Recent analysis of backfilling material has shown that a finer size
distribution is preferable for stope filling. In order to increase crusher
throughput and pit productivity, a reassessment of the quarrying operation
was conducted. Part of that reassessment was a review of blasting
practice. Six means of reducing the average muckpile fragment size were
examined. Different blast initiation and charging options were compared,
and patterns using smaller hole sizes were designed, analysed with the
JKMRC 3x3o software, then drilled and fired. The ground vibration and
face movement was recorded and compared. To determine whether the
Kuz-Ram model could be used in an economic analysis of the quarry
operation, the fragmentation distribution of the small diameter hole blasts
was determined. Photographs of the muckpiles were taken and digitised.
However subsequent analysis indicated that a satisfactorily large photo
sample was only obtained from the smallest diameter hole blast. The
Kuz-Ram fragmentation model prediction was found to be within the
confidence limits of those results. An engineering and cost comparison
between the blasts was made.