Green River Soda Ash Plant

ANALYSIS OF EMISSION CONTROL MEASURES RELATIVE TO REGIONAL HAZE

January 8, 2020 1. Introduction The Solvay facility is an existing underground trona mine with surface processing facilities. The trona ore is processed into numerous sodium-based products. A detailed description of the facility and the associated emission points can be found in Section 2.0 Facility and Project Description of the Technical Support for PSD Permit Modification Application – ARGO Production Increase Project document included as Addendum A of this analysis document. The entirety of Addendum A document describes the complexity of the proposed ARGO Project – DEQ Application No. A0008829.

In summary, the ARGO Production Increase Project includes  Installing a new 200 ton per hour soda ash product dryer,  Installing a new “E” train dryer area baghouse,  Installing a MVR crystallizer, centrifuges, pumps, and associated piping and making other minor operational and equipment change to debottleneck productions in other ways,  Converting the existing coal-fire “A” and “B” calciners to natural gas combustion, and increasing the permitted throughput from 160 tph to 200 tph for each calciner,  Converting the existing coal-fired boilers to natural gas combustion, and  Increasing the permitted through put for the existing DR-6 product dryer from 161 tph soda ash to 200 tph soda ash with no modification.

The emissions of concern that will be assessed and discussed in this document are PM10, SO2 and

NOx.

2. Methodology The Four-Factor Analysis, results of which will be discussed below, will be based on:  Cost: The total cost of modifications associated with the coal – to – natural gas combustion conversion of two calciners and two boilers related to the decrease in Q (tons

per year of PM10, SO2 and NOx).  Time: The total time, from permit approval, until the conversion of the four combustion units is completed, using a phased construction schedule.  Energy and non-environmental impacts: The expected reduction in energy consumption and coal combustion waste related to the coal – to – natural gas combustion conversion.  Remaining useful life: The expected life of the converted combustion units.

3. Analysis  Cost: The projected cost of the coal – to – natural gas combustion conversion of the two calciners and two boilers is approximately $16.5M. Appendix F; Class I Area FLAG Initial Criteria Screening Analysis in Addendum A of this document discusses the analysis of Q (tons

per year of PM10, SO2 and NOx) for the proposed ARGO Project relative to the nearest Class 1 Area (Bridger Wilderness Area). The total emissions Q calculated in the FLAG analysis was 996 tons per year. The relative distance from the Solvay facility to the Bridger Wilderness Area is 131 km. Subsequently, the calculated Q/d for the proposed ARGO Project is 7.6. This is a 5.1 reduction in Q/d from the 12.69 documented by the Western Regional Air Partnership (WRAP). The 666 tons per year Q reduction from WRAP (1,662 tons per year) to the proposed ARGO project (996 tons per year) equates to a $2,500 cost per ton of reduced emissions as a result of the ARGO Project.  Time: The conversion of the calciners and boilers as proposed in the ARGO Project will take place in a phased progression over approximately four years. The calciners will be individually converted, followed by the boilers. If the application for the ARGO Project is approved on or about January 1, 2020, the final boiler conversion will be planned for completion by the end of 2023.  Energy and non-air environmental impacts: The conversion from coal – to – natural gas combustion is expected to result in an approximate 34% reduction in energy use for the boilers and 6% reduction for the calciners. The amount of coal combustion related waste that normally is disposed of either underground or in the tails pond will be eliminated.  Remaining useful life: The existing calciners and boilers that are targeted for coal – to – natural gas combustion conversion were initially installed in 1980. With the proposed conversion it is projected that they would remain useful for another 20 years or until replaced by a more efficient and cost-effective heat source.

4. Conclusions The proposed ARGO Production Increase Project will result in a 666 tons per year reduction in

total Q emissions (PM10, SO2 and NOx) by the coal – to – natural gas combustion conversion of two calciners and two boilers. The subsequent reduction in Q/d from 12.69 to 7.6 places the Solvay facility below the WRAP Q/d threshold of concern of 10. The total emissions reductions resulting from the implementation of the proposed ARGO Production Increase Project are described in detail in Addendum A of this document. The Class 1 FLAG Initial Screening Criteria Analysis for the ARGO Project is discussed in detail in Appendix F of Addendum A.

Addendum A

Technical Support for PSD Permit Modification Application – ARGO Production Increase Project

Technical Support for PSD Permit Modification Application

ARGO Production Increase Project

PREPARED FOR:

SOLVAY SODA ASH JV

PROJECT NO. 170-18-1 JUNE 4, 2019

CONTENTS PAGE

1.0 Introduction ...... 7 2.0 Facility and Project Description ...... 11 3.0 PSD Applicability Analysis ...... 14 3.1 Net Emissions Increase from Project ...... 14 3.2 Contemporaneous Sources ...... 18 4.0 Area Designation and Applicable Air Pollution Control Requirements ...... 20 4.1 Federal Regulations ...... 20 4.1.1 Calciners ...... 20 4.1.2 Natural Gas-Fired Boilers ...... 20 4.1.3 Soda Ash Product Crushing, Screening, and Transfers ...... 22 4.1.4 Product Dryer ...... 22 4.2 Wyoming Department of Environmental Quality Air Quality Division Standards and Regulations 23 4.2.1 Chapter 5: National Emission Standards ...... 23 4.2.2 Chapter 6: Permitting Requirements ...... 23 4.2.3 Chapter 7: Monitoring Regulations ...... 24 5.0 Proposed Controls – BACT ...... 26 6.0 Air Quality Impact Evaluation – Class II Areas ...... 27 6.1 Ambient Air Quality Standards ...... 28 6.2 General Modeling Approach ...... 28 6.3 Emission Characterization for Modeling ...... 29 6.3.1 Emissions for the SIA Analysis ...... 33 6.3.2 Emissions for the NAAQS and Increment Analyses ...... 38

6.3.3 Emissions for the PM2.5 Increment Analysis ...... 46 6.4 Source Characterization for Modeling ...... 53 6.5 Modeling Methodology ...... 61 6.5.1 Model Selection ...... 61 6.5.2 Meteorological Data ...... 61 6.5.3 Receptor Grid ...... 61 6.5.4 Background Concentrations ...... 64

6.5.5 Secondary PM2.5 Formation ...... 65 6.6 Nearby/Competing Sources ...... 73 6.7 Modeling Results ...... 74 6.7.1 Preliminary Analysis Results ...... 74

ii 6.7.2 Full Impact Modeling Results ...... 76 7.0 Air Quality Impact Evaluation – Class I Areas ...... 80 7.1 Class I Areas with Respect to Solvay Facility ...... 80 7.2 Class I Area Air Quality Related Values (AQRV) Analysis ...... 81 7.3 Class I PSD Increment Analysis ...... 82 8.0 PSD Additional Impacts Analysis ...... 83 8.1 Growth Analysis ...... 83 8.2 Soil and Vegetation Impacts ...... 83 8.2.1 Soils Survey ...... 83 8.2.2 Vegetation Survey ...... 85 8.2.3 Modeled Impacts to Soils and Vegetation ...... 86 8.3 Visibility Impairment Analysis ...... 87 9.0 Ozone Assessment ...... 88 10.0 Inhalation Risk Assessment ...... 90

Tables Table 2-1. List of ARGO Project Sources: New, Modified, and Debottlenecked Sources ...... 12 Table 3-1. Emissions Increases from ARGO Project ...... 17 Table 6-1. Applicable Class II Ambient Air Quality Standards, Increments, and SILs ...... 28 Table 6-2. Solvay Source List, with Annual Operation, Type, Model Run Status ...... 30 Table 6-3. SIA Emissions: Short-term PM ...... 35 Table 6-4. SIA Emissions: Long-term PM ...... 36 Table 6-5. SIA Emissions: Short-term CO ...... 37 Table 6-6. Modeled Emission Rates – Solvay Facility; CO PTE Emissions ...... 39 Table 6-7. Modeled Emission Rates – Solvay Facility; Particulate PTE Emissions ...... 40 Table 6-8. Modeled Emission Rates – Solvay Facility Emergency and Fugitive Sources; Particulate PTE Emissions ...... 43

Table 6-9. Generic PM2.5/PM10 Mass Fractions for Baghouses ...... 44

Table 6-10. 24-Hour PM2.5 Increment Consuming Sources at the Solvay Facility ...... 49

Table 6-11. Annual PM2.5 Increment Consuming Sources at the Solvay Facility ...... 51 Table 6-12. Source Release Parameters – Solvay Facility ...... 54 Table 6-13. Source Coordinates and Elevations ...... 59 Table 6-14. Background Values Utilized in Impact Analysis...... 64

Table 6-15. Solvay PM2.5 Precursor Emissions ...... 70

Table 6-16. Solvay Secondary PM2.5 Impacts – 24-hour Average ...... 71

iii Table 6-17. Solvay Secondary PM2.5 Impacts – Annual Average ...... 72 Table 6-18. Competing Sources for Inclusion in Full NAAQS Analysis ...... 73 Table 6-19. Class II Significant Impact Areas for ARGO Project ...... 75 Table 6-20. Summary of Maximum Modeled Impacts – NAAQS/WAAQS Analysis ...... 77 Table 6-21. Summary of Maximum Modeled Impacts – PSD Increment Analysis ...... 78 Table 7-1. Class I Areas Located within 300 Kilometers of Solvay ...... 81 Table 7-2. Class I PSD Increments and SILs ...... 82 Table 7-3. Summary of Maximum Modeled Impacts Compared to Class I Area SILs ...... 82 Table 8-1. Comparison of Predicted Project Impacts to Vegetation Damage Threshold ...... 86 Table 9-1. Solvay Ozone Impacts ...... 89 Table 10-1. Toxicity-Weighted Screening for Carcinogenic HAPs ...... 91 Table 10-2. Carcinogenic Inhalation Risk Summary at Maximum Impact Receptor ...... 92

Figures Figure 1-1. Solvay Facility Location on a Regional Scale Map ...... 9 Figure 1-2. Westerly View of the Solvay Facility ...... 10 Figure 2-1. Solvay Facility Plant Layout and Emission Points ...... 13 Figure 6-1. Building and Source Layout at Solvay Facility ...... 57 Figure 6-2. Source Layout at Solvay Facility – Including Mobile Source Locations ...... 58 Figure 6-3. Overview of Receptor Grid Used in the Impact Analysis ...... 63 Figure 6-4. EPA’s PGM Modeling Domain and Hypothetical Source Locations – Western U.S...... 68 Figure 6-5. Map of Locations of Maximum Modeled Impacts from NAAQS and PSD Increment Analyses ...... 79 Figure 7-1. Location of Class I Areas within 300 Kilometers of the Solvay Facility ...... 80

Appendices Appendix A: ARGO Project Process Flow Diagram Appendix B: Emissions for New and Modified Sources Appendix C: Project Emissions Inventory Summaries Appendix D: Contemporaneous Source Emissions Appendix E: Characterization of Mobile Sources and Cooling Towers for Modeling Appendix F: Class I Area FLAG Initial Criteria Screening Analysis Appendix G: Emission Calculations for Health Risk Assessment Appendix H: Best Available Control Technology Review

iv LIST OF ABBREVIATIONS AND ACRONYMS

AMS American Meteorological Society AQRV Air Quality Related Value AQRV Air Quality Related Values BACT Best Available Control Technology BAE Baseline Actual Emissions BLM Bureau of Land Management BPIP Building Profile Input Program CAM Compliance Assurance Monitoring CEMS Continuous Emissions Monitoring System CFR Code of Federal Regulations CO Carbon Monoxide CO2 Carbon Dioxide COMS Continuous Opacity Monitoring System DEM Digital Elevation Model dscf Dry Standard Cubic Foot EA Environmental Assessment EPA United States Environmental Protection Agency ESP Electrostatic Precipitators FLAG Federal Land Managers Air Quality Related Values Workgroup FLM Federal Land Manager ft Feet g Gram GAQM Guideline on Air Quality Models GHG Greenhouse Gas GIS Geographical Information Systems H2S Hydrogen Sulfide H2SO4 Sulfuric Acid Mist HAP Hazardous Air Pollutant HF Hydrogen Fluoride HHV Higher Heating Value hr Hour IUR Inhalation Unit Risk l Liter lb Pound LHV Lower Heating Value m Meter min Minute MACT Maximum Achievable Control Technology MERPs Modeled Emission Rates for Precursors MMBtu Million British Thermal Units MMtpy Million Tons per Year μ Micro (10-6) NAAQS National Ambient Air Quality Standards NED National Elevation Dataset NESHAP National Emission Standards for Hazardous Air Pollutants NG Natural Gas NP National Park NPS National Park Service NRCS National Resources Conservation Service

v NSPS New Source Performance Standards NSR New Source Review N2 Nitrogen NO2 Nitrogen Dioxide NOX Nitrogen Oxides O3 Ozone PAE Projected Actual Emissions PGM Photochemical Grid Modeling PM Particulate Matter PM2.5 Particulate Matter (with aerodynamic diameter ≤ 2.5 micron) PM10 Particulate Matter (with aerodynamic diameter ≤ 10 micron) ppb Parts per Billion ppm Parts per Million PRIME Plume Rise Model Enhancements PSD Prevention of Significant Deterioration PTE Potential to Emit sec Second SER Significant Emission Rate SIA Significant Impact Area SIL Significant Impact Level SIP State Implementation Plan SMU Soil Map Unit Solvay Solvay Soda Ash Joint Venture SO2 Sulfur Dioxide SO4 Sulfate tph Tons per Hour tpy Tons per Year TSP Total Suspended Particles TWSA Toxicity-weighted Screening Analysis U.S. United States USDA United States Department of Agriculture USFS U.S. Forest Service UTM Universal Transverse Mercator VOC Volatile Organic Compound WAAQS Wyoming Ambient Air Quality Standards WAQSR Wyoming Air Quality Standards and Regulations WDEQ Wyoming Department of Environmental Quality yr Year

vi 1.0 INTRODUCTION

Solvay Soda Ash Joint Venture (Solvay) proposes several modifications (referred to as project ARGO) at its Green River, Wyoming facility to increase soda ash production. The ARGO project will consist of an additional production line, while increasing the facility’s total permitted annual production rate from 3.6 million tons per year (MMtpy) soda ash to 4.1 MMtpy soda ash. Additional significant features of the proposed ARGO project will include the conversion of the existing coal-fired “A” and “B” calciners (Source #17) to natural gas (NG) combustion and the conversion of the existing coal-fired boilers (Sources #18 and #19) to NG combustion.

As part of the proposed ARGO production expansion project, Solvay wishes to modify the Green River facility by:

 Installing a new 200 ton per hour (tph) soda ash product dryer (refer to as DR-8, Source #111),

 Installing a new “E” train dryer area baghouse (refer to as Source #110),

 Installing a MVR crystallizer, centrifuges, pumps, and associated piping and making other minor operational and equipment changes to debottleneck productions in other ways,

 Converting the existing coal-fired “A” and “B” calciners (Source #17) to natural gas combustion, and increasing the permitted throughput from 160 tph to 200 tph for each calciner (total of 400 tph for Source #17, the previously permitted rate when the calciners were NG fired),

 Converting the existing coal-fired boilers (Sources #18 and #19) to NG combustion, and

 Increasing the permitted throughput for the existing DR-6 product dryer (Source #82) from 161 tph soda ash to 200 tph soda ash.

The proposed soda ash expansion will be constructed adjacent to the existing facility on previously disturbed private lands. This expansion is similar to a previous Solvay production expansion project in 1997 that involved the installation of a new calciner and DR-6. All sources will be permitted to operate continuously (8,760 hours per year) at their maximum design rates. Solvay plans to begin construction of the ARGO expansion project in 2020.

As a result of these proposed changes, several sources at the facility will be debottlenecked, allowing an increase in annual production at the facility. Aside from the project modifications listed above, none of the short-term (hourly and 24-hour) existing process source capacities will change with these modifications. The combination of changes will serve to increase both short-term and long-term production while remaining within the previously permitted capacity rates and within both short-term and long-term potential-to-emit (PTE) limits.

7 The sum of the emissions changes from the new sources, the existing modified sources, the associated debottlenecked sources, and creditable contemporaneous emissions increases result in a significant net emissions increase of particulate matter (PM, PM10, and PM2.5), carbon monoxide (CO), volatile organic compounds (VOC), and greenhouse gases (GHG), thus triggering Prevention of Significant Deterioration (PSD) review.

In November 2013, the Wyoming Department of Environmental Quality (WDEQ) issued an air permit (MD-13083) for a major modification (Prevention of Significant Deterioration [PSD]) at the Green River facility to allow for the installation of one 254 million British thermal units (MMBtu)/hour (hr) NG-fired package boiler (BO-4, Source #109) to provide steam and heat to the facility’s production processes and for other purposes, such as building heat. With the BO-4 project, several existing sources at the facility were debottlenecked, allowing an increase in annual production at the facility. Several of the technical approaches to be utilized for the ARGO air permit application (e.g., emissions inventory and PSD applicability, approach to contemporaneous emissions, overall dispersion modeling approach, etc.) are similar to the WDEQ-approved analyses from the BO-4 PSD permit application in 2013.

This report provides a review and technical analysis of the various requirements triggered by PSD rules as part of an application for permit modification. This technical analysis consists of a facility and project description (Section 2.0), followed by a PSD applicability analysis (Section 3.0), a regulatory applicability review (Section 4.0), a Best Available Control Technology (BACT) review (Section 5.0), and air quality impact analyses for both Class II and Class I areas (Sections 6.0 and 7.0). In addition, a PSD additional impacts analysis for growth, soil and vegetation impacts is provided in Section 8.0, an ozone analysis is provided in Section 9.0, and an inhalation risk assessment for hazardous air pollutants (HAPs) is provided in Section 10.0.

The Solvay facility is located in Section 31, T18N, R109W, approximately 20 miles west of the town of Green River, in Sweetwater County, Wyoming. The Universal Transverse Mercator (UTM) location is 603.7 km Easting and 4594.8 km Northing (North American Datum 1927, Zone 12). The geographic coordinates are 41.502 N degrees latitude and 109.757 W degrees longitude. The facility location on a regional scale map is shown in Figure 1-1; a westerly view of the facility is shown on Figure 1-2.

8 Figure 1-1. Solvay Facility Location on a Regional Scale Map

9 Figure 1-2. Westerly View of the Solvay Facility

10 2.0 FACILITY AND PROJECT DESCRIPTION

The Solvay facility is an existing underground trona mine with surface processing facilities. The trona ore

(sodium sesquicarbonate dihydrate [Na2CO3·NaHCO3·2H2O]) is processed into sodium-based products, including soda ash (sodium carbonate [Na2CO3]), Alkaten (animal feed), T-200 (air pollution control), sodium sulfite, and sodium bicarbonate. Construction of the facility began in 1979, and it became operational in 1982. Operations at the facility include the use of crushers, screeners, rotary calciners, rotary dyers, separation and recrystallization equipment, enclosed bulk storage, product loading/material handling equipment, boilers, and coal handling facilities. The air emission sources consist principally of calciners, dryers, boilers, and material handling processes. The facility is presently permitted under WDEQ Operating Permit No. 3-0-126 (effective January 13, 2013).

Currently, the Solvay plant cannot reach its capacity soda ash production. The proposed facility changes will allow several other emission units at the facility to operate at higher rates and more hours each year (i.e., these sources will be debottlenecked), resulting in actual increases in annual production at the facility. None of the debottlenecked emission units will operate above currently permitted capacities. Solvay anticipates the debottlenecking to increase soda ash production by approximately 500,000 tons per year (tpy) from the current actual production level of 2.54 million tons (5-year production average from 2013 to 2017) to 3.04 million tons of soda ash. The facility’s total permitted annual production rate capacity will increase from 3.6 million tons per year soda ash to 4.1 million tons per year soda ash.

The existing debottlenecked emission units will be capable of accommodating the anticipated increases in annual production. In other words, the debottlenecking of the existing emission units will not result in any short- or long-term PTE emissions increases, but it will allow the facility to produce more product and operate more hours each year, resulting in annual actual emissions increases. The details on emissions increases associated with the project are provided in Section 3.0.

Table 2-1 provides a listing of the “project” sources (i.e., new sources #111 and #110; existing modified sources #17, #18, and #19; and the associated existing debottlenecked sources). A process flow diagram showing the ARGO project sources is provided in Appendix A.

Solvay has identified 22 existing sources that will be debottlenecked as a result of the installation of the ARGO project. This debottlenecked sources roster is identical to the debottlenecked sources list from the BO-4 PSD project in 2013. Of these sources, 15 are material handling sources with particulate emissions controlled by baghouses. Five are existing combustion sources with emissions controlled by electrostatic precipitators (ESPs). The combustion sources include calciners A through D, and two dryers; WDEQ considers the coal-fired calciners A and B as one source (Source #17). Source #15 (Dryers #1 and #2) is a steam tube dryer only and does not have its own burner. Solvay has a small NG preheater installed on Dryers #1 and #2, but this preheater has not been used for several years. Solvay no longer wishes to use the Source #15 preheaters and wishes to eliminate them from the facility’s air permit. As a result, Source #15 is not considered a combustion source here.

11 Table 2-1. List of ARGO Project Sources: New, Modified, and Debottlenecked Sources

WDEQ Combustion Source Source Description Type Source? Fuel(s) ID 111 DR-8 Product Dryer New Combustion Yes Gas 110 “E” Train Dryer Area Baghouse New Baghouse No --- Modified Existing Combustion, 18 #1 Boiler (converted to NG) Yes Gas ESP Modified Existing Combustion, 19 #2 Boiler (converted to NG) Yes Gas ESP 02A Ore Crusher Building #1 Existing Baghouse No --- 06A Product Silos -Top Existing Baghouse No --- 06B Product Silos - Bottom #1 Existing Baghouse No --- 7 Product Loadout Station Existing Baghouse No --- 15 DR-1 & 2 Steam Tube Dryers Existing Combustion, Scrubber No* None 16 Dryer Area Existing Baghouse No --- Modified Existing Combustion, 17 "A" and "B" Calciners (converted to NG) Yes Gas ESP 46 Ore Transfer Station Existing Baghouse No --- 48 "C" Calciner Existing Combustion, ESP Yes Gas 50 "C" Train Dryer Area Existing Baghouse No --- 51 Product Dryer #5 Existing Combustion, ESP Yes Gas 52 Product Silo - Top #2 Existing Baghouse No --- 53 Product Silo - Bottom #2 Existing Baghouse No --- 76 "D" Train Primary Ore Screening Existing Baghouse No --- 79 Ore Transfer Point Existing Baghouse No --- 80 "D" Ore Calciner Existing Combustion, ESP Yes Gas 81 "D" Train Dryer Area Existing Baghouse No --- 82 DR-6 Product Dryer Existing Combustion, ESP Yes Gas 99 Crusher Baghouse #2 Existing Baghouse No --- 103 East Ore Reclaim Baghouse Existing Baghouse No --- 104 West Ore Reclaim Baghouse Existing Baghouse No --- 109 NG-fired Package Boiler Existing Combustion Yes Gas * Source #15 fed by heat from boilers only, old preheaters on Source #15 are no longer used so there are no actual gaseous emissions.

The plant layout with the various buildings and all the facility emission points is shown on Figure 2-1.

12 Figure 2-1. Solvay Facility Plant Layout and Emission Points

13 3.0 PSD APPLICABILITY ANALYSIS

According to WDEQ Operating Permit No. 3-1-126, the Solvay facility has the PTEs of 486 tpy of PM and

PM10; 3,031 tpy of NOx; 14,825 tpy of CO; 619 tpy of SO2; 6,827 tpy of VOC; and 466 tpy of HAPs. In addition, the facility is a major source for PM2.5 and greenhouse gases (GHG). Thus, the Solvay Green River facility is an existing major stationary source under the New Source Review (NSR) PSD permitting program because it has the potential to emit greater than 250 tpy of several criteria pollutants including

PM, PM10, PM2.5, NOX, CO, SO2, VOC, and GHG. A project proposed at an existing major stationary source is subject to PSD review if the project is either a major modification to an existing major stationary source, or a major stationary source unto itself (meaning emissions from the project itself exceeds 250 tpy for a particular PSD pollutant).

For purposes of determining whether a project qualifies as a “major modification,” thus triggering PSD review, Wyoming Air Quality Standards and Regulations (WAQSR), Chapter 6, Section 4(b)(i)(J)(I), indicates that a project is a major modification for a regulated NSR pollutant if it causes two types of emissions increases – a “Significant emissions increase” (as defined in WAQSR, Chapter 6, Section 4(a)), and a “Significant net emissions increase” (as defined in the definitions for “Net emissions increase” and “Significant” in Section 4(a)). The project is not a major modification subject to NSR review if it does not cause a significant emissions increase. If the project causes a significant emissions increase, then the project is a major modification only if it also results in a significant net emissions increase. Significant emissions increase means that the emissions increase for any regulated NSR pollutant is greater than the NSR Significant Emission Rate (SER) threshold for that regulated pollutant (see WAQSR, Chapter 6, Section 4(a) definition of “significant”).

3.1 Net Emissions Increase from Project Based on WAQSR, Chapter 6, Section 4(b)(i)(J)(II), the procedure for calculating whether a significant emissions increase will occur at a major stationary source depends on the units being modified. For new emissions units at the facility (i.e., #110 and #111), the increase in emissions is equal to the PTE of the unit and the baseline actual emissions (BAE) for the new source is zero. For existing emissions units (e.g., Solvay’s debottlenecked sources), the increase in emissions is typically calculated as the difference between the projected actual emissions (PAE) and the BAE.

BAE are defined in WAQSR, Chapter 6, Section 4(a) for an existing emissions unit (other than an electric utility steam generating unit). BAE means the average rate, in tons per year, at which the emissions unit actually emitted the pollutant during any consecutive 24-month period selected by the owner or operator within the 10-year period immediately preceding either the date the owner or operator begins actual construction of the project, or the date a complete permit PSD application is received by WDEQ, whichever is earlier. For a regulated NSR pollutant, when a project involves multiple emissions units, only one consecutive 24-month period must be used to determine the BAE for the emissions units being changed. A different consecutive 24-month period can be used for each regulated NSR pollutant.

14 PAE are defined in WAQSR, Chapter 6, Section 4(a) for both new and existing units and means the maximum annual rate, in tpy, at which an existing emissions unit is projected to emit a regulated NSR pollutant in any one of the 5 years (12-month period) following the date the unit resumes regular operation after the project. In lieu of calculating PAE, the emissions for a unit may be calculated as the PTE for the unit.

Note that the PTE emissions calculation details and source release characteristics for the new and modified project sources are provided in Appendix B. The details regarding the PAE and BAE emission calculations for the ARGO project sources are provided in Appendix C. To calculate BAE for the existing project sources, Solvay utilized the baseline years of 2016–2017 from facility-wide actual emissions information, which is provided to WDEQ annually.

To determine the PAE from the existing project debottlenecked sources, Solvay assumed the following:

 There are no short-term (1-hour and 24-hour) increases in PTE for these sources.

 There is no need to physically modify existing debottlenecked source equipment, which can already accommodate anticipated production increases from debottlenecking.

 For baghouses already operating 8,760 hours per year (e.g., #02A, #06A, #46, #99, #103, #104), there will be no annual emissions increases.

 For baghouses (and Source #15) currently operating less than 8,760 hours per year, and for the combustion sources, the projected actual emissions are estimated by scaling the annual operations/emissions by the proposed ARGO product increase of 63% (i.e., the baseline soda ash production rate of 2.52 MMtpy scaled up to the new proposed soda ash production limit of 4.1 MMtpy), not to exceed the current PTE emission limits.

As shown in Table 3-1, a summary of the net emissions increases from the proposed ARGO project compared to the PSD significant emission rates. The project net emissions exceed the significant emission rates for PM, PM10, PM2.5, CO, VOC, and GHG, and trigger PSD review. NOx, SO2, lead, fluorides, hydrogen sulfide (H2S), and sulfuric acid mist (H2SO4) emissions from the project are not significant and these pollutants are not considered further since they do not trigger PSD. For the pollutants that do not trigger PSD (NOx, SO2, lead), PTE emissions were used in lieu of PAE emissions to demonstrate that the project does not trigger PSD for these pollutants using either PAE or PTE emissions.

From Table 3-1, estimated increases in lead emissions from the project (0.0056 tpy) are well below the corresponding significant emission rate of 0.6 tpy. Solvay has performed analytical testing on its feedstock ore and soda ash product and lead has not been detected in either (i.e., tests were below detection limits). Thus, there are no process emissions of lead at the facility. Lead is potentially emitted in trace quantities from the combustion sources as part of the ARGO project (#111, #17, #18, #19, #48, #51, #80, #82, and #109).

Estimated increases in fluoride emissions (as hydrogen fluoride) are insignificant since there will be not coal combustion sources associated with the ARGO project. There is no fluoride in Solvay’s feedstock ore

15 and soda ash product since the geographical formation around the facility is not favorable for fluorides. Thus, there are no process emissions of fluorides at the facility. Fluorine is a trace element in natural gas and when these fuels are burned, fluorine may be emitted as hydrogen fluoride [HF], but emissions from gas-combustion are not considered significant (e.g., there are no AP-42 emission factors for fluorine or HF).

There are a few small existing emission sources of H2S and H2SO4 emissions at the facility, but these sources are not affected by the proposed ARGO project. Thus, emissions of H2S and H2SO4 will not increase as a result of the proposed ARGO project and no further analysis is considered for these pollutants; these pollutants do not trigger PSD review.

16 Table 3-1. Emissions Increases from ARGO Project

Emissions (tpy)

Description PM* NOX CO VOC SO2 CO2e Baseline Actual Emissions of Debottlenecked Sources (2016–2017) 203 1,275 4,940 1,212 48 1,314,384

Projected Actual Emissions of Debottlenecked Sources ** 147 252 5,884 537 1 1,060,384 Potential Emissions of New and Modified Sources 159 407 9,519 3,006 3 1,302,932 Contemporaneous Increases and Decreases 0.9 N/A N/A N/A N/A N/A Post-Modification Subtotal 306 660 15,403 3,543 4 2,363,316

Net Change in Emissions 103 -615 10,463 2,331 -44 1,048,932

PSD Significant Thresholds 10 40 100 40 40 75,000

PSD Triggered Yes No Yes Yes No Yes

* Assumes PM=PM10=PM2.5

** The projected actual emissions for the debottlenecked sources of NOx and SO2 are represented by potential emissions.

17 3.2 Contemporaneous Sources For all pollutants that will have a projected emissions increase exceeding the SER (see Table 3-1), a further analysis was used to determine the creditable emissions increases and decreases that occurred during the contemporaneous period for purposes of determining the “net emissions increase” of that pollutant associated with the project. From Table 3-1, emissions of PM, PM10, PM2.5, CO, VOCs, and GHG exceed the SER. Emissions of NOx, SO2, and lead are not significant and no further analysis is required; PSD does not apply to these pollutants. “Net emissions increase” is defined in WAQSR, Chapter 6, Section 4(a). In general, the net emission increase considers the significant emissions increases from the project and any other increases and decreases in actual emissions at the major stationary source that are contemporaneous with the particular change and are otherwise creditable.

In general, an increase or decrease in actual emissions is contemporaneous with the increase from the particular change only if it occurs between the date five years before construction on the particular change commences and the date that the increase from the particular change occurs. In addition, an increase or decrease in actual emissions is creditable only if WDEQ has not relied on it in issuing a previous PSD permit for the source, which is in effect when the increase in actual emissions from the particular change occurs.

Assuming that the proposed ARGO project were to begin construction in 2020, the contemporaneous period would be defined as the period from 2015 (five years before construction) to the date when the proposed project becomes operational. As provided in detail in Appendix D: all Solvay permitting actions from 2015 to present have been listed along with the facility sources affected by the permitting action. For those emissions that are creditable, the net emissions changes have been determined following WDEQ’s definition of net emissions increase for contemporaneous sources. There have been nine permitting actions at the facility since 2015, not including this proposed ARGO permit action. These actions are listed on Page 1 of Appendix D.

Solvay has analyzed these permitting actions and contends that emissions associated with six of these actions are not creditable (see Page 2, Appendix D). As discussed with WDEQ at a February 23, 2012 meeting for the previous BO-4 PSD project, emissions sources that were both introduced to and then removed from the facility during the contemporaneous period are not considered creditable. In addition, temporary projects and projects with no emissions changes or insignificant emissions changes are not considered creditable.

Creditable emissions increases at existing sources (i.e., sources in existence prior to the contemporaneous period) are provided in detail on Page 3 of Appendix D. Creditable emissions increases at new sources (i.e., those sources permitted for the first time during the contemporaneous period) are provided in detail on Page 4 of Appendix D.

From the ARGO project contemporaneous source analysis (Pages 3 and 4 of Appendix D), there are only three creditable contemporaneous permit actions related to the ARGO project at the Solvay facility:

18  Waiver P0020929 on 06/21/2016 (PM increases for sources #6A, #6B, #7, #52, #53, #81, #82 and no emissions changes or emissions decreases for several other PM sources)

 Waiver P0022664 on 03/15/2017 (Longwall Water Evaporator Vent)

 Permit No. P0023144 on 06/12/2017 (MikroPul 25S-10-20 Baghouse [source CH010])

For Waiver P0020929, the sources with PM increases are a subset of the same sources as the debottlenecked ARGO project sources. Thus, the ARGO project debottlenecked sources list is utilized as the main source list to define project emissions for these sources (and to avoid double-counting for these sources); sources from Waiver P0020929 are already included on the ARGO project list. The Longwall Water Evaporator Vent is an insignificant source of emissions. Thus, the ARGO project contemporaneous source that is creditable and counted in the project’s net emission increase calculations is the MikroPul 25S-10-20 Baghouse (source CH010).

A summary of the emissions inventory for the ARGO project is provided in Appendix C.

Please note that as part of the ARGO project, Solvay wishes to remove the following sources from the facility: coal-related sources (#10, #11, #14, #24, #67, #100, and the coal road) and other sources (temporary pony boiler [PB], DECA storage and the DECA road, GND, GNS1, GNS2, #107, and #108).

19 4.0 AREA DESIGNATION AND APPLICABLE AIR POLLUTION CONTROL REQUIREMENTS

The facility is presently permitted under WDEQ Operating Permit No. 3-1-126 (effective January 17, 2013). This permit incorporates applicable requirements for the existing sources at the facility. Thus, the New Source Performance Standards (NSPS), National Emission Standards for Hazardous Air Pollutants (NESHAPs), and WDEQ Air Quality Division Standards and Regulations (WAQSR) applicability determinations below focus on the new and existing modified sources for the Solvay ARGO project only; they do not address the other existing sources at the facility.

4.1 Federal Regulations 4.1.1 Calciners With the ARGO project, Source #17 (i.e., the "A" and "B" Calciners) will be converted from coal to natural gas (NG), and the throughput for each will be increased from 160 to 200 tph. These calciners are not subject to any NSPS under 40 Code of Federal Regulations (CFR) 601. In addition, these calciners are not subject to any NESHAP under 40 CFR 63. Furthermore, the proposed changes do not constitute reconstruction as defined in §63.2, §63.41, and WAQSR Chapter 6, Section 6(f)(xii).

4.1.2 Natural Gas-Fired Boilers As part of the ARGO project, Sources #18 and #19, that is, #1 and #2 Boilers, will be converted from coal to NG. These boilers have a rated heat input of 387 MMBtu/hr, higher heating value (HHV) (350 MMBtu/hr, lower heating value [LHV]). The conversion to NG does not constitute reconstruction as defined in §60.15(b) and WAQSR, Chapter 5, Section 2(l)(ii). These boilers are currently subject to 40 CFR 60, Subpart D - Standards of Performance for Fossil-Fuel-Fired Steam Generators (NSPS, Subpart D), and will remain subject to such with the conversion to NG. In accordance with WAQSR, Chapter 5, Section 2(b), WDEQ has incorporated by reference NSPS, Subpart D.

Solvay is an existing major source of HAPs (estimated at 466 tpy); that is a facility or has the potential to emit at least 10 tpy of any individual HAP or 25 tpy of combined HAPs. Since Sources #18 and #19 are located at a major source of HAPs, they will remain subject to 40 CFR 63, Subpart DDDDD—National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters (NESHAP, Subpart 5D). The conversion to NG does not constitute reconstruction as defined in §63.2 and incorporated by reference in WAQSR Chapter 5, Section 3(d). In accordance with WAQSR, Chapter 5, Section 3(b), WDEQ has incorporated by reference NESHAP, Subpart 5D.

1 NSPS, Subpart UUU addresses Standards of Performance for Calciners and Dryers in Mineral Industries, however the “A” and “B” Calciners do not process or produce any of the materials listed under the definition of mineral processing plant (§60.731), and therefore, NSPS, Subpart UUU does not apply.

20 4.1.2.1 NSPS, Subpart D - Standards of Performance for Fossil Fuel-Fired Steam Generators 40 CFR 60.40(a)(1) defines the affected facilities subject to NSPS, Subpart D to be each fossil fuel-fired, steam generating unit that has a heat input capacity greater than 250 MMBtu/hr. In accordance with §60.40(c), any facility under paragraph (a) of this section that commenced construction after August 17, 1971, is subject to the requirements of this subpart. Sources #18 and #19 are fossil fuel-fired, steam generating units with a heat input capacity greater than 250 MMBtu/hr, and will remain subject to NSPS, Subpart D with the conversion to NG - also, a fossil fuel. Since the conversion to NG does not constitute a modification per §60.14(a)2 and/or §60.14(e)(4), or reconstruction, these boilers are not subject to the newer standard, 40 CFR 60 Subpart Db - Standards of Performance for Industrial-Commercial-Institutional Steam Generating Units.

Per §60.42(d), an owner or operator of an affected facility that combusts only NG is exempt from the PM and opacity standards specified in §60.42(a). In addition, there are no applicable SO2 standards in NSPS, Subpart D for NG-fired boilers. Therefore, Sources #18 and #19 will not be not subject to any NSPS PM, opacity, or SO2 standards. As a result, Solvay is proposing to remove the existing ESP controls, SO2 scrubber controls, SO2 continuous emissions monitoring system (CEMS), and continuous opacity monitoring systems (COMS) on Sources #18 and #19.

Since Sources #18 and #19 will combust NG, per §60.44(a)(1), these sources will not be allowed to discharge into the atmosphere any gases that contain NOX, expressed as NO2, in excess of 0.20 lb/MMBtu. Solvay will continue to operate the NOx CEMS installed on Sources #18 and #19.

4.1.2.2 NESHAP, Subpart DDDDD – Industrial, Commercial, and Institutional Boilers and Process Heaters 40 CFR 63.7575 defines an industrial boiler as a boiler used in manufacturing, processing, mining, and refining or any other industry to provide steam, hot water, and/or electricity. In accordance with §63.7485, a facility is subject to NESHAP, Subpart 5D if they own or operate an industrial boiler as defined in §63.7575 that is located at, or is part of, a major source of HAPs. Sources #18 and #19 are currently subject to NESHAP, Subpart 5D as existing industrial boilers, and will remain subject to such with the conversion to NG. As discussed above, the conversion to NG does not constitute reconstruction.

Per §63.7499 and §63.7575, Sources #18 and #19 will be defined by the subcategory: units designed to burn gas 1 fuels (e.g., NG). Per §63.7500(a)(1), §63.7500(e), and Table 3 to Subpart 5D, existing industrial boilers in the “units designed to burn gas 1 fuels” subcategory are subject to work practice standards that require periodic tune-ups, in lieu of emission limits.

2 The proposed conversion to NG will not result in an increase in the emission rates of PM, SO2, or NOX.

21 4.1.3 Soda Ash Product Crushing, Screening, and Transfers As part of the ARGO project, Solvay will add Source #110, that is, the “E” Train Dryer Area, which includes crushing, screening, and material transfers of the soda ash dried in Source #111, the proposed DR-8 Product Dryer. These activities generate particulate emissions and are subject to 40 CFR 60, Subpart OOO - Standards of Performance for Nonmetallic Mineral Processing Plants (NSPS, Subpart OOO). In accordance with WAQSR, Chapter 5, Section 2(b), WDEQ has incorporated by reference NSPS, Subpart OOO.

The “E” Train Dryer Area is not subject to any NESHAP under 40 CFR 63.

4.1.3.1 NSPS, Subpart OOO - Standards of Performance for Nonmetallic Mineral Processing Plants 40 CFR 60.670(a)(1) designates the affected facilities at a fixed nonmetallic mineral processing plant to include: each crusher, grinding mill, screening operation, bucket elevator, belt conveyor, bagging operation, storage bin, enclosed truck, or railcar loading station. In accordance with §60.670(e), an affected facility under paragraph (a) of this section that commences construction, after August 31, 1983, is subject to the requirements of this part. Since the crushing, screening, and material transfers at the “E” Train Dryer Area will be processing soda ash (a nonmetallic mineral), Source #110 will be subject to NSPS, Subpart OOO.

Solvay is proposing to install a baghouse to control the activities included in Source #110; discussed further in the BACT Review (see Section 5.0 and 10.0Appendix H: Appendix H: ). Per §60.672(a), affected facilities with capture systems must meet the stack emission limits in Table 2 of Subpart OOO. Since the “E” Train Dryer Area affected facilities will commence construction after April 22, 2008, the Source #110 baghouse will be subject to the stack emission limit for PM of 0.014 gr/ dry standard cubic foot (dscf).

Per §60.672(b), fugitive emission escaping a capture system must meet the limits in Table 3 of Subpart OOO. Since the “E” Train Dryer Area affected facilities will commence construction after April 22, 2008, the Source #110 baghouse will be subject to the fugitive emission limit of 7 percent opacity.

4.1.4 Product Dryer With the ARGO project, Source #111, the DR-8 Product Dryer, will be added to the process. This dryer will have a rated heat input of 200 MMBtu/hr and will combust NG. This dryer is not subject to any NSPS under 40 CFR 60 nor any NESHAP under 40 CFR 63.3

3 NESHAP, Subpart 5D addresses standards for Industrial, Commercial, and Institutional Boilers and Process Heaters, however, the DR-8 Product Dryer does not meet the definition of process heater, which specifies devices in which combustion gases do not come into direct contact with the process materials (§63.7575), and therefore, NESHAP, Subpart 5D does not apply.

22 4.2 Wyoming Department of Environmental Quality Air Quality Division Standards and Regulations The following WAQSR are applicable to the new and modified sources for the ARGO project.

4.2.1 Chapter 5: National Emission Standards WAQSR, Chapter 5, Section 2. New source performance standards. Section 2(b): The following applicable NSPS are incorporated by reference under Section 4(a) of Chapter 5:

 40 CFR Part 60, Subpart D - Standards of Performance for Fossil Fuel-Fired Steam Generators (applicable to Sources #18 and #19)

 40 CFR Part 60, Subpart OOO - Standards of Performance for Nonmetallic Mineral Processing Plants (applicable to Source #110)

WAQSR, Chapter 5, Section 3. National emission standards for hazardous air pollutants. Section 3(b): The following applicable NESHAP are incorporated by reference under Section 4(a) of Chapter 5:

 40 CFR Part 63, Subpart DDDDD - National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters (applicable to Sources #18 and #19)

4.2.2 Chapter 6: Permitting Requirements WAQSR, Chapter 6, Section 2. Permit requirements for construction, modification, and operation. Section 2(a)(i): Solvay proposes to modify an existing facility, which may cause an increase in air contaminants. Thus, Solvay must obtain a construction permit.

Section 2(b)(i): The application includes plans, specifications, and the manner in which the sources are to be operated and controlled.

Baseline ambient monitoring may be required at the discretion of the Administrator. This proposed modification may result in a significant net emissions increase of criteria pollutants including PM10, PM2.5, CO, and VOC. Solvay previously monitored for total suspended particulates (TSP), and is currently monitoring for PM10. The on-site PM10 monitor has shown no exceedance of the Wyoming PM10 24-hour or annual standards. Additional regional monitoring has been conducted for CO at the Yellowstone

National Park and Tata monitoring stations, and for PM2.5 in Rock Springs. Solvay believes sufficient monitoring has been conducted to define a representative baseline for this application. The ambient baseline information representative of the facility location is provided in Section 6.5.4.

23 Section 2(c)(ii): The application must demonstrate compliance with the Wyoming Ambient Air Quality Standards (WAAQS), as shown in Section 6.0 of this application.

Section 2(c)(iii): The application must demonstrate compliance with PSD increments, as shown in Section 6.0 of this application.

Section 2(c)(v): The sources must utilize the Best Available Control Technology (BACT). A BACT analysis for criteria pollutants is found in Section 5.0 (and Appendix H: ) of this application.

Section 2(c)(vi): The facility must have provisions for measuring the emissions of significant air contaminants as determined by the Administrator. These are already in place for the existing sources at the facility, as described in the current Operating Permit No. 3-1-126, and will be added for the new or modified sources.

WAQSR, Chapter 6, Section 3. Operating Permits: Solvay is subject to these requirements and will submit a separate application for that purpose within 12 months after the new source commences operation, as required.

WAQSR, Chapter 6, Section 4. Prevention of significant deterioration. Section 4(b)(i)(J)(I)): For purposes of determining whether a project qualifies as a major modification, thus triggering PSD review, this regulation requires a determination of two types of emissions increases - a “Significant emissions increase” [as defined in WAQSR, Chapter 6, Section 4(a)], and a “Significant net emissions increase” [as defined in the definitions for “Net emissions increase” and “Significant” in Section 4(a)]. As discussed in more detail in Section 3.0 of this report, the following pollutants have net emissions increases as a result of the proposed ARGO project and PSD review following WAQSR,

Chapter 6, Section 4 procedures is triggered for: PM, PM10, PM2.5, CO, VOC, and GHG.

WAQSR, Chapter 6, Section 6. Permit requirements for case-by-case maximum achievable control technology (MACT) determination: These requirements do not apply as the proposed changes do not constitute construction or reconstruction of a major source of HAPs [as defined in WAQSR, Chapter 6, Section 6(f)].

4.2.3 Chapter 7: Monitoring Regulations WAQSR, Chapter 7, Section 3, Compliance assurance monitoring (CAM): CAM applies to any pollutant-specific emission unit at a major source that is required to obtain a Title V permit, if it meets all of the following criteria [per WAQSR, Chapter 7, Section 3(b)]:

 The unit is subject to an emission limit or standard for an applicable regulated air pollutant.

 The unit uses a control device to achieve compliance with the applicable emission limit or standard.

24  The unit has potential pre-control device emissions of the applicable regulated air pollutant of at least 100 percent of the amount, in tpy, required for the sources to be classified as a major source.

