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 amalgam--Special difficulties, how
to overcome them 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