1 

Regional Haze

State Implementation 

Plan Supplement

<March> 2012

Draft December 2011
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 Minnesota Pollution Control Agency (MPCA) 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 contained Best Available Retrofit Technology (BART) determinations for 

several electric generating units (EGUs) 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 enforceable. On December 20, 2010, 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 enforceable 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 Plan, 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. These 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 makes 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 determined 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 determination. One of the reasons that the MPCA felt 

comfortable making this determination is that many emission reductions were already occurring in 

preparation for CAIR. 

Draft December 2011
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, the 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 Pollution Rule, also known as the Transport Rule (TR), 

as described in 40 CFR § 52.1240 and 40 CFR § 52.1241. 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 NOX budget of 31,443 from 2009 through 

2014, and 26,203 in 2015 and later. Under TR, Minnesota’s annual NOX budget is 28,977. CAIR also 

proposed to use Title IV acid rain allowances, on a 2:1 basis, to reduce SO2 emissions. Minnesota’s Title 

IV allocation is 97,181, so the annual SO2 budget under CAIR would have been 48,950 tons per year. 

Minnesota’s SO2 allocation under TR is 41,139 tons per year. 

Because the TR is as stringent as CAIR, it is reasonable 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 made in the initial SIP submittal, Minnesota’s subjectto-BART power plants simply need to comply with their 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 technology 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 determined that, generally, BART for the taconite 

facilities consisted of operation of existing scrubbers to control sulfur dioxide (SO2) emissions, good 

combustion practices to control nitrogen oxides (NOX) emissions, and continued implementation of the 

taconite Maximum Achievable Control Technology (MACT) standard for control 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 NOX at all cases and for SO2 in the 

case of facilities that burn higher sulfur fuels. The MPCA entered into Administrative Orders with the 

facilities, which required the facilities to do increased monitoring of their emissions and report 

emissions to the MPCA. 

Draft December 2011
4 

The MPCA felt that at least one year of emissions data was needed from each 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 lists the subject-to-BART unit(s) at each facility, the 

BART determination for SO2 and NOX, 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, are included as Appendix 1. Administrative Orders 

making the BART limits for all three pollutants enforceable are included in Appendix 2. 

The MPCA is requesting that EPA approve the attached Administrative Orders in Appendix 2, which 

contain BART emission limits and compliance methods, 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 concentrator 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 after 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) submit 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 amendment. The MPCA notified United Taconite of the BART 

limits on September 22, 2011. 

On December 8, 2011, United Taconite proposed that the NOX and SO2 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 limits provided greater annual reductions of NOX and 

SO2 than would be provided by the MPCA’s initial BART 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 

NOX emissions at the facility.

Draft December 2011
Table 1: Taconite BART Determinations and Emission Limits for NOX and SO2

Facility Unit Stack Vent NOX BART NOX BART 

Limit 

SO2 BART 

Arcelor Mittal Indurating 

Furnace 

EU026 SV014, 

SV015, SV016, 

SV017 

Good combustion practices, low NOX

burners in the pre-heat zone, furnace energy efficiency project (2007) 

1018.0 lbs/hr Existing we

scrubber 

Hibbing Taconite 

Line 1 Pelletizing Furnace 

EU020 SV021, 

SV022, 

 SV023, 

SV024 

Good combustion practices, furnace energy efficiency projects (2005 and 2006) 

447.4 lbs/hr Existing we

scrubber 

Line 2 Pelletizing Furnace 

EU021 SV025, 

SV026, 

 SV027, 

SV028 

Good combustion practices, furnace energy efficiency projects (2005 and 2006) 

571.7 lbs/hr Existing we

scrubber 

Line 3 Pelletizing Furnace 

EU022 SV029, 

SV030, 

 SV031, 

SV032 

Good combustion practices, furnace energy efficiency projects (2005 and 2006) 

338.3 lbs/hr Existing we

scrubber 

Northshore Mining 

Indurating Furnace 11 

EU100, 

EU104 

SV101, SV102, SV103, SV104, 

SV105 

Good combustion practices 115.5 lbs/hr Existing we

scrubber 

 Indurating 

Furnace 12 

EU110, 

EU114 

SV111, SV112, SV113, SV114, 

SV115 

Good combustion practices 115.5 lbs/hr Existing we

scrubber 

 Process Boiler #1 EU003 SV003 Existing controls 0.17 lbs/

MMBtu 

N/A 

 Process Boiler #2 EU004 SV003 Existing controls 0.17 lbs/

MMBtu 

N/A 

United Taconite Line 1 Pellet 

Induration 

EU040 SV046 Good combustion practices, past 

heat recuperation project 

4.5 tons per day 

Existing wescrubber 

Line 2 Pellet Induration 

EU042 SV048, 

SV049 

Good combustion practices 10.1 tons per 

day 

Existing wescrubber, Fblending 

Draft 
Facility Unit Stack Vent NOX BART NOX BART 

Limit 

SO2 BART 

U.S. Steel - Keetac 

Phase II Grate-Kiln Pelletizing Furnace 

EU030 SV051 Existing combustion controls and 

fuel blending 

12.35 tons per day 

Existing wescrubber 

U.S. Steel –

Minntac 

Line 3 Indurating Furnace 

EU225 SV103 Good combustion practices, fuel 

blending 

7.85 tons per day 

Existing con

Line 4 Indurating Furnace 

EU261 SV118 Good combustion practices, fuel 

blending, low-NOX burners in the 

preheat zone 

9.85 tons per day 

Existing con

Line 5 Indurating Furnace 

EU282 SV127 Good combustion practices, fuel 

blending, low-NOX burners in the 

preheat zone 

9.46 tons per day 

Existing con

Line 6 Indurating Furnace 

EU315 SV144 Good combustion practices, fuel 

blending, low-NOX burners in the 

preheat zone 

7.14 tons per day 

Existing con

Line 7 Indurating Furnace 

EU334 SV151 Good combustion practices, fuel 

blending, low-NOX burners in the 

preheat zone 

5.51 tons per day 

Existing con

Draft 
7 

Long Term Strategy: Northeast Minnesota Plan

The December 2009 SIP submittal includes, as part of the long term strategy, the Northeast Minnesota 

Plan to reduce emissions of SO2 and NOX 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 components. The first is a goal of a 30% reduction in 

combined SO2 and NOX 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 emission inventory data is available, emissions were 

down by 39%. Based on projections at the beginning of 2011, it appears Minnesota will meet both the 

20% by 2012 and 30% by 2018 goals. 

