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在煤系地层应用ＤＨＤ－３４０Ａ及ＤＨ４型风动冲击器河南煤田地质局李云峰河南煤系地层中，平顶山砂岩比较坚硬，一般厚度４０～１２０ｍ，其可钻性达９～１０级。岩石成份以细一粗粒长石石英为主，硅质胶结，坚硬，研磨性强，裂隙发育，破碎。浅部地层倾角大，容易孔斜...
Application of DHD-340A and DH4 Wind-induced Impactors in Coal-bearing Strata In Pingdingshan, Henan coalfield strata, Henan Coalfield Geology Bureau, the sandstone in Pingdingshan is relatively hard with a thickness of 40 ~ 120m and a drillability of 9 ~ 10. Rock composition of coarse and fine coarse feldspar quartz, siliceous cemented, hard, abrasive, crack development, broken. Tilt shallow layer, easy hole inclined ...