Evaporation, Unsaturated Flow, and Salt Accumulation in Multilayer Deposits of “Paste” Gold Tailings

Fisseha, Bereket; Bryan, Rachel; Simms, Paul

doi:10.1061/(asce)gt.1943-5606.0000367

Cited by 49 publications

(35 citation statements)

References 18 publications

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“…This decline may be accelerated by high salinity (or high concentrations of dissolved mass in the pore water) -as salinity decreases evaporation by multiple mechanisms of osmotic suction, high albedo (reflectivity to shortwave radiation), and formation of a salt crust Dunmola 2012). While cracking does occur, the frequency and size of the cracks appear insufficient to substantially increase evaporation in low-plasticity hard rock tailings (Simms et al 2007;Fisseha et al 2010;Daliri et al 2016). In tailings with significant clay content, however, cracking appears to be a very important mechanism to maintain relatively high evaporation rates.…”

Section: Evaporationmentioning

confidence: 99%

“…For hard rock thickened tailings of low plasticity, the evaporation rate follows classic soil drying (Simms et al 2007;Fisseha et al 2010;Daliri et al 2016), where evaporation decreases with time after deposition of fresh tailings. This decline may be accelerated by high salinity (or high concentrations of dissolved mass in the pore water) -as salinity decreases evaporation by multiple mechanisms of osmotic suction, high albedo (reflectivity to shortwave radiation), and formation of a salt crust Dunmola 2012).…”

Section: Evaporationmentioning

confidence: 99%

“…No model can handle stress history effects; in other words, none have memory, which is important for the case of multi-layer deposition, where both volume change as well as wet-dry hysteresis may be important. Simms et al (2010) and Fisseha et al (2010) implemented a modelling methodology involving unsaturated flow to handle volume change hysteresis that appears to work well for hard rock tailings, but it does not consider large-strain consolidation and therefore is limited in its application to all tailings types. Qi et al (2017) incorporated an unsaturated formulation based on Vu (2002) into a piecewise linear formulation of large-strain consolidation that was partially verified using the results of Seneviratne et al (1996).…”

Section: Generalized Modelling Of Dewatering Of High-density Tailingsmentioning

confidence: 99%

“…Thickened and even paste tailings will exhibit some degree of sedimentation or self-weight consolidation within hours to days after deposition, even when deposited in quite thin lifts (Daliri et al 2015;Fisseha et al 2010;Simms et al 2007). For hard rock tailings, the initial sedimentation or self-weight consolidation can occur within 2-3 days (Dunmola 2012;Simms et al 2007).…”

Section: Sedimentation and Self-weight Consolidation In A Thin Liftmentioning

confidence: 99%

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

Simms

2017

Can. Geotech. J.

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Abstract:The breaching of containment of conventionally deposited mine tailings impoundments, and the consequent release of tailings flows with long run-outs, unfortunately remains not uncommon and often has devastating ecological and economic consequences, occasionally including the loss of human life. Rather than the breaching of containment itself, which can result from a number of causes (poor control of the phreatic surface, unrecognized dam foundation issues), the contributing factor to the severe consequences of dam breach is the low density and strength and (or) susceptibility of the tailings to liquefy or soften under loading, combined with the driving weight of the ponded water, which allows for significant run-outs (in some cases tens of kilometres) to occur. Hence the motivation for developing alternative technologies that dewater tailings before deposition to the point where reliance on containment is minimized or eliminated. In this paper, these technologies are referred to as "high-density" tailings, which includes any technology that at least produces nonsegregating tailings that will form a sloped stack when deposited, including thickened, paste, and filtered tailings. The paper explores a number of issues related to high-density tailings, including shear behaviour, dewatering behaviour, acid generation, and surface deposition rheology. The paper concludes with some discussion on what the limitations are on this technology that are holding back its wider adoption, and how these limitations might be overcome.Key words: tailings, thickened, paste, filtered, high density.Résumé : La rupture du confinement de déversement de résidus de mines déposés de manière conventionnelle, et par conséquent, des rejets de flux de résidus à long terme, ne demeure malheureusement pas rare et souvent a des conséquences dévastatrices écologiques et économiques, à l'occasion, y compris la perte de vie humaine. Plutôt que la rupture du confinement même, ce qui peut résulter d'un certain nombre de causes (mauvais contrôle de la nappe phréatique, problèmes de fondation de barrage non reconnus), le facteur qui contribue à de graves conséquences de rupture de barrages est la faible densité et la résistance et (ou) la sensibilité des résidus à se liquéfier ou à se ramollir sous chargement, combiné avec le poids de charge de l'eau accumulée, qui permet des rejets (dans certains cas de dizaines de kilomètres) à se produire. D'où la motivation pour developper des technologies alternatives permettant d'assécher les résidus avant le dépôt au point où le recours au confinement est réduit ou éliminé. Dans cet article, ces technologies sont considérées comme des résidus de « haute densité », qui comprend toute technologie qu'au moins produit des résidus sans ségrégation qui forment une pile en pente, lorsque déposés, y compris des résidus épaissis, en forme de pâte, et filtrés. L'article explore un certain nombre d'enjeux liés à des résidus à haute densité, y compris le comportement en cisaillement, le comportement à l'assèchement,...

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Section: Evaporationmentioning

confidence: 99%

Section: Evaporationmentioning

confidence: 99%

Section: Generalized Modelling Of Dewatering Of High-density Tailingsmentioning

confidence: 99%

Section: Sedimentation and Self-weight Consolidation In A Thin Liftmentioning

confidence: 99%

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

Simms

2017

Can. Geotech. J.

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“…The water-retention curves were determined using the axis-translation technique with sample volume measurement in a 'Fredlund' soil water characteristic curve (SWCC) device from GCTS for matric suction values less than 500 kPa, while drier samples were analysed using a WP4 hygrometer for total suction (Leong et al, 2003). The axistranslation technique with volume change was performed as first described by Fisseha et al (2010). Vertical volume change is estimated using non-contact ultrasonic displacement sensors, between each stage in the axis-translation test, while crack volumes are estimated by hand measurements using callipers.…”

Section: Methodsmentioning

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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Proper Adhesive Choice Increases Photothermal Float Durability in Mine Water Disposal Applications

Monasmith

Zodrow

2020

Mine Water Environ

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Evaporation, Unsaturated Flow, and Salt Accumulation in Multilayer Deposits of “Paste” Gold Tailings

Cited by 49 publications

References 18 publications

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

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

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

Proper Adhesive Choice Increases Photothermal Float Durability in Mine Water Disposal Applications

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