Glyntillery Colliery was located near to Hafodyrynys between Pontypool and Crumlin. Work commenced on site with the driving of two levels in 1910 which by 1928 saw were 52 miners producing coal here. In 1938 the workforce had increased to 129 and by the time Nationalisation came in January 1947, the staff and workers had increased to 135 men underground while 20 men worked on the surface. The output at that time was around 1400 tons per week.

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In the 1950s Hafodyrynys was to have huge investments injected into its mining industry, which came in the form of a new mine that was constructed to handle the output of coal from several mines that included Glyntillery, Hafodyrynys old mine, Tirpentwys, and Blaensychan. The original Hafodyrynys Colliery closed in 1966 while Tirpentwys ceasing work in 1969, this left only Glyntillery mine in production until it finally closed in December of 1975.