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1
Hottenstein, John, and John Hottenstein. "Soil Microbiome Dynamics During Pyritic Mine Tailing Phytostabilization." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/623146.
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Challenges to the reclamation of pyritic mine tailings arise from in-situ acid generation that severely constrains natural revegetation. While microbial communities that participate in acid generation through iron and sulfur (FeS) oxidation in acidic aquatic environments are well studied, relatively little information is available concerning the initial dynamics of in-situ soil acidification due to microbial FeS oxidation that occur in moderately acidic conditions. This research characterizes the taxonomic composition and behavior of microbial FeS oxidizing communities across a pH gradient from moderately acidic to highly acidic environmental conditions. We combine results from a 7-year compost-assisted phytostabilization field study with a controlled microcosm enrichment experiment that was conducted in an artificial soil matrix to follow the influence of pH on development of the soil microbiome. Microcosm results show that biological activity significantly increases the acidification rate in moderately acidic pH conditions in comparison to abiotic controls. Taxonomic profiles of the microbial communities in the microcosms and from the field study reveal that populations associated with both heterotrophic and lithotrophic activity (Alicyclobacillaceae, Acetobacteraceae and Xanthomonadaceae) dominate during acidification in moderately acidic conditions. These results suggest that chemoheterotrophs are an important element of the microbial community that help enable, directly and indirectly, lithotrophic FeS oxidation across moderately acidic conditions. Taken together, this research suggests that shifts of microbial populations associated with pH transitions have the potential to be used as bioindicators of the present and future status of the phytostabilization process.
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Johnson, Lawrin Von. "THE DESIGN OF STABLE AGGLOMERATES FOR MINE TAILING LEACH HEAPS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275239.
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Huggins, Grant. "Electro-kinetic treatment of a quartz-illite tailing." Thesis, Federation University Australia, 2000. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/164870.
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"The purpose of the study is to determine what use electro-kinetics may have to the minefilling process. It also examines what possible use it may have in other mining areas, where stabilising fine soils can improve the mining process. A review of minefilling methods and the general use of electro-kinetics is performed to support this examination."Master of Engineering Science
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Turk, Colleen Mary 1961. "The effect of microorganisms on soil structure development in copper mine tailing." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/291594.
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Organic matter amendments have long been known to improve native organic matter content, aggregation and structure of soils. In the laboratory, however, organic matter amendments to autoclaved soils have no such effect. This may explain the failure of many reclamation attempts on mine tailing wastes, which often proceed without regard for the microbiological processes necessary for soil formation and cycling of plant nutrients. In this study, incubation of tailing waste with soil microbes and a simple carbon source proved sufficient to increase the formation of water stable aggregates from tailing particles. Autoclaved control samples showed no change in aggregation. The incorporation of microbial cell mass into the mineral matrix of the tailing was observed using scanning electron microscopy. These results suggest that microbial activity is necessary in order to incorporate organic matter into the abiotic matrix of tailing, promoting aggregation and ultimately soil formation from this material.
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Kastyuchik, Alexey. "Evaluation of alkaline electro-activated water and eggshell as acid mine drainage neutralization and mine tailing remediation agents." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26072.
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Cette étude visait à étudier la capacité d’un biodéchet calcitique seul ou en mélange avec de matériaux chimiques alcalins ainsi que l’efficacité du procédé d’électro-activation dans la neutralisation de l’acidité et le maintien de conditions alcalines dans un résidu minier sulfuré (RMS). Dans une première série d'expériences, l’évolution du pH du RMS traité avec divers amendements a été suivie en fonction de doses croissantes de coquilles d'œufs de poule (COP) ajoutées seules (2, 4, 6, 8 et 10%) ou en mélange avec 1 et 2% de ciment Portland, 1 et 2% d’oxyde de magnésium (MgO), 1 et 2% de chaux calcique et 1 et 2% de chaux dolomitique. La plus forte dose de COP (10 %) a augmenté la valeur de pH de 2,61 (sans ajout d’amendement) à 7,24. Cependant, les échantillons de RMS mélangés avec COP + ciment (1 – 2%) ou COP + MgO (1 – 2%) avaient un pH très élevé (≥ 8). Les résultats suggèrent que les composés de magnésium ou les produits calcaires riches en oxydes, en hydroxydes et en carbonates, présents dans les RMS chaulés, fournissent une protection à longue terme contre l’acidification anthropique des RMS chaulés. Dans une deuxième série d'expériences, plusieurs essais ont été effectués pour évaluer l’efficacité du procédé d’électro-activation utilisant deux compartiments, l’anode et la cathode, et certains paramètres géométriques, électriques, qualitatifs et quantitatifs, dans la neutralisation de l’acidité des suspensions de RMS introduites dans le compartiment cathodique. Tous les traitements ont influencé de façon significative les valeurs de pHcatholyte. Les résultats ont démontré que l’électro-activation permettait de neutraliser efficacement l’acidité du RMS seul ou en mélange avec COP et également d’obtenir des valeurs de pH fortement alcalines (pHcatholyte 8,0 – 10,0). En outre, l’électro-activation utilisant trois compartiments a permis d’éliminer 80% du fer ferreux d’une solution de FeSO4·7H2O.This study aimed to investigate the capacity of a calcite biowaste alone or mixed with alkaline chemical materials and the efficiency of the electro-activation process in neutralizing acidity and maintaining alkaline conditions in a sulfide mine tailing (SMT). In a first set of experiments, chicken eggshell residue (CES) alone (2, 4, 6, 8 and 10%) or mixed with cement concrete (1 – 2%), MgO (1 – 2%), calcitic limestone (1 – 2%) or dolomitic limestone (1 – 2%) was used to neutralize sulfide mine tailing (SMT) acidity and to precipitate trace metallic elements. The highest rate of CES (10%) increased the initial tailing pH value from 2.61 (without amendment) to 7.24, indicating that CES had sufficient lime value to increase the pH of acid SMT. However, the SMT samples mixed with either CES + cement (1 – 2%) or CES + MgO (1 – 2%) had a high pH (≥ 8). The results suggested that magnesium compounds and calcareous products rich in hydroxides, oxides and carbonates present in limed SMT would provide long-term protection against acid deposition or re-acidification of limed SMT. In a second set of experiments, several trials were carried out to assess the effectiveness of electro-activation process composed by two compartments, anode and cathode, under different electric, geometrical, quantitative and qualitative parameters, in neutralizing acidity and maintaining alkaline conditions in a SMT alone or mixed with CES introduced into the cathode compartment. All treatments significantly influenced the pHcatholyte. The results demonstrated that electro-activation process is capable of neutralizing the acidity of RMS alone or mixed with COP and also to achieve alkaline pH conditions (pHcatholyte 8.0 – 10.0). In addition, the electro- activation process using three compartments can remove up to 80% of ferrous iron from an aqueous FeSO4·7H2O solution.
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Feng, Qingming. "Applying Mine Tailing and Fly Ash as Construction Materials for a Sustainable Development." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/594926.
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Geopolymerization has been considered as a new technology to replace the ordinary Portland cement in construction industry. It provides an option to manage the industry waste and byproducts like fly ash, mine tailings. At the same time, the CO₂ emissions can be reduced about 80% compared to that of ordinary Portland cement. The present research includes three main parts. First part is applying mine tailings as construction materials using geopolymerization method. The study is focused on efficiently activating mine tailings, reducing alkali consumption, decreasing curing time and improving compressive strength. We investigate the activation temperature effects, the impacts of additives and effects of forming pressures. The results show that a 40 MPa unconfined compressive strength (UCS) can be achieved with the geopolymerization samples after mine tailings are activated by sodium hydroxide at 170°C for 1 hour with the addition of calcium hydroxide and alkali dissolved aluminium oxide, further compressed with a 10 MPa forming pressure and finally cured at 90°C for 3 days. To elucidate the mechanism for the contribution of additives to geopolymerization, microscopic and spectroscopic techniques including scanning electron microscopy/ energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy are used to investigate the micro/nanostructure and the elemental and phase composition of geopolymerization specimens. The stress-strain behavior was also characterized. The results shows that the mechanical behavior is similar with that of concrete and the dynamic modulus is 22 GPa, which is comparable with that of concrete. The Young's modulus of geopolymer product was also calculated and the value is in the range of 2.9 to 9.3 GPa. The findings of the present work provide a novel method for the geopolymerization of mine tailings as construction materials. Second section is applying fly ash as a high strength water-resistant construction material. Through the present investigation, a procedure has been studied. The experiment results indicate that the concentration of NaOH, water content, and curing condition can significantly affect the mechanical property of geopolymer matrix. At the same time, the chemical composition, especially the Si/Al ratio and calcium content, is also an important factor during geopolymerization. XRD results show that the amorphous feature can be observed for both high and low calcium fly ash. It is the key of the success of geopolymerizaton due to its high reactivity. XRD, FTIR and SEM tests were performed to study how experiment conditions and the properties of fly ash affect geopolymerization. The obtained compressive strength of the geopolymerization product can reach above 100 MPa. The stress-strain behavior was also characterized. The results shows that the dynamic modulus is 36.5 GPa. The product obtained from the present work shows very high water resistance without losing any compressive strength even after a one month soaking time. Third part is applying the mixture of class C fly ash and mine tailings as construction materials. Through the present investigation, a protocol has been set up. The experiment results of the present work also help set up the working conditions such as activation temperature and time, the concentration of NaOH, the addition of Ca(OH)₂, forming pressure, mine tailing to class C fly ash weight ratio, curing temperature and curing time. To elucidate the mechanism for the contribution of additives to geopolymerization, microscopic and spectroscopic techniques such as SEM/EDX, X-ray diffraction and FTIR spectroscopy were used to investigate the micro/nanostructure and the elemental and phase composition of geopolymerization composite. The obtained compressive strength of the geopolymerization product can reach above 60 MPa. The stress-strain behavior of the geopolymer matrix of the mixture of mine tailing and fly ash were also characterized and the results show that the mechanical behavior is similar to that of concrete with a 24 GPa dynamic modulus. The Young's modulus of geopolymer product was also calculated and the value is in the range of 4.0 to 13.5 GPa. The findings of the present work provide a novel method for the geopolymerization of the mixture of mine tailings and class C fly ash as construction materials, such as bricks for construction and road pavement.
