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List Of Articles : F |
Face
The exposed area of a coal bed from which coal is being extracted.
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Face conveyor
Any conveyor used parallel to a working face which delivers ore into another conveyor or into a car.
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Fall
A mass of roof rock or coal which has fallen in any part of a mine.
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Fan signal
Automation device designed to give alarm if the main fan slows down or stops.
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Fan, auxiliary
A small, portable fan used to supplement the ventilation of an individual working place.
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Fan, booster
A large fan installed in the main air current, and thus in tandem with the main fan.
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Fault
A slip-surface between two portions of the earth's surface that have moved relative to each other. A fault is a failure surface and is evidence of severe earth stresses.
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Fault zone
A fault, instead of being a single clean fracture, may be a zone hundreds or thousands of feet wide. The fault zone consists of numerous interlacing small faults or a confused zone of gouge, breccia, or mylonite.
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Feasibility Study
An engineering study designed to define the technical, economic, and legal viability of a mining project with a high degree of reliability.
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Feeder
A machine that feeds coal onto a conveyor belt evenly.
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Fill
Any material that is put back in place of the extracted ore to provide ground support.
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Filter Press
A pressure filter containing cloth leaves which are supported within a closed container to remove solids from a fine solids feed slurry. The solids sludge collected is periodically removed from the filter by opening the filter plates, scraping off the solids and replacing the plates with new and clean filter cloth or filter paper for continued filtering.
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Fire damp
The combustible gas, methane, CH4. Also, the explosive methane-air mixtures with between 5% and 15% methane. A combustible gas formed in mines by decomposition of coal or other carbonaceous matter, and that consists chiefly of methane.
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Fissure
An extensive crack, break, or fracture in the rocks.
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Fixed carbon
The part of the carbon that remains behind when coal is heated in a closed vessel until all of the volatile matter is driven off.
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Float dust
Fine coal-dust particles carried in suspension by air currents and eventually deposited in return entries. Dust consisting of particles of coal that can pass through a No. 200 sieve.
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Floor
That part of any underground working upon which a person walks or upon which haulage equipment travels; simply the bottom or underlying surface of an underground excavation.
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Flotation
A milling process in which valuable mineral particles are induced to become attached to bubbles and float away from the waste particles in a solid/solution pulp.
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Flow-through shares
Shares in an exploration company that allow the tax deduction or credits for mineral exploration to be passed to the investor.
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Flue Gas Desulfurization
Any of several forms of chemical/physical processes that remove sulfur compounds formed during coal combustion. The devices, commonly called ‘scrubbers,’ combine the sulfur in gaseous emissions with another chemical medium (commonly lime) to form inert ‘sludge (gypsum)’ which must then be removed for disposal.
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Fluidized Bed Combustion
A process with a high degree of ability to remove sulfur from coal during combustion. Crushed coal and limestone are suspended in the bottom of a boiler by an upward stream of hot air. The coal is burned in this bubbling, liquid-like (or ‘fluidized’) mixture. Rather than released as emissions, sulfur from combustion gases combines with the limestone to form a solid compound recovered with the ash.
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Flux
A mix of chemical substances that react with gangue minerals to form slags, which are liquid at smelting furnace temperature and low enough in density to float on the molten bath of metal.
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Fly ash
The finely divided particles of ash suspended in gases resulting from the combustion of fuel. Electrostatic precipitators are used to remove fly ash from the gases prior to the release from a power plant's smokestack.
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Footwall
the rock which lies below the ore.
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Formation
Any assemblage of rocks which have some character in common, whether of origin, age, or composition. Often, the word is loosely used to indicate anything that has been formed or brought into its present shape.
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Fossil fuel
Any naturally occurring fuel of an organic nature, such as coal, crude oil and natural gas.
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Fracture
A general term to include any kind of discontinuity in a body of rock if produced by mechanical failure, whether by shear stress or tensile stress. Fractures include faults, shears, joints, and planes of fracture cleavage.
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Free milling
Ores of gold or silver from which the precious metals can be recovered by concentrating methods without resorting to pressure leaching or other chemical treatment.
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Friable
Easy to break, or crumbling naturally. Descriptive of certain rocks and minerals.
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Froth flotation
Most widely used process for extracting minerals from their ores. Froth flotation separates and concentrates valuable minerals by altering their surfaces so that they are either repelled or attracted by water. Unwetted particles, which adhere to air that is bubbled through the water, will float in the froth, while wetted particles will sink.
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Fuse
A cord-like substance used in the ignition of explosives. Black powder is entrained in the cord and, when lit, burns along the cord at a set rate. A fuse can be safely used to ignite a cap, which is the primer for an explosive.
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