May 4, 2012

VIA FEDERAL EXPRESS
Attn: Compliance Tracker, AE-17J 

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# 72012 

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# ,;_J**--** AIR ENFORCEMENT BRANCH**~** U.S. EPA REGION 5
CU FFS NA TURAL RESOURCES Nocthsho:e Minong Company 10 Outo:o Drive, Silv er Bay,**~** 556 14 

# CLIFFS

P**8.226.~** 125 F 21S.22o.6037 cl ffsnatural!asources.com

Air Enforcement and Compliance Assurance Branch U.S. Environmental Protection Agency Region 5 77 W. Jackson Boulevard Chicago, Illinois 60604 Re: Request to Northshore Mining- Silver Bay, for Information Pursuant to Clean AirAct Section 114
Dear Mr. Czerniak:
This letter and the enclosed information are the response of Northshore Mining- Silver Bay (referred to herein as "NSM" or "Northshore") to Appendix C ofthe U.S

. EPA Region V Clean Air Act Section 114 Information Request (the "Request"), regarding the facility located at 10Outer Drive in Minnesota, which was received on April 6, 2012. The Request originally required a response within 15 days of receipt, but subsequent conversation and correspondence with Ms. Molly DeSalie of EPA staffon April 20, 2012 extended the deadlineforsubmittal to May 7, 2012. NSM hereby provides this timely response to the Request, with the understandings and clarifications noted herein. NSM has given careful consideration to this R equest and each of its questions to ensure that its response is

· properly tailored to the information EPA has requested. NSM has made a good faith effort to respond to this Request in the time allotted. To the extentthatthe response does not include ali ofthe information anticipated by your request, we ask that EPA first consider the information attached hereto and evaluate what, ifanything, may still be reasonably required underClean Air Act Section 114(a). To the extent that EPA identifies continuing needs for information, please contact us to discuss how we may further assist you. This response restates each ofthe questions in the Request and provides a narrative explanation of the responsive information as necessary. Responsive documents are referenced in the narrative and included with this fetter

. The attachments are organized by numeric references that correspond tothe questions below. Documents responsive to multiple questions are identified in the narrative response to each question, and are included under the question to which the documents are most responsive. The documents provided have been scanned for vi ruses using McAfee software.
Northshore Mining Companywishes to point outthat itis thethird in a sequence ofthree owners and operators ofthe Northshore iron ore mining and processing facilities. While thefacility commenced operations in the late 1950s as Reserve MiningCompany, Cyprus Minerals Company operated thefacility duringthe early 1990s. Northshore Mining Company assumed ownership duringOctober 1994 and has operated thefacilitysincethat time. In respondingtothe information request, w hen appropriate, Northshore has searched archived files from

U.S. Environmental Protection Agency Attn: ComplianceTracker, AE-17J Page 1the previous owners forthe requested information. Itis impossible for Northshoreto determine ifthese fi les are complete. Nevertheless, every attemptwas madeto provide a complete response to the inquiry. Additionally, it is Northshore's understanding thatthe information sought by EPA in this Request is focused on its taconite processing plant and, therefore, Northshore has prepared its responses with regards to those sources, rather than on the subsidiary power plant located on the NSM premises.

For the record, NSM notes thatwhile it has made a good faith effortto respond tothe Information Request, it does notwaive any of its rights to object tothe form and content ofthe Information Request or any legal defenses that it might have to this Information Request or its admissibility in any administrative orjudicial proceeding. To the extent,this Information Request is overly broad and unduly burdensome; itseeks information that is not relevant tothe compliance status ofitsfacility; it is vague and ambiguous, and requires that legal conclusions be madeto it, NSM objects to the Information Request on the groundsthat it exceeds U.S.EPA's authority under Section 114 ofthe Clean AirAct. NSM also objectsto the Information Request tothe extentthat it requests informationthat is sub jectto attorney-client privilege orotherapplicable privilege, orthat constitutes attorney work product or

