Melbourne, A, Andrade, W, Biulchi, F, Ribeiro, M, Lima, C & Santos, F 2020, 'Pillar recovery with WebGen™ 100 wireless technology, Nexa Resources Vazante – Brazil', in R Castro, F Báez & K Suzuki (eds), MassMin 2020: Proceedings of the Eighth International Conference & Exhibition on Mass Mining, University of Chile, Santiago, pp. 86-90, https://doi.org/10.36487/ACG_repo/2063_0.08
(https://papers.acg.uwa.edu.au/p/2063_0.08_Melbourne/)
Abstract: Vazante is an underground mine owned by Nexa Resources group that uses VRM (Vertical Retreat Mining) as predominant mining method, which involves leaving ore pillars in the mined stopes. These pillars have the function of stabilizing the open stope and minimizing dilution by limiting the hydraulic radius. The recovery of these pillars is financially desirable but making it operationally feasible is not simple and involves extra costs and cycles with scalling, backfilling the open stope, reinstalling infrastructure needed,
accessing previous blasted areas, drilling, charging with explosives, and subsequently firing and then mucking out the blasted material out. The first wireless blasting system, WebGen™ 100, allows the mine to preload the pillar with explosives, which is initiated after the block is mined, without the need for the extra cycles described previously. The initiation systems available so far did not allow such a feat, since their operation is based on the principle of physical connection between detonator in each blasthole
and ignition source (via blasting cable or shock tube). The WebGen™ 100 system is based on magnetic induction communication, and its signal is capable of overcoming rock, water and air. With WebGen™ 100 it was possible to safely preload the pillar together with production blasts, a technique named as Temporary Rip Pillar (TRP). Thus, it was possible to reduce the exposure of people and equipment, reduce operational cycles and increase mineral recovery, directly contributing to anticipate the ore production
while guaranteeing the safety of the teams involved.