force
of gravity. The amount of timber employed in this
method is less than in the former, but the sorting of the
ore is more difficult, because the rich ore is apt to be
covered with the heap of rubbish among which it falls.
It is not necessary to enter into a description of the
miner's implements, the picks, sledges, &c., or to take
up space in describing the operation of blasting, as all
this must be familiar to our readers. We may say, how-
ever, that water need not deter the novice in mining
operations from using gunpowder. All he has to do, if
he cannot dry the cavity, is to secure his powder in a tin
case, or in a cartridge bag rendered impervious to
water.
It sometimes happens that the rock is so extremely
hard, that the ordinary tools produce little or no im-
pression on it. This is the case in the Rammelsberg,
where the vein is large and rich, but exceedingly diffi-
cult to work. To give an idea of its hardness, Dr. Ure
relates an experiment tried there in 1808. A man set
to work to bore a hole for blasting. He labored assidu-
ously during 11 posts, of 8 hours each, in all 88 hours,
180 MINES AND MINING.
without being able to get deeper than four inches. In
accomplishing this, he wore out 126 bores, dulled 26
others, which had been retipped with steel, and 201
which had been sharpened, besides consuming 6 pounds
of oil to give him light, and half a pound of gunpowder
for the blast.
In cases of this kind, fire is employed to destroy the
cohesion of the masses to be wrought. At the Ram-
melsberg, this agent is usually brought to bear upon the
roof of the vault. Piles of faggots are so arranged
throughout the galleries, that the top of each shall not
be more than two yards from the roof of the vault.
This having been attended to, together with the other
work of the mine, during the week, the fire is kindled
on Saturday. At 4 o'clock, in the morning, the fires
are lighted, the fireman beginning in the upper ranges
so that the vapors from below cannot stifle the newly
made fire. He descends from level to level, kindling
the pile throughout the mine, and does not get through
his work till 3 o'clock in the afternoon. Sulphur and
arsenic are burned off, loud detonations occur in the
vaults, and some splinters of ore fall, though most of
the heated mineral retains its place on the roof. The
fire is left to itself till Monday morning, when a man
again descends and extinguishes such of the fires as
have not gone out. Should the action of the former
piles be incomplete, new ones are built in the same spots,
after the miners have stopped work for the day. On
Tuesday, all hands are at work, detaching the friable
mineral from the roof with long iron forks, and prepar-
ing new piles' to be kindled again on Saturday.
MINES AND MINING. 181
All these workings which we have described, require
a support of some kind. In some cases, the rock is so
friable that it is impossible to advance at all without at-
tending to this before the excavations are made. These
supports are either of timber or of masonry. The for-
mer is more frequently adopted ; in this country it is
exclusively employed.
To timber with complete frames, is to construct a sort
of gallery of logs within the excavation. A floor piece
or sole is laid, on which rest upright posts, inclining a
little towards each other, so as to make the ceiling nar-
rower than the floor. A cap is now put on the stand-
ards, and they are morticed into it so that they cannot
possibly approach nearer to each other. When the rock
is very friable, facing boards, which are planks, or spars
of cleft wood, are placed horizontally behind these
beams, both on the roof and on the sides. The size of
the timber and the distance between the stanchions de-
pend entirely upon the pressure to be resisted. When
the floor is sufficiently solid, the uprights rest directly
upon the rock. Sometimes only one side requires tim-
bering, the other being sufficiently firm. In that case,
pillars are set up only on one side ; on the other, the
joists rest in holes cut in the rock. It may happen that
the roof alone requires support. Then the timbers are
simply laid across the top, being secured at both ends in
sockets cut in the rock.
When masonry is employed, it is almost always arch-
ed. Sometimes when the floor also requires attention,
it is built in the form of an ellipse, like an egg-drain.
The processes of blasting, the combustion of the can-
16
182 MINES AND MINING.
dies and lamps, as well as the respiration of the work-
men, must soon thoroughly contaminate the atmosphere
of the narrow underground passages we have heen de-
scribing. The emanations from the mine itself, result-
ing from the decay of wood, the decomposition of mine-
rals, the occasional evolution of arsenical and mercurial
vapors, all contribute to the same results. It is there-
fore absolutely necessary to secure such a current
through the various openings as shall sweep out these
poisonous vapors, and furnish the workmen a sufficient
amount of pure air for respiration. Numerous contri-
vances have been resorted to for the accomplishment of
this necessary object. Very often it is effected by mere-
ly arranging the openings of two shafts at different ele-
vations externally. The column of air within the mine,
being lighter in winter and heavier in summer than that
without, the air naturally flows out of the higher eleva-
tion in the former season, and the lower in the latter.
In long galleries two compartments are sometimes made,
the one larger than the other. In the smaller, the air
sooner comes to the temperature of the rock, and this
difference between the two compartments is sufficient to
establish a current. These currents are often obtained
by raising a chimney sixty feet high over one of the
shafts, which has the same effect as sinking shafts at
different external levels. There are also more complex
contrivances for pumping the foul air or forcing the
pure air in, which our space will not permit us to de-
scribe.
The ore which is separated with the vein-stone in
mines, is rarely sufficiently charged with metal to be
MINES AND MINING. 183
merchantable without some preliminary dressing. The
methods of concentrating the ore will now demand our
attention.
As the ores are but sparingly diffused through the
vein, being mixed with a great quantity of stone, it is
the miner's duty to make a preliminary sorting of them
before sending them up to the surface. He separates
those which seem to contain no metallic matter, from
those which have ore diffused through them. The for-
mer are allowed to remain in the mine, where they are
used for filling up in part, the cavities made by the pro-
gress of the excavations.
When the ores selected by the miner reach the sur-
face, they undergo a second sorting by hand. The vari-
ous pieces are broken up by hammers into small frag-
ments, and are usually divided into three varieties : 1st,
The gangue or stony matter, which is thrown away; 2nd,
The rich ore which may be sent directly to market; and
3rd, The fragments which, containing little ore, are to
be sent to the stamps or rolls for further dressing.
The latter, in order to undergo the final separation of
ore from dead rock, must first be reduced to the proper
degree of fineness. For this purpose, they are subject-
ed to the action of machinery. One of- the most com-
mon forms is a crusher, an apparatus composed essen-
tially of two iron rollers revolving in opposite direc-
tions, worked by either steam or water-power. Their
bearings are so arranged as to slide in grooves, and con-
sequently, to allow the cylinders to be brought closer
together, or to be separated to a greater distance. To
prevent accidents from the sudden jar given to the ma-
184 MINES AND MINING.
chinery by the harder pieces of stone, a lever is attach-
ed to a sliding bar and shoulder, so that its outer extre-
mity when loaded by a suitable weight, will keep the
rollers in sufficiently close apposition. When a frag-
ment, so hard as to endanger the apparatus, becomes
entangled between the rollers, the weight rises, the jaws
open and allow the piece to drop. The ore to be crush-
ed is gradually let fall between the two rollers from a
hopper, and, as it passes through, is received into a
cylindrical sieve, inclined towards the horizon. This, be-
ing agitated by the same power which moves the roll-
ers, allows a portion to pass through upon the floor,
while the rest, being too large for its meshes, falls into
the buckets of an endless chain which carry it up to the
level of the hopper, when it is again passed through.
In some cases a stamping-mill is preferred to a crush-
er. In this apparatus, a long horizontal axle is set in
motion by steam or water-power. This axle is provided
with a series of cams arranged in spirals round its cir-
cumference. Yertical wooden beams shod with heavy
pieces of iron, are provided with tongues so as to be
caught and lifted by the cams during the revolution of
the axle. The tongues and cams are so arranged as
to enable each iron shoe to give three blows during one
revolution of the axle, in a constant succession, so that
when one beam is falling, the beam next it is rising.
The iron shoes fall upon the mineral contained in a
large trough. This trough is provided with several
openings, which have over them a grating of perforated
sheet-iron. A small stream of water passes through the
arrangement, sweeping out, through the holes of the
MINES AND MINING. 185
grating, those fragments of ore which are sufficiently
pulverized. They are received in a pit prepared for that
purpose.
The size of the stamp-heads varies with the nature of
the mineral to be broken. Their average weight in
England, is from three to four hundred pounds. The
heads are attached to the lifters by a wrought iron
shank, which is let into the end of the liftier, and made
fast by shrinking over it two bands of iron.
The ores thus comminuted are usually concentrated
by washing. The principles upon which this process
depends are very simple. If, for example, a number of
substances varying in form, size and density, be swept
along by a current of water, or allowed merely to fall
through water, they will arrange themselves in accord-
ance with the resistance or the impulse they experience
from the fluid. If they are alike in form and size, but
vary in density, they will after falling through water,
arrange themselves in the order of their specific gravi-
ties, the heaviest being at the bottom, the lightest on
top of the series of strata. If their form and density
be the same, but their size different, the largest particles,
moving more rapidly than the others, will of course ar-
rive first at the bottom, and must necessarily occupy the
lowest layer of the sediment. The reason for this is to
be found in the fact, that though their volume increases
as the product of their three dimensions, the surface
exposed to the resistance of the water increases only as
the product of two of these dimensions, so that the re-
sistance is less in proportion in the larger pieces. If
the pieces have the same volume and density, but differ
16*
186 MINES AND MINING.
as to surface, (which of course involves a difference of
form,) it will be found that those which possess the great-
est surface, being most resisted, fall slowest and form the
upper layer.
From these considerations, it is evident that the ores
to be dressed, should be, as nearly as possible, of the
same size, as then they will subside in the order of their
specific gravities, which is what the miner desires. Prac-
tically, this is effected by the use of sieves, which classi-
fy the pounded materials as to size. Their form is of
course, beyond the control of art, and this interferes to
a slight extent with the result.
It is evident that there are but three classes to which
the broken fragments can belong. They must either be
composed of the ore exclusively, of the non-metallic
minerals exclusively, or of a mixture of the two. In
the process of washing, the pure ore sinks to the bot-
tom, the mixed ore comes next above it, while the top
layer is composed of the non-metallic substances.
One of the most ancient methods of employing water
for the purpose of classifying ores, was the use of the
hand sieve. This is a cylinder closed at the bottom by
a perforated sheet of copper. The miner fills it with
the mineral he wishes to operate upon, introduces it
into a large tub of water, and works it with a sort of
undulatory motion. The water streaming up through
the holes in the bottom, offers a variable resistance
to the different substances in the sieve ; so that the
heavier or richer particles sink to the bottom, and the
more earthly matters accumulate on the surface. These
the miner scrapes off with a piece of thin iron, or with
MINES AND MINING. 187
his hand, and repeats the operation, as long as the sur-
face pieces continue poor. These are not all rejected;
those which are considered metalliferous enough to pay
for a second sorting being laid aside for further treat-
ment. That which accumulates at the bottom is taken
out and sent to market. This process is called jigging
or sieve washing.
On the Continent of Europe, a modification of this
method has been generally adopted. To a beam, one
end of which carries a box which is filled with stones to
act as a counterpoise, is attached by means of a rod, a
sieve resembing that used in washing by hand. This
rod is fastened to the beam midway between the turning
pivot and the end, which carries another rod swung
on a pivot. This is worked up and down in a cylinder,
and communicates a plunging motion to the sieve. The
process is precisely the same as in hand washing. For
the sake of convenience a table is placed near the deep
tub to receive the ores.
In Cornwall, copper ores are washed by a much better
and larger apparatus. " This consists of a large box, cover-
ed with a tight wooden floor, in the centre of which, is a
circular metallic trough, perforated with six holes, each
about two feet in diameter, and into all these openings
a sieve is closely fitted. A large piston working in a
cylinder placed in the centre of this arrangement, and
which is moved by an eccentric, driven either by water
or steam power, is made to alternately raise and depress
the level of the water in the box and consequently
also in the sieves, which are fixed water-tight into the
rings on the top of it. By this motion of the water, the
188 MINES AND MINING.
particles of minerals contained in the sieves are
made to arrange themselves according to their several
densities, and when it becomes necessary to remove a
sieve from its place for the purpose of scraping off the
less valuable and lighter portion of its contents ; its
place is supplied by another, which is kept ready filled
to occupy the same ring when required."
" Of the portions which are scraped off from the sur-
face of the sieve, the lightest contains little or no metalic
ore and is thrown away ; but the second, consisting of a
mixture of gangue and metalliferous substances, together
with the finely divided dust which passes through the
holes of the sieve, is sent to the stamping mill, where it
is reduced to the state of much finer powder, by which
treatment greater facilities are afforded for its separa-
tion from earthy impurities. When the ores are not
stamped dry, the water and work (fine sand) escaping
through the gratings of the machine are conducted into
a sort of reservoir, where the heavier particles are first
deposited, and the poor and consequently lighter parts,
are removed to a greater distance. By this process, a
certain classification of the work is effected, as those
portions which have been carried by the force of the
water beyond a given point, are collected in a separate
basin from those which have not arrived so far from the
stamping-mill." *
The arrangements for washing the finely pulverized
ores, varies in different places, and with different ores.
The G-erman chest is a long box placed in a slightly
inclined position, and having in its lower end, a series
* Phillips' Metallurgy, p. 113.
MINES AND MINING. 189
of holes, closed with wooden pegs. At the higher end,
a platform is placed to contain the ores, over which
plays a small stream of water. This carries off in sus-
pension the finer particles of the ore and, deposits them
at distances varying inversely as their specific gravity.
As soon as the box is full of water, the stream is stopped,
and the lower peg being withdrawn, the water and fine
powder are allowed to flow off into reservoirs, where the
solid matter subsides. As the chest becomes gradually
filled with the deposited sand, peg after peg is withdrawn,
till at last, when quite full, the uppermost peg is taken
out. The heaviest ore is found to be deposited near the
head of the pit, and the others distributed in the order
of their richness, at varying distances. The first is
ready for smelting, the other portions require further
treatment.
The sleeping or twin tables are two inclined planes,
about twenty-five feet long, placed side by side, and
provided with ledges to prevent the ore from running off
at the sides. At their upper extremities, is an appara-
tus, worked by a small water-wheel, for thoroughly in-
corporating the fine ore with water. Thus mingled, it is
introduced on the upper part of the planes, and a stream
of water allowed to flow over it. This separates the
different substances in the order of their densities, the
lighter being swept off by the current. The workman
accelerates this process of separation, by sweeping the
ore up the planes with a small broom, until he is satisfied
that the ore is fully concentrated, when it is suffered to
fall through an opening near the lower end of the plane,
into receptacles prepared for it. The inclination given
190 MINES AND MINING.
to these tables varies with the fineness of the powder
they are expected to sort, being greater the coarser the
grains.
The percussion table is also an inclined plane, but it
is swung by chains, which at the upper extremity, at-
tach it to fixed beams, at the lower to a moveable lever,
cams on the axle of a water-wheel, strike on an upright
connected with the table, and subject it to repeated con-
cussions. The ore is mixed with water and allowed to
flow over the surface, as in the last described apparatus,
but the repeated jars, assist in the separation of the
light from the heavier particles, so that the apparatus
is, in principle, a sort of combination of the sleeping
table and the jigging machine.
In Cornwall buddies and racks are used instead of the
tables.
The nicking -buddle is a long inclined trough, or cis-
tern, resembling a German chest. At its head is an
inclined shelf, higher than the floor of the cistern,
terminated above by a wooden head-board, provided
with an opening closed- by a plug, which regulates the
admission of water from a little dam behind it. The
ore having been placed on the higher shelf, a stream of
water is let on, meanwhile a boy stationed in the pit,
alternately smooths and notches the layer of ore, with
a sharp shovel. The ore is soon washed from the head,
and when it has fallen in the body of the apparatus, the
boy continually sweeps it back towards the head again.
This facilitates the separation of the light from the heavy
particles, the former being carried down towards the
bottom of the buddle. When the deposit of heavy par-
MINES AND MINING. 191
tides has sufficiently filled the cistern, the light gangue,
suspended in the water, is drawn off. The heavy sand
is drained, and divided into three portions according to
its richness. The ore nearest the head of the huddle is
usually rich enough to be smelted ; that next to it is laid
aside for a second puddling, while the lowest and light-
est is sent to the rack.
The rack consists of a smooth wooden flooring, with
strong ledges around it, inclined to the horizon, and
provided, like the huddle with an upper shelf and head-
board. It rests upon pivots, so as to enable the work-
man, when desirable to turn it on the pivots. The water
is let on to the lower level over a flap, swung on leather
hinges.
The ore is laid on the higher shelf, and alternately
grooved and flattened by means of a wooden hoe. The
water carries it down to the lower level, where it is
moved by a rake to the highest point of the arrangement,
the water flowing continually over it. A small broom
is also used to complete the washing, the earthy matter
being suffered to flow out into reservoirs prepared for
its reception.
When a sufficient layer of mineral has by this manip-
ulation been collected on the table, it is made to take
a quarter revolution on its axis, and when in a vertical
position, is caught by a wooden spring, which holds it
firmly in that situation.
The person working the frame, now washes off the ore
by the use of a wooden bowl with a long handle, which
causes it to fall first into the angle, formed by the
meeting of one of the sides with the floor, and alternately
192 MINES AND MINING.
into boxes placed beneath for its reception. In this,
as in the preceding examples, the richer ore will be
found to accumulate at the upper end of the inclined
plane, and therefore the washed ore is divided into two
parts, each of which falls into a different receptacle.
" This division is made by a fillet, placed on the side
of the rack at about equal distances from its two extre-
mities, and which, when the plane is brought in a pro-
per position for washing off the deposited metalliferous
grains, forms a dam, and causes that which is deposited
in the upper part of the floor to fall into one box, or
cover, whilst that which is deposited in the lower, falls
into another."*
* Op. cit.
CHAPTER IV.
MINES OF COPPER.
COPPER is very widely distributed over the surface of
the globe, and occurs in many geological formations.
Often it exists in mere detached minerals, not connected
with any great mass of ore, and at others it is so abun-
dant that it may be considered inexhaustible. The
great mining districts have so far been found in two dis-
tinct geological positions ; first, in the older crystalline
rocks, especially the metamorphic palaeozoic, and in the
igneous formations associated with them ; secondly, in
the strata lying between the coal measures and the lias,
which is the lowest member of the Jurassic or oolitic
group. The best examples of the former mode of occur-
rence are the mines of Cornwall, Australia and Lake
Superior. The veins are either segregated, or true fis-
sure veins, the former being sometimes large and pro-
ductive, but the latter being more permanent. Of the
second mode of occurrence, the schists of Mansfeld,
and the Ural mines are examples. In the new red
sandstone of our country, which is usually referred to
the Triassic group, but lately classified among the lower
Oolitic rocks, copper ores are also found. Above the
new red sandstone few important deposits of copper have
been discovered.
17
194 MINES OF COPPER.
EUROPEAN MINES.
British Mines. Cornwall is the great district of Bri-
tish mining, and as the mines of that region are usually
selected as a basis of comparison with other deposits, it
will be well to consider somewhat carefully its geology.
The mines of Cornwall occur either in granite or the
schistose rocks that accompany it. Of these, the killas*
or greenish argillaceous slate and the growan or granite
are the most important for the copper miner. Porphyry,
called by the miners, elvan, also occurs, but it is chiefly
valuable for the tin which it carries. The term elvan
is likewise applied generally to any rocky mass that oc-
curs in the slates and granites and displaces the rocks.
The porphyry usually occurs in long narrow dykes,
some of the seams having been traced for twelve miles.
The granite is found in six great isolated masses, as
well as in smaller patches. The great masses have a
general linear direction northeast and southwest. It is
remarkable for carrying a great deal of schorl or black
tourmaline, which is especially abundant along the con-
fines of the granite and slate. The latter rocks abut
abruptly upon 'one another, the only change which is
noticeable in the killas being a condensation of the mass,
the granite frequently penetrating it. De la Beche
makes a distinction between the mica and hornblende
slates, and the grauwacke group, a collection of sedi-
mentary deposits varying from the finest roofing slates
to the coarsest possible conglomerates.
The same eminent geologist divides the mining dis-
trict of Cornwall and Devon into six groups ; 1st. Tavis-
* This term is also applied to slate in general.
MINES OF COPPER. 195
tock, bearing copper, tin, and silver lead; 2d. St. Aus-
tell, containing tin; 3d. St. Agnes; 4th. Gwennap,
Redruth and Carnborne, a copper region ; 5th. Breagin,
Mazarien and Gwinear, producing tin, copper, lead and
silver; 6th. St. Just and St. Ives, bearing tin chiefly.
The ores of copper and tin are always found in the
neighborhood of the granite or porphyry.
The system of the veins of this district is exceedingly
complex. Mr. Game's classification, adopted by Dr.
Ure, in his Dictionary of Arts, Manufactures and Mines,
is as follows ;
1. Veins of elvan; elvan courses, or elvan channels.
2. Tin veins or lodes.
3. Copper veins running east and west; east and west
copper lodes.
4. Second system of copper veins, or contra copper
lodes.
5. Modern copper veins; more recent copper lodes.
7. Clay veins, of which there are two sets, the more
ancient called cross-fluckans, the more modern called
slides.
These divisions appear to be the result of an analysis
altogether too refined. Sir H. de la Beche, who paid
great attention to these mines, does not attempt to assign
definite ages to the copper veins, so that the third,
fourth and fifth divisions in the above table may be
united in one. As to the tin veins, they are generally
believed to be older than the copper lodes, but even this
idea may be dismissed, since it has been ascertained
that the very same lode may carry tin in one part of its
course and copper in another. The second division of
196 MINES OF COPPER.
the table may therefore be incorporated with the three
following it. We shall then have three classes of
veins.
First, the elvan courses, which follow nearly the range
of the granite rocks, traversing them, and are them-
selves cut by the true productive lodes.
Second, the great metalliferous lodes, which have the
same general direction with the elvans, but which inter-
sect them and consequently are more recent.
TJiird, the cross-courses, or veins and fissures which
run north and south, cutting the east and west lodes at
angles varying from seventy to ninety degrees. They
carry argentiferous lead in some places, but are gene-
rally barren, being filled with clay. Their date is mod-
ern, being supposed to have occurred later than the cre-
taceous period. They are themselves occasionally cut by
what are called the east and west slides.
Of these systems of veins, we have only to notice the
copper lodes. ' Near the surface, where they have been
exposed to atmospheric influences, they are much decom-
posed, and abound in gossan. This is a mixture of
quartz with more or less oxide of iron, containing also
insoluble combinations of other metals. The theory of
its formation is simple. The vein-stone with its metal-
lic contents, having been subjected to the influence of
oxygen, has had soluble sulphates formed in it, which
have been subsequently leached out by rain water. Sul-
phate of iron, decomposing readily, leaves behind it the
hydrated oxide of that metal which gives its foxy red
color to the mass. The less alterable minerals, gold,
ores of silver and tin, remain behind. In the English
MINES OF COPPER. 197
gossans, silver occasionally occurs in sufficient quantity
to be worked. Gold is found in many of them, to the
extent of one or two ounces to the ton, and tin has been
so abundant that the gossans have been mined for that
metal. The depth of this decomposition varies from
twenty to thirty fathoms. All gossans are not equally
valuable indications of the presence of valuable mineral
at greater depth, and experience enables the miner to
form an idea of the prospects of a mining estate, by a
careful inspection of this overlying rock.
The lodes, below the point at which the atmosphere
ceases to act, contain chiefly copper pyrites, mixed
with other ores of copper and with sulphuret of zinc.
The ores are not uniformly diffused through the veins,
but occur in masses of variable size, connected by threads
and strings too small to be worked with advantage, yet
distinct enough to be followed by the miners. The width
of the veins averages six feet, though enlargements to
the extent of twelve feet occasionally occur. The
gangue is usually quartz, often mixed with green matter
resembling chlorite. The veins are generally accompa-
nied by argillaceous bands called the fluckan of the
lode.
The productiveness of the lodes vary with the nature
of the "country," and with the displacements to which
they have been subjected. If they ramify as they
descend, the ore diminishes; but if the various strings
coalesce downwards, the product of ore increases. In
like manner, when different veins unite, the quantity of
ore usually increases. In the Gwennap district, the
east and west veins all become productive, where the
IT*
198 MINES OP COPPER.
great counter-lode cuts them. As a general rule, the
smaller the angle at which two lodes cross one another,
the hetter are the prospects for a great amount of ore.
The elvan dykes have also been found to exert a very
beneficial influence upon the richness of the mine.
The nature of the rock which the veins traverse also
affects the lode. The most productive portions are
always in the neighborhood of the point where the gran-
ite meets the killas. No general rule can be given for
determining the productiveness of a lode in either of these
rocks, there being great variation, in this respect, in
different mines. Thus, of two parallel tin lodes, only a
mile apart, one was unproductive in the slate, and rich
in the granite, while the other was just the reverse.
The slates were formerly considered the best "country"
for copper, but rich mines have been worked in the gran-
ite not very far from its junction with the killas. The
characters of the rock in any formation seem to influ-
ence the yield of copper. Thus, in the Gwennap dis-
trict, the red killas is considered unproductive and the
bluish gray variety alone is believed to justify extensive
working.
As to the yield of a mine at various depths, it has
been generally believed that a true vein grows continu-
ally richer as it descends. Some doubt has been recently
cast upon this opinion, from the fact that in certain old
mines this gradual increase in value stopped at a very
moderate depth, beyond which the metallic contents of
the vein remain stationary, or, according to some autho-
rities, actually diminish. It has been asserted that the
results of working prove that a vein, which is poor at
MINES OF COPPER. 199
the surface, increases in richness to a certain depth,
where it reaches its maximum and then diminishes in
productiveness, while a lode, rich at the surface, contin-
ues good for a certain distance and then begins to de-
crease, at much less depth than the poorer lode. These
statements have been denied on the ground that some
of the deepest mines in Cornwall continue to furnish
great abundance of ore. In connection with this ques-
tion, it must not be forgotten that the time of greatest
prosperity of each mine has been when its workings had
reached a moderate depth, a fact which seems to show
that the increase of ore in the lode at the greater depths,
if it really occur, is not sufficient to meet the augmented
expense of raising it from such very deep levels. For
example, in 1815 the Dolcoath mine was the richest;
in 1817 the United mines stood first; in 1822 the Con-
solidated mines gave the largest product, and since 1845
the Devon Consols have held the first place. The deep-
est mines have been sunk over 2000 feet.
It is very important to consider the dip ; a vein which
has an inclination varying much from the perpendicular,
being rarely very valuable. In a lode which often
changes its inclination, those portions which are most
nearly perpendicular, are usually the richest.
These mines are worked on a grand scale, and with
great skill. The Great adit reaches nearly five and a
half miles, in a direct line ; and if all its ramifications
be taken into account, its length is thirty-five miles. At
its deepest point, it is seventy fathoms below the sur-
face. We subjoin a very brief sketch of some of the
principal Cornish mines.
200 MINES OF COPPER.
The Dolcoath Mine is the oldest in Corn-wall, having
been worked with little interruption for a century. It is
three hundred fathoms deep. It has paid out 300,000
in dividends. In the thirty-six years from 1814 to 1848,
it furnished 238,059 tons of ore, worth 1,361,681.
The G-reat Consolidated Mines are very celebrated.
In 1848, the workings were sixty-three miles long, and
had made a profit of 700,000. From 1819 to 1840,
these mines cleared 500,000, besides expending 100,-
000 in opening the United Mines. During the last
twelve months of that period, they yielded 17,283 tons
of ore, worth 100,279. From 1840 to 1848, there
were taken out 83,660 tons, sold at 490,543, of which,
owing to the heavy expense of the workings, only 32,-
000 was divided among the stockholders. In March,
1854, no dividend having been declared for more than
three years, the price of shares went down ninety per
cent, below par.
The Devon Grreat Consolidated Company, usually
called Devon Consols, has made enormous profits. They
began in August, 1844, with 1024 shares, at 1 per
share, paid in. The ground was leased of the Duke of
Bedford for twenty-one years, at a royalty of one-
fifteenth, to be raised to one-twelfth after 20,000 had
been cleared. The lode, at eighty-four feet from the
surface, was eighteen feet wide, " carrying an immense
gossan." At the depth of one hundred and five feet, the
great deposit was reached. In the first three months of
regular working, the mine cleared over 15,000 ; the
next year, 1846, the profit^ were 39,590. By 1850,
ten shafts had been sunk in the lode, the deepest having
MINES OF COPPER. 201
reached six hundred feet, and one thousand persons
were employed about the mine. Up to January, 1853,
358 had been paid in dividends on each share, and
the original shares of <! sold for .430. Up to that
time, 131,141 tons of ore had been taken out and sold
for 882,742. In 1854, the mine produced 23,174
tons. At present, the mine pays dividends every two
months, and the stock sells at 410 per share.
During the year 1853, sixty English mines paid out
in dividends 329,015, of which two, the Devon Consols
and the Wheal Buller, paid 110,464. At that time,
shares in the latter mine on which 5 had been paid in,
were worth 1,025.
The average annual production of this mining region
has steadily increased until the past year, when it fell
somewhat short. In the Appendix will be found a table
expressing it. It will there be seen that the product
for the year 1853 was more than three times greater
than the annual product at the beginning of this cen-
tury, but that the percentage was one-third lower. The
average yield from 1771 to 1786 was twelve per cent.
of copper, that of the first twelve years of this century,
8.95; of the next twelve, 8.4; of the next twelve, 8,
and of the next, 7.7. In 1853, the product was only
6.6, so that although more ore was sold than ever be-
fore, and at a higher rate, many years exceeded it in
the actual amount of pure metal obtained from the ore.
The average of the first three quarters of 1856, was
6.27, the total produce being 143,200 tons.
The number of copper mines now worked in England
is one hundred and seven, seven of which are not selling
202 MINES OF COPPER.
ores. Of those which are selling, twenty-six are paying
dividends. The entire amount of capital originally in-
vested in all the mines is 1,078,092, on which 2,294,-
478 have been paid in dividends. The annual dividend
is 291,282, or one hundred and thirty-four per cent,
on the capital invested in dividend-paying mines. In
1854, the number of mines was somewhat larger.
Robert Hunt says that one hundred and eleven mines
sold in that year ores in quantities above fifty tons each.
France. There is no copper mine of any importance
in this country. Some time since, mines at Chessy and
Saint Bel were wrought, but they are now abandoned.
The chief interest attaching to them is to be found in
the magnificent crystals of azurite they produced.
Prussia. Mansfeld has long been celebrated as an
exception to the ordinary laws of copper-mining. For
centuries a deposit having none of the characteristics of
a regular vein, has been worked to advantage. The
cupriferous rock is a regular member of a geological se-
ries, and though not more than two or three feet thick,
and containing a very small percentage of copper, its
great extent and extreme regularity admit of its being
profitably worked. The ore is gray copper containing
silver, and the rock which bears it is a bituminous marly
slate.
Near Stadburg, in the district of Liegen, is a silicious
slate which contains numerous particles of carbonate of
copper. These are dissolved out by sulphuric acid, and
precipitated by metallic iron.
Regular veins of copper also occur in various parts of
the kingdom. The entire yield of the country amounted,
in 1850, to 1450 tons.
MINES OF COPPER. 203
Austrian Empire. By far the largest portion of the
copper produced by this empire comes from its depen-
dency Hungary. In Lower Hungary, at Schemnitz,
the mines were formerly valuable, but the region is now
more celebrated for its mining school than for its pro-
ductiveness. At Schrnollnitz, the copper ores are argen-
tiferous, as they also are in the Banat.
At Tsiklova, in the Banat, there is an establishment
for smelting the ore and separating the silver from the
copper. ,The process will be described in the next
chapter. The ores of the Banat occur in irregular de-
posits, near the junction of the sienite with metamorphic
Jurassic rocks. They consist of copper pyrites, with
gray copper carrying silver, blende, iron pyrites and a
little gold. They do not yield more than four per cent,
of copper after sorting by hand.
The annual product of the empire is a little over
3,300 tons.
Spain. The mines of Rio Tinto are the oldest in the
country, having been worked by the Romans. The
water issuing from the old workings is now treated with
iron, furnishing copper by cementation. In 1833, one
hundred and forty tons were obtained in this way.
English companies are now working the Linares mines,
which yield both lead and copper. The entire produce
of the kingdom for 1849 is estimated at 450 tons.
Italy. The Tuscan mines are the best known in
Italy, and they do not produce much. The ores of
Monte Catini occur in contact deposits, and, contrary
to the usual rule, grow richer as they descend.
Turkey. This country produces much good copper
204 MINES OF COPPER.
Russian Empire. The most extensive mines are in
the neighborhood of the Ural Mountains. On their
western flanks, in the governments of Perme and Oren-
burg, the beds of the Permian system are cupriferous
and resemble the copper schists of Mansfeld. The ores,
chiefly malachite, are distributed through thick, gray,
flag-like grits. These contain only about 2J per cent,
of ore, but the beds are so large that, even this small
quantity pays well for extraction. The metal obtained
from them is of very fine quality, and in great request
for making bronze. They furnish about 260 tons
annually, and pay the government a profit of about
$40,000.
On the east side of Ural Mountains the most valuable
deposits occur. The principle mines are the Gum-
eschewskoi, the Bogoslowski and those of Nijny Tagilsk.
At the former place there are no regular veins. The
mine has been worked for more than a hundred years,
on bunches and nests of copper ore, chiefly malachite
and red oxide, contained in argillaceous shales. The
malachite is in large masses ; a cube, three feet and a-
half in diameter, was taken from this mine.
The Tarjinsk mines near Bogoslowski, occur in a Si-
lurian limestone, the strata of which alternate with beds
or dykes of trap. Along the lines of contact occur de-
posits of clay, in which the copper ores are found in
bunches and nests. Fine crystals of native copper
occur here.
At Nijny Tagilsk, the ore lies in hollows of the erup-
tive works, and is mixed up with lumps of limestone and
and other rocks. At the depth of 280 feet there was
MINES OF COPPER. 205
discovered a mass of malachite, estimated to weigh over
580 tons.
The average annual product of the Ural mines during
the ten years preceding 1848, was 3720 tons of copper.
In 1850 it exceeded 5400 tons.
There are other mines in the Caucasus, in the Altai
and in Finland. Those of the Caucasus contain much
ore and give evidences of having been extensively
worked long since. The mines of Altai yield an annual
product of 400 or 500 tons.
The average annual amount of copper produced by
Russia, has been 4,540 tons. It is on the increase. In
1849 it was 6,546, and in 1850, 6,449 tons. But little
is exported.
Norway and Sweden. There is not a very great
amount of copper produced by this northern Peninsula.
That obtained in Norway is reputed better than that
from the Swedish mines.
The mines of Alten, in Norway, latitude 70, are the
most northern in the world. They have been worked
by an English Company since 1826 ; the formation in
which they occur belongs to the metamorphic palaeozoic
or azoic, with which are associated diorite and
hornblende. At Kaafjord, the ores occur in igneous
rocks cutting slates. In the former alone they are pro-
ductive, often, indeed they disappear entirely in the
slates. On the Raipasvara Mountains, a few miles from
the last named locality, another group of copper lodes
occurs in compact subcrystalline limestone, intercalated
with slates. The principal vein is six feet wide, dips
vertically, and contains near the surface, gossan with car-
18
206 MINES OF COPPEK.
bonates and arseniates of copper but lower down the
ore is variegated. The veins are unproductive in the
slate. At Roraas, there are no veins, the ore being
disseminated in chlorite slate, forming " fahlbands."
