HISTORY OF PGM MINING IN SOUTH AFRICA:
THE CHROME PROBLEM

Melting of platinum group metal (PGM) concentrates in South Africa dates to the 1930s when blast furnaces were installed in Rustenburg to melt concentrate obtained from the  Merensky Reef, one of the two main PGM-bearing reefs in the Bushveld Complex.

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PGM concentrates derived from the Merensky Reef have high concentrations of base metals and sulfur and, more than anything else, it was the high sulfur emissions from the blast furnaces that led to their replacement by rectangular, six-electrode furnaces in the 1960s. At the same time, Pierce-Smith Converters replaced the Great-Falls type converters.

 

Fundamentally the entire PGM process flowsheet development vests in this high-sulfide and base metal content in the feed to facilitate collection of the PGMs in an iron-nickel matte phase. The sulfur emissions and control of sulfur emissions are still the key issues for PGM operations.

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Merensky Reef concentrate decreased in favour of concentrate derived from the UG-2 Reef, the second of the main PGM-bearing reefs in the Bushveld Complex mainly due to the availability of UG-2 relative to Merensky. This however had significant process consequences for the industry over the past 20 years.