The Penrhyn quarry is a slate quarry located near Bethesda, North Wales. At the end of the nineteenth century it was the world's largest slate quarry; the main pit is nearly long and deep, and it was worked by nearly 3,000 quarrymen. It has since been superseded in size by slate quarries in China, Spain and the USA. Penrhyn is still Britain's largest slate quarry but its workforce is now nearer 200.
The quarry is significant in the history of the British Labour Movement as the site of two prolonged strikes by workers demanding better pay and safer conditions. The first strike lasted eleven months in 1896. The second began on 22 November 1900 and lasted for three years. Known as "The Great Strike of Penrhyn", this was the longest dispute in British industrial history. During the strike, the community was divided between those who laid down their tools and those who crossed the picket line. Many locals wrote "Nid oes bradwr yn y tŷ hwn" or "There is no traitor in this house" in their front windows. William John Parry, one of the founders of the North Wales Quarrymen's Union, and an alderman in Bethesda, organised a co-operative to take over several other local quarries and employ locked-out Penrhyn quarrymen. He eventually included Pantdreiniog, Moel Faban and Tanybwlch quarries in his operation, all on the north side of the town. In the longer term the dispute cast the shadow of unreliability on the North Welsh slate industry, causing orders to drop sharply and thousands of workers to be laid off. In 2003, on the centenary of the strike, the Transport and General Workers' Union unveiled a plaque in memory of those who participated.
Recent history
From 1963 until 2007 the quarry was owned and operated by Alfred McAlpinePLC. In 2007 it was purchased by Kevin Lagan and renamed Welsh Slate Ltd. Kevin Lagan and his son Peter are now directors of Welsh Slate Ltd which also includes the Oakeley quarry in Blaenau Ffestiniog, the Cwt Y Bugail quarry and the Pen Yr Orsedd quarry. The Lagan Group was itself acquired by the Leicestershire-based Breedon Group in 2018. A part of the site no longer in use for slate extraction is the site of a new adventure tourism facility operated by Zipworld. The zip lineVelocity 2 flies above an abandoned flooded quarry. Welsh slate such as that quarried at Penrhyn was designated by the International Union of Geological Sciences as a 'Global Heritage Stone Resource' early in 2019 in recognition of its significant contribution to world architectural heritage.