Geology, Mining, and Methane Content of the Freeport and Kittanning Coalbeds in Indiana and Surrounding Counties, Pa

by A. Y. Lee, Anthony T. Iannacchione, Barbee J. Scheibner, Donald G. Puglio, Harry V. Makar, Hon-chung Ko, Natesa I. Jayaraman, R. H. Lien, Seth C. Schaefer, United States. Bureau of Mines, B. J. Wiegard, D. A. Martin, G. E. Daut, William I. Nissen · 1979