Optimization of index gases and division method of spontaneous combustion "three zones" in 10 coal seam of Qingdong Coal Mine

In view of problem of natural fire on 1078 working face of Qingdong Coal Mine, through a combination of laboratory research and on—site testing, the main and auxiliary indicators of spontaneous combustion index gases were optimized: CO and C2H4 can be used as main indexes of oxidation and spontaneous combustion of coal in 10 coal seam, olefin ratio and alkane ratio are used as auxiliary indexes of oxidizing spontaneous combustion index gas of coal in 10 coal seam. The spontaneous combustion "three zones" in goaf were divided by two indicators of oxygen concentration variation law and temperature change trend in goaf: the heat dissipation zone is 0～31 m from the working face, the spontaneous combustion zone is 31～78 m from the working face, and the suffocation zone is 78 m far away from the working face. The research results provide scientific basis and theoretical guidance for natural fire control on 1078 working face.