NIPSCO MCGS PRIMARY 2 CCR CLOSURE PLAN

Transcription

1 NIPSCO MCGS PRIMARY 2 CCR CLOSURE PLAN CLOSURE PLAN Submitted To: Northern Indiana Public Service Company Michigan City Generating Station 101 Wabash Street Michigan City, Indiana Submitted By: Golder Associates Inc. 670 North Commercial Street, Suite 103 Manchester, NH USA A world of capabilities delivered locally December 2015 Project No.: Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation

2 December 2015 i Project No.: Table of Contents 1.0 BACKGROUND Impoundment Description Closure Narrative Notifications HISTORICAL AMOUNT AND EXTENT OF CCR Maximum Inventory of CCR Extent of CCR CLOSURE PERFORMANCE STANDARD Closure Plan and Approach Drainage and Stabilization of CCR Final Cover System Liner Subgrade Geomembrane Liner Geocomposite Drainage Layer Vegetative Support/Protection Layer Stormwater Management CLOSURE PROCESS Protection of Impoundment Berms and Utilities Dewatering, Stabilization, and Placement of CCR Subgrade Installation of Final Cover System Stormwater Management Field Oversight and CQA Testing POST-CLOSURE CLOSURE SCHEDULE CLOSURE CERTIFICATION List of Figures Figure 1 Site Location Map Figure 2 Primary 2 Existing Conditions Figure 3 Primary 2 Final Closure Grading Plan Figure 4 Primary 2 Cross Sections Figure 5 Closure Schedule List of Exhibits Exhibit A Statement of Certification

3 December Project No.: BACKGROUND The Northern Indiana Public Service Company (NIPSCO) Michigan City Generating Station (MCGS or Site) is an operating 469 MW capacity coal-fired electric generating plant that began production in Electricity is produced by a single high-pressure boiler and steam turbine-powered generator (referred to as Unit 12). MCGS, located at 101 Wabash Street in Michigan City, LaPorte County, Indiana, occupies 131 acres in a mixed industrial, commercial, and residential area along the southern shoreline of Lake Michigan (refer to Figure 1, Site Location Map). Prior to October 19, 2015, NIPSCO discontinued the addition of wastes regulated under the CCR Final Rule to Primary Settling Basin #2 (Primary 2). NIPSCO intends to close Primary 2 in-place and in conformance with the requirements of 40 Code of Federal Regulations (CFR), Part (b). This document represents the closure plan, including necessary engineering certification (refer to Exhibit A), for the impoundment consistent with the requirements of 40 CFR, Part Impoundment Description As shown on Figures 1, 2, and 3, Primary 2 is a roughly 3-acre structure, located in the southwestern portion of the Site. Primary 2 was constructed in the early 1970 s and is approximately 435 feet long, ranging from approximately 230 to 290 feet wide, with a maximum theoretical capacity of approximately 70,000 cubic yards (cu yd). Historical figures indicate the floor and perimeter embankments of Primary 2 were constructed from compacted sand fill and the floor and sideslopes were lined with a one foot thick layer of crusher run blast furnace slag. The exterior sideslope of the western embankment was lined with eight inch riprap. The embankment that forms Primary 2 is approximately 14 feet high on the outside slope and approximately 20 feet high on the inside slope. Both the interior and exterior slopes are 2.5H:1V. The crest of the embankment is approximately 15 to 21 feet wide and is at approximately El The top of the crusher run blast furnace slag lining the floor of the impoundment is at approximately El. 591 and the surrounding ground outside the embankments varies from approximately El. 596 to El When active, Primary 2 received fly ash, economizer ash, recirculated water from the ash sluice system, boiler blow down, and wastewater from the boiler drains sluiced directly from the generating station. Primary 2 was formerly operated on an alternating basis with Primary Settling Basin #1 (Primary 1), now out of service. Primary 2 discharged water, which remained after the majority of the solids settled out of the aqueous solution, to Secondary 2, also out of service. Periodically during its operating life, as Primary 2 approached or reached capacity, CCR discharge to it was halted and redirected to former Primary 1. After the contents of Primary 2 were allowed to dry, the dewatered material was excavated and

