THORIUM AS AN ENERGY SOURCE - Opportunities for Norway ...

Thorium Resources in Norway
The potential production of thorium concentrate from the Fen Complex will depend on the grainsize
of thorium enriched minerals. Flotation is a well-established traditional method for mineral
separation. In sulphide flotation the processes can utilise mineral grain sizes down to 20
micrometers (10 -6 m) in the best cases [12]. In pegmatite flotation the mineral grain size has to be
larger than 50 micrometers to get a satisfactory recovery. In the Megon report (1973) the
possibility of exploiting the rare earth elements (REE) in the Fen carbonatite was evaluated. The
conclusion stated that the REE minerals were so fine-grained that REE could not be enriched
with satisfactory recovery using traditional techniques from the 1960s and 1970s. Therefore,
other more advanced methods for mineral separation should be utilized and adapted to the
specific deposits, but in general, separation of very fine-grained minerals is a great challenge.
Investigation on possible exploitation of thorium in minerals from the Fen Complex is currently
proceeding. Based on archive iron-rich carbonatite samples, including drill cores, the Geological
Survey of Norway has performed a preliminary study of the mineralogy [12]. Using electron
microscopy, the grain size of the Th-containing minerals was found to be about 1 micrometer
(Figure 3.4), indicating that the grain size of the Th-minerals is too small for enrichment by the
traditional flotation processes. This is in accordance with previous mineralogical investigations,
although a maximum grain size for REE minerals of 40 micrometers has been observed locally.
Thorium occurs predominantly in the mineral monazite, but occurs also in other minerals,
especially in REE minerals.
Figure 3.4: Photo of a Thin Section of Fen Iron-Rich Carbonatites Examined on SEM-Electron Microscope.
(Source: A. Korneliussen, Geological Survey of Norway, NGU)
3.3 Summary of the Thorium Resources in Norway
Figure 3.5 shows a geological map of Norway where the thorium rich areas are indicated.
According to present knowledge most of the thorium enriched minerals are situated within the
Fen Complex in Telemark County, the Permian Oslo Province covering Vestfold, in the Southeast
coast of Norway covering the Kragerø and Langesund area, as well in Aust-Agder, Nord-
Trøndelag, Nordland and Finmark.
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