See below how Teck structured the purchase for a minority interest in QB.  If I understand properly, they could pay up to 262US for 13% of the project.... so that's equivalent to around 700M CAD for 25% of it.  Best part is that they turned around and sold it for twice the price not too long after.  Teck is willing to pay, but also has tendency to share the risk and defer payments.  It's not out of the question that we could see a similar structure if a sale happens.

IMSA holds 8.5% of the ordinary shares of QBSA and a 5% preferred share interest. The purchase price consists of US$52.5 million paid in cash on closing, an additional payment of US$60 million payable on the issuance of the major approval of the social and environmental impact assessment for the QB2 project and the expiry of certain appeal rights, and a further US$50 million payable within 30 days of the commencement of commercial production at QB2. Additional amounts may become payable to the extent that average copper prices exceed US$3.15 per pound in each of the first three years following the commencement of commercial production, up to a cumulative maximum of US$100 million if commencement of commercial production occurs prior to January 21, 2024, or up to a lesser maximum amount in certain circumstances thereafter. 

MoneyK