A building within the Cwmrhaiadr Mine complex (NPRN 402599) shown on the 1891 Ordnance Survey map. The building had largely disappeared when the site was visited in June 2005, but it had stood on a terrace cut into the steep slope. The terrace is 15m southeast-northwest and 9m wide. The building stood on the eastern edge of the terrace and appears to have been no more than 5m square. Some revetting still remains and a tin shed stood on the site when it was visited in June 2005. J.J. Hall, Trysor, 23 December 2005