- 行业: Mining
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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 ...
The second moment of area about an axis perpendicular to its plane is known as the polar moment of inertia of a plane section.
Industry:Mining
The second period of the Cenozoic era, following the Tertiary; also, the corresponding system of rocks. It began 2 to 3 million years ago and extends to the present. It consists of two grossly unequal epochs; the Pleistocene, up to about 10,000 years ago, and the Holocene since that time. The Quaternary was originally designated an era rather than a period, with the epochs considered to be periods, and it is still sometimes used as such in the geologic literature. The Quaternary may also be incorporated into the Neogene, when the Neogene is designated as a period of the Tertiary era.
Industry:Mining
The second period of the Mesozoic Era (after the Triassic and before the Cretaceous), thought to have covered the span of time between 190 million years and 135 million years ago; also, the corresponding system of rocks. It is named after the Jura Mountains between France and Switzerland, in which rocks of this age were first studied.
Industry:Mining
The secondary grinding of coal or ore by tumbling in a revolving cylinder with no balls or bars taking part in the operation.
Industry:Mining
The section of a mine shaft used for hoisting the mineral to the surface.
Industry:Mining
The section of a mine shaft used for raising and lowering miners.
Industry:Mining
The sections into which a washbox is divided by transverse division plates that extend above the screen plate to form a weir; each compartment usually comprises two or more cells.
Industry:Mining
The sediment and rock mass underlying the coastal plain, the continental shelf, and the continental slope.
Industry:Mining
The selection by hand of pieces of coal with certain specific qualities according to surface appearance.
Industry:Mining
