Study on Relief Effect of Upper Protective Coal Seam Mining at Long Distance in Deep Mine

Based on the characteristics of swelling deformation of coal seam under the mining of protective layer, the lower protected layer stress change and expansion deformation were analyzed by using FLAC^3D5.0 under the conditions of remote distance protective coal seam of Zhujixi Mine. And the protected layer gas flow was examined. The results showed that after the protective layer mining, the maximum expansion rate of the protected layer reached 2.2‰ after mining, and within the range of 40 m to 80 m in the working face of the protective layer, the gas extraction flow of the single hole of the protected layer increased from 0.05 m³/min to 0.35 m³/min. The gas permeability of the coal seam increases significantly, which has a certain pressure relief effect on the coal seam of the protected layer. The combination of borehole pressure relief gas in the pressure relief impact zone can reduce or eliminate the outburst risk of the protected layer.