Study on Gas Control Technology in Slicing Mining of Thick Coal Seam Based on Different-source Prediction Method

Aiming at the problems of the complicated occurrence conditions of the coal seam, the high gas content and emission and the serious gas disasters in 2621-1 working face in Baijigou Coal Mine, a "three dimmentional" gas pre-drainage method was applied to reduce the original gas content of the coal seam before mining with the combination of the gas drainage by long boreholes along seam strike, the gas drainage by floor crossing boreholes and the gas draiange by the boreholes along the the seam being mined; and during mining, comprehensive control measures were used for gas draiange from the over gob by the high-location boreholes, the crossheadings, the plug-in pipes at the upper corner angle and the large-diameter crossing boreholes. After the above measures were taken, the gas content of the coal seam was greatly reduced, the maximum absolute gas emission was 79.76 m³/min in the working face during mining, the maximum gas concentration in return air was 0.51%, and the maximum gas concentration at the upper corner angle was 0.68% during mining, this thus ensured the safe mining of the working face.