| Author: | Crawford, Frank Stevens, |
|---|---|
| Year: | 1932 |
| Document Type: | USBM |
| Issuing Agency: | U.S.Bureau of Mines, |
| SUDOC: | C 22.5:515 |
| Series: | Technical paper / United States. Bureau of Mines ; |
| Report Number: | 515. |
| Subjects: | Iron mines and mining--Superior, Lake |
| Iron mines and mining--Safety measures | |
| Link: | https://hdl.handle.net/2027/mdp.39015077559154 |