### Spatial Evolution of Mining-Induced tremors near Main Roadways in Gaoijapu Coal Mine
Thus, on 4 November 2018, another rockburst occurred in the main roadways (as is shown in Figure 2), with floor heave in the range of about 73 m in regard to the belt roadway and roof fall in the range of about 123 m in regard to the return air roadway. As is shown in Figure 3d, after 4 November 2018, due to this accident, the entire mine was forced to shutdown. During the period from 1 November 2018 to 31 December 2018, although no working face mining took place, many strong tremors still occurred near the main roadways. Figure 4 shows the spatial evolution of mining-induced tremors caused by mining at a single-sided working face. After the rockburst on 4 November 2018, the coal mine resumed production in May 2019. This rockburst accident had led to a five-month-long shutdown of the coal mine. As is shown in Figure 4a, from June 2019 to September 2019, mining began at the 204 working face and there was only one mining working face near the main roadways. Due to the increased distance between the working face and the main roadways, the degree of mining tremor activities had significantly decreased compared to the activities displayed in Figure 3. This indicates that the simultaneous mining of  
Figure 3: The spatial evolution of mining-induced tremors when mining on both sides of the main roadway: (**a**) 1 January 2018 to 31 March 2018, (**b**) 1 April 2018 to 30 June 2018, (**c**) 1 July 2018 to 31 October 2018, and (**d**) 1 November 2018 to 31 December 2018.  
two working faces has a greater influence on rockbursts in main roadways compared to mining a single working face. Figure 4b shows that during the period from April 2020 to June 2020, although the 204 working face and the 205 working face were in production simultaneously, because of the relatively long distance between the two working faces and the main roadways, the influence of the mining on the main roadways gradually weakened. The degree of mining-induced tremor activities was significantly reduced compared with the activities displayed in Figure 3a,b. This indicates that the influence of mining working faces on both sides of main roadways is greater than that from a single-sided working face. Figure 5 shows the time series of mining-induced tremors occurring near the main roadways in the Gaoijapu coal mine. As is shown in Figure 5, during the simultaneous mining of the 104 and 203 working faces, the number of tremors had an obvious correlation with the distance between the two working faces and the main roadways. The closer the distance between the working faces and the main roadway, the stronger the frequency and energy of the tremors occurring near the main roadways. After November 2018, even when the entire mine was shutdown, the frequency and cumulative energy of the tremors near the main roadway remained high. Such activity then gradually returned to a relatively low level four months later. This indicates that the influence of mining at the working face on main roadways lasts for a long time. Figure 4: The spatial evolution of mining-induced tremors caused by the mining of a single-sided working face: (**a**) 1 June 2019 to 30 September 2019, (**b**) 1 April 2020 to 30 June 2020. Figure 5: Time series of tremors near main roadways in Gaoijapu coal mine.