The gold industry has long been restricted by the lack of instrumentation capable of measuring gold in real time and on-line down to parts per billion (ppb) levels. This lack of capability limits limited the operators and management of the process as historical data is, for the most part, often delivered after any opportunity to change of process strategy can be employed had passed. Hence the plant chemistry is always run in a rich state in order to ensure there are no costly negative excursions. Despite the process being run in this rich state there are still too many excursions and often with significant gold losses to tail occur. At the same time control of carbon concentrations in the leach circuit is ad-hoc at best with only manual sampling carried out sporadically during the shift. Likewise, gold loadings on the carbon can only be seen obtained through manual sampling and results are often returned after the optimum time for carbon transfer has passed. To address these limitations Gekko Systems (Gekko) has entered into collaboration agreements with Curtin University for the Carbon Scout, CSIRO for the OnLine Gold Analyser (OLGA) and Rockwell Automation for development of the Trinity Metal Tracker. The Carbon Scout: continuously monitors all tanks for carbon concentrations, dissolved oxygen, pH, and soon to have gold concentrations on carbon. The OnLine Gold Analyser (OLGA): continuous measurement measure of low grade gold down to ppb levels. This technology is more accurate than fire assay as it utilises a far larger sample across 100% of run time. Trinity Metal Tracker: Auditable software for real time metal tracking and accounting. The combination of all these technologies combined will provide the first real time automation for a gold CIL/CIP recovery circuit. For the first time a gold plant will be seen in real time and process control will run from feedback data supplied by the system. A fully auditable metal tracker will give automated data as and when it becomes available as well as handling retrospective data back to the system. Sampling error will be highlighted with projected and actual results displayed in as close to real time as possible. Tracers in the ore will lead to automated auditable mine ore block and stockpile reconciliations. The system will provide auditable control to enable real time process feedback for existing automation infrastructure.
CITATION:Gray, A H, Craig, E, McGrath, T and Staunton, W P, 2019. Collaboration leads to real time control of gold leach circuits, in Proceedings World Gold 2019, pp 604614 (The Australasian Institute of Mining and Metallurgy: Melbourne).