Supporting Technical Assessments

EGL Ref: 8983 8 October 2021 Page 14 File: TSF3 Stability Analysis Appendix Summary.docx.doc FIGURE B9: NON MAGNITUDE-WEIGHTED 10,000-YEAR SA (1.0 S) DEAGGREGATION FOR MARTHA HILL MINE FOR CLASS B ROCK, VS30 = 600 M/S TABLE B12: ESTIMATED MEAN MAGNITUDES FOR 10,000 YEAR RETURN PERIOD SPECTRAL ACCELERATIONS Intensity Parameter Mean Magnitude (Mw) PGA 6.9 SA(0.5s) 7.3* SA(1.0s) 7.5* *Visually estimated from GNS 2017 deaggregation B7. EMBANKMENT SHEARWAVE VELOCITY PROFILE Zone C1, C2, D2 form the major proportion of the material within the embankment below the crest and will dominate the embankments response. The material for these zones is likely to be the more rocky overburden material. This material is likely to be crushed and conveyed to the Development Site, and transported and placed by dump truck in the embankment. The layers are placed in 0.25 to 0.5m thick layers and are track rolled with the loaded dump trucks or compacted with a CAT825. Placed in the embankment the material is a predominately a Sandy GRAVEL with some cobbles and silt. No direct measurement of shearwave velocity of the embankment material has been made. Estimates are based on empirical correlations for gravelly soils and depend on density and effective stress. These zones are drained within the embankment so the effective stress is the total weight of the material above. The gravel fill material is assumed to be a dense gravel with a relative density of Dr=0.85. A total unit weight of 20.5kN/m3 is used for the gravel fill.

RkJQdWJsaXNoZXIy MjE2NDg3