### MN Taconite FIP Document Locator

I. State Submittals I.A. Minnesota Regional Haze State Implementation Plan (SIP) Submittal, December 30, 2009 I.B. Minnesota Supplemental Regional Haze SIP Submittal, May 8, 2012 II. Best Available Retrofit Technology (BART) Analyses Submitted to State by Facilities II.A. ArcelorMittal, September 8, 2006 II.B. Hibbing, September 2006 II.C. Northshore, September 2006 II.D. United Taconite, September 2006 II.E. U.S. Steel Keetac, September 8, 2006 II.F. U.S. Steel Minntac, September 8, 2006

III. 114 Information

III.A. ArcelorMittal III.A.1. ArcelorMittal 114 Cover Letter, May 9, 2012 III.A.2. ArcelorMittal Item 1 Response III.A.2.a. ArcelorMittal Facility Overview III.A.2.b. ArcelorMittal Indurating Furnace Schematic III.A.3. ArcelorMittal Item 2 Response III.A.3.a. ArcelorMittal Flue Gas Composition, Pellet Residence Time and Air Flow Rate Data III.A.3.b. ArcelorMittal Temperature Data III.A.4. ArcelorMittal Item 3 Response III.A.4.a. ArcelorMittal Natural Gas Usage III.A.5. ArcelorMittal Item 5 Response III.A.5.a. ArcelorMittal 2005 Indurating Furnace Stack Test: NOx III.A.5.b. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.c. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.d. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.e. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.f. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.g. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.h. ArcelorMittal 2006 Stack Test: NOx, SO2 and CO III.A.5.i. ArcelorMittal 2006 Stack Test for Taconite MACT Particulate Compliance III.A.5.j. ArcelorMittal Notice of Compliance Letter from Minnesota Pollution Control Agency (MPCA) for 2006 Stack Test for Taconite MACT Particulate Compliance III.A.5.k. ArcelorMittal 2007 Indurating Furnace Stack Test: Particulate Matter, NOx, SO2, and CO III.A.5.l. ArcelorMittal 2008 Indurating Furnace Stack Test: NOx III.A.5.m. ArcelorMittal 2008 Indurating Furnace Stack Test: SO2 III.A.5.n. ArcelorMittal 2009 Indurating Furnace Stack Test: SO2 III.A.5.o. ArcelorMittal 2009 Indurating Furnace Stack Test: NOx III.A.5.p. ArcelorMittal 2011 Indurating Furnace Stack Test: SO2 III.A.5.q. ArcelorMittal 2009 Indurating Furnace Stack Test: NOx III.A.5.r. ArcelorMittal 2011 MACT Particulate Compliance Tests III.A.6. ArcelorMittal Item 6 Response

III.A.6.a. ArcelorMittal Potential To Emit Calculations for NOx and SO2 III.A.7. ArcelorMittal Item 7 Response III.A.7.a. ArcelorMittal – MPCA Study Entitled “Evaluation of Minnesota Taconite Wet Scrubbers at Minntac, Keewatub Taconite, Hibbing Taconite, and United Taconite” III.A.7.b. ArcelorMittal – MPCA Form GI05A III.A.7.c. ArcelorMittal – Statistical Analysis of SO2 Data from 2008 Stack Test III.A.7.d. ArcelorMittal – Memorandum Explaining the Source of Sulfur from Each Process III.A.8. ArcelorMittal Item 8 Response III.A.8.a. ArcelorMittal – Summary of Conversation with Danieli-Corus on NOx Study and Low NOx Burner Retrofitpage 2 of 10

