Alfred G. (Alfred George) Lock.

Gold, its occurrence and extraction : embracing the geographical and geological distribution and the mineralogical characters of gold-bearing rocks; the peculiar features and modes of working shallow placers, rivers, and deep leads; hydraulicing ... a bibliography of the subject; and a glossary of E online

. (page 1 of 142)
Online LibraryAlfred G. (Alfred George) LockGold, its occurrence and extraction : embracing the geographical and geological distribution and the mineralogical characters of gold-bearing rocks; the peculiar features and modes of working shallow placers, rivers, and deep leads; hydraulicing ... a bibliography of the subject; and a glossary of E → online text (page 1 of 142)
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pi* REESE LIBRARY

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UNIVERSITY OF CALIFORNIA,







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GOLD:

ITS OCCURRENCE AND EXTRACTION.



GOLD:



ITS OCCURRENCE AND EXTRACTION.

EMBRACING

THE GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION AND

THE MINERALOGICAL CHARACTERS OF

GOLD-BEARING ROCKS ;

THE PECULIAR FEATURES AND MODES OF WORKING
SHALLOW PLACERS, RIVERS, AND DEEP LEADS ;

HYDRAULICING ;

THE REDUCTION AND SEPARATION OF
AURIFEROUS QUARTZ;

THE TREATMENT OF COMPLEX AURIFEROUS ORES CONTAINING

OTHER METALS;

A BIBLIOGRAPHY OF THE SUBJECT ;

AND

A GLOSSARY OF ENGLISH AND FOREIGN TECHNICAL TERMS.

BY

ALFRED G. LOCK, F.R.G.S.

I 4

WITH SIX DOUBLE-PAGE MAPS, AND 185 ENGRAVINGS IN THE TEXT.






NIVERSITY



LONDON :

K. & F. N. SPON, 1 6, CHARING CROSS.

NEW YORK: 44, MURRAY STREET.

1882.



INTRODUCTION.



THE possession of gold has been the aim of all races, in all ages, and
of all classes of society. The quest of gold has led men to the ends of
the earth, and has been the primary inducement in colonizing hitherto
unknown districts. Without the great gold discoveries of the last 30
years, our commerce could not have attained its present vast proportions.
The importance of the metal especially to all English-speaking peoples
cannot be exaggerated, and every year adds to this importance. On the
other hand, the supply shows a waning tendency. The enormous, easily-
worked, alluvial deposits of Australia, California, and Siberia, have been
exhausted over large areas, though many similar deposits must yet remain
undiscovered. In the more difficult operations of extracting gold from
mineral veins and complex ores, reliable evidence from all parts of the
world shows that most of the processes at present in use, or the methods
of carrying them out, are far from satisfactory, as they entail the loss,
on the average, of one-quarter to one-third of the gold present in the
material operated upon. ' *

These facts point unmistakably to the necessity for studying the
conditions under which gold occurs, so that new fields may be opened up
to supply the places of those which have been worked out ; and they
make it the duty of every intelligent miner to avail himself of the
experience of others, in endeavouring to reduce the cost of extracting the
gold, and especially the loss of metal in conducting his operations, to the
lowest possible figures. Recent geological explorations have shown that
gold is abundantly present in formations which it was authoritatively
stated could never prove to be auriferous, and in the light of our present
knowledge it would not be safe to exclude any geological series from the
possibility of being gold-bearing. Gold reveals its presence in the earth's
crust far less readily than other useful minerals, and many a gold-field
has been passed over by generations of men before its riches were dis-
covered. Hence the necessity for intelligent search.

It seemed to the author of this volume that a great step towards
aiding the advance of the gold industry would be to bring together in a
concentrated form all available existing information on the subject. The

b 2



VI INTRODUCTION.

handsome work written some years ago by John Arthur Phillips, F.R.S.,
the well-known metallurgist, has long been out of print and very scarce,
and many new discoveries and inventions have since been made. Gold-
mining too has taken a great start of late, many millions of fresh capital
having found employment in this sphere. Hence there would appear to be
ample room for an exhaustive book on the subject. How far the present
work may fulfil the required conditions must be left to the reader's judg-
ment. The cordial assistance received by the author from all who had
knowledge to impart will be evident from a perusal of the following
pages.

It remains to pay a tribute of hearty thanks to the many kind con-
tributors mentioned in the following list, from whose labours the book
derives whatever value it may have.