# is otherwise notdiscoverable. Finally, to the extentthatthe questions are vague, ambiguous, overly broad or otherwise exceed U.S. EPA's authority under Section 114(a), NSM has made appropriate and reasonable effortsto respond to the questions tothe best ofits ability, and has made reasonable interpretations ofthe questions

. If you have any questions regarding this information, please contact Ms

. Andrea Hayden of my staff at (218)226-6032. Certification
I certify under penalty of law that I have examined and am familiar with the information in the enclosed documents, including all attachments. Based on my inquiry of those individuals with primary responsibility for obtaining the information, I certify that the statements and information are, to the best of my knowledge and belief, true and complete. I am aware that there are significant penalties for knowingly submittingfalse s tatements and information, including the possibility offines or imprisonment pursuant tosection 113(c)(2) oftheAct, and 18 

### u.s.

## c. §§ 1001 and 1341. Sincerely,

1James Korpi VP/General Manager
Enclosure

cc: JeffT. Connett,' Manager Air Quality Division Minnesota Pollution Control Agency S20 Lafayette Road North St. Paul, Minnesota 55155
Ms. Mary Gade, Gade Law Group Mr. Michael Long, Cliffs Natural Resources Mr. Scott Gischia, C liffs Natural Resources

U.S. Environmental ProtectionAgency Attn: ComplianceTracker , AE-17J

Page 2

### Narrative Response to Items Listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining- Silver Bay, Received April 6, 

## 2012
Items from Appendix Care restated below in italic print with Northshore Mining- Silver Bay's response directly following each.

1. 

### Provideprocessflow diagramsfor both the taconite iron ore mining and the taconitepellet manufacturingprocesses. Include in the description, at a minimum, information on the following: mining operations, ore transferandstorage, course ore crushing,fine ore crushing, ore classification screens, ore storage bins, grinding rod/ball mills, separation, thickeners, balling drums/pelletformation, induratingfurnace, pellet cooling andstorage, and theprocess boilers. Include a detailed narrativeprocess description andphotographs to explain the indurating furnace process (separatelyfor eachfurnace]. For each photograph; provide o coded diagram/map to clearly identify the location ofthe image in thephotograph. Photographs must correspond to each oftheprocess stages described.
The Adobe document titled "Question 1 Process Diagram.pdf" and Word document titled "Question 1 Process Pictures.docx" provided on the flash drive accompanying this Narrative Response includes a process flow diagram and related pictures for both the taconite iron ore mining and the taconite pellet manufacturing processes. The Word document titled "Question 1 Process Description.docx" provided on the flash drive accompanying this Narrative Response includes a description of mining operations, ore transfer and storage, coarse ore crushing, fine ore crushing, ore classification screens, ore storage bins, grinding rod/ball mills, separation, thickeners, balling drums/pellet formation, indurating furnaces, and pellet cooling and storage. The Word document titled "Question 1 Furnaces 11 and 12.doc" provided on the flash drive accompanying this Narrative Response is a detailed narrative process description with photographs for similar indurating furnaces number 11 and 12. The Word documenttitled "Question 1 Furnaces 5 and 6.doc" is a detailed narrative process description with photographs for similar indurating furnaces number 5 and 6. The Word document titled "Question 1 Furnace Diagram.docx" is a diagram that relates to the pictures in the furnace Word documents.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 2. 

