THE PROSPECTOR'S HANDBOOK THE PROSPECTOR'S HANDBOOK A GUIDE FOR THE PROSPECTOR AND TRAVELLER IN SEARCH OF METAL-BEARING OR OTHER VALUABLE MINERALS ]. W. ANDERSON, M.A. (Cantab.), F.R.G.S. AUTHOR OF "FIJI AND NEW CALEDONIA*' dftfttinn. LONDON CROSBY LOCKWOOD AND SON 7, STATIONERS' HALL COURT, LUDGATE HILL I9II [All rights PRINTED BY WILLIAM CLOWES AND SONS, LIMITEIX LONDON AND BECCLES. PREFACE. To the lover of natural history, no matter in whatever part of the world he may travel, each tract of country offers object after object, subject after subject, of interest. He reads sermons in stones and rocks wherever fate happens to direct his footsteps ; and, if he wanders over the bypaths of untrodden ground, derives a pleasure and satisfaction from the wonderful works of nature, such as no one who has not been privileged to experience it can realise. Geological formations, strange to the eye accustomed, perhaps, to some particular locality, continually attract his attention ; while each river-bed, each mountain-side, and each precipice merits an inspection, if not a close exami- nation. Accompanied by very many hardships and dangers though the life of a prospector must necessarily be, it doubtless possesses an intrinsic fascination ; certainly there must be some extraordinary charm about his free-and-easy manner of living ; he constantly, during his arduous and hazardous explorations, is buoyed up with the pleasing hope of, some day in the future, he knows not how soon or how late, being fortunate enough to reap a reward for his plodding labour, or, using his own phraseology, to " strike something rich." After traversing the mineral fields of New Zealand, New Caledonia, New Mexico, and Colorado, I feel fully con- vinced that some simple guide or handbook for the use of VI PREFACE. prospectors as well as travellers is a desideratum. The ordinary miner or prospector discards a lengthy descriptive work on Mineralogy, containing an account of all the known minerals, the majority of which are perfectly useless to him in his struggle for existence ; and again, elaborate means of dealing with his specimens appear only like a puzzle. It is for this reason that I have endeavoured to treat the subject hi as brief, though as comprehensive, a manner as possible ; and I hope that these pages will satisfy the requirements of at least some of those toilers who explore the trodden or untrodden tracks on the face of the globe. I cannot conclude these prefatory remarks without acknowledging with gratitude my indebtedness to many valuable works to which, by the kind permission of the author or the publisher, I have had access. Among these I would especially mention Mr. Robert Hunt's great work, II British Mining;" Mr. D. C. Davies's two comprehensive treatises, entitled respectively " Metalliferous Minerals and Mining " and " Earthy Minerals ; " and Lieut.-Col. Boss's recently published work, " The Blowpipe in Chemistry, Mineralogy and Geology." I have also had the privilege of borrowing certain illustrations from these and other works, which I feel sure have greatly added to the value and usefulness of my pages. October, 1886. PREFACE TO THE TWELFTH EDITION. IN preparing the twelfth edition of the late Mr. Anderson's " Prospector's Handbook," I have endeavoured to keep it within the bounds of what it professes to be a handbook, and would refer his numerous readers for additional in- formation, or the deeper study of mining, to the more exhaustive works issued by the same publishers. I have combined the valuable notes contained in the preface to the seventh edition in the body of the book, and in revising the glossary I have relied not only upon myself, but also upon the valuable glossary written by Mr. F. Danvers Power for his " Pocket Book for Miners and Metallurgists," * in so far as the terms are applicable to the intention of this work, Should the reader fail to find a reference in the index, he would do well to consult the glossary. That this work has been helpful and beneficial in the past, to those for whom it is written, is evidenced by its success. E. HENBY DAVIES, F.G.S. October, 1908. * Crosby Lock wood and Son. CONTENTS. PAGE Preface to First Edition . . v, vi Preface to Twelfth Edition . vii CHAPTER I. PROSPECTING. Prospecting for valuable minerals. In alluvial deposits. In veins or deposits other than alluvial. Age of lodes. Shoding. Detached portions of a lode. Proving continuity of a lode. Vicissitudes of mining. Necessity for a proper assay. The value of a lode dependent on several circumstances CHAPTER II. ROCKS. Rocks classified.- Superposition of stratified rocks. Lamination. Stratification. Denudation. Cleavage. Joints. The condition under which metal-bearing deposits are found. Nature of mineral veins in a lode, &c. Dip. Strike. Clinometer. Compass 13 CHAPTER III. TESTING MINERALS T THE BLOWPIPE. Apparatus required. How to use the blowpipe. Nature of the flames. Methods of testing in an open tube and a tube closed at one end. On charcoal with carbonate of soda. With borax and microcosmic salt on platinum wire. Beactions CONTENTS. with borax and microcosmic salt. Testing with Nitrate of Cobalt. General table (for the qualitative analysis of metallic substances). Confirmatory tests. To detect certain common substances associated with metals. Temporary blow- pipe . . . . ,.... . .24 CHAPTER IV. THE CHARACTER OF MINERALS. External characteristics. Tables for the determination of the nature of a mineral by noting its colour, lustre and streak. Specific gravity. Hardness. Crystallization . . .32 CHAPTER V. METALS AND METALLIC ORES THEIR CHARACTER- ISTICS TEST1NQ OCCURRENCE, ETC. General remarks. Aluminium; beauxite; cryolite. Antimony; sulphide. Bismuth. Chromium ; oxide. Cobalt ; tin white; earthy oxide. Copper ; native; glance; pyrites; grey ; ruby ; black oxide ; silicate ; malachite. Gold ; detec- tion of and distinguishing tests ; peculiarities ; panning out ; mechanical assay ; sluicing ; native gold. Iron ; pyrites ; magnetic pyrites ; arsenical pyrites ; haematite ; magnetic iron ore ; brown iron ore ; franklinite ; vivianite ; copperas ; spathic ore. Lead; galena; carbonate; pyromorphite ; chromate ; sulphate ; rough method for obtaining lead from galena. Manganese; black oxide; wad, &o. Mercury; native ; cinnabar ; chloride ; selenide ; to obtain metal from ore. Nickel ; kupf ernickel ; white ; emerald ; hydrated silicate. Platinum ; native. Silver ; native ; brittle ore ; glance ; hornsilver ; ruby ore ; silver in carbonate of lead. Tin ; tinstone ; bellmetal ore. Zinc ; calamine ; silicate ; red zinc ore . . . . V, . . . . . .39 CHAPTER VI. OTHER USEFUL MINERALS AND ORES. Black lead. Coal ; anthracite ; bituminous ; brown coal. Bitu- men ; asphalt ; naphtha ; petroleum. Gypsum. Apatite. CONTENTS. xi PAG* Alum. Borax. Common salt. Nitrate of soda ; phosphate of lime ; heavy spar ; fluor spar ; carbonate of lime. Precious stones and gems ; diamond ; table of characteristics of various )ious stones and gems .84 CHAPTER VII. COMPOSITION OF VARIOUS ROCKS. Granite. Schists. Gneiss. Serpentine. Basalt. Pitchstone. Obsidian. Pumicestone. Sandstones. Limestones. Dolomite. Clays. Nature of certain minerals in igneous and metamorphic rocks ; quartz ; felspar ; mica ; talc ; chlorite; hornblende; augite ; olivine. Matrices of veins ; quartz ; fluor spar ; cale spar 99 CHAPTER VIII TESTING BY THE WET PROCESS. Systematic plan of procedure . . . , , . .106 CHAPTER IX. ASSAY OF GOLD. Various methods. Fluxes, reagents, &c. General treatment of ores. Preparation of the sample. Weighing, &c. Assay ton. To construct a simple button- balance and to use it. Dry assay for gold and silver. Apparatus and procedure. Fusion in a crucible. Scorification. Cupellation. Indica- tion of the presence of metals known from cupel stains. To make cupels. Dry assay for lead in galena. Wet assays for gold, silver, lead, copper, iron. Roasting. Mechanical assay of ores ......... 110 CHAPTER X. TREATMENT OF ORES. Metallurgical treatment. Copper from copper pyrites and other sulphides. Lead from galena. Treatment of silver-bearing ores. Gold from lodes and deposits. Concentration of ore . 124 CONTENTS. CHAPTER XL SURVEYING. PAOI To calculate areas. To find the distance from an inaccessible place. To solve problems in connection with adits, shafts, lodes of a mine. Position of a shaft with regard to a lode . 132 APPENDIX. Weights and measures of England, France, &c. "Weights of various rocks and metallic ores. Specific gravity of metals, metallic ores and rocks. Table of natural sines. Melting point of various metals. Table to find the number of ounces of metal to the ton of ore. To find the weight of ore in a lode and the value of a property. Horse power of water . 141 GLOSSARY OF TERMS USED IN CONNECTION WITH PROSPECTING, MINING, MINERALOGY, ASSAYING, &o 155 INDEX . .... .191 THE PROSPECTOR'S HANDBOOK CHAPTEE I. PROSPECTING. Prospecting for valuable minerals. In alluvial deposits. In veins 01 deposits other than alluvial. Age of lodes. Shoding. Detached portions of a lode. Proving continuity of a lode. Vicissitudes of mining. Necessity for a proper assay. The value of a lode dependent on several circumstances. IN prospecting a country for mineral wealth, it is most im- portant to search very systematically and carefully among the sands and rocks of river beds, in dry creeks, and at the bottom of valleys, as well as on the sea-shore.^ Not only does the action of running water and glaciers grind down masses and particles, and, through the never-changing law of gravity, deposit the debris on the lower ground : but also, as on the shores of California, Oregon, New Zealand, and elsewhere, the tides of the ocean distribute the disintegrated heavy metals in a regular fashion. The prospector should observe the characteristics of loose rocks found in ravines or gulches, more especially in eddies or dry waterholes where heavy matter is left during freshets, such as are of frequent occurrence in mountainous districts ; for thejtolfis and._channels and fissures in the solid rock over ^vhich a stream runs, or has run, are frequently well worth examin- ing. All earthy deposits being the result of either chemical or mechanical action, they usually serve as a guide to the nature of the constituent parts of the earth's crust in the immediate neighbourhood. Prospecting for heavy metals left in the form of a deposit is based on one and the same rules, and, consequently, the THE PROSPECTOR'S HANDBOOK. search for the precious metal gold,, may be selected as an exemplification of the method, fin searching the sands washed down by rivers, it is well to bear in mind that if the bed of a river flowing through an open country yields fine gold dust, it will probably yield larger dust or grains nearer the mountains from which the stream runs, and grains of gold far along the stream may suggest nuggets nearer the source ; because the water which has washed the gold-bear- ing matter from the lodes in the mountains has washed it, so to speak, down an inclined plane, leaving in its course the heavy particles and transporting the lighter farther away. The richest deposits are often those where the current has been broken by a change of descent or direction, and where a turning is abrupt, so that on one side of the stream is a cliff and on the other a gentle slope ; the latter may be very rich in heavy metals. Sometimes there are several of these bends with slopes opposite cliffs, and in these slopes there is more chance of discovering gold than in places where the course of the stream is a straight one. The ter- mination of a mountain chain, too, offers a likely site for alluvial diggings. ^Yery commonly in a canon or gulch, where gold grains are found deposited in the lowest parts along which the river or creek runs, an accumulation of boulders or gravel may be noticed higher up the sides of the range, and more or less parallel to the bed of the creek. Portions of such deposits should be carefully examined by the eye (and by the magnifying glass), and by washing in a basin at the nearest water (as hereafter explained GOLD, Chapter V.), as the gold-bearing matter, whether carried there in a past age by running water or glacier, may con- tain rich gold layers close to the " bed-rock " on which the debris rests. Should there be several distinct deposits, the deepest layer of each period is generally the most lucrative. When alluvial ground is made up of rather loose gravel mixed with boulders or lumps of rock, tho gold along with other heavy substances will be found underneath the bulk of the coarse deposits, and either remains near to or on the *" bed-rock," or mixed with clay ; so that the earthy matter just over the "bed-rock " ought to claim much more attention than that elsewhere. PROSPECTING FOR VEINS AND DEPOSITS. 3 If the clay is likely to contain the precious metal, it ought to be washed very carefully. In prospecting a stream, should the flow of water hinder digging operations, the course of the stream must be diverted by means of back trenches, cut so that the water may flow through them ; in this manner the bed may be laid bare, and then the large rocks or boulders can be easily remoyed and the finer gravel thoroughly washed by running water. It is advisable to remember that when gold in alluvial ground occurs, the chances are that auriferous lodes not necessarily payable to work, yet, perhaps, of a far more permanent source of wealth than the gravels will prove traverse the neighbouring elevations of land, and conse- quently the country round about should be searched for veins. In the search for mineral veins or deposits other than alluvial, it is not advisable for a prospector to trouble him- self about the comparatively recent formations nor modern volcanic rocks ; for, although certain deposits do occur in the former, and rich auriferous deposits have been worked in Australia and California under formations capped by the latter, it is well to bear in mind that, excepting certain deposits of iron, copper, zinc, lead, &c., and, of course, sur- face diggings, the metal-bearing minerals are chiefly mined for in the rocks of an older date than those of the Coal measures, though some, as in California, Transylvania, and Hungary, belong to a more recent period. It must also be remembered that a granite, diorite, andesite, or metamor- phic rock (schist, quartzite, &c.) country is always worth prospecting. Without entering into a discussion concerning the forma- tion and origin of veins, about which so much speculation has been rife and so many theories propounded, it suffices to say that certain laws applying to veins in one district apply also, more or less, to those in another. For instance, in any particular district the mineral-bearing lodes generally follow the same direction, that is to say their planes have the same compass-bearing, and consequently are parallel, notwithstanding a considerable distance may separate one lode from the next nearest to it. In some mining districts, a second series of veins runs right across the first and principal ; these lodes, however, are either of a different nature of mineral to that of the first, or if of the same, THE PROSPECTOR'S HANDBOOK. poorer in quality. It is well to recollect that a true mineral vein, where it exists, is not likely to be isolated ; it rather represents, in a poorer or richer degree, many more within reach, and which constitute a " mineral belt." For this reason, the explorer should not set his affections too much on any one " claim " until he has to his own satisfaction, if means and time allow, considered the whole district with its numerous lodes as a mineral-bearing one. In the search for mineral veins, the prospector should study the general geological features of the country, the sections of road cuttings, landslips, precipitous cliffs, the sides of valleys, the sections of banks exposed to view (by the action of water or other denuding agency), river- beds, dry channels and gorges. If he find " likely " stones in a creek or valley, he should travel up it until he notices that similarly constituted stones cease to be seen, and then start up the hill-side to discover the parent rock from which they became detached. Very frequently, while at the base of a hill or mountain, there is a deposit in the form of soil washed down from the more elevated ground, higher up there is "drift" in the form of boulders and detritus, intervening between the surface and the original bed-rock, and thus obscuring the solid rock formation from view. However, by taking note of the various undulations and avoiding such places where common sense suggests that "drift" would naturally accumulate, the prospector may come across "outcrops," especially in the steep sides of gulleys and backbones of ridges ; and, failing this, he may, by travelling towards the summit of any range of hills, be sure, as he approaches the top, to find less " drift " to thwart his investigations. At the same time, though he ought not to be too eager to commence work with his prospecting pick in "drift" of great thickness say ten or twenty feet he must, for all that, carefully notice the various "float " stones on the surface of the hill-sides, as by doing so he can often trace the rim of a particular lode hidden from view, and, if no " outcrop " of the same kind of rock has attracted his attention by leaving traces in the form of detached pieces scattered about the slopes according to the MATRICES OF VEINS. law of gravity, which distributes the pieces as they have been hurled or washed down from the parent rock with a certain amount of regularity the larger and least weather- beaten ones being nearest the lode he can leastways observe at what point up the slope the " float " rock ceases to be seen ; then he may sink a ten-feet-deep pit, or else drive a crosscut to strike the " body " of that which he is in search of. Before commencing this, he must take note of the slope on which the " likely " broken away rocks repose, because FIG. 1. ILLUSTKATION OP A DEPOSIT PURSUING A CUKVILINEAR COURSE. 0, outcrop ; the deposit dipping 60. A shaft sunk at A would cut the deposit at I 7 instead of X, as supposed. judgment may tell him that the parent rock is not directly under his feet, but rather to the right or left, according to the amount of inclination of the hill-side. Much unneces- sary labour is often performed through not taking account of this, as one naturally imagines that the lode is just underneath the line where the greatest amount of "float 77 occurs, whereas it may in reality be several yards distant, probably on the ridge just a little way off, but decidedly not on the other side of it. Sometimes, as is the case with the Transvaal conglomerate, the direction of a deposit near the outcrop may alter con- THE PROSPECTORS HANDBOOK, siderably as depth is gained ; and, where no other outcrops at a distance are observable, much wrong calculation as to FIG. 2. Fm. 3. future prospecting or sinking of shafts, &c., may be the result. (Fig. 1.) Where "faults " occur, the course, of lodes or beds maybe irregular in direction on account of the dislocation of the country rock ; but if the country is made up of different kinds of layers, the deviation may fre- quently be easily determined b}^ the relative position of the beds. (Figs. 2, 3, 4.) In examining the loose rocks on the surface, the expert explorer can often form a tolerably correct notion of the nature of an under- ground lode, despite the fact that exposure to weather entirely alters a piece of rock which once upon a time may have been metallic in appearance before it became dis- connected from its original position. So, in scaling the heights, he casts his glance in every direction, to observe if the " country rock " be " kindly J; for veins, and all the while keeps a sharp look out for that kind of rock known FIG t. MATRICES OF VEINS. to form the matrix of a mineral vein. The matrices are chiefly quartz, fluor spar, and calc spar ; generally quartz. (See Chap. VII.) Fluor spar (fluoride of lime) is favourable for lead and copper, calc spar for lead and silver; but quartz is very nearly the universal matrix of veins in a mineral country, and thus it is that quartz rock should be especially searched for. Very frequently the pieces of quartz broken away from the lode and also the surface portion of the lode are honey- combed. Having been exposed to the influence of the atmosphere and moisture, most of the metalliferous parts once existing in the cavities, and similar to what one might expect to find a few fathoms downwards on the vein, have been decomposed, and so, instead of filling up the honey- comb cavities of the surface quartz, have merely left traces in the form of stains. This only applies to the metallic portions oxidizable, for it is in the surface of honeycombed auriferous rock that the unmistakable yellow specks may be seen in the cells once filled up with iron or copper pyrites or other metallic compound associated with the precious metal. Gold and silver in the native state (the former very much more so than tjie latter, which becomes tarnished) weather the effects of the elements much better than most metals, and an be recognised in the native condition ; but experience alone can acquaint one with the variously shaded blacks, reds, greens, browns, greys, &c., which the metallic sulphides have left behind as oxides and carbonates. One of the best surface indications is the honeycombed rock brown with iron oxide. In the German mining districts there is a saying " Es thut kein gang so gut Er hat einen eisernen hut." (" There is no lode so good as the one which has an iron hat.") And this quite corresponds with the French " cha- peau de fer," and the Cornish "gossan." The iron oxide is really the result of the decomposition ot iron pyrites; and in the lode with this at "grass roots/' iron pyrites would be found deeper down. Having thus traced the honeycombed quartz the pieces of which are 8 THE PROSPECTOR'S HANDBOOK. less angular and smoother the farther away they lie from the lode or other likely matrix rocks up the hill or mountain side to some, outcropping rock (often forming a distinct ridge) from which it has been hurled down, or to where the detached pieces cease to be noticed, the prospector may dig a trench at right angles, if possible, to the lode, in order to examine its character, the nature of the vein and the gangue, and to find the bounding walls, viz. the upper or hanging wall, and the lower or foot-wall, as well as to note the direction or " strike 7 ' of the lode; he must notwith- standing, for the sake of accuracy, " sink " a " prospecting shaft " a few feet deeper than the bottom of the trench, as the inclination of the lode near the surface is most mislead- ing, on account of the body of ore having been distorted from its original shape. When once the probable direction of the lode is ascertained, the positions where it is desirable that other pits, lower down or higher up the hill or on the other side of a valley, should be sunk so as to test the continuity of the vein, are settled. Should the prospect of the vein being a continuous one seem favourable, and the surface " assays " turn out well, development of the claim may be attended to. At the same time, no person should be led away by such a hope as that "the deeper the vein the more payable the ore " ; for, as a fact, though certain lead and copper veins do improve by depth, and also very many gold-bearing lodes for instance, those in Grass Valley, California, which seem to be as rich at 1,000 feet deep as at the surface very many do deteriorate in value; nor is it prudent to attach too much affection on any particular lode, until the surrounding country has in some measure been examined. Besides, it is now a recognised fact that veins vary in quality and nature according to the strata they pass through. Even if the prospects look bright, a person who goes in for mining ought not to be too sanguine of success, for mineral veins are most apt to disappoint ; frequently do they "pinch out" between hard rocks, or end in a "pocket," or become changed in character and value when least oxpected. To err on the safe side, it is just as well for a happy possessor to make sure that at least the surface rock VALUE OF A MINING CLAIM. " assays " payably, simply because his money and time are of too much worth to admit of the expensive and sometimes apparently endless labour involved in developing work. A capitalist may risk some of his quickly amassed gains in following up research in the hope of some day increasing his capital, although he quite understands how thoroughly the game is a chance one ; but the ordinary miner should avoid uncertainties much more than he usually does. That a lode carries gold and silver or any other valuable metal in some form or other, is not sufficient data to lean upon in the estimation of its worth. Oftentimes the gold, for instance, is distributed in the form of very fine powder invisible to the eye and covered with a rusty film (due to sulphides or arsenides, oxide of iron or manganese, and sometimes to sulphate of copper and iron) ; and in conse- quence, though the " assay " may be favourable, the extrac- tion of the precious metal from the ore by the amalgama- tion is not satisfactory, as the mercury " sickens " or " flours." Again, the value of a body of ore, though it may be rich in precious or valuable metals, depends in a measure upon the nature of the other constituents, especially when the ore has to be smelted. Antimony or arsenic, in not very great quantities either, may render an otherwise valuable ore useless so far as profitable smelting is concerned. Before digging operations are commenced, the pieces of rock from the lode should be examined, and, if such is possible, by a reliable assayer, who, if he suspects the presence of precious metals, will, by scorification or melting in a crucible, and afterwards by cupellation method, determine the amount of gold and silver per ton of a similar rock, and, without undertaking a careful quantitative analysis of the other associated metallic compounds, will, from the slag in the scorifier or crucible and colour or appearance of the bone ash cupel after the operation is concluded, be able to judge approximately what proportions of the metals copper, iron, lead, antimony, zinc, &c., are mixed with the others. It is always the wisest plan to obtain a proper assay before development work is entered on. Unfortunately, this is not an easy matter in out-of-the-way places. To assay correctly means a course of training ; for this reason the author can- io THE PROSPECTOR'S HANDBOOK. not conscientiously advise anyone to undertake a silver or gold assay by scorification and cupellation, nor a " burette " one for copper, iron, zinc, &c., until he has practised the methods under the eye of an assayer ; because in all likeli- hood his own attempts, though they might be near the mark as to results, would more than probably be quite mis- leading. Still, there is no reason why an inexperienced person should not attempt to qualitatively test minerals by simple methods, nor in some instances do so quantitatively. To fly to the assistance of a chemist or a mineralogist or an assayer for every little matter of inquiry concerning minerals is not only inconvenient, but in many mining districts unsatisfactory, as there are, naturally, so many unreliable so-called authorities to be met with. Because a miner pro- nounces such a mineral unlike anything he has seen in Cornwall, or California, or Ballarat, and devoid of anj valuable metal, the prospector need not be too ready in accepting such an opinion ; for, as a rule, the knowledge of an ordinary miner, expert, perhaps, in certain matters, such as timbering tunnels, &c., is neither remarkably extensive nor always sound. Neither must he depend on the super- ficial conclusions of any professed expert who has arrived at such by a superficial examination, even with the help of a magnifying glass. Experience abroad tells one that not only has the ordinary miner erroneous notions about such minerals as grey copper ore, silver glance, fine and coarse- grained galena, &c., but also that the most experienced mineralogist cannot for a certainty tell at first sight how much gold or silver may be concealed in a particular rock. Both of these precious metals are found in several places, which many persons might call most unlikely formations, and it is quite a common thing to handle specimen rocks worth- less in appearance and yet assaying very high in gold and silver, and also handsome, looking specimens that disappoint in not "running" anything to the ton in either of the precious metals. Nor can a person, unless he be a thorough expert, depend upon the appearance of certain pieces of ore for a guide as to the yield of valuable metals. Many of the silicates, carbonates, and chlorides are perfectly unmetallic to look at, and when associated with other metals are very DIFFICULTY IN DETECTING MINERALS. n deceiving as to their real value. For a long time the chloride of silver deposits in Colorado were passed over without their nature being known, and so were the car- bonate of lead (carrying silver) unnoticed at Leadville, which, through the discovery, in five years became a city of 30,000 inhabitants. Who would say how much per cent, of nickel there is in a particular piece of the New Caledonia hydrated silicate of nickel ore, or how much silver in the Leadville ore, or what proportion of gold is likely to be in a lump of copper pyrites or iron pyrites, unless he had made each a special study ? Therefore it is just as well that a person should be independent of the opinions of others and, to a certain extent, of his own ; and, at the same time, never grudge a few shillings or dollars in obtaining the advice of a proper assayer. Let us now return to the original subject. Supposing that a correct assay of the lode matter has been secured or a rough one made, the prospector has still some items of significant worth to consider before he commences to build " castles in the air," or even continue development work. He must find out if the ground is easily worked (for in one locality though " sinking " through a soft ground may only cost 2 a fathom, " sinking " through hard ground may cost 20 or more) ; if the ore to be smelted is refractory, or is capable of concentration after sorting, before it is sent away to the smelting or to the crushing and amalgamating works. He must find out exactly the price of smelting or otherwise treating the ore, taking into consideration such items as the cost of labour, the freight of ore and fluxes as well as their cost, the freight of the ores to the " works," &c. He must take into account the proximity or distance off of both fuel and water, as well as the obtainable quantity of each. Many spots in Arizona and New Mexico exist where the working of veins and alluvial diggings is impossible for the time present, or retarded through the absence of creeks and springs. He must remember that a lode running twenty dollars' worth of metals to the ton may be of more value than another running two hundred dollars not very many miles off ; that a low-grade silver ore in one locality may be THE PROSPECTOR'S HANDBOOK. of more intrinsic worth than a vein of pure silver, having the thickness of a knife blade, in another. In brief, the character and quality of ore, as well as the probability of the continuity of the lode, the location of the mining claim, the number of acres of available fuel and timber within reach, the proximity and quantity of water, every expense attendant on carriage, smelting operations, &c., should be considered in detail before the development of any single mine merits commencement, in order to turn out a profitable concern. It has been said that in the world there are ten unprofitable mines to one profitable ; so let no one take the trouble to dive into the above considerations until he really believes that there is " payable stuff" to be dug out of his " claim " ; let him avoid the habit of reckon- ing the value of a property from a few picked specimens. CHAPTER II. ROCKS. Rocks classified. Superposition of stratified rocks. Lamination. Stratification . Denudation. Cleavage. Joints . The condition under which metal-bearing deposits are found. Nature of mineral veins in a lode, &c. Dip. Strike. Clinometer. Compass. THE following are the various divisions under which rocks may be classified : IGNEOUS. (Rocks which have been subjected to heat.) Volcanic (those that have been cooled at or near the surface) : Trachyte (rough, greyish in colour, and light in weight). Basalt (blackish or brown, heavier and with fewer holes in it than trachyte). Phonolite, Andesite (of which porphyrite is an altered variety). Dolerite (with crystals more promi- nent than in basalt) : elvans (including quartz-porphyry) : pitchstone, &c. These last three occur as dykes or intru- sive sheets : the two last are offshoots of granite formations. Obsidian (usually transparent and like bottle glass, pumice, &c.) : rhyolite, &c. Plutonic (those that have cooled at some depth below the sur- face) : Granite, porphyry, syenite, diorite, gabbro, &c. ; these usually have a distinctly crystalline structure, frequently with large crystals. MET AM ORPHIC. (Of igneous and aqueous origin, but which have undergone a change by pressure, &c.) Gneiss (in composition like granite, but foliated). Mica schist (quartz and mica), hornblende schist, talc schist, chlo- rite schist, diorite schist, are some of the foliated forms. Quartzite and some serpentines are metamorphic. AQUEOUS. (Deposited by liquid agency.) Gravel (made up of loose rounded pebbles), conglomerates and breccias. Grit (in which the grains, usually of quartz, are cemented together). Sandstone (in which quartz grains are very fine). THE PROSPECTOR'S HANDBOOK. Sand (in which the grains are loose). Clay (silicate of alumina and of a plastic nature) . Slates (hardened clay, which displays cleavage across the bedding). Shales (hardened laminated g^ ^ o o 60 o ^ 'O ^ ^>-l 'o 'O 0^ S Q 3 Q Q .2 1 3D Q 02 02 02 3 ' O a i * J i N i ii* 1 1 1 O ^j " | I t-i O H Q -8 00 / M Q M"" ~ - ^- - i i & i s i s M B ' 3 ' * 3o ^ ^00 ^v SM -S^/"^l 1 1 ) (^( C/^CICSJ OQ Q 1 2 .rj ^H S ' >^gS "^ >^>% ^T3^i JH 6 ^S^ pQ ) 55 5r^5 6D .3 6 1 1 "o jj fl w J5 5 5 r2 5 OH ~- O o s Q 1 1 ^ |^ 1 -3d 111 03 ^ s *o p,3 do ^o d^do f^ ^ & 60 o rSWS^fi 1 ^^ 3 r2 C3 i^ ^O ^O ( O 1 6 o-S 6 666 In Oxid ! 