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Characteristics and mineralisation of platinum-group elements (PGE) in the upper group 2 chromitite (UG2) and merensky reefs at the Buffelshoek farm , Two rivers platinum mine: implications for platinum-group elements recovery

Thesis (M.Sc. (Geology)) -- University of Limpopo, 2022 / The Two Rivers Platinum Mine (TRP) located in the Eastern Bushveld Igneous
Complex is currently exploiting platinum-group elements (PGE) in the Upper Group
2 chromitite (UG2) Reef at the Dwarsrivier Farm. TRP has acquired a new prospect
(at the Buffelshoek Farm) and is currently planning to mine the UG2 Reef and
potentially also the Merensky Reef (MR). Three drill-cores which intersected the UG2
Reef and MR at the Buffelshoek Farm made available by TRP were sampled for
mineralogical studies using complementary techniques including reflected light
microscopy, mineral liberation analyser and electron microprobe. The platinum
group minerals (PGM) which host the PGE exhibit variability in their flotation rates
and consequently variable PGE recoveries that is mostly attributed to the not so well
understood PGM distributions and characteristics.
The purpose of the study was to investigate the PGE process mineralogical
characteristics such as the PGM phases, their modal abundances and mineral
associations, as well as the grain size distributions within the UG2 Reef and MR at
the Buffelshoek Farm. The observed PGM phases are broadly grouped into PGE
sulphides, PGE arsenides, PGE bismuth-tellurides, PGE antimonides and PGE
alloys. The PGM phases are largely dominated by PGE-sulphides (average of 80%)
in the UG2 Reef and PGE-arsenides (average of 39%) in the MR. Although the UG2
Reef and MR are mineralogically different, the PGM observed are similar in
composition, but vary in their proportions. The PGM are mostly associated with base
metal sulphides typically, pentlandite in the UG2 Reef and silicates, which are
dominated by amphiboles in the MR. The PGM grain sizes generally range between
2 and 22 microns in the UG2 Reef and range between 2 and 32 microns in the MR.

The concentrations of platinum are the highest in both the UG2 Reef and MR, and
with the platinum largely deported in PGE-sulphides (about 69 - 84.9%) in the UG2
Reef and PGE-arsenides in the MR. Palladium is mostly deported in the PGE sulphides (about 52.3 - 69.2%) in the UG2 Reef and mostly deported in PGE
antimonides (about 43%) and PGE bismuth-tellurides (about 37%) in the MR.
Rhodium (Rh) is entirely deported in the PGE sulphides in the UG2 Reef and
deported in PGE sulphides (about 86.5%) and PGE bismuth-tellurides (about 13.5%)
in the MR. Expected recoveries of PGM ranges from 76 to 89% for PGE sulphides
and arsenides in the UG2 Reef and 61.3% in the MR, which is considered good.
PGE bismuth-tellurides, PGE antimonides and PGE alloys are expected to be
variably to poorly recovered, requiring suitable reagents to be well recovered both in
the UG2 Reef and MR. / Faculty of Science and Agriculture Research Division
Geological Society of South Africa
North West University's School of Geo- and Spatial Science

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/3878
Date January 2022
CreatorsPheeha, Lesetja Charles.
ContributorsHammond, N. Q.
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Formatxxii, 140 leaves
RelationPDF

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