### 1 

# Regional Haze

State Implementation Plan Supplement

<March> 2012

### 2 Introduction

The state of Minnesota is home to two federal Class I areas, the Boundary Waters Canoe Area Wilderness (BWCAW) and Voyageurs National Park. In compliance with the Regional Haze Rule promulgated in 1999, the Minnesot a Pollution Control Agency (M PCA) submitted to the U.S. Environmental Protection Agency (EPA) a State Implementation Plan (SIP) to reduce haze in the Class I areas in December 2009.

The December 2009 submittal containe d Best Available Retrofit Techno logy (BART) determinations for several electric generating units (E GUs) and taconite facilities, in accordance with 40 CFR § 51.308(e). However, these BART determinations did not all have associated emission limits, due to a lack of available data. In addition, they were not yet enforc eable. On December 20, 2 010, the MPCA received a letter from EPA Region 5 indicating that, pursuant to the requirements of Section 110 of the Clean Air Act, BART limits must be established in an en forceable form before EPA can approve Minnesota’s Regional Haze SIP.

This submittal contains additional BART information and enforceable documents in fulfillment of the requirements of Section 110 of the Clean Air Act. In addition, this submittal contains a change in Minnesota’s strategy for the Northeast Minnesota Pl an, part of the long term strategy to improve visibility under 40 CFR § 51.308(d)(3)).

BART for Electric Generating Units

The MPCA’s December 2009 Regional Haze SIP submittal included BART determinations and associated emission limits for five power plants. Thes e plants are shown in the table below:

Facility Name Subject-to-BART Unit(s) Minnesota Power – Taconite Harbor EU 003 Minnesota Power – Boswell Energy Center EU 003 Northshore Mining Company – Silver Bay Power EU 002 Rochester Public Utilities – Silver Lake EU 003, EU 004 Xcel Energy – Sherco EU 001, EU 002

However, the emission limits were not included in enforceable documents, and therefore have not yet been acted on by EPA. This supplemental SIP make s changes to the BART determinations for power plants in Minnesota.

The MPCA’s initial intent was to determine that the Clean Air Interstate Rule (CAIR) was equivalent to BART for the power plants in Minnesota. EPA had de termined that emissions reductions from CAIR would result in greater reasonable progress towards visibility goals than site-specific application of BART. Therefore, states could essentially “substitute ” the participation of the state’s power plants in CAIR for individual BART determinations. The initial draft Minnesota SIP, which was placed on notice in February 2008, included this CAIR=BART determin ation. One of the reasons that the MPCA felt comfortable making this determination is that many emission reductions were already occurring in preparation for CAIR.

### 3 After the completion of the public notice period, the DC Circuit Court of Appeals remanded the CAIR program to EPA. Part of that action questioned whether Minnesota was appropriately included in CAIR, and EPA subsequently removed Minnesota from the CAIR program.

Because of the removal of Minnesota from CAIR, th e MPCA made individual BART determinations for the subject facilities. These BART determinations were described in the initial SIP submittal, but the emission limits were not included in enforceable documents at that time. In general, these BART determinations simply expressed emission limits from control projects that were being undertaken in planning for CAIR.

Minnesota is now included in the Cross-State Air Poll ution Rule, also known as the Transport Rule (TR), as described in 40 CFR § 52.1240 and 40 CFR § 52.124 1. EPA has committed to doing a rulemaking to determine if the emission reductions provided by the Transport Rule are equivalent or better than applying BART to power plants on an individual basis.

The emission budgets proposed for the TR are very similar to those proposed by EPA for CAIR. For example, under CAIR, Minnesota would have had an annual NO X 

### budget of 31,443 from 2009 through 2014, and 26,203 in 2015 and later. Under TR, Minnesota’s annual NO X 

### budget is 28,977. CAIR also proposed to use Title IV acid rain allowances, on a 2:1 basis, to reduce SO 2 

### emissions. Minnesota’s Title IV allocation is 97,181, so the annual SO 2 

### budget under CAIR would have been 48,950 tons per year. Minnesota’s SO 2 

### allocation under TR is 41,139 tons per year.

Because the TR is as stringent as CAIR, it is reason able to assume that EPA’s rulemaking will determine that the emission reductions from TR will be equivalent or better than those provided by source-specific BART. Therefore, the MPCA is determining that Transport Rule=BART for Minnesota. Rather than complying with the specific BART determinations madein the initial SIP submittal, Minnesota’s subjectto-BART power plants simply need to comply with th eir obligations under the Transport Rule in order to meet the BART obligations.

The MPCA believes that this determination will not have an adverse impact on the emission reductions or air quality expected due to the application of BART . The majority of the MPCA’s BART determinations for EGUs were based on the technolo gy that facilities were planning to install in order to comply with the Clean Air Interstate Rule. The MPCA believes that each facility will continue to have an incentive to operate the controls in order to comply with the Transport Rule.

BART for Taconite Facilities

In the submittal of December 2009, the MPCA dete rmined that, generally, BART for the taconite facilities consisted of operation of existi ng scrubbers to control sulfur dioxide (SO 2 

### ) emissions, good combustion practices to control nitrogen oxides (NO X 

### ) emissions, and continued implementation of the taconite Maximum Achievable Control Technology (M ACT) standard for contro l of particulate matter (PM) emissions.

However, due to a lack of good data on emissions at the taconite facilities, the MPCA was unable to develop emission limits to correspond with the BART determinations NO X 

### at all cases and for SO 2 

### in the case of facilities that burn higher sulfur fuels. Th e MPCA entered into Administrative Orders with the facilities, which required the facilities to do in creased monitoring of their emissions and report emissions to the MPCA.

### 4 The MPCA felt that at least one year of emission s data was needed from ea ch facility in order to determine the appropriate BART limits. After receiving enough emissions data from the facilities, the MPCA analyzed the emissions to determine the BART limits.

The general approach to setting the BART limits was to focus on a recent set of at least 150 hours of data. A confidence interval was then constructed, and the BART limit was set at the 99% upper prediction limit of the confidence interval. Table 1 li sts the subject-to-BART unit(s) at each facility, the BART determination for SO 2 

### and NO X 

### , and the resulting emission limit.

Memos describing the process for setting the BART emission limits for each facility, including more detailed information on the statistical analysis, ar e included as Appendix 1. Administrative Orders making the BART limits for all three pollut ants enforceable are included in Appendix 2.

The MPCA is requesting that EPA approve the attach ed Administrative Orders in Appendix 2, which contain BART emission limits and compliance method s, into Minnesota’s SIP. The MPCA also requests that EPA not incorporate the Administrative Orders requiring additional emissions monitoring into the SIP, as those Orders represented an interim step towards BART implementation.

Termination of the prior Orders by Consent is included in this SIP revision as Appendix 3. The Orders in this supplemental SIP contain all necessary requirements for ongoing implementation of BART.

United Taconite This supplemental SIP revision includes a slight change in approach for BART at United Taconite, due to a modification at the facility. In August 2010, the MPCA processed a permit amendment for United Taconite. The permit amendment allowed the concentr ator and pellet plant at United Taconite to be modified in order to increase plant production from 5.3 million long tons of pellets annually to 6.0 million long tons. It also allowed for the use of solid fuels on Line 1, which had previously been fired only with natural gas. This authorization for solid fuels includes the testing of alternative fuels, such as a wood-based fuel.

The change in the facility made it difficult to determine the appropriate BART limit. The MPCA determined that it was appropriate to make an initial finding of emission limits corresponding to the BART determination in the initial SIP submittal, based on the configuration of the facility at that time.

The permit amendment requires that, within 120 days af ter receiving notification of the BART emission limits set by the MPCA, United Taconite must undertake one of three options. The options are: 1) submit a permit application to MPCA to incorporate the BART limits; 2) su bmit a permit application that proposes emission limits for a BART alternative that provides greater controls of visibility impairing pollutants than the BART determination; or 3) submit an updated BART analysis for both Line 1 and Line 2 for the facility as changed by the permit amendmen t. The MPCA notified United Taconite of the BART limits on September 22, 2011.

On December 8, 2011, United Taconite proposed that the NO X 

### and SO 2

### limits set as part of the abovementioned permit amendment be incorporated as the BART limits for the facility. As described in the memo in Appendix 1, the MPCA found that these li mits provided greater annual reductions of NO X 

### and SO 2 

### than would be provided by the MPCA’s initial BA RT limits. Therefore, the MPCA is proposing to accept these as the BART limits for United Taconite, with the addition of a shorter averaging time for the NO X 

### emissions at the facility.Table 1: Taconite BART Determinations and Emission Limits for NOXand SO2Facility Unit StackVent NOXBARTNOXBARTLimitSO2BART SO2BART LimitArcelor Mittal InduratingFurnaceEU026 SV014,SV015,SV016,SV017Good combustion practices, low NOXburners in the pre-heat zone,furnace energy efficiency project(2007)1018.0 lbs/hr Existing wetscrubber0.165 lbs/LTHibbingTaconiteLine 1 PelletizingFurnaceEU020 SV021,SV022,SV023,SV024Good combustion practices, furnaceenergy efficiency projects (2005 and2006)447.4 lbs/hr Existing wetscrubber0.207 lbs/LTLine 2 PelletizingFurnaceEU021 SV025,SV026,SV027,SV028Good combustion practices, furnaceenergy efficiency projects (2005 and2006)571.7 lbs/hr Existing wetscrubber0.207 lbs/LTLine 3 PelletizingFurnaceEU022 SV029,SV030,SV031,SV032Good combustion practices, furnaceenergy efficiency projects (2005 and2006)338.3 lbs/hr Existing wetscrubber0.207 lbs/LTNorthshoreMiningInduratingFurnace 11EU100,EU104SV101,SV102,SV103,SV104,SV105Good combustion practices 115.5 lbs/hr Existing wetscrubber0.0651 lbs/LTInduratingFurnace 12EU110,EU114SV111,SV112,SV113,SV114,SV115Good combustion practices115.5 lbs/hr Existing wetscrubber0.0651 lbs/LTProcessBoiler#1EU003 SV003Existing controls0.17 lbs/MMBtuN/AN/AProcessBoiler#2EU004 SV003Existing controls0.17 lbs/MMBtuN/AN/AUnited Taconite Line 1 PelletIndurationEU040 SV046 Good combustion practices, pastheat recuperation project4.5 tons perdayExisting wetscrubber106.3 tons, 30-day rolling sumLine 2 PelletIndurationEU042 SV048,SV049Good combustion practices10.1 tons perdayExisting wetscrubber, Fuelblending197 tons, 30-day rolling sum6Facility Unit StackVent NOXBARTNOXBARTLimitSO2BART SO2BART LimitU.S. Steel -KeetacPhase II Grate-KilnPelletizingFurnaceEU030 SV051 Existing combustion controls andfuel blending12.35 tonsper dayExisting wetscrubber2.71 tons perdayU.S. Steel–MinntacLine 3 InduratingFurnaceEU225 SV103 Good combustion practices, fuelblending7.85 tons perdayExisting controls 1.28 tons perdayLine 4 InduratingFurnaceEU261 SV118 Good combustion practices, fuelblending, low-NOXburners in thepreheat zone9.85 tons perdayExisting controls1.10 tons perdayLine 5 InduratingFurnaceEU282 SV127 Good combustion practices, fuelblending, low-NOXburners in thepreheat zone9.46 tons perdayExisting controls1.10 tons perdayLine 6 InduratingFurnaceEU315 SV144 Good combustion practices, fuelblending, low-NOXburners in thepreheat zone7.14 tons perdayExisting controls1.47 tons perdayLine 7 InduratingFurnaceEU334 SV151 Good combustion practices, fuelblending, low-NOXburners in thepreheat zone5.51 tons perdayExisting controls1.61 tons perday

### 7 Long Term Strategy: Northeast Minnesota Plan

The December 2009 SIP submittal incl udes, as part of the long term strategy, the Northeast Minnesota Plan to reduce emissions of SO 2 

### and NO X 

### from large sources in the six county (St. Louis, Lake, Cook, Carlton, Itasca, and Koochiching) northeast Minnesota area.

The Northeast Minnesota Plan has two main componen ts. The first is a goal of a 30% reduction in combined SO 2 

### and NO X 

### emissions from larger sources, those that emit over 100 tons per year of either pollutant, by 2018 as compared to a baseline year of 2002. There is an interim goal of a 20% reduction by 2012. As of 2009, the most recent year for which em ission inventory data is available, emissions were down by 39%. Based on projections at the beginnin g of 2011, it appears Minnesota will meet both the 20% by 2012 and 30% by 2018 goals.

The second part of the Northeast Mi nnesota Plan laid out a strategy fo r pilot testing emission controls on the taconite plants. Based on the BART analyses provided by the taconite facilities, the MPCA determined that the six taconite facilities were like ly to be undercontrolled. Very few emission control technologies have been demonstrated on the indurat ing furnaces, the main source of emissions at the taconite facilities. Therefore, the Northeast Minnesota Plan envisioned that the taconite facilities would investigate control measures and pollution preventi on practices through pilot testing, and report to MPCA on the feasibility and cost effectiveness of th e controls. Any reasonable controls would then be installed. This was intended to evol ve the controls available for these fa cilities, as no other driver for reductions appeared to be likely.

The basic timeline envisioned for the pilot testing was that the taconite facilities would conduct the pilot testing during the end of 2011 and through 2012. They woul d then report to the MPCA on the results in early 2013, and the MPCA would review those reports. Any control measures th at were determined to be reasonable using the five factor s set forth in the Regional Haze rule would be required, and the MPCA would develop enforceable documents for those reductions from mid-2013 to mid-2014, with controls being installed in 2015 and onward.

However, since the original SIP submittal, EPA has issued two new National Ambient Air Quality Standards (NAAQS), for SO 2 

### and NO 2 

### , which appear able to drive more stringent controls and on a faster timeline than envisioned by the pilot testing. Ther efore, the MPCA is reconsidering the future progress of emission reductions from the taconite industry. We believe efforts to demonstrate compliance with new federal standards will result in appropriate ev olution of control technolo gies and other practices that reduce emissions and meet the overall objective of the Northeast Minnesota Plan.

Assuming additional emission controls are implemented in order to meet new ambient air standards and other requirements, pilot testing of additional controls should not be necessary. Therefore, the MPCA is working with the taconite facilities to ensure each facility will be able to demonstrate compliance with the NAAQS for NO 2 

### , and SO 2 

### in a time frame based on EPA’s attainment date for the new one-hour standards.

The Administrative Orders in Appendix 2 contain, in addition to the BART emission limits, requirements for modeling. Each facility must provide to MPCA a modeling protocol describing how modeling will be

### 8 conducted for NO X 

### and SO 2 

### emissions. 1 

### The Order then goes on to require that each facility provide, by the end of 2012, the following information:

• Modeling that demonstrates complianc e with the one-hour standards;

• Proposed emission limits that result in modeled compliance;

• A description of the work practices or controls that must be implemented to meet the emission limits; and

• A schedule for implementation which ensures that they will be in place and the emission limits achieved by June 30, 2017.

The MPCA is substituting this NAAQS based strategy fo r the pilot testing strategy laid out in the original SIP submittal. The requirements to demo nstrate attainment with the NAAQS for NO X 

### and SO 2 

### standards sets a bright line goal for emission reductions. Ultimately, the MPCA believes that this NAAQS strategy will result in the demonstration of emission control technologies that work well at taconite facilities, and will result in greater emission redu ctions more quickly than envisioned under the pilot testing strategy.

1 In some cases, MPCA already has a modeling protocol in house and therefore the Order does not require an additional protocol.

### Appendix 1: BART Determination MemosDEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### November 30, 2011 Office Memorandum

TO: 

### AQD File No. 257 (Delta ID No. 13700062)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### Nitrogen Oxides BART Limits for ArcelorMittal Steel Company

This memo was prepared to provide the documentation of the MPCA’s NO X 

### BART limit determination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information

1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address
ArcelorMittal Steel USA 1 South Dearborn Street Chicago, IL 60603 ArcelorMittal Mino rca Mine Inc. 5950 Old Highway 53 North Virginia, MN, St. Louis County Contact: Ms. Jaime Baggensto ss, Phone: (218) 749-5910 x283

1.2 Description of the Facility ArcelorMittal Minorca Mine Inc. (Arcelor) owns and operates a taconite pellet production plant. There are three main areas where emissions are created: the mine, tailings basin and pellet plant. Arcelor makes fully fluxed pellets using one straight grate furnace.

The major steps in taconite pellet production include ta conite ore mining, crushing, grinding, concentrating, agglomerating, and indurating. The larger sources of air emi ssions at Arcelor are from the indurating furnace operations and from mining activities, with lesser amounts from other processing operations and fugitive dust sources, including haul roads and the tailings basin.

Arcelor’s pellet plant has one Dravo indurating furnace. It burns a maximum of 370 MMBtu/hr of natural gas and is capable of handling 400 tons of pellets per hour.

2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

### The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology available and associated emission reduct ions achievable. The analysis must take into consideration the technology available, the costs of compliance, the energy and non-air quality environmental impacts, any pollution control equipment in use at the source , the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The unit for which the MPCA must determine BART and establish a NO X 

### BART limit consistent with that determination is:

Emission Unit Name EU Number 1 

### Control Equipment & Stack Numbers 2 

### Indurating Furnace EU026 SV014, SV015, SV016, SV017

2.3 The BART Determination

The MPCA’s NO X 

### BART determination for this unit, as documented in Appendix 9.3 of the December 2009 Regional Haze SIP submittal, is good combustion practices, past installation of Low NO X 

### Burners in the preheat zone and implementation of furnace energy efficiency projects in early 2008. However, due to the lack of sufficient emissions data representing the range of operating conditions that influence emissions, the MPCA did not set an emission limit at the time of making the BART determination.

Instead, the MPCA and Arcelor entered into an Administra tive Order, under which Arcelor provided additional NO X 

### emission information to the MPCA.

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NO X 

### emission information provided by Arcelor. The MPCA focused analysis on a set of 157 hourly NO X 

### emission data points collected in March 2008. Under the previously ment ioned Administrative Order, Arcelor was required to collect “a minimum of 150 one-hour data poin ts under the range of [furnace] operating parameters that influence NO X 

### emissions. The range of each operating parameter during testing should be representative of furnace’s operating range for the parameters in the 12 months previous to testing.” This requirement was to ensure that the emissions data collected was appropriately representative of the range of operating conditions for the furnace. The data was collected through simultaneous testing of each of the four furnace stacks, and continuously measured data was used to calculate four 15-minute averages for each ho ur. Then, an hourly average level was calculated for each hour.

The process of calculating the BART limit for Arcelor’s indurating furnace began by constructing a 99% confidence interval and taking the upper prediction level. The MPCA believes the use of a 99% upper predictive level for setting the limit is appropriate, due to the need for limits to be me t during all operating conditions, including during times of startup, shutdown, and malfunction.

1 The MPCA organizes conditions and illustrates associations in its permits using the Emission Unit (EU), Control Equipment (CE), and Stack/Vent (SV) numbers.

2 The indurating furnace has no control equipment for NO X emissions.

### The example calculation below shows the 99% upper prediction level:

Mean of 30 data points ൌ Χ ത ൅ ሾ2.608 ൈ ߪ ൈ ඨ ሺ 1
30 ൅ 1
157 ሻሿ

• Where Χ ത and σ are, respectively, the mean and standard de viation of the sample of 157 hourly-averaged
NO X 

### data points in the 2008 testing;

• The value 2.608 is the 2-tail percentage point of the t-distribution with a level of significance of 0.01 and 156 degrees of freedom; and

• ට ሺ ଵ

ଷ଴ 

### ൅ ଵ

ଵହ଻ 

### ሻ is used to relate the sample sizes for the intended compliance test and the 2008 data set.

The table below shows the descriptive statistics for the sample data, taken during March 2008.

Arcelor Mittal NO X 

### Stack Test Values (in lbs/hour)

# Data Points 157
Mean 994.1
St Dev 31.2 Max Value 1060.5 Min Value 909.4 99% Interval UPL 1010.3

The MPCA conducted additional analysis in order to help alle viate concerns that any one stack test, even an extended stack test, cannot capture all anticipated furnace operating co nditions. This was done through the use of bootstrapping, a resampling technique designed to replicate the taking of multiple samples of the same size from a population. This technique uses the 157 data points as a representative population, from wh ich multiple samples of 30 data points are drawn. A random number generator was used to select the hourly data points used in constructing each 30 data point sample. A total of 2000 sets of 30 hourly data points were generated. The mean of each 30 point data set was then used to make a new, larger, sample of 2000 data points to represent the over all “population” of potential emission levels. This was repeated several times, both in Excel and using the R statistical package.

Each of the surrogate populations thus cr eated had a different standard error. St andard error is the standard deviation of a summary statistic, or a measure of the precision of the estimate. So, in essence, the variability of the standard error for each of these surrogate populations gives a sense of how much the sample mean may differ from the “true” or population mean. In the bootstrapping technique, the standard error of a 30 point data set built from the new surrogate population (built from the mean of ea ch of 2000 randomly selected 30 data po int sample sets) ranged from 5.670 to
9.269.

The MPCA then looked at this highest standa rd error, and used that standard error ( se ) and the mean of the original 157 data point sample to develop an additional 99% UPL. Becaus e of the large number of data points, this was calculated with a z-statistic, rather than the t-statistic used above. The z-statistic at α = 0.01 is 2.576.

This calculation is: Χ ത ൅ ሾ 2.576 ൈ ݏ݁ ሿ 

### . For the data from Arcelor, this is: 994.1 ൅ ሾ 2.576 ൈ 9.269 ሿ 

### , which results in a value of 1018.0.

The MPCA also looked at emissions information from th ree-hour compliance stack test s conducted from 2000 through 2009. These data further support the BART limit, as all would have demonstrated compliance wi th the limit established.

### Stack Test Date Furnace Average Emission Rate (lbs/hr)
June 2000 853 February 2001 537 January 2002 821
June 2003 726
June 2005 756
June 2007 762 March/April 2009 812

After reviewing stack test data provided by ArcelorMitta l, the MPCA has determined that an appropriate BART NO X 

### limit is 1018.0 lbs/hour. This limit is for all fo ur stacks from the indurating furnace co mbined, and is a 30-day rolling average.

Compliance is to be determined through NO X 

### performance testing, simultaneously measured for 30 hourly data points. The MPCA is requiring this longer stack testing in order to en sure that the sample is sufficiently representative and long enough to capture periods of both higher and lowe r emissions, in order to ensure compliance.Arcelor Mittal Mining - Data for NO X BART Limit on Indurating Furnaces

ID Timestamp NOx lbs/hour (Arcelor) NOx lbs/hour (MPCA) 1 3/12/08 0:3 0 1037.5 1037.4 Descriptive Statistics 2 3/12/08 1:3 0 1013.4 1013.2 Arcelor Data MPCA Data 3 3/12/08 2:3 0 1013.9 1013.7 Average 994.1 980.3 4 3/12/08 3:3 0 1026.6 1026.5 St Dev 31.2 50.6 5 3/12/08 4:3 0 1043.1 1042.9 Max 1060.5 1060.4 6 3/12/08 5:3 0 1048.8 1048.7 Min 909.4 732.1 7 3/12/08 6:30 1033.1 1033.0 t 0.05, c-1 1.975 1.975 8 3/12/08 7:3 0 1006.5 1006.4 UPL 95% 1006.405 1000.193 9 3/12/08 8:30 976.7 976.6 t 0.01, c-1 2.608 2.608 10 3/12/08 9:3 0 973.9 973.8 UPL 99% 1010.34 0 1006.57 4 11 3/12/08 10:3 0 1043.0 1042.9 12 3/12/08 11:3 0 1027.1 1026.9 13 3/12/08 12:3 0 1001.3 912.5 14 3/12/08 13:30 1001.1 838.9 Test Date and Time Stack and Run NO X Emission Rate, lbs/hr
15 3/12/08 14:3 0 983.7 983.5 June 200 0 Furnace Average 853.0 16 3/12/08 15:3 0 959.0 958.8 Stack A 17 3/12/08 16:3 0 953.0 952.8 06/27/01 0830-1015 Run 1 144.5 18 3/12/08 17:3 0 956.8 894.0 06/27/01 1105-1213 Run 2 145.3 19 3/13/08 0:3 0 991.4 991.2 06/27/01 1305-1412 Run 3 154.8 20 3/13/08 1:3 0 1019.4 1019.3 Stack B 21 3/13/08 2:3 0 1021.6 1021.4 06/27/01 0830-1015 Run 1 176.7 22 3/13/08 3:3 0 1006.8 1006.7 06/27/01 1105-1213 Run 2 213.8 23 3/13/08 4:3 0 986.7 986.6 06/27/01 1305-1412 Run 3 181.8 24 3/13/08 5:3 0 977.1 977.0 Stack C 25 3/13/08 6:3 0 926.2 926.1 06/27/01 0830-1015 Run 1 218.3 26 3/13/08 7:3 0 983.5 983.4 06/27/01 1105-1213 Run 2 218.5 27 3/13/08 8:3 0 998.7 998.6 06/27/01 1305-1412 Run 3 222.7 28 3/13/08 9:3 0 993.3 993.2 Stack D 29 3/13/08 10:3 0 964.6 964.5 06/27/01 0830-1015 Run 1 301.1 30 3/13/08 11:3 0 976.3 732.1 06/27/01 1105-1213 Run 2 283.4 31 3/13/08 12:3 0 995.2 995.0 06/27/01 1305-1412 Run 3 297.8 32 3/13/08 13:3 0 976.4 976.2 33 3/13/08 14:3 0 990.0 989.9 February 2001 Furnace Average 537.0 34 3/13/08 15:3 0 961.8 961.7 Stack A 35 3/13/08 16:3 0 975.5 975.3 02/15/01 0915-1015 Run 1 42.9 36 3/13/08 17:3 0 1032.5 1032.4 02/15/01 1030-1130 Run 2 33.0 37 3/13/08 18:3 0 1040.2 1036.8 02/15/01 1145-1245 Run 3 32.9 38 3/13/08 19:3 0 1040.2 1002.2 Stack B 39 3/13/08 20:3 0 1015.9 1012.4 02/15/01 0915-1015 Run 1 94.7 40 3/13/08 21:3 0 1007.4 1007.3 02/15/01 1030-1130 Run 2 60.6 41 3/13/08 22:3 0 1022.7 1022.5 02/15/01 1145-1245 Run 3 61.9 42 3/13/08 23:3 0 1060.5 1060.4 Stack C 43 3/14/08 0:3 0 1021.3 1021.2 02/15/01 0915-1015 Run 1 190.7 44 3/14/08 1 30 1002 5 1002 4 02/15/01 1030 1130 R 2 206 8 Supporting Data from Compliance Tests

