Supporting Technical Assessments

1.54 Distance 200 300 400 500 600 700 800 900 Elevation 30 50 70 90 110 130 150 170 Color Name Model Unit Weight (kN/m³) Cohesion (kPa) Efective Cohesion (kPa) Efective Friction Angle(°) Strength Function Phi-B (°) Minimum Strength (kPa) Tau/Si gma Ratio Piezometric Line Ru Include Ruin PWP PSTEQ Ash/CWRock/Resid.S SHANSEP 17 0 0.23 1 No PSTEQEW/VWRhy. EWIgn&Dac Shear/NormalFn. 17.5 EW/VWRhy. EWIgn.Dac. 0 1 No PSTEQSPZoneD2 Shear/NormalFn. 19.5 Grav./Cobb. Dr=0.85 (16%ile) 0 1 0.05 Yes PSTEQSPZoneD3 Mohr-Coulomb 19 8 15 0 1 0.4 Yes PSTEQSPZoneE SHANSEP 19 0 0.06 1 0.6 Yes PSTEQVWDacite Shear/NormalFn. 18 VWDacite 0 1 No PSTEQWDacite Shear/NormalFn. 25 WeakRhy. Dac. 0 1 No PSTEQWRhyRock Shear/NormalFn. 18.5 WeakRhy. Dac. 0 1 No PSTEQZoneA/IFdtn UC SHANSEP 17.5 50 28 1 0.3 Yes PSTEQZoneA/IMine OB SHANSEP 20.5 120 0.32 1 0.1 Yes PSTEQZoneF Shear/NormalFn. 20.5 Grav./Cobb. Dr=0.85 (16%ile) 0 1 0.05 Yes PSTEQZoneG Undrained(Phi=0) 20.5 80 1 No 20.482 m 42.395 m 146.3 m 11.3 m 20.528 m 54.316 m 47.043 m Factor of Safety 1.54 - 1.64 1.64 - 1.74 ≥ 1.74 13/10/2021 Section 2a.gsz Figure B23a North Slope PSTEQ 1:4,000 By: ET Analysis Settings Method: Morgenstern-Price Direction of movement: Left to Right Slip Surface Option: Entry and Exit Unit Weight of Water: 9.807 kN/m³ Horz Seismic Coef.: Factor of Safety: 1.54 Color Name Model Unit Weight (kN/m³) Cohesion (kPa) Effective Cohesion (kPa) Effective Friction Angle (°) Strength Function Minimum Strength (kPa) Tau/Sigma Ratio Piezometric Line Ru Include Ru in PWP PSTEQ Ash/CWRock/Resid.S SHANSEP 17 0 0.23 1 No PSTEQ EW/VW Rhy. EW Ign&Dac Shear/Normal Fn. 17.5 EW/VW Rhy. EW Ign. Dac. 1 No PSTEQ SP Zone D2 Shear/Normal Fn. 19.5 Grav./Cobb. Dr=0.85 (16%ile) 1 0.05 Yes PSTEQ SP Zone D3 Mohr-Coulomb 19 8 15 1 0.4 Yes PSTEQ SP Zone E SHANSEP 19 0 0.06 1 0.6 Yes PSTEQ VW Dacite Shear/Normal Fn. 18 VW Dacite 1 No PSTEQ W Dacite Shear/Normal Fn. 25 Weak Rhy. Dac. 1 No PSTEQ W Rhy Rock Shear/Normal Fn. 18.5 Weak Rhy. Dac. 1 No PSTEQ Zone A/I Fdtn UC SHANSEP 17.5 50 28 1 0.3 Yes PSTEQ Zone A/I Mine OB SHANSEP 20.5 120 0.32 1 0.1 Yes PSTEQ Zone F Shear/Normal Fn. 20.5 Grav./Cobb. Dr=0.85 (16%ile) 1 0.05 Yes PSTEQ Zone G Undrained (Phi=0) 20.5 80 1 No

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