3-D liner wear profile measurement and analysis in industrial SAG mills

In industrial SAG mills availability is of prime importance due to its direct impact on the economics of the process. The main single factor influencing the availability is the liner condition. The common method to determine the liner wear profile has been two dimensional and the weight estimation has been performed assuming a uniform wear profile. In this study, a method was proposed and tested to determine the wear rate accurately through building the 3-D model of liners after any given operating time. This was made possible by frequent profile measurements and using a commercial mechanical software. A specially designed liner wear profile measuring device enabled fast and accurate measurements inside the mill during the mill shut-down periods. Application of the proposed method in a 9.75 × 4.88 m SAG mill indicated that the liner wear profile along the liner length is non-uniform and the highest wear occurs 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). Due to the non-uniform wear profile, the liner removal time calculated based on the lifter heights could be very different. The difference between removal times could be up to 1.3-fold. It was found that a first order kinetics model could well be used to describe the loss of liner weight over time (R2 = 0.94). Based on the proposed method, for any given operating hours, a 3-D model of the liner could be obtained.