Stellar Diamonds plc has commenced its Phase-2 resource expansion drilling of the 660,000-carat Dyke 1 kimberlite at its Tongo diamond project in eastern Sierra Leone.

Resource Drilling

Previous drilling of Dyke 1 was completed over a 1.9-kilometer section of the 2.5-kilometer-long dyke, to a depth of up to 200 meters from surface. This current 3,000-meter program, being carried out over the current and next month by global driller Boart Longyear, is designed to drill the as yet untested 600-meter strike of Dyke 1 and to extend the inferred resource to a depth of 300 meters from surface. Assuming grade continuity along strike and at depth, which will be modeled by microdiamond analysis, and assuming similar widths to the dyke as already drilled, this would enable the current 660,000 carat resource to potentially be increased to over 1.2 million carats, according to Stellar Diamonds.

"We are firmly focused on significantly expanding the resource at Tongo, which has shown exciting potential to date. This drilling and evaluation programme is designed to double Tongo's existing inferred diamond resource to over 1.2 million carats. The previously announced resource has a grade of 120 [carats per hundred tonnes] cpht and a modelled diamond value of between $225 and $270 per carat, demonstrating the strength on Tongo within the Stellar portfolio," notes Chief Executive Karl Smithson.

Looking Forward

Upon completion of the drilling program, Stellar says it intends to embark upon a pre-feasibility study in order to better define the economics of the resource, prior to the onset of underground trial mining. At current grades and diamond values, Stellar estimates that the in-situ value of the Dyke 1 kimberlite is almost US$300 per tonne.

The AIM-listed diamond development company, which is also advancing the Droujba kimberlite pipe in Guinea, expects the completion of drilling and upgrade of the resource statement during the fourth quarter of this year.