The HPGR is capable of handling particle sizes up to approximately 50mm. The essence of the process is to avoid single particle crushing and to aim for a compressive grinding of the material in the particle bed Single particle crushing would increase the wear of the roll surface through high point-loads and shear, and would cause damage to the autogenous wear surface. For ideal inter-particle compression, grinding the feed particle sizes should be smaller than the operating gap between the rolls. In actual applications, the top size of a feed distribution can contain particles of up to about 70% greater than the operating gap.