The Slate Landscape of Northwest Wales

• Official Name: The Slate Landscape of Northwest Wales
• Location: Wales, United Kingdom
• Type: Cultural
• Year of Inscription: 2021

Based in the Snowdon massif in the northwestern Welsh county of Gwynedd, the Slate Landscape of Northwest Wales is a postindustrial countryside created by many decades of mining and quarrying. Its name is sometimes written as the “Slate Landscape of North West Wales,” and it is also referred to simply as the “Slate Landscape.” The landform’s name in the Welsh language is Mae Tirwedd Llechi Gogledd Orllewin Cymru.

World Heritage United Kingdom (UK) characterizes the site as a historical document representing profound social and economic transformation, capturing the geographical expression of a localized shift from traditional agrarianism to industrialization. Slate extracted from the landscape was widely used both in the UK and around the world, mainly in the construction of roofs and buildings. During its peak period of industrial activity in the late nineteenth century, the Slate Landscape supplied approximately one-third of all slate used in architecture and roofing globally.

The Slate Landscape was approved as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site by the organization’s World Heritage Committee in July 2021. It became the UK’s thirty-third UNESCO World Heritage Site and offset the downgrading of the UK port city of Liverpool, which lost its World Heritage Site status earlier in 2021. The Slate Landscape’s accession to World Heritage Site status marked the culmination of a years-long bidding and application process.

In approving the Slate Landscape as a World Heritage Site, the World Heritage Committee noted the site’s vast size and scale, cultural value, historically significant technological and industrial innovations, and the continued presence of well-preserved industrial equipment and engineering signatures. The specially developed railway systems used to transport slate extracted from the landscape to shipping ports on the Welsh coast were also highly influential, with similar systems being adopted in many places around the world including locales in Africa, Asia, Australia, and the Americas.

History

The Snowdon massif region has a history of quarrying activity dating to the era of the Roman Empire (ca. 27 BCE–476 CE). Following the Roman conquest of ancient Britain in 43 CE, the Roman Empire established a long-term presence in the British Isles. It was during this time that the earliest quarries appeared in Wales. Segontium, a Roman fort built in what is now the municipality of Caernarfon in the county of Gwynedd, contains slate mined from the Snowdon massif. The castle of King Edward I (1239–1307) in Conwy, Wales, also features Welsh slate in its construction.

Welsh slate was used in later centuries in select construction and restoration projects in Britain. Prior to the era of industrialization, slate was extremely labor-intensive to extract, and the prized rock carried very high economic value. As such, only institutions and establishments with elite wealth, such as the Catholic Church and the British monarchy, could afford to use it in significant quantities. This began to change during the initial phases of the Industrial Revolution (ca. 1760–ca. 1840).

During the Industrial Revolution, a confluence of factors combined to increase local and international demand for slate and make it easier to obtain. The rapid rise of mechanized and industrialized production facilities triggered sharp, sudden population increases in many British cities, with Manchester having a particularly important impact on the early development of the Slate Landscape given its relative proximity to northwestern Wales. This combination of industrial development and surging urban growth led to a strong uptick in demand for slate, which was used in the construction of factories, foundries, and the residential buildings erected to house workers. Around the same time, conventional approaches to slate mining and quarrying were changing as the result of the introduction of gunpowder. Slate extractors developed techniques that used gunpowder to blast and shatter large natural rock deposits into smaller pieces, which were then processed into narrow strips for use in construction and roofing. While the technique posed major dangers to workers and degraded large proportions of the rock it extracted, it represented a major improvement relative to legacy techniques.

Later refinements to mining and quarrying techniques brought further improvements, yielding higher proportions of usable slate while reducing risks to workers. These included ingenious feats of engineering that harnessed the force of moving water to free up large deposits of slate from natural landforms. Britain, which industrialized at a very rapid rate relative to other European and Western countries, also pioneered the widespread use of the modern steam engine. Trains powered by steam engines became capable of distributing extracted slate across far wider areas than ever before, fueling further demand for Welsh slate both in Britain and abroad. Ports were established on the Welsh coast to transport locally quarried slate to international markets, marking the further evolution of the Slate Landscape. These port facilities are part of the entire serial property recognized as a World Heritage Site by UNESCO, which includes six distinct regions that each have mines, quarries, processing sites of archaeological significance, active and defunct worker settlements, estates and gardens, and the signature narrow-gauge mountain roads and railways that form an iconic part of the Slate Landscape.

