Recovering the AWI drill
Troubleshouting the CReSIS Meridian UAV.
Waking up the first thought went to the AWI drill – was it still stuck or had the tensioned cable been able to free the drill?
The drill was still stuck and we decided to warm 100l of glycol and pour it down after lunch. After 50 l had been poured down the cable tension reduced significantly indicating the drill was coming loose.
Sverrir could feel that the hammer in the drill was loose and after a few
strong pulls the drill came free. Big relief!
What we have done today:
1. Packing the water vapor equipment
2. Japanese aerosol station monitoring
3. Recovering the AWI drill stuck at 50 m depth
4. Troubleshouting the Meridian
5. Cutting stable water isotope samples and measuring DEP and density of
the Ice2Sea ice core
6. Measuring DEP and density of the 50m AWI test ice core
7. Preparing the movement of the Dome back to the original position to
take place on Saturday
8. Moving the GEUS seismic solar panels up.
An evaluation of the event points towards three factors that are
weak points and together could cause the drill to get stuck: 1) The
grooves in the outer core barrel are manufactured the wrong way preventing
proper ice chips transportation. Each run ends with packing of ice chips
at the drill head. 2) The core catchers do not tip enough and the strength
of the springs probably too high. It is observed that very few core breaks
are at the core catcher positions. 3) The Danish intermediate winch does
not allow sufficient and fast pull at the breaks. Heating the winch helps
so it might be a problem with gear oil or ice in the winch.
Weather: Blue sky, temp. -18°C to -8°C, wind 5 to 12 knots from S
FL, Dorthe Dahl-Jensen
Martin and Phillip with the ‘rescued’ AWI drill. The blue glycol has coloured the ice core blue.
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