[1] Cwt y Bugail means "Shepherd's Hut", and was probably the only notable feature in the vicinity, and hence was used for the name of the quarry.

He ran Cwt y Bugail for the next thirty years and was the great-grandfather of Owen Glyn Williams who managed the quarry in the 1980s.

The receiver sold the quarry to Cadwalader Owen Roberts of Betws-y-Coed for a nominal sum.

Roberts reopened Cwt y Bugail in 1919 after the end of the First World War and worked it for three more years, but again the enterprise failed and the quarry closed.

[5] In 1961 the Cwt y Bugail company was taken over by a consortium led by Dafydd Price, who also purchased Graig Ddu which at this time was a much more productive quarry.

[5] A subsidiary of Ffestiniog Slate Quarry Ltd. purchased the land and mineral rights to Cwt y Bugail in 1985.

[7] Within the quarry were eleven or twelve inclines used at various periods to access the slate workings and tipping areas.

[7] These were connected to the mill via lightly laid tramways using bridge and flat bottom rail.

Although the majority of this track was laid to 1 ft 11+1⁄2 in (597 mm) narrow gauge to match the Rhiwbach Tramway, there is some evidence that the earliest tramways in the quarry were laid to 2 ft 2 in (660 mm) gauge.

The Dolwyddelan fault crosses the site from north to south immediately to the east of the main adits, and the veins end abruptly at its location.

The slate was of poor quality close to the fault (it was generally shattered), but improved westwards.