"Growth of coal preparation in the smokeless fields of West Virginia."; "Guy, T. W."; "Coal mines and mining--West Virginia.", "Coal preparation plants--West Virginia.", "Coal preparation."; "Guy, T. W."; "1931"; "Serial issue. Issued as: American Institute of Mining and Metallurgical Engineers. Technical Publication, no. 437."; ""; "P6099"; "pec"; "Coal mines and mining--West Virginia.", "Coal preparation plants--West Virginia.", "Coal preparation."; "14256"; .