- المجال: 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 ...
A method of shaft sinking through loose waterlogged sands that are not suitable for the cementation sinking method. Rings of lined boreholes are put down outside the proposed shaft and in them a very cold solution, such as brine, is circulated until an ice wall has been formed sufficiently thick to enable sinking to proceed normally. The method consists of the following stages: (1) forming a protective wall of ice, with its base in an impervious deposit; (2) maintaining the ice wall until the sinking and lining of the shaft has been completed, and (3) thawing out the ground without damage to the shaft. The freezing method has been revived, largely due to the successful use of bulk concrete, backed by corrugated sheets in place of tubbing, for lining the shaft through the frozen ground. This is followed by wall grouting. Freezing was introduced originally in 1883 by F. H. Poetsch.
Industry:Mining
A method of shaft sinking through loose, watery, or running ground. It consists in lining the shaft with a thick wall, made of brick and cement or brick and hydraulic lime with puddled clay in all cavities. Used for keeping back surface water but the method is now somewhat obsolete.
Industry:Mining
A method of shaft sinking through water-bearing strata by injecting chemicals or liquid cement into the ground. A number of small-diameter boreholes are put down around the shaft--and about 80 ft (24 m) ahead of the shaft bottom#m-through which cement is forced by means of pumps. The cement, when set, seals the fissures and thus prevents water inflows during sinking. The method is most successful in strong fissured strata and least successful in loose alluvial deposits.
Industry:Mining
A method of showing relief on a map by simulating the appearance of sunlight and shadows, assuming an oblique light from the northwest so that slopes facing south and east are shaded (the steeper slopes being darker), thereby giving a three-dimensional impression similar to that of a relief model. The method is widely used on topographic maps in association with contour lines.
Industry:Mining
A method of silling or working out 10 ft (3 m) or so above the haulage level and forming a double-deck gangway. Chutes are constructed at intervals for ore transfer into mine cars.
Industry:Mining
A method of sinking a circular or rectangular shaft through 20 to 30 ft (6.1 to 9.1 m) of sand or mud at the surface. It cannot be used for greater depths as each ring of piles reduces the inside dimensions of the shaft.
Industry:Mining
A method of sinking a deep shaft of large diameter in which a pilot bore of smaller diameter is first cut, after which the cut is enlarged to the final diameter, the debris falling into the pilot bore. When water is encountered, a lining with a moss box at the bottom is forced into place. Compare: Triger process
Industry:Mining
A method of sinking a shaft through loose surface deposits by driving a ring of wood piles down vertically. As the piles are rammed downward, the loose material is removed. Frames are set to prevent the piles being forced inward. Each new set of piles reduces the dimensions of the excavation. To avoid this reduction in size, the piles are driven at an angle away from the shaft space.
Industry:Mining
A method of sinking a shaft through wet clay, sand, or mud down to firm strata. Castiron tubbing, attached ring by ring on the surface, is gradually lowered as the shaft is excavated. There is a special airtight working chamber at the bottom of the lining. A cutting shoe at the lower end of the tubbing helps it to penetrate the soft ground. The caisson method is obsolescent, being replaced by the freezing method, etc.
Industry:Mining
A method of sinking through water-bearing ground in which a shaft is lined with tubbing and provided with an air lock so that work proceeds under air pressure. Compare: Kind- Chaudron process
Industry:Mining
