Tailings are a by-product of the process used to extract bitumen from mined oil sands and consist of water, silt, sand, clay and residual bitumen.
Tailings are deposited in man-made tailings ponds surrounded by collection and monitoring systems.
When a mine begins operation, tailings are deposited into above-ground man-made structures called tailings ponds. Once a mined-out pit becomes available, tailings are stored there.
Tailings ponds are essential to oil sands mining operations as they act both as holding areas, where the majority of the water needed for bitumen extraction can be recycled, and as settling basins for solids.
See Oil Sands > Mining Impacts for more information.