And the other impressive financial metrics highlighted in its prefeasibility study include a post-tax net present value of $2 billion and an internal rate of return of 67%.

Those numbers use a NCM 811 price of $16,397/t, versus a current price of around 19,559/t.

Using the spot price increases the NPV to $3.5 billion and the IRR to 98%.

Feed for the refinery assumes a third party source augmenting production from Blackstone's Ta Khoa mine.

However, the company said it expects exploration success at Ta Khoa will ultimately see sufficient production from the mine to fully feed the refinery.

Blackstone intends to sell down its interest in the refinery to help fund the development, while still retaining a "significant interest".

A development decision in 2022 is targeted.

Meanwhile, a prefeasibility study for the Ta Khoa mine development is next on the cards.

Blackstone reported A$14.3 million cash at the end of the June quarter.

Shares in Blackstone were up 3.3% to 47c in morning trade, capitalising the company at $156 million.