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Shaft mining or shaft sinking is the action of excavating a mine shaft from the top down, where there is initially no access to the bottom. [1] Shallow shafts , typically sunk for civil engineering projects, differ greatly in execution method from deep shafts, typically sunk for mining projects.
Shaft collars saw few improvements until 1910 through 1911, when William G. Allen and Howard T. Hallowell, Sr, working independently, introduced commercially viable hex socket head set screws, and Hallowell patented a shaft collar with this safety-style set screw. His safety set collar was soon copied by others and became an industry standard.
Sinking a dry shaft means that any water that flows into the excavation is pumped out to leave no significant standing or flowing water in the base of the shaft. When wet sinking a shaft the shaft is allowed to flood and the muck is excavated out of the base of the shaft underwater using a grab on the end of a crane or similar excavation method.
The rate of taper is 1:20 on diameter, in other words 0.600" on diameter per foot, .050" on diameter per inch. Tapers range from a Number 2 to a Number 20. The diameter of the big end in inches is always the taper size divided by 8, the small end is always the taper size divided by 10 and the length is the taper size divided by 2.
The TauTona Mine, formerly Western Deep Levels No.3 Shaft, [1] is a gold mine located in the West Wits gold field west of Johannesburg. The mine is near the town of Carletonville in South Africa . At approximately 3.9 kilometers (2.4 mi) deep, it is home to the world's second deepest mining operation, rivalled only by the Mponeng Gold Mine ...
By June of the same year, the 3.50-meter-diameter main shaft had reached a depth of 180 meters, and the 2.20-meter-diameter relief shaft had reached a depth of 25 meters. [3] On May 9, 1877, the shaft encountered a 1.20-meter-thick layer at a depth of 663 meters, along with two small benches of coal twenty and thirty centimeters thick.
The well is 3.6 meters long and 1.6 meters wide and is equipped with ladders. When abandoned, the well cost 200 francs per meter dug. Sinking resumed in April 1824 and the first layer reached 18.66 meters. The shaft was stopped at a depth of 19 meters and abandoned the same year due to the poor quality of the coal and the influx of water.
Headframe of the #1 Shaft at Oyuu Tolgoi. A steel headframe is less expensive than a concrete headframe; the tallest steel headframe measures 87 m. [4] Steel headframes are more adaptable to modifications (making any construction errors easier to remedy), and are considerably lighter, requiring less substantial foundations.
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