Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Northern Cape Province of South Africa has played host to numerous mining activities for over a century. To date, most of the mining activity has ceased, leaving the area laden with derelict mine sites and unlined tailings dumps. One such site is the Spektakel mine situated to the west of the town of Springbok. The unlined copper and sulphide rich tailings at the site have the potential to leach elevated concentrations of copper and acidic water into the Buffels River downslope of the site. This poses a threat to the surrounding communities that rely mainly on the river to supply water for drinking, livestock and irrigation. The soil surrounding the tailings dumps was characterised in terms of its mineralogical and chemical properties. The results indicate that the soil contains elevated concentrations of Cu2+, which is bound in the soil in the form of the secondary copper hydroxy mineral atacamite (Cu2(OH)3Cl). No other secondary copper minerals were identified at the site. Analysis of the solution present on the surface of the tailings dumps indicate that the tailings are the main source of the high Cu2+, Mg2+ and SO42- concentrations observed in the surrounding soils. As this solution migrates through the tailings dumps, into the soil, it accumulates Cl- through halite dissolution. The resulting acidic Cu2+, Mg2+, SO42- and Cl- solution reacts with the calcite in the soil, replacing it with atacamite. To determine why only a copper chloride mineral formed in the sulphate rich environment a synthetic solution with the composition of a solution in equilibrium with the soil was evaporated, both in the presence and absence of calcite. The results indicate that when the solution comes into contact with calcite, atacamite immediately precipitated, removing the Cu2+ from the solution. In the absence of calcite Cu2+ remains conservative, accumulating in the solution without precipitating a copper sulphate mineral. This establishes that the elevated Mg2+ concentration of the solution induces the formation MgSO4 aqueous complexes that reduce the activity of free sulphate, thus restricting copper sulphate mineral formation. The results from the soil characterization indicate that the atacamite stabilization mechanisms (circumneutral pH, high Cl- concentration and calcite) in the soil are diminishing. During sporadic rain events the acidic tailings solutions dissolve the calcite and temporarily reduce the Cl- concentration of the soil. To determine how these decreases will influence Cu2+ mobility in the soil, the stability of atacamite was tested by reducing the pH both in the presence and the absence of chloride. The results indicate that an elevated Cl- concentration and a pH > 6 stabilizes atacamite. A decrease in either of these parameters destabilizes atacamite and favours its dissolution. The study concludes that the current chemical conditions in the soil at Spektakel favour the stability of atacamite. However, continued sporadic rain events will reduce the Cl- concentration in the soil by increasing the SO42- concentration. This acidic solution will dissolve the calcite in the soil, thus reducing the buffering capacity of the soil, leading to the instability of atacamite, resulting in the leaching of large quantities of Cu2+ into the surrounding water bodies. / AFRIKAANSE OPSOMMING: Die mynbou bedryf was die