GETTING GOLD.
GRIFFIN’S STANDARD PUBLICATIONS.
Fourth Edition, Revised. Fully Illustrated. 21s.
THE METALLURGY OF GOLD. By T. KIRKE ROSE, D.Sc. Lond., Assoc. R.S.M., Chemist and Assayer to the Royal Mint.
“Adapted for all who are interested in the Gold Mining Industry, being free from technicalities as far as possible, but is more particularly of value to those engaged in the industry.”—Cape Times.
“A comprehensive practical treatise on this important subject.”—The Times.
Medium 8vo. With numerous Plates, Maps, and Illustrations. 21s. net.
CYANIDING GOLD AND SILVER ORES: A Practical Treatise on the Cyanide Process. By H. FORBES JULIAN, and EDGAR SMART, A.M.I.C.E.
“A handsome volume of 400 pages which will be a valuable book of reference for all associated with the process.”—Mining Journal.
Large Crown 8vo. Third English Edition. Fully Illustrated, 7s. 6d.
THE CYANIDE PROCESS OF GOLD EXTRACTION. By Professor JAMES PARK, F.G.S., M.Inst.M.M.
“We can confidently recommend this book as a thoroughly practical work, and congratulate the author at its continued success.”—Chemical News.
In Crown 8vo. Illustrated. Fancy Cloth Boards. Price 4s. 6d.
GOLD SEEKING IN SOUTH AFRICA; A Handbook of Hints for intending Explorers, Prospectors, and Settlers. By THEO. KASSNER, Mine Manager.
“The Prospector ought to include this book in his library of reference, and the stay-at-home reader will be interested and informed by its contents.”—Mining World.
Third Edition, Revised. With Illustrations. Handsome cloth, 5s.
PROSPECTING FOR MINERALS. By S. HERBERT COX, Assoc. R.S.M., M.Inst.M.M., F.G.S., &c.
“This EXCELLENT HANDBOOK will prove a perfect vade-mecum to those engaged in the practical work of Mining and Metallurgy.”—Times of Africa.
Large 8vo. Cloth. Fully Illustrated. 12s. 6d. net.
METALLURGICAL ANALYSIS AND ASSAYING: A THREE YEARS’ COURSE FOR STUDENTS OF SCHOOLS OF MINES. By W. A. MACLEOD, B.A., B.Sc., A.O.S.M., and CHAS. WALKER, F.C.S.
“The publication of this volume tends to prove that the teaching of metallurgical analysis and assaying in Australia rests in competent hands.”—Nature.
In Large 4to. Library Style. Beautifully Illustrated with 20 Plates, many in Colours, and 94 Figures in the Text. £2, 2s. net.
PRECIOUS STONES: THEIR PROPERTIES, OCCURRENCES, AND USES. By Dr. MAX BAUER. Translated by L. J. SPENCER, M.A. (Cantab.), F.G.S.
“The plates are remarkable for their beauty, delicacy, and truthfulness. A glance at them alone is a lesson on precious stones.”—Athenæum.
London: CHARLES GRIFFIN & CO., Limited, Exeter St., Strand.
Frontispiece
GETTING GOLD:
A PRACTICAL TREATISE
FOR
PROSPECTORS, MINERS, AND STUDENTS.
BY
J. C. F. JOHNSON, F.G.S.,
MEMBER OF THE AUST. INST. OF MINING ENGINEERS;
AUTHOR OF “PRACTICAL MINING,” “THE GENESIOLOGY OF GOLD,” ETC.
THIRD EDITION.
WITH 50 ILLUSTRATIONS AND 8 PLATES.
LONDON:
CHARLES GRIFFIN AND COMPANY, Limited;
EXETER STREET, STRAND.
1904.
[All rights reserved.]
PREFACE TO THE FIRST EDITION
Some years ago the author published a small book entitled “Practical Mining,” designed specially for the use of those engaged in the always fascinating, though not as invariably profitable, pursuit of “Getting Gold.” Of this ten thousand copies were sold, nearly all in Australasia, and the work is now out of print. The London Mining Journal of September 9th, 1891, said of it: “We have seldom seen a book in which so much interesting matter combined with useful information is given in so small a space.”
