Study on Optimization of Shallow Section Coal Pillar Width of Gently Inclined Medium-Thickness Coal Seam

Abstract This paper takes a coal mine gently inclined medium-thickness coal seam as the object. Firstly, the principal stress characteristics and displacement characteristics of roadway surrounding rocks after roadway driving along goaf under section columns with different breadthes were analyzed by simulation method, and the roadway stability was evaluated to determine the reasonable breadth. The results show that when the breadth of column is 4 m, the Mohr stress circle of the pillar intersects the strength envelope and the roof and side displacement of roadway are significant; when the breadth is 6 m, the Mohr stress circle on both flanks of the pillar intersects at the strength envelope and the roof and side displacement of roadway are significant; when the breadth is 8-12 m, the Mohr stress circle of surrounding rock is separated from the strength envelope and the surrounding rock displacement meets the production needs. Therefore, it is in a stable state. 8-12 m is the reasonable width range of coal pillar. Secondly, through the actual project verification, the 8 m wide coal pillar is the most reasonable for the shallow part of the gently inclined medium-thickness coal seam.