Hi, I recall a margin discussion. But you need to discount for risk, time value etc. 10% nominal wouldn't be too far off the mark
So say we had a 3Mtpa operation starting tomorrow with a $15/t margin, lasting for more than 40 years
then a ball park value would be 3*15/10%dr * 70% (tax)
= around $300M before deducting any upfront capex
A take or pay with BHP/RIO for 5 Mtpa would be a nice outcome.