One of the many challenges we faced was to find a way of smelting the more complex
and problematical copper ore of chalcopyrite (copper iron sulphide).
The mines in Wales and elsewhere may have been producing chalcopyrite from the end
of the 3rd millennium BC, but there is very little archaeological evidence to show
us how they smelted it.
Simple furnace pits have been found within the Beaker mining camp at Ross Island
Mine in Killarney, Eire (O’Brien, 2004), and a reconstruction of one of these was
attempted using it both for roasting and smelting the sulphide ore.