APPENDIX D MODELING AND DEPOSITION ANALYSIS

Transcription

1 APPENDIX D MODELING AND DEPOSITION ANALYSIS

2 Appendix D Ambient Air Quality Dispersion and Deposition Modeling Analyses Supporting a Permit to Install Application Eagle Project Located in Michigamme Township, Michigan for the Kennecott Eagle Minerals Company Prepared by: Horizon Environmental Corporation th Street SE, Suite One Grand Rapids, Michigan March 15, 2012

3 TABLE OF CONTENTS EXECUTIVE SUMMARY... IV 1 INTRODUCTION AIR QUALITY IMPACT ANALYSIS DISPERSION MODEL LAND USE CLASSIFICATION AND DISPERSION MODE AERODYNAMIC DOWNWASH EFFECTS RECEPTOR POINTS AND TERRAIN ELEVATIONS METEOROLOGICAL DATA SOURCE INPUT PARAMETERS AND EMISSION RATES PM 10 MODELING METHODOLOGY AND PREDICTED IMPACTS Comparison to Significant Impact Levels PSD Class II Increment Consumption NAAQS Compliance Demonstration PM 2.5 MODELING METHODOLOGY AND PREDICTED IMPACTS Comparison to Significant Impact Levels PSD Class II Increment Consumption NAAQS Compliance Demonstration NO 2 MODELING METHODOLOGY AND PREDICTED IMPACTS Atmospheric Transformation of NO x to NO Comparison to Significant Impact Levels NAAQS Compliance Demonstration LEAD MODELING METHODOLOGY AND PREDICTED IMPACTS NAAQS Compliance Demonstration TAC MODELING METHODOLOGY AND PREDICTED IMPACTS AIR DEPOSITION ANALYSIS IMPACTS TO THE SALMON TROUT RIVER WATERSHED Meteorological Data Source Input Parameters and Emission Rates Deposition Rates and Estimated Impacts to the Watershed IMPACTS TO SOILS Meteorological Data Source Input Parameters and Emission Rates Deposition Rates and Estimated Impacts to Soils...26 The Eagle Project i Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Technical Support Document Permit to Install Application Appendix D March 15, 2012

4 LIST OF FIGURES FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 LOCATION OF THE EAGLE PROJECT LOCATION OF BUILDINGS IN RELATION TO EMISSION POINTS RECEPTORS USED IN THE AIR QUALITY IMPACT ANALYSIS PROPERTY BOUNDARY AND NEARBY RECEPTOR POINTS LOCATION OF EMISSION SOURCES EXTENT OF THE 24-HOUR AND ANNUAL PM 10 SIGNIFICANT IMPACT AREA EXTENT OF THE 24-HOUR PM 2.5 SIGNIFICANT IMPACT AREA EXTENT OF THE 1-HOUR NO 2 SIGNIFICANT IMPACT AREA RECEPTORS USED IN THE SALMON TROUT RIVER WATERSHED DEPOSITION ANALYSIS LIST OF TABLES TABLE 1 AUER LAND USE CLASSIFICATION SCHEME TABLE 2 EMISSION SOURCES AND EXHAUST PARAMETERS (NON-ROADWAY SOURCES) TABLE 3 EMISSION SOURCES AND EXHAUST PARAMETERS (ROADWAY SOURCES) TABLE 4 REGULATED NSR POLLUTANT SOURCES AND POTENTIAL EMISSION RATES TABLE 5 COMPARISON OF MODELED PM 10 AND PM 2.5 IMPACTS TO THE SIGNIFICANT IMPACT LEVELS TABLE 6 AQD-PROVIDED SOURCES INCLUDED IN THE PSD INCREMENT TABLE 7 TABLE 8 TABLE 9 TABLE 10 TABLE 11 CONSUMPTION AND NAAQS COMPLIANCE DEMONSTRATION COMPARISON OF MODELED PM 10 AND PM 2.5 IMPACTS TO THE PSD INCREMENTS COMPARISON OF MODELED PM 10 AND PM 2.5 IMPACTS TO THE NAAQS COMPARISON OF MODELED NO 2 IMPACTS TO THE SIGNIFICANT IMPACT LEVELS COMPARISON OF MODELED NO 2 IMPACTS TO THE 1-HOUR NAAQS COMPARISON OF MODELED LEAD IMPACTS TO THE NAAQS TABLE 12 HEALTH-BASED SCREENING LEVEL COMPLIANCE USING THE RULE 227(1)(a) ALLOWABLE EMISSION RATE METHODOLOGY EMISSION SOURCES AND EMISSION RATES TAC AERMOD SIMULATIONS TABLE 13 TABLE 14 COMPARISON OF MODELED TAC IMPACTS AGAINST AQD-PUBLISHED SCREENING LEVELS The Eagle Project ii Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Technical Support Document Permit to Install Application Appendix D March 15, 2012

5 TABLE 15 TABLE 16 ASSESSMENT OF AIR DEPOSITION IMPACTS TO THE SALMON TROUT RIVER WATERSHED ASSESSMENT OF AIR DEPOSITION IMPACTS TO SOILS LIST OF ATTACHMENTS ATTACHMENT A ATTACHMENT B ATTACHMENT C ATTACHMENT D DISPERSION AND DEPOSITION MODELING INPUT AND OUTPUT FILES (DVD-ROM) SUMMARY OF POTENTIAL REGULATED NSR POLLUTANT AND TAC EMISSION ESTIMATES DATA SUPPORTING THE SALMON TROUT RIVER WATERSHED DEPOSITION ANALYSIS DATA SUPPORTING THE SOILS DEPOSITION ANALYSIS (DVD-ROM) The Eagle Project iii Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Technical Support Document Permit to Install Application Appendix D March 15, 2012

6 EXECUTIVE SUMMARY Ambient air quality dispersion and deposition modeling analyses have been conducted in support of a Permit to Install application covering changes to the Kennecott Eagle Minerals Company s Eagle Project in Michigamme Township, Michigan. The modeling analyses were conducted in accordance with relevant U.S. EPA and Michigan Department of Environmental Quality, Air Quality Division ( AQD ) modeling guidance and in accordance with the methodology described to and approved by the AQD during a pre-application meeting held in Lansing on June 28, The dispersion modeling analyses demonstrate that ambient air quality impacts associated with the proposed changes to the Eagle Project will be less than Prevention of Significant Deterioration increments, National Ambient Air Quality Standards, and health-based screening levels published under Michigan s Air Toxics Rules. Further, the deposition modeling analyses demonstrate that the proposed changes to the Eagle Project will not result in adverse impacts to surrounding soils or the Salmon Trout River Watershed. This technical report, which serves as Appendix D to the Permit to Install application, describes the applicable modeling requirements, details the methodology and databases used to conduct the modeling analyses, and presents the results of the modeling analyses. The Eagle Project iv Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Technical Support Document Permit to Install Application Appendix D March 15, 2012

