Research on gas extraction technology of directional long drilling in roof based on UDEC
In order to effectively solve the problems of large gas emission in the goaf of the No.2301 working face of the Main Coking Coal Industry,which is prone to cause gas exceeding the limit in the upper corner,a design was used to extract gas from the goaf by u-sing roof overlong directional high-level drilling.The selection of the layer of high-level drilling directly affects the gas extraction effect.Based on the UDEC numerical simulation software,the vertical distribution of"three zones"in the goaf was studied.It was calculated that the height range of roof fracture zone was 17～35 m,and the key layer was 8～17 m above the roof.Placing holes within an area of 17～35 m above the roof helped to protect the drilling from damage.Roof directional high-level long drilling gas extraction could effec-tively improve the extraction efficiency,and the gas extraction effect was obvious,realizing the goaf of"replacing roadway with hole",in-vestigating the gas extraction purity and gas concentration of the directional high-level long drilling of the roof,and comparing it with the extraction effect of the drilling through the floor,and measuring the change of residual gas content after extraction,the advantages of gas extraction from the directional long drilling of the roof were verified.Roof directional high-level long drilling instead of high extraction roadway technology has strong feasibility and broad application prospects.
high-level drillinggas extractionupper cornerU DEC numerical simulation"three zones"of goaf
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