- 行业: Mining
- Number of terms: 33118
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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 ...
A rounded quartz pebble representing a quartz crystal that has lost its brilliancy and angular form; in gravels, once believed to be a fabulous stone obtained from the head of a flying dragon.
Industry:Mining
A rounded stone or pebble, commonly highly polished, from the stomach of some reptiles, esp. dinosaurs, plesiosaurs, and crocodilians. Gastroliths are thought to have been used in grinding up food, but marine reptiles may have used them to provide body stability while in the water.
Industry:Mining
A rounded, pillowlike body or mass of sandstone occurring within or just above finergrained sediment or commonly within the basal part of a sandstone overlying shale or mudstone. Its shape approaches that of an elongate, flattened ellipsoid (short axis more or less vertical), and is presumed to have formed by deformation, such as by large-scale load casting or mud flowage accompanied by subaqueous slump or foundering of sand channels.
Industry:Mining
A rounded, waterworn stone, esp. of the size suitable for paving; a cobble; also called cogglestone. Same as cobblestone.
Industry:Mining
A route constructed to enable plant, supplies, and vehicles to reach a mine, quarry, or opencast pit. In remote and isolated regions, the provision of an access road may be very costly.
Industry:Mining
A row of caps placed on blocks about 14 in (36 cm) high placed on top of the drift sets when constructing the permanent floor in the stope. Round poles are then laid lengthwise of the stope on the sheeting caps and are covered with lagging.
Industry:Mining
A row of rigid timber or steel props or chocks set along the edge of the waste and parallel to the longwall face to induce the roof beds to break and to secure caving of the waste area.
Industry:Mining