The deposits in Sweden occur chiefly in quartzose,
micaceous and calcareous beds, contained usually in
gneiss. Dalecarlia is the principal mining region. The
mines of Garpenberg, in that province, have been worked
since the twelfth century and are now 1000 feet deep. At
Areskuttan, the ores are pyritous, and diffused through
crystalline schists, forming fahlbands. At Gustavsberg,
the fahlband averages thirteen to sixteen feet in thickness
and often exceeds that. The ore yields only from three
to four per cent, of copper.
Falun is a famous mining region, now nearly exhausted.
The ore is poor, containing, after picking by hand, only
3J to 4 per cent, of copper. The rock in which it is
contained, is a gray quartzose mass, containing little
plates of mica. It is divided into irregular ovoid masses,
by curved or undulated bands of chlorite, called
" skolar." Along these are found the principal con-
centrations of the ore. The Storgrufva, or great mine,
has been worked for centuries upon the larger of these
masses, which is now found to be a huge inverted cone,
with a rounded apex. The surface dimensions of the
mass, are 800 by 500 feet. The interior is chiefly iron
pyrites, the copper ore lying outside and forming a kind of
envelope for it. The depth of the workings is about 1,100
feet.
The entire produce of Sweden in 1850 was a little
over 1,400 tons, that of Norway, for five years before,
averaged annually 567 tons.
MINES OF COPPER. 207
AFRICAN MINES.
Algiers. Near the foot of the Moazaia Pass, a cop-
per mine has been worked for some time. The veins
consist of spathic iron and grey copper ore, and are
found in strata belonging partly to the gault and
partly to the middle tertiary.
ASIATIC MINES.
India. Copper is found in the Ramghur Hills, about
150 miles from Calcutta. The ore is said to be abun-
dant, but the mines are badly worked. The natives
smelt the ore with charcoal.
Japan. The copper from this secluded empire has
long been celebrated for its purity. About a thousand
tons are annually exported, chiefly to China and Hol-
land. But little is known concerning the mode in which
it occurs. From what Ksempfer says, much of it would
appear to be native. We quote his words.
"It is at present dug up chiefly in the provinces of
Suruga, Atsingo and Kijnokuni. That of Kijnokuni is
the finest, most malleable and fittest for work of any in
the world. That of Atsingo is coarse, and seventy cat-
tis of it must be mixed with thirty cattis of the Kijnese
to make it malleable and fit for use. That of Suruga is
not only fine and without faults, but charged with a con-
siderable quantity of gold, which the Japanese at pre-
sent separate and refine much better than they did for-
merly, which occasions great complaints among the
refiners and Brahmins on the coasts of Coromandel. All
the copper is brought to Saccai, one of the five imperial
towns, where it is refined and cast into small cylinders,
208 MINES OF COPPER.
about a span and a half long and a finger thick, As
many of these cylinders as amount to one pickel, or
125 pounds in weight, are packed up into square wooden
boxes and sold to the Dutch. There is besides a sort of
coarse copper, which is cast into large, flat, roundish
lumps or cakes, and is bought a great deal cheaper than
the other, as it is also much inferior in goodness and
beauty."
AUSTRALIAN MINES.
Several mines have been worked in this great island,
in a district not very far distant from Adelaide. The
most celebrated of these is the Burra-Burra mine.
The vein occurs in a rock corresponding with the kil-
las of Cornwall, and contains the green carbonate and
the red oxide of copper. So productive is the mine,
that, notwithstanding its distance from Adelaide, (eighty
six miles,) the badness of the road, the want of wood
for timbering the mine and smelting the ore, very large
profits have been made. The mine was opened in Sep-
tember, 1845. Up to January, 1850, only <6 had been
paid in on each share, yet the stock was quoted at <157.
In March, 1853, a dividend of 5 per share on 2464
shares, was paid. The whole amount of dividends paid
from the opening of the mine to that date was X135 per
share. In August, 1851, the discovery of gold was
made and the miners were all attracted to the deposits
of the more valuable metal. The produce of the six
months, ending on September 30th of that year, was
10,732 tons of ore, in which the profits were ,49,506.
The directors refused to declare more dividends till more
MINES OF COPPER. 209
workmen could be obtained. Since then the payment
of dividends has been resumed. The last paid was on
June 4th, 1856, amounting to <5 per share. Up to
that time the whole sum paid in dividends was =170.
Kapunda mine is next to Burra-Burra in richness.
It shipped to England in 1846 and 1847, 2768 tons of
ore, yielding from 20 to 50 per cent, of copper.
The entire amount of metallic copper furnished by
the Australian mines between the years 1844 and 1853 is
stated by Whitney to have been 19,620 tons. The
gold excitement having caused a great falling off in the
produce of copper, the mines have not yet fully recovered.
SOUTH AMERICAN MINES.
Peru. The copper ores of this country occur in two
distinct formations, in the granitic and igneous, and in
stratified rocks. In the former, whatever the nature of
the ores, they never contain silver. The latter, besides
regular silver ores and beds of argentiferous galena, also
carry silver in the copper ores.
Near Antarangra a vein is worked which furnishes
rich ores. These are smelted and yield a regulus, con-
taining 50 per cent, of pure copper, which is sent to
England to be worked. Near Colcabamba is another
furnace, smelting ores which occur in a segregated mass
in the granite. There are numerous veins of argentifer-
ous copper ores in the districts of Ninobamba and Cas-
tra Virequa, which were formerly wrought very exten-
sively by the Spaniards. Recently several companies
have been formed in Peru to resume the workings. The
amount of copper furnished by Peru is not exactly
18*
210 MINES OF COPPER.
known. Mining, like every other pursuit, is much re-
tarded by the political commotions of the country.
Chili. Domeyko divides this country into two ranges
of mountains, the Andes, and the Cordilleras of the
coast, which are made up of three formations belonging
to different geological epochs. The coast range consists
of granitic or porphyritic masses running into diorite and
greenstone. The rock found most frequently in the
neighbourhood of metallic veins is a green porphyry in
white felspar. This formation occupies the entire Paci-
fic coast and extends as far in the interior as the east-
ern slope of the Cordilleras of the coast. Here begins
a secondary stratified formation of an epoch anterior to
the upheaval of the Andes. This rests upon the first
named formation, which makes its appearance beyond
them on many points of the loftiest ridge of which it
often forms a portion of the highest peaks. The first
named formation is barren, but this contains numerous
metalliferous veins. It appears to belong to the Juras-
sic or cretaceous system. In the north, it contains cal-
careous and compact fossiliferous rocks, but to the south
these entirely disappear. Throughout they are subor-
dinate to the stratified porphyry and compact schistose
or brecceoidal rocks that form the bulk of the chain of
the Andes. This secondary formation varies in its dis-
tance from the coast and in its elevation. In the pro-
vince of Atacama, it is twenty or twenty-five miles from
the sea and has an elevation of 1500 feet ; in the south-
ern provinces it is not found within twice that distance,
nor until a great altitude is attained, sometimes near
the summits of the Andes. The tertiary beds, which
MINES OF COPPER. 211
have been deposited since the uplift, rest upon this
secondary formation.
The gold veins are found in the old granite masses ;
the copper devoid of silver, antimony or arsenic, among
the diorites, porphyries, sienites and other eruptive rocks
in the vicinity of the secondary formation. The chlo-
rides and native amalgams of silver are found near the
line of contact of the primary and secondary forma-
tions ; arseniates and sulpho-arseniates of copper and
silver farther east, and argentiferous sulphurets of cop-
per, sulphuret of lead, argentiferous blende and pyrites
still nearer the Andes.
The district to the north of the valley of Huasco is
very rich, especially in silver. In 1842, there were one
hundred mines of silver, four of gold, and forty of cop-
per in operation in the department of Copiapo alone. In
1850, the silver mines had increased to two hundred and
ninety, the gold to six, while those of copper had dimi-
nished to thirty.
The mines in the vicinity of Copiapo were originally
worked for gold, which was produced in great abundance
by the upper part of the vein. When that metal began
to fall off, copper took its place. In 1845, there were
fifty mines at work, producing twenty-five per cent, ore,
most of which was sent to England, though a portion
was smelted on the spot. The principal vein at Cerro
Blanco was worked for silver, the chloride of which was
found in the upper part of the vein. At a depth of two
hundred feet, both this and native silver had disap-
peared, and gray copper, rich in silver, took its place.
Lower down it passed into gray copper and galena, and
212 MINES OF COPPER.
before the miners had reached the depth of six hundred
feet, copper and iron pyrites constituted the entire con-
tents of the vein. It was then abandoned by the origi-
nal holder, and finally sold to an Englishman, who
erected furnaces on the spot, smelted the ores which
contained from twenty-five to thirty per cent, of copper,
and sent the produce through Huasco.
South of the valley of Huasco, and nearest the coast,
the most important mines are those of San Juan and
Higuera. They occur in diorite, and furnish oxide of
copper and copper pyrites. In 1845, their product ex-
ported was over 5,800 tons, besides what was smelted
in Peru. Lieutenant Gillies reports their production in
1851 to be 4,500 tons. At Los Camerones, a vein en-
closed between dioritic rocks composed of white feldspar
and black amphibole, crops out on the southern face for
nearly half a mile. The surface ores are carbonates,
silicates and oxides ; the deeper, copper pyrites and eru-
bescite. The gangues of the oxides are argillaceous
and ferruginous, containing micaceous iron ; while those
of the sulphurets are quartzose, containing much tremo-
lite. This is an old mine, and at one time produced
ores of fifty per cent. At present, it is worked by an
English company, who take out 1200 tons a year,
averaging from fifteen to twenty per cent. Those which
yield more than twenty-four per cent, are shipped to
England; those of seven and eight per cent, are rejected,
and the rest are smelted on the spot in reverberatory
furnaces, the fuel used in which consists of arborescent
cacti and branches of shrubs. The department of Co-
quimbo is also abundantly supplied with copper ores.
MINES OF COPPER. 213
A large amount of this copper is smelted on the coast
and sent off either as regulus or as pig copper, though
some of it is worked up into sheathing and sold at
Valparaiso.
Argentine Republic. Some valuable ores of copper
have been discovered in the Maldonado mountains. They
are native copper, red oxide of copper, and erubescite.
MINES OF THE WEST INDIA ISLANDS.
Jamaica. Several English companies are now engaged
in working the mines of this island, some of which pro-
mise very well. The stratified rocks of this island belong
to the Silurian age, but there are large areas of por-
phyry, granite, trap, greenstone, gneiss and chlorite
slate.
The mines are not yet fully developed, and our infor-
mation concerning them is scanty. The Clarendon
Consols, in Clarendon Parish, has a large lode, fre-
quently disturbed, composed of porphyry and siliceous
matter with spots of yellow ore. It is hard, and as yet
has been very little worked. The capital is .80,000.
Wheal Jamaica, or Charing Cross Mine, in the same
parish, is in the south-east flank of the same mountain
which contains the last-named mine. The lode is four
or five feet wide, underlying from ten to twelve inches
in the fathom. The mountain, rising to a height of
eight hundred feet above the valley, affords a good
opportunity for cutting adits, which have been driven at
distances of twelve or thirteen fathoms apart. The
upper levels are ferruginous, but free from gossan at a
moderate depth below the surface. The veinstone is
214 MINES OF COPPER.
quartyose, carrying, in the fifty-eight fathom level, yel-
low pyrites and a little gray ore, mixed with carbonates
and silicates. The ore is found in branches, some of
which are a foot in width. The surrounding rocks are
porphryites. The nominal capital is ,100,000; though
there had been issued, up to the date of the last report
which we have seen, but 35,000 shares of <! each, on
25,000 of which 12s. had been paid in.
On the west side of the Liguanian mountains, a range
of limestone hills two thousand or three thousand feet
high, at Mt. Salust, there are seams of crystalline garnet
rock carrying yellow copper. Simpson s lode, five feet
wide, is composed of granite carrying yellow ore.
Cuba. Formerly the mines on this island were con-
sidered very valuable, and did actually produce large
quantities of excellent ore. A few years ago, they fell
off their yield, but seem to be at present rising again in
importance. The ores are not believed to be in regular
veins, but in beds and masses, subordinate to igneous
rocks, especially greenstone and serpentine. The gangues
are chiefly quartz, but sometimes limestone. The prin-
cipal ore is the yellow sulphuret or copper pyrites,
which is occasionally mixed with hydrated oxide of iron ;
while near the surface, are found carbonates, oxides and
silicates. Some very remarkable ores have been sent
in from this island. From the neighborhood of St. Jago
we have received a black ore, in great masses, averaging
about ten per cent., containing scarcely any gangue,
but composed almost entirely of iron pyrites and covel-
line, or indigo-copper. A yellow copper sand, as light
as flour, but containing thirty per cent, of copper, has
also been sent in.
MINES OF COPPER. 215
There are two principal companies, both English, now
at work on the island. The Cope mines, or the consoli-
dated mines of the Cope association, are the most
important. They have been successfully worked since
1834. Their product has fluctuated considerably since
1836, the highest annual yield being 22,741 tons, and
the lowest 2,077. The average for ten years, ending in
1849, was nearly 19,000 tons. For the quarter ending
September 30th, 1856, this company sold in Swansea,
3,529 tons of ore for 52,325 11s., while all the other
sales of Cuba ore amounted to 467 tons at .26,092 11s.
The Royal Santiago Mining Company was formed in
1837, and has 17,000 shares, on each of which 13 was
paid in. From 1840 to 1845, 55,540 tons of ore were
raised, at a cost of 247,043, or about $22 per ton.
They brought $557,533, thus yielding a clear profit of
48 per ton. Up to 1848, 33 4s. had been paid in
dividends, but since then, the mine has been worked
at a loss. In 1853, an assessment was levied on the
shares.
COPPER MINES IN THE UNITED STATES.
In describing the valuable deposits of this mineral
which occur in this country ; the arrangement of Whit-
ney will be adopted. He describes the American mines
under three heads, I. the Lake Superior Region, II.
Copper deposits of the Mississippi Valley, and III. Cu-
priferous deposits of the Atlantic States. The latter he
divides into three groups.
1. " Copper-bearing veins of the Appalachian chain, in
rocks of the metamorphic palaeozoic age ; ores chiefly
216 MINES OF COPPER.
pyritons ; deposits mostly in the form of segregated
veins ; localities numerous extending along the flanks of
the great Appalachian chain, from Vermont to Tennes-
see worked in numerous places.
" 2. Deposits in the sandstones and associated trap-
pean rocks, of the formation commonly called the New
Red Sandstone ; ores, carbonate, oxide and native cop-
per, principally ; contact deposits, usually of limited
depth. Localities numerous in Connecticut and New
Jersey; formerly extensively worked, but now abandoned.
" 3. Veins traversing the new red sandsone and older
metamorphic rocks, and bearing principally ores of
copper in the sandstone. Locality confined to Montgo-
mery and Chester Counties, Pennsylvania, and these
extensively worked."
COPPER REGION OF LAKE SUPERIOR.
Attention was very early called to the remarkable
deposits of native copper upon the shores of this great
lake. The first mention of it appears to have been in
the Missionary Reports of the Society of Jesus, for
1659-60. It is next spoken of by Claude Allouez, a
Jesuit missionary, who visited this region in 1666. He
speaks of having seen pieces of copper of ten or twenty
pounds weight, which the savages reverenced as house-
hold gods, and of having passed the site of a great rock
of copper, then buried in sand. In the Reports for
1669-70, Father Dablon reports a marvelous story,*
* They said that a party visited the Island, and in cooking their
meals, observed that the stoves they used to heat the water were
nearly all copper. They took plates of copper with them, and as they
MINES OF COPPER. 217
which was told him by the Indians, concerning a copper
island about fifty leagues from the Saut, which he inter-
prets as a cause of poisoning from the metal, loose
pieces of which the savages used in cooking their meat.
Charlevoix, whose travels were published in 1744, cor-
roborates these accounts, and mentions the fact that a
brother of the order made chandeliers, crosses and
censers of the copper which was there found.
About 1763, a practical Englishman, Alexander Henry,
passed through this region. He narrowly escaped being
massacred by the Indians, but in spite of his trouble
he kept his eyes open to his own interest. In 1771, he
commenced mining operations in the clay bluffs, near
the forks of the Ontonagon river. The following year
he transferred his workmen to the vein on the north
shore, but being discouraged by the contraction of the
lode from four feet to four inches, he became disgusted
and finally abandoned his workings.
In 1819, General Cass and Mr. H. R. Schoolcraft
passed through this region and visited the famous mass
of native copper on the Ontonagon. In 1823, Major
Long and his party saw the scattered boulders of this
formation. Nothing, however, came of all these obser-<
vations, the general impression being that the wildness
of the country and its distance from setlements ren-
dered these enormous natural resources valueless, at
at least for many years.
were pushing off from the shore, they heard a voice exclaiming, " Who
are the thieves that carry off the cradles and toys of my children ?"
The whole party died, one shortly after reaching home, the others on
their voyage.
19
218 MINES OF COPPER.
The first impulse to mining in this district was given
by Dr. Douglass Houghton, state geologist of Michigan,
who, in 1841, in his annual report to the Legislature,
gave an account of the geology of the country, and the
first scientific description of the copper deposits. Sub-
sequently, he devised an admirable plan for developing
the resources of this region, and had commenced carry-
ing it into practice when his sudden death by drowning
put a stop to these important observations.
In 1843 was ratified with the Chippewas a treaty,
which put the United States in possession of the terri-
tory as far west as the Montreal river and southerly to
the boundary of Wisconsin. The same year numbers of
persons entered land in this neighborhood, by the provi-
sions of a joint resolution of Congress in reference to
the "lead lands" of Illinois, passed as far back as 1818.
At first the applicant was allowed to select a tract three
miles square, but afterwards he was limited to one mile
square. He was required to make selection within a
year, to mark the corners, to leave a person in charge
to point out the bounds and to transmit to the proper
department a description and plat of the same. On the
^receipt of this plat, the applicant was entitled to a lease
of three years, renewable for three additional years, on
condition that he should work the mines with due dili-
gence and skill, and pay the federal government six per
cent, of all the ores raised.
As a natural consequence of these liberal provisions,
a great influx of speculators and their agents took place
into this territory. The first mining operations were
commenced in 1844. Masses of native copper
MINES OF COPPER. 219
containing silver were found, and numerous veins were
discovered. About a thousand permits were granted by
the department, and nine hundred and sixty-one sites
selected. Sixty leases for tracts three miles square,
and one hundred and seventeen for tracts one mile
square, were granted, and mining companies were or-
ganized under them. " Most of the tracts covered by
these were taken at random, and without any explora-
tions whatever ; indeed, a large portion of them were on
rocks which do not contain any metalliferous veins at
all, or in which the veins, when they do occur, are not
found to be productive." The excitement reached its
height in 1846. Quantities of stock were sold which'
represented no value whatever, and this reckless specu-
lation injured the reputation of the mines.
In 184T, the country was almost deserted, only about
half a dozen companies, out of all that had been formed,
being engaged in mining.
In 1846, further grants of land were suspended as
illegal, the resolution in regard to lead not covering
" copper lands, and the following year congress passed an
act authorizing the sale of the lands and a geological
survey. For the latter purpose, Dr. Charles T. Jack-
son was appointed, but after having spent two seasons
in these explorations, he resigned, whereupon the work
was confided to Messrs. Foster & Whitney, who have
given a very full and satisfactory account of the geology
of the country and its prospects as a mining region.
Meanwhile, the actual miners had made considerable
progress in their excavations, and as they purchased
lands after thorough examination, confidence was gradu-
220 MINES OF COPPER.
ally restored. By the time the United States Survey
had been completed and its results published, in 1850,
copper mining had become an established business.
The report of Foster & Whitney contains some very in-
teresting details of the discovery of ancient excavations
for mining purposes. Some of these are quite extensive,
reaching the depth of fifty feet, and containing rude
implements for boiling water, stone hammers, copper
gads and other mining tools. It would appear, from
some of the indications, that fire was the agent used to
disintegrate the rock. Some idea of the extent of their
operations may be formed from the fact that one of the
explorers found a mass of native copper, weighing six
tons, which had been detached by these ancient miners
and supported on billets of oak, preparatory to removal.
The age of these works may be inferred from that of a
pine-tree stump growing out of one of the mounds of
rubbish from the mine. This contained three hundred
and ninty-five annual rings, so that the exploration must
have been made before Columbus started from Europe
on his memorable voyage of discovery.
A rapid survey of the geology of this region forms a
necessary prelude to any remarks upon its metalliferous
veins. In this we follow Mr. Whitney.
Lake Superior lies in a basin of sandstone, belonging
to the lower Silurian system, and believed to be the
equivalent of the Potsdam sandstone, hitherto supposed
to be the lowest fossiliferous rock in this country. The
strata, on both sides, dip towards the centre of the lake.
Going southward from any point between Saut Ste.
Marie and the Pictured Rocks, the traveller passes over
MINES OF COPPER. 221
the upper members of the Silurian system, successively
cropping out above the sandstone, with a slight southerly
dip. Here the sandstone rock lies nearly horizontally,
is coarse-grained, and but little coherent. Its whole
thickness does not appear to exceed 300 or 400 feet.
Where it comes in contact with the older azoic rocks, at
about the Carp and Chocolate rivers, it rests unconform-
ably upon them, being deposited nearly horizontally on
their upturned edges. At Keweenaw Point, a peninsula
extending from the southern shore, in a northeasterly
direction for nearly seventy miles, the character of the
rock changes. It becomes thicker, is tilted at a consid-
erable angle, and is associated with great beds of con-
glomerate and trappean rock.
If this line of upheaval of trap be traced, it will be
found to consist of a series of parallel ridges, usually
two in number, but sometimes three or more, extending
in a southwesterly direction along the whole line of the
lake, at a distance of a few miles from it, gradually
diminishing in elevation as they traverse Wisconsin, and
disappearing before they reach the Mississippi. Their
average height above the lake is 500 feet. Towards
the south they present steep mural faces, while they dip
at a moderate angle towards the north. This line, com-
monly known as the "Trap Range," for 120 miles in
length and 26 in width, is metalliferous, along it occur
the copper mines of the southern shore of Lake Supe-
rior.
The rocks of this range are various in character, but
most of them are manifestly igneous, and are supposed
to have been poured out at the same time that the depo-
19*
222 MINES OF COPPER.
sition of the sandstone was going on. In the more ele-
vated and central portion of the range, igneous rocks
predominate, containing intercalated beds of conglomer-
ate, of very inconsiderable thickness, between heavy
masses of trappean rock. Upon the sides, the trap
gradually thins out, while the conglomerate thickens, till
in its turn it gives way to the sandstone. This system
of bedded trap and interstitial conglomerate is very
extensive, some of its beds acquiring a thickness of seve-
ral thousand feet.
The usual mineral constituents of the trap are labra-
dorite and augite, with a smaller proportion of other
minerals, among which the most abundant are magnetic
oxyd of iron, chlorite and epidote. The felspathic and
augitic portions form a homogeneous paste, in which
the other minerals are embedded, the difference in these
rocks arising rather from their mechanical structure than
their chemical composition. Thus on Keweenaw Point,
there are- two well-marked varieties of trap, between
which are innumerable others partaking more or less of
one or the other character. One of these is porous or
vesicular in structure, containing cavities of various
sizes, which have since the formation of the rock, been
filled with other minerals. The other is very compact
and finely crystalline. In the former or amygdaloidal
variety, provided it be not too soft or porous, is found
the largest amount of copper, the compact variety being
unproductive.
The remarkable peculiarity of this region is the enor-
mous quantity of native copper which is found in its
veins. Elsewhere, native copper has been regarded as
MINES OF COPPER. 223
rather an accidental accompaniment of other ores, but
here it constitutes the entire mass of the metallic con-
tents, and this character does not change at the greatest
depth which the workings have attained. Out of the
bedded trap, however, sulphurets make their appearance.
" Thus in the Bohemian or southern range of the Ke-
weenaw Point, which seems to have been protruded at a
late epoch, and under different conditions, and to have
tilted up the system of bedded trap and interstratified
conglomerate which lies to the north, the veins bear
only sulphuret of copper ; and on the north shore, where
the trappean rocks are most developed, they appear to
be of the same imbedded character, and they are tra-
versed by powerful veins bearing the sulphurets of cop-
per, zinc and lead."
The mines of Lake Superior are divided by Mr. Whit-
ney into four groups: 1. Keweenaw Point; 2. Isle Roy-
ale; 3. Ontonagon; 4. Portage Lake.
Keweenaw Point contains a large number of mines,
its mining region extending over a space about thirty-
six miles long by two or three broad. From its eastern
extremity a belt of metalliferous trap extends through
it, in a nearly east and west direction, gradually curv-
ing in its western prolongation towards the south. There
are two distinct ranges, the Greenstone and the South-
ern or Bohemian Range. The former comprises a line
of bluffs, rising sharply from the valleys of Eagle and
the Montreal rivers, which drain the district, rising
near its centre, and flowing through it longitudinally in
different directions. It is a compact, crystalline, homo-
geneous rock, several hundred feet thick, dipping to the
224 MINES OF COPPER.
north at an angle of twenty or thirty degrees. To the
south, its limits are well defined. It rests upon a stra-
tum of conglomerate, accompanied by a thin layer of
consolidated volcanic ash, and below this lies the great
southern metalliferous belt of Keweenaw Point. In
this, numerous mines have been opened, which always
fail in metallic contents when they are carried into the
greenstone above the conglomerate and trappean ash.
At the eastern end of the Point, this bed of conglom-
erate is thirty or forty feet thick, but it gradually thins
out, and finally disappears near the Cliff mine. The
main features of the distinction between the greenstone
and the amygdaloidal trap, however, remain. Between
the conglomerate and the greenstone, towards the west,
are occasionally found thin seams of quartz, which often
contains sheets and particles of copper.
To the south of this thin belt of conglomerate, the
amygdaloid extends for two or three miles ; but as it
lies in the low ground, it has only been explored by un-
derground workings, which have not as yet penetrated
its thickness, nor revealed the depth of the beds of which
it is composed.
North of the conglomerate, the greenstone is from a
quarter of a mile to half a mile wide, and gradually
changes to amygdaloid resembling that on the southern
side of the conglomerate. This " northern metalliferous
amygdaloid belt" is bounded to the north by the sand-
stone, varies in width from a mile to a mile and a half,
and contains several important mines, imbedded in a
variety of trappean layers. Further north is a series
of alternating belts of amygdaloid and sandstone of
MINES OF COPPER. 225
moderate thickness, varying from 50 to 500 feet; and
next to these is a belt of conglomerate, nearly a mile
wide. Beyond is another bed of amygdaloid rock, about
1500 feet thick, succeeded by conglomerate, which forms
the northern portion of the Point from its extremity as
far west as Agate Harbor.
The mines are worked, almost exclusively, in metalli-
ferous deposits which have the character of true veins.
They cross the belts of rock nearly at right angles, and
have, in many instances, been traced through all the
formations. One vein is known to have been worked on
both sides of the greenstone. The veins change charac-
ter as they pass through the different belts. In the con-
glomerate their gangues are calcareous, the copper being
usually concentrated into large masses. In one instance,
black oxyd of copper is found in the rock. Mr. Whit-
ney thinks it probable that these same veins extend
across the valley into the southern range, and there bear
sulphurets.
In the true copper-bearing rocks, the veins are made
up of quartzose rock, mixed with calcareous spar and
zeolitic mineral, of which prehnite and laumonite are
most common. The most favorable vein-stone contains
crystallized and drusy quartz mixed with prehnite and
granular carbonate of lime. In some instances the
veins are brecciated, i. e. made up of fragments of the
adjoining rock, cemented by the usual vein-stone. At
other points purely calcareous veins have been worked
in the trap, but they are now regarded as worthless,
especially when the carbonate of lime occurs in the form
of coarsely crystallized spar. Smaller veins or strings
226 MINES OF COPPER.
are made up almost entirely of laumonite, and contain
very little copper.
" The width of the productive veins is usually from
one to three feet; they sometimes widen out to ten feet
or even more, but rarely continue to hold those dimen-
sions for any considerable distance. The wider the vein,
as a general rule, the richer it is in metallic contents."
But one system of veins has been observed in this
district. They are remarkably regular in their course,
which is nearly at right angles to the bearing of the
formation. They are sometimes shifted a few feet to
one side or the other, as they pass from one belt to an-
other, but there are no regular cross-fractures or coun-
ter-lodes, such as prevail in most extensive metalliferous
districts. The parallelism of the productive lodes of
Keweenaw Point is very remarkable. They have no
tendency to unite together .
The dip is nearly vertical, the underlay, or deviation
from the perpendicular, being rarely more than eight or
ten degrees. The vein is usually separated from the
wall rock by a distinct selvage of red clay, and the walls
are striated or polished. The copper is mixed with the
vein-stone in pieces varying from the most minute specks
and strings up to masses of one to two hundred tons
weight. In accordance with the size of the pieces, the
copper is classed under three varieties, mass copper,
barrel-work and stamp-work.
Masses are sometimes met with twenty or thirty feet
in length. In such cases the rock is cleared away from
one side of the mass, and it is detached from the wall by
heavy charges of powder inserted behind it. It is then
MINES OF COPPER. 227
cut up into pieces oi convenient size for lifting through the
shaft. This is a very tedious and costly process, several
months being sometimes occupied in dividing and remov-
ing a single mass. For this purpose they employ chis-
els having a cutting edge of about the fourth of an inch
in width, and varying in length according to the thick-
ness of the mass to be divided. One man holds and
guides the chisel, while another strikes it with a heavy
sledge, so that chips are gradually taken out of a length
equal to the distance to be cut across, and a thickness
of about one-eighth of an inch. The process is repeated
till the mass is completely severed. The expense of
this operation is usually about six dollars for every
square foot of surface exposed on one side of the cut.
On reaching the surface, further subdivision is required,
in order to obtain masses convenient for shipment. As
thus prepared, the vein-stone not being entirely removed,
the mass copper contains 70 or 80 per cent, of pure
metal, though sometimes, being almost wholly free from
foreign matter, it yields from 90 to 95 per cent, when
smelted in the furnaces. This test, however, cannot be
regarded as a satisfactory one of the actual amount of
metal contained in these masses, since some of the
smelting works are conducted in the most unscientific
manner, and waste an enormous quantity of copper.
Barrel-work includes the smaller pieces, weighing
usually a few pounds. This name is given to them be-
cause they are too small to be sent away without being
previously packed in barrels. Much of this is obtained
during the preparation of the stamp-work. The pieces
are well hammered to free them from adhering vein-
228 MINES OF COPPER.
stone, and, as thus prepared, contain from 60 to 70 per
cent, of pure copper.
Stamp-work forms a large portion of the yield of all
the veins, so that each mine requires a set of stamps
containing a number of heads proportioned to its extent.
The rock is first calcined by being laid upon a pile of
wood which is then kindled. Care is taken not to melt
or oxydize the copper. The rock being thus rendered
friable, is placed under the stamps. During this process
of preparation, some pieces are met with which are too
large to be put under the stamps, and contain too much
copper to allow any further reduction in size. These are
barreled up, and the rest of the ore is placed under the
stamps, pounded, washed and packed up.
A full account of the mines in this region, beginning
on the northern metalliferous belt, is given by Mr.
Whitney, from whose valuable work we make the follow-
ing abtract, supplying the later facts from recent authen-
tic documents when we have been able to procure them.
The New York and Michigan mine was opened in
1846, and continued in 1847, till the shaft was 84 feet
deep. It was then abandoned, resumed in 1852, when
the shaft was continued. In September, 1853, having
reached a depth of 150 feet, it was finally abandoned.
A drift was run off to the north for 100 feet or or more,
and the vein was found to be, in some places, 20 inches
wide; the vein-stone being quartz and prehnite, carry-
ing a little copper. Four small masses, weighing about
1,800 Ibs. were shipped in 1852. This mine, being sit-
uated in the unproductive green-stone, could not be
worked with profit.
MINES OF COPPER. 229
The Clark Mining Company commenced operations
in the autumn of 1853, on a vein running north 10
west, a foot or eighteen inches wide, well filled with cop-
per. It has been opened at several points, and found
to be well defined and promising favorably for success-
ful working.
The Washington Mining Company has several veins
in the vicinity of Musquito Lake, but had not yet com-
menced operations at the date of Mr. Whitney's publi-
cation.
The Agate Harbor Mining Company has been explor-
ing, and has discovered many powerful veins, having a
course of about south 19 east.
Adjoining them is the "Keliher Vein," bearing north
25 west, being from two to eight feet wide, having a
brecciated vein-stone containing much copper, and
opened already over an extent of 2,500 feet.
The Eagle Harbor Mining Company has explored
this, region without success.
The Native Copper Mining Company commenced
operations in 1852. A shaft had been sunk 120 feet
and a cross-cut driven, at a depth of ten fathoms, to the
vein. The vein is wide, brecciated and unproductive.
The Copper Falls Mining Company was originally
formed in 1845. They began mining in 1846 on the
" Old Copper Falls Vein." The workings were com-
menced upon a belt of trap only 170 feet thick, measured
at right angles to the dip, arid 430 feet across on the
line of adit, inclosed between two beds of sandstone. A
shaft was sunk 53 feet through the underlying sandstone.
In the trap, the vein was rich, but on entering the
20
230 MINES OF COPPER.
sandstone, it rapidly contracted and split up so that it
was not thought advisable to follow it. The shaft alluded
to was therefore sunk and cross-cuts driven in each
direction for forty feet, without finding the vein. The
same vein has been traced on the surface, south of all
the belts of sandstone. From this mine $15,000 worth
of copper was taken, while on it $100,000 were spent.
This resulted entirely from a want of proper geological
knowledge. To remedy this defect, a competent geolo-
gist was employed, who surveyed the whole region and
and discovered several veins, two of which, the Copper
Falls and the Hill veins, have been worked. The first
was opened in December, 1850, and the second a year
later.
All these veins are nearly parallel, running north 22
to 25 west. In almost every instance they have been
traced entirely across the whole belt of trap north of the
greenstone. Upon each of these veins some shafts have
been sunk, and large quantities of copper have been
taken out. According to the report of the superinten-
dent, dated March 1st 1854, it appears that they yield
865 pounds to the fathom.
The Phoenix Mining Company is the oldest of these
organizations. It was formed in 1844, under the title
of the "Lake Superior Copper Company." By direc-
tion of Dr. C. T. Jackson, work was commenced, in Oc-
tober, 1844, on Eagle river, and carried on through the
year 1845. " A stamping mill and crushing wheels, of
a kind suitable for grinding drugs, were erected but
soon proved to be entirely unserviceable." Up to March
31, 1849, about $106,000 had been expended, "about
MINES OF COPPER. 231
half of which was probably for actual mining work."
