Rock factor prediction in the Kuz–Ram model and burden estimation by mean fragment size

Abstract

In order to use the Kuz–Ram fragmentation model efficiently, the rock factor must be determined correctly. One of the aims of this study is to provide an approach to estimate the rock factor, which represents the blastability of the rock mass, in the Kuz–Ram fragmentation model. This proposed approach is based on previous blasting data from quarry records such as blast geometry, explosive quantities and amount of coarse fragmented material to be obtained after blasting. Using the proposed approach, if the mass of the material over a given fragment size is known, the rock factor in the Kuz–Ram model can be determined for a particular site. Another purpose of this study is to estimate the optimal burden according to the intended mean fragment size using the Kuz–Ram model. Studies were firstly carried out to find the most appropriate burden for the mean fragment size intended for a quarry where the rock factor is known. After this, generalized equations were derived for the optimal burden depending on the rock factor, the intended mean fragment size, the bench height and the density of the explosive. Finally, the obtained values from the suggested relations were compared with the actual blast rounds, considering the total cost and the coarse fragmented material ratio. It can be seen that the values obtained from the proposed relationships for burden are compatible with the most cost-effective blast pattern’s parameters that were actually obtained.