Search U.S. government technical reports digitized or harvested by TRAIL.
State laws relating to coal-mine timbering
Analyses of Kansas coals / [by the U.S. Bureau of Mines].
Falls of roof and coal in mines operating in the Sewickley coal bed in Monongalia County, W. Va.
Blasting practices as they affect the roof of coal mines in Ohio, Pennsylvania, and West Virginia
Falls of roof in mines operating in the Pittsburgh Coal Bed, West Virginia