Investigation of the relationship between rock brittleness and brittle fragmentation

Fragmentation characteristics can provide a good basis for identifying the brittleness level and failure mode in rock materials. Investigating the rock fragmentation is important in many rock mechanics applications such as evaluating the blasting efficiency, wear of cutting tools in mechanized excavation, mineral processing recovery, and rock bursting intensity. Fragments generated from rock failure and through each rock mechanics application are different in size and morphology. The purpose of this research is to find the relationship between fragmentation characteristics and brittleness under static compressive loading. Thus, the fragmentation features including size, mass and shape for Gosford sandstone and granite were analyzed. The fractal dimensions were calculated through the mass-size statistical distribution and then compared with the brittleness levels obtained from various methods. It was found that the rock types with different brittleness values possess different fragmentation properties. The highest quantity of fragments generated from granite owing to its higher level of brittleness. An inverse relationship was found between the fractal dimension and brittleness index that can be used as an effective approach in understanding of rock failure mechanisms.