The study shows that: high water-demand systems (slurry deposition) increase lifetime energy costs, thicker or filtered tailings reduce both water demand and pumping energy, filtered tailings, while energy-intensive at the filtration stage, reduce energy at the TSF because they eliminate hydraulic pumping of high-yield-stress slurries and instead rely on conveyors or trucking. This aligns with findings from the (Carneiro & Fourie 2019) life-cycle cost studies, which show that the energy cost of pumping slurry via centrifugal pumps can significantly exceed that of transporting high-density or filtered tailings, especially as solids concentration increases. Thus, when water and energy are evaluated together—as they must be—the attractiveness of filtered tailings improves substantially. Water Efficiency of Dewatered Tailings Technologies Thickened and Paste Tailings Thickened and paste technologies reduce free water and improve water return to the plant, but they still retain significantly more water than filtered tailings. Araya et al. confirm that while they reduce water consumption compared with slurry, they remain more energy-demanding in pumping and generate higher yield stresses, which limits transport flexibility. Filtered Tailings Filtered tailings recover the highest proportion of process water, driven by mechanical dewatering rather than gravity. The How to Make Filtered Tailings Feasible report notes that modern pressure filters achieve very low moisture content—down to ~5% in some applications—returning nearly all liberated water back to the concentrator. • Dry-stack systems therefore produce: • materially lower water losses to seepage, evaporation, and entrainment, • reduced need for raw or desalinated water, • enhanced water security in arid or drought-prone environments. In jurisdictions with increasingly stringent water rights allocations, such as Chile, these benefits are becoming decisive factors in regulatory approvals. Water Management and Hydrological Stability in Filtered TSFs Filtered tailings reduce the hydrological complexity of the tailings facility by minimizing free water. However, engineered water management remains essential. The (Vargas & Campomanes Minerals 2022) review outlines several key design elements required for hydrological stability: • Spillage retention dams to capture runoff from extreme rainfall events, • Underdrainage systems to intercept and collect seepage through the base of the stack, • Seepage collection sumps to prevent uncontrolled releases, lined with geomembrane systems, • Progressive cover placement to control dust and erosion, and to facilitate vegetation. These systems ensure that filtered stacks operate with very low seepage rates, reducing groundwater contamination risks and supporting long-term environmental resilience.
RkJQdWJsaXNoZXIy MTM0Mzk2