Small underground working that never produced product.

Two stone buildings. One structure is sunken and features stepped access alongside a discernible stocking area where finished or stored material would have been handled. The second building contains holding-down bolts for an engine, suggesting it housed machinery, possibly a saw. The site retains significant quantities of waste and trimmings, alongside some clear tramway formations used to transport material. Additionally, there are two small pillars of unknown purpose.

Cae Rhobin was a small, primitive open quarry situated on what was described as a difficult working site. The quarry operated intermittently over a long period, with its material being transported by tramway down to a separate mill area for processing. The quarry ultimately ceased working in the 1920s.