Measurement of hydraulic conductivity in oil sand tailings slurries

1996 ◽  
Vol 33 (4) ◽  
pp. 642-653 ◽  
Author(s):  
Nagula N Suthaker ◽  
J Don Scott
Keyword(s):  
Hydraulic Conductivity ◽  
Oil Sands ◽  
Void Ratio ◽  
Large Strain ◽  
Measurement Techniques ◽  
Hydraulic Gradient ◽  
Oil Sand ◽  
Fines Content ◽  
Acid Lime ◽  
Clamping Device

Fine tails, the resulting fine waste from oil sand processing, undergoes large-strain consolidation in tailings ponds. Its consolidation behaviour must be analyzed using a large-strain consolidation theory, which requires the determination of the relationship between the void ratio and hydraulic conductivity. Conventional measurement techniques are not suitable for fine tails, and a special slurry consolidometer, with a clamping device to prevent seepage-induced consolidation, was designed to determine the hydraulic conductivity of the fine tails and nonsegregating fine tails – sand slurries. The hydraulic conductivity of slurries is not constant but decreases with time to a steady-state value. Hydraulic conductivity is also influenced by the hydraulic gradient and bitumen content. It is shown that a low hydraulic gradient, less than 0.2, is necessary to counteract the effect of the bitumen and to represent tailings pond conditions. The hydraulic conductivity of fine tails – sand mixes is controlled by the fines void ratio, hence, fines content. The hydraulic conductivity of chemically amended nonsegregating tailings can be lower than that of fine tails. However, acid–lime or acid – fly ash amended nonsegregating tailings have similar hydraulic conductivity values in terms of fines void ratio. The hydraulic conductivity of nonsegregating tailings appears to be governed by fines content and by the nature of the fines aggregation caused by the chemical additive. Key words: tailings, slurries, hydraulic conductivity, slurry consolidometer, nonsegregating tailings, oil sands.

scholarly journals One-dimensional large-strain thaw consolidation using nonlinear effective stress – void ratio – hydraulic conductivity relationships

2018 ◽  
Vol 55 (3) ◽  
pp. 414-426 ◽  
Author(s):  
Simon Dumais ◽  
Jean-Marie Konrad
Keyword(s):  
Heat Transfer ◽  
Hydraulic Conductivity ◽  
Effective Stress ◽  
Void Ratio ◽  
Moving Boundary ◽  
Initial Conditions ◽  
Large Strain ◽  
One Dimensional ◽  
Consolidation Theory ◽  
Thaw Consolidation

A one-dimensional model for the consolidation of thawing soils is formulated in terms of large-strain consolidation and heat-transfer equations. The model integrates heat transfer due to conduction, phase change, and advection. The hydromechanical behaviour is modelled by large-strain consolidation theory. The equations are coupled in a moving boundary scheme developed in Lagrangian coordinates. Finite strains are allowed and nonlinear effective stress – void ratio – hydraulic conductivity relationships are proposed to characterize the thawing soil properties. Initial conditions and boundary conditions are presented with special consideration for the moving boundary condition at the thaw front developed in terms of large-strain consolidation. The proposed model is applied and compared with small-strain thaw consolidation theory in a theoretical working example of a thawing fine-grained soil sample. The modelling results are presented in terms of temperature, thaw penetration, settlements, void ratio, and excess pore-water pressures.

Compressibility and Permeability of Sand-Silt Tailings Mixtures

2022 ◽  
Author(s):  
Jiying Fan ◽  
R. Kerry Rowe ◽  
Richard W.I. Brachman
Keyword(s):  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Published Data ◽  
Internal Stability ◽  
Fines Content ◽  
Coarse Grains ◽  
Soil Skeleton ◽  
Loading Tests ◽  
Stress Dependent ◽  
Incremental Loading

Microstructure showing the involvement of the fine and coarse grains in the soil skeleton is evaluated. Incremental loading tests using a stress-dependent permeameter are conducted on the mixtures of poorly graded sand and nonplastic fines originating from tailings. The results are compared with the published data of various tailings. It is shown that increasing the fines content from 0 to 100%, the involvement of the fine and coarse components of soil skeleton can be classified into four categories: no fines involvement (<10% fines), fines partially involved (10% —35% fines), increasing cushioning effect surrounding the coarse (35% — 40% fines), and constant cushioning effect (> 40% fines). At the same consolidation stress, the void ratio, e, rapidly decreases for fines less than 30%, then almost remains constant between 30% and 50% fines, and gradually increases for fines exceeding 50%. The hydraulic conductivity, k, decreases more than 20-fold as the fines content increases from 12% to 50%, then remains constant. k is proportional to [e3/(1+e)]A and inversely proportional to S2, where A is a factor describing the effect of particle angularity and S is the specific surface. Finally, the influence of fines content on the seepage-induced internal stability is discussed.

