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An exploratory study demonstrated that subtle changes in solids and process water were caused by long-distance turbulent transport of tailings from the concentrator to the impoundment of a Cu (Mo) porphyry copper deposit. Slurry water chemical analysis was complemented by modelling potential phase precipitation or dissolution and speciation of dissolved metals. It was found that transport did not affect major insoluble mineral phases. However, the degrees of liberation of several phyllosilicates, as determined by automated mineralogy, were reduced close to the impoundment, which points to separation of clay particles from tectosilicate surfaces by the turbulence; this also was observed by SEM examination of micro-aggregate specimens. Reduction of maximum particle sizes, increased N2 monolayer adsorption, and resultant specific surface areas indicate that transport modified the micro-aggregates. Major element water chemistry is controlled by the presence of soluble mineral phases, such as gypsum, and reagents, such as lime, in the flotation process. Changes in the dissolved concentrations of some elements could potentially affect tailings deportment in the impoundment. Increased concentrations of Al may affect the clay settling behaviour, while Mo and As levels will require treatment prior to the discharge of water from the tailings impoundment. This study demonstrated that systematic scrutiny of tailings slurries leaving the concentrator and before entering the impoundment can be potentially useful, though care will have to be exercised to replicate sample handling and analytical conditions, during any long-term monitoring.

Prediction of horizontal pressure drop in dilute phase pneumatic conveying or slurry transport is among the fundamental issues of designing these systems. In this work a thorough literature survey demonstrates that there is no consensus on an integrative solution for conveying pressure drop, therefore a large data base of conveying systems' operating points at dilute phase is established and analyzed. It includes measurements taken at our 52 mm bore laboratory pneumatic conveying line, as well as thousands of data points collected from the literature. Two modelling approaches are attempted – the first is frictional representation based on dimensional analysis, which presents linear dependency between the pressure drop and the superficial fluid velocity normalized by the minimum pressure velocity of the transport curve. It had also been found that the pressure drop increase rate has a strong dependency on the Archimedes number. The second approach is an energy balance between the power of the drag force applied to the particles and the additional power required to drive the fluid due to particle presence. Unlike the common expressions, a modification to the drag coefficient is suggested, which takes into account pipe turbulence and particle acceleration. The two presented models do not require pilot plant calibration, and an applicability of one of them to slurry transport is demonstrated. Some future research routes are offered.

Extensive work was carried out to improve the performance of cast irons used for slurry transport in the oil sands industry. Because of complex condition of the multi-phase fluid containing oil sand particles, erosion-corrosion damage has long been an issue. High chromium cast irons (HCCIs) are currently used for slurry pumps, showing high resistance to sand-containing slurry erosion. However, further enhanced HCCIs are highly desired in order to more effectively reduce the damage to oil sand slurry transport facilities caused by erosion-corrosion for prolonged service life. This study was focused on tailoring an existing HCCI used in the oil sands industry by adding trace boron. Microstructure and relevant properties of the modified cast irons were characterized and evaluated. It was demonstrated that trace boron markedly increased the resistance of the cast iron to slurry erosion. The mechanism responsible for the improvement was analyzed based on observed variations in microstructure and properties.

Summary Sand and solids are removed from production separators either off line (shut down for physical removal) or on line by use of jetting systems. Traditional jetting designs use spray nozzles to fluidize and push the sand toward a covered outlet to evacuate the solids from the vessel. Cyclonic-jetting technology combines the fluidization and evacuation functions into a single, compact device. On the basis of a hydrocyclonic platform, this technology converts jetting spray water into shielded vortex flow that fluidizes sand in a circular zone without disturbing the oil/water interface. Total solids removal is primarily a function of set height, spray flow, and spacing. A single unit was optimized at a set height of 10 cm (4 in.) with spray pressure of 0.7 barg (11 psig) to provide an area of influence of 1.1 m2 (12.0 ft2) with 28 cm (11 in.) of sandbed depth. Placing two units in parallel with overlap of their affected zones reduces the ’egg-carton’ effect associated with this technology; however, optimum operation, in terms of total sand removed, occurs when the units do not overlap. Slurry at up to 60 wt% solids is transported from the jetting system to the handling equipment. The boundary design conditions for slurry transport are erosion velocity (upper limit) and particle-transport velocity (lower limit). By use of published models, the piping design for four-unit cluster of cyclonic-jetting devices was validated at 5.0-cm (2-in.) nominal size. Integration and operation of a jetting system with transport, dewatering, and disposal stages of facilities sand management are presented as guidelines for system design.

The Jorf Lasfar phosphate slurry pipeline in Morocco, commissioned in April 2014, is one of the world's largest slurry pipelines. The pipeline receives phosphate ore from the El Halassa, MEA and Daoui wash plants situated up to 22 km away. The product from these plants varies in grade and quality and is stored in separate agitated slurry tanks at the Khouribga head station. From the head station the slurry is pumped 187 km in batches separated by water to the terminal station at Jorf Lasfar. As these batches of phosphate slurry arrive at the terminal station they are diverted to dedicated storage tanks that feed separate process streams in the refinery. This means that the pipeline design needs to accommodate the slurry transport requirements of the different batches and to be able identify where these batches are during transport so as to ensure they are allocated to the appropriate tanks. As the batches are intermittent and have variable flow properties the design needs to accommodate a wide range of operating conditions. This is achieved by controlling the pipeline operation by varying the pumping head and through a series of pressure monitoring stations and a choke station at the terminal. Due to the scale of the project the system comprises some of the largest slurry handling equipment yet produced and this presented many unique challenges for the engineering team that required an innovative approach to solving such unique problems. This paper presents a few of the design and engineering challenges faced by the engineering team responsible for successfully delivering this project.

