Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1911. / The entire thesis text is included in file. Typescript. Illustrated by authors. Title from title screen of thesis/dissertation PDF file (viewed February 27, 2009)

The oxidation of sulfidic mine tailings and subsequent acid and salt accumulation results in acid drainage and poses a severe reclamation problem. The objectives of this study were to quantify the processes leading to these problems and propose feasible solutions. Characterization of 120 sulfidic surface samples, collected from the Sullivan mine tailings ponds, was carried out for dominant physiological groups of microorganisms, sulfur forms, water and acid extractable cations qualitative physical characteristics, pH, conductivity, organic matter and moisture content. Acid tolerant fungi and iron, sulfur and acid tolerant heterotrophic bacteria were enumerated by the most-probable-number technique. Iron bacteria (Thiobacillus ferrooxidans) occurred often and can be implicated as the cause of Fe⁺² oxidation in samples not buffered at near neutral pH values by bases. Sulfur bacteria (thiobacillus species were commonly found and classified as T. thioparus, T. neapolitanus, or T. thiooxidans. A pH-dependent succession of these thiobacilli occurs in the tailings. Acid tolerant heterotrophic bacteria populations were highly correlated with those of the thiobacilli suggesting a symbiotic relationship, particularly in samples with pH >2.5. The numbers of acid tolerant fungi tended to increase proportionally with oxidation, suggesting increased colonization with time. Chemical analysis for major sulfur forms indicates that iron mono- sulfide oxidation is rapid resulting in the formation and persistence of Fe⁺³ (as amorphous Fe oxyhydroxides in mineralogical analysis) and elemental sulfur. Some accumulation of other oxidizable sulfur forms is indicated by the high levels of total oxidizable sulfur. A portion of this sulfur not accounted for by CS₂ extractable elemental sulfur may be present as amorphous elemental sulfur. The oxidation of elemental sulfur and other sulfur intermediates to sulfate is pronounced in the surface 0-2 cm based on the laboratory oxidation of a bulk tailings sample. Mineralogical analysis shows that gypsum is the predominant sulfate containing mineral at basic to slightly acid pH values. Under moderately to strongly acid conditions, jarosite type minerals occurred in high amounts. Mineralogical analysis also showed that the decomposition of basic minerals and chlorite occurred initially, with the dissolution of micas and K-feldspars being less rapid. The absence of detectable kaolinite or other Al silicate residues indicates that alumino-silicate dissolution may be congruent. Mineralogical results showing dissolution of minerals is supported by general increases in water extractable cations (including Fe, Al, Ca, Mg, K and Na) and decreases in these same acid extractable cations as weathering proceeds. These processes ultimately result in a highly oxidized surface in which acid production is slow. It is suggested that erosional processes be inhibited where an oxidized surface exists to prevent the exposure of reduced tailings beneath the surface. Furthermore, steps should be taken to minimize the addition of fresh tailings over oxidized surfaces. The use of correlations between the qualitative physical characteristics texture, structure and color, obtained in this study, can serve as guides to estimating the degree of tailings oxidation in the field. If more precision is required, the colorimetric determination of CS₂ extractable elemental sulfur is suggested, particularly on the more oxidized samples. Proper management of the tailings to maintain present oxidized surfaces should reduce the acid drainage considerably until reclamation is undertaken. The quantification of the changes in tailings properties with increases in weathering can be useful in evaluating reclamation strategies. / Land and Food Systems, Faculty of / Graduate

