Disaster occurred mechanism and prevention of coal spontaneous combustion in goaf of seam under magmatic rock bed

Aiming at the status of spontaneous combustion of high gas coal seam under the magma rock bed of Yangliu Coal Mine in Huaibei Mining Area, the mechanism of spontaneous combustion of coal in goaf is studied by means of experimental tests and numerical simulation. The results showed that the thermal metamorphism of magma intrusion increased the degree of metamorphism of the coal seam, reduced the ability of the coal seam to absorb oxygen by 1.09%, and reduced the tendency of spontaneous combustion. During the mining period, the rock bed plays a key stratum, resulting in the separation fissure development of the rock mass under the rock bed. The degree of compaction in the goaf was reduced, the maximum porosity was about 1.55 times that of no bed cover, and the maximum permeability was about 6.88 times. The larger porosity and permeability made the goaf increase,and the oxidized zone was expanding. On this basis, a comprehensive fire prevention technical scheme suitable for the geological conditions was constructed, which effectively prevented the spontaneous combustion of the residual coal in the goaf of Yangliu Coal Mine.