| Mine gas and leaf coal spontaneous combustion disaster seriously restricts the safe and efficient mining of fully mechanized top coal caving mining face.The high pumping method is one of the effective technical means to control the gas in the goaf.However,the high pumping gas drainage will change the distribution of air leakage in the goaf,and then accelerate the spontaneous combustion of coal.Therefore,the paper studies the influence of negative pressure pumping on the gas migration and the spontaneous combustion of the coal in the goaf,determines the equilibrium point of the spontaneous combustion control of the coal and the coal in the goaf.Prevention is particularly important.In this paper,the geological conditions,the distribution of gas source and concentration,the causes of gas(natural factors and mining conditions)of the mining face in Yangquan No.3 Mine are analyzed.Dimensional calculation model,the parameters of porosity development and porosity were preliminarily determined.The influence of negative pressure extraction on the spontaneous combustion of coal in goaf was analyzed,and the gas concentration of goaf under high pumping distance was established Dimensional model;the gas migration model of goaf area was constructed by COSMOL software.The effect of air leakage on the gas migration in goaf was studied under different conditions of high spatial pumping and low height pumping The distribution characteristics of the "three zones" are studied,and the pumping position range of high pumping and low altitude is given.Through the monitoring of the gas concentration in the goaf and the change of the gas concentration in the goaf,the variation law of the spontaneous combustion "three zones" and the gas concentration in the goaf was obtained,the effect of gas extraction and coal spontaneous combustion control was carried out.The results show that the reasonable layout of reasonable high-level mining can meet the safe mining of fully mechanized top-coal caving face. |
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