As a result of the mining that has taken place over the last century in South Africa, many towns and cities have developed around mining hubs, the most significant of these being the city of Johannesburg. Over the years, residential areas have grown around these mine sites, even well after decommissioning of the mining activities. The mining activities left a lasting legacy of derelict mining infrastructure with negative effects on the surrounding environment and community, such as dormant mine shafts, sterilised land and abandoned Tailings Storage Facilities (TSFs). Due to lack of funds, commitment from mine owners and regulators these facilities are often left unrehabilitated, posing negative environmental impacts, including potential health hazards to the surrounding community. This legacy of problems posed by abandoned mines encountered in South Africa is probably unique in scale compared to any country in the world. A significant problem South Africa currently faces is an electricity shortage, especially during the high demand season from the start of June to end of August, when it is winter in South Africa. This period is occasionally associated with so called controlled “load shedding”, i.e. managed power interruptions to prevent overload and subsequent collapse of the electricity supply and distribution network. South Africa is highly reliant on coal-fired power stations for the majority of electricity consumed, which has detrimental effects on the environment due to high carbon emissions. However, a global shift towards renewable energy, as well as South Africa’s energy shortage, has forced the National Energy Regulator of South Africa to encourage greener alternatives. This study is aimed at finding an opportunity to generate more electricity, which is sustainable and with reduced carbon emissions. This study was conducted to determine the financial and practical feasibility of generating energy from the ERGO TSF, near Brakpan Johannesburg, as a post closure land use option. The following options were investigated: • Solar Photovoltaic electricity generation • Pump storage scheme development • A combinations of the above In addition, rainwater harvesting and wind power generation were also considered, but were abandoned early on in the study. From the study it was concluded that a Solar PV plant on top of the ERGO TSF will achieve the highest possible IRR of 10.70% and a power generation capacity of 471.9 MWp. Developing a pump storage scheme at the ERGO TSF can achieve an IRR of 10.27% and generation capacity of 78.2 MW. Combining the two options independently on the same site will result in an IRR of 10.61% and a combined peak generation capacity of 550 MW. If the combined system is required to be independent of the surplus electricity available in the grid an IRR of 10.32% and a combined generation capacity of 550 MW is achievable. From a financial and technical perspective it is considered to be most beneficial to implement only the solar PV plant on top of the ERGO TSF. Construction of a pump storage scheme on TSF is considered to be a challenging undertaking and seeing that its generation capacity is only 17% of that of the solar PV facility on the same ERGO site, it is probably not the optimal solution for utilisation. Solar panels are light weight structures that can easily be installed in large numbers on TSFs with little engineering challenges. / Dissertation (MEng)--University of Pretoria, 2015. / tm2015 / Civil Engineering / MEng / Unrestricted

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

Today mines produce metals which are used for everyday products by people worldwide. When metals are produced, waste products known as tailings are generated. These tailings are commonly stored in impoundments, surrounded by embankment dams. The demands from the society are constantly increasing regarding the quality and safety of dams. One step in development towards a better control regarding safety and quality of tailing dams, could be to compact the beach. Today there is a lack of methods to easy check the dry densities over large areas for a compacted material. Since these dams can be large structures with embankment lengths of several kilometers, it is necessary to be able to check the density with a fast method. In this thesis it was investigated if the dry density, and correspondingly the compaction, can be checked with a Dynamic Cone Penetrometer (DCP). In the thesis the dry density of tailings was compared with penetration rate of the DCP. A laboratory setup was made with a test box filled with tailings provided by Boliden AB from the Aitik mine. Six different box tests were performed, each test with different compaction. From the tests a trend was observed, for which the tailings increased in density as the DCP indexes showed an increased resistance. A relationship between DCP index and dry densities was found. Though a relationship was found, it is important to emphasize that the tests were carried out in an environment that was easy to control. One test with high water content showed that water was influencing the DCP index results. Therefore it was concluded that if the DCP will be used in field, the water content also has to be checked.

