- 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 ...
A method of channeling inclined beds of marble by removing right-angle blocks in succession from the various beds, thus giving the floor a zigzag or sawtooth appearance.
Industry:Mining
A method of checking verticality and/or orientation of a long borehole. A compact camera inserted at a known depth takes a photograph of a magnetic needle and/or a clinometer. Instruments have been developed by Oehman, Owen, and Wright.
Industry:Mining
A method of classifying coals by determining the ratio that exists between the carbon and hydrogen present in them. Thus, if a given coal contains 80% carbon and 5% hydrogen, the C/H ratio would be 80:5, or 16. Bituminous coals have a C/H ratio between 14 and 17, and most anthracites have a ratio between 24 and 29. Abbreviation: C/H ratio.
Industry:Mining
A method of cleaning metal and stone surfaces with sand sprayed over them through a nozzle at high velocity. Sandblasting is also used to form pits on the intrinsically smooth surfaces of materials, such as glass, requiring a particular finish.
Industry:Mining
A method of cleaning raw coal in which the material from 8 to 1/16 in (203 to 1.6 mm) in size is treated in heavy-medium washers, and the fines below 1/16 in are treated by froth flotation.
Industry:Mining
A method of cleaning small sizes of coal, namely, 0.1 to 2 mm, by passing the material over a slowly rotating roller through a high-voltage electrostatic field between the earthed roller and an adjacent wire. Coal loses its charge very slowly and is carried further around by the roller than the impurities, thus effecting separation with reasonable efficiency.
Industry:Mining
A method of collecting particulate particles used chiefly in air polution control that consists of inducing an electric charge on the dust particles and collecting them on an oppositely charged device.
Industry:Mining
A method of comparing the average depth of mine workings. It is based on the average depth from which the output is obtained, weighted for the tonnage produced.
Industry:Mining
A method of connecting together a number of detonators that are to be fired electrically in one blast. Each detonator is connected to the adjacent detonator to form a continuous 2842 circuit having two free ends that are then connected to the firing cable. In British coal mines, all rounds of shots must be connected electrically in series. This results in large rounds having a high electrical resistance, requiring high voltage at the exploder that, in turn, increases the chance of misfires due to current leakage.
Industry:Mining
A method of connecting together a number of detonators that are to be fired electrically in one blast. The electric detonators are connected to two common points. Each detonator offers a path for the electric current, independent of all the other detonators in the circuit, and therefore calls for a higher amperage than a series circuit in which there is but one path.
Industry:Mining
