- 行业: 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 ...
In Pennsylvania, a miner's measurement of length, such as the distance a working face is advanced. With the heel of one foot on a mark, a short step is taken and the tip of the forward toe marks the foot-yard. The next measurement is taken by placing the first foot against the toe of the second and repeating the first step and so on. The foreperson checks measurements with a rule.
Industry:Mining
In petrography, a quantitative method of estimating the volume percentages of the minerals in a rock. Thin sections of a rock are examined with a microscope fitted with a micrometer that is used to measure the linear intercepts of each mineral along a particular set of lines. This method is based on the assumption that the area of a mineral on an exposed surface is proportional to its volume in the rock mass. AGI
Industry:Mining
In petroleum production, commonly thought of as reduced productivity caused by the penetrating, sealing, or plastering effect of a drilling fluid. Actually there is little penetration into the capillaries of an ordinary producing formation, and a slight amount of differential back pressure will remove even thick filter cakes.
Industry:Mining
In petroleum production, one who specializes in drawing subsurface contours in rock formations from the data obtained by a geophysical prospecting party. The draftsman 974 plots maps and diagrams from computations based on recordings of seismograph, gravimeter, magnetometer, and other petroleum prospecting instruments, and from prospecting and surveying field notes.
Industry:Mining
In petrology, a gneiss formed by the metamorphism of a sedimentary rock. Compare: orthogneiss
Industry:Mining
In petrology, one of a system of fissures that radiate irregularly through feldspar and other minerals adjacent to olivine crystals that have been replaced by serpentine. The alteration of olivine to serpentine involves considerable increase in volume, and the stresses so produced are relieved by the fissuring of the surrounding minerals. This phenomenon is common in norite and gabbro.
Industry:Mining
In petrology, the formation of larger crystals from smaller ones by recrystallization.
Industry:Mining
In photographic mapping, either of two rectangular coordinates measured on a photograph with reference to the principal point as origin.
Industry:Mining
In physical chemistry, the transition layer, zone of change, zone of shear, or zeta layer, through which the characteristic qualities of each contacting phase diffuse outward with diminishing strength toward the adjoining phase. Not an interface, since the division is not sharp.
Industry:Mining
In pillar extraction, a method in which lifts are mined in the same way as in the open-end method, except that a fender of coal or a series of small coal stumps is left adjacent to the gob as the lift is advanced. After the lift is completed, the fender or stumps of coal are blasted, and sometimes part of this coal is recovered.
Industry:Mining
