Cwmorthin Slate Mine

Cwmorthin Slate Mine occupies a remote valley high in the mountains of Snowdonia, where slate quarrymen carved vast underground chambers and galleries from the living rock. Operating from the early 19th century until abandonment in the 1970s, Cwmorthin was never as commercially successful as nearby quarries, but men still labored and died extracting the valuable slate. The work was extraordinarily dangerous—rockfalls, equipment failures, and the ever-present threat of flooding from the mountain streams claimed numerous lives. Today, the site stands abandoned, accessible only by a long hike through the mountains, its underground workings partially flooded and creating one of Wales’s most atmospheric and haunted industrial ruins.

The vast underground chambers of Cwmorthin are the focus of intense paranormal activity. Urban explorers, historians, and curious hikers who venture into these cathedral-like spaces report hearing the echoing sounds of quarrying work—the distinctive crack of slate being split, the ring of chisels on rock, and men shouting instructions in Welsh. The acoustics of the enormous chambers amplify these phantom sounds, creating an overwhelming sense of the mine still operating. Witnesses describe seeing lights moving in the depths of the flooded lower levels, and shadowy figures working on the slate faces high above the water. The temperature drops dramatically without warning, and some visitors report feeling watched by hostile presences that resent the intrusion.

The most disturbing reports come from the flooded sections of the mine. Divers exploring these submerged workings describe an overwhelming sense of dread and malevolence, with some claiming to have seen faces in the rock walls and heard voices calling through the water. Equipment malfunctions are common, and several divers have aborted explorations due to inexplicable panic attacks. On the surface, the ruined barracks where quarrymen lived in harsh conditions echo with the sounds of Welsh hymns and work songs. The incline tramways, which transported slate down the mountainside, manifest the sounds of loaded drams descending and the shouts of men managing the dangerous operation. The most frequently reported apparition is of a quarryman in Victorian-era clothing standing at the entrance to one of the main underground chambers, his face showing the exhaustion and resignation of a man trapped in dangerous, poorly-paid work. Cwmorthin’s isolation intensifies its haunting—the ghosts of Welsh quarrymen remain alone in their mountain valley, forever splitting slate in the darkness beneath Snowdonia’s peaks.