a. The decrease in volume of a soil or fill material through the reduction
of voids by mechanical compaction, superimposed loads, or natural
consolidation. Nelson
b. The settling or reduction in volume of earthen fills, cement slurries,
or concrete on setting. Long
c. In bitmaking by the powder-metal processes, the difference between the
dimensions of the finished bit crown and those of the bit mold.
Long
d. The decrease in volume of clayey soil or sediment owing to reduction of
void volume, principally by drying. AGI
A void left in cast metals as a result of solidification shrinkage.
ASM, 1
A crack produced in fine-grained sediment or rock by the loss of contained
water during drying or dehydration; e.g., a desiccation crack or a mud
crack. AGI
The numerical difference between the plastic and shrinkage limits.
ASCE
One in which only part of the severed ore is removed during stoping, the
balance being temporarily available as support of workings. Used in
steeply dipping lodes with strong walls. Pryor, 3
A vertical, overhand mining method whereby most of the broken ore remains
in the stope to form a working floor for the miners. Another reason for
leaving the broken ore in the stope is to provide additional wall support
until the stope is completed and ready for drawdown. Stopes are mined
upward in horizontal slices. Normally, about 35% of the ore derived from
the stope cuts (the swell) can be drawn off ("shrunk") as mining
progresses. As a consequence, no revenues can be obtained from the ore
remaining in the stope until it is finally extracted and processed for its
mineral values. The method is labor intensive and cannot be readily
mechanized. It is usually applied to orebodies on narrow veins or
orebodies where other methods cannot be used or might be impractical or
uneconomical. The method can be easily applied to ore zones as narrow as 4
ft (1.2 m), but can also be successfully used in ore widths up to 100 ft
(30 m). Syn:shrinkage with waste fill
See:longwall
A rope of four strands laid around a core. Zern
A hard black amorphous material containing >98% carbon, interbedded among
Precambrian schists; probably the metamorphic equivalent of bitumen, but
possibly merely impure graphite. Also spelled schungite.
A connection between two wires of a blasting cap that prevents building up
of opposed electric potential in them. Nichols, 1
A track arrangement for bringing a wagon or mine car to another track
without the need for a curve, turntable, or traverser. Also called back
shunt; switchback. Nelson
One of the rate provisions in drilling contracts, specifying the
compensation to the independent drilling contractor when drilling
operations have been suspended at the request of the operator.
Williams
See:chute
A device by means of which the flow of gas or fluid can be made to
cease--usually not with the intention of metering or regulating the flow.
Long
Scot. Movable or hinged supports for the cage at a shaft landing. Also
called keps; keeps; chairs; dogs; seats.
A back-and-forth motion of a machine that continues to face in one
direction. Nichols, 2
A vehicle on rubber tires or continuous treads to transfer raw materials,
such as coal and ore, from loading machines in trackless areas of a mine
to the main transportation system. See also:rubber-tired haulage;
trackless tunneling. Nelson
In bituminous coal mining, one who drives an electrically powered truck
(shuttle car) in a coal mine to transport coal from the excavation point
to the conveyor belt. DOT
a. A conveyor that is moved forward or backward in normal operation to
vary the loading or discharge points, or both. It may be designed to move
only in a straight path, or in either a straight or a curved path.
See also:movable conveyor
b. Any conveyor, such as belt, chain, pan, apron, screw, etc., in a
self-contained structure movable in a defined path parallel to the flow of
the material.
shuttle multispectral infrared radiometer