A mineração do carvão no sul de Santa Catarina se desenvolve há mais de um século e a falta de gerenciamento ambiental nos empreendimentos mineiros causou significativas alterações de qualidade nos recursos hídricos superficiais e subterrâneos da Bacia Hidrográfica do Araranguá. Além da alteração na qualidade das águas, fenômenos de abatimento de minas subterrâneas ocasionaram o fraturamento das camadas sobrejacentes, e permitiram a ampliação dos processos de circulação dos sistemas aquíferos com corpos hídricos superficiais. Como objetivo de melhorar o entendimento sobre os impactos na qualidade das águas e nas condições de fluxo subterrâneo, foram analisadas amostras das águas de 9 poços do Sistema Aquífero Rio Bonito, 4 poços do Sistema Aquífero de Leques Aluviais e 6 amostras de águas superficiais das mesmas microbacias onde estão instalados os poços. As análises hidroquímicas indicam uma predominância de águas bicarbonatadas cálcicas e sódicas, que quando em contato com a drenagem ácida de mina são transformadas em águas sulfatadas. Os valores isotópicos de δ2H e δ18O das amostras evidencia semelhança com a composição isotópica das águas meteóricas, contribuindo com a hipótese da forte interação da água subterrânea com as águas freáticas e superficiais, que ocorre devido à tectônica rúptil que afeta as litologias gonduânicas, e é intensificada pela presença das minas de subsolo. / Coal mining in southern Santa Catarina has been developed over a century and the absence of environmental management in mining projects caused significant quality changes in the surface and underground waters of the Araranguá Basin. In addition to the change in water quality, collapses have occurred in underground mines which caused the fracturing of overlying layers and allowed the expansion of aquifer systems and its integration with surface waters circulation processes. In order to better understand the impacts on water quality and groundwater flow conditions, samples of 9 wells from Rio Bonito Aquifer System, 4 wells from Alluvial Fan Aquifer System and 6 from surface waters of the same catchments were analyzed. Hydrochemical analysis indicates a predominance of calcium and sodium bicarbonate waters which when in contact with acid mine drainage are transformed into sulfated waters. The isotopic values δ2H and δ18O shows similarity to isotopic composition of meteoric waters, contributing to the hypothesis of the strong interaction between groundwater, waters from water table and surface waters, which occurs due to the ruptured tectonics affecting gondwana lithologies and it is intensified by the presence of underground mines.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Na drenagem ácida de mina a contaminação pelo manganês é notável e se caracteriza como um dos principais problemas ambientais vivenciados pela indústria mineradora. Este elemento tem sido frequentemente encontrado em concentrações muito acima do limite permitido para o lançamento que, de acordo Resolução CONAMA No. 430, é de 1,0 mg/L. Neste contexto, a precipitação oxidativa com KMnO4, quando empregada para recuperação e remoção do manganês, se destaca como um processo promissor. Neste trabalho, a primeira etapa constou de um planejamento estatístico onde foi possível a avaliação da influência de parâmetros de processo e a modelagem empírica da precipitação oxidativa do Mn II em amostras preparadas em laboratório. Foram avaliados quatro parâmetros: a dose de KMnO4, o pH, o tempo de reação e a concentração da solução de KMnO4. Apenas a dose de KMnO4, o pH e a interação entre estes dois fatores apresentaram influência significativa sobre o processo de precipitação oxidativa do manganês. Na etapa de otimização, a análise do aspecto das superfícies de resposta, descritas por modelos matemáticos empíricos, permitiu avaliar as combinações entre o pH e a dose de KMnO4 que contribuem para uma maior eficiência do processo. Os melhores resultados foram obtidos para doses de KMnO4 de 1,63 mg KMnO4/mg Mn II em pH 3,0 e 1,54 mg KMnO4/mg Mn II em pH 5,0. As remoções de manganês observadas nestas condições foram 99,84% e 99,90% respectivamente, para uma concentração inicial de 100 mg/L. Posteriormente, o estudo cinético do processo utilizando soluções de Mn II preparadas em laboratório, mostrou que a precipitação do manganês com KMnO4 apresenta a vantagem de ser rápida. A concentração de Mn II decresceu exponencialmente atingindo limites inferiores a 1,0 mg/L em menos de 10 minutos de reação. A cinética da reação foi favorecida com a elevação do pH. Os precipitados formados apresentaram baixa cristalinidade com pequenas diferenças morfológicas em função do pH do meio, sendo a fase mineralógica encontrada a birnessita (MnO2), de acordo com espectroscopia RAMAN. Estas observações experimentais estão de acordo com os resultados da modelagem realizada com o programa PHREEQC, na qual a presença do óxido de manganês MnO2 foi confirmada nas fases birnessita, pirolusita e nsutita. Na etapa final, amostras de drenagem ácida oriundas de uma antiga mina de urânio desativada foram caracterizadas quimicamente e submetidas ao tratamento com KMnO4 em escala laboratorial. A caracterização