A system delivering coal more efficiently in which a string of cars, with
distinctive markings, and loaded to "full visible capacity," is operated
without service frills or stops along the way for cars to be cut in and
out, from the loading place to the point of delivery.
The monetary value of a mineral or rock product per ton or other unit of
measurement. See also:value
A system of ventilation in which each working face is ventilated by a
separate air current. BS, 8
a. Weight per unit of volume. See also:dry unit weight;
effective unit weight; maximum unit weight; saturated unit weight;
submerged unit weight; unit weight of water; wet unit weight;
zero air voids unit weight.
b. The density of a material. See also:density
The weight per unit volume of water; normally equal to 62.4 lb/ft (super
3) or 1 g/cm3 . See also:unit weight
a. Having a valence of one. Webster 3rd
b. Having one valence; e.g., calcium, which has only a valence of two.
Webster 2nd
universal arc-shearing machine
A machine with a rotating jib head so that vertical or shearing cuts can
be made in addition to the arc wall cut. An arcwall machine will cut a
12-ft (3.7-m) heading to a depth of 6 ft (1.8 m) in 10 min. Mason
A clamping device used on a drill column by means of which a horizontal
arm can be affixed at any point on the vertical section of a drill column.
Long
A coal cutter with a jib capable of cutting at any height or angle. It may
be mounted on crawler tracks. See also:universal machine;
turret coal cutter. Nelson
Coupling that joins two driving shafts that rotate about differently
slanted axes. Pryor, 3
Designed as an all-purpose mask for protection against a great variety of
toxic gases, vapors, and smokes, including carbon monoxide. It is equipped
with an indicator that shows at a glance the remaining service time of the
canister for carbon monoxide. This mask is particularly effective for
mines, fire fighting, and general industrial uses where the contaminants
are of relatively low content. Best, 1
These couplings are used where shafts intersect at any angle or where
pivoted members must be driven. If there is an offset in the two shafts,
or if one or both shafts must change location during operation, two of
these couplings are used, and one is fitted with a splined joint mating
with the connecting intermediate shaft to allow axial movement.
Pit and Quarry
See:lang lay rope
A power-driven coal cutter that will not only cut horizontal kerfs, but
will also cut vertical kerfs at any angle, and is designed for operation
either on track, crawler treads, or rubber tires.
Syn:universal coal cutter; arc shear machine.
An electric motor rated at less than 1 hp (746 W) output that operates on
either direct or alternating current. Hammond
Mixture of several indicator dyes, each of which changes color through a
specific pH range, so that by suitably combining a wide color change and
pH, a reading can be obtained. Pryor, 3
Indicator plant that is restricted exclusively to rocks or soils of a
definite mineral content and not found under any other conditions.
CF:local indicator plant
A stage of three, four, or five axes of rotation, attached to the rotating
stage of a polarized-light microscope, that enables a thin section or
mineral grain under study to be turned in a precisely controlled fashion
about three mutually orthogonal axes. It is used to determine precisely
the optical properties and parameters of minerals or their orientation in
a set of external coordinates. Syn:U-stage; Federov stage.
CF:goniometer; spindle stage.
An instrument so designed that it is capable of exerting a tensile,
compressive, or transverse stress on a specimen under test. Further, it
can be adapted for the determination of Brinell hardness, ductility, cold
bend, and other properties. The machine consists essentially of three
systems: loading, weighing, and indicating, the loading being applied
either mechanically or hydraulically. Osborne
A roll train having adjustable horizontal and vertical rolls, so as to
produce sections of various sizes. Fay
In attacking a rock face, the first effort of the miner is directed toward
making a cut that will permit the succeeding shots to exert the greatest
force with the minimum charge of explosive. In doing this unkeying, the
miner takes advantage of any persistent seam in the rock face.
Stauffer