Tyrėjų duomenimis į javų kombaino valytuvo varpų sraigę patenka didelė dalis iškultų grūdų, kurie tiekiami į perkūlimo mechanizmą ir papildomai žalojami. Perkūlimui grąžinamų nuokulų kiekis ir sudėtis priklauso nuo javų kombaino konstrukcinių ir technologinių parametrų bei augalų savybių. Javų kombainuose naudojamos dvi pakartotinio kūlimo sistemos: nuokulos nukreipiamos pakartotinai kulti į kūlimo aparatą arba į varpų kultuvę. Dalis tyrėjų teigia, kad kombainuose su varpų kultuve grūdai yra žalojami mažiau. Tačiau kitų mokslininkų rezultatai byloja, kad vienas iš didžiausių varpų kultuvės trūkumų yra tas, kad joje ženkliai žalojami grūdai. Mokslininkų tyrimais nustatyta, kad tiekiamų į perkūlimo mechanizmą nuokulų sudėtis yra kombaino teisingo sureguliavimo viena pagrindinių rodiklių. Kombainu dirbant mažesniu nei optimalus greitis į varpų sraigę patenka daugiau iškultų grūdų, kurių sužalojimas yra didesnis. Šiame darbe gamybiniais bandymais nustatyta, kad padidinus kombaino darbinį greitį nuo 2 kmh-1 iki 5 kmh-1, tiekiama į varpų kultuvę kviečių nuokulų masė sumažėjo beveik du kartus. Grūdų sužalojimui įtakos turi ir varpų kultuvės rotoriaus sukimosi dažnis, kurio optimali skaitinė reikšmė yra 1300 min-1. Įvertinus atliktų laboratorinių tyrimų rezultatus galima teigti, kad javų kombaine varpų kultuvės rotoriaus dažnis galėtų būti reguliuojamas. Varpų kultuvės galios sąnaudos priklauso nuo tiekiamų nuokulų srauto. Padidinus nuokulų srautą į varpų kultuvę nuo 0,2 kgs-1 iki... [toliau žr. visą tekstą] / The volume and composition of the material in the tailings returns is directly responsive to the major combine settings, and dependent on the throughput and crop conditions. The research has shown that tailings returns frequently contain loose grain that does not need to be rethreshed. Loose grain in the tailings is more susceptible to damage when it is returned to an aggressive threshing cylinder or re-thresher. Published data other authors is showed some evidence that grain damage could be reduced with the use of an auxiliary tailings re-thresher instead of returning the tailings to the main threshing cylinder. The amount and composition of the tailings are strong indicators on how a combine is performing. Low throughput and its consequential grain damage can cause dramatic increases in combine losses. High levels of damaged grain in the tailings indicate excessive speed of rethreshing or inadequate throughput. The rational value of rotational speed of vane-type re-thresher of combine harvester is 1300 min-1 and it’s should be changeable. Power consumption was found to be dependent on rethresher throughput. When the feedrate is changes from 0.2 kgs-1 to 1.0 kgs-1, the power consumption for rethreshing of wheat increases from 1.53 kW to 2.44 kW.

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

When mining companies extract minerals from the earth, they leave huge deposits of soil and ore next to the mining site. These deposits are commonly known as tailings. In most instances, tailings contain a considerable amount of valuable mineral resources which cannot be exploited because of a lack of appropriate equipment, or as a result of economic non-viability. However, many mining companies choose to keep and maintain these tailings, in the hope that such minerals can later be exploited when time or technology allows for this. Under common-law the owner of a property is considered to also own any minerals contained on the property, in terms of the principle of cuius est solum. In South African law, however, a practice evolved whereby owners of minerals separated rights to minerals from the surface rights on the property. This created a mining right which was independent from the land and could be transferred to third parties, often in return for compensation. Under the Minerals Act of 1991 the owner of a mining right over a property (be that the owner of the property or a third-party mining right holder) also held the mining right to tailings which were created as a result of mining activities under the right. Thus, if a mining company performed mining activities on a property, the company was also free to exploit the tailings which were left next to its mine, regardless of whether the dump had remained there for a long period of time. Owing to South Africa's long history of mining, some tailings are over a century old and resemble small mountains rather than mining deposits. The Mineral and Petroleum Resources Development Act of 2002 changed the entire mineral legislative regime in South Africa. Whereas owners of land were previously free to separate and sell their rights to minerals to anyone they wished, the MPRDA placed the country‟s mineral and petroleum resources under the state's "custodianship." Where the law talks about custodianship, however, it supposedly refers only to minerals that have not yet been extracted from the earth. It is well established in South African law that, once a mineral is extracted, it becomes the movable property of the person who extracted it – in other words, that of the mining company. Does this mean that minerals in tailings also fall under the state's custodianship? The Free State High Court did not think so. In the case of De Beers v Ataqua it held that, in terms of the common law principles of acquisition by way of attachment, tailings are clearly movable property and therefore belong to the mining company who created them. For the MPRDA to hold otherwise would amount to expropriation. The state did not wish for some mining activities to be regulated by a different set of legislation, so it amended the MPRDA to try and define "residue deposits" (the name by which the MPRDA calls tailings) more clearly. However, due to the legislature's unfortunate choice of wording, tailings created before the enactment of the MPRDA are still, strictly speaking, not regulated by that Act. So the legislature proposed another amendment to the Act, this time making sure that any historical mine dump created at any point in South Africa's history are placed under the Act's regime. The subject matter of this study is whether the above amendments to the MPRDA could be considered to be expropriation. For background purposes, a brief overview of the Ataqua decision as well as the subsequent amendments to the MPRDA will be given. Then the history of mining legislation and the development of a separate mining right will be summarised. The reason for this summary is to establish whether, in terms of constitutional litigation, a clear right has been established for purposes of protection under section 25 of the Constitution. The last phase of the study will look at the particular characteristics of expropriation and ask the question whether acquisition of a right by the state is always a fundamental requirement for expropriation to take place. It is submitted that the destruction of an entire class of property by way of legislation, amounts to so-called "institutional expropriation," which is subject to compensation in terms of section 25. / LLM (Environmental Law and Governance), North-West University, Potchefstroom Campus, 2015