7 1 INTRODUCTION On December 14, 2007, the Michigan Department of Environmental Quality ( MDEQ ), Air Quality Division ( AQD ) issued to Kennecott Eagle Minerals Company ( KEMC ) Permit to Install No (the Permit ) covering the installation and operation of a proposed nickel and copper mine in Michigamme Township, Michigan (the Eagle Project ) 1. Ambient air quality dispersion modeling analyses conducted prior to issuance of the Permit demonstrated that potential regulated New Source Review ( NSR ) pollutants and toxic air contaminants ( TACs ) associated with the Eagle Project would not threaten the Prevention of Significant Deterioration ( PSD ) increments, National Ambient Air Quality Standards ( NAAQS ) or health-based screening levels published under Michigan s Air Toxics Rules. Deposition analyses conducted prior to issuance of the Permit demonstrated that the Eagle Project would not result in adverse impacts to surrounding soils or the Salmon Trout River Watershed. Since issuance of the Permit, KEMC has refined the design of the Eagle Project. The proposed design changes, described in the Permit to Install application, will result in a substantial reduction in the potential to emit regulated NSR pollutants and TACs from the Eagle Project. A detailed emissions inventory for the Eagle Project, taking into account the proposed design changes, is provided in Appendix C of the Permit to Install application. As shown in the inventory, potential facility-wide emissions of regulated pollutants are now well under the significant emission rate thresholds promulgated under Rule (e) of Michigan s Administrative Rules for Air Pollution Control (PA 451 of 1994, as amended). Therefore, consistent with AQD policy 2, an air quality impact analysis demonstrating compliance with PSD increments and NAAQS is not required. Though estimated emissions are now well below the Rule (e) significant emission rate thresholds, ambient air quality dispersion modeling analyses of potential particulate matter ( PM 10 and PM 2.5 ), oxides of nitrogen ( NO x ), and lead emissions from the Eagle project have been conducted for informational purposes. The results of the air impact analyses demonstrate compliance with the following: The PM 10 PSD Class II increments and NAAQS; 1 The Permit was modified on July 14, 2011 (Permit to Install No A) to reflect the replacement of three generators with a single emergency generator. 2 Guidance for Determining When Modeling is Necessary, Interoffice Communication, Lynn Fiedler, AQD, March 19, The Eagle Project 5 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

8 The PM 2.5 PSD Class II increment and NAAQS; The nitrogen dioxide ( NO 2 ) PSD increment and NAAQS, including the recently promulgated 1-hour NO 2 NAAQS; and The lead NAAQS. Air quality impact analyses of potential TAC emissions from the Eagle Project have also been conducted and demonstrate compliance with the health-based screening levels of Rule (1). The air quality impact analyses were conducted in accordance with the procedures set forth in Rules (1)(a) and (c). Though particulate emissions have been substantially reduced as a result of the proposed design changes, deposition analyses have been re-conducted in a manner consistent with the conservative methodology established during the original permitting of the Eagle Project. The deposition analyses continue to demonstrate that the Eagle Project will not result in adverse impacts to surrounding soils or the Salmon Trout River Watershed. The ambient air quality dispersion and deposition modeling analyses presented in this technical report were conducted in accordance with applicable U.S. EPA and AQD modeling guidance and in accordance with the methodology described to and approved by the AQD during a pre-application meeting held in Lansing on June 28, The databases, methodology, and results of the dispersion modeling analyses are presented in Section 2. The databases, methodology, and results of the deposition modeling analyses are presented in Section 3. The dispersion and deposition modeling input and output files and related modeling database files are provided in electronic format (DVD-ROM) in Attachment A. This technical report serves as Appendix D to the Permit to Install application. The Eagle Project 6 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

9 2 AIR QUALITY IMPACT ANALYSIS Ambient air quality dispersion modeling analyses of potential PM 10, PM 2.5, NO x, and TAC emissions associated with the Eagle Project have been conducted in support of the Permit to Install application covering proposed design changes to the Eagle Project. The analyses were conducted in accordance with the applicable provisions of the following U.S. EPA and AQD modeling guidance: Michigan Administrative Rule ; Air Dispersion Modeling Guidance Document, AQD, September 2009; The Guideline on Air Quality Models, Appendix W, 40 CFR Part 51; AERMOD Implementation Guide, U.S. EPA, March 19, 2009; Guidance Concerning the Implementation of the 1-hour NO 2 NAAQS, U.S. EPA Memorandum, June 29, 2010; and Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1-hour NO 2 National Ambient Air Quality Standard, U.S. EPA Memorandum, March 1, Except where necessary to meet current U.S. EPA and AQD modeling guidance, the dispersion modeling analyses were conducted in a manner consistent with the modeling analyses conducted in support of the Permit 3. The dispersion model employed in the air quality impact analysis, relevant site area characteristics, databases prepared in support of the analyses, and the methodology and results of the analyses are summarized in the following sections. The location of the Eagle Project is shown in Figure 1. Copies of the dispersion modeling input and output files and related modeling database files are provided in electronic format (DVD-ROM) in Attachment A. 3 Certain changes to the modeling methodology were necessary and were pre-approved by the AQD in order to meet current U.S. EPA and AQD modeling guidance. For instance, the model simulations described in this document were conducted using AERMOD, which, since issuance of the Permit, has replaced ISC3 as the recommended model for industrial applications. The Eagle Project 7 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

