Sweden

Boliden Area Operation

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Overview

Mine TypeUnderground
Commodities
  • Zinc
  • Copper
  • Lead
  • Gold
  • Silver
  • Tellurium
Mining Method
  • Cut & Fill
  • Room-and-pillar
  • Longhole open stoping
  • Bench stoping
  • Drift & Fill
  • Longitudinal open stoping
  • Avoca
  • Cemented rockfill
  • Unconsolidated hydraulic fill
  • Unconsolidated rockfill
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Mine Life2029
ShapshotThe Boliden Area, which includes the underground mines in Renström, Kristineberg and Kankberg, is where the first gold deposit was discovered, laying the foundation for Boliden’s operations.

With the exception of Kankberg, complex sulphide ores, which contain zinc, copper, lead, gold and silver, are produced by all the mines. The area also has a concentrator and a leaching plant for gold and tellurium production. The tellurium that is mined in Kankberg is used, among other things, for solar cell production.
Related Asset

Owners

SourceSource
CompanyInterestOwnership
Boliden AB 100 % Indirect
Boliden Mineral AB (operator) 100 % Direct
Boliden Area Operation (Renström, Kristineberg, and Kankberg mines) is 100% owned by Boliden Mineral AB.

Contractors

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Deposit type

  • Porphyry
  • Vein / narrow vein
  • Breccia pipe / Stockwork
  • VMS

Summary:

