- Industria: 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 field term for a medium-grained porphyritic igneous rock of felsic but unspecified composition occurring normally as minor stock or dike intrusions, and carrying prominent phenocrysts of quartz. It is a common altered companion to porphyry copper deposits.
Industry:Mining
A field term for a medium-grained porphyritic igneous rock of felsic but unspecified composition occurring normally as minor stock or dike intrusions, and carrying prominent phenocrysts of quartz. It is a common altered companion to porphyry copper deposits.
Industry:Mining
A field term that, in accordance with an arbitrary scale established for use in describing banded coal, denotes a frequency of occurrence of vitrain bands comprising from 13% to 30% of the total coal layer. Compare: sparse vitrain; abundant vitrain; dominant vitrain.
Industry:Mining
A field term that, in accordance with an arbitrary scale established for use in describing banded coal, denotes a vitrain band ranging in thickness from approx. 1/12 to 1/5 in (2 to 5 mm).
Industry:Mining
A field term to denote the degree of luster of attrital coal compared with the brilliant luster of associated vitrain. Compare: dull attritus.
Industry:Mining
A field term to denote, in accordance with an arbitrary scale established for use in describing banded coal, a frequency of occurrence of vitrain bands comprising less than 15% of the total coal layer. Compare: abundant vitrain; dominant vitrain; moderate vitrain.
Industry:Mining
A field term to denote, in accordance with an arbitrary scale established for use in describing banded coal, a frequency of occurrence of vitrain bands comprising more than 60% of the total coal layer. Compare: abundant vitrain; moderate vitrain; sparse vitrain.
Industry:Mining
A fill structure consisting of any material other than coal waste and organic material that is placed in a valley where side slopes of the existing valley measured at the deepest point are greater than 20 degrees , or the average slope of the profile of the valley from the toe of the fill to the top of the fill is greater than 10 degrees .
Industry:Mining
A fill structure consisting of any materials, other than a coal processing waste or organic material, placed in the uppermost reaches of a hollow where side slopes of the existing hollow measured at the steepest point are greater than 20 degrees , or the average slope of the profile of the hollow from the toe of the fill to the top of the fill is greater than 10 degrees . In fills with less than 250,000 yd<sub>3</sub>(191,000 m<sub>3</sub>) of material, associated with steep slope mining, the top surface of the fill will be at the elevation of the coal seam. In all other head-of-hollow fills, the top surface is the fill, which when completed, is at approx. the same elevation as the adjacent ridge line, and no significant area of natural drainage occurs above the fill draining into the fill areas.
Industry:Mining
A filling material composed of clayey rock from which balls are made by a special machine. These balls are driven by an air current through a tube resembling a gun barrel into the excavated area to be filled. By impact and weight, the soft balls are squashed and perfectly fill the excavation.
Industry:Mining