4.2.3.1 Source #17: “A” and “B” Calciners Source #17 is currently subject to CAM for ESP control of PM and no changes to the existing CAM plan, other than descriptive changes to the background information of the CAM plan, consistent with the information in the ARGO permit application (e.g., modified emission rate for PM), are requested.

4.2.3.2 Sources #18 and #19: #1 and #2 Boilers With the conversion to NG, Sources #18 and #19 are no longer subject to CAM for ESP control of PM.

Based on NG combustion, the potential pre-control device PM, PM10, and PM2.5 emissions are less than 100 tpy, and therefore Solvay is proposing to remove the existing ESP controls on Sources #18 and #19.

4.2.3.3 Source #110: “E” Train Dryer Area Source #110 will be subject to CAM for fabric filter (i.e., baghouse) control of PM. Per WAQSR, Chapter 7, Section 3(e)(ii), Solvay will submit a CAM Plan for the Source #110 baghouse as part of the application for the first renewal of the Chapter 6, Section 3 Operating Permit addressing Source #110.

4.2.3.4 Source #111: DR-8 Product Dryer Source #111 will be subject to CAM for ESP control of PM. Solvay will submit a CAM Plan for the Source #111 ESP as part of the application for the first renewal of the Chapter 6, Section 3 Operating Permit addressing Source #111.

25 5.0 PROPOSED CONTROLS – BACT

Pursuant to WAQSR, Chapter 6, Section 2(c)(v), Solvay is to provide a BACT analysis for its proposed boiler project for pollutants that have a net emissions increase. As discussed in Section 3.0 of this report, the ARGO project results in a net emissions increase and triggers PSD, including BACT review, for PM,

PM10, PM2.5, CO, VOC, and GHG.

The BACT analysis has been prepared in a separate document and a copy of the BACT report is provided in Appendix H.

26 6.0 AIR QUALITY IMPACT EVALUATION – CLASS II AREAS

The PSD requirements provide for a system of area classifications that affords states an opportunity to identify local land use goals. Each classification differs in terms of the amount of growth it will permit, before significant air quality deterioration would be deemed to occur. There are three area classifications:

 A Class I Area designation involves those areas where almost no change from current air quality is allowed. These areas include wilderness and nationally protected pristine areas.

 A Class II Area designation indicates areas where moderate change is allowed and can accommodate normal well-managed industrial growth, but where air quality constraints are nevertheless desired.

 A Class III Area designation indicates areas where substantial industrial or other growth is allowed and where increases in concentrations up to the national standards would be insignificant. There are no Class III areas in the United States.

The Class I and II areas are subject to different limitations on the allowable increases in ambient concentrations (called increments). Many Class I areas also include additional analyses, and thus employ different numerical approaches not normally considered for the Class II Area. Thus, Class I and Class II impacts are considered separately. This section describes the Class II Area impact analysis. The Class I Area impact analysis is described in Section 7.0.

This section summarizes the applicable ambient air quality standards (Section 6.1), the modeling methodologies used to determine potential air quality impacts (Sections 6.2 through Section 6.6), and the results of the impact analyses from Solvay’s proposed ARGO project (Section 6.7) at Class II areas around the Solvay facility. As summarized in Section 6.7, the maximum modeled impacts from the facility show that Solvay will comply with the National Ambient Air Quality Standards (NAAQS)/WAAQS and PSD increments at all Class II areas. The methodology for this impact analysis is based on Solvay’s impact modeling protocol (dated April 4, 2019; and approved by WDEQ on April 30, 2019).

The proposed ARGO project results in a significant net emissions increase in PM10, PM2.5, CO, and VOC emissions, as described in Section 3.0 of this report. As required by the Wyoming permitting rules, the impacts of these pollutants must be estimated for the areas surrounding the facility, which are Class II areas. PM10, PM2.5, and CO impacts are estimated using the AERMOD (AMS [American Meteorological Society]/EPA [Environmental Protection Agency] Regulatory Model) dispersion model and three years (2009 to 2011) of meteorological data measured onsite at the Solvay facility. As discussed with WDEQ on

February 28, 2019, emissions of NOx, SO2, lead, and fluorides did not exceed their respective SERs and thus are insignificant and are not required to be evaluated in the impact analyses.

27 6.1 Ambient Air Quality Standards Table 6-1 shows the applicable Wyoming Class II standards, PSD increments, and significant impact level

(SIL) for each modeled pollutant. For PM10, PM2.5, and CO, an air quality dispersion analysis was conducted to demonstrate compliance with the applicable standard and increment. Unlike the other pollutants, VOCs do not have an applicable standard but are evaluated as ozone precursors. Thus, a separate analysis for VOC emissions and related ozone impacts are discussed in Section 9.0.

Table 6-1. Applicable Class II Ambient Air Quality Standards, Increments, and SILs

Class II PSD Ambient Standard Increment Class II SIL Criteria Pollutant Averaging Time g/m3 (ppm) (g/m3) a (g/m3)

PM10 24-hour 150 a 30 5 Annual 50 17 1 PM2.5 24-hour 35b 9 1.2 Annual 12 4 0.3 CO 1-hour 40,000 (35) a NA 2,000 8-hour 10,000 (9) a 500 a Not to exceed more than once per year. b 98th percentile 24-hour average concentration.

6.2 General Modeling Approach The PSD modeling analysis involves two phases: a preliminary analysis (referred to as a significant impact analysis) and, if necessary, a full impact analysis. The preliminary analysis estimates ambient concentrations resulting from the proposed project for pollutants that trigger PSD requirements.

The results of the preliminary analysis determine whether a full impact analysis (facility plus competing regional sources) for a particular pollutant is necessary. If the ambient impacts from the preliminary analysis are greater than the SIL (see Table 6-1), then the extent of the significant impact area (SIA) of the proposed project is to be determined and full modeling for the NAAQS and PSD increments is performed as necessary.

The emissions, source characterizations, and modeling methodologies utilized for these analyses are provided in Sections 6.3 through 6.6.

28 6.3 Emission Characterization for Modeling Table 6-2 shows all the Solvay sources (modeled or not), whether existing or new and contemporaneous or debottlenecked, which runs they were included in SIA, or full/competing source runs, and, if not included in any modeling run, the reason for the exclusion.

Throughout the impact analysis, Solvay has assumed that the emergency sources operate no more than 500 hours per year and 4 hours per day during normal facility operations (e.g., no power outage).

Per Solvay’s previous communications with WDEQ regarding the BO-4 PSD project, fugitive sources of particulate emissions (both PM2.5 and PM10) for near-field short-term modeling (24-hour average) were excluded from all SIL, increment, and NAAQS/WAAQS modeling analyses per WDEQ policy.

29 Table 6-2. Solvay Source List, with Annual Operation, Type, Model Run Status

Annual WDEQ Operation In Source ID Source Description (hr/yr) Type* SIA? In Full? 111 DR-8 Product Dryer 8,760 New Yes Yes 110 “E” Train Dryer Area Baghouse 8,760 New Yes Yes 18 #1 Coal-Fired Boiler (converted to NG) 8,760 ME Yes Yes 19 #2 Coal-Fired Boiler (converted to NG) 8,760 ME Yes Yes 17 "A" & "B" Calciners (converted to NG) 8,760 ME/DE Yes Yes 2A Ore Crusher Building #1 8,760 DE Yes Yes 6A Product Silo - Top #1 8,760 DE Yes Yes 6B Product Silo - Bottom #1 8,760 DE Yes Yes 07 Product Loadout Station 8,760 DE Yes Yes 15 DR-1 & 2 Steam Tube Dryers 8,760 DE Yes Yes 16 Dryer Area 8,760 DE Yes Yes 25 Alkaten Crushing 8,760 E No Yes 26 DR-3 Alkaten Product Dryer 8,760 E No Yes 27 Alkaten Product Bagging & Loadout 8,760 E No Yes 30 Lime Bin #1 8,760 E No Yes 31 Lime Bin #2 8,760 E No Yes 33 Sulfur Burner 8,760 E No Yes 35 Sulfite Dryer 8,760 E No Yes 36 Sulfite Product Bin #1 8,760 E No Yes 37 Sulfite Product Bin #2 8,760 E No Yes 38 Sulfite Product Bin #3 8,760 E No Yes 44 Lime Unloading 4,380 E No Yes 46 Ore Transfer Station 8,760 DE Yes Yes 48 "C" Calciner 8,760 DE Yes Yes 50 "C" Train Dryer Area 8,760 DE Yes Yes 51 Product Dryer #5 8,760 DE Yes Yes 52 Product Silo - Top #2 8,760 DE Yes Yes 53 Product Silo - Bottom #2 8,760 DE Yes Yes 54 T-200 Storage Bin 8,760 E No Yes 62 Carbon Bin 8,760 E No Yes 63 Perlite Bin 8,760 E No Yes 66 Carbon/Perlite 8,760 E No Yes 68 Trona Products Bagging Silo 8,760 E No Yes 70 Sodium Sulfite Bagging Silo 8,760 E No Yes 71 Metabisulfite Bagging Silo 8,760 E No Yes 72 MBS Soda Ash Feed Silo 8,760 E No Yes

30 Annual WDEQ Operation In Source ID Source Description (hr/yr) Type* SIA? In Full? 73 Metabisulfite Dryer 8,760 E No Yes 76 "D" Train Primary Ore Screening 8,760 DE Yes Yes 79 Ore Transfer Point 8,760 DE Yes Yes 80 "D" Ore Calciner 8,760 DE Yes Yes 81 "D" Train Dryer Area 8,760 DE Yes Yes 82 DR-6 Product Dryer 8,760 DE Yes Yes 88 Trona Products Transloading #2 8,760 E No Yes 88b Trona Products Transloading #3 8,760 E No Yes 92 Trona Products Bin #2 8,760 E No Yes 93 Trona Products Rail Loadout 8,760 E No Yes 94 Sulfite Loadout 8,760 E No Yes 95 Trona Products Loadout Bin 8,760 E No Yes 96 T-200 TPX Bin #1 8,760 E No Yes 97 Soda Ash TPX 8,760 E No Yes 98 TPX Area 8,760 E No Yes 99 Crusher Baghouse #2 8,760 DE Yes Yes 101 Trona Products Dryer DR-7 8,760 E No Yes 102 Trona Products Loadout and Silo 8,760 E No Yes 103 East Ore Reclaim 8,760 DE Yes Yes 104 West Ore Reclaim 8,760 DE Yes Yes 105 S-300 Dryer #1 8,760 E No Yes 106 S-300 Silo and Rail Loadout #1 8,760 E No Yes 109 NG-fired Package Boiler 8,760 E Yes Yes E3 Waukesha F18GSI (GVBH compressor) 8,760 E No Yes E4 GM 8.1L (GVBH Pump) 8,760 E No Yes E5 GM 4.3L (GVBH Pump) 8,760 E No Yes MV Mine Vent 8,760 E No Yes GVBH Fl GVB Flare (Gas Incinerator) 8,760 E No Yes 901 Cooling Tower - High Flow 8,760 E No Yes 902 Cooling Tower - Low Flow 8,760 E No Yes --- Katolight SENL80FGC4 NG-fired 8,760 E No Yes Generator CH010 MikroPul 25S-10-20 Baghouse 8,760 CN Yes Yes E7 GVBH Generator (88 hp GM 5.7 L) 8,760 E No Yes E8 GVBH Generator (88 hp GM 5.7 L) 8,760 E No Yes E9 Waukesha H24GSI Engine - Compressor 8,760 E No Yes EG-3 Caterpillar 3456 500 E No Yes ** (Emergency Shaft Generator)

31 Annual WDEQ Operation In Source ID Source Description (hr/yr) Type* SIA? In Full? EG-4a Volvo TAD1353 GE (Main Shaft Emer. 500 E No Yes ** Gen.) EG-4b Volvo TAD1353 GE (Main Shaft Emer. 500 E No Yes ** Gen.) EG-4c Volvo TAD1353 GE (Main Shaft Emer. 500 E No Yes ** Gen.) FRP Emergency Fire Pump Engine 500 E No Yes ** EG-5a Perkins Engine #1 (619 hp) 100 E No Yes ** EG-5b Perkins Engine #2 (619 hp) 100 E No Yes ** EG-5c Perkins Engine #3 (619 hp) 100 E No Yes **

* Type: CN = New Contemporaneous, CE = Existing Contemporaneous, DE = Debottlenecked Existing Source, ME = Modified Existing, E = Existing Source, New = New Project Source. ** Emergency source: assumed to operate no more than 4 hours per day during normal facility operations.

32 6.3.1 Emissions for the SIA Analysis The PSD modeling analysis involves two phases: a preliminary analysis (referred to as SIA) and, if necessary, a full impact analysis. The preliminary analysis estimates ambient concentrations resulting from the proposed project for pollutants that trigger PSD requirements.

The results of the preliminary analysis determine whether a full impact analysis (facility plus competing regional sources) for a particular pollutant is necessary. If the ambient impacts from the preliminary analysis are greater than the SIL (see Table 6-1), then the extent of the SIA of the proposed project is to be determined.

Per previous approval for the BO-4 PSD modeling analyses in 2013, Solvay utilized an SIA approach with WDEQ to make use of the post-project vs. pre-project changes in short-term emissions where appropriate in the short-term modeling analyses.4 Solvay’s proposed approach as approved by WDEQ for all short- term averaging periods in the significant impact analyses (i.e., 24-hour PM, short-term CO, etc.) is as follows: For each existing source, the modeled net emissions increase was the PTE emissions rate (lb/hr; post-project) minus the maximum actual short-term emissions rate (lb/hr; pre-project). The maximum actual short-term emissions rate was selected as the highest actual short-term emissions rate that occurred during any time over a two-year period when this data was available. Note that for some sources (mostly combustion sources), Solvay analyzed its production data and determined that production rates were much lower than permitted allowable production rates. In these instances, Solvay chose to utilize average short-term emission rates to define pre-project, short-term emissions, rather than utilizing a maximum short-term emission rate. These average emission data were derived from Solvay’s annual emissions reports, which are provided to WDEQ.

The regulations for the PSD applicability calculations (to determine if modification is major or minor) allow for the selection of any two-year period over any previous ten years for emissions netting purposes. For Solvay, PSD applicability for PM and CO utilized 2016 and 2017 data to determine the BAE for the PSD applicability calculations. Solvay determined the maximum actual emissions for modeling using these same years.

For the annual average impact analyses, to determine the long-term SIA emissions for modeling, the actual annual emissions (two-year average) were subtracted from the annual average PTE.

If the maximum impact (or the three-year average maximum impact for the probabilistic standards; 24- hour and annual PM2.5) using these emissions was less than the applicable SIL, then the analysis was assumed complete for that pollutant and averaging time. If the pollutant impact exceeded the SIL, a full impact analysis was conducted, which included impacts from nearby sources as discussed further in Section 6.7.2.

4 E-mail from J. Nall, WDEQ, to T. Martin, Air Sciences Inc., RE: Solvay PSD: Modeling Information (fugitive PM and ambient boundary), October 8, 2012.

33 A summary of the SIA emission rates utilized in the SIL analysis is provided in Table 6-3 through Table 6-5. These tables also provide the details of the emissions calculations used to determine the SIA emissions utilized in the SIA modeling analyses. Note that PM10 emissions were conservatively utilized to define the PM2.5 SIA for all Solvay sources.

34 Table 6-3. SIA Emissions: Short-term PM

Max. Actual PM PTE Daily Operating WDEQ Emissions Hours Max. Actual Daily PM SIA Emissions; PTE SIA Emissions; PTE Source ID Source Description Type* (lb/hr) (2016/2017) Emissions, 2016/2017 (lb/hr) **** - Max. Actual (lb/hr) - Max. Actual (g/sec) 110 "E" Train Dryer Area Baghouse *** New 0.8 ------0.8 0.1030 111 DR-8 Product Dryer *** New 3.7 ------3.7 0.4622 17 "A" & "B" Calciners (converted to NG) ME/DE 22.0 24 24.4 -2.4 0 18 #1 Boiler (converted to NG) ME 2.9 24 2.79 0.1 0.0118 19 #2 Boiler (converted to NG) ME 2.9 24 2.41 0.5 0.0597 2A ** Ore Crusher Building #1 DE 1.6 24 1.6 0 0 6A ** Product Silo - Top #1 DE 0.3 24 0.3 0 0 6B ** Product Silo - Bottom #1 DE 0.51 24 0.51 0 0 7 ** Product Loadout Station DE 1.2 24 1.2 0 0 15 DR-1 & 2 Steam Tube Dryers DE 3 24 0.63 2.37 0.2986 16 ** Dryer Area DE 0.9 24 0.9 0 0 46 ** Ore Transfer Station DE 0.71 24 0.71 0 0 48 "C" Calciner DE 8 24 6.71 1.29 0.1625 50 ** "C" Train Dryer Area DE 0.7 24 0.7 0 0 51 Product Dryer #5 DE 2.4 24 0.16 2.24 0.2822 52 ** Product Silo - Top #2 DE 0.5 24 0.5 0 0 53 ** Product Silo - Bottom #2 DE 0.45 24 0.45 0 0 76 ** "D" Train Primary Ore Screening DE 2.45 24 2.45 0 0 79 ** Ore Transfer Point DE 0.84 24 0.84 0 0 80 "D" Ore Calciner DE 10 24 8.93 1.07 0.1348 81 ** "D" Train Dryer Area DE 0.5 24 0.5 0 0 82 DR-6 Product Dryer DE 3.45 24 1.16 2.29 0.2885 99 ** Crusher Baghouse #2 DE 3.2 24 3.2 0 0 103 ** East Ore Reclaim DE 0.33 24 0.33 0 0 104 ** West Ore Reclaim DE 0.27 24 0.27 0 0 109 NG-fired Package Boiler DE 1.89 24 0.94 0.95 0.1197 CH010 MikroPul 25S-10-20 Baghouse *** CN 0.2 ------0.2 0.0252

* Type: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source, CN = New Contemporaneous. ** Due to particulate emissions from these sources being a function of baghouse airflow and design specifications (e.g., grain loading) and not a function of production rates, the max. daily actual emissions are equal to the daily PTE emissions (there are no changes in short-term emissions). *** Modeled emissions for these sources are PTEs. **** Max. actual daily emissions for the following non-baghouse sources conservatively utilize the highest average daily emissions from either 2016 or 2017 (i.e., derived from WDEQ annual reports): #15, #17, #18, #19, #48, #51, #80, #82, #109. For example in 2016, source #48 operated 8,420 hours with reported PM emissions of 28.25 tpy (WDEQ annual reports). Thus, the average actual emission rate for 2016 for the source equals 6.71 lb/hr (28.25 tpy x 2000 lb/ton / 8,420 hr/yr = 6.71 lb/hr). Note: the conversion of #17 from coal to NG combustion results in a negative SIA emission rate; therefore, #17 is not modeled in the SIA analysis.

35 Table 6-4. SIA Emissions: Long-term PM

Allowable PM PTE 2016/2017 Average SIA Emissions; PTE WDEQ Annual Emissions Actual Emissions SIA Emissions; - Max. Actual Source ID Source Description Type* Operation (hr/yr) (tpy) (tpy) PTE - Actual (tpy) (g/sec) 110 "E" Train Dryer Area Baghouse ** New 8,760 3.6 --- 3.6 0.1030 111 DR-8 Product Dryer ** New 8,760 16.1 --- 16.1 0.4622 17 "A" & "B" Calciners (converted to NG) ME/DE 8,760 96.4 49.4 47.0 1.3521 18 #1 Boiler (converted to NG) ME 8,760 12.6 11.7 0.9 0.0260 19 #2 Boiler (converted to NG) ME 8,760 12.6 10.1 2.5 0.0727 2A Ore Crusher Building #1 DE 8,760 7.0 7.0 0 0 6A Product Silo - Top #1 DE 8,760 1.3 1.3 0 0 6B Product Silo - Bottom #1 DE 8,760 2.2 0.1 2.2 0.0626 7 Product Loadout Station DE 8,760 5.3 2.6 2.6 0.0756 15 DR-1 & 2 Steam Tube Dryers DE 8,760 13.1 2.6 10.5 0.3019 16 Dryer Area DE 8,760 3.9 3.8 0.2 0.0050 46 Ore Transfer Station DE 8,760 3.1 3.1 0 0 48 "C" Calciner DE 8,760 35.0 27.9 7.1 0.2042 50 "C" Train Dryer Area DE 8,760 3.1 3.0 0.1 0.0024 51 Product Dryer #5 DE 8,760 10.5 0.7 9.8 0.2828 52 Product Silo - Top #2 DE 8,760 2.2 2.1 0.0 0.0013 53 Product Silo - Bottom #2 DE 8,760 2.0 0.9 1.0 0.0297 76 "D" Train Primary Ore Screening DE 8,760 10.7 10.5 0.2 0.0067 79 Ore Transfer Point DE 8,760 3.7 3.6 0.1 0.0023 80 "D" Ore Calciner DE 8,760 43.8 30.6 13.2 0.3804 81 "D" Train Dryer Area DE 8,760 2.2 2.1 0.1 0.0025 82 DR-6 Product Dryer DE 8,760 15.1 4.9 10.2 0.2943 99 Crusher Baghouse #2 DE 8,760 14.0 14.0 0 0 103 East Ore Reclaim DE 8,760 1.4 1.4 0 0 104 West Ore Reclaim DE 8,760 1.2 1.2 0 0 109 NG-fired Package Boiler DE 8,760 8.3 3.4 4.9 0.1414 CH010 MikroPul 25S-10-20 Baghouse ** CN 8,760 0.9 --- 0.9 0.0252

* Type: New = New Project Source, ME = Modified Existing Source , DE = Debottlenecked Existing Source, CN = New Contemporaneous. ** Modeled emissions for these sources are PTEs.

36 Table 6-5. SIA Emissions: Short-term CO

CO PTE WDEQ Emissions Max. Actual Short-term CO SIA Emissions; PTE - SIA Emissions; PTE - Source ID Source Description Type* (lb/hr) Emissions, 2016/2017 (lb/hr) **** Max. Actual (lb/hr) Max. Actual (g/sec)

111 DR-8 Product Dryer ** New 292 --- 292.0 36.7912 17 "A" & "B" Calciners (converted to NG) ** ME / DE 1524 371.1 1152.9 145.2560 18 #1 Boiler (converted to NG) ** ME 28.6 12.0 16.7 2.1026 19 #2 Boiler (converted to NG) ** ME 28.6 16.6 12.1 1.5218 15 DR-1 & 2 Steam Tube Dryers DE ------0 *** 0 *** 48 "C" Calciner DE 762 273.1 488.9 61.6029 51 Product Dryer #5 DE 225 36.2 188.8 23.7924 80 "D" Ore Calciner DE 1048 588.1 459.9 57.9461 82 ** DR-6 Product Dryer DE 300 38.8 261.2 32.9080 109 NG-fired Package Boiler ** DE 9.4 9.4 0 0

* Type: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source. ** Modeled emissions for these sources are PTEs. *** Source #15 fed by heat from boilers only, old preheaters on Source #15 are no longer used so there are no actual gaseous emissions. Solvay no longer wishes to use the Source #15 preheaters and wishes to eliminate them from the facility’s air permit. **** Max. actual hourly emissions for the following combustion sources conservatively utilize the highest average hourly emissions from either 2016 or 2017 (i.e., derived from WDEQ annual reports): #17, #18, #19, #48, #51, #80, #82, #109. For example in 2016, source #48 operated 8,420 hours with reported CO emissions of 1149.7 tpy (WDEQ annual reports). Thus, the average actual emission rate for 2016 for the source equals 273.1 lb/hr (1149.7.0 tpy x 2000 lb/ton / 8,420 hr/yr = 273.1 lb/hr).

37 6.3.2 Emissions for the NAAQS and Increment Analyses For the NAAQS analyses, the model was run with sources operating at PTE emission rates. For the PSD increment analyses, the model was run with the PSD-consuming sources (facility and competing) to demonstrate compliance with the PSD increments. Section 6.3.3 describes the PM2.5 increment inventory, which considers the net changes in emissions since the major source baseline date for PM2.5.

Table 6-6 shows CO PTE emission rates used in the full CO NAAQS analysis.

Table 6-7 the shows the particulate PTE emission rates used in the full particulate NAAQS analyses for

PM2.5. Note that PM10 emissions are shown in the table since the PM2.5 emissions are derived from the

PM10 emissions. However, the PM10 emissions are not used for modeling since PM10 impacts from the SIA analyses were not significant and a NAAQS and PSD increment analysis is not necessary for PM10.

Table 6-8 provides more details regarding the particulate PTE emission rates utilized in the modeling analysis for emergency and fugitive sources.

38 Table 6-6. Modeled Emission Rates – Solvay Facility; CO PTE Emissions

PTE Emissions PTE Emissions Source ID Source Description CO (lb/hr) CO (g/sec) 111 DR-8 Product Dryer 292 36.7912 17 "A" & "B" Calciners (converted to NG) 1524 192.0198 18 #1 Coal-Fired Boiler (converted to NG) 28.6 3.6083 19 #2 Coal-Fired Boiler (converted to NG) 28.6 3.6083 26 DR-3 Alkaten Product Dryer 0.07 0.0088 48 "C" Calciner 762 96.0099 51 Product Dryer #5 225 28.3494 80 "D" Ore Calciner 1048 132.0451 82 DR-6 Product Dryer 300 37.7992 101 Trona Products Dryer DR-7 0.2 0.0252 109 NG-fired Package Boiler 9.4 1.1844 E3 Waukesha F18GSI (GVBH Compressor) 0.9 0.1134 E4 GM 8.1L (GVBH Pump) 0.5 0.0630 E5 GM 4.3L (GVBH Pump) 0.3 0.0378 MV Mine Vent 7.8 0.9828 GVBH Fl GVB Flare (Gas Incinerator) 3.4 0.4309 KATO Katolight SENL80FGC4 NG-Fired Generator 0.3 0.0378 E7 GVBH Generator (88 hp GM 5.7L) 0.2 0.0252 E8 GVBH Generator (88 hp GM 5.7L) 0.2 0.0252 E9 Waukesha H24GSI Engine - Compressor 2.3 0.2898 EG3 Caterpillar 3456 (Emergency Shaft Generator) 12.9 1.6254 EG4a Volvo TAD1353 GE (Main Shaft Emer. Gen.) 3.5 0.4410 EG4b Volvo TAD1353 GE (Main Shaft Emer. Gen.) 3.5 0.4410 EG4c Volvo TAD1353 GE (Main Shaft Emer. Gen.) 3.5 0.4410 FRP Emergency Fire Pump Engine 1.9 0.2432 EG5a Perkins Engine #1 (619 HP) 2.4 0.3074 EG5b Perkins Engine #2 (619 HP) 2.4 0.3074 EG5c Perkins Engine #3 (619 HP) 2.4 0.3074 Volume Sources RAIL Rail Switching Engines * 0.0045 lb/hr/vol. 5.7E-04 g/sec./vol.

* Only the portions of track located within each SIA (not the entire ~16 km track length) are considered for the full modeling analyses. These emissions are provided as lb/hr/volume, which is a constant for each pollutant.

39 Table 6-7. Modeled Emission Rates – Solvay Facility; Particulate PTE Emissions

PM10 PTE Emissions PM2.5 / PM2.5 PTE Emissions

Source 1-hour 24-hour Annual PM10 1-hour 24-hour Annual Source Description ID Type (lb/hr) (g/sec) (g/sec) Ratio (lb/hr) (g/sec) (g/sec) 110 “E” Train Dryer Area Baghouse Baghouse 0.82 0.1030 0.1030 0.6 0.49 0.0618 0.0618 111 DR-8 Product Dryer Combustion 3.7 0.4622 0.4622 1 3.67 0.4622 0.4622 17 "A" & "B" Calciners (converted to NG) Combustion 22.0 2.7735 2.7735 1 22.0 2.7735 2.7735 18 #1 Boiler (converted to NG) Combustion 2.9 0.3633 0.3633 1 2.88 0.3633 0.3633 19 #2 Boiler (converted to NG) Combustion 2.9 0.3633 0.3633 1 2.88 0.3633 0.3633 2A Ore Crusher Building #1 Baghouse 1.6 0.2016 0.2016 0.6 0.96 0.1210 0.1210 6A Product Silo - Top #1 Baghouse 0.3 0.0378 0.0378 0.6 0.18 0.0227 0.0227 6B Product Silo - Bottom #1 Baghouse 0.51 0.0643 0.0643 0.6 0.31 0.0386 0.0386 07 Product Loadout Station Baghouse 1.2 0.1512 0.1512 0.6 0.72 0.0907 0.0907 15 DR-1 & 2 Steam Tube Dryers Scrubber 3 0.3780 0.3780 1 3.00 0.3780 0.3780 16 Dryer Area Baghouse 0.9 0.1134 0.1134 0.6 0.54 0.0680 0.0680 25 Alkaten Crushing Baghouse 1 0.1260 0.1260 0.6 0.60 0.0756 0.0756 26 DR-3 Alkaten Product Dryer Baghouse 0.55 0.0693 0.0693 0.6 0.33 0.0416 0.0416 27 Alkaten Product Bagging & Loadout Baghouse 0.5 0.0630 0.0630 0.6 0.30 0.0378 0.0378 30 Lime Bin #1 Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 31 Lime Bin #2 Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 35 Sulfite Dryer Scrubber 1.4 0.1764 0.1764 1 1.40 0.1764 0.1764 36 Sulfite Product Bin #1 Bin Vent 0.1 0.0126 0.0126 1 0.10 0.0126 0.0126 37 Sulfite Product Bin #2 Bin Vent 0.1 0.0126 0.0126 1 0.10 0.0126 0.0126 38 Sulfite Product Bin #3 Bin Vent 0.1 0.0126 0.0126 1 0.10 0.0126 0.0126 44 Lime Unloading Baghouse 0.18 0.0227 0.0227 0.6 0.11 0.0136 0.0136 46 Ore Transfer Station Baghouse 0.71 0.0895 0.0895 0.6 0.43 0.0537 0.0537 48 "C" Calciner Combustion 8 1.0080 1.0080 1 8.00 1.0080 1.0080 50 "C" Train Dryer Area Baghouse 0.7 0.0882 0.0882 0.6 0.42 0.0529 0.0529 51 Product Dryer #5 Combustion 2.4 0.3024 0.3024 1 2.40 0.3024 0.3024 52 Product Silo - Top #2 Baghouse 0.5 0.0630 0.0630 0.6 0.30 0.0378 0.0378 53 Product Silo - Bottom #2 Baghouse 0.45 0.0567 0.0567 0.6 0.27 0.0340 0.0340 54 T-200 Storage Bin Bin Vent 0.19 0.0239 0.0239 1 0.19 0.0239 0.0239 62 Carbon Bin Bin Vent 0.13 0.0164 0.0164 1 0.13 0.0164 0.0164 63 Perlite Bin Bin Vent 0.14 0.0176 0.0176 1 0.14 0.0176 0.0176 66 Carbon/Perlite Scrubber 0.58 0.0731 0.0731 1 0.58 0.0731 0.0731 68 Trona Products Bagging Silo Baghouse 0.36 0.0454 0.0454 0.6 0.22 0.0272 0.0272 70 Sodium Sulfite Bagging Silo Baghouse 0.27 0.0340 0.0340 0.6 0.16 0.0204 0.0204 71 Metabisulfite Bagging Silo Baghouse 0.27 0.0340 0.0340 0.6 0.16 0.0204 0.0204 72 MBS Soda Ash Feed Silo Baghouse 0.07 0.0088 0.0088 0.6 0.04 0.0053 0.0053

40 Table 6-7. Modeled Emission Rates – Solvay Facility; Particulate PTE Emissions (cont’d)

PM10 PTE Emissions PM2.5 / PM2.5 PTE Emissions Source 1-hour 24-hour Annual PM10 1-hour 24-hour Annual Source Description ID Type (lb/hr) (g/sec) (g/sec) Ratio (lb/hr) (g/sec) (g/sec) 73 Metabisulfite Dryer Scrubber 0.9 0.1134 0.1134 1 0.90 0.1134 0.1134 76 "D" Train Primary Ore Screening Baghouse 2.45 0.3087 0.3087 0.6 1.47 0.1852 0.1852 79 Ore Transfer Point Baghouse 0.84 0.1058 0.1058 0.6 0.50 0.0635 0.0635 80 "D" Ore Calciner Combustion 10 1.2600 1.2600 1 10.00 1.2600 1.2600 81 "D" Train Dryer Area Baghouse 0.5 0.0630 0.0630 0.6 0.30 0.0378 0.0378 82 DR-6 Product Dryer Combustion 3.45 0.4347 0.4347 1 3.45 0.4347 0.4347 88 Trona Products Transloading #2 Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 88b Trona Products Transloading #3 Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 92 Trona Products Bin #2 Bin Vent 0.3 0.0378 0.0378 1 0.30 0.0378 0.0378 93 Trona Products Rail Loadout Baghouse 0.17 0.0214 0.0214 0.6 0.10 0.0129 0.0129 94 Sulfite Loadout Baghouse 0.3 0.0378 0.0378 0.6 0.18 0.0227 0.0227 95 Trona Products Loadout Bin Bin Vent 0.1 0.0126 0.0126 1 0.10 0.0126 0.0126 96 T-200 TPX Bin #1 Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 97 Soda Ash TPX Baghouse 0.1 0.0126 0.0126 0.6 0.06 0.0076 0.0076 98 TPX Area Baghouse 0.4 0.0504 0.0504 0.6 0.24 0.0302 0.0302 99 Crusher Baghouse #2 Baghouse 3.2 0.4032 0.4032 0.6 1.92 0.2419 0.2419 101 Trona Products Dryer DR-7 Baghouse 2 0.2520 0.2520 0.6 1.20 0.1512 0.1512 102 Trona Products Loadout and Silo Baghouse 0.6 0.0756 0.0756 0.6 0.36 0.0454 0.0454 103 East Ore Reclaim Baghouse 0.33 0.0416 0.0416 0.6 0.20 0.0249 0.0249 104 West Ore Reclaim Baghouse 0.27 0.0340 0.0340 0.6 0.16 0.0204 0.0204 105 S-300 Dryer #1 Baghouse 1.3 0.1638 0.1638 0.6 0.78 0.0983 0.0983 106 S-300 Silo and Rail Loadout #1 Baghouse 0.1 0.0126 0.0126 0.6 0.06 0.0076 0.0076 109 NG-fired Package Boiler Combustion 1.89 0.2381 0.2381 1 1.89 0.2381 0.2381 Cooling 901 Cooling Tower - High Flow 0.46 0.0581 0.0581 0.15 0.07 0.0088 0.0088 Tower Cooling 902 Cooling Tower - Low Flow 0.29 0.0361 0.0361 0.04 0.01 0.0014 0.0014 Tower

41 Table 6-7. Modeled Emission Rates – Solvay Facility; Particulate PTE Emissions (cont’d)

PM10 PTE Emissions PM2.5 / PM2.5 PTE Emissions 24- Source 1-hour 24-hour Annual PM10 1-hour Annual Source Description hour ID Type (lb/hr) (g/sec) (g/sec) Ratio (lb/hr) (g/sec) (g/sec) CH010 MikroPul 25S-10-20 Baghouse Baghouse 0.2 0.0252 0.0252 0.6 0.12 0.0151 0.0151 Caterpillar 3456 (Emergency Shaft EG3 * Combustion 0.6 0.0126 0.0043 1 0.60 0.0126 0.0043 Generator) EG4a * Volvo TAD1353 GE (Main Shaft Emer. Gen.) Combustion 0.2 0.0042 0.0014 1 0.20 0.0042 0.0014 EG4b * Volvo TAD1353 GE (Main Shaft Emer. Gen.) Combustion 0.2 0.0042 0.0014 1 0.20 0.0042 0.0014 EG4c * Volvo TAD1353 GE (Main Shaft Emer. Gen.) Combustion 0.2 0.0042 0.0014 1 0.20 0.0042 0.0014 FRP * Emergency Fire Pump Engine Combustion 0.63 0.0132 0.0045 1 0.63 0.0132 0.0045 EG5a * Perkins Engine #1 (619 hp) Combustion 0.15 0.0032 0.0002 1 0.15 0.0032 0.0002 EG5b * Perkins Engine #2 (619 hp) Combustion 0.15 0.0032 0.0002 1 0.15 0.0032 0.0002 EG5c * Perkins Engine #3 (619 hp) Combustion 0.15 0.0032 0.0002 1 0.15 0.0032 0.0002 Volume Sources ** 7.8E-05 7.8E-05 RAIL Rail Switching Engines Tailpipe N/A N/A 1 N/A N/A g/sec./vol. g/sec./vol.

* The emergency sources are assumed to operate 4 hr/day; the short term lb/hr emission rates are adjusted by 4/24 to determine a daily lb/hr emission rate. The short-term lb/hr emission rates are adjusted by 500/8760 to determine an annualized lb/hr modeled emission rate for: EG3, EG4a, EG4b, EG4c, FRP. The short-term lb/hr emission rates are adjusted by 100/8760 to determine an annualized lb/hr modeled emission rate for: EG5a, EG5b, EG5c. ** For these fugitive sources, per WDEQ policy, short-term PM emissions are not modeled. PM emission rates provided in the table are the annualized lb/hr rates representative of long-term emissions for annual PM modeling.

42 Table 6-8. Modeled Emission Rates – Solvay Facility Emergency and Fugitive Sources; Particulate PTE Emissions

Operations PM PTE Emissions Hourly Daily (hr/day) (hr/yr) Daily (g/sec) Annual (lb/hr) Annual (g/sec) Source ID Source Description (lb/hr) (lb/hr) Point Sources (Emergency Sources) * EG3 Caterpillar 3456 (Emergency Shaft Generator) 4 500 0.60 0.10 0.0126 0.03 0.0043 EG4a Volvo TAD1353 GE (Main Shaft Emer. Gen.) 4 500 0.20 0.03 0.0042 0.01 0.0014 EG4b Volvo TAD1353 GE (Main Shaft Emer. Gen.) 4 500 0.20 0.03 0.0042 0.01 0.0014 EG4c Volvo TAD1353 GE (Main Shaft Emer. Gen.) 4 500 0.20 0.03 0.0042 0.01 0.0014 FRP Emergency Fire Pump Engine 4 500 0.63 0.11 0.0132 0.04 0.0045 EG5a Perkins Engine #1 (619 HP) 4 100 0.15 0.03 0.0032 0.002 0.0002 EG5b Perkins Engine #2 (619 HP) 4 100 0.15 0.03 0.0032 0.002 0.0002 EG5c Perkins Engine #3 (619 HP) 4 100 0.15 0.03 0.0032 0.002 0.0002

Volume Sources (Fugitive) **

0.0006 7.8E-05 RAIL Rail Switching Engines 24 8,760 N/A N/A N/A lb/hr/vol. g/sec./vol.

* For the emergency sources, the short-term lb/hr emission rates are adjusted by 4/24 to determine a daily lb/hr modeled emission rate. The short-term lb/hr emission rates are adjusted by 500/8760 to determine an annualized lb/hr emission rate for modeling. ** For these fugitive sources, per WDEQ policy, short-term PM emissions are not modeled. PM emission rates provided in the table are the annualized lb/hr rates representative of long-term emissions for annual PM modeling.

43 PM2.5/PM10 MASS FRACTIONS

As shown in Table 6-7, for the particulate PTE emission rates, it was conservatively assumed that the

PM2.5 emission rate for each Solvay combustion source (and non-baghouse material handling sources like bin vents) was equal to the PM10 emission rate. For its baghouses, Solvay analyzed several sources of information to derive a conservative PM2.5/PM10 mass fraction. The PM2.5/PM10 mass fraction value of 0.6 was previously utilized for the BO-4 PSD project approved by WDEQ in 2013. The details supporting the use of this value are provided below.

First, AP-42, Appendix B.2 provides generalized particulate size distribution data, which were used to

derive generic PM2.5/PM10 mass fractions. This AP-42 section also gives example calculations for determining both uncontrolled and controlled particle size-specific emission rates. For AP-42 Categories 3 (Process: Mechanically Generated, Materials: Aggregate, Unprocessed Ores) and 4 (Process: Mechanically Generated, Materials: Processed Ores and Nonmetallic Minerals), generalized AP-42 particle size distribution information assuming baghouse (fabric filter) controls was utilized and emission rates before and after controls were calculated for several particle size categories. As shown in Table 6-9, Solvay determined generic PM2.5/PM10 mass fractions for baghouses ranging from 0.26 (Category 3) to 0.29 (Category 4).

Table 6-9. Generic PM2.5/PM10 Mass Fractions for Baghouses

Category 3: Particle Size (micrometers) 1 Category 4: Particle Size (micrometers) 1 Uncontrolled Size Emissions 2.5 6 10 2.5 6 10

Generic Distribution (cumulative %) 2 15% 34% 51% 30% 62% 85%

Cumulative Mass =< Particle Size Emissions 0.15 0.34 0.51 0.30 0.62 0.85 (tpy); Unit Emissions (1 tpy)

Category 3: Particle Size (micrometers) Category 4: Particle Size (micrometers)

Controlled Size Emissions 0 - 2.5 2.5 - 6 6 - 10 0 - 2.5 2.5 - 6 6 - 10

Collection Efficiency 3 99.0% 99.5% 99.5% 99.0% 99.5% 99.5% Mass in size range before control (tpy) 4 0.15 0.34 0.51 0.30 0.62 0.85 Mass in size range after control (tpy) 0.0015 0.0017 0.0026 0.0030 0.0031 0.0043 Cumulative Mass (tpy) 0.0015 0.0032 0.0058 0.0030 0.0061 0.0104

Controlled PM2.5/PM10 Mass Fraction 5 0.26 0.29

1 Less than or equal to the particle size emissions. From AP-42, Appendix B.2, Table B.2.2 for fabric filters for categories 3 and 4. Category 3 = Process: Mechanically Generated, Materials: Aggregate, Unprocessed Ores. Category 4 = Process: Mechanically Generated, Materials: Processed Ores and Nonmetallic Minerals. 2 Cumulative percentage equal to or less than the size from AP-42, Appendix B.2, Table B.2.2. 3 From AP-42, Appendix B.2, Table B.2-3 for fabric filters for categories 3 and 4. 4 Uncontrolled size data are cumulative percentages equal to or less than the size. Control efficiency data apply only to the size range and are not cumulative. 5 Based on cumulative mass values.

44 Second, Solvay performed a PM2.5 stack test on its #76 baghouse. This test was not performed in conjunction with a concurrent PM10 stack test, but the test did indicate that measured PM2.5 emissions

(0.005 gr/dscf) are a small fraction (~22 percent) of the PM10 emission limit for the source (0.022 gr/dscf).

Third, Solvay has also reviewed stack test summary data for three baghouses in the soda ash industry that indicated an average PM2.5/PM10 mass fraction of around 0.22 for all tests (0.13, 0.19, and 0.33 for baghouses #1, #2, and #3, respectively); consistent with the AP-42 generalized mass fractions and Solvay stack test for source #76. There was a single outlier in these test data, which indicated a higher

PM2.5/PM10 mass fraction of 0.56 for a single test for baghouse #3. However, the average PM2.5/PM10 mass fraction of the four tests for baghouse #3 was 0.33.

Thus, to be conservative, Solvay used a PM2.5/PM10 mass fraction of 0.6 for the baghouses based on the highest reported stack test ratio. This value is at least a factor of two higher than the AP-42 factors and is higher than all stack test data reviewed by Solvay.

As provided in Appendix E, Solvay has calculated emissions estimates and characterized selected fugitive/mobile sources (railroad) at the facility for modeling purposes. These emissions and source characterizations described below were previously utilized for the BO-4 PSD project approved by WDEQ in 2013. Note that the ARGO project will remove the DECA road and coal roads fugitive sources from the facility, so the railroad is the main mobile source at the facility.

MOBILE SOURCES — Railroad

Solvay has quantified railroad emissions, which constitute the majority of mobile emissions at the facility, and these sources are included in the impact analysis where necessary. The railroad sources were characterized by strings of volume sources placed along their route. Following EPA guidance, the width of the volume sources was set to the width of the road plus 6 meters. Sigma y was set to the volume source width divided by 2.15. The volume sources were spaced approximately two volume widths apart using the ISCST3 alternative line source representation. The release height was set to 1.7/2 times the vehicle height.

For the railroad switcher locomotives, exhaust emissions were calculated based on Solvay’s monthly fuel use and EPA's Emissions Factors for Locomotives (EPA-420-F-025, April 2009, Table 3). The total railroad emissions were based on a 15.8 kilometer total track length (532 total volume sources) spanning north from the Solvay facility to a main rail line. Because emissions from the railroad are spread over a large distance, the railroad emissions sources closer to the facility were expected to combine with other plumes from the Solvay facility to determine maximum modeled impacts. Thus, for the railroad sources, only the volume sources located within the SIA for each pollutant were explicitly modeled in the full NAAQS modeling runs to provide for reasonable model run times while still providing a conservative modeling estimate.

The calculations for the railroad are provided in detail on Page 4 of Appendix E.

45 6.3.3 Emissions for the PM2.5 Increment Analysis For the PSD increment analyses, the model was run with the PSD-consuming sources (facility and competing) to demonstrate compliance with the PSD increments. For PM2.5, the increment-consuming sources were a subset of the PM10-emitting sources listed in Table 6-7. The major source baseline date for

PM2.5 is October 20, 2010, so only changes in PM2.5 emissions at Solvay since the major source baseline date consume increment.

PSD Permit Actions Since 2010

To determine the increment-consuming sources emissions inventory, Solvay has evaluated the sources associated with three major modification/PSD permitting actions at the facility since October 2010. For the Solvay ARGO PSD project, these sources include the new sources (#110, #111), existing modified sources (#17, #18, and #19), and the associated ARGO project debottlenecked sources. Since October 2010, two additional previous PSD projects occurred at the facility; the BO-4 production expansion project in 2013 and the SAS-300 PSD project in 2017. All project sources from these major modifications are accounted for in the PM2.5 increment-consuming emissions inventory.

Contemporaneous and Other PM2.5 Sources Permitted Since 2010

From the ARGO project contemporaneous source analysis (Appendix D), only three creditable contemporaneous permit actions are related to the ARGO project at the Solvay facility:

 Waiver P0020929 on 06/21/2016 (PM increases for sources #6A, #6B, #7, #52, #53, #81, #82 and no emissions changes or emissions decreases for several other PM sources),

 Waiver P0022664 on 03/15/2017 (Longwall Water Evaporator Vent),

 Permit No. P0023144 on 06/12/2017 (MikroPul 25S-10-20 Baghouse [source CH010]).

