The Slate Landscape of Northwest Wales

The Slate Landscape of Northwest Wales
Photo by Els Slots.

The Slate Landscape of Northwest Wales is a stone quarrying and mining landscape that was transformed during the Industrial Revolution.

The slate industry has been present here from the Roman period onwards. It grew significantly in the 18th century before reaching its zenith in the 19th century, when these Welsh quarries provided roofing materials and slate products throughout the world. They also innovated the associated technologies of quarrying and transport infrastructure (such as narrow-gauge railways) were also exported worldwide.

Community Perspective: The site is made up of 6 locations, of which Dinorwic (for its museum, located in an authentic building, and other more remote remains) and Llechwedd Slate Caverns (for an underground visit) are recommended. Squiffy has provided a comprehensive overview of its values and has visited 5 locations.

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UK - 30-Jul-21 -

The Slate Landscape of Northwest Wales by Squiffy

The single-track road to Cwm Ystradllyn wound further into the contours of the Welsh hills, the cottages and farmhouses becoming fewer and further apart with every bend. It was as if the terrain itself was muffling the intrusion of the modern world. A low rusted gate hung apologetically by a wooded dell through which a stream tinkled; it squeaked as I pushed it open. Cast-off shards of loose slate, as grey as a pigeon’s back, clinked sonorously beneath my feet as I climbed to slope. And there, at the top, surveying the wild moors, stood a towering structure. Four strong walls, three storeys high, punctured by rows of romanesque arched windows, only its roof missing. Nesting birds twittered from the gables and nodding glacier-blue harebells blanketed its foundations. The entire spectacle resembled a medieval Cistercian abbey. But what abbey would have a millrace cut into its floor for a towering but long-gone waterwheel? And what abbey would have a curving embankment, the remnants of a vanished rail line, climbing up to the second story? Abandoned and isolated on the moors, the ruin of the Ynysypandy Mill told its own story about the 19th century boom and bust that momentarily transformed the rugged and sparsely-inhabited mountains of northwestern Wales into the world’s main source for a very in-demand material: slate.

The UK has a rich and varied history. You might not realise that from looking at its UNESCO properties. By my reckoning The Slate Landscape of Northwest Wales is now the UK’s 10th site to be inscribed relating to the UK’s industrial heyday in the 18th and 19th centuries. Blaenavon and Ironbridge are testament to the industrial production and use in engineering of iron, the Derwent Valley Mills represent the adoption and expansion of the mill system, all key requirements of what is commonly referred to as ‘the Industrial Revolution’. The slate industry was not a driver of the Industrial Revolution but rather a fairly niche by-product: industrialisation required urbanisation, urbanisation required housing construction, housing construction required roof slates. Slates were tough, impermeable and fairly light. Bricks could be made anywhere. Slates could not; the raw material had to be extracted where it occurred naturally and fashioned into tiles before being transported to the new boomtowns springing up within the UK and eventually worldwide.

‘Fairly niche’ but no less fascinating. And I fully endorse the decision to list this site. There are in particular three themes that I see represented by this inscription: the changes wrought on a wild and unforgiving landscape, the technical solutions adopted in the quest for production, and the question of employer-employee labour relationships.

Firstly, the landscape. This is a tough and wild corner of Great Britain. Away from the coast, roads are still largely restricted to glacial valleys and faults making travel times longer than they otherwise would be. The demand for slate sparked a sudden interest in these mountains with large scale extraction beginning in the late 18th century. This was industrial quarrying rather than precise mining, excavating huge chunks of the landscape and leaving gashes that can be seen today. The main pit at Penrhyn Quarry was a mile long and 1,800 feet deep and Dinorwig quarry covered more than 700 acres. And people were needed to provide a workforce. Existing settlements ballooned in size. What is now Blaenau Ffestioniog was an area of scattered farmsteads at the end of the 18th century. By 1850 the town had a population of just under 3,500; by 1881 it stood at over 11,000. By comparison it has now shrunk back down to around 4,000. Porthmadog grew from a population of 885 in 1821 to over 3,000 40 years later. Thomas Telford’s London to Holyhead road (now the A5) opened up the Ogwen Valley when it was constructed 1815-1826. A chapel built alongside it in 1823 formed the nucleus of the new town of Bethesda. Tramways and railway lines were laid to transport the finished slate from the inland quarries to newly developed harbours such as Porthmadog or Port Penrhyn (or, indeed the Seiont estuary below Caernarvon Castle, though the Slate Quay there is not part of this nomination).

