Storage of brittle ice cores – University of Copenhagen

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11 July 2009

Storage of brittle ice cores

Brittle ice cores in the core buffer

Brittle ice cores in the core buffer. The cores will be left in the core buffer over winter so they are less brittle when processed in the science trench..

The core buffer is filling up with 4m troughs with the brittle ice cores from the depth 600 m to the present depth 1055 m (loggers depths). The capacity of the core buffer has been calculated to be able to store all the brittle ice core over winter so they can be processed next year when they are less brittle to handle in the science trench. We find the cores are well preserved although they do contain some breaks.

What we have done today:
1. Drilling with the NEEM long drill: 13.97 m. Drillers depth: 1051.70 m (10th July 1037.73 m).
2. Training of Loggers; No Logging today
3. Removal of snow walls around core buffer to allow 4m troughs to be used in the full buffer.
4. No ice core processing. Brittle zone has been reached.
5. CFA analysis: 3.85 m. Depth: 331.10 m.
6. Monitoring weather all night for receiving skier. The skier arrived at 11 am local and 
  returned to Kangerlussuaq unsuccessful after many attempts to land in camp. Weather
  conditions with low clouds and ground fog was the reason for the unsuccessful mission.
7. Preparing 3 pallets with empty drums for retro load
8. Close down of generator for maintenance.
9.  Had a super Saturday night with curry prepared by Tim and Lizzie. We enjoyed the unexpected pleasure of celebrating with the old team that were not able to leave camp with the unsuccessful mission.

Ad.1: Driller’s Report July 10 and 11, 2009: “We said goodbye to several drillers and hello to one returning one.  The partial crew change has resulted in slower productivity as we prepare for the rest of the new drillers to arrive and settle into new shifts.  Drilling continues to be stable, but over the last 100 meters or so inclination has increased sharply from about 1.5 to 2.2 degrees.  To try to get a handle on the inclination as a first step the cutters were changed.  The old cutters had performed beautifully for more than 700 meters but have begun to show some wear.  Few adjustments over seven runs have been necessary to find a drilling mode that may help stabilize the inclination with a negative cutter load while at the same time not resulting in current limitation of the drill motor.  A cutting pitch of about 2 mm appears to be optimal right now.  By the last run on Saturday night it seemed we might be on the right track.  With the arrival of Coasol into camp we can begin to balance the borehole drill liquid column to offset the 23 drum Estisol excess in the hole.  Meanwhile assembly of the shallow drill is well underway.
Driller’s depth is 1051.70 meters.”

Weather and flight operations:
Just before midnight ground fog rolled in and made flight operations impossible. At 08:00 the fog lifted enough to call the mission but before the skier arrived low clouds and new banks of ground fog had arrived. Skier 96 attempted to land but after 2 hours the mission was aborted. Temperatures between -16 °C and -6 °C

FL, Anders Svensson and Dorthe Dahl-Jensen

Preparing the shallow ice core drill
The shallow ice core drill is being assembled in the garage by Trevor and Sverrir. The shallow drill will be used to drill ice cores for several programs and the shallow borehole will be used for firn-gas measurements extending the big firn-gas program done last year at NEEM.

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