Goaf Gas Flow Law and Application of Gas Drainage Technology with Separated Gas Resources

In order to reduce the gas emission from the goaf of the coal mining face and the gas content at the upper corner of the coal mining face,a theoretical analysis was conducted on the roof crack variation and the gas flow law of the goaf.Based on the circumstance,a comprehensive gas drainage control method with the separated gas resources,including the gas drainage with the buried pipeline at the upper corner and the gas drainage with boreholes drilled at the high level drilling site for the roof cracks was provided for the gas drainage of No.21141 coal mining face in Zhujiao Mine.The application results showed that the application of the drainage technology with separated gas resources could make the gas volume fraction at the upper corner of No.21141 coal mining face reduced from the previous 0.6% to 0.4%.The gas drainage volume fraction of a single borehole at the high level drilling site was 34% in average and the gas flow was 0.062 m3/min.Thus the gas emission from the goaf was reduced and the safety production of the coal mining face could be ensured.