The copper mines, known locally as the Copper Caves, can be reached via the Kerry Way behind Staigue Fort House. They date from the Bronze Age, c 2,400-600 B.C. These sites are interesting both from a geological and an archaeological perspective.
There are three mines marked on the Ordnance Survey maps for the region; St. Crohan’s Hermitage, Coad and Staigue – all within walking distance of one another.
The mines at St. Crohan’s Hermitage and Staigue are both by rivers: the Behaghane and Staigue rivers. These cave-like mines have rich turquoise/green hues in the rock due to deposits of the green carbonate, malachite. The percolation of slowly dripping water through the copper-bearing rocks, followed by its evaporation, results in deposits of the dissolved carbonate in the fissures of the rock. Malachite is valuable as an ore of copper. The mine at Coad displays azurite mineralization.
At primitive mine sites, two principal areas of activity can be identified:ore extraction which is known as mine working, and the ‘spoil dump’ where preliminary crushing and sorting of the ore was undertaken. Rock debris was usually dumped in heaps outside the mine entrance.
The smooth shape of the mines suggests that the copper was extracted by fire-setting, a mining technique commonly in use up to the nineteenth century. Wood-fuelled fires would be lit against the rock face. The heat would make the stone brittle and therefore easier to break away using stone cobble hammers and mauls. These tools have not yet been identified at these mines.
The crushed ore may have been washed in the nearby rivers to separate the heavier metallic content. The rock would then be converted to metal through the process of smelting – burning the finely broken copper ore in a charcoal-fired pit furnace to produce droplets of copper metal. Smelting furnaces associated with these sites have not been found.
The existence of shafts and denuded spoil-dumps further along the quartz reef by St. Crohan’s Hermitage indicate that mining activity took place here in the nineteenth century. A drystone rectangular structure located adjacent to it may be related to later mining activities.
As to where the copper itself came from…It has been known for decades that the ordinary elements around us here on Earth arose in stars. Copper came to be after these stars expanded to become supergiant stars. They later exploded as supernovae, scattering the newly minted copper into space. Four and a half billion years ago, we got some of this copper.