A. B. Ainsworth, C.E., Alexandra, Victoria, for geological and other
information relating to his district.

J. Allen, Warden in Marlborough district, New Zealand, for numerous
photographs illustrating the operations adopted in his district
(Fig. 46 and Frontispiece, pp. 884-7), and f r much detailed informa-
tion.

Appleby Brothers, Engineers, London, for drawings of machinery.

George Ashcroft, Railway Manager, Wellington, New Zealand, for
account of his patent gold-saving machine.

Melville Atwood, M.E., F.G.S., San Francisco, California, for various

papers by him.
Bailey, Wilson, & Co., London, for information about certain American

appliances for gold.
H. H. Barton, Mabel Pyrites Works, Ravenswood, for details of his

process, and general information and drawings.

Rivett Henry Bland, F.G.S., Manager of the Port Phillip and Colonial
G. M. Co.'s works at Clunes, for most diffuse information concerning
the methods adopted under his management, the success of which
places his works second to none in the world.

S. A. Brunning, Agent-General's Department for Victoria, London, for
loan of various books, papers, and reports relative to that colony.

Thomas Buckland, Charters Towers, Queensland, for information con-
cerning his district, and for drawings forwarded by the Langlands
Foundry Co., Melbourne.

The Hon. Horatio C. Burchard, Director-General of the United States
Mint, Washington, for the annual Reports of his Bureau.

E. H. Carew, Warden in the Otago district, New Zealand, for account of
machinery used in his district.



INTRODUCTION. Vll

C. W. Chapman, United Pyrites Co., Sandhurst, Victoria, for an account

with drawings of their method of working Plattner's chlorination

process, and other information.
John Coles, F.R.A.S., F.R.G.S., Map Curator Royal Geographical Society,

without whose cheerfully rendered assistance in all matters of exact

geography it would have been impossible to compile the maps

illustrating this volume.
The Directors of Columbia College, New York, for the ' School of Mines

Quarterly.' >

Thomas Couchman, Secretary for Mines and Water Supply, Melbourne

Victoria, for official map of Victoria, Reports of Progress, and

numerous valuable Reports.
W. G. Dallas, F.L.S., Assistant-Secretary of the Geological Society, for

the kind and hearty assistance he always so willingly rendered.
Chevalier Dalla Vedova, Secretary-General ' Societa Geografica Italiana,'

Rome, Italy, for information regarding, and map of, the gold-mines of

that country.
Phillip Davies, 135, Pitt St., Sydney, N.S.W., for description of curious

quartz veins, and sketches by De Lacy Richards, R.N. (Fig. 99,

P- 945).
G. F. Deetken, Auburn, Placer Co., California, for references to works.

Charles S. Dicken, Secretary Queensland Government Office, London,
formerly Gold-Fields Warden and P. M. at Ravenswood, &c., for loan
of papers, and introductions to several persons in the colony.

F. Elwyn, Deputy Provincial Secretary of British Columbia, Victoria B.C.,
for map of that colony showing gold-fields, and reports on them.

Martin Ferreiro, General Secretary ' Sociedad Geografica,' Madrid, Spain,
for very valuable books on, and map showing, the gold deposits of
that country.

Edwin Field, Manager Costerfield Gold Mining Co., Victoria, for answers
to circular questions and for sketch of special apparatus.

George J. Firmin, The Wildernesse, Norristown, Pennsylvania, for
information relating to the United States.

Montague J. M. Flint, F.R.G.S., Gunnersbury, for map showing gold
deposits of Dutch Guiana.

Joseph Flude, Superintendent of Laboratories, School of Mines, Ballarat,
Victoria, for account of pyrites-furnace (p. 1113).

Dr. Clement Le Neve Foster, B.A., F.G.S., H.M. Inspector of Mines in
N. Wales, for cordial assistance and advice, most materially con-
tributing to the value of the work.

The Hon. Malcolm Eraser, Surveyor-General Western Australia, for map
of that colony, and account of the gold discovered.



Vlll INTRODUCTION.