The principal shaft was sunk upon a " pocket" of copper
and silver, without any signs of a regular vein, which
soon gave out entirely. In 1846, a drift was run off
from the shaft at a depth of ninety feet, towards the
river, to find a vein, and directly under the river the
workmen found a crevice, filled up with gravel. This
was evidently the ancient bed of the Eagle River.
Workings were carried on and a large pot-hole was found,
filled with rounded pieces of native copper and silver.
From this and other excavations, 18,000 pounds of cop-
per were taken, as well as much silver, most of which
was stolen by the miners. One piece of silver, weighing
96.8 ounces Troy, came in possession of the company.
Finally the vein was struck and sunk upon for about
ninety feet, after which work was suspended until the
Phoenix Company took charge of the property in the
autumn of 1850. This company continued operations
along the vein, which still ran under the river, until
February, 1853, when they abandoned it. The trouble
from water, especially during freshets, was so great that
it was impossible to work to any advantage and besides
that, the vein, away from the river, was too narrow for
profitable mining. The principal shaft was sunk to a
depth of about 264 feet, and three levels driven between
500 and 600 feet. The vein-stone consisted of calc-spar
with jasper and argillaceous matter and contained copper
in fine particles and masses, some of which weighed
1200 pounds, together with silver.
In June, 1853, a thorough examination of the pro-
perty was commenced, and finished in 1854. From
232 MINES OF COPPER.
Samuel W. Hill's report, dated January 5th, 1855, the
following particulars are taken.
The property of the company is 1701 acres, having
in its northwest part, the port of Eagle river. The land
declines towards the Lake, its altitude rarely exceeding
550 feet above the level of the water, and averaging not
more than 350 feet. The banks of Eagle river, (which
runs through it,) vary in elevation, being, in some places
high and precipitous, in others low and easily accessi-
ble.
The band of rock near the lake is conglomerate. It
is succeeded to the southward by alternating beds of sand-
stone and trap, having a dip of 25 towards the lake.
Below these are various beds of trap terminated by a
hard, light blue columnar trap. Underneath this is a bed
which is composed mostly of an ash, thin bands of trap
and sand stone, and rounded scoriaceous bodies of trap or
lava. This mass is cupriferous and between it and the
stratum last named a slide has taken place. In some
places the dislocation has been sufficiently great to pro-
duce open spaces between the walls, which have been
filled up with vein-minerals. There are ancient excava-
tions in this bed, and it is in some places well filled with
copper. Below this is a greenish gray trap in which the
principal excavations of the old mine were made. This
is succeeded by several beds of trap, followed by a belt
of crystalline trap or greenstone, the veins traversing
which are well filled with copper. After this come sev-
eral beds of trap, ending in a soft porous band, which
overlies the series of dark colored, close-grained trap
layers in which the Cliff mine is worked. After these
MINES OF COPPER. 233
comes a columnar trap, poor in copper, and then an
amygdaloid which promises well for that metal.
These beds do not all contain copper. As elsewhere
in this region, there are distinct metalliferous zones.
The chief of these is the series worked in the Cliff mine.
Next in importance is the ash or scoriaceous bed, which
was at first thought remarkable for having the copper
diffused through the rock and not in a vein. Subse-
quently, however, it has been stated that this scoriaceous
bed is a true east and west vein.
There are several veins on this property, the Ward
vein, the Forster vein, the Armstrong vein, the East
Phoenix vein and several others which have not been
named. The workings already described were upon the
old Phoenix vein. Attempts were made to renew work
on this vein in 1855, but finally discontinued on account
of the old trouble with water. The Armstrong vein
was worked in 1851 and 1852, but was found to be poor
in copper. The East Phcenix vein was discovered in
1852 and the following season, a mass, weighing 2,390
pounds, was taken out quite near the surface. In 1855,
the principal working was on the "ash bed." About
five tons were sent to Boston in November of that year,
and smelted at the Revere Works. The metal was found
to contain a large amount of silver, the poorest speci-
mens being reported as worth $100 a ton for that metal.
The prospects of the company are now good.
The entire amount expended here cannot be much
short of $200,000, and there are few places upon Lake
Superior which show more abundant indications of cop-
per.
20*
234 MINES OF COPPER.
The mines on the southern side of the greenstone
bluffs are very well situated for working. They have
never been opened to any extent in the greenstone, but
close to the conglomerate belt which divides the amyg-
daloid from that rock, they are as productive as any-
where else. In the neighborhood of the Cliff mine the
position is less favorable for adit draining. Towards
the eastern extremity of the Point, the amygdaloid rises
sufficiently to give from one to two hundred feet of back
above the adit level. Frequently the productive rock is
so covered with drift that the veins can only be discov-
ered by tracing them down from the greenstone and
opening shode pits on their supposed course. This is
the reason why so many ineffectual attempts were made
to find productive veins in the greenstone and other
more exposed rocks.
The Keweenaw Point Copper and Silver Mining
Company was formed in England, and has discovered
four or five veins, but has not worked them yet to any
extent.
The Star Mining Company has sunk several shafts
and abandoned them. During the summer of 1853,
they discovered a new vein, which is said to promise
well.
The Manitou Mining Company commenced opera-
tions in 1852. They have two veins, neither of them
large nor very productive.
The Iron City Mining Company deserves notice here
as a warning to future speculators on the minerals in
this region. They have a wide and regular vein- of cal-
careous spar, cleaving into large rhombohedra, and con-
taining no copper. This kind of vein, when unaccom-
MINES OF COPPER. 235
panied by quartz and the zeolitic minerals, is always
barren in the Lake Superior mining region.
The Northwest Mining Company of Michigan, being
one of the most extensive, demands the special examina-
tion of those who are interested in the mineral develop-
ments of this district. In 1849, it took the place of a
company which had been mining in a small way since
1847. They have three veins, the Stoutenburgh, Kelly
and Hogan veins. The first contains the principal mine,
and has a course of north 16J east. The Hogan runs
north 19 west, and the two would, consequently, inter-
sect about 320 feet south of the mouth of the adit level on
the Stoutenburgh. The third or Kelly vein has a course
nearly parallel with that of the Hogan, but is not very
well defined.
The first named vein has been opened by four shafts,
the engine shaft being 500 feet deep. The longest level
driven is about 1,000 feet. The whole amount exca-
vated by sinking shafts is 1,130 feet; by driving levels,
5,450 feet; and the number of fathoms stoped is about
2,780. The vein is from six to eighteen inches wide,
the average width being about a foot. The lode consists
of clayey and sandy matter, with occasional strings of
calc spar, and does not look very promising. It contains
but .a small amount of stamp-work and that of a poor
quality, but masses, weighing from a few hundred pounds
up to several tons are frequently met with. One of
eleven tons weight was taken from the twenty fathom
level. A great deal of that which is taken from the
shaft is amygdaloidal trap containing shot copper; and
it is worthy of remark that the rock in the vicinity of
the vein is often richer in metal than the lode itself.
236 MINES OF COPPER.
The large masses appear to make outside of the lode
but close to it, impoverishing it for some distance in
every direction.
The works on the Hogan vein are much less extensive,
but the vein is more promising, containing less argilla-
ceous matter and being more crystalline. It has produced
small masses and barrel-work as well as stamp-work.
This company is the only one that has kept accurate
and reliable accounts of the produce of the stamps and
the expenditures per ton. From this report, it appears
that the average percentage of the rock when carried to
the stamps is 1.34 of copper, so that a ton contains 27.4
pounds of copper. The entire cost of working, after
the ground has been opened for stoping, is 4.42 per
ton, and the value of a ton, after deducting expenses of
transportation, is $6.97. Hitherto, however, the re-
ceipts of the mine have fallen short of its expenditures.
The value of copper exported has lately averaged over
$53,000 per annum, and the expenses $77,000.
We believe that this mine has now suspended opera-
tions.
The Waterbury Mining Company is another example
of failure in consequence of want of knowledge of the
laws which regulate the metallic deposits of Lake
Superior. It was opened in a chloritic mass interposed
between the conglomerate and the greenstone, and the
contact of these last named rocks has never been found
to yield copper in this region.
The North Western Mining Company of Detroit, works
the same vein which on the opposite side of the crystal-
line trap is known as Copper Falls Vein. Its gangue
is quartzose and chloritic, containing crystals of analcime
MINES OF COPPER. 237
and of reddish feldspar. Its average width is three feet.
In the ten fathom level, a mass of copper twelve feet
long and three feet high has been discovered.
The Cliff Mine * is the most famous of all the work-
ings on Lake Superior, being, indeed, the first mine in
the United States, excepting those of coal and iron,
which was extensively and systematically wrought. It
is also the first mine ever opened in the world upon a
vein bearing copper exclusively in the native state.
In 1843 a Mr. Raymond obtained several leases in
this region, three of which he conveyed to parties in
Pittsburg and Boston, who commenced mining in the
summer of 1844. The first work was done in the autumn
of 1844, upon the outcrop of a cupriferous vein at Cop-
per Harbor, known to the voyageurs as the "green
rock." On clearing away on the opposite side of the
harbor, where Fort Wilkins now stands, numerous boul-
ders of black oxyd of copper were found, evidently be-
longing to a vein near at hand, which was discovered in
December, and proved to be a continuation of that
worked during the summer.
Mining was commenced here immediately; two shafts
were sunk 100 feet apart, and a goodly quantity of
black oxyd of copper, mixed with silicate, was taken out.
This' was remarkable, as being the only known instance
of a vein containing this as the principal ore. Unfor-
tunately, this was but a rich bunch, which gave out at
the depth of a few feet, although the vein continued.
The gangue was chiefly calcareous spar, mixed with
some argillaceous and quartzose matter. Fine crystals
of analcime, as well as of native copper and the red
* Owned by the Pittsburg and Boston Mining Company.
238 MINES OF COPPER.
oxyd were found in it. About 30 or 40 tons of black
oxyd were obtained and sold for $4,500. The main
shaft was continued down 120 feet and levels driven
each way, for a considerable distance, without finding
another bunch of ore, so that in 1845 the company
determined to explore their extensive property. In
August, of that year, the Cliff Vein was discovered.
This vein was first observed on the summit and face
of a bluff of crystalline trap, rising nearly 200 feet
above the valley of Eagle River. The break or depres-
sion made by it in the back of the ridge was quite dis-
tinct, and has since been traced to the lake, and found
marked by ancient excavations. At the summit of the
bluff, it appeared to be a few inches wide, and contained
native copper and specks of silver incrusted with capil-
lary red oxyd. Half way down the cliff it had expanded
to a width of over two feet, and consisted of numerous
bunches of laumonite, with a small per centage of copper
finely disseminated through it.
As the vein appeared to widen in its descent, by the
direction of Mr. Whitney a shaft was sunk a few feet a
little below the edge of the bluff, and a level driven into
the greenstone for a short distance. Nothing of impor-
tance, however, was done till the talus at the base of the
cliff was cleared away, and the vein traced into the
amygdaloid. A level was then driven in upon it, and
at a distance of 70 feet the first mass of copper was
struck. '
The beds of the rock dip at about 66 to the north,
so that the extent of the mine in that direction, the
vein being opened to the south of the greenstone, is
continually increasing as each successive level is opened.
MINES OP COPPER. 239
To the south, the mine is limited by the extent of the
company's property. The longest level, 244 feet below
the adit had been extended at the date of Whitney's de-
scription, 600 feet to the south of the lower shaft, and
the supposed distance to the greenstone is 900 feet.
Each level extends in this direction about 100 feet fur-
ther than the one 66 feet above.
The mine was formerly worked through two shafts,
less than 100 feet apart; but during the winter of
1853-4, a third had been sunk to level No. 1, from the
upper edge of the bluff, a distance of 138 feet. The
engine-shaft, in 1854, had reached the ninth level, a
depth of 444 feet below the adit, and the entire depth
from the collar of the third shaft to the ninth level will
be 630 feet.
" The remarkable and uniform richness of the vein
may be inferred from the fact that no part of it is so
poor as not to be worth taking down ; and so far as the
work has been carried, hardly a fathom of ground has
been left standing on it. On calculating the number of
fathoms of the vein removed in the drifts, shafts and
stopes, I find it to be, approximately, 8,270; and there
has been produced an average amount of 761 pounds of
copper per fathom a result which is truly astonishing,
when' it is considered that the whole of the vein has
been taken down."*
It runs about north 27 west, and its underlay is about
10 to the east, but in its lower levels the dip varies
somewhat. In some places it is three or four feet wide,
in others, only a few inches; its average width is, prob-
ably from fifteen to eighteen inches. The vein-stone is
* Whitney's metallic wealth of the United States.
240 MINES OF COPPER.
quartz, calcareous spar, and the zeolitic minerals, and
it abounds in fine crystallizations.
Its metallic contents are exclusively native copper
and silver. The copper occurs in masses of great size,
from a few hundred pounds up to nearly a hundred tons ;
and the vein is not only rich in these, but also furnishes
a large quantity of stamp-work, containing an unusually
high per centage of copper.
At the date of the last report, shaft No. 4, had
reached a depth of 251 feet. The second shaft was
sinking from the 70 to the 80 fathom level, at which it was
expected to cut the vein. The extension of this shaft
will be much deeper, if the productive stratum recently
discovered at the North American mine be sought for.
This will not be reached at a less depth than 950 feet
from the adit level.
Besides this main vein, and its droppers, there are
several others on the property. The west vein, which
was formerly supposed to be a mere divergence of the
old vein, upon one of its numerous floors of amygdaloid,
has been found to be a distinct and separate lode, very rich
in copper. The East Cliff vein, about 40 rods east of the
present workings has been opened and seems to promise
well. About 270 feet west of the main vein, there are
surface indications of a very large lode, measuring from
four to five feet in width. It is intended to open this
by a cross cut from the 30 fathom level.
The operations of this mine will be seen by the fol-
lowing table, compiled from Whitney's book, and the
printed reports of the Directors, the original amount of
capital stock paid in by the Shareholders being only
$110,905,00.
MINES OF COPPER.
241
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21
242 MINES OP COPPER.
The amount of silver taken out varies. It is always
found in pockets, and never alloyed, to any extent, with
the copper, even at the point of contact. The most
usual mineral, accompanying the silver, is a greenish
magnesian substance, apparently talc. In the Hill vein,
a small quantity is found in the smelted copper a few
ounces to the ton not enough to justify its separation.
At the Cliff mine, the largest quantity of this metal ob-
tained in one year was nearly 35 pounds troy. It is
picked out by hand from the coarse metal which is taken
from under the stamp-heads.
The North American is another old company, and has
mined extensively at two points. The "Old North
American Mine" was opened in 1846, and worked till
the spring of 1853, when it had reached the depth of
415 feet. The course of the principal vein is north 58
west, and, therefore, not parallel with the productive
veins of the formation. During the four last years it
was worked, it yielded 446,000 pounds of pure copper.
The entire expenditures upon it were $ 200,000.
In 1852 this company opened the South Cliff mine,
on an extension of the famous Cliff vein. Up to Feb-
ruary of 1854, 715 feet had been opened in driving, 76
feet in cross-cutting, 438 feet in sinking in rock, and
106 fathoms had been stoped. From these workings
the extraordinary amount of 506,000 pounds had been
taken, yielding an average of 67| per cent, of copper.
At this mine, on the 4th of July, 1853, was thrown
down the largest mass of native copper ever before found
on Lake Superior. It was 40 feet long, 20 high, and 2
thick. Its weight was estimated at from 150 to 200
tons.
MINES OF COPPER. 243
The vein-stone of this mine, near the surface, furnished
fine specimens of prehnite with crystallized copper.
Its workings extend further south of the green-stone
than those of any other mine of the region. At first the
vein seemed to he impoverished in that direction, hut as
they advanced further, it began to improve.
The Albion Mining Company sunk a shaft on this
point, in the same geological position as the Cliff Mine,
to the depth of 200 feet, but finally abandoned their
work for want of encouragement, in 1852.
The Fulton Mining Company commenced operations
on an old working in 1853, and have taken out a great
deal of copper. In one part of the mine, the vein
yielded a ton of copper to the fathom. The vein-stone
is remarkable for containing much epidote, mixed with
calcareous spar.
In addition to the veins already explored or worked
by companies, there have been others discovered upon
this point. They are held by individuals, and have
only been opened for exploration.
The geological character of ISLE ROYALE resembles
that of Keweenaw Point. The ridges of trap traverse
the island longitudinally, and this rock, with its intercal-
ated conglomerate, forms the entire island. The strata
dip in a direction opposite those on the point, and their
mural faces look towards the north. The beds, however,
differ from those in being thinner, so that the metallifer-
ous veins are subject to frequent changes in passing
from one stratum to another. Great hopes were formed
of this island at the opening of the Lake Superior region,
and soon afterwards nearly all of it had been taken up
by different companies.
244 MINES OF COPPER.
The veins are differently situated with regard to the
strata, some being at right angles and some parallel to
their dip. Epidote belts, filled with fine particles of
native copper, are found here, but they have not been
found sufficiently persistent in metalliferous contents to
be profitably worked. In 1853, nearly all the mines
were abandoned, only two being wrought and those on a
small scale.
The Siskawit Mine has been extensively worked, and
was at first quite productive. On sinking but a short
distance, however, a hard basaltic rock was encountered,
in which the vein contracted to a mere fissure. After
traversing this, the vein improved, but not sufficiently
to pay for working it, especially as it was necessary to
carry the workings under the lake, since the rocks dip
in that direction.
The Pittslurg and Isle Royale Mining Company has
worked a narrow vein rich in copper, which traverses a
crystalline rock. Their machinery is " miserably de-
fective," and their operations consequently impeded.
The ONTONAGON MINING DISTRICT receives its name
from the principal river which drains it. This stream
has three branches, one coming from the east, another
from the west, and the third from the south. Uniting,
they cross the Trap Range at right angles to its course.
The mines are on the range, and are worked at va-
rious points for a distance of twelve miles on each side
of the river, making the entire length of the district
about twenty-four miles. The cupriferous deposits here
differ from those on Keweenaw Point in their being
parallel to the line of strike of the formation.
The character of the trappean rocks also differs from
MINES OF COPPER. 245
that which they exhibit upon the point. The varieties
of rock are more numerous and epidote almost always
occurs where copper is found. West of the Ontonagon, a
large part of the range on the north is made up of reddish
quartzose porphyry, which appears to be entirely barren
of copper. The layers of conglomerate are imbedded
in the trap, and to the north it is flanked by heavy beds
of this rock. There is no marked belt of unproductive
crystalline rock here, and the position of the bed and
veins, with regard to any fixed line of upheaval, is not
so well ascertained. Copper is abundantly diffused
through the district, but mining is not so profitable here
on account of there being less concentration of the metal
in limited spaces.
The copper occurs in four forms of deposite : 1. Indis-
criminately scattered through the beds of trap. 2. In
contact deposits between the trap and sandstone or con-
glomerate. 3. In seams and courses parallel with the
bedding of the rock, and having the nature of segregated
veins. 4. In true veins coinciding in direction with the
beds of rock, but dipping at a different and usually a
greater angle, in the same direction as the formation.
Deposits of the first class are common, and have
been- worked but with poor success. Masses of many
hundred pounds weight have been repeatedly found in
the trap, without any connection with a vein fissure,
and sometimes unaccompanied by vein-stone. When
smaller, the particles of metal usually fill amygdules in
the rock, and are most abundant along the line of junc-
tion of two beds of different character.
Contact deposits have produced well in this district,
21*
246 MINES OF COPPER.
though further working is requisite to test their perma-
nent value. When they occur between the sandstone
and the trap, they are not worth much, as they soon lose
their metallic contents. The deposits which are found
between the trap and the conglomerate appear to belong
to this class, but have some of the features of true veins.
In this position great masses of copper are accumulated
near the surface, and even at considerable depths
below it.
The third class of deposit, in segregated veins, is
peculiar to this district. Occasionally the vein is irreg-
ular in its course, being suddenly heaved to one side or
the other, or disappearing altogether. In these cases,
the metallic matter seems to be accumulated in parallel
courses, coinciding with the bedding of the rocks, but
irregular in the extent and distribution of their metallic
and mineral contents. Sometimes they run into each
other, both horizontally and vertically, giving rise to
the so-called feeder veins; frequently they diminish to a
mere seam destitute of both veins and metal, and on
cross-cutting another seam is struck, often well filled
with copper.
The true veins are not numerous. They coincide
with the line of bearing of the rocks, but in following
them down, they are found to be wholly independent.
They are often rich in copper, and may be confidently
worked.
The Douglass Houghton Mine was worked on a small
scale in 1846, but it was not till 1850 that it was prose-
cuted with any energy. The vein at the surface was
between two and three feet wide, quartzose, and well filled
MINES OF COPPER. 247
with copper. There it had well defined walls with sel-
vages of argillaceous matter, and a gangue distinct from
the rock. On descending, however, it was found to be
irregular, in some places wide and well charged with cop-
per, in others entirely lost. There is a break or fault
which has displaced it fourteen feet. In the winter of
1853-4, the vein had widened again.
The Toltec Consolidated Mine was opened in 1850,
and up to March, the deepest shaft had been sunk 210
feet. Two levels have been driven and several cross-cuts
made. A mass of a ton weight has been discovered, but
the distribution of metal in the vein is so irregular that
no conclusion can be formed as to the probable success
of the mine.
The Aztec Mining Company have been carrying on
excavations in the face of a bluff, which had been very
extensively worked over by ancient miners. The copper
is scattered indiscriminately through the rock, in lumps
and small masses. In 1853 operations were suspended.
The Bohemian Mining Company works on what is
called the "Piscataqua location." It is difficult to trace
any regular vein here, but there is an epidote seam which
is rich in copper.
The Adventure Mining Company has made many
extensive but irregular excavations in the face of a bluff,
in which there is no regular vein. It is a crystalline
and compact trap having copper and silver scattered
through it. In spite of the irregularity of the workings,
a considerable quantity of copper has been taken out.
The Minnesota Mine is the most productive on the
Ontonagon, and second only to the famous Cliff Vein.
248 MINES OF COPPER.
It was discovered in the winter of 1847-8, and found to
contain excavations of the ancient miners, who had sep-
arated a mass of copper, weighing over six tons, and
then abandoned it as too bulky for removal by the means
at their command, leaving their stone hammers behind
them.
Eight principal shafts have been opened on the vein
and the South Lode, following its dip, which varies 52 to
64 to the north, that of the rocks being 44 in the
same direction. The gangue is quartz, calcareous spar
and epidote, and the walls well defined, although in some
places not very regular. They are usually smooth,
sometimes striated, but generally destitute of selvages
and flucan. Near the walls, thin lenticular sheets of
mixed calcareous spar and laumonite are frequently
found overlapping one another.
The last printed report (March 1st, 1856,) states
that, during the year, the shafts had been sunk in the
aggregate 308 feet, and winzes to the amount of 418
feet opened, making the total depth of sinking in shafts
and winzes on January 1st, 1856, 2516 feet. The
deepest shaft, No. 2, had at that time reached the 60
fathom level, 447 feet from the surface. The extent of
drifting for the same period was 3022 feet, the whole
extent of the six levels on January 1st, being 10,728
feet. The longest level (No. 1) had been opened 1663
feet, the shortest (No. 5) 436 feet. These openings ex-
posed about 117,642 superficial square feet of vein, on
which the amount of stoping done was 15,912 feet, pro-
ducing 890 Ibs. of mineral per fathom, or about 148 Ibs.
per foot, stope measure.
MINES OF COPPER.
249
The whole extent of real estate owned by the com-
pany at that time (including 115 acres in suit between
them and the National Mining Company,) was 2270
acres. During the year 1855, several masses were
taken out, one of which weighing 5,738 Ibs., was sent
to England as a mineral curiosity. In the summer of
that year, a mass of copper was exposed in the 10
fathom level near No. 5 shaft. In February, 1856, the
agent reports that 27 men were constantly employed
upon it, and that 200 tons of copper had been taken
from it, but that they had not yet been able to deter-
mine its extent.
The following table is copied from the same report.
Date.
No. of men
employed.
Expendi-
ture.
Mineral
product.
Tons.
Nett value
in copper.
Assessra'ts
paid.
Dividends
paid.
1848,
20
$14,000
6*
$1,700
$10,500
1849,
60
28,000
52 14,000
16,500
1850,
90
58,000
103
29,000
36,000
1851,
175
88,000
307
90,000
3,000
1852,
212
108,000
520
196,000
$30,000
1853,
280
168,000
523
210,000
60,000
1854,
392
218,000
763 ; 290,000
90,000
1855,
471
281,000 | 1,434
550,000
200,000*
The South Lode is at the junction of the trap with a
bed of conglomerate, which crosses the Minnesota tract
a short distance south of their main vein. They there-
fore opened it in 1852, by driving a cross cut from their
adit level. Large masses of copper were found by the
* During this year the stock was increased to 20,000 shares, par
value, $1,000,000.
250 MINES OF COPPER.
side of the conglomerate, whereupon a shaft was sunk
in this neighborhood. The lode was found to be, in
some places, five feet wide, and filled for a distance of
40 feet with a mass of copper almost continuous. Upon
drifts the lode is very rich, carrying masses of copper
interspersed with a good deal of silver.
The Rockland Mining Company is at work on lands
which originally belonged to the Minnesota Company.
It was formed in September 1853, with a capital stock
of $500,000 in 20,000 shares, the terms of agreement
with the Minnesota Company being, that the land should
be put in at $100,000. It was, in fact, a dividend on
Minnesota stock.
The tract belonging to the new company adjoins the
Minnesota lands, and appears to carry across its entire
breadth (some three thousand feet) a continuation of the
veins just described. Some old openings were found,
and explorations in these were so promising that the
work was begun at that point. An adit was opened on
the north side of the bluff. At a distance of 390 feet
from the opening, it cut the north vein at the depth of
170 feet, and 230 feet further it lays open the main
and the south lodes at about the same depth. At the
date of the last printed report,* four shafts had been
opened and sunk to a depth varying from 80 to 130
feet in depth, and a fifth had been commenced. Three
levels had been opened, one 72 feet from the surface,
the adit level on the vein, and one 10 fathoms below it.
Besides this a cross cut had been driven from the adit,
which reached the Minnesota South Lode, at the distance
* May 1st, 1856.
MINES OF COPPEK. 251
of 275 feet from Rockland vein. Upon this drifts were
made east and west, stripping the vein from the conglome-
rate which forms the foot wall. This vein is about two
feet thick, and is said to be good "stamping lode."
Barrel-work of from 10 to 20 pounds has been taken
from it. At a distance of 100 feet south of the Rock-
land vein, this same cross-cut opened a large flat vein,
from which pieces weighing from 50 to 100 pounds were
taken. At shaft No. 4, a mass of copper, weighing
30 tons, and bearing unmistakable marks of the tools
of the ancient miners, was found ; from the adit level also,
many masses have been taken, some of which weighed
15 tons.
This is considered one of the most promising mines
on the lakes. The product of the first years operations
was 23 tons, that of the second 137 tons of 70 per cent.
The National Mining Company in 1852, opened a
vein lying between the conglomerate and trap, in the
same range with, but at some distance from the Minnesota
property. Ancient mine- work was discovered here, con-
sisting of a shaft sunk to the depth of about 50 feet,
timbered and scaffolded. A nearly continous sheet of
copper extended down its side. Work was prosecuted
vigorously during the following winter, and the next
year 35,808 pounds of masses, and 46,046 of barrel- work,
averaging 72 per cent, of pure copper, were shipped.
In January, 1854, 206 fathoms had been stoped, and
2,307 fathoms were ready for that operation. The vein
is remarkable for lying between two dissimilar forma-
tions, and for containing scarcely any veinstone, being
almost one solid sheet of copper for a considerable dis-
tance from the point at which it was first opened.
252 MINES OF COPPER.
The Norwich Mining Company has a regular vein of
quartz, containing radiated epidote, native copper and
red oxyd. The workings are extensive and the vein
rich.
There are many other mines in this region besides
those which we have noticed ; hut those we have named
furnish the most instructive lessons upon the nature of
veins and the prospects of mining in this vicinity. We
have been somewhat full in regard to the particulars of
these workings, but we do not feel that we have been
unnecessarily prolix, as the Lake Superior region is so
very important, the mines more extensively and scienti-
fically worked than any of the same metal in our coun-
try, and much misunderstanding prevails concerning
them.
Of the PORTAGE LAKE mining district we have little
to say. The mines are not fully developed ; there are
few, if any, regular veins, the metal being found dis-
seminated through beds which run with the formation,
and differ but little from the other trappean beds with
which they are associated. They are more regular in
their course, and more uniform in their contents, than
similar deposits on the Ontonagon River. Ancient ex-
cavations have also been found extending over a great
length of vein.
The great value of the Lake Superior district, as a
mining region, may be gathered from Mr. Whitney's
table of the yield of the more important mines. From
this it appears that from 1845, when the first casual ex-
cavations were made, up to the close of 1853, 4,824
tons of pure copper had been taken from these mines,
and considerably more than one-fourth of this total had
MINES OF COPPER. 253
been sent off in 1853. At the date of publication of
his book on the Metallic Wealth of the United States,
there were 75 mines at work, employing 2,800 men.
The entire amount expended upon the whole region, up
to December 31st, 1853, he estimates at $4,800,000 ;
and the value of copper produced, at an average price
of 25 cents a pound, was $2,700,000. Of this, $504,000
had been paid out in dividends, and the rest applied to
the further development of the mines. Of the capital,
a considerable portion was invested in mines which pro-
mise remarkably well, but which had just been opened
at the time the above estimate was made ; a great deal
of it, however, was thrown away during the wild excite-
ment which characterized the first reckless speculations
in this district. The mines are permanent, and what-
ever may be the fluctuation in the market prices of the
stock of individual companies, there can be no doubt of
the great value of the veins of the region. The yield
for 1854 was estimated by Mr. Whitney at 2,000 tons
of pure copper.
The trap range extends into Wisconsin, but no valu-
able veins of copper have yet been discovered beyond
the borders of the State of Michigan.
On the northern shore of the lake, in Canada, numer-
ous companies have been formed and have attempted
mining in the trappean rocks, as well as in those of the
azoic period. The trap appears to correspond with that
of the south range on Keweenaw Point. No workings
are now going on here, but from 1846 to 1849, a power-
ful vein was wrought on Spar Island and the main land
opposite. The copper occurs in the form of pyrites and
22
254 MINES OF COPPER.
variegated sulphuret, but the ore is too small in quantity
to be worked. Native silver and sulphuret of zinc have
been found in the vein on the mainland.
On Michipicoten Island, in 1846, operations were
commenced by the Quebec and Lake Superior Mining
Association. Formidable preparations were made. An
adit was driven 200 feet, three shafts sunk, a level com-
menced, and smelting furnaces erected. At last, after
expending $150,000, they discovered that there was no
ore to smelt.
On the north shore of Lake Huron, veins are found in
a white sandstone or quartz rock, containing sulphurets,
chiefly pyrites. The Bruce Mine is situated about fifty
miles south of Saut Ste. Marie, and has been success-
fully worked. During the first year an open cut, 126
feet long and 5 deep, was made, from which 240 tons of
ore were taken. After this shafts were sunk, smelting
works erected, and a great deal of money wasted on un-
profitable improvements. In spite of this bad manage-
ment, however, the mine pays a good dividend, and is
likely to do still better.
ORES OF THE MISSISSIPPI VALLEY.
In the Mississippi Valley, numerous cupriferous depo-
sits occur at the junction of the lower Silurian limestone
with the azoic rocks. They are often found in connec-
tion with the lead ores of the west, which they resem-
ble in their mode of occurrence.
In Wisconsin, these ores lie far to the south of the
trappean rocks. They occur chiefly in the neighbor-
hood of Mineral Point, in what is called the Ansley
MINES OF COPPER. 255
Tract. At that place the ore occupies a fissure in the
limestone 14 feet wide at the surface, and traced for a
quarter of a mile. For a depth of 15 feet, the fissure
is filled with weathered rock or gossan, as it is common-
ly called, together with lumps of sulphuret and carbon-
ate of copper. Below that depth is clay with a little
ore scattered through it. About a million and a half
pounds were taken from this fissure, fifty thousand of
which were sent to England with the effect of bringing
the shippers in debt. As the underlying sandstone is
only 100 feet from the surface, and as it is probable that
the ore will fail there, the deposit cannot be regarded as
valuable.
In Missouri, the copper ores also lie in Silurian rocks,
resting in basins of the older rocks, the principal of
which are granite and porphyry. The Mine La Motte
has a celebrity, according to Mr. Whitney, far beyond
its actual value. The property includes 24,000 acres,
and contains numerous so-called mines. The most stea-
dily wrought of these is the Philadelphia mine. Here
the sandstone and limestone rest on the granite. The
metalliferous deposit is a bed lying between a stratum of
sandstone and another of hard crystalline limestone.
It is a slaty mass, from 12 to 18 inches wide, contain-
ing galena in flat sheets, and pulverulent ores of cobalt
and nickel. The copper pyrites occurs in fissures in the
limestone, disseminated through a thickness of six or
eight feet. This metalliferous stratum forms a lenticu-
lar mass, dipping at small angles in every direction from
the centre, and appearing to be several hundred feet in
diameter. Mr. Whitney thought the mine worthless.
256 MINES OF COPPEK.
He does not appear to have formed a more favorable
opinion of the other mines in the same State, which re-
semble somewhat the Mine La Motte.
ORES OP THE ATLANTIC STATES.
Ores of copper occur abundantly in the metamorphic
rocks, or crystalline schists and associated igneous masses
which extend along the eastern slope of the Appalachian
chain, from Vermont to Georgia. Mr. Whitney says in
reference to them :
" These deposits, wherever examined, are found to
bear a striking similarity to each other ; they are never
found occurring in well-developed transverse or fissure-
veins ; or at least, such has never come under my obser-
vation. They all form masses parallel with the forma-
tion and possessing all the characteristics of segregated
veins ; or if, as is occasionally the case, apparently cross-
ing the strata at an angle, such branches will be found
subordinate to segregated masses, and not exhibiting, in
an unmistakable manner, the phenomena of fissure-veins.
The ores thus occurring are almost always pyritous,
with, occasionally, a small portion of the variegated ;
and they do not usually appear to be oxydized to any
considerable depth from the surface. Sometimes specu-
lar and magnetic oxyds of iron form the outcrop of the
vein, and are replaced to a greater or less extent be-
neath by ores of copper. On the southwestern side of
the Appalachian chain, in Tennessee, this decomposition
and the formation of gossan has, however, taken place
on a large scale ; in other respects the deposits of the
MINES OF COPPER. 257
ores are similar to those of the eastern slope, except that
they are on a scale of greater magnitude."
MAINE. There are a few quartz veins, carrying cop-
per pyrites, in this State, but nothing worthy of atten-
tion.
NEW HAMPSHIRE. There are numerous localities of
copper pyrites in this State, hut none of them have, as
yet, been worked to any extent.
