Ann: Half Yearly Report and Accounts, page-7

"Havilah engaged Deutsche Bank to seek parties who could replace BHP under similar terms to that originally agreed with OZ Minerals. At the end of the period Havilah was engaged with several interested parties, but the ultimate outcome of these discussions is as yet undetermined."

The Kalkaroo option was negotiated at a time when Copper was trading at $6797 AUD per ton it is now $14800 per ton.
Gold was trading at $1727 AUD per oz it is now $3713
The Kalkaroo option was priced at $205m plus a $135m contingency arrangement should the copper price exceed $10,000 USD per ton, it seems that a copper price above $10,000 per ton is only weeks away.
Should a similar deal be struck to sell Kalkaroo it is probable that a price of $340m will be achieved at an absolute minimum for Kalkaroo alone.

I think a deal could drop at any moment given that AUD Copper and Gold prices have doubled over this time frame and copper is at the start of its anticipated bull run heading towards 2030>.