Evaluation of Leakage Potential from Tailing Dam of Sungun Copper Mine Using Hydrogeological Findings and Numerical Modelling

Abstract

 This research predicted the hydraulic behaviour of the Sungun copper mine tailings dam (NW Iran) in the reservoir's final height and introduced the best sealing to prevent downstream leakage. 14 locations upstream and downstream and several boreholes in dam abutments were sampled. PLAXIS numerical modelling predicted the dam's hydraulic behaviour and sealing procedures for various leakage scenarios. For each abutment of the dam, simulation scenarios have been considered, including simulation in the current and final height of the tailings. Suspended injection curtain and full injection curtain in two different positions were studied, as well. Results showed no pollution leakage at the current level of tailings. The PLAXIS model also predicts a reservoir tailings leakage at the final height. Then, the rise in hydraulic head would induce pollution discharge in the downstream areas. With the assumption that the concentration of elements in the effluent from the tailings dam would remain constant, 41 kg per year of heavy elements will flow the downstream waters. It was determined that a full injection curtain with a height of 200 meter, a width of 3 meters and a permeability of 10-8 m/s, near the dam axis had the least amount of leakage (0.13 L/s) in the final level (125 meter) of the left abutment. Then, the PLAXIS model was utilized for the right abutment, which, in the current level, allows leakage (0.06 L/s) and also in the final level (0.18 L/s); thus, the implementation of the injection curtain in the right abutment is not advised.