Ann: West Arunta Project - Luni Assay Results, page-109

60Mt @ 2% seems very likely, at a 50% recovery rate you end up with 600Kt Nb.
To estimate an EV you need to know a likely price, as we move forward I find that difficult to estimate given the uncertainties ahead.

A better way may be to estimate a likely margin of profit per ton Nb produced. I am expecting a plant and production of approx 30Kt per year from the high grade ore giving a mine life of 20 years, with lower grades extending this.

Somewhere between $5,000 - $20,000 per ton is probably likely giving a gross profit of somewhere between $150m - $600m per year.
Not sure how many SOI in 6 years time?
I will let readers determine a likely SP given EPS and PE ratios on the above figures.
Too far away for me with too many unknowns.