Overview

Deposit type

• Pegmatite

Summary:

The KLP is located in the southern Central Zone of the northeast-trending Damara Belt, which is a part of the Neoproterozoic Pan-African Damara Orogen. The region hosts numerous late- to post-tectonic (~523–506 Ma) lithium-caesium-tantalum (LCT) type pegmatite deposits and uranium bearing niobium- yttrium-fluorine (NYF) type pegmatitic leucogranites that have been intruded into the tightly folded supracrustal rocks of the Damara Supergroup.

The pegmatites of the Damara Orogen occur in five major belts, including the Karibib Pegmatite Belt, which contains large, zoned lithium-beryllium and gem tourmaline-bearing LCT pegmatites. The Rubicon and Helikon pegmatites are typical examples of highly fractionated, complexly zoned LCT pegmatites.

At Rubicon, a series of stacked sub-parallel pegmatites of variable thickness are intruded into a sequence of diorites and pegmatitic granite. The Rubicon pegmatite is the largest of these and forms a prominent ridge that strikes for a distance of approximately 1,200 m in a west-northwest direction. The pegmatite dips to the northeast, with dips of approximately 45° near surface and flattening to between 18° and 25° at depth. Rubicon is a quartz-feldspar-muscovite pegmatite that is up to 70 m thick and extends down dip for in excess of 400 m. At its thicker portions, the pegmatite is well fractionated and forms ellipsoidal, well zoned, lithium-mineralised bodies developed around central quartz cores. The mineralised zones are 10–30 m thick and extend for most of the length of the pegmatite.

At Rubicon, the lithium mineral is lepidolite with lesser petalite and minor amblygonite. Cookeite occurs as an alteration product of petalite. The petalite, which occurs adjacent to the quartz core, was the focus of historical mining (open pit and underground) and is now essentially depleted. Very little petalite is noted in recent drilling.

The historical Helikon workings expose a series of LCT-type pegmatites (Helikon 1 to 5) that have been intruded along two east-west lines into marbles and calc-silicate schists of the Karibib Formation. Helikon 1, the largest of these five pegmatites, occurs on the southern line. The other four notable pegmatites (Helikon 2 to 5) occur 1 km to the north along a 1.7 km semi-continuous line of pegmatites.

The Helikon group pegmatites have been exploited historically by open pit mining for lithium-bearing minerals (petalite, lepidolite and amblygonite), tantalite and beryl. The Helikon 1 pegmatite has a strike length of 400 m and an average thickness of 65 m, dipping 70° to the north. The pegmatite is strongly fractionated and exhibits distinct mineralogical zonation particularly around a central quartz core that develops in the ticker part of the pegmatite. Helikon 1 is truncated at approximately 60 m depth by a low-angle fault dipping 30° south.

Mineralisation
Mineralogy and internal zonation characteristics at Rubicon and Helikon 1 are similar, aiding the development by Lepidico of a simplified geological code that was used in the most recent phase of drilling to identify lepidolite and lithium-mica mineralisation. For consistency, all of the previous drilling was re-logged according to the revised codes.

Zonation is not perfectly developed in all cases but can be variable, gradational and in some cases absent. In simplified terms, however, a central core of quartz represents the final phase of the fractionated pegmatite melt that crystallised. Immediately adjacent to the quartz core, and usually on the hangingwall side, is a petalite zone. At both Rubicon and Helikon 1, the petalite has essentially been entirely mined out and is rarely intersected by drilling. The lepidolite zone occurs outside the petalite zone or in contact with the quartz core where the petalite zone does not develop. The lepidolite zone can be visually separated into two types, a mauve-coloured “massive” high-grade lepidolite zone (>15–20% fine-grained lepidolite within an albite-quartz matrix) and a paler low-grade “disseminated” lepidolite zone usually less than 10% lepidolite in an albite-rich rock. The most outward zone is a pegmatite phase comprising quartz, albite and a patchwork of clusters of dark mica. This mica zone can also develop independently of the quartz core, either centrally as well as near the margins of the pegmatite, often on the footwall side. The balance of the pegmatite was logged as undifferentiated pegmatite.

Three zones of lithium mineralisation are identified, generally surrounding a central barren quartz core, namely, Lep Z (high-grade “massive” lepidolite), Lep Z B (low-grade disseminated lepidolite dominated by pale albite) and Mica Z (often broad zones of coarse-grained quartz albite pegmatite marked by distinct clusters of dark lithium-bearing mica).

Lep_Z - High-grade lepidolite zone; dark purple, dark grey; generally fine-grained, often cryptocrystalline; lepidolite content noticeable (>15–20%); usually in contact with quartz core.

Lep_Z_B - Low -grade lepidolite zone; pale; white to pale grey; low lepidolite content, but lepidolite noticeable; often displays flow banding; usually occurs below (i.e. footwall to) Lep_Z.

