The remains of the Cefn Cam Slate Quarry lie in a remote upland location to the west of Ganllwyd. The quarry itself lies on the east side of a complex of buildings sited close to a river crossing on the west. The building complex is surrounded by a wide outer polygonal earthwork enclosure depicted on County Series Ordnance Survey mapping.
The quarry was a series of pits worked successively over a long period. The slate was of a good colour and while not readily splitting, where it did it made a tough flexible product. Initially, everything was hand-dressed but at some point a water-powered mill was installed and, later, water-powered haulage. An abortive attempt was made to avoid haulage by accessing the workings via a tunnel. Finished product was transported east to the river by a well-engineered road. The quarry closed before 1953 though very small-scale hand re-working took place on the site at some point.
Visible remains (in 1991) include dressing sheds, workshop/office and mill with launder pillars adjacent, a possible barracks, and the manager's house with garden and underground food store.

Sources:
A.J.Richards, A Gazeteer of the Welsh Slate Industry (1991), p.156.
RCAHMW air photos.

David Leighton & Toby Driver, RCAHMW, 15 January 2015