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Geophysical surveys (magnetic gradiometry, magnetic susceptibility and ground resistivity) have been undertaken over the area of the Pont-y-parc leadmine (3ha centred on ST 048823) and of the associated ore processing area (0.7ha around ST 050823.
The earliest identified feature is a leat to the north of the workings. Cartographic evidence suggests the leat arose from the Afon Clun to the east of the surveyed site (ST 0534 8248), and followed the edge of the floodplain westwards, passing along a line now buried by the northern edge of the cemetry, and across the old Cardiff-Llantrisant road along the north side of the curtilage of the later Pont-y-parc farm. The leat forms the southern boundary of the 18th century ore processing area adjacent to the farm. The leat is degraded adjacent to the embankment of the A4119, but reappears west of a spring interpreted as the collapsed mouth of a drainage adit constructed in 1756, which appears to cut the leat. The leat continues westwards as a well-developed earthwork and may bifurcate close to its termination adjacent to a small platform (ST 0472 8232). This platform has been interpreted as a medieval corn mill (RCAHMW 1982), but the geophysical survey demonstrated strong magnetic anomalies on the platform, and sheep scrapes showed a deposit including both iron slags (bloomery smelting and smithing) and lead mining waste on the platform edge, so the "mill" appears to have had an industrial function. The "mill" has unfortunately recently been damaged by a large pipe trench, cut without archaeological observation across the eastern side of the latform and through the leat. The slag deposit was exposed to the NE of the platform, close to the present riverbank, and yielded a single sherd of medieval Vale Ware. If the site were a medieval water-powered iron-making facility, it would be of national significance.
Reference
RCAHMW, 1982. An inventory of the ancient monuments in Glamorgan. Vol.3, Medieval secular monuments. Part 2, Non-defensive. Royal Commission on Ancient and Historical Monuments in Wales, HMSO.