Analytical methods developed by the CSIRO have helped New South Wales’ Cowal Gold Mine meet its stringent environmental conditions and become the first mine in Australia to comply with the International Cyanide Management Code.
The methods use high performance liquid chromatography (HPLC) to provide accurate quantitative determinations of the chemical composition of samples taken along the course of the ore treatment process.
CSIRO senior research scientist Paul Breuer told MINING DAILY the methods allow mine operators to track and manage both the cyanide employed to leach the gold from its ore and the reagents subsequently added to destroy residual cyanide before discharge into the tailings dam.
“The national pollution inventory reporting procedure requires all mine sites to account for the amount of cyanide that is present on-site,” Breuer said.
“That means they need to account for everything, including the cyanide that is reacted off.
“In the past, minesites have estimated the amount of cyanide onsite rather than used quantitative data to determine its exact level.
“The CSIRO, together with researchers from the Parker Centre, developed an analysis method that helped Cowal gold Mine meet its environmental standards in a way that increased efficiency and saved on reagent costs.”
Chemical species in solution pumped through a column packed with an ion exchanger will separate out according to the strength of the physical interactions between them, Breuer said.
Each species takes a characteristic length of time to travel through the column.
All the different species can be detected, identified and their concentrations measured using their characteristic absorption.
Breuer and his research team were able to determine appropriate solvents, ion exchange materials and detection methods for precise discrimination and measurement.
For the full article check out the April edition of Australian Mining.