The most important materials handling issue in shaft hoisting systems is how to load the skips._x000D_
During the 20th century, the almost universally accepted method of loading was via a measuring flask. A measured quantity of material was filled into the flask as the conveyance travelled through the shaft and then, when the conveyance arrived at the loading position, it was dumped' into the skip for hoisting._x000D_
Problems associated with flask loading are: high wear in the flask and in the back of the skip, the danger and difficulty of accessing and maintaining the flask, non-standard off-shaft excavations for the loading system, and high dynamic rope loads imposed during loading._x000D_
Direct, high-speed loading of the skip with a premeasured quantity of material on a belt conveyor offers significant advantages over flask loading. These include: standard horizontal excavations for the loading station; maintenance carried out away from the shaft in relative safety; elimination of the flasks and the associated high maintenance wear liners; the ability to control and vary the trajectory of the ore into the skip to minimise skip liner wear; and reduction of dynamic head rope loads by controlling the loading rate._x000D_
Two skip loading conveyor systems have been developed in Australia: BHP Billiton's Cannington Hoisting System, installed in 1996, is believed to be the first conveyor loading system designed for two skips. Two parallel conveyors were installed with a two-way gate controlling feed onto each belt. Cannington was ideally suited to conveyor loading as the very high ore density and relatively low production rate required a relatively small volumetric storage capacity on the weighed belt._x000D_
Newcrest Mining's Telfer Hoisting System, which is to be commissioned in 2005, consists of a single slewing conveyor loading each skip with 32 t of ore. The development of this system eliminates the two-way transfer, improves the accessibility and minimises the excavation required._x000D_
While every hoisting system must be considered on its merits, conveyor loading offers significant advantages to the mining industry in the 21st century.