Optically-powered Underground Coal Mine Communications

Emergency underground coal mine communication networks are discussed. Emergency communication systems should continue to operate following an explosion, major fire, roof collapse, or water inundation without relying on internal batteries or underground mine power. Optical fibre cables support Ethernet communication networks and power underground communication devices are proposed. The results of some tests with power-over-fibre technology have confirmed that 40 mW to 35 mW of power can be made available over a 0.5 km to 1 km length of fibre optic core, respectively. This is sufficient to power an underground SMS or email device.