A 173 ct Type IIa D-colour white gem and a 4 carat pink diamond from Lacapa's September quarter production
ASX-listed Lucapa Diamond’s exploration focus at its Lulo project in Angola aims to locate primary hard rock sources of the large and premium-value alluvial diamonds.

Production from these sources achieved the highest per carat sale prices (US$2 983) in the world in 2016.

Lucapa and its Lulo partners, Empresa Nacional de Diamantes E.P. and Rosas & Petalas, updated the priority kimberlite target list following interpretation of an 8 566 line km Time Domain Electro Magnetic (TDEM) survey flown over the Cacuilo River valley area, where the Lulo alluvial mining operations are focused.

Since then a further 12 kimberlite targets have been drilled, with kimberlite core being extracted from seven of them. Further drilling will be required at two other targets, the core from which is considered inconclusive.

The Lulo kimberlite drilling programme is now currently focusing on the cluster of kimberlite targets located in tributaries draining from the south into the Mining Block 8 area, which has been a regular source of large and premium-value alluvial diamonds.

Significantly, these alluvial diamonds are irregular shaped and jagged-edged, indicating a proximal kimberlite source. This drilling phase will also include a deep hole (200 – 300 m) in the large L259 target, where previous shallow drilling did not intersect visible kimberlite material.

The Lulo partners now have three rigs on site drilling the priority kimberlite targets in a systematic programme.

The progress being achieved to date leaves the Lulo partners on track to complete the drilling of the majority of the updated targets by the end of 2017. The core from this on-going drilling programme will be dispatched to Cape Town for laboratory analysis periodically throughout the programme.

The laboratory analysis process involves crushing the drill core and extracting kimberlite indicator minerals (including garnet, ilmenite, chrome spinel, chrome diopside and zircon) from heavy liquid concentrates.

These indicator minerals are then analysed using an electron microprobe to determine their mineral chemistry. The mineral chemistry results will in turn be used to prioritise likely diamondiferous kimberlite pipes for follow up geological work, including further drilling and bulk sampling to test for diamond content and grade.

Orapa Area F Diamond Project, Botswana

Lucapa’s Orapa Area F diamond exploration project is located within 40 km of the prolific Orapa diamond mine in Botswana. As previously advised, preliminary exploration programmes conducted at Orapa Area F – including ground magnetic, EM and gravity surveys – successfully defined kimberlite drilling targets.

Lucapa is awaiting final environmental approvals to commence a five hole deep core drilling programme at two targets – AN01 and BK38. Drilling is expected to commence next quarter, subject to final approvals.