Orientador: Saul Barisnik Suslick / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-07-20T05:42:22Z (GMT). No. of bitstreams: 1 Moya_MauroMoreno_M.pdf: 4813473 bytes, checksum: a890c42d3a04945e8a6224adcb4286c2 (MD5) Previous issue date: 1995 / Resumo: As rochas ornamentais são utilizadas principalmente como material de revestimento na construção civil. Mundialmente a indústria é dominada pela Itália, que se utiliza de modernas e eficientes técnicas de beneficiamento destas rochas, e se caracteriza como um grande importador de blocos de rocha em estado bruto e exportador de produtos acabados. No Brasil, que entre as décadas de 70 e 80 se firmou como um grande exportador de blocos brutos, principalmente de granitos, entra na década de 90 com tendência à modernização do parque industrial para ocupar destaque dentre os exportadores de produtos manufaturados. Os principais produtores estão localizados nos Estados de Minas Gerais e Espírito Santo, com destaque também para a Bahia, Ceará, São Paulo e Rio de Janeiro. A produção de blocos atualmente esta ao redor de 580.000 m3. O consumo destas rochas no Brasil, atualmente em torno de 12 milhões de m2, ainda é pequeno quando comparado ao de outros países. A região de Bragança Paulista (SP) é reconhecida de longa data pela produção de rochas ornamentais, particularmente os granitos Vermelho Bragança e Preto Bragança. A extração destas rochas trouxe para a região a indústria de beneficiamento, que transformam o bloco bruto em chapas, sendo comercializadas no estado bruto ou polidas. Estão instaladas na área de estudo 06 empresas, cuja capacidade de beneficiamento chega a 420.000 m2 por ano com um faturamento estimado de US$ 9,44 milhões, gerando 267 empregos diretos. Em conjunto, estas empresas operam 24 áreas de lavra de granitos, espalhadas pelos Estados de Minas Gerais, Rio de Janeiro e São Paulo. Além da extração própria, estas empresas compram blocos de terceiros, beneficiando-os em sua unidade industrial / Abstract: Dimension stone are mainly used as cover material for construction industry. Italy is the leading producer of dimension stone, that use modero and efficient techniques to process these rocks. This country is also the biggest rough blocks importer and also a great exporter of manufactured products, like tiles and polished slabs. During the 70's and 80's Brazil became a big rough block exporter, mainly granites. In the 90's showed a trend for modemization of its industrial park which reflects in the increase of exports of manufactured products. The mainly producers are at Minas Gerais and Espírito Santo States, including Bahia, Ceará, São Paulo and Rio de Janeiro States. Presently the rough blocks production is approximately 580.000 m3. Consumption of this rocks at Brazil is approximately 12 million of square meters, which is small when compared with others industrial econormes. Bragança Paulista (SP) has been recognizing for long time for dimension stone sector, especially Vermelho Bragança and Preto Bragança Granites. The rock extraction brought to Bragança Paulista modemization of the quarrying and processing stone industries, that transform the rough block at slabs, which are sale polished or unpolished products. In the study area there is 6 companies, with processing capacity at 420.000 m2 per year and revenues of US$ 9,44 millions, generating directly 267 jobs. The firms operated 24 granites quarries, throughout Minas Gerais, Rio de Janeiro and São Paulo States. Besides their own extraction sites, the companies buy rough blocks for others sources and processing them at the industrial unit at Bragança Paulista / Mestrado / Administração e Politica de Recursos Minerais / Mestre em Geociências

