| Year: | 1943 |
|---|---|
| Document Type: | USBI |
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, |
| SUDOC: | I 28.27:7268 |
| Series: | Information circular ; |
| Report Number: | 7268 |
| Subjects: | Coal mines and mining--Safety regulations--United States |
| Mine inspection--Standards--United States | |
| Lignite industry--Standards--United States | |
| Bituminous coal industry--Standards--United States | |
| Link: | https://hdl.handle.net/2027/mdp.39015074127039 |