Dr. Jackson, in his Report on the Geology of New
Hampshire, mentions several towns as containing ores of
copper, but condemns the majority of them as being in
too small quantity for profitable working. Of two, he
speaks favorably one in the town of Bath, the other in
Warren.
At "Warren, there is a remarkable bed of tremolite,
forty-eight feet wide, between walls of mica slate, which
is impregnated with copper pyrites. It is also mixed
with blende, galena, iron pyrites, and a little rutile.
There are also several quartz veins on the property,
one of which carries lead, copper, and zinc, the predom-
inant ore being argentiferous galena. At the time of
my visit, late in 1856, there were two shafts one in
the tremolite bed, the other in the quartz vein. A few
tons of ore had been taken out, chiefly from the upper
shaft, or that sunk in the quartz. The tremolite is
soft and easily crushed, and though it is not a regular
vein, yet its great extent may enable it to be profitably
worked. It is also quite possible that, on further ex-
ploration, veins may be found cutting it, in which case
it might be expected that they would be enriched as they
traversed it. There are, in this neighborhood, small
22*
258 MINES OF COPPER.
veins which cross the direction of the strata. The
whole region would justify a more extensive exploration.
Preparations are now being made to work the mine for
both lead and copper.
At Unity, on the farm of James Neal, is a vein of
iron and copper pyrites, one to three feet wide, running
with the stratification, which has been traced for two
thousand feet. Whitney reports the ore as yielding 12
per cent., and speaks encouragingly of the locality.
VERMONT. Several localities of copper pyrites exist
in this State. At one of them, in Corinth, some open-
ings have been made, from which ore has been sent to
the Revere Copper Works, at Boston. At Strafford,
in 1829, a furnace was built for the purpose of smelt-
ing the copper pyrites which occur there, mixed with
iron, but the attempt did not succeed.
MASSACHUSETTS. A little pyrites and erubescite has
been found in this State, in veins which have been
worked for lead in Northampton and Southampton
but not in sufficient quantity for mining.
CONNECTICUT. There is quite an extensive copper
mine at Bristol, which was first worked in 1836. It
is a contact deposit, at the junction of the sandstone of
the Connecticut River Valley with the older metamor-
phic rocks. The linear extent of metalliferous ground
is eleven hundred feet. The mine is opened, to the
depth of forty fathoms, by an engine shaft, which, at
the date of the Report of Professors Silliman and
Whitney, (August, 1855,) was the only working shaft.
The width of the ore ground, from east to west, (the depo-
sit running N. E. and S. W.) is one hundred and twenty
MINES OF COPPER. 259
feet, a width which is maintained on descending. Till
recently, the workings were confined to micaceous and
hornblende slates, sometimes passing into gneiss, and
including large irregular "horses" of granite, which
rock appears to have formed segregated masses, lying
rudely parallel with the bedding of the schistose rocks.
The strike and dip of these, however, is found through-
out the mine to be very irregular, and there is evidence
in the confused character of the ground, as well as in
the slip joints and polished surfaces of the rocks, that
motion of the various beds upon one another has taken
place along lines of limited extent and varying direc-
tion. The distribution of the ores in the metalliferous
ground now under consideration, is found to be as
irregular as is the structure of the ground itself.
They consist principally of the vitreous, with some
variegated ore, and a comparatively small amount of
copper pyrites. In general, these ores are found occur-
ring in bunches and strings, which, though preserving,
usually, an approximate parallelism to the line of con-
tact of the formations, cannot be traced continuously
for any considerable distance. Hence the irregularity
of the workings, especially in the upper levels, which
have been extended in upon various bunches of ore,
or in search of others supposed to exist in certain direc-
tions, without any particular system or previously con-
certed plan. This has been the greatest drawback on
the prosperity of the mine, since the ore ground was
too wide to be all taken down by the miners, and the
distribution of the bunches of ore in it was too irregu-
lar to admit of their being found without occasional
260 MINES OF COPPER.
expensive excavations in dead ground. In general,
throughout the mine, a tendency to a concentration
of ore around the masses of granite may be remarked,
and the latter are not unfrequently well filled with
strings and bunches of ore, especially near their exterior.
"The limits of the ore ground, to the west, or in the
direction of the older rocks, the sandstone being to the
east of the contact line, have never been well ascer-
tained, and must be somewhat irregular, as would be
expected from the nature of the deposit." One of the
levels -going north from the twenty fathom cross cut,
has been driven along a regular wall, dipping easterly
at an angle of 62, found also in the thirty fathom
level, but traceable in neither, more than one or two
hundred feet. Within this ore ground, the average dis-
tribution of copper is very uniform. Between the sand-
stone and this metalliferous belt, lies a soft talco-micace-
ous slate, with bands and nodules of harder rock, called
the "great fluckan." It is twenty-seven feet wide in
the twenty fathom level, but gradually increases as it
descends, till at fifty fathoms deep it has attained a width
of fifty feet. The authors of the report do not expect
that it will continue to widen indefinitely, but regard it
as a lenticular mass, which will narrow again. It con-
tains vitreous ore disseminated through it in small par-
ticles, and occasionally concentrated into strings and bun-
ches of considerable size. It has so far yielded, on stam-
ping arid washing, over three per cent, of ore, containing
thirty per cent, of copper. It is so soft as not to require
blasting, and when exposed to air and moisture, disinte-
grates to a fine clay. Besides these deposits, a seam of
MINES OF COPPER. 261
ore has been cut in the sandstone, not far from the
flucan.
The mine was opened in 1836, and though frequently
changing owners in the following years, produced ores
which were chiefly sent to England. It was not till
1847, that it was worked to any considerable extent.
Since then, over 1800 tons of ore have been taken out
and sent to mai'ket. It is a favourite ore with smelters,
not only on account of its composition but of the admi-
rably uniform manner in which it is dressed. The yield
varies with the character of the ore. I have made nu-
merous analyses of samples of cargoes and have found
none of lower yield than 18 per cent, of copper, while
some gave over 50 per cent.
Copper has been found associated with the lead at the
different localities of that metal in this State, but as yet
in no important quantity.
NEW YORK. There are plenty of mineralogical cop-
per localities in this State, but none sufficiently impor-
tant to justify mining operations for that metal alone.
At the Ulster Lead Mine, copper pyrites has been found
in sufficient quantity to render it worthy of attention
and separation from the lead.
PENNSYLVANIA. The principal mines in this State are
in the new red sandstone and will consequently be no-
ticed under that head. Those in the older rocks have
so far not been profitable. The Gap Mine, in Lancas-
ter county, is the oldest of these. It was first opened
in 1732, and afterwards taken up by another company
which made large expenditures, but it has never paid.*
* Recently it has been worked for nickel, and copper ore of about
10 per cent, has been obtained as a secondary product.
262 MINES OF COPPER.
Near Pottstown, at the St. Peter's mine, a shaft has
been sunk cutting a vein of calcareous spar, containing
blende and copper pyrites.
MARYLAND. A number of mines have been opened in
this State and a few are still in operation. In Frede-
rick county, near Liberty, work was carried on for some
time, but finally abandoned. Attention was then turned
to the New London mine, in which a shaft was sunk and
levels driven by Isaac Tyson, Jr., who worked it for a
while and then gave it up.
Dolly Hide Mine, in the same neighborhood, held out
for a time stronger hopes of success. It was worked
in a broad band of crystalline limestone, which, in some
places, is 100 feet thick, containing numerous parallel
layers of ore, mixed with quartzose matter, colored
brown by iron, manganese and copper. It also contains
a "black dirt" which is a product of decomposition,
having variable quantities of black oxide of manganese,
mixed with copper and iron. The copper ore when not
decomposed is chiefly erubescite, mixed with pyrites, the
latter usually scattered in minute specks through the for-
mer. Some masses of malachite, chiefly botryoidal, of
considerable size, have been taken from this mine.
Work was carried on irregularly, at intervals, up to
1846, when it was leased to Isaac Tyson, Jr., who car-
ried it on for several years. Finally a stock company
was formed, with a capital of $600,000. They worked
it but a short time before they abandoned it. The de-
posits, though extensive, are too uncertain and irregular
to justify large outlay and they cannot be worked with-
out it. There is no likelihood at present that work
there will be resumed.
MINES OF COPPER. 263
The yield of the mine from 1842 up to May 1843 is
stated, in the published reports, to have been 191,933
pounds of ore averaging 22 13-32 per cent, and 127 tons
of "black dirt" averaging lOf per cent, of copper.
In the neighborhood of Sykesville, there is another
metalliferous belt, occurring among talcose, chloride and
hornblende slates, the veins being parallel with the for-
mation. Of these, the most important is the Springfield
mine.
Springfield Mine. This mine was originally opened
by the Messrs. Tyson for iron, and afterwards worked
for copper. It is about a mile from the Sykesville sta-
tion of the Baltimore and Ohio Railroad and 32 miles
from the city of Baltimore. It lies among slates which
are micaceous, talcose or chloritic; the talcose slate
closely resembling that of the gold regions of Virginia
and North Carolina. Gold has been found in small
quantity in the iron ores of the neighborhood. The
vein is parallel with the stratification of the slates and
dips with them, its general direction being about north
30 east; south 30 west, and the dip nearly vertical.
On the surface there is a very powerful outcrop of a
quartz rock impregnated with specular and magnetic
oxides of iron in small granules. The same rock makes
its appearance at the shallow openings along the line of
vein, wherever the surface soil has been penetrated. A
little deeper, the oxides of iron become sufficiently concen-
trated to justify working, and accordingly the upper levels
have been stripped for the use of the neighboring Elba
furnace. Still lower are found carbonates and silicates
of copper, which are soon replaced by copper pyrites.
264 MINES OF COPPER.
The vein has been opened by an engine shaft, which
at the depth of 66 feet, is cut by an adit level, 500 feet
long, provided with a tram road for the removal of ore.
At the time of my visit, in February, 1857, four levels
had been driven and some stoping done. The vein thus
exposed, has distinct walls and selvages. In the forty-
five fathom level, there is a "horse" and a "slide" de-
scending at an angle of 45 degrees. In the neighbor-
hood of these, there are concentrations of yellow ore
about four feet in thickness. A new shaft, inclined at
the angle of the slide has been made, and it serves the
double purpose of opening the mine more thoroughly,
at the same time that it ventilates it.
This mine is steadily increasing in productiveness and
the ores enriching as they descend. During the year
ending April 1st, 1857, 300 tons valued at $17,896.92
were mined and sent to market. The report to the
stockholders bearing that date, estimates the present
capabilities of the mine at 50 tons a month, and ex-
presses the belief that in the following October, it will
reach 125 tons a month, owing to the greater amount
of ground which will be opened, and especially to the
sinking of a new shaft upon a vein of erubescite recent-
ly leased. The ore of the old vein is yellow pyrites
mixed with magnetic and specular iron. The last lot
sent to the Baltimore market (December 1857,) contained
16.03 per cent, of pure copper. Some nickel and co-
balt are found in this mine.
The company is chartered in Maryland ; the number
of shares being 100,000, at a par value of $5 per share.
Mineral Hill Mine is six miles northeast of Sykes-
MINES OF COPPER. 265
ville. There are four veins, parallel with each other,
running north 15 east, in a talcose and chloritic slate.
One of them appears to be a fahlband of slate, impreg-
nated with copper pyrites and small bunches of cobalt
ore. The three others carry, at their outcrops, magne-
tic and specular iron with traces of gold; and, as / in
Springfield, these gradually give place to copper pyrites
and erubescite in the deeper workings.
There are three shafts, from which some ore has been
taken.
Patapsco Mines. This is owned by a Philadelphia
company. It was originally worked in a heavy bed of
soft iron ore, containing very handsome specimens of
fibrous malachite and some copper pyrites. In the
deeper workings more copper pyrites was found, which
was gradually substituted by cobalt. The mine proved
unprofitable.
Bare Hill Mine. The mine is about seven miles from
the city of Baltimore. Although irregularly worked, a
good deal of ore has been taken from it. These ores
are pyritous, interspersed with chromic, magnetic and
specular iron. The mine has been idle for several
years, on account of law-suits respecting its title.
VIRGINIA. In many parts of this State' copper is
found; often native in sheets lining the joints of the
epidotic trap rocks of the Blue Ridge and in threads
penetrating them ; and sometimes in the form of copper
pyrites, erubescite, red oxide of copper, &c.
Manassas Crap Mine. At Manassas Gap, in Fau-
quier county, there are some remarkable deposits of cop-
per. They consist chiefly of the oxides of that metal
28
266 MINES OF COPPER.
embedded in igneous rocks, though there are also veins
of pyrites on the land. There are two groups of veins
imbedded in slates which have a nearly vertical dip.
The first group is composed of pyrites veins, parallel
with each other and with the formation ; the other con-
sists of veins containing oxide and native copper and
running in different directions. One has a course of
north 30 east, parallel with the strike of the slates ;
the other runs north 70 east. This cross vein had, at
the time of my first visit, been cut in a shallow trench,
dignified by the name of a trial shaft. In that, it appeared
to be from 10 to 12 feet thick, and to dip at an angle of
about 62. At the time of my second visit, work had
been commenced. An adit had been cut in the side of
the hill, towards the veins, with the intention of reach-
ing them at a point where they were supposed to inter-
sect. In this adit another vein had been cut. A shaft
had also been sunk away from the vein and a gallery
driven through dead rock in the hope of reaching the
vein again. These openings were expensive and unpro-
fitable. The vein would have been proved in a more
economical way by sinking an inclined shaft upon it,
and then, if found to continue as it had begun, more
extensive openings might have been made.
The mine has, I believe, been abandoned. Nothing
could have been better, however, than the surface ore.
I analyzed several samples of it, and think fifty per cent,
to be a moderate computation for the average yield.
The vein-rock itself contained over two per cent, of
copper.
In Nelson County on the Blue Ridge, not far from
MINES OF COPPER. 267
Rock Fish Gap, there is a powerful quartz lode contain-
ing copper pyrites. It has never been worked to my
knowledge.
In Albemarle, at the Faber lead mine, copper pyrites
also occurs, together with galena, and blende or sulphu-
ret of zinc.
The principal copper region of the State is in the
south-western part, in the counties of Carroll, Floyd
and Grayson. Here the slates of the Blue Ridge ap-
proach the limestones of the Alleghanies, and the two
ranges of mountains become blended with one another,
the general trend of both being north-east and south-
west. The district is on the south-western slope of the
Blue Ridge, about twenty-five miles from a railroad. The
geological structure of the country consists of slates,
chiefly micaceous and talcose, with some conglomerates,
underlaid, according to Dr. Dickerson's report, " with a
fine-grained, compact hornblende and felspar, analogous
to green stone." Among these shales lies a broad metal-
liferous belt, continuous, it is believed, with the great
cupriferous deposits at Ducktown, Tennessee, traceable
by an outcrop of gossan for three hundred and sixty
miles. Within this belt are found several distinct beds
of ore, the outcrops of which are known by the name
of "leads." Dr. Dickerson names five of these, the
Early, Dalton, Dickerson, Toncray and Native leads,
and says that he has heard of others, but did not see
them. These belts of ore follow, to some extent, the
direction of the bluffs upon which they occur. " Seams
of white quartz, interlaid with chloride greenstone,
forming small feeders, often occur, and invariably carry"
268 MINES OF COPPER.
copper ore. At such points, the direction of the lead
is N. 45 E. The width of these leads varies from 114
to 32 feet. Immediately under the gossan, a much
decomposed smut ore occurs in a greatly altered rock,
so soft that it can be removed by the pick alone. It is
a mixture of red oxide with sulphuret of copper, and
with oxide and sulphuret of iron. Below this, lies an
iron pyrites intimately mixed with quartz, which is known
here as arsenical iron, though there does not appear to
be any arsenic in it. From the description in Dr. Dick-
erson's report, it would seem that these cupriferous
deposits are in the form of lenticular masses, the result
of decomposition of the underlying mass. He informs
us that the body of ore is thicker in the valley, and that
where the copper ore lies high, the dip of the so-called
arsenical iron is but slight, whereas when it is deeper,
the dip is steeper. The depth of this underlying
mundic is not known, as jt has not been penetrated
deeper than four feet. The workings for the examina-
tion of these copper deposits have been chiefly horizon-
tal galleries, driven in from the sides of the hills along
the course of the lead, and cross cuttings made at
various elevations in the east flank of the mountains.
There are numerous workings along the lines of these
leads, but it is not easy to get information concerning
them. The oldest of these is the Cranberry Mine.
" The property contains one hundred acres, and extends
half a mile on the lead. Two shafts had been sunk on
the south end of the lead, below the summit of the
bluffs, which proved the lode upwards of 600 feet.
From the side of the hill a horizontal gallery was driven,
MINES OF COPPER. 269
on a course of 45 E. of N., and extended upwards of
400 feet, giving an average width of seventeen feet of
copper ore. The south wall is well defined, being composed
of a talco-micaceous slate, containing now and then small
patches of garnets of beautiful form and color. Nume-
rous small vugs occur in this gallery, many of which
are filled with the finest crystalline forms of ore." The
ore is taken out of variable richness. Dr. Dickerson
speaks of having seen masses of oxide weighing more
than a ton, and containing sixty per cent, of metallic
copper.
There are twelve or fourteen openings in this great
metalliferous belt, worked mostly by companies organized
on the copartnership system.
The Cranberry Mine is one of the oldest of these
openings. Its property contains a hundred acres, and
extends half a mile upon the lead. At the date of Dr.
Dickerson's report, two shafts had been sunk below the
summit of the bluffs. From the side of the hill a hori-
zontal gallery had been driven for over 400 feet,
cutting copper ore of an average width of seventeen
feet. A hundred feet from the opening, streaks of
flucan were discovered, and near them a large deposit of
red oxide of copper. The south wall is well defined,
consisting of talco-micaceous slate containing fine gar-
nets. In this gallery are numerous vugs, many of
which are filled with fine crystals. The ore bed is com-
posed of two distinct layers, the upper containing the
best ore. The average percentage of the ores taken
from this mine is set down at 26'43.
The Wild Cat Mine adjoins the Cranberry on the
.23*
270 MINES OF COPPER.
West, its openings being made upon both the Early and
the Dalton leads. The property contains three hundred
and fifty acres, and is seventeen miles from Mack's
Meadows, a station on the Virginia and Tennessee rail-
road, with which it is connected by a good turnpike
road. It extends half a mile on either lead. Mining
was commenced here in February 1855, by an open
cut, from which a gallery was driven into the hill. The
geological features of this mine are the same as those of
the last described. The veins in the valley dip more
perpendicularly, and are considered richer. The north
wall is well defined, and filled with small garnets.
The Ann Phipps Mine is next to the West, owning
a property of a hundred and forty miles, extending a
mile upon the Early lead. Work was commenced late
in March, 1855. According to Mr. Richardson's letter
in the London Mining Journal, the channel of mine-
ralized ground on this estate is one hundred feet thick,
containing a champion lode eight feet thick, on a foot
wall of mica slate, having an underlie of 55 S. E.,
and a range, as traced by out-croppings, of 50 N. of
E., which will probably change to 35 in the deep work-
ings. The country and hanging wall are composed of
mica and clay slate with garnets. The matrix is quartz
and iron pyrites. In the higher levels, there is much
gossan and decomposed slate. There is also a strong
flucan on the foot wall. On the surface there is much
bright gossan, impregnated with grey and black ore,
the branches of the lode. At thirty-five feet below,
these concentrate, and a solid mundick is reached, filled
with yellow and grey ore. Of the yield of this mine, I
have no statistics.
MINES OF COPPER. 271
The Dalton Mine is three-fourths of a mile south-east
of the Ann Phipps. The shaft, according to Mr.
Richardson, is sunk in a ravine, penetrating twenty feet
into the lode, and twelve into solid mundick. As usual,
upon the surface, there is gossan. The quartz vein,
twelve feet thick, contains eight per cent, of yellow
copper.
Of the other mines in this region, I have no reliable
information.
NORTH CAROLINA. There are a number of copper
mines in this State, none of which have, as yet, pro-
duced a great deal of ore, though many of them look
very promising. Copper is certainly very widely dis-
tributed through the state. In the north-western
corner, at Ore Knob, in Ashe County, a mine has been
worked for several years, and has produced some excellent
yellow ore. This appears to be in the same range with
the mines in south-western Virginia. Following the
same line down along the Eastern slope of the Unaka,
Smoky, and other mountains dividing Tennessee from
North Carolina, there are numerous deposits of copper.
On my visit to that region, in December, 1855, there
was much excitement in regard to ores of this metal,
and numerous openings had been made, but too imper-
fect to enable any one to arrive at any definite conclu-
sions in reference to the matter. In the south-western
part of the State, on both sides of the Blue Ridge,
among the micaceous and talcose slates, there were evi-
dences of the presence of copper, and at numerous
points upon the creeks in Macon and Jackson counties,
yellow and grey ore of fine quality had been taken out
272 MINES OF COPPER.
in small quantities. It is my impression that this region
will, on proper exploration, be found to contain not a
little metallic wealth.
An important region for gold, silver, copper and lead,
exists in the centre of the State, occupying the counties
of Gruilford, Cabarras, Mecklenburgh and Davidson.
North Carolina Copper Company. The mine worked
by this company is about nine miles from Greensboro' in
Guilford County. It was formerly worked for gold, and
known as the Fentress or Stith's Mine. In 1852, it
was purchased by a New York Company, and by them
it has been worked for copper only. The cupriferous
deposit has a direction parallel with that of the slates
in which it is enclosed, about N. 30 E. ; its dip, which,
at the surface, is only 15, gradually increases ; and is,
at seventy feet in perpendicular depth, about 45. The
ore is almost solely pyritous copper, associated with
some sulphuret of iron. It is said, on good authority,
that there is a large quantity of ore exposed, but the
work has thus far been conducted with an entire want of
judgment, the only aim seeming to be to raise as much ore
immediately, without regard to the future of the mine.
At the time of the publication of Whitney's metallic
wealth of the United States, to which I am indebted for
the above information, it was reported by the parties in-
terested, that they were raising one hundred tons of
twenty-five per cent, ore monthly. I have been able to
get no further information, except that the company in-
tend erecting smelting furnaces for separating the me-
tallic from the earthy parts of the ore.
In most of the old gold mines, copper pyrites is found,
MINES OF COPPER. 273
and much of this ore has accumulated from the gold
workings. Some of them are now worked conjointly
for both metals, and the opinion of those who have had
opportunities of judging, is, that they will prove valu-
able for copper.* At the McCullock Mine, in Guilford
County, the copper ore is found in a layer of quartz,
overlying iron pyrites, the gold being underneath both.
TENNESSEE. Following the range of mountains be-
tween this State and North Carolina, from the Virginia
frontier, the explorer finds copper in different localities.
Imperfect explorations have been made at various points
on this range, without any satisfactory result, so far as
I have been able to learn, except in the extreme south-
eastern portion of the State. There, in Polk County,
on the Ocoee River, is a very remarkable deposit of
copper, which has attracted no little attention, and sent
a good quantity of ore to market.
The region in which these ores occur is an old Indian
province, known by the name of Ducktown. It is an
elevated basin or trough, lying between the Unaka and
the Blue Ridge, about a thousand feet above the level of
the valley of East Tennessee. The country is cut up into
knolls and ridges of tolerably uniform height, and the dis-
trict is traversed by the Ocoee River, a tributary of the
* In a private letter to the author, Dr. F. A. Genth says of the
mines of this region : " As a general thing, all true veins, '. e., such as
intersect the strata, and are not merely metalliferous strata of the
formation, apparently will turn to copper veins at a greater depth.
They contain generally less gold near the surface, rarely averaging
more than fifty per cent, per bushel, but at and below the water level,
the indications of copper appear, and become stronger with every foot
sinking.
274 MINES OF COPPER.
Tennessee. The geological formation is made up of mica-
ceous and talcose slates, with some hornblende, dipping
at a high angle towards the south-east, and running N.
20 E. These are crossed by quartz veins, but the
great metalliferous beds are parallel with one another
and the strike of the strata. At the time of Whitney's
visit, there were but two of these known, and upon only
one of them had any important openings been made,
but Prof. Safford, the Geologist of the State, writing in
1856, speaks of seven or eight distinct veins, the course
of six of which, he figures on his map.
The appearance of these veins is remarkably uniform.
The surface is marked by a heavy outcrop of gossan,
which is particularly conspicuous on the knolls and
ridges, where it is often found in great blocks scattered
over a width of fifty or a hundred feet.* Beneath this
gossan is found a mass of black cupriferous ore, which,
like the gossan, has resulted from a decomposition of a
mixture of the sulphurets of copper and iron. The
depth at which this smut ore occurs varies, being greater
on the hills than in the valleys. In the former locality,
it is found 80 or 90 feet below the surface, in the latter
it is reached at 25 or 30. It corresponds very closely
as might be expected, with the water level. It is a mix-
ture of the red oxide of copper with the sulphuret and
some silicious matter, varying in its yield of pure copper
* J. P. Lesley, in his report on the Hiwassee mine, suggests that
these veins may have been originally deposited as sedimentary rocks
and subsequently altered by heat. Their parallelism is accounted for
by the folded condition of the stratification, the upper curves having
been removed by denudation.
MINES OF COPPER. 275
from 15 to 60 per cent., 20 per cent, being about the
average. Below this is found the unaltered mineral of
the vein, a very hard rock consisting of a pinkish iron
pyrites mixed with quartz and containing some yellow
copper ore.
The thickness of the veins containing these deposits is
often enormous. At the Hiwassee mine, the body of
black ore was said to be 45 feet wide, and at the Eure-
ka, Mr. Staunton, the secretary, informs me there is
a mass of solid ore 52 feet in width. At other points it
thins out, and finally disappears. The thickness is
equally variable. At some places it is accumulated in
conical masses to the amount of several hundred tons.
Whitney estimated the average width of the deposits at
10 feet and the thickness at 2.
One of the most remarkable features about these mines
is the great economy with which they may be worked.
Shafts can be sunk through the gossan without being
timbered, and the ore can be taken out with picks and
shovels, while the veins are so wide that several men
can work abreast in the levels. The ridges too are so
posited, as to afford great facilities for driving levels
across the veins.
The permanent value of these mines will of course
depend upon the character of the veins below the oxide,
for, however rich and abundant that may be, it is evi-
dent that it must soon be worked out. The average of
the rock is altogether too poor to admit of its being pro-
fitably worked, and unless the copper pyrites should be
found to concentrate in rich bunches, these mines must
be abandoned as soon as all the black ore is removed.
276 MINES OF COPPER.
Impressed with this truth, the miners have prosecuted
certain openings with a view of determining this point.
The Hiwassee mine, which has nearly if not quite ex-
hausted its black ore, has cut several bunches of yellow
ore in its lower levels, which have excited the hopes of
its owners. According to the best information I have
been able to obtain, however, I cannot regard this ques-
tion as decisively settled.
The history of mining enterprise in this region, as
given by Professor Saiford, in his report to the Legisla-
ture, is briefly as follows. The first discovery of copper
was made by a Mr. Lemmons, in 1843. He was
washing for gold at the present site of the Hiwassee
mine, and found red oxide of copper. Shortly after
this, a company discovered the black oxide, but consid-
ering it worthless, they did not include it in a package
of the minerals and rocks of the vicinity which they sent
to New York for analysis. Receiving necessarily an
unfavorable report, they suspended operations for the
time being. In 1847, being informed by a German of
the value of the black oxyd, they made a shipment of
about- 14 tons, averaging 25.3 per cent. About the
same time a furnace was erected to make iron out of the
gossan, but the metal produced was red short and the
enterprise was abandoned. Still, certain facts were ascer-
tained, such as the green flame of the furnace, and the
cupreous hue of the iron after it had been heated and
plunged into water. In 1849, Mr. John Caldwell came
into the neighborhood, and mainly through his indefati-
gable energy, public attention was attracted to this
region. In 1850, the Hiwassee and Cocheco companies
MINES OF COPPER. 277
were incorporated. The following year, the Tennessee
Mining Company broke ground, and after that the tract
was gradually taken up by the fourteen companies who
now occupy it.
The Hiwassee Mine commenced regular operations
in May, 1852, on a vein 45 feet wide, included in walls
of mica slate. Other veins are spoken of as parallel.
The main lode corresponds in strike and dip with the
strata, having a direction of north 20 east and a dip of
80 to the southeast. The average depth of the black
ore was estimated by Lesley at five feet, and its width
at 30, the whole amount being calculated at 7200 tons.
The mine has sent to market about 6000 tons and has ex-
hausted its smut ore. Efforts are now making to strike
the yellow sulphuret and the prospects are encouraging,
several deposits of greater or less magnitude having
been reported. As in all other mines, the gangue be-
low the point of decomposition is a hard quartzose rock
containing much iron pyrites and some yellow copper.
The adit of this mine is 920 feet long, and serves as a
draining gallery for the mine. The entire length of the
shafts in September, 1856, is stated by Professor Safford
at 641 feet, and the extent of the galleries at 2784 feet.
The capital stock is $240,000, divided into 60,000
shares.
The Eureka Mine is worked in a metalliferous belt
300 feet wide. This has been traced by an outcrop of
gossan for 2250 feet, in the direction of the strike of
the strata. The mine has been opened by a main shaft
105 feet deep, from which galleries have been driven
across the belt. Several beds of ore have been cut, and
24
278 MINES OF COPPER.
from their direction they are expected to coalesce below.
One of these presents a mass of ore 52 feet thick.
There are now in view, according to the report, thou-
sands of tons of ore.
The economy of freight is a matter of so much impor-
tance that the company has erected smelting furnaces at
the mine. Wood is the fuel employed and the furnaces
are on the reverberatory plan. The cost of smelting
for a year is estimated at $21,272, the products of the
furnaces for the same time being worth $67,742.
The capital stock of the company is $500,000 divided
into 10,000 shares. The proceeds of the year ending
March 21st, 1857, were 485 tons of ore averaging 23
per cent., 260 tons of regulus averaging 50 per cent,
and 3766 pounds of copper.
The Isabella Mine has stopped on account of pecuni-
ary difficulties. Its entire product has been estimated
at 4000 tons averaging 16 per cent. Professor Safford
states the production for September, 1855, at 120 tons
containing 29 per cent, of copper.
The Polk County Mine is engaged in a suit about the
title and has stopped in consequence. In September,
1855, according to the authority just quoted, it sent to
market 108 tons of ore of 29J per cent. Its entire pro-
duction has been stated to be about 2500 tons of ore
averaging 20 per cent.
The Mary's Mine has sent away about 1500 tons
averaging 28 per cent. Its monthy product is about
40 tons.
The London Mine has very rich ores, averaging
45 per cent. Its monthly product is stated at 40 tons.
MINES OF COPPER. 279
The Cocheco Mine has been till recently in litigation.
At present it promises well, the openings having exposed
a large amount of marketable ore.
GEORGIA. There are several localities in this state
which are thought to promise well for copper but I have
been able to obtain no definite information concerning
them.
The Canton Mine is chiefly valuable for its silver-
lead, but has produced also a remarkable ore of copper,
called by Professor Shepard, Harrisite. It is a pseudo-
morph of galena and is very rich in copper, containing,
according to Genth's analysis, nearly 78 per cent, of that
metal. The vein, according to Professor Shepard's re-
port, is a quartzy mica-slate, breaking into small blocks,
and containing galena, copper and iron pyrites, and re-
ceiving a dropper vein carrying gray ore. The capital
stock of the company is $960,000. They have already
taken out large quantities of ore, chiefly silver- lead.
They propose erecting a furnace at their mine, for the
separation of the silver and lead.
COPPER ORES IN THE NEW RED SANDSTONE.
The new red sandstone is a belt of rocks which follows
the flanks of the Appalachian chain, attaining its great-
est development in Connecticut and New Jersey, where
it is thirty miles wide. Throughout this range there
are numerous irruptions of trap and in the vicinity of
the junction of these two rocks the copper ores occur.
NEW ENGLAND. In Massachusetts copper ores have
been found, but have never been worked to any extent.
In Connecticut, in the eastern end of the town of Gran-
280 MINES OF COPPER.
by, are the Simsbury copper mines which were worked
in the early part of the last century. The company
was chartered in 1709, and appears to have been the
first incorporated mining company in the country. Ac-
cording to Professor Shepard, the ore occurs in beds,
nodules and strings, in a fine-grained, yellowish gray
sandstone. The principal ore is vitreous copper. A
good deal of ore was taken out at different times, but
about the middle of the last century, the mines were
abandoned and lay idle for forty years, after which they
were purchased by the State and used as a prison for
sixty years. In 1830 they again passed into the hands
of a company, were worked for a few years and finally
abandoned.
NEW JERSEY. Quite a number of openings have been
made in this State, and the carbonates, oxides and sul-
phurets of copper have been found in considerable quan-
tities, but not at any point in regular veins. For the follow-
ing history we depend chiefly upon Whitney's abstract,
and upon Rogers' report on the geology of New Jersey.
From 1748 to 1750, several lumps of native copper,
weighing in all over 200 pounds, were ploughed up in a
field belonging to Philip French, near New Brunswick.
A company was formed, and in 1751, a shaft was sunk
on a spot "where a neighbor, passing in the dark, had
observed a flame rising from the ground, nearly as large
as the body of a man." After a time, a sheet of copper
" somewhat thicker than gold-leaf," was found between
walls of loose sandstone. Lumps also varying from 5 to
30 pounds in weight were taken out. After following
the vein for 30 feet, the company abandoned their enter-
MINES OF COPPER. 281
prise on account of the difficulty of removing the water.
Meanwhile they had stamped out and sent to England
several tons of copper. It is said that sheets of copper
"of the thickness of two pennies and three feet square,"
were taken from between the rock, within four feet of
the surface.
The ScJiuyler Mine, near Belleville, in Essex county,
on the left bank of the Passaic, seven miles from Jersey
City, was discovered by Arent Schuyler, about 1719,
The ore was abundant near the surface and easily mined.
It was worked by the discoverer and his son, and before
the year 1731, 1386 tons of ore had been taken out and
sent to England. Li 1761, the mine was leased to a
company, which worked it for four years, and abandoned
it after their engine house had been set on fire by a dis-
charged workman. Several companies have spent a good
deal of money on it since the Revolution, but it has
never been profitably worked.
According to Professor Rogers' report, the principal
body of the ore is embedded in a stratum of sandstone
20 or 30 feet thick, dipping about 12 from the horizon,
rather by steps than regularly. It has been worked
212 feet below the surface and 150 feet horizontally
from the shafts. The ores are principally sulphurets
and carbonates of copper which are diffused through the
indurated sandstone. There is no trap exposed on the
surface anywhere in the immediate neighborhood.
At the Falls of Passaic, near Paterson, traces of cop-
per have been found, and fruitless excavations have been
made, in search of a regular vein. In the neighborhood
of New Brunswick, " prior to the revolutionary war, an
24*
282 MINES OF COPPER.
extensive and costly attempt was made to establish a
mine, but without success." There are blue and green
carbonates in the shale, and occasionally metallic copper
is found in the shape of a thin plate injected into the
body of the rock, which is hardened and changed from
red to gray in the immediate vicinity of the metal.
