Small underground working with adits.
Publications (2)
- Richards, Alun John (1991); Gazeteer of the Welsh Slate Industry, A; Gwasg Carreg Gwalch 978-0863811968
- Richards, Alun John, (1999); The Slate Regions of North and Mid Wales and their Railways; Gwasg Carreg Gwalch; 0863815661
