Field and numerical investigations of gateroad system failure induced by hard roofs in a longwall top coal caving face

In longwall mining, hard roofs located immediately above the coal seam should not cave and cause ground control problems around the working longwall face. In this paper, comprehensive field observations and numerical simulations were used to investigate the chain pillar and adjoining gateroad failure during a longwall top coal caving (LTCC) face retreat at the Majialiang coalmine located in Shanxi, China. The results show that hard roof strata...