Ann: Quarterly Activities Report March 2018, page-17

Feel free to correct my maths if wrong but:
494ppm = 494g/t
Price $110/kg ie $110,000/gram
One tonne of ore at 494ppm fetches USD54.34 = AUD73.43
I don't think the grade is an issue and onsite concentration will impove it substantially.
Size of resource is the question.
Opportunity to approach yet another "offtake partner", Global Advanced Metals (link) , who says
"“Greenbushes is central to our Australian tantalum development strategy as we restore WA’s position as a major supply hub in the global tantalum market,” GAM chief executive Andrew O’Donovan said." (link) (link)