Electrothermal Drill

The Electrothermal Drill (aka Thermal Drill) melts an annulus around the ice cores it collects. It can be substituted for the 4-Inch Drill sonde, using the same winch system, for use in ice warmer than about minus 10° C. The drill collects a 86 mm (3.4-inch) core and has been used to drill to nearly 300 meters. For depths shallower than 30 m, a simpler tripod assembly for operation of the drill has been used with good success. The sonde is particularly useful in ice close to the pressure melting point, where electromechanical drills are at risk of getting stuck from melting and refreezing of the surrounding ice. The Thermal Drill has performed well in Alaska, British Columbia, and in southeastern Greenland. Most recently, in 2019, three IDP personnel traveled to Alaska in conjunction with the Juneau Icefield Research Program (JIRP) to perform drill testing. IDP performed some additional testing and operator training on frozen Lake Waubesa in Madison, WI in January 2022.

IDP has one Thermal Drill ready for issue. At the request of the science community, IDP pursued upgrades in PY 2018 to allow for coring to 300 m. New heat rings, a new 300 m water-shedding cable, a magnetic tool to aid in core removal and a prototype ethanol delivery mechanism were implemented. Testing of the upgrades was conducted in Alaska in July 2019 with the Juneau Icefield Research Program (JIRP). In 2021, a new sediment collector vacuum was designed, fabricated and tested, to remove any debris from the borehole than might impede melting and forward progress. A new core processing tray was also developed, and a lightweight configuration of components has been arranged for transport by mule and porter. A second sonde may be built up in 2023 to meet science community demand.