Wern Ddu

About the project

Wern Ddu Clay Pits SSSI

Wern Ddu Clay Pits was the very first site that BIGC worked on as part of its South Wales Coalfield Geo Heritage Project. We became involved with the clay pits back in 2006 when we were looking for a suitable site to demonstrate and test the viability of geological conservation of important sites within the South Wales Coalfield.

Wern Ddu had been designated as a geological Site of Special Scientific Interest in 1984 for the extensive exposures of 300 million year old, Carboniferous, Westphalian A, B and C Coal Measures Geology that outcrops here. Wern Ddu, a former opencast clay pit and site of an old drift mine, had become overgrown and derelict following the cessation of clay extraction in the mid 60’s. In the early norties, a group of passionate locals formed The Caerphilly Woodlands Trust (CWT) took ownership of the site and began developing footpaths and making improvements to the area to enhance the site for biodiversity.

The geology itself is of considerable importance being one of only two remaining places where these extensive sequences of Upper Carboniferous strata can be examined. This site, on the extreme south east of the coalfield, has avoided the high temperatures and deep burial that the majority of the coalfield was subjected post deposition. The result of this is that the mudstones are poorly consolidated and very clayey and the coal seams are very poor quality compared to much of South Wales.

Working in partnership with Countryside Council for Wales, The Forestry Commission and with the landowners the CWT, BIGC secured a small grant from Environment Wales and began a phase of geological improvement and access enhancement. We brought in some excavators and created new geological features and enhanced old, degraded and overgrown geological sections. Several coal seams were unearthed enabling us to better understand the stratigraphy of the site we created safe viewing areas where the geology could be safely studied.

Over the past few years BIGC has been involved with the development, monitoring and maintenance of the site. We’ve worked with the Caerphilly Woodlands Trust and a wider network of stakeholders to increase understanding of the unique geological importance of the Wern Ddu Clay Pits site.

In later phases of development at Wern Ddu BIGC has worked with Caerphilly County Council and local schools to develop some educational resources for the site. A teachers pack called Wern Ddu Rocks was produced, it’s available to download from this site and is aimed at Key Stage 2 teachers who wish to explore the Geology and Natural History of the area as part of a stimulating outdoor learning experience.

In addition to Wern Ddu Rocks and 8 point bilingual audio trail is available to download from this site. To accompany the audio trail we’ve designed and installed several interpretation panels which explain the geology, industrial history and ecological importance of the site.

About the site

Situated just off Van Road to the east of Caerphilly this site contains a network of relatively flat, well groomed footpaths. There is no parking at the Clay Pits itself so park at Coed Park y Van (five minutes away). For those travelling by car and using Sat Nav the nearest postcode for the car park is CF83 1UG

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