Depends on the throughput - to get through 90Mt over say 20...

Depends on the throughput - to get through 90Mt over say 20 years would be 4.5Mtpa and yep that would need BIG dollars.
8Mt over 10 years is a different story - but the economies of scale would be reduced at such low throughput.
Hard to know what the Indonesian "discount" for capex/opex is but I suppose some other examples might be around.
AVB (Brazil) I think had around $50M for a 400ktpa floatation plant, but they are basically a copper mine. This would be a gold mine with copper by product.
Would be nice if AUK can get over 100M at a better grade than they currently have.