Year: | 1977 |
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Document Type: | USBI |
Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, |
Series: | Information circular - Bureau of Mines ; |
Report Number: | 8745 |
Subject: | Mine communication systems |
Link: | https://hdl.handle.net/2027/mdp.39015078464230 |