Investigation of High Pressure Water Jet with Hydraulic Reaming Drainage Radius for Coal Seam Mining

Test mine is a large modern mine, the 13-1 coal-seam original permeability coefficient was low, gas pressure and content were higher, coal seam outburst danger of serious, directly extracting coal gas is difficult. Using a new type of high pressure water jet reaming technology, can achieve the expansion of borehole diameter, increase coal seam exposed area and pressure relief range, thereby improving the coal seam permeability, increased coal seam drainage radius. Investigated on the basis of determination of the original coal seam gas pressure and content of the coal extraction radius after the hydraulic reaming. Provide the basis for the seam of the test area borehole design