Accounts, 169.

Administration, 161, 169, 178.

Administrative reports, 178.

Air-compression, 146.

-drills, 147.

Alteration, secondary, 24, 25, 26, 30.

Alternative shafts to inclined deposit, 63.

Amortization of capital and interest, 42.

Animals for underground transport, 134.

Annual demand for base metals, 38.

report, 179.

Artificial pillars, 121.

Assay foot, 10.

inch, 10.

of samples, 7.

plans, 1, 7.

Assaying, 177.

A value of mine, 56.

Averages, calculation, 1, 8.

Bailing, 143.

Balance sheet, 179.

Basic price, 36, 37.

value of mine, 182.

Benches, 95.

Bend in combined shafts, 59.

Bins, 84.

Blocked-out ore, 18.

Blocks, 13.

Bonanzas, origin, 28.

Bonus systems, of work, 167.

Breaking ore, 115.

Broken Hill, levels, 119.

ore-pillars, 120.

Bumping-trough, 89, 136.

Cable-ways, 135.

Cages, 132.

Calculation of averages, 1, 8.

of quantities of ore, 13.

Capital expenditure, 170.

Caving systems, 122.

Churn-drills, 92.

Chutes, loading, in vertical shaft, 86.

Classification of ore in sight, 13, 16.

Combined shaft, 58, 67, 68, 69, 70, 72.

stopes, 96, 101.

Commercial value of projects, determination, 188.

Compartments for shaft, 76.

Compressed-air locomotives, 135.

-air pumps, 141.

vs. electricity for drills, 145.

Content, average metal, determining, 1.

metal, differences, 6.

Contract work, 165.

Copper, annual demand, 38.

deposits, 1.

ores, enrichment, 30.

Cost of entry into mine, 65.

of equipment, 156.

production, 38, 39.

per foot of sinking, 64.

working, 40, 170.

Cribs, 103, 107.

Crosscuts, 86.

Cross-section of inclined deposit which must be attacked in depth, 68.

showing auxiliary vertical outlet, 66.

Crouch, J. J., 145.

Cubic feet per ton of ore, 14, 15.

foot contents of block, 13.

Deep-level mines, 60.

Demand for metals, 35.

Departmental dissection of expenditures, 171.

Deposits, in situ, 1.

ore, classes, 24.

regularity, 88.

size, 30.

structure, 24.

Depth of exhaustion, 21, 32.

Determination of average metal contents of ore, 3.

Development in early prospecting stage, 92.

in neighboring mines, 21, 31.

of mines, 58, 74, 84.

Diamond-drilling, 93.

Diluting narrow samples to a stoping width, 11.

Dip, 89.

Direct-acting steam-pumps, 140.

Distribution of values, 30.

Dividend, annual, present value, 46.

Dommeiler, 145.

Down holes, 100.

Drainage 138.

comparison of different systems, 143.

systems, 140.

Drifts, 87.

Drill, requirements, 145.

Drilling, 92, 145.

Drives, 87.

Dry walling with timber caps, 91.

Efficiency, factors of, 162.

of mass, 162.

Electrical haulage, 135.

pumps, 141.

Electricity for drills, 145.

Engine, size for winding appliances, 131.

Engineer, mining, as executive, 190.

Engineering projects, phases of, 187.

Enrichment, 27, 28, 29.

at cross-veins, 24.

Entry, to mine, 58.

to vertical or horizontal deposits, 62, 63.

Equipment, cost, 156.

improvements, 152.

mechanical, 138, 145.

Erosion, 26, 29.

Error, percentage in estimates from sampling, 1, 11.

Escape, 73.

Examination of mining property, 54.

Excavation, supporting, 103.

Exhaustion, depth, 32.

Expenditures, departmental dissection, 171.

mine, 170.

Extension in depth, 21, 22, 28.

Factor of safety in calculating averages of samples, 12.

Filling, 112.

system combined with square-setting, 111.

with broken ore subsequently withdrawn, 112.

waste, 107.

Fissure veins, 24.

Fissuring, 23.

depth, 30.

Fixed charges, 154, 170.

Flat-back stope, 98, 100, 110.

Flexibility in drainage system, 138.

Floors, 31.

Folding, 23.

Foot-drilled system of contract work, 166.

-hole system of contract work, 166.

of advance system of contract work, 166.

value, 10.

Fraud, precautions against in sampling, 7.

General expenses, 173.

Gold deposits, 1.

deposits, alteration, 29, 30.

enrichment, 28.

