7 January 2025
Weather at 6pm: Temp −32°C; Wind 10 kn
If something is dropped down the drill hole then you need to ‘go fishing’ if you want to keep drilling.We didn’t drop anything, but it’s worth practicing what to do if we did.
A trick to fish non-magnetic objects (like a screw) from the borehole is a conical reamer. This device cuts a cone-shaped depression at the bottom of the borehole. You then drill over the cone, pray, and pull up the core – in theory with the object sitting in the depression at the top of the core. It worked beautifully and all credit to Chris Young in the Australian Antarctic Division's instrument workshop who made it.
See the nice cone in the top of the core in the picture. But I hope we don’t have to use it!
Along with the conical reamer, our plan with the drill today was to test the reamers that we will use to increase the borehole diameter in the top 120 metres of the main borehole, in order to install the borehole casing (to keep the borehole open over winter).
We noticed play in the output shaft of the drill transmission. Etienne and Derryn pulled it apart and found a stripped thread on the shaft. We have one spare output shaft, which was swapped in. You’re wise to carry spares for everything in Antarctica! The drill was then readied for reaming tomorrow.
Over at the main borehole drill shelter construction site, the snow blowing was finished and surface screeded level. Then the driller operators' cabin, and changing cabin, were craned in to position. Arches for the drill shelter were put together on the ground ready for standing up tomorrow.
It was a very cold day, down to −45 to −50°C wind chill. Lots of windmill arms going on around camp with folks trying to warm their fingers. Most people are wearing their full down freezer suits and goggles. Everyone is in good spirits despite the tough conditions and there's a sense of satisfaction around camp about our progress.
8 January 2025
Weather at 6pm: Temp −26°C; Wind 8 kn
It was a massively productive day here at MYIC-DCN.
At the main drill shelter construction site all the arch frames were stood up, and a heavy rectangular ‘pass through frame’ was installed in the roof using two Challenger tractor cranes.The pass-through frame allows tall ice drill masts to protrude through the roof of the drill shelter.
Barn doors were also built and installed in the south end. The shelter is ready for pulling over the tarp cover tomorrow. We also deepened the drill trench to two metres into the firn.
We also tested our 176 mm and 222 mm reamers that will be used to expand the width of the main borehole. We reamed to 45 metres in about two hours with the 176 mm reamer.
With the small reamer we could ream 2 to 2.5 m per run and with the larger about 1.5 m. It is good to be able to play with depths and settings like this before we move to the main borehole.
We always have the reamer spinning when it is in the borehole, even while ascending and descending. This reduces the risk of getting stuck.
Tomorrow we’ll continue reaming with the 222 mm and then switch to the 260 mm.
9 January 2025
Weather at 6pm: Temp −27°C; Wind 3kn
First up, a huge congratulations from the traverse and MYIC teams to our friends at Beyond EPICA, who announced today that they have completed drilling to bedrock at a depth of 2,800 metres. This comes after four seasons of drilling at their Little Dome C site, which is 45 kilometres from MYIC Dome C North (DCN).
Their initial analysis indicates a continuous climate record extending back 1.2 million years. This becomes the longest continuous ice core record yet recovered from Antarctica. An impressive and inspiring result that we hope to build on in the years ahead with MYIC DCN.
A major step in this direction was completed for us today with the cover going over our drill shelter. All hands from camp helped to haul over the huge cover with ropes, and secure it down. We now need to set out the core processing system inside the shelter, install flooring and deepen the drill trench. Then we can move the Eclipse drill into the drill shelter and start with pilot drilling the main borehole.
At our drill site outside the drill shelter, we continued with testing the borehole reamers. The reamers are designed to capture ice chips produced by the cutters, in a barrel that hangs below the cutters (see picture).
We always leave the reamers spinning to reduce the risk of getting stuck. However, one challenge is that a lot of the ice chips are not being captured in the barrel, instead falling to the bottom of the drill hole. Tomorrow we will try to drill over the chips to remove them. This will inform how we manage reaming and chip recovery runs for the main borehole.
Chris and Chelsea completed two six metre Kovacs cores on a transect south of camp. These will be used to look at spatial variability in chemical and isotopic markers in the snow.
We also spent some solid hours deepening our drill trench toward its final target depth of 6.2 metres. We are at about four metres now. The temperature in the trench is below -40°, but when you are down there in a freezer suit shovelling it doesn’t feel that cold.
10 January 2025
Weather at 6pm: Temp −27°C; Wind 3 kn
Another busy day at Dome C North. Some of the traverse crew worked on lining the floor with squares of plastic grid (see pic). The tent cover and ends were tightened and secured and a ‘sky light’ cut in the roof of the tent and secured to the pass-through frame. This gap will provide ventilation and cooling to the tent. We also installed the personnel access doors to the shelter.
