Application Analysis of Large-diameter Drilling in Gas Extraction in Goaf
In order to solve the problems of high cost and large amount of treatment engineering in the gas extraction of goaf through connecting tunnels and buried pipes in the 3306 fully mechanized mining face,it is proposed to apply large-diameter drilling to gas treatment in goaf.Specifically,in the 3306 measure lane,Φ650 mm large diameter drilling is arranged at intervals of 30 meters.Negative pressure and high flow pumping within a range of 5～35 meters after drilling into the goaf is carried out.After on-site application,the gas extraction concentration of large-diameter boreholes remained stable at 2.3％～3.8％,the pure gas extraction volume remained stable at 4.9～6.5 m3/min,and the gas concentration at the return air corner of the mining face was controlled at 0.2％～0.6％.The gas concentration at the return air corner was within a safe range,indicating that the gas treatment in the goaf using large-diameter boreholes on site has achieved good results.
large diameter drillinggas controlgoafreturn air corner
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