Study on occurrence characteristics of coal seam gas and its key geological factors

Geological structure has obvious control effect on gas hazard.Taking Tunlan coal mine of xishan coalfield as the research object,this paper analyzed the influence of geological factors such as buried depth of coal seam,surrounding rock condition,hydrogeology,coal metamorphism degree and geological structure on gas occurrence,and found that fault was the key factor of gas occurrence.According to the distribution characteristics of faults,Tunlan coal mine is divided into four relatively independent geological units.Based on the measured data,the effects of fault distribution and combination methods and local small faults on the occurrence of gas in the local units were analyzed.The data of gas emission from the working face of Gaolan Coal Mine were verified.The results show thatthe gas occurrence in Tunlan coal mine was mainly controlled by NE direction fault and buried depth.Regional structure has a prominent influence on gas occurrence.The combination of faults makes local gas content abnormal.The amount of gas emission in workplace is closely related to geological structure.Gas emission significantly increased near large faults and local small faults;the division of geological units was of great significance to coal and gas outburst mines with complex geological structures.