Gas outburst disasters and the mining technology of key protective seam in coal seam group in the Huainan coalfield

Coal and gas outburst disasters in coal seams are becoming more serious as coal mines extend deeper underground in China. To aid gas control in high-gas outburst coal seam group, this study performed research based on the geological conditions of the Xinzhuangzi coal mine in the Huainan coalfield. The laws of gas occurrence, the strength of the coal outburst, and the regional partition were studied. Simultaneously, we introduced the key protective seam mining technology and confirmed the mining sequence of coal seam groups. The results indicate that (1) each seam absorbs gas well, and the currently measured gas content is up to 15.0 m<Superscript>3</Superscript>/t. (2) Although some differences about coal seams outburst intensity remain, the differences in the same group are very small. (3) The coal seam B10 was chosen as the key protective seam and was mined first; then adjacent seams were mined from bottom to top by layer within the roof of B10 and from top-to-bottom within the floor of B10 to guarantee each adjacent coal seam received the good effects of pressure-relief and increasing permeability. (4) The main methods of gas extraction in each protected seam are surface boreholes and net-like penetrating boreholes in the floor roadway, and related technical parameters were determined according to the degree of pressure-relief in coal seam. This in situ experiment indicates a method aiding the gas control problem and guaranteeing safe and highly efficient exploitation of high-gas outburst seams. Copyright Springer Science+Business Media Dordrecht 2013