### Article  
Testing the Utilization of a Seismic Network Outside the Main Mining Facility Area for Expanding the Microseismic Monitoring Coverage in a Deep Block Caving  
[PERSON] 1,2, [PERSON] 3,*, [PERSON] 3,4, [PERSON] 2, [PERSON] 5, [PERSON] 5,6, [PERSON] 2, [PERSON] 7, [PERSON] 7 and [PERSON] 7  
Footnote 12: https://www. +++ ==WARNING: Truncated because of repetitions==
[https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci)  
++  
the seismic-induced destruction involved [2; 4; 6]. This is due to rock mass removed, as the block caving process causes perturbations to already high stress regions in situ which may induce major earthquakes around cave areas. In such cases, seismic monitoring of block caving mining is required, especially for cave management and safety [1; 3]. The main problem in underground mining, especially deep mining at a depth of more than 1500 m, such as the Hongtoushan copper mine (1600 m) in Fushun, China, the Kidd copper-zinc mine in Canada (2800 m) and the Mponeng gold mine in South Africa (4350 m), is a high level of in situ stress caused by the thick overburden [2; 7]. The risk of induced seismicity due to the mining process increases as mining depth increases. In general, induced seismicity by mining processes is classified into two categories: (i) seismicity that is directly related to the stress changes caused by mining activities (blasting, hydrofracturing, caving, etc. ); and (ii) seismicity that is triggered by geological structural conditions [4; 8; 9]. Stress accumulation in underground mines occurs in the abutment and seismogenic zones [10]. The highest stress concentrations in these zones are caused by mass extraction when using the caving method [11]. Should ideal conditions be expected to obtain with respect to the mine design, cave propagation will occur in the direction of updip intrusion. However, in the case of incline intrusion, the rock mass in the hanging wall is also induced by the adjacent cave. The copper, gold and silver mines that are part of the Grasberg Operations of PT Freeport in Indonesia and China's Yanjingou gold mine are examples of mines with incline intrusion models with slopes of 45\({}^{\circ}\) and 49\({}^{\circ}\), respectively [12; 13]. Geomechanically, the stability challenge lies in the hanging wall area, which experiences compressional stress due to gravity on the inclined plane and the caving process. Should the induced stress be high, the rock mass can collapse, which can affect the direction of cave propagation. Uncontrolled cave propagation can result in an overbreak in the lithological boundary. This is not desirable because it will cause the mixing of high-grade ore with low-grade ore (dilution). To assess the risk of this possibility, it is necessary to monitor the seismogenic zone. The cave design of inclined intrusive deposits conforms to the intrusion limit to optimize the recovery and grade of ore. In incline intrusion ore bodies, generally, drift access for the haulage shaft path is deployed on the football side by considering the stability and confidence level of the rock mass strength value. Generally, seismometer networks in underground mines are deployed in the facility area due to the ease of access regarding deployment and they can be used to monitor the stress distribution in the rock mass around the tunnel development [14]. During development activities and the preparations for mine production, the seismometers installed in the facility area remain relevant. However, once production activities start, cave propagation in block caving mines should also be monitored. Therefore, the seismometer network is not ideal for monitoring microseismic activities throughout the block caving area. The objective of this research is to maximize the resolution of monitoring and minimize monitoring uncertainty in underground mines using the tomography method. Figure 1 shows the design of a seismometer network for an underground mine in an inclined intrusion geological setting.