10 2.1 DISPERSION MODEL The dispersion model simulations were conducted using the AMS/EPA Regulatory Model ( AERMOD, Release No ). AERMOD is currently recommended and approved by the U.S. EPA and the AQD for use in near-field modeling applications of industrial facilities. AERMOD is designed to simulate conditions associated with this compliance demonstration, including: Rural dispersion conditions; Flat, simple, and complex terrain; Varying meteorology, including calm wind conditions; Elevated point sources designed to good engineering practice ( GEP ) height, as well as point sources influenced by building downwash; Low-level fugitive particulate-emitting sources, including roadways and storage piles; Wet and dry deposition of particulates; Transport of less than 50 kilometers to the point of maximum impact; and Concentration estimates over short-term and annual averaging period. Consistent with U.S. EPA and AQD guidance, all AERMOD simulations were conducted in the Regulatory Default mode. 2.2 LAND USE CLASSIFICATION AND DISPERSION MODE Atmospheric conditions affecting the downwind dispersion of regulated NSR pollutants and TACs may be influenced by localized land use. As a result, AERMOD has been designed to simulate the downwind dispersion of these constituents under both rural and urban conditions. To assess whether to run AERMOD in rural or urban mode for a particular application, the Guideline on Air Quality Models suggests using either a population density procedure or a land use classification procedure employing a typing scheme developed by Auer 4. Of the two methods, the U.S. EPA considers the land use procedure to be the more definitive. The Auer land use classification procedure is conducted as follows: 4 Correlation of Land Use and Cover with Meteorological Anomalies, Journal of Applied Meteorology, The Eagle Project 8 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

11 1) Classify the land use within the total area, A o, circumscribed by a three kilometer radius circle around the source using Auer s land use typing scheme; 2) If land use type I1, I2, C1, R2, and R3 account for 50 percent or more of A o, operate AERMOD in urban mode; otherwise, set AERMOD to operate in rural mode. The Auer land use classification scheme is shown in Table 1. Consistent with U.S. EPA guidance, Auer s land use classification scheme was utilized to assess localized land use around the Eagle Project property. Based on U.S.G.S. topographic projections and aerial imagery, land use surrounding the Eagle Project property is clearly classified as rural. Therefore, the AERMOD simulations were conducted in rural mode. 2.3 AERODYNAMIC DOWNWASH EFFECTS Plumes emitted from new stacks with heights greater than the following good engineering practice ( GEP ) design formula are not expected to be influenced by nearby buildings or other structures: H g = H + 1.5L Where, H g is GEP stack height H is the height of the nearby building or structure L is the lesser dimension of the height or projected width of the nearby building or structure The proposed Mine Vent Air Raise ( MVAR ) stack has been designed to a height of meters (65 feet). When compared against the dimensions of nearby buildings and structures, the MVAR stack is classified as a GEP stack. Plumes emitted from stacks with heights less than GEP design may be influenced by nearby buildings or other structures. The remaining emission points (vertical stacks and horizontal vents/fans) will be built to a height less than GEP. In accordance with U.S. EPA and AQD guidance, the BPIP-PRIME aerodynamic downwash pre-processor (Release No ) was used to estimate the maximum projected lateral and vertical dimensions of those buildings or structures that could influence non-gep emission points on a wind The Eagle Project 9 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

12 direction-specific basis. The release height of all emission points associated with the Eagle Project are summarized in Table 2. BPIP-PRIME requires as input the dimensions of all existing and proposed buildings or structures that could potentially influence emissions from a stack that is located at a distance less than five times the lesser dimension of height or projected width of the nearby structure. Maximum projected lateral and vertical dimensions of influencing structures, as calculated by BPIP-PRIME, are subsequently input to AERMOD. The location and height of building structures in relation to emission points are illustrated in Figure RECEPTOR POINTS AND TERRAIN ELEVATIONS AERMOD-predicted concentrations may be estimated at discrete receptor locations. In accordance with U.S. EPA and AQD guidance, a discrete cartesian receptor grid was developed to a lateral extent sufficient to encompass significant impact areas generated by the regulated NSR pollutant simulations and of sufficient spatial density to identify maximum ambient impacts. The two primary sections of the Eagle Project property will be completely circumscribed by fencing, with guarded entrance points, designed to preclude unauthorized access to the property. Accordingly, receptors were located along the secured property boundary at distances not exceeding 25 meters. Additional receptor points were located off-property out to a distance of approximately 40 kilometers from the center of the Eagle Project property according to the following methodology: 25 meter spacing out to a distance of approximately one kilometer; 50 meter spacing out to a distance of approximately 1.5 kilometers; 100 meter spacing out to a distance of approximately 2.5 kilometers; and 500 meter spacing out to a distance of approximately 8 kilometers. This receptor grid, consisting of 10,358 discrete receptor points, is sufficient to identify the extent of PM 10, PM 2.5, and NO 2 significant impact areas ( SIAs ), and to identify maximum regulated NSR pollutant and TAC impacts. The full grid is displayed in Figure 3. Property boundary and nearby receptors are shown in Figure 4. Elevated terrain features may affect the transport of atmospheric contaminants as well as serve as areas of potentially higher pollutant impacts. Where appropriate, terrain features The Eagle Project 10 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

13 should be included in the modeling analysis. A review of topographic projection data reveals variations in terrain elevations in and around the Eagle Project property. Therefore, in accordance with the AERMOD Implementation Guide, terrain elevations for each modeled receptor point and emission source were obtained using the U.S. EPA s AERMAP preprocessor (Release No ) along with digital National Elevation Dataset terrain files, in North America Datum 83, obtained in GeoTIFF format from the U.S.G.S. Seamless Data Server. Terrain elevations generated by the AERMAP preprocessor were subsequently input to AERMOD. The AERMAP input and Output files are provided in electronic format (DVD-ROM) in Attachment A. 2.5 METEOROLOGICAL DATA When conducting model simulations to demonstrate compliance with PSD increments and NAAQS, the U.S. EPA and AQD require the use of the most spatially representative five-year meteorological database whenever site-specific meteorological data is not available 5. Site-specific meteorological data is not currently being collected at the Eagle Project site. Therefore, the nearest publicly available five-year meteorological database was used to conduct the PM 10, PM 2.5, and NO 2, and lead compliance demonstrations. The nearest publicly available meteorological database consists of surface observations measured at the National Weather Service ( NWS ) station located at the Sawyer International Airport in Gwinn, Michigan (Station No ), combined with coincident upper air observations measured at the NWS station located in Green Bay, Wisconsin (Station No ). Five years ( ) of the Sawyer/Green Bay database, preprocessed using the AERMET and AERSURFACE preprocessors by the AQD, were used in the PM 10, PM 2.5, NO 2, and lead compliance demonstrations. Pursuant to Rule , one year of the most spatially representative meteorological database may be used when conducting model simulations to demonstrate compliance with the screening level requirement of Michigan s Air Toxics Rules. Therefore, one year (2009) of the Sawyer/Green Bay database was used in the Rule compliance demonstration. 5 Though the form of the new NO 2 NAAQS is based on a 3-year average of the annual 98 th percentile of the 1-hour daily maximum concentrations, the U.S. EPA and AQD recommend the use of a five-year meteorological dataset when site-specific meteorological data is not available. The Eagle Project 11 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

