Smelting of copper started around Neath under the Mines Royal Society c. 1584 .
The scale of the works increased dramatically from the early 18th century when Swansea displaced Bristol as Britain 's copper smelting capital .
Smelting of copper started around Neath under the Mines Royal Society c. 1584 but the scale of the works increased dramatically from the early 18th century when Swansea displaced Bristol as Britain 's copper smelting capital .