1 i i IN 1 I III METHODS OF TESTING. 29 Moisten the loop, and dip it into either borax or * micro- cosmic salt ; then heat it in the blowpipe flame till the flux is fused. When the head is soft or moist, it must he brought in contact with a very small quantity of the powdered mi- neral, and then exposed to the heat of the oxidizing flame, and afterwards to that of the reducing flame, the change of colour of the head when hot or cold, and the effect of each flame on it, being carefully observed. If the substance, after heating, be moistened with nitrate of cobalt solution, and again strongly heated, it may when cool afford some clue to its nature (see Table C). This reagent is often used for detecting ( magnesia, which gives a pale red colour ; \ alumina, blue without lustre. GENERAL TABLE C. (For the Analysis of Metallic Substances.) 1. Heat the substance in a tube closed at one end : Sublimate : white = mercurous chloride, white antimony, &c. ,, greyish black = mercury, &c. black, red, on rubbing = cinnabar (sulphide of mercury). black when hot ; red, cold = antimony sulphide. Arsenical minerals, too, afford a sublimate. 2. In open tube : Sublimate : metallic globules = mercury. ,, white fumes = antimony. 3. Alone on charcoal : Colour of outer flame : green = copper, &c. blue = lead, chloride of copper, &c. (i.) Metals reduced without incrustation : White, malleable bright bead = silver. Yellow = gold. Red metal = copper. Grey powder = iron, cobalt, nickel, platinum, (ii.) Metals reduced with incrustation : Incrustations : lemon yellow when hot ) , ^ \ sulphur yellow when cold ( ~~ /malleable yellowish when hot | ( metal, white when cold ) ~ tm< ) orange, when hot \ = bis- \ lemon yellow when cold j muth. /brittle wiiite (fumes given off } = anti- i metal. on withdrawal of flame) j mony. / * N.B. Microcosrnic salt is inclined to froth up and fall off the wire ; BO only a very small quantity must be taken up at once. 30 THE PROSPECTOR'S HANDBOOK. Incrustation without reduced metal : yellow when hot ) . . white when cold j = 4. On charcoal, with carbonate of soda : Same as in 3. 5. On platinum wire with borax : Consult Table A. 6. On platinum wire with microsmic salt: Consult Table B. 7. Heated on platinum wire moistened with hydrochloric acid : Flame colour: blue copper (afterwards green), lead, anti. mony, arsenic, selenium ; green = copper, also molybdenum, barium, phosphorus, &c. 8. On charcoal with nitrate of cobalt solution : Green mass = oxides of zinc, antimony, tin, &c., &c. Confirmatory tests when the mineral has been treated alone on charcoal or with carbonate of soda : (i.) When metallic beads or spangles are left : Silver. If dissolved in nitric acid, an addition of hydro- chloric acid or a solution of common salt will precipitate white chloride of silver. Gold. If dissolved in 4 parts hydrochloric acid and 1 part nitric acid, a precipitate of purple of Cassius will be obtained when protochloride of tin is added. Copper. If treated with borax on platinum wire it will give reactions, as in Table A. (ii.) When a grey or blackish residue is left : Heat the residue with borax on platinum wire and note the colour of the bead; compare results with Table A, for COBALT, COPPER, IRON, NICKEL. (iii.) When the mineral yields an incrustation on the charcoal : Antimony. If the scraped-off incrustation be treated with hydrochloric acid and zinc on a piece of platinum foil, a black film of antimony is formed. Lead. If dissolved in nitric acid, the excess of acid evaporated and a little sulphuric acid be added, a white powder will be formed. Tin. If dissolved in hydrochloric acid, a grey precipitate is formed when metallic zinc is placed in the solution. CONFIRMATORY TESTS. 31 Zinc. If the incrustation be heated with the nitrate of cobalt solution, it becomes green. To detect certain common substances associated with metals : Alumina. This is known by its adhering readily to the tongue when licked. Tested before the blowpipe with nitrate of cobalt; it becomes blue. Lime. This gives a very bright light when heated before the blowpipe flame. It is infusible even with carbonate of soda, and so differs from silica and flinty substances. Carbonate of Lime effervesces when a little hydrochloric or citric acid is dropped on it. Magnesia. When heated with nitrate of cobalt solution, becomes flesh red. ( Soda. When strongly heated, gives a reddish yellow < colour to the outer flame. ( Potash gives a violet colour to it. Sulphur is known by its characteristic odour when the substance is roasted. If a portion of the heated mineral be placed on a moistened piece of silver, a black stain shows the presence of sulphur. Arsenic is known by its characteristic garlic odour when heated. All carbonates effervesce in acids. * (N.B. A limestone rock, which is made up of carbonate of lime, can thus be easily distinguished from a sandstone, &c.) Certain silicates, when acted on by acid and heated, gelatinize. N.B. A blowpipe for temporary use may be made thus : Procure a long pipe of glass tube (J inch thick). Hold it horizontally over the flame of a spirit lamp. As the middle part becomes softened pull both ends of the tube horizontally, until the middle part of the tube is about the thickness of an ordinary blowpipe jet. File a notch on the thin part, and snap the tube. Now take one portion and again heat it (a little distance from the nozzle), and bend it so that the nozzle may be inclined at an angle to the longer branch. * Citric acid, which can be conveniently carried about as crystals and dissolved in a little cold water, is a most useful re-agent. Nearly eveiy carbonate can be dissolved with effervescence in a cold solution. Spathic iron requires a boiling solution. CHAPTER IV. THE CHARACTER OF MINERALS. External Characteristics. Tables for determination of the nature of a Mineral by noting its Colour, Lustre, and Streak. Specific Gravity. Hardness. Crystallization. IN order to discover the nature of a rock, the mineralogist may derive the necessary information by a careful study of its external appearance and characteristics ; the form of crystallization, hardness, specific gravity, colour, streak (the colour when scratched, or when rubbed on a piece of porce- lain), &c., and also from its behaviour when exposed to the action of chemicals or heat. When examining a mineral specimen, the prospector is, to a great extent, guided by its colour. He may form a truer estimate by also noticing the lustre and streak. But it must be borne in mind that, for example, tinstone, though usually found of a brownish or blackish colour, is sometimes grey. Its streak, too, is not always brown, but sometimes grey, &c. Cinnabar, too, is usually red, though occasionally brown or brownish-black. The following table may be of some use in the examina- tion of some of the most commercially useful minerals : METALS WITH METALLIC STREAK. COLOUR. STREAK. Gold Yellow . Yellow. Silver White (inclined to tarnish) . White. Copper Red . Red. Platinum . Bismuth . Grey Silver white (slightly Grey. red tinge and in- clined to tarnish) . Silver white. TO DETECT MINERALS BY THEIR COLOUR, ETC. 33 Also mercury, palladium, osmium, iridium, lead, antimony, tellu- rium, &c. Graphite has a dark steel grey metallic lustre and black metallic streak. MINERALS OF METALLIC LUSTRE. COLOUR. STREAK. Yellow Copper pyrites . Brass yellow (some- times tarnished) Greenish black. Iron pyrites Yellow . Brownish black Magnetic pyrites Between copper red and yellow Greyish black. White Arsenic pyrites Silver white . Greyish black. * Nickel glance . Silver white or steel grey . Greyish black. Bed Kupfernickel . Copper red (grey- ish or black when tarnished) . Pale red. Arsenical nickel Pale copper red Pale brown-red. Brown Brown haematite Brown . Brown and yellow. Chromic iron . Brownish black Dark brown. Grey or Black Specular iron . Dark steel grey Dark cherry red. Magnetic iron . Dark iron grey Black *G-alena . . Lead grey Lead grey. Antimony sulphide . Lead grey Lead grey and black- ish. *Grey copper . Grey and black Steel grey ; black, sometimes brownish Bellmetal ore . Steel grey . . 1 Blackish. * Copper glance . Cobalt, tinwhite Black grey . Tinwhite, grey Blackish lead grey. Greyish black. Frank Unite Dark black . Dark brown. Earthy cobalt . . I Black or blue black Blackish. * Brittle silver . . Black or iron grey Black or iron grey. ' : Silver glance . Black or grey Blackish or iron- Black oxide of man- grey. ganese . . . Iron black . Black. Sulphide of molybde- | num . . . Grey, like graphite Grey. Also several lead and antimony compounds, tellurides, &c. Certain micaceous iron minerals, which giro a red streak, are some- what metallic-like in appearance. * The streak has a metallic lustre. 34 THE PROSPECTOR'S HANDBOOK. MINERALS OF UNMETALLIC LUSTRE. COLOUR. STREAK. Yellowish-Brown Brown iron ore . . . . . . . Yellowish. Molybdenum ochre, oxides of lead, antimony, bismuth, carbonate of bismuth, &c. have sometimes a yellow tinge. White Silicate of zinc . Whitish (sometimes other colours) . Whitish. Carbonate of lead . White or bluish . Colourless. Horn silver . . Greenish white, pearl grey, &c. . Grey and shining. Chloride of mercury , Dirty white or grey - 1 ish . Yellowish. Sulphate of lead, carbonate of lime, clay, &c. Bed Cinnabar . . , Red . Red. Ruby silver Cochineal . . Crimson red. Red zinc ore . Bright red . Orange yellow. Cobalt bloom . Peach red . . Paler ; lavender. Red copper ore Red (sometimes iron grey on sur- face) Brownish red. Minerals with silicate or carbonate of manganese in them are sometimes pinkish. Brown Calamine . . - . Brownish '. ' . Whitish. Tinstone . Brown . Brownish. Zinc blende Brown, brownish - red or blackish . White to reddish brown. Spathic iron . Brownish red. . j Uncoloured. Some varieties of brown iron ore Brownish . . 1 Yellowish. Some varieties of specular iron ore . Brownish Red. Black Black oxide of copper Black . . . Black. Black oxide of man- ganese (submetallic) Ruby silver . ( . Black . . . Black. Reddish black . Crimson red. Tinstone . Black . . . Brownish. Zinc blende Blackish Various. TO DETECT MINERALS BY THEIR COLOUR, ETC. 35 MINERALS OF UNMETALLIC LUSTRE. Continued. COLOUR. Green Malachite . . i Emerald green Pyromorphite . . 1 Greenish STREAK. Light green. White or Yellow. Also emerald ickel, silicate of nickel, and silicate of _ Also certain chromium and uranium compounds, certain phosphates and chlorides, arseiiate of copper, chloride of copper, silicates of magnesia, &c., on surface nickel ore, green stains may be noticed. Many other minerals, such as silicate of magnesia, have a greenish tinge, also phosphate and chloride of lead, sulphate of copper, and certain phosphates, &c. Blue Malachite and azurite Blue Bluish. The specific gravity of a rock can often be approximately known by weighing it in the hand, and comparing it with an equal bulk of some other familiar rock ; but to accurately obtain the specific gravity of a mineral, a fragment of it should first be weighed in air, then in water (which can be done by suspending it to the scale of a balance and im- mersing it in water). The weight in air, divided by the weight in air minus the weight in water, gives the specific q p __ weight in air gravi y. . we jg n t j n a j r W eight in water. But this method is more for the scientist than the ordinary prospector. The colour and appearance of the line or furrow on the surface of a mineral, when scratched or rubbed, is called the streak, which is best obtained by means of a hard tempered knife or a file. If the mineral is soft, it may be rubbed on a piece of rough porcelain. Those parts which have been much weathered should not be chosen. To discover the hardness of a mineral, it is necessary to try and find out which of the typical specimens of the scale of hardness (commencing with the hardest and proceeding to the lowest) is scratched by it. THE PROSPECTOR'S HANDBOOK. SCALE. 1. Talc (such as soaps tone), easily scratched by the finger nail. 2. Rock salt (also gypsum, zinc, &c.), not easily scratched by the nail, nor can scratch a copper coin. 3. Calc spar (transparent), both scratches and can be scratched by a copper coin. 4. Fluor spar, not scratched by a copper coin and does not scratch glass. 5. Apatite, with difficulty scratches glass and is easily scratched by a knife. 6. Felspar, scratches glass and is not easily scratched by a knife. 7. Quartz, not scratched by a knife and easily scratches glass. 8. Topaz, harder than flint. 9. Corundum, oriental emerald, sapphire, &c. 10. Diamond, scratches any substance. The hardness of minerals that can be scratched by the finger nail is 2J or less, and by a copper coin less than 4. Minerals may often be recognised, or their nature verified, by the crystallization they assume. The following are the fundamental forms of ciystals : 1. Regular system (called the cubic, octahedral, &c.). In this system there are three equal axes (imaginary) pass- ing through the same point and at right angles to each other. For examples CUBE. OCTAHEDRON. TETRAHEDRON. RHOMBIC DODECAHEDRON FIG. 24. FIG. 25. FIG. 27. 2. Square prismatic system (has three axes at right angles to one another of which two are of equal length). FORMS OF CRYSTALLIZATION. 37 Examples EIGHT SQUARE PKISM. BIGHT SQUARE -BASED OCTAHEDRON. FIG. 28. FIG. 29. Fro. 30. 3. Eight prismatic system (right rhomhoidal or rectan- gular prismatic system), in which the three axes are of un- equal length, though at right angles. 4. Oblique prismatic system, which includes the right rhomboidal prism and the oblique rhombic prism. The three axes may be of unequal length while two are at right angles, and the vertical axis inclined to one of these. ExampleFig. 30. 5. Double oblique prismatic system in which three axes are unequal, and not any at right angles. 6. Ehombohedral system (regular hexagonal system). There are four axes, three of which are in the same plane and inclined to one another at an angle of 60, the other being vertical : frequently the prism is capped by a six-sided pyramid. Example Fig. 31. Various names are given to the above systems, viz. : 1. Cubic, regular system, monometric. 2. Square prismatic, tetragonal, quadratic, dimetric. 3. Eight prismatic, rhombic, trimetric. 4. Monoclinic. 5. Triclinic or anorthic. 6. Ehombohedral. Crystalline form is not always sufficient evidence to rely upon in the determination of a mineral, as several different FIG. 31. 38 THE PROSPECTOR'S HANDBOOK. minerals assume the same or nearly the same shapes of crystal ; and, again, certain particular minerals are found of more than one shape. As examples of the first are carbonates of lime, lime and magnesia, zinc, iron, where the angle of the rhombohedral forms only vary between 105 and 108. Sulphur, iron pyrites, specular iron, carbon, are examples of the second kind. In addition to the already-mentioned characteristics use- ful in the determination of the nature of a particular mineral, some peculiar properties belonging to certain minerals should be noted. For instance, some iron, cobalt, and nickel ores are attracted by the magnet ; some minerals such as fluor-spar, topaz, carbonate of lead, quartz, and calc spar become electrified by friction ; others such as calami ne become so when heated. Others, when rubbed, yield a peculiar odour ; some such as fluor-spar are phosphorescent, that is, yield a peculiar light when heated ; while many possess a characteristic taste. CHAPTER V METALS AND METALLIC ORES: THEIR CUARAG- TERISTICS. TESTING. OCCURRENCE, $e. General remarks. Aluminium; beauxite; cryolite. Antimony; sul phide. Bismuth. Chromium ; oxide. Cobalt ; tin white ; earthy oxide. Copper ; native ; glance ; pyrites ; grey ; ruby ; black oxide ; silicate ; malachite. Gold ; detection of and distin- guishing tests ; peculiarities ; panning out ; mechanical assay ; sluicing ; native gold, &c. Iron ; pyrites ; magnetic pyrites ; arsenical pyrites ; haematite ; magnetic iron ore ; brown iron ore ; franklinite ; vivianite ; copperas ; spathic ore. Lead ; galena ; carbonate ; pyromorphite ; chromate ; sulphate ; rough method for obtaining lead from galena. Manganese ; black oxide, wad, &c. Mercury ; native ; cinnabar ; chloride ; selenide ; to obtain metal from ore. Nickel; kupf ernickel ; white; emerald; hydrated silicate. Platinum ; native. Silver ; native ; brittle ore ; glance ; horn silver ; ruby ore ; silver in carbonate of lead. Tin ; tinstone ; bellmetal ore. Zinc ; calamine ; silicate ; red zinc ore. As mentioned before, in the last chapter, any one who searches for useful minerals is chiefly attracted by their colour ; the lustre, and perhaps streak, may assist him in the determination of their nature. Still, doubts may suggest further investigation. The hardness and the specific gravity may guide him, though it must be confessed, in the case of small minerals, it is no easy matter to accurately find out the latter. Even then recourse may have to be had to what in many cases is really the most satisfactory way of solving the question, namely, to tests by means of the blowpipe or by chemicals. In the following pages is given an account of the principal useful ores comparatively few in number including a description of their characteristics and behavi- our in the blowpipe flames and with certain chemicals, also of the country rock in which the lodes or deposits occur. As a general rule, the ordinary prospector concentrates his attention to the discovery of the precious metals, gold 40 THE PROSPECTOR'S HANDBOOK. and silver (usually the former). Perhaps he keeps a look- out for lead and copper ores, but very seldom (even when in a granite country) thinks about searching the streams for tinstone or the hills for tin-bearing lodes. He may pass by, or even handle and throw aside, such unmetallic-like minerals as some of the silicates, carbonates, chlorides, &c., simply because of their lightness of weight, or because they do not come up to his notions about what a metal-bearing rock should be. He may even discard some of the heavy mine- rals on account of their nature being disguised by the pre- sence of iron oxide, which may give them the appearance of an iron ore. Hence the desirability of examining carefully all sorts of minerals and submitting them to tests. Although in this chapter many of the different metallic compounds are described, it would be well if the prospector made himself especially well acquainted with the appearance of the various oxides, and in a lesser degree with the car- bonates, chlorides, &c. The sulphides which are found deep down a lode become chiefly converted to oxides on the sur- face. Take, for instance, a lode in which copper pyrites and iron pyrites exist several fathoms down. On the out- crop there would probably be the rusty colour due to iron oxide ; and black oxide (perhaps the red) of copper, and also the green or bluish stain of carbonate of copper might be distinctly noticed. Still, whether the prospector comes across oxides, carbonates, chlorides, sulphides, or metal in the native state, recourse to the following pages may, per- chance, help him to solve the question as to what the true nature of the particular mineral is. ALUMINIUM. This metal is not found in the native state, but in combi- nation with silica, oxygen, fluorine, &c. Corundum, sapphire, and ruby are nearly pure alumina (oxide of aluminium). Emery is a more impure variety. The silicate is very abundant and is a constituent of the older rocks, of all clays, &c. The presence of alumina is known by heating the substance in the B.F., then moisten- ing it with nitrate of cobalt solution and again heating. A blue, lustreless colour will indicate the presence of alumina, ANTIMONY. 41 thus distinguishing it from magnesia in a mineral (see p. 29). The principal ores besides corundum (H. 9), found in great quantity in crystalline rocks in America, and from which aluminium is extracted, are Beauxite. Of various colours. Sometimes made up of concretionary grains. Also as clay (sometimes coloured by iron oxide). S.G. 2-55. Contains sometimes more than 50 per cent, of alumina (or more than one-third aluminium), the rest being sesqui- oxide of iron, silica (in small quantity), and water. Is soluble in sulphuric acid. Cryolite. A semi-transparent, brittle mineral. Colour whitish yellow, reddish, or black. H. 2-5 ; S.G. 3. Is a double fluoride of aluminium and sodium, and con- tains sometimes 13 per cent, of aluminium. Easily fusible in candle flame. Beauxite is chiefly found near Aries, in the south of France. A rather similar clay has been found in Ireland. Cryolite is obtained in Greenland (in gneiss), also in America. Aluminium is of a white colour, easily polished, adapted for casting into moulds, does not become tarnished on ex- posure to the atmosphere, and hence is suitable for very many purposes. ANTIMONY. The metal is usually found combined with sulphur, arsenic, or sulphur and lead. If a mineral be supposed to contain antimony in any form, the presence of the metal may be known by treating the specimen with carbonate of soda on charcoal in the K.F.* of the blowpipe, when, if it * (N.B.O.F. =z Oxidizing Flame; R.F. Reducing Flame ; B.F. =: Tttowgipe Flame ; S.6r.-=. Specific Gravity ; JET. = Hardness.} 42 THE PROSPECTOR'S HANDBOOK. be present, a bluish white incrustation is formed, which (being volatile) disappears when exposed to the O.F. and R.F. ; in the latter case with green coloration. The bead is white and brittle. To confirm : Scrape the incrustation off and treat with hydrochloric acid and zinc on platinum foil. A film of antimony will be left on the latter. If a piece of ore containing antimony be heated in an iron spoon, white fumes will rise and coat the rim. The behaviour of anti- mony with borax or platinum wire before the blowpipe flames is, when cold, in O.F. = colourless, in E.F. = colourless to grey. Combined with lead, or bismuth, or copper, other tests have to be resorted to. Antimony is a most undesirable metal to be associated with other metallic compounds in a vein, as it interferes with the ordinary smelting processes. Sulphide of Antimony (grey antimony). The ore from which the antimony of commerce is ex tructed Crystallization right rhombic prisms. Colour lead grey. Streak lead grey and blackish* Lustre shining and metallic. Structure brittle : thin laminse slightly flexible. EL 2 ; S.G. 4-5 to 47. Composition per cent. antimony, 73; sulphur, 27. Fuses in the flame of a candle. Before B. flame and on charcoal yields white fumes with odour of sulphur. When pure, is soluble in hydrochloric acid. The oxide yellow, white, grey, or brown is sometimes found on the outcrop of a sulphide-bearing lode. Can be distinguished from an ore of manganese, like in appearance, by its being easily fused and its diagonal cleavage. There are about ten varieties of this last ore, the streaks of which vary ; all the ores, however, are soft, and can be scratched by the finger nail. Grey antimony occurs with ores of silver, lead, zinc, or iron, &c., and is often associated with heavy spar and quartz. Found in metamorphic and COBALT ORES. 43 igneous rocks. If antimony sulphide is heated in a glass tube closed at one end, a sublimate, black when hot, red- dish-brown when cold, is formed near the test-piece. BISMUTH. Found chiefly in the native state, but also in combina- tion with sulphur, oxygen, tellurium, carbonic acid, &c. It yields a yellow incrustation in the O.F. of the blowpipe. The oxide, sulphide, arsenide, combined sometimes with copper, lead, &c., vary in colour, hardness, and specific gravity. Bismuth glance, containing 81 per cent, of the metal, is usually of a lead-grey colour. When heated in a closed tube yields a sulphur sublimate. On charcoal before the B.F. sputters and deposits a yellow incrustation leaving metallic bismuth. Oxide and carbonate of bismuth (gene- rally of a yellowish, though sometimes grey, greenish white, &c.) is often found at the surface of a bismuth-bearing lode. In Wales and elsewhere bismuth sulphide is sometimes found in gold-bearing ore, as at the St. David's mine. CHROMIUM. The oxide is chiefly found with iron, as chrome iron. Colour brownish black. Lustre submetallic . H. 5-5 ; S.G. 4-5. Before the B.F. yields a green bead with borax. Chromate of lead is rarely found. Occasionally an emerald green incrustation is found on chrome iron ore. Chrome ochre is of a yellowish green colour. Chrome iron is frequently found in a serpentine-rock country. Chromium compounds are often associated with nickel and cobalt ores. COBALT. Compounds of cobalt, when heated on charcoal before the B.F., yield whitish metallic spangles, which can be attracted by a magnet. The metal moistened on paper with nitric acid gives a red solution, which with hydro- chloric acid affords a green stain on drying. Treated with borax in either B.F. it yields a deep blue bead. Before testing, metallic compounds should be roasted, to drive off volatile matter. 44 THE PROSPECTOR'S HANDBOOK. Tin White Cobalt, Crystallization octahedral, cubical, and dodecahe- dral, &c. Breaks with uneven and granular fracture. Colour tin white and greyish. Streak greyish black. H. 5-3; S.G. 6-4 to 7-2. Composition cobalt and arsenic. Before the blowpipe it colours borax and other fluxes blue. Affords pink solution with nitric acid. Earthy Oxide. Usually massive. Colour blue black or black. H. 1 to 1-5; S.G. 2-2 to 2*6. Composition oxides of cobalt and manganese, Cobalt Bloom. Lustre pearly. Colour peach red, crimson ; sometimes grej" or greenish. Streak paler ; powder-lavender. Composition per cent. oxide of cobalt, 37*6; the remainder, arsenic and water. Gives off arsenical odour when heated. Behaviour with fluxes in the B.F. same as other cobalt ores. In Great Britain cobalt ore is found in cavities in lime- stone of the carboniferous age. In Norway and other countries a variety of tin white cobalt is found in gneissic and primitive rocks. In Germany deposits of cobalt are found in limestone over copper slates. Cobalt and nickel ores are often met with in the same lode. COPPER. If a specimen is supposed to contain copper, it should be examined either by means of the blowpipe or chemicals. With carbonate of soda on charcoal before the B.F., nearly any copper ore is reduced and a globule of metallic copper obtained. Heated with borax or microcosmic salt in O.F., there results a green bead when hot, a blue one wlnn cold. Most copper compounds, when heated in the im er flame, COPPER ORES. 45 impart a green colour to the outer one. Copper compounds are, for the most part, soluble in nitric acid. If a piece of polished iron or the bright point of a penknife be dipped into the acid solution, it will be slightly coated with metallic copper if any exist in the ore. Ammonia added to an acid solution affords a green colour, and, in excess, a blue one. Many copper minerals can be dissolved in citric acid, some in cold, others in a boiling solution, and afford a greenish colour. A penknife blade (clean; placed in the solution is covered with a copper film. Some, such as copper pyrites, may be dissolved in a boiling solution of citric acid and nitrate of soda. In the absence of a blowpipe or chemical apparatus, the presence of copper in a substance may be detected in this way : First, roast the mineral and drop it, when hot, into some grease and expose it to the heat of a flame, which will show a green colour if copper exists. Or, if the mineral be well powdered, mixed with some fat and salt, and placed in the fire, the presence of copper will be known by the blue or green colour. If the powdered mineral be mixed with a little charcoal and roasted for an hour, and then vinegar be poured on it and allowed to remain for a day or so, copper will produce a blue colour, afterwards becoming green. In a copper-bearing lode the black oxide, sometimes red oxide and green carbonate, may be noticed in the cavities of the surface quartz. Native Copper. Found in treelike, mosslike, threadlike shapes, in octahe- dral crystals, grains, &c. Colour copper red. Is ductile and malleable. H. 2-5 to 3 ; S.G. 8-5 to 8-9. Can be tested by the blowpipe or chemicals like other copper ores. Usually carries silver. Found chiefly in North and South America, also in Cornwall, Wales, &e. Copper Glance (vitreous copper ore). Crystallization rhombic prisms. Is slightly sectile. Colour blackish grey, tarnishing to blue or green. 