III.A.8.b. ArcelorMittal – MPCA/Barr Engineering Report Entitlted “Potential Impacts of the Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry In Minnesota” III.A.8.c. ArcelorMittal – Barr Email Regarding Low NOx Burners, April 27, 2012 III.A.8.d. ArcelorMittal – Proposal and Preliminary Data from EPS Technologies, Inc. Investigating the use of a catalyst, CFD24-7 III.B. Hibbing III.B.1. Hibing 114 Cover Letter, May 4, 2012 III.B.2. Hibbing Summary of Response III.B.3. Hibbing Item 1 Response III.B.3.a. Hibbing Photographical Process Diagram III.B.3.b. Hibbing Process Diagram III.B.4. Hibbing Item 2 Response III.B.4.a. Hibbing Flue Gas Composition III.B.4.b. Hibbing 2010-2011 Process Data III.B.5. Hibbing Item 3 Response III.B.5.a. Hibbing 2007-2011 Gas Use III.B.6. Hibbing Item 5 Response III.B.6.a. Hibbing 1987 Stack Test: PM, NOx, SO2, CO, Pb, Orsat, Moisture, Beryllium III.B.6.b. Hibbing 1994 Stack Test, Lines 1 and 2: PM, NOx, SO2, CO, Pb, VOC, Opacity, Total Hydrocarbon, TSP III.B.6.c. Hibbing 1994 Stack Test, Line 2: PM, NOx, SO2, CO, Pb, VOC, Opacity, TSP III.B.6.d. Hibbing 1994 Stack Test, Line 3: PM, NOx, SO2, CO, Pb, VOC, Opacity III.B.6.e. Hibbing 1997 Stack Test, Lines 1, 2, and 3: NOx, CO2, O2 III.B.6.f. Hibbing 1999 Stack Test, Line 2: PM, NOx, SO2, CO, Pb, VOC, Opacity III.B.6.g. Hibbing 1999 Stack Test, Line 3: PM, NOx, SO2, CO, Pb, VOC III.B.6.h. Hibbing 2004 Stack Test, Line 2: PM, NOx, SO2, CO, Pb, VOC, Opacity III.B.6.i. Hibbing 2005 Stack Test, Lines 1 and 3: PM, NOx, SO2, CO, VOC, Opacity III.B.6.j. Hibbing 2007 Stack Test, Lines 1, 2, and 3: NOx III.B.6.k. Hibbing 2007 Stack Test, Line 2: NOx III.B.6.l. Hibbing Forced Conditions from Line 2, 2007 NOx Stack Test III.B.6.m. Hibbing 2008 Stack Test, Lines 1 and 3: NOx III.B.6.n. Hibbing 2008 Line 1 NOx CEMS, pounds per hour III.B.6.o. Hibbing 2008 Line 3 NOx CEMS, pounds per hour III.B.6.p. Hibbing 2010 Stack Test, Lines 1, 2, and 3: NOx III.B.6.q. Hibbing 2010 Stack Test Lines 1, 2, and 3: PM, NOx, SO2, CO, Pb, VOC, Opacity III.B.6.r. Hibbing 2010 Line 1 NOx Stack Test and Lines 1 and 2 Predictive Emissions Monitoring Systems (PEMS) Relative Accuracy Test Audits (RATA) III.B.6.s. Hibbing Line 1 PEMS Spreadsheet III.B.6.t. Hibbing Line 2 PEMS Spreadsheet III.B.6.u. Hibbing 2010 Line 1 Reference Method Data III.B.6.v. Hibbing 2010 Line 2 Reference Method Data III.B.6.w. Hibbing 2010 Lines 1 and 2 PEMS RATA Operating Data III.B.6.x. Hibbing 2011 Lines 1, 2, and 3 NO2 to NOx ratio III.B.7. Hibbing Item 6 Response III.B.7.a. Hibbing NOx and SO2 Potential To Emit III.B.8. Hibbing Item 7 Response III.B.8.a. Hibbing – MPCA Study Entitled: “Evaluation of Minnesota Taconite Wet Scrubbers at Minntac, Keewatub Taconite, Hibbing Taconite, and United Taconite” III.B.8.b. Hibbing – Barr Email Regarding the Cost To Increase Scrubber Efficiency, July 14, 2006 III.B.8.c. Hibbing – EPA CueCost Workbook Version 5.0 III.B.9. Hibbing Item 8 Response III.B.9.a. Hibbing – Agenda and Discussion Points from Meeting Regarding the Technical Feasibility of Low NOx Burners and SCR III.B.9.b. Hibbing – Budget Estimate from Vogt Power III.B.9.c. Hibbing – Email Regarding Discussions with a Low NOx Burner Vendorpage 3 of 10

III.B.10. Hibbing Item 9 Response III.B.10.a. Hibbing – Email from Metso Regarding Feasibility of Overfire Air III.B.11. Hibbing Item 10 Response III.B.11.a. Hibbing – Manufacturer Contact Information III.B.12. Hibbing Item 11 Response III.B.12.a. Hibbing – Combustion Chamber Modification Project, 1/26/06 III.B.12.b. Hibbing – CTG Studies, NOx: Line 3 NOx III.B.12.c. Hibbing – CTG Studies, NOx: Line 3 NOx 25%PA III.B.12.d. Hibbing – CTG Studies, NOx: Line 3 NOx 50%PA III.B.12.e. Hibbing – CTG Studies, NOx: Line 3 NOx 75%PA III.B.12.f. Hibbing – CTG Studies, NOx: Line 3 NOx 100%PA III.B.12.g. Hibbing – CTG Studies, NOx: Lines 1, 2, and 3 NOx Balances III.B.12.h. Hibbing – NOx Alternative Monitoring Method Cover Letter, November 12, 2009 III.B.12.i. Hibbing – NOx Alternative Monitoring Method, November 12, 2009 III.B.12.j. Hibbing – NOx Alternative Monitoring Method Cover Letter, December 9, 2009 III.B.12.k. Hibbing – NOx Alternative Monitoring Method, December 9, 2009 III.B.12.l. Hibbing – Alternative Method Proposal, March 31, 2008 III.B.12.m. Hibbing – Line 1 Alternative Method Proposal III.B.12.n. Hibbing – Line 2 Alternative Method Proposal III.B.12.o. Hibbing – Line 3 Alternative Method Proposal III.B.12.p. Hibbing – NOx Formation Project: Baseline Graphs III.B.12.q. Hibbing – NOx Formation Project: Analyze Phase III.B.12.r. Hibbing – NOx Formation Project: Control Phase III.B.12.s. Hibbing – NOx Formation Project: Improve Phase III.B.12.t. Hibbing – NOx Formation Project: Define Presentation – NOx Formation III.B.12.u. Hibbing – NOx Formation Project: Measure Presentation Template III.B.12.v. Hibbing – PEMS Discussion Summary, June 4, 2010 III.B.12.w. Hibbing – Testing PEMS Using 24-Hour Average Predictors III.B.12.x. Hibbing – NOx PEMS Write-up, 2012 III.B.12.y. Hibbing – Minitab File III.B.12.z. Hibbing – Barr BART NOx Emission Reduction Analysis, December 10, 2007 III.B.13. Hibbing Item 13 Response III.B.13.a. Hibbing – Barr Email, Discussion of Process Optimization, July 12, 2006 III.B.13.b. Hibbing Bart Analysis III.B.14. Hibbing Item 15 Response III.B.14.a. Hibbing – Formation of NOx in Iron Oxide Pelletizing Furnaces III.B.14.b. Hibbing – NOx Reduction in Industrial Heat Processing III.B.14.c. Hibbing – Measure Presentation Template III.B.14.d. Hibbing – NOx Emission Reduction During Pellet Induration by Fuel-Addition to the Green-Pellet III.B.14.e. Hibbing – Barr Email, Regarding Kiln NOx Emissions, May 12, 2006 III.B.15. Hibbing Item 7-9 Supporting Documents III.B.15.a. Hibbing – Guidance Documents: 2003 BART and Taconite Report from Barr III.B.15.b. Hibbing – Guidance Documents: Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations, 70 FR

