For those interested in round figures and back of the envelope...

For those interested in round figures and back of the envelope calculations

The Chinguetti project from memory was based on an oil price of US$30/barrel.
75000x365x0.19x30 = US$156m/year
A DCF calculation over 9 years at 10% discount pa gives a NPV of US$956.5m at US$30/b.
This must be sufficient to recover capital and operating costs and make a profit, otherwise it would not have gone ahead.

Based on an oil price of US$70/b there is an additional profit of US$40/b.
Assuming the original profit is enough to pay any extra royalties, taxes etc this gives an additional NPV of US$1,274m (A$1,689m) or A$2.58/HDR share for Chinguetti alone.

This does not take into account inflation nor increases in the price of oil. If oil keeps pace with inflation the answer does not change. If oil increases faster than inflation the share value goes up.

Complex