Correspondence file of H. Eustace Mitton on the visit of Institution of Mining Engineers Lighting Committee to Nunnery Colliery in Sheffield Including draft copies of report of the visit on 8 Sep 1932 and "The Times Trade and Engineering Supplment", 3 Sep 1932, which include a photograph of the lighting of the Nunnery Pit coal face on page 3 Aug 1932-Oct 1932