Although sophisticated 2 and 3 layer models exist for slurry flow (here the flow of sand/gravel water mixtures), the main Dutch and Belgium dredging companies still use modified Durand and Condolios (1952) and Fuhrboter (1961) models, while the main companies in the USA use a modified Wilson et al. (1992) model for heterogeneous transport. These older models use one term for the excess pressure losses, the pressure losses resulting from the solids, with an empirical character. A new model has been developed based on energy considerations. The model consists of two terms for the excess pressure losses, one for the potential energy losses and one for the kinetic energy losses. This gives more flexibility matching experimental results. Although the model is derived fundamentally, the slip velocity of the particles is still an unknown in the model. An equation for this slip velocity is derived, based on physical parameters. The resulting model is validated with numerous experimental data from the literature and from the Delft Dredging Laboratory and matches very well. The advantage of this model is, that it requires the parameters known to the dredging industry and is thus easy to use.

Modern long distance ore pipeline systems are subject to strong costs, both from the economic and environmental standpoints. The task of assessing the relative importance of energy and water consumption without a detailed engineering analysis is often not obvious. In the present paper, the relative importance of water and energy unit costs is assessed by a novel dimensionless formulation accounting for the essential hydraulic and cost elements that conform the slurry transport. It is found that, for conditions resembling those of copper and iron concentrate pipelines, the ratio between energy and water costs has a wide range, depending on the particular transport conditions and unit cost scenarios. Although operating at similar volume fractions, results indicate that energy/water cost relations may differ between copper and iron concentrate pipelines and local conditions, thus suggesting the need to explicitly include energy and water cost in the design strategy.

Subsea minerals exist in the deep water within Japanese exclusive economic zone. Development of slurry pump passing large particles is required for lifting ore. In design of slurry pump, it is significant to estimate the pressure loss in a riser pipe for large particle slurry transport. Therefore the authors have been studied the slurry flow model for large particle slurry transport. In addition, the authors developed the model for the static pipe including the inclined configurations. Since the lifting pipe will be oscillated due to the connected ship motion and VIV (Vortex Induced Vibration), the authors conducted the scaled model experiment to investigate the effects of pipe oscillation on the pressure loss. The model scale was 1/8. Alumina beads and glass beads were used as solid particles in the experiment. The pipe was vertical, and oscillated in horizontal or vertical direction. The experimental results showed that the horizontal and vertical oscillation had little influence on the static pressure loss in most of the experimental conditions. However the influence was observed for the horizontally oscillating pipe in the low slurry velocity and short oscillation period condition. On the other hand, the significant fluctuation components of pressure loss and flow rate were observed in vertically oscillating pipe. The results also indicated that the density of slurry and amplitude of oscillation had influence on the fluctuation components of pressure loss and flow rate but the particle diameters had little influence on them.

The results of a long term abrasion test on 10" hoses were compared to flow simulation based abrasion calculations. An impact angle dependent small scale abrasion test was carried out on the rubber liner material to establish input data for abrasion simulation. The simulation proved to be very sensitive to the dependence of the impact angle on the abrasion rate, particularly at low impact angles. Three different lining materials were applied in the full scale test: rubber, a proprietary plastic liner and rubber with built in hard steel rings using a purpose built machine. The abrasion rate increased in the following order: armored liner, rubber and plastic, although the plastic had better Schopper abrasion than rubber.

The pulp lifter is an integral component of autogenous (AG) and semi-autogenous (SAG) grinding mills as it controls the throughput, performance and efficiency of mills. The slurry transport from the AG/SAG mill through grate holes into the discharge trunnion is the main function of the pulp lifter. This process develops complex flow behaviour in the region of the grate and pulp lifter. Efficient and effective removal of pulp/slurry from the mill is the key objective of the pulp lifter design. This work aims to understand slurry flow behaviour in pulp lifter sections and its contribution to mill performance using computational fluid dynamics (CFD) modelling and Laser Doppler Anemometry (LDA) measurements applied to a laboratory scale mill. The CFD model is validated against the LDA measurements, and then used to build a cohesive computational framework for modelling industrial pulp lifters, to investigate unique problems associated with their design and performance.

The term efficiency in hydraulic transport system design and operation has several possible interpretations. Whether it may stand for energy consumption, it may also aim to the minimization of the water or the carbon footprint. All these tentative means of efficiency should meet project and operational goals, including throughput constraints. The consideration of these aspects altogether, seeking for best project and operational conditions, represents a major optimization problem which, on the other hand, depends on the evolution of input variables for slurry transport along with environmental, energy and water consumption costs. In this paper, an example of a long distance ore pipeline with plant demand-dependent inputs is studied in the light of the implementation of an optimization problem. Results have been compared with those corresponding to typical transport modes, and show that common operational conditions differ from those optimized in terms of system utilization, flow rate and slurry concentration. In particular, the optimal computed parameters include lower fractions of the total available times, lower flow rates and higher concentrations than in typical systems, thus suggesting a different design and operational rationale.

In dredging the main process to transport soil is slurry transport. The most well-known models to predict head losses are the models of Durand and Condolios which were presented in 1952, of Newitt et al. in 1955, Jufin and Lopatin in 1966, Wilson et al. in 1992 and Führböter in 1961. All models describe heterogeneous flow and some, namely those of Newitt et al. and Wilson et al., also apply to a stationary and sliding bed. The heterogeneous models are all empirical, based on the experiments carried out and contain one term for the excess hydraulic gradient losses. In 2013 Miedema and Ramsdell developed a new model based on energy considerations, containing a potential energy term and a kinetic energy term for uniform sands and gravels. An attempt is made to explain the Führböter model more physically based on the model of Miedema and Ramsdell. The use of the so-called Skt factor is rejected based on the arguments presented. A set of equations and curves are derived for the so-called Sk factor of Führböter with mean, lower limit and upper limit curves, enabling the user to adapt the Sk curve depending on the pipe diameter and the liquid viscosity. The new Sk equations are based on physics and match the experiments of Führböter very well.

