- Industry: 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 ...
In optical crystallography, those anisotropic crystals having one direction of apparent isotropy, i.e., one optic axis, corresponding to the unique direction of axial symmetry in the hexagonal, trigonal, and tetragonal crystal systems. Uniaxial crystals are positive if their extreme refractive index (extraordinary ray) is less than their axial refractive index (ordinary ray), negative if greater. Compare: isotropic; isotropy; anisotropy; biaxial.
Industry:Mining
In optical microscopy, a condensing lens causes light to converge at a point within a sample to display optical interference patterns or to enhance the Becke line.
Industry:Mining
In optical mineralogy, an anomalous interference color of the first order; e.g., some epidotes.
Industry:Mining
In optical mineralogy, the dispersion that produces an interference figure with color distribution symmetrical to the trace of the axial plane and also to a line normal to it.
Industry:Mining
In optical viewing, the minimum distance possible between two separately distinguishable objects.
Industry:Mining
In optics, elliptically polarized light consisting of upward-spiraling vibration vectors, the surface of which is elliptical rather than circular, as in circular polarization. It is caused by the inconstant lengths of vibration vectors of mutually perpendicular plane-polarized 1077 waves whose path differences differ in phase by amounts other than (n+1)/4lambda on emergence from a crystal.
Industry:Mining
In order to allow for the friction of the skips on the guides and between the air and the skips in the shaft and for other small losses, it is usual to divide the total static torque at any point of the wind by 0.9 for a new shaft with rope guides, or 0.85 for an old shaft with rigid guides. This factor is generally referred to as pit efficiency.
Industry:Mining
In ore beneficiation, smelting, and refining, one who operates a large rotating casting wheel to pour molten, nonferrous metal, such as copper or lead, into molds mounted on the edge of the wheel.
Industry:Mining
In ore dressing, smelting, and refining, a laborer who maintains and repairs the launders (long boxes), used to convey water and mill pulp between the various units of oretreating equipment in a mill.
Industry:Mining
In ore dressing, smelting, and refining, a person who (1) refines lead in a series of oilfired kettles, and (2) removes silver and copper from black mud in a gas-fired kettle, preparatory to the separation of gold.
Industry:Mining
