Landfill Design and Operations Plan For Chemical Waste Management of the Northwest, Inc.

Arlington Facility • ORD 089 452 353 17629 Cedar Springs Lane Arlington, Oregon

Standalone Document No. 14

This document is issued by the Oregon Department of Environmental Quality

December 2015

Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

TABLE OF CONTENTS

1.0 INTRODUCTION ...... 1-1 1.1 Active/Proposed Landfills ...... 1-2 1.2 Closed Landfills ...... 1-2

2.0 ACTIVE LANDFILL DESIGN ...... 2-1 2.1 Landfills L-12 and L-13 Design ...... 2-1 2.1.1 Landfill L-12 and L-13 Foundations ...... 2-1 2.1.2 Landfill L-12 and L-13 Liner and Leachate Collection System Design .. 2-2 2.2 Landfill L-12 and L-13 Liner Specifications and Installation ...... 2-3 2.2.1 Synthetic Liners, Leachate Collection Systems and LCRS Collection Pipes ...... 2-3 2.2.2 Landfill L-12 and L-13 Soil Liner Subgrade and Soil Liners ...... 2-4 2.2.3 Closure of Landfill L-12 North Primary Leachate Collection System Vertical Access Riser ...... 2-6 2.3 Landfill L-14 Design ...... 2-6 2.3.1 General Configuration ...... 2-6 2.4 Landfill L-14 Foundation ...... 2-7 2.4.1 Foundation Settlement and Bearing Capacity ...... 2-7 2.5 Landfill L-14 Liner and Leachate Collection System Design ...... 2-8 2.5.1 Base Grade Configuration ...... 2-9 2.5.2 LCRS Geocomposite Flow Capacity ...... 2-9 2.5.3 Sump Riser Pipe Structural Integrity .... 2-10 2.5.4 Slope Stability - Intermediate Slopes .... 2-10 2.6 Landfill L-14 Liner Specifications and Installation .... 2-11 2.7 Landfill L-14 Final Cover .... 2-12 2.7.1 Final Cover Geocomposite Flow Capacity .... 2-12 2.7.2 Stability of Waste Mass and Final Cover .... 2-12 2.7.3 Final Cover Soil Erosion .... 2-12

3.0 LANDFILL OPERATIONS ...... 3-1 3.1 Waste Acceptance Procedures ...... 3-1 3.2 Fill Sequencing ...... 3-2 3.3 Control of Run-on and Run-off ...... 3-2 3.4 Construction Inspection of Landfills ...... 3-4 3.5 Final Cover ...... 3-4 3.6 Ignitable and Reactive Wastes ...... 3-4 3.7 Incompatible Wastes ...... 3-5 3.8 Control of Wind Dispersal of Wastes ...... 3-5 3.9 Disposal of Dioxin-Containing Wastes (i.e., F020, F021, F022, F023, F026, F027, and F028 ...... 3-6 3.9.1 Exposure Control Practices ...... 3-7 3.9.2 Waste Characteristics ...... 3-7 3.9.3 Disposal Procedures ...... 3-7

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TABLE OF CONTENTS (Cont.)

TABLES

1-1 Summary of Applicable Design and Construction Documents and Key Design Components 1-2 Summary of Size and Capacity of Closed Landfill Units 2-1 Summary of Landfill L-12 Design 2-2 Summary of Landfill L-13 Design 2-3 Summary of Landfill L-14 Design

FIGURES

1-2 Facility Process Flow Diagram

APPENDICES

A Calculations For Design of L-14

DEQ Issued ii Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

LANDFILL DESIGN AND OPERATIONS PLAN

1.0 INTRODUCTION

This Landfill Design and Operations Plan addresses existing landfill units and permitted but not yet built landfill cells at the Chemical Waste Management of the Northwest, Inc. (CWMNW) Arlington Facility. Locations of existing and proposed landfills are shown on Figure 1-1 Facility Layout Map (as contained in the Part B Permit). As shown on the figure, there are three active landfills (L-12, L-13, and L-14) and eight inactive landfills, which have been completely filled and closed in accordance with an approved closure plan (L-1, L-3, L-5, L-6, L-7, L-8, L-9, and L-10 -- shown shaded). Figure 1-1 Facility Layout Map (as contained in the Part B Permit) also shows the location of the proposed expanded footprint of Landfill L-14.

Landfill units at the Arlington Facility are used for the permanent disposal of solid hazardous and industrial wastes. On reaching final design grades, all landfills are covered by a final cover designed to minimize soil erosion and infiltration of rainwater through the final cover. Final cover design details for the currently active and future proposed landfills are presented in the facility’s Landfill Final Cover Design Plans document and in the document titled Alternative Final Cover Design Report, Landfills L-12, L-13 and L-14 (Revision 0, May 2012).

All types of commercial, industrial, and agricultural wastes, including those identified or listed as hazardous wastes in 40 CFR Part 261, are potential candidates for landfill disposal at the Arlington Facility. Wastes that are not accepted at the facility are listed in Part A (Attachment 3) of the Permit Renewal Application. In addition, bulk and containerized liquid wastes are not accepted for landfilling, unless:

The waste has been stabilized so that free liquids no longer are present;

The container is very small (such as an ampule) or is a lab pack; or

The container is designed to hold free liquids for use other than storage, such as a battery.

A process flow diagram that illustrates the movement of hazardous wastes into the landfills is shown on Figure 1-2. Waste analysis procedures, which dictate what wastes will be accepted for landfilling, are presented in the facility's Waste Analysis Plan.

In 2010 CWMNW completed a new estimate of needed disposal capacity, which resulted in the decision to expand the disposal capacity of Landfill L-14 from 3.1x106 cubic yards to 6.3x106 cubic yards.

All of the landfill units are located well above the saturated zone (i.e., the uppermost aquifer). A comprehensive description of the site geology/hydrogeology can be found in the following documents previously submitted to the Oregon Department of Environmental Quality (DEQ):

Geologic and Hydrogeologic Site Characterization Report, Part B Permit Application, prepared for Chem-Security Systems, Inc., by Dames and Moore, dated April, 1987;

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RCRA Facility Investigation Report for Landfill Units L-9 and L-10, prepared for Waste Management, Inc. (Arlington, Oregon), by CH2MHill and Rust Environment and Infrastructure, Inc., dated May 20, 1996; and

Hydrogeologic Investigation and Engineering Design Report for Landfill L-14, Arlington, Oregon, prepared for Chemical Waste Management of the Northwest, Inc., by Rust Environment and Infrastructure Inc., dated February, 1998.

The uppermost aquifer which may potentially be impacted as a result of the landfill activities is monitored in accordance with the facility’s Groundwater Monitoring Plan.

1.1 Active/Proposed Landfills

This Landfill Design and Operations Plan focuses on design features and landfill operational procedures for currently active and future landfill cells. Supporting geotechnical studies and engineering analyses performed as part of the landfill siting/design have been previously submitted to the DEQ prior to each landfill unit construction. Currently active landfill units were constructed in accordance with approved construction drawings and technical specifications prepared specifically for that phase of construction and include L-12, L-13, and Cells 1, 2 and 3 of L-14,. Additional cells of Landfill L-14 (Cells 4 and 5) will be constructed in accordance with the approved construction drawings and technical specifications, and construction quality assurance will be guided by project specific Construction Quality Assurance Plans prepared prior to initiating construction.

Applicable design and construction documents and key design components for the currently active landfills and the remaining unconstructed cells within Landfill L-14 are summarized in Table 1-1. The design and construction documents demonstrate compliance with 40 CFR 264.301 through 264.304, and have been previously submitted to the ODEQ. They are incorporated into this document by reference.

1.2 Closed Landfills

Eight landfill units (L-1, L-3, L-5, L-6, L-7, L-8, L-9, and L-10) have been closed, via placement of a final cover, in accordance with approved closure plan specifications at the time of closure. Table 1-2 summarizes the size and capacity of the closed landfill units. Copies of the closure certifications are included in Section 14.0 of the most recent Permit Renewal Application.

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1.3 Figure 1-2

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan

Landfill Design/ Construction Plans, Landfill L-12, Design Approval and Approval to See facility's Landfill Exceeds Minimum Technology L-12 Constru Dames & Moore, June 9, 1986. Construct Incorporated into Response Action Requirements for Landfills. ction Construction Technical RCRA Part B Permit ORD Plans document Composite Liner System. Specifications, incorporated into 089452353, Condition VI.B., LCRS/LCS and LCDRS/LDS RCRA Part B Permit ORD Attachment 23, and Attachment can be accessed through vertical 089452353, Attachments 19, 20, & 24, Exhibit 6B.(1) sumps and sideslope risers. 21, March 11, 1988 (1) 1996 Closure Cover Redesign Documentation of L-12 Riser includes steeper sideslopes and Decommissioning incorporates updated geosynthetic materials.

CQA Construction Certification Report, Landfill L-12 As-built Landfill L-12, Golder Associates, Certification, DEQ, May 12, Inc., 1995 1995.

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan

Closure Closure Cover Design Existing Closure Design Approval Active Landfills L-7, L-9, and L-10, Incorporated into RCRA Part B and Proposed Landfill L-12, Permit No. ORD 089452353; Arlington, OR, Golder Associates, Condition II.J., Condition VI.B., Inc., May, 1987. Attachment 8, and Attachment 9, Revised Closure Cover Design, Exhibit 20C.(1) Landfill L-12, Arlington, Oregon, Approval for final grades received Golder Associates, Inc., October 30, July 1, 1998. 1996. Approval for replacement of clayliner with GCL received from DEQ, May 21, 2001.

Landfill Design/ Request Approval to Construct Approval to Excavate, DEQ, See facility's Landfill Exceeds Minimum Technology L-13 Constru Landfill L-13, CSSI, August 6, 1984. August 8, 1984. Response Action Requirements for Landfills. ction Engineering Plans, Landfill L-13, Plans document Composite Liner System. Dames & Moore, September 25, LCRS/LCS and LDCRS/LDS 1984, CSSI submittal letter dated Revised Engineering Plan accessed through vertical September 27, 1985. Approval, Landfill L-13, ODEQ, sumps. Revised Engineering Plans, Landfill December 13, 1984. 1996 Closure Cover Redesign L-13, Dames & Moore, CSSI includes steeper sideslopes and submittal letter dated November 27, Design Change Approval, incorporates updated 1984 (change in size, addition of Landfill L-13, DEQ, April 15, geosynthetic materials.

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan protective soil cover). 1985. Revised Engineering Plans, Landfill L-13, Dames & Moore, CSSI 100 mil Liner Approval, Landfill submittal letter dated March 29, 1985 L-13, DEQ, September 26, 1985. (adds second HDPE liner, raises sw corner of L-13). Landfill L-13 Design Request to Modify Engineering Modification Approval, Plans, Landfill L-13, CSSI Letter September 8, 1986. dated May 23, 1985 (replaces protective soil with 100 mil sheet). Modification to Landfill Bottom, Landfill L-13, Dames & Moore, August, 1986, CSSI submittal letter Dated September 5, 1986 (adds another 60 mil HDPE primary liner system)

Landfill CQA Quality Assurance of the HDPE See facility's Landfill L-13 Liner System final Report, Response Action Plan Geoservices, Inc., November, 1985. document Certification Report, Slurry Trench Cut-off Wall Construction, Landfill Approval to use Landfill L-13,

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan L-13, Dames & Moore, December 5, Cells 1 and 2, DEQ, May 12, 1985. 1987. Construction Certification Report, Landfill L-13 Soil Liner, Dames & Moore, July 17, 1986 Construction Quality Assurance Approval to use Landfill L-13, Certification, Landfill L-13, CSSI Cells 3 and 5, DEQ, December Letter December 5, 1986 14, 1989. Construction Quality Assurance Certification, Landfill L-13 (Cells 1 Approval to use Landfill 13, Cell and 2), CSSI Letter January 5, 1987 4, DEQ, July 20, 1988. Primary Synthetic Liner, Sumps, Drainage Layer, and Working Approval to use Landfill 13, Cell Surface Layer Construction 6, DEQ, November 4, 1988. Certification Report, Landfill L-13, Cells 3 and 5, Golder Associates, October 2, 1989 Separator Berm and Secondary HDPE Liner Construction Certification Report, Landfill L-13, Cells 3 and 5, Golder Associates, October 30, 1989 Cell 4 Completion, Construction

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan QA/QC Report., Golder Associates, July 11, 1987 Primary Clay Liner Construction Certification Report, Landfill L-13, Cells 4 and 6, Golder Associates, September 15, 1988 Separator Berm and Secondary HDPE Liner Construction Certification Report, Landfill L-13, Cells 4 and 6, Golder Associates, September 15, 1988

Landfill Closure Revised Closure Cover Design, Landfill L-13 Closure Cap L-13 Landfill L-13, Arlington, Oregon, Redesign Approval, DEQ, Golder Associates, Inc., November, January 30, 1996. 1991 Closure Design Approval Waste Management Inc, Arlington Incorporated into RCRA Part B Hazardous Waste Facility, Landfill Permit No. ORD 089452353; L-13, Revised Closure Cover Design Condition II.J., Condition VI.A., No. 2, Golder Associates, August 17, Attachment 8, and Attachment 9, 1995 Exhibit 20C.(1) Approval for replacement of clay

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan liner with GCL received from DEQ, May 21, 2001.

Landfill Design/ Hydrogeologic Investigation and Outstanding modification See facility's Landfill Exceeds Minimum Technology L-14 Constru Engineering Report, Proposed submitted with Permit Renewal Response Action Plan Requirements for Landfills. ction/ Landfill L-14, Rust Environment & Application (March, 1998) document Utilizes Geosynthetic Clay CQA/ Infrastructure, February, 1998 Liner. Closure Third liner under leachate collection sumps. Landfill s L-12, Revised Closure Cover Design L-13, Report, Thiel Engineering, February Redesign to steepen sideslopes. and L- 2005 14 Cell 1 Construction Drawings and Landfill Technical Specifications, Earth Tech, L-14 Inc., April 2003 Cell 2 Construction Documents and Technical Specifications, Earth Tech, Inc., March 2005 Cell 3 Construction Drawings and Technical Specifications, Environmental Information

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Table 1-1

SUMMARY OF APPLICABLE DESIGN AND CONSTRUCTION DOCUMENTS AND KEY DESIGN COMPONENTS

Applicable Design and Construction Documents Description of Key Design Landfill Components Unit Phase Documents Approvals Response Action Plan Logistics, LLC, February 2010

See 2010 Part B Permit Modification modification to RAP Application, Environmental as it relates to the Exceeds Minimum Technology E Information Logistics, LLC, October secondary leachate Requirements for Landfills. 2011 ((THIS DOCUMENT)) collection and Expanded footprint of landfill removal system (SLCRS) Cell 1 Construction Report Cell 2 Construction Report Cell 3 Construction Report Notes: CSSI - Chem-Security Systems Incorporated CQA - Construction Quality Assurance LCRS/LCS - Leachate Collection and Removal System LDCRS/LDS- Leachate Detection, Collection, and Removal System DEQ - Oregon Department of Environmental Quality(1) - RCRA Part B Permit Effective March 11, 1988 through March 10, 1998

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Table 1-2

SUMMARY OF SIZE AND CAPACITY OF CLOSED LANDFILL UNITS

Landfill Unit Size/Capacity Operating Status Completely filled: July 15, 1981 L-1 60' x 500' x 25' (deep) Final closure cover: completed Completely filled: December 1, L-3 65' x500' x 32.5' (av. depth) 1981 Final closure cover: completed 160' x 350' x 34.5' (av.depth) (RCRA wastes) Completely filled: May 20, 1981 L-5 160' x 150' x 31.75' (av. depth) (non-RCRA Final closure cover: completed wastes) Completely filled: May 20, 1981 L-6 175' x 700' x 30' (av. depth) Final closure cover: completed 255' x 525' x 48' (deep) (RCRA wastes) 187' (av.) X 135' x 42' (deep) (non-RCRA Completely filled: 1990 L-7 wastes) Final closure cover: completed

Capacity 167 acre-feet (1) 120' x 600' x 30' (deep) (accepted potlining wastes) Completely filled: 1989 L-8 Final closure cover: completed Capacity 65 acre-feet (1) 200' x 400' x 50' (deep) (RCRA wastes) 200' x 200' x 40' (deep) (non-RCRA wastes) Completely filled: 1990 L-9 Final closure cover: completed Capacity 101 acre-feet (1) 400' x 600 x 66' (deep) Completely filled: 2002 L-10 Final closure cover: completed Capacity 362 acre-feet

Notes: (1) This is the total capacity of the landfill during its active life and included mounding of waste above grade. The capacity for non-RCRA waste is not included in this amount.

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2.0 ACTIVE LANDFILL DESIGN

Three landfill units are in use at the Arlington Facility, L-12, L-13, and L-14. These active landfills all received hazardous wastes after November 19, 1980 (the date when hazardous wastes were first regulated under RCRA). Detailed plans and specifications for construction of the active landfills are included in the facility’s Landfill Design Drawings document and/or project specific construction drawings and technical specifications. Pertinent design details are summarized in Tables 2-1 through 2-3.

2.1 Landfills L-12 and L-13 Design

Landfill L-13 was constructed prior to Landfill L-12. Both Landfill L-12 and L-13 are currently being used for landfill disposal.

Landfill L-13 is a single-phase unit, divided into six hydraulically separated cells. The total surface area of L-13 is approximately 17.6 acres. Landfill L-13 has a total design capacity of approximately 1,252 acre-feet (2.02x106 cubic yards).

Landfill L-12 is a single-phase unit, divided into two hydraulically separated cells. The total surface area of L-12 is approximately 9 acres. Landfill L-12 has a total design capacity of approximately 486 acre-feet (0.78x106 cubic yards).

2.1.1 Landfill L-12 and L-13 Foundations

Detailed engineering analyses were conducted as part of the L-12 and L-13 siting/design to evaluate settlement/heave, bearing capacity, cut slope stability under static and dynamic loading conditions, and liquefaction potential. The results of these evaluations and other analyses presented in this section have been previously submitted to the DEQ in the following document as part of the design/siting documents required for landfill construction approval:

Part B Permit Application, prepared for Chem-Security Systems, Inc., by Dames and Moore, dated 24 June, 1986 - Exhibits 7 and 19.

Foundation materials of L-12 and L-13 have relatively high strength and low compressibility characteristics. Since foundation grades at both landfills are well above (>100 feet) the groundwater table, most of the settlement/heave is elastic and will occur as the loads are applied or removed. Maximum heave was estimated to be in the range of 1 to 3 inches during landfill excavation. Net settlement after the landfills have been filled with waste is expected to be about 1 inch or less. The location of the groundwater table relative to the landfill foundation soils also precludes liquefaction of these soils.

Since the final loads on the foundation soils of the L-12 and L-13 after waste filling will be similar to the initial loads prior to the excavation, the foundation soils have an adequate factor of safety against local bearing failures. The foundation soils, which are hard/very dense, had sufficient strength to support the construction and operation equipment. Analysis also showed that the soil liner material has an adequate safety factor against local bearing failure.

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Sideslopes of Landfill L-12 and L-13 were excavated at a maximum slope of 3H:1V. Stability analyses of these excavation slopes show that the landfills have adequate factors of safety under both static and dynamic loading conditions. The bottom (floor) area of the landfill units have a minimum 2 percent slope that provides drainage for the upper (primary) and lower (secondary) leachate collection systems.

2.1.2 Landfill L-12 and L-13 Liner and Leachate Collection System Design

Liner systems for Landfills L-12, and L-13 were designed in accordance with EPA guidelines to prevent leachate migration. The system design consists of upper (primary) and lower (secondary) composite liners separated by two leachate collection systems. The primary leachate collection and removal system (LCRS or LCS), located above the upper liner, prevents the buildup of excessive hydraulic pressure head on the surface of the upper synthetic liner. A secondary leachate collection system (also referred to as the leachate [or leak] detection, collection, and removal system [LDCRS or LDS]), located between the upper and lower liners, provides for the rapid collection of any leachate in the unlikely event that a leak should develop in the upper liner.

The liner system (base and sideslope) for Landfill L-13 is summarized in Table 2-2. The design of Landfill L-12 was completed prior to waste filling in L-13. The Landfill L-12 design incorporated additional features to the liner design on the base of the landfill for improved liner performance. Based on the Landfill L-12 design, additional construction was completed in Landfill L-13 to implement the Landfill L-12 modifications. The liner system (base and sideslope) for Landfill L-12 is summarized in Table 2-1. The original base liner design of Landfill L-13 incorporated a double geomembrane/geonet system over a 3-foot thick soil/bentonite layer. The Landfill L-12 design incorporated an additional 1.5-foot thick soil/bentonite layer between the two geomembrane/geonet layers. Based on the incorporation of this additional soil/bentonite component into the Landfill L-12 design, it was decided to retrofit the Landfill L-13 liner to add the soil/bentonite component. The Landfill L-13 liner was reconstructed by removing 1-foot of the previously constructed 2-foot thick soil working layer (placed over the double geomembrane/geonet system), and then constructing a new 1.5-foot thick soil/bentonite layer overlain by a new (third) geomembrane/geonet layer.

The primary leachate collection systems of Landfills L-12 and L-13 consist of a synthetic drainage layer (geonet or geocomposite) overlain by a 1-foot thick granular drainage layer in the bottom of the landfills. A geotextile separates the drainage material from the gravel. Perforated HDPE collection pipes were placed along the bottom of the landfill cells to improve the efficiency of leachate collection and minimize the buildup of head on the upper liner. On the sideslopes, due to the 3H:1V gradient, a single layer of synthetic drainage material collects leachate.

A secondary leachate collection system consisting of a single layer of synthetic drainage material is installed between the upper and lower liners.

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Leachate from the primary and secondary collection systems is channeled toward primary and secondary leachate collection sumps, respectively, located on the landfill bottom within each cell. Each primary sump is equipped with a sideslope riser to permit convenient sampling and removal of leachate during the operational and post-closure periods. In addition, the south sump has a vertical riser that acts as an alternate route for leachate removal. A vertical riser connected to the north sump was abandoned in 2003. See Section 2.2.3. The secondary leachate collection sumps are equipped with single risers located on the sideslopes. The secondary risers are sandwiched between the upper and lower liners to eliminate penetration of the geomembrane liners.

Leachate is removed from the leachate removal sump (the primary sump) once leachate levels are near or above their respective action levels. The leachate is pumped either to a portable leachate storage container located within the footprint of the lined area of the respective landfill unit or directly to dust control sprinklers or drip systems. Leachate is removed with a vacuum truck, submersible pump or equivalent. The leachate is spread through a drip or sprinkler system onto the landfill surface to control fugitive dust emissions. Leachate volumes not needed for dust control are removed via a vacuum truck to the wastewater treatment plant or a surface waste impoundment for treatment or disposal, as appropriate.

Responses required to address liquids that accumulate in the secondary leachate collection sumps are presented in the facility’s Landfill Response Action Plans document.

Details of the liner, base materials, and leachate collection systems for Landfills L-12 and L-13 are presented in the facility’s Landfill Design Drawings document, and are summarized in Tables 2-1 and 2-2, respectively.