Water resources management is high on the agenda both locally and globally because of its important role in social, economic and environmental development. For example, as part of the 2030 Agenda for Sustainable Development, all United Nations Member States adopted 17 Sustainable Development Goals (SDGs) in 2015 that covered thematic issues including water, energy, climate, oceans, urbanization, transport, science and technology. Sustainable Development Goal (SDG) no.6, which targets universal access to safe and affordable drinking water for all by 2030, is of particular interest in this study. The mining industry contributes to socio-economic development; however, it has also contributed to declining water quality in rivers and lakes in many regions globally. In this study, the status and governance of water resources within the Copperbelt province of Zambia over the period 2000 to 2020 was examined. The study investigated population and economic growth within the region and its correlation with changes in water quality and quantity. The research also focused on understanding the ways copper mining is affecting local water resources. The study also investigated challenges faced by regulators and institutions in the water sector, and considered how these challenges could be addressed. Secondary data was obtained from government institutions within Zambia such as National Water Supply and Sanitation Council (NWASCO), Water Resources Management Authority (WARMA) and Zambia Environmental Management Agency (ZEMA), which are the key institutions in the water sector and the environment. Semi-structured interviews were also conducted with the three key institutions in the water and pollution control sectors. The results showed that the total population in the Copperbelt province has increased by 20% since 2000 to a total of 1 972 317 in 2010. The population is projected to be 2 669 635 in 2020, representing about 27% increase from 2010. The rural population is projected to be 423 511 in 2020, representing about 11% increase from 2010 while the urban population will be 2 246 124 in 2020 representing about 29% increase from 2010. The majority of this growth has occurred in urban areas, which grew by about 30% from 2000 to a total of 1 595 456 in 2010. Rural population has increased by 8% since 2000 to a total of 376 861. The results also showed increased economic activities driven mainly by copper mining. Water abstraction has generally declined since 2000 mainly due to decrease in mining activities. In 2000, about 1 million m3 /day was abstracted in the Copperbelt province and about 600 000 m3 per day in 2005. The reduction in 2005 could be attributed to reduction in mining activities and institutional changes in the water sector. Water production and consumption from commercial utilities has generally been in decline from 2000 to 2017. This is also the case with water consumption per capita and water production per capita. For example, water consumption per capita per day in 2001 was 203 liters and reduced to 113 liters in 2017, representing a 44% reduction in consumption. The results showed that water consumption from 2004 to 2008 averaged 100 million m3 while the production averaged 160 million m3 per year. NWASCO attributed the general downward trend in water production and consumption in the province to maintenance and rehabilitation of water infrastructure, and investment in new infrastructure, thereby reducing the unaccounted-for water. The other reason could be that new housing developments prefer to use groundwater sources rather than utility water (supplied by water companies). The reduction could also be attributed to the cost of water and that consumers needed to adjust from the background where utility services such as water supply and sanitation were the sole responsibilities of the mines (ZCCM), prior to privatization. In terms of water supply and sanitation coverage, there has been an increased coverage since 2000. In 2001, the population that had access to water supply and sanitation was 81% and 46%, respectively. Therefore, roughly 50% of the population had no access to sanitation. However, in 2017 the population with access to water supply and sanitation was 91% and 75%, respectively. This represented only 25% of the population in serviced areas that had no access to sanitation. Between 2007 and 2008, the sanitation coverage had seen a reduction compared to the year 2006. This was due to institutional changes on the Copperbelt province, and the 2008 economic recession – the mine townships that were previously serviced by an asset holding after privatization of the mines were taken over by other utility companies. Consequently, the service delivery in the province initially dropped, but then started increasing again in 2009.

