ELECTRICAL RESISTIVITY APPLIED TO OPTIMIZATION OF BLASTING DESIGN AT PRODUCTION BENCHES: A CASE STUDY AT ABÓBORAS MINE, QUADRILÁTERO FERRÍFERO, MINAS GERAIS - BRAZIL
Andre Luiz Vieira, Marco Antonio Braga, Jair Carlos Koppe, Lorena Andrade Oliveira and Maria Filipa Perez da Gama
ABSTRACT
Quadrilátero Ferrífero is one of the main regions of iron ore production in the world. The action of the weathering processes promotes the conformation of compact rock immersed in friable material. The usual model of blasting applied in production benches, with blast drillholes distributed homogeneously, produces boulders of compact rock, which are impracticable to extract and grind, causing impacts on daily production of iron ore. Therefore, this work proposes a methodology capable of overcoming this problem caused by weathering, using the electrical resistivity method. The application of it was carried out at the Abóboras mine (VALE S.A.), and was able to differentiate two types of materials, interpreted as compact and friable itabirite. With the use of the electrical data, it was possible to generate a geophysical model that allowed to determine the position of the compact itabirite boulders. From this model, it was possible to optimize the blasting design, with higher concentration of detonation drillholes where the model indicated the compact rock. With the appropriate tests, it was observed a 75% decrease in the amount of boulders present in the fragmented material as compared to the usual model. Consequently, there was a significant increase in ore loading effectiveness, thus optimizing iron ore production.
Keywords: Applied geophysics, iron ore, mining.