Influence of mineralogical variability on the efficiency of gravimetric gold concentration: a comparative study in the ASM sectors of Ocoña and Chala, Arequipa, Peru

Villanueva-Zela X.N.; Pacheco-Anco A.; Colque-Riega S.P. · Boletin de Ciencias de la Tierra (2026) · DOI: 10.15446/rbct.n59.126432

Resumen

This study compared mineralogical characterization and gravimetric concentration efficiency in ores from Ocoña and Chala (Arequipa) to identify recovery-controlling factors. Representative sampling, optical microscopy, X-ray diffraction (XRD) with Rietveld refinement, and Falcon concentrator tests (P80 < 74 µm) were applied. Results showed that Ocoña achieved significantly higher average gold recovery (86.50% ± 7.92) compared to Chala (81.80% ± 4.81) (p = 0.021). This difference is explained by Ocoña’s higher free gold content (>90%) and coarser particle size (D₅₀: 125–260 µm), whereas Chala exhibited higher arsenopyrite (up to 8.5%) and finer gold (D₅₀: 32–45 µm) associated with sulfides. Findings highlight deposit heterogeneity in ASM and the need for site-specific processing strategies, based on comprehensive mineralogical analysis, to optimize recovery and foster sustainable mining practices. © The author; licensee Universidad Nacional de Colombia.

Instituciones: Universidad Nacional de San Agustín de Arequipa