Aim-listed African technology metals miner Andrada Mining has updated the mineral resource estimate (MRE) of its flagship Uis mine, in Namibia, increasing the average lithium grade from 0.63% lithium oxide to 0.73% lithium oxide.

As a result of a 7000 m drilling campaign in 2022 to expand and increase the main V1/V2 pegmatite deposit currently being mined at Uis, the total contained lithium oxide resource also increased by 30% to 587 000 t, with a lithium carbonate equivalent of 1.45-million tonnes.

As such, the total MRE for the V1/V2 deposit, inclusive of mining depletion, has increased from 72-million to 81-million tonnes.

CEO Anthony Viljoen says the enlarged lithium resource at Uis confirms Andrada’s belief that the mine is a globally significant lithium and tin resource that remains open at depth and is one of over 180 mineralised pegmatites within 5 km of the Uis processing facility.

“The drilling programme has exceeded our expectations, delivering higher grades, and has increased the overall tonnage by 13% when compared to the previous resource estimate of 2019, [as well as] 30% more contained lithium,” he says.

The updated resource estimate for the V1/V2 deposit with lithium and tantalum was also upgraded to a measured and indicated classification as a result of infill drilling, increasing by 47% to 38-million tonnes.

Viljoen adds that the updated MRE is solely from the V1/V2 pegmatite, which clearly highlights the significant untapped potential of the wider Uis pegmatite swarm across the licence area.

The average grade of tin at Uis also increased to 0.15% from a previous average of 0.134%, resulting in contained tin metal content of 120 000 t.

With the update, Andrada also declared a maiden rubidium resource with a contained total of 109 400 t at an average grade of 0.14%.

“This MRE has been delivered ahead of our lithium pilot plant commissioning which is due to come online in the second quarter, and is an important step to realise the additional lithium and tantalum revenue streams alongside our tin production,” he says.

This new resource, states Viljoen, will increase the economics for Andrada and will form the basis for the next phase of expansion and growth for the Uis mine.

“The next phase of exploration will investigate the other proximal pegmatites at Uis with the end goal of repeating this process and ultimately expanding the resource at Uis to achieve the exploration target of 200-million tonnes,” he concludes.