Research of inorganic fire‐extinguishing materials on preventing and controlling gas and coal spontaneous combustion in the narrow coal pillar and adjacent goaf

Summary To reduce the pressure on underlying coal seam and maximize the mining efficiency of coal resource, narrow coal pillar mining technology is often used. However, for coal mines with high gas and spontaneous combustion, this technology can cause gas and coal spontaneous combustion composite disaster easily. In this paper, we adopted a new type of inorganic fire‐extinguishing material (IFEM) to prevent and control gas and coal spontaneous combustion composite disaster. The result shows that the destruction of narrow pillar caused by stress extrusion and mining disturbance is the internal cause of gas and coal spontaneous combustion composite disaster. IFEM can go deep into the cracks of coal mass to seal up the cracks and reduce gas exchange between roadway and adjacent goaf. Meanwhile, it is full of moisture in the interior, which can reduce the temperature of coal mass through evaporation and heat absorption. The IFEM has the characteristics of high water retention, strong fluidity, and strong flame retardant, which can inhibit the generation of free radicals in coal mass at both physical and chemical levels, prevent the spontaneous combustion of coal mass, and reduce the occurrence of composite disasters of gas and coal spontaneous combustion. Highlights The crack inside the narrow coal pillar develops, and the gas permeability is good. The combined disaster in the narrow coal pillar working face is serious. IFEM can seal cracks and increase the strength of narrow coal pillars. IFEM can inhibit the generation of free radicals in coal and prevent coal from contact with oxygen.