The second part of the Northeast Minnesota Plan laid out a strategy for 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 likely to be undercontrolled. Very few emission control 

technologies have been demonstrated on the indurating 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 prevention practices through pilot testing, and report to 

MPCA on the feasibility and cost effectiveness of the controls. Any reasonable controls would then be 

installed. This was intended to evolve the controls available for these facilities, 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 would then report to the MPCA on the results in 

early 2013, and the MPCA would review those reports. Any control measures that were determined to 

be reasonable using the five factors 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 SO2 and NO2, which appear able to drive more stringent controls and on a faster 

timeline than envisioned by the pilot testing. Therefore, 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 evolution of control technologies 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 NO2, and SO2 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 

Draft December 2011
8 

conducted for NOX and SO2 emissions.1 The Order then goes on to require that each facility provide, by 

the end of 2012, the following information: 

• Modeling that demonstrates compliance 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 for the pilot testing strategy laid out in the original 

SIP submittal. The requirements to demonstrate attainment with the NAAQS for NOX and SO2 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 reductions 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. 

Draft December 2011
Appendix 1: BART Determination Memos 

 

Draft December 2011
DEPARTMENT: 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 Environmental 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 NOX 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 Minorca Mine Inc. 

5950 Old Highway 53 North 

Virginia, MN, St. Louis County 

Contact: Ms. Jaime Baggenstoss, 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 taconite ore mining, crushing, grinding, concentrating, 

agglomerating, and indurating. The larger sources of air emissions 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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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. 

Draft December 2011
The MPCA is required to determine BART for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions 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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 NOX BART limit consistent with that determination is: 

Emission Unit Name EU Number1

 Control Equipment & Stack Numbers2

Indurating Furnace EU026 SV014, SV015, SV016, SV017 

 2.3 The BART Determination

The MPCA’s NOX 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 NOX 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 Administrative Order, under which Arcelor provided additional NOX

emission information to the MPCA. 

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NOX emission information provided by Arcelor. The MPCA focused analysis on a set of 157 

hourly NOX emission data points collected in March 2008. Under the previously mentioned Administrative Order, Arcelor 

was required to collect “a minimum of 150 one-hour data points under the range of [furnace] operating parameters that 

influence NOX 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 hour. 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 met 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 NOX emissions. 

Draft December 2011
The example calculation below shows the 99% upper prediction level: 

 Mean of 30 data points ൌ Χത ൅ ሾ2.608 ൈ ߪ ൈ ඨሺ

1

30 ൅

1

157ሻሿ

• Where Χത and σ are, respectively, the mean and standard deviation of the sample of 157 hourly-averaged 

NOX 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 

• ටሺ 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 NOX 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 alleviate concerns that any one stack test, even an extended 

stack test, cannot capture all 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 157 data points as a representative population, from which 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 overall “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 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. In the bootstrapping technique, the standard error of a 30 point data set built from the new surrogate 

population (built from the mean of each of 2000 randomly selected 30 data point sample sets) ranged from 5.670 to 

9.269. 

The MPCA then looked at this highest standard error, and used that standard error (se) and the mean of the original 157 

data point sample to develop an additional 99% UPL. Because 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: Χത ൅ ሾ2.576 ൈ ݏ݁ሿ. For the data from Arcelor, this is: 994.1 ൅ ሾ2.576 ൈ 9.269ሿ, which results in a value 

of 1018.0. 

The MPCA also looked at emissions information from three-hour compliance stack tests conducted from 2000 through 

2009. These data further support the BART limit, as all would have demonstrated compliance with the limit established. 

Draft December 2011
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 ArcelorMittal, the MPCA has determined that an appropriate BART NOX limit 

is 1018.0 lbs/hour. This limit is for all four stacks from the indurating furnace combined, and is a 30-day rolling average. 

Compliance is to be determined through NOX performance testing, simultaneously measured for 30 hourly data points. 

The MPCA is requiring this longer stack testing in order to ensure that the sample is sufficiently representative and long 

enough to capture periods of both higher and lower emissions, in order to ensure compliance. 

Draft December 2011
Arcelor Mittal Mining - Data for NOX BART Limit on Indurating Furnaces

ID Timestamp

NOx lbs/hour 

(Arcelor)

NOx lbs/hour 

(MPCA)

1 3/12/08 0:30 1037.5 1037.4 Descriptive Statistics

2 3/12/08 1:30 1013.4 1013.2 Arcelor Data MPCA Data

3 3/12/08 2:30 1013.9 1013.7 Average 994.1 980.3

4 3/12/08 3:30 1026.6 1026.5 St Dev 31.2 50.6

5 3/12/08 4:30 1043.1 1042.9 Max 1060.5 1060.4

6 3/12/08 5:30 1048.8 1048.7 Min 909.4 732.1

7 3/12/08 6:30 1033.1 1033.0 t0.05, c-1 1.975 1.975

8 3/12/08 7:30 1006.5 1006.4 UPL 95% 1006.405 1000.193

9 3/12/08 8:30 976.7 976.6 t0.01, c-1 2.608 2.608

10 3/12/08 9:30 973.9 973.8 UPL 99% 1010.340 1006.574

11 3/12/08 10:30 1043.0 1042.9

12 3/12/08 11:30 1027.1 1026.9

13 3/12/08 12:30 1001.3 912.5

14 3/12/08 13:30 1001.1 838.9 Test Date and Time Stack and Run NOX Emission Rate, lbs/hr

