883 KEY DESIGN CONSIDERATIONS FOR TAILINGS DEWATERING Integrating tailings properties with unsaturated soil mechanics for safe, efficient filtered tailings stacking. Ljiljana Josic Senior Director, Global Capabilities, Tailings, Water and Geotechnical Engineering, AtkinsRéalis ABSTRACT With the increasing demand for minerals worldwide, tailings production is on an increasing trend. It has been estimated that nickel, lithium, and cobalt production need to increase by 150% to supply the electric vehicle and clean energy sector in the coming years. This significant increase in metals production will result in a corresponding substantial increase in tailings production and the need for proper management. There is a need to restore trust and confidence in the industry’s ability to safely manage tailings, as the current rate of tailings failures is unacceptable to society and industry. The analysis focuses on the adoption of various tailings dewatering techniques within the mining industry, highlighting the proportion of mines currently using or planning to implement such methods. There is increasing awareness of the advantages of dewatering, alongside a growing emphasis on socioeconomic factors, which position filtered tailings as more beneficial than traditional tailings facilities. A rising number of projects are evaluating potential risks and additional benefits related to reputation, sustainability, and responsible mining practices, thereby enhancing the likelihood of embracing dewatering technologies. Furthermore, social pressures and regulatory requirements are poised to escalate the costs associated with conventional management while also compelling a reduction in water consumption, lowering the risk of tailings dam failures, and fostering demand for progressive reclamation. These elements continue to favor the implementation of tailings dewatering technologies over conventional tailings storage solutions. This paper summarizes key design considerations for the tailings dewatering. KEYWORDS Tailings; Dewatering; Filtered Tailings; Unsaturated Soil Mechanics; Geotechnical Design CONTEXT AND PROBLEM STATEMENT The mining industry produces 80–90 billion tonnes of waste rock and roughly 8 billion tonnes of tailings annually. As ore grades decline, waste volumes increase, intensifying risk and societal scrutiny. Dewatering tailings to produce a trafficable filter cake for filtered tailings stacking is increasingly evaluated to enhance safety and reduce water use. However, realizing these benefits depends on rigorous geotechnical design and operational discipline under unsaturated conditions. A growing body of global guidance recognizes that one of the significant barriers to the reliable implementation of filtered tailings systems is the insufficient understanding of the geotechnical behavior of filtered tailings under operational and long-term conditions. Filtered tailings, by definition, operate in the unsaturated domain, where matric suction, compaction state, moisture variability, and hydraulic conductivity interact in ways fundamentally different from conventional saturated tailings. Unlike slurry-disposed tailings, filtered tailings behave more like an engineered soil, requiring a deeper understanding of soil mechanics, particularly unsaturated soil mechanics, to predict how strength, stiffness, and permeability evolve under deposition, loading, and climatic fluctuations. Figure 1 presents a global comparison of conventional versus filtered tailings storage facilities derived from the Global Tailings Portal (GRID-Arendal, 2021). The dataset comprises 2,056 facilities disclosed by mining companies and provides insight into the distribution of tailings management technologies worldwide. The results clearly indicate that while filtered tailings are increasingly recognized
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