Substantial earthworks, including shafts and open surface workings, remain visible in the vicinity of Marian Ffrith, southeast of Tyddyn-y-cyll (SJ 0690 7820). In this area, haematite has been mined alongside chalcopyrite and lead. To the northwest of Tyddyn-y-cyll, additional shafts can be found on the slopes of Moel Hiraddug, where mining evidence has remained relatively undisturbed. In contrast, much of the mining landscape at Marian Ffrith has been erased due to land improvement. One of the few surviving features from Pennant’s time is a partially filled-in open working at SJ 0718 7798.

Evidence suggesting extraction dates back to at least the medieval period. Pennant (1991) noted that by the second half of the 18th century, long trenches in the area were already considered ancient, and he attributed them to an early medieval origin. He also recorded that Hugh d’Avranches, Earl of Chester (1071–1101), had a share in the iron ore mines of Rhuddlan Manor, which included Marian Ffrith, indicating that mining was taking place in the area over 900 years ago. While the Historic Environment Record (HER) previously attributed mining in this location to the 19th century, Pennant’s observations suggest that extraction began much earlier.