The practical testing indicates that the system has an evident electricity-saving effect while ensuring a safe underground operation.

实际测试表明，在给井下安全作业带来了可靠保证的同时，节电效果明显。

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The phenomenon of reservoir permeability decrease caused by drilling, completion and other underground operation is known as formation damage.

在钻井、完井等井下作业过程中，造成油气层渗透率下降的现象通称为油气层损害。

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Xinpu Phosphate Mine, medium and small-sized, features Complicated hydrogeological conditions and Marine sludge and heaving sand menacing underground operation.

新浦磷矿为一水文地质条件较复杂，海淤、流砂威胁井下开采的中小型矿山。

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The workers were constructing a mining operation underground when they were hit by a high-pressure release of grout, said Bronson Mack of the Southern Nevada Water Authority, a cooperative public agency formed in 1991 to manage the water resources in a region that includes Las Vegas.

CNN: STORY HIGHLIGHTS

Nerves remain badly rattled by a three-stage missile they fired over Japan last year, and talks to gain access to a Northern underground facility suspected of harboring a secret nuclear operation drag on.

CNN: TACKLING A CONUNDRUM

In the summer the RMT claimed London Underground (LU) planned to move the entire Jubilee line to driverless operation within three years, with trials starting later this year, with other lines to follow.

BBC: Strike ballot over tests for driverless Tube trains