das amostras mostrou que os parâmetros que estão fora da especificação segundo a legislação são o manganês, o fluoreto e também o pH. Além disso, as concentrações de cálcio, alumínio e sulfato são relativamente elevadas. O ensaios de precipitação oxidativa foram conduzidos em valores de pH 3,0, 5,0 e 7,0. Em pH 7,0 o processo mostrou-se mais eficiente, não apenas em relação a remoção de Mn II, que alcançou níveis de aproximadamente 99 %, mas também em termos da velocidade de reação, sendo o equilíbrio atingido em 10 min de reação. Verificou-se uma remoção mais significativa dos outros componentes como ferro, alumínio e urânio na etapa de ajuste do pH para 7,0 com NaOH. Os precipitados formados na etapa de oxidação não apresentaram cristalinidade, contudo foram identificadas as fases birnessita (MnO2), hausmanita (Mn3O4) e manganita (MnOOH), de acordo com espectroscopia RAMAN. Além do manganês, foram detectados nos precipitados: alumínio, cálcio, zinco, urânio, terras raras, oxigênio e flúor. A simulação com o PHREEQC permitiu a identificação das fases termodinamicamente possíveis em cada etapa do processo. Na etapa de ajuste de pH foram formadas, principalmente, fases contendo ferro, urânio, alumínio e o manganês. A etapa de adição do agente oxidante foi caracterizada por remoções de manganês nas fases birnessita (MnO2), bixbyita (Mn2O3), hausmanita (Mn3O4), manganita (MnOOH), nsutita (MnO2), pirolusita (MnO2) e cálcio na forma de fluorita (CaF2) / The manganese contamination present in acid mine drainage is outstanding as one of the main environmental issues experienced by the mining sector. This element has been frequently found in concentrations much higher than the allowed limit for discharge which is 1.0 mg/L according to Brazilian legislation, CONAMA No. 430. In this context, the oxidative precipitation by KMnO4, when employed to recover and remove manganese is a promising process. In this work, throughout a statistical design it was possible to assess the influence of process parameters as well as the empirical modeling of oxidative precipitation of Mn II in laboratory prepared samples. The experiments consisted of evaluating four parameters: the KMnO4 dose, pH, reaction time and concentration of KMnO4 solution. Only the dose of KMnO4, the pH and the interaction between these two factors have shown significant influence. In the optimization stage, by observing the aspect of the response surfaces, described by empirical mathematical models, it was possible to find out the combinations between pH and KMnO4 dose that could increase the process efficiency. The best results were obtained throughout trials conduct at pH 3.0 with KMnO4 ratio of 1.63 mg KMnO4/mg Mn II and at pH 5.0 with ratio of 1.54 mg KMnO4/mg Mn II. The manganese removals under these conditions were 99.84% and 99.90%, respectively. Subsequently, the kinetics study was carried out by using solutions of Mn II prepared in the laboratory. The results have shown that the precipitation of manganese by KMnO4 has the advantage of being fast. The concentration of Mn II decreases exponentially reaching the lower limit of 1.0 mg/L around 10 minutes of reaction. Additionally, the kinetics of the reaction is favored with increasing pH. The produced precipitates have low crystallinity and show slight morphologic differences according to the pH assessed. The main mineral phase identified by RAMAN spectroscopy was birnessite (MnO2). These experimental observations match with the modeling results performed withPHREEQC, in which the presence of manganese oxide MnO2 was identified as birnessite, pyrolusite and nsutita. In the final step, samples of acid mine drainage originated from one former and inactive uranium mine were chemically characterized and underwent with KMnO4 in bench scale. The samples characterization showed that manganese, fluoride and the pH are beyond limits set by legislation. Furthermore, the calcium, aluminum and sulphate are present in relatively high concentrations. The oxidative precipitation trials were carried out at pH 3.0, 5.0 and 7.0. At pH 7.0 the process was more efficient for the removal of Mn II, which accomplished levels of approximately 99%, and also in terms of reaction rate, the equilibrium was achieved within 10 min of reaction. Under the same condition i.e., at pH 7.0, there was an increase in the removal of other components such as iron, aluminum and uranium. The precipitates formed were not crystalline; nevertheless it was possible to identified the phases birnessite (MnO2), and possibly hausmanita (Mn3O4) and manganite (MnOOH) by RAMAN spectroscopy. Besides manganese, the species aluminum, calcium, zinc, uranium, rare earths, oxygen and fluorine were also detected in the precipitated. The simulation with PHREEQC enabled the identification of thermodynamically possible phases at each stage of the process. In the step of pH adjustment, essentially, phases containing iron, uranium, manganese and aluminum are formed. The adding of KMnO4 is characterized by manganese and calcium removal as birnessite (MnO2), bixbyite (Mn2O3), hausmaninte (Mn3O4), manganite (MnOOH), nsutite (MnO2), pyrolusite (MnO2) and fluorite (CaF2).

