Little Dome C - Beyond EPICA Oldest Ice Drilling Site (75.29917 °S, 122.44516 °E) – Season 2022/23 (copy 1)

Situation Report #19bis, Wednesday 21 December 2022

Personnel @LDC: Saverio Panichi (ENEA, Camp Leader), Frank Wilhelms (AWI, Chief Driller), Robert Mulvaney (BAS, Chief Scientist), Giuditta Celli (UNIVE, ISP), Romily Harris Stuart (LSCE), Matthias Hüther (AWI), Gunther Lawer (AWI), Johannes Lemburg (AWI), Martin Leonhardt (AWI), Michele Scalet (ENEA), Julian Westhoff (NBI), Andrea de Vito (ENEA)

Personnel @DC: Markus Grimmer (UNIBE), Florian Krauß (UNIBE)

Weather at LDC 5 pm: sunny, 5 knots

Meteo at DC 5 pm: T = −36°C, Wind = SW, 5 knots, Wind Chill T = −48°C

Late the previous evening, the Danish barrels, hollow shaft and fluid pump had been replaced by the AWI components, after some modifications to the outer barrel and fluid pump to reduce the friction. We also got a complete set of new cutters on the drill head - a change from the ‘stepped cutters’ we had been using over the previous few days. Unfortunately, a mis-alignment of the fluid pump in the outer barrel rifling damaged the plastic locator ring (the orange section in yesterday’s picture), so we quickly changed to a spare hollow shaft with a ‘booster pump’ (short Archimedes spiral). We can print new plastic components using a 3-D printer located in a warm cabin in the back corner of the drilling tent, so the damage was temporary.

Unfortunately, the booster pump failed to collect the full production of chips produced by the drill head, which for ice core drilling is a dangerous situation because a build-up of chips in the borehole could trap the drill and prevent recovery. Thus, we had a series of short cores, and few chips, until we were able to again to switch back to the fluid pump. Runs from this point on gradually increased in length as the chips lost in earlier runs were recovered from the hole.

End of day statistics:

Individual runs of the drill were recorded as: 1.07, 0.00, 1.60, 0.27, 1.30, 1.73, 1.93, 2.34, 2.20, 2.41, 2.41 m

  • Drillers’ depth: 233.43 m; daily total 17.54 m
  • Loggers’ depth: 238.91 m; daily total 17.68 m
  • Processors’ depth: 112.0 m; daily total 11.0 m (planned maintenance at Concordia Station meant a power-down in the Processors cold workshop, and reduced their ability to measure and cut the cores today)

Rob Mulvaney & Frank Wilhelms - LDC, 23.12.2022

Situation Report #19, 21 December 2022

Personnel @LDC: Romain Duphil (IGE), Romilly Harris-Stuart (LSCE), Gunther Lawer (AWI), Matthias Hüther (AWI), Julien Westhof (UCPH), Martin Leonhardt (AWI), Frank Wilhelms (AWI), Giuditta Celli (UNIVE, ISP), Johannes Lemburg (AWI), Rob Mulvaney (BAS), Saverio Panichi (ENEA), Michele Scalet (ENEA), Andrea Devito (ENEA)

Personnel @DC: Markus Grimmer (UNIBE), Florian Krauß (UNIBE)

Weather at LDC 5 pm: sunny

Meteo at DC 5 pm: T = −°C, Wind = - knt, Wind Chill T = − °C

After a couple of days of SITREP sent directly from the field we are unfortunately back to old style ones, and with some delay, sorry for this, but this is Antarctica. We are indeed sending telegraphic WhatsApp to Carlo, who translates them into a better shape.

Pictures are a bit difficult to be sent. The good news is that drilling is now progressing well and we are now working well in shifts with quite good production.

What we did today:

- undertook 11 runs: 1st run with booster shaft as 3D printed torque piece of pump was damaged 1.07 m; 2nd run with the pump had problem while idlinig; 3rd run with opened screens at lower end of the outerbarrel and switched to staggared cutters, terminated after 1.6 m due to high power consumption; 4th run0.23 m terminated due to high power consumption; 5th run stopped at 1.3 m due to high powerconsumption; 6th run with hollow shaft with inner screen stopped at 1.73 m due to high powerconsumption; 7th run 1.89 m stopped to high power consumption; 8th run 2.43 m stopped due to highpower consumption; 9th run 2.17 m stopped due to high power consumption; 10th run 2.41 m stoppeddue to high power consumption; 11th run 2.41 m stopped due to high power consumption

- cut triangular openings in lower end of core barrel

- repaired pump torque sleeve

- mounted new pump on shaft

- we are defining high power consumption as above 700-800 W on surface, which is about 450-550 W to the drill; want to get a feeling what is going on and not exceed the power of the EGRIP electronics

- core processing at DC

  • Drillers depth: 233.43 m
  • DeltaD: 17.54 m
  • Logger depth: 238.91 m
  • DeltaD: 17.68 m
  • Processors depth: 112 m
  • DeltaD: 11 m

Frank Wilhelms & Rob Mulvaney - LDC, 21.12.2022