4 December Project No.: transported off-site for disposal. Currently Primary 2 contains both CCR and liquids. Water levels within Primary 2 were and continue to be manually controlled by MCGS operations personnel. 1.2 Closure Narrative Pursuant to the requirements of 40 CFR, Part (c) (1), development of the Primary 2 closure plan, including this closure narrative, was completed by December 17, Closure activities at the inactive surface impoundment are anticipated to begin in the spring of 2017, in accordance with all requisite notifications and consistent with the closure schedule discussed in Section 6.0 of the closure plan. Closure of Primary 2 will be by leaving CCR in-place and constructing a CCR Final Rule compliant cover system. Key steps of the closure process may include, but are not necessarily limited to, collection and interpretation of geotechnical data as necessary to support design activities, development of conceptual and final designs, disabling operational infrastructure, dewatering and grading of impoundment contents, installation of stormwater diversion and outlet structures, preparation of a suitable subgrade for the final cover system, construction of final cover system and additional drainage as necessary, seeding, mulching, and maintenance and repair until the vegetative layer of the cover system is established. Subsequent to completion of all construction and verification activities, notification and engineering certification of closure will be performed. 1.3 Notifications The closure process requires a series of notifications to be completed prior to, during, and subsequent to closure activities. Pursuant to 40 CFR, Part (c), by no later than December 17, 2015, NIPSCO will prepare and place in the MCGS facility s operating record a notification of intent to initiate closure of the inactive Primary 2 surface impoundment. This notification will include a narrative discussion of the closure approach, a closure schedule, and required engineering certifications. Periodic progress reports as required pursuant to 40 CFR, Part (c) (1) (i) and (ii) will be completed and placed in the facility s operating record as will a notification of completion of closure and the engineering certification pursuant to 40 CFR, Part (c) (3). 2.0 HISTORICAL AMOUNT AND EXTENT OF CCR Pursuant to 40 CFR, Part (b) (iv and v), multiple resources were reviewed to estimate the maximum inventory of CCR ever on-site over the active life of the unit and to estimate the largest area of Primary 2 requiring a final cover. These resources included: historical construction drawings, an existing conditions topographic survey drawing, recent field investigation findings, historical aerial photographs, and discussions with MCGS facility personnel.

5 December Project No.: Maximum Inventory of CCR According to MCGS facility personnel, between the time of construction of Primary 2 in the early 1970 s and approximately 1990, MCGS operated using a wet fly ash collection and management system. MCGS personnel estimate that during this timeframe Primary 2 was dredged of accumulated CCR at a likely frequency of once every two to three years. Since about 1990, the plant has operated a dry fly ash collection system, so CCR accumulation and the frequency of required dredging has been greatly reduced. Over the life of Primary 2 there have been no known or documented releases of CCR and the CCR has been maintained at or below the maximum operating capacity of two feet below the top of the embankment. During the summer of 2015, Golder performed a geophysical survey within Primary 2 to assess the base (bottom) elevation of the impoundment and thickness of CCR materials. The geophysical survey indicates that the base of the impoundment varied from approximately El. 586 to El. 595 with an average base elevation of 591. The top of CCR materials was estimated to vary between El. 593 and El This results in an estimated CCR material thickness of two to nine feet, with an estimated volume of 19,000 cu yd. Marbach, Brady, & Weaver, Inc. performed a topographic survey of Primary 2 in July The existing conditions survey drawing indicates that the water level in the pond at that time was at approximately El. 607, two feet below the crest of the berm (i.e., maximum operating capacity of Primary 2). Therefore at the time of the survey and based on the data collected from the geophysical survey, there was approximately 8,000,000 gallons of free liquid (above crusher run blast furnace slag and CCR sediments) within Primary Extent of CCR Based on review of historical drawings, photographs, and discussions with MCGS personnel, two vertical feet below the inside crest of the perimeter embankment berm, as shown on the existing conditions drawing (Figures 2 and 3), represents the largest boundary of the CCR unit, with the exception of the southeast corner of the pond. During operation, it appears that NIPSCO pushed materials into the southeastern corner of the pond creating the flat plateau area that is shown on the existing conditions drawings (Figure 2). Since the current topography along the southeastern corner appears to no longer represent the largest limit of CCR, the limit of the final cover will be extended in this corner to include the estimated original limit of the impoundment in this area. This estimated original limit of CCR, which represents the largest boundary of the CCR unit ever requiring a final cover, pursuant to 40 CFR, Part (b) (1) (v) is also shown on Figure 3 and is estimated to be approximately 3.0 acres. 3.0 CLOSURE PERFORMANCE STANDARD Consistent with the requirements of 40 CFR, Part (b) (1-4), NIPSCO will close Primary 2 by leaving CCR in-place. Closure in-place will be accomplished by installation of a final cover system that