### For the timeperiodJanuary 1, 2010 to December31, 2011, provide manufacturing specification and operating data to demonstrate operatingparametersfor each ofthefacility's indurating furnaces. Operating parameters and data mustinclude, at a minimum: flue gas composition, entrance air temperature, exit air temperature, preheatzone temperature, burner temperature, pellet residence time, and airflow rate. Response to Items listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 1 of 12The Excel workbook titled "Question 2.xslx" provided on the flash drive accompanying this Narrative Response includes daily average values ofstack entrance air temperatures, stack exit air temperatures, furnace preheat zone temperature, furnace ignition zone (burner) temperature, and stack air flow rates for each specific induratingfurnace at the Northshore Mining Silver Bay facility for the time period January 1, 2010 to December 31, 2011. Flue gas composition is derived from the most recent NOx or SOx stack test results and detailed in the same workbook. Residence time of pellets is not measured. However, forthe time period January 1, 2010 to December 31, 2011, the average residence time for pellets during normal operation in Furnaces 11 and 12 was approximately 31-43 minutes, Furnace 5 was approximately 28-39 minutes, and Furnace 6 was approximately 29-40 minutes. Northshore is unable to locate any documentation ofthe manufacturing specifications ofthe indurating furnaces. As stated in the cover letter, ownership ofthe facility by Cliffs was assumed in October 1994, and archived records of past owners are incomplete. Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 3. For the timeperiodJanuary 1, 2007to December31, 2011, provide records ofthe natural gas used byeach specific induratingfurnace at thefacility.
The Excel workbook titled "Question 3.xslx" provided on the flash drive accompanying this Narrative Response includes daily records ofthe natural gas used by each specific indurating furnace at the Northshore Mining- Silver Bay facility for the time period January 1, 2007 to December 31, 2011. The unit of measure is thousand cubic feet per hour, for the average of each day.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 4. For the timeperiodJanuary 1, 2007to December31, 2011, provide documentation ofthe average sulfur content for caal used by each specific induratingfurnace at thefacility.
Coal was not used as afuel source by any ofthe specific indurating furnaces at the Northshore Mining- Silver Bay facility for the time period January 1, 2007 to December 31, 2011. The indurating furnaces at the Silver Bay facility are not permitted to burn coal.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and, Jennifer Ramsdell of Cliffs. Scott Gischia ofCliffs and Counsel were also consulted.



### 5. 

### Provide copies of allstacktests conducted on anyemissions unit for any reason, and include off test runs, even ifa full testseries was not completed. Identify the emissions unit; specify the date ofthe test, testmethod used, and thefilter temperature during the time ofthe test, if applicable. Provide all calculations relative to thestack test, andprovide copies ofthefull test report, including the section describing theprocessparameters andproduction orprocessing rates at the time ofthe test, as well as copies of any reports ofvisible emission observations Response to Items listed in Appendix Cof EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April6, 2012 Page 2 of 12

### conducted during each test. For each testduring which the source was notoperating at maximum design capacity, provide an explanation whyproduction was limited. Page 2 of EPA's request letter states 

### "We are requesting information on thefacility'sfurnaces and othernitrogen oxide {NOx} andsulfur dioxide {502} 

### emitting units at thefacility." As such, the response to this question has been provided consistent with that request, and focuses on 50 2 and NOx stack test information from the indurating furnaces at the facility.
The table below is an index ofattached OCR documents each ofwhich is a complete stack test report. During each ofthe referenced stack tests, sources were not operating at maximum design capacity but rather within an acceptable range ofthe maximum practiced during the timeframe around which testing was conducted.

Furnace 12 Hood Exhaust Furnace 12 Waste Gas Dec-00 Furnace 6 X NOx 2000 SV 262 SV 113 SV EU 104 SV 104 Furnace 11 Waste Gas NOx 2005 SV 104 SV

X

EU 104 SV 104 Furnace 11 Waste Gas EU 104 SV 104 Furnace 11 Waste Gas EU 114 SV 114 Furnace 12 Waste Gas

Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.

Response to Items listed in Appendix Cof EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 3 of 12

### 6. Provide an electronic Excel workbook with the complete nitrogen oxide {NOx} andsulfurdioxide {502}

### facility-wide potential ta emit calculations. Include in the response a written description of how each column in the Excel workbook is generated.
The Excel workbook titled "Question 6.xlsx" provided on the flash drive accompanying this Narrative Response includes complete nitrogen oxide (NOx) and sulfur dioxide (502) facility-wide potential to emit calculations. Each column that includes data generated is referenced by a unique footnote providing a written description of how the data was generated.
Information that was used or considered in preparation of this response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining and Paul Taylor of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.

