Study on critical value of K₁ of outburst risk prediction index of working face

Taking No. 3 coal seam of Zhongling No.1 Mine as an example, this paper introduces a progressive method to determine the K₁ critical value of outburst risk in working face, which is consists of hypothesis, investigation, correction and determination. Firstly, the reasonable critical initial value of K₁, the desorption index of drilling cuttings gas in No.3 coal seam was determined based on statistical analysis of historical data and theoretical calculation in laboratory, which lay a foundation for on-site investigation and correction; secondly, through statistical analysis of the prediction history data of working face, the gas occurrence distribution law in the prediction area of the working face was clarified, the site investigation area of the mining working face was determined; according to the investigation results, the critical initial value of K₁ was analyzed and corrected; the extended application test was carried out for the modified critical initial value of K₁; the modified critical initial value of K₁ was tested with extended application; the critical value of K₁ of outburst risk in No.3 coal seam working face was finally determined as 0.55 mL/(g·min^1/2) and its application conditions were also determined, which verified the feasibility of the research method.