Electromagnetic wave propagation in an asymmetrical coal seam

Electromagnetic wave propagation in a coal seam is analyzed for the case where the surrounding floor and roof rocks have different electrical properties. Numerical results are presented for the attenuation rate and field distribution of the dominant mode. Even when the roof and floor conductivities are different, the vertical electric field and the horizontal magnetic field are the dominant components, and they are nearly constant within the coal seam. The results have application to mine communication and remote sensing of coal seams.