OFFICIAL Design and Implementation To reach the objective of reducing dilution and stabilizing blend quality, the site implemented a three‑dimensional blast movement modeling workflow using OREPro™ 3D. The workflow transformed the in‑situ grade‑control model into a post‑blast model and issued optimized dig‑layers that reflect actual material displacement after blasting. Ahead of modeling, mineralized lithologies were classified by total organic carbon (TOC)—for example, dacite (TOC < 0.5) and carbonaceous (TOC > 0.5)—so the optimized post‑blast polygons directly supported blending decisions in the plant. OREPro™ 3D was prepared with site data and blast designs to simulate movement across the blasted volume; the resulting post‑blast model provided geologists with greater confidence in the composition of dig‑layer polygons and the ore/waste delineation during excavation. Operationally, mining proceeded against the modeled post‑blast dig‑layers rather than in‑situ boundaries, aligning shovel instructions with the TOC‑based classification. This practice targeted lower dilution and more reliable blends to the crusher, integrating seamlessly with Santa Luz’s existing grade‑control and reconciliation routines. RESULTS AND DISCUSSIONS Controlled Blasting Near Sensitive Infrastructure The A3N pit successfully achieved safe production blasting near critical infrastructure, eliminating the need for any relocation of facilities. Throughout 2025, blasting activities displaced more than 1,016 kt of material while maintaining full compliance with the vibration limits established by NBR 9653 at the administrative buildings and adhering to the more conservative threshold of ≤ 5 mm/s at the water dam, as illustrated in Figure 5. All protected areas remained free of flyrock: during blasts in Sector I, no projections were recorded, and in Sectors II and III, the respective stand‑off limits of 50 m and 100 m were consistently respected, as shown in Figure 7. From an efficiency standpoint, the standard powder factor planned was reduced by approximately 18%. In Sector II, refinements increased MIC from 18 kg to 22 kg and reduced stemming from 4.0 m to 3.6 m, enabling roughly 50% pattern expansion and associated cost benefits while maintaining control. When combined with the avoided relocation of infrastructure, the project delivered an estimated economic impact of US$ 1.6 million.
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