6 December Project No.: will minimize or eliminate infiltration into the waste, minimize or eliminate releases of CCR into the environment, promote positive drainage away from the CCR unit thus impeding future collection of water or sediments over the footprint of the impoundment, provide a stable cover that minimizes the need for post closure maintenance, and can be constructed in a timely manner using sound engineering practices. NIPSCO intends to construct the closure of Primary 2 following an alternative final cover system design as allowed under 40 CFR, Part (d) (3) (ii). 3.1 Closure Plan and Approach Following dewatering, CCR sediments will be dried and stabilized within the existing confines of Primary 2. As shown on Figure 3, NIPSCO intends to construct an approximately 3.7 acre final cover system encompassing the limits of Primary 2 with a uniform cross-slope graded to drain from west to east. Under the proposed final cover design, all stormwater drainage will shed to the east off the Primary 2 final cover and onto the interior facility access road system which in this area currently discharges to the Final Pond. Grading along the western perimeter is planned to match the existing top of embankment elevations and slope downward to the east with a uniform two percent cross-slope extending to the existing grades near the base of the outside of the eastern embankment. Grading along the southern and northern embankments is also planned to match the existing top of embankment elevations and then slope downward with a uniform slope of twenty percent (5H:1V) until intersecting the cross-sloping grades. To minimize the encroachment of final cover activities on the existing Transmission Line Tower T8463, located adjacent to the northeastern corner of the pond, the grading in the northeastern corner will tie in two feet below the existing top of embankment. This corresponds to the maximum operating capacity elevation of the pond. In order to tie into surrounding grades along the eastern limit of the final cover, the majority of the eastern embankment will need to be removed. NIPSCO intends to excavate and reuse the embankment material as additive material for drying and stabilization of the CCR sediments. If necessary, additional backfill will be placed above the stabilized CCR/backfill materials to achieve the proposed CCR subgrade elevations. Following CCR subgrade preparation, the final cover liner system will be installed and vegetated. 3.2 Drainage and Stabilization of CCR Prior to the start of closure construction earthwork, free liquid will be removed from Primary 2. Dewatering liquid will be conveyed and discharged into the Final Pond where it will be held and discharged under the current NPDES permit. Following removal of the free liquid, the CCR materials will be pushed into stockpiles or windrows for drying and subsequent blending. The excavated eastern embankment soils will be blended with the CCR materials to achieve a stable composite backfill material. NIPSCO also intends to use facility-generated

7 December Project No.: boiler slag as additional backfill material consistent with the beneficial use provisions of the CCR Final Rule. Once the composite backfill material is processed and stability is achieved, the material will be placed and compacted in lifts to the approved final cover CCR subgrade elevations. All drying, blending, and stabilization operations will be performed within the existing impoundment limits. 3.3 Final Cover System The proposed final cover section meets the engineering property requirements outlined in the alternative final cover system design as allowed under 40 CFR, Part (d) (3) (ii) including a permeability less than or equal to 1x10-5 cm/sec, an equivalent reduction in infiltration as provided by a minimum of 18 inches of earthen material, and an equivalent erosion layer that provides the same protection from wind or water erosion as provided by a minimum of 6 inches of earthen material capable of sustaining native plant growth. NIPSCO proposes the following alternative final cover section for the in-place closure of Primary 2. Refer to Figure 4 for the Final Closure Typical Section. Primary 2 Final Cover System (top to bottom) 18 min. Vegetative Support/Protection Layer Geocomposite Drainage Layer Geomembrane Liner 6 Liner Subgrade A detailed description of each layer, described in the order of installation (bottom to top) is included below Liner Subgrade The proposed final cover section includes installation of a minimum six-inch thick liner subgrade layer above the CCR subgrade (reference Section 3.2) surface and below the geomembrane liner. The purpose of this layer is to provide protection for the geomembrane liner material from any oversized or angular particles that may be present in the CCR subgrade material backfill. The liner subgrade material shall be a uniform sand, or equivalent, with maximum particle size of one-inch Geomembrane Liner A geomembrane liner will be placed above the liner subgrade material. Geomembrane liners are essentially impermeable and will act as a low permeability layer and infiltration barrier for the final cover system. The liner will be terminated and secured on all sides in a buried anchor trench which will further inhibit any potential releases of CCR material from beneath the cover system. The geomembrane liner

