Antarctic report 5 – Prime Movers, melt tank and cricket

Artist's impression of sled being readied for Prime Mover

This is the fifth  in our series of reports from David Goulden working for The British Antarctic Survey.

As we have not received fresh photos we have used an artists impression to illustrate the arduous work of offloading the Igaka.

We are preparing for the arrival of the supply ship Igaka. Creek 3 will be our relief area for unloading the vessels when they arrive. We have been briefed on our roles and responsibilities and taken a trip down to the sea ice to get our bearings. There are essentially 3 work stations: Sea Ice, Depot Point and Prime Mover

We will be based on the Sea Ice and be in charge of coordinating loading cargo from the ships hold onto the sledges. The Cargo hold for the Igaka is a double height hold and has a false floor that closes above the lower cargo deck and that can then be loaded with more cargo.

A team of snow cats will shuttle from the shelf ice Depot Point down a 500m ramp to us on the Sea Ice where we have a single sled. This sled will be loaded and then taken back to the shelf ice Depot Point. Once a number of sleds have been loaded a Prime Mover (Challenger snow tractor) will hitch them up and travel the 30 mins to Halley base where they will be unloaded.

Each piece of cargo has its own ID number and specific location for where to will be dropped along the depot line. This is vital as once we have off-loaded the ship this depot line will be in the region of 4km long – you can imagine how long it would take to search for a box or crate of materials!

Loading of the sleds at the Sea Ice can take up to an hour on each lift. The GRP nose cone modules are a bulky and eccentric lift and require there own modified sleds. Removing the strapping to the cargo in the hold will be a task in itself. Over 15t of timber were used in securing the loads to the marine surveyors satisfaction and this is not including the pallets that the cargo sits on.

It is critical that we keep the snow cats moving as we control the pace of the whole relief operation. A prime mover will leave on the hour with the following two leaving at 20 min intervals. This bus time table must be kept to.

The ship is currently less than 200 miles away from us but has been caught in the Stancomb Wills ice flow. This is an area of faster flowing and calving ice shelf adjacent to the Brunt ice shelf (our home). It has been stuck solid for 3 days and has been unable to break free. Ice thickness and density is measured in 10ths – the Igaka is currently stuck in 9/10ths pressure ice.

While we wait we have had other interesting work. We have been tasked with unblocking the melt tank snow chute. All water for the base is created from snow melt water. A large tank (kettle) collects the dozed snow and melts it for our use. The tank was initially buried at ground level and is a circular caisson with a long tube feeding the tank itself. The dozers daily move snow down the shaft. The tank is now over 35m below the snow level. The access ladder to it is raised every year several metres at a time.

The problem we had was that the ice shelf itself had lifted the melt tank and in the process caught the feeder chute and buckled it. We were to remove this length of damaged stainless steel pipe (500m diameter) and shorten the chute.

Suffice to say we had two turfers and a 10t jack working on the section of pipe before it decided to relinquish its grip on its neighbours. This had to be completed that evening so that the tank could be replenished and base have water!

We were given Christmas day off this week which was great. Adrian and I took the opportunity to start construction of a snow hole – we spent 4 hard hours digging the hole and it is large enough to sleep 2 of us. It is much harder than they ever show you on TV.

Spent Sunday morning running with some of my room mates. We ran a total of 15km on firm groomed ice. There is such a difference when the surface is solid and it is still not dissimilar to running in sand or on pebbles of Brighton beach.

A cricket match was organised for the afternoon and the weather was sunny enough to wear shorts. Sunday was also a friends birthday and so after the match we retired to the Ice Bar for Guinness and Whisky to celebrate.

The temperatures this week dipped to minus 15 deg in the evenings and there is hope that a change in the wind direction will aid the Igaka in its journey to us. The Shackleton is catching up and is only 400 miles away. If they both arrive at the same time plans will have to be altered!

We still sit and wait for ships – lets hope this week they arrive.

– David Goulden, Halley Research Station, Anttarctica

STOP PRESS have just heard that the twin otter has flown out to find a route through the ice for the Igaka and that they have transmitted waypoint coordinates for a course through the ice. They could be with us tomorrow with any luck. The Shackleton is currently trying to dodge the largest Iceberg in nearly ten years – it is approx 4km sq and drifting in there direction…..

This was followed by the following short Email on 30 December 2009 at  10:49:05 GMT:

gotta go – ship’s here, 10 mins to pack, talk soon

22/12 Antarctic Report 4 – quiet week at 75 degrees south
15/12 Antarctic Report 3 – Mech boys, adventuring and the flow
08/12 Antarctic Report 2 – Penguins, balloons, stuffing and apple sauce
06/12 Antarctic Report 1 – Nunatacs, Blue Ice and 4 beers on Saturday night

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