Applying Wireless Initiation System to Reduce Personal Risk Exposure and Optimize Blasting Sequence and Operational Cycle Time

Vazante mine is an underground polymetallic mine that produces zinc, lead, and silver, which belongs to Nexa Resources in Minas Gerais, Brazil. The mine, a sublevel stope underground mine, mainly applies two subvariants: VRM – Vertical Retreat Mining and Open Stope. In a specific place of the mine, the geology allowed the design of a production stope with larger dimensions than the standard stopes, commonly called Super Stope. At this place, the plan was to apply both sublevel variants simultaneously. This mining block comprises rings in two different levels, with access by two ore drives on each level; the dimensions would be approximately 50 meters high, 50 meters long, and 35 meters wide. Opening the Free Face to mine the whole Stope was a challenge due to operational issues, such as hazard risks from loading over void space, exposure to uncontained places, and the impossibility of implementing the optimal blast sequence. Wireless blasting initiators have gained popularity recently due to their convenience, safety, and efficiency. This initiation system was applied to preload all the rings required to open the Free Face, ensuring a safe and optimal blast sequence. Wireless initiation prevented hazard risks, enhanced the blast sequence to guarantee the required void space, and optimized the equipment's operational cycle. The blast crew carried out the activity without exposure to the risk of loading over void space. The wireless detonators also avoided after-blast activities, which were required to provide secure access to the blast crew, optimizing the operational cycle.