A comment on the paper ‘A Mintek perspective of the past 25 years in mineral bioleaching’

Abstract

Gericke, Neale and van Staden give an excellent overview of the bioleaching field and how it has evolved. However, they have overlooked a South African development that preceded the 1980 Chilean experience, the earliest engineered bioleaching they record, by more than a decade. In the mid-1960s, the Physical Sciences Laboratory of the Chamber of Mines initiated studies of bioleaching of uranium on slimes dams. Initial laboratory studies1 identified Thiobacillus ferrooxidans and similar related species as being responsible for the rapid oxidation of pyrite, with the formation of ferric iron and sulphuric acid, once the natural pH of the slimes had fallen to below pH5. The mixture of ferric iron and sulphuric acid was known to be a good lixiviant for uranium. This work was reported at a National Institute for Metallurgy symposium, and the National Institute for Metallurgy was, of course, a predecessor of Mintek.