If you take out the royalty component and go by the $500 million paid for an approx 8 billion tonne resource what would you get?
$500m/8bt = 6.25 cents p/t?
To me that is really the price Carmichael sold for. The royalties to come are really just an OPEX item. That's the way I see it.
I also note that Waratah Coal (included numerous tenements including 4bt resource) went for around $145m but that was during the GFC.
$145m/4bt = 3.6 cents p/t?