Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 1 of 17 

## Narrative Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Compan y Received April 6 th 

## , 2012

Items from Appendix C are restated below in italic print with Hibbing Taconite Company ’s response directly following each.

1. 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 det ailed 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 of the image in the photograph. Photographs mus t correspond to each of the process stages described.

The following describes the mining, crushing, concentrating and pelletizing operations at Hibbing Taconite. A diagram of the entire process, entitled Process Diagram.pdf , can be found
in the folder en titled Question 1, as are all additional diagram materials mentioned or referenced in Question 1. Photographs of the process are included in the document titled
Pho tographical Process Diagram.pdf

, and are referenced in the below narrative as alphanumeric codes in parentheses.

General Overview Hibbing Taconite Company (HTC) is an iron ore pellet producer that mines, concentrates and pelletizes taconite for use in the steel industry. Key process components include the mobile equipment fleet, two primary c rushers, nine autogenous grinding mills, and three straight

- grate indurating furnaces. HTC is located north of Hibbing, MN on approximately 34,000 acres of land, which includes a 7,000 acre tailing basin and 6,000 acre open pit mine. HTC is managed by Cl iffs Mining Company

.
Overview of Mining and Concentrating Processes Crude ore is mined in the pit (A1) and transferred to the primary crusher (B1) where it is

reduced in size to

– 10” chunks. The ore is then conveyed to the surge pile (B2) and on to the Concentrator where it is finely ground in autogenous grinding mills (C 1). The ore is further concentrated in a series of roughers (C2), cyclones (C3), finishers (C4), fine screens (C5) and a vertimill grinding circuit (C6). During this process, the crude ore that contains approximately 30% iron is upgraded to iron ore conc entrate that contains 65% iron. The non

- magnetic material from the Concentrator is sent either to the cobber reject pile (C7) or to the tailing basin (C9). A hydroseperator (C8) is used to separate the course tails from the fines before entering

the tail ing basin. The cobber rejects are low

- magnetic material, which is used for tailing basinResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 2 of 17 dam construction or mining equipment site leveling. The final concentrate slurry is pumped to the concentrator thickener (C10).

Overview of Pelletizing Process
The t hree Dravo Lurgi straight grate indurating furnaces are functionally equivalent and all follow an identical process pattern. From the concentrator thickener, the concentrate slurry is pumped to the filtering section of the Pellet Plant. Small amounts of limestone a re injected while approaching the filters

, approximately 0.1% by weight while producing standard compression pellets, and 0.4% by weight while producing high compression pellets. The limestone is added to enhance fired pellet physical quality. The concentrate and limestone slurry is then pumped to the vacuum disc filters (D1) and dewatered to around 9.1% moisture. The concentrate (D2) is then conveyed to the storage bins (D3) located in the Pellet Plant balling

area.

When leaving the storage bins

, small amounts of bentonite (D4) are added and mixed with the concentrate before being conveyed to the balling dru ms (D6). Bentonite is a binder which
absorbs water and aids in the formation of the green balls, i t also gives the green balls addition al strength to withstand the indurating process. In the balling drum

, small amounts of water (D5) are added to promote the growth of the green balls to the desired size (93%

- 1/2”+3/8”) (D7). The iron ore green balls are then conveyed (D8) and screened (D 10) before entering the straight
grate

- indurating furnace (D9).

The pellets are then dried with 500 F process gases (D12,D15), and preheated with 1,750 F process gases. Natural gas is used in the firing section (D13) of the furnace to indurate standard pellets at 2,300 F, while high compres sion pellets require 2,400 F. To achieve required quality specifications higher temperatures are sometimes required as a result of the ore characteristics. After firing, the pellets are cooled with ambient air and discharged from the furnace (D16). The pellets are then conveyed (D18) to the pellet load out bins (D19).

Approximately 30 percent of the fired pellets are screened and returned to the feed end of the straight grate machine. These are called hearth layer pellets and are added to the traveling grate (D14) before the green balls at a thickness of approximately 3 inches. Twelve to thirteen inches of green balls are added on top of the hearth layer pellets at the feed end of the furnace. The hearth layer pellets protect the grate from overheating in the firing zone and improve the process airflow distribution th rough the pellet bed.

