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Automatic false rotary
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Patent number 7,681,631
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Issue date Mar 23, 2010
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Weatherford/Lamb, Inc.
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Allen Keith Thomas, Jr.
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E21 - EARTH DRILLING MINING
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Automatic false rotary
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Patent number 7,314,090
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Issue date Jan 1, 2008
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Weatherford/Lamb, Inc.
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Allen Keith Thomas, Jr.
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E21 - EARTH DRILLING MINING