Gold mining generates large quantities of tailings waste. These tailings can have a significant negative impact on the surrounding environment, with concomitant effects on local ecosystems, as well as on human health and quality of livelihoods. The latter is a concern in the Witwatersrand goldfields of South Africa, where communities are located in close proximity to gold mining operations and/or both current and defunct tailings dumps. This research project was, therefore, aimed at developing a better understanding of the facts, perceptions, concerns, and expectations associated with Witwatersrand gold mine tailings storage facilities, and how these are related. In order to fulfil this aim, a desktop study was conducted which involved a detailed review of published academic literature, company reports, newspaper articles, gold mining magazines, and specialist reports with specific emphasis placed on the Central Rand goldfields of the Witwatersrand Basin. Semi-structured interviews were also conducted with representatives from the community, civil society organisations and independent experts, using the defunct Princess gold tailings dump in Davidsonville Suburb (West of Johannesburg) as a case study. The literature review of the study has shown that there is environmental pollution (air, water and soil) due to gold tailings dumps in current and historic gold mining areas. These findings were found to be largely consistent with perceptions and concerns of the community members, civil society organisations and subject matter experts. The long-term impacts of this pollution are not only environmental but cause a huge social burden on health and quality of livelihoods. Not only is dust considered a nuisance, particularly in the windy season, but the dust has been proven to contain crystalline silica and radionuclides. The long-term exposure to this dust can lead to skin problems and respiratory illnesses. There is higher exposure of ambient particulate matter (PM10) in areas around tailings even at distances up to 2 km downwind from the tailings dumps. Acid mine drainage, on the other hand, increases metal load in watercourses and soils, ultimately affecting the ecosystems as the metals are toxic to plants. Metal contamination has adverse impacts on animal and human health. In addition to literature survey, results from the semi-structured interviews revealed that there are conflicts between the communities, government and mining companies, with communities associating their health problems with gold mine tailings. This has led to court cases and gained media attention. The complex relationships between mine waste, the environment, and community health and livelihoods are still not well understood, making it difficult to justify and motivate the implementation of meaningful interventions to mitigate risks associated with gold tailings dumps. To date, little attempt appears to have been made to support community concerns and perceptions with factual evidence and information. Overall, this study has demonstrated the existence of longstanding issues associated with defunct gold tailings dumps and the communication gab that existing between various stakeholders, i.e. community, government and mining houses. These emphases the importance of having adequate remedial actions to prevent further pollution, the need to engage all relevant stakeholders when dealing with gold tailings and implementation of regulatory frameworks associated with gold tailings reclamation and rehabilitation.

The recent discoveries of natural gas in Tanzania, estimated at about fifty-seven trillion cubic feet (tcf), have sparked tremendous hopes for socio-economic development in the country. While this optimism seems to be supported by conventional wisdom and economic insights, evidence from other oil-rich African countries shows that in spite of the ongoing oil and gas extraction, they are floundering in poverty, corruption and political instability. This phenomenal dichotomy between oil and gas wealth and socioeconomic development is referred to as the "resource curse". As this study demonstrates, the "curse" is partly a result of under-taxation. This study uses the resource curse study to analyze and evaluate tax-related challenges in the Tanzanian upstream oil and gas industry. In doing so, the study identifies three factors that may cause loss of potential tax revenues - referred to as "tax revenue leakage". First, the discretionary tax incentives, such as tax exemptions, lowering tax rates and special tax treatment, result in non-payment of taxes that would have otherwise been payable. Second, the International Oil Companies (IOCs) adopt a variety of techniques, such as transfer pricing, thin capitalization, corporate re-organization tax evasion and treaty shopping to exploit the loopholes or gaps in the tax laws to minimize, reduce or eliminate their tax obligations without being detected or punished. Third, corrupt Government officials willfully fail to collect taxes due, short levy taxes, grant undeserving tax incentives to the IOCs or divert revenues collected for their own account. All these factors demonstrate the close connection between under-taxation, corruption and tax avoidance. As this study argues, in the absence of counteractive measures, the Government will collect only a fraction of potential taxes, thus losing revenues required to finance development projects. The study establishes that Tanzania counteracts tax avoidance and tax evasion through anti-avoidance legislation. Tanzania also has accountability measures, which impose restraints on the exercise of public power and prevent corruption. The study concludes that although Tanzania has a competitive fiscal regime, anti-avoidance legislation and systems of accountability, the level of Government's tax revenue nevertheless depends on institutional capacity to detect, prevent and penalize tax avoidance schemes and corruption.

