A short wooden plug fixed in the roof, to which lines are hung, or to
serve as a bench mark for surveys. Fay
a. A mineral or group of consolidated minerals either in mass or in a
fragment of pebble or larger size. AGI
b. A stony meteorite.
c. A cut and polished gem or other precious mineral (but not a synthetic
compound used in ornamentation).
d. Crushed or naturally angular particles of rock that will pass a 3-in
(7.6-cm) sieve and be retained on a No. 4 U.S. Standard sieve.
ASCE
See:dirt band
Eng. Interbedded layers of sandstone and shale, or for a rock (such as
siltstone) intermediate between a sandstone and a mudstone. AGI
a. A variety of halotrichite. Syn:rock butter
b. A variety of alum.
c. A variety of clay.
Eng. Very hard underclay (clunch) with interbeds of sand. AGI
a. Wales. Anthracite, in lumps; also certain other very hard varieties of
coal. Fay
b. Mineral coal, as distinguished from charcoal; esp., in England, hard or
anthracite coal. Standard, 2
c. Sometimes applied to anthracite on account of its hardness.
See also:anthracite
d. Early term for anthracite. Korson
See:diamond content
See:diamond count
a. In the quarry industry, a person who lifts blocks of stone and boxes of
broken stone with a guy derrick in a quarry. Also called stone hoist
operator. DOT
b. In the stonework industry, one who lifts and moves blocks of stone with
an electric bridge crane in a stone mill. DOT
a. Person whose occupation is cutting stone; a stone mason.
Standard, 2
b. A gem cutter. Standard, 2
c. A machine for facing stone. Standard, 2
A drift excavated in rock, such as from the surface down to a coal seam.
See also:hard heading; rock drivage; slant. Nelson
a. In coal mines any inert dust spread on roadways as a defense against
the danger of coal dust explosions. The stone dust used is of a type that
does not cake in mine air. Ground limestone is satisfactory in most
conditions. About 5% less limestone is required than shale, and gypsum has
about two to three times the efficiency of shale. Gypsum appears to owe
its high efficiency to its hydrate water. Inert dusts are effective
because they absorb heat that the coal dust would otherwise receive from
the flame. See also:dust consolidation
b. Shale dust. Mason
c. Loosely applied to any incombustile dust used to render coal dust
incombustible. Mason
A device erected at strategic points in mine roadways for the purpose of
arresting explosions. Consists essentially of trays loaded with stone
dust, which are upset or overturned by the pressure wave in front of an
explosion ahead of the flame, producing a dense curtain or cloud of inert
dust to blanket the flame and stop further propagation of the explosion.
See also:colliery explosion; flame inhibitor. Sinclair, 1
The person in charge of stone dusting in coal mines. Nelson
The systematic distribution of stone dust along mine roadways to cover the
coal dust and reduce its flammability. Although stone dusting may not
always stop an explosion, it is less violent with stone dusting than
without. Safety regulations in many countries require that stone dust be
applied either mixed with the coal dust along mine roadways or as stone
dust barriers, to reduce the liability of coal-dust explosions.
Nelson; Roberts, 1
See:diamond exposure
See:block field
An early name for asbestos.
In bituminous coal mining, person who removes stone and other refuse from
coal mine floors and dumps refuse into mine cars for disposal. DOT