Disused 45-metre lead mine headframe at Korsnäs, Ostrobothnia, now the centrepiece of a heritage visitor area.
Gruvtornet is the 45-metre steel headframe of the former Korsnäs lead mine (Korsnäs gruva) in the municipality of Korsnäs, southern Ostrobothnia, Finland. The first lead ore discovery in the area was made in 1950 when a limestone block containing galena came to light during ditch-digging. Construction of the mine complex began in 1958, when the tower was erected, and lead ore extraction under Outokumpu Oy began in 1961.
Low world market prices caused a temporary closure in 1962–1964, after which mining resumed. The mine employed approximately 90 miners and 35 white-collar staff, with a total workforce including contractors of around 162 persons, and produced on average about 100,000 tonnes of ore per year. All lead ore had been extracted by 1973, when Outokumpu closed the operation.
Underground workings, flooded to depths of some 267 metres, remain beneath a nearby lake. The headframe and several surface buildings survive, and the site is managed as Korsnäs Gruvcenter, a heritage destination developed by the local Korsnäs Mine Center association.
The first indication of lead mineralisation at Korsnäs came in 1950, when local prospectors submitted a sample from a limestone block that had been exposed during ditch-digging. The ore body was subsequently localised at Svartören in Korsnäs in 1955 on the basis of those samples.
Construction of the mine infrastructure began in 1958, at which time the distinctive 45-metre headframe — Gruvtornet — was erected. Lead ore extraction commenced in 1961 under Outokumpu Oy, Finland's principal state mining company. However, depressed world market prices for lead ore forced an interruption: the mine was closed in 1962 and did not reopen until 1964. From that date extraction continued without further interruption until all workable lead ore had been recovered. During its active years the mine employed approximately 90 miners and 35 administrative staff, with the total workforce including contractors reaching around 162 persons. Annual ore output averaged approximately 100,000 tonnes.
At least one year of activity beyond the completion of lead extraction was spent processing copper ore imported from the Långbacken deposit in Petalax through the Korsnäs beneficiation plant before all operations ceased definitively in autumn 1973, when Outokumpu closed the entire installation.
The underground workings extend beneath a lake adjacent to the surface site. Divers have reached a depth of 60 metres within the flooded shafts and tunnels, which descend in total to more than 267 metres. The site, covering six hectares, contains the headframe, the beneficiation plant, and various surviving pithead buildings, and is owned by Korsnäs municipality.
From the early 2010s the Korsnäs Mine Center association developed the area as a heritage visitor site — Korsnäs Gruvcenter — with a walking trail, information panels, and an escape-room attraction in a surviving office building. The Gruvleden nature trail along the former mining area was later closed temporarily due to elevated lead levels in the ground. Plans have been discussed over a number of years to install an observation lift in the headframe, which would afford views over the southern sections of the nearby Kvarken UNESCO World Heritage Area, but funding for this had not been secured as of 2020.