Active deep underground polymetallic mine at Kristineberg, Malå Municipality, with ore production since 1940; now reaching depths of 1,350 metres.
Kristinebergsgruvan is an underground mine producing zinc, copper, lead, gold and silver, located in the village of Kristineberg, Malå Municipality, Västerbotten County, Sweden, at the westernmost extent of the Skellefte mining district. Subcropping mineralisation was identified in 1918 through geophysical surveys following the discovery of sulphide-rich boulders; Kristineberg was the first deposit in the Skellefte district confirmed by electrical geophysical prospecting. Further investigation took place between 1930 and 1934, and the shaft was sunk to the 90-metre level in 1935, with a decision to begin mining taken in 1937.
The first ore left for Boliden in 1940. Initial workings comprised four small open pits prior to full underground development. A mill and concentrator operated on site until 1991, when processing was transferred to the Boliden Area process plant at Boliden village, to which crushed ore is now trucked approximately 92 kilometres.
The mine has reached depths of approximately 1,350 metres and remains in active production under Boliden AB, with the satellite Rävliden deposit beginning production in 2024 to extend mine life to at least 2033.
Kristinebergsgruvan occupies the western end of the Skellefte district, a Paleoproterozoic volcanic-hosted massive sulphide belt in Västerbotten, northern Sweden. The deposit is hosted within a wide zone of sericitised and chloritised supracrustal rocks, originally quartz- and feldspar-rich acid volcanics. The ore zone strikes east–west and dips between 45 and 70 degrees south, with a plunge of approximately 45 degrees south-west. Two major ore lenses, A and A3, are present, consisting of mixed sulphides containing gold, silver, copper, zinc, lead and sulphur; zinc is the dominant value metal. The deposit is described as one of the oldest found in the Skellefte district and the first confirmed by electrical ore prospecting.
Subcropping mineralisation was identified in 1918 following geophysical surveys and the discovery of sulphide-rich boulders at surface. Further investigations were conducted between 1930 and 1934. A shaft was sunk to the 90-metre level in 1935, and a decision to begin mining was taken in 1937. The first ore shipment to Boliden's facilities took place in 1940, marking the beginning of the mine's operational history. Initial workings were carried out as four small open pits prior to the development of underground infrastructure.
A mill and concentrator operated on the mine site until 1991, when it was decommissioned. During this period tailings were deposited in five facilities in the valley below the mine. Four of the five tailings facilities have since been closed and reclaimed or are being reclaimed; Magazine 4 continues to function as a settling pond following water treatment with slaked lime. From 1991 the mine's ore was trucked to the Boliden Area Operations Process Plant (BAOPP), approximately 92 kilometres distant, for flotation treatment, before further processing of concentrates at the Rönnskär smelter.
Kristineberg was historically connected to Boliden by an aerial ropeway passing through Rakkejaur. This ropeway formed a key transport link in the early decades of the mine's operation, before road haulage replaced it.
The central shaft was progressively deepened. It reached the 790-metre level in a development phase which also placed a crusher at the 690-metre level and a skipping station at the 751-metre level. A main ramp was subsequently built to connect the 690-metre level to the surface. A later decision was taken to extend the ramp down to the 1,100-metre level.
New ore zones were discovered at depth through ongoing exploration. The Einarsson Zone (E-Zone) was intersected during development of the deeper ramp. A decision was taken to build a cyanide leach facility at the Boliden Area process plant, commissioned in 2001 at a cost of SEK 100 million, to treat gold-rich ore from the Einarsson Zone. Production from the Einarsson gold–copper zone began thereafter. Subsequent intersections included the J-Zone (copper–gold–zinc), the K-Zone (zinc, which entered production), the M-Zone, and the Silver Zone, along with Tommy, Raimo and Koppar Klumpen zones at various levels between 800 and 1,350 metres. Total ore produced since the mine opened through 2020 amounted to 22.4 million tonnes grading 1.0 per cent copper, 3.64 per cent zinc, 0.24 per cent lead, 1.24 g/t gold and 36 g/t silver.
Boliden maintains active exploration at Kristineberg. The Rävliden North deposit, a satellite deposit accessed by a five-kilometre decline from the Kristineberg industrial area, began test mining in 2023 and production ramp-up in 2024. This project is projected to extend mine life at Kristineberg to 2033. The Rävliden North deposit is broadly similar in character to Kristineberg but is amenable to long-hole stoping methods between depths of 300 and 1,000 metres. The mine currently extracts ore at depths of up to approximately 1,350 metres and the surface headframe and associated pithead infrastructure remain in place. Ore is trucked 92 kilometres to the Boliden Area process plant, then zinc and lead concentrates are transported to Boliden smelters in Norway and Finland or to external customers.