Commodity: Lithium and Tantalum


Premier African Minerals’ Zulu Lithium and Tantalum Project (“Zulu”) is located 80km from Bulawayo in Zimbabwe. The project is generally regarded as potentially the largest undeveloped lithium bearing pegmatite in Zimbabwe. Zulu comprises 14 mineral claims covering a surface area of 3.5 km2 which are prospective for lithium and tantalum mineralisation.

Resources and Exploration
The Zulu Project has substantial resources. Following a successful 2,500 metres diamond drilling programme between September 2016 and February 2017, Premier published a Maiden SAMREC compliant Inferred Mineral Resource Estimate of 20.1 million tonnes grading 1.06% Li2O and 51 ppm Ta2O5 using a cut-off grade of 0.5% Li2O. The Mineral Resource Estimate contains 526,000 tonnes of Lithium Carbonate Equivalent (“LCE”) and 1,025 tonnes of Tantalum Pentoxide. The Mineral Resource Estimate covers only 35% of Zulu’s known 3.5km surface strike length and the drilling continues to upgrade and expand this Mineral Resource Estimate as the deposit remains open at depth and along strike.

In July 2017, a concerted field reconnaissance programme focused on the eastern part of the 3.5km2 license area at Zulu discovered six new pegmatite zones with true widths of up to 13 metres. Five zones are located up to 500m from the main zone, two of them appear to be trending in east-westerly direction, three others trend NW-SE. The sixth zone seems to be the northern continuation of the main pegmatite zone and is off-set from this by a fault. The discovery was recently made when farmers harvested the land in the eastern part of the license area and this part of the license area with very few outcrops, became accessible. The Company is now looking at further exploration efforts on these new zones to establish the continuation as well depth extensions.    

Metallurgical Testwork
The initial results of the metallurgical testwork programme indicated that a commercial grade, high quality lithium mineral concentrates from both the spodumene and petalite mineralisation at Zulu project can be produced.  The best flotation test work on spodumene pegmatite achieved an overall lithium recovery of 81.8% and a concentrate containing 6.5% Li2O and 0.09% Fe2O3.
The best flotation test work on a mixed pegmatite sample achieved a spodumene concentrate containing 5.9% Li2O being acceptable for spodumene concentrates as feed stock for lithium carbonate production and a commercial grade petalite concentrate containing 3.9% Li2O at exceptionally low Fe2O3 content of <0.01% at an overall recovery in the concentrates of an estimated 70%.  The initial metallurgical testwork was designed for flowsheet development and completed by German-based Dorfner Anzaplan, GmbH, a leading authority in the high purity industrial and strategic minerals and metals businesses. Premier will continue to conduct further testing to optimise the recoveries and grades, as well as improving the flowsheet design for the Zulu project.”

Geological Setting:
The area is underlain by Archaean schists of the Bulawayan System, with serpentinites and banded iron formations at the base in the east and metamorphosed volcanics and sediments as one moves to the west. The schist belt is tear drop shaped measuring 30 km long and 19 km wide near the broad section at the top.  Metamorphism is up to chlorite facies. In the east of the concession epidosites, calc-silicate rocks and gneissic granites prevail. The most northern part of the concession is underlain by a post-Bulawayan massive granite.

In the south, the lithium bearing pegmatites concentrate within an up to 120 metre wide zone between mafic and felsic lithologies. Further to the north, the pegmatites occur mainly in mafic sequences. In the very north of the concession, the pegmatites occur also in granites.

The true widths of the individual pegmatite veins vary from a few centimetres to approximately 5 metres. They commonly occur in groups of several veins; some of the host rocks between the individual pegmatites have undergone intense lithium metasomatism resulting in the formation of a lithium bearing amphibole called holmquistite. Some of the bigger pegmatite veins show a marked zonation with a barren quartz rich core followed by a spodumene rich zone and an outer zone rich in tantalite and albite.

The strike of the individual pegmatites may vary widely but follows more or less N10° in the south and N0° in the north. Some petalite veins in the south follow an E-W direction. The dip of the veins varies as well but the majority of the veins dips with approximately 75° to the west.

Zulu was first pegged in 1955 and intensely explored until the early 1960s. Minor petalite production was reported for 1961 and 1962. The pegmatite bodies intruded along serpentine and sedimentary rocks over a strike length of several kilometers. The width varies between 10 and 25 meters. The bigger pegmatites to the north of the Machakwe River are rich in spodumene and lepidolite, the smaller pegmatites south of the Machakwe River are rich in petalite. The pegmatite bodies strike N20° and dip with 70° to 90° to the west. Parts of the pegmatite are quite rich in tantalite-Mn.

In 1958, O.J. Arnett of Rhodesian Selection Trust (RST) carried out a detailed investigation of the Zulu Project area in order to establish the extent of the lithium mineralization within the pegmatites.

To date, lithium bearing pegmatites (mainly spodumene and lepidolite) have been identified not only at vertical depths of over 200 meters but also along a strike length of some 3,500 meters as well as on the eastern part on the Zulu concession.  Following the Maiden Mineral Resource Estimate, Premier believes that the potential exploration target for Zulu is around the 60-80 million tonnes.