ABSTRACT In 2021, Swansea University commissioned Black Mountains Archaeology Ltd to undertake a community archaeological excavation as part of a National Lottery Heritage Funded activity plan. The excavation was undertaken on the site of the former Hafod Plate Rolling Mill in Swansea, South Wales, UK, within which copper plates intended for both national and international shipment were produced between 1910 and 1980. The rolling mill represented one of the largest structures within the Lower Swansea Valley — also known as ‘Copperopolis’. Moreover, the mill formed part of the Hafod (and later Hafod-Morfa) Copperworks — one of the largest copper production sites in the world at the time. Within this article, the results of the 2021 excavation will be detailed. During the excavation, features associated with steam power supply, annealing, pickling and finishing were recorded. By comparing the excavation results with available cartographic and documentary evidence of the copperworks, this article outlines a detailed picture of the operations once conducted within the rolling mill, therefore bringing the mill back to life.