"Tursdale Colliery, in this parish [Cornforth], but in the township of Cassop-cum-Quarrington, is worked by Messrs. Bell Bros., where there are about 700 men and boys employed. Here the "Busty" seam is wrought at a depth of 100 fathoms, having an average thickness of four feet, but contains two bands, and iron-plate band and a sager band. The "Harvey" seam, two feet thick, is also met, but not at present worked ; and the "Brockwell" exists in the Hett district. The daily output averages about 760 tons of which about half is converted into coke, there being 211 ovens on the spot."

Whellan's 1894 Directory of County Durham via Durham Mining Museum