A model-based feedback control strategy for heap bioleaching processes

In this paper we propose a feedback control strategy to increase the copper recovery in a heap bioleaching process. The control strategy is implemented using internal model control based on a multivariable linear state-space model obtained by the maximum likelihood method. The linear model describes the variations of the average temperature around a nominal trajectory. This trajectory is obtained as the response to nominal inputs that have been proved to work well in real leaching applications, and is computed using a comprehensive high complexity mathematical model developed by BHP Billiton Innovation. The results show that significant increments in copper extraction can be obtained using limited control actions with the proposed feedback strategy.