Last night the drill bit was changed after 87.5 m and core drilling continued this morning. Good progress during the day, 75 - 80 min per core run and we passed 1250 m driller's depth. More micro-karst - and the microbiologists are happy. We began with swap sampling on the surfaces and cavities, and simultaneous sampling of drilling mud in sterile sample vessels. However, to correlate the two is not so easy: we don't know in advance at what driller's depth we can do swap sampling, the lag time in the mud circulation (the time it takes to pump the drilling mud from the drill bit to the surface) is now about 35 minutes, and there's no circulation during core retrieval. But we do our best ... it's part of "the thrill to drill"!