Research On The Technology Of Outburst Prevention For Rock Cross-cut Coal Uncovering Under The Igneous Intrusived Area

Coal and gas outburst has been one of the most significant disasters, which often causes casualties and property damage. Even if it does not cause casualties, it will increase the gas emission inside roadway thus causes higher values transfinite which threaten the safety of coal mine. In the process of rock cross-cut coal uncovering, the probability of coal and gas outburst increases because of special storage condition and geologic structure. As a result, significant number of countries, researchers and coal mines continue researching for advanced technology of outburst prevention, in order to cut through coal seam safely.Haizi Coal Mine is a typical example that is influenced by igneous rock invading. Igneous rock invades from the5th coal seam of Haizi Coal Mine and the maximum gauge can reach to170m, which cover the most areas in mine. Under the pressure of roast and gravity by igneous rock, regulation of gas occurrence in the underlying seam becomes abnormal. In history, coal and gas outburst frequently happened because of igneous rock invading, which caused serious casualties and property damage. Also, higher values transfinite happened, which threaten the safety of coal mine.In mining area Ⅱ32of Haizi Coal Mine, the main cross-hole is covered by igneous rock which is140m in average. In order to cut through coal seam of9,8coal seam group in Ⅱ32main cross-hole safely and successfully, firstly, it analyzes the relevant factors of causing coal and gas outburst according to damage mechanics theory and solid-fluid coupling theory; Secondly, it coMPares and analyzes differences of stress distribution in front of awaiting uncover coal in the condition of igneous rock and sandstone by numerical simulation software COMSOL-Multiphysics; Finally, it uses intensive pre-pumping drilling to pump gas and low pressure hydraulic flushing in order to clear the danger of coal and gas outburst in awaiting uncover coal.According to status that the stress concentration area in front of the thick igneous rock invading area and stress peak is higher than situation that overlying is sandstone, coal and gas out burst hazard in awaiting uncover coal will increase. The relevance parameter influenced by igneous rock is definitely higher than other mining area. After intensive pre-pumping drilling and low pressure hydraulic flushing to awaiting uncover coal, the pure flow increased to26.5%-43.8%,the concentration of the gas increased to 84.4%-91.7%;the rest gas pressure of awaiting uncover coal is0.3MPa,0.22MPa; the rest content of gas is5.23m3/t,5.21m3/t. The whole gas drainage efficiency reaches to55.7%. The result indicates that the series of solutions have positive effect, it can successfully cut through coal seam.