Each furnace has four stack vents (D21). Exhaust from the furnaces is vented through two ducts: the hood exhaust and the windbox exhaust. The hood exhaust handles updraft drying which gets its air from the cooling zone and some r ecirculated cooling gases, and the windbox exhaust handles downdraft drying which gets its air from the firing zone gases. The windbox exhaust flows through a multiclone, and then is combined with the hood exhaust stream in aResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 3 of 17 common header, which is subseq uently mixed and divided into four streams leading to four separate venturi rod scrubbers. These four venturi

- wet scrubbers clean all of the process gases exiting the furnace before entering the waste gas stacks.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth, David Brooks, Kenneth Rancourt, Jeffery Jones, and Matth ew Quinn.
P hotographs from EPA’s site visit on 4/17/12 were repurposed for this docume nt . A dditional photographs and narrative language were produced by HTC Environmental Department by ; Tara Helms and Kimberly Westerhoff

. Scott Gischia of Cliffs and Counsel were consulted in preparation of this response. In addition

, process description inf ormation was collected from the following sources: HTC BART Report, facility description from Air Emission Permit
No. 13700061

- 005, historical stack te sts, historical reports file d by HTC

, as well as consulting current HTC employees.

2. For the time period January 1, 2010 to December 31, 2011, provide manufacturing specification 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 com position, entrance air temperature, exit air temperature, preheat zone temperature, burner temperature, pellet residence time, and air flow rate.

Process operating data is included on the worksheet entitled Process Data 2010

- 2011.xlsm . Flue Gas Compositi on can be found in the Excel Spreadsheet entitled Flue Gas Composition.xlsx. Both documents can be found in folder entitled Question 2. The following notes are provided for context and interpretation of the data in that worksheet.

1. HTC did not operate during the first three months of 2010 due to global economic conditions and thus no operating data is available for that time period.

2. Cell values indicating “[

- 11059] No Good Data For Calculation”, or “#VALUE!” indicate periods when the furnace was not in operation.

3. HTC does not continuously monitor exit air temperature at the stack and thus no data is available for this parameter.

Table 2

- 1 display s the currently targeted furnace operating parameters.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 4 of 17 Table 2

- 1. Specification s targeted for each furnace parameter.

Parameter Normal

Operating Range Normal Operating Region

Entrance Air Temperature (Ambient Air) - 40F to +110F Entrance Air for the furnace is simply outside air.

Preheat Zone Temperature 1600F

- 1900F Temperatures are targeted between 1750F and 1950F with oxidation happening most rap idly around 1800F. Preheat Zone Temperatures change with pellet type, feed, chamber (burner) temperatures and outside air temperatures. T argets

are based on pellet type and quality.

Burner Temperatures (North and
South Chamber Temperature) 2200F

- 2450F High compression burner temperatures begin at 2400F. Standard compression burner temperatures begin at 2300F.

Pellet Residence Time (Contingent on Grate Speed) Grate Speed 7

to 10 ft per
minute No target: Contingent on furnace and quality demands.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth, D avid Brooks, and Jeffery Jones, and Cliffs’ HTC Environmental Department consisting of Tara Helms

. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

3. For the time period January 1, 2007 to December 31, 2011, provide records of the natural gas used by each specific indurating furnace at the facility.

Please see attached Excel Spreadsheet entitled Gas Use 2007

- 2011.xlsm found in folder entitled Question 3.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth, David Brooks, and Jeffery Jones, and Cliffs’ HTC Environmental Department consisting of Tara Helms. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

4. For the time period January 1, 2007 to December 31, 2011, provide documentation of the average sulfur content for coal used by each specific indurating furnace at the facility.

Coal is not used at Hibbing Taconite.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 5 of 17 Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Environmental Department consisting of Tara Helms. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

5. 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; spec ify 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 of the full test report, including the section describing the proces s parameters and production or processing rates at the time of the test, as well as copies of any reports of visible emission observations conducted during each test. For each test during which the source was not operating at maximum design capacity, prov ide an explanation why production was limited.

Page 2 of EPA’s request letter states “We are requesting information on the facility’s furnaces and other nitrogen oxide (NOx) and sulfur dioxide (SO2) emitting units at the facility.” As such, the response to this question has been provid ed consistent with that request and focuses on
SO2 and NOx stack te st information from the indurating furnaces at the facility

. Hibbing Taconite Company’s Stack Tests Table 5

- 1 is listed below, and all stack tests in their entirety are attached in the folder entitled Question 5.

