Fm-cw Electromagnetic Technique of Measuring Coal Layer Thickness.
Ellerbruch DA; Belsher DR
NTIS: PB 258 324 Available for Reference At Bureau Libraries :32 pages
An fm-cw microwave system was investigated for measuring coal layer thickness. Measurements were made in three mines near Pittsburgh, Pennsylvania, Fairview, West Virginia, and Coffeen, Illinois. Microwave frequencies in the range 1 to 2 ghz were used to measure samples up to 55 cm thick. All samples were backed with a naturally occurring shale. Measurements were also made on coal and shale samples compounded in the laboratory. The dielectric constant of coal apparently varies significantly within a coal seam. The form of the output signals from the fm-cw system seem to simplify the data interpretation and analysis process compared with the manually swept microwave system used previously. It appears that this technique has the potential of measuring changes in the dielectric constant of a coal seam and providing an output that can be used for real-time corrections in layer thickness measurement.
CP; Final Contract Report;
NTIS Accession No.
NTIS: PB 258 324 Available for Reference At Bureau Libraries
Nat'l Bureau of Standards