2013 Colloquium of the Canadian Geotechnical Society: Geotechnical and geoenvironmental behaviour of high-density tailings

Simms, Paul

doi:10.1139/cgj-2015-0533

Cited by 27 publications

(13 citation statements)

References 44 publications

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“…Again, this is because self-weight consolidation occurs so rapidly there is no evaporative potential lost because of the bleed water, following the model assumption that excess bleed water runs off the tailings. The void ratio trends after self-weight consolidation for winter or summer deposition conform to field measurements in wet or dry seasons reported at some sites in a similar climate (Kam et al 2014;Simms 2016).…”

Section: Gold Tailingssupporting

confidence: 85%

Analysis of dewatering and desaturation of generic field deposition scenarios for thickened tailings

Qi¹,

Simms²

2018

Proceedings of the 21st International Seminar on Paste and Thickened Tailings

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Models that compute dewatering using accurate coupling of evaporation, unsaturated flow and large strain consolidation may have utility in providing guidance to optimise deposition of thickened tailings. A recently developed research model, UNSATCON, is used to analyse some typical field deposition profiles for both hard rock and oil sands fine tailings deposits. Model parameters are selected from previous studies on hard rock and oil sands tailings. Some validation with select field data is presented. Exploratory analysis reveals a number of interesting findings. For hard rock tailings, where self-weight consolidation after lift placement occurs relatively quickly due to high hydraulic conductivity of the tailings, maximisation of density can be achieved for a wide range of lift thickness and rates of rise even with relatively low rates of evaporation. For desaturation and risk of oxidation, lift thickness and deposition timing become more important. For oil sands tailings, the timing of deposition and lift thickness are more important for maximising density due to the much lower hydraulic conductivity and, therefore, the longer time of self-weight consolidation.

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Section: Gold Tailingssupporting

confidence: 85%

Analysis of dewatering and desaturation of generic field deposition scenarios for thickened tailings

Qi¹,

Simms²

2018

Proceedings of the 21st International Seminar on Paste and Thickened Tailings

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“…7 During pipeline transportation, when the tailings are subjected to pressure gradients, they must have sufficient fines to allow flow without particle segregation: the rule of thumb is 15% of the particles should have diameters < 20 μm. 23 ST are classified as either "wet" cake (∼100% saturation) or "dry" cake (∼70−85% saturation). ST can be transported by conveyors or trucks and then spread, layered, and compacted onto drying pans to form unsaturated, dense, and stable stacks requiring a small dam or dike for retention.…”

Section: Dewatered Tailingsmentioning

confidence: 99%

“…Typically, thickened tailings are transported by centrifugal pumps, whereas paste tailings are transported using positive displacement pumps with high-pressure piping . During pipeline transportation, when the tailings are subjected to pressure gradients, they must have sufficient fines to allow flow without particle segregation: the rule of thumb is 15% of the particles should have diameters < 20 μm …”

Section: Dewatered Tailingsmentioning

confidence: 99%

Dewatered and Stacked Mine Tailings: A Review

et al. 2022

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Tailings storage is a prescient issue in mining, representing a visible and destructive liability. Dewatering tailings to a paste-like consistency is a popular option to reduce tailings volumes and increase dam safety, but dewatering further to a bulk cake consistency has mostly been reserved for small operations in locations where seismicity or terrain prohibited the construction of dams. The recent high-profile failures of tailings dams such at Fundão and Brumadinho facilities along with the push toward socially conscious investing have generated renewed and urgent interest in tailings dewatering, including stacked (“filtered” or “dry-stack”) tailings. While geochemistry and civil engineering topics relating to tailings in general are both extensively studied, very little academic literature is available specifically on stacked tailings, with discussion mostly confined to conference articles or extrapolation about the behavior of dewatered tailings. Furthermore, the nomenclature around and definition of this method of tailings storage is inconsistent, which can make researching the topic unnecessarily tedious and confusing and, in the worst case, can open the door to intentional misrepresentation of a tailings storage facility’s safety as this is a technology still being scaled up. In this article, the term stacked tailings (ST) is introduced to describe what has been otherwise called filtered tailings or dry-stack(ed) tailings to remedy the inaccuracies with the two existing names and gather the existing literature in one place. Topics covered include the existing definitions of dewatered and stacked tailings; opportunities and barriers to adoption; and construction and general operation for such tailings storage facilities. These are supplemented by an overview of literature in geotechnical and geochemical topics relevant to tailings dewatering (ex. clays) and tailings storage facilities. Emerging dewatering technologies and innovations which might be useful in the scaling up of the technology are also discussed. The aim is to provide a thorough background on the topic for a general audience, outline gaps in the literature, and encourage further exploration of stacked tailings and tailings cake by furnishing a comprehensive list of sources. Stacked tailings are discussed in a rigorous way to make the topic a more approachable way to encourage standardization and adoption, scale up, and the development of associated technologies.

