Plantwide Control: The Next Step In Mineral Processing Plant Optimization

Plantwide control is the networking and coordination of individual control systems throughout the plant to enhance plant performance. The high level decision making involved in this coordination is used to achieve overall plant optimization. Decisions must be based on knowledge and information moving between control systems in both downstream and upstream directions and on management information systems containing financial data on the impact of coordinating actions. For example, certain quantitative descriptors of upstream operations are passed to the downstream control systems to prepare those operations for the feed material they will receive. Likewise, other quantitative descriptors of downstream operations are passed to upstream control systems to modify their output. In this case, setpoints are determined throughout the plant which maximize profitability, given current ore conditions and plant operating constraints. Due to the wide area coverage of this coordinator, it is forced to draw on several diverse information and knowledge bases. Such a coordinator, then, must rely on a combination of heuristic logic, model-based control and neural networks to unify the knowledge bases as well as to take advantage of their strengths and to compensate for deficiencies. A description is given of control systems for primary and secondary grinding and flotation at a large copper concentrator and how they are being integrated to achieve plantwide control. Financial implications are discussed.