Hot Water Drilling

Expertise and capability

British Antarctic Survey leads the world in hot water drilling through ice.  We provide the hardware and expertise to access subglacial environments around the world; and the ocean cavity and seabed beneath ice shelves in the polar regions. Together with borehole sensors and cameras, water-sampling, and down-hole sediment corers we are ready to support grants, collaborations, and strategic programmes seeking subglacial access.

The hot water drills

British Antarctic Survey has developed and applied the technique of hot-water drilling to provide subglacial access for more than 30 years. This technique enables direct observations and sampling of the ocean cavity and seabed beneath floating ice shelves and sediments beneath grounded ice.  These observations are central to characterising ice-ocean and ice-bed interactions and revealing recent ice history captured in subglacial sediments.

The drilling group develop, maintain, and support a range of drills that have a fully modular design, capable of being deployed by Twin Otter, helicopter, or over-snow traverse. The current hot water drill (HWD) infrastructure for use in the Arctic and Antarctic consists of three independent drilling systems with depth capabilities of 800 m, 1000 m, and 2300 m. These systems all use petrol-fuelled generators, and water-heaters powered by aviation fuel to heat the drill water to around 90 °C. For example, the 1000 m hot water drill system uses high pressure pumps to deliver 120 litres of water per minute down the drill hose. The resultant 0.75 MW of heating power can melt a 30 cm diameter hole at up to 1.7 metres per minute. Since 2011, this drill has reliably provided 15 subglacial access holes up to 900 m deep through Larsen-C, George VI, and Filchner-Ronne ice shelves.

Subglacial access

A variety of instruments can be lowered down these subglacial access holes to capture a wide range of data.  These include:

  • Ocean profiling instruments for water mass properties
  • Water samples taken at discrete heights in the water column
  • Sediment cores from the ocean floor or beneath ground ice for ice sheet history
  • Sub-ice shelf moorings to capture long term oceanographic measurements
  • Ice column instruments for long term temperature and ice deformation measurements

In addition to the hot water drilling systems, an array of instrumentation is also maintained, including borehole sensors and cameras, water sampling instrumentation, surface sediment corers, gravity corers and winching systems.

 

 

Once a subglacial access hole is drilled, freezing will close the hole within a day or two. In order to maintain subglacial access, the hot water drill reamer is periodically used to restore the hole to its original diameter.

 


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