Falls of roof in mines operating in the Pittsburgh Coal Bed, West Virginia / by J.W. Paul and J.N. Geyer.
Saved in:
Main Author: | |
---|---|
Corporate Author: | |
Other Authors: | |
Format: | Government Document Book |
Language: | English |
Published: |
Washington :
U.S. Govt. Print. Off,
1933.
|
Series: | Technical paper (United States. Bureau of Mines) ;
547. |
Subjects: |