- 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 ...
In reference to experimental-mine tests, the investigation made at a mine when a large sample is taken for testing at the experimental mine; this investigation includes the taking of road dust, rib dust, mine air, and standard coal samples, and the noting of conditions affecting the safety of the mine.
Industry:Mining
In refraction seismic computations, a graph, usually with arrival times of distinctive seismic signals plotted as ordinates and with distances along the surface of the Earth plotted as abscissas. In earthquake studies, the times of arrival of seismic waves at recording stations may be known, but the time of initiation of the waves may be unknown. As data are accumulated from different recording stations, a time-distance graph may be constructed. If it is possible to extrapolate this graph to the origin on the time and distance coordinates, it becomes a travel-time curve.
Industry:Mining
In refraction seismic computations, a plot of the arrival times of refracted events against the shot-point-to-detector distance. The reciprocal slopes of the plotted segments are the refraction velocities for the refracting bed.
Industry:Mining
In refraction seismic work, that distance at which the direct wave in an upper medium is matched in arrival time by that of the refracted wave from the medium below having greater velocity.
Industry:Mining
In refraction shooting, the detecting instruments are laid down at a distance from the shothole that is large compared with the depth of the horizon to be mapped. The seismic waves travel large horizontal distances along distinct interfaces in the Earth, and the time required for travel gives information on the velocity and depth of certain subsurface formations.
Industry:Mining
In refrigeration, an evaporation temperature of 5 degrees F (-15 degrees C), condensing temperature of 86 degrees F (30 degrees C), liquid temperature before the expansion valve of 77 degrees F (25 degrees C), and suction temperature 14 degrees F (-10 degrees C).
Industry:Mining
In regional metamorphism, reduction of the components of a solid rock such as a gneiss to grains. The extreme result of the process is the development of mylonite.
Industry:Mining
In rock crushers, a deliberate weak link that yields if excessive strain is developed. May be a scarfed toggle, weak cap bolts on a pitman, a shearpin in drive, or a clutch designed to fail at a given load.
Industry:Mining
In rock drilling for blasting purposes, injection of water through a hollow drill shank to the bottom of a hole, to allay dust and danger of pneumoconiosis.
Industry:Mining
In rocks, which are composed of many crystals commonly belonging to several mineral species, the term applies to any permanent deformation throughout which the rock maintains essential cohesion and strength regardless of the extent to which local microfracturing and displacement of individual grains may have entered into the process. Compare: plastic deformation
Industry:Mining