39164 III.B.15.c. Hibbing – Guidance Documents: Northshore Furnace 5 Reactivation Project and BACT Analysis III.B.15.d. Hibbing – Guidance Documents: Email from Barr to MPCA Regarding NOx and SOx Control Technologies, May 9, 2006 III.B.15.e. Hibbing – Guidance Documents: MPCA's 2006 Guidelines for Facilities Conducting a BART Analysis

III.C. Northshore III.C.1. Northshore 114 Cover Letter and Summary of Response, May 4, 2012 III.C.2. Northshore Item 1 Response III.C.2.a. Northshore Process Description III.C.2.b. Northshore Process Diagrampage 4 of 10

III.C.2.c. Northshore Process Pictures III.C.2.d. Northshore Furnace Diagram III.C.2.e. Northshore Process Descripton, Furnaces 5 and 6 III.C.2.f. Northshore Process Description, Furnaces 11 and 12 III.C.3. Northshore Item 2 Response III.C.3.a. Northshore Operating Data III.C.4. Northshore Item 3 Response III.C.4.a. Northshore Natural Gas Usage III.C.5. Northshore Item 5 Response III.C.5.a. Northshore 2000 NOx Stack Test, SV 262, SV 113, SV 114 III.C.5.b. Northshore 2005 NOx Stack Test, SV 104, SV 261 III.C.5.c. Northshore 2006 NOx Stack Test, SV 112, SV 114 III.C.5.d. Northshore 2007 NOx Stack Test, July, SV 104 III.C.5.e. Northshore 2007 NOx Stack Test, March, SV104 III.C.5.f. Northshore 2008 SO2 Stack Test, SV 266 III.C.5.g. Northshore 2009 NOx Stack Test, EU 104, EU114 III.C.5.h. Northshore 2010 NOx Stack Test, EU 104, EU 114 III.C.5.i. Northshore 2011 NOx Stack Test, EU 104, EU 114 III.C.6. Northshore Item 6 Response

III.C.6.a. Northshore NOx and SO2 Potential to Emit Calculations III.C.7. Northshore Item 7 Response III.C.7.a. Northshore – Furnace 5 Restart BACT Analysis III.C.7.b. Northshore – Barr SO2 Scrubber Cost Adjustment, January 10, 2007 III.C.7.c. Northshore – Furnace BART Report III.C.7.d. Northshore – Furnace BART Report: Appendix A - Control Costs III.C.7.e. Northshore – Furnace BART Report: Appendix A - Process Boiler Control Cost III.C.7.f. Northshore – Furnace BART Report: Appendix B – Taconite BART Response to Comment III.C.7.g. Northshore – Furnace BART Report: Appendix B Taconite BART Protocol Revised, May 16, 2006 III.C.7.h. Northshore – Furnace BART Report: Appendix B BART Modeling Domain III.C.7.i. Northshore – Furnace BART Report: Appendix C Modeling Report III.C.7.j. Northshore – Furnace BART Report: Appendix C Northshore Site Plan III.C.7.k. Northshore – Furnace BART Report: Appendix D List of Control Technologies, NOx III.C.7.l. Northshore – Furnace BART Report: Appendix D List of Control Technologies, SO2 III.C.7.m. Northshore – Furnace BART Report: Appendix E Table of Costs Per Ton III.C.7.n. Northshore – Furnace BART Report: Appendix F Process Boilers List of NOx Control Technologies III.C.7.o. Northshore – Furnace BART Report: Appendix F Process Boilers List of SO2 Control Technologies III.C.8. Northshore Item 7-9 Supporting Documents III.C.8.a. Northshore – Guidance Documents: MPCA/Barr Engineering Report Entitlted “Potential Impacts of the Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry In Minnesota” III.C.8.b. Northshore – Guidance Documents: Email from Barr to MPCA Regarding NOx and SOx Control Technologies, May 9, 2006 III.C.8.c. Northshore – Guidance Documents: MPCA's 2006 Guidelines for Facilities Conducting a BART Analysis III.C.8.d. Northshore – Guidance Documents: Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations, 70 FR

39164 III.C.8.e. Northshore – Furnace 5 Restart BACT Analysis III.C.9. Northshore Item 8 Response III.C.9.a. Northshore – Barr Low NOx Burner Vendor Discussion, August 2, 2006 III.C.9.b. Northshore – Osmndson BART Comments, August 30, 2006 III.C.9.c. Northshore – Agenda and Discussion Points from Meeting Regarding the Technical Feasibility of Low NOx Burners and SCR III.C.9.d. Northshore – Vogt Vendor Budget Estimate (Redacted) III.C.9.e. Northshore – – MPCA/Barr Engineering Report Entitlted “Potential Impacts of the Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry In Minnesota” III.C.10. Northshore Item 9 Responsepage 5 of 10

III.C.10.a. Northshore – Email from Metso Regarding Feasibility of Overfire Air III.C.10.b. Northshore Furnace 5 Restart BACT Analysis III.C.11. Northshore Item 10 Response

III.C.11.a. Northshore – Manufacturer Contact Information III.C.12. Northshore Item 11 Response III.C.12.a. Northshore – NOx Generation in Northshore Mining Furnaces III.C.13. Northshore Item 12 Response

III.C.13.a. Northshore CEMS Data III.C.14. Northshore Item 13 Response III.C.14.a. Northshore – Barr Email, Discussion of Process Optimization, July 12, 2006 III.C.14.b. Northshore Furnace BART Report III.C.15. Northshore Item 14 Response

