OCC’s Final Miner Returns from Overhaul

On 20th May 2026, the last of Oaky Creek Coal’s (OCC) continuous miners – CM27 – came back from overhaul, marking a significant milestone in the history of the mine. To find out more about what the overhaul involved and why this particular one is so noteworthy, Tieri News spoke to Brian Carlton, Engineering Manager at OCC…

Brian, can you give us a bit of background?
Continuous miners are the machines that OCC’s Development team use to mine the roadways underground so we can access the virgin coal. They create the panels for the longwall equipment to be installed at a later date. To put the size of a continuous miner into perspective, imagine a combine harvester used in large-scale farming. A continuous miner is similar in overall size but is far more rugged and substantially heavier, weighing approximately 70 tonnes. Instead of cutting and collecting crops, it is designed to cut through solid coal and rock in an underground mining environment (photos below).

Since Oaky North began operating in 1995, our continuous miners have cut over 500km of underground roadways – that’s almost the distance between Tieri and Townsville! 

CM27 was purchased in 2009 and it’s the last of our continuous miners. It has had a mix of five partial and major overhauls during this 17-year period, with this most recent being the final one…not just for CM27, but for OCC. 

What did the overhaul involve?
Tramming (moving) CM27 around 20km from the underground operation up to the surface. From there, we sent it offsite to the original manufacturer’s (Komatsu) regional overhaul facility, in Rockhampton for extensive repairs. 

How long was the miner out of service?
Approximately six months from start to finish. We had three other miners in service allowing us to send the fourth – CM27 – away for the overhaul without affecting operations.

What work was carried out during the overhaul?
The scope of work included the stripping and inspection of the entire machine, a full re-hose, and the complete overhaul of the electrical package including all motors. All gearboxes were overhauled (cutterhead, traction, conveyor and loading arms), and it was fitted with a fully refurbished and upgraded roof/rib bolter package. 

Lastly, CM27 was repainted in the colour scheme of the Oaky North logo (two tone blue), and the words ‘Final Miner Overhaul 2026’ were engraved on plaques and fitted to celebrate the milestone. 

How does a newly overhauled miner improve reliability?
By resetting the life of major wear components, gearboxes and motors, the miner will suffer fewer breakdowns whilst in service, meaning performance levels and operational time improve.

What does this mean for the crews who operate and maintain the equipment?
Having what is effectively a near-new piece of equipment to mine with is always a bonus to the operators who use them as it contributes to achieving their goal of maximum metres in the shortest space of time.

You mentioned ‘milestone’ before; what makes this particular overhaul so significant for OCC?
CM27 is the final miner at Oaky North to be overhauled, signaling the inevitable completion of mine development as an activity, something that has been a massive part of so many people’s working lives here at OCC and throughout Tieri.

How does this align with OCC’s Life of Mine plan?
Having CM27 overhauled ensures we remain electrically compliant with Queensland legislation, allowing Oaky North to safely and reliably develop roadways for the next two and a half years. 

CM27 is now back in service in MG604, developing the roadways that will provide access to more coal to mine with the longwall. It has already cut approximately 2km to date. It is one of only two miners that will complete development at Oaky North, which is currently planned for mid-2029.