Emission unit data, test dates, test methods, applicable temperatures, calculations, and process data are contained within each individual stack test report. There were two tests where
maximum de sign capacity parameters were not met . The first was the December 2007 test conducted by Barr Engineering on Furnace Line 2. The second was the June 2008 test conducted by Barr Engineering on Furnace Lines 1 and 3. The purpose of these tests were to test variable furnace conditions, including low tonnage, to induce NOx emissions variability in order to develop a predictive equation as part of a 2008 Voluntary Administrative Order with MPCA. The conditions forced in this series of testing are representativ e of the outer edges of normal operating conditions. A list of these forced conditions has been provided in the document
entitled Forced Conditions from L2 Dec 2007 NOx testing.pdf located in the Folder labeled
Question 5. Due to these conditions HTC fail ed to meet its product quality specifications during the testing period s , and therefore these test results are not representative of our normal operations.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 6 of 17 Table 5

- 1: NOx and SO2 Source Testing Summary

Test Date EU ID Current SV ID * Source

Description NOx

Test SO2 Test Report Title

May

- 87 EU 020

EU 021 SV021

- SV024

SV025

- SV028 Furnace Lines

1 and 2 X X 1987_PP_PM,NOX,SO2,CO,PB, ORSAT,MOISTURE,BERYLLIUM.pdf

May

- 94 EU 020

EU 021 SV021

- SV024

SV025

- SV028 Furnace Lines

1 and 2 X X 1994_PP_L1_L2_PM,NOX,SO2, CO,PB,VOC,Opacity,Total Hydrocarbon,TSP.pdf

Jun

- 94 EU 021 SV025

- SV028 Furnace Line 2 X X 1994_PP_L2_PM,NOX,SO2,CO,PB, VOC,Opacity,TSP.pdf

Sep

- 94 EU 022 SV029

- SV032 Furnace Line 3 X X 1994_PP_L3_PM,NOX,SO2,CO, PB,VOC,Opacity.pdf

Oct

- 97 EU 020

EU 021 EU 022 SV021

- SV024

SV025

- SV028 SV029

- SV032 Furnace Line

1 and 2 and 3 X 1997_PP_L1_L2_L3_NOX,CO2, O2.pdf

Aug

- 99 EU 021 SV025

- SV028 Furnace Line 2 X X 1999_PP_L2_PM,NOX,SO2,CO,PB, VOC,VE.pdf

Nov

- 99 EU 022 SV029

- SV032 Furnace Line 3 X X 1999_PP_L3_PM,NOX,SO2,CO,PB, VOC.pdf

Aug

- 04 EU 021 SV025

- SV028 Furnace Line 2 X X 2004_PP_L2_PM,NOX,SO2,CO,PB, VOC,VE.pdf

Aug

- 05 EU 020

EU 022 SV021

- SV024

SV029

- SV032 Furnace Line

1 and 3 X X 2005_PP_L1_L3_PM,NOX,SO2,CO, VOC,VE.pdf

May

- 07 EU 020

EU 021 EU 022 SV021

- SV024

SV025

- SV028 SV029

- SV032 Furnace Lines

1 and 2 and 3 X 2007_PP_L1

- 3_NOX.pdf

Dec

- 07 EU 021 SV025

- SV028 Furnace Line 2 X 2007_PP_L2_NOX.pdf

Jun

- 08 EU 020

EU 022 SV021

- SV024

SV029

- SV032 Furnace Line

1 and 3 X 2008_PP_L1_L3_NOx.pdf located in sub folder entitled 2008_PP_L1_L3_NOx

Oct

- 10 EU 020

EU 021 EU 022 SV021

- SV024

SV025

- SV028 SV029

- SV032 Furnace Line

1 and 2 and 3 X X 2010_PP_L1_L2_L3_PM,NOX, SO2,CO,PB,VOC,VE.pdf

Oct

- 10 EU 020

EU 021 SV021

- SV024

SV025

- SV028 Furnace Line

1 and 2 X 2010_PP_L1_NOX_and_L1_ L2_PEMS_RATA.pdf located in subfolder entitled 2010_PP_L1_NOX_and_L1_ L2_PEMS_RATA

Jan

- 11 EU 020

EU 021 EU 022 SV021

- SV024

SV025

- SV028 SV029

- SV032 Furnace Line

1 and 2 and 3 X 2010_PP_L1_L2_L3_NOX.pdf

Oct

- 11 EU 020

EU 021 EU 022 SV021

- SV024

SV025

- SV028 SV029

- SV032 Furnace Lines

1 and 2 and 3 X 2011_PP_L1_L2_L3_NO2_to_NOX _ratio.pdf

* The values represented in the Current SV ID column represent SV ID's from HTC's current Air Emissions Permit.
Historic ally

, stack vents labeled : 5A

- 5D correspond to Line 1, 5E

- 5H to Line 2, 5J

- 5M to Line 3

.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 7 of 17 Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth, David Brooks, a nd Jeffery Jones and Cliffs’ HTC Environmental Department consisting of Julie Lucas, Tara Helms, and Kimberly Westerhoff. C onsultants conducting the testing include; Barr Engineering, Interpoll Laboratori es Inc., Braun Intertec, and GE. In addition, Scot t Gischia of Cliffs and counsel were also consulted in preparation of this response.

