A conveyor network comprising 36 conveyors of various widths, belt speeds and trough angles, feeds into and transfers material away from the plant. COAL, manager of the Wallarah Coal Joint Venture, identified recurring problems at two conveyor transfer points and considered the use of conveyor trough impact frames. However, it decided instead to trial a new belt support system, believing it to be the most cost effective solution mainly due to its simplicity and maintenancefree operation. In one of the transfer locations access points for servicing were limited.
“Most potential solutions we could find included a belt support system but there was no centre idler roller, so these systems worked for about 1.5m before you again needed conventional troughing frames,” said the maintenance/shipping manager at COAL’s Catherine Hill Bay operations office, Bruce Black.
“We required an engineering solution that needed no modification to the existing conveyor idler frames, easily adapted and the fitting requirement had to be one that didn’t require specialists.”
Black said he saw a product display at a mining expo in Sydney by Australian company Kinder & Co and “saw a solution that incorporated slide rails fitting the existing trough roller frames, but retained the original centre roller without changing the belt height and angle so no modification is needed to chutes, skirting height or structure”
“These belt supports can be used over an undefined length because they butt up to one another and still retain the main load centre rollers all the way along without the unnecessary need to fit belt angle trough frames at intervals as with other systems which cause gaps under skirts,” he said.
“Being simple to fit, they do not require boilermakers or fitters to install them and are constructed from materials that are maintenance free for many years. This is opposed to other types of systems which require boiler makers, fitters etc to install or modify existing structures to allow installation.”
One problem area was a dewatering screen on a transfer belt and crusher that handled coal which was dropping from a height of 1.5m at a maximum rate 300 tonnes per hour. With access to the area limited, and in a wet environment, replacing rollers was a concern because it meant increased down time when changing rollers and raised potential occupational health and safety issues. But by installing three belt support systems butted up to one another over a length of 6m, the company expects not to have to change rollers, other than centre rollers, when they fail.
Another problem spot was a transfer site where coal is conveyed at a rate of up to 900tph from one conveyor to another before reaching a trucking road bin. Spillage needs to be contained as it is outside the plant building. Kinder’s solution secured and supported the transfer point, at minimum cost and without significant modifications, with a specially built impact frame.
The supplier replaced existing idlers with low friction slide rails to provide a virtually gap-free underpinning of the moving belt. Made of purposeformulated, ultra-high molecular weight (UHMW) polyethylene, the slide rails are said to reduce component replacement and downtime, mainly due to their low coefficient of friction and resistance to abrasion.
