Study on Selection Method of Directional Drainage Borehole in Long-Distance Goaf of Near Horizontal Coal Seam
[Purposes]To solve the problem of selecting directional drainage boreholes for long-distance goaf in near horizontal coal seams,a quantitative evaluation method is needed to provide a basis for the construction of mine water exploration and drainage engineering.[Methods]This article constructs a di-rectional drainage drilling water volume calculation model for long-distance goaf in near horizontal coal seams.Based on the Bernoulli equation,it comprehensively analyzes parameters such as hole position,aperture,and depth,and derives formulas for calculating the water inflow of single and branch holes.[Findings]Taking the directional drainage drilling in the goaf of the Mudu Chaideng coal mine as an ex-ample,the accuracy of the calculation formulas was analyzed and compared.At the same time,the water volume and economic benefits of single hole and branch hole under near horizontal coal seam conditions were compared and analyzed.[Conclusions]The influencing factors and selection methods of directional drainage drilling layout in the near horizontal coal seam long-distance goaf have been identified.This method has high accuracy and simple calculation,providing a certain reference and reference for the treatment of water damage in goaf of similar test mines.
near horizontaldirectional drilling in goafselection method
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