- 行业: Mining
- Number of terms: 33118
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- 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 ...
A plume of hydrothermal fluid issuing from the crest of an oceanic ridge; e.g., the East Pacific Rise at the mouth of the Gulf of California. The fluid is clouded by white precipitates, mostly barite and silica. It issues at rates of tens of cm/second and at temperatures of 100 to 350 degrees C (Macdonald et al., 1980). Compare: black smoker
Industry:Mining
A plunger-type jig of either single or mulitple compartments. Its distinguishing features are (1) an automatic control in the form of a cylinder that measures the specific gravity of the mixture of coal and refuse; (2) the refuse draw is a star gate under the overflow lip in each compartment, which extends the full width of the jig; and (3) the hutch is commonly collected with a screw conveyor and discharged through the refuse elevator. Used both for treatment of nut and slack sizes of bituminous coal.
Industry:Mining
A plunger-type jig of relatively simple design with only a single plunger being manually controlled. The hutch compartment is round for good water distribution.
Industry:Mining
A plunger-type jig with the following distinguishing characteristics: (1) the plunger contains check valves that open on the upstroke to reduce suction; (2) the makeup water is introduced with the feed; (3) the screen plate is at two levels, which have different perforations, to keep the water distribution uniform; (4) the bottom of the discharge end of the jig is hinged. This jig has been used extensively in washing anthracite.
Industry:Mining
A plunger-type jig with the plunger beneath the screen. May be either single or multiple compartments. Its distinguishing features are (1) the stroke is produced with a cam operated by a lever and rocker-arm mechanism, (2) the weight of the column of water 1671 above the plunger is balanced by means of compressed air, (3) automatic operation is obtained by means of a submerged float that measures the specific gravity of the mass of coal, refuse, and water at the peak of the pulsion stroke, (4) refuse is withdrawn through a star gate extending the full width of the overflow lip, and (5) the slope of the screen plate is readily adjustable by means of heavy screws at the feed end. It is widely used on bituminous coal on sizes ranging up to a maximum of 6 in (15 cm).
Industry:Mining
A plunger-type jig with the plunger beneath the screen. The distinguishing feature of this jig is the use of two sets of valves beneath the screen plate. Used in washing bituminous coal, both closely sized and slack sizes.
Industry:Mining
A plunger-type jig, usually built with multiple compartments. It has three distinguishing features: (1) plungers on both sides of the screen plate, are accurately synchronized; (2) the refuse is withdrawn through kettle valves near the overflow lips in the respective compartments; and (3) the hutch is commonly discharged periodically by the operator by means of suitable hand valves operated from the working floor. This jig is used extensively on slack sizes of bituminous coal.
Industry:Mining
A plutonic or hypabyssal rock composed chiefly of hauyne and pyroxene, usually titanaugite. Small amounts of feldspathoids and sometimes plagioclase and/or olivine are present. Apatite, sphene, and opaque oxides occur as accessories.
Industry:Mining
A plutonic rock composed almost entirely of plagioclase, usually labradorite. It is a monomineralic equivalent of gabbro but lacks monoclinic pyroxene. Compare: andesinite
Industry:Mining
A plutonic rock composed essentially of alkali feldspar and nepheline. It may contain an alkali ferromagnesian mineral, such as an amphibole (riebeckite, arfvedsonite, barkevikite) or a pyroxene (acmite or acmite-augite); the intrusive equivalent of phonolite. Sodalite, cancrinite, hauyne, and nosean, in addition to apatite, sphene, and opaque oxides, are common accessories. Rare minerals are also frequent accessories.
Industry:Mining
