What’s going on in there?

Pullum, Lionel

doi:10.36487/acg_rep/1104_34_pullum

Cited by 5 publications

(8 citation statements)

References 25 publications

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“…In a review, Pullum (2007) considered high Cw-values of 85-88% and used the term Ultra High Concentration (UHC), referring to low friction loss test results with coarse coal with initial lack of fines for a pump of rotary ram type with valve arrangements (see also Pullum et al 1996). UHC is where packing can be so close that particles may not reorganise in the pipe, and inter-particle motion is limited.…”

Section: Hydraulic Characterisationmentioning

confidence: 99%

Loop pumping tests of crushed rock mixed with thickened tailings

Wennberg¹,

Stalnacke²,

Sellgren³

2023

Paste 2023: 25th International Conference on Paste, Thickened and Filtered Tailings

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LKAB operates three mines in northern Sweden, where the climate is subarctic with an average temperature of about 0 o C. LKAB's long-term overall objective includes feasibility considerations of thickened or filtered tailings combined with waste rock co-disposal covering cyclic economy considerations and landscape forming. At the Kiruna underground mine, about 3.5 Mtonnes of tailings and 12 Mtonnes of waste rock are generated annually. Crushing to less than 30 mm is part of the sorting plant processing, and the rock is deposited in stockpiles while the tailings are pumped conventionally to water-holding impoundments.The aim is to indicatively test the pipeline pumping of paste-rock mixtures at solids concentrations by weight of over 85% to limit segregation and leakage during deposition in nearby old pit holes. A test was carried out at a paste thickener with direct access to fresh paste, which was mixed in a concrete mixer with crushed rock from the processing. A 38 m long loop with a pipeline inner diameter of 0.075 m was equipped with a concrete type of pump. Unfortunately, a second test in a larger pipe could not be carried out at the planned time. LKAB then had the opportunity to test a laboratory-scale concrete industry device, the sliding pipe rheometer, Sliper, developed to simulate concrete pipeline pumping frictional resistance in a 0.126 m diameter pipeline. Initial loop results with crushed rock particles of up to 10 mm with a rock-to-paste mass ratio R:P of 1.2:1 showed a pressure requirement of about 25 kPa/m at 0.

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Section: Hydraulic Characterisationmentioning

confidence: 99%

Loop pumping tests of crushed rock mixed with thickened tailings

Wennberg¹,

Stalnacke²,

Sellgren³

2023

Paste 2023: 25th International Conference on Paste, Thickened and Filtered Tailings

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“…The material was first pre-sheared (to de-structure the material) at a constant shear rate of 100 ƒ -1 for 90 seconds, then allowed to stand for 15 seconds and, finally, subjected to decreasing shear rate steps from 100 to 0 ƒ -1 for 70 seconds. Even if thixotropy can be observed for PT and CPB, it should be mentioned that rheological properties determined on the flow and viscosity curves obtained in descending mode are suitable for the design of the flow in CPB pipelines (Pullum 2007). The thermal properties measurement of PT and CPB mixtures was then performed using the SH-1 thermal probe of the KD2-Pro thermal analyser.…”

Section: Rheological and Thermal Characterisation Of Pt And Cpb Mixturesmentioning

confidence: 99%

Numerical procedure for scaling up pressure loss from mini flow loop tests

Kalonji¹,

Mbonimpa²,

Belem³

et al. 2023

Paste 2023: 25th International Conference on Paste, Thickened and Filtered Tailings

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Although in the literature friction factors have been developed specifically for Newtonian and non-Newtonian fluids to predict pressure loss during pipeline flow, their use for cemented paste backfills (CPB) still needs to be validated. For backfilling system feasibility studies, the flowability, pump selection and pumping requirement can be assessed through flow loop tests using full diameter (Dfull) pipeline arrangement. At the laboratory scale, only small flow loop tests using small diameter (Dsmall = Dloop) pipeline arrangement can be conducted. However, as the pressure loss (∆p/L) is closely dependent on the pipeline inner diameter (Di), ∆p/L measured from a small flow loop test must be correctly scaled to the field pipeline diameter (Dfield = Dfull). The objective of this paper is to present a numerical simulations-based procedure for scaling up pressure loss from small flow loop tests. For this purpose, small flow loop tests were conducted using a 27.9 m-long pipeline circuit arrangement. The small pipe's inner diameter (Dloop) was 0.0318 m. The pipeline circuit was instrumented with temperature probes (thermocouple) and a differential pressure meter for monitoring the evolution of the CPB temperature and pressure loss, respectively. After calibrating the non-isothermal pipe flow model in COMSOL Multiphysics ® 5.2 software using temperature and pressure loss data gathered from the small flow loop tests, numerical simulations of flow loop tests were conducted to consider various filled inner diameters (Di) of pipes from 0.05 to 0.2 m) while keeping the rheological and thermal properties of the CPB unchanged. Results indicate a negative power law relationship between the pressure loss ratio and the inner diameter ratio (Di/Dloop). Work is still underway to verify if this relationship applies for different CPB mix recipes and different temperature conditions.

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“…5. Cooke (2002), Pullum (2007) and others have dealt with this problem in some detail. For non-Newtonian slurries in pipelines, the applied stress must be greater than the slurry yield stress for the material to flow.…”

Section: Understanding Settling Problemsmentioning

confidence: 99%

“…These are the systems that are more prone to blockage. Researches done by Thomas (1979), Gillies et al (1999) and Pullum (2007) and others suggest that for a specific slurry, there is a minimum pipeline pressure gradient needed to transport all the solids in the pipeline. Provided that there is sufficient force across the settled bed, the solids will slide along the invert.…”

Section: Understanding Settling Problemsmentioning

confidence: 99%

“…Figure 7 (Pullum, 2007) shows that as pipe diameter increases, for a constant dry tonnage, the expected pressure loss for a homogenous flow will decrease as the slurry solids concentration decreases. If the flow is stratified, then this is clearly not the case and, as pipe diameter increases, the pressure gradient is more or less constant as the solids settle on the pipe invert and are transported as a sliding bed.…”

Section: Understanding Settling Problemsmentioning

confidence: 99%

See 1 more Smart Citation

Pipeline transport of high density slurries: a historical review of past mistakes, lessons learned and current technologies

Paterson

2012

Mining Technology

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There is a great deal of misinformation in the industry on pumping high density, viscous slurries. These misconceptions become 'accepted truths' as time goes on which, at best hinder, and at worst, stop the implementation of appropriate technology. Unfortunately, the root of these misconceptions is often due to negative experiences gained on poorly understood, poorly designed or poorly implemented systems. Advances in a technology can only be realised by accepting that the mistakes of the past can be rectified and learned from. Unfortunately, this does not readily happen in an industry that is resistant to change. The objective of this paper is to address these issues by tracing the historical development of high density pumping and why the problems of the past are not necessarily the same problems that we experience today. It is accepted that many of the fundamental problems cannot be resolved and continued improvements in ore processing will mean that new challenges will arise. However, there is a better understanding of how to deal with the issues practically, by using the latest developments in pump and pipeline technology.

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What’s going on in there?

Cited by 5 publications

References 25 publications

Loop pumping tests of crushed rock mixed with thickened tailings

Loop pumping tests of crushed rock mixed with thickened tailings

Numerical procedure for scaling up pressure loss from mini flow loop tests

Pipeline transport of high density slurries: a historical review of past mistakes, lessons learned and current technologies

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