About 25, 000 wells a year are being fracked, a process in which water, chemicals and sand are injected at high pressure underground to release trapped natural gas.

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Lufkin, based in Lufkin, Texas, makes pumping equipment that helps drillers extract more oil out of older fields or ones that need to be pumped because the oil and gas underground is not under enough pressure to be forced to the surface naturally.

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Fracking uses high-pressure liquid pumped deep underground to fracture shale rock and release gas.

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But perhaps frackers, who inject high-pressure fluid into rocks deep underground to release natural gas, are beginning to improve themselves.

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Mudrian says that, freed from the pressure of the mainstream, metal went underground.

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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.

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The underground storage areas are created by removing salt in the rock strata with equipment similar to high pressure water jets.

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The assertion is that hydraulic fracturing fluids, which are injected at high speed and high pressure to create cracks in the shale rock that traps natural gas, will seep into underground water aquifers.

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