2.2 Landfill L-12 and L-13 Liner Specifications and Installation

The landfill liner systems for Landfills L-12 and L-13 were installed in accordance with approved construction drawings and technical specifications prepared for each unit prior to construction. Inspections were conducted during construction as described in Section 3.4of this document. Construction Quality Assurance (CQA) reports have been previously submitted to the DEQ (see Table 1-1) certifying that the currently active landfills were constructed in accordance with the approved technical specifications at the time of construction.

2.2.1 Synthetic Liners, Leachate Collection Systems and LCRS Collection Pipes

CWMNW uses HDPE 60-mil synthetic geomembrane liner material for hazardous waste landfills operated by the company. This material was chosen based on review of manufacturer's test data, submersion, physical testing, and prior operating experience. This information indicates that 60-mil HDPE has the best physical characteristics (particularly related to stress deformation, puncture resistance, and weatherability) and the widest range of compatibility with anticipated leachate that may be generated in landfill units at the Arlington Facility. This liner material can also be extrusion- or fusion-welded to produce stronger, more consistent seams than materials requiring solvent welding.

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To further confirm the compatibility of HDPE with the type of leachate that may be generated in landfills, CWMNW has completed a program conducted by polymer chemists to determine those chemical constituents that might impact synthetic liners and the possible concentrations of these constituents in leachate from a solids-only landfill. Submersion testing and physical testing of samples following exposures have also been completed. Welded liner seams made of the same HDPE material were also tested.

Maximum stresses under which components of the liner systems may be subjected were calculated. It has been demonstrated through laboratory tests and calculations that the stresses imposed on the liner systems will not exceed the yield point of the HDPE liners. Minimum specification for HDPE liner materials for L-12 and L-13 are summarized in the respective construction documents prepared for each landfill.

Calculations were also completed to demonstrate that waste loading on the leachate collection pipes would not cause them to deform. Collection pipes and drainage layers will not deform excessively under the imposed loading conditions.

A summary of test data, engineering analyses, and laboratory tests obtained to date regarding HDPE liners, which have been performed to demonstrate the function of the leachate collection systems, have been previously submitted to the DEQ in the following document: Part B Permit Application, prepared for Chem-Security Systems, Inc., by Dames and Moore, dated 24 June, 1986 - Exhibits 5 and 19.

2.2.2 Landfill L-12 and L-13 Soil Liner Subgrade and Soil Liners

In general, earthwork for constructing soil liner subgrade for existing landfill units L-12 and L- 13 included either soil cut or fill. For portions constructed on fill, subgrade was constructed in loose lifts of approximately 6 to 8 inches thick, with each lift compacted in accordance with the approved technical specifications.

For the portions constructed by cut, the upper 12 inches of the in-situ soil subgrade was scarified, moisture conditioned, and re-compacted in accordance with the approved technical specifications. The finished subgrade was prepared to be free of protrusions, irregularities, or discontinuities.

The prepared subgrade was covered with at least 3 feet of compacted low permeability soil liner material that had a maximum hydraulic conductivity of 1 x 10-7 cm/sec. The soil liner provided a firm and uniform base for the installation of the synthetic liner system.

The soil liner subgrade and soil liner were completed under the direction of a professional engineer implementing the approved CQA Plan. In-place soil moisture and dry densities were determined by the Nuclear Densometer Method (ASTM Tests D-2922-81 and D-3017-78) or the Sand Cone Method (ASTM Test D-1556-64) to verify that the soil liner subgrade and soil liner were compacted to meet specified soil moisture and density.

The soil liner was constructed of in-situ fine grained soils mixed with at least 5 percent bentonite by dry weight to obtain a maximum permeability of 1x10-7 cm/sec after compaction. The soil

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liner material was placed on a grade of approximately 3H:1V or flatter with no abrupt changes in grade. The soil liner material was free of rock, fractured stone, debris, cobbles, rubbish, lenses, cracks, channels, root holes or other structural non-conformities that could increase its hydraulic conductivity. The foundation provided by this compacted soil liner material which rests on naturally consolidated soils and compacted subgrade soils ensures the integrity of the liner and foundation of the landfill.

Based on various subsurface explorations and laboratory testing programs, the native clayey silt soils used to construct soil liner had the following typical characteristics:

Unified soil classification: ML/CL or MH/CH In situ moisture content: 62-99 percent (75 percent average) In situ dry density: 45-64 pcf (52 pcf average) Atterberg limits: 90 < LL < 120; 29 < PI < 68

Native fine-grained soils appropriate for use in preparation of the soil liner were visually inspected, segregated, and stockpiled under the direction of the Field Engineer. Additional soil index and classification tests were conducted, as necessary, to confirm the adequacy of the native soils for soil liner construction. To obtain the desired permeability, a minimum of 5 percent by dry weight of bentonite was added to the native clayey silt soils. The bentonite mixture was Custom Sealant 50 manufactured by the American Colloid Company or its equivalent, subject to approval by the Field Engineer. The bentonite spreading rate was adjusted at the time of soil liner construction, as required, to comply with the permeability specification.

The soil liner material was placed in lifts parallel to the final grade. Lifts did not exceed 6 inches in compacted depth. Care was taken to scarify, blend, and compact layers together such that weak zones or zones of high permeability did not exist within the completed soil liner. The final lift was smooth rolled to produce a smooth surface for placement of the 60 mil HDPE liner.

A series of laboratory tests were conducted to assess the potential for dispersion and piping due to the flow of liquids through the soil liner material. Tests were conducted on samples of in-place compacted soil liner material containing at least 5 percent by dry weight of bentonite. The tests consisted of a pinhole test, a crumb test, and a double hydrometer test. Test procedures and results have been previously submitted to the DEQ in the following document: Part B Permit Application, prepared for Chem-Security Systems, Inc., by Dames and Moore, dated 24 June, 1986 - Exhibit 7A.

Results indicated that the soil/bentonite mixture shows no dispersive characteristics and that the potential for piping is very low.

DEQ Issued 2-5 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

2.2.3 Closure of Landfill L-12 North Primary Leachate Collection System Vertical Access Riser

The vertical access riser for the north primary LCRS sump in Landfill L-12 was damaged in March 2003. Damage to the vertical standpipe caused waste materials to slough into the access riser and fill approximately 100 feet of the pipe from the base of the sump. Since there are two riser pipes (one vertical and one along the eastern sideslope) that allow access to the LCRS sump in Landfill L-12, the vertical standpipe was closed and abandoned in place.

Procedures used for the abandonment of the vertical standpipe for the north primary LCRS sump in Landfill L-12 were outlined in the document entitled Decommissioning Plan for the Vertical Access Riser in Landfill L-12 North Primary Leachate Collection Sump.

2.3 Landfill L-14 Design

2.3.1 General Configuration

Landfill L-14 was originally designed as a multi-phase unit divided into four hydraulically separated cells. The 2013 expansion of Landfill L-14 added a fifth hydraulically separated cell to the landfill. Cell 5 is located north of Cells 1 – 4. The currently permitted planar area of L-14 is 35.5 acres. The currently permitted design of Landfill L-14 has a total design capacity of approximately 3,900 acre-feet (6.3x106 cubic yards). Supporting geotechnical studies and engineering analyses performed in support of the currently permitted landfill siting/design have been previously submitted to the DEQ in the following document:

Hydrogeologic Investigation and Engineering Design Report for Landfill L-14, Arlington, Oregon, prepared for Chemical Waste Management of the Northwest, Inc., by Rust Environment and Infrastructure Inc., dated February, 1998 - Section 8.0 and Appendix G.

The overall design concept for L-14 remains similar to previously constructed landfill units at the Arlington Facility in that the design meets or exceeds the minimum technology requirements for landfill units. General design details for the currently permitted Landfill L-14 are summarized in Table 2-3.

Cells 1 through 3 of Landfill L-14 were constructed as originally designed in 2003, 2005, and 2010-2011 respectively.

The expansion of Landfill L-14 also resulted in the need to revise the site’s surface water management system, because the expanded footprint encroaches into the existing surface water management impoundment (Pond B-2) located directly north of L-14, and some of the surface water conveyance systems, such as surface water conveyance ditches around the new footprint of L-14. Details of the revised surface water management system are provided in the revised Surface Water Management Plan (Standalone Document No. 6). Standalone Document 6 has been removed from the Part B permit.

DEQ Issued 2-6 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

2.4 Landfill L-14 Foundation

Detailed engineering analyses were conducted as part of the original L-14 siting/design to evaluate settlement/heave, bearing capacity, and cut slope stability under static and dynamic loading conditions. The results of these evaluations and other analyses presented in this section have been previously submitted to the DEQ in the following document as part of the design/siting documents required for landfill construction approval:

Hydrogeologic Investigation and Engineering Design Report for Landfill L-14, Arlington, Oregon, prepared for Chemical Waste Management of the Northwest, Inc., by Rust Environment and Infrastructure Inc., dated February, 1998.

2.4.1 Foundation Settlement and Bearing Capacity

Soils beneath L-14 have relatively high strength and low compressibility characteristics. Since the landfill’s foundation grades are well above (>100 feet) the groundwater table, most of the anticipated settlement is elastic and will occur as the loads are applied.

Settlement of the soils underlying the landfill (and of the soil/bentonite component of the base liner system, for Cells 1 – 3) was evaluated along a select leachate flowline within each of the five cells. Loads for each cell were calculated based on the proposed final grades of the expanded landfill.

For the five sections analyzed, the base grade slopes on the floor of L-14 meet the requirement of 40 CFR § 264.301(c)(3)(i) to be constructed at a minimum slope of 1%. Conservative estimates of post-settlement slopes show that all sections will maintain positive drainage.

Bearing capacity of the landfill was also re-evaluated to ensure that the base of the landfill would remain stable under the increased load resulting from the landfill expansion. The bearing capacity of the soils underlying the landfill was evaluated assuming that general shear failure will control since the landfill is a relatively non-rigid foundation on the subgrade soils.

Two scenarios were evaluated that cover the range of possible failure conditions. Both scenarios used long term or drained soil strength and assume the landfill is at the maximum height. A third scenario that used undrained or short term soil strength was considered but not evaluated because rapid soil loading conditions that induce undrained conditions in the soil have not occurred as the existing landfill has been filled, nor are they anticipated as part of the landfill development from expansion.

Maximum allowable waste heights were calculated under the two design scenarios and were 415 feet and 430 feet, versus the design height of 208 feet. Therefore, the soil underlying Landfill L-14 has sufficient bearing capacity to support the expanded landfill under the design conditions.

Since there are no soils at the site susceptible to earthquake induced liquefaction and the static factor of safety is high, separate calculations for earthquake loading were not performed.

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2.5 Landfill L-14 Liner and Leachate Collection System Design

The liner system for Landfill L-14 was designed in accordance with applicable regulations and EPA guidance. The liner system is similar to those of Landfills L-12 and L-13, however several key enhancements have been made:

Tertiary Sump – Each cell within L-14 has a tertiary sump constructed beneath the primary and secondary leachate collection sump system. The tertiary sump acts as an “engineered vadose zone” in an area of the landfill with the highest likelihood of a potential release (i.e., leachate collection sumps). The tertiary sumps are designed to provide the landfill unit with the earliest possible indication of a release that can be effectively monitored.

Incorporation of Geosynthetic Clay Liner – The liner system in all cells of L-14 utilizes a geosynthetic clay liner (GCL) in the upper composite (primary) liner, instead of the soil/bentonite liner used in Landfills L-12 and L-13. For Cells 4 and 5, Resistex plus GCL will also be used in the construction of the lower composite (secondary) liner as a replacement for the compacted soil/bentonite layer because of the lower permeability of the Resistex Plus GCL. An equivalency evaluation was conducted as part of the original Landfill L-14 permitting in 1998. It was not revised as part of this update because the design conditions have not changed. The original evaluation determined that the flux of water through the soil/bentonite liner was approximately 2.7 times greater than that for a GCL. This, along with other factors (scarcity of soil materials for soil liner, favorable weather conditions, production quality, cost, installation, repairs etc.), makes the GCL a suitable replacement to the soil/bentonite layer and will further reduce the possibility of a release from Landfill L-14.

The liner system (base and sideslope) for Landfill L-14 is summarized in Table 2-3.

Within each cell, leachate from the primary and secondary collection systems is channeled toward primary and secondary leachate collection sumps, respectively, located on the landfill bottom. Each primary sump in Cells 1 – 3 is equipped with a sideslope riser to permit sampling and removal of leachate during the operational and post closure periods. Cells 4 and 5 have two primary sideslope risers to provide additional access for pumps and other equipment. In addition, Cells 4 and 5 include a smaller diameter monitoring conduit. This pipe is located along the spine of the herringbone pattern of the base grades, runs through the primary leachate collection sump, and up the sideslope (adjacent to the primary sump risers) to daylight at the landfill perimeter. The pipe is perforated along the floor of each cell, and non-perforated on the sideslope.

The secondary leachate collection sumps are also equipped with a single riser for each cell located on the sideslopes. The secondary risers are sandwiched between the upper and lower liners to eliminate penetration of the geomembrane liners.

Equipment which has been approved for sampling monitoring wells pursuant to the RCRA Permit is used for sampling leachate from the secondary leachate collection sumps, if the

DEQ Issued 2-8 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan sampling is being performed to make a determination of whether the liquid is derived from hazardous waste.

Leachate is removed from the primary leachate removal sump when leachate levels are near or above the action level. The leachate is pumped to a vacuum truck and used for dust control within the landfill or transported to the on-site wastewater treatment plant for treatment.

Responses required to address liquids which accumulate in the secondary leachate collection sumps are presented in the facility’s Landfill Response Action Plans (RAP) document. The RAP was updated to reflect the changed design conditions due to expansion of the landfill. Responses required to address liquids which accumulate in the tertiary sump are presented in the facility’s Groundwater Monitoring Plan.

2.5.1 Base Grade Configuration

The floors of Cells 1 through 3 are planar and slope between 1 and 1.5 percent, from north to south toward a collection sump located along the southern edge of each cell. The base of Cell 4 also slopes from north to south but in a herringbone configuration with a sump at the toe of the southern sideslope. The floor of Cell 5 is also configured in a herringbone pattern, but slopes at 2.0 percent toward the spine of the herringbone, and then to a sump at the toe of the northern sideslope. Cells 1 through 3 and Cell 5 each have a shallow trench at the toe of the sideslope that directs liquids to that cell’s sump. Due to the shape of and the herringbone configuration of Cell 4, a toe trench is not necessary. The lined sideslopes of the landfill are at a 3:1 (H:V) slope.

Each cell is hydraulically separated from adjacent cells by an intercell berm. Each berm is three feet high (minimum) and is incorporated into the liner and leachate collection system.

2.5.2 LCRS Geocomposite Flow Capacity

The geocomposite layer of the primary leachate collection system was designed to remain free- draining under the maximum expected impingement rate. A design method was utilized that has been developed and refined over a number of years by several organizations within the geosynthetics industry, and is the industry standard for evaluating flow performance of geonets and geocomposites. The method accounts for various mechanisms that can impact the transmissivity of a drainage layer over time. These include: clogging due to biological and chemical activity, clogging due to sediment, and creep of the HDPE ribs of the geonet material. Conservative safety factors were used to account for all of these mechanisms in the analysis.

Calculations were performed for several scenarios using the maximum impingement rates from the HELP modeling performed as part of the 1998 permitting. Critical flow lines were analyzed for each cell to ensure that the geocomposite had sufficient flow capacity under the design impingement rate. The calculations document that a geocomposite in Cells 1 through 3 will perform satisfactorily under the loading imposed by the design waste thickness. A minimum required transmissivity was calculated for Cells 4 and 5 which will be used when specifying material for the construction of those cells.

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2.5.3 Sump Riser Pipe Structural Integrity

The structural integrity of the sump riser pipes were evaluated based on the design waste thickness. These calculations were prepared for the original L-14 design. The expansion of the landfill did not increase the design waste thickness above the sump riser pipes, so no design modifications were required for Cells 1 – 3. For Cells 4 and 5, the diameter of the sump riser pipes was increased from 18 to 24 inches. The updated calculations for Cells 4 and 5 demonstrate that the 24-inch diameter riser pipes satisfy the established factor of safety for structural integrity.

2.5.4 Slope Stability - Intermediate Slopes

Slope stability and foundation analyses were performed to document that the design grades of Landfill L-14 meets the regulatory requirements. Analyses were performed to model conditions during construction and operation of the landfill as well as after closure of the landfill. The analyses demonstrate that landfill slopes will be stable within the target factor of safety under the design conditions over the life of the landfill and throughout the post-closure period.

Slope Stability Evaluation Methods

The stability of the landfill slopes was evaluated using the limit equilibrium method. In general terms, this method is based on balancing translational and rotational forces of a waste mass sliding along a slip surface. Forces (moments or stresses) resisting instability (resisting forces) of the mass are balanced against those that cause instability (disturbing or driving forces).

Based on industry experience and an analysis of the shear strength of the various materials, it can safely be assumed that the weakest and therefore critical material in the landfill stability is one of the interfaces within the base liner system. The soils beneath the liner system and the waste are stronger than either liner system interface with those materials. Therefore, the calculations were performed to determine the lowest allowable interface strength of the liner system that meets the established minimum factors of safety.

Interface Friction Angles and Shear Strength

Shear strength data for the base liner system of Cells 1 through 3 was taken from testing performed as part of the detailed design of Cell 3 in 2010. Since the liner system of Cells 1 through 3 are identical and similar materials were used throughout, this is representative.

For future Cells 4 and 5, shear strength data from testing performed on the lining system in 2013 was used in the stability analyses. The lining system included the incorporation of GCL as a replacement for the soil/bentonite layer. Representative geosynthetic and soil materials were used in the testing. Cell-specific testing can be performed prior to the construction of Cells 4 and 5 to confirm that the strength envelope of the proposed materials meets the requirements established by this analysis.

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Static and Seismic Analysis Parameters

Analyses were performed for static and seismic conditions. Seismic conditions were assessed using a pseudo-static approach where a horizontal force equal to the peak design earthquake acceleration is applied to the waste mass.

A peak ground acceleration of 0.1819g was chosen for the seismic analysis. For the site location, this is the value that has a 2 percent chance of being exceeded in 50 years or a 10% chance of being exceeded in 250 years. The value was obtained from 2009-10 update of the Interactive Deaggregation of the USGS National Seismic Hazard Mapping Project.

Stability of Intermediate Grade Slopes

Conservative configurations of intermediate waste slopes were analyzed for the current landfill configuration as well as anticipated future filling patterns. The most critical section for the intermediate filling conditions was assessed to be a north-south section through Cells 4 and 5. It represents the point at which Cells 1 through 4 are filled to their interim capacity and Cell 5 is excavated but has no waste in place. Note that, as described in Section 3.2, the current cell development sequence plan calls for Cell 5 to be constructed before Cell 4, however the section analyzed is the most critical, therefore, it is used in the analysis.

The section was analyzed under both static and seismic conditions using conservative assumptions for waste strength, liner and final cover system strength, and earthquake forces. The analyses indicate that the stability of the proposed intermediate filling plans meet the established minimum factors of safety.

2.6 Landfill L-14 Liner Specifications and Installation

The landfill liner systems for the existing cells of Landfill L-14 have been installed in accordance with previously approved versions of this Landfill Design and Operations Plan, as well as approved construction drawings and technical specifications prepared for each cell prior to construction. Quality assurance was conducted during construction as described in Section 3.4 of this document. Construction Quality Assurance (CQA) reports have been previously submitted to the DEQ (see Table 1-1) certifying that the currently active landfills were constructed in accordance with the approved technical specifications at the time of construction.

Construction of Landfill L-14 cells 1 through 3 was completed in accordance with construction plans in Standalone Document No. 18 Landfill Design Drawings, and construction drawings and technical specifications submitted to the Department. Construction inspection of L-14 Cells 1 through 3 was completed in accordance with approved facility Construction Quality Assurance Plan (Construction Quality Assurance Plan for CWMNW, Inc., Standalone Document No. 16).

Future cells 4 and 5 will be constructed and inspected in accordance with construction drawings, technical specifications, and quality assurance manuals prepared and approved for each cell.

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2.7 Landfill L-14 Final Cover

Final cover systems that will be constructed in Landfill L-14 at closure are presented in the following facility documents: Landfill Final Cover Design Plans and Alternative Final Cover Design Report, Landfills L-12,L-13 and L-14 (Revision 0, May 2012).

Landfill closure procedures and post-closure maintenance of the landfill cover are described in the facility's Closure/Post-Closure Plans.

2.7.1 Final Cover Geocomposite Flow Capacity

The geocomposite layer of the final cover was designed to remain free-draining under the maximum expected impingement rate. The design method used was the same as the method used for the LCRS geocomposite described in Section 2.5.2

Calculations were performed for a conservative design scenario which uses the maximum proposed slope length as well as the maximum impingement rates from the HELP modeling performed as part of the 1998 permitting. A minimum required transmissivity was calculated for the geocomposite which will be used when specifying material for the construction of those cells.

2.7.2 Stability of Waste Mass and Final Cover

The stability of the landfill at final grade was also evaluated. The critical section is a north-south line through Cells 3 and 5 which passes through the thickest parts of the landfill, and has the longest and steepest slopes with the smallest buttresses. The section was analyzed under both static and seismic conditions using conservative assumptions for waste strength, liner and final cover system strength, and earthquake forces. The analyses indicate that the stability of the proposed final grading plan meet the established minimum factors of safety.

2.7.3 Final Cover Soil Erosion

The potential erosion of the upper soil layers of the final cover was evaluated to ensure that the cover will continue to perform as intended over the design period. Software developed by the U.S Department of Agriculture, Natural Resources Conservation Service was used to calculate a rate of soil erosion based on factors such as slope length, steepness, soil types, vegetative coverage, and type of vegetation.

