Search U.S. government technical reports digitized or harvested by TRAIL.
Annual Report of Research and Technologic Work on Coal: Fiscal Year 1941
Annual Report of Research and Technologic Work on Coal: Fiscal Year 1942
First Organization and Work of the Coal-Mine Inspection Division, Bureau of Mines
Annual Report of Research and Technologic Work on Coal: Fiscal Year 1943
Annual Report of Research and Technologic Work on Coal: Fiscal Year 1946