Hammer type of drill, 147, 148, 149.

Hand-drilling, 149.

-trucking, 133.

Haulage, electrical, 135.

equipment in shaft, 132.

mechanical, 134.

Hole system of contract work, 165.

Horizons of ore-deposits, 26.

Horizontal deposits, entry, 62.

stope, 98.

filled with waste, 108.

Hydraulic pumps, 142.

Impregnation deposits, 24.

Inch, assay, 10.

Inclined deposits to be worked from outcrop or near it, 62.

deposits which must be attacked in depth, 67.

shaft, 64.

Inclines, 65, 66, 67, 68.

capacity, 78.

Infiltration type of deposits, 24.

Intelligence as factor of skill, 163, 164.

Interest calculations in mine valuation, 43.

Intervals, level, 88, 89.

Inwood's tables, 46, 47.

Iron hat, 27.

leaching, 27.

Ivanhoe mine, West Australia, 112.

Kibble, 132.

Labor, general technical data, 176.

handling, 161.

unions, 167.

Lateral underground transport, 133.

Le Roi mine, 112.

Lead, annual demand, 38.

deposits, 1.

enriching, 27.

prices, 1884-1908, 36.

-zinc ores, enrichment, 30.

Lenses, 24.

Levels, 87.

intervals, 88, 89.

of Broken Hill, 119.

protection, 90.

Life, in sight, 44.

of mine, 157.

Locomotives, compressed-air, 135.

Lode mines, valuation, 1.

Lodes, 24.

Long-wall stope, 98.

Machine-drill, performance, 149.

drilling, 145.

vs. hand-drilling, 149.

Management, mine, 161.

Matte, 123.

Mechanical efficiency of drainage machinery, 139.

equipment, 124, 134, 138, 145.

Men for underground transport, 133.

Metal content, determining, 1, 3.

contents, differences, 6.

demand for, 35.

mine, value, 1.

price, 35, 37.

Mines compared to other commercial enterprises, 183.

equipment, 124.

expenditures, 170.

Mines—continued.

life of, 157.

metal, value of, 1.

of moderate depths, 62.

to be worked to great depths, 62, 69.

valuation, 1, 13, 21, 34, 42, 51.

Mining engineering profession, 185.

Mt. Cenis tunnel, 145.

Morgan gold mine, 26.

Normal price, 36, 37.

Obligations of engineering profession, 192.

Openings, position in relation to secondary alteration, 23, 25.

Ore, average width in block, 13.

blocked-out, 17.

-bodies, 23.

shapes, 8.

-breaking, methods, 94, 95.

calculation of quantities of, 13.

-chutes in shrinkage-stoping, 115.

-deposits, classes, 24.

determination of average metal contents, 3.

developed, 17.

developing, 17.

expectant, 17.

in sight, 16, 17, 20.

sight, classification, 13, 16.

-pillars, 118, 119.

support in narrow stopes, 118.

-shoots, 23.

weight of a cubic foot, 14.

width for one sample, 5.

Origin of deposit, 23.

Outcrop mines, 60.

Output, factors limiting, 155.

giving least production cost, 154.

maximum, determination, 153.

Overhand stapes, 96, 98, 99.

Overproduction of base metal, 158.

Oxidation, 30.

Patchwork plant, mechanical inefficiency of, 158.

Pay areas, formation, 23.

Pillars, artificial, 121.

Positive ore, 17, 20.

value of metal mine, 1.

Possible ore, 17.

Power conditions, 139.

general technical data, 176.

sources, 126.

transmission, 125, 126, 127, 145.

Preliminary inspection, 55.

Previous yield, 3.

Price of metals, 35.

Probable ore, 17, 19, 20, 21.

Producing stage of mine, 58.

Production, cost, 38, 39.

Profit and loss account, 179.

factors determining, 2.

in sight, 16.

Proportional charges, 170.

Prospecting stage of mine, 58.

Prospective ore, 19.

value, 21.

Protection of levels, 90.

Proved ore, 19, 21.

Pumping systems, 140.

Pumps, compressed-air, 141.

electrical, 141.

hydraulic, 142.

rod-driven, 142.

Ratio of output to mine, 153.

Recoverable percentage of gross assay value, 34.

Recovery of ore, 107.

Rectangular shaft, 74.

Redemption of capital and interest, 42.

Reduction of output, 158.

Regularity of deposit, 88.

Reliability of drainage system, 139.

Replacement, 24.

Reports, 56.

administrative, 178.

Resuing, 101.

Revenue account, 179.

