November 26, 2013



### VIA E-MAILAND FEDERALEXPRESS The Honorable Gina McCa11hy Administrator U.S. Environmental Protection Agency Room3000 Ariel Rios Buildiog 1200 Pennsylvauia Avenue,N.W. Washington, D.C. 20004 Mr. Douglas Aburano Chief, AttainmentPlanning

and Maintenance Section AirPrograms Branch (AR-18J) U.S. Environmental ProtectionAgency 77 West Jackson Boulevard Chicago, Jllinois 60604



### Rc: Petition for AdministrativeReconsideration ofthePartialDisapproval ofAir Quality Implementation Plans for Regional Hazefor the States ofMichigan and Minnesota Cliffs Natural Resources Inc. ("Cliffs") herebypetitions the U.S. Environmental ProtectionAgency ("EPA" or "Agency") for reconsideration ofthe final rule entitled "Approval and Promulgation ofAir Quality ImplementationPlans; States ofMichigan and Minnesota; Regional Haze; Final Rule," which was published in theFederal Register at 78 Fed. Reg. 59,825 (Sept. 30, 2013) ("SIP Disapproval"). Cliffs operates four ofthe seven taconite processing facilities for which EPA has disapproved the state Best Available Retrofit Teclmology ("BART") determinations ofMinnesota and Michigan: three in Minnesota (Hibbing Taconite,N011hshore, and United Taconite) and one in Michigan (Tilden). Cliffs submitted extensive comments on EPA'sproposed SIP Disapproval to Docket Nos. EPA-ROS-OAR-2010-0037 and EPA-ROSOAR-2010-0954. Reconsideration is mandated under the Clean Air Act ("CAA'') 

### §307(d)(7)(B), which statesthat "theAdministrator shall convene a proceeding for reconsideration oftherule" whena person raising an objectionto a rule orprocedure can demonstrate that "it was impracticable to raise such objection orifthegrounds for suchobjection arose aftertheperiod for public conm1ent

... and ifsuch objection is ofcentral relevance to the outcome ofthe rule

...." Since the close ofthepublic commentperiod, additional information has become available regarding the availability and effectiveness oflow-NOxbumers ("LNBs") intaconite furnaces and the importance ofcase-by-case fimmce determinationswhen evaluating BART. This includes new information provided byU.S. Steel related to its Keetac furnaces and Minntac fiu·naces 3, 4, and 5 being submitted in a separatepetition for administrative reconsideration. This informationwas not available until after theclose ofthepublic commentperiod, and is of central relevance to thefinal rulebecause 

### itundercuts the assumptions EPAmade regarding the

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-status ofLNB technology that formed the basis for EPA's SIP DisapprovaL Inthis circumstance, the CAA mandates reconsideration. 1 Argument in Support ofCliffs' Petition Inf01mation that has become available since Cliffs submitted comments on EPA's proposed SIPdisapproval refutes EPA's assumptions regarding the technical feasibility ofLNBs for Cliffs' fumaces. This includes newinformation fi·om U.S. Steelthat burner retrofits at Keetac and at Minntac lines 3, 4 and 

### 5 are encounteringinsurmout1table obstacles to installing the LNB technology installed atMinntac lines 6 and 7. A technology is only considered "teclmically feasible" under EPA guidelines ifithas "been installed and operated for thetype of 

### source under review under similar conditions/, or "could be applied to the source under review." 40 CFR 51 App. Y § lV.D. The states appropriately excludedthem from further BART analysis at the time oftheirBARTdeterminations, and new infonnationconfirms the validity ofthose judgments

.. I. SignificantDistinctions between Furnaces 6 and 7 at Minntac. United Taconite, andTilden Rebut EPA'sTechnical Feasibility Conclusions for Grate-Kilns
Inarguing thatLNBs must be considered technically feasible for all grate-kilns because they have been installed onthe "same sourcetype" as furnaces 6 and 7 at Mim1tac, EPA erroneously assumed that the furnaces were operating under "similarconditions." Sincethe close ofthepublic comment period, Cliffs has been granted access to theU.S. Steel Minntac facility and discovered differences betweenthe operatingconditions atMinntac and the operating conditions at United Taconite and Tildenthatreinforce the importance ofthe required case-by-case evaluation ofretrofit technologies. U.S. Steel has experienced different operating conditions at Keetac and at Minntac's otherfurnaces as set fmth in their separatepetition for 