III.C.15.a. Northshore NOx CEMS Emissions Data III.C.16. Northshore Item 15 Response III.C.16.a. Northshore – Barr Email, Regarding Kiln NOx Emissions, May 12, 2006 III.C.16.b. Northshore – Formation of NOx in Iron Oxide Pelletizing Furnaces III.C.16.c. Northshore NOx Generation in Northshore Mining Furnaces

III.D. United Taconite III.D. United Taconite1. United Taconite 114 Cover Letter, May 4, 2012 III.D. United Taconite2. United Taconite Summary of 114 Response III.D. United Taconite3. United Taconite Item 1 Response III.D. United Taconite3.a. United Taconite Process Diagram: Mine, External III.D. United Taconite3.b. United Taconite Process Diagram: Crusher, External III.D. United Taconite3.c. United Taconite Process Diagram: Concetco III.D. United Taconite3.d. United Taconite Process Diagram: Concexco III.D. United Taconite3.e. United Taconite Process Diagram: Filter, External III.D. United Taconite3.f. United Taconite Process Diagram: Balling, External III.D. United Taconite3.g. United Taconite Process Diagram: Kiln, External III.D. United Taconite3.h. United Taconite Process Diagram: Loadout III.D. United Taconite3.i. United Taconite Pages from 13700011-001 Air Permit-Mine III.D. United Taconite3.j. United Taconite Pages from 13700113-005 Air Permit - Plant III.D. United Taconite4. United Taconite Item 2 Response

III.D. United Taconite4.a. United Taconite – Allis Chalmers Flowsheet Information All Plants III.D. United Taconite4.b. United Taconite Operating Data III.D. United Taconite4.c. United Taconite Process Diagram Temperature Explanation III.D. United Taconite4.d. United Taconite – Summary Table, Furnace Line Specifications III.D. United Taconite4.e. United Taconite – Pages from Supplemental Regional Haze SIP - March 2012 Citizen's Board III.D. United Taconite4.f. United Taconite Line 1 Burner Manufacturing Specifications – C1110-OM Manual Line 1 Burner Specs 2011 III.D. United Taconite4.g. United Taconite Line 1 Burner Manufacturing Specifications – C1110-A-PD-01-REV1 III.D. United Taconite4.h. United Taconite Line 1 Burner Manufacturing Specifications, Pre-August 2011 Burner – C0882-OM Manual Line 1 Burner Specifications III.D. United Taconite4.i. United Taconite Line 1 Burner Manufacturing Specifications, Pre-August 2011 Burner III.D. United Taconite4.j. United Taconite Line 2 Burner Manufacturing Specifications – III.D. United Taconite5. United Taconite Item 3 Response III.D. United Taconite5.a. United Taconite Natural Gas Usage III.D. United Taconite6. United Taconite Item 4 Response III.D. United Taconite6.a. United Taconite Weekly Coal Analysis III.D. United Taconite6.b. United Taconite – Pages from 13700113-005 Air Permit - Fuel Sampling III.D. United Taconite7. United Taconite Item 5 Response III.D. United Taconite7.a. United Taconite – Pages from 13700113-005 Air Permit - Stack Test Process Rates III.D. United Taconite7.b. United Taconite – Summary of Stack Test Reports III.D. United Taconite7.c. United Taconite – Stack Test, June 2004 Part 1page 6 of 10

III.D. United Taconite7.d. United Taconite – Stack Test, June 2004 Part 2 III.D. United Taconite7.e. United Taconite – Stack Test, December 2004 - January 2005 III.D. United Taconite7.f. United Taconite – Stack Test, May 2005 Part 1 III.D. United Taconite7.g. United Taconite – Stack Test, May 2005 Part 2 III.D. United Taconite7.h. United Taconite – Stack Test, April-May 2006 III.D. United Taconite7.i. United Taconite – Stack Test, December 2009 III.D. United Taconite7.j. United Taconite – Line 2 Stack Test, April 2011 III.D. United Taconite7.k. United Taconite – Stack Test, December 2011 III.D. United Taconite8. United Taconite Item 6 Response

III.D. United Taconite8.a. United Taconite NOx and SO2 Potential to Emit III.D. United Taconite9. United Taconite Item 7 Response

