Effect of liner wear evolution on wet grinding performance in a SAG mill: A CFD-VOF-DEM modelling study

• A CFD–VOF–DEM model was used to study effects of liner wear evolution in SAG mill. • Sliding motion was the dominant wear mechanism; lifters wore faster than valleys. • Mill performance remained largely stable through most of liner’s service life. • Critical transition occurred at 5000 h, where flow shifted from cataracting to cascading. • Beyond the transition point, power and breakage rate sharply dropped, wear accelerated. Liners are essential in SAG mills for facilitating cataracting and protecting the shell, but their wear alters charge flow and grinding efficiency, with downtime for liner replacement causing production loss. Most existing numerical studies have focused on dry grinding, while few have addressed liner wear effects under wet conditions. This study investigated the evolution of liner shape throughout the wear cycle and its impact on wet grinding performance in an industrial-scale SAG mill. A coupled CFD-VOF-DEM model was validated and used to simulate multiphase interactions among ore particles, grinding balls, slurry and gas, with liner evolution predicted using a stepwise approach. Results showed that the slurry flow exhibited a kidney-shaped pattern driven by particle motion, and ore breakage hotspots were mainly located in the upper bed due to cataracting impacts. This flow regime remained largely stable throughout most of the liner’s service life, particularly within the first 5000 h, during which the liner wear followed a Type A pattern, with the lifters wearing faster than the liner valleys. However, once the effective lifter height fell below a critical threshold, the charge flow regime began transitioning to cascading over the following 1500 h, resulting in a sharp decline in grinding performance and power draw, along with an accelerated wear rate. Energy dissipation analysis revealed that grinding performance was strongly correlated with normal particle–particle collisions, whereas liner wear was primarily associated with particle-liner sliding motion. Additionally, the substantial drop in energy utilization efficiency after 5000 h of operation indicated that continued operation was less economically viable. Liner replacement is therefore recommended at this stage to maintain grinding efficiency and prevent structural failure from excessive wear.