- 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 ...
An epoch of the later Tertiary period, after the Oligocene and before the Pliocene; also, the corresponding worldwide series of rocks. It is considered to be a period when the Tertiary is designated as an era.
Industry:Mining
An epoch of the Quaternary period, from the end of the Pleistocene, approx. 10,000 years ago, to the present time; also, the corresponding series of rocks and deposits. When the Quaternary is designated as an era, the Holocene is considered to be a period.
Industry:Mining
An epoch of the Quaternary period, from the end of the Pleistocene, approx. 10,000 years ago, to the present time; also, the corresponding series of rocks and deposits. When the Quaternary is designated as an era, the Holocene is considered to be a period.
Industry:Mining
An equation for the particle size distribution that can be expected when a material is crushed in a ball mill or rod mill; it is of the form P = 100(x/D)m, where P is the percentage passing a sieve of aperture x, D is the maximum size of particle, and m is a constant which is a measure of dispersion. The equation holds good only if the ratio of size of feed to size of balls is below a critical value.
Industry:Mining
An equation relating to fine grinding: for most powders that have been prepared by grinding, the relationship between R, the residue remaining on any particular sieve, and the grain size in micrometers (x) is exponential: R = 100e<sub>-bxn</sub>, where e is the base of the natural logarithm and b and n are constants. (Dodd, 1964)
Industry:Mining
An equidimensional basin characteristic of cratonic areas, in which the strata dip to a central low point. The term is little used in the United States. Compare: pericline. Ant. quaquaversal.
Industry:Mining
An era of geologic time, from the beginning of the Tertiary period to the present. (Some authors do not include the Quaternary, considering it a separate era.) The Cenozoic is considered to have begun about 65 million years ago. Also spelled: Cainozoic; Kainozoic.
Industry:Mining
An era of geologic time, from the end of the Paleozoic to the beginning of the Cenozoic, or from about 225 million years to about 65 million years ago.
Industry:Mining
