- Settore: 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 ...
A coarse opaque variety of topaz from Finbo, Sweden. Also spelled physalite.
Industry:Mining
A coarse-fraction concentration method used in milling pebble phosphate in which conditioned feed at 70% to 75% solids is placed on a flat conveyor belt traveling at a rate of about 75 ft/min (22.9 m/min). Water sprayed on the surface of the pulp aerates the pulp, causing agglomerates of phosphate particles to float to the side of the belt for removal. The silica fraction travels the length of the belt and is permitted to flow off the opposite end. Baffles are positioned at appropriate points along the belt to stir the material so that trapped phosphate particles are given an opportunity to float. Concentrate from the first belts or rougher operation is cleaned on a second belt for further silica removal. Tailings from the cleaner belt are recycled to the rougher circuit.
Industry:Mining
A coarse-fraction concentration method used in milling pebble phosphate that is based on flowing reagentized feed over a submerged sloping, stationary screen. Agglomerated phosphate particles float on top of the screen and are recovered at the lower end. Sand particles pass through the screen and are removed as a tailings fraction. Each screen section is approx. 3 ft (0.9 m) wide by 4 ft (1.2 m) long and treats 2 to 3 st/h (1.8 to 2.7 t/h) of feed.
Industry:Mining
A coarse-grained clastic rock, composed of angular broken rock fragments held together by a mineral cement or in a fine-grained matrix; it differs from conglomerate in that the fragments have sharp edges and unworn corners. Breccia may originate as a result of talus accumulation, explosive igneous processes, collapse of rock material, or faulting. Etymol: Italian, broken stones, rubble.
Industry:Mining
A coarse-grained clastic rock, composed of angular broken rock fragments held together by a mineral cement or in a fine-grained matrix; it differs from conglomerate in that the fragments have sharp edges and unworn corners. Breccia may originate as a result of talus accumulation, explosive igneous processes, collapse of rock material, or faulting. Etymol: Italian, broken stones, rubble.
Industry:Mining
A coarse-grained clastic sedimentary rock, composed of rounded to subangular fragments larger than 2 mm in diameter (granules, pebbles, cobbles, boulders) set in a fine-grained matrix of sand or silt, and commonly cemented by calcium carbonate, iron oxide, silica, or hardened clay; the consolidated equivalent of gravel. The rock or mineral fragments may be of varied composition and range widely in size, and are usually rounded and smoothed from transportation by water or from wave action. Compare: breccia.
Industry:Mining
A coarse-grained igneous rock almost entirely composed of andesine. It was named by Turner in 1900. Compare: anorthosite.
Industry:Mining
A coarse-grained metamorphic rock of pelitic composition occurring in the granulite facies. Essential minerals are garnet and biotite, with which occur varying amounts of quartz, K-feldspar, oligoclase, muscovite, cordierite, and sillimanite. The name is from Kinzig, Schwarzwald, Germany.
Industry:Mining
A coarse-grained pegmatite consisting of corundum and margerite with accessory biotite, plagioclase, apatite, tourmaline, garnet, and kyanite. Allied to plumasite grading into normal pegmatite.
Industry:Mining
