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Integrated mineral technologies for more sustainable raw material supply

Periodic Reporting for period 1 - ITERAMS (Integrated mineral technologies for more sustainable raw material supply)

Reporting period: 2017-06-01 to 2018-11-30

The ITERAMS project “Integrated Mineral Technologies for More Sustainable Raw Material Supply” is reinventing water and waste in mining. The new methods developed in the project will 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 targets 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 focuses on the complete isolation of process waters from the adjacent water systems. This will require development of new methods for optimizing and controlling water qualities at each process step. As a bonus, it will also facilitate the recovery of additional valuable constituents. The closure of water cycles will inevitably increase the process disturbance, temperature and instability and result in a dynamic situation that has so far never been worked on. 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 will be demonstrated in the project. To this end, the tailings streams will be modified for their easier geopolymerisation.
The project started approximately 1,5 years ago. Water and tailings samples have been collected and analysed at the mines in Finland, Portugal, South Africa and Chile. WP1 (Property Modification for ore and rock beneficiation) and WP2 (Geopolymer products out of waste rock and tailings) were responsible for the sampling and analytics of solid samples, whereas WP3 (Closed water circulation) organized water sampling. Water sampling was done in summer and winter to demonstrate the seasonal variability. Water data analysis and modelling of water systems are on-going in WP3. WP5 (Sustainability) started with sustainability hot spot screening.

At this stage of the project after the first 18 months, a significant amount of on-line data has been collected and analysed from the plant feed. The reactivity of tailings and waste rock has been determined. The required material properties for backfill and covers were evaluated. Water samples from the mines have been extensively characterized. Data analyses were conducted to find correlations between mineralogy, water quality and plant performance. On-line sensors have been developed for target ions to be used for water quality measurements in flotation plants. The preliminary sustainability assessment showed hotspots for the various dimensions of sustainability. The results confirm that water use and closing water cycles are the main pressing issues in mining, which in turn reinforces the relevance 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 develops new holistic water and waste concepts and systems, which will result in higher technical, economic and environmental performance in raw materials production. The developed ITERAMS water and waste efficient concepts are jointly validated by industrial and research partners at their mine sites. Three sites at Boliden (Finland), Somincor (Portugal) and Anglo American (Chile or South Africa) were selected to validate the results in various conditions, for example in various mineralogical and geographical areas. Information from laboratory tests, process assessment and technology validation is used for development of the water recycling testing protocol.

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.