Effect of coal pillar width on the stress distribution law of surrounding rocks in fully mechanized top-coal caving mining face

Coal pillar width and gateway location to face result in the differences of stress redistribution and rock seam movement and importantly influence gateway stability and maintenance. According to the geological and mining technical conditions of the No. 1151(3) fully mechanized top-coal caving (FMTC) mining face in Xieqiao Mine and based on the analysis of numerical simulation and in-situ observation, the stress distribution and it's variation laws were investigated at different coal pillar widths. The results show that not only coal pillars' stress distribution laws but also coal entities' stress distribution laws are different with coal pillar width, and both stress distributions are displaced. The maintenance situation of gateway was determined on the stress distributions of coal entity and coal pillar, and the appropriate width of coal pillar is less than the critical displacing stress-width.