Thomas Gibb, F.C.S., A.R.S.M., of the Grange Metal Extracting Works,

Jarrow-on Tyne, for information relating to separating methods used

on the Tyne.
Edwin Gilpin, Jun., A.M., F.G.S., Inspector of Mines, Halifax, Nova

Scotia, for important information respecting the geology, and re-
duction processes, of his State, and for drawing of contorted vein

(Fig. 119, p. 997).
Golden State and Miners' Iron Works, 237 to 25 1, First St., San Francisco,

for a sheet of drawings of machinery.
Francisco Vidal y Gormaz, State Hydrographer, Santiago, Chili, for the

trouble taken by him in procuring official maps and information

respecting Chili.
Grafton & Avigdor, Great George St., for papers relative to gold-mines

in Canada.
Frank Guinness, Warden and P. M., Collingwood gold-fields, Nelson, N.Z.,

for geological and other information relating to his district.
J. D. Hague, of the United States Geological Survey, for information

respecting the gold industry of the U. S.
E. Hahn, Hamburg, Germany, for the loan of papers relative to the

El Callao mine (p. 267).
Prof. Henry G. Hanks, F.R.M.S., State Mineralogist, San Francisco,

California, for papers on occurrence of gold in California.
Edward Harrison, Warden of Grant district, Victoria, for information

about his district.
Dr. F. V. Hayden, Hon. Cor. F.R.G.S., United States Geological Survey,

Washington.
Dr. James Hector, C.M.G. F.R.S., Director of the Geological Survey,

Wellington, New Zealand, for his liberal and valuable present of

books and reports which were otherwise unprocurable.
Henry F. Holt, Secretary Royal Asiatic Society, for article about gold in

China.
Major Jed. Hotchkiss, Staunton, Virginia, U. S. America, for information

regarding his State.
A. W. Howitt, F.G.S., Warden and P. M. Sale gold-field, Gippsland,

Victoria, for reports and papers respecting his district.
James Irvine, F.R.G.S., Liverpool, for information on the West Coast of

Africa.
Robert L. Jack, F.R.G.S., F.G.S., Director of the Geological Survey,

Brisbane, Queensland, for map of the colony showing the gold-fields,

and for various reports concerning its geology, &c.
James Jackson, F.R.G.S., Archiviste-Bibliothecaire de la Societe de

Geographic, Paris, for French literature on the subject of gold in

France.



INTRODUCTION. IX

J. Jewell, M.E., M.M.S., Manager of the Aruba Island gold-mines, for

descriptions of long-torn and torpedo used in Dutch Guiana.
W. Rupert Jones, Librarian Geological Society, for assistance when

referring to books in his library.
Prof. Judd, F.R.S., F.G.S., School of Mines, for his pamphlet on the

Schemnitz district.
The Kapanga (New Zealand) Gold Mining Company, Limited, for answers

to circular of questions.
Walter Kennaway, Secretary to Agent-General's Department for New

Zealand, for loan of various reports and papers on that colony.
Knight & Co., Sutter Creek, for drawings of machinery.

New Koh-i-Noor Quartz Mining Company,Ballarat, Victoria, for descrip-
tion and drawings of their reduction works, in answer to circular
of questions.

H. Thomas Lock, Photographer, New Zealand, for some very fine photo-
graphs of gold mining, and gold-saving appliances used in that
colony.

John Lynch, Mining Surveyor, Smythesdale, Victoria, for information
respecting his district.

Malter, Lind, & Co., 189, Broadway, New York, and 419, California St.,
San Francisco, for descriptions and illustrations of gold-milling
appliances.

William Martineau, M.I.C.E., for drawing of stamp suited to mule
power.

Clements R. Markham, C.B., F.R.S., Secretary R. Geogr. Soc.,for informa-
tion about gold in Peru.

Farnham Maxwell-Lyte, F.C.S., F.I.C., for his pamphlet on metallurgical
processes.

C. W. Minchin, for information respecting Bolivia, and for map showing

its gold deposits.
Morey and Sperry, 145, Broadway, New York, for descriptions, drawings,

and electrotypes of machinery.
Alexander Murray, Survey or- General of Newfoundland, for his paper

on that colony.

Reginald A. F. Murray, F.G.S., Geological Survey, Melbourne, Victoria,
for information regarding the geology of that colony.

Thomas W. Newton, F. R. Hist. Soc., Librarian School of Mines, for
assistance when referring to books at his library.

E. O'Malley, Clarence Cottage, Grey Street East, Melbourne, Victoria,
for details concerning his process.

Sir Archibald Michie, late Agent-General for Victoria, for information
regarding gold in that colony.