Estimation of the fines content of Athabasca oil sands using instrumental neutron activation analysis

1996 ◽  
Vol 74 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Kingsley K. Donkor ◽  
Byron Kratochvil ◽  
M. John M. Duke
Keyword(s):  
Neutron Activation Analysis ◽  
Instrumental Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Oil Sands ◽  
Oil Sand ◽  
Fines Content ◽  
Bulk Oil ◽  
Mineral Fraction ◽  
Instrumental Neutron Activation

Knowledge of the "fines" or clay-rich mineral fraction is necessary for the efficient extraction of bitumen from bulk oil sands, and has environmental implications in tailings disposal. Current methods for estimating the fines in oil sand are laborious and of questionable accuracy. We propose here their estimation directly in bulk oil sand by instrumental neutron activation analysis (INAA) of the trace and major elements determinable. Correlations between fines content and individual elements fall in the range of 0.80 to 0.81 for dysprosium, samarium, and europium, and 0.75 to 0.77 for sodium, potassium, aluminum, and titanium. These results follow the expected geochemical relationships between major and trace elements and the mineral fraction of the oil sands. Principal component analysis (PCA) using a combination of elements gave correlations with fines content no better than those obtained from individual elements. However, the PCA approach can be considered more robust. Advantages of INAA over conventional methods to estimate the fines content of unprocessed oil sand include minimal sample preparation (including elimination of the use of organic solvents), rapid turnaround time, and the potential for automation. Key words: instrumental neutron activation analysis, oil sand, elemental correlations, fines.

Stress–strain response of Cold Lake oil sands

1993 ◽  
Vol 30 (2) ◽  
pp. 220-235 ◽  
Author(s):  
R. C. K. Wong ◽  
W. E. Barr ◽  
P. R. Kry
Keyword(s):  
Pore Pressure ◽  
Critical State ◽  
Oil Sands ◽  
Void Ratio ◽  
Stress Path ◽  
Strain Response ◽  
Oil Sand ◽  
Stress Strain ◽  
Sample Disturbance ◽  
Cold Lake

The stress–strain response of Cold Lake oil sands at confining stresses and temperatures up to 18 MPa and 200 °C, respectively, was studied in a triaxial apparatus using 89-mm full diameter cores. Tests that have been performed include conventional triaxial tests such as hydrostatic compression, initial Young's modulus determination, and cyclic drained and undrained compression. Tests involving pore-pressure increase and decrease under constant total stresses were also performed to simulate the stress path encountered in the field during the cyclic steam stimulation process. Treating oil sand as a particulate medium, possible modes of granular interaction were explored for all tests along different stress paths. Four modes of granular interaction were identified: (i) contact elastic deformation, (ii) rolling, (iii) shear dilation, and (iv) crushing. These modes provide a useful framework for explaining the behaviour arising from the effects of variation in void ratio owing to sample disturbance, stress level, stress path, induced anisotropy, and temperature. Other behaviour relating to critical state, localized shear deformation, and load–unload–reload are also examined. Key words : oil sand, stress, strain, void ratio, pore pressure, temperature, mode of granular interaction, critical state.

Predicting the saturated hydraulic conductivity of sand and gravel using effective diameter and void ratio

2004 ◽  
Vol 41 (5) ◽  
pp. 787-795 ◽  
Author(s):  
Robert P Chapuis
Keyword(s):  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Saturated Hydraulic Conductivity ◽  
Effective Diameter ◽  
Predictive Capacity ◽  
K Value ◽  
Maximum Value ◽  
New Equation ◽  
Silty Soils ◽  
Sand And Gravel

This paper assesses methods to predict the saturated hydraulic conductivity, k, of clean sand and gravel. Currently, in engineering, the most widely used predictive methods are those of Hazen and the Naval Facilities Engineering Command (NAVFAC). This paper shows how the Hazen equation, which is valid only for loose packing when the porosity, n, is close to its maximum value, can be extended to any value of n the soil can take when its maximum value of n is known. The resulting extended Hazen equation is compared with the single equation that summarizes the NAVFAC chart. The predictive capacity of the two equations is assessed using published laboratory data for homogenized sand and gravel specimens, with an effective diameter d10 between 0.13 and 1.98 mm and a void ratio e between 0.4 and 1.5. A new equation is proposed, based on a best fit equation in a graph of the logarithm of measured k versus the logarithm of d102e3/(1 + e). The distribution curves of the differences “log(measured k) – log(predicted k)” have mean values of –0.07, –0.21, and 0.00 for the extended Hazen, NAVFAC, and new equations, respectively, with standard deviations of 0.23, 0.36, and 0.10, respectively. Using the values of d10 and e, the new equation predicts a k value usually between 0.5 and 2.0 times the measured k value for the considered data. It is shown that the predictive capacity of this new equation may be extended to natural nonplastic silty soils, but not to crushed soils or plastic silty soils. The paper discusses several factors affecting the inaccuracy of predictions and laboratory test results.Key words: permeability, sand, prediction, porosity, gradation curve.

