Filtered Tailings as an Enabler of Co-Disposal Filtered tailings play a crucial role in modern co-disposal strategies. Their low moisture content and controlled grain size distribution provide a stable fine fraction that mixes well with coarse materials. Moisture Control and Blendability The (Palmer et al.) study establishes a strong relationship between cake moisture content and blendability, identifying an optimal moisture level near 95% of Proctor optimum (~16% moisture). At this condition: • the tailings cake fragments less, • maintains cohesiveness, • mixes more uniformly with aggregates, and • yields more stable co-disposal mixtures. Higher moisture leads to plasticity, instability, and poor mixing behaviour, while too-dry cake becomes brittle and loses cohesion. Maintaining consistent moisture—enabled by modern automated filtration—is therefore essential for effective co-disposal. Filter Cake as a Fine Fraction for Geotechnical Improvement Filtered cake, when well-controlled, serves as an ideal fine material to fill voids in waste rock. Previous studies demonstrate: • improved structural stability at various blend ratios, • reduced compaction effort required during placement, • minimized transport and spreading challenges, and • better long-term deposit performance. These advantages make filtered tailings uniquely suited for hybrid waste storage designs. Co-Disposal Approaches and Engineering Considerations Several co-disposal strategies appear in the documents: Co-Mixing (Engineered Backfill or Above-Ground Stacks) This involves blending waste rock and filtered tailings in controlled ratios such as 20:1, 5:1, or 1:1, as tested in the CONCEPTS FOR CO-MIXING study. In these trials: • hydraulic conductivity decreased dramatically, particularly when bentonite or compaction was added, • shear strength improved due to coarser rock fractions, and • controlled compaction increased stability. These enhanced geotechnical and hydraulic characteristics support safer and more resilient landforms. Co-Disposal in Waste Rock Dumps Co-disposal can also be implemented by strategically incorporating filtered tailings into waste rock dumps, reducing:
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