LAUSR

Closing the fire area is a common disaster-relief measure when coal spontaneously combusts in a goaf. However, the closure process will also increase the risk of gas explosion. To understand the gas migration rules and disaster-causing effects in a closed goaf, this study simulates the spontaneous combustion of leftover coal when the goaf is closed. The simulation was visualized on the PyroSim interface. After identifying the distribution laws of the temperature field, CO concentration field, and O2 concentration field, a disaster risk analysis was carried out The CO concentration presented two different changing trends over time. Both trends were approximately linear. A potential high-temperature fire source was identified at depths of 50–60 m in the goaf (approximately 3 m above the floor). Before the goaf closure was completed, likely gas-explosion sites were found at depths of 30, 50, and 80 m from the working face. Monitoring the gas and oxygen concentrations is especially important in these areas.