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2016 Coal Combustion ResidualsAnnual InspectionJim Bridger Power PlantIndustrial LandfillPrepared forPacifiCorpNorth Temple Office1407 West North TempleSalt Lake City, Utah 84116October 20, 2016URS Corporation756 East Winchester, Suite 400Salt Lake City, Utah 84107

Contents1Findings . 12Description and History of Industrial Landfill . 23452.1General Overview . 22.2Location. 22.3Jim Bridger Industrial Landfill Description . 22.4Performance History . 22.5Construction History . 22.6Review of Operating Record Files . 22.6.1Design and Construction Information. 22.6.2Previous Periodic Structural Analyses. 32.6.3Results of Inspection by a Qualified Person. 32.6.4Results of Previous Annual Inspections . 3Field Inspection of Jim Bridger Landfill . 33.1General . 33.2Jim Bridger Industrial Landfill Geometry . 43.3Observed or Potential Structural Weaknesses . 43.4Observed Changes . 4Limitations and Consultant Qualifications . 44.1Limitations. 44.2Professional Engineer Qualifications . 4References . 5AppendicesAppendix APhotograph LogAppendix BAnnual Inspection Report Form2016 Jim Bridger Industrial Landfill Inspectioni

1FindingsThis annual inspection and report are being completed for the purpose of providing due diligence byPacifiCorp to ensure the safety of its coal combustion residual facilities. The inspection was performedaccording to the requirements for annual inspection 257.84 (for CCR landfills) of 40 CFR Parts 257 and261, Hazardous and Solid Waste Management System; Disposal of Coal Combustion Residuals fromElectric Utilities, Final Rule, dated April 17, 2015 [4].URS found no observations that would indicate imminent failure of the landfill slopes for the Jim BridgerPower Plant Industrial Landfill. There is no indication of movement of the embankment. Figure 1-1 is anaerial photograph of the landfill and retention ponds taken June 2015.Observations from the 2016 inspection include:1. Erosion along the south western bank of the Industrial Landfill’s northern retention pond hasbeen repaired and drainage flows diverted to concrete inlet structure. (Photo 3, Appendix A).2. New erosion rills and gully in cover over southwest slope of landfill (Photo 11, Appendix A). Theerosion is from significant rain earlier in the season. Erosion was repaired since this inspection.The photograph log in Appendix A also provides a basis for comparison for landfill conditions to comparewith future inspection observations.Figure 1-1. Jim Bridger Power Plant Industrial Landfill2016 Jim Bridger Industrial Landfill Inspection1

2 Description and History of Industrial Landfill2.1 General OverviewThe Jim Bridger Power Plant is operated by PacifiCorp.Fly ash and bottom ash produced by the plant are disposed of in the Industrial Landfill. These wastematerials are delivered to the landfill by haul truck.2.2 LocationThe Industrial Landfill is located approximately 1.8 miles north of the Jim Bridger Power Plant. The plantis located seven miles north of Point of Rocks, Wyoming [3]. The landfill is accessed by a haul road alongits southern boundary that is accessed from 9-Mile Road.2.3 Jim Bridger Industrial Landfill DescriptionThe Jim Bridger Power Plant consists of the power generating facility, numerous ponds, and theIndustrial Landfill. This study specifically addresses the CCR waste landfill identified as the Jim BridgerPower Plant Industrial Landfill. An aerial map the landfill is shown in Figure 1-1.The Industrial Landfill includes an area of approximately 200 acres1 It includes CCR deposited materialand an area for industrial waste of approximately 9 acres. There are two retention ponds that collectrunoff from the landfill. One is located on the north and the other on the east side of the landfill.2.4 Performance HistoryThere are no reported incidences of slope failure or movement of the landfill embankment in the recordfiles. In the summer of 2015, there were two significant flooding events that caused erosion of portionsof the northeast face. The eroded material was all contained in the retention basin on the north side ofthe landfill. Maintenance of erosion-prone slopes persisted in 2016 (see Photo 11, Appendix A).2.5 Construction HistoryThe plant has disposed of CCR at the Industrial Landfill since 1986 [3].2.6 Review of Operating Record FilesThe list of operating records to be reviewed during the annual inspection as contained in 40 CFR §257,Disposal of Coal Combustion Residuals for Electric Utilities is “CCR unit design and constructioninformation required by §§257.73(c)(1) and 257.74(c)(1), previous periodic structural stabilityassessments required under §§257.73(d) and 257.74(d), the results of inspections by a qualified person,and results of previous annual inspections”[4]. The following subsection describes the review ofoperating record files.2.6.1 Design and Construction InformationDesign and construction information for the Jim Bridger Industrial Landfill is found in the IndustrialLandfill Permit [5].1URS calculated area from aerial photography, Google Earth, April 30, 2014.2016 Jim Bridger Industrial Landfill Inspection2

