The Industrial Sublime

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Appreciating the Slate Landscape of Northwest Wales

This aerial view of the Gorseddau quarry shows how much infrastructure was needed to extract, work, and transport the stone. The stepped quarry at the centre is flanked on either side by a series of working platforms where slate blocks were turned into roofing slates. The four terraces to the left are connected by inclined planes, down which the worked slate was carried on rails on wedge-shaped carriages. Waste stone was taken by tramway along each terrace to be tipped off the edge, creating the characteristic lobe shapes fanning out from the terraces. CREDIT: RCAHMW

On 28 July, UNESCO added the Slate Landscape of Northwest Wales to its list of World Heritage sites, which currently number 1,154. Chris Catling reports on the reasons for this inscription and marvels at the human ingenuity that has left us with a remarkable landscape combining natural and man-made features – fully worthy of being included in the top tier of all heritage sites in the world.

When I open my computer to start work each day, I am presented with a screensaver photograph courtesy of Microsoft depicting some dramatically scenic and distant part of the world – often in the USA or South America. My reaction is often ‘Nice, but we have just as good in Wales’. Don’t just take my word for it: in hailing the inscription of the Slate Landscape of Northwest Wales as a World Heritage cultural landscape, journalists have been reaching for superlatives. Long-abandoned slate settlements in their upland setting have been compared to the 15th-century Peruvian citadel of Machu Picchu, while the silhouettes of windowless slate mills and engine houses have been likened to the romantically ruined shells of medieval abbeys and cathedrals.

The newly designated World Heritage landscape, with the component parts coloured red, along with the protected landscapes of the Eryri (Snowdonia) National Park (diagonal lines), and the associated Landscapes of Outstanding Historical Significance (blue). CREDIT: RCAHMW

Of course, it is not for aesthetic or poetic value that one is granted World Heritage status. You have to make a convincing statement of ‘outstanding universal value’ and demonstrate that your nominated site meets a number of strict criteria relating to integrity, authenticity, and evidential value. In order to do this, my colleagues at the Royal Commission on the Ancient and Historical Monuments of Wales – especially industrial archaeologist Louise Barker and aerial photographer Toby Driver – have worked with slate archaeology expert David Gwyn for the last five years to produce a hefty 472-page dossier of evidence to back the nomination.

You also have to produce a conservation management plan that will protect the special values inherent in the nominated landscape in perpetuity, and this task has fallen to a partnership of heritage institutions led by Gwynedd Council and including the Welsh Government, Cadw, the Eryri (Snowdonia) National Park, the National Museum of Wales, the National Trust, Bangor University, and many individual businesses, farmers, and landowners. It is to their credit that they have collectively succeeded in persuading some very hard-to-please heritage and conservation experts that this exceptional industrial landscape meets World Heritage criteria.

Now a major tourist attraction, the narrow-gauge Ffestiniog railway was built in 1836 to carry slate from Ffestiniog to Porthmadog Harbour. The 2ft (0.6m) gauge was a practical response to the challenges of creating a railway track in mountainous terrain. Contemporary with Brunel’s pioneering Great Western Railway, the Ffestiniog influenced the design of narrow-gauge railways around the world, including the Darjeeling Himalayan Railway, which was inscribed in the World Heritage list in 1999. CREDIT: Ffestiniog & Welsh Highland Railway


The Slate Landscape of Northwest Wales has been inscribed as a cultural landscape – a distinct category in World Heritage terms, defined as an area that represents an outstanding example of human interaction with the natural environment, embracing ‘the combined works of nature and of man’. The slate landscape has six component parts, all lying within the county of Gwynedd, amounting in total to precisely 3,259.01 hectares (and, yes, UNESCO does insist on that sort of precision). All six sites are further protected by a buffer zone comprising 250,400 further hectares of landscape that is protected either as part of the Eryri (Snowdonia) National Park or as a Landscape of Outstanding Historical Significance in Wales.

This belt-and-braces approach is intended to protect significant views within, towards, and out of the World Heritage landscape, and the precise boundaries have been a major point of discussion with UNESCO over the years. Initially, the team behind the nomination wanted to include working quarries, with the full support of the quarry owners. Sir Neil Cossons, a member of the slate project’s steering group, has long argued that industrial archaeology is a hollow shell without the living skills needed to maintain and run the protected heritage (see the profile of Sir Neil in CA 216).

