This research is on mines that struggle to obtain closure from the state departments. The closure process at the footprints of five Tailings Storage Facilities (TSFs) of a South African gold mine was investigated. They are situated in the Germiston, Brakpan, Springs and Nigel suburbs of the East Rand region of Johannesburg. Very limited scientific research has been done in South Africa on the management of mine closure. The most recent performed research was completed at Coal mines and only one was at an underground gold mine. The history of the case studies at a surface gold mine revealed similar problems, as confirmed in previous research, during the interviews with mine management and the review of operational documents. There is a whole array of causes giving rise to the struggle to obtain closure by a mine, that will be subsequently discussed. Major causes are the lack of estimation of closure costs and the lack of a proper Project Life Cycle (PLC) process for closure by mine management. Previous investigations indicated a general shortfall in estimated closure costs, mining operations that are not planned with closure in mind, closure objectives that are not set at all management levels, final land use after mine closure that is not defined properly, residual and latent impacts that are not dealt with, the post-closure period when the final impact will occur that is not defined and a proper risk assessment based on detailed information that is not properly done and communicated. Another cause is that the integrated process of making closure part of the Environmental Management Programme Report (EMPR) process is not followed. The result of not following the correct process is that mines do not obtain closure. Another reason why mines do not obtain closure is because of an underdeveloped mine infrastructure, e.g. tailings facilities, waste rock dumps, shafts and plants that are not constructed in an environmentally friendly way during the operational phases to facilitate closure. Therefore, these structures need to be changed in terms of their topography and growth medium to ensure an improvement in environmental parameters. This will assist in obtaining sustainability and final closure. Significantly more trust fund money than initially estimated during operations needs to be spent to ensure the above change. Specific issues defined from the case studies were the adaptation of the administration of the closure process, the management of risks, especially the differences in opinions, the management of the mine life cycle for closure and involvement of the land owners and Interested and Affected Parties (l&APs). This research was necessary because companies are uncertain and lack the competency to estimate and to correctly spend trust fund money in order to be sure of obtaining closure. This situation threatens the long-term survival of mining-companies by holding assets and profits back until closure is attained. The state departments also have to address the risks and have to rehabilitate the polluted mine sites if companies do not obtain closure. A proper PLC to facilitate closure was compiled from the above-mentioned data. An important fact to bear in mind is that the activities within the life cycle depend on one another. Therefore, when one activity is disregarded or not properly performed, it will influence the outcome of the remaining activities. The methodology of the research was as follows: Categories to evaluate the closure process of the selected case studies were determined from the project life cycle and the management principles of the literature review. Thereafter a questionnaire was developed from these categories. The questionnaire was subsequently used to guide interviews. After the interviews these categories and findings from the questionnaire were combined and summarised into key findings. The key findings of the research were: • The driving force behind obtaining closure must shift from the State Departments to the mining companies. They must realise there is an opportunity during the closure process to make money and to minimise their long-term liability. The mining company must thus drive the closure process to obtain environmental sustainability. • The gold mines do have problems in terms of cost estimation and trust fund expenditure at their TSF footprints during the closure process. The reasons were a mismanagement of the closure process and making use of a limited information system to make decisions. • A proper closure process does exist, but it can be improved to ensure all interested and affected parties have the same expectations from closure. • There are many activities in the closure process flow diagram which were not properly attended to according to the case studies. • A conceptual closure plan and a draft rehabilitation plan with broad objectives, policies and strategies with detailed descriptions were not compiled during the operational phase, because limited scientific monitoring information was gathered to do a proper risk assessment and some l&APs consultation was done mainly with the material and land owners on a one on one basis. From these key findings the following recommendations could be formulated: • Any mining operation should conduct a closure audit at least every second year and before mining activities change. • A searchable record keeping system must be established to keep track of the closure life cycle development. • Detailed conceptual and final closure plans need to capture the data from the audits and record keeping system. • A communication forum with company management and environmental specialists needs to be established. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2009.

