Directional borehole gas management is used in the recovery surface of the high gas mine. Through the analysis of the gas storage in the recovery surface and adjacent layers, as well as the perforation analysis of the directional boreholes in the upper rock layer of the recovery surface, the design of this working face adopted a comprehensive extraction method combining the pre-extraction of the cascading borehole, extraction of the high level directional borehole and the upper corner buried pipe. When the average daily production of raw coal at the recovery surface was 4 500 t, the absolute gas outflow was 12 m3/min, the return flow gas concentration was about 0.25%, the wind discharge gas was 3.8 m3/min, the extraction gas was 8.2 m3/min, the extraction rate was 68%.
