RE: iron rich soil I am still here, yes but I really cannot offer any significant contribution at this stage, since I am just like the rest of us fairly in the dark as to what these three figures mean, so there is really not much point here in speculating on it on my part. Seems to me however that the 160 $ /t figure would be (more or less) pure dry magnetite iron ore with nearly 70% Fe. So that would involve major up-grading of the overburden to get from here to pure magnetite iron ore. The 37 $ /t figure I am not sure about at all what that means/represents., but it could involve some up-grading of the raw product.
The 8.75 $/t figure would be as far as I understand just the raw overburden with no further processing involved.
My 2c worth, Wolf E