ABSTRACT
Coal seam pressure relief and permeability enhancement technology is the key technology for coal mine gas disaster prevention and efficient extraction. The 15249N working face of Jiulong belongs to the outburst risk area of 2# coal seam. By analyzing 2# broken soft coal seam and gas occurrence characteristics, the ultra-high pressure hydraulic slit technology is adopted to carry out the coal seam pressure relief and permeability enhancement test. Two groups of cross-layer boreholes in the mining area of the 15249N working face are selected as comparative test boreholes, and efficient matching technology is adopted on the construction site. The application effect is investigated by comparing the gas drainage concentration and purity of test holes. The field test shows that the single knife coal yield of slotted drilling is 0.98 t, the equivalent slotting radius is 2.04–2.57 m, the average single hole gas drainage concentration of slotted drilling is increased by 1.6 times, and the gas drainage purity is increased by 3.57 times compared with ordinary drilling, and the gas drainage effect of the coal seam is significantly improved.
