Spodumene Concentrate Produced from Lithium Ridge
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Andrada Mining Limited (AIM: ATM), an African technology metals mining company with a portfolio of mining and exploration assets in Namibia, announces that it has produced high-grade lithium spodumene concentrate from mineralised pegmatite material sourced from the Lithium Ridge licence area (ML133).
HIGHLIGHTS
§ High-grade spodumene concentrate, at a grade of 6.8% Li2O (75% spodumene), produced from two Lithium Ridge exploration samples through laboratory-scale flotation.
§ The two samples are composites of drill hole chips, each sourced from a different pegmatite body.
§ The flotation test work achieved a Li2O recovery of 76% (80% spodumene recovery).
§ Further exploration drilling is planned for metallurgical test work and mineralogical characterisation to investigate the extent of spodumene mineralisation in the Lithium Ridge licence area.
Anthony Viljoen (CEO) commented
"These results confirm recoverable spodumene within the pegmatites of the Lithium Ridge licence area. The test work produced battery-grade spodumene concentrate at very attractive lithium recoveries. This follows the conclusion of a first phase of exploration drilling on Lithium Ridge which yielded exceptional results as announced on 6 September 2023. Several notable drilling intersections of up to 2.13% Li₂O were reported, and the drilling demonstrated lithium mineralisation along a 6km strike.
The lithium mineralisation in the pegmatites of Lithium Ridge varies from spodumene-dominant to petalite-dominant. In the area of the licence where the composite samples were sourced, the mineral abundance map (Figure 3) shows a high proportion of spodumene and very little petalite. However, southwest of the licence area, displays a high grade of petalite with minor spodumene mineralisation. The southwest area is the source of ore for the current production of ceramic-grade petalite concentrate for Andrada's lithium pilot plant.
Therefore, based on these results, we will proceed with the next phase of exploration drilling, metallurgical test work and mineralogical characterisation. This will increase geological and metallurgical confidence as well as establish a maiden mineral resource estimate over Lithium Ridge. We are encouraged by the progress towards our strategy of building a large-scale lithium production base."
TEST WORK RESULTS
Metallurgical test work on the two samples selected from exploration drill chips produced during reverse circulation drilling, was conducted by Geolabs Global, a South African provider of mineral processing solutions. The aim of the test was to investigate lithium mineral composition and recovery potential in an area of the Lithium Ridge licence where significant spodumene occurrence was observed during exploration. The samples are composites of drill chips, and each sample was sourced from a different pegmatite body as illustrated on Figure 3 and Figure 5 below. The samples yielded a weighted average feed grade of 1.69% Li2O and 15.2% spodumene as detailed in Table 1.
Table 1: Sources and lithium/spodumene feed grades of the composite samples.
| Sample | Source (Figure 3) | Drill Hole Numbers | Li ₂ O (%) | Spodumene (%) |
|---|---|---|---|---|
| Composite 1 | Pegmatite Body 1 | ATNN23 | 2.03% | 16.2% |
| Composite 2 | Pegmatite Body 2 | ATNN 17, ATNN 18 | 1.38% | 14.2% |
| Average | 1.69% | 15.2% |
The samples were subjected to a standard 5-stage spodumene flotation process to assess the potential recovery steps (Figure 1). Initial de-sliming at 25µm and removal of the mica through flotation were followed by a spodumene rougher flotation stage and three cleaner flotation stages.
Figure 1: Test workflow diagram
The two tests produced a weighted average concentrate grade of 6.8% Li2O or 75% spodumene, at a weighted average recovery by flotation of 76% Li2O or 80% spodumene. The grade-recovery curve for each composite sample is shown in Figure 2.
Figure 2: Li2O grade-recovery curves for each composite sample.
The full assay results are tabulated below, confirming the potential for the production of a battery-grade spodumene concentrate.
Table 2: Assays from final flotation concentrate products.
| Sample | Li ₂ O (%) | SiO ₂ (%) | Al ₂ O ₃ (%) | Fe ₂ O ₃ (%) | TiO ₂ (%) | CaO (%) | MgO (%) | K ₂ O (%) | MnO (%) | P ₂ O ₅ (%) |
|---|---|---|---|---|---|---|---|---|---|---|
| Composite 1 | 7.00 | 50.48 | 26.52 | 1.00 | 0.08 | 0.25 | 0.2 | 0.27 | 0.14 | 3.77 |
| Composite 2 | 6.62 | 53.36 | 25.4 | 1.83 | 0.04 | 0.34 | 0.08 | 0.42 | 0.354 | 2.813 |
| Weighted Average | 6.84 | 51.66 | 26.06 | 1.34 | 0.06 | 0.29 | 0.15 | 0.33 | 0.23 | 3.38 |
Figure 3 below shows the mineral abundance in the feed and final concentrate of each composite sample, demonstrating the potential to upgrade the spodumene in the feed to a high-grade concentrate. The Composite 2 sample recorded a spodumene grade of 80%.
Figure 3: Mineral abundance in the feed and final concentrate of the composite samples.
The Company believes the spodumene mineralisation could also be amenable to dense medium separation ("DMS"). The fine particle size distribution of the drill chip samples made it unsuitable for DMS test work, but future sampling and test work will cater for DMS testing.
LITHIUM RIDGE
Lithium Ridge (ML133) is a fully permitted mining licence located approximately 35 km southeast of the town of Uis and Andrada's operating Uis Mine. The Company completed an initial exploration drilling programme on Lithium Ridge in Q3 2023 (see announcement dated 6 September 2023). A second phase of drilling, including mineralogical characterisation, is planned for Q1 2024 to increase geological confidence, prove continuity of mineralisation along strike, and to establish a maiden mineral resource estimate. In addition, the Company plans to conduct comprehensive metallurgical test work to support future feasibility studies for a mining and processing facility at Lithium Ridge.
Figure 4: Andrada's mineral licenses in the Erongo Region of Namibia. ML134 ("Uis"), ML133 ("Lithium Ridge") and ML129 ("Spodumene Hill") all occur within a 40 km radius of the town of Uis.
Figure 5: Map displaying the localities of the drill holes and the mapped surface exposure of pegmatites in the area from which the composite samples were taken. Composite 1 was sourced from hole ATNN23 and Composite 2 was sourced from ATNN17 and ATNN18. Line A-A' indicates the position of the cross section shown in Figure 6 below.
* The composite samples do not represent the full pegmatite intersections of the holes but were taken from selected sub-samples within the full intersections.
Figure 6: Section line A-A' displaying a projection of the reported drill hole for which the results are reported in this announcement. Since there is only a single intersection of pegmatite, the morphology of the unit was inferred from mapped surface expressions. All holes were drilled at an inclination of 60° from the horizontal.
COMPETENT PERSON
The technical data in this announcement has been reviewed by Laurence Robb, a Non-Executive Director of Andrada. Laurence Robb (BSc Hons, MSc, PhD, FGS, FGSSA, FRSSA) has more than 40 years of industry-related geological experience. He is registered as a Professional Natural Scientist with The South African Council for Natural Scientific Professions and is a Chartered Geologist with the Geological Society of London. He was Professor of Economic Geology and Director of the Economic Geology Research Institute at the University of the Witwatersrand's School of Geosciences. He is currently based at Oxford University as a Visiting Professor. He has reviewed the technical disclosures in this release and consents to the release of the information contained herein.
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