Parc Mine

Overview

Parc, in the Gwydir Forest near Llanrwst, was the largest and longest-lived of the area's lead and zinc mines — worked on and off for over a century and, by the time it finally closed in 1963, the last mine still operating in the forest.

History

The mine began in 1855 as the Gwydyr Park Consols, an amalgamation of older workings, and was worked intermittently up to the 1940s. It reopened in 1950 and, between 1953 and 1957 alone, produced more lead and zinc ore than the whole of the wider Llanrwst mining area had between 1848 and 1939. Underground, its principal lode had been driven far enough to connect with the older Llanrwst and Cyffty mines, though neither offered any substantial remaining ore. Parc closed for good in 1963, having recovered more than 10,000 tons of lead and 4,000 tons of zinc over its working life, and was interconnected underground with eleven other mines in the district. The mine is also recorded under other names — Gwydyr Park Consols at its formation, and De Eresby or D’Eresby Mountain Lead Mine — and the Royal Commission’s record has official output beginning in 1860 under the D’Ersby and Gwydyr Company, with evidence of much earlier working of the lodes than that.

Geology

Parc worked a series of vein systems in the Ordovician rocks of the Gwydyr Forest, cut by mineralising fluids that rose through the cracks and faults long after the rocks themselves had formed. Three structures mattered. The Gors Vein, running north–south, is an unusually robust lode for the district at between 12 and 30 feet wide, filled with granular quartz carrying galena and sphalerite; the ore shoot worked from the Gors Shaft is reputed to have yielded 16,000 tons of lead concentrates by itself. The Fucheslas Lode is the other of the two north–south veins on which the older workings were begun. The Parc or Principal Lode, which takes a north-easterly strike within the mine and was the twentieth century’s main concern, is filled not with a simple vein but with breccia — fragments of the shattered host rock cemented by quartz — again carrying sphalerite and galena. The eastern limit of the workings is set by the Shale Vein, a substantial fault zone striking north-north-west and made mostly of pulverised black shale, with scattered pockets and lenses of quartz and calcite carrying sphalerite.

Geological setting: Faults and Fractures (well documented example), Veins and Lodes (well documented example)

Workings

The mine was formed by amalgamating older workings on the north–south Gors and Fucheslas lodes, and in the twentieth century turned to stoping the east–west Principal Lode from Nos. 2 and 3 levels, following it for about two miles until the workings passed beneath the older Llanrwst and Cyffty mines. No. 3 adit, driven south along the Gors Lode, was the main haulage level of the modern mine; the smaller arched brick No. 4 adit lies just below it. South of the adits is Kneebone Cuttings, a large open stope, and the flooded Gors Shaft. About 500 ft along No. 3 a fork leads to later workings on the Hafna Lode. Further in, the underground Parc Shaft — a large bore, about ten metres square — was driven 220 ft below No. 3 level, with a circular passage round it, a gantry above in an intermediate level and a flooded incline down to No. 4 nearby. West of the shaft the Principal Lode runs on as an access passage in the footwall of the stope, with stopes 150 ft high and ore chutes at intervals, until a major collapse terminates the level and holds a great weight of water behind it. No. 2 level, one of the older workings on the Fucheslas Lode, reaches the Principal Lode at a junction above a deep stope floored only by a dangerous false floor. A choke dam a short way up No. 3 adit exists to prevent a catastrophic release should that Principal Lode choke give way.

Closure

Parc closed for good in 1963, having outlasted every other mine in the Gwydyr Forest. Its last phase was its most productive: between 1953 and 1957 alone it raised more lead and zinc ore than the whole Llanrwst area had between 1848 and 1939. Official records of output begin in 1860, under the D’Ersby and Gwydyr Company, though there is evidence of much earlier working of the lodes.

What remains

After closure, a large spoil tip below the Level 3 adit caused ongoing problems: flash flooding eroded the tip and washed metal-rich sediment onto farmland more than a kilometre downstream, prompting a reclamation scheme in 1977 that stabilised the tip and built a new lined channel for the Nant Gwydyr stream. The Level 3 adit entrance collapsed in 2011, redirecting drainage through the Level 4 adit via a natural void known as Kneebones Cutting. The site holds Site of Special Scientific Interest and Special Area of Conservation status, and Natural Resources Wales and the Mining Remediation Authority are developing a further remediation scheme for the site under the Wales Metal Mines Programme, with construction anticipated from 2026.

