[en] Posiva Oy submitted an application for the Decision in Principle to the Finnish Government in May 1999. A positive decision was made at the end of 2000 by the Government. The Finnish Parliament ratified the Decision in Principle on the final disposal facility for spent nuclear fuel at Olkiluoto, Eurajoki in May 2001. The decision makes it possible for Posiva to focus the confirming bedrock investigations at Olkiluoto, where in the next few years an underground rock characterisation facility, ONKALO, will be constructed. As a part of the investigations Suomen Malmi Oy (Smoy) core drilled 100.07 m deep borehole with a diameter of 75.7 mm at Olkiluoto in April 2005. This borehole was aimed to get additional information of the quality of bedrock and the anomalous part of the bedrock and quality and the location of the fractured zones R19A and R19B. The identification number of the borehole is OL-KR34. A set of monitoring measurements and samplings from the drilling and returning water was carried out during the drilling. Both the volume and the electric conductivity of the drilling water and the returning water were recorded. The drill rig was computer controlled and during drilling the computer recorded information about drilling parameters. The objective of all measurements was to obtain more information about bedrock and groundwater properties. Sodium fluorescein was used as a label agent in the drilling water. The volume of the used drilling water was about 37m³ and the measured volume of the returning water was about 18m³ in borehole OL-KR34. The deviation of the borehole was measured with the deviation measuring instruments EMS and Maxibor. The results of the Maxibor measurements indicate that borehole OLKR34 deviates 0.84 m right and 0.15 m up at the borehole depth of 99 m. Uniaxial compressive strength, Young's Modulus and Poisson' s ratio were measured from the core samples. The average uniaxial compressive strength is about 142 MPa, the average Young's modulus is 42 GPa and the average Poisson's ratio is 0.20. The main rock type is migmatitic mica gneiss. Filled fractures are most common type of fractures. The average fracture frequency is 3.7 pes/m. The average RQD value is 91.6 %. In borehole OL-KR34 five fractured zones were penetrated. (orig.)