The Biological Oxidation (BIOX(R)) Process for the treatment of refractory
gold ores was commercialized in 1988. During the last decade, the technolog
y has developed into a mature, commercially viable process, with five addit
ional operations commissioned, including operations at Sao Bento in Brazil,
Harbour Lights and Wiluna in Australia, Ashanti in Ghana and Tamboraque in
Peru. With ongoing development, the efficiency and cost effectiveness of t
he process have both improved making it an attractive alternative to conven
tional refractory treatment processes such as roasting and pressure oxidati
on. The bacterial culture is robust and can withstand the normal fluctuatio
ns experienced on an operating plant. The plants are simple to operate, mak
ing it ideal for remote areas. The scale-up potential of the process has be
en proven, and it can be applied to large refractory ore bodies. The proces
s is environmentally friendly. Neutralization of plant effluents produces p
recipitates that comply with the most stringent environmental regulations.