Butterley Company correspondence file on arbitration between the Butterley Company and the Duke of Portland, relating to workings of the Portland Colliery and Kirkby Colliery, involving the taking over of the lease to work by the New Hucknall Colliery Company Including some price lists - for the Butterley Company, 23 Nov 1891, Ormonde Colliery, 29 Oct 1913 and Riddings Colliery for Coates Park and Tunnel Pit, early 20th cent May 1911-Jul 1911