| Fragmentation is a major concern of any blasting operation. Information on the degree and size distribution of fragments within a blasted rock mass is essential for efficient rock loading and crushing operations.; Detailed literature review shows that majority of the previous researchers estimated blast fragmentation by considering four basic variables, i.e. rock properties, explosive properties, drilling pattern and bench geometry. However, when considering the effect of burden on rock fragmentation, simplified assumptions were made and its variability along the bench height was often ignored.; In reality, because of the non-uniform burden along the bench height, the actual powder factor in the front row of holes could differ significantly from the one estimated assuming uniform burden. This will be more so if the bench is highly irregular and has significantly different toe and crest burdens. Ignoring this fact may result in a poor fit of the existing fragmentation models for the actual data. Research in this thesis demonstrates this fact and the results underscore the importance of considering the true bench profile for the blast fragmentation analysis.; For the present work, the irregularity of the bench profile and the resulting non-uniform burden was estimated using the laser profiling technique. A new rock fragmentation model, FRAGM, which considers the variability in burden, was developed and verified by comparing with actual blast results from a West Virginian limestone quarry. The developed model can be used as a quick and reliable means to predict or assess the rock fragmentation before or after a blast. |
