2D DEM verification: Load behaviour and forces on a lifter bar

The Discrete Element Method (DEM) is a model that is used to simulate the m otion of the media in a grinding mill. The sum of the energy that is lost i n inter-media and media-wall collisions represents the power drawn by the m ill. The fact that the DEM predicts the power drawn by grinding mills over a large range of diameters has been used to show the validity of the DEM. H owever, the power drawn by a mill is a function only of the sum of forces o f the load on the shell liners. A more accurate and detailed validation of the DEM would be to measure these forces as a function of angular position as the liner moves under the load, and to compare these measurements with p redictions generated using the DEM. An experimental mill has been developed to reproduce exactly what the 2-dim ensional DEM simulates. The 0,55 m diameter mill has a length of 0,023 m, w hich is fractionally larger than the diameter of the media used in the mill . One of the Lifters in the mill has been instrumented so that the forces o n the lifter can be measured as the mill rotates. The DEM simulation will b e used to predict these forces. This will give experimental evidence of the validity of the the DEM for modelling load behaviour in rotating grinding mills.