44 3/ 14 /08

1: 30 1 002 .5 1 002 .4 02 / 15

/ 01 1030-1130 Run 2 206.8 45 3/14/08 2:3 0 1004.2 1004.1 02/15/01 1145-1245 Run 3 170.8 46 3/14/08 3:3 0 993.7 993.5 Stack D 47 3/14/08 4:3 0 975.4 975.3 02/15/01 0915-1015 Run 1 215.2 48 3/14/08 5:3 0 987.7 987.6 02/15/01 1030-1130 Run 2 244.9 49 3/14/08 6:3 0 1011.2 1011.0 02/15/01 1145-1245 Run 3 256.4 50 3/14/08 7:3 0 1035.7 948.1 51 3/14/08 8:3 0 1000.7 835.4 January 2002 Furnace Average 821 52 3/14/08 9:3 0 988.7 899.5 Stack A 53 3/14/08 10:3 0 935.2 935.0 1/23/2002 1040 - 1139 Run 1 109.1 54 3/14/08 11:3 0 977.9 977.8 1/23/2002 1147 - 1246 Run 2 110.0 55 3/14/08 18:4 5 958.1 958.0 1/23/2002 1255 - 1354 Run 3 116.2 56 3/14/08 19:4 5 976.3 976.2 Stack B 57 3/17/08 14:4 5 915.1 915.0 1/23/2002 0710 - 0809 Run 1 150.9 58 3/17/08 15:4 5 975.2 975.1 1/23/2002 0819 - 1918 Run 2 148.4 59 3/17/08 16:4 5 1042.3 1042.1 1/23/2002 0927 - 1026 Run 3 146.5 60 3/17/08 17:4 5 1037.9 1037.8 Stack C 61 3/17/08 18:4 5 1035.4 1035.3 1/22/2002 1320 - 1419 Run 1 224.9 62 3/17/08 19:4 5 1045.2 1045.1 1/22/2002 1428 - 1527 Run 2 222.3 63 3/17/08 20:4 5 986.7 960.4 1/22/2002 1534 - 1633 Run 3 233.1 64 3/18/08 10:4 5 1009.4 1053.9 Stack D 65 3/18/08 11:4 5 1043.1 1043.0 1/22/2002 0900 - 0959 Run 1 323.2 66 3/18/08 12:4 5 1028.2 1023.5 1/22/2002 1017 - 1116 Run 2 330.6 67 3/18/08 13:4 5 1054.0 1053.8 1/22/2002 1138 - 1237 Run 3 348.5 68 3/18/08 14:4 5 1037.8 1037.7 69 3/18/08 15:4 5 1001.1 1000.9 June 2003 Furnace Average 726 70 3/18/08 16:4 5 1004.9 1004.7 Stack A 71 3/18/08 17:4 5 1018.7 1018.5 6/24/2003 0810 - 0910 Run 1 110.2 72 3/18/08 18:4 5 913.4 832.0 6/24/2003 1330 - 1430 Run 2 116.7 73 3/18/08 19:4 5 909.4 909.3 6/24/2003 1450 - 1550 Run 3 112.1 74 3/18/08 20:4 5 950.5 950.4 Stack B 75 3/18/08 21:4 5 980.2 980.1 6/24/2003 0810 - 0910 Run 1 137.5 76 3/18/08 22:4 5 1007.8 1007.7 6/24/2003 1330 - 1430 Run 2 127.1 77 3/18/08 23:4 5 995.0 994.8 6/24/2003 1450 - 1550 Run 3 126.5 78 3/19/08 0:4 5 985.4 985.3 Stack C 79 3/19/08 1:4 5 1010.5 1010.4 6/24/2003 0810 - 0910 Run 1 189.8 80 3/19/08 2:4 5 1051.2 1051.1 6/24/2003 1330 - 1430 Run 2 190.8 81 3/19/08 3:4 5 1027.5 1027.3 6/24/2003 1450 - 1550 Run 3 199.1 82 3/19/08 4:4 5 1040.6 1040.5 Stack D 83 3/19/08 5:4 5 1006.7 1006.6 6/24/2003 0810 - 0910 Run 1 294.0 84 3/19/08 6:4 5 992.0 991.8 6/24/2003 1330 - 1430 Run 2 284.285 3/19/08 7:4 5 1019.0 863.8 6/24/2003 1450 - 1550 Run 3 289.6 86 3/19/08 8:4 5 998.2 900.7 87 3/19/08 9:4 5 974.2 942.1 June 2005 Furnace Average 756 88 3/19/08 10:4 5 980.4 980.2 Stack A 89 3/19/08 11:4 5 969.8 969.7 6/28/2005 0810 - 0910 Run 1 113.4 90 3/19/08 12:4 5 1026.0 1025.8 6/28/2005 0935 - 1035 Run 2 104.2 91 3/19/08 13:4 5 1020.9 1020.7 6/28/2008 1045 - 1145 Run 3 106.2 92 3/19/08 14:4 5 1014.8 1014.6 Stack B 93 3/19/08 15:4 5 1000.1 999.9 6/28/2005 1210 - 1310 Run 1 137.7 94 3/19/08 16:4 5 981.9 978.7 6/28/2005 1325 - 1425 Run 2 140.2 95 3/19/08 17:4 5 982.1 982.0 6/28/2005 1440 - 1540 Run 3 138.8 96 3/19/08 18:4 5 990.7 990.6 Stack C 97 3/19/08 19:4 5 1001.9 1001.8 6/29/2005 0750 - 0850 Run 1 221.5 98 3/19/08 20:4 5 995.1 995.0 6/29/2005 0905 -1005 Run 2 215.8 99 3/19/08 21:4 5 952.6 952.4 6/29/2005 1020 - 1120 Run 3 207.2 100 3/19/08 22:4 5 933.8 933.6 Stack D 101 3/19/08 23:4 5 932.2 898.5 6/29/2005 1140 - 1240 Run 1 293.6 102 3/20/08 0:4 5 997.8 997.6 6/29/2005 1255 - 1355 Run 2 303.3 103 3/20/08 1:4 5 1023.9 1023.8 6/29/2005 1410 - 1510 Run 3 301.1 104 3/20/08 2:4 5 1016.2 1016.0 105 3/20/08 3:4 5 987.4 987.2 June 2007 Furnace Average 762 106 3/20/08 4:4 5 978.6 978.5 Stack A 107 3/20/08 5:4 5 978.6 978.5 6/19/2007 0955 - 1104 Run 1 102.5 108 3/20/08 6:4 5 1021.6 1021.5 6/19/2007 1140 - 1253 Run 2 100.1 109 3/20/08 7:4 5 1017.0 861.4 6/19/2007 1322 - 1428 Run 3 100.7 110 3/20/08 8:4 5 1020.3 921.4 Stack B 111 3/20/08 9:4 5 1028.6 1028.5 6/19/2007 1504 - 1609 Run 1 127.5 112 3/20/08 10:4 5 995.8 995.6 6/19/2007 1635 - 1739 Run 2 131.7 113 3/20/08 11:4 5 976.2 976.0 6/19/2007 1800 - 1904 Run 3 130.8 114 3/20/08 12:4 5 1020.3 1020.2 Stack C 115 3/20/08 13:4 5 1031.6 1007.0 6/20/2007 0610 - 0715 Run 1 199.9 116 3/20/08 14:4 5 980.6 912.9 6/20/2007 0740 - 0845 Run 2 210.4 117 3/20/08 15:4 5 936.5 936.4 6/20/2007 0914 - 1014 Run 3 231.4 118 3/20/08 16:4 5 933.9 933.8 6/20/2007 1051 - 1154 Run 4 201.5 119 3/20/08 17:4 5 913.4 871.7 Stack D 120 3/20/08 18:4 5 931.0 903.9 6/20/2007 1305 - 1412 Run 1 268.4 121 3/20/08 19:4 5 963.8 936.5 6/20/2007 1444 - 1547 Run 2 270.4 122 3/20/08 20:4 5 983.9 983.8 6/20/2007 1612 - 1717 Run 3 276.9 123 3/20/08 21:4 5 966.2 966.1 124 3/20/08 22:4 5 978.1 978.0 March/April 200 9 Furnace Average 812 125 3/20/08 23:4 5 973.7 973.5 Stack A 126 3/21/08 0:4 5 976.0 975.8 3/31/2009 1015 Run 1 139.0 127 3/21/08 1:4 5 994.3 994.2 3/31/2009 1249 Run 2 148.0 128 3/21/08 2:4 5 1006.7 1006.5 4/1/2009 1248 Run 3 135.2 129 3/21/08 3:4 5 969.3 969.2 Stack B 130 3/21/08 4:4 5 1011.6 1011.4 4/1/2009 1435 Run 1 150.5 131 3/21/08 5:4 5 1005.4 1005.3 4/1/2009 1600 Run 2 152.0 132 3/21/08 6:4 5 957.8 957.7 4/1/2009 1704 Run 3 155.5 / / 133 3/21/08 7:4 5 1003.9 1003.8 Stack C 134 3/21/08 8:4 5 987.4 839.8 4/2/2009 829 Run 1 235.0 135 3/21/08 9:4 5 1008.3 907.8 4/2/2009 932 Run 2 231.6 136 3/21/08 10:4 5 991.0 961.3 4/2/2009 1100 Run 3 236.1 137 3/21/08 11:4 5 970.3 970.2 Stack D 138 3/21/08 12:4 5 979.2 979.1 4/2/2009 1249 Run 1 283.8 139 3/21/08 13:4 5 982.8 982.7 4/2/2009 1425 Run 2 281.0 140 3/21/08 14:4 5 945.6 945.5 4/2/2009 1500 Run 3 288.4 141 3/21/08 15:4 5 937.5 937.4 142 3/21/08 16:4 5 968.5 968.4 143 3/21/08 17:4 5 1010.9 1010.8 144 3/21/08 18:4 5 1004.3 1004.2 145 3/21/08 19:4 5 972.8 972.6 146 3/21/08 20:4 5 989.3 989.1 147 3/21/08 21:4 5 1006.4 1006.3 148 3/21/08 22:4 5 1010.0 1009.9 149 3/21/08 23:4 5 1003.5 1003.4 150 3/22/08 0:4 5 1000.3 1000.2 151 3/22/08 1:4 5 984.3 961.3 152 3/22/08 2:4 5 967.7 967.5 153 3/22/08 3:4 5 972.4 972.3 154 3/22/08 4:4 5 1002.0 1001.8 155 3/22/08 5:4 5 989.0 988.8 156 3/22/08 6:4 5 1011.3 1011.2 157 3/22/08 7:4 5 990.7 911.9

Note: Arcelor determined some data was invalid. The MPCA re-included this data in some calculations, but chose to set the BART limit based on the data determined to be valid by Arcelor. 1020 960 900 840 780 3 5

3 0

2 5

2 0

1 5

1 0

5

0

N O x , lb / h rFrequency Lo c 1 0 0 2
S c a le 3 6 .4 5 N 157 H is to g ra m o f N O x , lb / h r
S m a lle s t E x tre m e V a lu eDEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### December 2, 2011 Office Memorandum

TO: 

### AQD File No. 541 (Delta ID No. 13700061)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### Nitrogen Oxides BART Limits for Hibbing Taconite Company (HTC)

This memo was prepared to provide the documentation of the MPCA’s NO X 

### BART limit determination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information 1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address
P.O. Box 589 Hibbing, MN 55746 Highway 5 North, Fire Number 4590 Hibbing, MN 55746, St. Louis County Contact: Ms. Julie Lucas; Phone: (218) 262-6856

1.2 Description of the Facility

Hibbing Taconite Company (HTC) is a taconite (magnetite ) ore mining and beneficiation facility located in Hibbing, Minnesota. HTC is owned by ArcelorMitta l, Cliffs Natural Resources, and US St eel; Cliffs Natural Resources is the managing agent.

The major steps in taconite pellet production include ta conite ore mining, crushing, grinding, concentrating, agglomerating, and indurating. The larger sources of air emissions at HTC are from the mining activities and indurating furnace operations, with lesser amounts from other processing operations and fugitive dust sources, including haul roads and the tailings basin.

The facility was constructed in two ph ases. Phase I included two Dravo-Lurgi straight grate indurating furnaces. Construction of the phase began in 1974 and operation bega n in 1976. A third Dravo-Lurgi straight grate indurating furnace was added in Phase II. Construction of Phas e II began in 1976, with operation beginning in 1979.

The three pellet indurating furnaces are functionally equivalen t. The average production of the three furnaces is roughly equivalent. While the facility is capable of producing 9 m illion dry long tons annually, it reached its maximum in 1988 when it produced in excess of 8.6 million dry long tons . HTC’s pelletizing furnaces are currently controlled by wet scrubbers primarily to remove particulate matter.

HTC started operation in 1976 with the flexibility to use natu ral gas or fuel oil (all grades). All three furnaces started operation with fuel oil No. 6 (Bunker C) as the primary fuel and were then switched over to natural gas as the primary fuel during 1981. (In the recent pa st, the facility evaluated other fu els including wood and oat hulls.)

### 2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology available and associated emission reductio ns achievable. The analysis must take into consideration the techno logy available, the costs of compliance, th e energy and non-air quality environmental impacts, any pollution control equipment in use at the source , the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The units for which the MPCA must determine BART and establish a NO X 

### BART limit consistent with that determination

are:

Emission Unit Name EU Number Co ntrol Equipment and Stack Numbers Line 1 Pelletizing Furnace EU020 SV021, SV022, SV023, SV024 Line 2 Pelletizing Furnace EU021 SV025, SV026, SV027, SV028 Line 3 Pelletizing Furnace EU022 SV029, SV030, SV031, SV032

2.3 The BART Determination

The MPCA’s NO X 

### BART determination for this unit, as documented in Appendix 9.3 of the December 2009 Regional Haze SIP submittal, is good combustion prac tices and implementation of furnace ener gy efficiency projects in 2005 and 2006. However, due to the lack of sufficient emissions data repr esenting the range of operating conditions that influence emissions, the MPCA did not set an emission limit at the time of making the BART determination.

Instead, the MPCA and HTC entered into an Administrative Order, under which HTC provided additional NO X 

### emission information to the MPCA.

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NO X 

### emission information provided by HTC. Extensive stack tests were conducted using Method 7E. Initial stack tests were conducted in 2007 and 2008, and co vered the entire range of the plant’s operating conditions. Stack tests conducted in 2010 (July, October, November, Decemb er) were split to reflect the plant’s two main operating conditions: producing standard pellets and producing high compression pellets.

### Under the previously mentioned Administ rative Order, HTC was required to colle ct “a minimum of 150 one-hour data points under the range of [furnace] operating parameters that influence NO X 

### emissions. The range of each operating parameter during testing should be representative of furn ace’s operating range for the parameters in the 12 months previous to testing.” This requirement was to ensure that the emissions data collected wa s appropriately representative of the range of operating conditions for the furnace.

The data was collected through simultaneous testing of ea ch of the four furnace stacks at each furnace, and continuously measured data was used to calculate four 15-minute averages for each hour. Then, an hourly average level was calculated for each hour. The process of calculati ng the BART limit for HTC’s indurating furnaces began by constructing a 99% confidence interval and taking the upper predictive level. The MPCA believes the use of a 99% upper predictive level for setting the limit is appropriate, due to the need for limits to be met during all operating conditions, including during times of startup, shutdown, and malfunction.

The example calculation is below:

Mean of 30 data points ൌ Χ ത ൅ ሾݐ െ ݐݏܽݐ ൈ ߪ ൈ ඨ ሺ 1
30 ൅ 1

ݐ݊ݑ݋ܿ ሻሿ

• Where Χ ത and σ are, respectively, the mean and standard de viation of the sample of hourly-averaged NO X 

### data points;

• The t-stat is the 2-tail percentage point of the t-dist ribution with a level of significance of 0.01 and the appropriate degrees of freedom; and

• ට ሺ ଵ

ଷ଴ 

### ൅ ଵ

௖௢௨௡௧ 

### ሻ is used to relate the sample sizes for the intended compliance test and the sample data

set.

The table below shows the descriptive statistics for the samp le data. The MPCA’s review focused on the 2010 data. In addition, MPCA staff reviewed the earlier stack test data from 2007 and 2008, and looked at the difference in emissions between the furnaces, as the three furnaces are extremely similar.

Hibbing Taconite NO X 

### Stack Test Values (in lbs/hour)
Line 1 Line 2 Line 3 Standard High Comp Standard High Comp Standard High Comp 2007/2008 Tests
# Data Points 162 177 156
Mean 406.4 392.3 315.5
St Dev 39.00 60.10 39.54 Max Value 479.3 510.5 366.4 Min Value 321.9 268.2 113.1 2010 Stack Tests
# Data Points 198 190 162 179 193 178
Mean 376.1 428.0 546.0 711.5 285.7 326.3
St Dev 23.53 37.95 38.0 51.35 30.76 23.41 Max Value 423.2 470.8 630.7 765.2 310.6 355.8 Min Value 275.7 208.0 437.1 249.0 42.2 135.0 99% Interval UPL 388.1 447.4 565.7 737.8 301.4 338.3

### A review of the data showed that the data from Line 1 and Line 3 were relatively consistent through the two different tests, and that the data from these furnaces were relative ly similar to each other, as shown in the graph below.

However, as shown in the graph below, emissions from Line 2 were very different in the 2010 test from the previous 2007 test, and also appeared quite different from emissions from Lines 1 and 3.

Therefore, the MPCA took a much closer look at the data from Line 2. The combustion chambers on the furnaces at Hibbing Taconite have been modified to add a gas-fired burn er at the lower part of the chamber (a vertically placed cylindrical body; two chambers per furnace line). Although the original top burner remains to facilitate oil-firing in case of natural gas curtailment, the MPCA beli eves that using the lower burner is the main operating scenario. The benefit of

### using the lower burner, when firing with natural gas, is a slight fuel saving with an apparent reduction in NO X 

### formation and emissions. Based on the data, it appe ars that the two sets of data from Line 2 may result from different burner management or operation.

Because of the discrepancy in the data, the MPCA believes th at CEMS are necessary to moni tor emissions on Line 2 in order to most accurately characterize the emissions. However, the MPCA needs to set a BART limit at this time. Because the initial Line 2 data appears to be closer to a standard operating condition for these units, the MPCA chose to set the limit for Line 2 based on the 99% UPL of all data from Line 2 – both the 2007 and 2010 stack test data. Because Line 2 will eventually be using CEMs data fo r compliance, using the formula to relate the sample sizes for the intended compliance test and the sample data set includes a total of 720 data point for the intended compliance test – 30 days of 24 hourly data points. Also, because the sample size including all the data is large (over 300 data points) a z statistic was used rather than a t-statistic. The resulting equation is:

Mean of 720 data points ൌ Χ ത ൅ ሾݖ െ ݐݏܽݐ ൈ ߪ ൈ ඨ ሺ 1
720 ൅ 1

ݐ݊ݑ݋ܿ ሻሿ

After reviewing stack test data provided by HTC, the MPCA has determined that appropriate BART NO X 

### limits are:

Unit BART NO X 

### Limit (lbs/hr) Line 1 Indurating Furnace 447.4 Line 2 Indurating Furnace 571.7 Line 3 Indurating Furnace 338.3

These limits are a 30-day rolling average.

For Line 1 and Line 3, the MPCA conducted additional analysis in order to help alleviate conc erns that any one stack test, even an extended stack test, cannot capture all anticipated fu rnace operating conditions. This was done through the use of bootstrapping, a resampling technique designed to replicate the taking of multiple samples of the same size from a population.

This technique uses the sample data points as a representative population, from which multiple samples of 30 data points are drawn. A random number generator was used to sele ct the hourly data points used in constructing each 30 data point sample. A total of 2000 sets of 30 hourly data points were generated. The mean of each 30 point data set was then used to make a new, larger, sample of 2000 data points to represent the over all “population” of potential emission levels. This was repeated several times. Each of the surrogate populations thus created had a different standard error. Standard error is the standard deviation of a summary statistic, or a measure of the precision of the estimate. So, in essence, the variability of the standard error for each of these surrogate populations gives a sense of how much the sample mean may differ from the “true” or population mean. Th e MPCA then looked at this highest standard error, and used that standard error ( se ) and the mean of the original data point sa mple to develop an additional 99% UPL. The bootstrap analysis for each line resulted in very similar emission limits, so the MPCA chose to use the classic prediction method.

This limit is for all four stacks from each indurating furnace combined. Compliance is to be determined through NO X 

### stack testing, simultaneously measured fo r 30 hourly data points. Once CEMS are installed on Li ne 2, those monitors will be used for compliance. CEMS are to be installed and ce rtified within 14 months of the effective date of the Administrative Order implementing the BART limits.Hibbing Taconite - Data for NOx BART Limit on Indurating Furnaces Line 1 Line 2

Timestamp L1 NOx lb/hr - HC Pellets Timestamp L1 NOx lb/hr - Std Pellets Timestamp L2 NOx lb/hr - All Pellets 7/16/10 9:0 0 444.0 10/13/10 17:0 0 423.2 10/24/07 19:3 4 384.5 7/16/10 10:0 0 446.1 10/13/10 18:0 0 418.1 10/25/07 12:1 0 355.0 7/16/10 11:0 0 435.7 10/13/10 19:0 0 414.2 10/25/07 13:1 0 356.3 7/16/10 12:0 0 429.7 10/13/10 20:0 0 418.9 10/25/07 14:1 0 355.5 7/16/10 13:0 0 427.1 10/13/10 21:0 0 404.5 10/25/07 14:4 7 352.5 7/16/10 14:0 0 422.4 10/13/10 22:0 0 415.4 10/25/07 15:4 7 349.9 7/16/10 16:0 0 430.7 10/13/10 23:0 0 416.9 10/25/07 16:4 7 348.4 7/16/10 17:0 0 281.4 10/14/10 0:0 0 403.1 10/25/07 17:4 7 340.2 7/16/10 18:0 0 401.3 10/14/10 1:0 0 414.7 10/25/07 18:4 7 335.4 7/16/10 19:0 0 432.2 10/14/10 2:0 0 416.7 10/25/07 19:4 7 337.2 7/16/10 20:0 0 439.6 10/14/10 3:0 0 408.4 10/25/07 20:4 7 350.4 7/16/10 21:0 0 440.6 10/14/10 4:0 0 415.0 10/25/07 21:4 7 343.3 7/16/10 22:0 0 440.2 10/14/10 5:0 0 409.1 10/25/07 22:4 7 337.0 7/16/10 23:0 0 436.0 10/14/10 6:0 0 409.1 10/25/07 23:4 7 333.2 7/17/10 0:0 0 429.4 10/14/10 7:0 0 414.8 10/26/07 0:4 7 335.3 7/17/10 1:0 0 441.4 10/14/10 8:0 0 412.4 10/26/07 1:4 7 334.0 7/17/10 2:0 0 434.9 10/14/10 10:0 0 408.5 10/26/07 2:4 7 337.6 7/17/10 3:0 0 436.3 10/14/10 11:0 0 397.5 10/26/07 3:4 7 329.4 7/17/10 4:0 0 438.0 10/14/10 12:0 0 400.1 10/26/07 4:4 7 339.7 7/17/10 5:0 0 435.3 10/14/10 13:0 0 400.0 10/26/07 5:4 7 336.9 7/17/10 6:0 0 431.4 10/14/10 14:0 0 388.4 10/26/07 6:4 7 336.9 7/17/10 7:0 0 432.0 10/14/10 15:0 0 391.6 10/26/07 7:4 7 347.2 7/17/10 8:0 0 430.4 10/14/10 16:0 0 386.2 10/26/07 8:4 7 365.3 7/17/10 9:0 0 443.2 10/14/10 17:0 0 384.0 10/26/07 9:1 4 359.7 7/17/10 10:0 0 434.0 10/14/10 18:0 0 389.0 10/26/07 11:5 4 350.5 7/17/10 11:0 0 441.7 10/14/10 19:0 0 367.6 10/26/07 12:5 4 351.9 7/17/10 12:0 0 444.3 10/14/10 20:0 0 392.2 10/26/07 13:5 4 347.9 7/17/10 13:0 0 449.8 10/14/10 21:0 0 400.9 10/26/07 14:5 4 349.4 7/17/10 14:0 0 437.0 10/14/10 22:0 0 396.4 10/26/07 15:5 4 349.3 7/17/10 15:0 0 424.9 10/14/10 23:0 0 398.1 10/26/07 16:5 4 364.3 7/17/10 16:0 0 430.6 10/15/10 0:0 0 397.5 10/26/07 17:5 4 363.5 7/17/10 17 00 433 0 10/15/10 1 00 398 2 10/26/07 18 54 367 7 7/17/10 17:0 0 . 10/15/10 1:0 0 . 10/26/07 18:5 . 7/17/10 18:0 0 434.5 10/15/10 2:0 0 389.3 10/26/07 19:5 4 364.6 7/17/10 19:0 0 431.6 10/15/10 3:0 0 395.6 10/26/07 20:5 4 371.0 7/17/10 20:0 0 420.0 10/15/10 4:0 0 389.6 10/26/07 21:5 4 367.0 7/17/10 21:0 0 430.5 10/15/10 5:0 0 383.8 10/26/07 22:5 4 368.0 7/17/10 22:0 0 431.9 10/15/10 6:0 0 388.0 10/26/07 23:5 4 367.9 7/17/10 23:0 0 426.8 10/15/10 7:0 0 390.3 10/27/07 0:5 4 371.3 7/18/10 1:0 0 418.8 10/15/10 8:0 0 390.9 10/27/07 1:5 4 369.4 7/18/10 2:0 0 425.6 10/15/10 9:0 0 383.5 10/27/07 2:5 4 372.5 7/18/10 3:0 0 418.8 10/15/10 10:0 0 379.0 10/27/07 3:5 4 376.3 7/18/10 4:0 0 405.4 10/15/10 11:0 0 382.2 10/27/07 4:5 4 384.2 7/18/10 5:0 0 402.0 10/15/10 12:0 0 377.4 10/27/07 5:5 4 378.0 7/18/10 6:0 0 419.1 10/15/10 14:0 0 368.8 10/27/07 6:5 4 378.1 7/18/10 7:0 0 411.5 10/15/10 15:0 0 380.8 10/27/07 7:5 4 462.1 7/18/10 8:0 0 412.9 10/15/10 16:0 0 373.8 10/27/07 8:5 4 483.1 7/18/10 9:0 0 418.9 10/15/10 17:0 0 339.7 10/27/07 11:0 4 453.5 7/18/10 10:0 0 419.5 10/15/10 18:0 0 348.2 10/27/07 12:0 4 485.9 7/18/10 11:0 0 420.1 10/15/10 19:0 0 386.0 10/27/07 13:0 4 481.5 7/18/10 12:0 0 423.5 10/15/10 20:0 0 380.5 10/27/07 14:0 4 476.3 7/18/10 13:0 0 424.4 10/15/10 21:0 0 378.4 10/27/07 15:0 4 478.2 7/18/10 14:0 0 419.8 10/15/10 22:0 0 386.6 10/27/07 16:0 4 476.1 7/18/10 15:0 0 421.9 10/15/10 23:0 0 400.2 10/27/07 17:0 4 495.5 7/18/10 16:0 0 360.9 10/16/10 0:0 0 398.4 10/27/07 18:0 4 493.9 7/18/10 18:0 0 423.8 10/16/10 1:0 0 392.6 10/27/07 19:0 4 504.7 7/18/10 19:0 0 420.3 10/16/10 2:0 0 396.5 10/27/07 20:0 4 502.6 7/18/10 20:0 0 424.6 10/16/10 3:0 0 389.1 10/27/07 21:0 4 499.4 7/18/10 21:0 0 245.2 10/16/10 4:0 0 382.4 10/27/07 22:0 4 503.5 7/18/10 22:0 0 388.3 10/16/10 5:0 0 389.4 10/27/07 23:0 4 503.7 7/18/10 23:0 0 427.6 10/16/10 6:0 0 396.6 10/28/07 0:0 4 506.9 7/19/10 0:0 0 429.4 10/16/10 8:0 0 412.5 10/28/07 0:4 2 499.87/19/10 1:0 0 433.7 10/16/10 9:0 0 371.7 10/28/07 21:2 7 364.0 7/19/10 2:0 0 432.6 10/16/10 10:0 0 391.9 10/28/07 22:2 7 357.8 7/19/10 3:0 0 432.1 10/16/10 11:0 0 404.7 10/28/07 23:2 7 346.2 7/19/10 4:0 0 439.4 10/16/10 12:0 0 399.9 10/29/07 0:2 7 345.7 7/19/10 5:0 0 438.0 10/16/10 13:0 0 385.7 10/29/07 1:2 7 339.1 7/19/10 6:0 0 437.3 10/16/10 14:0 0 380.3 10/29/07 2:2 7 345.9 7/19/10 7:0 0 425.3 10/16/10 15:0 0 379.6 10/29/07 3:2 7 349.2 7/19/10 8:0 0 443.8 10/16/10 16:0 0 387.4 10/29/07 4:2 7 348.8 7/19/10 10:0 0 441.5 10/16/10 17:0 0 376.4 10/29/07 5:2 7 343.5 7/19/10 11:0 0 437.6 10/16/10 18:0 0 379.8 10/29/07 6:2 7 347.7 7/19/10 12:0 0 428.9 10/16/10 19:0 0 383.0 10/29/07 7:5 9 320.3 7/19/10 13:0 0 414.3 10/16/10 20:0 0 383.6 10/29/07 9:5 9 333.9 7/19/10 14:0 0 425.8 10/16/10 21:0 0 386.4 10/29/07 10:5 9 329.1 7/19/10 15:0 0 431.1 10/16/10 22:0 0 373.9 10/29/07 11:5 9 326.2 7/19/10 16:0 0 427.6 10/16/10 23:0 0 313.5 10/29/07 12:5 9 331.1 7/19/10 17:0 0 424.3 10/17/10 0:0 0 372.6 10/29/07 13:5 9 327.4 7/19/10 18:0 0 423.6 10/17/10 1:0 0 382.1 10/29/07 14:5 9 327.3 7/19/10 19:0 0 419.5 10/17/10 2:0 0 407.6 10/29/07 15:5 9 321.6 7/19/10 20:0 0 429.4 10/17/10 3:0 0 410.4 10/29/07 16:5 9 268.2 7/19/10 21:0 0 208.0 10/17/10 4:0 0 396.5 10/29/07 17:5 9 337.1 7/19/10 22:0 0 272.7 10/17/10 5:0 0 275.7 10/29/07 18:5 9 323.1 7/19/10 23:0 0 456.4 10/17/10 6:0 0 359.9 10/29/07 19:5 9 327.7 7/20/10 0:0 0 451.1 10/17/10 7:0 0 390.1 10/29/07 20:5 9 325.8 7/20/10 1:0 0 456.0 10/17/10 8:0 0 389.0 10/29/07 21:5 9 332.3 7/20/10 2:0 0 456.4 10/17/10 9:0 0 383.1 10/29/07 22:5 9 333.1 7/20/10 3:0 0 465.2 10/17/10 10:0 0 393.1 10/29/07 23:5 9 327.8 7/20/10 4:0 0 460.7 10/17/10 11:0 0 391.1 10/30/07 0:5 9 330.4 7/20/10 5:0 0 455.1 10/17/10 12:0 0 390.6 10/30/07 1:5 9 335.1 7/20/10 6:0 0 454.2 10/17/10 13:0 0 391.7 10/30/07 2:5 9 327.5 7/20/10 7:0 0 456.0 10/17/10 14:0 0 387.9 10/30/07 3:5 9 318.0 7/20/10 8:0 0 246.6 10/17/10 15:0 0 389.2 10/30/07 4:5 9 310.5 7/20/10 10:0 0 411.9 10/17/10 17:0 0 396.2 10/30/07 5:2 9 304.3 7/20/10 11:0 0 441.3 10/17/10 18:0 0 389.6 10/30/07 10:4 0 452.0 7/20/10 12:0 0 445.2 10/17/10 19:0 0 387.4 10/30/07 11:4 0 437.1 7/20/10 13:0 0 380.2 10/17/10 20:0 0 387.4 10/30/07 12:4 0 432.7 7/20/10 14:0 0 444.7 10/17/10 21:0 0 388.5 10/30/07 13:4 0 419.0 7/20/10 15 00 450 2 10/17/10 22 00 386 1 10/30/07 14 40 424 1 7/20/10 15:0 0 . 10/17/10 22:0 0 . 10/30/07 14:4 . 7/20/10 16:0 0 449.9 10/17/10 23:0 0 378.5 10/30/07 15:4 0 382.5 7/20/10 17:0 0 445.4 10/18/10 0:0 0 375.6 10/30/07 16:4 0 390.4 7/20/10 18:0 0 442.4 10/18/10 1:0 0 383.6 10/30/07 17:4 0 380.1 7/20/10 19:0 0 447.6 10/18/10 2:0 0 384.0 10/30/07 18:4 0 386.7 7/20/10 20:0 0 446.6 10/18/10 3:0 0 387.8 10/30/07 19:4 0 388.1 7/20/10 21:0 0 445.9 10/18/10 4:0 0 382.8 10/30/07 20:4 0 391.1 7/20/10 22:0 0 443.4 10/18/10 5:0 0 383.0 10/30/07 21:4 0 393.3 7/20/10 23:0 0 448.4 10/18/10 6:0 0 381.5 10/30/07 22:4 0 392.2 7/21/10 0:0 0 449.7 10/18/10 7:0 0 381.2 10/30/07 23:4 0 370.8 7/21/10 1:0 0 445.3 10/18/10 8:0 0 383.2 10/31/07 0:4 0 376.6 7/21/10 2:0 0 442.2 10/18/10 9:0 0 383.4 10/31/07 7:4 9 400.4 7/21/10 3:0 0 449.1 10/18/10 11:0 0 385.6 10/31/07 9:3 0 398.7 7/21/10 4:0 0 447.5 10/18/10 12:0 0 387.5 10/31/07 11:3 0 411.5 7/21/10 5:0 0 454.7 10/18/10 13:0 0 386.2 10/31/07 12:3 0 400.2 7/21/10 6:0 0 451.4 10/18/10 14:0 0 380.9 10/31/07 13:3 0 398.5 7/21/10 7:0 0 451.3 10/18/10 15:0 0 370.0 10/31/07 14:3 0 409.9 7/21/10 8:0 0 446.1 10/18/10 16:0 0 364.6 10/31/07 14:4 5 401.1 7/21/10 9:0 0 449.8 10/18/10 17:0 0 371.0 10/31/07 15:4 5 401.1 7/21/10 10:0 0 447.7 10/18/10 18:0 0 366.3 10/31/07 16:3 5 406.3 7/21/10 11:0 0 455.8 10/18/10 19:0 0 360.5 10/31/07 20:1 1 442.8 7/21/10 12:0 0 467.1 10/18/10 20:0 0 364.9 10/31/07 21:1 1 467.6 7/21/10 13:0 0 462.0 10/18/10 21:0 0 360.9 10/31/07 22:1 1 472.7 7/21/10 14:0 0 456.3 10/18/10 22:0 0 368.5 10/31/07 23:1 1 493.4 7/21/10 15:0 0 457.3 10/18/10 23:0 0 360.1 11/1/07 0:11 488.4 7/21/10 16:0 0 464.4 10/19/10 0:0 0 346.4 11/1/07 1:11 486.7 7/21/10 17:0 0 461.1 10/19/10 1:0 0 344.7 11/1/07 2:11 482.6 7/21/10 18:0 0 467.7 10/19/10 2:0 0 334.8 11/1/07 3:11 491.3 7/21/10 19:0 0 470.8 10/19/10 3:0 0 330.5 11/1/07 4:11 489.9 7/21/10 20:0 0 467.5 10/19/10 4:0 0 334.3 11/1/07 5:11 490.97/21/10 21:0 0 467.1 10/19/10 5:0 0 331.9 11/1/07 6:11 481.9 7/21/10 22:0 0 460.5 10/19/10 6:0 0 323.4 11/1/07 6:3 0 510.5 7/21/10 23:0 0 463.8 10/19/10 7:0 0 325.9 11/1/07 7:3 0 411.5 7/22/10 0:0 0 463.9 10/19/10 8:0 0 326.9 11/1/07 8:3 0 365.6 7/22/10 1:0 0 464.2 10/19/10 9:0 0 320.1 11/1/07 10:1 4 370.3 7/22/10 2:0 0 458.9 10/19/10 10:0 0 285.0 11/1/07 11:1 4 360.4 7/22/10 3:0 0 458.9 10/19/10 13:0 0 320.1 11/1/07 12:1 4 364.4 7/22/10 4:0 0 460.1 10/19/10 14:0 0 348.2 11/1/07 13:1 4 354.9 7/22/10 5:0 0 450.7 10/19/10 15:0 0 345.1 11/1/07 14:1 4 357.8 7/22/10 6:0 0 446.0 10/19/10 16:0 0 351.0 11/1/07 15:1 4 364.5 7/22/10 7:0 0 455.1 10/19/10 17:0 0 354.9 11/1/07 16:1 4 359.0 7/22/10 8:0 0 456.7 10/19/10 18:0 0 355.4 11/1/07 17:1 4 362.8 7/22/10 9:0 0 450.3 10/19/10 19:0 0 359.7 11/1/07 18:1 4 364.5 7/22/10 10:0 0 447.1 10/19/10 20:0 0 361.0 11/1/07 19:1 4 381.7 7/22/10 11:0 0 445.3 10/19/10 21:0 0 353.4 11/1/07 20:1 4 406.0 7/22/10 12:0 0 448.0 10/19/10 22:0 0 368.1 11/1/07 21:1 4 434.4 7/22/10 13:0 0 446.2 10/19/10 23:0 0 359.8 11/1/07 22:1 4 444.7 7/22/10 14:0 0 446.5 10/20/10 0:0 0 357.3 11/1/07 23:1 4 436.8 7/22/10 15:0 0 444.0 10/20/10 1:0 0 361.4 11/2/07 0:1 4 441.6 7/22/10 16:0 0 444.1 10/20/10 2:0 0 360.6 11/2/07 1:1 4 446.1 7/22/10 17:0 0 443.6 10/20/10 3:0 0 359.3 11/2/07 2:1 4 412.5 7/22/10 18:0 0 449.5 10/20/10 4:0 0 352.5 11/2/07 3:1 4 407.2 7/22/10 19:0 0 446.6 10/20/10 5:0 0 349.3 11/2/07 4:1 4 441.3 7/22/10 20:0 0 435.2 10/20/10 6:0 0 350.6 11/2/07 5:1 4 430.8 7/22/10 21:0 0 373.0 10/20/10 7:0 0 353.2 11/2/07 6:1 4 433.2 7/22/10 22:0 0 439.6 10/20/10 8:0 0 365.3 11/2/07 7:1 4 413.0 7/22/10 23:0 0 436.1 10/20/10 10:0 0 375.6 11/2/07 7:29 314.3 7/23/10 0:0 0 431.5 10/20/10 11:0 0 376.5 11/2/07 8:0 0 318.5 7/23/10 1:0 0 432.6 10/20/10 12:0 0 378.1 11/2/07 9:35 319.2 7/23/10 2:0 0 440.4 10/20/10 13:0 0 382.3 11/2/07 10:35 314.6 7/23/10 3:0 0 439.4 10/20/10 14:0 0 364.3 11/2/07 11:35 320.7 7/23/10 4:0 0 424.4 10/20/10 15:0 0 366.3 11/2/07 12:35 320.0 7/23/10 5:0 0 235.8 10/20/10 16:0 0 373.9 11/2/07 13:35 328.3 7/23/10 6:0 0 422.5 10/20/10 17:0 0 376.0 11/2/07 14:35 322.9 7/23/10 7:0 0 440.6 10/20/10 18:0 0 377.9 11/2/07 14:5 9 329.6 7/23/10 8:0 0 438.4 10/20/10 19:0 0 373.6 11/2/07 15:5 9 458.6 7/23/10 9 00 435 0 10/20/10 20 00 381 5 11/2/07 16 29 476 4 7/23/10 9:0 0 . 10/20/10 20:0 0 . 11/2/07 16:2 . 7/23/10 10:0 0 422.3 10/20/10 21:0 0 370.2 11/2/07 17:2 9 464.1 7/23/10 11:0 0 410.5 10/20/10 22:0 0 364.9 11/2/07 18:2 9 477.6 7/23/10 12:0 0 418.3 10/20/10 23:0 0 368.2 11/2/07 19:2 9 474.3 7/23/10 13:0 0 417.8 10/21/10 0:0 0 367.5 11/2/07 20:2 9 462.0 7/23/10 14:0 0 414.2 10/21/10 1:0 0 365.0 11/2/07 21:2 9 472.0 7/23/10 15:0 0 407.7 10/21/10 2:0 0 368.3 11/2/07 22:2 9 472.0 7/23/10 16:0 0 392.3 10/21/10 3:0 0 361.4 11/2/07 23:2 9 454.0 7/23/10 17:0 0 400.5 10/21/10 4:0 0 382.9 11/3/07 0:29 469.9 7/23/10 18:0 0 408.0 10/21/10 5:0 0 388.2 11/3/07 1:29 473.1 7/23/10 19:0 0 407.3 10/21/10 6:0 0 388.8 11/3/07 2:29 465.3 7/23/10 20:0 0 421.2 10/21/10 7:0 0 384.7 11/3/07 3:29 468.0 7/23/10 21:0 0 413.0 10/21/10 8:0 0 385.4 11/3/07 4:29 458.0 7/23/10 22:0 0 416.6 10/21/10 9:0 0 376.9 11/3/07 5:29 473.5 7/23/10 23:0 0 412.5 10/21/10 10:0 0 369.8 7/24/10 0:0 0 411.1 10/21/10 12:0 0 359.6 7/24/10 1:0 0 403.0 10/21/10 13:0 0 359.3 7/24/10 2:0 0 406.5 10/21/10 14:0 0 366.2 7/24/10 3:0 0 410.8 10/21/10 15:0 0 362.4 7/24/10 4:0 0 410.5 10/21/10 16:0 0 362.6 7/24/10 5:0 0 404.0 10/21/10 17:0 0 370.0 7/24/10 6:0 0 409.3 10/21/10 18:0 0 368.5 7/24/10 7:0 0 402.1 10/21/10 19:0 0 364.6 7/24/10 8:0 0 397.7 10/21/10 20:0 0 365.3 7/24/10 9:0 0 402.1 10/21/10 21:0 0 364.5 7/24/10 10:0 0 409.9 10/21/10 22:0 0 358.3 7/24/10 11:0 0 408.3 10/21/10 23:0 0 362.3 10/22/10 0:0 0 351.7 10/22/10 1:0 0 357.6 10/22/10 2:0 0 346.910/22/10 3:0 0 351.6 10/22/10 4:0 0 347.6 10/22/10 5:0 0 349.8 10/22/10 6:0 0 352.7 10/22/10 7:0 0 351.7 Count 190 Count 198 Count 177 Average 428.02 Average 376.10 Average 392.32

