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Rolling heel, forward facing rowing system
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Multiple cam directional controller for steerable rotary drill
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Method and apparatus for drill stem data transmission
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Method for near field electromagnetic proximity determination for guidance of a borehole drill
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Downhole electrode for well guidance system
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Method and apparatus for producing parallel boreholes
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Rotating magnet for distance and direction measurements from a first borehole to a second borehole
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Single-wire guidance system for drilling boreholes
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Solenoid guide system for horizontal boreholes
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Measurement of vector components of static field perturbations for borehole location
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Method and apparatus for measuring distance and direction by movable magnetic field source
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Two-source magnetic field guidance system
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Alternating and static magnetic field gradient measurements for distance and direction determination
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Borehole guidance system having target wireline
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Method for determining the location of a deep-well casing by magnetic field sensing
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