Two scenarios were evaluate: (1) unvegetated slopes, which represents a short-term condition just after final cover construction is completed but before vegetation is established; and (2) vegetated slopes which represent the long-term scenario once vegetation has become established. The predicted soil loss rates calculated by the software for the short term condition indicate that some form of erosion protection may be required on the sideslopes (diversion berms, erosion blankets, etc.) until vegetation is established. For the long-term scenario with established vegetation, predicted soil loss rates are substantially less than the established maximum

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TABLE 2-1

SUMMARY OF LANDFILL L-12 DESIGN

Landfill Liner System Design Sideslope Design Leachate Final Cover Approximate Landfill Units (top to bottom) (top to bottom) Collection Sumps Design Design Capacity/Size (Total)

L-12 Upper (Primary) Leachate 100-mil HPDE Two primary and See facility's Size: 900' x 440' x 54' Cells 1 Collection System protective secondary Landfill Final (equiv.) and 2 Geotextile filter membrane leachate Cover Design Capacity: 486 acre-feet 1-ft granular drain Geotextile filter collection sumps Plans (Approx. 0.78 x 106 cubic Geotextile filter Geonet systems are document yards) Geonet (single synthetic 60-mil HPDE liner associated with drainage layer) Geonet Landfill L-12. 60-mil HPDE liner One sump system Composite Upper Minimum 3-ft is located within (Primary) Liner soil/bentonite each cell 60-mil HPDE liner liner Minimum 1.5-ft (permeability soil/bentonite liner 1x10-7 cm/sec or (permeability less) 1x10-7 cm/sec or less)

Lower (Secondary) Leachate Collection System Geotextile filter Geonet (single synthetic drainage layer)

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Composite Lower (Secondary) Liner 60-mil HPDE liner Minimum 3-ft soil/bentonite liner (permeability 1x10-7 cm/sec or less)

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TABLE 2-2

SUMMARY OF LANDFILL L-13 DESIGN

Landfill Liner System Design Sideslope Design Leachate Final Cover Approximate Landfill Units (top to bottom) (top to bottom) Collection Sumps Design Design Size/Capacity (Total) Original design modified to include an L-13 additional liner system Design modified to Six primary and See facility's Size: 850' x 900' x 71' Cells 1 – replace soil protective secondary leachate Landfill Final (equiv.) 6 Additional Upper (Primary) Leachate layer with 100-mil collection sumps Cover Design Capacity: 1,252 acre-feet Collection System HDPE protective layer systems are Plans (Approx. 2.02 x 106 Geotextile filter associated with document cubic yards) 1-ft granular drain Geotextile filter Landfill L-13. One Geotextile filter 100-mil HPDE sump system is Geonet (single synthetic drainage protective located within each layer) membrane cell Geotextile filter Additional Composite Upper Geonet (Primary) Liner 60-mil HPDE liner 60-mil HDPE liner Geonet Minimum 1.5-ft soil/bentonite liner 60-mil HPDE liner (permeability 1x10-7 cm/sec or Minimum 3-ft less) soil/bentonite liner Original Working Surface (permeability Typically 1-ft working surface 1x10-7 cm/sec or less) Original Upper (Primary) Leachate Collection System Geotextile filter Geonet (single synthetic drainage layer)

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Original Upper (Primary) Liner 60-mil HDPE liner

Original Lower (Secondary) Leachate Collection System Geonet (single synthetic drainage layer) drainage layer)

Composite Lower (Secondary) Liner 60-mil HPDE liner Minimum 3-ft soil/bentonite liner (permeability 1x10-7 cm/sec or less)

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TABLE 2-3

SUMMARY OF LANDFILL L-14 DESIGN

Landfill Liner System Design Sideslope Design Leachate Final Approximate Landfill Units (top to bottom) (top to bottom) Collection Sumps Cover Design Size/Capacity Design L-14 Upper (Primary) Leachate 12-inches granular drain Five primary and See Size: 1,260' x 1,280' x Cells 1- Collection System Protective membrane secondary leachate facility's 104 3 18-inches protective soil (option to be collection sumps Landfill Capacity: 3,900 acre-feet Geocomposite removed or left in- systems are Final (Approx. 6.3 x 106 cubic drainage layer place) associated with Cover yards) Geocomposite drainage Landfill L-14. One Design Composite Upper (Primary) layer sump system is Plans Liner 60-mil HPDE liner located within each document 60-mil HPDE liner Geocomposite drainage cell Geosynthetic Clay Liner layer (GCL) 60-mil HPDE liner Minimum 3-ft Lower (Secondary) soil/bentonite liner Leachate Collection System (permeability Geocomposite drainage 1x10-7 cm/sec or layer less)

Composite Lower (Secondary) Liner 60-mil HPDE liner Minimum 3-ft soil/bentonite liner (permeability 1x10-7 cm/sec or less) Cells 4- Resistex Plus GCL 5 DEQ Issued Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

3.0 LANDFILL OPERATIONS

3.1 Waste Acceptance Procedures

Each load of containerized waste received at the Arlington Facility is analyzed in accordance with the facility’s Waste Analysis Plan. If the waste is found to be acceptable the load is sent directly to the landfill, unless weather or operating conditions dictate otherwise (in which case the load is delivered to an appropriate storage area, provided the wastes are compatible). Containers are delivered to the landfill for disposal via both off-site and on-site trucks, and placed in rows immediately adjacent to each other.

Containers of bulk solid waste material (i.e., wastes having no free liquids) must be at least 90 percent full prior to placement in the landfill. CWMNW personnel have the option of rejecting the load (see Waste Acceptance Plan, Standalone Document #1), or filling the containers to the maximum extent possible prior to disposal in the landfill.

The only containers with free liquids that are landfilled are very small containers (i.e., ampules), containers of hazardous waste in overpacked drums (i.e., lab packs), and containers designed to hold free liquids for use other than storage (i.e., batteries). Each lab pack (as defined by U.S. Department of Transportation [DOT] hazardous materials regulations [40 CFR Parts 173, 178, and 179]) must be certified by the generator or packer (through the manifest system and prior approval and instructions from CWMNW) that:

Hazardous wastes are packaged in non-leaking inside containers;

Inside containers are of a sufficient design and constructed of a material that will not dangerously react, decompose, or ignite with the contained waste;

Inside containers are sealed tightly and securely;

The solidification material within the lab pack is compatible with the contained wastes and will not react, ignite, or decompose on contact with the wastes;

Incompatible wastes are not placed in the same lab pack; and

Containers of reactive wastes other than cyanide or sulfide bearing wastes are not placed in the lab packs, unless they have been previously treated or rendered non-reactive.

Liquids that are contained in lab packs, small containers, ampules, or batteries may be disposed without stabilization and related testing and verification procedures, provided other restrictions specified in the RCRA Permit or by other laws or regulations, do not prohibit the land disposal of such wastes.

The Arlington Facility does not dispose of any waste which is generated as a liquid and subsequently stabilized by the generator (or another off-site treatment facility) unless CWMNW

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The Arlington Facility does not dispose of any waste which is restricted from land disposal under 40 CFR Part 268 unless the applicable treatment standards as specified in 40 CFR Part 268 have been achieved or an approved treatment variance has been received. In addition, as new wastes are specified for land disposal restriction under 40 CFR Part 268, CWMNW immediately discontinue disposing of such wastes upon the effective date of the 40 CFR Part 268 regulation, unless the treatment standard as specified in 40 CFR Part 268 has been achieved or an approved treatment variance has been received. CWMNW will accept any Corrective Action Management Units (CAMU)-eligible waste which is in compliance with the requirements contained in 40 CFR 264.555. Prior to placement of CaMU-eligible wastes by the Arlington Facility, the Oregon Department of Environmental Quality must not object to its placement.

3.2 Fill Sequencing

Wastes are placed in the landfill in a series of lifts, with each lift consisting of either a single or double layer of waste material. If containers are part of the disposal material, they are placed in the lower layer; the upper layer consists of bulk waste materials.

The filling sequence for the landfill units starts at the bottom of one cell of the landfill and moves through a series of lifts toward the landfill top, as shown schematically on Figure 3-1. The depth of the lifts will vary, depending on the material being landfilled.

Access to the working face within each landfill is over temporary haul roads constructed on covered, filled waste material. As filling progresses, a terraced embankment is developed, with the highest point near the outer edges (sides) of the landfill. As each lift is completed, the temporary haul road is extended to the next lift. When the capacity of this stage of the landfill is reached, a new series of lifts are placed beginning with the lowest lift and filling upwards and back against the previously filled lifts. The former haul road is filled as each new lift begins.

Landfill L-14 is designed as a multi-phase landfill consisting of five hydraulically separated cells. This multi-phase design allows CWMNW flexibility with respect to operational considerations, predicted landfill disposal capacity requirements and closure. Based on current operational and infrastructure needs, CWMNW intends to construct the western portion of the Cell 5 next (designated Cell 5 West). This will be followed by development of the eastern portion of Cell 5 (designated Cell 5 East), and lastly Cell 4 in the southeast quadrant of Landfill L-14. However, if operational and infrastructure needs change, other fill sequences may be implemented at CWMNW’s discretion.

3.3 Control of Run-on and Run-off

The run-on prevention system at the Arlington Facility is typical for an arid climate, where the annual average rainfall is less than 10 inches and a high intensity rainfall event such as the 25-year, 24-hour storm would produce only 1.8 inches of rain. Details of the run-on and run-off control features are presented in the facility’s Surface Water Management Plan. Standalone Document 6 Surface Water Management Plan has been removed from the Part B permit.

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A series of ditches constructed around the perimeter of the landfills route run-on to one of two on-site surface water basins (see Figure 1-1 Facility Layout Map contained in the Part B Permit), where the water will be evaporated. The ditches are typically triangular, unlined earthen channels with 2H:1V sideslopes. The ditches are sized to convey the 25-year, 24-hour storm event and are designed with freeboard that will allow them to carry at least two times the design flow. Calculations performed as part of the surface water analysis indicate that the freeboard will allow the ditches to handle the 100-year, 24-hour storm event without overtopping,.

The berms and run-on ditches are inspected regularly, and after significant rainfall events in accordance with the facility’s Inspection Plan. Signs of deterioration, clogging, or failure are reported and appropriate repair actions, involving standard soil placement and compaction techniques, are taken to effect the necessary repairs.

In order to prevent discharge of run-off from the landfills surface onto the adjacent ground during each phase of operation, the following plan is implemented. For the period of time during which waste elevations are below surrounding grade, precipitation is contained within the landfill by the lined sideslopes. During this phase of operation, no run-off can discharge onto the adjacent ground. Any precipitation falling inside the perimeter of the active cells of the landfill is directed to temporary, geomembrane-lined surface water basins within the Landfill L-14 footprint.

The temporary detention basins are located in each cell between the toe of the waste slope and the cell divider berms, or immediately adjacent to each cell. Each area is lined with a geomembrane to prevent infiltration into the waste. The basins are sized to contain run-off from a 25-year, 24─hour storm.

Liquid collected in the temporary basins is removed by vacuum trucks or portable pumps maintained and operated by site personnel, and routed to the facility’s surface waste impoundments. Precipitation run-off is tested for toxicity in accordance with the procedures established in the facility’s Waste Analysis Plan and the exclusion in 40 CFR § 261.3(c)(2)(i), and then treated or discharged directly as appropriate.

Once waste elevations within the landfill are above the adjacent perimeter grade, and prior to constructing final cover, precipitation falling on the outer slopes of the landfill is directed to a channel formed by the toe of the slope and the liner, which directs flow to a basin. A berm is maintained around the perimeter of the landfill to prevent overflow.

Precipitation that falls on the landfill areas with final cover in place or into cells that do not contain waste is considered uncontaminated and is discharged without testing. After final cover is in place, no contaminated run-off is allowed to flow onto the adjacent covered areas. No contaminated vehicles are allowed to operate on the final cover, and incident precipitation is directed away from these areas.

Run-off from active slope areas could flow downslope over previously covered areas during placement of subsequent lifts of waste. To prevent this from occurring, a channel is maintained along the toe of the exposed waste slope, adjacent to the cover of the previous lift. All run-off

DEQ Issued 3-3 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

from the active slope areas is collected in the channel, which has the capacity to contain a 25-year, 24-hour storm. To minimize this occurrence, cover is placed over the active areas of the slope as soon as practical.

3.4 Construction Inspection of Landfills

During construction of new landfills, an independent Construction Quality Assurance firm is on-site to monitor and inspect material quality and installation of the materials for compliance with approved construction drawings and technical specifications.

Detailed construction quality assurance procedures are contained in the facility’s Construction Quality Assurance Plan and project specific construction quality assurance manuals. Upon completion of landfill construction activities a CQA report is prepared by the independent engineering firm certifying that the landfill was constructed in accordance with the approved construction drawings and technical specifications.

Inspections are conducted during installation of all components of the landfill liners, leachate collection and removal systems, and protective soil and geosynthetic layers. Geomembrane liners and covers are inspected during construction and/or installation for uniformity, damage, proper seaming, and imperfections. Upon completion of installation, the geomembranes are inspected and tested to verify seam integrity, and to verify there are no tears, punctures or blisters. Other routine landfill inspection procedures are described in the facility's Inspection Plan.

3.5 Final Cover

Final cover systems that will be constructed after waste reaches final design grades are presented in the following facility documents: Landfill Final Cover Design Plans and Alternative Final Cover Design Report, Landfills L-12, L-13 and L-14. Landfill closure procedures and post- closure maintenance of the landfill cover are described in the facility's Closure/Post-Closure Plans.

3.6 Ignitable and Reactive Wastes

Reactive wastes, as defined by RCRA, are not to be landfilled prior to undergoing approved treatment. All bulk ignitable and reactive wastes accepted by the facility for storage, treatment, and/or disposal are processed to a level such that the resulting material(s) no longer meet(s) the definition of an ignitable or reactive waste under 40 CFR § 261.21 or 261.23. The resulting material(s) are analyzed per the facility’s Waste Analysis Plan to verify that they are not ignitable or reactive wastes prior to final disposal in the landfill. Containerized solid ignitable wastes are landfilled in compliance with 40 CFR § 264.312(b) including the application of a daily cover of non-combustible wastes or inert soils.

DEQ Issued 3-4 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

3.7 Incompatible Wastes

Wastes placed in the landfills are assigned to one of three categories (combustibles, TSCA PCBs, and toxics) as a result of testing in accordance with the facility’s Waste Analysis Plan. The Hazardous Waste Compatibility Chart (EPA Document 600/2-80-076) is also used to ensure that no incompatible wastes are grouped in the same category.

The wastes are assigned to a specific area or cell of the landfill based on the classification. The location of each waste load is recorded according to a three dimensional grid system. Site landfill disposal procedures specify that inert material or neutral wastes are used to segregate cells and prevent the mixing of potentially incompatible wastes.

3.8 Control of Wind Dispersal of Wastes

Potential sources of fugitive dust emissions are: 1) earthmoving activities, such as excavation and transport of material for daily cover, 2) unvegetated active areas of the landfill, such as partially completed final covers or partially excavated trenches, 3) truck traffic on haul roads and ramps, 4) waste unloading operations in the landfills, and 5) exposed waste surface in the landfills.

Fugitive dust can be a problem at the Arlington Facility because of the semi-arid climate and persistent winds. The wind is usually from the west at about 5 to 10 miles per hour (mph); however, there are occasional gusts of 20 to 40 mph. Control of fugitive dust at the landfill is accomplished by surface application of leachate. Leachate is pumped from the leachate detection sumps in an individual landfill unit either to a container located within the lined footprint of the respective landfill or directly to the leachate distribution system (sprinklers or drip hoses) for the respective landfill. No leachate leaves the landfill from which it was pumped and the leachate, at all times, remains over the lined area that collected the leachate. If not applied directly, the leachate is collected in a portable container that serves as a reservoir for times dust control is required. The leachate is piped to drip systems and sprinkler systems for dust control as required. The drip and sprinkler systems are activated during periods before and during dust generation weather. Leachate is not sprinkled on roadways to prevent potential tracking from the landfill. Sprinkler systems are configured and operated so that no leachate is allowed to drift out of the footprint of the respective landfill. Both sprinkler and drip systems are operated to prevent landfill sideslope erosion. Leachate application rates are controlled to prevent puddles, saturated soil conditions, excessive percolation, and runoff.

The wastewater treatment unit operator oversees the application of leachate to the landfill surface. The operator monitors and adjusts the system for appropriate leachate application rates, appropriate spray sizing for wind drift conditions, piping and equipment leaks and ground conditions.

Inspections of the landfill sprinkler and drip systems are conducted regularly. The inspector visually checks the leachate application area for evidence of spray leaving the footprint of the landfill, sideslope application, runoff and puddling.

DEQ Issued 3-5 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

Other dust control measures include:

Application of clean water from a water truck onto the exposed surface within the landfill; and

Spraying of clean water from a fire truck hose onto dry bulk wastes during unloading operations.

The water truck spray rate is equivalent to 0.012 inches of rain per year per application. Since the average daily evaporation rate is 0.10 inches per day, it is apparent that clean water applied in this manner will evaporate before it can percolate into the subsoils. Therefore, no groundwater contamination is possible with this method of dust control.

The procedure of spraying water via a water hose is only used when unloading dry bulk wastes such as baghouse dust. Assuming the waste has a moisture content of 5 percent, the amount of water sprayed is not sufficient to even achieve the normal moisture content (10 percent) of the soil used as clean cover in the landfills. Therefore, the additional water poses no threat to groundwater.

Dust emissions from earthmoving activities and truck haul roads and ramps are minimized on dry, windy days by periodic watering of areas being traveled and maintenance of a prepared road bed of aggregate material. Dust emissions from the active areas of the landfills are reduced with the compaction of surface materials by heavy equipment traffic.

The off-loading of container wastes in the landfills presents no dust emission problem. Most bulk solid wastes, which are end-dumped from trucks, are typically not dust-generating wastes because of their moisture content, large particles, and/or other physical properties. Stabilized wastes are non-dust generating. However, the unloading of fine particle bulk solids, such as fly ash or baghouse dust, is a potential dust emission problem. The current practice is to unload these wastes in an area of the landfill protected from wind and as close to the final disposal area as possible.

When the final cover is placed on each landfill, vegetation is established to control wind erosion of final cover soils.

3.9 Disposal of Dioxin-Containing Wastes (i.e., F020, F021, F022, F023, F026, F027, and F028

This management plan contains procedures for disposal of dioxin-containing wastes, which satisfy the special requirements for managing these wastes identified in 40 CFR § 264.317. The following items are addressed in this management plan:

• Exposure control practices;

• Volumes, concentrations of dioxin-containing wastes, and potential to migrate; and

DEQ Issued 3-6 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

• Disposal procedures for land disposal.

3.9.1 Exposure Control Practices

Existing management standards under 40 CFR § 264 Subpart N are adequate to prevent the dispersion of dioxin-contaminated wastes by wind dispersal. However, as an added precaution these wastes are disposed in sealed impermeable enclosures to eliminate any potential for dispersal of waste.

In instances where waste is transferred and/or stabilized into these enclosures for disposal, personnel are provided adequate personnel protective equipment as is detailed in the facility’s exposure monitoring and prevention procedures.

3.9.2 Waste Characteristics

The volumes of dioxin-containing wastes to be managed for landfill varies depending upon the process generating the waste. For example, dioxin-containing waste may be generated at large cleanup sites and transported in lined bulk containers and then landfilled in sealed bulk enclosures. In addition, these wastes may be generated and transported in small containers, such as well investigation samples to be stabilized and landfilled in one or more impermeable enclosures. The estimated volumes to be received for landfill are identified during the profile approval process for each waste stream.

The concentration of dioxin or furans in the wastes designated as F020, F021, F022, F023, F026, F027, intended to be managed for disposal at the Arlington Facility, are below the regulated levels identified in 40 CFR § 268.40 for wastewaters or non-wastewaters except for debris and wastes intended to be managed for disposal as corrective action management unit (CAMU)- eligible wastes.

Debris contaminated waste can be treated in accordance with the alternative treatment standard in 40 CFR § 268.45 as discussed in Standalone Document No. 11, Debris Treatment Plan.

All of these wastes accepted at the Arlington Facility for landfilling are disposed of in impermeable enclosures that are capped and sealed to reduce the possibility of migration of these wastes to groundwater, surface water, or air so as to protect human health and the environment.

3.9.3 Disposal Procedures

As identified above, all dioxin-containing wastes that are disposed of in a landfill will be confined within an impermeable enclosure that is later capped and sealed. These enclosures may be drums, prefabricated HDPE macroencapsulation boxes, super sacks (non-rigid containers consisting of an inner layer of impermeable material (such as polyethelene) and an outer layer of woven fabric capable of withstanding waste loading, transport, and disposal without tearing), or may be constructed of flexible membrane liner (FML) within the landfill. FMLs may be polyethylene (HDPE, LLDPE) or other materials as appropriate. Macroencapsulation enclosures constructed within the landfill will have FML above and below the waste to be encapsulated with

DEQ Issued 3-7 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan the overlying FML seamed to the underlying FML at the edges. All macroencapsulation FML panels will be seamed using either fusion or extrusion methods.

CQA of macroencapsulation enclosures within the landfill will consist of non-destructive testing of the seams in accordance with the Construction Quality Assurance Plan. Other requirements of the Construction Quality Assurance Plan may be implemented at the CQA Engineer’s discretion. ‡ Rev. 5

Liquids accepted for disposal in a landfill are solidified prior to being landfilled. All containers, in which these wastes have been removed and where the waste has contacted the container, are triple rinsed to remove any hazardous residue. This rinsate is also stabilized and landfilled in similar enclosures discussed above

DEQ Issued 3-8 Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

Figure 3-1

DEQ Issued Revision 8: December 2015 Chemical Waste Management of the Northwest, Inc. Standalone Document No. 14  Landfill Design and Operations Plan

APPENDIX A

Calculations For Design of L-14

Page 1 of 4 Client: CWMNW Project: L-14 Expansion Revision 1n Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

INTERMEDIATE SLOPE STABILITY ANALYSIS

Objective

Determine the intermediate slope stability of the landfill of the proposed expansion. Both static and pseudo seismic loading will be evaluated.

Requirements

The applicable federal and state regulations do not contain minimum prescriptive requirements for factors of safety against landfill instability. For static conditions, a factor of safety of 1.5 is a generally accepted minimum value for long-term landfill slope stability and is the recommended minimum value in the ODEQ Solid Waste Landfill Guidance Document. For short term conditions, such as those encountered during filling of the landfill, a static factor of safety of 1.3 is a generally accepted value.

For seismic conditions, factors of safety above 1.0 are typically considered adequate. If the estimated factor of safety is less than 1.0, then a deformation analyses is performed. If deformations are within allowable limits, then the design is considered acceptable.

Required factors of safety need to be considered in conjunction with the overall level of conservatism of the analysis. For example, if post-peak interface shear strength values are used, required factors of safety are typically lower than if peak values are used. A discussion of peak and post-peak assumptions is included later in this analysis.

Method:

The limit equilibrium approach is used for the calculations. The slope stability software Galena (Version. 5.02) is utilized. The analyses are performed to determine the lowest factors of safety of the weakest points in the liner system.

For the static analyses, post-peak strength values for the critical interface are used. Without an earthquake load there is no slope loading condition that is expected to exceed the peak strength of the materials and cause the lower post-peak strengths to be mobilized, so this analysis is conservative.

For the seismic analyses, peak strength values for the critical interface are used. The 0.1819g seismic force applied to the landfill under the earthquake condition corresponds to the peak bedrock acceleration value expected from the design seismic event. That is, the 0.1819g force is the maximum destabilizing force that the landfill will experience. If a factor of safety against sliding can be maintained greater than 1.0 in this scenario, then no displacement should occur to cause the post-peak interface strength to be mobilized. Therefore, using the peak strength for the seismic analysis is reasonable.

Page 2 of 4 Client: CWMNW Project: L-14 Expansion Revision 1n Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

INTERMEDIATE SLOPE STABILITY ANALYSIS

References:

1. Bray, Jonathan D. and Ellen Rathje, Earthquake-Induced Displacements of Solid Waste Landfills, Jounranl of Geotechnical and Geoenvironmental Engineering, March 1998, Vol 124, pp. 242-253.

2. Kavazanjian Jr., E., Matasovi, N., Bonaparte, R., and Schmertmann, G. R. (1995) “Evaluation of MSW Properties for Seismic Analysis”, Geoenvironment 2000 Proceedings, ASCE, pp. 1126-1141.

3. Solid Waste Guidance Document, Oregon Department of Environmental Quality, www.deq.state.or.us/lq/sw/disposal/landfillguidance.htm

4. USGS National Seismic Hazard Mapping Project Interactive Deaggregation. 200910 Update. http://earthquake.usgs.gov/hazards/apps/.

