SEGMENT 1 PHASE 2 WORK CAG - SEPTEMBER 16, 2013

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Segment 1 - Selected Remedies

• SMA 1 – Cap

• SMA 2, 3 &6 – (DNAPL) removal and treatment, install physical containment (cap, sheet pile)

• SMA 4 & 5 – Cap

SMA 2 DNAPL Removal & Containment

SMA 3 DNAPL Removal & Containment

SMA 6 DNAPL Removal & Containment

2013 Segment 1 Activities

SMA 1 - Cap

2013 Segment 1 Phase II Activities

DNAPL Recovery

• DNAPL recovery reconvened May

• Installed approximately 156 wells

• Installed a shore base well in SMA 2 July

• Successfully reducing the amount of DNAPL to allow for containment installations.

• Removed 5,448 liters of DNAPL in 2013, total of about 15,000 liters.

River Access System & Sonic Rig

2013 Segment 1 Phase II Activities Completed

Containment Systems

– SMA 2 July

– SMA 6U August

– SMA 3 Sept.

2013 Segment 1 Phase II Activities

Remaining activities:

• SMA 6L Containment Early October

• SMA 1 being evaluated to understand impacts from a potential NRD project with the Dow Dam

SMA Containment System

DNAPL recovery wells

SMA boundary

Existing rip/rap along edge of river

Removal of Rip Rap

Removal of Recovery Wells

Installation of Crane Mats

Installation of Sheet Pile

Installation of GCL Cap (geosynthetic clay layer)

Installation of Armor Stone

Relocate Crane Mats

Installation of GCL Cap

Installation of Armor Stone

Relocate Crane Mats

Installation of GCL Cap

Installation of Armor Stone

Remove Crane Mats

Installation of GCL Cap

Installation of Armor Stone

Replace Rip Rap

Rip-Rap Removal

Temporary ramp construction

Sheet Pile Installation

Sheet Pile Installation

Sheet Pile Installation

08-09-13 Cutting Sheet Pile – Diver Assisted

Connecting to RGIS Sheet Pile

08-13-13

SMA-6 (U)

Relocating Crane Mats

SMA 2 – Moving crane mat

Installing geosynthetic clay liner (GCL) for low permeability cap

Installing GCL

08-11-13 Stone Bags on Barge

Installing armor layer of cap

SMA 2 – Cap Abutting RGIS

Aqua-block installation

Sand Installation

Geotextile Installation

End