- 업종: 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 ...
A freezing method of shaft sinking, in which a solution of magnesium chloride, MgCl<sub>2</sub>, is circulated through the freezing tubes instead of brine. The magnesium chloride is 1720 cooled to about -30 degrees C at the refrigerating plant, and this temperature is capable of freezing the ground without the solution itself freezing and choking the tubes. Anhydrous ammonia, carbon dioxide, or sulphur dioxide is used as the refrigerating agent.
Industry:Mining
A freight car (as for carrying ballast) that may be unloaded from the side or bottom.
Industry:Mining
A French marble of a beautiful red color and often variegated with small dashes of purple and spots or streaks of white, as in the variety locally known as griotte oeil de perdrix from the French Pyrenees.
Industry:Mining
A frequently used symmetrical steel roof truss that is effective over a maximum span of 50 ft (15.2 m).
Industry:Mining
A friction brake having a metal strap that encircles a wheel or drum and may be drawn tightly against it. A band brake.
Industry:Mining
A friction clutch that protects a mechanism by slipping under excessive load.
Industry:Mining
A friction lock by which a miner may fire the free end of a blasting fuse by a lanyard.
Industry:Mining
A friction-reducing device consisting of hard steel balls in a circular race; also applied to some pieces of equipment, such as a swivel-type double-tube core barrel, in diamond drilling using ball bearings as load-bearing members on rotating parts.
Industry:Mining
