Clogwyn Coch Copper Mine

Overview

A high copper mine on the crags above Llyn Du'r Arddu, halfway up Snowdon, worked from the late eighteenth century into the 1860s, usually in tandem with the Llanberis mine in the valley below.

History

Clogwyn Coch, 'the red rock', is a copper mine on the crags above Llyn Du'r Arddu, about halfway up Snowdon at the head of Cwm Brwynog. It appears to have begun towards the end of the eighteenth century; Samuel Lewis, writing in the 1840s, called it comparatively recent and worked only for a few years. It usually ran in conjunction with the Llanberis mine two miles to the north, the miners working at the upper site in summer and the lower one in winter, though at times it worked all year, when extra blankets were issued in the barracks.

In 1830 five levels were in work, and in January 1831 Rowland Philips was fined 2s 6d for breaking a wagon on the incline, whose remains still stand out on the site. The mine was at work in the 1850s and 1860s, and in 1873, after a favourable report by Nicholas Ennor, Edmund Spargo attempted a reopening. Robert Hunt's statistics record 191 tons of ore returned in 1822, 1829, 1830, 1838, 1839 and 1867, only part of the true output, much of which went elsewhere or was counted with Llanberis. A persistent rumour that the workings connect underground with the Britannia mine is unlikely.

Geology

Copper ore in a quartz matrix in the volcanic rocks of Snowdon.

Workings

Several levels (five at work in 1830) in precarious workings on the crags above the lake, with trial mines and an incline down to the ore-processing buildings.

Closure

Last recorded ore return in 1867; an attempted reopening by Edmund Spargo followed in 1873.

What remains

The adits, miners' cottages, trial mines and the incline remain; the workings on the crags are precarious.

Adits, ruined miners' cottages or barracks, trial workings, and an incline leading down to ore-processing buildings near the lake.

Redevelopment

Open mountain land within Eryri National Park.

Related mines

• Britannia Copper Mine — Neighbouring Snowdon copper mines, rumoured (unlikely) to connect underground.
• Llanberis Copper Mine — Worked together: miners spent summer at Clogwyn Coch and winter at Llanberis.

Recorded claims

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

• Clogwyn Coch appears to have begun towards the end of the eighteenth century. ^1,2
• Clogwyn Coch usually worked in conjunction with the Llanberis mine, its miners at the upper site in summer and the lower in winter. ¹
• In 1830 five levels were active at Clogwyn Coch. ¹
• Robert Hunt's statistics record 191 tons of ore from Clogwyn Coch in 1822, 1829, 1830, 1838, 1839 and 1867. ^1,2
• In 1873, after a favourable report by Nicholas Ennor, Edmund Spargo attempted to reopen the mine. ¹
• In the 1840s the Clogwyn Coch mine was described as comparatively recent and worked only for a few years. ³

Sources

1. (secondary) Clogwyn Coch, Copper Mine (NPRN 33768) — Coflein (RCAHMW)
2. (secondary) Clogwyn Coch (Buddlepit Mine Database) — Buddlepit Mine Database
3. (primary) A Topographical Dictionary of Wales (Samuel Lewis, 1849): Llanberis — British History Online

Record created: 19 October 2026 · Last researched: 19 October 2026