In this paper, the High Pressure Roller Mill has been used as a pre-crusher or pre-grinder for the treatment of a filter cake limestone material. The different comminution systems with or without the High Pressure Roller Mill have been investigated. Experimental results indicated that pretreatment of the material favors the subsequent wet ultrafine grinding for energy efficiency and throughput. The fineness of the ground product is significantly influenced by various pass numbers of pre-grinding with the High Pressure Roller Mill. The formation of the micro-cracks in the particles under the compressive loads was also discussed in order to elucidate the role of the High Pressure Roller Mill as a pre-grinder before the attrition mill.