Keeping Conveyor Belts on Track at a Newcastle Coal Terminal

For dry bulk terminals, delays due to conveyor belt shutdowns can be pretty expensive, not only because of maintenance costs, but also due to demurrage from delays in shipment. (Picture: Flexco)

At the NCIG terminal in Newcastle, Australia, belt tracking issues generally occur because of a lack of friction between the belt and the aluminum idlers. Misalignment sometimes went up to 150 millimetres, triggering the safety switches and causing costly conveyor stoppages.

Conveyor belt tracking problems can occur even on the most modern and sophisticated systems. At the Newcastle Coal Infrastructure Group (NCIG) terminal in Newcastle, NSW, Australia 167 kilometres (100 miles) north of Sydney, belt tracking issues generally occur because of a lack of friction between the belt and the aluminum idlers. Rain only heightens this issue, as the conveyor belts are susceptible to the greater elements.

Construction on NCIG’s coal terminal started in January 2008. Commissioning subsequently started in early 2010, with the first coal export shipped in March 2010. The terminal works as a tolling station, with shipping and other costs borne by the members of the group.

According to Graeme Ralph, senior mechanical engineer at the terminal, the tracking incidents happened early in the operational history of the site. While the causes were not all the same, the common theme was the belt wandering so far from the idler, causing an automatic shut down.

“While we could accept tracking misalignment of up to 40 millimetres (1.5 inch) on each side,” Ralph explains, “going 100 to 150 millimetres (4 to 6 inches) and more was just not acceptable. Especially since safety switches automatically stopped the conveyor system.”

Wide Conveyors, with High Tonnages

This is a coal terminal where the principal conveyor belts are 2.5 metres (98 inches) wide, working with high tonnages, where current capacities can reach up to 33 million tonnes (metric tons) a year. Planned expansion (already approved by the government) is expected to nearly double this capacity to 57 million tonnes. Thus, delays due to conveyor belt shutdowns can be pretty expensive – not only because of maintenance costs, but also due to demurrage from delays in shipment.

There are currently nine main conveyors within the terminal. All major belts are vulcanized, and made to IMAS at1400. The drive pulleys are ceramic and the non-drive pulleys are made of polyurethane. Idlers are made from aluminum and were chosen because of their light weight (approximately 20 kg [44 lb] each). Conveyor lengths range from 75 to 1371 metres (246 to 4494 feet).

Ralph notes that tracking issues varied in the different conveyors and were exacerbated by weather conditions, especially during periods of rain.