Enhanced cyanide management through ASTERTM process technology
ASTERTM is a proprietary Gold Fields technology that offers a safe, efficient and environmentally responsible
alternative to conventional cyanide management and process water disposal. ASTERTM utilises a blend of
naturally occurring microbial species to destroy cyanide and thiocyanate present in recycled tailings process
water, following the leaching process. ASTER™ negates the need for costly and environmentally harmful
chemicals that are commonly used in cyanide destruction, by using bacteria and fungi that are wholly nonpathogenic.
This not only limits ASTER™’s environmental impact, but also offers significant cost savings
compared to rival chemical processes.
In addition, the operational efficiency of ASTERTM has now been proven on a commercial scale. During 2011,
this was demonstrated at the first ever commercial ASTERTM plant, operated by Barberton Mines in South Africa.
Process water from the plant demonstrated only trace levels of cyanide, as well as thiocyanate concentrations of <1ppm. This is below what most chemical processes are capable of achieving and well within the International
Cyanide Management Code (ICMC) cyanide concentration limit of 50ppm.
ASTER™ can be used to further enhance Gold Fields BIOX® treatment technology, which has very low tolerance
of cyanide and thiocyanate and thus requires tailings process water to be detoxified prior to reuse. As a result,
the growing global demand for BIOX® will also generate marketing opportunities for ASTER™. Several BIOX®
operations are already investigating potential application of ASTER™. In addition, it is likely that the market for
ASTER™ will be driven by increasingly stringent environmental legislation around the world, as well as a growing
number of companies signing up to the ICMC.
Gold Fields is currently investigating opportunities to use ASTER™ to enhance cyanide management at its Cerro
Corona mine and Chucapaca project in Peru.