Teck wants to build the mine, or at least design it to their liking. Why else optimze like they have and spend the time on all the infrastructure stuff? The design and optimizations are part of the "sell" to another partner I think. This is probably what they told CUU years ago, which is why the whole Schaft project is under the radar still and took so long. Teck slow played it to try to starve CUU out and get them out of the way earlier for cheaper probably.
I can see Teck bundling Schaft/Galore to an investor. The investor buy-in then pays for the capex of Teck's design for Schaft (also perhaps Galore) and Teck gets to build for free. CUU is not part of this equation and is out of the way as part of the deal announcement with the new partner. The independent PEA by CUU is for the way forward that shows the value of Schaft that can justify the deal to CUU/Teck/partner shareholders.
JMHO
K