Application of directional fracturing softening technology in coal seams——A case study of Ningtiaota Coal Mine
Hard coal seam has the characteristics of high hardness,dense structure,poor permeability,etc.,but there are some problems in mining hard coal seam,such as low mining efficiency,large cutting loss and large coal dust concentration.In order to reduce the hardness of the coal body,destroy the internal structure and weaken the flying of coal dust,this paper uses kilometer directional drilling to construct drilling,uses high pressure pump to inject water into the seam,and softens the coal body through hydraulic fracturing to improve the working environment of the working face.Taking the S1206 working face of Ningtiaota Coal Mine as the research object,16 drilling holes with a depth of 350 m and a spacing of 20 m were con-structed within the cutting eye of the working face to the direction of the retreat channel,and high pressure hole seals were inserted.The backward fracturing method of fracturing once every 3m was used to soften the coal seam.The results show that the technology has low construction difficulty and high construction efficiency,which can increase the mining efficiency by 17％,reduce the pick loss rate by 109％,and restrain the coal dust flying to some extent.
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