Oilman
Also have a look at OM Holdings latest 1/4 report. They talk of 3 consecutive price increase since March and BHP price for 46% at close to $6 in May. This would make price of ore worth about $300. A bit higher than what you are using. And looks like increasing. Royalties from Kiwi's numbers are about 1% then so look ok and not too over the top.