Gas comprehensive control technology of upper protective seam in contiguous outburst seams

According to the rapid outburst elimination and gas content over limit problems faced to the mining in upper protective seam incontiguous outburst seams of Datong No.1 mine,the mining seam hydraulic fracturing and permeability improvement technology,in seamhorizontal borehole and casing pre-drainage technology,adjacent protected seam floor passing through cross seam borehole pre-drainage,pressure released drainage,residual drainage technology,high level borehole drainage technology, U type + tail discharging ventilation modeand other gas comprehensive control technical measures were applied. The rapid outburst elimination of the protective seam face was real-ized. The gas drainage standard time was reduced by 90 days. The outburst predicted indexK1 andSwas never over the standard. The gasdrainage rate of the coa | mining face was 72.07%. The gas frequent over limit problem at the air retuning corner was completely solved andthe safety and high efficient mining of the mining and e xcavation alternation were ensured.