When mining companies extract minerals from the earth, they leave huge deposits of soil and ore next to the mining site. These deposits are commonly known as tailings. In most instances, tailings contain a considerable amount of valuable mineral resources which cannot be exploited because of a lack of appropriate equipment, or as a result of economic non-viability. However, many mining companies choose to keep and maintain these tailings, in the hope that such minerals can later be exploited when time or technology allows for this. Under common-law the owner of a property is considered to also own any minerals contained on the property, in terms of the principle of cuius est solum. In South African law, however, a practice evolved whereby owners of minerals separated rights to minerals from the surface rights on the property. This created a mining right which was independent from the land and could be transferred to third parties, often in return for compensation. Under the Minerals Act of 1991 the owner of a mining right over a property (be that the owner of the property or a third-party mining right holder) also held the mining right to tailings which were created as a result of mining activities under the right. Thus, if a mining company performed mining activities on a property, the company was also free to exploit the tailings which were left next to its mine, regardless of whether the dump had remained there for a long period of time. Owing to South Africa's long history of mining, some tailings are over a century old and resemble small mountains rather than mining deposits. The Mineral and Petroleum Resources Development Act of 2002 changed the entire mineral legislative regime in South Africa. Whereas owners of land were previously free to separate and sell their rights to minerals to anyone they wished, the MPRDA placed the country‟s mineral and petroleum resources under the state's "custodianship." Where the law talks about custodianship, however, it supposedly refers only to minerals that have not yet been extracted from the earth. It is well established in South African law that, once a mineral is extracted, it becomes the movable property of the person who extracted it – in other words, that of the mining company. Does this mean that minerals in tailings also fall under the state's custodianship? The Free State High Court did not think so. In the case of De Beers v Ataqua it held that, in terms of the common law principles of acquisition by way of attachment, tailings are clearly movable property and therefore belong to the mining company who created them. For the MPRDA to hold otherwise would amount to expropriation. The state did not wish for some mining activities to be regulated by a different set of legislation, so it amended the MPRDA to try and define "residue deposits" (the name by which the MPRDA calls tailings) more clearly. However, due to the legislature's unfortunate choice of wording, tailings created before the enactment of the MPRDA are still, strictly speaking, not regulated by that Act. So the legislature proposed another amendment to the Act, this time making sure that any historical mine dump created at any point in South Africa's history are placed under the Act's regime. The subject matter of this study is whether the above amendments to the MPRDA could be considered to be expropriation. For background purposes, a brief overview of the Ataqua decision as well as the subsequent amendments to the MPRDA will be given. Then the history of mining legislation and the development of a separate mining right will be summarised. The reason for this summary is to establish whether, in terms of constitutional litigation, a clear right has been established for purposes of protection under section 25 of the Constitution. The last phase of the study will look at the particular characteristics of expropriation and ask the question whether acquisition of a right by the state is always a fundamental requirement for expropriation to take place. It is submitted that the destruction of an entire class of property by way of legislation, amounts to so-called "institutional expropriation," which is subject to compensation in terms of section 25. / LLM (Environmental Law and Governance), North-West University, Potchefstroom Campus, 2015

No description available.