Mining, by its nature, provides enormous investment to the mining nations and by extension contributes to the socio-economic development of the host communities. Where these communities exist, they remain a cause of concern since they are predominantly dependent on the economic opportunities generated by the mine. The Environmental Impact Assessment (EIA) functions in mining are somewhat of a risk reduction activity, even though the potential of halting projects is comparatively rare in situations where proposals are deemed to be of national interest and politically significant. This study highlights the environmental and socio-economic impact of lack of land use planning in host communities where the phenomenon of mine closure is a lived reality and evaluates alternative post-mining land use. In this study a case study, qualitative research approach is used to comparatively evaluate three mining EIA reports (EIA on the extension of mining operations at the Vlakvarkfontein Coal Mine; consolidation of high extraction mining impacts in the Trichardtsfontein; and rail loop, road diversion and pipeline project associated with Temo Coal) on the extent of post-mine land use consideration in the EIA process. Furthermore, the study, inter alia, assessed the extent to which the interested and affected parties' input was considered in EIA reports. In rehabilitation, the applicant is only reinstating the area, as closely as possible, to that which existed pre-mining, and should not be confused as post-mining land use. There is nothing new in providing for rehabilitation in EIA – it is a standard practice. However, the mining EIA reports extensively covered the environmental components, particularly the specialist studies, as they assessed whether projects conformed with the regulatory requirements. The emphasis of the mining EIA reports was mainly on the environmental component with – other than employment and economic benefits – no post-mining land use and socio-economic impact indicators. These trends were found to be further reinforced when the input of the interested and affected parties (I&APs) was analysed. In view of the findings of this study, the main recommendations to improve the EIA systems would be to clarify and simplify the mandates of the several institutions involved in the EIA process and system; and to improve and increase public access to EIA reports, including electronic means. This is pertinent due to the conspicuous absence of EIA reports in the public domain, which contributed to the limited number of EIA reports that were reviewed in this dissertation. In addition, public participation processes (PPP) should be conducted in most common languages of the stakeholders; and specialist social impact assessment should go beyond the traditional socio-economic issues faced by I&APs to include post-mining land use, as well as sustainable post-mining economy.

Coal dust is inextricably linked to the development of dust diseases. To date, the role of mineral matter in coal has been investigated for its links to pulmonary damage; however, no consensus has been reached on which characteristics are relevant to pulmonary toxicity. This study hypothesises that the toxic potential of inhalable coal dust can be attributed to reactive mineralogy and the specific surface area for interaction between the particles and primary phagocytes such as macrophages. To test this hypothesis, the study developed an advanced understanding of the relationship between the physicochemical and mineralogical characteristics of coal particles and pulmonary toxicity. Three objectives were constructed to achieve this aim. Objective 1 developed a detailed particle characterisation dataset on coal particle samples utilising both routine (X-ray diffraction and X-ray fluorescence) and advanced methods of coal analysis (automated scanning electron microscopy systems). Objective 2 elucidated multivariant relationships between the particle characteristics and the immunological responses from exposed macrophage cells in vitro using advanced statistical methods. Lastly, objective 3 developed a protocol to empirically characterise the relative risk of coal dust-related damage on a cellular level. In developing a detailed characterisation dataset on the coal samples, both routine and automated analysis tools were used to define general, chemical, mineralogical, and mineral specific characteristics. An auto-SEM-EDS-XRD (Automated scanning electron microscope coupled with Energy Dispersive X-ray Spectroscopy and analyses generated by X-ray Diffraction) protocol was developed to obtain a broad spectrum of particle data by mineralogically mapping each particle. This protocol involved the rigorous analysis of uncertainty in the data using comparative datasets generated from XRD and XRF (X-ray Fluorescence) analyses. In summary, the study demonstrated that the combined use of both routine and advanced particle analysis tools allowed for the classification of chemical and mineralogical distributions as well as a discrimination between general and mineral specific particle characteristics. Generally, these results suggested that features relating to general particle characteristics (size, shape, roughness, and surface area) are more strongly a function of mechanical breakage and deformation than compositional variation. To assess the multivariant relationships between the numerous characteristics defined and response measures of cellular toxicity, a PLSR (partial least squares regression) was applied in a novel approach to attempt a single model