8 December Project No.: material shall be a PVC, LLDPE, HDPE, or equivalent geomembrane with sufficient physical properties to meet the design requirements Geocomposite Drainage Layer A geocomposite drainage layer will be placed above the geomembrane liner. The geocomposite drainage layer will act as an infiltration drainage pathway and also provide protection to the geomembrane liner during installation of overlying soil material. The geocomposite drainage layer shall be a composite heat-bonded geotextile fabric and synthetic geonet, or equivalent. The geocomposite shall be specified with sufficient physical properties to support the design requirements, to perform in conjunction with the overlying soils to provide drainage filtration to keep silt and soil particles from clogging the flow channels, and collect and convey infiltration off the geomembrane liner Vegetative Support/Protection Layer A minimum 18-inch thick vegetative support/protection layer is proposed to be placed above the geocomposite drainage layer. The vegetative support/protection layer will serve three purposes: to protect the geosynthetic layers from equipment or vehicular loading, UV-degradation, and other unforeseen damages; to provide a suitable, nutrient rich material that is capable of supporting native plant growth that will in turn minimize erosion of the final cover materials from wind and rain; and to limit stormwater infiltration into the final cover system. The vegetative support/protection material shall be an earthen material that is enriched in organic matter and has textural and structural characteristics favorable to plant growth. The surface of the vegetative support layer will be vegetated with an approved seed and mulch mixture to control erosion, promote germination of seeds, and increase the moisture retention of the soil until permanent vegetation is established. 3.4 Stormwater Management Stormwater is currently managed at MCGS under an active NPDES Permit (No. IN ). The stormwater that currently falls within the footprint of Primary 2 is managed within the impoundment. Stormwater is collected through an outfall and conveyed by pipe away from Primary 2 and then discharged into the Final Pond. Discharge from the Final Pond discharges through Internal Outfall 301, and eventually discharges through the main facility outfall (Outfall 001) directly into Lake Michigan. Prior to Primary 2 closure construction activities, the outfall piping connection between Primary 2 and the Final Pond will be removed. Following Primary 2 final cover construction, the stormwater that falls within the footprint of Primary 2 will shed to the east by sheet flow into the interior haul road watershed area, adjacent to the coal pile. This area currently drains into the Final Pond and ultimately Lake Michigan as detailed above.

9 December Project No.: CLOSURE PROCESS 4.1 Protection of Impoundment Berms and Utilities As discussed above, Primary 2 is formed by embankment berms on all sides. The proposed final cover grading requires tying the new final cover system into the top of the embankment along the northern, western, and southern limit of the final cover and two feet below the top of the embankment in the northeastern corner. An approximately two-foot deep anchor trench will be excavated into the embankment along these three sides to secure the synthetic final cover materials. Historical construction drawings indicate that there are no existing utilities in this area along the top of the embankments. The proposed final cover grading plan requires removal of the eastern perimeter embankment to allow for stormwater drainage across the cover. Historical drawings indicate that there are at least four buried pipes ranging in diameters from 6 inches to 11 feet running beneath and parallel to the eastern perimeter embankment. Historical drawings and discussions with facility personnel suggest that the existing pipes are buried between 8 and 10 feet below the surrounding grades. Since the proposed final cover grading plan only removes the eastern embankment and does not cut into the surrounding grades, the proposed final cover activities should not pose potential damage to or compromise the integrity of the existing utilities. In addition, two transmission tower foundations are located adjacent to the northeast and southeastern corners of the final cover. Care should be taken when working around these structures and underneath the overhead electric lines. The contractor will be responsible to locate and protect all utilities prior to the start of construction. 4.2 Dewatering, Stabilization, and Placement of CCR Subgrade As discussed above, MCGS anticipates up to approximately 8,000,000 gallons of free liquid will need to be removed from Primary 2 prior to the start of construction. Dewatering will be achieved using trailer mounted pumps located at low points across the impoundment floor. Dewatering liquid will be discharged into the Final Pond where it will be held and discharged under the current NPDES permit. Following removal of the free liquid, the CCR materials will be pushed into stockpiles or windrows for drying and mixing. The stockpiles will be managed and worked such that liquid expelled from the solids during the stockpile turning/drying process can be directed to pump intakes for continued dewatering. Concurrently, the eastern embankment will be excavated to achieve final cover subgrade elevations. The excavated embankment soils will be mixed with the CCR materials to achieve a composite backfill for CCR subgrade material. It is anticipated that the CCR material will require a blending ratio between a 1:1 and 1.5:1 backfill to CCR to achieve a stable composite backfill material capable of structural support of the final cover system. NIPSCO plans to perform a bench scale testing to confirm this theoretical blending ratio prior to the completion of final design.

