Figure 6 – Kaiser stress (σK) versus depth in the borehole for Boreholes drilled in the roof Figure 7– Kaiser stress (σK) versus depth in the borehole for Boreholes drilled in the sidewalls Based on the Kaiser-effect AE tests (loading along the core axis), the estimated stress shows a clear split between roof and sidewall cores. Roof samples (treated here as σv) give mostly moderate-to-high values in BH1, and the highest σK appears in the deeper intervals, which fits a transition from the disturbed zone near the excavation to more representative in-situ conditions. BH2 and BH3 roof dolomite are much lower and are likely underestimates due to disturbance and a weaker Kaiser onset. Sidewall cores (treated as σh in the drilling direction) show coherent, relatively high σK in anhydrite (~21.9–26.7 MPa), suggesting σh is close to σv. In contrast, sandstone sidewall values are very low (~4.9–8.6 MPa) and most likely reflect shallow sampling within the stress-relieve rather than the regional horizontal stress, with additional bias possible from coring/unloading damage and sample deterioration. 4. RESULTS AND ANALYSIS This pilot study tested whether acoustic-emission (AE) stress-memory methods can support in-situ stress estimation from oriented core in deep underground mining conditions. The Kaiser-effect approach worked best when the AE response showed a clear R² = 0.3395 R² = 0.672 R² = 0.7569 R² = 0.7691 0 10 20 30 40 0 2 4 6 8 10 12 14 16 18 σK [MPa] Depth in hole [m] BH1 - dolomite BH1-anhydrite BH2-dolomite BH3-dolomite R² = 0.8588 R² = 0.3206 R² = 0.6515 R² = 0.9108 0 5 10 15 20 25 30 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 σK [MPa] Depth in hole [m] BH1- sidewall (anhydrite) BH2- sidewall (anhydrite) BH3- sidewall (sandstone) BH4- sidewall (sandstone)
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