Application of geometallurgy to develop predictive models for acid consumption on Tschudi copper heap leach operations

Abstract

This study presents the application of geometallurgy to develop predictive models for acid consumption at the Tschudi copper heap leach operations in Namibia. The acid heap leach process, integral to the extraction of copper from low-grade ore, requires a substantial amount of sulphuric acid, which is a major cost driver. Accurate prediction of acid consumption is vital for budgeting and cost management. The model development utilizes historical processing data, including mineralogical and lithological composition of the ore, to predict acid consumption during the curing and leaching stages. Multivariate regression analysis was employed to establish relationships between mineral species and acid consumption, resulting in a predictive model that considers the geological variations within the ore body. The model incorporates three distinct leaching stages, each characterized by exponential changes in acid consumption, and is calibrated using actual plant data to improve accuracy. The findings reveal that, after calibration, the model predicts acid consumption with an average error of 5%, with significant reductions in error for slow kinetic regions. This model offers a robust tool for enhancing operational efficiency, improving acid usage estimation, and optimizing overall leaching costs in heap leach operations.