Influence of Contact Time between Buttons of Roller Bits and Rock on Indicators of Rock Fracture

Selection of efficient methods and means for rock fracture is one of the major challenges the coal mining industry is faced with. For rocks of high hardness, the most efficient fracture method is drilling with button bits. The main objective of the implemented research is determining the actual time of contact between bit buttons and rock and the required time of contact to reach the destructive load with respect to various influences.