Cwmystwyth Mines

Overview

Cwmystwyth is one of the most important metal-mining sites in Wales, worked on and off for around 4,000 years — from Bronze Age copper working through Roman-era lead extraction to a 19th-century peak in lead, silver and zinc, before finally closing in 1950. It's a Scheduled Ancient Monument, and still an active source of metal contamination in the River Ystwyth today.

History

The earliest mining at Cwmystwyth dates to the Early Bronze Age, when copper was worked from the Comet lode in an opencast on Copa Hill — among the oldest known metal mines in Britain. In 2002 excavation nearby uncovered the Banc Ty'nddôl sun-disc, a gold artefact over 4,000 years old and the earliest piece of gold metalwork yet found in Wales. Lead has been worked here since at least Roman times, and the site probably came under the control of Strata Florida Abbey during the medieval period, when it lay within the abbey's Cwmystwyth grange. Silver, lead and zinc mining peaked in the 18th century, with water extensively used for hushing, prospecting and ore processing via leats carried along the valley contours from upstream. Activity increased further from 1750, reaching its most productive period in the mid-19th century, before declining through the late 19th and early 20th centuries as ore reserves depleted and cheaper foreign competition undercut prices. The mine was worked intermittently, at varying profitability, until final abandonment in 1950.

Geology

The site exploits lead-, silver- and zinc-bearing veins alongside earlier Bronze Age copper workings, within the Cambrian Mountains of mid Wales.

Workings

Working methods spanned four millennia, from Bronze Age opencast working of surface lodes to sophisticated 18th- and 19th-century operations using water-powered machinery fed by contour leats for pumping, ore crushing and processing.

Closure

The mine closed for the final time in 1950 after a long decline driven by depleted ore reserves, rising production costs and foreign competition.

What remains

The site continues to discharge significant quantities of metal contamination into the River Ystwyth: Natural Resources Wales estimates around 12 tonnes of zinc, 2 tonnes of lead and 30 kg of cadmium enter the river from the site each year, causing it to fail Water Framework Directive standards, with elevated zinc detectable as far away as Cardigan Bay. Water quality has nonetheless improved substantially since mining ended: surveys found only 9 aquatic species and lead at 0.4 mg/L in 1919, rising to 63 species and lead below 0.05 mg/L by 1939, with fish returning to most of the river by 1975 — though a roughly 3 km stretch immediately below the mine remained fish-free at that point.

Extensive surface remains survive across the site, reflecting nearly four millennia of activity, and it is designated a Scheduled Ancient Monument within the Upland Ceredigion Landscape of Historic Interest.

Redevelopment

Natural Resources Wales has proposed a phased remediation programme: watercourse and surface-water management and erosion control on spoil heaps first, followed by a period of monitoring to inform the design of a mine-water treatment system as a longer-term measure.

Abandoned workings can be dangerous — unstable ground, uncapped shafts, flooding and bad air are common even where a site looks safe from the surface. This entry describes history and general location only; it is not an access guide.

Recorded claims

Individual factual claims, each attached to the source(s) that support it. Where sources disagree, both are kept.

• In 2002, excavation near the mine uncovered the Banc Ty'nddôl sun-disc, a gold artefact over 4,000 years old and the earliest piece of gold metalwork yet found in Wales. — Cwmystwyth Mines
• The site is estimated to discharge around 12 tonnes of zinc, 2 tonnes of lead and 30 kg of cadmium into the River Ystwyth annually, causing the river to fail Water Framework Directive standards. — Cwmystwyth Lead Mine
• Average miner lifespan at Cwmystwyth has been estimated at just 32 years, attributed to acute lead poisoning from the ore being worked. (uncertain) — Cwmystwyth Mines

Photographs & further reading

This page doesn't try to reproduce everything — these are the best original sources found for this mine.

Images

Sources

1. (primary) Cwmystwyth Lead Mine — Natural Resources Wales
2. (secondary) Cwmystwyth History — Ceredigion Historical Society
3. (secondary) Cwmystwyth Mines — Wikipedia