Butterley Company correspondence file with the Welbeck Estates Company Limited on the extension of mining royalties for the Kirkby and Lowmoor Collieries Including loose summaries of leases for Kirkby Colliery, 2 Dec 1912, and Lowmoor Colliery, 3 Dec 1912, for Egmanton in the Ollerton mining area, with plan, c1930, extension of lease in accordance with exchange between the Butterley Colliery and the Sherwood Colliery Company, Jul 1930, and draft heads of terms for further leases for Kirkby and Lowmoor Collieries, 1930 Dec 1929-Dec 1930