6. Provide an electronic Excel workbook with the complete nitrogen oxide (NOx) and sulfur dioxide (SO 2 ) facility

- wide potential to emit calculations. Include in the re sponse a written description of how each column in the Excel workbook is generated.

The facility has not been required to recently work through a formal potential to emit analysis and thus the information here represents a best estimate of potential to emit. The estimated facility

- wide potential to emit calculations for NOx and SO2 are p rovided in the attached Excel workbook HTC NOx and SO2 PTE.xlsx found in folder entitled Question 6. This document has been p repared as a stand

- alone workbook with emission calculations

. Note that the table only includes the three indurating furnaces

. N one of the space heaters at the facility are included because they are considered mobile sources (rented annually each heating season).

Information that was used or considered in preparation of this response was provided by: P aul Taylor of Barr Engineer ing and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff. Scott Gischia of Cliffs and counsel were also consulted in preparation of this response.

7

- 9. The following information is provided as common background for Questions 7, 8 and 9 of the 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 200 6 "Guidance f or Facilities Conducting a BART Analysis"; and

2. EPA's "Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations", July 6, 2005, specifically pages 391614 to 39170 of the Federal Register.

The document fro m MPCA entitled "Guidance for Facilities Conducting a BART Analysis" provided the basis and requirements for t he BART reviews. This document, MPCA BART Review Guidelines (A

- C).pdf

, specifies that the Taconite MACT is to be considered equivalent to BART fo r particulate sources subject to both rules. EPA's "Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations"

, BART Reissuance at 7 0 FR 39164

- 39172 (July 6, 2005) .pdf

, in combination with MPCA's guidance provided the five step BART review process, which was followed for the BART analysis in the BART Reports.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 8 of 17 In addition to these guidance documents, the BART Report relied on Section 6 of MPCA's 2003 "Potential Impacts o f the Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry in Minnesota." This document entitled

, BART and Ta conite Report from Barr 2003.pdf

, 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 of the Minnesota taconite plants, representatives of Indian

tribes and Non

- governmental organizations ( NGO's ) as well as o ther stakeholders.

Cliff's BART Reports also relied on the information contained in its Northshore Facility's permit for its 2005 Line 5 Reactivation Project

, Furnace 5 Restart Vol I sect 5 BACT.pdf . 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.

Also included are an email and attachments that shared with MPCA the potential NOx a nd SO2 technologies defined as available and applicable for further assessment in the facility

- specific BART analyses found in the document entitled 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf

.
Each of the background documents referenced herein are contained in the folder titled
Questions 7

- 9 Guidance documents of this R esponse, including: 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf

, BART and Ta conite Report from Barr 2003.pd f

, BART Reissuance

at 70 FR 39164

- 39172 (July 6, 2005). pdf

, Furnace 5 Restart Vol I sect 5 BACT.pdf

, and MPCA BART Review Guidelines (A

- C).pdf

.

Information that was used or considered in preparation of this response was provided by George Pruchnofski, Beth Havlik, Erik Boleman, Teresa Kinder, and Jack Kennedy of Barr Engineering and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff

. In addition, Scott Gischia of Cliffs and counsel were also consulted

.

7. The facility’s Best Available Retrofit Technology report, available on the Minnesota Pollution Control Agency Regional Haze website (“BART report”), dis cusses the low efficiency o f the facility’s wet scrubbers for SO 2 . Provide all documentation, including reports and studies, to determine the current SO 2 efficiency of all wa ter scrubbers at the facility. Additionally, provide all documents, including reports and studies, completed for the technical feasibility of efficiency upgrades for each scrubber.

Total sulfur control efficiency testing of the scrubbers at Hibbing Tacon ite has not been done. A study by MPCA entitled, “Evaluation of Minnesota Taconite Wet Scrubbers at Minntac, Keewatin Taconite, Hibbing Taconite, and United Taconite,” designated by Engesser Scrubber Evaluation[1].pdf

, was referenced regarding scrubber e fficiency, page 6 and the ability to improve the performa nce of existing scrubbers for SO2 removal , pages 11

- 14 along with input from Hal Taylor of STS Consultants as provided in an email

, Cost to Increase ScrubberResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 9 of 17 Efficiency.docx

, from Jack Kennedy (Barr) dated July 10, 2006

. The EPA CueCost Workbook Version 1.0 was relied upon to determine the relative cost of retrofitting existing facilities compared to new facilities.

