The challenge
A feeder breaker sits at the start of the coal handling process. Haul trucks tip material into the ROM (run-of-mine), where a large toothed roller breaks oversized coal and rock into smaller material before it moves to downstream conveyors and processing equipment.
It is one of the toughest applications on a mine site. If the feeder breaker stops, the flow of material from the pit can stop with it.
At one Australian coal operation, rising gearbox temperatures and metal detected in oil samples indicated that internal components were wearing. The feeder teeth were also deteriorating, giving the site a clear reason to remove the complete unit during its major annual shutdown.
The shutdown lasted nine days, but removing and reinstalling the feeder breaker each required about two days. That left Motion with roughly five days to dismantle, inspect, repair, and rebuild the gearbox.
Its internal condition would not be fully understood until the unit was opened.
“Until the gearbox was stripped, we only had the temperature and oil sample results to tell us something was wrong,” says Michael Greelish, National Business Development Manager – Fixed Plant Mining & Resources at Motion. “If we had found a cracked gear tooth or damaged shaft, the job could have changed very quickly.”
Any delay could have extended the shutdown and carried a substantial production cost for the customer.
The solution
Motion Engineering & Services in Mackay stripped the gearbox, identified its bearings, seals, and gears, and inspected the internal components.
The team replaced all bearings and seals before crack-testing the gears and shafts to confirm that the retained components were suitable to remain in service through to the next planned shutdown.
Special tooling was also designed and manufactured where standard methods could not release components safely. With limited time available, each unexpected issue had to be resolved without interrupting the rebuild schedule.
The project drew on capability from across the Motion business. Motion Industrial Solutions sourced the bearings, seals, and gearbox oil, while Motion’s Engineering & Services team manufactured new gaskets. The team at Mackay managed the dismantling, inspection, measurements, technical drawings, and final assembly.
“We could do the whole project ourselves without engaging any outside help,” Michael says. “Even drawing up the gears was completed in-house.”
Airfreight and couriers ran throughout the shutdown to keep parts moving. The mine manager and reliability engineer were also present at the Mackay workshop, allowing inspection findings and repair decisions to be discussed as soon as the gearbox was opened.
The strip-down created an opportunity to address a longer-term supply risk. Loose replacement gears were not readily available from the original manufacturer, while sourcing a complete replacement gearbox could involve a lengthy lead time.
Motion therefore documented every bearing and seal and produced detailed drawings of the gears while the unit was accessible. This information can now be used to manufacture a spare gear set and prepare the full component package before the feeder breaker is removed again.
The outcome
The refurbishment was completed within the available shutdown window, allowing the feeder breaker to be reinstalled and returned to service.
The work also gave the mine a clearer plan for the next intervention. Rather than waiting until another shutdown to identify components, Motion can prepare the bearings, seals, and replacement gears in advance.
Further engineering work is now examining how the complete drive arrangement could be made easier to remove and replace.
Motion has taken 3D scans of the shafts to support a possible gearbox redesign. The proposed arrangement would use a split rigid coupling, allowing the gearbox and motor assembly to be released by removing a small number of bolts.
The aim is to reduce a future gearbox changeover from several days to approximately one day, limiting the production exposure if a major failure occurs.
Condition monitoring continues through oil sampling and vibration analysis. Automatic lubricators have also been installed to support consistent lubrication and give the rebuilt equipment the strongest chance of reaching its next planned shutdown.
The project resolved an immediate reliability concern, but its longer-term value lies in what the site now knows. The mine has verified component information, a pathway to stocked spares, and a redesign option intended to make future maintenance faster, more predictable, and less exposed to long equipment lead times.
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