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Huston, Robert Edward. "Mixed metal/metalloid interactions affecting bioavailability : with particular reference to mine tailing risk assessment /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18757.pdf.
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Hussain, Fida 1956. "THE RELATIVE EFFECTS OF INSITU DRYING AND SAMPLE PREPARATION DISTURBANCE ON THE COMPRESSIBILITY OF A COPPER MINE TAILING." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275562.
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Rammika, Modise. "An ion imprinted polymer for the determination of Ni (II) ions from mine tailing samples." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1004981.
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A Ni(II)-dimethylglyoxime ion imprinted polymer {Ni(II)-DMG IIP} was synthesized by the trapping method using the bulk polymerisation format. The structures of the imprinted and non-imprinted polymer were evaluated by infrared spectroscopy and the morphology was observed by scanning electron microscopy. The Ni(II)-DMG IIP was optimised for pH, mass, time and by the uniform design experimental method for the molar ratios of monomer to crosslinker to porogen and template to ligands as well as keeping these parameters constant and varying the quantities of initiator, 2,2'-azobisisobutyronitrile (AIBN). The optimum pH was 8.5, optimum mass was 50 mg, optimum time was 1 min and the optimum molar ratios of crosslinker to monomer, monomer to template and nickel(II) sulfate hexahydrate (NiSO₄.6H₂O) to 4-vinylpyridine to dimethylglyoxime were found to be 3.3:1.0, 0.6:1.0 and 1.0:0.6:3.6 respectively with 30 mg and 8 mL as the optimum amounts of initiator and porogen respectively. Through this optimisation, recovery of Ni(II) was increased from 98 to 100%. Selectivity of the ion imprinted polymer was evaluated by analysing, using an inductively coupled plasma-optical emission spectrometer, for Ni(II) ions that were spiked with varying concentrations of Co(II), Cu(II), Zn(II), Pd(II), Fe(II), Ca(II), Mg(II), Na(I) and K(I) in aqueous samples. Selectivity studies also confirmed that the ion imprinted polymer had very good selectivity characterised by % RSD of less than 5 %. Co(II) was the only ion found to slightly interfere with the determination of Ni(II). The limits of detection and quantification were found to be 3x10⁻⁴ μg/mL and 9x10⁻⁴ μg/mL respectively. The method was evaluated by a custom solution of ground water certified reference material (SEP-3) and sandy soil reference material (BCR-142R) and the concentrations of Ni(II) obtained were not significantly different to the certified ones. The Ni(II)-DMG IIP was then evaluated in aqueous and soil samples where recoveries of 93 to 100% and 98 to 99% respectively were obtained with enrichment factors ranging from 2 to 18 in aqueous and 27 to 40 in soil samples. Finally, the Ni(II)-DMG IIP was used to analyse mine tailings samples and Ni(II) recovery of 99% was obtained with an enrichment factor of 2.
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Alarcon, Leon Edgardo. "Pyrite weathering and lithium (Li?) transport under unsaturated flow conditions in model and mine-tailing systems." University of Western Australia. School of Earth and Geographical Sciences, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0011.
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[Truncated abstract] As mineral deposits continue to be mined, the non economic gangue materials such as sulphides (e.g. pyrite) that are extracted as part of the ore body or overburden are deposited within the waste rock and/or milled tailings. As a result of natural weathering processes, these reactive materials represent a potential hazard to surrounding environments. A major consequence, resulting from mine-waste impoundments containing sulphidic materials, relates to the offsite movement of low pH leachates containing elevated concentrations of metal ions posing a contamination threat. The processes and mechanisms acting in the formation of acid mine drainage (AMD) are highly variable and, to a high extent, controlled by climatic conditions as the main driver of water flow and wetness of the system which in turn determines the availability of oxygen as well as water for pyrite weathering. In particular, this thesis is based on the hypothesis that in semiarid and arid climates the acid production may be water … The experiments were repeated at different water contents ranging from 0.24 to 0.33 cm3 cm-3. Breakthrough curves (BTC) of Li+, K+, Ca2+, Mg2+, Na+ and pH were measured and described with models of different complexities. This included the use of a simple linear and non-linear isotherms for Li+ alone, a binary Li+ - K+ ion exchange, and a complete multicomponent chemical equilibrium description of ion transport. The latter, by including dissolution of primary minerals which released base cations such as Mg2+, Ca2+ and K+ explained some of the elution patterns of base cations for which the Li+ - K+ exchange was the dominant process. Furthermore, under unsaturated water flow conditions, retardation of Li+ increased with decreasing water content. Thus solute mobility in mafic rock tailings appears to decrease under strongly unsaturated water flow conditions.
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Wu, Changhong. "Acid mine drainage prediction techniques and geochemical modelling: case study on gold tailing dams, West Rand, Witwatersrand basin area, South Africa." University of the Western Cape, 2021. http://hdl.handle.net/11394/8401.
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Doctor ScientiaeAcid Mine Drainage (AMD) is identified as one of the contributors to environmental hazard in the gold mining region of South Africa, as caused by the mining operational activities performed by mining industries in South Africa. This effect motivates the development of AMD prediction techniques application and geochemistry modelling using gold tailing dams located in West Rand area, Witwatersrand Basin as a case study. Control strategies are devised to assess, understand and measure the acidic potential generation of waste materials in ensuring the right method required to analyse risks caused by AMD to environment. The method encompasses mineralogical and geochemical analysis of 93 samples collected, AMD prediction, test modification and geochemical modelling. This method was appropriately applied to understand the basic mechanisms involved in controlling acid generation, assessing prediction procedure and selecting the right prediction tools. Study objectives are attained by performing a series of experimental lab tests on the samples collected from the two major tailing dams (Mogale and Gold One_1 tailings). Results derived from the lab experiments (XRD and SEM-EDS) show presence of mineral phases characterised with the surface feature of samples, and unknown substances of samples were identified. Geochemical characterisation was performed by XRF and ICP-MS to determine the major oxides elements and trace elements, respectively. Leco test generate total sulphur and total carbon. Multistatistical analysis is used to interpret the data derived from geochemical characterisation process to explicate the metal and trace elements distribution and occurrence. Initial samples were screened and categorised based on paste pH and EC using kinetic tests to determine acid-forming and neutralising minerals in samples and static tests to determine acid generation potential in samples. Net Acid Producing (NAPP) was mathematically calculated from Acid Neutralising Capacity (ANC), Maximum Potential Acidity (MPA) and total Sulphur. Results obtained from the Paste pH demonstrate that samples collected from 1 meter downward the holes to 10 meters, with a few meters samples in hole T003 at Gold One_1 are non-acidic while the remaining tailing samples are acidic. ANC/MPA ratio was applied to assess the risk of acid generation from mine waste materials. Graphical illustrations of the Acid Base Account (ABA) are plotted to demonstrate the net acidic generation potential trends of samples, which were classified into non-acid forming, potential acid forming and uncertain categories. Results integration between ANC, Single Addition Net Acid Generation (NAG) test and NAPP were used to classify acid generation potential of the samples. Leachate collected from leaching column test were analysed for pH, EC and chemical element by ICP-MS. The leaching column test used to analyse samples (T004) and (T001) collected from the two major tailings was set up for a 4-month experiment. Study findings present environmental assessment report on the two investigated gold tailing dams in Witwatersrand Basin area. Other findings are improved understanding of the application and limitations of various existing AMD prediction methods for assessment of gold mine waste and conceptual geochemical modelling developed to test appropriate methodology for AMD potential at a given gold mine site.
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Kiventerä, J. (Jenni). "Stabilization of sulphidic mine tailings by different treatment methods:heavy metals and sulphate immobilization." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526223964.
