Scott Base and Mcmurdo Station

Between 12 October 2015 and 5 December 2015, Webster Drilling was tasked with undertaking a geotechnical drilling assessment at both Scott Base and McMurdo Station. This provided an opportunity to modify and test a coring system that we had previously developed and used in both the Antarctic and Arctic.

The system uses conventional down-hole coring equipment and a cold-weather-adapted Webster Drilling HPP 150 drill rig. The equipment for this project weighed a total of 4,200 kg, including spares but excluding fuel.

The main difference with this system is the flushing medium, which in this case is cold, compressed air. Air from the compressor, generally around +40°C, is diverted through a set of highly effective cooling radiators that rapidly reduce the air temperature to ambient before it enters the drill string on its way to the bit.

We have found in the past that one of our biggest problems is melting the formation, particularly where there is a high quantity of ice in the formation. This melting, caused by frictional heat at the bit, can refreeze on the bit face, halting drilling. The bit then needs to be retrieved, the ice removed, and the bit face cleared.

During the project, 154 metres of drilling was achieved across 38 drill holes.

Impregnated diamond bits were used to drill basalt and scoria, while TSP (Thermally Stable Polycrystalline) CubiPAX bits were used in fine-grained fill material.