Study on the causes and control technology about the coal bump in multi-layered mining roadway in steep-thick coal seams

With the mining roadways with coal bumps of mining face 601 and 602 of Gansu Huating Coal Mine as the research background, through on-site in-situ stress field measurement and the mechanical analysis of the overlying surrounding rock structure, the main force source of the rock burst is identified to be a composite stress field formed by the synclinal tectonic stress field and the superimposed stress filed caused by multi-layered mining; the impact loading induced by the structural instability of overlying rock cantilever is the structural dynamic factor leading to coal bumps. Based on these results, the control technology of coal bumps is proposed with the core of "peak pressure regulation, blasting roof cutting and strong support" in the mining roadway in steep-thick coal seams. Through peak pressure regulation, the degree of stress concentration (caused by super mining) of the surrounding rock mass in the mining roadway is reduced; the blasting roof cutting can control the structural form of overlying roof cantilever; the strong support makes the surrounding rock mass in the mining roadway and the supporting materials form a support system with high strength, strong yield and integrity. Finally, it is concluded that the number of simultaneous mining working faces in Huating Coal Mine should not be more than 2, and the staggered distance between two working faces should not be less than 500 m. The blasting effect tested by the drilling stress gauge in ventilation roadway of working face 602 shows that the concentrated stress in surrounding rock mass decreases gradually. Therefore, it is considered that the control technology can effectively prevent the rock burst disaster caused by the stratified mining in steep-thick coal seams. © 2019, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.