Regional
The Kevitsa igneous complex lies within the CLGB located within the Precambrian Fennoscandian Shield. CLGB is a large area that consists of volcano-sedimentary rocks of Paleoproterozoic age and it is divided to seven stratigraphical groups (Räsänen et al. 1996). Which are from oldest to youngest: Salla, Onkamo, Sodankylä, Savukoski, Kittilä, Lainio, and Kumpu Groups Savukoski group supracrustal rocks that are enveloping Kevitsa intrusion. It is representing a major marine transgression dominated by dominated by black schists, phyllites, tuffites, mafic metavolcanics and the uppermost unit of ultramafic metavolcanics. According to Räsänen et al. (1996) these rocks are polyfolded, and thrusted resulting in overturning and structural repetition of the stratigraphy. There are three major ductile deformational events (D1-D3), simultaneous and later shear zones that are related to regional structures of the CLGB and are described in detail by Hölttä et al. (2007).

Local
Kevitsa igneous complex layered ultramafic-mafic intrusive rocks dated at 2058 ± 4 Ma (Mutanen & Huhma, 2001). The body of the intrusion extents to 2 km. The Kevitsa intrusions ultramafic units are on lower parts of the intrusion, which is overlain by the gabbroic rocks that are located on the South-West side of the ultramafics. There is a dunite unit in the middle of the deposit, which is disconcordant to magmatic layering as well in the bottom of the intrusion. Xenoliths are common in the ultramafics and within the ore body. They are variable in sizes and by composition; they typically are sedimentary, mafic or ultramafic. There are also several mafic dykes, in the intrusion, ranging in different ages but they are not very voluminous.

The Kevitsa area has undergone several tectonic and metamorphic events which are evident in the intrusion and in the country rocks (Hölttä et al. 2007). The NNE-SSW trending Satovaara fault, and other structures which are associated with it, are a structurally significant feature of the area. The Satovaara fault has deformed the eastern margin of the Kevitsa intrusion and within the deposit, there are smaller scale structures in similar trend.

Property
The Ni-Cu-(PGE) mineralization is located in the centre of the intrusions ultramafic rocks, and it is hosted typically by olivine websterite and its variants. In the broad sense, they can be described as clinopyroxene-dominated rocks with 0-30 % orthopyroxene, 5-25 % olivine and 0-10 % plagioclase. These rocks have very subtle visual and geochemical differences. The distribution and form of observed mineralogical and geochemical patterns are interpreted to represent multiple magmatic phases. There are no internal contacts to these pulses, but in many instances the base of one pulse (olivine websterite) will grade relatively sharply into the upper part of another pulse (plagioclase bearing olivine websterite). These layers are irregular in shape. Geochemically, differentiation within these pulses is most clearly demonstrated by Al2O3. It is proposed by Luolavirta et al. (2017), that the Kevitsa magma chamber was initially filled by stable continuous flow (“single” input) of basaltic magma followed by differentiation in an at least nearly closed system. In the following stage, new magma pulses were repeatedly emplaced into the interior of the intrusion in a dynamic (open) system forming the sulfide ore bodies. This model would explain the contrasting intrusive stratigraphy in the different parts of the intrusion, which likely is reflecting different emplacement histories.

The most widespread alteration in Kevitsa resource area is amphibole alteration of ferromagnesian minerals. The alteration is typically pervasive in style and has generally ‘”sharp boundaries” i.e. it does not grade out. Pervasively amphibole altered rocks are often accompanied by carbonate alteration: there can be millimetre- to metre-scale carbonate or carbonate-quartz veining. The first alteration phenomenon in Kevitsa, being also common, is the serpentine alteration where the olivine is replaced by dark serpentine. Magnetite was initially primary mineral but it is also associated with other alteration styles as veins like serpentine and carbonate alteration. Epidote alteration is associated with the rodingite dykes. Actinolite-chlorite alteration seem to be associated with the structures. Narrow actinolitic selvedges are also common on carbonate ± quartz vein margins, but these wider, green actinolite features are a distinctive vein set. Talc-carbonate alteration is strongly associated with the shear zones, late fractures and veins representing CO2 bearing fluids. The style can range from selective replacement of ferromagnesian species to pervasive alteration of the rock.

Mineralization
The known economic Ni-Cu-PGE mineralization is disseminated in style. While having some minor semi massive sulphide veins. Overall mineralization volume is irregular in shape, and it is cut by several faults which locally are offsetting the mineralization. The predominant mineralization type is Ni-Cu, comprising 95 % of the deposit. Within it, are mineralization domains, which can be separated by the distribution of Cu and NiS grades, and as well with the amount of PGE’s. The so-called Ni-PGE mineralization is in relatively small in volume.