Please see the attached documents entitled Cost to Increase Scrubber Efficiency .docx

, Engesser Scrubber Evaluation[1].pdf

, and CueCostWorkbook.pdf found in the folder entitled Question 7.

In addition, please find the documents 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf

, BART and Ta conite Report from Barr 2003.pd f

, BAR T Reissuance at 70 FR

3916 4

- 39172 (July 6, 2005) .pdf

, Furnace 5 Restart Vol I sect 5 BACT.pdf

, and MPCA BART Review Guidelines (A

- C).pdf in the folder entitled Questions 7

- 9 Guidance Documents that were also utilized in the preparation of the 2006 BART rep ort.

Information that was used or considered in preparation of this response was provided by: Barr Engineering in particular Erik Boleman , Beth Havlik, Teresa Kinder, George Pruchnofsk and Jack Kennedy and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff . In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

8. The BART report discusses the technical feasibility 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.

Low NO x Burners: See “Potential Impact of Federal Regional Haze and Best Available Retrofit Technology Rule on the Taconite Industry in Minnesota”, September 30, 2003 pages 45 and 60

– 62. As described in the BART report, page 29, application of low NOx burners w ould be limited to the preheating section of the furnace, where the temperature is less critical to product quality. If low NOx burners were to be applied in the indurating section of the furnace, the reduced flame temperatures associated with low NOx burn ers would adversely affect taconite pellet product quality. Therefore, low NOx burners are not considered a feasible option for Hibbing Taconite furnaces.

SCR: See budgetary estimate

, Vogt Vendor Budget Estimate (redacted).pdf

, from Vogt Power
dated Octobe r 28, 2005, and Potential Impacts of the Federal Regional Haze and Best Available Retrofit Technology Rules on the Taconite Industry in Minnesota report, page 46.

The availability and technical feasibility of both Low NOx burners and SCR were discussed as presented in the Agenda CCI BART Issues Meeting 08

- 09

- 06.pdf document.

Please find the attached document s entitled Agenda C CI BART Issues Meeting 08

- 09

- 06.pd f and Vogt Vendor Budget Estimate (redacted).pdf found in the folder entitled Question 8

. Also
included in Folder Question 8 is an email discussion outlining conversations with a Low

- NOx
burner vendor named 2Aug2006 Barr LNB Vendor Discussion.pdf

. In addition, please find the

documents 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf

, BART a nd Ta conite Report from Barr 2003.pd f

, BART Reissuance at 7 0 FR 39164

- 39172 (July 6, 2005) .pdf

, Furnace 5Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 10 of 17 Restart Vol I sect 5 BACT.pdf

, and MPCA BART Review Guidelines (A

- C).pdf in the folder entitled
Questions 7

- 9 Guidance Documents tha t were also utiliz ed in the preparation of the 2006 BART
report.

Information that was used or considered in preparation of this response was provided by: Barr Engineering in particular Erik Boleman

, Beth Havlik, Teresa Kinder, George Pruchnofsk and Jack Kennedy and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff . In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

9. The BART report discusses the technical feasibility of overfir e 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.

Overfire air and induced flue g as technology: See Northshore Line 5 Restart BACT report, page

A

- 5

- 33, and Metso representative e

- mail dated July 18, 2006.

Please see the attached document entitled Metso OFA Email.pdf found in the folder entitled Question 9. In addition, please find the documents 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf

, BART and Ta conite Report from Barr 2003.pd f

, BART Reissuance at 7 0 FR

39164

- 39172 (July 6, 2005) .pdf

, Furnace 5 Restart Vol I sect 5 BACT.pdf

, and MPCA BART Review Guidelines (A

- C).pdf in the folder entitled Questions 7

- 9 Guidance Documents that were also utilized in the prepara tion of the 2006 BART report.

Information that was used or considered in preparation of this response was provided by: Barr Engineering in particular Erik Boleman

, Beth Havlik, Teresa Kinder, George Pruchnofsk and Jack Kennedy and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff . In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

10

. Identify the manufacturer, including contact information, for all low NOx burners, SCR, scrubber, overfire air, and induced flue gas technologies considered technically feasible for use at the facility.

Please see the attached document entitled Manufacturers_contact_info(1).xlsx found in folder
entitled Question 10.

