Stellar Diamonds PLC (LON:STEL) has completed the Phase 1 drilling programme on the Droujba kimberlite pipe in Guinea, and called it “a complete success”.
The company said in a statement it has delineated the main pipe at 3 hectares close to surface and the initial microdiamond results have been excellent. The drilling has also discovered two adjacent sub-surface kimberlite intrusions that are associated with geophysical anomalies.
The first phase of drilling, comprising 18 holes for 3,031 metres, was recently completed after which the programme extended into the second, deeper phase of drilling.
These holes were primarily drilled to ascertain geological information of the main Droujba pipe which partly lies beneath a 20 metre deep flooded pit created during previous mining in the 1960s by the Russian Aid Mission.
The kimberlite pipe was intersected in most holes, with the deepest intersection to date being at 222 metres vertical depth from surface.
The surface area of the pipe has been delineated at 3 hectares, which is approximately three times the size previously reported by the Russian Aid Mission.
Two new sub-surface kimberlite intrusions were also intersected to the southeast and west, but adjacent to the main Droujba pipe.
It is not yet known whether these intrusions coalesce with the main pipe at depth but they do form significant additions to the tonnage potential of the resource, the group said.
Further drilling will be aimed at determining the relationship and depth extensions to these new bodies as well as the main pipe as part of the Phase-2 programme. The objective is to delineate the kimberlite resource to a depth of up to 250 metres.
Two samples of kimberlite were recently submitted to the Saskatchewan Research Council laboratory in Canada for microdiamond analysis. These samples comprised 67.60 kiogrammes of kimberlite from the main pipe and 136.55 kilogrammes from the south east sub-surface kimberlite intrusion.
The results from this are expected to be available in the near future.
Chief executive Karl Smithson said: “The preliminary 3D geological model suggests that the kimberlite has significant tonnage potential and our drilling programme over the next few months will entail deeper drilling to more accurately delineate the pipe and its internal geology between 120 and 250 metres depth.
"We expect additional microdiamond results in the near future and will be submitting more material to the laboratory in Canada for further diamond analysis. The microdiamond results received to date are very encouraging. We will shortly be mobilising a processing plant to Droujba and establishing it with a view to bulk sampling of the kimberlite pipe and other proximal kimberlite intrusions."
Stellar owns a 100 percent interest in four high-grade kimberlite projects that are the focus of exploration and development.
In Sierra Leone, at the Tongo project, a bulk sampling programme is ongoing on one key kimberlite to assess the diamond grade and value.
At the Kono underground trial mine, bulk sampling by the company has produced 4,200 carats as part of an economic evaluation exercise.
In Guinea, beside the work at Droujba, bulk sampling is underway on the high grade Bouro kimberlite dyke, which is adjacent to the company's Mandala alluvial diamond operation.