Supervisory Fuzzy Expert Controller for Sag Mill Grinding Circuits: Sungun Copper Concentrator

Successful control of Semi-Autogenous Grinding (SAG) mill circuits has been the subject of many researches and main concern of plant operators for years. Distributed Control Systems (DCS) have had some degree of success in the mineral processing circuits, but maintaining operation of a SAG mill on the edge of its full capacity is not easily achievable by DCS. Advanced control systems, however, are a relatively new opportunity to successful control of mineral processing plants. This article presents the basis of a supervisory fuzzy expert controller for SAG mill circuits. Although leading companies in control and automation have their own commercial packages, this supervisory controller is coded in Matlab using Mamdani method and is able to connect to plant lower level control system. In the proposed controller, fuzzy system calculates optimum set points to the plant DCS control loops, enabling them to change the manipulating parameters to reach the new set points. This controller was installed, tested and verified in a copper grinding circuit. Results showed 1.8% increase in mill throughput, 3% decrease in power draw and more stable feeding regime at the same time.