page_title: Oil sands tailings ponds (Canada)
section_title: Syncrude Tailings Dam
hierarchical_section_title: Oil sands tailings ponds (Canada) / Cost of clean-up / Syncrude Tailings Dam
caption_attribution_description: English: This is a picture of Syncrude's base mine. The yellow structures are the bases of pyramids made of sulphur - it is not economical for Syncrude to sell the sulphur so it stockpiles it instead. Behind that is the tailings pond, held in by what is recognized as the largest dam in the world. The extraction plant is just to the right of this photograph and most of the mine is to the left. Deutsch: Tagebau der Syncrude Canada Ltd. zur Gewinnung der Athabasca-Ölsande im Nordosten von Alberta, Kanada. Die gelben Gebilde sind Schwefelhalden. Der Schwefel entstammt dem im Ölsand enthaltenen Asphalt und wird dort gelagert, weil es unwirtschaftlich ist, ihn zu verkaufen. Dahinter befindet sich ein Absetzbecken für Schlämme aus der Ölsandaufbereitung (engl.: tailings pond). Das Werk, in dem die Extraktion des Asphalts stattfindet, ist unmittelbar rechts außerhalb des Bildes, während sich der größte Teil des Tagebaus links außerhalb des Bildes befindet.
context_page_description: Oil sands tailings ponds are engineered dam and dyke systems used to capture oil sand tailings. Oil sand tailings contain a mixture of salts, suspended solids and other dissolvable chemical compounds such as acids, benzene, hydrocarbons residual bitumen, fine silts and water. Large volumes of tailings are a byproduct of bitumen extraction from the oil sands and managing these tailings is one of the most difficult environmental challenges facing the oil sands industry.
context_section_description: The Syncrude Tailings Dam or Mildred Lake Settling Basin (MLSB) is an embankment dam that is, by volume of construction material, the largest earth structure in the world in 2001. It is located 40 km (25 mi) north of Fort McMurray, Alberta, Canada at the northern end of the Mildred Lake lease owned by Syncrude Canada Ltd.. The dam and the tailings artificial lake within it are constructed and maintained as part of ongoing operations by Syncrude in extracting oil from the Athabasca Oil Sands. Other tailings dams constructed and operated in the same area by Syncrude include the Southwest Sand Storage (SWSS), which is the third largest dam in the world by volume of construction material after the Tarbela Dam. The MLSB, which is the oldest tailings pond in the Athabasca Oil Sands Region (AOSR), was found in a 2018 report published in the Atmospheric Chemistry and Physics journal to be "responsible for the majority of tailings ponds emissions of methane."
  On 31 December 2018, Syncrude was fined $2.75 million after pleading guilty under the federal Migratory Birds Convention Act (MBCA) and Alberta's Environmental Protection and Enhancement Act in relation to the deaths of 31 great blue herons in August 2015 at the MLSB. At the time the MLSB inactive sump "was not covered by Syncrude's waterfowl protection plan to deter birds from landing at tailings areas". Doreen Cole, who has been Managing Director of Syncrude Canada since December 2017, "We immediately took steps to bring all these areas on our Mildred Lake and Aurora sites into our waterfowl protection plan. We're committed to being a responsible operator and this has strengthened our resolve to reduce the impact of our operations on wildlife." On 22 October 2010 Syncrude was found guilty under the provincial and federal Acts and was fined $3-million, which at that time represented the "largest environmental penalty in Alberta history." In 2008, 1,606 ducks died in Syncrude's tailings ponds, which at that time covered an area of 12-square-kilometres, because "cannons, effigies and other deterrents", intended for use to deter migratory birds, had not been deployed. Syncrude's trial lawyer at that time, Robert White, had urged his client to challenge the guilty verdict. But Syncrude spokeswoman said that they would plead guilty and pay the fine as, "At Syncrude, we're eager to move forward. The incident haunted us and we regret that it ever happened."
caption: Syncrude tailings dam
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