Rill-cut overhand stope, 99.

method of incline cuts, 100.

-stopes, 98, 110.

filled with waste, 108.

-stoping, 96, 98, 99, 100, 137.

Rises, 89, 91.

Risk in mining investments, 181.

in valuation of mines, 181.

Roadways, protecting in shrinkage-stoping, 114.

Rod-driven pumps, 142.

Rotary steam-pumps, 140.

Round vertical shafts, 74.

Runs of value, 8.

test-treatment, 3.

Safety, factor of, in calculating averages of samples, 12.

Sample, assay of, 7.

average value, 9.

narrow, diluting to a stoping width, 11.

sections, 5, 6.

taking, physical details, 6.

manner of taking, 4.

Sampling, 1, 3, 4, 5, 56, 177.

accuracy, 5.

percentage of error in estimates from, 11.

precautions against fraud, 7.

Saving of fixed charges, 155.

Secondary alteration, 24, 25, 26, 30.

enrichment, 21.

Security of investment, 158.

Self-dumping skip, 77.

Sets, 91.

Shafts, 62, 64-70.

arrangement for very deep inclined shafts, 71.

compartments, 59, 78.

different depths, 60.

haulage, 129.

location, 70.

number, 72.

output capacity, 77.

shape, 74.

size, 76, 79.

Shrinkage-stope, 114, 115.

-stoping, 112.

advantages, 117.

disadvantages, 116.

when applicable, 116.

Silver deposits, 1.

deposits, enrichment, 28, 30.

prices, 38.

Sinking, speed, 80.

Size of deposit, 30.

Skill, effect on production cost, 163.

Skips, 77, 84, 132.

balanced, 129.

haulage in vertical shaft, 85.

Sollars, 109.

Solubility of minerals, 27.

Specific volume of ores, 14.

Speculative values of metal mine, 1.

value of mine, 57.

Spelter, annual demand, 38.

Square-set, 103, 104.

-set timbering, 104.

Stations, 84.

arrangement for skip haulage in vertical shaft, 85, 87.

Steam-pumps, direct, 140.

Steepening winzes and ore passes, 111.

Stope filled with broken ore, 113.

minimum width, 101.

Stoping, 89, 94.

contract systems, 166.

Storing metal, 158.

Structural character of deposit, 23.

Structure of deposit, 24.

Stull and waste pillars, 121.

support with waste reËnforcement, 120.

-supported stope, 104.

Stulls, 103.

wood, 91.

Subheading, 90.

Sublevel caving system, 122.

Subsidiary development, 84.

Superficial enrichment, 29.

Supplies, general technical data, 176.

Support by pillars of ore, 118.

Supporting excavation, 103.

Surveys, 176.

Suspense charges, 170.

Test parcels, 4.

sections, 6.

-treatment runs, 3.

Timber, cost, 77.

Timbered shaft design, 75.

Timbering, 103, 112 .

Tin, annual demand, 38.

deposits, 1.

ore, migration and enrichment, 29.

Tools, 128.

Top slicing, 123.

Tracks, 135.

Transport in stopes, 136.

Tunnel entry, 81.

feet paid for in 10 years, 82.

size, 82.

Underhand stopes, 96, 98.

Uppers, 100.

Valuation, mine, 2, 13, 21, 34, 42, 51.

of lode mines, 1.

mines, risk in, 181.

mines with little or no ore in sight, 51.

on second-hand data, 52.

Value, average, of samples, 9.

discrepancy between estimated and actual, 12.

distribution, 31.

of extension in depth, estimating, 22.

positive, of metal mine, 1.

present, of an annual dividend, 46.

of $1 or £1, payable in — years, 47.

runs of, 8.

speculative, of metal mine, 1.

Valuing ore in course of breaking, 102.

Ventilation, 72, 73.

Vertical deposits, entry, 62.

interval between levels, 88.

shafts, 62-70, 72, 85, 86.

capacity, 78.

Volume, specific, of ores, 14.

Waste-filled stope, 109.

Water-power, 126.

Weight per cubic foot of ore, 14, 15.

Weindel, Caspar, 145.

Whiting hoist, 131.

Width of ore for one sample, 5.

Winding appliances, 129.

Winzes, 89, 91.

in shrinkage-stoping, 113.

to be used for filling, 107.

Working cost, 40, 170.

inherent limitations in accuracy of, 174.

sheets, 176.

Workshops, 151.

Yield, previous, 3.

Years of life required to yield —% interest, 48.

Zinc deposits, 1.

leaching, 27.