Given

1. The waste strength is taken from data presented in Kavazanjian, 1995.

2. Peak ground acceleration = 0.1819g. The acceleration has a 2 percent change of being exceeded in 50 years or a 10% chance of being exceeded in 250 years. Taken from the 200910 update of the Interactive Deaggregation of the USGS National Seismic Hazard Mapping Project.

3. The interface strength of the liner system is defined as a normal stress vs. shear stress table based on the interface testing performed on the liner system. Interface strength values for Cells 1 through 3 are based on testing performed for Cell 3, which is considered representative. Interface strength values for Cells 4 and 5 are based on testing performed in 2013 which accounts for the use of a GCL in the secondary composite liner system. The interface test reports are attached to the waste mass stability calculations..

4. When a minimum material strength is specified in these calculations it is implied to mean that the normal stress / shear strength data of the material plots above a line defined by the equation

τ = σn tan(Φ°), where τ is the shear strength of the liner interface, and σn is the normal stress on the liner system. The equation is valid for the normal stress range of 0 to the maximum stress experienced by the material in the referenced model section.

Assumptions

1. The critical section is assumed to be a north-south section through Cells 4 and 5. It represents the point at which Cells 1 through 4 are filled to their interim capacity and Cell 5 is excavated but has no waste in place. Other sections were evaluated, including the possibility of filling Cell 5 before

Page 3 of 4 Client: CWMNW Project: L-14 Expansion Revision 1n Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

INTERMEDIATE SLOPE STABILITY ANALYSIS

Cell 4, however, the fill height and cell geometry of the noted section (Cells 1-4 filled, Cell 5 excavated) still appears to be the most critical.

2. The weakest and therefore critical material in the landfill stability is the geosynthetic liner interface. The subsoil and waste are stronger than the interfaces of the geosynthetics with either material.

3. Because the interim grade configuration used in these analyses represents a relatively short-term condition, peak interface strength values are used in the seismic analysis. It is assumed that under these short term conditions, significant displacement along the failure plane has not occurred. For the static analysis, large displacement interface strength values are used. The factor of safety calculated in this scenario could represent the intermediate slope under static conditions after a seismic event has caused enough displacement along the failure plane to mobilize the large displacement strength.

4. The modeled section is assumed to be the critical section since it passes through the thickest parts of the landfill. In addition, this section has the longest and steepest slope of the intermediate fill conditions.

5. The subsoil strength is estimated.

6. The leachate level was assumed to be 1 foot above the top of the liner and considered a phreatic surface.

7. No piezometric groundwater level was set to act on the liner system for any of the simulations.

Calculations

The calculations were performed with the slope stability software program Galena and are attached.

Page 4 of 4 Client: CWMNW Project: L-14 Expansion Revision 1n Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

INTERMEDIATE SLOPE STABILITY ANALYSIS

Results:

Calculated Required Model Section Analysis Failure Accep- Factor of Factor of Run Description Condition Surface table? Safety Safety 001 North-South Static 1.30 1.3 Liner Yes Through System Cell 4

002 North-South Seismic 1.29 1.0 Liner Yes through System Cell 4

The intermediate grades of the proposed expansion meet the required factors of safety under static and seismic design scenarios.

Potential failure surfaces passing through waste show factors of safety substantially above the requirements.

bin)

ε

350

9.0

8.5

300 8.0 7.5

=1.0

ε

7.0

250 MAGNITUDE (Mw) MAGNITUDE 6.5

W, 45.600 N.

o (km) Rcd Distance, Closest

6.0

200

5.5

5.0 150

350 ) = 6.9 km, 5.20, -0.19 (from peak R,M bin) ) 28.3 km, 6.08, 0.39 0 *) = 14.9 km, 5.40, 1 to 2 sigma (from peak R,M,

0 ε ε

ε 100

300

Modal (R,M, PSH Deaggregation on NEHRP BC rock CWMNW_-_L14 120.200 Peak Horiz. Ground Accel.>=0.1819 g Ann. Exceedance Rate .405E-03. Mean Return Time 2475 years Mean (R,M, Modal (R,M, Binning: DeltaR 10. km, deltaM=0.2, Delta 50

250 0 200

9.0 200910 UPDATE

8.5 < 1

150 0 < 0.5 < 2 < 3 ε 0 0 0

8.0 ε ε ε Closest Distance, Rcd (km)

7.5 0 < 0.5 < 1 < 2 < MAGNITUDE (Mw)

7.0 100 >median

6.5 Distance (R), magnitude (M), epsilon (E0,E) deaggregation for a site on rock with average vs= 760. m/s top 30 m. USGS CGHT PSHA2008 UPDATE Bins lt 0.05% contrib. omitted < 0 0 < -1 <-0.5 ε 0 0 ε 6.0 ε 50 < -2 0 -1 < -0.5 < -2 < 5.5 ε

Prob. SA, PGA

10 8 6 4 2 5.0 % Contribution to Hazard to Contribution % 0 2010 Sep 28 17:13:17 GMT GALENA Version 5.02

Waste

Structural Fill

Liner Peak

Liner Post Peak

1250 Sub Grade CWMNW - L14 Base Liner Revision 1200

North South 1150

1100

:1 1050 3 Waste Analysis: 1 1000 Multiple Stability Analysis Liner System, 1.5% Slope Method: Sarma 950 Surface: Non-Circular

900 Results Critical (minimum) Factor of Safety: 1.30 Critical Acceleration (Kc): 0.069 850

800 Edited:9 Sep 2013 Processed: 9 Sep 2013

750 100 200 300 400 500 600 700 800

Project:CWMNW - L-14 Base Liner Revision - North South Section 1 Intermediate 3:1 Slope File: Run 001 NS Inter Stat.gmf Licensed to: Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\Documents\EIL PROJECTS\Chem Waste\L-14 Expansion\2013\Slope Stability Interme...\Run 001 NS Inter Stat.gmf Processed: 09 Sep 2013 14:52:19 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Intermediate 3:1 Slope

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 22000.00 8000.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 22000.00 2800.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (3 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 100.00 1100.00 800.00 1100.00 Profile: 2 (3 points) Material beneath: 5 - Sub Grade 100.00 940.50 200.00 939.00 800.00 930.00 Profile: 3 (3 points) Material beneath: 4 - Liner Post Peak 100.00 945.50 200.00 944.00 800.00 935.00

Slope Surface (4 points) ------100.00 945.50 200.00 944.00 632.00 1084.00 800.00 1084.00

Phreatic Surface (2 points) ------200.00 944.00 800.00 936.00

Failure Surface ------Initial non-circular surface for critical search (4 points) 200.00 944.00 210.00 942.80 450.00 939.10 583.34 1068.23

Variable Restraints ------Horizontal range around X-Left: 5.00 Trial positions within range: 5 Horizontal range around X-Right: 200.00 Trial positions within range: 40 Vertical range around Mid-Point: 2.00 Trial positions within range: 2

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Intermediate 3:1 Slope

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Solution did not converge for initial failure surface approximation Last calculated Factor of Safety was *****

There were: 340 successful analyses from a total of 401 trial surfaces 61 analyses that failed to produce a result

Critical (minimum) Factor of Safety: 1.30 —————————————————————————————————————————— Critical Acceleration (Kc): 0.069

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 201.25 944.41 611.54 1077.37 -1.00 1.301 0.069 2 201.25 944.41 621.80 1080.69 -1.00 1.301 0.069 3 197.50 944.04 616.67 1079.03 -1.00 1.301 0.069 4 201.25 944.41 606.42 1075.71 -1.00 1.302 0.069 5 198.75 944.02 611.54 1077.37 -1.00 1.302 0.070 6 197.50 944.04 611.54 1077.37 -1.00 1.302 0.070 7 201.25 944.41 616.67 1079.03 -1.00 1.302 0.069 8 201.25 944.41 626.93 1082.36 -1.00 1.303 0.070 9 198.75 944.02 642.31 1084.00 -1.00 1.303 0.069 10 198.75 944.02 621.80 1080.69 -1.00 1.303 0.070 11 197.50 944.04 621.80 1080.69 -1.00 1.303 0.070 12 201.25 944.41 601.29 1074.05 -1.00 1.303 0.070 13 198.75 944.02 606.42 1075.71 -1.00 1.303 0.070 14 197.50 944.04 606.42 1075.71 -1.00 1.303 0.070 15 198.75 944.02 616.67 1079.03 -1.00 1.303 0.070 16 201.25 944.41 632.06 1084.00 -1.00 1.304 0.070 17 198.75 944.02 601.29 1074.05 -1.00 1.304 0.070 18 198.75 944.02 626.93 1082.36 -1.00 1.304 0.070 19 197.50 944.04 601.29 1074.05 -1.00 1.304 0.070 20 197.50 944.04 626.93 1082.36 -1.00 1.304 0.070 21 198.75 944.02 637.18 1084.00 -1.00 1.304 0.070 22 198.75 944.02 596.16 1072.38 -1.00 1.305 0.070 23 201.25 944.41 637.18 1084.00 -1.00 1.305 0.070 24 197.50 944.04 596.16 1072.38 -1.00 1.305 0.070 25 197.50 944.04 637.18 1084.00 -1.00 1.305 0.070 26 198.75 944.02 632.06 1084.00 -1.00 1.305 0.070 27 197.50 944.04 632.06 1084.00 -1.00 1.305 0.070 28 198.75 944.02 647.44 1084.00 -1.00 1.306 0.070 29 198.75 944.02 591.03 1070.72 -1.00 1.306 0.070 30 198.75 944.02 585.90 1069.06 -1.00 1.307 0.071 31 198.75 944.02 652.57 1084.00 -1.00 1.307 0.070 32 197.50 944.04 642.31 1084.00 -1.00 1.307 0.071 33 198.75 944.02 580.77 1067.40 -1.00 1.308 0.071 34 201.25 944.41 596.16 1072.38 -1.00 1.308 0.071 35 201.25 944.41 591.03 1070.72 -1.00 1.309 0.071 36 197.50 944.04 591.03 1070.72 -1.00 1.310 0.072 37 201.25 944.41 585.90 1069.06 -1.00 1.310 0.072 38 197.50 944.04 647.44 1084.00 -1.00 1.311 0.071 39 198.75 944.02 657.70 1084.00 -1.00 1.311 0.071 40 197.50 944.04 585.90 1069.06 -1.00 1.311 0.072 41 197.50 944.04 580.77 1067.40 -1.00 1.312 0.072 42 197.50 944.04 652.57 1084.00 -1.00 1.312 0.072 43 198.75 944.02 667.95 1084.00 -1.00 1.313 0.071 44 198.75 944.02 575.65 1065.74 -1.00 1.313 0.072 45 197.50 944.04 575.65 1065.74 -1.00 1.313 0.072 46 198.75 944.02 570.52 1064.08 -1.00 1.314 0.073 47 198.75 944.02 565.39 1062.41 -1.00 1.315 0.073 48 197.50 944.04 657.70 1084.00 -1.00 1.316 0.072 49 198.75 944.02 560.26 1060.75 -1.00 1.316 0.073 50 198.75 944.02 662.83 1084.00 -1.00 1.316 0.072 51 201.25 944.41 642.31 1084.00 -1.00 1.317 0.072 52 198.75 944.02 555.13 1059.09 -1.00 1.317 0.073 53 202.50 944.81 611.54 1077.37 -1.00 1.318 0.073 54 201.25 944.41 580.77 1067.40 -1.00 1.318 0.074 55 198.75 944.02 673.08 1084.00 -1.00 1.318 0.072 56 198.75 944.02 550.00 1057.43 -1.00 1.319 0.074 57 202.50 944.81 606.42 1075.71 -1.00 1.319 0.073 58 201.25 944.41 575.65 1065.74 -1.00 1.320 0.074 59 202.50 944.81 616.67 1079.03 -1.00 1.320 0.073 60 202.50 944.81 626.93 1082.36 -1.00 1.320 0.073 61 197.50 944.04 667.95 1084.00 -1.00 1.320 0.072 62 201.25 944.41 555.13 1059.09 -1.00 1.320 0.075 63 202.50 944.81 601.29 1074.05 -1.00 1.320 0.073 64 201.25 944.41 570.52 1064.08 -1.00 1.321 0.074 65 201.25 944.41 647.44 1084.00 -1.00 1.321 0.073 66 202.50 944.81 632.06 1084.00 -1.00 1.321 0.073 67 202.50 944.81 621.80 1080.69 -1.00 1.321 0.073 68 197.50 944.04 570.52 1064.08 -1.00 1.321 0.074 69 197.50 944.04 662.83 1084.00 -1.00 1.321 0.073 70 201.25 944.41 550.00 1057.43 -1.00 1.322 0.075 71 202.50 944.81 596.16 1072.38 -1.00 1.322 0.073 72 201.25 944.41 565.39 1062.41 -1.00 1.322 0.074 73 197.50 944.04 565.39 1062.41 -1.00 1.322 0.075 74 202.50 944.81 637.18 1084.00 -1.00 1.323 0.073 75 202.50 944.81 591.03 1070.72 -1.00 1.323 0.074 76 201.25 944.41 544.88 1055.77 -1.00 1.323 0.076 77 201.25 944.41 652.57 1084.00 -1.00 1.323 0.073 78 202.50 944.81 642.31 1084.00 -1.00 1.323 0.073 79 201.25 944.41 560.26 1060.75 -1.00 1.323 0.075 80 197.50 944.04 560.26 1060.75 -1.00 1.323 0.075 81 198.75 944.02 539.75 1054.10 -1.00 1.324 0.076 82 202.50 944.81 585.90 1069.06 -1.00 1.324 0.074 83 197.50 944.04 555.13 1059.09 -1.00 1.324 0.075 84 198.75 944.02 534.62 1052.44 -1.00 1.325 0.076 85 197.50 944.04 529.49 1050.78 -1.00 1.325 0.076 86 202.50 944.81 580.77 1067.40 -1.00 1.325 0.075 87 197.50 944.04 550.00 1057.43 -1.00 1.326 0.075 88 197.50 944.04 673.08 1084.00 -1.00 1.326 0.073 89 202.50 944.81 575.65 1065.74 -1.00 1.326 0.076 90 202.50 944.81 647.44 1084.00 -1.00 1.326 0.074 91 198.75 944.02 544.88 1055.77 -1.00 1.327 0.076 92 197.50 944.04 524.36 1049.12 -1.00 1.327 0.077 93 197.50 944.04 544.88 1055.77 -1.00 1.327 0.076 94 201.25 944.41 657.70 1084.00 -1.00 1.327 0.074 95 202.50 944.81 570.52 1064.08 -1.00 1.328 0.076 96 197.50 944.04 539.75 1054.10 -1.00 1.328 0.077 97 197.50 944.04 519.24 1047.46 -1.00 1.328 0.077 98 201.25 944.41 539.75 1054.10 -1.00 1.328 0.077 99 202.50 944.81 565.39 1062.41 -1.00 1.329 0.076 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (4 points) ------201.25 944.41 211.95 942.29 468.83 938.25 611.54 1077.37

Non-Vertical Slice Geometry (3 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 201.25 944.41 201.25 944.41 27.55 -11.2 10.70 10.91 0.0 0.00 2 211.12 947.60 211.95 942.29 11278.57 -0.9 256.88 256.91 -8.9 5.38 3 439.34 1021.56 468.83 938.25 7996.27 44.3 142.71 199.30 -19.5 88.38 RHS 611.54 1077.37 611.54 1077.37 ------0.0 0.00 X-S Area: 19302.39 Path Length: 467.12

Non-Vertical Slice Properties (3 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 -1.50 23.1 0.00 0.0 2756.21 0.00 0.00 405.48 0.00 363.29 0.00 2 137.42 8.5 -5.63 29.5 1221875.25 0.00 0.00 29799.47 78.46 5502.98 409.85 3 2.99 32.5 2.81 32.5 879561.38 0.00 0.00 165.76 1356.54 3128.88 3118.72 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 2104193.00

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— GALENA Version 5.02

Structural Fill

Liner Peak

Liner Post Peak

0.182 Sub Grade 1250

CWMNW - L14 Base Liner Revision 1200

North South 1150

1100

:1 1050 3 Waste Analysis: 1 1000 Multiple Stability Analysis Liner System, 1.5% Slope Method: Sarma 950 Surface: Non-Circular

900 Results Critical (minimum) Factor of Safety: 1.29 Critical Acceleration (Kc): 0.140 850

800 Edited:9 Sep 2013 Processed: 9 Sep 2013

750 100 200 300 400 500 600 700 800

Project:CWMNW - L-14 Base Liner Revision - North South Section 2 Intermediate 3:1 Slope File: Run 002 NS Inter EQ.gmf Licensed to: Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\Documents\EIL PROJECTS\Chem Waste\L-14 Expansion\2013\Slope Stability Intermedi...\Run 002 NS Inter EQ.gmf Processed: 09 Sep 2013 16:45:09 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Intermediate 3:1 Slope

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 22000.00 8000.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 22000.00 2800.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (3 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 100.00 1100.00 800.00 1100.00 Profile: 2 (3 points) Material beneath: 5 - Sub Grade 100.00 940.50 200.00 939.00 800.00 930.00 Profile: 3 (3 points) Material beneath: 3 - Liner Peak 100.00 945.50 200.00 944.00 800.00 935.00

Slope Surface (4 points) ------100.00 945.50 200.00 944.00 632.00 1084.00 800.00 1084.00

Phreatic Surface (2 points) ------200.00 944.00 800.00 936.00

Failure Surface ------Initial non-circular surface for critical search (3 points) 200.00 944.00 450.00 936.10 583.34 1068.23

Earthquake Force ------Pseudo-static earthquake (seismic) coefficient: 0.182

Variable Restraints ------Horizontal range around X-Left: 5.00 Trial positions within range: 5 Horizontal range around X-Right: 200.00 Trial positions within range: 40 Vertical range around Mid-Point: 2.00 Trial positions within range: 2

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Intermediate 3:1 Slope

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Factor of Safety for initial failure surface approximation: 2.79

There were: 401 successful analyses from a total of 401 trial surfaces

Critical (minimum) Factor of Safety: 1.29 —————————————————————————————————————————— Critical Acceleration (Kc): 0.140

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 197.50 944.04 657.70 1084.00 1.00 1.291 0.140 2 198.75 944.02 657.70 1084.00 1.00 1.292 0.140 3 198.75 944.02 652.57 1084.00 1.00 1.293 0.141 4 197.50 944.04 678.21 1084.00 1.00 1.293 0.138 5 197.50 944.04 642.31 1084.00 1.00 1.294 0.143 6 198.75 944.02 678.21 1084.00 1.00 1.294 0.138 7 197.50 944.04 683.34 1084.00 1.00 1.294 0.137 8 197.50 944.04 667.95 1084.00 1.00 1.295 0.140 9 197.50 944.04 647.44 1084.00 1.00 1.295 0.142 10 198.75 944.02 642.31 1084.00 1.00 1.295 0.144 11 197.50 944.04 673.08 1084.00 1.00 1.295 0.139 12 198.75 944.02 683.34 1084.00 1.00 1.295 0.138 13 198.75 944.02 667.95 1084.00 1.00 1.295 0.140 14 198.75 944.02 647.44 1084.00 1.00 1.295 0.142 15 197.50 944.04 637.18 1084.00 1.00 1.295 0.144 16 198.75 944.02 673.08 1084.00 1.00 1.296 0.140 17 197.50 944.04 662.83 1084.00 1.00 1.296 0.141 18 197.50 944.04 616.67 1079.03 1.00 1.296 0.146 19 197.50 944.04 652.57 1084.00 1.00 1.296 0.143 20 198.75 944.02 637.18 1084.00 1.00 1.296 0.145 21 198.75 944.02 662.83 1084.00 1.00 1.297 0.141 22 197.50 944.04 611.54 1077.37 1.00 1.297 0.146 23 197.50 944.04 580.77 1067.40 1.00 1.297 0.146 24 197.50 944.04 575.65 1065.74 -1.00 1.297 0.148 25 197.50 944.04 621.80 1080.69 1.00 1.297 0.146 26 197.50 944.04 606.42 1075.71 1.00 1.297 0.147 27 197.50 944.04 575.65 1065.74 1.00 1.298 0.147 28 197.50 944.04 570.52 1064.08 -1.00 1.298 0.148 29 198.75 944.02 611.54 1077.37 1.00 1.298 0.147 30 198.75 944.02 621.80 1080.69 1.00 1.298 0.146 31 198.75 944.02 606.42 1075.71 1.00 1.298 0.147 32 198.75 944.02 580.77 1067.40 1.00 1.298 0.147 33 197.50 944.04 601.29 1074.05 1.00 1.298 0.147 34 197.50 944.04 626.93 1082.36 1.00 1.299 0.146 35 197.50 944.04 570.52 1064.08 1.00 1.299 0.147 36 197.50 944.04 565.39 1062.41 -1.00 1.299 0.149 37 197.50 944.04 596.16 1072.38 1.00 1.299 0.147 38 198.75 944.02 575.65 1065.74 1.00 1.299 0.147 39 198.75 944.02 570.52 1064.08 -1.00 1.299 0.149 40 198.75 944.02 601.29 1074.05 1.00 1.299 0.147 41 198.75 944.02 616.67 1079.03 1.00 1.299 0.147 42 197.50 944.04 565.39 1062.41 1.00 1.299 0.148 43 197.50 944.04 560.26 1060.75 -1.00 1.300 0.149 44 198.75 944.02 626.93 1082.36 1.00 1.300 0.147 45 198.75 944.02 570.52 1064.08 1.00 1.300 0.148 46 197.50 944.04 632.06 1084.00 1.00 1.300 0.147 47 198.75 944.02 565.39 1062.41 -1.00 1.300 0.149 48 197.50 944.04 591.03 1070.72 1.00 1.300 0.148 49 198.75 944.02 596.16 1072.38 1.00 1.300 0.148 50 197.50 944.04 560.26 1060.75 1.00 1.300 0.148 51 197.50 944.04 555.13 1059.09 -1.00 1.300 0.150 52 198.75 944.02 565.39 1062.41 1.00 1.301 0.148 53 198.75 944.02 632.06 1084.00 1.00 1.301 0.147 54 197.50 944.04 585.90 1069.06 1.00 1.301 0.148 55 198.75 944.02 560.26 1060.75 -1.00 1.301 0.150 56 197.50 944.04 555.13 1059.09 1.00 1.301 0.149 57 198.75 944.02 591.03 1070.72 1.00 1.301 0.148 58 198.75 944.02 560.26 1060.75 1.00 1.301 0.149 59 198.75 944.02 555.13 1059.09 -1.00 1.302 0.150 60 198.75 944.02 585.90 1069.06 1.00 1.302 0.149 61 198.75 944.02 555.13 1059.09 1.00 1.302 0.149 62 197.50 944.04 483.34 1035.82 -1.00 1.303 0.152 63 197.50 944.04 488.47 1037.48 -1.00 1.303 0.152 64 197.50 944.04 483.34 1035.82 1.00 1.303 0.150 65 197.50 944.04 678.21 1084.00 -1.00 1.303 0.145 66 197.50 944.04 529.49 1050.78 -1.00 1.303 0.151 67 197.50 944.04 488.47 1037.48 1.00 1.303 0.150 68 197.50 944.04 529.49 1050.78 1.00 1.304 0.150 69 197.50 944.04 524.36 1049.12 -1.00 1.304 0.152 70 198.75 944.02 678.21 1084.00 -1.00 1.304 0.145 71 197.50 944.04 580.77 1067.40 -1.00 1.304 0.151 72 197.50 944.04 683.34 1084.00 -1.00 1.304 0.144 73 197.50 944.04 519.24 1047.46 -1.00 1.304 0.152 74 198.75 944.02 483.34 1035.82 1.00 1.304 0.151 75 197.50 944.04 524.36 1049.12 1.00 1.304 0.151 76 198.75 944.02 483.34 1035.82 -1.00 1.304 0.153 77 198.75 944.02 488.47 1037.48 1.00 1.304 0.151 78 198.75 944.02 529.49 1050.78 -1.00 1.304 0.152 79 198.75 944.02 488.47 1037.48 -1.00 1.305 0.153 80 197.50 944.04 514.11 1045.79 -1.00 1.305 0.153 81 197.50 944.04 519.24 1047.46 1.00 1.305 0.151 82 198.75 944.02 683.34 1084.00 -1.00 1.305 0.145 83 197.50 944.04 550.00 1057.43 -1.00 1.305 0.152 84 198.75 944.02 529.49 1050.78 1.00 1.305 0.151 85 197.50 944.04 514.11 1045.79 1.00 1.305 0.151 86 198.75 944.02 580.77 1067.40 -1.00 1.305 0.152 87 198.75 944.02 524.36 1049.12 -1.00 1.305 0.153 88 197.50 944.04 508.98 1044.13 -1.00 1.305 0.153 89 197.50 944.04 544.88 1055.77 -1.00 1.305 0.153 90 197.50 944.04 503.85 1042.47 -1.00 1.305 0.153 91 197.50 944.04 550.00 1057.43 1.00 1.305 0.151 92 198.75 944.02 524.36 1049.12 1.00 1.306 0.151 93 197.50 944.04 498.72 1040.81 -1.00 1.306 0.153 94 198.75 944.02 519.24 1047.46 -1.00 1.306 0.153 95 197.50 944.04 508.98 1044.13 1.00 1.306 0.152 96 197.50 944.04 503.85 1042.47 1.00 1.306 0.152 97 198.75 944.02 575.65 1065.74 -1.00 1.306 0.152 98 197.50 944.04 498.72 1040.81 1.00 1.306 0.152 99 198.75 944.02 519.24 1047.46 1.00 1.306 0.152 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (3 points) ------197.50 944.04 497.62 936.13 657.70 1084.00

