我矿区部分石英砂岩常为7-9级,破碎程度严重,岩矿心不易采取,常有造成补孔的危险。该地层如果采用合金单管或合金双管钻进是克取不下的。单管钢砂钻进,效率虽高,但岩心几乎全取不上。我们采取了反循环钻进,常受地层漏水所限制,或将岩心破碎成小块,在岩心管中混在一团。分不清层次,不 Part of my quartzite sandstone mining area is often 7-9, a serious degree of fragmentation, rock core hard to take, often causing the danger of make up holes. The strata if the alloy single tube or alloy double pipe drilling can not take off. Single pipe grit drilling, although the high efficiency, but almost impossible to get the core. We have adopted reverse circulation drilling, which is often limited by water leakage in the formation or broken into small pieces in the core tube. Can not tell level, no