Syncrude Canada Ltd. has let two contracts to KBR for module fabrication and field construction of a full-scale plant for processing tailings from its oil sands mines northeast of Fort McMurray, Alta.
The plant will dewater fine tailings with centrifuges in a process that Syncrude says reduces overall volume by 50% or more. The process yields a soft, clay-rich material that can be used in land reclamation. Water is recycled for plant operations.
The new facility will represent the first phase of a commercial plant due in operation by 2015.
Centrifuging technology is one of Syncrude’s responses to a 2009 directive on tailings management by the Energy Resources Conservation Board of Alberta (OGJ Online, Dec. 2, 2009).
Other tailings-management methods Syncrude is developing include water-capping, in which fresh water is deposited over tailings in a settling pond to form a lake, and composite tails, in which the addition of gympsum and sand accelerates the settling of fine tails.
Tailing ponds hold the mixture of water, solids, and other fluids left over from the initial processing of mined oil sands. Because fine tailings settle out slowly, cycling of tailing ponds can require decades. In the meantime, more tailing ponds must be built, requiring more surface disturbance.
The ERCB’s tailings-management directive addressed that problem. Earlier this year a study conducted for Alberta Innovates—Energy and Environment Solutions, a government agency, by an industry consortium outlined nine “roadmaps” for tailings management (OGJ Online, Aug. 31, 2012).