### reconsideration. First, the two Minntac fumaces thathave installed LNBs (Lines 6 a11d 7) also have small LNBs installed in the preheat sections oftheir furnaces, which are capable ofachieving very low NO,emissionrates (0.1-0.3 lb/MMBtu) with minimal threat to product quality. Thepreheat sections contribute approximately 30percentofthe totalheatinputto eachfurnace, which allows the Milmtac furnaces to maintain higherNO, rates at their main burners. United Taconite and Tildendo not operatepreheat burners, and therefore donot have the option ofreducing NOx in this manner. Instead, United Taconite and Tilden would need to achieve all NOx reductions fr-om the main burner. In orderto achieve the NOx reductions mandated by EPA in its FIP rule, the adjustments to the main burnerwould require enormous amounts ofexcess airto cool the flame and additional fuel consumptionto heatthat additional air. This would createhigher fuel penalties than thoseexperienced atMiimtac, estimated to be 25-45 percent for each fiu·nace. 

### See Declaration ofEric Wagner (Attachment B).

1This new information is also relevant to EPA's related BART FIP rulemaking, published at 78 Fed. Reg. 8706 (Feb. 6, 2013). Cliffs has aPetition for Reconsideration oftheBART FIP rule also pending before EPA and requests thatthe information contained herein also be considered as part ofthat reconsideration.

- 2-Second, theMinntac fumaces process a different type ofore thanthe furnaces atUnited Taconite and Tilden that reduces Minntac's fuel consumptionat lines 

### 6and 7. Minntac processes an ore with a highermagnetite content, whichcontributes heat to the kiln during oxidation (exothermicreaction). United Taconite processes ores with lowermagnetite concentrations, andTildenprimarilyprocesses hematite oresthat do not contributeheat to the furnace. As a result, Cliffs' furnaces are configureddifferently torecapture more heat and to efficientlyuse fuel to maintain furnace temperatures. Forthis reason, Cliffs' furnaces have fewer options for newefficiency improvementsto offset the LNB energypenalty than Minntac. In addition, Minntacwas ableto take advantage ofported kilns onits fumaces to help with pellet oxidation due tothe type ofore thatMinntac processes. Thisreduces the amount ofextra heat the furnace must produce to oxidizethepellets. United Taconite and Tilden cannot gainthis same benefitfrom installing portedkilns because ofthe types ofore they process. Forthese reasons, Metso has determined thatthe unacceptableenergy penalty associated with LNB installation atUnited Taconite and Tildencannot be offset byadditional efficiency improvements as occurred atMinntac. See Declaration ofEric Wagner (AttachmentB). As outlined in its own Petition for Reconsideration,U.S. Steel similarlyhas encountered technical feasibility issues while attemptingto apply the LNB teclmology installed at Minntac Lines 6 and 7 to otherfumaces thatdo notoperate ported kilns and thathave different burner configurations and process throughputs. U.S. Steel anticipates significantly higher costs and fuel penalties at these units, andhas raised similar concerns overpelletquality. These factors demonstratethat United Taconite and Tildenare not being operated nnder "similarconditions" as the furnaces atMinntac. Itwas therefore arbitraryfor EPA to determine thatLNBs were automatically "technically feasible" for all grate-kilnfurnaces. EPA has an obligation to reconsiderits SIP Disapproval to take into accountthe newinfom1ation presented here that undermines the premise for its action. 2. Cliffsis Unable to Locate Commerci;illyAvailableLNBs for its Grate-Kiln and Straight-Grate Fumaces EPA erroneously assumed in its SIP Disapproval that LNBs had eitherbeen "installed and operated for the type ofsource under reviewunder similarconditions," or "could beapplied to the sourceunderreview." 40 CFR 51 App. Y § IV.D. Cliffshas explained above that LNBs have neverbeen installed onsources similarto Cliffs' furnaces "under similar conditions," and therefore EPA can only find thatLNBs are technically feasible ifthey "couldbe applied" to Cliffs furnaces. This requires a finding thatthe LNBs are both "commerciallyavailable" and "applicable" to Cliffs' furnaces. Cliffs' extensive work to locate LNBs suitablefor installation in its furnaces, including substantial new effOtt sincethe end ofEPA's connnentperiod, demonstratesthatneither istme. Cliffshasnow spent 

