- 업종: Mining
- Number of terms: 33118
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- Company Profile:
The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A light-colored, vesicular, glassy rock commonly having the composition of rhyolite. It is often sufficiently buoyant to float on water and is economically useful as a lightweight aggregate and as an abrasive. The adjectival form, pumiceous, is usually applied to pyroclastic ejecta. Compare: scoria; pumicite.
Industry:Mining
A light-green variety of grossular garnet closely approaching fine jadeite in appearance, esp. that in Transvaal, South Africa.
Industry:Mining
A light-green, magnesium-rich clay mineral, named from its occurrence at Attapulgus, GA, where it is quarried as fuller's earth. Crystallizes in the monoclinic system.
Industry:Mining
A light-green, magnesium-rich clay mineral, named from its occurrence at Attapulgus, GA, where it is quarried as fuller's earth. Crystallizes in the monoclinic system.
Industry:Mining
A lightning gap is a break about 6 ft (1.8 m) long made at the mine entrance in blasting circuits, used in firing blasts from the outside, to prevent lightning discharges from following the circuits into the mine.
Industry:Mining
A lightweight compact alidade, with a low pillar and a reflecting prism through which the ocular may be viewed from above. As used by some geologists, it is commonly equipped with the Stebinger drum.
Industry:Mining
A lightweight dam constructed of repeated arches with axes sloping at about 45 degrees to the horizontal, the arches being carried on parallel buttress walls.
Industry:Mining
A lightweight inner container for explosive materials, usually encased in a substantial shipping container called a case.
Industry:Mining
A lightweight steel bar extending faceward from the steel supports behind the conveyor. It supports the area between the conveyor and the coal on longwall faces where cutter loaders are carried on armored flexible conveyors. The joint and locking device may consist of a hinge pin and wedge. The standard bar can carry in cantilever a maximum tip load of about 2 st (1.8 t). In general, linked bars are stronger than corrugated straps and wooden bars, and their use is increasing.
Industry:Mining
