A dissertation submitted in fulfilment of the requirements for the Magister Technologiae: Engineering: Metallurgical / Kumba Iron Ore’s Sishen mine is located in South Africa’s Northern Cape Province and produces about 40 million tons (Mt) of iron ore per annum. The ore body consists mainly of laminated and massive type hematite ore of which 30 Mt is being beneficiated by Dense Medium Separation (DMS), while the remaining 10 Mt is processed by the jig plant that was added as an expansion to the DMS processing route. The jigs at the jig plant are employed to treat coarse, medium and fine Run of Mine Ore (ROM). Due to the presence of finer particles on the screened ROM, hydrocyclones are employed on the secondary screen that feed the finer jig to produce fines on the overflow that is fed to the thickeners for dewatering by sedimentation, and the formation of clear liquid that can be recycled to the Jig plant. However, it was suspected that a substantial amount of the iron gets lost to the hydrocylone overflow with slimes. These slimes consist of very fine particles (about 90%-45μm) which make treatment with gravity concentration methods difficult. Sishen mine attempts to beneficiate the slimes using Pulsating High Gradient Magnetic Separators (PHGMS). However, PHGMS produce a concentrate consisting of 64.0% iron and 5.0% silica which render the slimes not suitable for pelletizing. Normally the slimes are considered as waste and are rejected to the slimes ponds. Rejecting slimes is not only a loss of resources, but it also poses severe long-term environmental problems. Recovery of iron minerals from the tailings produced in a large iron ore operation is of importance as it will result in environmental and economic benefits which indicate the importance of utilising those accumulated fines. / n/a

Les cités ouvrières d'origine minière voient le jour en Algérie dans la seconde moitie du XIXe siècle. Elles sont le fait d'une industrie extractive de fer mise au point par la colonisation pour soutenir le développement industriel sidérurgique en France. Grâce au minerai pur Algérien, Mokta-el-Hadid devient une puissante compagnie minière qui n'hésite pas à réorganiser le marché du fer en France. Le patronat français qui importe en Algérie ses moyens de production, importe par la même occasion ses architectures et ses modes d'habiter. Ce travail de thèse propose une réflexion approfondie sur l'histoire de l'industrie minière coloniale en Algérie et son mode d'établissement urbain. Il évoque les conditions pratiques et idéologiques des modalités d'action du patronat colonial sur les groupes sociaux et leur espace de vie. Les cités ouvrières, construites en Algérie entre 1870 et 1940, répondent à des considérations à la fois économiques, structurées par une morale patronale et coloniales, marquées par un établissement pérenne d'une population ouvrière européenne en Algérie. L'analyse de l'espace urbain de la cité minière de Béni-Saf, dans le nord-ouest algérien, montre une intéressante richesse de typologie de bâti. Sa morphologie urbaine est largement marquée par les articulations entre la reproduction de l'organisation du travail dans la mine, le développement des forces ouvrières et la prégnance de l'idéologie colonialiste. L'urbanisation accélérée de l'ère post-coloniale marque encore plus radicalement cette morphologie par la volumétrie des nouvelles constructions, le mode de vie social et la politique non conservatrice du patrimoine bâti. Il convient donc de s'interroger sur les pratiques et la représentation du patrimoine industriel colonial en Algérie. / Mining company towns emerged in Algeria in the second half of the nineteenth century. They were established by an extractive iron industry developed by colonization to support the development of steel industry in France. Thanks to the Algerian pure iron-ore, Mokta-el-Hadid became a powerful mining company, which did not hesitate to reorganize the iron market in France. French employers imported to Algeria their production means and at the same time their architectures and their ways of inhabiting. This thesis proposes a deep reflection on the history of the colonial mining industry in Algeria and its urban settlement modes. It evokes the ideological and practical conditions of the modes of action of colonial employers on social groups and their living space. The company towns built in Algeria between 1870 and 1940 responded to economic considerations framed by entrepreneurial and colonial morals, marked by the permanent establishment of a European working population in Algeria. Analysis of the urban space of the mining town of Beni-Saf, in northwest Algeria, shows a wealth interesting of constructive typologies. Its urban morphology is largely characterized by the articulation between the reproduction of the working mine organisation, the development of working forces and the pervasiveness of colonialist ideology. The rapid urbanization of the post-colonial time marks more radically this morphology by the volumetry of new buildings, the social lifestyle and the non-conservative policy of historical buildings. It is thus necessary to examine the practices and the representations of colonial industrial heritage in Algeria.

