In a typical grinding circuit ore is fed into the mills where abrasion, attrition and impact reduce its size. Usually, the grinding circuit contains at least two interconnected mills with material classifiers (e.g. cyclones) separating the fine material from the coarse (that then goes for regrinding).
The process is energy intensive with power consumption of roughly 20 to 30 MW and feed throughputs of 2,500 to 3,000 t/hr. Process variables are mill loads, motor torque and power, plus pressures and flow rates. The ground product is specified in terms of fineness.
The typical results of an APC controller are increased throughput, homogeneous product quality, reduced consumables and lower maintenance costs.