10 December Project No.: To achieve the proposed final cover subgrade elevations, approximately 36,000 cu yd of backfill material will be required in addition to the CCR sediments currently in the impoundment. Approximately 5,500 cu yd of excavated embankment sand will be available for use as blending backfill. Therefore additional imported backfill material, potentially including Site boiler slag as mentioned above, will be required to complete final cover construction. Depending on the observed physical characteristics of the CCR and embankment fill mixture, the additional backfill may be mixed with the CCR materials prior to placement or placed directly as backfill. The backfill material will be mixed and dried until it reaches a moisture content suitable for effective placement and compaction. All CCR subgrade backfill materials will be placed at or near the optimum moisture content and compacted in lifts to the approved final cover CCR subgrade elevations. Areas that do not achieve sufficient compaction (i.e., pumping and weaving) due to excessive water content will be removed and replaced with drier and/or coarser grained material (e.g., 3/4 inch crushed stone). All drying, mixing, and stabilization processes will be performed within the limits of the final cover. Therefore, the construction will need to be staged so that mixing operations can be performed at one end of the impoundment while placement and compaction is occurring at the other end of the impoundment. 4.3 Installation of Final Cover System Following completion and acceptance of the CCR subgrade installation, the layers of the proposed alternative final cover sections will be install as follows. 6 Liner Subgrade: The liner subgrade soil shall be placed in a single minimum six-inch thick layer. Following installation, the layer thickness shall be verified by completing a series of hand dug test pits across the footprint, or by applying an approved equivalent method. Geomembrane Liner: The liner shall be installed in panels oriented in the direction of flow. Panel seams will be welded in-situ and tested for defects. The liner will be terminated and secured in an approximately two-foot deep anchor trench. Geocomposite Drainage Layer: The geocomposite will be installed in panels oriented in the direction of flow, or as recommended by the manufacturer for maximum transmissivity. The geonet core of adjacent sheets will be zip-tied together and the top seams of the geotextile fabric will be sewn together to prevent intrusion of the materials placed above. The geocomposite will be terminated and secured within the anchor trench on the uphill side (west) and sideslopes (north and south). The downhill (east) edge will daylight across the top of the anchor trench to allow for discharge of infiltrated stormwater. Vegetative Support/Protection Layer: The vegetative support layer shall be placed in a single minimum eighteen-inch thick layer. The final surface of the vegetative support soil will be tracked perpendicular to

