ASX-listed diamond miner Lucapa Diamond Company has made some significant progress in its search for the hard-rock sources of the high-value alluvial diamonds being mined at the Lulo diamond project in Angola.

Following highly-encouraging tributary sampling results in February 2020, the project Lulo partners commenced a drilling programme in the Canguige catchment area targeting five kimberlite pipes considered prospective to host diamonds, along with two additional priority anomalies.

Once the existing priority kimberlites are drilled, kimberlite bulk samples from these five pipes will be excavated for processing to test for diamonds.

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The Canguige catchment is upstream of the Cacuilo River valley, where Lucapa and its partners have, for several years, been mining some of the world’s highest-value and quality alluvial diamonds.

The five kimberlites and two anomalies in the Canguige catchment became the focus of the search for the primary source of the Lulo alluvial diamonds following the recent recovery of 45 diamonds of up to 3.75 carats from a stream bulk sample taken from the Canguige tributary.

Significantly, the 45 diamonds included a good population of white diamonds – including rare Type IIa gems and top D-colours – and a light fancy yellow. These diamond recoveries confirmed the Canguige catchment area contains at least one diamond-bearing kimberlite pipe contributing to the alluvial diamonds eroded downstream into the Cacuilo River valley.

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Exploration update

The project Lulo partners have finished drilling the first of the five high-priority kimberlite pipes in the Canguige catchment area and are close to completing drilling of the second pipe.

This drilling will determine where best to source the kimberlite material selected for primary source bulk sampling. The drilling is being conducted using the mobile Hanjin rig, which is track-mounted to enable drilling during the Angolan wet season.

Planned exploration timetable

March-April 2020

  • Complete drilling of remaining top-rated kimberlite pipes in the Canguige catchment, weather-permitting. Angled holes will be drilled into each kimberlite to define the size and structure of each pipe and to define near-surface volcaniclastic kimberlite material suitable for bulk sampling;
  • Complete drilling of the two additional priority anomalies in the Canguige catchment highlighted in the technical review to confirm whether they are kimberlite pipes

May-June 2020

  • Commence excavating ~2 500m³ bulk samples of volcaniclastic kimberlite material from each of the five top-rated kimberlites in the Canguige catchment;
  • Truck these bulk samples to the Lulo treatment plant for individual processing to test for diamonds;
  • Conduct more extensive bulk sampling of any kimberlite pipe proven to be diamondiferous to better ascertain diamond grade and quality;
  • Commence stream bulk sampling of other tributaries flowing into the Cacuilo River valley in catchments hosting top-rated kimberlites.

The kimberlites being drilled have already undergone mineral chemistry analysis. If drilling of the new anomalies confirms the targets are kimberlites, they may be sent for mineral chemistry analysis.