Effect of faults on rockbursts hazard

At present time in Polish underground coal mining most of the mines excavates burst-prone coal seams. Especially high rockburst hazard occurs in the vicinity of the faults. This paper presents theoretical considerations about stress field around several types of faults (normal and reverse faults). Two cases of coal seam excavation around a fault are described. For both of them numerical calculations of stress field (utilising Finite Elements Method) were done. Case I shows excavation of thick coal seam on three layers with crossing through the fault system. Case II shows excavation of several coal seams on both sides of the fault. In both cases different seismic activity, connected with the geological profile of the rock mass and fault occurrence, was noticed. Finally several conclusions about minimising rockburst hazard in the vicinity of fault, basing on numerical and analytical calculations were formulated.