Montolan kaivos

Visibility in the drifts is excellent year-round, best in winter. The main routes are marked with coloured guidelines. You see pillar halls, rails and ore carts, electrical panels, dynamite boxes and a large rock crusher. In winter pumps keep a hole open and there are habitats at -6 m (one for four people, two single ones).

Montolan kaivos is a dolomite and limestone mine in Montola village, ~18 km south of Pieksämäki. Lime was burned here from 1904; the mine itself was worked from 1909 to 1976 (nearly 4 Mt, up to ~250 miners), until inflowing groundwater made mining unprofitable and the mine flooded. Since 1995 the area has officially been an important groundwater area, and until 2015 the mine was one of Pieksämäki's official water intakes. After a diver died in November 2008 the Ministry of Trade and Industry imposed a ban, but divers carried on through a mining claim under the old mining law (Yle, 2012). Diving has been officially allowed since April 2016, through an association of dive clubs from Pieksämäki, Mikkeli, Savonlinna, Varkaus, Kuopio and Jyväskylä; its site now lists 3,850 dive events. Per Yle (2017), the Ojamo mine in Lohja is the other comparable site in Finland.

Practical: maps are online and in the changing room. Entering the mine without a guideline is forbidden; permanent lines only by designated people, temporary lines are removed after the dive. In winter there is de-icing on the stairs; under ice only with a surface line or as a cave diver using cave technique. Oxygen and AED are in the grey changing room. As a visitor you register in the Finnish-language portal and sign up for a guest event ('vierastapahtuma'), which is open to all registered divers; weekend events fill up fast, so weekdays are a good alternative. Instructors and students pay a separate training fee on top of the event fee. If you come from further away, you can stay at the village guesthouse (8 places; using your own compressor is allowed).