Coal spontaneous combustion prevention technology in mining face of gateway driving along goaf during mining stop period

In order to effectively prevent and control coal spontaneous combustion occurred during the mining period of the gateway drivingalong goaf,the spontaneou s combustion index gas and critical value of No.32 seam were tested and analyzed in the lab. The UDEC softwarewas applied to analyze the stability of the small coal pilla r left by the gateway driving along the goaf. The max vertical stress on the coal pil-lar was 12 MPa,the max displacement value in the vertical direction and horizontal direct ion was 2.076 and 0.547 1 m individually. TheFluent software was applied to analyze the easy spontaneous combustion area with less stressed coal pillars and at a directi on toward thegoaf 25 ~ 75 m of the small pillar was a spontaneous combustion oxidized zone scope. According to the analysis results,coal spontaneouscombustion prevent ion and control measures integrated with the ventilation air volume reduction,optimization of the index gas monitoringand measuring points and quantitative safety early wa rning critical value,three phase foam pipe buried in the goaf and small pllar sponta-neous combustion area were conducted. During the half year production stop period,CO volume fraction behind the powered support at theupper corner was stabilized at about 20x 10-6,02 volume fraction was kept at 18%,and a good spontaneous combustion prevention andcontrol effect was obtained.