Simulation of industrial comminution circuits for design, optimisation and control

Industrial comminution circuits are capital and energy intensive unit operations. In a typical mineral processing plant, comminution circuit accounts for about 50% to 75% of the plant power consumption and the operating cost is also very high. Therefore, considerable economic benefits can be achieved by accurately designing the processing circuit and operating the plant at optimal conditions using modem control techniques. The parameters of process models for crushers and grinding mills can be accurately determined from single particle fracture tests and plant surveys. Hydrocyclone model parameters can be determined from classification tests. The comminution circuit simulation model constructed using these individual process models can then be used for design, optimisation and control purposes. The comminution circuit simulation model can be interfaced with notation model to optimise grind-recovery relation to achieve optimal plant performance. A case study is presented on the optimisation of comminution circuit of a plant treating 135,000 tonnes/day of porphyry copper and gold ore. The results of this study indicates that by optimising various comminution stages, the copper and gold recovery could be increased by approximately 3% which will, result in significant economic benefit. The uses of these simulation models for processing circuit design and for process control are also discussed.