GeoStable Tailings laboratory mixture trial

Abstract

This study focused on GeoStable Tailings, a homogeneous mixture of tailings and waste rock. The research evaluated (i) the influence of laboratory placement methods on mixture dry density and (ii) the influence of mixture characteristics (mixture ratio and tailings solids content) on hydraulic and mechanical behavior of GeoStable Tailings. Laboratory testing was conducted to assess dry density, air permeability, penetration resistance, and slump for different GeoStable Tailings mixture ratios, tailings compositions, solids contents, and placement methods. Standard Proctor compaction, drop chute, and loose placement methods were used to represent a range of compaction energies. Placement of GeoStable Tailings with standard Proctor compaction yielded specimens that were more consistent in the engineering behavior, whereas specimens placed via the drop chute or loose placement were more variable. Results indicate that standard Proctor compaction produces more consistent engineering behavior, whereas drop chute and loose placement exhibit greater variability. Whole tailings with solids contents above 80% and mixture ratios between 1.0 and 2.0 demonstrated optimal performance in minimizing air permeability, ensuring trafficability, and maintaining structural integrity. Underflow tailings exhibited a broader range of viable mixture ratios and solids contents, with enhanced stability and reduced deformation potential. Findings from this research contribute to the development of practical design guidelines for field applications of GeoStable Tailings, supporting the integration of tailings and waste rock as a sustainable alternative to traditional tailings management.