Information that was used or considered in preparation of this response was provided by: Barr Engineering in particular Paul Taylor, Beth Havlik, Teresa Kinder, George Pruchnofsk a nd Jack Kennedy and Cliffs’ HTC Environmental Department consisting of Tara Helms and Kimberly Westerhoff . In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

11. For the time period January 1, 2002, to the da te of receipt of this 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.

Please find the requested studies in Question 11 Folder: Folder Combustion Chamber Modification Project 1

- 26

- 06 Folder CTG Studies

– NOx Folder PEMS Development
Document HTC BART NOx Reduction Memo 2007

- 12

- 10 FINAL.pdfResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 11 of 17 Folder PEMS Work 2012

Information that was used or considered in prep aration of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth, David Brooks, John Hausman and Jeffery Jones ; consultants including; Barr Engineering in particular Beth Havlik, Andrew Skoglund, and Eric Boleman , Clean Combustion & Energy, Energy Systems Associates, Coleraine Minerals Research Laboratory, Cliffs Technical Group in particular Martin Hanninen, and the Cliffs Environmental Department consisting of Julie Lucas, Andrea Hayden, Tara Helms, and Kimberly Westerhoff. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

12. Provide an electronic Excel workbook listing the following information from the NOx and/or SO2 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 maker; b. CEMS location;

c. Pollutant monitored; d. Date and t ime;

e. NOx/SO 2 emissions rate in pounds per million British thermal units (lb/mmBtu); f. Raw NOx/SO 2 in ppm

g. NOx/SO 2 emissions rate in pounds per hour; h. Flow rate in actual cubic feet per minute (acfm); and
i. Furnace temperature in O F.

Hibbing Taconite does not currently operate, nor has it ever installed or operated NOx or SO2 CEMS, and thus has no response to this question.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth and David Brooks a nd Cliffs HTC Environmental Department consisting of Tara Helms, and Kimberly Westerhoff. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

13. Provide written explanation and supporting documents of how the facility could use NOx CEMS for process optimization.

As noted in its response to Question 12, HTC does not now , nor has it ever operated CEMS, and thus has no information at hand by which t o provide a response to this question.

However, discussion of this topic was included as part of the 2006 BART report and is reprinted
here for reference.

“Process Optimization with NOx CEMS or Other Parametric Monitoring ”

“ MPCA guidance lists “NOx CE MS” as a work practice/operational change for controlling NOx emissions. Based on conversations with MPCA staff, this work practice would include process adjustments, or optimization, to minimize NOx emissions. The impact of the process adjustments would b e measured using the NOx CEMS. This approach has been used in the electric utility industry to fine tune NOx emissions from boilers. It may also be possible toResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 12 of 17 measure the impact of the process changes using parametric monitoring. However, there are

severa l 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 of the process and therefore this process is different from a boiler.

 The quality of the process feed material to the furnace i s 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 of the furnace, independent of process operation variability. This indicates that NOx formation is not dependent upon controllable operating parameters. In the absence of

contr ollable parameters, process optimization would not be effective at controlling NOx
emissions.

 Process optimization for NOx reductions on an induration furnace is not a proven technology and is not commercially available as a method of NOx control. To date, NOx CEMS have not been documented as a control technology for induration furnaces. To meet the available and applicable BART analysis criteria, documentation of the control technology is needed.

 To the best of our knowledge, there are no documented evaluations of NOx emission reductions for induration furnaces by optimizing the process using either NOx CEMS or parametric monitoring. We understand the reductions MPCA is aware of include other variables, such as a fuel switch, that would have an impact alone, so the CEMS contribution hasn’t been isolated.

Based upon this information, there is no indication that further emission reductions would be achieved through the use of the 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.” (p

. 31

- 33, HTC BART Report)

The HTC BART report is available in its entirety in the folder titled Question 13.

Also included is an ema il from Barr Engineering outlining a discussion with regards to NOx generation and optimization with CEMS

, 12Jul2006 Barr Discussion of Process optimization.pdf

.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Environmental Department; Scott Gischia, Tara Helms, and Kimberly Westerhoff. In addition, counsel was consulted in preparation of this response.

14. For the period from January 1, 2002, to the date of receipt of this letter, provide NOx emi ssions data from each indurating furnace for each day, and also for a thi r ty

- day rolling average.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 13 of 17 Hibbing Taconite does not operate, nor has it ever installed or operated NOx or SO2 CEMS, and thus has no information by which to respond to this question.

Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Environmental Department consisting of Tara Helms. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.

15

. Identify all NOx emission sources and factors contributing to NOx emissions at the facility’s indurating furnaces, including but not limited to, the burners.

