On-site

Conservation begins on the sea floor with the pre-disturbance survey which evaluates the chemical and physical nature of the site. Pre-disturbance surveys enable us to develop a clearer picture of the site and gain an understanding of what material types are likely to be present and approximately what their condition upon excavation will be. Pre-disturbance surveys form the baseline study for the site and enable the development of a site conservation plan and on-site conservation requirements to be defined.

Information collected during pre-disturbance surveys can also assist in selecting what objects are most feasible to recover, particularly in the case of cast iron objects such as cannons or stoves. Pre-disturbance survey work incorporates sampling and monitoring: in particular taking corrosion potential measurements, which give a good indication of the thermodynamic nature of an immersed metallic object and an indication of the extent and rate of deterioration of that object. Objects that are more stable and less advanced in their state of corrosion can preferentially be selected for recovery and conservation.

Interventive conservation can in some cases be initiated on site. Sacrificial anodes have been connected to several anchors on the Pandora site to facilitate their stabilisation. Since a significant amount of desalination can be carried out in the marine environment by using sacrificial anodes, the length of time required back at the laboratory to conserve an object is dramatically reduced.

Once the excavation process is underway, Conservation's activities expand and generally focus on preventive conservation rather than the interventive treatment of objects whilst at sea. The experienced archaeologists working on the Pandora site know how to safely handle and pack recovered artefacts to effectively transport the objects from the sea bed to the deck of the work vessel. Once the artefact is topside it is quickly put through initial registration; photographed and sketched with site specific information recorded. During this process the object is kept wet to minimise deterioration associated with rapid and uncontrolled drying. The object and its associated information are then transferred to the conservation area where its material type is initially identified and the object is stabilised and packed for the return voyage home. The packing of the artefact is to protect the object from uncontrolled drying, oxidation, shock and vibration that can readily occur during the voyage back to Townsville.

Why do we stabilise the objects? Generally artefacts recovered at some depth within the sediment from the Pandora site have formed an equilibrium with the environment and are no longer rapidly deteriorating. By uncovering these artefacts the archaeologist inevitably exposes the object to environmental factors that can accelerate the process of deterioration. The on-site conservator's role is to buffer the artefact's transitional shock caused by excavation and this assists the later conservation treatment to be successful.