“then why are you here”! The first offer for this transaction goes through Teck, if there is no agreement then CUU has the right to go to the market, providing they don’t sell for a price lower than what Teck had offerred.

What you say is:  "We are agnostic about who we sell our interest to.  We see great value that has yet to be surfaced from the project.  There is a decent chance that Teck refutes the ROFO offer and that gives us only 6 months for reaching out to bidders to convince them to schedule and execute considerable due diligence (to properly see through Teck's decades-thick smokescreen).  With this tight time constraint we would prefer to conduct our auction of the SC interest to already well-informed parties and given the massive opportunity this project presents we thought that you would appreciate the opportunity to get a leg up on due diligence.  To those ends we would like to open a line of communication with you, now."

I don't see the harm. And if they are receptive then that can only help the auction fever. Maybe at the right moment you drop a question about how they prefer to value projects, how they might value SC....
They might reply "Wouldn't you like to know..."  But you have to ask!  You never know.
ABC:  ALWAYS BE CLOSING

Heck maybe there is a 5% chance you wake up a megaladon shark who decides to just gobble-up your entire company faster than you can say ROFO to Teck.