14 2.6 SOURCE INPUT PARAMETERS AND EMISSION RATES Potential production-related emission sources associated with the Eagle Project include the MVAR, the Coarse Ore Storage Area ( COSA ) Building, the Aggregate Storage Building, the Backfill Plant, storage silos, and an emergency generator. Potential fugitive emission sources include the TDRSA pile and plant roadways. The MVAR, Aggregate Building baghouse, and emergency generators will vent through vertically unobstructed stacks. Exhaust fans located at the COSA Building and the Aggregate Storage Building will vent horizontally, as will the baghouse located at the Backfill Plant and bin vent filters on the storage silos. The stacks and horizontal exhaust fans are appropriately simulated as points sources. Point source exhaust parameters necessary for input to AERMOD consists of stack height, insider diameter, exit temperature, and exit velocity. Consistent with AQD guidance, all horizontal point sources were simulated with exit velocities limited to meters per second. Consistent with AQD guidance, the TDRSA pile was simulated in AERMOD as an elevated area source. Area source parameters necessary for input to AERMOD include release height, length, width, and the vertical spread of the source. One half of the anticipated height of the fully formed TDRSA pile was used to represent the release height. Consistent with AQD guidance, model simulations of the TDRSA pile were conducted assuming no vertical spread of the pile (σ z = 0). Consistent with AQD guidance, plant roadways were simulated in AERMOD as volume sources with parameters based on the following methodology: Release Height = (1.7 x Vehicle Height)/2 Initial Sigma Z = (1.7 x Vehicle Height)/2.15 Initial Sigma Y = Spacing/2.15 Point and area source exhaust parameters are summarized in Table 3, while volume source parameters for the various plant roadways are summarized in Table 4. The location of the potential emission sources is illustrated in Figure 5. The methodology for estimating potential short-term and annual source-specific emissions of regulated NSR pollutants and TACs associated with the Eagle Project is provided in the Permit to Install application. A summary of the potential emissions estimates is provided in Attachment B. The potential short-term and annual emission estimates were converted into The Eagle Project 12 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

15 gram per second emission rates for input to AERMOD. Source-specific regulated NSR pollutant emission rates input to AERMOD for the PSD increment and NAAQS compliance demonstration are summarized in Table 4. TAC emission rates considered in the Rule (1)(a) allowable emission rate analysis are presented in Table 12, while sourcespecific TAC emission rates input to AERMOD in the Rule (1)(c) compliance demonstration are shown in Table PM 10 MODELING METHODOLOGY AND PREDICTED IMPACTS Utilizing AERMOD over a five-year meteorological database ( Sawyer/Green Bay), dispersion model simulations were conducted to demonstrate that potential PM 10 emissions from process-related and fugitive sources associated with the Eagle Project will not result in an exceedance of the 24-hour and annual PSD Class II increment or the 24-hour NAAQS. The modeling methodology and resultant predicted impacts are summarized in the following sections. Note that model simulations were conducted conservatively assuming that depletion of the plume (i.e., lessening of concentrations) due to gravitational settling and depositional effects would not occur during transport Comparison to Significant Impact Levels As a first step in the compliance demonstration, potential 24-hour and annual PM 10 emissions associated with the Eagle Project were simulated using AERMOD. Resultant maximum predicted concentrations were then compared against the 24-hour and annual PSD significant impact levels ( SILs ) of 5 µg/m 3 and 1 µg/m 3, respectively. Pursuant to U.S. EPA guidance, if modeled impacts from a proposed source are less than the respective SIL, the proposed source is considered to have an insignificant impact on air quality and additional dispersion modeling analyses to demonstrate compliance with applicable PSD increments and NAAQS are not necessary. Maximum predicted 24-hour and annual average PM 10 concentrations due to the Eagle Project are summarized in Table 5. As shown in the table, the maximum predicted 24- hour average PM 10 concentration across the five-year meteorological database is 9.9 µg/m 3, which is above the SIL of 5 µg/m 3. The maximum predicted annual average PM 10 concentration across the five-year meteorological database is 1.3 µg/m 3, which is above the SIL of 1 µg/m 3. Maximum predicted 24-hour and annual average impacts for the MVAR stack are 2.7 µg/m 3 and 0.2 µg/m 3, respectively. The Eagle Project 13 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

16 Under U.S. EPA guidance, if initial model simulations of a proposed source result in maximum predicted concentrations above the SIL, comprehensive model simulations of the proposed source along with other emission sources in the area are typically conducted to assess PSD increment consumption and compliance with the NAAQS. As part of the comprehensive simulations, the modeling domain should be reduced to a circular area that extends from the source to the furthest receptor location where predicted impacts exceed the SIL. This area is identified as the Significant Impact Area ( SIA ). The extent of the 24-hour and annual SIA for the PM 10 simulations is illustrated in Figure 6. The comprehensive model simulations described below were conducted over receptor points located within the SIA PSD Class II Increment Consumption The U.S. EPA has established PSD Class II increments for PM 10 over both a 24-hour and an annual averaging period. Increment consumption is assessed by modeling the Eagle Project, along with nearby PM 10 -emitting and increment consuming sources that have the potential to impact the Eagle Project s SIA. In support of this analysis, the AQD provided the following inventory of additional PM 10 increment consuming sources: the Empire Iron Mine in Marquette (SRN: B1827), and the Wisconsin Electric Power Company facility in Marquette (SRN: B4261). Emissions and stack exhaust parameters for these two facilities are summarized in Table 6. In accordance with U.S. EPA guidance, compliance with the 24-hour PM 10 PSD increment has been demonstrated when the highest, 2 nd highest modeled 24-hour average concentration in each of the five years of meteorological data simulated is less than 30 µg/m 3. Compliance with the annual PM 10 PSD increment has been demonstrated when the modeled annual average concentration at all receptor points in each of the five years of meteorological data simulated is less than 17 µg/m 3. Pursuant to AQD guidance, an applicant may consume up to 80 percent of the PSD increment. The results of the PM 10 PSD increment consumption assessment are summarized in Table 7. As shown in the table, the highest, 2 nd highest 24-hour average PM 10 concentration across the five-year meteorological database is 8.2 µg/m 3, which is well under 80 percent of the 24-hour Class II increment of 30 µg/m 3. The maximum annual average PM 10 concentration across the five-year meteorological database is 4.2 µg/m 3, which is well under 80 percent of the annual Class II increment of 17 µg/m 3. Consequently, the Eagle Project is in compliance with PM 10 PSD Class II increments. The Eagle Project 14 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

