Wheal Harmony

Overview

A copper, tin and wolfram mine on the northern edge of Redruth, Cornwall, worked on the eastern extension of the Wheal Tolgus main lode. Mining on the site is documented from at least the 1760s under the name Treleigh Wood Mine; the workings were consolidated as Wheal Garden around 1816-17 and renamed Wheal Harmony on obtaining a new lease, working jointly with the adjoining Wheal Montague as "Montague and Harmony" from 1819 until the early 1840s. The southern part of the site reopened under the old name, Treleigh Wood Mine, from 1872 to 1879. A 2013-14 archaeological watching brief ahead of housing redevelopment recorded mine shafts, lode-working trenches and the standing remains of a late-19th-century engine house, which were preserved in situ within the new development.

History

Documentary evidence places mining on the site from at least the 1760s, recorded under the name Treleigh Wood Mine. The workings had gone out of use by the early 19th century. Around 1816-17 the site was consolidated as Wheal Garden through the amalgamation of Treleigh Wood Mine with several smaller neighbouring workings — Wheal Diamond, the Wheal Butler copper mine and Wheal Gilbert — initially worked with water-driven engines with little depth. Plans were then made to introduce steam engines and drive a deep adit to reach lodes the shallower workings had not touched. On taking a new lease the mine was renamed Wheal Harmony. Per the mining historian H.G. Dines, Wheal Harmony worked the eastern extension of the Wheal Tolgus main lode — the same lode system worked by the much larger East Pool, Tolgus United and South Crofty group of mines immediately to the west — and there are indications the workings followed this lode for around 600 yards to the east, though no mine plan confirming this extent is known to survive. From 1819 the mine was worked jointly with the neighbouring Wheal Montague as "Montague and Harmony", raising copper, tin and wolfram, until the partnership ran into difficulty by the early 1840s; the site was given over to agriculture and enclosed with Cornish hedges shortly afterwards, probably in the early 1840s. A Mining Remediation Authority abandonment plan covering the combined workings under the title "Treleigh Consols New Wheal Harmony Wheal Maria" carries an abandonment date of 1864, which would place at least some further activity or amalgamation on the site in the two decades usually described as its dormant period — the plan's own mineral coding lists it generically as coal-related, evidently a cataloguing default rather than a real record of what was worked, so this should be read as a data point on continued activity rather than a firm operational history. In 1872 the southern part of the site reopened under the original name, Treleigh Wood Mine, and worked until 1879. A mine plan of Wheal Montague and Wheal Harmony dated 1871 shows three shafts — the main engine shaft (named Treleigh Wood Shaft), Windmill Shaft to the south-east and Nutwood Shaft immediately south of the mine buildings — and an accounts house. The standing engine house remains recorded in 2013-14 are considered likely to date from this final phase of working; an 1880 Ordnance Survey map shows three engine houses on the site, a pumping engine beside the main shaft, a winding engine and a stamps engine with dressing floors, the latter two of which lay outside the area later assessed and were probably demolished during 20th-century industrial development to the north.

Geology

The mine lies on the Porthtowan Formation (Devonian metamudstone and metasandstone) with no significant overlying superficial deposits, on the eastern extension of the Wheal Tolgus main lode — part of the same mineralised lode system worked at much greater scale immediately to the west by South Crofty, East Pool and Agar, and the Tolgus United group of mines.

Workings

A 2013-14 watching brief recorded sub-circular shafts up to 5m in diameter and three major east-west lode-working trenches up to 20m wide, worked for tin; investigated depths reached up to 4-5.7m below present ground level without exposing the full depth of any feature. A cluster of smaller, shallower features to the west of the engine house are interpreted as test pits dug to prospect the tin-bearing ground rather than as worked shafts. No dating evidence was recovered from any of the mine features during the watching brief, so individual workings cannot be firmly assigned between the 18th-century and 1819-44 phases.

