REAL WORLD DEVELOPMENT AND APPLICATION OF A GOLD LEACHING AND REAGENT CONSUMPTION MODEL TO OPTIMISE CIP/CIL PROCESS PROFITABILITY

摘要

Real-life use of gold cyanidation models is currently limited to a small number of sites, due to the following main reasons: site specificity of each model, reliance on specialised measurements, and the exhaustive set of parameters required to describe the many competing reactions occurring in a continuous leach process. More general models are of interest in academic circles but tend to be verified on a limited range of ore samples and require input information that rarely mirrors real-life data collection practices on gold mines. To address these shortcomings, a gold cyanidation model (LeachPRO) was conceptualised and developed by Orica Ltd to display the following characteristics:Data inputs are principally, commonly collected measurements on gold processing plants ;Other regularly available measurements (i.e. Bottle Roll extended leach results, Free & WAD cyanide measurements, Diagnostic leach results) can be used to enhance the fit of the model if available ;Outputs allow for manipulation of the most commonly varying process optimisation parameters (throughput, head grades, reagent dose rate and location etc) and reporting results in terms of gold dissolution and reagent consumption ;The model must be adaptable across a wide range of sites via inclusion of deleterious elements such as copper and sulphur, and allow further development to include additional elements. The development path included modification of previously published models to change data input sources, adapt for continuous operation, and include real-life impacts such as HON volatilisation and tank bypassing. By undertaking a 'calibration' process for each site, fitting the model to the real process measurements & performance before scenario analysis, the model is usable for a wide range of processing operations and configurations. The real world performance of the model on operating sites is included to evaluate its performance in optimising recovery by manipulating pH, Cyanide, DO, residence time and other variable process parameters.