Modification of SAG mill liner shape based on 3-D liner wear profile measurements

Abstract

One area in AG/SAG milling field which has received a great attention is the optimum liner design for any application to increase the availability of mills. Since the wear profile is not uniform, the modified version of a specially designed measuring device was introduced which accurately determines the wear profile at any given point along the liner length. The procedure to build the 3-D liner wear profile was also outlined. Upon finding appropriate models, which accurately described the wear rate of the liners, with the objective of arriving at the uniform liner profile at the liner removal time, new liner designs were proposed. These not only increased the liner life time but they also decreased the scrap metal content. For any new liner design the charge behavior was studied to evaluate the location of the ball impacts. Application of the proposed method in a 9.75 × 4.88 m SAG mill indicated that the liner wear profile along the liner length was non-uniform and the highest wear occurred between 1.25 m and 2.75 m of the mill length. The liners of the first half of the mill from the feed end showed more wear (19.1 g/t) compared to that of the second half (17.1 g/t). The proposed liners unlike the pervious type did not have a uniform shape and the lifter height was increased from 152 mm to 187 mm at the section where the wear rate was high. It was believed that this new profile could arrive at a uniform profile at the liner change out time. The simulation of charge motion indicated that the impact position of charge will change only one degree due to an increase of 10 to 35 mm in the lifter height. It was predicated that the amount of scrap metal will reduce to 30% from the current value of 47% and on average the liner life time will increase by 1500 h.