The primary NOx emission sources located at Hibbing Taconite are the Indurating Furnaces, refer red to as Furnace Line 1, Furnace Line 2, and Furnace Line 3. The only other sources of NOx are seasonal temporary heaters rented only during the winter season and are not discussed further.

Understanding of NOx generation in taconite indurating furnaces is relatively young as compared to more traditional burners in the power industr y, but continues to evolve. I ncluded documents entitled Formation of NOX in Iron Oxide Pelletizing Furnaces.PDF

, NOx Reduction in Industrial Heat Processing.pdf , Measure Pres entation Template[1].ppt, and Document NOx Emission Reduction during Pellet Induration by Fuel

- Addition to the green

- Pellet.pdf provide some insight on NOx formation principals. Also included is a May 12, 2006 email correspondence from Barr Engineering outlining a planned conference call to ‘discuss NOx emissions data’

, 12May2006 Barr Conference Call on Kiln NOx Emissions.pdf

.

Further

, HTC’s internal engineering staff considers the following factors, summarized in Table
15

- 1, as likely having more po tential for describing NOx formation in HTC’s furnaces

.

Table 15

- 1. Potential NOx Formation Factors

Furnace
Zone Potential

Factor Description Why these factors are key players Preheat Air Inlet Temperature Temperature of the air entering the firing

chambers. This is the pre

- heated process air to the burner. It is also the temperature of the air oxidizing the magnetite to hematite in the preheat zone. Formation of NOx generally is
understood to be related to

t emperature

. Transition
Zone Temperature Temperature of the air moving out of the

chamber to the bed (to hood).

Hood Temperature Temperature above the bed under the

burners, used to control the burners. Firing Firing Zone
Pressure Pressure in the firing zone above the bed. Pressure will indicate airflow. Airflow will indicate how much air (N2) is available to react at the high temperatures.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 14 of 17 Information that was used or considered in preparation of this response was provided by: Cliffs’ HTC Technical Services Department consisting of Dana Koth and David Brooks and Cliffs’ HTC Environmental Department; Tara Helms, and Kimberly Westerhoff. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this

response.

16

. Identify all persons, including employees, consultants, representatives of the 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.

Name Organization
Edward LaTendresse HTC Steven Rogers HTC David Skolasinski Cliffs Natural Resources Andrea Hayden HTC (at time of BART Report)
Katherine M. Laird HTC (former employee)
Beth Havlik Barr Engineering , Project Manager George Pruchnofski Barr Engineering, Principal in charge
Teresa Kinder Barr Engineering , Technical Resources Jack Kennedy Barr Engineering , Technical Resources
Erik Boleman Barr Engineering, Technical Resources

Information that was used or considered in preparation of this response was provided by: Barr Engineering in particular Erik Boleman, Beth Havlik, Teresa Kinder, George Pruchnofsk and Jack Kennedy . Cliffs’ HTC Environmental Department consisting of Tara H elms and Kimberly Westerhoff. In addition, Scott Gischia of Cliffs and counsel were consulted in preparation of this response.Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 15 of 17 

### Table of Contents: Accompanying Documentation for Narrative Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company

Folder Title Contents Question 1 Photographical Process Diagram.pdf

Process Diagram.pdf
Question 2 Flue Gas Composition.xlsx

Process Data 2010

- 2011.xlsm
Question 3 Gas use 2007

- 2011.xlsm
Question 4 * No Content Question 5 SubFolder 2008_PP_ L1_L3_NOx 2008_PP_L1_L3_NOx.pdf Line 1 NOx CEMS lb per hour 4

- 9

- 08 to 4

- 17

- 08.xlsx

Line 3 NOx CEMS lb per hour 3

- 31

- 08 to 4

- 8

- 08.xlsx SubFolder 2010_PP_L1_NOX_and_L1_L2_PEMS_RATA

2010_PP_L1_NOX_and_L1_L2_PEMS_RATA.pdf FL1 PEMS Spreadsheet (All Runs as Values).xlsx FL2 PEMS Spreadsheet (All Runs).xlsx

