Fire Prevention and Control Technology with Sealing and Liquid Nitrogen Injection During Withdrawing Period of Coal Mining Face

According to the coal spontaneous combustion in goaf during No.Y252 coal mining face withdrawing from No.2 seam, a sealing and liquid nitrogen injecti on method of the coal mining face was applied to study on the fire prevention and control during the withdrawing period of No.Y252 coal mining face in Yangchangwan Mine.The results showed that after sealing and liquid nitrogen injection the CO volume fraction reduced from 0.008% to 0.002%, the ethylene volume fraction reduced fr om 0.002% to 0 and the temperature reduced from 29。C before the liquid nitrogen injected to 25 °C.With the liquid nitrogen injection in the goaf to rapidly eliminate the high temperature points in the goaf, the oxidation of coal left in the goaf could be effectively restrained and the fire extinguishing role effect was remarkable.