The 'frozen in time' world beneath the hillsides of North Wales

North Wales Live

3 days ago

Hidden beneath a slate covered hillside is "a working world frozen in time" which very few get to glimpse. The slate industry employed close to 20,000 people in Wales at its peak in the late 19th century.
But nearly all the quarries closed over time as the more easily accessible supplies were exhausted and there was competition from overseas slate and cheaper roofing alternatives. The industry does remain in places like Bethesda and Blaenau Ffestiniog but the workers can now be counted in their hundreds rather than their thousands.
The scars of the trade remain on the sides of mountains - the grey a contrast to the lush green countryside. But beneath those hills - where men once toiled - lie the remnants of their working lives. Sign up for the North Wales Live newsletter sent twice daily to your inbox
"It was like the miners had just downed tools and left," said Sarah Parker, who went for an explore recently at Maenofferen, Blaenau Ffestinog.
Work at the mine was first started in the early 1800s. During the nineteenth century the quarry flourished and expanded, extending its workings underground and further downhill towards Blaenau Ffestiniog.
By 1897 it employed more than 400 people with almost half of those working underground. Slate was sent on the Ffestiniog Railway to be used on roofs around the UK and further afield.
The quarry was purchased by the nearby Llechwedd quarry in 1975. Underground production at Maenofferen ceased during November 1999 and with it the end of large-scale underground working for slate in north Wales.
Sarah Parker, who loves to explore the natural and man made surroundings of Wales, described her visit. She said: "Deep beneath the mountains of North Wales lies a world that few ever get to see. As you step inside the old abandoned slate mine, everything changes — the air grows still, the light disappears, and silence surrounds you.
"It's eerie, beautiful, and genuinely unsettling. I wouldn't recommend going in unless you're fully prepared — it's unstable, dark, and incredibly dangerous in parts. There are deep drops, crumbling floors, and collapsed tunnels that make you realise how unpredictable these old places can be.
"But for us, it was an unforgettable adventure. With torches lighting the way, we passed rusting machinery, scattered tools, and the remains of a working world frozen in time — like the miners had just downed tools and left. Some of the underground chambers are vast, towering and echoing like hidden cathedrals deep within the earth.
"It's humbling. You feel the weight of history all around you — a glimpse into the lives of those who toiled in darkness.
"And a reminder of how quickly nature begins to take things back."
She reminded these were not places to be taken lightly and these sites contain numerous risks.
Above ground she also went around the cutting sheds where much of the skilled work was done.
Sarah said: "The abandoned slate cutting sheds here are like something out of a film set — rusted machinery still in place, decaying timber beams, and moss slowly reclaiming everything.
"Wandering through the remains of the old slate works, you can almost hear the echoes of the past — the clatter of slate being cut, the grind of machinery, and the rhythm of hard work that once powered this entire area.
"It's eerie, peaceful, and absolutely fascinating.
"Getting there involves a bit of a climb through the quarry terrain, so decent footwear and a good sense of direction are a must. The slate is sharp and unstable in parts, and as always with abandoned industrial sites, it's vital to stay cautious and respectful — the buildings are crumbling, and there are steep drops and hidden hazards everywhere.
"Still, for lovers of industrial history, urban exploration, or just dramatic, off-the-beaten-path places, this is a powerful place to visit. Maenofferen isn't just an abandoned quarry — it's a piece of Welsh heritage slowly being reclaimed by nature."