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Integrated mineral technologies for more sustainable raw material supply

Periodic Reporting for period 2 - ITERAMS (Integrated mineral technologies for more sustainable raw material supply)

Berichtszeitraum: 2018-12-01 bis 2020-11-30

The ITERAMS project “Integrated Mineral Technologies for More Sustainable Raw Material Supply” reinvented water and waste in mining. The new methods developed in the project offer the EU the potential to be in the forefront with regard to minimal waste, minimal energy and minimal water consumption in the mining sector.

Mining has been and is still a significant user of land space and water. One of the major environmental issues in processing the ore to concentrates is the waste stream, which can reach over 90% of the total mass. The ITERAMS project targeted significantly reducing water consumption by circulating process waters and reducing the amount of tailings waste through valorisation of the mineral matrix. Water circulation reduces water consumption at mine sites and the need to dispose of large quantities of wastewater in surrounding areas. To achieve this, the project focused on the complete isolation of process waters from the adjacent water systems. This required development of new methods for optimizing and controlling water qualities at each process step. As a bonus, it also facilitates the recovery of additional valuable constituents. The closure of water cycles inevitably increases the process disturbance, temperature and instability and results in a dynamic situation. The completely closed water cycles can be realized only if the tailings can be filtered and stacked dry.

The geopolymer technology has long been recognized as providing the potential for immobilization of hazardous components in the structure and thus providing a safe method for utilizing mine tailings in value added applications. The use of geopolymers as water- and oxygen-tight covers on the deposited tailings, as hardening mine fill or as sellable products was demonstrated in the project.
Water technologies, on-line sensors, ore sorting and new approaches to the valorization of tailings have been developed and piloted at mine sites in Finland, Portugal and South Africa. These campaigns have demonstrated that new sensors can reliably monitor contaminants of interest and water can be cleaned efficiently and made ‘fit-for-purpose’. Real value has been shown with ore sorting, with rapid adoption in the mining industry expected. Dry tailings have been transformed into a cement like material in a process called geopolymerisation. We have developed a protocol on closed water loops with clear recommendations for all stakeholders, building on the knowledge created during the project.

ITERAMS brings substantial advancements in water management for closing the water cycle in mines. This advancement refers to progress on individual technologies (DAF, ion exchange, filtration, among others) but also in a smart and efficient combinations of the technologies. The different validation mine sites in the project confirmed that there is no “one ITERAMS solution” for closing the water cycle, consisting of a certain pattern of technologies that are interconnected in one approved set, but rather ITERAMS is offering a solution portfolio, which has been tested and validated in small scale. This solution portfolio should be adapted to the specific requirements of a mine site and its operating mode. Sensors are an essential element in a well-managed water circulation system. In ITERAMS, new sensors for measuring ion concentration in water streams have developed, based on Ion-Selective Electrodes (ISE). Conceptually, a water treatment protocol has been developed, to guide interested users towards a promising and effective water treatment design, for a mine site.

Further, ITERAMS achieved a better understanding of conditions that are suitable for creating geopolymers from tailings obtained from ore processing and was able to successfully create these geopolymers and validate
the models and concepts in relevant tests. It was no surprise to see that the initial properties of tailings vary tremendously from mine to mine, and that a “one fits all” approach and recipe for obtaining geopolymers is out of the question.

Not the least, a sustainability assessment for mine sites has been developed and successfully applied, that is at the same time able to capture the various sustainability effects of a mine operation, on-site and to local
communities, as well as through the supply chain and life cycle, for environmental, social, and economic impacts. For validation sites with very different conditions, a complete sustainability model has been created. The approach includes a procedure of how to understand and evaluate a social license (SLO) to operate for a mine site, and aspects affecting this SLO.

With ITERAMS results, it is thus possible to sort the ore, to close the water cycle in a mine site, to produce, depending especially on geological conditions, geopolymers from residues of the treatment of the circulated water, to assess the sustainability of the operations, and to guide and steer the operation of the mine towards sustainability.
The ITERAMS portfolio offers different technologies for (1) water treatment, (2) geopolymer creation to be used as cover for waste (tailings and waste rocks) or as backfill material; (3) water quality monitoring through sensors; (4) ore sorting; (5) a methodology for an integrated life cycle sustainability assessment of mining technologies; and (6) a protocol for water management. Therefore, results included both technical experiments and findings as well as environmental, social, and economic sustainability -qualitative and quantitative- evaluations. The methodological developments can also be considered as a core outcome of the ITERAMS project.

The project will maintain Europe at the forefront in the fields of efficient water circulation and sustainable tailings utilization. The project developed new holistic water and waste concepts and systems, which result in higher technical, economic and environmental performance in raw materials production. The developed ITERAMS water and waste efficient concepts were jointly validated by industrial and research partners at their mine sites. The ITERAMS vision is that our new knowledge and technologies will enable (i) significantly more efficient water recycling at the mining sites in Europe and globally, (ii) valorisation of the solid waste residues will bring cost savings and added income streams for especially small mines and (iii) minimisation of the overall environmental footprint to improve the mining industry´s performance and as a consequence the image. We also anticipate that ITERAMS solutions will influence on the total lifecycle of the mining operation, as they provide input to project planning and operational phases as well as to the closure and rehabilitation.
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