The gold-mining industry has grown considerably since 1891, and it appeared to the writer that the present would be a propitious time to bring out a similar work, but with a considerably enlarged scope. What has been aimed at is to make “Getting Gold” a compendium, in specially concrete form, of useful information respecting the processes of winning from the soil and the after-treatment of gold and gold ores, including some original practical discoveries by the author. Practical information, original and selected, is given to mining company directors, mine managers, quartz mill operators, and prospectors. In “Rules of Thumb,” chapters XI. and XII., will be found a large number of useful hints on subjects directly and indirectly connected with gold-mining.
The author’s mining experience extends back thirty years and he therefore ventures to believe with some degree of confidence that the information, original or compiled, which the book contains, will be found both useful and profitable to those who are in any capacity interested in the gold-mining industry.
J. C. F. J.
London, November 1896.
PUBLISHERS’ NOTE TO THE THIRD EDITION
The reviewer in Nature remarked on the First Edition of this book, “It has often been said that the practical man does not write books, but THERE IS HERE A COMPLETE REFUTATION OF THE CALUMNY.” The sale of two large editions has justified the opinion of the reviewer, and shows that the book from the practical man is valued. The Third Edition has been revised throughout and several new figures in the text and eight full-page plates have been added. It is confidently hoped that this new Edition will meet with the same kindly reception as the earlier ones.
November 1904.
CONTENTS
CHAPTER I
Gold—Poetical and historical references—Its wide distribution—Remains of ancient works—Old appliances—Modern appliances anticipated—Labours of alchemists—Deposition similar to common minerals—How first obtained—The Pactolian annual miracle—Mode of working auriferous sand and lodes—Principal sources of gold supply—Transvaal production—Californian production—Real date of discovery in Australia—State encouragement for new discoveries—Obstacles in early Australian production—Australasian production to date—The world’s wealth—Nuggets—Modern methods—Hydraulicing cheapest—Definition of “lode”—Igneous and aqueous theories contrasted—Difference between reef and alluvial gold—Mining terms explained—Usual exploitation and treatment—Operations—Stamp battery—Its advantages as crusher—Usual milling operations.
pp. 1-12
CHAPTER II
GOLD PROSPECTING
(ALLUVIAL AND GENERAL)
Ignorance of prospectors—Chapter specially addressed to the inexperienced—Valuable finds mostly accidents—Best way to obtain elementary knowledge—An assaying experience—What a prospector should know—Usual geological conditions of most minerals—Unwise to follow theories blindly—Instances of unlikely occurrences of gold—Importance of examining outcrops—Curious matrices for gold—Alluvial and reef gold—Hints to prospectors—Prospecting for alluvial gold—Tin dish—Dry blowing—Size of prospecting shaft—Intricacy of deep leads—How to recognise true bottom—Gold bearing “gutters”—Difference in working shallow and wet ground.
pp. 13-21
CHAPTER III
LODE OR REEF PROSPECTING
Likeliest localities for reefs—Similarity of indications of minerals—Where first prospecting is done—A practical example—Ironstone “blows”—Their true origin—Igneous theory untenable—Usual trend of lodes in Australia—Exceptions to the rule—Instances of rich deposits apart from lodes—Sinuosity of lodes—How to trace lodes demonstrated—Examine all indications—How to recognise gold, silver, copper, tin—How to ascertain their value—Caution in sinking—Where to prospect in case of parallel lodes—Usual underlie in Australia—Size of prospecting shaft—Tip for mullock—How to distinguish gold from pyrites or mica—Estimating value from prospect—How to pan—An amalgamating assay method—Author’s device when antimony present—Battery, best test—Silver and tin indications—Lode tin, stream tin, difficulty of recognising tin—Lode tin always near granite—Minerals often mistaken for tin—How to discriminate—Tin in Westralia.
pp. 22-33
CHAPTER IV
THE GENESIOLOGY OF GOLD
(AURIFEROUS LODES)
Igneous theory formerly strongly upheld—Quotation from Rosales—His arguments combated—Hydro-thermal action—Its evidences in New Zealand—Professor Lobley’s theory—Author’s deposition theory confirmed—Later works—Conclusions of Le Conte—Metamorphic slates and earlier Silurian strata theory—Formation of mineral lodes—What was gold originally?—Metal or metallic salt—Silicate hypothesis preferred—Explanation of sulphides and silicates of gold—Bischof’s interesting experiment—Skey’s and other deposition experiments—How gold took its metallic form—The Comstock lode—Occurrence of gold in shutes explained—Why lode junctions are usually rich—Cox’s theory—Instances of lodes re-forming—Gold as natural sulphide—Newbery’s theory of gold in pyritous lodes—Probable occurrence in pyritous ores as sulphide.