Proveniente das atividades de mineração, a drenagem ácida de minas (DAM) é uma solução aquosa caracterizada por valores de pH menores que 3 e diversidade de metais dissolvidos com concentrações que variam de 100 a 300mg.L-1, representa riscos ambientais, em especial, impactos hídricos, em conseqüência da solubilização e mobilização de metais pesados. A pesquisa por novos processos de tratamento de efluentes contaminados com metais tem focado sua atenção na capacidade que certos materiais biológicos têm de fixar íons metálicos. A biossorção é um processo vantajoso quando comparado aos tratamentos convencionais porque não requer custos de investimento e operação, é um processo rápido e pode ser seletivo, além disso, o metal pode ser recuperado e o biossorvente reutilizado. Rhodococcus opacus é uma bactéria, gram-positiva, não patogênica, de fácil aquisição que apresenta em sua parede celular compostos que lhe conferem hidrofobicidade, características que tornam esta espécie microbiana um potencial agente de sorção. O objetivo deste trabalho é avaliar a capacidade do Rhodococcus opacus como biossorvente destinado ao tratamento da drenagem ácida de minas proveniente da mineração de carvão. As características da superfície do microrganismo e os possíveis mecanismos de interação envolvidos na sorção dos metais pelo Rhodococcus opacus foram avaliados através da medida de potencial zeta, análise de espectroscopia de infravermelho e análise de imagens obtidas no icroscópio eletrônico de varredura (MEV). A porcentagem de metais presentes na composição das células de Rhodococcus opacus foi obtida através do ensaio de erda ao fogo e é de aproximadamente 1,8%. O equilíbrio do processo biossortivo em sistema multimetálico foi atingido em cerca de 1minuto, captando 48,2mg.g-¹ o que correspondo a aproximadamente 11,7% de remoção. O PIE da Rhodococcus opacus ocorreu em pH próximo a 2,6. / Originating from mining and mineral industry activities, the acid mine drainage (AMD) is an aqueous solution with pH lower than 3 and diversity of dissolved metals, with concentrations about 100 to 300mg.L-1, leads to serious environmental problems, specially on acquatic ecosystems, due to the solubilization of heavy metals. The search for new technologies on the treatment of effluents contaminated with metals is focused on some biological materials capacity of binding metallic ions. Treatment by biosorption is worthwhile when compared with conventional processes because it does not require high investiments, it is faster, metals can be recovered and biosorbent can be regenerated. Rhodococcus opacus is a gram-positive, nonpathogenic bacteria, that is easily obtained. Its hydrophobicity is due to compounds present in its surface. Such characteristics turn these microorganisms into a potential sorption agent. This paper aims to evaluate the Rhodococcus opacus capacity as a biosorbent in AMD treatment by batch experiments. The characteristics of the microorganism surface and the involved interaction mechanisms in the heavy metals sorption by Rhodococcus opacus, was evaluated based in the potential zeta measurements, infrared spectroscopy and electron microscopy scanning analysis. The metals percentage present in the composition of Rhodococcus opacus cells was obtained by loss on ignation technique, and was approximately 1.8%. The equilibrium of biosorptive process in the multi-metallic system was achieved at about 1 minute, uptake 48.2mg.g-1 corresponding to approximately 11.7% of removal. The Rhodococcus opacus IEP occurred at pH around 2.6.

