A METHOD EMPLOYED IN LONG-HOLE DRILLING AND A DRILL ROD SYSTEM

摘要

PCT No. PCT/FI83/00074 Sec. 371 Date Jul. 19, 1984 Sec. 102(e) Date Jul. 19, 1984 PCT Filed Nov. 29, 1983 PCT Pub. No. WO84/02158 PCT Pub. Date Jun. 7, 1984.Method and apparatus for Percussive drilling, in which a drill rod is selected with dimensions such that cross-sectional areas of an inner channel within the rod for flushing medium, and of an outer channel formed between the rod and material being drilled, are substantially equal, so that flow resistance of the drill particles and consumption of flushing powder are reduced.