Burden estimation using relative bulk strength of explosive substances

Abstract

The burden is the distance from a blast hole to the nearest free face at the time of detonation. This paper presents a new concept in burden estimation during drilling and blasting pattern design for surface mines and quarries, with the purpose of reducing over-sized rocks. The new concept can contribute significantly towards profitability and therefore, optimisation of the drilling and blasting parameters. However, the concept developed is based on estimating the burden as a function of relative bulk strength of the explosives. Digimizer software facilitated the analysis of the grain size of the previous fragmentation, over-sized rocks and the fragmentation grain size from trial blasts at Los Caliches quarry in the Province of Holguín, Cuba. This concept is easy to use and acceptance of the approach requires other mines to conduct trial blasts to test the design theory. The mean grain size surface area obtained from the trial blast was 131 cm², which was within the acceptable rock grain-size surface areas at the primary crusher for the aggregate beneficiation.