| Author: | Butner, D. W. |
|---|---|
| Year: | 1948 |
| Document Type: | USBI |
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, |
| SUDOC: | I 28.27:7451 |
| Series: | Information circular / United States Department of the Interior, Bureau of Mines ; |
| Report Number: | 7451 |
| Subjects: | Boring |
| Mines and mineral resources--California | |
| Boring machinery | |
| Diamond bits | |
| Link: | https://hdl.handle.net/2027/mdp.39015077578402 |