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。

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Rig GFC-120 is a kind of self moving reverse circulation rotary rigs. It is mainly used to drill side foundation holes and small water wells.

GFC-120型钻机为自走式动力头回转反循环钻机，用于降水井和护坡桩基础孔以及小型水井的施工。

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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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During the third quarter, the company continued what it described as an aggressive drill campaign with 13 core and 10 reverse circulation rigs in operation.

FORBES: Kinross: Tasiast-Expansion Commitment To Hit $1 Billion By Year-End; Production Set For 2014