The railroads are perhaps the biggest extant sign of technical solutions. The Ffestiniog Railway was constructed in the early 1830s to connect the quarries at Blaenau to the harbour at Porthmadog 22km away. The route to harbour was originally powered solely by gravity and carried only two loads: finished slate and horses (the horses rode down as passengers and were then used to haul the carriages back uphill to Blaenau). This railroad transitioned to steam locomotives as did others linking the Penrhyn quarry to Port Penrhyn and the Dinorwig workings to the sea. Different solutions had to be used to extract the slate depending on the angles at which the veins reached the surface. At Dinorwig workers chewed away at the southwest face of Elidir Fawr mountain. At Penrhyn a huge pit was sunk vertically. At Llechwedd the vein vanished diagonally under the hillside so adits were sunk across at various levels to permit the mountain to be hollowed out from within. Inclined planes can still be seen linking levels of terracing, most obviously alongside the Vivian quarry at Dinorwig, and some of the more isolated abandoned quarries in the Nanttle Valley still have in situ remnants of over technology like the Cornish beam engine (to pump water from lower levels) and aerial cableways known as ‘Blondins’ (to carry quarried material across the excavations). And a lot of this development was homegrown. The National Slate Museum demonstrates how Dinorwig had its own lumber mills and forges producing everything needed on site, from tools to cogs for the machinery to window panes. Trains for the Ffestiniog Railway were constructed at its Boston Lodge workings and still ply the route as a tourist attraction.

Finally, what I love about this nomination is that it provides an insight into labour relations. My view is that the UK’s previous industrial nominations from this period paint a rosier view of employer-employee relationships than is typically warranted. In the Derwent Valley Mills we see Richard Arkwright constructing the market town of Cromford for his labourers. At New Lanark Robert Owen introduced welfare programmes. Titus Salt created his model milltown of Saltaire with chapels and sanitation but no public houses. The quarry owners in north Wales were not so philanthropic. The fortune of the Pennant family of Penrhyn in particular was made through plantations in the Caribbean and by all accounts their management style did not change much when the slave trade was abolished and they pivoted from slave plantations to slate quarries. When George Douglas-Pennant lost his parliamentary seat at the 1868 general election his father sacked 80 quarry workers who he believed had not voted in his favour (the secret ballot was not introduced until 1872). While the North Wales Quarrymen’s Union was proclaimed in 1874 at Craig yr Undeb (‘Union Rock’) on the shores of Llyn Padarn at Dinorwig the Pennants refused to recognise it. The Great Strike of Penrhyn from 1900-03 remains the longest industrial dispute in British history. The National Slate Museum at Dinorwig recreates a worker’s cottage in Bethesda at the time of the strike and this can be contrasted with the home of the Pennants themselves at the fantasy ‘neo-Norman’ Penrhyn Castle estate.


Visitors can reach the general area by train, principally the main north coast route from Chester to Holyhead. From there you will generally need to rely on local buses or have your own transport. Even then, the landscape means that travel from one component to another will be disjointed and take longer than you might anticipate based on distance alone.

The World Heritage Area is a serial site made up of six separate cultural landscapes, five ringing Mount Snowdon in northern Gwynedd and one more located a considerable distance further south beyond Dolgellau. This allows different aspects of the inscription to be explored.  Dinorwig and Nanttle Valley comprise unified core areas; the other four have separate nuclei connected by railroads. I would argue that three of these landscapes are the main attractions, with the additional three being ‘nice-to-have’s.

