Fire Prevention and ExtinguishingTechnology for Mining of Contiguous Inflammable Coal Seams Group

In order to prevent coal spontaneous combustion in the mining of the contiguous coal seams group, a comprehensive regional pressure balancing ventilation system was constructed in K₁₂ an K₁₄ working faces in Yanjing No.1 Mine. The spontaneous combustion of coal seams was controlled by taking the measures such as the control of air leakage in the gob, the dynamic regulation of the pressure difference and the nitrogen injection into the gob, and their control effect was analized. The results showed that the gob temperature reduced from 26 ℃ to 24 ℃, the oxygen concentration reduced from 20% to 11%，the carban monoxide concebtration decreased from 110×10^-6 to less than 50×10^-6 , the carban dioxide concentration was about 0.5%, and the sensitive indexes of spontaneous combustion of coal seams decreased obviously, so the purpose of preventing coal spontaneous combustion in the gob was achieved.