Glycine heap leaching

The Challenge

Extraction of economic metals from copper, gold and nickel ores using glycine heap leaching as an alternative to sulphuric acid, and to reduce the use of cyanide in gold-bearing ores.

Key Findings

Glycine heap leaching technology enables extraction of precious metals at much reduced cyanide consumption.

Glycine technology is applicable to heap leaching and is scalable in a laboratory setting.

Glycine is not biologically consumed, is stable in solution and it can be recovered for recycling.

Glycine and metal glycinate complexes adsorb onto some ores with the adsorbed glycine can be removed with a salt water wash.

Financial modelling demonstrates that the technology could be the preferred option for the treatment of high acid (>30 kg/t) consuming copper ores and gold ores particularly those containing elevated copper.

The glycine technology is applicable to copper oxide deposits containing precious metals as they can be co-leached in a single stage.

For gold ores with elevated copper, the approach uses starved levels of cyanide with glycine to leach the precious metals at equivalent or better gold recoveries, reducing cyanide use.

Benefit to WA

Glycine heap leaching technology can offer the global mining industry an alternative means to sulphuric acid for copper oxide deposits particularly those hosted in carbonates; and reduce cyanide consumption in gold ores improving environmental performance.    

Keywords: glycine, heap leaching, gold, copper & nickel, cyanide alternative