Optimization of cyanide leaching process based on grain size and slurry density in artisanal small-scale gold mining in Tatelu Area, North Sulawesi, Indonesia

Dadan Mohamad Nurjaman, Research Center for Mining Technology, National Research and Innovation Agency (BRIN), KST B.J. Habibie, Puspiptek, Serpong, 15314 Tangerang Selatan, Indonesia
Harmin Sulistiyaning Titah, Department of Environmental Engineering, Faculty of Civil, Planning and Geo-Engineering, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, 60111 Surabaya, IndonesiaFollow
Adji Kawigraha, Research Center for Mining Technology, National Research and Innovation Agency (BRIN), KST B.J. Habibie, Puspiptek, Serpong, 15314 Tangerang Selatan, Indonesia
Ipung Fitri Purwanti, Department of Environmental Engineering, Faculty of Civil, Planning and Geo-Engineering, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, 60111 Surabaya, Indonesia
Wahyu Hidayat, Research Center for Mining Technology, National Research and Innovation Agency (BRIN), KST B.J. Habibie, Puspiptek, Serpong, 15314 Tangerang Selatan, Indonesia

Author ORCID Identifier

Dadan Mohamad Nurjaman: 0009-0008-8137-5088

Harmin Sulistiyaning Titah: 0000-0003-4791-8735

Ipung Fitri Purwanti: 0000-0002-9970-3755

Abstract

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.

Recommended Citation

Nurjaman, Dadan Mohamad; Titah, Harmin Sulistiyaning; Kawigraha, Adji; Purwanti, Ipung Fitri; and Hidayat, Wahyu (2026) "Optimization of cyanide leaching process based on grain size and slurry density in artisanal small-scale gold mining in Tatelu Area, North Sulawesi, Indonesia," Journal of Sustainable Mining: Vol. 25 : Iss. 2 , Article 11.
Available at: https://doi.org/10.46873/2300-3960.1501