46 THE PROSPECTOR'S HANDBOOK. Streak blackish grey, sometimes shining. H. 2-5 to 3 ; S.G. 55 to 5-8. Composition per cent. sulphur, 2O6 ; copper, 77 -2: iron, 1*5. Before the blowpipe gives off sulphur fumes, fuses easily in the outer flame, and boils, leaving a globule of copper. Is fusible in a candle flame. Is rather like sulphide of silver, but the button left after exposure to B.F. shows the differ- ence. If the mineral be dissolved in nitric acid, and the point of a penknife be placed in it, a slight copper coating will be formed if the metal is present, whereas, if a piece of bright copper be placed in it, a slight coating of silver will be formed if silver be present. Copper Pyrites (chalcopyrite). Crystallization tetrahedral, also massive, &c. Colour brass yellow, sometimes tarnished and iri- descent. Streak greenish black and unmetallic. H._ 3-5 to 4 ; S.G. 4-15. Composition per cent. sulphur, 34'9 ; copper, 34'6 ; iron, 30'5. In a glass tube closed at one end it decrepitates, and a sulphur sublimate is left. Before the B.F., it fuses to a metallic globule. If fused with borax, metallic copper is the result. Tested in acid, like other copper ores. Is sometimes mistaken for gold, iron pyrites, or tin pyrites; but it crumbles when cut, whereas gold can be cut in slices. Is of a deeper colour than iron pyrites, and yields easily to the knife, nor does it strike fire like iron pyrites. It may be distinguished from tin pyrites by the blowpipe and other tests. If the ore be hard and of a pale yellow colour, it is considered to bo poor in copper. Variegated copper pyrites (containing 60 per cent, of copper) is of a pale reddish yellow colour. G-rey Copper (tetrahedrite). When containing silver, Fahlerz. Crystallization tetrahedral, &c. COPPER ORES. 47 Structure brittle. Colour between steel grey and iron black, sometimes brownish. Streak between steel grey and iron black, sometimes brownish. H. 3 to 4; S.G. 4-75 to 5-1. Composition per cent. copper, 38 '6 ; sulphur, 26*3 ; antimony and arsenic, zinc, iron, silver, &c. It sometimes contains 30 per cent, of silver in place of part of the copper. After roasting, yields a globule of copper before the B.F. When powdered and dissolved in nitric acid, the solution is brownish green. The ore can be distinguished from any silver ore by the blowpipe and chemical tests. The darker the colour the less arsenic in it, Red Copper Ore (ruby copper). Found massive, earthy, granular, &c. Crystallization octahedral, and dodecahedral. Structure brittle . Lustre adamantine, or submetallic. Is subtransparent or nearly opaque. Detached crystals look rather like spinel rubies. Colour deep red, ruby colour, though it is often iron grey on the surface. Streak always brownish red. H. 3-5 to 4; S.G. 6. Composition per cent. copper, 88-78 ; the remainder oxygen. Heated in a tube closed at one end, it darkens. Yields globule of copper before the blowpipe. Dissolves in nitric acid. Soluble in ammonia : solution eventually azure blue. Black Oxide of Copper. Usually found on the surface, due to the decomposition of a sulphide or other copper ore. Black copper at the top of a lode may indicate some other copper compound deeper down. If the dusty powder be rubbed between the fingers and dropped on a flame, the latter will be coloured green. Soluble in ammonia : solution azure blue. THE PROSPECTOR'S HANDBOOK. Silicate of Copper. Usually as an incrustation, massive, &c. Colour bright green and bluish green. H. 2-3 ; S.G. 2 to 2'3. Contains 40 to 50 per cent, of oxide of copper. Is rather like malachite in colour, but when dissolved in nitric acid a precipitate is left, whereas malachite is quite dissolved. Malachite (green carbonate of copper). Found in botryoidal or stake ti tic masses, and as ar incrustation, &c. Structure fibrous. Nearly opaque. Colour emerald green. Streak a paler green than the colour. H. 3-5 to 4 ; S.G. 3-6 to 4. Contains about 57 per cent, of copper. Before the blowpipe it becomes blackish. With borax before the B.F. it forms a green globule, and eventually yields a copper bead. Completely dissolves in nitric acid, and so differs from other ores of a similar appearance. The blue carbonate is very like the above ; but its crys- tallization is a rhombic prism, and its streak bluish. It is impossible to enumerate more than a few of the localities where copper ore is found and its manner of occurrence. It occurs in rocks of every age and in both lodes and deposits. The usual ore in a copper lode is pyrites, which is decomposed into black oxide at the surface. In Cornwall the copper lodes, which generally run east and west, are more productive in the slates than the granites. The New Eed Sandstone of Cheshire and Shropshire con- tains certain deposits of copper, chiefly malachite ; and in the Carboniferous Limestone of Shropshire are also deposits of the same ore as well as pyrites. Copper pyrites veins traverse green slates and porphyritic rocks in the north of England. Not to mention the variety of lodes which run through rocks of various age of North America, COPPER ORES. 49 the following are a few examples of the position of certain deposits. In the Eastern States there are deposits in the New Eed Sandstone, also in the Carboniferous Limestone and Silurian rocks. In the Lake Superior district, where so much native copper is found, deposits occur in sandstones and shales, underlying greenstone, &c. There are also lodes running through the various strata. Deposits of ruby copper ore occur in Arizona between quartzose and hornblendic rocks and limestone. Lodes and deposits in Chili are worked in hornblendic and felspathic quartz rocks. The celebrated Burra Burra mine in Australia, from which splendid lumps of malachite are familiar objects in museums, consists of an immense irregular deposit of malachite and other copper ores in limestone and harder rocks, as well as in the soil. Copper deposits occur elsewhere in schistose, hornblendic, quartzose rocks, &c., and pyrites-bearing lodes through rocks of various ages. In Nevada, for example, the massive outcrops of quartz- ite are frequently stained with copper for miles owing to surface decomposition. The ore itself is, however, frequently too poor to work. Copper sulphides (with or without antimony, arsenic, &c.) often occur in gold and silver-bearing lodes ; and, therefore, though neither free gold nor a silver compound may be noticed on the outcrop, assays should certainly be made. 50 THE PROSPECTORS HANDBOOK. GOLD. To detect free or native gold in a piece of specimen rock, in saad or gravel, the sample should be carefully examined by means of a magnifying glass, if the eye is insufficient. The particles of gold, if present in the free state, will probably be distinct, whether wet or dry, and can easily be distinguished by an expert from discoloured mica, iron, or copper pyrites. The usual colour of the metal is well known : but it must be borne in mind that in some localities, such as in New South Wales, Australia, and Costa Rica, it is often found of a very light colour ; indeed, some- times it looks like not very yellow iron pyrites. Gold pre- sents the same colour from whatever direction it is looked at. To the prospector this is a guiding test. If a gold grain be detached from a rock, or selected from sand or gravel, it can be flattened out by hammering and can be cut in slices, whereas those substances likely to be mistaken for gold are reduced to powder when pounded. Iron pyrites is too hard to be cut by a knife, while copper pyrites affords a greenish powder. Besides, pyrites ore, when heated, gives off a sulphury odour. Mica, which when discoloured may be frequently mistaken for gold, is not sec tile, and has a colourless streak ; it can thus be distinguished from the precious metal. It may be well, too, to know that a speck of gold is not altered in colour or appearance by hydro- chloric acid. As the quantity of gold in rock is usually very small and to be payable it need not be otherwise the most and only accurate way of determining its quantity is by means of scorification or fusion in a crucible, and afterwards by the cupellation process. This, however, is not always practicable in an out-of-the way place, and, con- sequently, more simple means are generally sought for by prospectors in order to obtain a rough assay ; and as gold is usually, though not always, met with in the pure metallic state, such are to be in a great measure depended upon. At the same time, it must be remembered that frequently the gold occurs as a very fine powder, invisible to the eye or even under a magnifying lens, and also that the grains probably due to sulphur or arsenic may be coated with a TO "PAN OUT" GOLD. 51 film, which prevents them from being recognised, and also from being capable of amalgamation with mercury until they have been roasted or undergone some operation.* To " pan out " gold-bearing matter, the gravel, sand (or rock powdered but not too finely), is placed in a flat bot- tomed basin or pan, the diameter of which is about a foot, and two or three inches wider at the top than at the bottom. The pan, three-quarters full of ore, should be placed at an inclined position under water, or else water poured into it, and by shaking and agitating the contents of the pan by a kind of oscillatory motion, the lighter portions of the ore are allowed to run over the side of the vessel, until, after much washing, the heavier particles, such as gold, iron sand, &c., settle at the bottom. The iron sand, if magnetic, can be separated from the yellow metal by a magnet, or els< can, when dry, be blown away by a gentle blast of air. In Brazil a wooden vessel (a " batea ") serves for the " pan." A little preliminary practice in " panning out " will be of use to any one who anticipates actual work. Place some powdered lead (or copper or iron pyrites) with a good quantity of gravel or sand. Wash the whole with water so that all soluble or easily suspended matter may be got rid of, and thereby the separations may be more clearly observed. Now fill the pan with a fresh supply of water, and shake the whole round about, and chiefly from side to side several times, to allow the heavier matter to settle down (and out of view) underneath the gravel. By tilting the pan a little away from the body,, and still shaking it, the lead will still seek the lowest level, and the water may be made to wash some of the gravel over the rim (Fig. 35). By several repetitions of these processes a skilful operator will be able to get rid of all the matter except the lead. Supposing, however, that the beginner lacks the proper adroitness, or is afraid of washing away the lead, he need not carry the operation so far. But if, towards the la{5 stage, he finds a small quantity of, though sufficient, gravel to entirely conceal the presence of the metal, then, by tilt- * All large stones or large grains should be removed from gravel and sand, and clay should be well broken up and finely divided in the water, before " panning out" is commenced. 5 2 THE PROSPECTOR'S HANDBOOK. ing the pan to one side and away from the body, and allow- ing the little water to flow a few times in one direction round the bottom of the pan and over the gravel, some of the gravel will be washed along with the water, and the metallic matter will remain behind (Fig. 36). If such trials are successful with copper (s. g. 8*75) and lead (s. g. 11*85), they certainly would be with gold (s. g. 19*35). When the gold is of so fine a nature as to float, the operator should pour water on the floating particles, so that Fias. 33, 34, 35. The arrows denote the direction of the flow of water. their upper surface would no longer be dry ; thus some of the gold might sink to the bottom of the "pan." The following is another method of obtaining the free gold from a quantity of ore ; and it may be noted that the surface quartz with iron or other stains (which signify sul- phides deeper down the lodes) may be tried for gold by the amalgamation process.* Finely powder a quantity of ore along with water. Add mercury, at the rate of about 1 oz. * Quartz, if placed in the red hot part of a fire for a few minutes, and then thrown into cold water, can afterwards be quickly pow- dered. TO "PAN OUT" GOLD. 53 of mercury to 8 Ibs. of ore, and, if obtainable, a little cyanide of potassium. Grind the whole for two or three hours until the gold and mercury thoroughly amalgamate. Add water, and when the amalgam has settled at the bottom of the vessel pour the lighter matter off, collect the amalgam and squeeze it through chamois leather. The residue must be heated to dri^e off any mercury remaining, or if the amalgam be treated with nitric acid, the mer- cury will be dissolved and the gold left. An addition of a little sodium will assist the amalgamation and prevent loss due to " flouring." Sometimes as much as 30 per cent, of what ought to be the proper yield is lost in the tailings in a FIG. 36. free milling ore. On alluvial diggings, the operation of washing the gold dirt is usually conducted by means of sluices, having an inclination of a very slight gradient. These sluices consist of a series of troughs formed by planks nailed together, the length of each being about 10 or 12 feet, the height 8 inches to 2 feet, the width 1 to 4 feet. By making one end of the bottom plank of each trough 4 inches narrower than at the other, the troughs can be telescoped into one another, and so a sluice of very great length can be formed. Across the inside of the bottom planks small narrow strips of wood, 2 inches or so thick, and 3 or more inches wide, are fixed across, or sometimes at angles of 45 to the side of the trough, at short intervals apart. Eunning water washes downwards the earth thrown into the sluice, which is open on the top side, and the gold dust accumulates (sometimes assisted by the aid of mercury allowed to trickle out of a vessel from riffle to riffle) in front of the bars, while the lighter matter is washed downwards. 54 THE PROSPECTOR* S HANDBOOK. TELLUBIDES IN GOLD ORES. The tellurides have usually a light grey colour, though some are dark grey and some have a slightly yellowish tint, are usually brittle (though one is sectile), and some- times scaly, or film-like; and all have a metallic appearance. The specific gravity of the most valuable is high, viz. : 7 to 10. Most can be scratched by the nail, and all by a copper coin. Before the blowpipe, a brilliant greenish-blue luminosity is distinctly seen near the test-piece. When boiled in sul- phuric acid, a telluride imparts a pinkish colour to the liquid, which becomes greyish if water be added afterwards. A telluride can usually be soon fused to a globule. ; Native Gold. Found as grains; laminae, sometimes threadlike; nuggets, etc. There is always a small rf >vww amount of silver in the gold if FIG. 37. SECTION SHOWING THE TWO CONDITIONS UNDER WHICH GOLD is USUALLY FOUND. 1, Granitic and gneissic rocks, often containing gold finely") Traversed by quirtz disseminated. 2, Micaceous, taloose, and argillaceous ? veins containing slaty rocks, Laurentian and Cambrian. } gold. 3, Silurian and Devonian strata. 4, Carboniferous limestone and grits. 5, Coal measures. 6, Permian and newer rocks. 7, 7, 7, 7, Drift filling hollows in rocks, with gold, especially at the base of the drift. (sometimes, as in California, nearly 10 per cent.), and fre- quently other metals. Colour yellow. H. 2-5 to 3; S.G. 12 to 20. With carbonate of soda or charcoal before B.F. it yields a yellow bead, easily hammered out or cut. If the pow- dered ore be dissolved in aqua regia (4 parts hydrochloric and 1 part nitric acid), a purple precipitate will be formed, GOLD. 5$ when protochloride of tin is added to the solution ; or a dark brown powder (really pure gold) will be precipitated when a solution of sulphate of iron (copperas) is added. Gold, nearly invariably in a native state, is very widely distributed over the globe, and is obtained from the gravel, sand, clay, "drift beds," washed down from gold-bearing strata (sometimes the rich part of the deposits has brown ferruginous matter associated with it), or else from quartz lodes traversing the older slaty and metamorphic rocks and less abundantly in granite. It is also found scattered about in rocks of a granular nature.* The ordinary gold-bearing lodes and deposits occur as represented in Fig. 37, which represents the structure of the Ural Mountains. Iron pyrites, copper pyrites, magnetic iron, blende, galena, &c., are some of the metallic minerals often very commonly associated with gold in a lode, the iron pyrites in veins of a gold- bearing district nearly, if not always, containing a certain amount of the precious metal. On the surface of a lode the gold specks may perchance be noticed, by the eye or lens, in the cavities of the brown Honeycombed quartz rock, although free gold may be invisible in the pyrites rock deeper in the lode and unexposed to atmospheric and other changes affecting the surface portions. Taking for granted that gold is found under the usual circumstances heretofore mentioned, one must remember it has been payably obtained in unexpected ways : for example, in sinter, in trachyte, in very peculiar conglomerates, &c. Usually the discovery of alluvial gold leads to that of lodes in the neighbourhood ; but oecause gold deposits are not found, it does not follow that the country is non-auriferous. So, too, because gold is not noticed in the outcrop of a lode, it does not follow that the lode is necessarily an unprofit- able one. It would be out of place here to discuss the theory of how gold in veins was originally formed. In alluvial deposits the grains are usually worn into shape, and so in some other deposits. But it may be remarked that in certain con- glomerates the gold is found in thin plates, a fact which suggests that the law of gravity does not apply to the di.s- * Such as granite, diorite, gabbro, &o. 56 THE PROSPECTOR'S HANDBOOK tribution of the metal in these as it usually does in most deposits where the portions nearest the bed-rock are richest. Here, too, it may be mentioned that in conglomerates, such as the South African, the gold is not chiefly in the pebbles, but in the matter which binds them together. Nearly every country in Europe has yielded gold under the usual circumstances, in deposits and veins in rocks older than the carboniferous formations, in metamorphic rocks, &c. The precious metal has been found not generally very lucratively in the muds and sands of such rivers as the Danube, Elbe, Oder, Weser, Ehine, and in many of the lesser rivers, and consequently some parts of the hill districts through which they pass contain auriferous rocks. Austro- Hungary is rich in lodes (the gold being sometimes found as a telluride), and the extent of the gold-bearing alluvial de- posits of the Ural Mountains is enormous. (See Fig. 37.) In the British Isles gold is found in various parts of Scot- land, in Ireland, in Cornwall, Devon, Lancashire, and more especially in Wales. In North Wales not only has it been gathered from the beds of rivers and sand on the seashore, but has been and also is being obtained from lodes (one of which was worked by the Eomans). The auriferous quartz reefs (carrying iron pyrites, galena, &c.) run through slates of the old fossiliferous rocks (Lower and Upper Cambrian), and at the intersection of these gold-bearing lodes with other copper and silver bearing ones the reefs are some- times rich. The Western States and territories of North America (especially California), some of the Southern States of North America, Canada, Nova Scotia, British Columbia, Central America, Chili, Venezuela, Brazil (some of the mines have for ages back been worked very lucratively), Australia (Queensland, Tasmania, South Australia, Western Aus- tralia, New South Wales, and especially Victoria), New Zealand, West Coast of Africa, South Africa, India, &c., Borneo, New Guinea, Philippine Islands, Ceylon, Mada- gascar, Persia, and others unmentioned, are all gold-bearing countries. Some of the conditions in which gold is met with in a few of the leading places are herewith given. OCCURRENCE OF GOLD. 57 AUSTRALASIA. Victoria. In quartz reefs, mostly through lower Silurian rocks, and a lesser number through Upper Silurian. The direction of the majority of the first set is \V. of N., that of the remainder E. of N. Not only have the ordinary allu- vial deposits, as generally found near the surface in drifts washed down from the gold-bearing lodes in the higher land, being extremely rich, but also (as in some parts of California) the beds of ancient streams which have been covered by other aqueous deposits over which lava once flowed. The following diagram will exemplify the position of such a rich " gutter " or " deep lead " : SSI. MNW : / ^r^Z-r^ ^Ttf^-^ S ^ FIG. 38. SECTION OF THE OLDER BRIFTAL GOLD DEPOSITS NEAU BALLARAT. Scale : Hor. 1" = 10 chains ; Vert. 1" = 320 feet. a, Drift. &, Basalt, c, Black and red clays, d, Basalt, e, Light coloured clays. /, Basalt. 1,1, 1, Auriferous drift. The saddle reefs of Bendigo lie between such strata as sandstone and sandstone, or sandstone and slate ; and are met with chiefly at anticlinals, tapering out in depth. Sandstone FIG. 38A. EXAMPLE OF 8 j DDLE E^EF FORMATION. 58 THE PROSPECTOR'S HANDBOOK. New South Wales. In lodes through Silurian, Devonian, and Carboniferous rocks. In lodes at junction of diorite and serpentine ; also through diabasic rocks. In sandstone, conglomerates, &c. Queensland. In quartz veins, mostly through metamor- phic rocks, though sometimes through granite and syenite, and in alluvial deposits derived from these. At Mount Morgan the auriferous deposit has probably been the result of a geyser, the gold being contained in a siliceous sinter. In some parts the matrix is aluminous ; in others, ironstone predominates. Also in lodes through diorite. West Australia. In ordinary lodes or compound lodes in diorite (notably in Coolgardie district), in diabase, in diorite schist, micaceous schist, chlorite schist, hornblende schist, talcose schist, granite, slate, shale, kaolin, serpen- tine, &c. In some places the lodes are interbedded with schists. The country rock of the Black Flag district is hard felsite, porphyry, &c. At the Great Boulder the gold-bearing rock contains a mixture of quartzose ironstone, felspathic material, &c. The veins run through hornblendic and diorite schist. Gold is found at Hannan's in diabase dykes, &c. Eich tellurides are frequently found in depth. At Nullagine, in the north-west, there are gold-bearing conglomerates (also diamondiferous) somewhat similar to the " banket " of the Transvaal. Of some of the minerals in which gold occurs unex- pectedly may be mentioned jaspei;, ' graphite, quartz crystals, chrysoprase. It is also found in sinter, felspar- porphyry, &c., and also disseminated in schist, granite, &c. New Zealand. In beds of rivers, in valley bottoms, and on flat land as a deposit, sometimes in a conglomerate for- mation, along the seashore mixed with magnetic iron, in glacial drifts, &c. In quartz veins through metamorphic rocks, also through andesite. New Guinea. In auriferous black sand. In a deposit of decomposed slate, quartz rock, and conglomerate, above which are leaf -bearing clays. GOLD IN SOUTH AFRICA AND AMERICA. 59 ASIA. India. Gold is found in a very great many different localities, and both in veins and alluvial deposits. In the Wynaad are gold-bearing reefs running through granitic and metamorphic rocks. Ceylon. In yeins through chloritic and micaceous rocks. SOUTH AFRICA. Lydenberg. In fissure veins ; in seams of quartz and crys- talline conglomerate between beds of shales, sandstones, and schists. De Kaap Valley. In fissure veins ; in nearly vertical beds of quartz and quartzite (sometimes carrying sulphides) be- tween layers of schists and shales. Witwatersrand. Chiefly in quartz conglomerate. Quartzite separates the reefs in the main reef series. The conglomerate ("banket") consists of whitish or greyish quartz pebbles cemented together by irony quartzose matter in which is the gold ; sometimes the gold is met with as a film on the outside of the pebbles. In some of the other reefs the quartz pebbles are of various colours. As depth is gained, instead of metallic oxides, sulphides are found. Some of the gold is found as crystals. The " banket " conglomerates are newer than the schists and shales with compact quartzite (some of which, however, are gold-bearing) occurring in many districts. In West Africa there are formations like those in the Transvaal. Elsewhere are reefs in granite, gneiss, slates, &c. The Main Reef series crops out at Johannesburg. Half a mile or so south is the Bird Eeef series. Another mile further south is the Kimberley Reef series. Two miles beyond is the Elsburg series (seven reefs). All these are stratified with quartzites. Beyond there are l miles of basaltic rock, then quartzites with the Black Reef, which is nearly flat, while the reefs of the former series dip from 40 to 80 South, the strike being nearly E. and W. At the outcrops the conglomerate pebbles are not so 6o THE PROSPECTOR'S HANDBOOK. compactly cemented together as those deeper down, and have a reddish brown colour on the outside and in the cementing material. In depth the conglomerate is usually greyish, and in the hard siliceous cement small crystals of iron pyrites are scattered about. ManicaandJMaskonaland. Quartz lodes in diorite, schists, granite, &c. Gold is sometimes found scattered about in diorite. AMERICA. Canada. In alluvial deposits above talcose and other schists ; in lodes through granite, schists. In fahl-bands, &c. In Ontario the gold-bearing veins are usually in Huronian (pre-Cambrian) country rock. In some places the gold is found disseminated through schist, porphyry, &c. Nova Scotia. In quartz lodes through serpentine ; in saddle reefs, not unlike those in Australia, &c. British Columbia. Lodes in diorite, between dykes and diorite, &c. California. In extensive alluvial deposits at the base of \JsOOse' (. _ \ Coarse (roLdbearvng Gravel FIG. 39. SECTION OF SPANISH PEAK DEPOSITS (CALIFORNIA). the Sierra Nevada, in the beds of modern and ancient streams, in magnetic iron sand, in lodes through granite, GOLD IN SOUTH AFRICA AND AMERICA. 61 gneissic and other metamorphic rocks, in seam diggings of decomposed bed-rock with irregular seams of auriferous quartz. (Fig. 1.) In Placer county the lodes running E. and W., also N. and S., traverse syenite, also metamorphic slate. In Nevada county certain lodes run N.W., and also N.E., the country rock being granite, greenstone, and slate ; generally speaking, the lodes run through metamorphic schists, or greenstone, alternating with belts of syenite. In the Eocky Mountain regions (Colorado, Montana, Da- kota, New Mexico, &c.) placers and auriferous lodes are plentiful. As a rule the lodes run through granitic rocks and metamorphic schists and slates, gneiss and quartzite, the gold being associated with iron pyrites, galena, blende, silver ore, &c. So, too, elsewhere in North America. Gold Lavcu Sandstones & Shades irv Twrvwntal strata. FIGK 40. SECTION OF A PART OP TABLE MOUNTAIN (CALIFORNIA ). is sometimes found as a telluride (in Colorado, &c.), at Boulder in lodes through micaceous schists, gneissic granite, c., between granite and porphyry. Also in West Austra- lia, New Zealand, Transylvania, Hungary, &c. At Cripple Creek, Colorado, some lodes run through andesite. At Telluride, Colorado, some gold and silver- bearing veins are in rhyolite, augite-andesite, andesite breccia, &c. At Silver Cliff, Colorado (Bussick Mine), zones of various sulphides surround pieces of country rock, and carry silver and gold, Tellurides, too, occur. THE PROSPECTOR'S HANDBOOK. In Utah, in one district, the precious metal is associated with cinnabar in a formation through limestone. In British Guiana, in the neighbourhood of some of the alluvial diggings, the country rocks are chiefly granitic, syenitic and metamorphic. Eruptive dykes are plentiful. As mentioned in the introduction to this book, the pros- pector should not necessarily confine his explorations to any particular district in an auriferous country. For instance, in Western Australia there must be large tracts of land which merit a systematic examination, notwith- standing that at the present time there are gold-bearing areas in the north (Kimberley), in the north-east (Pilbarra and Ashburton), in the east (Murchison), and in the south (Yilgarn, Coolgardie, and Dundas). So, too, British Columbia offers a large field for prospect- ing ; also many yet unexplored parts of Africa south of the equator. The Rand " banket " deposit, so especially rich in the precious metals, is known to be of very great extent, and other valuable conglomerates may yet be discovered in other regions, though perhaps not noticeably continuous with these. When once the real origin of the gold some- times found in crystals in the " banket " is really known, attention may be perhaps paid to various localities in various parts of the world where like natural processes may \J have taken place in depositing the gold. The very ocean contains how uniformly is difficult to assert gold in solu- tion ; and if it has done so in the past ages, one need not be astonished to know that in certain places where, for instance, the salt water has been evaporated, or where nature's precipitants not, of necessity, like those employed in the laboratory have thrown down the metal from its solution, gold fields, yet to be worked, may exist. Suffice it to remark, gold seems to be very much dis- tributed throughout the world ; and consequently the pros- pector should keep his eyes open wherever he goes and get rid of the notion that good specimens of gold in lode, quartz, or alluvial deposits are the only desiderata so far as he ii concerned in his searchings. GOLD IN SOUTH AFRICA AND AMERICA. 