Key technologies for extinguishing coal pillar self-heating in close distance coal seams

The coal pillar self-heating process of the 16# coal seam, which lays above the 18# coal seam that being mined in Dongrong 2# coal mining was examined. The cause of upper pillar spontaneous combustion during the mining of close distance coal seams was analysed. According to the distribution characteristics of the mining areas and the gas detective result, the scope of high temperature was judged, and the main method asphyxia and cooling was determined. This included infusion of polymer colloid and three-phase foam into flame location, a wide range of gob nitrogen injection, and effective plugging measures. The results showed that these measures rapidly extinguished coal pillar self-heating, lowering the CO concentration from 16000 ppm to about 10 ppm and reducing the temperature from 81℃ to less than 20℃ in the closed system of 16# coal seam. Illustrating that though various material of extinguishing applied, the problem of coal pillar self-heating was eliminated efficiently.