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| Damp |
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Gases (other than air) in mines, usually in dangerous concentrations. Prefixes are attached to indicate various gases and situations (Black damp, white damp, fire damp, after damp, stink damp)
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| De-superheater |
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A device for removing the excess heat in steam as its pressure is reduced.
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| De-vent |
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To close the vent connection of a pressure control valve permitting the valve to function at its adjusted pressure setting.
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| Deadband |
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The region or band of no response where an error signal will not cause a corresponding actuation of the controlled variable.
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| Decompression |
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The slow release of confined fluid to gradually reduce pressure on the fluid.
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| Delta |
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The amount of change in a number, size or position.
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| Deposit |
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Natural mineralization under the ground in sufficient quantities to warrant further exploration.
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| Detectors |
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Chemical or electronic instruments used to detect dangerous concentrations of mine gases.
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| Detonator |
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Device containing a small charge used to detonate an explosive. Types include: blasting caps, delay electric blasting caps, exploders, electric detonators, etc.
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| Development drilling |
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Drilling for the purpose of accurately estimating mineral reserves.
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| Diamond |
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Hardest known mineral, composed of pure carbon.
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| Differential current |
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The algebraic summation of the current in the torque motor; measured in MA (milliamperes).
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| Differential cylinder |
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Any cylinder in which the two opposed piston areas are not equal.
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| Diffusion |
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Movement of moisture from areas of high to low concentration or temperature.
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| Dilution |
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Waste rock that is unavoidably removed and mixed in with the ore. This lowers the grade of the ore.
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| Directional valve |
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A valve which selectively directs or prevents fluid flow to desired channels.
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| Disseminated ore |
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Ore spread more or less uniformly through the waste rock (gangue). Opposite of Massive ore.
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| Dither |
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A low amplitude, relatively high frequency periodic electrical signal, sometimes superimposed on the servo valve input to improve system resolution. Dither is expressed by the dither frequency (Hz) and the peak-to-peak dither current amplitude (ma).
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| Dore |
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Unrefined gold or silver bullion bars which still need further processing to become pure metal.
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| Dragline |
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Large surface mining equipment used to remove overburden above a deposit. Has a long boom and large bucket which is thrown outwards, then dragged back towards the machine.
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| Drain |
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A passage in, or a line from, a hydraulic component which returns leakage fluid independently to reservoir or to a vented manifold.
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| Dredging |
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Process of using a machine to dig up and sift through placer deposits in a watercourse.
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| Dressing |
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Treatment of ores to concentrate their minerals into concentrates and to collect waste to be discarded as tailings.
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| Drill |
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Machine using rotation, percussion (hammering) or a combination of both to make holes.
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| Drill hole |
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A small diameter hole created when recovering a core for geological information. Also a hole used to plant explosives.
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| Dump |
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Waste material extracted during mining and placed on the surface in a large pile. Also known as a waste dump, pile, heap, tip, spoil, pike, etc. Also the actual act of unloading or the mechanism for unloading a load.
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| Dump truck |
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A large earth moving vehicle whose carrying box can be tilted to discharge its load.
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