Newfield Resources has announced a positive final investment decision (FID) for its flagship Tongo Diamond Mine development in Sierra Leone, Western Africa.

The company also announced the issuance of $30.5m worth of bonds to commence development at Tongo.

To fund the development of the mine, the company has signed binding agreements to issue two tranches of unlisted, unsecured corporate bonds.

Tranche A, which will raise $20m, can be drawn down on a quarterly basis, with first draw-down expected by the end of September this year. Under Tranche B, A$4.5m ($3.14m) has been received, with residual bonds to be issued on draw-down of the remaining funds over the second half of this year.

Construction on the Tongo mine with underground portal blasting is expected to commence in next few weeks, while the first diamonds are expected within a year of initial portal blast.

Newfield Resources executive director Karl Smithson said: “We are delighted to have agreed a funding package that allows us to commence construction of the company’s flagship Tongo Diamond Mine Development.

“We will now move to commence development activities at Tongo following the positive Final Investment Decision made by the Newfield Board. This will start with completion of the box cut excavation and first blasts for underground portal and decline development.

“Consistent with the recently completed Tongo FEED Study development timeline we expect to be mining first diamonds within 12 months of initial portal blasting.”

Last March, Newfield signed an agreement to acquire the entire issued and to-be-issued share capital of Stellar Diamonds for £7.74m.

Newfield owns gold projects in Western Australia along with Sierra Leone’s advanced diamond project, comprising four exploration licences spread over an area of 780.9km².