pp. 34-47
CHAPTER V
THE GENESIOLOGY OF GOLD
(AURIFEROUS DRIFTS)
Derivation and occurrence—Old diggers’ “growing” theory—Deposition experiment illustrating nature—Denudation of quartz lodes theory—Examples of its probability—Nuggets require other explanation—Deposition, most rational theory—Usual alluvial theory combated—Daintree’s and Wilkinson’s deposition experiments—Spondulix and Lothair nuggets—Newbery’s deposition experiments—Nugget form explained—Author’s experiments in manufacture of golden quartz—Extract from author’s “Deposition of Gold”—Remarkable nugget—Reason of superiority of alluvial gold.
pp. 48-58
CHAPTER VI
GOLD EXTRACTION
Division of methods of treating ores—Scientific extraction indispensable—Superficial knowledge—German and Australian methods compared—Schools of Mines—Antiquity of gold working—Miner’s equipment—Tub, cradle, long tom—How operated—Hydraulic mining—Extensive Australian drifts—Extraction of reef gold—Amalgamation—Crushing appliances—Preference for stampers—The Lemichel syphon—The Griffin mill—The Huntingdon mill—Dodge crusher—Krupp Grusonwerk Ball Mill—Premature plant erecting—Danger of untried processes—Double faulted lode—Automatic ore feeders—Machinery site—Foundations for battery—Weight of stamps—Power and water required for battery—Selection of screen—Fall of tables—Ancient Egyptian gold washing table—Blanket tables—Successful treatment of refractory ore in Australia—Methods vary with ore—Importance of even crushing—Points re crushing—Best form of stamper box—Cleaning plates—Form of scraper—Retorting
pp. 59-86
CHAPTER VII
GOLD EXTRACTION
(SECONDARY PROCESSES AND LIXIVIATION)
Choosing the plant—-Various ores and their constituents—Amalgamation—Various concentrators—Percussion tables—Frue vanner—Pan concentration—Simultaneous grinding and amalgamating condemned—Watson and Denny pan—Good machines often condemned—Procedure in ore treatment—Duncan pan—Calcining—Rotatory amalgamator—Steaming concentrates—Dry amalgamation—Sulphuric acid and sickened mercury—Amalgamation without overflow—Experiments—Steam as an agent in gold extraction—Lixiviation by chlorine—Various processes—Mount Morgan—Cyanide process.
pp. 87-99
CHAPTER VIII
CALCINATION OR “ROASTING” OF ORES
Effect of roasting—Various methods—Reverberatory furnaces—Howell, White, Brückner, Thwaite-Denny, and Molesworth types of revolving cylinder furnaces—Shaft type—The Stetefeldt furnace—Chimneys—Depositing chambers.
pp. 100-108
CHAPTER IX
MOTOR POWER AND ITS TRANSMISSION
Water and steam power—Waterless power plant described—Oil engines—Electric transmission—Advantages of electric power—Its possibilities.
pp. 109-112
CHAPTER X
COMPANY FORMATION AND OPERATIONS
Mining becoming a scientific business—Initial mistakes in public companies—Self-styled mining experts—How articles of association are compiled—How directors and officials are chosen—The usual consequences—Remedies—State inspectors—Certificates for mine managers—Directors—Specialists in various branches advisable—Qualifications of mine managers—Economic advantages of co-operation—Joint central extraction works—Folly of adopting untried new processes without full knowledge—Pertinent quotation—Warning to directors—Robbing mills—How prevented—Conclusion.
pp. 113-126
CHAPTER XI
RULES OF THUMB
Living places—A bush bed—Northern Territory hammock—Purifying water—To obtain water from roots—An effective filter—Canvas water-bag—Medicine case—Producing fire—To copy correspondence—Simple telegraphic code—A serviceable soap—To cross a flooded stream—To make a hide bucket—To make a “slush lamp”.
