Let’s drill a borehole!

Welcome to the second part of my blog! I write this on day #9 of my fieldwork.

Don’t fall in, I don’t want to have to pull you back out!

On the last instalment, we had moved all the gear into position to begin drilling, and had noticed what we thought was a sizable crevasse running almost directly under our equipment. Well, we thought it was sizeable, until Yoann managed to locate a larger one with his left leg! It was the first day we had decided not to wear snow shoes, and with the snow level decreasing in the brilliant sunshine, the crevasse was not far below the surface. Bad luck for Yoann, but he managed to climb out safely, and still smiling!

As it turned out, the crevasse running through the field site had sealed over-night, and so became a perfect water store. Since there are no meltwater channels currently on the glacier surface, it was necessary to dig a trench to obtain water for the drill. A pit was dug into the crevasse which held a nice amount of water and we drilled a 10m “practice borehole”. The set-up of the system took a while as it required connecting all of the hoses; fortunately this process only needs to be completed once. It was slow going as we got used to how the drill works, which certainly only seems to be when it feels like it!

Yoann relaxes on the drilling rig as the clouds creep over Kebnekaise.

The next two days produced some terrible weather, with 25m/s northerly winds in the Tarfala valley, and equally fast winds blowing down the glacier from the west. Braving the moraine to transport equipment to the glacier became a nightmare as we were nearly blown over on several occasions. We started early on day #6; lucky as we took 3 times as long to get out onto the glacier than usual. The wind had buried our equipment in snow and our crevasse water pit had drained over-night. Fortunately, the strong winds died down by around 3pm. We dug a new water pit; attempting to enlarge this pit with the hot water drill resulted in drilling into a fracture and draining all our hard work! It’s all a learning experience! We also successfully managed to drill (what we thought was) a borehole to approximately 52m deep. This was a very long day, involving us staying out on the glacier until 10pm. We were tired but relieved we had made some progress.

Come take a dip in our shallow plunge pool. Warning, may contain drill hose.

Day #7 was calm and sunny and we were relieved to see that our water pits were still present and, more importantly, still contained water! We received a couple of visits during the day by some students from a high school in Stockholm who were experiencing life at an Arctic Research Station as part of their end year projects. They were able to look at and take part in some of the work the scientists in Tarfala were completing, including our hot water drilling exercise. When we completed the borehole, we quickly realised that we must have drilled through a fracture, as the water had clearly drained away. In a way, this is beneficial, as there is no water in the borehole to freeze and close the borehole. However, it also means that we cannot use the seismic source here. We decided to attempt to drill the second hole, hoping the water in this would remain, however within 1.5m this also drained of water. As it was 4pm by this point, we decided that we would call it a day, returning to Tarfala to enjoy a more relaxed and warm evening with a barbeque!

Watch you don’t fall in, it’s a long way to the bottom!

On day #8 we were joined by the third member of our field team, my PhD supervisor, Tavi Murray. After spending the morning ringing around what felt like most of Sweden, I managed to track down our remaining field equipment coming from Malå, and organised to be flown up to the glacier later in the week (great news). On the glacier we started to drill borehole #2, 1m west of the borehole we had started the previous day; this was an attempt to produce a non-draining borehole. Unfortunately this was unsuccessful. We spent the afternoon attempting to clean the diesel heater to make it more efficient. The heater had other plans and decided that it wanted the afternoon off. We collected an inclinometer survey of the existing borehole (BH1), and found that our “80m” borehole in fact 108m deep. It also demonstrated the issues with continuing drilling a borehole a day later, the first day the borehole was straight, the second, the borehole was diverted downflow by 10m!

Today, we tried to get up onto the glacier with the addition of a Tarfala field assistant, in order to drill a second borehole, located further towards the centre line of the glacier in an attempt for it not to drain, and to collect the first real data of the field season. Regrettably, the weather today was not on our side. Rain on the exposed ice at the glacier surface, without the addition of crampons, resulted in multiple members of the field team travelling across the glacier in a seated position! Defeated, we returned to the station just in time for a cup of tea! An unsatisfying end to the day with regards to science, but fun sliding down the snow slope back to the station!

The snow thaws as the station begins a new season of scientific study

With much better weather promised for tomorrow, in addition to our remaining kit arriving by helicopter, we hope that we can get some real science done!

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