AMEC Earth & Environmental a division of AMEC Americas Limited 2227 Douglas Road, Burnaby, BC Canada V5C 5A9 Tel +1 (604) 294-3811 Fax +1 (604) 294-4664 www.amec.com Overall Geotechnical Report on the Pipeline Route Rev. R for the Enbridge Northern Gateway Project Bruderheim, Alberta to Kitimat, BC Submitted to: Northern Gateway Pipelines Inc. Calgary, Alberta Submitted by: AMEC Earth & Environmental, a division of AMEC Americas Limited Burnaby, BC September 9, 2009 Revised March 26, 2010 AMEC File: EG0926008 3001 Document Control No. 1123-RG-20100326 Northern Gateway Pipelines Inc. Overall Geotechnical Report Rev. R Bruderheim, Alberta to Kitimat, BC September 9, 2009 Revised March 26, 2010 TABLE OF CONTENTS Page 1.0 INTRODUCTION ............................................................................................................... 1 1.1 Purpose .................................................................................................................... 1 1.2 Project Overview ....................................................................................................... 1 1.3 Organization ............................................................................................................. 2 2.0 SETTING ........................................................................................................................... 4 2.1 General ..................................................................................................................... 4 2.2 Eastern Alberta Plains .............................................................................................. 4 2.2.1 Topography and Physiography ...................................................................... 4 2.2.2 Surficial Geology ........................................................................................... 5 2.2.3 Bedrock Geology ........................................................................................... 6 2.3 Southern Alberta Uplands ......................................................................................... 6 2.3.1 Topography and Physiography ...................................................................... 6 2.3.2 Surficial Geology ........................................................................................... 7 2.3.3 Bedrock Geology ........................................................................................... 7 2.4 Alberta Plateau ......................................................................................................... 9 2.4.1 Topography and Physiography ...................................................................... 9 2.4.2 Surficial Geology ........................................................................................... 9 2.4.3 Bedrock Geology ......................................................................................... 10 2.5 Rocky Mountains .................................................................................................... 10 2.5.1 Topography and Physiography .................................................................... 10 2.5.2 Surficial Geology ......................................................................................... 11 2.5.3 Bedrock Geology ......................................................................................... 12 2.6 Interior Plateau ....................................................................................................... 13 2.6.1 Topography and Physiography .................................................................... 13 2.6.2 Surficial Geology ......................................................................................... 14 2.6.3 Bedrock Geology ......................................................................................... 14 2.7 Coastal Mountains .................................................................................................. 15 2.7.1 Topography and Physiography .................................................................... 15 2.7.2 Surficial Deposits ......................................................................................... 16 2.7.2.1 General ......................................................................................... 16 2.7.2.2 Glaciomarine Clay ......................................................................... 18 2.7.3 Bedrock Geology ......................................................................................... 19 2.8 Regional Preglacial Valleys ..................................................................................... 20 3.0 GEOTECHNICAL CONSIDERATIONS ........................................................................... 21 3.1 General ................................................................................................................... 21 3.2 Natural Terrain Hazards .......................................................................................... 21 3.2.1 Mass Wasting .............................................................................................. 22 3.2.1.1 Deep-Seated Slides ...................................................................... 22 3.2.1.2 Shallow to Moderately Deep Slides ............................................... 22 3.2.1.3 Debris Flows ................................................................................. 23 3.2.1.4 Rockfall ......................................................................................... 24 3.2.1.5 Avalanches ................................................................................... 24 3.2.1.6 Mountain Spreading (Sackung) ..................................................... 24 AMEC File: EG0926008 3001 Page i P:\PROJECTS\Other Offices\EG-Edmonton\EG09260 - Enbridge Gateway\3001 - April 2006 NEB Report\Reports_Deliverables\Overall Geo\Reports\Rev R\March 2010\Rev R_Overall Geo Report_9Sept09_Revised_26MAR2010.doc Northern Gateway Pipelines Inc. Overall Geotechnical Report Rev. R Bruderheim, Alberta to Kitimat, BC September 9, 2009 Revised March 26, 2010 TABLE OF CONTENTS Page 3.2.1.7 Lateral Spreading .......................................................................... 25 3.2.1.8 Stream Erosion and Sedimentation ............................................... 25 3.2.1.9 Wind and Shallow Stream or Overland Erosion ............................. 26 3.2.2 Settlement.................................................................................................... 26 3.2.2.1 Consolidation Settlement ............................................................... 26 3.2.2.2 Karst-induced Settlement or Displacement .................................... 26 3.3 Seismic Conditions .................................................................................................. 26 3.3.1 Geologic Setting .......................................................................................... 26 3.3.2 Estimates of Ground Motion ......................................................................... 28 3.3.3 Natural Hazards Due to Seismic Events ...................................................... 29 3.4 Tsunamis ................................................................................................................. 31 3.4.1 Seismically Generated Tsunamis ................................................................. 31 3.4.2 Slide Generated Tsunamis in Kitimat Arm – Background ............................. 32 3.4.3 Conclusions and Comments ........................................................................ 33 3.5 Acid Rock Drainage and Metal Leaching ................................................................. 34 3.6 Watercourse Crossing Methods............................................................................... 35 3.7 Clore/Hoult Tunnels near Mount Nimbus ................................................................. 35 3.8 Rock Excavation ...................................................................................................... 36 3.9 Potential Borrow Sources ........................................................................................ 37 4.0 TERRAIN HAZARDS AND RISK ANALYSIS ................................................................... 38 4.1 General ................................................................................................................... 38 4.2 Qualitative Risk Overview Methodology ................................................................... 38 4.2.1 Overview ...................................................................................................... 38 4.2.2 Hazards ....................................................................................................... 39 4.2.3 Hazard Probabilities ..................................................................................... 39 4.2.4 Consequences ............................................................................................. 41 4.2.5 Risk Evaluation ............................................................................................ 42 4.2.6 Limitations of the Risk Assessment .............................................................. 42 4.3 Results of Risk Analysis .......................................................................................... 43 4.3.1 Overall Risks ................................................................................................ 43 5.0 GENERAL GEOTECHNICAL RECOMMENDATIONS ..................................................... 52 5.1 General ..................................................................................................................