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

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.

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

Canadian Geotechnical Journal ◽

10.1139/cgj-2012-0262 ◽

2013 ◽

Vol 50 (9) ◽

pp. 1001-1007 ◽

Cited By ~ 42

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.

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Addition of Tubifex accelerates dewatering of oil sands tailings

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2016-0308 ◽

2016 ◽

Vol 43 (12) ◽

pp. 1025-1033 ◽

Cited By ~ 1

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.

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Laboratory device to characterize electrokinetic geocomposites for fluid fine tailings dewatering

Canadian Geotechnical Journal ◽

10.1139/cgj-2014-0031 ◽

2015 ◽

Vol 52 (4) ◽

pp. 505-514 ◽

Cited By ~ 12

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.

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

Materials ◽

10.3390/ma14071582 ◽

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.

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Impact of chemical and physical treatments on freeze-thaw dewatering of fluid fine tailings

Cold Regions Science and Technology ◽

10.1016/j.coldregions.2021.103385 ◽

2022 ◽

Vol 193 ◽

pp. 103385

Author(s):

Yunhui Li ◽

Heather Kaminsky ◽

Ardalan Sadighian ◽

Yijia Simon Sun ◽

Fergus Murphy ◽

...

Keyword(s):

Freeze Thaw ◽

Fine Tailings ◽

Fluid Fine Tailings ◽

Physical Treatments

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

Microbial Ecology ◽

10.1007/s00248-017-0953-7 ◽

2017 ◽

Vol 74 (2) ◽

pp. 362-372 ◽

Cited By ~ 7

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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Characterization of physical mass transport through oil sands fluid fine tailings in an end pit lake: a multi-tracer study

Journal of Contaminant Hydrology ◽

10.1016/j.jconhyd.2016.03.006 ◽

2016 ◽

Vol 189 ◽

pp. 12-26 ◽

Cited By ~ 14

Author(s):

Kathryn A. Dompierre ◽

S. Lee Barbour

Keyword(s):

Mass Transport ◽

Oil Sands ◽

Tracer Study ◽

Pit Lake ◽

Physical Mass ◽

Fine Tailings ◽

Fluid Fine Tailings

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Suspended solids in an end pit lake: potential mixing mechanisms

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2015-0381 ◽

2016 ◽

Vol 43 (3) ◽

pp. 211-217 ◽

Cited By ~ 11

Author(s):

Gregory A. Lawrence ◽

Edmund W. Tedford ◽

Roger Pieters

Keyword(s):

Oil Sands ◽

Suspended Solids ◽

Salt Water ◽

Wind Waves ◽

Vertical Mixing ◽

Pit Lake ◽

Surface Cooling ◽

Activity Data ◽

Fine Tailings ◽

Fluid Fine Tailings

The production of crude oil from the Canadian oil sands has generated tailings ponds that contain oil sands process-affected water and oil sands fluid fine tailings (FFT). One remediation strategy is to backfill a mined out pit with FFT and cap this with a mix of oil sands process-affected water and fresh water to form a lake, called an end pit lake. Here we discuss various mechanisms governing the vertical mixing of suspended solids in an end pit lake. Depending on the depth of the water cap, wind waves can cause mixing between the water cap and the FFT. Other potential mixing mechanisms include: convection due to salt-water exclusion during ice formation, penetrative convection due to surface cooling, gas emission from the FFT, and internal wave activity. Data collected at Syncrude Canada Limited’s Base Mine Lake in 2013 and 2014 are used to demonstrate the effects of some of these processes.

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Effects of Calcium and Aluminum on Particle Settling in an Oil Sands End Pit Lake

Mine Water and the Environment ◽

10.1007/s10230-021-00808-9 ◽

2021 ◽

Author(s):

Kai Wei ◽

Heidi L. Cossey ◽

Ania C. Ulrich

Keyword(s):

Surface Water ◽

Oil Sands ◽

Surface Mining ◽

Pit Lake ◽

Particle Settling ◽

Pit Lakes ◽

Fine Tailings ◽

High Turbidity ◽

Fluid Fine Tailings ◽

Al Treatment

AbstractSurface mining of oil sands ore in Alberta, Canada has generated fluid fine tailings (FFT) that must be reclaimed. End pit lakes (EPLs), which consist of thick deposits of FFT capped with water, have been proposed for FFT reclamation, and Base Mine Lake (BML) is the first full-scale demonstration EPL. However, FFT particle settling and resuspension contributes to high turbidity in the BML water cap, which may be detrimental to the development of an aquatic ecosystem. This study investigated the effect of Ca and Al treatments on turbidity mitigation. The initial turbidity was reduced from 20 NTU to less than 2 NTU in BML surface water treated with 54 mg/L of Ca or 1.1 mg/L of Al. At a concentration of 1.1 mg/L, Al reduced the initial turbidity to a greater extent, and in a shorter time, than 54 mg/L of Ca. Further, resuspended Al-treated FFT particles were 100–700 nm larger in diameter, and thus resettled faster than the resuspended untreated or Ca-treated FFT particles. The final turbidity values 21 days after resuspension of untreated and 1.7 mg/L Al-treated FFT particles in fresh BML surface water were 20.5 NTU and 2.5 NTU, respectively. Thus, Al treatment may be effective in mitigating turbidity in BML through both Al-induced coagulation and self-weight settling of the resuspended Al-treated FFT particles.

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