ekonomiese dryfkrag van die Noord-Kaap Provinsie van Suid-Afrika vir meer as ‘n eeu. Die area was die gasheer vir ‘n verskeidenheid mynbou aktiwiteite tot die mynmaatskappye besluit het om mynproduksie te staak en die gebied te verlaat. Die mynmaatskappye het geen rehabilitasie aan die myne en mynhope verrig nie. Die verlate myne lê verspreid in die area met oop mynhope wat koper en ander swaar metale in die grond, sowel as in die water, na omliggende areas kan versprei. Een van dié verlate myne is die Spektakel myn 40 km wes van Springbok. Die mynhope by Spektakel kan moontlik koper en ander swaar metale in die Buffelsrivier, wat langs die myn verby loop, loog. Dit dien as ‘n bedreiging vir die omliggende gemeenskappe wat staatmaak op die water vir drinkwater en besproeiing. Die grond rondom die mynhope was ge-analiseer om te bepaal hoe erg ‘n bedreiging die mynhope vir die omgewing is. Die resultate dui daarop dat die grond hoë konsentrasies Cu2+ bevat wat vasgebind is in die sekondêre koper mineral atakamiet (Cu2(OH)3Cl). Geen ander sekondêre koper minerale is in die grond geïdentifiseer. Die analise van die oplossing wat bo-op die mynhoop aangetref is dui aan dat dié oplossing suur en gekonsentreerd is t.o.v. Cu2+, Mg2+ en SO42-. Terwyl die oplossing deur die mynhoop migreer los dit haliet in die grond op wat Cl- tot die oplossing byvoeg. Wanneer hierdie suur en Cu2+, Mg2+, SO42- en Cl- ryke oplossing met die kalsiet in die grond reageer word die kalsiet vervang met atakamiet (Garrels en Stine, 1948). Om vas te stel waarom slegs 'n koperchloried mineraal vorm in die sulfaat ryke grond was ‘n oplossing, met ‘n samestelling soortgelyk aan 'n oplossing in ewewig met die grond, verdamp in beide die teenwoordigheid en afwesigheid van kalsiet. Die resultate van die eksperiment dui daarop dat wanneer die oplossing in kontak kom met kalsiet atakamiet onmiddellik neerslaan en Cu2+ uit die oplossing verwyder. In die afwesigheid van kalsiet bly Cu2+ konserwatief in die oplossing; die Cu2+ hoop op in die oplossing en slaan nooit neer nie. Daar is vasgestel dat die verhoogde Mg2+ in die grondoplossing MgSO4 water komplekse vorm wat die aktiwiteit van SO42- verlaag en verhoed dat kopersulfaat minerale kan vorm. Verdere navorsing dui aan dat die chemiese meganismes wat atakamiet in die grond stabiliseer besig is om te kwyn. Gedurende sporadiese reën buie word die kalsiet in die grond opgelos deur die suur mynhoop oplossings wat die pH van die grond verlaag. Die mynhoop oplossing verryk ook die grond t.o.v SO42- wat die Cl- konsentrasie verlaag. Om te bepaal hoe hierdie afname in Cl- konsentrasie en pH die migrasie van Cu2+ beïnvloed was atakamiet oplossbaarheid bepaal. Atakamiet was onderskeidelik geplaas in ‘n suiwer water en chloried oplossing tewyl die pH verlaag was om te bepaal hoe atakamiet oplos in elk van die oplossings. Die resultate dui aan dat 'n verhoogde Cl- konsentrasie en pH > 6 atakamiet stabiliseer. Die afname van beide hierdie veranderlikes het veroorsaak dat atakamiet makliker ontbind en Cu2+ vrystel. Die gevolgtrekking van die studie is dat die huidige chemiese toestande in die grond by Spektakel gunstig is vir die stabiliteit van atakamiet. Met sporadiese reën buie neem die Cl- konsentrasie in die grond af en los kalsiet op. Hierdie afname in pH en Cl- konsentrasie maak atakamiet meer onstabiel wat gevolglik Cu2+ in die grond en water rondom Spektakel vrystel.

