Wheal Frementor

Overview

A former tin and tungsten mine on the southern part of the Devon Great Consols site, worked latterly for tin until 1930, whose worked-out vertical deposit left an exceptional open void known as a gunnis.

History

Wheal Frementor -- also recorded as Framator -- lay on the southern part of the already-published Devon Great Consols mine near Tavistock, worked within the only part of the Gunnislake granite body that crosses the River Tamar into Devon. It was originally worked as an opencast for tin and tungsten, wolframite being the principal tungsten ore; a rich, near-vertical deposit of tin here was worked out entirely, leaving a striking 'gunnis' -- an open void some 4 metres wide, 70 metres deep and 200 metres long -- with the main working advancing north-westward for about 100 metres from it. After the wider Devon Great Consols site closed in 1903, underground mining resumed at Frementor around 1915 for tin and tungsten; most work across the site had ceased again by 1925, and at Frementor the Mining in Devon database records the wartime working, driven to 20 fathoms, closing in 1919 and a brief reopening between 1925 and 1929; about 12,000 tons of ore was raised in all, with no recorded output. Its lodes, North Lode and South Lode, carry cassiterite and wolfram in veins 5-15 cm wide at surface widening to almost two metres at depth.

Geology

Tin and tungsten — wolframite the principal tungsten ore — in the southern part of the Devon Great Consols ground, worked first as an opencast.

Workings

Originally an opencast working; its main underground development ran north-westward for about 100 metres from the gunnis, a worked-out vertical tin deposit some 4 metres wide, 70 metres deep and 200 metres long.

Closure

Closed in 1919 after the wartime working and reopened briefly between 1925 and 1929, outlasting most of Devon Great Consols' 20th-century revival, whose arsenic production ended in 1930.

What remains

The gunnis survives as a large, fenced void; several winzes have flooded owing to the site's low, river-level position. The site is open to public access, with visitors warned against climbing the fence around the gunnis.

The fenced gunnis void, flooded winzes, and other mine ruins and remnants across the site.

Related mines

• Devon Great Consols — Wheal Frementor lay on the southern part of the Devon Great Consols site and was worked as part of it.
• Wheal Fanny — Neighbouring sections of Devon Great Consols on the Tamar bank, both reopened about 1915.

Recorded claims

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

• Frementor was originally worked as an opencast within the only part of the Gunnislake granite body crossing into Devon; a rich, near-vertical tin deposit was worked out entirely, leaving a gunnis some 4 metres wide, 70 metres deep and 200 metres long, with underground development advancing north-westward about 100 metres from it. ¹
• Underground mining resumed at Frementor around 1915 for tin and tungsten after the wider Devon Great Consols site closed in 1903; most site-wide work ceased again by 1925, but Frementor, worked latterly mainly for tin, continued until final closure in 1930. ²
• Wheal Frementor, otherwise Framator, at SX 419 726 three-quarters of a mile north-north-west of Gunnislake opposite Clitters Wood, has lodes carrying cassiterite and wolfram 5-15 cm wide near surface and up to almost two metres wide at depth, called North Lode and South Lode, adjoining South Fanny Mine to the east. It originated as an openwork, was developed during the First World War to a depth of 20 fathoms, closed in 1919 and reopened briefly between 1925 and 1929; about 12,000 tons of ore was raised in all but there is no recorded output. ³
• Devon Great Consols closed in 1903 and lay idle for about twelve years until, in about 1915, underground mining was resumed at Wheal Fanny for arsenic and at Wheal Frementor for tin and tungsten. ⁴

Sources

1. (secondary) Wheal Frementor (GooseyGoo) — GooseyGoo
2. (secondary) Devon Great Consols — Wikipedia
3. (secondary) Frementor Mine, Devon (Mining in Devon Database, Devon in Focus) — Devon in Focus
4. (secondary) Devon Great Consols Mine (Graces Guide) — Graces Guide

Record created: 31 August 2026 · Last researched: 24 September 2026