Casgliadau Arlein

Handwritten in pencil on off-white, blue ruled paper. Notes and calculations relating to the Cefn Coed Colliery steam consumption and storage. The notes one side are dated 21-11-33 and the notes on the other side are dated 27-6-32. Loose within a green card file with all other documents with accession number 83.184I/67. The file is labelled 'Colliery Boiler Plant B31', 'Cefn Coed Data' and 'Colliery Engineering'.