6ib In many mines, where labour, &c., is cheap, and the quantity of ore great, a few pennyweights of gold to the ton will pay to extract, and even in a mine where the ore yields averagely nearly 1 J oz. per ton, the amount of gold in bulk is very small compared to that of quartz (say equal to 5 sovereigns in 14 or 15 cubic feet of quartz). Thus it really matters Httle whether the specks of gold are visible to the naked eye or distributed in a very finely divided state throughout the mass, so long as it is recoverable by some of the many methods now in use, and of course likely to be improved upon in the future. These fac*s certainly suggest an important lesson to the prospector, viz. that it behoves him to explore a country with a mind open to new impressions. If he does not do so, for instance, in a large tract of land like West Australia, where mineral wealth seems to have been so bountifully distributed in so many districts, he will be apt to overlook much that might be valuable. Since the sixth edition was published (1895), I have returned from a hurried vii?it to South and East Africa, and I think it worth while to mention here one point that not only applies to South Africa, but also to many other countries. It is that in localities where there is much flat or slightly undulating land, as in the extensive Karoo, the greater part of the country is really most imperfectly ^prospected, simply because soil, drift, &c., conceal thebed- / rock. In Barberton district, which is hilly or mountainous, geological formations are exposed, but this is not the case in most parts of South Africa. That there may perchance be many more auriferous " banket " reefs or quartzites con- nected with, or distinct from, those already known to exist, no one can dispute, and it is not unreasonable to believe that in the future more diamond-producing mines in Orange Eiver Colony or elsewhere may be discovered. It is true that a slight elevation above a diamondiferous "pipe" formation may, in some instances, have been noticeable ; at the same time I have heard that in other instances the converse has been the case, or the elevation was not apparent. In British Guiana, too, much flat land or forest land covered with soil, containing the accumulation of vegetable 6ic THE PROSPECTORS HANDBOOK. matter, has retarded discoveries. Of course an outcrop, here and there, of hard rock such as quartz or quartzite may be met with ; however, not by any means always. Therefore, especial attention should be taken to explore the banks and beds of rivers and dry creeks, as not unfre- quently detached pieces of quartz, &c., and sometimes the lode or deposit formation itself, may be noticed in the river or creek bed. There is another point which although it is mentioned elsewhere in this book cannot be borne in mind too care- fully, and that is, that the searcher after minerals should not expect to find free gold or indications of a mineral staring him in the face ; he should rather assume that these may exist, and, in consequence, have samples of rock pro- perly assayed. It is unreasonable to expect an ounce reef to show much free gold even on the outcrop, or by panning out, especially if the gold is in a very finely-divided state. Many 3 7 ears ago, I visited a very extensive gold mine in New Zealand, and never saw a trace of gold in the immense heaps of ore ready for crushing. In this mine the gold was found in the free state and not much mixed with sulphides. So, too, in one of the large mines of Johannesburg a fifteen-pennyweights-to-the-ton mine the output from which is more than 10,OCM tons per month, the same thing occurred, the gold being concealed, in a very fine state, in the iron pyrites crystals. In connection with precious stones, mention has been made of a small instrument which, so long as a certain amount of experimenting has been previously made with specimens, .might be of much utility to prospectors who usually know but very little about gem stones, and yet who are very likely to meet with them in alluvial washings. Finally, 1 take the opportunity of reminding the pro- spector who has to deal with surface rocks of a point of great importance. Eocks and minerals have to be written about, more or less, as if they were cabinet specimens, although (as every one will understand) many of them have been weathered for thousands of years. Even a description of the appearance of an unweathered rock does not fix itself in a student's mind so well as does the handling or GOLD IN SOUTH AFRICA AND AMERICA. 6id the examination of a specimen. For this reason, I should advise any one who intends setting out on an exploration to make himself as familiar as he can beforehand with the appearance of the most important rocks such as granite, diorite, schists, silurian rocks, &c., and to examine as many gossans as he can, as well as all kinds of oxides, not forgetting tinstone, in various colours ; carbonates, chlorides, &cr, of the various metals. After which he should learn all about the sulphides and tellurides of metals, which may be met with deeper in lodes or deposits. But he must especially remember, that while he is busy with surface-matter, the mere study of rare and beautiful cabinet specimens, with their perfect crystals, will be of little use to him. Let him also remember, in the concluding words of the late Mr. D. C. Davies, F.G.S., in "Metalliferous Mines and Mining " (Crosby Lockwood and Son), that " mining is a business for the strong and adventurous." " It is an honourable pursuit ; for he who wins the precious things of the everlasting hills " fulfils no common part in the economy of the world, 3a THE PROSPECTOR'S HANDBOOK. IRON. When heated before the blowpipe some of the ores are infusible, while most become, if not naturally so, attractable by the magnet. When the test is not destroyed by the presence of other metals, iron in a mineral when heated with borax on a platinum wire in the inner flame produces a bottle-green glass ; in the outer, a dark red, when hot ; a light red, when cold. Iron Pyrites (mundic). Crystallization usually cubical ; also octahedral, &c. Lustre frequently bright metallic. Colour yellow of different shades. Streak brownish black. H. 6 to 6-5 ; S.G. 4-5 to 5. Composition about half iron and half sulphur. Strikes fire with steel, and has slightly peculiar smell when broken. If heated before B.F., sulphur fumes are given off, and eventually a globule of metal, attractable by rhe magnet, is obtained. The powder of iron pyrites is very slowly soluble in nitric acid. This ore carries gold in either a small or great quantity, and is generally to be found in gold-bearing and other lodes, oxide of iron, colouring the quartz brownish, representing at the surface the decomposed iron pyrites such as exists in the vein deeper down. The mineral is often mistaken for copper pyrites and sometimes for gold, but its being too hard to be cut by a knife is a distinguishing test. Iron pyrites is not employed for the extraction of iron ; it is the chief mineral, however, from which sulphuric acid is obtained. In Spain are very rich deposits from which most of the ore brought to England is mined, although the Coal measures of this country are productive. Magnetic Pyrites. Crystallization hexagonal prisms, &c. Colour between copper red and yellow, inclining to bronze. Streak greyish black. IRON ORES. 63 H. 3-5; S.G. 4-4 to 4-6. Composition about 60 per cent, iron, the rest sulphur. In the outer B.F. on charcoal, a red oxide of iron globule is formed ; in the inner flame, fuses and yields a black mag- netic globule having a yellowish fracture. It is not so hard as iron pyrites, and is slightly attracted by the magnet. Arsenical Pyrites (mispickel : often called mundic by miners in Cornwall and Devonshire). Crystallization rhombic prisms modified on the angles, &c. Colour silver white. Streak greyish black. Lustre shining. H. 5-5 to 6; S.G. 6-3. Composition about 35 per cent, iron, the rest arsenic and sulphur ; cobalt sometimes occurs in the ore. Befoie B.F. a magnetic globule is obtained, and a smell of garlic noticed. Strikes fire with steel, and a decided odour of garlic noticed. Heated in a tube a sublimate is obtained. Specular Iron (haematite). Crystallization rhombohedral ; some crystals are thin hexagonal tables with oblique edges. Colour dark steel grey in some varieties, but red in some earthy ones. Streak powder invariably dark cherry red. H.5-5; S.G. 4-5 to 5 -3. Composition 70 per cent, iron, the rest oxygen. Infusible before B.F., but with borax gives a yellow glass in the outer flame, a green glass in the inner flame. Varieties of this ore are : Specular iron of a metallic lustre. Eed haematite an opaque mineral, not of a metallic lustre, brownish or red in colour. Has a radiated structure. Ked ochre and red chalk soft and earthy, generally con- taining a quantity of clay. 64 THE PROSPECTOR'S HANDBOOK. Jaspery clay iron clay ironstone, &c. Micaceous iron ore (a scaly variety) is used as the basis for a certain kind of paint. Magnetic Iron Ore (loadstone). Colour dark iron grey with metallic lustre. Streak black. Structure brittle. H. 5-5 to 6-5; S.G. 5 to 6-1. Composition per cent. peroxide of iron, 69 ; protoxide of iron, 31. Infusible before B.F. Yields bottle-green glass when neated with borax in inner flame. If powdered, the iron can be separated from impurities by the magnet. Not acted on by nitric acid ; but when powdered is soluble in hydro- chloric acid. Masses of specular iron ore and magnetic iron may sometimes be mistaken for one another; the difference of streaks easily distinguishes them. This ore is the most important in the north of Europe. Brown Iron Ore (limonite). Sometimes earthy. Massive, with botryoidal and smooth surface, &c. Structure fibrous. Colour brownish yellow and coffee colour. Streak yellowish. Lustre dull or submetallic. H. 5 to 5-5 ; S.G. 3-6 to 4. Composition 85 per cent, of iron peroxide, of which seven-tenths is pure iron. Before B.F. blackens and becomes magnetic. Gives bottle-green glass in the inner flame when heated with borax. Varieties : Brown haematite Botryoidal, stalactitic, &c. Yellow and brown ochre Earthy. Bog iron ore Of a loose, friable texture. Found as a black or brownish earth in low swampy ground. Brown or yellow ironstone Hard and compact. IRON ORES. 65 Franklinite ( an American ore). Colour dark black. Streak dark brown. Structure brittle. Composition 66 per cent, peroxide of iron, manganese, and zinc. In appearance is something like magnetic iron, but less metallic. Copperas (green vitriol). Colour greenish white. Lustre glassy and sub transparent Structure brittle . Contains 25 per cent, of oxide of iron, also sulphur and water. It is formed by the decomposition of iron pyrites. Vivianite. Crystallization oblique prisms. Lustre pearly or glassy. Colour deep blue to green. Streak blue. H. 1-5 to 2; S.G. 2-6. Composition 42 per cent, protoxide of iron, phos phone acid, and water. Becomes opaque before the blowpipe. Spathic Iron (iron spar, carbonate of iron). Sometimes massive, with a crystalline structure Crystallization hexagonal, rhombohedral ^c. Lustre glassy or pearly. Colour yellowish grey to rust colour ; becomes brown ish red to black on exposure. Streak uncoloured. H. 3 to 4-5 ; S.G.- -37. Composition 62 per cent, of protoxide of iron, car bonic acid, &c. 66 THE PROSPECTOR'S HANDBOOK. Before B.F. it blackens and becomes magnetic. Colours borax green. Dissolves in nitric acid, but, though a car- bonate, does not effervesce much, unless in a powdered state. Heated in a closed tube, often decrepitates, and turns black and magnetic. Clay ironstone of the Black Band seam is an impure variety. The oxides and carbonates of iron are the principal ores, and their gangues are calcareous, argillaceous, siliceous, or bituminous, their value depending in a certain degree on the associated minerals. Thus : In spathic ores, 5 to 15 per cent, of manganese or carbonaceous matter in a clay stone is an advantage ; whereas some iron ores are de creased in worth by being associated with iron pyrites, &c. Magnetic iron ore occurs in granite, gneiss, schist rocks, clay slate, and limestone. Remarkable deposits of red haematite occur in Carbon- iferous, Cambrian, Silurian, and Devonian rocks. In Cum- berland, North Lancashire, and Wales, veins run north and south in mountain limestone. Brown iron ore deposits occur in Carboniferous Limestone and Lower Coal measures in several places in England and Wales , also in the Lias, Oolite, and Lower Greensand of some places. In Spain brown haematite is found in a cretaceous formation. Spa- thic ores occur in carboniferous rocks, as well as in Devonian and older rocks. Clay ironstone is found in shales and clays of the Coal measures, also in Lias formation. The Titan if erous iron ore, sometimes massive, but usually in the form of dark black sand washed down from the rocks in the country around, is very plentiful in some parts of North America, New Zealand, &c., and is often associated with gold, gems, heavy metallic compounds, &c. Unfor tunately the ore is rather refractory. It can be distinguished from specular iron (for which it might be mistaken) by its black streak. Lead. Lead compounds, if heated with carbonate of soda on charcoal before the blowpipe flame, yield malleable metal, and also 9 yellow oxide of lead incrustation. GALENA. 67 If dissolved in nitric acid, the white sulphate of lead may be thrown down as a precipitate by adding sulphuric acid ; or as chloride of lead by adding hydrochloric acid. As, however, other chlorides might be formed at the same time, the precipitate should have ammonia added to it, when, if chloride of lead, it is unaltered. Galena (the principal ore of lead}. Crystallization cubical and cleavable in cubes, also octahedral. Lustre shining metallic ; the surface may be dull, but the fracture is brilliant. Colour lead grey. Streak lead grey. H. 2-5; S.G. 7-5. Composition when pure, 86*6 per cent, lead, the rest sulphur, Unless heated carefully in the B.F. it is apt to decrepi- tate, but eventually yields a globule of lead. Can be decom- posed by nitric acid. Galena can be distinguished from silver and other ores by blowpipe and chemical tests as well as by its characteristic cubical cleavage. The ore usually con- tains a perceptible amount of silver, and its presence may be observed by dissolving the ore in nitric acid and dipping a piece of bright copper into the solution, when a silver film will be formed. A galena ore should always be care- fully assayed for silver, as sometimes it is very rich. It is an erroneous notion that fine-grained galena is more argenti- ferous than a coarse-grained one, though it might be in a particular district. Galena is frequently found in gold- oearing lodes. Carbonate of Lead (white lead ore). Often found near surface of a galena lode. Compact, earthy, or fibrous masses. Crystallization prismatic, &c. Structure brittle . Lustre glassy or adamantine ; is transparent or trans- lucent, when pure. Colour white or greyish (sometimes with a bluish tinge) and often discoloured brown. 68 THE PROSPECTOR'S HANDBOOK. Streak colourless. H. 3 to 3-5 ; S.G. 6-5. Composition 75 per cent, of lead, the rest carbonic acid, &c. Before B.F. a lead bead is obtained. If dissolved in nitric acid, and a piece of clean zinc be dipped in the solution, brilliant lead laminse will be precipi- tated on the zinc. Effervesces in acids. Eed oxide is some- times found on surface of lead ores, notably at Leadville, Colorado, on the carbonates. Specimens of a carbonate should always be examined for fragments of chloride of silver or chlorobromide of silver. Pyromorphite. Colour greenish, sometimes bright grass green, the hexagonal crystals having a greasy lustre, also yellowish, brownish, and sometimes dull violet. Streak whitish or yellowish. Lustre more or less resinous ; generally translucent. H. 3-5 to 4 ; S.G. 6*5 to 7. Contains 78 per cent, of lead, as well as phosphorus, &c. Heated on charcoal before the B.F., a globule is formed which crystallizes on cooling, while a yellow oxide of lead incrustation is seen on the charcoal. With carbonate of soda in K.F. yields a lead bead. Is soluble in nitric acid. Chromate of Lead. Is a yellowish mineral containing protoxide of lead and chromic acid. It blackens before the blowpipe and leaves shining globules of lead in the slag. Produces a yellow solution in nitric acid. Sulphate of Lead. A white, grey, greenish, or bluish, translucent or opaque mineral, with an adamantine lustre. Contains protoxide of lead and sulphuric acid. Kather like carbonate of lead, but is softer and does not effervesce in an acid. Galena (generally mixed with other metals) is the usual OCCURRENCE OF LEAD ORES. 69 and most productive ore of lead, and is very frequently ex- tremely rich in silver. It is found in rock formations of various ages in lodes, pockets, flats, &c. The carboniferous or mountain limestones of England yield most of the lead ore, while it is also worked in the " killas " of Cornwall, a Devonian formation. It also occurs in Great Britain and other countries in the Lower Silurian rocks, in granites, gneiss, &c. The carbonate of lead deposits of Leadville, Colorado, best known for being richly argentiferous, occur between blue limestone and porphyry (Fig. 41). Galena is generally associated with quartz, carbonate of lime spar, fluor-spar, sometimes barytes, copper and iron pyrites, &c. (For the assay of Galena, see Chap. IX.) If powdered galena be heated in an iron spoon, lead can be obtained. The heat should be gradually raised at first till the pieces cease to decrepitate. After this a red heat will suffice. The following is a simple method of obtaining lead bul- lion (though not the proper amount) from an ore, and may be of use to the prospector. Erect a square furnace of rough stones. Place rough logs of wood at the bottom, above this split wood, then broken-up ore, and then wood. The fire should be lighted at the entrance, and the lead allowed to run out into a basin. MANGANESE. The principal ore is the black oxide (grey manganese or pyrolusite). Found compact or granular ; the black powder in the cavities will soil the fingers. Small brilliant crystals, like cut steel, are sometimes met with ; also botryoidal masses with a fibrous structure. ^ Lustre submetallic. Colour and streak black. H. 2 to 2-5 ; S.G. 4*8 to 5. Composition 63 '3 per cent, manganese, the remainder oxygen. Effervesces briskly with borax before the B.F. 70 THE PROSPECTOR'S HANDBOOK. Ths oxide of manganese, when heated with borax on a platinum wire, colours the bead violet to black when hot, reddish violet when cold, in the O.F. ; colourless when hot, colourless to rose colour when cold, in the E.F. If a mineral together with carbonate of soda be fused, a greenish glass will suggest the presence of manganese. Wad (bog manganese) is an earthy or compact variety of manganite, a mineral which differs from the black oxide in containing 10 per cent of water. Psilomene is a hydrous oxide of manganese which contains baryta and other sub- stances. When heated with borax produces a violent effervescence. Oxides dissolve in hydrochloric, also in a boiling solution of citric acid. Manganese spar (of a reddish colour) consists of man- ganese protoxide, silica, &c. Manganese deposits occur in different parts of the world and seem to have been derived from the metal originally scattered about in rocks of the ancient formations. MERCURY. If heated in a glass tube together with carbonate of soda, mercury compounds yield a sublimate of mercury on the cold part of the tube. Native Mercury. Is sometimes found as fluid globules of a tin-white colour. S.G. 13*6. Is volatile before theB.F., and easily dissolve? in nitric acid. Cinnabar (sulphide of mercury). This is the ore from which commercial mercury is ob- tained. Sometimes found massive, with a granular struc- ture, sometimes in a crystallized form, the crystals being brilliant, transparent, and of a beautiful carmine colour. Colour generally red, sometimes bright red; also brown, brownish black, &c. Streak red. Lustre unmetallic. MERCURY ORES. 71 Structure sectile. H. 2 to 2-5 ; S.G. 6 to 8. Contains 86 per cent, of mercury, the rest sulphur. Is volatile before the B.F. Soluble in aqua regia (4 hydrochloric acid and 1 nitric acid), bnt not in either hydrochloric or nitric acid. A piece of clean copper placed in the solution will be coated with a film of mercury. If the powdered ore be placed together with quicklime in an iron pan and gently heated, a globule of mercury will be found at the bottom of the pan. If the powdered ore be placed in a glass vessel capable of standing heat, such as a thin oil flask, and exposed to a strong flame, the mercury will form a sublimate on the upper and cool part of the vessel. If heated in a tube closed at one end, globules of mer- cury condense on the cool portion. Near the test piece a black (red on being rubbed) sublimate is formed. By placing powdered ore in the mouth of a tobacco-pipe, closing the mouth with clay, and exposing the bowl to a fair heat, the mercury may be collected on a cool surface, held so that the fumes given off may be condensed. A gold coin or a piece of clean copper placed in the fumes will soon have a deposit of mercury on its surface. Chloride of Mercury (horn quicksilver). Is crystalline and granular, of a dirty white or ash grey colour, and a yellowish streak. Frequently associated with cinnabar. H. 1 to 2 ; S.G. 6-48. Selinide of Mercury. Of a steel or lead grey colour and metallic lustre ; occurs in Mexico. The following are some of the places where cinnabar is found and its mode of occurrence : California As deposits in cretaceous rocks, &c. Idria in Illyria Disseminated through bituminous schist, limestone, or grit. Spain In veins traversing a micaceous schist. js, THE PROSPECTOR'S HANDBOOK. Australia In veins through Devonian rocks, &c. Italy In small veins through mica slate. Mexico There is a mercury-producing vein in pitchstone porphyry. South America There is a mercury-bearing ore in strata of shales and sandstones, &c. In Utah is found associated with gold. Generally speaking, mercury ores occur in both early and late geological formations. In New South Wales small rounded pieces of cinnabar have been found in a gold and gem-bearing alluvial. MOLYBDENUM. To test the presence of molybdenum in a mineral, heat it before B.F. on charcoal. A yellowish- white sublimate (crystallized near the test piece ; yellow, hot ; white, cold) is formed and a greenish blue flame. The sublimate be- comes of an azure-blue colour in the E.F. The principal ore is the sulphide, like graphite in appear ance, but easily distinguished by testing. H. 1-2 ; S.G. 4 to 5. Composition nearly 59 per cent, molybdenum, the rest sulphur. Very frequently a yellowish oxide (ochre) accompanies the sulphide as an incrustation. It contains 66 per cent, molybdenum. Molybdate of lead, yellow, affords metallic lead before the blowpipe. NICKEL. To test the presence of nickel in a mineral, by means of the blowpipe, requires great care. If heated on charcoal, together with carbonate of soda in the inner flame, a grey metallic powder, attractable by the magnet, is formed. If heated with borax on platinum wire in the outer frame, a hyacinth red to violet brown glass results when hot, a yel- lowish or yellowish red when cold. In the reducing flame a grey bead is formed. Kupfernickel (Arsenical nickel). Generally massive, kidney-shaped, columnar, arborescent, &c. NICKEL ORES. 73 Crystallization hexagonal. Colour copper red (greyish or blackish when tar- nished). Streak paler. Lustre metallic. Structure brittle. H. 5 to 5- ; S.G. 7*3 to 77. Composition 35 to 45 per cent, of nickel, the rest chiefly arsenic. Often resembles native copper, but is harder. Soluble in aqua regia, and forms a green solution which becomes a violet blue by the addition of ammonia. White Nickel (nickel glance). Crystallization cubical. Colour silver white or steel grey. Streak greyish black. Lustre metallic. Structure brittle. H. 5-5 to 6 ; S.G. 6.4 to 6-7. Composition 25 to 30 per cent, nickel, the rest arsenic Soluble in aqua regia. Emerald Nickel (a carbonate of nickel). Is of a bright green colour, and contains 28*6 per cent. of water. In addition to the above may be mentioned the prolific hydrated silicate of nickel found in New Caledonia. Colour green, light or dark. Streak light green. S.G. 2-2 to 2-86 ; H. 2-5. Gives off water when heated. Fuses in borax before B.F., and gives the ordinary nickel bead. Is a silicate of nickel and magnesia, with iron, &c. Good specimens yield 12 per cent, nickel. Is found in lodes and pockets in ser pentine rock. Matrix, cellular silica. Sometimes in a lode, the nickel is replaced by cobalt. Sometimes associated with chrome iron. Excepting the New Caledonia ore, the principal ore is 74 THE PROSPECTORS HANDBOOK. kupfernickel. It occurs in many countries of Europe, in metamorphic, syenitic rocks, &c., and is generally associated with ores of cobalt, copper, silver, lead, &c. In Canada, a deposit of nickel ore occurs between magnesian limestone above and serpentine below. On the surface of a nickel-bearing lode, some green stains may be noticed. A serpentine country is always worth prospecting for nickel, cobalt, and chromium minerals. PLATINUM. This metal is found in the native state. Occurs in grains and masses. Colour whitish grey or dark grey. Streak whitish grey or dark grey. Lustre metallic. H. 4to4.5;S.G. 16 to 21. Indium and osmium, &c., are usually mixed up with it. Wholly insoluble before the blowpipe flame. Can be dis- solved in aqua regia (4 parts hydrochloric and 1 nitric acid), forming a yellowish solution, which becomes a bright red colour when protochloride of tin is added. On account of the high specific gravity of platinum, it can be "panned out "from sand or gravel just the same as gold or other heavy metals. If platinum be dissolved in aqua regia by boiling, and salammoniac be added to the filtered solution, a granular precipitate of a bright yellow or reddish yellow is formed. When this precipitate is heated, the metal, as " spongy platinum " powder, is obtained. Platinum, though it is found in minute quantity in some metal-bearing veins, is usually met with as grains, generally flattened, in gold-bearing alluvial deposits, probably washed down from crystalline rocks. SILVER ORES. 75 SILVER. Silver ores are easily fused before the blowpipe flame, either with or without carbonate of soda. The resulting globule of metal, of its characteristic white colour, can be readily hammered out or cut by a knife. If the powdered mineral, supposed to contain silver, be dissolved in nitric acid and the solution be filtered or de- canted, the presence of silver may be known by adding a solution of common table salt or of hydrochloric acid to the original solution. If silver be present, a white precipi- tate is thrown down. As chloride of lead or mercury might also be precipitated, let it be remembered that chloride of silver is soluble in ammonia, whereas chloride of lead is un changed, and mercurous chloride blackened by it. A very bright piece of copper, placed in the original solu- tion, would be coated with metallic silver, if any existed. To test for copper, a bright knife-blade dipped into the solu- tion would be coated with a copper film. Sometimes, if a lump of silver-bearing ore be placed in a very hot fire, it will show white particles of the metal on the outside. The silver metal soon tarnishes, when exposed to the action of sulphur ; thus, if boiled along with the yolk of an egg, it will blacken Native Silver. Found as wire silver, in thin sheets, in tree-like shapes, &c., and as octahedral crystals. Colour and Streak silver white. When found in veins is usually tarnished on the surface. Structure easily cut and hammered out. H. 2*5 to 3; S.G. 1 or sometimes colourless mineral of a pearly or resinous lustre. Is greasy to the touch ; soft ; yields to the finger-nail ; can be cut into laminae which bend but are not elastic. H. 1 ; S.G-. 2 '6 to 2-8. Before blowpipe is infusible, but whitens. Becomes red with nitrate of cobalt solution. Is not soluble in either hydrochloric or sulphuric acid. Composition per cent. : silica, 62 ; magnesia, 27 ; alumina, water, iron, &c. ^-Chlorite. A dark green, generally foliated and scaly mineral. Streak, greenish grey. H. 1 to 1-5 ; S.G. 2-7 to 2-96. Soluble in hot sulphuric acid. Contains silicates of alumina and magnesia and water. cJDEomblende. There are many varieties of this mineral, mostly of a greenish black, and also whitish colour (those containing lime and magnesia, without iron, being light). Streak, white or slightly coloured. Lustre, vitreous. H. 4 to 6. S.G. 2-9 to 4. Scarcely acted on by hydrochloric or nitric acid. Unaltered when heated in a closed tube. More or less fusible before the B.F. Composed of silicates of lime, magnesia, also iron, alumina, &c. Augite. A dark green or blackish mineral, in composition like hornblende, of a pearly or vitreous lustre. Is met with in volcanic rocks. Olivine. A green or brownish transparent or translucent mineral IO4 THE PROSPECTOR'S HANDBOOK. of a vitreous lustre, found imbedded in lava or basalt. Is harder then felspar, and sometimes equals quartz. S.G-. 3 '3 to 3-5. Dissolves in sulphuric acid, less readily in hydrochloric acid ; the silica gelatinizes, Consists of silica, magnesia, iron, and oxygen. MATRICES OP VEINS. The principal ones are : Quartz. Of nearly every colour, generally white or brownish, sometimes bluish, as in the Queensland gold districts, and FIGS. 53 and 54. COMMON CRYSTALS OP QUARTZ. of a dull glassy lustre. Scratches glass, &c., but cannot be scratched by a file or knife. Is infusible alone before the ' B.F., but with carbonate of soda it dissolves to a glass. Is insoluble in acids, except hydro- fluoric. If two pieces of quartz are rubbed together in the dark, a phosphorescent light is seen. When crystallized, is usually in six- sided prisms. H. 7; S.G-. 2-6 to 27. At or near the surface of a lode the quartz has very often a honeycomb appearance, and stained brown, yellow, purple, or other colour, due to decomposed iron or copper pyrites, or other metallic substances, which may be expected to be found deeper down. Quartz is very nearly pure silica. FIG. 55. FLUOR-SPAR CALC-SPAR. 105 Fluor- Spar. Though by no means so common a matrix as quartz, it often forms or is mixed with the gangue of copper, lead, or silver-bearing lodes. Is usually purple, sometimes yellow, white, or green, and occasionally blue. If a piece be heated in a dark place, a phosphorescent light may be noticed. Fluor-spar might be mistaken for a precious stone ; its softness, however, is a distinguishing feature. Crystallizes most commonly in cubes, octahedra, &c. Crystals are transparent or translucent. H. 4 ; S.G-. 3-14 to 3-18. Is brittle. When heated in a closed tube, decrepitates and phosphoresces. Gives opaque beads when heated with borax and micros- mic salt before B.F. If melted in a tube with microsmic salt it gives off vapour of hydrofluoric acid, which corrodes the glass. If the powdered mineral be dissolved in sulphuric acid, the gaseous acid will corrode glass, and even siliceous stones. Blue John is a name given by Derbyshire miners to a blue fluor-spar. Composition : lime, 51 ; fluorine, 48. Calc-Spar (carbonate of lime).^ Generally transparent or translucent. Crystallization FIG. 56. FIG. 57. COMMON FORMS OF CALC SPAR. FIG. 58. rhombohedral, &c. Some common forms being as above. The faces are sometimes very brilliant. H. 3 ; S.G. 2-5 to 2 -8. Is colourless, topaz, or honey yellow, grey rose, violet, &c. Is infusible before the B.F., gives a very bright light, and is eventually reduced to a quicklime. It effervesces when acted on by an acid. CHAPTER VIII. TESTING BY THE WET Pitt CESS. Systematic Plan of Procedure. IN testing a mineral by the wet process, the method is to powder and thoroughly dissolve it in some liquid, usually an acid, or mixture of acids, and then to recognise the presence of some known metal or metals by the peculiarity of the precipitate produced, when a reagent has been added to the solution. If the mineral is likely to contain sulphur or arsenic or other such volatile substances in its composi- tion (such as iron pyrites, copper pyrites, galena, &c.), a- good plan is to powder and roast it in order to drive off the sulphur, and to leave the metallic portions in the form of oxide, and thus in a proper condition for easy examination. There are certain minerals, as graphite, cinnabar (the prin- cipal ore of mercury), some oxides, sulphates, chlorides, and a number of silicates, that are not soluble in acid. So as to simplify the testing of such as these, it is just as well to add to the powdered mineral about four times the weight of carbonate of soda, and to melt them in a crucible or other apparatus, so as to leave the metallic portion in a condition to be dissolved by hydrochloric acid ; but let it be remem- bered that the above methods are only suggested to render the tests more accurate than they would otherwise be. Notwithstanding that the blowpipe tests are those chiefly to be depended upon, the following wet ones may be of use in determining the presence of some of the metallic bases in many of the common ores met with ; and the apparatus required is not very large, consisting of three acids (hydro- chloric, nitric, sulphuric), potash, ammonia, protochloride of tin (if convenient) for the gold test, copper, and zinc, a few test tubes, porcelain capsules, &c.