High Efficient Gas Drainage Technology with Fast Full Length Screen Pipe for Borehole Protection in Soft Seam

According to the status of a low borehole gas drainage concentration in a soft seam, small drainage quantity and borehole easycollapsed and jammed, a high efficient gas drainage technology with fast full length screen pipe for the borehole protection in the soft seam was provided and the related key equipment was intr oduced. The application in a typical mine site of Huainan Mining Area showed that with the application of the technology, 75% of the borehole could be realized and co mpleted within one hour, all boreholes could be completed with two hours and 85% of the borehole screen pipe could be set to 81% of the borehole depth. A gas draina ge volume fraction of a single borehole could be increased from 30% to 60% and the pure gas drainage volume could be increased from 0.03 m3/ min to 0.06 m3/ min. The unit gas drainage volume fraction was increased about 120% and pure gas drainage quantity was increased from 2.0 m3/ min to 4. 2 m3/min. The application of th e technology could eliminate borehole failure caused by borehole collapsed, could highly improve the reliability of borehole gas pre- drainage and could ensure the gas pre- drainage effect of coal mining face.