2.6.2 Previous Periodic Structural AnalysesThere are no previous structural analyses of the Jim Bridger Industrial Landfill.2.6.3 Results of Inspection by a Qualified PersonJim Bridger Industrial Landfill is subject to periodic inspections by the Jim Bridger Power Plant staff. URSreviewed a sample of the inspection reports. These inspections are documented and retained byPacifiCorp. In the opinion of this report author, the interim inspections by the plant staff are adequateand appropriate for this CCR unit.2.6.4 Results of Previous Annual InspectionsThis is the first annual periodic inspection conducted under CCR rules [4] for the Jim Bridger IndustrialLandfill. URS performed the initial and most recent inspection in 2015 under the CCR rule; however,Wyoming Department of Environmental Quality conducted inspections [8] of the landfill in 2011, 2008,2003, and 1993 for compliance with the Wyoming Solid and Hazardous Waste Rules and Regulations.None of the observations from this or previous inspections have indicated imminent safety or slopeinstability concerns.This report and other pertinent reports and data are accessible at the following cr/ppw.htmlSection 5 of this report is a list of references reviewed for this report for the Jim Bridger IndustrialLandfill.3Field Inspection of Jim Bridger LandfillA field inspection was conducted on August 19, 2016, by URS staff, Rick J. Cox, P.E. and Bryan W. Franke,P.E. Personnel from the Jim Bridger Power Plant accompanied the URS team during the 2016 fieldinspection.A photograph log documenting features and their condition at the time of the inspection is presented inAppendix A. These photos are referenced in the report.The Annual Inspection Report Form is presented in Appendix B. This checklist should be considered anintegral part of the report and remain attached whenever the report is forwarded or otherwisereproduced.3.1 GeneralThe field inspection was performed by the URS inspection team by driving and walking various locationswithin the facility, which are in use or operation, including the north retention pond and south retentionpond. Intermittently, photos were taken of facility operations and features to provide a basis forcomparison with future inspections.Features and conditions were documented on the Annual Inspection Report Form (Appendix B) andwere photographed. The approximate locations of the photos are detailed in the inspection photographlog overview map located at the beginning of the Photograph Log, Appendix A. In addition to2016 Jim Bridger Industrial Landfill Inspection3

documenting current features, the photo log of existing conditions is intended on aiding futureinspections.3.2 Jim Bridger Industrial Landfill GeometryThere are no cross sections of the Industrial Landfill in the record file. However, based on the siteinspection the finished slopes are between 3 horizontal to 1 vertical (3:1) and 4:1.3.3 Observed or Potential Structural WeaknessesThere were no appearances of actual or potential structural weakness or existing conditions that aredisrupting, or have the potential to disrupt the operation and safety of the CCR unit.3.4 Observed ChangesSince the initial landfill inspection in 2015 performed under the CCR rules [4], the following changeswere identified:1. Erosion along the southwestern bank of the Industrial Landfill’s northern retention pond hasbeen repaired and drainage flows diverted to concrete inlet structure. Refer to Photo 3,Appendix A.2. New erosion rills and gully in cover over southwest slope of landfill. Refer to Photo 11, AppendixA. This item has been repaired since the inspection.4 Limitations and Consultant Qualifications4.1 LimitationsThis report presents observations, and conclusions drawn from a review of pertinent documentsreferenced in Section 5, and a field inspection of the Jim Bridger Industrial Landfill. The purpose of thereview and inspection has been to assess the safety or adequacy of the facilities against catastrophicfailure of the major constructed elements during normal operations or unusual or extreme events basedon visual inspection and available information. A secondary purpose is to identify any potentialdeficiencies related to the CCR rules [4].The conclusions and professional opinions presented herein were developed by the independentconsultant and are in accordance with generally accepted engineering principles and practices at thetime and location the services were provided. URS makes no other warranty, either expressed orimplied.4.2 Professional Engineer QualificationsThe professional engineer for this inspection is Rick J. Cox. He is licensed in the State of Wyoming(13825) as a civil engineer. He has over 34 years’ experience in civil/structural engineering and hasperformed inspections and safety evaluations on dams, canals and numerous other water containingstructures.2016 Jim Bridger Industrial Landfill Inspection4

5 References[1]URS, “2014 Coal Combustion Residuals Impoundment Inspection and Assessment – HunterPower Plant Ash Landfill”, January 6, 2015.[2]Wyoming Department of Environmental Quality, “Operating Permit, Jim Bridger Power PlantIndustrial Landfill”, April 26, 2013.[3]Water & Environmental Technologies, “2014 Annual Report, Ash Landfill Ground WaterMonitoring Program”, May 11, 2015.[4]40 CFS § 257 Disposal of Coal Combustion Residuals from Electric Utilities, April 17, 2015.[5]State of Wyoming, “Industrial Siting Permit, Jim Bridger Unit 4”, February 6, 1976.[6]GEI, "Final Coal Ash Impoundment - Specific Site Asssessment Report, PacifiCorp Energy, JimBridger Power Station”, September, 2009.[7]PacifiCorp Energy, “Plant Brochure: Jim Bridger Plant”, Point of Rocks, Wyoming, 2011.[8]Wyoming Department of Environmental Quality, “Compliance Evaluation Inspection Jim BridgerPower Plant and Industrial Landfill”. 2011, 2008,2003,1993.2016 Jim Bridger Industrial Landfill Inspection5

Appendix APhotograph Log2016 Jim Bridger Industrial Landfill Inspection

Inspection PhotographsPacifiCorp EnergyIndustrial Landfill – Jim Bridger Power PlantAugust 19, 2016Page No. A-1

Photograph No. 1 View of signage with facility name and accepted wastes.Photograph No. 2 View of active disposal area for ash delivered from plant.Inspection PhotographsPacifiCorp EnergyIndustrial Landfill – Jim Bridger Power PlantAugust 19, 2016Page No. A-2

Photograph No. 3 View of the industrial landfill’s northern retention pond.Photograph No. 4 View of cover placed over ash waste.Inspection PhotographsPacifiCorp EnergyIndustrial Landfill – Jim Bridger Power PlantAugust 19, 2016Page No. A-3