Determination of Efficient Rotary Percussive Drilling Techniques for Strong Rocks

The authors address the problem connected with the determination of efficient rotary percussive drilling techniques with DTH hammers and present estimation criteria for their value ranges such that to ensure drilling at minimum energy content and wear of bits. The calculation formulas for drilling techniques are given, and the expediency of maximum destruction at minimum impacts per one complete turn of drill bit is proved. The upper limit of drill bit turn angle between impacts at the maximum drilling capacity and minimum energy content of fracture and wear of tungsten carbide inserts is found. The rotary percussive drilling technique with different DTH hammer models can be optimized suing the energy criterion of volumetric rock destruction and the energy content of fracture.