Component 1: Penrhyn Slate Quarry and Bethesda, and the Ogwen valley to Port Penrhyn

The main London to Holyhead road, the A5, runs through the Ogwen Valley, a gap between the Carneddau (the largest continuous stretch of land over 2,500 in the country) to the north and the rugged Glyderau to the south. The town of Bethesda, with its many nonconformist chapels, serves as the key community in the area. The land south-west of the A5 was owned by the Pennant family, the Lords Penrhyn (which is why the bulk of the 19th century town was built to the north-east, on freehold land). Their Penrhyn Quarry was once the largest slate quarry in the world and today visitors can tour it via army truck (£20 for a 90 minute tour, over-5s only meaning that it was not suitable for us with a toddler) or just fly overhead on the UK’s longest zipwire. The scale of the quarry is not immediately apparent from the road alas. The Pennants themselves lived at Penrhyn Castle and Garden (£11 for adults, £5.50 for children), now managed by the National Trust, and a visit is instructive to see the life of luxury the extraction and export of slate created for them (though they had already made a lot of money in the 18th century through their slave-worked Caribbean sugar plantations); happily the interpretation at the site does not shy away from examining these aspects though on our visit access to the interior of the castle was limited due to Covid restrictions. So we never got to see the one ton bed carved out of slate for a visit by Queen Victoria (fun fact: Vic refused to sleep in it as she said it reminded her of a tombstone. I would have liked to be there to see Lord Pennant’s face!)

Without your own transport you will need to get to Bangor (1hr 20 on the North Wales rail line from Chester – the route goes through Conwy if you want to see its castle en route). The No 67 bus from Bangor will get you to Llandygai (for Penrhyn Castle) in 10 minutes and Bethesda (for the quarry) in just under 30.

Component 2: Dinorwig Slate Quarry Mountain Landscape

Llanberis is the outdoor adventure capital of North Wales, sitting as it does beneath Snowdon, the tallest mountain in Great Britain outside of Scotland. From town you have great views across a pair of linked lakes (Llyn Padarn and Llyn Peris) to where the Dinorwig quarry was hacked back into the hillside. The scale of it is immense. A grand series of stepped terraces, a dirty grey mirror to the rice terraces of the Philippine Cordilleras back Llyn Peris. The National Slate Museum (free entry, prebooking still recommended as of July 2021 due to Covid restrictions on numbers though barely enforced on our visit) now occupies Gilfach Ddu, the former workshops of the quarry. I found it managed to be both educational enough for me whilst also entertaining enough for my 5-year old son – highlights include recreated workers’ cottages from different eras, a huge waterwheel and slate-splitting demonstrations. Following the Vivian Trail through the neighbouring Llyn Padarn Country Park (turn right from the Museum and cross the road and railway tracks gives views of the terraces of the Vivian Quarry, the incline down which finished slate tiles were lowered to lakeshore and the former accommodation blocks of the Anglesey Barracks. The Quarry Hospital lies just a short walk further around the lake although opening times seem pretty oblique at present. A truncated remnant of the original railway that once ran down to the sea still offers short steam tours on the Llanberis Lake Railway (currently £25 for a private compartment seating up to six – we chose to have a ride on the Ffestiniog Railway instead).

Without your own transport you will again have to make for Bangor. Buses leave for Llanberis from right outside the train station and take about an hour (an alternative would be a 30 minute bus ride to Caernarfon to tick off another castle and then a further 30 minute bus ride from there). I would recommend yopur own transport though to ensure you can drop down into the valley from the east through the spectacular Pen-y-Pass and see the landscape and the scale of the Dinorwig workings opening up before you. Llanberis does have numerous carparks, all of which seem to charge different amounts. My non-exhaustive investigation suggests that the carpark right outside the Museum looks best value.

Component 3: Nantlle Valley Slate Quarry Landscape

I’m afraid our visit was limited to driving through Nantlle Village (pretty undistinguished; some quarrymen’s terraced housing to the south of the road and views of slag heaps to the north) while our children slept in the back seat. The wider quarry landscape beyond the village sounds interesting with some relict industrial machinery like a Cornish beam engine and ‘Blondin’ aerial ropeways. Theoretically it should be possible to get here on public transport (bus from Bangor or Caernarfon to Penygroes, followed by a second bus to Talysarn or Nantlle). I’m not sure I would bother though.