* The principal objec- tion to the wet process is the inconvenience of carrying * Also citric acid ; sulphate of iron for gold test, &c. CHLORIDE OF LEAD. about powerful acids ; at the same time, any chemist, if desired, will put them in strong and properly stopped bottles, which, when packed carefully in the compartments of a small box, will stand a good deal of knocking about. The finely powdered mineral should be dissolved in hydrochloric acid or nitric acid (the latter being a substi- tute for roasting, and is the most suitable when the sub- stance is a sulphide, or arsenide, or metallic alloy), and reagents added. Place a little powdered ore in a test tube or other convenient apparatus (such as a porcelain dish), add a little water and pour in nitric acid ; heat this over a spirit or other flame for a short time. The clear solution is called the original solution, and (if there be any undissolved matter left as a residue at the bottom of the tube) should be filtered or decanted into another test tube. To the clear solution add a little hydrochloric acid, when, if a precipitate is formed, it is, Chloride of Lead, Chloride of Silver, or Mercurous Chloride. ^ Pour all the liquid off, and then shake this precipitate with ammonia and observe the results : If dissolved it is chlo- ride of silver. Confirmatory test for silver : add potash to the original solution and a brown precipi- tate would be pro- duced. If blackened it is mer- curous chloride. Confirmatory test for mercury : add potash to original solution and a black precipi- tate would be pro- duced. Metallic cop- per (clean) placed in the solution would become silvery-look- ing. If unchanged it is chloride of lead. Confirmatory test for lead : add to original solution some sulphu- ric acid, and stir ; a white precipitate, sul- phate of lead, would be formed at the bot- tom of the tube. Suppose, however, that no precipitate was formed on the addition of hydrochloric acid to the original solution. The presence of some of the metallic bases is best determined by passing sulphuretted hydrogen gas through the acid solu- roS THE PROSPECTOR'S HANDBOOK. tion. If a precipitate is formed it may, if black, show the presence of mercury, lead, bismuth, platinum, tin, gold, and copper ; if yellow, of tin, antimony, arsenic, or cadmium ; but should no precipitate be formed, the addition of other reagents has to be made to determine the presence of iron, zinc, manganese, copper, nickel, and cobalt, &c.* The prospector will, however, find that usually his best plan is to take portions of the original solution, and to test them, one at a time, as follows : To separate portions of the original add reagents as in Table on the next page. The presence of antimony may be noted by adding a little hydrochloric acid to the original solution, and, introducing a piece of zinc a sooty black precipitate will be the result. To test a mineral for gold, the specimen must be tho roughly dissolved in aqua regia (4 parts hydrochloric and 1 nitric acid), then protochloride of tin added. The slight- est trace of gold will cause the purple precipitate (called purple of cassius) to be formed ; if a bright red solution results, there is platinum present. If, instead of the proto- chloride of tin, a solution of sulphate of iron (copperas) be added, the gold would be precipitated as a brown powder. Though, generally, testing for a metal in a mineral is most satisfactorily performed by means of the blowpipe, there are cases in which there is great difficulty in obtaining proper results; for instance, when several metallic com- pounds are combined in the same specimen. Under such or other circumstances, individual tests, by means of the addition of reagents to the original solution, are most useful. Again, the action of an acid on a mineral frequently enables the operator to determine whether the mineral is a silicate, a carbonate, &c. if the former, sometimes by gelatinization ; if the latter, by effervescence ; and the evolution of nitrous acid vapours will suggest that copper, copper pyrites, or some metalliferous substance, not an oxide, may be present. * Analogous test by fusion : If, when a mineral be fused with hyposulphite of soda, the mass is black, it denotes the presence of bis- muth, cobalt, copper, gold, iron, lead, mercury, nickel, platinum, silver, Uranium ; white, zinc ; red, antimony ; green, chromium or manga* *ese ; brown, tin or molybdenum. I ij QM 4J rd O 13 CO .M pr a o CHAPTER IX ASSAY OF GOLD. Various methods. -Fluxes, reagents, &c. General treatment of ores. Preparation of the sample. Weighing, &c. Assay ton. To construct a simple button balance and to use it. Dry assay for gold and silver. Apparatus and procedure. Fusion in a cru- cible. Scorification. Cupellation. Indications of the presence of metals known from cupel stains. To make cupels. Dry assay for lead in galena, tin, antimony. Wet assays for gold, silver, lead, copper, iron. Roasting. Mechanical assay of ores. To determine the amount of metal in an ore, there are two kinds of assay adopted. The dry method (i.e. by fusing the powdered ore with or without fluxes). The wet method (i.e. by the agency of liquids). In the principal wet assay, the ore is thoroughly dissolved in acids, and, by the addition of reagents, precipitates con- taining the metals are thrown down. In some assays, particularly those of copper, iron, zinc, and silver, a standard solution of known strength is added to the original solution by allowing it to drop gradually from a graduated burette, and when a certain change of colour has been produced, by reading off the graduated mark at the top of the liquid column in the burette the amount of metal in the ore can be accurately determined by a slight calcula- tion. At the same time more simple methods will, if not strictly accurate, give good results, and are more likely to be adopted by the prospector. Then there is the assay by mechanical means (for instance, the separating of the lighter portions from heavier by means of water, as in the " panning out " of gold in a deposit), (see GOLD, Chap. V.). In dry assays, crucibles or scorifiers capable of standing very great heat, without breaking, are generally used for GENERAL TREATMENT OF ORES. in conducting the operations, and in these the powdered ores, with or without fluxes, are exposed to heat in a furnace, the temperature varying according to the nature of the ore. The principal fluxes employed are : Carbonate of Soda, or Potash, which forms fusible compounds with silica, &c. Borax, which forms fusible compounds with lime, oxide of iron, &c. Glass, Silica, Fluor-Spar, Litharge, and others. Reducing Agents are used, such as chareoal powder, cyanide of potassium. Oxidizing Agents, such as atmospheric air (removing sulphur, &c., in the roasting process), nitre (which is very rich in oxygen), litharge, salt, &c. Desulphurizing Agents (for removing sulphur), such as air (in the roasting process), iron nails, carbonate of soda, &c. Agents to remove Arsenic, such as atmospheric air (in roasting process), nitre, &c. Collecting Agents (for collecting silver or gold), such as lead, mercury, &c. GENERAL TREATMENT OF ORES. Specimens to be assayed should not be chosen to elicit a "good assay" only. They should represent dressed ore ready for shipment. When an average portion of rook has been selected, it should be carefully powdered, if possible, in a mortar, or, in the absence of a mortar, broken up into a few pieces ; and these, rolled up in cloth or paper, should be powdered between two hard rocks. To prevent frag- ments from flying out of the mortar, a loose paper cover, with a hole in the centre for the pestle to pass through, will suffice. Some substances, especially those of a quartzy nature, will be rendered easier to crush by first being heated and thrown into water. If the ore does not contain metallic particles, the operation of powdering and sieving is compa- ratively easy ; when, however, metallic fragments are mixed in THE PROSPECTOR'S HANDBOOK. up with the bulk of the ore, they are very apt to become flattened out by hammering, and do not always present a metallic appearance. In this condition they may refuse to pass through the sieve, and an inexperienced person, not understanding that they may be the most valuable frag- ments of the sample, is inclined to throw them aside. In reality, they should be collected together and most care- fully examined. When fragments of the ore adhere to the mortar, a little powdered coke or charcoal should be stirred about in the mortar. When a dry assay or analysis is intended, the best sieve to use is the one of sixty meshes to the inch ; when an or- dinary wet assay, the eighty-mesh one ; but for the separa- tion of heavy metals, such as gold, tin, &c., from the lighter matter, by means of water and motion, the ore need not be powdered very finely. A piece of fine muslin will, in the absence of a sieve, answer ordinary purposes tolerably well, if, when the powdered ore be placed in it, the muslin be gathered together at the corners and shaken gently. After the specimen has been thoroughly powdered it should be put back into the mortar and stirred a few times by the pestle in order to evenly distribute the light and heavy particles, and then by a quick overturning of the mortar deposited on a piece of dry paper (glazed if possible). The powder may then be gently mixed by a knife or spatula, and if there be too much in quantity divided into quarters, and one or more divisions selected for the assay. The ore can then be weighed very accurately on the ore balance, after which it is ready for assaying. If the assay is one for gold and silver, the resulting button of precious metal is naturally very small (and to weigh which the very delicate button balance is used), so that great accuracy in the ori- ginal weighing of ore is necessary, as the following calcula- tion has to be made : If a weight of ore yields a certain weight of metal, what weight of metal in ounces will a ton of similar ore yield 1 If the ore is assayed for ordinary metals, such as lead, &c., then weight of resulting metal y i QA... percentage of metal in weight of sample of ore the ore. SAMPLING AND WEIGHING. 113 For weighing gold, silver, or platinum, the troy weight is sometimes used; for weighing other metals, avoirdupois. The French decimal system of grammes and decimals ^ gramme is convenient for both. (See APPENDIX.) y The management of the button balance requires vfc^v great care, and should never be used except for the preciousN^ metals, as the ores, fluxes, &c., must be weighed on a less delicate balance. To adjust and thoroughly understand the reading of the button balance needs instruction, and no one should use one until the working of it has been explained. It may be well, however, to mention that the glass slide should always be kept down except during the weighing operation, and that the apparatus should never be by any means exposed to acid or other deleterious fumes. A very good plan is to use the conventional assay ton weights in weighing the ore, as, by this conventional system, the number of ounces of precious metal in a ton of ore may be known according to the amount of milligrammes, &c., the button of precious metal weighs. Thus, in America, a conventional assay ton (A.T.) weigh- ing 29*166 grammes may be used (where 2,000 Ibs. = 1 ton); or in British countries one weighing 32-667 grammes (where 2,240 Ibs. = 1 ton). Still, there is no occasion to know the exact weight of the piece of metal used as an A.T., so long as the operator knows how to read a balance where A.T/s are made use of. If 1 A.T. of ore yields a button of 1 milligramme, a ton of ore yields 1 oz. troy of precious metal. One-tenth A.T. is a very convenient quantity of ore to take ; for if the button weighs x milligrammes, this repre- sents 10 x oz. of precious metal per ton of ore. In the absence of a proper balance, the following may be of service : Procure from a carpenter a very thin strip of pine wood (about one foot or fifteen inches long and one-third of an inch wide). Place a fine needle across by means of wax, or through the middle. Next obtain a piece of sheet tin or other metal (one inch by half-inch), and bend its edges up perpendicularly one quarter-inch on each side. On these upturned portions place the needle ends. Should the beam 114 THE PROSPECTOR'S HANDBOOK. not balance properly, trim either end by shaving off very thin pieces until it does. Now divide the strip into twenty equal parts, i.e. ten on each side of the middle, and mark them 1, 2, 3, &c., so that the 1 marks may be nearest the middle and the 10 marks at the ends. Three weights are required : One grain : Can be obtained by weighing out a piece of thin brass wire (ends bent together) on a chemist's balance. One tenth grain : To obtain this, place the one-grain weight on the 1 mark of the wooden balance and place such a smaller piece of wire, bent at FIG. 59. the ends, on the 10 mark on the opposite side, as will cause the beam to balance properly. One-hundredth grain : To obtain this, place the one-tenth grain weight on the 1 mark, and a piece of thread or such like material on the 10 mark on the other side as will cause the beam to balance properly. To weigh the Button of Gold or Silver. Place it on the 10 mark and see if 1 grain on 10 mark (opposite side) exactly balances it; if it does, the button weighs 1 grain. If the wire weight be too much, move it towards the middle of the beam to a division, until it is a little lighter than the button. Leave it on this mark. Then take the one-tenth grain, and, commencing from the end of the beam, move it towards the middle until the division reached is that one where this weight together with the first weight is just lighter than the button. Then proceed with the one-hundredth grain in the same way. Suppose, now, that the one grain weight be at 8, the one- tenth grain at 7, and the one-hundredth at 3, the weight of DRY ASSAY FOR SILVER AND GOLD. 115 the button is '873 grains, that is, a little more than eight- tenths of a grain. A rule of three sum then determines the amount of precious metal per ton of ore. If a certain weight of ore yields eight-tenths of a grain, how many grains will there be in a ton of similar ore \ (N.B. There are 32 666 troy ounces in one ton.) The number of ounces of precious metal in a ton will be known. DRY ASSAY FOR SILVER AND GOLD. In a gold and silver assay, the precious metals in the sample, either by the scorification or " fusion in a crucible " method, have to be absorbed by lead, and the resulting button of lead containing the gold and silver has to be cupelled in the muffle ; the final result being that the pre- cious metals are left on the top of the bone-ash cupel as a shining globule. As an assaying apparatus or " outfit" is to be obtained complete in a chemical apparatus shop, there is no occasion to enter into too much detail, the portable furnaces manu- factured for cupellation in a muffle being made expressly for prospectors and assayers. The most necessary articles are the following : > An ore and button balance with weights, two or three muffles, Hessian crucibles, scorifiers, cupel mould, crucible, scorificauon and cupel tongs, pokers and scrapers, an iron pestle and mortar (or a plate and rubber), box sieve (80 mesh), spatula, hammer, bone-ash for making cupels, litharge, borax, carbonate of soda, iron nails, nitre, coke, charcoal, &c., test tubes, acids, brush for cleaning the buttons. To light the fire. First, place some dry twigs and paper or wood shavings or chips, and above this slightly larger wood round about the outside of the muffle, and set light to it. Then throw in pieces of charcoal, coke, or anthracite coal broken into small pieces about the size of hen's eggs. Shut the mouth of the muffle and the grate door. Eaise the temperature as high as possible for the scorification process. Though fusion in a crucible is very convenient for poor gold and silver ores, inasmuch as a greater charge can be M6 THE PROSPECTOR'S HANDBOOK. used at once than in a scorifier, the scorification process ia however, the usual one for ordinary ores. Assay of Gold and Silver Ores by Scorification :-~ Charge Finely powdered ore . 50 grains. ^Granulated lead 5001000 Borax * . 5 ,> Half the lead should be mixed with the powdered ore and placed in the scorifier ; the other half should be spread over this, and the borax on the top. The scorifier may then be placed in the muffle and the door closed until fusion is complete. Then the door may be partly opened and the temperature raised until the surface is covered with litharge, the whole time being about half an hour. The scorifier can then be taken out by the tongs and the contents carefully poured out into an iron cup or mould. When cool, the button of lead (which contains the gold and silver) should be detached from the slag, cleaned by hammering, and then, in the shape of a cube, is ready for cupellation. If Fusion in a Crucible be desirable, the following formulae are to be recommended : For ore, chiefly of rock Charge Ore . . . . 100 to 500 grains. Eedlead . . . . 500 Charcoal powder . 20 to 25 Carbonate of soda and borax 500 together The more quartz in the ore, the more carbonate of soda should be used; the more iron and other metallic bases, * Lead used in assaying should always be, in the first instance, cupelled, in order to find out whether it contains any silver mixed with it, which it usually does. The number of parts of granulated lead used varies according to the nature of the ore. Comparatively pure lead can be obtained by heating litharge or red lead with afeth the weight of charcoal. Even then the lead ought to be assayed for silver before using it in the cupellation process. Character of ore. Quartz. Galena. Arsenical, antimonial, iron copper pyrites ores. Parts test lead. 8 6 1016 Borax. Jthto 1. Jth to itb CUPELLING. 117 the more borax. The ingredients should be well mixed together and a little borax placed on the top. The crucible should be heated, though not too rapidly at first, until the contents are quite liquid. This will take about twenty minutes. After which it may be removed and the contents poured into the iron mould. When cool, the lead button should be detached from the slag, cleaned, and beaten into the shape of a cube ; it is then ready for cupellation. Fusion for silver and gold bearing copper ores and sulphides. Weigh the ore and roast it before fusion is commenced : Charge Ore . . . 100 to 500 grains. Kedlead . V . 1000 Charcoal powder . . 35 Carbonate of soda 200 to 3000 Borax .'' . . 150 to 300 Cupelling. While the muffle is in the process of heating, place the empty cupel (to make which see page 119) inside, and when the proper temperature of the furnace is reached, known by the cherry-red colour, gently, by means of the cupel-tongs, place the lead button (containing the gold and silver) obtained from the scorification or " fusion in the crucible" method into the concave hollow of the bone-ash cupel. Close the door of the muffle until the temperature of the fused metal is the same as that of the muffle. The behaviour of the assay can be observed through a slit at the side or top of the door. The assay must not be allowed to "freeze" ("freezing" is known by the fumes ascending right to the top of the muffle), nor must it be too hot (being too hot is known by the fumes scarcely rising at all, and the outline of the cupel being indistinct). If inclined to " freeze," a piece of charcoal may be put into the muffle to increase the heat, and the fire stirred. When the proper temperature is attained, the fumes from the cupel should reach about half-way up the height of the muffle, the cupel should be red, and the metal very luminous, while a stream of fused matter circulates about on the surface of the molten n8 THE PROSPECTOR'S HANDBOOK. liquid. The button gradually becomes more convex, and at last a mirror-like speck of bright silver or gold, or both, is left. The cupel should then be gradually drawn by means of the cupel tongs to the muffle door, so that the metal may not " spit," which it might do were the cupel to be too suddenly cooled in the cold air. In form the little button should, if a proper one, be well rounded, crystalline below, and easily detached from the cupel. As the button may contain both silver and gold, it should, after being cleaned by brushing with a paint brush and weighed, be removed and subjected to the action of nitric acid, in order that the silver may be dissolved and the gold left in the form of a dark powder ; after this the gold may be weighed, and the original weight of the button, minus the weight of the gold, will represent that of the silver. N.B. To separate the two metals in the button, place the button in a test tube with about ten times its weight in nitric acid (dilute), and boil for about a quarter of an hour ; the silver will be dissolved and the gold left. The liquid should be decanted, a little pure nitric acid poured on the gold powder to make sure that no silver remains, and the liquid poured off and the gold washed and dried. If the appearance of the button suggests that it is rich in gold, some silver must be fused with it before acid is poured on, as unless there be three times the amount of silver as gold, the " parting," as the above process is called, will be incomplete. Indications of the presence of metals in the ore known by cupel stains : Antimony pale yellow to brownish red scoria; some- times the cupel cracks. Arsenic White or pale yellow scoria. Cobalt dark green scoria and greenish stain. Copper green or grej^, dark red or brown. Iron dark red brown. Lead straw or orange colour. Manganese dark bluish black stain. Nickel greenish stain; scoria, dark green. Palladium and Platinum greenish stain ; the button will be very crystalline. Tin grey scoria ; tin produces " freezing." Zinc yellow on cupel ; the cupel is corroded. BONE- ASH CUPELS. 119 To prepare Bone-ash Cupels. The ash of burnt bones (that of the sheep or horse is preferable) should, in not too fine nor too coarse a state, be mixed with water (about an ounce of water to a pound of bone ash), so that it may, when of the proper consistency, adhere together when pressed, although not stick to the fingers. Places metal disc a coin if it fits well into the bottom of the cupel mould, and then fill the cavity with bone-ash ; place the hammer with the convex base on the top of the ash and give it a smart blow by a mallet or other hammer. The cupel can then, by means of the finger, be pushed uppermost and out of the mould. Assay for certain Metals other than Gold or Silver. To find the amount of lead in Galena, the usual lead ore. Charge powdered ore, two or three times the weight of carbonate of soda, three iron nails (tenpenny) placed in the top for taking up the sulphur, and a cover of salt or borax. The assay may be conducted in a muffle or other furnace. i^ The crucible two-thirds full of ore and fluxes should be heated to redness, and the temperature gradually raised until the operation is finished, which will be in about twenty or twenty-five minuiesr-^ The contents of the crucible are to be poured into a mould, and, when cool, the lead button separated from the slag. Weight of button ., AA , , TTT . & , 7 = x 100 = percentage of metal. vV eight of ore sample As galena always contains more or less silver, the resulting button ought to be assayed for the precious metal in the cupel. As a cupel does not conveniently absorb much more than its own weight of lead, the button may have to be divided into two or more portions, and each of these cupelled separately. Galena may be roughly assayed for lead by placing the powdered ore, without fluxes, in an iron dish, and exposing it to the heat of a blacksmith's forge. 120 THE PROSPECTOR'S HANDBOOK. To assay Copper ores by the crucible method, includ- ing the refining process, requires much practice, and for this reason the " wet assay ' ; is the more suitable for obtaining an approximate estimation of the amount of metal in a copper ore. Assay of Tin Ore. If the ore be poor, it ought to be concentrated, the vein- stuff being got rid of as much as possible. If mixed with iron or copper pyrites, it ought to be calcined or else treated with acids. One method is, as in Cornwall, to mix the ore with one-fifth of its weight of anthracite coal or charcoal, and to expose it in a crucible to a great heat for about twenty minutes. The contents are then poured out into an iron mould, and the slag carefully examined for buttons. Another method is to mix 100 grains of the ere with six times its weight of cyanide of potassium, and expose the mixture to the heat of a good fire for twenty minutes. The contents are allowed to cool, and afterwards broken to remove the slag. The buttons are then weighed. To assay Mercury ores, see MERCURY, Chapter V. Antimony. To determine the amount of antimony in an ore containing sulphide of antimony and more or less vein- stuff :~ Place about 2,000 or more grains of broken-up ore in a crucible, the bottom of which is perforated, and the hole in which is partially closed by a small piece of charcoal. Now fix the bottom of this crucible into the mouth of another crucible, so as to be about half-way down its depth. Then lute* the lid and also the joint between the two crucibles with fireclay and sand. By placing the lower crucible under the furnace bars and the upper one above, the heat of the furnace will cause the sulphide of antimony, which fuses at a red heat, to collect in the lower crucible, while the quartz and other matter will remain in the upper one. The operation should take about an hour and a half. * A dough of fresh fireclay and ground firebricks is a good lute. WET ASSAYS. 121 When pure, sulphide of antimony contains a little more than 70 per cent, of metaL WET ASSAYS. Gold. Powder about half an ounce of ore. Add four times its weight in a mixture of 4 parts hydrochloric and 1 part nitric acid, in an evaporating dish or other apparatus. Evaporate the decanted solution to dryness, hydrochloric acid being added as evaporation proceeds. Add sulphate of iron, dissolved in water, to the gold solution, both being previously warmed. The gold is precipitated as a brown powder. Filter the solution and weigh the dry precipitate. This method, however, is not to be recommended so much as the dry assay. Silver. Dissolve the powdered ore in nitric acid, and throw down the chloride of silver precipitate by adding a solution of common salt or else hydrochloric acid.* If chloride of lead and mercurous chloride are absent, tjie solution may be decanted or filtered, and the chloride of silver weighed : three-quarters of the weight very nearly represents pure silver. Or else the chloride of silver may be fused and the metallic silver collected and weighed. Lead- Place the powdered ore in a porcelain dish or other con- venient and suitable apparatus, and thoroughly dissolve it in strong nitric acid by heat until the residue is nearly white and red fumes cease to be given off. Add a few drops of sulphuric acid and evaporate to dryness ; then add water, and filter. As silica and certain sulphates may be in the residue, boil it along with carbonate of soda for about forty minutes. Filter. Dissolve the residue carbonate of lead, &c. in acetic acid. Add a little sulphuric acid to the * Ammonia added to the precipitate would dissolve the chloride of silver, would blacken the mercurous chloride, and would not alter the chloride of lead. 122 THE PROSPECTOR'S HANDBOOK. solution. Filter or decant the solution. The residue sulphate of lead nearly represents 68 per cent, of metallic lead. Copper. The most accurate method of determining the amount of copper in an ore is to thoroughly dissolve the ore in acid, then to add ammonia until a blue colour is obtained, and then to drop from a graduated burette a standard solu- tion of cyanide of potassium until the solution has the colour taken out of it. Number of markings on burette : present reading : : known strength of solution : x where x is the number of grains of copper in the weighed portion of the ore. X 100 = percentage of copper in the ore. weight of ore The burette method, like the dry assay, requires great care in order to insure accuracy, and might mislead one who has not studied and practised it, as certain metals other than copper may sadly affect the results. On this account there is no occasion for explaining the process in detail, as the prospector will find the following method comparatively simple. Take finely powdered ore, say 25 grains, drive off sulphur, &C..J by roasting (q.v.) in a porcelain dish. Dissolve by heating in nitric acid. Add a little sulphuric acid and evaporate to dryness. Dilute in water and pour the solution into a basin. If well polished sheet or other iron be placed in it, and left for an hour or so, the metallic copper will form on its surface, and by means of a feather may be rubbed off and weighed. Or else (to avoid roasting). Moisten the powdered ore in sulphuric acid, and add nitric acid. Let it be thus heated for about an hour or so, and let nitric acid be constantly added during the operation. Add hydrochloric acid to get rid of nitric acid, which may be judged by absence of chlorine smells. Dilute with water and obtain copper on the inserted iron as before. To see that all the copper has been properly deposited, dip the polished point of a knife- IRON ROASTING. blade into the solution ; if it has not, a film of copper will be left on the knife. Weight of copper .. Q~ _ percentage of copper Weight of ore sample m the ore. Iron, To assay an iron ore by the wet method, the standard solution of bichromate of potash is, by means of a graduated burette, added to the iron solution (the powdered ore dis- solved in hydrochloric acid) ; but like the other burette assays, this requires so much practice in order to secure reliable results, that there is no occasion to enter into details concerning it. The prospector will rarely require to know the exact amount of iron in an ore, and his own sense will perhaps guide him nearly as well as an assay, as great quantity and good quality are both necessary to make an iron ore payable. Roasting. In roasting the powdered ore much care is necessary in order that the sulphur, &c., may be expelled. The powdered ore placed in an open and shallow vessel, if possible, should be exposed to a low heat at first, and after a time the tempera- ture may be raised. During the operation free access of air is requisite, and the ore must be constantly stirred by means of an iron wire bent at one end, or other suitable apparatus, so as to prevent clotting. When fumes cease to be given off the operation is finished, about a quarter of an hour being the usual time necessary. Mechanical Assay of Ores. This is performed by crushing the ore and subjecting it to the action of water. If the powdered ore be subjected to the action of water running on an inclined plane or trough with a slope, the heavier particles of metals may be caught up in their descent by means of thin boards (riffles) fastened across the trough. Rough hides, with the hair upwards, may be used to intercept the heavier portions. To " pan " gold, see GOLD, Chap. V. CHAPTER X. TREATMENT OF OMES. Metallurgical treatment. Copper from copper pyrites and othe/ sul- phides. Lead from galena. Treatment of silver-bearing ores. Gold from lodes and deposits. Concentration