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Typed in black ink on off-white paper, with details handwritten in pencil and blue ink. National Coal Board South Western Division headed paper. A letter addressed to I. Williams of Powell Duffryn Ltd. containing figures relating to the maximum demand and electrical units generated during 1948 at Powell Duffryn Ltd. Loose within pink/peach card file with other documents relating to Middle Duffryn and Bargoed High Pressure Station.