Mica_Z - Mica zone; patchwork rock comprising clusters of dark grey, black, green mica within a pale/white matrix of quartz-feldspar; mica clusters often as radiating concentration of mica, sometimes recognised as dark purple lepidolite; other times black, possibly zinnwaldite; can contain appreciable schorl (black, Fe-rich tourmaline). Occurs in both hanging wall and footwall zones to the Lep_Z; At Helikon, this mica often occurs with pink K-feldspar in footwall (previously often mis-logged as petalite). At both Rubicon and Helikon, the mica zones also occur adjacent to footwall contact where it is associated w ith garnet.

Mining Methods

• Truck & Shovel / Loader

Summary:

The target ore zones are within pegmatite sills formed in granite host rock. The Rubicon orebody dips at 20° to 30° to the north east. The Helikon 1 orebody dips at 50° to 60° to the NNE. Rubicon ore grade zones have true widths of 5 to 15 metres. Helikon 1 ore true widths are 5 to 20 metres. The Rubicon pit will mine the orebody over a strike length of 750 metres and at Helikon 1 ore will be mined over a 360-metre strike length.

The dip, geometry and near surface location of the mineralised zones at the Karibib Project are suitable for conventional open pit truck and shovel operations with drilling and blasting required to fragment both mineralised rock and waste rock. An industry standard approach to mine planning has been undertaken.

Pit wall slopes are based on a geotechnical assessment by Pells Sullivan and Meynink engineers. The geotechnical assessment was based on dedicated geotechnical drilling in final pit walls, mapping of fault structures, core assessment and physical rock testing and failure modelling. Inter ramp angles are 55° based on 15m high benches with 8m berms.

The Rubicon pit design has been completed in four stages and Helikon 1 two stages. The stages have been selected based on value, grade, and strip ratio criteria.

Ore from the pits will be beneficiated by flotation on site to produce a lepidolite concentrate. The concentrate will be transported from Karibib to Lepidico’s proposed Phase 1 Lithium Chemical Plant at in the United Arab Emirates (UAE). The Ore Reserve is based on use of the LOH-Max® process at the chemical plant to produce battery grade lithium hydroxide monohydrate and saleable by-products including amorphous silica and sulphate of potash.

Mining rates are based on the tonnage and grade of concentrate produced by flotation as feed stock for the chemical plant. For the first four years mining focuses on high grade massive and disseminated lepidolite with target concentrate production of 57,671 tpa. Shallow high grade ore tonnes allow this to be achieved at low total mining rates of 600 to 800 ktpa ore and waste. The concentrator feed rate is 333 ktpa.

After Year 4 most of the high grade ore is depleted and the proportion of low grade mica and pegmatite increases. These ore types produce a lower lithium grade concentrate at a lower mass recovery. The chemical plant concentrate target feed rate increases to 66,577 tpa. The concentrator target feed rate to produce this increases to 541 ktpa in Years 5 to 7 then to 650 ktpa from Year 8. Deeper pits and increasing ore tonnes increase the total mining rates to 1.0 to 1.6 Mtpa in Years 5 to 9. When the final Rubicon pit pushback is commenced in Year 10 the mining rate peaks at over 4.3 to 6.6 Mtpa in Year 10 to 12 before gradually reducing from Year 13 to the completion of mining in Year 16.

In addition to the unmined ore tonnes in this ore reserve there are approximately 770 kt in surface stockpiles from former mining and bulk sampling. Sampling indicates that these have recoverable lithium grades sufficient for profitable processing. These are not included in the current Mineral Resource Estimate so cannot be included in the Ore Reserves.

Comminution

Crushers and Mills

Summary:

Stage 2 requires the addition of a second smaller ball mill.

Processing

• Hydrometallurgical plant / circuit
• Crush & Screen plant
• Desliming
• Sulfuric acid (reagent)
• Purification & crystallization
• Flotation
• Concentrate leach
• Dewatering

Summary:

The mineral concentrator will use conventional crushing, grinding, desliming and froth flotation processes followed by dewatering of concentrate and tailings streams. The lithium principally occurs in lepidolite, amblygonite and lithian muscovite although any zinnwaldite will also be recovered through the froth flotation process. The overall recovery of lithium to the lithium concentrate is 75-88% (average 80.1%), at a concentrate grade of 2.5%-3.9% Li2O depending on mineralogy and based on testwork undertaken in 2022.

The concentrator has been designed to process 333,000tpa (dry basis) of ore for the first four years (“Stage 1”) and 541,000tpa (dry basis) from Year 5 of production (“Stage 2”). Stage 2 requires the addition of a second smaller ball mill, reconfiguration of the flotation circuit and the installation of a second tailings filter. The plant will be debottlenecked in Year 7 to cater for a declining head grade. Addition of mill feed from Helikon 4 once Ore Reserve estimates are complete is expected to materially defer the Stage 2 expansion.

The Abu Dhabi chemical plant is designed to process 56,700tpa (dry basis) of lithium mica/amblygonite concentrate at a feed grade of up to 4.2% Li2O for production capacity of 5,600tpa of lithium hydroxide. Lithium hydroxide production will vary according to the grade in concentrate, with an annual life of mine estimate of 2.8% Li2O for average annual production of 4,350t lithium hydroxide. There is considerable excess installed capacity in the impurity removal and lithium refining circuits in the chemical plant, which provides an opportunity for potential debottlenecking and optimisation post ramp-up.

