Application on Enhanced Permeability Improvement Technology of Slotting Cross Boreholes Combined with Conventional Cross Boreholes in Coal Drift

According to a poor permeability improvement effect and pressure releasing insufficient problems of the shield coal drift driving with conventional cross b orehole strip layout, the enhanced permeability improvement technology of slotting cross boreholes combined with conventional cross boreholes was provided. The pap er studied the permeability improvement mechanism and site application of the technology was conducted. The study results showed the pressure releasing zone of the slotting cross borehole and the conventional cross borehole could be mutually connected to have integrated pressure releasing, and it could obviously reduce the seam stress in the control region and the enhanced permeability improvement effect would be more obvious. The site trial results showed after the technical measures applie d, the average pure gas flow of the gas drainage increased by 3. 42 times, the initial velocity of the gas emission reduced by 27.0%, the drilling cuttings quantity reduc ed by 3.2%, there was no overlimit phenomenon occurred and the target to eliminate the outburst was reached.