The Geological Survey of Finland (GTK) has published the results of an evaluation of undiscovered cobalt (Co) and gold (Au) resources in Kuusamo-type Co-Au deposits in the Finnish bedrock to a depth of one kilometre. These deposits resemble, to some extent, the Blackbird-type cobalt deposits in Idaho, USA.
Altogether, eight permissive areas that could contain Kuusamo-type Co-Au deposits were delineated in Finland. The areas are expected to contain approximately 58 undiscovered deposits.
At the 50 % level of probability, the undiscovered Kuusamo-type Co-Au deposits in Finland contain at least 100,000 metric tons (t) of cobalt and 85 t of gold. The results of this assessment indicate that at least 80 % of the remaining Kuusamo-type cobalt endowment in Finland occurs in poorly explored or yet undiscovered deposits.
In light of the present assessment and previous GTK assessments of undiscovered cobalt in magmatic nickel deposits and Outokumpu-type polymetallic deposits, the undiscovered cobalt endowment can be expected to form at least 20–40% of the total cobalt endowment in the Finnish bedrock.
There are 10 well-known Kuusamo-type deposits, and all of these are located in the Kuusamo area in north-eastern Finland. Together, these deposits contain 22,000 t of cobalt and 19 t of gold.
The eight permissive areas delineated for Kuusamo-type cobalt-gold deposits cover 21,082 km2, which is approximately 6 % of the total land area of Finland. All of the permissive areas are located in northern Finland, and approximately 50 % of the estimated undiscovered Kuusamo-type cobalt resources are located within the Kuusamo and Peräpohja schist belts.
GTK has assessed the undiscovered metal resources in Finnish bedrock since 2008. The assessments are carried out using the three-part assessment method developed by the U.S. Geological Survey. Areas that could contain certain types of ore deposits are delineated based on deposit models, the numbers of potentially existing undiscovered deposits in the areas are estimated, and the quantities of metals contained in the undiscovered deposits are calculated at several levels of certainty. The assessment does not take a view on the amount of undiscovered resources that will possibly be discovered.
The results of the survey have been published in GTK’s Bulletin 410:
Rasilainen K., Eilu P., Huovinen, I., Konnunaho, J., Niiranen, T., Ojala, J., Törmänen, T. 2020. Quantitative assessment of undiscovered resources in Kuusamo-type Co-Au deposits in Finland. Geological Survey of Finland Bulletin 410, 32 pages, 10 figures, 6 tables and 3 appendices. Available online at: http://tupa.gtk.fi/julkaisu/bulletin/bt_410.pdf
For further information, please contact:
Geological Survey of Finland
Kalevi Rasilainen, Geologist, tel. +358 (0)29 503 2401 or +358 (0)40 722 9850, email@example.com
Pasi Eilu, Senior Scientist, tel. +358 (0)29 503 2565 or +358 (0)40 864 9165, firstname.lastname@example.org
Link: The downloadable map shows areas that can contain undiscovered Kuusamo-type cobalt-gold deposits. Known Kuusamo-type deposits are shown as red dots. Link to the map.