The potential for production from small, high-grade ore deposits in Europe can be viewed using a dedicated data layer in the existing EU Minerals Knowledge Data Platform (EU-MKDP) (
http://minerals4eu.brgm-rec.fr/minerals4EU/(se abrirá en una nueva ventana)). Rapid screening of the “Small scale complex deposits” is of use to exploration and mining companies, and other stakeholder groups. Enhanced data acquisition at the outset of exploration is supported by an initial petrographic reporting strategy that includes semi-quantitative mineral liberation data. The early identification of challenges for processing and subsequently valorisation of a deposit allows the operator to focus on the most prospective deposits. A small-spaced geostatistical sampling approach was used to further describe variability ore veins as a means to determine business risk.
Mining and processing units were design to fit and/or operate in 20 foot long containers. The cutting head of the selective mining tool controlled particle size, thereby reducing the need for primary crushing. Operational challenges arising from reduced run-of-mire after selective mining were examined using a one-container comminution circuit, deployed to site in half a day. An XRF ore sorter of reduced dimensions for a one-container module created sufficient high-grade stockpile of ore for the gravity beneficiation plant to operate in semi-continuous mode. The mobile processing test facility comprises four twenty-foot containers connected by walkways and modified for attachment of jigs and spirals, with flexible piping and electrical configuration for adaptability to different mine sites and run-of-mine feed. It was deployed in just three days, such that the system has proven ability to respond to market demands, where there is adequate licensing in place.
Tests at the Olovo lead mine site (Bosnia and Herzegovina) constituted in-situ processing activity. The second test site was the processing site at Veliki Majdan, treating ore from Zajača antimony mine in a satellite mining and processing model. Samples and data were generated to test simulations of ‘switch on’ or ‘switch off’ (SOSO) mining and processing, where limited knowledge existed of variable ore deposits. Objects were tracked through the different stages of the process using a combination of advanced scanning and liberation analysis. Process flowsheets arising from desk studies and metallurgical testwork supported operations at test sites, were used to consider alternative antimony deposits and legacy wastes, and underpinned review of the suitability of chemical reagents for adaptable process solutions.
Environmental life cycle analysis showed that electricity generation was the key environmental hotspot, though other environmental impacts also required consideration. For SOSO mining, modelling showed that renewable energy or mixed renewable-energy diesel solutions were amenable to off-grid operations and more cost-effective than diesel-only energy provision. Water quality was predicted using a rapid infra-red technique and a treatment plant for industrial water was designed for increased modularity and portability. A research framework for evaluating the social impacts of switch on – switch off mining and social life cycle analysis were used to investigate perceptions of SOSO mining and measures that can be put in place by the mining operator. Community expectations for generations of employment in mining operations were largely informed by positive perceptions of past industrial operations in historic mining districts. The concept of small-scale mining was defined for a European context in terms of societal impact, as distinct from small deposit mining. Recommendations and training were devised to protect workers within a mature health and safety culture for SOSO mining.
Unless commercially sensitive, the results of the project are published, in preparation for publication/review, and/or disseminated at conferences and stakeholder workshops, including to industrial stakeholders. Policy-level dissemination included a meeting with ministers in Sarajevo ahead of on-site test work and circulation of a policy brief to the UK government ahead of the G7 summit and COP26. Dissemination to the public has culminated in an art collaboration and book publication: ‘Of Earth – For Earth. The meaning of a mine’.
