The Uis tin project consists of three project areas in the Erongo region of Namibia, all with historical production. The subject of the project is a pegmatite-hosted tin deposit, one of the largest open castable deposits of its kind.
Uis was discovered in 1911 and was developed by Iscor of South Africa as the largest hard-rock tin mine in the world. Production started in the 1950s and ended in 1990 as a result of depressed tin prices.
The project areas are fully permitted and offer near-term production with low stripping ratios.
Uis has a JORC-compliant resource of 71.54 million tonnes at 0.134% tin, an inferred mineral resource estimate of 71.54 million tonnes and 0.0085% tantalum for 6 091 tonnes contained tantalum and an inferred mineral resource estimate of 71.54 million tonnes at 0.63 % lithium oxide for 450 265 tonnes contained lithium oxide.
Conventional opencast mining methods will be adopted with 10m high mining benches where loading and hauling will be carried out with a fleet of shovels/excavators and dump trucks. Historic excavations display competent pit slope conditions and no groundwater issues.
The initial mining will be focused on exposed ore zones within the old mining footprint as well as virgin pegmatite outcrops to keep waste stripping to a minimum (stripping ratio < 1.0).
Mining material will be liberated using drilling and blasting.
Historical mining footprint only
a fraction of licence area
- Large in-situ (non-JORC) resource remains
- Historical resource of 73 million tonnes at an average grade of 0.136% tin
- Virgin pegmatite outcrops across mining licence area provide huge upside exploration potential
- Ore bodies are up to 40m thick and over 500m along strike
- Existing pits are open-ended at depth and along strike
- Exposed ore zones allow for near-term mining production
- Surrounding pegmatites mapped with confirmed cassiterite mineralisation
- Detailed mapping programme has identified higher grade greisenised areas
- Concurrent exploration will target higher grade pegmatites with low stripping ratios to maintain mining stockpiles
- Advanced process flow design for beneficiation plant
- The plant design is informed by the process flow of the historical Uis mine, known to have been an efficient operation with multiple stages of beneficiation
- AfriTin has opted for Dense Medium Separation (DMS) modules as opposed to the historic jigging circuit
- DMS is regarded as capable of delivering superior separation efficiency
- DMS is one of the simpler gravity processes used for separating minerals of different specific gravities
- DMS combined with a fine gravity concentration circuit will form the backbone of the beneficiation plant
- Wet high intensity magnetic separation (WHIMS) is used to split the final concentrate into a salable tin and tantalum concentrate
Metallurgical test work
- The Uis resource is exceptionally coarse-grained which opens it up to:
- high efficiency processing and
- low comminution costs with a simple process flow
- Heavy liquid separation tests show tin recoveries >74% at concentrate grades of >67% tin
- Other potentially viable metals include tantalum, niobium, lithium, beryllium, feldspar as well as muscovite