7 July 2009

Skiway maintenance


Chain saws are essential in ice core research. Left: Celia is expanding the tunnel between the drill and the science trenches to make room for tall participants expected to arrive to camp later this week. Right: Some drillers have build up an intimate relationship to the spinner used to separate drill liquid from ice chips.

Maintaining a skiway on snow in polar regions is an art. ‘Grooming’ is the term for driving up and down the skiway in a heavy vehicle with a beam or a tiller hooked on whereby the snow surface gets flattened and compacted. The same technique as is used in the Alps to prepare skiing areas. With a typical speed of 10 km/h and the skiway being 4 kilometres long and 65 m wide it takes several days to prepare the skiway and the loading area (apron) in the beginning of the field season. Once the skiway is hardened it normally only takes 1-2 days of maintenance before a skier is expected. One of the tricks is to groom during the day when the snow is warm and let it settle during the colder night, which makes a hardened surface. After each flight mission the skiway is evaluated by the pilots. The better the skiway the heavier pay load will be approved for the next flight and the worse weather is tolerated for landing and take-off. If the skiway is in a poor state the skier may not be able to take off with high pay load and it may need to off-load some retro cargo, such as ice core boxes, in order to loose weight. With a flight-hour cost of several thousands of dollars it is essential for a project like NEEM to maintain the skiway as well as possible.

What we have done today:

  1. Drilling with the NEEM long drill: 34.24 m. Drillers depth: 976 m.
  2. Logging brittle zone ice. Final depth: 650.10 m.
  3. No ice core processing today. Brittle zone has been reached.
  4. CFA analysis: 26.40 m. Depth: 301.95 m.
  5. Grooming skyway with beam
  6. Expanding tunnel between trenches

Ad.1: Drillers Report July 6: ‘It’s another new week in the drill trench and drilling continues to go well with 37.28 m of core recovered for the day finishing at 941.76 m.’

Weather: Mostly overcast and temperatures between -4 and -7°C. Wind 10-20 knots from S. At midnight -4°C, surface definition fair, horizon good, visibility 5 miles.

FL, Anders Svensson

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