Study on section coal pillar size in gently inclined and extra-thick coal seam

ZHANG Jie; YANG Tao

doi:10.11799/ce201710009

Abstract：Due to the complex geological conditions of No. 11 mining district of fully mechanized top-coal caving face in Wangwa Coal Mine, the reasonable parameter of section coal pillar is important to guide the safety production. According to t stress measurement and borehole imaging in the coal pillar, the internal damage of coal pillar is revealed. The result indicates that, the peak stress along the strike of coal pillar appears at 10m ahead of the working face, and the failure region is within 3m along the dip of coal pillar, and the peak stress apears around 6m in the coal pillar. Further, the stress distribution rules of coal pillars with different size are analyzed by numerical simulation under the same production condition, which shows that the coal pillar gets some elastic region when the coal pillar width increases to 26m, with the increase of the coal pillar width, the elastic region width also increases, and when the coal pillar width increases to 29m and 32m, it can guarantee the stability of coal pillar and the roadway deformation is within permitted range. According to the results of field monitoring and numerical simulation, reasonable size of the section coal pillar is 30m. Compared with the previous pillar, the research result greatly reduces the pillar width and improves the recovery rate of coal resources.