Eimear Deady

A review of the potential for rare earth element resources from European red muds: examples from Seydişehir, Turkey and Parnassus-Giona, Greece

Abstract Rare-earth elements (REE) are viewed as ‘critical metals’ due to a complex array of production and political issues, most notably a near monopoly in supply from China. Red mud, the waste product of the Bayer process that produces alumina from bauxite, represents a potential secondary resource of REE. Karst bauxite deposits represent the ideal source material for REE-enriched red mud as the conditions during formation of the bauxite allow for the retention of REE. The REE pass through the Bayer Process and are concentrated in the waste material. Millions of tonnes of red mud are currently stockpiled in onshore storage facilities across Europe, representing a potential REE resource. Red mud from two case study sites, one in Greece and the other in Turkey, has been found to contain an average of ~1000 ppm total REE, with an enrichment of light over heavy REE. Although this is relatively low grade when compared with typical primary REE deposits (Mountain Pass and Mount Weld up to 80,000 ppm), it is of interest because of the large volumes available, the cost benefits of reprocessing waste, and the low proportion of contained radioactive elements. This work shows that ~12,000 tonnes of REE exist in resources existing across Europe as a whole.

Rare earth element placer deposits and alkaline volcanics: a case study from Aksu Diamas, Çanakli, Turkey

included detail on the igneous facies and simply have attempted to recognise weathered flow tops. Hitherto the Lower Basalt Formation was considered internally consistent despite having a geographical extent of over 3500 km and a variable thickness, which in areas has been recorded up to 531 m. The lack of robust and detailed stratigraphical information for the unexposed parts of the Antrim Plateau presents a significant hindrance to exploration that relies on information about the location and distribution of feeder systems (dykes, sills and plugs). In an attempt to address this lack of stratigraphic information we have undertaken detailed graphical logging of two cores from the Carnduff area, a field section from Browns Bay, Island Magee, as well as comprehensive petrographical analysis. The study focuses on the lowermost 160 m of the basalts from which it is clear that there are complex internal variations. The basalts were formed by a series of tabular and compound flows most of which can be correlated laterally across the area. By identifying and characterising the geometry and morphologies of these flows, it is possible to break the Lower Basalt Formation down into three smaller lower and upper units consisting of tabular basaltic lava flows and the middle unit of much smaller compound flows. Ultimately, the aim is to generate a robust stratigraphic model for the Lower Basalt Formation that can be applied elsewhere on the plateau to correlate key flows at the base of the Antrim Lava Group. By mapping these flows across the area it may be possible to locate mineralogical important feeder dyke systems.

Volcanic ash-fall placers: a new type of REE deposit?

The Çanakli deposit, a part of the Aksu Diamas project in western Turkey, owned by AMR Mineral Metal Inc., has an inferred resource of 494 million tonnes at 0.07% TREO (total rare earth oxide) in unconsolidated sediments at surface. This deposit is a potentially important source of European rare earth element (REE) supply. Alternative supplies of critical minerals are being intensely investigated across the globe, with a focus on by-product or added-value minerals such as REE, for example from alumina processing (Deady et al. 2016) and phosphate production (Emsbo et al. 2015). The deposit is hosted in Quaternary sediments situated in a basin in Mesozoic limestone. REE-bearing heavy minerals occur in lenses and are disseminated in channelised debris flows. There is no obvious source of these minerals within the basin catchment. However, the alkaline Gölcük volcano is located approximately 20 km north-west of the deposit and repeatedly erupted during the Plio-Quaternary (Platevoet et al. 2014). The related ash falls represent a potential source for the REE-bearing minerals. The source of the REE is being investigated by the British Geological Survey through the EU-funded FP7 project EURARE (www. eurare.eu). Scanning electron microscopy (SEM) analysis of heavy mineral concentrates has confirmed the presence of REE-bearing minerals such as allanite and chevkinite. These minerals are also found in samples of pyroclastic material from the Gölcük alkaline volcano. Chemical fingerprinting of both major minerals, such as magnetite and pyroxene, and the minor REE-bearing minerals, using a combination of LA-ICP-MS and quantitative SEM, is used to investigate the potential for Gölcük as the source. If the Çanakli REE deposit resulted solely from the accumulation of air-fall tuff-borne minerals in a topographic depression, without additional concentration processes, then this is a new type of deposit. Improved understanding of the origin of this deposit type would aid identification of additional REE resources in similar settings globally, including those at Monte Vulture, Italy.

Ore fluid characteristics of antimony deposits in South West England: new insights into ore genesis in Wadebridge-Port Isaac and Herodsfoot

Ore fluid characteristics of antimony deposits in South West England: new insights into ore genesis in Wadebridge-Port Isaac and Herodsfoot H. Knight∗1, É. Deady, A. G. Gunn, K. Moore and J. Naden Camborne School of Mines, University of Exeter, Penryn Campus, Treliver Road, Penryn TR10 9EZ, UK (humphrey.knight@geolsoc.org.uk) British Geological Survey, Environmental Science Centre, Nicker Hill, Keyworth, Nottingham NG12 5GG, UK

Valorisation of waste material – rare earth elements in red muds: The potential of European resources

Abstract Abstracts from the 38th Annual Winter Meeting of the Geological Societys Mineral Deposits Studies Group held on 18–19th December 2014 at the University of Southampton, UK. The meeting was organised by Dr Robert Knight from the University of Southampton.