Simulation Analysis of Goaf Gas Extraction for the First Working Face in Outburst Danger Coal Seam

By analyzing the geologic features of 10414 working face in outburst danger coal seam, and referring to the changing laws of strata fractures and gas flow patterns, and based on the CFD model, gas distribution in goaf, buried pipe drainage, and drainage effect by the use of both buried pipe and high level borehole were simulated, and the engineering verification at 10414 working face was conducted. The results show that gas mainly gathers in one side of return airway and it provides evidence for judging the efficient range of goaf gas drainage. Gas concentration falls to 0.5% at upper corner when buried pipe and high level borehole are mined simultaneously; and there is no phenomenon of gas over limit at working face; during the field practice, gas can be extracted 40% with joint drainage and the gas volume reaches 12.5 m³/min, which indicates that it provides good practical effect for the application of goaf gas drainage theory on the first working face in outburst danger coal seam.