Hi Orlando,
As far as i know...
MGX has a high quality ore on Koolan, however they are mining below sea level and have built a sea wall, so perhaps this is a reason for the high costs.
Irvine Island
I dont beleve the costs per ton to be quite as high as $100/t perhaps around $60 - $70 the ore starts from the surface, as well as the ratio some of the ore is 70% fines and 30% lump and fines you sell at a premium.