1994:129 - ROSS ISLAND, Kerry

The 1994 season at Ross Island began with a five week period of survey and excavation in May-early June, funded and staffed by volunteers from the American organisation, Earthwatch. The main excavation, funded by the Royal Irish Academy/Office of Public Works, was carried out over 11 weeks from June 27 to September 9. In total, some 16 weeks of survey and excavation were carried out in 1994, focusing chiefly on the continuing investigation of the Beaker work camp associated with this early copper mine.

The survey programme at Ross Island continued in 1994 with further detailed instrument survey of this mine complex. This work is being carried out to produce a detailed survey record of the mine features and a topographic base-map for geological survey. Further geophysical survey was also carried out in 1994, including magnetic susceptibility survey within the Beaker site and geological geophysics investigating the ore body itself. Detailed bedrock mapping was carried out at the site in August. The results of these geophysical surveys and the bedrock mapping will be used to plan a programme of rock drilling to be carried out in January 1995.

The first phase of archaeological excavation in 1994 saw the investigation of a 72m sq cutting (Area 12) in the western part of the Beaker work camp. This work investigated a thin spread of crushed rock sediment on eroding limestone karst. Some 200 stone hammer fragments were recovered, together with a number of anvil blocks. These suggest that this part of the escarpment was used for open-air hand-sorting and crushing of copper ore. The discovery of two fragments of copper smelting slag also points to metallurgical activity in this general area.

The summer excavation period saw the continuing investigation of Areas 5/6 and 9 on the eastern side of the Beaker work camp escarpment. Excavation of a small sub-circular hut foundation associated with early Beaker pottery in Area 5/6 was completed. A larger, possibly rectangular, house structure was also investigated in Area 9, again associated with Beaker pottery. In total, three definite Beaker hut foundations have now been identified in Areas 5/6 and 9, in addition to a structure of possible Late Mesolithic date found in Area 8 to the north. The Beaker structures are associated with a small quantity of animal bone, while artefact finds in 1994 included some sherds of early Beaker pottery and a small quantity of struck flint.

Associated with these structures in Area 9 are two pit features, previously identified in 1993. These pits (Contexts 500 and 524) appear to have functioned as metallurgical furnaces and are associated with copper-rich residues and ore, and a few fragments of smelting slag. Radiocarbon dates for these two features place them securely with the early Beaker phase of mining at this site. Investigation of these pits continued in 1994 when a 60m sq cutting (Area 13) was opened on the south side of Area 9, to investigate the full extent of the larger pit (Context 500) and the surrounding work surface. Excavation here revealed at least two further pit features and indications of a possible hut structure, again associated with early Beaker pottery.

Much of the summer excavation focused on an investigation of the larger metallurgical pit (Context 500) and the surrounding work surface. Detailed contextual excavation revealed a complex sedimentology within this pit, while several deposits connected to its use as a furnace were also identified in the immediate vicinity. Sediment samples and copper ore/metallurgical residues from this feature and the adjacent Context 524 pit were brought over to the University of Bradford for analysis. The importance of this season lies mainly in the detailed investigation of what may prove to be the first prehistoric copper smelting furnaces to be identified in Ireland or Britain.

Specialist studies which began at Ross Island in 1994 include pollen sampling carried out by Dr. Fraser Mitchell of Trinity College, Dublin. The objective of this research is to identify the environmental impact of this early copper mining, in particular the implications of fire-setting for wood consumption. One significant discovery in 1994 was made during pollen coring on the beach adjacent to the Blue Hole mine, in the eastern part of the Ross Island mine site. A submerged peat deposit was uncovered beneath 19th-century mine sediment. Test-pitting of this peat in turn uncovered wood and charcoal fragments associated with stone mining hammers. Further excavation will need to be carried out at this location. However, this evidence would appear to support 19th-century references to the working of the large Blue Hole mine in "ancient" times. This suggests that the Bronze Age mining activity at Ross Island may have extended right across the extent of the 19th-century mine site.