The heterogenite (CoOOH) is the most abundant product arising from oxidation of sulfides of cobalt primary Katanga copper Arc. This recent episode of oxidation (Pliocene) permitted the concentration of heterogenite in the upper reservoir by selective leaching of copper and cobalt to form a cap. These cobalt caps were partially dismantled during the Quaternary, during the landscape erosion, heterogenite then being re-filed in the valley bottoms.
The heterogenite (deposit in the form of "veneer" of valleys or as a constituent of soil [ "black earth"]), its crumbly and earthy character and its exceptional levels of Co are most actively exploited by artisanal miners ( "diggers") in Katanga.
satellite view of the Tshamilemba district in Lubumbashi next to a metal processing plant. Wikimapia (accessed April 16,2009)
However, the trace elements intimately associated with heterogenite (U, As, Mo, Ni) are harmful to the health. A joint study by UNILU and the Faculty of Medicine of the Katholieke Universiteit Leuven (KULeuven) (Prof. B. Nemery) recently identified the source of contamination in heavy metals found in the urine of a sample of 300 people in Katanga (Banza et al., 2009): the toxic elements present are almost all those who are naturally associated with heterogenite.
Ore and soil heterogenite carries many trace elements and toxic pollutants, and is causing a real health problem for those who operate (illegally), who transforms or even live and grow on cobalt soils.
Article available on ScienceDirect.com