X INTRODUCTION.

John Patterson, 9, Inverness Terrace, Kensington Gardens, for information

concerning his pneumatic stamps (p. 1023), and many other useful

statements.
Mariano Felipe Paz Soldan, Hon. Cor. F.R.G.S., Lima, Peru, for

exhaustive information respecting that country.
John R. Peny, M. A., Exeter College, Oxford, for drawing of his hydraulic

gravel-elevator (p. 990).
Captain Bedford C. T. Pirn, R.N., F.R.G.S., for information respecting

Central America.
The Chairman, Secretary and Manager of the Placerville Gold Quartz Co.,

for drawings of their apparatus, and replies to questions.
E. H. Plant, Charters Towers, Queensland, for full information regarding

the geology of, and the appliances in use in, his district.
Pleasant Creek Cross Reef Quartz Mining Company (Stawell, Victoria),

for answers to circular of questions.
Dr. Thomas Pollard, State Commissioner of Agriculture, Richmond,

Virginia, U. S. America, for information regarding that State.

W. Delisle Powles^ , - , r , , .

_, I Old Broad St., City, for loan of valuable reports and

r* r\ $ ' ( papers respecting gold in the U. S. of Colombia.

Ed. Probert, Director in Nevada of the Richmond Mining Company, for
information respecting the process adopted by that Company.

Queen's Birthday Company, Dunolly, Victoria, for answers to circular of
questions.

Henry H. E. Ralfe, Receiver of Gold Revenue, New Zealand, for descrip-
tion and sketch of sluicing box used in sea-beach claims (p. 893).

William Rasche, 55, Elizabeth St., Melbourne, for details of his direct-
acting battery.

Prof. Rossiter W. Raymond, United States Commissioner of Mining
Statistics, for replies to numerous questions relating to the American
gold-industry.

W. H. Revell, Warden in Marlborough district, New Zealand, for
drawings and description of method of working sea-beach
"claims in New Zealand, and of the gold-saving tables in creeks
(p. 904).

H. W. Robinson, Warden in Otago district, New Zealand, for drawings
and description of covered tail-races (p. 879).

Henry Resales, F.G.S., long Manager of the late Walhalla G. M. Co.,
Victoria, for an account of his process for pyrites (pp. 1119-25), and
for many suggestions and facts.

George Rouch, M.E., for translations of Spanish documents, and notes on
Spanish gold weights.



INTRODUCTION. xi

F. W. Rudler, F.G.S., M.A.I., School of Mines, for his readiness to give

information and assistance whenever applied to.
Edward Caldwell Rye, F.Z.S., M.E.S., Hon. F. Neth. Geog. Soc.,

Librarian Royal Geographical Society, whose extensive knowledge

of books of travel was at all times placed at the author's service, and

conspicuously aided him in dealing with the geographical distribution

of gold.

Howard Saunders, F.R.G.S., for information about gold in Peru.
Adolph Schmitt-Manderbach, Biebrich-am-Rhein, for particulars of his

spiral sieve.
The Hon. the Chief Secretary of South Australia, Adelaide, for map

showing gold-fields in that colony and reports respecting them.
The Hon. the Chief Secretary, Sydney, New South Wales, for map of

that colony showing the gold.
Alfred R. C. Selwyn, F.G.S., Director-General Geological Survey of

Canada, Montreal, for numerous reports and pamphlets concerning

that colony.

F. A. A. Simons, for information about Africa.
William Skey, Analyst to the Geological Survey of New Zealand, for

copies of his very valuable papers read before scientific Societies in

New Zealand, and his remarks on them.
Walter A. Skidmore, U. S. Deputy Mineral Surveyor and Assayer, San

Francisco, California, for information regarding certain processes in

the United States.
W. H. J. Slee, Inspector of Mines, New South Wales, for names of books

and papers to consult relative to that colony.
Joseph V. Smedley, M.A., F.R.G.S., Chairman of the Aruba Gold Mining

Co., for information regarding Aruba, W. Indies.
W. *B. Smith, Paramaribo, Surinam, for map of French Guiana showing

the position of its gold-fields.
Ben. B. Spargo, Jun., Warden of Gibbo subdivision, for an account of

operations in his district.
Thos. Lett Stahlschmidt, Agent-General for British Columbia, for

information respecting that colony.