Research was conducted at Cyprus Pima Mine, an open pit copper mine located southwest of Tucson, Arizona, in 1980 and 1981 to study the establishment of annual and perennial grasses on the slopes of copper mine tailing ponds. In 1980, the north and south slope exposures were hydroseeded with barley (Hordeum vulgare L.). Plots were capped with topsoil prior to planting or left uncapped, and mulched with wheat straw after planting or left unmulched. Desert soil was classified as Palos Verdes-Sonoita Complex and Detrital-Sonoita Complex. Barley provided a quick, temporary cover and served as a mulch for later plantings. The number of seedlings established was the same for both exposures. Barley grew taller on the north slope possibly due to cooler temperatures. Barley growth was more vigorous on mulched areas. In 1981, the same north and south slopes were hydroseeded with Lehmann lovegrass (Eragrostis lehmanniana Nees.), buffel grass (Pennisetum cilare (L.) Link), blue panicgrass (Panicum antidotale Retz.) and bermudagrass (Cynodon dactylon (L.) Pers.). Prior to planting perennials, barley residue was incorporated into the slopes using a spike-tooth chain drag and a sheepfoot roller, or was left unincorporated. Incorporation of barley residue aided in its breakdown and helped prepare a good seedbed. The spike-tooth chain drag produced better growth than the sheepfoot roller, possibly due to excessive soil compaction with the sheepfoot roller. Capping tailing slopes with desert soil produced the most significant improvements in barley and perennial grass growth. Soil analyses of pure tailing and capped tailing revealed both were low in nitrogen and phosphorus. All plots were amended with these nutrients. Organic matter, although low for both samples, was higher in the capped tailing sample. Organic matter improves soil structure and provides nutrients and its increased presence may have been the main reason for improved growth on capped slopes.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2017 / The research was driven by the need to optimise the Ruashi Mining operation to prevent further high-grading without destroying the value of the mine. Ruashi Mining incurred a five-year stripping backlog caused by the drive to reduce costs. As a result of this, a decline in metal production was imminent in the subsequent years. The study was conducted mainly using SimSched Direct Block Scheduler (SimSched DBS) in comparison with schedules from Datamine Net Present Value Scheduler (NPVS) and MineSched. The scenarios investigated have shown that running a mine based on break-even cut-off grade does not optimise the net present value of an operation as shown through the results of Ruashi Mining. The research also proved that royalty affects the cut-off grade for Ruashi Mining, and cannot be ignored. The proper scheduling of wasting stripping resulting from cut-off grade optimisation has contributed to a timeous exposure of high grade to avert the decline in metal production. All the three scenarios have shown that high grade ore can be availed on time, thus producing a smooth metal output for the life of mine. Cut-off grade optimisation is very crucial for any mining organisation as it is the main driver of value. Ore reserves are important in the determination of a company’s share price. High cut-off grade results in fewer reserves, and vice versa. Since mineral reserves are the source of revenue, therefore, the higher the reserves, the higher the revenue. Low cut-off grade may result in the processing of material that does not give high profit at the beginning of the life of mine. This, therefore, lowers the mining company’s net present value. This makes it imperative to optimise the cut-off grade during the mine life in order to optimise the net present value. During mining operations, there are various stakeholders whose interests must be considered during cut-off grade optimisation because they derive many benefits from the mine. These stakeholders include shareholders, employees, government, the community and non-governmental organisations. Cut-off grade optimisation has shown that there is an opportunity to improve the net present value of Ruashi Mining. SimSched gives a higher net present value (NPV) compared to the current Ruashi life of mine schedule. This indicates that SimSched can be used to improve the NPV for Ruashi by producing an optimised schedule. It is important to note though that there is need for the software to have provisions to take into account the initial stockpile status so that there is a holistic approach to the schedule optimisation. The grade-tonnage curve is steeper closer to zero implying that a small change in cut-off grade has a huge impact on reserves. Based on the results of the study it was clear that optimisation in SimSched DBS results in a steeply declining cut-off grade policy compared to NPVS. In addition, optimisation in SimSched leads to highly accelerated mining rate and massive stockpiling. Royalty is a cost which has to be incorporated in cut-off grade optimisation. The study has shown that the cut-off grade for Ruashi is increased by 19.8%. Ignoring royalty may result in overvaluing of an operation. Environmental considerations favour the optimisation of the use of the mieral resources. Consideration of environmental costs lowered the cut-off grade for Ruashi by 16%. / MT 2017

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Copper is the mainstay of the Zambian economy. From the inception of mining activities in the 1920s, it has accounted for the majority of the country‟s exports and foreign earnings. However, most people are of the view that its contribution to development programmes is disproportionate, well below their expectations. They attribute the contemporary failure to copper price volatility, international market forces, ownership, government ineptitude and the consequences of neoliberalism. Given the large expense involved in establishing and running copper mines, the country depends heavily on foreign capital. A big proportion of the copper that is mined in Zambia is sold in an unprocessed state denying the country additional revenue. This study assesses both the role of copper mining in the economic history of Zambia and its role in contemporary development as perceived and understood by current university-educated job market entrants on the Zambian Copperbelt, their educators and other commentators with work experience in the sector. / Theses (M.Dev.Studies)--University of KwaZulu-Natal, Durban, 2014.

