Abstract
Commercial exploitation of the oil sands in northern Alberta in the past 30 years has resulted in the accumulation of almost one billion cubic metres of a clay slurry known as mature fine tailings or MFT. Several technologies are available for the reclamation of the accumulated MFT, and several exist for the prevention of MFT formation. The commercialization of the consolidated tailings or CT process for MFT reclamation and the utilization of thickeners to prevent MFT formation have underscored the importance of understanding clay behaviour in optimizing these processes. This paper discusses the important clay properties that determine the performance of the CT and thickener processes, which are the first steps in the reclamation of the MFT. The variability in clay mineralogy and size distribution in the oil sands is an important factor in determining process performance, as is the process water chemistry. X-ray diffraction and surface-area determinations on the clays, and rheology measurements on the clay slurries, are some of the techniques that enable an understanding of the clay slurry properties that determine oil sands tailings behaviour.
