Quantitative assessment of nickel resources in magmatic Ni-Cu sulphide deposits in Finland

The undiscovered Ni resources in Finland have been assessed to one km depth using the three-part quantitative mineral resource assessment method. Paleoproterozoic synorogenic mafic-ultramafic intrusion-hosted as well as Archean and Paleoproterozoic komatiite-hosted magmatic Ni-Cu sulphide deposits were included in the assessment. Deposit models were constructed for both deposit types using publicly available data from deposits within the Fennoscandian shield. Tracts permissive for the deposit types were defined and the number of undiscovered deposits within each tract was estimated. The amounts of undiscovered Ni, Cu and Co metal were calculated using Monte Carlo simulation. The expected (mean) numbers of undiscovered deposits for the intrusion-hosted and komatiite-hosted types are 66 and 33, respectively. The estimated undiscovered resources in orogenic intrusion-hosted Ni-Cu deposits in Finland at 50% probability are at least 480,000 t Ni, 200,000 t Cu and 23,000 t Co. The corresponding figures for undiscovered komatiite-hosted deposits are 270,000 t Ni, 56,000 t Cu and 9,500 t Co. These results indicate that 55-60% of orogenic intrusion-hosted or komatiite-hosted Ni, Cu and Co resources in Finland occur in undiscovered or poorly studied deposits.