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Abstract Millions of tons of mine tailings are generated worldwide annually. Since many valuable metals such as Ag, Cu, Pb, Zn, Au and Ni are usually incorporated into sulphidic minerals, a large proportion of the tailings generated contain high amounts of sulphates and heavy metals. Some of these tailings are used as paste backfill material at mining sites, but large amounts are still being deposited into the tailings dams under water coverage. Sulphidic minerals are stable underground but after mining of the ore and several processing steps these minerals can be oxidized when they come into contact with water and air. This oxidation generates acid and thus reduces the pH of the surrounding environment. Furthermore, the heavy metals present in the mine tailings can be leached into the environment. This phenomenon, called Acid Mine Drainage (AMD), is one of the most critical environmental issues related to the management of sulphidic-rich tailings. Since AMD generation can still occur hundreds of years after closure of the mine, the mine tailings need stable, sustainable and economically viable management methods in order to prevent AMD production in the long term. The aim of this PhD thesis was to study various solidification/stabilization (S/S) methods for the immobilization of sulphidic mine tailings. The main focus was to develop a suitable chemical environment for achieving effective heavy metal (mainly arsenic) and sulphate immobilization while simultaneously ensuring good mechanical properties. Three treatment methods were tested: alkali activation, stabilization using hydrated lime (Ca(OH)2) and blast furnace slag (GBFS), and calcium sulphoaluminate-belite (CSAB) cement stabilization. The mine tailings used in this study contained large amounts of sulphates and heavy metals such as Cr, Cu, Ni, Mn, Zn, V and As. The leaching of arsenic and sulphates from powdered tailings exceeded the legal limits for regular and inert waste. All treatment methods were found to generate a hardened matrix that was suitable for use as a backfilling or construction material, but the calcium-based binding system was the most suitable for effective immobilization of all the heavy metals (including arsenic) and the sulphates. Precipitation in the form of calcium sulphates/calcium arsenate and the formation of ettringite are the main stabilization methods employed in calcium-based stabilization/solidification (S/S) systems. Some evidence of physical encapsulation occurring simultaneously with chemical stabilization was noted. These results can be exploited further to develop more sustainable mine tailing management systems for use in the future. The tailings could be stored in a dry landfill area instead of in tailing dams, and in this way a long-term decrease in AMD generation could be achieved, together with a high potential for recyclingTiivistelmä Monet arvometallit kuten kulta, kupari ja nikkeli ovat sitoutuneena sulfidipitoisiin mineraaleihin. Louhittaessa ja rikastettaessa näitä sulfidimineraaleja syntyy miljoonia tonneja sulfidipitoisia rikastushiekkoja vuosittain. Rikastushiekat voivat sisältää myös runsaasti erilaisia raskasmetalleja. Osa rikastushiekoista hyödynnetään kaivostäytössä, mutta suurin osa rikastushiekoista läjitetään edelleen ympäristöön rikastushiekka-altaisiin veden alle. Kun sulfidipitoinen malmi kaivetaan ja käsitellään, sulfidiset mineraalit hapettuvat ollessaan kosketuksissa veden ja hapen kanssa. Hapettuessaan ne muodostavat rikkihappoa, laskien ympäristön pH:ta jolloin useimmat raskasmetallit liukenevat ympäristöön. Muodostuvia happamia kaivosvesiä voi syntyä vielä pitkään kaivoksen sulkemisen jälkeen ja ovat näin ollen yksi suurimmista kaivosteollisuuteen liittyvistä ympäristöongelmista. Lisäksi suuret rikastushiekka-altaat voivat aiheuttaa vaaraa myös ihmisille, mikäli altaan rakenteet pettävät. Rikastushiekkojen kestäviä ja ympäristöystävällisiä varastointimenetelmiä täytyy kehittää, jotta näitä ongelmia voidaan tulevaisuudessa ehkäistä. Tässä työssä tutkittiin menetelmiä, joilla kultakaivoksella syntyvät sulfidipitoiset vaaralliseksi jätteeksi luokitellut rikastushiekat saataisiin stabiloitua tehokkaasti. Työssä keskityttiin kolmeen erilaiseen menetelmään: alkali-aktivointiin, stabilointiin kalsiumhydroksidin ja masuunikuonan avulla ja stabilointiin CSAB sementin avulla. Valmistettujen materiaalien mekaanisia ja kemiallisia ominaisuuksia arvioitiin. Tavoitteena oli ymmärtää, miten eri menetelmät soveltuvat raskasmetallien (erityisesti arseenin) ja sulfaattien sitoutumiseen ja mikä on eri komponenttien rooli reaktioissa. Alkali-aktivoimalla rikastushiekkaa sopivan sidosaineen kanssa saavutettiin hyvät mekaaniset ominaisuudet ja useimmat haitta-aineet sitoutuivat materiaaliin. Ongelmia aiheuttivat edelleen sulfaatit ja arseeni. Kalsiumpohjaiset menetelmät sitoivat raskasmetallit (myös arseenin) ja sulfaatit tehokkaimmin. Sulfaatit ja arseeni saostuivat muodostaen niukkaliukoisia komponentteja kalsiumin kanssa. Samanaikaisesti rakenteeseen muodostui ettringiittiä, jolla on tutkitusti hyvä kyky sitoa erilaisia raskasmetalleja rakenteeseensa. Raskasmetallit myös kapseloituivat rakenteen sisään. Työn tuloksia voidaan hyödyntää, kehitettäessä rikastushiekkojen turvallista varastointia. Kun materiaalille saavutetaan riittävän hyvä lujuus ja kemiallinen stabiilius, rikastushiekat voitaisiin läjittää tulevaisuudessa kuivalle maalle altaan sijaan. Näin vältyttäisiin rikastushiekka-altaiden rakentamiselta ja voitaisiin vähentää happamien kaivosvesien muodostumista pitkällä ajanjaksolla. Saavutettujen tulosten perusteella rikastushiekkoja voidaan mahdollisesti tulevaisuudessa hyödyntää myös erilaisissa betonin tapaisissa rakennusmateriaaleissa
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Sayit, Emir. "An Investigation Of Geotechnical Characteristics And Stability Of A Tailings Dam." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614455/index.pdf.
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The objective of this study is to investigate the stability problems in tailing (i.e. mine waste) dams. A tailing dam is an embankment dam (made of natural borrow or tailing material) constructed to retain slurry-like mining wastes that are produced as a result of operation of mines. In the last 30 years, the stability of tailing dams has drawn much attention as a significant number of tailing dam failures have been recorded worldwide. These instability problems caused significant loss of life and damage to property in addition to environmental hazards. In this study causes of failure of tailing dams and their stability problems are investigated with respect to their geometric and material characteristics. Seepage and stability of tailing dams are studied through limit equilibrium method and finite element method. The effects of uncertainties in material properties on the stability of tailings dams is investigated. Within this context, Kastamonu-Kure copper tailings dam is used as a case study and material properties are determined by laboratory tests.
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Svahn, Joacim. "Metal release and mobility in an arctic lake due to artificial drainage : Effects of mining and sulfide oxidation." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-58306.
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The aim of this report was to investigate the potential effects of sulfide oxidation in sediments of an arctic lake, N Luossajärvi, induced by lowered water level. Lake water, potentially contaminated by metals, was pumped into a mine tailings impoundment. The water quality in the receiving water was evaluated to see if the drainage have had an effect on the water quality. Six sediment profiles were sampled. Each profile were divided into 5 cm sections and analyzed for major elements and trace metals. Water chemistry were analyzed at six sites. As, Ni and Cu had high concentrations within undrained sediments, where As levels were classified as highly contaminated (> 27 mg kg-1 dw). Trace metals had strong statistical correlation to each other indicating a common source. The PCA analyzes performed suggests that trace metals are controlled by a common factor and drained sediments showed two additional factors controlling the variance of metals. Water chemistry had overall good status, but As, Cd, Ni and Cu exceeded natural background values. Historical data on the other hand showed no statistical difference from measured values. No effects on water quality could therefore be seen after draining of the lake, proposing high precipitation of metals within the tailing or that metals is still prevailing in the drained sediments. Metal mobility were seen within the drained sediments, where only As and Cd were presumed connected to chemical weathering and where erosion and soil properties seems to be responsible for most metal mobility.
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Wang, Veronika Wei. "Analysis of seepage, contaminanttransport, compaction and safetyof the Zhaoli ditch dam, a tailingreservoir : A modeling study of a tailing reservoirwith GeoStudio." Thesis, Uppsala universitet, Luft-, vatten- och landskapslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-445983.
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Inthe mining industry people remove rock from the ground to obtain a metal ore. Afterprocessing , the uneconomic fraction called tailings is deposited as a slurry in large reservoirs .The processing adds water and chemical agents to the tailings so that the original structure ofthe material therefore changes, which make storage of tailings complicated. If a tailingreservoir c ollapse s , it can damage p roperties and life downstream . In addition, tailings maycontain contaminants that disturb living organism s and contaminated groundwater in the localarea even under normal operation s . Therefore, tracing the contaminants and study ing thestability of the tailing reservoir s are important. The aim of the thesis is to investigate seepage,contaminant transport, tailings compaction and slope stability of the Zhaoli ditch tailingsreservoir (China) during its construction and afterwards. Simulations are performed with thecomputer program GeoStudio . According to the simulations and the conditions , contaminanttransport was highly related with total head. Total head boundary conditi ons have also a largeeffect on slope stability. The area that has most vertical displacement is at the middle of thetailing s reservoir , and the greatest change of vertical displacement is located near the slope,w here the vertical displacement can increa se 0.5 meter over a 1 0 30 meter distance. Theslope stability can be different from case to case, but the original designed tailing reservoirhave a good safety factor, indicating that the slope is not going to collapse easily.Vi människor villutnyttja malm erna i marken för att skapa ett mer effektiv t industrisamhälleF ör att utvinna så myck et användbara metaller som möjligt tillsätts kemika lier och vattenunder anriknings processen, vilket gör att deponering av de vattenmättade restprodukt erna isandmagasin blir en utmaning med avseende på dammstabilitet och föroreningstransport.Eftersomdet är svårt att ändra på en färdig byggd damm för anrikningssand e n använder dettaexamensarbete av Geostudio för att simulera hur olika parameter påverkaföroreningstransport i dammen, vattenläckage från dammen samt da mmens stabilitet ochsäkerhet. Projektet har simulerat förhållanden i Zhaoli ditch damm i Kina .Simulering i GeoStudio visar att förorening sspridning är stark kopplad till den totalahydrauliska potentialen och materialets hydrauliska konduktivitet. Rand villkoren medavseende på den hydrauliska potentialen utanför dammen även har en stor inverkan pådammvallens stabilitet. De största vertikala sättningar sker i mitten av dammen, och denstörste sättningsgradient finns i dammvallens sluttning, där en vertikal sättning på 0.5 meteröver ett avstånd på 10 3 0 meter beräknas. Deformation är störst på första lagret överberggrunden. Simuleringarna visar att dammvallens sluttning är stab il med en tillräcklig högsäkerhetsfaktor.
