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coal haulage |
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bulk winding |
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Bulk Winding
Bulk winding in a shaft cannot be a continuous process and is unlikely ever to be able to compete with conveyor belts for very high production mines, but if properly designed can achieve adequate rates to suit some mines where a drift is not available for whatever reason. A bulk winding system would normally comprise two counterbalanced shaft haulage vehicles ("skips"), filled from loading pockets in the side of the shaft which dsicharge a measured load of coal from a conveyor feeder system to the skips. Ideally the conveyor feed rate will match the hoisting rate so that the feed can be continuous. Systems are usually fully automatic.
It is possible to design shaft haulage vehicles which can be used for other purposes as well as coal winding but it would not be advisable other than as an emergency egress from the mine.
It is advisable to design an efficient and rapid system of spillage clean-up from the shaft as some spillage is unavoidable.