Component 4: Gorseddau and Prince of Wales Slate Quarries, Railways and Mill

Like Nantlle, this component is in no-way a ‘must see’. It is not as important as Penrhyn, Dinorwig or Blaenau Ffestiniog / Porthmadog for a very simple reason – the quarries in this area were failures. Attempts to quarry slate here failed miserably despite the effort and money expended. All that remains of the worker’s village of Treforys is the bare footprint of three streets of houses mouldering on the moorland. However, for those driving on the A487 between Porthmadog and Caernarfon a brief detour north on single track roads towards Cwm Ystradllyn is worthwhile if only to gape at the ruins of Ynysypandy Mill. The skeletal three-storey structure was built some distance away from the quarries due to the lack of running water required to power its overshot waterwheel and slate was brought to site via railway (seen entering the mill from the right in the photo above). All that remains of it now is a roofless husk on a hillock still strewn with shards of discarded slate but its resemblance to a monastic abbey is highly romantic (and overseas visitors may appreciate the chance to photograph it alongside a classic red British telephone box). Entry is via a gate (labelled Pont y Pandy Mill) by the bridge to the left of the phone box. I believe it is possible to drive further on even smaller roads to reach Gorseddau quarry and the remains of Treforys but I didn’t want to risk my wife’s goodwill (or our car’s suspension) any further.

Without a car you’re looking at a lengthy bus ride to Penforma (70 minutes from Bangor, 45 from Caernarfon) followed by a walk of well over an hour either way just to reach the mill, which seems extreme for a photo opportunity.

Component 5: Ffestioniog, its Slate Mines and Quarries, ‘city of slates’ and Railway to Porthmadog

Blaenau Ffestiniog proclaims itself to be ‘the slate capital of the world’ despite the fact that production here (as elsewhere in North Wales) is but a fraction of that at the end of the 19th century. It is a horseshoe-shaped town, fitting itself to the topography and backed by a landscape of grey crags and spoil heaps. The town itself is inscribed and we stayed in a terraced house in Manod, its eastern leg, but it currently has little outstanding to show for it.

The slate veins here sloped down from the mountain tops meaning that extraction from the surface risked bringing overhangs toppling down. As a result access to the veins was by adits through the rock with the slate being carved out within the mountains itself. The Llechwedd Slate Caverns provides an informational look at how this occurred through its Deep Mine Tour (£60 for up to four people). Neighbouring Zip World offers trampolining or canyoning in other sections of the mines. Mindful of the continued risk of Covid in areas with limited air circulation we regretfully decided to skip these attractions.

The Ffestiniog Railway links the town to the coast at Porthmadog. Heritage steam trains still ply the original route (with one exception where a diversion had to be built in the 1970s to avoid a new reservoir). Annoyingly, all return trips start and end at Porthmadog – it is impossible to book a ticket from Blaenau to Porthmadog and back. Depending on the day, trips may go only part way. We paid £60 for a private compartment for two adults (partitioned off from a larger carriage for Covid reasons) plus £1 for an additional child for a return trip to the spiral above Duallt station. The journey is very jolly, across the narrow ‘Cob’ that turned the broad Glaslyn estuary into a polder and permitted the construction of port facilities in the deeper channel remaining. You pass several rail worksheds and quarry warehouses before the pull uphill along the valley edge. Upon reaching Duallt we then came back to pause for an hour at Tan y Bwlch station, which wasn’t quite long enough to sprint down to see Plas Tan y Bwlch (home of the quarry-owning Oakeley family) itself. The trains that transported us, the 1864 Palmerston and the 1867 Welsh Pony (used for a bit of extra oomph up the track between Tan y Bwlch and Duallt) are original to this line. In Porthmadog itself the harbour from where slate was exported is now a rather pleasant marina.

Blaenau is actually still connected to the UK’s rail network. It is therefore the most accessible centre for exploring this WHS for those without their own transport because it is served by regular trains. If coming in from Chester you will need to alight after 50 minutes to change trains at Llandudno Junction (or the very cunning could stay on one further stop to Conwy, explore the castle and city walls there, and then walk back over the bridge for a mile to reach the interchange) and then travel for an hour down the exceptionally scenic Conwy Valley line. But with the Ffestiniog Railway only serving the town infrequently you still need a 30 minutes bus ride down to Porthmadog, which is itself 70 minutes by bus from Bangor.

Component 6 (Bryneglwys Slate Quarry, Abergynolwyn Village and the Talyllyn Railway) is located well to the south of the other components. Tywyn, for the Talyllyn Railway, is an hour by road or 80 minutes by mainline train from Blaenau. We didn’t even try to visit.


