Nobody knows for sure and I don't think we're likely to find out...

Nobody knows for sure and I don't think we're likely to find out any time soon. I seem to remember hearing somewhere around $70/t full opex cost but I don't recall where that is from.

After they ramp up they will presumably do something similar to what they did when Ferr and Vlak were generating net profit (ie give a gross profit and a much smaller net profit) which with some fancy numberwork from the stated tonnages produced and sold, we may be able to roughly deduce C2 and C3 costs.

But I expect them to be substantial. Washing, royalties, and admin will all play a (fairly small) part but the big killer IMO will be finance costs (since getting into debt is Conti's forte). It wouldn't surprise me in the slightest if Pen barely breaks even at $80/t, and I think we need the RB price to be back towards $110/t before we start making serious money.