Impactos da definição do teor de corte no modelamento de envoltórias de teor e estimativa de recursos de um depósito de cobre

Abstract

The study evaluates the impact of modeling cut-off grade on mineral resource estimation in a real IOCG-type Copper deposit (Iron Oxide Copper Gold). The analysis focuses on the variation of grade shells modeled with different cut-off grades, ranging from 0.05% to 1.00% Cu, while keeping the high-grade envelope constant. Drilling data and implicit modeling techniques using Leapfrog Geo software were employed. The results show that as the cut-off grade increases, there is a progressive reduction in both mass and contained metal, while the average grade increases. However, in the intervals below 0.15% and above 0.85% Cu, variations become less significant, indicating parameter stabilization. Scenarios between 0.10% and 0.20% revealed potential gains in contained metal, although accompanied by a proportionally greater increase in the total resource mass. It is concluded that cut-off grade adjustments should consider not only grade values but also geological aspects, in order to preserve the coherence of the model with the deposit’s geological reality.