During the 1880s, David Davies of Llandinam (Davies the Ocean) arrived in the village of Ynysybwl, convinced there were large deposits of deep coal to be mined. Tests at ‘Graigddu' (Black Rock) proved positive and the first sod was cut on 16 June 1884. By September of that year, 200 men had been employed to work in the new colliery, many of them from David Davies' hometown of Llandinam.
Two years after the first sod was cut the Lady Windsor Colliery was producing large quantities of first-class coking coal; a luxury hotel ‘The Windsor Hotel' had already been completed; and work had commenced on 300 cottages for miners. New roads and a railway station followed and in a very short time, Ynysybwl became a hive of industrial activity.
Miners’ wages were low. In 1886 colliers earned between 3s 6d and 5s 0d a week poverty and hunger was rife, yet the shareholders of Lady Windsor were taking a massive 50% dividend. Grand managers houses were built, Tynywern – 1888 and Glynderwen – 1904.
Conditions underground remained poor with oil lamps still in use after the 1921 strike. It wasn't until 1930 that the colliery owners began to consider the working conditions and welfare of the miners who worked for them, and in 1931, the Lady Windsor was among the first collieries in Wales to provide a pithead baths and first aid/medical treatment room. Residents of the village were also allowed to use the baths for a small fee (3d to 6d).
Nationalisation took place on 1 January 1947 and by the 1950s more people were being employed at the nearby ‘Treforest Trading Estate' resulting in a shortage of manpower at many collieries in South Wales. Displaced and stateless Europeans were offered work in the pits with special allowances, but even this did not fulfil the labour needs of the mines. By 1956 The Lady Windsor was in need of deeper exploitation with almost all the reserves in the Upper Seams being exhausted.
Miners’ traditional unity was put to the test as smaller mines were closed throughout the country and their miners offered work in Ynysybwl. Mobile homes at Buarth-y-Capel were built for the miners and their families and on 10 April 1964 many from County Durham arrived at Ynysybwl.
A strike in 1972 stopped production for 2 months, but in 1973 the National Coal Board (NCB) launched a ‘Plan for Coal' with over £100,000,000 being set-aside for South Wales alone. In 1974 the Lady Windsor was linked to Abercynon Colliery by two underground parallel tunnels – one 1,000 metres and the other almost a mile. This link-up led to the NCB stating in 1977 that the Lady Windsor/Abercynon Colliery was the least likely colliery to close in Wales. However, following a twelve-month strike in 1984, the Lady Windsor/Abercynon Colliery closed in 1988 with over 25 years of workable coal left.