Assessing Oil Sands Tailings Consolidation Parameters Relative to Long-term Reclamation

The reclamation of tailings deposits is dependent upon long-term consolidation, which determines both the final storage volume and ultimate deposit strength. Very soft materials like flocculated mature fine tailings undergo large deformations during consolidation. Describing this “large strain consolidation” requires non-linear equations for compressibility and hydraulic conductivity as functions of void ratio or effective stress. Typically, these equations are input to a finite strain consolidation model to estimate overall consolidation rates. This paper presents a robust sensitivity analysis to examine the effects of material property functions and design variables on consolidation model results. The tested variables included compressibility constants, hydraulic conductivity constants, years of deposition, rate of rise, specific gravity, initial solids content, and surcharge load application. Interpretation of the results identified clear patterns and dimensionless groupings that can be used as indicators of ultimate consolidation performance.