Application study on complex wetting agent for dust-proof after gas drainage by outburst seams in coal mines

After gas drainage,the outburst seam is dry and,consequently,during subsequent mechanized mining,unwanted dust production is extensive.Because the hard dustfall typically has a small particle size it contains a high percentage of respirable dust.Considering these factors,this paper improved the efficiency of dustfall by reducing the surface tension of the liquid used as a wetting agent,then configuring five kinds of wetting agents by adopting various doses and types of surfactants,neutral inorganic salts and chemical additives,etc.After purchasing DA-85 and SRJ-1 wetting agent,the surface tension and critical micelle concentration of seven kinds of wetting agents were measured using the capillary rise method.Wetting agent A was confirmed to have the best comprehensive effect.The experiments were optimized by measuring and comparatively analyzing contact angles of pure water,SRJ-1 wetting agent and wetting agent A on the surface of different coal samples using a contact angle measurement instrument(HARKESPCA).By comparative analysis,dust-proof effects of seam,dynamic pressure water infusion and highpressure spray in the tunneling face at the Daning coal mine using pure water,wetting agent SRJ-1and A,it was determined that after using wetting agent A,the average dust concentration in the place of the mining machine driver,10 m and 110 m away from the tunneling front is approximately 300 mg/m~3,240 mg/m~3 and 100 mg/m~3,respectively.This practice increased the dust-proof efficiency dramatically and achieved a good comprehensive dust-proof effect.