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Adjei, Mensah Evelyne. "Dissémination environnementale du chrome en contexte minier : études physique, chimique et isotopique." Electronic Thesis or Diss., Université Paris Cité, 2022. http://www.theses.fr/2022UNIP7060.
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L'étude du cycle des métaux dans l'environnement et de l'impact de l'activité anthropique constitue un enjeu environnemental et sanitaire important. Les sites ultramafiques sont caractérisés par leur faible teneur en nutriments (N, P et K), leur minéralogie dominée par les oxydes de Fe et leur enrichissement naturel en métaux tels que Cr, Fe et Ni. Ces systèmes ultramafiques sont des sites de choix pour les compagnies minières. Les activités minières génèrent plusieurs tonnes de déchets miniers tels que les résidus miniers, les minerais peu concentrés et les terrils. Ces déchets miniers peuvent être à l'origine de pollution des eaux et des sols. Parmi les métaux naturellement présents dans les sites ultramafiques, le chrome est exploité sous forme de minerai de chromite. Le chrome existe sous deux états d'oxydation dans l'environnement. Le chrome trivalent (Cr(III)) est un nutriment ayant un rôle important dans la régulation de la glycémie tandis que le chrome hexavalent (Cr(VI)) est toxique et carcinogène. L'utilisation de la signature isotopique du Cr a été proposée en tant que traceur du Cr(VI) dans les eaux souterraines et pour évaluer les sources de contamination. A ce jour, il n'existe pas d'étude à l'échelle d'une vallée en système ultramafique qui combine spéciation et signature isotopique afin de contraindre les sources de pollution au Cr en contexte minier. Mon travail de thèse a donc pour objectif de déterminer, avec un jeu de données très complet (70 eaux, 2 chromites, 2 terrils, 1 minerai concentré, 15 sols, 5 sédiments), les sources de Cr et les processus biogéochimiques à l’œuvre dans les systèmes environnementaux, tels que les sols impactés par l'activité minière d'extraction du chrome. Le site choisi pour cette étude est la vallée de Sukinda (Inde), classé comme étant le 4ème site le plus pollué au monde en 2007. Les conséquences environnementales, sanitaires et sociales liées à un tel classement confèrent un intérêt tout particulier à ce site pour l'étude des sources de pollution du Cr et des processus biogéochimiques. Ma thèse s'articule autour de deux questions scientifiques déclinées en question spécifiques : A. Dans quelle mesure l'activité minière modifie-t-elle la mobilité, la disponibilité, la spéciation et la signature isotopique du chrome ? Peut-on tracer les sources de Cr et déterminer les processus biogéochimiques influençant la biodisponibilité du chrome dans la vallée de Sukinda grâce à la signature isotopique du chrome ? B. Quel est le devenir du Cr lorsqu'il est relargué des déchets miniers ? Quels sont les impacts des terrils sur les sols de rizières environnants ?Metals cycle in the environment and the impact of anthropic activities are major environmental concerns. Ultramafic sites are characterised by their poor content in nutrients (N, P and K), their mineralogy dominated by Fe oxides and their natural enrichment in metals such as Cr, Fe and Ni. Thus, these systems are sites of choice for the mining companies. Mining activities produce huge amounts of wastes such as overburden, low grade ores and tailings. These wastes can be the source of water and soil pollution. Among the metals naturally present in ultramafic systems, chromium is mined as chromite ore. Chromium is stable in the environment under two oxidation states. Trivalent chromium (Cr(III)) is a nutrient which plays an important role in glycemia control while hexavalent chromium (Cr(VI)) is toxic and carcinogenic. The use of Cr isotopic signature has been proposed in order to trace Cr(VI) in groundwater and assess the source of contamination. To this day, there is no study at the scale of a catchment basin which combines Cr speciation and isotopic signature in order to determine Cr sources of pollution in a mining context. The goal of this study is to determine, with a complete dataset (70 water samples, 2 chromites, 2 tailings, 1 concentrated ore, 15 paddy soils and 5 sediments), what are the sources of Cr and which biogeochemical processes are occurring in environmental settings such as soils impacted by chromite mining. The study site is Sukinda valley (India), fourth site worst polluted in the world in 2007. Environmental, sanitary and social consequences link to such a site confer a particular interest to this valley in the study of Cr sources of pollution and biogeochemical processes involved. The two main problematics detailed in this manuscript are: A. To what extent do mining activities modify Cr mobility, availability, speciation and isotopic signature? Can we trace Cr sources thanks to its isotopic signature? Can we trace the biogeochemical processes involved in Cr bioavailability thanks to Cr isotopic signature in Sukinda valley (India)? B. What is the fate of Cr once released from mining wastes? What are tailings impacts on the surrounding paddy soils?
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Yang, Fenghua. "Geopolymerization of Copper Mine Tailings." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/268596.
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Geopolymerization is a chemical reaction process, reacting SiO₂ and Al₂O₃ with alkaline solutions, which can transform aluminosilicate solids or particles to polymer materials. Geopolymers have many engineering applications such as cementation binders for construction and solidification or encapsulation of hazardous heavy metals. Mine tailings mainly consist of SiO₂ and Al₂O₃. Theoretically, mine tailings can be used as source materials for geopolymerization. However, for most researchers, they use fly ash, metakaolin or furnace slag as source minerals, because these minerals are much more reactive with alkaline solutions. Mine tailings are naturally-forming minerals and are considered to be inert in geopolymerization. How are mine tailings to be activated through different reaction conditions? We conducted several tentative or preliminary experiments to study the geopolymerization process step by step. We tried different methods to react mine tailings with alkaline solutions. Mine tailings were submerged into alkaline solutions in a plastic bucket for 6 days in room temperature (20-25 °C). We wanted mine tailings to be activated by soaking. The results were not satisfying. Then we tried to react mine tailings with alkaline solutions at 60 °C and 90 °C. After analyzing, we found that the results were not satisfying either. So, we conducted simplified geopolymerization experiments in order to better understand the chemical reaction mechanism. Pure SiO2 and Al2O3, which were two major reactants, were employed to simplify and simulate the geopolymerization process. We drew some useful conclusions such as that geopolymerization took place at elevated temperatures; Al₂O₃ almost did not react with alkaline solutions at low temperatures, etc. We conducted experiments at elevated temperatures (150 °C, 180 °C, 210 °C). Different levels of pressure (5 MPa, 10 MPa, 20 MPa) were applied to make compact specimens. After many attempts, the results were successful. The highest mechanical strength was about 20 MPa. Most importantly, we obtained polymers produced from geopolymerzation, which could be seen by naked eyes. The experiment techniques such as scanning electron microstructure (SEM) imaging and X-ray diffraction (XRD), inductively-coupled plasma mass spectrometry (ICP-MS), and unconfined compression tests (UCS) were applied to study the geopolymerization reaction mechanism and the feasibility of using mine tailing-based geopolymers as construction materials.
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Priscu, Caius. "Behavior of mine tailings dams under high tailings deposition rates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0024/NQ50240.pdf.
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Bernier, Luc Warren Lesley A. "Sulphur biogeochemistry in a mine tailings lake." *McMaster only, 2007.
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Altamirano-Soto, Pablo, Jorge Supa-Urrutia, Humbero Pehovaz-Alvarez, Carlos Raymundo, Nestor Mamani-Macedo, and Francisco Dominguez. "Filling Method Implementing Hydraulic Lime for Reusing Mine Tailings and Improve Sustainability in Conventional Peruvian Underground Mines." Springer, 2020. http://hdl.handle.net/10757/656169.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Mining in Peru has existed for several decades, and for several years, there has been no proper environmental management of the impact of this activity on the environment and society in general, whether it be gas emissions, the presence of acidic water, or the generation of mining tailings. One of the most prominent examples involve mine tailings; these are by-products of mining processing plants and are stored in a dam known as a tailings dam. Like any extraction activity, mining generates large amounts of waste material that could become potential risks to the environment and society. Using hydraulic fills, the mine tailings contained in tailings dams could be reused. These fills seek to decrease the volume of stored tailings to prevent any future dam collapses, as observed in Brazil with the Vale mining company, where its tailings dam collapsed and caused more than 200 deaths.
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Westraad, Delme. "Suction induced shear strength of gold mine tailings." Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-06102005-092115.
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Silva, Marvin Jose. "Plant dewatering and strengthening of mine waste tailings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/NQ46918.pdf.
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Adiansyah, Joni Safaar. "A life cycle assessment of mine tailings management." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59656.
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This study of life cycle assessment and environmental valuation of mine tailings management combines rheology analysis, and computer simulations. Three strategies were assessed: thickened tailings, tailings paste, and filtered tailings. Technology improvement and renewable energy were introduced in order to improve the sustainability performance of the mine tailings methods investigated. Alternative Tailings Disposal methods with filter belt press and stack cell flotation together with renewable energy helped to reduce the environmental impact and costs associated with coal tailings disposal.
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Davies, Michael Paul. "Piezocone technology for the geoenvironmental characterization of mine tailings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/NQ46335.pdf.
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Stoltz, Eva. "Phytostabilisation : use of wetland plants to treat mine tailings." Doctoral thesis, Stockholm : Department of Botany, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-299.
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Gan, Princess Rochelle. "Flotation of Yxsjöberg historical tungsten ore tailings." Thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75844.
