Interim report on Britain Colliery's Silkstone Seam Report by FF Ridley of Newcastle-upon-Tyne on the character and cleaning process of coal found in the seam. An attached letter suggests that the findings should be treated as an interim analysis and for this reason greater emphasis is placed on the production and marketing aspect of the site. Each subject heading is clearly separated. Diagrams and tables of the data are attached as appendices. May 1939