Uhlun kaivos

Two adjacent water-filled pits sit within the same red-granite quarry complex in inland Vehmaa, and the standard programme works across both. The main pit drops on vertical, straight-walled granite to about fifteen metres on bedrock, where preserved early-twentieth-century steam engines and assorted abandoned quarry equipment lie on the floor — left in place when work ended in the early 1960s and the dewatering pumps were removed. The secondary pit reaches about twenty-five metres and historically held a dark suspended-sediment layer below about twenty that killed visibility even with strong lights, gradually settling toward the bottom over the years. There is no current and no surge in either pit, and bottom visibility on the wall sits around five to ten metres. The shallow main pit suits OW skills and the steam-engine pass; the deeper pit is the AOWD-deep and computer-multilevel venue, with course profiles regularly stepping divers down to twenty-five metres.

Uhlun kaivos is a steam-engine graveyard set inside a red-granite quarry — a piece of early-twentieth-century industrial archaeology you swim through rather than read about. Granite quarrying began here in 1900, and when work on the main pit ended in the early 1960s the heavy machinery was abandoned in place and slowly drowned by groundwater after the pumps came out. The result is a freshwater dive that is unambiguously a working quarry rather than a sunken-on-purpose attraction: steam-era engines, support gear, and miscellaneous quarrying iron rest on bedrock at fifteen metres, and the surrounding granite walls hold the turquoise tone of the Uhlu stone above. The site is actively dived today as a club dive park by an association of Finnish dive clubs that rent the quarry from the landowner, which is what keeps the site coherent and the machinery on the bottom rather than salvaged.

Uhlun kaivos is run as a lessee-association dive park, not a publicly bookable site. An association of around fifteen Finnish dive clubs jointly rents the quarry from the landowner and access is reserved for their members; non-lessee outsiders are not authorised on the site, and a public 2024 statement by a landowner-associated commenter reiterates that point. The site is not on any commercial dive centre's regular schedule and not open to walk-up access. Visiting divers should arrange the dive in advance through a lessee-club host rather than approaching the quarry directly. Out of respect for the lessee clubs, specific gate procedures, named contacts, and precise dive-entry coordinates are kept off public pages — coordinate the practical details directly with the host club. Drysuit is the working suit for serious dives in any season; in winter, ice diving runs as a club programme with surface support and rope-signal protocols.