Penrhyn Quarry

Penrhyn Quarry lies near Bethesda in Gwynedd, north-west Wales. For much of the 19th century it was the largest slate quarry in the world, and it remains the largest in Britain.

Origins

Slate had been dug in the area since at least 1413. The modern quarry was developed in the 1770s by Richard Pennant, later Baron Penrhyn, who took direct control of slate working on his estate in 1782. By 1792 it employed about 500 men and produced about 15,000 tons of slate a year.

Scale

By the end of the 19th century nearly 3,000 quarrymen worked there. The main pit is nearly 1.6 km (1 mile) long and about 370 m (1,200 ft) deep, worked in a series of stepped terraces called galleries. Larger quarries have since been opened in China, Spain and the United States.

The Great Strike

Relations between the Penrhyn family and the workforce were often bitter. A dispute that began on 22 November 1900 became a three-year strike or lock-out, often described as the longest dispute in British industrial history. Workers returned in November 1903 on terms set by Lord Penrhyn. Historians see the dispute as a turning point in the decline of Welsh slate.

Ownership since 1963

• Alfred McAlpine owned the quarry from 1963 to 2007.
• It was bought in 2007 by Kevin Lagan and renamed Welsh Slate Ltd.
• Breedon Group acquired the Lagan Group in 2018.

About 200 people work there today. Part of the disused site hosts a zip-line attraction.

Heritage

Penrhyn forms part of the landscape recognised in 2021 as the Slate Landscape of Northwest Wales World Heritage Site. Its slates remain in demand for conservation work on historic roofs, where matching original material matters.