9. Field report

Map of the outer line. Green lenses show the planned shots. Here 18 April we have detonated shot OS5 and two shots near position OS9 and OS10 and we still need to load OS8 and OS11. The green squares with an aircraft symbol – Cache IS and Cache OS show the southern cache, we used during the operations along the inner line and the northern cache, we have used during the present operations respectively. The white square with a cross is the manned ice camp, which is also used as a cache for fuel and explosives. All the small red dots along the lines are positions where we shall deploy receivers on the ice. Here 18 April we have deployed 110.

Tired ice people on the way back home to Alert in the Twin Otter. There was no serving on board the flight. Front row – left to right – John Boserup, Ron Verrall and Bill Denomme. Second row – Ruth Jackson, Søren Bredvig Nielsen (he of the one eye), and Peer Jørgensen. Behind Ruth is Thomas Funck. The rest are pretty much hidden.

The airport at ice camp. It is here Jørgen, Mike and Greg provide services to the aircraft. There is no Taxfree in the airport.

Alert, 18 April, 2006

Received from Ron Verral and Trine Dahl-Jensen

Edited by Henrik Højmark Thomsen, GEUS

First shots on the outer line – despite the weather.

18 April, 2006

Weather in Alert: -31, light wind, sunny

Fine weather in Alert, but the weather along the outer line is not smiling on us. We had planned to load the last four shots in the northern end of the outer line and deploy the 80 receivers we did not manage to enstall earlier – and then start blasting. In the morning the satellite pictures showed low clouds and fog over the line with possibility of improvement, so we decided to postpone the departure.

Part of our problem is that the weather has to be reasonably good over a very large area. The distance from Alert to the north end of the shot line is about 240 nautical miles, or nearly 450 km. In order to get helicopters out that far, the weather has to be flyable the whole way. An additional concern is that of fuel. The helicopters can not carry enough fuel to get out to the ice camp and back. This means that at some point en route to the ice camp they pass the point of no-return. If they run into bad fog past that point they are in trouble. Consequently, they need to be quite cautious.

In order to mitigate this slightly, we now plan to leave the helicopters out at the ice camp in the care of one pilot and one engineer, and we will fly two pilots and the worker-bees back and forth in the Twin Otter. A fixed-wing aircraft like the Twin Otter is not quite so bothered by bad weather as the helicopter. Moreover, it has a much longer range, so that it can quite happily return to Alert if it runs into bad weather.

Another of our concerns is the 70 receivers that were set out on the ice on 15 April. Their battery life is finite; moreover, the batteries become very sluggish below about -20 degrees. We know from tests performed in Ottawa that the recording boxes will work happily for about five days at a temperature of minus forty. Since the temperature here has been warmer than that, they should last a few days more than five. Exactly how many more is a subject of debate. If they are left out too long, they won’t work, and they won’t provide us with any data. On the other hand, collecting them off the ice, bringing them in, warming them up, giving them new batteries and setting them out again is very time consuming. And all that time the weather may well be uncooperative and the ice may be carrying the explosives who-knows-where.

We started out from Alert 12:30, as the weather at that time had improved. All three helicopter left for the ice camp. The trip out there was reasonably uneventful, although we did have to detour about 10 miles to the east in order to skirt around a big fog bank. After refuelling at the camp, we headed north to install explosives at shot-location OS8, which was about 30 miles farther north. We were not out very far before the weather started to turn nasty. The cloud ceiling got lower and lower, the visibility decreased to about 1 mile, and the contrast deteriorated to the point that we could hardly tell what kind of ice we were looking at. The lead pilot, Collin, made the decision to turn back to the ice camp.

When we got back to the camp, there was a new plan afoot. We decided to use the Twin Otter for the shot loading operation. Meanwhile, the three helicopters would set out as many receivers as the weather would allow. After loading and deployment of receivers we would start blasting just to get some data in the can. The Twin Otter can cope with bad weather a little better than the helicopters can, but it is not able to land everywhere. We had to fine suitable landing strips close to the planned shot locations.