Non-Vertical Slice Geometry (4 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 197.50 944.04 197.50 944.04 0.04 -1.5 2.50 2.50 0.0 0.00 2 200.00 944.00 200.00 943.97 13880.04 -1.5 297.62 297.72 -7.5 0.03 3 466.02 1030.21 497.62 936.13 10345.49 42.7 142.23 193.62 -18.6 99.24 4 632.00 1084.00 639.85 1067.52 211.80 42.7 17.85 24.29 -25.5 18.26 RHS 657.70 1084.00 657.70 1084.00 ------0.0 0.00 X-S Area: 24437.36 Path Length: 518.15

Non-Vertical Slice Properties (4 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 0.00 32.2 0.00 0.0 2.31 0.00 -0.42 0.00 0.00 1.25 0.00 2 293.36 21.4 0.00 32.2 1503909.88 0.00 -273711.59 36487.02 0.03 6409.43 43.63 3 10.07 32.7 14.50 32.5 1137638.00 0.00 -207050.11 678.72 1969.11 3486.16 5398.51 4 0.00 33.0 0.00 33.0 23298.24 0.00 -4240.28 0.00 0.00 498.99 635.50 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 2664848.25

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Page 1 of 4 Client: CWMNW Project: L-14 Expansion Revision 2 Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

WASTE MASS STABILITY ANALYSIS

Objective

Determine the waste mass stability of the landfill at final grade of the proposed expansion. Both static and pseudo-seismic loading will be evaluated.

Requirements

The applicable federal and state regulations do not contain minimum prescriptive requirements for factors of safety against landfill instability. For static conditions, a factor of safety of 1.5 is a generally accepted minimum value for long-term landfill slope stability and is the recommended minimum value in the ODEQ Solid Waste Landfill Guidance Document. For short term conditions, such as those encountered during filling of the landfill, a static factor of safety of 1.3 is a generally accepted value.

For seismic conditions, factors of safety above 1.0 are typically considered adequate. If the estimated factor of safety is less than 1.0, then a deformation analyses is performed. If deformations are within allowable limits, then the design is considered acceptable.

Required factors of safety need to be considered in conjunction with the overall level of conservatism of the analysis. For example, if post-peak interface shear strength values are used, required factors of safety are typically lower than if peak values are used. A discussion of peak and post-peak assumptions is included later in this analysis.

Method:

The limit equilibrium approach will be used for the calculations. The slope stability software Galena (Version. 5.02) will be utilized. The analyses are performed to determine the lowest factors of safety of the weakest points in the liner system.

For the static analyses, post-peak strength values for the critical interface are used. Without an earthquake load there is no slope loading condition that is expected to exceed the peak strength of the materials and cause the lower post-peak strengths to be mobilized, so this analysis is conservative.

For the seismic analyses, peak strength values for the critical interface are used. The 0.1819g seismic force applied to the landfill under the earthquake condition corresponds to the peak bedrock acceleration value expected from the design seismic event. That is, the 0.1819g force is the maximum destabilizing force that the landfill will experience. If a factor of safety against sliding can be maintained greater than 1.0 in this scenario, then no displacement should occur to cause the post-peak interface strength to be mobilized. Therefore, using the peak strength for the seismic analysis is reasonable.

Page 2 of 4 Client: CWMNW Project: L-14 Expansion Revision 2 Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

WASTE MASS STABILITY ANALYSIS

References:

1. Bray, Jonathan D. and Ellen Rathje, Earthquake-Induced Displacements of Solid Waste Landfills, Jounranl of Geotechnical and Geoenvironmental Engineering, March 1998, Vol 124, pp. 242-253.

2. Kavazanjian Jr., E., Matasovi, N., Bonaparte, R., and Schmertmann, G. R. (1995) “Evaluation of MSW Properties for Seismic Analysis”, Geoenvironment 2000 Proceedings, ASCE, pp. 1126-1141.

3. Solid Waste Guidance Document, Oregon Department of Environmental Quality, www.deq.state.or.us/lq/sw/disposal/landfillguidance.htm

4. USGS National Seismic Hazard Mapping Project Interactive Deaggregation. 200910 update. http://earthquake.usgs.gov/hazards/apps/.

Given

1. Waste strength is taken from data presented in Kavazanjian, 1995.

2. Peak ground acceleration = 0.1819g. The acceleration has a 2 percent change of being exceeded in 50 years or a 10% chance of being exceeded in 250 years. Taken from the 2009-10 update of the Interactive Deaggregation of the USGS National Seismic Hazard Mapping Project.

3. The interface strength of the liner system is defined as a normal stress vs. shear stress table based on the interface testing performed on the liner system. Interface strength values for Cells 1 through 3 are based on testing performed for Cell 3, which is considered representative. Interface strength values for Cells 4 and 5 are based on testing performed in 2013 which accounts for the use of a GCL in the secondary composite liner system. The interface test reports are attached.

4. When a minimum material strength is specified in these calculations, it is implied to mean that the normal stress / shear strength data of the material plots above a line defined by the equation

τ = σn tan(Φ°), where τ is the shear strength of the liner interface, and σn is the normal stress on the liner system. The equation is valid for the normal stress range of 0 to the maximum stress experienced by the material in the referenced model section.

Assumptions

1. The critical section is a north-south line passing through Cells 3 and 5 (shown on the attached figures). This section cuts through the thickest parts of the landfill, and it has the longest and steepest slopes with the smallest buttresses. Analyses were performed for the north facing slope

Page 3 of 4 Client: CWMNW Project: L-14 Expansion Revision 2 Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

WASTE MASS STABILITY ANALYSIS

of this section. The south facing slope is nearly identically geometrically and the interface shear strength of liner system of Cells 1-3 is slightly greater. Therefore, analysis of the north facing slope is the most conservative.

2. The critical section that is analyzed assumes that the remainder of existing surface water detention basin B-2 is not filled to the north of the berm that will form the northern boundary of L-14. Current plans are to place fill in this area to facilitate surface water drainage. However, assuming that the area is not filled is more conservative for these calculations.

3. The weakest and therefore critical material in the landfill stability is the geosynthetic liner interface. The subsoil and waste are stronger than the interfaces of the geosynthetics with either material. The leachate level was assumed to be 1 foot above the top of the liner and considered a phreatic surface.

4. Because the final grade configuration used in these analyses represents a long-term condition, large displacement interface strength values are used. It is assumed that enough displacement has occurred along the failure plane to mobilize the large displacement strength.

5. No piezometric groundwater level was set to act on the liner system for any of the simulations.

6. The shear strength of the structural berm on the north side of L-14 was assumed to have a strength equal to or greater than 32.5 degrees or equivalent. Calculations were performed that evaluate the stability of the berm with the landfill at final grade. These confirm that the overall critical surfaces do not run through the berm.

Calculations

The calculations were performed with the slope stability software program Galena and are attached.

Page 4 of 4 Client: CWMNW Project: L-14 Expansion Revision 2 Calculated By: DW Date: 09/11/13 Checked By: ED Date: 09/11/13

WASTE MASS STABILITY ANALYSIS

Results:

Model Section Analysis Calculated Minimum Failure Run Description Condition Factor of Required Surface Safety Factor of Safety 001 North Berm Static 2.55 1.5 Berm 002 Liner System Static 1.95 1.5 Base Liner & Waste Mass 003 North Berm Seismic 1.66 1.0 Berm 004 Liner System Seismic 1.11 1.0 Base Liner & Waste Mass

The stability of the waste mass and liner system under the final grade configuration of the landfill meets the required factors of safety under static and seismic design scenarios.

350

9.0

8.5

300 8.0

7.5

7.0

250 MAGNITUDE (Mw) MAGNITUDE 6.5

W, 45.600 N.

o (km) Rcd Distance, Closest

6.0

200

5.5

5.0 150

350 ) = 6.9 km, 5.20, -0.19 (from peak R,M bin)

) 28.3 km, 6.08, 0.39 0

0 100

300

Modal (R,M, ε Modal (R,M, ε *) = 14.9 km, 5.40, 1 to 2 sigma (from peak R,M, bin) Binning: DeltaR 10. km, deltaM=0.2, Delta ε =1.0 PSH Deaggregation on NEHRP BC rock CWMNW_-_L14 120.200 Peak Horiz. Ground Accel.>=0.1819 g Ann. Exceedance Rate .405E-03. Mean Return Time 2475 years Mean (R,M, ε 50

250 0 200

9.0 200910 UPDATE

8.5 < 1

150 0 < 0.5 < 2 < 3 8.0 0 0 0 Closest Distance, Rcd (km) 0 < ε 1 < ε 7.5 0.5 < ε 2 < ε MAGNITUDE (Mw) 7.0 100

6.5 Distance (R), magnitude (M), epsilon (E0,E) deaggregation for a site on rock with average vs= 760. m/s top 30 m. USGS CGHT PSHA2008 UPDATE Bins lt 0.05% contrib. omitted < 0 0 < -1 <-0.5 6.0 0 0 50 < -2 0 -1 < ε -0.5 < ε 5.5 ε -2 < ε

Prob. SA, PGA median

10 8 6 4 2 5.0 % Contribution to Hazard to Contribution % 0 2010 Sep 28 17:13:17 GMT GALENA Version 5.02

Structural Fill

Liner Peak

Liner Post Peak

Sub Grade

1600

CWMNW - L14 Base Liner Revision

1400

1200

Waste

Structural Fill Liner System Analysis: 1 1000 Multiple Stability Analysis Method: Sarma Surface: Non-Circular

800 Results Critical (minimum) Factor of Safety: 2.55 Critical Acceleration (Kc): 0.962

600

Edited:9 Sep 2013 Processed: 9 Sep 2013

400 0 200 400 600 800 1000 1200 1400 1600

Project:CWMNW - L-14 Base Liner Revision - North South Section 1 Global Stability - North, Static File: Run 001 NS Facing N Static.gmf Licensed to: Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\Documents\EIL PROJECTS\Chem Waste\L-14 Expansion\2013\Slope Stability Gl...\Run 001 NS Facing N Static.gmf Processed: 09 Sep 2013 14:40:20 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Global Stability - North, Static

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (9 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (9 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (4 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 300.00 1170.00 1662.00 1170.00 Profile: 2 (11 points) Material beneath: 5 - Sub Grade 0.00 960.00 90.00 926.00 110.00 926.00 400.00 925.00 500.00 929.00 560.00 937.00 813.00 941.00 835.00 943.00 1400.00 935.00 1601.00 1002.00 1700.00 1002.00 Profile: 3 (3 points) Material beneath: 2 - Structural Fill 0.00 1015.00 325.00 1015.00 560.00 937.00 Profile: 4 (6 points) Material beneath: 4 - Liner Post Peak 355.00 1008.00 560.00 940.00 813.00 944.00 835.00 946.00 1400.00 938.00 1601.00 1005.00

Slope Surface (13 points) ------0.00 960.00 90.00 926.00 110.00 926.00 218.00 980.00 243.00 980.00 297.00 1007.00 355.00 1005.00 760.00 1140.00 920.00 1148.00 1021.00 1148.00 1183.00 1140.00 1601.00 1002.00 1700.00 1002.00

Piezometric Surfaces (1 surface) ------Surface within profile: 1 (4 points) - Waste 557.00 941.00 813.00 945.00 835.00 947.00 1402.30 939.00

Failure Surface ------Initial non-circular surface for critical search (20 points) 165.00 953.50 172.88 946.10 181.59 939.69 191.01 934.37 201.00 930.23 211.41 927.31 222.10 925.66 232.91 925.30 243.68 926.24 254.26 928.47 264.50 931.95 274.25 936.64 283.36 942.46 291.71 949.33 299.18 957.15 305.65 965.81 311.04 975.19 315.27 985.14 318.27 995.53 320.00 1006.21

Tension Crack ------Automatically-generated crack depth: 2.00

Variable Restraints ------Horizontal range around X-Left: 80.00 Trial positions within range: 41 Horizontal range around X-Right: 40.00 Trial positions within range: 21 Vertical range around Mid-Point: 20.00 Trial positions within range: 11

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Global Stability - North, Static

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Factor of Safety for initial failure surface approximation: 3.27

There were: 9466 successful analyses from a total of 9471 trial surfaces 5 analyses terminated due to unacceptable geometry

Critical (minimum) Factor of Safety: 2.55 —————————————————————————————————————————— Critical Acceleration (Kc): 0.962 Critical acceleration is outside the acceptable range of 0.0 ±1.0 - examine slice data and consult the Galena Users' Guide

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 205.00 973.50 313.51 1004.43 10.00 2.547 0.962 2 205.00 973.50 311.52 1004.50 10.00 2.551 0.543 3 205.00 973.50 315.50 1004.36 10.00 2.557 0.732 4 205.00 973.50 309.53 1004.57 10.00 2.563 0.584 5 205.00 973.50 317.49 1004.29 10.00 2.569 0.938 6 205.00 973.50 307.54 1004.64 10.00 2.570 0.608 7 203.00 972.50 311.53 1004.50 10.00 2.589 0.475 8 203.00 972.50 315.51 1004.36 10.00 2.590 0.500 9 205.00 973.50 319.48 1004.22 10.00 2.592 0.872 10 203.00 972.50 313.52 1004.43 10.00 2.593 0.507 11 205.00 973.50 305.55 1004.71 10.00 2.596 0.667 12 203.00 972.50 317.50 1004.29 10.00 2.603 0.501 13 203.00 972.50 309.54 1004.57 10.00 2.607 0.382 14 203.00 972.50 307.55 1004.64 10.00 2.611 -0.405 15 205.00 973.50 303.56 1004.77 10.00 2.612 0.676 16 205.00 973.50 321.47 1004.16 10.00 2.613 0.835 17 203.00 972.50 305.56 1004.70 10.00 2.619 2.004 18 201.00 971.50 317.51 1004.29 10.00 2.621 1.126 19 201.00 971.50 315.52 1004.36 10.00 2.624 0.887 20 203.00 972.50 319.49 1004.22 10.00 2.624 0.497 21 201.00 971.50 311.54 1004.50 10.00 2.627 0.879 22 201.00 971.50 309.55 1004.57 10.00 2.627 0.896 23 205.00 973.50 301.57 1004.84 10.00 2.630 0.694 24 201.00 971.50 307.56 1004.64 10.00 2.634 0.932 25 201.00 971.50 313.53 1004.43 10.00 2.635 0.886 26 203.00 972.50 303.57 1004.77 10.00 2.637 1.294 27 205.00 973.50 323.46 1004.09 10.00 2.638 0.824 28 201.00 971.50 319.50 1004.22 10.00 2.640 -0.295 29 201.00 971.50 305.57 1004.70 10.00 2.643 0.989 30 203.00 972.50 321.48 1004.16 10.00 2.644 0.490 31 205.00 973.50 313.54 1004.43 8.00 2.648 0.103 32 199.00 970.50 311.55 1004.50 10.00 2.650 0.279 33 205.00 973.50 311.55 1004.50 8.00 2.651 0.704 34 199.00 970.50 313.54 1004.43 10.00 2.652 0.797 35 199.00 970.50 317.52 1004.29 10.00 2.654 0.712 36 205.00 973.50 315.53 1004.36 8.00 2.655 -0.422 37 205.00 973.50 325.45 1004.02 10.00 2.655 0.716 38 203.00 972.50 301.58 1004.84 10.00 2.656 1.215 39 199.00 970.50 309.56 1004.57 10.00 2.657 0.432 40 201.00 971.50 321.49 1004.16 10.00 2.657 0.380 41 203.00 972.50 323.47 1004.09 10.00 2.658 0.451 42 199.00 970.50 315.53 1004.36 10.00 2.658 0.770 43 205.00 973.50 317.52 1004.29 8.00 2.663 1.994 44 201.00 971.50 303.58 1004.77 10.00 2.663 0.671 45 199.00 970.50 307.57 1004.64 10.00 2.663 0.433 46 199.00 970.50 319.51 1004.22 10.00 2.664 0.681 47 205.00 973.50 299.58 1004.91 10.00 2.665 0.709 48 205.00 973.50 309.56 1004.57 8.00 2.669 0.786 49 197.00 969.50 309.56 1004.57 10.00 2.669 0.298 50 197.00 969.50 311.56 1004.50 10.00 2.672 0.447 51 199.00 970.50 321.50 1004.16 10.00 2.672 0.632 52 199.00 970.50 305.57 1004.70 10.00 2.673 0.418 53 197.00 969.50 313.55 1004.43 10.00 2.674 0.468 54 201.00 971.50 323.48 1004.09 10.00 2.677 0.465 55 195.00 968.50 311.56 1004.50 10.00 2.679 0.518 56 205.00 973.50 327.43 1003.95 10.00 2.681 0.688 57 205.00 973.50 319.51 1004.22 8.00 2.683 1.479 58 197.00 969.50 315.54 1004.36 10.00 2.683 0.463 59 195.00 968.50 313.55 1004.43 10.00 2.684 0.429 60 197.00 969.50 317.53 1004.29 10.00 2.685 -0.630 61 203.00 972.50 325.46 1004.02 10.00 2.685 0.308 62 197.00 969.50 307.57 1004.64 10.00 2.687 1.020 63 203.00 972.50 315.54 1004.36 8.00 2.688 0.624 64 199.00 970.50 323.49 1004.09 10.00 2.690 0.607 65 203.00 972.50 311.56 1004.50 8.00 2.691 0.680 66 203.00 972.50 313.55 1004.43 8.00 2.692 0.665 67 195.00 968.50 315.55 1004.36 10.00 2.692 -0.263 68 203.00 972.50 299.59 1004.91 10.00 2.693 1.254 69 195.00 968.50 309.57 1004.57 10.00 2.696 0.577 70 197.00 969.50 319.52 1004.22 10.00 2.696 4.282 71 203.00 972.50 317.53 1004.29 8.00 2.698 0.610 72 205.00 973.50 307.57 1004.64 8.00 2.699 0.903 73 195.00 968.50 317.54 1004.29 10.00 2.700 0.895 74 197.00 969.50 321.51 1004.15 10.00 2.700 0.664 75 193.00 967.50 313.56 1004.43 10.00 2.700 0.511 76 205.00 973.50 329.42 1003.88 10.00 2.700 0.640 77 201.00 971.50 325.47 1004.02 10.00 2.700 0.491 78 205.00 973.50 321.50 1004.16 8.00 2.701 1.255 79 193.00 967.50 315.55 1004.36 10.00 2.702 0.443 80 197.00 969.50 305.58 1004.70 10.00 2.704 0.749 81 193.00 967.50 311.57 1004.50 10.00 2.704 0.555 82 199.00 970.50 303.58 1004.77 10.00 2.707 0.370 83 193.00 967.50 317.55 1004.29 10.00 2.708 0.351 84 205.00 973.50 305.58 1004.70 8.00 2.709 1.005 85 203.00 972.50 309.57 1004.57 8.00 2.710 0.699 86 195.00 968.50 319.53 1004.22 10.00 2.711 0.726 87 199.00 970.50 325.48 1004.02 10.00 2.711 0.576 88 191.00 966.50 317.55 1004.29 10.00 2.711 0.451 89 197.00 969.50 323.50 1004.09 10.00 2.714 0.634 90 201.00 971.50 301.58 1004.84 10.00 2.716 0.475 91 203.00 972.50 327.45 1003.95 10.00 2.716 -0.113 92 203.00 972.50 319.52 1004.22 8.00 2.717 0.597 93 191.00 966.50 315.56 1004.36 10.00 2.717 0.509 94 193.00 967.50 319.54 1004.22 10.00 2.718 0.123 95 191.00 966.50 313.57 1004.43 10.00 2.718 0.663 96 195.00 968.50 307.58 1004.64 10.00 2.718 0.632 97 201.00 971.50 315.55 1004.36 8.00 2.718 2.367 98 203.00 972.50 307.58 1004.64 8.00 2.719 0.561 99 193.00 967.50 309.58 1004.57 10.00 2.722 0.606 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (20 points), adjusted for tension crack ------205.00 973.50 210.54 970.50 216.67 968.06 223.29 966.22 230.32 964.98 237.64 964.36 245.15 964.34 252.76 964.92 260.33 966.08 267.77 967.80 274.97 970.03 281.83 972.76 288.23 975.93 294.11 979.49 299.36 983.40 303.91 987.60 307.70 992.06 310.67 996.71 312.78 1001.51 313.51 1004.43

