Abstract：Based on characteristics of fully mechanized coal mining mechanization and sources of gas emission,using gas monitoring system,arranging on the working surface,through the monitoring of gas volume fraction of coal face,the distribution law of gas volume fraction in coal mining face was studied. Through the collation and analysis of monitoring data,the results show that the gas concentration gradually increases,and between the central to the return air side of mining face the change trend of gas concentration is urgent,especially in close proximity to the return air side at thirty frame of hydraulic support because of the influence of wind velocity air volume and air leakage along the strike direction in the working face; along the dip direction of working face,the gas concentration is higher,high,low,high,and higher,at the same time,the distance between the coal wall to the mined-out area,gas has a minimum value,the lowest point positions are different in different position of mining face.

Keyword：gas concentration;upper corner;gas emission source;fully mechanized coal face;