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Costs of mining under bolted roof and timbered roof in bituminous coal mines
| Author: | Ackerman, M. J. |
|---|---|
| Additional Authors: | Wallace, Joseph J. |
| Year: | 1961 |
| Document Type: | USBI |
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, |
| SUDOC: | I 28.27:8024 |
| Series: | Information circular / Bureau of Mines ; |
| Report Number: | 8024 |
| Subjects: | Coal mines and mining |
| Bituminous coal | |
| Link: | https://hdl.handle.net/2027/mdp.39015078461558 |
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