1252 and circular mine waste systems. The following sections review current practice in cold climates, identify limitations and risks under changing weather and climate conditions, and discuss how dry stacking can be aligned with circular economy and low-carbon objectives. 3. STATE OF PRACTICE: DRY STACKING AND WATER-SAVING DEPOSITION IN COLD CLIMATES Water-saving, dry deposition methods have become increasingly common in the mining industry because they reduce water consumption, improve geotechnical stability and lower the risks associated with conventional, water-rich tailings solutions (Sahu et al., 2020; Lottermoser, 2010). In these methods, tailings are placed in the deposition area at relatively low moisture content and compacted mechanically, which reduces pore-water pressure, increases strength and improves long-term stability. These advantages are particularly relevant in cold and northern climates, where freeze–thaw processes, snow accumulation and extreme precipitation events strongly influence the performance of tailings facilities. 3.1 Principles of water-saving dry deposition Dry stacking and other low-water deposition approaches rely on three interlinked pillars: (i) control of moisture content, (ii) adequate compaction and (iii) robust water management (Davies & Rice, 2001). Targeting a relatively narrow moisture window enables mechanical spreading and compaction while limiting frost susceptibility and excess pore pressures. Layered construction and controlled geometry allow operators to build stacks with predictable mechanical behavior and drainage paths. Compared with conventional slurry ponds, these methods reduce the volume of free water stored on the surface and within the voids, thereby lowering the hydraulic load on containment structures and improving the potential for water recycling to the process plant. In cold climates, dry, low-water-content materials often perform better than saturated deposits when exposed to freeze–thaw cycles (Andersland & Ladanyi, 2004; GTK, 2021), because lower pore-water volumes reduce ice lens formation and associated volume changes. However, the effectiveness of dry stacking under these conditions depends strongly on achieving and maintaining the correct moisture content and compaction during placement, as well as providing sufficient drainage capacity to handle snowmelt and intense rainfall. 3.2 Key design parameters and typical ranges in Arctic and sub-Arctic settings Experience from northern operations and the literature indicates that successful dry stacking in Arctic and sub-Arctic environments is governed by a set of key design parameters, summarized conceptually in Table 1 and Table 2. Table 1 – Key Design Principles for Dry Stacking in Cold Climates Parameter Arctic Conditions Subarctic Conditions Moisture High Low Strength Low Moderate - High Climate Dependence High Lower (depending on moisture and compaction control) As shown in Table 1, Arctic conditions are typically characterized by higher moisture contents, lower inherent strength and stronger dependence on climatic factors than sub-Arctic settings. These contrasts illustrate why controlling moisture, strength development and exposure to climate is central to the design of dry-stacked facilities in cold climates. The most critical design parameters are discussed in more detail below.
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