Dictionary:Drill

{{#category_index:D|drill}} A device for boring holes. Seismic shot-hole drills are usually mechanically driven rotary drills (see Figure D-25), often truck mounted but at times portable. They generally include the same elements as used for drilling oil wells (see drill rig and Figure D-28), a means for rotating the drill pipe and a pump for circulating a fluid (mud). Water jets, auger, spudder (q.v.) or percussion (cable) tools, and air-blast equipment are also used under certain conditions.