of ore. IN the laboratory metals are obtained from minerals by either the wet or dry process, as briefly referred to in Chap. IX. If a mineral be dissolved in an acid or acids (N.B. Chloride of silver, tinstone, &c., are, however, nearly insoluble in acids), and reagents added, precipitates result; and from these the metals can, by fusion or otherwise, be obtained ; or, by the addition of certain metals to certain of the solu- tions, other metals can be precipitated : Iron precipitates lead ; Iron or zinc precipitates copper ; Copper, zinc, iron, lead precipitate mercury ; &c., &c. A few of the fusion methods have already been described \ but for the treatment of ores on a large scale many of the processes adopted in the laboratory are too costly, and, for this reason, though the principles of extraction may be the same, economy is of the utmost importance. The appa- ratus employed must be considered with regard to its original price, durability, efficiency, portability (in some instances), utility with respect to its being a labour-saving apparatus, and as a means of reducing the price and quantity of fuel, fluxes, and other requisites to a minimum. The cheapest fluxes, such as limestone (not, however, cheap in some countries where freightage is expensive), and com- paratively cheap chemicals have to be used where expen- sive substitutes would he out of the question. So, toc s TREATMENT OF ORES. 125 where fuel or water is absent from the immediate neighbour- hood of a mine, or when the locality is at a distance from civilisation, there are many points of importance which arise when the adoption of any particular p]ant or process has to be decided upon. A very great deal of thought has for many years, and is now, being bestowed in finding out more effectual and cheaper ways of dealing with silver and gold- bearing ores. Many a mine has to be closed on account of bad management, of its too great working expenses, or due to inability of a process to secure all the valuable metal in the ore. Certain it is that in different parts of the world, such as Western America, South Africa, &c., there is an immense quantity of what to-day is called low-grade ore, which, under favourable circumstances, at a future date, may be turned to profitable account; and which now might be worked if only the cost of treatment per ton of ore could be reduced by a few shillings, and which, so far as quantity and average quality are concerned, might be more lasting than many of the high-grade ore-bearing mines, which not unfrequently are " patchy." It is not the place here to lengthily describe the different processes by which the various metals are extracted from their ores; for in- stance, that of obtaining iron from its oxides by means of carbon, carbon monoxide, hydrogen, &c. ; or how the car- bonates have sometimes, in the first instance, to be calcined to reduce them to the state of oxides ; or of obtaining zinc from the sulphide by roasting, heating with carbonaceous matter, and by distillation ; or of mercury (from cinnabar) by heating in air, or with lime, or iron oxide, and distilla- tion ; or of obtaining antimony from its sulphide by means of scrap iron, &c. At the same time the prospector may derive some interest, if not benefit, by knowing a few of the principles which, practically applied, are dealt with in metallurgy. The various methods undergo much alteration and modifi- cation in not a very long space of time. As an example of this may be cited that of aluminium. The sodium process of not long ago has been quite replaced by electrical methods, which have very greatly reduced the price of the metal. So it is impossible, just as it is unwise to state which is 26 THE PROSPECTOR'S HANDBOOK. the best one for treating any particular kind of metalliferous ore. Besides, that which suits an ore in one locality may be quite unsuitable, for reasons already explained, for that in another. Perhaps the best way to approach this subject of metal- lurgy is to consider one of the methods which may be rightly termed complex, viz., extraction of copper from cop- per pyrites. Copper from Copper Pyrites and other Sulphides. Calcination (to get rid of sulphur, arsenic, &c.) ; fusion with " metal slag " (containing a proportion of silica, iron oxide, &c.) and other copper ores, in order to obtain a regu- lus or matte (which contains sulphides of copper and iron) ; calcination of the crushed regulus ; fusion of this to get rid of iron (in this process copper oxide or carbonate is added, also certain slags which contain silica, &c.) ; roasting of the regulus to obtain blistered copper. This process depends on the fact that copper possesses for sulphur a greater affinity than iron does. Thus when a mixture of the oxides and sulphides of iron and copper are fused together the iron combines with the oxygen and the copper with the sulphur, a mixed sulphide of the two metals resulting if there is not sufficient oxygen present to com- bine with the whole of the iron. The iron oxide so pro- duced can be slagged away by the aid of silica, and the cop- per collected, more or less free from iron, in the form of a fused sulphide regulus. There are two main methods of copper smelting the reverberatory and the blast furnace methods. In the for- mer the copper sulphide produced in the above manner is partially roasted to oxide, and the oxide so formed allowed to react on the residual sulphide, metallic copper being the result. In the other, the nearly pure sulphide " white " or " pimple metal " is roasted almost completely to oxide, which is then reduced by the aid of carbon in some form. The wet methods are mainly two. In the one the copper sulphide is roasted to sulphate, which can then be extracted with water, the copper being afterwards precipitated by TREATMENT OF SILVER-BEARING ORES. I*? iron. In the other, the oxide ore, containing some sulphur, is roasted with common salt, cupric chloride resulting, which can be leached out by the addition of water, the residues being subsequently extracted by the hydrochloric acid, which forms a bye product of this process. To extract lead from galena, in a manner akin to that referred to in assaying, is a comparatively simple process. To do so, however, in the most economical manner, many operations and much plant may be necessary, the very lead fumes being in some instances turned to account. It must be remembered that galena contains silver, not always in such quantity as to demand much consideration; but frequently the reverse : indeed, often a galena ore may be only valuable for its silver. As the lead obtained from the smelting furnace contains also the silver (and gold), the cupellation process, the principle of which has been men- tioned in page 117, or other methods are made use of to obtain the precious metals. In the Pattinson process, with the various ladlings from one pot to another, the principle involved is that when a lead-silver alloy is allowed to cool slowly, crystals of lead separate out, and these are very poor in silver, this metal becoming concentrated in the residual " mother liquid." In the Parkes method, which now is much made use of, metallic zinc is stirred into the lead, and, this cooling down, the zinc rises to the top and solidifies. It is then found to contain both the silver and gold originally in the lead. Treatment of Silver-bearing Ores. The extraction of silver from certain lead ore has been referred to in the foregoing remarks. When the ore is a carbonate, the ore can be smelted with oxide of iron and limestone to obtain all the lead with the silver. Some silver-bearing ores containing sulphides are treated after the manner referred to in the description of the treat- ment of copper ores, so that there may be obtained a regulus, which may either be roasted direct to form sulphate, the silver sulphate being washed out with water (Ziervogel's method). In the Augustin method, the ore is roasted with salt, the silver chloride extracted by brine, THE PROSPECTOR'S HANDBOOK. and the silver thrown down from the solution by some metals, such as copper. In the Von Patera method, so largely used in practice, after roasting with salt, the ore is leached with a weak solution of sodium hyposulphite, the silver being afterwards thrown down from this solution by a soluble sulphide. In the process whereby the silver-bearing ore is roasted, and a sulphate of silver dissolved by water and the silver precipitated by means of copper, the residue may have to be smelted with addition of gold-bearing pyrites, to obtain a matte in which the gold and silver are retained. In the Mexican process, the sorted silver ore (native silver, sulphide, and chloride of silver) is placed in heaps with common salt, for a while, then ground with magistral (derived from roasted iron-and -copper sulphides) and mercury. There is no occasion, however, to extend this subject, suffice it to say that the foregoing methods will give an idea as to some of the principles involved. The following table will show certain conditions under which the Pan amalgamation and Hyposulphite leaching means are adopted : Pan amalgamation { J ^ftefroasting with salt. ' a Direct or after roasting with salt. Hyposulphite leaching \ ft Using a mixed solution of copper and sodium hypo- sulphite (Kussell's process.) Gold from deposits and lodes. When the gold is " free " in alluvial deposits, sluices, cradles, &c., washing down of matter by hydraulicing, &c., are made use of. When the gold is free in lode matter, the ore is usually stamped very finely, and amalgamation with mercury, as the gold, &c., is washed down inclined planes, &c., the amalgam being eventually squeezed through chamois leather, blankets, canvas, &c., to get rid of the superfluous mercury, GOLD FROM DEPOSITS AND LODES. 129 and the residual mercury with gold being then retorted to leave only the gold behind. Auriferous ore with sulphides may firstly be roasted and then treated with mercury. At the same time such a pro- cedure is not always economically satisfactory, especially when there is a coating of any foreign metallic compound around the gold. The following summary will afford an idea of some of the methods applicable : r a Chlorination process.* ft Cyanide Pyrites and refractory I 7 Amalgamation after roasting. <.! s o Concentration in metallic materials. iij.ii* lead, metallic copper, or in a mixed regulus or in iron sulphide. In the Chlorination process, chlorine gas, which has a great affinity for gold, is generated and unites with the gold to form a chloride of gold, which is then dissolved by water, and the precious metal precipitate3 by means of sulphate of iron or other agent. There is no occasion to enter fully into an account of the process, suffice it to know that whether black oxide of manganese with salt and sulphuric acid, or chloride of lime and sulphuric acid, or chloride of lime with another agent, not a free acid, sea salt or salt water and lime, salt and caustic lime, are used, the object is to attain the most efficient way of obtaining the gold as a chloride. In the cyanide process, much used in the Transvaal, &c., for obtaining the gold from tailings, a solution of cyanide of potassium is used for the purpose of seizing the gold, to form a cyanide of gold compound, which is passed over metallic zinc, or otherwise treated, whereby the gold is deposited. It must be borne in mind, that any new chemical process, before being used, should be well investigated as to its suitability. One may not be advisable, if the gold is in too * This process is much used in the Transvaal for the treatment of mlphide concentrates. 130 THE PROSPECTOR'S HANDBOOK. coarse a state, or when the presence of another metal or metallic compound, such, for instance, as copper, might interfere with the operation. In such a case, the agent might attack such ingredient of the ore, rather than the gold, unless means were adopted to obviate this. A thorough analysis of samples of ore should be always made, and the merits and demerits of a proposed process thoroughly investigated by someone of experience, before any particular "plant" is constructed, or any method adopted for the treatment of the ore in a mine. Sometimes more than one process is advisable in the treatment of ore ; for example, as often is the case in the Transvaal, the crushed quartz may be first subjected to the amalgamation process, the sulphide concentrates to the chlorination, and the tailings to the cyanide. Especially is this the case where such minerals as antimony, sulphide, zinc blende, and other sulphides, are present in quantity. Very frequently such ores, though they may assay fairly well for gold and silver, cannot be smelted profitably, especially in out-of-the-way districts, where everything freightage, fluxes, labour, &c. is expensive. In the foregoing remarks no notice of that which fre- quently constitutes one of the chief elements of success in the prosperity of a mine, viz. : concentration, has been taken. The concentration may be applied, for instance, in the collection of the heavier portions of the ore, crushed finely or coarsely, and is applicable not only to the ore before any other operations take place, but also to the " tailings." It is effected sometimes by one machine, sometimes by several, classification of the ore being made with regard to size or weight of the small particles of pieces of ore. Just as the heavy grains sink to the bottom of the gold- washer's "pan," so, on a larger scale, do they in the " toss- ing tub," the "dolly," or "kieve." So if mixed, finely divided ore or sand, containing, for example, all sorts of minerals, such as gold, iron compounds, &c., copper pyrites and earthy matter or quartz, be shaken together with water, the lighter matter settles down above the " heavier." CONCENTRATION. 131 In the ordinary " jigging" apparatus a sieve containing broken or crushed ore is worked up and down in water, or has water pushed through from underneath, and the heavier parts which do not fall through the meshes, follow the same law as the above. The essential rule to follow is that the ore must first of all be carefully sized by means of revolving riddles or " trommels," and that ore of only a certain definite size or "mesh" should be supplied to each machine. Another plan of concentration is that of allowing running water to wash the ore along an inclined plane, as in the ordinary amalgamation tables, or in the " Broad Tom " or " Long Tom " sluice (natural or artificial) ; and the same principle that the lighter portions are washed farther down than the heavier ones which remain near the top applies to the " huddle " for treating slimes or finely divided ore. In the simplest form of "buddle" the ore is passed through a vertical passage on to the apex of a cone with slightly inclined sides, the heavier matter settling near the apex. It is unnecessary to describe the many 'Various kinds of concentrators which have been or are being used. Mention, however, may be made of the well-known Hendy's concen- trator, in which the oscillating shallow pan is constructed in a specially designed curve towards the centre. In this apparatus the heaviest portions sink to the bottom and the lighter flow through an outlet in the centre. In the Frue Vanner, a shaking motion is imparted, the finely divided matter being placed on the upper end of a revolving band. In "percussion" tables the action of water and percussion causes the heavier matter to bo retained at the head of the table and the lighter farther removed. To classify mineral matter according to size, the ordinary sieve, trommels (revolving sieves, cylindrical, conical, single, or continuous), are much used for coarsely broken ore. There are other classifiers in which the varying velocity of the grains in water, &c., are made use of, and in some concentrators atmospheric assistance and gravitation, and also centrifugal force, play a part. t$\a THE PROSPECTOR'S HANDBOOK. The usual scheme of concentration adopted is, first of all, to crush the mineral by means of a rock-breaker to the size of, say, macadam. The rich portions of ore can then be picked out on a picking table, and put on one side ready for market. At the same time the sterile or waste stone can also be sorted out and rejected. The remainder then goes on to the mill. If it is a lead, zinc, or copper ore, the mineral is crushed between revolving rolls, sized in trommels, and then separated in jiggers. The fine ore or slimes is carried on to hydraulic separators or " Spitzkasten," where the bulk of the water is got rid of, and then the ore is treated on some form of concen- trating table, of which there are many good ones on the market. In the case of gold ores, after the preliminary sorting, the mineral goes to the stamps direct, where it is crushed to powder and mixed with water. The pulp, as it is then called, passes over copper plates coated with mercury, called amalgamated plates. Here the free gold is caught, and afterwards scraped off as an amalgam of gold and mercury. The latter is driven off by distillation. The gold which is not free is called refractory, and the slimes from the plates are collected and treated, first possibly by concentration tables, and finally by the cyanide or chlorination processes, which are chemical, and dissolve out the gold for subsequent precipitation. Concentration, amalgamation, and cyaniding are special processes, and should be studied apart, in the books devoted to these subjects. In addition, for magnetic or slightly magnetic minerals, there are magnetic separators, which prove highly successful in the treatment of these special ores, while of recent date the El more Vacuum Oil Process has been successful in dealing with mixed ores. The ordinary arrangement of a mill for the treatment of an ore carrying lead (galena) and zinc (blende) is, in general terms, as follows : The crude ore from the mine is delivered by tram or aerial ropeway into a large hopper above the mill. This hopper should, if possible, be sufficient to contain a day or two's supply of ore for the mill in case of breakdown CONCENTRATION. in the mine or tramway, so as to avoid a stoppage of the machinery. From the hopper the ore is fed into a rock- breaker, below which is a trommel. The rough broken ore passes on direct to a picking belt, the fine going to the mill. The picking belt, or rotary table, may be of any desired size, so as to enable a careful hand-sorting of the ore to be made. The rich mineral is sorted out and bagged, the mixed ore passes on to the roller crushers of the mill, or may be again broken by a rock-breaker and sorted on another picking table, en route to the rollers, while the sterile ore is thrown away. The amount of ore to be treated in the mill is thus materially reduced both by the rich ore and steriles being picked out. The mixed ore is then ground between roller crushers, taking care to avoid making slimes as far as possible. After leaving the rolls the mineral passes through a set of revolving sizing trommels, or sieves. Each of these trommels feeds a separate jig, with a carefully sized minors:! - The jiggers separate the mineral into rich ore, mid- dlings, and waste. The middlings are re-ground and treated on separate jiggers. The waste is thrown away. The sands and slimes too fine for classification by means of trommels flow over hydraulic classifiers, which feed fine high-speed jiggers with sands ; the slimes pass on to large Spitzkasten, where the bulk of the water is got rid of, and the fine mineral passes on to some form of con- centration table for final treatment and separation. These tables, like the jiggers, separate the ore into rich, mid- dlings, and waste. The middlings, if rich enough in mineral, can be re-treated. The design and arrangement of the details of an auto- matic concentrating mill demand much careful study and trained skill, with numerous experimental tests on the actual ore, before a final decision is arrived at. Other- wise, as has too frequently been the case, unsuitable machinery has been sent out at enormous expense of money and time, with grave, if not ruinous, financial loss to the Company. CHAPTER XI. SURVEYING. To calculate areas. To find the distance from an inaccessible place. To solve problems in connection with adits, shafts, lodes oi a mine. Position of a shaft with regard to a lode. IN ordinary survej r ing, a Gunter's chain 66 feet long, and consisting of 100 links, each tenth one of which has some distinguishing mark attached, is very frequently used for measuring lengths. When the number of square links in a piece of ground is known, this divided by 100,000 (the division being performed so easily by striking off five figures from the right hand side to the left) will represent the number of acres in the area. To find how many acres there are in a rectangular piece of ground, multiply the length in links by the breadth in links, and divide the result by 100,000. Example. Find the area in acres of a rectangular piece of ground, the length of which is 1,225 links (that is, 12 chains and 25 links), and the breadth 150 links (that is, one chain and a half). 12 chains 26 links. AREA. Number of acres = FIG. 60. 1225 x 150 100000 1-83750 acres. CALCULATION OF AREAS. 133 The number of roods in the -83750 of an acre may be found by multiplying this by 4 and dividing by 100,000 ; the number of poles, by multiplying the remaining decimal by 40 and dividing by 100,000. Thus : 83750 > 4 3-35000 40 14-00000 = 3 roods 14 poles. Therefore the whole area = 1 acre, 3 roods, 14 poles. To find the area of a triangular piece of land, find the area of the triangle in square links and divide by 100,000. To find the area of a triangle in square links, multiply the length of the base by the length of the perpendicular from the opposite corner to the base and divide the result by 2. Example. Find the area of the piece of land ABC. Set up poles at A B c. Measure B c. Travel from B towards c until a point D is reached where the line A D seems to be at right- angles to B c. Measure A D. Suppose B C = 1200 links ; A D = 168 links. Area in acres = FIG. 61. 1200 X 161 134 THE PROSPECTORS HANDBOOK. which worked out as in the last example will give 1 acre, 3 roods, 29 &c. poles. To find the area of a piece of land indicated by the figure A D c B. Measure B D. Then find areas of triangles A D B, B D c, as in the last example. The whole area equals the area of the triangle A D B added to that of the triangle B D c. Similarly, to find the area of a tract of land ABODE. c FIG. 63. The whole area equals the area of the triangle ODE, plus that of A c E, plus that of A B c. LENGTH OF A SHAFT OR ADIT. 135 In any of the above calculations, should the measurement be by yards and feet, the number of square yards in the land divided by 4,840 will give the number of acres. (See Measures, APPENDIX.) To find the distance between the points where one is in- accessible from the other for instance, on the other side of a river. Eequired the distance between B and A. FIG. 64 Pace off from B, at right-angles to the direction B A, a distance B E ; then continue pacing off a distance E c, so that E c may be some even fraction of B E (say one-fourth or one-eighth). Proceed, at right angles to c B, along c D until a point D is reached, where DBA seem in one and the same straight line. Then : Required length A B = CD X EB EC Very frequently the prospector may wish to form some idea of the length of an adit necessary to meet a perpen- dicular shaft sunk from a certain known spot, or the length of a vertical shaft necessary to be sunk to meet an adit driven in from a certain point. To solve such problems (as well as many others in connection with surveying) a very limited knowledge of the properties of a right-angled 136 THE PROSPECTOR'S HANDBOOK. triangle, together with a Table of Sines (see Appendix), may prove useful. Let x A B c be a right-angled triangle. (i.) Perpendicular A B equals length A C multiplied by sin c. Base B c ,, AC sin a. Let A c represent two points on a hill-side, from which respectively a shaft, A B, is to be sunk, and an adit, c B, driven. Let B be the point where they may be supposed to meet. Measure length A c, and suppose it to be 200 feet. Measure either the vertical angle a (which is really 90- the dip of the hill- side) or else the angle c, which is the dip. Let a 50 30' ; and c = 39 30'. FIG. 65. Then by (i.) Perpendicular A B equals 200 feet x sin. 39 30'. B c 200 X sin. 50 30'. Now by Table of Sines, sin. 39 30' is -6361, and, sin. 50 30' is -7716. Therefore : perp. A B equals 200 feet x '6361. base B c equals 200 feet x '7716. That is : perp. A B is 127*22 feet, base B c is 154-32 feet. The length of the shaft is 127 '22 feet, and that of the adit 154-32 feet. LENGTH OF A SHAFT OR ADIT. 137 Should the hill-side A o E G be irregular, such as in Figure 66. Then A c, c E, E G, should be measured from convenient points, A, C, E, G. To find the length of shaft A o, find the lengths of A B, C D, E F, as in the last example. The whole length A equals the sum of the lengths A B, C D, E r. In the same way, the length of the adit G equals the sum of the lengths B C, D E, F G. Also,, if any two sides of the right-angled triangle ABC are known, the third side can also be found without using the Table of Sines. FIG. 66. Fia. 66A. For A C square root of (A B 2 + B c 2 ) AB= (AC 2 -BC*) B C = (A C 2 - A B) Thus, supposing A c = 100 feet, A B 80 feet, B c would equal the square root of 100 x 100 - 80 X 80, that is, square root of 3600, that is, 60 feet. If it is required to know how deep a shaft will have to 138 THE PROSPECTOR'S HANDBOOK. be sunk, or how long an adit driven, to strike a lode whose inclination to the hill-side is known, certain properties belonging to any triangle and a reference to the Table of Sines will suffice Let A B c be a triangle where A c repre- sents the hill-side, A B the lode, c B an adit. Let the length A c be known, and also the angles a and c (and therefore the angle b, which is 180 the sum of angles a and c). Suppose it be required to know how far the adit will have to be driven to cut the lode and also the depth of the lode. FIG. 67. By a property of a triangle, A c X sin. a Length B c = -^-jr . , , A c x sin. c Also, length A B = -. r sin. o The question, Where ought a shaft to be sunk 1 has to be decided on as soon as development work is contem- plated ; and though the question depends in some measure on the nature of the country, rock, and other considera- tions, the following general hints may be useful. If the lode dips in the same direction as the hill-side, the shaft ought to be as in Fig. 68, A. If the lode dips contrary to the slope of the hill, then either the shaft should be sunk on the lode or higher up than the outcrop, or else below the outcrop, so that cross- cuts can be .driven (Fig. 68, B). POSITION OF A SHAFT. 139 In certain cases, when the lode lies at a considerable inclination from the perpendicular, the shaft should be sunk along the lode rather. than in a vertical direction. Adit levels, which facilitate the proper working of a mine, also help to drain it; and, in consequence, they FIG. 68. A. 6, Lode, a, Shaft. B. a, c, Lode. t> d, Perpendicular shafts, c, Where shaft intersects the lode, e, e, Crosscuts. should be driven at as low a level in the valley as possible, and with a very gentle slope, just sufficient to enable the water to flow away. With regard to the size of shafts and adits, the dimen- sions of the former vary from 6 by 5 feet to 8 by 6 feet, while the engine shafts are usually 11, 12, or 13 feet by 140 THE PROSPECTOR'S HANDBOOK. 8 feet ; the adits are generally 7 or 6 feet in height, and 4 or 6 feet in width. FIG. 69. LODE WOKKED BY VERTICAL SHAFT. 1, Lode. 2, Shaft, 15 -120 fathoms crosscuts. 3, Productive strata. 4, Unpro- ductive strata. 5, Adit level. 6, Dressing sheds. KB The ore is more difficult to raise up a slanting shaft than a perpendicular one. APPENDIX. Weights and measures of England, France, &c. Weight of various rocks and metallic ores. Specific gravity of metals, metallic ores and rocks. Table of natural sines. Melting point of various metals. Table to find the number of ounces of metal to the ton of ore. Glossary of terms used in connection with prospecting, mining, mineralogy, assaying, &c. To find weight of ore fn a lode, and the value of a mine. WEIGHTS AND MEASURES. 3 barleycorns = 12 inches = 3 feet = 5i yards = 4 poles or 100 links i 10 chains = i 8 furlongs = i ENGLISH. Measures of Length. inch. foot. yard (36 inches). rod, pole, or perch (i6J feet). chain (22 yards or 66 feet.) furlong (220 yards). mile (1760 yards). A span = 9 inches ; a fathom = 6 feet ; a league = 3 miles. Surface Measure. 144 square inches 9 square feet 30^ square yards 1 6 poles (square) 40 poles 10 chains 640 acres square foot. square yard. pole, rod, or perch (square). chain (sq.) or 484 square yards. rood (sq.) or 1210 square yards. acre (4840 square yards). square mile. Solid Measure. 1728 cubic inches = i cubic foot. 27 cubic feet = i cubic yard. I42 THE PROSPECTOR'S HANDBOOK. Measures of Weight. Troy Measure (by which gold, silver, platinum, and precious stones are weighed, though diamonds are by the carat (150 carats = 480 grains). 24 grains ' i pennyweight. 20 pennyweights = i ounce ( 480 grains). 12 ounces = i pound (5760 grains). Avoirdupois Weight 1 6 drams = i ounce (437^ grains). 1 6 ounces = i pound (7000 grains). 14 pounds = i stone. 2 stone = i quarter. 4 quarters = i hundredweight (112 Ibs.). 20 hundredweight =. i ton (2240 Ibs.). A cubic foot of water = nearly 1000 ounces. Av. oz. = 43 7 1 grains. i gallon of water = 10 Ibs. Troy oz. = 480 grains. FRENCH. Measures of Length. Millimetre (i*W of a metre) = '03937 inches. Centimetre ( T fcr ) = -3937 Decimetre (-& ) = 3'937 Metre (unit of length) = 39*3708 ins. or 3-2809 ft. Decametre (10 metres) = 32-809 ft. or 10-9363 yds. Hectometre (100 metres) = 109 '3633 yards. Kilometre (1000 metres) = 1093-63 yds. or '6138 miles Myriametre (10000 metres) = 6-2138 miles). Measures of Surface. Centiare ( 3 K of an are or sq. metre) = 1-1960 sq. yds. Are (unit of surface) ( = 1 1 9' 6 33 sq. yds. or '0247 acres. Decare (10 ares) / = J T 96'033 sq. yds. or '2474 acres. Hectare (100 ares) j = ' I ^'^ 1- yds. I or 2*4736 acres. WEIGHTS AND MEASURES. 143 Solid Measure. Decistere (iV of a stere) = 3*5317 cubic feet. Stere (cubic metre) = 35-3 1 66 Decastere (10 steres) = 353* l6 5 8 > Measures of Weight. Milligramme (ycW of a gramme)= '0154 grains. Centigramme ( r ihr )= *i544 Decigramme (iV )= i*544 Gramme (unit of weight) = 15*44 Decagramme ( 10 grammes) 154-4 ( 3-2167 oz. Troy Hectogramme ( i oo grammes) = 1544 grs. J or ( 3'5 2 9i oz Av. Kilogramme (1000 grammes) = 32^ oz. or 2-2057 Ibs. Mynagramme (10000 grammes) = 22*057 Ibs. The French metrical system is adopted in most countries, including Spain. The following, however, may be of use in countries where Spanish is spoken : Measures of Length. 12 pimtos = i linea (-077 inch). 12 lineas = i pulgada (-927 inch). 6 pulgadas i sesma (5*564 inch). 2 sesmas = i pie ('9273 feet). 3 pie = i vara (2-782 feet). 4 varas = i estadal (in 26 feet). The legua = 8000 vara. Measures of Weight. 3 granos = i tomin (9*2 grains). 3 tomines = i adarme (27*7 grains). 2 adarmes = i ochava or dracma (55- 5 grains). & ochavas = i onza ('0634 Ibs, or 443*8 grains). 8 onzas = i marco ("5072 lb. a marcos = i libra (1-0144 144 THE PROSPECTOR'S HANDBOOK. WEIGHT OF VARIOUS ROCKS AND METALLIC ORES. Lbs. in I Cubic Foot. Antimony Sulphide . 281 25 Basalt . . . . 182 Chalk . 