Qualla: Dinorwic Quarry

Dinorwic Quarry: Introduction

Mon, 25 May 2026 00:00:00 GMT

Photo credit Gwernol, Public domain. From the air it looks like someone cut a city out of a mountain. Twenty terraced galleries climb each of the two main pits, stepping up in flights so regular they could be staircases for giants. Some are flooded. Some are roofed by collapsed slate. The walls are not grey but bruise-purple, banded with the slick blue-black where rain has run for fifty-seven years since the last shift went home. Dinorwic Quarry covered 700 acres at its peak in the early twentieth century, the second-largest slate quarry in the world, and the second-largest only because Penrhyn down the road was bigger. Three thousand men worked here. Then in July 1969 the company locked the gates. Then it got stranger.

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Image: Gwernol | Public domain

Dinorwic Quarry: The Vein and the Smiths

Mon, 25 May 2026 00:00:00 GMT

Photo credit Paul Glover, CC BY-SA 2.0. The slate vein at Dinorwic runs nearly vertically, lying at or just below the mountain's surface - which is why the quarry could be worked as a series of open stepped galleries rather than as a deep mine. The first commercial extraction began in 1787 when a private partnership to...

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Image: Paul Glover | CC BY-SA 2.0

Dinorwic Quarry: Padarn and the Hunslets

Mon, 25 May 2026 00:00:00 GMT

Photo credit Eric Jones, CC BY-SA 2.0. Slate is heavy. Moving it required engineering. The Padarn Railway ran four-foot gauge from the quarry's main yard at Gilfach-ddu to Port Dinorwic, carrying transporter wagons loaded with narrower two-foot trucks of slate. Inside the quarry itself, a web of internal tramways clim...

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Image: Eric Jones | CC BY-SA 2.0

Dinorwic Quarry: Locking Up in 1969

Mon, 25 May 2026 00:00:00 GMT

Photo credit Eric Jones, CC BY-SA 2.0. The quarry closed in July 1969. Slate had been losing ground for half a century - to ceramic roofing tiles, to corrugated metal, to imports from Spain and China. The Penrhyn quarry next door closed for similar reasons. But Dinorwic did not vanish; it changed jobs. The mountain th...

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Image: Eric Jones | CC BY-SA 2.0

Dinorwic Quarry: Cantilevers, Climbers, and Dragons

Mon, 25 May 2026 00:00:00 GMT

Photo credit CC BY-SA 3.0. The old workshops at Gilfach Ddu became the National Slate Museum, leased from the county council to the National Museum of Wales. Equipment from the internal railway was relaid as the Llanberis Lake Railway, carrying tourists along the trackbed of the old Padarn line. The quarry...

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Image: CC BY-SA 3.0

Dinorwic Quarry: The Rockfall Problem

Mon, 25 May 2026 00:00:00 GMT

Photo credit Eric Jones, CC BY-SA 2.0. Slate weathers. After fifty years of frost and rain, the Vivian quarry suffered major rockfalls in 2020 and again in 2022; foot access has been permanently closed there. In spring 2025 a wave of TikTok videos brought a surge of visitors who did not always know the difference betw...

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Image: Eric Jones | CC BY-SA 2.0