11 December Project No.: the direction of flow for added erosion protection and to assist in the establishment of vegetation. Following installation, the layer thickness shall be verified by completing a series of hand dug test pits across the footprint, or approved equivalent method. In addition, seeding and mulching will be applied to the surface to prevent erosion until vegetation can be established. 4.4 Stormwater Management The conceptual final cover design presented in this closure plan assumes that all Primary 2 stormwater will be managed through sheet flow across the cover. If, during final design, it is determined that stormwater control structures (i.e., tack-on swales) are required to better manage the stormwater flows, they shall be incorporated into the final design, as appropriate. 4.5 Field Oversight and CQA Testing NIPSCO intends to have full time field oversight and Construction Quality Assurance (CQA) testing performed during subgrade earthwork operations and construction of the final cover system. It is anticipated that field oversight and CQA testing duties will include: Preparation of daily field reports, which will include installed material quantity estimates; Attendance at construction progress meetings; Securing geosynthetics product information from the manufacturer s QA testing; Inventory of geosynthetic materials as they arrive on-site; Collecting samples, coordinating testing and documenting results of conformance testing for geosynthetics and soils; Preparing photographic documentation of construction; Assisting contractor with coordinating and reviewing survey for as-built record documents; and Field inspection and documentation of: Results of startup procedure for seam welders; Geomembrane non-destructive seam testing and trial seams; Panel layout and location of repairs; Collection of samples for testing on destructive samples; Seaming of geocomposite; Collection of samples for testing on soil samples; and Soil placement criteria A CQA plan detailing CQA personnel responsibilities, testing frequencies, and material/design requirements during construction will be prepared and submitted with the final design.

12 December Project No.: POST-CLOSURE NIPSCO is closing inactive surface impoundment Primary 2 through closure by leaving CCR in-place. Closure will be completed no later than April 17, 2018, pursuant to 40 CFR, Part (b). As outlined in 40 CFR, Part (a) (3), the owner/operator of an inactive CCR surface impoundment that elects to close a CCR impoundment pursuant to the requirements under 40 CFR, Part (b) is not subject to post-closure care criteria under the Federal regulations. 6.0 CLOSURE SCHEDULE NIPSCO intends to complete closure of Primary 2 within one construction season, between May 2017 and September The currently proposed schedule plans for closure to be completed approximately seven months prior to the April 17, 2018 closure deadline as specified by 40 CFR (b). This schedule is subject to change and dependent upon availability of imported construction materials, available labor and equipment at the time of construction, favorable weather conditions, and minimal unanticipated delays. Should delays arise, there is time in the schedule to allow for time extensions and completion of construction and closure certification by the final regulatory deadline. The table below outlines the major milestones required for closure. Refer to the Figure 5 for a more detailed construction schedule. Construction Milestone Anticipated Date Begin Dewatering May 2017 Begin Subgrade CCR Earthwork June 2017 Begin Geomembrane Liner Placement August 2017 Complete Vegetative Support/Protection Layer Placement September CLOSURE CERTIFICATION As demonstrated throughout this plan, NIPSCO intends to close inactive Primary 2 through closure by leaving CCR in place no later than April 17, 2018, and has developed the closure plan in conformance with the requirements of 40 CFR, Part In compliance with 40 CFR, Part (b) (4) and (6), a Statement of Certification is appended to this plan and located in Exhibit A. Pursuant to 40 CFR, Part (c) (3), within 60 days of completion, a Notification of Completion of Closure including the appropriate engineering certification will be prepared and placed in the facility s operating record.

13 FIGURES

14 ³ SITE Indiana ³ LEGEND Approximate Property Line CCR Unit to be Closed Final Pond L A K E M I C H I G A N Bottom Ash Pond Boiler Slag Former Secondary 2 MICHIGAN CITY Primary 2 Path: V:\001 GIS Projects\2015\ NIPSCO\ST_D Michigan City Engineering\ D001.mxd Modified By: CSCHAEFER Former Primary 1 Former Secondary 1 REFERENCES Elevations are in North American Vertical Datum 88 Orthophoto image source: Indiana University, Indiana Spatial Data Portal (gis.iu.edu). "The IndianaMap", an initiative of the Indiana Geographic Information Council, Inc. (IGIC), Indiana's statewide GIS coordination council Indiana western counties, 6 in. resolution: Dated 4/4/2013 REV. DATE DES REVISION DESCRIPTION GIS CHK RVW PROJECT TITLE NORTHERN INDIANA PUBLIC SERVICE COMPANY MICHIGAN CITY GENERATING STATION MICHIGAN CITY, INDIANA DESIGN GIS CHECK Manchester, New Hampshire REVIEW PROJECT No RAW CDS MEM RAW Feet SITE LOCATION MAP 12/15/2015 FILE No D001 11/30/2015 SCALE: AS SHOWN REV. 0 12/15/ /15/2015 FIGURE 1

