Extremely huge quantities of mined ore materials are processed annually to obtain the various types of minerals being the barebones of industry. Impounding the waste materials (tailings) of the mined minerals behind a raised embankment is the major and most common method used for the disposal of theses materials. Due to its execution simplicity and low cost, the upstream raising method has been the most common method used for retaining the disposed tailings in spite of being the most failure-vulnerable one. The sophisticated hydromechanocal behavior of the upstream tailings disposal facilities (UTDFs) during the staged construction makes the traditional approaches of consolidation, stability, and seepage analyses inefficient for producing accurate and, in many situations, correct design and evaluation of the UTDFs. The major objective of this thesis is to propose a thorough procedure for realistically evaluating the hydromechanical response of the UTDFs during their staged construction. The procedure incorporates a numerical model that reflects the combination of important realistic features of the UTDFs, namely (i) the partially saturated flow characteristics under the transient state dominating the facility throughout its operation/construction life; (ii) the two dimensional consolidation response of the facility components under both the partially and fully saturated cases considering (a) the full coupled response between the fluid and the solid phases and (b) the large deformation-nature of the tailings; as well as (iii) the appropriate mechanical behavior of the facility materials including a model that can detect the inception of liquefaction in the liquefaction-susceptible zones of the facility. The influences of a number of operational/construction measures that have been reportedly critical for the stability of the UTDFs are investigated in the light of the proposed model. Moreover, the inappropriateness of the traditional approaches for realistically evaluating the UTDF hydromechanical response during its staged construction is substantiated in the analyses carried out in this work. / The conclusions and recommendations drawn from this thesis are paramount not only for the feasibility, preliminary design and risk assessment studies of the UTDF during its operation/construction life but also for the on going analytical investigations and monitoring/instrumentations plans carried out throughout such life.

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This master thesis has been conducted through cooperation between Elforsk, Uppsala University and Tsinghua University in Beijing. Ashele Tailings Dam, located in Haba Town, Xianjing Province, China, is designed and used for high sulphur tailings. Because of a new mineral separation technique, the dam is now also being filled with low sulphur tailings. Since the dam was not originally designed for the new tailings materials, the seepage and stress-strain analyses of the dam need to be re-evaluated and refined. The Ashele Ltd. is also planning on building a new dam to meet its growing need for tailings deposit capacity. This dam will be used for the new low sulphur tailings and a thorough analysis of the dam will have to be performed.The purpose of this thesis is to re-evaluate the analyses of the seepage and stress-strain in the old dam and to perform the same type of analyses on the newdam. Numerical analyses of the seepage, solute transport and strain-stress in the dam are performed, using the physical and mechanical properties of the tailings materials. It is shown, that the construction of the new tailings dam, will have a good effect on the seepage and therefore also solute transport. The results also show that theseepage, solute transport, stress and deformation are depending on the amount ofwater in the tailings pond and that a lower water level has a positive effect on all thestudied variables.

Thesis (Ph.D. (Civil and Biosystems Engineering)) -- University of Pretoria, 2009. / Summary in English. Includes bibliographical references.

Thesis (MEng.(Geotechnical Engineering)(Civil and Biosystems Engineering)) -- University of Pretoria, 2007. / Thesis in English. Includes bibliographical references.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. / The research report summarises the theory of consolidation, for both linear infinitesimal strain, and for non-linear finite strain. The non-linear finite strain theory isadopted in a computer program to model the building of a tailings dam by thin layers. This program provides the pore water pressure profile over the depth of the deposit, as well as the settlement of the deposit. Making use of the program and the consolidation properties of five mining residues and two industrial residues, the build up of excess pore water pressures is modelled for different rates of deposition of the waste products. These results are used in determining how the rate of deposition affects the stability of the outer slope of a tailings dam. Also, the difference in the stored volume in a dam is investigated, based on different drainage condltions and rates of deposition. / Andrew Chakane 2018

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. / The reliability of using isotropically consolidated specimens in the laboratory determination of liquefaction characteristics of cohesionless sands, as is common practice today, is evaluated. Two series of triaxial tests involved the conventional undrained loading of isotropically and anisotropically consolidated specimens. The third series of tests utilized anisotropically consolidated specimens loaded by following special undrained stress paths. Test results revealed that liquefaction characteristics obtained from isotropically and anisotropically consolidated specimens are different. The effective angles of friction mobilized at peak shear stress and at steady state were greater for anisotropically consolidated specimens. Loading stress path is seen to have no effect on the liquefaction characteristics derived from conventional loading of anisotropically consolidated specimens. The critical stress ratio line is observed to be the line determining the initiation of liquefaction so that any stress path attempting to cross this line, regardless of direction of approach, immediately shows strain-softening behavior leading to liquefaction. / AC 2018

In general, tailings dams are expected to seep. Anomalous seepage, especially when induced by internal erosion, is a major concern for owners and operators. The long established techniques for monitoring water seepage provide sparse information which may not be sufficient to detect and map the seepage path. Hence, there exists a great need for non-invasive techniques that would be sensitive to changing seepage conditions. The non-invasive nature of the techniques is particularly important because drilling and other penetrating (invasive) investigation methods are normally avoided. / Non-invasive techniques such as self-potential and high-resolution resistivity have been significantly improved in the past decade and have been successfully used for water retention dam investigation and monitoring. The main difficulty in the use of these techniques in monitoring sulfide rich tailings dams is the presence of electrochemical potentials that renders the interpretation of the acquired self-potential data difficult. / Numerical modelling is one of the latest methods in interpreting self-potential anomalies induced by liquid flow. But, in order to model streaming potentials several parameters need to be measured or estimated; (1) the hydraulic driving force and the hydraulic conductivity are required to solve for the hydraulic pressure distribution; (2) the cross-coupling conductivity distribution is needed to calculate the conduction current source parameter; and (3) the resistivity distribution is needed to determine the resulting potential distribution. / The zeta-potential and the resistivity of three pyrite rich tailings from the Abitibi region in Quebec were measured over the pH range 2 to 5 in different KCl aqueous solutions for the purpose of estimating the magnitude of electrokinetic effect induced by mine water seepage and the electrical resistivity variation induced by particle migration. The experimental and theoretical results obtained in the present study are pertinent to the interpretation of self-potential data. The zeta-potential was found to vary from -27 to -2 mV and the resistivity of the tailings was found to increase when fine particles are eroded.