Optimization and application of coal spontaneous combustion index gas in Xutuan Coal Mine

In order to effectively prevent the spontaneous combustion of residual coal in 3₂38 working face of Xutuan Coal Mine, the coal spontaneous combustion tendency test and low temperature oxidation test analysis are carried out by collecting the coal samples from the working face, the index gas for predicting coal spontaneous combustion is optimized; when the coal temperature is between 20 ℃ and 100 ℃, CO is used as the indicator gas; when the coal temperature is between 100 ℃ and 150 ℃, C₂H₆ is used as the indicator gas; when the coal temperature is above 150 ℃, C₃H₈ is used as the indicator gas, and the chain to alkane ratio is used as the auxiliary indicator parameter. According to the test results, the function formula between the gas volume fraction and temperature is obtained by interpolation fitting method. Based on the established fitting function, the volume fractions of CO, C₂H₆ and C₃H₈ can be calculated by detecting the temperature of coal, which can be used to predict the spontaneous combustion status of goaf. The result of field application shows that the prediction effect of residual coal spontaneous combustion in goaf is good.