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“…The aluminium industry relies heavily on evaporation to stabilise 'red muds' (Doucet and Paradis, 2010), while thickened tailings deposition in a variety of climates takes advantage of evaporation to reduce tailings volumes (Simms, 2016). Certain tailings management methods in the Canadian oil sands industry, such as Suncor's tailings reduction operations (Caldwell et al, 2014) and Shell's atmospheric fine drying technologies , use evaporation to reduce tailings volumes.…”

Section: Introductionmentioning

confidence: 99%

Cracking, salinity and evaporation in mesoscale experiments on three types of tailings

Simms

SoleimaniSahar

MizaniShabnam

et al. 2019

Environmental Geotechnics

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Evaporation is a phenomenon useful in assisting in the dewatering and stabilisation of various mineral wastes. This paper summarises findings on the influence of cracking and salinity on evaporation in mesoscale (1·0 m by 0·7 m in plan) deposition experiments on three different mineral slurries: thickened gold tailings, thickened oil sands tailings and oil sands tailings modified by in-line polymer flocculation. Each tailings exhibited substantially different evaporation related phenomena. In the two finer-grained oil sands tailings, crack development correlated with apparent actual evaporation rates larger than the potential rate, which ceased once crack volume stopped increasing. Total suction at the surface was dominated by osmotic suction in the thickened oil sands tailings, whereas total suction was largely matric in the other two tailings. In the gold tailings, no strong signal from cracks on evaporation could be detected. The gold tailings exhibited 'declining stage I' evaporation, which has been recently described from idealised drying experiments on sands. The relatively unique behaviour of each tailings type with respect to evaporation highlights the importance of considering larger scale effects when assessing tailing dewatering by evaporation. NotationA E actual evaporation (mm/d) A EV air entry value (kPa) a soil-dependent parameter in the soil surface resistance equation C a specific heat of air (MJ/(kg°C)) D xx percent (%) of particles less than XX microns in size G flux of heat into the soil away from the soil surface (MJ/(m 2 d))L L liquid limit (%) P E potential evaporation (mm/d) P L plastic limit (%) R universal gas content R E relative evaporation R H relative humidity R Ha relative humidity of the air above the evaporating surface R n net short and long wave radiation (MJ/(m 2 d)) r a density of air (kg/m 3 )r s , r a soil surface and aerodynamic resistance factors S L shrinkage limit (%) T temperature (K) v s , v a vapour pressures at the soil surface and in the air (kPa) W molecular weight of water (kg/mol) w geotechnical gravimetric water content (%) g psychometric constant (kPa/°C) D slope of vapour pressure-temperature relationship (kPa/°C) q ref reference volumetric water content at an arbitrary depth used to calculate soil surface resistance factor q top actual water content at the same depth as the reference volumetric water content L latent heat of evaporation (MJ/kg) y total suction (kPa) IntroductionDrying tailings to increase density and strength is often used to assist stabilisation and reclamation of tailings impoundments. The aluminium industry relies heavily on evaporation to stabilise 'red muds' (Doucet and Paradis, 2010), while thickened tailings deposition in a variety of climates takes advantage of evaporation to reduce tailings volumes (Simms, 2016). Certain tailings management methods in the Canadian oil sands industry, such as Suncor's tailings reduction operations (Caldwell et al., 2014) and Shell's atmospheric fine drying technologies , use evaporation to reduce tai...

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2013 Colloquium of the Canadian Geotechnical Society: Geotechnical and geoenvironmental behaviour of high-density tailings

Cited by 27 publications

References 44 publications

Analysis of dewatering and desaturation of generic field deposition scenarios for thickened tailings

Analysis of dewatering and desaturation of generic field deposition scenarios for thickened tailings

Dewatered and Stacked Mine Tailings: A Review

Cracking, salinity and evaporation in mesoscale experiments on three types of tailings

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