Butterley Company correspondence file on the agreements made about minerals leased from the Duke of Portland, to support the Great Central Railway Tunnel at Annesley, and on compensation given by the railway company Including Plan A of the Mansfield Railway, early 20th cent, and plan showing the coal in the Top Hard coal seam to be left to support Annesley Tunnel, Jul 1914, copy of memorandum of agreement, and minutes of meeting between representatives of the Great Central Railway Company and Butterley Company, 7 May 1914. Feb 1914-Dec 1915