Na região sul do Brasil, muito aterros sanitários encontram-se próximos a áreas de mineração de carvão, cujos rejeitos são ricos no mineral pirita (FeS2). Este trabalho teve como objetivo estudar o tratamento de lixiviado de aterro sanitário com coagulantes férricos e ferrosos produzidos a partir da oxidação da pirita em meio aquoso. O lixiviado de aterro sanitário foi coletado no Aterro do Município de Campo Bom no Vale do Rio dos Sinos – RS. Pesquisou-se o efeito da dosagem do coagulante e avaliou-se comparativamente o desempenho com coagulantes comerciais produzidos a partir da dissolução de sucata ferrosa em ácido sulfúrico. Os resultados obtidos demostraram que os coagulantes férricos são eficiente no tratamento por coagulação dos lixiviados em dosagens superiores a 1 g/L. Verificou-se também que os coagulantes ferrosos podem ser aplicados no tratamento do chorume pelo processo Fenton (H2O2/Fe). Foram realizados ensaios considerando diferentes misturas de chorume e DAM, com e sem a adição de H2O2. O efeito de coagulação, em ambos os casos, melhorou as características do efluente em termos de carga orgânica, metais pesados e nutrientes. Porém, quando foi adicionado o H2O2 (Reação de Fenton), o efluente final apresentou melhores resultados em relação a cor, COT (Carbono Orgânico Total), nutrientes e, principalmente, em termos de bactérias do grupo coliforme. Os resultados demonstraram que a drenagem ácida de minas, especialmente as mais concentradas e ricas em Fe+2, podem ser empregadas a baixo custo como fonte de ferro para a Reação de Fenton. Desta maneira, surgem novas tecnologias para o tratamento primário de chorume com o uso de coagulante férricos e ferrosos produzidos a partir da oxidação da pirita presente em rejeitos de carvão. / In southern Brazil, most landfills are close to coal mining areas, whose tailings are rich in the mineral pyrite (FeS2). This work aimed at studying the treatment of landfill leachate with ferrous and ferric coagulants produced from the oxidation of pyrite in aqueous media. The landfill leachate was collected in the landfill of the city of Campo Bom in the region of Vale do Rio dos Sinos – RS, Brazil. The effect of the dosage of coagulant was evaluated and compared performance with commercial coagulants produced from the dissolution of ferrous scrap in sulfuric acid was researched for this paper. The results showed that ferric coagulants are effective in the treatment of leachate by coagulation at dosages greater than 1g / L. It was also found that the ferrous coagulants can be applied in the treatment of leachate by Fenton process (H2O2/Fe). Researches have been performed considering different mixtures of manure and AMD (Acid Mine Drainages), with and without the addition of H2O2. The coagulation effect in both cases, improved the characteristics of the effluent in terms of organic load, heavy metals and nutrients. However, when H2O2 (Fenton reaction) was added, the wastewater showed better results for color, TOC (Total Organic Carbon), nutrients, and especially in terms of coliform bacteria. The results showed that acid mine drainage, especially the most concentrated and rich in Fe +2, can be employed at low cost as a source of iron for the Fenton reaction. Thus, there are new technologies for the primary treatment of manure with the use of ferrous and ferric coagulant produced from the oxidation of pyrite present in coal tailings.

Magister Scientiae - MSc (Dept. of Chemistry) / Fly ash and AMD samples were characterised by standard analytical methods for selection of the test materials. Active treatment by means of mixing fly ash with AMD in beakers and a large tank at pre-determined ratios have shown that fly ash is capable of neutralising AMD and increasing the pH beyond neutral values, which optimises the removal of heavy metals and ions. The trend was: the more fly ash added the quicker was the reaction time and higher the pH values achieved. Iron was reduced by as much 99 % in beaker scale experiments via Fe(OH)3 precipitation at pH values >4.0. A 99 % decrease in aluminium concentration was observed which was attributed to the precipitation of primarily gibbsite and various other mineral phases at pH values >5.5. As the pH increases, sulphate is adsorbed via Fe(OH)3 and gypsum precipitation at elevated pH. Sulphate attenuation with fly ash was excellent, achieving 98 % attenuation with beaker scale experiments and 1:1 fly ash:AMD ratio. Sulphate attenuation with fly ash was comparable to membrane and ion exchange systems and exceeded the performance of limestone treatment. Except for the larger volumes of fly ash needed to neutralise the AMD, fly ash proved to be a feasible and cost efficient alternative to limestone treatment. Fly ash produced competing results to limestone concerning acidity removal and sulphate attenuation. The comparison highlighted the advantages of utilising fly ash in comparison to limestone and demonstrated its cost effectiveness. The results of this study have shown that fly ash could be successfully applied for the neutralisation of acid mine drainage (AMD) and effectively attenuate the sulphate load in the treated water. The critical parameters to this technology are the variations of chemical composition and mineralogy of fly ash, which could influence the pH, contact time of the neutralisation reaction, and the same is true if the AMD quality varies. / South Africa

