From the early Medieval period onwards, the iron industry in Europe experienced important technological changes that transformed the scale and nature of production and organization of ironmaking, ultimately leading to the Industrial Revolution of the 18th century. The use of water power to drive mechanical processes such as grinding, crushing, hammering and powering bellows, developed into the blast furnace and finery forge, which were introduced around the 12th century in Europe and 15th century in England. Ausewell Wood, a post-medieval iron-working site in Devon, South West England, is characterised by the presence of a blast furnace, areas of charcoal-processing, slag heaps, a long leat providing water to various channels and wheel pits, and further along the same river, an area dedicated to post-smelting operations. It is in this area that over twenty years ago a team from the University of Exeter and Dartmoor National Park carried out excavations; the excavated assemblage is the object of this study. Archaeometallurgical studies are employed here in combination with historical research with the aim to gain insight into the innovations and changes that occurred in the iron industry during the post-medieval period. To this end, over 2,750kg of slags and metal scraps were first subjected to macro-morphological investigation: the aims were to identify distinctive typologies and features peculiar to the technology represented on site and to link identified morphological traits of waste material to the spatial organisation of the ironworking area. The study of the assemblage in its entirety provided the first link between the remote part of the site where the blast furnace is situated and the excavated slag heap. The following chemical analysis campaign was then designed to investigate the connection between the two areas of the site and to reconstruct the metallurgical practices that generated the excavated slag heap. The selection of samples was devised accordingly: 56 between slag and metal pieces were studied using optical microscopy and SEM-EDS. The results of this research revealed that at the iron-working complex iron was smelted in the blast furnace and then carried over to the finery forge to be refined. This study not only provides the first secure evidence for this technology in the South West of England but also sheds new light on the artisanal origins and methods of fining pig iron.