7-9. The following information is provided as common background for Questions 7, 8 and 9 ofthe Request. Additional information specific to each Question is further included in each section as appropriate.
As indicated in EPA's Section 114 Request, the BART Reports were developed in 2006 using control technology that was considered available and technically feasible at that time. In preparing the BART Report referenced in EPA's Questions 7 through 9, two guidance documents were relied on to establish the process and methodology. These were: 

### 1. MPCA's 2006 "Guidance for Facilities Conducting a BART Analysis"; and
2. EPA's "Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations", July 6, 2005, of70 Federal Register 391614 et seq., specifically pages 391614 to 39170.
The 2003 document from MPCA entitled "Guidance for Facilities Conducting a BART Analysis" provided the basis and requirements for the BART reviews. This document specifies that the Taconite MACT is to be considered equivalent to BART for particulate sources subject to both rules. EPA's "Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations" in combination with MPCA's guidance provided the five step BART review process, which was followed for the BART analysis in the BART Reports.
In addition to these guidance documents, the BART Report relied on Section 6 of MPCA's "Potential Impacts ofthe Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry in Minnesota." This document established the control technology available and technically feasible for the taconite industry in Minnesota. It was developed through a stakeholder process, which included members of MPCA, representatives ofthe Minnesota taconite plants, representatives of Indian tribes and NGO's as well as other stakeholders. Cliffs' BART Reports also relied on the information contained in its Northshore Facility's permit for its 2005 Line 5 Reactivation Project. This project required Best Available Control Technology (BACT) analysis for control of nitrogen oxides and sulfur dioxide emissions as part of its PSD permit. This BACT analysis is considered more rigorous than BART analysis. Response to Items listed in Appendix C of EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 4 of 12Each ofthe background documents referenced herein is contained on the flash drive accompanying this Narrative Response.
Also provided on the flash drive accompanying this Narrative Response are an email and attachments in an Adobe document titled "9May2006 Barr to MPCA SOx NOx Control Technologies.pdf' that shared with MPCA the potential NOx and S02 technologies defined as available and applicable for further assessment in the facility-specific BART analyses.

Information that was used or considered in preparation ofthis response was provided by Beth Havlik, Teresa Kinder and Jack Kennedy of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.



### 7. 

### Thefacility's BestAvailable Retrofit Technology report, available on the Minnesota Pollution ControlAgencyRegional Haze website ("BARTreport"), discusses the low efficiency ofthe facility's wetscrubbersfor 502• 

### Provide all documentation, including reports and studies, to determine the current502 

### efficiency ofall waterscrubbers at thefacility. Additionally, provide all documents, including reports andstudies, completed for the technical feasibility ofefficiency upgradesfor each scrubber.
Northshore's Silver Bay facility's current control for S02 is a wet electrostatic precipitator with a control efficiency of approximately 80%. Therefore, Northshore does not believe that this Question applies to it. Please refer to the Adobe document titled "Furnace 5 Restart BACT Analysis. pdf" and the electronic folder titled "BART NMC Furnaces PDF to MPCA" provided on the flash drive accompanying this Narrative Response for the background information. Also provided on the flash drive accompanying this Narrative Response is an Adobe document titled "10Jan2007 Barr S02 Scrubber Cost Adjustment.pdf" that includes an email from Barr Engineering summarizing some minor corrections to S02 scrubber cost estimates.

Information that was used or considered in preparation of this response was provided by George Pruchnofski, Beth Havlik, Jack Kennedy, Erik Boleman, and Teresa Kinder of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.