At the Franklin Mine near Griggstown, in Somerset
county, the ore is found in a shale altered by its proxi-
mity to trap. It is usually diffused, but sometimes oc-
curs in narrow short strings, mixed with crystalline
minerals. It has been worked to the depth of 100 feet
and drained by a long adit. Much money has been ex-
pended here without any return.
The Bridgewater Mine, at the base of the trap ridge,
north of Somerville, is another of these ruinous invest-
ments. As in all the others, the first openings were
very promising. Out of the altered shale were taken
quantities of red oxide of copper and native copper.
Of the latter, two masses weighing 1900 pounds, are
said to have been found in 1754. A smelting furnace
was erected by some Germans about the middle of the
last century, but soon abandoned. In 1824, the mine
was again opened and worked, and as before, money
was lost.
The Flemington Mine was the only one actually
worked at the date of Professor Rogers' report, (1836.)
He describes the ore as consisting of gray sulphuret
and carbonate of copper, intimately blended and incor-
porated with semi-indurated and altered sandstone, parts
of the mass having the appearance of a conglomerate of
recemented fragments. The metalliferous belt, some-
times twenty or thirty feet wide, preserves a north and
MINES OF COPPER. 283
south direction for several hundred feet. The ores are
mixed gray sulphurets and carbonates. They are of
very good quality. I find, by reference to my record
of analyses for 1849 and 1850, that commercial samples
of lots sent to Baltimore varied from 28 to 50 per cent.
An attempt was made at one time to smelt the ores on
the spot, but resulted in loss. Some of the slag, con-
taining 8 per cent, of copper, was sold in Baltimore.
The mine was finally abandoned, the metallic deposit
being too uncertain for profitable working. I visited
the mine in 1855, but was not able to go down into the
shafts, owing to the presence of water, and am conse-
quently unable, from personal observations, to add any-
thing to what has already been stated on the authority
of Whitney and Rogers.
"It would seem as if these failures might have been
sufficient to warn capitalists from wasting any more
money in these mines. The State Geologist, in his re-
port, remarks that there are no true veins in this for-
mation, and warns against further expenditures, unless
made with the greatest caution.
" Notwithstanding all this, New Jersey had, in 1846
and 1847, a little copper fever as well as Lake Superior.
In 1847, there were six mining companies organized in
this district, with 69,500 shares, and their market value
exceeded $1,000,000. The Raritan mine, three miles
southwest of New Brunswick, was purchased at a high
price, and large expenditures were made under the ad-
vice of Dr. C. T. Jackson and J. H. Blake, Esq.
The Passaic Mining company erected a steam engine
and expended a large sum of money, near the old Schuy-
ler mine. The Nechanic mine, near Flemington, which
284 MINES OF COPPER.
had been worked before the Revolution, was re-opened
at a considerable expense. The Washington mine, near
the old Bridgewater mine, at Somerville, was another of
these unfortunate concerns, in which the future profits
per acre were calculated to the fraction of a dollar.
"All these mines were abandoned, after heavy expen-
ditures, with almost total loss of the whole amount invest-
ed; and it is to be hoped that no more money will be
sunk in them."*
CUPRIFEROUS VEINS AT THE JUNCTION OF GNEISS AND
NEW RED SANDSTONE.
In Montgomery and Chester counties, Pennsylvania,
there is a metalliferous zone running east and west
across the Schuylkill river, occupying a belt of country
six or seven miles long, in the vicinity of Perkiomen and
Pickering creeks, not far from the junction of the gneiss
with the new red sandstone. Within this space are
some ten or twelve lodes, some of which are confined
entirely or chiefly to the gneiss, while others traverse
the red shale. The former bear lead as their principal
metal, while in the latter copper predominates. The
gneiss is much decomposed to a very considerable depth,
and is intersected by numerous dykes of granite, green-
stone, trap and other igneous rocks, which sometimes
cut the strata vertically and sometimes are parallel with
the planes of the enclosing rock.
The Perkiomen Consolidated Mining Company was
organized in 1851, by the consolidation of the Ecton and
Perkiomen mines, both of which were on the same lode,
their engine shafts being about 1800 feet apart. In
* Whitney. Op. tit.
MINES OF COPPER. 285
April, 1852, the report of the manager, C. M. Wheat-
ley, states that the engine shaft in the Perkiomen mine
was passing the 50 fathom level, and that the lode at
that depth, was from four to nine feet wide, made up of
quartz, gossan and sulphate of baryta, with green car-
bonate of copper and copper pyrites in place. It had
decidedly improved from the 40 fathom level down. At
the Ecton mine, the 54 fathom level was driving from
the engine shaft west, in a lode varying from two to five
feet in width, with good copper pyrites but not worth
stoping. In May, 1853, the Perkiomen's shaft is re-
ported to be 62 and the Ecton shaft 66 fathoms deep,
but the lode poor in ore in both mines. From August,
1851 to April, 1852, 524 tons of ore, varying from 7
to 23 per cent, of copper, were sold by this company,
for $30,573. In 1853, it is stated that the sales for the
year were 142 tons of ore for $9,989.
Since September 1853, the mine has not been raising
ores.
Ores have also been found in New Mexico and on the
Gadsden purchase. The Arizona mine, in the latter
tract, has sent to Baltimore and to Swansea very rich
ores containing some fine crystallizations of the red
oxide, but I have been unable to obtain satisfactory
information concerning the mine.
Copper ores are also said to abound about the head
waters of the Gila river, where several mines are report-
ed to have been worked. The most celebrated is that
of Santa Rita del Cobre, the ores of which are red oxyd
imbedded in a red feldspathic rock. A Frenchman who
worked it from 1828 to 1835, is said to have made half
a million of dollars from it.
CHAPTER V.
COPPER SMELTING.
THE object of smelting the ores of copper is, of course,
to obtain the metal in a state sufficiently pure for the
purposes of commerce. The degree of purity or fine-
ness required depends upon the use to which the copper
is to be put. For certain alloys it is not absolutely ne-
cessary that it should be perfectly malleable, while for
tubes, wire, or sheets, it must be thoroughly refined.
The processes for obtaining it vary greatly in different
countries, and depend entirely upon the nature of the
ores and the character of the fuel which is employed.
The simplest of these is that practiced upon the native
copper of Lake Superior.
SMELTING LAKE COPPER.
For the purpose of obtaining pure malleable copper
from the masses, stamp and barrel-work sent down from
the mines of Lake Superior, it is only necessary to sepa-
rate the earthy matter which still adheres to the metal,
and then to deprive the copper of the oxygen it has
absorbed while in the liquid state. The furnaces do not
differ materially from those to be presently described,
when we come to speak of the English method of smelt-
ing. They are reverberatories of an ordinary construc-
tion.
COPPER SMELTING. 287
Sometimes the whole process is conducted in a single
furnace. In this case the ore is charged into the fur-
nace, mixed with a flux adapted to the nature of the
earthy matter under treatment. The heat is kept up
till the whole is fused, when the copper, owing to its greater
specific gravity, sinks, while the liquid earthy matter or
slag floats upon its surface. This slag is now drawn off"
the face of the copper by means of rabbles, and the
metallic bath is exposed. During the fusion, the copper
has of course absorbed oxygen, which, if allowed to re-
main, would render the metal, to a great extent, fragile.
The surface is, therefore, covered with charcoal, and
rods of green wood are plunged into the metallic bath,
in order to reduce the oxide. The refining being com-
pleted, the metal is laded out, and poured into moulds.
At other times, two furnaces are used, and in that
case the metal is first obtained in the form of pigs, which
are afterwards refined. The slags taken from these fur-
naces are very rich in copper, containing numerous shots
and flakes of copper diffused through them. They are
therefore worked over again with an additional quan-
tity of flux, in order to obtain as much as possible of
this retained metal. Still the slag is found to contain
too much copper to be thrown away. In order to obtain
this, the slags are passed through a small cupola furnace.
The resulting slag may be considered clean, but there
has been an unavoidable waste of copper, which has vola-
tilized at the high heat of the cupola and passed out of
the chimney.
The establishments at which the lake copper is work-
ed, are at Detroit, Cleveland, and Pittsburgh.
288 COPPER SMELTING.
ENGLISH PROCESS OP COPPER SMELTING.
By far the largest amount of copper produced at any
one locality for smelting, is obtained from the copper
works of Swansea, in South Wales. Indeed the product
of those great furnaces is estimated at more than one
half of the entire world. The process there adopted is
a tedious and intricate one, but appears, on the whole,
the best adapted to a general smelting establishment.
It is undoubtedly susceptible of improvement, as it has
been recently estimated that not less than ten or twelve
per cent, of the entire yield of copper in Great Britain
and Ireland is lost in the smelting.
The average yield of the ores of British and Irish
mines sold in Swansea, may be estimated at 6.7 per cent.
The actual amount obtained from the furnaces does not
amount to more than 6 per cent., so that 0.7 per cent,
of the ore, or nearly 12 per cent, of the copper contain-
ed in it has disappeared. This statement, however,
probably does not accurately represent the actual loss.
Some of this has soaked into the bottoms, some has been
carried into the culvert, where it is not beyond the reach
of the smelter. Another portion, however, has gone
away in the slag, and as it cannot be profitably extract-
ed, it is irrecoverably lost.
To meet this loss, the smelters have adopted a series
of rules, which transfer it from their shoulders to those
of the miners. In the first place, the smelter's ton con-
sists of 21 hundred weights, or 2852 pounds, so that five
per cent, is gained here. Again, the ore is all bought
by the dry essay. This, as has already been said, is
never accurate, the loss being greater in the crucible
COPPER SMELTING. 289
than in the furnaces. This difference between the assay-
room and the works, increases in an inverse proportion
to the richness of the ore. Thus, in an ore ranging
from three to six per cent., the crucible loses at least
fifteen per cent, of the copper more than the furnaces,
while in one containing twenty-five per cent., the differ-
ence would not be more than five per cent. Besides
these, there are minor charges put upon the ore. Much
dissatifaction has for some time existed on the part of
the miners at these arrangements, but experience has
long since proved that they would lose far more if they un-
dertook to smelt for themselves. Independently of the
superior advantages which the smelters at Swansea enjoy,
in the proximity of coal, and the facilities for transpor-
tation, they can work cheaper than the miners, because
there is always a decided loss attending the attempt to
work one class of ores alone.
The rationale of the process adopted at Swansea will
be better understood after an acquaintance with the
character of the ores smelted there. These are divided
into five classes :
First Class. These consist almost entirely of copper
pyrites, containing a large proportion of iron in the
state of sulphuret, and mixed with much mundick or iron
pyrites. They contain little or no carbonate or oxide
of copper. The earthy and silicious ingredients are in
large proportion, so that the amount of copper ranges
from three to sixteen per cent.
Second Glass. Resembles the first, with the difference
that they are richer, containing from fifteen to twenty-
five per cent, of copper.
25
290 COPPER SMELTING.
Third Class. Copper pyrites containing but little
iron pyrites or other substance likely to impoverish the
metal produced, and having a large proportion of oxidiz-
ed ores of copper.
Fourth Class. The basis of these ores is usually
/ quartz. They contain from twenty to thirty per cent,
of copper in the form of oxide and carbonate, mixed
with some sulphuret.
Fifth Class. Rich ores from Chili or South Austra-
lia, containing often eighty per cent, of copper, in the
form usually of carbonate or red oxide. The gangues
are commonly silicious.
It is evident that the object to be attained is the libe-
ration of the copper, not only from the earthy matters
in which its ores are imbedded, but also from the sulphur,
oxygen and iron with which it is chemically combined.
These results are arrived at by a series of calcinations
and smeltings, which vary with the ore under treatment.
M. Le Play has classified these various processes under
ten heads, and we shall follow his order in describing
them.
I. Calcination of the ores of the first and second class
to expel sulphur.
II. Melting the calcined with raw or unburnt ore, to
separate the earthy matters and to obtain a matt or coarse
metal.
III. Calcination of the coarse metal still further to
expel sulphur.
IV. Fusion of the calcined metal with rich ores of
the fourth class, to get rid of iron and obtain white
metal.
COPPER SMELTING. 291
V. Melting for blue metal, or fusion of the calcined
coarse metal with roasted ore, moderately rich in cop-
per.
VI. Re-melting of rich slags to recover the copper
contained in them.
VII. Roasting for white metal, or production of white
metal of extra quality. This operation sometimes in-
cludes the roasting of the blue metal obtained in process
V.
VIII. Roasting for regulus.
IX. Preparation of crude copper, by roasting and
melting white metal, regulus, &c.
X. Refining and production of tough malleable copper.
The furnaces in which these operations are performed
are all of the reverberatory form, but differ in their di-
mensions and the slope of the roof. In well-conducted
establishments, they are all connected with an under-
ground culvert in which volatilized copper is arrested and
recovered.
The calciner, in which the first operation is more spa-
cious than the others. The hearth, or laboratory of the
furnace, is elliptical in form, truncated at the extremi-
ties of its long axis, and having, between the openings
through which the charge is removed, angular projec-
tions towards the centre of the bed. It is sixteen feet
long, and thirteen and a half wide. It is formed of
fire-bricks set on edge, and firmly bedded in refractory
fire clay. Each of its sides is provided with two work-
ing doors, through which the various operations of stir-
ring and raking down the ore are performed. Imme-
diately within each of these doors, is an opening through
COPPER SMELTING.
,
PLAN OF CALCINING FURNACE.
R, Sole of furnace. F, Fireplace, a a, Side or working doors, e e e e. Openings
communicating with the vault, d, Special air-hole, which can be opened or closed
at pleasure. H H, Flues.
which the calcined charge is raked down into the arched
chambers beneath. While the calcination is going on,
these are kept closed by iron plates which are removed
at the close of the operation, to admit of the removal of
the roasted ores. The arch, which has a mean height of
two feet above the sole, descends rapidly from the fire-
place to the flue-holes, at the other end of the long axis,
through which the gases escape into the chimney. A
current of cold air is admitted by an opening near the
fire-place, which can be closed at pleasure. In some
COPPER SMELTING.
293
forms of the furnace, a channel is made in the fire-
bridge, through which passes a current of air having
the advantage of being heated, and consequently more
active.
Fia. 10.
CALCINING FURNACE. SECTION.
A B, Level of sole. C, Vault into which the calcined ore is raked. H, Flue. E,
Sole of furnace, a a, Working doors. S S, Hoppers.
The arch of the furnace supports two large hoppers
of sheet iron, provided with sliding doors at the bottom.
Into these the ore is placed, and allowed to drop into
the furnace on the removal of the slides. Outside, the
furnace is bound together by strong iron bands, arranged
both perpendicularly and horizontally.
The coal used in the Swansea works is anthracite, the
combustion of which presents many difficulties to be
overcome by the smelter. It ignites slowly and imper-
fectly, and on being heated flies into powder, which
either falls through the bars, or accumulates and chokes
25*
294 COPPER SMELTING.
the draught. Besides, it produces a fusible ash, which,
at a high temperature, runs into a glassy slag, that not
only chokes the draught, but rapidly corrodes the bars
of the grate.
To obviate these difficulties, the smelter has recourse
to very simple methods. He places his grate-bars wide
apart, and throws pieces of scoria loosely upon them
till he has formed a layer about a foot thick. Upon
these the fire is made, and the ashes accumulate. They
all fuse together to a spongy silicious mass, everywhere
traversed by a great number of apertures. As this
matter accumulates, the fireman, from time to time, de-
taches the lower portion and allows it to fall into the
hearth. Thus he has a grate formed of slag, containing
interstices too small to permit the fragments to fall
through, and yet sufficient for a draught. The gases
arising from this combustion consist chiefly of carbonic
oxide, which passes over the fire-bridge into the body of
the furnace. Here it meets the stream of air introduced
through the openings already mentioned, and others
which are left in the iron-plates closing the lateral open-
ings. Thus the whole cavity of the furnace is always
filled with flame, caused by the carbonic oxide burning
as it comes in contact with the atmosphere. The mine-
rals spread over the sole, are, therefore, exposed to a
current of air, above which is a parallel sheet of car-
bonic oxide, burning on its under surface where it comes
in contact with the oxidizing stratum, and so affording
sufficient heat to conduct the entire operation.
The charge, which consists of three or three and a
half tons, is introduced without any intermission in the
action of the furnace, by simply withdrawing the slides
COPPER SMELTING. 295
at the bottom of the hoppers. As soon as it has been
let down, it is spread evenly over the furnace bottom by
means of long iron rakes introduced through the work-
ing doors, which are then immediately closed. The fire
is then replenished with the proper amount of coal, the
cinders loosened, and the heat gradually raised. The
object of this process is to get rid of a certain amount
of sulphur ; but, in order to accomplish this, great care
is necessary. If the heat be pushed too rapidly at first
the ore will agglutinate, thus shielding a portion of it
from the influence of the air, and impairing the result,
besides obstructing the walls and sole of the furnace by
collections of fused sulphuret. After six or eight hours,
the heat may be raised, as then much of the sulphur has
been expelled, and the disposition to agglutinate is less.
At first, watery vapor passes off, and then sulphurous
acid. To facilitjite_Jjia action by exposing fresh sur-
faces to the action of the oxidizing agents, the charge is
stirred every two hours, by a long iron tool called a
rabble, till no more volatile products pass off, or until
the peculiar stage of oxidation demanded by the con-
dition of the ore, and exigencies of the other furnaces is i
attained. Towards the close of the operation, the heat is
pushed, and the furnace raised to its highest temperature.
The iron-plates covering the openings behind the doors
are then removed, and the calcined ore raked down into
the chambers below. This is a trying operation to the
workman, as the unpleasant effects of the heat are in-
creased by the fumes of sulphurous and sulphuric, and
often of arsenious acid, which arise from this glowing
mass. These are caused by the presentation of a greater
surface to the action of fresh air, which evolves still
296
COPPER SMELTING.
0.374
22.710
22.442
1.001
0.608
more gas than was expelled in the furnace. Imme-
diately after the removal of one charge, another is intro-
duced. The time occupied by this operation is usually
twelve hours, though it sometimes reaches twenty-four.
Little or no loss in weight is sustained in calcination,
as the sulphur expelled is substituted by oxygen ab-
sorbed. M. Le Play, who carefully examined these ope-
rations, has given the following tables of the ore before
and after calcination, which show the chemical changes
it has undergone.
BEFORE CALCINATION.
Oxide of copper, isolated or combined, ....
Copper pyrites, ........
Iron pyrites, bisulphide of iron, .....
Various sulphides, ........
Oxide of iron, .... .....
Other oxides, .........
Quartz and silica, ........ 34.428
Earthy bases, ......... 1.871
Water and carbonic acid in combination, . . . 0.491
Oxygen consumed, ........ 15.806
........... 100.000
AFTER CALCINATION.
Oxide of copper, ........ 5.401
Copper pyrites, . . ...... 11.228
Bisulphide of iron, . . . . . . . . 11.226
Other sulphides, ......... 600
Ferric oxide, ......... 11.718
Other oxides, .......... 608
Sulphuric acid in combination, ..... 1.108
Quartz and silica, ........ 34.408
Earthy bases, .. ........ 1.874
Gaseous products, / Sulphurous acid, . . . .21.338
I Water and carbonic acid, . . 0.491
100.000
COPPER SMELTING. 297
In these tables, no account is taken of the arsenical pro-
ducts which are scarcely ever absent. The matters escap-
ing from a calcining furnace may be said to consist of
Vapor of water,
Sulphurous and sulphuric acids,
Arsenious acid, and arsenical vapors,
Fluoride of silicium, and other volatile compounds of
fluorine, -
Solid matter, mechanically conveyed by the draught
into the flue,
Carbonic acid, &c.
The water comes from the oxidation of the hydrogen
of the coal, as well as from the moisture contained in
the ore. Coming in contact with the sulphurous acid,
it gives rise to sulphuric acid. The fluoride of silicium
results from the action of the silicious gangue upon the
fluor spar (fluoride of calcium) contained in the ore.
The rest of the volatile products need no particular
explanation.
All the vapors pass off into the atmosphere, and from
their enormous quantity, exert the most unfavorable
influence upon vegetation. Not a blade of grass can
grow for a considerable distance around Swansea, in the
direction of the prevailing winds, so that the smelters
are obliged to incur the expense of buying up large
tracts which they do not want and cannot use. The
curse of absolute sterility rests upon the environs of the
furnaces, and this will surprise no one who has ascer-
tained, by a simple calculation, that the amount of sul-
phurous and sulphuric acids given off from the numerous
chimneys of Swansea, cannot be less than ninety thou-
298 COPPER SMELTING.
sand or one hundred thousand tons. The loss has not
been confined to the agriculture of the district alone ;
the smelters have also suffered. The sulphur, volatil-
ized, is worth .120,000 a year, and if estimated as
common commercial sulphuric acid, to which condition
it could be easily reduced, it would afford an annual
revenue of 450,000.
Some attempts have been made to get rid of the poi-
sonous fumes. At first it was thought that, by erecting
very tall chimneys, these vapors would be mingled with
a large bulk of air, and so neutralized by the ammonia,
as to be rendered comparatively inert. Again, it was
attempted to build vitriol chambers in connection with
the shaft. Another plan was to conduct the volatile
matters through long galleries or troughs holding water,
and covered by perforated slabs of stone placed horizon-
tally, over which a stream of water was kept constantly
flowing. In these troughs, they meet the percolating
water which absorbs much of the sulphuric acid. The
difficulty, however, was that the presence of so much
liquid interfered with the draught, so that the measure
was abandoned.
Second Operation. The ore, being cooled, is wheeled
in barrows to the next furnace, in which the first smelt-
ing is performed. The object is to separate as much as
possible of the iron and all of the earthy matters. The
temperature employed is higher, and the charge much
less, than in the preceding operation. The iron enters
into combination with the silica, forming a fusible slag,
and though there is usually enough silica to combine
with the iron, it is customary to add a slag rich in cop-
COPPER SMELTING. 299
per, from one of the other furnaces, in order to effect a
more thorough combination. As the slags from this
process are usually rejected, it is important to have them
as clean as possible. There is always, however, a por-
tion of it which contains a little copper mechanically
mixed with the scoriae, which is sent back to the furnace
to be worked over. The residue, which is called " clean
slag," is thrown away, or employed to make roads, to
raise the grade of the yards, to lay the foundations of
other furnaces, &c. In spite of all the uses which have
been found for it, however, it becomes quite a serious
matter at Swansea to determine how it shall be dis-
posed of. Beginning near the furnaces, and gradually
going further and further, the smelters have surrounded
their works -with hills of refuse. Of late, it has been
the practice of some of the establishments to form the
rejected slag into tiles, slabs, and bricks, suitable for
building.
There is always a little loss of metal in this slag,
which is generally estimated at from four to five-tenths of
one per cent, of the entire metal contained in the ore.
It can, however, with care be reduced to two or three-
tenths, though this is by no means common.
The furnace in which this operation is performed, is
not more than one-third the size of the calciner. In
most furnaces it is charged through the top, and conse-
quently needs no side-door ; but in some, it is provided
with one side-door, through which the charge is intro-
duced. At the opposite side of the furnace is an open-
ing, called the tap-hole, through which the molten metal
is allowed to flow out. The bottom is made of a refrac-
tory sand, which is agglutinated by heat, before the
300
COPPER SMELTING.
FIG. 11.
SMELTING FURNACE PLAN.
A Sole of furnace. B, Depression for the accumulation of metal. F, Fire-place.
MMMM, Sand moulds for slag. V, Water tank. W, Winch for raising from fur-
nace.
a a Outlet for melted metal, d Working door for draining off slag.
charge is introduced. It is depressed towards the tap-
hole, to allow the molten metal to flow out readily, and
so worked as to form a sort of basin immediately within
that opening. In front of the furnace is a door, through
which the scoriae are raked out, the ore stirred, and the
various repairs of the furnace bottom accomplished.
Immediately below this door, outside of the furnace, are
sand-moulds to receive the fluid slag, which is withdrawn
from the surface of the metal. Near the tap-hole is
usually a tank of water, with an iron pot on the bot-
COPPER SMELTING.
301
torn, which may be lifted out by a crane. In this, the
metal tapped out from the furnace, becomes granulated.
The fire-place is larger in proportion to the size of the
furnace than in the calciner. Its dimensions are about
four feet by three and a half, while that of the bed of
the furnace are only about eleven by seven. The fire
is made as usual, but at Swansea about one-third of bitu-
minous coal is added to the anthracite for the purpose
of obtaining a hotter fire than the calciner can furnish,
the greater heat being needed for the fusion of the sub-
stances.
FIG. 12.
SMELTING FURNACE SECTION.
H. Hopper for charging. M, The other letters hare the same reference as in the
preceding figure.
The charge usually consists of seventeen or eighteen
hundred weight of calcined and two or three hundred
weight of crude ore of the third class. To these are
26
302 COPPER SMELTING.
added three and a half hundred weight of slag contain-
ing copper, and obtained from operations IV., V., and
VII. These subserve the double purpose of rendering
the slag more fusible, and of giving up to the metal the
copper they contain. The ore and the finer portion of
the flux are introduced through the hopper, and the
coarser portions of the latter are thrown in at the door.
This is quickly spread upon the bed of the furnace, and
the larger pieces of slag are then thrown in. The
charge having been introduced, the door is closed and
luted, and the tap-hole blocked up with sand and scoriae.
The fire is then pushed, and the charge remains undis-
turbed for about three hours and a half, except for the
necessary examination of the process. Fresh fuel is
thrown on at the end of an hour and a quarter, or
thereabouts. This furnace consumes about thirty-four
and a half hundred weight of coal in the twelve hours.
The first effect of the heat becomes manifest in about
half an hour after the spreading of the ore on the
hearth of the furnace. The slag then begins to melt
and form little pools or channels full of liquids. Soon
after, the fluid mattter begins to extend over the hearth,
in consequence of the formation of a fusible silicate by
the iron and silicic acid present in the ores and slags.
As the quantity of liquid matter increases, it is agitated
by the evolution of sulphurous acid gas, formed at the
expense of the sulphuret of iron, which becomes oxidized,
and combines with the silica. Fluor spar greatly assists
these actions, its fluorine entering into combination with
the silica, and forming a volatile compound which carries
off arsenic. At the end of the three hours and a half, the
COPPER SMELTING. 303
charge is nearly melted. The furnace man now opens the
door, and by means of a long rabble, stirs it, bringing
the unmelted portions more directly in contact with the
fused mass, and causing it to fuse. The heat is now
increased, and kept high till the fusion is completed.
The molten bath is now divisible into two layers, the
upper containing the earthy, and the lower the metallic
contents of the ore. The former of these is now re-
moved through the front door by a process of rabbling.
In some instances, a new charge is now thrown in on
top of the bath, to increase the metallic yield of the fur-
nace, but usually the " coarse metal," as it is called, is
tapped out, and a fresh charge introduced afterwards.
The separation of the slag from the metal is never
perfect. A little copper is always found in the lower
layer of liquid. Most of this subsides to the bottom of
the central pig of slag, which is kept liquid by the con-
tinual addition of fresh molten matter from the furnace.
What is not arrested by this plate slag, passes over
to those on either side of it. The quantity of metal
contained in these slags, varies with many circumstan-
ces. Thus, if the matt be very poor, and the slag of
nearly the same degree of fluidity with the metallic
bath on which it rests, there will be more metal mechan-
ically mixed with it than if the matt were heavier, or
the difference in the fluidity of these two superimposed
baths greater. The cleanliness of a slag depends upon
a proper adjustment of all these particulars, and re-
quires no little skill and experience for its accomplish-
ment.
The slag, having cooled sufficiently, is wheeled out to
the heap, where it is broken up and examined. Those
304 COPPER SMELTING.
fragments which contain metal, are sent back for re-
smelting with the next charge. It is no easy matter to
attain the exact composition of a charge to produce the
best effect. The most important point is to make such
a fusible mixture that the matt may subside by reason
of its greater specific gravity, and separate exactly from
the slag. This is greatly assisted by the oxide of iron
in the scoriae of the fourth operation, which are, as we
have already said, added to the charge. Much, also,
depends upon the admixture of earthy matters in the
ores. The best results are obtained when these are so
proportioned as to form a highly crystalline slag. In
practice, it is customary to make several trials with dif-
ferent combinations of the ores in the yard, until such
a mixture is hit upon. After that, nothing is required
but toTollow the routine" thus established. When the
variety of ores is large, the simplest plan is to mix the
poor and rich ores in such proportions as to obtain the
average per centage of the matt, when the various earths
in combination with the different ores flux one another,
and give the desired result. It is, however, evidently
not always possible to do this. In cases of difficulty,
the usual practice is to make a full quantitative analysis
of the ores, and to construct a proper mixture by the
light thus afforded. It may happen that this reveals
the fact that the ores alone will not produce a fusible
mixture. In this case, fluor spar or limestone is added ;
but it is desirable to avoid this, if possible, as, if too great
a quantity of slag be made, a corresponding loss of cop-
per will be sustained by the mechanical retention of
minute particles of metal.
The man who superintends this operation is called
COPPER SMELTING. 305
the roaster-man, and much depends upon his skill and
knowledge of the working of the furnace. He deter-
mines the heat by inspecting the interior of the furnace,
through a hole in the tile which closes the door, to ascer-
tain if it has reached the proper degree of incandescence.
If it be not hot enough, the fire is examined to deter-
mine whether the fuel be excessive or insufficient, and
whether the draught be strong enough, and the defect,
when ascertained, is immediately remedied. It is impor-
tant to regulate the quantity of air passing through the
furnace. If this be too great that is, more than suffi-
cient for the combustion it shortens the flame and di-
minishes the heat.
Four hours are required to work off each charge, so
that this about balances the calciner, which, though
much larger, requires much longer time to do its work.
The heat must be kept up during these four hours, in
order to keep the contents of the furnace in perfect
fusion. If this is not done, the ore may adhere to the
bottom. At the end of the heat, the slag is skimmed
off, as already described, and the furnace tapped. The
entire amount of slag is not, however, removed, as, in
that event, the matt would be covered with a layer of
oxide of copper, which would diminish its fluidity, and
render it difficult to flow out from the furnace. A little
slag is also left in the furnace, to obviate the corrosive
action of the ore upon the hearth. The matt is usually
allowed to flow into the tank of water already described,
where it is granulated. As soon as it is cooled suffi-
ciently, it is raised out of the tank*and removed to the
storehouse, to await the next operation. When it has
26*
306 COPPER SMELTING.
all flowed out, or sometimes while it is still running
from the furnace, a fresh charge is introduced, which is
worked in precisely the same way.
Two men at a time manage this furnace, which works
day and night throughout the week. Each pair of men
has charge of it during twelve hours. On Saturday
night, the furnace is put on what is called "dead fire,"
for Sunday that is, it is merely kept hot, without being
charged with fresh ore. On Monday morning, or Sun-
day night, according to the regulations of the works,
it is again charged and kept at work for another week.
The night work is taken alternately by the men, who
are paid by the ton, and are not allowed anything for
working over their foul slag.
The chemistry of these operations is very simple. The
principal change which takes place is the formation of a
silicate of iron and the expulsion of sulphur. There is
usually enough silica in the ores to take up as much of
the iron as is desired. When this is not the case, quartz
sand is added. Iron has a strong tendency to unite with
silicic acid at high temperatures, especially when the
oxide is brought into intimate admixture with silica by
means of a fusible flux. Silicate of iron and fluor spar
combined, answer this purpose admirably well. The
oxygen gas of the air passing over the fused materials
burns off the sulphur, and converts the iron into an oxide
which unites with the silicic acid. The evolution of gases
causes a commotion which greatly facilitates the opera-
tion. Fluor spar acts by parting with its fluorine to sili-
ca which should be in excess, forming volatile flouride of
silicium, which bubbles up through the mass. It mixes
the materials well, and renders the slag fluid by the for-
COPPER SMELTING. 307
mation of another silicate, that of lime, thus preventing
the stiffening of the slags by an excess of silica. It gets
rid of this excess by removing a portion of it directly,
in a volatile gas, and by forming a fusible silicate with
another portion. Limestone acts only in the latter way.
It is evident that both are useful chiefly where there is
too much silica for the iron.
The resulting matt is a mixture of sulphuret and a
little oxide of jcppper with sulphuret of iron and small
quantities of other metals. The earthy matters, some
of the sulphur, and much of the iron have been separated
in the slag or the volatile products.
Third Operation. The granulated matt is charged
into a furnace precisely similar to that used for calcining
the ore. Care is taken to prevent the fusion of the matt,
which would prevent the proper action of the air. For
this reason, the heat is kept down at first and gradually
pushed towards the close of the operation, which lasts
about twenty-four hours. During this time, the matt is
rabbled every two hours in order to change the surfaces
and expose the sulphurets freely to the action of the
atmosphere. At the close of the operation, the furnace
should have attained a bright red heat. To effect this
roasting, thirty-three hundred weight of coal are used.
The metal has now changed from a dark, reddish gray
to a brownish black, and has become more friable. The
chemical alteration consists in the further oxidation of
the metals and the expulsion of still more sulphur. The
loss of weight is not considerable, because oxygen has,
to a great extent, taken the place of sulphur. Thus,
1000 parts of crude metal will furnish 974 of calcined
metal, and 270 of sulphurous and sulphuric acids.
308 COPPER SMELTING.
Fourth Operation. The object of this operation, which
is performed upon the calcined coarse metal, is to sepa-
rate, as far as possible, the iron from the sulphuret of
copper. It is usually, however, not confined to this
simple and direct melting, but advantage is taken of it
to work down other ores of the fourth class, which con-
tain little sulphide of iron, and are rich in copper in
the state of sulphide and oxide, as well as the rich scoriae
from the upper furnaces. It requires no little skill so to
blend the heterogeneous materials of this charge as to
produce a satisfactory result. There are smelted in this
furnace, not only the calcined metals, rich ores, and
scoriae, but also the various sandy and calcareous mat-
ters from the walls and soles of furnaces which may have
become impregnated with copper. The table will give
some idea of their usual proportions :
Calcined coarse metal from the third operation, . 559
Crude ores, 243
Copper scales from the rolling mills, &c., . . 7
Scoria from the ninth operation, ... 60
Scoria from the tenth operation, ... 24
Furnace waste (cobbing) from the second to the
tenth operations, ..... 60
Earthy matters, sand impregnated with copper, . 41
Earthy matters, bricks impregnated with copper, 6
1000
It will be understood, of course, that this table is intend-
ed to give merely an approximate idea of these propor-
tions, as it is very evident that the working of substances
COPPER SMELTING. 309
so very various in their composition and metallic con-
tents, cannot be carried on by any fixed formula, but
must vary with their changing constitution. The crite-
rion for the workman is the practical result of the first
charge. He may succeed in getting a fine sulphuret of
copper with a comparatively clean slag at the first trial,
but he may, on the other hand, produce a metal con-
taining a large proportion of sulphuret of iron, and a
slag in which there is a good deal of oxide of copper.
