A study of mine roof of the Pittsburgh and coal bed in the Pittsburgh mining district
Contributors: Plein, Leopold Nicholas, 1897- joint author.
Publisher: U.S. Govt. print. off.
Published: 1932
Place of publication: Washington
Language: eng
Number of pages: 98
Subjects: Mine timbering.; Coal mines and mining -- Pennsylvania.
Other titles: Roof of Pittsburgh coal bed, Pittsburgh district.