There were three main ore bodies on this site - East Avoca, West Avoca and Cronebane. These were worked on both sides of the valley, making this site the second largest copper mine in Ireland. There is evidence to suggest that Avoca was worked for copper as long ago as the Bronze Age and possibly through medieval times. Its subsequent development shows how a mine can survive by turning to other minerals when the main deposits become exhausted. From the 12th century, the site was mainly producing iron but this had been exhausted by the end of the 17th century. Lead mining took over until about 1750, subsequently followed by copper mining until around 1812. Sulphur from the pyrites was produced between 1840-65, when the UK's major supply from Sicily was interrupted, and intermittently until 1949, especially during the two World Wars.