The sudden release of the weight of the rocks over a coal seam or of
enormous lateral stresses due to structural or tectonic folds and thrusts
and sometimes both. A rock bump may take the form of a pressure bump or a
shock bump. Nelson
A sudden and often violent breaking of a mass of rock from the walls of a
tunnel, mine, or deep quarry, caused by failure of highly stressed rock
and the rapid or instantaneous release of accumulated strain energy. It
may result in closure of a mine opening, or projection of broken rock into
it, accompanied by ground tremors, rockfalls, and air concussions.
See also:burst; pressure bump. AGI
A soft yellowish mixture of alum with aluminum and iron oxides; a
decomposition product of aluminous rocks. See:stone butter
Standard, 2
See:car runner
A machine used in quarrying for cutting an artificial seam in a mass of
stone. It is made in several forms, the principal types being the bar
channeler (in which the cutters are mounted on a carriage that works along
a heavy bar or bars) and the track channeler. Standard, 2
See:chute; rock hole. Also called slate chute.
The property or tendency of a rock to split along closely spaced planar
structures, produced by deformation or metamorphism.
See also:schistosity
See:roller bit
In anthracite coal mining, one who contracts to mine rock, as
distinguished from coal, at a certain price per ton or footage of advance.
DOT
A light-colored variety of asbestos. Syn:mountain cork; rock leather.
Standard, 2; Fay
Thickness of consolidated rock above the roof of an opening (equivalent to
cover, minus depth of weathering or of other soil). CF:cover
A machine for reducing rock or ore to smaller sizes. Three principal types
are the jaw crusher, the gyratory, and the hammer crusher.
a. Transparent quartz. ASTM
b. Highly polished brown glassware, hand-cut or engraved. ASTM
A way, esp. for a railroad, cut through a rock or rocky formation.
Mathews
See:cuttings; sludge.
A sequence of events involving the formation, alteration, destruction, and
reformation of rocks as a result of such processes as magmatism, erosion,
transportation, deposition, lithification, and metamorphism. A possible
sequence involves the crystallization of magma to form igneous rocks that
are then broken down to sediment as a result of weathering, the sediments
later being lithified to form sedimentary rocks, which in turn are altered
to metamorphic rocks. AGI
a. A dredge that excavates rock for the purpose of deepening harbors and
waterways; also, a device for sampling underwater outcrops and boulders.
b. A general term for a seabed sampling device consisting of a heavy
bucket frame that is pulled across the seabed on a cable controlled by a
winch operator on deck.
A horizontal mine passage cut in rock, esp. along a vein on a principal
level of a mine. See:crosscut; stope.
a. A machine for boring relatively short holes in rock for blasting
purposes. It may be a sinker, jackhammer, drifter, or stoper.
See also:percussive drill; rotary drill. Syn:Waugh drill
Nelson
b. A roller bit. Long
c. A conical bit for drilling hard rock. AGI
See:rock bit