Ojamo mine is located near the town of Lohja, approximately 60 km (37miles) west of Helsinki. It now serves as a technical divers´ training spot which suitably uses its multiple levels and year round crystal clear 4°C (39 °F) fresh water. During the summer months it also serves as a convenient open water training facility. Find the place on the map of Adrex.com Locations...
The flooded parts and tunnels of the mine range from several depth levels starting at 30 meters (98 feet) and continuing to over 200 meters (650 feet). Maximum estimated depth is around 250 m but according to Adrex.com information it hasn´t been explored by any diver yet. So far the deepest reported dives here were into 160 meters. The quarry dive is through the main shaft that slopes about 45° (see the map below).
Next to the main pit and several main tunnels you can also explore immense halls dug in the rock. The longest tunnels are situated at the 88 meters level, which used to be the main mining level of the quarry. The longest tunnel measures slightly less than 2 km. All the tunnels are stable and without any supporting struts.