III.D. United Taconite9.a. United Taconite – EPA CueCost Workbook III.D. United Taconite9.b. United Taconite – MPCA Study Entitled “Evaluation of Minnesota Taconite Wet Scrubbers at Minntac, Keewatub Taconite, Hibbing Taconite, and United Taconite” III.D. United Taconite9.c. United Taconite Revised BART Analysis Submittal, Line 2 SO2 Control III.D. United Taconite9.d. United Taconite – Barr Email Regarding the Cost To Increase Scrubber Efficiency, July 14, 2006 III.D. United Taconite9.e. United Taconite Dry ESP Feasibility Study, January 30, 2009 III.D. United Taconite9.f. United Taconite – Email: Jason Aagenes to Mary Jean Fenske with Attachment, January 31, 2007 III.D. United Taconite9.g. United Taconite – Email: Mary Jean Fenske to Jason Aagenes with Attachment, February 2, 2007 III.D. United Taconite9.h. United Taconite – Email: Beth Havlik to Jason Aagenes, May 29, 2007 III.D. United Taconite9.i. United Taconite – Email: Beth Havlik to Jason Aagenes with Attachment, May 30, 2007 III.D. United Taconite9.j. United Taconite – Email: Mary Jean Fenske to Jason Aagenes with Attachment, June 26, 2007 III.D. United Taconite9.k. United Taconite – Email: Beth Havlik to Jason Aagenes, June 27, 2007 III.D. United Taconite9.l. United Taconite – Email: Jason Aagenes to George Pruchnofski , June 27, 2007 III.D. United Taconite9.m. United Taconite – Email: Beth Havlik to Jason Aagenes with Attachment, July 2, 2007 III.D. United Taconite9.n. United Taconite – Email: George Pruchnofski to Jason Aagenes, July 5, 2007 III.D. United Taconite9.o. United Taconite – Email: Anne Jackson to Jason Aagenes , July 13, 2007 III.D. United Taconite9.p. United Taconite – Email: Beth Havlik to Jason Aagenes, July 24, 2007 III.D. United Taconite9.q. United Taconite – Email: George Pruchnofski to Jason Aagenes, July 24, 2007 III.D. United Taconite9.r. United Taconite – Email: Beth Havlik to Jason Aagenes, July 25, 2007 III.D. United Taconite9.s. United Taconite – Email: Beth Havlik to Jason Aagenes, April 3, 2009 III.D. United Taconite9.t. United Taconite Mass Balance Studies, July 17, 2001 III.D. United Taconite9.u. United Taconite Mass Balance Studies, August 6, 2001 III.D. United Taconite9.v. United Taconite Mass Balance Studies, July 29, 2004 III.D. United Taconite9.w. United Taconite Mass Balance Studies, Table 5, July 26, 2006 III.D. United Taconite9.x. United Taconite Mass Balance Studies, Table 6 July 26, 2006 III.D. United Taconite9.y. United Taconite Mass Balance Studies, January 28, 2010 III.D. United Taconite10. United Taconite Item 8 Response III.D. United Taconite10.a. United Taconite – Agenda and Discussion Points from Meeting Regarding the Technical Feasibility of Low NOx Burners and SCR III.D. United Taconite10.b. United Taconite – Vogt Vendor Budget Estimate (Redacted) III.D. United Taconite10.c. United Taconite – Email: Jason Aagenes to Mary Jean Fenske with Attachment, January 31, 2007 III.D. United Taconite11. United Taconite Item 9 Response III.D. United Taconite11.a. United Taconite – Email from Metso Regarding Feasibility of Overfire Air III.D. United Taconite12. United Taconite Item 10 Response

III.D. United Taconite12.a. United Taconite – Manufacturer Contact Information III.D. United Taconite13. United Taconite Item 11 Response III.D. United Taconite13.a. United Taconite – Email Douglas Hawkins to Jason Aagenes with Attachment, July 5, 2007

III.D. United Taconite13.b. United Taconite – Line 1 Burner Observations 2012 NOx Tests III.D. United Taconite14. United Taconite Item 12 Response

III.D. United Taconite14.a. United Taconite CEMS Data III.D. United Taconite14.b. United Taconite CEMS Data Calculation Explanationpage 7 of 10

III.D. United Taconite15. United Taconite Item 13 Response III.D. United Taconite15.a. United Taconite – Barr Email, Discussion of Process Optimization, July 12, 2006 III.D. United Taconite15.b. United Taconite BART Analysis III.D. United Taconite16. United Taconite Item 14 Response III.D. United Taconite16.a. United Taconite Daily NOx Emissions III.D. United Taconite17. United Taconite Item 15 Response III.D. United Taconite17.a. United Taconite – Barr Email, Regarding Kiln NOx Emissions, May 12, 2006 III.D. United Taconite17.b. United Taconite – Report: Thermal NOx Formation in a Taconite Pellet Rotary Kiln III.D. United Taconite17.c. United Taconite – Formation of NOx in Iron Oxide Pelletizing Furnaces III.D. United Taconite17.d. United Taconite – Model and Simulation of Heat Transfer, Magentite Oxidation and NOx Formation in a Grate-Kiln Taconite Pellet Induration III.D. United Taconite18. United Taconite Item 7-9 Supporting Documentation III.D. United Taconite18.a. United Taconite – Guidance Documents: Email from Barr to MPCA Regarding NOx and SOx Control Technologies, May 9, 2006 III.D. United Taconite18.b. United Taconite – Northshore Furnace 5 Restart BACT Analysis III.D. United Taconite18.c. United Taconite – Guidance Documents: MPCA's 2006 Guidelines for Facilities Conducting a BART Analysis III.D. United Taconite18.d. United Taconite – Guidance Documents: MPCA/Barr Engineering Report Entitlted “Potential Impacts of the III.D. United Taconite18.e. United Taconite – Guidance Documents: Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations, 70 FR 39164 III.E. U.S. Steel Keetac III.E. U.S. Steel Keetac1. U.S. Steel Keetac 114 Cover Letter, April 24, 2012 III.E. U.S. Steel Keetac2. U.S. Steel Keetac Item 1 Response III.E. U.S. Steel Keetac2.a. U.S. Steel Keetac Process Response III.E. U.S. Steel Keetac2.b. U.S. Steel Keetac Agglomerator Flowsheet

III.E. U.S. Steel Keetac2.c. U.S. Steel Keetac Concentrator Flowsheet

III.E. U.S. Steel Keetac2.d. U.S. Steel Keetac Airflows III.E. U.S. Steel Keetac3. U.S. Steel Keetac Item 2 Response III.E. U.S. Steel Keetac3.a. U.S. Steel Keetac Operating Parameters III.E. U.S. Steel Keetac4. U.S. Steel Keetac Item 3 Response III.E. U.S. Steel Keetac4.a. U.S. Steel Keetac Natural Gas Usage Cover Sheet III.E. U.S. Steel Keetac4.b. U.S. Steel Keetac Natural Gas Usage III.E. U.S. Steel Keetac5. U.S. Steel Keetac Item 4 Response

