Search U.S. government technical reports digitized or harvested by TRAIL.
Use of reflector buttons for danger, warning, direction, and safety signs in mines
Use of respiratory protective devices under abnormal air pressure
Prevention of fires caused by electric arcs and sparks from trolley wires
Ground-resistance measurements of drill-hole casings
Mine rescue life-line telephone assemblies
Ignition and control of burning of coal mine refuse
Demonstration and evaluation of five methods of secondary backfilling of strip-mine areas