World Heritage-iness: 2

My experience: 3

(Visited July 2021)


Austria - 23-Dec-20 -

The Slate Landscape of Northwest Wales by Hubert

“To steal a mountain” was the title of the introductory film in the National Slate Museum in Llanberis. And if you look at the mountainside above Llyn (Lake) Peris, you understand how this is meant: the Dinorwic quarry gapes like a giant wound in the scenic landscape of the Snowdonia Mountains. I was torn between two opinions. On the one hand: the slate industry is not yet represented on the WH list, and Wales has a large number of original remains to fill this gap. So clearly pro inscription. But on the other hand: Should this ugly industrial landscape really be preserved? Or should we hope nature recaptures all of this as soon as possible?

The Slate Industry of North Wales is scheduled for nomination in 2021. In May 2017 we spent five days in Llanberis. Our main goal was to hike in Snowdonia National Park, but there was also enough time to visit some sites of the slate industry. There is not much left in Llanberis from the heyday of the slate industry. Today the village at the foot of Snowdon summit is a centre for hikers and other outdoor activities in the national park.

The National Slate Museum was a good introduction to the topic of slate production. The museum is located at the former workshops of the Dinorwic quarry. Most interesting was the demonstration how the slate was splitted and cut to roofing shingles.
At the roundabout not far from the Slate Museum, a zigzag trail leads up to the Dinorwic quarry. The quarry was once the second largest slate quarry in the world, only the nearby Penrhyn quarry being larger. Dinorwic was closed down in 1969, the lower part is now used by a hydroelectric power plant, but the upper terraces are accessible (upper photo). On the way up we saw remains of machinery, winches and rail tracks, and ruins of quarry buildings. As an example: the Anglesey Barracks (lower photo), a double row of terraced cottages where the quarrymen stayed during the working week. Even from the ruins, you can sense the harsh and cramped living conditions in the 19th century. And we saw discarded rock, tons of it, slate wherever you look. No trace of "nature is recapturing the abandoned place".
The view from the top over the quarry, the lakes and the Snowdon Mountains is great. We enjoyed exploring the remains of the abandoned quarry. The hike was about 5 kilometers long with an altitude difference of about 500 metres, in most parts over slippery slate.

Only one day of heavy rain out of five days in the national park - not bad for North Wales in late May. And I wasn't unhappy about the one day with bad weather because I was able to convince my friends to visit another site of this TWHS: the Llechwedd Slate Caverns near Blaenau Ffestiniog. Here, the slate was mined underground, in contrast to the open quarries of Dinorwic and Penrhyn. This could be due to the fact that the deposits originate from different geological periods: Llechwedd from the Ordovician, the more northern deposits around Llanberis from the Cambrian.
A narrow-gauge tramway descends 150 meters below ground to the slate caverns. The tour leads through a network of tunnels and large chambers. The slate mine resembles more a salt mine than the narrow galleries of a coal mine or an ore mine. However, the first thing we saw when we got off the railway were boxes of cheddar, Cavern Cheddar. The cheese is matured down in the mine for 11 months. You can buy it in the souvenir shop, and of course, we tasted it. So you can choose between two souvenirs: the Cavern Cheddar (more tasty) or a roof shingle made of slate (longer durable).

We had short stops at a few other locations that might be part of the nomination: the ruins of the Ynysypandy Slate Mill, a large mill building and freely accessible; the Dorothea quarry in the Nantlle valley, another abandoned slate quarry; and Port Penrhyn, once the main port for the shipment of slate, but today nothing reminds of that time.

In recent years industrial and technical sites have been quite successful at the WHC sessions. Thus, I would expect inscription for the Slate Industry in North Wales in 2021.

Thomas Harold Watson

United Kingdom - 30-Apr-20 -

The Slate Landscape of Northwest Wales by Thomas Harold Watson Of all the tentative listed sites I have visited as of yet, this is easily the most deserving of a whole heritage status. The slate industry is not currently represented atall by UNESCO and after driving through towns completely made with slate (the roofs, fences, gravestones and pretty much anything else you could think of) we visited the mines, which were even more fascinating. I don’t often want to return to many places, but this is one I definitely look forward to going back to, even if it’s just for their underground trampoline park! My 2 year old daughter and newborn son were also allowed down with my partner and I, but the whole time we felt completely safe, so do not worry about anything if visiting!

Read more from Thomas Harold Watson here.

