Study on distribution of "Three Zones" in goaf of fully mechanized underhand mining face

In order to prevent against spontaneous combustion of coal in goaf,thermocouple temperature measurement system and bundle pipe gas monitoring system were applied to observe 1021 fully mechanized underhand mining face of wugou coal mine,and the change conditions of temperature and oxygen concentration in goal were obtained.Finally the range of three zones of goal was ascertained by analysis of the measured results of temperature and oxygen concentration and optimization of MIN-MAX method.In combination with the period of coal spontaneous combustion in Wugou coal mine,the critical speed of mining face could be calculated to efficiently guide fire prevention work of mining face.