The 3,200 ha mining property is located in northern Finland above the Arctic Circle some 142 km north-northeast of Rovaniemi, the capital of the province of Lapland.
The first report on ultramafic rocks at Kevitsa goes back to the 1930s. In 1973 the first nickel-bearing float sample was discovered, followed by an initial diamond drilling in 1984 that intersected only low-grade pyrrhotite. Subsequent ground geophysical surveys - magnetic, gravity and electromagnetic - till geochemical sampling and drilling delineated a mineral resource to a depth of 500 m.
The project will be developed as an open pit mining operation. Some 4.5 Mt of ore per year will be mined, resulting in production of nickel and copper concentrates containing 19 million pounds of nickel and 31 million pounds of copper per year. Proven and probable reserves in the proposed open pit total 66.8 Mt to 400 m depth, giving a mine life of 15 years at an average strip ratio of 2.34:1.
The overall site layout calls for a process plant and workshops, stores, canteen, waste rock piles and tailings and return water dams.
Process design consists of conventional: crushing, SAG and ball milling, sequential copper and nickel flotation with thickening and filtration of the copper and zinc concentrates.
As of 2006, estimated operating costs totaled 7.37-8.87 euro/t mined or processed.
The Koitelainen Natura 2000 area must be protected from the potential impacts of mining operations and the design and placing of buildings, haul roads and access roads.
Commercial production is expected in 2012.
The northernmost point of Finland's electric railway is the city of Rovaniemi, which is also the capital of its northernmost province: Lapland. It boasts a population of almost 60,000, a university, an Arctic museum, the residence of Santa Claus and it is also the home of McDonald's most northern branch. It is also linked to Helsinki by roads and planes.
Kevitsa is located some 142 km north-northeast of Rovaniemi on the E75 road which leads to the village of Petkula from where an 8 km long forest road could be followed to reach the future Arctic mine site.
The flat Kevitsa mine site is located on a 220 to 240 masl boggy plateau surrounded by 350 m high local hills covered with pine forest. The original forest at Kevitsa was cut down decades ago.
Bedrock outcrops on the hills but is generally masked by a 1 to 5 m thick layer of sandy clay till. In boggy land the till is overlain by a 1 to 5 m thick peat layer.
The climate is Arctic. October to April has negative average temperatures with January being the coldest with an average of -14.1 degrees Celsius. Half of the precipitation falls during this period as snow. The summer months warm up fast with July being the warmest with an average of 14.3 degrees Celsius. There is no permafrost in the area.
The Petkula area is renowned for its hunting, fishing, picking berries, mushrooms and bird watching activities. Reindeer herding is still a mainstay of local economy.
The Kevitsa Intrusion, which hosts the namesake deposit, is situated within the Baltic Shield. Intrusive activity towards the end of the Archaean generated an abundance of layered intrusions.
The intrusion measures some 3.5 km north-south by 5 km east-west, it has a roughly circular outcrop/subcrop and comprises basic olivine pyroxenites and metaperidotites in the northeast, gabbro in the west and central areas and granophyre primarily in the south. It is characterized by internal layering defined by changes in petrologic composition.
The deposit is contained within the olivine-pyroxenite of the ultramafic zone of the Kevitsa Intrusion. The zone contains up to 5% sulphide, the majority of which occurs as granular masses interstitial to the cumulate silicate mineral grains.
Mineralogy comprises largely olivine and orthopyroxene. The finely disseminated sulphides are 100-500 mm in size, and consist of pyrrhotite, troilite, chalcopyrite, pentlandite, cubanite, millerite and heazlewoodite.
The main ore type forms a zone up to 300m thick in the centre of the deposit. It has a high sulphide content, high nickel and copper grades, significant PGE and gold contents and high Ni/S, Ni/Co and Ni/Cu ratios. The nickel-PGE type has a higher Ni/Co ratio than the main type, and has a tendency towards lower sulphur and copper contents.
Mineralization outcrops on surface and an oxidized zone of a few meters above the water table has been noted.
As of April 2006, proven and probable mineral reserves stood at 66.8 Mt at 0.295% nickel, 0.427% copper, 0.014% cobalt, 0.141g/t gold, 0.196g/t palladium and 0.303g/t platinum.
Kevitsa mine is designed as a conventional open pit mining operation that would contract mine approximately 4.5 Mt of ore per year.
An average 2.34: 1 waste to ore stripping ratio was estimated over the 15 years mine life. One additional year would be necessary for pre-stripping.
The optimal pit shell has a 900 by 700 m oval shape and a 400 m final depth. At its steepest point the pit wall has an angle of 53.8 degrees.
The process design consists of conventional: crushing, SAG and ball milling, sequential copper and nickel flotation with thickening and filtration of the copper and zinc concentrates.
Metallurgical test work tested both selective flotation for producing separate copper and nickel concentrates, and bulk flotation. In bulk flotation at alkalic conditions high metal recoveries were reached: Cu 94.9 %; Ni 84.4 %; Pt 78 %; Pd 90 %; and Au 77 %. The bulk concentrate grades were then 6.06 % Cu and 3.65 % Ni.
Tailings disposal at Kevitsa will be in separate low and high sulphur tailings ponds of downstream earthfill construction, with the latter having a bentonite cover to the embankment. Tailings will be deposited to a total thickness of 22 m and the maximum dam height will be 26 m.
Ore processing will generate 12% nickel and 24.5% copper concentrates containing 7,893 t of nickel and 12,882 t of copper per year.
Environment and community
The Arctic Koitelainen Natura 2000 conservation area lies to the east and has to be protected from the potential impact of mining operations and the design and placing of buildings, haul roads and access roads.
The nearest water resource is Satojarvi Lake which is considered to be valuable as a migration resting place for birds. All water effluents would be directed away from the nature conservation area.
A 30 year mine closure, rehabilitation and monitoring plan was taken into account in order to satisfy environmental requirements.
Mine construction and operation will have some influences on local reindeer herders' practices and these will also be mitigated.