A study of the load behaviour of an industrial mill was undertaken to improve the understanding of the grinding-mill process. Load behaviour was measured directly by means of probes inserted through or mounted onto mill finer bolts. Toe and shoulder positions of the load were identified. Load oscillation and premature centrifuging occurred, and the effect of this on power is investigated. Salt tests were conducted to give an indication of axial mixing. Liner bolt movement probes attached to the outside of the mill measured some aspects of load behaviour. The data has provided valuable insights into mill load behaviour.