It is generally believed that the best results are attained
where there remains in the matt a little iron, say from
four to ten per cent., and from three to five per cent, of
copper pass off in the slag. This does not interfere with
the success of the work, as these slags are all smelted
over again in the lower furnaces, where the copper is re-
covered. It is, however, necessary to guard against an
excess of this oxide of copper in the slag, as it will re-
act upon the sulphuret and produce metallic copper,
which is not desirable at this stage of the process, since
it would deteriorate the product.
The furnace in which these operations are performed,
resembles that devoted to the second fusion, except that
there is no cavity in the hearth, but a gentle slope to-
wards the side at which the fused material is run out.
The fire is managed in the same way, but the heat is
greater on account of the greater consumption of fuel.
The materials are introduced either through the hopper
or the side-door, the larger portions, especially the sco-
riae being thrown through the door. They are then
spread evenly over the sole of the furnace. The charge
weighs about thirty-two hundred weight.
310 COPPER SMELTING.
The doors are now closed and luted, and the fires
regulated so as to calcine the surface. In about an hour
the mass begins to soften and evolve a good deal of gas,
arising from double decomposition, and in about three
hours after charging, the fusion is nearly completed,
the furnace presenting the appearance of a bath upon
which the unmelted matter floats. In about four hours
from the time of charging, the matter adhering to the
walls of the furnace is raked down and the whole mass
well rabbled. In a short time, the fire being pushed,
the contents of the furnace are in a state of tranquil
fusion. The heat is still gradually raised until the metal
is thought to be sufficiently purified, which generally
happens in about six hours from the time of charging.
The scoriae are raked off by the front door, and the fluid
matt tapped out at the side, either into sand moulds
where it is cast into pigs, or into a cistern to be granu-
lated.
The results of this operation are a white metal, which
contains but little foreign matter, being a nearly pure
sulphuret of copper, and slags or scoriae which are brittle
and crystalline, and contain, as already stated, some
oxide of copper. In Swansea, a special operation is re-
sorted to for the purpose of recovering the copper con-
tained in these scoriae. They are broken to pieces and
divided in two lots, of which the poorer is worked in the
first fusion, while the richer, being mixed with pulveriz-
ed coal, are melted to obtain their metal, which is white
and brittle. The scoriae resulting from this special melt-
ing are partly thrown away and partly employed in the
first fusion.
COPPER SMELTING. 311
The products of the fourth operation have been stated
in the following manner :
White metal, .... 402
Poor slag, 261
Rich slag, 281
Furnace waste, ... 9
Sulphurous acid, ... 43
Water and Carbonic acid, 4
1000
The white metal is grayish white or blueish, with a
strong metallic lustre, containing many small cavities
which are often lined with copper. Its composition is :
Copper, . . .73.
Iron, .... 6.5
Sulphur, . . . 20.5
100.0
Sometimes there is only fifty per cent, of copper in it,
but this is below the standard.
Fifth Operation. The usual routine hitherto followed
in the several processes, in dealing with the ore, is in-
terrupted here, and the product of the fourth fusion is
not used, but only substances of a different nature and
class, hence, to tabulate the course of procedure in the
way in which the above order indicates, would appear
contradictory and confusing ; but it is customary in the
copper foundries of Swansea, to adopt this plan of work-
ing fresh materials with the slag and various other mat-
ters containing copper, and to bring the valuable matter
312 COPPER SMELTING.
in them into a fit state to undergo the same operation as the
product resulting from the last fusion, an operation to
be described under the ninth stage. There is another
purpose in view and this is the production of a better
quality of copper. Rich foreign ores and matt which
are imported into Swansea, if mixed with the ordinary
productions of Cornwall, would give a metal only of
medium quality, having some good but many bad quali-
ties. It is the practice, in these cases, to work only the
copper ores which are free from the more difficultly eradi-
cated impurities, and for this purpose the intermediate
fifth, sixth, seventh and eighth operations are added to
remove the copper from the ore and the slags formed in
the state of white or blue metal. Three of these, the
fifth, seventh and eighth, are grouped together under the
designation of the extra process, to distinguish them from
the ordinary course, which would link the fourth and
ninth operations together. Both are, however, intimately
connected in more ways than one ; for instance, the ma-
terial used is identical with the product of the second
fusion or coarse metal ; this union is brought closer by
the use of the richer slags from the last operation.
When they have undergone another fusion, the result-
ing matt of white metal is submitted to the seventh and
eighth fusions, as well as that derived from the extra
product of the fusion under consideration, and the whole
is treated in the ninth operation indiscriminately. Indeed
these several stages for enriching the matt, although
they bring about reactions more efficacious towards re-
moving the substances which might deteriorate the cop-
per than the fusion in the fourth one, still are nearly
COPPEK SMELTING. 313
identical with the latter and with the ninth operation yet
to be described. This is especially the case in regard to
the fifth fusion, which is only a modification of the pre-
ceding one, and the roasting in number seven and eight
are merely repetitions of the ninth method.
The material employed here is, as already stated,
chiefly composed of calcined matt from the purer
variety of ores ; but, in general, a quantity of the ordi-
nary substance resulting from the second calcination, is
taken and incorporated with other materials, in the
annexed ratio :
Calcined coarse metal from third operation, 0.722
Calcined ore of the second or third class, . 0.185
Earthy matter silicious, . . . 0.084
" " bricks, .... 0.009
1.000
The furnace in which the process is conducted, is
identical in form with that used for the last fusion; if
the composition of fuel is in this as in the foregoing,
composed of anthracite and caking coal. The time
occupied in working the charge is about six to seven
hours, making twenty-two charges per week. Like the
substances used in the fourth operation, these undergo
a gradual fusion, which, toward the close, becomes urged
by a very high heat. Very little change is exerted till
the matter becomes liquefied, when the oxide of copper
reacts upon the sulphides of iron, giving rise to a sul-
phide of copper and an oxide of iron, which enters into
combination with the silicious matter, and generates a
27
314 COPPER SMELTING.
very fusible scoria. Sulphurous and sulphuric acids are
likewise liberated: but a portion of the sulphur is sub-
stituted for the oxygen derived from the oxide of copper,
thus converting the whole of the latter into a sulphide.
This constitutes the refining process which is chiefly
intended in this operation, namely, the removal of the
iron and excess of sulphur, leaving the copper combined
with the least quantity of the latter element. The weight
of the charge is two tons ; and the results after the fusion
may be expressed as in the annexed table :
Blue metal for the seventh operation, . 0.495
Scoria for the second operation, . . 0.434
Furnace waste for the fourth operation, . 0.008
Sulphurous acid, ..... 0.056
Oxygen, 0.007
1.000
After the charge is worked off, the matter closing the
tap-hole is completely removed, and the cupreous fluid
which is called blue metal, permitted to flow out into
moulds. The slag is then permitted to run out of the
same orifice.
Sixth Operation. In this stage, the slags resulting
from the preceding and the two succeeding fusions, and
which are rich in oxide of copper, as well as some rich
sulphide of copper from certain ores, which, however,
are free from injurious substances, are treated. The
furnace in this case is slightly modified to suit the
material which is being operated upon. No hopper is
appended, in consequence of the substance being in too
COPPER SMELTING. 315
large pieces to conveniently pass through ; but a charg-
ing door is formed in one side ; and when the lumps of
scoria are injected, very little exertion is required to
spread them evenly over the sole of the furnace. During
the succeeding treatment, this door is kept closed and
luted at the sides, so that no air can enter. When the
matt is ready, it is drawn off, as usual, through an ori-
fice for the purpose, made at the extremity of the trans-
verse diameter of the hearth, opposite the side in which
the charging takes place. The medium of heat is the
same in this as in the other furnaces, and the time occu-
pied in working extends to about five hours and a half.
As the quantity of oxide of copper in the scoria employed
cannot be wholly converted into sulphide of copper by the
action of the sulphur combined with the iron in the ore
added, it is reduced to the metallic state, and afterwards
purified in the succeeding treatments. This is brought
about by adding to the substance slack, or ground coal
or charcoal; the results of this reaction are carbonic
acid and metallic copper, which, owing to its greater
gravity, penetrates the scoria and matt, and forms a
layer of impure black copper, or bottoms, on the hearth.
In this behaviour the reduced metal effects an important
part in purifying the matt of sulphide of copper ; for it
reduces and precipitates with it certain portions of tin
and arsenic which are present, the removal of which
would otherwise be difficult, and the presence of which
would operate deleteriously upon the quality of the
metal. The nickel and cobalt which sometimes exist in
cupreous minerals are in like manner decomposed and
carried down in the black copper, their sulphur being
316
COPPER SMELTING.
transferred to a portion of the oxide of copper in the
slag. A product of great excellence is the result of
these various depurating reactions, and is called by way
of distinction, best selected, when it is reduced, and while
in the state of matt, hard metal.
In the charge for this furnace, which amounts gene-
rally to two tons, the several substances are taken in
the proportion of the annexed table, or thereabouts, viz :
Rich slag from the fourth operation, . 0.671
" " seventh " . . 0.095
" " eighth " . . 0.053
Copper pyrites, 0.079
Sweeping of the foundries from the eighth,
ninth, and tenth operations, . . . 0.055
Carbon employed as re-agent, . . . 0.001
Earthy matters sand, .... 0.036
" * " brick, .... 0.010
1.000
Details of working similar to those pursued in the
fourth fusion, onlyM;hat the hearth of the furnace is in
this instance more liable to corrosion, because sulphurous
products are in much less abundance, and the scoria and
iron react upon it, abstracting the silica. Such is the
case, especially in the parts adjoining the walls ; but as
a preventive, the slag is piled round in these parts, and
as soon as the matter becomes molten, the quartz, which
forms a considerable part of the ore added, supplies sili-
ceous matter to the iron, and the hearth is preserved.
At the close of the process, the fused matter is
COPPER SMELTING. 317
three layers ; the upper is constituted of the scoria, the
middle of fused matt, and the lower of black copper:
these are drawn off as usual. These products may be
tabulated as under
White metal for the eighth operation, . 0.057
Red metal " " 0.016
Tin alloy, 0.005
Copper bases for operation, . . . 0.008
Slag to be rejected, .... 0.901
Refuse of furnace for fourth operation, . 0.006
Carbonic acid, 0.003
Water and carbonic acid from ore, . . 0.001
1.000
Seventh Operation. Blue metal is here converted
into white metal, by the agency of the air; and the
chief or entire part of the remaining iron is removed,
by forming a fusible silicate towards the close of the
calcination. The furnace which is requisite for this
double purpose is constructed like that mentioned under
the last stage, with charging doors at the side and end,
opposite the fire, and a tap-hole at the other side at the
end of the middle transverse diameter. In addition to
these air is admitted by openings near or through the
bridge of the hearth, as already described in reference
to operations for roasting. Crude blue metal constitutes
the charge ; but it carries with it a certain quantity of
sand from the moulds wherein it was cast, and during
the working near a ton of the materials of the furnace
are disintegrated and carried off in combination, partly
27*
318 COPPER SMELTING.
with the iron of the scoria, so that the components of
the charge may be represented in the relative propor-
tion expressed by the annexed table, viz :
Blue metal from fifth operation, . . 0.789
Furnace waste, &c. sand, . . . 0.108
" " bricks and clay, . 0.006
Oxygen derived from the air, . . . 0.097
1.000
Two tons of the blue metal, or sulphide, are intro-
duced carefully at the side and end doors above referred
to, the temperature of the interior being somewhat
reduced in order not to effect the fusion of the sub-
stance very readily. Care must likewise be taken that
the bars of material are deposited within the furnace as
perfect as possible, in order that they may present in-
terstices for the flame and oxidizing current to pass
through, which will thereby effect a better roasting than
could be done, were the charge in small fragments. As
the blue metal is brittle, it is customary to employ a
kind of tool not very unlike a baker's peel, and which is
worked by four persons for introducing it. It is kept
at some distance from the bridge of the fire, as near this
it would meet little of the flame ; for this reason, about
two and a half to three, or even four feet are reserved
between the matter operated upon and the fire bridge.
The heat applied in this case is during the first part of
the operation is very moderate, but in proportion as the
sulphur is eliminated, and the oxidation of the metals
proceeds, it is increased, till in the end, it is raised suf-
COPPER SMELTING. 319
ficiently to bring the charge into a fluid state. By this
routine, the iron, which alone had been oxidized during
the roasting, is combined with the silica, and forms a
fusible slag, which is removed after drawing off the matt
of white metal.
The results of the charge are proportionally expressed
in the annexed table:
"White metal for the eighth operation, . 0.588
Poor slag for the second operation, . . 0.103
Furnace waste for the fourth operation, . 0.008
Sulphurous acid, ..... 0.124
1.000
Eighth Operation. This seems to be only a repeti-
tion of the preceding treatment, and is conducted in
almost the same manner. It constitutes the last of the
series called the extra-process, and yields a substance
which, like that resulting from operation four, in the
ordinary mode, is ready for the calcination by which the
metal is obtained. The charge weighs about one ton
and a half, and the time of working extends over seven
or eight hours.
Two stages are observed in it : first, the roasting,
by which a still further quantity of sulphur is expelled,
and oxide of copper, with sesquioxide of iron, is pro-
duced ; and, secondly, the fusion of the mass, as before
detailed, by which any iron may be separated in the
scoria. A reduction of some of the oxide of copper
contained in the slag is likewise effected ; when it comes
in contact with the matt of rich white metal, it yields
320 COPPER SMELTING.
oxygen to the sulphur in combination, and gives rise to
the formation of sulphurous acid and the precipitation
of metallic copper.
White metal from the seventh division is usually em-
ployed alone, especially if a first quality of copper is to
be produced ; but when this is not the case, the matts
procured from the fifth and sixth fusion are mixed with
it in the ratio tabulated as under :
White metal of the seventh operation, . 0.712
" " " sixth " . 0.125
Red metal of the sixth operation, . . 0.034
Earthy matters from the sole, . . . 0.041
" " " brjck and clay, . . O.OOT
Oxygen from the atmosphere, . . . 0.081
1.000
After the calcination is carried on with a gradual in-
crease of temperature for about three hours and a half,
the roasting is considered to be thoroughly performed ;
the fire is then urged, and the matter melted, and by
this means a further quantity of sulphurous acid is libe-
rated, in consequence of the action of the excess of
oxide of copper in the slag upon the matt of sulphide
of copper, by which the sulphur is oxidized, and a pro-
portionate weight of metal precipitated. This precipi-
tation of copper aids considerably in refining the matt
of any portions of arsenic, tin, &c., which may be con-
tained in it, and which it carries with it to the bottom.
During the three hours and a half fusion, these changes
are being instituted; and at the close, the charge is
COPPER SMELTING. 321
found separated into three distinct layers. Of these, the
upper one consists of scoria, mixed with oxide of copper ;
the middle of the pure matt or regulus ; and the under
one, of bottoms, or an alloy of copper and tin, with an
admixture of more or less matt. This is shown in the
annexed statement of results:
Regulus of metal seven for the ninth operation, 0.528
" " six " " " 0.112
Cupreous base from seven, . . . 0.088
" " " six, . . . 0.020
Slags to be used again in the sixth operation, 0.118
Furnace waste " " fourth " 0.004
Copper sweepings, " " sixth " 0.002
Sulphurous acid, ..... 0.128
1.000*
Ninth Operation. At this stage of our description,
we come back to the regular course of the smelting,
which we left in order to describe a series of processes
intended to bring into the final operations a class of
substances which are continually accumulating about a
smelting establishment. The last of these, which we
have called number eight, has produced a result which
may be mixed with the white metal from the fourth ope-
* I have quoted this entire description of the extra process from the
excellent article on Copper, in Muspratt's Chemistry, because it is the
fullest and most satisfactory account of the Welsh method of working
up the residues from the furnaces, and the various cupreous matters
which accumulate about a copper work. They are treated in this way,
because they would not be advantageously smelted in the regular course.
It is only employed when these matters have considerably accumulated.
COPPER SMELTING.
ration, or worked by itself for pig copper. Up to this
stage, the smelter has been availing himself of two sets
of reactions that between sulphur and oxygen, and
that between silica and oxide of iron. There has been
a continual process of oxidation resulting in the forma-
tion of sulphates of the two metals. As the iron salt is
more rapidly decomposed than that of copper, we have
a quantity of oxide of iron in the bath of molten mat-
ter that fills the furnace. This oxide, having a strong
affinity for silica at a high temperature, combines with
that substance to form a fusible slag. The sulphate
and oxide of copper reacting on the undecomposed sul-
phuret, produce sulphurous acid, which burns off, and
sulphuret of copper, with a minimum degree of sulphu-
ration, called by the smelters white metal, so that at
this stage we may consider a large portion of the sul-
phur, and nearly all the iron, finally separated. It
remains now to get rid of the remaining sulphur.
1 When no iron whatever is present, a simple roasting
and smelting, under proper management, will dissipate
the remaining sulphur. If, however, some iron remain,
it will be necessary to add some silicious matter, in order
to combine with the oxide of that metal, and thoroughly
to purify the copper. As it is rarely the case that all
the iron is separated in the fourth operation, it is cus-
tomary to add to this charge some rich quartzose ores.
Hence it will be seen that there are two objects to be
accomplished in this process one to roast the sulphur
off by the direct action of the atmosphere, aided by the
double decomposition going on between the sulphuret
and oxide of copper ; the other to get rid of iron by
COPPER SMELTING. 323
oxidating it and then combining it with silica. To ac-
complish these ends, the smelter divides this operation
into four distinct stages. In the first, he roasts the
material, by heating it, with free access of air ; in the
second and third, he manages the mutual decomposition
of the oxide and sulphuret of copper ; in the fourth, he
produces metallic copper, effects the union of the oxide
of iron with silica, and withdraws the slag.
The furnace in which this operation is performed,
resembles the other smelting furnaces, having a side
door, an end door, and a tap hole opposite the former.
The charge is from three to three and a half tons of
white metal and regulus, which are introduced in large
masses, and piled up on the sole of the furnace. The
openings are now closed and luted, and the heat is
raised. The combustible gases, as they sweep over the
mass of metal, gradually deprive it of much of its sul-
phur. If the furnace be watched at this time, little
drops will appear to sweat out of the red hot pigs, and
trickle down to the sole of the furnace. In this slow,
piecemeal fusion, abundant opportunity is afforded for
the oxidating action of the atmosphere. This first
stage of the process lasts about four hours, and is com-
pleted when the whole charge has become liquid.
The second stage now begins. A seething, or boiling
in fine bubbles, is now apparent throughout the entire
bulk of the charge. Every now and then a brilliant
spot is seen upon one of these little bubbles, and indi-
cates the conversion of a portion of it into metallic
copper. The reaction between the oxide and the sul-
phuret of copper is now going on.
This is completed in the third stage, which the work-
324 COPPER SMELTING.
man inaugurates by throwing open the doors, and admit-
ting atmospheric air, taking care to keep the fire in
such a condition that a partial closure of the openings
will at any time raise the contents of the furnace to
the necessary temperature. The first effect of the cold
air is the formation of a consolidated film over the whole
bath. Beneath this the action goes on violently, the
confined gases causing rents in this surface layer, and
throwing up new fluid from below. Presently, the
cooled layer becomes so thick and tenacious that the
gases cannot escape freely, but cause a great swelling
of the mass, together with an agitation that effects the
most thorough intermingling of the liquid contents.
This evolution of sulphurous acid goes on for ten or
twelve hours, at the end of which time the mass has
cooled, stiffened, and become extremely porous on ac-
count of the inability of the gas to escape. The fire is
now increased, the door closed, and the furnace brought
to a bright red heat. The mass again becomes liquid,
the gases are expelled, and the bath begins to boil with
larger bubbles, so lustrous that it is scarcely possible
to look at them. Six hours are usually taken up in this
fusion, and at the end of that time, the sulphur is nearly
all gone
All this time, the siliceous matters have been diffused
throughout the mass without combining with the ox-
ides, because the heat has been insufficient. In the
fourth and last stage, however, the heat is raised to the
highest point, and kept there till the process is ended.
The silicate of iron now forms a fusible slag, which,
being lighter than the copper, rises to the surface, and
floats over the metallic bath. It is raked off at the end
COPPER SMELTING. 325
door, and the taphole being opened, the copper flows
out into moulds. It is full of hubbies, brittle, with a
coarse, granular fracture, the freshly broken surface be-
ing of a deep red color and full of cavities.
It is sometimes called blistered copper, from its blebby
surface, and sometimes pig copper, from the forms in
which it is moulded. The slag which is raked off from
it, contains a large proportion of oxide of copper, and
not a little of the same in a metallic state. The oxide
is both in the form of a silicate and mechanically com-
bined with the mass. This alone is worked down in the
fourth operation.
In many furnaces, this process is divided in two. The
white metal, of the fourth operation, is oftener sixty
than seventy-three per cent., and its roasting in the
furnace would take up too much time, and be imper-
fectly effected. It has been found advantageous, there-
fore, to tap out this substance at about the commence-
ment of the third stage described above. As it flows
from the furnace in a thin stream, it is, of course, freely
exposed to the action of the air, and is very effectually
roasted. Lying in its sand moulds, it speedily chills
upon the surface ; but in the interior of the pigs, the
agitation of the liquid still goes on, giving rise to very
interesting volcanic phenomena. Numerous small open-
in^s are made in the film, and the boiling matter from
within is thrown out. It falls around the edges, making
little irregular cones, which rapidly increase in height,
till they resemble so many chimneys covering the pigs
of regulus. Molten matters are shot out by the intes-
tine commotion, far above their summits, and little
28
32fi COPPER SMELTING.
streams of lava trickle down their sides. The geologist
might gather some hints as to the action of volcanoes,
by studying the phenomena of these little elevations.
The regulus thus obtained, is often immediately charged
back into the same furnace from which it was tapped out.
The copper obtained by this operation, is, as we have
said, coarse and brittle, and unfit for the use of the
mechanic. It still contains sulphur and other matters,
which impair its tenacity. These are expelled in the
final process, which we are now about to describe.
Tenth Operation. This process is called refining or
toughening, and brings the copper to a marketable
condition. It is performed in a furnace resembling the
smelting furnace, except that the grate is larger, and the
arch is higher. The former modification is necessary,
because a greater heat is required than in the preceding
operations, and the latter, in order to avoid risk of oxi-
dation, which would take place rapidly under a low
arch. If this accident were to happen, the refiner
would witness what is called the rising of the copper.
The film of oxide on the surface would first consolidate,
then crack, and the liquid metal below would boil over
the crust. Copper, in this condition, would be unfit to
work, because it would not laminate. It requires a spe-
cial treatment.
The pigs of copper, produced in the last operation,
are charged into this furnace by means of a peel. These
are carefully arranged so as to present a large surface
to the action of the fire, and to allow the draught to pass
through them. The amount -of the charge varies from
three to six tons, and in some places, it is said that ten
tons have been worked. The heat is now kept up for
COPPER SMELTING. 327
about eighteen hours, during which time the copper is
calcining, the metal having melted in the first six hours.
The foreign metals and a good deal of the copper itself,
are oxidated and combine with the silica, which is always
present, in the shape of sand adhering to the pigs, and
furnace waste. The oxide of copper assists the scori-
fication of the other metals, which separate and rise to
the surface with the slag. The heat is now increased
awhile to ensure a proper fusion of the scoria, which
is then raked off. This scoria is heavy and compact,
of a dark or ruby red tint, due to the suboxide of copper,
and filled with filaments and beads of metallic copper.
At this stage the metal is ready for refining. It
is now dry, as the workmen term it, and contains a
quantity of oxide of copper diffused through it. Its color
is a deep red approaching to purple, its texture coarse,
open and crystalline, and its tenacity very slight. At
this time the refiner commences taking his tests or assays.
He has a long handled ladle with a small bowl, which
he dips into the melted metal. He then withdraws it,
suffers it to harden upon the surface and plunges it
into water to cool it. He cuts it partly through with a
chisel, and then he breaks it, forming his opinion of the
state of the copper by its color, its texture and its lustre.
If the metal were left uncovered at this high temper-
ature, it would speedily absorb still more oxygen than is
already combined with it. To prevent this, the refiner
covers the surface with charcoal, which as it burns off
absorbs the combined oxygen from the metallic bath.
This action however, is .confined to the surface of the
metal, as is that of the billets of green wood which are
now thrown on. To reach the centre of the charge,
328 COPPER SMELTING.
s tout poles of green wood are thrust below the surface of
the metallic bath, where they burn at the expense of its
oxygen. The ebullition produced by the escape of the
gases, causes a thorough intermingling of the constitu-
ents of the bath, and brings every particle of it in
contact with the deoxidizing agents. This poling, as it
is called, continues for twenty minutes or half an hour.
The refiner takes repeated tests during this process. If
the broken surface is dull and of a purplish or brick red,
he knows that there is still some oxide of copper mixed
with the pure metal. When the refining is complete,
the broken surface of the assay has a fine light red color,
and a soft satiny lustre ; as soon as this point is attained,
the refiner orders the poles to be withdrawn. Should
it be allowed to remain only a few minutes longer, an
unfavorable change takes place. The copper absorbs
carbon, and becomes even more brittle than before it
was refined at all. The assay reveals this condition of
the bath. Its color is a brilliant yellowish red, its frac-
ture fibrous and striated, and its grain coarse. When
this happens, the charcoal is pushed back and the doors
of the furnace are thrown open to admit the air, which
burns off the excess of carbon and restores the copper
to its maleable condition. On the other hand, if the
charcoal be not kept over the face of the bath, it absorbs
oxygen from the air and returns to its dry state. The
remedy for this is a fresh application of the green wood.
In the former case, the workmen say that the copper
has gone too far or that it is over pitch, in the latter it
has gone back or is under pitch.
It often happens that a difficulty occurs in separating
the foreign metals from the copper. This is overcome
COPPER SMELTING. 329
by the use of lead, which is an admirable scorifier and
forms fusible compounds with the different metallic
oxides, which rise to the surface and are raked off with
the slag. To accomplish this, it is necessary to rabble
the bath completely, so as to bring all the lead under the
influence of the oxygen, that it may all be found in the
slag. If any be allowed to remain in its metallic state,
it has a very bad effect upon the subsequent rolling of
the copper, in causing the scale to adhere to the surface
and preventing the proper cleansing of the sheets.
The refining being completed, the men dip the copper
out of a depression in the sole of the furnace just behind
the end door. For this purpose they use iron ladles
lined with clay. The metal is usually cast in ingots, in
moulds made of copper. As soon as these ingots have
consolidated, they are thrown into water. This gives
them a slight film of sub-oxide which adds to the beauty
of their appearance. If allowed to remain too long
exposed to the air, before being plunged into water,
they are coated with a scale of the black oxide which
makes them rough and unsightly. When required for the
rolling mill, the molten metal is cast into plates or bars.
Muspratt gives the following tables as representing
the charge and its results.
Charge.
Coarse Copper, 0.954
Earthy Matters, Sand, - - - 0.013
" Brick and Clay, - - 0.021
Oxygen of the air, -. -'./. ' -. - 0.012
1.000
28*
odO COPPER SMELTING.
Results.
Saleable Copper, - - - 0.908
Slag for Operation, four, - 0.055
Furnace "Waste, "... 0.022
Copper Sweepings, "... 0.002
Sulphurous Acid. - - - - 0.013
1.000
In the foregoing account of the processes adopted at
Swansea, I have chiefly followed Muspratt, who has
given us the most recent and one of the fullest and
most satisfactory descriptions of this elaborate system of
smelting. It must not be supposed, however, that the
routine there described, is servilely followed in all the
establishments for copper smelting on the Welsh plan,
much depends upon the kind of ore which is to be heated,
much also upon the nature of the fuel. The extra pro-
cess, intervening between the fourth and ninth opera-
tions, is often omitted, the substances to which it is
chiefly devoted, being smelted in small quantities at the
suitable stages of the regular process. At many works,
the product of the fourth operation, or the first smelting
after the calcination of the metal from the ore-furnace,
has not reached the stage of white metal. In that case
it undergoes a calcination to bring it up sufficiently for
smelting so as to obtain regulus or black copper. In
this country, where the ores smelted by this method
under consideration, are richer, and rarely contain either
arsenic, antimony or tin, the preliminary calcination is
commonly omitted. The ores are thrown raw into the
furnace, and calcination is performed upon the coarse
COPPER SMELTING. 331
metal obtained from them. This is then run down into
white metal and the rest of the plan, with the exception
of the extra process, goes on as we have described.
Under some circumstances, the calcination of the coarse
metal is omitted. Then, this product is introduced into
a smelting furnace and subjected to roasting and fusion
which produces Hue metal. This, in its turn, is roasted
and smelted in a similar manner, to produce white metal.
There are still further modifications sometimes adopted,
the whole depending upon the nature of the materials
submitted to the smelter. The skill of the master work-
man is shown in adapting these processes to the requi-
sitions of his particular work.
There is often a notable proportion of silver contained
in the copper ores worked at Swansea. This is some-
times entirely neglected. There are works however,
erected for the separation of the more precious metal.
In these, various plans are pursued, which being foreign
to our present subject, we shall not stop to describe.
We will only state that in some establishments the pro-
cess of liquation is adopted; in others amalgamation is
used ; while in others again, the metal is roasted with
common salt to form a soluble double chloride of silver
and sodium, from which the silver is precipitated by
means of metallic copper.
NAPIER'S PROCESS.
The plan of copper smelting, patented by Napier, is
said materially to shorten the operation and greatly to
diminish its expense.
When Cornish ores are worked in this method, they
332 COPPER SMELTING.
are first thoroughly calcined in an ordinary furnace and
then mixed with rich Cobre ores, or other sulphurets
rich in copper, in such proportions that the iron and silica
may combine, and the matt obtained may contain from
30 to 50 per cent, of copper. This mixture is fused
and skimmed in precisely the same manner as the cal-
cined ore in the second operation of the regular process.
As soon as the face of the metal is cleaned, a quantity
of soda-ash or salt cake is introduced, and well mixed
with the mass. The alkaline sulphuret, thus formed,
dissolves whatever antimony, tin or arsenic may be
mingled with the mass, forming with them soluble double
sulphurets. When salt cake is used, about 8 per cent,
of charcoal is mixed with it, to reduce the sulphate of
soda to a sulphide of sodium. As soon as the decompo-
sition is complete, which is usually but a short time, the
furnace is tapped and the matt cast into rectangular
blocks. These are thrown as soon as they have solidi-
fied, into tanks filled with water in which they crumble
to a fine powder. The water is now siphoned off and
the sediments washed to disolve out the double sulphu-
rets of antimony, tin and arsenic.
The residue is calcined to complete oxidation, an
operation which is generally completed in 24 or 30 hours.
The roasted metal is now mixed with coal or charcoal
and an additional quantity of ore, rich in silica, but free
from sulphur or arsenic, and smelted in the ordinary
way. Reduction takes place and a slag is produced
which contains but little copper.
When carbonates of copper or tile ore, containing a
small percentage of earthy bases and a large amount of
COPPER SMELTING. 333
silica, are treated in this way, the iron scales from the roll-
ing mill and forging hammer are added, in order to form
a fusible slag. Rich iron scoria or carbonate of iron
may be used instead of the scales, but all sesquioxides
must be avoided, as they part with a portion of their
oxygen which combines with the copper and deteriorates
the product. If the slags are too stiff, they may be
lightened by the addition of salt or quick lime.
BRANKART'S PROCESS.
Like Napier's, this plan combines the humid with the
dry treatment. The rich ores from South America and
Cuba are treated by this method, at the Red Jacket
Copper Works in Neath, Glamorganshire. The ore is
reduced to a fine powder, and then roasted in a rever-
beratory furnace till the sulphurets are oxidized to sul-
phates. The calcined ore is then thrown into large vats
or tanks filled with water. In these the sulphates of
copper and iron are dissolved, the supernatant liquor
siphoned off into other vats containing scraps of old iron
which precipitate metallic copper. When all the copper
is thrown down, the iron salt may be crystallized out of
the mother liquor after suitable concentration. The in-
soluble residue is dried, mixed with a fresh proportion of
ore and again submitted to the process of calcination.
The copper which has been thrown down by the iron, is
roasted, fused and cast into ingots.
RIVOT AND PHILLIP'S PROCESS.
The ore is roasted dead, that is to the expulsion of
sulphuric as well as sulphurous acid, and the consequent
334 COPPER SMELTING.
conversion of all the sulphurets into oxides. When this
has taken place, bars of iron are introduced, at this high
temperature, these rapidly oxidate at the expense of the
cupreous oxide, and form with the silica a fusible slag
which is raked off, leaving a bath of metallic copper.
The objections to this process are that it uses a great
deal of metallic iron, and that it does not accomplish the
purification of the copper if tin, arsenic, or antimony are
found in the ores.
DAVIES' PROCESS.
This is applicable only to oxides and carbonates of
copper which contain no other metals than iron and
manganese. These are mixed in such proportions that
the silica of the ores may be to these oxides as five to
seven. If silica be in excess, oxide of manganese is
added, and if this oxide or that of iron be superabundant
more silica is introduced. The whole being well mixed
with coal, is then smelted to produce the metal.
BIRKMYRE'S PROCESS.
Copper pyrites is the ore treated according to this
method. After being finely powdered and mixed with
nitrate of soda, it is placed in trays and introduced into
kilns resembling those commonly employed for roasting
pyrites. While exposed to the heat, it is repeatedly
stirred with a rake in order to bring every particle of it
within the influence of the air that passes through the
furnace. The nitrate of soda assists the atmosphere to
oxidate the sulphur and its metallic bases, and the re-
sult of the operation when effectually performed is a
COPPER SMELTING. 335
mixture of the sulphates of iron, copper and soda, with
undecomposed silicates. The soluble salts are leached
out and the copper precipitated, as in Napier's process,
bj means of metallic iron.
DE SUSSEX'S PROCESS.
The patentee directs that the ores be so mixed as to
contain about sixty per cent, of silica. Should there be
more than this, fluor spar, lime or any other substance
which will form fusible compounds with it, is added.
Twenty-five pounds of finely burned charcoal, or of
stone coal free fronr-sulphur, for every five hundred-
weight of mixed ore are then incorporated with the
charge, and the whole introduced into a reverberatory
furnace. In three or four hours, most of the sulphur
will be expelled, but to effect its entire separation, the
temperature is to be lowered, and about five per cent, of
alumina, magnesia or magnesian limestone, or if these
cannot be had, of nitrate of potassa, soda, or lime to be
intimately mixed with the charge. The heat is then in-
creased to decompose sulphate of copper. The roasted
ore, mixed with an equal weight of anthracite coal, and
four parts of silicate of potash or soda for every ten parts
of silica in the substance, is then melted to obtain the
metal. The patentee suggests, if the roasting be insuffi-
cient to expel all the sulphuric acid, the remaining sul-
phate of copper be decomposed by digestion in a tank of
ammoniacal water, which must, of course, contain exactly
enough ammonia to decompose the unknown quantity of
copper salt.
The whole plan is curiously unpractical.
adb COPPER SMELTING.
LOW'S PROCESS.
