Wheal Maid

Overview

Wheal Maid, in the heart of the Gwennap mining district, was a highly profitable Georgian copper mine in its own right before a very different kind of afterlife made it notorious a century later — as the tailings dam that turned its valley into one of Cornwall's most visibly contaminated post-mining landscapes.

History

Wheal Maid worked from 1782 into the 1870s, extracting copper as its main product alongside tin and arsenic, and was highly profitable in its earlier decades: between 1800 and 1840 the mine is reported to have returned up to £200,000 in profit to its adventurers. The mine merged with neighbouring workings in 1852 to form St Day United. Wheal Maid's modern notoriety, however, dates from a century after its own closure: through the 1970s and 1980s its former valley was turned into a series of large lagoons used to store fine-grained tailings waste from two nearby active mines, Mount Wellington and Wheal Jane, with control passing to Carnon Consolidated Tin Mines after Mount Wellington's 1981 closure. An Environment Agency investigation completed in 2007 found high levels of arsenic, copper and zinc contamination in the surrounding soil, and by 2012 parts of the site were formally assessed as too hazardous for casual human activity. Gwennap Parish Council bought the site for £1 in 2002.

Geology

The mine originally worked copper lodes of the Gwennap mining district, part of the granite-related hydrothermal mineralisation of central Cornwall; the tailings later deposited across the site are dominated by pyrite-bearing material that has continued to oxidise since deposition, generating acidic, metal-laden drainage.

Geological setting: Hydrothermal Deposits (well documented example), Veins and Lodes (well documented example)

Closure

The mine itself closed in the 1870s after merging into St Day United in 1852; its valley was later repurposed as a tailings dam for two other mines through the 1970s and 1980s.

What remains

The site remains one of Cornwall's most visibly contaminated post-mining landscapes, its tailings lagoons taking on striking mineral-stained colours in dry weather; it is formally designated Contaminated Land under the Environmental Protection Act 1990, though it is also now popular with walkers, mountain bikers and horse riders.

19th-century mining remains survive around the valley alongside the later tailings lagoons, whose distinctive orange, ochre and grey colouring comes directly from the arsenic, copper and iron sulphide minerals within the stored waste.

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.

• Between 1800 and 1840 the mine is reported to have returned up to £200,000 in profit to its adventurers. ¹
• An Environment Agency investigation completed in 2007 found high levels of arsenic, copper and zinc contamination in the surrounding soil; the site is formally designated Contaminated Land under the Environmental Protection Act 1990. ^1,2

Sources

1. (secondary) Wheal Maid — Wikipedia
2. (secondary) Evolution of Sulfidic Legacy Mine Tailings: A Review of the Wheal Maid Site, UK — Minerals (MDPI), peer-reviewed journal
3. (primary) CARNON CONSOLIDATED TIN MINES LTD WHEAL JANE WHEAL MAID TAILINGS DAM mine plan — British Geological Survey

Record created: 23 August 2026 · Last researched: 23 August 2026