South Africa
Source: geology.com
Source: Geology.com
In
the past, pegmatites were considered the only potential source of
supply of lithium in South Africa. Spodumene, a member of the
pyroxene–group (containing 3.73% Li), was considered the only
potentially exploitable lithium-bearing mineral in South Africa.
In
the Northern Cape and Northern Province, spodumene occurs in zoned
pegmatites. In southern Kwazulu-Natal and in the south-eastern part of
the Vredefort dome, spodumene occurs in unzoned pegmatites.
Northern Cape Province
The Namaqualand Metamorphic belt
hosts various spodumene-bearing pegmatites, which is confined to the
narrow east-west trending “pegmatite belt’ approximately 30km wide and
450km long.
Production
of spodumene from the largest known mineralized pegmatite in
Namaqualand totalled 1000 t. Grades were calculated at approximately 5 t
spodumene per 100 t of pegmatite. (1865 ppm Li)
Lithium
minerals including spodumene, amblygonite, lepidolite, zinnwaldite,
petalite and triphylite-lithiophilite, are found in complex
beryl-bearing pegmatites, concentrated in the western parts of the belt,
north of Steinkopf.
Individual
bodies range from over 2km long and 70m wide to small veinlets, and
consist of coarse-grained quartz and feldspar with muscovite, tourmaline
and garnet. Spodumene has been extracted from pegmatites on the
following properties:
Spodumene Kop 1 and 2
Kokerboomrand 1 and 2
Groenhoekies
Norrabees 1 and 2Noumas
The Noumas Pegmatite was
intermittently worked from 1925 to 1962 for: bismuth minerals, beryl,
tantalum-columbite, muscovite, feldspar and spodumene. The 1 km long by
10 to 42 metres wide pegmatite was emplaced disconcordantly into
foliated granodiorite. Spodumene crystals up to 1 m in length are
characteristic of the 1 to 8 m intermediate zone, and accounts for up to
50% of the mineral assemblage in places.
Kwazulu-Natal Province
Spodumene in significant quantities has been identified in a number of leucocratic pegmatoid bodies on the farm The Corner 11328,
south of Mzube River. The mineralized rocks form part of a suite of
sub-concordant predominantly aplitic sills, which intruded mafic gneiss
of the Mucklebtraes Formation, Margate Terrane. The entire package lies
within a synformally folded klippen structure. The spodumene-bearing
sills, which are the most consistently and well mineralized, are called
the Highbury Pegmatites. The sills are up to 15m thick and were emplaced
at several structural levels along the northern limb of the synform.
The white coarse-grained rocks are composed of quartz, albite,
microcline and spodumene with traces of white lithium mica, garnet,
graphite and rarely beryl. Pale yellowish green to pink spodumene
intergrown with quartz, forms irregular to ovoid poikilocrysts up to
40cm across. This texture is characteristic of spodumene that has
replaced primary petalite. Outcrops with more than 35% intergrown quartz
have been recorded intermittently over a 1km strike length. The
down-dip extent of the mineralized zone cannot be calculated with the
present data and drilling is necessary to establish a reliable resource
estimate. The Li–pegmatites are considered to be late-stage
differentiates of the characteristically anhydrous garnet leucogranites
and charnockites of the Margate Suite, with which they share many
geochemical and mineralogical similarities. The lithium may have been
leached form country rock metasediments during anatexis. A simple
gravimetric test have shown that spodumene can be efficiently
beneficiated to a product of ~7% Li2O with total iron content expressed
as Fe2O3 of ~0.38%
- Pella Resources Ltd has a prospecting license covering the Highbury pegmatites in KwaZulu-Natal and drilling was in progress in 2017.