This is another method which could not be carried on
by ordinary workmen with any reasonable prospect of
success. The patentee proposes to employ a mixture of
peroxide of manganese, 42 parts ; plumbago, 8 parts ;
nitrate of potassa, soda, or lime, 2 parts ; wood charcoal,
or anthracite, 14 parts. While the fusion for matt is
going on, 25 pounds of this mixture are added and rab-
bled thoroughly with the molten mass. The slag which
rises is skimmed off, and a fresh quantity of the flux
added, and the same operation repeated till the workman
considers that the copper has advanced sufficiently to be
tapped out for reduction in the smelting furnace.
OTHER PATENTED PROCESSES.
Parkes recommends that the mineral be roasted till a
matt called close regule is formed, when iron is added in
the proportion of a hundred weight to each two and a half
tons of the above compound. The heat is then urged so
as to keep the whole mass in perfect fusion for some
time, and the metal is finally tapped out as pimpled cop-
per. He also suggests the use of the refining process
previous to poling, but it is objectionable on account of
the probable bad effects of its oxide on the furnace bot-
toms.
Trueman and Cameron roast their sulphates, boil the
calcined ore in a solution of caustic potash for six hours
to separate the tin, arsenic and antimony. The residual
ore is again roasted to produce an oxide which is mixed
with a fresh portion of crude ore in the proper propor-
tion to convert all its sulphur into sulphurous acid. The
COPPER SMELTING. 337
silica should be so proportioned to the iron as to form
with the oxide of that metal a fusible slag, and either sand
or cobbing must be added if silica be deficient. The mix-
ture is fused in quantities of two and a half tons for every
charge. Five hours after charging, the mass is well rab-
bled, then allowed to rest, the slags being skimmed as they
rise to the surface. Another charge is then introduced
and treated in the same manner, the furnace being tapped
only at every second charge. This yields a rich sulphu-
ret of copper free from iron, which furnishes copper of
good quality when calcined and fused in the reducing
furnace.
A second patent, granted to Trueman in 1852, pro-
poses to treat the ores with an acid, and to precipitate
copper from this solution with lime or its salts.
FRENCH METHOD OF COPPER SMELTING.
We have spoken, in a previous part of this work, of
the ores of Chessy, near Lyons. They are red and
blue, the former an oxide, the latter a carbonate of cop-
per, mixed with a greater or less proportion of impuri-
ties. The red ores contain from 38 to 76, the blue from
20 to 26 per cent, of metallic copper. The impurities
consist of susquioxide of iron and compounds of silica
and alumina.
The furnace in which these ores are smelted is called
by the French fourneau a manche. Its base is made of
very solid masonry, strengthened by transverse bars of
iron. The cavity is lined with a coating of very refrac-
tory material, cemented to the masonry in the form of
an ellipse, and renewed every season. The two lateral
29
338 COPPER SMELTING.
faces are constructed of gneiss, and the front, called fier-
vende, of -rectangular iron plates, coated with fire-clay.
The cavity is a rectangular parallelepiped about six feet
long, five and a quarter broad, and three and a quarter
deep. The sole is formed of a fire-brick made from
Bourgogne clay and pulverized quartz. The tuyere has
an orifice three inches in diameter, its muzzle being
wrought and its bed cast iron. Opposite it is a platform
made of clay firmly beaten, in which there is dug a crucible
on a level with the sole of the furnace. It is coated with
a mixture of clay and finely powdered charcoal, and
from it passes an inclined canal leading to the receiver
in which the fluid collects.
The ore is mixed so that its average content of copper
shall be about 27 per cent. To this is added 5 per cent,
of lime and some scoria. Every hour, 200 pounds of
this mixture mingled with 150 pounds of coke are thrown
into the furnace. As the fusion goes on, the melted
metal and slag flow out together into the crucible, when
the slag is skimmed off. As soon as the metal fills the
basin, it is run into the receptacle. A little water
sprinkled over the surface of the metal causes the forma-
tion of a skin or crust which is removed from the bath.
The continued repetition of this process converts the
entire bath into round cakes about an inch thick. The
metal is run off from the crucible twice in twenty-four
hours, and the entire daily product is about fourteen
hundred weight,
The slags differ in their composition according to their
color or to the source from which they are taken. A
little scoria unavoidably runs over into the receiver, and
COPPER SMELTING. 339
this differs from that which is skimmed from the cruci-
ble in containing no lime. It is essentially a silicate of
iron mixed with a little sulphur and other impurities,
containing about 4.5 per cent, of copper, together with
a little metallic iron. It is formed by the action of the
air upon the metals of the bath, and the subsequent re-
action of the oxides upon the silicious matter of which
the receiver is composed. This corrosion renders ne-
cessary the repeated renewal of the walls of the recepta-
cle, which must be repaired weekly. The slags which
are skimmed from the crucible are of three colors, blue,
black and red. Of these the blue contain the least ox-
ide of copper, and are formed when lime is present in
due proportion. The black slags contain more copper,
and are produced when lime is deficient, or when black
slag from a previous operation has been added in too
great quantity. Red slags are silicates of iron and cop-
per, and are formed when the silica is not properly pro-
portioned to the earthy bases, or when the heat is too
high, melting the slags before the carbon has time to
reduce the suboxide to metallic copper. In the first in-
stance, these scoria are converted into the black variety
by the addition of lime ; in the second it is only neces-
sary to reduce the temperature of the furnace.
The black copper obtained from this furnace varies in
composition. That from which the black slags have been
taken contains from 7 to 8 per cent, of iron. Like all
copper obtained from blast furnaces, in every instance
it is more or less contaminated with iron. The different
layers or discs, which have been removed from the same
bath vary in their composition, the lower strata being
340 COPPER SMELTING.
richer in copper on account of the greater specific gravity
of that metal.
The average composition of this black copper, as
determined by the means of several analysis by M.
Margerin, is stated in the following table :
f. wsrfit* 9!?J fcrt ,-ite
Copper, . .,*..
T rr
Iron, .... . |af v . . ..
T> 'J / T
Protoxide of Iron, .. n - . J . .
Silica, . ""I. 1 '' 1 j. '" . . . . .
Sulphur, . ^1 ?OV ' '
T
SS ' - ' i 'ft
100.00
This copper is refined in a spleiss-ofen, which, together
with the process, will be presently described.
SMELTING OF THE MANSFELD COPPER SCHISTS.
The copper schists of Mansfeld are, as we have
already said, poor in copper, but their great abundance
enables the metallurgist to extract that metal from them
with profit to himself. The process adopted is very
ingenious, advantage being taken of the bituminous
matters diffused throughout the mass.
The first operation is the calcination of the ore in
mounds containing each about a hundred. The broken
shales are interstratified with wood, and the combustion
is carried on partly by this fuel and partly by the bitu-
men of the slate. These heaps continue burning fifteen or
twenty weeks, at the end of which time the carbonaceous
matters are consumed, much of the sulphur expelled as
COPPER SMELTING. 341
sulphurous acid and the metals generally oxidated. The
calcined ore is friable, yellowish-gray, and about one-
tenth lighter than it was before the operation. In the
Lower Harz, the heaps are so arranged as to collect and
preserve the sulphur.
The calcined ore is mixed with from six to twenty per
cent, of fluor spar, some slag (containing copper) ob-
tained from a previous operation, and some copper schist
containing carbonate of lime. An ordinary charge con-
tains twenty hundredweight of ferruginous, fourteen
of calcareous and six of argillaceous copper schist,
mixed with three of fluor spar and three of rich slag.
The time of working this is about fifteen hours, and
the product about one-tenth of its weight of copper
matt, containing from thirty to forty per cent, of me-
tallic copper.
The other metals present in the ores, nickel, cobalt
and silver, together with zinc and iron, are found in this
matt in the state of sulphides. The subsequent treat-
ment of this matt depends upon the quantity of copper
it contains. When rich, it is roasted five or six times
and then smelted into black copper. When it contains
no more than twenty or thirty per cent, of copper, the
cakes of matt, alternated with brushwood, are roasted
three successive times in kilns, the product being turned
over after each calcination. The charge in this instance
weighs three tons, and the operation occupies four
weeks. The next process consists in the fusion of this
roasted matt in a cupola, the result being a rich product
called spurstein, containing from fifty to sixty per cent,
of copper. This is mixed with material from the first
29*
342
COPPER SMELTING.
smelting, and roasted six times consecutively during a
period of seven or eight weeks. The fuel consists of
brushwood and charcoal, which are interstratified with
BLAST FCRNACB.
6 6. Exit openings.
ELEVATION.
BLAST FURNACE.
A. Shaft.
the matt, the air being admitted to the lower part of the
mass by channels opening inwardly at the bottom of the
kiln. The kiln is built of stone, and consists of six
COPPER SMELTING. 343
compartments, so arranged that the charge in one of
them shall not mix with that in the adjoining one. The
process is a continuous one, the roasted matt of the first
compartment being introduced into the second, with the
same arrangement of brushwood and charcoal, then into
the third, and so on till the process is fully completed
in the sixth. The gahrrost, as the Germans call the
resulting product, resembles in color red copper ore,
with an occasional bluish-gray tint. It is brittle and
contains some reduced copper as well as sulphate and
oxide of that metal. To separate the sulphate, it is
lixiviated in a descending series of vats, so arranged
Fig. 13.
BLAST FURNACE.
B B, basins, 6 tap-door, c c channel to conduct metals to furnace, 1 1 tuyeres.
that the solution drawn off from one shall pass through
the next below in regular succession, till it becomes so
concentrated that it can be crystallized with very little
344 COPPER SMELTING.
evaporation. Sometimes this process is carried on after
each roasting in the compartments of the kiln pro-
ducing the gahrrost. The calcined and lixiviated matt
is generally melted with one-fourth its weight of lixiviated
matt from the first fusion, and, when this is of good
quality, one-sixth to one-tenth its weight of rich copper
slags, with sufficient charcoal and coke. This mixture
is smelted in the cupola furnace in quantities of three
or four tons, the operation occupying twenty-four hours.
The results are hlack copper and slags of variable rich-
ness ; the metal, owing to its greater specific gravity,
sinking to the bottom of the crucible, and being removed
in cakes, as before described. The slag is subsequently
roasted with matt and smelted to extract its copper.
The black copper is by no means pure, since it contains
the various metals already mentioned as present in the
ore. Of these, silver being the most important, is sepa-
rated by a special process.
This is usually what is known by the name of liquation,
though sometimes the precious metal is separated from
the gahrrost by amalgamation. The process of liquation
depends upon the low fusion-point of an alloy of silver
with lead or zinc. Three parts of the black copper are
fused with ten or twelve parts of lead or an equivalent
proportion of litharge rich in silver. The alloy is run
into moulds, where it is rapidly cooled by water, and
lifted out in discs of an inch or less in thickness. These
are then placed on the hearth of a furnace of peculiar
construction, and heated gradually. The melting point
of the lead alloy being far below that of copper, the
silver-lead flows out and is collected. When no more
COPPEE SMELTING.
345
oozes from the cakes, these are transferred to another
furnace where they are subjected to a higher heat, by
which more silver is recovered and the cakes left in a
purer state. They still, however, contain a little silver
and some lead, but the latter metal is entirely removed
in the subsequent operation of refining.
The refining is carried on either in a spleiss-ofen
(split-hearth furnace) or in the arrangement figured
below. The spleiss-ofen is a furnace of peculiar con-
struction, consisting of a sole communicating by sepa-
rate channels with two basins into which the copper
flows. These, the split-hearths, are connected with one
another by a canal. The channels leading from the
Fig. 14.
Fig. 15.
REFINING FURNACE.
a Crucible, c Iron curb to prevent waste
of charcoal, d Charcoal for slag, t Tuyeres.
SUCTION OF REFINING FURNAGE.
Crucible, t Tuyeres.
main hearth are provided with fire bricks to contract
them till the discharge of metal is allowed. The main
hearth is elliptical in form, eight feet long by six and
a-half wide, and is made of a mixture of coal-dust and
clay well beaten into a clay bottom, resting upon a bed
346 COPPER SMELTING.
of brick-work, the whole being supported by a slag bot-
tom built on a foundation of gneiss. Two tuyeres,
through which the blast from the bellows is thrown,
complete the arrangement. The charge for this fur-
nace, amounting to sixty hundredweight, consisting of
black copper mixed with granular copper and copper of
cementation, is introduced through the working-door
and spread over the sole of the furnace. As soon as it
has melted, the bellows begin to play over the surface
of the bath. Soon a layer of cinders and scoria collects
upon the face of the metal. This is skimmed off. A
second and third layer follow, and each is skimmed off
as soon as it forms. When no more slag is formed, the
fire is increased and the liquid begins to boil, continuing
to do so for three-quarters of an hour or an hour, after
which it remains tranquil although the heat be kept up.
In about three-quarters of an hour after the boiling has
ceased, the refining is finished ; the furnace is then
tapped and the charge received in the basin. At this
time a reddish mist hovers over the surface. This is
composed of extremely small globules revolving with
great velocity upon their axes. They are composed of
a nucleus of pure metal covered with a layer of pro-
toxide. The Germans collect them and use them as
sand for letters. The copper is removed in disks by
sprinkling water upon the surface and lifting off the
cooled layer. It is known in commerce as rosette
copper.
The liquated copper is treated in a furnace of simple
construction. It consists of a hemispherical crucible,
sixteen inches in diameter, rendered fire-proof by a
COPPER SMELTING. 347
coating composed of two parts of powdered charcoal
and one of fire-clay, into the cavity of which open the
tuyeres. When it is used, the crucible is first filled
with lighted charcoal, then more fuel is introduced, and
with it pieces of black copper which are deposited oppo-
site the tuyere. The blast is gradually admitted, and
as soon as the metal of the first charge has been fused,
another supply of the black copper, mixed with sufficient
charcoal to effect the reduction, is put in. This process
of repeated charging is continued till the crucible is full.
The slag which is formed during this process flows out
through a channel provided for it into a receiver, where
most of the copper it contains settles to the bottom.
As soon as the crucible is full, the copper is tested by
introducing an iron proof-rod and withdrawing a scale
of metal, which is immediately immersed in cold water.
When the assay is brownish-red on the outside, copper-
red within, thin and brittle, the refining is considered
finished. The blast is then cut off, and the iron and
slag raked from the surface of the metal, which is re-
moved in the usual way with the aid of cold water, till
the whole charge is converted into rosettes.
The charge for an ordinary furnace of this kind is
two and a-quarter or two and a-half hundredweight,
though larger furnaces will work up seven hundred-
weight. In the first instance, the refining occupies
three-quarters of an hour, while in the second two hours
are required. The object of the process is to oxidate
the more readily scorified metals, lead, iron, nickel, &c.,
and to run them off in the slag. This is not fully
accomplished, as the refined copper always retains ap-
348 COPPER SMELTING.
preciable quantities of these impurities. The slags vary
in color at the different steps of the operation. At first
they are greenish, containing much oxide of iron but
little copper. Towards the close of the operation, how-
ever, they become heavier and assume a deep red color,
owing. to the presence of suboxide of copper. These
are of course worked over again in the process for
obtaining black copper.
These rosettes are never pure enough for making
rolled copper. They are accordingly submitted to an-
other operation, which consists in melting them under
cover of charcoal to absorb their excess of oxygen.
Tests are frequently taken and the process is continued
till the full malleability is obtained. When the action
of the charcoal has been so prolonged as to form a car-
buret, the bath is uncovered and the bellows compelled
to play over it, in order to burn off the excess of carbon
as carbonic acid.
Copper is sent to market in various forms, the most
common of which is the ingot. Bean and feathered
shot are obtained by pouring the refined metal into an
iron perforated ladle placed over water. If the water
be hot, the copper assumes the form of rounded grains
which are known as bean shot; if it be cold, the drop-
pings of metal jvill be flattened, irregular and branching,
and to these has been given the name of feathered shot.
Japanned copper is made by casting the refined in small
ingots, which are thrown, while quite hot, into cold water.
By this treatment, the metal acquires a fine red coating
of suboxide which gives it value in the eyes of the ori-
entals to whom it is exported from England.
CHAPTER VI.
ALLOTS OF COPPER.
THE alloys of copper are both numerous and valuable.
The great majority of all the alloys in common use con-
tain copper as a principal ingredient. In the following
description of these compounds, brevity is aimed at ;
those which possess merely scientific interest will be
only glanced at or entirely neglected.
With the metals of the alkalies and of the alkaline
earths, copper forms alloys not often met with. Potas-
sium and sodium have been thought to increase the
malleability of copper. Dumas describes an alloy of
this kind composed of copper 99.12, potassium 0.38,
calcium 0.33 and iron 0.17 in the hundred parts.
That copper combines with aluminium has long been
known, for alumina has been obtained from some varie-
ties of commercial copper. The recent researches of
Sainte-Claire Deville have given us a more definite
knowledge of these substances. Some of these alloys
are light, hard and white, others yellow. Very small
proportions diminish materially the malleability of alu-
minium, communicate to it a blueish tinge and render it
liable to blacken by exposure to the air. On the other
hand, small proportions of aluminium harden copper
without materially affecting its malleability, and give it
the color of different varieties of gold. By combining
30
850 ALLOYS OF COPPER.
100 parts of copper with 10 of aluminium, an alloy is
obtained, harder than that used for money, malleable,
resembling in color the pale gold of the jewelers and
taking a brilliant polish. The alloy of 100 parts of
copper with 5 of aluminium is softer, approaches more
nearly in tint to pure gold, and is also susceptible of a
high polish.
With manganese and cobalt, copper also forms alloys
under favorable circumstances. Iron is difficult to
alloy with it, and generally renders it brittle and coarse
in the grain. I have, however, made an alloy of copper
and iron which was quite malleable. Cast iron is ren-
dered brittle by copper. I recently received for analy-
sis a cast iron containing copper which was so brittle
that it was easily reduced to powder in a common iron
mortar. Binman recommends a mixture of 100 parts
of gray cast iron with 5 of copper as a suitable material
for anvils, on account of its hardness.
With arsenic, copper forms a white alloy, sometimes
used for thermometer and barometer scales, dials, &c.
It is composed of 9 parts of copper and 1 of arsenic.
To attain this proportion, however, it is necessary to
introduce 3J parts of the latter metal before fusion,
which operation is conducted under salt, in a closed cru-
cible.
The most important of all the alloys of copper are
those which it forms with zinc, tin, lead and nickel ; arid
these we now proceed to describe under their commercial
titles.
Brass. This is an alloy of considerable antiquity,
though not so old as bronze. The first writer who
ALLOYS OF COPPER. 351
speaks distinctly of it is Aristotle. In the time of Au-
gustus, cadmia is spoken of, and we are informed that
it was used in the manufacture of aurichalcum, as brass
was called.
Though all alloys of copper and zinc are known by the
generic name, brass, yet there are numerous varieties
which have received different names. Almost every
variety of tint between the red of copper and the white
of zinc, can be communicated to these alloys by the
modification of the properties of the two metals employ-
ed. Although the metals named are the only essential
constituents of brass, yet this alloy often contains others,
added for some real or fancied improvement in working,
or accidentally present from impurities in the constitu-
ents. Lead, tin and antimony are the most common of
these foreign bodies. Iron is sometimes present and is
always injurious. It does not combine chemically with
the alloy except in very minute proportions, but is found
disseminated through the mass in small magnetic parti-
cles. It makes the alloy hard and dull, diminishes its
tenacity and malleability, and renders it liable to tarnish
and rust when exposed to the air. The source of this con-
tamination may be either the calamine from which brass
is often made, or the old brass which is melted over.
Tin and lead are not so injurious. Their presence is
even considered beneficial in some particulars. They
usually come from old brass which has been tinned or
soldered, or from rosette copper, from which the lead,
employed to separate the silver by liquation, has not
been completely separated in the subsequent process of
refining. " This brass, although it is harder and more
352 ALLOYS or COPPEK.
brittle than the ordinary kind, is more easily worked
under the lathe, but that which is dry is generally pre-
ferred by the turner ; it may be welded together, and
the junction is not easily broken ; in addition, it can be
cut with a chisel, sawn, and penetrated with exactness."*
The following table expresses the composition of several
varieties of this kind of brass. No. 1 is a cast of brass
of uncertain origin ; 2 the plate brass of Jemappes ; 3
the sheet brass of Stolberg, near Aix-la-Chapelle ; 4
cast brass of Stolberg :
1 2 3 4
Copper, 61.6 64.6 64.8 65.8
Zinc 35.3 33.7 32.8 31.8
Lead, 2.9 1.4 2.0 2.2
Tin, 0.2 0.2 0.4 0.2
100.0 100.0 100.0 100.0
The proportions generally thought to produce the
finest brass, are 63 of copper to 32 of zinc. These are,
however, continually varied in practice as may be seen
by the foregoing analyses. Sometimes the variation is
the result of accident, though it is frequently made in-
tentionally, with a view of providing for some particular
contingency. " Thus, when a rich alloy of considerable
tenacity is required, the zinc is reduced to 25 per cent.,
while with one of little resisting power, 50 per cent, of
zinc may be used, and should a hard and very brittle
compound be desired, the zinc is raised to 60 per cent."f
Gilding metal is more variable in its composition,
though resembling in the main the variety just described.
* Muspratt's Chemistry, i. 535, article COPPER. f Ibid.
ALLOYS OF COPPER.
It should be very close-grained and compact, so that
none of the gold will be obscured by the shining through
of a duller metal. The following table sufficiently ex-
presses the varying composition of this alloy :
Copper, .
Zinc, . .
Tin, . .
Lead, . .
1
2
3
4
5
63. TO
64.45
78.48
78.84
82.3
33.55
32.44
17.22
17.31
17.5
2.50
0.25
2.87
0.96
0.2
0.25
2.86
1.43
2.87
0.0
100.00 100.00 100.00 100.00 1QP.O
The densities of Nos. \ and 2 are 8.395 and 8.542 re-
spectively, and they are considered by D'Arcet to be
the best adapted to the purposes of the jeweler. The
quantity of copper is often increased to 90 or 95 per
cent., when the composition is analogous to chrysocolla,
and is known as gilding metal.* The other brasses in
the table resemble Bath metal, pinchbeck, similor and
Mannheim gold.
Although lead and tin do not deteriorate the varieties
of brass we have just been considering, they would be
seriously detrimental to those which are to be hammer-
ed, rolled or drawn, did they occur in large quantities.
The following table expresses the results of several analy-
ses of brass wire. No. 1 is English brass wire ; 2 Augs-
burg wire; 3 wire made at Neustadt-Ebenwald, near
Berlin :
* According to analysis, the composition of cbrysocolla is :
Copper, . . . 90.0
Zinc, .... 7.9
Lead, .... 1.6
30*
354 ALLOYS OF COPPER.
12345
Copper, .... 70.29 71.89 70.16 66.2 67.0
Zinc, 29.26 27.63 27.45 33.0 32.0
Lead, 0.28 0.20 0.5
Tin, 0.17 0.85 0.79 .08
Antimony, ... .05
100.00 100.37 98.60 100.0 100.0
Malleable brass or yellow metal, intended to work well
under the roller or hammer, should approach as nearly
as possible to the constitution of 70 of copper to 30 of
zinc. The sheet brass of Romilly contains, by analysis,
70.1 of copper and 29.9 of zinc.
The brass used for machinery and locomotives in Eng-
land is composed according to the following table :
Copper, . . .74.5
Zinc, .... 25.0
Lead, ... 0.5
100.0
Its fracture is of a fine yellow color, but its mallea-
bility is inferred to those varieties in which the propor-
tion of zinc is smaller.
The usual manner of expressing the composition of an
alloy among brass founders, is to name simply the zinc,
the quantity of copper being always taken as a pound.
The following descriptions of the composition of different
varieties of brass will be given in this method rather
than the centesimal.
TRUE BRASS is formed of two parts of copper and one
of zinc, but in this as in all the other alloys of copper
ALLOYS OF COPPER. 355
and zinc, more of the inferior metal, owing to its greater
volatility, must be added in order to obtain this propor-
tion. Muntzs metal is made with 10 ounces of zinc
to the pound of copper, his sheathing with from 9 to 16
ounces, according to Muspratt. Bristol brass, and those
varieties generally which bear soldering, contain less
zinc. The formula for Bristol brass, given by Muspratt,
is 6 ounces of zinc to the pound of copper.
When cTirysocolla is formed, or when it is desired to
give the brass the property of casting well, from an
eighth to a half ounce of zinc is alloyed with each
pound of copper. The two metals, however, are not
alloyed directly, but the result is obtained by fusing 4
ounces or less of brass with a pound of copper. Gilding
metal is made in the same manner, so as to obtain the
proportion of an ounce or an ounce and a quarter to the
pound.
Princes metal, or Prince Rupert's metal, contains
about equal parts of the two metals. Mannheim gold
contains 3 or 4 ounces of zinc to the pound. It is said
to be made by melting separately 3 parts of copper
and 1 of zinc, and then suddenly incorporating them
by stirring. Red brass, or tombaJc, as it is called by
some, has a great preponderance of copper, containing
from 5 ounces of zinc down to J ounce of zinc to the
pound. At Hegermuhl, 11 parts of copper are alloyed
with 2 of zinc to make a red brass, which is afterwards
rolled into sheets. At Niirnberg, Dutch foil is made
from a similar alloy. Pinchbeck is made of 2 parts of
copper and 1 of yellow brass. Similor is made of 28
parts of copper, 12 of yellow brass, and 3 of tin. Bath
metal consists of 32 parts of copper and 9 of zinc.
356 ALLOYS OF COPPER.
Brass solder, or hard solder, is made by melting
together 2 parts of brass with 1 of zinc, and a little tin.
When the solder is required to be very strong, as for
brass tubes that are to be drawn, one-third less zinc is
used. The platin of the Birmingham button-maker is
made of 8 parts of brass and 5 of zinc. Cast white
metal buttons are made of 32 parts of brass, 4 of zinc,
and 2 of tin. Mosaic gold, according to the specifica-
tions of Parker & Hamilton's patent, consists of 100
parts of copper to 52 or 55 of zinc.
Brass may be made either by the direct combination
of the pure metal, or by the action of copper on a mix-
ture of zinc ore and charcoal at a sufficiently high tem-
perature. The latter method is by far the most ancient,
and by it brass was made long before metallic zinc was
known. When an ore of zinc is employed, it should be
free from sulphur and from silicate of zinc, and should also
be well calcined in order to facilitate the reduction of
the metal. To accomplish this, the calamine is roasted
in heaps, alternate layers of ore and charcoal being
erected into a mound, the base of which is composed of
billets of wood. It is then ground, sifted and mixed
with charcoal. The pots which are to be used in the
manufacture are first heated in a furnace, then the mix-
ture of calamine and charcoal is introduced into them,
and the necessary quantity of rosette or grain copper
forced into the mixture by a few blows of a mallet or
hammer. The surface is then covered with a layer
of the mixture, the pots returned to the kiln and sur-
rounded with fuel. The furnace is now closed, and the
heat kept up for six or seven hours, at the end of which
ALLOYS OF COPPER. 357
time, the contents of the pots are at a white heat. At
the close of this period the heat is pushed, till the fumes
of volatilizing zinc, indicating the reduction and fusion of
this metal, make their appearance. The heat is now
diminished to prevent the too rapid melting of the copper,
and to ensure the thorough mixture of the two metals.
For three or four hours the heat is nicely regulated,
at the end of which time, the combination is complete.
The first result of this fusion is arcot, a brass contain-
ing less than the standard proportion of zinc. This is
again fused with an additional quantity of charcoal
mixture to make the ordinary commercial brass.
The other method possesses advantages over the one
just described. By fusing the metals, not only are fuel
and labor, but a larger product is obtained in a given
time. This method of direct fusion is, however, attended
with difficulties. Not the least of these is the great
affinity of zinc for oxygen, in consequence of which it
not only loses its power of combining with copper, but
is rapidly volatilized, causing considerable loss. For this
reason, the operator is compelled to employ much larger
proportions of zinc than he wishes to have in his fin-
ished alloy. This loss may be diminished by covering
the surface of the metallic bath with suitable fluxes, and
thus preventing this unfavorable action of the atmos-
phere. Lord Rosse is said to have made the greatest
improvements in this direction. By deepening the kiln
and keeping the surface of the bath constantly covered
with a layer of powdered charcoal two inches thick, it
is pretended the loss of zinc is not more than 0.56 per
cent, or T j<j- of the entire amount of that metal.
358 ALLOTS OF COPPER.
How great this loss usually is may be learned from
Holzapffel's careful experiments. His loss was about
the thirtieth of the whole alloy. He fused twenty-four
pounds of copper, and then gradually introduced twelve
pounds of zinc. The surface of the metal was then
covered with glass and left until the contents of the pot
were in perfect fusion. The alloy thus obtained, instead
of 33^ of zinc, contained only 31 . On remelting the
alloy, it continued to lose zinc, till after the sixth opera-
tion that metal was reduced to 4f ounces to the pound.
The specific gravity of brass is greater than the mean
density of its constituents. Sheet brass varies from
8.52 to- 8.62; brass wire from 8.49 to 8.73.
GERMAN SILVER. This alloy has been known by
various names, as British plate, Argentan, Cuivre blanc,
Maillechort, Neusilber, Weisskupfer, &c. It is an alloy
of copper with nickel and other metals. The Chinese
have long used it under the name of pakfong, or white
metal, but in Europe it has only been known for the
last hundred years. It was first made in Germany, by
smelting ore found at Hilburghausen, near Sahl, in
Henneberg. Referstein's analysis of the original com-
pound gave the following results :
Copper, 40.4
Nickel, 31.6
Zinc, . . . 25.4
Tin, 2.6
100.0
The Chinese pakfong always contains iron, which
ALLOYS OF COPPER. 359
gives a brighter color to the alloy and renders it more
compact, though it also makes it hard and brittle.
Nickel being rather a raw metal, attempts have been
made to diminish it by substituting zinc for it. These
are successful only when the zinc is limited to a cer-
tain point, beyond which, if any be added, the compound
though looking well at first, assumes the hue of pale
brass. The following table, copied from Muspratt, ex-
presses the composition of the varieties of this alloy:
1 23 4 56 7 8 9 10 11
Copper, . 43.8 40.4 53.4 50.0 6.5.4 60.0 67.0 59.2 550 51.6 45.7
Nickel,.. 15.6 31.6 17.5 18.7 16.S 20.0 20.0 14.8 20.6 25.8 34.3
Zinc, 40.6 25.4 29.1 31.3 13.4 20.0 20.0 26.0 24.4 22.6 20.0
Iron, 26 3.4
Lead, 3.0
100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
Numbers 1 and 2 are analyses of Chinese pakfong,
the latter being very superior in color and taking a high
polish. Nos. 3 and 4 are alloys, prepared by Frick,
resembling a silver about 18 carats fine. They are hard,
but tough and ductile, and become soft by immersing in
cold water. No. 5 is Maillechort, made in Paris. It is
quite malleable and takes a high polish when heated ; it
loses twelve per cent, and becomes whiter. Nos. 6 and
7 are alloys recommended by Gersdorff of Vienna, the
first for forks and such articles, the second for such
objects as require soldering. No 8 is, according to Mr.
Topping, of London, the commonest of German silver,
fit only for wire and articles of inferior value. If the
quantity of nickel is brought much below this, the alloy
will be little better than pale brass, and will tarnish
rapidly. The same authority highly recommends No. 9,
360 ALLOYS OF COPPER.
as being very beautiful, and little inferior to silver that
is nearly standard. No. 11 is the richest alloy that can
be made without injuring the mechanical properties of
the metal.
Tutenag is an alloy in frequent use among the
Chinese. It is very fusible, but hard, and not easily
rolled, and therefore answers better for castings. Its
composition is
Copper, 40.7
Nickel, 17.4
Zinc, 36.9
100.0
This alloy is prepared, like brass, in pots or crucibles,
and much of the zinc is lost. The only way in which
the bad effects of. this can be obviated, is by taking a
larger quantity of the volatile metal, to allow for the
waste. The metals are usually stratified in the crucibles,
the lowermost and topmost layers being copper, and the
whole being covered with charcoal powder or pulverized
glass. When fused, the metals should be thoroughly
incorporated by stirring with a porcelain rod. When
fragments of German silver are fused a second time,
more zinc must be added ia order to make up the loss
just alluded to.
BRONZE. This compound is essentially an alloy of
tin and copper, though other metals are introduced in
practice. It is one of the oldest known alloys. The
so-called copper tools found in Egyptian quarries, which
have elicited so much ignorant admiration from anti-
ALLOYS OF COPPER. 361
quarians, are in reality composed of tempered bronze.
The ancient swords were made of this alloy. A sword
found in the peat moss of the Somme, contained of cop-
per 87.47, tin 12.53. Another, found near Abbeville,
was composed of 85 copper to 15 tin, and another of 90
of copper to 10 of tin. The bronze springs of the balistae
contained 97 of copper and 3 of tin.
The application of this compound to the casting of
statues, also dates from a very remote antiquity. It
was, however, first brought to something like perfection
by Theodorus and Roecus, of Samos, about seven hun-
dred years before the Christian era. In the reign of
Alexander of Macedon, the celebrated artist, Lysippus,
gave a new impulse to this department of art, by his
improvements in moulding. He made six hundred
bronze statues of his great patron, and this wholesale
manufacture gave rise to Pliny's sneer " The mob of
Alexander." Colossal statues were afterwards made
from this same metal, the most celebrated of these be-
ing the well known Colossus of Rhodes. Some idea
may be formed of the great demand for bronzes, from
the fact that the Roman Consul, Mutianus, found three
thousand bronze statues at Athens, eight thousand at
Rhodes, and as many at Olympia and Delphi, though
from the latter place a great number had been removed
before his arrival.
It must not be supposed, however, that the ancients
possessed the skill of the moderns in the management
of this metal. Having no means of ascertaining with
certainty the actual composition of these alloys, they
could not provide against the oxidation of the tin, and
31
<ib2 ALLOYS OF COPPER.
consequent refining of copper, which is one of the great
difficulties in the working of this alloy. Consequently,
analysis has shown that their bronzes are of very vari-
able composition, some of them containing the proper
quantity of tin, and others being nearly pure copper.
Indeed, this difficulty has not always been overcome
in modern works. The statue of Desaix, in the Place
Dauphine*, and the great column in the Place Vendome,
are signal instances of failure in this respect. On ana-
lyzing, separately, specimens taken from the bas-reliefs
of the pedestal of this column, from the shaft, and from
the capital, it was found that the first contained six per
cent, of tin, the second much less, and the third only
0.21 per cent., being nearly pure copper. Hence, it
appears that the unskilful founder had gone on refining
the copper by the oxidation of the tin until he had ex-
hausted his copper, and that he had then worked up the re-
fuse scoriae in the upper part of the column. The cannons
which the government furnished him were composed of
Copper, . . . 89.360
Tin, .... 10.040
Lead, .... 0.102
Silver, zinc, iron, and loss, 0.493
100.000
The moulding of the several bas-reliefs was so badly
done that not less than seventy tons of bronze was re-
moved by the chisellers employed to repair the faults.
