Advance of fiber optic gas sensors for coal mine safety applications

Coal mine combustion is major safety hazard, which is conventionally detected by monitoring characteristic gases such as CO, C₂H₄ and C₂H₂, using a tubing bundle gas sampling system and gas chromatograph mess spectrometer. IR gas sensors have been developed to overcome the complexity and cumbersomeness of the GC analyzer, however, cross sensitivity among gases in the IR region affects the detection sensitivity and reliability. Fiber optic multi-gas sensors have been developed which provides advantage of real time detection, low cross sensitivity and low cost for coal mine combustion detection. We report latest development of a multi-gas sensor which has sub-ppm detection sensitivity. The sensors exhibit great potential for on site real time gas monitoring in coal mines and offer the advantage of early detection and warning of coal combustion.