Otimização do teor de corte e seu impacto nas operações da Samarco

Abstract

Cut-off grade is a fundamental parameter in mining, as it defines the separation between ore and waste rock, varying according to the type of ore and mineral processing method adopted, directly impacting the Net Present Value (NPV) and the economic viability of mining projects. Since the 1960s, deterministic methods for optimizing this grade have been developed and incorporated into mine planning software. This work presented and validated a new methodology for optimizing the cut-off grade for the Alegria Mine of Samarco Mineração S/A, which uses off-road trucks and conveyor belts in its mining operations. The approach proposed in this work adopts a variable cut-off grade based on the LOIc (Lost on ignition of the concentrate), adjusted at each mine level and in contrast to traditional methods of applying the cut-off grade. This methodology proved effective in controlling the LOIc, positively influencing the productivity of the concentration, pelletizing, and pipeline transport stages. Furthermore, the application of variable cutoff grades allowed for greater stability of the average LOIc grade throughout the company's production plans, especially in concentrators with lower capacity to process ores with higher LOIc grades. The study concludes that the adoption of a variable cutoff grade is a robust tool that positively impacts the entire production chain, ensuring greater efficiency and sustainability of the operation.