Hydrogeochemical Modeling of Mineral Processes in Hot Springs and Mine Waters

Understanding hydrogeochemical processes is essential for predicting mineral alteration and carbonate scaling in geothermal and mining environments.However, such studies remain limited in Malifut, North Maluku, where geothermal manifestations and mining activities coexist.This study aims to classify hydrochemical facies and evaluate mineral stability in various thermal waters, including underground mine waters, a hot spring, and borehole thermal waters.Field measurements of temperature, pH, electrical conductivity, and total dissolved solids were conducted, while major ions were analyzed using ion chromatography.Hydrochemical facies were identified using the Cl-SO-HCO ternary diagram, and mineral saturation indices were modeled with PHREEQC.The classification revealed that borehole waters belong to the peripheral type, while Shallut and Kencana mine waters are steam-heated, and Toguraci, together with Akesahu hot spring, are volcanic waters.PHREEQC modeling revealed that volcanic and steam-heated waters are oversaturated with calcite and aragonite, indicating a strong potential for carbonate precipitation due to CO degassing and elevated temperatures.Borehole waters were mostly near equilibrium or undersaturated, except PZ-8, which exhibited dolomite oversaturation and a clear geothermal signature.All samples were undersaturated with gypsum and anhydrite, indicating carbonate equilibria as the dominant control.This integrated approach enhances the understanding of water-rock interaction, fluid origin, and scaling risk in geothermal-mining systems, and provides practical insights for water management and scaling mitigation strategies in Malifut.