Drilling, and wells

Down here, we get our water from melted ice using a neat thing called a “rodwell”, then when the well is used up we fill it back up with waste water. One of the projects going on this summer at Pole involves drilling a new hole into an old rodwell bulb.

The “rod” in rodwell is short for Rodriguez – an army engineer named Raul Rodriguez developed this type of well for use in Greenland in the early 60s. Essentially, a rodwell is made by melting a hole into ice, then circulating the liquid water in the bottom of the hole through a heater to melt out a bulb of water. Once the bulb of liquid water gets big enough, a fraction of it can be taken off as liquid water and replaced with air. The bulb of liquid water tends to move down, eventually creating a cavity that’s roughly the shape of an upside-down light bulb.

Down here, we predominately use waste heat from the electrical generators to heat the water in the well through a glycol-to-water heat exchanger. To given an idea of the scale – the wells here end up being about 30 meters in diameter, and a couple hundred meters tall – many millions of gallons of volume.

Drilling holes in snow or ice is typically done by using copious amounts of heat, but the subject is a lot deeper (har har har) than it might seem at first. There are a few substantially different approaches depending on how big of a hole is needed, what type of snow or ice is being drilled through, and what energy sources are available.

The drill we’re using burns jet fuel – which we run the whole station on – and circulates hot glycol through a conical coil of copper pipe. As the snow and ice around the coil melts, the coil is slowly lowered down at a rate of roughly 5 minutes per foot. This particular system was designed for ARA, which is another neutrino detector project down here, and it reuses some parts from the (much larger) drill rig that was used to build IceCube.

My part of the drilling project was pretty minor – I just assembled a cementboard cover over the heaters on the drill rig, but it was fun to get involved in a physical project for a day.

The business end of the ARA drill rig: the carrot

The business end of the ARA drill rig: the carrot

Steam and exhaust off the drill rig

Steam and exhaust off the drill rig

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About ianrrees

Nerdy guy.
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