### 8. The BARTreport discusses the technicalfeasibility oflow NOx burners and a variety of selective catalytic reduction (5CRs) systems. Provide all documentation, including reports andstudies, to determine the technicalfeasibility oflow NOx burners and5CRs at thefacility's indurating furnaces.
The Adobe document titled "Potential Impacts ofthe Federal Regional Haze and BART Rules on the Taconite Industry in MN.pdf" provided on the flash drive accompanying this Narrative Response includes information regarding technical feasibility of low NOx burners. As described in the BART report on page 33, the indurating furnaces at Northshore Mining's Silver Bay facility Response to Items listed in Appendix Cof EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 5 of 12have a completely different combustion design compared to other furnaces. The indurating furnace design at Northshore Mining's Silver Bay facility do not separate the preheat zone from the combustion zone and temperature control is a controlling variable for operation. Because the temperature in the indurating zone is critical to product quality, and because this is dependent on the preheat zone operation, it is not practical to control the furnace conditions in the preheat zone adequately to make low NOx burners a feasible option at Northshore.
The Adobe documents titled "Vogt Vendor Budget Estimate (redacted).pdf' and "Potential Impacts ofthe Federal Regional Haze and BART Rules on the Taconite Industry in MN.pdf" provided on the flash drive accompanying this Narrative Response include information regarding the technical feasibility ofSCRs atthe Northshore Mining- Silver Bay facility.
The availability and technical feasibility of both Low NOx burners and SCR were discussed as presented 

### in the Adobe documentstitled "Agenda CCI BART Issues Meeting 08-09-06.pdf' provided on the flash drive accompanying this Narrative Response. Also provided on the flash drive accompanying this Narrative Response are Adobe documents titled "2Aug2006 Barr LNB Vendor Discussion.pdf" and "30Aug2006 Osmundson BART comments.pdf". The document titled "2Aug2006 Barr LNB Vendor Discussion. pdf" includes an email discussion outlining conversations with a Low-NOx burnervendor, and the document titled "30Aug2006 Osmundson BART comments.pdf" includes email correspondence from Mike Osmundson (Northshore Mining Company) discussing possible implications to furnace operation oftemperature in preheat region offurnace.
Information that was used or considered in preparation of this response was provided by George Pruchnofski, Beth Havlik, Jack Kennedy, Erik Bole man, and Teresa Kinder of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.



### 9. The BARTreport discusses the technical feasibility ofoverfire air and inducedflue gas technology. Provide all documentation, including reports andstudies, to determine the technical feasibility ofoverfire airandinduced flue gas technology at thefacility's induratingfurnaces.
The Adobe documents titled "Furnace 5 Restart BACT Analysis.pdf" and "Metso representative e-mail dated July 18, 2006.pdf' provided on the flash drive accompanying this Narrative Response includes information to determine the technical feasibility ofoverfire air and induced flue gas technology at the Northshore Mining- Silver Bay facility.
Information that was used or considered in preparation of this response was provided by George Pruchnofski, Beth Havlik, Jack Kennedy, Erik Boleman, and Teresa Kinder of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.



### 10. Identify the manufacturer, including contact information,for all lowNOx burners, SCR, scrubber, overfire air, and induced flue gas technologies considered technicallyfeasiblefor use at the facility.

Response to Items listed in Appendix C of EPA Request for Information Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 6 of 12The Excel workbook titled "Manufacturers_contact_info(l).xlsx" provided on the flash drive accompanying this Narrative Response identifies the manufacturer, including contact information, for low NOx burners, SCR, scrubber, overfire air, and induced flue gas technologies considered technically feasible for use atthe Northshore Mining- Silver Bay facility.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 11. For the timeperiodJanuary 1, 2002, to the date ofreceipt ofthisfetter, provide all documentation, including engineering studies ormassbalance studies, conductedto determine emissions of NOxfrom each waste-gasstackat all induratingfurnaces at thefacility.
The Word document titled "NOx Generation in Northshore Mining Furnaces.doc" provided on the flash drive accompanying this Narrative Response includes information from engineering studies to determine emissions of NOx from the indurating furnaces at the Northshore MiningSilver Bay facility.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 12. Provide an electronic Excel workbook listing thefollowing informationfrom the NOx and/or502 continuous emissions monitoringsystem (CEM5}from the date the CEM5 were installed to present. Provide the information on an hourly basis, where applicable. The Excel workbookmust include thefollowing: a. CEM5 identifying name ormaker; b. CEMS location; 

### c. Pollutant monitored; d. Date and time; e. NOx/502 

### emissions rate in poundspermillion British thermal units (lb/mmBtu); f. RawNOx/502 

### in ppm g. NOx/502 

### emissions rate in poundsperhour; h. Flow rate in actual cubic feetperminute (acfm); and i. Furnace temperature in °F.
The Excel workbook titled "Question 12.xslx" provided on the flash drive accompanying this Narrative Response includes the requested information pertaining to the NOx continuous emissions monitoring system (CEMS) installed on Furnace 5 from December 29, 2010 to present. The CEMS were initially certified on December 29, 2010. CEMS are not installed on any ofthe other indurating furnaces at the Northshore Mining Silver Bay facility.

Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 13. Provide written explanation andsupporting documents ofhow thefacility could use NOx CEM5 forprocess optimization. Response to Items listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 7 of 12Discussion ofthis topicwas included as part ofCliffs' Northshore 2006 BART report, and is reprinted here for reference.
"Process Optimization with NOx CEMS or Other Parametric Monitoring" MPCA guidance lists "NOx CEMS" as awork practice/operational change for controlling NOx emissions. Parametric monitoring is a possible derivative ofthis alternative. Based on conversations with MPCA staff, this work practice would include process adjustments, or optimization, to minimize NOx emissions. The impact ofthe process adjustments would be measured using the NOx CEMS. This approach has been used in the electric utility industry to fine tune NOx emissions from boilers. One taconite plant has installed NOx CEMS to monitor emissions but not to optimize NOx emissions through process fine tuning. That plant has experienced some reduction in NOx emissions butthese encompass multiple variables and are not directly attributed to process fine tuning with the NOx CEMS. Therefore, this alternative has not been demonstrated in the taconite industry.
There are several concerns with utilizing process optimization as an available, applicable and technically feasible control option for the taconite industry:


### •

•

• Taconite furnaces are designed and operated to convert magnetite to hematite in the presence of excess oxygen and require heat input to initiate the reaction which is exothermic and releases heat once initiated. Fuel combustion is only part ofthe process and therefore this process is different from a boiler.
The quality ofthe process feed material to the furnace is variable at some taconite operations and product quality may be compromised by attempting to fine tune heat input to minimize NOx formation.
At some operations, the operating parameters which generally influence the rate of NOx generation such as flame temperature, fuel usage and excess air are relatively constant during operation ofthe furnace, independent of process operation variability. This indicates that NOx formation is not dependent upon controllable operating parameters. In the absence ofcontrollable parameters, process optimization would not be effective at controlling NOx emissions.

Based upon this information, there is no indication that further emission reductions would be achieved through the use ofthe process optimization, using NOx CEMS or other parametric monitoring, as a control technology. Therefore, process optimization as a control option will not be evaluated further in this report." (P35-36, NSM BART Report)
The electronic folder titled "BART NMC Furnaces PDF to MPCA" provided on the flash drive accompanying this Narrative Response includes the Northshore Mining- Silver Bay facility's BART report in its entirety. Response to Items listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining -Silver Bay, Received April6, 2012 Page 8 of 12Also provided on the flash drive accompanying this Narrative Response is an Adobe document titled "12Jul2006 Barr Discussion of Process optimization.pdf" consisting ofan email from Barr Engineering outlining a discussion with regards to NOx generation and optimization with CEMS.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 14. For theperiodfrom January 1, 2002, 

### to the date ofreceipt ofthis letter, provide NOx emissions datafrom each induratingfurnacefor each day, andalsofor a thirty-day rolling average. The Excel workbooktitled "Question 14.xslx" provided on the flash drive accompanying this Narrative Response includes daily and thirty-day rolling average NOx emissions data for Furnace 5 from December 29, 2010 to the date of receipt ofthis letter. From January 1, 2002, to December 29, 2010, NOx emissions data for Furnace 5 is not available because CEMS were not installed during that time frame. NOx emissions data for the other indurating furnaces is not available because CEMS are not installed on them.
Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 15. Identify all NOx emission sources and factors contributing ta NOx emissions at thefacility's induratingfurnaces, including butnot limited to, the burners.
The Word document titled "NOx Generation in Northshore Mining Furnaces.doc" and the Adobe document titled "Formation of NOx in Iron Oxide Pelletizing Furnaces.PDF" provided on the flash drive accompanying this Narrative Response, identify possible NOx emission sources and factors contributing to NOx emissions in the indurating furnaces at the Northshore Mining- Silver Bay facility.
Also provided on the flash drive accompanying this Narrative Response is an Adobe document titled "12May2006 Barr Conference Call on Kiln NOx Emissions.pdf" consisting ofa May 12, 2006 email correspondence from Barr Engineering outlining a planned conference call to 'discuss NOx emissions data'.

