“… Asymmetric wear of operative wheel blades, variable fan and grinding capacity between two successive repairs, Fig.2 [1,2,4,5]. -The measurements of the necessary mode quantities for mill fan in the DCS or SCADA system are rather inaccurate due to the significant changeability of the conditions for measurements (wear, slagging, sensor pollution) and also due to the great amount of external disturbances (dust and humidity of fuel, imprecise dosing of coal, stohasticity of temperature of the intake oven gases due to non-stationarity of the torch position) [1,2,7,9,10].…”