Research on safe advancing speed of spontaneous combustion isolated working face

The risk of rock burst is a natural property of isolated working face. The anti-shock decompression will affect normal advancing speed of isolated working face and increase risk of spontaneous combustion of coal seam.Therefore, when determining safe advancing speed of isolated working face, the requirement of anti-impact must be considered.In view of problem that rock burst risk is seldom considered in determination of safe advancing speed of isolated working face, 93down05 working face in Jining No.2 Coal Mine was taken as a research object to analyze oxygen-poor characteristics in upper and lower adjacent goaf at stopping line and distribution law of dangerous area of the goaf in working face, the following conclusions were obtained: when O2 volume fraction is 6%, the time for the coal sample to oxidize from initial condition to critical temperature is 253 d，and the working face mining should be completed within 253 d; considering fire prevention requirements, the minimum advancing speed of the working face is 3.7 m/d; considering rock burst prevention requirements, optimized safe advancing speed ranges of unprotected area and protected area are 3.7-5 m/d and 5.04-8 m/d, respectively. The advancing speed not only guarantees coal spontaneous combustion safety on three sides of goaf during mining of 93down05 working face, but also does not bring new rock burst risk to the working face, and ensures safe mining in the production cycle of the working face.