St Dev 37.95 St Dev 23.53 St Dev 60.10

Max 470.8 4 Max 423.20 Max 510.49 Min 207.96 Min 275.72 Min 268.19
t 0.05, c-1 1.973 t 0.05, c-1 1.972 t 0.05, c-1 1.974 UPL 95% 442.73 UPL 95% 385.19 UPL 95% 415.7 4 UCL 95% 433.45 UCL 95% 379.40 UCL 95% 401.2 4
t 0.01, c-1 2.602 t 0.01, c-1 2.601 t 0.01, c-1 2.604 UPL 99% 447.42 UPL 99% 388.09 UPL 99% 423.22 UCL 99% 435.18 UCL 99% 380.45 UCL 99% 404.09Line 3

Timestamp Line 2 NOx lb/hr - Std Pellets Timestamp L2 NOx lb/hr - HC Pellets Timestamp L3 NOx lb/hr - HC Pellets Timestamp L3 NOx lb/hr - Std Pellets 10/22/10 17:0 0 607.7 11/6/10 15:0 0 741.8 11/16/10 13:0 0 324.1 11/27/10 13:0 0 294.01 10/22/10 18:0 0 610.0 11/6/10 16:0 0 755.8 11/16/10 14:0 0 318.3 11/27/10 14:0 0 295.70 10/22/10 19:0 0 586.3 11/6/10 17:0 0 763.4 11/16/10 15:0 0 318.2 11/27/10 15:0 0 301.17 10/22/10 20:0 0 618.8 11/6/10 18:0 0 760.1 11/16/10 16:0 0 316.6 11/27/10 16:0 0 300.9 4 10/22/10 21:0 0 628.1 11/6/10 19:0 0 765.2 11/16/10 17:0 0 319.0 11/27/10 17:0 0 301.50 10/22/10 22:0 0 601.8 11/6/10 20:0 0 760.5 11/16/10 18:0 0 320.1 11/27/10 18:0 0 302.76 10/22/10 23:0 0 599.0 11/6/10 21:0 0 745.4 11/16/10 19:0 0 317.5 11/27/10 19:0 0 299.37 10/23/10 0:0 0 602.0 11/6/10 22:0 0 746.3 11/16/10 20:0 0 315.4 11/27/10 20:0 0 298.86 10/23/10 1:0 0 594.2 11/6/10 23:0 0 759.8 11/16/10 21:0 0 317.8 11/27/10 21:0 0 298.83 10/23/10 2:0 0 589.4 11/7/10 0:0 0 738.3 11/16/10 22:0 0 326.7 11/27/10 22:0 0 297.09 10/23/10 3:0 0 590.2 11/7/10 1:0 0 741.3 11/16/10 23:0 0 327.7 11/27/10 23:0 0 298.86 10/23/10 4:0 0 618.4 11/7/10 2:0 0 745.2 11/17/10 0:0 0 332.5 11/28/10 0:0 0 297.00 10/23/10 5:0 0 612.4 11/7/10 3:0 0 756.0 11/17/10 1:0 0 332.9 11/28/10 1:0 0 294.28 10/23/10 12:0 0 557.9 11/7/10 4:0 0 751.1 11/17/10 2:0 0 333.8 11/28/10 2:0 0 293.72 10/23/10 13:0 0 566.5 11/7/10 5:0 0 746.3 11/17/10 3:0 0 332.2 11/28/10 3:0 0 294.03 10/23/10 14:0 0 579.2 11/7/10 6:0 0 750.4 11/17/10 4:0 0 335.3 11/28/10 4:0 0 294.99 10/23/10 15:0 0 572.2 11/7/10 7:0 0 756.4 11/17/10 5:0 0 336.4 11/28/10 5:0 0 291.93 10/23/10 16:0 0 571.3 11/7/10 8:0 0 749.9 11/17/10 6:0 0 333.8 11/28/10 6:0 0 294.31 10/23/10 17:0 0 571.0 11/7/10 9:0 0 755.0 11/17/10 7:0 0 336.2 11/28/10 7:0 0 293.42 10/23/10 18:0 0 553.6 11/7/10 10:0 0 753.1 11/17/10 8:0 0 333.2 11/28/10 8:0 0 293.49 10/23/10 19:0 0 561.6 11/7/10 11:0 0 740.4 11/17/10 9:0 0 341.8 11/28/10 9:0 0 291.37 10/23/10 20:0 0 579.4 11/7/10 12:0 0 737.1 11/17/10 10:0 0 336.0 11/28/10 10:0 0 290.46 10/23/10 21:0 0 572.4 11/7/10 13:0 0 740.2 11/17/10 11:0 0 336.0 11/28/10 11:0 0 289.10 10/23/10 22:0 0 555.2 11/7/10 14:0 0 744.7 11/17/10 12:0 0 336.6 11/28/10 12:0 0 290.27 10/23/10 23:0 0 575.5 11/7/10 15:0 0 748.2 11/17/10 13:0 0 322.8 11/28/10 14:0 0 284.77 10/24/10 0:0 0 547.2 11/7/10 16:0 0 740.1 11/17/10 14:0 0 306.8 11/28/10 15:0 0 277.78 10/24/10 1:0 0 550.5 11/7/10 17:0 0 744.2 11/17/10 15:0 0 324.1 11/28/10 16:0 0 292.63 10/24/10 2:0 0 550.6 11/7/10 18:0 0 748.4 11/17/10 16:0 0 328.6 11/28/10 17:0 0 294.2 4 10/24/10 3:0 0 551.9 11/7/10 19:0 0 741.0 11/17/10 17:0 0 297.1 11/28/10 18:0 0 294.31 10/24/10 4:0 0 572.1 11/7/10 20:0 0 732.0 11/17/10 18:0 0 309.7 11/28/10 19:0 0 294.50 10/24/10 5:0 0 568.6 11/7/10 21:0 0 728.7 11/17/10 19:0 0 325.7 11/28/10 20:0 0 292.53 10/24/10 6 00 566 7 11/7/10 22 00 732 1 11/17/10 20 00 329 2 11/28/10 21 00 290 94 10/24/10 6:0 0 . 11/7/10 22:0 . 11/17/10 20:0 . 11/28/10 21:0 . 10/24/10 7:0 0 565.8 11/7/10 23:0 0 737.1 11/17/10 21:0 0 328.4 11/28/10 22:0 0 286.85 10/24/10 8:0 0 569.4 11/8/10 0:0 0 722.3 11/17/10 22:0 0 330.0 11/28/10 23:0 0 289.0 4 10/24/10 9:0 0 558.1 11/8/10 1:0 0 737.4 11/17/10 23:0 0 331.5 11/29/10 0:0 0 287.60 10/24/10 10:0 0 558.2 11/8/10 2:0 0 728.2 11/18/10 0:0 0 327.9 11/29/10 1:0 0 287.98 10/24/10 11:0 0 563.7 11/8/10 3:0 0 727.5 11/18/10 1:0 0 327.7 11/29/10 2:0 0 289.12 10/24/10 12:0 0 560.5 11/8/10 4:0 0 729.5 11/18/10 2:0 0 327.4 11/29/10 3:0 0 290.45 10/24/10 13:0 0 557.5 11/8/10 5:0 0 733.5 11/18/10 3:0 0 328.3 11/29/10 4:0 0 290.20 10/24/10 15:0 0 550.3 11/8/10 6:0 0 729.5 11/18/10 4:0 0 331.6 11/29/10 5:0 0 290.79 10/24/10 16:0 0 553.4 11/8/10 7:0 0 726.8 11/18/10 5:0 0 331.0 11/29/10 6:0 0 292.4 4 10/24/10 17:0 0 554.7 11/8/10 8:0 0 733.0 11/18/10 6:0 0 330.9 11/29/10 7:0 0 293.19 10/24/10 18:0 0 551.6 11/8/10 9:0 0 738.8 11/18/10 7:0 0 328.9 11/29/10 8:0 0 293.17 10/24/10 19:0 0 554.1 11/8/10 11:0 0 726.8 11/18/10 8:0 0 330.6 11/29/10 9:0 0 294.6 4 10/24/10 20:0 0 561.3 11/8/10 12:0 0 675.8 11/18/10 9:0 0 331.6 11/29/10 10:0 0 293.10 10/24/10 21:0 0 561.5 11/8/10 13:0 0 644.6 11/18/10 10:0 0 331.6 11/29/10 11:0 0 291.23 10/24/10 22:0 0 560.1 11/8/10 14:0 0 651.9 11/18/10 11:0 0 334.6 11/29/10 12:0 0 288.11 10/24/10 23:0 0 555.8 11/8/10 15:0 0 654.8 11/18/10 12:0 0 333.5 11/29/10 13:0 0 290.12 10/25/10 0:0 0 561.9 11/8/10 16:0 0 657.6 11/18/10 13:0 0 335.8 11/29/10 14:0 0 290.06 10/25/10 1:0 0 557.6 11/8/10 17:0 0 663.5 11/18/10 14:0 0 327.0 11/29/10 15:0 0 289.88 10/25/10 2:0 0 557.0 11/8/10 18:0 0 687.4 11/18/10 15:0 0 328.8 11/29/10 16:0 0 288.08 10/25/10 3:0 0 553.0 11/8/10 19:0 0 683.2 11/18/10 16:0 0 327.3 11/29/10 17:0 0 287.28 10/25/10 4:0 0 557.6 11/8/10 20:0 0 711.0 11/18/10 17:0 0 326.9 11/29/10 18:0 0 286.60 10/25/10 5:0 0 560.5 11/8/10 21:0 0 710.5 11/18/10 18:0 0 327.3 11/29/10 19:0 0 285.79 10/25/10 6:0 0 557.7 11/8/10 22:0 0 720.2 11/18/10 19:0 0 319.6 11/29/10 20:0 0 284.26 10/25/10 7:0 0 556.9 11/8/10 23:0 0 728.3 11/19/10 11:0 0 316.8 11/29/10 21:0 0 282.00 10/25/10 8:0 0 554.9 11/9/10 0:0 0 658.6 11/19/10 12:0 0 321.2 11/30/10 10:0 0 240.81 10/25/10 9:0 0 534.1 11/9/10 1:0 0 659.2 11/19/10 14:0 0 327.8 11/30/10 11:0 0 75.10 10/25/10 18:0 0 564.7 11/9/10 2:0 0 650.6 11/19/10 15:0 0 332.0 11/30/10 12:0 0 152.92 10/25/10 19:0 0 550.8 11/9/10 3:0 0 653.0 11/19/10 16:0 0 331.5 11/30/10 13:0 0 258.28 10/25/10 20:0 0 553.6 11/9/10 4:0 0 653.0 11/19/10 17:0 0 334.3 11/30/10 14:0 0 259.6910/25/10 21:0 0 551.0 11/9/10 5:0 0 648.6 11/19/10 18:0 0 333.3 11/30/10 15:0 0 264.81 10/25/10 22:0 0 552.1 11/9/10 6:0 0 655.7 11/19/10 19:0 0 329.3 11/30/10 16:0 0 267.36 10/25/10 23:0 0 551.3 11/9/10 7:0 0 649.0 11/19/10 20:0 0 328.1 11/30/10 17:0 0 274.66 10/26/10 0:0 0 542.7 11/9/10 8:0 0 660.1 11/19/10 21:0 0 328.4 11/30/10 18:0 0 280.10 10/26/10 1:0 0 542.0 11/9/10 9:0 0 662.3 11/19/10 22:0 0 328.9 11/30/10 19:0 0 283.13 10/26/10 2:0 0 530.0 11/9/10 11:0 0 724.5 11/19/10 23:0 0 333.9 11/30/10 20:0 0 284.76 10/26/10 3:0 0 528.8 11/9/10 12:0 0 721.7 11/20/10 0:0 0 333.4 11/30/10 21:0 0 287.89 10/26/10 4:0 0 524.3 11/9/10 13:0 0 719.1 11/20/10 1:0 0 329.8 11/30/10 22:0 0 287.80 10/26/10 12:0 0 506.6 11/9/10 14:0 0 708.0 11/20/10 2:0 0 333.2 11/30/10 23:0 0 286.0 4 10/26/10 13:0 0 512.6 11/9/10 15:0 0 715.4 11/20/10 3:0 0 326.7 12/1/10 0:0 0 284.30 10/26/10 14:0 0 558.1 11/9/10 16:0 0 709.1 11/20/10 4:0 0 330.6 12/1/10 1:0 0 284.50 10/26/10 15:0 0 573.7 11/9/10 17:0 0 709.8 11/20/10 5:0 0 331.1 12/1/10 2:0 0 288.79 10/26/10 16:0 0 563.7 11/9/10 18:0 0 707.6 11/20/10 6:0 0 336.0 12/1/10 3:0 0 294.38 10/26/10 17:0 0 564.4 11/9/10 19:0 0 636.1 11/20/10 7:0 0 335.1 12/1/10 4:0 0 294.33 10/26/10 18:0 0 549.4 11/9/10 20:0 0 617.6 11/20/10 8:0 0 333.6 12/1/10 5:0 0 295.61 10/26/10 19:0 0 559.3 11/9/10 21:0 0 714.1 11/20/10 9:0 0 340.3 12/1/10 6:0 0 295.98 10/26/10 20:0 0 570.5 11/9/10 22:0 0 713.3 11/20/10 10:0 0 342.6 12/1/10 7:0 0 295.42 10/26/10 21:0 0 555.1 11/9/10 23:0 0 709.9 11/20/10 11:0 0 342.2 12/1/10 8:0 0 295.07 10/26/10 22:0 0 547.7 11/10/10 0:0 0 716.0 11/20/10 12:0 0 342.2 12/1/10 9:0 0 297.87 10/26/10 23:0 0 562.6 11/10/10 1:0 0 723.0 11/20/10 13:0 0 349.6 12/1/10 10:0 0 297.95 10/27/10 0:0 0 567.8 11/10/10 2:0 0 714.9 11/20/10 14:0 0 350.8 12/1/10 11:0 0 300.92 10/27/10 1:0 0 565.3 11/10/10 3:0 0 725.0 11/20/10 15:0 0 332.9 12/1/10 12:0 0 296.96 10/27/10 2:0 0 573.0 11/10/10 4:0 0 726.5 11/20/10 16:0 0 321.0 12/1/10 13:0 0 298.10 10/27/10 3:0 0 568.5 11/10/10 5:0 0 728.1 11/20/10 17:0 0 351.1 12/1/10 14:0 0 296.08 10/27/10 4:0 0 583.7 11/10/10 6:0 0 724.8 11/20/10 18:0 0 346.3 12/1/10 15:0 0 294.52 10/27/10 5:0 0 573.1 11/10/10 7:0 0 724.3 11/20/10 19:0 0 349.4 12/1/10 16:0 0 294.70 10/27/10 6:0 0 564.8 11/10/10 8:0 0 721.5 11/20/10 20:0 0 348.9 12/1/10 17:0 0 296.88 10/27/10 7:0 0 562.8 11/10/10 9:0 0 719.8 11/20/10 21:0 0 346.3 12/1/10 18:0 0 300.85 10/27/10 8:0 0 558.4 11/10/10 10:0 0 704.2 11/20/10 22:0 0 348.7 12/1/10 19:0 0 299.29 10/27/10 9:0 0 559.2 11/10/10 11:0 0 694.8 11/20/10 23:0 0 349.0 12/1/10 20:0 0 299.19 10/27/10 10:0 0 561.2 11/10/10 12:0 0 692.4 11/21/10 0:0 0 349.1 12/1/10 21:0 0 300.2 4 10/27/10 11:0 0 562.5 11/10/10 13:0 0 695.5 11/21/10 1:0 0 348.5 12/1/10 22:0 0 298.89 10/27/10 12:0 0 545.7 11/10/10 14:0 0 692.5 11/21/10 2:0 0 349.9 12/1/10 23:0 0 301.31 10/27/10 13:0 0 540.4 11/10/10 15:0 0 692.0 11/21/10 3:0 0 354.4 12/2/10 0:0 0 301.31 10/27/10 14:0 0 543.7 11/10/10 16:0 0 707.1 11/21/10 4:0 0 355.8 12/2/10 1:0 0 299.72 10/27/10 15:0 0 538.5 11/10/10 17:0 0 717.3 11/21/10 5:0 0 352.5 12/2/10 2:0 0 297.82 10/27/10 16 00 529 4 11/10/10 18 00 722 6 11/21/10 6 00 350 8 12/2/10 3 00 295 79 10/27/10 16:0 0 . 11/10/10 18:0 . 11/21/10 6:0 . 12/2/10 3:0 . 10/27/10 17:0 0 526.6 11/10/10 19:0 0 705.5 11/21/10 7:0 0 348.6 12/2/10 4:0 0 299.70 10/27/10 18:0 0 537.0 11/10/10 20:0 0 707.6 11/21/10 8:0 0 350.4 12/2/10 5:0 0 267.51 10/27/10 19:0 0 531.5 11/10/10 21:0 0 716.6 11/21/10 9:0 0 353.4 12/2/10 6:0 0 226.65 10/27/10 20:0 0 531.7 11/10/10 22:0 0 714.1 11/21/10 10:0 0 351.2 12/2/10 7:0 0 196.9 4 10/27/10 21:0 0 521.3 11/10/10 23:0 0 713.3 11/21/10 11:0 0 347.4 12/2/10 8:0 0 131.39 10/27/10 22:0 0 520.6 11/11/10 0:0 0 713.2 11/21/10 12:0 0 347.6 12/2/10 9:0 0 273.71 10/27/10 23:0 0 522.0 11/11/10 1:0 0 711.4 11/21/10 13:0 0 348.7 12/2/10 10:0 0 281.69 10/28/10 0:0 0 517.2 11/11/10 2:0 0 705.9 11/21/10 15:0 0 342.9 12/2/10 11:0 0 42.20 10/28/10 1:0 0 513.8 11/11/10 3:0 0 711.6 11/21/10 16:0 0 340.2 12/2/10 12:0 0 207.76 10/28/10 2:0 0 512.3 11/11/10 4:0 0 720.1 11/21/10 17:0 0 334.7 12/2/10 13:0 0 275.18 10/28/10 3:0 0 509.9 11/11/10 5:0 0 726.8 11/21/10 18:0 0 337.0 12/2/10 14:0 0 288.46 10/28/10 4:0 0 504.8 11/11/10 6:0 0 739.4 11/21/10 19:0 0 333.9 12/2/10 15:0 0 287.37 10/28/10 5:0 0 515.4 11/11/10 7:0 0 740.5 11/21/10 20:0 0 331.2 12/2/10 16:0 0 283.87 10/28/10 6:0 0 510.5 11/11/10 8:0 0 749.8 11/22/10 15:0 0 135.0 12/2/10 17:0 0 283.11 10/28/10 7:0 0 497.1 11/11/10 9:0 0 745.3 11/22/10 16:0 0 257.9 12/2/10 18:0 0 281.75 10/28/10 8:0 0 496.4 11/11/10 10:0 0 753.0 11/22/10 17:0 0 262.0 12/2/10 19:0 0 284.70 10/28/10 9:0 0 494.4 11/11/10 11:0 0 743.5 11/22/10 18:0 0 279.5 12/2/10 20:0 0 286.48 10/28/10 10:0 0 511.1 11/11/10 12:0 0 681.0 11/22/10 19:0 0 274.9 12/2/10 21:0 0 288.06 10/28/10 11:0 0 515.0 11/11/10 13:0 0 733.3 11/22/10 20:0 0 286.2 12/2/10 22:0 0 288.30 10/28/10 12:0 0 526.3 11/11/10 14:0 0 723.9 11/22/10 21:0 0 284.0 12/2/10 23:0 0 287.67 10/28/10 13:0 0 515.4 11/11/10 15:0 0 724.3 11/22/10 22:0 0 284.5 12/3/10 0:0 0 288.41 10/28/10 14:0 0 522.9 11/11/10 16:0 0 717.8 11/22/10 23:0 0 285.1 12/3/10 1:0 0 289.28 10/28/10 15:0 0 516.0 11/11/10 17:0 0 660.5 11/23/10 0:0 0 287.6 12/3/10 2:0 0 288.28 10/28/10 16:0 0 509.8 11/11/10 18:0 0 724.3 11/23/10 1:0 0 283.9 12/3/10 3:0 0 290.1 4 10/28/10 17:0 0 509.0 11/11/10 19:0 0 724.1 11/23/10 2:0 0 283.9 12/3/10 4:0 0 288.62 10/28/10 18:0 0 497.0 11/11/10 20:0 0 720.2 11/23/10 3:0 0 288.8 12/3/10 5:0 0 292.51 10/28/10 19:0 0 488.3 11/11/10 21:0 0 710.1 11/23/10 4:0 0 288.0 12/3/10 6:0 0 291.40 10/28/10 20:0 0 498.9 11/11/10 22:0 0 718.2 11/23/10 5:0 0 291.0 12/3/10 7:0 0 292.85 10/28/10 21:0 0 489.8 11/11/10 23:0 0 714.6 11/23/10 6:0 0 289.2 12/3/10 8:0 0 292.4910/28/10 22:0 0 489.9 11/12/10 0:0 0 717.1 11/23/10 7:0 0 287.4 12/3/10 9:0 0 288.90 10/28/10 23:0 0 496.3 11/12/10 12:0 0 748.1 11/23/10 8:0 0 265.8 12/3/10 10:0 0 284.46 10/29/10 0:0 0 492.5 11/12/10 13:0 0 749.3 11/23/10 9:0 0 285.1 12/3/10 11:0 0 286.67 10/29/10 1:0 0 479.1 11/12/10 14:0 0 740.6 11/23/10 10:0 0 293.0 12/3/10 12:0 0 289.03 10/29/10 2:0 0 476.1 11/12/10 15:0 0 612.3 11/23/10 11:0 0 322.2 12/3/10 13:0 0 292.2 4 10/29/10 3:0 0 472.3 11/12/10 16:0 0 249.0 11/23/10 12:0 0 319.6 12/3/10 14:0 0 292.57 10/29/10 4:0 0 475.6 11/12/10 17:0 0 390.3 11/23/10 13:0 0 325.9 12/3/10 15:0 0 295.21 10/29/10 5:0 0 476.6 11/12/10 18:0 0 676.1 11/23/10 14:0 0 325.1 12/3/10 16:0 0 297.02 10/29/10 6:0 0 452.3 11/12/10 19:0 0 729.2 11/23/10 15:0 0 327.6 12/3/10 17:0 0 299.08 10/29/10 7:0 0 496.1 11/12/10 20:0 0 717.0 11/23/10 16:0 0 331.7 12/3/10 18:0 0 295.49 10/29/10 8:0 0 515.0 11/12/10 21:0 0 720.0 11/23/10 17:0 0 331.3 12/3/10 19:0 0 286.90 10/29/10 9:0 0 572.2 11/12/10 22:0 0 717.7 11/23/10 18:0 0 327.6 12/3/10 20:0 0 285.47 10/29/10 10:0 0 604.4 11/12/10 23:0 0 723.4 11/23/10 19:0 0 327.9 12/3/10 21:0 0 293.06 10/29/10 12:0 0 607.4 11/13/10 0:0 0 728.6 11/23/10 20:0 0 326.7 12/3/10 22:0 0 293.72 10/29/10 13:0 0 630.7 11/13/10 1:0 0 729.1 11/23/10 21:0 0 333.0 12/3/10 23:0 0 291.79 10/29/10 14:0 0 496.8 11/13/10 2:0 0 725.0 11/23/10 22:0 0 332.7 12/4/10 0:0 0 297.06 10/29/10 15:0 0 548.3 11/13/10 3:0 0 724.1 11/23/10 23:0 0 334.3 12/4/10 1:0 0 291.40 10/29/10 16:0 0 457.0 11/13/10 4:0 0 719.3 11/24/10 0:0 0 332.8 12/4/10 15:0 0 295.32 10/29/10 17:0 0 452.6 11/13/10 5:0 0 728.1 11/24/10 1:0 0 333.6 12/4/10 16:0 0 294.17 10/29/10 18:0 0 443.4 11/13/10 6:0 0 734.5 11/24/10 2:0 0 338.3 12/4/10 17:0 0 284.49 10/29/10 19:0 0 437.1 11/13/10 7:0 0 728.4 11/24/10 3:0 0 335.3 12/4/10 18:0 0 291.56 10/29/10 20:0 0 446.0 11/13/10 8:0 0 723.7 11/24/10 4:0 0 338.3 12/4/10 19:0 0 298.66 10/29/10 21:0 0 509.5 11/13/10 9:0 0 729.2 11/24/10 5:0 0 336.0 12/4/10 20:0 0 296.42 10/29/10 22:0 0 587.4 11/13/10 10:0 0 724.3 11/24/10 6:0 0 333.4 12/4/10 21:0 0 286.80 10/29/10 23:0 0 583.6 11/13/10 11:0 0 735.6 11/24/10 7:0 0 336.4 12/4/10 22:0 0 279.65 10/30/10 0:0 0 572.1 11/13/10 12:0 0 746.3 11/24/10 8:0 0 333.3 12/4/10 23:0 0 290.35 10/30/10 1:0 0 562.2 11/13/10 13:0 0 691.8 11/24/10 9:0 0 331.5 12/5/10 0:0 0 283.03 10/30/10 2:0 0 557.9 11/13/10 14:0 0 711.1 11/24/10 10:0 0 330.3 12/5/10 1:0 0 289.45 10/30/10 3:0 0 560.3 11/13/10 15:0 0 711.9 11/24/10 11:0 0 333.1 12/5/10 2:0 0 289.76 10/30/10 4:0 0 564.7 11/13/10 16:0 0 710.0 11/24/10 12:0 0 331.1 12/5/10 3:0 0 290.60 10/30/10 5:0 0 563.1 11/13/10 17:0 0 712.7 11/24/10 13:0 0 326.3 12/5/10 4:0 0 292.30 10/30/10 6:0 0 565.4 11/13/10 19:0 0 708.5 11/24/10 14:0 0 327.3 12/5/10 5:0 0 289.77 10/30/10 7:0 0 579.2 11/13/10 20:0 0 708.5 11/24/10 15:0 0 326.8 12/5/10 6:0 0 291.29 10/30/10 8:0 0 596.1 11/13/10 21:0 0 714.0 11/24/10 16:0 0 326.6 12/5/10 7:0 0 289.20 10/30/10 9:0 0 585.8 11/13/10 22:0 0 705.2 11/24/10 17:0 0 325.6 12/5/10 8:0 0 298.59 11/13/10 23:0 0 710.1 11/24/10 18:0 0 322.9 12/5/10 9:0 0 298.98 11/14/10 0 00 694 3 11/24/10 19 00 324 0 12/5/10 10 00 293 04 11/14/10 0:0 0 . 11/24/10 19:0 . 12/5/10 10:0 . 11/14/10 1:0 0 709.1 11/24/10 20:0 0 328.0 12/5/10 11:0 0 288.4 4 11/14/10 2:0 0 701.8 11/24/10 21:0 0 327.6 12/5/10 12:0 0 297.17 11/14/10 3:0 0 714.4 11/24/10 22:0 0 329.0 12/5/10 13:0 0 297.72 11/14/10 4:0 0 705.4 11/24/10 23:0 0 331.1 12/5/10 14:0 0 291.15 11/14/10 5:0 0 709.8 11/25/10 0:0 0 331.0 12/5/10 15:0 0 292.23 11/14/10 6:0 0 709.2 11/25/10 1:0 0 331.4 12/5/10 16:0 0 290.92 11/14/10 7:0 0 707.5 11/25/10 2:0 0 331.6 12/5/10 17:0 0 292.91 11/14/10 8:0 0 700.4 11/25/10 3:0 0 332.6 12/5/10 18:0 0 292.11 11/14/10 9:0 0 707.5 11/25/10 4:0 0 332.6 12/5/10 19:0 0 290.62 11/14/10 10:0 0 725.1 11/25/10 5:0 0 337.0 12/5/10 20:0 0 294.1 4 11/14/10 11:0 0 704.7 11/25/10 6:0 0 339.2 12/5/10 21:0 0 294.32 11/14/10 12:0 0 705.3 11/25/10 7:0 0 339.0 12/5/10 22:0 0 294.48 11/14/10 13:0 0 719.5 11/25/10 8:0 0 342.4 12/5/10 23:0 0 293.22 11/14/10 14:0 0 726.0 11/25/10 9:0 0 334.1 12/6/10 0:0 0 291.59 11/14/10 15:0 0 716.2 12/6/10 1:0 0 292.75 12/6/10 2:0 0 294.70 12/6/10 3:0 0 288.93 12/6/10 4:0 0 290.03 12/6/10 5:0 0 279.35 12/6/10 6:0 0 272.97 12/6/10 7:0 0 282.02 12/6/10 8:0 0 290.52 12/6/10 9:0 0 306.58 12/6/10 10:0 0 310.61 12/6/10 11:0 0 276.40 12/6/10 12:0 0 306.05 12/6/10 13:0 0 307.32 12/6/10 14:0 0 307.39 12/6/10 15:0 0 309.6 4Count 162 Count 179 Count 178 Count 193 Average 545.98 Average 711.46 Average 326.25 Average 285.69