Masters of Science / Over the years, South Africa has produced over 468 million tons of mine waste yearly, in which gold mining waste accounted for 221 million tons (47%) of all mine waste produced, making it the largest, single source of waste and pollution. The exposure of these mine wastes such as tailings dams, waste rocks to oxidation and leaching has been the source of heavy metal release into the environment. This study assessed the magnitude of possibly leachable metals, its distribution and associations and predicted the AMD load discharge over time, from Mogale’s tailings dam into the environs in Randfontein area, Witwatersrand Basin, South Africa. Fifty-one tailings dam samples were analysed for their mineral and multi-elements contents. Petrography studies was done by X-Ray Diffraction (XRD) technique to determine the mineralogical composition. X-ray fluorescence (XRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) techniques were used to determine the multi-elements content in the tailings dam samples. The dataset were evaluated using multivariate statistics, Geographical Information Systems (GIS) and geochemical mass balance techniques. From the results, the tailings dam lithology was grouped into four distinct layers. The uppermost oxidized layer is siliceous and contains the highest SiO2 (87.32%) contents, which is with the lowest contents in Tot/S, U, As, Zn, Ni, Co, and Cu. A downward decrease in SiO2 (76.39%) contents occurs, coupled by an increase in Fe2O3, Tot/S, U, As, Zn, Ni, Co, and Cu, reaching maximum contents in layer 3. Layer 4 is the least weathered horizon. The cluster analysis grouped the samples into four sub-clusters based on the variation in SiO2 and Al2O3 contents. Factor analysis (83.542% total data variance) related the four controlling factors of element distribution to the occurrence in ore elements (sulphides), silicates, mining additives and refractory minerals. Elements of the same origin show a similar concentration trend down hole in the GIS interpolation analysis. The geochemical mass balance showed variable gain and loss of oxides and trace elements within each layer. Based on the variation patterns of the Tot/S contents and other mobile elements, about 0.164kg/tonne/yr(±0.02) of the tailings materials are leached yearly. Layer 1 is the most altered. This assessment and prediction study therefore gives an insight to the geochemical behaviour of an abandoned tailings dam, highlighting its extent of oxidation. However, the interaction between the oxidized zone and transition zone should be given more attention, to determine the actual extent of damage.

For decades, researchers have been working to better understand the effects of acid and metal toxicity to aquatic organisms and to develop ways to effectively mitigate these detrimental effects. Acid mine drainage (AMD) causes environmental pollution that affects many countries having historic or current mining industries. Both surface and underground mining have the potential to create AMD and therefore adversely affect the local and adjacent environments. Through malignant mining and farming practices, damming rivers and the changing climate, surface freshwater resources are rapidly being reduced in Australia. Mine pit lakes offer a large freshwater resource that if managed correctly may sustain significant environmental, social and economic benefits from selected end uses for the future. However, assessment of mine pit lakes needs to be achieved to validate end use options. The Collie Basin located in the southwest of Western Australia is a coal mining area with many abandoned open cast mines (OCM). Some of these OCM have filled with water forming mine pit lakes that are affected by AMD. The result is large freshwater bodies with moderate to high concentrations of metals and a low pH. High concentration of metals combined with low pH is of environmental concern to both the aquatic and terrestrial ecosystem. Nevertheless, remediation techniques for AMD are available and applicable to these acidic lakes. However, the lakes in the Collie Basin are low in sulphatic compounds, therefore, restricting the use of the most common remediation treatment of bioremediation with sulphate reducing bacteria. Three remediation treatments were assessed for there efficacy in toxicity amelioration to three mine pit lakes. The treatments assessed were Limestone addition, phosphorus addition and a Rapid Catalytic Oxidation (RCO) treatment. / Toxicity assessment was achieved by means of comparing physico-chemical data to guideline trigger values and biological assessment. Biological assessment was achieved with three commonly used but ecologically and geographically relevant species. The bioassay species were the alga Chlorella protothecoides, the crustacean Ceriodaphnia cf dubia and the protozoa Tetrahymena thermophila. Aquaculture is being trialled adjacent to one of the pit lakes in limestone treated mine pit lake water. Therefore, the aquaculture fish species Bidyanus bidyanus early life stages were also used to assess residual toxicity from treated mine pit lake water. Limestone remediation of pit lake water demonstrated good reduction of dissolved metal concentrations with the exception of Zn and the ability to increase pH to circum-neutral. Biological assessment of limestone treated pit lake water showed that toxicity was removed to the three bioassay species and to the aquaculture species B. bidyanus early life stages. A larger field- scale mesocosm experiment with limestone treatment in situ is recommended. Assessment of the mesocosm experiment with biological and chemical analysis will confirm the efficacy of this treatment for full scale use.

