Experimental Study on Coal Fly Ash-Based Gas-Sealing Coating Used for Coal Mine Roadway Walls

Gas-sealing coatings on coal mine roadway walls can effectively repress gas emission and are of importance to the safe operation of coal mining. In this study, the performance of coal fly ash (CFA)-based gas-sealing coatings was investigated, including the aspects of drying time, air tightness, impermeability, flame retardancy and antistatic properties. The results show that coating No. 25 with 60 g ultrafine CFA and 50 g emulsion (curing at 22 °C) had the best air tightness, with a permeability coefficient of 2.95 × 10−13 cm2/(s·Pa). The data obtained through the self-developed air tightness test device agreed well with the detection results of the gas permeameter, thus verifying the accuracy and reliability of the device. The impermeability, flame retardancy and antistatic properties of coating No. 25 conformed the requirements of voluntary national standards GB/T 23445-2009 and coal industry standard MT113-1995, respectively. The CFA-based gas-sealing coating in the pilot test reduced the gas emission intensity by 40%–50%. It could have wide applications in coal mine roadway walls.