Oil Sands Watch | Pembina Institute
 

Tailings

Tailings are a waste byproduct from the oil sands extraction processes used in mining operations.
  • Tailings consist of a mix of water, sand, silt, clay, contaminants and unrecovered hydrocarbons.1
Tailings are toxic.
  • Tailings contaminants include naphthenic acids, polycyclic aromatic hydrocarbons, phenolic compounds, ammonia, mercury and other trace metals.2
  • The water found in oil sands tailings ponds is acutely toxic to aquatic organisms3 and mammals.4
According to the International Agency for Research on Cancer, the National Toxicology Program and the U.S. Environmental Protection Agency, certain polycyclic aromatic hydrocarbons have been classified as definite, probable or possible cancer-causing agents.
  • Naphthenic acids are considered to be the most significant environmental contaminant resulting from the development of the oil sands.5
Tailings stored indefinitely in open lakes that cover an area larger than the city of Vancouver.6
  • Tailings lakes currently occupy 130 square kilometres.7
  • Tailings are expected to more than double in size by 2040 to occupy an area of 310 square kilometres.8
Tailings lakes increase in volume at a rate that would fill 80 Olympic-sized swimming pools each day.9
  • After process waters are removed and recycled, an average of 1.5 barrels of mature fine tailings accumulate for every barrel of bitumen produced.10 At this rate, 200 million litres of mature fine tailings are produced each day.11
  • As of June 2008, 720 billion litres of mature fine tailings — nearly double the volume of water in Alberta’s Sylvan Lake — required long-term containment.12
Tailings lakes leak. The exact amount of leakage is either not known or has not been made public.13
  • Modelled estimates suggest that as much as 4 billion litres of tailings leak from tailings ponds each year.14

 

  1. 1. M. D. MacKinnon et al., “Water Quality Issues Associated with Composite Tailings (CT) Technology for Managing Oil Sands Tailings,” International Journal of Surface Mining, Reclamation and Environment 15, no. 4 (2001).
  2. 2. P. G. Nix and R. W. Martin, “Detoxification and Reclamation of Suncor’s Oil Sand Tailings Ponds,” Environmental Toxicology and Water Quality 7, no. 2 (1992).
  3. 3. M. D. MacKinnon and H. Boerger, “Description of two treatment methods for detoxifying oil sands tailings pond water,” Water Pollution Research Journal of Canada 21 (1986): 496–512.
  4. 4. U.S. Environmental Protection Agency, Office of Toxic Substances, “Fate and Effects of Sediment-bound Chemicals in Aquatic Systems,” Proceedings of the Sixth Pellston Workshop, Florissant, CO, August 12–17, 1984.
  5. 5. V. V. Rogers et al., “Acute and Subchronic Mammalian Toxicity of Naphthenic Acids from Oil Sands Tailings,” Toxicological Sciences 66 (2002).
  6. 6. The City of Vancouver is 114.7 square kilometres in area (NationMaster - Encyclopedia - Vancouver, British Columbia).
  7. 7. Alberta Environment, “Tailings” (accessed May 1, 2009).
  8. 8. Energy Resources Conservation Board, “Data for Mineable Oil Sands Current and Projected Tailings and Footprint Area,” email received October 2008.
  9. 9. An Olympic-sized swimming pool holds roughly 2,500 cubic meters of water.
  10. 10. R. J. Mikula, V. A. Munoz and O. Omotoso, “Water Use in Bitumen Production: Tailings Management in Surface Mined Oil Sands,” presented at the World Heavy Oil Congress (Edmonton, AB: 2008).
  11. 11. Calculated based on the production of 1.5 barrels of mature fine tailings per barrel of bitumen (R. J. Mikula, V. A. Munoz and O. Omotoso, “Water Use in Bitumen Production: Tailings Management in Surface Mined Oil Sands,” presented at the World Heavy Oil Congress, Edmonton, AB:, 2008) and the production of 841,000 barrels of bitumen per day (Energy Resources Conservation Board, “Alberta’s Energy Reserves 2007 and Supply/Demand Outlook 2008–2017,” Figure 2.12).
  12. 12. Alberta Energy Resources Conservation Board, “ERCB releases draft directive on oil sands tailings management and enforcement criteria,” news release, June 26, 2008. Sylvan Lake has a volume of cubic metres (Patricia Mitchell, Assessment of Water Quality in Sylvan Lake [Alberta Environment, Water Sciences Branch, 1999], 5).
  13. 13. M. Price, 11 Million Litres a Day: The Tar Sands’ Leaking Legacy (Toronto, ON: Environmental Defence, 2008), (accessed December 10, 2008).
  14. 14. M. Price, 11 Million Litres a Day: The Tar Sands’ Leaking Legacy (Toronto, ON: Environmental Defence, 2008), (accessed December 10, 2008).