Comminution and classification are the two major unit operations involved in the processing of pure minerals from its ore rocks. In the current paper, an assessment is made on different numerical models used for the prediction of fluid and solid flow properties in tumbling mill, hydrocyclone and dense medium cyclone (DMC). A detailed discussion on the selection of suitable turbulence and multiphase models for the accurate prediction of flow field in hydrocyclone is made by comparing the predictions among and against experimental data. The additional requirements for accurate performance predictions at high feed solid content is elaborated. The drawbacks of DPM model and the usage of CFD-DEM coupling technique to predict the coal partition curve in DMC’s has been elucidated. The discrepancies between DEM, CFD, one way and two way coupled CFD-DEM predicted mean flow field and particle dynamics against experimental measurements in tumbling mills also made in detail. © 2020, © 2020 Institute of Materials, Minerals and Mining and The AusIMM Published by Taylor & Francis on behalf of the Institute and The AusIMM.