The Geological Survey of Finland carried out detailed exploration in the Talvivaara area from 1977 to 1983. Outokumpu Plc. was granted mining licenses to the Talvivaara deposits in 1986 and continued the work in the late 1980's and early 1990's.
The resource was found to be large but of relatively low grade, and it was concluded at the time that the exploitation of the deposits was not economically viable using conventional metal extraction techniques.
Meanwhile, bioleaching was still a rather young technology and considered to be too risky for large scale operations at the time.
The resource remained unexploited until Outokumpu Plc., as part of its strategic decision to withdraw from mining activities, sold the rights to mine the Talvivaara deposits to Talvivaara Mining Company Plc in February 2004. Talvivaara Mining Company Plc was at the same time assigned the right to use all exploration data and research documentation relating to bioheapleaching, which had been in development at Outokumpu since 1987.
Since acquiring the rights to mine the Talvivaara deposits, the Group has actively pursued the development of the Talvivaara deposits. In March 2007, the bankable feasibility study, which contains detailed estimates of all material capital and operating expenditures expected to be incurred in connection with constructing and operating the mine, was approved. The Group has also obtained an environmental permit and other material permits required for the ongoing mining operations.
Construction of an on-site pilot heap was started in June 2005 and initial bioheapleaching commenced in August of that year. A metals recovery trial using leach solutions was then run from March to September 2006.
In November 2005, a first round of financing from institutional and strategic investors raised €7 million which enabled completion of a feasibility study. This was followed by a second fundraising in October 2006 which raised a further €33 million to accelerate development.
The Group submitted the application for an environmental permit in March 2006. The permit was granted on 29 March 2007 followed by the commencement of the construction phase of the project.
Between Aprill 2007 and October 2008 during the 18 months followingn the start-up Talvivaara successfully produced first metals at the Sotkamo mine in October of 2008 as planned.