This research is on mines that struggle to obtain closure from the state departments. The closure process at the footprints of five Tailings Storage Facilities (TSFs) of a South African gold mine was investigated. They are situated in the Germiston, Brakpan, Springs and Nigel suburbs of the East Rand region of Johannesburg. Very limited scientific research has been done in South Africa on the management of mine closure. The most recent performed research was completed at Coal mines and only one was at an underground gold mine. The history of the case studies at a surface gold mine revealed similar problems, as confirmed in previous research, during the interviews with mine management and the review of operational documents. There is a whole array of causes giving rise to the struggle to obtain closure by a mine, that will be subsequently discussed. Major causes are the lack of estimation of closure costs and the lack of a proper Project Life Cycle (PLC) process for closure by mine management. Previous investigations indicated a general shortfall in estimated closure costs, mining operations that are not planned with closure in mind, closure objectives that are not set at all management levels, final land use after mine closure that is not defined properly, residual and latent impacts that are not dealt with, the post-closure period when the final impact will occur that is not defined and a proper risk assessment based on detailed information that is not properly done and communicated. Another cause is that the integrated process of making closure part of the Environmental Management Programme Report (EMPR) process is not followed. The result of not following the correct process is that mines do not obtain closure. Another reason why mines do not obtain closure is because of an underdeveloped mine infrastructure, e.g. tailings facilities, waste rock dumps, shafts and plants that are not constructed in an environmentally friendly way during the operational phases to facilitate closure. Therefore, these structures need to be changed in terms of their topography and growth medium to ensure an improvement in environmental parameters. This will assist in obtaining sustainability and final closure. Significantly more trust fund money than initially estimated during operations needs to be spent to ensure the above change. Specific issues defined from the case studies were the adaptation of the administration of the closure process, the management of risks, especially the differences in opinions, the management of the mine life cycle for closure and involvement of the land owners and Interested and Affected Parties (l&APs). This research was necessary because companies are uncertain and lack the competency to estimate and to correctly spend trust fund money in order to be sure of obtaining closure. This situation threatens the long-term survival of mining-companies by holding assets and profits back until closure is attained. The state departments also have to address the risks and have to rehabilitate the polluted mine sites if companies do not obtain closure. A proper PLC to facilitate closure was compiled from the above-mentioned data. An important fact to bear in mind is that the activities within the life cycle depend on one another. Therefore, when one activity is disregarded or not properly performed, it will influence the outcome of the remaining activities. The methodology of the research was as follows: Categories to evaluate the closure process of the selected case studies were determined from the project life cycle and the management principles of the literature review. Thereafter a questionnaire was developed from these categories. The questionnaire was subsequently used to guide interviews. After the interviews these categories and findings from the questionnaire were combined and summarised into key findings. The key findings of the research were: • The driving force behind obtaining closure must shift from the State Departments to the mining companies. They must realise there is an opportunity during the closure process to make money and to minimise their long-term liability. The mining company must thus drive the closure process to obtain environmental sustainability. • The gold mines do have problems in terms of cost estimation and trust fund expenditure at their TSF footprints during the closure process. The reasons were a mismanagement of the closure process and making use of a limited information system to make decisions. • A proper closure process does exist, but it can be improved to ensure all interested and affected parties have the same expectations from closure. • There are many activities in the closure process flow diagram which were not properly attended to according to the case studies. • A conceptual closure plan and a draft rehabilitation plan with broad objectives, policies and strategies with detailed descriptions were not compiled during the operational phase, because limited scientific monitoring information was gathered to do a proper risk assessment and some l&APs consultation was done mainly with the material and land owners on a one on one basis. From these key findings the following recommendations could be formulated: • Any mining operation should conduct a closure audit at least every second year and before mining activities change. • A searchable record keeping system must be established to keep track of the closure life cycle development. • Detailed conceptual and final closure plans need to capture the data from the audits and record keeping system. • A communication forum with company management and environmental specialists needs to be established. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2009.

Includes bibliographical references / xii, [291] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil Engineering, 1992

