ABSTRACT
Drilling by rotary percussion is the most classic system for drilling blastholes, and its chronological appearance coincides with the industrial development of the nin-teenth century. The drills are usually rotary-percussive or rotary, depending upon the type of rock to be blasted, the drilling diameter and the required output. Using a truck as carrier is only done with rotary rigs and/or down the hole hammer that has high pressure compressors. The drilling principle of the rigs is based upon the impact of a steel piece that hits a utensil which transmits at the same time that energy to the bottom of the blasthole by means of the final element called the bit. When drilling with insert bits, the most common rotation speeds oscillate between 80 and 150 r.p.m. with angles between indentations of 10 to 20°. In order to have efficient drilling, the bottoms of the blastholes must be maintained clean by evacuating drill cuttings they appear.
