- 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 natural hydrated calcium borate, Ca<sub>2</sub>B<sub>6</sub>O<sub>11</sub>.5H<sub>2</sub>O ; white or colorless; white streak; vitreous to dull luster; Mohs hardness, 4 to 4.5; sp gr, 2.26 to 2.48; found in California. One of the raw materials in the United States for boric acid, sodium borate, etc.
Industry:Mining
A natural mixture of the rare-earth metals cerium, lanthanum, and didymium; e.g., the waste matter from monazite sand after the extraction of thoria may contain large quantities of ceria, lanthana, didymia, yttria, and other substances. This is reduced to the metallic state by converting the oxides to chlorides, and then recovering the metal by electrolysis. The material obtained is an alloy containing about 50% cerium and 45% lanthanum and didymium.
Industry:Mining
A natural mound or exposed face of gravel, particularly such a place from which gravel is dug; a gravel pit.
Industry:Mining
A natural region within which some or all of the igneous rocks present certain wellmarked peculiarities in their mineralogical and chemical composition, structure, texture, etc., that set them apart from rocks of other petrographic provinces. Consanguineous, comagmatic.
Industry:Mining
A natural region within which some or all of the igneous rocks present certain wellmarked peculiarities in their mineralogical and chemical composition, structure, texture, etc., that set them apart from rocks of other petrographic provinces. Consanguineous, comagmatic.
Industry:Mining
A natural spun glass formed by blowing-out during quiet fountaining of fluid lava, cascading lava falls, or turbulent flows, sometimes in association with Pele's tear pyroclast. A single strand, with a diameter of less than 1/2 mm, may be as long as 2 m. Etymol: Pele, Hawaiian goddess of fire.
Industry:Mining
A naturally occurring soft paraffin wax; forms veinlike masses in ironstone nodules associated with coal-bearing strata, South Wales; in limestone cavities, France.
Industry:Mining
