Applications of Water Infusion for Dust Control in Underground Coal Mines—A Critical Review

Abstract

Coal mine dust continues to be a health and safety issue in underground coal operations. Water infusion method was developed and widely applied in European coal mines for dust control, and is now a common practice in most Chinese coal mines. This method typically involves the injection of water into the coal seam usually ahead of mining to increase its moisture content and therefore reduce dust generation during mining. Field practices indicated that it was possible to inject 9–15 l of water into 1 m3 of coal and increase its moisture content by approximately 1% with a respirable dust reduction of 40–65% during mining. A limited scale of water infusion trials was conducted in Appin and West Cliff collieries of Australia in late 1980s; a 30–50% reduction of dust levels was reported. With the availability of other dust control methods such as water spraying systems, water infusion method has not been considered as a viable means for dust mitigation in modern mines and as such it has not been utilised in Australian underground mines. The increase in production output and the deployment of more powerful equipment for coal cutting and transport, intensive SIS and UIS gas drainage practices mean that workers could be exposed to more dust contaminations. Whilst the mine operators are committed to suppress and dilute airborne dust particles using these passive measures, there is a need to critically examine and subsequently develop this proactive dust control technology for practical applications in Australian coal mines. The paper provides a critical review of the water infusion technologies in view of its technological advances and practical application limitations. The key parameters influencing the effect of water infusion on dust control are identified and discussed, particularly coal moisture content. The use of gas drainage boreholes as secondary water infusion holes is discussed.