Unlocking PGM mine supply and future production
In South Africa, PGMs occur within a large, layered igneous intrusion called the Bushveld Igneous Complex (BIC) in which more than 70% of the world’s known platinum resources exist. The BIC is a basin-shaped intrusion of some 370 km across, with only its rim exposed. The intrusion contains numerous distinct segregated layers formed during repeated fractionation cycles, three of which contain economic concentrations of PGMs. The main PGM-bearing layers often referred to as ‘reefs’, are called the Merensky Reef, the UG2 Reef and the Platreef.
The UG2 and Merensky Reef
The UG2 Reef is observed on the Western and Eastern Limbs of the BIC and provides over two-thirds of South Africa’s primary platinum supply. The Merensky Reef is also observed on the Western and Eastern Limbs and currently yields around 20% of South African platinum supply. In the early to mid-2000s, UG2 Reef extraction became an important source of primary PGM production with a number of 100% UG2 mine start-ups. Numerous Merensky Reef shafts also now exploit the UG2 Reef. Both reefs contain valuable copper and nickel by-products, but base metal concentrations are lower in the UG2 Reef. The UG2 Reef also contains chromite, which is of a lower grade than the Lower Group (LG) and Middle Group (MG) Reefs, and the additional cost of extracting chrome concentrate through gravity concentrations during PGM processing is minimal, as the majority of necessary infrastructure is already in place and there is only a small additional cost to add the rest of the infrastructure to produce the chrome concentrate.
Chrome concentrate producers are developing relationships with platinum miners to secure UG2 tailings output because primary sources (layers) of production (LG6, MG1 and MG2) are becoming deeper and more expensive to mine.
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