Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments

Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments. This document summarizes the literature of mining pit lakes (through 2007), with a particular focus on issues that are likely to be of special relevance to the creation and management of pit lakes in northern climates. Pit lakes are simply waterbodies formed by filling the open pit left upon the completion of mining operations with water. Like natural lakes, mining pit lakes display a huge diversity in each of these subject areas. However, pit lakes are young and therefore are typically in a non-equilibrium state with respect to their rate of filling, water quality, and biology. Separate sections deal with different aspects of pit lakes, including their morphometry, geology, hydrogeology, geochemistry, and biology. Depending on the type and location of the mine, there may be opportunities to enhance the recreational or ecological benefits of a given pit lake, for example, by re-landscaping and re-vegetating the shoreline, by adding engineered habitat for aquatic life, and maintaining water quality. The creation of a pit lake may be a regulatory requirement to mitigate environmental impacts from mining operations, and/or be included as part of a closure and reclamation plan. Based on published case studies of pit lakes, large-scale bio-engineering projects have had mixed success. A common consensus is that manipulation of pit lake chemistry is difficult, expensive, and takes many years to achieve remediation goals. For this reason, it is prudent to take steps throughout mine operation to reduce the likelihood of future water quality problems upon closure. Also, it makes sense to engineer the lake in such a way that it will achieve its maximal end-use potential, whether it be permanent and safe storage of mine waste, habitat for aquatic life, recreation, or water supply

Environmental challenges related to cyanidation in Central American gold mining; the remance mine (Panama)

Mine tailings are a potential source of environmental pollution because they typically contain potentially toxic elements (PTEs) and the residue of chemical compounds used during extraction processes. The Remance gold mine (NW Panama) is a decommissioned mine with mining activity records dating from the 1800s and several periods of abandonment. Very little remediation work has been performed, and waste is exposed to climatic conditions. This study aimed to evaluate the PTEs and cyanide contents in mine waste after mining operations ceased some 20 years ago, and to evaluate the degree of pollution and the environmental risks they pose with the use of the Pollution Load Index (PLI) and the Ecological Risk Index (RI). Although the total cyanide (T-CN) concentration (1.4–1.9 mg kg−1) found in most of the study area falls within the limits of gold mining tailing values for American sites (1.5–23 mg kg−1), it is worth noting that the values of the tailings of the last used mining operation exceed it (25.2–518 mg kg−1) and persist at the site. The PLI and RI suggest that the tailings from the mine and mine gallery sediments represent a source of pollution for soils and surrounding areas given their high content of PTEs (As, Cu, Sb, Hg) and T-CN, which pose serious ecological risks for biota. Therefore, it is necessary to draw up a remediation plan for this area

A Model for the Operationalization and Implementation of the Precautionary Principle: Cyanide-Leach Technology and Gold Mining Development

Mining development provides tremendous amount of long-term environmental and community degradation all over the world. Often, local communities bear the burden. This article demonstrates how the Bergama environmental network has utilized international environmental treaties with a focus on precautionary principle in order to halt the cyanide-leach Ovacik gold mine project in Turkey. The network has not only operated under the principle of precaution, but it has also defined and illustrated how the precautionary principle could be operationalized and implemented in practice in mining industry. By doing so, the Bergama environmental network developed a model for the operationalization and implementation of the precautionary principle in mining sector. In contrast to risk assessment that focus on the question of what level of contamination is safe, the precautionary approach focus on the question of how to reduce or eliminate the hazards and considers all the possible means of achieving that goal---including forgoing the proposed activity. This network has been promoting precautionary principle instead of risk assessment in mining nationwide. This model can be utilized by other communities dealing with mining developments in order to make the companies and their states to adopt and implement the precautionary principle. This article is based on a larger research project that has been taking place since 2002 on Ovacik gold mine development in Bergama. It relies on data that comes from interviews, focus group discussions with local community residents and field notes as well as books and documents prepared by the network and local newspapers that covered the case extensively

