Fracture Evolution and Accumulation and Dissipation Law of Energy During Ascending Mining

Ascending mining method is a widely used method in China for coal mine safety. To determine whether ascending mining method can eliminate or reduce the outburst risk or not in Xinzyao Mine, China, a numerical model was built by FLAC3D software to investigate the fracture evolution and accumulation and dissipation law of energy during the process of ascending mining. And a dual water blocking system was used to verify the fracture evolution obtained from the numerical model. The results show that FLAC3D model can predict the fracture evolution in overburden with a reasonable error. The height of water-conducting fractured zone of no. 14-3 coal seam is about 82.5 m, and it increases by 27 % after no. 12-2 coal seam is mined. The largest energy accumulated in no. 12-2 coal seam is about 32.5 kJ/m³ when mining it directly. The energy accumulated in no. 12-2 coal seam decreases by more than 40 % when ascending mining method is adopted. Ascending mining method can effectively eliminate the outburst risk of the upper coal seam. The research is helpful for the determination of ascending mining method and the further study of the prevention mechanism of rock burst.