St Dev 38.04 St Dev 51.35 St Dev 23.41 St Dev 30.76

Max 630.71 Max 765.15 Max 355.76 Max 310.61 Min 437.07 Min 249.01 Min 134.97 Min 42.20
t 0.05, c-1 1.975 t 0.05, c-1 1.973 t 0.05, c-1 1.973 t 0.05, c-1 1.972 UPL 95% 560.91 UPL 95% 731.46 UPL 95% 335.37 UPL 95% 297.59 UCL 95% 551.88 UCL 95% 719.0 4 UCL 95% 329.71 UCL 95% 290.05
t 0.01, c-1 2.607 t 0.01, c-1 2.604 t 0.01, c-1 2.604 t 0.01, c-1 2.603 UPL 99% 565.69 UPL 99% 737.8 4 UPL 99% 338.28 UPL 99% 301.40 UCL 99% 553.77 UCL 99% 721.46 UCL 99% 330.82 UCL 99% 291.45

### Line 1 Bootstrap Information

Classic prediction interval calculation for 30 new data points Mean Stdev Count alpha 2-tail t upper level 428.0 37.95 190 0.01 2.602 447.4 0.05 1.973 442.7

Bootstrap results with 2000 replicates Tool Mean SE(ave30) alpha 2-tail z upper level
Excel 2007 428.0 6.891 0.01 2.576 445.8 0.05 1.960 441.5Line 2 InformationBART Limit Options1) Using L2S and L2H Data (2010)Use of the 2-tail 99% confidence level for the fitted normal patternMean 632.82-tail z0.012.576 2-tail 99% UCL646.0Stdev 94.422-tail z0.051.960 2-tail 95% UCL642.9Count 3412) Using the combined L2P, L2S, and L2H DataMean 550.72-tail 99% UCL566.7Stdev 141.92-tail 95% UCL562.9Count 518For predicting the next single data point2-tail 99% UPL916.52-tail 95% UPL829.0For predicting the next 30 data points - representing a 30 data point stack test2-tail 99% UPL619.32-tail 95% UPL602.9For predicting the next 720 data points - representing 30-day rolling average from daily hourly CEMS measurements.2-tail 99% UPL571.72-tail 95% UPL566.7Line 3 Bootstrap Information

Classic prediction interval calculation for 30 new data points Mean Stdev Count alpha 2-tail t upper level 326.3 23.41 178 0.01 2.604 338.3 0.05 1.973 335.4

Bootstrap results with 2000 replicates Tool Mean SE(ave30) alpha 2-tail z upper level
Excel 2007 326.3 4.252 0.01 2.576 337.2 0.05 1.960 334.6DEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### November 30, 2011 Office Memorandum

TO: 

### AQD File No. 27A (Delta ID No. 07500003)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### Nitrogen Oxides BART Limits for Northshore Mining Company (NSM)

This memo was prepared to provide the documentation of the MPCA’s NO X 

### BART limit determination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information

1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address Northshore Mining Company
10 Outer Drive Silver Bay, MN 55614 Northshore Mining Company
10 Outer Drive Silver Bay, MN 55614, Lake County
Contact: Mr. Scott Gisc hia; Phone: (218) 226-6076

1.2 Description of the Facility

Northshore Mining Company’s (NSM) Silver Bay facility is located on the north sh ore of Lake Superior. It was the first taconite operation in Minnesota, originally built in the mid-1950s by Reserve Mining Company. Cleveland Cliffs, Incorporated purchased the fac ility from Cyprus Minerals in 1994; Clevela nd Cliffs now owns and operates the facility.

NSM has four indurating furnaces. Furnaces 11 and 12 bega n operating in 1963, a few years after Furnaces 5 and 6 started operation. However, Furnace 5 was shut down for several years; in 2006, NSM received a Prevention of Significant Deterioration permit authorizing the restarting of Furnace 5. Furnaces 11 and 12 were manufactured by Arthur G. McKee and are NSM’s largest indurating furnaces. They each burn a maximum of 150 MMBtu/hr of natural gas and are capable of processing 300 tons of pellets per hour.

NSM also operates two process boilers th at are subject to BART. Both process boilers were installed in 1965 and are rated at 79 MMBtu/hr. The boilers are capable of burning fuel oil and natural gas.

### 2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology available and associated emission reductio ns achievable. The analysis must take into consideration the techno logy available, the costs of compliance, th e energy and non-air quality environmental impacts, any pollution control equipment in use at the source , the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The units for which the MPCA must determine BART and establish a NO X 

### BART limit consistent with that determination
is:

Emission Unit Name EU Number Co ntrol Equipment and Stack Numbers Indurating Furnace #11 – Hood Exhaust EU100 SV101, SV102, SV103 Indurating Furnace #11 – Waste Gas EU104 SV104, SV105 Indurating Furnace #12 – Hood Exhaust EU110 SV111, SV112, SV113 Indurating Furnace #12 – Waste Gas EU114 SV114, SV115 Process Boiler #1 EU003 SV003 Process Boiler #2 EU004 SV003

2.3 The BART Determination

The MPCA’s NO X 

### BART determinations for these units are documented in Appendix 9.3 of the December 2009 Regional Haze SIP submittal. The BART NO X 

### determination for the process boilers is existing design and permitted fuels. The BART
NO X 

### determination for the indurating furnaces is good combustion practices.

However, due to the lack of sufficient emissions data repr esenting the range of operating conditions that influence emissions, the MPCA did not set an emission limit at the time of making the BART determination for the indurating furnaces. Instead, the MPCA and NSM entered into an Admi nistrative Order, under which NSM provided additional NO X 

### emission information to the MPCA.

### 2.4 MPCA Determination of the BART Limit

The BART limit for the process boilers was previously determined and is 0.17 lbs NO X 

### /MMBtu heat input; no SO 2 

### limit was set as the process boilers burn only natural gas and low sulfur distillate fuel oil. The SO 2 

### BART limit for the furnaces was previously determined and is 0.0651 lb SO2 per long ton of pellets fired (finished) that applies only when the company is burning natural gas.

The MPCA reviewed the NO X 

### emission information from the indurating furnaces provided by NSM. Under the previously mentioned Administrative Order, NSM wa s required to collect “a minimum of 150 one-hour data points under the range of [furnace] operating parameters that influence NO X 

### emissions. The range of each operating parameter during testing should be representative of furnace’s operating range for th e parameters in the 12 months previous to testing.” This requirement was to ensure that the emissions data collected was appropriately representative of the range of operating conditions for the furnace. Method 7E stack tests were conducted in April and May 2008 and July 2009. The 2008 tests collected over 150 data points for each furnace, wh ile the 2009 tests were shorter (30 data points).

The BART limit, in the form of a mass emission rate of NO X 

### in lbs/hour for each furnace, was developed based on the 2008 data, with the 2009 data used to ch eck and further support the limit.

The data was analyzed to determine different limits that would be appropriate based on different compliance test durations. The MPCA believes the most appropriate compliance test would involve obtaining at least 30 hourly-averaged data points, as obtained by NSM in the 2009 stack testing. Using 30 data points also tends to reduce data fluctuations.

The process of calculating the BART limit for Furnace 11 began by constructing a 99% confidence interval and taking the upper prediction level. The MPCA believes the use of a 99% upper predictive level for setting the limit is appropriate, due to the need for limits to be met during all operating conditions, including during times of startup, shutdown, and malfunction.

The sample calculation below is for the 99% confidence interval:

Mean of 30 data points ൌ Χ ത ൅ ሾ2.604 ൈ ߪ ഥ ൈ ඨ ሺ 1
30 ൅ 1
176 ሻሿ

• Where Χ ത and ߪത are, respectively, the mean and standard de viation of the sample of 176 hourly-averaged
NO X 

### data points of 2008 for Furnace 11;

• The value 2.604 is the 2-tail percentage point of the t-distribution with a level of significance of 0.01 and 175 degrees of freedom;

• ට ሺ ଵ

ଷ଴ 

### ൅ ଵ

ଵ଻଺ 

### ሻ is used to relate the sample sizes for the intended compliance test and the 2008 Furnace 11
data set; and

• The resultant value is the recommended limit as the mean of 30 hourly-averaged data points.

### Northshore Mining NO X 

### Stack Test Values (in lbs/hour)

Furnace 11 Furnace 12 May 2008 Stack Test
# Data Points 176 158
Mean 111.0 98.9
St Dev 8.7 10.3 Max Value 130.4 130.0 Min Value 73.5 87.5 99% Interval UPL 115.9 115.8 July 2009 Stack Tests
# Data Points 35 32
Mean 94.0 90.1
St Dev 3.8 2.5 Max Value 102.0 95.5 Min Value 87.8 85.4 99% Interval UPL 93.85 87.6

The MPCA conducted additional analysis in order to help alle viate concerns that any one stack test, even an extended stack test, cannot capture all of the anticipated furnace operating conditions. This was done through the use of bootstrapping, a resampling technique designed to replicate the taking of multiple samples of the same size from a population.

This technique uses the data points from the 150 hour (or greater) stack test as a representative population, from what multiple samples of 30 data points are drawn. A random numb er generator was used to select the hourly data points used in constructing each 30 data point sample. A total of 2000 sets of 30 hourly data points were generated. The mean of each 30 point data set was then us ed to make a new, larger , sample of 2000 data points to represent the overall “population” of potential emission levels. This was repeated several times, both in Exce l and using the R statistical package.

Each of the surrogate populations thus cr eated had a different standard error. St andard error is the standard deviation of a summary statistic, or a measure of the precision of the estimate. So, in essence, the variability of the standard error for each of these surrogate populations gives a sense of how much the sample mean may differ from the “true” or population mean. In the bootstrapping technique, the standard error of datasets of 30 points drawn the new surrogate population (built from the mean of ea ch of 2000 randomly selected 30 data po int sample sets) ranged from 1.563 to 1.616 for Furnace 11 and from 1.883 to 1.896 for Furnace 12 .

The MPCA then looked at the analyses with varying standard error, and used that standard error ( se ) and the mean of the original data point sample to develop additional 99% UP Ls. Because of the large number of data points, this was calculated with a z-statistic, rather than th e t-statistic used above. The z-statistic at α = 0.01 is 2.576. This calculation is:
Χ ത ൅ ሾ 2.576 ൈ ݏ݁ ሿ . For the data from Nortshore, this is: 110.0 ൅ ሾ 2.576 ൈ 9.269 ሿ

.

Using the different standard errors, the 99% UPLs for Line 11 are all around 115 lbs/hour. The 99% UPLs for Northshore are all around 103 to 104 lbs/hour. Based on the MPCA’s experience in analyzing da ta from these units, the recommended limit for Furnace 12 is the sa me as that for Furnace 11, although completing the calculation shown above would result in a slightly lower value for Furnace 12.

### After reviewing stack test data provided by NSM, the MPCA has determined that an appropriate BART NO X 

### limit is that derived from the standard 99% UPL. This limit is supported by the bootstrap analysis. Therefore, the BART limit for Northshore is 115.5 lbs/hour per furnace; this limit is a 30-day rolling average.

Compliance is to be determined through NO X 

### performance testing, simultaneously measured from all five furnace stacks at each of the two furnaces for 30 hourly data points.Northshore Mining Company - Data for NOX BART Limit on Indurating FurnacesLine 11 Furnace - Combined StacksLine 12 Furnace - Combined StacksDescriptive StatisticsDate and TimeTotal EmissionRate, lb/hr Date/TimeTotal EmissionRate, lb/hrDate and TimeTotal Emission Rate,lb/hrDate/TimeTotal EmissionRate, lb/hrFurnace 112008 20095/15/08 0:00 104.2 07/27/09 19:00 91.84/22/08 20:00118.207/29/09 10:00 94.4 Average Emissions, lbs/hour111.1 94.05/15/08 1:00 103.1 07/27/09 20:00 87.84/22/08 21:00125.107/29/09 11:00 91.4 Stdev8.7 3.85/15/08 2:00 100.2 07/27/09 21:00 95.24/22/08 22:00125.807/29/09 12:00 91.8 Count176 355/15/08 3:00 110.0 07/27/09 22:00 95.94/22/08 23:00126.707/29/09 13:00 92.1 Maximum lbs/hour130.4 102.05/15/08 4:00 111.0 07/27/09 23:00 97.04/23/08 0:00127.107/29/09 14:00 95.5 Minimum lbs/hour73.5 87.85/15/08 5:00 110.2 07/28/09 00:00 100.04/23/08 1:00128.007/29/09 15:00 89.9t0.05, C-11.974 2.0325/15/08 6:00 113.5 07/28/09 01:00 99.64/23/08 2:00128.107/29/09 16:00 92.0 95% UPL114.46 95.925/15/08 7:00 113.5 07/28/09 02:00 94.64/23/08 3:00127.207/29/09 17:00 92.8t0.01, c-12.604 2.7285/15/08 8:00 113.1 07/28/09 04:004/23/08 4:00126.907/29/09 18:00 90.5 99% UPL115.97 93.855/15/08 9:00 100.6 07/28/09 05:00 90.84/23/08 5:00128.307/29/09 19:00 90.35/15/08 10:00 116.4 07/28/09 06:00 92.24/23/08 6:00130.107/29/09 20:00 94.05/15/08 11:00 117.2 07/28/09 07:00 90.44/23/08 7:00129.407/29/09 21:00 89.5Furnace 122008 20095/15/08 12:00 113.2 07/28/09 08:00 95.24/23/08 8:00119.407/29/09 22:00 91.0 Average Emissions, lbs/hour98.9 90.15/15/08 13:00 108.9 07/28/09 09:00 91.6 4/23/08 9:00 118.0 07/29/09 23:00 94.3 Stdev 10.3 2.55/15/08 14:00 107.1 07/28/09 10:00 93.3 4/23/08 10:00 117.2 07/30/09 00:00 89.2 Count 158 325/15/08 15:00 106.5 07/28/09 11:00 99.4 4/23/08 11:00 117.0 07/30/09 01:00 88.8 Maximum lbs/hour 130.0 95.55/15/08 16:00 109.0 07/28/09 12:00 95.1 4/23/08 12:00 117.0 07/30/09 02:00 89.1 Minimum lbs/hour 87.5 85.45/15/08 17:00 108.0 07/28/09 13:00 92.0 4/23/08 13:00 105.7 07/30/09 03:00 89.4t0.05, C-11.975 2.0405/15/08 18:00 104.6 07/28/09 14:00 89.74/23/08 14:00102.207/30/09 04:00 90.0 95% UPL114.49 91.405/15/08 19:00 105.5 07/28/09 15:00 93.14/23/08 15:0098.107/30/09 05:00 90.2t0.01, c-12.608 2.7445/15/08 20:00 108.8 07/28/09 16:00 90.04/23/08 16:0096.307/30/09 06:00 88.9 99% UPL115.86 87.625/15/08 21:00 106.9 07/28/09 17:00 89.84/23/08 17:0092.807/30/09 07:00 86.35/15/08 22:00 110.6 07/28/09 18:00 88.14/23/08 18:0091.907/30/09 08:00 90.05/15/08 23:00 103.0 07/28/09 19:00 91.34/23/08 19:0095.007/30/09 09:00 91.0All Data Combined5/16/08 0:00 94.807/28/09 20:00 93.24/23/08 20:0098.107/30/09 10:00 89.3 Average Emissions, lbs/hour103.15/16/08 1:00 96.407/28/09 21:00 89.34/23/08 21:0096.807/30/09 11:00 87.8 Stdev11.55/16/08 2:00 97.207/28/09 22:00 90.54/23/08 22:0093.807/30/09 12:00 85.7 Count4015/16/08 3:00 98.307/28/09 23:00 91.74/23/08 23:0096.407/30/09 13:00 89.7 Maximum lbs/hour130.45/16/08 4:00 108.8 07/29/09 00:00 93.64/24/08 0:0094.607/30/09 14:00 88.4 Minimum lbs/hour73.55/16/08 5:00 109.9 07/29/09 01:00 94.04/24/08 1:0093.407/30/09 15:00 85.8t0.05, C-15/16/08 6:00 113.2 07/29/09 02:00 98.64/24/08 2:0092.807/30/09 16:00 87.3/ // // // /2008 Stack Testing2009 Stack Testing2008 Stack Testing2009 Stack Testing5/16/08 7:00 101.6 07/29/09 03:00 102.04/24/08 3:0092.307/30/09 17:00 85.45/16/08 8:00 98.707/29/09 04:00 97.34/24/08 4:0092.35/16/08 9:00 101.3 07/29/09 05:00 98.64/24/08 5:0092.95/16/08 10:00 103.2 07/29/09 06:00 101.44/24/08 6:0091.35/16/08 11:00 99.295.54/24/08 7:0087.65/16/08 12:00 99.64/24/08 8:0091.75/16/08 13:00 106.74/24/08 9:0090.25/16/08 14:00 106.94/24/08 10:0089.65/16/08 15:00 109.54/24/08 11:0089.85/16/08 16:00 110.34/24/08 12:0088.15/16/08 17:00 111.24/24/08 13:0093.05/16/08 18:00 115.54/24/08 14:0090.65/16/08 19:00 113.44/24/08 15:0089.95/16/08 20:00 118.14/24/08 16:0093.65/16/08 21:00 124.24/24/08 17:0093.75/16/08 22:00 118.04/24/08 18:0092.95/16/08 23:00 125.24/24/08 19:0088.75/17/08 0:00 129.54/24/08 20:0088.45/17/08 1:00 130.44/24/08 21:0089.55/17/08 2:00 129.74/24/08 22:0088.55/17/08 3:00 129.24/24/08 23:0091.25/17/08 4:00 123.44/25/08 0:0091.25/17/08 5:00 119.94/25/08 1:0092.95/17/08 6:00 116.64/25/08 2:0095.35/17/08 7:00 112.04/25/08 3:0093.25/17/08 8:00 112.04/25/08 4:0091.35/17/08 9:00 110.24/25/08 5:0088.35/17/08 10:00 108.74/25/08 6:0093.75/17/08 11:00 108.64/25/08 7:0092.45/17/08 12:00 110.94/25/08 8:0093.25/17/08 13:00 108.74/25/08 9:0094.15/17/08 14:00 104.54/25/08 10:0090.05/17/08 15:00 104.14/25/08 11:0087.85/17/08 16:00 100.14/25/08 12:0088.75/17/08 17:00 101.14/25/08 13:0089.95/17/08 18:00 103.04/25/08 14:0088.55/17/08 19:00 106.04/25/08 15:0088.15/17/08 20:00 106.54/25/08 16:0089.75/17/08 21:00 105.74/25/08 17:0088.55/17/08 22:00 107.44/25/08 18:0089.75/17/08 23:00 103.64/25/08 19:0089.65/18/08 0:00 103.34/25/08 20:0089.35/18/08 1:00 103.54/25/08 21:0089.25/18/08 2:00 103.84/25/08 22:0087.65/18/08 3:00 103.34/25/08 23:0087.85/18/08 4:00 105.94/26/08 0:0088.25/18/08 5:00 114.34/26/08 1:0091.95/18/08 6:00 112.64/26/08 2:0089.95/18/08 7:00 97.54/26/08 3:0090.35/18/08 8:00 98.24/26/08 4:0092.75/18/08 9:00 108.04/26/08 5:0092.45/18/08 10:00 107.14/26/08 6:0090.65/18/08 11:00 106.84/26/08 7:0089.95/18/08 12:00 107.74/26/08 8:0091.75/18/08 13:00 110.84/26/08 9:0093.85/18/08 14:00 110.24/26/08 10:0094.55/18/08 15:00 106.34/26/08 11:0092.55/18/08 16:00 110.34/26/08 12:0091.05/18/08 17:00 113.14/26/08 13:0091.25/18/08 18:00 117.94/26/08 14:0097.95/18/08 19:00 118.34/26/08 15:0098.95/18/08 20:00 120.54/26/08 16:0098.75/18/08 21:00 120.24/26/08 17:0099.75/18/08 22:00 111.64/26/08 18:0099.85/18/08 23:00 107.94/26/08 19:00100.8/19/08 0 0010 24/26/08 20 001005/19/08 0:00 107.24/26/08 20:00.55/19/08 1:00 106.14/26/08 21:00101.95/19/08 2:00 111.94/26/08 22:00103.55/19/08 3:00 109.44/26/08 23:00105.45/19/08 4:00 112.24/27/08 0:00104.35/19/08 5:00 116.94/27/08 1:00104.35/19/08 6:00 107.64/27/08 2:00105.05/19/08 7:00 102.14/27/08 3:00104.75/19/08 8:00 104.24/27/08 4:00102.55/19/08 9:00 106.54/27/08 5:00103.25/19/08 10:00 110.04/27/08 6:00102.35/19/08 11:00 110.74/27/08 7:0098.05/19/08 12:00 112.34/27/08 8:0098.25/19/08 13:00 115.34/27/08 9:0097.35/19/08 14:00 126.24/27/08 10:0098.35/19/08 15:00 126.74/27/08 11:0096.65/19/08 16:00 126.44/27/08 12:0097.45/19/08 17:00 125.74/27/08 13:0099.65/19/08 18:00 125.54/27/08 14:0098.95/19/08 19:00 126.74/27/08 15:0099.45/19/08 20:00 129.34/27/08 16:0099.35/19/08 21:00 128.04/27/08 17:0098.65/19/08 22:00 117.64/27/08 18:0098.65/19/08 23:00 120.54/27/08 19:0099.15/20/08 0:00 121.64/27/08 20:00100.05/20/08 1:00 120.04/27/08 21:00102.25/20/08 2:00 118.74/27/08 22:00106.15/20/08 3:00 119.84/27/08 23:00105.45/20/08 4:00 118.04/28/08 0:00107.05/20/08 5:00 120.84/28/08 1:00106.75/20/08 6:00 114.54/28/08 2:00106.85/20/08 7:00 73.64/28/08 3:00106.35/20/08 8:00 96.14/28/08 4:00106.75/20/08 9:00 94.74/28/08 5:00104.15/20/08 10:00 90.64/28/08 6:00103.75/20/08 11:00 102.74/28/08 7:00103.25/20/08 12:00 102.14/28/08 8:00100.85/20/08 13:00 103.94/28/08 9:00100.85/20/08 14:00 104.44/28/08 10:00101.55/20/08 15:00 104.84/28/08 11:0099.45/20/08 16:00 105.64/28/08 12:00100.15/20/08 17:00 105.54/28/08 13:00103.05/20/08 18:00 107.94/28/08 14:00101.75/20/08 19:00 105.94/28/08 15:00102.15/20/08 20:00 104.94/28/08 16:00100.25/20/08 21:00 107.24/28/08 17:00101.05/20/08 22:00 107.04/28/08 18:0099.25/20/08 23:00 109.64/28/08 19:0099.15/21/08 0:00 113.04/28/08 20:0099.35/21/08 1:00 120.64/28/08 21:0098.85/21/08 2:00 120.64/28/08 22:0098.05/21/08 3:00 122.54/28/08 23:00100.45/21/08 4:00 118.44/29/08 0:0071.85/21/08 5:00 117.84/29/08 1:003.15/21/08 6:00 121.24/29/08 2:0045.65/21/08 7:00 123.94/29/08 3:0085.95/21/08 8:00 116.44/29/08 4:0097.85/21/08 9:00 119.04/29/08 5:0097.05/21/08 10:00 119.94/29/08 6:0096.65/21/08 11:00 117.74/29/08 7:0098.95/21/08 12:00 119.94/29/08 8:0096.55/21/08 13:00 118.84/29/08 9:0096.35/21/08 14:00 118.54/29/08 10:0093.25/21/08 15:00 120.74/29/08 11:0090.95/21/08 16:00 123.54/29/08 12:0088.5/21/08 1 00121 44/29/08 13 0089 25/21/08 17:00 121.44/29/08 13:00.5/21/08 18:00 112.55/21/08 19:00 115.05/21/08 20:00 112.65/21/08 21:00 109.25/21/08 22:00 104.55/21/08 23:00 99.15/22/08 0:00 102.75/22/08 1:00 105.65/22/08 2:00 109.15/22/08 3:00 113.55/22/08 4:00 118.45/22/08 5:00 117.65/22/08 6:00 116.75/22/08 7:00 114.2