[pt] O presente trabalho estudou o comportamento de rejeitos de minério de ferro e de ouro, reforçados com fibras de polipropileno, com o objetivo da aplicabilidade destes compósitos em aterros (pilhas) de rejeitos de mineração. As fibras foram distribuídas de forma aleatória nos rejeitos (matriz) em um teor de 0.5 por cento em relação ao peso seco da matriz. Os rejeitos de minério de ferro e de ouro são classificados como uma areia siltosa e uma argila siltosa, respectivamente. O programa experimental consistiu em ensaios triaxiais convencionais drenados e não drenados (tensões efetivas de confinamento de 50, 100, 200 e 400 kPa) em amostras não reforçados e reforçados com fibras. Ensaios de cisalhamento direto com superfície polida (tensões normais de 25, 50, 100, 200 e 400 kPa) foram realizados para determinar a influência do reforço na fase residual dos compósitos. Ensaios de Microscopia Eletrônica de Varredura (MEV) foram realizados para visualizar a interação fibra-matriz. A análise global dos resultados permitiu mostrar que fibras de polipropileno não modificam o comportamento elastoplástico do rejeito de minério de ferro, porém no rejeito de minério de ouro o comportamento muda para elastoplástico de enrijecimento. A resistência ao cisalhamento incrementou em ambos os rejeitos reforçados, com um ganho mínimo equivalente ao dobro da tensão cisalhante dos rejeitos sem reforço. Com relação à variação volumétrica, o rejeito de minério de ferro apresenta um comportamento dilatante e a adição de fibras incrementa esse comportamento. No rejeito de minério de ouro observa-se que a tendência volumétrica inicial é de contração e depois apresenta uma leve dilatância, porém, com a adição de fibras, o comportamento dilatante é eliminado. Em conclusão, a aplicabilidade das fibras de polipropileno se mostra como alternativa de reforço e melhoria do comportamento geotécnico dos rejeitos de mineração estudados. / [en] The objective of this work is to study the behavior of iron and gold mine tailings reinforced with polypropylene fibers with the objective of the applicability of these composites in landfills (piles) of mine tailings. The fibers were randomly distributed in the mine tailings (matrix), where was used a content of 0.5 percent in relation to the dry weight of the matrix. The iron and gold mine tailings are classified as a silty sand and a silty clay, respectively. The experimental program consisted of conventional drained and undrained triaxial tests (effective confinement stresses of 50, 100, 200 and 400 kPa) in non-reinforced and reinforced samples. Direct shear tests with a polished surface (normal stresses of 25, 50, 100, 200 and 400 kPa) were performed to determine the influence of reinforcement on the residual phase of the composites. Scanning Electron Microscopy (SEM) tests were performed to visualize the fiber-matrix interaction. The global analysis of the results allowed to show that polypropylene fibers do not modify the elastoplastic behavior of the iron mine tailings, but in the gold mine tailings the behavior changes to the strain hardening elastoplastic. Shear strength increased in both reinforced tailings, with a minimum gain equivalent to twice the shear stress of non-reinforced tailings. The strength parameters in the drained, undrained and residual condition of both mine tailings were increased with the addition of fiber. Regarding the volumetric variation, the iron mine tailings exhibits a dilative behavior and the fiber addition increases this behavior. In the gold mine tailings, it is observed that the initial volumetric tendency is contractive and then presents a slight dilatancy, however, with the fiber addition, the dilative behavior is eliminated. In conclusion, the applicability of the polypropylene fibers is showed as an alternative of reinforcement and improvement of the geotechnical behavior of the studied tailings.