- Industry: 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 ...
Consists essentially of a hollow steel cylinder capped top and bottom by a steel plate. Strain gages are cemented on the inner wall of the cylinder in such a way that, as the cylinder is compressed, the strain gages will be distorted, with a resultant change in 1822 resistance. This instrument is designed for measuring the load transferred from the hanging wall onto props or other units used for support.
Industry:Mining
Consists essentially of a sealed glass tube provided with two electrodes and containing a gas. When an electrical potential difference is applied, a current passes and with a suitable gas, light will be emitted. In the case of mercury vapor, this light is of a bluish color and has proven effective in distinguishing dirt from coal. A special starting electrode close to one of the main electrodes initiates the discharge, and a choke coil in series with the lamp serves to limit the current passing, since the resistance tends to fall with increasing current.
Industry:Mining
Consists essentially of an aneroid barometer and a revolving drum. The movement of the evacuated spring can is transmitted and magnified through a system of levers so that it is finally traced by means of a stylo on the graph paper attached to the revolving drum. The drum is rotated by clockwork, and can be of either the 24-h or the 7-day type. The graph paper is usually marked off in hourly intervals, so that a complete record of the atmospheric pressure at any instant may be obtained. These barographs are used extensively in mining and in meteorological offices.
Industry:Mining
Consists essentially of two heavy metal plattens that are placed one on each side of the previously prepared joint and clamped firmly together. Each platten is heated, and this combined application of heat and pressure over a period completes the joint. These machines are used to vulcanize the belt joints of conveyors.
Industry:Mining
Consists of a cardboard cartridge about 2 in long with a 3/4-in (1.9-cm) outside diameter. The closed end is coated with black powder, and the ends of eight fuses are inserted in the cartridge, in contact with the powder. A master fuse is then inserted, which, when lit, burns to the powder and ignites it. The powder flares brightly and lights the eight fuses.
Industry:Mining
Consists of a continuous wood frame with sheathing planks placed vertically at intervals, usually of about 4 ft (1.2 m), behind it. Used where the banks consist of compacted, stable soils, primarily to prevent initial yield at the top. Compare: close sheathing; tight sheathing.
Industry:Mining
Consists of a driving hub having one or more weighted sections fitted with friction lining on the outer radial surfaces that contact a driven hub having a flange covering that portion of the driving hub containing the radial elements. Upon starting, the radial elements of the driving hub have no appreciable drag, but upon accelerating to the operating speed the force produced by the centrifugal action increases rapidly as the square of the speed and the elements grip the driven element, thereby causing it to speed up to the required speed of the driving hub.
Industry:Mining
Consists of a flexible-type carrying idler mounted in a rigid frame, which fixes the position of the points or roll support.
Industry:Mining
