Audiometric Control System of Wet Semiautogenous and Autogenous Mills

Abstract

The audiometric control system of commination process introduced in this paper has been developed at the concentration plant of Outokumpu Cy, Vuonos mine.The material handled in the grinding circuit a low—grade nickel ore. The high Variability of the type of ores handled (serpentinite, chlorite, talck, black schist) makes the grinding process a very fluctuating one.The control system which has been developed is based on the noise emitted by the mill. Equipment was developed for selective measurement of the noise and the information given by this equipment was found reliable enough to serve as the basis for an automatic computer control system, in which the controlled variable is the noise and the manipulated variables are the components of the feed.A mathematical process model was experimentally identified in order to tune control algorithms.In the course of long-term testing the control system developed has been found advantageous for maintaining the mill at maximum capacity.The capacity within the audiometric control system was found to be higher than with the power control system used before. The main reasons for this higher capacity are the increased throughput of the ore and the decreased number of serious disturbances.