### Furnace 11: Classic Predictive Interval Calculations for 30 data Points Mean Stdev Count alpha 2-tail t upper level 111.04896 8.747557 176.0 0.01 2.604 115.5 0.05 1.974 114.5

Furnace 11: Bootstrap Results: 2000 replicates based on NOx lbs/hour Data Tool Mean SE(ave30) alpha 2-tail z upper level
Excel 2007 111.0 1.563 0.01 2.576 115.1 0.05 1.960 114.1

R 111.0 1.612 0.01 2.576 115.2 0.05 1.960 114.2

R 111.0 1.616 0.01 2.576 115.2 0.05 1.960 114.2

R 111.0 1.604 0.01 2.576 115.2 0.05 1.960 114.2

R 111.0 1.581 0.01 2.576 115.1 0.05 1.960 114.1

R 111.0 1.605 0.01 2.576 115.2 0.05 1.960 114.2

R 111 0 1 616 0 01 2 576 115 2

. . . . . 0.05 1.960 114.2

R 111.0 1.590 0.01 2.576 115.1 0.05 1.960 114.2

R 111.0 1.566 0.01 2.576 115.1 0.05 1.960 114.1

R 111.0 1.570 0.01 2.576 115.1 0.05 1.960 114.1

### > dataframe<-read.csv("C:\\Documents and Settings\\hjiang\\Desktop\\Data_R.csv",header=T) > names(dataframe) # A column of 176 values for Furnace 11 [1] "F11NOxlbphr" > attach(dataframe) > # set up the bootstrap > B <- 2000 # number of bootstrap replicates > n <- 30 # sample size, i.e., 30 data points as proposed by the MPCA > ave30 <- numeric(B) # storage for bootstrap replicates > # bootstrap estimate of standard error of ave30 > for (b in 1:B) { + # randomly select the indices + i <- sample(1:176, size=n, replace=T) # i is a vector of indices + ave30[b] <- mean(F11NOxlbphr[i]) # calc mean for each replicate + } > # output > print(se.ave30 <- sd(ave30)) # standard error (ave30) [1] 1.612113 > hist(ave30, prob=T)

Notes : When I run the above commands plus added: > set.seed(11) before entering the "> B <- 2000" command, I got: [1] 1.616225Histogram of Bootstrap Distribution (Excel, se = 1.563)

Histogram of Bootstrap Distribution (R, se = 1.612)

### Furnace 12: Classic Predictive Interval Calculations for 30 data Points Mean Stdev Count alpha 2-tail t upper level 98.9 10.318 158 0.01 2.608 104.3 0.05 1.975 103.0

Furnace 12: Bootstrap Results: 2000 replicates based on NOx lbs/hour Data Tool Mean SE(ave30) alpha 2-tail z upper level
Excel 2007 98.9 1.883 0.01 2.576 103.8 0.05 1.960 102.6

R 98.9 1.896 0.01 2.576 103.8 0.05 1.960 102.7

R 98.9 1.894 0.01 2.576 103.8 0.05 1.960 102.7

R 98.9 1.883 0.01 2.576 103.8 0.05 1.960 102.6Histogram of Bootstrap Distribution (Excel, se = 1.883)

Histogram of Bootstrap Distribution (R, se = 1.896)DEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### December 12, 2011 Office Memorandum

TO: 

### AQD File No. 869A (Delta ID No. 13700113)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### BART Limits for United Taconite (UTac)

This memo was prepared to provide the documentation of the MPCA’s NO X 

### BART limit determination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information 1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address United Taconite LLC – Fairlane Plant P.O. Box 180 Eveleth, Minnesota 55734-0180 Highway 16 Forbes, Minnesota 55738 St. Louis County Contact: Ms. Candice Maxwell; Phone: (218) 744-7849

1.2 Description of the Facility

The United Taconite, LLC (UTac) facility processes crude taconi te ore into a pellet product with ore supplied from a raillinked facility, UTac’s Thunderbird Mine. Fine crushing and grinding of crude ore and magnetic separation processes produce a taconite concentrate, which is used to make pelle ts. Taconite pellets are thermally hardened in a grate-kiln indurating furnace. The finished product (fired pellets) is transferred by conveyors to storage bins for holding and loading into railcars.

This facility has two indurating Allis-Chalmers furnaces. Line 1 is the smaller of the two, with a rated throughput of 280 tons of pellets per hour and a heat input of 190 MMBtu per hour of natural gas. The newer line, Li ne 2, is rated at 672 tons per hour with a heat input from natural gas, coal, petroleum coke, and other fuels of 400 MMBtu per hour.

2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

### The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology available and associated emission reductio ns achievable. The analysis must take into consideration the techno logy available, the costs of compliance, th e energy and non-air quality environmental impacts, any pollution control equipment in use at the source , the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The units for which the MPCA must determine BART and establish a NO X 

### BART limit consistent with that determination

are:

Emission Unit Name EU Number Stack Numbers Line 1 Pellet Induration EU040 SV046 Line 2 Pellet Induration EU042 SV048, SV049

2.3 The BART Determination

When the MPCA submitted the original Regional Haze SIP (December 2009), the Line 1 indurating furnace was able to burn both natural gas and fuel oil, but natural gas was the pr imary fuel. Since natural gas is low in sulfur, the primary source of sulfur at the Line 1 furnace was the iron ore us ed to form the green balls. Some additional sulfur may be present in additives also used in the green balls . Based on this operating scenario, the MPCA’s SO 2 

### BART determination for Line 1 was current operation of the wet scrubbers , with a corresponding emission limit of 0.121 lbs SO 2 

### /long ton of pellets produced.

The Line 2 indurating furnace is permitted to burn pulverized coal , a coal/pet coke blend, distilla te oil, and natural gas. It is primarily operated using a blend of coal and pet coke. Ther efore, the primary source of sulfur at this furnace is the fuel, though the iron ore also contributes some sulfur to the waste gas. The MPCA’s SO 2 

### BART determination for Line 2 was for fuel blending to reduce SO 2 

### emissions, with a corresponding emission limit of 1.7 lbs/MMBtu.

The MPCA’s BART determinations for the pellet induration furnaces are documented in Appendix 9.3 of the December 2009 Regional Haze SIP submittal.

The MPCA’s NO X 

### BART determination for Line 1 is good combusti on practices and implementation of a past heat recuperation project. The MPCA’s NO X 

### BART determination for Line 2 is good combustion practices. However, due to the lack of sufficient emissions data representing the range of operating conditions that influence emissions, the MPCA did not set an emission limit at the time of making the BART determination.

Instead, the MPCA and UTac entered into an Administrative Order, under which UTac provided additional NO X 

### emission information to the MPCA. Subsequently, UTac was required a Stipulation Agreement to install Continuous Emission Monitoring Systems (CEMS) on both lines. UTac certified the CEMS in late 2010, and began reporting information to the MPCA in 2011.

### 2.4 MPCA Determination of the “Baseline” BART Limit

Setting the BART limits for United Taconite is a two-step proc ess, because of a planned change in facility operations. The MPCA was unable to find guidance on how to evaluate approp riate BART limits for a modifying facility, particularly in this case where the BART determinations were made but data was not available to set matching emission limits.

The first step was to determine a “baseline BART” – BART for the unmodified facility. The MPCA reviewed the NO X 

### emission information provided by UTac. Although some data was received for November and December 2010, the MPCA focused on emission data from January through June 2011.

The 30-day rolling average of NO X 

### emissions from the two lines at UTac does not fit any standard statistical probably curve. Therefore, the calculation to set the emission limi t was done based on a normal curve. For Line 1, a 95% confidence interval was constructed, and the upper prediction level was used to the set the BART limit. For Line 2, a 99% confidence interval was constructed, and again the upper pred iction level was used to develop the BART limit. The upper prediction level was used, rather than the upper confidence le vel, due to the fact that compliance requires “gap filling” of missing data. This was not done in the CEMS data submittals thus far. The fact that gap filling was not completed and that a limited amount of data is availabl e, means that the available data likely do es not demonstrate the entire range of data. Because of these limitations of the data, the upper predic tion level is more appropriat e to use, and creates a limit that is slightly above the maximum emi ssions level shown in the available data. (A 99% confidence interval was used for Line 2 in order to ensure that the upper prediction le vel is above the maximum demonstrated emissions level.)

UTac NO X 

### Emissions Descriptive Statistics (30 day rolling average, lbs/hour) Line 1 NO X 

### Line 2 NO X 

### (Stack A) Line 2 NO X 

### (Stack B) # Data Points 111 142 181 Minimum 552.27 98.41 82.84 Mean 743.04 215.20 196.41 Standard Deviation 138.27 70.11 58.18

Maximum 952.33 364.14 345.01

After reviewing the CEMS data provided by UTac, the MPCA has determined that appropriate baseline BART NO X 

### limits are: 1018.3 lbs/hour for Line 1, and 753.8 lbs/hour for Line 2. Along with the emission limits set in the original SIP submittal, the baseline BART emission limits for the facility are as follows:

UTac Baseline BART Emissions Limits (30 day rolling average) Line 1 Line 2 SO 2 

### BART Limit 0.121 lbs/LT pellet 1.7 lbs/MMBtu NO X 

### BART Limit 1018.3 lbs/hour 753.8 lbs/hour

### 2.5 Facility Changes and the BART Limit

In August 2010, after the MPCA determined the BART work practices and controls fo r UTac, the facility received a permit amendment that allows for the use of solid fuels on Line 1 and a facility-wide production increase.

Because of this change, certain requirements were placed in the amended permit. Within 120 days of receiving a memo documenting the baseline BART limits set in part 2.4 fr om the MPCA, UTac must subm it to the MPCA a permit application to incorporate into its air emission permit either 1) NO X 

### and SO 2 

### BART emission limits as described in this memo or 2) a BART alternative as desc ribed in the December 2009 Regional Haze SIP submittal. Alternatively, UTac may submit within 120 days an updated BART analysis based on the modified Lines 1 and 2 for the facility with an appropriate permit amendment application to incorporate the BART limits proposed in that update analysis. The MPCA sent documentation of the initial BART limits on September 22, 2011.

On December 8, 2011, UTac provided MPCA with a proposal requesting that the permit limits from the permit issued in August 2010 be used as the BART limits for the facility.

UTac Proposed BART Emission Limits

Line 1 (EU040) Line 2 (EU042) SO 2 

### Limit 106.3 tons as a 30-day rolling sum 197 tons as a 30-day rolling sum NO X 

### Limit 816 tons as a 180-day rolling sum 1820 tons as a 180-day rolling sum

UTac and MPCA then calculated the emission reductions that would result from this proposal, compared to the MPCA’s original BART proposal. The following tabl e shows the MPCA’s calculation of annua l emissions from the facility prior to BART, using baseline actual emissions (Past Emissions), the MPCA’s baseline BART proposal, and UTac’s BART proposal. These were calculated using the maximum pellet production and heat input for each furnace.

Annual Emissions from UTac (tons per year) Full Furnace Capacity 1


### Line 1 Line 2 Total NO X 

### SO 2 

### NO X 

### SO 2 

### NO X 

### SO 2 

### Past Emissions 2 

### 4371 38 1968 7008 6338 7046 MPCA Baseline BART 4460 148 3302 2978 7762 3127 UTac BART Proposal 1655 1293 3692 2394 5347 3687

This demonstrates that the MPCA’s baseline BART prop osal is essentially unconstraining, except for the SO 2 

### emissions limit for Line 2. Compared to past actu al emissions, the MPCA’s baseline BART pr oposal results in about a 2500 tons per year decrease in overall emissions of NO X 

### and SO 2 

### . The proposal by UTac results in a 4350 tons per year decrease in overall emissions as compared to the past emission scenar io, and 1855 tons per year as compared to MPCA’s BART determination.

However, because visibility is looked at in terms of best and worst days, a shorter-term limit is needed for emissions averaging. The generally accepted averaging time for BART limits is a 30-day rolling average.

1 Estimates of emissions for the past emissio ns and MPCA proposals were done usin g the maximum furnace throughput and assuming 8760 hours of operation annually.

2 Because the facility does not have NO X emission limits, the past emissions for NO X were estimated using baseline actuals from the August 2010 permitting action. Line 1 SO 2 unlimited emissions were estimated the same way, while Line 2 SO 2 unlimited emissions were estimated using the statewide 4.0 lbs/MMBtu emission limit, which is higher th an the baseline actuals of 3652 tpy.

### The following table looks at the past emissions and the MPCA and UTac BART proposals on a tons per day basis, at full furnace capacity.

Daily Emissions from UTac (tons per day) Full Furnace Capacity 3


### Line 1 Line 2 NO X 

### SO 2 

### NO X 

### SO 2 

### Past Emissions 4 

### 11.97 0.10 5.39 19.20 MPCA Baseline BART 12.22 0.41 9.05 8.16 UTac BART Proposal 4.53 3.54 10.11 6.57

Although this scenario raises the SO 2 

### limit on Line 1 to account for the addition of solid fuels, it results in lower NO X 

### limits on both lines and lower SO 2 

### limits on Line 2 than the MPCA’s baseline BA RT proposal. This, combined with the total annual emissions decrease, leads the MPCA to determin e the following limits are BART for United Taconite.

Unit BART NO X 

### Limit (tons per day, 30-day rolling average) BART SO 2 

### limit (tons, 30-day rolling sum) Line 1 (EU040) 4.5 106.3 Line 2 (EU042) 10.1 197

The limit for Line 2 applies to emissions from both stacks. Compliance will be determined through the use of CEMS.

3 Estimates of emissions from the unlimited and MPCA proposals we re done using the maximum furn ace throughput and assuming 8760 hours of operation annually. The unlim ited emissions also include the baseline

4 Because the facility does not have NO X emission limits, the unlimited emissions for NO X were estimated using baseline actuals from the August 2010 permitting action. Line 1 SO 2 unlimited emissions were estimated the same way, while Line 2 SO 2 unlimited emissions were estimated using the statewide 4.0 lbs/MMBtu emission limit, which is higher than th e baseline actuals of 3652 tp y.Line 1Furnace Capacity 280 tons pellets/hour190 MMBtu/hr2,452,800 tons pellets/yearProposed Operations (From 8/10 Permit)250 tons pellets/hour0.61 MMBtu/LT pellets 1,950,000 tons pellets/year1,189,500 MMBtu/yearPast Emissions Estimate - L1 on Natural Gas - Full Furnace Capacitylbs/hour lbs/day tons per day tons per yearNOX3.5639 lbs/long tons pellet 997.892 23949.41 11.97 4371 Estimated using baseline Actuals from 8/10 permitSO20.0308 lbs/long tons pellet 8.624206.980.1038 Estimated using baseline Actuals from 8/10 permitPast Emissions Estimate - L1 on Natural Gas - Proposed OperationsNOX3.5639 lbs/long tons pellet 890.975 21383.40 10.69 3475SO20.0308 lbs/long tons pellet 7.7184.800.0930Potential Emissions Estimate - L1 on Solid Fuels - Full Furnace CapacityNOX0.6685 lbs/long tons pellet 187.18 4492.32 2.25820 Baseline Actual emission factor from Line 2SO24.0 lbs/MMBtu76018240.00 9.12 3329 Using statewide 4.0 emission factorPotential Emissions Estimate - L1 on Solid Fuels - Proposed OperationsNOX0.6685 lbs/long tons pellet 167.125 4011.00 2.01652 Baseline Actuals emission factor for Line 2SO24.0 lbs/MMBtu61014640.00 7.32 2379 Using statewide 4.0 emission factorMPCA Limit - L1 on Natural Gas - Full Furnace CapacityNOX1018.3 lbs/hour1018.3 24439.2 12.22 4460SO20.121 lbs/long tons pellet 33.88813.120.41148MPCA Limit - Proposed OperationsNOX1018.3 lbs/hour39717800 hours of operation annuallySO20.121 lbs/long tons pellet118Utac Proposed Limit - Full Furnace CapacityNOX816 tons/180 days4.53 1655SO2106.3 tons/30 days3.54 12931.7 lbs/MMBtu32377523.88 1415 Sample calculation, based on baseline SO2 BART for Line 2Line 2Furnace Capacity672 tons pellets/hour400 MMBtu/hrProposed Operations 4,050,000 tons pellets/year0.52 MMBtu/LT2,106,000 MMBtu/yearPast Emissions Estimate - Full Furnace Capacitylbs/hour lbs/day tons per day tons per yearNOX0.6685 lbs/long tons pellets 449.232 10781.568 5.39 1968 Estimated using baseline Actuals from Last PermitSO24.0 lbs/MMBtu160038400 19.20 7008 Using 4.0 emission factor; baseline actuals were 3652Past Emissions Estimate - Proposed OperationsNOX0.6685 lbs/long tons pellets1354 Estimated using baseline Actuals from Last PermitSO24.0 lbs/MMBtu4212 Using 4.0 emission factor; baseline actuals were 3652MPCA Limit - Full Furnace CapacityNOX753.8 lbs/hour753.818091.2 9.05 3302SO21.7 lbs/MMBtu680.0163208.16 2978MPCA Limit - Proposed OperationsNOX753.8 lbs/hour22716027 hours of operation annuallySO21.7 lbs/MMBtu1790Utac Proposed Limittons per day tons per yearNOX1820 tons/180 days10.11 3692SO2197 tons/30 day6.57 2394Reported Actual Emissions from UTac200720082009NOX426335401968SO2365437262936Total Emissions - Full Furnace Capacity NOXSO2Past and Unmodified63387046MPCA BART77623127MPCA - Past1423-3919-2496Utac BART53473687Utac BART - Past-991-3359-4350Utac BART - MPCA-2415560-1855Total Emissions - Proposed Operations NOXSO2Past and Unmodified48294242Using baseline actuals and proposed future annual throughput.MPCA BART62431908Using proposed annual throughput.MPCA - Past1414-2334-920Utac BART53473687Utac BART - Past518-555-37Utac BART - MPCA-8961779883DEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### October 7, 2011 Office Memorandum

TO: 

### AQD File No. 62B (Delta ID No. 13700063)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### Nitrogen Oxides BART Limits for U.S. Steel – Keewatin Taconite (Keetac)

This memo was prepared to provide the documentation of the MPCA’s NO X 

### and SO 2 

### BART limit determ ination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information

1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address U.S. Steel – Keewatin Taconite P.O. Box 217 Keewatin, MN 55753-0217 1 Mine Road Keewatin, Minnesota 55753 St. Louis County Contact: Mr. Ryan Siats; Phone (218) 778-8684

1.2 Description of the Facility

U.S. Steel owns and operates a taconite mine and proce ssing facility in Keewatin, Minnesota, known as Keetac. At Keetac, U.S. Steel operates one grate-kiln furnace (the “P hase II furnace;” EU030) constr ucted in 1976. The furnace is capable of processing 415 tons of pellets per hour with a heat input of 178.5 MMBtu/hr.

The permit for the Keetac facility allows the combustion of na tural gas, distillate fuel oils , coal, and petroleum coke in the pelletizing furnace. Coal and natural gas are the primary fuel s; coal is a significant source of sulfur. Another source of sulfur emissions from this furnace is the iron ore used to form the green balls, although this represents a smaller contribution than the sulfur in the solid fuels burned. Sulf ur dioxide emissions are currently controlled by wet scrubbers.

2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology ava ilable and associated achievable emission limits. The analysis must take into

### consideration the technology available, the costs of compliance, the energy and non-air quality environmental impacts, any pollution control equipment in use at the source, th e remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The units for which the MPCA must determine BART and estab lish emission limits consistent with that determination

are:

Emission Unit Name EU Number 1 

### Control Equipment and Stack Numbers Phase II Grate-Kiln Pelletizing Furnace EU030 CE110, CE111/SV051

2.3 The BART Determination

The MPCA’s BART determinations for this unit is documented in A ppendix 9.3 of the December 2009 Regional Haze SIP submittal.

The NO X 

### BART determination for the Phase II furnace is existing combustion controls and fuel blending, along with good combustion practices.

However, due to the lack of sufficient emissions data repr esenting the range of operating conditions that influence emissions, the MPCA did not set an emission limit at the time of making the BART determination for the indurating furnaces. Instead, the MPCA and Keetac entered into an Admi nistrative Order, under which Keetac agreed to install and maintain Continuous Emissions Moni toring Systems (CEMS) and provide NO X 

### emission information to the MPCA.

The SO 2 

### BART determination is operation of the existing wet scrubber. However, as with NO X 

### , additional emission information was needed prior to setting an SO 2 

### limit from this primarily coal-fir ed furnace. Keetac agreed in an Administrative Order to install and maintain SO 2 

### CEMS and provide emission information to the MPCA.

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NO X 

### and SO 2 

### emission information provided by Keetac.

NO X 

### emission data was received going back to November 2008, but the Keetac fac ility was shut down for a year from early December 2008 through late December 2009. (Only a few days of operating data were received for December 2009.) Therefore, the MPCA’s review focused on the most recent data after Keetac’s return to operations in December 2009. Data from late January 2010 through the end of Marc h 2011 was analyzed to develop the BART limits.

The following graphs show the variation in emissions over the analyzed time frame, along with the frequency of measurements of each emission level.

1 The MPCA organizes conditions and illustrates associations in its permits using the Emission Un it (EU), Control Equipment (CE ), and Stack/Vent (SV) numbers.

### Frequency of NO X 

### Emissions (tpd) NO X 

### Emissions Over Time (tpd)

Frequency of SO 2 

### Emissions (tpd) SO 2 

### Emissions Over Time (tpd)

### The following table shows descriptive statistics of the NO X 

### and SO 2 

### emissions from the furnace, in tons per day.

Keetac Emissions Descriptive Statistics (30 day rolling average, tons per day) Furnace NO X 

### Furnace SO 2 

### # Data Points 429 429 Minimum 6.390 0.4953 Mean 9.535 1.569 Median 9.587 1.789 Maximum 12.476 2.639

The most recent data was plotted to the most appropriate statistical probability distribution, and a 98% confidence interval was constructed. The limit was based on the upper confidence level.

A reviewing the CEMS data provided by Keetac, the MPCA ha s determined that the appropriate BART limits are those shown in the following table.

Keetac BART Limits (30 day rolling average, tons per day) Furnace NO X 

### Furnace SO 2 

### BART Limit 12.35 2.71

These limits are 30-day rolling averages. Compliance is to be determined through the continued use of CEMS.

### Proposed Keetac BART Limits (ton/day) calculated as a 30-day rolling average Phase 2 pelletizer NOx SO2 Proposed limit 12.35 2.71 ton/day Pattern; %-tile Weibull; 98 Weibull; 98 based on the data of recent rows (1/26/2010-3/31/2011)

c.f. Max 12.48 2.64 based on the data of recent rows 1040 220 uniform emission rate, lb/h r

Limit/Ma x 99% 103%

1029 225.8 uniform limit, lb/h r 1032 240 gap filling value permittee used in submittal

2.00 4.00 6.00 8.00 10.00 12.00 14.00 

# NOx

0.00 2.00

400 450 500 550 600 650 700 750 800 850 900

0.00 0.50 1.00 1.50 2.00 2.50 3.00

400 450 500 550 600 650 700 750 800 850 900 

# SO2All rows of data:

Recent rows (1/26/2010-3/31/2011 )Recent rows (1/26/2010-3/31/2011 )

Commands entered at R Console (7/29/2011) R 2.1.3.0 R for Windows GUI front-end > dataframe<-read.csv("C:\\Documents and Se ttings\\hjiang\\Desktop\\Data_R.csv",header=T) > names(dataframe) [1] "SimpleDay" "NOx" > attach(dataframe) > summary(dataframe)

SimpleDay NOx Min. : 0 Min. : 0.000 1st Qu.: 218.5 1st Qu.: 0.000 Median :437.0 Median : 7.257 Mean : 437.0 Mean : 5.192 3rd Qu.: 655.5 3rd Qu.: 9.699 M 874 M 12 476 Max. : 874 Max. :12.476 > hist(NOx,prob=T)

SimpleDay NOx SO2 Min. : 445 Min. : 6.390 Min. : 0.4953 1st Qu.: 552.2 1st Qu.: 8.595 1st Qu.: 1.0800 Median :659.5 Median : 9.587 Median :1.7890 Mean : 659.5 Mean : 9.535 Mean : 1.5694 3rd Qu.: 766.8 3rd Qu.: 10.341 3rd Qu.: 2.0234 Max. : 874 Max. : 12.476 Max. : 2.6393 > hist(NOx,prob=T) > hist(SO2,prob=T) > plot(SimpleDay,NOx)Keetac Phase II NOx 30-day rolling average , ton/day, as submitted Date SimpleDay NOx SO2 11/7/08 0 0.20 0.031 11/8/08 1 0.61 0.077 11/9/08 2 1.02 0.113 11/10/08 3 1.41 0.157 11/11/08 4 1.76 0.202 11/12/08 5 2.06 0.265 11/13/08 6 2.40 0.330 11/14/08 7 2.72 0.394 11/15/08 8 3.07 0.446 11/16/08 9 3.44 0.499 11/17/08 10 3.88 0.553 11/18/08 11 4.21 0.597 11/19/08 12 4.55 0.625 11/20/08 13 4.87 0.665 11/21/08 14 5.25 0.708 11/22/08 15 5.54 0.751 11/23/08 16 5.83 0.793 11/24/08 17 6.05 0.833 11/25/08 18 6.33 0.872 11/26/08 19 6.66 0.892 11/27/08 20 7.08 0.940 11/28/08 21 7.50 1.007 11/29/08 22 7.91 1.059 11/30/08 23 8.28 1.078

12/1/08 24 8.62 1.114 12/2/08 25 8.90 1.149 12/3/08 26 9.40 1.171 12/4/08 27 9.62 1.177 12/5/08 28 0.00 0.000 No data until 12/27/09 Blank was submitted. 12/28/09 416 9.29 0.000 Not calc'd in the submittal 12/29/09 417 12.38 0.000 12/30/09 418 12.38 0.000 12/31/09 419 12.38 0.000 1/1/10 420 11.56 2.71 1/2/10 421 10.32 2.70 1/3/10 422 8.85 2.66 1/4/10 423 9.57 2.58 1/5/10 424 9.20 2.51 1/6/10 425 9.70 2.49 1/7/10 426 10.05 2.37 1/8/10 427 9.84 2.34 1/9/10 428 10.25 2.30 1/10/10 429 10.70 2.23 1/11/10 430 11.16 2.18 1/12/10 431 11.29 2.10 1/13/10 432 11.32 2.03 1/14/10 433 11.12 1.95 1/15/10 434 11.12 1.93 1/16/10 435 10.95 1.94 1/17/10 436 10.74 1.96 1/18/10 437 10.53 1.96 1/19/10 438 10.38 1.961/20/10 439 10.18 1.97 1/21/10 440 10.02 1.96 1/22/10 441 9.85 1.94 1/23/10 442 9.71 1.93 1/24/10 443 9.60 1.93 1/25/10 444 9.51 1.93 1/26/10 445 9.41 1.94 1/27/10 446 9.34 1.92 1/28/10 447 9.20 1.87 1/29/10 448 8.97 1.83 1/30/10 449 8.69 1.77 1/31/10 450 8.54 1.73