Nuclear energy can be used to reliably generate large quantities of electricity while providing minimal lifetime CO2 emissions. Given the extreme importance of safety in the nuclear industry, it is necessary to have a fundamental understanding of the materials used throughout the nuclear fuel cycle. It is of particular to importance to develop an understanding of these materials at an atomic level. In this thesis, X-ray absorption spectroscopy (XAS), along with several other X-ray based techniques, has been used to study materials that are produced or proposed for use in the nuclear fuel cycle. Uranium mining and milling operations generate large quantities of waste, known as mine and mill tailings. At their McClean Facility in Northern Saskatchewan, AREVA Resources Canada disposes of the tailings waste using the JEB Tailings Management Facility (TMF). AREVA monitors the mineralization of elements of concern (i.e., Ni, As, Fe, Mo, Ra, and U) within the TMF as part of its on-going commitment towards managing the facility’s environmental impact. Molybdenum (Mo) is predicted to mineralize as insoluble powellite (CaMoO4) within the TMF. However, no experimental evidence confirmed the presence of powellite in the TMF. In Chapter 2, the presence of powellite, and other Mo-bearing minerals, was determined using powder X-ray diffraction (XRD), X-ray fluorescence imaging, and Mo K-edge XAS. The results of this study confirmed that powellite was present in the TMF and showed that Mo K-edge XAS was the only effective way to detect the Mo minerals within the TMF. New materials for use as nuclear fuels were also investigated in this thesis. Spent nuclear fuel must be securely stored for long periods of time due to the presence transuranic elements (TRU; i.e., Pu, Am, Np, Cm), and the use of inert matrix fuels (IMF), which consist of actinides embedded in a neutron transparent (inert) material, have been proposed for to “burn-up” or transmute these TRU species. Stabilized ZrO2 materials have been proposed for use in IMF applications, and in Chapter 3 the thermal stability of a series of NdxYyZr1-x-yO2-\delta materials made by a ceramic synthetic route have been studied using powder XRD, scanning electron microscopy (SEM), and X-ray absorption spectroscopy. (Nd was used as a surrogate for Am.) The results of this study showed that the fluorite structure of the NdxYyZr1-x-yO2- \delta materials was stabilized when y >= 0.05, and that the local environment around Zr was independent of composition or annealing temperature. The effect of synthetic method on the thermal stability of the NdxYyZr1-x-yO2-\delta materials was also determined, and this is the subject of Chapter 4. In this study a series of NdxY0.25-xZr0.75O1.88 materials were synthesized using a low-temperature co precipitation synthesis, and these then annealed at 1400 °C and 1500 °C. The as-synthesized and annealed materials were characterized by powder XRD, SEM, and XAS. This study confirmed that the thermal stability of the materials was dependent on synthetic method, and that materials made using a solid-state method were superior to those produced by a solution-based approach. Y-stabilized zirconia has a low thermal conductivity, which is not ideal for a nuclear fuel. The thermal conductivity could be increased if a lighter cation, such as Sc, was used to stabilize the fluorite structure. In Chapter 5, the thermal stability of a series of NdxScyZr1-x-yO2-\delta materials was investigated. The as-synthesized and annealed materials were studied by powder XRD, SEM, and XAS. These results showed that the fluorite structure was only stable in the annealed materials when x+y >= 0.15 and y >= 0.10. The results of this study provided insight into the possible use of scandia-stabilized zirconia for use as an inert matrix fuel. This studies presented in this thesis have used X-ray absorption spectroscopy and a number of other techniques to characterize materials important to the nuclear fuel cycle. The studies presented here were only possible because of the unique information that can be obtained using XAS. This thesis serves to highlight the importance of XAS as a technique and how it can be applied to solve problems related to the material science of the nuclear fuel cycle.

