Study on multi-source analysis and prevention of CO in return corner of composite goaf

The source of CO in the return corner of the composite goaf is more complex than that of a single coal seam, and the CO overrun seriously affects the health and safety of miners and the accurate prediction of coal spontaneous combustion (CSC) in the goaf. In this paper, through SF 6 tracer technology, beam tube thermocouple monitoring in goaf and CO test in multi-period working face, the different sources of CO in the return corner of composite goaf during coal mining and maintenance are comprehensively determined. Based on this, a real-time online monitoring system for coal cyclic oxidation at ambient temperature was independently designed to study the gas production law of residual coal with different mixing ratios, and the gas production law of coal crushing during coal mining was mastered through the coal crushing experimental platform. The oxygen isotope test was carried out on different ways of producing CO in the composite goaf, and the proportion of each source during CO mining and maintenance in the return corner of the composite goaf and the proportion of residual coal in the overlying goaf were determined. According to the importance of each source, the comprehensive prevention and control technology for CO overrun in the return corner of the composite goaf was proposed. Through this system method, the problem of CO overrun in the return corner of the composite goaf is effectively controlled, and the occurrence of coal spontaneous combustion disaster in the goaf is inhibited.