For Waiver P0020929, the sources with PM increases are a subset of the same sources as the debottlenecked ARGO project sources. Thus, the ARGO project debottlenecked sources list is utilized as the main source list to define PM2.5 increment-consuming emissions for these sources; sources from Waiver P0020929 are already included on the ARGO project list. The Longwall Water Evaporator Vent is an insignificant source of particulate emissions. Thus, the ARGO project contemporaneous source that does consume PM2.5 increment is the MikroPul 25S-10-20 Baghouse (source CH010).

Per the previously approved BO-4 PSD analyses in 2013, there were only three creditable permit actions for contemporaneous sources at the Solvay facility since the PM2.5 major source baseline date of October 20, 2010:

 MD-11835 on 06/21/2011 (sources EG-3, EG-4a, EG-4b, EG-4c),

 Waiver wv-11853 on 04/14/2011 (sources TEG Dehydration Unit, Two Reboilers Heaters), and

46  Waiver-11822 on 04/29/2011 (Katolight SENL80FGC4 NG-fired Generator).

The TEG Dehydration Unit and the Katolight Generator are not sources of particulate emissions and do not consume PM2.5 increment. The Two Reboilers Heaters are an insignificant source of particulate emissions. Thus, the BO-4 project contemporaneous sources that do consume PM2.5 increment are EG-3, EG-4a, EG-4b, and EG-4c.

Additional non-PSD permitting actions (i.e., “other” actions) at the Solvay facility were evaluated to determine if additional sources consume PM2.5 increment since the PM2.5 major source baseline date of October 20, 2010:

 Waiver wv-14727 on 05/03/2013 (sources E7 and E8),

 Permit No. MD-16104 on 07/14/2014 (source E9),

 Waiver wv-16878 on 11/06/2014 (Mine Gas Dehydration Unit #2), and

 Installation of sources EG5a (Perkins Engine #1), EG5b (Perkins Engine #2), and EG5c (Perkins Engine #3).

Source E7, E8, and E9 are not sources of particulate emissions and do not consume PM2.5 increment. The Mine Gas Dehydration Unit #2 is an insignificant source of particulate emissions. Thus, the other sources that consume PM2.5 increment are EG5a (Perkins Engine #1), EG5b (Perkins Engine #2), and EG5c (Perkins Engine #3).

As previously discussed with WDEQ, the post-project vs. PM2.5 baseline conditions changes in short-term 5 PM2.5 emissions were utilized where possible for the PM2.5 increment analysis. Solvay’s approach as approved by WDEQ for daily PM2.5 increment impacts is as follows: For each increment consuming source, the modeled net emissions increase (i.e., increment consumption) was the PTE emissions rate (lb/hr; post-project) minus the maximum actual short-term emissions rate (lb/hr; representative of baseline conditions). The maximum actual short-term emissions rate was selected as the highest actual short-term emissions rate that occurred during any time over a two-year period. Note that for some combustion sources, Solvay analyzed its production data and determined that production rates were much lower than permitted allowable production rates. In these instances, Solvay chose to utilize average short-term emission rates based on annual data provided to WDEQ in its annual emissions reports, rather than maximum short-term emission rates. The PM2.5 emissions for the analyses are conservatively assumed as PM10 emissions and any sources with net decreases in emissions (i.e., increment expanding sources) were set to zero.

5 E-mail from J. Nall, WDEQ, to T. Martin, Air Sciences Inc., RE: Solvay PSD: Modeling Information (fugitive PM and ambient boundary), October 8, 2012.

47 Because particulate emissions are a function of baghouse airflow and design specifications (e.g., grain loading) and not a function of production rates, baghouse sources do not consume PM2.5 increment on a short-term basis since there is no actual change in emissions since the PM2.5 baseline date.

Per previous communications with WDEQ for the BO-4 PSD project, Solvay is utilizing 2009 and 2010 for the characterization of both the short-term and annual PM2.5 baseline conditions for the PM2.5 increment consumption analyses. These years were selected to represent baseline conditions at the PM2.5 major source baseline date. Short-term PM2.5 baseline conditions were the highest daily emissions that occurred in either 2009 or 2010, and annual emissions that characterize the baseline conditions were the average of 2009 and 2010 annual emissions.

A listing of Solvay’s PM2.5 consuming sources considered in the impact analysis is provided in Table 6-10 and Table 6-11.

48 Table 6-10. 24-Hour PM2.5 Increment Consuming Sources at the Solvay Facility

Max. Actual Daily PM PTE Operating Max. Actual Daily PSD Increment PSD Increment WDEQ Emissions Hours PM Emissions, Emissions; PTE - Emissions; PTE - Source ID Source Description Note * (lb/hr) (2009/20210) 2009/2010 (lb/hr) Max. Actual (lb/hr) Max. Actual (g/sec)

Project and Other Sources Since Baseline Date Which Consume 24-Hour PM2.5 Increment 110 "E" Train Dryer Area Baghouse *** ARGO: New 0.8 ------0.82 0.1030 111 DR-8 Product Dryer *** ARGO: New 3.7 ------3.7 0.4622 15 *** DR-1 & 2 Steam Tube Dryers ALL, ARGO: DE 3.0 24 2.1 0.91 0.1147 17 *** "A" & "B" Calciners (converted to NG) ALL, ARGO: ME/DE 22.0 24 14.5 7.51 0.9465 18 *** #1 Boiler (converted to NG) ARGO: ME 2.9 24 2.5 0.40 0.0508 19 *** #2 Boiler (converted to NG) ARGO: ME 2.9 24 2.5 0.40 0.0507 48 *** "C" Calciner ALL, ARGO: DE 8.0 24 5.0 3.03 0.3818 51 *** Product Dryer #5 BO-4, ARGO: DE 2.4 24 0.9 1.50 0.1890 80 *** "D" Ore Calciner ALL, ARGO: ME/DE 10.0 24 8.9 1.09 0.1373 82 *** DR-6 Product Dryer BO-4, ARGO: ME/DE 3.45 24 2.5 0.91 0.1147 109 NG-fired Package Boiler ALL, ARGO: DE 1.89 24 --- 1.89 0.2381 Caterpillar 3456 (Emergency Shaft EG3 **** BO-4: E 0.10 ------0.10 0.0126 Generator) EG4a **** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 0.03 ------0.03 0.0042 EG4b **** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 0.03 ------0.03 0.0042 EG4c **** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 0.03 ------0.03 0.0042 EG5a **** Perkins Engine #1 (619 hp) Other: E 0.03 ------0.03 0.0032 EG5b **** Perkins Engine #2 (619 hp) Other: E 0.03 ------0.03 0.0032 EG5c **** Perkins Engine #3 (619 hp) Other: E 0.03 ------0.03 0.0032 CH010 MikroPul 25S-10-20 Baghouse ARGO: E 0.2 ------0.2 0.0252 * Note: There have been three PSD permit actions at the Solvay facility since 2010. BO-4 in 2013, SAS-300 in 2017, and the ARGO project here in 2019. Format above indicates if the source was part of one of these three projects / PSD permitting actions or ALL three of them. The right most note indicates that most recent permitting action for the source and either its source classification or if it was removed. Source classifications are as follows: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source, or E = Existing source (either contemporaneous to a PSD project or added to the facility since 2010, but not contemporaneous to particular PSD action). ** Due to particulate emissions from these sources being a function of baghouse airflow and design specifications (e.g., grain loading) and

not a function of production rates, these sources do not consume PM2.5 increment on a short-term basis since there is no actual change in emissions since the baseline date. *** These sources are conservatively modeled using an average daily actual emission rate (long-term) to represent a maximum actual daily emission rate. For example in 2010, source #17 operated 8,276 hours with reported PM emissions of 60.0 tpy (WDEQ annual reports). Thus, the average actual emission rate for 2010 for the source equals 14.5 lb/hr (60.0 tpy x 2000 lb/ton / 8,276 hr/yr = 14.5 lb/hr). **** During normal facility operating conditions, emergency generators are assumed to operate no more than 4 hours/day, max. lb/hr emissions are adjusted by 4/24 for modeling.

49 Table 6-10. 24-Hour PM2.5 Increment Consuming Sources at the Solvay Facility (cont’d)

Max. Actual Daily PM PTE Operating Max. Actual Daily PSD Increment PSD Increment WDEQ Emissions Hours PM Emissions, Emissions; PTE - Emissions; PTE - Source ID Source Description Note * (lb/hr) (2009/20210) 2009/2010 (lb/hr) Max. Actual (lb/hr) Max. Actual (g/sec)

Project and Other Sources Since Baseline Date Which Do Not Consume 24-Hour PM2.5 Increment 02A ** Ore Crusher Building #1 ALL, ARGO: DE 1.6 24 1.6 0 0 06A ** Product Silos - Top #1 BO-4, ARGO: DE 0.3 24 0.3 0 0 06B ** Product Silos - Bottom #1 BO-4, ARGO: DE 0.51 24 0.51 0 0 07 ** Product Loadout Station BO-4, ARGO: DE 1.2 24 1.2 0 0 10 ** Coal Crushing and Storage SAS-300, ARGO: Removed 0.3 24 0.3 0 0 11 ** Coal Transfer Station SAS-300, ARGO: Removed 0.2 24 0.2 0 0 14 ** Boiler Coal Boiler ARGO: Removed 0.4 24 0.4 0 0 16 ** Dryer Area BO-4, ARGO: DE 0.9 24 0.9 0 0 24 ** Boiler Fly Ash Silo ARGO: Removed 0.3 24 0.3 0 0 46 ** Ore Transfer Station ALL, ARGO: DE 0.71 24 0.71 0 0 50 ** "C" Train Dryer Area ALL, ARGO: DE 0.7 24 0.7 0 0 52 ** Product Silo - Top #2 BO-4, ARGO: DE 0.5 24 0.5 0 0 53 ** Product Silo - Bottom #2 BO-4, ARGO: DE 0.45 24 0.45 0 0 67 ** Bottom Ash Baghouse SAS-300, ARGO: Removed 0.47 24 0.47 0 0 76 ** "D" Train Primary Ore Screening ALL, ARGO: DE 2.45 24 2.45 0 0 79 ** Ore Transfer Point ALL, ARGO: DE 0.84 24 0.84 0 0 81 ** "D" Train Dryer Area BO-4, ARGO: DE 0.5 24 0.5 0 0 98 ** TPX Area SAS-300: DE 0.5 24 0.5 0 0 99 ** Crusher Baghouse #2 BO-4, ARGO: DE 3.2 24 3.2 0 0 100 ** Calciner Coal Bunker ALL, ARGO: Removed 0.2 24 0.2 0 0 103 ** East Ore Reclaim ALL, ARGO: DE 0.33 24 0.33 0 0 104 ** West Ore Reclaim ALL, ARGO: DE 0.27 24 0.27 0 0 105 ** S300 Dryer Baghouse SAS-300, ARGO: Removed 1.3 24 1.30 0 0 106 ** S300 Silo and Rail Loadout SAS-300, ARGO: Removed 0.1 24 0.10 0 0 * Note: There have been three PSD permit actions at the Solvay facility since 2010. BO-4 in 2013, SAS-300 in 2017, and the ARGO project here in 2019. Format above indicates if the source was part of one of these three projects / PSD permitting actions or ALL three of them. The right most note indicates that most recent permitting action for the source and either its source classification or if it was removed. Source classifications are as follows: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source, or E = Existing source (either contemporaneous to a PSD project or added to the facility since 2010, but not contemporaneous to particular PSD action). ** Due to particulate emissions from these sources being a function of baghouse airflow and design specifications (e.g., grain loading) and

not a function of production rates, these sources do not consume PM2.5 increment on a short-term basis since there is no actual change in emissions since the baseline date. *** These sources are conservatively modeled using an average daily actual emission rate (long-term) to represent a maximum actual daily emission rate. For example in 2010, source #17 operated 8,276 hours with reported PM emissions of 60.0 tpy (WDEQ annual reports). Thus, the average actual emission rate for 2010 for the source equals 14.5 lb/hr (60.0 tpy x 2000 lb/ton / 8,276 hr/yr = 14.5 lb/hr). **** During normal facility operating conditions, emergency generators are assumed to operate no more than 4 hours/day, max. lb/hr emissions are adjusted by 4/24 for modeling.

50 Table 6-11. Annual PM2.5 Increment Consuming Sources at the Solvay Facility

Allowable PSD Increment PSD Increment Annual PM PTE 2009/2010 Emissions; PTE - Emissions; PTE - WDEQ Operation Emissions Average Actual Baseline Actual Baseline Actual Source ID Source Description Note * (hr/yr) (tpy) Emissions (tpy) (tpy) (g/sec)

Project and Contemporaneous Sources Since Baseline Date Which Consume Annual PM2.5 Increment 110 ** "E" Train Dryer Area Baghouse ** ARGO: New 8,760 3.6 --- 3.6 0.1030 111 ** DR-8 Product Dryer ** ARGO: New 8,760 16.1 --- 16.1 0.4622 06B Product Silos - Bottom #1 BO-4, ARGO: DE 8,760 2.2 0.04 2.2 0.0630 07 Product Loadout Station BO-4, ARGO: DE 8,760 5.3 2.2 3.0 0.0866 10 Coal Crushing and Storage SAS-300, ARGO: Removed 8,760 0 *** 0.6 -0.6 0 11 Coal Transfer Station SAS-300, ARGO: Removed 8,760 0 *** 0.5 -0.5 0 14 Boiler Coal Boiler ARGO: Removed 8,760 0 *** 0.6 -0.6 0 15 DR-1 & 2 Steam Tube Dryers ALL, ARGO: DE 8,760 13.1 8.6 4.5 0.1296 16 Dryer Area BO-4, ARGO: DE 8,760 3.9 3.7 0.2 0.0065 17 "A" & "B" Calciners (converted to NG) ALL, ARGO: ME/DE 8,760 96.4 61.4 35.0 1.0061 18 #1 Boiler (converted to NG) ARGO: ME 8,760 12.6 10.1 2.5 0.0719 19 #2 Boiler (converted to NG) ARGO: ME 8,760 12.6 10.4 2.2 0.0645 48 "C" Calciner ALL, ARGO: DE 8,760 35.0 10.3 24.8 0.7123 50 "C" Train Dryer Area ALL, ARGO: DE 8,760 3.1 2.9 0.2 0.0053 51 Product Dryer #5 BO-4, ARGO: DE 8,760 10.5 3.7 6.8 0.1959 52 Product Silo - Top #2 BO-4, ARGO: DE 8,760 2.2 2.1 0.1 0.0021 53 Product Silo - Bottom #2 BO-4, ARGO: DE 8,760 2.0 0.8 1.2 0.0336 76 "D" Train Primary Ore Screening ALL, ARGO: DE 8,760 10.7 10.4 0.3 0.0088 79 Ore Transfer Point ALL, ARGO: DE 8,760 3.7 3.6 0.1 0.0030 * Note: There have been three PSD permit actions at the Solvay facility since 2010. BO-4 in 2013, SAS-300 in 2017, and the ARGO project here in 2019. Format above indicates if the source was part of one of these three projects / PSD permitting actions or ALL three of them. The right most note indicates that most recent permitting action for the source and either its source classification or if it was removed. Source classifications are as follows: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source, or E = Existing source (either contemporaneous to a PSD project or added to the facility since 2010, but not contemporaneous to particular PSD action). ** Modeled emissions for these sources are PTEs.

51 Table 6-11. Annual PM2.5 Increment Consuming Sources at the Solvay Facility (cont’d)

Allowable PSD Increment PSD Increment Annual PM PTE 2009/2010 Emissions; PTE - Emissions; PTE - WDEQ Operation Emissions Average Actual Baseline Actual Baseline Actual Source ID Source Description Note * (hr/yr) (tpy) Emissions (tpy) (tpy) (g/sec) 80 "D" Ore Calciner ALL, ARGO: ME/DE 8,760 43.8 32.0 11.8 0.3403 81 "D" Train Dryer Area BO-4, ARGO: DE 8,760 2.2 2.1 0.1 0.0032 82 DR-6 Product Dryer BO-4, ARGO: ME/DE 8,760 15.1 10.6 4.5 0.1308 98 TPX Area SAS-300: DE 8,760 2.2 0.4 1.8 0.0512 100 Calciner Coal Bunker ALL, ARGO: Removed 8,760 0 *** 0.2 -0.2 0 105 S300 Dryer Baghouse SAS-300, ARGO: Removed 8,760 0 *** 0.2 -0.2 0 106 S300 Silo and Rail Loadout SAS-300, ARGO: Removed 8,760 0 *** 0.001 -0.001 0 109 NG-fired Package Boiler ALL, ARGO: DE 8,760 8.3 --- 8.3 0.2381 EG3 ** Caterpillar 3456 (Emergency Shaft Generator) BO-4: E 500 0.2 --- 0.2 0.0043 EG4a ** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 500 0.1 --- 0.1 0.0014 EG4b ** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 500 0.1 --- 0.1 0.0014 EG4c ** Volvo TAD1353 GE (Main Shaft Emer. Gen.) BO-4: E 500 0.1 --- 0.1 0.0014 CH010 ** MikroPul 25S-10-20 Baghouse ARGO: E 8,760 0.9 --- 0.9 0.0252 EG5a ** Perkins Engine #1 (619 hp) Other: E 100 0.01 --- 0.01 0.0002 EG5b ** Perkins Engine #2 (619 hp) Other: E 100 0.01 --- 0.01 0.0002 EG5c ** Perkins Engine #3 (619 hp) Other: E 100 0.01 --- 0.01 0.0002

Project and Other Sources Since Baseline Date Which Do Not Consume Annual PM2.5 Increment 02A Ore Crusher Building #1 ARGO: E 8,760 7.0 7.0 0 0 06A Product Silos - Top #1 BO-4, ARGO: DE 8,760 1.3 1.3 0 0 24 Boiler Fly Ash Silo ARGO: Removed 8,760 1.3 1.3 0 0 46 Ore Transfer Station BO-4, ARGO: DE 8,760 3.1 3.1 0 0 67 Bottom Ash Baghouse SAS-300, ARGO: Removed 8,760 0 *** 2.1 -2.1 0 99 Crusher Baghouse #2 BO-4, ARGO: DE 8,760 14.0 14.0 0 0 103 East Ore Reclaim BO-4, ARGO: DE 8,760 1.4 1.4 0 0 104 West Ore Reclaim ALL, ARGO: Removed 8,760 1.2 1.2 0 0 * Note: There have been three PSD permit actions at the Solvay facility since 2010. BO-4 in 2013, SAS-300 in 2017, and the ARGO project here in 2019. Format above indicates if the source was part of one of these three projects / PSD permitting actions or ALL three of them. The right most note indicates the most recent permitting action for the source and either its source classification or if it was removed. Source classifications are as follows: New = New Project Source, ME = Modified Existing Source, DE = Debottlenecked Existing Source, or E = Existing source (either contemporaneous to a PSD project or added to the facility since 2010, but not contemporaneous to particular PSD action). ** Modeled emissions for these sources are PTEs.

52 6.4 Source Characterization for Modeling The source parameters for the sources at the facility are shown in Table 6-12. A close-up layout of the sources and buildings at the facility is shown in Figure 6-1. Since sources EG4a, EG4b, and EG4c have identical stack parameters and are located adjacent to each other, they were collocated for modeling purposes. Figure 6-2 shows the locations of all modeled sources with respect to the facility boundary. Corresponding source locations and source elevations above sea level utilized in the modeling analysis are provided in Table 6-13.

53 Table 6-12. Source Release Parameters – Solvay Facility

Exit Stack Height Temperature Exit Velocity Exit Diameter Source ID Source Description (ft) (m) ( F) ( K) (ft/s) (m/s) (ft) (m) 110 “E” Train Dryer Area Baghouse 120.0 36.6 249.5 394.0 52.9 16.11 2.83 0.86 111 DR-8 Product Dryer 180.0 54.9 350.6 450.2 47.4 14.46 8.00 2.44 17 "A" & "B" Calciners (converted to NG) 180.0 54.9 230.0 383.2 41.4 12.60 12.00 3.66 18 #1 Boiler (converted to NG) 180.0 54.9 400.0 477.6 69.4 21.14 7.30 2.21 19 #2 Boiler (converted to NG) 180.0 54.9 400.0 477.6 69.4 21.14 7.30 2.21 2A Ore Crusher Building #1 23.0 7.0 67.7 293.0 52.0 15.85 3.50 1.06 6A Product Silo - Top #1 133.0 40.5 96.5 309.0 82.0 24.99 2.10 0.64 6B Product Silo - Bottom #1 20.5 6.2 74.9 297.0 33.0 10.06 2.20 0.67 07 Product Loadout Station 82.0 25.0 67.7 293.0 64.0 19.51 2.50 0.75 15 DR-1 & 2 Steam Tube Dryers 180.0 54.9 164.9 347.0 49.0 14.94 6.00 1.83 16 Dryer Area 126.0 38.4 204.5 369.0 42.0 12.80 3.50 1.07 25 Alkaten Crushing 76.0 23.2 67.7 293.0 48.0 14.63 2.40 0.73 26 DR-3 Alkaten Product Dryer 67.0 20.4 100.1 311.0 58.0 17.68 2.40 0.73 27 Alkaten Product Bagging & Loadout 60.0 18.3 67.7 293.0 62.0 18.90 1.60 0.48 30 Lime Bin #1 88.0 26.8 67.7 293.0 59.0 17.98 0.70 0.20 31 Lime Bin #2 88.0 26.8 67.7 293.0 59.0 17.98 0.70 0.20 33 Sulfur Burner 100.0 30.5 150.0 338.7 34.5 10.52 2.00 0.61 35 Sulfite Dryer 103.0 31.4 128.9 327.0 48.0 14.63 2.30 0.70 36 Sulfite Product Bin #1 60.0 18.3 148.7 338.0 84.9 25.88 0.50 0.15 37 Sulfite Product Bin #2 60.0 18.3 148.7 338.0 84.9 25.88 0.50 0.15 38 Sulfite Product Bin #3 60.0 18.3 148.7 338.0 84.9 25.88 0.50 0.15 44 Lime Unloading 63.0 19.2 67.7 293.0 56.0 17.07 1.00 0.30 46 Ore Transfer Station 12.5 3.8 67.7 293.0 46.0 14.02 2.20 0.67 48 "C" Calciner 180.0 54.9 350.3 450.0 32.0 9.75 10.50 3.20 50 "C" Train Dryer Area 180.0 54.9 199.1 366.0 27.0 8.23 4.50 1.37 51 Product Dryer #5 180.0 54.9 299.9 422.0 33.0 10.06 8.00 2.44 52 Product Silo - Top #2 141.0 43.0 67.7 293.0 50.0 15.24 1.50 0.46 53 Product Silo - Bottom #2 30.0 9.1 67.7 293.0 36.0 10.97 2.80 0.85 54 T-200 Storage Bin 64.2 19.6 67.7 293.0 79.0 24.08 0.60 0.18 62 Carbon Bin 91.0 27.7 67.7 293.0 110.0 33.53 0.50 0.15 63 Perlite Bin 58.0 17.7 67.7 293.0 117.0 35.66 0.50 0.15 66 Carbon/Perlite 20.0 6.1 67.7 293.0 75.0 22.86 1.00 0.30 68 Trona Products Bagging Silo 82.0 25.0 67.7 293.0 77.0 23.47 1.20 0.37 70 Sodium Sulfite Bagging Silo 82.0 25.0 67.7 293.0 49.0 14.94 1.30 0.40 71 Metabisulfite Bagging Silo 82.0 25.0 67.7 293.0 49.0 14.94 1.30 0.40

54 Exit Stack Height Temperature Exit Velocity Exit Diameter Source ID Source Description (ft) (m) ( F) ( K) (ft/s) (m/s) (ft) (m) 72 MBS Soda Ash Feed Silo 60.7 18.49 199.1 366.0 53.0 16.15 0.70 0.20 73 Metabisulfite Dryer 95.0 29.0 89.3 305.0 56.0 17.07 2.00 0.61 76 "D" Train Primary Ore Screening 110.0 33.5 67.7 293.0 56.5 17.22 3.70 1.12 79 Ore Transfer Point 68.0 20.7 67.7 293.0 59.9 18.26 2.10 0.63 80 "D" Ore Calciner 180.0 54.9 305.3 425.0 50.8 15.49 10.50 3.20 81 "D" Train Dryer Area 120.0 36.6 249.5 394.0 76.4 23.29 1.70 0.51 82 DR-6 Product Dryer 180.0 54.9 298.1 421.0 43.1 13.15 8.00 2.44 88 Trona Products Transloading #2 11.0 3.4 67.7 293.0 64.0 19.51 1.00 0.30 88b Trona Products Transloading #3 11.0 3.4 68.0 293.2 63.7 19.40 1.00 0.30 92 Trona Products Bin #2 64.0 19.5 67.7 293.0 85.0 25.91 1.00 0.32 93 Trona Products Rail Loadout 70.0 21.3 67.7 293.0 53.0 16.15 1.00 0.30 94 Sulfite Loadout 90.0 27.4 67.7 293.0 85.0 25.91 1.00 0.32 95 Trona Products Loadout Bin 90.0 27.4 67.7 293.0 85.0 25.91 0.50 0.15 96 T-200 TPX Bin #1 82.0 25.0 67.7 293.0 72.0 21.94 0.80 0.25 97 Soda Ash TPX 82.0 25.0 67.7 293.0 72.0 21.94 0.70 0.20 98 TPX Area 82.0 25.0 67.7 293.0 56.0 17.07 1.50 0.46 99 Crusher Baghouse #2 125.0 38.1 67.7 293.0 50.0 15.24 4.50 1.37 101 Trona Products Dryer DR-7 120.0 36.6 120.0 322.0 64.0 19.51 3.30 0.99 102 Trona Products Loadout and Silo 120.0 36.6 68.0 293.0 59.0 17.98 1.80 0.53 103 East Ore Reclaim 38.0 11.6 68.0 293.0 91.0 27.74 1.10 0.33 104 West Ore Reclaim 64.0 19.5 68.0 293.0 50.0 15.24 1.30 0.40 105 S-300 Dryer #1 200.0 61.0 154.1 341.0 60.0 18.29 3.00 0.91 106 S-300 Silo and Rail Loadout #1 167.0 50.9 143.3 335.0 15.0 4.57 2.00 0.61 109 NG-fired Package Boiler 180.0 54.9 350.0 449.8 58.2 17.73 6.00 1.83 Waukesha F18GSI (GVBH E3 25.5 7.8 1116.0 875.4 45.6 13.90 1.17 0.36 compressor) E4 GM 8.1L (GVBH Pump) 10.8 3.3 1250.0 949.8 -- 10.00 * 0.24 0.07 E5 GM 4.3L (GVBH Pump) 10.8 3.3 1250.0 949.8 -- 10.00 * 0.24 0.07 MV ** Mine Vent 8.5 2.6 68.0 293.2 110.1 33.57 17.00 5.18 GVBH Fl GVB Flare (Gas Incinerator) 22.0 6.7 1800.0 1255.4 52.9 16.12 8.50 2.59 901 Cooling Tower - High Flow 15.0 4.6 Amb. 0.0 11.7 3.56 27.00 8.23 902 Cooling Tower - Low Flow 6.0 1.8 Amb. 0.0 11.7 3.56 18.00 5.49 Katolight SENL80FGC4 NG-Fired KATO 11.0 3.4 940.0 777.6 32.8 10.00 0.25 0.08 Generator CH010 MikroPul 25S-10-20 Baghouse 7.0 2.3 67.7 293.0 23.9 7.28 1.33 0.41 E7 GVBH Generator (88 hp GM 5.7L) 2.94 0.9 1403 1034.8 109.1 33.24 0.33 0.10 E8 GVBH Generator (88 hp GM 5.7L) 2.94 0.9 1403 1034.8 109.1 33.24 0.33 0.10 E9 Waukesha H24GSI Engine Compressor 12.57 3.8 1089 860.4 64.2 19.56 0.66 0.20

55 Exit Stack Height Temperature Exit Velocity Exit Diameter Source ID Source Description (ft) (m) ( F) ( K) (ft/s) (m/s) (ft) (m) Caterpillar 3456 (Emergency Shaft EG3 8.0 2.4 900.0 755.4 440.1 134.1 0.42 0.13 Generator) Volvo TAD1353 GE (Main Shaft EG4a 6.8 2.1 975.0 797.0 236.8 72.18 0.50 0.15 Emer. Gen.) Volvo TAD1353 GE (Main Shaft EG4b 6.8 2.1 975.0 797.0 236.8 72.18 0.50 0.15 Emer. Gen.) Volvo TAD1353 GE (Main Shaft EG4c 6.8 2.1 975.0 797.0 236.8 72.18 0.50 0.15 Emer. Gen.) FRP Emergency Fire Pump Engine 10.0 3.0 500.0 533.2 76.4 23.29 0.25 0.08 EG5a Perkins Engine #1 (619 HP) 8.7 2.7 1256 953.2 258.0 78.64 0.50 0.15 EG5b Perkins Engine #2 (619 HP) 8.7 2.7 1256 953.2 258.0 78.64 0.50 0.15 EG5c Perkins Engine #3 (619 HP) 8.7 2.7 1256 953.2 258.0 78.64 0.50 0.15 Volume Sy (m) Sz (m) Sources RAIL Rail Switching Engines*** 23.4 7.1 6.53 3.32

* Flow rate not known, assumed 10 m/s based on conservative combustion engine exhaust. ** Horizontal exhaust without downwash so POINTHOR option will be used. *** Mobile sources characterized as a series of volume sources, with each volume source having the parameters listed in the table.

56 Figure 6-1. Building and Source Layout at Solvay Facility

57 Figure 6-2. Source Layout at Solvay Facility – Including Mobile Source Locations

58 Table 6-13. Source Coordinates and Elevations

UTM Coordinates, NAD27, Zone 12 Source ID Source Description Easting Northing Elevation (meters) (meters) (ft) 110 "E" Train Dryer Area Baghouse 603852.0 4594876.0 6250 111 DR-8 Product Dryer 603861.5 4594888.3 6250 17 "A" & "B" Calciners (converted to NG) 603705.5 4594844.9 6250 18 #1 Boiler (converted to NG) 603861.3 4594835.2 6250 19 #2 Boiler (converted to NG) 603862.0 4594823.4 6250 2a Ore Crusher Building #1 603691.1 4595015.6 6237 6a Product Silo - Top #1 603925.9 4594839.2 6250 6b Product Silo - Bottom #1 603920.1 4594893.9 6250 7 Product Loadout Station 604052.8 4594878.5 6250 15 DR-1 & 2 Steam Tube Dryers 603740.6 4594844.2 6250 16 Dryer Area 603742.3 4594855.8 6250 25 Alkaten Crushing 603704.7 4595018.5 6237 26 DR-3 Alkaten Product Dryer 603683.0 4595004.7 6237 27 Alkaten Product Bagging & Loadout 603723.4 4595002.2 6237 30 Lime Bin #1 603957.1 4594798.5 6257 31 Lime Bin #2 603957.5 4594776.0 6257 33 Sulfur Burner 603915.2 4594760.7 6257 35 Sulfite Dryer 603950.9 4594752.4 6257 36 Sulfite Product Bin #1 603977.2 4594751.0 6257 37 Sulfite Product Bin #2 603997.6 4594751.5 6257 38 Sulfite Product Bin #3 603981.2 4594728.8 6257 44 Lime Unloading 604031.1 4594788.7 6257 46 Ore Transfer Station 603779.2 4595027.4 6237 48 "C" Calciner 603704.5 4594884.5 6250 50 "C" Train Dryer Area 603733.7 4594886.2 6250 51 Product Dryer #5 603758.3 4594868.8 6250 52 Product Silo - Top #2 603919.2 4594919.6 6250 53 Product Silo - Bottom #2 603942.2 4594884.0 6250 54 T-200 Storage Bin 603712.2 4594997.3 6237 62 Carbon Bin 603636.5 4594765.5 6250 63 Perlite Bin 603636.1 4594754.2 6250 66 Carbon/Perlite 603725.6 4594802.9 6250 68 Trona Products Bagging Silo 603952.9 4594855.5 6250 70 Sodium Sulfite Bagging Silo 603952.8 4594866.6 6250 71 Metabisulfite Bagging Silo 603967.7 4594864.7 6250 72 MBS Soda Ash Feed Silo 603931.1 4594749.5 6257 73 Metabisulfite Dryer 603915.7 4594748.7 6257 76 "D" Train Primary Ore Screening 603605.1 4594993.4 6237 79 Ore Transfer Point 603504.5 4594997.0 6237 80 "D" Ore Calciner 603681.2 4594905.7 6250 81 "D" Train Dryer Area 603793.1 4594875.0 6250 82 DR-6 Product Dryer 603765.3 4594869.0 6250 88 Trona Products Transloading #2 604050.8 4594956.7 6250 88b Trona Products Transloading #3 604050.8 4594937.2 6257 92 Trona Products Bin #2 603995.6 4594730.6 6257 93 Trona Products Rail Loadout 604012.1 4594765.1 6257 94 Sulfite Loadout 604011.9 4594753.3 6257 95 Trona Products Loadout Bin 604012.7 4594742.6 6257 96 T-200 TPX Bin #1 603963.2 4594762.0 6257 97 Soda Ash TPX 603960.1 4594765.6 6257

59 Table 6-13. Source Coordinates and Elevations (cont’d)

UTM Coordinates, NAD27, Zone 12 Easting Northing Elevation Source ID Source Description (meters) (meters) (ft) 98 TPX Area 603960.2 4594771.0 6257 99 Crusher Baghouse #2 603666.3 4595020.3 6237 101 Trona Products Dryer DR-7 603695.6 4595000.6 6237 102 Trona Products Loadout and Silo 604052.7 4594891.5 6250 103 East Ore Reclaim 603761.2 4595006.2 6237 104 West Ore Reclaim 603621.8 4595020.5 6237 105 S-300 Dryer #1 603949.3 4594741.4 6257 106 S-300 Silo and Rail Loadout #1 604058.3 4594747.7 6257 109 NG-fired Package Boiler 603828.2 4594847.8 6250 E3 Waukesha F18GSI (GVBH compressor) 606566.8 4591548.1 6352 E4 GM 8.1L (GVBH Pump) 606403.3 4591421.8 6352 E5 GM 4.3L (GVBH Pump) 606700.5 4592001.3 6440 MV Mine Vent 603344.3 4594881.3 6247 GVBFL GVB Flare (Gas Incinerator) 606393.3 4591411.8 6309 901 Cooling Tower - High Flow 603864.0 4594781.9 6257 902 Cooling Tower - Low Flow 603866.7 4594750.9 6257 KATO Katolight SENL80FGC4 NG-fired Generator 606566.8 4591548.1 6352 CH010 MikroPul 25S-10-20 Baghouse 603913.1 4594722.3 6257 E7 GVBH Generator (88 hp GM 5.7L) 606566.8 4591548.1 6352 E8 GVBH Generator (88 hp GM 5.7L) 606566.8 4591548.1 6352 E9 Waukesha H24GSI Engine - Compressor 606566.8 4591548.1 6352 EG3 Caterpillar 3456 (Emergency Shaft Generator) 603325.3 4594816.0 6253 EG4 Volvo TAD1353 GE (Main Shaft Emer. Gen.) 603499.0 4594949.7 6237 EG4 Volvo TAD1353 GE (Main Shaft Emer. Gen.) 603499.0 4594949.7 6237 EG4 Volvo TAD1353 GE (Main Shaft Emer. Gen.) 603499.0 4594949.7 6237 FRP Emergency Fire Pump Engine 603806.5 4594743.7 6257 EG5a Perkins Engine #1 (619 HP) 603765.2 4594766.5 6257 EG5b Perkins Engine #2 (619 HP) 603765.5 4594760.2 6257 EG5c Perkins Engine #3 (619 HP) 603765.9 4594753.9 6257 Volume Sources Line of volumes (RR001 through RR532); no. of RAIL Rail Switching Engines volumes varies based on SIA distance; see modeling files.

60 6.5 Modeling Methodology In general, AERMOD was run for the facility, and competing sources (as needed), and the impacts were added to the background concentration for comparison to the WAAQS and NAAQS. For the PSD increment analyses, impacts (without background) were compared to the PSD increments.

6.5.1 Model Selection Per Solvay’s approved modeling protocol, the most recent version (18081) of the AERMOD (AMS/EPA

Regulatory Model) was used to estimate the air quality impacts from the Solvay project PM10, PM2.5, and CO emissions. AERMOD is an advanced modeling system that incorporates the boundary layer theory, turbulence, and effects of terrain features into air dispersion simulations. It is the EPA-recommended guideline model for this type of facility and terrain.

The 18081 version of AERMOD contains PRIME (Plume Rise Model Enhancements) algorithms for downwash calculations. The most recent version of the Building Profile Input Program (BPIP) with PRIME (BPIPPRM, version 04274) was used to calculate building downwash parameters for input to AERMOD.

AERMOD was run using the regulatory default options.

6.5.2 Meteorological Data Per Solvay’s approved modeling protocol, three years (2009–2011) of on-site hourly surface meteorological data from Solvay's 30-meter tower was used as the basis for the meteorological data.

6.5.3 Receptor Grid AERMOD requires receptor terrain processing with the AERMAP pre-processor (version 18081) to extract receptor elevations and estimate hill height scale values. AERMAP uses United States Geological Survey 1-degree and 7.5-minute Digital Elevation Model (DEM) files and National Elevation Dataset (NED) input for this purpose. AERMAP was run to generate the receptor elevations and hill heights using the NED data.

The following receptor grid spacing was used in the modeling analyses:

 50-meter spacing along the facility’s modeling boundary,

 100-meter spacing between the modeling boundary and 3 kilometers from the facility,

 500-meter spacing between 3 kilometers and 10 kilometers from the facility, and

 1,000-meter spacing out beyond 10 kilometers as needed to capture the full extent of the SIA, with a maximum distance of 50 kilometers.

61 The modeling boundary follows the WDEQ-approved Plant Works Boundary for the Solvay facility for air permitting actions at the facility. This same boundary was utilized for the previously approved BO-4 PSD permit modeling in 2013. The boundary has been established to identify the areas where public access is restricted and is denoted by postings to inform the public at key locations. The Solvay facility is located in an isolated, rural location away from any nearby population center. The only main access road to the facility is County Road 85 to the west of the facility. The nearest residence to the facility is located approximately 4.1 miles to the east. The nearest population center is Little America, Wyoming (population less than 100 people) located approximately 5.8 miles to the northwest.

Figure 6-3 provides an overview of the receptor grid used for the impact analysis.

62 Figure 6-3. Overview of Receptor Grid Used in the Impact Analysis

63

6.5.4 Background Concentrations Table 6-14 shows the background levels utilized for the project. The background values are based on the average of the yearly high or 98th percentile value from 2015 to 2017. Stations used were located near Old

Faithful Lodge in Yellowstone NP for CO and Rock Springs for PM2.5.

Table 6-14. Background Values Utilized in Impact Analysis

Pollutant Averaging Monitored Concentration Proposed Description Period 2015 2016 2017 Background Concentration Three-year average of maximum 1-hour CO 0.8 0.7 0.7 0.7 measured value from Yellowstone (ppm) NP, Old Faithful Lodge 8-hour Three-year average of maximum CO (ppm) 0.4 0.4 0.7 0.5 measured value from Yellowstone NP, Old Faithful Lodge Three-year average of the 98th 24-hour PM2.5 15.5 13.0 20.5 16.3 percentile values measured from (g/m3) Rock Springs (avg. of two monitors) Annual Three-year annual average from PM2.5 4.8 5.0 5.6 5.1 (g/m3) Rock Springs (avg. of two monitors) Sources: EPA AirData Database: https://www.epa.gov/outdoor-air-quality-data/monitor-values-report

64 6.5.5 Secondary PM2.5 Formation This section describes an evaluation of impacts of secondary fine particulatte matter with aerodynamic diameters less than 2.5 microns (PM2.5) for the Solvay facility and the ARGO project.

6.5.5.1 Regulatory Background On Januaryr 17, 2017, EPA promulgaated an update to its Guideline on Air Quality Models (GAQM) in 40 CFR 51, Appendix W, to incorporate a tiered demonstration approach to address the secondary chemical formation of O3 and PM2.5 associated with precursor emissions from single sources (such as the Solvaay facility). This new GAQM rule (which updated a 2005 version of the GAQM) became effective February 16, 2017. According to EPA, for all regulatory applications covered under the GAQM, the revisions to the requirements and recommendations of the GAQM must be integrated into the regulatory processes of respective reviewing authorities, and followed by applicants bby no later than January 17, 2018.

EPA’s GAQM update finalized a two-tiered approach for addressing single-source O3 and secondary

PM2.5 impacts:

 Tier 1: The first tier of assessment involves those situations where existing technical information is available (e.g., results from existing photochemical grid modelinng [PGM], published empirical estimates of source-specific impacts, or reduced-form models) in combination with other supportive information and analysis for the purposes of estimating secondary impacts from a particular source. According to EPA, the existing technical information should provide a credible and representative estimate of the secondary impacts from the prooject source.

 Tier 2: If the first-tier analyssis is not suitable, then a second-tier annalysis would be accomplished, which involves the application of more sophisticated, case-specific air quality modeling anallyses using chemical transport models.

EPA’s expectation is that the first-tier analysis should be appropriate for most permit applicants; the second tier may only be necessary in special situations.

In addition to the 2017 GAQM updates, EPA issued single-source O3 and secondary PM2.5 guidance on December 2, 20166 and this guidance was updated again on April 30, 20197. This guidance provides information for the development of modeled emission rates for precursorss (MERPs) as a Tier 1 demonstration tool for O3 or secondary PM2.5. MERPs are maximum emission rates of precursors that would not be expected to exceed significant impact levels (e.g., 1 part per billion [ppb] for O3), and thus would not cause or contribute to air quality violations for these pollutants. The EPA guidance document includes PGM output concentrations for O3 and secondary PM2.5 information from a varriety of hypothetical modeled sources that can be used to estimate impacts of secondary PM2.5 and O3.

6 EPA. Guidance on the Development of Modeled Emission Rates for Precursors (MERPs) as a Tier I Demonstration Tool for Ozone and PM2.5 Under the PSD Permitting Program. December 2, 2016. 7 EPA. Guidance on the Development of Modeled Emission Rates for Precursors (MERPs) as a Tier I Demonstration Tool for Ozone and PM2.5 Under the PSD Permitting Program. April 30, 2019.

65 According to EPA’s guuidance, for Tier 1 assessments, EPA generally expeccts that applicants would use existing empirical relationships between precursors and secondary impacts based on modeling systems appropriate for this purpose. Examples of existingn relevant tecchnical information include the following:

 Air quality modeling conducted for the relevant geographic area reflecting emissions changees for similar source types as part of a State Implementation Plan (SIP) demonstration, other permit action, or similar policy assessment

 Air quality modeling of hyppothetical industrial sources that have similar source characteristics and emission rates of precursors and that are located in similar atmospheric environments, and

for time periods that are conducive to the formation of O3 or secondary PM2.5

Where the existing technical information is based on chemical and physical conditions that are less similar to the project source and key receptors, a more conservative estimate of impacts using demonstration tools may be necessary.

6.5.5.2 Assessment of Secondary PM2.5 Impacts from Solvay Fine particulate matter emissions from combustion sources consist of three constituents: primary particulates, condensable particulates, and secondary particles. The primarry/direct particulates are the fraction of PM2.5 emissions that originates as particles (e.g., sooot) and are immediately filterable. This is referred to as the “front-half” in a PM2.5 sampling methodologgy. The condensable particulates originate in the gaseous chemicals that condense in the exhaust to form particles after exposure to the cooler temperatures of the atmosphere. This is referred to as the “back-half” in a particulate sampling methodology. Finally, secondary particles are formed when exhaust gases, most notably NOX and SO2, from the stack interact with other chemical species in the downwind atmosphere to form fine particles.

Direct PM2.5 impacts for the ARGO project are modeled using EPA’s AERMOD dispersion model. To evaluate secondary PM2.5 impacts, Solvay has performed a Tier 1 assessment for the ARGO Project using EPA’s MERPs guidance document, which includes EPA’s hyppothetical source PGM output concentrations. Solvay relates impacts from EPA’s hypotheticcal sources to the Solvay facility to estimate secondary PM2.5 impacts.

EPA’s MERPs guidance document includes EPA’s hypotheticcal source PGM output concentrations for various locations across the United States (U.S.), including various locations in the western U.S.

Figure 6-4 provides the modeling domain and hypothetical source locations for EPA’s western U.S. modeling domain. EPA’s hypothetical source numbers are provided in the figure.

Per EPA’s December 2, 2016 MERPs guidance, EPA source #12 is the nearest hypothetical source to the Solvay facility and is located 86 miles southwest of Solvay. As presented in Solvay’s April 4, 2019 modeling protocol, WDEQ approved the use of data from this hypothetical source to assess secondarry

PM2.5 impacts from the Solvay facility. Source #12 is located in rural northeastern Utah, away from the influence of urban/metropolitan area precursor emissions, and is representative of Solvay’s rural

66 location. Per EPA’s April 30, 2019 MERPs guidance, EPA also included PGM data from an additional hypothetical source (#34) located in southwest Wyoming approximately 40 miles to the northwest of the Solvay facility. Data from these hypothetical source locations are discussed below.

67 Figure 6-4. EPA’s PGM Modeling Domain and Hypothetical Source Locations – Western U.S.

68 Table 6-15 presents Solvay’s PM2.5 precursor emissions (NOx and SO2) for various considerations (entire facility for a NAAQS analysis and increment consuming sources for a PM2.5 PSD increment analysis).

Note that the ARGO project modification itself results in a substantial decrease in PM2.5 precursor emissions (i.e., 615 tpy reduction of NOx and 44 tpy reduction of SO2). Therefore, to be conservative, the

SIA analysis considers direct PM2.5 emissions, but does not include any reduction in secondary PM2.5 formation from the decrease in precursor emissions.

For the NAAQS and PSD increment analyses, secondary PM2.5 impacts are estimated by interpolation between the impacts from EPA’s PGM. Solvay’s NOx and SO2 emissions are compared to emissions of EPA’s PGM hypothetical sources to determine the emission scenarios that most closely match Solvay’s emissions. A linear relationship between those scenarios’ emissions and secondary PM2.5 impacts was determined and assessed at Solvay’s NOx and SO2 emission rates. The contribution of NOx and SO2 emissions to secondary PM2.5 formation are added together to determine a total secondary PM2.5 value. For example, for the NAAQS analysis (using full facility PTE emissions), Solvay’s maximum daily and maximum annual secondary PM2.5 concentrations (contribution from NOx + contribution from SO2) were 3 3 found to be 0.043 g/m and 0.002 g/m , respectively.

