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Stacked Deposits of Thickened and Filtered Fluid Fine Tailings Using Geotextile Tubes to Enhance Physical Stability of Reclaimed Landforms
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- Author / Creator
- Da Silva, Fernando A.N.
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Thickening tailings by adding synthetic polymer is a common practice in the mining industry. Flocculant alone in the flocculation of the oil sands' fluid fine tailings (FFT) has been used with the expectation that it would be beneficial to fine tailings particle agglomeration and dewatering. Unfortunately, significant amounts of trapped water remain in the flocculated tailings, affecting consolidation timeframes and shear strength gain, and postponing mine closure and reclamation. This research investigates a tailings management technology approach using a geotextile tube that combines filtration, dewatering, densification, and enhancing the geotechnical stability of the FFT, while effectively recycling the process water. To assure that the return water is suitable for reuse in the mine plant processes and that FFT can be dewatered and densified faster, a physicochemical treatment recipe using coagulation and flocculation was designed to assist solids/water separation and ensure fines agglomeration during pipeline transport prior to discharge into the geotextile tubes. As part of this research, a parametric analysis of the FFT dispersion and flocculation behaviors was performed to determine the causes and mechanisms that explain why significant amounts of trapped water remain when FFT is thickened with flocculation only. The parametric analysis was developed based on the fundamentals of soil behavior, supported by facts observed in the laboratory. The parametric analysis findings and recommendations are also included. The Global Industry Standard on Tailings Management (GISTM) aspires toward “zero harm to people and the environment” from tailings facilities. Aligned with the GISTM, this research describes the recipe with geotextile tubes as a feasible solution for safe management of tailings as well as enhanced physical stability of the treated FFT deposits. FFT treated with the defined recipe dewater in the geotextile tubes; the rate of dewatering is a function of the recipe, the inline mixing process, short drainage path provided by geotextile tubes containment, internal pressure and gravity head during filling, hydraulic parameters of the geofabric material, evaporation, freeze-thaw, and the self-weight consolidation, and increased total stress by stacking the geotextile tubes to form stable deposits of thickened and filtered FFT. This research therefore has the potential to change the way mine tailings are managed by greatly reducing geotechnical risk and the complexity of closure, compared with traditional methods.
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- Subjects / Keywords
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- Graduation date
- Fall 2023
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.