Rheological Properties of Fresh Cemented Paste Tailings

Sofrà, Fiona

doi:10.1007/978-3-319-39682-8_3

Cited by 15 publications

(12 citation statements)

References 15 publications

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“…Many previous studies show that the combination of CTAB and NaSal enhances the phenomena of slip due to the formation and fracture of shear‐induced structures (SISs) at low

\overset{γ}{true}

. The heavy benzene ring of the salicylate ion penetrates beyond the head group area of the CTAB micelle (Figure ), resulting in an increase in the average volume per CTAB molecule and a decrease in the effective area of CTAB head group.…”

Section: Resultsmentioning

confidence: 99%

Influence of additives, particle size, and incorporation of coarse particles on the shear rheology of concentrated Indian coal ash slurries

Prasad

Mehrotra

Thareja

2019

Asia-Pacific J Chem Eng

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The aim of this study is to first obtain stable coal ash slurries using additives and understand their flow behaviour as a function of the size of coal ash particles and incorporation of coarse coal ash particles. The combination of 0.1 wt% cationic surfactant cetyltrimethyl ammonium bromide (CTAB) and 0.1 wt% sodium salicylate (NaSal) salt is used to stabilize the coal ash slurries with 60 wt% coal ash loading. The range of shear rate (_ γ) of 10-500 s −1 is determined to be free from the artefacts of slip and Taylor vortices and, hence, found to be reliable for rheological measurements. The slurries show predominantly shear thinning flow behaviour irrespective of the size of coal ash particles. We also show that the viscosity of the slurries increases monotonically with the decrease in the size of coal ash particles. The incorporation of coarse coal ash particles results in a decrease in the viscosity until a critical coarse particle concentration of 30 wt% is reached, beyond which no significant change in viscosity is observed.

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“…Many previous studies show that the combination of CTAB and NaSal enhances the phenomena of slip due to the formation and fracture of shear‐induced structures (SISs) at low

\overset{γ}{true}

Section: Resultsmentioning

confidence: 99%

Influence of additives, particle size, and incorporation of coarse particles on the shear rheology of concentrated Indian coal ash slurries

Prasad

Mehrotra

Thareja

2019

Asia-Pacific J Chem Eng

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“…From a single-point measurement (the maximum torque), the yield stress of the prepared thickened tailings can be determined [20]. It was found that the yield stress was about 63 Pa which is considered related to the characteristic of the thickened tailings as stated, for example, by Sofra [76]. This amount of yield stress was equivalent to a solid content of about 70%.…”

Section: Preparation Of the Thickened Tailingsmentioning

confidence: 99%

“…TTs have more solids content by weight compared with the slurry tailings as well as can be pumped as in the case of slurry tailings [17]. The solid content in thickened tailings is ranged between 50 and 70% with a yield stress of between 30 and 100 Pa [31,76]. Unlike slurry tailings during the deposition, the segregation of thickened tailings does not occur since the mass of thickened tailings has a homogenous behaviour with low permeability [67].…”

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confidence: 99%

Dynamic response of thickened tailings in shaking table testing

Alshawmar

Fall

2021

Geo-Engineering

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In this study, an instrumented thickened tailings deposit model was designed, built and employed to evaluate the behaviour of layered thickened tailings to dynamic loading by using a shaking table equipment. The thickened tailings were deposited subsequently in three thin layers in a flexible laminar shear box mounted on top of the shaking table. Cyclic loading with a peak horizontal acceleration of 0.13 g and a frequency of 1 Hz was applied to the layered tailings deposit. Different types of sensors were placed to monitor the accelerations, displacements, volumetric water content and pore water pressures at the intermediate depth of each layer. Results indicated that the acceleration for the bottom and middle layers were similar to that of the base of the shaking table; but, this was not the case for the top layer. The measurements of vertical displacements indicated that all layers of thickened tailings experienced initially contraction and subsequently dilation during the shaking. The excess pore water pressure ratios were found to exceed unity through all layers of thickened tailings when the shaking ended. In other words, the results showed that the layered thickened tailings are susceptible to liquefaction under the considered testing conditions. It is also found that upward pore water migration to the top layer and downward pore water flow to the bottom layer occurred in the thickened tailings deposit. This water migration generated additional pore water pressure and also impacted the vertical displacement and liquefaction susceptibility of the thickened tailings material. The results of this study give a better understanding of the dynamic behaviour of thickened tailings, which is crucial for the safety of thickened tailings systems as well as sustainable mining.

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“…As yield stress is positively correlated with the solid content of the fill, e.g. the higher the solid content, the higher the yield stress (Silva 2017;Sofra 2017), increasing the solid content of the fill is expected to have an effect on the pumping pressure within the reticulation system of the mine. However, actual pressure data from the mines could show that this is not necessarily the case.…”

Section: Introductionmentioning

confidence: 99%

Efficient paste mix designs using new generation backfill admixtures: perception versus reality

Erismann¹,

Hansson²

2020

Proceedings of the Second International Conference on Underground Mining Technology

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Backfilling mined out stopes with cemented paste has become the standard in most modern, long-hole stoping and cut-and-fill operations globally. The implementation of large-scale paste production plants and efficient underground paste reticulation systems contributed significantly to maximised ore extraction, higher levels of mine-scale geotechnical stability, larger degree of automation and last, but not least, to a more conscious management of mine processing waste. However, paste backfilling comes at a cost. Binder costs alone amount to 70-80% of total operating costs of paste plants depending on the strength requirements and characteristics of tailings used for backfilling and it is not uncommon that underground paste filling contributes up to 20% of the overall cost structure of an underground operation. With a view towards improving the paste mix designs and keeping cement consumption under control, new generation paste backfill admixtures have been developed over the past years. The mine backfill industry can be compared to the concrete industry 40 years ago, when high performance admixtures started to emerge for landmark projects, where exceptionally high concrete qualities and specific, fresh concrete properties were required (Aitcin & Wilson 2015). These high range water reducers quickly transformed the construction industry and pushed concrete applications to new, previously unknown limits. This paper intends to give an overview of the reality of admixtures in the mine backfill industry and their performance and justification in modern paste backfill plants with pump driven reticulation systems. Data from different paste plants around the globe has been compiled for this study, covering different deposit types, strength requirements and pumped paste mix designs. The study illustrates the powerful effect paste backfill admixtures can have on standard paste mix designs and their potential to reduce binder consumption substantially by remaining within the required strength and workability limits of the paste to improve the overall cost structure of backfill operations.

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Rheological Properties of Fresh Cemented Paste Tailings

Cited by 15 publications

References 15 publications

Influence of additives, particle size, and incorporation of coarse particles on the shear rheology of concentrated Indian coal ash slurries

Influence of additives, particle size, and incorporation of coarse particles on the shear rheology of concentrated Indian coal ash slurries

Dynamic response of thickened tailings in shaking table testing

Efficient paste mix designs using new generation backfill admixtures: perception versus reality

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