Copper Hill Mine

Overview

A Gwennap copper mine absorbed into the wider United Mines group, in a district once described as 'the richest square mile on earth' for its 18th- and early-19th-century copper output, before closing around 1870 as part of Clifford Amalgamated Mines.

History

Copper Hill Mine was eventually incorporated into the expanded United Mines group, alongside Wheal Britannia, Wheal Clifford, Wheal Moor and Wheal Squire -- itself founded around 1780 from the amalgamation of Ale and Cakes Mine, Wheal Cupboard and Poldory. Gwennap was, in the 18th and early 19th centuries, the richest copper-producing district in Cornwall and arguably the world, contemporaries calling it 'the richest square mile on earth'. In the early 1820s the mining engineer John Taylor acquired the lease of the largely abandoned United Mines workings and rebuilt them into profitability, striking what was at the time the richest copper lode in the world; the mines were well in profit by 1822. At its 19th-century peak the United Mines group's underground workings extended some 80 miles, driven by 22 operating engines; between 1815 and 1861 the group as a whole raised 347,500 tons of 7.5%-grade copper ore, alongside 250 tons of black tin, 158 tons of arsenic, 1,290 tons of pyrite and 271 tons of zinc ore. United Mines merged with the neighbouring Consolidated Mines in 1857 to form Clifford Amalgamated Mines, which continued operating, increasingly unprofitably, until closure around 1870 as metals discovered elsewhere in the world depressed global prices.

Geology

Copper in the Gwennap lodes of the United Mines ground, where the group raised 347,500 tons of ore averaging 7.5 per cent copper between 1815 and 1861.

Workings

One of the mines absorbed into the wider United Mines group, whose combined 19th-century workings extended some 80 miles underground and were served by 22 operating engines.

Closure

Closed around 1870 as part of Clifford Amalgamated Mines, following declining global metal prices.

What remains

Unknown.

Related mines

• United Mines — Absorbed into the wider United Mines group in the 19th century.

Recorded claims

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

• Copper Hill Mine was eventually incorporated into the expanded United Mines group, alongside Wheal Britannia, Wheal Clifford, Wheal Moor and Wheal Squire. ¹
• Gwennap was, in the 18th and early 19th centuries, the richest copper-producing district in Cornwall and arguably the world, contemporaries calling it 'the richest square mile on earth'. ¹
• In the early 1820s John Taylor rebuilt the largely abandoned United Mines workings into profitability; between 1815 and 1861 the group raised 347,500 tons of 7.5%-grade copper ore alongside black tin, arsenic, pyrite and zinc ore, before merging into Clifford Amalgamated Mines in 1857 and closing around 1870. ²

Photographs & further reading

Sources

1. (secondary) United Mines, Gwennap Cornwall — Cornwall Calling
2. (secondary) United Mines — Grace's Guide to British Industrial History

Record created: 30 August 2026 · Last researched: 31 August 2026