2/1/10 451 8.61 1.71 2/2/10 452 8.83 1.71 2/3/10 453 8.59 1.72 2/4/10 454 8.59 1.74 2/5/10 455 8.42 1.73 2/6/10 456 8.19 1.76 2/7/10 457 8.17 1.78 2/8/10 458 7.88 1.81 2/9/10 459 7.61 1.84 2/10/10 460 7.34 1.85 2/11/10 461 7.26 1.90 2/12/10 462 6.92 1.89 2/13/10 463 6.73 1.87 2/14/10 464 6.70 1.87 2/15/10 465 6.73 1.88 2/16/10 466 6.82 1.88 2/17/10 467 6.98 1.90 2/18/10 468 7.06 1.91 2/19/10 469 7.21 1.92 2/20/10 470 7.34 1.93 2/21/10 471 7.48 1.94 2/22/10 472 7.39 1.90 2/23/10 473 7.57 1.94 2/24/10 474 7.75 1.97 2/25/10 475 7.95 1.99 2/26/10 476 8.06 2.03 2/27/10 477 8.05 2.05 2/28/10 478 8.12 2.05

3/1/10 479 8.27 2.07 3/2/10 480 8.34 2.08 3/3/10 481 8.46 2.06 3/4/10 482 8.58 2.02 3/5/10 483 8.68 2.01 3/6/10 484 8.84 1.99 3/7/10 485 8.87 1.97 3/8/10 486 8.98 1.96 3/9/10 487 9.08 1.93 3/10/10 488 9.16 1.90 3/11/10 489 9.16 1.88 3/12/10 490 9.11 1.84 3/13/10 491 9.00 1.83 3/14/10 492 9.24 1.88 3/15/10 493 9.46 1.943/16/10 494 9.18 1.90 3/17/10 495 9.01 1.85 3/18/10 496 8.96 1.85 3/19/10 497 8.90 1.85 3/20/10 498 8.86 1.86 3/21/10 499 8.81 1.88 3/22/10 500 8.78 1.89 3/23/10 501 8.77 1.92 3/24/10 502 9.10 1.94 3/25/10 503 8.97 1.92 3/26/10 504 8.84 1.89 3/27/10 505 8.61 1.84 3/28/10 506 8.59 1.84 3/29/10 507 8.63 1.87 3/30/10 508 8.68 1.91 3/31/10 509 8.79 1.93

4/1/10 510 8.76 1.97 4/2/10 511 8.67 2.02 4/3/10 512 8.58 2.07 4/4/10 513 8.48 2.08 4/5/10 514 8.39 2.10 4/6/10 515 8.34 2.13 4/7/10 516 8.30 2.14 4/8/10 517 8.22 2.16 4/9/10 518 8.19 2.16 4/10/10 519 8.32 2.16 4/11/10 520 8.36 2.20 4/12/10 521 8.52 2.20 4/13/10 522 8.56 2.20 4/14/10 523 8.62 2.21 4/15/10 524 8.96 2.26 4/16/10 525 9.22 2.30 4/17/10 526 9.36 2.30 4/18/10 527 9.59 2.26 4/19/10 528 9.90 2.21 4/20/10 529 9.79 2.15 4/21/10 530 9.49 2.07 4/22/10 531 9.17 1.98 4/23/10 532 8.73 1.93 4/24/10 533 8.45 1.86 4/25/10 534 8.16 1.80 4/26/10 535 7.99 1.75 4/27/10 536 7.66 1.66 4/28/10 537 7.35 1.56 4/29/10 538 7.05 1.46 4/30/10 539 6.66 1.38

5/1/10 540 6.39 1.29 5/2/10 541 6.39 1.24 5/3/10 542 6.53 1.21 5/4/10 543 6.67 1.20 5/5/10 544 6.79 1.18 5/6/10 545 6.91 1.16 5/7/10 546 6.99 1.16 5/8/10 547 7.15 1.14 5/9/10 548 7.34 1.145/10/10 549 7.34 1.15 5/11/10 550 7.46 1.16 5/12/10 551 7.46 1.15 5/13/10 552 7.52 1.15 5/14/10 553 7.59 1.14 5/15/10 554 7.53 1.17 5/16/10 555 7.46 1.21 5/17/10 556 7.39 1.24 5/18/10 557 7.17 1.29 5/19/10 558 6.90 1.33 5/20/10 559 7.01 1.40 5/21/10 560 7.27 1.51 5/22/10 561 7.51 1.67 5/23/10 562 7.74 1.84 5/24/10 563 7.99 1.97 5/25/10 564 8.34 2.04 5/26/10 565 8.67 2.11 5/27/10 566 9.00 2.19 5/28/10 567 9.39 2.26 5/29/10 568 9.70 2.34 5/30/10 569 10.04 2.43 5/31/10 570 10.40 2.52

6/1/10 571 10.37 2.53 6/2/10 572 10.31 2.54 6/3/10 573 10.21 2.55 6/4/10 574 10.01 2.55 6/5/10 575 9.88 2.53 6/6/10 576 9.73 2.53 6/7/10 577 9.55 2.56 6/8/10 578 9.40 2.59 6/9/10 579 9.30 2.58 6/10/10 580 9.18 2.54 6/11/10 581 9.03 2.57 6/12/10 582 8.98 2.61 6/13/10 583 8.98 2.64 6/14/10 584 8.94 2.62 6/15/10 585 8.84 2.60 6/16/10 586 8.75 2.58 6/17/10 587 8.70 2.56 6/18/10 588 8.76 2.53 6/19/10 589 8.78 2.51 6/20/10 590 8.82 2.47 6/21/10 591 8.87 2.41 6/22/10 592 9.04 2.31 6/23/10 593 9.11 2.25 6/24/10 594 9.13 2.26 6/25/10 595 9.09 2.26 6/26/10 596 9.12 2.25 6/27/10 597 9.10 2.23 6/28/10 598 9.16 2.21 6/29/10 599 9.16 2.19 6/30/10 600 9.16 2.16

7/1/10 601 8.70 2.11 7/2/10 602 8.50 2.07 7/3/10 603 8.46 2.067/4/10 604 8.56 2.07 7/5/10 605 8.60 2.09 7/6/10 606 8.76 2.07 7/7/10 607 8.86 2.07 7/8/10 608 8.82 2.13 7/9/10 609 8.93 2.14 7/10/10 610 9.07 2.17 7/11/10 611 9.27 2.12 7/12/10 612 9.64 2.07 7/13/10 613 9.95 2.05 7/14/10 614 9.94 2.04 7/15/10 615 9.97 2.02 7/16/10 616 9.99 2.02 7/17/10 617 9.99 2.01 7/18/10 618 9.86 2.02 7/19/10 619 9.80 2.01 7/20/10 620 9.82 2.01 7/21/10 621 9.88 2.01 7/22/10 622 9.82 2.02 7/23/10 623 9.82 2.02 7/24/10 624 9.80 2.01 7/25/10 625 9.87 2.01 7/26/10 626 9.93 1.99 7/27/10 627 9.91 2.00 7/28/10 628 9.87 2.02 7/29/10 629 9.85 2.04 7/30/10 630 9.79 2.08 7/31/10 631 9.83 2.11

8/1/10 632 9.82 2.13 8/2/10 633 9.87 2.15 8/3/10 634 9.88 2.17 8/4/10 635 9.92 2.19 8/5/10 636 9.88 2.22 8/6/10 637 9.92 2.21 8/7/10 638 9.96 2.20 8/8/10 639 9.90 2.22 8/9/10 640 9.82 2.23 8/10/10 641 9.69 2.26 8/11/10 642 9.61 2.24 8/12/10 643 9.66 2.23 8/13/10 644 9.70 2.22 8/14/10 645 9.67 2.21 8/15/10 646 9.80 2.17 8/16/10 647 9.91 2.13 8/17/10 648 10.01 2.10 8/18/10 649 10.11 2.09 8/19/10 650 10.13 2.07 8/20/10 651 10.06 2.04 8/21/10 652 10.01 2.01 8/22/10 653 10.01 1.97 8/23/10 654 10.02 1.94 8/24/10 655 10.05 1.93 8/25/10 656 10.02 1.93 8/26/10 657 10.06 1.92 8/27/10 658 10.06 1.918/28/10 659 10.10 1.91 8/29/10 660 10.14 1.87 8/30/10 661 10.06 1.86 8/31/10 662 10.03 1.85

9/1/10 663 10.03 1.83 9/2/10 664 10.09 1.81 9/3/10 665 10.10 1.80 9/4/10 666 10.08 1.79 9/5/10 667 10.06 1.80 9/6/10 668 10.03 1.82 9/7/10 669 10.06 1.84 9/8/10 670 10.00 1.86 9/9/10 671 10.05 1.86 9/10/10 672 10.04 1.89 9/11/10 673 10.05 1.89 9/12/10 674 10.05 1.90 9/13/10 675 10.17 1.91 9/14/10 676 10.10 1.97 9/15/10 677 10.04 2.02 9/16/10 678 10.03 2.05 9/17/10 679 10.05 2.07 9/18/10 680 10.23 2.07 9/19/10 681 10.43 2.06 9/20/10 682 10.44 2.06 9/21/10 683 10.43 2.06 9/22/10 684 10.54 2.05 9/23/10 685 10.58 2.02 9/24/10 686 10.64 2.00 9/25/10 687 10.74 1.98 9/26/10 688 10.88 1.96 9/27/10 689 10.97 1.93 9/28/10 690 11.10 1.91 9/29/10 691 11.27 1.88 9/30/10 692 11.48 1.86 10/1/10 693 11.65 1.85 10/2/10 694 11.81 1.83 10/3/10 695 11.96 1.81 10/4/10 696 12.14 1.79 10/5/10 697 12.25 1.76 10/6/10 698 12.41 1.72 10/7/10 699 12.08 1.64 10/8/10 700 11.77 1.55 10/9/10 701 11.39 1.48 10/10/10 702 11.06 1.40 10/11/10 703 10.76 1.36 10/12/10 704 10.83 1.36 10/13/10 705 10.88 1.33 10/14/10 706 10.95 1.28 10/15/10 707 11.02 1.23 10/16/10 708 11.04 1.18 10/17/10 709 11.07 1.13 10/18/10 710 10.96 1.11 10/19/10 711 10.82 1.11 10/20/10 712 10.88 1.09 10/21/10 713 10.94 1.0710/22/10 714 10.84 1.09 10/23/10 715 10.77 1.10 10/24/10 716 10.69 1.11 10/25/10 717 10.59 1.10 10/26/10 718 10.47 1.10 10/27/10 719 10.41 1.08 10/28/10 720 10.35 1.06 10/29/10 721 10.27 1.04 10/30/10 722 10.13 1.01 10/31/10 723 9.99 0.98

11/1/10 724 9.83 0.96 11/2/10 725 9.70 0.93 11/3/10 726 9.60 0.91 11/4/10 727 9.61 0.89 11/5/10 728 9.67 0.86 11/6/10 729 10.06 0.89 11/7/10 730 10.53 0.93 11/8/10 731 10.99 0.96 11/9/10 732 11.44 0.99 11/10/10 733 11.78 1.01 11/11/10 734 11.83 0.96 11/12/10 735 11.92 0.95 11/13/10 736 11.95 0.95 11/14/10 737 11.98 0.95 11/15/10 738 12.08 0.95 11/16/10 739 12.10 0.96 11/17/10 740 12.17 0.95 11/18/10 741 12.25 0.93 11/19/10 742 12.26 0.91 11/20/10 743 12.27 0.90 11/21/10 744 12.32 0.90 11/22/10 745 12.33 0.90 11/23/10 746 12.32 0.91 11/24/10 747 12.31 0.93 11/25/10 748 12.32 0.94 11/26/10 749 12.32 0.96 11/27/10 750 12.31 0.98 11/28/10 751 12.32 0.99 11/29/10 752 12.35 1.01 11/30/10 753 12.40 1.03

12/1/10 754 12.44 1.04 12/2/10 755 12.48 1.05 12/3/10 756 12.47 1.05 12/4/10 757 12.38 1.06 12/5/10 758 12.25 1.07 12/6/10 759 12.16 1.08 12/7/10 760 12.19 1.09 12/8/10 761 12.16 1.11 12/9/10 762 12.06 1.12 12/10/10 763 12.06 1.14 12/11/10 764 12.04 1.15 12/12/10 765 12.07 1.16 12/13/10 766 12.16 1.17 12/14/10 767 12.20 1.20 12/15/10 768 12.09 1.2012/16/10 769 12.05 1.20 12/17/10 770 11.98 1.18 12/18/10 771 11.93 1.17 12/19/10 772 11.91 1.17 12/20/10 773 11.87 1.15 12/21/10 774 11.80 1.13 12/22/10 775 11.72 1.12 12/23/10 776 11.69 1.10 12/24/10 777 11.63 1.09 12/25/10 778 11.61 1.08 12/26/10 779 11.57 1.06 12/27/10 780 11.48 1.05 12/28/10 781 11.38 1.04 12/29/10 782 11.29 1.01 12/30/10 783 11.22 0.99 12/31/10 784 11.21 1.02 1/1/11 785 11.21 1.09 1/2/11 786 11.23 1.17 1/3/11 787 11.26 1.24 1/4/11 788 11.30 1.31 1/5/11 789 11.37 1.37 1/6/11 790 11.22 1.39 1/7/11 791 11.07 1.36 1/8/11 792 11.10 1.40 1/9/11 793 10.98 1.39 1/10/11 794 10.78 1.36 1/11/11 795 10.52 1.34 1/12/11 796 10.27 1.31 1/13/11 797 10.06 1.26 1/14/11 798 9.94 1.27 1/15/11 799 9.86 1.26 1/16/11 800 9.61 1.25 1/17/11 801 9.37 1.26 1/18/11 802 9.32 1.29 1/19/11 803 9.23 1.32 1/20/11 804 9.13 1.33 1/21/11 805 8.99 1.33 1/22/11 806 8.67 1.30 1/23/11 807 8.37 1.26 1/24/11 808 8.03 1.22 1/25/11 809 7.90 1.20 1/26/11 810 7.80 1.18 1/27/11 811 7.77 1.17 1/28/11 812 7.72 1.18 1/29/11 813 7.67 1.19 1/30/11 814 7.56 1.15 1/31/11 815 7.50 1.06

2/1/11 816 7.46 0.98 2/2/11 817 7.40 0.91 2/3/11 818 7.24 0.83 2/4/11 819 7.07 0.74 2/5/11 820 7.00 0.67 2/6/11 821 7.02 0.66 2/7/11 822 6.99 0.59 2/8/11 823 7.03 0.582/9/11 824 7.18 0.59 2/10/11 825 7.29 0.59 2/11/11 826 7.41 0.59 2/12/11 827 7.51 0.60 2/13/11 828 7.57 0.59 2/14/11 829 7.63 0.59 2/15/11 830 7.66 0.61 2/16/11 831 7.81 0.62 2/17/11 832 7.78 0.61 2/18/11 833 7.86 0.60 2/19/11 834 7.99 0.61 2/20/11 835 8.17 0.63 2/21/11 836 8.53 0.67 2/22/11 837 8.84 0.71 2/23/11 838 9.18 0.74 2/24/11 839 9.35 0.76 2/25/11 840 9.46 0.78 2/26/11 841 9.52 0.79 2/27/11 842 9.66 0.80 2/28/11 843 9.74 0.80

3/1/11 844 9.81 0.81 3/2/11 845 9.85 0.81 3/3/11 846 9.77 0.80 3/4/11 847 9.75 0.79 3/5/11 848 9.71 0.77 3/6/11 849 9.66 0.77 3/7/11 850 9.70 0.78 3/8/11 851 9.72 0.79 3/9/11 852 9.63 0.79 3/10/11 853 9.58 0.78 3/11/11 854 9.52 0.78 3/12/11 855 9.50 0.78 3/13/11 856 9.47 0.78 3/14/11 857 9.45 0.78 3/15/11 858 9.47 0.79 3/16/11 859 9.42 0.79 3/17/11 860 9.55 0.80 3/18/11 861 9.62 0.78 3/19/11 862 9.69 0.77 3/20/11 863 9.61 0.76 3/21/11 864 9.53 0.74 3/22/11 865 9.45 0.72 3/23/11 866 9.35 0.68 3/24/11 867 9.27 0.65 3/25/11 868 9.15 0.62 3/26/11 869 9.06 0.61 3/27/11 870 9.00 0.59 3/28/11 871 8.93 0.57 3/29/11 872 8.84 0.53 3/30/11 873 8.79 0.51 3/31/11 874 8.73 0.50DEPARTMENT: 

### POLLUTION CONTROL AGENCY SF-00006-05 (4/86) STATE OF MINNESOTA

DATE: 

### October 26, 2011 Office Memorandum

TO: 

### AQD File No. 26A (Delta ID No. 13700005)

FROM: 

### Hongming Jiang Air Quality Permits Section Industrial Division Catherine Neuschler Air Assessment and Environmenta l Data Management Section Environmental Analysis and Outcomes Division

PHONE: 

### 651-757-2467 651-757-2607

SUBJECT: 

### Nitrogen Oxides BART Limits for U.S. St eel – Minnesota Ore Operations (Minntac)

This memo was prepared to provide the documentation of the MPCA’s NO X 

### and SO 2 

### BART limit determ ination based on the technical review performed by MPCA staff. EPA’s approval of the Regional Haze State Implementation Plan (SIP) for Minnesota is needed for the MPCA’s BART determination to become effective.

1. General Information

1.1 Applicant and Stationary Source Location:

Applicant/Mailing Address Stationary Source (SIC: 1011 )/Address U.S. Steel Corp. Minn esota Ore Operations P.O. Box 417 Mountain Iron, MN 55768 Minntac County Highway 102 Mountain Iron; St. Louis County Contact: Ms. Chrissy Bart ovich; Phone (218) 749-7364

1.2 Description of the Facility

U.S. Steel – Minnesota Ore Operations (Minntac) owns and operates a taconite mine and processing facility at County Highway 102, on the Mesabi Range north of the City of Mountain Iron, St. Louis County, Minnesota.

Minntac operates five indurating furnaces (Lines 3, 4, 5, 6, and 7). Line 3 (Step I) began operation in 1967; Lines 4 and 5 (Step II) began operation in 1972; and Lines 6 and 7 (Step III) began operation in 1978. This memorandum describes the MPCA’s determination of the NO X 

### BART limit for these five lines, along with the SO 2 

### BART limit for Lines 6 and 7.

2. Regulatory and/or Statutory Basis

2.1 Overview of Visibility, Regional Haze, and Best Available Retrofit Technology Program

The U.S. EPA’s 1999 Regional Haze Rule singles out certain ol der emission sources that have not been regulated under other provisions of the Clean Air Act for additional controls . The MPCA is required to determine Best Available Retrofit Technology (BART) for these ol der sources that contribute to visibility impa irment in Class I Areas to install Best Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA publishe d a revised final rule, including 40 CFR 51, Appendix Y “Guidelines for BART Determinations Under the Regional Haze Rule” which provides direction for determining which older sources may need to install BART and for determining BART.

The MPCA is required to determine BART fo r each source subject to BART based on an analysis of the best system of continuous emission control technology available and associated emission reductio ns achievable. The analysis must take into consideration the techno logy available, the costs of compliance, th e energy and non-air quality environmental

### impacts, any pollution control equipment in use at the source , the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be an ticipated to result from use of the technology.

Further discussion of the regulatory basis for this determ ination can be found in the MPCA’s December 2009 Regional Haze State Implementation Plan submittal, in Appendix 9.3.

2.2 Affected Units

The units for which the MPCA must determine BART and estab lish emission limits consistent with that determination

are:

Emission Unit Name EU Number 1 

### Control Equipment and Stack Numbers Line 3 Indurating Furnace EU225 CE146/SV103 Line 4 Indurating Furnace EU261 CE103/SV118 Line 5 Indurating Furnace EU282 CE113/SV127 Line 6 Indurating Furnace EU315 CE126/SV144 Line 7 Indurating Furnace EU334 CE136/SV151

2.3 The BART Determination

The MPCA’s BART determinations for these units are docume nted in Appendix 9.3 of the December 2009 Regional Haze SIP submittal.

The NO X 

### BART determination for the five indurating furnaces is generally good combustion practices. This is coupled with low-NO X 

### burners in the pre-heat zone and fuel blending for Lines 4, 5, 6, and 7. Low NO X 

### burners were installed on Line 6 in 2006, Line 7 in 2008, and Lines 4 and 5 in 2009. Fuel blending on Line 3 is also part of the BART determination for that unit.

However, due to the lack of sufficient emissions data repr esenting the range of operating conditions that influence emissions, the MPCA did not set a NO X 

### emission limit at the time of making the BART determination for the indurating furnaces. Instead, the MPCA and Minntac entered into an Administrative Order, under which Minntac agreed to install and maintain Continuous Emissions Monitoring Systems (CEMS) on all five lines and provide NO X 

### emission information to the MPCA.

The SO 2 

### BART determination for the indurating furnaces is operation of existing controls. In the initial Regional Haze SIP, the MPCA set a corresponding SO 2 

### emission limit for Lines 3, 4, and 5, as these lines are natural gas and biomass fired and the SO 2 

### emissions come primarily from the ore. However, as with NO X 

### , additional emission information was needed prior to setting an SO 2 

### limit from the coal-fired Lines 6 and 7. Minntac agreed in an Administrati ve Order to install and maintain SO 2 

### CEMS on these lines and provide emission informatio n to the MPCA. In addition, Minntac has installed SO 2 

### CEMS on Lines 3, 4, and 5. After reviewing all the data, at the request of Minntac, the MPCA determined to reevaluate the limits for SO 2 

### on Line 3, 4, and 5.

1 The MPCA organizes conditions and illustrates associations in its permits using the Emission Un it (EU), Control Equipment (CE ), and Stack/Vent (SV) numbers.

### 2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NO X 

### and SO 2 

### emission information from all five in durating furnaces provided by Minntac.

NO X 

### emission data was received beginning in October 2007 and SO 2 

### emission data beginning in July 2008. The MPCA’s review focused on the most recent data, from the end of August 2009 through the end of March 2011. Each line had a slightly different start date for the data that was analyzed. This difference is due to the high number of zero or very low values for NO X 

### emissions recorded through the spring and summer mo nths of 2009. The data to analyze was determined by picking a start date that would allow the calculation of a 30-day rolling average that did not include these large areas of zero values. SO 2 

### emissions were then looked at over the same time frame.

The following graph shows the variation in NO X 

### emissions over the analyzed time frame.

The following table shows descriptive statistics of the NO X 

### emissions for each line, in tons per day.

Minntac NO X 

### Emissions Descriptive Statistics ( 30 day rolling average, tons per day) Line 3 NO X 

### Line 4 NO X 

### Line 5 NO X 

### Line 6 NO X 

### Line 7 NO X 

### # Data Points 526 545 549 566 587 Minimum 0.000 0.02 2.23 3.18 1.19 Mean 2.92 5.27 5.20 4.57 3.01 Std Deviation 1.62 1.82 1.43 1.00 1.08 Median 2.74 4.78 4.874 4.51 2.70 Maximum 8.19 10.06 9.136 7.13 5.18 0 3 6 9 12

8/1/09 10/30/09 1/28/10 4/28/10 7/27/10 10/25/10 1/23/11 4/23/11 

### NOx (ton/day; 30-day rolling average) @USS Minntac from CEMS

L3 NOx

L4 NOx

L5 NOx

L6 NOx

L7 NOx

### The following graphs show the variation in SO 2 

### emissions for all lines over the analyzed time frame.

The following table shows descriptive statistics of the SO 2 

### emissions for Lines 6 and 7, in tons per day

Minntac SO 2 

### Emissions Descriptive Statistics (30 day rolling average, tons per day)

Line 3 Line 4 Line 5 Line 6 Line 7 # Data Points 526 545 549 565 587 Minimum 0.00 0.00 0.29 0.27 0.14 Mean 0.66 0.58 0.80 0.70 0.67 Std Deviation 0.37 0.22 0.17 0.31 0.35 Median 0.77 0.58 0.77 0.60 0.58 Maximum 1.27 1.09 1.21 1.36 1.55

The most recent data for each line and each pollutant was plotted to the most appr opriate statistical probability distribution, and a 99% confidence interval was constructed. The limit was based on the 99% upper prediction level.

The MPCA has determined that the appropriate BART NO X 

### limits are

Line NO X 

### BART Limit in Tons/Day 3 7.85 4 9.85 5 9.46 6 7.14 7 5.51 0.0 0.4 0.8 1.2 1.6

8/1/09 10/30/09 1/28/10 4/28/10 7/27/10 10/25/10 1/23/11 4/23/11 

### SO 2 

### (ton/day; 30-day rolling average) at USS Minntac from CEMS

L3 SO2

L4 SO2

L5 SO2

L6 SO2

L7 SO2

### And the appropriate BART SO 2 

### Limits are:

Line SO 2 

### BART Limit in Tons/Day 3 1.28 4 1.10 5 1.10 6 1.47 7 1.61

All of these limits are on a 30-day rolling average basis. Co mpliance is to be determined through continued operation of the CEMS.Proposed BART Limits: NOx (ton/day) calculated as a 30-day rolling average Line 3 Line 4 Line 5 Line 6 Line 7 Data Used 10/29/09 - 3/31/11 10/03/09 - 03/31/11 09/29/09 - 03/31/11 9/12/09 - 03/31/11 08/22/09 - 3/31/11 NOx Limit 7.85 9.85 9.46 7.14 5.51 tons/day 99%-tile of the distribution 3-p Weibull Weibull Lognormal Gamma Normal

c.f. Max 8.19 10.06 9.14 7.13 5.18 based on the data of recent rows 683 838 761 594 432 uniform emission rate, lb/hr

Limit/Max 95.8% 97.9% 104% 100% 106% Count 526 545 549 566 587

Proposed BART Limits: SO2 (ton/day) calculated as a 30-day rolling average Line 3 Line 4 Line 5 Line 6 Line 7 SO2 Limit 1.28 1.10 1.19 1.47 1.61 tons/day 99%-tile of the distribution Small Extreme Value Normal Normal Weibull Weibull

c.f. Max 1.27 1.09 1.21 1.36 1.55 based on the data of recent rows 106 91 101 113 129 uniform emission rate, lb/hr

Limit/Max 101% 101% 98% 108% 104% Count 526 545 549 566 587

0.0 0.4 0.8 1.2 1.6

8/1/09 10/30/09 1/28/10 4/28/10 7/27/10 10/25/10 1/23/11 4/23/11

SO2 (ton/day; 30-day rolling average) at USS Minntac from CEMS

L3 SO2

L4 SO2

L5 SO2

L6 SO2

L7 SO2 0 3 6 9 12

8/1/09 10/30/09 1/28/10 4/28/10 7/27/10 10/25/10 1/23/11 4/23/11

NOx (ton/day; 30-day rolling average) @USS Minntac from CEMS

L3 NOx

L4 NOx

L5 NOx

L6 NOx

L7 NOx

### Supporting Plots

NO X 

### Recent Data - L3: 10/22/2009-3/31/2011

NO X 

### Recent Data - L4: 10/3/2009-3/31/2011

### NO X 

### Recent Data - L5: 9/29/2009-3/31/2011

NO X 

### Recent Data - L6: 9/12/2009-3/31/2011

### NO X 

### Recent Data - L7: 8/22/2009-3/31/2011

SO 2 

### Recent Data – L3

-

### SO 2 

### Recent Data – L6

SO 2 

### Recent Data – L7

### Supporting Derived Values

### Appendix 2: BART Administrative Orders

### -DRAFT1 

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER ArcelorMittal – Minorca Mine Inc.

This Administrative Order (Order) is issued by the Minnesota Pollution Control Agency (MPCA) to ArcelorMittal Minorca Mine, Inc (Arcelor) purs uant to Minn. Stat. § 116.07, subd. 9 (2011).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its mandatory Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants contributing to re gional haze are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

### -DRAFT2 

### 6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided Arcelor and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. ArcelorMittal Minorca Mine Inc. (Arcelor) owns and operates a mine and taconite pellet production plant at its facility (“Facility”) located near Virgin ia, Minnesota. Arcelor makes fully fluxed pellets using one straight grate indurating furnace. Th e furnace burns a maximum of 370 MMBtu/hr of natural gas and is capable of handling 400 tons of pellets per hour. The Facility has three main areas where emissions are created: the mine, the tailings basin, and the pellet plant. The larger sources of regulated air emissions at Arcelor are the induratin g furnace operations and the mining activities, with lesser amounts from other processing operations and fugitive dust sources, including haul roads and the tailings basin.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

8. The Rule includes 40 CFR § 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

9. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. [40 CFR § 51.308(e)(ii)].

10. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

11. The Facility includes units that are subject to BART. See RESULTS of Best Available Retrofit Technology (BART) Modeling to Determine Sour ces Subject-to-BART in the State of Minnesota at http://proteus.pca.state.mn.us/publications/aq-sip2-07.pdf

.

12. Arcelor has one unit, the indurating furnace identified as Emission Unit 026 in Air Emissions Permit No. 13700062-003, that is subject-to-B ART and for which Arcelor performed a BART analysis. This

### -DRAFT3 

### unit has four stack vents. The stack vents asso ciated with the unit are SV014, SV015, SV016, and SV017.

13. MPCA determined and Arcelor ag reed that its indurating furnace (EU026) is subject-to-BART.

14. The MPCA determined that BART for this unit consists of:

a. Operation of the existing wet scrubber to control SO 2 

### emissions; and

b. Good combustion practices and operation of low NO X 

### burners in the pre-heat zone to control NO X 

### emissions; and

c. Implementation of the taconite Maximum Achievable Control Technology (MACT) standard to control PM emissions. [40 CFR § 63, Subp. RRRRR].

15. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302 (c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish the BART emission limit for Arcelor.

