First indications of nickel (Ni), copper (Cu), cobalt (Co) and zinc (Zn) in the Talvivaara area were found in the early 1960s. Exploration for base metals continued during 1977-1983 by the Geological Survey of Finland ("GSF") and two polymetallic deposits, Kuusilampi and Kolmisoppi, were discovered. Between 1989-1992, Outokumpu focused on further geological work on the deposits and drilled 67 holes in the area.
Despite the considerable size of the deposits, it was concluded at the time that exploitation of the relatively low-grade deposits would not be economically viable using conventional techniques and that bioleaching, as an alternative method, was not yet mature for commercial use. Hence, the deposits remained unexploited until Talvivaara acquired the rights to mine the deposits and continued the geological and metallurgical work.