15 FINAL POND APPROXIMATE LIMIT OF PRIMARY 2 FORMER SECONDARY 1 PRIMARY 2 APPROXIMATE LIMIT OF PRIMARY 2 FORMER SECONDARY 2 Path: \\manchester\cadd\drawings\2015\nipsco\temporary MCGS Storage\Liner Revision 1\ File Name: Revised Approx Limit of Primary 2.dwg LEGEND EXISTING CONTOUR EDGE OF WATER (07/08/2015) APPROXIMATE LIMIT OF PRIMARY 2 REFERENCES 0 1. "EMBANKMENT & SOIL BORING MONITORING WELL SURVEY NIPSCO MICHIGAN CITY GENERATING STATION PT. NW 1/4, SEC. 29, T38N, R4W AND PT. NE 1/4, SEC. 30, T38N, R4W MICHIGAN TOWNSHIP, LAPORTE COUNTY 1'' = 60' INDIANA." BY MARBACH, BRADY & WEAVER, INC. DATED 7/8/ HORIZONTAL AND VERTICAL DATA FOR THIS SURVEY ARE BASED ON A SOLUTION DERIVED FROM GLOBAL POSITIONING SYSTEM (GPS) OBSERVATIONS PROCESSED A CONTINUOUSLY OPERATING REFERENCE STATION. THE COORDINATE SYSTEM IS US STATE PLANE 1983, NAD 1983 (CONUS), INDIANA WEST ZONE. GROUND ELEVATIONS ARE BASED UPON SAID INDOT SOLUTION AND ARE ON THE 1988 NORTH AMERICAN VERTICAL DATUM (NAD88). THIS ORTHOMETRIC ELEVATION WAS DERIVED UTILIZING THE MOST RECENT GEOID MODEL (GEOID12A). IT IS 3. REFERENCE STATION USED: INLP LAPORTE CORS ARP CLIENT NORTHERN INDIANA PUBLIC SERVICE COMPANY CONSULTANT YYYY-MM-DD DESIGNED PREPARED REVIEWED APPROVED APPROXIMATE LOCATION OF T8463 TRANSMISSION TOWER MCM RWC MCM RAW PROJECT NORTHERN INDIANA PUBLIC SERVICE COMPANY MICHIGAN CITY GENERATING STATION MICHIGAN CITY, INDIANA TITLE PRIMARY 2 EXISTING CONDITIONS PROJECT NO SUBTITLE A EDGE OF WATER REV FEET FIGURE 2 IF THIS MEASUREMENT DOES NOT MATCH WHAT IS SHOWN, THE SHEET SIZE HAS BEEN MODIFIED FROM: ANSI B 0 1 in

16 APPROXIMATE EDGE OF WATER B FORMER SECONDARY 1 B' Path: \\manchester\cadd\drawings\2015\nipsco\temporary MCGS Storage\Road Grade Revision\ File Name: Primary 2 Road Revision 2.dwg LEGEND A EXISTING CONTOUR PROPOSED CONTOUR (TOP OF VEGETATIVE SUPPORT/PROTECTION LAYER) LIMIT OF PRIMARY 2 CROSS SECTION LINE EDGE OF WATER LIMIT OF LINER APPROXIMATE EDGE OF WATER REFERENCES 1. "EMBANKMENT & SOIL BORING MONITORING WELL SURVEY NIPSCO MICHIGAN CITY GENERATING STATION PT. NW 1/4, SEC. 29, T38N, R4W AND PT. NE 1/4, SEC. 30, T38N, R4W MICHIGAN TOWNSHIP, LAPORTE COUNTY INDIANA." BY MARBACH, BRADY & WEAVER, INC. DATED 7/8/ HORIZONTAL AND VERTICAL DATA FOR THIS SURVEY ARE BASED ON A SOLUTION DERIVED FROM GLOBAL POSITIONING SYSTEM (GPS) OBSERVATIONS PROCESSED A CONTINUOUSLY OPERATING REFERENCE STATION. THE COORDINATE SYSTEM IS US STATE PLANE 1983, NAD 1983 (CONUS), INDIANA WEST ZONE. GROUND ELEVATIONS ARE BASED UPON SAID INDOT SOLUTION AND ARE ON THE 1988 NORTH AMERICAN VERTICAL DATUM (NAD88). THIS ORTHOMETRIC ELEVATION WAS DERIVED UTILIZING THE MOST RECENT GEOID MODEL (GEOID12A). 3. REFERENCE STATION USED: INLP LAPORTE CORS ARP A' CLIENT NORTHERN INDIANA PUBLIC SERVICE COMPANY CONSULTANT YYYY-MM-DD DESIGNED PREPARED RAW RWC REVIEWED APPROVED MCM RAW PROJECT TITLE PROJECT NO SUBTITLE A 0 1'' = 60' NORTHERN INDIANA PUBLIC SERVICE COMPANY MICHIGAN CITY GENERATING STATION MICHIGAN CITY, INDIANA PRIMARY 2 FINAL CLOSURE GRADING PLAN REV. 0 EDGE OF WATER FEET FIGURE 3 IF THIS MEASUREMENT DOES NOT MATCH WHAT IS SHOWN, THE SHEET SIZE HAS BEEN MODIFIED FROM: ANSI B 0 1 in