Table 6-16 and Table 6-17 demonstrate that Solvay’s expected contribution to secondary PM2.5 formation is negligible. The first set of tables (“a”) utilize EPA hypothetical source #12 data and the second set of tables (“b”) utilize EPA hypothetical source #34 data. The PGM output data for sources #12 and #34 are very similar and do not affect overall conclusions of the analyses.

69 Table 6-15. Solvay PM2.5 Precursor Emissions

Is Source Part Does Source Maximum Allowable Emissions WDEQ Source of the ARGO Consume Increment Operations NOx SO2 ID Source Description Modification? for Direct PM2.5? (hr/yr) (lb/hr) (tpy) (lb/hr) (tpy) 111 New DR-8 Product Dryer Yes Yes 8760 30.00 131.4 0.1 0.5 17 "A" and "B" Calciners (converted to NG) Yes Yes 8760 14.40 63.1 18 #1 Boiler (converted to NG) Yes Yes 8760 9.3 40.7 0.2 1.0 19 #2 Boiler (converted to NG) Yes Yes 8760 9.3 40.7 0.2 1.0 48 "C" Calciner Yes Yes 8760 15.00 65.7 51 Product Dryer #5 Yes Yes 8760 18.00 78.8 0.1 0.4 80 "D" Ore Calciner Yes Yes 8760 20.00 87.6 82 DR-6 Product Dryer Yes Yes 8760 30.00 131.4 0.1 0.5 109 NG-fired Package Boiler Yes Yes 8760 2.8 12.3 0.15 0.7 26 DR-3 Alkaten Product Dryer No No 8760 0.25 1.1 33 Sulfur Burner No No 8760 0.3 1.3 0.4 1.8 73 Metabisulfite Dryer No No 8760 0.25 1.1 0.77 3.4 101 Trona Products Dryer DR-7 No No 8760 0.5 2.4 E3 Waukesha F18GSI (GVBH compressor) No No 8760 0.6 2.6 E4 GM 8.2L (GVBH Pump) No No 8760 0.3 1.3 E5 GM 4.3L (GVBH Pump) No No 8760 0.2 0.9 GVBH Fl GVB Flare (Gas Incinerator) No No 8760 5.9 25.7 KATO Katolight SENL80FGC4 NG-fired Generator No No 8760 0.3 1.3 E7 GVBH Generator (88 hp GM 5.7L) No No 8760 0.1 0.4 E8 GVBH Generator (88 hp GM 5.7L) No No 8760 0.1 0.4 E9 Waukesha H24GSI Engine - Compressor No No 8760 0.8 3.5 EG-3 Caterpillar 3456 (Emergency Shaft Generator) No Yes 500 10.5 2.6 0.3 0.1 EG-4a Volvo TAD1353 GE (Main Shaft Emer. Gen.) No Yes 500 4.0 1.0 0.2 0.1 EG-4b Volvo TAD1353 GE (Main Shaft Emer. Gen.) No Yes 500 4.0 1.0 0.2 0.1 EG-4c Volvo TAD1353 GE (Main Shaft Emer. Gen.) No Yes 500 4.0 1.0 0.2 0.1 FRP Emergency Fire Pump Engine No No 500 9.0 2.2 0.6 0.1 EG-5a Perkins Engine #1 (619 HP) No Yes 100 3.93 0.2 EG-5b Perkins Engine #2 (619 HP) No Yes 100 3.93 0.2 EG-5c Perkins Engine #3 (619 HP) No Yes 100 3.93 0.2 Solvay Facility Totals (Post-ARGO Modification) > ‐‐‐ --- 702.2 --- 9.6

PM2.5 Precursor Emissions for Sources That Consume PM2.5 Increment > ‐‐‐ --- 657.9 --- 4.3

70 Table 6-16. Solvay Secondary PM2.5 Impacts – 24-hour Average

a. Using EPA PGM Source #12 Data

Solvay Solvay

Parameter EPA PGM Value * NAAQS PM2.5 Increment NOx Emissions (tpy) 500 1,000 702 658

3 Secondary PM2.5 from NOx Precursors (g/m ) 0.03 0.06 0.042 0.039

SO2 Emissions (tpy) 0 500 10 4

3 Secondary PM2.5 from SO2 Precursors (g/m ) 0 0.07 0.001 0.001

Total 24-hour Secondary PM from NOx and SO 2.5 2 ------0.043 0.040 Precursors (g/m3)

* Based on EPA PGM, Source #12.

b. Using EPA PGM Source #34 Data

Solvay Solvay

Parameter EPA PGM Value * NAAQS PM2.5 Increment NOx Emissions (tpy) 500 1,000 702 658

3 Secondary PM2.5 from NOx Precursors (g/m ) 0.03 0.06 0.042 0.039

SO2 Emissions (tpy) 0 500 10 4

3 Secondary PM2.5 from SO2 Precursors (g/m ) 0 0.05 0.001 0.0005

Total 24-hour Secondary PM from NOx and SO 2.5 2 ------0.043 0.040 Precursors (g/m3)

* Based on EPA PGM, Source #34.

71 Table 6-17. Solvay Secondary PM2.5 Impacts – Annual Average

a. Using EPA PGM Source #12 Data

Solvay Solvay

Parameter EPA PGM Value * NAAQS PM2.5 Increment NOx Emissions (tpy) 500 1,000 702 658 3 Secondary PM2.5 from NOx Precursors (g/m ) 0.001 0.002 0.0014 0.0013

SO2 Emissions (tpy) 0 500 10 4

3 Secondary PM2.5 from SO2 Precursors (g/m ) 0 0.004 0.0001 0.00003

Total Annual Secondary PM2.5 from NOx and 3 ------0.0015 0.0014 SO2 Precursors (g/m )

* Based on EPA PGM, Source #12.

b. Using EPA PGM Source #34 Data

Solvay Solvay

Parameter EPA PGM Value * NAAQS PM2.5 Increment NOx Emissions (tpy) 500 1,000 702 658

3 Secondary PM2.5 from NOx Precursors (g/m ) 0.002 0.003 0.0021 0.0020

SO2 Emissions (tpy) 0 500 10 4

3 Secondary PM2.5 from SO2 Precursors (g/m ) 0 0.002 0.00003 0.00001

Total Annual Secondary PM2.5 from NOx and 3 ------0.0022 0.0020 SO2 Precursors (g/m )

* Based on EPA PGM, Source #34.

72 6.6 Nearby/Competing Sources If the pollutant impact exceeded the SIL, a full impact analysis was conducted, which included impacts from nearby sources. The ARGO project has significant impacts for PM2.5 and CO and a full impacts analysis, including competing sources, was required.

The competing sources were included in the impact analysis for all pollutants and averaging times that exceeded the SIL. Only receptors within the SIA were evaluated. Table 6-18 provides a summary of the competing source facilities and emissions considered in the full impact analyses. Note that for CO, consistent with the modeling approach for the BO-4 PSD project in 2013, emissions information for the four nearby competing trona facilities (Tata Chemicals, Genesis Alkali Westvaco, Genesis Alkali Granger, and Ciner Big Island) were obtained from the Title V permits for each of the facilities. To be conservative, the CO emissions from these facilities were modeled assuming that all CO facility emissions were emitted from the shortest smokestack at each facility.

Table 6-18. Competing Sources for Inclusion in Full NAAQS Analysis

PM2.5 Emissions CO Emissions Facility (tpy) (tpy) * TATA Chemicals (Soda Ash) Partners - Green River Works 1,645 ** 536 Ciner Wyoming LLC - Big Island Mine & Refinery 1,129 ** 5,731 Genesis Alkali Wyoming, LP - Westvaco Facility 1,438 *** 473 Genesis Alkali Wyoming, LP - Granger Soda Ash Facility 158 *** 604 Church and Dwight - Green River Facility 179 ** --- Harborlite - Green River Perlite Ore Processing 12 ** ---

* Obtained from the latest Title V permits on Wyoming's Air Quality IMPACT webpage (accessed 03/19/2019): https://openair.wyo.gov/disclaimer.jsf ** Conservatively modeled as PM emissions; previously used in Solvay's BO-4 PSD modeling in 2013. *** From FMC Wyoming Corporation - Granger Facility, WDEQ Permit Application Analysis (AP-12487) and AERMOD modeling files.

73 6.7 Modeling Results 6.7.1 Preliminary Analysis Results Initially, the SIA is determined for every relevant averaging time for a particular pollutant as shown in Table 6-19. The final SIA for that pollutant is the largest area for each of the various averaging times. According to the EPA’s Draft New Source Review Workshop Manual (EPA, 1990), the SIA is a circular area with a radius extending from the source to: 1) the most distant point where approved dispersion modeling predicts a significant ambient impact will occur, or 2) a modeling receptor distance of 50 kilometers, whichever is less. Therefore, a SIA cannot be greater than 50 kilometers for any pollutant.

AERMOD was run for the ARGO project (new sources, existing modified sources, debottlenecked sources) and contemporaneous sources (as identified in Table 6-2) for each pollutant and averaging time for the SIA analyses.

Table 6-19 provides the Class II SIAs from the ARGO project and indicates SIAs of 3.8 km for PM2.5 and

2.3 km for CO. Impacts of PM10 are not significant and no further modeling of PM10 is required. The results of the full impact modeling analyses utilizing these SIAs are provided in Section 6.7.2.

74 Table 6-19. Class II Significant Impact Areas for ARGO Project

Averaging Max. Modeled Class II SIL Significant SIA Distance Pollutant Period Impact (g/m3) (g/m3) Impact? (km) 1

Fine Particulate Matter (PM2.5) 24-hour 2 1.7 1.2 Yes 1.2 Annual 2 0.6 0.3 Yes 3.8 3 Particulate Matter (PM10) 24-hour 2.5 5 No Not Sig. Annual 3 0.6 1 No Not Sig. Carbon Monoxide (CO) 1-hour 3 3,187 2,000 Yes 2.0 8-hour 3 1,013 500 Yes 2.3

1 Measured from Source #17.

2 For PM2.5, the average of the maximum modeled impacts averaged over three years on a receptor-by-receptor basis is utilized to determine the SIA. 3 For these pollutants and averaging periods, the maximum modeled concentrations are used to determine the SIAs.

75 6.7.2 Full Impact Modeling Results A summary of the maximum modeled impacts from the Solvay facility for comparison to the WAAQS/NAAQS and PSD increments are provided in Table 6-20 and Table 6-21. These results show that the Solvay facility and its proposed ARGO project will comply with these ambient standards.

Note that all maximum NAAQS and increment impacts are located close to the Solvay facility on the modeling boundary or very close to the modeling boundary as shown in Figure 6-5.

The AERMOD and BPIP model input and output files, meteorological data files, and other related electronic file documentation will be provided to WDEQ.

76 Table 6-20. Summary of Maximum Modeled Impacts – NAAQS/WAAQS Analysis

NAAQS/ Exceed Averaging Max. Impact Receptor 1 Concentration (g/m3) WAAQS NAAQS/

Pollutant Period UTM_Easting (m) UTM_Northing (m) Modeled Background Total (g/m3) WAAQS?

2 Fine Particulate Matter (PM2.5) 24-hour 603,609.5 4,595,774.7 10.1 16.3 26.4 35 No Annual 4 606,000.0 4,594,550.8 3.3 5.1 8.4 12 No Carbon Monoxide (CO) 1-hour 3 603,869.4 4,595,924.6 3,807 801.5 4,609 40,000 No 8-hour 3 603,999.3 4,595,999.6 1,007 572.5 1,580 10,000 No

1 UTM, NAD27, Zone 12 coordinates. 2 Three-year average of the highest-eighth-highest max. daily modeled concentrations on a receptor-by-receptor basis. 3 Highest-second-highest modeled concentrations. 4 Three-year average of the annual modeled concentrations on a receptor-by-receptor basis.

77 Table 6-21. Summary of Maximum Modeled Impacts – PSD Increment Analysis

Max. Modeled Impact PSD Class II Averaging Max. Impact Receptor 2 without Background Increment Exceed

Pollutant Period UTM_Easting (m) UTM_Northing (m) Concentration (g/m3) (g/m3) Increment?

Fine Particulate Matter (PM2.5) 24-hour 1 603,500.0 4,595,800.0 2.2 9 No Annual 606,000.0 4,594,550.8 0.7 4 No

1 Presented as the highest-second-highest value, consistent with 40 CFR 52.21(c) for impact comparisons to the short-term PSD increments. 2 UTM, NAD27, Zone 12 coordinates.

78 Figure 6-5. Map of Locations of Maximum Modeled Impacts from NAAQS and PSD Increment Analyses

79 7.0 AIR QUALITY IMPACT EVALUATION – CLASS I AREAS

7.1 Class I Areas with Respect to Solvay Facility The U.S. Congress established certain areas, e.g., wilderness areas and national parks (NP), as mandatory Class I areas. Procedures exist under the PSD regulations to redesignate the Class II areas to either Class I or Class III, depending upon a state's land management objectives. Althouugh it is not one of the 156 Federal Class I areas, the State of WyW oming has declared that the Savage Run Wilderness area must be managed as a Class I area.

Figure 7-1 shows the location of the Class I areas with respectt to the Solvay facility. All Class I areas are located grreater than 50 kilometers (km) from the Solvay facilitty. Table 7-1 lists each Class I area, the managing agency (the U.S. Forest Service (USFS), under the Department of Agriculture (USDA), the National Park Service (NPS), or the State of Wyoming), and the distance from the Solvaay facility to each Class I area.

Figure 7-1. Location of Class I Areas within 300 Kilometers of the Solvay Facility

80 Table 7-1. Class I Areas Located within 300 Kilometers of Solvay

Distance Class I Area Agency (km) Bridger Wilderness USFS 131 Fitzpatrick Wilderness USFS 167 Grand Teton National Park NPS 240 Washakie Wilderness USFS 245 Teton Wilderness USFS 251 Mt. Zirkel Wilderness USFS 251 Flat Tops Wilderness USFS 255 Savage Run Wilderness Wyoming 277 Yellowstone National Park NPS 293 Arches National Park NPS 295

7.2 Class I Area Air Quality Related Values (AQRV) Analysis Under the Clean Air Act, the Federal Land Manager (FLM) and the federal official with direct responsibility for management of Federal Class I parks and wilderness areas (i.e., Park Superintendent, Refuge Manager, Forest Supervisor) have an affirmative responsibility to protect the air quality related values (AQRVs) (including visibility, ozone, deposition) of such lands, and to consider whether a proposed major emitting facility will have an adverse impact on such values. To address this concern, the FLMs formed the Federal Land Managers’ Air Quality Related Values Work Group (FLAG). As outlined in the Federal Land Managers’ Air Quality Related Values Work Group (FLAG) Phase I Report - Revised (2010)8, an Initial Screening Criteria analysis was established by FLAG to determine whether or not it is necessary to perform AQRV analysis at Class I areas as part of a PSD permitting process for a facility. This analysis considers the magnitude of emissions from a proposed project and the distance from the proposed project to surrounding Class I areas.

For the ARGO project, Solvay provided a technical summary of a Class I Area FLAG Initial Screening Criteria analysis (dated March 6, 2019) for the ARGO project to WDEQ for FLM review prior to the submittal of an impact modeling protocol and PSD permit application to WDEQ. In the analysis, Solvay concluded that it was not necessary to evaluate AQRVs at the Class I areas surrounding the facility. A copy of the Solvay’s Class I Area FLAG Initial Screening Criteria analysis is provided as Appendix F. Solvay’s Class I Area FLAG Initial Screening Criteria analyses did not require Solvay to perform further AQRV analyses, but it was still necessary to evaluate Class I PSD increments not exempted from the FLAG screening analysis. A Class I PSD increment analysis for the ARGO project is provided in Section 7.3.

8 Natural Resource Report NPS/NRPC/NRR—2010/232; http://www.nature.nps.gov/air/Pubs/pdf/flag/FLAG_2010.pdf1

81 7.3 Class I PSD Increment Analysis Table 7-2 shows the Class I PSD increments and their associated SILs.

Table 7-2. Class I PSD Increments and SILs

Class I PSD Averaging Increment Class I SIL Criteria Pollutant Time (g/m3 ) (g/m3)

PM10 24-hour 8 0.3 Annual 4 0.2

PM2.5 24-hour 2 0.07 Annual 1 0.06

Following the same, previously approved approach for the BO-4 PSD project in 2013, in order to make a conservative concentration estimate, AERMOD was run with receptors placed at a distance of 50 km from the facility. The receptors were set at the lowest, middle level, and highest elevation for all of the Class I areas within 300 kilometers of the Solvay facility. The resultant concentrations were compared to the Class I SILs and are shown in Table 7-3. Modeling demonstrates that the emissions from the Solvay ARGO project are less than the significant impact levels at the Class I areas and that a cumulative PSD increment analysis (i.e., full analysis) is not required. This Class I SIA modeling demonstrates that the project would not threaten any Class I PSD increment at any Class I area, the nearest of which is an additional 81 kilometers from the most distant receptor used in the analysis.

Table 7-3. Summary of Maximum Modeled Impacts Compared to Class I Area SILs

Max. Modeled Class I SIL Significant Criteria Pollutant Averaging Time Impact (g/m3) (g/m3) Impact?

24-hour 0.06 0.3 No PM10 Annual 0.01 0.2 No 24-hour 0.05 0.07 No PM2.5 * Annual 0.01 0.06 No * Probabilistic standard; three-year average of the maximum modeled values on a receptor-by-receptor basis.

82 8.0 PSD ADDITIONAL IMPACTS ANALYSIS

The PSD additional impacts analysis generally has three parts: growth, soil and vegetation impacts, and visibility impairment. According to WAQSR, Chapter 6, Section 4(b)(i)(B)(I), for the PSD additional impact analyses, the owner or operator shall provide an analysis of the impairment to visibility, soils and vegetation that would occur as a result of the source or modification and general commercial, residential, industrial, and other growth associated with the source or modification. The owner or operator need not provide an analysis of the impact on vegetation having no significant commercial or recreational value. The growth, soil and vegetation impacts, and visibility impairment analysis approaches presented here were also utilized for the BO-4 PSD project approved by WDEQ in 2013.

8.1 Growth Analysis For the growth analysis, an estimate of the amount of possible growth is made. As the facility is an existing facility, the growth associated with the boiler project is likely to be minor because no new work shifts will be added. The construction of the project may result in a small temporary increase in the local population during the construction period for the project, but would not result in a significant population shift or increase. Therefore, additional air quality impacts from growth as are result are not expected.

8.2 Soil and Vegetation Impacts According to EPA in its October 1990 Draft – New Source Review Workshop Manual, for most types of soil and vegetation, ambient concentrations of criteria pollutants below the secondary NAAQS will not result in harmful effects. In addition, EPA provides a screening procedure for the impacts of air pollutant sources on plants, soils, and animals.9 Solvay has conducted a search for information regarding soils and vegetation in the vicinity of the facility. As described further in Section 8.2.3, maximum predicted air quality impacts from Solvay are less than both the secondary NAAQS and EPA’s screening thresholds for soils and vegetation and will not adversely affect these resources.

8.2.1 Soils Survey The physiography of the area in the region of the Solvay facility is characterized by alluvial fans, piedmont plains, and pediments slopes from the surrounding mountains that form broad intermountain basins. The topography ranges from nearly level to steep. Most of the soils formed in alluvium, slope alluvium, or residuum derived from sedimentary materials. Many of the soils are shallow or moderately deep to shale or sandstone bedrock.

9 EPA. A Screening Procedure for the Impacts of Air Pollutant Sources on Plants, Soils, and Animals. December 12, 1980. EPA 450/2-81-078.

83 Baseline information used to characterize soils in the vicinity of the Solvay facility was derived from the University of Wyoming, Soils of Wyoming: A Digital Statewide Map at 1:500,000-Scale, data review and analyses (Munn and Arneson 1998)10. This mapping was developed using soil-landscape models and available data in the form of published soil surveys, maps, and reports of the Natural Resources Conservation Service (NRCS), the USFS, the Bureau of Land Management (BLM), and numerous theses and scientific papers published by the Wyoming Agricultural Experiment Station and the University of Wyoming.

Based on this data source, regional source soil resources in the vicinity of the Solvay facility are characterized as Soil Zone 10 (Green River Basin. Intermountain Basin. Frigid, aridic). The landscape in this extensive southwestern Wyoming basin environment is dominated by the broad exposure of Tertiary shales and sandstones, many of which are noted for their rich fossil record. Soils on the tertiary bedrock are an association of Haplocambids and Torriorthents, with Fluvents along ephemeral channels and Mollisols on favorable sites. The zone contains Psamments on stabilized sand dunes and salinized soils in playas. Sodium-affected soils (Natrargids) occur on alluvial fans on high-sodium parent materials. Uplifted areas of cretaceous and older rock add to the complexity of the area.

Soil mapping data obtained by Solvay in a Geographical Information Systems (GIS) format provides soil information in the vicinity of the Solvay facility per a soil map unit (SMU) classification system. Within a 10 kilometer by 10 kilometer area surrounding the Solvay facility, the dominant SMU are WY44 (83%), WY10 (16%), and WY17 and WY40 (<1%). Descriptions of these SMU have been provided in environmental assessments (EA) for other facilities in Sweetwater County and are provided below.

The majority of soils (83 percent) located within 10 kilometers of the Solvay facility are Haplargids and Torrifluvents (soil map unit WY44). These categories are fine-loamy over sandy or sandy-skeletal, mixed, mesic. These soils occur on alluvium and slopes of Pleistocene and Holocene age over a variety of bedrocks.

Approximately 16 percent of the soils within 10 kilometers of the Solvay facility are Typic Torripsamments (soil map unit WY10). In this intermountain basin environment, Typic Torripsamments occur on stabilized dunes intermingled with active dune lands. Thin topsoil horizons are evident at the dune surface; however, soil development in these soils is poor. These soils have developed in eolian parent materials. These soils include strongly alkaline fine sand to coarse loamy soils about 60 inches deep, and are excessively drained. These soils occur as nearly level to undulating alluvial bottomlands and fans with scattered dune lands. Where these soils are undisturbed, the sand is stabilized by vegetation, and the potential for water erosion is slight and wind erosion is moderate. In disturbed or destabilized dune communities, the hazard for wind erosion is severe.

Less than one percent of the soils within 10 kilometers of the Solvay facility comprise Rock Outcrop and loamy-skeletal, Typic Torriorthents (soil map unit WY17). These poorly developed stony soils occupy

10 From webpage: http://www.wyomingextension.org/agpubs/pubs/b1069.pdf

84 ridge crests intermixed with areas of rock outcrop. These soils range in depth from very shallow to moderately deep. The soils tend to be much coarser than the soils on the adjacent lower slopes, and contain hard clasts of local bedrock. The adjacent lower slopes generally developed from shale residuum, which weathers to fine textured clays, and slope alluvium. These clays result in poor infiltration, high runoff, and high potential for slumping. Sensitive soils are found on steeper slopes (greater than 25 percent) and areas of exposed bedrock, often associated with badlands.

Less than one percent of the soils within 10 kilometers of the Solvay facility are characterized as soil map unit WY40 described in the subsequent text. Ustic Haplocambids are moderately to weakly developed and occur on gentle to steep slopes. Coarse-loamy, Ustic Torriorthents have soil textures that generally range from silt loams to sandy loams. Loamy-skeletal, Typic Torrifluvents have 35 percent or more rock fragments and textures range from sands to sandy clay loams. This portion of the project area also has shallow and moderately deep Haplocambids and poorly developed Torriorthents occurring on slopes along ephemeral channels. Torrifluvents formed in alluvial deposits along larger gully and drainage bottoms and are very deep. Bottomland soils have developed primarily in alluvial deposits. These bottomland soils can be saline or sodic in relation to the parent material they are derived from.

8.2.2 Vegetation Survey According to WAQSR, Chapter 6, Section 4(b)(i)(B)(I), for the PSD additional impact analyses, the owner or operator need not provide an analysis of the impact on vegetation having no significant commercial or recreational value.

The Solvay facility is located in the Wyoming Basin ecoregion.11 The land use surrounding the Solvay facility is predominantly shrubland with very small areas of bare rock/sand clay and grasslands.12 Shrublands are areas characterized by natural or semi-natural woody vegetation with aerial stems, generally less than 6 meters tall, with individuals or clumps not touching to interlocking. In this region, the chief vegetation is made up of sagebrush (Artemisia tridentata) mixed with short grasses (various Agropyron species or fescue grass).

Most of the Wyoming Basin is sagebrush steppe; actually a shrubland mosaic dominated by Wyoming big sagebrush. In places of shallow soil and on windswept ridges, Wyoming big sagebrush may be replaced by black sagebrush or communities of cushion plants. Gardner saltbush and greasewood are especially common on alkaline soils and basin big sagebrush or silver sagebrush may thrive in more moist locations.13 Moist alkaline flats support alkali-tolerant greasewood. With the exception of the few riparian areas, much of the sagebrush steppe is devoid of trees.

11 From LandScope America webpage: http://www.landscope.org/explore/natural_geographies/ecoregions/Wyoming%20Basins/ 12 From National Land Cover Database webpage: http://www.mrlc.gov/index.php 13 From LandScope America webpage: http://www.landscope.org/explore/natural_geographies/ecoregions/Wyoming%20Basins/

85 Solvay has performed a preliminary survey of any potential vegetation with commercial or recreation value in the vicinity of the facility using aerial photographs available from Google Earth. From the Google Earth survey, there is no vegetation in the immediate vicinity of the facility (i.e., and hence maximum modeled impact locations) that would have significant commercial or recreational value.

However, Solvay has identified some isolated areas of cultivated land (assumed hay farming) with potential commercial value located approximately 6 and 8 kilometers to the southeast of the facility adjacent to Blacks Fork of the Green River (a tributary of the Green River).

8.2.3 Modeled Impacts to Soils and Vegetation As provided in Section 6.7.2 the maximum impacts from the ARGO project result in impacts below secondary NAAQS standards that provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. In addition, modeled impacts of several criteria pollutants are compared to concentrations at which adverse growth or tissue injury has been reported in the literature for exposed vegetation.14 Predicted concentrations for the project area were well below the thresholds for damage, as shown in Table 8-1.

Table 8-1. Comparison of Predicted Project Impacts to Vegetation Damage Threshold

Threshold Concentration Solvay Facility Averaging For Sensitive Vegetation Max. Modeled Modeling Averaging

Pollutant Period (g/m3) Impact (g/m3) * Period Used

Carbon Monoxide (CO) 1-week 1,800,000 1,580 8-hour

* Reported impacts for all pollutants represent the maximum result from the full-impact modeling (Solvay facility + competing sources).

14 EPA. “A Screening Procedure for the Impacts of Air Pollutant Sources on Plants, Soils, and Animals.” December 12, 1980. EPA 450/2-81-078.

86 8.3 Visibility Impairment Analysis The Solvay project area does not include any protected Class II views that have been identified by WDEQ. For visibility impairment analysis for all other Class II areas, a comparison to the secondary ambient standards (WAAQS/NAAQS) is made as the secondary standards are intended to protect these resources. As shown in Section 6.7.2 maximum modeled impacts from the project are less than the secondary ambient standards and the project will not adversely impair visibility at Class II areas.

In regard to Class I area visibility protection, as described in Section 7.2, Solvay has concluded that an AQRV analysis is not necessary for the ARGO project based on projected emissions for the project and distances from the Solvay facility to surrounding Class I areas.

87 9.0 OZONE ASSESSMENT

This section describes an evaluation of impacts of ozone for the ARGO project. The regulatory background for this analysis is previously described in Section 6.5.5.1.

Secondary PM2.5 and O3 are closely related to each other in that they share common sources of emissions and are formed in the atmosphere from chemical reactions with similar precursors. Air pollutants formed through chemical reactions in the atmosphere are referred to as secondary pollutants. For example, ground-level O3 is predominantly a secondary pollutant formed through photochemical reactions driven by emissions of NOX and VOCs in the presence of sunlight. O3 formation is a complicated nonlinear process that depends on meteorological conditions in addition to VOC and NOX concentrations. O3 concentrations are typically highest in and downwind of urban areas.

As discussed in Section 6.5.5.1, per EPA’s December 2, 2016 MERPs guidance, EPA source #12 is the nearest hypothetical source to the Solvay facility and is located 86 miles southwest of Solvay. As presented in Solvay’s April 4, 2019 modeling protocol, WDEQ approved the use of data from this hypothetical source to assess secondary PM2.5 impacts from the Solvay facility. Source #12 is located in rural northeastern Utah, away from the influence of urban/metropolitan area precursor emissions, and is representative of Solvay’s rural location. Per EPA’s April 30, 2019 MERPs guidance, EPA also included PGM data from an additional hypothetical source (#34) located in southwest Wyoming approximately 40 miles to the northwest of the Solvay facility. Data from these hypothetical source locations are discussed below.

For Solvay’s ARGO project modification, the maximum production facility-wide potential O3 precursor emissions will consist of a 615 tpy reduction of NOX emissions and a net emissions increase of 2,331 tpy of VOCs.

Ozone impacts are estimated by interpolation between the impacts from EPA’s PGM. Solvay’s net emissions of NOx (decrease) and net emissions of VOC (increase) are compared to emissions of EPA’s PGM for hypothetical source #12 and source #34 to determine the emission scenarios that most closely match Solvay’s emissions. A linear relationship between those scenarios’ emissions and ozone impacts will be determined and assessed at Solvay’s net emission rates to estimate the expected change in ozone formation due to the project. The total estimate of ozone formation is determined by combining the ozone increase from the net increase in VOC emissions with the ozone reduction associated with a decrease in NOx emissions. Note that with the large decrease in NOx emissions from the facility, as a result of the conversion of Solvay sources #17, #18, #19 from coal combustion to NG combustion, the ARGO project is expected to decrease ozone impacts from the facility compared to the current facility configuration.

88 Table 9-1, parts a. and b., demonstrate that Solvay’s expected contribution to ozone formation is less than the 8-hour ozone significant impact level of 1 ppb and no further analysis is necessary. Part a. utilizes EPA hypothetical source #12 data and part b. utilizes EPA hypothetical source #34 data. The PGM output data for sources #12 and #34 are very similar and do not affect overall conclusions of the analyses. The Solvay ARGO project will not cause or contribute to an exceedance of the ambient standards for ozone.

Table 9-1. Solvay Ozone Impacts a. Using EPA PGM Source #12 Data

Solvay 8-hour O3 Significant Parameter EPA PGM Value * ARGO SIL (ppb) Impact?

NOx Emissions (tpy) 500 1,000 -616 ------

O3 from NOx Precursors (ppb) 1.23 2.04 -1.42 ------

VOC Emissions (tpy) 1,000 3,000 2,331 ‐‐‐ ‐‐‐ O3 from VOC Precursors (ppb) 0.18 1.12 0.81 ‐‐‐ ‐‐‐ Total 8-hour O from NOx and VOC Precursors 3 ------0.6 1.0 No (ppb)

* Based on EPA PGM, Source #12.

b. Using EPA PGM Source #34 Data

Solvay 8-hour O3 Significant Parameter EPA PGM Value * ARGO SIL (ppb) Impact?

NOx Emissions (tpy) 500 1,000 -616 ------

O3 from NOx Precursors (ppb) 1.21 2.09 -1.42 ------

VOC Emissions (tpy) 500 3,000 2,331 ‐‐‐ ‐‐‐ O3 from VOC Precursors (ppb) 0.12 1.12 0.85 ‐‐‐ ‐‐‐ Total 8-hour O from NOx and VOC Precursors 3 ------0.6 1.0 No (ppb)

* Based on EPA PGM, Source #34 ; 3,000 tpy VOC data from Source #12.

89 10.0 INHALATION RISK ASSESSMENT

A screening risk assessment addressing the impacts HAP emissions from the project (new product dryer and debottlenecked combustion sources) is provided in this section.

The inhalation risk assessment for hazardous air pollutants was conducted using a Tier 1 (screening level) approach to estimate the chronic carcinogenic risks for the project. The analysis followed the facility- specific assessment guidance developed by the EPA as described in the document Air Toxics Risk Assessment Reference Library, Volume 2, Facility-Specific Assessment, using the AERMOD model. The Tier 1 analysis provides a conservative single estimate of maximum ambient air concentration used to estimate the chronic cancer inhalation risk based on an assumption that the maximum-exposed individual could reside at the offsite location of maximum concentration (and theoretically be exposed to impacts 24 hours per day over a period of a full lifetime), whether or not a person actually lived there.

The Inhalation Unit Risk (IUR) from EPA's HAPs Summary15 was used as the screening levels for chronic carcinogenic risk (dose response values) and is provided on Appendix G, Page 1. The IUR is defined as the upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent via inhalation per 1 μg/m3 over a lifetime. The interpretation of unit risk is as follows: if the IUR = 1.5 × 10-6 per μg/m3, then not more than 1.5 excess tumors may be expected to develop per 1,000,000 people if exposed continuously for a lifetime to 1 μg/m3 of the chemical inhaled. The number of expected tumors may be less; it may even be none.

The estimated excess lifetime cancer risk (R) is found by multiplying the lifetime average concentration (EC) and IUR for each HAP. The cumulative risk is the sum of the individual risk values. If the combined risk is less and one-in-a-million, then the risk is assumed insignificant and the analysis is complete. The excess lifetime cancer risk was calculated using the following equation:

Risk = EC x IUR

where, Risk = excess lifetime cancer risk estimate (unitless), EC = modeled exposure concentration based on a lifetime of continuous inhalation exposure to an individual HAP (g/m3), IUR = dose response value, i.e., the inhalation risk estimate for that HAP [1/(g/m3)].

15 https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants

90 As discussed in the modeling protocol, only emissions from the ARGO project (new sources, existing modified sources, and debottlenecked combustion sources) were considered and emissions from these sources are provided in Appendix G. Emission factors for the carcinogenic HAPs from the new NG-fired product dryer and debottlenecked combustion sources were obtained from AP-42, Section 1.4 for NG combustion.

To focus the analysis on the most significant HAPs, Solvay applied the toxicity-weighted screening analysis (TWSA), as described in the EPA document Air Toxics Risk Assessment Reference Library, Volume 2, Facility-Specific Assessment. Page 3 of Appendix G: provides the entire TWSA and Table 10-1 presents a summary of the TWSA, which uses the product of the expected emissions for a given HAP and the dose response value for that HAP. The products calculated in this way were ranked from highest to lowest, and the HAPs within the 99th cumulative percentile were selected to carry forward to the inhalation risk modeling.

Table 10-1. Toxicity-Weighted Screening for Carcinogenic HAPs

X = Total Y = Dose Response Emissions Risk Factor Percent of Cumulative

Total Pollutant Ref. (tpy) (1/g/m3) X * Y (%) (X * Y) Cadmium CAD 1.24E-02 0.0018 2.23E-05 39.4% 39.4% 7,12-Dimethylbenz(a)anthracene DIM 1.81E-04 0.071 1.28E-05 22.6% 61.9% Formaldehyde FRM 8.46E-01 0.000013 1.10E-05 19.4% 81.3% Arsenic ARS 2.26E-03 0.0043 9.71E-06 17.1% 98.4%

For the model runs that were used to determine the long-term average impacts from the four modeled carcinogenic HAPs, Solvay modeled three years of annual impacts. For each of these HAPs, Solvay determined the average of these three years of concentrations to determine a long-term average on a receptor-by-receptor basis. Then the risk contributions (Risk = EC x IUR) from each HAP were summed to determine a total risk value on a receptor-by-receptor basis. AERMOD only generates modeled output to five decimal places, and not in scientific notation, so the emission rates used in the modeling analysis were the actual rates calculated in Appendix G multiplied by 1000. Then, the resulting impacts were divided by 1000 so that very small impacts could be accounted for numerically.

The overall highest predicted increased cancer risk was very low at 0.13 per million at a receptor near the eastern ambient boundary of the facility (UTM Easting = 606,000.0 meters, UTM Northing = 4,594,500.0 meters). Table 10-2 presents a summary of the results of the risk analysis.

91 Table 10-2. Carcinogenic Inhalation Risk Summary at Maximum Impact Receptor

Modeled Dose Response Calculated Result, EC 1 Risk Factor, IUR Risk

Pollutant Ref. (g/m3) (1/g/m3) ** EC * IUR Arsenic ARS 5.27E-06 0.0043 2.3E-08 Cadmium CAD 2.90E-05 0.0018 5.2E-08 7,12-Dimethylbenz(a)anthracene DIM 4.23E-07 0.071 3.0E-08 Formaldehyde FRM 1.98E-03 0.000013 2.6E-08 Total Increased Cancer Risk (per million) > 0.13

1 At maximum modeled receptor.

92 Appendix A: ARGO Project Process Flow Diagram

Bin 17 280,600 acfm 46 160 200 TPH "A" Calciner 170,600 scfm 1 Shaft 2 Shaft Coal EP-1 11,500 Natural Gas acfm 200 MMBtu/hr CA-1 18 BF-62 Ore Transfer Station #2 Bin Baghouse 160 200 TPH Coal "B" Calciner EP-2 CEM (NOX only) COM Raw Trona Ore 104 103 Natural Gas 79 6.78 MMTPY 200 MMBtu/hr CA-2 EP-3 4,100 4,300 12,250 Bin acfm acfm Bin BF-8 acfm BF-87 West Ore Reclaim East Ore Reclaim 200 TPH WS-007

BF-132 "C" Calciner Ore Transfer Baghouse Baghouse EP-5 48 Baghouse Splitter Natural Gas Coal Hopper 250 MMBtu/hr CA-3 Steam for Natural Gas Boiler 350387 MMBtu/hr Primary 99 Bin Process Heat Crusher Primary 47,000 325 TPH CR-10 Screens acfm "D" Calciner SN-17,1,2 EP-7 80 BF-75 Crusher Natural Gas 76 Bins 400 MMBtu/hr CA-4 Baghouse #2 19 36,000 acfm BF-131 Primary Ore Primary 2A CEM (NOX only) COM Screening Crushers 35,000 Coal processes to be removed: Baghouse CR-8,1,2 acfm 10 Coal Crushing & Storage (Baghouse) EP-4

Primary BF-1 Ore Crusher Building #1 11 Coal Transfer Station (Baghouse) Leach Tanks Settling Tanks Screens Baghouse 14 Boiler Coal Bunker (Baghouse) WS-8 SN-31,32 24 Boiler Ash Silo (Baghouse) Primary Filters Secondary Filters 67 Bottom Ash (Baghouse) Coal Evaporators 100 Calciner Coal Bunker (Baghouse) Natural Gas Crystallizers Steam for Boiler 350387 MMBtu/hr Centrifuges Process Heat 3 New Centrifuges New MVR Crystallizer 16 50 (30,000 lb/hr Steam Load) 34,100 26,000 51 acfm acfm 110 BF-24 Dryer Area BF-84 Dryer Area EP-6 143,100 acfm 15 85 TPH Baghouse 155 TPH Baghouse 20,000 acfm 111 42,800 dscfm 15,890 scfm Screens Screens BF-139 Dryer Area EP-9 200 TPH Baghouse 109 Dryer Dryer Screens

W S-4 DR-1 Natural Gas DR-5 CEM (NO only) 81 New Dryer X Mill 150 MMBtu Mill 10,000 Steam acfm Natural Gas DR-8 Natural Gas Steam for Boiler BF-137 Dryer Area 200 MMBtu/hr Mill Process Heat 254 MMBtu/hr 129,100 acfm 85 TPH Baghouse 161 200 TPH 82 40,400 dscfm Screens Screens EP-8 W S-5 Dryer Dryer

DR-2 Natural Gas DR-6 7 Mill 200 MMBtu/hr Mill 18,400 Steam acfm

Reject BF-32 Product Loadout Station Baghouse 6A 52 14,850 5,300 acfm acfm New Equipment and Modifications BF-31 Product Silos Top #1 BF-79 Product Silos 6B 53 are Labeled in Red Text Baghouse Top #2 14,000 11,200 Baghouse To Atmosphere Baghouse acfm acfm BF-86 BF-33 Product Silos Product Silos Bottom #1 Bottom #2 Air Flow Baghouse Baghouse Venturi Wet Silo Silo Silo Silo Silo Silo Material Transfer Scrubber 1 2 3 4 5 6 Soda Ash Product Loadout to Truck/Rail 3.60 4.1 MMTPY ESP Baghouse Control Area Product Silos

SO2 Scrubber Enclosed Appendix A, Page 1 Appendix B: Emissions for New and Modified Sources

PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 2 New-Mod AIR EMISSION CALCULATIONS SUBJECT: DATE: New/Modified Potential Emissions March 19, 2019

#18 - #1 Natural Gas-Fired Boiler #19 - #2 Natural Gas-Fired Boiler Operating Schedule 8,760 hr/yr, ea 2 units Exhaust Parameters 76,425 scfm, ea Detroit Stoker Co, 1/9/2019 letter 174,179 acfm, ea. 10% moisture 152,900 scfm, tot 400 F Detroit Stoker Co, 1/9/2019 letter Design Throughput 387 MMBtu/hr, N.G., ea, HHV Permit No. 3-1-126

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 7.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 5.8 25.3 0.0075 lb/MMBtu NOX 0.024 lb/MMBtu Detroit Stoker Co, 1/9/2019 letter 18.6 81.4 CO 0.074 lb/MMBtu Detroit Stoker Co, 1/9/2019 letter 57.3 250.9 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 4.2 18.3 0.0054 lb/MMBtu

SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.5 2.0

CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 90,540 396,567 CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 1.71 7.47

N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.17 0.75 CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 90,634 396,976 117 lb/MMBtu

#17 - "A" and "B" Calciners Operating Schedule 8,760 hr/yr, ea 2 units Exhaust Parameters 85,603 scfm, ea Detroit Stoker Co, 8/13/2018 lette 70 F, std 140,300 acfm, ea. 85,280 scfm, each 68 F, std 230 F Detroit Stoker Co, 8/13/2018 letter 280,600 acfm, total Design Throughput 200 ton/hr, ea Proposed limit 170,600 scfm, total 200 MMBtu/hr, N.G., ea, HHV Detroit Stoker Co, 8/13/2018 letter

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.015 gr/scf Required vendor guarantee 22.0 96.4

NOX 0.036 lb/MMBtu Detroit Stoker Co, 8/13/2018 lette 14.4 63.1 CO 3.81 lb/ton T. Brown, Solvay, 8/3/2018 1,524 6,675.1 3.81 lb/MMBtu VOC 1.7 lb/ton Proposed rate 680 2,978.4

SO2 0 lb/MMscf Negligible - soda ash adsorption 0.0 0.0 CO2e 400 lb/ton AP-42 Table 8.12-4 (1/95) Monoh 1.6E+05 7.0E+05

Site Pressure Calculation http://www.sensorsone.com/altitude-pressure-units-conversion/ ft mmHg 0 29.921 6,000 23.978 7,000 23.088 6,239 23.765 0.794 atm

Conversions GWP 40 CFR 98, Table A-1 Subpart A 60 s/min and min/hr 0 C, std 273.15 C to K Metric CO2 1 7,000 gr/lb 68 F, std 459.67 F to R English CH4 25 2,000 lb/ton 2.20462 lb/kg N2O 298 1,020 Btu/scf AP-42 Table 1.4-2 (7/98), footnote a 3 3 35.315 ft /m

Appendix B, Page 1 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 2 New-Mod AIR EMISSION CALCULATIONS SUBJECT: DATE: New/Modified Potential Emissions March 19, 2019

#81 - "D" Train Dryer Area Non-NSR Modification Operating Schedule 8,760 hr/yr, ea Exhaust Parameters 10,000 acfm Permit No. 3-1-126 7,950 scfm

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.0073 gr/dscf Permit No. 3-1-126 0.5 2.2

#82 - DR-6 Product Dryer Non-NSR Modification Operating Schedule 8,760 hr/yr Exhaust Parameters 40,400 dscfm 129,100 acfm Dwg. 550-PF-142B v5, stream 521 Design Throughput 200 ton/hr Proposed limit 43.51% water by vol. Dwg. 550-PF-142B v5, stream 521 200 MMBtu/hr, N.G. 297.7 F Dwg. 550-PF-142B v5, stream 521

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.01 gr/dscf Permit No. 3-1-126 3.45 15.1

NOX 0.15 lb/MMBtu Permit No. 3-1-126 30 131.4 CO 1.5 lb/MMBtu Permit No. 3-1-126 300 1,314.0 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 1.1 4.7 0.0054 lb/MMBtu SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.1 0.5

CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 23,395 102,472 CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.44 1.93 N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.04 0.19 CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 23,420 102,578 117 lb/MMBtu

#110 - "E" Train Dryer Area Operating Schedule 8,760 hr/yr, ea Exhaust Parameters 20,000 acfm Proposed flow 15,890 scfm

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.006 gr/dscf Required vendor guarantee 0.8 3.6

#111 - DR-8 Product Dryer Operating Schedule 8,760 hr/yr 3 Exhaust Parameters 143,100 acfm 243,010 m /h FLSmidth, Dwg. 50090360 v.2.0, Stream G8 350.6 F 177 C FLSmidth, Dwg. 50090360 v.2.0, Stream G8 42.11% 42.11% water by vol. FLSmidth, Dwg. 50090360 v.2.0, Stream G8 3 42,800 dscfm 117,210 Nm /h (wet) FLSmidth, Dwg. 50090360 v.2.0, Stream G8 Design Throughput 200 ton/hr Proposed limit 200 MMBtu/hr, N.G., HHV FLSmidth, Dwg. 50090360 v.2.0, Stream S90, converted to HHV

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.01 gr/dscf Required vendor guarantee 3.67 16.1 NOX 0.15 lb/MMBtu FLSmidth, Dwg. 50090360 v.2.0 30.0 131.4 CO 1.46 lb/MMBtu FLSmidth 11/5/2018 email 292.0 1,279 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 1.1 4.7 0.0054 lb/MMBtu

SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.1 0.5 CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 23,395 102,472 CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.44 1.93

N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.04 0.19

CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 23,420 102,578 117 lb/MMBtu

Appendix B, Page 2 Appendix C: Project Emissions Inventory Summaries

PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Net Change in Emissions

Past Actuals to Projected Actuals (or Potentials) Emissions (ton/yr) Description PM* NOX CO VOC SO2 CO2e Baseline Actual Emissions of Debottlenecked Sources (2016-2017) 203 1,275 4,940 1,212 48 1,314,384

Projected Actual Emissions of Debottlenecked Sources ** 147 252 5,884 537 1 1,060,384 Potential Emissions of New and Modified Sources 159 407 9,519 3,006 3 1,302,932 Contemporaneous Increases and Decreases 0.9 N/A N/A N/A N/A N/A Post-Modification Subtotal 306 660 15,403 3,543 4 2,363,316

