I choose to believe that Noront found something to justify them making an offer to Probe to exchange and part company.
Second choice is that Cliffs made a suggestion to Probe about making themselves more complete for a buyout.
Distant third is that Noront and Probe guys got together and reached a mutual agreement that each becomes a cleaner company by concentrating on their prime focus.

A very distant fourth is Khareema's 3 guy scenario ( Wishing it was no. 1).

Cheers to all theories and speculations, we are richer from the variety of opinions.