Closure

The site fell out of use as a working mine after 1879. Cornish hedges recorded across the site correspond to the mid-19th-century field system shown on the 1841 Tithe Map, and overlie earlier lode-working trenches, indicating the site had already reverted to agricultural use once by the early 1840s, before the final 1872-79 phase of working.

What remains

The site was redeveloped for housing and business use (the Wheal Harmony estate/business park, Treleigh, Redruth) following an archaeological watching brief carried out by Cotswold Archaeology between April 2013 and June 2014 ahead of groundworks. Two sections of granite wall belonging to the former engine pumping house, including a slot that once carried a beam to the adjacent engine shaft, were recorded and preserved in situ within the new development, along with a nearby brick-and-granite flue. Two of the spoil mounds shown on the 1841 Tithe Map, in what was recorded as "Burrows Field", remain visible.

Standing sections of granite-built engine house wall (up to 6m long, surviving to over 2.2m high) and an associated brick-vaulted flue, both dating from the 1870s working and retained within the modern development; two 19th-century spoil mounds.

Redevelopment

Housing and business-park development on land formerly occupied by the mine's northern workings, granted planning consent by Cornwall Council (refs PA12/10101, PA12/10102 and PA12/10103); the archaeological watching brief was a condition of that consent.

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.

• Documentary evidence indicates mining on the site, then known as Treleigh Wood Mine, from at least the 1760s; it had gone out of use by the early 19th century. ¹
• Around 1816-17 the site was consolidated as Wheal Garden through the amalgamation of Treleigh Wood Mine with the smaller Wheal Diamond, Wheal Butler and Wheal Gilbert workings; on taking a new lease to sink deeper and introduce steam engines, the mine was renamed Wheal Harmony. ²
• According to the mining historian H.G. Dines, Wheal Harmony worked the eastern extension of the Wheal Tolgus main lode, with indications the workings followed it for around 600 yards to the east — though no surviving mine plan confirms the full extent, as no plan of that detail is known to survive. (high) ²
• From 1819 the mine was worked jointly with the neighbouring Wheal Montague as "Montague and Harmony", raising copper, tin and wolfram, until the enterprise ran into difficulty by the early 1840s. ¹
• A Mining Remediation Authority abandonment plan for the combined workings, titled 'Treleigh Consols New Wheal Harmony Wheal Maria', carries an abandonment date of 1864 — a data point suggesting some further activity or amalgamation during the period most secondary accounts describe simply as dormant between the 1844 closure and the 1872 reopening, though the plan's own record gives no further operational detail. (uncertain) ³
• In 1872 the southern part of the site reopened under the original name, Treleigh Wood Mine, and remained in operation until 1879. The standing engine house remains recorded in 2013-14 are considered likely to date from this final phase. ¹
• A mine plan of Wheal Montague and Wheal Harmony dated 1871 shows three shafts: the main engine shaft (Treleigh Wood Shaft), Windmill Shaft to the south-east, and Nutwood Shaft immediately south of the mine buildings, plus an accounts house. ¹
• A Cotswold Archaeology watching brief ahead of housing redevelopment recorded sub-circular mine shafts up to 5m in diameter and three major east-west lode-working trenches up to 20m wide, used for tin extraction, along with standing granite engine-house walls and a brick-vaulted flue from the 1870s working. No dating evidence was recovered from any mining feature, so individual workings could not be assigned with confidence to a specific phase. ¹

Photographs & further reading

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

Sources

1. (primary) Wheal Harmony, Redruth, Cornwall: Archaeological Watching Brief — Cotswold Archaeology (CA Report 14432)
2. (secondary) Harmony, Wheal — mine record — Buddlepit Mine Database (Mining History Trust)
3. (primary) Treleigh Consols New Wheal Harmony Wheal Maria — Mine Remediation Authority abandonment plan (OMR124A) — British Geological Survey / Mining Remediation Authority mine plans catalogue

Record created: 29 August 2026 · Last researched: 29 August 2026