NPRNTitleType Of SiteArchivesImagesNPRN400427TitleMaenofferen Slate Mine, Blaenau Ffestiniog (Maen-Offeren; Maen y Fferem; Maen Offeren)Type Of SiteSLATE QUARRYArchives146Images136NPRN415947TitleUnhookers Office, Maenofferen Slate MineType Of SiteOFFICEArchives8Images8