Information that was used or considered in preparation ofthis response was provided by Ryan Siats and Jennifer Ramsdell of Northshore Mining. Scott Gischia of Cliffs and Counsel were also consulted.



### 16. Identify allpersons, including employees, consultants, representatives ofthe taconite industry, or representatives ofairpollution control manufacturers, who assisted in thepreparation, or were consultedfor the purpose of preparing, the BARTreport. Individuals who assisted in the preparation, or were consulted for the purpose of preparing, the BART report, included the following: Response to Items listed in Appendix CofEPA Requestfor Information Addressed to Northshore Mining- Silver Bay, Received April6, 2012 Page 9 of 12Information that was used or considered in preparation ofthis response was provided by George Pruchnofski, Beth Havlik, Jack Kennedy, Erik Boleman, and Teresa Kinder of Barr Engineering. Scott Gischia of Cliffs and Counsel were also consulted.

Response to Items listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 10 of 12

### Table of Contents: Accompanying Documentation for Narrative Response to Items Listed in Appendix Cof EPA Request for Information Addressed to Northshore Mining- Silver Bay

FolderTitle Question 1

Question 2 Question 3 Question 4 Question 5

Question 6 Question 7-9

Question 7

Question 8

Question 9 Contents Question 1 Furnace Diagram.docx Question 1 Furnaces 5 and 6.doc Question 1 Furnaces 11 and 12.doc Question 1 Process Description.docx Question 1 Process Diagram.PDF Question 1 Process Pictures.docx Question2.xlsx Question 3.xlsx No Documents Included NOx 2000 SV 262 SV 113 SV 114.pdf NOx 2005 SV 104 SV 261.pdf NOx 2006 SV 112 SV 114.pdf NOx 2007 July SV 104.pdf NOx 2007 SV March 104.pdf NOx 2009 SV 104 SV 114.pdf NOx 2010 EU 104 EU 114.pdf NOx 2011 EU 104 EU 114.pdf S02 2008

# sv 266.pdf Question 6.xlsx 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf EPA's Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations.pdf Furnace 5 Restart BACT Analysis.pdf MPCA's 2006 Guidelines for Facilities Conducting a BART Analysis. pdf Potential Impacts ofthe Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry in MN.pdf 10Jan2007 Barr S02 Scrubber Cost Adjustment NMC Furnaces BART Report Furnace 5 Restart BACT Analysis.pdf 2Aug2006 Barr LNB Vendor Discussion.pdf 30Aug2006 Osmundson BART comments.pdf Agenda CCI BART Issues Meeting 08-09-06.pdf Potential Impacts ofthe Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry in MN.pdf Vogt Vendor Budget Estimate (redacted).pdf Furnace 5 Restart BACT Analysis.pdf Response to Items Listed in Appendix Cof EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 11 of 12Question 10 Question 11 Question 12 Question 13
Question 14 Question 15

Question 16 Metso representative e-mail dated July 18 2006 Manufacturers contact info(1).xls NOx Generation in Northshore Mining Furnaces.doc Question 12.xlsx 12Jul2006 Barr Discussion of Process optimization.pdf NMC Furnaces BART Report Question 14.xlsx 12May2006 Barr Conference Call on Kiln NOx Emissions.pdf Formation of NOX in Iron Oxide Pelletizing Furnaces. pdf NOx Generation in Northshore Mining Furnaces.doc No Documents Included

Response to Items listed in Appendix Cof EPA Request for Information

Addressed to Northshore Mining- Silver Bay, Received April 6, 2012 Page 12 of 12