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Tailings dams, due to their sheer size and metal content, pose safety and environmental hazards. The Småltjarnen repository, which hosts material from the largest known tungsten mineralization in Sweden named the Yxsjöberg deposit, is estimated to contain 2.2 million tons of material from previous operations when recovery rates of scheelite, chalcopyrite, and fluorite were low. The repository is also observed to contain at least four of the listed critical raw materials by the European Commission in 2017, namely tungsten, fluorite, beryllium, and bismuth. The amenability of this tailings repository as secondary sources for valuable minerals and metals supports the Raw Material Initiative and the drive of the European Union towards a more circular economy. This masters thesis is part of the REMinE (Improve Resource Efficiency and Minimize Environmental Footprint) project that aims to evaluate the amenability of historical mining waste for re-processing from the technical, economical, and environmental perspectives. The study focuses on work package 3 of the project: Identification of new processing methods for mine waste. Previous work on this repository includes geochemical characterization and physical separation through magnetic and gravity separation tests. Since scheelite, the main mineral of the deposit, is commonly recovered through combinations of gravity separation and flotation methods, it is imperative to investigate the response of the material to flotation tests. Further characterization work and flotation tests were rendered on samples from sampling location 6 (60°02'33.6"N 14°46'30.8"E). Previous work was done on samples from and near sampling location 1, which is southwest from location 6. Characterization methods performed on the material included elemental analysis through ICP-SFMS, X-ray diffraction measurements, and mineral liberation analysis as well as physical characterization through particle size distribution analysis and determination of specific gravity. Based on MLA, the material from the main samples showed good liberation by free surface which is important for flotation processes. Mineral association also showed low percentages between scheelite and other Ca-bearing minerals which is a main concern for scheelite flotation. Comparison of characterization work between the two sampling locations allows information on the repository at a larger scope. The common scheelite flotation collector sodium oleate, as well as novel formulations Atrac 2600 and Berol 8313 from Nouryon were tested in combination with the depressant sodium silicate. Based on mass recovery, grade and recovery, selectivity, required dosage, and the degree to which it is environmentally safe, Atrac 2600 at 400 g/t is deemed to produce the most positive results. Based on characterization of the material and flotation tests, an estimated 222,200 tons of -75 µm can go directly into the flotation circuit with an average grade of 0.2768% WO3 and 0.195% Cu. Approximately 15,000 tons at 0.50% WO3 and 14,000 tons at 0.224% Cu can be recovered at a single flotation. Rough mass balance of the process flowsheet indicates a Cu concentrate at 30% Cu will produce 880.50 tons, while a saleable scheelite concentrate at 65% WO3 will yield 672.16 tons from only the original -75 µm fraction of the material. Including the gravity separation tails intended to join the flotation circuit after grinding, an estimated 1,205.54 tons of scheelite at 65% WO3 and 1.860.20 tons of 30% Cu concentrate can be produced. Aside from this, the gravity separation circuit will still be able to yield 188,000 tons of 0.92% WO3 concentrate, which can be further studied if it can be beneficiated to a saleable product. Value estimation of the products for the recommended flowsheet indicate a total of US$ 17 million for the WO3 and Cu concentrates to be produced from the readily amenable -75 µm fraction to be treated directly by flotation. Inclusion of the gravity separation tails mass into the flotation feed yields a value estimated at US$32 million.
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Auld, Ryan Richard. "RE-EXAMINING TEMPORAL AND SEASONAL MICROBIAL ACID MINE : DRAINAGE COMMUNITY VARIATION." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2153.
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Acid Mine Drainage (AMD) is characterized by high metal concentrations and an extremely low pH, primarily generated by the microbial oxidation of iron sulfides from mine tailings. Research on the microbial AMD community has largely focused on Bacteria, while little information is known about the Archaeal and Eukaryote members or the seasonal patterns within the communities. Here I examined the Bacterial, Archaeal, and eukaryotic AMD seasonal microbial community, using direct sequencing techniques on AMD samples from the Copper Cliff Tailings AMD site in Sudbury, Ontario, Canada. I found large variation in the community profile and species composition between sampling times of both the Bacterial and Eukaryote communities, suggesting a dynamic community, both between and within seasons. Bacterial diversity was highest during the winter, with Acidithiobacillus dominating, while during the summer, Acidiphilium was the dominant genus. The winter Eukaryote community was dominated by classes of algae and fungi, while the majority of summer sequencing could not be classified to the class level. Few reads were obtained for the Archaeal domain, with low and similar biodiversity between seasons. Overall, the AMD community variation and abundance were found to largely correlate with drainage water and seasonal temperature.
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Wilson, Siobhan Alexandra. "Mineral traps for greenhouse gases in mine tailings : a protocol for verifying and quantifying CO₂ sequestration in ultramafic mines." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/17427.
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Mineralization of CO₂ in ultramafic mine tailings can occur on a scale that is significant relative to the greenhouse gas emissions of a mine. Consequently, some active mining operations may be able to take advantage of carbon mineralization within their tailings to offset part of their greenhouse gas emissions. The secondary Mg-carbonate minerals that form in mine tailings are safe and durable traps for carbon and their presence can represent substantial disposal of atmospheric CO₂. Hydrated Mg-carbonate minerals precipitate within mine tailings from the Diavik Diamond Mine, Northwest Territories, Canada, and the Mount Keith Nickel Mine, Western Australia, Australia. An improved understanding of the carbon cycle in mine tailings, and the contribution of mineralogical and geochemical strategies for assessing carbon mineralization in ultramafic mine tailings, are achieved by studying these sites.
Quantitative mineralogical procedures, which use X-ray powder diffraction data, are developed for quantifying low abundances of mineral traps for CO₂ within mine tailings. Quantitative mineralogical results are used to assess the amount of CO₂ stored within hydrated Mg-carbonate minerals at both mine sites, and to assist in determining which gangue minerals are the primary sources for Mg in these minerals.
Radiocarbon and stable isotopes of carbon and oxygen are used to identify the sources for carbon in secondary Mg-carbonate minerals. Isotopic analogue experiments are used to study the fractionation of stable carbon isotopes during precipitation of dypingite, a hydrated Mg-carbonate mineral, under conditions that simulate those in the tailings storage facilities at Mount Keith. The results of these experiments suggest that hydrated Mg-carbonate minerals may be precipitating out of isotopic equilibrium with the atmosphere. A carbon isotopic fractionation factor obtained for dypingite, and computational models for isotopic mixing scenarios, are used to interpret stable isotope and radiocarbon data for carbonate minerals. Although models for mixing scenarios can provide convincing fits to stable isotopic data, they are commonly inconsistent with field observations, trends in quantitative mineralogical data, and radiocarbon results. Ultimately, radiocarbon data are used to determine that most of the carbon trapped and stored within hydrated Mg-carbonate minerals at Diavik and Mount Keith is sourced from the modern atmosphere.
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Walsworth, Nicholas A. "Geographic image modelling of environmental degradation associated with acid mine drainage, Kam-Kotia Mine tailings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0015/MQ26972.pdf.
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Van, Heerden Jacobus Hendrik Francois. "Direct measurement of pore fluid suction in gold mine tailings." Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-09212005-135324/.
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Bray, Jared M. "The potential leachability of mine tailings encapsulated in structural concrete." Thesis, Colorado School of Mines, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1543471.
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The mining and milling activities associated with extraction of metals directly generates waste in the form of mine tailings. This material is one of the largest sources of heavy metal contamination via water, air, flora, and fauna in the world. The re-use of this waste as an input to a construction material such as concrete could lead to a preventive method of reducing the environmental impact. This method of encapsulation of heavy metals has been applied to paste backfill; however, the compressive strength requirements are much lower compared to the ASTM standards for structural concrete. The objectives of this study were: (a) to examine the feasibility of maintaining the structural integrity of concrete, with compressive strength of 4,000 psi or greater with a slump of 3-4 inches, when using mine tailings as a fine aggregate, (b) investigate the ability of this material to encapsulate heavy metals, sulfates, and acid.
The waste material, collected from the Pride of the West mill in Silverton, CO, was first physically and chemically characterized. After performing batch leach extraction tests, the raw mine tailing leachate contained heavy metal concentrations above conservative regulatory limits. Then, the optimal tailing to fine aggregate ratio was investigated. It was found that the compressive strength was comparable to control samples made with aggregate and the concentration of heavy metals found in the leachate were consistently low when the ratio varied below 50%. Therefore, the ASTM standard for the minimum allowable fineness modulus was used to obtain in maximum amount of mine tailings allotted in the concrete mixture.
To examine whether metals could be leached from the concrete-tails mix, three extraction fluids varying in pH were used to accelerate the weathering process. The metals of concern were shown to have been thoroughly encapsulated in the concrete matrix, with a 2-4 log encapsulation capacity when compared to the metals leached from the raw tailings. Finally, a strength development experiment was conducted to observed changes over time. It was found that the specimens that contained mine tailings maintained comparable compressive strengths as the controls cylinders, above the minimum compressive strength requirements for structural concrete.
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Tawil, Marc Rami. "Engineering properties of iron mine slimes for tailings dam stability." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10775.
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Chen, Rui. "Bio Stabilization for Geopolymer Enhancement and Mine Tailings Dust Control." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/319999.
