According to Government`s decision in principle Teollisuuden Voima Oy is obliged to make bedrock investigations for the final disposal of the spent fuel produced by its power plant in Olkiluoto. Areas in Kuhmo, Hyrynsalmi, Sievi, Konginkangas and Olkiluoto were selected for the preliminary site investigations to be carried out during years 1987-1992. In Romuvaara, Kuhmo the investigation program was started in April 1987 During years 1987-1988 a deep borehole (979 m) and 4 about 500 m deep additional boreholes were core drilled in the area. Various parameters were measured from the flushing water during the drilling. Corelogging included collecting detailed data of fractures and determining the weathering degree and petrographical properties. Rock mechanical properties, uniaxial compressive strength, Young`s modulus and Poisson`s ratio were measured from core samples.