Results For the analysis, three areas of the mine were selected as they contain high quality source mechanisms calculated and events can be attributed to one of the categories discussed in Section 2. Figure 5 shows the clusters used in the analysis. Cluster A is dominated by crush-type events with P-axes orthogonal to the tunnels. These are interpreted to be episodes of sudden rock fracturing around tunnels. A few slip-type events are observed, presumably associated with the known structure in cluster B that could be extending further West. Cluster B, on the other hand, is dominated by slip-type events with P-axes close to vertical and for which one of the nodal planes correlate very well with a known structure (light red mesh that extends below the mine in Figure 5). A few crush-type events are observed in cluster B, particularly on the western side, after mining activities reached those areas in 2024. These crush-type events show close to vertically oriented P-axes, which could mean that these events, although having source mechanisms with implosive components, are driven indirectly by the stress re-orientation caused by the known fault nearby. Table 1 shows the stress measurements provided by the mine at two locations (Inostroza, 2022, Figure 5). Site 1 corresponds to a measurement performed outside the cluster Figure 4 Schematic representation of seismic data used in the proposed stress inversion method. F1-F3 are slip-type events with known structural origin. Events C1-C3 are crush-type events associated with tunnels (not stopes or large excavations). The yellow areas represented the fracture zone (seismic source), which is not necessarily symmetrical. Events S1-S4 are slip-type events associated with randomly oriented weaknesses. Reproduced with permission from Malovichko and Rigby (2024).
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