I think you mean in situ valuation pepsipet?
Spitfire just up the road claim 1 barrel oil for every 2 tonnes coal. And at todays oil price industry standards dictate $50/barrel margins.
So at 600mt lignite converts to about 300 million barrels Blackham share
So 300m x 50 is $15 Billion nett cash flow isn't it?
Can someone check my maths?