After extensive geological and planning work, Milburn Aggregates were granted resource consent in 1993 and commisioned a new plant to be built 50km south of Auckland at the top of the Bombay Hills. The new plant was fully operational in 1998. Applied Conveyor was not involved in the initial contract for supply of conveyor belt as we did not open our doors until October 1998. We were invited to the site in early 2002 to evaluate some structural changes to the plant. Applied Conveyor had worked with the manager on conveyor issues at previous quarries. Applied Conveyor has a reputation for reliable service and Fenner Dunlop belt has a proven reputation for superior quality. This is supported by other Milburn plants using Fenner Dunlop belt and achieving great results.
The original belt supplied for BC 14 was 1200mm wide 4ply PN150 8×2 ‘N’ of either Korean or Taiwanese manufacturers. The conveyor belt carried – 150mm Basalt Rock – the belt’s life was approximately 12 months. We initially replaced this belt in May 2002 when it had about 2-3 months of life left. The purpose was to put this old belt onto BC39, which was at the end of its life and would need to be changed out as well.BC39 carries 22mm stone and the belt would last another 12-18 months.
Offsetting the purchase of a new belt for BC39 and saved $19,620. The belt has now lasted 43 months. In addition to this, when BC39 requires a new belt a design check has shown the belt spec can change and a further $5000 saving can be made. Meanwhile, we replaced BC14 with a Fenner Dunlop Quarrymaster 2 630/4 8×2. This belt lasted 18 months; the saving by using quality belt is listed below. We installed a second belt on BC14 which also lasted 18 months.
However, because this belt is prone to damage that cannot be completely engineered out, we have trialed a heavier belt that should handle this application and offer even further savings. Not shown in the figures below are benefits of reduced downtime and the savings on the reduced number of repairs to the belt