Sweden

Aitik Mine

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Overview

Mine TypeOpen Pit
Commodities
  • Copper
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Production Start1968
Mine Life2047
ShapshotAitik mine - the world’s most productive open-pit copper mine. In Aitik, ore haulage has been automated to a high degree, which provides conditions for large-scale production while also ensuring a safe workplace with good climate performance.

The mining area consists of Aitik and Salmijärvi open pits.

Boliden AB received an environmental permit for the Liikavaara satellite mine and expects to begin production at the end of 2023 year.

Owners

SourceSource
CompanyInterestOwnership
Boliden AB 100 % Indirect
Boliden Mineral AB (operator) 100 % Direct
Boliden Mineral AB owns 100 % of the Aitik mine.

Deposit type

  • Porphyry
  • IOCG
  • Hydrothermal

Summary:

The Aitik, Salmijärvi, and Aitik East deposits occur along a largely continuous elongate mineralized trend (the Aitik-Salmijärvi mineralization) stretching approximately 5 km along strike from north to south averaging about 500 m in width.

Host rocks of the mineralization at the Aitik deposit consist mainly of paleo-proterozoic (ca. 1.89 billion years) muscovite schists, biotite gneisses, and amphibole-biotite gneisses of volcanic and volcanoclastic origin, crosscut locally by diorite intrusive units. In places the diorite intrusive make up a significant proportion of the mineralized volume, but typically at lower than average grade. Foliation is well developed in the host rocks, dipping at about 50 degrees to the west. The mineralization is mainly structurally controlled and the main mineralisation; Aitik is delineated by a hangingwall thrust and a footwall shear. Main sulfide minerals in the deposit are chalcopyrite, pyrite and pyrrhotite, with significant accessory minerals including magnetite, molybdenite and sulfates. The entire package has been metamorphosed to amphibolite grade resulting in significant recrystallization and coarsening of both sulfide and silicate minerals. Late granite pegmatite dikes crosscut the mineralized host rocks and are generally weakly mineralized to barren.

Mineralization at the Salmijärvi and Aitik East deposits is very similar in nature to the Aitik deposit, with the exception that host rocks are strongly dominated by amphibole-biotite gneisses and local diorite. Sulphide mineralization in these deposits is dominated by chalcopyrite, pyrite and pyrrhotite, although at typically lower grade than in the Aitik deposit.

About 3 km to the east, on separate and volumetrically smaller mineralized trend, sits the paleoproterozoic Liikavaara Cu-(W-Au) deposit. At Liikavaara the mineralisation is hosted by quartz±tourmaline-calcite veins, calcite veins and aplite dykes that cross-cut biotite-amphibole schists and gneisses, steeply dipping to the west. The mineralisation is mainly chalcopyrite, pyrrhotite and pyrite, accessory minerals are sphalerite, galena, scheelite, molybdenite and magnetite. Liikavaara shows slight enrichments in Au, Ag and Bi.

Reserves

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Mining Methods

  • Truck & Shovel / Loader

Summary:

Aitik is a Palaeoproterozoic porphyry Cu-Au-Ag deposit, mined as open pit mine consisting of two active pits: Salmijärvi and Aitik. There are also plans to start a third open pit operation in Liikavaara, a satellite, Palaeoproterozoic Cu-(W-Au) deposit, situated 3 km east of Aitik. The mining in Aitik is commenced at three pushbacks designated S3, N6 and N7. Salmijärvi has one active pushback called SA2.

The ore is mined in two open pits along the same mineral deposit. The main pit is called Aitik and measures 4 km by 1.1 km at the surface, with the deepest point currently at 555 meters from the surface. In 2010, mining commenced in a second pit called Salmijärvi which has currently reached a depth of 285 meters below the surface, with a surface footprint of 0.9 by 0.6 km. The main pit will be expanded in all directions with five new pushbacks. Mining of pushback S3 in the southern part of the main pit started in 2016. Pre-stripping of pushback N7 commenced in 2019 to allow mining to start during 2020. No further expansions are planned for the Salmijärvi pit after the current pushback, which will be depleted during early 2023.

The ore and waste rock are blasted in 15-meter-high benches and are loaded on 300 tons capacity-size trucks by large rope shovels or hydraulic excavators. Ore from the deeper parts of the main pit is fed to one of two in-pit-crushers, while ore from pushbacks near the surface and the Salmijärvi pit is transported to a surface crusher situated between the two pits. Waste rock is separated in the loading process and hauled by trucks to dumps at the surface, where potentially acid-forming waste is dumped separately from non-acid-forming waste.

Holes for blasting are drilled with electric drills from Bucyrus and Atlas Copco. Hole depth: 16-17 m Hole diameter: 311 mm Drill attern: 7x9 m Between 200-300 holes are drilled for each round of blasting. A normal blast round produces around 700 000 tonnes of rock for extraction.

