# Delabole Slate

> Roofing slate from the Delabole quarry in north Cornwall, worked continuously since the 15th century and one of England's largest slate quarries.

- URL: https://roof.wiki/delabole-slate/
- Topic: Roofing Materials
- Also known as: Cornish slate; Old Delabole Slate Quarry
- Regions: Europe
- First published: 2026-11-02 · Last reviewed: 2026-11-02
- Cite as: "Delabole Slate." roof.wiki. https://roof.wiki/delabole-slate/

## Key facts

- **Location:** Delabole, north Cornwall, England
- **Worked since:** 15th century (continuously)
- **Quarries combined:** 1841
- **Workforce:** About 500 (1910); no more than 40 (2007)

Delabole slate is natural slate from the quarry at Delabole in north Cornwall, England. The quarry has been worked continuously since the 15th century, and it is described as the oldest working slate quarry in England, and slate was reputedly dug there as early as the reign of King Stephen in the 12th century. It is one of the largest slate quarries in England and is often described as the largest single quarry in Britain.

## History

Cornish slate quarrying dates from the late medieval period. In the reign of Elizabeth I, five quarries near Delabole were already supplying slate to Brittany and the Netherlands. In 1841 these workings were combined as the Old Delabole Slate Quarry. The pit was at one time described as the deepest man-made hole in the world, a title since lost to large open-cast mines in America and Australia. A narrow-gauge railway, thought to date from before 1834 and worked by steam and later diesel locomotives, moved slate around the site until after 1987.

## Decline and ownership

About 500 people worked at Delabole in 1910. Competition from Welsh slate and later from manufactured tiles cut demand, and by 2007 only five skilled men worked in the pit, with a total workforce of no more than 40. The company was liquidated in 1977 and run under receivership by Rio Tinto Zinc until 1999, when a local management team bought it. In 2005 its majority shareholders bought the whole share capital, returning the quarry to single family ownership for the first time since 1842.

## Use

Delabole slate is the characteristic roofing and cladding stone of much of north Cornwall and is used for repairs to historic Cornish buildings, where matching the local slate is a conservation concern. Many smaller Cornish coastal quarries that once had an export trade are no longer worked because extraction costs are lower at larger British quarries.

## Sources and gaps

Current production volumes and technical test data for Delabole slate: published information is limited.

## Sources

1. Delabole — Wikipedia. https://en.wikipedia.org/wiki/Delabole
2. Slate industry — Wikipedia. https://en.wikipedia.org/wiki/Slate_industry