METHANE EBULLITION CAN INFLUENCE INTERNAL MASS LOADING IN OIL SANDS END PIT LAKES

2019 ◽  
Author(s):  
Daniel Francis ◽  
◽  
Matthew B.J. Lindsay ◽  
Lee Barbour
Keyword(s):  
Oil Sands ◽  
Internal Mass ◽  
Mass Loading ◽  
Pit Lakes ◽  
Methane Ebullition

scholarly journals Geochemical Stability of Oil Sands Tailings in Mine Closure Landforms

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 830
Author(s):  
Heidi L. Cossey ◽  
Anya E. Batycky ◽  
Heather Kaminsky ◽  
Ania C. Ulrich
Keyword(s):  
Oil Sands ◽  
Chemical Constituents ◽  
Surface Mining ◽  
Past Research ◽  
Mass Loading ◽  
Water Fluxes ◽  
Mine Closure ◽  
Pit Lakes ◽  
Tailings Ponds

Oil sands surface mining in Alberta has generated over a billion cubic metres of waste, known as tailings, consisting of sands, silts, clays, and process-affected water that contains toxic organic compounds and chemical constituents. All of these tailings will eventually be reclaimed and integrated into one of two types of mine closure landforms: end pit lakes (EPLs) or terrestrial landforms with a wetland feature. In EPLs, tailings deposits are capped with several metres of water while in terrestrial landforms, tailings are capped with solid materials, such as sand or overburden. Because tailings landforms are relatively new, past research has heavily focused on the geotechnical and biogeochemical characteristics of tailings in temporary storage ponds, referred to as tailings ponds. As such, the geochemical stability of tailings landforms remains largely unknown. This review discusses five mechanisms of geochemical change expected in tailings landforms: consolidation, chemical mass loading via pore water fluxes, biogeochemical cycling, polymer degradation, and surface water and groundwater interactions. Key considerations and knowledge gaps with regard to the long-term geochemical stability of tailings landforms are identified, including salt fluxes and subsequent water quality, bioremediation and biogenic greenhouse gas emissions, and the biogeochemical implications of various tailings treatment methods meant to improve geotechnical properties of tailings, such as flocculant (polyacrylamide) and coagulant (gypsum) addition.

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

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.

scholarly journals Isotopic and Chemical Assessment of the Dynamics of Methane Sources and Microbial Cycling during Early Development of an Oil Sands Pit Lake

2021 ◽  
Vol 9 (12) ◽  
pp. 2509
Author(s):  
Greg F. Slater ◽  
Corey A. Goad ◽  
Matthew B. J. Lindsay ◽  
Kevin G. Mumford ◽  
Tara E. Colenbrander Nelson ◽  
...  
Keyword(s):  
Microbial Community ◽  
Water Column ◽  
Oil Sands ◽  
Phospholipid Fatty Acid ◽  
Pit Lake ◽  
Microbial Oxidation ◽  
Dissolved Methane ◽  
Oxidation Rates ◽  
Pit Lakes ◽  
The Impact

Water-capped tailings technology (WCTT) is a key component of the reclamation strategies in the Athabasca oil sands region (AOSR) of northeastern Alberta, Canada. The release of microbial methane from tailings emplaced within oil sands pit lakes, and its subsequent microbial oxidation, could inhibit the development of persistent oxygen concentrations within the water column, which are critical to the success of this reclamation approach. Here, we describe the results of a four-year (2015–2018) chemical and isotopic (δ13C) investigation into the dynamics of microbial methane cycling within Base Mine Lake (BML), the first full-scale pit lake commissioned in the AOSR. Overall, the water-column methane concentrations decreased over the course of the study, though this was dynamic both seasonally and annually. Phospholipid fatty acid (PLFA) distributions and δ13C demonstrated that dissolved methane, primarily input via fluid fine tailings (FFT) porewater advection, was oxidized by the water column microbial community at all sampling times. Modeling and under-ice observations indicated that the dissolution of methane from bubbles during ebullition, or when trapped beneath ice, was also an important source of dissolved methane. The addition of alum to BML in the fall of 2016 impacted the microbial cycling in BML, leading to decreased methane oxidation rates, the short-term dominance of a phototrophic community, and longer-term shifts in the microbial community metabolism. Overall, our results highlight a need to understand the dynamic nature of these microbial communities and the impact of perturbations on the associated biogeochemical cycling within oil sands pit lakes.

