- 行业: Mining
- Number of terms: 33118
- Number of blossaries: 0
- 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 ...
One of six radioactive elements that occur naturally: potassium, rubidium, thorium, uranium, and associated radium, samarium, and lutecium. Thorium commonly occurs in 2538 monazite, a sparsely scattered accessory mineral of certain granites, gneisses, and pegmatites. It is concentrated, however, by weathering processes in sands and gravels as commercial placer deposits along rivers and beaches. The most important primary uranium ore minerals are davidite and uraninite, esp. pitchblende, the massive variety. These minerals are of rather underspread occurrence in certain granites and pegmatites and occur as secondary minerals in metallic vein deposits. The secondary uranium minerals, however, are more underspread and more numerous than the primary uranium ore minerals. Secondary uranium minerals are found in weathered and oxidized zones of primary deposits and, also, in irregular flat-lying sandstones, such as those in the Colorado Plateau, where the uranium mineralization was precipitated from solutions. Carnotite, the potassium uranium vanadate of conspicuous yellow color, is perhaps the most important of the secondary uranium ore minerals. Others are tyuyamunite, which is closely related to carnotite, and the torbernites and autunites which are uranium minerals.
Industry:Mining
One of the auxiliary rods at the top of a winding shaft for guiding and steadying the cages during decking or loading and unloading operations.
Industry:Mining
One of the best known overwinder prevention devices consists of two vertical-screwed spindles, each carrying two traveling nuts and chain driven from the drum shaft so as to rotate in opposite directions. The nuts are prevented from rotating by projections engaging with a fixed plate and therefore travel up and down according to the movement of the cages. The upper nut takes care of overwinding and the lower nut of overspeeding.
Industry:Mining
One of the constituent elementary particles of an atom. A charge of negative electricity equal to about 1.602 X 10<sub>-19</sub>C and having a mass when at rest of about 9.107 X 10<sub>-28</sub>g or 1/1,837 that of a proton. Electrons surround the positively charged nucleus of the atom and determine the chemical properties of the atom.
Industry:Mining
One of the directions in a crystal in which either tension or compression will cause the crystal to develop piezoelectric charges.
Industry:Mining
One of the finest and best known building stones to be found in the United States. It gets its name from its shipping point, Bedford, IN.
Industry:Mining
One of the firebrick supports built of arch brick or keys to support the checker work on the second, third, or fourth pass of hot-blast stoves.
Industry:Mining
One of the fittings bolted to the side of a cage to engage the rigid guides in a shaft. Usually there are two for each guide, one at the top and one at the bottom of the cage. The shoes are usually about 1 ft (0.3 m) long and shaped to fit closely around about three-quarters of the guide, with sufficient clearance for free movement but not sufficient to allow the shoe to come off the guide.
Industry:Mining
One of the high explosives used for mining and quarrying. They can be divided into four main classes: gelatins; semigelatins; nitroglycerin powders, and non-nitroglycerin explosives, including water gels, emulsions, and ANFO.
Industry:Mining
