Artisanal and small-scale gold mining (ASGM) in Tatelu Village, North Sulawesi, has shifted from mercury amalgamation to cyanide leaching. However, gold recovery remains inefficient, requiring process optimization. This study uses multiple linear regression analysis to evaluate the influence of grain size and slurry density on gold dissolution. The results indicate that grain size plays a dominant role in leaching efficiency, while slurry density, pH, temperature, dissolved oxygen (DO), and cyanide concentration have statistically insignificant effects (p > 0.05). Laboratory tests show that finer grain sizes enhance dissolution, with the highest recovery rate of 89.08% achieved at 75% passing through 44 µm with a slurry density of 25% solids after 72 hours. However, for practical ASGM operations, a grain size of 75% passing through 74 µm with a slurry density of 35% solids is preferable, achieving 84.26% dissolution in 72 hours while maintaining higher processing capacity. Statistical findings also indicate that increasing slurry density reduces leaching efficiency due to limited oxygen diffusion and increased solution viscosity. These results provide a data-driven approach for improving cyanide leaching efficiency in ASGM, increasing gold recovery rates by more than 20% compared to current practices while ensuring economic feasibility and environmental sustainability.
Nurjaman et al. (Sat,) studied this question.