Aim-listed Andrada Mining’s updated mineral resources estimate (MRE) for the V1V2 pegmatite at the Uis tin mine, in Namibia, shows increases in average lithium grade and volumes of the measured and indicated resource classifications.

The MRE reveals the average lithium grade increased to 0.79% lithium oxide (Li₂O) from the 0.73% Li₂O declared in 2023.

The company notes contained Li₂O increased from 587 000 t to 610 000 t, while the measured resource tonnage increased by 30% to about 27.3-million tonnes, and the indicated resource tonnage increased by 2% to about 17.5-million tonnes.

The MRE total tonnage decreased from 81-million tonnes in 2023 to 77.5-million tonnes owing to depletion from ongoing mining.

CEO Anthony Viljoen says this updated MRE is another positive step toward the company’s goal of being a “premiere” African producer of tin, lithium and tantalum.

“Our exploration team has once again demonstrated that the V1V2 pegmatite has significant lithium potential, shown by increases in both the average lithium grade and contained metal tonnage.

“Critically, this updated resource also allows us to better quantify the potential lithium concentrate credits we can generate alongside our tin production, optimising the overall project economics. Furthermore, the updated MRE further enhances the project economics of the Uis mine operations and will enable the determination of a lithium mineral reserve,” he says.

Andrada says the MRE has been informed by 145 historical ISCOR drillholes comprising eight diamond drillholes and 137 reverse circulation (RC) drillholes, together with 77 validation drill holes, comprising 48 diamond drillholes and 29 RC drillholes drilled by Andrada between 2018 and 2023.

The Andrada drillholes were completed on a nominal grid spacing of 60 m by 60 m, with wider spacing of up to 80 m by 200 m for the deeper portions.

Most holes were drilled at a vertical orientation, but selected shallower holes were inclined at angles up to -70° southeast, to obtain intersections more perpendicular to the dipping pegmatite.

The company notes that the 2023 MRE update was determined from geological information of all holes above, except for 16 holes whose data were not available at the date of publication.

The current MRE update includes analytical data from the final 16 drillholes obtained subsequent to the previously published MREs.

Andrada notes that the updated V1V2 MRE is reported in accordance with the Joint Ore Reserve Committee (Jorc) Code and identifies 77.51-million tonnes of mineralised pegmatite with an average grade of 0.79 % Li₂O, 0.15% tin and 82 parts per million (ppm) tantalum.

This MRE includes 27.33-million tonnes at an average grade of 0.82 % Li₂O, 0.15% tin and 90 ppm tantalum for the near-surface measured category, 17.50-million tonnes at an average grade of 0.79 % Li₂O, 0.15% tin and 86 ppm tantalum for the indicated category, and 32.68-million tonnes with an average grade of 0.76% Li₂O, 0.16% tin and 73 ppm tantalum for the inferred category.

The contained lithium is also stated in terms of lithium carbonate equivalent, being the metal converted to lithium carbonate by a factor of 5.323.

Andrada says the MRE is reported within a conceptual pit shell to demonstrate reasonable prospects for eventual economic extraction (RPEEE) and incorporates the sale of petalite and cassiterite.

Rubidium (in mica), tantalite and niobium associated with tantalum in the columbite group minerals concentrations and tonnages were also estimated but have not been included in the RPEEE considerations.

The company explains that an attributed-basis tabulation of resources, as presented in previous estimates, is no longer applicable because the V1V2 pegmatite is within the Uis mining licence 134 now wholly owned by Andrada Mining and its subsidiaries.

“This MRE update provides an increase of the lithium grade and tonnage in the measured and indicated classification. These results further outline the polymetallic potential of the V1V2 pegmatite,” the company says.

The surface information used for the basis of this MRE was acquired at the end of August 2024, and the volumes mined since the previous MRE have been accounted for, resulting in a reduced overall tonnage.