Eaglebrook Mine

Overview

A lead, copper and silver mine above the Nant-y-Moch valley, worked under its original name Nant-y-Cagal from before 1708, then relaunched around 1850 as 'Eaglebrook' in a share-promotion scheme dismissed by a contemporary critic as a fraud on investors.

History

Eaglebrook Mine was worked before 1708 by William Waller's Mine Adventurers under its original name, Nant-y-Cagal -- Welsh for 'dirt brook' -- though the Adventurers relinquished their lease in 1722. Around 1850 a company formed by the Francis family took the mine on for promotion, and the metallurgist Robert Mushet, better known for his work on steelmaking in the Forest of Dean, renamed it Eaglebrook and marketed it to investors as 'the Welsh Potosi', describing two adits exposing foot-wide solid lead veins; share prices duly rocketed. The promotion did not go unchallenged: a letter published around 1851, attributed to J.M. Davies, dismissed the new name as a deliberate obscuring of the mine's unglamorous original one, and the claimed riches as nonexistent, reporting that the heap of ore held up as evidence amounted to 'not as much stuff as will fill three wheelbarrows' and that the mine's much-advertised silver content was barely a third of what had been claimed. Genuine, if modest, working continued regardless: by 1854 the mine had a new 40-foot waterwheel and its deep adit had connected with the Western Engine Shaft, and work in the 1870s concentrated on the eastern end of the sett before final closure in 1874 at a depth of 50 fathoms. Output recorded from 1853 onward totalled 598 tons of lead ore and 71 tons of copper ore, most of it raised between 1856 and 1859.

Workings

Worked via at least four shafts, a deep adit connecting to the Western Engine Shaft by 1854, and a 40-foot waterwheel installed the same year; work in the 1870s concentrated on the eastern end of the sett before final closure at 50 fathoms.

Closure

Closed for good in 1874 at a final depth of 50 fathoms.

What remains

The remains of four shafts survive at the site, now within a designated Site of Special Scientific Interest where mineral collecting is no longer permitted.

The remains of four shafts.

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 below. Where sources disagree, both are kept.

• The mine was worked before 1708 by William Waller's Mine Adventurers under its original name, Nant-y-Cagal, before the Adventurers relinquished their lease in 1722. ¹
• Around 1850 the metallurgist Robert Mushet renamed the mine Eaglebrook and promoted it to investors as 'the Welsh Potosi', causing share prices to rocket; a published letter attributed to J.M. Davies around 1851 dismissed the claims as fraudulent, describing the mine's actual ore heap as barely three wheelbarrow-loads and its silver content as far below what had been advertised. ¹
• By 1854 the mine had a new 40-foot waterwheel and its deep adit had connected with the Western Engine Shaft; work in the 1870s concentrated on the eastern end of the sett before final closure in 1874 at a depth of 50 fathoms, with recorded output from 1853 totalling 598 tons of lead ore and 71 tons of copper ore. ^2,1

Photographs & further reading

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

Sources

1. (secondary) Eaglebrook (Buddlepit Mine Database) — Buddlepit Mine Database
2. (secondary) Eaglebrook Mine, Tal-y-bont — Albion Fire & Ice

Record created: 31 August 2026 · Last researched: 31 August 2026