Apply air reverse circulation drilling, appropriate increase length of twofold wall drill tools under certain conditions, may be drilling much deeper.
运用气举反循环钻进，在满足一定条件下适当增加双壁钻具长度即可得到较大钻进孔深。
The measures to control construction quality are analyzed, which are used to drill deep holes with normal circulation slewing drilling machine.
分析了正循环回转钻深孔施工的施工方法和要点，提出了施工监理的监理质量控制点及注意事项。
According to the exploration problems in an open-pit mine, a new drilling method using reverse circulation DTH hammer drill is put forward.
针对露天矿钻探施工中存在的问题，提出了利用贯通式反循环潜孔锤进行施工的新方法。
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