pp. 127-139
CHAPTER XII
RULES OF THUMB
(MINING APPLIANCES AND METHODS)
A temporary forge—Making charcoal—Rough smelting on the mine—Misfires in blasting—To prevent loss of rich specimens in blasting—Simple retorting of small quantities of amalgam—Simple mode of ascertaining nominal H.-P. of engine—Scaling copper plates—How to supply mercury and water to mortar-boxes—Power for mills—To avoid loss in cleaning up—Iron extractor—To silver copper plates—How to make a dolly, rough windlass, puddler—A makeshift pump—Squeezing amalgam—Sluice plates—Measuring inaccessible distances—To set out a right angle with tape—Simple levelling instruments—Levelling by aneroid barometer—To determine heights—To find depth of shaft—Plan for re-using water—Cooling compound for heated bearing—Cleaning greasy plummer blocks—An excellent anti-friction compound—To clean brass—A solvent for rust—To protect iron and steel from rust—To keep machinery from rusting—Fire-lute—Rope-splicing.
pp. 140-166
APPENDIX
1. SELECTED DATA FOR MINING MEN.
To find lost part of a vein—Calculation of ore reserves—Hydraulics—Boring—Durability of ropes—Diamond drilling—Notes on timber—Laying out areas—Mensuration—Mine surveying problems—Rainfall—Belting notes—Weight and bulk of materials—Chemical elements and their symbols, &c.—Common names of chemical substances—Thermometer readings—Freezing, fusing, and boiling points—Heat values of fuels—Signs and symbols used in expressing formulas—Weights and measures—To find contents of a tank—Sizes and weights of corrugated iron sheets—Thickness and weight of sheet iron—Qualities of ropes—Atmosphere—Fresh and salt water—Velocity of falling fluids—Pressure of water—Table of squares and cubes, and their roots—Wages and interest tables.
pp. 167-193
2. AUSTRALASIAN MINING REGULATIONS pp. 194-201
INDEX pp. 203-206
GETTING GOLD
CHAPTER I
INTRODUCTORY
Gold
That this much appreciated metal is heavy to get is proved by the high value which has been placed on it from times remote to date, and that it is light to hold most of us know to our cost.
We read no farther than the second chapter in the Bible when we find mention of gold. There Moses speaks of “the land of Havilah, where there is gold”; and in Genesis, chapter xxiv., we read that Abraham’s servant gave Rebekah an earring of half a shekel weight, say 4 dwt. 13 grs., and “two bracelets of ten shekels weight,” or about 4½ ozs. Then throughout the Scriptures, and, indeed, in all historic writings, we find frequent mention of the king of metals, and always it is spoken of as a commodity highly prized.
I have sometimes thought, however, that either we are mistaken in the weights used by the Hebrew nation in early days, or that the arithmetic of those times was not quite “according to Cocker.” We read, I. Kings x. and xli., that Solomon in one year received no less than six hundred and three score and six talents of gold. If a talent of gold was, as has been assumed, 3000 shekels of 219 grains each, the value of the golden treasure accumulated in this one year by the Hebrew king would have been £3,646,350 sterling. Considering that the only means of “getting gold” in those days was a most primitive mode of washing it from river sands, or a still more difficult and laborious process of breaking the quartz from the lode without proper tools or explosives, and then slowly grinding it by hand labour between two stones, the amount mentioned is truly enormous.
Of this treasure the Queen of Sheba, who came to visit the Hebrew monarch, contributed a hundred and twenty talents, or, say, £600,000 worth. Where the Land of Ophir, whence this golden lady came, was really situated has evoked much controversy, but there is now a general opinion that Ophir was on the east coast of Africa, somewhere near Delagoa Bay, in the neighbourhood of the Limpopo and Sabia rivers. It should be mentioned that the name of the “black but comely” queen was Sabia, which may or may not be a coincidence, but it is certainly true that the rivers of this district have produced gold from prehistoric times till now.
The discovery of remarkable ruins in the newly acquired province of Mashonaland, which evince a high state of civilisation in the builders, may throw some light on this interesting subject.
The principal value of gold is as a medium of exchange, and its high appreciation is due, first, to the fact that it is in almost universal request; and, secondly, to its comparative scarcity; yet, oddly enough, with the exception of that humble but serviceable metal iron, gold is the most widely distributed metal known. Few, if any, countries do not possess it, and in most parts of the world, civilised and uncivilised, it is mined for and brought to market. The torrid, temperate, and frigid zones are almost equally auriferous. Siberia, mid-Asia, most parts of Europe, down to equatorial and southern Africa in the Old World, and north, central, and southern America, with Australasia, in what may be termed the New World, are all producers of gold in payable quantities.