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The first part of the thesis investigates the enhancement of fly ash-based geopolymer with alkali pretreated sweet sorghum fiber. The unconfined compression, splitting tensile and flexural tests were conducted to investigate the mechanical properties of geopolymer composite. The results indicate that the inclusion of sweet sorghum fiber slightly decreases the unconfined compressive strength (UCS), however, the splitting tensile and flexural strengths as well as the post-peak toughness increase with the fiber content up to 2% and then decrease thereafter. A durability test program containing 10 wet/dry cycles was performed to evaluate the long-term performance of the geopolymer composite related to wet/dry cycling. The results indicate that both the UCS and the splitting tensile strength of the geopolymer composite progressively decrease with the number of wet/dry cycles. The second part of the thesis investigates the utilization of biopolymers to stabilize MT for dust control. First, a fall cone method was adopted to evaluate the Atterberg limits and undrained shear strength of MT stabilized with biopolymers. The results indicate that the inclusion of biopolymers increases both the liquid limit and the undriained shear strength of MT. Two new equations are proposed for predicting the undrained shear strength of MT based on liquid limit and water content, and liquidity index. Second, an experimental program including moisture retention, wind tunnel and surface strength tests was performed to evaluate the effectiveness of biopolymer stabilization for dust control. The results indicate that biopolymers are effective in enhancing the moisture retention capacity, improving the dust resistance, and increasing the surface strength of MT. Third, a durability test program containing 10 wet/dry cycles was applied to MT samples treated with biopolymer solutions of different concentrations. The results show that the dust resistance of MT samples progressively decreases with the number of wet/dry cycles. Finally, experimental and numerical studies on the unconfined compressive strength (UCS) of MT stabilized with biopolymer were carried out. It is found that inclusion of biopolymer into MT favors the increase of adhesion between MT particles and thus the increase of the UCS of MT.
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Vazquez-Ortega, Angelica. "Mobilization of Lead and Zinc in Acid Sulfate Mine Tailings." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193339.
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In this thesis, column experiments were conducted in order to determine the effect of irrigation with local groundwater on mobilization of lead and zinc in 50 years old sulfate-acid mine tailings. In addition, the influence of soluble oxalic acid, a common rhizosphere organic acid, was assessed by varying its concentration across an environmentally relevant range. In general, metal contaminant dissolution was not affected by the presence of oxalic acid. In both tailings, Zn mobilization was higher than Pb suggesting the presence of more kinetically labile Zn phases, regardless of the treatment used. Lead mobilization was also low because effluent solutions were near to equilibrium conditions with respect to gypsum, preventing Pb dissolution from Pb-sulfate minerals. Geochemical modeling also indicated that lead release was controlled by anglesite and plumbojarosite dissolution. Zinc release appears to be controlled by Zn-talc and goslarite.
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Spence, K. J. "Investigation of flowslides from the failure of mine tailings' dams." Thesis, University of Sheffield, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285652.
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Wortmann, Heid. "Sedimentation and desiccation of gold mines." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-11052007-152710.
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Neuschütz, Clara. "Phytostabilization of mine tailings covered with fly ash and sewage sludge." Doctoral thesis, Stockholms universitet, Botaniska institutionen, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8452.
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Establishing plant communities is essential for the restoration of contaminated land. As potential cover materials, fly ash and sewage sludge can prevent formation of acid mine drainage from sulfidic mine waste. The aim of the thesis was to i) screen for plants that can be established in, and prevent leakage of metals and nutrients from sludge on top of ash and tailings, and ii) investigate root growth into sealing layers of ash and sludge. Analyses were performed under laboratory, greenhouse and field conditions using selected plant species to examine the release of Cd, Cu, Zn, N, and P from the materials. Plant physiological responses and interactions with fly ash were also investigated. The data show that plants can decrease metal and nutrient leakage from the materials, and lower the elemental levels in the leachate, but with varying efficiencies among plant species. Plants capable of taking up both nitrate and ammonium were more efficient in preventing N leakage compared with those taking up primarily ammonium. Fast growing plants could raise the pH in acidic sludge leachate, but the initial pH decrease and N leakage was not counteracted by plants. Germination in fresh sludge was problematic, but enhanced by aeration of the sludge. In general, the accumulation of metals in plant shoots was low, especially if ash was located below the sludge. Fresh ash was phytotoxic (e.g., high alkalinity, salinity and metal levels) and induced the activity of stress-related enzymes in shoots. In sealing layers of aged and cured ash, roots could grow if the penetration resistance was low, or into the surface of stronger layers if the surface had become pulverized. The roots caused dissolution of calcium-rich minerals, possibly by exudation of saccharides. Addition of sludge to an ash layer increased root growth, likely due to decreased bulk density and pH, and nutrient addition. In conclusion, with selected plant species and a properly constructed cover, metal and nutrient leaching from the materials and root growth into the sealing layer can be restricted.
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Beddoes, Paul. "Microbial Arsenic Release from Historic Gold Mine Tailings, Nova Scotia, Canada." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20174.
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The oxidation state of arsenic is an important consideration in the remediation planning for arsenic contaminated tailings, frequently associated with gold mines. As(III) is more toxic and mobile than As(V) and arsenate can be reduced by bacteria. This study focuses on the microbial arsenic release from two abandoned Nova Scotia tailings sites. DNA fragment analysis showed that the microbial ecology varied across the two compositionally diverse sites. Microbial diversity was related to the concentrations of arsenic and iron, which implies the presence of metal reducing bacteria. Known metal reducers belonging to the Geobacter and Schewanella families were identified through gene cloning. Anaerobic microcosms quantified the activity of these bacteria. High calcium tailings showed the most arsenic release, while hardpan areas showed dramatic iron reduction. The presence of reducing bacteria can therefore affect remediation planning, since the use of tailings covers or liming techniques could increase the activity and diversity of metal reducing bacteria.
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Verma, Ajay. "An investigation of resuspension and gas transfer in flooded mine tailings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0002/NQ31166.pdf.
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Mantegh, Afshin. "Evaluation of liquefaction potential of mine tailings using elastic wave velocity." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100650.
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The extensive damages resulting from static liquefaction re-emphasized the need for reliable criteria in predicting the possible development of this phenomenon. This research presents and evaluates elastic wave velocities in determining the boundary between contractive or dilative tailing materials in the laboratory. The effects of factors such as strain rate, confining pressure and fine contents on liquefaction potential of tailings are also discussed.To achieve the above objectives, an experimental investigation of the behavior of undrained tailings at confining pressures ranging from 25 to 280 kPa and under two strain rates of 0.5 and 1 mm/min was carried out using a modified Wykeham Farrance triaxial apparatus. As part of this research, a bender element system consisting of piezo-ceramic transducers placed in the loading head and base pedestal of the triaxial cell, a control box and software to generate and receive signals were developed. The system was employed to measure shear and compressive wave velocities (Vs and Vp) during both consolidation and ultimate steady state. These elastic wave velocity measurements were used to develop relationships between void ratio (e), mean effective normal stress (P') and elastic wave velocities. After consolidation, the specimens were loaded in shear under constant strain rates to determine their ultimate steady state at large strains.
The analysis of the results obtained from this research shows limited strain softening response (limited liquefaction) in fine and medium-grained tailings whereas coarse-grained tailings illustrate a strain hardening response or dilative behavior. Shear wave velocities measured during the consolidation stage show better correlation with the ones obtained from the relationships, particularly in fine and medium-grained tailings. This is due to the fact that pore water may affect compressive wave velocity measurements and cause errors in the P wave measurements.
An increase in strain rate in fine-grained tailing does not increase contractiveness, but rather does exactly the opposite. In other words, higher strain rates are associated with higher stability for fine-grained tailings. This is in contrast with the effect of high strain rates on coarse and medium-grained tailings. The membrane effect as well as vibration induced by high strain rates and low volume compressibility in coarse-grained tailings may explain the lower liquefaction resistance in medium and coarse-grained tailings under high strain rates. It should be noted that the instability region becomes larger as confining pressures increase showing more liquefaction potential under higher confining pressures.
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McGinley, Susan. "Mine Tailings Restoration: Method Uses High Grade Biosolids to Revegetate Land." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/622232.
Full text
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Benaiges-Fernandez, Robert. "Bioreduction of iron (hydr)oxides from mine tailings under marine conditions." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673411.
Full textAbstract:
Mining industry faces environmental problems concerning waste management. Given the environmental issues associated with storage of mine wastes on land, one disposal option that has gained attraction is submarine tailings disposal (STD). This practice involves disposal of mine tailings under seawater through underwater pipelines. Discharged mine wastes may be geochemically altered by microbial communities that living in the seabed have an ecophysiology that is compatible with the mine tailings. These communities (e.g., Shewanella, Geobacter) would be able to reduce the structural Fe(III) of oxides and oxyhydroxides (henceforth referred to as (hydr)oxides) of iron contained in the tailings, leading to a release of Fe(II) and Trace Elements (TEs) into the marine environment.
The present study aimed at understanding the reaction of bioreduction of iron (hydr)oxides that are contained in mine tailings and assessing the environmental impact of STD. For this purpose, different samples of iron (hydr)oxides and mine tailings were reacted in batch and column experiments in the presence of Shewanella loihica, a dissimilatory iron reducing bacteria. The release of Fe(II) and TE was monitored throughout the experiments, and the surface of the reacted oxides were examined. Geochemical simulations of the experimental data were used to quantify the extent of the overall reductive dissolution reaction. Furthermore, to understand the influence of aqueous iron in the ocean’s nitrogen cycle, a series of experiments were carried out with Fe(II) released from bioreduced iron oxides in the presence of nitrite.
