Addition of Tubifex accelerates dewatering of oil sands tailings

2016 ◽  
Vol 43 (12) ◽  
pp. 1025-1033 ◽  
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Oil Sands ◽  
Land Reclamation ◽  
Test Results ◽  
Anionic Polymer ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Oil Sands Tailings ◽  
Set Up ◽  
Solids Content

Accelerating dewatering of fluid fine tailings (FFT) to facilitate land reclamation is a major challenge to the oil sands industry in Canada. A new method was tested, addition of Tubifex to FFT. Tubifex is an indigenous earthworm in Canada. The survival rate tests showed that Tubifex can survive in oil sands tailings and penetrate to 42 cm depth (maximum depth tested). Columns (5 L of FFT) were set-up with tailings alone, Tubifex treated tailings and polymer-Tubifex treated tailings. Test results showed that (a) the final mud–water interface of tailings alone was 26% higher than that of Tubifex treated tailings; (b) solids content of Tubifex treated tailings was 21% more than that of tailings alone; (c) Tubifex was capable to accelerate the dewatering process of both cationic and anionic polymer treated tailings; (d) anionic polymer was superior in facilitating long-term dewatering and its coupled effects with Tubifex were better than the cationic polymer.

Effect of various treatments on consolidation of oil sands fluid fine tailings

2018 ◽  
Vol 55 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
G. Ward Wilson ◽  
Louis K. Kabwe ◽  
Nicholas A. Beier ◽  
J. Don Scott
Keyword(s):  
Shear Strength ◽  
Oil Sands ◽  
Large Strain ◽  
Regulatory Requirements ◽  
Freeze Thaw ◽  
Treatment Processes ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Solids Content ◽  
And Storage

Regulatory policy and regulations in Alberta require oil sands companies to reduce their production and storage of fluid fine tailings by creating deposits that can be reclaimed in a timely manner. To meet the regulatory requirements, some companies are adding flocculants to the fluid fine tailings and then using thickeners, inline flocculation or centrifuges to increase the solids content. Freeze–thaw and drying processes are then used to further dewater the tailings. The effects of flocculating, thickening, and freeze–thaw treatments were investigated by performing large-strain consolidation and shear strength tests on these treated fluid fine tailings. The consolidation and shear strength results were then compared with those of untreated fluid fine tailings. All of the treatments increased the hydraulic conductivity of the fluid fine tailings to some degree, but had little to no effect on the compressibility and shear strength. The effects of the treatment processes are discussed and evaluated.

Thermal properties of oil sands fluid fine tailings: laboratory and in situ testing methods

2017 ◽  
Vol 54 (3) ◽  
pp. 428-440 ◽  
Author(s):  
Kathryn A. Dompierre ◽  
S. Lee Barbour
Keyword(s):  
Thermal Properties ◽  
Oil Sands ◽  
Elevated Temperatures ◽  
Field Testing ◽  
Extraction Process ◽  
Open Pit ◽  
Fine Tailings ◽  
Oil Sands Mining ◽  
Fluid Fine Tailings

Fluid fine tailings (FFT) are soft tailings produced by the bitumen extraction process associated with open-pit oil sands mining. Oil sands mine operators have proposed the use of end pit lakes (EPLs) to contain soft tailings and Syncrude Canada Ltd. has developed the first EPL in the industry. This EPL, referred to as Base Mine Lake, contains FFT transferred from an above-ground tailings facility in a mined-out pit. The FFT was placed at elevated temperatures relative to natural groundwater temperatures in the region, so the FFT will act as a long-term source of heat. Evaluation of the thermal regime within the EPL requires the characterization of the thermal properties of FFT. Laboratory testing was undertaken to measure the thermal properties (thermal conductivity and volumetric heat capacity) of the FFT over a range of water contents and to evaluate the effect of bitumen content on the thermal properties. Field testing was also undertaken to verify that these properties were similar in the undisturbed FFT, measured at a larger scale.

Capping dewatered oil sands fluid fine tailings with salvaged reclamation soils at varying depths to grow woody plants

2020 ◽  
Vol 100 (4) ◽  
pp. 546-557
Author(s):  
Ryan S. Lalonde ◽  
Bradley D. Pinno ◽  
M. Derek MacKenzie ◽  
Nicholas Utting
Keyword(s):  
Plant Growth ◽  
Populus Tremuloides ◽  
Oil Sands ◽  
Land Reclamation ◽  
Surface Mining ◽  
High Water ◽  
High Water Content ◽  
Trembling Aspen ◽  
Fine Tailings ◽  
Fluid Fine Tailings

Managing fluid fine tailings (FFT) present a major cause of industrial and environmental concerns in oil sands surface mining production. A potential management solution is to dewater and cap the FFT solids for use in land reclamation. A 16 wk greenhouse study was conducted to assess whether FFT centrifuge cake with caps of various reclamation soil mixes (forest floor mineral mix, peat mineral mix, and a mixture of both) and depths (0, 5, 10, and 20 cm) would support growth of trembling aspen (Populus tremuloides — native broadleaf tree) and beaked willow (Salix bebbiana — native broadleaf shrub). Beaked willow had a much greater survival rate (100%) when grown directly in FFT cake compared with trembling aspen (16.7%). Plants grown directly in FFT cake were negatively impacted by high water content, low nitrate supply rates, and high metal concentrations with beaked willow seedlings having 10 times higher foliar concentrations of Al, Cr, and Ti compared with any other treatments. Adding soil caps substantially increased aboveground biomass for both species, but differences among soil cap types and depths did not have as significant of an effect on plant growth. Results from this study show that capping FFT substantially improves woody plant growth, and S. bebbiana and P. tremuloides are potentially suitable species for tailings reclamation.