comparison of such relationships. This model was chosen for its ability to relate response and explanatory variables based on a new set of variables which have undergone dimensionality reduction whilst maximising the covariance. The results from the relationship analysis showed that physical characteristics (particle shape in particular) displayed a greater influence on cytotoxicity and lipid peroxidation over mineral and chemical-based characteristics. Relating this observation to previous research it was suggested that the influence of shape and roughness on phagocytosis may have strong implications for magnitude of direct and indirect cellular harm and the predominance of either intracellular or extracellular damage. The results also showed that, apart from the influence of particle shape, radical-induced stress and cytotoxicity displayed a strong dependency on (1) the chemical and mineralogical reactivity Ca hosted in gypsum, (2) the release/inhibition of Fe from pyrite and Fe-sulfates, and (3) the surface activity of quartz based on its crystallite size. However, the relationships defined in the context of cytotoxicity displayed a more nuanced dependency with the silicate mineral content and their associated properties compared to lipid peroxidation. From this it was suggested that non-radical related pathways to cytotoxicity could also occur from coal dust exposure. Ultimately, the study demonstrates the first analysis which assesses relative impact and magnitude of multiple particle characteristics on cytotoxicity and cellular stress. Finally, to provide a more easily interpretable format for the analysis of the PLSR relationships, a protocol was developed to screen variables based on: (1) their level of importance to the defined relationship and (2) the rank of importance for each influential variable represented on a unified scale. Elements which explained the variability within the sample characteristics and the responses were clustered using the k-means algorithm to determine classes of samples which display similar characteristics or levels of toxicity. The comparison of the classes grouping samples with similar properties versus samples groups with similar toxicity levels showed that even though samples may share similar properties, their reported level of toxicity may differ. This confirms the observations from previous studies which have shown that the relative toxicity of coal dust cannot be explained on the basis of isolated properties. Rather the set of ‘influential variables' showed that a combination of general, chemical, mineralogical and mineral specific data are needed to determine the differences between levels of toxicity. Ultimately, the application of this protocol on 17 different dust-sized coal samples demonstrated the key differences between samples and their influence on levels of cytotoxicity and lipid peroxidation, which until this study have not been demonstrated by a single regression. As an outcome of such results, this study provides a robust analysis strategy for elucidating particle cell relations which can further advance the understanding of coal dust induced disease pathology. Additionally, the protocol has demonstrated the usefulness of disseminating the complex data structures to more easily interpretable data formats such that a generalisable analysis of risk factors related to coal dust-based cellular damage can be utilised by stakeholders in data-based decision making. Ultimately, the results of this study propose that the toxic potential of coal dust is primarily a function of the reactive mineralogical and chemical components within the particles, however, the magnitude of this intrinsic reactivity is subject to the mitigative factors which can either neutralise of supress the anticipated reactivity.

The mining industry has remained Zambia's dominant industry for almost a century. According to the report by International Council for Mines and Minerals (ICMM) for 2013, Zambia is highly dependent on copper mining as the core productive industry. Mining contributes to direct employment (approximately at 1.7%), foreign direct investment (approximately at 86%), gross domestic product (more than 12%) and government revenue (more than 25%). Regardless of these economical enactments, the accident frequency across the mines is very significant. In general, the mining industry is perceived to be a high-risk industry. The increase in the number of mining accidents is extremely costly, whether measured in terms of medical expenses and disability compensation, loss of production and wages or damage to plant and equipment. The human cost, in terms of death and suffering, is beyond calculation. In recent years, there has been some innovations in terms of technology regarding mining methods, and this has resulted in decreased accident occurrence in the mines. The human factors involved in the mine accidents need to be addressed further to reduce these rates. Therefore, the best approach is first to understand mine accident causality, and then this will be a foremost step in a pursuit to diminish the high rate of accidents. Effective remedies and measures can be designed if only accident process is properly understood. The understanding and interpretation of causes of accidents at workplaces can only be achieved by accident modelling techniques. The effective way of analysing industrial accidents has been proven by the Swiss Cheese Model, which is also applicable to this study. The Swiss Cheese Model describes an accident as an event which happen within organization due to