Rasilainen, K., Eilu, P., Äikäs, O., Halkoaho, T., Heino, T., Iljina, M., Juopperi, H., Kontinen, A., Kärkkäinen, N., Makkonen, H., Manninen, T., Pietikäinen, K., Räsänen, J., Tiainen, M., Tontti, M. & Törmänen, T. 2012. Quantitative mineral resource assessment of nickel, copper and cobalt in undiscovered Ni-Cu deposits in Finland. Geologian tutkimuskeskus, Tutkimusraportti 194 − Geological
Survey of Finland, Report of Investigation 194, 514 pages, 14 figures, 10 tables and 6 appendices. (En.)
Первоисточник: http://en.gtk.fi
Nickel, copper, and cobalt resources in undiscovered Ni-Cu deposits associated with Palaeoproterozoic synorogenic intrusions and Archaean and Palaeoproterozoic komatiitic volcanic rocks have been estimated down to the depth of one kilometre in the bedrock of Finland using the three-part quantitative assessment method. Grade-tonnage models were constructed for Finnish synorogenic intrusive deposits and komatiitic deposits using data from known Fennoscandian deposits. Twenty-six permissive tracts were delineated for synorogenic intrusive deposits, 30 for komatiitic deposits, and 15 for Talvivaaratype Ni-Zn-Cu-Co deposits. Altogether, the tracts cover an area of 65 700 km2, which is 20 % of the total land area of Finland. The mean estimate of the number of undiscovered synorogenic intrusive deposits within the permissive tracts is 66, and that of undiscovered komatiitic deposits is
34. At 50 % probability, the undiscovered synorogenic intrusive deposits are estimated to contain at least 480 000 t Ni, 200 000 t Cu and 23 000 t Co, and the undiscovered komatiitic deposits are estimated to contain at least 280 000 t Ni, 59 000 t Cu and 10 000 t Co. Estimation of the number of undiscovered deposits and the amount of undiscovered metal in Talvivaara-type deposits could not be performed due to the lack of grade and tonnage data from completely delineated deposits. About 52 % of the Ni+Cu+Co endowment in synorogenic intrusive deposits and 87 % of the Ni+Cu+Co endowment in komatiitic deposits in Finland occur in poorly explored and undiscovered deposits. Most of the undiscovered synorogenic intrusive nickel resources are located within permissive tracts around the Central Finland Granitoid Complex. The Kotalahti and Vammala tracts together are estimated to contain 52 % of all the undiscovered intrusive Ni+Cu+Co resources. The undiscovered komatiitic resources are evenly distributed between the greenstone belts of northern and eastern Finland. Both areas are estimated to contain about 50 % of the total undiscovered komatiitic Ni+Cu+Co. The Kuhmo–Suomussalmi tract is estimated to contain 30 % of all Ni+Cu+Co in undiscovered komatiitic deposits. The known synorogenic intrusive and komatiitic deposits contain 471 000 t of nickel, which is only 10 % of the known nickel resources in Finland, although most of the known nickel
deposits belong to either of these two types and the overwhelming majority of nickel produced from mines in Finland prior to 2009 came from synorogenic intrusive deposits. The large Kevitsa and Talvivaara deposits together contain 4 234 000 t of nickel. At 50 % probability, the undiscovered nickel resources in synorogenic and komatiitic deposits in Finland are at least 760 000 t Ni. This is 15 % of the total estimated undiscovered nickel resources of 4 960 000 t of Ni in Finland.
