Underground quarry at 1500’. Several adits to chambers.**

Several adits remain, providing access to chambers in the steeply dipping vein. The inclines from the adits, the compact mill, its retaining wall, and associated buildings are still extant. The tramway climbs around the shoulder of the hill to the top of the 1000 ft incline, noted as the highest two-pitch incline in any slate quarry system. The upper pitch drumhouse is ruinous, but the incline can be traced along the embanked inter-pitch manoeuvring loop, which originally connected to the lower pitch before extension to the Fron Boeth tunnel line. The lower pitch drumhouse, partially re-sited, remains in fair condition, with some original gear in situ and rope collars still visible on the ground.

Active in the 1840s, with chambers and sequentially numbered floors coordinated with the Moelwyn quarry on the opposite side of Moelwyn Mawr. Finished slate was transported by pack animals via Cwm Maesgwm to the Ffestiniog Railway at Penrhyndeudraeth. A small mill with an incline connection was constructed to process material. In 1863, a new incline to the mill was built and a rock-cut tramway was created along a shelf to the head of a two-pitch incline connecting to the Croesor Tramway. Closed in 1878, re-opened in 1886, and subsequently merged with Fron Boeth.