Prevention Technology of Residual Coal Spontaneous Combustion in Goaf Under the Condition of Large Diameter Borehole Extraction

Based on the background of the large diameter borehole extraction for the goaf of No.2201 working face in Xiaohuigou Coal Mine, the prevention of residual coal spontaneous combustion in the goaf under the condition of the large diameter borehole extraction is studied by using the combination method of theoretical analysis and field test, the dividing method of spontaneous combustion “three zone” in the goaf is proposed through the gas sampling of large diameter borehole. Based on the research results, the prevention and control measures of coal spontaneous combustion in the goaf under the condition of large diameter borehole extraction are put forward. The minimum safe advance speed of working face is 0.46 m/d, the negative pressure of large diameter borehole extraction is less than 8 kPa, the large diameter borehole extraction flow is less than 10% of the air distribution of working face. The grouting materials and the spraying chemical inhibitors are used to prevent the fire, and the large diameter borehole can be used as the fire preventing hole of “one hole with multiple uses”.