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Hetty Pit is a post-medieval and modern colliery located in Wales, protected as a scheduled monument by Cadw under reference GM459. The pit exploited seams within the South Wales Upper Coal Measures Formation, geological strata laid down during the Westphalian period of the Carboniferous. These rocks comprise alternating bands of mudstone, siltstone and sandstone interspersed with coal seams, ironstone and ferricrete, the iron-rich cemented material that formed where mineral-rich waters percolated through the upper coal measures.
The colliery represents the industrial heritage of South Wales coal mining, which transformed the region's economy and landscape from the late eighteenth century onwards. Pits such as Hetty operated within a geological setting ideally suited to deep mining, where multiple coal seams allowed extended working both vertically and horizontally underground.
The monument's designation reflects the archaeological and historical importance of coal mining remains in Wales. Such sites preserve evidence of the technological and social structures that sustained mining communities, from surface infrastructure to underground working practices. Hetty Pit contributes to understanding the industrial development of South Wales and the geological resources upon which that development depended.
Hetty Pit is a scheduled monument protected by Cadw under reference GM459. View the official record →
Hetty Pit is a post-medieval and modern colliery located in Wales, protected as a scheduled monument by Cadw under reference GM459.
Hetty Pit dates from the post medieval/modern period, and is classified as a colliery. It is one of over 32,000 scheduled monuments protected across the UK.
Hetty Pit is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is GM459.
Several scheduled monuments lie within 10 km, including Pen-y-Coedcae Roman Camp (3.1 km), Newbridge Beam Engine (3.7 km), Tarren Deusant Sculptured Rock & Spring (3.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Hetty Pit's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Hetty Pit stands on South Wales Upper Coal Measures Formation, bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.