A Metal Sorption/Desorption Study to Assess the Potential Efficiency of a Tailings Dam at the Golgohar Iron Ore Mine, Iran

The Golgohar Iron Ore Mine in southern Iran is a large open pit that operates below the groundwater table; until now, its tailings have been disposed of without proper environmental safeguards. A tailings dam, constructed with environmental standards, has been proposed to address this problem. So, it was important to assess the effect of the solid and liquid wastes on the sorption/desorption behavior of the soil of the site to evaluate the risk of release of metal contaminants to groundwater after dam construction. Soil samples from a proposed tailings dam reservoir site and dried solid waste from the present tailings dump were collected for analysis to assess the potential effects of solid and liquid wastes on the sorption/desorption behavior of the soil and the risk of resultant groundwater contamination after dam construction. Laboratory batch and sorption isotherm tests along with a pilot-scale field experiment were conducted to study the sorption potential of the soil. Analysis showed that concentrations of Co, Ni, Cu, As, Sr, and Mn in the soils were already significantly elevated. The experiments indicated that although the soil of the area has some potential to adsorb contaminants such as Co, Ni, Cu, and As, other elements, such as Sr and Mn will be more mobile. Given the soil's limited sorption capacity, these contaminants will all likely enter the groundwater eventually, and so the probable transmission of these elements into the lower depths must be considered in the design of the proposed dam.