- Industry: Mining
- Number of terms: 33118
- Number of blossaries: 0
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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 ...
Differs from straight dynamite in that a portion of the nitroglycerin content is replaced with sufficient ammonium nitrate to maintain the grade strength, manufactured in grade strengths of from 20% to 60%. It is lower in velocity and water resistance than straight 1137 dynamite, but is less sensitive to shock and friction and less flammable.
Industry:Mining
Plows may be divided into two classes: (1) machines that peel the coal to a depth of from 1 to 12 in (2.54 to 30.5 cm) by knives of various designs and the cut coal is then loaded onto a heavy type scraper chain conveyor; and (2) machines that peel a thin slice up to 2 in (5.1 cm) in thickness, by knives attached to each end of a steel box, and the coal is dragged along the face inside the box. From the aspect of speed of travel, plows may be divided into: (1) slow-moving types of 10 to 20 ft/min (3.0 to 6.1 m/min), which remove a thicker slice; and (2) fast-moving types at about 80 ft/min (24.4 m/min), which take a relatively thin slice.
Industry:Mining
Coal size designation, used for anthracite only. Buckwheat is divided into four sizes: No. 1, or buckwheat; No. 2, or rice; No. 3, or barley; No. 4, or barley No. 2 or silt (sometimes also called culm or slush). Buckwheat No. 1 passes through a 1/2-in (12.7- mm) woven wire screen and over a 5/16-in (7.9-mm) woven wire screen, and through a 9/16-in (14.3-mm) round punched plate and over a 3/8-in (9.5-mm) round punched plate. 434 The American Institute of Mechanical Engineers has recommended that buckwheat No. 1 shall pass through 9/16-in holes and over 5/16-in holes, a screen with circular holes being used.
Industry:Mining
In anthracite only, coal small enough to pass through a mesh 3/4 to 1/2 in (1.9 to 1.3 cm) square, but too large to pass through a 3/8-in (9.5-mm) mesh. When buckwheat coal is made, the size marketed as pea is sometimes larger than the above; known also as No. 6 coal.
Industry:Mining
In anthracite only; coal that is small enough to pass through a 3-3/8- to 4-in (8.57- to 10.16-cm) square aperture, but too large to pass through a 2-3/4-in or 2-1/2-in (6.99-cm or 6.35-cm) mesh. Smaller than steamboat, and larger than egg coal.
Industry:Mining
Low-permeability bed, in a stratigraphic sequence, of sufficient permeability to allow movement of contaminants, and to be relevant to regional ground-water flow, but of insufficient permeability for the economic production of water.
Industry:Mining
One system classifies coal by the content of volatile matter: with 10% volatile, anthracite; between 10% and 13% lean coal, semianthracite or dry-steam coal; 14% to 20%, variously designated; 20% to 30%, fat or coking coal. Other systems classify by calorific value, and caking and/or coking property. Post-World War II classifications include (1) volatile matter, (2) caking properties on rapid heating, and (3) coking properties.
Industry:Mining
In foliate metamorphic rocks such as schists and gneisses, large lenticular mineral grains or mineral aggregates having the shape of an eye in cross section, in contrast to the shapes of other minerals in the rock.
Industry:Mining
