Oilsands | Pembina Institute

Alberta's Oilsands Climate Impacts Water Impacts Tailings Reclamation Air Pollution


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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
  • For every barrel of bitumen mined from the oilsands, 1.5 barrels of toxic tailings waste is produced.2
Tailings are toxic.
  • Tailings contaminants include naphthenic acids, polycyclic aromatic hydrocarbons, phenolic compounds, ammonia, mercury and other trace metals.3
  • The liquid found in oilsands tailings ponds is acutely toxic to aquatic organisms4,5and mammals.6,7
  • Naphthenic acids are considered to be one of the most significant environmental contaminants resulting from the development of the oilsands,8,9 the effects of which are still largely unknown.10,11
  • The National Pollutant Release Inventory publicly reports the amount of toxic materials disposed in tailings ponds each year. While more than 75 toxic  are tracked, some specific aggregate amounts for 2010 include:12
    • Arsenic: 300,905 kg
    • Benzene: 178,200 kg
    • Lead: 756,793 kg
    • Mercury: 824 kg
    • Toluene: 1,169,000 kg
    • Sum of all PAH compounds: 341,997 kg
  • Between 2006 and 2010, total amount of mercury added to all tailings ponds per year increased by 80%, lead by 50%, and arsenic by 21%.13
Tailings are stored indefinitely in open lakes that cover an area approximately 50% larger than the city of Vancouver.14
  • Tailings lakes occupied 176 square kilometres in 2010.15
  • Tailings are expected to expand nearly 50% in area by 2020 to 250 square kilometres.16
More than 200 million litres of mature fine tailings are produced each day,17 enough to fill Toronto’s Rogers Centre (formerly the Sky Dome) 47 times in a year.18
  • Over 830 million cubic metres of mature fine tailings19  — more than double the volume of water in Alberta's Sylvan Lake — currently require long-term containment.20 The volume of liquid tailings will grow more than 40% from 830 million cubic metres to more than 1.2 billion cubic metres in 2030.21
  • The volume of tailings on the land will continue to grow until 2060 where the volume stabilizes at 1.3 billion cubic metres.22
Tailings lakes seep. The exact amount of seepage is either not known or has not been made public.23
  • Modelled estimates suggest that 11 to 12.6 million litres of tailings leak from tailings ponds each day.24,25
updated April 2013



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