- 行业: Mining
- Number of terms: 33118
- Number of blossaries: 0
- 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 ...
Distinctive features of underground surveying are that stations are usually in the roof instead of the floor; the object to be sighted and the crosshairs of the telescope must be illuminated; distances are usually measured on the slope; either the transit tripod has adjustable legs or a trivet is used; and often an auxiliary telescope is attached to the transit, either at one end of the horizontal axis or above the main telescope, with the line of sight of the auxiliary telescope parallel to that of the main telescope. Horizontal and vertical distances are computed from slope distances and vertical angles. The transit is set up at one station, being centered by plumb, and the vertical distance from the station to the horizontal axis of the transit is measured. A plumb bob is hung at the next station, with a point on the plumbline marked by some form of clamping target. The vertical angle to the point so marked is measured, and the distance from horizontal axis to the target is taped.
Industry:Mining
Distributed in an irregular manner, as when ore occurs in bunches or sporadically.
Industry:Mining
Documentation of the existing condition of a structure prior to exposure to blasting vibrations.
Industry:Mining
Dolomite full of worm castings set in a gray matrix and containing chert nodules, near the base of the Upper Cambrian, Scotland.
Industry:Mining
Doorless car of two-way, side-dump design; built in capacities from 4 to 10 yd<sub>3</sub>(3.1 to 7.6 m<sub>3</sub>). The car body is reversible and may be dumped to either side. Dumping is accomplished by means of an external hoist at the dumping point.
Industry:Mining
Downslope movement of part of an earth embankment in blocklike masses without other apparent deformation. Compare: earth slide
Industry:Mining
Downslope movement of part of an earth embankment sufficient to break up blocks and pulverize the material so that it moves in a somewhat fluid manner. Compare: earth slump
Industry:Mining
Drainage that does not reach the ocean by surface streams, such as drainage toward the lowermost or central part of an interior basin. It is common in arid and semiarid regions, as in western Utah.
Industry:Mining
Drainage that occurs as a result of natural oxidation of sulfide minerals contained in rock that is exposed to air and water. It is not confined to mining activities, but can occur wherever sulfide-bearing rock is exposed to air and water. Abbrev. ARD.
Industry:Mining