The treatment of cyanidation tailings using ion exchange resin

This thesis explores the behaviour of metal cyanide complexes under oxidative acid conditions in ion exchange systems, with the objective of developing an ion exchange based process for the treatment of gold cyanidation tailings. The novel cyanide detoxification process developed from this study employs strong base ion exchange resins to extract cyanide from tailings. Variations in the stability of cyanide complexes are exploited to concentrate, recover, or destroy cyanide species loaded on the resin, through the use of an oxidative acid eluent containing H2O2 and H2SO4. This eluent removes all base metal cyanide complexes from strong base resins, while regenerating the resin. The spent eluent, containing the base metals recovered from the tailings, can be used as a source of such base metals. Copper can be recovered separately from other base metals if necessary. Low levels of precious metals present in the tailings are accumulated on the resin as the ion exchange bed is cycled between loading and elution stages. They can be recovered economically, so as to offset the cost of the tailings detoxification. Cyanide is initially concentrated as an alkaline solution, which can be detoxified within the process or recovered for recycling. This process was successfully tested at pilot scale by treating approximately 14,000 m3 of cyanide contaminated tailings solution, over 14 loading/elution cycles on a standard strong base ion exchange resin bed. This treatment reduced the total cyanide concentration of the contaminated solution from approximately 50 mg/L to an average of 1.5 mg/L. The reagent cost was approximately ADD 0.50 per m3 of treated liquor. When the resin was repeatedly loaded with mixed metal cyanide species and eluted with the oxidative acid eluent, a gradual deterioration of the ion exchange resin performance was noted. The reduction of net operating capacity of the columns due to resin deterioration was in the order of 1-3% per loading/elution cycle. The oxidation of resin catalysed by copper, the precipitation of metal hexacyanoferrates on the resin and the oxidation of Au(CN)2- to Au(CN)4- were identified as possible factors giving rise to the reduction of resin loading capacity

Best Available Techniques (BAT) Reference Document for the Management of Waste from Extractive Industries in accordance with Directive 2006/21/EC

This document, Best Available Techniques Reference Document for the Management of Waste from Extractive Industries, in accordance with Directive 2006/21/EC, abbreviated as MWEI BREF, is a review of the Reference Document for Management of Tailings and Waste-Rock in Mining Activities (MTWR BREF). This review is the result of an exchange of information between experts from EU Member States, industries concerned, non-governmental organisations promoting environmental protection and the European Commission. The reviewed document presents up-dated data and information on the management of waste from extractive industries, including information on BAT, associated monitoring, and developments in them. It is published by the European Commission pursuant Article 21(3) of Directive 2006/21/EC on the management of waste from extractive industries. This document presents data and information on the following: - General information and key figures on extractive industries in Europe, extractive waste generation, extractive waste facilities and key environmental issues (Chapter 1). - Applied processes and techniques for the management of extractive waste (Chapter 2). - Emission and consumption levels resulting from the management of extractive waste (Chapter 3). - Techniques to consider in the determination of Best Available Techniques (Chapter 4). This includes generic management and waste hierarchy techniques, risk-specific techniques to ensure safety, techniques for the prevention or minimisation of water status deterioration, techniques for the prevention or minimisation of air and soil pollution and other risk-specific techniques. - Best available techniques conclusions (Chapter 5). - Emerging techniques (Chapter 6). This includes techniques that were reported at different levels of technology readiness. - Remarks and recommendations for future work (Chapter 7).JRC.B.5-Circular Economy and Industrial Leadershi

Characterization and modeling of mercury speciation in industrially polluted areas due to energy production and mineral processing in south africa

