Gallt-y-fedw quarry is located to the immediate east of Talysarn village, and close to Dorothea Quarry (NPRN 40569). It was worked as two small open pits and possibly operated on a small scale long before being developed in the 1850s. A steam incline raised material to a six saw-table mill, while finished product went out by an incline which crossed and then made a junction with the Nantlle railway. A rubbish run bridged the easterly Cilgwyn incline. Output was only a few hundred tons per annum with about 12 men employed. Unusually, saw tables were operated in the open air. A suction gas engine was installed in the 1920s, though never used. One pit ceased in 1870, the other continued until 1930. In later years it operated with the Dorothea quarry.
On a crowded site, visible remains (in 1991) include a small mill and several other buildings (40553), incline formations, possible launder pillars suggesting use of water power, a fine privy structure, and a shallow stone-lined pit of 30m diameter of unknown purpose.

Sources:
D.Gwyn, Welsh Slate: the Archaeology and History of an Industry (RCAHMW 2015), p.90.
A.J.Richards, A Gazeteer of the Welsh Slate Industry (1991), p.51.
RCAHMW air photos: AP94-CS 0996, 0998-9; AP945128/62, 64-5.

David Leighton, RCAHMW, 2 February 2015