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Oilsands | Pembina Institute
 
Alberta's Oilsands Climate Impacts Water Impacts Tailings Reclamation Air Pollution

Tailings

Tailings are a waste byproduct from the oilsands 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 liquid found in oilsands tailings ponds is acutely toxic to aquatic organisms3 and mammals.4
  • Naphthenic acids are considered to be one of the most significant environmental contaminants resulting from the development of the oilsands,5 the effects of which are still largely unknown.6 ,7
  • In 2009, data on the concentrations of toxic materials found in all oilsands tailings ponds were publically released for the first time. While more than 75 toxic substances were tracked, some specific aggregate volumes included8:
    • Arsenic: 31,305 kg
    • Benzene: 162,000 kg
    • Lead: 651,875 kg
    • Mercury: 747 kg
    • Sum of all PAH compounds: 218,456 kg
  • Between 2006 and 2009, total levels of mercury across all tailings ponds increased by 63%, lead by 29%, and arsenic by 28%. Asbestos topped the volume growth rates, with a 949% increase over the same four year period.9
Tailings are stored indefinitely in open lakes that cover an area approximately 50% larger than the city of Vancouver.10
  • Tailings lakes currently occupy 170 square kilometres.11
  • Tailings are expected to expand nearly 50% in size by 2020, to occupy an area of 250 square kilometres.12
Tailings lakes increase in volume at a rate that would fill the Toronto Skydome on a daily basis.13
  • After process waters are removed and recycled, an average of 1.5 barrels of mature fine tailings accumulate for every barrel of bitumen produced through mining.14 At this rate, nearly200 million litres of mature fine tailings are produced each day.15
  •  Over 843 million cubic metres of mature fine tailings - more than double the volume of water in Alberta's Sylvan Lake - currently require long-term containment.16 The volume of liquid tailings will grow 30% from 843 million cubic metres to more than 1.1 billion cubic metres in 2020.17
Tailings lakes seep. The exact amount of seepage is either not known or has not been made public.18
  • Modelled estimates suggest that 11 to 12.6 million litres of tailings leak from tailings ponds each day.19

 

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. 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. 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. 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. V. V. Rogers et al., "Acute and Subchronic Mammalian Toxicity of Naphthenic Acids from Oil Sands Tailings," Toxicological Sciences 66 (2002).

6. Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry (2010) (accessed January 28, 2011).

7. Scott, A. C., W. Zubot, M. D. MacKinnon, D. W. Smith, and P. M. Fedorak, "Ozonation of oil sands process water removes naphthenic acids and toxicity" in Chemosphere 71: 156-160.

8. Compiled from the National Pollutant Release Online Inventory. Volumes include reported data from CNRL Horizon, Syncrude Mildred, Syncrude Aurora, Shell Muskeg River and Suncor Mine.

9. Compiled from the National Pollutant Release Online Inventory. Volumes include reported data from CNRL Horizon, Syncrude Mildred, Syncrude Aurora, Shell Muskeg River and Suncor Mine.

10. The City of Vancouver is 114.7 square kilometres in area (NationMaster - Encyclopedia - Vancouver, British Columbia ).

11. Government of Alberta. "ERCB Approves Fort Hills and Syncrude Pond Plans with Conditions," media release, April 23, 2010 (accessed December 22, 2010).

12. The Pembina Institute and Water Matter, Tailings Plan Review (accessed December 22, 2010).

13. The Toronto Skydome has a volume of 1.6 billion litres whereas toxic tailings waste is produced at a rate of 1.8 billion litres per day. This is the gross volume pre-recycling. Jennifer Grant, Simon Dyer, and Dan Woynillowicz, Fact or Fiction: Oilsands Reclamation (The Pembina Institute, 2008) (accessed January 31, 2011).

14. 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).

15. 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) and the production of 830,000 barrels of bitumen per day (Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry).

16. Sylvan Lake has a volume of 412 million cubic metres (Patricia Mitchell, Assessment of Water Quality in Sylvan Lake (Alberta Environment, Water Sciences Branch, 1999), 5).

17. Calculations completed by the Pembina Institute and Water Matters based on data from company submissions to the ERCB. See Jennifer Grant, Simon Dyer, Nathan Lemphers and Jennifer Dagg, Northern Lifeblood, (The Pembina Institute, 2010).

18. Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry.

19. M. Price, 11 Million Litres a Day: The Tar Sands' Leaking Legacy (Environmental Defence, 2008), (accessed December 10, 2008).
Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry.

updated March 2011