Study on hazard zone of coal spontaneous combustion in adjacent goaf along working face

To explore the hazard zone of coal spontaneous combustion in the adiacent goaf at different stages of the roadway driving face, the 2202 working face and the 2201 adjacent goaf of Yingpanhao Coal Mine were taken as examples. The large-scale experiment was conducted to analyze the coal spontaneous combustion limit parameters of the 2201 goaf. The conditions for identifying the hazard zone of coal spontaneous combustion in the adjacent goaf were proposed. Monitoring the gas concentration and temperature in 2201 adjcent goaf by the drilling holes through coal pillar, and the numerical simulation was conducted to study the oxygen concentration distribution in 2201 adjcent goaf, and the hazard zone of coal spontaneous combustion in the adjacent goaf was obtained. The results show that during the mining period of the 2202 working face, the coal pillar was broken by the stress concentration, and the oxygen volume fraction of the adjacent goaf was in the range of 10.1% to 13.8%. The oxygen volume fraction of the adjacent goaf before the stop mining period was between 10.3% and 15%. During the mining period, a narrow area on the coal pillar side with width 55 m from the front 45 m and behind 119 m of 2202 working face in the adjacent goaf was the coal spontaneous combustion hazard zone. Before the stop mining period, a narrow area on the coal pillar side with width 42 m from the front 63 m and behind 107 m of 2202 working face in the adjcent goaf was in an oxidizing environment.