Blasting Fragmentation Study Using 3D Image Analysis of a Hard Rock Mine

Abstract

Rock blasting with explosives is the first stage of rock fragmentation and plays a key role in the results of the mining chain. Fragmentation optimization is achieved by considering the energy efficiency of the explosive, the optimal distribution of explosive energy in the rocky mass, and the programmed and controlled release of explosive energy during blasting. The quality of fragmentation is usually performed using tools that estimate the sizes of fragments via the analysis of two- or three-dimensional images. This article presents a study of the rock fragmentation optimization of very compact itabirites, based on four blasting tests, performed in a different way from the conventional blasting design. The fragmentation analysis was performed using the PortaMetricsTM tool, and compared with the Kuznetsov and Rosin–Rammler particle size distribution model, to compare the reliability of this tool. Finally, the mine productivity after blasting was estimated from the particle size distribution obtained in the tests. The model presented idealistic results considering the technical parameters used in the equations. However, the PortaMetricsTM tool suggests good performance for the preliminary evaluation of blast design.

Keywords

• 80% passing size
• blasting design
• very compact itabirite
• mining productivity