Geotechnical properties of polymer-amended tailings solvent recovery unit (TSRU) oil sands tailings

Abstract

Fine tailings from the tailings solvent recovery unit (TSRU) in the Athabasca oil sands are known to contain a relatively high pyrite content and a high residual hydrocarbon content, which may alter their geotechnical properties. Little is known about TSRU tailings properties and therefore the potential for subaerial deposition. The goal of this study was to investigate the geotechnical properties of untreated, polymer-amended, and sand-mixed TSRU tailings to provide information for the consideration of subaerial deposition and increase the general knowledge about these unique tailings. The polymer-amended tailings had more desirable properties for subaerial deposition, including a lower final void ratio, less energy required to desaturate, and higher compressibility, when compared with the untreated tailings. The sand-mixed samples enhanced these properties, but may pose issues for transportation. The mineralogy indicated that the polymer-amended TSRU tailings have a high-enough pyrite content for acid generation, which may pose environmental issues for subaerial deposition. Overall, TSRU tailings exhibited different geotechnical properties when compared with the well-studied mature fine tailings, highlighting the need for further studies to provide information for the management of TSRU tailings.