Net Change in Emissions 103 -615 10,463 2,331 -44 1,048,932

PSD Significant Thresholds 10 40 100 40 40 75,000

PSD Triggered Yes No Yes Yes No Yes

* Assumes PM=PM10=PM2.5

** The projected actual emissions for the debottlenecked sources of NOx and SO2 are represented by potential emissions.

Potential Emissions of Lead Emissions (ton/yr) Description Lead Debottlenecked Sources 0.0023 Modified Sources 0.0030 New Sources 0.0004 Post-Modification Subtotal 0.0056

PSD Significant Thresholds 0.6

PSD Triggered No

Appendix C, Page 1 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Reported Actual Emissions 2-Year Average Emissions (ton/yr)

Year PM NOX CO VOC SO2 PM NOX CO VOC SO2 2013 209.9 1,418.7 4,819.9 1,047.1 41.9 201 2014 215.6 1,376.5 4,981.3 1,065.9 28.4 212.8 1,397.6 4,900.6 1,056.5 35.1 201 2015 190.6 1,327.1 5,039.3 1,087.6 24.5 203.1 1,351.8 5,010.3 1,076.8 26.4 201 2016 188.1 1,298.3 4,887.5 1,115.3 63.6 189.3 1,312.7 4,963.4 1,101.5 44.0 201 2017 218.1 1,251.8 4,992.7 1,308.9 32.0 203.1 1,275.0 4,940.1 1,212.1 47.8 List of sources affected by the proposed modifications: Selected Baseline Actual Emissions (2016-2017) Src ID Description 2016-2017 203.1 1275.0 4940.1 1212.1 47.8 02A Ore Crusher Building #1 06A Product Silos - Top #1 06B Product Silos - Bottom #1 07 Product Loadout Station 10 Coal Crushing & Storage 11 Coal Transfer Station 14 Boiler Coal Bunker 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 16 Dryer Area 17 "A" and "B" Calciners 18 #1 Coal Fired Boiler 19 #2 Coal Fired Boiler 24 Boiler Fly Ash Silo 46 Ore Transfer Station 48 "C" Calciner 50 "C" Train Dryer Area 51 Product Dryer #5 52 Product Silo - Top #2 53 Product Silo - Bottom #2 67 Bottom Ash 76 "D" Train Primary Ore Screening 79 Ore Transfer Point 80 "D" Ore Calciner 81 "D" Train Dryer Area 82 DR-6 Product Dryer 99 Crusher Baghouse #2 100 Calciner Coal Bunker 103 East Ore Reclaim 104 West Ore Reclaim 109 Gas-fired Package Boiler

Reported Actual Production 2-Year Soda Ash Baseline Period Year MMTPY MMTPY 2013 2.55 2013-2014 2014 2.53 2.54 2014-2015 2015 2.61 2.57 2015-2016 2016 2.42 2.51 2016-2017 2017 2.61 2.52

Appendix C, Page 2 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Baseline Actual Emissions of Debottlenecked Sources Actual Activity Baseline Actual Emissions (ton/yr)

Src ID Description hr/yr thru/yr units PM NOX CO VOC SO2 02A Ore Crusher Building #1 8,760 1,578,397 ton 7.01 0 0 0 0 06A Product Silos - Top #1 8,760 119,728 ton 1.31 0 0 0 0 06B Product Silos - Bottom #1 202 117,709 ton 0.05 0 0 0 0 07 Product Loadout Station 4,380 2,516,486 ton 2.63 0 0 0 0 10 Coal Crushing & Storage 3,333 264,627 ton 0.50 0 0 0 0 11 Coal Transfer Station 3,611 264,627 ton 0.36 0 0 0 0 14 Boiler Coal Bunker 2,446 181,646 ton 0.49 0 0 0 0 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 8,403 1,024,711 ton 2.65 0 000 16 Dryer Area 8,370 747,501 ton 3.77 0 0 0 0 17 "A" and "B" Calciners 7,073 1,174,636 ton 49.41 198.26 974.96 869.23 2.94 18 #1 Coal Fired Boiler 8,405 1,802,667 MMBtu 11.72 448.91 50.22 1.80 29.53 19 #2 Coal Fired Boiler 8,384 1,798,768 MMBtu 10.10 451.60 69.42 1.80 14.61 24 Boiler Fly Ash Silo 8,760 9,673 ton 1.31 0 0 0 0 46 Ore Transfer Station 8,760 1,578,397 ton 3.11 0 0 0 0 48 "C" Calciner 8,328 1,081,636 ton 27.94 23.67 1,085.91 178.47 0 50 "C" Train Dryer Area 8,518 710,914 ton 2.98 0 0 0 0 51 Product Dryer #5 8,518 710,914 ton 0.68 32.49 150.59 2.21 0 52 Product Silo - Top #2 8,580 2,559,072 ton 2.14 0 0 0 0 53 Product Silo - Bottom #2 4,179 2,516,486 ton 0.94 0 0 0 0 67 Bottom Ash 8,760 9,673 ton 2.06 0 0 0 0 76 "D" Train Primary Ore Screening 8,570 1,291,029 ton 10.50 0 0 0 0 79 Ore Transfer Point 8,570 1,291,029 ton 3.60 0 0 0 0 80 "D" Ore Calciner 8,444 1,803,339 ton 30.58 42.95 2,431.83 153.28 0 81 "D" Train Dryer Area 8,415 943,176 ton 2.10 0 0 0 0 82 DR-6 Product Dryer 8,415 943,176 ton 4.88 67.12 143.53 2.50 0 99 Crusher Baghouse #2 8,760 1,578,397 ton 14.02 0 0 0 0 100 Calciner Coal Bunker 2,427 82,981 ton 0.24 0 0 0 0 103 East Ore Reclaim 8,760 789,198 ton 1.45 0 0 0 0 104 West Ore Reclaim 8,760 789,198 ton 1.18 0 0 0 0 109 Gas-fired Package Boiler 7,155 873,480 MMBtu 3.36 10.02 33.63 2.79 0.72 Total 203 1,275 4,940 1,212 48 thru/yr = ton/yr or MMBtu/yr chk chk chk chk chk

Baseline Actual GHG Emissions of Existing Sources and Projected Actual GHG Emissions of Debottlenecked Sources 63% Increase Baseline Baseline Projected Actual Emissions

Actual Activity Emission Factors CO2e Actual Activity CO2e

Src ID Description Material thru/yr units CO2 CH4 N2O units ton/yr thru/yr units ton/yr Debottlenecked Sources 48 "C" Calciner Throughput 1,081,636 ton 400 lb/ton 2.16E+05 1,752,000 ton 3.50E+05 51 Product Dryer #5 Fuel 602,343 MMBtu 53.06 0.001 0.0001 kg/MMBtu 3.53E+04 980,002 MMBtu 5.74E+04 80 "D" Ore Calciner Throughput 1,803,339 ton 400 lb/ton 3.61E+05 2,847,000 ton 5.69E+05 109 Gas-fired Package Boiler Fuel 873,480 MMBtu 53.06 0.001 0.0001 kg/MMBtu 5.11E+04 1,421,138 MMBtu 8.32E+04 Modified Sources 17 "A" and "B" Calciners Throughput 1,174,636 ton 400 lb/ton 2.35E+05 See Potential Emission 18 #1 Coal Fired Boiler Fuel 1,802,667 MMBtu 93.28 0.011 0.0016 kg/MMBtu 1.87E+05 calculations on Page 4 19 #2 Coal Fired Boiler Fuel 1,798,768 MMBtu 93.28 0.011 0.0016 kg/MMBtu 1.86E+05 82 DR-6 Product Dryer Fuel 731,037 MMBtu 53.06 kg/MMBtu 4.28E+04 Total 1.31E+06 1.06E+06

Conversion GWP 40 CFR 98, Table A-1 Subpart A 2.20462 lb/kg CO2 1 2,000 lb/ton CH4 25 N2O 298

Appendix C, Page 3 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 4 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Projected Actual Emissions of Debottlenecked Sources Proposed Product Increase: 2.52 4.1 62.7% Basis for Permit Projected Actual Emissions (ton/yr)*

Src ID Description Projected Actuals units Limit PM NOX CO VOC SO2 02A Ore Crusher Building #1 8,760 hr/yr 8,760 7.01 0 0 0 0 06A Product Silos - Top #1 8,760 hr/yr 8,760 1.31 0 0 0 0 06B Product Silos - Bottom #1 329 hr/yr 8,760 0.08 0 0 0 0 07 Product Loadout Station 7,126 hr/yr 8,760 4.28 0 0 0 0 10 Coal Crushing & Storage 0 hr/yr 8,760 00000 11 Coal Transfer Station 0 hr/yr 8,760 00000 14 Boiler Coal Bunker 0 hr/yr 8,760 00000 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 1,489,200 thru/yr ton 1,489,200 3.85 0 0 0 0 16 Dryer Area 8,760 hr/yr 8,760 3.94 0 0 0 0 17 "A" and "B" Calciners 0 hr/yr 8,760 00000 18 #1 Coal Fired Boiler 0 hr/yr 8,760 00000 19 #2 Coal Fired Boiler 0 hr/yr 8,760 00000 24 Boiler Fly Ash Silo 0 hr/yr 8,760 00000 46 Ore Transfer Station 8,760 hr/yr 8,760 3.11 0 0 0 0 48 "C" Calciner 1,752,000 thru/yr ton 1,752,000 35.04 38.34 1,758.93 289.08 0 50 "C" Train Dryer Area 8,760 hr/yr 8,760 3.07 0 0 0 0 51 Product Dryer #5 1,156,646 thru/yr ton 1,357,800 1.11 52.87 245.00 1.23 0 52 Product Silo - Top #2 8,760 hr/yr 8,760 2.19 0 0 0 0 53 Product Silo - Bottom #2 6,798 hr/yr 8,760 1.53 0 0 0 0 67 Bottom Ash 0 hr/yr 8,760 00000 76 "D" Train Primary Ore Screening 8,760 hr/yr 8,760 10.73 0 0 0 0 79 Ore Transfer Point 8,760 hr/yr 8,760 3.68 0 0 0 0 80 "D" Ore Calciner 2,847,000 thru/yr ton 2,847,000 43.80 67.81 3,839.22 242.00 0 81 "D" Train Dryer Area 0 hr/yr 8,760 00000 82 DR-6 Product Dryer 0 hr/yr 8,760 00000 99 Crusher Baghouse #2 8,760 hr/yr 8,760 14.02 0 0 0 0 100 Calciner Coal Bunker 0 hr/yr 8,760 00000 103 East Ore Reclaim 8,760 hr/yr 8,760 1.45 0 0 0 0 104 West Ore Reclaim 8,760 hr/yr 8,760 1.18 0 0 0 0 109 Gas-fired Package Boiler 1,421,138 thru/yr MMBtu 2,225,040 5.47 12.26 41.17 4.54 0.65 Total 147 171 5,884 537 1 *Emissions are scaled up from the baseline actuals by the Proposed Product Increase: 63%, but not to exceed the current permit limits (PTE).

Potential Emissions of New and Modified Sources Potential Emissions (ton/yr)

Src ID Description PM NOX CO VOC SO2 CO2e Decommissioned Sources 10 Coal Crushing & Storage 0 0 0 0 0 0 11 Coal Transfer Station 0 0 0 0 0 0 14 Boiler Coal Bunker 0 0 0 0 0 0 24 Boiler Fly Ash Silo 0 0 0 0 0 0 67 Bottom Ash 0 00000 100 Calciner Coal Bunker 0 0 0 0 0 0 Modified Sources 17 "A" and "B" Calciners 96.41 63.07 6,675.12 2,978.40 0.00 700,800 18 #1 Natural Gas-Fired Boiler 12.63 40.68 125.43 9.14 1.00 198,488 19 #2 Natural Gas-Fired Boiler 12.63 40.68 125.43 9.14 1.00 198,488 81 "D" Train Dryer Area Non-NSR Modification 2.19 82 DR-6 Product Dryer Non-NSR Modification 15.11 131.40 1,314.00 4.72 0.52 102,578 New Sources 110 "E" Train Dryer Area 3.58 111 DR-8 Product Dryer 16.07 131.40 1,278.96 4.72 0.52 102,578 Total 159 407 9,519 3,006 3 1,302,932

Appendix C, Page 4 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 5 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Potential Emissions of all Existing Sources Operation 8,760 hr/yr New or Potential Annual Emissions (lb/hr) Potential Annual Emissions (ton/yr)

Src ID Description Modified PM NOX CO VOC SO2 PM NOX CO VOC SO2 02A Ore Crusher Building #1 no 1.60 7.01 0 0 0 0 06A Product Silos - Top #1 no 0.30 1.31 0 0 0 0 06B Product Silos - Bottom #1 no 0.51 2.23 0 0 0 0 07 Product Loadout Station no 1.20 5.26 0 0 0 0 10 Coal Crushing & Storage YES 0.3 1.31 0 0 0 0 11 Coal Transfer Station YES 0.2 0.88 0 0 0 0 14 Boiler Coal Bunker YES 0.4 1.75 0 0 0 0 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) no 3.00 1.80 00013.14 7.88 0 0 0 16 Dryer Area no 0.90 3.94 0 0 0 0 17 "A" and "B" Calciners YES 30.0 131.40 0 0 0 0 18 #1 Coal Fired Boiler YES 5.00 245.00 17.50 7E-07 70.00 21.90 1,073.10 76.65 0.00 306.60 19 #2 Coal Fired Boiler YES 5.00 245.00 17.50 7E-07 70.00 21.90 1,073.10 76.65 0.00 306.60 24 Boiler Fly Ash Silo YES 0.30 1.31 0 0 0 0 46 Ore Transfer Station no 0.71 3.11 0 0 0 0 48 "C" Calciner no 8.00 15.00 762 340 0 35.04 65.70 3,337.56 1,489.20 0 50 "C" Train Dryer Area no 0.70 3.07 0 0 0 0 51 Product Dryer #5 no 2.40 18.00 225 0.28 0.09 10.51 78.84 985.50 1.23 0.39 52 Product Silo - Top #2 no 0.50 2.19 0 0 0 0 53 Product Silo - Bottom #2 no 0.45 1.97 0 0 0 0 67 Bottom Ash YES 0.47 2.06 0 0 0 0 76 "D" Train Primary Ore Screening no 2.45 10.73 0 0 0 0 79 Ore Transfer Point no 0.84 3.68 0 0 0 0 80 "D" Ore Calciner no 10.00 20.00 1,048 553 0 43.80 87.60 4,590.24 2,419.95 0 81 "D" Train Dryer Area YES 0.50 2.19 0 0 0 0 82 DR-6 Product Dryer YES 3.45 30.00 300 0.27 0.12 15.11 131.40 1,314.00 1.18 0.52 99 Crusher Baghouse #2 no 3.2 14.02 0 0 0 0 100 Calciner Coal Bunker YES 0.2 0.88 0 0 0 0 103 East Ore Reclaim no 0.33 1.45 0 0 0 0 104 West Ore Reclaim no 0.27 1.18 0 0 0 0 109 Gas-fired Package Boiler no 1.89 2.80 9.40 1.37 0.15 8.29 12.26 41.17 6.00 0.65 Excluding New/Modified Subtotal 39 58 2,044 894 0 172 252 8,954 3,916 1

Potential GHG Emissions of all Existing Sources Operation 8,760 hr/yr Potential Potential

Actual Activity Emission Factors CO2e Src ID Description Material thru/hr units CO2 CH4 N2O units ton/yr Debottlenecked Sources 48 "C" Calciner Trona 200 ton 400 lb/ton 3.50E+05 51 Product Dryer #5 N.G. 150 MMBtu 53.06 0.001 0.0001 kg/MMBtu 7.69E+04 80 "D" Ore Calciner Trona 325 ton 400 lb/ton 5.69E+05 109 Gas-fired Package Boiler N.G. 254 MMBtu 53.06 0.001 0.0001 kg/MMBtu 1.30E+05 Total 1.13E+06

Conversion GWP 40 CFR 98, Table A-1 Subpart A 2.20462 lb/kg CO2 1 2000 lb/ton CH4 25 N2O 298

Appendix C, Page 5 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 6 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Potential Emissions of Lead Operation 8,760 hr/yr Hourly Annual Lead Src ID Description Fuel MMBtu/hr MMBtu/yr ton/yr Debottlenecked Sources 48 "C" Calciner N.G 250 2,190,000 0.0005 51 Product Dryer #5 N.G 150 1,314,000 0.0003 80 "D" Ore Calciner N.G 400 3,504,000 0.0009 109 Gas-fired Package Boiler N.G 254 2,225,040 0.0005 Modified Sources 17 "A" and "B" Calciners N.G 400 3,504,000 0.0009 18 #1 Natural Gas-Fired Boiler N.G 387 3,390,120 0.0008 19 #2 Natural Gas-Fired Boiler N.G 387 3,390,120 0.0008 82 DR-6 Product Dryer N.G 200 1,752,000 0.0004 New Sources 111 DR-8 Product Dryer N.G 200 1,752,000 0.0004 Total 0.0056

Lead Emission Factor 0.0005 lb/MMscf AP-42, Section 1.4, Table 1.4-2 (Rev. 7/98)

Conversion 2,000 lb/ton 1,020 Btu/scf AP-42 Table 1.4-2 (7/98), footnote a

Appendix C, Page 6 Appendix D: Contemporaneous Source Emissions

PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 4 Contemp. ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 2, 2019

LIST OF PERMIT ACTIONS DURING CONTEMPORANEOUS PERIOD WDEQ New or 1 WDEQ Reference Date Source ID(s) Source Description Existing Source? MD-7431A3 3/21/2015 15 DR-1 & 2 Steam Tube Dryers Existing 105 S-300 Dryer #1 Existing 106 S-300 Silo and Rail Loadout #1 Existing 48 "C" Calciner Existing 80 "D" Calciner Existing Waiver P0020929 6/21/2016 6A Product Silo - Top #1 Existing 6B Product Silo - Bottom #1 Existing 7 Product Loadout Station Existing 52 Product Silo - Top #2 Existing 53 Product Silo - Bottom #2 Existing 81 "D" Train Dryer Area Existing 82 DR-6 Product Dryer Existing 33 Sulfur Burner Existing 35 Sulfite Dryer Existing 36 Sulfite Product Bin #1 Existing 37 Sulfite Product Bin #2 Existing 38 Sulfite Product Bin #3 Existing 64 Sulfite Blending #2 Existing 65 Sulfite Blending #1 Existing 70 Sodium Sulfite Bagging Silo Existing 90 Blending Bag Dump #1 Existing 91 Blending Bag Dump #2 Existing 94 Sulfite Loadout Existing Waiver P0022759 3/7/2017 LUD021 (baghouse) Sodium Sulfite Storage Silo BN-505 and Baghouse New Waiver P0022664 3/15/2017 VNT004 Longwall Water Evaporator Vent New Permit No. P0023144 6/12/2017 CH010 MikroPul 25S-10-20 Baghouse New 72 MBS Soda Ash Feed Silo Baghouse 2 Existing Waiver P0023391 8/15/2017 N/A Temporary Trona Ore Stockpile New Permit No. P0023126 9/1/2017 109 254 MMBtu/hr Natural Gas Boiler Existing Waiver P0023391 5/1/2018 82 DR-6 Product Dryer Existing Waiver P0025195 1/24/2019 N/A Operate 2 existing out of service crystallizers Existing

1 Relative to the contemporaneous period from the BO-4 PSD permit issuance in November 2013 until the operation of the ARGO Production Increase commences (i.e., 2020+). 2 For Permit No. P0023144, CH010 is a new source. Source #72 is an existing baghouse with only a service change from soad ash to trona, but with no change in emissions. As a result, CH010 is a considered a creditable emissions increase, but #72 is an existing source with non-creditable emissions (i.e., no emission changes).

Appendix D, Page 1 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 4 Contemp. ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 2, 2019

NON-CREDITABLE PERMIT ACTIONS/EMISSIONS DURING CONTEMPORANEOUS PERIOD WDEQ Source(s) New or Source(s) Currently WDEQ Reference Date(s) Source ID Source Description Existing? 1 Permitted? Reason Not Creditable MD-7431A3 3/21/2015 15 DR-1 & 2 Steam Tube Dryers Existing Yes No emissions changes. 2 105 S-300 Dryer #1 106 S-300 Silo and Rail Loadout #1 48 "C" Calciner 80 "D" Calciner Waiver P0022759 3/7/2017 LUD021 Sodium Sulfite Storage Silo BN-505 / BH New No Waiver never utilized; project was never built Waiver P0023391 8/15/2017 N/A Temporary Trona Ore Stockpile New No: waiver expired 12/29/2017 Source was temporary and is no longer permitted. Permit No. P0023126 9/1/2017 109 254 MMBtu/hr Natural Gas Boiler Existing Yes No emissions changes. 3 Waiver P0023391 5/1/2018 82 DR-6 Product Dryer Existing No: waiver expired Action was temporary and is no longer permitted. Waiver P0025195 1/24/2019 N/A Operate 2 existing out of service crystallizers Existing --- No emissions changes. 4

1 Relative to the contemporaneous period. 2 In MD-7431A3, Solvay requested to modify MD-7431A2 by allowing centrifuges to be vented through the DR1&1 (#15) scrubbers. MD-7431A3 did not change any existing allowable emission limits. 3 In Permit No. P0023126, Solvay requested to modify the NOx lb/MMBtu emission rate for the 254 MMBtu/hr Natural Gas Boiler. Permit No. P0023126 did not change any existing allowable NOx emission limits (lb/hr or ton/year). 4 In Waiver P0025195, per WAQSR Chapter 6, Section 2(k)(viii), the action was insignificant in both emission rate and ambient air quality impact; P0025195 did not change any existing allowable emission limits.

Appendix D, Page 2 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 4 Contemp. ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 2, 2019

CREDITABLE EMISSION INCREASES AT EXISTING SOURCES DURING CONTEMPORANEOUS PERIOD (Division letter, Re Permit Waiver P0020929 Green River Soda Ash Plant, 6/21/2016) Note: The changes for this permit waiver affect the same sources as the debottlenecked ARGO project sources which have larger overall increases in emissions given the large ARGO production expansion. To avoid double counting of emissions from these sources, the higher debottlenecked ARGO project emissions are utilized for these sources for the PSD applicability analysis.

PM10 Increases * WDEQ Source Baseline Projected Net Increase Source ID Description (tpy) (tpy) (tpy) 6A Product Silo - Top #1 1.3 1.3 0 6B Product Silo - Bottom #1 0.1 2.4 2.3 7 Product Loadout Station 2.4 5.3 2.8 52 Product Silo - Top #2 2.1 2.2 0.05 53 Product Silo - Bottom #2 0.9 2.0 1.1 81 "D" Train Dryer Area 2.1 2.2 0.1 82 DR-6 Product Dryer 11.7 14.2 2.5 Subtotal > 20.7 29.6 8.9

* Note that for this permit waiver the emissions netting analysis indicated slight decreases in emissions (or no changes in emissions) from several sources (#33, #35, #36, #37, #38, #64, #65, #70, #90, #91, #94). To be conservative for this analysis, only emissions increases from the Permit Waiver P0020929 are considered for the contemporaneous emissions summary.

NOx Increases * WDEQ Source Baseline Projected Net Increase Source ID Description (tpy) (tpy) (tpy) 6A Product Silo - Top #1 ------6B Product Silo - Bottom #1 ------7 Product Loadout Station ------52 Product Silo - Top #2 ------53 Product Silo - Bottom #2 ------81 "D" Train Dryer Area ------82 DR-6 Product Dryer 66.3 76.9 10.6 Subtotal > 66.3 76.9 10.6

* Note that for this permit waiver the emissions netting analysis indicated slight decreases in emissions (or no changes in emissions) from several sources (#33, #35, #36, #37, #38, #64, #65, #70, #90, #91, #94). To be conservative for this analysis, only emissions increases from the Permit Waiver P0020929 are considered for the contemporaneous emissions summary.

CO Increases WDEQ Source Baseline Projected Net Increase Source ID Description (tpy) (tpy) (tpy) 6A Product Silo - Top #1 ------6B Product Silo - Bottom #1 ------7 Product Loadout Station ------52 Product Silo - Top #2 ------53 Product Silo - Bottom #2 ------81 "D" Train Dryer Area ------82 DR-6 Product Dryer 188.8 197.7 8.9 Subtotal > 188.8 197.7 8.9

VOC Increases WDEQ Source Baseline Projected Net Increase Source ID Description (tpy) (tpy) (tpy) 6A Product Silo - Top #1 ------6B Product Silo - Bottom #1 ------7 Product Loadout Station ------52 Product Silo - Top #2 ------53 Product Silo - Bottom #2 ------81 "D" Train Dryer Area ------82 DR-6 Product Dryer 3.1 3.7 0.6 Subtotal > 3.1 3.7 0.6

Appendix D, Page 3 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 4 4 Contemp. ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 2, 2019

CREDITABLE EMISSION INCREASES AT NEW SOURCES DURING CONTEMPORANEOUS PERIOD

List of New Sources and Related Permitting Information WDEQ Source Source ID Description WDEQ Reference Date(s) VNT004 Longwall Water Evaporator Vent Waiver P0022664 3/15/2017 CH010 MikroPul 25S-10-20 Baghouse Permit No. P0023144 6/12/2017

PTE Emissions for New Sources

WDEQ Source Operating PM10 NOx Source ID Description Hours (lb/hr) (tons/yr) (lb/hr) (tons/yr) VNT004 Longwall Water Evaporator Vent --- < 0.1 tpy; insignificant ------CH010 MikroPul 25S-10-20 Baghouse 8760 0.2 0.9 ------Subtotal > --- 0.2 0.9 ------

PTE Emissions for New Sources WDEQ Source Operating CO VOC Source ID Description Hours (lb/hr) (tons/yr) (lb/hr) (tons/yr) VNT004 Longwall Water Evaporator Vent ------CH010 MikroPul 25S-10-20 Baghouse 8760 ------Subtotal > ------

Appendix D, Page 4 Appendix E: Characterization of Mobile Sources and Cooling Towers for Modeling

PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 4 EI2 ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory May 10, 2019

COOLING TOWER EMISSION ESTIMATES FOR MODELING

Cooling Tower Flow Rates (V) High Flow (901) 15,000 gal/min Low Flow (902) 5,500 gal/min

Electrical Conductivity (EC) High Flow (901) 4,550 uS/cm Solvay, BO-4 PSD project Low Flow (902) 8,683 uS/cm Solvay, BO-4 PSD project

Total Dissolved Solids (TDS): TDS(ppm) = 0.67 * EC (uS/cm) Source: http://www.stevenswater.com/water_quality_sensors/conductivity_info.html

High Flow (901) 3,048 ppm Low Flow (902) 5,818 ppm

Particulate Emission Rate Estimates, E * E = V(gal/min) x TDS(ppm)/10^6 x Ndrift(%)/100 x Dh2o x 60 min/hr

High Flow (901) Low Flow (902) Reference Cooling Tower flow Rate (V)= 15,000 gal/min 5,500 gal/min Total Dissolved Solids (TDS) = 3,048 ppm 5,818 ppm Drift Loss (Ndrift) = 0.005 % 0.005 % Typical value for towers with drift eliminators. * Density of Water (Dh2o) = 8.34 lb/gal 8.34 lb/gal

* Source: http://www.louisvilleky.gov/NR/rdonlyres/FDCC1304-707F-4A21-A54E-C4CE60990734/0/FormE44WetCoolingTower.pdf

High Flow (901) Low Flow (902) PM Emissions = 1.14 lb/hr 0.80 lb/hr 5.0 tons/year 3.5 tons/year

PM10 Emissions * = 0.46 lb/hr 0.29 lb/hr 2.0 tons/year 1.3 tons/year

PM2.5 Emissions * = 0.070 lb/hr 0.011 lb/hr 0.31 tons/year 0.05 tons/year

* See size fraction calculations on pages 2 and 3.

Blue values are input values and black are calculated values.

Appendix E, Page 1 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 4 EI2 ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory May 10, 2019

COOLING TOWER EMISSION ESTIMATES FOR MODELING, CONTD.

High Flow (901): PM10/PM and PM2.5/PM Mass Fraction Calculations

Reference TDS 3,048 ppm Solvay Calcium Carbonate Density 2.7 g/cc Perry's Chemical Engineer's Handbook, Sixth Edition, p. 3-10. Volume of Sphere V = 4/3*PI*r3

High Flow (901) Water Drop Size Distribution* Droplet Water Droplet Solids Dia. Vol. Mass Mass Vol. Dia. (micron) % mass (cc) (g) (g) (cc) (micron) 22 0.43 5.6E-09 5.6E-09 1.7E-11 6.3E-12 2.3 29 1.49 1.3E-08 1.3E-08 3.9E-11 1.4E-11 3.0 1.9 < (% mass < ~2.5 microns) 44 3.76 4.5E-08 4.5E-08 1.4E-10 5.0E-11 4.6 58 2.09 1.0E-07 1.0E-07 3.1E-10 1.2E-10 6.0 65 1.86 1.4E-07 1.4E-07 4.4E-10 1.6E-10 6.8 87 1.56 3.4E-07 3.4E-07 1.1E-09 3.9E-10 9.1 108 1.43 6.6E-07 6.6E-07 2.0E-09 7.4E-10 11.2 12.6 < (% mass < ~10 microns) 120 1.26 9.0E-07 9.0E-07 2.8E-09 1.0E-09 12.5 132 1.09 1.2E-06 1.2E-06 3.7E-09 1.4E-09 13.7 144 1.32 1.6E-06 1.6E-06 4.8E-09 1.8E-09 15.0 174 5.81 2.8E-06 2.8E-06 8.4E-09 3.1E-09 18.1 300 5.04 1.4E-05 1.4E-05 4.3E-08 1.6E-08 31.2 450** 4.17 4.8E-05 4.8E-05 1.5E-07 5.4E-08 46.9 31.3 < (% mass < 450 microns) Total 31.3

* Effects of Pathogenic and Toxic Material Transport Via Cooling Device Drift - Vol. 1 Technical Report. EPA 600 7-79-251a, Nov. 1979, Pages 59 and 60. ** Maximum droplet size governed by atmospheric dispersion.

High Flow: PM10/PM Mass Fraction = 0.40 High Flow: PM2.5/PM Mass Fraction = 0.06

Appendix E, Page 2 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 4 EI2 ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory May 10, 2019

COOLING TOWER EMISSION ESTIMATES FOR MODELING, CONTD.

Low Flow (902): PM10/PM and PM2.5/PM Mass Fraction Calculations

Reference TDS 5,818 ppm Solvay Calcium Carbonate Density 2.7 g/cc Perry's Chemical Engineer's Handbook, Sixth Edition, p. 3-10. Volume of Sphere V = 4/3*PI*r3

Low Flow (902) Water Drop Size Distribution* Droplet Water Droplet Solids Dia. Vol. Mass Mass Vol. Dia. (micron) % mass (cc) (g) (g) (cc) (micron) 22 0.43 5.6E-09 5.6E-09 3.2E-11 1.2E-11 2.8 0.43 < % mass < ~2.5 microns 29 1.49 1.3E-08 1.3E-08 7.4E-11 2.8E-11 3.7 44 3.76 4.5E-08 4.5E-08 2.6E-10 9.6E-11 5.7 58 2.09 1.0E-07 1.0E-07 5.9E-10 2.2E-10 7.5 65 1.86 1.4E-07 1.4E-07 8.4E-10 3.1E-10 8.4 87 1.56 3.4E-07 3.4E-07 2.0E-09 7.4E-10 11.2 11.2 < % mass < ~10 microns 108 1.43 6.6E-07 6.6E-07 3.8E-09 1.4E-09 13.9 120 1.26 9.0E-07 9.0E-07 5.3E-09 1.9E-09 15.5 132 1.09 1.2E-06 1.2E-06 7.0E-09 2.6E-09 17.0 144 1.32 1.6E-06 1.6E-06 9.1E-09 3.4E-09 18.6 174 5.81 2.8E-06 2.8E-06 1.6E-08 5.9E-09 22.5 300 5.04 1.4E-05 1.4E-05 8.2E-08 3.0E-08 38.7 450** 4.17 4.8E-05 4.8E-05 2.8E-07 1.0E-07 58.1 31.3 < % mass < 450 microns Total 31.3

* Effects of Pathogenic and Toxic Material Transport Via Cooling Device Drift - Vol. 1 Technical Report. EPA 600 7-79-251a, Nov. 1979, Pages 59 and 60. ** Maximum droplet size governed by atmospheric dispersion.

Low Flow: PM10/PM Mass Fraction = 0.36 Low Flow: PM2.5/PM Mass Fraction = 0.01

Appendix E, Page 3 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 4 4 EI2 ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory May 10, 2019

RAILROAD EMISSIONS FOR MODELING

Engines Number Rating (hp) Reference EMD SD40-2 2 3,000 Solvay EMD SD40T-2 1 3,000 Solvay

Operations: 16 hr/day Solvay 6 days/week Solvay 384 hr/month (4 weeks) 4,992 hr/yr Fuel use: 15,000 gal/month Solvay 39.1 gal/hr

Conversion factor: 15.2 bhp-hr/gal Source: Emission Factors for Locomotives; Avg. power based EPA-420-F-09-025, April 2009, Table 3. on Solvay fuel use: 593.8 bhp

Tier 0 Switch Emission Factors (g/bhp-hr) Emissions for Entire Track Length (on and off property); 532 Volume Sources

PM10 0.44 Emiss. Rate CO 1.83 Short-term Per Volume Source: Emission Factors for Locomotives; (lb/hr) (g/sec/vol.)

EPA-420-F-09-025, April 2009, Table 2. PM10, PM2.5 0.58 1.4E-04 CO 2.40 5.7E-04

Track Within SIAs: Short-term Emission Rate for Modeling Track Length: Emiss. Rate Total Length of Track 15.8 km Volumes Per Volume Volumes Along Total Length 532 volumes Pollutant SIA (km) Within SIA (g/sec/vol.)

PM10 ------Conversions

PM2.5 3.8 294 1.4E-04 453.6 grams per lb CO 2.3 192 5.7E-04 3600 sec/hr

Track Within SIAs: Long-term Emission Rate for Modeling Emiss. Rate Volumes Per Volume Pollutant SIA (km) Within SIA (g/sec/vol.)

PM10 ------

PM2.5 3.8 294 7.8E-05

Source Characteristics: Engine Height (H) = 4.8 meters SD40-2 EMD Locomotive Specifications, Solvay, BO-4 PSD project Release Height (H) 1 = 7.13 meters EH *1.5 Solvay, BO-4 PSD project Sigma z (sz) = 3.32 meters Sz = RH/2.15 Width (W) = 8.04 meters Solvay, BO-4 PSD project Sigma y (sy) = 6.53 meters Sy = (W + 6m)/2.15 Number Volumes Along Entire Lenth of Track = 532 vol. sources Solvay, BO-4 PSD project

1 Assume release height is 1.5 times the engine height to account for thermal and buoyant properties of exhaust.

Appendix E, Page 4 Appendix F: Class I Area FLAG Initial Criteria Screening Analysis

March 6, 2019

Project No. 170-18-1

Mr. Nathan Henschel Air Quality Modeler Wyoming Department of Environmental Quality 122 West 25th Street Herschler 2 East Cheyenne, WY 82002

Subject: Class I Area FLAG Initial Screening Criteria Analysis for Solvay Soda Ash Joint Venture Green River, Wyoming Facility – ARGO Production Increase Project

Dear Mr. Henschel:

The Solvay Soda Ash Joint Venture (Solvay) Green River, Wyoming facility proposes several modifications (referred to as project ARGO) to increase soda ash (SA) production. The ARGO project will consist of an additional production line resulting in an increase in the faccility’s total permitted annual production rate from 3.6 MMtpy soda ash to 4.1 MMtpy soda ash. Additional signnificant features of the proposed ARGO project will include the conversion of the existing coal-fired “A” and “B” calciners (Source #17) to natural gas combustion and the coonversion of the existing coal-fired boilers (Sources #18 and #19) to natural gas combustion. All soources will be permitted to operate continuouslyl (8,760 hours per year) at their maximum design rates. Solvay plans to begin construction of the ARGO expansion project in 2020.

This new project will triggg er Prevention of Significant Deterioration (PSD) review for particulate matter

(PM, PM10, and PM2.5), carbon monoxide (CO), and volatile orgaanic compounds (VOC). The project will not triggg er PSD for nitrogen oxides (NOX) or sulfur dioxide (SO2) and will result in a substantial decrease in NOX and SO2 emissions with the conversion of calciiner #17 and boilers #18/#19 from coal combustion to natural gaas combustion. Solvay is not requesting changes to any existing, non-modified source permitted emissions limits (short-term or annual) at the facility; all current permitted emission limits for each source will remain the same after the project.

117 SE T A YLOR S TRE ET, S UITE 302 P ORTLAND , O REGON 97214 503·525·9 394 F AX 5 03·525·94 12

Appendix F, Page 1 Mr. Nathan Henschel March 6, 2019 Page 2 of 9

As discussed with the WyW oming Department of Environmental Quality (WDEQ), Solvay iis providing the attached technical summary of a Class I Area FLAG Initial Screening Criteria analysis for its ARGO project for WDEQ and Federal Land Manager (FLM) review as ppart of the PSD permit application to WDEQ. Please provide this analysis to the appropriate FLMs for their review.

Under the FLAG Initial Screening Criteria methodology, agencies may consider an existinng source located greater than 50 km from a Class I area to have negligible impacts with respect to Class I Air

Quality Related Values (AQRVs), including visibility, if its total annual sulfur dioxide (SO2), NOX,

PM10, and sulfuric acid (H2SO4) emissions in tons per year (Q) from the projeect modification, divided bby the distance in km (D) from the Class I area, are less than 10. Based on the annual emissions from the project modification, the Q/D for the project will be less than 10 for all nearbby Class I areas. Thus, the project would have negligi ible impacts with respect to Class I AQRVs, including visibility, and Solvay would not be required to perform any further Class I AQRV analyses. With this letter, Solvay is requesting a determination of whether this is a sufficient demonstration of negligible AQRV impact on the surrounding Class I areas for this Solvay source modificatioon.

Please contact Tim Brown of Solvay (307-872-6570) or me (971-271-5314) with any questioons you might have regarding this analysis.

Sincerely,

Kent Norville

Tim Martin Senior Air Quality Scientist Air Sciences Inc.

Appendix F, Page 2 Mr. Nathan Henschel March 6, 2019 Page 3 of 9

Class I FLAG Initial Screening Criteria Analysis for the Solvay ARGO Production Increase Project The Solvay Soda Ash Joint Venture (Solvay) Green River, Wyoming facility proposes several modifications (referred to as project ARGO) to increase soda ash (SA) production. The ARGO project will consist of an additional production line, while increasing the facility’s total permitted annual production rate from 3.6 MMtpy soda ash to 4.1 MMtpy soda ash. Additional significant features of the proposed ARGO project will include the conversion of the existting coal-fired “A” and “B” calciners (Source #17) to natural gas combustion and the conversion of the existing coaal-fired boilers (Sources #18 and #19) to natural gas combustion.

As part of the proposed ARGO production expansion project, Solvay wishes to modify the Green River facility by:

 installing a new 200 ton per hour (tph) soda ash product dryer (refer to as DR-8, Source #111),

 installing a new “E” train dryer area baghouse (refer to as Source #110),

 installing a MVR crysstallizer, centrifuges, pumps, and associated piping and making other minor operational and equipment changees to debottleneck productions in other ways,

 convertingn the existingn coal-fired “A” and “B” calciners (Source #17) to natural gas combustion, and increasing the permitted throuughput from 160 tph to 200 tph for each calciner (total of 400 tph for Source #17), (the previously permitted rate when the calciners were natural gas fired),

 convertingn the existingn coal-fired boilers (Sources #18 and #119) to natural gas combustion, and

 increasingn the permitted throughput for the existing DR-6 product dryer (Source #82) from 161 tph soda ash to 200 tph soda ash.

Appendix F, Page 3 Mr. Nathan Henschel March 6, 2019 Page 4 of 9

With the production increase, several sources will be debottlenecked, allowinng an increase in annual production at the facility. Solvay is not requesting changes to anny existing, non-modified source permitted emissions limits (short-term or annual) at the facility;; all current permitted emission limits for each source will remain the same after the projeect.

The sum of the emissions changes from the ARGO project results in a significant net emissions increase of particulate matter (PM, PM10, and PM2.5), carbon monoxide (CO), and volatile organic compounds (VOC), thus triggering Prevention of Significant Deterioration (PSD) review. The project will not trigger PSD for nitrogen oxides (NOX) or sulfur dioxide (SO2) and will result in a substantial decrease in

NOX and SO2 emissions with the conversion of calciner #17 and boilers #18//#19 from coal combustion to natural gas combustion.

This report provides a preliminary summary of the Class I area screening procedure, as outlined in the Federal Land Managers’ (FLM) Air Quality Related Values (AQRV) Work Group (FLAG) Phase I Report—Revised (2010).1

The Solvay facility is located in Section 31, T18N, R109W, approximately 20 miles west of the town of Green River, in Sweetwater County, WyW oming, as shown in Figure 1. The facility is located at 41.502˚N latitude and 109.757˚W longitude, which corresponds to 603.7 km Easting and 4,594.8 km Northing (zone 12) in the Universal Transverse Mercator (UTM) 1927 North American Datum (NAD27) system. Figure 2 shows a view of the facility.

1 Natural Resource Report NPS/NRPC/NRR—2010/232; https://irma.nps.gov/DataStore/Reference/Profile/2125044

Appendix F, Page 4 Mr. Nathan Henschel March 6, 2019 Page 5 of 9

Figure 1. Solvay Facility Location on a Regional Scale Map

Appendix F, Page 5 Mr. Nathan Henschel March 6, 2019 Page 6 of 9

Figure 2. View of Solvay Facility

FLAG Initial Screening Criteria Methodology Under the FLAG Initial Screening Criteria methodology, agencies will consider an existinng source located greater than 50 km from a Class I area to have negligible impacts with respect to Class I

AQRVs, including visibility, if its total annual sulfur dioxide (SO2), NOX, PM10, and sulfuric acid

(H2SO4) emissions in tons per year (Q) from the projo ect modification, divided by the distance in km (DD) from the Class I area, are less than 10. The total emissions fromm the modification must be based on the maximum allowable 24-hour emission rates, assuming continuous (e.g., 365 days/year) operation.

Figure 3 shows the location of the Class I areas with respect to the Solvay facility. All Class I areas are located greater than 50 kilometers (km) from the Solvay facility. Although it is not one of the 156 Federal Class I areas, the State of Wyooming has declared that the Savage Run Wilderness area must be managed as a Class I area; therefore, this wilderness area was also included in the Class I area screening analysis.

Appendix F, Page 6 Mr. Nathan Henschel March 6, 2019 Page 7 of 9

Figure 3. Location of Class I Areas within 300 Kilometers of the Solvay Facility

Project Emissions Table 1 shows the anticipated project emissions. Annual emission rates are based on the maximum hourly rate applied over the entire year (8,760 hours/year). Emissions of H2SO4 from the project are insignificant and are not considered further. FLAG’s requirement to include allowable NOx and SO2 emissions in this analysis are conservative since the ARGO project will result in a substantial decrease in NOx and SO2 emissions at the facility. The NOx and SO2 emissions presented in the analysis are the post-project maximum allowable emissions.

Appendix F, Page 7 Mr. Nathan Henschel March 6, 2019 Page 8 of 9

Table 1. Solvay ARGO Project Anticipated Emission Rates for PM10, SO2, and NOX

Maximum Allowable Emissions WDEQ PM SO NOx Source 10 2 ID Source Description (lb/hrr) (TPY) (lb/hr) (TPY) (lb/hr) (TPY) 111 New DR-8 Product Dryer 3..7 16.1 0.1 0.5 30.0 131.4 110 New “E” Train Dryer Area Baghouse 1..4 6.0 17 "A" and "B" Calciners (converted to NG) 22.0 96.4 14.4 63.1 18 #1 Boiler (converted to NG) 2..9 12.6 0.2 1.0 9.3 40.7 19 #2 Boiler (converted to NG) 2..9 12.6 0.2 1.0 9.3 40.7 2A Ore Crusher Building 1.660 7.0 06A Product Silos-Top 0.330 1.3 06B Product Silos- Bottom #1 0.551 2.2 7 Product Loadout Station 1.20 5.3 15 DR-1 & 2 Steam Tube Dryers 3.000 13.1 1.8 7.9 16 Dryer Area 0.990 3.9 46 Ore Transfer Station 0.71 3.1 48 "C" Calciner 8.000 35.0 15.0 65.7 50 "C" Train Dryer Area 0.70 3.1 51 Product Dryeer #5 2.440 10.5 0.1 0.4 18.0 78.8 52 Product Silo- Top #2 0.550 2.2 53 Product Silo- Bottom #2 0.445 2.0 76 "D" Train Primary Ore Screening 2.445 10.7 79 Ore Transfer Point 0.884 3.7 80 "D" Ore Calciner 10.00 43.8 20.0 87.6 81 "D" Train Dryer Area 0.550 2.2 82 DR-6 Product Dryer 3.445 15.1 0.1 0.5 30.0 131.4 99 Crusher Baghhouse #2 3.20 14.0 103 East Ore Reclaim Baghouse 0.333 1.4 104 West Ore Reclaim Baghouse 0.27 1.2 109 Gas-fired Package Boiler 1.889 8.3 0.15 0.7 2.8 12.3 Totals > --- 332.9 --- 4.1 --- 659.5

Appendix F, Page 8 Mr. Nathan Henschel March 6, 2019 Page 9 of 9

Results

Based on the emission rates from Table 1, the sum of the maximum annual PM10, SO2, and NOX emission rates is 996 TPY. Table 2 shows the Q/D calculations for all Class I areas within 300 km of Solvay. At all Class I areas, the Q/D is less than 10; thus, the Solvay project will have negligible impacts on visibility and other AQRVs, and Solvay is not required to perform any further Class I AQRV analyses.