This study covers the following aspects of mine water management at the Clarence Colliery, located at the headwaters of the Wollangambe River, N.S.W. The Wollangambe River flows through the World Heritage listed areas of the Blue Mountains and Wollemi National Parks. 1. Quantification of the impact of discharge of treated mine water on the Wollangambe River, through analysis of sediment metal concentrations. 2. Investigation of the possible sources and causes of acid mine drainage within the mine. 3. Review of the current treatment process employed at the mine, as well as a review of other possible treatment options for avoidance or treatment of acid mine drainage. 4. Recommendation of a strategy for improving the process of mine water management at the colliery. The study reveals problems discovered from the investigation and describes the findings and recommendations. / Master of Engineering (Hons.)

<p>This study evaluated SO4 2- removal from circumneutral mine water (CMW) collected from Middleburg coal mine using coal FA collected from Hendrina power station. The following parameters were investigated: the effect of the amount of FA, the effect of the final pH achieved during treatment, the effect of the initial pH of the mine water and the effect of Fe and Al on SO4 2- removal from mine water. The precipitation of ettringite at alkaline pH was evaluated to further reduce the SO4 2- concentration to below the DWAF limit for potable water. Removal of SO4 2- from mine water was found to be dependent on: the final pH achieved during treatment, the amount of FA used to treat the mine water and the presence of Fe and Al in the mine water. Treatment of CMW using different CMW:FA ratios / 5:1, 4:1, 3:1, and 2:1 resulted in 55, 60, 70 and 71 % SO4 2- removal respectively. Treatment of CMW to pH 8.98, 9.88, 10.21, 10.96, 11.77 and 12.35 resulted in 6, 19, 37, 45, 63 and 71 % SO4 2- removal respectively. When the CMW was modified by adding Fe and Al by mixing with Navigation coal mine AMD and treated to pH 10, 93 % SO4 2- removal was observed. Further studies were done to evaluate the effects of Fe and Al separately. Treatment of simulated Fe containing AMD (Fe-AMD) to pH 9.54, 10.2, 11.8, and 12.1 resulted in 47, 52, 65, and 68 % SO4 2- removal respectively. When Al containing AMD was treated to pH 9.46, 10.3, 11.5 and 12 percentage SO4 2- removal of 39, 51, 55 and 67 % was observed respectively.</p>

<p>Fly ash and AMD samples were characterised by standard analytical methods for selection of the test materials. Active treatment by means of mixing fly ash with AMD in beakers and a large tank at pre-determined ratios have shown that fly ash is capable of neutralising AMD and increasing the pH beyond neutral values, which optimises the removal of heavy metals and ions. The trend was: the more fly ash added the quicker was the reaction time and higher the pH values achieved. Iron was reduced by as much 99 % in beaker scale experiments via Fe(OH)3 precipitation at pH values &gt / 4.0. A 99 % decrease in aluminium concentration was observed which was attributed to the precipitation of primarily gibbsite and various other mineral phases at pH values &gt / 5.5. As the pH increases, sulphate is adsorbed via Fe(OH)3 and gypsum precipitation at elevated pH. Sulphate attenuation with fly ash was excellent, achieving 98 % attenuation with beaker scale experiments and 1:1 fly ash:AMD ratio. Sulphate attenuation with fly ash was comparable to membrane and ion exchange systems and exceeded the performance of limestone treatment. Except for the larger volumes of fly ash needed to neutralise the AMD, fly ash proved to be a feasible and cost efficient alternative to limestone treatment. Fly ash produced competing results to limestone concerning acidity removal and sulphate attenuation. The comparison highlighted the advantages of utilising fly ash in comparison to limestone and demonstrated its cost effectiveness. The results of this study have shown that fly ash could be successfully applied for the neutralisation of acid mine drainage (AMD) and effectively attenuate the sulphate load in the treated water. The critical parameters to this technology are the variations of chemical composition and mineralogy of fly ash, which could influence the pH, contact time of the neutralisation reaction, and the same is true if the AMD quality varies.</p>