Dynamic Dragging Pipe Gas Extraction Technology for Goaf in Closed Distance Coal Seam Group

This paper analyzes the problem of gas over-limit in the return air corner of 3338 working face of Zijiang Coal Mine, it is inferred that the main reason for the over-limit is the gas flowing to the mining face in the adjacent layer by communicating the cracks. In this paper, the dynamic dragging pipe extraction technology in goaf is proposed. A 12 m long large-diameter drainage pipe is arranged in the wind lane to the goaf, and the outlet pipe port is kept at the position of 7 m to 9 m in the goaf, in addition, a drainage branch pipe is drawn out to discharge the gas at return air corner. This method not only intercepts the high concentration gas in the goaf, but also effectively exhausts the eddy gas in the return air corner.