With all due respect if Xtrata took over FWR then NOT's chromite would essentially be worthless.
As far as NOT's nickel is concerned how could it "cost much more separately" but "they probably would not bother" at the same time.
I think NOT's nickel would be mined but in a divide and conquer strategy there may be some room for a major to get NOT's nickel cheaper by taking out FWR.
I agree with you about "marketability". Nickel et al and chromium are marketed differently and that is important. Cheers.