17 2.7.3 NAAQS Compliance Demonstration The U.S. EPA has established a 24-hour PM 10 NAAQS of 150 µg/m 3. Compliance with the NAAQS is assessed by modeling the Eagle Project, along with nearby PM 10 -emitting sources that have the potential to impact the Eagle Project s SIA. The AQD has determined that the additional PM 10 sources used in the PSD increment consumption assessment and summarized in Table 6 should also be used in the NAAQS compliance demonstration. Modeled 24-hour concentrations are then combined with an ambient PM 10 background concentration (representing minor and distant sources) and compared against the NAAQS. There are currently no ambient PM 10 monitors operating in or near the Upper Peninsula, though the AQD currently operates six ambient PM 10 monitors in the Lower Peninsula. As a conservative measure, the highest recorded 24-hour concentration measured at the six ambient monitors 66 µg/m 3, measured at the Dearborn monitor 6 in 2010 was applied to the NAAQS compliance demonstration. In accordance with U.S. EPA guidance, compliance with the PM 10 NAAQS has been demonstrated when the highest, 6 th highest modeled 24-hour average concentration across the five-year meteorological database, combined with an ambient background concentration, is less than the NAAQS. The results of the NAAQS compliance demonstration are summarized in Table 8. As shown in the table, the highest, 6 th highest 24-hour average PM 10 concentration across the five-year meteorological database is 7.7 µg/m 3. Combined with a conservatively high ambient background concentration, the total concentration is 73.7 µg/m 3, which is well under the 24-hour PM 10 NAAQS of 150 µg/m 3. Consequently, the Eagle Project is in compliance with PM 10 NAAQS. 2.8 PM 2.5 MODELING METHODOLOGY AND PREDICTED IMPACTS Utilizing AERMOD over a five-year meteorological database ( Sawyer/Green Bay), dispersion model simulations were conducted to demonstrate that potential PM 2.5 emissions from process-related and fugitive sources associated with the Eagle Project will not result in an exceedance of the 24-hour PSD Class II increment or the 24-hour NAAQS. The modeling methodology and resultant predicted impacts are summarized in the following sections. 6 Monitor Site ID The Eagle Project 15 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

18 2.8.1 Comparison to Significant Impact Levels Consistent with the PM 10 simulations, potential 24-hour and annual PM 2.5 emissions were simulated using AERMOD and resultant maximum predicted concentrations were compared against the 24-hour and annual average SILs of 1.2 µg/m 3 and 0.3 µg/m 3, respectively. Maximum predicted 24-hour and annual average PM 2.5 concentrations due to the Eagle Project are summarized in Table 5. As shown in the table, the maximum predicted 24-hour average PM 2.5 concentration across the five-year meteorological database is 1.4 µg/m 3, which is slightly above the 24-hour SIL. The maximum predicted annual average PM 2.5 concentration across the five-year meteorological database is 0.16 µg/m 3, which is less than the annual SIL. Maximum predicted 24-hour and annual average impacts for the MVAR stack are 1.1 µg/m 3 and 0.05 µg/m 3, respectively. Under U.S. EPA guidance, if initial model simulations of a proposed source are less than the SIL, the source has an insignificant impact on air quality and no additional model simulations are required. Therefore, additional PM 2.5 model simulations were limited to the 24-hour averaging period. The extent of the 24-hour average SIA is illustrated in Figure 7. The comprehensive model simulations described below were conducted over receptor points located within the SIA PSD Class II Increment Consumption The U.S. EPA has established a PM 2.5 PSD Class II increment 9 µg/m 3. Increment consumption is assessed by modeling the Eagle Project, along with nearby PM 2.5 -emitting and increment consuming sources that have the potential to impact the Eagle Project s SIA. The inventory of additional particulate-emitting increment consuming sources provided by the AQD does not include emissions in the PM 2.5 fraction. Therefore, as a conservative measure, the model simulations were conducted assuming that AQD-provided inventory of additional PM 10 increment consuming sources (SRNs: B1827 and B4261) have the potential to emit an equivalent amount of PM 2.5. Emissions and stack exhaust parameters for these two facilities are summarized in Table 6. In accordance with U.S. EPA guidance, compliance with the 24-hour PM 2.5 PSD increment has been demonstrated when the highest, 2 nd highest modeled 24-hour average concentration in each of the five years of meteorological data simulated is less than 9 µg/m 3. Pursuant to AQD guidance, an applicant may consume up to 80 percent of the PSD increment. The Eagle Project 16 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

19 The results of the PM 2.5 PSD increment consumption assessment are summarized in Table 7. As shown in the table, the highest, 2 nd highest 24-hour average PM 2.5 concentration across the five-year meteorological database is 3.3 µg/m 3, which is well under 80 percent of the 24-hour Class II increment of 9 µg/m 3. Consequently, the Eagle Project is in compliance with PM 2.5 PSD Class II increment NAAQS Compliance Demonstration The U.S. EPA has established a 24-hour PM 2.5 NAAQS of 35 µg/m 3. Compliance with the NAAQS is assessed by modeling the Eagle Project, along with nearby PM 2.5 -emitting sources that have the potential to impact the Eagle Project s SIA. The AQD has determined that the additional particulate-emitting sources used in the PSD increment consumption assessment and summarized in Table 6 should also be used in the NAAQS compliance demonstration. Modeled 24-hour concentrations are then combined with an ambient PM 2.5 background concentration (representing minor and distant sources) and compared against the NAAQS. A representative 24-hour PM 2.5 concentration of 29.3 µg/m 3 has been provided by the AQD 7. In accordance with U.S. EPA guidance, compliance with the PM 2.5 NAAQS has been demonstrated when the 98 th percentile of the 24-hour concentration across the five-year meteorological database, combined with an ambient background concentration, is less than the NAAQS. The results of the NAAQS compliance demonstration are summarized in Table 8. As shown in the table, the 98 th percentile of the 24-hour average concentration across the five-year meteorological database is 2.1 µg/m 3. Combined with the ambient background concentration, the total concentration is 31.4 µg/m 3, which is less than the 24-hour PM 2.5 NAAQS of 35 µg/m 3. Consequently, the Eagle Project is in compliance with PM 2.5 NAAQS. 2.9 NO 2 MODELING METHODOLOGY AND PREDICTED IMPACTS Utilizing AERMOD over a five-year meteorological database ( Sawyer/Green Bay), dispersion model simulations were conducted to demonstrate that potential NO x emissions from process sources associated with the Eagle Project will not result in an exceedance of the annual NO 2 PSD increment, the annual NO 2 NAAQS, or the recently 7 24-Hour PM 2.5 concentrations measured at the Sault Ste. Marie, Ontario ambient monitor during the years 2004 through The Eagle Project 17 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

