Effect of ultralow frequency signaling on blasting array current.
Minneapolis, MN: U.S. Department of the Interior, Bureau of Mines, RI 9479, 1993 Jan; :1-11
The U.S. Bureau of Mines (USBM) has developed an electromagnetic (EM) fire warning alarm system for underground mines. The system generates a magnetic field for through-the-earth signal transmission to microreceivers carried by individual miners. EM fields can induce electric currents in metallic conductors; if an EM transmitting antenna and an electric blasting cap array are too close, the field could induce a current in the blasting array and cause zn unintentional initiation of the electric detonators. The USBM conducted tests that define the safe and unsafe regions for using electric detonators near the transmitting antenna of the warning alarm system.
Electromagnetic-radiation; Antenna-arrays; Human-factors-engineering; Safety-engineering; Ignition; Explosions; Blasting; Caps-explosives; Detonators; Electric-ignition; Mine-fires; Underground-mining; Warning-systems
Report of Investigations
NTIS Accession No.
Minneapolis, MN: U.S. Department of the Interior, Bureau of Mines, RI 9479