In the earlier ages, the principal source of the precious metal was probably Africa, which has always been prolific in gold. To this day there are to be seen in the southern provinces of Egypt excavations and the remains of old mine buildings and appliances left by the ancient gold-miners, who were mostly State prisoners. Some of these mines were worked by the Pharaohs of, and before, the time of Moses; and in these dreadful places thousands of Israelites were driven to death by the taskmaster’s whip. Amongst the old appliances is one cut out of stone very similar to the amalgamating, or blanket-table, of a modern quartz mill (see p. 79).
The grinding was done between stones, and possibly by means of such primitive mechanism as is used to-day by the natives of Korea.
The Korean Mill is simply a large hard stone shaped as in Fig. 1, to which a rocking motion is given by manual power by means of the bamboo handles while the ore is crushed between the upper and basement stone.
Solomon says “there is no new thing under the sun”; certainly there is much that is not absolutely new in appliances for gold extraction. I lately learned that the principle of one of our newest concentrating machines, the Frue vanner, was known in India and the East centuries ago; and we have it on good authority—that of Pliny—that gold saving by amalgamation with mercury was practised before the Christian era. It will not be surprising then if, ere long, some one claims to have invented the Korean Mill, with improvements.
Few subjects in mineralogical science have evoked more controversy than the origin of gold. In the Middle Ages, and, indeed, down to the time of that great philosopher, Sir Isaac Newton, who was himself bitten with the craze, it was widely believed that, by what was known as transmutation, the baser metals might be changed to gold; and much time and trouble were expended in attempts to make gold—needless to say without the desired result. Doubtless, however, many valuable additions to chemical science, and also some useful metallic alloys, were thus discovered.
The latest startling statement on this subject comes from, of course, the wonderland of the world, America. In a recently published journal it is said that a scientific metallurgist there has succeeded in producing absolutely pure gold, which stands all tests, from silver. Needless to say, if this were true, at all events the much vexed bi-metallic question would be solved at once and for all time.
It is now admitted by all specialists that the royal metal, though differing in material respects in its mode of occurrence from its useful but more plebeian brethren of the mineral kingdom, has yet been deposited under similar conditions from mineral salts held in solution.
The first mode of obtaining this much desired metal was doubtless by washing the sand of rivers which flowed through auriferous strata. Some of these, such as the Lydian stream, Pactolus, were supposed to renew their golden stores miraculously each year. What really happened was that the winter floods detached portions of auriferous drift from the banks, which, being disintegrated by the rush and flow of the water, would naturally deposit in the still reaches and eddies any gold that might be contained therein.
The mode of washing was exactly that carried on by the natives in some districts of Africa to-day. A wooden bowl was partly filled with auriferous sand and mud, and,
I have already spoken of the mode in which auriferous lode-stuff was treated in early times—i.e., by grinding between stones. This is also practised in Africa to-day, and we have seen that the Koreans, with Mongolian acuteness, have gone a step farther, and pulverise the quartz by rocking one stone on another. In South America the arrastra is still used, which is simply the application of horse or mule power to the stone-grinding process, with use of mercury.
The principal sources of the gold supply of the modern world have been, first, South America, Transylvania in Europe, Siberia in Asia, California in North America, and Australia. Africa has always produced gold from time immemorial.
The later development in the Johannesburg district, Transvaal, which has absorbed so many millions of English capital, is now, after much difficulty and disappointment—thanks to British pluck and skill—producing splendidly. The yield for 1898 was 4,295,609, and for 1903 2,859,477 ounces—a yield never before equalled by lode-mining from one field.
In the year 1847 gold was discovered in California, at Sutor’s sawmill, Sacramento Valley, where, on the water being cut off, yellow specks and small nuggets were found in the tail race. The enormous “rush” which followed is a matter of history and the subject of many romances, though the truth has, in this instance, been stranger than fiction.
The yield of the precious metal in California since that date up to 1888 amounts to £256,000,000.
Following close on the American discovery came that of Australia, the credit of which has usually been accorded to Hargraves, a returned Californian digger, who washed out payable gold at Lewis Ponds Creek, near Bathurst, in 1851. But there is now no reason to doubt that gold had previously been discovered in several parts of that great island continent. It may be news to many that the first gold mine worked in Australia was opened about twelve miles from Adelaide city, S.A., in the year 1848. This mine was called the Victoria; several of the Company’s scrip are preserved in the Public Library; but some two years previous to this a man named Edward Proven had found gold in the same neighbourhood.
