Rääpysjärvi – Graphite
Rääpysjärvi (also called Tuusniemi) is a 716 ha exploration area located approximately 10km north east of the Haapamäki/Pitkäjärvi fold hinge, in the southern part of the Tuusniemi municipality.
Geologically, the area is situated within the eastern Savo province of the North Karelia Schist Belt (NKSB). Petrologically, the rocks are classified as North Karelian supracrustal rocks. The lithology comprises mostly of Paleoproterozoiz sedimentogen mica schists, named historically as Savo schists, deposited into a rift basin adjacent to the Karelian craton.
Historically, the area contained a known, graphite quarry and drilling had been carried out in the vicinity of lake Rääpysjärvi.
More recently, several exploration programmes have been carried out in the area. In 2015, bedrock mapping tested the area, however several anomalous areas were still left unexplored. In 2017, further mapping was carried out to follow up the strong aero-electromagnetic anomalies and the GTK black shale interpretations over the area, and to locate the historic graphite quarry. The quarry was eventually located at a low small outcrop ridge and is currently a 10x4m water filled pit 2-3m deep.
There has also been drilling in the area with results indicating graphite intersects. This increases the prospectivity potential around the nearby anomalies. Similar to Haapamäki/Pitkäjärvi, the Tuusniemi region also consists of strong aero-magnetic anomalies, but the exploration work was mainly based on electormagnetic anomalies.