LONG-TERM STRATEGY

16. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

17. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

18. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including Arcelor, is their demonstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 50.17] and nitrogen dioxide (NO 2 

### ) [40 CFR § 50.11]. As a result, Arcelor must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for Arcelor will be completed.

ORDER

NOW, THEREFORE, ARCELOR IS ORDERED:

19. To install and operate any necessary control equipment or undertake any necessary work practices to meet the following requirements, which represent BART for Arcelor.

I. BART Emission Limitation s and Compliance Methods

a. BART for NO X

### -DRAFT4 

### i. Emission Limitations

1. NO X 

### emissions from EU026 shall not exc eed 1018.0 lbs/hour at all times that EU026 is operating, measured on a 30-day rolling average.

2. Hours during which EU026 does not op erate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

3. The NO X 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. Arcelor must demonstrate compliance with the NO X 

### emission limit above as follows:

1. NO X 

### stack testing, with simultaneous measurement of emissions from all four stacks for 30 hourly data poin ts, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART NO X 

### performance test. Within 12 months of the date that the emissions limit becomes e ffective, Arcelor shall conduct a performance test to demonstrate compliance with the BART limit for NO X 

### emissions.

b. Annual BART NO X 

### performance tests. Each calendar year after the initial test, Arcelor shall conduct a performance test to demonstrate compliance with the BART limit for NO x 

### emissions. The performance test shall be conducted annually within two months of the anniversary date of the initial BART NO x 

### performance test.

c. Performance tests shall be conducted using methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

2. As an alternative to the stack testing required in part 1, Arcelor may install and operate continuous emission monitoring systems (CEMS) to demonstrate compliance on a continuous basis. CEMS shall be operated in accordance with Minn. R. 7017. 1002 through Minn. R. 7017.1220. Once CEMS are installed and certified, compliance must be determined through use of CEMS.

b. BART for SO 2



### i. Emission Limitations

1. SO 2 

### emissions from EU026 shall not exceed 0.165 lbs per long ton of pellets produced at all times that EU026 is operating, measured on a 30-day rolling average basis.

### -DRAFT5 

### 2. Hours during which EU026 does not op erate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

3. The limit applies only when the company is burning natural gas.

4. The SO 2 

### emission limit is effective on and after the date six months after the effective date of EPA’s appro val of this BART determination.

ii. Arcelor must demonstrate compliance with the SO 2 

### emission limit above as follows:

1. SO 2 

### stack testing, with simultaneous measurement of emissions from all four stacks for 30 hourly data poin ts, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART SO 2 

### performance test. Within 12 months of the date that the emissions limit becomes e ffective, Arcelor shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions.

b. Annual BART SO 2 

### performance tests. Each calendar year after the initial test, Arcelor shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions. Each performance test shall be conducted annually within two months of the anniversary date of the initial BART SO 2 

### performance test.

c. Performance tests shall be conducted using methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

d. The initial performance test shall also establish the minimum scrubber pressure drop and water flow rate. Arcelor may propose to change the rates following a subsequent performance test pursuant to an approved performance test plan, but must obtain MPCA authorization before implementing a proposed change.

2. Operate and maintain a continuous pa rametric monitoring system (CPMS) to measure and record the daily average scrubber pressure drop and the daily average scrubber water flow ra te, to demonstrate that the levels remain at or above the minimum leve ls established during the initial and subsequent performance tests.

### -DRAFT6 

### i. Arcelor shall not use data recorded during monitor malfunctions, associated repairs, and required quality assurance or control activiti es in data averages and calculations used to report emission or operating levels, or to fulfill a minimum data availability requirement. Arcelor shall use all the data collected during all other periods in assessing compliance. A monitoring malfunction is any sudden, infrequent, not reasonably preventable failure of the monitoring system to provide valid data. Monitoring failures that are caused in whole or in part by poor maintenance or careless operation are not considered malfunctions.

3. As an alternative to the stack testing required in part 1, Arcelor may install and operate continuous emission monitoring systems (CEMS) to demonstrate compliance on a continuous basis. CEMS shall be operated in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.Once CEMS are installed and certified, compliance must be determined through the use of CEMS.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissi ons from EU026 shall not exceed 0.01 gr/dscf at all times that EU026 is operating.

ii. Arcelor must demonstrate compliance with the PM emission limits above using the compliance methods in 40 CFR 63 Subpart RRRRR, the taconite MACT, based on the flow weighted mean concentration of all four stacks associated with EU026.

iii. Compliance with the PM emission limit must be demonstrated by the deadlines laid out in 40 CFR 63 Subpart RRRRR.

II. Recordkeeping and Reporting

a. Recordkeeping. Arcelor shall maintain electronic files of all information required by this Order in a form suitable for determination of Arcelor’s compliance with this Order by EPA or MPCA staff and readily available for EPA or MPCA inspection and review.

i. Permanent Records: Arcelor shall perman ently maintain the following information together with all amendments , revisions, and modifications to this information.

1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

### -DRAFT7 

### ii. Non Permanent Records: Arcelor shall ma intain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facility requirements of Arcelor’s air emissions permit, pursuant to Minn. R. 7007.0800 and. Arcelor shall retain the records for a minimum of five years following the date on which the record was generated. The most recent two years of info rmation must be kept on site

.

b. Reporting. Arcelor shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

20. To conduct the following modeling analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling Protocol

a. By April 1, 2012, submit to the MPCA a mode ling protocol for the Arcelor facility for NO 2 

### emissions. The protocol must be submitted using MPCA’s most recent model protocol forms, AQDMP-01 and AQDMPS-01.

II. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### NAAQS (40 CFR 50.17) and one-hour NO 2 

### NAAQS (40 CFR 50.11);

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

General.

21. Nothing in this Order shall relieve Arcelor of its obligation to meet permitting requirements for any physical or operational ch ange at its facility.

22. This Order is not transferable or assignable to an y person without the express written approval of the MPCA.

23. This Order is effective upon the date that it is signed by the MPCA Commissioner or his designee.

### -DRAFT8 

### RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

IT IS SO ORDERED.

Minnesota Pollution Control Agency

______________________________________ Paul W. Aasen Commissioner

### -DRAFT1 

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER Hibbing Taconite Company

This Administrative Order (Order) is issued by the Minnesota Pollution Control Agency (MPCA) to Hibbing Taconite Company (HTC) pursuant to Minn. Stat. § 116.07, subd. 9 (2000).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

### -DRAFT2 

### 6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided HTC and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. Hibbing Taconite Company (HTC) is a taconite (magnetite) ore mining and beneficiation facility (“Facility) located in Hibbing, Minnesota. HTC is owned by ArcelorMittal, C liffs Natural Resources, and US Steel; Cliffs Natural Resources is the ma naging agent. HTC operates three functionally equivalent straight grate indurating furnaces, whic h are capable of producing a combined 9 million dry tons of pellets annually. The larger sources of air emissions at HTC are from the mining activities and indurating furnace operations, with lesser amounts from other processing operations and fugitive dust sources, including haul roads and the tailings basin.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

8. The Rule includes 40 CFR § 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

9. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. [40 CFR § 51.308(e)(ii)].

10. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

11. The Facility includes units that are subject to BART. See RESULTS of Best Available Retrofit Technology (BART) Modeling to Determine Sour ces Subject-to-BART in the State of Minnesota at http://proteus.pca.state.mn.us/publications/aq-sip2-07.pdf

.

12. HTC has three units, the pelletizing furnaces identified as Emissi on Units 020, 021 and 022 in Air Emissions Permit No. 13700061-004, that are subjec t-to-BART and for which HTC performed a BART analysis. Each unit has four stack vents. The stack vents associated with EU020, the Line 1 pelletizing furnace, are SV021, SV022, SV023 and SV024. The st ack vents associated with EU021, the Line 2

### -DRAFT3 

### pelletizing furnace, are SV025, SV 026, SV027, and SV028. The stack vents associated with EU022, the Line 3 pelletizing furnace, ar e SV029, SV030, SV031, and SV032.

13. MPCA and HTC agreed that its three pelletizing furnaces (EU020, EU021, a nd EU022) are subject-toBART.

14. The MPCA determined that BART for these units consists of

a. Operation of the existing wet scrubber to control SO 2 

### emissions; and

b. Good combustion practices to control NO X 

### emissions; and

c. Implementation of the taconite Maximum Achi evable Control Technology (MACT) standard to control PM emissions. [40 CFR § 63, Subp. RRRRR].

15. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302 (c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish th e BART emission limit for HTC.

LONG-TERM STRATEGY

16. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

17. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

18. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including HTC, is their de monstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 50.17] and nitrogen dioxide (NO 2 

### ) [40 CFR § 50.11]. As a result, HTC must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for HTC will be completed.

ORDER

NOW, THEREFORE, HTC IS ORDERED:

19. To install and operate any necessary control equipment or undertake any necessary work practices in order to meet the following requirements, which represent BART for HTC.

I. BART Emission Limitation s and Compliance Methods

a. BART for Nitrogen Oxides (NO X 

### )

### -DRAFT4 

### i. Emission Limitations

1. NO X 

### emissions from Line 1, EU020, shall not exceed 447.4 lbs/hour at all times that EU020 is operating, me asured on a 30-day rolling average;

2. NO X 

### emissions from Line 2, EU021, shall not exceed 571.7 lbs/hour at all times that EU021 is operating, meas ured on a 30-day rolling average;

3. NO X 

### emissions from Line 3, EU022, shall not exceed 338.3 lbs/hour at all times that EU022 is operating, me asured on a 30-day rolling average.

4. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

5. These NO X 

### emission limits are effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. HTC must demonstrate compliance with the NO X 

### emission limits above as follows:

1. NO X 

### stack testing with si multaneous measurement of emissions from all four stacks for 30 hourly data poin ts, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART NO X 

### performance test. Within 12 months of the date that the limit becomes effective, HTC shall conduct a performance test to demonstrate compliance with the BART limit for NO X 

### emissions.

b. Annual BART NO X 

### performance tests. Each calendar year after the initial test, HTC shall conduct a performance test to demonstrate compliance with the BART limit for NO x 

### emissions. The performance test shall be conducted between 10 months and 14 months after the previous BART NO x 

### performance test.

c. Performance tests shall be conducted using test methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval, based on representative performance of the affected source.

b. As an alternative to the stack testing requi red in part 1, HTC may install and operate continuous emission monitoring systems (CEMS) to demonstrate compliance on a continuous basis. CEMS shall be operated in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220. Once CEMS are installed and certified, compliance must be determined through the use of CEMS.BART for Sulfur Dioxide (SO 2 

### )

### -DRAFT5 

### i. Emission Limitations

1. SO 2 

### emissions from Line 1, EU020, shall not exceed 0.207 lbs SO 2 

### /long ton of pellets fired (finished) at all time s that EU020 is operating, measured on a 30-day rolling average;

2. SO 2 

### emissions from Line 2, EU021, shall not exceed 0.207 lbs SO 2 

### /long ton of pellets fired (finished) at all time s that EU021 is operating, measured on a 30-day rolling average;

3. SO 2 

### emissions from Line 3, EU022, shall not exceed 0.207 lbs SO 2 

### /long ton of pellets fired (finished) at all time s that EU022 is operating, measured on a 30-day rolling average.

4. Each limit applies only when the company is burning natural gas.

5. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

6. These SO 2 

### emission limits are effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. HTC must demonstrate compliance with the SO 2 

### emission limits as follows:

1. SO 2 

### stack testing, with simultaneous measurement of emissions from all four stacks for 30 hourly data poin ts, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART SO 2 

### performance test. Within 12 months of the date that the emissions limit becomes effective, HTC shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions.

b. Annual BART SO 2 

### performance tests. Each calendar year after the initial test, HTC shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions. The performance test shall be conducted between 10 months and 14 months after the previous BART SO 2 

### performance test.

c. Performance tests shall be conducted using test methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

### -DRAFT6 

### d. The initial performance test shall also establish the minimum scrubber pressure drop and water flow rate. HTC may propose to change the rates following a subse quent performance test pursuant to an approved performance test plan, but must obtain MPCA authorization before implementing a proposed change.

2. Operate and maintain a continuous pa rametric monitoring system (CPMS) to measure the daily average scrubber pressure drop and the daily average scrubber water flow rate, to demonstrate that the levels remain at or above the minimum levels established during the initial and subsequent performance tests.

i. HTC shall not use data recorded during monitoring malfunctions, associated repairs, and required quality assurance or control activiti es in data averages and calculations used to report emission or operating levels, or to fulfill a minimum data availa bility requirement. HTC shall use all the data collected during all other periods in assessing compliance. A monitoring malfunction is any sudden, infrequent, not reasonably preventable failure of the monitoring system to provide valid data. Monitoring failures that are caused in part by poor maintenance or careless operation are not considered malfunctions.

3. As an alternative to the stack testing la id out in part 1, HTC may install and operate continuous emission monitori ng systems (CEMS) to demonstrate compliance on a continuous basis.

a. Once CEMS are installed and certified, compliance must be determined through the use of CEMS.

b. CEMS shall be operated in a ccordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

iii. Compliance with these limits must be demonstrated by six months after the effective date of EPA’s approval of this BART determination.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissions from Line 1, EU020, shall not exceed 0.01 gr/dscf at all times EU020 is operating; and

2. Filterable (front-half) PM emissions from Line 2, EU021, shall not exceed 0.01 gr/dscf at all times EU021 is operating; and

3. Filterable (front-half) PM emissions from Line 3, EU022, shall not exceed 0.01 gr/dscf at all times EU022 is operating.

### -DRAFT7 

### ii. Compliance with the PM emission limits above will be determined using the compliance methods laid out 40 CFR 63 Subpart RRRRR, the taconite MACT, and determined based on the flow weighted mean concentration of all stacks associated with the subject emission unit.

iii. Compliance with the PM emission limit must be demonstrated by the deadlines laid out in the taconite MACT.

II. Installation of Continuous Emission Monitoring Systems (CEMS)

a. Within 60 days of the effective date of this Order, HTC shall submit to the MPCA a Plan which provides a schedule for the installation of one SO 2 

### and one NO X 

### CEMS on the Line 2 pelletizing furnace, EU021, measuring emissi ons from SV025, SV026, SV027, and SV028. The Plan shall provide that each CEMS is installe d and certification test results that report certification are submitted to the MPCA no later than one year after the due date of the Plan.

b. HTC shall conform to the CEMS requiremen ts specified in Minn. R. chs. 7017.1002, 7017.1030, 7017.1035, 7017.1040, 7017.1050, 7017.1060, 7017.1070, 7017.1080, 7017.1090, 7017.1100, 7017.1110, 7017.1120, subps. 2, 3, and 4, 7017.1130, 7017.1140, 7017.1150, 7017.1160, 7017.1170 and 7017.1180.

c. Once installed, HTC shall continuously operate the CEMS under this Order at all times when the associated process equipment is operating.

d. Once installed and certified, the CEMS shall be used to determine compliance with the Line 2 pelletizing furnace NO X 

### emissions limit shown in Part 1.a.i and SO 2 

### emissions limit shown in Part I.b.i of this Order.

III. Recordkeeping and Reporting

a. Recordkeeping. HTC shall maintain electronic fi les of all information required by this Order in a form suitable for determination of HTC’ s compliance with this Order by U.S. EPA or MPCA staff and readily available for U.S. EPA or MPCA inspection and review.

i. Permanent Records: HTC shall permanentl y maintain the following information together with all amendments , revisions, and modifications to this information.

1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

ii. Non Permanent Records: HTC shall maintain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facility requirements of HTC’s air emissions permit, pursuant to Minn. R. 7007.0800 and. HTC shall retain the records for a minimum of five years following the date on which the record was generated. The most recent two years of info rmation must be kept on site

.

### -DRAFT8 

### b. Reporting. HTC shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

20. To conduct the following modelin g analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling Protocol

a. By April 1, 2012, submit to the MPCA a modeling protocol for the HTC for NO 2 

### emissions. The protocol must be submitted using MPCA’smost recent model protocol forms, AQDMP01 and AQDMPS-01.

II. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

General.

21. Nothing in this Order shall relieve HTC of its obligation to meet permitting requirements for any physical or operational ch ange at its facility.

22. This Order is not transferable or assignable to any person without the express written approval of the MPCA.

23. This Order is effective upon the date that it is signed by the MPCA Commissioner or his designee.

### -DRAFT9 

### RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

IT IS SO ORDERED.

Minnesota Pollution Control Agency

______________________________________ Paul W. Aasen Commissioner

### -DRAFT1 

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER Northshore Mining Company – Silver Bay

This Administrative Order (Order) is issued by the Minnesota Pollution Control Agency (MPCA) to Northshore Mining Company – Silver Bay (NSM) pursuant to Minn. Stat. § 116.07, subd. 9 (2000).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its mandatory Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants contributing to re gional haze are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

### -DRAFT2 

### 6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided NSM and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. Northshore Mining Company – Silver Bay (NSM) is lo cated on the north shore of Lake Superior. It was the first taconite operation in Minnesota, originally built in the mid-1950s by Reserve Mining Company. Cleveland Cliffs, Incorporated purchased th e facility from Cyprus Minerals in 1994; Cliffs Natural Resources now owns and operates the facility.

8. NSM has four indurating furnaces. Furnaces 11 and 12 began operating in 1963. Furnaces 11 and 12 were manufactured by Arthur G. McKee and are NS M’s largest indurating furnaces. They each burn a maximum of 150 MMBtu/hr of natural gas and are capable of processing 300 tons of pellets per hour. The other two furnaces, Furance 5 and Furnace 6, began operation prior to 1962. Furnace 5 was shut down for several years; in 2006, NSM re ceived a Prevention of Significant Deterioration permit authorizing the restarting of Furnace 5.

9. NSM also operates two process boilers. Both proce ss boilers were installed in 1965 and are rated at 79 MMBtu/hr. The boilers are capable of burning fuel oil and natural gas.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

10. The Rule includes 40 CFR 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

11. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. (40 CFR 51.308(e)(ii).)

12. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

### -DRAFT3 

### 13. The facility includes units that are subject to BAR T. See RESULTS of Best Available Retrofit Technology (BART) Modeling to Determine Sour ces Subject-to-BART in the State of Minnesota at http://proteus.pca.state.mn.us/publications/aq-sip2-07.pdf

.

14. NSM has four units, the indurating furnaces id entified as Emission Units 100/104, and 110/113 and the process boilers identified as Emission Units 003 and 004 in Air Emissions Permit No. 07500003- 007, that are subject-to-BART and for which NS M performed a BART analysis. The stack vents associated with Furnace 11, EU100/EU104, are SV101, SV102, SV103, SV104, and SV105. The stack vents associated with Furnace 12, EU110/EU114, are SV111, SV112, SV113, SV114, and SV115. The stack vent associated with proc ess boiler #1, EU003, is SV003. Th e stack vent associated with process boiler #2, EU004, is SV003.

15. MPCA determined and NSM agreed that two of NSM’s indurating furnaces (Furnace 11 and Furnace 12) and two of NSM’s process boilers (boile r #1 and boiler #2) are subject-to-BART.

16. The MPCA determined that BART for th e indurating furnaces consists of

a. Operation of the existing wet scrubber to control SO 2 

### emissions;

b. Good combustion practices to control NO X 

### emissions; and

c. Implementation of the taconite Maximum Achi evable Control Technology (MACT) standard to control PM emissions. [40 CFR § 63, Subp. RRRRR].

17. The MPCA determined that BART for the process boilers consists of existing design and permitted fuels.

18. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302(c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish th e BART emission limit for NSM.

LONG-TERM STRATEGY

19. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

20. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

21. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including NSM, is their demonstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 51.17] and nitrogen dioxide (NO 2 

### ) [40 CFR § 51.11]. As a result, NSM must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for NSM will be completed.

### -DRAFT4 

### ORDER

NOW, THEREFORE, NSM IS ORDERED:

22. To install and operate any necessary control equipment or undertake any necessary work practices in order to meet the following requirements, which represent BART for NSM.

I. Process Boiler BART Emission Limi tations and Compliance Methods

a. BART for NO X



### i. Emission Limitations

1. NO X 

### emissions from Process Boiler #1 (EU003) shall not exceed 0.17 lbs/hour at all times when EU003 is op erating, measured on a 30-day rolling average.

2. NO X 

### emissions from Process Boiler #2 (EU004) shall not exceed 0.17 lbs/hour at all times when EU004 is op erating, measured on a 30-day rolling average.

3. Hours during which the unit does no t operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

4. The NO X 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. NSM must demonstrate compliance with the NO X 

### emission limits above will as follows:

1. NO X 

### stack testing, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART NO X 

### performance test. Within 12 months of the date that the emissions limit becomes effective, NSM shall conduct a performance test to demonstrate compliance with the BART limit for NO X 

### emissions.

b. BART NO X 

### performance tests. NSM shall conduct a performance test to demonstrate compliance with the BART limit for NO x 

### emissions once every five years.

c. Performance tests shall be conducted using methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

### -DRAFT5 

### II. Furnace BART Emission Limita tions and Compliance Methods

a. BART for NO X



### i. Emission Limitations

1. NO X 

### emissions from Furnace 11 shall not exceed 115.5 lbs/hour as all times when Furnace 11 is operating, measured on a 30-day rolling average;

2. NO X 

### emissions from Furnace 12 shall not exceed 115.5 lbs/hour at all times when Furnace 12 is operating, measured on a 30-day rolling average.

3. Hours during which the emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

4. The NO X 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. NSM must demonstrate compliance with the NO X 

### emission limits above as follows:

1. NO X 

### stack testing, with simultaneous measurement of emissions from all four stacks for 30 hourly data poin ts, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART NO X 

### performance test. Within 12 months of the date that the limit becomes effective, NSM shall conduct a performance test to demonstrate compliance with the BART limit for NO X 

### emissions.

b. Annual BART NO X 

### performance tests. Each calendar year after the initial test, NSM shall conduct a performance test to demonstrate compliance with the BART limit for NO x 

### emissions. The performance test shall be conducted between 10 months and 14 months after the previous BART NO x 

### performance test.

c. Performance tests shall be conducted using methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

a. As an alternative to the stack test ing laid out in part 1, NSM may install and operate continuous emi ssion monitoring systems (CEMS) to demonstrate compliance on a co ntinuous basis. CEMS shall be operated in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220. Once CEMS are installed and certified, compliance must be determined through the use of CEMS.

### -DRAFT6 

### b. BART for Sulfur Dioxide (SO 2 

### )

i. Emission Limitations

1. SO 2 

### emissions from Furnace 11 shall not exceed 0.0651 lbs SO 2 

### /long ton of pellets fired (finished), measured on a 30-day rolling average;

2. SO 2 

### emissions from Furnace 12 shall not exceed 0.0651 lbs SO 2 

### /long ton of pellets fired (finished), measured on a 30-day rolling average.

3. This limit applies only wh en the subject emission unit is burning natural gas.

4. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

5. The SO 2 

### emissions limits are effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. Compliance with the SO 2 

### emission limits above will be determined as follows:

1. Annual SO 2 

### stack testing, with simultan eous measurement of emissions from all four stacks for 30 hourly data points, conducted in compliance with Minn. R. 7017.2001 through Minn. R. 7017.2060.

a. Initial BART SO 2 

### performance test. Within 12 months of the date that the limit becomes effective, NSM shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions.

b. Annual BART SO 2 

### performance tests. Each calendar year after the initial test, NSM shall conduct a performance test to demonstrate compliance with the BART limit for SO 2 

### emissions. The performance test shall be conducted between 10 months and 14 months after the previous BART SO 2 

### performance test.

c. Performance tests shall be conducted using methodology and under such conditions as the Commissioner specifies in the Commissioner’s test plan approval.

d. The initial performance test shall also establish the minimum scrubber pressure drop and water flow rate. NSM may propose to change the rates following a subse quent performance test pursuant to an approved performance test plan, but must obtain MPCA authorization before implementing a proposed change.

### -DRAFT7 

### 2. Operate and maintain a continuous pa rametric monitoring system (CPMS) to measure the daily average scrubber pressure drop and the daily average scrubber water flow rate, to demonstrate that the levels remain at or above the minimum levels established during the initial and subsequent performance tests.

i. NSM shall not use data recorded during monitoring malfunctions, associated repairs, and required quality assurance or control activiti es in data averages and calculations used to report emission or operating levels, or to fulfill a minimum data availability requirement. NSM shall use all the data collected during all other periods in assessing compliance. A monitoring malfunction is any sudden, infrequent, not reasonably preventable failure of the monitoring system to provide valid data. Monitoring failures that are caused in part by poor maintenance or careless operation are not considered malfunctions.

3. As an alternative to the stack testing la id out in part 1, NSM may install and operate continuous emission monitori ng systems (CEMS) to demonstrate compliance on a continuous basis. CEMS shall be operated in accordance with Minn. R. 7017.1002 through Minn . R. 7017.1220. Once CEMS are installed and certified, compliance must be determined through the use of CEMS.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissi ons from EU100 shall not exceed 0.01 gr/dscf at all times when EU100 is operating;

2. Filterable (front-half) PM emissi ons from EU104 shall not exceed 0.01 gr/dscf at all times when EU104 is operating;

3. Filterable (front-half) PM emissi ons from EU110 shall not exceed 0.01 gr/dscf at all times when EU110 is operating; and

4. Filterable (front-half) PM emissi ons from EU114 shall not exceed 0.01 gr/dscf at all times when EU1114 is operating.

ii. Compliance with the PM emission limits above will be determined using the compliance methods laid out in 40 CFR 63 Subpart RRRRR, the taconite MACT, and determined based on the flow weighted mean concentration of all stacks for the furnace.

iii. Compliance with the PM emission limit must be demonstrated by the deadlines laid out in the taconite MACT.

### -DRAFT8 

### III. Recordkeeping and Reporting

a. Recordkeeping. NSM shall maintain electronic files of all information required by this Order in a form suitable for determination of NSM’ s compliance with this Order by U.S. EPA or MPCA staff and readily available for U.S. EPA or MPCA inspection and review.

i. Permanent Records: NSM shall permanen tly maintain the following information together with all amendments , revisions, and modifications to this information.

1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

ii. Non Permanent Records: NSM shall retain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facili ty requirements of NSM’s ai r emissions permit, pursuant to Minn. R. 7007.0800 and. NSM shall reta in the records for a minimum of five years following the date on which the record was generated. The most recent two years of information must be kept on site

.

b. Reporting. NSM shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

23. To conduct the following modeling analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling Protocol

a. By April 1, 2012, submit to the MPCA a modeling protocol for the NSM facility for NO 2 

### emissions. The protocol must be submitted using MPCA’s most recent model protocol forms, AQDMP-01 and AQDMPS-01.

II. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

### -DRAFT9 

### General.

24. Nothing in this Order shall relieve NSM of its ob ligation to meet permitti ng requirements for any physical or operational ch ange at its facility.

25. This Order is not transferable or assignable to any person without the express written approval of the MPCA.

26. This Order is effective upon the date that it is signed by the MPCA Commissioner or his designee.

RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

IT IS SO ORDERED.

Minnesota Pollution Control Agency

______________________________________ Paul W. Aasen Commissioner

### -DRAFTSTATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER United Taconite, LLC

This Administrative Order (Order) is issued by the Minnesota Pollution Control Agency (MPCA) to United Taconite, LLC (United) pursuant to Minn. Stat. § 116.07, subd. 9 (2011).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its mandatory Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants contributing to re gional haze are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

### -DRAFT6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided United and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. United produces taconite pellets at its facility (h erein referred to as “Facility”) located near Forbes, Minnesota. This facility has two indurating Allis-Chalm ers furnaces. Line 1 is the smaller of the two, with a rated throughput of 280 tons of pellets per hour and a heat input of 190 MMBtu per hour of natural gas. The newer line, Line 2, is rated at 672 tons per hour with a heat input from natural gas, coal, petroleum coke, and othe r fuels of 400 MMBtu per hour.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

8. The Rule includes 40 CFR 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

9. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. [40 CFR § 51.308(e)(ii)].

10. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

11. The United facility includes two units (EU 040 and EU042) that are subject to BART. See RESULTS of Best Available Retrofit Technology (BART) Modeli ng to Determine Sources Subject-to-BART in the State of Minnesota at http://proteus.pca.state.mn.us/publications/aq-sip2-07.pdf

.

12. United’s two pellet furnaces, Line 1 (EU040 with SV046) and Line 2 (EU042 with SV048 and SV049), were determined to be subject-to-BART and for which a BART analysis was performed.

13. MPCA determined and United agreed that the pe llet furnaces (EU040 an d EU042) are subject-toBART.

14. The MPCA determined that BART for this unit consists of

### -DRAFTa. Operation of the existing wet scrubber and use of appropriate fuel blends to control SO 2 

### emissions;

b. Good combustion practices, along with ex isting combustion controls to control NO X 

### emissions; and

c. Implementation of the taconite Maximum Achi evable Control Technology (MACT) standard to control PM emissions. [40 CFR § 63, Subp. RRRRR].

15. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302(c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish th e BART emission limit for United.

LONG-TERM STRATEGY

16. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

17. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

18. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including United, is their demonstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 50.17] and nitrogen dioxide (NO 2 

### ) [ 40 CFR § 50.11]. As a result, Un ited must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for United will be completed.

ORDER

NOW, THEREFORE, IT IS ORDERED AND AGREED:

19. United will install and operate any necessary co ntrol equipment or undertake any necessary work practices to meet the following requirem ents which represent BART for United.

I. BART Emission Limitation s and Compliance Methods

a. BART for Nitrogen Oxides (NO X 

### )

i. Emission Limitations

1. NO X 

### emissions from EU040 shall not exceed 4.5 tons per day at all times when EU040 is operating, measured on a 30-day rolling average; and

2. NO X 

### emissions from EU042 shall not exceed 10.1 tons per day at all times when EU042 is operating, measured on a 30-day rolling average.

