Radio propagation at 900 MHz in underground coal mines

This paper reports on experimental results of radio propagation in two unde rground coal mines, Measurements were performed at 900 MHz on horizontal an d vertical polarization in typical coal mine operational zones. Values of p ropagation loss in dB/100 m are derived. Additional losses due to coal mine curvatures and common coal mining equipment obstructions are also presente d. A hybrid tunnel propagation model consisting of the freespace propagatio n model and the modified waveguide propagation model is used to explain som e measurement results, Based on these results, we believe that microcellula r radio communications systems are feasible in coal mines.