High-cencentration slurry transport can reduce the water content in bottom sludges and relieve the dehydration pressure in slurry storage areas, therefore accelerating the follow-up dealings with sludges and improving resource utilization. To meet such demand for high-concentration slurry transport, this article makes designs for a set of pipeline transportation testing apparatuses, and offers possible follow-up research with testing evidences such as measurements of pipeline pressure and concentration distribution, as well as monitored slurry flow regimes inside the pipes.

One of the important trends of development of hydromechanization in hydraulic engineering is the transport of solids in the form of slurries. Slurry is a thick suspension of solids in a liquid. Clogging of the pipeline carrying slurry will not occur if the velocity of the slurry is more than some critical value. Critical flow velocity, which is the minimum velocity to maintain all solid particles in a suspension condition, is the important design parameter in slurry transport through pipelines. Gene-expression programming (GEP) and adaptive neuro-fuzzy inference system (ANFIS) models are developed in this study for the estimation of critical velocity. The estimated critical velocity by GEP and ANFIS models are compared with existing empirical equations and it is found that the ANFIS model produces better results compared with GEP and other existing equations.

Solid–fluid multiphase flows are often encountered in chemical engineering operations, such as bead milling, slurry transport, and mixing. Numerical simulation is a promising approach for the design and investigation of operational conditions. In previous studies, an Eulerian–Lagrangian coupling method was developed for solid–liquid flows. However, it is difficult to apply this method to moving boundary problems because of the excessive calculation costs due to adaptive mesh or sliding mesh. To solve the difficulty, a Lagrangian–Lagrangian coupling method has been developed, which couples the Discrete Element Method (DEM) for the solid phase and the Moving Particle Semi-Implicit (MPS) method for the fluid phase. It can successfully calculate solid–fluid flows and has been validated, although it has been applied only to two-dimensional systems. In the present study, we develop a three-dimensional DEM–MPS method and apply it to bead mill systems, and show the effectiveness of the method. The simulation results, namely, the solid particle distribution and velocity are compared with experimental results and we thus demonstrate the validity of the method.

Low-carbon steel with pearlite–ferrite microstructure has been extensively used for oil sands slurry transport. As expected, the carbon concentration strongly affects the performance of the steel, which is largely attributed to the volume fraction ratio of pearlite to ferrite that is governed by the carbon concentration. However, it is often noticed in experiments that even a small change in the carbon concentration could lead to considerable difference in the erosion resistance. Thus, more detailed studies are needed to clarify the mechanism responsible for such observed difference in order to tailor low-carbon steel more effectively. In this study, using a micro-scale dynamic model (MSDM) we conducted computational modeling to investigate effects of the volume fraction ratio of pearlite to ferrite and the orientation of lamellar cementite on the erosion resistance of low-carbon steel in order to better understand the effect of microstructure features on the performance of the steel. It was demonstrated that the performance of horizontally aligned cementite plates (i.e. parallel to sample surface) was inferior to that of vertically aligned ones. Higher fraction ratios of pearlite to ferrite resulted in increased erosion resistance. Possible mechanisms responsible for the observed phenomena were analyzed and discussed.

Laser and plasma transferred arc (PTA) deposition processes are highly flexible in that a wide range of metal alloys can be melted in these processes to deposit thin layers (0.5-3.0mm) over a cheaper substrate, thus making these processes attractive and economically viable for the mineral processing industry. Surface erosion by abrasive slurry motion is a common problem in mineral processing equipment. The predominant factors which contribute to the surface erosion include particle impact velocity and angle, particle properties and sizes, and properties of material surface on which erosion occurs. However, for given operating conditions and processes the rate of erosion mainly depends on surface properties of components, i.e. the substrates.This study explores the possibility of using high power industrial laser and PTA in the deposition of overlays to produce improved erosion resistant layers over the substrates. These two processes were used to deposit cobalt and nickel base alloy layers on mild steel substrate which were subjected to laboratory scale slurry erosion test. The test results revealed that nickel based alloys performed better than cobalt base alloys. These results were also found to be comparable with that of white iron alloys.Laser and plasma transferred arc (PTA) deposition processes are highly flexible in that a wide range of metal alloys can be melted in these processes to deposit thin layers (0.5-3.0mm) over a cheaper substrate, thus making these processes attractive and economically viable for the mineral processing industry. Surface erosion by abrasive slurry motion is a common problem in mineral processing equipment. The predominant factors which contribute to the surface erosion include particle impact velocity and angle, particle properties and sizes, and properties of material surface on which erosion occurs. However, for given operating conditions and processes the rate of erosion mainly depends on surface properties of components, i.e. the substrates.This study explores the possibility of using high power industrial laser and PTA in the deposition of overlays to produce improved erosion resistant layers over the substrates. These two processes were used to deposit cobalt and nickel base alloy layers on mild steel s...

Solid–liquid flows involving a free surface are widely encountered in chemical engineering, such as wet ball milling, slurry transport and mixing. Numerical simulation is useful both for the design and investigation of operational conditions in the industrial processes. However, numerical approaches for modeling solid–liquid flows were not yet established. This is because the modeling of the free surface and solid phase has been difficult and because the calculation cost may become huge. To solve the difficulties, we have developed a new method for numerical modeling of solid–liquid flows involving a free surface. In this study, we present the DEM–MPS method, in which solid–liquid flows are computed by combining the discrete element method (DEM) with the moving particle semi-implicit (MPS) method. Besides, new wall boundary modeling was proposed to perform the simulations of the solid–liquid flows in practical systems by the DEM–MPS method. The DEM–MPS method was validated against a solid–liquid flow in a rotating tank.

