Abstract: The gas control technical measures about gas emission by wind,bedding drilling and downward drilling of roof are obtained in Hudi Coal Mine.With the increasing of the production scale of Hudi Coal Mine,the above gas extraction technical measures can not guarantee the gas concentration of working face within the safety scope of indicators.Taking the working face of 3# coal seam in Hudi Coal Mine as the study example,the technical scheme for gas extraction of the working face in low permeability coal seam in high outburst pit is studied.According to the scheme,the gas can be extracted effectively by adding coal seam floor rock roadway and setting roof penetrating drills in the rock roadway,besides that,combing with the ground coalbed gas wells and the scheme proposed in this paper to extract the gas in the area without any mining or stripping activities.The practice results of the scheme proposed in this paper show that the gas extraction quantity is increased from 6.6 m3/min to14.48 m3/min,the gas gas extractive rate is increased from 18% to 40.5%,the gas extraction effective of the working face can meet the requirements of gas extraction,the gas overrun problem of the working face is solved,and the safety and efficient production of the working face is guaranteed.

Key words: Gas extraction, High outburst pit, Low permeability coal seam, Roof penetrating drill, Coalbed gas well