| coalbed gas Discharge is very important for mining safely, borehole and laneway play a leading role of coalbed gas discharging in China. Drilling borehole in hard coal seam is mostly used to discharge gas,and cross layer borehole, roof rock borehole and laneway are mainly used to discharge gas in soft coal seam. The effect of gas discharging is limited by length ,diameter of borehole in coal seam and high cost of laneway development.Aimed at aboved-mentioned key problems, The research of this paper mainly focus on following aspects: firstly, designed strongly deflecting assembled drilling rigs and tested its function in Yangquan mining area, accomplished six large diameter bent boreholes with more than 1.2°/m the deflecting intensity, increase the length of borehole in crack zone from 10m to 16m with 153mm terminal diameter. secondly, calculated, analyzed and tested three kinds of the stabilized assembled drilling rigs in Jincheng and Tongchuan mining area, accomplished the longest borehole in coal seam in China, and the length of borehole is up to 865m with 153mm terminal diameter, the effect of gas discharging with new drilling rigs is significantly improved than that with traditional drilling rigs. Thirdly, compiled program by Visual Basic for processing measured data and outputting trail of borehole. The outputed trail is accord with measured trail, and can be used to guide drilling directional borehole.The conclusions of research show that drilling borehole can greatly improved the effect of gas discharging by the horizontal directional drilling technology and the strongly deflecting drilling technology, some discharging parameters show that the effect of discharging is better with large diameter bent borehole than that of with traditional borehole and the laneway. The program can be use to effectively process measured data of borehole and output trail of borehole.
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