Dangerous Area Determination of Coal Spontaneous Combustion in Goaf Under the Condion of Gas Drainage

Gas drainage will not only increase air leakage in the goaf, cause the migration of “three zones”, increase the risk of spontaneous combustion of coal in goaf, but also cause the disorder of goaf and accumulation of gas, which makes the danger area of coal spontaneous combustion in goaf more complicated. Aiming at the actual situation of high gas occurrence in 4204 working face of Jianbei Mine, through on-site observation, the distribution of floating coal thickness, oxygen concentration and air leakage strength in goaf are obtained. Combined with the characteristic parameters of coal spontaneous combustion, we analyzed the risk of goaf, divided the goaf “three zones” under the condition of extraction and determined the goaf spontaneous combustion danger area and safe advance speed of preventing of spontaneous combustion in goaf.