This article on surface drilling machines thoroughly describes rotary and percussive (both downhill and surface-mounted) drilling techniques. The discussion is limited to primary blasthole drilling as practiced in open pit, quarry, and stripping operations. Although primary blastholes usually are drilled vertically, angle holes are also common, and most blasthole drill rigs, therefore, have angle drilling capability. A few rigs are designed to drill horizontal holes for overburden removal, but these are limited in number. Most blasthole drill rigs use either rotary, percussive, or rotary-percussive drilling methods, with jet piercers used to a limited extent. Since all blasthole drills are designed for high production, they feature fast drilling, rapid tramming, quick setup, automatic drill steel handling, and rapid hoisting and lowering speeds.
Surface Subsect. 11.4 in SME Min. Eng. Handbook, V. 1, 1973, PP. 11- 24--11-56