The Oil sands tailings ponds are settling ponds that contain the waste byproduct of oil sands extraction and upgrading. They are a mix of water, sand, silt, clay, unrecovered hydrocarbons, and other contaminants. The management of tailings ponds is one of the most difficult environmental challenges associated with oil sands and their existence is extremely controversial. Currently, tailings ponds occupy a fair amount of space in Alberta—covering around 77 square kilometers. Including all tailings ponds structures along with the ponds themselves, the total covered area is 220 square kilometers—an area about 1.5 times larger than the city of Vancouver (about 176 square kilometers as of 2010).
There are several environmental concerns that are associated with the existence of tailings ponds. The main problem with the ponds is that they include toxic and harmful chemicals such as ammonia, mercury, and naphthenic acids. The water containing these chemicals is toxic to animals, particularly aquatic organisms. If aquatic organisms enter these ponds, significant levels of damage can occur. In addition, these ponds are not sealed tightly. Instead, the water and contaminants from the pond seep into the soil surrounding it, potentially contaminating groundwater and harming wildlife surrounding the pond. As well, these ponds exist almost indefinitely, with over 830 million cubic meters requiring long term containment. This poses a risk to wildlife, mainly birds, who can be harmed if they come into contact with the water in these ponds.
Another concern about the use of tailings ponds is the volume of oil sands tailings produced from bitumen extraction. For every barrel of bitumen extracted from the oil sands, 1.5 barrels of tailings waste is produced. This large volume of tailings requires a large area for storage, and the sheer size of tailings ponds can be an issue, as they encroach on wildlife territory.
Efforts are being made to reduce the impact that tailings ponds have on the environment. First, bird deterrence systems have been created and used to prevent birds from landing on the ponds. These air cannons are used to frighten away the birds if they get too close. Targets have also been set for companies to reduce tailings and provide specific dates for when the ponds will be closed and reclaimed. In addition, timelines are being created that requires that fluid tailings be processed as quickly as they are being created, preventing tailings growth.
It can be difficult to comprehend the amount of area that tailings ponds take up. Below is a labelled, interactive map showing the mining pits, tailings ponds, some reclaimed area, and the Athabasca river. Take a note of the scale on the bottom right-hand side of the map (this will change when zooming in and out, but gives an idea of the size of mines and tailings ponds).