<p>A lot of mine waste rock and tailings arise from all mining processes and have to be stored in an appropriate way. Tailings are deposited in impoundments retained by tailings dams. The objective of tailings dams is to retain the slurry from the mining process and in that way prevent spill into the surroundings that might be harmful for the environment. Tailings dams are often constructed as staged embankments so that construction costs and demand of materials are spread more evenly over the period of deposition.</p><p>The objective of this thesis has been to compile information about and evaluate events at Swedish tailings dams and also to develop a collective database for all Swedish mining companies for all tailings dams and all events that occur at tailings dams.</p><p>Information about 60 events at Swedish tailings dams has been gathered and evaluated. The evaluation has been performed by comparison between and analysis of individual parameters and also by use of a multivariate statistical method called PLS. The statistical analysis shows a decrease in the numbers of events during the last five years, which indicates improved dam safety within the mining industry. The analysis also shows that severe events and the human factor might be related when it comes to the initiating cause of the event. Further relations between the parameters and the severity of the events can be seen from the PLS-analysis, for example that low and short tailings dams to a greater extent are subjected to severe events. To be able to draw more reliable conclusions further studies with a more complete basic data are needed.</p><p>This work has shown a need of a collective database within the Swedish mining industry for tailings dams and occurring events at tailings dams so that more complete basic data could be obtained for future studies. A structure for such a database has been developed in Microsoft Access 2000. The aim of the database is to facilitate feedback within the mining industry and to gather comprehensive data for future statistical evaluations.</p> / <p>Vid alla gruvprocesser skapas stora mängder restprodukter i form av gråberg och anrikningssand som måste tas om hand på lämpligt sätt. Anrikningssanden deponeras tillsammans med vatten från gruvprocessen i magasin omgärdade av dammvallar, s.k. gruvdammar. Gruvdammar har som syfte att hålla kvar anrikningssand och vatten och måste vara stabila så att de skyddar omgivningen från utsläpp av anrikningssand som skulle kunna vara skadligt för miljön. En gruvdamm byggs ofta upp i etapper eftersom byggkostnaderna och behovet av dammfyllnadsmaterial då sprids över tiden.</p><p>Syftet med arbetet har varit att sammanställa och utvärdera händelser vid svenska gruvdammar samt att utforma ett för gruvindustrin gemensamt dammregister och felrapporteringssystem.</p><p>60 händelser vid svenska gruvdammar har sammanställts och utvärderats. Utvärderingen har genomförts dels genom att enskilda parametrar jämförts och analyserats och dels med hjälp av den multivariata analysmetoden PLS. Den statistiska analysen visar på en minskning i antal händelser under de senaste fem åren, vilket tyder på ett förbättrat dammsäkerhetsarbete inom gruvindustrin. Analysen har kunnat uppvisa ett samband mellan allvarliga händelser och den mänskliga faktorn när det gäller vad det är som initierat händelserna. Genom PLS-analysen har ytterligare samband mellan de undersökta parametrarna och allvarlighetsgraden av händelserna kunnat utläsas, bl.a. visar analysen att låga och korta dammar i större utsträckning drabbas av allvarliga händelser jämfört med höga och långa dammar. För att säkra slutsatser ska kunna dras krävs dock vidare studier med ett mer komplett statistiskt underlag.</p><p>Examensarbetet har påvisat ett behov av ett branchgemensamt damm- och felrapporteringsregister för att ett mer komplett underlag ska kunna erhållas i framtiden. En färdig databasstruktur för ett sådant dammregister och felrapporteringsregister för svenska gruvdammar har utformats. Databasen är uppbyggd i Microsoft Access 2000 och är tänkt att underlätta erfarenhetsåterföring inom branschen samt att ge ett underlag för framtida statistiska undersökningar.</p>

No description available.

Storage of mine tailings and waste concrete imposes economical and environmental impacts. Researchers have attempted to reuse wastes as construction material by utilizing ordinary Portland cement (OPC) to stabilize them. This method, however, has a number of limitations related to OPC. In this research, a recent technology called geopolymerization is used to stabilize mine tailings and concrete waste so that they can be completely recycled and reused. The research includes three main parts. The first part studies the effect of different factors on the mechanical properties, micro/nano structure, and elemental and phase composition of mine tailings-based geopolymer binder. The second part investigates the feasibility of producing geopolymer bricks using mine tailings. The physical and mechanical properties, micro/nano structure, durability, and environmental performance of the produced bricks are studied in a systematic way. Moreover, the enhancement of the mine tailings-based geopolymer bricks by adding cement kiln dust (CKD) is studied. The third part of the research investigates the recycling of the fines fraction of crushed waste concrete to produce binder through geopolymerization in order to completely recycle concrete waste. The results indicate the viability of geopolymerization of mine tailings by optimizing the synthesis conditions. By properly selecting these factors, mine tailings-based geopolymer bricks can be produced to meet the ASTM standard requirements and to be environmentally safe by effectively immobilizing the heavy metals in the mine tailings. The physical and mechanical properties and durability of the mine tailings-based geopolymer bricks can be further enhanced by adding a small amount of CKD. The results also show that the fines fraction of crushed waste concrete can be used together with fly ash to produce high performance geopolymer binder. Incorporation of calcium in the geopolymer structure and coexistence of the calcium products such as CSH gel and the geopolymer gel explains the enhancement of the mine tailings-based geopolymer bricks with CKD and the high performance of geopolymer binder from the waste concrete fines and fly ash. The research contributes to sustainable development by promoting complete recycling and utilization of mine tailings and concrete waste as construction material.

Mining activity is suspected of contributing sulfate and total dissolved solids (TDS) to ground water downgradient of the Pima mining district. High ionic concentrations in tailing impoundments suggest that tailings-pond recharge may be a source of the contamination. Experiments indicated that sulfate is not significantly produced by inorganic sulfide oxidation in the tailings ponds. Tailings pond water chemistries were compared with historical water quality analyses in the Pima district. The U.S.G.S. computer program PHREEQE modeled saturation indices for anhydrite, calcite, fluorite, and gypsum in water chemistries throughout the study area. Well water downgradient of the mines had lower saturation indices than tailings pond water which discredits the claim that tailings-pond recharge is acquiring salts as it percolates to the aquifer. Evidence supports the opinion that tailings pond seepage is contributing to the sulfate and TDS content in ground water downgradient of the ponds.

