Lepidico holds an 80% interest in the Karibib Project, located within the Karibib Pegmatite Belt in central Namibia in southwestern Africa. The project includes the historical Rubicon and Helikon lepidolite pegmatite deposits.
The Karibib Project holds a JORC Code (2012) compliant global Mineral Resource Estimate (“MRE”) of 11.24 Mt @ 0.43% Li2O (tabulated below).
Measured and Indicated Resources total 8.87 Mt @ 0.43% Li2O, 0.23% Rb, 302 ppm Cs and 2.08% K and will be used to inform an inaugural Ore Reserve estimate for the Phase 1 Project Feasibility Study.
Karibib Project JORC Code (2012) Mineral Resources
Notes: #ASX Announcement dated 30 January 2020: Updated Mineral Resource Estimates for Helikon 1 and Rubicon ^ASX Announcement dated 16 July 2019: Drilling starts at the Karibib Lithium Project
On 30 January 2020, Lepidico announced an updated MRE for the Rubicon and Helikon 1 pegmatites. The MRE was prepared by Snowden Mining Industry Consultants Pty Ltd and is based on 81 drill holes for 5,164 m of additional diamond drilling completed by Lepidico in the second half of 2019. Lepidico initiated a reinterpretation of the mineralisation within the pegmatites into three distinct types: high-grade massive lepidolite zone (Lep Zone), lower-grade disseminated lepidolite zone (Lep Zone B) and a zone dominated by clusters of dark lithium-bearing mica (Mica Zone). All previous drilling was re-logged according to these domains. This has greatly assisted with the understanding of the distribution of the lithium minerals within the pegmatites, and the subsequent interpretation of mineralised domains, which has led to a greater level of confidence in classifying these Resources.
For the first time, this MRE includes grades for the accessory metals caesium (Cs), rubidium (Rb) and potassium (K), which are being evaluated as important by-products in the Feasibility Study.
Importantly almost all of the lithium, caesium and rubidium at Helikon 1 and Rubicon is contained within lepidolite and other lithium minerals (Li-micas and amblygonite) that are amenable to processing using the Company’s proprietary technologies L-Max® and LOH-MaxTM. Only minor lithium concentrations of between 1-3% on average are noted in other mineral species (predominantly petalite), that are not able to be leached by L‑Max®.
Pit optimisations undertaken for Rubicon and Helikon 1 demonstrate these Mineral Resources to be potentially economic at a cut-off grade of 0.15% Li2O.
Modelled Resources at Rubicon (all within Measured and Indicated categories).
Section through Rubicon pegmatite showing optimised pit shell and mineralised domains.
Helikon 1 pegmatite Resource classification.
Section through Helikon 1 pegmatite showing optimised pit shell and mineralised domains.
LOCATION AND GEOLOGY
The project comprises a Mining License (ML 204) of 69 km2 and three Exclusive Prospecting Licences (EPLs 5439, 5555 and 5718) that together cover an area totalling 1,054 km2. Access to the Project is via the national highway from the capital city Windhoek located approximately 180 km to the south east, with the deep-water port of Walvis Bay located 210 km to the south west.
Karibib Project location and infrastructure
The Karibib Pegmatite Belt is located in the southern Central Zone of the NE-trending Damara Belt, a region that holds numerous Li-Be-Ta-Sn and tourmaline-bearing lithium caesium tantalum (LCT-type) pegmatites and U-bearing niobium yttrium fluorine (NYF-type) pegmatitic leucogranites, which have been intruded into the tightly folded supracrustal rocks of the Damara Supergroup.
The large Rubicon and Helikon pegmatites are classic examples of highly fractionated and well zoned LCT-type pegmatites.
Karibib Project tenure and regional geology
At Rubicon a series of stacked sub parallel pegmatites intrude a variable dioritic and pegmatitic granite sequence. The Rubicon pegmatite body forms a prominent ridge approximately 900 m long, striking WNW and dipping to the northeast at around 45° near surface and flattening to about 18°-25° at depth. The Rubicon pegmatite has so far been identified by drilling to over 400 m down dip.
The main Rubicon pegmatite consists of two ellipsoidal well zoned, Li-mineralised bodies developed around two quartz cores and surrounded by a zone of quartz-K-feldspar pegmatite. At Rubicon, the primary lithium minerals present are lithium micas (predominantly lepidolite) and petalite, with minor amblygonite. Historical petalite mining generated large amounts of ‘waste’ dumps slime dumps of lepidolite-rich material.
The historical Helikon occurrences (comprising five main pegmatites known as Helikon 1 – 5) are a series of stacked, sub parallel LCT-type pegmatites that have been intruded into marbles and calc silicates of the Karibib Formation. All five of the pegmatite exposures have in the past been exploited for lithium bearing minerals (lepidolite, petalite and amblygonite), as well as tantalite and beryl. Helikon 1, located 750 m to the south of the Helikon 2 – 5 pegmatites, is the largest exposed pegmatite in the group with a strike length of 350 m, an average thickness of 65m and a dip of 70° to the north. Helikon 1 is truncated at around 60 m depth by a S-dipping low angle fault. The Helikon 2 – 5 pegmatites define a discontinuous strike length of some 1,700 m with variable dips and thicknesses, decreasing in scale westwards.