Field and CPL Updates

2012-2013 Antarctica

December 10, 2012
Update provided by Ken Taylor
project update image
Aerial view of the arch. Tent city is in the upper-right of the photo. Photo courtesy of POLENET.

Great news this week. All the drilling and science staff made it to WAIS Divide and many preparations for drilling were completed. The crew has started using the replicate drilling equipment down hole, which is about 10 days sooner than we were expecting. This early start occurred because of good weather when we needed it to get people and equipment in, and the great support we are getting from the camp staff. Don't get the idea that the weather has always been good, there have been many significant storms, but thanks to good support from the camp the storms did not cause much delay.

The other great news is that the drill crew has successfully started a deviation. This process involves dragging a sharp round cutter up the side of the borehole to shave ice off the high side of the inclined hole. The process is called broaching, a term that comes from machining materials. They had some problems with the broaching tool digging into the borehole when it was being pulled up to the surface at high speeds. They made a clever and effective fix using string, and are now able to pull the broaching tool up at 2 m/s, which is an impressive speed when you see the cable zipping by and the winch spinning. The ability to pull the drill up quickly is important because it saves a lot of time.

The broaching process is working at 3,000 m. Tests with the drill and camera indicate they are cutting into the high side of the hole, which is required so borehole logging tools can pass by the deviation. They are not yet a third of the hole diameter out of the main hole, which is when they will lower a test logging tool to confirm that logging tools can pass the deviation. This test will be repeated when the deviation is 2/3 and fully complete.