- 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 ...
An indurated deposit of volcanic ash dominantly composed of intratelluric crystals and crystal fragments. Compare: tuff; crystal-vitric tuff; lithic tuff; vitric tuff.
Industry:Mining
An indurated deposit of volcanic ash in which the fragments are composed of previously formed rocks; e.g., accidental particles of sedimentary rock, accessory pieces of earlier lavas in the same cone, or small bits of new lava (essential ejecta) that first solidify in the vent and are then blown out. Compare: crystal tuff
Industry:Mining
An indurated pyroclastic deposit composed chiefly of accretionary lapilli or pisolites.
Industry:Mining
An indurated silt having the texture and composition of shale but lacking its fine lamination or fissility; a massive mudstone in which the silt predominates over clay; a nonfissile silt shale. It tends to be flaggy, containing hard, durable, generally thin layers, and often showing various primary current structures.
Industry:Mining
An indurated silt having the texture and composition of shale but lacking its fine lamination or fissility; a massive mudstone in which the silt predominates over clay; a nonfissile silt shale. It tends to be flaggy, containing hard, durable, generally thin layers, and often showing various primary current structures.
Industry:Mining
An indurated soil horizon cemented with calcium carbonate; caliche.
Industry:Mining
An industrial term for a sand or an easily disaggregated sandstone that has a very high percentage of silica (quartz). It is a source of silicon and a raw material of glass and other industrial products. Compare: silica rock
Industry:Mining
An industrial term for certain sandstones and quartzites that contain at least 95% silica (quartz). It is used as a raw material of glass and other products. Compare: silica sand
Industry:Mining
An inert, monatomic, colorless, odorless element, the lightest of the rare gases. Except for hydrogen, helium is the most abundant element found in the universe. The bulk of the world's supply is obtained from wells. Symbol, He. Widely used in cryogenic research; vital in the study of superconductivity. Helium is used for arc welding, as a cooling medium for nuclear reactors, and as a gas for supersonic wind tunnels; extensively used for filling balloons as it is much safer than hydrogen. One of the recent largest uses for helium has been for pressuring liquid fuel rockets.
Industry:Mining
