- 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 ...
An instrument comprising a small diamond-shaped hammer that falls freely down a graduated tube of glass from a constant height. The hardness of the surface under test is measured by the height of the rebound. In one type of this instrument, the rebound of the hammer actuates the pointer of a scale so that the height of rebound is recorded.
Industry:Mining
An instrument consisting essentially of a plate with a longitudinal slot in the middle, and the means of suspending it vertically. It is used in conjunction with a plumbline for directing the courses of underground drifts, headings, etc.
Industry:Mining
An instrument consisting of a fluorescent screen and a source of ionizing radiation. Used to examine the image formed by opaque objects placed in the beam.
Industry:Mining
An instrument consisting of a series of colored glass beads of different densities contained in a glass tube for testing the specific gravity of electrolytes.
Industry:Mining
An instrument designed for studying harbor surging. A strain gage unit, used in connection with pressure sensitive bellows, comprises the transducer of the pressure head. The four strain gages in the unit are connected to form a bridge circuit that is linked to the recorder by an electrical cable. A direct current voltage is applied to the bridge, and the record is obtained by recording the unbalanced current from a magnetic oscillograph. Any standard strain gage recorder can be used for the recording system.
Industry:Mining
An instrument designed to check ground stability. It amplifies 2.5 million times, and can detect a rock movement as small as 0.000001 in (2.54 mu m). Receiving phones are placed in holes in the area being tested. Either earphones or automatic recording apparatus may be used for listening. A rate of 3 or more microseisms per second indicates probable collapse, and any rate over 25 or 30 per minute is considered dangerous. This instrument is also finding use above ground in checking highway cut slopes.
Industry:Mining
An instrument designed to measure pressure changes within rock as a result of mining operations. The instrument consists of a tongue of steel containing a groove filled with glycerin. When pressure is exerted upon the external surface of the tongue, the glycerin is partially squeezed from the groove and exerts pressure on a diaphram, which accordingly bulges outwards. A strain gage is cemented on the outer wall of the diaphragm, and as the curvature increases and the gage is strained, so does its resistance vary.
Industry:Mining
An instrument designed to provide a continuous vertical profile of ocean currents at a specific location.
Industry:Mining
An instrument designed to take samples of mine gases or water at predetermined times or intervals.
Industry:Mining
An instrument employed for detecting an electric current and showing its direction. It differs from a galvanometer in being only qualitative.
Industry:Mining