The 1787 establishment of the Great New Quarry near the highland village of Dinorwig (Dinorwic) marked an important early moment in the evolution of the Slate Landscape. This quarry developed into the epicenter of what became a major Welsh industry, employing more than three thousand mine and quarry workers during its peak in the 1870s. Domestic demand for Welsh slate peaked during Britain’s Victorian Era (1837–1901), with slate becoming a common feature of buildings and roofs constructed during the period.

The historical Welsh county of Caernarfonshire, which has since been absorbed into three modern Welsh counties including Gwynedd, was the most prolific area of the Slate Landscape in terms of its overall output during the Welsh slate industry’s peak in the late nineteenth century. During that peak period, Wales produced more than 80 percent of all slate in Britain. By the 1890s, the slate industry of Wales directly employed approximately 17,000 workers and yielded an annual output nearing 551,155 tons (500,000 metric tonnes) of usable slate. Changing market dynamics including the widespread availability of lower-cost imported slate led to the decline of the Welsh slate industry in the early twentieth century, which gradually drifted into inactivity by the 1970s.

Significance

The Slate Landscape earned its status as a World Heritage Site by meeting UNESCO standards associated with selection criteria ii and iv. Selection criterion ii covers high-impact cultural changes involving technological or architectural elements, while criterion iv acknowledges historically significant landscapes or important examples of architecture or technology.

UNESCO elaborates on both of these aspects in its official entry on the Slate Landscape of Northwest Wales. Regarding criterion ii, UNESCO writes that the Slate Landscape captures the legacy of industrial transformation through its human-influenced geography. According to UNESCO, this transformational period was most profound between about 1780–1940 and holds added significance because of the concurrent development of novel architectural styles and innovative technologies. UNESCO also acknowledges the global influence of the Welsh slate industry, noting that the widespread availability of slate had a profound impact on architecture and construction in many locales around the world during the 1780–1940 period. The Welsh industry also functioned as a pioneering transnational leader in slate production, with its attendant technologies and knowledge transfers informing the rise and development of similarly successful industries in the United States and other parts of Europe.

The iconic narrow railways linking Welsh mining and quarrying sites with nearby coastal shipping ports are another unique point of significance. These railways, which remain operational in limited capacity, directly inspired the design and development of similar railroad systems in upland and mountainous regions spanning multiple continents. These railway systems directly accelerated local economic development in the many areas where they were used.

With respect to criterion iv, UNESCO recognized the property not only as a quintessential example of a postindustrial mining and quarrying landscape, but also as a geographic region that relays a historically significant narrative about its evolution and purpose. The Slate Landscape bears evidence of the feats of engineering genius that facilitated the prolific water-powered extraction of slate from the Snowdon massif highlands, while its iconic narrow-gauge railways represented a major technological step forward at the time they were built. In these regards, the Slate Landscape captures the broader transformational character of Britain’s Industrial Revolution and the profound impacts it had on contemporary human society.

The Slate Landscape of Northwest Wales is also atypically well-preserved for a postindustrial landscape, with its physical markers and features giving clear indications of the varying dates and industrial processes that define the development and maturation of the Welsh slate industry. Boundaries protected under World Heritage Site status are all industrially inactive, making UNESCO officials optimistic about the Slate Landscape’s potential for long-term conservation.

Bibliography

“Story of Slate.” National Slate Museum, museum.wales/slate/story-of-slate/. Accessed 5 July 2022.

“The History of Quarrying: The Long Decline.” Gwynedd Council, 2003, www.llechicymru.info/IHistDecline.english.htm. Accessed 5 July 2022.

“The Slate Landscape of Northwest Wales.” United Nations Educational, Scientific, and Cultural Organization, 2021, whc.unesco.org/en/list/1633/. Accessed 5 July 2022.

“The Slate Landscape of Northwest Wales.” World Heritage UK, 2022, worldheritageuk.org/world-heritage-sites-uk-list/wales/slate-landscape-northwest-wales/. Accessed 5 July 2022.

“The Slate Landscape of North West Wales—A Bid for World Heritage Status.” National Slate Museum, 2022, museum.wales/slate/whatson/11382/The-Slate-Landscape-of-North-West-Wales---a-bid-for-World-Heritage-Status/. Accessed 5 July 2022.

“Wales Slate.” Gwynedd Council, 2021, www.llechi.cymru/home. Accessed 5 July 2022.

“Wales’ Slate Landscape Wins World Heritage Status.” British Broadcasting Corporation, 28 July 2021, www.bbc.com/news/uk-wales-57986167. Accessed 5 July 2022.