UK-based Stellar Diamonds has started the front-end engineering and design (FEED) study for the underground mine development of the Tongo-Tonguma project in eastern Sierra Leone.

In connection with the study, a team of consultants is now available on-site to begin various work streams related to the FEED programme.

Through the FEED study, Stellar intends to better define the technical requirements of the project in an effort to ensure that the correct underground mine design is implemented.

In addition, the study will assist the company in properly designing the treatment plant design and layout and clearly identifying the unit processes.

The company has selected Paradigm Project Management (PPM) and SRK Consulting to carry out the study.

Stellar Diamonds chief executive Karl Smithson said: “PPM are highly experienced in the delivery of diamond mine projects and together with SRK they will refine all elements of the mine plan as determined in the published preliminary economic assessment (PEA) to higher levels of confidence in order to reduce the project delivery risk.

“With 66,000m of drilling complete, we will drill of a further 9,000m of mine plan-related drilling to a depth of 75m concurrent with the FEED study.”

“With over 66,000m of drilling completed at the project to date, we will drill of a further 9,000m of mine plan related drilling to a depth of 75m concurrent with the FEED study.”

The aim of additional drilling is to better define the near-surface geology of the kimberlites in the resource.

Drilling is also expected to give access to the geotechnical and hydrogeological information required by the company for the initial years of mining.

Stellar expects the FEED programme to assist in arriving at the final capital expenditure estimate and the operating cost budgets.

According to PPM, the project is estimated to have 3.96 million carats of recoverable resource during the life of mine.