III.E. U.S. Steel Keetac5.a. U.S. Steel Keetac Coal Sulfur Content III.E. U.S. Steel Keetac6. U.S. Steel Keetac Item 5 Response III.E. U.S. Steel Keetac6.a. U.S. Steel Keetac Stack Test Response Cover Sheet III.E. U.S. Steel Keetac6.b. U.S. Steel Keetac Stack Test, 2006 III.E. U.S. Steel Keetac6.c. U.S. Steel Keetac Stack Test, 2005 III.E. U.S. Steel Keetac7. U.S. Steel Keetac Item 6 Response III.E. U.S. Steel Keetac7.a. U.S. Steel Keetac NOx and SO2 Potential to Emit Response Cover Sheet

III.E. U.S. Steel Keetac7.b. U.S. Steel Keetac NOx and SO2 Potential to Emit III.E. U.S. Steel Keetac8. U.S. Steel Keetac Item 7 Response

III.E. U.S. Steel Keetac8.a. U.S. Steel Keetac Wet Scrubber Information III.E. U.S. Steel Keetac9. U.S. Steel Keetac Item 8 Response III.E. U.S. Steel Keetac9.a. U.S. Steel Keetac NOx Reduction Technology Evaluation Cover Sheet III.E. U.S. Steel Keetac9.b. U.S. Steel Keetac NOx Reduction Technology Evaluation for Expansion Line III.E. U.S. Steel Keetac10. U.S. Steel Keetac Item 9 Response III.E. U.S. Steel Keetac10.a. U.S. Steel Keetac Overfire Air Response III.E. U.S. Steel Keetac11. U.S. Steel Keetac Item 10 Response III.E. U.S. Steel Keetac11.a. U.S. Steel Keetac Manufacturer Contact Information Response III.E. U.S. Steel Keetac12. U.S. Steel Keetac Item 11 Response III.E. U.S. Steel Keetac12.a. U.S. Steel Keetac NOx Waste Gas Study Response Cover Sheet III.E. U.S. Steel Keetac12.b. U.S. Steel Keetac CEMS NOx Data Analysispage 8 of 10

III.E. U.S. Steel Keetac12.c. U.S. Steel Keetac – Excerpts from Class I Report, December 2010 III.E. U.S. Steel Keetac13. U.S. Steel Keetac Item 12 Response III.E. U.S. Steel Keetac13.a. U.S. Steel Keetac NOx and SO2 CEMS Data Response Cover Sheet III.E. U.S. Steel Keetac13.b. U.S. Steel Keetac Hourly NOx and SO2 Data III.E. U.S. Steel Keetac14. U.S. Steel Keetac Item 13 Response III.E. U.S. Steel Keetac14.a. U.S. Steel Keetac Process Optimization Response Cover Sheet III.E. U.S. Steel Keetac15. U.S. Steel Keetac Item 14 Response III.E. U.S. Steel Keetac15.a. U.S. Steel Keetac NOx Emissions Data Response Cover Sheet III.E. U.S. Steel Keetac15.b. U.S. Steel Keetac NOx CEMS Daily and 30-Day Emissions Data III.E. U.S. Steel Keetac16. U.S. Steel Keetac Item 15 Response III.E. U.S. Steel Keetac16.a. U.S. Steel Keetac NOx Emissions Sources Response Cover Sheet III.E. U.S. Steel Keetac17. U.S. Steel Keetac Item 16 Response III.E. U.S. Steel Keetac17.a. U.S. Steel Keetac Persons Consulted Response

III.F. U.S. Steel Minntac III.F. U.S. Steel Minntac1. U.S. Steel Minntac 114 Cover Letter, April 24, 2012 III.F. U.S. Steel Minntac2. U.S. Steel Minntac Item 1 Response III.F. U.S. Steel Minntac2.a. U.S. Steel Minntac Process Flow Response III.F. U.S. Steel Minntac2.b. U.S. Steel Minntac Agglomerator Overview III.F. U.S. Steel Minntac2.c. U.S. Steel Minntac Agglomerator Process Description III.F. U.S. Steel Minntac3. U.S. Steel Minntac Item 2 Response III.F. U.S. Steel Minntac3.a. U.S. Steel Minntac Operating Parameters Response III.F. U.S. Steel Minntac4. U.S. Steel Minntac Item 3 Response III.F. U.S. Steel Minntac4.a. U.S. Steel Minntac Natural Gas Usage III.F. U.S. Steel Minntac5. U.S. Steel Minntac Item 4 Response

III.F. U.S. Steel Minntac5.a. U.S. Steel Minntac Coal Sulfur Content III.F. U.S. Steel Minntac6. U.S. Steel Minntac Item 5 Response III.F. U.S. Steel Minntac6.a. U.S. Steel Minntac Stack Test Response Cover Sheet III.F. U.S. Steel Minntac6.b. U.S. Steel Minntac Miscellaneous Stack Test History Through 2011 III.F. U.S. Steel Minntac6.c. U.S. Steel Minntac Stack Tests, June 2005 #1 III.F. U.S. Steel Minntac6.d. U.S. Steel Minntac Tests, June 2005 #2 III.F. U.S. Steel Minntac6.e. U.S. Steel Minntac Tests, July 2005 #1 III.F. U.S. Steel Minntac6.f. U.S. Steel Minntac Tests, July 2005 #2 III.F. U.S. Steel Minntac6.g. U.S. Steel Minntac Tests, August 2005 #1 III.F. U.S. Steel Minntac6.h. U.S. Steel Minntac Tests, August 2005 #2 III.F. U.S. Steel Minntac6.i. U.S. Steel Minntac Step 1 Agglomerator Stack Tests III.F. U.S. Steel Minntac6.j. U.S. Steel Minntac Step 2 Agglomerator Stack Tests III.F. U.S. Steel Minntac6.k. U.S. Steel Minntac Step 3 Agglomerator Stack Tests