Table 2. Q/D Calculations for Class I Areas within 300 Kilommeters of Solvay

Class I Area Agency D (km) Q/D Less than 10? Bridger Wilderness USFS 131 7.6 Yes Fitzpatrick Wilderness USFS 167 6.0 Yes Grand Teton NP NPS 240 4.2 Yes Washakie Wilderness USFS 245 4.1 Yes Teton Wilderness USFS 251 4.0 Yes Mt. Zirkel Wilderness USFS 251 4.0 Yes Flat Tops Wilderness USFS 255 3.9 Yes Savage Run Wilderness WY 277 3.6 Yes Yellowstone NP NPS 293 3.4 Yes Arches NP NPS 295 3.4 Yes

Appendix F, Page 9 Appendix G: Emission Calculations for Health Risk Assessment

PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 3 Project Toxics ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 28, 2019

NEW DRYER (DR-8) AND DEBOTTLENECKED SOURCES: TOXIC EMISSION FACTORS AND INPUTS AND TOXICITY INFORMATION

Gas EF Gas EF Dose Response Risk Factor Pollutant Reference (lb/106 scf) (lb/MMBtu) * Chronic Cancer - Inhalation (1/g/m3) ** Arsenic ARS 2.00E-04 1.96E-07 0.0043 Benzene BZN 2.10E-03 2.06E-06 0.0000078 Benzo(a)anthracene BZA 1.80E-06 1.76E-09 0.00006 Benzo(a)pyrene BZP 1.20E-06 1.18E-09 0.0006 Benzo(b)fluoranthene BBF 1.80E-06 1.76E-09 0.00006 Benzo(k)fluoranthene BZF 1.80E-06 1.76E-09 0.000006 Beryllium BER 1.20E-05 1.18E-08 0.0024 Cadmium CAD 1.10E-03 1.08E-06 0.0018 Chrysene CHR 1.80E-06 1.76E-09 0.0000006 Dibenzo(a,h)anthracene DIB 1.20E-06 1.18E-09 0.0006 7,12-Dimethylbenz(a)anthracene DIM 1.60E-05 1.57E-08 0.071 Formaldehyde FRM 7.50E-02 7.35E-05 0.000013 Indeno(1,2,3-cd)pyrene IND 1.80E-06 1.76E-09 0.00006 3-Methylcholanthrene MTH 1.80E-06 1.76E-09 0.0063 Naphthalene NAP 6.10E-04 5.98E-07 0.000034

Gas emission factors from AP-42, Section 1.4 - "Natural Gas Combustion," Tables 1.4.3 and 1.4-4 (Revision 7/98). * Per AP-42, Section 1.4, Table 1.4-2, to convert the AP-42 emission factors in lb/MMscf to lb/MMBtu divide by 1020.

** EPA Air Toxics Website, accessed 3/28/2019: https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants

Assumptions Reference Natural gas thermal equivalent 1,020 Btu/scf AP-42, Section 1.4 (Revision 7/98)

Conversions 453.59 g/lb 2000 lb/ton 2.20462 lb/kg 8760 hr/yr 3600 sec/hr 453.6 g/lb

Blue are input values and black are calculated values.

Appendix G, Page 1 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 3 Project Toxics ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 28, 2019

NEW DRYER AND DEBOTTLENECKED SOURCES: MAXIMUM THROUGHPUTS/RATINGS

WDEQ Max. Rating Gas Usage Source ID Source Description Fuel Hours (MMBtu/hr) (MMBtu/yr) 111 DR-8 Product Dryer Gas 8760 200 1,752,000 15 DR-1 & 2 Steam Tube Dryers None* ------17 "A" and "B" Calciners Gas 8760 400 3,504,000 18 #1 Boiler (converted to NG) Gas 8760 387 3,390,120 19 #2 Boiler (converted to NG) Gas 8760 387 3,390,120 48 "C" Calciner Gas 8760 250 2,190,000 51 Product Dryer #5 Gas 8760 150 1,314,000 80 "D" Calciner Gas 8760 400 3,504,000 82 DR-6 Product Dryer Gas 8760 200 1,752,000 109 Gas-fired Package Boiler Gas 8760 254 2,225,040 * Source #15 fed by heat from boiler only, old preheaters on Source #15 are no longer used.

NEW DRYER AND DEBOTTLENECKED SOURCES: TOXIC EMISSION CALCULATIONS

Annual PTE (tpy) Pollutant Reference #111 #17 #18 #19 #48 #51 #80 #82 #109 Total Arsenic ARS 1.72E-04 3.44E-04 3.32E-04 3.32E-04 2.1E-04 1.3E-04 3.4E-04 1.7E-04 2.2E-04 2.26E-03 Benzene BZN 1.80E-03 3.61E-03 3.49E-03 3.49E-03 2.3E-03 1.4E-03 3.6E-03 1.8E-03 2.3E-03 2.37E-02 Benzo(a)anthracene BZA 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 2.0E-06 2.03E-05 Benzo(a)pyrene BZP 1.03E-06 2.06E-06 1.99E-06 1.99E-06 1.3E-06 7.7E-07 2.1E-06 1.0E-06 1.3E-06 1.35E-05 Benzo(b)fluoranthene BBF 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 1.96E-06 2.03E-05 Benzo(k)fluoranthene BZF 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 2.0E-06 2.03E-05 Beryllium BER 1.03E-05 2.06E-05 1.99E-05 1.99E-05 1.3E-05 7.7E-06 2.1E-05 1.0E-05 1.3E-05 1.35E-04 Cadmium CAD 9.45E-04 1.89E-03 1.83E-03 1.83E-03 1.2E-03 7.1E-04 1.9E-03 9.4E-04 1.2E-03 1.24E-02 Chrysene CHR 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 2.0E-06 2.03E-05 Dibenzo(a,h)anthracene DIB 1.03E-06 2.06E-06 1.99E-06 1.99E-06 1.3E-06 7.7E-07 2.1E-06 1.0E-06 1.3E-06 1.35E-05 7,12-Dimethylbenz(a)anthracene DIM 1.37E-05 2.75E-05 2.66E-05 2.66E-05 1.7E-05 1.0E-05 2.7E-05 1.4E-05 1.7E-05 1.81E-04 Formaldehyde FRM 6.44E-02 1.29E-01 1.25E-01 1.25E-01 8.1E-02 4.8E-02 1.3E-01 6.4E-02 8.2E-02 8.46E-01 Indeno(1,2,3-cd)pyrene IND 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 2.0E-06 2.03E-05 3-Methylcholanthrene MTH 1.55E-06 3.09E-06 2.99E-06 2.99E-06 1.9E-06 1.2E-06 3.1E-06 1.5E-06 2.0E-06 2.03E-05 Naphthalene NAP 5.24E-04 1.05E-03 1.01E-03 1.01E-03 6.5E-04 3.9E-04 1.0E-03 5.2E-04 6.7E-04 6.88E-03

Appendix G, Page 2 PROJECT TITLE: BY: Air Sciences Inc. Solvay - ARGO Production Increase T. Martin PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 3 Project Toxics ENGINEERING CALCULATIONS SUBJECT: DATE: Emissions Inventory March 28, 2019

NEW DRYER (DR-8) AND DEBOTTLENECKED SOURCES: TOXICITY-WEIGHTED SCREENING FOR CARCINOGENIC HAPs

X = Total Y = Dose Response Emissions Risk Factor Percent of Cumulative Pollutant Reference (tpy) (1/g/m3) ** X * Y Total (X * Y) (%) Cadmium CAD 1.24E-02 0.0018 2.23E-05 39.4% 39.4% 7,12-Dimethylbenz(a)anthracene DIM 1.81E-04 0.071 1.28E-05 22.6% 61.9% Formaldehyde FRM 8.46E-01 0.000013 1.10E-05 19.4% 81.3% Arsenic ARS 2.26E-03 0.0043 9.71E-06 17.1% 98.4% Beryllium BER 1.35E-04 0.0024 3.25E-07 0.6% 99.0% Naphthalene NAP 6.88E-03 0.000034 2.34E-07 0.4% 99.4% Benzene BZN 2.37E-02 0.0000078 1.85E-07 0.3% 99.7% 3-Methylcholanthrene MTH 2.03E-05 0.0063 1.28E-07 0.2% 100.0% Dibenzo(a,h)anthracene DIB 1.35E-05 0.0006 8.13E-09 0.01% 100.0% Benzo(a)pyrene BZP 1.35E-05 0.0006 8.13E-09 0.01% 100.0% Benzo(a)anthracene BZA 2.03E-05 0.00006 1.22E-09 0.002% 100.0% Indeno(1,2,3-cd)pyrene IND 2.03E-05 0.00006 1.22E-09 0.002% 100.0% Benzo(b)fluoranthene BBF 2.03E-05 0.00006 1.22E-09 0.002% 100.0% Benzo(k)fluoranthene BZF 2.03E-05 0.000006 1.22E-10 0.0002% 100.0% Chrysene CHR 2.03E-05 0.0000006 1.22E-11 0.00002% 100.0% ** EPA Air Toxics Website, accessed 8/8/2018: https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants

NEW DRYER (DR-8) AND DEBOTTLENECKED SOURCES: TOXIC EMISSION CALCULATIONS FOR MODELED HAPs

WDEQ Annual Emissions for Modeling (g/sec) Source ID Source Description CAD DIM FRM ARS 111 DR-8 Product Dryer 2.72E-05 3.95E-07 1.85E-03 4.94E-06 17 "A" and "B" Calciners 5.44E-05 7.91E-07 3.71E-03 9.88E-06 18 #1 Boiler (converted to NG) 5.26E-05 7.65E-07 3.59E-03 9.56E-06 19 #2 Boiler (converted to NG) 5.26E-05 7.65E-07 3.59E-03 9.56E-06 48 "C" Calciner 3.40E-05 4.94E-07 2.32E-03 6.18E-06 51 Product Dryer #5 2.04E-05 2.96E-07 1.39E-03 3.71E-06 80 "D" Calciner 5.44E-05 7.91E-07 3.71E-03 9.88E-06 82 DR-6 Product Dryer 2.72E-05 3.95E-07 1.85E-03 4.94E-06 109 Gas-fired Package Boiler 3.45E-05 5.02E-07 2.35E-03 6.28E-06 Totals >> 3.57E-04 5.19E-06 2.43E-02 6.49E-05

Appendix G, Page 3

Appendix H: Best Available Control Technology Review

Best Available Control Technology Review

ARGO Project

PREPARED FOR: SOLVAY SODA ASH JV

PROJECT NO. 170-18-1 MAY 9, 2019

Appendix H, Page 1

TABLE OF CONTENTS

List of Abbreviations ...... 4 1.0 BACT Applicability ...... 5 1.1 Emission Units Subject to PSD BACT or State-Only BACT ...... 6 2.0 PSD BACT Review ...... 7 2.1 Calciners ...... 7 2.1.1 CO ...... 8 2.1.2 Particulates...... 8 2.1.3 VOC ...... 9 2.1.4 GHG ...... 10 2.2 Natural Gas-Fired Boilers ...... 11 2.2.1 CO ...... 11 2.2.2 Particulates...... 12 2.2.3 VOC ...... 13 2.2.4 GHG ...... 13 2.3 Soda Ash Product Crushing, Screening, and Transfers ...... 13 2.3.1 Particulates...... 14 2.4 Product Dryer ...... 15 2.4.1 CO ...... 15 2.4.2 Particulates...... 16 2.4.3 VOC ...... 16 2.4.4 GHG ...... 17 3.0 State-Only BACT ...... 18 3.1 CO, Particulates, VOC, and GHG ...... 18

3.2 SO2 ...... 18

3.3 NOX ...... 19 4.0 References ...... 20

Tables Table 1-1. Net Emission Increase ...... 5 Table 1-2. Sources and Pollutants Requiring a PSD BACT Review ...... 6 Table 1-3. Sources and Pollutants Requiring a State-Only BACT ...... 6

Appendix H, Page 2 Table 2-1. CO Control Options for Source #17 ...... 8 Table 2-2. PM Control Options for Source #17 ...... 9 Table 2-3. VOC Control Options for Source #17 ...... 9 Table 2-4. GHG Control Options for Source #17 ...... 10 Table 2-5. CO Control Options for Sources #18 and #19 ...... 11 Table 2-6. PM Control Options for Sources #18 and #19 ...... 12 Table 2-7. VOC Control Options for Sources #18 and #19 ...... 13 Table 2-8. GHG Control Options for Sources #18 and #19 ...... 13 Table 2-9. PM Control Options for Sources #81 and #110 ...... 14 Table 2-10. CO Control Options for Source #111 ...... 15 Table 2-11. PM Control Options for Source #111 ...... 16 Table 2-12. VOC Control Options for Sources #82 and #111 ...... 17 Table 2-13. GHG Control Options for Sources #82 and #111 ...... 17 Table 3-1. State-Only BACT for CO, Particulates, VOC, and GHG ...... 18 Table 3-2. Sources and Pollutants Requiring a State-Only BACT ...... 19 Table 3-3. Sources and Pollutants Requiring a State-Only BACT ...... 19

Attachments Attachment H 1 – Net Emissions Increase Calculations Attachment H 2 – RBLC Search Downloads Attachment H 3 – BACT Cost Calculations

Appendix H, Page 3

LIST OF ABBREVIATIONS

BACT Best Available Control Technology Btu British Thermal Unit CCS Carbon Capture and Sequestration CFR Code of Federal Regulations CO Carbon Monoxide

CO2 Carbon Dioxide

CO2e Carbon Dioxide Equivalent dscf Dry Standard Cubic Foot dscfm Dry Standard Cubic Feet per Minute EPA U.S. Environmental Protection Agency ESP Electrostatic Precipitator GHG Greenhouse Gas gr Grain LAER Lowest Achievable Emission Rate lb Pound MMBtu Million British Thermal Units

NOX Oxides of Nitrogen NSPS New Source Performance Standards

O3 Ozone PM Particulate Matter

PM2.5 Particulate Matter Less than 2.5 Microns in Diameter

PM10 Particulate Matter Less than 10 Microns in Diameter RACT Reasonably Available Control Technology RBLC RACT/BACT/LAER Clearinghouse RTO Regenerative Thermal Oxidation scf Standard Cubic Foot scfm Standard Cubic Feet per Minute VOC Volatile Organic Compound WAQSR Wyoming Air Quality Standards and Regulations WDEQ Wyoming Department of Environmental Quality

Appendix H, Page 4

1.0 BACT APPLICABILITY

The Solvay ARGO project will result in the modification of existing emission units and the addition of new emission units. The Solvay facility is an existing major stationary source. The ARGO project will result in a significant increase in emissions subject to the Prevention of Significant Deterioration (PSD) regulations per Chapter 6, Section 4 of the Wyoming Air Quality Standards and Regulations (WAQSR). Therefore, the project is subject to a Best Available Control Technology (BACT) review under Section 4(b)(ii) for each pollutant with a significant emission increase.

Table 1-1 provides the net emission increase of each pollutant compared to the significant level. As shown in Table 1-1, a BACT review is required for carbon monoxide (CO), particulate matter

(PM), particulate matter measuring less than 10 microns in diameter (PM10), particulate matter measuring less than 2.5 microns in diameter (PM2.5), ozone (O3), and greenhouse gases (GHG). The net emission increases shown in this table are based on the increase from the baseline actual emissions to the projected actual emissions for all existing sources with the potential to be debottlenecked, and the baseline actual emissions to the potential emissions of all new and modified sources. The small amounts of contemporaneous increases and decreases (0.9 tons per year of PM) are also included in Table 1-1. The emission calculations are provided in Attachment H1.

Table 1-1. Net Emission Increase

Net Emission Significant Level Pollutant Increase (ton/yr)(1) BACT Required

CO 10,463 100 Yes

(2) NOX -615 40 No

PM2.5 103 10 Yes

PM10 103 15 Yes

PM 103 25 Yes

(2) SO2 -44 40 No 2,331 VOC 40 O3 Yes -615 NOX (VOC or NOX) Pb(3) 0.0056 0.6 No

(4) CO2e 1,048,932 75,000 Yes (1) WAQSR Chapter 6, Section 4(a), “Significant.” (2) For a maximum-case net emission increase analysis, the NOX and SO2 emission increases are based on the baseline actual emissions to the potential emissions of all new, modified, and debottlenecked sources. (3) Emissions of Pb represent ARGO project potential emissions. (4) WAQSR Chapter 6, Section 4(a), “Greenhouse gases (GHGs),” Paragraph (iii))(B).

Appendix H, Page 5

In addition to the BACT requirements under the PSD regulations (WAQSR Chapter 6, Section 4), new and modified sources are also subject to BACT under WAQSR Chapter 6, Section 2(c)(v), referred to herein as State-Only BACT.

1.1 Emission Units Subject to PSD BACT or State-Only BACT

The pollutants emitted in significant amounts requiring a PSD BACT review are CO, PM, PM10,

PM2.5, O3 (volatile organic compound [VOC]), and GHG. The emission units undergoing a physical change or a change in the method of operation as part of the proposed ARGO project are listed in Table 1-2, along with the emitted pollutants requiring a PSD BACT review.

Table 1-2. Sources and Pollutants Requiring a PSD BACT Review

Source New or ID Source Description Modified PSD BACT Pollutants

CO, PM, PM10, PM2.5, O3 (VOC), and 17 "A" and "B" Calciners Modified GHG

CO, PM, PM10, PM2.5, O3 (VOC), and 18 #1 Natural Gas-Fired Boiler Modified GHG

CO, PM, PM10, PM2.5, O3 (VOC), and 19 #2 Natural Gas-Fired Boiler Modified GHG

110 "E" Train Dryer Area New PM, PM10, and PM2.5

CO, PM, PM10, PM2.5, O3 (VOC), and 111 DR-8 Product Dryer New GHG

Table 1-3 lists the sources and pollutants subject to State-Only BACT that are not already subject to PSD BACT in Table 1-2 above.

Table 1-3. Sources and Pollutants Requiring a State-Only BACT

Source New or ID Source Description Modified State-Only BACT Pollutants

17 "A" and "B" Calciners Modified SO2 and NOX

18 #1 Natural Gas-Fired Boiler Modified SO2 and NOX

19 #2 Natural Gas-Fired Boiler Modified SO2 and NOX Throughput 81 "D" Train Dryer Area PM, PM10, and PM2.5 Limit Increase(1)

Throughput SO2, NOX, CO, PM, PM10, PM2.5, O3 82 DR-6 Product Dryer Limit Increase(1) (VOC), and GHG

110 "E" Train Dryer Area New PM, PM10, and PM2.5

111 DR-8 Product Dryer New SO2 and NOX

(1) Solvay is proposing to increase the permitted throughput limit from 160 to 200 tons per hour. This change to the permit limit does not require a physical change or a change in the method of operation of the emission unit equipment, nor does it require a change to any of the permitted emission limits. Therefore, it is not subject to PSD BACT, as discussed with the Wyoming Department of Environmental Quality (WDEQ) on February 28, 2019 (WDEQ and Solvay 2019).

Appendix H, Page 6

2.0 PSD BACT REVIEW

This section provides a PSD BACT review for each emission unit and pollutant described in Section 1.1, Table 1-2. The BACT review process requires the determination of BACT on a case- by-case basis, including a consideration of the unique aspects of each emission unit. The following sections contain the required review and BACT determination using the guidelines from Chapter B of the U.S. Environmental Protection Agency (EPA) guidance document, New Source Review Workshop Manual, Prevention of Significant Deterioration and Nonattainment Area Permitting, Draft (EPA 1990). The review was conducted using the following five steps:

1. Identification of all possible control technologies

2. Elimination of technologically infeasible technologies

3. Ranking of the technologies by control effectiveness

4. Evaluation of the most effective control technology with consideration of economic, energy, and environmental impacts

5. Selection of BACT

The proposed BACT determinations provided herein for the ARGO project sources are compared to the applicable New Source Performance Standards (NSPS): “the only reason for comparing control options to an NSPS is to determine whether the control option would result in an emissions level less stringent than the NSPS. If so, the option is unacceptable” (EPA 1990).

Each of the following sections provides a BACT review for the sources listed in Table 1-2. The search results downloaded from the EPA RACT/BACT/LAER Clearinghouse (RBLC) (EPA 2019) and used for Step 1 are provided in Attachment H2. Control technology cost-effectiveness calculations used for Step 4 are provided in Attachment H3. However, when the top (most effective) control option is selected as BACT, no cost data are provided per EPA’s guidance: “an applicant proposing the top control alternative need not provide cost and other detailed information in regard to other control options” (EPA 1990).

2.1 Calciners Source #17, that is, the "A" and "B" Calciners, will be converted from coal to natural gas, and the throughput will be increased for each from 160 to 200 tons per hour. These calciners are not subject to an NSPS standard under 40 Code of Federal Regulations (CFR) 60. The BACT

emissions reviews of CO, PM, PM10, PM2.5, O3 (VOC), and GHG from these calciners are provided in the following subsections.

Emission control technologies for the Calciners were obtained from the RBLC. The RBLC was searched for all determinations in the last 10 years under the process name/description

Appendix H, Page 7

containing the keywords “kiln” or “calciner.” The downloaded records were then further filtered as follows:

• PROCESS_NAME: Contains “kiln” or “calciner”

• PROCESS_TYPE: 90 to 90.999, Mineral Products

• PRIMARY_FUEL: Contains “natural gas” or “nat gas”

• CASE-BY-CASE_BASIS: BACT-PSD

2.1.1 CO The results of the RBLC search for pollutant “carbon monoxide” are summarized in Table 2-1.

Table 2-1. CO Control Options for Source #17

Number of Emission Limit Control Technology Determinations (lb/ton) Good Combustion Practices 7 1.3 to 4.22

An additional control option not found in the RBLC search is the Regenerative Thermal Oxidizer (RTO). Typical applications of RTOs are for emission units with exhaust flow rates of 10,000 to 100,000 standard cubic feet per minute (scfm) (EPA 2017). The exhaust rate from Source #17 is 170,600 scfm, which is significantly beyond this range. Furthermore, there are no RTOs installed on any of the trona calciners (four facilities) in the southwest Wyoming trona patch. Therefore, it can be inferred that this control option is not considered technically feasible and/or cost-effective for trona calciners. The total capital investment for an RTO system for System #17 is approximately $12 million.1 At this cost, an RTO is not considered cost-effective.

Solvay proposes using good combustion practices as BACT control for CO emissions from Source #17. The resulting BACT CO emission rate is 3.81 lb/ton.

The capital costs, energy costs, and environmental impacts of using good combustion practices are minimal.

2.1.2 Particulates The results of the RBLC search for pollutant “particulate” are summarized in Table 2-2. For the determinations that included more than one emission limit (i.e., separate emission limits for

PM, PM10, and PM2.5), only the unique PM limits are shown in Table 2-2 to avoid duplicate control determinations.

1 This cost is based on Section 3.2, Chapter 2, Equation 2.33 and Table 2.10 of the EPA Control Cost Manual (EPA 2017) for an exhaust flow rate of 170,600 dscfm from Source #17. The 1988-dollar values from this equation were converted to 2019 dollars by multiplying by 2.14.

Appendix H, Page 8

Table 2-2. PM Control Options for Source #17

Number of Emission Limit Control Technology Determinations (gr/dscf) Baghouse 7 0.009 to 0.01

ESP 2 0.006 to 0.012

An additional control option not found in the RBLC search is a wet scrubber. Control effectiveness rankings for the possible control technologies, from highest to lowest, are (1) baghouse, (2) electrostatic precipitator (ESP), and (3) wet scrubber.2 However, based on the RBLC download for calciners, as shown in Table 2-2, it appears that the levels of control achieved by a baghouse and an ESP are comparable. Furthermore, there are no baghouses installed on any of the trona calciners (four facilities) in the southwest Wyoming trona patch. Therefore, it can be inferred that this control option is not considered technically feasible and/or cost-effective for trona calciners.

Solvay proposes an ESP for Source #17 as BACT to reduce particulate emissions. The resulting

BACT particulate (i.e., PM, PM10, and PM2.5) emission rate is 0.015 grains per dry standard cubic foot (gr/dscf).

Costs associated with an ESP include those pertaining to electricity and maintenance. Environmental impacts from an ESP are minimal as it does not generate waste.

2.1.3 VOC The results of the RBLC search for pollutant “volatile organic compounds” are summarized in Table 2-3.

Table 2-3. VOC Control Options for Source #17

Number of Emission Limit Control Technology Determinations (lb/ton) Good Combustion 5 0.1 Practices(1) (1) Including determinations where: 1) no control is specified and 2) the use of clean gaseous fuels.

An additional control option not found in the RBLC search is the RTO. Typical applications of RTOs are for emission units with exhaust flow rates of 10,000 to 100,000 scfm (EPA 2017). The exhaust rate from Source #17 is 170,600 scfm, which is significantly beyond this range. Furthermore, there are no RTOs installed on any of the trona calciners (four facilities) in the southwest Wyoming trona patch. Therefore, it can be inferred that this control option is not considered technically feasible and/or cost-effective for trona calciners. The estimated total

2 AP-42, Fifth Edition (EPA 1995) provides control efficiencies for these emission control technologies.

Appendix H, Page 9

capital investment for an RTO system for System #17 is approximately $12 million.3 At this cost, an RTO is not considered cost-effective.

Solvay proposes converting to natural gas and using good combustion practices as BACT control for VOC emissions from Source #17. The resulting BACT VOC emission rate is 1.7 lb/ton. In addition, Solvay shall follow sound mining/roof control practices to minimize shale in the trona ore. All mining crews will receive annual training regarding sound mining/roof control practices.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal.

2.1.4 GHG The results of the RBLC search for pollutant “carbon dioxide” are summarized in Table 2-4.

Table 2-4. GHG Control Options for Source #17

Number of Emission Limit Control Technology Determinations (lb/ton) Good Combustion Practices 5 1 to 436

A possible add-on control option for GHG is carbon capture and sequestration (CCS). Carbon

sequestration is a geo-engineering technique used to remove the CO2 from an exhaust gas stream and store it permanently in underground reservoirs (i.e., typically depleted oil or gas reservoirs) or other geological features. The technology captures CO2 before it enters the atmosphere, compresses it to a near liquid state, and transports it via pipelines to a site where it

is injected deep underground. The deep geological formations that receive and hold CO2 must

be far below fresh water aquifers and below an impermeable rock cap or seal so that CO2 cannot contaminate potable groundwater or escape to the atmosphere. Alternative sequestration

techniques include converting CO2 to baking soda or algae-based carbon capture. The long-term storage of CO2 is a relatively new concept and has mostly been demonstrated on a pilot scale. Transport and storage challenges include a lack of existing infrastructure (e.g., pipelines) and

sites for secure, long-term CO2 storage.

CCS is an emerging technology that has had limited successful applications on an industrial scale. There are currently no CCS systems commercially available for full-scale operations in the United States. For BACT purposes, it is considered an innovative control option: “Innovative controls that have not been demonstrated on any source type similar to the proposed source need not be considered in the BACT analysis” (EPA 1990).

3 These costs are based on Section 3.2, Chapter 2, Equation 2.33 and Table 2.10 of the EPA Control Cost Manual (EPA 2017) for an exhaust flow rate of 170,600 dscfm from Source #17. The 1988-dollar values from this equation were converted to 2019 dollars by multiplying by 2.14.

Appendix H, Page 10

Solvay proposes converting to natural gas and using good combustion practices as BACT

control for GHG emissions from Source #17. The resulting BACT GHG (CO2e) emission rate is 400 lb/ton, based on EPA’s AP-42, Table 8.12-4, Monohydrate.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal.

2.2 Natural Gas-Fired Boilers Sources #18 and #19 will be converted from coal to natural gas. These boilers have a rated heat input of 387 MMBtu/hr, HHV (350 MMBtu/hr, LHV) and are subject to 40 CFR 60, Subpart D.

The BACT emissions reviews of CO, PM, PM10, PM2.5, O3 (VOC), and GHG from these boilers are provided in the following subsections.

The emission control technologies for the Natural Gas-Fired Boilers were obtained from the RBLC. The RBLC was searched for all determinations in the last 10 years under process code 11, Utility- and Large Industrial-Sized Boilers/Furnaces (>250 million BTU/H) and subcategory 11.310 Natural Gas (including propane and liquefied petroleum gas). The downloaded records were then further filtered as follows:

• PROCESS_NAME: Contains “boiler”

• PROCCESS_TYPE: 11.31

• PRIMARY_FUEL: Contains “natural gas” or “nat gas”4

• CASE-BY-CASE_BASIS: BACT-PSD

2.2.1 CO The results of the RBLC search for pollutant “carbon monoxide” are summarized in Table 2-5.

Table 2-5. CO Control Options for Sources #18 and #19

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Oxidation Catalyst 1 0.0013 Good Combustion 42 0.0013 to 0.47 Practices(1) (1) Including determinations where no control is specified.

As shown in Table 2-5, a possible add-on control option for Sources #18 and #19 is a catalytic oxidizer. However, because there is only one out of 43 BACT determinations in the RBLC for this add-on control option, and it is for a larger boiler (456 MMBtu/hr), it can be inferred that

4 RBLC ID CT-0156 was excluded as it is a biomass boiler.

Appendix H, Page 11

this control option is not cost-effective for Sources #18 and #19. The potential annual CO emissions from Sources #18 and #19 based on 8,760 hours of operation are 125 tons per year per unit. The total capital investment for a catalytic oxidizer is approximately $3 million per unit.5 At this capital cost, the total annual cost is estimated at $1 million per year per unit.6 This yields a cost-effectiveness of $9,558 per ton of CO removed (assuming 90 percent removal), which is not considered cost-effective.

Solvay proposes converting to natural gas and using good combustion practices as BACT control for CO emissions from Sources #18 and #19. The resulting BACT CO emission rate for Sources #18 and #19 is 0.074 lb/MMBtu.

The capital costs, energy costs, and environmental impacts of using good combustion practices are minimal. There is no NSPS CO emission standard under 40 CFR 60, Subpart D.

2.2.2 Particulates The results of the RBLC search for pollutant “particulate” (excluding “particulate matter, fugitive”) are summarized in Table 2-6. For determinations that included more than one

emission limit (i.e., separate emission limits for PM, PM10, and PM2.5), only the unique PM limits are shown in Table 2-6 to avoid duplicate control determinations.

Table 2-6. PM Control Options for Sources #18 and #19

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 40 0.001 to 0.01 Practices(1) (1) Including determinations where: 1) no control is specified and 2) the use of clean gaseous fuels.

As shown in Table 2-6, all of the determinations are for good combustion practices and/or the use of clean gaseous fuels. The combustion of natural gas is the cleanest form of fossil-fuel combustion in terms of particulate emissions. Solvay proposes converting to natural gas and using good combustion practices as BACT control for PM emissions from Sources #18 and #19. The resulting BACT PM emission rates for Sources #18 and #19 are 0.0075 lb/MMBtu each.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal. There is no NSPS PM emission standard under 40 CFR 60, Subpart D.

5 This cost is based on Section 3.2, Chapter 2, Equation 2.37 of the EPA Control Cost Manual (EPA 2017) for an exhaust flow rate of 76,425 dscfm from Sources #18 and #19. The 1988-dollar values from this figure were converted to 2019 dollars by multiplying by 2.14. 6 Equipment costs were used to estimate the total annual costs using the example provided in Section 3.2, Chapter 2, Tables 2.11 and 2.12 of the EPA Control Cost Manual (EPA 2017).

Appendix H, Page 12

2.2.3 VOC The results of the RBLC search for pollutant “volatile organic compounds” are summarized in Table 2-7.

Table 2-7. VOC Control Options for Sources #18 and #19

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 29 0.0014 to 0.0055 Practices(1) (1) Including determinations where: 1) no control is specified and 2) the use of clean gaseous fuels.

Solvay proposes converting to natural gas and using good combustion practices as BACT control for VOC emissions from Sources #18 and #19. Natural gas combustion is inherently a low-VOC emitting process. The resulting BACT VOC emission rates for Sources #18 and #19 are 0.0054 lb/MMBtu each.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal. There is no NSPS VOC emission standard under 40 CFR 60, Subpart D.

2.2.4 GHG The results of the RBLC search for pollutant “carbon dioxide” are summarized in Table 2-8.

Table 2-8. GHG Control Options for Sources #18 and #19

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 32 105 to 137 Practices(1) (1) Including determinations where no control is specified.

Solvay proposes converting to natural gas and using good combustion practices as BACT control for GHG emissions from Sources #18 and #19. The resulting BACT GHG (CO2e) emission rates for Sources #18 and #19 are 117 lb/MMBtu each. A discussion of CCS is provided in Section 2.1.4.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal.

2.3 Soda Ash Product Crushing, Screening, and Transfers Source #110, that is, the “E” Train Dryer Areas, includes crushing, screening, and material transfers of the soda ash dried in Source #111, the DR-8 Product Dryer. These activities generate particulate emissions and are subject to 40 CFR 60, Subpart OOO. The BACT review for particulate emissions from these sources is provided in the following subsection.

Appendix H, Page 13

PM emission control technologies for Soda Ash Product Crushing, Screening, and Transfers were obtained from the RBLC. The RBLC was searched for all determinations in the last 10 years under the process name/description containing the keywords “crush,” “screen,” or “transfer.” The downloaded records were then further filtered as follows:

• PROCESS_NAME: Contains “transfer,” “screen,” or “crush”

• PROCESS_TYPE: 90 to 90.999, Mineral Products

• CASE-BY-CASE_BASIS: BACT-PSD

2.3.1 Particulates The results of the RBLC search for pollutant “particulate” are summarized in Table 2-9. For determinations that included more than one emission limit (i.e., separate emission limits for

PM, PM10, and PM2.5), only the unique PM limits are shown in Table 2-9 to avoid duplicate control determinations.

Table 2-9. PM Control Options for Sources #81 and #110

Number of Emission Limit Control Technology Determinations (gr/dscf) Baghouse(1) 33 0.00002 to 0.01

Wet Scrubber 1 0.005

Water Sprays 1 No Information

Enclosure 3 0.0005 to 0.002

No Control Specified 3 No Information (1) Including dust collectors and fabric filters.

In addition to the control options shown in Table 2-9, an ESP is another possible control option for Source #110. Control effectiveness rankings for the possible control technologies, from highest to lowest, are (1) baghouse, (2) ESP, (3) wet scrubber, and (4) water sprays.7 The control efficiency of enclosures depends on the enclosure’s capture efficiency.

Solvay proposes selecting the top control option of a baghouse for Source #110 to reduce

particulate emissions. The resulting particulate (PM, PM10, and PM2.5) emission rates are 0.006 gr/dscf for Source #110. This emission rate is below the applicable NSPS OOO emission standard of 0.014 gr/dscf per 40 CFR §60.672(a).

7 AP-42, Fifth Edition (EPA 1995) provides control efficiencies for these emission control technologies except for enclosures.

Appendix H, Page 14

The operating costs for baghouses include electricity for the baghouse fan and maintenance. Environmental impacts from a baghouse include the disposal of waste generated by the dust collector (i.e., worn-out or broken bags).

2.4 Product Dryer Source #111, that is, the DR-8 Product Dryer, will be added to the process. This dryer is not subject to an NSPS standard under 40 CFR 60. The BACT review for the emissions of CO, PM,

PM10, PM2.5, O3 (VOC), and GHG from the dryer is provided in the following subsections.

The emission control technologies for the Product Dryer were obtained from the RBLC. The RBLC was searched for all determinations in the last 10 years under the process name/description containing the keyword “dryer.” The downloaded records were then further filtered as follows:

• PROCESS_NAME: Contains “dryer”

• PROCESS_TYPE: 80 to 90.999, Metallurgical Industry, Nonferrous Metals Industry, and Mineral Products

• PRIMARY_FUEL: Contains “natural gas” or “nat gas”

• CASE-BY-CASE_BASIS: BACT-PSD

2.4.1 CO The results of the RBLC search for pollutant “carbon monoxide” are summarized in Table 2-10.

Table 2-10. CO Control Options for Source #111

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 11 0.03 to 0.84 Practices(1) (1) Including determinations where no control is specified.

An additional control option not found in the RBLC search is a catalytic oxidizer. However, there are no catalytic oxidizers installed on any of the product dryers (five facilities) in the southwest Wyoming trona patch. Therefore, it can be inferred that this control option is not considered technically feasible and/or cost-effective for product dryers. The estimated total capital investment for a catalytic oxidizer system for System #111 would be approximately $2 million.8

8 This cost is based on Section 3.2, Chapter 2, Equation 2.37 of the EPA Control Cost Manual (EPA 2017) for an exhaust flow rate of 42,800 scfm from Source #111. The 1988-dollar values from this figure were converted to 2019 dollars by multiplying by 2.14.

Appendix H, Page 15

Solvay proposes firing the product dryer with natural gas and using good combustion practices as BACT control for CO emissions from Source #111. The resulting BACT CO emission rate is 1.46 lb/MMBtu.

The capital costs, energy costs, and environmental impacts of using good combustion practices are minimal.

2.4.2 Particulates The results of the RBLC search for pollutant “particulate” are summarized in Table 2-11. For determinations that included more than one emission limit (i.e., separate emission limits for

PM, PM10, and PM2.5), only the unique PM limits are shown in Table 2-11 to avoid duplicate control determinations.

Table 2-11. PM Control Options for Source #111

Number of Emission Limit Control Technology Determinations (gr/dscf) Baghouse 4 0.006 to 0.02

Wet Scrubber 1 0.1

None Specified 6 No Information

An additional control option not found in the RBLC search is an ESP. Control effectiveness rankings for the possible control technologies, from highest to lowest, are (1) baghouse, (2) ESP, and (3) wet scrubber.9 However, there are no baghouses installed on any of the product dryers (five facilities) in the southwest Wyoming trona patch. These dryers are controlled by either a wet scrubber or an ESP. Note that the exhaust stream from product dryers is both wet (40 percent moisture) and alkaline, which can adversely affect baghouse performance. Therefore, it can be inferred that this control option is not considered technically feasible and/or cost- effective for product dryers.

Solvay proposes an ESP for Source #111 as BACT to reduce particulate emissions. The resulting

BACT particulate (PM, PM10, and PM2.5) emission rate is 0.01 gr/dscf.

The operating costs for an ESP include electricity and maintenance. Environmental impacts from an ESP are minimal as it does not generate waste.

2.4.3 VOC The results of the RBLC search for pollutant “volatile organic compounds” are summarized in Table 2-12.

9 AP-42, Fifth Edition (EPA 1995) provides control efficiencies for these emission control technologies.

Appendix H, Page 16

Table 2-12. VOC Control Options for Sources #82 and #111

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 10 0.0054 to 0.16 Practices(1) (1) Including determinations where: 1) no control is specified and 2) the use of clean gaseous fuels.

Solvay proposes firing the product dryer with natural gas and using good combustion practices as BACT control for VOC emissions from Source #111. Natural gas combustion is inherently a low-VOC emitting process. The resulting BACT VOC emission rate is 0.005 lb/MMBtu.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal.

2.4.4 GHG The results of the RBLC search for pollutant “carbon dioxide” are summarized in Table 2-13.

Table 2-13. GHG Control Options for Sources #82 and #111

Number of Emission Limit Control Technology Determinations (lb/MMBtu) Good Combustion 6 117 to 135 Practices(1) (1) Including determinations where: 1) no control is specified and 2) the use of clean gaseous fuels.

Solvay proposes firing the product dryer with natural gas and using good combustion practices

as BACT control for GHG emissions from Source #111. The resulting BACT GHG (CO2e) emission rate is 117 lb/MMBtu.

The capital costs, energy costs, and environmental impacts of using good combustion practices and natural gas are minimal.

Appendix H, Page 17

3.0 STATE-ONLY BACT

This section provides a State-Only BACT proposal for each emission unit and pollutant described in Section 1.1, Table 1-3. See Section 2.0 for the PSD BACT for all other emission units and pollutants. PSD BACT is presumed to meet State-Only BACT.

3.1 CO, Particulates, VOC, and GHG Table 3-1 provides the proposed BACT for CO, PM, VOC, and GHG emissions from Sources #81 and #82. Solvay is proposing to increase the permitted throughput limit from 160 to 200 tons per hour. This change to the permit limit does not require a physical change or a change in the method of operation of the emission unit equipment, nor does it require a change to any of the permitted emission limits. Therefore, it is not subject to PSD BACT, as discussed with the Wyoming Department of Environmental Quality (WDEQ) on February 28, 2019 (WDEQ and Solvay 2019).

Table 3-1. State-Only BACT for CO, Particulates, VOC, and GHG

Source ID Source Description Pollutant Proposed BACT Good combustion practices and the use of natural 81 "D" Train Dryer Area PM gas. No change to the currently permitted emission limit of 0.5 lb/hr Good combustion practices and the use of natural 82 DR-6 Product Dryer All gas. No change to the following currently permitted emission limits: CO 300 lb/hr

PM 3.45 lb/hr VOC and No permit limit currently specified GHG

3.2 SO2

Table 3-2 provides the proposed BACT for SO2 emissions from Sources #17, #18, #19, #82, and #111. As shown in Table 1-1, the proposed modification for these sources will result in a decrease in SO2 emissions.

Appendix H, Page 18

Table 3-2. Sources and Pollutants Requiring a State-Only BACT

Source ID Source Description Pollutant Proposed BACT

17 "A" and "B" Calciners SO2 Firing exclusively on natural gas – 0 lb/hr10

18 #1 Natural Gas-Fired Boiler SO2 Firing exclusively on natural gas – 0.6 lb/MMscf

19 #2 Natural Gas-Fired Boiler SO2 Firing exclusively on natural gas – 0.6 lb/MMscf

82 DR-6 Product Dryer SO2 Firing exclusively on natural gas – 0.6 lb/MMscf

111 DR-8 Product Dryer SO2 Firing exclusively on natural gas – 0.6 lb/MMscf

3.3 NOX

Table 3-3 provides the proposed BACT for NOX emissions from Sources #17, #18, #19, #82, and #111. As shown in Table 1-1, the proposed modification for these sources will result in a

decrease in NOX emissions.

Table 3-3. Sources and Pollutants Requiring a State-Only BACT

Source ID Source Description Pollutant Proposed BACT

Natural gas and ultra-low NOX burners – 17 "A" and "B" Calciners NOX 0.036 lb/MMBtu

Natural gas and low NOX burners – 0.024 18 #1 Natural Gas-Fired Boiler NOX lb/MMBtu

Natural gas and low NOX burners – 0.024 19 #2 Natural Gas-Fired Boiler NOX lb/MMBtu

Natural gas and low NOX burners – No 82 DR-6 Product Dryer NOX change to the currently permitted emission limit of 30 lb/hr

Natural gas and low NOX burners – 0.015 111 DR-8 Product Dryer NOX lb/MMBtu

10 Due to the adsorption properties of soda ash, SO2 emissions are expected to be zero.

Appendix H, Page 19

4.0 REFERENCES

EPA. 1995. "AP-42, Fifth Edition, Compilation of Air Pollutant Emission Factors, Volume I: Stationary Point and Area Sources." Office of Air Quality Planning and Standards. Appendix B.2, Table B.2-3, January.

—. 2017. "EPA Air Pollution Control Cost Manual, Sixth Edition." Chapter 2, Incinerators and Oxidizers, November. Accessed March 19, 2019. https://www.epa.gov/economic-and- cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air- pollution#cost%20manual.

—. 1990. "New Source Review Workshop Manual, Prevention of Significant Deterioration and Nonattainment Area Permitting, DRAFT." October.

—. 2019. "Technology Transfer Network, Clean Air Technology Center - RACT/BACT/LAER Clearinghouse." Accessed February 2019. http://www.epa.gov/ttn/catc/rblc/htm/rbxplain.html.

Vatavuk. 2003. "Escalation of EPA Air Pollution Control Cost Manual Incinerator Costs." Letter from W. Vatavuk, Vatavuk Engineering, to K. Lewis, Air Sciences, April 10.

WDEQ and Solvay. 2019. "Meeting at the Wyoming Department of Environmental Quality (WDEQ)." Meeting Time: 1:00 pm. Attendees: A. Keyfauver, N. Henschel, and A. Boltz of WDEQ; T. Brown of Solvay; K. Lewis and T. Martin of Air Sciences., February 28.

