Abstract

As the global demand for metals increases to support the transition to cleaner energies, the mining industry looks to large low-grade porphyry deposits to meet the rising demand which generates large tonnages of tailings solids at high rates to maintain project economics. Cycloning the tailings solids to produce sand for embankment fill is a common methodology to achieve project economics; embankment construction involves hydraulically placing a cycloned sand slurry within the embankment shell and allowing it to drain. Hydraulic cell placement (i.e., horizontal cells with decant pipes and sedimentation ponds) is usually prescribed to achieve specific density targets for structural stability but must be balanced by constructability and water management considerations. Conversely, cycloned sand slurry can be placed hydraulically in a top-down fashion from embankment crests to reduce water usage by conveying the sand slurry at higher solids contents and create a non-segregating material when placed on the embankment shell. This methodology alleviates the need for large sediment and water management infrastructure at the toe of the embankment which present their own operations and maintenance challenges. This presentation will explore the advantages and disadvantages of top-down versus hydraulic cell construction practices and provide insight in the design and operational controls required to manage a top-down cycloned sand operation.