e; pillars
of ore; artificial pillars; caving system.

CHAPTER XII.

Mechanical Equipment

Conditions bearing on mine equipment; winding appliances; haulage
equipment in shafts; lateral underground transport; transport in
stopes.

CHAPTER XIII.

Mechanical Equipment (_Continued_)

Drainage: controlling factors; volume and head of water; flexibility;
reliability; power conditions; mechanical efficiency; capital outlay.
Systems of drainage,--steam pumps, compressed-air pumps, electrical
pumps, rod-driven pumps, bailing; comparative value of various
systems.

CHAPTER XIV.

Mechanical Equipment (_Concluded_)

Machine drilling: power transmission; compressed air _vs._ electricity;
air drills; machine _vs._ hand drilling. Workshops. Improvement in
equipment.

CHAPTER XV.

Ratio of Output to the Mine

Determination of possible maximum; limiting factors; cost of equipment;
life of the mine; mechanical inefficiency of patchwork plant;
overproduction of base metal; security of investment.

CHAPTER XVI.

Administration

Labor efficiency; skill; intelligence; application coordination;
contract work; labor unions; real basis of wages.

CHAPTER XVII.

Administration (_Continued_)

Accounts and technical data and reports; working costs; division
of expenditure; inherent limitations in accuracy of working costs;
working cost sheets. General technical data; labor, supplies, power,
surveys, sampling, and assaying.

CHAPTER XVIII.

Administration (_Concluded_)

Administrative reports.

CHAPTER XIX.

The Amount of Risk in Mining Investments

Risk in valuation of mines; in mines as compared with other commercial
enterprises.

CHAPTER XX.

The Character, Training, and Obligations of the Mining Engineering
Profession

Index

PRINCIPLES OF MINING.

CHAPTER I.

Valuation of Copper, Gold, Lead, Silver, Tin, and Zinc Lode Mines.

DETERMINATION OF AVERAGE METAL CONTENT; SAMPLING, ASSAY PLANS,
CALCULATIONS OF AVERAGES, PERCENTAGE OF ERRORS IN ESTIMATE FROM
SAMPLING.

The following discussion is limited to _in situ_ deposits of copper,
gold, lead, silver, tin, and zinc. The valuation of alluvial deposits,
iron, coal, and other mines is each a special science to itself and
cannot be adequately discussed in common with the type of deposits
mentioned above.

The value of a metal mine of the order under discussion depends
upon:--

_a_. The profit that may be won from ore exposed;
_b_. The pro