I don't think this is correct. Copper Fox makes the offer to Teck, and sets the terms and conditions that they want.
Teck then accepts or refuses it and Copper Fox can offer the same deal (including price and other terms) to someone else, or a better deal, and then Teck is not entitled to stop the sale.
Copper Fox sets the price by getting a third party valuation, and by incorporating the value that they know is there outside of the FS. They have to bear in mind it is pointless to shoot too high because if Teck turns it down they need to attract another buyer.
I have a feeling if Teck turns it down then everyone else will assume it is not such a good deal. In a practical sense it seems more likely to be a negotiated deal that is then put formally into writing.
From the JV: Copper Fox will, prior to selling or disposing of all or any portion of its Interest, first offer to sell the Interest to Teck for cash consideration and upon such other terms and conditions as Copper Fox deems fit.