- 行业: Mining
- Number of terms: 33118
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- 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 ratio between the burden of a shothole in tons or cubic yards and the weight of explosive charge in pounds; i.e., tons (cubic yards) per pound of explosive. The factor is dependent on the rock and the fragmentation required, but 5 st/lb (10 t/kg) is about average in quarry blasting.
Industry:Mining
The ratio between the density in a liquid of two minerals that are to be separated (M<sub>h</sub>and M<sub>1</sub>being the heavy and light one, respectively); C = M<sub>h</sub>- 1/M<sub>l</sub>, where water (sp gr, 1) is the liquid. This ratio indicates the grain size above which separation by gravity methods should be commercially practicable. Above 2.5 fine sands (down to below 200 mesh) can be tabled. At 1.75 the lower limit is 100 mesh; at 1.5 about 10 mesh, and at 1.25 only gravel sizes can be treated.
Industry:Mining
The ratio between the index of plasticity and the flow index of a soil.
Industry:Mining
The ratio between the pressure in the mass of a soil and the change of volume caused by such pressure. Compare: Poisson's ratio
Industry:Mining
The ratio between the weight of water and the weight of cement in mortar or concrete. The lower the water-to-cement ratio, the higher will be the strength of the concrete.
Industry:Mining
The ratio obtained by dividing useful power output by power input. This is expressed as a percentage. Fan efficiency is understood to mean that air power is calculated from volume flowing and total pressure, on the assumption that the air does not change in volume. The velocity head, present in the air leaving the evase, is considered as a loss. The power input is that supplied to the fan shaft and thus includes the loss in the fan bearings but excludes all losses in the drive.
Industry:Mining
The ratio of a tensile or compressive stress, triaxial and equal in all directions (e.g., hydrostatic pressure), to the relative change it produces in volume.
Industry:Mining
The ratio of a volume of water that can be drained from a saturated soil under the action of force of gravity to a total volume of voids.
Industry:Mining
The ratio of daughter to parent isotope upon which the age equation is based. For a valid age determination, (1) the isotope system must have remained closed since solidification, metamorphism, or sedimentation, (2) the decay constant must be known, and (3) the sample must be truly representative of the rock from which it is taken.
Industry:Mining
The ratio of face length (X) to length of main haulage roads (L) in the same units; i.e., X/L.
Industry:Mining