Experimental Study on the Piping Erosion Mechanism of Gap-Graded Soils Under a Supercritical Hydraulic Gradient

2021 ◽  
Author(s):  
Liang Chen ◽  
Yu Wan ◽  
Jian-Jian He ◽  
Chun-Mu Luo ◽  
Shu-fa Yan ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Unsteady Flow ◽  
Relative Density ◽  
Flow Velocity ◽  
Steady Flow ◽  
Fine Particle ◽  
Failure Process ◽  
Hydraulic Gradient ◽  
Particle Content ◽  
Piping Erosion

Abstract Seepage-induced piping erosion is observed in many geotechnical structures. This paper studies the piping mechanism of gap-graded soils during the whole piping erosion failure process under a supercritical hydraulic gradient. We define the supercritical ratio Ri and study the change in the parameters such as the flow velocity, hydraulic conductivity, and fine particle loss with Ri. Under steady flow, a formula for determining the flow velocity state of the sample with Ri according to the fine particle content and relative density of the sample was proposed; during the piping failure process, the influence of Rimax on the rate at which the flow velocity and hydraulic conductivity of the sample increase as Ri decreases was greater than that of the initial relative density and the initial fine particle content of the sample. Under unsteady flow, a larger initial relative density corresponds to a smaller amplitude of increase in the average value of the peak flow velocity with increasing Ri. Compared with the test under steady flow, the flow velocity under unsteady flow would experience abrupt changes. The relative position of the trend line L of the flow velocity varying with Ri under unsteady flow and the fixed peak water head height point A under steady flow were related to the relative density of the sample.

scholarly journals Effects of Hydraulic Gradient and Clay Type on Permeability of Clay Mineral Materials

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1064
Author(s):  
Masanori Kohno
Keyword(s):  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Clay Mineral ◽  
Specific Surface Area ◽  
Hydraulic Gradient ◽  
Consistency Index ◽  
Hydrogen Energy ◽  
The Difference ◽  
Mineral Type

Considering the relevance of clay mineral-bearing geomaterials in landslide/mass movement hazard assessment, various engineering projects for resource development, and stability evaluation of underground space utilization, it is important to understand the permeability of these clay mineral-based geomaterials. However, only a few quantitative data have been reported to date regarding the effects of the clay mineral type and hydraulic gradient on the permeability of clay mineral materials. This study was conducted to investigate the permeability of clay mineral materials based on the clay mineral type, under different hydraulic gradient conditions, through a constant-pressure permeability test. Comparative tests have revealed that the difference in the types of clay mineral influences the swelling pressure and hydraulic conductivity. In addition, it has been found that the difference in water pressure (hydraulic gradient) affects the hydraulic conductivity of clay mineral materials. The hydraulic conductivity has been found to be closely associated with the specific surface area of the clay mineral material. Furthermore, the hydraulic conductivity value measured is almost consistent with the value calculated theoretically using the Kozeny–Carman equation. Moreover, the hydraulic conductivity is also found to be closely associated with the hydrogen energy, calculated from the consistency index of clay. This result suggests that the hydraulic conductivity of clay mineral materials can be estimated based on the specific surface area and void ratio, or consistency index of clay.

Status of the Development and Application of Oil Sand

2012 ◽  
Vol 562-564 ◽  
pp. 367-370
Author(s):  
Jia He Chen
Keyword(s):  
Oil Sands ◽  
Former Soviet Union ◽  
Global Economy ◽  
Raw Materials ◽  
Rapid Development ◽  
The United States ◽  
Oil Sand ◽  
Unconventional Oil ◽  
Oil Resources ◽  
Conventional Oil

Oil and natural gas are important energy and chemical raw materials, its resources are gradually reduced. With the rapid development of the global economy, the conventional oil resources can’t meet the rapid growth of oil demand, people began turning to unconventional oil resources, one of which is the oil sands. Oil sands is unconventional oil resources, if its proven reserves are converted into oil, it will be much larger than the world's proven oil reserves. Canadian oil sands reserves stand ahead in the world, followed by the former Soviet Union, Venezuela, the United States and China. However, due to its special properties, different mining and processing technology, and higher mining costs compared with conventional oil, the research of oil sands makes slow progress. At present, due to the rising of world oil price, oil sands mining technology have attracted more and more attention, and have developed a lot.

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.

Sign in / Sign up

Export Citation Format

Share Document