The Twin Otter flew to the northerly fuel cache (Cache OS) where there was a landing strip marked with two lines of snow-filled garbage bags. This site was close to the proposed shot site OS9, and so it was deemed good enough to become shot site OS9. Holes were drilled and explosives were loaded. Another 20 boxes of explosives were loaded aboard the Twin Otter, and we took off for a more northerly location. The visibility and definition improved, and the pilot, Jim Haffey, found us another nice location close to the proposed site OS10. We drilled it and mounted the explosives. By this time the helicopters had deployed another 40 receivers on the ice, before they were forced back to the ice camp by the weather. Short after we got permission over the radio to shoot, and at 21:00 we blasted OS10. The Twin Otter then went back to the northerly fuel cache to detonate the shot OS9 we just had installed just an hour before. Meanwhile one of the helicopters had succeeded to reach shot location OS5, where they detonated the shot. The helicopter team attempted to go further north to shot site O6 to detonate, but they were forced back to the ice camp again by the weather.

After the blasting the Twin Otter returned to the ice camp, where all three helicopters were on ground. The weather at the camp was so bad, that it could hardly land. But it finally succeeded landing. We left all three helicopters out at the camp and a bunch of tired ice people boarded the Twin Otter, which took off to Alert. Here it landed at 00:40. It had been a long afternoon. There are now six shots on the ice, that are loaded but not exploded and two locations that have to be loaded and detonated. We hope for good weather to these detonations. Then, all the receivers must be picked up to get the data. They hopefully already now contain good data from today´s three detonated shots. But with just a little luck with the weather, we should be able to get a lot more data, if we succeed to detonate the last eight shots, and the receivers not are running out of battery.

The ice camp is very important for our operations. The three people living out there are Jørgen Skafte, the ice camp manager, Mike Gorveatt and Greg Middleton. They are there to provide weather information and to provide services to the aircraft. This includes helping to look after the helicopters and crew when they become stationed there. Mike and Greg are also quite busy running the “drift seismic station” installed at the camp. This station is sending out sound waves in the water from a couple of airguns, which are mounted in the ocean below the sea ice. The sound waves move down through the water to the bottom of the ocean, where they are reflected from the geological layers below the sea floor. Theses reflected signals are recorded by hydrophones (a kind of microphone), which also are mounted in the ocean below the station. When the station drifts with the ice, we will continuously get data about the geology below the sea floor. However we do not have any control over, how the station is drifting. It is decided by Mother Nature, but we will get data along the random route the station is drifting. The station has collected data, since 8 April with the exception of a few short periods. We have enclosed a map showing the track over which we now have data. The station runs 24 hours per day, and Mike and Greg work twelve-hour shifts, noon to midnight and midnight to noon. We understand that they hardly ever see each other. A few days ago, Mike came in to Alert for a shower and a break, and John Shimeld took his place out at the camp. Mike was only at Alert for a couple of days, and now he is back at it.

Ice camp manager Jørgen Skafte is smiling just as he learned that the Twin Otter was returning to camp and he did not have to provide accomodation for nine people who could not get home to Alert.

Jørgen Skafte deploying a receiver on the ice. First he had dug a hole in the snow to install the instrument on solid ice. And now he is filling a garbage bag with snow, to be used as a position marker.

Helicopter pilot Bill Denomme waiting for better weather. You can tell that he is experienced in the business of waiting.

Greg Middelton looking after the drift seismic station. Greg is looking forward to a shower.

Mike Gorveatt looking after the drift seismic station. Mike smiles happily after a shower and a break in Alert.

Map showing the track over which we now have data from the drift seismic station. The operators have no control over the track; they go where the ice takes them.

© Kontinentalsokkelprojektet - a76@a76.dk Frontier Theme