In mining when processing or transporting solids in a liquid slurry it is important to know qualitative and quantitative information about the solids expected to pass through the equipment being considered. Impact abrasion of heavy or larger particles for alloys and rubber and sliding abrasion of finer particles for urethanes. The qualitative info for a typical mining circuit is as follows:  The ore is crushed① to a consistent but often sharp size often about 1” Then processed in a SAG② or Rod mill to about 0.5” Off to ball mill③ with starting dimensions of 0.25” Pulverized fines are separated from cyclone overflow④ to about 0.020” or less These important fines are floated over the weir in the Flotation cells⑤ and recovered for final processing The tailing or non-essential materials are pumped⑥ to settling ponds for process water recovery and reclaim. This info will help with material selection. Distribution describes the quantitative amount of these particles in any given sample removed from a process step in question. Typically characterized as “d” (for distribution) the sample will be reported as “d90” or 90% of the sample will be below some particle size as measured by passing the sample through a mesh screen or “Sieve” of a given size. “d50” means 50% of the sample will pass through a smaller size. See the drawing below. This info will help with equipment performance specifications.