Although multi-sized particles slurries are transported in practical pipelines, most reported correlations were proposed for single-size slurries. If the average diameter of solids is used to estimate the drag coefficient of multi-sized particles slurries, the hydraulic gradients with these correlations lead to considerable scatter of data . Kazanskij , Moro , and STSJ (Slurry Transport Society of Japan) [4] summarised some empirical equations of hydraulic gradient of slurry flow with experimental data. The Wasp method [5] recommended by Liu [6] has been used by designers of pipeline systems for predicting hydraulic gradient of compound slurries of homogeneous and heterogeneous flows. However, the method is limited for application to a wide range of transport conditions. Kaushal et al. [7] also discussed the limitations and attempted to modify the method. They concluded that the Wasp method provided reasonable accurate results at limited low concentrations. The purpose of this paper is to discuss the limitations of application of other researchers' correlations and to develop innovated models, based on the single-size slurry model of Seitshiro et al. [8] The analytical models depend on particle size distribution: (1) coarse-coarse model; for a slurry consisting of two fine particles in high concentration. The fine solids are defined as particles with sizes smaller than the critical diameter [9] in this study. For both models, it is assumed that the coarse solids in the slurry do not hinder each other's movements. Experiments were performed in a 1-inch transparent pipe with sand-bakelite mixed slurries. The data of Shook et al. , Boothroyde et al. , and that of this study were used to verify the application of the models. The analytical results suggest that the innovated models can be effective for designing slurry pipelines.

The evolution of the configuration of a set of particles dispersed in a flowing liquid is crucial in many applications such as sedimentation, slurry transport, rheology and structured arrays of micro- and nano-particles. Direct simulation based on what is called fictitious domain method coupled with finite element method has been used to study particulate flows and sedimentation process. Here we extend the previously proposed formulations to naturally include buoyancy force and the capillary driven attraction or repulsion of particles located at fluid interfaces. The set of differential equations is discretized using a fully implicit-fully coupled fictitious domain/finite element approach, avoiding numerical instabilities that may arise from explicit integration. The proposed formulation and implementation are validated by comparing the predictions of simple 2D flows to available numerical or analytical solutions. The method is then used to analyze the flotation of 2D particles and capillary driven aggregation at fluid interfaces.

A clear understanding of pipeline dredge production capacity provides dredge operators and dredging project planners with the capability to accurately and effectively determine a project’s cost and duration. Dredge pump and pipeline hydraulics coupled with slurry transport principles present a complex and challenging engineering system requiring specialized knowledge and understanding of how the system will operate. This study determines how well the theoretical principles of hydraulics and slurry transport govern the actual pipeline dredging process, compared with dredge pump and pipeline instrumentation data. Results indicate that the delivered pipeline slurry mixture incurred more friction losses during transport than water alone. This study further determines the maximum pumping capability of the dredge pump in terms of its maximum dredging depth and maximum pipeline length. These results determine that the pipeline dredge operated well within its operating limits during the case study. Overall, the c...

Slurry suspension in holding tanks and transport through pipelines are essential elements in the modern mining and mineral processing industry. This paper presents methods to improve the energy efficiency of solids suspension in tanks and slurry transport through pipelines for low viscosity Newtonian slurries. Research has been conducted using laboratory experiments and analysis using established equations. It is shown that there are many similarities between these two traditionally separated research areas. It is concluded that energy per unit solids mass generally varies with solids concentration for both systems. The specific energy can be minimised by operating at a suitable solids concentration, for example in the range of 20-30% (v/v) for the slurry properties considered in this paper. It is also concluded that the specific energy generally decreases with the size of equipment, i.e. tank diameter or pipe diameter, although this effect tends to plateau at large sizes. It was found that when a slurry pipeline is used as a reactor, it generally requires more power to suspend solids per unit solids mass than a mixing tank. Great energy saving can be achieved by operating a slurry tank with baffles removed, if off-bottom solids suspension is the limiting factor. Basic equations for specific energy consumption (SEC) are included.

Four distinct regimes were found existent (namely sliding bed, saltation, heterogeneous suspension and homogeneous suspension) in slurry flow in pipeline depending upon the average velocity of flow. In the literature, few numbers of correlations has been proposed for identification of these regimes in slurry pipelines. Regime identification is important for slurry pipeline design as they are the prerequisite to apply different pressure drop correlation in different regime. However, available correlations fail to predict the regime over a wide range of conditions. Based on a databank of around 800 measurements collected from the open literature, a method has been proposed to identify the regime using artificial neural network (ANN) modeling. The method incorporates hybrid artificial neural network and differential evolution technique (ANN - DE) for efficient tuning of ANN Meta parameters. Statistical analysis showed that the proposed method has an average misclassification error of 0.03%. A comparison with selected correlations in the literature showed that the developed ANN - DE method noticeably improved prediction of regime over a wide range of operating conditions, physical properties, and pipe diameters. .

Four distinct regimes (namely sliding bed, saltation, heterogeneous suspension, and homogeneous suspension) were found existent in slurry flow in a pipeline depending upon the average velocity of flow. In the literature, a few numbers of correlations have been proposed for identification of these regimes in slurry pipelines.Regime identification is important for slurry pipeline design as it is the prerequisite to apply different pressure drop correlations in different regimes. However, available correlations fail to predict the regime over a wide range of conditions. Based on a databank of around 800 measurements collected from the open literature, a method has been proposed to identify the regime using support vector machine (SVM) modeling. The method incorporates hybrid support vector machine and genetic algorithm technique (SVM-GA) for efficient tuning of SVM meta-parameters. Statistical analysis showed that the proposed method has an average misclassification error (AARE) of 0.03%. A comparison with selected correlations in the literature showed that the developed SVM-GA method noticeably improved prediction of regimes over a wide range of operating conditions, physical properties, and pipe diameters. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

For subsea mining, the estimation of pressure loss in the pipe of lifting system and the flexible pipe to connect the mining tool and the lifting system is important to design the mining system. The configuration of flexible pipe is expected to have an inclined part. In the present paper, the authors carried out the experiment to measure the pressure loss in inclined pipes using alumina beads to investigate the effect of inclination angle of pipe on the pressure loss. Furthermore, a mathematical model to estimate the pressure loss in inclined pipes was proposed and validated through the experiments. As the result of the validation, it was confirmed that the proposed model could be applied to the pressure loss estimation in inclined pipes.