### 18 months investigating LNB options for its three grate-kiln and five straight-gratetaconite furnaces. See Declaration ofPeter Suardini (Attachment A). Cliffs retained Metso Minerals, anengineeringcompany with broadexperience at taconite furnaces, to assistinthis investigation. Id Contraryto EPA's assumption, Metso reports that there are no off-the-shelf, commercially available LNB options for Cliffs' furnaces thatwillnot have

-3-unacceptable energypenalties or createproduct quality concerns. The manufacturer ofLNBsfor Minntac's grate-kilntaconite furnaces, Coen, confinned that it could notguaranteethat its burners would achieve the NO, reductions mandated byEPA without affecting pellet quality. 

### I d. Metso's analysis ofCoen'shigh stoich LNB technology concluded that it will result in an unworkable 25-45% energypenaltywhen applied to United and Tilden. See Declaration ofEric Wagner (Attachment B). Burnetmanufacturers have expressed interestinworking with Cliffs to develop lowNO, combustion technology, but each requiresfi1rnace-specific development ofa technology that requires pilot testing to determine ifpellet quality can be assured ata reduced NO,rate. This is a clear indicationthatLNB is in the early stages ofdevelopment for taconite furnaces and it does not qualify as an available retrofittechnology. After diligent research and substantial expense over more than a year, Cliffs hasbeen unable to identify a single burner onthe open marketthat can be installed in its straight-grate furnaces. Declaration ofEric Wagner (Attachment B); Declaration ofPeter Suardini (Attachment A). Thestates were correctin their assessmentthattheLNB technology being pilot tested in Cleveland Ohio without introducing pellets was too nascent to beconsidered BARTfor straight-grate taconitefurnaces. DespiteEPA's optimismoverthe usc ofLNB technology in these applications, reality has demonstrated that this technologyis not yet developed to the point that it is both commerciallyavailable and applicable to Cliffs' fi1rnaces. · EPAmaynot ignorehard evidence that its assumptionsregarding the teclmical feasibility ofLNBs were incorrect. EPA must address information that undermines its analysis. 78 Fed. Reg. at 59829. EPA'stechnical feasibility assumptions go to the heart ofits SIP Disapproval, making this anissue ofcentral relevance to the final rule. Conclusion Thank you for yourconsideration ofthe important issuesidentified inthis petition. The informationthat became available after the close ofthepubliccommentperiod regnrding the status ofLNB technology for taconite furnaces demonstrates beyond doubt that EPA'srationale for the SIP Disapproval was based on enoneous assumptions. In this circumstance, The Clean AirAct requires EPAto reconsiderthe SIP Disapproval and issue a decision that is in accord withthe evidence before the Agency.

# sm,;~c£~ tlielE. Long CliffsNatural Resources Inc.

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### DECLARATION OFPETER 

### SUARDINI

I, Peter Suardini, declare as follows:

1. My name is Peter Suardini, I am a Senior Staff Pyrometallurgical Engineer for Cliffs Technology Group (CTG), a division ofCliffs Natural Resources Inc. (Cliffs). 2. I earned Bachelor and Master of Science Degrees in Metallurgical Engineering from Michigan Technological University, in 

### the early 1980's. 3. 

### Jhave over 30 years ofexperience in design, installation, commissioning, & 

### operations of various mineral and thermal processing systems, at industrial coal and iron ore facilities. 4. I have been employed by Cliffs for 18 years, and have spent the past 15 years focused principally on optimizing and upgrading Cliffs' iron ore pelletizing furnaces, including a number ofprojects related to Cliffs' grate-kiln burner systems (at both Tilden and United Taconite). 5. Over the last 18 months, Cliffs has been conducting "case studies" (led by myself and others), to evaluate the feasibility ofLow NOx Burner (LNB) installations at each ofCliffs' three grate-kiln and five straight-grate indurating furnaces subject to BART. Cliffs also retained Metso Minerals ("Metso"), one ofthe world's foremost experts in taconite furnaces, to assist in these investigations. 6. Looking for Available LNB Technologies: Since June of2012, Cliffs has invested thousands ofhours and more than $700,000 evaluating available LNB**technol~gies** 