Boosters are loaded into the holes followed by emulsion explosives. Explosives: Emulsion explosives (Kemitti-610) from Forcit, about 1 tonne of explosive is used in each hole.

With the help of shovels from Bucyrus, P&H, Komatsu and wheelloaders from Caterpillar, the blasted rock is loaded on to trucks for further tranportation. The largest trucks, CAT 795F, holds about 313 tonnes. A bucket can hold 45 m³ rock (Komatsu 26 m³). The ore is transported to the crusher and the waste rock to a waste rock dumpsite. The machines are equipped with the positioning system Minestar.

Comminution

Crushers and Mills

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Processing

  • Flotation
  • Dewatering
  • Filter press

Summary:

The milled ore is sent for concentration through a series of froth flotation stages, namely, rougher, scavenger and four cleaning stages.

The milled ore is classified using a spiral classifier. Mineral separation is done by flotation and a copper concentrate is produced. The copper concentrate is dewatered using thickeners and air pressure filters. The precious metals are reported in the copper concentrate. The copper concentrate is trucked to on-site railway terminal and reloaded for further transport by rail to the Boliden Rönnskär smelter in Skelleftehamn.

The plant produces a final concentrate containing 20-23% copper with gold, silver and molybdenum. Copper recovery is at 85-95% while silver and gold is at 65% and 50%, respectively. Molybdenum is currently not being recovered.

Recoveries & Grades:

CommodityParameter2022202120202019201820172016
Copper Recovery Rate, % 90.5
Copper Head Grade, % 0.20.220.240.250.290.280.22
Copper Concentrate Grade, % 25.225.524.824.224.624.822.1
Gold Recovery Rate, % 58.6
Gold Head Grade, g/t 0.10.110.130.130.140.130.11
Silver Recovery Rate, % 75.3
Silver Head Grade, g/t 0.860.871.061.171.821.982.11

Production

CommodityProductUnits2022202120202019201820172016
Copper Metal in concentrate M lbs 000000000000219216157
Copper Concentrate kt 000000000000404394320
Gold Metal in concentrate oz 000000000000000000000101,28593,19768,127
Silver Metal in concentrate koz 000000000000001,7651,9891,820

Operational metrics

Metrics202220212020201920182017
Ore tonnes mined 43.3 Mt40,100 kt41,661 kt
Waste 30,472,000 t31,438,000 t
Total tonnes mined 73,768,675 t71,602,000 t
Tonnes milled 43,297 kt40,100 kt41,661 kt40,661 kt38,472 kt39,045 kt
Annual processing capacity 45 Mt

Production Costs

CommodityUnits202220212020201920182017
C1 cash costs Copper USD 0000000 0000000 0000000 0.76 / lb   0.77 / lb   0.82 / lb  
Net of By-Product.

Financials

Units202220212020201920182017
Capital expenditures M SEK 3,131  1,653  1,823   1,985   1,576   1,534  
Revenue M SEK 7,365  7,211  6,295   5,818   6,017   5,487  
Operating Income M SEK 3,076  3,281  2,296   2,149   2,494   2,073  

Heavy Mobile Equipment

HME TypeModelSizeQuantityStatusRef. DateSource
Drill Epiroc PV-351 Existing Dec 31, 2012
Excavator Komatsu PC 7000 1 Existing Jan 25, 2022
Excavator Komatsu PC 7000 1 Required Jan 25, 2022
Loader LeTourneau L2350 38 m3 1 Existing Jan 25, 2022
Loader Caterpillar 994F 18 m3 Existing Dec 31, 2012
Shovel P&H 4100C 45 m3 Existing Dec 31, 2012
Shovel (rope) Komatsu 4100 XPC 45 m3 Existing Jan 25, 2022
Truck (haul) Caterpillar 795F AC 313 t 14 Existing May 10, 2022
Truck (haul) - AV Komatsu 930E-5 290 t 11 Existing Oct 25, 2021

AV - Autonomous

Personnel

Mine Management

Source Source
Job TitleNamePhoneEmailProfileRef. Date
Environmental Manager Åsa Sjöblom 0970-729162 asa.sjoblom@boliden.com Jun 12, 2023
General Manager Thomas Sundqvist 0970-729011 thomas.sundqvist@boliden.com LinkedIn Jun 20, 2023
Mill Manager Andreas Berggren LinkedIn Jun 20, 2023
Mine Manager Patrik Gillerstedt LinkedIn Jun 5, 2023
Project Manager Johanna Lundin LinkedIn Jun 5, 2023
Technical Services Superintendent Åsa Bergstrand LinkedIn Jun 5, 2023

EmployeesYear
932 2022
770 2021
800 2020
750 2019
700 2018
650 2017

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