The hot water drillers have begun to melt the main borehole.
This hole is located alongside the well hole, and the first step is to melt down through the firn layer to approximately 100 metres, and intersect with the well cavity. The team will make several passes with the hot water drilling system, using a series of reamers to gradually widen the hole to a maximum diameter of 350 mm. Then it’s time to go all the way through the 580 metre-thick ice shelf to reach the 55 metre-thick sea water cavity.
Once the hot water drill breaks through the ice shelf the water level in the borehole will equilibrate to mean sea level. Another few days of reaming the main borehole will follow, and then the ‘open hole’ will be available for science operations. The science team will use a winch to deploy a gravity corer, borehole camera, and oceanographic equipment to measure salinity, temperature, and pressure.