Appendix H, Page 20

Attachment H1 – Net Emissions Increase Calculations

Appendix H, Page H1-1

Table of Contents

Net Emissions Increase Calculations Net Emissions Increase Calculations ...... Attachment H1

Net Change in Emissions ...... H1-3 New/Modified Potential Emissions ...... H1-9

Appendix H, Page H1-2 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Net Change in Emissions

Past Actuals to Projected Actuals (or Potentials) Emissions (ton/yr) Description PM* NOX CO VOC SO2 CO2e Baseline Actual Emissions of Debottlenecked Sources (2016-2017) 203 1,275 4,940 1,212 48 1,314,384

Projected Actual Emissions of Debottlenecked Sources ** 147 252 5,884 537 1 1,060,384 Potential Emissions of New and Modified Sources 159 407 9,519 3,006 3 1,302,932 Contemporaneous Increases and Decreases 0.9 N/A N/A N/A N/A N/A Post-Modification Subtotal 306 660 15,403 3,543 4 2,363,316

Net Change in Emissions 103 -615 10,463 2,331 -44 1,048,932

PSD Significant Thresholds 10 40 100 40 40 75,000

PSD Triggered Yes No Yes Yes No Yes

* Assumes PM=PM10=PM2.5

** The projected actual emissions for the debottlenecked sources of NOx and SO2 are represented by potential emissions.

Potential Emissions of Lead Emissions (ton/yr) Description Lead Debottlenecked Sources 0.0023 Modified Sources 0.0030 New Sources 0.0004 Post-Modification Subtotal 0.0056

PSD Significant Thresholds 0.6

PSD Triggered No

Appendix H, Page H1-3 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Reported Actual Emissions 2-Year Average Emissions (ton/yr) Year PM NOX CO VOC SO2 PM NOX CO VOC SO2 2013 209.9 1,418.7 4,819.9 1,047.1 41.9 201 2014 215.6 1,376.5 4,981.3 1,065.9 28.4 212.8 1,397.6 4,900.6 1,056.5 35.1 201 2015 190.6 1,327.1 5,039.3 1,087.6 24.5 203.1 1,351.8 5,010.3 1,076.8 26.4 201 2016 188.1 1,298.3 4,887.5 1,115.3 63.6 189.3 1,312.7 4,963.4 1,101.5 44.0 201 2017 218.1 1,251.8 4,992.7 1,308.9 32.0 203.1 1,275.0 4,940.1 1,212.1 47.8 List of sources affected by the proposed modifications: Selected Baseline Actual Emissions (2016-2017) Src ID Description 2016-2017 203.1 1275.0 4940.1 1212.1 47.8 02A Ore Crusher Building #1 06A Product Silos - Top #1 06B Product Silos - Bottom #1 07 Product Loadout Station 10 Coal Crushing & Storage 11 Coal Transfer Station 14 Boiler Coal Bunker 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 16 Dryer Area 17 "A" and "B" Calciners 18 #1 Coal Fired Boiler 19 #2 Coal Fired Boiler 24 Boiler Fly Ash Silo 46 Ore Transfer Station 48 "C" Calciner 50 "C" Train Dryer Area 51 Product Dryer #5 52 Product Silo - Top #2 53 Product Silo - Bottom #2 67 Bottom Ash 76 "D" Train Primary Ore Screening 79 Ore Transfer Point 80 "D" Ore Calciner 81 "D" Train Dryer Area 82 DR-6 Product Dryer 99 Crusher Baghouse #2 100 Calciner Coal Bunker 103 East Ore Reclaim 104 West Ore Reclaim 109 Gas-fired Package Boiler

Reported Actual Production 2-Year Soda Ash Baseline Period Year MMTPY MMTPY 2013 2.55 2013-2014 2014 2.53 2.54 2014-2015 2015 2.61 2.57 2015-2016 2016 2.42 2.51 2016-2017 2017 2.61 2.52

Appendix H, Page H1-4 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Baseline Actual Emissions of Debottlenecked Sources Actual Activity Baseline Actual Emissions (ton/yr) Src ID Description hr/yr thru/yr units PM NOX CO VOC SO2 02A Ore Crusher Building #1 8,760 1,578,397 ton 7.01 0 0 0 0 06A Product Silos - Top #1 8,760 119,728 ton 1.31 0 0 0 0 06B Product Silos - Bottom #1 202 117,709 ton 0.05 0 0 0 0 07 Product Loadout Station 4,380 2,516,486 ton 2.63 0 0 0 0 10 Coal Crushing & Storage 3,333 264,627 ton 0.50 0 0 0 0 11 Coal Transfer Station 3,611 264,627 ton 0.36 0 0 0 0 14 Boiler Coal Bunker 2,446 181,646 ton 0.49 0 0 0 0 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 8,403 1,024,711 ton 2.65 0 000 16 Dryer Area 8,370 747,501 ton 3.77 0 0 0 0 17 "A" and "B" Calciners 7,073 1,174,636 ton 49.41 198.26 974.96 869.23 2.94 18 #1 Coal Fired Boiler 8,405 1,802,667 MMBtu 11.72 448.91 50.22 1.80 29.53 19 #2 Coal Fired Boiler 8,384 1,798,768 MMBtu 10.10 451.60 69.42 1.80 14.61 24 Boiler Fly Ash Silo 8,760 9,673 ton 1.31 0 0 0 0 46 Ore Transfer Station 8,760 1,578,397 ton 3.11 0 0 0 0 48 "C" Calciner 8,328 1,081,636 ton 27.94 23.67 1,085.91 178.47 0 50 "C" Train Dryer Area 8,518 710,914 ton 2.98 0 0 0 0 51 Product Dryer #5 8,518 710,914 ton 0.68 32.49 150.59 2.21 0 52 Product Silo - Top #2 8,580 2,559,072 ton 2.14 0 0 0 0 53 Product Silo - Bottom #2 4,179 2,516,486 ton 0.94 0 0 0 0 67 Bottom Ash 8,760 9,673 ton 2.06 0 0 0 0 76 "D" Train Primary Ore Screening 8,570 1,291,029 ton 10.50 0 0 0 0 79 Ore Transfer Point 8,570 1,291,029 ton 3.60 0 0 0 0 80 "D" Ore Calciner 8,444 1,803,339 ton 30.58 42.95 2,431.83 153.28 0 81 "D" Train Dryer Area 8,415 943,176 ton 2.10 0 0 0 0 82 DR-6 Product Dryer 8,415 943,176 ton 4.88 67.12 143.53 2.50 0 99 Crusher Baghouse #2 8,760 1,578,397 ton 14.02 0 0 0 0 100 Calciner Coal Bunker 2,427 82,981 ton 0.24 0 0 0 0 103 East Ore Reclaim 8,760 789,198 ton 1.45 0 0 0 0 104 West Ore Reclaim 8,760 789,198 ton 1.18 0 0 0 0 109 Gas-fired Package Boiler 7,155 873,480 MMBtu 3.36 10.02 33.63 2.79 0.72 Total 203 1,275 4,940 1,212 48 thru/yr = ton/yr or MMBtu/yr chk chk chk chk chk

Baseline Actual GHG Emissions of Existing Sources and Projected Actual GHG Emissions of Debottlenecked Sources 63% Increase Baseline Baseline Projected Actual Emissions Actual Activity Emission Factors CO2e Actual Activity CO2e

Src ID Description Material thru/yr units CO2 CH4 N2O units ton/yr thru/yr units ton/yr Debottlenecked Sources 48 "C" Calciner Throughput 1,081,636 ton 400 lb/ton 2.16E+05 1,752,000 ton 3.50E+05 51 Product Dryer #5 Fuel 602,343 MMBtu 53.06 0.001 0.0001 kg/MMBtu 3.53E+04 980,002 MMBtu 5.74E+04 80 "D" Ore Calciner Throughput 1,803,339 ton 400 lb/ton 3.61E+05 2,847,000 ton 5.69E+05 109 Gas-fired Package Boiler Fuel 873,480 MMBtu 53.06 0.001 0.0001 kg/MMBtu 5.11E+04 1,421,138 MMBtu 8.32E+04 Modified Sources 17 "A" and "B" CalcinersThroughput 1,174,636 ton 400 lb/ton 2.35E+05 See Potential Emission 18 #1 Coal Fired Boiler Fuel 1,802,667 MMBtu 93.28 0.011 0.0016 kg/MMBtu 1.87E+05 calculations on Page 4 19 #2 Coal Fired Boiler Fuel 1,798,768 MMBtu 93.28 0.011 0.0016 kg/MMBtu 1.86E+05 82 DR-6 Product Dryer Fuel 731,037 MMBtu 53.06 kg/MMBtu 4.28E+04 Total 1.31E+06 1.06E+06

Conversion GWP 40 CFR 98, Table A-1 Subpart A 2.20462 lb/kg CO2 1 2,000 lb/ton CH4 25 N2O 298

Appendix H, Page H1-5 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 4 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Projected Actual Emissions of Debottlenecked Sources Proposed Product Increase: 2.52 4.1 62.7% Basis for Permit Projected Actual Emissions (ton/yr)* Src ID Description Projected Actuals units Limit PM NOX CO VOC SO2 02A Ore Crusher Building #1 8,760 hr/yr 8,760 7.01 0 0 0 0 06A Product Silos - Top #1 8,760 hr/yr 8,760 1.31 0 0 0 0 06B Product Silos - Bottom #1 329 hr/yr 8,760 0.08 0 0 0 0 07 Product Loadout Station 7,126 hr/yr 8,760 4.28 0 0 0 0 10 Coal Crushing & Storage 0 hr/yr 8,760 00000 11 Coal Transfer Station 0 hr/yr 8,760 00000 14 Boiler Coal Bunker 0 hr/yr 8,760 00000 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) 1,489,200 thru/yr ton 1,489,200 3.85 0 0 0 0 16 Dryer Area 8,760 hr/yr 8,760 3.94 0 0 0 0 17 "A" and "B" Calciners 0 hr/yr 8,760 00000 18 #1 Coal Fired Boiler 0 hr/yr 8,760 00000 19 #2 Coal Fired Boiler 0 hr/yr 8,760 00000 24 Boiler Fly Ash Silo 0 hr/yr 8,760 00000 46 Ore Transfer Station 8,760 hr/yr 8,760 3.11 0 0 0 0 48 "C" Calciner 1,752,000 thru/yr ton 1,752,000 35.04 38.34 1,758.93 289.08 0 50 "C" Train Dryer Area 8,760 hr/yr 8,760 3.07 0 0 0 0 51 Product Dryer #5 1,156,646 thru/yr ton 1,357,800 1.11 52.87 245.00 1.23 0 52 Product Silo - Top #2 8,760 hr/yr 8,760 2.19 0 0 0 0 53 Product Silo - Bottom #2 6,798 hr/yr 8,760 1.53 0 0 0 0 67 Bottom Ash 0 hr/yr 8,760 00000 76 "D" Train Primary Ore Screening 8,760 hr/yr 8,760 10.73 0 0 0 0 79 Ore Transfer Point 8,760 hr/yr 8,760 3.68 0 0 0 0 80 "D" Ore Calciner 2,847,000 thru/yr ton 2,847,000 43.80 67.81 3,839.22 242.00 0 81 "D" Train Dryer Area 0 hr/yr 8,760 00000 82 DR-6 Product Dryer 0 hr/yr 8,760 00000 99 Crusher Baghouse #2 8,760 hr/yr 8,760 14.02 0 0 0 0 100 Calciner Coal Bunker 0 hr/yr 8,760 00000 103 East Ore Reclaim 8,760 hr/yr 8,760 1.45 0 0 0 0 104 West Ore Reclaim 8,760 hr/yr 8,760 1.18 0 0 0 0 109 Gas-fired Package Boiler 1,421,138 thru/yr MMBtu 2,225,040 5.47 12.26 41.17 4.54 0.65 Total 147 171 5,884 537 1 *Emissions are scaled up from the baseline actuals by the Proposed Product Increase: 63%, but not to exceed the current permit limits (PTE).

Potential Emissions of New and Modified Sources Potential Emissions (ton/yr) Src ID Description PM NOX CO VOC SO2 CO2e Decommissioned Sources 10 Coal Crushing & Storage 0 0 0 0 0 0 11 Coal Transfer Station 0 0 0 0 0 0 14 Boiler Coal Bunker 0 0 0 0 0 0 24 Boiler Fly Ash Silo 0 0 0 0 0 0 67 Bottom Ash 0 00000 100 Calciner Coal Bunker 0 0 0 0 0 0 Modified Sources 17 "A" and "B" Calciners 96.41 63.07 6,675.12 2,978.40 0.00 700,800 18 #1 Natural Gas-Fired Boiler 12.63 40.68 125.43 9.14 1.00 198,488 19 #2 Natural Gas-Fired Boiler 12.63 40.68 125.43 9.14 1.00 198,488 81 "D" Train Dryer Area Non-NSR Modification 2.19 82 DR-6 Product Dryer Non-NSR Modification 15.11 131.40 1,314.00 4.72 0.52 102,578 New Sources 110 "E" Train Dryer Area 3.58 111 DR-8 Product Dryer 16.07 131.40 1,278.96 4.72 0.52 102,578 Total 159 407 9,519 3,006 3 1,302,932

Appendix H, Page H1-6 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 5 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Potential Emissions of all Existing Sources Operation 8,760 hr/yr New or Potential Annual Emissions (lb/hr) Potential Annual Emissions (ton/yr)

Src ID Description Modified PM NOX CO VOC SO2 PM NOX CO VOC SO2 02A Ore Crusher Building #1 no 1.60 7.01 0 0 0 0 06A Product Silos - Top #1 no 0.30 1.31 0 0 0 0 06B Product Silos - Bottom #1 no 0.51 2.23 0 0 0 0 07 Product Loadout Station no 1.20 5.26 0 0 0 0 10 Coal Crushing & Storage YES 0.3 1.31 0 0 0 0 11 Coal Transfer Station YES 0.2 0.88 0 0 0 0 14 Boiler Coal Bunker YES 0.4 1.75 0 0 0 0 15 DR-1 & 2 Steam Tube Dryers (DR-1 only for 2017) no 3.00 1.80 00 0 13.14 7.88 0 0 0 16 Dryer Area no 0.90 3.94 0 0 0 0 17 "A" and "B" Calciners YES 30.0 131.40 0 0 0 0 18 #1 Coal Fired Boiler YES 5.00 245.00 17.50 7E-07 70.00 21.90 1,073.10 76.65 0.00 306.60 19 #2 Coal Fired Boiler YES 5.00 245.00 17.50 7E-07 70.00 21.90 1,073.10 76.65 0.00 306.60 24 Boiler Fly Ash Silo YES 0.30 1.31 0 0 0 0 46 Ore Transfer Station no 0.71 3.11 0 0 0 0 48 "C" Calciner no 8.00 15.00 762 340 0 35.04 65.70 3,337.56 1,489.20 0 50 "C" Train Dryer Area no 0.70 3.07 0 0 0 0 51 Product Dryer #5 no 2.40 18.00 225 0.28 0.09 10.51 78.84 985.50 1.23 0.39 52 Product Silo - Top #2 no 0.50 2.19 0 0 0 0 53 Product Silo - Bottom #2 no 0.45 1.97 0 0 0 0 67 Bottom Ash YES 0.47 2.06 0 0 0 0 76 "D" Train Primary Ore Screening no 2.45 10.73 0 0 0 0 79 Ore Transfer Point no 0.84 3.68 0 0 0 0 80 "D" Ore Calciner no 10.00 20.00 1,048 553 0 43.80 87.60 4,590.24 2,419.95 0 81 "D" Train Dryer Area YES 0.50 2.19 0 0 0 0 82 DR-6 Product Dryer YES 3.45 30.00 300 0.27 0.12 15.11 131.40 1,314.00 1.18 0.52 99 Crusher Baghouse #2 no 3.2 14.02 0 0 0 0 100 Calciner Coal Bunker YES 0.2 0.88 0 0 0 0 103 East Ore Reclaim no 0.33 1.45 0 0 0 0 104 West Ore Reclaim no 0.27 1.18 0 0 0 0 109 Gas-fired Package Boiler no 1.89 2.80 9.40 1.37 0.15 8.29 12.26 41.17 6.00 0.65 Excluding New/Modified Subtotal 39 58 2,044 894 0 172 252 8,954 3,916 1

Potential GHG Emissions of all Existing Sources Operation 8,760 hr/yr Potential Potential

Actual Activity Emission Factors CO2e Src ID Description Material thru/hr units CO2 CH4 N2O units ton/yr Debottlenecked Sources 48 "C" Calciner Trona 200 ton 400 lb/ton 3.50E+05 51 Product Dryer #5 N.G. 150 MMBtu 53.06 0.001 0.0001 kg/MMBtu 7.69E+04 80 "D" Ore Calciner Trona 325 ton 400 lb/ton 5.69E+05 109 Gas-fired Package Boiler N.G. 254 MMBtu 53.06 0.001 0.0001 kg/MMBtu 1.30E+05 Total 1.13E+06

Conversion GWP 40 CFR 98, Table A-1 Subpart A 2.205 lb/kg CO2 1 2000 lb/ton CH4 25 N2O 298

Appendix H, Page H1-7 PROJECT TITLE: BY: Air Sciences Inc. Solvay K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 6 6 Net Emis AIR EMISSION CALCULATIONS SUBJECT: DATE: Net Change in Emissions March 19, 2019

Potential Emissions of Lead Operation 8,760 hr/yr Hourly Annual Lead Src ID Description Fuel MMBtu/hr MMBtu/yr ton/yr Debottlenecked Sources 48 "C" Calciner N.G 250 2,190,000 0.0005 51 Product Dryer #5 N.G 150 1,314,000 0.0003 80 "D" Ore Calciner N.G 400 3,504,000 0.0009 109 Gas-fired Package Boiler N.G 254 2,225,040 0.0005 Modified Sources 17 "A" and "B" Calciners N.G 400 3,504,000 0.0009 18 #1 Natural Gas-Fired Boiler N.G 387 3,390,120 0.0008 19 #2 Natural Gas-Fired Boiler N.G 387 3,390,120 0.0008 82 DR-6 Product Dryer N.G 200 1,752,000 0.0004 New Sources 111 DR-8 Product Dryer N.G 200 1,752,000 0.0004 Total 0.0056

Lead Emission Factor 0.0005 lb/MMscf AP-42, Section 1.4, Table 1.4-2 (Rev. 7/98)

Conversion 2,000 lb/ton 1,020 Btu/scf AP-42 Table 1.4-2 (7/98), footnote a

Appendix H, Page H1-8 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 2 New-Mod AIR EMISSION CALCULATIONS SUBJECT: DATE: New/Modified Potential Emissions March 19, 2019

#18 - #1 Natural Gas-Fired Boiler #19 - #2 Natural Gas-Fired Boiler Operating Schedule 8,760 hr/yr, ea 2 units Exhaust Parameters 76,425 scfm, ea Detroit Stoker Co, 1/9/2019 letter 174,179 acfm, ea. 10% moisture 152,900 scfm, tot 400 F Detroit Stoker Co, 1/9/2019 letter Design Throughput 387 MMBtu/hr, N.G., ea, HHV Permit No. 3-1-126

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 7.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 5.8 25.3 0.0075 lb/MMBtu NOX 0.024 lb/MMBtu Detroit Stoker Co, 1/9/2019 letter 18.6 81.4 CO 0.074 lb/MMBtu Detroit Stoker Co, 1/9/2019 letter 57.3 250.9 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 4.2 18.3 0.0054 lb/MMBtu SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.5 2.0

CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 90,540 396,567

CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 1.71 7.47

N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.17 0.75

CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 90,634 396,976 117 lb/MMBtu

#17 - "A" and "B" Calciners Operating Schedule 8,760 hr/yr, ea 2 units Exhaust Parameters 85,603 scfm, ea Detroit Stoker Co, 8/13/2018 lett 70 F, std 140,300 acfm, ea. 85,280 scfm, each 68 F, std 230 F Detroit Stoker Co, 8/13/2018 letter 280,600 acfm, total Design Throughput 200 ton/hr, ea Proposed limit 170,600 scfm, total 200 MMBtu/hr, N.G., ea, HHV Detroit Stoker Co, 8/13/2018 letter

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.015 gr/scf Required vendor guarantee 22.0 96.4 NOX 0.036 lb/MMBtu Detroit Stoker Co, 8/13/2018 letter 14.4 63.1 CO 3.81 lb/ton T. Brown, Solvay, 8/3/2018 1,524 6,675.1 3.81 lb/MMBtu VOC 1.7 lb/ton Proposed rate 680 2,978.4

SO2 0 lb/MMscf Negligible - soda ash adsorption 0.0 0.0

CO2e 400 lb/ton AP-42 Table 8.12-4 (1/95) Monohydra1.6E+05 7.0E+05

Site Pressure Calculation http://www.sensorsone.com/altitude-pressure-units-conversion/ ft mmHg 0 29.921 6,000 23.978 7,000 23.088 6,239 23.765 0.794 atm

Conversions GWP 40 CFR 98, Table A-1 Subpart A 60 s/min and min/hr 0 C, std 273.15 C to K Metric CO2 1

7,000 gr/lb 68 F, std 459.67 F to R English CH4 25

2,000 lb/ton 2.20462 lb/kg N2O 298 1,020 Btu/scf AP-42 Table 1.4-2 (7/98), footnote a 3 3 35.315 ft /m

Appendix H, Page H1-9 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 2 New-Mod AIR EMISSION CALCULATIONS SUBJECT: DATE: New/Modified Potential Emissions March 19, 2019

#81 - "D" Train Dryer Area Non-NSR Modification Operating Schedule 8,760 hr/yr, ea Exhaust Parameters 10,000 acfm Permit No. 3-1-126 7,950 scfm

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.0073 gr/dscf Permit No. 3-1-126 0.5 2.2

#82 - DR-6 Product Dryer Non-NSR Modification Operating Schedule 8,760 hr/yr Exhaust Parameters 40,400 dscfm 129,100 acfm Dwg. 550-PF-142B v5, stream 521 Design Throughput 200 ton/hr Proposed limit 43.51% water by vol. Dwg. 550-PF-142B v5, stream 521 200 MMBtu/hr, N.G. 297.7 F Dwg. 550-PF-142B v5, stream 521

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.01 gr/dscf Permit No. 3-1-126 3.45 15.1

NOX 0.15 lb/MMBtu Permit No. 3-1-126 30 131.4 CO 1.5 lb/MMBtu Permit No. 3-1-126 300 1,314.0 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 1.1 4.7 0.0054 lb/MMBtu SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.1 0.5

CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 23,395 102,472

CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.44 1.93

N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.04 0.19 CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 23,420 102,578 117 lb/MMBtu

#110 - "E" Train Dryer Area Operating Schedule 8,760 hr/yr, ea Exhaust Parameters 20,000 acfm Proposed flow 15,890 scfm

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.006 gr/dscf Required vendor guarantee 0.8 3.6

#111 - DR-8 Product Dryer Operating Schedule 8,760 hr/yr 3 Exhaust Parameters 143,100 acfm 243,010 m /h FLSmidth, Dwg. 50090360 v.2.0, Stream G8 350.6 F 177 C FLSmidth, Dwg. 50090360 v.2.0, Stream G8 42.11% 42.11% water by vol. FLSmidth, Dwg. 50090360 v.2.0, Stream G8 3 42,800 dscfm 117,210 Nm /h (wet) FLSmidth, Dwg. 50090360 v.2.0, Stream G8 Design Throughput 200 ton/hr Proposed limit 200 MMBtu/hr, N.G., HHV FLSmidth, Dwg. 50090360 v.2.0, Stream S90, converted to HHV

Potential Emissions Emissions Pollutant BACT Limit Reference lb/hr ton/yr PM 0.01 gr/dscf Required vendor guarantee 3.67 16.1 NOX 0.15 lb/MMBtu FLSmidth, Dwg. 50090360 v.2.0 30.0 131.4 CO 1.46 lb/MMBtu FLSmidth 11/5/2018 email 292.0 1,279 VOC 5.5 lb/MMscf AP-42 Table 1.4-2 (7/98) 1.1 4.7 0.0054 lb/MMBtu

SO2 0.6 lb/MMscf AP-42 Table 1.4-2 (7/98) 0.1 0.5

CO2 53.06 kg/MMBtu 40 CFR 98, Table C-1 Subpart C 23,395 102,472

CH4 0.001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.44 1.93

N2O 0.0001 kg/MMBtu 40 CFR 98, Table C-2 Subpart C 0.04 0.19 CO2e 53.1148 kg/MMBtu 40 CFR 98, Table A-1 Subpart A 23,420 102,578 117 lb/MMBtu

Appendix H, Page H1-10

Attachment H2 – RBLC Search Downloads

Appendix H, Page H2-1

Table of Contents

RBLC Search Downloads RBLC Search Downloads ...... Attachment H2

BACT Determinations for: Calciners – CO ...... H2-3 Calciners – Particulates ...... H2-4 Calciners – VOC ...... H2-5 Calciners – GHG ...... H2-6 Natural Gas-Fired Boilers – CO ...... H2-7 Natural Gas-Fired Boilers – Particulates ...... H2-8 Natural Gas-Fired Boilers – VOC ...... H2-9 Natural Gas-Fired Boilers – GHG ...... H2-10 Soda Ash Product Crushing, Screening and Transfers – Particulates ...... H2-12 Product Dryer – CO ...... H2-14 Product Dryer – Particulates ...... H2-15 Product Dryer – VOC ...... H2-16 Product Dryer – GHG ...... H2-17

Appendix H, Page H2-2 Stadardized BACT Determinations for Calciners - Carbon Monoxide Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/ton AL-0313 05/04/2016  ACT VERTICAL LIME KILN 90.019 NATURAL GAS 100 MMBTU/H Carbon Monoxide PARALLEL FLOW REGENERATIVE VERTICAL 36 LB/H 1.30000 KILN DESIGN GOOD COMBUSTION AND PROCESS CONTROL TECHNOLOGIES FL-0341 02/20/2014  ACT Two vertical lime kilns 90.019 Natural gas 330 tons of lime per day Carbon Monoxide -Efficient, vertical twin shaft PFR kiln design to 400 MG / N CU minimize fuel use and resulting emissions of all METER pollutants; -Thorough mixing and residence time through preheat section to complete burnout of CO and volatile organic compounds (VOC); -Lime production GA-0147 01/27/2012  ACT CALCINERS/KILNS 90.017 NATURAL GAS 4.9 MMBTU/H Carbon Monoxide GOOD COMBUSTION PRACTICES 33 LB/H EA OK-0159 11/04/2013  ACT EUG 4 KILN DEPT / VERTICAL 90.019 NATURAL GAS 240 TPY Carbon Monoxide A properly designed and operated kiln effectively 4.22 LB/ TON OF 4.22000 LIME KILN functions as a thermal oxidizer. Carbon monoxide LIME formation is minimized when the kiln temperature and excess oxygen availability is adequate for complete combustion. SC-0113 02/08/2012  ACT CALCINING/SINTERING KILN 90.008 NATURAL GAS 56.8 MMBTU/H Carbon Monoxide GOOD DESIGN AND COMBUSTION 33.55 LB/H PRACTICES. THE GOOD COMBUSTION PRACTICES WILL BE DEVELOPED AND MAINTAINED IN AN OPERATIONS AND MAINTENANCE MANUAL (O & M MANUAL) WHICH SPECIFIES PROPER OPERATION AND REPAIR OF THE KILNS.

TX-0726 02/22/2010  ACT Rotary Kiln 2 90.019 natural gas, coal, and 504 tons per day Carbon Monoxide Proper kiln design and operation (good engineering 3 LB/TON FEED 3.00000 petroleum coke practice/best management practice) to minimize the products of incomplete combustion.

TX-0726 02/22/2010  ACT Rotary Kiln 3 90.019 natural gas, coal, and 850 tons per day Carbon Monoxide Proper kiln design and operation (good engineering 2.2 LB/TON FEED 2.20000 petroleum coke practice/best management practice) to minimize the products of incomplete combustion.

7 No. of Determinations Minimum 1.3 Maximum 4.22

Attachment H, H2-3 Stadardized BACT Determinations for Calciners - Particulates Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT gr/dscf AL-0313 05/04/2016  ACT VERTICAL LIME KILN 90.019 NATURAL GAS 100 MMBTU/H Particulate matter, filterable FABRIC FILTER BAGHOUSE 0.009 GR/DSCF 0.00900 (FPM) FL-0341 02/20/2014  ACT Two vertical lime kilns 90.019 Natural gas 330 tons of lime per day Particulate matter, total (TPM) -Baghouse for each kiln; 10 MG / N CU ND -Efficient, vertical twin shaft PFR kiln design to METER minimize fuel use and resulting emissions of all pollutants; GA-0147 01/27/2012  ACT CALCINERS/KILNS 90.017 NATURAL GAS 4.9 MMBTU/H Particulate matter, total (TPM) ‘‘CATALYTIC 0.01 GR/DSCF 0.01000 BAGHOUSE‘‘/CERAMIC FILTER TUBE SYSTEM MN-0084 12/06/2011  ACT GRATE KILN - DOWN DRAFT 90.031 BIOMASS & 450 T/PELLETS/H Particulate Matter (PM) DRY ELECTROSTATIC PRECIPITATOR 10.5 LB/H 0.00600 DRYING ZONE 1 NATURAL GAS MN-0084 12/06/2011  ACT GRATE KILN - DOWN DRAFT 90.031 BIOMASS & 450 T/PELLETS/H Particulate matter, filterable < DRY ELECTROSTATIC PRECIPITATORS 21 LB/H 0.01200 DRYING ZONE 1 NATURAL GAS 10 µ (FPM10) SC-0113 02/08/2012  ACT CALCINING/SINTERING KILN 90.008 NATURAL GAS 56.8 MMBTU/H Particulate matter, filterable < CATALYTIC BAGHOUSE 0.01 GR/DSCF 0.01000 10 µ (FPM10) SC-0113 02/08/2012  ACT CALCINING/SINTERING KILN 90.008 NATURAL GAS 56.8 MMBTU/H Particulate Matter (PM) CATALYTIC BAGHOUSE 0.01 GR/DSCF 0.01000

TX-0726 02/22/2010  ACT Rotary Kiln 2 90.019 natural gas, coal, and 504 tons per day Particulate matter, total < 10 The use of fabric filter to achieve a 0.01 gr/dscf 0ND petroleum coke µ (TPM10) filterable and condensable PM10. TX-0726 02/22/2010  ACT Rotary Kiln 3 90.019 natural gas, coal, and 850 tons per day Particulate matter, total < 10 The use of fabric filter to achieve a 0.01 gr/dscf 0ND petroleum coke µ (TPM10) filterable and condensable PM10.

9 No. of Determinations Minimum 0.006 Maximum 0.012

Attachment H, H2-4 Stadardized BACT Determinations for Calciners - Volatile Organic Compounds Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0313 05/04/2016  ACT VERTICAL LIME KILN 90.019 NATURAL GAS 100 MMBTU/H Methane PARALLEL FLOW REGENERATIVE VERTICAL 4 MMBTU ND KILN HHV/TON ENERGY EFFICIENT OPERATING PRACTICES LIME GA-0147 01/27/2012  ACT CALCINERS/KILNS 90.017 NATURAL GAS 4.9 MMBTU/H Volatile Organic Compounds USE OF ONLY NATURAL GAS AND PROPANE 0.54 LB/H EA 0.11020 (VOC) AS FUEL IN-0290 08/13/2018  ACT board, kiln, dryer 90.019 NATURAL GAS 433000 T/YR Volatile Organic Compounds 0.1 LB/T ND (VOC) PA-0283 11/19/2012  ACT KILN NO. 8 90.019 Pipeline quality natural 0 Methane 3.65 MMBTU/TON ND gas LIME (HHV) SC-0113 02/08/2012  ACT CALCINING/SINTERING KILN 90.008 NATURAL GAS 56.8 MMBTU/H Volatile Organic Compounds GOOD DESIGN AND COMBUSTION 0.62 LB/H 0.01092 (VOC) PRACTICES. THE GOOD COMBUSTION PRACTICES WILL BE DEVELOPED AND MAINTAINED IN AN OPERATIONS AND MAINTENANCE MANUAL (O & M MANUAL) WHICH SPECIFIES PROPER OPERATION AND REPAIR OF THE KILNS.

5 No. of Determinations Minimum 0.01 Maximum 0.1

Attachment H, H2-5 Stadardized BACT Determinations for Calciners - Carbon Dioxide Equivalent (CO2e) Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/ton AL-0313 05/04/2016  ACT VERTICAL LIME KILN 90.019 NATURAL GAS 100 MMBTU/H Carbon Dioxide Equivalent PARALLEL FLOW REGENERATIVE KILN 4 MMBTU ND (CO2e) DESIGN HHV/TON ENERGY EFFICIENT OPERATING PRACTICES LIME FL-0342 07/18/2014  ACT Two vertical lime kilns 90.019 Natural gas 396 tons lime per day per kiln Carbon Dioxide Equivalent Use of efficient kiln reduced fuel usage. Natural gas 0.99 TON 0.99000 (CO2e) minimized CO2 emissions. CO2E/TON LIME GA-0147 01/27/2012  ACT CALCINERS/KILNS 90.017 NATURAL GAS 4.9 MMBTU/H Carbon Dioxide Equivalent Good Heat Insulation, Heat Recovery, Good 436 LB/T 436.00000 (CO2e) Combustion Practices MN-0084 12/06/2011  ACT GRATE KILN - DOWN DRAFT 90.031 BIOMASS & 450 T/PELLETS/H Carbon Dioxide FUEL EFFICIENTY VIA HEAT RECOVERY FROM 114000 T ND * DRYING ZONE 1 NATURAL GAS PELLET COOLERS. ALSO, USE OF A PRIMARY FUEL/CO2/YR FUEL MIX OF 50% BIOMASS/50% NATURAL GAS. SC-0113 02/08/2012  ACT CALCINING/SINTERING KILN 90.008 NATURAL GAS 56.8 MMBTU/H Carbon Dioxide CONTROL METHOD FOR CO2E: ENERGY 0ND EFFICIENT DESIGN AND OPERATION, WASTE HEAT RECOVERY DESIGN, NATURAL GAS/PROPANE.

5 No. of Determinations Minimum 1 Maximum 436

Attachment H, H2-6 Stadardized BACT Determinations for Boilers - Carbon Monoxide Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu *FL-0330 12/01/2011  ACT Boilers (4 - 278 mmbtu/hr each) 11.31 natural gas 0 Carbon Monoxide Good Combustion Practices 0.015 LB/MMBTU 0.01500 FL-0344 08/27/2013  ACT Natural Gas Boiler 11.31 Natural gas 589 MMBTU/H Carbon Monoxide Overfire air and proper combustion 0.08 LB/MMBTU 0.08000 IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Carbon Monoxide good combustion practices 0.0013 LB/MMBTU 0.00130 IA-0106 07/12/2013  ACT Boilers 11.31 natural gas 456 MMBTU/H Carbon Monoxide oxidation catalyst 0.0013 LB/MMBTU 0.00130 IA-0108 11/07/2013  ACT Boiler 11.31 natural gas 213.6 MMBTU/H Carbon Monoxide 0.075 LB/MMBTU 0.07500 IA-0109 07/28/2015  ACT Boiler 7 11.31 natural gas 476 mmBtu/hr Carbon Monoxide Good combustion practices 0.2 LB/MMBTU 0.20000 IA-0109 07/28/2015  ACT Boiler 8 11.31 natural gas 775 mmBtu/hr Carbon Monoxide good combustion practices 0.2 LB/MMBTU 0.20000 ID-0021 04/21/2014  ACT PACKAGE BOILER 11.31 Natural Gas 275 MMBtu/hr (HHV) Carbon Monoxide 0.015 LB/MMBTU 0.01500 IL-0114 09/05/2014  ACT Boiler 11.31 natural gas 864 MMBTU/H Carbon Monoxide good combustion practices 0.02 LB/MMBTU 0.02000 IN-0166 06/27/2012  ACT TWO (2) AUXILIARY BOILERS 11.31 NATURAL GAS 408 MMBTU/H, EACH Carbon Monoxide GOOD COMBUSTION PRACTICES 0.036 LB/MMBTU 0.03600 IN-0234 12/08/2015  ACT BOILER 1 11.31 NATURAL GAS 271 MMBTU/H Carbon Monoxide GOOD COMBUSTION PRACTICES 0.0365 LB/MMBTU 0.03650 IN-0234 12/08/2015  ACT BOILER 2 11.31 NATURAL GAS 271 MMBTU/H Carbon Monoxide GOOD COMBUSTION 0.0365 LB/MMBTU 0.03650 LA-0231 06/22/2009  ACT AUXILIARY BOILER 11.31 NATURAL GAS 938.3 MMBTU/H Carbon Monoxide GOOD DESIGN AND PROPER OPERATION 33.78 LB/H 0.03600 LA-0233 01/30/2009  ACT 3(K-6)8 POWERHOUSE BOILER B- 11.31 NATURAL GAS 337.6 MMBTU/H Carbon Monoxide GOOD COMBUSTION CONTROL. VENDOR 41.04 LB/H 0.12156 5A GUARANTEE OF 70 PPM OR LESS LA-0233 01/30/2009  ACT 3(K-6)9 POWERHOUSE BOILER B- 11.31 NATURAL GAS 337.6 MMBTU/H Carbon Monoxide GOOD COMBUSTION CONTROL. VENDOR 41.04 LB/H 0.12156 5 GUARANTEE OF 70 PPM OR LESS LA-0248 01/27/2011  ACT DRI-109 - DRI Unit #1 Package 11.31 Natural Gas 1760 Billion Btu/yr Carbon Monoxide Good Combustion Practices 11.42 LB/H 0.00649 Boiler Flue Stack LA-0248 01/27/2011  ACT DRI-209 - DRI Unit #2 Package 11.31 Natural Gas 1760 Billion Btu/yr Carbon Monoxide Good Combustion Practices 11.42 LB/H 0.00649 Boiler Flue Stack LA-0254 08/16/2011  ACT AUXILIARY BOILER (AUX-1) 11.31 NATURAL GAS 338 MMBTU/H Carbon Monoxide USE OF PIPELINE QUALITY NATURAL GAS 84 LB/MMSCF 0.08235 AND GOOD COMBUSTION PRACTICES LA-0305 06/30/2016  ACT Auxiliary Boilers and 11.31 Natural Gas 0 Carbon Monoxide good engineering design and good combustion 0ND Superheaters practices LA-0311 07/15/2013  ACT No. 6 Ammonia Plant Boiler (15- 11.31 Natural Gas 612.4 MM Btu/hr Carbon Monoxide Good combustion practices; proper equipment 24.5 LB/HR 0.04001 13) and No. 5 Urea Boiler (23-13) design; use of natural gas as fuel. (EQTs 165 & 175) *LA-0312 06/30/2017  ACT B1-13 - Boiler 1 (EQT0003) 11.31 Natural Gas 350 MM BTU/hr Carbon Monoxide Good Combustion Practices 13.3 LB/HR 0.03800 *LA-0312 06/30/2017  ACT B2-13 - Boiler 2 (EQT0004) 11.31 Natural Gas 350 MM BTU/hr Carbon Monoxide Good Combustion Practices 13.3 LB/HR 0.03800 *LA-0312 06/30/2017  ACT B2-13-SUSD - Boiler 2 11.31 Natural Gas 515 MMBTU/hr Carbon Monoxide Follow manufacturer’s procedures for start-up 0ND Startup/Shutdown (EQT0006) and shutdown *LA-0312 06/30/2017  ACT B1-13-SUSD - Boiler 1 11.31 Natural Gas 515 MMBTU/hr Carbon Monoxide Follow manufacturer’s procedures for start-up 0ND Startup/Shutdown (EQT0005) and shutdown *LA-0315 05/23/2014  ACT Utility Boiler 1 11.31 Natural Gas 656 MMBTU/HR Carbon Monoxide Combustion controls (proper burner design and 22.97 LB/H 0.03502 operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 2 11.31 Natural Gas 656 MMBTU/HR Carbon Monoxide Combustion controls (proper burner design and 22.97 LB/H 0.03502 operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 3 11.31 Natural Gas 656 MMBTU/HR Carbon Monoxide Combustion controls (proper burner design and 22.97 LB/H 0.03502 operation using natural gas) LA-0323 01/09/2017  ACT No. 9 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Carbon Monoxide Good combustion practices and Boiler MACT 0.045 LB/MMBTU 0.04500 LA-0323 01/09/2017  ACT No. 10 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Carbon Monoxide Good combustion practices and Boiler MACT 0.045 LB/MMBTU 0.04500 ND-0032 06/20/2014  ACT Package boiler 11.31 Natural gas 280 MMBTU/H Carbon Monoxide good combustion practices 0.06 LB/MMBTU 0.06000 *ND-0033 08/10/2015  ACT Boilers 11.31 Natural gas 187.5 MMBTU/H Carbon Monoxide Good Combustion Practices 0.036 LB/MM BTU 0.03600 NE-0054 09/12/2013  ACT Boiler K 11.31 natural gas 300 mmbtu/h Carbon Monoxide GOOD COMBUSTION PRACTICES 0.08 LB/MMBTU 0.08000 OK-0150 01/17/2013  ACT BOILER 11.31 NATURAL GAS 3290 MMBTUH Carbon Monoxide 0.15 LB/MMBTU 0.15000 OK-0161 03/31/2014  ACT Boiler #3 11.31 Natural Gas 3290 MMBTUH Carbon Monoxide 0.465 LB/MMBTU 0.46500 OK-0162 05/29/2014  ACT Boiler 11.31 Natural Gas 450 MMBTUH Carbon Monoxide Natural Gas Fuel, Good Combustion Practices 0.037 LB/MMBTU 0.03700 OK-0168 05/05/2015  ACT NATURAL GAS-FIRED BOILER 11.31 NATURAL GAS 16456 MMBTUH Carbon Monoxide NO CONTROLS FEASIBLE;GOOD COMBUSTION 0.465 LB/MMBTU 0.46500 (>250MMBTUH) PRACTICES TX-0656 05/16/2014  ACT Boiler 11.31 natural gas and fuel gas 950 MMBTU/H Carbon Monoxide clean fuel and good combustion practices 96.4 T/YR ND

TX-0698 09/05/2013  ACT (3) gas-fired boilers 11.31 natural gas 550 MMBTU/H Carbon Monoxide good combustion practices 50 PPMVD 0.03695 TX-0704 12/02/2014  ACT (2) boilers 11.31 natural gas 450 MMBTU/H Carbon Monoxide good combustion practices 50 PPMVD 0.03695 TX-0704 12/02/2014  ACT boiler 11.31 natural gas 250 MMBTU/H Carbon Monoxide good combustion practices 50 PPMVD 0.03695 TX-0707 12/20/2013  ACT (2) boilers 11.31 natural gas 515 MMBTU/H Carbon Monoxide good combustion practices 50 PPMVD 0.03695 VA-0320 12/06/2012  ACT NATURAL GAS FIRED BOILERS, 11.31 Natural Gas 400 MMBTU/H Carbon Monoxide Good combustion practices 50 PPMVD @3% O2 0.03695 (6) WY-0074 11/18/2013  ACT Natural Gas Package Boiler 11.31 Natural Gas 254 MMBTU/H Carbon Monoxide good combustion practices 0.037 LB/MMBTU 0.03700

43 No. of Determinations Minimum 0.0013 Maximum 0.47

Attachment H, H2-7 Stadardized BACT Determinations for Boilers - Particulates Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu *FL-0330 12/01/2011  ACT Boilers (4 - 278 mmbtu/hr each) 11.31 natural gas 0 Particulate matter, filterable use of natural gas 0.01 LB/MMBTU 0.01000 (FPM) *FL-0330 12/01/2011  ACT Boilers (4 - 278 mmbtu/hr each) 11.31 natural gas 0 Particulate matter, total < 10 use of natural gas 0.0075 LB/MMBTU 0.00750 µ (TPM10) FL-0344 08/27/2013  ACT Natural Gas Boiler 11.31 Natural gas 589 MMBTU/H Particulate matter, total (TPM) Fuel monitoring for sulfur content 2 GRAINS S/100 ND SCF GAS IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Particulate matter, total (TPM) good combustion practices 0.0024 LB/MMBTU 0.00240 IA-0106 07/12/2013  ACT Boilers 11.31 natural gas 456 MMBTU/H Particulate matter, total (TPM) good operating practices and use of natural gas 0.0024 LB/MMBTU 0.00240

ID-0021 04/21/2014  ACT PACKAGE BOILER 11.31 Natural Gas 275 MMBtu/hr (HHV) Particulate matter, total < 10 0.0075 LB. 0.00750 µ (TPM10) IL-0114 09/05/2014  ACT Boiler 11.31 natural gas 864 MMBTU/H Particulate matter, filterable good combustion practices 0.0019 LB/MMBTU 0.00190 (FPM) IL-0114 09/05/2014  ACT Boiler 11.31 natural gas 864 MMBTU/H Particulate matter, total < 10 good combustion practices 0.0024 LB/MMBTU 0.00240 µ (TPM10) IL-0114 09/05/2014  ACT Boiler 11.31 natural gas 864 MMBTU/H Particulate matter, total < 2.5 good combustion practices 0.001 LB/MMBTU 0.00100 µ (TPM2.5) IN-0166 06/27/2012  ACT TWO (2) AUXILIARY BOILERS 11.31 NATURAL GAS 408 MMBTU/H, EACH Particulate matter, filterable USE OF CLEAN BURNING GASEOUS FUEL 0.0075 LB/MMBTU 0.00750 (FPM) IN-0234 12/08/2015  ACT BOILER 1 11.31 NATURAL GAS 271 MMBTU/H Particulate matter, filterable GOOD COMBUSTION PRACTICES 0.002 LB/MMBTU 0.00200 (FPM) IN-0234 12/08/2015  ACT BOILER 2 11.31 NATURAL GAS 271 MMBTU/H Particulate matter, filterable GOOD COMBUSTION PRACTICES 0.002 LB/MMBTU 0.00200 (FPM) IN-0234 12/08/2015  ACT BOILER 2 11.31 NATURAL GAS 271 MMBTU/H Particulate matter, total < 10 GOOD COMBUSTION PRACTICES 0.005 LB/MMBTU 0.00500 µ (TPM10) LA-0231 06/22/2009  ACT AUXILIARY BOILER 11.31 NATURAL GAS 938.3 MMBTU/H Particulate matter, total < 10 GOOD DESIGN AND PROPER OPERATION 6.99 LB/H 0.00745 µ (TPM10) LA-0248 01/27/2011  ACT DRI-109 - DRI Unit #1 Package 11.31 Natural Gas 1760 Billion Btu/yr Particulate matter, filterable < good combustion practices 2.38 LB/H ND Boiler Flue Stack 10 µ (FPM10) LA-0248 01/27/2011  ACT DRI-209 - DRI Unit #2 Package 11.31 Natural Gas 1760 Billion Btu/yr Particulate matter, filterable < good combustion practices 2.38 LB/H ND Boiler Flue Stack 10 µ (FPM10) LA-0254 08/16/2011  ACT AUXILIARY BOILER (AUX-1) 11.31 NATURAL GAS 338 MMBTU/H Particulate matter, total < 10 USE OF PIPELINE QUALITY NATURAL GAS 7.6 LB/MMSCF 0.00745 µ (TPM10) AND GOOD COMBUSTION PRACTICES

*LA-0273 05/23/2014  ACT Utility Steam Boiler No. 1, 2, and 11.31 Natural gas 0 Particulate matter, filterable < Gaseous fuels and good combustion practices 0.0075 LB/MM BTU 0.00750 3 (EQT0967, EQT0968, and 10 µ (FPM10) EQT0969) LA-0305 06/30/2016  ACT Auxiliary Boilers and 11.31 Natural Gas 0 Particulate matter, total < 10 good engineering design and proper operation 0 ND Superheaters µ (TPM10) *LA-0312 06/30/2017  ACT B1-13 - Boiler 1 (EQT0003) 11.31 Natural Gas 350 MM BTU/hr Particulate matter, total < 10 Good Combustion Practices & Use Pipeline 1.75 LB/HR 0.00500 µ (TPM10) Quality Natural Gas *LA-0312 06/30/2017  ACT B2-13 - Boiler 2 (EQT0004) 11.31 Natural Gas 350 MM BTU/hr Particulate matter, total < 10 Good Combustion Practices & Use Pipeline 1.75 LB/HR 0.00500 µ (TPM10) Quality Natural Gas *LA-0312 06/30/2017  ACT B2-13-SUSD - Boiler 2 11.31 Natural Gas 515 MMBTU/hr Particulate matter, total < 10 Follow manufacturer’s procedures for start- 0ND Startup/Shutdown (EQT0006) µ (TPM10) up and shutdown *LA-0312 06/30/2017  ACT B1-13-SUSD - Boiler 1 11.31 Natural Gas 515 MMBTU/hr Particulate matter, total < 10 Follow manufacturer’s procedures for start- 0ND Startup/Shutdown (EQT0005) µ (TPM10) up and shutdown *LA-0315 05/23/2014  ACT Utility Boiler 1 11.31 Natural Gas 656 MMBTU/HR Particulate matter, total < 10 Combustion Controls (proper burner design 4.89 LB/H 0.00745 µ (TPM10) and operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 2 11.31 Natural Gas 656 MMBTU/HR Particulate matter, total < 10 Combustion controls (proper burner design 4.89 LB/H 0.00745 µ (TPM10) and operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 3 11.31 Natural Gas 656 MMBTU/HR Particulate matter, total < 10 Combustion controls (proper burner design 4.89 LB/H 0.00745 µ (TPM10) and operation using natural gas) LA-0323 01/09/2017  ACT No. 9 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Particulate matter, total < 10 Good combustion practices and Boiler MACT 0.0075 LB/MMBTU 0.00750 µ (TPM10) LA-0323 01/09/2017  ACT No. 10 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Particulate matter, total < 10 Good combustion practices and Boiler MACT 0.0075 LB/MMBTU 0.00750 µ (TPM10) MN-0078 10/28/2009  ACT BOILER 11.31 NATURAL GAS 350 MMBTU/H Particulate matter, total < 2.5 2.5 LB/H 0.00714 µ (TPM2.5) ND-0032 06/20/2014  ACT Package boiler 11.31 Natural gas 280 MMBTU/H Particulate matter, filterable Good combustion practices 0.0067 LB/MMBTU 0.00670 (FPM) *ND-0033 08/10/2015  ACT Boilers 11.31 Natural gas 187.5 MMBTU/H Particulate matter, total (TPM) Good combustion practices 0.0067 LB/MM BTU 0.00670 NE-0054 09/12/2013  ACT Boiler K 11.31 natural gas 300 mmbtu/h Particulate matter, total < 2.5 GOOD COMBUSTION PRACTICES 0.0075 LB/MMBTU 0.00750 µ (TPM2.5) OK-0162 05/29/2014  ACT Boiler 11.31 Natural Gas 450 MMBTUH Particulate matter, total < 10 Natural Gas Fuel 0.0076 LB/MMBTU 0.00760 µ (TPM10) TX-0656 05/16/2014  ACT Boiler 11.31 natural gas and fuel gas 950 MMBTU/H Particulate matter, total < 10 clean fuel and good combustion practices 22.77 T/YR 0.00547 µ (TPM10) TX-0656 05/16/2014  ACT Boiler 11.31 natural gas and fuel gas 950 MMBTU/H Particulate matter, total < 2.5 clean fuel and good combustion practices 17.08 T/YR 0.00410 µ (TPM2.5) TX-0698 09/05/2013  ACT (3) gas-fired boilers 11.31 natural gas 550 MMBTU/H Particulate matter, total < 2.5 good combustion practices 0 ND µ (TPM2.5) TX-0704 12/02/2014  ACT (2) boilers 11.31 natural gas 450 MMBTU/H Particulate matter, total < 2.5 0ND µ (TPM2.5) TX-0704 12/02/2014  ACT boiler 11.31 natural gas 250 MMBTU/H Particulate matter, total < 2.5 0ND µ (TPM2.5) TX-0707 12/20/2013  ACT (2) boilers 11.31 natural gas 515 MMBTU/H Particulate matter, total < 2.5 good combustion practices, use of gaseous 0ND µ (TPM2.5) fuels WY-0074 11/18/2013  ACT Natural Gas Package Boiler 11.31 Natural Gas 254 MMBTU/H Particulate matter, total (TPM) good combustion practices 0.007 LB/MMBTU 0.00700

40 No. of Determinations Minimum 0.001 Maximum 0.01

Attachment H, H2-8 Stadardized BACT Determinations for Boilers - Volatile Organic Compounds Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0271 06/11/2014  ACT No.4 Power Boiler 11.31 Natural Gas 425 MMBTU/H Volatile Organic Compounds 0.0053 LB/MMBTU 0.00530 (VOC) *FL-0330 12/01/2011  ACT Boilers (4 - 278 mmbtu/hr each) 11.31 natural gas 0 Volatile Organic Compounds Good Combustion Practices 0.0054 LB/MMBTU 0.00540 (VOC) IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Volatile Organic Compounds good combustion practices 0.0014 LB/MMBTU 0.00140 (VOC) IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Methane good combustion practices 0.0023 LB/MMBTU 0.00230 IA-0106 07/12/2013  ACT Boilers 11.31 natural gas 456 MMBTU/H Volatile Organic Compounds good operating practices and use of natural gas 0.0014 LB/MMBTU 0.00140 (VOC) IA-0106 07/12/2013  ACT Boilers 11.31 natural gas 456 MMBTU/H Methane proper operation and use of natural gas 0.0023 LB/MMBTU 0.00230 ID-0021 04/21/2014  ACT PACKAGE BOILER 11.31 Natural Gas 275 MMBtu/hr (HHV) Volatile Organic Compounds 0.0054 LB/MMBTU 0.00540 (VOC) IL-0114 09/05/2014  ACT Boiler 11.31 natural gas 864 MMBTU/H Volatile Organic Compounds good combustion practices 0.0054 LB/MMBTU 0.00540 (VOC) IN-0234 12/08/2015  ACT BOILER 1 11.31 NATURAL GAS 271 MMBTU/H Volatile Organic Compounds GOOD COMBUSTION PRACTICES 0.0015 LB/MMBTU 0.00150 (VOC) IN-0234 12/08/2015  ACT BOILER 2 11.31 NATURAL GAS 271 MMBTU/H Volatile Organic Compounds GOOD COMBUSTION PRACTICES 0.0015 LB/MMBTU 0.00150 (VOC) LA-0248 01/27/2011  ACT DRI-109 - DRI Unit #1 Package 11.31 Natural Gas 1760 Billion Btu/yr Volatile Organic Compounds good combustion practices 1.56 LB/H 0.00540 Boiler Flue Stack (VOC) LA-0248 01/27/2011  ACT DRI-209 - DRI Unit #2 Package 11.31 Natural Gas 1760 Billion Btu/yr Volatile Organic Compounds good combustion practices 1.19 LB/H 0.00540 Boiler Flue Stack (VOC) LA-0254 08/16/2011  ACT AUXILIARY BOILER (AUX-1) 11.31 NATURAL GAS 338 MMBTU/H Methane PROPER OPERATION AND GOOD 0.0022 LB/MMBTU 0.00220 COMBUSTION PRACTICES LA-0254 08/16/2011  ACT AUXILIARY BOILER (AUX-1) 11.31 NATURAL GAS 338 MMBTU/H Volatile Organic Compounds USE OF PIPELINE QUALITY NATURAL GAS 5.5 LB/MMSCF 0.00539 (VOC) AND GOOD COMBUSTION PRACTICES LA-0311 07/15/2013  ACT No. 6 Ammonia Plant Boiler (15- 11.31 Natural Gas 612.4 MM Btu/hr Methane Energy efficiency measures including annual 0.0036 LB/1000 LB 0.00302 13) and No. 5 Urea Boiler (23-13) tuning; use of economizers; optimization of STEAM (EQTs 165 & 175) combustion; instrumentation and controls (temperature sensors, oxygen trim systems); heating incoming combustion air with an air preheater; insulating boilers surfaces; reducing air leakages; employing a condensate return/recovery system; reducing slagging and fouling of heat transfer surfaces; a steam trap/valve maintenance program; good operating and maintenance practices (monitoring air-to-fuel ratio, regular inspections); and pursuing ANSI or ISO certification.

