Numerous studies have been conducted in the past and models have been developed to simulate ball motions in horizontal mills. Equations and computer programs have been published to calculate falling velocity of the grinding media upon impacting the mill shell (liner). However, these equations and programs are only suitable for dry mill applications. To accurately simulate the impact of falling balls on the liners in wet mills, the authors have developed models to determine the ball impact location and velocity as the ball contacts the mill liner. Drag and buoyancy forces are considered when the ball submerges in the pulp inside the mill. Models can be used to enhance mill liner design and optimize the operation of horizontal wet mills such as horizontal ball mills. The models are applied to calculate the falling ball impact on the metal magnetic mill liners. Various scenarios are simulated and results are used to predict the performance of magnetic mill liners in various ball mill applications. (C) 2013 Elsevier Ltd. All rights reserved.