Butterley Company correspondence file on the Welbeck Estates Limited, relating to agreements on exchanges of coal under lands at Harlow Wood and Kirkby, Nottinghamshire, involving the Butterley Company and other colliery companies Involving the Bolsover Colliery Company, the Newstead Colliery Company, the New Hucknall Colliery Company and the Sherwood Colliery. Inlcuidng plans. Jul 1936-Dec 1946