Abstract: To solve the problem of gas exceeding limit in upper corner caused by large gas emission in goaf of high gas fully mechanized mining face,the high directional long borehole gas extraction technology was proposed to control gas in goaf.The height of fracture zone in overlying rock strata during mining was calculated by numerical simulation,and reasonable parameters of directional long borehole extraction were designed.The field application results show that the gas extraction technology with high directional long borehole has high concentration,stable flow rate,long effective extraction time,and no gas overrun in upper corner occurs during the mining period.The gas extraction effect is remarkable,which ensures the safe and efficient production of the mine.

Key words: Gas extraction, Fracture zone height, Directional long borehole, Upper corner, Goaf