@Speaker2me When trying to calculate the potential royalty...

@Speaker2me When trying to calculate the potential royalty revenue keep in mind that the Wonmunna grades are 58% and not 62%. The prices you quote look like 62% iron ore and you will need to apply a discount for the lower grade. This varies but can be substantial

If you used the $/t price for 58% quoted here (http://www.custeel.com/en/csi.jsp) the calculation would look something like this:
5Mtpa x US$75/t * 1% = US$3.75M per annum (=A$5.2M per annum).

It will be interesting to see what MinRes does at lower prices. Do they mine only the reserves (~28Mt) or a much larger slice of the 84Mt resource. Perhaps they might even high-grade the deposit. So many variables!