Pressure–Relief Gas Cooperative Drainage Technology in a Short-Distance Coal Seam Group

The gas in a coal seam is clean energy source, but it also the main cause of accidents during mining mineral resources. There large pressure–relief influx upper and lower adjacent layers 1211 working face Wanfeng Coal Mine Jinhui, Shanxi Province, China. Based on evolution law overburden fractures, collaborative extraction mode “directional drilling gas-conducting fractured zone + staggered buried-pipe goaf” innovatively proposed. research results indicate that, under influence pressure gradient buoyancy, gas–concentration enrichment formed at distance 10.8–24.1 m from boundary layer. After optimizing arrangement roof directional-drilling layer position, as well buried pipe drainage, average gas-drainage rate reached 83.2% test face, volume fraction corner was maintained below 0.7%. This can greatly improve efficiency resources utilization short-distance groups, while solving problem accumulation caused by negative air flow process