### for its taconite furnaces. Despite this investment, neither Cliffs nor Metso has located a commercially available LNB that can be installed at any ofCliffs' gratekiln or straight-grate furnaces without substantial energy penalties (25-45% when burning natural gas), retrofit costs, or potential significant pellet quality impacts. 7. LNB for Straight-Grate Furnaces: It 

### is public knowledge that Fives is developing a natural gas based, LNB system for use at the new Essar straight-grate furnace. This LNB system has not yet been installed or proven at any industrial iron ore pelletizing operation. The Fives' LNB system has merely been tested using a single small natural gas burner, on a pilot-test rig at Fives' laboratory facilities. The pilot burner is much smaller scale than those required in Cliffs' existing straight-grate operations. The pilot testing

### also was not done in the presence of any iron ore pellets, let alone on a continuously operating iron ore pelletizing furnace. 8. LNB for Cliffs Straight-Grate Retrofits: Based on a conceptual engineering "case study" (funded by Cliffs), Metso and Fives estimated that the fuel penalty associated with implementing the proposed Fives LNB system at Hibbing Taconite (Hibtac) L-1 furnace would be 16.5% (for natural gas burning). Based on the lack of any detailed furnace modeling, Metso was only willing to guarantee that the furnace retrofit fuel penalty will not exceed 25%, for permitting purposes. The proposed Fives LNB system will also require a new electrostatic precipitator (ESP) to clean the recirculated combustion air to the burners. The new ESP will have to be housed in a separate new building, since it will not fit within the existing footprint ofthe plant. 9. LNB for Grate-Kiln Furnaces: It 

### is also public knowledge that USX Minntac purchased and installed Coen prototype Low NOx kiln burners (LNB) on their L-7 and L-6 gratekiln furnaces. Minntac's LNB reports to the MPCA report to hl}ve partially-to-completely mitigated the fuel penalty (initially estimated at about I0% for natural gas burning), by increasing waste gas airflows, along with other energy optimization initiatives (including

some cooler modification projects). However, unlike Minntac, neither Tilden nor United Taconite (Utac) use preheat burners, and the kilns are not ported (like the Minntac L-6 and L-7 kilns). This discrepancy is mostly due to the differences in furnace designs and the type ofpellet products being produced. In 

### summary, preheat burners and ported kilns

are not applicable techuologies for Cliffs' grate-kiln furnace operations at Tilden and Utac. In Cliffs' furnaces, it is more energy efficient to have all the fuel and heatrequired for the process to be provided bythe kiln burners, and to have all the ambient air required for pellet oxidation and initial cooling to be provided in the primary cooling section. 10. LNB for Cliffs Grate-Kiln Retrofits: Based on conceptual modeling "case studies" (funded by Cliffs), Metso estimated that the "unmitigated" fuel penalty associated with implementing a Coen prototype Low NOx "gas" burner, on Tilden L-1 and Utac L-2 kilns is approximately 40-45%. Further conceptual modeling byMetso also indicated that

even significant increases in process fan airflows (resulting in dramatic changes in process temperatures and the overall process heat balance), will only "partially" mitigate the fuel penalty for the Tilden and Utac furnaces (the fuel penalties are still estimated to

