Research on Fire Prevention Technology of Coal Mining Face in Shallow Depth Seam Under Large Air Leakage Firing Zone

According to No.30106 and No. 30107 coal mining faces in No. 3-1seam of Longhua Mine had shallow mining depths and above the coal mining faces w as a large air leakage firing zone in No.2-2seam, the scope of firing zone was large and other problems, in combination with the firing zone features in No.2-2seam, th e comprehensive control measures were conducted, including grouting sealing technology, nitrogen injection for fire prevention and control, pressure balanced ventilati on for No.30106 and No. 30107 coal mining face. The CO volume fraction in the borehole above No. 30106 coal mining face was reduced from 12 000 x 10-6to below 3 00 x 10-6and the CO volume fraction at the upper corner was basically kept below 24 x 10-6. The safety mining and withdrawing of the coal mining face was ensured.