This allows the bit to drill around a central cylinder of rock, which is taken in through the bit and into the core barrel.

这样允许钻头围绕岩石的中心圆柱体钻进，并通过钻头进入取芯桶。

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To drill soft, unconsolidated, usually shallow formations by eroding the "rock" below the bit by hydraulic impact loading alone.

钻进松软、非固结，通常是浅地层时，通过仅仅依靠液力冲击载荷去冲蚀破碎钻头下的岩石。

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Single pass drilling apparatus, use a one-piece drill bit, method and rock bolt for single pass rock bolting.

单通道钻孔装置，整个钻头的使用，用于单通道岩石锚固的方法和岩石锚栓。

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But for shale gas, once the drill reaches the shale rock underground, the drill bit is turned horizontally to bore a well that stretches through the natural gas producing shale.

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