17 630 A (WEST) A' (EAST) 630 ELEVATION (FT) B 5H : 1V (SOUTH) 630 2% APPROXIMATE TOP OF CCR SEDIMENT TOP OF FINAL COVER GEOMEMBRANE LINER CROSS SECTION A-A' TYPICAL FINAL CLOSURE SECTION 2H : 1V ELEVATION (FT) GEOCOMPOSITE DRAINAGE LAYER LINER SUBGRADE (6" MIN.) B' (NORTH) 630 LINER LINER LINER LINER LINER LINER LINER TYPICAL FINAL CLOSURE SECTION N.T.S. VEGETATIVE SUPPORT/ PROTECTION LAYER (18" MIN.) GEOMEMBRANE LINER CCR SUBGRADE (THICKNESS VARIES) TYPICAL FINAL CLOSURE SECTION 620 Path: \\manchester\cadd\drawings\2015\nipsco\temporary MCGS Storage\ File Name: Primary 2 Grading calcs figure Liner.dwg ELEVATION (FT) APPROXIMATE TOP OF CCR SEDIMENT TOP OF FINAL COVER CROSS SECTION B-B' A-A' GEOMEMBRANE LINER CLIENT CONSULTANT 5H : 1V 5H : 1V YYYY-MM-DD DESIGNED PREPARED REVIEWED APPROVED ELEVATION (FT) NORTHERN INDIANA PUBLIC SERVICE COMPANY RAW RWC MCM RAW PROJECT TITLE PROJECT NO HORIZONTAL SCALE: VERTICAL SCALE: SUBTITLE A 0 1'' = 60' NORTHERN INDIANA PUBLIC SERVICE COMPANY MICHIGAN CITY GENERATING STATION MICHIGAN CITY, INDIANA PRIMARY 2 CROSS SECTIONS 0 1'' = 20' REV FEET FEET FIGURE 4 IF THIS MEASUREMENT DOES NOT MATCH WHAT IS SHOWN, THE SHEET SIZE HAS BEEN MODIFIED FROM: ANSI B 0 1 in

18 Path: \\manchester\cadd\drawings\2015\nipsco\temporary MCGS Storage\ File Name: Primary 2.dwg CLIENT NORTHERN INDIANA PUBLIC SERVICE COMPANY CONSULTANT YYYY-MM-DD DESIGNED PREPARED MCM RWC REVIEWED APPROVED MCM RAW PROJECT NORTHERN INDIANA PUBLIC SERVICE COMPANY MICHIGAN CITY GENERATING STATION MICHIGAN CITY, INDIANA TITLE CLOSURE SCHEDULE PROJECT NO SUBTITLE A REV. 0 FIGURE 5 IF THIS MEASUREMENT DOES NOT MATCH WHAT IS SHOWN, THE SHEET SIZE HAS BEEN MODIFIED FROM: ANSI B 0 1 in

19 EXHIBIT A STATEMENT OF CERTIFICATION

20

21 Golder Associates Inc. 670 N. Commercial Street, Suite 103 Manchester, NH USA Tel: (603) Fax: (603) Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation