Abstract: In this paper, based on the gas extraction technique of upper roadway in high gas and easily spontaneous combustion coal seam, taking the study of spontaneous combustion mechanism as point of penetration, according to the actual spontaneous combustion situation of LW13190 in Gengcun coal mine, Yima coal industry group, we have studied the strata fracture development, air leakage passage model, expansion property of float coal in goaf, and power source of air leakage, et al, by using theoretical analysis, mathematical model and field aided test. The results show that the gas extraction in upper roadway has increased the spontaneous combustion risk in the high gas and easily spontaneous combustion coal seam, ,which mainly embodies in: 1) Air leakage passage and power are exist in the port between the coal face, goaf and upper drainage roadway; 2) The coal- rock mass fractures are fully development duo to mining stress and loose circle of drainage roadway, while the compaction degree of float coal in goaf decreases, and the expansion property of float coal increases, which are beneficial to the spontaneous combustion and heat storing of coal mass; 3) Once the float coal in goaf is oxidized, the temperature gradient will exit between the high temperature dot in goaf and air leakage passage. Then, the formed endogenous fire pressure will exacerbate the spontaneous process of broken float coal in goaf, and induce the spontaneous combustion of float coal.

Key words: gas extraction, spontaneous combustion, fracture, air leakage, heat storing, endogenous fire pressure