A brownfield expansion of the mine was expected to raise its capacity to 330,000 tonnes of copper per year, but BHP said last month an expansion to between 240,000 and 300,000 tonnes per year was more likely because geological conditions had proved less consistent than expected.

Such an expansion is expected to cost up to $US2.5 billion ($3.6 billion), if approved by the BHP board. https://www.afr.com/business/mining/bhp-plots-new-tailings-storage-at-olympic-dam-20190617-p51yin?campaign_code=nocode&eid=socialn%3Atwi-14omn0055-optim-nnn%3Anonpaid-27%2F06%2F2014-social_traffic-all-organicpost-nnn-afr-o&promote_channel=social_twitter