### -DRAFT3. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

4. The NO X 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s appro val of United’s BART determination.

ii. Compliance with the NO X 

### emission limit above will be demonstrated through the use of continuous emission monitoring syst ems (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

b. BART for Sulfur Dioxide (SO 2 

### )

i. Emission Limitations

1. SO 2 

### emissions from EU040 shall not exceed 106.3 tons over 30 days, measured as a 30-day rolling sum, at all times when EU040 is operating; and

2. SO 2 

### emissions from EU042 shall not exceed 197 tons over 30 days, measured as a 30-day rolling sum, at all times when EU 042 is operating.

3. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling sum

4. The SO 2 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s appro val of United’s BART determination.

ii. Compliance with the SO 2 

### emission limit above will be determined through the use of continuous emission monitoring system s (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissions from each line shall not exceed 0.01 gr/dscf.

ii. Compliance with the PM emission limits above will be determined using the compliance methods laid out in 40 CFR § 63 Subpart RRRRR, the taconite MACT, and determined based on the flow weighted mean concentration of all stacks for the furnace.

iii. Compliance with the PM emission limit must be demonstrated based on the timelines laid out in the taconite MACT.

### -DRAFTII. Recordkeeping and Reporting

a. Recordkeeping. United shall main tain electronic files of all information required by this Order in a form suitable for determination of United’s compliance with this Order by U.S. EPA or MPCA staff and readily available for U.S. EPA or MPCA in spection and review.

i. Permanent Records: United shall perman ently maintain the following information together with all amendments , revisions, and modifications to this information.

1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

ii. Non Permanent Records: United shall ma intain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facility requirements of United’s air emissions permit, pursuant to Minn. R. 7007.0800. Un ited shall retain the records for a minimum of five years following the date on which the record was generated. The most recent two years of info rmation must be kept on site

.

b. United shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

20. To conduct the following modeling analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling Protocol

a. By April 1, 2012, submit to the MPCA a mo deling protocol for the United facility for NO 2 

### emissions. The protocol must be submitted using MPCA’s most recent model protocol forms, AQDMP-01 and AQDMPS-01.

II. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### NAAQS and one-hour NO 2 

### NAAQS;

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

### -DRAFTGeneral.

21. This Order by Consent is not transferable or assignable to any person without the express written approval of the MPCA.

22. This Order by Consent is effective upon the date that it is signed by the MPCA Commissioner or his designee.

RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

IT IS SO ORDERED.

Minnesota Pollution Control Agency

______________________________________ Paul W. Aasen Commissioner

### -DRAFTSTATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER BY CONSENT United States Steel Corporation Keewatin Taconite, Inc.

The Minnesota Pollution Control Agency (MPCA) and United States Steel Corporation Keewatin Taconite, Inc. (Keetac) enter into this Administrative Order by Consent (Order) pursuant to Minn. Stat. § 116.07, subd. 9 (2010).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its mandatory Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants contributing to re gional haze are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

### -DRAFT5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided Keetac and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. United States Steel Corporation – Keewatin Taconi te, Inc. (Keetac) owns and operates a taconite mine and processing facility (“Facility”) in Keewatin , Minnesota. Keetac is authorized to operate two grate-kiln furnaces (EU030 and EU068/EU069/EU070 ). EU030 was constructed in 1976. The furnace is capable of processing 415 tons of pellets per hour with a heat input of 178.5 MMBtu/hr. Keetac was authorized to reconstruct and operate EU068/EU069/EU070 by a permit amendment that the MPCA issued on September 14, 2011. EU 068/EU069/EU070 are not yet operational.

8. The permit allows Keetac to combust natural gas, di stillate fuel oils, coal, and petroleum coke in the EU030 pelletizing furnace. Coal and natural gas are the primary fuels; coal is a significant source of sulfur. Another source of sulfur emissions from this furnace is the iron ore used to form the taconite green balls, although this represents a smaller cont ribution than the sulfur in the solid fuels burned. Sulfur dioxide emissions are currently controlled by wet scrubbers.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

9. The Rule includes 40 CFR 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

10. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. [40 CFR § 51.308(e)(ii)].

11. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

### -DRAFT12. The Keetac facility includes one unit (EU030) that is subject to BART. See RESULTS of Best Available Retrofit Technology (BART) Mo deling to Determine Sources Subject-to-BART in the State of Minnesota at http://proteus.pca.state.mn. us/publications/aq-sip2-07.pdf

.

13. Keetac’s EU030 Grate-Kiln pelletizing furnace was determined to be subject-to-BART, and US Steel performed a BART analysis for it. This unit has one associated stack vent, SV051.

14. MPCA determined and US Steel agreed that the Keetac Grate-Kiln pelletizing furnace (EU030) is subject-to-BART.

15. The MPCA determined that BART for this unit consists of

a. Operation of the existing wet scrubber to control SO 2 

### emissions; and

b. Good combustion practices, along with existing combustion controls and fuel blending to control NO X 

### emissions; and

c. Implementation of the taconite Maximum Achi evable Control Technology (MACT) standard to control PM emissions. [40 CFR 63, Subp. RRRRR].

16. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302 (c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish th e BART emission limit for Keetac.

LONG-TERM STRATEGY

17. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

18. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

19. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including Keetac, is their demonstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 50.17] and nitrogen dioxide (NO 2 

### ) [ 40 CFR § 50.11]. As a result, Keetac must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for Keetac will be completed.

ORDER

NOW, THEREFORE, IT IS ORDERED AND AGREED:

20. Keetac will install and operate any necessary control equipment or undertake any necessary work practices to meet the following requirem ents which represent BART for Keetac.

### -DRAFTI. BART Emission Limitation s and Compliance Methods

a. BART for Nitrogen Oxides (NO X 

### )

i. Emission Limitations

1. NO X 

### emissions from EU030 shall not exceed 12.35 tons per day at all times when EU030 is operating, measured on a 30-day rolling average.

2. Hours during which EU030 does not op erate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

3. The NO X 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s appro val of Keetac’s BART determination.

ii. Compliance with the NO X 

### emission limit above will be demonstrated through the use of continuous emission monitoring syst ems (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

b. BART for Sulfur Dioxide (SO 2 

### )

i. Emission Limitations

1. SO 2 

### emissions from EU030 shall not exceed 2.71 tons per day at all times when EU030 is operating, measured on a 30-day rolling average basis.

2. Hours during which EU030 does not op erate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

3. The SO 2 

### emission limit is effective on and after the date six months after the effective date of U.S. EPA’s appro val of Keetac’s BART determination.

ii. Compliance with the SO 2 

### emission limit above will be determined through the use of continuous emission monitoring system s (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissi ons from EU030 shall not exceed 0.01 gr/dscf.

ii. Compliance with the PM emission limits above will be determined using the compliance methods laid out in 40 CFR 63 Subpart RRRRR, the taconite MACT, and determined based on the flow weighted mean concentration of all stacks for the furnace.

### -DRAFTiii. Compliance with the PM emission limit must be demonstrated based on the timelines laid out in the taconite MACT.

II. Recordkeeping and Reporting

a. Recordkeeping. Keetac shall maintain electronic files of all information required by this Order in a form suitable for determination of Keetac’s compliance with this Order by U.S. EPA or MPCA staff and readily available for U.S. EPA or MPCA in spection and review.

i. Permanent Records: Keetac shall perman ently maintain the following information together with all amendments , revisions, and modifications to this information.

1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

ii. Non Permanent Records: Keetac shall ma intain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facility requirements of Keetac’s air emissions permit, pursuant to Minn. R. 7007.0800 and. Keetac shall retain the records for a minimum of five years following the date on which the record was generated. The most recent two years of info rmation must be kept on site

.

b. Keetac shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

21. To conduct the following modeling analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### NAAQS and one-hour NO 2 

### NAAQS;

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

### -DRAFTGeneral.

22. Nothing in this Order shall relieve Keetac of it s obligation to meet permitting requirements for any physical or operational change at its facility.

23. This Order by Consent supersedes and replaces the Administrative Order by Consent entered into by Keetac and the MPCA on September 27, 2007.

24. This Order by Consent is not transferable or assignable to any person without the express written approval of the MPCA.

25. This Order by Consent is effective upon the date that it is signed by the MPCA Commissioner or his designee.

26. The terms of this Order by Consent may be amended by the written agreement of the parties.

RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

IT IS SO ORDERED.

United States Steel Corporation, Keewatin Taconite, Inc. Minnesota Pollution Control Agency

______________________________________ ______________________________________ Michael S. Williams Senior Vice President - North America Flat Roll Operations United States Steel Corporation Paul W. Aasen Commissioner

### -DRAFTSTATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : ADMINISTRATIVE ORDER BY CONSENT United States Steel Corporation Minntac

The Minnesota Pollution Control Agency (MPCA) and United States Steel Corporation, Minntac (Minntac) enter into this Administrative Order (Order) pursuant to Minn. Stat . § 116.07, subd. 9 (2010).

FINDINGS OF FACT

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protecti on Agency (U.S. EPA) pu blished regulations to address visibility impairment in our nation’s larg est national parks and wilderness (“Class I”) areas [70 Fed. Reg. 39103]. This rule is commonly know n as the “Regional Haze Rule” [40 CFR §§ 51.300- 51.309]. The Regional Haze Rule (Rule) requires that Minnesota establish and achieve visibility goals for each of its mandatory Class I areas by 2018.

2. The Rule regulates the emission of pollutants th at contribute to regional haze. The MPCA has determined that the key pollutants contributing to re gional haze are particulate matter (PM), sulfur dioxide (SO 2 

### ), and nitrogen oxides (NO X 

### ).

3. The Rule requires that Minnesota submit a Regional Haze State Implementation Plan (SIP) to U.S. EPA for its approval. The SIP must include:

a. Reasonable Progress Goals – Minnesota must estab lish, for each Class I area within the state, “goals (expressed in deciviews) that provid e for reasonable progress towards achieving natural visibility conditions.” [40 CFR § 51.308(d)(1)].

b. Long-Term Strategy – Minnesota must submit a long-term strategy that addresses regional haze visibility impairment, and includes “measures as necessary to achieve the reasonable progress goals established by States having mandatory Class I Federal areas.” [40 CFR § 51.308(d)(3)].

c. Best Available Retrofit Technology – The Rule regulates certain stationary sources that could contribute to visibility impairment in Cla ss I areas. States, including Minnesota, must determine what constitutes the best available re trofit technology (BAR T) to control for PM, SO 2 

### , and NO X 

### and to establish emissions limits that are consistent with BART for these sources. The limits must be included in the SIP for U.S. EPA approval.

4. The MPCA submitted a Regional Haze SIP to U.S. EPA on December 30, 2009, which included the required Reasonable Progress Goals and Long-Term Strategy and identified the BART-eligible and subject-to-BART sources, listed the MPCA’s BART determinatio ns, and included associated BART emission limits where MPCA had sufficient emissions data to set such limits. On April 1, 2010, U.S. EPA notified the MPCA that the submittal was complete.

5. Subsequently, MPCA prepared a supplemental SIP submittal that revised the long-term strategy and included BART emission limits where additional data had been collected. The supplemental SIP submittal also included this Order and supporting documents.

### -DRAFT6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submit tal on public notice for 45 days. < CITATION .> The public comment period provided Minntac and members of the general public an opportunity to comment on this Order and the other elements of the proposed supplemental SIP, including the BART emission limits, prior to U.S. EPA’s final decision on the SIP.

THE FACILITY

7. United States Steel – Minntac (Minntac) owns and operates a taconite mine and processing facility (“Facility”) at County Highway 102, on the Mesabi Ra nge north of the City of Mountain Iron, St. Louis County, Minnesota.

8. Minntac operates five indurating furn aces (Lines 3, 4, 5, 6, and 7). Line 3 (Step I) began operation in 1967; Lines 4 and 5 (Step II) began operation in 1972; and Lines 6 and 7 (Step III) began operation in 1978.

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

9. The Rule includes 40 CFR 51, Appendix Y “ Guidelines for BART Determinations Under the Regional Haze Rule ” which provides direction for determining whic h sources may need to install BART and for determining BART.

10. To satisfy the Rule, the MPCA determined what constitutes BART for each BART-eligible unit and established emission limits consistent with its de termination of BART. As required, the MPCA took into consideration the technology available, the costs of complianc e, the energy and the non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the so urce, and the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. [40 CFR § 51.308(e)(ii)].

11. To identify the BART-eligible emission units, MPCA used the following criteria:

a. One, or more, emission(s) units at the facility fi t within one of the twenty-six (26) categories listed in the 40 CFR 51, Appendix Y Guidelines ;

b. The emission unit(s) were in existence on Augu st 7, 1977 and began operation at some point on or after August 7, 1962; and

c. The sum of the potential emissions from all emi ssion unit(s) identified in the previous two bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO 2 

### , NO X 

### , and PM.

### -DRAFT12. Minntac includes units that are subject to BART. See RESULTS of Best Available Retrofit Technology (BART) Modeling to Determine Sources Subj ect-to-BART in the State of Minnesota at http://proteus.pca.state.mn.us/publications/aq-sip2-07.pdf

.

13. Minntac has five units, the indurating furnaces identified as Emission Units 225, 261, 282, 315, and 334 in Air Emissions Permit No. 13700005-005, that are subject-to-BART and for which a BART analysis was performed. The stac k vent associated with EU225, th e Line 3 indurating furnace, is SV103. The stack vent associated with EU261, the Line 4 indurating furnace, is SV118. The stack vent associated with EU282, the Line 5 indurating furn ace, is SV127. The stack vent associated with EU315, the Line 6 indurating furnace, is SV144. Th e stack vent associated with EU334, the Line7 indurating furnace, is SV151.

14. MPCA determined and US Steel agreed that Mi nntac’s five indurating furnaces (EU225, EU261, EU282, EU315, and EU334) are subject-to-BART

15. The MPCA determined that BART for these units consists of:

a. Operation of the existing wet scrubber to control SO 2 

### emissions; and

b. Good combustion practices and fuel blending to control NO X 

### emissions for Lines 3, 4, 5, 6, and 7, with the addition of low-NO X 

### burners in the pre-heat zone for Lines 4, 5, 6, and 7; and

c. Implementation of the taconite Maximum Achi evable Control Technology (MACT) standard to control PM emissions. 40 CFR 63, Subp. RRRRR.

16. The MPCA must place BART emissi on limits in an enforceable do cument. [40 CFR § 51.302 (c)(3); 40 CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to i ssue this Administrative Order as the enforceable document by which to establish the BART emission limit for Minntac.

LONG-TERM STRATEGY

17. In the SIP, the MPCA established, as part of the lo ng-term strategy, a target or goal of a reduction in combined SO 2 

### and NO X 

### emissions from large point sources loca ted in St. Louis, Lake, Cook, Carlton, Itasca and Koochiching counties that emitted over 100 tons per year of either SO 2 

### or NO X 

### in 2002.

18. The MPCA also determined that the six taconite facilities in Minnesota may be undercontrolled, and that very few emission control technologies are known to be effective for the industrial processes involved in taconite production. The MPCA ther efore also established a requirement for these facilities to investigate control technologies and pollution prevention practices for their indurating furnaces as part of the long-term strategy.

19. The MPCA has determined that an appropriate mechanism for implementing the long-term strategy for the taconite facilities, including Minntac, is their demonstration that their facilities are in attainment with the one-hour National Ambient Air Quality Standards (NAAQS) for SO 2 

### [40 CFR § 50.17] and nitrogen dioxide (NO 2 

### ) [40 CFR § 50.11]. As a result, Minntac must model compliance with the one-hour and SO 2 

### and NO 2 

### NAAQS. This Order establishes the tasks and schedules by which the modeling for Minntac will be completed.

### -DRAFTORDER

NOW, THEREFORE, IT IS ORDERED AND AGREED:

20. Minntac will install and operate any necessary control equipment or undertake any necessary work practices to meet the following requirem ents, which represent BART for Minntac.

I. BART Emission Limitation s and Compliance Methods

a. BART for Nitrogen Oxides (NO X 

### )

i. Emission Limitations

1. NO X 

### emissions from Line 3, EU225, shall not exceed 7.85 tons per day at all times when EU225 is operating, measured on a 30-day rolling average;

2. NO X 

### emissions from Line 4, EU261, shall not exceed 9.85 tons per day at all times when EU261 is operating, measured on a 30-day rolling average;

3. NO X 

### emissions from Line 5, EU282, shall not exceed 9.46 tons per day at all times when EU282 is operating, measured on a 30-day rolling average;

4. NO X 

### emissions from Line 6, EU315, shall not exceed 7.14 tons per day at all times when EU315 is operating, measured on a 30-day rolling average;

5. NO X 

### emissions from Line 7, EU334, shall not exceed 5.51 tons per day at all times when EU334 is operating, measured on a 30-day rolling average.

6. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

7. These NO X 

### emission limits are effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. Compliance with the NO X 

### emission limits above will be demonstrated through the use of continuous emission monitoring syst ems (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

b. BART for Sulfur Dioxide (SO 2 

### )

i. Emission Limitations

1. SO 2 

### emissions from Line 3, EU225, shall not exceed 1.28 tons per day at all times when EU225 is operating, measured on a 30-day rolling average. This limit applies only when the line is burning natural gas or wood;

### -DRAFT2. SO 2 

### emissions from Line 4, EU261, shall not exceed 1.10 tons per day at all times when EU261 is operating, measured on a 30-day rolling average. This limit applies only when the line is burning natural gas or wood;

3. SO 2 

### emissions from Line 5, EU282, shall not exceed 1.19 tons per day at all times when EU282 is operating, measured on a 30-day rolling average. This limit applies only when the line is burning natural gas or wood;

4. SO 2 

### emissions from Line 6, EU315, shall not exceed 1.47 tons per day at all times when EU315 is operating, measured on a 30-day rolling average;

5. SO 2 

### emissions from Line 7, EU334, shall not exceed 1.61 tons per day at all times when EU334 is operating, measured on a 30-day rolling average.

6. Hours during which the subject emission unit does not operate are not included in the calculation of the rolling average. Periods of startup, shutdown and malfunction are included in the calculation of the rolling average.

7. These SO 2 

### emission limits are effective on and after the date six months after the effective date of U.S. EPA’s approval of this BART determination.

ii. Compliance with the SO 2 

### emission limits above will be determined through the use of continuous emission monitoring system s (CEMS) in accordance with Minn. R. 7017.1002 through Minn. R. 7017.1220.

c. BART for Particulate Matter (PM)

i. Emission Limitations

1. Filterable (front-half) PM emissions from each line shall not exceed 0.01 gr/dscf

ii. Compliance with the PM emission limits above will be determined using the compliance methods laid out in 40 CFR 63 Subpart RRRRR, the taconite MACT, and determined based on the flow weighted mean concentration of all stacks for each furnace.

iii. Compliance with the PM emission limit must be demonstrated based on the timelines laid out in the taconite MACT.

II. Recordkeeping and Reporting

a. Recordkeeping. Minntac shall maintain electronic files of all information required by this Order in a form suitable for determination of Minntac’s compliance with this Order by U.S. EPA or MPCA staff and readily available for U.S. EPA or MPCA in spection and review.

i. Permanent Records: Minntac shall permanen tly maintain the following information together with all amendments , revisions, and modifications to this information.

### -DRAFT1. Information on NO X 

### , SO 2 

### , and PM emission limits and operational requirements imposed by this Order. These records include this Order.

ii. Non Permanent Records: Minntac shall maintain monitoring, testing, startup, shutdown, bypass, breakdowns, excess emissions and noncompliance with operational requirements records pertaining to the requirements of this Order in the manner required in the total Facility requirements of Minntac’s air emissions permit, pursuant to Minn. R. 7007.0800 and. Minntac shall retain the records for a minimum of five years following the date on which the record was generated. The most recent two years of info rmation must be kept on site

.

b. Minntac shall, in the Semiannual Deviations Report required under Minn. R. 7007.0800, Subp. 6(A)(2), report each instance in which an emission limit was not met. This includes periods of startup, shutdown, and malfunction.

21. To conduct the following modeling analyses and submit the following information in order to ensure expeditious attainment of the one-hour SO 2 

### and NO 2 

### NAAQS as part of the long-term strategy

I. Modeling and Emission Limits Demonstrating Compliance

a. By December 15, 2012, submit to the MPCA:

i. A modeling demonstration that shows mo deled compliance with the one-hour SO 2 

### NAAQS and one-hour NO 2 

### NAAQS;

ii. A table of proposed emission limits from the facility, by emission unit and stack vent, that result in modeled compliance with the one-hour SO 2 

### and NO 2 

### NAAQS;

iii. A description of the work practices or cont rols to be implemented in order to meet the proposed emission limits; and

iv. A detailed schedule for implementation of the necessary work practices or controls which ensures that they will be in place and the emission limits achieved by June 30, 2017.

General.

22. Nothing in this Order shall relieve Minntac of its obligation to meet permitting requirements for any physical or operational change at its facility.

23. This Order by Consent supersedes and replaces the Administrative Order by Consent entered into by Minntac and the MP CA on September 27, 2007.

24. This Order by Consent is not transferable or assignable to any person without the express written approval of the MPCA.

25. This Order by Consent is effective upon the date that it is signed by the MPCA Commissioner or his designee.

### -DRAFT26. The terms of this Order by Consent may be amended by the written agreement of the parties.

RESERVATION OF AUTHORITY Nothing in this Order shall prevent the MPCA from taking action to enforce the requirements of this Order, or from requiring additional action by the Regulated Party if necessary to ensure compliance with the Regional Haze rule and other MPCA rules and statutes.

United States Steel Corporation, Minntac Minnesota Pollution Control Agency

______________________________________ ______________________________________ Michael S. Williams Senior Vice President - North America Flat Roll Operations United States Steel Corporation Paul W. Aasen Commissioner

### Appendix 3: Termination of Monitoring Orders

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : AMENDMENT NO. 1 TO ADMINISTRATIVE ArcelorMittal – Minorca Mine Inc. ORDER BY CONSENT

I. RECITALS

A. PARTIES. This Amendment Number 1 applies to and is binding upon the following parties:

1. ArcelorMittal - Minorca Mi ne, Inc. (“Regulated Party”)

2. The Minnesota Pollution control Agency (“MPCA”)

Unless specified otherwise in this amendment Nol. 1, where this Amendment No. 1 identifies actions to

be taken by the MPCA, the Commissioner or the Co mmissioner’s designees shall act on the MPCA’s

behalf.

B. ADMINISTRATIVE ORDER BY CONSENT. The MPCA and the Regulated Party have entered into

an Administrative Order by Consent (“Order”) rega rding the Regulated Party’s facility located near

Virginia, Minnesota. The effective date of the Order was January 22, 2009.

C. STATEMENT OF THE FACTS. The following constitutes a summary of the facts upon which this

Amendment No. 1 is based:

1. By its terms, the Order was to remain in effect until BART-related terms and conditions

of the Order became enforceable parts of the Regulated Party’s air emissions permit.

2. The terms and conditions of the Order have been satisfied so it is not necessary to

include Bart-related terms and conditions of the Orde r in the Regulated party’s air emissions permit, nor

is it necessary to continue the Order in effect.

II. AGREEMENT AMENDMENT

NOW THEREFORE, pursuant to paragraph 16 of the Order, the MPCA and Regulated Party hereby agree

to amend the Order to terminate it effective upon th e date of the signature of the Commissioner of the

MPCA or the Commissioner’s representative below.

### BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE AUTHORITY TO AMEND THE ORIGINAL AGRE MENT AND THAT THEY AGREE WITH THIS AMENDMENT AS WRITTEN

ARCELORMITTAL - STATE OF MINNESOTA MINORCA MINE INC. POLLUTION CONTROL AGENCY

__________________________________ _________________________________ Jonathon Holmes Jeff J. Smith Vice President/Operations Manager Division Director ArcelorMittal Minorca Mine Inc Industrial Division

Dated: ____________________________ Dated: ___________________________1 

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : AMENDMENT NO. 1 TO ADMINISTRATIVE Hibbing Taconite Company ORDER BY CONSENT

I. RECITALS

A. PARTIES. This Amendment Number 1 applies to and is binding upon the following parties:

1. Hibbing Taconite Company (“Regulated Party”)

2. The Minnesota Pollution control Agency (“MPCA”)

Unless specified otherwise in this amendment Nol. 1, where this Amendment No. 1 identifies actions to

be taken by the MPCA, the Commissioner or the Co mmissioner’s designees shall act on the MPCA’s

behalf.

B. ADMINISTRATIVE ORDER BY CONSENT. The MPCA and the Regulated Party have entered into

an Administrative Order by Consent (“Order”) regardi ng the Regulated Party’s facility located in Hibbing,

Minnesota. The effective date of the Order was March 3, 2008.

C. STATEMENT OF THE FACTS. The following constitutes a summary of the facts upon which this

Amendment No. 1 is based:

1. By its terms, the Order was to remain in effect until BART-related terms and conditions

of the Order became enforceable parts of the Regulated Party’s air emissions permit.

2. The terms and conditions of the Order have been satisfied so it is not necessary to

include BART-related terms and conditions of the Order in the Regulated party’s air emissions permit,

nor is it necessary to continue the Order in effect.

II. AGREEMENT AMENDMENT

NOW THEREFORE, pursuant to paragraph 16 of the Order, the MPCA and Regulated Party hereby agree

to amend the Order to terminate it effective upon th e date of the signature of the Commissioner of the

MPCA or the Commissioner’s representative below.

### BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE AUTHORITY TO AMEND THE ORIGINAL AGRE MENT AND THAT THEY AGREE WITH THIS AMENDMENT AS WRITTEN

HIBBING TACONITE COMPANY STATE OF MINNESOTA POLLUTION CONTROL AGENCY

__________________________________ _________________________________ Edward M. LaTendresse Jeff J. Smith General Manager Division Director Hibbing Taconite Company Industrial Division

Dated: ____________________________ Dated: ___________________________

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : AMENDMENT NO. 1 TO ADMINISTRATIVE Northshore Mining Company – Silv er Bay ORDER BY CONSENT

I. RECITALS

A. PARTIES. This Amendment Number 1 applies to and is binding upon the following parties:

1. Northshore Mining Company – Silver Bay (“Regulated Party”)

2. The Minnesota Pollution control Agency (“MPCA”)

Unless specified otherwise in this amendment Nol. 1, where this Amendment No. 1 identifies actions to

be taken by the MPCA, the Commissioner or the Co mmissioner’s designees shall act on the MPCA’s

behalf.

B. ADMINISTRATIVE ORDER BY CONSENT. The MPCA and the Regulated Party have entered into

an Administrative Order by Consent (“Order”) regard ing the Regulated Party’s facility located in Silver

Bay, Minnesota. The effective date of the Order was April 7, 2008.

C. STATEMENT OF THE FACTS. The following constitutes a summary of the facts upon which this

Amendment No. 1 is based:

1. By its terms, the Order was to remain in effect until BART-related terms and conditions

of the Order became enforceable parts of the Regulated Party’s air emissions permit.

2. The terms and conditions of the Order have been satisfied so it is not necessary to

include Bart-related terms and conditions of the Orde r in the Regulated party’s air emissions permit, nor

is it necessary to continue the Order in effect.

II. AGREEMENT AMENDMENT

NOW THEREFORE, pursuant to paragraph 16 of the Order, the MPCA and Regulated Party hereby agree

to amend the Order to terminate it effective upon th e date of the signature of the Commissioner of the

MPCA or the Commissioner’s representative below.

### BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE AUTHORITY TO AMEND THE ORIGINAL AGRE MENT AND THAT THEY AGREE WITH THIS AMENDMENT AS WRITTEN

NORTHSHORE MINING COMPANY - STATE OF MINNESOTA SILVER BAY POLLUTION CONTROL AGENCY

__________________________________ _________________________________ Mike Mlinar Jeff J. Smith Vice President/General Manager Division Director Northshore Mining Company Industrial Division

Dated: ____________________________ Dated: ___________________________

### STATE OF MINNESOTA Minnesota Pollution Control Agency

In the Matter of : AMENDMENT NO. 1 TO AMENDED United Taconite, LLC ADMINISTRATIVE ORDER BY CONSENT

I. RECITALS

A. PARTIES. This Amendment Number 1 applies to and is binding upon the following parties:

1. United Taconite, LLC. (“Regulated Party”)

2. The Minnesota Pollution control Agency (“MPCA”)

Unless specified otherwise in this amendment Nol. 1, where this Amendment No. 1 identifies actions to

be taken by the MPCA, the Commissioner or the Co mmissioner’s designees shall act on the MPCA’s

behalf.

B. ADMINISTRATIVE ORDER BY CONSENT. The MPCA and the Regulated Party have entered into

an Administrative Order by Consent (“Order”) rega rding the Regulated Party’s facility located near

Forbes, Minnesota. The effective date of the Order was May 18, 2009.

C. STATEMENT OF THE FACTS. The following constitutes a summary of the facts upon which this

Amendment No. 1 is based:

1. By its terms, the Order was to remain in effect until BART-related terms and conditions

of the Order became enforceable parts of the Regulated Party’s air emissions permit.

2. The terms and conditions of the Order have been satisfied so it is not necessary to

include BART-related terms and conditions of the Order in the Regulated party’s air emissions permit,

nor is it necessary to continue the Order in effect.

II. AGREEMENT AMENDMENT

NOW THEREFORE, pursuant to paragraph 20 of the Order, the MPCA and Regulated Party hereby agree

to amend the Order to terminate it effective upon th e date of the signature of the Commissioner of the

MPCA or the Commissioner’s representative below.

### BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE AUTHORITY TO AMEND THE ORIGINAL AGRE MENT AND THAT THEY AGREE WITH THIS AMENDMENT AS WRITTEN

ARCELORMITTAL - STATE OF MINNESOTA MINORCA MINE INC. POLLUTION CONTROL AGENCY

__________________________________ _________________________________ John Tuomi Jeff J. Smith General Manager Division Director United Taconite, LLC Industrial Division

Dated: ____________________________ Dated: ___________________________