| Author: | Spencer, John D. |
|---|---|
| Year: | 1970 |
| Document Type: | USBI |
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, |
| SUDOC: | I 28.27:8479 |
| Series: | Information circular / United States. Bureau of Mines ; |
| Report Number: | 8479 |
| Subjects: | Coal mines and mining |
| Coal--Research | |
| Coal preparation | |
| Link: | https://hdl.handle.net/2027/mdp.39015078514745 |