Reclamation of oil sands fine tails: Water capping option
- Syncrude Canada Ltd., Edmonton, Alberta (Canada)
- Golder Associates Ltd., Calgary, Alberta (Canada)
Syncrude Canada Ltd., located in northeastern Alberta, produces over 10{sup 7}M{sup 3} per year of a sweet crude oil (SSC) from the extraction and upgrading of bitumen from oil sand. Large volumes (about 0.1--0.2 m{sup 3} per t of ore processed) of mature fine tails (MFT) result from the extraction of oilsands using flotation methods (Clark Hot Water Extraction). MFT is a slowly densifying aqueous suspension of fines (> 35wt%) and unrecovered hydrocarbons (2wt%). The water associated with the fine tails is acutely toxic and cannot be directly released into a receiving environment. Since there is no discharge, the fluid wastes from the extraction process are stored in large settling ponds. At the present rate of growth, about a billion cubic meters of MFT will need to be reclaimed when operations cease. Because of the large volumes, an integrated approach using various reclamation options, including enhanced dewatering, co-disposal with other materials (sand, clays) or incorporation into a lake environment, is being examined. The theological properties of the MFT make the disposal of this material as a fluid in a water capped lake system, a viable alternative. Transfer of the MFT into geotechnically stable containment areas (mined out pits) and the capping of it with a layer of water are being studied as an environmentally acceptable reclamation method. The physical, biological, toxicological and chemical impacts of the MFT on the water capping layer have been followed in lab and field studies. Data have been used to develop and refine a model of how the lake environment will evolve. The development of a stable, productive and self-sustaining lake ecosystem in the water capping layer in contact with MFT appears to be feasible.
- OSTI ID:
- 242332
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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