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A drifter drill or drifter is a hydraulic or pneumatic rock or ground drill used to make horizontal holes in tunnel construction and mining. It is mounted on a feed, which is like a rail that the drill travels on or drifts. This kind of drilling procedure is also called drifting. The feed is usually attached with a flexible boom (like an arm) to a stationary or mobile unit that contains the powerpack (engine and hydraulic pump or compressor). Drifters are used in mining, construction, exploration, and natural science.
It usually consists of a percussive system and a rotative system. The percussive system strikes the drill steel, for example 2000-5000 strikes per minute, whereas the number of rotations can be, for example, 100-400 per minute. The combination of these functions enables drilling holes into rock. The excess material (cuttings) is pushed up from the bottom of the hole by means of pressurized air or water.
Early rock drills
In 1849, J. J. Couch, an American inventor from Philadelphia, received the first patent for a rock drill. It featured a drill rod which passed through a hollow piston and was thrown against the rock.