- 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 ...
Rocklike clay, formed by the decomposition of basalts in situ. Compare: graywacke
Industry:Mining
Rocks and minerals not produced as sources of the metals, but excluding mineral fuels.
Industry:Mining
Rocks composed of particles derived from the erosion or weathering of preexisting rocks, such as residual, chemical, or organic rocks formed of detrital, precipitated, or organically accumulated materials; specif., clastic sedimentary rocks.
Industry:Mining
Rocks consisting of loosely coherent or uncemented particles, whether occurring at the surface or at depth.
Industry:Mining
Rocks formed by the accumulation of sediment in water (aqueous deposits) or from air (eolian deposits). The sediment may consist of rock fragments or particles of various 2815 sizes (conglomerate sandstone, shale); of the remains or products of animals or plants (certain limestones and coal); of the product of chemical action or of evaporation (salt, gypsum, etc.); or of mixtures of these materials. Some sedimentary deposits (tuffs) are composed of fragments blown from volcanoes and deposited on land or in water. A characteristic feature of sedimentary deposits is a layered structure known as bedding or stratification. Each layer is a bed or stratum. Sedimentary beds as deposited lie flat or nearly flat. See: stratified rocks
Industry:Mining
Rocks in which the crystals are very fine-grained, or else the whole or part is glass. These are the volcanic rocks.
Industry:Mining
Rocks of this group are usually carbonate of iron that has partially or wholly replaced limestone.
Industry:Mining
Rocks older than the Cambrian age. Name refers to the great shield-shaped areas of ancient mineral-bearing rocks. These ancient rocks occur in many parts of the world.
Industry:Mining
Rocks produced by contact metasomatism. They include both the border rocks of the intrusion and metamorphosed or recrystallized portions of the intruded rocks, esp. limestone.
Industry:Mining
