Report - Pen-yr-Orsedd Slate Quarry - Nantlle - October 2014

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The Lone Ranger

Safety is paramount!
Staff member
Pen-yr-Orsedd Slate Quarry - Nantlle



The Pen-yr-Orsedd quarry was one of the major slate producers of the Nantlle Valley, supplying over 10,000 tons of product in 1864. It was also the last quarry in the vale that commercially produced slate, closing in 1979.

In 1862 the quarry was connected to the Nantlle Railway, with 3 ft 6 in (1,067 mm) narrow gauge lines extended to all but the highest levels of the quarry. Most levels of the quarry had both 3 ft 6 in (1,067 mm) narrow gauge and 2 ft (610 mm) narrow gauge trackwork, many with mixed gauge tracks. The Nantlle Railway connection was used up until 1963, while the internal 2 ft lines continued in limited use until the end of quarrying.

The quarry was made up of a series of pits and its most notable feature in the later years was the complex series of four aerial ropeways known as 'Blondins', with Bruce Peebles electrical equipment of 1906. There is also a surviving engine house on the site.

It was one of the last slate quarries operating in North Wales and the last operating on the Nantlle area, finally closing in around 2000. However like many of the quarries in the area small scale working still goes on.

My Visit

This should have been a visit to Pen-y-Bryn Slate Quarry but due to me misinterpreting my hastily hand drawn map, lack of daylight and thinking I’d found a short cut I ended up here instead. In fairness they are next to each other and are separated by a huge pile of broken slates.

I should have turned up the hill sooner, but got sidetracked following the remains of the Nantlle Railway.


I passed a fair few derelict buildings before finding the remains of some type of winching system, there were a few of these spaced equally up the hillside with the remains of wire cables still in place.



This is a large building adjacent to where the weighbridge, wheel wash and porta-cabins, probably what was the site entrance.


Inside was a long driveshaft which would have provided the power to the machines in here.


Heading further up the hill was a large cluster of buildings, this was also near where work was still going on, just a digger and some sort of grading machine.


This appears to have been some sort of racking/storage area.


Inside one of the main buildings.


Some more storage.


There was a fair bit of interest in here.


The best was the remains of a slate cutting machine (I think?) still attached to its drive belt.


All the buildings had remains of the past in various states of decay.


Unfortunately the daylight ran out before I could get up the higher levels where a huge structure is just visible in this photo. Plus there was the man in the digger blocking the easy access to the upper levels.


On the way back out I found the way I should have gone in the first place to get to Pen-y-Bryn Slate Quarry; shame I missed it as I does have a few tunnels. Well it can wait until I’m in the area again as can the upper levels of this one.


Likes: hhh


28DL Full Member
28DL Full Member
Nov 4, 2014
This place was the subject of a TV series, hosted by Griff Rees Jones a few years back to find worthy preservation causes. I think the nearby Dorothea pump engine was also considered for similar preservation, but neither were successful. The outstanding feature of Pen yr Orsedd was the Blondins used to carry the slate out of the deep pits. Last time I went, one still survived, but not for much longer, I fear. Great shame.

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