Distribution Characteristics of Coal Spontaneous Combustion and Gas Explosion Hazard Area in Goaf of Steeply Inclined Thin Coal Seam

In order to improve the comprehensive control effect of gas and coal spontaneous combustion under the condition of pseudo-inclined mining of steeply inclined seam, COMSOL 5.2 software is used to establish the “three zone” distribution model of spontaneous combustion during coal mining area based on coal spontaneous combustion “three zone” division standard and gas explosion triangle. The porosity, gas concentration and temperature parameters of goaf in 3409 working face are simulated and analyzed. The results show that the porosity value of the upper part of the mined-out area is relatively larger. The porosity of the other regions is relatively lower except the edge of the lower air-blown roadway. Oxidation band width on the air inlet side is 23.2 m, 37.6 m width on the return air side; the high temperature area is mainly concentrated in the return air side and the lower part of the goaf is close to the working face. The oxidation zone is divided by the oxygen concentration combining with the air leakage velocity. The gas concentration in the upper part of the goaf is relatively lower. The gas explosion hazard area is in the area of the middle face support.