*LA-0312 06/30/2017  ACT B1-13 - Boiler 1 (EQT0003) 11.31 Natural Gas 350 MM BTU/hr Volatile Organic Compounds Good Combustion Practices 1.89 LB/HR 0.00540 (VOC) *LA-0312 06/30/2017  ACT B2-13 - Boiler 2 (EQT0004) 11.31 Natural Gas 350 MM BTU/hr Volatile Organic Compounds Good Combustion Practices 1.89 LB/HR 0.00540 (VOC) *LA-0312 06/30/2017  ACT B2-13-SUSD - Boiler 2 11.31 Natural Gas 515 MMBTU/hr Volatile Organic Compounds Follow manufacturer’s procedures for start-up 0ND Startup/Shutdown (EQT0006) (VOC) and shutdown *LA-0312 06/30/2017  ACT B1-13-SUSD - Boiler 1 11.31 Natural Gas 515 MMBTU/hr Volatile Organic Compounds Follow manufacturer’s procedures for start-up 0ND Startup/Shutdown (EQT0005) (VOC) and shutdown *LA-0315 05/23/2014  ACT Utility Boiler 1 11.31 Natural Gas 656 MMBTU/HR Volatile Organic Compounds Combustion controls (proper burner design and 3.54 LB/H 0.00540 (VOC) operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 2 11.31 Natural Gas 656 MMBTU/HR Volatile Organic Compounds Combustion controls (proper burner design and 3.54 LB/H 0.00540 (VOC) operation using natural gas) *LA-0315 05/23/2014  ACT Utility Boiler 3 11.31 Natural Gas 656 MMBTU/HR Volatile Organic Compounds Combustion controls (proper burner design and 3.54 LB/H 0.00540 (VOC) operation using natural gas) *ND-0033 08/10/2015  ACT Boilers 11.31 Natural gas 187.5 MMBTU/H Volatile Organic Compounds Good Combustion Practices 0.0054 LB/MM BTU 0.00540 (VOC) TX-0635 01/17/2013  ACT Very High Pressure (VHP) Boiler 11.31 Natural Gas 500 MM BTU/H Methane 6.5 T/YR 0.00297

TX-0656 05/16/2014  ACT Boiler 11.31 natural gas and fuel gas 950 MMBTU/H Volatile Organic Compounds clean fuel and good combustion practices 14 T/YR 0.00336 (VOC) TX-0704 12/02/2014  ACT (2) boilers 11.31 natural gas 450 MMBTU/H Volatile Organic Compounds good combustion practices 0.004 LB/MMBTU 0.00400 (VOC) TX-0704 12/02/2014  ACT boiler 11.31 natural gas 250 MMBTU/H Volatile Organic Compounds good combustion practices 0.004 LB/MMBTU 0.00400 (VOC) VA-0320 12/06/2012  ACT NATURAL GAS FIRED BOILERS, 11.31 Natural Gas 400 MMBTU/H Volatile Organic Compounds Good combusion practices 2.2 LB/H 0.00550 (6) (VOC) WI-0267 09/06/2018  ACT Two Natural Gas-Fired Boilers 11.31 Natural Gas 285 mmBtu/hr Volatile Organic Compounds Good combustion practices, only fire natural gas 0.0055 LB/MMBTU 0.00550 (Boilers B34 and B35) (VOC) and/or biogas, equip boilers with low NOx burners and flue gas recirculation.

29 No. of Determinations Minimum 0.0014 Maximum 0.0055

Attachment H, H2-9 Stadardized BACT Determinations for Boilers - Carbon Dioxide Equivalent (CO2e) Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0271 06/11/2014  ACT No.4 Power Boiler 11.31 Natural Gas 425 MMBTU/H Carbon Dioxide Equivalent 117.1 LB/MMBTU 117.10000 (CO2e) *FL-0330 12/01/2011  ACT Boilers (4 - 278 mmbtu/hr each) 11.31 natural gas 0 Carbon Dioxide tuning, optimization, instrumentation and controls, 117 LB/MMBTU 117.00000 insulation, and turbulent flow. IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Carbon Dioxide good combustion practices 117 LB/MMBTU 117.00000 IA-0105 10/26/2012  ACT Auxiliary Boiler 11.31 natural gas 472.4 MMBTU/H Carbon Dioxide Equivalent good combustion practices 51748 TONS/YR ND (CO2e) IA-0106 07/12/2013  ACT Boilers 11.31 natural gas 456 MMBTU/H Carbon Dioxide Equivalent proper operation and use of natural gas 234168 TONS/YR 117.24345 (CO2e) IA-0108 11/07/2013  ACT Boiler 11.31 natural gas 213.6 MMBTU/H Carbon Dioxide Equivalent 113552 TONS 121.37226 (CO2e) IN-0166 06/27/2012  ACT TWO (2) AUXILIARY BOILERS 11.31 NATURAL GAS 408 MMBTU/H, EACH Carbon Dioxide USE OF NATURAL GAS OR SNG; ENERGY 81 % THERMAL ND EFFICIENT BOILER DESIGN (UTILIZING AN EFFICIENCY ECONOMIZER, CONDENSATE RECOVERY, INLET AIR CONTROLS AND BLOWDOWN HEAT RECOVERY.); LA-0254 08/16/2011  ACT AUXILIARY BOILER (AUX-1) 11.31 NATURAL GAS 338 MMBTU/H Carbon Dioxide PROPER OPERATION AND GOOD 117 LB/MMBTU 117.00000 COMBUSTION PRACTICES LA-0266 05/01/2013  ACT Boiler B-101-G (12-1) (EQT 0061) 11.31 Natural gas 359 MMBTU/H Carbon Dioxide Equivalent Energy efficiency measures: improved combustion 0 125.14286 (CO2e) measures (e.g., combustion tuning, optimization using parametric testing, advanced digital instrumentation such as temperature sensors, oxygen monitors, CO monitors, and oxygen trim controls); use of an economizer; boiler insulation; and minimization of air infiltration.

LA-0305 06/30/2016  ACT Auxiliary Boilers and 11.31 Natural Gas 0 Carbon Dioxide Equivalent good equipment design and good combustion 0ND Superheaters (CO2e) practices LA-0311 07/15/2013  ACT No. 6 Ammonia Plant Boiler (15- 11.31 Natural Gas 612.4 MM Btu/hr Carbon Dioxide Equivalent Use of natural gas as fuel and energy efficiency 191.7 LB/1000 LB 136.92857 13) and No. 5 Urea Boiler (23-13) (CO2e) measures, including annual tuning; use of STEAM (EQTs 165 & 175) economizers; optimization of combustion; instrumentation and controls (temperature sensors, oxygen trim systems); heating incoming combustion air with an air preheater; insulating boilers surfaces; reducing air leakages; employing a condensate return/recovery system; reducing slagging and fouling of heat transfer surfaces; a steam trap/valve maintenance program; good operating and maintenance practices (monitoring air-to-fuel ratio, regular inspections); and pursuing ANSI or ISO certification. LA-0311 07/15/2013  ACT No. 6 Ammonia Plant Boiler (15- 11.31 Natural Gas 612.4 MM Btu/hr Carbon Dioxide Use of natural gas as fuel and energy efficiency 191.5 LB/1000 LB 136.78571 13) and No. 5 Urea Boiler (23-13) measures, including annual tuning; use of STEAM (EQTs 165 & 175) economizers; optimization of combustion; instrumentation and controls (temperature sensors, oxygen trim systems); heating incoming combustion air with an air preheater; insulating boilers surfaces; reducing air leakages; employing a condensate return/recovery system; reducing slagging and fouling of heat transfer surfaces; a steam trap/valve maintenance program; good operating and maintenance practices (monitoring air-to-fuel ratio, regular inspections); and pursuing ANSI or ISO certification. *LA-0312 06/30/2017  ACT B1-13 - Boiler 1 (EQT0003) 11.31 Natural Gas 350 MM BTU/hr Carbon Dioxide Equivalent Energy Efficiency Measures: 179511 TON/YEAR 117.09785 (CO2e) *LA-0312 06/30/2017  ACT B2-13 - Boiler 2 (EQT0004) 11.31 Natural Gas 350 MM BTU/hr Carbon Dioxide Equivalent Energy efficiency measures 179511 TPY 117.09785 (CO2e) *LA-0312 06/30/2017  ACT B2-13-SUSD - Boiler 2 11.31 Natural Gas 515 MMBTU/hr Carbon Dioxide Equivalent Follow manufacturer’s procedures for start-up 4339 TPY ND Startup/Shutdown (EQT0006) (CO2e) and shutdown *LA-0312 06/30/2017  ACT B1-13-SUSD - Boiler 1 11.31 Natural Gas 515 MMBTU/hr Carbon Dioxide Equivalent Follow manufacturer’s procedures for start-up 4339 TPY ND Startup/Shutdown (EQT0005) (CO2e) and shutdown *LA-0315 05/23/2014  ACT Utility Boiler 1 11.31 Natural Gas 656 MMBTU/HR Carbon Dioxide Equivalent Energy efficiency measures (air pre-heat) 0 ND (CO2e) *LA-0315 05/23/2014  ACT Utility Boiler 2 11.31 Natural Gas 656 MMBTU/HR Carbon Dioxide Equivalent Energy Efficiency Measures (air pre-heat) 0 ND (CO2e) *LA-0315 05/23/2014  ACT Utility Boiler 3 11.31 Natural Gas 656 MMBTU/HR Carbon Dioxide Equivalent Energy Efficiency Measures (air pre-heat) 0 ND (CO2e) LA-0323 01/09/2017  ACT No. 9 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Carbon Dioxide Equivalent Good combustion practices and energy efficient 0.167 LB/LB 119.28571 (CO2e) operation LA-0323 01/09/2017  ACT No. 10 Boiler - Natural Gas Fired 11.31 Natural Gas 325 MMBTU/h Carbon Dioxide Equivalent Good combustion practices and energy efficient 0.167 LB/LB 119.28571 (CO2e) operation MN-0088 05/22/2013  ACT NATURAL GAS-FIRED BOILER 11.31 NATURAL GAS 257.3 MMBTU/H Carbon Dioxide Equivalent LIMITED TO NATURAL GAS BY DESIGN. 117800 T/YR 104.52770 (CO2e) REQUIRED TO BE EQUIPPED WITH AN ECONOMIZER AND AN OXYGEN TRIM SYSTEM. ND-0032 06/20/2014  ACT Package boiler 11.31 Natural gas 280 MMBTU/H Carbon Dioxide Equivalent good combustion practices 143501 TONS 117.00995 (CO2e) *ND-0033 08/10/2015  ACT Boilers 11.31 Natural gas 187.5 MMBTU/H Carbon Dioxide Equivalent Fuel Efficiency Techniques 59675 TONS/YEAR ND (CO2e) CO2E NE-0054 09/12/2013  ACT Boiler K 11.31 natural gas 300 mmbtu/h Carbon Dioxide Equivalent good combustion practices 153743 TON/YEAR 117.00381 (CO2e)

Attachment H, H2-10 Stadardized BACT Determinations for Boilers - Carbon Dioxide Equivalent (CO2e) Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu NY-0119 05/02/2014  ACT Boilers - NG 11.31 natural gas 0 Carbon Dioxide Equivalent GHG BACT shall be demonstrated by the use of low 0ND (CO2e) CO2 emitting fuel (i.e., natural gas), the performance of an annual boiler tune-up, and execution of the efficiency improvement plan. The efficiency improvement plan includes the application of the following measures: oxygen trim control, economizer, optimizing blowdown based on the total dissolved solids content of the feedwater, condensate return, steam pipe insulation, optimization of the steam distribution network, and routine inspection of the steam network to detect and fix any leaks in the system. The facility shall keep a logbook documenting annual tune-ups and efficiency improvement plan activities.

OK-0162 05/29/2014  ACT Boiler 11.31 Natural Gas 450 MMBTUH Carbon Dioxide Equivalent Efficient Design, Air Preheaters 117 LB/MMBTU 117.00000 (CO2e) TX-0635 01/17/2013  ACT Very High Pressure (VHP) Boiler 11.31 Natural Gas 500 MM BTU/H Carbon Dioxide 127000 T/YR ND

TX-0739 11/21/2013  ACT Boiler equipped with SCR 11.31 Pipeline Nat Gas and 550 MMBTU/H Carbon Dioxide Equivalent 117 LB 117.00000 90/10 blend (CO2e) CO2/MMBTU TX-0744 06/12/2014  ACT Boiler equipped with SCR and 11.31 Pipeline Nat Gas or 615 MMBTU/H Carbon Dioxide Equivalent 82 % THERMAL 122.52849 ultra-low NOx burners Process Gas (CO2e) EFFICIENCY WI-0258 06/10/2013  ACT B08 - Up to 253 MMBtu/hour 11.31 Natural Gas 253 MMBtu/hour Carbon Dioxide Equivalent 0ND Natural Gas Fired Boiler (CO2e) WI-0267 09/06/2018  ACT Two Natural Gas-Fired Boilers 11.31 Natural Gas 285 mmBtu/hr Carbon Dioxide Equivalent Good combustion practices, only fire natural gas, 160 LBCO2E/1000 114.28571 (Boilers B34 and B35) (CO2e) equip boilers with low NOx burners and flue gas LB STEAM recirculation

32 No. of Determinations Minimum 105 Maximum 137

Attachment H, H2-11 Stadardized BACT Determinations for Ore Crushing - Particulates Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT gr/dscf *AK-0084 06/30/2017  ACT Ore Crushing and Transfers 90.021 5100 tph Particulate matter, total (TPM) Enclosures 0.0005 GR/DSCF 0.00050 (Enclosures) *AK-0084 06/30/2017  ACT Ore Crushing and Transfers (Dust 90.021 5100 tph Particulate matter, total (TPM) Dust Collector 0.01 GR/DSCF 0.01000 Collector) CO-0074 07/09/2012  ACT Material processing & 90.028 0 Particulate matter, filterable < Plant 0.005 GR/DSCF 0.00500 transfer 10 µ (FPM10) Fabric filters combined with enclosed transfer points was selected as BACT.

Quarry The combination of high material moisture content and partial enclosure was selected as BACT. IN-0166 06/27/2012  ACT INCOMING SOLID FEEDSTOCK 90.011 750 T/H Particulate matter, filterable WET OR CHEMICAL SUPPRESSION 90 % CONTROL ND MATERIAL HANDLING (FPM) SYSTEM - BARGE UNLOADING TO HOPPER TRANSFER POINT

IN-0166 06/27/2012  ACT BARGE UNLOADING FROM 90.011 750 T/H Particulate matter, filterable WET DUST EXTRACTION OR A BAGHOUSE 0.003 GR/DSCF 0.00300 THE HOPPER TO THE BELT (FPM) AND BARGE CONVEYOR TRANSFER POINTS IN-0166 06/27/2012  ACT BARGE UNLOADING FROM 90.011 750 T/H Particulate matter, total < 2.5 WET DUST EXTRACTION OR A BAGHOUSE 0.0015 GR/DSCF 0.00150 THE HOPPER TO THE BELT µ (TPM2.5) AND BARGE CONVEYOR TRANSFER POINTS IN-0166 06/27/2012  ACT TRANSFER SYSTEMS 90.011 750 T/H Particulate matter, filterable WET DUST EXTRACTION OR A BAGHOUSE 0.003 GR/DSCF 0.00300 CONSISTING OF HOPPERS (FPM) AND CONVEYOR BELTS TRANSFERRING FEED STOCK FROM THE PILES TO CLASSIFICATION TOWERS; CLASSIFICATION TOWERS; AND IN-0166 06/27/2012  ACT TRANSFER SYSTEMS 90.011 750 T/H Particulate matter, total < 2.5 WET DUST EXTRACTION OR A BAGHOUSE 0.0015 GR/DSCF 0.00150 CONSISTING OF HOPPERS µ (TPM2.5) AND CONVEYOR BELTS TRANSFERRING FEED STOCK FROM THE PILES TO CLASSIFICATION TOWERS; CLASSIFICATION TOWERS; AND IN-0166 06/27/2012  ACT TRUCK/RAIL CONVEYOR 90.011 750 T/H Particulate matter, filterable ENCLOSED VENT TO A DUST EXTRACTION 0.003 GR/DSCF 0.00300 TRANSFER TOWER; TRUCK (FPM) SYSTEM OR BAGHOUSE STATIONS UNLOADING TO A TRUCK HOPPER; AND TRUCK HOPPER UNLOADING TO THE CONVEYOR BELTS

IN-0166 06/27/2012  ACT TRUCK/RAIL CONVEYOR 90.011 750 T/H Particulate matter, total < 2.5 ENCLOSED VENT TO A DUST EXTRACTION 0.0015 GR/DSCF 0.00150 TRANSFER TOWER; TRUCK µ (TPM2.5) SYSTEM OR BAGHOUSE STATIONS UNLOADING TO A TRUCK HOPPER; AND TRUCK HOPPER UNLOADING TO THE CONVEYOR BELTS

IN-0167 04/16/2013  ACT IRON ORE CONCENTRATE 90.021 4950 T/H Particulate matter, filterable DEVELOPMENT, MAINTENANCE, AND 3.93 LB/H ND TRANSFER AND SROAGE (FPM) IMPLEMENTATION OF SITE-SPECIFIC AREA FUGITIVE DUST CONTROL PLAN AND ENCLOSURE IN-0167 04/16/2013  ACT LIMESTONE/DOLOMITE 90.019 495 T/H Particulate matter, filterable THROUGH THE DEVELOPMENT, 0.9 LB/H ND HOPPER, BELT FEEDER, (FPM) MAINTENANCE, AND IMPLEMENTATION GRIZZLY FEEDER/SCREENER OF A SITE-SPECIFIC FUGITIVE DUST CONTROL PLAN IN-0185 04/24/2014  ACT IRON CONCENTRATE 90.021 4950 T/H Particulate matter, filterable < 3.14 LB/H ND TRANSFER AND STORAGE 10 µ (FPM10) AREA IN-0185 04/24/2014  ACT LIMESTONE/DOLOMITE 90.019 495 T/H Particulate matter, filterable 0.9 LB/H ND HOPPER, BELT FEEDER & (FPM) GRIZZLY FEEDER/SCREENER KY-0100 04/09/2010  ACT COAL CRUSHING AND SILO 90.011 0 Particulate matter, filterable < FABRIC FILTER 0.005 GR/DSCF 0.00500 STORAGE 10 µ (FPM10) MI-0400 06/29/2011  ACT Coal crushers 90.011 0 Particulate matter, filterable Fabric filter dust collector. 2 E-5 GR/DSCF 0.00002 (EUFUELCRUSHER) (FPM) MN-0084 12/06/2011  ACT FINAL TRANSFER 90.031 0 Particulate Matter (PM) BAGHOUSE W/ LEAK DETECTION 0.21 LB/H 0.00200 CONVEYORS AND LOADOUT CONVEYOR MN-0084 12/06/2011  ACT PELLET SCREENING SYSTEM 90.031 0 Particulate Matter (PM) WET SCRUBBER 3.2 LB/H 0.00500 AND SAMPLER MN-0084 12/06/2011  ACT EMERGENCY PELLET 90.031 0 Particulate Matter (PM) BAGHOUSE W/ LEAK DETECTION 0.21 LB/H 0.00200 CONVEYOR TRANSFER, PHASE III MN-0085 05/10/2012  ACT PELLET SCREENING AND 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 HANDLING MN-0085 05/10/2012  ACT PELLET SCREENINGS TO 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 REGRIND CONVEYORS MN-0085 05/10/2012  ACT GRIZZLY TRANSFER TOWER 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 MN-0085 05/10/2012  ACT NON-MAGNETIC COBBER 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 REJECTS TRANSFER TOWER Attachment H, H2-12 Stadardized BACT Determinations for Ore Crushing - Particulates Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT gr/dscf MN-0085 05/10/2012  ACT SECONDARY SCREENING 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 CRUSHER/COBBER LINE 1 MN-0085 05/10/2012  ACT SECONDARY SCREENING 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 CRUSHER/COBBER LINE 2 MN-0085 05/10/2012  ACT SECONDARY SCREENING 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 CRUSHER/COBBER LINE 3 MN-0085 05/10/2012  ACT SECONDARY SCREENING 90.031 0 Particulate Matter (PM) FABRIC FILTER WITH LEAK DETECTION 0.002 GR/DSCF 0.00200 CRUSHER/COBBER LINE 4 MO-0089 05/12/2016  ACT urea, sorbent, fly ash transfer 90.022 0 Particulate matter, filterable baghouse 0 GR/DSCF ND (FPM) OH-0310 10/08/2009  ACT COAL CONVEYING, 90.011 5553840 T/YR Particulate matter, filterable < BAGHOUSE WITH OPTION OF 9T/YRND HANDLING, AND CRUSHING 10 µ (FPM10) ENCLOSURES, FOGGING, WET SUPPRESSION OH-0310 10/08/2009  ACT COAL CONVEYING, 90.011 5553840 T/YR Particulate Matter (PM) 77.6 LB/H ND HANDLING, AND CRUSHING TX-0822 06/30/2017  ACT Material Handling, Transport, 90.028 0 Particulate matter, total (TPM) BAGHOUSE 0.01 GR/DSCF 0.01000 and Transfer Sources TX-0831 12/06/2017  ACT Portland Cement Kiln: Material 90.028 3300 TON CLINKER/DAY Particulate matter, total (TPM) BAGHOUSE 0.01 GR/DSCF 0.01000 Handling, Transport, and Transfer Sources WI-0262 06/30/2017  ACT Coal crusher house, P06 90.011 PRB Coal 1600 tons per hour Particulate matter, total (TPM) Building enclosure. New dust collection 1.12 LBS/HR 0.00200 system, new baghouse. *WY-0078 03/27/2017  ACT DC-08C Crusher Bldg Screens, 4C- 90.017 0 Particulate matter, filterable baghouse 0.24 LB/H 0.00200 36 and 4C-37A (FPM) *WY-0078 03/27/2017  ACT DC-09A Crusher Bldg, 90.017 0 Particulate matter, filterable baghouse 0.1 LB/H 0.00200 Housekeeping C-24, 4C-28 and (FPM) 4C-29 *WY-0078 03/27/2017  ACT DC-37 No. 3 Shaft Ore Screening 90.017 0 Particulate matter, filterable Baghouse 0.46 LB/H 0.00200 Bldg (FPM) *WY-0078 03/27/2017  ACT DC-52 Dust to DECA Transfer 90.017 0 Particulate matter, filterable baghouse 0.19 LB/H 0.00200 (FPM) *WY-0078 03/27/2017  ACT DC-54 7C26 A to B Transfer 90.017 0 Particulate matter, filterable Baghouse 0.19 LB/H 0.00200 (FPM) *WY-0078 03/27/2017  ACT DC-55 7C26 B to C Transfer 90.017 0 Particulate matter, filterable Baghouse 0.14 LB/H 0.00200 (FPM) *WY-0078 03/27/2017  ACT DC-56 S4 Screens 90.017 0 Particulate matter, filterable Baghouse 0.43 LB/H 0.00200 (FPM) *WY-0078 03/27/2017  ACT DC-57 S1 and S2 Screens 90.017 0 Particulate matter, filterable Baghouse 0.6 LB/H 0.00200 (FPM)

41 No. of Determinations Minimum 0.00002 Maximum 0.01

Attachment H, H2-13 Stadardized BACT Determinations for Dryer - Carbon Monoxide Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0287 03/25/2010  ACT Line 1 Post-Dryer (S31) 81.29 Natural Gas 7.7 MMBTU/H Carbon Monoxide 0.06 LB/MMBTU 0.06000 AL-0288 03/25/2010  ACT Line 2 Post - Dryer (S32) 81.29 Natural Gas 7.7 MMBTU/H Carbon Monoxide 0.06 LB/MMBTU 0.06000 AL-0289 03/25/2010  ACT Line 3 Post - Dryer (S33) 81.29 Natural Gas 7.7 MMBTU/H Carbon Monoxide 0.06 LB/MMBTU 0.06000 AL-0291 03/25/2010  ACT Line 4 Post - Dryer (S34) 81.29 Natural Gas 7.7 MMBTU/H Carbon Monoxide 0.06 LB/MMBTU 0.06000 AL-0307 10/09/2015  ACT TWO 4.44 MMBTU/HR STRIP 82.129 NATURAL GAS 4.44 MMBTU/H Carbon Monoxide GCP 0 ND DRYERS AL-0307 10/09/2015  ACT TWO 1.37 MMBTU/HR STRIP 82.129 NATURAL GAS 1.37 MMBTU/H Carbon Monoxide GCP 0.03 LB/MMBTU 0.03000 DRYERS AR-0140 09/18/2013  ACT DRYERS, MGO COATING LINE 81.29 NATURAL GAS 38 MMBTU/H Carbon Monoxide COMBUSTION OF NATURAL GAS AND GOOD 0.0824 LB/MMBTU 0.08240 COMBUSTION PRACTICE GA-0145 04/06/2012  ACT SPRAY DRYER 90.017 NATURAL GAS 47 MMBTU/H Carbon Monoxide GOOD COMBUTIONS TECHNIQUES. 16.6 LB/H 0.35319 GA-0147 01/27/2012  ACT SPRAY DRYERS/PETTETIZERS 90.009 NATURAL GAS 75 MMBTU/H Carbon Monoxide GOOD COMBUSTION TECHNOLOGY AND 13.73 LB/H EA 0.18307 PRACTICE LA-0239 05/24/2010  ACT SLG-402 - SLAG MILL DRYER 81.29 NATURAL GAS 75.4 T/H Carbon Monoxide GOOD COMBUSTION PRACTICES 2.26 LB/H 0.11200 STACK *WY-0078 03/27/2017  ACT Unit 4 Dryer 90.017 natural gas 1138800 tpy Carbon Monoxide good combustion practices 120 LB/H 0.84000

11 No. of Determinations Minimum 0.03 Maximum 0.84

Attachment H, H2-14 Stadardized BACT Determinations for Dryer - Particulates Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT gr/dscf AL-0287 03/25/2010  ACT Line 1 Post-Dryer (S31) 81.29 Natural Gas 7.7 MMBTU/H Particulate matter, filterable 0.0076 LB/MMBTU ND (FPM) AL-0288 03/25/2010  ACT Line 2 Post - Dryer (S32) 81.29 Natural Gas 7.7 MMBTU/H Particulate matter, filterable 0.0076 LB/MMBTU ND (FPM) AL-0289 03/25/2010  ACT Line 3 Post - Dryer (S33) 81.29 Natural Gas 7.7 MMBTU/H Particulate matter, filterable 0.0076 LB/MMBTU ND (FPM) AL-0291 03/25/2010  ACT Line 4 Post - Dryer (S34) 81.29 Natural Gas 7.7 MMBTU/H Particulate matter, filterable 0.0076 LB/MMBTU ND (FPM) AR-0140 09/18/2013  ACT DRYERS, MGO COATING LINE 81.29 NATURAL GAS 38 MMBTU/H Particulate matter, filterable COMBUSTION OF NATURAL GAS AND 5.2 X10^-4 ND (FPM) GOOD COMBUSTION PRACTICE LB/MMBTU GA-0145 04/06/2012  ACT SPRAY DRYER 90.017 NATURAL GAS 47 MMBTU/H Particulate matter, filterable < BAGHOUSE 0.02 GR/DSCF 0.02000 10 µ (FPM10) GA-0145 04/06/2012  ACT SPRAY DRYER 90.017 NATURAL GAS 47 MMBTU/H Particulate matter, filterable BAGHOUSE 0.01 GR/DSCF 0.01000 (FPM) GA-0145 04/06/2012  ACT SPRAY DRYER 90.017 NATURAL GAS 47 MMBTU/H Particulate matter, filterable < BAGHOUSE 0.0075 GR/DSCF 0.00750 2.5 µ (FPM2.5) GA-0147 01/27/2012  ACT SPRAY DRYERS/PETTETIZERS 90.009 NATURAL GAS 75 MMBTU/H Particulate matter, filterable FABRIC BAGHOUSE 0.006 GR/DSCF 0.00600 (FPM) LA-0239 05/24/2010  ACT SLG-402 - SLAG MILL DRYER 81.29 NATURAL GAS 75.4 T/H Particulate matter, total (TPM) BACT is selected to be good combustion 0.2 LB/H ND STACK practices during the operation of the dryer *WY-0078 03/27/2017  ACT Unit 4 Dryer 90.017 natural gas 1138800 tpy Particulate matter, total (TPM) wet scrubber 49.5 LB/H 0.10000

11 No. of Determinations Minimum 0.006 Maximum 0.1

Attachment H, H2-15 Stadardized BACT Determinations for Dryer - Volatile Organic Compounds Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0287 03/25/2010  ACT Line 1 Post-Dryer (S31) 81.29 Natural Gas 7.7 MMBTU/H Volatile Organic Compounds 0.0055 LB/MMBTU 0.00550 (VOC) AL-0288 03/25/2010  ACT Line 2 Post - Dryer (S32) 81.29 Natural Gas 7.7 MMBTU/H Volatile Organic Compounds 0.0055 LB.MMBTU 0.00550 (VOC) AL-0289 03/25/2010  ACT Line 3 Post - Dryer (S33) 81.29 Natural Gas 7.7 MMBTU/H Volatile Organic Compounds 0.0055 LB/MMBTU 0.00550 (VOC) AL-0291 03/25/2010  ACT Line 4 Post - Dryer (S34) 81.29 Natural Gas 7.7 MMBTU/H Volatile Organic Compounds 0.0055 LB/MMBTU 0.00550 (VOC) AL-0307 10/09/2015  ACT TWO 1.37 MMBTU/HR STRIP 82.129 NATURAL GAS 1.37 MMBTU/H Volatile Organic Compounds GCP 0.006 LB/MMBTU 0.00600 DRYERS (VOC) AR-0140 09/18/2013  ACT DRYERS, MGO COATING LINE 81.29 NATURAL GAS 38 MMBTU/H Volatile Organic Compounds COMBUSTION OF NATURAL GAS AND GOOD 0.0054 LB/MMBTU 0.00540 (VOC) COMBUSTION PRACTICE GA-0145 04/06/2012  ACT SPRAY DRYER 90.017 NATURAL GAS 47 MMBTU/H Volatile Organic Compounds 6.82 T/YR ND (VOC) GA-0147 01/27/2012  ACT SPRAY DRYERS/PETTETIZERS 90.009 NATURAL GAS 75 MMBTU/H Volatile Organic Compounds Use of Natural Gas and propane as fuel 11.78 LB/H 0.15707 (VOC) IN-0290 08/13/2018  ACT board, kiln, dryer 90.019 NATURAL GAS 433000 T/YR Volatile Organic Compounds 0.1 LB/T ND (VOC) LA-0239 05/24/2010  ACT SLG-402 - SLAG MILL DRYER 81.29 NATURAL GAS 75.4 T/H Volatile Organic Compounds GOOD COMBUSTION PRACTICES 0.15 LB/H 0.00730 STACK (VOC)

10 No. of Determinations Minimum 0.0054 Maximum 0.16

Attachment H, H2-16 Stadardized BACT Determinations for Dryer - Carbon Dioxide Equivalent (CO2e) Limit EMISSION EMISSION RBLCID PERMIT ISSUANCE DATE PROCESS NAME PROCESS TYPE PRIMARY FUEL THROUGHPUT THROUGHPUT UNIT POLLUTANT CONTROL METHOD DESCRIPTION LIMIT 1 LIMIT 1 UNIT lb/MMBtu AL-0307 10/09/2015  ACT TWO 4.44 MMBTU/HR STRIP 82.129 NATURAL GAS 4.44 MMBTU/H Carbon Dioxide Equivalent 36251 T/YR ND DRYERS (CO2e) AL-0307 10/09/2015  ACT TWO 1.37 MMBTU/HR STRIP 82.129 NATURAL GAS 1.37 MMBTU/H Carbon Dioxide Equivalent 36251 T/YR ND DRYERS (CO2e) AR-0140 09/18/2013  ACT DRYERS, MGO COATING LINE 81.29 NATURAL GAS 38 MMBTU/H Carbon Dioxide GOOD OPERATING PRACTICES 117 LB/MMBTU 117.00000

FL-0342 07/18/2014  ACT Fuel dryer 90.019 Natural gas 3.5 MMBTU/H Carbon Dioxide Equivalent Usage of natural gas is low-GHG. Good combustion 1795 TON/YR 117.09067 (CO2e) work practice standard ensures efficiency.

GA-0147 01/27/2012  ACT SPRAY DRYERS/PETTETIZERS 90.009 NATURAL GAS 75 MMBTU/H Carbon Dioxide Equivalent Good Heating Insulation, Good Combustion 44446 T/12-MO 135.29985 (CO2e) Practices ROLLING AVG *WY-0078 03/27/2017  ACT Unit 4 Dryer 90.017 natural gas 1138800 tpy Carbon Dioxide Equivalent 73342 TPY 117.09615 (CO2e)

6 No. of Determinations Minimum 117 Maximum 135

Attachment H, H2-17

Attachment H3 – BACT Cost Calculations

Appendix H, Page H3-1 Table of Contents

BACT Cost Calculations BACT Cost Calculations ...... Attachment H3

Catalytic Oxidizer Cost Estimate ...... H3-3 Regenerative Thermal Oxidizer Cost Estimate...... H3-5

Appendix H, Page H3-2 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 1 3 BACT$ AIR EMISSION CALCULATIONS SUBJECT: DATE: BACT Control Cost February 26, 2019

Catalytic Oxidizer Cost Estimate

NOTE: Fixed-bed catalytic incinerator cost estimations in EPA Air Pollution Control Cost Manual are provided for flow rates from 2,000-50,000 scfm.

Flow (scfm) 76,425 42,800 Direct Costs Purchased equipment costs Ref Incinerator Equipment cost (EC), 1988 dollars = A a $ 721,000 $ 524,000 Instrumentation 0.1*A 0.1 b$ 72,100 $ 52,400 Sales tax 0.03*A 0.03 b$ 21,630 $ 15,720 Freight 0.05*A 0.05 b$ 36,050 $ 26,200 Purchased equipment cost (PEC) = B $ 851,000 $ 618,000

Direct installation costs Foundations and supports 0.08*B 0.08 b$ 68,080 $ 49,440 Handling and erection 0.14*B 0.14 b$ 119,140 $ 86,520 Electrical 0.04*B 0.04 b$ 34,040 $ 24,720 Piping 0.02*B 0.02 b$ 17,020 $ 12,360 Insulation for ductwork 0.01*B 0.01 b $ 8,510 $ 6,180 Painting 0.01*B 0.01 b $ 8,510 $ 6,180 Direct installation costs $ 255,000 $ 185,000 Total Direct Cost (DC) $ 1,106,000 $ 803,000

Indirect Costs (installation) Engineering 0.1*B 0.1 c $ 85,100 $ 61,800 Construction and field expenses 0.05*B 0.05 c $ 42,550 $ 30,900 Contractor fees 0.1*B 0.1 c $ 85,100 $ 61,800 Start-up 0.02*B 0.02 c $ 17,020 $ 12,360 Performance test 0.01*B 0.01 c $ 8,510 $ 6,180 Total Indirect Costs (IC) $ 238,000 $ 173,000

Total Direct and Indirect Costs (DC+IC) $ 1,344,000 $ 976,000 Contingency Cost (CC) 0.15*(DC+IC) 0.15 d $ 201,600 $ 146,400 Total Capital Investment (TCI) = DC+IC+CC $ 1,545,600 $ 1,122,400 Escalation Factor (1988 - 2019) 2.14 2.14 CPI Inflation Calculator, 04/88-02/19 Inflation-adjusted TCI $ 3,308,000 $ 2,402,000

Reference a. EPA Air Control Cost Manual Chapter 2 , November 2017, p. 2-43, eq. 2.37: EC = 1443 * (Qtot)0.5527 b. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.10, p. 2-47 c. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.10, p. 2-48 d. The higher end of the range (0.05 to 0.15) is used to account for the additional installation cost associated with a retrofit project. EPA Air Control Cost Manual Chapter 2 , November 2017, p. 2-46

Appendix H, Page H3-3 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 2 3 BACT$ AIR EMISSION CALCULATIONS SUBJECT: DATE: BACT Control Cost February 26, 2019

Catalytic Oxidizer Cost Estimate (continued)

Values from example problem Ref Total Capital Investment (TCI) $ 961,000 a Direct Annual Cost + Overhead $ 203,300 a (DAC+OH)/TCI 0.212 Admin, tax, ins 0.04 a Catalyst Replacement $ 6,423 a Catalyst Replacement/TCI 0.00668

Calculated annual costs, 76,425 scfm Total Capital Investment (TCI) $ 1,545,600 Direct Annual Cost + Overhead $ 326,972 Admin, tax, ins $ 61,824 Catalyst Replacement $ 10,330 Capital Recovery Cost Factor (CRF) 0.0752 b Capital recovery $ 115,390 a Total Annual Cost $ 504,187 Escalation Factor (1988 - 2019) 2.14 CPI Inflation Calculator, 04/88-02/19 Inflation-adjusted Total Annual Cost $ 1,078,959

CO BACT Limit Control Controlled An. Cost Cost Eff. Unit MMBtu/hr lb/MMBtu hr/yr Efficiency ton/yr $/yr $/ton #18 387 0.074 8,760 90% 112.89$ 1,078,959 $9,558 #19 387 0.074 8,760 90% 112.89$ 1,078,959 $9,558

Reference a. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.12, p. 2-52 b. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.12, p. 2-52, footnote c: 20 year life at 4.25% CRF=0.0752

Appendix H, Page H3-4 PROJECT TITLE: BY: Air Sciences Inc. Solvay ARGO K. Lewis PROJECT NO: PAGE: OF: SHEET: 170-18-1 3 3 BACT$ AIR EMISSION CALCULATIONS SUBJECT: DATE: BACT Control Cost February 26, 2019

Regenerative Thermal Oxidizer Cost Estimate

Flow 170,600 scfm NOTE: Regenerative thermal oxidizer cost estimations in EPA Air Pollution Control Cost Manual are provided for flow rates from 10,000-100,000 scfm.

Direct Costs Purchased equipment costs Ref Incinerator Equipment cost (EC), 1988 dollars = A a $ 2,611,000 Instrumentation 0.1*A 0.1 b$ 261,100 Sales tax 0.03*A 0.03 b$ 78,330 Freight 0.05*A 0.05 b$ 130,550 Purchased equipment cost (PEC) = B $ 3,081,000

Direct installation costs Foundations and supports 0.08*B 0.08 b$ 246,480 Handling and erection 0.14*B 0.14 b$ 431,340 Electrical 0.04*B 0.04 b$ 123,240 Piping 0.02*B 0.02 b$ 61,620 Insulation for ductwork 0.01*B 0.01 b$ 30,810 Painting 0.01*B 0.01 b$ 30,810 Direct installation costs $ 924,000 Total Direct Cost (DC) $ 4,005,000

Indirect Costs (installation) Engineering 0.1*B 0.1 c$ 308,100 Construction and field expenses 0.05*B 0.05 c$ 154,050 Contractor fees 0.1*B 0.1 c$ 308,100 Start-up 0.02*B 0.02 c$ 61,620 Performance test 0.01*B 0.01 c$ 30,810 Total Indirect Costs (IC) $ 863,000

Total Direct and Indirect Costs (DC+IC) $ 4,868,000 Contingency Cost (CC) 0.15*(DC+IC) 0.15 d$ 730,200 Total Capital Investment (TCI) = DC+IC+CC $ 5,598,200 Escalation Factor (1988 - 2019) 2.14 CPI Inflation Calculator, 04/88-02/19 Inflation-adjusted TCI $ 11,980,000

Reference

a. EPA Air Control Cost Manual Chapter 2 , November 2017, p. 2-43, eq. 2.33: EC = 2.264 * 105 + 13.98 Qtot b. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.10, p. 2-47 c. EPA Air Control Cost Manual Chapter 2 , November 2017, Table 2.10, p. 2-48 d. The higher end of the range (0.05 to 0.15) is used to account for the additional installation cost associated with a retrofit project. EPA Air Control Cost Manual Chapter 2 , November 2017, p. 2-46

Appendix H, Page H3-5