2 June 2011

Processing brittle ice is finished

The Twin Otter with the PARCA team just before they left camp. Good bye and see you again next year.

The drillers were eagerly going to work this morning, hoping that their new winch contraption would live up to expectations, and the rebuilt winch worked really well. Unfortunately, the old motor still sitting inside the winch and acting as drive shaft only, decided to continue to play tricks on them. Although it was broken, it was not so completely, so it began to do what many motors do when they are forced to rotate, to act as a generator. As it was disconnected, because of broken brushes, the electricity generated could not go anywhere, so instead it got really hot. Out of fear for the transmission and the bearings, and because of the green smoke emanating from the winch, they decided to remove the cause. They pulled the 500 m cable out on the snow a third time, opened the winch, took the old motor out and machined the coils off the drive shaft. Then they reassembled the system, wound back the cable on the winch, and are now ready for drilling again tomorrow.

In the science trench there was cause for celebration. At Noon today the last section of brittle ice was processed. NEEM has completed the processing of 2537 m ice core. The CFA people are behind due to a slower system, but they are making really good progress too.

Also today, we said good bye to the PARCA team and the pilots as they left camp at Noon and flew towards the East. They got most of their job done, and they wanted to leave camp before the forecasted high winds reach NEEM.

What we have done today:
1.  Drilling again. 4 x1.5 m beautiful cores. Depth: 154.5 m.
2.  Processing NEEM deep core brittle zone now complete. Bags 2094-2099 (1151.15m – 1154.45m).
3.  CFA measurements.  Measured 26.4 m. Depth 2354.55m
4.  Performing logging experiments in the deep hole.
5.  Said good bye to the U.S. PARCA team on the Twin Otter. They left for East Greenland today.

Drillers report: We made 4 beautiful runs today, each 1.5 m. The AC motor that has been mounted on the tower comes with an electronic frequency inverter which allows for full torque independent of RPM and very slow cable feed during drilling. This allowed for easy drilling and very controlled easy core breaks. The cores came up with no damage from the core catchers. We were delayed somewhat, because we had to remove the coils from the old motor drive shaft to avoid losing energy and overheating of the winch. Drilling will continue tomorrow morning.
Drillers rules for the past week:
1.  Check stuff
2.  Take stuff apart
3.  Put stuff together

Weather: Overcast in the morning, later Clear. Temp. - 17 °C to - 22 °C, 17 knots from SSW. Visibility 1-3 km due to haze.

FL, J.P. Steffensen

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