George W. Stuart, Montagu, Nova Scotia, for information on that colony.
Frank Taylor, Sandycroft Foundry Co., Hawarden, Chester, for drawings

and descriptions of machinery.
Prof. G. H. F. Ulrich, F.G.S., Consulting Mining Geologist and Engineer,

late Senior Field-Geologist to the Geological Survey of Victoria, for

papers, letters, and other valuable contributions too numerous to

detail.
Robert B. White, Manager Frontino and Bolivia Gold Mining Co.,

Limited, for pamphlet on gold in U. S. of Colombia.



Xll INTRODUCTION.

J. D. Whitney, Hon. Cor. F.R.G.S., State Geologist U. S. of America,

for valuable information respecting the geology of gold in that

country.
C. S. Wilkinson, F.G.S., Geological Surveyor in charge, Sydney, New

South Wales, for various papers and pamphlets giving information

regarding his colony.
John Widdecombe, Director Aruba Agency Company, Limited, for loan

of books and papers.
J. Brooks Wright, Glasgow, for the loan of papers respecting gold in

India.
Samuel Yardley, Secretary New South Wales Government Agency, for

Harcus' ' South Australia,' and the loan of numerous Government

Reports and papers on the Colonies of Australia.
Lt- General E. Wray, Woolwich, for reports of African Gold Coast

Company, Limited.
J. M. Ziegler, Hon. Cor. F.R.G.S., Bale, Switzerland, for information

respecting that country.

Where all have been so liberal with help, it may seem somewhat
invidious to particularize, but special acknowledgment is due to E.-Delmar
Morgan, F.R.G.S., Dr. Foster, Prof. Ulrich, Dr. Hector, and Messrs. Allen,
Bland, Coles, Couchman, Gilpin, Resales, Rye, and Selwyn. Finally, the
tedious labour of editing the work and seeing it through the press
devolved upon my son, Charles G. Warnford Lock, who came to the
task fresh from editing Messrs. Spon's new Encyclopaedia of Manufactures
and Raw Materials, and whose knowledge of languages, and experience
of mining in Hungary, Turkey, and Iceland, were of great assistance.



ALFRED G. LOCK.



MERTON LODGE, COWLEY ROAD, BRIXTON.
November 9, 1882.



CHAPTER I.

GEOGRAPHICAL DISTRIBUTION, pp. i to 745.

In this chapter the world is divided into 6 sections, each illustrated by a map, and
the sections are again separated into countries, as indicated on pp. 1-2. In describing,
in turn, every country which produces or has produced gold, or is known to possess
gold-bearing rocks, attention is given to the exact localities where the metal or rocks
exist, to the general geological features of each field, to the characters of the ores, to
the native methods employed for extracting the gold, to ancient and modern statistics
of the yield, to the laws and regulations affecting the industry, to the cost of necessaries
and rate of wages, to the labour question and the climate, to traditions indicating
past or hidden sources of wealth, and, in short, to every point which seems to throw
any light upon the subject.



CHAPTER II.
GEOLOGICAL OCCURRENCE AND MINERALOGICAL ASSOCIATION, pp. 746 to 845.

This chapter embraces three separate subjects : (i) A summary of the theories
advanced during the last 20 years to account for the origin and formation of gold in
veins and alluvial deposits, and for the occurrence of nuggets ; (2) a systematic epitome
of the geological formations in which gold has been found, showing its very wide dis-
tribution in strata of almost all ages ; (3) a catalogue of the metallic and other minerals
associated with gold and auriferous rocks, with remarks upon the manner in which the
ores are affected by them.

..

CHAPTER III.
SHALLOW PLACERS AND LIVE RIVERS, pp. 846 to 907.

Definition, importance, formation, decline, characters, sections of strata, favourable
and unfavourable conditions, influence of bed-rock, object in placer-mining ; principle
of gold-washing, pans and panning, removing iron-sand, batea, horn spoon, cradle or
rocker, Burke rocker, toms, sluices, box-sluices, false bottoms and riffles ; block and
zigzag riffles, Rowland's riffle ; amalgamation, copper plates ; cleaning up, multiple



XIV SYNOPSIS OF CONTENTS.

sluices, under-current sluice, Evans and Frey's sluice, ground-sluice ; working results ;
puddling-machines ; whips and whims ; draining the workings, Californian pump,
Chinese pump, syphons ; modes of working alluvial deposits : stripping, working by
shafts and drives, paddocks and paddocking, working reef-washes, sluicing, covered
tail-races ; dry washing ; river-mining : lifting rivers, dredging ; beach-mining ; flume
for transporting timber ; cost of alluvial mining ; cement, its occurrence, stamping,
Drake's cement-mill, Cox's pan, yields ; saving fine, flour- and float-gold, water,
copper plates, McDougalPs plan, Sublett's plan, flycatching; yields of shallow
placers.