Kankberg Geology The Kankberg Mine lies within the eastern part of the Skellefte mining field, one of the most important mining regions in Sweden, where Boliden has been active since the 1920s. It’s significance in relation to 52 other known deposits in the field is shown in Figure 11 from a paper by Allen et al (1996) that describes the marine volcanic arc setting of these Zn-Cu-AuAg polymetallic massive sulfide deposits, vein Au deposits and porphyry Cu-Au-Mo deposits. The host rock in the Kankberg area is dominated by volcanic rocks of primarily dacitic and rhyolitic compositions forming quartz-feldspar porphyritic, rhyolitic and dacitic rock types. The felsic magmas forming these volcanics intruded as shallow (subvolcanic) dykes and sills and extruded as lavas at the surface where they mixed with sediments and mass flows derived from volcanic slopes. The volcanism initiated a convection of solutions through the rocks. These solutions dissolved and transported minerals and metals to sites of deposition. After the major volcanic period had ended the area was subsequently deformed and folded. This resulted in a dominantly vertical trend of the rocks and structures. At a later stage, brittle deformation took place. Fractures and fissures were intruded by mafic magma forming basaltic and andesitic dykes, which are common in the Kankberg area. Mineralization Gold mineralization is hosted in a complex mix of volcanic rocks consisting primarily of quartz-feldspar porphyry, volcaniclastics and breccias. The host rocks are strongly altered by silicification, andalusite ± topaz alteration and to a varying degree sericitization. The strong alterations form a highly competent body, which is surrounded by dacites. The contact zone is characterized by sericite ± chlorite alteration associated with pyrite ± pyrrhotite. The economic mineralization is contained in ‘metallic’ minerals primarily located within the quartz-andalusite ± topaz alteration. It includes fine-grained native gold alloyed with silver at proportions of between 0 to 20%. More commonly, gold occurs as gold-tellurides including petzite (Ag3AuTe2), calaverite (AuTe2) and sylvanite (AuAgTe4). Another common telluride is tellurobismuthite (Bi2Te3). Several more telluride minerals have been identified through microscopy. Renstrom Geology The rocks in the Skellefte district were formed approximately 1.9 Ga during a period of active volcanism. The felsic magmas intruded as shallow (subvolcanic) intrusions (dykes and sills) at and close to the surface, where they mixed and mingled with wet sediments and mass-flows derived from volcanic slopes resulting in hyaloclastic brecciation and peperites. The active volcanic region also initiated a convection of solutions within the deposited package which enabled the dissolution and transportation of metals and minerals. These solutions also altered the rocks both physically, through (hydro-) brecciation and fragmentation, and chemically resulting in the heavily altered rocks present today. After the main volcanic period, regional deformation took place within the Skellefte district. The brittle deformation accommodated for fractures and fissures, which would be filled by mafic magmas forming andesitic and basaltic dykes. The Renström area is located 15km west of Boliden, in the eastern part of the Skellefteå district. The Renström area has a volcanically complex and multiply deformed rock sequence. Rock types include a large range of basaltic andesite to rhyolite volcanic facies. Juvenile basaltic andesite, dacite and rhyolite volcanoclastic facies are particularly abundant and these have been intruded by numerous basaltic, andesitic dacitic and rhylitic sills and doms. The area has two main generations of folding with a complex interference pattern, and several generations of faults and intrusions. The Renström area is one of the most intensely mineralized parts of the Skellefte district and the Renström deposit is one of the most important deposits due to its size (>10 million tonnes), grade (high Zn, Au, Ag values) and metallurgical characteristics (medium grained; low arsenic and antimony contents). The ores in the Renström deposit are associated with strong chlorite, dolomite, sericite and silica alteration. Mineralization The Renström mineralization consists of several smaller lenses, which are all characterized by massive to semimassive pyrite-sphalerite dominated ores with subordinate massive to semimassive pyrite-chalocopyrite ore and local stringer-type pyrite-chalocopyrite±pyrrhotite mineralization. The main ore minerals are pyrite, sphalerite, galena, chalcopyrite, pyrrotite and arsenopyrite with minor tetrahedrite-tennantite, other sulphosalts, electrum and amalgam (Helfrich, 1971; Kläre, 2001). Ores in the Renström area have higher zinc, gold, silver and lead contents and lower sulphur and arsenic content than most volcanic-hosted massive sulfide ores in the Skellefte district. Kristineberg Geology The Kristineberg Camp is located on the western extent of the Skellefteå district. The Skellefte district is a Paleoproterozoic (1.89 Ga) Volcanic sedimentary area Located in Västerbotten, northern Sweden. The area stretches roughly 100 km from the village of Kristineberg in the west to the village of Boliden in the east. The Skellefte district hosts more than 85 VHMS deposits, of which 26 have been, or are currently hosting mining operations. The VHMS deposits of the area are mostly hosted in the upper parts of a volcanic sequence of intermediate to felsic juvenile volcanoclastic rocks, sub volcanic intrusions and lavas. These rocks together form the Skellefte group, which in turn is the lowest stratigraphic sequence in the Skellefte district. (Allen, Weihed, & Svenson, 1996). Mineralisations Mineralisations of the Kristineberg Mine are hosted in steeply-gently dipping Chlorite Schist lenses, with a gentle plunge towards the SW. The mineralisation generally appears as two “arms”, the southern arm consisting of the B-, E-, J-, K-, M-,and Ag-Zones as well as the Raimo and Tommy mineralisations. On the northern “arm” lies the L-Zone and A-Zones. Mineralisations can be generally split into two types: • Chlorite Schist hosted mineralisations, and • Ag-Pb “remobilised” mineralisation. Chlorite schist hosted mineralisation generally contains sulphide mineralisation that is semimassive to massive in nature with variable abundances of economically important minerals: chalcopyrite (CuFeS2), sphalerite ((Zn, Fe)S) and galena (PbS), with minor silver and gold. The schists themselves contain variable amounts of muscovite, quartz, chlorite, phlogopite, biotite, cordierite, andalusite, pyrite and magnetite. The chlorite schists appear as lenses within colloquially named “quartzites” which are hypothesised to be highly altered rhyolitic to dacitic rocks (Barrett & MacLean, 2000). Chlorite, cordierite, sericite and andalusite as well as quartz overprint the original rock textures making primary rock identification difficult. The “remobilised” Ag-Pb type is hosted within silicified cordierite and chlorite quartzites. Five silver bearing minerals are present within the Ag-Zone; freibergite ((Ag, Cu, Fe)12(Sb, As)4S13) being the dominant one with minor amounts of hessite (Ag2Te) often present. High silver grades are often present in narrow zones associated with galena veins or fracture fillings.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityProductUnits2022202120202019201820172016
Zinc Metal in concentrate kt 00000000576670
Zinc Concentrate kt 0000000000103123129
Copper Metal in concentrate kt 0000556
Copper Concentrate kt 00000000202023
Lead Metal in concentrate kt 0000334
Lead Concentrate kt 00000091312
Gold Metal in concentrate oz 0000000000000000000088,46179,61572,693
Silver Metal in concentrate koz 00000000000000002,3202,5972,730
Tellurium Metal in concentrate kg 0000000000000000000044,64134,97938,680

Operational metrics

Metrics202220212020201920182017
Ore tonnes mined 000000000000000000000
Waste 000000000000
Total tonnes mined 00000000000000
Tonnes milled 00000000000000001,947 kt2,065 kt

Production Costs

CommodityUnits202220212020201920182017
C1 cash costs Zinc USD 000 000 000 0.75 / lb   0.78 / lb   0.79 / lb  
C1 cash costs Copper USD 000 000 000 1.47 / lb   1.53 / lb   1.43 / lb  
C1 cash costs Gold USD 000 000 000 715 / oz   692 / oz   686 / oz  

Financials

Units202220212020201920182017
Capital expenditures M SEK  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 632   440  
Revenue M SEK  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 2,361   2,612  
Operating Income M SEK  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 756   868  

Heavy Mobile Equipment

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AV - Autonomous

Personnel

Mine Management

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EmployeesYear
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