Butterley Company correspondence file on the Low Main seam at Pentrich and Wingfield collieries Relating to the Butterley Company's offer to lease the remaining part of the Low Main seam not already worked by the Pentrich Colliery Company Ltd and the Pentrich Colliery Company's offer to sublease another part of the same seam at the Swanwick fault line from the Wingfield Manor Colliery Company. Includes coloured plan to accompany Mr Mitton's letter of 15 Jun 1915, Jun 1915, scale 6 inches to 1 mile, 35cm x 25cm. Plan of Pentrich Colliery showing coal royalty and workings in the Low Main seam, early 20th cent, scale 6 inches to 1 mile, 44cm x 30cm. Apr 1915-Jul 1916