16 July 2010

Approaching bedrock

  With the drilling rapidly approaching bedrock (and a stuck drill last
  Sunday) the information screen in main dome is watched with great

Today the snow storm calmed down and we got warm overcast weather. On the surface some of the snow that has piled up around the buildings was removed and preparation of the skiway was initiated for the flights planned for next week.

The drilling is still progressing very well. So well that the base of the ice is likely to be reached within 50 m. Therefore, the drilling was stopped in the late afternoon and a seismic logger (a sonar or a ‘pinger’) was lowered into the borehole for precise determination of the bedrock depth. The sonar emits an acoustic signal that is reflected by the borehole bottom and by the bedrock/base of the ice. From the travel time in the drill liquid and in the ice, the remaining thickness of the ice can be obtained. By midnight the logger was at the bottom of the borehole, but there were no confirmative conclusions about the ice thickness.

Drilling: 18.21 m, drillers depth: 2480.50 m
Logging: 18.10 m, loggers depth: 2496.33 m
Processing: bag 4314-4366 (29.15 m) 2401.30 m
CFA: bag 3942-3981 (22.00 m), CFA depth 2189.55 m

What we have done today:
1. Drilling and core logging ice.
2. Processed deep ice.
3. CFA measurements.
4. Sonar logging of borehole.
5. Removing drift snow from around buildings.
6. Starting to groom skiway.

Weather: Today the wind dropped to a level of 8-10 knots from S. The sun could be seen occasionally but it has mostly been overcast. Temperatures between -5°C  and -8°C .

FL’s Dorthe Dahl-Jensen and Anders Svensson


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