Orientador: Laura Maria Mariscal Ottoboni / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T23:22:56Z (GMT). No. of bitstreams: 1 Rodrigues_VivianeDrumond_D.pdf: 5631358 bytes, checksum: 6072655858120e417b92336ddd538828 (MD5) Previous issue date: 2014 / Resumo: O conhecimento acerca da diversidade microbiana associada a ambientes de mina é limitado, apesar da importância que alguns micro-organismos podem ter no processo de biolixiviação e biorremediação ambiental. Adicionalmente, micro-organismos que vivem em condições inóspitas, como os diferentes ambientes de mina, vêm despertando interesse cada vez maior por possuírem enzimas de interesse industrial. Neste sendido, a análise da biodiversidade funcional e estrutural de micro-organismos presentes em ambientes de mina é de fundamental importância para entender a estrutura e a complexidade das comunidades microbianas em ambientes extremos. Neste trabalho a diversidade microbiana foi analisada em diversos ambientes da mina de cobre do Sossego, localizada em Canaã dos Carajás, sudeste do Pará por abordagens dependentes e independentes de cultivo. A composição taxonômica associada a ambientes da mina do Sossego: taludes (estruturas geotécnicas) e entorno da drenagem dos depósitos de Sossego (T-SO1, T-SO2, ED-SO1, ED-SO2) e Sequeirinho (T-SE1, T-SE2, ED-SE1, ED-SE2) foi avaliada por pirosequenciamento do gene de rRNA 16S. Os resultados indicaram que a comunidade de bactérias de talude é distinta do entorno da drenagem e o conteúdo de matéria orgânica e maior disponibilidade de água foram os principais fatores para as diferenças. Os principais táxons responsáveis pelas diferenças foram Acidobacteria, Chloroflexi, Gammaproteobacteria e Firmicutes. Por meio de técnicas dependentes de cultivo, 64 bactérias heterotróficas foram isoladas a partir das amostras SO5, SO6, SO7 e SO9. Estes isolados foram identificados e avaliados quanto à capacidade de produção de enzimas (hidrolases, monoxigenases, sulfoxidases e betalactamase) e compostos (sideróforos, biossurfactantes e antimicrobianos). Foram identificadas bactérias afiliadas aos seguintes gêneros: Acidovorax, Acinetobacter, Brevundimonas, Cupriavidus, Curtobacterium, Kocuria, Lysinibacillus, Pseudomonas, Roseomonas, Ralstonia, Stenotrophomonas e Bacillus, sendo o último respresentado por 43 isolados. Com relação à triagem funcional, 95% das bactérias foram capazes de produzir sideróforos, 58% biossurfactantes, 69% betalactamases, 50% antimicrobianos, 53% proteases, 75% esterases, 20% monoxigenases e três isolados (SO5.4, SO5.9 e SO6.2) apresentaram oxidação seletiva para sulfetos orgânicos. A partir de amostras de drenagem (SO5, SO6 e SO7) foram obtidos consórcios de micro-organismos oxidantes de ferro. Estes consórcios foram testados com relação à capacidade de biolixiviação da calcopirita e foram mais eficientes para a dissolução do cobre do que Acidithiobacillus ferrooxidans LR. A identificação dos micro-organismos presentes nos consórcios foi realizada por eletroforese em gel de gradiente desnaturante (DGGE) e as bandas mais evidentes foram classificadas em Bacillus sp., Delftia sp., Phenylobacterium sp. e Methylobacterium sp. A comunidade de bactérias na mina de cobre do Sossego foi diversa e complexa. Estes resultados mostram um inventário da microbiota em diferentes ambientes da mina do Sossego e as enzimas e compostos obtidos destas bactérias poderão ser utilizadas em processos e tecnologias que permitam a recuperação de metais, como a biolixiviação e biorremediação ou em outras aplicações industriais / Abstract: The knowledge concerning microbial diversity associated with mine environments is limited, despite the importance that some microorganisms can have on environmental bioremediation and bioleaching process. Additionally, microorganisms that live in inhospitable