Nat Gas is normally priced as US$ per Million BTU's
At todays prices = $4.46
Sorry - tried to add to this:
This is equivalent to about A$4.50 per MCFT
So for 12TCF = at $4.50 x 25% x (1/1,000,000) = A$13.5m
Then for 539,913,260 shares currently on offer = A$2.50
THEN - Deduct for Exploration, Production, Sales etc one could allow approx. 30% of total:
i.e. 30% x A$2.50 = 0.75 cents
Thats my guess anyway - any others???