the combination of different unsafe acts which may include latent conditions and front-line operators. The purpose of this study was to determine how systemic factors contribute to accidents at a copper mining company in Zambia. The analysed results were compared with those of other local mines as well as mines from developed and developing countries. The approach in this study involves using the existing framework developed by Bonsu (2013). The framework had used the concepts from the Mark III of the Swiss Cheese Model, Incident Cause Analysis, safety management principles and the Nertney Wheel. The sections involved in the existing framework of Bonsu (2013) are metadata, accident barrier analysis and causal analysis. The accident causality section is designed and described in the same way as the Mark III version of the SCM. This section is used for analysis of accident causality and is categorized into proximal, work place and systemic factors. The metadata section offers explanations on different factors that influence the happening of accidents at this copper mining company in Zambia. Metadata section captures the information on accidents analysed under the barriers and causing agency section of the framework. The variables under the metadata are time and date of accident, place of the accident, accident type, activity involved which resulted in the accidents, task schedule of the accidents, age of the victim, experience of the victim, job status, etc. The last section of the existing framework is the agency and barrier analysis and was designed by Bonsu (2013) to capture data on the safety barriers which were breached and accident causing agents in the accident report. The accident reports collected from the copper mining company in Zambia were used in the existing framework and the analysed results were presented as unsafe acts, workplace and systemic factors with linkages to each other. The most prominent type of unsafe acts recognized were routine violation (recognized in 38% of all the accident analysed), closely followed by slips and lapses (identified in 30%) and then mistakes (21%). Exceptional violation and non-human cause were the lowest at 9% and 2% respectively. Systemic and workplace factors were involved in 78.2% of the accident reports that were analysed. The most prominent workplace factor recognized was behavioural environment (25.8% of all cases analysed), closely followed by physical environment (23.4% of all cases analysed), then unsafe work practices (18.8% of the accidents analysed), then fit-for purpose equipment (16.4% of the accidents analysed) and finally competent people (15.6% of the accidents analysed). In general, under the category of accident analysis on workplace factors, all the five factors were significantly contributing to the causes of accidents at the mine site that was investigated as demonstrated by the closeness in percentages. In the case of systemic factors, inadequate supervision or leadership was the most prominent factor identified (22.6% in all accidents analysed). It was also found that physical environment (23.4% of all cases considered) was the second most dominant workplace factor recognized. The results obtained also revealed that some systemic factors were associated with specific workplace factors more than others. For instance, the result of behavioural environment (workplace factor) was usually due to poor leadership problem (systemic factor), problems seen in housekeeping (systemic factor), hazard identification (systemic factor), risk management (systemic factor), and designs (systemic factor), these were also the causes of poor physical environment. In the unsafe work practices (workplace factor), hazard identification was the most common systemic factor that was recognized whereas in fit for purpose equipment (workplace factor) the most common associated systemic factors were risk management, leadership, hazard identification and design. The results obtained in this study were compared to those obtained in the study of Mwansa (2021), which also applied the framework used in this study to the analysis of accident reports from another mine site of the same mining company in Zambia as used in this study. Similarities and differences were obtained under the accident characterization and causation sections. The operations in both studies are different in terms of mining methods and metallurgical processing plants. This may be responsible for some of the differences in the results obtained in both studies. For instance, in Mwansa's (2021) study, the most dominant unsafe act recognized was also routine violation (36% of all cases considered) whereas the most prominent workplace factors recognized were physical environment (36% of all cases considered) and unsafe work practices (27% of all cases considered). In Mwansa's (2021) study, the most prominent systemic factors recognized as contributing to physical environment were hazard identification, work schedule, risk management, maintenance management, leadership, housekeeping, and contractor management. The results obtained in this study were also compared with previous studies from different commodities across the globe. This was done to have broader picture when dealing with mine accidents. The causes of accidents identified in this study are of significance to the safety of the industry. Overall, based on the analysis carried out in this study for the copper mining site investigated, it can be concluded that systemic factors are the main causes of accidents rather than human error and violations.