scholarly journals Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes

2021 ◽  
Vol 9 (7) ◽  
pp. 1443
Author(s):  
Heidi L. Cossey ◽  
Mian Nabeel Anwar ◽  
Petr V. Kuznetsov ◽  
Ania C. Ulrich
Keyword(s):  
Microbial Communities ◽  
Oil Sands ◽  
Threshold Velocity ◽  
Water Turbidity ◽  
Mixing Speed ◽  
Fine Grained ◽  
Pit Lakes ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
The Impact

End pit lakes (EPLs) have been proposed as a method of reclaiming oil sands fluid fine tailings (FFT), which consist primarily of process-affected water and clay- and silt-sized particles. Base Mine Lake (BML) is the first full-scale demonstration EPL and contains thick deposits of FFT capped with water. Because of the fine-grained nature of FFT, turbidity generation and mitigation in BML are issues that may be detrimental to the development of an aquatic ecosystem in the water cap. Laboratory mixing experiments were conducted to investigate the effect of mudline biofilms made up of microbial communities indigenous to FFT on mitigating turbidity in EPLs. Four mixing speeds were tested (80, 120, 160, and 200 rpm), all of which are above the threshold velocity required to initiate erosion of FFT in BML. These mixing speeds were selected to evaluate (i) the effectiveness of biofilms in mitigating turbidity and (ii) the mixing speed required to ‘break’ the biofilms. The impact of biofilm age (10 weeks versus 20 weeks old) on turbidity mitigation was also evaluated. Diverse microbial communities in the biofilms included photoautotrophs, namely cyanobacteria and Chlorophyta (green algae), as well as a number of heterotrophs such as Gammaproteobacteria, Desulfobulbia, and Anaerolineae. Biofilms reduced surface water turbidity by up to 99%, depending on the biofilm age and mixing speed. Lifting and layering in the older biofilms resulted in weaker attachment to the FFT; as such, younger biofilms performed better than older biofilms. However, older biofilms still reduced turbidity by 69% to 95%, depending on the mixing speed. These results indicate that biostabilization is a promising mechanism for turbidity mitigation in EPLs.

Megaloads and Mobilization

2017 ◽  
Vol 1 (1) ◽  
pp. 1-7
Author(s):  
Corrie Grosse
Keyword(s):  
Oil Sands ◽  
Fossil Fuel ◽  
Cost Effective ◽  
Nez Perce ◽  
Grassroots Organizations ◽  
Canadian Province ◽  
Creation Story ◽  
Oil Companies ◽  
Heavy Crude ◽  
Ways Of Life

From 2011 to 2014 fossil fuel corporations trucked tar sands processing machinery along rural Idaho highways. The machinery was bound for the world's largest deposits of tar or oil sands, a heavy crude oil substance called bitumen, located in the western Canadian province of Alberta. These loads of machinery, what became known as megaloads, encountered much resistance. Throughout Idaho and the surrounding region, a network organized opposition. Neighbors, grassroots organizations, nonprofits, and the Nez Perce and other tribes all collaborated. They held information sessions, protested, waged legal battles, monitored the loads, and blockaded highways. What oil companies hoped would be a cost-effective solution for transporting their megaloads became a David versus Goliath, Coyote versus the Monster—to reference the Nez Perce creation story—struggle to protect rural and indigenous ways of life and sovereignty, and the planet.

Improvements to production planning in oil sands mining through analysis and simulation of truck cycle times

CIM Journal ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
E. Goris Cervantes ◽  
S. P. Upadhyay ◽  
H. Askari-Nasab
Keyword(s):  
Production Planning ◽  
Oil Sands ◽  
Cycle Times ◽  
Oil Sands Mining
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