Nickel ore was discovered in Kotalahti in the 1950s, and the Outokumpu Group decided to open a mine. This took place in July 1957.


1959 to 1960

Harjavalta celebrated the topping out ceremony of the nickel plant on 06 August 1959. Electrolysis cells were connected to the power circuit on 04 May 1960, which can be considered the first production day of the plant. On that same date, nickel began to grow into metallic cathode coating for the first time.


The efficiency of air oxidation leaching was increased quickly during the first years: in the spring 1961, there was one reactor, but in the spring 1963 there were already six. Similarly, there were initially fourteen electrolysis cells, and these had increased to 32 by September 1961.

  NN historia 1959
Building works in 1959.

1962 to 1964

The first control room was finished in 1962. During the first years, the entire production process took place in one building, but the plant was first extended in 1964 when nickel cutting, packing and storage processes were transferred to a separate building.

In the early summer 1962, we started to extract the cobalt content of the nickel solution in the form of a separate purified by-product, the so-called cobalt cake. During that same summer, we started to anneal nickel cathodes in salt bath ovens to reduce internal stress and to modify crystal structures.
February 1963 saw the introduction of a procedure to extract copper from the solution in the leach circuit, and the mill drum grinding bodies were exchanged into metal balls in the winter 1964.

Production quantities

The original annual production target of 2,500 tonnes was approached already in 1962, and by the end of the first five-year cycle, at the end of 1964, the annual production was nearly 3,000 tonnes. The annual production already exceeded 3,700 tonnes towards the end of the decade, in 1969.


The annealing of nickel cathodes started 1962.



1970 to 1972

The favourable trend in the nickel market and a good supply of raw material allowed us to put an expansion plan in motion at the turn of the decade: a new electrolysis hall was added to the first one, taking the number of nickel cells to 88. The old plant grew from 108 metres to 162 metres.


Metal ball  drum grinding in the 1970’s.



The electrolysis process abandoned the old methods of cathode annealing, starting sheet varnishing and electrolytic corrosion of seed plates.

1976 to 1978

The increase of nickel cell equipment improved the production capacity, and a cathode bundling machine replaced manual bundling in 1978.

Production quantities

The period from 1970 to 1972 saw annual production reach 10,000 tonnes. By the end of the decade, the amount was nearly 13,000 tonnes.


  NN historia 1978
Expanded electrolysis hall in 1978.



1981 to 1982

The decade commenced with a plant expansion and renewal project: nickel production was expanded further, and the third electrolysis hall meant the plant now spanned some 204 metres. The nickel cutting room was expanded in 1981.


Control room in the 1980’s.


The plant's wastewater purification process was expanded and strengthened by building a dedicated wastewater treatment plant.

Production quantities

The plant's first 100,000 tonnes of nickel production was reached in 1980, and a new annual production record was achieved in 1986: 18,000 tonnes.

  NN historia1987
200,000 tonnes reached in 1987.




As part of the Outokumpu Group's incorporation project, the copper-nickel group was transformed into a company called Outokumpu Harjavalta Metals Oy. The new company started its operations on 01 January 1990. At the beginning of the decade, new strategic plans for expanding nickel and copper production were drawn up.




1993 to 1996

Costing approximately 1.5 billion Finnish marks, the Harjavalta project was one of the largest investments carried out within the Group's history. As a result of this project, nickel production was doubled and copper production increased by 50 percent within one year.
The Harjavalta project allowed us to decrease environmental emissions significantly, making the company one of the foundries with the best environmental track record in the world. A 140-metre chimney was erected as a landmark of the project.
In addition to improving the control of sulphur, dust and water emissions, the company focused on cleanliness, landscaping and development of green areas.
A new product joined nickel cathodes in the metallic nickel product portfolio in 1995: nickel briquettes.


The company decided to focus on its own core expertise, the manufacturing of metals. All support functions were outsourced to other companies, which led to the formation of a completely new network cooperation model based on partnership. The introduction of the network model resulted in approximately 350 members of personnel transferring to new partner companies.

Production quantities

By 1999, the production of metallic nickel amounted to over 50,000 tonnes.



Reduction plants sintering oven in the 1990's

NN historia1995
Beginning of briquette production in 1995.






Outokumpu decided to discontinue all nickel business and sold the Harjavalta
plant to the American OM Group. This resulted in a new company called OMG Harjavalta Nickel Oy, which launched its operations by building a new chemical plant in Harjavalta. Nickel chemicals have been produced since 2002.


In time, OMG specialised in cobalt, and in the spring 2007 the company sold its nickel production operations to the Russian Norilsk Nickel Group.

  NN historia2001
The new chemical plant was opened in 2002.

2007 to 2008

During 2008 and 2009, Norilsk Nickel Harjavalta Oy allocated significant investments into new leaching and solution purification lines while Talvivaara nickel sulphide was introduced to the raw material selection. A new office building was also built in the western side of the Harjavalta Industrial Park (Suurteollisuuspuisto).

Production quantities

The total production reached 500,000 tonnes in 2000, and the milestone of a billion tonnes was celebrated in 2010.
Thus the first 500,000 tonnes was reached in 40 years, whereas the second 500,000 tonnes only took a decade.


  NN historia2010
The plant's first 500,000 tonnes of total production was reached in 2000 and the second 500,000 tonnes in 2010.

1960 1970 1980 1990 2000