15 3/12/08 14:30 983.7 983.5 June 2000 Furnace Average 853.0

16 3/12/08 15:30 959.0 958.8 Stack A

17 3/12/08 16:30 953.0 952.8 06/27/01 0830-1015 Run 1 144.5

18 3/12/08 17:30 956.8 894.0 06/27/01 1105-1213 Run 2 145.3

19 3/13/08 0:30 991.4 991.2 06/27/01 1305-1412 Run 3 154.8

20 3/13/08 1:30 1019.4 1019.3 Stack B

21 3/13/08 2:30 1021.6 1021.4 06/27/01 0830-1015 Run 1 176.7

22 3/13/08 3:30 1006.8 1006.7 06/27/01 1105-1213 Run 2 213.8

23 3/13/08 4:30 986.7 986.6 06/27/01 1305-1412 Run 3 181.8

24 3/13/08 5:30 977.1 977.0 Stack C

25 3/13/08 6:30 926.2 926.1 06/27/01 0830-1015 Run 1 218.3

26 3/13/08 7:30 983.5 983.4 06/27/01 1105-1213 Run 2 218.5

27 3/13/08 8:30 998.7 998.6 06/27/01 1305-1412 Run 3 222.7

28 3/13/08 9:30 993.3 993.2 Stack D

29 3/13/08 10:30 964.6 964.5 06/27/01 0830-1015 Run 1 301.1

30 3/13/08 11:30 976.3 732.1 06/27/01 1105-1213 Run 2 283.4

31 3/13/08 12:30 995.2 995.0 06/27/01 1305-1412 Run 3 297.8

32 3/13/08 13:30 976.4 976.2

33 3/13/08 14:30 990.0 989.9 February 2001 Furnace Average 537.0

34 3/13/08 15:30 961.8 961.7 Stack A

35 3/13/08 16:30 975.5 975.3 02/15/01 0915-1015 Run 1 42.9

36 3/13/08 17:30 1032.5 1032.4 02/15/01 1030-1130 Run 2 33.0

37 3/13/08 18:30 1040.2 1036.8 02/15/01 1145-1245 Run 3 32.9

38 3/13/08 19:30 1040.2 1002.2 Stack B

39 3/13/08 20:30 1015.9 1012.4 02/15/01 0915-1015 Run 1 94.7

40 3/13/08 21:30 1007.4 1007.3 02/15/01 1030-1130 Run 2 60.6

41 3/13/08 22:30 1022.7 1022.5 02/15/01 1145-1245 Run 3 61.9

42 3/13/08 23:30 1060.5 1060.4 Stack C

43 3/14/08 0:30 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 1002.5 1002.4 02/15/01 1030-1130 Run 2 206.8

45 3/14/08 2:30 1004.2 1004.1 02/15/01 1145-1245 Run 3 170.8

46 3/14/08 3:30 993.7 993.5 Stack D

47 3/14/08 4:30 975.4 975.3 02/15/01 0915-1015 Run 1 215.2

48 3/14/08 5:30 987.7 987.6 02/15/01 1030-1130 Run 2 244.9

49 3/14/08 6:30 1011.2 1011.0 02/15/01 1145-1245 Run 3 256.4

50 3/14/08 7:30 1035.7 948.1

51 3/14/08 8:30 1000.7 835.4 January 2002 Furnace Average 821

52 3/14/08 9:30 988.7 899.5 Stack A

53 3/14/08 10:30 935.2 935.0 1/23/2002 1040 - 1139 Run 1 109.1

54 3/14/08 11:30 977.9 977.8 1/23/2002 1147 - 1246 Run 2 110.0

55 3/14/08 18:45 958.1 958.0 1/23/2002 1255 - 1354 Run 3 116.2

56 3/14/08 19:45 976.3 976.2 Stack B

57 3/17/08 14:45 915.1 915.0 1/23/2002 0710 - 0809 Run 1 150.9

58 3/17/08 15:45 975.2 975.1 1/23/2002 0819 - 1918 Run 2 148.4

59 3/17/08 16:45 1042.3 1042.1 1/23/2002 0927 - 1026 Run 3 146.5

60 3/17/08 17:45 1037.9 1037.8 Stack C

61 3/17/08 18:45 1035.4 1035.3 1/22/2002 1320 - 1419 Run 1 224.9

62 3/17/08 19:45 1045.2 1045.1 1/22/2002 1428 - 1527 Run 2 222.3

63 3/17/08 20:45 986.7 960.4 1/22/2002 1534 - 1633 Run 3 233.1

64 3/18/08 10:45 1009.4 1053.9 Stack D

65 3/18/08 11:45 1043.1 1043.0 1/22/2002 0900 - 0959 Run 1 323.2

66 3/18/08 12:45 1028.2 1023.5 1/22/2002 1017 - 1116 Run 2 330.6

67 3/18/08 13:45 1054.0 1053.8 1/22/2002 1138 - 1237 Run 3 348.5

68 3/18/08 14:45 1037.8 1037.7

69 3/18/08 15:45 1001.1 1000.9 June 2003 Furnace Average 726

70 3/18/08 16:45 1004.9 1004.7 Stack A

71 3/18/08 17:45 1018.7 1018.5 6/24/2003 0810 - 0910 Run 1 110.2

72 3/18/08 18:45 913.4 832.0 6/24/2003 1330 - 1430 Run 2 116.7

73 3/18/08 19:45 909.4 909.3 6/24/2003 1450 - 1550 Run 3 112.1

74 3/18/08 20:45 950.5 950.4 Stack B

75 3/18/08 21:45 980.2 980.1 6/24/2003 0810 - 0910 Run 1 137.5

76 3/18/08 22:45 1007.8 1007.7 6/24/2003 1330 - 1430 Run 2 127.1

77 3/18/08 23:45 995.0 994.8 6/24/2003 1450 - 1550 Run 3 126.5

78 3/19/08 0:45 985.4 985.3 Stack C

79 3/19/08 1:45 1010.5 1010.4 6/24/2003 0810 - 0910 Run 1 189.8

80 3/19/08 2:45 1051.2 1051.1 6/24/2003 1330 - 1430 Run 2 190.8

81 3/19/08 3:45 1027.5 1027.3 6/24/2003 1450 - 1550 Run 3 199.1

82 3/19/08 4:45 1040.6 1040.5 Stack D

83 3/19/08 5:45 1006.7 1006.6 6/24/2003 0810 - 0910 Run 1 294.0

84 3/19/08 6:45 992.0 991.8 6/24/2003 1330 - 1430 Run 2 284.2

Draft December 2011
85 3/19/08 7:45 1019.0 863.8 6/24/2003 1450 - 1550 Run 3 289.6