Non-Vertical Slice Geometry (20 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 205.00 973.50 205.00 973.50 13.99 -28.5 5.54 6.30 0.0 0.00 2 209.85 975.92 210.54 970.50 45.63 -21.7 6.13 6.59 -7.3 5.47 3 215.14 978.57 216.67 968.06 36.51 -15.6 3.32 3.44 -8.2 10.62 4 218.00 980.00 219.98 967.14 41.33 -15.6 3.31 3.43 -8.8 13.02 5 221.04 980.00 223.29 966.22 96.07 -9.9 7.03 7.13 -9.3 13.97 6 227.57 980.00 230.32 964.98 107.95 -4.9 7.32 7.35 -10.4 15.26 7 234.46 980.00 237.64 964.36 125.66 -0.1 7.52 7.52 -11.5 15.96 8 243.00 980.00 245.15 964.34 113.74 4.4 7.60 7.62 -7.8 15.81 9 248.37 982.69 252.76 964.92 144.32 8.7 7.57 7.66 -13.9 18.30 10 254.97 985.98 260.33 966.08 158.98 13.0 7.44 7.64 -15.1 20.62 11 261.50 989.25 267.77 967.80 167.41 17.3 7.20 7.54 -16.3 22.35 12 267.91 992.45 274.97 970.03 169.40 21.7 6.86 7.38 -17.5 23.51 13 274.13 995.56 281.83 972.76 164.87 26.3 6.41 7.15 -18.7 24.07 14 280.10 998.55 288.23 975.93 154.74 31.2 5.87 6.87 -19.8 24.04 15 285.76 1001.38 294.11 979.49 139.58 36.6 5.25 6.55 -20.9 23.42 16 291.08 1004.04 299.36 983.40 132.05 42.7 4.55 6.20 -21.9 22.24 17 297.00 1007.00 303.91 987.60 82.88 49.6 3.79 5.85 -19.6 20.59 18 301.22 1006.85 307.70 992.06 61.26 57.4 2.97 5.52 -23.7 16.15 19 306.15 1006.68 310.67 996.71 32.00 66.3 2.11 5.24 -24.4 10.96 20 310.43 1006.54 312.78 1001.51 8.34 76.1 0.72 3.01 -25.1 5.55 RHS 313.51 1006.43 313.51 1004.43 ------0.0 2.00 X-S Area: 1996.71 Path Length: 125.99

Non-Vertical Slice Properties (20 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 0.00 32.5 0.00 0.0 1818.85 0.00 0.00 0.00 0.00 591.65 0.00 2 0.00 32.5 0.00 32.5 5931.86 0.00 0.00 0.00 0.00 1538.35 494.61 3 0.00 32.5 0.00 32.5 4746.54 0.00 0.00 0.00 0.00 2061.09 859.36 4 0.00 32.5 0.00 32.5 5373.16 0.00 0.00 0.00 0.00 2367.22 996.18 5 0.00 32.5 0.00 32.5 12489.22 0.00 0.00 0.00 0.00 2399.55 1245.14 6 0.00 32.5 0.00 32.5 14033.35 0.00 0.00 0.00 0.00 2438.52 1649.78 7 0.00 32.5 0.00 32.5 16335.84 0.00 0.00 0.00 0.00 2085.67 1996.37 8 0.00 32.5 0.00 32.5 14785.99 0.00 0.00 0.00 0.00 2710.56 2222.50 9 0.00 32.5 0.00 32.5 18761.79 0.00 0.00 0.00 0.00 2654.32 2231.61 10 0.00 32.5 0.00 32.5 20668.05 0.00 0.00 0.00 0.00 2796.27 2109.46 11 0.00 32.5 0.00 32.5 21763.32 0.00 0.00 0.00 0.00 2851.10 1989.85 12 0.00 32.5 0.00 32.5 22021.42 0.00 0.00 0.00 0.00 2823.01 1856.09 13 0.00 32.5 0.00 32.5 21433.43 0.00 0.00 0.00 0.00 2720.86 1699.72 14 0.00 32.5 0.00 32.5 20115.72 0.00 0.00 0.00 0.00 2551.65 1517.52 15 0.00 32.5 0.00 32.5 18145.47 0.00 0.00 0.00 0.00 2323.47 1308.07 16 0.00 32.5 0.00 32.5 17166.96 0.00 0.00 0.00 0.00 2094.47 1071.20 17 0.00 32.5 0.00 32.5 10774.08 0.00 0.00 0.00 0.00 1605.17 762.60 18 0.00 32.5 0.00 32.5 7963.71 0.00 0.00 0.00 0.00 1124.08 595.85 19 0.00 32.5 0.00 32.5 4160.14 0.00 0.00 0.00 0.00 623.13 391.92 20 0.00 32.5 0.00 32.5 1083.97 0.00 0.00 0.00 0.00 294.25 181.58 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 259572.86

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— GALENA Version 5.02

Structural Fill

Liner Peak

Liner Post Peak

Sub Grade 1400

CWMNW - L14 Base Liner Revision Module 4&5 1300

1200

1100 Waste - Module 5 Analysis:1 Multiple Stability Analysis Structural Fill 1000 Method:Sarma Liner System Surface:Non-Circular

Results 900 Critical (minimum) Factor of Safety: 1.95 Critical Acceleration (Kc):0.231

800

Edited:11 Sep 2013 Processed: 11 Sep 2013

0 100 200 300 400 500 600 700 800

Project:CWMNW - L-14 Base Liner Revision - North South Section 2 Global Stability - North, Static File: Run 002 NS Facing N Static 2GCL.gmf Licensed to:Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\DOCUME~1\EILPRO~1\CHEMWA~1\L-14EX~1\2013\SLOPES~2\Run 002 NS Facing N Static 2GCL.gmf Processed: 11 Sep 2013 12:00:42 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Global Stability - North, Static

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 22000.00 8000.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 22000.00 2800.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (4 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 300.00 1200.00 835.00 1200.00 Profile: 2 (8 points) Material beneath: 5 - Sub Grade 0.00 960.00 90.00 926.00 110.00 926.00 400.00 925.00 500.00 929.00 560.00 937.00 813.00 941.00 835.00 943.00 Profile: 3 (3 points) Material beneath: 2 - Structural Fill 0.00 1015.00 325.00 1015.00 560.00 937.00 Profile: 4 (4 points) Material beneath: 4 - Liner Post Peak 355.00 1008.00 560.00 940.00 813.00 944.00 835.00 946.00

Slope Surface (9 points) ------0.00 960.00 90.00 926.00 110.00 926.00 218.00 980.00 243.00 980.00 297.00 1007.00 355.00 1005.00 760.00 1140.00 835.00 1146.00

Piezometric Surfaces (1 surface) ------Surface within profile: 1 (3 points) - Waste 557.00 941.00 813.00 945.00 835.00 947.00

Failure Surface ------Initial non-circular surface for critical search (4 points) 357.22 1005.74 560.00 938.50 650.00 940.00 776.38 1141.31

Tension Crack ------Automatically-generated crack depth: 2.00

Variable Restraints ------Horizontal range around X-Left: 5.00 Trial positions within range: 5 Horizontal range around X-Right: 80.00 Trial positions within range: 80 Vertical range around Mid-Point: 3.00 Trial positions within range: 2

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Global Stability - North, Static

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Factor of Safety for initial failure surface approximation: 1.98

There were: 801 successful analyses from a total of 801 trial surfaces

Critical (minimum) Factor of Safety: 1.95 —————————————————————————————————————————— Critical Acceleration (Kc): 0.231

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 355.97 1005.32 784.64 1139.97 1.50 1.947 0.231 2 355.97 1005.32 783.63 1139.89 1.50 1.949 0.232 3 355.97 1005.32 782.62 1139.81 1.50 1.951 0.233 4 358.47 1006.16 790.72 1140.46 -1.50 1.951 0.230 5 354.72 1005.01 789.69 1140.38 1.50 1.952 0.236 6 358.47 1006.16 789.71 1140.38 -1.50 1.952 0.231 7 355.97 1005.32 781.61 1139.73 1.50 1.952 0.234 8 354.72 1005.01 788.68 1140.29 1.50 1.953 0.236 9 355.97 1005.32 780.60 1139.65 1.50 1.954 0.235 10 358.47 1006.16 788.70 1140.30 -1.50 1.954 0.232 11 354.72 1005.01 787.67 1140.21 1.50 1.954 0.237 12 355.97 1005.32 779.59 1139.57 1.50 1.955 0.236 13 358.47 1006.16 787.69 1140.22 -1.50 1.955 0.232 14 354.72 1005.01 786.66 1140.13 1.50 1.956 0.238 15 355.97 1005.32 778.58 1139.49 1.50 1.957 0.236 16 358.47 1006.16 786.68 1140.13 -1.50 1.957 0.233 17 354.72 1005.01 785.65 1140.05 1.50 1.957 0.239 18 355.97 1005.32 777.57 1139.41 1.50 1.959 0.237 19 358.47 1006.16 785.67 1140.05 -1.50 1.959 0.234 20 354.72 1005.01 784.64 1139.97 1.50 1.959 0.239 21 355.97 1005.32 776.56 1139.32 1.50 1.960 0.238 22 358.47 1006.16 784.66 1139.97 -1.50 1.960 0.235 23 354.72 1005.01 783.63 1139.89 1.50 1.960 0.240 24 355.97 1005.32 775.55 1139.24 1.50 1.962 0.239 25 354.72 1005.01 782.62 1139.81 1.50 1.962 0.241 26 358.47 1006.16 783.65 1139.89 -1.50 1.962 0.236 27 355.97 1005.32 774.54 1139.16 1.50 1.964 0.239 28 358.47 1006.16 782.64 1139.81 -1.50 1.964 0.236 29 355.97 1005.32 773.53 1139.08 1.50 1.965 0.240 30 358.47 1006.16 781.63 1139.73 -1.50 1.966 0.237 31 355.97 1005.32 772.52 1139.00 1.50 1.967 0.241 32 358.47 1006.16 780.62 1139.65 -1.50 1.968 0.238 33 355.97 1005.32 771.51 1138.92 1.50 1.969 0.242 34 358.47 1006.16 779.61 1139.57 -1.50 1.973 0.239 35 355.97 1005.32 770.50 1138.84 1.50 1.974 0.242 36 357.22 1005.74 776.56 1139.32 1.50 1.974 0.240 37 358.47 1006.16 778.60 1139.49 -1.50 1.975 0.240 38 355.97 1005.32 769.49 1138.76 1.50 1.976 0.243 39 357.22 1005.74 775.55 1139.24 1.50 1.976 0.241 40 357.22 1005.74 778.60 1139.49 -1.50 1.976 0.244 41 358.47 1006.16 777.59 1139.41 -1.50 1.976 0.241 42 354.72 1005.01 790.70 1140.46 1.50 1.977 0.246 43 355.97 1005.32 768.48 1138.68 1.50 1.977 0.244 44 357.22 1005.74 774.54 1139.16 1.50 1.977 0.242 45 357.22 1005.74 777.59 1139.41 -1.50 1.978 0.245 46 355.97 1005.32 767.47 1138.60 1.50 1.978 0.244 47 358.47 1006.16 776.58 1139.33 -1.50 1.978 0.242 48 357.22 1005.74 776.58 1139.33 -1.50 1.980 0.246 49 355.97 1005.32 766.46 1138.52 1.50 1.980 0.245 50 358.47 1006.16 775.57 1139.25 -1.50 1.980 0.243 51 357.22 1005.74 775.57 1139.25 -1.50 1.981 0.247 52 355.97 1005.32 765.45 1138.44 1.50 1.981 0.246 53 358.47 1006.16 774.56 1139.16 -1.50 1.981 0.244 54 357.22 1005.74 774.56 1139.16 -1.50 1.982 0.247 55 355.97 1005.32 764.44 1138.35 1.50 1.983 0.246 56 358.47 1006.16 773.55 1139.08 -1.50 1.983 0.244 57 357.22 1005.74 775.05 1139.20 0.00 1.984 0.245 58 354.72 1005.01 781.61 1139.73 1.50 1.984 0.251 59 355.97 1005.32 763.43 1138.27 1.50 1.984 0.247 60 357.22 1005.74 773.55 1139.08 -1.50 1.984 0.248 61 358.47 1006.16 772.54 1139.00 -1.50 1.985 0.245 62 354.72 1005.01 780.60 1139.65 1.50 1.985 0.252 63 355.97 1005.32 762.42 1138.19 1.50 1.986 0.248 64 354.72 1005.01 779.59 1139.57 1.50 1.986 0.253 65 354.72 1005.01 778.58 1139.49 1.50 1.988 0.254 66 354.72 1005.01 777.57 1139.41 1.50 1.993 0.254 67 355.97 1005.32 785.65 1140.05 1.50 1.995 0.254 68 357.22 1005.74 777.57 1139.41 1.50 1.995 0.251 69 354.72 1005.01 791.71 1140.54 1.50 1.996 0.257 70 358.47 1006.16 771.53 1138.92 -1.50 1.997 0.247 71 358.47 1006.16 770.52 1138.84 -1.50 2.000 0.250 72 358.47 1006.16 769.51 1138.76 -1.50 2.000 0.251 73 358.47 1006.16 768.50 1138.68 -1.50 2.000 0.251 74 358.47 1006.16 767.49 1138.60 -1.50 2.000 0.252 75 354.72 1005.01 776.56 1139.32 1.50 2.000 0.265 76 358.47 1006.16 766.48 1138.52 -1.50 2.010 0.253 77 354.72 1005.01 775.55 1139.24 1.50 2.012 0.265 78 354.72 1005.01 774.54 1139.16 1.50 2.015 0.266 79 355.97 1005.32 761.41 1138.11 1.50 2.017 0.254 80 357.22 1005.74 772.54 1139.00 -1.50 2.031 0.274 81 357.22 1005.74 773.53 1139.08 1.50 2.036 0.254 82 358.47 1006.16 765.47 1138.44 -1.50 2.036 0.266 83 354.72 1005.01 773.53 1139.08 1.50 2.038 0.279 84 355.97 1005.32 786.66 1140.13 1.50 2.039 0.278 85 354.72 1005.01 772.52 1139.00 1.50 2.040 0.280 86 354.72 1005.01 792.72 1140.62 1.50 2.042 0.282 87 359.72 1006.57 764.46 1138.36 -1.50 2.055 0.270 88 359.72 1006.57 763.45 1138.28 -1.50 2.057 0.271 89 359.72 1006.57 762.44 1138.19 -1.50 2.060 0.271 90 359.72 1006.57 761.43 1138.11 -1.50 2.062 0.272 91 359.72 1006.57 760.42 1138.03 -1.50 2.064 0.273 92 354.72 1005.01 794.74 1140.78 1.50 2.065 0.300 93 359.72 1006.57 769.51 1138.76 -1.50 2.066 0.276 94 354.72 1005.01 793.73 1140.70 1.50 2.066 0.295 95 359.72 1006.57 759.29 1137.76 -1.50 2.067 0.274 96 354.72 1005.01 771.51 1138.92 1.50 2.067 0.294 97 359.72 1006.57 768.50 1138.68 -1.50 2.068 0.277 98 359.72 1006.57 767.49 1138.60 -1.50 2.070 0.277 99 359.72 1006.57 766.48 1138.52 -1.50 2.073 0.278 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (4 points), adjusted for tension crack ------355.97 1005.32 564.01 938.74 656.34 940.38 784.64 1139.97

Non-Vertical Slice Geometry (4 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 355.97 1005.32 355.97 1005.32 11773.06 -17.7 208.04 218.43 0.0 0.00 2 529.19 1063.06 564.01 938.74 12041.91 1.0 92.33 92.35 -15.6 129.11 3 605.20 1088.40 656.34 940.38 14968.43 57.3 114.29 211.36 -19.1 156.61 4 760.00 1140.00 770.63 1118.18 293.36 57.3 14.01 25.91 -26.0 24.28 RHS 784.64 1141.97 784.64 1139.97 ------0.0 2.00 X-S Area: 39076.75 Path Length: 548.06

Non-Vertical Slice Properties (4 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 273.49 8.3 0.00 0.0 1284408.25 0.00 0.00 0.00 0.00 8881.71 0.00 2 547.58 5.8 7.16 32.7 1319474.00 0.00 0.00 0.00 4169.59 15654.32 6701.53 3 0.00 33.0 4.35 32.8 1646527.38 0.00 0.00 25.41 4989.72 5895.51 6347.52 4 0.00 33.0 0.00 33.0 32269.25 0.00 0.00 0.00 0.00 848.62 793.64 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 4282679.00

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— GALENA Version 5.02

Structural Fill

Liner Peak

Liner Post Peak

0.182 Sub Grade

1600

CWMNW - L14 Base Liner Revision

1400

1200

Waste

Structural Fill Liner System Analysis: 1 1000 Multiple Stability Analysis Method: Sarma Surface: Non-Circular

800 Results Critical (minimum) Factor of Safety: 1.66 Critical Acceleration (Kc): 0.458

600

Edited:9 Sep 2013 Processed: 9 Sep 2013

400 0 200 400 600 800 1000 1200 1400 1600

Project:CWMNW - L-14 Base Liner Revision - North South Section 3 Global Stability - North, EQ File: Run 003 NS Facing N EQ.gmf Licensed to: Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\Documents\EIL PROJECTS\Chem Waste\L-14 Expansion\2013\Slope Stability Global...\Run 003 NS Facing N EQ.gmf Processed: 09 Sep 2013 14:42:52 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Global Stability - North, EQ

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 22000.00 8000.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 22000.00 2800.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (4 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 300.00 1170.00 1662.00 1170.00 Profile: 2 (11 points) Material beneath: 5 - Sub Grade 0.00 960.00 90.00 926.00 110.00 926.00 400.00 925.00 500.00 929.00 560.00 937.00 813.00 941.00 835.00 943.00 1400.00 935.00 1601.00 1002.00 1700.00 1002.00 Profile: 3 (3 points) Material beneath: 2 - Structural Fill 0.00 1015.00 325.00 1015.00 560.00 937.00 Profile: 4 (6 points) Material beneath: 4 - Liner Post Peak 355.00 1008.00 560.00 940.00 813.00 944.00 835.00 946.00 1400.00 938.00 1601.00 1005.00

Slope Surface (13 points) ------0.00 960.00 90.00 926.00 110.00 926.00 218.00 980.00 243.00 980.00 297.00 1007.00 355.00 1005.00 760.00 1140.00 920.00 1148.00 1021.00 1148.00 1183.00 1140.00 1601.00 1002.00 1700.00 1002.00

Piezometric Surfaces (1 surface) ------Surface within profile: 1 (4 points) - Waste 557.00 941.00 813.00 945.00 835.00 947.00 1402.30 939.00

Failure Surface ------Initial non-circular surface for critical search (20 points) 165.00 953.50 172.88 946.10 181.59 939.69 191.01 934.37 201.00 930.23 211.41 927.31 222.10 925.66 232.91 925.30 243.68 926.24 254.26 928.47 264.50 931.95 274.25 936.64 283.36 942.46 291.71 949.33 299.18 957.15 305.65 965.81 311.04 975.19 315.27 985.14 318.27 995.53 320.00 1006.21

Earthquake Force ------Pseudo-static earthquake (seismic) coefficient: 0.182

Tension Crack ------Automatically-generated crack depth: 2.00

Variable Restraints ------Horizontal range around X-Left: 80.00 Trial positions within range: 41 Horizontal range around X-Right: 40.00 Trial positions within range: 21 Vertical range around Mid-Point: 20.00 Trial positions within range: 11

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Global Stability - North, EQ

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Factor of Safety for initial failure surface approximation: 2.29

There were: 9379 successful analyses from a total of 9471 trial surfaces 5 analyses terminated due to unacceptable geometry 87 analyses that failed to produce a result

Critical (minimum) Factor of Safety: 1.66 —————————————————————————————————————————— Critical Acceleration (Kc): 0.458 Critical acceleration is outside the acceptable range of 0.0 ±1.0 - examine slice data and consult the Galena Users' Guide

