The system of working one or more seams or beds of mineral by open working
or stripping in stages or steps. Syn:bench-and-bench
Forming frequent benches; said of a lode. Standard, 2
A jig fitted with a flexible rubber diaphragm that is worked by an
eccentric motion, thus producing a jigging cycle (pulsion suction).
See also:jig
The stress produced in the outer fibers of a rope by bending over a sheave
or drum. Zern
An idler pulley that is used solely for the purpose of changing the
direction of travel of the belt other than at the terminals of the
conveyor. NEMA, 2
The inside radius of a bent section. ASM, 1
Caisson disease, brought on by too sudden return to normal pressure after
working in a pressurized shaft or tunnel. Pryor, 3
A shaft that supports a bend wheel or pulley.
A tangent point where a bending arc ceases or changes. ASM, 1
A test for determining relative ductility of metal that is to be formed,
usually sheet, strip, plate, or wire, and for determining soundness and
toughness of metal. The specimen is usually bent over a specified diameter
through a specified angle for a specified number of cycles. ASM, 1
A wheel used to interrupt and change the normal path of travel of the
conveying or driving medium. Most generally used to effect a change in
direction of conveyor travel from inclined to horizontal or a similar
change.
To improve the grade by removing associated impurities; to upgrade.
a. The dressing or processing of coal or ores for the purpose of (1)
regulating the size of a desired product, (2) removing unwanted
constituents, and (3) improving the quality, purity, or assay grade of a
desired product.
b. Concentration or other preparation of coal or ores for smelting by
drying, flotation, or magnetic separation.
c. Improvement of the grade of coal or ores by milling, flotation,
sintering, gravity concentration, or other processes.
An archaic trade name for purple sapphire.
A hexagonal mineral, 2[BaTiSi3 O9 ] ; occurs in double
pyramids; colorless, white, or blue, resembling sapphire; in veins in
serpentine schist.
A monoclinic mineral, (Ag,Cu)3 (Bi,Pb)7 S12 .
A trigonal mineral, (Ba,Sr)6 (Ca,Mn)6 Mg(CO3 ) (sub
13) ; shows flat, simple rhombohedral crystals and cleavage; fluoresces
yellow or red; in veins with calcite.
a. In tunnel timbering, two posts and a roof timber. Nichols, 1
b. A transverse structure consisting of legs, bracing, and feet used for
the purpose of supporting a gallery or conveyor frame at a fixed
elevation.
A primary division of the sea that includes all of the ocean floor. The
Benthic Division is subdivided into the Littoral System (the ocean floor
lying in water depths ranging from the high watermark to a depth of 200 m
or the edge of the continental shelf), and the Deep-Sea System (ocean
floor lying in water deeper than 200 m). The systems are further
subdivided into the Eulittoral Zone (0 to 50 m), Sublittoral Zone (50 to
200 m), Archibenthic Zone (200 to 1,000 m), and the Abyssal-Benthic Zone
(1,000 m and greater). Hy
a. Refers to the bottom of a body of standing water. AGI
b. Pertaining to benthos; also, said of that environment. Syn:demersal
AGI
All plants and animals living on the ocean bottom. Hy