On July 26, 2024 the Eurobattery Minerals AB exercised its option to acquire the remaining 30 per cent of FinnCobalt Oy, the owner of the ground and mining rights to the nickel-cobalt-copper project Hautalampi.
Following the closing of the acquisition, Eurobattery Minerals’ share of ownership in FinnCobalt amounts to 100 per cent.
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Summary:
The Hautalampi mineralised zone is the south-westernmost part of the Co-Ni- Cu-mineralisation zone, which is situated within the hanging wall roughly parallel to the Outokumpu Keretti Cu-ore body. It belongs to the “Outokumpu- type” deposits within the rock associations of the Outokumpu Formation.
The Co-Ni-Cu zone has some aspects that are distinct to the main Cu ore environment. One is the frequent occurrence variably cummingtonite, anthophyllite, cordierite (usually extensively pinitised), staurolite, garnet, phlogopite, and spinel-bearing chlorite-rich rocks/schists, hosted as thin layers (usually < 1m) or patches in skarn (diopside-tremolite)-quartz rocks forming the bulk of the Co-Ni-Cu zone. Another distinct feature is the abundance of often very coarse-grained, usually highly zincian chromite in almost all the rock types in the zone. And a third one is the relative cobalt-nickel enrichment of the included sulphide mineralisation (modified from the GEOMEX Report and references therein).
It was earlier thought that the Hautalampi zone represents a feeder zone for the main Keretti Cu-ore. According to the now widely accepted Geomex model the silicate nickel was transformed to the sulphide fraction during the obduction and adjacent carbonate-quartz alteration of the seafloor around 1.9 Ga. After that, during the areal deformation phases D1-2, the Ni-bearing sulphides were remobilised and recrystallised. It is important to note that according to both models, the nickel-enriched zone was made before the folding. Consequently, understanding the fold structures at Hautalampi is important in trying to follow the mineralised zone.
Mineralization
The lower edge of the Co-Ni-Cu-mineralisation zone is typically some 150 to 200 m above and a bit to the NW of the upper edge of the main Keretti Cu-ore. Dimensions of the modelled Hautalampi mineralised zone are approximately 1000 m in length, 100-150 m in width, and 1-30 m in thickness. Some drill holes indicate that in the NW parts the mineralisation is cut by the present erosion surface. Mineralisation has a 10 - 55° dip to the SE (on average about 25-30°). The main part of the mineralisation is 70-120 m below the surface and the deepest parts of the known mineralisation are about 150 m below the surface.
Mökkivaara mineralisation is located approximately 650 meters northeast of the Hautalampi mineralisation and it has the same overall strike and dip as the Hautalampi mineralisation. More work is needed to gain confidence in the geological setting of Mökkivaara. Old interpretations suggest that the mineralisation is in synform but according to the latest drillings, the data supports an antiform structure.
The Co-Ni-Cu mineralisation, (also referred to as the Hautalampi mineralisation), consists of tightly folded metamorphic rocks. Host rocks are mainly quartz rocks with anthophyllite-tremolite skarn bands and interlayers with variable amounts of chlorite. In some places, the mineralised zone is also hosted by skarniferous dolomitic rocks. Minor diopside can occur with other skarn minerals. In places, there is also nickel-bearing black schist or black schist-bearing quartz rock in the footwall. Mineralisation mainly occurs as disseminations in bands due to metamorphosis. The mineralised zone has in places a very sharp contact with the wall rocks. However, in many places, a transitional zone from one meter up to three meters occurs between the mineralised zone and wall rocks.
Chlorite schist is locally rich in garnet and also minor cordierite is present. Garnet and cordierite occur as porphyroblasts. Phlogopite occurs in quartz rocks and it seems to be an alteration product of amphiboles. Also, cummingtonite, staurolite, and spinel are mentioned in the GEOMEX report. Chromite and its alteration products, ferrian chromite and magnetite, are present in almost all the host and wall rocks, especially in rocks that are rich in quartz and dolomite. Serpentinites contain thin magnetite bands and magnetite grains are typical.
The hanging wall rock is mainly serpentinite and quite often also quartz rock and dolomite with or without diopside-tremolite skarn bands or interlayers. Footwall rocks are quite often the same due to folding. Rock types vary a lot through a drill hole, especially between skarn-, skarniferous quartz and quartz rocks.