Most Governments nowadays encourage in every possible way the discovery of gold-fields, and rewards ranging from hundreds to thousands of pounds are given to successful prospectors of new auriferous districts. The reward the New South Wales authorities meted out to a wretched convict, who early in this century had dared to find gold, was a hundred lashes vigorously laid on to his already excoriated back. The man then very naturally admitted that the alleged discovery was a fraud, and that the nugget produced was a melted down brass candlestick. One might have imagined that even in those unenlightened days it would not have been difficult to find a scientist sufficiently well informed to put a little nitric acid on the supposed nugget, and so determine whether it was the genuine article, without skinning a live man first to ascertain. My belief is that the unfortunate fellow really found gold, but, as Mr. Deas Thompson, the then Colonial Secretary, afterwards told Hargraves in discouraging his reported discovery, “You must remember that as soon as Australia becomes known as a gold-producing country it is utterly spoiled as a receptacle for convicts.”
This, then, was the secret of the unwillingness of the authorities to encourage the search for gold, and it is after all due to the fact that the search was ultimately successful beyond all precedent, that Australia has been for so many years relieved of the curse of convictism, and has ceased once and for all to be a depôt for the scoundrelism of Britain—“Hurrah for the bright red gold!”
From the year 1851 to 1897 the value of the gold raised in the Australasian colonies realised the enormous amount of nearly £550,000,000. One cannot help wondering where it all goes.
Mulhall gives the existing money of the world at 2437 million pounds, of which 846 millions are paper, 801 millions silver, and 790 millions gold. From 1830 to 1880 the world consumed by melting down plate, &c., 4230 tons of silver more than it mined. From 1800 to 1870 the value of gold was about 15½ times that of silver. From 1870 to 1880 it was 16·7 times the value of silver and now exceeds it over twenty times. In 1700 the world had 301 million pounds of money, and in 1860, 1180 million pounds sterling. In 1894 the current gold was worth about £800,000,000.
The gold first worked for in Australia, as in other places, was of course alluvial, by which is usually understood loose gold in nuggets, specks, and dust, lying in drifts which were once the beds of long extinct streams and rivers, or possibly the moraines of glaciers, as in New Zealand.
Further on the differences will be mentioned between “alluvial” and “reef” or lode gold, for that there is a difference in origin in many occurrences, is, I think, provable. I hold, and hold strongly, that true alluvial gold is not always derived from the disintegration of lodes or reefs. For instance, the “Welcome Nugget” certainly never came from a reef. No such mass of gold, or anything approaching it, has ever yet been taken from a quartz matrix. It was found at Bakery Hill, Ballarat, in 1858, weight 2195 ozs., and sold for £10,500. This was above its actual value.
The “Welcome Stranger,” a still larger mass of gold, was found amongst the roots of a tree at Dunolly, Victoria, in 1869, by two starved out “fossickers” named Deeson and Oates. The weight of this, the largest authenticated nugget ever found, was 2268½ ozs., and it was sold for £10,000, but it was rendered useless as a specimen by the finders, who spent a night burning it to remove the adhering quartz.
But the ordinary digger neither hopes nor expects to unearth such treasures as these. He is content to gather together by means of puddling machine, cradle, long tom, or even puddling tub and tin dish, the scales, specks, dust, and occasional small nuggets ordinarily met with in alluvial “washes.”
Having sunk to the “wash,” or “drift,” the digger, by means of one or more of the appliances mentioned above, proceeds to separate the gold from the clay and gravel in which it is found. Of course in large alluvial claims, where capital is employed, such appliances are superseded by steam puddlers, buddles, and other machinery, and sometimes mercury is used to amalgamate the gold when very fine. Hydraulicing is the cheapest form of alluvial mining, but can only be profitably carried out where extensive drifts, which can be worked as quarry faces, and unlimited water exist in the same neighbourhood. When such conditions obtain a few grains of gold to the yard or ton will pay handsomely.
Lode, or reef mining, is a more expensive and complicated process, requiring much skill and capital. First, let me explain what a lode really is. The American term is “ledge,” and it is not
There are, however, reefs or lodes which are not persistent in depth. Sometimes the lode formation is found only in the upper and newer strata, and cuts out when, say, the basic rocks (such as granite, &c.) are reached. Again, there is a form of lode known among miners as a “gash” vein (Fig. 3). It is sometimes met with in the older crystalline slates, particularly when the lode runs conformably with the cleavage of the rock.