"Installation of a model man cage at the Avoca Shaft of the Heidelberg Coal Co., Avoca, Luzerne County, Pa."; "Mather, Joseph V.", "McCleary, E. H."; "Mine safety.", "Coal mines and mining--Pennsylvania--Safety measures."; "McCleary, E. H.", "Mather, Joseph V."; "1947"; "

Serial issue. Issued as: United States. Bureau of Mines. Information circular, 7407 (1947).

"; ""; "P19458"; "pec"; "Coal mines and mining--Pennsylvania--Safety measures.", "Mine safety."; "14256"; .