A review of properties and treatment of oil sands tailings

The hot water process used to extract bitumen from the oil sands in northern Alberta produce an alkaline tailings stream containing sand, clays, residual bitumen, and small amounts of soluble organic compounds. The suspension formed by the fine clay minerals has proven to be resistant to consolidation, leaving a growing pool of persistent sludge in large tailings ponds. An introduction is provided to the literature that exists in the area of oil sand tailings characterization and treatment. Studies on the chemical, physical, and microbiological makeup of oil sands tailings and the tailings ponds are described, including settling and consolidation behavior of solids in tailings ponds and various theories as to why tailings pond sludge is so resistant to consolidation. Studies undertaken to reduce the tailings problem are reviewed, including investigation of reclamation methods for the mine site, and chemical, physical, geotechnical and biotechnical approaches to tailings treatment. Finally, there is a brief discussion of tailings problems in other industries and the methods used to try to alleviate those problems. 275 refs., 5 figs., 12 tabs.