If this was anything like a typical process, drilling fluid would be pumped under pressure down the drill pipe. Not a few drops - rather hundreds (or thousands) of liters. Obviously, this is not hard-rock drilling so I'd assume the volume of drilling fluid would be reduced. It would still have to be a substantial amount, definitely more that 1.5 cubic meters.
It is not much like a typical drilling process. The article includes a pretty decent infographic abt 2/3 way down, which shows the drilling principle on the last slide. Worth a look.
So now that the drilling hole is flushed of antifreeze and its filled with prehistoric lake water... what's to stop it from freezing and closing off the hole again?