Coal combustion is recognized as the primary source of anthropogenic mercury emission in South Africa followed by gold mining. Coal is also known to contain trace concentrations of mercury which is released to the environment during coal mining, beneficiation or combustion. Therefore, determining the mercury speciation in coal is of importance in order to understand its behavior and fate in the environment. Mercury was also used, at a large extent, in the Witwatersrand Basin (South Africa) for gold recoveries until 1915 and is still used in illegal artisanal mining. Consequences of these activities are the release of mercury to the environment. Nowadays, gold (and uranium) is also recovered through the reprocessing of old waste dumps increasing the concern related to mercury pollution. While much effort has been put in the northern hemisphere to understand and control problems related to anthropogenic mercury release and its fate to the ecosystem, risk assessment of mercury pollution in South Africa was based, until very recently, on total element concentrations only or on non systematic fragmental studies. It is necessary to evaluate mercury speciation under the country’s semi arid conditions, which are different to environmental conditions that exist in the northern hemisphere, and characterize potential sources, pathways, receptors and sinks in order to implement mitigation strategies and minimize risk. In this study, analytical methods and procedures have been developed and/or optimized for the determination of total mercury and the speciation of inorganic and organic forms of mercury in different sample matrices such as air, coal, sediment, water and biota. The development of an efficient and cost effective method for total gaseous mercury (TGM) determination was achieved using nano-gold supported metal oxide (1% wt Au) sorbents and cold vapor atomic fluorescence spectrometry (CV-AFS). Analytical figures of merit and TGM concentrations obtained when using Au/TiO2, as a mercury trap, were similar to those obtained with traditional sorbents. The combination of isotope dilution with the hyphenated gas chromatography-inductively coupled plasma mass spectrometry (ID GC-ICP-MS) was also achieved and used successfully for the speciation analysis of mercury in solid, liquid and biological samples. The developed, or optimized, methodologies were used to estimate the average mercury content and characterize the speciation of mercury in South African coals, and also to study the speciation of mercury in selected South African environmental compartments impacted by gold mining activities. The obtained average mercury content in coals collected from the Highveld and Waterberg coalfields (0.20 ± 0.03 mg kg-1) was close to the reported United States Geological Survey (USGS) average for South African coals. Speciated isotope dilution analyses and sequential extraction procedures revealed the occurrence of elemental mercury, inorganic and organo-mercury species, and also the association of mercury mainly to organic compounds and pyrite. The environmental pollution assessment was conducted within the Witwatersrand Basin, at four gold mining sites selected mainly for their mining history and from geophysical information obtained through satellite images. This study showed a relatively important pollution in three of the four sites, namely the Vaal River west site near Klerksdorp, the West Wits site near Carletonville (both in the North-West Province) and the Randfontein site in the West Rand (Gauteng Province). Only one site, the closed Rietfontein landfill site in the East Rand (Gauteng Province) was found to be not impacted by mercury pollution. The methylation of mercury was characterized in all sites and factors governing the mercury methylation process at the different study sites were also investigated. Geochemical models were also used to explain the distribution, transport and fate of mercury in the study systems

Specifically Adsorbed Ions in Hematite Flotation

Specifically adsorbed ions, such as calcium and magnesium in iron ore flotation, are ions that can chemically bind with the mineral surfaces and alter the surface properties. Calcium and magnesium are unavoidable in process water and their concentrations are increasing due to water recirculation and reagent additions. These ions are detrimental to the flotation process. Calcium has always been the main focus in research, yet we found that magnesium is more detrimental in flotation due to its smaller atomic size. Starch adsorption in iron ore flotation is key for the effective depression of hematite. It has been determined by flotation, zeta potential, and settling tests, that increasing calcium concentrations promote starch adsorption and reduce entrainment of hematite, whereas increasing magnesium concentrations greatly reduce the selectivity overall by promoting the adsorption of starch to everything in the slurry and resulting in lower selectivity