Results showed that Shewanella loihica bioreduces Fe(III) from the iron (hydr)oxides contained in the mine tailings under marine conditions. The dissolution process leads to a release of Fe(II) and TEs, which are harmful for the marine environment. It was deduced that the reactive surface area of the iron (hydr)oxides is a key factor in the bioreduction process as it provides available Fe(III) and available surface, on which Shewanella loihica attach for electron transferring. However, adsorption of some of released Fe(II) onto the surface leads to a decrease in the reactive surface area, which lowers the total available Fe(III), and to a transformation of the former oxide to a new biogenic phase containing Fe2+/Fe3+ (i.e. magnetite). Moreover, it was demonstrated that the Fe(II) released promotes a nitrite removal, interfering thus with the nitrogen cycle of the ocean. The nitrite removal was
characterized using chemical and isotopic analyses, which allowed a better understanding of the mechanisms controlling the Fe(II)-N interaction and an identification of the source of nitrite reduction in the sea.
From the results, it is inferred that STD can become a major environmental concern because (1) the Fe(II) released may lead to fertilization and eutrophication of disposal sites, resulting in an oxygen depletion and an expansion of the oxygen minimum zone and (2) the TEs released bioaccumulate in the environment and trophic webs, ultimately affecting human health and social economic development.La indústria minera s’encara a un problema de gestió dels residus produïts. Degut als problemes mediambientals que provoca l’emmagatzematge terrestre de les cues mineres, la deposició submarina de les cues (STD) és una opció que ha guanyat interès en els darrers anys. Aquesta pràctica implica el dipòsit dels residus al fons marí mitjançant canonades submergides des de les indústries mineres. Aquestes cues es poden veure afectades geoquímicament per les poblacions microbianes que viuen en el fons marí i que poden tenir una ecofisiologia compatible amb els residus. Aquestes comunitats (per exemple, Shewanella, Geobacter) poden bioreduir el ferro fèrric dels òxids i/o hidròxids continguts en els residus miners, alliberant Fe (II) i elements traça (TE) al medi marí. El principal objectiu d’aquest treball va ser entendre el procés de bioreducció dels òxids i hidròxids de ferro presents en els residus miners i avaluar les conseqüències mediambientals dels dipòsits de residus al fons marí. Per dur a terme aquest propòsit, es van fer experiments de tipus batch i de columna amb diverses mostres d’òxids i hidròxids de ferro i de residus miners, les quals van reaccionar amb Shewanella loihica, un bacteri desassimilatori del ferro capaç de dur a terme la dissolució reductiva del ferro. Es va monitoritzar l’alliberament de Fe(II) i de TEs, es van observar les superfícies dels sòlids reaccionats i es va fer un model geoquímic per quantificar la bioreducció. A més a més, per tal d’entendre millor la influència del ferro en el cicle del nitrogen de l’oceà es van dur a terme uns experiments batch on el ferro bioreduït interaccionava amb nitrit. Els resultats han demostrat que la Shewanella loihica pot bioreduir els òxids i/o hidròxids de ferro continguts en residus miners en condicions semblants a les del fons marí. Aquesta dissolució bioreductiva comporta l’alliberament de Fe(II) i de TEs que poden arribar a ser perjudicials per l’ambient. S’ha deduït que la superfície reactiva dels òxids i/o hidròxids é un factor clau en la bioreducció perquè proveeix Fe(III) per bioreduir i superfície perquè els bacteris transfereixin electrons.. Ara bé, l’adsorció de Fe(II) en la superfície comporta, per una banda, la disminució de la superfície reactiva i del Fe(III) disponible i, per altra banda, la formació d’una nova fase mineral biogènica que conté Fe2+/Fe3+, és a dir una transformació a magnetita També s’ha demostrat que el Fe(II) alliberat per la bioreducció pot interferir, amb el cicles biogeoquímic del nitrogen de l’oceà. Així, el Fe(II) bioproduït desencadena l’eliminació del nitrit en el mar. Aquest procés s’ha caracteritzat utilitzant anàlisis químiques i isotòpiques. Les dades isotòpiques han servit per entendre millor els mecanismes que regulen la interacció Fe(II)-nitrogen, i per identificar l’origen de la reducció de nitrit en el medi marí. A partir dels resultats obtinguts, es dedueix que el dipòsit de residus miners al mar (STD) és un problema mediambiental perquè (1) l’alliberament de Fe(II) pot provocar una fertilització i eutrofització dels llocs on es dipositin els residus amb una disminució de l’oxigen dissolt i una expansió de la zona mínima d’oxigen i (2) l’alliberament d’ETs pot provocar una bioacumulació d’aquests elements a les xarxes tròfiques. Tot plegat afecta no només l’equilibri d’altres cicles biogeoquímics a l’oceà sinó també la salut humana i l’economia de la societat.
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Grandlic, Christopher J. "Plant Growth-Promoting Bacteria Suitable for the Phytostabilization of Mine Tailings." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195918.
Full textAbstract:
Mining activities and their resulting wastes, mine tailings, have created a sizable problem globally. Semiarid lands have been particularly impacted due to intense mining activities in these areas. Growing concerns regarding human health risks and environmental consequences associated with these tailings has created a need for efficient and effective remediation strategies. Phytostabilization, the establishment of a vegetative cover on mine tailings to reduce erosion and dispersion of material, is emerging as a cost-effective remediation technology. However, due to elevated levels of metal contaminants, acidic pH values and poor substrate quality many tailings sites are inhospitable to plant growth. The addition of compost amendments can mitigate the toxic effects of tailings material and facilitate plant growth; however, in many instances the necessary compost amendments may be cost prohibitive. The use of specialized bacterial isolates, known as plant growth-promoting bacteria (PGPB), to enhance plant growth is a developing technology that has a broad range of applications. The use of PGPB to enhance one or more aspect of plant establishment and growth has been demonstrated to be effective in hundreds of previous studies conducted primarily under agricultural settings. To date, very few studies have utilized PGPB in attempts to enhance plant growth in mine tailings. The current study is an investigation into the potential for utilizing PGPB to enhance plant growth during the phytostabilization of semiarid mine tailings. During this investigation a large collection of bacterial isolates was screened for common plant growth-promoting mechanisms such as siderophore and indole-3-acetic acid production, phosphate solubilization and ACC-deaminase activity. Isolates possessing beneficial qualities were utilized in a series of greenhouse screening studies to evaluate their abilities to enhance the growth of native desert plants in various tailings materials. A number of isolates tested have demonstrated the ability to enhance plant growth in composted and non-composted tailings material. Optimization of this technology has now indicated that alginate-encapsulated inoculation of target plants is a beneficial and practical technology.
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Santos, Alina E., Rocio Cruz-Ortega, Diana Meza-Figueroa, Francisco M. Romero, Jose Jesus Sanchez-Escalante, Raina M. Maier, Julia W. Neilson, Luis David Alcaraz, and Freaner Francisco E. Molina. "Plants from the abandoned Nacozari mine tailings: evaluation of their phytostabilization potential." PEERJ INC, 2017. http://hdl.handle.net/10150/624057.
Full textAbstract:
Phytostabilization is a remediation technology that uses plants for in-situ stabilization of contamination in soils and mine tailings. The objective of this study was to identify native plant species with potential for phytostabilization of the abandoned mine tailings in Nacozari, Sonora in northern Mexico. A flora of 42 species in 16 families of angiosperms was recorded on the tailings site and the abundance of the most common perennial species was estimated. Four of the five abundant perennial species showed evidence of regeneration: the ability to reproduce and establish new seedlings. A comparison of selected physicochemical properties of the tailings in vegetated patches with adjacent barren areas suggests that pH, electrical conductivity, texture, and concentration of potentially toxic elements do not limit plant distribution. For the most abundant species, the accumulation factor for most metals was <1, with the exception of Zn in two species. A short-term experiment on adaptation revealed limited evidence for the formation of local ecotypes in
Prosopis velutina
and
Amaranthus watsonii
. Overall, the results of this study indicate that five native plant species might have potential for phytostabilization of the Nacozari tailings and that seed could be collected locally to revegetate the site. More broadly, this study provides a methodology that can be used to identify native plants and evaluate their phytostabilization potential for similar mine tailings.
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Naguit, Christian. "Evaluating the success of revegetated metalliferous mine tailings in Manitoba and Saskatchewan." Springer Link and Business Media, 2013. http://hdl.handle.net/1993/23291.
Full textAbstract:
Revegetation is employed to mitigate the spread of mine tailings in the environment by ameliorating tailings with organics to promote plant cover. Revegetation has proven to be successful in establishing plant cover, but the long-term effects are largely unknown. A field study was conducted to evaluate the success of four artificially revegetated tailings from Manitoba by comparing plant cover and diversity. Central Manitoba, Flin Flon, and Thompson had moderate cover while cover was low in Lynn Lake. All four sites had low diversity and were composed of early-successional species. The results suggest that while current revegetation methods promote plant growth on tailings, it is currently difficult to determine if and how the vegetation will progress from a grass-legume community to a boreal forest. In addition, while various amounts of effort were invested into each site, the results indicate the degree of remediation does not affect overall success.
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Aldhafeeri, Zaid. "Reactivity of Cemented Paste Backfill." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38111.
Full textAbstract:
Mining has been one of the main industries in the course of the development of human civilization and economies of various nations. However, every industry has issues, and one of the problems the mining industry has faced is the management of waste, especially sulphide-bearing tailings, which are considered to be a global environmental problem. This issue puts pressure on the mining industry to seek alternative approaches for tailings management. Among the several different types of methods used, cemented paste backfilling is one of the technologies that offers good management practices for the disposal of tailings in underground mines worldwide.
Cemented paste backfill (CPB) is a cementitious composite made from a mixture of mine tailings, water and binder. This technology offers several advantages, such as improving the production and safety conditions of underground mines. Among these advantages, CPB is a promising solution for the management of sulphidic tailings, which are considered to be reactive materials (i.e., not chemically stable in an atmospheric condition) and the main source of acid mine drainage, which constitutes a serious environmental challenge faced by mining companies worldwide. Such tailings, if they come into direct contact with atmospheric elements (mainly oxygen and water), face oxidation of their sulphidic minerals, thus causing the release of acidic drainage (i.e., acid mine drainage) and several types of heavy metals into surrounding water bodies and land.
