Sweden

Sweden combines two distinct overhead cultures. In Jämtland, Bjurälven is a winter-only natural karst exploration project shaped by low-flow Arctic conditions. Farther south, centuries of mining produced a highly organised mine-diving network with common rules, site-specific progression and strong industrial-heritage documentation.

The Bjurälven river disappears into a narrow limestone belt near Stora Blåsjön and resurges kilometres downstream. Bo Lenander identified the possible Dolinsjön entrance in 1979. Summer flow proved extreme, so the modern project established late winter as the practical exploration window.

Expedition Bjurälven began in 2007 and has become a long-running research project. Dolinsjögrottan is surveyed to 2,432 m and the wider cave cluster to roughly 3.35 km. The route is shallow by depth standards but demanding: tight sidemount entry, a first sump approaching 500 m, five sumps, four dry sections, sand restrictions, loose rock and multi-hour logistics.

Access is research-based. The valley is a nature reserve and Natura 2000 area; underwater cave diving requires County Administrative Board permission, with separate permissions for protected-valley transport.

SvenskGruvdykning coordinates core rules across A-gruvan, Långban, Nordmarksberg, Sala Silvergruva and Tuna-Hästberg. Shared principles include no solo diving, protection of permanent lines and artefacts, formal overhead competence for relevant routes, and progressive approval for deeper or more complex dives.

• ›Tuna-Hästberg / Äventyrsgruvan — 7+ km guideline, heated facilities, gas support, open-water and full-overhead zones.
• ›Sala Silvergruva — project-managed industrial archaeology; guest teams remain on approved routes, with deeper sectors requiring site-specific progression.
• ›Långban — deep technical mine exploration to roughly 100-115 m levels in a ~370 m-deep historic mine.
• ›Nordmarksberg — documented 60-70 m-level exploration and industrial archaeology.
• ›A-gruvan — nationally established but deliberately low-profile; sensitive location/details are not reproduced.
• ›Utö and other Bergslagen workings — project or case-by-case only; existence of flooding does not imply public access.

• ›Bo Lenander — recognised the Dolinsjön entrance in 1979.
• ›Nicklas Myrin and Johan Utas — key leaders in the modern Bjurälven winter-expedition era.
• ›Mats Fröjdenlund — long-term Bjurälven leader and public voice for exploration/3D work.
• ›Micke Tilja — cave diver/photographer and major Bjurälven documentarian.
• ›Anders Etander — technical/cave/mine instructor, Tuna-Hästberg dive manager, active across organised Swedish mines.
• ›Jonas Pavletic — key Sala Silvergruva Dykarklubb figure.
• ›In Water Under Land (IWUL) — mine exploration and 3D-photogrammetry team.
• ›Sveriges Speleologförbund (SSF) — national speleological federation supporting research access and documentation.

• ›Expedition Bjurälven — project overview, cave details and history
• ›Jämtland County Administrative Board — Bjurälven reserve and permit rules
• ›SGU — Bjurälven karst landscape and Korallgrottan context
• ›Lummelunda Cave / Gotland County Administrative Board — cave and reserve information
• ›Äventyrsgruvan — current mine-diving information and common mine rules
• ›Swedish Diving Federation — Grott- och Gruvdykning 2025
• ›Sala Silvergruva Dykprojekt — current FAQ and project access
• ›Värmlands Museum — Långban underwater documentation
• ›Nordmarks Hembygdsförening — Nordmarksberg history and exploration
• ›In Water Under Land — mine exploration and photogrammetry
• ›Swedish public-service reporting — Sala and Tuna-Hästberg incident investigations