In September 2016, Tawana entered an agreement to acquire mining rights to the giant Uis pegmatite tailings stockpile in Namibia. The project is near the former mining town of Uis, 165km NNE of the coast city of Swakopmund, and 270km NW of the capital Windhoek.
The Uis Project comprises an estimated stockpile of 20Mt of large coarse and fine tailings stockpiles from the Uis tin mine which operated between 1924 and 1990. Unweathered pegmatite material was mined by open cut and hauled to a processing plant for extraction of cassiterite (tin concentrate) by gravity.
Limited sampling to date has indicated potentially attractive lithium grades present.
The most common lithium minerals reported from the unzoned albite-rich Uis pegmatites are:
- Amblygonite (Li,Na)AlPO4(F,OH), contains 7.3-10.0% Li2O;
- Petalite LiAlSi4O10, contains 3.4-4.9% Li2O; and
- Spodumene LiAl (SiO3)2, contains 8% Li2O.
The pegmatites contain significant quantities of tantalum minerals, much of which is believed to remain in the stockpile along with about 30% of the original contained cassiterite.
Metallurgical testwork has commenced (samples have arrived at Nagrom in Perth) and a Resource estimate will be completed by the end of June 2017.
The project was selected on the basis that it comprised an already defined large tonnage of mined and partly processed (fine crushed) unweathered lithium-bearing pegmatite stockpile.
Should drilling and metallurgical test-work confirm an acceptable recoverable grade, Tawana sees the potential for a low capex/opex operation due to:
- No mining required – which normally represents 30-60% of mine operating costs
- No ore haulage required
- No crushing required
- Limited (if any) need for grinding
- Low requirement of electricity and water