Water is a vital transport and process medium used in mineral processing. Fresh water is substantially utilized as an ideal flotation media in the froth flotation process (Rao et al., 2016). However, the mining sector is impelled to save on the consumption of fresh water and reduce waste discharge owing to limited freshwater supply (Ridoutt and Pfister, 2010), stringent environmental regulations (Amezaga et al., 2011) and the increase in water demand among multiple users (Rijsberman, 2006). To improve water efficiency, the use of impure primary water supplies, and process water recycling has been implemented in flotation circuits. Generally, the recycling of process water is executed from tailings dams, thickener overflows, and dewatering and filtration units. The recycling of process water has been considered to be advantageous as it reduces freshwater consumption, lowers waste discharge and reduces volumes of reagents required in flotation circuits (Muzenda, 2010). However, recycled process water has been found to exhibit increased concentrations of typical contaminants such as colloidal matter, metal ions, sulphates, sulphites, thiosalts, calcium, magnesium, sodium, potassium, and residual floatation reagents. These contaminants affect the process water quality, which plays a vital role in flotation efficiency. Though a significant amount of work has been done on the effects of water quality on the flotation of valuable minerals, many studies have focussed on base metal sulphides and the use of benchscale techniques. Literature speculates that ions in process water hinder the interaction between xanthate collectors and valuable minerals, hence, contributing to a decrease in flotation recoveries (Kirjavainen et al., 2002, Boujounoui et al., 2015). The findings in literature have been deduced without an understanding of the underlying mechanisms of interaction between xanthate collectors and mineral surfaces in the presence of ions. Accordingly, literature still holds a lack of understanding on how ions affect the adsorption of xanthate collectors on mineral surfaces. This study, therefore, seeks to unpack the underlying mechanisms of interfacial interactions between ions with PGMs and the subsequent adsorption kinetics of a xanthate collector. This study investigated the effects of Ca2+, Mg2+, SO4 2- , S2O3 2- and Na+ ions at increasing ionic strength, on the adsorption of SIBX on synthetic PdS and PdTe2 minerals. The selection of the minerals was based on the need to give an insight into the differences in reactivities of the very floatable minerals (PdS) and the difficult-to-float minerals (PdTe2), with SIBX in the presence of ions. The mechanisms in question were examined by electrochemical techniques at laboratory scale. Rest potential measurements were used to determine the interactions of ions and/or SIBX on the PGM surfaces. Cyclic voltammetry was employed to determine the redox reactions that occur on the PGM surfaces in the absence and presence of ions and SIBX. Ultimately, electrochemical impedance spectroscopy was used to demonstrate the adsorption mechanisms of SIBX in the absence and presence of the investigated ions. The rest potential measurements generally displayed an increase in the extent of interactions between the investigated ions with the palladium minerals, with an increase in ionic strength. An inverse relationship was exhibited on the extent of interactions between the ions and PdS, and the extent of interaction between SIBX and PdS. Divalent ions displayed higher interactions with the palladium minerals than the monovalent ions investigated. All salts were found to demonstrate a decrease in the rest potential for PdS at all concentrations except for MgSO4, which increased the rest potential at 5 SPW and 10 SPW. Final rest potentials for most conditions were observed to be above the equilibrium potential of dixanthogen formation except for Na2S2O3 at 3 SPW, 5 SPW and 10 SPW, and CaCl2 at 1 SPW. Dixanthogen formation was most likely favoured on PdS for the conditions with final rest potentials above the equilibrium potential of dixanthogen formation. With regard to the PdTe2 mineral, it was found that most ions enhanced the interaction between SIBX and PdTe2. Contrary to the findings of PdS, it was found that most salts exhibited an increase in rest potential on PdTe2 except for Na2S2O3. Final rest potentials for all conditions investigated were observed to occur above the equilibrium potential of dixanthogen formation except for Na2S2O3 at all ionic strengths, MgCl2 at 10 SPW and NaCl at ionic strengths of 3 SPW, 5 SPW and 10 SPW. The latter conditions show that the formation of a metal-xanthate on PdTe2 was favoured. Generally, for both minerals, NaCl displayed the least interaction. It was found that increasing the ionic strength of salts, generally decreased the rate of dixanthogen formation on PdS. On the contrary, SIBX interacted more with PdTe2 at an increase in the ionic strength of salts. This observation favoured the formation of either a metal-xanthate or dixanthogen at a slower rate. Additionally, it was determined that the adsorption of ions investigated occurred via interfacial charge transfer kinetics, where an ion exchange mechanism has been proposed