Figure 11

The distribution of gas extraction of the upper corner in August 2022 in the line chart Fig. 11 illustrates the distribution of gas extraction of the upper corner in August 2022. The gas concentration in the upper corner has always been below 0.8% but reaches the highest score of 0.74%. The gas problem can be resolved is shown after pre-extraction of high-level borehole gas. The gas extraction of buried pipes is realized in the Goaf before mining.