Therefore, the reactivity of sulphidic tailings with and without cement content can be considered as a key indicator of the environmental behavior and durability performance of CPB systems. For a better understanding of the reactivity, it is important to investigate the influencing factors. In this research, several influencing factors are experimentally studied by conducting oxygen consumption tests on different sulphidic CPB mixtures as well as their tailings under different operational and environmental conditions. These factors include time, curing temperature, initial sulphate content, curing stress, mechanical damage, binder type and content, and the addition of mineral admixtures. In addition, several microstructural techniques (e.g., x-ray diffraction and scanning electron microscopy) are applied in order to understand the changes in the CPB matrices and identify newly formed products.
The results reveal that the reactivity of CPB is affected by several factors (e.g., curing time, initial sulphate content, ageing, curing and atmospheric temperature, binder type and content, vertical curing stress, filling strategy, hydration and drainage, etc.), either alone or in combination. These factors can affect reactivity either positively or negatively. It is observed that CPB reactivity decreases with increasing curing time, temperature (i.e., curing and atmospheric temperatures), curing stress, binder content, the addition of mineral admixtures, degree of saturation, and the binder hydration process, whereas reactivity increases with increases in sulphide minerals (e.g., pyrite), initial sulphate content, mechanical damage, and with decreased degrees of saturation and binder content. The effect of sulphate on the reactivity of CPB is based on the initial sulphate content as well as curing time and temperature. It is concluded that the reactivity of CPB systems is time- and temperature-dependent with respect to other factors. Also, binders play a significant role in lowering CPB reactivity due to their respective hydration processes.
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Tanriseven, Esra Nur. "Stability Investigation Of Eti Copper Mine Tailings Dam Using Finite Element Analysis." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614675/index.pdf.
Full textAbstract:
In mining industry, waste storage is a very prominent issuein this respect, safety of storage structures is one of the leading problems in the industry. Most of the tailings dams require remedial measures, throughout their lifespan to increase their reliability. The objective of the study is to investigate stability problems of formerly constructed but newly raised Eti Copper Mine tailings dam and alternative dam geometries for future raises. Plenty of methods were developed to analyze the reliability of structures
limit equilibrium methods, finite element methods and finite difference methods are among them. In this case, stability of the dam was analyzed with finite element method under static loading conditions. In order to determine input parameters properly, disturbed samples obtained at the field investigations were used. For this purpose, several laboratory experiments were conducted to determine natural moisture content, grain size distribution, specific gravity, Atterberg limits, maximum dry density and shear strength parameters of tailings and embankment material.
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Losher, Albert Justin. "The geochemistry of sediments and mine tailings in the Alice Arm area." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24847.
Full textAbstract:
A geochemical study of the composition of natural sediments and contaminating mine tailings in Hastings and Alice Arms has been carried out. Apart from the geochemical investigation on the solid fraction, pore waters from six sediment cores have been analyzed to evaluate the diagenetic processes in the sediments of these two inlets. Differences in the mineralogy as well as in the chemical composition of the sediments were used to distinguish the natural sediments from contaminated sediments and pure tailings.
In Alice Arm, two types of tailings could be differentiated with these methods. The first tailings type originated from the Kitsault Mo-deposit, which was mined in the past two decades by the B.C. Molybdenum Corporation and AMAX/Canada. These tailings are characterized by a number of features which make them distinguishable from natural sediments. The K-feldspar content of the tailings is significantly increased, mainly at the expense of plagioclase, which is the main characteristic for the mineralogical identification of this tailings type. The enhanced K-feldspar content is the cause for increased K and Rb values in the Mo-mine tailings. Another indicator specific to these recent tailings is an increased Mo content.
The second tailings type is derived from an older mining operation in the Kitsault Valley, most likely the Dolly Varden Silver Mine. A specific indicator for these tailings is their high Ba content which is due to large amounts of barite. This mineral phase could be identified by X-ray diffraction methods in a heavy mineral fraction of the relevant sediment layers.
Both tailings types show enrichment in their Pb, Zn and S concentrations, caused by an increased amount of metal-sulphides in the ore materials. In this area, these elements can therefore serve as a general indicator for the contamination of natural sediment with either tailings type.
The interstitial water analyses indicated that the sediments in both inlets become reducing at a fairly shallow depth (10-15 cm), resulting in the mobilization of Mn, Fe and Mo from the solid phase. In the deeper parts of the cores, consumption of these metals could usually be observed which is likely due to precipitation of authigenic components. The dissolved Mo concentrations in the sediments contaminated with the modern tailings were much higher than in the natural sediments. In the pore water of the pure tailings the concentration reaches some 300 times that of the overlying water, which is the highest value ever reported for saline pore waters. These high Mo concentrations must support a flux of Mo from the sediment into the overlying water, and it is shown that such a flux could increase the inventory of naturally occurring dissolved Mo in the deep waters of Alice Arm by up to 4%.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Drysdale, Karen. "Geochemistry of a buried marine mine tailings deposit, Howe Sound, British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28982.
Full textAbstract:
One hundred surface sediment samples and two 30 cm cores were collected from Howe Sound, British Columbia, a deep (≈280 m) fjord with a restricted inner basin into which mine tailings had been dumped for 75 years. The abundances of major elements Si, Al, Ti, Fe, Mg, Ca, Na, K, C, N, and P, and minor elements Ba, Co, Cr, Cu, Mn, Ni, Pb, Rb, Sr, V, Y, Zn, and Zr were determined as well as nutrient and trace metal concentrations in porewater from the two cores.
The solid-phase data suggest that the inner basin sediments are dominated by Squamish River-derived feldspars, while the outer basin is characterized more by quartz and Fe and Mg minerals, which enter the southernmost portion of the fjord via estuarine circulation from Georgia Strait. Although Fe, Cu, Pb, Zn, and Ba are still enriched in sediments near the tailings outfall, the lapse of 13 years since cessation of tailings deposition has apparently resulted in reduced metal levels throughout much of the rest of the inlet due to ongoing dilution by natural sedimentation. Profiles of these metals with depth show that the tailings deposit proper is buried by ≈14 cm of natural sediment in the deep central portion of the inner basin.
Porewater analysis of the two cores revealed that active bacterial remobilization of organic matter is occurring at both locations; although the organic carbon content of the outer basin is greater than that in the inner basin, sulphate-reduction is more intense in the latter due to the higher sedimentation rate. Despite this, dissolved sulphides were nearly absent in porewaters, leading to the conclusion that authigenic pyrite precipitation is removing some of the dissolved Fe. Dissolved Cu and Zn are enriched in surficial porewaters of both the outer and inner basins (i.e. Cu = 215 and 132 nmol/L, respectively, and Zn = 32 µmol/L and 1.6 /µmol/L), but decrease rapidly within the top 2-3 cm, suggestive of active removal by some mechanism. Dissolved Pb concentrations were low (<3 nmol/L) in both cores, and did not show any surface enrichment. These data suggest that a strongly reducing environment such as is found at depth in natural sediments inhibits the release of some labile metals which may be contained within them.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
50
Marais, Laurette Marlize. "Characterization of bacteria isolated from a platinum mine tailings dam / Laurette Marais." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8721.
Full textAbstract:
Contamination from various sources has a huge impact on soil health and microbial community composition. Metal contamination of soil in mining scenarios is of concern and is not adequately addressed, particularly with respect to the microbial community. The mining industry is one of the largest contributors to heavy metal contamination of soil in South Africa, especially since the country is one of the major mining countries in the world. Platinum mining is of special importance, since the largest percentage of the world’s reserves of platinum group metals are found and mined in South Africa. Metals from mining activities become irreversibly immobilized in soil systems because they cannot be degraded and has a huge impact on soil systems. In this study, bacteria was isolated from soil samples collected from a platinum mine tailings dam outside Rustenburg. During the warm sampling season (March 2006) most isolates were found, especially in sites 3 and 4. During the colder and drier season (May 2006) there were less isolates. Most of the isolated cultures also displayed a wide temperature growth range, mostly between 24°C - 37°C. Paenibacillus lautus and Bacillus subtilus DN-10 had a growth range between 5°C - 40°C. Culturable metal tolerant bacteria were isolated, purified and identified using 16S rDNA sequences. Nine different species were found namely Paenibacillus lautus strain DS19, Paenibacillus lautus, Paenibacillus sp. C15, uncultured Paenibacillaceae, Bacillus subtilis strain DN-10, Bacillus sp. KDNB5, Bacillus cereus, Stenotrophomonas maltophilia and Alcaligenes sp. DJWH 146-2. The ability of these strains to tolerate metal concentrations were explored by determining their minimum inhibitory concentrations for a selection of metals e.g. aluminum, barium, cobalt, chromium, cadmium, copper, iron, lead, manganese, nickel and mercury. Most isolates were able to tolerate >5mM of the Al\Ni alloy and cobalt. Transmission electron microscopy was used to determine the location of metals inside bacterial cells and electron dispersive X-ray analysis was used to determine the levels of metals inside microbial cells. Bacillus subtilis DN-10 (LDK0306) showed a high MIC (>5mM) for most metals used, except Hg. This strain also had a high percentage (10.26%) of Pb detected in its cells by EDX. This was the highest percentage detected. Plasmids were extracted from the identified strains and can help gain a better understanding of metal tolerance mechanisms used by these isolates.Thesis(MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013