1254 3.3 Stability-control factors and operational practice The stability of dry-stacked tailings in cold climates is governed by several interacting factors (Andersland & Ladanyi, 2004; GTK, 2021), which can be grouped as shown in Table 3. Table 3 – Factors Affecting Dry Stack Stability Factor Description Moisture Content Typical target range: 8 – 12 %. Enables adequate compaction and reduces frost susceptibility. Compaction High compaction maintains strength, reduces settlement, and improves frost resistance. Water Management Essential for managing snowmelt, heavy rainfall, and seasonal runoff. Freeze – Thaw Processes May alter permeability, density, and pore structure, especially in fine-grained materials. Dust Control Dry materials are prone to wind erosion, a significant challenge in open northern environments. Together, the factors listed in Table 3 highlight that dry stack stability in cold climates is not controlled by a single variable, but by the combined effects of moisture, compaction, drainage conditions and climate-driven processes. Each factor must be managed within an appropriate operating window, and small deviations can interact in non-linear ways over time. The most critical aspects are discussed in more detail below. • Moisture and compaction: Moisture content and compaction are primary controls on density, strength and frost susceptibility. High compaction levels help maintain material strength and limit long-term settlement, while appropriate moisture reduces the risk of ice lens formation and differential heave. Achieving these targets in practice requires continuous monitoring of tailings moisture at the filter, on the stack and during compaction, as well as flexible operating procedures to adjust deposition when weather conditions change. • Water management: Effective water management is essential, particularly during snowmelt and heavy rainfall events. Surface drainage structures, internal drainage layers and diversion channels must be designed to prevent ponding, minimize infiltration into the stack and avoid local increases in pore pressure. In Arctic settings, the timing and intensity of meltwater peaks can be highly variable, making it necessary to account for extreme scenarios and climate change projections in the design of drainage capacity.
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