Gas Control Technoloy of Coal Mining Face in Contiguous Protective Seam

A study was conducted on the gas emission law of No.5767 coal mining face in a protective seam of Wulan Mine.According to the conditions of No.7 seam and the below seam No.8 seam,the comprehensive gas control method was provided,including the gas drainage with boreholes drilling along the mining seam,the gas drainage with high upward inclined boreholes in the air returning gateway,the pressure releasing and gas drainage with the surface drilling,the buried pipeline gas drainage in the mining goaf,the gas drainage with boreholes drilling through the mining seam.An investigation was conducted in the gas control effect.The results showed that with the comprehensive gas control measures conducted,the gas content over limite problem during the mining period of No.5767 coal mining face was effectively solved.The ventilation quantity of the coal mining face was reduced from previous 1 700 m3/min to 700 m3/min,the gas volume fraction in the air retuning flow was 0.32%~0.60% and the safety mining of the coal mining face could be ensured.