Abstract: In this paper, firstly, the basic principles of gas content method was be used to predict coal and gas outburst and the calculation method of gas loss quantity , were introduced. Drilling coal core in the depth of 15m, 25m, 30m,35m,45m,60m in the 3012 work face of Yonghong, the values of gas loss quantity Q1, gas content of underground mine and laboratory Q2, gas content of Smash Q3 were measured using the gas content method , and the effect of different sampling depth in the same seam on the measured value of gas content was compared and analyzed. At the same time, the site inspection were carried out. On the basis of the comparison and analysis, it can be concluded that the measured gas concentration of the coal core in the depth of 30-35 m can be regarded as the the original coal seam gas content.

Key words: gas content method, gas loss quantity, sample depth