Stability of copper mine tailings dam for upstream, downstream and centre-line construction methods: numerical analysis

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4. Stability of copper mine tailings dam for upstream, downstream and centre-line construction methods: numerical analysis

Over the past few years, there have been numerous catastrophic tailings dam failures documented globally. In this study, the stability analysis of a copper mine tailings dam constructed by upstream (USM), downstream (DSM) and centreline (CSM) method was evaluated for static conditions by using finite element analysis. The developed numerical model was validated with the reported literature and it showed good agreement. The optimal combination between the height and slope of the tailings dam were investigated in terms of factor of safety and the failure planes were determined. The stability analysis was performed at each stage of construction of tailings dam. In order to enhance the stability of the tailings dam, several geogrid layers with varying vertical spacing between the layers were used. The optimum length of reinforcement was at a length to base width ratio of 1.3. Results revealed that the laying length and vertical spacing of the geogrid are the prime factors affecting the stability of tailings dam, whereas the stiffness of geogrid does not considerably affect the stability. It was also observed that the sequential construction of upstream method has high excess pore water pressure in comparison to other methods. The seismic resistance of the tailings dam was also evaluated. It was observed that the upstream method of construction was more susceptible to seismic conditions. The factor of safety decreased by about 15%, 13%, and 11% in the case of USM, DSM, and CSM, respectively, when horizontal seismic coefficient increased from 0.06g to 0.10g.

9th International Congress on Environmental Geotechnics (ICEG2023)

Resource Mining and Extraction