The results of the stress inversion are shown in Figures 6-8 (cluster A), Figure 9-11 (cluster B) and Figure 12 (cluster C). For cluster A, the results yield an estimated σ1 azimuth and plunge of 288º/36º (Figure 8), which are values close to the stress measurements at site 2 (Table 1), 290º/17º, although site 2 is not within cluster A. These orientations are roughly perpendicular to the tunnels, which suggest that stresses in this area are mostly driven by tunnel geometry. For cluster B the values are 280º/64º (Figure 11), meaning that σ1 is dipping more steeply in this area. This result correlates with site 1 stress measurement (Table1), 271º/77º, although site 1 is not within any of the clusters analysed (Figure 5). Cluster C consists purely of slip-type events that are located far from mining and do not correlate with a known structure. The stress inversion in this case results in σ1 with an azimuth of 242º and a plunge of 57º (Figure 12). In terms of the inferred stress ratios, R=|(|σ1|-|σ2|)/(|σ1|-|σ3|), the inverted values for clusters A, B and C are of 0.76, 0.56 and 0.70, respectively. These results correlate well with the value from the stress measurements (Table 1). Table 1 Stress measurements organized by the mine (Inostroza, 2022). Site 1 is a location away from mining and not within the cluster volumes selected. Site 2 is within cluster B but away from the structure (Figure 5). Site σ1 (MPa) Az (º) Pl (º) σ2 (MPa) Az (º) Pl (º) σ3 (MPa) Az (º) Pl (º) R 1 28.86 271.10 76.80 17.99 106.80 12.70 12.90 16.00 3.40 0.68 2 38.66 290.00 16.50 15.53 186.70 37.60 9.39 39.00 47.70 0.79
RkJQdWJsaXNoZXIy MTM0Mzk2