- 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 ...
The gearing or assemblage of three to four pairs of matched gears in a gear-feed swivel head of a diamond drill by means of which the drill string coupled to the feed screw is made to advance and penetrate the formation.
Industry:Mining
The general arrangement of crystals in an ingot, which consists typically of chill, columnar, and equiaxed crystals. According to the relations between the mass and the temperature of the molten metal and mold, respectively, one or two types of crystals may be absent.
Industry:Mining
The general dimensions (such as average diameter or volume) of the particles in a sediment or rock, or of the grains of a particular mineral that make up a sediment or 2255 rock, based on the premise that the particles are spheres or that the measurements made can be expressed as diameters of equivalent spheres. It is commonly measured by sieving, by calculating settling velocities, or by determining areas of microscopic images.
Industry:Mining
The general disaggregation of rocks; it includes the effects of both the chemical and mechanical agents of weathering with, however, a stress on the chemical effects.
Industry:Mining
The general fan laws are the same for either axial-flow or centrifugal fans. These laws are as follows: (1) air quantity varies directly as fan speed; quantity is independent of air density (twice the volume requires twice the speed); (2) pressures induced vary directly as fan speed squared, and directly as density (twice the volume develops four times the pressure); (3) the fan-power input varies directly as the fan speed cubed and directly as the air density (twice the volume requires eight times the power); and (4) the mechanical efficiency of the fan is independent of the fan speed and density.
Industry:Mining
The general physical appearance or character of a rock, including the geometric aspects of, and the mutual relations among, its component particles or crystals; e.g., the size, shape, and arrangement of the constituent elements of a sedimentary rock, or the crystallinity, granularity, and fabric of the constituent elements of an igneous rock. The term is applied to the smaller (megascopic or microscopic) features as seen on a smooth surface of a homogeneous rock or mineral aggregate. The term structure is generally 3270 used for the larger features of a rock. The two terms should not be used synonymously, although certain textural features may parallel major structural features. Confusion may arise because in some languages, e.g., French, the usage of texture and structure are the reverse of the English usage.
Industry:Mining
The general principle of such meters is to observe a portion of the visual field against its background and then to bring about a condition such that the observed difference in brightness reaches a threshold value so that it is only just discernible. The instruments differ in their means by which this end is achieved. The threshold may be produced quite simply by interposing a light-absorbing medium, such as an optical wedge, in the field 3509 of view. Other methods include reducing the contrast between the object and its background by superimposing a veiling brightness over the observed field.
Industry:Mining
The general term for alloys of aluminum and magnesium used for structural purposes.
Industry:Mining
The generalization, made by Pumpelly in 1894, that the axes and axial surfaces of minor folds of an area are congruent with those of the major fold structures of the same phase of deformation.
Industry:Mining