20 promulgated 1-hour NO 2 NAAQS 8. The modeling methodology and resultant predicted impacts are summarized in the following sections. As detailed in Attachment B, the Eagle Project has the potential to emit NO x from mine heaters, blasting, and an emergency generator. Of the three emission sources, the heaters represent the only sources that may operate in a consistent matter during a 24-hour period. Underground blasting will occur no more than once per day, with emissions occurring on the order of only a few minutes. Therefore, blasting emissions were not included in the NO 2 compliance demonstration. Modeling of the emergency generator, which is also an intermittent source, was conducted in support of Permit to Install No A. For consistency purposes, modeling of the emergency generator was conducted in this analysis Atmospheric Transformation of NO x to NO 2 In accordance with U.S. EPA guidance, atmospheric transformation of NO x to NO 2 during transport was simulated by AERMOD following the plume volume molar ratio method ( PVMRM ) approach. To conduct the PVMRM calculation, AERMOD requires as input an NO 2 /NO x ambient equilibrium ratio, an in-stack NO 2 /NO x ratio, and coincident hourly ambient ozone concentrations. Consistent with the AQD-approved model simulations of the emergency generator in 2011, an NO 2 /NO x ambient equilibrium ratio of and an instack NO 2 /NO x ratio of 0.1 were input to AERMOD. Representative coincident hourly ozone concentrations, necessary to assess the transformation of NO x to NO 2 during plume transport, were provided by the AQD 9 and input to AERMOD Comparison to Significant Impact Levels Potential 1-hour and annual average NO x emissions were simulated and resultant maximum predicted NO 2 concentrations were compared against the 1-hour and annual average SILs of 7.6 µg/m 3 and 1 µg/m 3, respectively. Maximum predicted 1-hour and annual average NO 2 concentrations due to the Eagle Project are summarized in Table 9. As shown in the table, the maximum predicted 1-hour NO 2 concentration across the fiveyear meteorological database is 36.4 µg/m 3, which is above the 1-hour SIL. The maximum predicted annual average NO 2 concentration across the five-year meteorological database is 0.52 µg/m 3, which is less than the annual SIL. Therefore, the 8 On January 22, 2010, the U.S. EPA promulgated a 1-hour NO 2 NAAQS that became effective on April 12, Hourly ozone concentrations measured at the Sault Ste. Marie, Ontario ambient monitor during the years 2005 through The Eagle Project 18 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

21 Eagle Project has an insignificant impact on NO 2 air quality over an annual averaging period and no additional annual average model simulations are required. The extent of the 1-hour NO 2 SIA is illustrated in Figure 8. Within the SIA, comprehensive model simulations of the Eagle Project along with other sources in the area were conducted to demonstrate compliance with the 1-hour NAAQS. The U.S. EPA has not yet promulgated a 1-hour PSD increment for NO NAAQS Compliance Demonstration The U.S. EPA has established a 1-hour NO 2 NAAQS of 188 µg/m 3 (100 ppb). Compliance with the NAAQS is assessed by modeling the Eagle Project, along with nearby NO x -emitting sources that have the potential to impact the Eagle Project s SIA. In support of the NAAQS compliance demonstration, the AQD provided the following inventory of additional NO x -emitting sources: the Empire Iron Mine in Marquette (SRN: B1827), the Wisconsin Electric Power Company facility in Marquette (SRN: B4261), and the Tilden Mine in Ishpeming (SRN: B4885). Inventory information for an additional NOx-emitting source in the area, the Marquette Board of Light and Power (SRN: B1833) was obtained from the source s Renewable Operating Permit and included in the NAAQS compliance demonstration. Emissions and stack exhaust parameters for these four facilities are summarized in Table 6. Modeled 1-hour concentrations are then combined with an ambient NO 2 background concentration (representing minor and distant sources) and compared against the NAAQS. A representative 1-hour NO 2 concentration of 66.5 µg/m 3 has been provided by the AQD 10. In accordance with U.S. EPA guidance, compliance with the NO 2 NAAQS has been demonstrated when the modeled five year average of the 8 th highest daily 1-hour maximum NO 2 concentration, combined with the coincident 1-hour monitored NO 2 concentration, against the 1-hour NAAQS of 188 µg/m 3. The results of the NAAQS compliance demonstration are summarized in Table 10. As shown in the table, the 98 th percentile of the 1-hour average concentration across the five-year meteorological database is µg/m 3. Combined with the ambient background concentration, the total concentration is µg/m 3, which is below the 1-hour NO 2 NAAQS of 188 µg/m 3. Consequently, the Eagle Project is in compliance with the 1-hour NO 2 NAAQS. 10 Daily NO 2 concentrations measured at the Sault Ste. Marie, Ontario ambient monitor during the years 2005 through The Eagle Project 19 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

22 2.10 LEAD MODELING METHODOLOGY AND PREDICTED IMPACTS Utilizing AERMOD over a five-year meteorological database ( Sawyer/Green Bay), dispersion model simulations were conducted to demonstrate that potential lead emissions from process sources associated with the Eagle Project will not result in an exceedance of the rolling 3-month lead NAAQS. There are currently no U.S. EPAestablished SILs or PSD increments for lead. The modeling methodology and resultant predicted impacts are summarized in the following sections. Note that model simulations were conducted conservatively assuming that depletion of the plume (i.e., lessening of concentrations) due to gravitational settling and depositional effects would not occur during transport NAAQS Compliance Demonstration The U.S. EPA has established a rolling 3-month lead NAAQS of 0.15 µg/m 3. Compliance with the NAAQS was demonstrated by modeling the Eagle Project over a fiveyear meteorological database (Sawyer/Green Bay) to predict rolling 3-month average lead concentrations across the modeling domain. The U.S. EPA s LEADPOST post-processor was then employed to identify the maximum 3-month rolling average lead concentration during each of the five years. Modeled rolling 3-month average lead concentrations were then combined with an ambient lead background concentration (representing minor and distant sources) and compared against the NAAQS. There are currently no ambient lead monitors operating in or near the Upper Peninsula, though the AQD currently operates four ambient lead monitors in the Lower Peninsula. As a conservative measure, the highest recorded rolling 3-month average lead concentration measured at the Dearborn monitor in µg/m 3 was applied to the NAAQS compliance demonstration. The results of the lead NAAQS compliance demonstration are summarized in Table 11. As shown in the table, the maximum rolling 3-month average lead concentration across the five-year meteorological database is µg/m 3. Combined with a conservatively high ambient background concentration, the total concentration is 0.02 µg/m 3, which is well under the lead NAAQS of 0.15 µg/m 3. Consequently, the Eagle Project is in compliance with lead NAAQS. 11 Monitor Site ID The Eagle Project 20 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

