Search U.S. government technical reports digitized or harvested by TRAIL.
Permissible electrically operated pumps
Mechanized mining brings new electrical hazards
List of permissible mine equipment approved during 1940
Inspection and testing of mine-type electrical equipment for permissibility
Some information on automatic coupling of mine cars
Permissible mine equipment approved during 1942
Prevention of fires caused by electric arcs and sparks from trolley wires
Permissible mine equipment approved during 1943