Ann: December Quarterly Report and Investor Webcasts, page-34

While I don't think mining economy scale is the primary factor in the reported high costs for Core, it could be a secondary factor and potentially significant secondary factor. Being a smaller operation may also contribute to less competitive bidding by contract suppliers and that could have been a factor in appearing to have mining rates >A$5/t. Not having a steady 10+ years open pit work would be another.

Back at the Grants DFS, the life of mine average open pit mining cost was estimated at $10.79 per bcm across Grants/Hang Gong. By the July 2022 ore reserve update that was $13.79 per bcm. SB would have appeared to have agreed a $3/bcm price increase with Lucas. That 28% increase in mining costs makes a difference to the cost of mining. Given mining costs are the largest part of the overall cost it took Core away from the 2021 low cost proposition. It however became GM's problem as by the time there was clarity on cost blowout's, SB was on his way out.



Re equipment
The equipment being used by Core is a robust size (100t haul trucks, up to 200t excavators) but it isn't quite the largest used in any mining project. This could be contributing to a small cost inefficiency. 100t is good sized kit, not the light commercial 10t trucks you might see on suburban roads. It would be interesting to hear what size haul trucks other in production operations use.

Core's fleet is:


Some projects like GL1 intend to use the next size up which may provide minor incremental efficiencies for them. GL1's scoping mining schedule is below.