At our shallow drill site we tried to recover chips from the bottom of the borehole but ran into some learning opportunities.
We couldn’t recover chips on the first attempt, we think due to the anti-torque catching on a reaming step and leaving the drill spinning part way down the borehole. We changed to smaller anti-torque skates and on descent think the drill head may have rested on the shoulder of a reaming step. The cable became loose and came out of the capstan wheel at the top of the drill. This kinked and shorted the cable at about 30 metres depth, and we lost power to the drill.
We stayed cool, retrieved the drill and confirmed the cable was damaged. The damaged section was cut off. Since we now needed to re-terminate the cable we decided that it was a good time to unspool the entire cable and trim it down to 250 metres, removing another small kink from a previous season of drilling that was at the other (drum) end of the cable.
In removing the drum from the winch, Etienne found an oil leak which he chased back deep into the winch. So tomorrow our drilling jobs are to replace a damaged seal in the winch, respool the shorter length of cable on to the drum, and re-terminate the cable to the drill and winch.
Meanwhile we chip away at deepening the drill trench to six metres and Chelsea and Chris finished the third six-metre Kovacs core.
11 January 2025
Weather at 6pm: Temp −27°C; Wind 9 kn
Early knock off today for pizza night after a super productive week.
What we did today:
Around the drill shelter
- Tiling of floor with plastic grid finished.
- Gantry with power winch built to help hauling out the last couple of metres of firn from the bottom of the trench.
- Snow blown around outside of shelter skirt
- Barn doors finished.
- Four of our ice core processing benches built and over next two days we’ll set up the ice core processing line.
- Power connected to the drill shelter and drill ops cabin, thanks to sparkies Ryan Kunst and Mark Cook.
Eclipse drill
- Cable respooled neatly onto drum with use of shims at cross over points and cable re-terminated at winch and drill end. Reterminating cable is a fairly bitter task in −30°C and wind, but Derryn and Etienne got it done.
- Leaking seal in winch transmission replaced.
Geophysics
- Daniel and Chelsea spent most of the day out on the quad with the ApRES survey gear and completed two more stations with polarising experiments for ice fabric and strain rate experiments.
The team is deservedly proud of all that has been achieved in the past 11 days. We now have a powered drill shelter and are excited about moving in to start pilot drilling early next week!
12 January 2025
Weather at 6pm: Temp −27°C; Wind 8 kn.
The MYIC team had a late start today after our busy week.
Today we:
• Moved the Eclipse drill into our brand spanking new drill shelter.
• Finished digging the deep trench – this bullet point should have trumpet sounds effects!
• The trench is 5.8 metres deep and 76 centimetres wide. We used the gantry power winch that we built yesterday to haul out blocks of firn from the trench in bulker bags. The blocks are cut with an electric chainsaw and popped out by shovel. The electric saws were not fazed by the -40°C temperature in the trench. We usually had two people in the trench cutting and digging, with the guide of a long spirit level to keep the sides true, and a couple of people on top, operating the winch and hauling out the snow blocks on to a plastic sled. This system worked well and it’s very satisfying to have another big job done.
• We moved four core logging benches into position and started setting up a V-channel for core processing. Some more work is needed tomorrow to level the benches.
13 January 2025
Weather at 6pm: Temp −30°C; Wind 6 kn
We spent today getting everything in place to start pilot drilling. We could have pushed it to start drilling today. But it is better to take time to make sure everything is set up and everyone is ready for our main objective to start drilling the MYIC core. We are all set for tomorrow.
Today:
- Core processing benches were levelled and aligned. An aluminium core processing V-channel was assembled on the benches and inset with polycarbonate strips to reduce temperature shock to the ice. A drop saw was set in position. All benches and the v-channel were then cleaned ready for use.
- Sample bags and vials were labelled.
- The deep trench was finished yesterday, ready for the AAD deep drill to be installed next year. As we are pilot drilling with the Eclipse this year, we boarded over part of the trench and made some modification to the trench guard rails to suit the smaller drill.
- The Eclipse drill was fixed into position to start the borehole 485 mm from the face of the trench. This needs to be precise for when we come back with the deep drill next year to continue the drilling.
- Kick boards were put in place to stop things falling into trench and a trapdoor for the borehole was made by Chippy Dave (nothing gets past!).
- A ladder was secured for access to the trench.
- Ice core boxes were moved next to the drill shelter ready to fill with core.
- Rob Teasdale dug a deep trench with the Pisten-Bulley to pre-cool our ice core transport box. The walls contain phase change material which freezes at −21°C.
- Core dogs were sharpened and core dog springs changed to the softest springs, ready for catching the softer cores near the surface.
