- 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 ...
The drilling of holes by hand for site investigations or for the exploration of shallow mineral deposits. The hand drill is used for depths of about 15 m and where the ground is loose or not too hard. Compare: auger
Industry:Mining
The drilling of large-diameter blasting holes in quarries and opencast pits. They are put down vertically from top to bottom of the quarry face. Deck loading is often adopted, 3319 with half to two-thirds of the total charge at the bottom and the remainder in one or more deck charges as required.
Industry:Mining
The drilling of small shafts up to about 5 ft (1.5 m) in diameter with a shot drill. In Virginia, shafts up to 6 ft (1.8 m) in diameter have been sunk by core drilling. A ring 4 in (10 cm) wide is formed by roller bits similar to oilfield rotary drilling. Six tricone cutters are used, and a large core is formed. A central hole is drilled in the core, and a small explosive charge is fired to break it for removal. In some cases, it is removed bodily by a core catcher.
Industry:Mining
The drilling, charging, and firing of a single row of vertical holes along a quarry or opencast face. The holes may be fired simultaneously or by delay detonators to give a peeling action starting at one end of the face.
Industry:Mining
The drilling, charging, and firing of several rows of vertical holes along a quarry or opencast face. The holes may be spaced in the square pattern with delay detonators in the rows as well as row by row. The spacing of the holes will vary according to their depth, diameter, and the type of rock.
Industry:Mining
The driving mechanism of a belt conveyor. It consists of an electric motor or compressed-air turbine connected through a train of reduction gearing to the drum or drums. Motion is imparted to the belt by the frictional grip between it and the drums.
Industry:Mining
The driving of a narrow roadway results in the development of a pressure arch over the excavation. The strata within the arch bend slightly and cease to support the overlying beds, and the load is transferred to the solid or rock along the sides. The wider the roadway, the greater the span of the arch and its height at the crown. A similar but larger pressure arch is formed across a longwall face, with one leg resting on the solid coal and the other on the solid pack behind the coal face.
Industry:Mining
The driving of exploring headings seaward from landside mine workings combined with up-and-down boring to establish higher or lower seams. Also, a technique developed by the National Coal Board, Great Britain, for exploration drilling from a tower that can be floated out to sea and grounded on the seabed.
Industry:Mining
The driving of subsidiary openings designed to prepare blocks of ore for actual extraction by stoping.
Industry:Mining
The driving of the narrow coal headings to form pillars in a pillar method of working.
Industry:Mining
