a. In special application to mining, cooling of air before release in
lowest levels of deep, hot mine; also, expansion of compressed air for the
same purpose.
b. The process of absorption of heat from one location and its transfer to
and rejection at another place; arbitrarily expressed in units of (short)
tons and is equal to the coil cooling load divided by 12,000; 1 st (0.9 t)
of ice in melting in 24 h liberates heat at the rate of 200 Btu/min (211
kJ/min), or 12,000 Btu/h (1.27 MJ/h). Hartman, 1
a. A surface plant to form the protective barrier of frozen ground in the
freezing method of shaft sinking. The cooling agent used is ammonia which,
in its gaseous state, is compressed to about 120 psi (827 kPa) when it
passes to the top of the condensers, emerging at the bottom as liquid
ammonia under pressure. It then passes through a regulator valve into the
coolers where it immediately evaporates. The latent heat of evaporation is
extracted from the brine circuit--the brine being passed through the
coolers by the brine pumps. The ammonia gas passes back for re-use. The
brine emerges from the coolers at a temperature of -4 degrees F (-21.7
degrees C) and is pumped down the boreholes to freeze the water around the
shaft sinking.
b. A surface plant to cool liquids. These liquids or ice are sent
underground to cool the air current in heat exchangers. By this method,
the air in deep mines is cooled considerably and the working environment
is improved. See also:deep mining
An airtight, fire-resistant room in a mine used as a refuge in emergencies
by miners unable to reach the surface. MSHA, 4
A place formed in the side of an underground haulageway in which a worker
can take refuge during the passing of a train, or when shots are fired.
Also called refuge stalls. See also:manhole
A condition arrived at when driving pipe, casing, piling, etc., when it
cannot be driven to a greater depth or made to penetrate the ground a
distance of more than 1 ft (30.5 cm) per 100 blows delivered by a drive
hammer. Long
a. Waste material in the raw coal that has been removed in a cleaning or
preparation plant.
b. Notably used to describe colliery rejects; also called tailings.
Pryor, 3
An adaptation of a drag chain conveyor.
Pipes used on some washboxes instead of a refuse worm. BS, 5
See:reject elevator
That part of the washbox into which the refuse extractor discharges.
BS, 5
A device used in a washbox to remove the reject from the washing
compartments, operated manually or automatically. BS, 5
A reject gate in the form of a rotary (or star) valve. BS, 5
A screw conveyor fitted at the bottom of some washboxes to collect the
fine reject which has passed through the apertures in the screen plate.
BS, 5
The old doctrine that all mineral wealth was the prerogative of the crown
or the feudatory lord. The concession system, in which the state or the
private owner has the right to grant concessions or leases to mine
operators at discretion and subject to certain general restrictions, had
its origin in this doctrine. Almost all mining countries of the world,
except the United States, follow this system. Hoover
See:Indian jade
Anhydrite produced by dehydration of gypsum that itself was generated by
the hydration of anhydrite.
Medium obtained from the medium recovery system and purified (wholly or
partly) from contaminating fine coal and clay. BS, 5
a. In mineral leaching, reconstitution of barren leach solution after it
has completed its chemical attack on mineral and its values have been
removed. The regeneration of ion exchange resins and activated carbons by
the removal of elements or compounds from extraction sites on the resins
by special eluants. Pryor, 3
b. A reversing heat exchanger for preheating combustion air (and gaseous
fuels) from waste heat of the exhaust gases. Van Vlack
Separate compartments connected with a furnace; they are arranged for
preheating the gas and the air used for fuel. Mersereau, 2
A furnace in which hot gases, usually waste combustion gases, pass through
a set of chambers containing firebrick structures, to which the sensible
heat is given up. The direction of hot-gas flow is diverted periodically
to another set of chambers and cold incoming combustion gas or air is
preheated in the hot chambers.
See:recuperator