2010-12-17_REVISION - C1981019 ‎(94)‎

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 12/17/2010
• Doc Name: Exhibit 23 Item 1 Geotechnical Report -Collom Temporary Spoil Pile & Pond
• Type & Sequence: PR3
• Media Type: D
• Archive: No

• SHANNON 6WILSON, INC.
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY .............................................................................. ............................... i
1.0 INTRODUCTION .................................................................................... ..............................1
2.0 PROJECT DESCRIPTION ...................................................................... ..............................1
3.0 SUMMARY OF PREVIOUS WORK ..................................................... ..............................2
4.0 FIELD EXPLORATION AND LABORATORY TESTING .................. ..............................3
5.0 GEOLOGIC AND SOIL CONDITIONS ................................................ ..............................4
5.1 Geology ........................................................................................ ..............................4
5.2 Landslides ..................................................................................... ..............................5
5.3 Underground Mining .................................................................... ..............................5
5.4 Soil and Groundwater Conditions ................................................ ..............................5
6.0 STABILITY ANALYSIS MODEL AND PARAMETERS .................... ..............................6
6.1 Model
Development and Geometry ............................................. ..............................7
6.1.1
Clay Layer at Base of Spoil Model ................................ ..............................7
6.1.2
•
Carbonaceous Mudstone (CMS) at Base of Spoil Model ............................8
6.2 Selection of Model Parameters .................................................... ..............................8
6.2.1
Spoil ............................................................................... ..............................8
6.2.2
Clay Layer ...................................................................... ..............................9
6.2.3
Carbonaceous Mudstone / Clay Shale ........................... ..............................9
6.2.4
Clayey Gravel and Bedrock .......................................... .............................10
6.2.5
Groundwater Conditions ............................................... .............................10
6.2.6
Pseudo - Static Analysis .................................................. .............................10
7.0 RESULTS OF STABILITY ANALYSIS ............................................... .............................10
8.0 CONCLUSIONS AND RECOMMENDATIONS .................................. .............................12
8.1 Spoil Fill Placement .................................................................... .............................12
8.2 Spoil Fill Underdrain ................................................................... .............................12
8.3 Surface Water Control and Topsoil Cover .................................. .............................13
8.4 Short-Term Stability of Slopes .................................................... .............................13
8.5 Review of Additional X -Seam Drilling ...................................... .............................14
8.6 Sedimentation Pond Embankment .............................................. .............................14
9.0 MONITORING ....................................................................................... .............................15
10.0 LIMITATIONS ....................................................................................... .............................16
• 11.0 REFERENCES ........................................................................................ .............................17
23 -1- 01101- 400- R1.docx/wp /lkn 23 -1- 01101 -400
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Exh. 23 -1 -6 Revision Date: 08/05/09
Revision No.: PR -03