Platinum group element concentrations, mineral chemistry and microtextures of Middle Group chromitite layers at the Thaba Mine, northwestern Bushveld Complex, South Africa

The Bushveld Complex in South Africa is the world’s largest mafic layered intrusion by far and it contains more than three-fourths of the global reserves of platinum group elements (PGE) and more than one-third of global chromium reserves. All of the chromium and much of the platinum are hosted by layers of chromitite in the so-called Critical Zone, a stratigraphic interval of variable thickness (ca 1000 to 1500 m) in the lower third of the 7000-8000 meter-thick intrusion. The data presented herein result from the German-South African project AMREP (Applied Mineralogy for Research Efficiency of Platinum Metals), which investigated the feasibility of extracting PGE from chromitite layers that were mined for chromium at the Thaba Cr mine. The data comprise in-situ mineral analyses by electron microprobe (EPMA data), whole-rock chemical analyses of the platinum-group element concentration (PGE assay data), and microtextural analysis of thin sections to determine the grain size and size distribution of chromite in the layers (CSD data: crystal size distribution).