1894 red-rock clasts within FDC and damtjernite breccias. REE enrichment within the FDC is typically pervasive and laterally consistent across exploratory drill holes, with structural permeability (faulting/brecciation) acting as the key control on hematitization intensity and local REE concentration. Figure 1 shows a simplified geological map of the Fen Complex in the project area. Mining of different commodities has previously been carried out within the Fen Complex. Iron mines were operated from the 1650s to 1927 on hematite ores within the “rødbergite” (Dahlgren, 2006). Søvite was mined for niobium in the period 1953 to 1965. Figure 1 – Simplified geological map of the Fen Complex (Dahlgren, 2006). REE enrichment of the FDC unit (Fe-Dolomite Carbonatite, “Rauhaugite”), generally is pervasive and consistent with an elevated level of REEs evident throughout the majority of exploration drill holes within this unit. The 16 REE found at Fen include, Cerium (Ce), Dysprosium (Dy), Erbium (Er), Europium (Eu), Gadolinium (Gd), Holmium (Ho), Lanthanum (La), Lutetium (Lu), Neodymium (Nd), Praseodymium (Pr), Samarium (Sm), Scandium (Sc), Terbium (Tb), Thulium (Tm), Ytterbium (Yb), Yttrium (Y). Deleterious elements include Lead (Pb), Thorium (Th), and Uranium (U). 3. GEOTECHNICS AND ROCK MASS QUALITY Rock mass classification for the Fen deposit supports mine design using ~7,300 m of geotechnical core logging and three schemes (RMR, Barton Q, GSI). The steep, massive Fe-dolomite carbonatite (FDC) forms a competent rock mass, but brecciation, veining, dyke intrusion and alteration/fenitization create localized weak zones. Oriented core defined borehole-specific joint sets underpinning RMR/Q inputs and kinematic/stability checks. Short intervals captured RQD, fracture frequency/spacing, joint condition, groundwater and defects. Deposit averages show high quality (RMR ~74, GSI ~76, Q ~273); variability is controlled by discrete weak intervals. Point-load and ISRM hammer tests indicate medium-strong to verystrong intact rock.
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