- 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 texture of mineral deposits formed by replacement or exsolution, in which the distribution and form of the inclusions are controlled by the crystallography of the host mineral.
Industry:Mining
A texture seen in some schists that results from the intersection of relict bedding planes with well developed cleavage planes.
Industry:Mining
A texture typical of the mineral serpentine in rocks where it replaces a clinopyroxene. Compare: lattice texture
Industry:Mining
A theodolite having particular features of design that make it suitable as an underground surveying instrument; e.g., incorporating an arrangement for the centering movement to be above the foot screws.
Industry:Mining
A theory claiming that the removal of a coal seam caused the overlying strata to fracture at right angles to the inclination of the beds. Subsidence observations do not support this theory.
Industry:Mining
A theory of crushing and grinding; the energy (h) required for crushing varies inversely as the modulus of elasticity (E) and specific gravity (S), and directly as the square of the compressive strength (C) and as the approximate reduction ration (n). The energy in horsepower hours required to crush a short ton of material is given by the following equation, in which all quantities are in feet per second units: h = (0.001748C<sub>2</sub>/ SE) ((n + 2) (n - 1) / n). The theory is due to F. C. Bond and J. T. Wang.
Industry:Mining
A theory of formation of supergene mineral deposits involving the descent from above of mineral-bearing solutions. The theory originated with the Neptunian school of thought of the 18th century, which postulated an aqueous origin for all rocks. Compare: ascension theory
Industry:Mining
A theory of global tectonics in which the lithosphere is divided into a number of plates whose pattern of horizontal movement is that of torsionally rigid bodies that interact with one another at their boundaries, causing seismic and tectonic activity along these boundaries.
Industry:Mining
A theory of hypogene mineral-deposit formation involving mineralizing solutions rising through fissures from magmatic sources in the Earth's interior. Compare: descension theory
Industry:Mining
A theory of hypogene mineral-deposit formation, and the spatial distribution patterns of mineral sequences to be expected from change in a mineral-bearing fluid as it migrates away from a magmatic source. It also deals with thermal-chemical gradients associated with the genesis of ore deposits, whether of direct magmatic origin or not, and with metallogenic zoning on a regional scale.
Industry:Mining