The Ore Reserves are based on production of battery grade lithium hydroxide monohydrate (LiOH.H2O) with by-products of amorphous silica, sulphate of potash (SOP) and rubidium/caesium brine. The general processing path is:
• Beneficiation of the ROM ore by crushing, grinding and flotation in a concentrator at the Karibib mine site. The lepidolite concentrate will grade approximately:
- 1.80% lithium from massive lepidolite;
- 1.36% lithium from disseminated lepidolite;
- 1.17% lithium from the mica/pegmatite ore types.
• The lepidolite concentrate will be transported to a chemical plant to be constructed in the UAE.
• The chemical plant will use Lepidico’s patented L-Max®, LOH-Max® and S-Max® processes to produce battery grade LiOH.H2O with by-products of amorphous silica, sulphate of potash and caesium brine.

The L-Max® process was developed by Lepidico to extract lithium from lepidolite mica concentrates and then purify the leach solution for production of battery grade lithium chemicals. The LOH-Max® process was developed by Lepidico to produce battery grade LiOH.H2O from the purified leach solution. It has never been applied on a commercial scale. The recoveries, consumables and costs in Lepidico’s production and financial models are derived from extensive bench scale testing and continuous pilot plant operation processing. The products from the pilot plant have subsequently been tested to demonstrate by-products at marketable qualities and battery grade lithium chemicals.

Chemicals Conversion
The L-Max® process has been developed over a six year timeframe through an extensive program of laboratory, mini-plant and pilot plant programs. Coupled with extensive flowsheet modelling and vendor testwork, a robust process has evolved that produces lithium hydroxide, high value by-product chemicals of caesium and rubidium (extracted by a separate proprietary process) and a range of bulk by-products, in an efficient low energy approach.

A unique aspect of the L-Max® process is the direct leaching of the lithium bearing mineral from the feed without the need for an energy intensive thermal treatment step preceding the leach, which is employed by many other hard rock lithium conversion processes. The leach conditions are such that very little energy is required to keep the process at temperature. Optimising the leaching conditions has been an important part of the development process.

Handling of the leached slurry is a key part of the L-Max® process and the embedded intellectual property. The slurry is filtered at elevated temperature to yield a solution containing the valuable monovalent metals and a silica-rich filter cake. Effective washing of this cake is required to achieve high lithium recovery to the liquor moving downstream.

The filtered leach liquor, which is rich in aluminium, is cooled resulting in the crystallisation of an alum solid. This alum crystallisation step achieves the separation of lithium from the other monovalent cations. The monovalents, potassium, rubidium and caesium all form alums, whereas lithium does not. Filtering the alum slurry results in the potassium, rubidium and caesium, and most of the aluminium reporting to the solids, and a liquor containing the lithium and small amounts of other impurities. The alum solids are further treated to yield potassium, caesium and rubidium products.

The impure lithium-rich liquor is treated through a series of pH controlled precipitation stages, with limestone and lime, to sequentially remove the remaining impurities, namely iron, aluminium, manganese, and magnesium. The resulting lithium sulphate solution is of sufficient quality to allow the recovery of a high specification lithium product.

Production of lithium hydroxide is achieved without the co-production of sodium sulphate, using the proprietary LOH-Max® process. The unique chemistry of this process has been able to directly produce high purity lithium hydroxide monohydrate in a cost effective manner. The process takes the lithium sulphate liquor produced from the L-Max® process as feed and involves hydrometallurgical reactions to produce lithium hydroxide and a gypsum containing residue.

The chemical plant is designed to process 56,700tpa (dry basis) of lithium mica/amblygonite concentrate at a feed grade of 4.0% Li2O for production capacity of 5,600tpa of lithium hydroxide. The by-products include caesium, rubidium, amorphous silica, SOP, and gypsum residue. The overall lithium recovery to lithium hydroxide is estimated at 90%.

The L-Max®/LOH-Max® processes consist of just five main processing steps for the recovery of lithium hydroxide: feed preparation, leaching, impurity removal, sulphate removal and lithium recovery. A further three processing steps are included for the recovery of SOP, being alum dissolution, aluminium removal and SOP crystallisation. A further three processing steps are included for the recovery of rubidium and caesium products, being rubidium-alum crystallisation and re-pulp, aluminium precipitation and rubidium crystallisation.

Production

Operational metrics

Personnel

Job Title	Name	Phone	Profile	Ref. Date
Consultant - Mining	John Wyche			Dec 19, 2022
Engineering Manager	Ignatius Shaduka	264-81-165-9840		Dec 12, 2023
General Manager Operations	Timo Ipangelwa			Dec 12, 2023
General Manager Sustainability	Benedicta Uris			Dec 12, 2023
GM - Project Development & Strategy	Peter Walker			Dec 12, 2023
Managing Director	Joe Walsh	+1 647-272-5347		Dec 12, 2023
Mine Manager	Malakia Iindombo			Dec 12, 2023
Project Director	Roland Wells			Dec 12, 2023