Study and Practice of Gas Migration and Coal Spontaneous Combustion Law in Gob in Jinjia Coal Mine

In this paper,study was carried out on the law of gas migration and residual coal spontaneous combustion in gob during coal mining to counter the contradictions between the gas drainage from gob and the air leakage reduction for the prevention of coal spontaneous combustion in gob.The gas composition and concentration in the working face were measured with the method of laying monitoring points along the whole face and the law of gas migration and coal spontaneous combustion and the distribution ofthree zonesin the gob were found out by analysis.Based on the field measured data and analysis results,a model was set up and numerical simulation was conducted on the gas distribution and air leakage in the gob with FLUENT software,the variation law of spontaneous combustion zone and gas emission in the state of gradually-changing air supply was obtained and on this basis, the safe air quantity that can simultaneously meet the requirements for preventing disallowed gas concentration and coal spontaneous combustion in the working face was gotten.