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 Company Received April 6th, 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 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 of the image in the photograph. Photographs must 

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 entitled Question 1, as are all additional diagram materials mentioned or 

referenced in Question 1. Photographs of the process are included in the document titled 

Photographical 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 crushers, 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 Cliffs 

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 (C1). 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 concentrate 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 tailing basin. The cobber rejects are low-magnetic material, which is used for tailing basin 
Response 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 three 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 are 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 drums (D6). Bentonite is a binder which 

absorbs water and aids in the formation of the green balls, it also gives the green balls additional 

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 (D10) 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 compression 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 through 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 recirculated 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 a 
Response 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 subsequently 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 Matthew Quinn. 

Photographs from EPA’s site visit on 4/17/12 were repurposed for this document. Additional 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 

information was collected from the following sources: HTC BART Report, facility description from Air Emission Permit 

No. 13700061-005, historical stack tests, historical reports filed 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 composition, 

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 Composition 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 displays 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. Specifications 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 rapidly around 1800F. Preheat 

Zone Temperatures change with pellet type, feed, chamber 

(burner) temperatures and outside air temperatures. Targets 

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, 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.

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; 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 of the full test 

report, including the section describing the process 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, provide 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 provided consistent with that request and focuses on 

SO2 and NOx stack test 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 design 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 representative 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 failed to meet its product quality specifications during 

the testing periods, 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 

subfolder 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.

Historically, 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, and Jeffery Jones and Cliffs’ HTC Environmental 

Department consisting of Julie Lucas, Tara Helms, and Kimberly Westerhoff. Consultants conducting the testing 

include; Barr Engineering, Interpoll Laboratories Inc., Braun Intertec, and GE. In addition, Scott 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 

(SO2) facility-wide potential to emit calculations. Include in the response 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 provided in the attached Excel 

workbook HTC NOx and SO2 PTE.xlsx found in folder entitled Question 6. This document has 

been prepared as a stand-alone workbook with emission calculations. Note that the table only 

includes the three indurating furnaces. None 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: Paul Taylor of Barr 

Engineering 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 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, specifically pages 391614 to 

39170 of the Federal Register. 

The document from MPCA entitled "Guidance for Facilities Conducting a BART Analysis" 

provided the basis and requirements for the BART reviews. This document, MPCA BART Review 

Guidelines (A-C).pdf, 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", BART Reissuance at 70 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 of the Federal Regional Haze and Best Available Retrofit Technology Rules on 

the Taconite Industry in Minnesota." This document entitled, BART and Taconite 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 other 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 and 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 Response, including: 9May2006 Barr to MPCA SOx 

NOx Control Technologies.pdf, 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, 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”), discusses the low efficiency of the 

facility’s wet scrubbers for SO2. Provide all documentation, including reports and studies, to 

determine the current SO2 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.

Total sulfur control efficiency testing of the scrubbers at Hibbing Taconite 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 efficiency, page 6 and the ability to 

improve the performance 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 Scrubber 
Response 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 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, 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 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.

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 NOx 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 would 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 burners 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 October 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 documents entitled Agenda CCI BART Issues Meeting 08-09-06.pdf 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 and Taconite 

Report from Barr 2003.pdf, BART Reissuance at 70 FR 39164-39172 (July 6, 2005).pdf, Furnace 5 
Response 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 that were also utilized 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 overfire 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 gas 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 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, 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 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 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.

11. For the time period January 1, 2002, to the date 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.pdf
Response 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 preparation 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 time;

e. NOx/SO2 emissions rate in pounds per million British thermal units (lb/mmBtu);

f. Raw NOx/SO2 in ppm

g. NOx/SO2 emissions rate in pounds per hour;

h. Flow rate in actual cubic feet per minute (acfm); and

i. Furnace temperature in OF.

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 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.

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 to 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 CEMS” 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 be 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 to 
Response 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 

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 of the process and therefore this process is 

different from a boiler.

 The quality of the 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 of the furnace, independent of process operation variability. This indicates that NOx 

formation is not dependent upon controllable operating parameters. In the absence of 

controllable 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 email 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 emissions 

data from each indurating furnace for each day, and also for a thirty-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, 

referred 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 industry, but continues to evolve. Included 

documents entitled Formation of NOX in Iron Oxide Pelletizing Furnaces.PDF, NOx Reduction in 

Industrial Heat Processing.pdf, Measure Presentation 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 potential 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 

temperature.

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 Helms 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.xlsx
Response 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.pdf
Response 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.