Demonstration On Effect Of Drilling Extraction Regional Outburst Prevention Measures In Unprotected Area Of Protective Layer Mining For Xinglong Mine

At present, gas disaster accident of mine is prone in China, especially coal and gas outburst accident is most harmful. In order to prevent coal and gas outburst accident, regional outburst prevention measures must be carried out. Gas pre-extraction through drilling is a major regional outburst prevention measures of protective layer mining in unprotected area. According to requirement for regional outburst prevention measure of “quaternity”, regional outburst prevention effect must be tested after implementing regional outburst prevention measures. Due to complexity of coal mine condition and diversity of outburst characteristic, index selection and technical scheme of outburst prevention effect test need to be further studied. As a consequence, this paper takes the first mining face of 4# coal seam at non-protected area of Xinglong coal mine of Nantong mining limited liability company as an example and according to combining methods of field test and theoretical calculation, technology methods of drilling regional outburst prevention effect test was taken into studied. The major conclusion and results of this paper can be drawn that:①According to the coal seam gas occurrence condition in unprotected area of protective mining, as well as gas flowing state in coal seam and coal seam gas flow theory around drillings, the technological theory was analyzed on decreasing outburst dynamics and increasing outburst prevention ability of mine through drilling gas extraction and drainage through drillings.②According to the coal seam gas occurrence conditions of the research scope and its surrounding, the reasonable effect test scheme of regional outburst prevention measures was put forward.③According to requirement for the effect test scheme, "M" type of reasonable arrangement of borehole drillings for measuring coal seam gas pressure and coal seam gas content was put forward and the residual gas pressure value measured and residual gas content value measured within the scope of effect test were received.④Taking mining radius and gas emission of adjacent layer into consideration and according to the relation of The original gas reserves to gas extraction and drainage, residual gas content within the scope of test was calculated. According to residual gas content, the residual gas pressure was theoretically received.⑤According to comparative analysis of the theoretical and measured residual gas pressure and the residual gas content and their outburst dangerous critical value, reaching Standard range of regional outburst prevention effect was demarcated.