VIA OVERNIGHT DELIVERY United States Steel Corporation l_aw Department 600 ()rant Street Pittsburqh, PA 152192800 Tel: 412A33.2919 Fax:412.433.2fl64 E-mail: ·dwhacker@uss.com April 24, 2012

Attn: Compliance Tracker, AE-17J Air Enforcement and Compliance Assurance Branch U.S
. Environmental Protection Agency- Region 5 77 West Jackson Boulevard Chicago, IL 60604 Re: United States Steel Corporation- Minntac Response to Section 114 Information Collection Request Dear U. S. EPA Region V Representative: David W. Hacker General Attorney-Environmental

On or about April 5, 2012, United States Steel Corporation (U. S. Steel) received a Clean Air Act Section 114 Request for Information regarding its Minntac facility. In response to that request, U. S. Steel is providing the requested information, as explained below and in the attached disc. Since receiving the Request, U. S
. Steel and U. S. EPA have had a teleconference and exchanged telephone calls. On April 9th, Chrissy Bartovich of U. S
. Steel had a call with Patrick Miller and Bill Wagner from U. S
. EPA During that call, among other things, U. S. EPA agreed to have the start date be concurrent for both the Keetac and Minntac facilities so although the Request to Minntac was received on or about April 5th,the time accural for the response started on April 9th; i.e., responses for both facilities, if submitted on or before April 24th,would be considerd timely. In addition and most significantly, U. S
. EPA representatives visited U. S. Steel's Minntacfacility on April 18, 2012 to review the facility's compliance with the taconite MACT standards as well as the application of BART at the facility. During the visit, U. S
. Steel provided an overview ofthe Minntac operations, and addressed U. S. EPA's questions. many relating to burners. Afterthe overview was discussed, U. S. EPA toured the Step 3 Agglomerator, including the process equipment, low NOx burner and ancillary equipment. In sum, it was a comprehensive tour discussing how the facility operates. During the tour, U. S
. EPA took 70 photographs. U. S
. Steel respectfully requests that all such photographs taken during the tour be treated as Confidential Business Information (CBI), as they include proprietary information and provide insight to Minntac operations that is not publicly available. U. S
. Steel takes reasonable measures to protect the confidentiality of such pictures and continues to do so, and any such photographs of equipment and processes are proprietary in nature and such photographs are not and have not been reasonably obtainable by legitimate means without U. S
. Steel's consent.Attn: Compliance Tracker, AE-17

### J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 2The responses provided herein and in the attached discs are consistent with our discussions with U. S. EPA and the instructions provided in the Section 114 inquiry. For ease of review, U. S. Steel has provided the response to each request in a separate subfolder in the attached disc. In the disc, the inquiries as numbered and provided in the request along with U. S. Steel's responses are provided along with attachments that are responsive to the corresponding request. Please note that two discs with responsive information are being provided. The first disc contains information that is not considered CBI, while the second disc contains all responsive information that is deemed CBI. In particular,the responses to Items 1 and 11 ofthe Request sent to Minntac include such CBI. While U. S
. Steel appreciates the Agency's consideration of accepting responses regarding a more limited scope and/or oftime period, U. S
. Steel believes that the Requests are unduly burdensome and overly broad, especially to the time frame to which the Requests pertain and the time frame or schedule in which responses were requested . U. S. Steel specifically objects to any definition or Request that can be interpreted to impose on U. S
. Steel an obligation to collect or create information greater than that imposed by §114 ofthe Clean AirAct. Furthermore, U. S
. Steel questions the relevance and probative value of some ofthese Requests, and by providing a response, U. S
. Steel does not concede to the relevance or materiality ofthe information sought by any request or subject matter to which they refer, nor does U. S. Steel waive any such objections. Please note that the responses provided herein or attached shall not constitute any admission of liability on the part of U. S. Steel for any alleged violations. Subjectto the conditions noted above, enclosed herein, please find our responses to the Request received by Minntac on or about April 5, 2012. 1 . U.S. EPA REQUEST: Provide process flow diagrams for both the taconite iron ore mining and the taconite pellet manufacturing processes. Include in the description, at a minimum, information on the following : mining operations, ore transfer and storage, course ore crushing, fine ore crushing, ore classification screens, ore storage bins, grinding rod/ball mills, separation,thickeners, balling drums/pellet formation , indurating furnace, pellet cooling and storage, and the process boilers. Include a detailed narrative process description and photographs to explain the indurating furnace process (separately for each furnace)
. For each photograph, provide a coded diagram/map to clearly identify the location ofthe image in the photograph. Photographs must correspond to each of the process stages described. U. S. STEEL RESPONSE: Please see the attached two discs for information that is responsive to this request. The first disc contains information that is not considered CBI ,while the second disc contains all responsive information that is CBI. Responsive information is included in the respective subfolders- identified as "Item 1" on each ofthe discs. As noted above, U. S
. EPA collected information that is responsive toAttn: Compliance Tracker, AE-17J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 3 this Request when it visited the facility on April 18, 2012. Also as noted above, in addition to the responses provided on the disc identified as CBI, U. S. Steel respectfully requests that all photographs taken during the site visit be treated as Confidential Business Information (CBI). 2. U.S. EPA REQUEST: For the time period January 1, 2010 to December 31, 2011, provide manufacturing specifications and operating data to demonstrate operating parameters for each of the facility's indurating furnaces. Operating parameters and data must include, at a minimum: flue gas composition, entrance air temperature, exit air temperature, preheat zone temperature, burner temperature, pellet residence time, and airflow rate). U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 2. 3. U.S. EPA REQUEST: For the time period January 1, 2007 to December 31, 2011, provide records ofthe natural gas used by each specific indurating furnace at the facility. U.S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 3. 4. U.S. EPA REQUEST: For the time period January 1, 2007 to December 31, 2011, if coal was used as afuel source at the facility, provide documentation ofthe average sulfur content for coal used by each specific indurating furnace at the facility. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder

- Item 4. 5. U.S. EPA REQUEST: If not already included in the Section 114 Information Request Response to be sent to EPA by April 18,2010 [sic], provide copies of all stack tests conducted on any emissions unit for any reason, and include all test runs, even if a full test series was not completed. Identify the emissions unit; specify the date of the test, test method used, and the filter temperature during the time of the test, if applicable. Provide all calculations relative to the stack test, and provide copies ofthe full test report, including the section describing the process parameters and production or processing rates at the time ofthe test as well as copies ofany reports of visible emission observations conducted during each test. For each test during which the source was not operating at maximum designAttn : Compliance Tracker,AE-17

### J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 4 capacity, provide an explanation why production was not operating at maximum design capacity. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 5. 6. U.S. EPA REQUEST: Provide an electronic Excel workbook with the complete nitrogen oxide (NOx ) and sulfur dioxide (S02) facility-wide potential to emit calculations. Include in the response awritten description of how each column in the Excel workbook is generated. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 6. 7. U.S. EPA REQUEST: The facility's Best Available Retrofit Technology report, available on the Minnesota Pollution Control Agency Regional Haze website ("BART report"), discusses the facility's wet scrubbers for S02
. Provide all documentation, including reports and studies, to determine the current S02 efficiency of all water scrubbers at the facility. Additionally, provide all documents, including reports and studies, completed for the technical feasibility of efficiency upgrades for each scrubber. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 7. 8. U. S. EPA REQUEST: The BART report discusses the technical feasibly of low NOx burners and a variety of selective catalytic reduction (SCRs) systems. Provide all documentation , including reports and studies, to determine the technical feasibility of low NOx burners and SCRs at the facility's indurating furnaces. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 8. 9. U.S. EPA REQUEST: The BART report discusses the technical feasibly ofoverfire air and induced flue gas technology. Provide all documentation, including reports and studies, to determine the technical feasibility of overfire air and induced flue gas technology at the facility's indurating furnaces. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 9. 10. U. S. EPA REQUEST: Identify the manufacturer, including contactAttn : Compliance Tracker,AE-17J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 5 information, for all low NOx burners, SCR, scrubber, overfire air, and induced flue gas technologies considered technically feasible for use at the facility. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 10. 11 . U. S. EPA REQUEST: Forthe time period January 1 , 2002, to the date of receipt ofthis letter, provide all documentation, including engineering studies or mass balance studies, conducted to determine emissions of NOx from each waste-gas stack at all indurating furnaces at the facility: U. S. STEEL RESPONSE: Please see the attached two discs for information that is responsive to this request. The first disc contains information that is not considered CBI, while the second disc contains all responsive information that is deemed CBI. Responsive information is included in the respective subfolders- identified as "Item 11" on each of the discs. 12. U. S. EPA REQUEST: Provide an electronic Excel workbook listing the following information from the NOxand/or S02 continuous emissions monitoring system (CEMS) from the date the CEMS were installed to present. Provide the information on an hourly basis, where applicable. The Excel workbook must include the following : a. CEMS identifying name or marker; b. CEMS location; c. Pollutant monitored; d. Date and time; e. NOx / S02 emissions rate in pounds per million British thermal units (lb/mmBtu); 

