[en] This report concerns mise-a-la-masse surveys conducted autumn 2006 at the area of the underground characterisation facility (ONKALO) and surroundings. Field surveys were made in both drillholes and on the ground surface. Suomen Malmi Oy conducted the fieldwork. Astrock Oy supervised field surveys and processed, interpreted and reported acquired data for Astrock Oy. The purpose of the study was to collect data for geological modelling with following continuity of the conducting features in bedrock from drillhole to drillhole and to ground surface. These conducting features in bedrock are often linked with lithologic characters or weakness zones. The completed survey supplements previous mise-a-la-masse measurement and on the other hand widens investigations to the newest drillholes OL-KR40-OL-KR43. A basis for the current survey was the previous mise-a-la-masse measurements and their results. Current earthings were placed in 15 electrically conducting structures in three drillholes, two at an investigation trench and one in ONKALO. Current earthings were situated in drillholes OL-KR4, OL-KR27 and OL-KR33, at OL-TK13 and at chainage 899 in ONKALO. Electrical connections were probed in nine drillholes, in four pregrouting holes and at two ground survey area. The acquired survey data were collected to xyz-coordinate oriented databases for 3D processing, interpreting and visualization of the results. At first the data were transferred to Oasis Montaj, where the potential field profiles were drawn and studied drillhole-by-drillhole current earthing at a time to determine characteristics of the electrical connections. Next probable connections between drillholes were constructed and moved to Surpac (registered trademark) Vision 3D software for visualisation. They were delivered for Posiva Oy as Surpac (registered trademark) string and DTM files. With the mise-a-la-masse data, it was possible to determine low dipping electrically conducting structures, congruent with the previous surveys. The best electrical connections from current earthings in drillholes OL-KR4 and OL-KR27 were found to drillhole OL-KR40. Drillholes OL-KR41, OL-KR42 and OL-KR43 are too remotely situated for reliable interpretations. Ground surveys were hampered strongly by electrical disturbances of the infrastructure in the Olkiluoto. Results of the all surveys are also collected in the same table, where every one of connections is classified. Interpretations are merely based on mise-a-la-masse data. (orig.)