DEM modelling of the motion of coarse fractions of the charge inside SAG mills has now been well established for more than a decade. In these models the effect of slurry has broadly been ignored due to its complexity. Smoothed particle hydrodynamics (SPH) provides a particle based method for modelling complex free surface fluid flows and is well suited to modelling fluid flow in mills. Previous modelling has demonstrated the powerful ability of SPH to capture dynamic fluid flow effects such as lifters crashing into slurry pools, fluid draining from lifters, flow through grates and pulp lifter discharge. However, all these examples were limited by the ability to model only the slurry in the mill without the charge. In this paper, we represent the charge as a dynamic porous media through which the SPH fluid is then able to flow. The porous media properties (specifically the spatial distribution of porosity and velocity) are predicted by time averaging the mill charge predicted using a large scale DEM model. This allows prediction of transient and steady state slurry distributions in the mill and allows its variation with operating parameters, slurry viscosity and slurry volume, to be explored.

We describe a modelling approach to slurry transport in dynamic beds. Volume and time averaging are combined to obtain a dynamic replacement for the static Ergun equation. Solutions of the resulting dynamic equation are exhibited for a simple charge-motion model, which serves as the prototype for a practical slurry transport model.

Pulp lifters, also known, as pan lifters are an integral part of the majority of autogenous (AG), semi-autogenous (SAG) and grate discharge ball mills. The performance of the pulp lifters in conjunction with grate design determines the ultimate flow capacity of these mills. Although the function of the pulp lifters is simply to transport the slurry passed through the discharge grate into the discharge trunnion, their performance depends on their design as well as that of the grate and operating conditions such as mill speed and charge level. However, little or no work has been reported on the performance of grate-pulp lifter assemblies and in particular the influence of pulp lifter design on slurry transport. Ideally, the discharge rate through a grate-pulp lifter assembly should be equal to the discharge rate through at a given mill hold-up. However, the results obtained have shown that conventional pulp lifter designs cause considerable restrictions to flow resulting in reduced flow capacity. In this second of a two-part series of papers the performance of conventional pulp lifters (radial and spiral designs) is described and is based on extensive test work carried out in a I m diameter pilot SAG mill. (C) 2003 Elsevier Science Ltd. All rights reserved.

In Deep Sea Mining, material will be excavated at the sea floor and transported to the surface. This transport always consists of horizontal and vertical transport and can be carried out mechanically or hydraulically. If the transport is hydraulically, during the horizontal transport there is a danger of bed formation and plugging the line. This is similar to the horizontal transport in dredging with the difference that in deep-sea mining the line length is much smaller, but also the line speeds may be smaller. To avoid plugging the line, the line speed has to be higher than a certain critical line speed. In literature there are many theories about this critical line speed and about bed forming in the pipe, but these theories are usually empirical and cannot be applied under all circumstances. Different particles sizes, pipe diameters and line speeds require different equations, although a generic theory should cover everything. For the critical velocity different definitions exist. Some researchers use the definition that above the critical velocity no bed, either stationary or sliding, exits. This definition is also referred to as the limit deposit velocity. Others use the transition between a stationary bed and a sliding bed as the definition of the critical velocity. Whatever definition is used, the Moody friction factor on the bed always plays an important role. Since in literature no explicit formulation for this Moody friction factor exists, an attempt is made to find an explicit formulation for the Moody friction factor for the interface of the fluid flow and the bed, where this interface consists of sheet flow.Copyright © 2014 by ASME

In the capsule hoist system, cylindrical capsules, loaded with minerals, are inserted into the lower end of a vertical water-filled shaft. The capsules having low mass density are lifted due to natural buoyant forces. These capsules are taken out at the upper end of the shaft. The attractive feature of the system is that it only requires power for inserting the capsules. Compared with slurry transport no mechanism is required to separate the transported mineral from water, and it does not require a continuous supply of water. Although some research work has appeared in this area, the design equations have not been attempted as yet. In this paper the design of a capsule transporting hoist system has been formulated as a constrained geometric programming problem having zero degree of difficulty. The solution of the problem yielded the design variables in the form of explicit equations.

Pipeline transport of solids containerized in capsules has several attractive features. As compared to slurry transport the cargo is not wetted or contaminated by the carrier fluid; no mechanism is required to separate the transported material from the fluid other than the use of capsules; and foremost, it requires less power for maintaining the flow. Although considerable research work has appeared in the last three decades, design equations have not been attempted as yet. In this paper the design of a capsule transporting pipeline has been formulated as a geometric programming problem. The solution of the problem yielded the design variables in the form of explicit equations.

In order to provide a technical basis for preventing the blockage of heterogeneous slurry pipelines, the unsteady characteristics of slurry transport were studied. Our experiments were carried out using a test pipeline of about 130m long and 50mm in diameter. The flow rate, the solid concentration and the pressures were measured in the pipeline, in terms of responses to a stepwise charge of solid particles. It became clear how behavior of slurry changed in the pipeline if it changed with the feed rate of solid particles and how the phenomenon of the pipe blockage happened. Various information and data were obtained from these experiments, which will be useful in planning and in operating heterogeneous slurry pipelines.

The Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) sponsored a workshop on non-Newtonian multiphase slurry at NETL’s Morgantown campus August 19 and 20, 2013. The objective of this special two-day meeting of 20-30 invited experts from industry, National Labs and academia was to identify and address technical issues associated with handling non-Newtonian multiphase slurries across various facilities managed by DOE. Particular emphasis during this workshop was placed on applications managed by the Office of Environmental Management (EM). The workshop was preceded by two webinars wherein personnel from ORP and NETL provided background information on the Hanford WTP project and discussed the critical design challenges facing this project. In non-Newtonian fluids, viscosity is not constant and exhibits a complex dependence on applied shear stress or deformation. Many applications under EM’s tank farm mission involve non-Newtonian slurries that are multiphase in nature; tank farm storage and handling, slurry transport, and mixing all involve multiphase flow dynamics, which require an improved understanding of the mechanisms responsible for rheological changes in non-Newtonian multiphase slurries (NNMS). To discuss the issues in predicting the behavior of NNMS, the workshop focused on two topic areas: (1) State-of-the-art in non-Newtonian Multiphase Slurry Flow, and (2) Scalingmore » up with Confidence and Ensuring Safe and Reliable Long-Term Operation.« less

Recent developments in subsea mining as well as oil & gas exploration and development drilling will require the use of a subsea pumping solution capable of handling slurries. These slurries are characterized by relatively large particle sizes and non-uniform flow conditions including fluctuating solids concentrations, densities, viscosities, and maximum particle size in both the mining and drilling applications. While challenging enough in surface applications, slurry transport problems are exacerbated by the vertical lift required in subsea use. This paper will first present the effect of each varying parameter on the overall horsepower required. Additionally, the pumping efficiency of some different pump types when responding to these changing conditions will be shown. From a control perspective, altering a pump’s speed in response to changing flow conditions presents some unique challenges. As an alternative to adjusting a rotary pump’s speed, an algorithm to control a positive displacement pumping solution to automatically adjust its output in this application is presented.Copyright © 2010 by ASME

Experience in the area of wet mining and the dredging industry learns that the excavation system cannot be seen separate from the slurry transportation system. These two key systems in a deep sea mining operation interrelate to such extend that they must be developed towards an integral solution. The nominal production, peak production and variability of these figures must match for all sub-systems in the overall mining system to optimize for mining efficiency; we call this the ‘game of capacities’. Also the configuration of the excavation and transport system has great consequences. For instance an important question is whether to place the first pump and its drive of the slurry transport system on the seafloor mining tool or in the riser system. The choices made impact amongst others on; the mining tool’s reach (and thus efficiency), the seafloor mining tool’s propulsion system and its geo-mechanical interaction, the slurry transport flow and pumping power requirements. This paper will discuss the several dependencies of the (producing) subsystems and important choices for configuration and their consequences regarding technology, capex, opex, reliability and maintainability.Copyright © 2010 by ASME

Four distinct regimes were found existent (namely sliding bed, saltation, heterogeneous suspension and homogeneous suspension) in slurry flow in pipeline depending upon the average velocity of flow. In the literature, few numbers of correlations has been proposed for identification of these regimes in slurry pipelines. Regime identification is important for slurry pipeline design as they are the prerequisite to apply different pressure drop correlation in different regime. However, available correlations fail to predict the regime over a wide range of conditions. Based on a databank of around 800 measurements collected from the open literature, a method has been proposed to identify the regime using artificial neural network (ANN) modeling. The method incorporates hybrid artificial neural network and genetic algorithm technique (ANN-GA) for efficient tuning of ANN meta parameters. Statistical analysis showed that the proposed method has an average misclassification error of 0.03%. A comparison with selected correlations in the literature showed that the developed ANN-GA method noticeably improved prediction of regime over a wide range of operating conditions, physical properties, and pipe diameters.

The WTP pipe plugging issue, as stated by the External Flowsheet Review Team (EFRT) Executive Summary, is as follows: “Piping that transports slurries will plug unless it is properly designed to minimize this risk. This design approach has not been followed consistently, which will lead to frequent shutdowns due to line plugging.” A strategy was employed to perform critical-velocity tests on several physical simulants. Critical velocity is defined as the point where a stationary bed of particles deposits on the bottom of a straight horizontal pipe during slurry transport operations. Results from the critical velocity testing provide an indication of slurry stability as a function of fluid rheological properties and transport conditions. The experimental results are compared to the WTP design guide on slurry transport velocity in an effort to confirm minimum waste velocity and flushing velocity requirements as established by calculations and critical line velocity correlations in the design guide. The major findings of this testing is discussed below. Experimental results indicate that the use of the Oroskar and Turian (1980) correlation in the design guide is conservative—Slurry viscosity has a greater affect on particles with a large surface area to mass ratio. The increased viscous forces on these particles result in a decrease in predicted critical velocities from this traditional industry derived equations that focus on particles large than 100 m in size. Since the Hanford slurry particles generally have large surface area to mass ratios, the reliance on such equations in the Hall (2006) design guide is conservative. Additionally, the use of the 95% percentile particle size as an input to this equation is conservative. However, test results indicate that the use of an average particle density as an input to the equation is not conservative. Particle density has a large influence on the overall result returned by the correlation. Lastly, the viscosity correlation used in the WTP design guide has been shown to be inaccurate for Hanford waste feed materials. The use of the Thomas (1979) correlation in the design guide is not conservative—In cases where 100% of the particles are smaller than 74 m or particles are considered to be homogeneous due to yield stress forces suspending the particles the homogeneous fraction of the slurry can be set to 100%. In such cases, the predicted critical velocity based on the conservative Oroskar and Turian (1980) correlation is reduced to zero and the design guide returns a value from the Thomas (1979) correlation. The measured data in this report show that the Thomas (1979) correlation predictions often fall below that measured experimental values. A non-Newtonian deposition velocity design guide should be developed for the WTP— Since the WTP design guide is limited to Newtonian fluids and the WTP expects to process large quantities of such materials, the existing design guide should be modified address such systems. A central experimental finding of this testing is that the flow velocity required to reach turbulent flow increases with slurry rheological properties due to viscous forces dampening the formation of turbulent eddies. The flow becomes dominated by viscous forces rather than turbulent eddies. Since the turbulent eddies necessary for particle transport are not present, the particles will settle when crossing this boundary called the transitional deposition boundary. This deposition mechanism should be expected and designed for in the WTP.