86 3/19/08 8:45 998.2 900.7

87 3/19/08 9:45 974.2 942.1 June 2005 Furnace Average 756

88 3/19/08 10:45 980.4 980.2 Stack A

89 3/19/08 11:45 969.8 969.7 6/28/2005 0810 - 0910 Run 1 113.4

90 3/19/08 12:45 1026.0 1025.8 6/28/2005 0935 - 1035 Run 2 104.2

91 3/19/08 13:45 1020.9 1020.7 6/28/2008 1045 - 1145 Run 3 106.2

92 3/19/08 14:45 1014.8 1014.6 Stack B

93 3/19/08 15:45 1000.1 999.9 6/28/2005 1210 - 1310 Run 1 137.7

94 3/19/08 16:45 981.9 978.7 6/28/2005 1325 - 1425 Run 2 140.2

95 3/19/08 17:45 982.1 982.0 6/28/2005 1440 - 1540 Run 3 138.8

96 3/19/08 18:45 990.7 990.6 Stack C

97 3/19/08 19:45 1001.9 1001.8 6/29/2005 0750 - 0850 Run 1 221.5

98 3/19/08 20:45 995.1 995.0 6/29/2005 0905 -1005 Run 2 215.8

99 3/19/08 21:45 952.6 952.4 6/29/2005 1020 - 1120 Run 3 207.2

100 3/19/08 22:45 933.8 933.6 Stack D

101 3/19/08 23:45 932.2 898.5 6/29/2005 1140 - 1240 Run 1 293.6

102 3/20/08 0:45 997.8 997.6 6/29/2005 1255 - 1355 Run 2 303.3

103 3/20/08 1:45 1023.9 1023.8 6/29/2005 1410 - 1510 Run 3 301.1

104 3/20/08 2:45 1016.2 1016.0

105 3/20/08 3:45 987.4 987.2 June 2007 Furnace Average 762

106 3/20/08 4:45 978.6 978.5 Stack A

107 3/20/08 5:45 978.6 978.5 6/19/2007 0955 - 1104 Run 1 102.5

108 3/20/08 6:45 1021.6 1021.5 6/19/2007 1140 - 1253 Run 2 100.1

109 3/20/08 7:45 1017.0 861.4 6/19/2007 1322 - 1428 Run 3 100.7

110 3/20/08 8:45 1020.3 921.4 Stack B

111 3/20/08 9:45 1028.6 1028.5 6/19/2007 1504 - 1609 Run 1 127.5

112 3/20/08 10:45 995.8 995.6 6/19/2007 1635 - 1739 Run 2 131.7

113 3/20/08 11:45 976.2 976.0 6/19/2007 1800 - 1904 Run 3 130.8

114 3/20/08 12:45 1020.3 1020.2 Stack C

115 3/20/08 13:45 1031.6 1007.0 6/20/2007 0610 - 0715 Run 1 199.9

116 3/20/08 14:45 980.6 912.9 6/20/2007 0740 - 0845 Run 2 210.4

117 3/20/08 15:45 936.5 936.4 6/20/2007 0914 - 1014 Run 3 231.4

118 3/20/08 16:45 933.9 933.8 6/20/2007 1051 - 1154 Run 4 201.5

119 3/20/08 17:45 913.4 871.7 Stack D

120 3/20/08 18:45 931.0 903.9 6/20/2007 1305 - 1412 Run 1 268.4

121 3/20/08 19:45 963.8 936.5 6/20/2007 1444 - 1547 Run 2 270.4

122 3/20/08 20:45 983.9 983.8 6/20/2007 1612 - 1717 Run 3 276.9

123 3/20/08 21:45 966.2 966.1

124 3/20/08 22:45 978.1 978.0 March/April 2009 Furnace Average 812

125 3/20/08 23:45 973.7 973.5 Stack A

126 3/21/08 0:45 976.0 975.8 3/31/2009 1015 Run 1 139.0

127 3/21/08 1:45 994.3 994.2 3/31/2009 1249 Run 2 148.0

128 3/21/08 2:45 1006.7 1006.5 4/1/2009 1248 Run 3 135.2

129 3/21/08 3:45 969.3 969.2 Stack B

130 3/21/08 4:45 1011.6 1011.4 4/1/2009 1435 Run 1 150.5

131 3/21/08 5:45 1005.4 1005.3 4/1/2009 1600 Run 2 152.0

132 3/21/08 6:45 957.8 957.7 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 8:45 987.4 839.8 4/2/2009 829 Run 1 235.0

135 3/21/08 9:45 1008.3 907.8 4/2/2009 932 Run 2 231.6

136 3/21/08 10:45 991.0 961.3 4/2/2009 1100 Run 3 236.1

137 3/21/08 11:45 970.3 970.2 Stack D

138 3/21/08 12:45 979.2 979.1 4/2/2009 1249 Run 1 283.8

139 3/21/08 13:45 982.8 982.7 4/2/2009 1425 Run 2 281.0

140 3/21/08 14:45 945.6 945.5 4/2/2009 1500 Run 3 288.4

141 3/21/08 15:45 937.5 937.4

142 3/21/08 16:45 968.5 968.4

143 3/21/08 17:45 1010.9 1010.8

144 3/21/08 18:45 1004.3 1004.2

145 3/21/08 19:45 972.8 972.6

146 3/21/08 20:45 989.3 989.1

147 3/21/08 21:45 1006.4 1006.3

148 3/21/08 22:45 1010.0 1009.9

149 3/21/08 23:45 1003.5 1003.4

150 3/22/08 0:45 1000.3 1000.2

151 3/22/08 1:45 984.3 961.3

152 3/22/08 2:45 967.7 967.5

153 3/22/08 3:45 972.4 972.3

154 3/22/08 4:45 1002.0 1001.8

155 3/22/08 5:45 989.0 988.8

156 3/22/08 6:45 1011.3 1011.2

157 3/22/08 7:45 990.7 911.9

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.

780 840 900 960 1020

3 5

3 0

2 5

2 0

1 5

1 0

5

0

N O x , lb / h r

Frequency

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 e 

Draft December 2011
DEPARTMENT: 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 Environmental 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 NOX 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 ArcelorMittal, Cliffs Natural Resources, and US Steel; Cliffs Natural Resources is the 

managing agent. 

The major steps in taconite pellet production include taconite 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 phases. Phase I included two Dravo-Lurgi straight grate indurating furnaces. 

Construction of the phase began in 1974 and operation began in 1976. A third Dravo-Lurgi straight grate indurating 

furnace was added in Phase II. Construction of Phase II began in 1976, with operation beginning in 1979. 

The three pellet indurating furnaces are functionally equivalent. The average production of the three furnaces is roughly 

equivalent. While the facility is capable of producing 9 million 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 natural 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 past, the facility evaluated other fuels including wood and oat hulls.) 

 

Draft December 2011
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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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 for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions 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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 NOX BART limit consistent with that determination 

are: 

Emission Unit Name EU Number Control 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 NOX BART determination for this unit, as documented in Appendix 9.3 of the December 2009 Regional Haze 

SIP submittal, is good combustion practices and implementation of furnace energy efficiency projects in 2005 and 2006. 

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 HTC entered into an Administrative Order, under which HTC provided additional NOX emission 

information to the MPCA. 

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NOX emission information provided by HTC. Extensive stack tests were conducted using Method 

7E. Initial stack tests were conducted in 2007 and 2008, and covered the entire range of the plant’s operating conditions. 

Stack tests conducted in 2010 (July, October, November, December) were split to reflect the plant’s two main operating 

conditions: producing standard pellets and producing high compression pellets. 

