Prevention of rock burst during initial mining of deep overhand mining island working face

Abstract

Taking No.1310 working face of Xiaoyun Coal Mine as the engineering background, the initial breakage and instability position of the suspension roof was determined by calculation, the large amount of bending strain energy released was analyzed when the hard roof is broken, and FLAC3D numerical simulation was used to analyze the mining stress changing during the initial mining of the deep overhand mining isolated island working face. Based on the energy released by the breakage of the suspension roof and the stress concentration coefficient during initial mining exceeding the critical value of rock burst, it was judged that the rock burst was likely to occur during the initial mining of the deep isolated island working face. By taking comprehensive pressure relief measures such as large-diameter borehole pressure relief combined with roof deep hole presplit blasting and other comprehensive pressure relief measures, the impact risk in the initial mining stage was prevented and controlled. The results show that the weakened zone formed by the pressure relief drilling destroys the bearing structure of the coal body, which obviously reduces the stress of the shallow coal body near the roadway, and the stress peak shifts to the deep part of the coal body. Blasting damages the roof, releasing or transferring the elastic energy accumulated in the hard roof in advance, so as to reduce the possibility of rock burst in the initial mining stage of isolated island working face.

Keywords

• isolated island working face
• overhand mining
• rock burst during initial mining
• energy analysis
• borehole pressure relief
• deep hole presplit blasting