State and parameter identifiability of a non-linear grinding mill circuit model

The states and unknown parameters of a non-linear model of a grinding mill circuit are shown to be identifiable from manipulated, controlled and measurable variables. All the states in the mill and sump, the breakage rates in the mill, the mill and cyclone parameters and the mill power draw parameters can be algebraically expressed in terms of known variables. Theoretically, the tiered approach to estimate all states and parameters enables model-fitting without the need for unnecessary assumptions regarding model parameters. The analysis shows the necessity of accurate density and flow-rate measurements across the circuit, and especially the cyclone, to estimate all states and parameters. The aim is to enable non-linear model-based control through model characterisation using available real-time plant measurements.