Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

The subsurface dispersion of As and heavy metals from mine tailings was investigated, and containment system design for the reclamation was also examined to manage various mine wastes. Surface tailings of the abandoned Kubong Au-Ag mine were enriched in As, Cd and Pb, and their mean concentrations extracted by aqua regia were 5,040, 54 and 2,800 mg/kg, respectively. Vertical profiles of As and heavy metals from the analysis of core samples of the tailings pile indicated gradual decrease below the tailings layer. However, heavy metals were accumulated just below the boundary of tailings and lower soils, and significant amounts of As up to 679 mg/kg were found at more than 10 m depth. Dilute acid-extractable fractions of As by 0.5N HCl-leaching were also increased below the tailings layer, and it is suggested that As and heavy metals were leached from the tailings pile and then accumulated in deeper alluvial soils by adsorption/precipitation on oxide and clay minerals. Containment model was modified with a funnel (impermeable barrier) and gate (reactive zone) system to manage the mine wastes, and subsurface release of contaminants can be controlled, provided that efficient reactive materials are applied. Iron-raw ore product and limestone as reactive materials required more reaction time to treat As in leachate by complexation and Ca-arsenate formation.