in the case of the divalent anions. In the case of divalent cations, it was presumed that the ions dissociate in solution and precipitate upon their interaction with the palladium minerals to hydroxides and/or carbonates. This study has shown that the mechanism of adsorption of ions on palladium minerals is heavily influenced by the type of mineral surface onto which the ions adsorb. The extent of interaction of ions with palladium minerals together with their corresponding oxidation products can be determined by the mineral type and the salt type and its ionic strength. Moreover, it was denoted that an electrochemical system that consists of salts at the palladium mineral surfaces can best be described by a resistor, Rs in series with a parallel circuit of a capacitor, Cdl, representing the electrical double layer and a resistor indicating Rct. For an electrochemical system with both salt and SIBX, it has been surmised that an equivalent circuit consisting of a resistor, Rs, in series with a parallel circuit of a capacitor, Cc, representing a coating layer formed on the palladium surfaces as a result of the adsorption and oxidation od SIBX and a capacitor, Cdl. This work has shown that the mechanisms of interactions between xanthates and PGMs in the absence and presence of salts can be successfully determined using electrochemical techniques. An understanding of such mechanisms developed from the interactions of Ca2+, Mg2+, SO4 2- , S2O3 2- and Na+ ions with SIBX on PGM minerals will help alleviate flotation problems caused by the troublesome ions. An understanding of the mechanisms proposed by this study will act as a diagnostic tool for developing flotation strategies that will maximize flotation recoveries where water quality is concerned

The mineral nutrient storage reserves in various parts of white spruce (Picea glauca) seeds and somatic embryos were investigated. Somatic embryos are produced in tissue culture from single cells or small groups of cells. These cells are induced to produce a callus, which is then stimulated to produce mature somatic embryos that are desiccated down to moisture content levels comparable to those of a mature dry seed. Morphological comparisons revealed that somatic and zygotic embryos are very similar. Somatic embryos of white spruce; however, were larger, had a flared arrangement of cotyledons, had more prominent suspensor regions, had intercellular spaces in the ground meristem tissue and had ground meristem cells that had divided in several planes of division. Using a wet ashing protocol, anion exchange resins and the molybdenum blue colourimetric reaction, the total levels of P and the amount of P bound to phytic acid were measured. Phytic acid (or phytate) is the major nutrient storage compound in seeds. Although differences were found on a dry weight basis, a single somatic and a single zygotic embryo had similar levels of P. Somatic embryos produced in different batches varied in their levels of phytic acid, but a somatic embryo could have similar levels of phytic acid as a zygotic embryo. The large female gametophyte contained 86% of the total P and 95% of the total phytic acid in a single seed. Electron microscopy and energy dispersive x-ray analysis found phytate-rich globoids in the procambium and ground meristem tissues of both types of embryos. Globoids contained high P, moderate K and Mg, and little if any Ca, Fe and Zn. Globoids were generally larger and more frequent in zygotic embryos. Globoids from the cotyledon procambium of zygotic embryos also contained moderate levels of Fe. Iron-rich particles (possible Fe-phytate deposits) were found in the protoderm, procambium and ground meristem of both types of embryos. These deposits contained high P and Fe, moderate K and Mg, and little if any Ca and Zn. Globoid and Fe-rich particle compositions were similar in both embryo types, but significantly higher Fe:P ratios were found in zygotic embryos. Atomic absorption spectroscopy was used to measure total K, Mg, Ca, Fe and Zn levels. Although differences were found on a dry weight basis, a single white spruce somatic or zygotic embryo contained similar levels of all these elements. The female gametophyte contained high levels of these elements and the seed coat contained considerable Ca. Potassium leakage during imbibition in germination medium revealed that a single somatic and zygotic embryo of white spruce leaked similar levels of K. Pretreatment of somatic embryos in a high relative humidity environment resulted in decreased potassium leakage by 80 and 120 min. of imbibition. The seed coat was found to reduce the amounts of K leaked. Surface cells in dry somatic and zygotic embryos were found to be wrinkled, but cells in zygotic embryos were more shrunken in appearance. During imbibition, cells became more turgid; but after 120 min. of imbibition, surface cells still showed signs of wrinkling. To date, this is the first major report of mineral nutrition in white spruce seeds and is the first comprehensive comparison of mineral nutrients in white spruce seeds and somatic embryos. These results may be useful in producing complete artificial white spruce seeds. / Thesis / Master of Science (MS)

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