In fact, some of those skills have survived within the World Heritage landscape. Visitors to the National Slate Museum in Llanberis can watch demonstrations of slate-splitting to create roofing slates, and there are two preserved steam-powered railways within the six component parts, both originally built to carry slate from quarry to port: the Talyllyn and the Ffestiniog & Welsh Highland railways. But the larger plan to include active mines and quarries fell by the wayside at an early stage because UNESCO experts felt that it would compromise the strict requirement to provide the highest levels of protection to the designated landscape.

Looming above the National Slate Museum in Llanberis is the Vivian Slate Quarry, which was opened in the 1860s and now survives with its stepped working floors and its system of transporter inclines intact. The inclined plane shown here was restored to working order in 1999, and is occasionally used to demonstrate how wagons loaded with worked slate going downhill pull empty wagons up from gallery to gallery. CREDIT: RCAHMW

The removal of Liverpool and Dresden from the World Heritage list demonstrates how strictly UNESCO polices the conservation responsibilities that accompany World Heritage status, as do UNESCO’s warnings about developments in Bath, Edinburgh, and the Stonehenge landscape that they consider to be a threat to that status. UNESCO’s concern about the revival of dormant extraction rights in the Cornish Mining Landscape, triggered by the rising value of various minerals and rare earth elements, means that areas of the Welsh slate region with dormant but still valid mineral extraction rights have had to be excluded from this recent designation.

These exceptions aside, the slate landscape includes a very broad range of heritage assets, embracing hillside quarries, cavernous underground mines, and massive cascading waste-tips; the whole panoply of infrastructure needed to extract and work the slate, including engine houses, wheelhouses, and mills powered by ingenious water systems; the inclines and aerial ropeways used to carry raw and worked slate from remote hills to tramways, and the narrow-gauge railways capable of negotiating mountainous terrain as they carried worked slate to the harbours at Port Penrhyn and Porthmadog for shipment to all parts of the world.

Additionally, it includes the houses of the slate workers, chapels, institutes, schools, and a hospital, as well as the National Slate Museum and its collections, and the houses of quarry managers and wealthy owners, including Penrhyn Castle, the mock medieval pile constructed by the aristocratic Lord Penrhyn, now in the care of the National Trust. The intangible heritage of the Welsh language is not forgotten in the designation, either. As David Gwyn told reporters when the UNESCO decision was announced, slate production is the only large-scale industry in Britain conducted entirely in a language other than English.

Modern works above Blaenau Ffestiniog: pulverised slate waste is used for road construction and as an abrasive and powder in various household products. CREDIT: Kate Owen


There are many ways to experience the slate landscape, both easy and more challenging. Simply to drive along the A470 immediately north of Blaenau Ffestiniog will bring you face to face with one of the fascinating facts about the slate industry: that for every 10 tonnes of slate extracted from hillside and cavern, 90 per cent is waste and only 10 per cent is useable for converting into slabs or roofing slate. As a consequence, the most visible legacy of the industry is the massive heaps of slate waste that line both sides of this stretch of road. Right in the middle of these mountains of scree is the Llechwedd Slate Cavern, which is not part of the World Heritage landscape but is well worth a visit nevertheless, for the rare opportunity to travel by railway 500ft into a deep mine with an experienced tour guide and get a real feel for the human muscle and ingenuity that shaped Snowdonia’s miles of underground slate workings.

Other relatively effortless and enjoyable ways to learn about the slate industry include visiting Penrhyn Castle, near Bangor, or travelling on the Talyllin or Ffestiniog & Welsh Highland railways. The National Slate Museum is another important destination, though its displays are somewhat dated and are not as informative as the name suggests. Located in a former engineering complex built in 1870, it is more concerned with how mining machinery and tools were made and maintained than about the methods by which slate was extracted and worked; on the other hand, the (relocated) row of slate workers’ cottages in the museum grounds provides an intriguing insight into housing conditions at different dates between the 1830s and the 1960s. The Welsh Government has also recently announced its intention to invest in updating the site to create a new Museum of North Wales.

For a detailed insight into the archaeology of the slate industry, there is no substitute for reading David Gwyn’s award-winning book Welsh Slate and exploring the various parts of the World Heritage landscape yourself, perhaps by means of the 83-mile way-marked Snowdonia Slate Trail or by doing some of the shorter circular day walks described in the books of local author, Des Marshall.  

This is an extract of an article that appeared in CA 379. Read on in the magazine (click here to subscribe) or on our new website, The Past, which details of all the content of the magazine. At The Past you will be able to read each article in full as well as the content of our other magazines, Current World ArchaeologyMinerva, and Military History Matters.

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