### be in the 25-37% range). Due to fundamental difference in the Tilden and Utac furnace designs (compared to Minntac L-6 and L-7), the fuel penalty ofthe Coen LNB will be much greater and more difficult to mitigate in the Cliffs' furnaces. 11. At the present time, despite the significant residual negative impacts to the process energy efficiency, heat balance and other retrofit impact concerns, neither Fives or Coen have provided written guarantees that the LNB systems they propose to install on Cliffs' straight-grate and grate-kiln furnaces, will meet a NOx limit of<1.2#/MMBtu. 12. Similar to Minntac, Cliffs and Metso anticipate that a number ofthe process fan wheels and/or the associated motors will also need to be upgraded and/or replaced to facilitate the higher airflows required in the grate-kiln process. However, unlike Minntac, the Tilden and/or Utac furnaces will likely also require much more expensive ductwork, structural steel, power distribution, and dust collector "expansion" projects. 13. The burner(s) and furnace configuration are the "heart" of the indurating process, controlling the heat, time, and temperature profile, as well as all chemical reactions in the furnace; all ofwhich control resultant pellet quality. 14. Cliffs has completed Phase I conceptual LNB engineering "case studies" with bothFives and Coen, for the first Cliffs straight-grate and grate-kiln furnaces (Hibtac L- 1, Tilden L1, and Utac L-2). In all "case studies", Coen and Fives will not and cannot take the responsibility for the adverse impacts to Cliffs furnaces caused by their proposed prototype LNB systems (ie., fuel penalties, pellet quality/throughput impacts, downtime/derating costs, or other environmental issues). They defer to Metso and Cliffs to determine and mitigate those impacts. Equally concerning, is Metso's present inability to quantify those impacts, and/or guarantee that Cliffs operations will still be able to satisfy our customer's pellet quality specifications and production requirements in the merchant supplier market where Cliffs operates. 15. As such, the NOx reductions and energy efficiency improvements associated with these aspects ofthe Minntac furnaces cannot be replicated in the same way at Cliffs. Simply stated, the Minntac furnaces are materially different from the furnaces at United Taconite and Tilden.I declare (or certify, verify, or state) under penalty ofperjury under the laws ofthe United States ofAmericathat the foregoing is true andcorrect.

Executed November 26, 2013 By:

Peter Suardini Senior S!affPyrometallurgical Engineer Cliffs Natural ResourcesDECLARATION OF ERIC WAGNER 

### l, Eric Wagner, declare as follows: 1. 

### ·My name is Eric Wagner. l 

### am the Manager of Process Engineering for Metso Minerals Pyro Division ("Metso"). 2. Metso is a global expert in the design ofiron orepelletizing furnaces, having designed over 53 grate-kiln and 42 straight-grate furnace systems since its predecessor, Allis-Chalmers, first developed the pelletizing technology in the 1950s. 3. l have twenty five (25) years ofexperience in design, moditlcation, analysis, and commissioning of varied thermal processing systems including iron ore pelletizing (both Grate Kiln and Straight Grate Technology), lime calcining, coke calcining, and other minerals processes. During those 25 years I have evaluated the majority ofthe pelletizing furnaces in the United States and I am uniquely qualified to 

### compare the properties ofthese furnaces. 4. Metso has obtained new information regarding the unique characterisiics of the U.S. Steel Minntac furnaces ( 6 and 7) related to the generation and control of NOx emissions using LNB technology. Some ofthe information contained herein was disclosed to me during a November 22, 2013 teleconference with Cliffs engineering personnel whereby information was revealed to Cliffs during reciprocal visits to Cliffs' Tilden site and USS Minntac on July 10, 2013 and August 27, 2013, respectively. Additionally, new information was also recently obtained from engineering assessments performed by Coen and**Met~o** 

### Fives dated September 19, 2013 and June 4, 2013. This information reveals significant differences between these Minntac furnaces and other Grate Kiln 

### furnaces operated by Cliffs Natural Resources at United Taconite and Tilden that are relevant to the formaiion and control ofNO,emissions. 5. Minntac furnaces 6 and 7 operate preheat burners in addition to the large kiln burner. United Taconite and Tilden use a single kiln burner. Approximately 1/3 ofthe heat input from fuel for the Minntac furnaces is delivered at the preheat burners. Thesesmaller preheat burners can achieve very low NO, rates (0.1-0.3 lb/MMBtu) due to a more favorable NO, reduction combustion environment in the preheat zone as compared to the firing end ofthe kiln. The lower NOx generation ofpreheat burners allows the kiln burner to produce NO, levels above the plant overall NO, limits and still maintain overall NO, limits. An example ofhow this is achieved follows: (0.33 fraction ofheat from preheat burners) multiplied by (0.1 preheat burners Jb/MMBTU NOx rate) plus (0.67 fraction of heat from kiln burner) multiplied by (1.75 kiln burner lb/MBTU NOx rate) equals (1.2 lb/MMBTU overall NOx rate). The following calculations use the min and max NOx rates forpreheat burner. (0.33 x 0.1) 

