Optimisation of Grinding Circuits

The objective of the optimisation component of the grinding circuit control hierarchy is to provide optimal steady-state setpoints for the Advanced Regulatory Control (ARC) layers of the control scheme. That is, the optimiser provides the correct steady-state operating point for certain variables of the plant, and the ARC provides the fast, real-time dynamic control of the equipment to its constraints and to achieve those optimal operating points.

There are a limited set of process variable setpoints which may need optimisation. For maximising the throughput of the grinding circuit, most of the setpoints of the grinding ARC schemes relate to fundamental equipment and process constraints. Maximising the performance of the grinding circuit is done by pushing the equipment up to these constraints. These constraints don’t change unless the equipment or flowsheet changes. However, in general, there are some plant variables which optimal setpoints which need to be adjusted in real-time. The set of these variables needs to be determined after analysis of the ore, flowsheet and control schemes, taking note of whether sufficient degrees-of-freedom (or manipulated variables) are available to achieve these setpoints, after the ARC has “consumed” most of them to maximise real-time performance.