Once you go out 20 years at a discount rate of 5-8% the NPV gets diluted to nearly nothing. If the annual production rate was higher than say 50,000 tonnes then you may need more resource to fill the 20 year supply chain. Obviously, if a higher price is used and/or a lower cost then more resource becomes economic (not to mention the open at depth idea).

For the NPV to go up substantially the annual production rate would also have to go up. This is a number we do not know. But higher pricing and lower costing would be the two greatest factors in the NPV at this time.

Again, because of this secretive market, we don't know how much we could sell each year and at what price. So the production rate is an estimate.

If this was gold mine, you would simply increase production knowing full well you could sell the product at market prices.