Els Slots

The Netherlands - 09-Mar-20 -

The Slate Landscape of Northwest Wales by Els Slots

The Slate Landscape of Northwest Wales is the UK’s nomination for 2021. It will be a serial site with 7 components. Each of the components consists of a number of ‘elements’ – the most noteworthy “physical features which embody the attributes of Outstanding Universal value”. That value is to be found in (ii) the technology transfer to continental Europe and the USA, (iv) the dramatic impact of large-scale exploitation of natural resources and (v) the legacy of the industrial workers and their settlements. Its official name has been changed from “Slate Industry ..” to “Slate Landscape”, obviously emphasizing the cultural landscape approach.

I visited one of the components, the town of Blaenau Ffestiniog, on my way to the Gwynedd Castles in 2011. I’ve got a couple of photos left, but I must admit that I did not write up anything about the side trip and I can remember almost zero. What I see when I look at those photos again is a town that could only be in the UK: straight rows of similar stone houses (cheap housing for the quarrymen), a fish and chip shop, an Anglican church (they call it “Church of Wales” over here), a WWI memorial. It is surrounded by steep natural hills and man-made waste dumps. All photos appear to be taken in black-and-white as grey is the prominent colour of it all (including of course the slate roofs).

At the center of the town lies a railway station, which is the terminus of a narrow-gauge heritage railway. It was originally built to connect the quarries with the sea. The railway tracks and the “sense of arrival” (when doing so by train) are prominent features in the WH nomination. Most of the photos that I still have are railway related, so it must have been the town’s most impressive sight. In hindsight, St. David’s Church (now advertising bilingual services but in the past all churches preached in Welsh) and the market hall with interesting architecture might have warranted a closer look.

Desk research in 2020 reveals that there is a (slightly outdated?) nomination website available in Welsh and English, and the Management Plan can be found online as well. It is all well-presented and I don’t think there will be many objections getting it inscribed. But just as with my short visit, the presentation does leave an aftertaste of “Is this special enough?”. There was no element mentioned where I’d would be really interested enough to go back for a ‘proper’ visit. There’s the social history of course and the exploited landscape - this recent work might be an interesting read to get a better feel for the Welsh Slate history. Excerpts are readable for free online.

In ICOMOS’s Filling the Gaps document of 2005, that had the goal of identifying under-represented categories, post-Industrial Revolution technological properties located in Europe and North America were considered “overwhelmingly” present already. However, in the years since several more have been added to the List. Among those is for example the Cornwall and West Devon Mining Landscape which is geographically and thematically close to the Welsh Slate Industry Landscape. One of its arguments in the comparative analysis was that tin mining was not represented yet, and – indeed - slate mining also isn’t. But do we really need all imagineable resources represented?

Jakob Frenzel

Germany - 10-Jun-18 -

The Slate Landscape of Northwest Wales by Jakob Frenzel

March 2018 - In the afternoon we reached Snowdonia. Amazing Nationalpark and still covered in snow.

All houses in the valleys were covered with slate and even the walls were made from slate. Certainly an important raw material in that area and we learned Wales is the biggest exporter of slate. We took a short hike along Dinorwic Workings and discovered the impact of the industry here.

Next morning we still visited Bangor University.


UK - 29-Oct-17 -

The Slate Landscape of Northwest Wales by Solivagant

I don’t normally review sites from UK but, having just returned from a visit to the “Slate Industry of N Wales” T List site, I was surprised to note that it has not yet been reviewed at all. Since it is relatively easy to take in whilst visiting Gwynedd Castles and Pontcysyllte Aqueduct, WHS travellers might find the following info of use.

Just as S Wales is synonymous with “Coal”, N Wales is significantly linked to “Slate”. In the 19th C, Welsh slate roofed the burgeoning housing of London and elsewhere in UK and was also exported around the World - peak production was around 1831-78. Nowadays only some small scale production continues. The 7 areas identified for possible inscription follow a pattern set by the Devon/Cornwall mining site WHS - a number of mines, together with some towns/villages, often in the form of a cultural landscape, a port and some railways. For good measure add a 19th C Industrialist’s stately home and a university founded for the working class. These are scattered across N Wales and you will have to decide where to put your time and effort! It is perhaps worth mentioning a couple of things about slate extraction – first it can be carried out “open cast” in quarries or underground in mines. Both are represented within the 7 areas – our choice was to see an open cast example. These are spectacular in size when viewed in terms of the technology available and the humans who created them. Having recently visited 2 WHS silver mines in Slovakia and Poland we didn’t feel the need for another underground trip! This may have been a mistake since the underground quarries contain huge caverns with lakes unlike the small tunnels of the silver mines! Second, the process of producing 1 tonne of good slate “tile” generated around 9 tonnes of waste. This latter was dumped on the hillsides so, as well as vast “holes” created by the extraction, you get enormous spoil heaps.