III.F. U.S. Steel Minntac6.l. U.S. Steel Minntac Cooler Vent Stack Tests III.F. U.S. Steel Minntac7. U.S. Steel Minntac Item 6 Response III.F. U.S. Steel Minntac7.a. U.S. Steel Minntac NOx and SO2 Potential to Emit Response Cover Sheet

III.F. U.S. Steel Minntac7.b. U.S. Steel Minntac NOx and SO2 Potential to Emit III.F. U.S. Steel Minntac8. U.S. Steel Minntac Item 7 Response

III.F. U.S. Steel Minntac8.a. U.S. Steel Minntac Wet Scrubber Information Cover Sheet III.F. U.S. Steel Minntac8.b. U.S. Steel Minntac Sulfur Balance, 1994 III.F. U.S. Steel Minntac8.c. U.S. Steel Minntac Wet Scrubber Report III.F. U.S. Steel Minntac9. U.S. Steel Minntac Item 8 Response III.F. U.S. Steel Minntac9.a. U.S. Steel Minntac NOx Reduction Technology Response Cover Sheet III.F. U.S. Steel Minntac9.b. U.S. Steel Minntac 8-14-09 Pilot TestingLetter III.F. U.S. Steel Minntac9.c. U.S. Steel Minntac 1-11-10 NOx Pilot Testing Letter to MPCA III.F. U.S. Steel Minntac9.d. U.S. Steel Minntac 1-12-10 MPCA to US Steel Letter Regarding NOx Reduction Testing III.F. U.S. Steel Minntac9.e. U.S. Steel Minntac 2-15-10 Minntac NOx Reduction Progress Update III.F. U.S. Steel Minntac9.f. U.S. Steel Minntac 3-24-10 MPCA to Minntac Response to February 2010 Submittalspage 9 of 10

III.F. U.S. Steel Minntac9.g. U.S. Steel Minntac 9-23-10 Minntac NOx Pilot Testing Letter III.F. U.S. Steel Minntac9.h. U.S. Steel Minntac 1-18-11 MPCA Letter to US Steel Regarding Low NOx Burner Testing

III.F. U.S. Steel Minntac9.i. U.S. Steel Minntac 1-28-11 MPCA Letter to USS III.F. U.S. Steel Minntac9.j. U.S. Steel Minntac 6-4-2990 Aker Solutions Letter to USS III.F. U.S. Steel Minntac9.k. U.S. Steel Minntac Final PR332002-01 US Steel Minntac - NOx Reduction Technology Report Rev 0 III.F. U.S. Steel Minntac9.l. U.S. Steel Minntac Line 6 Burner Final Report, December 1, 2011 III.F. U.S. Steel Minntac9.m. U.S. Steel Minntac Line 7 Burner Final Report, May 13, 2011 III.F. U.S. Steel Minntac9.n. U.S. Steel Minntac Line 7 Pilot Testing Update, October 22, 2010 III.F. U.S. Steel Minntac9.o. U.S. Steel Minntac Low NOx Main Burner Approval III.F. U.S. Steel Minntac9.p. U.S. Steel Minntac Mitsubishi Decline to Bid III.F. U.S. Steel Minntac9.q. U.S. Steel Minntac NOx Technology Report Appendix III.F. U.S. Steel Minntac9.r. U.S. Steel Minntac Final SNCR Report, October 27, 2009 III.F. U.S. Steel Minntac9.s. U.S. Steel Minntac Response to MPCA Letter Regarding SCR and Low Temperature Oxidation III.F. U.S. Steel Minntac10. U.S. Steel Minntac Item 9 Response III.F. U.S. Steel Minntac10.a. U.S. Steel Minntac Overfire Air Response III.F. U.S. Steel Minntac11. U.S. Steel Minntac Item 10 Response III.F. U.S. Steel Minntac11.a. U.S. Steel Minntac Manufacturer Contact Information Response III.F. U.S. Steel Minntac12. U.S. Steel Minntac Item 11 Response III.F. U.S. Steel Minntac12.a. U.S. Steel Minntac Waste Gas Study Response Cover Sheet III.F. U.S. Steel Minntac12.b. U.S. Steel Minntac PR-332571 Rev0 Final Project Report III.F. U.S. Steel Minntac12.c. U.S. Steel Minntac PR-332571 Rev1 Final Project Report-Variant Cases III.F. U.S. Steel Minntac13. U.S. Steel Minntac Item 12 Response III.F. U.S. Steel Minntac13.a. U.S. Steel Minntac NOx and SO2 CEMS Data Response Cover Sheet III.F. U.S. Steel Minntac13.b. U.S. Steel Minntac CEMS Data (2005-Current) III.F. U.S. Steel Minntac13.c. U.S. Steel Minntac Furnace Temp (2009-Current) III.F. U.S. Steel Minntac14. U.S. Steel Minntac Item 13 Response III.F. U.S. Steel Minntac14.a. U.S. Steel Minntac Optimization Response Cover Sheet III.F. U.S. Steel Minntac15. U.S. Steel Minntac Item 14 Response III.F. U.S. Steel Minntac15.a. U.S. Steel Minntac NOx Emissions Data Response Cover Sheet

