Comminution is the process of reducing the size of particles by crushing or grinding. In this experiment four crushers are used to reduce a basaltic copper ore from 4 inch to 100% passing 20 mesh sieve. The four crushers are: Jaw Crusher, Gyratory Crusher, Short Head Crusher, and Roll Crusher. The ore sample is weighed and classified before and after passing through each crusher. Particle size distribution and losses are determined for each.