### f. Raw NOx/ S02 in ppm; g. NOx/ S02 emissions rate in pounds per hour; h. Flow rate in actual cubic feet per minute (acfm); and i. Furnace temperature in F. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 12.Attn : Compliance Tracker,AE-17J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 6 13. U. S. EPA REQUEST: Provide written explanation and supporting documents of how the facility could use NOx CEMs for process optimization. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 13. 14. U.S. EPA REQUEST: Forthe period from January 1, 2002, to the date of receipt ofthis letter, provide NOxemissions data from each indurating furnace for each day, and also for a thirty-day rolling average. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 14. 15. U. S. EPA REQUEST: Identify all NOx emission sources and factors contributing to NOx emissions at the facility's indurating furnaces, including but not limited to, the burners. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 15. 16. U.S. EPA REQUEST: Identify all persons, including employees, consultants, representatives ofthe taconite industry, or representatives of air pollution control manufacturers, who assisted in the preparation, or were consulted for the purpose of preparing, the BART report. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 16. The following requests and responses relate to the lowNOxburners on the facility's Line 6 indurating furnace. 17. U.S. EPA REQUEST: What is the Total Capital Investment, the Total Annual Cost (including Total Indirect Annual Cost and Direct Annual Cost), annual emission reduction, and average cost effectiveness ($/ton)? Total Capital Cost and Total Annual Cost are as defined in EPA's Air Pollution Control Cost Manual (EPA/452/B-02-001, January 2002)
.Also, to what extent would the costs, and $/ton, be lower for a subsequent Low NOx main burner because much ofthe engineering/design work on the low NOx burners on Line 6 and 7 would not need to be repeated. U.S. STEEL RESPONSE: Please see the attached disk in the subfolder- Item 17. 18. U. S. EPA REQUEST: Provide any test results and a description of any otherwork done to improve the performance ofthe Line 6 Low NOx Main Burner, especially for burning coal and natural gas or biomass, subsequentAttn: Compliance Tracker, AE-17

### J Air Enforcement and Compliance Assurance Branch April 24, 2012 Page 7 to what was reported in the December 1 , 2011, Line 6 Low NOx Main Burner Final Report. U. S. STEEL RESPONSE: Please see the attached disk in the subfolder - Item 18. A certification statement regarding this correspondence and all attachments is provided on the following page. The files in the attached disk, where appropriate, are provided as Word documents or in PDF format with Optical Character Recognition (OCR) capability. The files provided in the attached compact disk are virus free based upon U. S. Steel's virus protection software, Norton by Symantec®. Although U. S
. Steel originally sought a USEPA extension to May 7, 2012 to supplement its response with information that it believed it would be unable to compile by April 24, 2012, U. S
. Steel has expedited its review and believes it has satisfied the information request with the enclosed information. If any additional information is found prior to May 7 which is responsive to the request, a supplemental submittal will be made. If USEPA has any questions related to the information submitted, please feel free to contact Chrissy Bartovich at (218) 749- 7364.

Enclosures cc: C. Bartovich (USS) (w/enclosures) S. Campbell (USS) (w/o enclosures) D. Smiga (USS) (w/o enclosures)

(418004) T. Woodwell (USS) (w/o enclosures) M. Dzurinko (USS) (w/enclosures) 

# s jJJ)j

David W . HackerCERTIFICATION I certify under penalty oflawthat I have examined and am familiarwith the information in the enclosed documents, including all attachments. Based on my inquiry ofthose individuals with primary**respon~ibility** for obtaining the information, I certify that the statements and information are, to the best ofmy knowledge and belief, true and complete. I am aware that there are significant penalties for knowingly submitting false statements and information, including the possibility offines or imprisonment pursuantto section 113(c)(2) oftheAct, and 18 U.S.C
. 

### §§ 1001 and 1341 .

# ~**~**

# homas Kelly, General Manager United States Steel Corporation Minnesota Ore Operations

Date