Mineral Crushing and Grinding Circuits

Mathematical modelling and automatic control of mineral crushing and grinding circuits have been studied at the Queensland Julius Kruttschnitt Mineral Research Centre for several years. While much is still to be done, it is considered that knowledge of the subject has reached the point at which a useful monograph may be published. The emphasis in this monograph is on the simulation and control of industrial machines and circuits. It was with some misgiving that I decided to restrict the discussions on the theoretical aspects of size reduction, size separation and material balances to include only the information which is necessary to understand the simulation and control sections. A complete discussion of these subjects would have required a much longer monograph. However, references for further reading in these cases are cited in the bibliography. The order of presentation follows an order developed during many series of lectures which have been given to graduate and undergraduate students, plant metallurgists and research scientists during the past ten years. Considerable use has been made of numerical examples to illustrate models which have been discussed. The reason for this is that models are not generally understood until calculations are carried out using these models. A major objective of comminution is to liberate minerals for concentration processes and a model of mineral liberation is discussed. This discussion is also restricted for the reason mentioned above. Much of the work on which this monograph is based was carried out as thesis projects by candidates for higher degrees at the University of Queens-land while attached to the Julius Kruttschnitt Mineral Research Centre. Their work has been of a particularly high quality and I have been fortunate to have had the opportunity of working with them. The theses are listed in the bibliography. Case studies are most important in a monograph of this type to illustrate the practical application of the concepts which have been introduced. The case studies which are described cover several different types of grinding circuits, and the Julius Kruttschnitt Mineral Research Centre has be en associated at some stage or another with each case study except that in which the development of a control system for the semiautogeneous mill circuit is discussed. This work was carried out jointly by Cyprus Pima Mining Company and Industrial Nucleonics Corporation, and A wish to thank these companies for their ready response to my request for the study.