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The European mining industry is an active sector. Mining operations disturb large volumes of land and produce huge quantities of waste. The tailings dams of the mining industry occupy large areas representing a huge cost in terms of operation/maintenance, health, safety, environment and economy. This paper is an overview of the possible sustainable waste management strategies that are targeted on the reuse of residues as secondary resources. Therefore, it is focused on restoring mine tailings as inert materials to be used as technosols in the green infrastructures sector (e.g., green roofs, urban green spaces). Technosols are man-made soils, intentionally “constructed” or modified to meet specific needs like waste management and storage, support of industrial activities, infrastructures foundations, or green infrastructures. Technosols play an important role in a wide variety of ecosystems, being essential for designing sustainable rehabilitation techniques, city planning, and land use management. To make advantage of the land in former mining areas and speed up their ecological restoration, some studies proposed the increase of nutrients in affected soils through amendments such as compost, biochar, different organic wastes or undegraded soils. This review aims i) to investigate the efficiency of organic amendments in increasing the resilience of former mining sites and ii) to provide insight in functional indicators that can be used to assess the ecological compatibility of reconstructed technosols. © 2021 International Multidisciplinary Scientific Geoconference. All rights reserved.

Abstract

Critical metals are those metals considered to be of fundamental importance for high-level industrial development. The definition of criticality derives, on the one hand, from the concentration of raw material sources in certain geographic areas, and on the other hand, the impossibility of replacing them with similar materials in the production processes. For a good management of raw material resources in general, and critical metals in particular, it is necessary to establish an eco-efficient strategy, to reinvent the sources of raw materials. The most recent European Commission reports on economy include legislative proposals on waste, aiming long-term measures to reduce landfilling on the one hand and to increase the recycling and reuse rate. Thus, innovative biotechnological methods for recovery of critical metals from mine waste (tailing, dumps, and ponds) or industrial process residues (e.g. waste waters, industrial waste) have been developed. Microbial leaching and microorganisms’ involvement in the control of redox reaction and metal adsorption could enhance the recovery of various amounts of critical metals from diverse secondary materials. Another research direction is the so-called urban mining, which represents the recovery of critical metals from waste electronic and electric equipment. This paper presents success stories in the current context of bioeconomy development regarding proper resource management by applying eco-efficiency principles. © 2018, International Multidisciplinary Scientific Geoconference. All rights reserved.

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According to the European Commission, critical raw materials are defined as ‘those which display a particularly high risk of supply shortage in the next 10 years and which are particularly important for the value chain’. Therefore, when considering a raw material criticality, two main parameters are taken into account: its economic importance and supply risk. Technologies which a decade ago were considered high tech became current today, and raw materials once considered as minor, have gained importance. Particularly, the industry demand for critical metals is growing, because they are used in modern and high-tech frontier technologies that include low carbon systems. Critical metals are indispensable in many industrial applications, in construction, aviation, photovoltaic cells, cell phones, renewable energy, LED Monitors, computers, automotive-hybrid and electric vehicles. Most of them are obtained from primary sources which are rapidly decreasing as a result of urbanization, increased standards of living and population explosion. Recently, political, economic and research initiatives are undertaken to mitigate the risks associated with critical metals supply. These actions resulted from the price volatility, the extraction costs and from concerns regarding the future availability of critical materials in general, and critical metals, also. Development of new strategies to source critical metals towards setting up of innovative mining technologies is the key for supporting the EU industry. This can be achieved by recovery of these metals from mine tailings or by recycling from waste electronic equipment. Several reports indicated as a possible solution the use of microorganisms with recovery potential in bioleaching and bioaccumulation of critical metals. Therefore, further research is needed for the identification of microbial consortia with practical application in the design of biotechnological processes for the extraction of critical metals. © SGEM2017. All rights reserved.

Abstract

Developing innovative biotechnology for obtaining new resources of high tech critical metals is strongly influenced by the need to reduce the potential risk of shortages, to support the development of industry at European level. To set up these new technologies is essential to isolate strains with high potential in bioleaching of ore, tailings and mine wastes and bioaccumulation of high tech critical metals. Microorganisms are capable of mediating metal and mineral bioprecipitation. In this paper are presented preliminary studies performed for the isolation of strains existing in mining residues containing high tech critical metals. Were used samples collected from various depths in an area of mining wastes containing high tech critical metals. The samples were fine grounded and the powder was washed with sterile saline water. Exact quantities of samples were dispersed in sterile saline water, shaken for a period of 60 minutes, diluted and plated in triplicate on selective agar. After several steps were isolated 3 strains of gram negative bacteria. © 2016 Vasile Goldis University Press.

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