Geotechnical Study for Hydraulic Barrier System at Tailings Pond

Lead–zinc tailings fall under the category of hazardous waste as per the “Hazardous Waste Management And Handling Rules” notification in India. Groundwater protection measures are to be adopted for an unlined tailings pond in which such tailings are being disposed. This paper presents the process of selection of an appropriate hydraulic barrier system for the tailings pond through field and laboratory based geotechnical investigations. Results of subsurface site investigations are presented. Two hydraulic barrier systems are compared—one in the form of an intermediate liner system (horizontal) and the other, a vertical cutoff system. The relative advantages and costs associated with both systems are evaluated. The study shows that the vertical cutoff system is more cost effective and advantageous for the tailings pond because of the presence of sound rock at shallow depth. The design of backfill material for the cutoff wall, using bentonite as an additive, is highlighted.