## 3 Overview and Mechanism of Mining-Induced Earthquake Events at the 3308 Working Face  
### Overview of Mining-Induced Earthquake Events  
On 10 September 2022, a high-energy mining-induced earthquake occurred during the initial extraction phase at the 3308 fully mechanized caving face of the Yangcheng Coal Mine. According to the analysis by the mine's SOS microseismic monitoring system, a fracture occurred in the roof ahead of the 3308 fully mechanized caving face at 14:38:25 on 10 September, with an energy release of 3.06 \(\times\) 10\({}^{5}\) J. Feedback from underground personnel indicated that a tremor was felt at the 3308 working face, accompanied by a sudden strong airflow from the goat direction. Minor spalling and coal dust were observed in the advanced section of the track roadway, but there were no occurrences of rib spalling, floor heave, roof subsidence, or support damage, and no tremors were felt on the surface. This mining-induced earthquake drew the attention of local government officials and the mine leadership, leading to a halt in production at the 3308 working face until December of the same year. On 20 December 2022, another high-energy mining-induced earthquake event occurred during the resumption of extraction at the 3308 face. According to the SOS microseismic monitoring system's analysis, this event took place on 20 December at 20:55:42, due to damage to the floor ahead of the 3308 face, with an energy release of 1.06 \(\times\) 10\({}^{5}\) J. Based on site feedback, underground conditions remained safe, with no impact on personnel or equipment, and all operational conditions were normal. Based on the dynamic manifestations observed during the two mining-induced earthquakes, as well as feedback from on-site personnel, it is evident that although neither event resulted in casualties, severe damage to roadway and mining space surrounding rock, or equipment destruction, both caused noticeable tremors felt by workers at the face and inflicted varying degrees of damage to the surrounding rock in the roadway. There was even a distinct tremor felt in the surface industrial area. Therefore, it is essential to  
Figure 4: Spatial arrangement of microseismic sensors around the 3308 working face at Yangcheng Coal Mine. analyze the generation mechanisms and precursor characteristics of these two high-energy mining-induced earthquake events at the working face to effectively prevent destructive rockburst hazards triggered by high-energy mining-induced earthquakes. Analysis of Mine Pressure Manifestations in Roadways Before and After High-Energy Mining-Induced Earthquakes  
When deploying stress sensors, the staff at the Yangcheng Coal Mine performed an initial calibration and established a periodic inspection cycle, with checks conducted every two days to ensure the sensors' proper operation and data accuracy. The calibration procedure included verifying the sensor's response to known reference loads, allowing inspectors to fine-tune its sensitivity and ensure reliable data collection. Additionally, Yangcheng Coal Mine used a calculation formula to convert the electrical signals recorded by the sensors into actual stress values, taking into account the sensor's calibration coefficients and environmental factors. This process enabled the mine to obtain precise stress measurements, accurately reflecting the stress changes within the rock mass. These calibrated values were then used for further analysis of stress variations related to mining-induced seismic events. \[\sigma=\frac{V_{out}-V_{ref}}{S} \tag{1}\]  
where \(\sigma\) represents the actual stress value, \(V_{out}\) is the sensor's output voltage, \(V_{ref}\) is the reference voltage, and \(S\) is the sensitivity of the sensor. This formula allows us to convert the electrical signal into precise stress values, ensuring the reliability of the monitoring data.