125 Clay (ordinary) . . 120 Coal Anthracite . 58*25 Bituminous . - * - -53 Cobalt Tin White * .. . 400 Copper Pyrites * > ."; . 259 '37 n Grey . * * 296*87 Red . * 375 Malachite o . ] . . 250 Flint . . . . . * . 162 Fluor Spar * . 196 * 2 5 Granite Grey Aberdeen v . . i6 7 Red . . . i6 5 Iron Pyrites . ; .... 3 Magnetic Ore . : . . 312 '5 Specular , . . .281 2 Brown Haematite L' ; * . . 225 Lead Sulphide (Galena) . . . 468-75 Limestone Lias . Magnesian * . . 145 Compact Mountain . .170 Manganese Binoxide . . A ... . 300 Marble . . . << Marl . Porphyry Quartz . < . < ^ . . . 166 Sand River . . , . . .118 Fine-grained , * * 95 Silver (Horn) . . ! m . 287 5 Slate . . 160 Syenite ... -, 164 SPECIFIC GRAVITY OP ORES. 14$ Lbs. in i Cubic Foot Tin Oxide . . 406*25 Sulphide , ' 268-75 Zinc Blende '. . % "..-"- 250 Calamine . . . 26875 THE SPECIFIC GRAVITY OF METALS, METAL LIC ORES, AND ROCKS. METALS. S.G. Platinum , . . . i6'o 21* Gold . . . . . 15*0 19-5 Mercury . . . I 13*5 ^ Lead .... . . ., n'35 Ir 5 Silver . ) . . ; . * io'i ii'i Copper . . . .:' . 8-5 8-9 Iron . . . . . , 7-3 77^ COMMON ORES OFTEN MET WITH IN GOLD AND SILVER BEARING VEINS. S.G. Galena , .~ : . . . 7*27-7 Iron Pyrites . . v ; . 4'S 5*2 Copper Pyrites ..... 4*0 4*3 Zinc Blende ... . . 37 4*2 METALLIC ORES. S.G. Silver Silver Glance . . . . 7*2 7-4 Ruby Silver (dark) . . . 5-7 5-9 ,, (light) . . . 5*5 5'6 Brittle Silver (Sulphide) . . 5*2 6-3 Horn Silver .... 5-5 5*6 Mercury Cinnabar .... 8'o 8*99 Tin Tinstone . . . . . 6-47-6 Pyrites . . ^--^r . 4*34*5 Copper Red or Ruby Copper . . 5*7 6-15 Grey .... . 5'5~ 5*8 Black Oxide f ^. . 5' 2 6 '3 Horseflesh Ore . ' . . 4*4 5 '5 Pyrites. . . . . 4'i 4*3 THE PROSPECTOR'S HANDBOOK. S.G. Copper Carbonate (Malachite) . , 3-5 4*1 Lead Sulphide (Galena) . . . 7-2 7-7 Carbonate (White Lead Ore) . 6-46-6 Zinc Calamine . . 4*0 4-5 Blende . . . . . 3-7 4-2 Iron Haematite . " . . 4-5 5*3 Magnetic Iron Ore . . 4-9 5-9 Brown Iron Ore , . . 3-6 4*0 Spathic . . . . . 3-73*9 Pyrites (Mundic) . . . 4*8 5-2 Antimony Grey (Sulphide) . . 4-5 4-7 Nickel Kupfernickel . . . 7-3 1-5 Noumeaite (New Caledonia) . . 2-27 Cobalt Tin white . . . .6-5-7-2 Glance . 6'o Pyrites . . . . . 4*8 5*0 Bloom . . . . 2*91 2-93 Earthy 3-1 53-29 Manganese Black Oxide . * . 4-7 5-0 Wad (Bog Manganese) . 2-0 4-6 Bismuth -Sulphide . . . . 6*4 6-6 Oxide . . . . -. 4 '3 MINERALS FORMING THE GANGUE OR MATRIX IN VEINS. S.G. Quartz .,..'.. 2-5 2-8 Fluor Spar ...... . 3-0 3-3 CalcSpar . . . . . . 2-52-8 Barytes . . . / . . 4-34-8 ROCKS OF COMMON OCCURRENCE. s.o. Granite ) Gneiss / ' V ' a< 4 '7 Mica Slate . -- . . 2*6 2*9 Syenite . . . 2-73-0 Greenstone Trap . . 2-7 3*0 Basalt ; . , . . 2-6 3-1 Porphyry . . , . 2-3 27 Talcose Slate , , . 2-62-8 Clay Slate (Killas) 2-5 2-8 NATURAL SINES. 147 Chloritic Slate . V Serpentine Limestone and Dolomite Sandstone . . Shale . V . S.G. 2-728 2-52-7 1-92-7 2-8 TABLE OF NATURAL SINES. 0' 10 20' 30' 40' 50' oooo 0029 0058 0087 0116 0145 1 0175 0204 0233 0262 0291 0320 2 0349 0378 0407 0436 0465 0494 3 0523 0552 0581 0610 0640 0669 4 0698 0727 0756 0785 0814 0843 5 0872 0901 -0929 0958 0987 1016 6 1045 ' 1074 1103 1132 1161 1190 7 1219 1248 1276 1305 1334 1363 8 1592 1421 1449 1478 1507 1536 9 1564 1593 1622 1650 1679 1708 10 -1736 -1765 1794 1822 1851 1880 ii' 1908 1937 1965 1994 2O22 2051 12 2079 2108 2136 2164 2193 2221 13 2250 2278 2306 2334 2363 2391 14 15 2419 2588 2447 2616 2476 2644 2504 2672 2532 270O 2560 2728 i6 2756 2784 2812 2840 2868 2896 17 2924 2952 2979 3007 3035 3062 1 8 3090 3118 '3*45 3173 32OI 3228 19 3256 3283 ;33" 3338 3365 '3393 no 3420 3448 ;352 3529 3557 21 3584 3611 3638 3692 3719 22 3746 '3773 3800 3827 3854 3881 23 3907 3934 3961 3987 4014 4041 24 4067 4094 4120 4147 HI73 4200 25 4226 4253 4279 4305 4331 4358 26 27 4384 4540 4410 4566 4436 4592 4462 4617 4488 H643 45H 4669 28 4695 4720 4746 4772 '4797 4823 29 4848 4874 4899 4924 4950 '4975 30 5000 5025 5050 5075 5100 5125 3 [ 5150 5175 5200 5225 5250 5275 32 5299 5324 5348 5373 5398 5422 33 5446 5471 5495 5519 5544 5568 34 5592 5616 5640 5664 5688 5712 35 5736 5760 5783 5807 5831 5854 36 5878 5901 5925 5948 5972 5995 37 6018 6041 6065 6088 6m 6134 38 6157 6180 6202 6225 6248 6271 39 6293 6316 6338 6361 6383 | -6406 148 THE PROSPECTORS HANDBOOK. 0' 10' 20' 30' 40' 50' 40 -6428 6450 6472 6494 6517 6539 41 6561 6583 6604 6626 6648 6670 42 6691 6713 6734 6756 6777 6799 43 6820 6841 6862 6884 6905 6926 44 6947 6967 6988 7009 7030 7050 45 7071 7092 7112 7133 7153 7173 46 7193 7214 7234 7254 7274 7294 47 73H 7333 '7353 7373 7392 7412 48 743i 7451 7470 7490 7509 7528 49 7547 7566 7585 7604 7623 7642 50 7660 7679 7698 7716 7735 '7753 5i . 777 i 7790 7808 7826 7844 7862 52 7880 7898 7916 7934 795i 7969 53 7986 8004 8021 8039 8056 8073 54 8090 8107 8124 8141 8158 8i75 55 -8192 8208 8225 8241 8258 8274 56 8290 8307 8323 8339 :8355 8371 57 8387 -8403 8418 8434 8450 8465 58 8480 8496 8511 8526 '8542 8557 59 8572 8587 8601 8616 8631 8646 60 8660 8675 8689 8704 8718 8732 61 8746 8760 8774 8788 8802 8816 62 8829 8843 8857 8870 8884 8897 63" 8910 8923 8936 8949 8962 8975 64 8988 9001 9013 9026 9038 9051 65 9063 9075 9088 9100 9112 9124 66 9135 9147 9159 9171 9182 9194 67 9205 9216 9228 9239 9250 9261 68 9272 9283 9293 9304 93i5 93 2 5 69 9336 9346 9356 . 9367 '9377 9387 70 '9397 9407 9417 9426 9436 9446 71 9455 9465 '9474 9483 9492 9502 72 95ii 9520 9528 9537 9546 '9555 73 9563 9572 9580 9588 9596 9605 74 9613 9621 9628 -9636 9644 9652 75 9659 9667 9674 9681 9689 9696 76 9703 9710 9717 9724 9730 '9737 77 '9744 9750 '9757 9763 9769 '9775 78 978i 9787 *9793 '9799 9805 9811 79 9816 9822 9827 9833 9838 9843 80 9848 9853 9858 9863 9868 9872 81 9877 9881 9886 9890 - -9894 9899 82 9903 9907 9911 9914 9918 9922 83 9925 9929 9932 9936 '9939 9942 84 "9945 9948 9951 '9954 '9957 '9959 85 9962 9964 9967 9969 9971 '9974 86 9976 9978 9980 998i 9983 9985 87 9986 9988 9989 9990 9992 '9993 88 9994 9995 9996 '9997 9997 9998 89 9998 '9999 '9999 '9999 I -0000 I -0000 MELTING POINT OF METALS. 149 MELTING POINT OF VARIOUS METALS. Antimony . . 1150 Fahrenheit. Copper . . ,.; . 1990 Gold ,' . . 2000 Iron (Cast) fc .-. . 2780 Lead V . . 617 Mercury . . ..' . -39 Silver . 1800 Tin . . 442 Zinc. 773 TABLE TO FIND THE NUMBER OF OUNCES TO THE TON OF ORE FROM THE WEIGHT OF BUTTON OB- TAINED BY CUPELLATION OR OTHER PROCESS. If i DO grains of ore yield of fine metal : grains, ooi oio i i One ton of ore will yield at same rate : oz. dwt. gr. 6 12 3 5 32 13 8 326 13 8 Ex. Suppose 200 grains of ore yield 27 grains of silver, how many ounces is this to the ton of similar ore ? ico grains will evidently yield 1*35 grains ; therefore, number of ounces to the ton oz. dwt. gr. oz. dwt. gr. oz. dwt. gr. = 326 13 8 + 3 X 32 U + 5 X 3 5* which, when worked out, is exactly 441 oz. Again, suppose 50 grains yielded -02 grains ; what is this to the ton? 100 grains will evidently yield -04 grains; therefore the number of ounces to the ton oz. dwt. gr. oz. dwt. gr. = 4X3 5 8=13 I * ISO THE PROSPECTOR'S HANDBOOK. To Find the Weight of Ore in a Lode, and Value of a Property. To find approximately the weight of a quantity of ore in a part of a lode (supposing the rectangular planes of surfaces representing the boundaries of the lode are parallel). (Height x width x depth) in cubic feet x 1,000 oz. x s.g. of ore, = weight in ounces of ore. Example : Find the weight of quartz in part of a lode 6 inches wide, 6 feet long x 6 feet deep. .. r . 6 in. x 72 in. X 72 in. Weight = " 1,728 X I ' X 2 ' 5 ' = 18 cubic feet x 1,000 X 2*5, = 45,000 oz. = 2,812 Ibs. approximately, = a little less than ij ton (2,240 Ibs. = i ton). N.B 1,728 cubic inches make one cubic foot, and a cubic foot of water = 1,000 oz. The reason that 1,000 is a factor in these calculations is that 1,000 ounces is the weight of i cubic foot of water, water being taken as the standard unit of specific gravity. N.B. In the case of quartz the number of tons in a lode may be known approximately by dividing the cubic feet of the lode by 15 (sometimes by less), as 15 cubic feet of average quartz weighs about i ton, though theoretically it might be 14, as in above example. To find the amount of ore and its value on a property, \et A c D B represent the horizontal surface of the property and A B the direction of the outcrop of the lode along the edge of it WEIGHT OF ORE IN A LODE. c A E = angle the lode B A E F makes with the horizon. The angle A E c = 90 c A E. E represents the point of the lode directly under c, i.e., the point where the perpendicular line to A c cuts the lode in depth. The cubical contents in feet of the lode = A B x A E x thickness of lode. \ Now A E = - 7 5 r^, and A B and angle sin (90 E A c)* E A c and the thickness of the lode are also known. > As in the previous Example, the weight in tons can be ob- tained, supposing the average specific gravity of the ore is known. FIG. 70. To find the value of the property, weight in tons x average yield in ounces per ton of ore, X value of the metal per ounce, = whole value. * Thus, if E A c is 60, A E . AC Q sin 30. i$t 7 HE PROSPECTOR'S HANDBOOK. The above calculation assumes that the surface is hori- zontal. Should, for instance, the outcrop be traced on the hill side, then it would be necessary to find also the area of the wedge-like body of ore, bounded by two parallel planes, one plane perpendicular to the base, the basal one, and also that of the slope. The area of such a wedge would be half that of one such as represented in Fig. 70. Horse-power of Water and Water Supply. The commercial value of a mine frequently depends on the power available, whether fuel in the shape of wood or coal, or water. The latter is the cheapest form of power, whether employed direct or converted into electrical force for conveyance to a considerable distance, in many cases amounting to several miles. The power of water depends on the amount in cubic feet per minute and the fall, or difference in level, between the proposed intake and outlet. The former must be measured and the latter ascertained by levelling or by the aneroid. Too much care cannot be taken in ascertaining these data. The quantity of water flowing in a stream naturally varies according to the season of the year, and it often happens that while a mill can be operated for, say, six months in a year by means of water power, during the remainder of the year steam must be supplied in reserve. Hence a double system is required, which necessitates fine calculations from a financial point of view. The prospector, however, will essentially want to know, first of all, the quantity of water available whether it is sufficient only for concentration purposes, or also for power. In the former, he desires to find out only the quantity available to supply his mill ; in the latter, he must know HORSE- POWER OF WATER, 153 both the quantity and the available fall, in order to be able to calculate the horse-power. Generally speaking, the amount of water required for steam and concentration purposes will be about 1000 gallons per ton per hour. If the stream is small, then the quantity can be obtained by the time required to fill a tub or reservoir of a known volume. With ordinary streams an approximate method is to choose a portion of it where the section is fairly regular, and to mark off a convenient distance, say, 20 yards along the bank. Then throw corked bottles or wooden floats into the stream/and note how long they take to travel the distance set out. This should be done several times by two different observers, and the mean of the observations taken. This wiF give the surface speed at the centre. Near the bottom and sides the water travels less quickly/ depending on the nature of the channel. If it is a wooden trough with smooth sides and bottom, take off 15 per cent. ; if a brick channel, 17 per cent.; if earth, 29 per cent; and if a rough mountain stream, 36 per cent. Having ascertained the average section of the stream, its area and mean speed, treat the figures as in the following example : vSuppose the area of the section of the stream to be 1 8 square feet, and the average speed in the centre 100 feet per minute, the sides and bottom being earth. First correct the speed, reducing it 29 per cent, and 71 feet per minute is left. Multiply this by 18 feet area, and the answer is 1278 crabic feet per minute. There are other methods of obtaining more accurate results by means of gauge boards, as it will be seen that owing to the great variation in the size and character of the various channels, the above method is only approximative. Having now obtained the quantity in cubic feet per 154 THE PROSPECTOR'S HANDBOOK. minute, and also the fall or difference in level, the actual brake horse -power, for turbines or wheels giving 75 per cent, efficiency, is found as follows : Fall X cub. ft. per min. TT ^ = n.r. 706 H.P. X 706 r n . , , . - r = fall required cub. ft. per mm. ' = cub. ft. per min. required, fall The average rainfall and the area of the gathering ground must also be taken into consideration in estimating the water supply. The effective horse-power of different water motors is shown in the following table : Theoretical H.P. . ' . . . . TOO Undershot waterwheels . , . 0*35 Poncelet's undershot wheels . . . 0*60 Breast wheels . . . . *" ./ 0*55 High breast wheels . . : . : . : . 0-60 Overshot wheel f .V . . . . 0*68 Turbine . . . ; . . ^ . . - 075 Pelton wheel . . . . -. ^ . . 0-85 GLOSSARY OF TERMS USED IN CONNECTION WITH PROSPECTING, MINING, MINERALOGY, ASSAYING, ETC. ABBREVIATIONS (Ctyern.) = Chemistry. (Mec.) = Mechanics. (Met.) = Metallurgy. (Eng.) = Engineering. (Min.) = Mining (Geo.) = Geology. /As.) = Assaying. (Phy.) = Physics. (Sur.) = Surveying. A. Acicular (Chem.) Needle-shaped. Acid (Chem.) A compound containing one or more atoms of hydrogen , which become displaced by a metal when the latter is presented in the form of a hydrate, Adamantine (Min.) Of diamond lustre. Aait (Min.) A horizontal entrance to a mine driven from the side of a hill. Agate (Geo.) Name given to certain siliceous minerals. Alkalies (Chem.) Potash, soda (and also ammonia and lithia). Alkalies turn vegetable blue, green ; and vegetable yellow, reddish brown. Blues reddened by an acid are restored by an alkali. Alkalies neutralize acids and with them form salts. They precipitate hydrates from their salts. Alloy (As.) A mixture of metals by fusion. Alluvial deposit (Geo.) A deposit formed of matter washed down or otherwise transported by a natural agency from higher ground. Aluminous (Min.) Containing alumina. Amalgam (Min.) A mixture of mercury with another metal, usually gold or silver. Amalgamation (Min.) The process of uniting mercury with gold or silver in an ore. Amalgamator (Met.) One who amalgamates gold and silver ores. Amorphous (Chem.) Without any crystal ization or definable form. Amurang (Ceylon) Gold ore. Amygdaloidal (Geo.) Almond-shaped. M 156 THE PROSPECTORS HANDBOOK. Analysis (Chem. ) An examination of the substance to find out the nature of the component parts and their quantities. The former is called qualitative and the latter quantitative analysis. Anneal (Met.) To toughen certain metals, glass, &c., by heating and then allowing to cool slowly. Anhydrous (Chem.) Without water in its composition. Anticlinal (Geo.) (See Chap. II.) Antimony crude (Met.) The mineral antimonite sweated out from its gangue. Antimony star (Met.) The metal antimony when crystallized, showing fernlike markings on the surface. Apex (Min.) The edge or outcrop of a vein. Apron (Eng.) A covering of timber, stone, or metal, to protect a surface against the action of water flowing over it. Aquafortis (Chem.) Name formerly applied to nitric acid. Aqua Regia (Chem.) A mixture of nitric and muriatic acid. One volume of strong nitric to three or four of hydrochloric acid is a good mixture. Aqueduct (Eng.) An artificial elevated way for carrying water. Arborescent (Met.) Of a tree-like form. Archean (Geo.) Crystalline schists supposed to be of metamorphic origin. Arenaceous (Geo.) Sandy. Areng (Borneo) Auriferous pay dirt. Argentiferous (Min.) Silver-bearing. Argillaceous (Min.) Clayey. Arrastra (Chem.) An appliance used for ore-reducing. The ore placed on a hard platform is crushed by means of mules dragging round large stones. Arroba (Spanish) 25 Ibs. Arsenide (Met.) Compound of a metal with arsenic. Asbestos The usual mineral of this name is fibrous and of a dull greenish colour, with pearly lustre. Assay (Chem.) Process for determining the amount of pure metal in an ore or alloy, usually by smelting or blowpipe examination. Assayer (Chem.) One who performs assays. Attle (Addle) (Min.) The waste of a mine. Attrition (Geo.) The act of wearing away by friction. Auriferous (Min.) Gold-bearing. Axle (Axle tree) (Mec.) The central bar on which the axle box revolves. Axle box (Mec.) The thimble or shell that turns upon the axle. Axe stone (Chem.) A species of jade. It is a silicate of magnesia and alumina. Azimuth (Sur.) The azimuth of a body is that arc of the horizon that is included between the meridian circle at the given place, and another great circle passing through the body. Azoic (Geo.) The age of rocks that were formed before animal life existed. GLOSSARY OF MINING TERMS. 157 B. Back of a lode (Min.) That part between the roof of the level and the surface. Backing (Eng.) The rough masonry of a wall faced with finer work ; earth deposited behind a retaining wall^ &c. Backlash (Min.) Backward suction of air currents, produced after an explosion o>$ fire-damp. Backs (Min.) The overlying portion of a lode that has not been worked. Back shift (Min.) Afternoon shift of miners. Back stay (Min.) A wrought-iron forked bar attached to the back of trucks when ascending an inclined plane, so as to throw them off the track in cas'a the hauling rope, or coupling^ gives way. Baffends (Min.) Long wooden wedges for adjusting tubbing plates or cribs in sinKing pits during the operation of fixing the tubbing. Bahar (Malay) Weight of 4 cwt. Balance box (Min.) A large box placed on one end of a balance bob> and filled wi'.h old iron, rock, &c., to counterbalance the weight of pump rods. Balanca brow (Min.) A self-inclined plane in steep seams on which a platform on wheels travels and carries the tubs of coal. Balance pit The pit in which the balance moves. Balk (Min.) A large beam of timber, (i) Timber for supporting the roof of a mine, or for carrying any heavy load. (2) A more or less thinning out of a seam of coal. Ballast (Eng.) Broken stone, gravel, sand, &c., used for keeping railroad sleepers steady ; also used in ships. Bank (Min.) The top of a pit, the surface around the mouth of a shaft. Bank claim (Min.) A mining claim on the bank of a stream. Barket (Min.) A gold-bearing conglomerate in which are white quartz pebbles (S. Africa). Bar (Min.) A course of rock of a different nature to the vein stone, which runs across a lode. A hard ridge of rock crossing a stream is called a bar in Australia, and on the upper side of which gold is likely to be deposited. Bar diggings (Min.) Gold-washing claims located on the bars (shallows) of a stream and worked when water is low, or otherwise with the aid of coffer-dams or wing-dams. Barrows (Min.) Heaps of waste stuff raised from the mine, also boxes with two handles at one end and a wheel at the other. Basalt (Geo.) (See Index.) Base metal (Met.) One that is not classed with the precious metals, gold, silver, platinum, &c., that are not easily oxidized. Basin (Geo.) A natural surface hollow. Basset (Min.) Outcrop of a lode or stratum. 158 THE PROSPECTOR'S HANDBOOK. Batea (Min.) A small, slightly conical dish, generally about 20 inches in diameter and 2j inches deep, in which gold-bearing soil is washed. Batt (Min.) Name given to a highly bituminous shale found in the coal measures. Button (Min.) A piece of thick board of not less than 12 inches in width. Batter (Eng.) The slope backwards of a face of masonry. Battery (Min.) A stamping mill or set of stamps for crushing purposes. Beach combing (Min.) Working the sands on a beach fur g Id, tin, or platinum. Bearers (Min.) Pieces of timber 3 to 4 feet longer than the breadth of a shaft, which are fixed at certain intervals apart and used as foundations for sets of timber. Bearing (Sur.) The course of a compass. Baaring (Mec.) The points of support of a beam axle or shaft. Beataway (Min.) A process of working hard ground by means of wedges and sledge hammers. Bed (Min.) Same as stratum or layer. Bed claim (Min.) A claim which includes the bed of a river or creek. Bed-plate (Eng.) A large plate of iron laid as a foundation for something to rest on. Bede (Min.) A kind of pickaxe. Bed rock (Min.) The rock on or in which alluvial deposits collect. Bed rock (Min.) The rock underlying an alluvial deposit, and on which at a gold diggings the most payable " dirt " usually rests. Belland A kind of lead poisoning lead miners are subject to. Belly (Min.) A swelling mass of ore in a lode. Ben, Benhayl (Min.) The productive portion of a tin stream. Bench (Australia) A terrace on the s.de of a river. Auriferous benches are termed reef wash. Bench (Min.) A terrace on the side of a river having at one time formed its bank. Bench mark (Sur.) A mark, cut in a tree or rock by surveyors for future reference. Bessemer steel (Met.) Formed by forcing air into a mass of melted cast iron, by which means the excess oi carbon present is separated from it until only enough remains to constitute cast steel. Beting (Malay) Quartz matrix carrying gold. Beton (Eng.) Concrete of hydraulic cement with broken stone, bricks, gravel, &c. Bevel The slope formed by trimming away an edge. Bevel gear (Eng.) Cogwheels, with teeth so formed that they can work into each other at an angle. Bin A box with cover, used for tools, stones, ore^ &c. Bind (Min.) Indurated argillaceotis shales or clay, very commonly forming the roof of a coal seam and frequently containing clay ironstone. Blng ore (Min.) The largest and best kind of lead ore. GLOSSARY OF MINING TERMS. 159 Bit (Min.) Steeled point of a borer^ or drill. Black band (Min.) Carbonaceous ironstone in beds, mingled with coaly matter, sufficient for its own calcination. Black batt, or Black stone (Min.) Black carbonaceous shale. Black-jack (Min.) Properly speaking dark varieties of zinc blende, but many miners apply it to any black mineral. Black ore (Min.) Partly decomposed pyrites containing copper. Black sand (Min.) Black minerals (magnetite, titanifeious iron, chromic iron, wolfram pleonaste, tourmaline^ cassiterite, &c.) accompanying gold in alluvial. Black tin (Min.) Dressed cassiterite, oxide of tin, ready for smelting. Blanch (Min.) A piece of ore found isolated in the hard rock. Blanket tables (Min.) Inclined planes covered with blankets, to catch the heavier minerals passing over them. Blast (Min.) To bring down minerals, rock, &c., by an explosion. (Met.) Air forced into a furnace. Blast pipe (Met.) A pipe for supplying air to furnaces. Blende (Geo.) Sulphide of zinc. Blind coal (Min.) Coal altered by the heat of a trap dyke. Blind creek (Geo.) A creek in which water only flows in very wet weather. Blind lode (Min.) One that does not show surface croppings. Blind shaft (Min.) A shaft not coming to the surface. Block coal (Min.) Coal in large lumps. Block claim (Australia) A square claim whose boundaries are marked out by posts. Block reefs (Australia) Those with longitudinal contractions. Block reefs (Min.) Reefs showing frequent contractions longitudinally. Blocking out (Australia) Washing gold-bearing matter in square blocks. Blcvsom rock (Min.) Coloured vein stone detached from an outcrop. Blow (Min.) A large increase in the size of a lode. Blow'jr (Min.) A sudden emission or outburst of fire-damp in a mine. Also a centrifugal ventilating fan. Blue elvan (Min.) Green-stone. Blue John (Min.) Fluorspar. Blue stone (Min.) (i) Sulphate of copper. (2) Lapislazuli. (3) Basalt. Bluff A high bank or hill with precipitous front. Bonanza (Min.) A large, rich body of ore. Band (Eng.) The arrangement of bricks in brickwork. Bongkal (Straits Settlements) A gold weight = 832*84 grains, 20 bongkals i catty. Booming (Min.) Ground sluicing on a large scale by emptying the contents of a reservoir at once on material collected below, thus removing boulders. Bornasca (Min.) An unproductive mine. Botrjoidal (Met.) With surface of rounded prominences. 160 THE PROSPECTOR'S HANDBOOK. Bottom (Min.) Bed rock. Bottom lift (Min.) The deepest column of a pump. Boulders (Geo.) Loose, rounded masses of stone detached from the parent rock. Box (Min.) A 12' x 14' section of a sluice. Boxing (Min.) A method of securing shafts solely by slabs and wooden pegs. Brace (Eng.) An inclined beam, bar, or strut, for sustaining compression. (Min.) A platform at the top of a shaft on which miners stand to work the tackle. Brace-heads (Min.) Wooden handles or bars for raising and rotating the rods when boring a deep hole. Branch (Min.) A small string of ore in connection with the main lode. Brasque (Met.) A mixture of clay and coke or charcoal, used for furnace bottoms. Brass (Min.) Iron pyrites. Brasses (Eng.) Fitting of brass mplummer blocks, &c., for diminishing the friction of revolving journals which rest upon them. Brattice (Min.) A partition in a drive or shaft for ventilation purposes Breakstaff (Min.) The lever for blowing a blacksmith's bellows, or for working bore rods up and down . Breast (Met.) The front part of a cupola furnace. (Min.) (i) The standing end of rock, lode, &c., immediately before one. (2) Timber placed across a drive behind the main set of timber, used in soft ground. Breastwall (Eng.) One built to prevent the falling of a vertical face cut into the natural soil. Breccia (Geo.) A rock composed of angular fragments cemented together. Breese (Min.) Fine slack. Bridle chains (Min.) Short chains, by means of which a cnge is attached to a winding rope. Brow (Min.) An underground roadway leading to a working place, driven either to the rise or the dip. Brownspar (Min.) A kind of dolomite containing, in addition to the carbonates of lime and magnesia, some carbonate of iron. Brownstone (Australia) Decomposed iron pyrites. Buckstone (Min.) Rock not producing gold. Bucket (Min.) A vessel used for holding rock, water, &c., to be hauled to the surface. (Eng.) (i) Each division on a water-wheel far holding water. (2) The top valve or clack of a lifting set of pumps. Bucketsword (Min.) A wrought-iron rod to which the pump bucket is attached. Bucket tree (Min.) The pipe between the working barrel and the wind bore. Bucking hammer (Min.) An iron disk provided with a handle- GLOSSARY OF MINING TERMS. i6i Bullion (Met.) Uncoined gold and silver. Base bullion is pig lead containing silver and some gold, which are separated by lefuiing. Bunch (Min.) A small rich deposit of ore. Burette (Chem.) A graduated glass tube provided with a stop cock, by means of which a certain quantity of liquid is allowed to drop out. Button (As.) Name given to the globule of metal which remains in the cupel after fusion. Also applied to the globule of a metal left in the slag from the scorification process. Byon (Min.) Ruby-bearing earth in Burmah. ) c. CafO (Brazil) A white quartz. Cage (Min.) -Elevator for hoisting and lowering the miners, as well as ore, 'Sec., in the mine. Cage-seat (Min.) Scaffolding, sometimes fitted with strong springs, to take off the shock, and upon which the cage drops when reach- ing the pit bottom. Cage sheets (Min.) Short props or catches on which cages stand during caging or changing tubs. Cainozoic (Geo.) Tertiary. Cairngorm (Geo.) A variety of quartz, frequently transparent : used as an ornament. Cajon (Bolivia) = 50 quintals. (Peru) = 60 (Chili) = 64 One marco of gold per cajon of ore = 2 oz. 14 dwt. per ton. Cake (Met.) An agglomeration, as when ore sinters together in roasting, or coal cakes together in coking. A cake of gold is retorted gold before melting. Calcareous Containing lime. Calcine (Met.) To drive off volatile matter by exposing the substance to a gentle heat, &c. Caloite (Chem.) Carbonate of lime. California!! pump (Min.) A rude pump made of a w r ooden box through which an endless belt with floats circulates ; used for pumping water from shallow ground. Cam (Eng.) A curved arm or wiper attached to a revolving shaft for raising stamps. (Min.) 'Carbonate of lime and fluorspar, found upon the joints of lodes. Cambrian (Geo.) Name given to the oldest (except the Laurentian) of the stratified rocks. Found in Wales. Canga (Brazil) A kind of auriferous glacial rock. Canny (Min.) Lode containing beds of carbonate of lime and fluor- spar is called canny. 162 THE PROSPECTOR'S HANDBOOK. Canon A deep valley. Cants (Eng.) The pieces forming the ends of buckets of a water-wheel. Cap (Min.) A piece of wood placed on props or legs in a drive. Cap rock (Geo.) The formation above the ore. Capstan (Eng.) A vertical axle used for heavy hoisting, and worked by horizontal arms or bars. Captain (Min.) Cornish name for manager or boss of a mine. Carat (Met.) Weight, nearly equal to four grains, used for diamonds and precious stones. With goldsmiths and assayers the term carat is applied to the proportions of gold in an alloy ; 24 carats represent fine gold. Thus 1 8- carat gold signifies that 18 out of 24 parts are pure gold, the rest some other metal. Carbona (Min.) A rich bunch of ore in the country rock connected with the lode by a mere thread of mineral. Carbonaceous (Geo.) Containing carbon. Carbonate (Chem.) Compound formed by union of carbonic acid with a base. Carboniferous (Geo.) Containing coal. Carburet (Chem.) A compound of a metal with carbon. Carga (Spain) A mule's load = 380 Ibs. Case ah! o (Brazil) A kind of gravel, auriferous and diamondiferous. Cascajo (South America) A decomposed schist on which pay-dirt lies. Casing (Min.) Material between a reef and its walls ; also the lining or tubbing of a shaft ; or also the partition of planks dividing a shaft into compartments. Catch-pit A reservoir to save tailings from reduction works. Catear (Min.) (Spain) To search for minerals. Caulk To fill seams or joints with something to prevent leaking. Gaunter lode (Min.) (Cornwall) A lode running across a main lode, or obliquely across the regular veins or lodes of the district. Cellular (Geo.) Containing cavities. Cement (Min.) A gravel of which the particles are cemented together. Cerro (Spain) Rocky hill. Chert (Geo.) A mineral like flint, only of a coarser texture and more brittle. It contains lime as well as silica. Chloride (Chem.) Compound of chlorine with an element, as, say chloride of silver. Chlorides (Min.) A common term for ores containing chloride of silver. Chloridize (Met.) To convert into chloride, as, for example, the roasting of silver ore with salt preparatory to amalgamation. Chlorination (Met.) The process of dissolving gold ores, after crushing and roasting, by the use of chlorine gas. Choke-damp (Min.) Carbonic acid gas left after an explosion of fire- damp. Chromate (Chem.) Chromic acid with a base. Churn-drill (Min.) A long iron bar with a cutting end of steel, used in quarrying, and worked by raising and letting it fall. When worked by blows of a hammer or sledge it is called a jumper. GLOSSARY OF MINING TERMS. 