| Title | Long-term column leaching study of centrifuged oil sands fine tailings |
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| Author | Utting, N |
| Source | Environmental Earth Sciences vol. 80, 462, 2021 p. 1-21, https://doi.org/10.1007/s12665-021-09707-2 |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210290 |
| Publisher | Springer |
| Document | serial |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Alberta |
| NTS | 82; 83; 84; 72E; 72L; 72M; 73D; 73E; 73L; 73M; 74D; 74E; 74L; 74M |
| Lat/Long WENS | -120.0000 -110.0000 60.0000 49.0000 |
| Subjects | fossil fuels; Science and Technology; oil sands; reclamation; tailings; tailings analyses; water quality; leaching |
| Illustrations | photographs; tables; photomicrographs; histograms; plots |
| Program | CanmetENERGY - Devon Director, Upstream and Environmental Impacts - Upstream and Environmental Impacts Operations |
| Released | 2021 07 04 |
| Abstract | In northeastern Alberta, oil sands deposits are mined and processed to extract bitumen, which is then converted to synthetic crude oil, a waste stream of this extraction process is fluid fine tailings.
Seepage and leaching from these tailings have the potential to negatively impact surface and groundwater quality. This research focuses on improving and understanding dissolved ions that may seep from treated oil sands fine tailings using long-term
column leaching experiments. Concentrations of dissolved ions in water leaching from the columns were measured over nineteen months. For most ions, changes in concentration were as expected, generally decreasing once a peak concentration was reached
soon after the start of the experiment. However, some ion concentrations, particularly those of magnesium and strontium, increased late in the experiment. When at maximum concentration, for two to three pore volumes, the leachate (or eluant) from the
columns exceeded Alberta Tier 1 guidelines (groundwater remediation guidelines for sodium, arsenic and zinc). The Tier 1 guideline for sodium is 200 mg/L and was exceeded during discharge from all four columns for at least some part of the
experiment. Leachate also exceeded Canadian Council of Ministers of the Environment water quality guidelines for protection of aquatic life for manganese and occasionally for cadmium, copper, lead and nickel. |
| Summary | (Plain Language Summary, not published)
In northeastern Alberta, oil sand deposits are mined and processed to extract bitumen. The extraction leaves large areas of land that will need to be
reclaimed following mining. Waste produced by the oil extraction process include fluid tailings, which, even with treatment, can take many years to settle to be strong enough to support vegetation. Without treatment, the solids do not settle beyond a
still-fluid state. Additionally, the tailings contain contains trace metal contaminants, elevated total dissolved solids (TDS) and dissolved organic such as naphthenic acids. This research focuses on improving our understanding of what elements will
leach from oil sands tailings over time. The study presented in this paper presents a long terms column leaching test of dewatered fine oil sands tailings. For most elements measured the concentration leaching decreases over time, however the
concentration of some elements increase late in the experiment. This may be related to degradation of polymer used to treat tailings. |
| GEOSCAN ID | 328945 |
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