Draft December 2011
Under the previously mentioned Administrative Order, HTC was required to collect “a minimum of 150 one-hour data 

points under the range of [furnace] operating parameters that influence NOX 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 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 calculating 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 ൌ Χത ൅ ሾݐ െ ݐݏܽݐ ൈ ߪ ൈ ඨሺ

1

30 ൅

1

ሻሿݐ݊ݑ݋ܿ

• Where Χത and σ are, respectively, the mean and standard deviation of the sample of hourly-averaged NOX

data points; 

• The t-stat is the 2-tail percentage point of the t-distribution with a level of significance of 0.01 and the 

appropriate degrees of freedom; and 

• ටሺ ଵ

ଷ଴

൅ ଵ

௖௢௨௡௧ሻ 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 sample 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 NOX 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 

Draft December 2011
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 relatively 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 burner 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 believes that using the lower burner is the main operating scenario. The benefit of 

Draft December 2011
using the lower burner, when firing with natural gas, is a slight fuel saving with an apparent reduction in NOX formation 

and emissions. Based on the data, it appears 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 that CEMS are necessary to monitor 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 for 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 ൌ Χത ൅ ሾݖ െ ݐݏܽݐ ൈ ߪ ൈ ඨሺ

1

720 ൅

1

ሻሿݐ݊ݑ݋ܿ

 After reviewing stack test data provided by HTC, the MPCA has determined that appropriate BART NOX limits are: 

Unit BART NOX 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 concerns that any one stack test, 

even an extended stack test, cannot capture all 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 sample data points as a representative population, from which 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 overall “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. The MPCA then looked at this highest standard error, and 

used that standard error (se) and the mean of the original data point sample 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 NOX

stack testing, simultaneously measured for 30 hourly data points. Once CEMS are installed on Line 2, those monitors will 

be used for compliance. CEMS are to be installed and certified within 14 months of the effective date of the 

Administrative Order implementing the BART limits. 

Draft December 2011
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 9:00 444.0 10/13/10 17:00 423.2 10/24/07 19:34 384.5

7/16/10 10:00 446.1 10/13/10 18:00 418.1 10/25/07 12:10 355.0

7/16/10 11:00 435.7 10/13/10 19:00 414.2 10/25/07 13:10 356.3

7/16/10 12:00 429.7 10/13/10 20:00 418.9 10/25/07 14:10 355.5

7/16/10 13:00 427.1 10/13/10 21:00 404.5 10/25/07 14:47 352.5

7/16/10 14:00 422.4 10/13/10 22:00 415.4 10/25/07 15:47 349.9

7/16/10 16:00 430.7 10/13/10 23:00 416.9 10/25/07 16:47 348.4

7/16/10 17:00 281.4 10/14/10 0:00 403.1 10/25/07 17:47 340.2

7/16/10 18:00 401.3 10/14/10 1:00 414.7 10/25/07 18:47 335.4

7/16/10 19:00 432.2 10/14/10 2:00 416.7 10/25/07 19:47 337.2

7/16/10 20:00 439.6 10/14/10 3:00 408.4 10/25/07 20:47 350.4

7/16/10 21:00 440.6 10/14/10 4:00 415.0 10/25/07 21:47 343.3

7/16/10 22:00 440.2 10/14/10 5:00 409.1 10/25/07 22:47 337.0

7/16/10 23:00 436.0 10/14/10 6:00 409.1 10/25/07 23:47 333.2

7/17/10 0:00 429.4 10/14/10 7:00 414.8 10/26/07 0:47 335.3

7/17/10 1:00 441.4 10/14/10 8:00 412.4 10/26/07 1:47 334.0

7/17/10 2:00 434.9 10/14/10 10:00 408.5 10/26/07 2:47 337.6

7/17/10 3:00 436.3 10/14/10 11:00 397.5 10/26/07 3:47 329.4

7/17/10 4:00 438.0 10/14/10 12:00 400.1 10/26/07 4:47 339.7

7/17/10 5:00 435.3 10/14/10 13:00 400.0 10/26/07 5:47 336.9

7/17/10 6:00 431.4 10/14/10 14:00 388.4 10/26/07 6:47 336.9

7/17/10 7:00 432.0 10/14/10 15:00 391.6 10/26/07 7:47 347.2

7/17/10 8:00 430.4 10/14/10 16:00 386.2 10/26/07 8:47 365.3

7/17/10 9:00 443.2 10/14/10 17:00 384.0 10/26/07 9:14 359.7

7/17/10 10:00 434.0 10/14/10 18:00 389.0 10/26/07 11:54 350.5

7/17/10 11:00 441.7 10/14/10 19:00 367.6 10/26/07 12:54 351.9

7/17/10 12:00 444.3 10/14/10 20:00 392.2 10/26/07 13:54 347.9

7/17/10 13:00 449.8 10/14/10 21:00 400.9 10/26/07 14:54 349.4

7/17/10 14:00 437.0 10/14/10 22:00 396.4 10/26/07 15:54 349.3

7/17/10 15:00 424.9 10/14/10 23:00 398.1 10/26/07 16:54 364.3

7/17/10 16:00 430.6 10/15/10 0:00 397.5 10/26/07 17:54 363.5

7/17/10 17 00 7/17/10 17:00 433 0. 10/15/10 1 00 10/15/10 1:00 398 2. 10/26/07 18:5 10/26/07 18 54 367 7.

