One strategy to manage pig slurry is centrifugation and composting of the solids fraction to produce a value added product to distribute manure nutrients further from productions sites. This study determined turned windrow composting was suitable for processing slurry solids throughout winter. It was also the first attempt at combining automated chambers and a Fourier Transform Infrared spectroscopy analyzer to measure multiple gases during the composting process; the system proved capable but captured fluxes better if conducted in an area sheltered from wind. Straw and woodshavings were shown suitable as bulking materials for composting slurry solids, however, the lack of porosity provided by woodshavings created anaerobic conditions that doubled the greenhouse gas emissions compared to those of straw, 1,126 kg CO2-equivalent Mg-1 compared to 526 kg CO2-equivalent Mg-1. Either bulking material produced compost of quality for use in agricultural or soil blending applications and was free of manure pathogens. / May 2016

Master of Science in Engineering - Engineering / The most significant benefit of co-disposal of tailings based on the “Paste and Thickened Tailings Disposal” concept is the improved ability to “design” the properties of the co-disposed tailings material to suit the surrounding environment. The overall aim of this study was to gain a better understanding of the relationship between the key slurry material characteristics and the flow behaviour of co-disposed tailings upon deposition, for the case of montmorillonite clay-based kimberlite tailings. A fundamental understanding of this relationship will enable the successful manipulation and exploitation of the co-disposed tailings rheology for optimal tailings disposal and the minimisation of associated financial, environmental and social risks. The key material characteristics selected for investigation were the vehicle solids concentration, suspension pH and vehicle to load ratio. The yield stress was selected as the key rheological property representing both the vehicle component rheology and co-disposed tailings rheology. Two yield stress measurement techniques were used, namely (1) direct yield stress measurement with the vane method and (2) indirect yield stress measurement with the slump test method. The correlation between these two methods was investigated as a secondary objective of this study. It was concluded that the suspension pH strongly influences the degree of microscopic particle interaction of the vehicle component and that manipulation of the suspension pH could move the material between interactive and noninteractive states. It was further concluded that increasing load mass percentage leads to a significant increase in the co-disposed material yield stress. It is believed that the load component mainly affects the co-disposed material yield stress through its contribution to the total solids concentration, which in turn results in an exponential increase in the material yield stress. The findings of this study showed remarkable flexibility in the manipulation of the various input parameters to produce the same yield stress value. It is therefore now possible to maintain a constant yield stress value as required by the environmental depositional requirements through various combinations of the input parameters and so keep the integrity of the deposition site intact. The correlation obtained in this study between the vane and slump test yield stress measurement techniques was fairly poor. The slump test only provided an accurate prediction of the yield stress when the material was in a highly interactive state. It is recommended that future research focuses on the thixotropic nature of the vehicle component as a function of suspension pH, the accuracy of the correlation between the vane and slump measured yield stress and the effect of the load on the bulk rheology of the co-disposed material.

In South Africa mineral processing is a very important activity and ""lith declining om grades and increased need for foreign' revenue it is necessarv to develop methods which wUl keep are processing'~osts as low as possible. (( Milling is an example of a capital intensive unit operation 'which has much scope for more efficient Operation. Better control of the viscosity of the slurry discharged from a rotary 9rir~ding mill will result in improved milling efficiency and hence a saving 1'1electricity ~nd steel costs will be experienced. More effective and conslstent grinding in the mil! will also result in em lmproved mineral recovery. Slurry rheology is the variable of interest in monitoring and controlling a wet grinding mill rather than other rneascres of slurry composition presently used (eg percent solids). Up to this point in time however this variable has not been successfully used due to the fact that a sufficiently reliable and robust device for measuring the viscosities of slurries on an on-line basis has riot been available, This project was undertaken to develop just such a device (which is in the process of being patented bV Professor M H Mays). The flow rate of a fluid down a vertical tube is a function if its viscosity as well as ether quantifiable variables. This is the basis of the operation of the measurement device. Useful features of this device Include the fact tl'tat it has no movin~ paris, is inexpensive and robust and is subject tli) little wear. ''rha measurement can b --------------------------------------.--~~-----~------ performed directly on the stream in question and it is unlikely to be blocked up by fibres/particles. A self cleaning facility may also be Included. Ba$ed On the experimental results the technique shows much promise and it is anticipate:ted that the basic design could easily evolve into a useful, practical devi~e for th~ measurement of the apparent viscosity of settling slurries as well as other fluids. If a differential pressure tell" Is also connected to the device it may be used to obtain the density of the fluid being sampled. A model based on the. principles of conservation of momentum was developed and solved numerically using MATLAB {which uses 5th order Runge Kuttal as well as a Turbo pascal program using 4th order Runge i<utta. The model was also' simp.lified slightly by neglecting acceleration of th~ flui¢ (a simplificatlcbn which was shown ~xperimentally to hold) and solved analytically. The results predict~d by the model ~3~ffar only slightly from the experimentally determined i' results. The devil~e has been tested on pilot mills at MINTEK's research facility as wall as the Anglo American Research labs, with varying degrees of success.

