"Need to move fast CF before an increased capex removes all the gains!"

Nah, time is now on CF's side.  LT metal prices are on the rise, inflation is tamed or at least stabilized, and SC capex has steadily gone down every time they check it with a 43-101 report.  

The positive impact on NPV from increases in future LT metal prices (not to mention ten years of optimization not yet applied) will far outstrip the negative from any increases in capex, imo. 

Copper and gold look well set-up to rip higher over the next year or two.  

Now ask yourself; Should Teck make a move on SC before, or after, the next big rip higher in copper and gold prices?

Clearly, its Teck that needs to move fast.