23 2.11 TAC MODELING METHODOLOGY AND PREDICTED IMPACTS Rule requires new or modified sources of TAC emissions to demonstrate that the ambient impact of each regulated TAC emitted is less than its corresponding initial threshold screening level ( ITSL ), initial risk screening level ( IRSL ), or both if applicable. Pursuant to Rule (1)(a), compliance with the screening level requirement may be demonstrating by conducting an allowable emission rate analysis, whereby an allowable emission rate is estimated on a per-tac basis, based on the TACspecific screening level and averaging period associated with that TAC. If the potential to emit of a TAC emitted from a new or modified source is below the allowable emission rate estimated using the Rule (1)(a) methodology, then the source is in compliance with the screening level requirement of Rule for that TAC. If the potential to emit of a TAC is above the allowable emission rate, refined analyses using dispersion modeling may be conducted pursuant to Rule (1)(c). The AQD has developed a calculation table for conducting the Rule (1)(a) allowable emission rate analysis. Potential TAC emissions associated with process and fugitive sources at the Eagle Project 12 have been entered into the calculation table, which is included as Table 12. As shown in the table, all but two TACs potentially emitted from the Eagle Project comply with the health-based screening level requirement through the allowable emission rate methodology. Utilizing AERMOD over a one-year meteorological database (2009 Sawyer/Green Bay), dispersion model simulations of the two remaining TACs arsenic and nickel were conducted and resultant predicted concentrations were compared against their respective AQD-published screening levels. Potential process unit-specific and fugitive emission rates for these two TACs are summarized in Table 13, while maximum predicted impacts are summarized in Table 14. As shown in the table, the maximum predicted annual average nickel impact of µg/m 3 is well under its corresponding IRSL of µg/m 3. The maximum predicted annual average arsenic impact of µg/m 3 is above its corresponding IRSL of µg/m 3 over a limited number of receptor points located along and adjacent to the eastern property boundary. Pursuant to Rule (2), compliance with the health-based screening level requirement is demonstrated when impacts due to facility-wide emissions of a TAC are less than its corresponding secondary risk screening 12 Compliance with the screening level requirement for TACs potentially emitted from the proposed emergency generator was demonstrated as part of the application for Permit to Install No A. Therefore, the analysis has not been repeated as part of this submittal. The Eagle Project 21 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

24 level ( SRSL ). As shown in Table 14, the maximum predicted annual average facilitywide arsenic impact of µg/m 3 is well under its corresponding SRSL of µg/m 3. Utilizing the procedures of Rule (1)(a) and (c), compliance with the health-based screening level requirement of Rule 225 has been demonstrated for the Eagle Project. Though there is no published screening level for mercury, model simulations of potential mercury emissions associated with the Eagle Mine were conducted for informational purposes. As shown in Table 14, the maximum predicted annual average mercury impact is µg/m 3. The Eagle Project 22 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

25 3 AIR DEPOSITION ANALYSIS Air deposition modeling analyses of emission sources associated with the Eagle Project have been conducted in support of the Permit to Install application. The conservativelybased deposition modeling analyses demonstrate that: Metals deposition will not result in adverse impacts to the Salmon Trout River Watershed; and Metals deposition will not result in adverse impacts to surrounding soils. Note that with the proposed design changes, described in the Permit to Install application, potential metals emissions associated with the Eagle Project have been substantially reduced. The methodology and results of the deposition analyses conducted in support of the PTI application are presented below. 3.1 IMPACTS TO THE SALMON TROUT RIVER WATERSHED Utilizing AERMOD and the conservative methodology employed by AQD modeling and toxicology staff prior to issuance of the Permit, simulations of potential nickel and copper emissions from underground mining operations 13 were conducted to assess deposition to the Salmon Trout River Watershed. Model simulations were conducted over the receptor grid developed by AQD modeling staff to cover the 36 square mile area that drains to the Salmon Trout River at the point Latitude , Longitude Consistent with the AQD s original analysis, this analysis was conducted under the impracticable assumption that 100 percent of the total nickel and copper mass deposited per year in the 36 square mile area will dissolve in water and drain to the Salmon Trout River at the single point and when the river is flowing at its lowest 95 percent rate 14. The location of the Salmon Trout River Watershed and modeled receptor points is shown in Figure Simulations conducted in support of the Permit in 2007 included potential metals emissions associated with above-ground crushing operations. However, ore crushing is no longer planned for the Eagle Project. 14 The lowest 95 percent flow rate of 27 cubic feet per second occurs in August. MDEQ Land and Water Management Division. The Eagle Project 23 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

26 3.1.1 Meteorological Data Model simulations were conducted using two years of the Sawyer/Green Bay meteorological database ( ). In order to estimate deposition during wet atmospheric conditions, the meteorological data input to AERMOD should include measured precipitation. However, a review of the Sawyer surface observations indicates that precipitation may not have been consistently (or properly) measured during the two year period. Therefore, to ensure that deposition impacts are not under-predicted, coincident precipitation observations recorded over the two year period at the Munising Airport (Station No ) were extracted and inserted into the Sawyer/Green Bay database Source Input Parameters and Emission Rates For deposition simulations, AERMOD requires as input the emission rate, stack exhaust parameters, particle size diameter, and particle density. Emissions of nickel and copper generated underground will vent through the MVAR stack. The MVAR will have a potential to emit 13.1 pounds per year of nickel and 11.4 pounds per year of copper. Stack exhaust parameters for the MVAR are summarized in Table 2. In its original analyses, the AQD used data published in Category 3, Table B.2.2 of AP- 42 to develop a suite of 16 particle size diameter categories. To remain consistent, the same methodology was employed in this modeling demonstration. The particle size diameters and the mass fraction of each particle size input to AERMOD for the deposition simulation are summarized in Attachment C. The mined ore has a density of approximately 3.6 grams per cubic centimeter Deposition Rates and Estimated Impacts to the Watershed Utilizing AERMOD over the two year meteorological database, annual deposition rates of nickel and copper were predicted over all receptor points in the modeling domain. Deposition rates were tabulated and summed to assess the total deposition across the Salmon Trout River Watershed modeling domain, on a per year basis. Total deposition of nickel and copper, in grams per year, are summarized in Attachment C. The maximum total nickel and copper deposition to the Salmon Trout River Watershed from the two-year simulation was then converted to a water concentration impact using the methodology and formulation table developed by the AQD. The nickel and copper The Eagle Project 24 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

