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List Of Articles : G |
Gallery
A horizontal or a nearly horizontal underground passage, either natural or artificial.
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Gangue
The worthless minerals in an ore deposit.
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Gasification
Any of various processes by which coal is turned into low, medium, or high Btu gases.
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Gathering conveyor; gathering belt
Any conveyor which is used to gather coal from other conveyors and deliver it either into mine cars or onto another conveyor. The term is frequently used with belt conveyors placed in entries where a number of room conveyors deliver coal onto the belt.
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Geologist
One who studies the constitution, structure, and history of the earth's crust, conducting research into the formation and dissolution of rock layers, analyzing fossil and mineral content of layers, and endeavoring to fix historical sequence of development by relating characteristics to known geological influences (historical geology).
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Global climate change
This term usually refers to the gradual warming of the earth caused by the greenhouse effect. Many scientists believe this is the result of man-made emissions of greenhouse gases such as carbon dioxide, chlorofluorocarbons (CFC) and methane, although there is no agreement among the scientific community on this controversial issue.
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Goaf
the caved area behind a longwall (see Longwall).
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Gob
The term applied to that part of the mine from which the coal has been removed and the space more or less filled up with waste. Also, the loose waste in a mine. Also called goaf.
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Gold loan
A form of debt financing whereby a potential gold producer borrows gold from a lending institution, sells the gold on the open market, uses the cash for mine development, then pays back the gold from actual mine production.
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Gold Precipitate
Fine sludge of gold, silver, and zinc. The precious metals are precipitated out of solution by the addition of fine zinc dust.
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Grade
The metal content of ore in Troy ounces per ton or percent. Head grade is the average grade of ore fed into a mill or heap leach metal recovery operation.
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Grain
In petrology, that factor of the texture of a rock composed of distinct particles or crystals which depends upon their absolute size.
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Gravity concentration
using the different densities of minerals to separate valuable minerals from rock, or from each other.
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Grinding
the process of reducing rock to flour-sized particles for further processing.
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Grizzly
A grating, usually constructed of steel rails, placed over the top of a chute or ore pass for the purpose of stopping large pieces of rock or ore that may hang up in the pass.
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Ground control
The regulation and final arresting of the closure of the walls of a mined area. The term generally refers to measures taken to prevent roof falls or coal bursts.
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Ground pressure
The pressure to which a rock formation is subjected by the weight of the superimposed rock and rock material or by diastrophic forces created by movements in the rocks forming the earth's crust. Such pressures may be great enough to cause rocks having a low compressional strength to deform and be squeezed into and close a borehole or other underground opening not adequately strengthened by an artificial support, such as casing or timber.
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Gunite
A cement applied by spraying to the roof and sides of a mine passage.
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Gyratory Crusher
A machine that crushes ore between an eccentrically mounted crushing cone and a fixed crushing throat. Typically, it has a higher capacity than a jaw crusher.
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