I do not think the Can/US $ ratio is in play right now. It may should the deal go through, i.e. once FWR holders end up holding Cliffs shares, but not now.

The recent sp depression of FWR imo is due to a few FWR holders realizing that most if not all value apreciation is already at hand and time to hedge their bets. Some may even sell all their FWR shares to invest in other opportunities that can not be expected to wait for.

Note that there is not much upward potential with CLF even if they aquire FWR due FWR assets being practically dilluted among CLF's vast hold. So with not much upward potential a FWR holder may just as well take the value and thansfer into some higher upward ponential instead of holding FWR and then CLF.
Lastly is the small but real risk of the deal not going through and a FWR holder is left with a quickly depreciating sp, so some hedging is required. Noront and perhaps a few other RofF shares are a good hedge for anyone being nervous about the vote.