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. Historically, most accounts of the strike have mainly looked at its effects on male workers, owners, management, economy, and trade unions. However, modern historians are working to broaden this focus. They aim to shed light on the wider community's experiences during the strike, paying special attention to the often ignored roles and perspectives of women. In the longer term the strike lessened confidence in the Welsh slate industry, leading to declining orders and greater unemployment. 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 ==