Fe2O3, is iron ore, 69.96 is the highest Fe that can be achieved. The 69.96 is multiplied by 1.4397 to give the result of approx 100.00. Any grade under the 69.96 does have impuruties in it. TTY would be silly to not blend their ore down to something similar to what other exporters are selling, their deposit will last longer.
I hope my sums are correct