conditions, such as different mine environments, have attracted growing interest because they could have enzymes with industrial applications. In this way, structural and functional biodiversity analysis in mine environments is an important issue to understand the structure and complexity of the microbial communities in extreme environments. The present work shows a microbial diversity analyses in some cooper mine environments of Sossego Mine localized in Canaã dos Carajás mineral province, Pará state, Brazil. The bacterial taxonomic composition associated with Sossego cooper mine: slopes (geotechnical structures) and surrounding drainage of Sossego and Sequeirinho deposits was evaluated using pyrosequencing of 16S rRNA gene. The results indicated slope bacterial community differs from surrounding drainage and organic matter content and higher water availably were the main factors of these differences. The foremost taxons accountable by those differences were Acidobacteria, Chloroflexi, Gammaproteobacteria and Firmicutes. Sixty four bacteria were isolated using culture-dependent methods from SO5, SO6, SO7 and SO9 samples. These bacteria were identified and evaluated concerning the capability of enzyme production (hydrolase, betalactamase, monooxygenase and sulphoxidases) and compounds (siderophore, biosurfactants and antimicrobials). It was identified bacteria related with the followed genera: Acidovorax, Acinetobacter, Brevundimonas, Cupriavidus, Curtobacterium, Kocuria, Lysinibacillus, Pseudomonas, Roseomonas, Ralstonia, Stenotrophomonas and Bacillus, the last one showed 43 isolates. In relation with functional screening, 95% of bacteria were capable to produce siderophores, 58% to produce biosurfactants, 69% betalactamases, 50% antimicrobials, 53% proteases, 75% sterases, 20% monooxygenases and three strains (SO5.4, SO5.9 and SO6.2) exhibited selective oxidation for organic sulphides. Iron oxidizing microorganism consortia were obtained from drainage samples and were tested according with its ability for bioleaching of chalcopyrite. The consortia obtained from SO5, SO6, and SO7 samples were more efficient than Acidithiobacillus ferrooxidans LR regarding bioleaching of copper from chalcopyrite. The identification of microorganism presented in the consortia was performed using DGGE technique and the more evident bands were classified as Bacillus sp., Delftia sp., Phenylobacterium sp. and Methylobacterium sp. The bacterial community in Sossego cooper mine was diverse and complex. These results showed a microbiota inventory in distinct mine environments and enzymes and compounds obtained from those bacteria could be used in new processes and technologies that allow to recovery metals as bioleaching, bioremediation or others industrial applications / Doutorado / Genetica de Microorganismos / Doutora em Genética e Biologia Molecular

Orientadores: Lena Virginia Soares Monteiro, Roberto Perez Xavier / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-19T17:30:40Z (GMT). No. of bitstreams: 1 Pestilho_AndreLuizSilva_M.pdf: 3902456 bytes, checksum: 1316b1f2f664966b7e4c2d9a46a528d2 (MD5) Previous issue date: 2011 / Resumo: Localizados na porção norte da Província Mineral de Carajás, a uma distância de cerca de 8 km do depósito de óxido de ferro-cobre-ouro de Sossego, estão os depósitos de cobre Alvo Bacaba e Alvo Castanha. Esses depósitos encontram-se ao longo de uma zona de cizalhamento regional de cerca de 60 km de extensão, no limite entre o Supergrupo Itacaúnas e seu embasamento representados principalmente pelos migmatitos do complexo Xingu. O Alvo Bacaba é hospedado pelo granito Serra Dourada e pelo tonalito Bacaba, enquanto o Alvo Castanha é Ambos os depósitos exibem amplas zonas de alteração hidrotermal que compreendem quase que respectivamente a albitização, a escapolitização, a