Bronze is more fusible than copper, and, as in the
last described alloy, its density is greater than the mean
of its constituents. This, however, does not appear
when the specific gravity is taken of bronze in bulk,
ALLOYS OF COPPER. 363
since its vesicular structure interferes with the accurate
estimation of its density. For this reason, the experi-
ment must be performed, not upon a solid piece of the
alloy, but upon its fine powder. Some of its forms are
malleable, especially that composed of eighty-five parts
of copper and fifteen of tin. Other varieties, made of
different proportions of the constituent metals, may ac-
quire malleability by tempering, which lessens their
density and hardness, and sometimes renders them more
tenacious. The following table exhibits, at a glance,
the effect of this process upon different bronzes :
Composition of alloy Copper, 95 90 85 80 75
Tin, 6 10 15 20 25
100 100 100 100 100
Density before tempering 7.92 8.08 8.46 8.67 8.57
after " 7.S9 8.00 8.35 8.52 8.31
Hardness before tempering, 100 100 100 100 100
" after " 99 98 96 92 91
Sample % line in thickness, before tempering, tenacity, 80 66 48 50 70
after " " 100 100 100 100 100
Sample 8 lines thick, before tempering, tenacity, . 100 100 80 80 100
" " " after " " . 75 78 100 100 35
We have already alluded to the difference made in
samples of bronze by the oxidation of zinc. The fol-
lowing table expresses the change effected by a series of
successive fusions.
Number Weight of
Composition.
ons.
ounces.
Loss per cent.
Specific gravity.
Copper.
Tin.
1
268
1.2
8.565
90.4
9.6
2
236
1.6
8.460
90.7
9.3
3
204
2.1
8.386
91.7
8.3
4
172
2.5
8.478
92.8
7.2
5
140
2.6
8.529
93.7
6.3
6
104
3.0
8.500
95.0
5.0
364 ALLOYS OF COPPER.
It is not, however, only the loss in weight, and the
change consequent upon the diminution of the proportion
of tin which measures the deterioration of the hronze.
There remains mingled with it a greater or less quantity
of the oxidized metals, impairing its tenacity and its ca-
pacity for wear. This is easily remedied by fusing it with
the necessary quantity of tin and some charcoal, and, if
required, by poling the bath as in the refining of copper.
Another peculiarity of bronze, when cast in sand
moulds, especially if they be large, is, that shortly after
casting, a jet of liquid metal flows out from the interior,
either at the sides or the upper surface of the metal.
It has been suggested, to account for this phenomena,
that the first part of the alloy which comes in contact
with the walls of the mould, condenses, contracts, and
displaces the new-expanded molten metal within, which
exudes laterally when the pressure of the metal from
above is very great, but rises, if this weight is not suffi-
cient to keep it down. The escaping metal is richer in
tin than the solidified alloy.
The effect of introducing other metals besides tin, is
often beneficial. Iron is thought to improve the charac-
ter of the alloy, rendering it harder and tougher, as
well as less fusible. The latter quality is an advantage
when casting in sand moulds, as such an alloy is less
liable to the formation of cavities, since the matter im-
mediately solidifies upon coming in contact with the
walls of the moulds, and does not allow the entrance of
air into the fluid mass, as takes place with the ordinary
bronze.* Zinc is held to produce similar results, and
* The iron is not introduced in its pure state, as in that case it will not
combine with the alloy. It must be added in the form of tinned plate.
ALLOYS OF COPPER. 365
is also thought to give a fine bronze tint, when added
in the proportion of two or three per cent, of the entire
composition. Lead is considered detrimental to bronze,
because it is so readily oxidized as to act as a scorifier
upon the other metals. Besides this, its great specific
gravity causes a precipitation of the copper towards the
bottom of alloy, producing irregularities in the casting,
especially in large works.
" For many of the uses to which bronze is applied in
the arts, its composition is altered; thus, for wheel-
boxes or sockets, the alloy contains
Copper, . . 80
Tin, ... 18
Zinc, ... 2
100
" The fracture of this alloy is nearly white ; it has a
dry grain, and is very hard, but still may be worked.
The zinc is added with the view of preventing cracks,
which are apt to form in the casting, owing to the con-
traction of the alloy upon cooling.
" Another alloy intended for a similar use, and for
the collars of motive cylinders, has the following com-
position :
Copper, . . 82
Tin, ... 16
Zinc, ... 2
100
81*
366 ALLOYS OF COPPER.
" This is somewhat more malleable than the preceding,
so that when the collar is being forced on to its place,
it is less liable to break.
" An alloy, when required to resist powerful friction
and sudden shocks, is made of the annexed propor-
tions :
Copper, . . 83.0
Tin, . . 15.0
Zinc, . . 1.5
Lead, . . 0.5
100
" For pump-boxes, and such articles as require to be
brazed or soldered, the proportions are
Copper, . . 87
Tin, . . 12
Zinc, . . 1
100
" This alloy, when broken, presents a reddish frac-
ture, with a fine grain. It is malleable, but not suffi-
ciently so as to answer for the material of stop-cocks,
pump-valves, and the like, which are subject to receive
concussions, et cetera, that would endanger the safety
of the article, unless it were sufficiently pliant to resist
them. Compositions of this nature contain
Copper, . . 88
Tin, . . 10
Zinc, . . .2
100
ALLOYS OF COPPER. 367
" This alloy has a fine grain, and is capable of receiv-
ing a high polish ; it has a rich red color."*
Bronze for statues should possess several qualities.
It should be capable of flowing into all parts of the
mould, however minute ; it should be hard, that it may
resist accidental blows ; it must be of such a composi-
tion as to resist the action of the weather, except to the
extent of forming upon its surface that greenish coat
so much admired in ancient bronzes, and called patina
antiqua. The brothers Keller, the famous founders of
the time of Louis XIV., are celebrated for their success
in this kind of statuary. The following tables express
the results of the analysis of different statues from their
foundry :
1. 2. 3. Mean.
Copper, 91.30 91.68 91.22 91.40
Tin, 1.00 2.32 1.78 1.70
Zinc, 6.09 4.93 5.57 5.53
Lead, 1.61 1.07 1.43 1.37
100.00 100.00 100.00 100.00
The analysis of the statue of Louis XV. gave the
following results :
Specific gravity, 8.482
Copper, . . . 82.45
Zinc, .... 10.30
Tin, .... 4.10
Lead, .... 3.15
100.00
* Muspratt, op. cit.
368 ALLOYS OF COPPEE.
The properties required in medals resemble those just
mentioned as essential to statues. It should be hard
enough to resist wear and tear, and yet should possess
the opposite property of sensitiveness to the die. The
art of tempering enables the manufacturer of medals to
combine these two opposite qualities. Modern medals
are said to be far less able to resist the oxidizing agen-
cies of the atmosphere than those of ancient coinage.
The reason assigned for this is that too much copper is
used in the modern works of this kind, and this metal
is always softer and more prone to oxidate than an
alloy made with a proper amount of tin. The propor-
tion of tin commonly used, varies from seven to eleven
per cent., though this sometimes goes as low as four,
and rises as high as seventeen per cent. The best pro-
portion is considered to be from eight to twelve per
cent., and it is said if two or three per cent, of zinc is
added, the bronze tint of the alloy is greatly improved.
Medals are usually cast in fine sand, and finished
afterwards by striking them up with a die. Many pre-
cautions are requisite to success in the process of cast-
ing ; but these belong rather to the mechanical than the
chemical department of the subject. Suffice it to say,
that the sand must be so arranged as to give a sharp
impression, and to dry speedily a property that is ob-
tained, in the first instance, by sprinkling the surface
upon which the impression is to be made, with finely
powdered charcoal bone-ash or slate and in the sec-
ond, by making the exterior of coarser sand, and having
the whole as thin as possible. It is also necessary to ob-
viate the concentration of the casting, which sometimes
ALLOYS OF COPPER. 369
makes a difficulty in the subsequent use of the die. This
is effected either by making allowance for this contrac-
tion in the mould, which is larger than the die, by the
calculated amount of shrinking. An exterior coating
of a different metal has been recommended. Lead
paper has been suggested ; but the inconveniences of
working it make it impossible to use it. As a substi-
tute, tinning the model has been resorted to. The coat
thus deposited, though very thin, is yet sufficient to
make up for the contraction.
These precautions having been observed, the compound
metal is fused in a small wind furnace, in crucibles con-
taining ten or twelve pounds each, and is poured into
the moulds at such a degree of heat as will not injure
their outline. This is a nice point to hit, and the neces-
sary skill can only be acquired by experience. If the
metal be too cool it flows badly in the mould ; if too hot
it acts upon the moisture of the sand, disengaging vapors
which give a blistered, irregular appearance to the cast-
ing. When it has attained the proper degree of heat,
it is coated with a smooth layer of oxide, beneath which
the metal is brilliantly white. If the heat be too feeble,
the oxide on the surface will be uneven and tarnished ;
if it be too high, the oxide will fuse and assume, like the
metal, a luminous appearance.
The moulds having been filled, the castings should be
removed as soon as possible and thrown into water to
anneal them. After receiving the impression of the
die, they are again heated that they may regain the
hardness and durability of bronzes.
It is customary to finish up the medals by giving
370 ALLOYS OF COPPER.
them a surface resembling that of ancient bronzes.
This is effected by boiling them in a solution of chloride
of ammonium and acetate of copper. A film of oxide
of copper is thus deposited upon the surface which varies
in depth of color in proportion to its thickness. If the
metal be rich in tin, this result is not easily accom-
plished ; but if zinc be present the effect can be easily
produced by rubbing its surface with a powder consist-
ing of sand and some copper salt. Sometimes the fol-
lowing ingredients, digested in dilute nitric acid are
used ; they must be applied with the brush. Common
vinegar, ninety parts ; sal ammoniac nine, and powdered
green one, will give the color of antique bronze. For
Florentine bronze, eight parts of alcohol and two of red
lead, are digested in dilute nitric acid and applied as
above. Another plan is to dissolve in a quart of vinegar
three-fourths of an ounce of sal ammoniac, and one and
a-half drachms of binoxalate of potash, (salt of sorrel)
and to apply to the bright surface of the thoroughly
cleansed metal by rubbing with a soft rag or brush till
perfectly dry. The process must be repeated till the
full effect is obtained.
Dr. Ure recommends for giving an antique appear-
ance, a solution of one part of sal ammoniac, three of
cream of tartar, and six of common salt in twelve of
hot water, the whole to be mixed with eight parts of a
solution of nitrate of copper of specific gravity 1.160.
"This compound, when applied repeatedly in a mode-
rately damp place to bronze, gives it in a short time a
durable green coat, which becomes by degrees very beau-
tiful. More salt gives it a yellowish tinge, less salt a
ALLOYS OF COPPER. 371
bluish cast. A large addition of sal ammoniac accele-
rates the operation of the mordant."
Ordnance or Cannon Metal. This alloy is composed
of eighty-eight or ninety parts of copper and ten or
twelve of tin, to which proportions the founder generally
strictly confines himself. The metals must be absolutely
pure, as the smallest quantities of sulphur, lead, iron or
arsenic would seriously impair the alloy, perhaps to the
extent of rendering the cannon useless. Lead, as has
already been stated, renders bronze soft and diminishes
its tenacity, and besides the fusion point of such an
alloy is so low that the heat developed by the firing of
the piece would melt it to such an extent as to occasion
inequalities, which would be very dangerous. Sulphur,
arsenic or iron would, of course, confer upon the alloy a
brittleness totally incompatible with the purposes for
which it is to be employed.
Furthermore, the tin itself may be used in such pro-
portions as to produce the faults of over-hardness and
want of tenacity. Even when these proportions are
exact, a practical difficulty occurs in the casting, owing
to the tendency of the metals to separate according to
their specific gravity. This separation occasions serious
defects in the guns, as those portions of them Avhich
contain excess of tin and are therefore easily fusible,
assimilate the sulphur of the gunpowder and give rise
to cavities of sulphide of tin, which quickly occasions
incrustations. This cause of defect is obviated by cool-
ing the metal to a certain point before allowing it to
fall into the mould, and by effecting the hardening
within a given time.
It has been ascertained that the same proportions do
372 ALLOYS OF COPPER.
not answer for all pieces of artillery. Thus, eight
pounders require only seven and a-half per cent, of tin,
while twelve pounders and heavier guns are best made
of the proportions already given.
The loss in these castings is very considerable, though
by skill and care it may be, in great part, recovered.
It is laid down as a rule that to obtain one hundred
pounds in the casting, two hundred and twenty pounds
must be fused in the furnace. This is distributed as
follows :
Weight of casting, 100 pounds.
Loss of bronze in the scoria, . . 12J "
Bronze wasted in the debris, . . . 107J "
Bronze employed, 220 "
Owing to this loss of metal and temporary waste it is
evident that the greatest care and skill are necessary
for the proper management of the work. Rules have
consequently been given for the proper proportioning of
the materials used. It is said that, in each charge, one-
tenth of its weight of new or ingot copper should be
used, and that the tin in the shape of ingots should
amount to fifteen per cent, of this. The following
quantities are required to produce twenty-two hundred
pounds of casting :
Ingot copper, .... 488 pounds.
Ingot tin, . ^ fojTjL v , 73 "
Old pieces of bronze, .." f ,T. . 1769 "
Bronze in the waste attending the
manufacture, .'* . ' 2556 "
Total weight of mixture, ^-^p-' 4886 "
ALLOTS OF COPPER. 373
The real loss under proper care does not amount to
ten per cent., and rarely reaches this point, usually not
exceeding six. Cornish or Banca tin is preferred as
being freer from lead than most commercial tin. When
old tin is used, it is absolutely necessary that it should
be subjected to a process of refining before it is intro-
duced into the alloy.
Bell MetaL The standard composition of bells is
seventy-eight of copper and twenty-two of tin, the latter
being usually increased to compensate for the loss by
oxidation. The founder, however, usually employs other
metals to increase the fusibility of the alloy, as well as
its cheapness. The admixture of these foreign metals
undoubtedly impairs the quality of the product, yet for
the reasons just mentioned it is customary to introduce
them. A common formula for the manufacture of bells
is the following :
Copper, . . . ., ..,..; , , j.^i 77
Tin, 21
Antimony, 2
100
The following analysis by Thomson shows the com-
position of English bell- metal:
Copper, ; '^1T ,'.':'"'* .^-V-''- ' 80 '
Tm, . /,;,/,' ;^;.:.f.:;V* i(u
Zinc, .yJv! , : , fi ,- ..; B 3 i ; Jf 5 ' 6
Lead, . . . .,- v : ;c
100.0
32
374 ALLOYS OF COPPEK.
The founder also often introduces antimony and bis-
muth in order to give a more crystalline character to
the alloy as well as to impart a certain tone to the bells.
Berthier's analysis of the bells of the pendules, or
ornamental clocks, made in Paris, gave the following
results :
Copper, 72.00
Tin, . ' . ' :v ' u . ; '*'", '"''V kv . 26.56
Iron, 1.44
100.00
As in the alloys previously described, so in this, new
metal is not always employed. In the working up of
the old bell-metals and this, however, it is necessary
that their composition should be accurately known, so
that the mean of the alloy shall yield a bell of the
required quality. In the preparation of the alloy, the
whole of the tin is not put in at the beginning, about
one-third being reserved for addition when the whole of
the bath is in perfect fusion. About one-tenth more
than the weight destined for the bell must be melted,
this quantity being expended in waste and scorification
during the process.
Cymbal or Tam-tam Metal. Alloys for this purpose
are prepared, as already said, from seventy-eight or
eighty per cent, of copper and twenty or twenty-two of
tin. Newly cast, the alloy of cymbals is grayish white,
with a fine close grain. It is very brittle and less fusi-
ble than bell-metal. The full sonorous property of the
metal is obtained by heating and sudden cooling. The
ALLOYS OF COPPER. 375
fused alloy is cast into moulds, and as soon as the
objects have hardened, they are removed and heated to
a cherry-red in a furnace. They are then placed be-
tween iron discs and plunged into water, where they are
allowed to cool. They are then sufficiently tenacious to
be worked under the hammer. The instruments, having
been thus formed, are now heated and allowed to cool
slowly in the air. In consequence of this treatment
the vibrations of the metal when struck are stronger,
and the sound they emit much louder.
Telescope or Speculum MetalThe standard of this
alloy is :
Copper, 66.7
Tin, 33.3
100.0
From this standard, however, as in the other alloys,
there is much deviation in practice. The color is steel-
white, the alloy is very hard, brittle, and takes a high
polish. As its name implies, it is used in the construc-
tion of mirrors for telescopes and for other uses.
Edwards, as quoted by Ure, gives, in the Nautical
Almanac for 1787, the following directions for making
speculum metal :
" The quality of the copper is to be tried by making
a series of alloys with tin, in the proportion of one hun-
dred of the former to forty-seven, to forty-eight, to forty-
nine, to fifty of the latter metal ; whence the proportions
of the whitest compound may be ascertained. Beyond
the last proportion, the alloy begins to lose in brilliancy
376 ALLOYS OF COPPER.
of fracture, and to take a bluish tint. Having deter-
mined this point, take thirty-two parts of the copper,
melt, and add one part of crass and as much silver,
covering the surface of the mixture with a little black
flux ; when the whole is melted, stir with a wooden rod,
and pour in from fifteen to sixteen parts of melted tin,
(as indicated by preliminary trials,) stir the mixture
again, and immediately pour it out into cold water.
Then melt again at the lowest heat, adding, for every
sixteen parts of the compound, one part of white arsenic,
wrapped in a paper, so that it may be thrust down to
the bottom of the crucible. Stir with a wooden rod as
long as arsenical fumes rise, and then pour into a sand
mould. While still red-hot, lay the metal in a pot-full
of very hot embers, that it may cool very slowly, whereby
the danger of its cracking or flying into splinters is
prevented."
Tinning Copper. The process of tinning copper is
really the formation of an alloy upon the surface of cop-
per. The vessel to be tinned is heated to the point of
fusion of the coating metal, excluding the air to prevent
oxidation, and taking measures to bring the surfaces of
the two metals in contact. Under these circumstances,
combination takes place, provided no other substance in-
tervenes, but as there is usually a thin film of oxide upon
all manufactured copper, this must be removed. Sul-
phuric acid is often employed for this purpose, but the
most common agent is chloride of ammonium. The surface
of the vessel to be cleansed is sprinkled with this salt in
powder, heat is then applied and the powder rubbed over
the whole surface. The heat first dissolves and then
ALLOYS OF COPPER. 377
volatilizes the chloride, a portion of it being decomposed
to form chloride of copper with the reduced oxide. The
chloride is removed by rubbing, leaving a perfectly
bright, untarnished surface. The heat being still kept
up, tin is laid upon the surface, and the operator, with
his pad or cork, rubs it over till the combination is con-
sidered complete. The amount of tin deposited was
found by Proust to vary from one grain to a grain and five
eighths for every square inch of surface. The larger
quantity is made up in part of some tin which has not
been alloyed with the copper but has simply been solidi-
fied upon the surface. This is of no advantage to the
purchaser, and being a loss to the manufacturer, it ought
to be removed. This is easily accomplished by raising
the temperature and pressing well down with the pads,
when the excess of tin will flow off.
Sometimes an alloy of tin and lead is used, on account
of the greater fusibility of that compound and the greater
readiness with which it is applied. This ought not to be
used for vessels intended for culinary purposes, as a very
small amount of lead, daily introduced into the system,
is sufficient to destroy health and life. Proust, it is true,
has made some calculations, based upon experiment, by
which he undertakes to show that the amount of lead
dissolved by the acids of cooking, is very small, even to
the extent of being incognizable to ordinary chemical
reagents, and that, indeed, the tin of the alloy is alone
dissolved, leaving the lead adhering to the vessel easily
recognized by its bluish white tint. There must, how-
ever, come a time when all the tin will be dissolved and
then the lead will necessarily be attacked.
32*
378 ALLOYS OF COPPER.
An improvement in this process has been suggested
by Biberal, in which a compound of tin and iron is
substituted for pure tin, the proportion of iron, in some
instances, rising as high as one to six of tin. The heat
must be as high as redness in order to fuse this and keep
it melted, while it is applied to the surface. The alloy
is applied by placing the end of the ingot upon the heat-
ed plate and rubbing briskly with some pressure. When
the whole has been treated, the vessel is allowed to cool
and any excess or inequality in the tinning is removed
by a scraper. The superiority of this application arises
from the high degree of heat necessary to melt it, its
fusibility, of course, diminishing with the amount of iron
alloyed with the tin.
Recovery of Copper from its Alloys. Our account of
the alloys of copper would be incomplete, were we to
omit to describe the method by which this metal may be
recovered from its compounds. Its separation from tin
depends entirely upon the greater oxidability of the lat-
ter metal. Fourcroy's method of separation consisted,
first, in thoroughly calcining the alloy in a reverberatory
furnace, and finely powdering the resulting oxide. A
fresh quantity of alloy was then melted in the same fur-
nace, and to it was added one half its weight of the oxide.
The temperature was increased and the mixture well in-
corporated. At the end of a few hours, copper nearly
pure rested upon the hearth, and a slag comprising the
mixed oxides and some of the earthy matters collected
on the surface. This was raked out and the copper
tapped into proper moulds. The scoriae were levigated,
and the metallic copper separated by elutriation. By
ALLOYS OF COPPER. 379
this process, 50 pounds of copper, containing only one
per cent, of foreign matter, were obtained from 100
pounds of bell-metal.
The washed scoriae were then intimately mixed with
one eighth their weight of pulverized charcoal, and melt-
ed in a reverberatory furnace. The result was an alloy
of 60 parts of copper and 40 of tin, together with slags
richer in tin than those of the previous operation. The
alloy thus obtained was roasted and melted in the same
furnace. The air sweeping over the surface oxidated
the tin more rapidly than the copper, and the surface of
the metal was covered with a coat of oxide. This was
skimmed off from time to time, till the metal had reach-
ed the standard of bell-metal, when it was run out and
subjected to the whole process again.
M. Briant improved this process by substituting eli-
quation for some of the roasting. By fractioning the
products flowing off during the process, he obtained,
firstly, tin with lead ; secondly, tin nearly pure ; and
lastly, tin alloyed with some copper. The spongy mass
which remained on the sole, was treated by oxidation.
By this process he not only incurred less loss of tin, but
also consumed less fuel and obtained purer products of
known composition, applicable directly to the purposes
of the arts.
APPENDIX.
STATISTICS OF COPPER.
The most interesting facts in regard to the produc-
tion of copper will now be given in a tabular form.
The tables are taken from "Whitney's Metallic Wealth
of the United States, altered by collation with the tables
published in Muspratt's Chemistry, and continued from
the published accounts of the ticketings at Cornwall and
Swansea.
As Great Britain occupies so important a position
among the producers of copper, the statistics of her pro-
duction are first given.
TABLE I.
PRODUCTION OF CORNWALL FROM 1726 TO 1775 INCLUSIVE.
Years.
Tons.
Av'rage price
per ton.
Amount
Av'age amt.
prod tons.
Av. annual
value.
1726,1
1738, /
64,800
t. d.
1 15 10
473,500
6,480
47,250
1736,1
1745, /
75,520
786
560,106
7,552
56,010
1746,1
1755,/
98,790
780
731,457
9,879
73,145
1756,1
1765,/
169,569
766
1,243,045
16,970
124,304
1766,1
264,273
6 14 6
1,778,337
26,427
177,833
382
APPENDIX.
TABLE II.
PRODUCTION OF CORNWALL FROM 1771 TO 1857, TEAR ENDING JCNE 30.
Tears.
Tons of ore.
Tons of cop-
Value In pounds
Standard.
Percent.
per.
Sterling.
yield.
1771,
27,896
3,347
189,609
81 05.1
1772,
27,965
3,356
189,505
81 00
1773,
27,663
3,320
148,431
70 00
12
1774,
30,254
3,630
162,000
68 00
1775,
29,966
3,596
192,000
78 00
1776,
29,433
3,532
191,590
79 00 =
1777,
28,216
3,386
177,000
77 00
1778,
24,706
2,965
140,536
72 00
1779,
31,115
3,734
180,906
73 00
1780,
24,433
2,932
171,231
83 00
1781,
28,749
3,450
178,789
77 00
12
1782,
28,122
3,375
152,434
70 00
1783,
35,799
4,296
219,937
76 00
1784,
36,601
4,392
209,132
72 00
1785,
36,959
4,434
205,451
71 00
1786,
39,895
4,787
237,237
75 00.
1787,
38,047
....
190,738
1788,
31,541
150,303
1789,
33,281
184,382
1790,
1791,
1792,
1793,
1794,
42,816
320,875
1795,
43,589
336,189
1796,
43,313
4,950
356,564
1797,
47,909
5,210
377,838
1798,
51,358
5,600
422,633
1799,
51,273
4,923
469,664
121 00
1800,
55,981
5,187
550,925
133 03
1801,
56,611
5,267
476,313
117 05^
1802,
53,937
5,228
445,094
110 18
1803,
60,566
5,616
533,910
122 00
Q Q
1804,
64,637
5,374
570,840
136 05
o.o
1805,
78,452
6,234
862,410
169 16
1806,
79,269
6,863
730,845
138 05 >
1807,
71,694
6,716
609,002
120 00 "
1808,
67,867
6,795
495,303
100 07
1809,
76,245
6,821
770,028
143 12
91
1810,
66,048
5,682
569,981
132 05
.1
1811,
66,499
5,948
563,742
126 00
1812,
75,510
7,248
608,065
113 00 ;
APPENDIX.
TABLE II. Continued.
383
Years.
Tons of ore.
Tons of cop-
per.
Value in pounds
Sterling.
Standard.
Per cent,
yield.
1813,
86,713
8,166
685,572
113 Qs.-]
1814,
87,482
7,936
766,825
128 00
1815,
79,984
6,607
582,108
121 00
1816,
83,058
7,045
541,737
109 00 '
9.5
1817,
75,816
6,608
422,426
96 00
1818,
80,525
6,714
587,977
121 00
1819,
93,234
7,214
728,032
136 00 :
1820,
92,672
7,364
620,347
119 00
1821,
98,803
8,163
628,832
111 00
1822,
106,723
9,331
676,285
104 00 '
8.1
1823,
97,470
8,070
618,933
110 00
1824,
102,200
8,022
603,878
110 00
1825,
110,000
8,417
743,253
124 00 :
1826,
118,768
9,140
798,790
123 00
1827,
128,459
10,450
755,358
106 00
K /\
1828,
130,866
9,961
759,175
112 07 '
7.y
1829,
125,902
9,763
725,834
109 14
1830,
135,665
10,890
784,000
106 15
1831,
146,502
12,218
817,740
99 18 :
1832,
139,057
12,099
835,812
104 14
1833,
138,300
11,185
858,708
110 00
Q -1
1834,
143,296
11,224
887,902
114 04
O.I
1835,
153,607
12,271
896,401
106 11
1836,
140,981
11,639
957,752
115 12
1837,
140,753
10,823
908,613
119 05
1838,
145,688
11,527
857,779
109 03
1839,
159,551
12,451
932,297
110 02
7.8
1840,
147,266
11,038
792,758
108 10
7.5
1841,
135,090
9,987
819,949
119 06
7.4
1842,
135,581
9,896
822,870
120 16
7.3
1843,
144,806
10,926
804,445
110 01
7.5
1844,
152,667
11,247
815,246
109 17
7.4
1845,
157,000
12,293
835,350
103 10
7.8
1846,
158,913
12,448
886,785
106 08
7.8
1847,
148,674
11,966
830,739
103 12
8
1848,
155,616
12,870
825,080
97 07
8.3
1849,
144,933
12,052
716,917
92 12
8.3
1850,
150,890
11,824
814,037
103 19
7.8
1851,
154,299
12,199
808.244
101 00
7.9
1852,
152,802
11,706
828,057
106 12
7.6
1853,
180,095
11,839
1,124,561
136 15
6.5
1854,
180,687
11,779
1,153,756
6.6
1855,
195,193
12,577
1,263,739
6.8
1856,
209,305
13,275
1,283,639
1857,
289,768
18,915
1,816,644
384
APPENDIX.
TABLE III.
This table gives the productiveness of the United Kingdom down
to 1835, with accuracy; from that down to 1848, the statement is only
approximate, as the British copper cannot be certainly separated from
that of foreign origin.
Tears. Tons of copper. Tears. Tons of copper.
1820,
1821,
1822,
1823,
1824,
1825,.
1826,
1827,
1828,
1829,
1830,
1831,
1832,
1833,
1834,
ans of copper.
Tears.
8,127
1835,
10,288
1836,
11,018
1837,
9,679
1838,
9,705
1839,
10,358
1840,
11,093
1841,
12,326
1842.
12,188
1843,
12,057
1844,
13,232
1845,
14,685
1846,
14,050
1847,
13,260
1848,
14,042
14,470
14,770
10,150
12,570
14,670
13,020
12,850
14,840
14,900
14,950
13,780
14,720
The above is taken from Whitney, who quotes it from G. R. Porter's
Progress of the Nation, London, 1851.
TABLE IV.
Also from Whitney, expressing the productiveness of the new
srorld, approximately in tons of copper.
Tears. Chili. S America. Cuba. U. S. & Canada
1830,
1835,
1840,
1845,
1846,
1847,
1848,
1849,
1850,
1851,
1852,
1853,
1854,
700
9,000
.... 4,500
....
13,270
.... 6,800
100
13,800
.... 5,150
150
11,850
.... 4,000
300
12,275
.... 4,000
500
12,450
.... 3,600
700
1,200 3,400
650
3,400
900
2,600
1,100
1,300 2,500
2,000
APPENDIX.
385
Ill
Years.
5'
||
li-
|S
: : : III: :::::
Rnsssia.
ill
g- ^ 3
:::{::: ::.:::
Sweden.
1|
^ H p
p
S* s
I|.|
iiiliilfSliiii
Norway.
ES*
O
3f 3
s*
ST 2 ^.
:
G. Britain.
s 3
p s S-
_ i.,^^
^
S O, <r-
iislsSSIIIS::
Prussia.
o | a
ego
3 "
:::S: :::::!!;
Hartz.
1
Iff
: : 0: &: : : HB6: :
Saxony.
Di
2
!*
CO ,, ,-.
Austria.
S
5
^^
-
CD
g ^
II
I i :::::: Sa8Si
France.
c
J 1
: : : : g: g: g: : : : :
Spain.
<s
e. 8
S
^
M
^ I
g
2,
N S
r
: fe: : : : : ::::::
Turkey.
^
g*
*,
g : r ; : :
Algiers.
5
^ S"
jr]
o
I!
;;;!;!!;;;; i;
Asia.
3
00
II
ig
iiiiiliil : i !
Australia.
o
4
3
s
5' c^
g >
S I'
:: 3 8g8^i [:
N. Zealand.
1
33
386
APPENDIX.
Years.
1835,
1840.
1845^
1846,
1847,
1848,
TABLE VI.
PRODUCE OP CUBA IN TONS OF COPPER.
Tons of copper. Yearn.
681
4,139
6,352
4,092
3,867
Tons of copper.
. 3,594
. 3,239
. 3,300
. 2,500
. 2,200
TABLE VII.
Sales at Swansea in tons of ore of 2] cwt., specifying the country
in which they were raised.
1
i
|
a
!
t
2
>H
1
1
1
X
eS
=
i
1
o
I
!
CJ
1
R
3
3
1S2S,
3,875 8 510
199 1
12,584
1829,
6,796
7,044
456
187
25
14,508
1830,
2,203
9,115
733
201
12,252
1831,
1,982
9,707
674
244
'*57
12,664
1832,
3,830 11,399
531
33
**
is
62
15,870
1833,
2,147 11,293
624
435
...
14,499
1834,
3,713 17,280
453
1,107
517
23,070
1835,
4,038 22,123
329
2,342
4,0>7
....
32,919
1836,
2,233 21,013
1,099
4.402
3,106
20
"4l9
32,292
1837,
2,395 22,306
1,277 1 6,'825
6,405
14
39,222
1838,
4,374] 22,161
i,023 1 10,924
7,725
*196
46,403
1839,
4,449! 23,613
479 1 8,436
15,148
....
29
52,154
1840,
1,277 i 20,166
55 10,325
24,831
140
3
57,797
1841,
1,885 | 14,321
38
10,395
30,864
....
67
67,570
1842,
2,767 i 15,253
36
9,475
34,562
69
250
62,412
1843,
1,889 l 17,600
11,550
28,071
'.'.'.'. 61
1,057
60,228
1844,
1845,
2,130
2,536
20,063
19,647
11,857
4,755
33,331
39,270
61 10
1,635 395
232
66,684
68,826
1846,
1,684
17,553
7,721
27,279
3,232 675
441
58,485
1847,
746
14,373
5,795
21,918
6,321
407
1,259
50,819
1848,
774
12,633
4,163
25,778
5,891
121
49,360
1849)
1,677
9,852
923
23,282
7,552
307
43,593
1850,
1,574
10,478
1,537
21,591
4,561
1,972
41,713
1851,
592
11,678
827
21,692
2,238
ai9
2,502
39,838
1852, I 1,504
10,104
89
892
16,177
1,356
513
1,019
31,654
1853, 2,174
11,367
1,203
14,058
1,040
1,046
2,086
32,974
Total, 65,144
390,652 | 8,095 j 116,554
399,692
33,977
3,609
12,667
1,030,390
APPENDIX.
TABLE VIII.
387
SALES AT SWANSEA FOR THE DIFFERENT QUARTERS, FROM 1853.
1853.
Quarter to March 31,
" June 30,
" Sept. 30,
Dec. 31,
1854.
Quarter ending March 31,
" June 30,
" Sept. 30,
" Dec. 31,
1855.
Quarter ending March 31,
" June 30,
Sept. 30,
Dec. 31,
1856.
Quarter ending March 31,
" June 30,
" Sept. 30,
Dec. 31,
1857.
Quarter ending March 31,
" June 30,
" Sept. 30,
" Dec. 31,
Tons of ore. Amount of money.
5,119
8,444
10,089
9,332
32,974
6,280
13,200
11,262
13.161
43,903
11,741
10,217
10,761
9,471
42,190
9,976
9,350
11,789
6,542
. d.
91,622 11 6
115,441 7 6
123,801 10 6
146,996 9
477,861 18 6
7,037 103,838 15 6
9,708 134,294 2
10,921 145,282 2 6
9,017 134,691 5
36,683
518,106 5
94,669 15
199,083 6 6
171,114 10
189,660 9
654,468 1
186,890 10
150,757 13
148,347 6 6
142,474 8
169,320 9 6
143,702 5
172,852 17
89,144 2 6
575,019 14
The falling off in this last quarter is due to deficiency in receipts
from Cuba, and to the fact that smelting works have been more ac-
388 APPENDIX.
tively engaged on the west coast of South America, as well as to the
low price of copper, and general depression of business.
Not being able to obtain satisfactory accounts of the productive-
ness of the Lake Superior region, I have not introduced any thing
concerning the mines of that district.
Of the copper smelting establishments of the United States I have
no statistics.
Baltimore turns out about 8,000,000 pounds of refined copper an-
nually.
8 8 3 4 5
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