Specific energy reduction in a semi-autogenous grinding mill circuit by an automatic control system

Grinding operations, especially those involving semi-autogenous mills, account for a significant portion of energy use in mineral processing. In this work, we describe the application of an advanced regulatory control strategy in a copper plant aimed at improving energy efficiency through automation. The system combines cascade and feedforward control structures to attenuate variations in the mill load, a key factor influencing energy consumption and process stability. The control scheme was integrated into the plant's existing automation infrastructure and evaluated through a three-month industrial trial. By shifting from manual to automatic regulation of the feed rate, the plant reduced the influence of process disturbances and maintained more consistent operation. The automated system achieved a 5.84% reduction in specific energy consumption and a 1.90% increase in productivity. These results demonstrate the potential of enhanced regulatory control to deliver measurable performance gains with minimal changes to existing operations.