Solution flow behavior in response to key operating parameters in heap leaching

Solution percolation through packed ore beds provides essential substances for leaching reactions to occur and mobilizes reaction products through ore beds. Understanding key factors that control solution movement is the prerequisite to forecasting and optimizing the performance of a heap under leach. In this study, the responses of the solution flow behavior to four key design parameters were investigated using the HeapSim-2D model: irrigation rate, dripper spacing, heap height, and initial moisture content. The model was calibrated and validated against monitoring data provided by the Quebrada Blanca mine, a copper heap bioleaching operation located in northern Chile. The modelling results showed that solution breakthrough times were shorter at higher irrigation rates, larger dripper spacing, lower heap heights and higher initial moisture contents. However, higher irrigation rates and larger dripper spacing resulted in more uneven moisture distributions at steady state. After irrigation was terminated, the bulk of the mobile solution retained in the leach unit was drained out within two days. The modelling results can provide mine operations with information on how to control key parameters that determine the solution flow behavior for the optimization of heap leach design.