The Tankersley ironstone bed was named from its outcrop at Tankersley near Barnsley in South Yorkshire. The ironstone occurs in the Coal Measures as nodules[a]Small rounded lumps of matter distinct from its surroundings and thin seams of siderite[b]A brown mineral consisting of ferrous carbonate, the main component of some kinds of ironstone in mudstone about 5 to 15 metres above the Flockton Thick coal.
Ironstone was mined from bell pits in Tankersley before 1795. Tankersley Park was exploited for deposits of iron ore in the early and middle 19th century. At the 1851 census two deep pits and several gin pits employed 251 miners in the parish. Three shafts for ironstone mining that were sunk in 1830 by Earl Fitzwilliam supplied local ironworks until about 1877, when the pit was converted to a colliery.
Mining from the 14-inch-thick ironstone bed became important near Emley in West Yorkshire in the 12th century. Monks came from Cistercian abbeys in other parts of Yorkshire to work the iron ore along its outcrop, particularly at Bentley GrangeShaft mounds and earthworks south of Bentley Grange Farm are the remains of a medieval iron mining site between Emley and West Bretton in West Yorkshire. , which at the time was the main centre of the iron ore industry.