Observer to estimate grinding mill conditions

The charge in a semi-autogenous grinding mill consists of grinding media and slurry, of which the grinding media is a combination of large ore (rocks) and steel balls, and the slurry is a mixture of small ore (solids) and water. The constituents of the charge can be represented by a nonlinear model with states and parameters observable from measurements at the mill discharge. In this paper, a transformed version of the nonlinear model is used in an extended Kalman filter to estimate the volumetric filling of grinding media (rocks and balls), solids, and water with reasonable accuracy from measurement commonly available in industrial settings. This information is of valuable importance for the control of grinding mills.