Fire Extinguishing Technique for Short Distance Coal Seam Group Extension Zone

In order to eliminate the extremely complex No.4 fire area at +1 030 level caused by improper filling of foam material in 4238 coal mining face, according to the features of the inclined close range coal seam and positive pressure ventilation, the comprehensive fire extinguishing policy of “first closing then reducing and then treating, first cooling and then filling, first core and then peripheral, the aim to isolate the fire area and ensure production succession” was formulated, a series of fire extinguishing measures including long distance sealing and progressive shrinking sealing in positive pressure fire area, filling of new inorganic material roadway and small section recovery, direct injection of mobile liquid carbon dioxide underground, and roadway construction measures under the core fire area were adopted. The results show that the fire was effectively controlled and the staged extinguishing achievement has been achieved, however, the extension trend of the fire area has not been completely reversed, and the state of fire area was still fragile, subsequently, through further taking the measures of fly ash compound colloid grouting, the roadway of the core and the peripheral area of the fire area is filled step by step, the horizontal tunneling, replacement under the cover of isolate fire area and the fire extinguishing work were completely achieved.