Simulation models are often used in "soft monitoring systems" to predict the effects of production and to diagnose whether the technological process meets the required standards over a given period. They also, however, show promise in the context of mineral and coal processing plants where information on process performance is typically gained from time and labor consuming laboratory tests on samples of material taken from the feed and products from the beneficiation process. Coal concentrates from raw coal are produced through gravitational separation processes in heavy media vessels and in jigs. Both processes are described by a similar model of raw coal washability characteristics and a partition curve of the machine. In soft monitoring used for the on-line identification of the partition curve (imperfection) and the washability characteristics, signals from the belt scales (yields of three products) and two separation densities from radiometric density meters are continuously compared at two different pairs of separation densities in a 3-product gravitational process in a jig. with similar signals generated in a simulation model of the process. The simulation analysis has shown that the presented soft monitoring system can be successfully used in the complex identification of a coal separation process in a gravitational washer such as a jig. It seems to be a good method for on-line determination of raw coal washability characteristics, the partition characteristics of the machine and separation. Good results for three density fractions have been obtained. The results of the imperfection in soft monitoring show that it is possible to classify the efficiency of a jig into several ranges on-line, for example: very good. good, satisfactory, not satisfactory.
