Characterization of a gold tailings with hypersaline pore fluid

Reid, Donald B.; Fourie, Andy; Moggach, Stephen A.

doi:10.1139/cgj-2018-0579

Cited by 14 publications

(5 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Plewes Method indicates a quite loose state within the sampled depth range of 7.0 to 8.8m, with Ψ values of +0.10 to +0.20. This is consistent with this area having historically undergone subaqueous deposition, which tends to result in extremely loose states (Shuttle and Cunning 2007;Reid and Jefferies 2017;Reid et al 2018;Reid et al 2019). Outside of this particular zone of subaqueous deposition, Ψ ranges between about -0.05 and +0.10, which is a range more consistent (e.g.…”

Section: Cpt Interpretationsupporting

confidence: 82%

The effect of tamping conditions on undrained shear strengths of a non-plastic sandy silt tailings

Reid

Fanni

DiDonna³

2022

Can. Geotech. J.

Self Cite

View full text Add to dashboard Cite

A series of direct simple shear (DSS) tests were carried out on a non-plastic sandy silt lead−zinc−silver tailings to develop a relationship between undrained shearing behaviour and density for contractive states. The critical state line was also obtained through triaxial compression tests to enable the DSS tests to be viewed in a critical state framework and allow comparison with in situ testing. It was found that the gravimetric water content (GWC) used to tamp the specimens had a significant effect on the resulting undrained strengths when attempting to achieve dense states — with higher GWC giving lower strength at a given density than a lower GWC. Intact and slurry deposited (SD) samples were also tested to access denser states without inducing tamping-related stresses. These showed a more consistent trend with the loose-tamped specimens, and with other data from the literature. Plausible explanations as to the causes of the increased strength of dense-tamped samples were obtained through estimating potential preconsolidation stresses and “locked in” horizontal stresses that may occur from dense tamping. The importance of these observations on the development of density−strength profiles in engineering practice was outlined.

show abstract

Section: Cpt Interpretationsupporting

confidence: 82%

The effect of tamping conditions on undrained shear strengths of a non-plastic sandy silt tailings

Reid

Fanni

DiDonna³

2022

Can. Geotech. J.

Self Cite

View full text Add to dashboard Cite

show abstract

“…where U ni is the percent undercompaction selected for the first bottom layer, and U nt is the percent undercompaction for the final top layer (usually zero); n t is the total number of layers, and n is the selected layer (note that the first layer to be compacted is the bottom one, which will correspond to n = 1). Although widely used, techniques to establish what value of U ni should be adopted do not appear to have achieved a consensus [73]. The authors will further present their recommendations for the values of U ni .…”

Section: Moist Tamping Technique and Undercompaction Methodsmentioning

confidence: 99%

“…Since this procedure aims to achieve a full saturation condition, the use of de-aired water inside the specimen is essential, as most of the dissolved gas (mixture of air and CO 2 ) present in the fluid was already removed. However, if the material tested contains some dissolved solids (such as salt), deionised water should be used instead to avoid any pore fluid chemistry issues affecting the CSL definition [73].…”

Section: Water Flushingmentioning

confidence: 99%

Recommended Procedures to Assess Critical State Locus from Triaxial Tests in Cohesionless Remoulded Samples

2021

View full text Add to dashboard Cite

The critical state theory is a robust conceptual framework for the characterisation of soil behaviour. In the laboratory, triaxial tests are used to assess the critical state locus. In the last decades, the equipment and testing procedures for soil characterisation, within the critical state framework, have advanced to obtain accurate and reliable results. This review paper summarises and describes a series of recommended laboratory procedures to assess the critical state locus in cohesionless soils. For this purpose, results obtained in the laboratory from different cohesionless soils and triaxial equipment configurations are compiled, analysed and discussed in detail. The procedures presented in this paper reinforce the use of triaxial cells with lubricated end platens and an embedded connection piston into the top-cap, together with the verification of the full saturation condition and the measurement end-of-test water content—preferable using the soil freezing technique. The experimental evidence and comparison between equipment configurations provide relevant insights about the laboratory procedures for obtaining a reliable characterisation of the critical state locus of cohesionless geomaterials. All the procedures recommended herein can be easily implemented in academic and commercial geotechnical laboratories.

show abstract

“…Although clearly a thickened tailings deposit would seek to avoid deposition into water, it is not uncommon for perimeter raising requirements of some thickened deposits to result in perimeter wall construction and raising, with supernatant water then reporting to channels and ponds that form against the wall. Whatever the mechanism, it is clear that no slurry-based sample preparation technique, regardless of the measures taken to minimise disturbance during preparation, could be prepared to loose states such as may result from uncompacted placement on a filter deposit or quiescent subaqueous deposition, with this issue as it related to subaqueous deposition having received the most study and discussion (Shuttle & Cunning 2007;Reid & Jefferies 2017Reid et al , 2019Reid 2021).…”

Section: Figure 5 Synthesis Of Slurry Consolidometer and Sd Triaxial Consolidation Datamentioning

confidence: 99%

Some considerations when preparing thickened tailings for shear strength testing in the laboratory from a slurry

Reid¹,

Fanni²,

Fourie³

2021

Proceedings of the International Seminar on Paste and Thickened Tailings

Self Cite

View full text Add to dashboard Cite

Preparation of tailings in the laboratory to simulate the likely range of densities and resulting behaviour that will occur under load in situ is challenging. A number of issues of relevance include whether effects such as subaqueous deposition can be reproduced at all in the laboratory, and the potential importance of in situ layering of segregating tailings. These issues may have (thus far, largely unquantified) effects on mechanical behaviour in ways that are difficult to predict with element tests that are usually intentionally prepared homogeneously. Thickened tailings testing is conceptually easier, as issues such as segregation and the potential for subaqueous deposition are often not relevant. Despite this relative simplicity, a number of important considerations remain. While it is trivial to pour a thickened slurry into various forms of moulds or vessels to prepare for element testing, questions remain over whether the density that is reproduced will be relevant to in situ conditions. In particular, preparation of triaxial samples from thick slurries is particularly challenging as a number of steps are required to enable such samples to be 'free-standing', with each one of these steps potentially leading to slight disturbance and thus densification of the sample. Where such densification occurs, it would result in the element test results being non-conservative. This could have important implications with respect to expectations of the contractive (and potentially liquefiable) or dilative response of the tailings in situ.To investigate these issues, a series of slurry-deposited triaxial tests was carried out using a non-segregating slurry. As test methods were refined during the program, the amount of disturbance applied to the specimen was reduced. However, comparison of the triaxial tests to slurry consolidometer tests indicated that, regardless of efforts made, the triaxial tests achieved denser states at a given amount of consolidation stress. This was found to be the case using any conceivable range of assumed geostatic stress ratio to interpret the slurry consolidometer results. This outcome is speculated to be a result of the quiescent conditions used in the preparation of a slurry consolidometer specimen, which only requires pouring and then application of vertical load, first using weights, then a load frame. The implications of the increased density seen in triaxial tests compared to the likely more realistic value seen from the slurry consolidometer are discussed. Alternative preparation methods to target this looser density range are briefly discussed.

show abstract

Characterization of a gold tailings with hypersaline pore fluid

Cited by 14 publications

References 47 publications

The effect of tamping conditions on undrained shear strengths of a non-plastic sandy silt tailings

The effect of tamping conditions on undrained shear strengths of a non-plastic sandy silt tailings

Recommended Procedures to Assess Critical State Locus from Triaxial Tests in Cohesionless Remoulded Samples

Some considerations when preparing thickened tailings for shear strength testing in the laboratory from a slurry

Contact Info

Product

Resources

About