2008-12-10_REVISION - C1981010

• Permit No: C1981010
• IBM Index Class Name: Revision
• Doc Date: 12/10/2008
• Doc Name: Trapper G-Pit Landslide Mining Assesment
• From: Agapito Associates Inc
• Type & Sequence: PR6
• Media Type: D
• Archive: No

Junuarv 15, 2008 !'tWe iii
Liss OF FIGURES (CONCLUDED
PaQc
Figure 24. Highwall Slope Stability Failure at G-Strike Pit After September 2005 Failure ....... 38
Figure 25. Landslide Slope Failure at G-Dip Pit in October 2006 ............................................. 39
Figure 26. FLAC3D Model Geometry Developed to Analyze Stability ofG-Pit Landslide ...... 40
Figure 27. Failed Region for September 2005 Highwall Failure in G-Strike Pit as Predicted
By 31) Analysis from Displacements and Plastic Failure Indicators ......................... 41
Figure 28. Photograph of Failed Region for September 2005 Highwall Failure in G-Strike
Pit ........................................................................................................................... 42
Figure 29. Failed Region for October 2006 Landslide Failure in G-Dip Pit as Predicted by 31)
Analysis from Displacements and Plastic Failure Indicators .................................... 43
Figure 30. Aerial Photograph of Failed Region for October 2006 Landslide Failure in
G-Dip Pit ................................................................................................................ 44
Figure 31. Mine Plan for First Part ofZ-Dip Pit ....................................................................... 45
Figure 32. Photograph of Surface Cracking Associated with 2001 Highwall Failure in
G-Test Pit Downdip of Z,-Dip Pit Barrier Pillar Area ............................................... 46
Figure 33. Minor Near-Surface Failure Expected for Z-Dip Pit as Predicted by Previous
Failure Plastic Indicators and Low Equilibrium Velocities ...................................... 47
Figure 34. Photograph of'Z-Dip Highwall as of Cut #2 Illustrating Excellent Highwall
Condition ................................................................................................................ 48
Figure 35. Model Boundaries and Mining Sequence for East-Panel Pit and A-East Pit
Stability Analysis 9
Figure 36. FL.AC3D Model Boundaries ofEast-Panel Pit and A-East Pit Stability Analysis
Showing Surface Topography and Bedding and Simulated Mining Areas .............. .51
Figure 37. Proposed Mining Layout for K-Pit, G-Pit, East-Panel Pit, and A-East Pit
Along with Outline of Landslide Area .................................................................... .52
Figure 38. Schematic Example of'Mining in Steeply Dipping Beds Locations of'K-Pit
Outside the Landslide Area .................................................................................... .55
Figure 39. Proposed Locations of Groundwater Extraction and Monitoring Wells for
Lan(Fd1dC ............................................................................................................... .58
Agapito Associates, Inc.