Accurate estimates of the hauling capacity of spreader tank systems are needed to create valid models which give meaningful comparisons between system alternatives. In the last several years livestock farms in the Great Lakes Region have expanded and increased in size. With more livestock comes more manure handling and a greater transport distance to reach the land base needed for land application. Because hauling and spreading large volumes of manure can greatly impact peak labor demand and the timeliness of tillage and planting, many farm managers are using custom hire of manure hauling and land application. A time-and-motion study of thirteen liquid manure hauling systems on ten farms using custom hauling services in Michigan, Ohio and Ontario, Canada was done in 2006-2008. Representative time and material flow rates were used to model the hauling capacity of tank spreader systems as a function of spreader tank volume and transport distance. Simulated hauling rates were fit to a general model to develop machinery system-specific coefficients to predict an effective hauling capacity of tractor-drawn and truck-drawn spreader tanks, and hauling systems using truck-drawn nurse tanks for over-the-road transport to tractor-drawn spreader tanks for field spreading. Compared to standard tractor-drawn tank spreaders, spreaders drawn with high-speed tractors and truck-drawn or truck mounted spreaders had an advantage with longer hauls. Compared to injection with a 6-shank injector a broadcast application with a 7000 tractor-drawn spreader (high-speed tractor) increased the hauling rate 25% near storage and 17% with a 2 mile haul. The hauling rate of tank spreader systems was most sensitive to an increase in tank volume and travel speed. A 20% increase in tank volume increased the effective hauling rate about 8% with a 0.1 mile haul and more than 16% with a 10 mile haul. A 20% increase in travel speed had little effect when hauling near storage, but increased the hauling rate more than 7% with a 2 mile haul, and more than 14% with a 10 mile haul.

Mining operations are major producers of greenhouse gases and energy consumers. Norgate and Haque (2010, 2012) make a strong point regarding the impact and the potential for reductions in energy consumption and greenhouse gas emissions in the mining industry. For the copper concentrate production, they have distinguished different sub-processes, including drilling, basting, loading & hauling, ventilation, dewatering, crushing & grinding, and concentration. They conclude that the loading & hauling stage is the mostenergy-intensive, and that the crushing & grinding stage has the highest potential for energy saving. Although notexactly featuring at the core of the production processes, ore concentrate transport might be an energy-intensive activity when sufficiently long slurry transport lines are installed. In several South American countries, including Chile, Brazil, Peru and Argentina, it is very common for ore concentrate plants to deliver copper, iron or bauxite concentrate through complex topographies connecting distances above 100 km (Jacobs, 1991; Derammelaere and Shou, 2002; Abulnaga, 2002; Santos et al., 2009). Taking into account inventory bases from USA, Australia and Canada, Table 3 in Norgate and Haque (2010) shows, for copper concentrate, an energy consumption of 140 MJ/t at the concentrating stage and 673 MJ/t for dewatering. When applicable, the aforementioned transport process fits between both. Recently, Ihle and Tamburrino (2012) identified specific energy consumptions due to slurry transport in the order of 0.5 MJ/(t km) for a 6 inch nominal diameter pipeline for a dry throughput of 36.7 kg/ s, or about 1.1 million tons per year with a 95% utilization rate. A similar result was obtained by Wu et al. (2010) using a 158 mm internal diameter loop in a laboratory facility. This gives an energy requirement in the order of 50 MJ/t per 100 km pipeline, which can actually reach about twice the value for many long distance concentrate pipeline operations, thus competing with other energy consumption items referred to in Norgate and Haque (2010). Here, there is also significant room for energy efficient design and operation (Ihle and Tamburrino, 2012), and embodied energy and greenhouse gas emissions need to be accounted for and optimized as well. In the particular case of the hydraulic transport of concentrates, it is also necessary to consider the relation between water requirements and energy consumption: less of a water implies less water footprint but, on the other hand, higher energy consumptions, greenhouse gas emissions and embodied energy associated with the final product, the concentrate. A question being pursued in research currently being undertaken by the author is what is the optimal balance between the different elements that minimize the overall environmental impact of new infrastructure and process.

The US Department of Energy Environmental and Waste Management Tanks Focus Area selected as a strategic initiative the need to identify and develop technologies for remediation of tanks that are known or are suspected to leak. This investigation identified and evaluated technical options for single-shell tank waste retrieval applicable to retrieve waste from potentially leaking tanks. Technologies that minimize leakage use minimal water, and dry retrieval technologies were evaluated. Safety, cost, authorization basis, and schedule risks were identified for each technology to provide River Protection Program with information to evaluate technical and programmatic risk. A workshop was held to identify technology needs and solutions. These approaches grouped into five categories: those related to waste dislodging, waste conveyance, both waste dislodging and conveyance, the deployment platform, and technologies related to leak detection, monitoring, and mitigation. Based on the ranking, six technologies were selected as potential candidates for further evaluation. These items were prioritized into four technologies to recommend for further evaluation 1) Air assisted TORE(R). The TORE(R) produces a precessing vortex core with the ability to convey solids at pre-determined slurry concentrations over great distances. The dry TORE(R) concept uses air to develop the vortex to fluidize dry solids. The TORE(R)themore » solids in a slurry transport line. 2) Sonication for waste dislodging utilizes ultrasonic energy to fracture and dislodge hard waste types such as salt cake and sludge. 3) Novel long-reach manipulators concept is to investigate novel cost effective approaches for long-reach manipulator technology. 4) Next generation crawler technology envisions a non-umbilical dislodger, possibly radio controlled and powered remotely to provide a deployment platform not affected by path, or the need to retrace steps.« less

