ABSTRACT
The rock fragments produced by blasting which are excessively large, also called boulders, need to be broken up in order to be handled by the loading equipment and the primary crusher without causing obstruction. The methods in use today for secondary fragmentation are classified in two groups: the first, where explosives are used inside the blastholes or in contact with the surface, and the second by special or mechanical means. The fragmentation by placing the explosive in contact with the surface is carried out with shaped charges or, more often, with charges made up of several small caliber cartridges. The hydraulic hammers have a utensil which hits the rock repeatedly until fragmentation is achieved. In a similar manner to the antiquated method of breaking ornamental rocks with metallic wedges, nowadays hydraulic equipment is available that can be mounted on the boom of a mobile unit.
