You could be on the money at $1 billion NPV - that is at current spod pricing but not necessarily using long term pricing assumptions - whatever they may be..
Thinking out loud, for a 10 year operation at 1mtpa, an equation could be:
1mt x US$950/t - op costs A$750/t = A$500m pa GP then divide by 2 for corporate costs, capital cost amortisation and income taxes = A$250m pa net. [Say, A$50m corporate costs, A$150m income tax & A$50m capital cost amortisation].
A$250m pa NPAT x 10 years = A$2.5 billion NPAT over 10 years.
A$500m capital cost Year Zero (consider way too high and probably not even half that - for spod).
10% discount rate applied (including for risk).
This gives a NPV of A$1.036 billion according to my calcs - against A$140m mkt cap.
Opportunity to use as feed for hydroxide at multiple$s.
Surely A$1.00 per share is not out of the question?