Research and application of collaborative gas extraction technology for protective layer mining and pressure relief

In response to the problem of collaborative extraction of gas from the pressure relief of the overlying protected layer and the lower protective layer after the mining of the protective layer under the deep low-permeability and outburst coal seam group, Xinjing Mine has adopted "surface well pre-extraction+high (low) level extraction roadway" to achieve collaborative extraction of gas from the pressure relief of the protected layer and the upper corner gas. The composite utilization of antireflection measures such as mechanical drilling and surface well fracturing has improved the extraction efficiency of the No.15 coal seam in Xinjing Mine. The net gas flow extracted from the gas branch pipe is increased by 2.27 times after anti-reflection, shortening the standard time for pre-extraction of gas from the protective layer working face. The net gas flow of the pressure relief surface well of the protected layers of No.3, No.8 and No.9 after the mining of No.15 coal seam is increased by 1.85 times, and the collaborative gas extraction of the protected layer and the protective layer is realized. It is of great reference significance for safe and efficient mining of coal seam groups in Yangquan mining area to achieve safe and controllable mining of outburst coal seam groups.