Roof movement study of mechanized retreating longwall operation, Lancashire no. 15 mine, Bakerton, Cambria County, Pa. /
Saved in:
| Language: | English |
|---|---|
| Format: | U.S. Federal Government Document Book E-Resource |
Table of Contents:
- "January 1954."
- "Int. - Bu. of Mines, Pgh., Pa."--p. 13.