Closed zinc-lead sulphide mine at Bleikvasslia, Hemnes, Nordland, shut in 1998 after four decades of production; site subject to ongoing heavy metal drainage concerns.
Bleikvassli Gruber is a former underground zinc-lead mine situated west of Røssvatnet in Hemnes municipality, Nordland county, northern Norway. The ore deposit, a SEDEX-type stratiform massive sulphide body containing zinc, lead, copper, and silver, was first identified in 1916 or 1917. Following investigations in the late 1920s and again during and after the Second World War, trial production began in 1947 and full commercial mining in 1957.
Over approximately four decades of operation, the mine extracted more than five million tonnes of ore grading roughly four percent zinc, two percent lead, and minor copper and silver. Operations ceased in 1997 and 1998 after a combination of terrain subsidence, water ingress, and exhaustion of economically viable ore reserves brought the company to close the mine. Post-closure, heavy metal drainage from the site into the Bleikvasselva river has remained a significant environmental concern, and ground instability events have required the evacuation of nearby residents on at least one occasion.
The Bleikvassli ore deposit was first discovered in 1916 or 1917 — sources give slightly different dates, with the earliest ore extraction apparently taking place at that time. Formal investigation campaigns were carried out in 1928–1929 and again during the Second World War and its aftermath. A topographic and drilling plan of the site was produced by the Norges geologiske undersøkelse in 1942.
Trial mining began in 1947, and the company Bleikvassli Gruber A/S established full-scale production in 1957. The deposit is a stratiform massive sulphide body classified by geologists as SEDEX-type, hosted by Proterozoic pelitic, quartzo-feldspathic, and amphibolitic rocks of the Uppermost Allochthon of the Scandinavian Caledonides. The orebody forms two connected lenses — a southern and a northern — spanning at least 1,500 metres of strike length, dipping moderately to steeply westward and plunging to the north-east.
The operating mine developed 40 levels and approximately 25 kilometres of drifts, raises, and shafts accessed through a portal and ramp system rather than a surface headframe arrangement. At peak production in the 1980s, the mine extracted approximately 180,000 tonnes of raw ore per year. Production through to the mid-1990s is recorded at around 191,000 tonnes per year, yielding zinc and silver-bearing lead concentrates that were shipped from Andfiskå near Mo i Rana.
Total production over the operating life of the mine reached approximately five million tonnes grading 4.0 percent zinc, 2.0 percent lead, 0.15 percent copper, and 25 grams per tonne silver. In autumn 1997, significant water ingress caused by terrain subsidence and underground falls forced the suspension of regular mining operations. The company board formally resolved to close the mine in August 1998, citing the failure of extensive prospecting to locate further economic ore reserves.
Norwegian Geological Survey estimates prepared at the time of closure indicated residual resources of approximately 720,000 tonnes at elevated zinc, lead, and silver grades, though these figures were not brought to full international reporting standards. After closure, the mine site became a source of heavy metal contamination to the Bleikvasselva watercourse, with research conducted by Norsk institutt for vannforskning in 2009 recording very high concentrations of heavy metals in the upper parts of the catchment attributable primarily to drainage from the former mine area. Regulatory responsibility for remediation remained under discussion between the former operating company, Bergvesenet (the Norwegian Directorate of Mining), and environmental authorities.
In June 2013, a further ground stability incident occurred when an area of approximately seven to eight dekar outside the former mine entrance subsided by 20 to 30 centimetres overnight and a crack propagated through the terrain. Several homes in the immediate vicinity were temporarily evacuated. The mine site and its associated exploration licences were subsequently acquired by EMX Royalty Corp. and then by Norra Metals Corp. (TSX-V: NORA), which conducted technical reviews and three-dimensional geological modelling of the historic data with a view to future exploration but had not resumed mining as of the mid-2020s.