1257 reduce the demand on freshwater sources and receiving water bodies. In addition to water, dewatering circuits and warm tailings streams carry sensible heat that could in principle be recovered. Heat exchangers or heat-pump systems coupled to warm process water or tailings filtrate may support low-temperature district heating, mine ventilation air heating or other on-site uses, especially in regions with long heating seasons. Although practical implementations remain limited, the combination of high water-recovery rates and potential heat utilization positions dry stacking as part of a broader strategy to optimize both water and energy use along the mine-to-mill pathway. 5.2 Tailings as a resource in circular economy Circular economy strategies increasingly emphasize the valorization of mining wastes as secondary resources. Controlled, relatively homogeneous dry stacks can facilitate future access to tailings volumes, reducing the cost and complexity of re-mining or reprocessing compared with submerged or unconsolidated slurry ponds. Tailings have been investigated as sources of critical and battery minerals, as feedstock for geopolymers and ceramics, and as constituents in construction materials such as masonry units, road bases and backfill (Lottermoser, 2010; Kossoff et al., 2014). From a circularity perspective, dry stacking offers several advantages. First, higher water-recovery and improved geotechnical stability reduce the environmental liabilities associated with long-term pond management, which can otherwise limit the feasibility of future reprocessing (UNEP, 2019). Second, the ability to build engineered, accessible landforms supports staged reclamation, integration of re-use projects and potential co-location with other industrial activities. However, moving from conceptual potential to large-scale implementation requires addressing regulatory acceptance, material qualification standards and economic trade-offs between immediate disposal costs and long-term recovery options. 5.3 Life cycle and low-carbon opportunities The sustainability benefits of dry stacking must be evaluated in a life cycle perspective, balancing additional energy use in filtration and transport against reduced water consumption, lower failure risk and circularity gains. Life cycle assessment (LCA) following ISO 14040, combined with databases such as Ecoinvent (Ecoinvent Association, 2023), provides a structured way to compare conventional slurry ponds, thickened and paste tailings, and filtered dry stacks under different climatic and operational conditions. Preliminary LCA work and near-zero-waste studies suggest that, when designed appropriately, dry stacking can contribute to lower overall environmental impacts by reducing seepage and catastrophic failure risk (Sahu et al., 2020; SYKE, 2022), enabling reuse of tailings in products and lowering long-term water and land footprints. At the same time, filtration energy, additional equipment and possible heating requirements in cold climates can increase operational emissions. Integrating climate-scenario analysis, hydrological modeling and LCA as proposed in ongoing research on northern dry stacking offers a pathway to quantify these trade-offs and to identify design configurations that are both climate-resilient and compatible with carbon-neutral mining targets. 6. REQUIREMENTS AND RESEARCH AGENDA FOR CLIMATE-RESILIENT DRY STACKING The previous sections have shown that the performance of dry-stacked tailings in Arctic and subArctic environments depends on a tight interplay between material properties, climate, dewatering technology and operational practice. To move from promising case studies to robust, climate-resilient deployment at scale, a set of design and research requirements must be addressed in an integrated way. 6.1 Design principles for climate-resilient dry stacking Climate-resilient dry stacking in northern conditions requires going beyond a “static design” approach and instead adopting adaptive design principles that explicitly account for variability and change in weather and climate (Tuomela, 2022; Andersland & Ladanyi, 2004). Key elements include:
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