7/17/10 18:00 434.5 10/15/10 2:00 389.3 10/26/07 19:54 364.6

7/17/10 19:00 431.6 10/15/10 3:00 395.6 10/26/07 20:54 371.0

7/17/10 20:00 420.0 10/15/10 4:00 389.6 10/26/07 21:54 367.0

7/17/10 21:00 430.5 10/15/10 5:00 383.8 10/26/07 22:54 368.0

7/17/10 22:00 431.9 10/15/10 6:00 388.0 10/26/07 23:54 367.9

7/17/10 23:00 426.8 10/15/10 7:00 390.3 10/27/07 0:54 371.3

7/18/10 1:00 418.8 10/15/10 8:00 390.9 10/27/07 1:54 369.4

7/18/10 2:00 425.6 10/15/10 9:00 383.5 10/27/07 2:54 372.5

7/18/10 3:00 418.8 10/15/10 10:00 379.0 10/27/07 3:54 376.3

7/18/10 4:00 405.4 10/15/10 11:00 382.2 10/27/07 4:54 384.2

7/18/10 5:00 402.0 10/15/10 12:00 377.4 10/27/07 5:54 378.0

7/18/10 6:00 419.1 10/15/10 14:00 368.8 10/27/07 6:54 378.1

7/18/10 7:00 411.5 10/15/10 15:00 380.8 10/27/07 7:54 462.1

7/18/10 8:00 412.9 10/15/10 16:00 373.8 10/27/07 8:54 483.1

7/18/10 9:00 418.9 10/15/10 17:00 339.7 10/27/07 11:04 453.5

7/18/10 10:00 419.5 10/15/10 18:00 348.2 10/27/07 12:04 485.9

7/18/10 11:00 420.1 10/15/10 19:00 386.0 10/27/07 13:04 481.5

7/18/10 12:00 423.5 10/15/10 20:00 380.5 10/27/07 14:04 476.3

7/18/10 13:00 424.4 10/15/10 21:00 378.4 10/27/07 15:04 478.2

7/18/10 14:00 419.8 10/15/10 22:00 386.6 10/27/07 16:04 476.1

7/18/10 15:00 421.9 10/15/10 23:00 400.2 10/27/07 17:04 495.5

7/18/10 16:00 360.9 10/16/10 0:00 398.4 10/27/07 18:04 493.9

7/18/10 18:00 423.8 10/16/10 1:00 392.6 10/27/07 19:04 504.7

7/18/10 19:00 420.3 10/16/10 2:00 396.5 10/27/07 20:04 502.6

7/18/10 20:00 424.6 10/16/10 3:00 389.1 10/27/07 21:04 499.4

7/18/10 21:00 245.2 10/16/10 4:00 382.4 10/27/07 22:04 503.5

7/18/10 22:00 388.3 10/16/10 5:00 389.4 10/27/07 23:04 503.7

7/18/10 23:00 427.6 10/16/10 6:00 396.6 10/28/07 0:04 506.9

7/19/10 0:00 429.4 10/16/10 8:00 412.5 10/28/07 0:42 499.8

Draft December 2011
7/19/10 1:00 433.7 10/16/10 9:00 371.7 10/28/07 21:27 364.0

7/19/10 2:00 432.6 10/16/10 10:00 391.9 10/28/07 22:27 357.8

7/19/10 3:00 432.1 10/16/10 11:00 404.7 10/28/07 23:27 346.2

7/19/10 4:00 439.4 10/16/10 12:00 399.9 10/29/07 0:27 345.7

7/19/10 5:00 438.0 10/16/10 13:00 385.7 10/29/07 1:27 339.1

7/19/10 6:00 437.3 10/16/10 14:00 380.3 10/29/07 2:27 345.9

7/19/10 7:00 425.3 10/16/10 15:00 379.6 10/29/07 3:27 349.2

7/19/10 8:00 443.8 10/16/10 16:00 387.4 10/29/07 4:27 348.8

7/19/10 10:00 441.5 10/16/10 17:00 376.4 10/29/07 5:27 343.5

7/19/10 11:00 437.6 10/16/10 18:00 379.8 10/29/07 6:27 347.7

7/19/10 12:00 428.9 10/16/10 19:00 383.0 10/29/07 7:59 320.3

7/19/10 13:00 414.3 10/16/10 20:00 383.6 10/29/07 9:59 333.9

7/19/10 14:00 425.8 10/16/10 21:00 386.4 10/29/07 10:59 329.1

7/19/10 15:00 431.1 10/16/10 22:00 373.9 10/29/07 11:59 326.2

7/19/10 16:00 427.6 10/16/10 23:00 313.5 10/29/07 12:59 331.1

7/19/10 17:00 424.3 10/17/10 0:00 372.6 10/29/07 13:59 327.4

7/19/10 18:00 423.6 10/17/10 1:00 382.1 10/29/07 14:59 327.3

7/19/10 19:00 419.5 10/17/10 2:00 407.6 10/29/07 15:59 321.6

7/19/10 20:00 429.4 10/17/10 3:00 410.4 10/29/07 16:59 268.2

7/19/10 21:00 208.0 10/17/10 4:00 396.5 10/29/07 17:59 337.1

7/19/10 22:00 272.7 10/17/10 5:00 275.7 10/29/07 18:59 323.1

7/19/10 23:00 456.4 10/17/10 6:00 359.9 10/29/07 19:59 327.7

7/20/10 0:00 451.1 10/17/10 7:00 390.1 10/29/07 20:59 325.8

7/20/10 1:00 456.0 10/17/10 8:00 389.0 10/29/07 21:59 332.3

7/20/10 2:00 456.4 10/17/10 9:00 383.1 10/29/07 22:59 333.1

7/20/10 3:00 465.2 10/17/10 10:00 393.1 10/29/07 23:59 327.8

7/20/10 4:00 460.7 10/17/10 11:00 391.1 10/30/07 0:59 330.4

7/20/10 5:00 455.1 10/17/10 12:00 390.6 10/30/07 1:59 335.1

7/20/10 6:00 454.2 10/17/10 13:00 391.7 10/30/07 2:59 327.5

7/20/10 7:00 456.0 10/17/10 14:00 387.9 10/30/07 3:59 318.0

7/20/10 8:00 246.6 10/17/10 15:00 389.2 10/30/07 4:59 310.5

7/20/10 10:00 411.9 10/17/10 17:00 396.2 10/30/07 5:29 304.3

7/20/10 11:00 441.3 10/17/10 18:00 389.6 10/30/07 10:40 452.0

7/20/10 12:00 445.2 10/17/10 19:00 387.4 10/30/07 11:40 437.1

7/20/10 13:00 380.2 10/17/10 20:00 387.4 10/30/07 12:40 432.7

7/20/10 14:00 444.7 10/17/10 21:00 388.5 10/30/07 13:40 419.0

7/20/10 15 00 7/20/10 15:00 450 2. 10/17/10 22 00 10/17/10 22:00 386 1. 10/30/07 14:4 10/30/07 14 40 424 1.

