Bryn Glas slate quarry was begun in 1890s and closed in the 1920s. It was briefly reworked in the 1960s. The earliest working appears to be below the main site, where a mine entrance and spoil tip (nprn 536985, 536984) are at the foot of later spoil tips. And above the main site is a small quarry (nprn 536939), with track (nprn 536940) leading to a spoil tip (nprn 536937), which is overlain by later working. At the main site is a quarry (nprn 536949) and two adits (nprn 536941, 536944), spoil tips (nprn 536942, 536945, 536950), a large mill (nprn 536943) and associated buildings (nprn 536920, 536928, 536946, 536947, 536948). A track or tramroad (nprn 536951) was the means by which slate was transported to the road to Llan Ffestiniog. The mill was steam-powered and the reservoir and leat (nprn 536917, 536918) that suplied the boiler have survived. A second site to the SE was connected to the main quarry and its mill by tramroad and incline (nprn 536930, 536938, 536931). The second site comprises a deep quarry (536934) and an adit (nprn 536932) re-used as a tunnel for removal of material, together with spoil tips (nprn 536933, 536935, 536936).
Recorded as part of RCAHMW Uplands Initiative Project, R Hayman, H & H, 24/01/2014.