| Year: | 1967 |
|---|---|
| Document Type: | USBI |
| Issuing Agency: | U.S. Bureau of Mines, |
| SUDOC: | I 28.27:8357 |
| Series: | Information circular / United States. Bureau of Mines ; |
| Report Number: | 8357 |
| Subjects: | Coal mines and mining--Safety measures |
| Coal mines and mining--United States | |
| Link: | https://hdl.handle.net/2027/mdp.39015078464412 |