Pneumatic Percussion Drilling

a drilling method in which the working member is a pneumatic striker (a bottom motor that is lowered into the borehole and is powered by compressed air). It is used to drill blastholes 85–200 mm in diameter and up to 50 m deep for underground and opencut mining of minerals, and also deep petroleum, gas, and test holes 150–200 mm in diameter.

The pneumatic percussion drilling of deep holes is done using stationary rigs; blastholes are drilled using light, medium, and heavy mobile drillrigs. Compressed air is supplied to the drillrigs from mobile or stationary compressors. The dust formed during the drilling is suppressed by dedusting equipment or by an air-water mixture. The durability of the chisel, which is reinforced with a hard alloy, depends on the strength and abrasiveness of the rock and ranges from 5–10 to 500–1,000 m; the productivity of the most common drillrigs for blastholes is 20–40 m per shift (1974).