The Morrell method for predicting the specific energyconsumption of conventional crushing, High Pressure Grinding Rolls (HPGRs), and tumbling mill equipment is well known and widely applied in the design of comminution circuits. The method is equally applicable to assessing the performance of operating comminution circuits. The Morrell method is described in full detail in Morrell (2004b, 2008, 2009); the GMSG Morrell guideline is essentially a practical condensation of these works. The guideline reviews the data required for the analysis, including hardness characterization data generated from the SMC Test® (see Annex A) and the Bond Ball Mill Test Work Index (WiBM; GMSG, 2016a), and the Morrell equations and their application (see Annex B). A worked example is provided in Annex C.
