Technology and application of coordinated prevention and control of roof disaster of giant thick sandstone aquifer in Tingnan Coal Mine

The roof of the main coal seam in Tingnan Coal Mine of Binchang Mining Area is a typical thick sandstone aquifer structure, and the multi-dynamic disaster outburst problem of rock burst, water damage and gas. Based on the analysis of the field measured data, two typical disaster chains of' rock burst-water disaster and rock burst-gas disaster' in Tingnan Coal Mine were obtained. The disaster-causing mechanism of the disaster chain was studied through laboratory tests, and the principle of coordinated prevention and control of disasters was formulated. The coordinated prevention and control methods of roof disasters in extremely thick sandstone aquifers were designed, including two stages of pre-mining and mining, as well as the overall prevention and control of source chain breaking and systematic prevention and control of isolated chain breaking, and were applied in Tingnan Coal Mine. The results show that with the increase of impact amplitude, the ultimate bearing capacity of dynamic damaged coal and rock mass decreases, and the impact leads to the damage and weakening of roof, which communicates with the thick sandstone aquifer. The porosity of sandstone samples after strong impact is 8.23 %, which is 34.48 % higher than that without impact. The occurrence of rock burst increases the fracture of rock mass and provides a channel for gas escape. Through the cooperative prevention and control technology of roof disaster in extremely thick sandstone aquifer, the average resistance of the support is 35.03 MPa, and there is no obvious stress surge. The water inflow of the working face is stable at 250~280 m³/h, and the methane emission fluctuates at the level of 0.2 %. The research can provide basic theoretical support for the prevention and control of multi-dynamic disasters in coal mines in Binchang mining area, help to achieve efficient prevention of coal mine disaster risks, and promote the progress of multi-disaster collaborative prevention and control technology.