Grizzly in which alternate bars rise and then fall gently, any required
lateral (conveying) movement being built into the mechanism, therefore
reducing loss of headroom in conveying and screening. Other types are
traveling bar, ring-roll, and chain grizzlies. Pryor, 3
S. Am. Volcanic mud, sometimes carbonaceous.
An iron with a sharp steel point, for driving into clefts when levering
off rock. Zern
An auger equipped with cutting blades; designed so that fluid, under
pressure, passing through inclined holes just above the blades, washes
away the material loosened by the blades, thereby cleaning the inside of
the casing without disturbing the material below the bottom of the casing
that is to be sampled. Long
The Mining Research Establishment of the National Coal Board, Great
Britain. Its prime purpose is to carry out tests and investigations aimed
at increasing the efficiency of coal production while maintaining a high
level of safety. Nelson
A high-air-pressure directional machine which operates in the manner of a
whitewashing machine and displaces coal dust from the roof and sides. This
machine carries 2 st (1.8 t) of stone dust, and traveling at 11 ft/min
(3.4 m/min) distributes over 26 lb/min (11.8 kg/min) of dust.
Sinclair, 1
This methane indicator is one in which the sample is made to flow
continuously over the filaments while the determination is being made. In
this case, two matched filaments form the adjacent arms of the bridge. One
of these is specially activated in order to burn the methane while the
other filament is inactive and operates at a somewhat lower temperature.
This arrangement is designed to compensate for changes in barometric
pressure, temperature, humidity, and the presence of carbon dioxide.
Facilities for adjustment are provided to compensate for zero drift and
change in battery voltage. The meter is provided with two shunts so that
two ranges are provided on the scale: 0% to 5% by 0.1% divisions and 0% to
2% by 0.02% divisions. Roberts, 1
Nonelectric, short-interval (millisecond, ms) delay device for use in
delaying a blast; initiated by detonating cord.
Apprev. for mean spherical candlepower. Mason
a. Unconsolidated soil, sand, clay, or loam encountered in surface mining;
generally, earth which can be moved without blasting. Pryor, 3
b. Useless material produced in mining. Syn:mullock
c. A layer of earth, sand or sediment lying immediately above the sand, or
gravel containing, or supposed to contain, gold in placer mining
districts; it may itself contain some traces of gold. Fay
d. Finely blasted rock, particularly from undergound. Nichols, 1
e. To excavate or remove muck from. Webster 2nd
Gray, forge pig iron melted in a puddling furnace, then balled, squeezed,
and rolled. Mersereau, 1
In bituminous coal mining, a person who is in charge of a crew of loaders
shoveling rock into cars during the driving of new underground passageways
from one part of the mine to another. DOT
In mining and quarrying, a laborer who (1) shovels ore or rock into mine
cars or onto a conveyor from which mine cars are loaded and at some point
are removed from the working face or surfaces of natural stone deposits;
or (2) works in a stope shoveling ore into chutes from which it is loaded
into cars on haulage level below. Also called car filler; rock passer;
shoveler. DOT
The operation of loading broken rock by hand or machine, usually in shafts
or tunnels. Nelson
Crude puddled iron ready for squeezing or rolling. Fay
Soft clay overlying or underlying coal.
A scaling or spalling hammer. Standard, 2
A saw using an uncharged blade, usually steel, which runs in a bath or
stream of carborundum abrasive. Also known as a mud saw.
Operations concerned with stripping overburden, valuable gravels, or sands
in exploitation of opencast mineral deposits. Pryor, 3
A soil that contains at least 50% organic matter that is well decomposed.
AGI