### + (0.67 x 1.75) 

### = 1.2 and (0.33 x 0.3) 

### + (0.67 x 1.64) 

### = 1.2. From these calculations itcanbe shown that the kiln burner can produce 37% (1.64/1.2) to 45% (1.75/1.2) more NOx emissions and still maintain overall NOx limits. United Taconite and Tilden use only a single kiln burner, so they do not have the ability to shift NO, reductions to more easilyachieved NOxreduction with preheat burners. 6. Minntac furnaces 6 and 7 process high magnetite ore that contributes heat to the kiln when oxidized. Tilden's ores are primarily hematite, which is not a source ofheat for the kilns. United processes ores with a lower concentration ofmagnetite than Minntac. Therefore, Tilden's furnaces and United's furnaces must add more fuel to achieve final product requirements than Minntac. It follows that Cliffs has invested in fuel efficiency improvements to minimize this differential cost. Metso has determined that the energy penalty associated with heating the additional cool air introduced with the LNB technology in use at Minntac cannot be offset by additional energy efficiency improvements at United and Tilden. Those energy penalties are predictedto remain 25-45% for Cliffs' furnaces. 7. Minntac furnaces 6 and 7 use ported kilns to maximize the benefit oftheir high-magnetite ore bodies. Ported kilns allow the introduction ofadditional air directly to the kilns where it helps oxidize the high magnetite ore that Mi1mtac processes. United and Tilden do not use ported kilns because porting will not produce significant benefits for the type ofore they process. Ported kilns significantly change the heat balance ofthe furnace

### makingitdifficult to generalize from Minntac's experience at Tilden and United. 8. Mitmtac furnaces 6 and 7 are also Ullique because they produce high 

### flux magnetite pellets. By contrast, United produces primarily standard (low-flux) magnetite pellets. Tilden produces high flux hematite pellets. These furnaces are Ulliquely designed with heat sources and air flow to produce a quality pellet for their specitlc product. Retrofitting a furnace with the Coen-type LNB burner introduces more air, requires more fuel, and at different locations. As a result, the LNB retrofit must be evaluated in the context ofthe Ullique furnace design for that specific pellet product from that specific ore type. The Minntac experience cannot be generalized to other furnaces. Each furnace is a unique design project to determine if that type of burner can work without unacceptable pellet quality and energy penalty problems. 9. Current LNB burner technology for Tilden and United Taconite require additional air to reduce burner !lametemperature. The increased air at the kiln burner will through to the grate drying section. The increased airflow through the drying section will result in an increased pressure drop across the greenballs. Greenballs are defined as raw feed to indurating furnace. Undried greenballs have minimal strength, the higher bed pressure will deform the greenbal!s. Deformed pellets lower bed permeability causing restricted air flow, poor pellet heating and ultimately reduced pellet quality. In addition, spherical pellets are required for blast furnace operation where the pellets are used as raw feed for iron making. The increased air 

### flow in drying section will also increase green ball drying rate. Drying greenballs too quickly, will rapidly release water vapor, ie steam explosion, and cause pellet breakage. Rupture pellets lead to decreased in production rate due to generation ofUlluseable fines and reduced pellet quality. In order to maintain pellet quality, the overall dryer section air flow and drying rate must be limited. Limiting is accomplished by reducing the amoUJlt of recovered heat from cooler. This unrecovered heat mustbe replaced with additional burner fuel, hence compoUllding fuel requirements. 10. For Straight Grate furnaces, Low NOx burner (LNB) technology has beenpilottested by Fives North America in a prototype combustion chamberin Cleveland, Ohio, but LNB technology has not been installed to date on any Straight Grate furnace that is producing iron ore pellets. 11. The Coen burners installed at the Grate Kiln furnaces at U. S. Steel's Minntac facility cannot be used to retrofit Straight Grate furnaces because the two furnace designs are fundamentally different with regard to burner use and heatbalance. 12. Metso has continued to survey burner manufacturers with relevant experience in search of available teclmology for Straight Grate furnaces in recent months. Metso has concluded that no Low NO, techr1ology has been demonstrated commercially available for this type offurnace.

I declare (or certifY, verity, or state) under penalty ofperjury under the laws ofthe United States ofAmericathatthe foregoing is true and correct.

Executed November 26, 2013 Eric Wagner Manager ofProcess Engineering Metso Minerals Pyro Division