Timbering regulations in certain coal mines of Pennsylvania, West Virginia, and Ohio
Contributors: Calverley, Joseph Gladstone, 1886- joint author.; Sibray, Donald Loammi, 1898- joint author.
Publisher: U.S. Govt. print. off.
Published: 1930
Place of publication: Washington
Language: eng
Number of pages: 41
Subjects: Mine timbering.; Coal mines and mining -- Pennsylvania.; Coal mines and mining -- West Virginia.; Coal mines and mining -- Ohio.