Research on Goaf Spontaneous Combustion Early Warning and Three Zone Division Based on Coal Low-temperature Oxidation Mechanism

In order to reveal the oxidation characteristics of residual coal during the stoping period of the 22603 fully mechanized caving face in Changchunxing Coal Industry, the low-temperature oxidation process of the original residual coal is studied through temperature-programmed experiments, and the change laws of oxygen concentration and indicator gases (CO, C₂H₄, C₃H₆, etc.) are analyzed. The experiments show that CO gas is a key indicator for predicting coal spontaneous combustion (critical temperature 49 ℃), while olefin gases C₂H₄ (143 ℃) and C₃H₆ (171 ℃) respectively indicate accelerated oxidation and intense oxidation stages; There are significant defects when CO is used alone as a predictive indicator, in the pyrolysis stage (70-200 ℃), it needs to be combined with the ratio of C₂H₄/C₂H₆ for judgment. Based on the on-site oxygen content observation, divide the "three zone" of the goaf and determine that there is no risk of spontaneous combustion when the advancing speed of the working face is greater than 0.98 m/d.