Different Prevention Effects of Ventilation Dilution on Methane Accumulation at High Temperature Zone in Coal Mine Goafs

In coal mine goafs, spontaneous combustion of coal can result in methane accumulation, which raises the danger of methane explosion disasters. As an atmospheric control tool, ventilation is applied to ensure air quality for avoiding disasters in underground mines. However, during the process of the spontaneous combustion of coal in coal mine goafs, the impact of ventilation dilution on the possible methane explosions induced by coal combustion has not been well investigated. In this study, a validated gas flow model for the spontaneous coal combustion environment in goafs of coal mines is adopted to investigate the influence of ventilation dilution at the three stages of the spontaneous combustion of coal. The research conclusions suggest that (1) ventilation dilution is a quick measure to dilute methane concentration and intensify heat transfer in the vertical direction in coal mine goafs; (2) ventilation dilution can lessen the danger of methane explosions by diluting methane concentration to the lower explosive limit for methane when coal combustion takes place on the air-inlet side; (3) however, ventilation dilution increases the methane explosion risk by decreasing methane concentration, resulting in explosive methane limits, if coal combustion occurs on the air-return side. This provides a reference for the management of ventilation during a spontaneous coal combustion disaster in the goafs of coal mines with methane.

Automated summary

Spontaneous combustion of coal in coal mine goafs can lead to methane accumulation, increasing the risk of methane explosion disasters. This study investigates the impact of ventilation dilution on possible methane explosions during the spontaneous combustion of coal using a validated gas flow model. The research findings suggest that ventilation dilution can effectively dilute methane concentration and reduce the risk of methane explosions when coal combustion occurs on the air-inlet side, but it can increase the explosion risk if coal combustion takes place on the air-return side. This provides important insights for managing ventilation during spontaneous coal combustion disasters in coal mine goafs with methane.