III.F. U.S. Steel Minntac15.b. U.S. Steel Minntac NOx Emissions Data III.F. U.S. Steel Minntac16. U.S. Steel Minntac Item 15 Response III.F. U.S. Steel Minntac16.a. U.S. Steel Minntac NOx Emissions Sources Response Cover Sheet III.F. U.S. Steel Minntac16.b. U.S. Steel Minntac NOx Summary (Coen Report) III.F. U.S. Steel Minntac17. U.S. Steel Minntac Item 16 Response III.F. U.S. Steel Minntac17.a. U.S. Steel Minntac Persons Consulted Response III.F. U.S. Steel Minntac18. U.S. Steel Minntac Item 17 Response III.F. U.S. Steel Minntac18.a. U.S. Steel Minntac Cost Information Response III.F. U.S. Steel Minntac18.b. U.S. Steel Minntac Line 6 Low NOx Main Burner Cost Evaluation , April 4, 2012 III.F. U.S. Steel Minntac19. U.S. Steel Minntac Item 18 Response III.F. U.S. Steel Minntac19.a. U.S. Steel Minntac Response Regarding Improving the Performance of Line 6 Low NOX Main Burner III.F. U.S. Steel Minntac19.b. U.S. Steel Minntac Biomass Testing Report, April 11, 2012

III.G. Barr

III.G.1. Barr – Cover Letter and Table of Contents III.G.2. Barr – Response 1 Through 5 III.G.3. Barr – Attachment A Cost Threshold Response 1 III.G.4. Barr – Attachment B Keetac Cost Response 2 III.G.5. Barr – Attachment C Minntac Cost Response 2 III.G.6. Barr – Attachment D Northshore Cost Response 2 III.G.7. Barr – Attachment E Hibbtac Cost Response 2 III.G.8. Barr – Attachment F United Taconite Cost Response 2 III.G.9. Barr – Attachment G ArcelorMittal Cost Response 2 III.G.10. Barr – MSI BACT Report Resposne 5page 10 of 10

III.G.11. Barr – Essar BACT Response 5 III.G.12. Barr – Northshore Furnace 5 Restart Vol I BACT Response 5 III.G.13. Barr – Keetac NOx Technology Evaluation Response 5 IV. NOx BART Analysis – Low NOx Burner Technical Support

IV.A. FIVES Fact Sheets IV.B. U.S. Steel Minntac NOx Reduction Technology Report, January 30, 2009 IV.C. Essar Burner Test 21a, July 28, 2011 IV.D. ESML-MPCA Quarter-Scale Low NOx Burner Test Report , September 26, 2011 IV.E. Summary Report for U.S. Steel Minntac NOx Kilns 6 and 7 IV.F. U.S. Steel Minntac Line 6 Low NOx Burner Final Report, December 1, 2011

IV.G. Essar and Barr SME 2012 Presentaion IV.H. FIVES SME 2012 Presentation, April 17, 2012

IV.I. Minntac Line 6 NOx Emissions V. SO2 BART Analysis

V.A. Basis for SO2 Limits – No Additional Control

V.A.1. ArcelorMittal Notes V.A.2. Hibbing Notes

V.A.3. Northshore

V.A.3.a. Northshore Notes

V.A.3.b. Northshore Production Rates V.A.4. U.S. Steel Keetac(VA4-Keetac_SO2)

V.A.5. U.S. Steel Minntac

V.A.5.a. U.S. Steel Minntac Notes V.A.5.b. U.S. Steel Minntac Line 3 2010-Current CEMS Data (VA5b-Minntac CEMS Data L3 V.A.5.c. U.S. Steel Minntac Line 4 2010-Current CEMS Data (VA5c-Minntac CEMS Data L4 V.A.5.d. U.S. Steel Minntac Line 5 2010-Current CEMS Data (VA5d-Minntac CEMS Data L5 V.A.5.e. U.S. Steel Minntac Line 6 2010-Current CEMS Data (VA5e-Minntac CEMS Data L6 V.A.5.f. U.S. Steel Minntac Line 7 2010-Current CEMS Data (VA5f-Minntac CEMS Data L7 V.B. Flue-Gas Desulfurization (FGD) Feasibility V.B.1. Email from Lars Hansen to Sara Cervak Regarding Installation Times for Dry Circulating Fluid Bed Scrubbers, July 13, 2012 V.B.2. Technical Support for SO2 Control Technology

V.B.2.a. Essar

V.B.2.b. Keetac V.B.2.c. Dry Controls Permit Application – Minntac V.B.2.d. SO2 Emissions Summary for Tilden and UTAC V.B.2.e. Small Unit Dry FGDs

V.B.2.f. BART DJ3 December 2007 V.B.2.g. GBB BART Eng Analysis Attachment B V.B.3. Excerpts from ESSAR SO2 BACT

V.C. FGD Cost Effectiveness and Limits V.C.1. Email from Chrissy Bartovich to Steven Rosenthal Regarding Capital Equipment Costs, July 2, 2012 V.C.2. Email from Chrissy Bartovich to Steven Rosenthal Regarding Line 6 Questions, July 19, 2012 V.C.3. Information on Dry FGD Costs (Includes Email from Kevin Tran to Steven Rosenthal) V.C.4. United Taconite Line 1 and Line 2 SO2 Cost-Effectiveness Analysis, August 1, 2012 V.C.4.a. Revised Corrected Updated UTAC Line 1 GSA@90% V.C.4.b. Revised Corrected Updated UTAC Line 1 GSA@95% V.C.4.c. Revised Corrected Updated UTAC Line 2 GSA@90% V.C.4.d. Revised Corrected Updated UTAC Line 2 GSA@95% V.C.5. Email from Candice Maxwell to Steven Rosenthal Regarding United Taconite Line 1 and 2 Scrubbers, June 18, 2012

V.C.6. Cost-effectiveness Metrics

V.C.7. EPA Air Pollution Control Cost Manual VI. Discussion of Testing, Monitoring, Recordkeeping and Reporting Requirements