Mineral Liberation Analyzer (MLA) is an automated mineralogical system originally developed to characterize ore and mill feeds for the metallurgical processing industry. Its ability to quantitatively characterize solid and particulate material, including whole rock thin sections, waste rock, tailings, soil, and sediments, has led to increasing applications in other industries. The software uses back-scatter electron imagery and energy dispersive X-ray analysis to analyze each particle’s shape, size, and mineralogical information. Energy dispersive X-ray data are compared to a user-generated Mineral Reference Library consisting of known phases and corresponding EDS spectra to classify each particle. MLA is used in this study to provide quantitative assessments of mining-related environmental samples to answer questions regarding mineralogical controls on bioaccessibility, metal leaching/acid rock drainage potential, and anthropogenic influence. Six tailings samples from the New Calumet Mine in Quebec, Canada, were analyzed using MLA. Gastric Pb bioaccessibility testing and total metal content performed on these samples indicated that Pb bioaccessibility in the <250 micron size fraction was not directly correlated with the total Pb concentration. This suggested that there were mineralogical and/or physical controls on bioaccessibility. MLA was used to quantify the relative proportions of cerussite, a highly bioaccessible Pb carbonate, and galena, a lower bioaccessibility Pb sulfide. Liberation and particle size were also analyzed as controls on bioaccessibility. Sample GD-VEG1 (highest bioaccessibility) has the highest ratio of cerussite to galena, the smallest particle size, and the most liberated Pb-bearing particles. The New Calumet tailings were also analyzed using static testing, a suite of laboratory tests used by environmental scientists and mine operators to operationally define acid rock drainage and metal leaching potential. Modal mineralogy obtained from MLA analysis was used to calculate neutralization potential (NP) and acid potential (AP), taking into account the presence of iron carbonate minerals and iron-bearing sulfides other than pyrite. Results are within several units of those obtained by static testing. Two Ni-impacted soil samples collected from the region of Kalgoorlie, Australia were characterized using MLA. Previous studies had focused on bioaccessibility and sequential extraction testing and minor mineralogical work. Preliminary XANES characterization conflicted with mineralogy predicted from sequential extraction and EMPA and MLA were used to quantitatively characterize major Ni-bearing phases and resolve previous discrepancies. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-08-24 08:13:18.722

Background: Tailings dam workers are exposed to tailings dust that has a potential health risk due to the element contents in the dust. The extent of exposure of tailings dam workers is unknown. Consequently, the elements, level of exposure, the potential adverse effects to health, compliance to legislative requirements and the efficiency of the current control measures were investigated. Design and Method: During the trials, 69 personal dust samples were collected during three full production shifts from tailings dam workers in three different tailings dam environments. The field filters were weighed to calculate the total dust concentrations. Bulk samples and field filters were analysed using the 32-element and particle size distribution scans. The between-dam, between-days and between-group variances were determined to assess the changes in exposure levels. Results: The tailings dam workers were not overexposed to tailings dust. Mean exposures were below the OEL for PNOC, measuring 0,124 mg/m3 (TD 1) 0,366 mg/m3 (TD 2) and 2,956 mg/m3 (TD 3). Three outliers in the data were present in TD 3 and exceeded the action level for PNOC. A major part of the particle size distribution consisted of inhalable sizes (>I0 μm). Cyclone tailings dams have smaller particle sizes than spigot tailings dams, though 85% of the particles in all tailings dams were larger than 10 μm. Some elements identified in the dust have potential respiratory health effects. No significant differences existed between the three tailings dams regarding tailings dust concentrations (p=0,527 on 5% significant level and p=0,292 on 10% significant level). There was, however, a significant difference on a 5% significant level between the days (p=0,003 and p=0,006). The workers on the cyclone tailings dams had smaller exposures than workers on the spigot tailings dams, and the pipeline labourers were more exposed than the mudguards. The tailings dams did comply with legislative control measures. However, washing facilities for the cleaning of overalls due to elements in the dust, such as nickel, chromium and manganese need to be considered. Workers need to be educated in work practices and procedures, personal hygiene and symptoms that can be experienced after exposure. Engineering control measures such as water sprayers covering the entire tailings dam, the use of fixed or temporary windscreens in the area where work is done and covering of the roads on the tailings dam with gravel or water spray can be considered as dust suppressant controls. Conclusion: The study met the issues set out in chapter 1, hypotheses were rejected and accepted and future studies were suggested. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2007.