Mobilization of sludge waste stored in underground storage tanks can be achieved safely and reliably by sluicing. In the project discussed in this report, the waste in Hanford single-shell Tank 241-C-106 will be mobilized by sluicing, retrieved by a slurry retrieval pump, and transferred via an 1800-ft slurry pipeline to Tank 241-AY-102. A sluicing strategy must be developed that ensures efficient use of the deployed configuration of the sluicing system: the nozzle(s) and the retrieval pump(s). Given a sluicing system configuration in a particular tank, it is desirable to prescribe the sequential locations at which the sludge will be mobilized and retrieved and the rate at which these mobilization and retrieval processes take place. In addition, it is necessary to know whether the retrieved waste slurry meets the requirements for cross-site slurry transport. Some of the physical phenomena that take place during mobilization and retrieval and certain aspects of the sluicing process are described in this report. First, a mathematical model gives (1) an idealized geometrical representation of where, within the confines of a storage tank containing a certain amount of settled waste, sludge can be removed and mobilized; and (2) a quantitative measure of the amount of sludge that can be removed during a sluicing campaign. A model describing an idealized water jet issuing from a circular nozzle located at a given height above a flat surface is also presented in this report. This dynamic water-jet model provides the basis for improving the geometrical sluicing model presented next. In this model the authors assume that the water jet follows a straight trajectory toward a target point on a flat surface. However, the water jet does not follow a straight line in the actual tank, and using the true trajectory will allow a more accurate estimate of the amount of disturbed material. Also, the authors hope that developing accurate force and pressure fields will lead to a better description of the scouring process and more realistic material removal rates.

The main objective of this project was to conduct intensive research and development of the Coal Log Pipeline (CLP). Specifically, the R & D was to concentrate on previously neglected and insufficiently studied aspects of CLP which were deemed significant. With improvements in these areas, CLP could be implemented for commercial use within five years. CLP technology is capable of transporting coal logs for long distances. The many potential advantages of CLP over truck and railroad transportation include: lower freight costs, less energy consumption, less air pollution, decreased environmental problems, increased safety, and improved reliability. Previous studies have shown that CLP is advantageous over slurry pipeline technology. First, CLP uses one-third the water required by a coal slurry pipeline. Second, CLP provides easier coal dewatering. Third, the CLP conveying capacity of coal is twice as much as a slurry transport line of equal diameter. In many situations, the cost for transporting each ton of coal is expected to be less expensive by CLP as compared to other competing modes of transportation such as: truck, unit train and slurry pipeline.

Wastes stored in Hanford Tank 241-SY-102 are planned to be retrieved from that tank and transferred to 200 East Area through the new pipeline Replacement Cross Site Transfer System (RCSTS). Because the planned transfer of this waste will use the RCSTS, the slurry that results from the mobilization and retrieval operations must meet the applicable waste acceptance criteria for this system. This report describes results of the second phase (the detailed assessment) of the SY-102 waste retrieval study, which is a part of the efforts to establish a technical basis for mobilization of the slurry, waste retrieval, and slurry transport. Hanford Tank 241-SY-102 is located in the SY Tank Farm in the Hanford Site`s 200 West Area. It was built in 1977 to serve as a feed tank for 242-S Evaporator/Crystallizer, receiving supernatant liquid from S, SX, T, and U tank farms. Since 1981, the primary sources of waste have been from 200 West Area facilities, e.g., T-Plant decontamination operations, Plutonium Finishing Plant operations, and the 222-S Laboratory. It is the only active-service double-shell tank (DST) in the 200 West Area and is used as the staging tank for cross-site transfers to 200 East Area DSTs. The tank currently stores approximately 470 kL (125 kgal) of sludge wastes from a variety of sources including the Plutonium Finishing Plant, T-Plant, and the 222-S Laboratory. In addition to the sludge, approximately twice this amount (about 930 kL) of dilute, noncomplexed waste forms a supernatant liquid layer above the sludge.

This activity supports the retrieval data quality objective (DQO) process by identifying the material properties that are important to the design, development, and operation of retrieval equipment; the activity also provides justification for characterizing those properties. These properties, which control tank waste behavior during retrieval operations, are also critical to the development of valid physical simulants for designing retrieval equipment. The waste is to be retrieved in a series of four steps. First, a selected retrieval technology breaks up or dislodges the waste into subsequently smaller pieces. Then, the dislodged waste is conveyed out of the tank through the conveyance line. Next, the waste flows into a separator unit that separates the gaseous phase from the liquid and solid phases. Finally, a unit may be present to condition the slurried waste before transporting it to the treatment facility. This document describes the characterization needs for the proposed processes to accomplish waste retrieval. Baseline mobilization technologies include mixer pump technology, sluicing, and high-pressure water-jet cutting. Other processes that are discussed in this document include slurry formation, pneumatic conveyance, and slurry transport. Section 2.0 gives a background of the DQO process and the different retrieval technologies. Section 3.0 provides the mechanistic descriptionsmore » and material properties critical to the different technologies and processes. Supplemental information on specific technologies and processes is provided in the appendices. Appendix A contains a preliminary sluicing model, and Appendices B and C cover pneumatic transport and slurry transport, respectively, as prepared for this document. Appendix D contains sample calculations for various equations.« less

REVIEW “SLURRY TRANSPORT USING CENTRIFUGAL PUMPS” Elsevier Science Publishers Ltd., Crown House, Linton Rd., Barking, Essex, IG11 8JU U.K., 1992, 355 pp. ISBN 1-85166-745-8 HB £ 52

In slurry transport, the critical velocity is defined as the minimum velocity demarcating flows in which the solids form a bed at the bottom of the pipe (bed load flows) from fully suspended flow. An analysis based on balancing the energy required to suspend the particles with that derived from dissipation of an appropriate fraction of the turbulent eddies is used to develop a correlation for prediction of the critical velocity. Comparison of the results with available experimental critical velocity data, relating to a rather wide variety of slurry systems, confirms that the present correlation does a superior job of prediction than all previously proposed critical velocity correlations.