Geologic investigations of underground coal mining problems /
McCulloch, C. M.
Geologic investigations of underground coal mining problems / C. M. McCulloch, P. W. Jeran and C. D. Sullivan. - Washington, D.C. : U.S. Dept. of the Interior, [1975] - 30 p. : ill. - Report of investigations / Bureau of Mines, U.S. Department of the Interior ; 8022 . - Report of investigations (U.S. Department of the Interior. 8022 .
92045007
Coal mines and mining.
Geologic investigations of underground coal mining problems / C. M. McCulloch, P. W. Jeran and C. D. Sullivan. - Washington, D.C. : U.S. Dept. of the Interior, [1975] - 30 p. : ill. - Report of investigations / Bureau of Mines, U.S. Department of the Interior ; 8022 . - Report of investigations (U.S. Department of the Interior. 8022 .
92045007
Coal mines and mining.