Recovery of mining residues for eco-efficient mortar production

Raw materials are essential for human well-being, although their production, consumption and end-oflife are causing increasing environmental burdens. The Panasqueira mine has been operating for more than one century, being the main threat to its activity and for the surrounding ecosystem the disposal of significant amounts of old mining residues that contain substances of environmental concern. On the other hand, tungsten, considered a critical raw material, can be recovered from Panasqueira mining resources. In the construction sector, cement is one of the main contributors for greenhouse gas emissions and is the main binder used in mortar and concrete production. Hence, a partial replacement of this binder by secondary mining resources may bring economic, social, technical and environmental benefits. Efficient technologies to remove and recover elements from environmental matrices may promote safe storage and reuse. The electrodialytic (ED) treatment has demonstrated successful results on the removal of inorganic and/or organic contaminants from a wide range of resources. Thus, to address the challenges in climate change and environmental degradation issues, in both mining and construction sectors, the present work aimed at assessing the feasibility of applying the ED technology to mining residues for (1) the recovery of critical raw materials and the hydrogen that is inherently produced; (2) the removal of harmful compounds; (3) the production of a suitable matrix for further reuse in cementitious construction materials, and (4) the minimization of environmental impacts in the materials life cycle. The main results of the work developed demonstrated that the reuse of mining residues can decrease the consumption of primary resources and promote improvements in the sustainability of the industries involved, without high investments. Through the ED treatment, tungsten could be recovered in 22%, while the removal of arsenic may achieve 63%. The hydrogen produced can be recovered with 74% of purity. The production of cement-based mortars, replacing cement by treated mining residues, revealed similar performances to conventional mortars. Although a higher cement substitution percentage (50% volume) have caused some deterioration in mechanical resistance, the mortars produced demonstrated compatibility with current applications, as bedding mortars and fired brick masonry walls. The life cycle analysis also proved that the mortars produced allow impact mitigation in several environmental categories, namely in global warming potential, supporting the circular economy of sustainable construction products.As matérias-primas são fundamentais para o bem-estar humano, embora a sua exploração, consumo e fim de vida causem crescentes problemas ambientais. As minas da Panasqueira encontram-se em funcionamento há mais de um século, correspondendo a deposição de grandes quantidades de resíduos mineiros antigos, que contêm substâncias de preocupação ambiental, uma ameaça à sua atividade e ao ecossistema envolvente. Por outro lado, o tungsténio, considerado como matéria-prima essencial, pode ser recuperado dos recursos mineiros da Panasqueira. No setor da construção, o cimento é um dos principais responsáveis pelas emissões de gases com efeito de estufa, e o principal ligante utilizado na produção de argamassas e betões. Neste caso, a substituição parcial deste ligante por recursos mineiros secundários pode trazer benefícios económicos, sociais, técnicos e ambientais. Tecnologias eficientes para remover e recuperar elementos de matrizes ambientais podem promover um armazenamento e reutilização seguros. O tratamento eletrodialítico (ED) tem demonstrado resultados promissores na remoção de contaminantes inorgânicos e/ou orgânicos de uma ampla gama de recursos. Assim, para enfrentar os desafios das alterações climáticas e as questões de degradação ambiental no setor mineiro e da construção, o presente trabalho teve como objetivo avaliar a viabilidade da aplicação da tecnologia ED a resíduos de minas para (1) recuperação de matérias-primas essenciais e do hidrogénio que é inerentemente produzido; (2) remoção de compostos perigosos; (3) produção de uma matriz adequada para posterior reutilização em materiais de construção cimentícios e (4) minimização dos impactes ambientais no ciclo de vida dos materiais. Os principais resultados do trabalho desenvolvido demonstraram que a reutilização de resíduos de minas pode diminuir o consumo de recursos primários e promover melhorias na sustentabilidade das indústrias envolvidas, sem investimentos elevados. Através do tratamento ED, o tungsténio pode ser recuperado em 22%, enquanto a remoção de arsénio pode atingir os 63%. O hidrogénio produzido pode ser recuperado com 74% de pureza. A produção de argamassas com a substituição parcial do cimento por resíduos de minas tratados revelou desempenhos semelhantes às argamassas convencionais. Embora uma maior percentagem de substituição de cimento (50% volume) tenha provocado algum deterioramento nas resistências mecânicas, as argamassas produzidas demonstraram compatibilidade com aplicações atuais, como argamassas de assentamento e paredes de alvenaria de tijolo. A análise de ciclo de vida provou ainda que as argamassas produzidas permitem mitigar impactes em diversas categorias ambientais, nomeadamente no potencial de aquecimento global, apoiando a economia circular de produtos de construção sustentáveis

Proceedings of the 3rd IAGC International Conference: Water-Rock Interaction - 18 & Applied Isotope Geochemistry - 15. Cagliari, Italy, 16-21 June 2025

The third IAGC International Conference, held in Cagliari (Sardinia, Italy) in June 16-21, 2025, was widely attended by researchers from around the world. This resulted in the present volume of proceedings containing as many as 308 abstracts, both short and extended, distributed among 22 sessions in addition to the plenary sessions. The subjects covered in the abstracts span numerous topics in geochemistry, from low to high temperature, from frozen to hydrothermal systems, and natural and manmade environments. The conference was hosted by the Department of Chemical and Geological Sciences at the University of Cagliari (UNICA)

Industrial Waste

This book is intended to fulfil the need for state-of-the-art development on the industrial wastes from different types of industries. Most of the chapters are based upon the ongoing research, how the different types of wastes are most efficiently treated and minimized, technologies of wastes control and abatement, and how they are released to the environment and their associated impact. A few chapters provide updated review summarizing the status and prospects of industrial waste problems from different perspectives. The book is comprehensive and not limited to a partial discussion of industrial waste, so the readers are acquainted with the latest information and development in the area, where different aspects are considered. The user can find both introductory material and more specific material based on interests and problems. For additional questions or comments, the users are encouraged to contact the authors