Wheal Friendship

Overview

Wheal Friendship, at Mary Tavy on the western edge of Dartmoor, was one of Devon's largest copper mines and, later, one of Britain's principal sources of arsenic — a 130-year working life that shaped the village around it and launched the career of one of Britain's most influential mining engineers, John Taylor.

History

Wheal Friendship was worked for around 130 years from the late 18th century, extending underground from beneath Mary Tavy's own village street east to the Tavy valley and nearly a mile westward beyond it — second only to Devon Great Consols in scale among the district's copper mines. John Taylor took over the mine's management in 1798, still in his twenties, and it was here that he made his name before going on to manage mines across Britain, including Magpie Mine in Derbyshire, Greenside Mine in Cumbria and Coniston Copper Mines; he sank a further new shaft in 1826 and drove an extensive system of leats to power the site with water rather than coal. Copper mining was highly profitable from the late 18th century until around 1870, by which point the mine had produced an estimated 145,805 tons of copper ore, alongside 1,170 tons of lead, 120 tons of tin and 4,343 tons of arsenic. As copper profits fell through the 1870s, the mine's owners shifted its focus decisively to arsenic, then in high demand as an insecticide and pigment: enormous condensing chambers and flues were built, new shafts sunk, and an incline tramway laid to serve the new arsenic works. The mine's main underground working had ended by 1901, though tribute working of dumps and tailings continued on a reduced scale into the 1950s; primary operations are recorded as having formally ceased in July 1925 amid a slump in the arsenic market.

Geology

The mine worked copper, tin and arsenic-bearing lodes associated with the Dartmoor granite, part of the same Cornubian orefield responsible for the mineralisation at nearby Devon Great Consols and Hemerdon.

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

Workings

Water power was central to the mine's operation from the start: over some 40 years John Taylor and his successors brought water in via two long leats from the River Tavy, eventually running 17 leats and waterwheels across the site. A 40-foot waterwheel powered what is described as the world's first railway incline shaft, sunk to the 112-fathom level in 1808, followed by a second incline down to the 200-fathom level in 1826-27. From the 1870s the mine was transformed again by the arsenic works: large calciners roasted the ore, and condensing chambers and flues, connected by an incline tramway, captured the arsenic for processing.

Closure

Primary underground working is recorded as having ended in July 1925 amid a collapse in the arsenic market, though the BGS's own abandonment-plan catalogue records the mine as abandoned in 1901; the working of surface dumps and tailings continued on a much smaller scale into the 1950s.

What remains

Substantial remains survive across the site, including arsenic condensing chambers and flues, three tin-working buddles, the ruins of a 1912 mill, Bennett's and Brenton's shafts, wheelpits, remnants of flat-rod systems that transmitted power from the waterwheels, miners' dry buildings, and the leats and reservoirs that once fed them — much of it accessible via public footpaths around Mary Tavy.

Leats, reservoirs and the calciner ruins of the arsenic works are the most visible surviving features, spread across a wide area either side of the Tavy valley.

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.

• By 1865 the mine had produced an estimated 145,805 tons of copper ore, 1,170 tons of lead, 120 tons of tin and 4,343 tons of arsenic. ¹
• Primary operations ceased in July 1925 amid a slump in the arsenic market, though tribute working of dumps and tailings continued into the 1950s; the BGS abandonment-plan catalogue separately records the mine as abandoned in 1901. ^1,2

Images

Sources

1. (secondary) Wheal Friendship (1870s to 1950s) — Dartmoor Explorations
2. (primary) Wheal Friendship Mine Plan (BGS Mine Plans Catalogue, OMR115) — British Geological Survey / The Coal Authority
3. (secondary) Wheal Friendship - The mine that made John Taylor — navsbooks

Record created: 22 August 2026 · Last researched: 22 August 2026