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 205.00 973.50 329.42 1003.88 10.00 1.656 0.458 2 205.00 973.50 325.45 1004.02 10.00 1.659 0.534 3 205.00 973.50 327.43 1003.95 10.00 1.660 0.506 4 205.00 973.50 331.41 1003.81 10.00 1.663 0.444 5 205.00 973.50 319.48 1004.22 10.00 1.664 0.690 6 205.00 973.50 317.49 1004.29 10.00 1.665 0.756 7 205.00 973.50 321.47 1004.16 10.00 1.666 0.653 8 205.00 973.50 333.40 1003.74 10.00 1.669 0.428 9 205.00 973.50 323.46 1004.09 10.00 1.670 0.642 10 205.00 973.50 315.50 1004.36 10.00 1.675 0.550 11 205.00 973.50 335.39 1003.68 10.00 1.676 0.417 12 203.00 972.50 329.44 1003.88 10.00 1.680 0.497 13 205.00 973.50 313.51 1004.43 10.00 1.680 0.780 14 203.00 972.50 331.43 1003.81 10.00 1.683 0.471 15 205.00 973.50 337.38 1003.61 10.00 1.684 0.402 16 203.00 972.50 323.47 1004.09 10.00 1.684 0.269 17 203.00 972.50 335.41 1003.68 10.00 1.685 0.407 18 203.00 972.50 325.46 1004.02 10.00 1.687 0.126 19 203.00 972.50 333.42 1003.74 10.00 1.687 0.447 20 203.00 972.50 327.45 1003.95 10.00 1.690 -0.295 21 205.00 973.50 339.37 1003.54 10.00 1.693 0.362 22 203.00 972.50 337.40 1003.61 10.00 1.693 0.392 23 201.00 971.50 321.49 1004.16 10.00 1.698 0.198 24 203.00 972.50 319.49 1004.22 10.00 1.700 0.315 25 203.00 972.50 317.50 1004.29 10.00 1.700 0.319 26 203.00 972.50 339.39 1003.54 10.00 1.700 0.377 27 203.00 972.50 321.48 1004.16 10.00 1.701 0.308 28 203.00 972.50 315.51 1004.36 10.00 1.702 0.318 29 201.00 971.50 319.50 1004.22 10.00 1.702 -0.477 30 201.00 971.50 323.48 1004.09 10.00 1.702 0.283 31 201.00 971.50 317.51 1004.29 10.00 1.706 0.944 32 201.00 971.50 325.47 1004.02 10.00 1.707 0.309 33 201.00 971.50 335.42 1003.68 10.00 1.708 0.798 34 199.00 970.50 323.49 1004.09 10.00 1.709 0.425 35 199.00 970.50 321.50 1004.16 10.00 1.710 0.450 36 201.00 971.50 327.46 1003.95 10.00 1.711 0.313 37 199.00 970.50 325.48 1004.02 10.00 1.711 0.394 38 201.00 971.50 337.41 1003.61 10.00 1.712 0.607 39 201.00 971.50 339.40 1003.54 10.00 1.712 0.496 40 199.00 970.50 327.47 1003.95 10.00 1.713 0.336 41 205.00 973.50 311.52 1004.50 10.00 1.714 0.361 42 203.00 972.50 313.52 1004.43 10.00 1.715 0.325 43 199.00 970.50 329.46 1003.88 10.00 1.715 0.121 44 201.00 971.50 329.45 1003.88 10.00 1.715 0.308 45 201.00 971.50 333.43 1003.74 10.00 1.716 -0.071 46 205.00 973.50 331.45 1003.81 8.00 1.718 0.679 47 197.00 969.50 325.49 1004.02 10.00 1.719 0.405 48 197.00 969.50 327.48 1003.95 10.00 1.720 0.378 49 201.00 971.50 331.44 1003.81 10.00 1.720 0.274 50 201.00 971.50 315.52 1004.36 10.00 1.720 0.705 51 205.00 973.50 325.48 1004.02 8.00 1.720 0.827 52 205.00 973.50 327.47 1003.95 8.00 1.720 0.765 53 199.00 970.50 319.51 1004.22 10.00 1.721 0.499 54 197.00 969.50 329.47 1003.88 10.00 1.722 0.341 55 205.00 973.50 329.46 1003.88 8.00 1.722 0.726 56 205.00 973.50 333.44 1003.74 8.00 1.722 0.698 57 203.00 972.50 311.53 1004.50 10.00 1.724 0.293 58 197.00 969.50 331.47 1003.81 10.00 1.725 0.291 59 199.00 970.50 331.45 1003.81 10.00 1.726 1.256 60 197.00 969.50 333.46 1003.74 10.00 1.726 0.199 61 199.00 970.50 333.44 1003.74 10.00 1.727 0.724 62 199.00 970.50 317.52 1004.29 10.00 1.727 0.530 63 197.00 969.50 323.50 1004.09 10.00 1.727 0.452 64 205.00 973.50 335.43 1003.67 8.00 1.729 0.798 65 195.00 968.50 329.49 1003.88 10.00 1.729 0.380 66 205.00 973.50 309.53 1004.57 10.00 1.729 0.402 67 197.00 969.50 321.51 1004.15 10.00 1.731 0.482 68 205.00 973.50 321.50 1004.16 8.00 1.731 1.073 69 205.00 973.50 319.51 1004.22 8.00 1.732 1.297 70 205.00 973.50 323.49 1004.09 8.00 1.732 0.961 71 195.00 968.50 331.48 1003.81 10.00 1.732 0.352 72 197.00 969.50 335.45 1003.67 10.00 1.733 -0.066 73 199.00 970.50 335.43 1003.67 10.00 1.733 0.733 74 195.00 968.50 333.47 1003.74 10.00 1.734 0.317 75 199.00 970.50 339.42 1003.54 10.00 1.735 0.054 76 199.00 970.50 337.43 1003.61 10.00 1.735 1.298 77 203.00 972.50 329.47 1003.88 8.00 1.738 0.708 78 205.00 973.50 317.52 1004.29 8.00 1.739 1.812 79 197.00 969.50 337.44 1003.61 10.00 1.739 -6.479 80 201.00 971.50 313.53 1004.43 10.00 1.739 0.704 81 203.00 972.50 335.45 1003.67 8.00 1.739 0.538 82 203.00 972.50 331.46 1003.81 8.00 1.740 0.650 83 195.00 968.50 335.46 1003.67 10.00 1.740 0.263 84 205.00 973.50 307.54 1004.64 10.00 1.741 0.426 85 205.00 973.50 339.41 1003.54 8.00 1.741 -0.045 86 205.00 973.50 337.42 1003.61 8.00 1.741 1.744 87 203.00 972.50 333.46 1003.74 8.00 1.742 0.605 88 199.00 970.50 315.53 1004.36 10.00 1.742 0.588 89 195.00 968.50 327.49 1003.95 10.00 1.742 0.585 90 195.00 968.50 325.50 1004.02 10.00 1.744 0.771 91 203.00 972.50 337.44 1003.61 8.00 1.744 0.514 92 203.00 972.50 309.54 1004.57 10.00 1.745 0.200 93 195.00 968.50 337.45 1003.61 10.00 1.745 0.159 94 201.00 971.50 311.54 1004.50 10.00 1.746 0.697 95 193.00 967.50 333.48 1003.74 10.00 1.747 0.402 96 205.00 973.50 315.53 1004.36 8.00 1.747 -0.604 97 199.00 970.50 313.54 1004.43 10.00 1.747 0.615 98 195.00 968.50 339.44 1003.54 10.00 1.748 -0.179 99 193.00 967.50 335.47 1003.67 10.00 1.748 0.331 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (20 points), adjusted for tension crack ------205.00 973.50 211.35 970.57 218.38 968.20 225.98 966.42 234.03 965.23 242.43 964.63 251.05 964.63 259.77 965.21 268.45 966.36 276.98 968.06 285.24 970.26 293.10 972.94 300.45 976.05 307.19 979.54 313.21 983.36 318.43 987.48 322.77 991.83 326.19 996.37 328.60 1001.07 329.42 1003.88

Non-Vertical Slice Geometry (19 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 205.00 973.50 205.00 973.50 17.79 -24.7 6.35 7.00 0.0 0.00 2 210.83 976.41 211.35 970.57 62.86 -18.6 7.02 7.41 -5.2 5.86 3 218.00 980.00 218.38 968.20 86.99 -13.3 7.60 7.80 -1.8 11.80 4 224.26 980.00 225.98 966.42 109.93 -8.4 8.06 8.14 -7.2 13.69 5 231.87 980.00 234.03 965.23 146.86 -4.1 8.40 8.42 -8.3 14.93 6 243.00 980.00 242.43 964.63 111.86 0.0 8.62 8.62 2.1 15.38 7 247.70 982.35 251.05 964.63 166.73 3.8 8.72 8.74 -10.7 18.03 8 255.34 986.17 259.77 965.21 193.66 7.5 8.69 8.76 -11.9 21.42 9 262.94 989.97 268.45 966.36 213.50 11.2 8.53 8.70 -13.1 24.24 10 270.41 993.71 276.98 968.06 225.47 14.9 8.26 8.55 -14.4 26.48 11 277.69 997.35 285.24 970.26 229.23 18.8 7.86 8.31 -15.6 28.12 12 284.71 1000.85 293.10 972.94 224.63 22.9 7.35 7.98 -16.7 29.15 13 291.38 1004.19 300.45 976.05 202.07 27.4 6.73 7.58 -17.9 29.57 14 297.00 1007.00 307.19 979.54 191.57 32.4 6.02 7.14 -20.3 29.29 15 304.74 1006.73 313.21 983.36 138.94 38.3 5.22 6.64 -19.9 24.86 16 311.19 1006.51 318.43 987.48 98.86 45.1 4.35 6.15 -20.8 20.36 17 317.04 1006.31 322.77 991.83 62.46 53.1 3.41 5.68 -21.6 15.57 18 322.18 1006.13 326.19 996.37 31.73 62.7 2.42 5.28 -22.3 10.55 19 326.53 1005.98 328.60 1001.07 7.83 73.8 0.82 2.93 -22.9 5.34 RHS 329.42 1005.88 329.42 1003.88 ------0.0 2.00 X-S Area: 2522.97 Path Length: 139.83

Non-Vertical Slice Properties (19 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 0.00 32.5 0.00 0.0 2312.23 0.00 -420.83 0.00 0.00 814.15 0.00 2 0.00 32.5 0.00 32.5 8172.27 0.00 -1487.35 0.00 0.00 1830.47 701.27 3 0.00 32.5 0.00 32.5 11309.34 0.00 -2058.30 0.00 0.00 2639.97 1009.06 4 0.00 32.5 0.00 32.5 14290.66 0.00 -2600.90 0.00 0.00 2582.68 1713.21 5 0.00 32.5 0.00 32.5 19092.13 0.00 -3474.77 0.00 0.00 1629.52 2196.62 6 0.00 32.5 0.00 32.5 14541.55 0.00 -2646.56 0.00 0.00 3367.15 2142.41 7 0.00 32.5 0.00 32.5 21674.48 0.00 -3944.76 0.00 0.00 2852.90 2551.36 8 0.00 32.5 0.00 32.5 25175.81 0.00 -4582.00 0.00 0.00 3075.96 2383.81 9 0.00 32.5 0.00 32.5 27755.34 0.00 -5051.47 0.00 0.00 3190.86 2237.97 10 0.00 32.5 0.00 32.5 29311.22 0.00 -5334.64 0.00 0.00 3210.43 2081.17 11 0.00 32.5 0.00 32.5 29799.89 0.00 -5423.58 0.00 0.00 3140.37 1899.44 12 0.00 32.5 0.00 32.5 29201.62 0.00 -5314.70 0.00 0.00 2993.92 1685.89 13 0.00 32.5 0.00 32.5 26269.06 0.00 -4780.97 0.00 0.00 2785.16 1439.06 14 0.00 32.5 0.00 32.5 24903.52 0.00 -4532.44 0.00 0.00 2340.11 1198.09 15 0.00 32.5 0.00 32.5 18062.73 0.00 -3287.42 0.00 0.00 1806.23 1002.48 16 0.00 32.5 0.00 32.5 12851.62 0.00 -2339.00 0.00 0.00 1299.34 805.08 17 0.00 32.5 0.00 32.5 8119.58 0.00 -1477.76 0.00 0.00 839.86 592.12 18 0.00 32.5 0.00 32.5 4125.02 0.00 -750.75 0.00 0.00 441.26 374.83 19 0.00 32.5 0.00 32.5 1018.38 0.00 -185.34 0.00 0.00 194.83 163.23 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 327986.50

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— GALENA Version 5.02

Structural Fill

Liner Peak

Liner Post Peak

0.182 Sub Grade 1400

1300 CWMNW - L14 Base Liner Revision Module 4&5

1200

1100 Waste - Module 5 Analysis:1 Multiple Stability Analysis Structural Fill 1000 Method:Sarma Liner System Surface:Non-Circular

Results 900 Critical (minimum) Factor of Safety: 1.11 Critical Acceleration (Kc):0.048

800

Edited:11 Sep 2013 Processed: 11 Sep 2013

0 100 200 300 400 500 600 700 800

Project:CWMNW - L-14 Base Liner Revision - North South Section 4 Global Stability - North,Earthquake File: Run 004 NS Facing N EQ 2GCL.gmf Licensed to:Environmental Information Logistics, LLC. Galena 5.02 Analysis Results Licensee: Environmental Information Logistics, LLC. ———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— Project: CWMNW - L-14 Base Liner Revision - North South Section File: C:\Users\Dirk\Documents\EIL PROJECTS\Chem Waste\L-14 Expansion\2013\Slope Stability G...\Run 004 NS Facing N EQ 2GCL.gmf Processed: 11 Sep 2013 12:01:47 ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————

DATA: Analysis 1 - Global Stability - North,Earthquake

Material Properties (5 materials) ------Material: 1 (Mohr-Coulomb Isotropic) - Waste Cohesion Phi UnitWeight Ru 0.00 33.0 110.00 1.10 Material: 2 (Mohr-Coulomb Isotropic) - Structural Fill Cohesion Phi UnitWeight Ru 0.00 32.5 130.00 1.10 Material: 3 (Shear/Normal) - Liner Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 63.00 300.00 151.00 500.00 234.00 1000.00 383.00 5000.00 2228.00 10000.00 4063.00 14000.00 5110.00 18000.00 6727.00 22000.00 8000.00 Material: 4 (Shear/Normal) - Liner Post Peak UnitWeight Ru 65.00 1.10 Envelope Data (10 points) 0.00 0.00 100.00 42.00 300.00 96.00 500.00 173.00 1000.00 293.00 5000.00 868.00 10000.00 1600.00 14000.00 1970.00 18000.00 2375.00 22000.00 2800.00 Material: 5 (Mohr-Coulomb Isotropic) - Sub Grade Cohesion Phi UnitWeight Ru 500.00 30.0 130.00 1.10

Water Properties ------Unit weight of water: 62.400 Unit weight of water/medium above ground: 62.400

Material Profiles (4 profiles) ------Profile: 1 (2 points) Material beneath: 1 - Waste 300.00 1200.00 835.00 1200.00 Profile: 2 (8 points) Material beneath: 5 - Sub Grade 0.00 960.00 90.00 926.00 110.00 926.00 400.00 925.00 500.00 929.00 560.00 937.00 813.00 941.00 835.00 943.00 Profile: 3 (3 points) Material beneath: 2 - Structural Fill 0.00 1015.00 325.00 1015.00 560.00 937.00 Profile: 4 (4 points) Material beneath: 4 - Liner Post Peak 355.00 1008.00 560.00 940.00 813.00 944.00 835.00 946.00

Slope Surface (9 points) ------0.00 960.00 90.00 926.00 110.00 926.00 218.00 980.00 243.00 980.00 297.00 1007.00 355.00 1005.00 760.00 1140.00 835.00 1146.00

Piezometric Surfaces (1 surface) ------Surface within profile: 1 (3 points) - Waste 557.00 941.00 813.00 945.00 835.00 947.00

Failure Surface ------Initial non-circular surface for critical search (4 points) 357.22 1005.74 560.00 938.50 650.00 940.00 776.38 1141.31

Earthquake Force ------Pseudo-static earthquake (seismic) coefficient: 0.182

Tension Crack ------Automatically-generated crack depth: 2.00

Variable Restraints ------Horizontal range around X-Left: 5.00 Trial positions within range: 5 Horizontal range around X-Right: 80.00 Trial positions within range: 80 Vertical range around Mid-Point: 3.00 Trial positions within range: 2

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

RESULTS: Analysis 1 - Global Stability - North,Earthquake

Sarma Non-Vertical Slice Method of Analysis - Non-Circular Failure Surface ------Critical Failure Surface Search using Multiple Surface Generation Techniques

Factor of Safety for initial failure surface approximation: 1.14

There were: 801 successful analyses from a total of 801 trial surfaces

Critical (minimum) Factor of Safety: 1.11 —————————————————————————————————————————— Critical Acceleration (Kc): 0.048

Surface and Results Summary (Lowest 99 Factor of Safety surfaces) ------Surface X-Left Y-Left X-Right Y-Right Y-Deflection FoS Kc 1 358.47 1006.16 790.72 1140.46 -1.50 1.111 0.048 2 358.47 1006.16 789.71 1140.38 -1.50 1.113 0.049 3 355.97 1005.32 784.64 1139.97 1.50 1.113 0.049 4 358.47 1006.16 788.70 1140.30 -1.50 1.115 0.050 5 355.97 1005.32 783.63 1139.89 1.50 1.115 0.050 6 358.47 1006.16 787.69 1140.22 -1.50 1.116 0.050 7 355.97 1005.32 782.62 1139.81 1.50 1.116 0.051 8 358.47 1006.16 786.68 1140.13 -1.50 1.118 0.051 9 355.97 1005.32 781.61 1139.73 1.50 1.118 0.052 10 358.47 1006.16 785.67 1140.05 -1.50 1.120 0.052 11 355.97 1005.32 780.60 1139.65 1.50 1.120 0.053 12 358.47 1006.16 784.66 1139.97 -1.50 1.121 0.053 13 354.72 1005.01 789.69 1140.38 1.50 1.121 0.054 14 355.97 1005.32 779.59 1139.57 1.50 1.122 0.054 15 354.72 1005.01 788.68 1140.29 1.50 1.123 0.054 16 358.47 1006.16 783.65 1139.89 -1.50 1.123 0.054 17 355.97 1005.32 778.58 1139.49 1.50 1.123 0.054 18 354.72 1005.01 787.67 1140.21 1.50 1.124 0.055 19 358.47 1006.16 782.64 1139.81 -1.50 1.125 0.054 20 355.97 1005.32 777.57 1139.41 1.50 1.125 0.055 21 354.72 1005.01 786.66 1140.13 1.50 1.126 0.056 22 358.47 1006.16 781.63 1139.73 -1.50 1.127 0.055 23 355.97 1005.32 776.56 1139.32 1.50 1.127 0.056 24 354.72 1005.01 785.65 1140.05 1.50 1.128 0.057 25 355.97 1005.32 775.55 1139.24 1.50 1.128 0.057 26 358.47 1006.16 780.62 1139.65 -1.50 1.128 0.056 27 354.72 1005.01 784.64 1139.97 1.50 1.129 0.057 28 355.97 1005.32 774.54 1139.16 1.50 1.130 0.057 29 358.47 1006.16 779.61 1139.57 -1.50 1.130 0.057 30 354.72 1005.01 783.63 1139.89 1.50 1.131 0.058 31 357.22 1005.74 776.56 1139.32 1.50 1.131 0.058 32 355.97 1005.32 773.53 1139.08 1.50 1.131 0.058 33 358.47 1006.16 778.60 1139.49 -1.50 1.132 0.058 34 354.72 1005.01 782.62 1139.81 1.50 1.132 0.059 35 355.97 1005.32 772.52 1139.00 1.50 1.133 0.059 36 357.22 1005.74 775.55 1139.24 1.50 1.133 0.059 37 358.47 1006.16 777.59 1139.41 -1.50 1.134 0.059 38 355.97 1005.32 771.51 1138.92 1.50 1.135 0.060 39 357.22 1005.74 774.54 1139.16 1.50 1.135 0.060 40 358.47 1006.16 776.58 1139.33 -1.50 1.136 0.060 41 355.97 1005.32 770.50 1138.84 1.50 1.136 0.060 42 355.97 1005.32 769.49 1138.76 1.50 1.137 0.061 43 358.47 1006.16 775.57 1139.25 -1.50 1.138 0.061 44 355.97 1005.32 768.48 1138.68 1.50 1.139 0.062 45 358.47 1006.16 774.56 1139.16 -1.50 1.140 0.062 46 357.22 1005.74 778.60 1139.49 -1.50 1.140 0.062 47 355.97 1005.32 767.47 1138.60 1.50 1.140 0.062 48 354.72 1005.01 790.70 1140.46 1.50 1.140 0.064 49 355.97 1005.32 765.45 1138.44 1.50 1.141 0.064 50 357.22 1005.74 776.58 1139.33 -1.50 1.141 0.064 51 358.47 1006.16 773.55 1139.08 -1.50 1.141 0.062 52 357.22 1005.74 775.05 1139.20 0.00 1.141 0.063 53 357.22 1005.74 777.59 1139.41 -1.50 1.142 0.063 54 355.97 1005.32 766.46 1138.52 1.50 1.142 0.063 55 355.97 1005.32 764.44 1138.35 1.50 1.142 0.064 56 357.22 1005.74 775.57 1139.25 -1.50 1.143 0.065 57 358.47 1006.16 772.54 1139.00 -1.50 1.143 0.063 58 355.97 1005.32 763.43 1138.27 1.50 1.144 0.065 59 357.22 1005.74 774.56 1139.16 -1.50 1.144 0.065 60 358.47 1006.16 771.53 1138.92 -1.50 1.145 0.065 61 355.97 1005.32 762.42 1138.19 1.50 1.145 0.066 62 357.22 1005.74 773.55 1139.08 -1.50 1.146 0.066 63 354.72 1005.01 781.61 1139.73 1.50 1.150 0.069 64 357.22 1005.74 777.57 1139.41 1.50 1.151 0.069 65 354.72 1005.01 780.60 1139.65 1.50 1.151 0.070 66 358.47 1006.16 770.52 1138.84 -1.50 1.152 0.068 67 354.72 1005.01 779.59 1139.57 1.50 1.153 0.071 68 358.47 1006.16 769.51 1138.76 -1.50 1.153 0.069 69 354.72 1005.01 778.58 1139.49 1.50 1.155 0.072 70 358.47 1006.16 768.50 1138.68 -1.50 1.155 0.069 71 355.97 1005.32 785.65 1140.05 1.50 1.155 0.072 72 354.72 1005.01 777.57 1139.41 1.50 1.156 0.072 73 358.47 1006.16 767.49 1138.60 -1.50 1.156 0.070 74 358.47 1006.16 766.48 1138.52 -1.50 1.158 0.071 75 354.72 1005.01 791.71 1140.54 1.50 1.161 0.075 76 355.97 1005.32 761.41 1138.11 1.50 1.162 0.072 77 357.22 1005.74 773.53 1139.08 1.50 1.165 0.072 78 354.72 1005.01 776.56 1139.32 1.50 1.175 0.083 79 354.72 1005.01 775.55 1139.24 1.50 1.176 0.083 80 354.72 1005.01 774.54 1139.16 1.50 1.178 0.084 81 358.47 1006.16 765.47 1138.44 -1.50 1.182 0.084 82 359.72 1006.57 764.46 1138.36 -1.50 1.191 0.088 83 357.22 1005.74 772.54 1139.00 -1.50 1.192 0.092 84 359.72 1006.57 763.45 1138.28 -1.50 1.193 0.089 85 359.72 1006.57 762.44 1138.19 -1.50 1.194 0.089 86 359.72 1006.57 761.43 1138.11 -1.50 1.196 0.090 87 359.72 1006.57 760.42 1138.03 -1.50 1.197 0.091 88 355.97 1005.32 786.66 1140.13 1.50 1.199 0.096 89 359.72 1006.57 759.29 1137.76 -1.50 1.199 0.092 90 359.72 1006.57 769.51 1138.76 -1.50 1.201 0.094 91 354.72 1005.01 773.53 1139.08 1.50 1.201 0.097 92 354.72 1005.01 772.52 1139.00 1.50 1.203 0.098 93 359.72 1006.57 768.50 1138.68 -1.50 1.203 0.095 94 354.72 1005.01 792.72 1140.62 1.50 1.204 0.100 95 359.72 1006.57 767.49 1138.60 -1.50 1.205 0.095 96 359.72 1006.57 755.11 1136.37 -1.50 1.206 0.095 97 359.72 1006.57 766.48 1138.52 -1.50 1.206 0.096 98 359.72 1006.57 765.47 1138.44 -1.50 1.208 0.097 99 359.72 1006.57 773.55 1139.08 -1.50 1.217 0.103 Note: Y-Deflection values are failure surface mid-point vertical distances from the initial failure surface mid-point

Critical Failure Surface (4 points), adjusted for tension crack ------358.47 1006.16 568.24 937.26 661.34 938.64 790.72 1140.46

Non-Vertical Slice Geometry (4 slices) ------Slice ------Left Hand Side ------X-S ------Base ------Left-Hand-Side X-Top Y-Top X-Base Y-Base Area Angle Width Length Angle Length 1 358.47 1006.16 358.47 1006.16 12118.72 -18.2 209.77 220.79 0.0 0.00 2 533.06 1064.35 568.24 937.26 12388.83 0.9 93.10 93.11 -15.5 131.88 3 609.61 1089.87 661.34 938.64 15318.03 57.3 111.66 206.89 -18.9 159.83 4 760.00 1140.00 773.00 1112.82 451.22 57.3 17.72 32.83 -25.6 30.13 RHS 790.72 1142.46 790.72 1140.46 ------0.0 2.00 X-S Area: 40276.79 Path Length: 553.63

Non-Vertical Slice Properties (4 slices) ------Slice ---- Base ---- Left-Hand-Side Total-Extnl-Force - Water-Force - Effect-Normal-Stress Cohesion Phi Cohesion Phi Weight Vert Horiz Base Side Base Side 1 275.70 8.0 0.00 0.0 1329268.00 0.00 -241926.77 0.00 0.00 11008.81 0.00 2 543.99 5.8 15.19 32.4 1350567.75 0.00 -245803.33 0.00 4204.77 14511.76 8021.81 3 3.32 32.4 11.00 32.5 1684822.50 0.00 -306637.69 0.00 5027.82 3994.91 6265.26 4 0.00 33.0 0.00 33.0 49633.82 0.00 -9033.36 0.00 0.00 612.25 1000.32 RHS 0.00 0.0 ------0.00 0.00 X-S Weight: 4414292.00

