Godden Mackay then prepared a detailed conservation program in consultation with the Australian Heritage Commission and the Australian Antarctic Division. Between December 1997 and February 1998, Geoff Ashley, of Godden Mackay, was Conservation Team Leader of the AAP Mawson’s Huts Foundation expedition which contained 11 persons to undertake the works. In addition to Geoff Ashley and a conservation team of three builders/carpenters, an archaeologist and a photographer/artist, the party included a doctor, camp manager/cook, journalist, communications officer and expedition leader.

This expedition successfully achieved its conservation objectives, including a building and structures conservation works program (in both the Main Hut and other AAE Huts and Structures), an associated building archival recording and condition survey project and an archaeological program of Mawson’s Huts and Cape Denison as a whole.

Conservation works on the Main Hut included the following:

• re-cladding over the existing workshop roof with new Baltic pine boards;
• restoration of skylights, skylight covers, ridge capping, valley gutters and adjacent flashings;
• removal of snow and ice, as necessary, to gain access and undertake structural repairs; and
• reconstruction/restoration of the central platform structure in the living section of the Main Hut.

Conservation works on other AAE huts and the Memorial Cross included the following:

• re-cladding of the Magnetograph House roof, rehanging of its double stable door and refixing of loose tar-paper internal lining;
• excavation and restoration of original building fabric of the Absolute Magnetic Hut, buried in ice, including four structural members, loose boards and a double stable door;
• restoration of the structure of the Transit Hut and refixing of loose boards; and
• excavation of the cross arm for the Memorial Cross and its re-attachment to the post using purpose-made stainless steel brackets.

The associated conservation program included:

• preparation of measured drawings of each of the huts;
• archival photographs of the huts prior to works and photographs during and after works;
• photogrammetric recording of the Main Hut;
• building structure level surveys;
• assessment of timber moisture levels and steel corrosion,
• relocation of the 1984 Apple Hut out of the Main Hut valley;
• tidying-up of the Granholm Hut and seatainers ready for later repatriation; and
• the removal inland and detonation of AAE gelignite explosives located 100m west of the Main Hut and some 1960s emergency flares near the Magnetograph House.

The archaeological program focused on reducing the impact of the building works by recording areas prior to commencement. The work included the following:

• use of ice cores in the Main Hut to assist in micro-environment and stratigraphy assessments;
• monitoring of ice removal and recording of artefact deposits on the central platform;
• internal and external artefact surveys;
• deployment of data loggers to record temperature and relative humidity and hand-held readings;
• forensic investigation of the remains of the AAE husky dog; and
• repatriation to Australia of Webb’s Lantern and an AAE kerosene can.

Ice was removed to gain access to the Main Hut and to undertake works to stabilise the living section platform. Approximately 40 cubic metres were removed. Figure 7.14 shows the amount of ice remaining after the works were completed. Approximately 301 cubic metres remain in the Main Hut: 176 cubic metres in the verandahs (58 percent of total ice in Main Hut); 50.5 cubic metres in the living section (17 percent of total ice and 28 percent in living section space); and 74.5 cubic metres in the workshop (25 percent of total ice and 66 percent in workshop space).

The approved 1997/98 works plan called for the temporary removal of the original roof boards on the Workshop, the fixing a new layer of Baltic pine boards and the re-fixing of the original boards. However, site tests revealed the difficulty of doing this without damage to original fabric. The process would also have been very time-hungry, a critical factor given the scarcity of wind-free days. The approved work plan allowed for an alternative approach of cladding new boards over the original in situ boards, and this was undertaken.

The new boards could have been placed upside down to hide a protective honey-brown UVC finish (Intergrain) added in Hobart, but meant to be hidden under the original boards. Due to the asymmetrical manner in which the boards had been cut, this would have exposed the tongue and groove board joints in about half the time than if the boards were placed with the treated side facing upwards. A decision was made to expose the new finish and accept a short-term visual impact from the coloured boards in exchange for doubling the life of the new boards. This experience highlighted the need for careful consideration of any use of protective coatings. The results of the expedition reinforced the need for agreed alternative options to be developed as part of work plans, the difficulties associated with intervention in existing fabric, and for decisions to be based on an assessment of both shod and long term impacts.

Deployment of Monitoring Equipment

The AAP Mawson’s Huts Foundation Seminar of October 1998 strongly endorsed the need to undertake monitoring of the Main Hut. The Foundation assisted in the purchase of monitoring equipment, including temperature and relative humidity sensors and a datalogger. A private expedition to Cape Denison kindly deployed the monitors in January 1999, following cancellation of an ANARE expedition which was to deploy the monitors. The works undertaken in 1998 showed the hut to be in good condition, although an amount of snow drift had entered the Main Hut through the roof and had collected on plastic sheets left to monitor snow and meltwater ingress. The private expedition also kindly removed some equipment left unintentionally in 1998. The results of the monitoring are contained in a report by Vinod Daniel of the Australian Museum, included as Appendix C of this CMP. An analysis of these results will guide the implementation guidelines identified in this plan.