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Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine, McElroy Mine, located near Moundsville, West Virginia. The electromagnetic environment created by 300 volt dc and 480 volt ac machinery was measured. In one technique noise was measured over the entire electromagnetic spectrum of interest for brief time periods. The noise was recorded using broadband analog magnetic tape. The noise data was later transformed to give spectral plots. In the other technique, noise amplitudes were recorded at several discrete frequencies for a sufficient lenght of time to provide amplitude probability distributions. The specific, measured results are given in a number of spectral plots and amplitude probability distribution plots.
| Author(s): | Kanda-M, Adams-JW, Bensema-WD |
| Reference: | U.S. Department of the Interior, Bureau of Mines, Contract No. H0133005. NTIS No. Com/741-1717, 1974; :1-156 |
h0133005-4 (PDF, 5606 KB) (image based PDF - searchable with Adobe Reader 7)
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