163 Chute (shoot) (Min.) (i) A wooden or metal pipe or hole in the ground for passing down minerals to a lower level. (2) The mineralized portion of a vein. Clack (Eng.) A common pump valve. Clack-door (Erg.) A cap near the valve that can be easily taken off, to allow an examination of the clack. Clack-seat (Eng. } The receptacle for the valve to rest on. Claim (Min.) Apportion of ground pegged out and held by virtue of a miners right. Clasp (Eng.) A snugly fitting ferru'e for connecting pump-rods to- gether. Cast and step when the rods clutch in cross -teps. Clasp and tongue when the tongue of one rod lies in a corresponding recess ot the other. Clavo (Mexico) A rich "pay" chimney, deep, but with horizontal limits. Clay course (Min.) A clay seam or gouge found at the sides of some vjins. Clay-slate (Geo.) Name given to some of the older stratified rocks, which are cleavable across the planes of stratification. Cleaning up The process of collecting the gold accumulated on the amalgamating plates of a stamp battery, or in the sluice boxes of hydraulic mining. Cleavage (Min.) The property of separating into layers. Clinometer (Sur.) (See Chap. II.) An instrument for measuring horizontal and vertical angles, and also the dipfof lodes. Coarse lode (Min,) Not a rich lode, the ore being only sparsely dis- seminated through it. Collar (Min.) A flat ring as on a line of shafting. Also the first wood frame of a shaft is called its collar. Color (Min.) (to show) An Australian expression when rock or gravel shows traces of gold. Colorados (South America) Red ores (stained by oxide of iron), similar to " gossan." Compact Of a firm texture. Concentric (Eng.) Having the same centre. Conchoidal (Geo.) Name given to a certain kind of fracture resembling a bivalve shell. Conformable (Geo.) (See Chap. II.) Conglomerate (Geo. ) Rounded stones cemented together to form a rock. Contact lode (Geo.) One between two distinct kinds of rock. Contour race (Min.) A watercourse following the contour of the land. Cord (of timber) A pile of wood 8 feet long, 4 feet high, and 4 feet broad ; contains 128 cubic feet. Costeaning (Min.) Trenching on the surface outcrop of a lode. Costean pits (Min.) Trenches cut at right angles to the strike of the lode. Country reck (Min.) The rock on either side of the lode in which the mineral veins or deposits are enclosed, or held. 164 THE PROSPECTOR'S HANDBOOK. Course (Miu.) The direction of a lode. Crab (Eng.) A variety of windlass or capstan being a short shaft or axle^ either horizontal or vertical, which serves as a rope drum for raising weights, it may be worked by a winch or handspikes. Crab holes (Min.) Holes often met with in the bed rock of alluvial. Also depression on the surface, owing to unequal decomposition of the underlying rock. Cradle (Min.) Australia A wooden apparatus or box mounted with a sieve for washing alluvial gold dirt. Crater (Min.) The cup-like cavity at the summit of a volcano. Creadero (South America) Indication of gold. Creaze (Min.) The middle of a buddle. Creek A small stream. Cretaceous (Geo.) Chalky. Crevicing 1 (Min.) Collecting gold in the crevices of rock. Crib (Min.) A cast-iron or wooden ring upon which the cast-iron or brick lining of a shaft is built. Crop (Min.) Ore of the first quality after it is dressed for smelting. Croppings (Min.) Parts of the vein above the surface. Cross-courses (Min.) Veins which usually cross the main lode at right angles. Cross-cut (Min.) A tunnel or level driven across the lode, or to meet the regular veins or lodes of the district. Cross spar (Min.) A vein of quartz which crosses a reef. Crucibles (Chem.) Fireproof vessels used in the roasting and melting of ores, &c. Crushing (Min.) The reduction of the crude ore by mechanical appliances to a size suitable for concentration, which process usually follows. In the case of gold, by amalgamation, &c., in that of lead, copper, zinc, &c., by concentration machinery. Crystallized (Chem.) Having well-defined crystals. Cubical Of the shape of a cube. Cupel (As.) A cup made of bone ash, for the absorption of litharge, as in the assay separation of silver from lead. Cut (Min.) To strike or reach a lode by means of an adit or cross-cut, usually as near as possible at right angles to the lode. Cyanide extraction (Met.) The process of dissolving out gold from crushed ore, by means of a dilute solution of cyanide of potassium. Largely employed all over the world for leaching or dissolving out gold from the sluices of stamp batteries. D. Dam (Eng.) An embankment for holding up water, or, as in South Africa, tailings. Damp (Min.) A term applied to dangerous gas escaping from the mineral formation in a mine. In metalliferous mines, usually GLOSSARY OF MINING TERMS. 165 " choke damp," "black damp," or "ground damp." In collieries, "firedamp." The former consist principally of carbon dioxide, the latter of light carburetted hydrogen. Deads (Min.) Ore that will not pay for working. Waste or rubbish in a mine. Debris (Min.) Disintegrated rock deposit, or the waste from a mine. Decant (Chem.) To pour off liquid (from the sediment) out of one vessel to another. Decrepitate (Ghent.) To crackle and fly to pieces when heated. Delia (Geo.) The alluvial land at the mouth of a river: usually bounded by two branches of the river, so as to be of a more or less triangular form. Denudation (Geo.) Rock laid bare by water or other agency. Deoxidation (Chem.) The removal of oxygen. Deposit (Geo.) Matter laid or thrown down ; for instance, mud or sand which, after suspension in water, has settled down. Desiccation (Chem.) The act of drying. Development (Min.) Work done in opening up a mine. Diagonal (Sur.) From one corner to another opposite. Dialling (Sur.) Surveying a mine by means of a dial. Die (Min.) The bottom iron block in a stamp battery, or grinding pan on which the shoe acts. Diggings (Min.) Places where gold or other minerals are dug out from shallow alluvials. Diluvium (Geo.) Drift deposit. Diorite (Geo.) Crystalline, whitish, speckled black, or greenish black. Chiefly consisting of felspar and hornblende, with oiten accessory minerals. Dip (Sur.) The angle which the lode or bed makes with the horizon \z called the dip. (See Chap. II.) Dirt (Mm.) That portion of alluvial workings in which most gold is found. disintegration (Geo.) Separated by mechanical means ; not by decomposition. Disseminated (Geo.) Scattered throughout a rock in the form of small fragments. Distillation (Chem.) The driving off vapours from a substance, and allowing them to condense on another surface or vessel. Ditch (Min.) An artificial watercourse, flume, or canal, for conveying water for mining purposes. Divining or Dowsing rod (Min.) A forked hazel twig, which, when held loosely in the hands, is supposed to dip downwards when passing over water or metallic minerals. Dolerite (Geo.) A kind of basaltic rock, nearly the same as diabase. Doles (Min.) Small piles of assorted or concentrated ore. Dolly (Australia.) An apparatus used in washing gold-bearing rocks, A rough kind of pestle and mortar. Dolly tub (Min.) A wooden tub used for concentrating ore, by hand. 1 66 THE PROSPECTOR'S HANDBOOK. Dolomite (Geo.) A mineral composed of the carbonates of lime and magnesia. Magnesian limestone. Dradge (Min.) Pulverized refuse. Draftage A. deduction made from the gross weight of ore when transported, to allow for loss. Draw a charge, To (Met.) To take a charge from a furnace. Drawlift (Eng.) A pump that receives its water by suction, and which will not force it above its head. Dressing (Min.) Preparing poor or mixed ores mechanically, for metallurgical operations. Dressing floors (Min.) The floors or places where ores are dressed. Drift (Min.) A loose alluvial deposit. A level in a mine. Drift (Min.) (i) Very loose alluvial deposits requiring close timbering to enable one to work them. (2) See Drive. Drifting (Min.) Winning pay-dirt from the ground by means of drives. Drill (Min.) An instrument used in boring holes. Drivings (Min.) Horizontal tunnels in a mine. Druse (Min.) A hollow ^space in veins lined with crystals. Drybone (Min.) A term used in America for calamine (carbonate of zinc). Ductile (Chem.) That can be drawn out into wire or threads. Dump (Min.) The place where ore taken from a mine is deposited. Dunes (Geo.) Small hills formed by sand blown together by the wind. Dyke (Geo.) Intruded igneous rock which fill up fissures and rents in stratified rocks. E. Earthy coal (Min.) Name sometimes applied to lignite or brown coal. Efflorescence (Chem.) An incrus:ation of powder or threads, due to the loss of the water of crystallization. Elbow (Min.) A sharp bend in a lode. Electric blast (Min.) Instantaneous blasting of rock by means of electricity. Electrolysis (Chem.) Separating chemical compounds into their com- ponent parts by means of electricity. Elevator pump (Eng.) An endless band with buckets attached, running over drums or pulleys, either for draining shallow ground, or for elevating ore in a concentrating mill from one floor to another. Elvans (Min.) Certain granitic and porphyritic rocks that traverse the granite and slate rocks of Cornwall. Emery ( M in. ) - Compact form of corundum. Is hard enough to scratch quartz and several gems. Erosion (Geo.) The wearing away of. Escarpment (Geo.) A nearly vertical natural face of rock or soil. Evaporat3 (Chem.) To cause to become a vapour. GLOSSARY OF MINING TERMS. 167 Exemptel claim (Australia) A mine allowed to remain unworked some time. Eye (Min.) Of a shaft, the beginning of a pit. F. Face (Min.) The extreme end of tunnel or other mining excavation. False tedding (Geo.) Irregular lamination, wherein the laminae, though for short distances parallel to each other, are oblique to the general stratification of the mass at varying angles and directions. F.lse bottom (Min.) In alluvial mining the term is applied to a stratum on wb'ich pay dirt lies, but underneath which are other bottoms. ''/ Fan (Min.) A machine for forcing air into or sucking from a mine, for ventibuicn. Fanegado (Min.) (Spain) 90^ F. = 100 acres. Fast (Min.) Term applied in Cornwall to solid rock immediately beneath the surface drift. Fathom (Min.) 6 feet. Fault (Min.) Dislocation along a fissure. Feather ore (Min.) A sulphide of lead and antimony. Feeder (Min.) A small vein running into a main lode. Feed pump (Eng.) A small pump for forcing water into a steam boiler. Fencing (Min.) Fencing in a claim is to make a drive round the boundaries of an alluvial claini^ to prevent wash-dirt from being worked out by adjoining r/tf/'/w-holders. Fend-off (Eng.) A sort of bell crank for turning a pump-rod past the angle of a'crooked shaft. Ferruginous (Chem.) Iron-containing. Filter (Chem.) To remove the particles of matter in a liquid by pouring it on to some substance, such as filter paper, so that the liquid runs through and leaves a solid residue behind. Fire bars (Eng.) The iron bars of a grate on which the fuel rests. Fire-damp (Min.) Carburetted hydrogen, an explosive gas. Firsts (Min.) The best ore picked from a mine. Fish (Eng.) To join two beams, rails, &c., together, by long pieces at their sides. Fissure (Geo.) An extensive crack, or rent in the rocks. Flags (Geo.) Broad flat stones for paving. Flange (Eng.) A projecting ledge or rim. Flat rod (Eng.) A horizontal rod for conveying power to a distance in connection with pumps. Fiats (Min.) In mining language, decomposed parts of limestone strata which are mineralized. These flats sometimes extend for a long distance horizontally, though they are not very thick. Flexible (Eng.) Capable of being bent without elasticity . i68 THE PROSPECTOR'S HANDBOOK. Flint (Geo.) A massive impure variety of silica. Float (Min.) Broken and transported pieces of vein matter. If sharp and angular, they have not come far ; but if rounded and worn, they may have travelled some distance. Also called shode, or shode stones. Float gold (Met.) Very fine gold dust which floats on running water. Floating reef (Min.) Lumps of gold-bearing rock found in alluvial beds. Float-stone (Min.) A cellular quartz rock. The honeycomb quartz detached from a )ode is often called float-stone by miners. Floor (Min.) A lode bent in a flat bed. A seam or joint in a rock. A false bottom. In quarrying, the bottom of a quarry. Floured mercury (ivlin.) Mercury which is useless for amalgamation purposes, on account of its having a film on it caused by sulphur, arsenic, or some other substance. Flour gold (Min.) The finest gold dust. Flouring (Min.) The separation of quicksilver in a stamp battery into-' fine globules, which refuse to reunite. This is apparently due to the formation of a thin coating of a sulphide, and is sometimes called sickening. Flukan (Min.) A vein filled with a soft greasy clay crossing or running in or under a lode. Flume (Min.) Apparatus (boxing or piping) used for conveying water from higher ground to alluvial gold diggings. Flux (Met.) A substance used to promote the fusion of metals in the reduction of ore. Foliated (Geo.) Arranged in leaf-like laminae (such as mica-schist). Foot-hole (Min.) Holes cut in the sides of shafts or winzes to enable the miners to pass through them. Foot-piece (Min.) (i) A wedge of wood or part of a slab placed on the foot wall, against which a stull piece is jammed. (2) A piece of wood placed on the floor of a drive to support a leg or prop of timber. Footwall (Min.) The under wall of a lode. Footway (Min.) Ladders by which miners descend or ascend the shafts of a mine. Fore-bay or Penstock (Eng.) The small reservoir in which the water from a ditch or flume is collected and roughly filtered, before it passes on to the water-wheel, turbine, or concentration machinery, Fork (Eng.) A deep receptacle in the rock to enable a pump to extract the bottom water. A pump is said to be " going in fork " when the water is so low that air is sucked through the ivind-bore. Formation (Geo.) A series of strata comprising those that belong to a single geological age. Fossicking (Min.) Overhauling old workings and refuse heaps for gold or other minerals, sometimes called " crevicing." GLOSSARY OF MINING TERMS. 169 Fossil (Geo.) Term applied to express the animal or vegetable remains found in rocks. Fossiliferous (Geo.) Containing fossils. Frame (Min.) A slightly inclined table composed of boards, used in the washing of tin to remove the waste. Frame set (Min.) A. frame or set of timber, consisting of two legs and a cap, used underground for the supporting of the sides and roof of a level. Free milling (Min.) Ores containing free gold or silver, which can be recovered by*amalgamation with mercury. Freeze (As.) (See Chap. IX., Cupelling). Freshet (Min.) A flood or overflowing of a river caused by heavy rains or the melting of snow. Friable (Min.) Easily powdered. Fuller's Earth (Min.) An unctuous clay (usually of a greenish -grey tint) ; compact yet friable. Used by fullers to absorb moisture. Fuse (Min.) In blasting, the fire is conveyed to the blasting agency by means of a prepared tape or cord called the fuse ; in metallurgy, to m-lt. Fusible (Min.) That can be fused or melted. Fusion (Met.) Making liquid by heating. Gabro (Min.) Name given to a particular kind of rock in which diallage predominates. Gad (Min.) A steel wedge used in underground mining. Gallery (Min.) A horizontal excavation in a mine. Gamell.3 (Min.) (Brazil) Wooden bowl for " panning out" gold. Gangue (Min.) The veinstone, vein stuff, or matrix of a vein or lode, in which the mineral matter is embodied, and from which it can only be separated by mechanical or chemical treatment. Gash vein (Min.) A wedge-shaped vein, as distinguished from a true fissure vein or lode. Gem (Geo.) A precious stone. Geodes (Geo.) Large nodules or lumps of stone with a hollow in the centre. Geyser Eruptions of heated water. Gin (Min.) Called also whim. A drum on a vertical axis, worked by horse-power for raising ore from a shallow mine. Glacier (Geo.) A body of ice which descends from the high to the low ground. Glance (Met.) Literally, shining. Name applied to certain sulphides. Globule (Chem.) A small substance of a spherical shape. Gneiss (Geo.) Metamorphic or altered rock. Gob or Goaf (Min.) That part of a mine from which coal, &c., has been worked away, and the space more or less filled up. Gold (Min.) See Alluvial, Paint y Flour, Rust gold, &c. i;o 777^ PROSPECTOR'S HANDBOOK. Gossan (Min.) Quartz rock with iron oxide as stains or in small cavities. Found on the surface or near the top of a lode. Grade (Eng.) The amount of fall or inclination in ditches^ flumes, roads, &c. Also in mining, an ore which carries a great or comparatively small amount of valuable metal is called respectively a high or low grade ore. Granite (Geo.) Intrusive rock. An intrusive rock. Granulated (Chem.) In the form of grains. Granzas (Spain) Poor ores. Grass Boots (Min.) At the surface, or at the surface of the ground. Grating (Min.) A perforated iron sheet or wire-gauze placed in front of reducing machinery. Gravel (Geo.) -Water-worn stones about the size of marbles. Grede (Venezuela) A yellow iron-stained clay. Greenstone (Geo.) A granular trap rock. Contains hornblende and felspar in small crystals or grains. Greisen (Geo.) An altered granitic rock, grey in colour. Greywacke (Geo.) A compact grey sandstone frequently found in Paleozoic formations. Griddle (Min.) A coarse sieve used for sifting ores, clay, c. Grit (Geo.) A variety of sandstone of coarse texture. Grizzly (Min.) (America) Bars set in a flume to intercept the large stones. Groin (Eng.) An arch formed by two segmental arches or vaults inter- secting each other at right angles. Groundsill (Min.) A log laid on the floor of a drive on which the legs of a set^ rest. Ground sluicing (Min.) Washing alluvial, loosened by pick and shovel, in trenches cut out of the bed rock, using bars of rock as natural riffles. Used in shallow placers, hill claims, and stream diggings. Grout (Eng.) Thin mortar poured into the interstices between stones and bricks. Guano (Geo.) A brown, grey, or white, light powdery deposit, con- sisting mainly of the excrement of seafowl in rainless tracts, or of bats in caves. Gudgeons (Eng.) The metal journals of a horizontal shaft. Gaides (Min.) Continuous lengths of ropes or squared timber which run down the drawing compartment of a shaft for keeping the cage in position, while ascending and descending. Gulch (Min.) A ravine. G allies (Min.) (Cornwall) Worked-out cavities. Gaily (Min.) Feeder of a creek. G assets (Eng.) Plain triangular pieces of plate iron riveted by their vertical and horizontal legs to the sides, tops, and bottoms of box- girders, tubular bridges, &c., inside for strengthening their angles. Gutter (Min.) (i) A small water-draining channel. (2) The lowest part of a lead that contains the most highly auriferous dirt. Guy (Eng.) A stay of iron, wood, rope, or chain. GLOSSARY OF MINING TERMS. 171 H. Hacienda (Spain) House where ore is melted, or a dwelling-house. Hade (Min.) Dip of a lode. Halter (Min.) (New Zealand) A miner working on his own account. Halvans (Min.) Waste of copper or other ores. Hanging wall (Min.) The upper wall of a lode. Harrow (Australia) An apparatus used for mixing gold-bearing clays, and is not unlike an agricultural harrow. Head (Eng.) Pressure of water in Ibs. per square inch. (Min.) Axiy subterraneous passage driven in solid coal. Also that part of a face nearest the roof. Head-board (Min.) A wedge of wood placed against the hanging wall ^ and against which one end of the stull piece is jammed. Header (Mm.) (i) A rock that heads off or delays progress. ^ (2) A blast hole at or above the head. (Eng.) A stone or brick laid lengthwise at right angles to the face of the masonry. Heading (Min.) (l) A small driftivay or passage excavated in advance of the main body of a tunnel, but forming part of it, for facilitating the work. (2) Coarse gravel or drift overlying the wash-dirt. Heading side (Min.) The under side of a lode. Headings (Min.) Coarse gravel above gold-bearing " wash-dirt." Head-race (Min.) An aqueduct for bringing a supply of water. Heave (Min.) When the lode stops at the en 1 of a level on account of a cross-course, it is said to be "hove." Heavy gold (Australia) Gold of the size of gunshots. Hechado,(Spain) The dip of a lode. Hemma (Sanskrit) Gold. High-reef (Min.) The bed rock or reef is frequently found to rise more abruptly on one side of a gutter than on the other, and this abrupt reef is termed a high- reef. Hitch (Min.) A fault or dislocation of less throw than the thickness of the seam in which it occurs. Hitches (Min.) Steps cut in the rock or lode for holding stay-beams^ beams, or timber, &c., for various purposes. Hole (Min.) To undercut a seam of coal, &c. Horn (Min.) A piece of bullock's horn about 8" in length, cut boat- shape, for concentrating by water on a small scale. Also a hard siliceous rock. Hornblende (Geo.) A very common mineral, so called from its horn- like cleavage and lustre. Usually dark green and blackish, but occasionally of light colours. Hornstone. (See Chert.) Horse (Min.) A term applied to masses of country rock found in a lode. Horse-flesh ore (Min,) Purple copper ore, N 172 THE PROSPECTOR'S HANDBOOK. Horse-power (Eng.) Work equal to raising 33,000 Ibs. one foot high per minute. HorsewMm (Min.) A vertical drum worked by a horse for hauling. Hose (Min.) A strong flexible pipe, made of leather, canvas, rubber, &c., and used for the conveyance of water under pressure to any particular point. Hurdy-Q-urdy (Eng.) A water-wheel which receives motion from the force of travelling water. Hungry (Min.) A term applied to hard, barren vein matter, such as white quartz. Hydraulic hose (America). The hose used to conduct a stream of water, the force of which washes down the face of the alluvial gold-bearing deposit. Hydraulic mining. Washing down gold-bearing earth by means of a powerful jet of water. Hydrous (Chem.) Containing water in its composition. i. Igneous (Geo.) Certain rocks which have been subjected to heat. (See Chap. II.) Inch, miner's (America). Varies in different localities in Western America. The usual one (which discharges 95 cubic feet per hour) is the amount of water that will flow through a horizontal opening, an inch square, under a head of six inches. Incline (Min.) A slanting shaft. Incrustation. A coating of matter. In-fork (Min.) A pump is said to bein-fork when it continues working after the water has fallen below the holes in the wind-bore, the pump sucking air. Ingot (Met.) A lump of cast metal. Iridescent. Showing rainbow colours. Iron-hat or cap (Min.) The oxidized ferruginous mineral on the out- crop of a lode. J. Jack (Eng.) An apparatus for lifting heavy weights. May be either a screw-jack, or an hydraulic jack. Jacotinga (Brazil). Iron ores associated with gold. Jeweller's shop (Australia). Rich patch of gold-bearing matter. Jigging (Min.) A process of sorting ores by means of an apparatus having a vertical motion in water, called a Jig or Jigger. Joints (Geo.) Natural divisions, cracks, or parting* in the strata. Journals (Eng.) The cylindrical supporting ends of a revolving horizontal shaft. Jump (Min.) (i) To take clandestine possession of another's claim. (2) An up-throw or doivn-throiv fault. GLOSSARY OF MINING TERMS. 173 Jumper (Min.) A drill used for Coring in stone by simply lifting and dropping. It frequently has an enlarged knob or weight in the middle, and may be sharpened at one or both ends. K. Kal (Min.) A coarse kind of iron. Kaolin (Geo.)^\ white clay produced from decomposed orthoclnse felspar. Keelwedge (Er.g.) A long iron wedge for driving over the top of a pick ///'//, Keeve (Min.) A large wooden tub used for the final concentration of tin oxi Je. Key (Eng.) (i) An iron bar of suitable size and taper for filling the keyways of shaft and pulley so as to keep both together. (2) A kind of spanner used in deep boring by hand. Keybolt See Cotter-bolt. Keystone The centre stone of an arch. Keyways (Eng.) Suitable corresponding grooves in shaft and ptilley for receiving the key. KibuIe(Min.) The bucket used for raising stones, &c., from shafts. Kick-up (Min.) An apparatus for emptying trucks. Killas (Min.) A name applied in Cornwall to a hard slate or shale through which lodes run. Kiln (Met.) A chamber built of stone or brick or sunk in the ground for burning minerals in. Kind (Min.) (i) Tender, soft, easy. (2) Likely looking stone. King post (King rod) The centre post, vertical rod or piece, in a truss ; similar posts or rods when not at the centre, are Queen posts or rods. Kit Any workman's really necessary travelling outfits, as tools, &c. Knee-piece (Eng.) A bent piece of piping. Knocker (Min.) A lever which strikes on a plate of iron at the mouth of a shaft, by means of which miners below can signal to those on the top. Knocker-line (Min.) The signal line extending down a shaft from the knocker. Knuckle-joint (Eng.) Two rods connected together by a pin in such a way, that one laps each side of the other, thus affording a free side motion. Ladder way (Ladder road) (Min.) The particular shaft or compartment of a shaft used for ladders. 174 THE PROSPECTOR'S HANDBOOK. Lagging (Min.) Thick flat boards fastened over the outside of regular frame timber of shafts and levels, in order to more safely secure the ground. Lagoon A shallow lake, pond, or marsh. Lamina (Geo.) A thin slice in the plural laminae. Rocks such as slates and schists are said to be laminated. Lander (Min.) The man who receives a load of ore at the moiith of a shaft. Lander's crook (Min.) A hook or tongs for upsetting the bucket of hoisted rock. Lap (i) To place one piece upon another with the edge of one reaching beyond that of the other. (2) One coil of rope upon a drum or piilley. Launder (Eng.) A flume or aqueduct. Lava (Geo.) A common term for all rock matter that has flowed from a volcano or fissure. Lavadoros (Spain) Gold washings. L)achlng (Met.) To dissolve out by some liquid. Lsad (pronounced leed) (Min.) (i) Ledge (America), Reef( Australia), Lode or vein (England). A more or less vertical deposit of ere, formed after the rock in which it occurs. (2) A bed of alluvial pay-dirt or auriferous gutter. (3) The distance to which earth is hauled or wheeled. Loader (Min.) A small vein supposed to lead to a larger one. (Eng.) A cog-wheel that gives motion to the next one or follower. Loadings (Australia) The unprofitable dirt above pay-dirt. Loat A small water ditch. Lodge (Min.) A lode. Log-piece (Min.) An upright log placed against the side of a drive to support the cap-piece. Lonticular (Geo.) Shaped like a double convex lens. Lense shaped. Lovel (Min.) An underground road driven in the rock or lode. L f: of pumps (Min.) The arrangement of pumps in a mine from one stage or level to another. Ligneous (Geo.) Of a woody nature. Lignite (Geo.) Half-formed coal, in which the woody structure has not been totally destroyed. Lining (Min.) The planks placed between the setts either in a shaft or level. Little Giant (Min.) The name given to the nozzle of the pipes used in hydraulic mining. Litharge (Chem.) (Protoxide of lead) Used as a flax by assayers. Llxiviation (Chem.) The separation of a soluble from an insoluble material in a solvent. GLOSSARY OF MINING TERMS. 175 Loadstone (Geo.) An iron ore consisting of protoxide and peroxide of iron ; is magnetic. Loam (Geo.) A mixture of fine sand and clay. Lob of gold (Australia) Rich gold deposit found in an area of small extent. Locate To establish a right to a mining claim. Lode (Min.) A longitudinal fissure or chasm filled with ore-bearing matter and/.between two walls. Lode plot (Mir/.) A horizontal lode. Long Tom (Mm.) An apparatus used in the washing of gold-bearing " dirt." Usually a wooden sluice about 24 ft. long and 2 ft. wide and a foot deep. Lute (Chem.) Pasty matter to close joints of chemical apparatus and f.o coat surfaces so as to protect them from the action of flame. M. Macizo (Spain) The part of a lode unworked. Malleable (Eng.) Capable of be'nj sliced and hammered out. Man engine (Min.) Machine by which men ascend and descend a mine. Manto (Spain) A single layer of a stratum. Marco (Spain) Weight = 8 ounces. Marl (Geo.) Clay containing carbonate of lime. Matrix (Min.) The mineral associated with ore in a lode. (See Chaps. I. and VII.) Matte (Met.) See Regulus. Meerschaum (Geo.) A white soft mineral, dry to the touch, and adhering to the tongue when licked by it. Is a silicate of magnesia. Specific gravity '8 to ro when dry. Occurs in veins or in kidney- shaped nodules in serpentine rocks. Mesa A tableland. Metales calidos (hot metals) (South America) Minerals capable of amalgamation, such as native silver, hornsilver, &c. Metales frios (cold metals) Minerals not suitable for the amalgamation process. Metallurgy Art of extracting metals from their ores, &c. Metamorphic Applied to rocks which through heat, pressure, and time have been altered in their constituents, converting oidinary and soft deposits into hard and crystalline rocks. Mill (Met.) The installation of machinery in which the crude ore is crushed, concentrated, and prepared for market. Miner's-inch (Min.) A method of measuring the quantity of water flowing through a given aperture at a fixed head, usually one inch square under a head of six inches. Mock ore (Min.) A false kind of mineral. Monton (Spain) A pile of ore. In Mexico a monton = 17 quintals. 176 THE PROSPECTOR'S HANDBOOK. Mortar (Min.) As a pestle and mortar. In a stamp battery the cast- iron vessel in which the stamp falls. Mother lode (Min.) The principal lode of a district. Mountain blue (Min.) Blue copper ore. Mountain cork (Min.) A variety of asbestos. Mountain green (Min.) Malachite. Mountain limestone (Geo.) Carboniferous limestone. Muestras (Spain) Samples of ores. Muffle (Chem.) A small oven-shaped fire-proof furnace. Mullock (Australia) Debris of the country rock filling a fissure. Mundic (Min.) Iron pyrites. Muschelchalk (German) A limestone formation containing fossil shells. N. Native metal (Geo.) A metal found in its natural state as gold usually and sometimes silver and copper. Nitrate (Chem.) Nitric acid chemically combined with a base. Nodule (Geo.) A rounded rock, or concretion, frequently found to enclose organic remains. Nozzle (Eng.) The front piece of a water or air pipe. Nugget (Min.) A lump of native metal. Usually applied to gold. o. Oitavo (Spain) About the eighth part of an ounce. Ojo (Spain) A bunch of ore. Olivine (Geo.) A glassy looking olive-green mineral occurring in many basic igneous rocks. Old man (Min.) Workings made by former owners of a mine, mostly ancient. Onca (Spanish) = 44272 grs. troy. Oolitic (Geo.) A structure peculiar to certain rocks, resembling the roe of a fish. Open-cast (Min.) Workings having no roof, as in a quarry. Open- cut (Min.) To commence working after sinking the shaft. Open-cutting (Min.) An excavation made on the surface for the purpose of getting a face wherein a tunnel can be driven. Ores (Min.) Minerals or mineral masses from which metals or metallic combinations can be extracted on a large scale, in an economic manner. Ore-shoot, or chute A large and usually rich body of ore in a vein. Organic Something animal or vegetable, that has life or has lived. Orthoclase (Geo.) A certain kind of felspar of various colours. Out-bye (Min.) In the direction of the/// bottom. Out-crop (Min.) The exposure of a mineral deposit at the surface. GLOSSARY OF MINING TERMS. 177 Out-set (Min.) The walling of shafts built up above the original level of the ground. Overburden (Min.) The covering of rock, earth, &c., overlying a mineral deposit which must be removed before effective work can be performed. Overhand stoping (Min.) The ordinary method of stoping upwards. Overlap fault (Geo.) A fault in which the shifted strata double back over themselves. Oxide (Chem.)y-A chemical combination of oxygen and a base. Oxidation (Ch3279slO)476B .General Library University of California Berkeley