ABSTRACT
The desired degree of fragmentation also depends on the type and size of equipment, which is used for the subsequent handling of the rock. Large loaders and crushers allow larger fragmentation, but it is a common misconception that larger fragmentation can be obtained because large loading, transportation and crushing equipment is used. The large size equipment is designed to handle large volumes of material, not large size material. This analysis was conducted to study the influence of the size consist of the feed material on the output of the primary crusher. The cost of blasting and the cost of crushing in the primary crusher were calculated for the degree of fragmentation of 1.1 and 4.0 of the blasted rock. The degree of fragmentation is an average size of a lump in a rock mass divided by an average size of a lump of the blasted rock. The conclusion of this analysis is that with the same blasting materials the cost of bigger fragmentation of the rock is higher than the cost of that fragmentation in the primary crusher. The excessive fragmentation of the blasted rock is not economically justified.
