Cwm Du colliery and ironstone mine was worked from 1850 to 1908. It is depicted at work on the 1st edition OS County series (Glamorgan. XXVI.6/10 1877) and disused on the 2nd edition of 1899. St Johns Colliery was opened on the same site in 1910 (NPRN 435).
The workings extended for a kilometre along the Nant Cwm Du, with various shafts and levels connected by tramways. At the northern extremity, now in Dunraven Forest, a tramway reached out to a large ironstone quarry.