27 water concentration impacts were then compared against their Lowest Final Chronic Values ( FCVs ). The results of the analysis are presented in Table 15. As shown in the table, nickel and water concentration levels are well below their FCVs. Therefore, the results of the conservatively-based deposition analysis demonstrate that potential nickel and copper emissions due to underground mining operations associated with the Eagle Project will not have an adverse impact on the Salmon Trout River Watershed. Moreover, if all of the nickel and copper emissions associated with the Eagle Project were to be deposited directly into the river (i.e., no modeling to assess the direction of transport and depletion of the plume as it disperses downwind), water concentration impacts would still be well below the FCVs. 3.2 IMPACTS TO SOILS Utilizing AERMOD and the conservative methodology employed by AQD modeling staff prior to issuance of the Permit, simulations of potential emissions of six target metals arsenic, cobalt, copper, manganese, nickel, and selenium emissions from underground mining operations 15 were conducted to assess deposition to soils surrounding the Eagle Project property. Model simulations were conducted over the receptor grid developed in support of the regulated NSR pollutant and TAC simulations described in Section 2.4. Soils metal concentrations were calculated under the following conservative assumptions: Deposited metals will mix homogenously in the top one centimeter of exposed soils; and Deposited metals will remain n the topsoil compartment and continue to accumulate over 10 years Meteorological Data Consistent with the Salmon Trout River Watershed impact analysis, model simulations were conducted using two years of the Sawyer/Green Bay meteorological database ( ), with coincident precipitation observations recorded over the two year period at the Munising Airport. 15 Simulations conducted in support of the Permit in 2007 included potential metals emissions associated with above-ground crushing operations. However, ore crushing is no longer planned for the Eagle Project. The Eagle Project 25 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

28 3.2.2 Source Input Parameters and Emission Rates For deposition simulations, AERMOD requires as input the emission rate, stack exhaust parameters, particle size diameter, and particle density. Emissions of the six target metals generated underground will vent through the MVAR stack. The MVAR will have a potential to emit 1.3 pounds per year of arsenic, 0.71 pounds per year of cobalt, 11.4 pounds per year of copper, 16.7 pounds per year of manganese, 13.1 pounds per year of nickel, and 0.04 pounds per year of selenium. Stack exhaust parameters for the MVAR are summarized in Table 2. Modeled particle size diameters, associated mass fractions, and particle density remained consistent with the Salmon Trout River Watershed impact analysis, with the exception of the particle density parameter for the arsenic and manganese simulations. The primary source of arsenic and manganese emissions venting through the MVAR stack is vehicle traffic on development rock/aggregate underground surfaces. The development rock has a density of approximately 2.84 grams per cubic centimeter. Therefore, this particle density was used in the arsenic and manganese simulations. The remaining ore-based metals were modeled at the ore density of 3.6 grams per cubic centimeter Deposition Rates and Estimated Impacts to Soils Utilizing AERMOD over the two year meteorological database, annual deposition rates of the six target metals were predicted over all receptor points in the modeling domain. Deposition rates were tabulated for each receptor point in the modeling domain, on a per year basis. For each target metal, the maximum of the annual deposition rate across the modeling domain was then divided by the soil density (1.6 grams per cubic centimeter) to identify a maximum annual metal-in-soil concentration level. The maximum impact was then extrapolated to a long-term metal-in-soil concentration level by assuming constant soil accumulation over a 10-year period. Consistent with the soil deposition analysis conducted by the AQD in 2007, the resulting soil concentration of each metal was then compared against available site-specific background soil levels provided by the MDEQ s Resource Management Division, soil cleanup criteria established by the MDEQ s Remediation Division, and risk criteria for metals in soils published by the U.S. Department of Interior, Bureau of Land Management. The results of the soils deposition analysis for the six target metals are compared against the three criteria in Table 16. Receptor-specific deposition rates are provided in electronic format (DVD-ROM) in Attachment D. The Eagle Project 26 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

29 As shown in the table, the 10-year maximum incremental soil concentration for each target metal are generally orders of magnitude less than the site-specific background soil level, soil cleanup criteria, and risk criteria for metals in soils. Therefore, the results of the conservatively-based deposition analysis demonstrate that potential metals emissions due to underground mining operations associated with the Eagle Project will not have an adverse impact on soils. The Eagle Project 27 Kennecott Eagle Minerals Company Proposed Nickel and Copper Mine Supporting Information Permit to Install Application Appendix D March 15, 2012

30 FIGURES

31 G:\gis\Country\USA\state\MI\projects\kennecott\layouts\figure_1_location_KEX0103.mxd - JLM V U ± Keweenaw County Houghton County Lake Superior Eagle Project Location Baraga County 41 Marquette County 28 U V Ishpeming Marquette Negaunee 28 V U 95 V U Legend 35 V U Figure 1 Location of the Eagle Project Kennecott Eagle Minerals Company Marquette County, Michigan Miles Dickinson County Newkirk Property Boundary County Iron County Boundary City Boundary Highway March 2012 Major Road Marquette County

32 Backfill Plant Vent Aggregate Baghouse Vent Silo Vents Aggregate Storage Building Vents Powerhouse Vent Coarse Ore Storage Building Vents Figure 2 Location of Buildings in Relation to Emission Points Kennecott Eagle Minerals Company Marquette County, Michigan March 2012

33 Figure 3 Receptors Used in the Air Quality Impact Analysis Kennecott Eagle Minerals Company

34 G:\gis\Country\USA\state\MI\projects\kennecott\layouts\figure_4_nearby_receptors_KEX0103.mxd - JLM ± ip Tr A le Rd Modeled Receptor Stack / Vent Eagle Building Property Boundary Road 0 March Figure 4 Property Boundary and Nearby Receptor Points Kennecott Eagle Minerals Company Marquette County, Michigan ,080 Feet Newkirk Legend Marquette County

35 G:\gis\Country\USA\state\MI\projects\kennecott\layouts\figure_5_emission_sources_KEX0103.mxd - JLM ± ip Tr A le Rd Emission Points Roadway Emission Source Road Eagle Building Property Boundary 0 March Figure 5 Location of Emission Sources Kennecott Eagle Minerals Company Marquette County, Michigan ,000 Feet Newkirk Legend Marquette County