Applicability Research of 80 m Coal Pillar in 8110 Working Face in Tashan Coal Min

To determine the engineering applicability of 80 m coal pillar for 8110 coal mining face under the fault condition in Tashan Coal Mine, the influence of fault structure or without fault structure on the distribution characteristics of advance supporting stress, the stability of stop-mining pillar and the deformation of roadway are simulated. The results show that under the influence of the fault, two stress increase zones are formed in front of the working face, and the peak stress coefficients are 3.1 and 2.9 respectively. The leading supporting stress drops to the original rock stress in front of the stop-mining line of 73 m, and the overall displacement of the coal pillar drops to 0 mm from the stop-mining line of 52.4 m, and the roadway surface displacement is small. By using the surrounding rock loose tester, the loose range of the surrounding rock at the side of the stop-mining pillar in the return air roadway is measured. The results show that the loose range of the coal wall is reduced to less than 2.5 m within the distance of 25 m from the return air roadway, and the destruction of the coal wall is not obvious under the influence of mining. Surface displacement monitoring of the roadway shows that the maximum displacement of the roof and floor of the roadway means 30.6 mm, and the maximum displacement of the two sides means 17.2 mm. Engineering practice shows that good technical and economic results have been achieved by setting 80 m stop-ming pillar in 8110 working face.