We concentrated on “Welsh Slate Museum. Dinorwic Workings”. Dinorwic was the second largest quarry and is situated in the heart of Snowdonia just outside the honeypot location of Llanberis. Here walkers and climbers gather and the Snowdon mountain railway sets off up Wales’s highest mountain (a mere 1085 m high but not to be underestimated on some of its routes and in some weather conditions). The quarry’s 19th C engineering workshops have been turned into the “National Slate Museum” of Wales. This is “Free to enter” (but £4 to park a car), and is well worth visiting to help understand what you see around you and the working conditions and culture of the miners. The quarry contained 2 main areas and each has left a giant gash in the mountain face (photo). Up the mountain-side are a series of levelled areas leading to ever higher quarry “faces” which allowed slate to be extracted from multiple levels at the same time. It was reduced in situ to standard size roof slates (men only got paid for "good" finished slates and worked as small teams covering all tasks from initial extraction. They then shared the final payment). Waste was dumped and the slates were moved from each levelled area to “ground” level on rope inclines, one of which has been restored (look for “V2 Incline”). From there it was transported the c8 miles to the port by narrow gauge (2 ft and later 4ft) railway. This has been reconstructed as a “tourist attraction” running alongside Llyn (= “lake”) Padarn but adopting the narrow internal quarry gauge and using reconditioned quarry locos. The faces themselves have become a climber’s “Mecca” offering a wide range of climb difficulty through to some which have only been completed a handful of times. At the foot of the mountain next to the mining museum the lowest levels have become a lake deep enough (18m) to be used as a scuba diving training area. There are numerous walks in the area including some which ascend the quarry by footpath and lead to some quite atmospheric un-restored working areas with rusting equipment which looks untouched since the last miner left it over 50 years ago! Have a look also at the “hospital” dating from 1860 and paid for by the workers’ own contributions – a “mortuary” building is next door! We parked for free at 53.115489, -4.113017 from where there is an attractive 15-20 minute walk to the Slate Museum which provides fine views of the quarry, the lakes and also a chance to visit the 13th C Castell Dolbadarn which was the highly romanticised subject of a painting by JMW Turner. The museum has numerous displays set in the original “rooms” e.g the Workers’ canteen, the largest working water wheel in UK, a foundry etc etc and provides demos of e.g Slate splitting. Although it also has a row of miners’ cottages transported from another location it is not primarily a “skansen” consisting of such gathered examples. It and nearby walks could easily fill 3 hours or more.

The other major northern “quarry” identified for inscription is at Penrhyn in the Ogwen-Cegn Valley section (situated south of the Slate mining town of Bethesda - it isn't clear if that town itself would be included). This was even bigger than Dinorwic (“At the end of the nineteenth century it was the world's largest slate quarry; the main pit is nearly 1 mile (1.6 km) long and 1,200 feet (370 metres) deep, and it was worked by nearly 3,000 quarrymen.”) and still employs around 170. Its main “up front” visitor attraction is Europe’s longest and fastest zip wire which travels for over 1 mile over the quarry hole and lake. But there would appear to be some interesting walks as well all the way from (or to) the Slate port of Port Penrhyn, taking in Penrhyn Castle built for the owner of the mine. The structure, built around a 14th C fortified manor house, is considered a particularly fine example of early 19th C “mock Castles” and reflects the monies made from slavery and slate by the Pennant family. You could also take in Bangor University’s Neo-Gothic building from 1911 which seems to be intended for inclusion. But I am not sure it would be worth it – we just looked at on the Bangor skyline. The university was founded in 1885 but its original home has been demolished and its tangible connection to the rest of the site is perhaps a bit thin (E.g this report of the opening of the new building “there was then a procession to the college including 3,000 quarrymen (quarrymen from Penrhyn Quarry and other quarries had subscribed more than 1,200 pounds to the university)”).