7/20/10 16:00 449.9 10/17/10 23:00 378.5 10/30/07 15:40 382.5

7/20/10 17:00 445.4 10/18/10 0:00 375.6 10/30/07 16:40 390.4

7/20/10 18:00 442.4 10/18/10 1:00 383.6 10/30/07 17:40 380.1

7/20/10 19:00 447.6 10/18/10 2:00 384.0 10/30/07 18:40 386.7

7/20/10 20:00 446.6 10/18/10 3:00 387.8 10/30/07 19:40 388.1

7/20/10 21:00 445.9 10/18/10 4:00 382.8 10/30/07 20:40 391.1

7/20/10 22:00 443.4 10/18/10 5:00 383.0 10/30/07 21:40 393.3

7/20/10 23:00 448.4 10/18/10 6:00 381.5 10/30/07 22:40 392.2

7/21/10 0:00 449.7 10/18/10 7:00 381.2 10/30/07 23:40 370.8

7/21/10 1:00 445.3 10/18/10 8:00 383.2 10/31/07 0:40 376.6

7/21/10 2:00 442.2 10/18/10 9:00 383.4 10/31/07 7:49 400.4

7/21/10 3:00 449.1 10/18/10 11:00 385.6 10/31/07 9:30 398.7

7/21/10 4:00 447.5 10/18/10 12:00 387.5 10/31/07 11:30 411.5

7/21/10 5:00 454.7 10/18/10 13:00 386.2 10/31/07 12:30 400.2

7/21/10 6:00 451.4 10/18/10 14:00 380.9 10/31/07 13:30 398.5

7/21/10 7:00 451.3 10/18/10 15:00 370.0 10/31/07 14:30 409.9

7/21/10 8:00 446.1 10/18/10 16:00 364.6 10/31/07 14:45 401.1

7/21/10 9:00 449.8 10/18/10 17:00 371.0 10/31/07 15:45 401.1

7/21/10 10:00 447.7 10/18/10 18:00 366.3 10/31/07 16:35 406.3

7/21/10 11:00 455.8 10/18/10 19:00 360.5 10/31/07 20:11 442.8

7/21/10 12:00 467.1 10/18/10 20:00 364.9 10/31/07 21:11 467.6

7/21/10 13:00 462.0 10/18/10 21:00 360.9 10/31/07 22:11 472.7

7/21/10 14:00 456.3 10/18/10 22:00 368.5 10/31/07 23:11 493.4

7/21/10 15:00 457.3 10/18/10 23:00 360.1 11/1/07 0:11 488.4

7/21/10 16:00 464.4 10/19/10 0:00 346.4 11/1/07 1:11 486.7

7/21/10 17:00 461.1 10/19/10 1:00 344.7 11/1/07 2:11 482.6

7/21/10 18:00 467.7 10/19/10 2:00 334.8 11/1/07 3:11 491.3

7/21/10 19:00 470.8 10/19/10 3:00 330.5 11/1/07 4:11 489.9

7/21/10 20:00 467.5 10/19/10 4:00 334.3 11/1/07 5:11 490.9

Draft December 2011
7/21/10 21:00 467.1 10/19/10 5:00 331.9 11/1/07 6:11 481.9

7/21/10 22:00 460.5 10/19/10 6:00 323.4 11/1/07 6:30 510.5

7/21/10 23:00 463.8 10/19/10 7:00 325.9 11/1/07 7:30 411.5

7/22/10 0:00 463.9 10/19/10 8:00 326.9 11/1/07 8:30 365.6

7/22/10 1:00 464.2 10/19/10 9:00 320.1 11/1/07 10:14 370.3

7/22/10 2:00 458.9 10/19/10 10:00 285.0 11/1/07 11:14 360.4

7/22/10 3:00 458.9 10/19/10 13:00 320.1 11/1/07 12:14 364.4

7/22/10 4:00 460.1 10/19/10 14:00 348.2 11/1/07 13:14 354.9

7/22/10 5:00 450.7 10/19/10 15:00 345.1 11/1/07 14:14 357.8

7/22/10 6:00 446.0 10/19/10 16:00 351.0 11/1/07 15:14 364.5

7/22/10 7:00 455.1 10/19/10 17:00 354.9 11/1/07 16:14 359.0

7/22/10 8:00 456.7 10/19/10 18:00 355.4 11/1/07 17:14 362.8

7/22/10 9:00 450.3 10/19/10 19:00 359.7 11/1/07 18:14 364.5

7/22/10 10:00 447.1 10/19/10 20:00 361.0 11/1/07 19:14 381.7

7/22/10 11:00 445.3 10/19/10 21:00 353.4 11/1/07 20:14 406.0

7/22/10 12:00 448.0 10/19/10 22:00 368.1 11/1/07 21:14 434.4

7/22/10 13:00 446.2 10/19/10 23:00 359.8 11/1/07 22:14 444.7

7/22/10 14:00 446.5 10/20/10 0:00 357.3 11/1/07 23:14 436.8

7/22/10 15:00 444.0 10/20/10 1:00 361.4 11/2/07 0:14 441.6

7/22/10 16:00 444.1 10/20/10 2:00 360.6 11/2/07 1:14 446.1

7/22/10 17:00 443.6 10/20/10 3:00 359.3 11/2/07 2:14 412.5

7/22/10 18:00 449.5 10/20/10 4:00 352.5 11/2/07 3:14 407.2

7/22/10 19:00 446.6 10/20/10 5:00 349.3 11/2/07 4:14 441.3

7/22/10 20:00 435.2 10/20/10 6:00 350.6 11/2/07 5:14 430.8

7/22/10 21:00 373.0 10/20/10 7:00 353.2 11/2/07 6:14 433.2

7/22/10 22:00 439.6 10/20/10 8:00 365.3 11/2/07 7:14 413.0

7/22/10 23:00 436.1 10/20/10 10:00 375.6 11/2/07 7:29 314.3

7/23/10 0:00 431.5 10/20/10 11:00 376.5 11/2/07 8:00 318.5

7/23/10 1:00 432.6 10/20/10 12:00 378.1 11/2/07 9:35 319.2

7/23/10 2:00 440.4 10/20/10 13:00 382.3 11/2/07 10:35 314.6

7/23/10 3:00 439.4 10/20/10 14:00 364.3 11/2/07 11:35 320.7

7/23/10 4:00 424.4 10/20/10 15:00 366.3 11/2/07 12:35 320.0

7/23/10 5:00 235.8 10/20/10 16:00 373.9 11/2/07 13:35 328.3

7/23/10 6:00 422.5 10/20/10 17:00 376.0 11/2/07 14:35 322.9

7/23/10 7:00 440.6 10/20/10 18:00 377.9 11/2/07 14:59 329.6

7/23/10 8:00 438.4 10/20/10 19:00 373.6 11/2/07 15:59 458.6

7/23/10 9 00 7/23/10 9:00 435 0. 10/20/10 20 00 10/20/10 20:00 381 5. 11/2/07 16:2 11/2/07 16 29 476 4.

