Research on safe advancing speed of spontaneous combustion isolated working face
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摘要: 冲击地压危险性是孤岛工作面的一种自然属性,防冲减压会影响孤岛工作面正常推进速度,加大煤层自燃危险性,因而确定孤岛工作面安全推进速度时,必须要考虑防冲要求。针对以往孤岛工作面安全推进速度的确定较少考虑冲击地压危险性的问题,以济宁二号煤矿93下05工作面为研究对象,分析了终采线处上下邻近采空区的贫氧特性和工作面采空区的危险性区域分布规律,得出以下结论:当O2 体积分数为6%时,煤样由初始条件氧化至达到临界温度的时间为253 d,应保证工作面在253 d内回采完毕;考虑防火要求,安全推进速度应不小于为3.7 m/d;考虑防冲要求,优化后未保护区和保护区的安全推进速度范围分别为3.7~5 m/d和5.04~8 m/d。该推进速度不仅保证了93下05工作面回采期间三面采空区的煤自燃安全,而且不会给工作面带来新的冲击地压危险,确保了工作面生产周期内的安全回采。Abstract: 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.
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