air-drill

The most satisfactory electric drill produced has been the Temple drill, which is really an air-drill driven by a small electrically-driven compressor placed near the drill itself.

Principles of Mining Valuation, Organization and Administration Herbert Hoover 1919

This trench is cut with a hammer and moil, or, where compressed air is available and the rock hard, a small air-drill of the hammer type is used.

Principles of Mining Valuation, Organization and Administration Herbert Hoover 1919

The actual work performed by the standard 3-3/4-inch air-drill probably does not amount to over two or three horse-power against from fifteen to eighteen horse-power delivered into the compressor, or mechanical efficiency of less than 25\%.

Principles of Mining Valuation, Organization and Administration Herbert Hoover 1919

Compressed air has a distinct place for minor pumping units, especially those removed from the shaft, for they can be run as an adjunct to the air-drill system of the mine, and by this arrangement much capital outlay may be saved.

Principles of Mining Valuation, Organization and Administration Herbert Hoover 1919

I want you to turn on them the air-drill pipe as soon as they break through.

Ridgway of Montana (Story of To-Day, in Which the Hero Is Also the Villain) William MacLeod Raine 1912

He doesn't know the difference between an adit and an air-drill.

Rimrock Trail 1906

Casey was in jail, naturally; but he didn't care much about that so long as he owned a head with an air-drill going inside.

The Trail of the White Mule B. M. Bower 1905

Beyond that he was good-naturedly willing to talk of the stupendous undertaking over which he was presiding, expatiating enthusiastically upon air-drill performance, porphyry shooting, the merits of various kinds of high explosives, deep-mine ventilation, and the like.

Branded Francis Lynde 1893

Brawny, half-naked forms were already wielding pick and shovel amid the masses of rock just loosened, a powerful air-drill was being placed in position for another attack upon the wall of tough rock, and

The Copper Princess A Story of Lake Superior Mines Kirk Munroe 1890