———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————— CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243) Upper Shear Box: Concrete sand Agru 60-mil Microspike HDPE geomembrane #827103-13 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 201329LO/Roll #6291) with white geotextile side down/ Agru 8-250-8 geocomposite #528255-12/ Agru 60-mil Microspike HDPE geomembrane #827103-13 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 201329LO/Roll #6291) with white geotextile side down/ Lower Shear Box: Pink clay stone compacted to approximately 90% of max. standard Proctor dry unit weight at 60% to 62% moisture content

10000 20000 δ Shear Strength a R2 1A 1B 1C 1D Parameters (deg) (psf) 16000 Peak 20 100 0.996 8000 1E 1F 1G 1H LD 8 120 0.990

Peak 6000 12000 LD Linear (Peak) Linear (LD)

4000 8000 Shear Stress (psf) Shear Strength (psf)

2000 4000

0 0 0.0 0.8 1.6 2.4 3.2 0 4000 8000 12000 16000 20000 Displacement (in.) Normal stress (psf)

Test Shear Normal ShearSoaking Consolidation Cover Soil Pink Clay StoneUpper & Lower GCL Shear Strength Failure No. Box Size Stress Rate Stress Time Stress Time γd ωi ωf γd ωi ωf ωf ωf τP τLD Mode (in. x in.) (psf) (in./min) (psf) (hour) (psf) (hour) (pcf) (%) (%) (pcf) (%) (%) (%) (%) (psf) (psf) 1A 12 x 12 100 0.04 100 24 See - - - 49.9 62.5 - 135.7 118.6 63 42 (1) 1B 12 x 12 300 0.04 200 24 Page - - - 50.2 61.7 - 116.2 106.3 151 96 (1) 1C 12 x 12 500 0.04 200 24 B-6 - - - 50.4 60.9 - 95.8 101.3 234 173 (1) 1D 12 x 12 1000 0.04 200 24 - - - 50.1 62.0 - 86.2 93.5 383 293 (1) 1E 12 x 12 5000 0.04 200 24 - - - 50.5 60.6 - 60.2 59.4 2228 868 (2) 1F 12 x 12 10000 0.04 200 24 - - - 50.3 61.2 - 54.3 56.8 4063 1600 (2) 1G 12 x 12 14000 0.04 200 24 - - - 50.3 61.3 - 49.0 47.1 5110 1970 (2) 1H 12 x 12 18000 0.04 200 24 - - - 50.5 60.6 - 46.2 45.3 6727 2375 (2) NOTES: (1) Shear failure occurred at the interface between the geocomposite and white geotextile side of GCL. (2) Shear failure occurred at the interface between the pink clay and white geotextile side of GCL. DATE OF REPORT: 9/6/2013 FIGURE NO. 1 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-11.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243)

Upper Shear Box: Concrete sand Agru 60-mil Microspike HDPE geomembrane #827103-13 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 201329LO/Roll #6291) with white geotextile side down/ Agru 8-250-8 geocomposite #528255-12/ Agru 60-mil Microspike HDPE geomembrane #827103-13 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 201329LO/Roll #6291) with white geotextile side down/ Lower Shear Box: Pink clay stone compacted to approximately 90% of max. standard Proctor dry unit weight at 60% to 62% moisture content

Test Shear Test Soaking Consolidation

Normal Entire Test Specimen Consolidated for 12 hours under Each Load (psf)

No. Box Size Stress Stress Time Loading Step Numbers

(in. x in.) (psf) (psf) (hour) 12345678910

1A 12 x 12 100 100 24 100 1B 12 x 12 300 200 24 300 1C 12 x 12 500 200 24 500 1D 12 x 12 1000 200 24 1000 1E 12 x 12 5000 200 24 2000 4000 5000 1F 12 x 12 10000 200 24 2000 4000 6000 8000 10000 1G 12 x 12 14000 200 24 2000 4000 6000 8000 10000 12000 14000 1H 12 x 12 18000 200 24 2000 4000 6000 8000 10000 12000 14000 16000 18000

DATE OF REPORT: 9/6/2013 FIGURE NO. 2 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-11.ds.xls Project Name: Chem Waste SGI Testing Services, LLC Project No: SGI10020

4405 International Blvd., Suite B-117, Norcross, GA 30093 Client Sample ID: Pink Clay Ph: (770) 931 8222 Fax: (770) 931 8240 Lab Sample No: S17735

ASTM D698 COMPACTION MOISTURE-DENSITY RELATIONSHIP Standard - Method A

100

90

Gs=2.60

Gs=2.65 80 Gs=2.70

Gs=2.75 Dry Unit Weight (pcf) Weight Dry Unit 70 Curves of 100% Saturation for Specific Gravity Values

60

50 0 1020304050607080 Moisture Content (%)

Client SGI Compaction Data Maximum Dry Unit Weight and Optimum Moisture Content SampleSample Measured Corrected ω γ ω γ ω γ ID NO. i d om dmax om dmax ID.(%) (pcf) (%) (pcf) (%) (pcf) Subgrade Soil S17735 58.5 54.5 64.0 56.0 60.2 55.8 63.6 55.7 67.9 54.9 71.2 53.0 % Retained on #4 Sieve % Retained on #3/8" Sieve % Retained on 3/4" Sieve % Retained on 2.0" Sieve

S17735.Compaction.xls White NWGT of hydrated GCL “contaminated” by the pink clay

Figure 4. Shear failure at the interface between bottom surface (white NWGT) of the lower GCL and pink clay after the completion of test #1H at normal stress = 18000 psf

Figure 5. Close view of sheared surface of the pink clay after the completion of test #1H at normal stress = 18000 psf

A Georgia Limited Liability Company

11 October 2010 Mr. Dirk Wriedt, P.E. Environmental Information Logistics, LLC. 15556 Carries Lane South Beloit, IL 61080

Subject: Laboratory Test Results Transmittal Direct Shear Testing Chemical Waste Management of the Northwest - Cell 3

Dear Mr. Wriedt,

SGI Testing Services, LLC (SGI) is pleased to present the attached test results for the above-mentioned testing program. The note section below addresses sample preparation, sample disposal and a disclosure statement.

SGI appreciates the opportunity to provide laboratory testing services to Environmental Information Logistics, LLC. Should you have any questions regarding the attached document(s), or if you require additional information, please do not hesitate to contact the undersigned.

Sincerely,

Zehong Yuan, Ph.D., P.E. Laboratory Manager

Attachments

NOTES: (1) Unless otherwise noted in the test results the sample(s)/specimen(s) were prepared in accordance with the applicable test standards or generally accepted sampling procedures. (2) Contaminated/chemical samples and all related laboratory generated waste (i.e., test liquids, PPE, absorbents, etc.) will be returned to the client or designated representative(s), at the client’s cost, within 60 days following the completion of the testing program, unless special arrangements for proper disposal are made with SGI. (3) Materials that are not contaminated will be discarded after test specimens and archived specimens are obtained. Archived specimens will be discarded 30 days after the completion of the testing program, unless long-term storage arrangements are specifically made with SGI. (4) The reported results apply only to the materials and test conditions used in the laboratory testing program. The results do not necessarily apply to other materials or test conditions. The test results should not be used in engineering analysis unless the test conditions model the anticipated field conditions. The testing was performed in accordance with general engineering testing standards and requirements. The reported results are submitted for the exclusive use of the client to whom they are addressed.

SGI10020.REPORT.2010.01

Mail To: SGI Testing Services, LLC Facility Location P.O. Box 2427 4405 International Blvd., Suite B-117 Lilburn, GA 30048-2427 Norcross, GA 30093

Web Site: www.interactionspecialists.com Phone: 770.931.8222 Fax: 770.931.8240

ATTACHMENT A

TEST PHOTOS

Figure 1. Mixing bentonite with the Pink Claystone. Bentonite Added = 20% x dry weight of pink clay stone.

Figure 2. Geocomposite “print” on white nonwoven geotextile of GCL at the completion of a higher pressure test (Test Series 2).

Figure 3. Close view of geocomposite “print” on white nonwoven geotextile of GCL at the completion of a high pressure test (Test Series 2). The originally flat GCL surface (white geotextile) deformed to a “geonet-shaped” surface under a high normal stress, improving the GCL-geocomposite interface shear strength.

Figure 4. The surface of the Pink Claystone and shiny surface of Microspike after the completion of test #2H at normal stress = 18,000 psf

Figure 5. Close view of the shiny of Microspike after the completion of test #2H at normal stress = 18,000 psf

Figure 6. Bottom surface of the Pink Claystone and top (shiny) surface of Microspike after the completion of test #4C at normal stress = 1000 psf

Figure 7. Close view of Bottom surface of the Pink Claystone after the completion of test #4C at normal stress = 1000 psf

A soil moisture content specimen was taken from the center of the soil specimen after the completion of test #4C

Figure 8. Mosture sample location for test #4C at normal stress = 1000 psf

ATTACHMENT B

DIRECT SHEAR TEST RESULTS

CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 TEST SERIES #1 SCHEMATIC DIAGRAM OF MULTI-LAYER INTERFACE SHEAR TEST CROSS-SECTION (NOTE: NOT TO SCALE)

Protective cover soil

Agru 8-250-8 double-sided geocomposite

Agru 60-mil Microspike with long spike down

Concrete sand

Test No. Failure Mode

1A Sliding at the interface between protective cover soil and Agru 8-250-8 geocomposite 1B Sliding at the interface between protective cover soil and Agru 8-250-8 geocomposite 1C Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane 1D Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane 1E Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane 1F Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane 1G Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane 1H Sliding at the interface between the Agru 8-250-8 geocomposite dull side of Agru 60-mil Microspike HDPE geomembrane

DATE OF REPORT: 8/10/2010 FIGURE NO. B-1 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-01.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243)

Upper Shear Box: Protective cover soil nominally compacted at as-received moisture Agru 8-250-8 geocomposite #511696-09/ Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Lower Shear Box: Concrete sand

12000 20000 δ Shear Strength a R2 1A 1B 1C 1D Parameters (deg) (psf) 10000 1E 1F 1G 1H 16000 Peak 26 200 0.996 LD 12 120 0.994

8000 Peak 12000 LD Linear (Peak) 6000 Linear (LD) 8000

Shear Stress (psf) 4000 Shear Strength (psf)

4000 2000

0 0 0.0 0.8 1.6 2.4 3.2 0 4000 8000 12000 16000 20000 Displacement (in.) Normal stress (psf)

Test Shear Normal Shear Soaking Consolidation Cover Soil Subgrade Soil GCL Shear Strength Failure γ ω ω γ ω ω ω ω τ τ No. Box Size Stress Rate Stress Time Stress Time d i f d i f i f P LD Mode (in. x in.) (psf) (in./min) (psf) (hour) (psf) (hour) (pcf) (%) (%) (pcf) (%) (%) (%) (%) (psf) (psf) 1A 12 x 12 100 0.04 100 24 ------8051(1) 1B 12 x 12 300 0.04 300 24 ------169 151 (1) 1C 12 x 12 500 0.04 500 24 ------391 232 (2) 1D 12 x 12 1000 0.04 1000 24 ------716 360 (2) 1E 12 x 12 5000 0.04 5000 24 ------3058 1355 (2) 1F 12 x 12 10000 0.04 10000 24 ------5236 2380 (2) 1G 12 x 12 14000 0.04 14000 24 ------7063 2940 (2) 1H 12 x 12 18000 0.04 18000 24 ------8771 4110 (2) NOTES: (1) Shear failure occurred at the interface between the protective cover soil and geocomposite. (2) Shear failure occurred at the interface between the geocomposite and dull side of the geomembrane. DATE OF REPORT: 8/10/2010 FIGURE NO. B-2 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-01.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243)

Upper Shear Box: Protective cover soil nominally compacted at as-received moisture Agru 8-250-8 geocomposite #511696-09/ Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Lower Shear Box: Concrete sand

Test Shear Test Soaking Consolidation

Normal Entire Test Specimen Consolidated for 12 hours under Each Load (psf)

No. Box Size Stress Stress Time Loading Step Numbers

(in. x in.) (psf) (psf) (hour) 12345678910

1A 12 x 12 100 100 24

1B 12 x 12 300 300 24

1C 12 x 12 500 500 24

1D 12 x 12 1000 1000 24

1E 12 x 12 5000 5000 24

1F 12 x 12 10000 10000 24

1G 12 x 12 14000 14000 24

1H 12 x 12 18000 18000 24

DATE OF REPORT: 8/10/2010 FIGURE NO. B-3 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-01.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 TEST SERIES #2 SCHEMATIC DIAGRAM OF MULTI-LAYER INTERFACE SHEAR TEST CROSS-SECTION (NOTE: NOT TO SCALE)

Concrete sand

Agru Microspike with long spike down

Bentomat DN GCL with white geotextile down

Agru 8-250-8 double-sided geocomposite

Agru Microspike with long spike down

Pink claystone with 20% bentonite

DATE OF REPORT: 8/10/2010 FIGURE NO. B-4 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-02.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243) Upper Shear Box: Concrete sand Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 811CV/Roll #147) with white geotextile side down/ Agru 8-250-8 geocomposite #511696-09/ Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Lower Shear Box: Pink clay stone with 20% bentonite compacted to approximately 95% of max. standard Proctor dry unit weight at OMC

7000 20000 Shear Strength δ a 2 2A 2B 2C 2D R 6000 Parameters (deg) (psf) 2E 2F 2G 2H 16000 Peak 17 130 0.995 LD 9 115 0.993 5000 Peak 12000 LD 4000 Linear (Peak) Linear (LD)

3000 8000 Shear Stress (psf) 2000 Shear Strength (psf) 4000 1000

0 0 0.0 0.8 1.6 2.4 3.2 0 4000 8000 12000 16000 20000 Displacement (in.) Normal stress (psf)

Test Shear Normal Shear Soaking Consolidation Cover Soil Pink Clay Stone GCL Shear Strength Failure γ ω ω γ ω ω ω ω τ τ No. Box Size Stress Rate Stress Time Stress Time d i f d i f i f P LD Mode (in. x in.) (psf) (in./min) (psf) (hour) (psf) (hour) (pcf) (%) (%) (pcf) (%) (%) (%) (%) (psf) (psf) 2A 12 x 12 100 0.04 100 24 See - - - 48.3 77.7 - - 141.2 58 37 (1) 2B 12 x 12 300 0.04 200 24 Page - - - 48.7 76.2 - - 125.9 141 97 (1) 2C 12 x 12 500 0.04 200 24 B-6 - - - 48.4 77.4 - - 105.8 223 152 (1) 2D 12 x 12 1000 0.04 200 24 - - - 48.7 76.3 - - 83.4 411 311 (1) 2E 12 x 12 5000 0.04 200 24 - - - 48.8 75.9 - - 65.5 1821 1057 (2) 2F 12 x 12 10000 0.04 200 24 - - - 48.7 76.3 - - 59.6 3301 1715 (2) 2G 12 x 12 14000 0.04 200 24 - - - 48.7 76.2 - - 49.7 4331 2368 (2) 2H 12 x 12 18000 0.04 200 24 - - - 48.5 76.9 - - 46.7 5263 2804 (2) NOTES: (1) shear failure occurred at the interface between the geocomposite and white geotextile of the GCL. (2) shear failure occurred at the interface between the the long spike side of geomembrane and pink clay stone with 20% bentonite DATE OF REPORT: 8/10/2010 FIGURE NO. B-5 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-02.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243)

Upper Shear Box: Concrete sand Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Hydrated Bentomat DN GCL (Lot # 811CV/Roll #147) with white geotextile side down/ Agru 8-250-8 geocomposite #511696-09/ Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side down/ Lower Shear Box: Pink clay stone with 20% bentonite compacted to 95% of max. standard Proctor dry unit weight at OMC

Test Shear Test Soaking Consolidation

Normal Entire Test Specimen Consolidated for 12 hours under Each Load (psf)

No. Box Size Stress Stress Time Loading Step Numbers

(in. x in.) (psf) (psf) (hour) 12345678910

2A 12 x 12 100 100 24 100 2B 12 x 12 300 200 24 300 2C 12 x 12 500 200 24 500 2D 12 x 12 1000 200 24 1000 2E 12 x 12 5000 200 24 2000 4000 5000 2F 12 x 12 10000 200 24 2000 4000 6000 8000 10000 2G 12 x 12 14000 200 24 2000 4000 6000 8000 10000 12000 14000 2H 12 x 12 18000 200 24 2000 4000 6000 8000 10000 12000 14000 16000 18000

DATE OF REPORT: 8/10/2010 FIGURE NO. B-6 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-02.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 TEST SERIES #3 SCHEMATIC DIAGRAM OF INTERNAL SHEAR STRENGTH TEST CROSS-SECTION (NOTE: NOT TO SCALE)

Normal Load

Upper shear box Forced Shear Plane

Shear Load

6" thick compacted Pink Claystone with 20% bentonite

Lower shear box

DATE OF REPORT: 9/5/2010 FIGURE NO. B-7 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-03.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 DIRECT SHEAR TESTING (ASTM D 3080)

Internal shear strength of Pink clay stone with 20% bentonite compacted to approximately 95% of max. standard Proctor dry unit weight at OMC under soaked and consolidated conditions

10000 20000 Shear Strength φ c R2 3A 3B 3C 3D Parameters (deg) (psf) 8000 16000 Peak 20 410 0.991 3E 3F 3G 3H LD 11 165 0.998

Peak 6000 12000 LD Linear (Peak) Linear (LD)

4000 8000 Shear Stress (psf) Shear Strength (psf)

2000 4000

0 0 0.0 0.8 1.6 2.4 3.2 0 4000 8000 12000 16000 20000 Displacement (in.) Normal stress (psf)

Test Shear Normal Shear Soaking Consolidation Cover Soil Pink Clay Stone GCL Shear Strength Failure γ ω ω γ ω ω ω ω τ τ No. Box Size Stress Rate Stress Time Stress Time d i f d i f i f P LD Mode (in. x in.) (psf) (in./min) (psf) (hour) (psf) (hour) (pcf) (%) (%) (pcf) (%) (%) (%) (%) (psf) (psf) 3A 12 x 12 100 0.04 100 24 See - - - 48.5 77.1 - - - 235 118 (1) 3B 12 x 12 300 0.04 200 24 Page - - - 48.5 76.9 - - - 410 219 (1) 3C 12 x 12 500 0.04 200 24 B-9 - - - 48.4 77.2 - - - 520 278 (1) 3D 12 x 12 1000 0.04 200 24 - - - 48.8 75.9 - - - 729 411 (1) 3E 12 x 12 5000 0.04 200 24 - - - 48.5 76.8 - - - 2610 1255 (1) 3F 12 x 12 10000 0.04 200 24 - - - 48.4 77.2 - - - 4400 2030 (1) 3G 12 x 12 14000 0.04 200 24 - - - 48.6 76.5 - - - 5490 2970 (1) 3H 12 x 12 18000 0.04 200 24 - - - 48.8 75.7 - - - 6677 3777 (1)

NOTE: (1) Sliding (i.e., shear failure) was forced to occur along the shear plane between the upper and lower shear box. DATE OF REPORT: 9/5/2010 FIGURE NO. B-8 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-03.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 DIRECT SHEAR TESTING (ASTM D 3080)

Internal shear strength of Pink clay stone with 20% bentonite compacted to approximately 95% of max. standard Proctor dry unit weight at OMC under soaked and consolidated conditions

Test Shear Test Soaking Consolidation

Normal Each Test Specimen Consolidated for 12 hours under Each Load (psf)

No. Box Size Stress Stress Time Loading Step Numbers

(in. x in.) (psf) (psf) (hour) 12345678910

3A 12 x 12 100 100 24 100 3B 12 x 12 300 200 24 300 3C 12 x 12 500 200 24 500 3D 12 x 12 1000 200 24 1000 3E 12 x 12 5000 200 24 2000 4000 5000 3F 12 x 12 10000 200 24 2000 4000 6000 8000 10000 3G 12 x 12 14000 200 24 2000 4000 6000 8000 10000 12000 14000 3H 12 x 12 18000 200 24 2000 4000 6000 8000 10000 12000 14000 16000 18000

DATE OF REPORT: 9/5/2010 FIGURE NO. B-9 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-03.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 TEST SERIES #4 SCHEMATIC DIAGRAM OF INTERFACE SHEAR TEST CROSS-SECTION (NOTE: NOT TO SCALE)

Pink clay stone with 20% bentonite

Upper surface (shiny side) wetted by spraying approximately 25 g/sq ft tap water

Wetted Agru 60-mil Microspike with long spike up

Concrete sand

Test No. Failure Mode

4A Sliding at the interface between the long spike side of geomembrane and pink claystone with 20% bentonite 4B Sliding at the interface between the long spike side of geomembrane and pink claystone with 20% bentonite 4C Sliding at the interface between the long spike side of geomembrane and pink claystone with 20% bentonite

DATE OF REPORT: 9/17/2010 FIGURE NO. B-10 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-04.ds.xls CHEMICAL WASTE MANAGEMENT OF THE NORTHWEST - CELL 3 MULTI-LAYER INTERFACE DIRECT SHEAR TESTING (ASTM D 6243)

Upper Shear Box: Pink claystone with 20% bentonite compacted to approximately 95% of max. standard Proctor dry unit weight at OMC against Agru 60-mil Microspike HDPE geomembrane #226477-09 with long spike (shiny) side up (shiny side wetted by spraying approximately 25 g/ft2 tap water) Lower Shear Box: Concrete sand

700 1500 δ Shear Strength a R2 Parameters (deg) (psf) 600 4A 4B 4C 1200 Peak 24 80 0.996 LD 21 5 1.000 500 Peak 900 LD 400 Linear (Peak) Linear (LD)

300 600 Shear Stress (psf) 200 Shear Strength (psf) 300 100

0 0 0.0 0.8 1.6 2.4 3.2 0 300 600 900 1200 1500 Displacement (in.) Normal stress (psf)

Test Shear Normal Shear Soaking Consolidation Pink Claystone Lower Soil GCL Shear Strength Failure γ ω ω γ ω ω ω ω τ τ No. Box Size Stress Rate Stress Time Stress Time d i f d i f i f P LD Mode (in. x in.) (psf) (in./min) (psf) (hour) (psf) (hour) (pcf) (%) (%) (pcf) (%) (%) (%) (%) (psf) (psf) 4A 12 x 12 100 0.04 - - - - 48.6 76.5 81.0 - - - - - 116 43 (1) 4B 12 x 12 500 0.04 - - - - 48.8 75.9 82.3 - - - - - 317 198 (1) 4C 12 x 12 1000 0.04 - - - - 48.7 76.3 81.6 - - - - - 518 380 (1) 4D 12 x 12 4E 12 x 12 4F 12 x 12 4G 12 x 12 4H 12 x 12 NOTES: (1) shear failure occurred at the interface between the the long spike side of geomembrane and pink claystone with 20% bentonite. DATE OF REPORT: 9/17/2010 FIGURE NO. B-11 PROJECT NO. SGI10020 DOCUMENT NO. FILE NO.

S10020-04.ds.xls