Techno-economical evaluation of dewatered stack tailings concept flow sheet options: a case study

Recent tailings storage facility (TSF) failures and the resulting changing legislation requirements to reduce environmental impact and water consumption are placing emphasis on ensuring that the best available technology is applied when designing a tailings management system. This has brought about a need for wider evaluation of tailings dewatering technology approaches. TAKRAF Group was commissioned in July 2023 by Knight Piésold to undertake a conceptual desktop study to evaluate various dewatering tailings technology flow sheets, coupled with materials handling and stacking to the designated dump area, for a copper nickel mine expansion project in Central Africa. This paper focuses on the technology evaluation and methodology applied in the study. It considers capex, installed power, water recovery, metals recovery and process flexibility for a number of processing options. This was done with the emphasis on different filtration and thickening technologies. The paper is limited to the evaluation of the process dewatering technologies and has excluded the tailings storage, transportation and geotechnical drivers in its consideration.