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The Tasmanian Museum and Art Gallery is undertaking archaeological exploration to find the possible depth, extent and condition of underground storage vaults. These vaults were part of the 1820s Bond Store complex and figured as top security storage for early Hobart Town. To find these vaults archaeologists are digging pits in the TMAG Courtyard and outside the Watergate wall. All of this work is being done to inform the redevelopment Masterplan which will be the blueprint for the greatest cultural development in the history of Tasmania. The below image shows the vaults to the left of the courtyard gate.
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Who? Excavation will be carried out by archaeologists from Austral Archaeology Pty Ltd. They will be assisted by an excavator operator who has previous experience in working with archaeologists and an awareness of their specialised excavation requirements. An Aboriginal Heritage Consultant (AHC) has been engaged for the duration of the site-based works. The AHC will monitor the work and if any Aboriginal sites or artefacts are discovered they will liaise with TMAG, the Aboriginal Heritage Office in the Department of Parks, Heritage and the Arts, and the Tasmanian Aboriginal Land and Sea Council (TALSC) as required. TMAG has also appointed an engineer to manage and monitor the structural integrity of the historic ‘water gate’ wall during the test excavation. The wall support will be installed to the engineers design under the supervision of the archaeologists. In the event that any aspect of the wall appears unstable during the works, the archaeological consultants will immediately cease works and notify TMAG and the consultant engineer for advice. This work will be undertaken in accordance with approvals received from Heritage Tasmania and the Sullivans Cove Waterfront Authority. Where?
 How? A small tracked excavator of approximately 5 tonnes with a smooth-edged trimming bucket approximately 1000mm wide will be used to remove the surface material and then excavate trenches or pits. As works in Area 2 will require excavation right beside the main courtyard wall, it will be necessary to have a machine with an offset boom. Excavation will be undertaken via a series of shallow scrapes so that the exposed surface in the pit or trench is sequentially reduced in a controlled manner. Where a feature or anomaly is noted it will be investigated by hand excavation. Where space is constrained or excavation is required around in situ features a smaller mud bucket (300–450mm) will be used. Small hand tools such as picks, shovels, pointing trowels, brushes and pans will be used in manual excavation either for cleaning up excavated areas or revealing exposed features or deposits. The maximum depth of excavation is likely to be approximately 3 metres. A 5 tonne machine has sufficient boom length to excavate to this depth. OH&S requirements dictate that pits or trenches deeper than 1.5m require either shoring or opening out and benching. Excavation within a shored trench is problematic, especially where the trenches are not very wide. For that reason it is proposed to bench the trenches if depths greater than 1.5m are required to be excavated. This may influence the extent to which the site is investigated. Where deposits or contexts are noted, basic principles of stratigraphical excavation and recording will be followed, ie: removal of deposits and features in strict reverse order of deposition. Recording and documentation of archaeological contexts revealed will conform to standard archaeological methods. The archaeological works will be recorded by way of measured drawings, levels, photographs and written descriptions. Provenance data and fabric descriptions will be recorded on numbered context recording sheets and the vertical and horizontal positions of all significant deposits and features will be recorded with reference to a permanent site datum. This survey information will be transferred to scaled site plans showing the spatial relationships between features revealed during the course of the investigation. Documentary records of the excavation will be supplemented by the preparation of Context Schedules and a Harris Matrix for the excavation area (if applicable). All significant elements will be photographed with a scale bar. Digital media will be used for photographic recording. Once excavations are concluded, the site shall be left in a safe and secure condition for a display period. At the conclusion of the display period archaeologists will be authorised by TMAG to arrange backfilling and reinstatement of the site. Trenches will be lined with geofabric and backfilled with the previously stockpiled fill. Challenges The archaeological signature of the vaults may not be simple to interpret as there are a number of possibilities as to what may have occurred. The vaults may have been totally removed or remain either partially or wholly intact. If they have been damaged or partially demolished, the “edge and top of the presumed vaults” may not exist, but the rubble and debris from their destruction may still be in situ in the upper deposits. This rubble itself may provide significant information about the vaults and could warrant investigation. Likewise this rubble may be concealing deeper structural evidence which might be intact. Such evidence is difficult to interpret in a sampling excavation. It must be understood that the absence of evidence in one place will not actually prove that partial remains of the vaults do not exist. Therefore discretion will be used as to where test pits in Area 1 can be located. There may be evidence of other later buildings or structures in the courtyard that post-date the 1820s vaults (and which were built above them). These may have left their own demolition layer that would be easy to confuse with evidence of demolition of the vaults. It is therefore important to make allowance in the investigation for recording of any such evidence as this may potentially contain information on the evolution and use of the site over time. Depending on the nature of the discovery and its significance, it may be preferable/necessary to leave such remains in situ. This makes deeper excavation in the same location to find the vaults problematic. A method which allows for a degree of flexibility on determining trench locations – taking into account OH&S requirements - within the fenced confines of Areas 1 & 2 is therefore required. In September 2007 test pit excavations were carried out as a part of geotechnical and site contamination investigations for the future TMAG redevelopment project. As a result of these initial excavations additional test pit investigations were recommended to supply further data considered essential to providing guidance in the current masterplanning phase and to the future concept planning and design stages of the TMAG redevelopment.
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