Kainuu – Talvivaara Belt
The recent advancement of the low grade, high tonnage (414 Mt) open pit deposit at Talvivaara to development and production has renewed interest in the metaliferous black schists, within the Kainuu Schist Belt of central Finland, which in size and aerial extent are unique to this part of the world. Magnus has acquired a large land position covering a number of known deposits and prospects of the Talvivaara type. The most advanced is Rautavaara, some 50km south of Talvivaara, which has a drill inferred tonnage of 21 Mt from surface to 100m level, of nickel, zinc, copper and cobalt similar in grade to Talvivaara and is open along strike and at depth. The deposit is at the north end of a 10km long belt of mostly untested metaliferous black schists. In addition, Magnus has ground in potential rocks near the Talvivaara deposit as well as along a belt extending over 50km to the north.
Rautavaara
Quick Facts:
- Low grade, high tonnage Ni-Cu-Zn-Co deposit
- Drill inferred tonnages of 21 Mt of 0.1% Cu, 0.21% Ni, 0.45% Zn & 0.02% Co (Ag content unknown) from surface to 100m level at Pappilanmäki.
- Grade and size potential comparable to Talvivaara Mine which has production reserves of 414 Mt of 0.26% Ni, 0.14 Cu, 0.54% Zn, 0.02% Co, 3 g/t Ag.
Exploration History
Mineralization in the form of base metals, silver and gold in boulders and bedrock have been known from the Rautavaara area since early times and some small scale mining has been done in the past (e.g. Saastamoinen Mining Co. for high-grade copper). The only exploration on the Rautavaara Belt was by GTK in late 1970’s when the area was prospected for boulders, till geochemical, ground magnetic and EM surveys were done, and some drilling was carried out (Sipilä, 1980 GTK report). This is the only known exploration and data known. Magnus has compiled in GIS and interpreted all the data and as a result, has covered most of the potential rocks along the belt with 13 claims. The following is based on Magnus’ work and that of Sipilä.
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The Pappilanmäki deposit is located at the northern end of a 10km long, belt of Talvivaara-type rock comprising altered ultramafics, quartzites, skarns, sediments and black schists. The steeply-dipping zone of the mineralization is magnetic because of massive to disseminated pyrrhotite and is largely confined to ‘altered quartzite’. Limited drilling and ground magnetic surveys by GTK in the 1970’s indicate the zone to vary from 25m thick at the north end to 300m wide in the main part and to be open along strike to the SE and at depth.
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Limited exploration at the south end of the belt at Korpimäki has revealed similar mineralization along a 2km long conductive magnetic anomaly in a sequence of rocks similar to Pappilanmäki. In the strongest part of the conductor, one of the dozen widely spaced holes intersected zinc values in the range of 1-2% along with low grade Ni, Cu, and Co and below this, Zn averaged 0.27% over 50m with Cu and Ni values < 1%.
Tests carried out on the ‘ore’ from Pappilanmäki and Korpimäki at Outokumpu’s lab in Pori in 1980, revealed the Ni to be easily separated because it is present as pentlandite associated with pyrrhotite with negligible amounts in silicates.
Other Magnus Properties
The Kainuu-Talvivaara Belt hosts ‘black schist’ sequences similar to that found at Talvivaara and Rautavaara for a strike length of more than 100km to the north of Rautavaara. Magnus holds claims and claim reservations on potential rocks 2km east of the Talvivaara Mine, at Jormua and Paltamo, 40km and 50km north of Talvivaara, respectively.
Potential
At Pappilanmäki, potential exists to prove up a high tonnage, low-grade deposit, amenable for open pit mining, as well as to discovery new deposits of similar or better grade in the 7km of untested coincident EM and magnetic anomalies south along the belt to Korpimäki. Similarly, Talvivaara type deposits may occur on the Magnus properties in the northern part of the Kainuu Belt, where limited past drilling has indicated mineralization in black schists.
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