The preliminary economic assessment (PEA) of the deposit, undertaken by Paradigm Project Management (PPM), found that there is the potential to yeild stones totalling 955,930 carats, generating $387m over 18 years.

The capital investment needed to get the project up and running is pegged at $24.2m, which will allow the development of both surface and underground mine infrastructure.

Production from the three years surface mining is estimated to yield about 117,800 carats with revenues of around $28.5m, while production from underground mining from years four to 18 is expected to yield 838,124 carats with revenues of $358.2m.

The mine’s economic model was developed using a grade of 120 carats per hundred tonnes and a diamond value of $270 per carat.

The study also unveiled the significant potential to increase mine life and revenues with resource open at depth.

Stellar expects to submit its application for a mining licence in the "near future."

Stellar Diamonds chief executive Karl Smithson said: "The Tongo PEA has delivered robust economics which support the development of an open pit and subsequent underground mine.

"Early cash flow is expected to be generated from the initial surface mining but the mine also represents a long-term and sustainable operation which has the potential to generate solid cash flows from the sale of its very high quality, high grade diamonds over many years.

"Stellar considers that the Tongo mine can be further improved and extended with the development of additional diamond resources from nearby high-grade kimberlites that we have previously identified and tested."