10 m standpipe tests on oil sands tailings: long-term experimental results and prediction

2009 ◽  
Vol 46 (8) ◽  
pp. 875-888 ◽  
Author(s):  
S. Jeeravipoolvarn ◽  
J. D. Scott ◽  
R. J. Chalaturnyk
Keyword(s):  
Effective Stress ◽  
Oil Sands ◽  
Large Scale ◽  
Material Behavior ◽  
Compression Behavior ◽  
University Of Alberta ◽  
Fine Tailings ◽  
Oil Sands Tailings ◽  
Set Up ◽  
Conventional Behavior

Three large 10 m high standpipe tests were set up at the University of Alberta in 1982 to simulate large-scale compression behavior of oil sands tailings in a controlled environment. The objectives of the tests were to study material behavior and to provide consolidation performance for theoretical verification. Three tailings materials (fine tailings and two mixes of fine tailings and sand) were used. Test results showed that the fine tailings, standpipe 1, strained more than 30% over a 25 year monitoring period by self-weight with very little to no effective stress developing, while the mix of fine tailings and sand, standpipe 3, compressed with a significant effective stress development. The tailings in standpipe 1 can be regarded as a class of material where a reduction in volume is not governed by a unique relationship between effective stress and void ratio, whereas the tailings in standpipe 3 can be categorized as slurry with conventional behavior. To investigate the capability of the finite strain consolidation theory on these tailings, a numerical model with appropriate material constitutive relationships was developed and used to make predictions. Numerical results, compared with the performance of the standpipe tests, indicated that the theory overestimated the compression behavior of the standpipe 1 material, but it could predict the standpipe 3 consolidation behavior.

Laboratory device to characterize electrokinetic geocomposites for fluid fine tailings dewatering

2015 ◽  
Vol 52 (4) ◽  
pp. 505-514 ◽  
Author(s):  
Sébastien Bourgès-Gastaud ◽  
Guillaume Stoltz ◽  
Patricia Dolez ◽  
Éric Blond ◽  
Nathalie Touze-Foltz
Keyword(s):  
Oil Sands ◽  
Mean Value ◽  
Drain Water ◽  
Sludge Dewatering ◽  
Fine Tailings ◽  
Electro Osmosis ◽  
Laboratory Device ◽  
Fluid Fine Tailings ◽  
Solids Content

The oil sands industry usually leads to the production of large quantities of mineral waste, such as fluid fine tailings (FFT), whose disposal is often challenging. Electrokinetic geocomposites (eGCPs) installed into the FFT disposal area may improve in situ dewatering, as eGCPs can drain water expulsed during FFT consolidation as well as impose a voltage across FFT to displace water by electro-osmosis. This paper presents a laboratory device specifically developed to evaluate eGCP performance for sludge dewatering. Based on the oedometer principle, the device aims at studying sludge consolidation as a function of boundary conditions (mechanical stress and (or) voltage), with drainage and electrical conduction ensured by two eGCPs positioned on both sides of the sludge layer. Preliminary results obtained with one particular eGCP are presented: the solids content was increased from 42% to 66%, which led to a significant improvement of the shear strength from nearly 0 kPa to a mean value of 40 kPa. The energy required for this experiment was 71 W·h (3.5 kW·h/(m3 of sludge)). The filtration performance remained satisfactory; the sludge particles were retained upstream of the filter, with clean water flowing through.

scholarly journals Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1582
Author(s):  
Yeling Zhu ◽  
Yuki Gong ◽  
Heather Kaminsky ◽  
Michael Chae ◽  
Paolo Mussone ◽  
...  
Keyword(s):  
Oil Sands ◽  
Colloidal Stability ◽  
Free Water ◽  
Value Added ◽  
Settling Rate ◽  
Test Range ◽  
Tailings Management ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Hydrolyzed Polyacrylamide

Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.

Impact of flocculation-based dewatering on the shear strength of oil sands fine tailings

2013 ◽  
Vol 50 (9) ◽  
pp. 1001-1007 ◽  
Author(s):  
Nicholas Beier ◽  
Ward Wilson ◽  
Adedeji Dunmola ◽  
David Sego
Keyword(s):  
Oil Sands ◽  
Material Handling ◽  
Performance Criteria ◽  
Regulatory Requirements ◽  
Strength Performance ◽  
Tailings Management ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Management Techniques ◽  
Reported Data

The oil sands in northern Alberta have been mined to produce bitumen over the past five decades. Since the 1980s, technical advances have been made in mining, material handling, and bitumen extraction. However, acquiring practical methods to control and reduce the fluid fine tailings build-up has been an ongoing challenge. Recent regulatory changes have driven the industry to review current tailings-management techniques and investigate numerous alternative technologies and processes to manage and reclaim fine tailings. Many of these fine tailings–management techniques involve some form of polymer or chemical addition to promote dewatering and strength gain to meet the regulatory requirements. Based on the reported data, the chemically amended fine tailings deposits have the characteristics of sensitive, metastable deposits, necessitating additional mitigative measures by oil sands operators beyond the regulatory requirements. This paper explores the geotechnical aspects of meeting regulatory strength performance criteria by employing flocculation-based dewatering of fluid fine tailings.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

Investigating the Microbial Degradation Potential in Oil Sands Fluid Fine Tailings Using Gamma Irradiation: A Metagenomic Perspective

2017 ◽  
Vol 74 (2) ◽  
pp. 362-372 ◽  
Author(s):  
Danielle VanMensel ◽  
Subba Rao Chaganti ◽  
Ryan Boudens ◽  
Thomas Reid ◽  
Jan Ciborowski ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Microbial Degradation ◽  
Oil Sands ◽  
Fine Tailings ◽  
Fluid Fine Tailings
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