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Results 61 - 70 of 95
A new postdisaster communication and location system using through-the-earth electromagnetic wave propagation was tested at the Bureau of Mines Lake Lynn Experimental Mine. This describes the testing process and findings.
1/1/1983 - Contract reportsAn underground medium frequency radio communications system has been developed and demonstrated in both coal and metal/non metal mines. The principal advantage of the system are its low cost, ease of installation and the ability to provide radio communi...
9/1/1982 - Contract reportsA survey of the literature on extremely low-frequency and very low- frequency atmospheric noise was made.
7/1/1982 - Conference papersA new phone system was developed that provides eight full duplex communications channels over a single twisted shielded phone line, with no central switching station or line amplifiers. This system greatly simplifies installation and maintenance over th...
2/1/1982 - Contract reportsAn evaluation was made of one of several improved underground communication systems sponsored by the U.S. Bureau of Mines. The system was installed in a typical metal-nonmetal, room-and-pillar mine and utilized ultrahigh frequency repeaters connected to...
The Implementation of UHF Radio Communications and CCTV Monitoring Systems in a Room and Pillar Metal/Non-metal Mine3/1/1981 - Contract reportsThis report describes the design and implementation of UHF radio and closed-circuit television systems in the Black River room and pillar limestone mine near Butler, Pendleton County, Kentucky.
A survey of electromagnetic noise reports was performed and a summary of the results are given.
1/1/1981 - Contract reportsThis report describes the results of a measurement and analysis program to characterize wireless radio transmission in metal-nonmetal mines over a wide frequency range from 0.2 to 1,000 mhz and over a variety of mine environments.
10/1/1980 - Contract reportsThe object of this program was to extend the capabilities of visual paging systems both in size and functions in mines. The system developed uses the mine pager phone line for communication, monitoring, and remote control. The system was designed to be ...
7/1/1980 - Contract reportsThis report assesses the expected detectability, on the surface above mines, of electromagnetic signals produced in the 630- to 3,030-hz frequency band by a rescue transmitter activated by miners trapped underground. The implications of the results and ...