The main economical minerals are chalcopyrite and pentlandite, but mineralogically speaking pyrrhotite is the most common sulphide. Typically, the sulphide grain size varies from fine to medium, and the grain aggregates are in the interstitial spaces of the silicates. In unaltered rocks the sulphide silicate grains are smooth and plain but in amphibole altered rocks the boundaries are irregular and serrated. Chalcopyrite generally occur as large anhedral grains, sometimes with cubanite and talnakhite, and as fine intergrowths within the gangue silicates. Pentlandite can be coarse-grained sub-euhedral, smaller intergranular grain bands between silicates and pyrrhotite, and “exolution flame” inclusions within pyrrhotite or pyrite of very fine grain size. In addition to pentlandite the nickel occurs in crystal lattice of some silicate minerals such as olivine, clinopyroxene and tremolite. The nickel in silicates is not recoverable in metallurgical process and therefore sulphide nickel is analysed by selective leach method. Pd and Pt typically occur as sulfosalts, such as arsenides and tellurides. According to Kojonen et al. (2008), over half of the PGE carrying minerals are as inclusions in amphibole, serpentine and chlorite. PGE carrying minerals which are related to sulphides occur mostly on sulphide grain boundaries, inclusions in sulphides or in late fracture fillings in pentlandite.

Mining methods
The Kevitsa Mine is an open pit mine operation using conventional truck and shovel operations. BKMOY owns a mining fleet and uses contractor to assist ore re-handling on the ROM pad for primary crusher feed. The onsite technical group supervises the contractor. Since April 2020, ore and waste mining is not assisted anymore by contractor services. The Kevitsa Mine commenced mining operations in autumn 2011, Hartikainen was then contracted to mine waste from stage 1. Mining has proceeded from initial excavation: stage 1 and stage 2 have been mined out and stage 4 mining has started in 2019. A strategic project will be held during 2021 in order to revise the life of mine with the feasibility of a possible expansion to an additional pushback, stage 5. The mining sequence broadly follows the sequence of events as follows:
- Grade control RC holes delineate the ore zones
- Blast patterns designed to reduce material throw and ore dilution - and a Blast Master planning process controls sequence of operation
- When possible, ore and waste blasted and mined separately as fragmentation requirements vary significantly. Blast movement monitoring is in place to minimize dilution and ore loss for mixed blasts
- Waste removed on each 12 m bench prior to the mining of ore, removal of waste in the successive cut-backs utilizes planned bulk systems of operation
- Trim blasts and perimeter blasting utilized to ensure pit wall profiles are cut to the correct angle and wall damage minimized
- Face shovels load rock into 225 t class trucks and ore hauled from the pit to the finger stockpiles which are integral part of the feed sequence to ensure ore blending can be achieved, haulage efficiencies can be maximized and operational flexibility enhanced at all times.

The mineral processing facilities at Kevitsa have undergone several modifications and an expansion since commissioning in 2012. In 2020, 9.5 Mtpa expansion project was commissioned, with a design capacity of 9.9 Mtpa.

The following unit processes comprise the Kevitsa Metallurgical facility:
- Primary crushing of ROM ore from the open pit (delivered by dump truck).
- Screening of the primary crushed ore to produce three products -coarse lumps and fines as feed to the AG mills, and a mid-size product for the pebble mill.
- Pebble storage bin 750 t live capacity. - Crushing of excess pebbles. ? A single stockpile of the mixed coarse and fine ore, with 15,000 t live capacity (16.7 h).
- Two 7 MW AG mills operating in parallel on material fed from the stockpile.
- The two AG mills operate in partial closed circuit with hydrocyclones, and with transfer of AG mill discharge slurry to the pebble mill by pump. Cyclone overflow is final product to flotation. - One 14 MW AG mill operating on material feed from stockpile and in complete closed circuit with hydrocyclones.
- A single pebble mill in closed circuit with cyclones to produce a final product (P80) size of 95 µm

The mineral processing facilities at Kevitsa have undergone several modifications and an expansion since commissioning in 2012. In 2020, 9.5 Mtpa expansion project was commissioned, with a design capacity of 9.9 Mtpa.

The following unit processes comprise the Kevitsa Metallurgical facility:

- Sequential flotation of copper and nickel concentrates.
- Copper flotation cleaning in four stages with regrind of scavenger concentrates product.
- Nickel flotation cleaning in five stages with regrind of the 2nd cleaner concentrate product.
- Flotation of sulphide rich concentrate from the nickel scavenger flotation tails to produce a low Sulphur content tailings with low acid forming capacity.
- Dewatering of Cu and Ni concentrates by thickening and filtration.
- Deposition of primary tailings into conventional (unlined) TSF.
- Deposition of sulphide rich concentrate into a dedicated lined tailings storage facility.