Instead we travelled south east around 27 miles to the Ffestiniog Slate Landscape. Here there are several more “pay to enter” attractions – the underground mine visit, another (!) zip-wire and an “off road Quarry Explorer” – namely a 4x4 army truck to take you to the top of the quarry. These are not "cheap" - a standard underground tour is £20 though, if you plan ahead and book/take an early one, this price is halved. Even if you don’t want any of this (we didn’t!), the town of Blaenau Ffestiniog itself is worth visiting. It was only created in the early 19th C and is a “slate town” par excellence, a raison d’etre it is trying to replace with tourism. Around 85% of the population are Welsh speakers. It lacks significant buildings, but still provides an authentic atmosphere with its remote setting in wild countryside within which the grey spoil heaps almost “disappear”. Indeed if one knew the likely boundaries intended for the “slate landscape” there are a number of ghost slate villages in the surrounding hills which could be worth walking to (Cwmorthin looked interesting on a flyer we were given). The T List entry suggests that the narrow gauge steam railway which terminates at the town would be included. This makes its way up the 950ft from the coast at Porthmadog via a twisting route through attractive scenery with regular services provided by authentic steam locos. We didn’t take the train but did stop off at Tan-y-Bwlch station, where “up” and “down” trains pass each other on this single track line, in order to see 2 trains at the same time! The T List entry given to UNESCO also refers to the intention to include the “early hydro-power station”. But why – it only dates to 1963 and its prime factor of interest is that it is a “pumped storage” station? This uses more energy than it creates but it can produce 360 mw “on demand” and thus saves on “peak power” investment. It doesn’t really seem relevant to the OUV of the site?

So - what are the chances of inscription? Well, having experienced many of the other “Industrial Heritage” WHS around the World, I don’t see that this one is any less valid – indeed rather the opposite! Slate quarrying isn’t represented at all (Syracuse has significant ancient stone quarries and Italy also has the Carrara Marble Quarries on its T List though it would appear that it intends presenting these also as an archaeological site rather than as an industrial one), whilst there are numerous Silver mines! I found the Dinorwic location particularly worthwhile both for its museum, located in an authentic building and other remains, particularly the more remote ones. In common with many UK WHS there is a fair degree of “commercialisation” in the presentation of some of the “experiences” at some locations but I don’t see that these interfere with the overall OUV. The potential nomination has a “Web Site” and this contains an assessment of potential economic outcomes from a successful bid (It is interesting to see what the “drivers” are behind local support for the WHS initiative (i.e Jobs!) but, when I spoke to several “locals” in Blaenau Ffestiniog, none of them was aware of the intention to gain WHS status! I also found the arguments in the report for the potential economic benefits of inscription rather unconvincing – using Vigan as a benchmark hardly seems relevant!) The only time scale info is this quote “A technical evaluation of the bid was presented to the DCMS in November 2015 for consideration by a panel of heritage experts. We received constructive and positive comments on the bid in early 2016 and are now working towards developing and strengthening the necessary documentation with a view to gaining a date from DCMS for final submission of papers to UNESCO.” With Scotland having been successful with the Forth Bridge in 2015, England with the Lake District in 2017 and apparently also pursuing Jodrell Bank for 2019 it would seem that Wales would have a good argument for progressing the Slate Nomination ASAP thereafter.

Site Info

Full Name
The Slate Landscape of Northwest Wales
Unesco ID
United Kingdom
2 4
Cultural Landscape - Relict

Site History

2021 Inscribed


The site has 6 locations

The Slate Landscape of Northwest Wales: Penrhyn Slate Quarry and Bethesda, and the Ogwen Valley to Port Penrhyn
The Slate Landscape of Northwest Wales: Dinorwig Slate Quarry Mountain Landscape
The Slate Landscape of Northwest Wales: Nantlle Valley Slate Quarry Landscape
The Slate Landscape of Northwest Wales: Gorseddau and Prince of Wales Slate Quarries, Railways and Mill.
The Slate Landscape of Northwest Wales: Ffestiniog: its Slate Mines and Quarries, ‘city of slates’ and Railway to Porthmadog
The Slate Landscape of Northwest Wales: Bryneglwys Slate Quarry, Abergynolwyn Village and the Talyllyn Railway.


The site has

Human Activity
Individual People
Religion and Belief
Science and Technology
WHS Hotspots
WHS on Other Lists
World Heritage Process