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Apparent earth conductivity over coal mines as estimated from through-the-earth electromagnetic transmission tests.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8869, 1984 Jan; :1-18
Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate pedictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.
Noise-exposure; Noise-frequencies; Noise-pollution; Noise-protection; Noise-transmission; Noise-waves; Electrical-fields; Electrical-measurement; Electrical-waves; Magnetic-fields; Magnetic-properties; Miners; Mining-industry; Electromagnetic-fields; Electromagnetic-wave-transmission; Electromagnetic-energy; Mine-shafts
IH; Report of Investigations
NTIS Accession No.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8869