Besucherbergwerk Kleinenbremen – Blaue Lagune
A former iron-ore mine (Grube Wohlverwahrt) at Kleinenbremen near Porta Westfalica, opened as a show mine in 1988. In its lower section groundwater flooded the workings after the pumps were switched off, forming the 'Blaue Lagune', an underground lake far inside the mountain. Divers reported very clear 7–8 °C water, a depth of about 20 m and a guideline; there is little life, just rock and sediment. Equipment was carried in by the mine railway.
Facts
- Region: Germany – Mines & Caves
- Area: NRW, Sauerland & North Hesse
- Depth: 0–20 m
- Level: advanced
- Current: low
- Type: cave
- Coordinates: 52.2296292, 9.0408963 (approximate)
- Highlights: flooded mine: underground lake 'Blaue Lagune', very clear water, one of Germany's clearest dive waters (2015 report), water about 7–8 °C, about 20 m deep with a guideline, gear transported by mine railway
- Permit: Show mine; diving was possible only with the operator's consent in organised groups. Ask Besucher-Bergwerk & Museum Kleinenbremen gGmbH about current diving. Check current status.
- Issuer / contact: Besucher-Bergwerk & Museum Kleinenbremen gGmbH
- Phone: +49572290223
- Email: info@bb-mk.de
- Address: Rintelner Straße 396, 32457 Porta Westfalica
- Website: https://bergwerk-kleinenbremen.de/
- Unverified: Diving is documented only by sources from about 2009–2016 (travelbook.de 2015, taucher.net reports); the organiser's domain trevpunkt.de no longer resolves and the mine's website does not mention diving. Current availability is unknown. Position is the mine's address (OSM).
- Tips: Dives were run about once a month for small groups by an external organiser (Trevpunkt, Trevor Barritt), with a long waiting list. Reported requirements: at least 50 (cold-water) dives, drysuit and cold-water gear, safe drysuit handling, a dive medical, diving-accident insurance, minimum age 18; helmet compulsory in the mine. The organiser's website no longer resolves and the mine's own site does not mention diving – ask the mine before planning. Check current status.