- 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 ...
A rock formed by contact metamorphism of carbonaceous shale, characterized by prominent cleavage or schistosity and the presence of conspicuous chiastolite crystals in a fine-grained groundmass.
Industry:Mining
A rock formed by plant activity or composed chiefly of plant remains. The term was applied by Grabau to a large group including coal, peat, lignites, some types of reef limestones, and oolites.
Industry:Mining
A rock fracturing technique, applied to secondary fragmentation in quarries, that is characterized by an almost instantaneous action and is accompanied by a mechanical weakening of the dielectric and a lowering of the resistance of the puncture path. If, after puncturing, a high-frequency current continues to pass between the contacts, the action 1057 of the conduction current and electric field will rapidly heat the rock, leading to thermal puncture, in which the dielectric is transformed into a good conductor along the puncture path. Further intensive heating will give rise to thermal stresses sufficient to fracture the rock.
Industry:Mining
A rock fragment carried by glacial ice or by floating ice, deposited at some distance from the outcrop from which it was derived, and generally though not necessarily resting on bedrock of different lithology. Size ranges from a pebble to a house-size block.
Industry:Mining
A rock having a fine granular structure, and composed chiefly of feldspar and quartz.
Industry:Mining
A rock mass under stress that ejects small fragments with considerable velocity on breaking.
Industry:Mining
A rock of complex mineralogical composition, formed by contact metamorphism and metasomatism of carbonate rocks. It is typically coarse-grained and rich in garnet, ironrich pyroxene, epidote, wollastonite, and scapolite. Approximate syn: skarn.
Industry:Mining
