2009-09-21_PERMIT FILE - C1981010 ‎(13)‎

• Permit No: C1981010
• IBM Index Class Name: Permit File
• Doc Date: 9/21/2009
• Doc Name: Trapper G-Pit Landslide Mining Assesment, January 2008
• Section_Exhibit Name: Appendix T
• Media Type: D
• Archive: No

January 15, 2008
4.2.3 Geometry
Page 28
The model section was taken through the point 1,435,500E, 404,500N, at 7,400 ft
elevation (local coordinates 5500E, 4500N, 7,400) along a N70°E direction. The boundary of
the model extended from 5,495E to 7,665E. The model depth goes from the irregular
topographic ground surface down to an elevation of 6,750 ft. The geometry of the spoil pile
examined slope angles of 52° (1H:1.3V), 45°(1 H: IV), 40° (1.2H:1 V), and 37.6° (1.3H:1 V).
4.2.4 Material Properties
The same twenty-three material layers simulated in the G-Pit landslide FLAC313 model
analysis were used for this model. The assumed deformation and strength properties are shown
in Table 4 for each rock layer. The Mohr-Coulomb constitutive model was assigned to all layers.
The ubiquitous-joint constitutive model was assigned only to the Q-Floor mudstone layer. The
bedding of the Q-Floor mudstone assumed initial strength values of zero cohesion and tension,
and 15 ° friction. The bedding strength in the Q-Floor mudstone assumed 15° for peak strength
and for 5° residual strength. The strain-softening behavior of spoils assumed peak friction
strength of 40° and residual friction strength was 30° for inelastic strains greater than 5%.
Table 4. Mechanical Properties Used in the G-Pit Spoil Stability FLAC Model
Young' RM RM RM
Density Modulus, E Poisson' Cohesion Friction Tensile
Layer Strata (lb/ft) (psf x 106) Ratio (ksf) (°) (ksf)
1 OB, MS 134.2 26.4 0.32 2.5 15.9 1.5
2 H Seam 80.9 16.2 0.34 3.9 28.6 1.0
3 H Floor, SS 131.8 79.7 0.23 17.6 43.1 5.0
4 11 Seam 80.9 16.2 0.34 7.9 18.2 0.7
5 11-12 Intb, SS 136.5 79.7 0.23 25.0 40.6 6.7
6 12 Seam 80.9 16.2 0.34 16.7 18.7 1.4
7 12-K Intb, SS 144.8 120.0 0.18 36.8 29.6 3.7
8 MK Seam 79.8 16.2 0.34 21.0 17.1 1.6
9 MK Floor, MS 153.7 9.1 0.40 35.5 14.4 2.4
10 ML Roof, MS 135.7 9.1 0.40 11.9 3.4 0.8
11 ML Seam 83.6 23.4 0.32 25.3 15.9 1.6
12 ML Floor, MS 133.7 45.1 0.40 21.3 6.1 3.9
13 ML Floor, SS 156.6 418.7 0.17 98.9 33.7 65.9
14 L-M Intb, MS 145.8 48.1 0.37 55.7 19.9 8.9
15 M Roof, SS 133.9 190.7 0.17 67.0 23.7 16.9
16 M Roof, MS 138.0 48.1 0.37 51.6 8.9 12.5
17 M Seam 80.9 24.4 0.27 33.1 14.7 1.7
18 M Floor, MS 150.6 48.1 0.37 61.9 11.3 30.2
19 Q Seam 80.7 24.4 0.27 34.8 16.6 3.2
20 Q Floor, MS 134.8 48.3 0.37 35.1 5.8 5.1
21 Q Floor, SS 132.1 46.8 0.38 64.2 20.0 1.8
22 R Seam 80.9 25.1 0.27 23.3 8.8 0.6
23 R Floor, SS 152.3 71.1 0.24 91.3 25.8 6.0
Spoil 125 3.9 0.35 0 55 0
Agapito Associates, Inc.