The sea ice on which the operation took place typically forms between April and June, and then thickens to around 2 m by early October. Water depths ranged from 122 m (CRP-1) to 295 m (CRP-3).

Operations during set-up phase

Each season in late August a group flew to Scott Base on WINFLY, and established a route on the new sea ice north to Cape Roberts. They then located the site for the rig, assembled the Cape Roberts Camp a few hundred metres north of the Cape on the sea ice. At the end of September as the ice thickened to more than 1.5 m they towed out the 55 tonnes of drilling rig, drill pipe, and ancillary buildings, and set these up at the drill site.

The drilling system used for the Cape Roberts Project was a Longyear wireline Series Q HD44 slim hole system commonly used for land-based mineral exploration. Thin kerf diamond coring bits on the end of the drill rod are rotated at high speed to drill the core, which is collected in a 3 or 6 m core barrel. The inner part of the barrel containing the core is recovered with a wire line so that the entire drill string is not removed each time core is recovered. This enables coring at rates of 30 to 40 m/day and high quality core recovery.

Operations at the drill site

The sea riser (see diagram below) was required to give lateral support to the drill rods in the water column which are rotated at 600-1200 rpm for diamond coring and to provide a return path for drilling fluid and cuttings. Modifications to the riser system were carried out after the completion of the first hole (CRP-1 in 1997) which identified some shortcomings that would become critical in the proposed deeper water sites. The modified riser system was used successfully in both following seasons.

The mud system is a very important part of the drilling operation because it provides stability in the hole; control of downhole pressure and most importantly increases core recovery and condition. The mud program used was a non toxic biodegradable low solids system mixed from sea water with potassium chloride (KCl) to increase the fluid density and natural gum polymers to increase viscosity to keep cuttings in suspension so that they can be cleared from the hole. The cuttings produced from diamond coring were mostly fine sand, silt and clay. The sand and silt were removed from the mud in a centrifuge with a processing capacity down to 5 micron size particles before it was recirculated down the hole.

Drilling statistics for the Cape Roberts holes

Operations at the Cape Roberts Camp

Cape Roberts camp is home for up to 40 personnel during the drilling phase of the operation. These include project manager, Jim Cowie, chief scientist, Peter Barrett, the drilling team led by Pat Cooper, the core processing team led by Alex Pyne, around 15 of the science team for core measurements and description, and the camp support staff.  Erecting the camp on sea ice minimised impacts on Cape Roberts, only 7 hectares in area, and provided easy access to the sea for water and waste discharge. Follow this link to see the core Cape Roberts Camp Staff throughout the project.

Life was set by the 12 hourly shift change at 0800 and 2000, which is effected by helicopter. On just a few occasions each season bad weather forced the shift change by Hagglunds tracked vehicle, the 23 km sea-ice road taking around 50 bumpy minutes to cover.

Six interconnected shipping containers connected by a cold porch walkway made up the central services part of the camp. The generator room housed two 75 kVA air cooled generators that provided the electricity requirements for the camp. One generator could also be used as a duplicate unit for either the camp or drill site if necessary. Sea water was desalinised in the plant container with a reverse osmosis system providing up to 2,000 litres of fresh water per day. The plant room also housed the waste water discharge system, fresh water filtration, heat exchangers; a JP8 fuelled boiler and hot water storage.

Three showers and hand basins were available in the ablutions container with separate laundry and 4,000 litres of fresh water storage. The kitchen container was fitted out with cooking facilities to provide meals for personnel working 12 hour shifts. The sleeping accommodation at the camp was in electrically heated and insulated 6-berth containers arranged with 3 containers each sharing a common cold porch.

The science lab, housed in 2 containers, was the area where the core was logged, described and then stored until it was transported to the Crary Lab at McMurdo Station.  

Operations of Science Team at Cape Roberts and at Crary Laboratory, McMurdo Station

The project thanks the US Office of Polar Programs for the use of Crary Engineering and Science Center, McMurdo Station, for core analysis.

The science team were staged to arrive each season when the core was expected, those with tasks at the drill site or Cape Roberts arriving first. Once coring and sampling were completed, the focus turned to the production of text and images for the Initial Report, which was largely completed each season over a period of 3 weeks following the drilling and before the science team left the ice. The Initial Reports for each season have been published around 4 months later in Terra Antartica.  Details of how this work was carried out can be found in these reports.