Seam Permeability Improvement Technology and Application with Hydraulic Guided Drilling Through . Strata and Borehole Blowing

According to the coal and gas outburst mechanism, based on the analysis on the drilling through seam and borehole blowing in the low permeability and outburst seam to improve the gas drainage mechanism, an optimized design was conducted on the introduction blowing technique and gas drainage borehole layout in t he seam drilling through strata.A site experiment was conducted on the coal mining face in No.7 seam of Qinan Mine of Huaibei Coal Mining Group.The experiment res ults showed that the hydraulic guided drilling through strata and blowing in seam could make the permeability of the seam within the borehole group improved by 150 ti mes.The average gas drainage rate of a single borehole was improved by over four times.The outburst danger seam for fully mechanized roadway heading was eliminat ed.The average heading rate was reached at 200 m/month and was 45 times higher than the driling and blasting heading with the conventional gas control method.