Comprehensive Fire Preventing and Extinguishing Technique of Gob-side Entry Retaining Face

After finishing the upper district sublevel face, the district sublevel haulage entry was retained as the lower upper district face tailgate entry by the effective support methods. All above measures were named gob-side entry retaining technique which has the merits of effective control of gas exceeding limits, rational exploitation of coal resources, improving the coal recovery rate and reducing the amount of roadway driving. The gob-side entry retaining was formed using the flexible formwork and pump-concreted support technique. The flexible formwork wall can cause larger air leakage because roof contact was unclosed, or the local area was fractured. Additionally, the coal seam has a higher spontaneous combustion tendency; the more residual coal in gob might appear spontaneous combustion. In this case, the comprehensive fire preventing and extinguishing technique measures including nitrogen injection, grouting and enhancement of monitoring were introduced on Shangwan Coal Mine gob-side entry retaining technique. Finally, the spontaneous combustion accident was completely eradicated successfully. The face was finished safely.