Furnace Line 1 Ref Method Data (low, mid, high temps).xlsx Furnace Line 2 Ref Method Data (low, mid, high temps).xlsx PEMS RATA Operating Data (Lines 1 2).xlsx 1987_PP_PM,NOX,SO2,CO,PB,ORSAT,MOISTURE,BERYLLIUM.pdf 1994_PP_L1_L2_PM,NOX,SO2,CO,PB,VOC,Opacity,Total Hydrocarbon,TSP.pdf 1994_PP_L2_PM,NOX,SO2,CO,PB,VOC,Opacity,TSP.pdf 1994_PP_L3_PM,NOX,SO2,CO,PB,VOC,Opacity.pdf 1997_PP_L1_L2_L3_NOX,CO2,O2.pdf 1999_PP_L2_PM,NOX,SO2,CO,PB,VOC,VE.pdf 1999_PP_L3_PM,NOX,SO2,CO,PB,VOC.pdf 2004_PP_L2_PM,NOX,SO2,CO,PB,VOC,VE.pdf 2005_PP_L1_L3_PM,NOX,SO2,CO,VOC,VE.pdf 2007_PP_L1_L2_L3_NOX.pdf 2007_PP_L2_NOX.pdf 2010_PP_L1_L2_L3_NOX.pdf 2010_PP_L1_L2_L3_PM,NOX,SO2,CO,PB,VOC,VE.pdf 2011_PP_L1_L2_L3_NO2_to_NOX_ratio.pdf Forced Conditions from L2 Dec 2007 NOx testing.pdf
Question 6 HTC NOx and SO2 PTE.xlsxResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 16 of 17 

### Table of Contents: Accompanying Documentation for Narrative Response to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company (Continued)

Folder Title Contents Questions 7

- 9 Guidance
Documents BART and Taconite Report from Barr 2003.pdf

BART Reissuance at 70 FR 39164

- 39172 (July 6, 2005).pdf Furnace 5 Restart Vol I sect 5 BACT.pdf 9May2006 Barr to MPCA SOx NOx Control Technologies.pdf MPCA BART Review Guidelines (A

- C).pdf Question 7 Cost_to_Increase_Scrubber_Efficiency.docx

CueCost Workbook.pdf Engesser_Scrubber_Evaluation[1].pdf Question 8 Agenda CCI BART Issues Meeting 08

- 09

- 06.pdf

2Aug2006 Barr LNB Vendor Discussion.pdf Vogt Vendor Budget Estimate (redacted).pdf
Question 9 Metso OFA Email.pdf
Question 10 Manufacturers_contact_info(1).xlsx Question 11 Folder Combustion Chamber Modification Project 1

- 26

- 06 to MPCA Submittal of Notification of energy and emission reduction project
Folder CTG Studies

- NOx

HibtacLines123NOxBalances.xls

Line3NOx.xls
Line3NOx25%PA.xls
Line3NOx50%Paxls
Line3NOx75%PA.xls

Line3NOx100%PA.xls Folder PEMS Development

Subfolder Alternative Method Proposals 2008

Alternative Method Proposal[1].pdf

Furnace Line 1 Alternative Method Proposal.pdf Furnace Line 2 Alternative Method Proposal.pdf Furnace Line 3 Alternative Method Proposal.pdf
Subfolder Additional Alternative Method Submissions 2009

NOx Alternative Monitoring Method 11

- 12

- 2009.pdf NOx Alternative Monitoring Method 12

- 9

- 2009.pdf NOx Alternative Monitoring Method Cover 11

- 12

- 2009 NOx Alternative Monitoring Method Cover 12

- 9

- 2009.pdfResponse to Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company Received April 6, 2012 Page 17 of 17 

### Table of Contents: Accompanying Documentation for Narrative Response to
Items Listed in Appendix C of EPA Request for Information Addressed to Hibbing Taconite Company (Continued)

Folder Title Contents Question 11 Folder PEMS Development (continued) (continued) Subfolder NOx Formation Project Analyze Phase[1].ppt Baseline Graphs(1).xls Control Phase[1].ppt
Define Presentation

- NOX Formation[1].ppt Improve Phase[1].ppt Measure Presentation Template[1].ppt 4Jun2010 PEMS Discussion Summary.pdf Testing PEMS using 24

- hr

- avg predictors.xls
Folder PEMS Work 2012

MINITAB.MPJ NOx PEM Writeup 2012.pdf

HTC BART NOx Reduction Memo 2007

- 12

- 10 FINAL.pdf
Question 12 * No Content Question 13 HTC BART.pdf

12Jul2006 Barr Discussion of Process optimization.pdf
Question 14 * No Content Question 15 Formation of NOX in Iron Oxide Pelletizing Furnaces.PDF

Measure Presentation Template[1].ppt NOx Emission Reduction during Pellet Induration by Fuel

- Addition to the green

- Pellet.pdf 12May2006 Barr Conference Call on Kiln NOx Emissions.pdf NOx Reduction in Industrial Heat Processing.pdf
Question 16 * No Content



### *There was no relevant content for the folders noted above.