Investigation on the Reasons for CO Overrun in the Return Air Corner of the Fully Mechanized Coal Mine Working Face

Abnormal CO gas concentration is one of the common problems in coal mine safety production. In view of the phenomenon of CO overrun in the working face, this paper takes the fully mechanized discharge working face of Zhaoxian Mine as the research object, analyzes the occurrence of primary coal seam gas through the coal sample tank analysis experiment and the indoor crushing experiment, and explores the source of CO in the fully mechanized working face. According to the calculation model, the predicted value of CO concentration at the return air corner of the working face was calculated and, combined with the gas data of the working face monitored on site, it was proven that the CO concentration of the working face was in the normal range. This study found that the oxidation of residual coal in the goaf and the generation of CO during the mining process were the main reasons for the high CO concentration in the working face, rather than the occurrence of raw coal. This study reduces the interference of CO concentration on the determination of coal spontaneous combustion, prevents the misjudgment of coal spontaneous combustion, ensures the safe production of the Zhaoxian Coal Mine, provides data and theoretical support for the subsequent establishment of the CO prevention and control system of the working face, and provides a solution and technical reference for the CO overrun phenomenon in the working face of other high-gas mines.