A model for High Pressure Grinding Rolls (HPGR) was developed in this work based on thewidely used Population Balance Model (PBM). This approach uses a variety of different func-tions one of which is the breakage distribution function. The methodology to determine thefunction parameters is presented and using these values, the model was compared with realprocessed materials from an HPGR pilot plant, with tungsten ore as the test material. Theresults of the model parameter determination, and the product of the comminution in theHPGR, showed the dependency of material breakage on the material characteristics, and onthe operative and process conditions. The model presented is reasonably robust, showingless error than the 3.0 Root Mean Square Error when compared with a heterogeneous feedparticle size distribution material. The operational gap was also studied, and its dependencyon the feed particle size, porosity, moisture, and specific pressing force was proven.