Concentrated kaolin clay slurries are found in a number of industrial operations including mine tailings surface disposal, underground paste backfill, and riverbed dredging. An understanding of the impact of solids concentration and addition of chemical species on slurry rheology is of importance to designers of pipeline transport and waste disposal systems. A project to determine the rheology of an idealized industrial kaolin clay slurry using a concentric cylinder viscometer and an experimental pipeline loop was undertaken. Additional laboratory test work including particle size analysis, slurry pH, calcium ion concentration in the slurry supernatant and particle electrophoretic mobility measurements were completed to aid in the understanding of their effects on the slurry rheology. The slurries were prepared in varying kaolin clay solids concentrations with reverse osmosis water. A flocculant, dihydrated calcium chloride (CaCl2 ¡¤ 2H2O), was added to the reverse osmosis water in concentrations equivalent to those found in typical industrial hard water supply. A dispersant, tetra-sodium pyrophosphate (TSPP, Na4P2O7) was used to disperse the clay particles for selected slurries. It was found that the kaolin clay slurries, in the absence of TSPP, exhibited yield stresses and could be characterized with either the two-parameter Bingham or Casson continuum flow models. Increasing the clay concentration in the slurry, while keeping the mass ratio of flocculant to kaolin constant, increased both the yield and plastic viscosity parameters. There was generally good agreement between the rheological parameters obtained in the Couette flow viscometer and that in the pipeline loop. In slurries for which it was possible to obtain turbulent flow, the transition to turbulent flow was predicted accurately by the Wilson & Thomas method for both Bingham and Casson models. It was possible to eliminate the yield stress of a slurry with the addition of the dispersing agent TSPP. The calcium ion content of the supernatant extracted from the slurries proved to be a indicator of the degree of flocculation. When exposed to extended periods of high shear conditions in the pipeline loop, slurries with clay concentrations of 17% by volume solids or greater exhibited an irreversible increase in apparent viscosity with time. An attempt was made to investigate this irreversible thickening characteristic. Laboratory tests did not reveal any appreciable differences in particle size, electrophoretic mobility, calcium ion concentration or pH with this irreversible change. The shear duration test shows the importance of using the appropriate shear environment when testing high solids concentration kaolin clay slurries

Concentrated kaolin clay slurries are found in a number of industrial operations including mine tailings surface disposal, underground paste backfill, and riverbed dredging. An understanding of the impact of solids concentration and addition of chemical species on slurry rheology is of importance to designers of pipeline transport and waste disposal systems. A project to determine the rheology of an idealized industrial kaolin clay slurry using a concentric cylinder viscometer and an experimental pipeline loop was undertaken. Additional laboratory test work including particle size analysis, slurry pH, calcium ion concentration in the slurry supernatant and particle electrophoretic mobility measurements were completed to aid in the understanding of their effects on the slurry rheology. The slurries were prepared in varying kaolin clay solids concentrations with reverse osmosis water. A flocculant, dihydrated calcium chloride (CaCl2 ¡¤ 2H2O), was added to the reverse osmosis water in concentrations equivalent to those found in typical industrial hard water supply. A dispersant, tetra-sodium pyrophosphate (TSPP, Na4P2O7) was used to disperse the clay particles for selected slurries. It was found that the kaolin clay slurries, in the absence of TSPP, exhibited yield stresses and could be characterized with either the two-parameter Bingham or Casson continuum flow models. Increasing the clay concentration in the slurry, while keeping the mass ratio of flocculant to kaolin constant, increased both the yield and plastic viscosity parameters. There was generally good agreement between the rheological parameters obtained in the Couette flow viscometer and that in the pipeline loop. In slurries for which it was possible to obtain turbulent flow, the transition to turbulent flow was predicted accurately by the Wilson & Thomas method for both Bingham and Casson models. It was possible to eliminate the yield stress of a slurry with the addition of the dispersing agent TSPP. The calcium ion content of the supernatant extracted from the slurries proved to be a indicator of the degree of flocculation. When exposed to extended periods of high shear conditions in the pipeline loop, slurries with clay concentrations of 17% by volume solids or greater exhibited an irreversible increase in apparent viscosity with time. An attempt was made to investigate this irreversible thickening characteristic. Laboratory tests did not reveal any appreciable differences in particle size, electrophoretic mobility, calcium ion concentration or pH with this irreversible change. The shear duration test shows the importance of using the appropriate shear environment when testing high solids concentration kaolin clay slurries

Over the last three decades, mine backfilling has progressively integrated into underground mining operations. The high stresses associated with mining at depth in the Canadian Shield, also requires innovative approaches to mine backfilling to withstand the loading both during and after mining operations. Not only new or modified minefill systems are required, but also new techniques are needed to increase the speed of the mining cycle for optimizing the mining operation. Three major purposes of mine backfill are known as (1) providing safe working condition, (2) maximizing ore recovery and (3) improving underground stability. Therefore, mine backfill has contributed greatly to the economics and environmental aspects of mining industry. / In order to improve the mechanical behaviour of fill, cementitious materials are used. These cementitious materials are expensive. As a result the consumption of these cementitious materials has to be optimized and minimized in a way that the required strength is met. The objective of this research is to investigate a new type of backfill, which is known as gelfill. Gelfill binders usually consist of alkali activators such as sodium silicate and the other cementitious materials. Sodium silicate has been used in waste treatment and activation of artificial pozzolans such as blast furnace slag and fly ash. / The work presented in this thesis is to evaluate the use of sodium silicate in gelfill. Consequently, the influence of mixing time, mixing sequence and curing time are studied on gelfill and silica sand hydraulic backfill. Various tests including unconfined and confined compressive strength were conducted in order to investigate the mechanical behaviour of samples. By conducting mercury intrusion porosimetery (MIP) and scanning electron microscopy (SEM), microstructure and mineralogical properties of specimens were studied. / The result of this thesis demonstrates that gelfill compared with silica sand hydraulic backfill has better mechanical properties. In addition, other variables, including: mixing time and sequence, have a significant effect on gelfill.

Typescript (Photocopy) / Bibliography: leaves 196-205 / 262 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1988?

Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 74-75.

Thesis (Ph.D.) - University of Queensland, 2001. / Includes bibliography.

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xi, 84 p. : ill. (some col.). Includes abstract. Includes bibliographical references.