SOME ASPECTS OF BLASTHOLE DRILLING IN OPEN PIT MIl"ES

At most open pit mines. the mining cycle starts by drilling blastholcs. The effectiveness of drills is critical to downstream acti vities, The factors involved in the selection of drills for a particular operation are outlined. The role of blasthole diameter, blastholc angle and geological Ll:tors is given in some detail. The variables affecting the performance of both the percussive and rotary drills are discussed. The importance of aintenance, drill performance monitoring and drill positioning is included.