The gated No. 3 adit is the prominent feature, discharging ochreous water at the head of the landscaped tailings; the smaller brick-arched No. 4 adit is just below it and blocked a short way in. The Gors Shaft nearby is flooded. Older workings on the site are flooded or lost, and the more recent adits have been gated.

What's uncertain

Points where sources disagree or the record could not be settled; both accounts are kept. All open questions in the archive.

• A 2017 report describes numerous ore chutes and dangerous false floors in the upper levels, with some collapsed sections dropping 70 feet or more, and notes that Level 2 was used for scientific pendulum experiments studying coastal deformation in 1968 before being sealed. (uncertain) ²
• The mine was formed by amalgamating older workings on the north–south Gors and Fucheslas lodes; the Gors Vein is 12 to 30 feet wide and filled with granular quartz carrying galena and sphalerite, and the ore shoot worked from the Gors Shaft is reputed to have yielded 16,000 tons of lead concentrates alone. (uncertain) ⁴

Recorded claims

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

• Parc recovered more than 10,000 tons of lead and 4,000 tons of zinc over its working life, and was interconnected underground with eleven other mines in the Gwydir Forest district. ¹
• A large spoil tip below the Level 3 adit caused repeated pollution incidents after closure, with flash floods washing metal-rich sediment onto farmland more than a kilometre downstream, until a 1977 reclamation scheme stabilised the tip and built a new lined channel for the Nant Gwydyr stream. ¹
• The Level 3 adit entrance collapsed in 2011, redirecting the mine's drainage through the Level 4 adit via a natural void known as Kneebones Cutting. ¹
• A 2017 report describes numerous ore chutes and dangerous false floors in the upper levels, with some collapsed sections dropping 70 feet or more, and notes that Level 2 was used for scientific pendulum experiments studying coastal deformation in 1968 before being sealed. (uncertain) ²
• Parc is also recorded as Gwydyr Park Consols and as De Eresby or D’Eresby Mountain Lead Mine. Official records of its first output date from 1860, when it was operated by the D’Ersby and Gwydyr Company, though there is evidence of much earlier exploitation of the lodes. ^3,4
• The mine was formed by amalgamating older workings on the north–south Gors and Fucheslas lodes; the Gors Vein is 12 to 30 feet wide and filled with granular quartz carrying galena and sphalerite, and the ore shoot worked from the Gors Shaft is reputed to have yielded 16,000 tons of lead concentrates alone. (uncertain) ⁴
• Twentieth-century working concentrated on stoping the east–west Principal Lode from Nos. 2 and 3 levels for about two miles, passing beneath the older Llanrwst and Cyffty workings; within the mine the Parc or Principal Vein strikes north-east and is filled with a breccia of fragmented host rock cemented by quartz, carrying sphalerite and galena. ⁴
• Natural Resources Wales records Parc as sitting in close proximity to numerous other independent mines such as Hafna and Pandora, and as interconnected through its underground workings with eleven other mines — without identifying which. ¹

Photographs & further reading

Sources

1. (primary) Parc Mine — Natural Resources Wales
2. (observational) Parc Lead Mine, North Wales — September 2017 — 28DaysLater
3. (primary) Parc Lead Mine (NPRN 411616) — Royal Commission on the Ancient and Historical Monuments of Wales
4. (observational) Parc Mine — Buddlepit mine database — Buddlepit
5. (primary) Mine plan search: PARC MINE LLANRWST — BGS / Mining Remediation Authority mine plans catalogue
6. (secondary) Introduction to the lead mines of the Gwydyr Forest — cowdery.org.uk
7. (secondary) Mines of the Gwydyr Forest: Part 3. Parc Mine, Llanrwst and Adjacent Setts. — ResearchGate (academic)
8. (secondary) Parc Mine, Trefriw, Conwy, Wales, UK — Mindat

Record created: 20 August 2026 · Last researched: 6 September 2026