A series of quarries and mines, with tips, mills, tramways and other buildings extending over an area 950m E-W by 250m. Quarrying here is said to have begun in the 1840s. Features at the lower (W) end of the site appear to be the earliest, represented mainly by quarry (520408), spoil tip (520403) and mill (520405). The main phase of working began in the 1870s, and was known as Snowdon Slate Quarry in the 1870s: 'The Snowdon Slate Quarry on Bwlch Cwmllan ? has a profitable production of about 70 tons of slate a month, but it has machinery and capabilities for a much larger production. Some of the best blue slates in North Wales are made from the present quarries.' The works is shown on the 1891 OS, but the subsequent edition of 1901 shows it in more detail, but with little evidence of any further development. Some work continued in the early C20, since the 1920 OS map shows the enlargement of one of the tips (520423), on which a tramway was built from a quarry to the NE (520390). Work probably ceased soon afterwards and buildings are shown as roofless on the 1958 OS map.
D.C. Davies, A Treatise on Slate and Slate Quarrying, 1878, p 46.
A.J. Richards, Gazeteer of Slate Quarrying in Wales, 2007, pp 120-21.
R.Hayman & W.Horton, Yr Aran: an Archaeological Survey, RCAHMW unpublished report 2011, pp 9-15.
(http://www.rcahmw.gov.uk/media/327.pdf)

Recorded as part an Uplands Archaeology Initiative field survey, W Horton, H&H, 04/10/2011.