Research on spontaneous combustion"three zones"and the critical values of indicator gases in the 31110 working face of the Cuncaota NO.2 Coal Mine
Basing upon the theory of coal spontaneous combustion in goaf,the distribution range of the"three zones"of spontaneous combustion was studied through on-site observation,numerical simulation and other methods,and the safe advancement speed of the working face was calculated.Basing upon experimental data of gas products generated by coal sample program heating,the natural ignition marker gas of coal seam 31 was the best selection,and the critical value of spontaneous combustion in the 31110 fully mechanized mining face of Cuncaota NO.2 Coal Mine of China Energy Shendong Coal Group Co.,Ltd.was calculated and analyzed.The research results show that the"three zones"distribution of spontaneous combustion approximately presents an"L"shape in the goaf of the 31110 working face,the width of the oxidation zone(214 m)on the side of the main transport roadway supported by the flexible formwork wall is significantly larger than that on the side of the auxiliary transport roadway in the goaf(79 m),the safe advance speed of the 31110 working face is 4.76 m/d,and the normal daily average advance speed is 11.88 m/d,which meets the requirements of safe mining.CO,C2 H4,and C2 H2 were selected as significant gases to measure the different stages of spontaneous combustion in the 31110 goaf,the critical concentration of CO in the upper corner of the goaf is 41.54 × 10-4％,and the critical concentration of CO in the return airway is 4.15 × 10-4％.A management system for fire classification warning response and fire prevention and control technology for 31110 working face was established,which providing a basis for early prediction and prevention of coal spontaneous combustion fires in the 31110 working face.
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