formação de óxidos de ferro, a alteração sódico-cálcica, a alteração potássica, a formação de turmalina, a sericitização, a cloritização, a epidotização e a carbonatização, embora estes depósitos mostrem diferenças, como a alteração sódico-cálcica que apesar de ser bem desenvolvida no Alvo Castanha, é quase inexistente no Alvo Bacaba, onde apenas ocorre como alteração nos gabros. Também o Alvo Bacaba possui uma associação de minerais distintas, composta por calcopirita±pirita±bornita, enquanto o Alvo Castanha exibe a associação calcopirita±pirrotita±pirita. Informações sobre evolução paragenética e dados de isótopos estáveis indicam que os depósitos Alvo Bacaba e Alvo Castanha evoluíram durante progressivo resfriamento. Entretanto, esta redução com relação à evolução paragenética foi maior no Alvo Bacaba do que no Alvo Castanha, e a fugacidade de oxigênio foi mantida alta no Alvo Bacaba. A temperatura de deposição do minério estimada para o Alvo Bacaba pode ter ocorrido entre 220 °C e 410 °C, enquanto no Alvo Castanha esta teria ocorrido entre 350 °C e 420 °C. A evolução isotópica do Alvo Bacaba é similar àquela caracterizada para o depósito de Sossego, com uma redução acentuada da temperatura acompanhada por um decréscimo no valor de ?18O e acréscimo no valor de ?D e evidências de misturas de fluido juvenil e de fonte não magmática. Já para o Alvo Castanha, as composições isotópicas dos fluidos hidrotermais indicam a predominância de uma fonte magmática. Estas características e similaridades com aquelas de Sossego podem apontar para uma contribuição de águas magmáticas e oceânicas no sistema hidrotermal que originou todos estes depósitos / Abstract: The Alvo Bacaba and Alvo Castanha copper deposits are located at the northern part of the Carajás Mineral Province, at a distant radius of about 8 km from the Sossego iron oxide-copper-gold deposit. These deposits occur along a regional shear zone 60 km wide, in the limit between the Itacaiúnas Supergroup and its basement represented mainly by migmatites of the Xingu Complex. Both deposits exhibits widespread hydrothermal alteration zones comprising albitization, scapolitization, iron oxide formation, sodic-calcic alteration, potassic alteration, tourmaline formation, sericitization, epidotization and carbonatization, although these two deposits show differences like sodic-calcic alteration, which is well developed in Alvo Castanha, but it is almost inexistant in Alvo Bacaba, being present only in its altered gabbros. Also the Alvo Bacaba shows ore minerals association essencialy composed by chalcopyrite±pyrite±bornite while the Alvo Castanha shows the association of chalcopyrite±pyrrhotite±pyrite. Paragenesis and stable isotope data indicate that the Alvo Bacaba and Alvo Castanha deposits have evolved with temperature decrease. However, the temperature drop in relation to the hydrothermal alteration succession was greater in Alvo Bacaba than the Alvo Castanha, and the oxygen fugacity was kept higher at Alvo Bacaba. The estimated temperature for ore deposition in the Alvo Bacaba was between 220 °C and 410 °C, while the Alvo Castanha it would have occurred between 350 °C and 420 °C. The isotopic evolution of the Alvo Bacaba is similar to that characterized for the Sossego deposit, with a steep temperature reduction accompanied by decrease of ?18O and increase of ?D values and fluid mixing evidences. In the Alvo Castanha, isotopic compositions of the hydrothermal fluids indicate predominance of magmatic sources. These characteristics and its similarities with those of the Sossego deposit could point to a contribution of magmatic and ocean waters in the hydrothermal system that originated all deposits / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

Doctorat en sciences politiques / info:eu-repo/semantics/nonPublished