High efficiency extraction technology and application of bedding directional long borehole along in Coal Roadway

Abstract

In view of the occurrence conditions of coal seam groups in most mining areas in China, the protective layer mining mode is mainly adopted to carry out gas treatment in regional coal seam. In this paper, based on the pressure relief mining of the protective layer, the principle, type and geological conditions of the co-mining mode of the protective layer coal and gas under the condition of coal seam group are analyzed. In Taoyuan Coal Mine, there are some problems such as frequent handling, low efficiency, difficult to control the drilling track, poor drainage effect, etc. The directional long drilling hole is used instead of bottom drainage roadway to reduce the moving time of drilling rig. According to the coal seam characteristics of Taoyuan Coal Mine, the directional drilling rig and other equipment suitable for Taoyuan Coal Mine are selected, and the directional long drilling technology is studied, A total of 13 directional long boreholes have been constructed in the inner section of II 8223 machine roadway, with a total length of 2336m, a lower screen pipe of 2249m, a cumulative coal slag discharge of 480.17t, and an equivalent diameter of 442mm. By January 14, 2020, 78577m3 has been pumped by directional long boreholes, with an average pumping concentration of 15% ~ 100%, and an average net pumping volume of 0.05m3/min ~ 0.40m3/min. It saves the construction of floor drainage roadway, reduces the amount of drilling work for gas control, saves 6 million yuan of gas control investment in the inner section of II 8223 machine roadway, shortens the time for reaching the standard of drainage for 2 ~ 3 months, effectively alleviates the tension of mine production replacement, and realizes safe, economic and efficient mining.