Design of Directional Long Drilling Layer Layout for Roof and Analysis of Gas Extraction Effect
In response to the problems of large gas emission and high gas concentration in the return air corner during the mining period of the 3206 working face,it is proposed to apply directional long drilling to gas extraction in the goaf,and control the gas concentration in the return air corner by effectively intercepting gas emission.By using theoretical analysis methods and combining with on-site conditions,the layout position of directional long boreholes on the roof was reasonably determined,and specific layout parameters were provided.After engineering application,the directional long drilling on the roof achieved a gas extraction purity of 5～6 m3/min during the stable stage,and the gas concentration in the return air corner was between 0.3%and 0.5%.The fluctuation of gas extraction volume and gas concentration in the drilling and return air corner was relatively small,and good results were achieved in on-site gas extraction.
coal mininggas in goafreturn air cornerdirectional long drillingfissure gas
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