CHAPTER IV.
DEEP LEADS OR DEAD RIVERS, pp. 908 to 949.

Definition ; formation ; sections of strata, showing leads of Miocene, Upper
Pliocene, Middle Pliocene, and Lower Pliocene ages, some covered by one or more
streams of basaltic lava : modes of working, ventilation, apparatus ; yields.



CHAPTER V.

HYDRAULICING, pp. 950 to 996.

Origin, advantages, essential conditions, water-supply ; miners' " inch," securing
water-supply, dams and reservoirs, ditches, flumes, pipes, nozzles ; tunnels and shafts ;
sluices, water consumed, erecting sluice, paving, under-currents, drops, grizzlies, general
arrangement ; tail-sluices ; blasting ; conduct of operations ; working results ; losses ;
seam diggings ; crushing process ; hydraulic elevators ; booming ; utilizing river-
currents for sluicing ; drawbacks to hydraulicing, destruction of agricultural land, and
silting up of rivers and bays.



CHAPTER VI.
AURIFEROUS VEINSTUFF, pp. 997 to 1101.

Sections of veins. Treatment of the veinstuff : crushing ; stamping, foundations,
frames, mortars or coffers, screens or gratings, dies or false bottoms, stamps, weight of
stamps, height of drop, speed, order of drop, character of blow, tappets or collars, guides,
cams or wipers, cam-shaft, props or studs, feeding, automatic feeders, water, tables of
dimensions and duty of stamps, special forms of stamp (Dunham's, Fisher's,
Patterson's, Sholl's) ; pulverizers (Rowland's, Jordan's, Lucop's, Thompson's). Arresting
the metal : general principles, ways of using mercury, amalgamated plates ; amalga-
mating pans, general details, Berdan's pan, Britten's pan, Chilian mill, Denny &
Roberts' pan, Dickson's amalgamator, Hepburn & Peterson's pan, Horn's pan,
Hungarian bowl or Tyrolese mill, Hunter's rubber, Jordan's pan, McCone's pan,
Patton's pan, Peek's amalgamator, Readwin's amalgamator, Wheeler's pan, Wheeler
& Randall's pan ; blanket-tables ; roasting quartz. Treatment of blanket-sand :



SYNOPSIS OF CONTENTS. XV

barrel-amalgamation. Treatment of tailings : definition and general principles ;
settlers ; sizers, sieves, labyrinths, pyramidal boxes, triangular double troughs ; con-
centration, -percussion-tables, rotating tables, buddies, Bradford's jig, Denny's
concentrator, Dodge's concentrator, Frue vanner, Hendy's concentrator, Imlay con-
centrator. Complete mills : Kite Mining Co.'s, Placerville Co.'s, Port Phillip Co.'s,
Rio Grande.



CHAPTER VII.
AURIFEROUS ORES, pp. 1102 to 1151.

Definition. Composition of ores : series of assays. Association of the gold.
Treatment of complex ores. Antimonial ores : their characters ; Herrenschmidt's
furnace, Cosmo Newbery's process for recovering the antimony, Designolle's process.
Arsenical ores : their characters ; Chapman's process, Flude's furnace, Port Phillip
Co.'s furnace, revolving furnaces, Resales' process. Bismuth. Cobalt and Nickel.
Copper ores : characters ; Claudet's process, Henderson's process, Hollway's process,
Hunt & Douglas' process, Mears' process, Monnier's process, Paul's process,
Plattner's process, Washoe process. Iron-ores : characters ; Denny's drop-furnace.
Lead ores : characters ; Austrian process, Richmond process. Silver : separation



Online LibraryAlfred G. (Alfred George) LockGold, its occurrence and extraction : embracing the geographical and geological distribution and the mineralogical characters of gold-bearing rocks; the peculiar features and modes of working shallow placers, rivers, and deep leads; hydraulicing ... a bibliography of the subject; and a glossary of E → online text (page 1 of 142)