Mine diving in Finland

• Access: in Finnish mines you dive via the association that holds the rights. Ojamo (Lohja) and Montola (Pieksämäki) only at events of Ojamon Kaivossukeltajat ry and Montolan Kaivossukeltajat ry (membership/registration in their portal; independent diving not allowed). At Ojamo you share the pit with the training institutions Meriturva and Luksia; the city has leased the diving base to a non-commercial association since 1 July 2024. Kaatiala: no booking needed (everyman's right). Paakkila: private land, notify the owner (via Kuopion Urheilusukeltajat ry or the Paakkila Facebook group); free. • Rules: Montola (2024 safety document) — open water CMAS P1, mine at least Intro to Cave or equivalent, thirds, CCR bailout ≥1.5×, max END 40 m, max one dive deeper than -40 m per day, no entering the mine without a guideline, under-18s not in the mine. Ojamo (ojamodive.fi) — dive plan to the organiser, dive leader and a safety diver on standby, support team for dives >60 m or >180 min; under ice a surface line and cave or mine certification (Yle 2026). • Water and season: the mines are ~4 °C at depth all year. The pits reach ~20 °C in summer, but visibility then drops to ≤1 m (algae) and in autumn sometimes to near zero (humus); winter gives the clearest water. In winter Ojamo and Montola keep a hole open with pumps; Montola has de-icing on the stairs and habitats at -6 m, Ojamo heated changing huts. Drysuit with dry gloves and heating; Finnish divers inflate their suits with argon. • Gas: no public trimix or O₂ station found near Lohja; Arctic Divers in Helsinki fills air (200/300 bar). Finnish clubs run their own compressors and mix stations for members (e.g. Jyväskylän Delfiinit, a founding club of the Montola association: nitrox, O₂, trimix, argon) — ask your event organiser. Finnish rules (Tukes): O₂-cleaned cylinders are marked 'OXYGEN-SERVICED' with who serviced them and when, mix cylinders are labelled NITROX/TRIMIX/OXYGEN, and the fill station records the last periodic inspection — bring cylinders with a valid test. • General mine caution: old installations remain (rails, carts, lamps, tools, cables) — entanglement and sharp metal; silt comes down from the ceilings; never breathe the air in an air pocket. • Accident: call 112 and start oxygen; for mild symptoms contact your health service or DAN Europe +39 06 4211 5685 (24/7; also online emergency call via emergencycall.daneurope.org). Finland's national hyperbaric oxygen therapy centre is at Tyks, Turku University Hospital; Tyks emergency department (T-hospital): Savitehtaankatu 1, door 18O, Turku, 24/7; medical advice line 116117. No direct chamber number found — go through 112. At Montola, oxygen and an AED are in the changing room. • Distances: Ojamo is ~60 km west of Helsinki; Montola is in Montola village, ~18 km south of Pieksämäki; Kaatiala (Kuortane, South Ostrobothnia) and Paakkila (Tuusniemi, ~70 km from Kuopio) are far from Lohja — plan them as separate trips. • Rest day: Tytyri Mine Experience (mine museum) in Lohja, with an underground gallery ~100 m down (it showed Ojamo mine-diving photos in 2024); the Ojamo iron mine (from 1542, the oldest known in Finland) is on private manor land — visit via Lohja's tourist service or on open days.