| Year: | 1948 | 
|---|---|
| Document Type: | USBI | 
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, | 
| SUDOC: | I 28.27:7449 | 
| Series: | Information circular / Bureau of Mines ; | 
| Report Number: | 7449 | 
| Subjects: | Coal mines and mining--Safety measures | 
| Anthracite coal | |
| Link: | https://hdl.handle.net/2027/mdp.39015077578550 |