7/23/10 10:00 422.3 10/20/10 21:00 370.2 11/2/07 17:29 464.1

7/23/10 11:00 410.5 10/20/10 22:00 364.9 11/2/07 18:29 477.6

7/23/10 12:00 418.3 10/20/10 23:00 368.2 11/2/07 19:29 474.3

7/23/10 13:00 417.8 10/21/10 0:00 367.5 11/2/07 20:29 462.0

7/23/10 14:00 414.2 10/21/10 1:00 365.0 11/2/07 21:29 472.0

7/23/10 15:00 407.7 10/21/10 2:00 368.3 11/2/07 22:29 472.0

7/23/10 16:00 392.3 10/21/10 3:00 361.4 11/2/07 23:29 454.0

7/23/10 17:00 400.5 10/21/10 4:00 382.9 11/3/07 0:29 469.9

7/23/10 18:00 408.0 10/21/10 5:00 388.2 11/3/07 1:29 473.1

7/23/10 19:00 407.3 10/21/10 6:00 388.8 11/3/07 2:29 465.3

7/23/10 20:00 421.2 10/21/10 7:00 384.7 11/3/07 3:29 468.0

7/23/10 21:00 413.0 10/21/10 8:00 385.4 11/3/07 4:29 458.0

7/23/10 22:00 416.6 10/21/10 9:00 376.9 11/3/07 5:29 473.5

7/23/10 23:00 412.5 10/21/10 10:00 369.8

7/24/10 0:00 411.1 10/21/10 12:00 359.6

7/24/10 1:00 403.0 10/21/10 13:00 359.3

7/24/10 2:00 406.5 10/21/10 14:00 366.2

7/24/10 3:00 410.8 10/21/10 15:00 362.4

7/24/10 4:00 410.5 10/21/10 16:00 362.6

7/24/10 5:00 404.0 10/21/10 17:00 370.0

7/24/10 6:00 409.3 10/21/10 18:00 368.5

7/24/10 7:00 402.1 10/21/10 19:00 364.6

7/24/10 8:00 397.7 10/21/10 20:00 365.3

7/24/10 9:00 402.1 10/21/10 21:00 364.5

7/24/10 10:00 409.9 10/21/10 22:00 358.3

7/24/10 11:00 408.3 10/21/10 23:00 362.3

10/22/10 0:00 351.7

10/22/10 1:00 357.6

10/22/10 2:00 346.9

Draft December 2011
10/22/10 3:00 351.6

10/22/10 4:00 347.6

10/22/10 5:00 349.8

10/22/10 6:00 352.7

10/22/10 7:00 351.7

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 470.84 Max 423.20 Max 510.49

Min 207.96 Min 275.72 Min 268.19

t0.05, c-1 1.973

t0.05, c-1 1.972t0.05, 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% 401.24 t0.01, c-1 2.602 t0.01, c-1 2.601 t0.01, 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% 404.09

Draft December 2011
Line 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 17:00 607.7 11/6/10 15:00 741.8 11/16/10 13:00 324.1 11/27/10 13:00 294.01

10/22/10 18:00 610.0 11/6/10 16:00 755.8 11/16/10 14:00 318.3 11/27/10 14:00 295.70

10/22/10 19:00 586.3 11/6/10 17:00 763.4 11/16/10 15:00 318.2 11/27/10 15:00 301.17

10/22/10 20:00 618.8 11/6/10 18:00 760.1 11/16/10 16:00 316.6 11/27/10 16:00 300.94

10/22/10 21:00 628.1 11/6/10 19:00 765.2 11/16/10 17:00 319.0 11/27/10 17:00 301.50

10/22/10 22:00 601.8 11/6/10 20:00 760.5 11/16/10 18:00 320.1 11/27/10 18:00 302.76

10/22/10 23:00 599.0 11/6/10 21:00 745.4 11/16/10 19:00 317.5 11/27/10 19:00 299.37

10/23/10 0:00 602.0 11/6/10 22:00 746.3 11/16/10 20:00 315.4 11/27/10 20:00 298.86

10/23/10 1:00 594.2 11/6/10 23:00 759.8 11/16/10 21:00 317.8 11/27/10 21:00 298.83

10/23/10 2:00 589.4 11/7/10 0:00 738.3 11/16/10 22:00 326.7 11/27/10 22:00 297.09

10/23/10 3:00 590.2 11/7/10 1:00 741.3 11/16/10 23:00 327.7 11/27/10 23:00 298.86

10/23/10 4:00 618.4 11/7/10 2:00 745.2 11/17/10 0:00 332.5 11/28/10 0:00 297.00

10/23/10 5:00 612.4 11/7/10 3:00 756.0 11/17/10 1:00 332.9 11/28/10 1:00 294.28

10/23/10 12:00 557.9 11/7/10 4:00 751.1 11/17/10 2:00 333.8 11/28/10 2:00 293.72

10/23/10 13:00 566.5 11/7/10 5:00 746.3 11/17/10 3:00 332.2 11/28/10 3:00 294.03

10/23/10 14:00 579.2 11/7/10 6:00 750.4 11/17/10 4:00 335.3 11/28/10 4:00 294.99

10/23/10 15:00 572.2 11/7/10 7:00 756.4 11/17/10 5:00 336.4 11/28/10 5:00 291.93

10/23/10 16:00 571.3 11/7/10 8:00 749.9 11/17/10 6:00 333.8 11/28/10 6:00 294.31

10/23/10 17:00 571.0 11/7/10 9:00 755.0 11/17/10 7:00 336.2 11/28/10 7:00 293.42

10/23/10 18:00 553.6 11/7/10 10:00 753.1 11/17/10 8:00 333.2 11/28/10 8:00 293.49

10/23/10 19:00 561.6 11/7/10 11:00 740.4 11/17/10 9:00 341.8 11/28/10 9:00 291.37

10/23/10 20:00 579.4 11/7/10 12:00 737.1 11/17/10 10:00 336.0 11/28/10 10:00 290.46

10/23/10 21:00 572.4 11/7/10 13:00 740.2 11/17/10 11:00 336.0 11/28/10 11:00 289.10

10/23/10 22:00 555.2 11/7/10 14:00 744.7 11/17/10 12:00 336.6 11/28/10 12:00 290.27

10/23/10 23:00 575.5 11/7/10 15:00 748.2 11/17/10 13:00 322.8 11/28/10 14:00 284.77

10/24/10 0:00 547.2 11/7/10 16:00 740.1 11/17/10 14:00 306.8 11/28/10 15:00 277.78

10/24/10 1:00 550.5 11/7/10 17:00 744.2 11/17/10 15:00 324.1 11/28/10 16:00 292.63

10/24/10 2:00 550.6 11/7/10 18:00 748.4 11/17/10 16:00 328.6 11/28/10 17:00 294.24

10/24/10 3:00 551.9 11/7/10 19:00 741.0 11/17/10 17:00 297.1 11/28/10 18:00 294.31

10/24/10 4:00 572.1 11/7/10 20:00 732.0 11/17/10 18:00 309.7 11/28/10 19:00 294.50

10/24/10 5:00 568.6 11/7/10 21:00 728.7 11/17/10 19:00 325.7 11/28/10 20:00 292.53

10/24/10 6 00 10/24/10 6:00 566 7. 11/7/10 22:0 11/7/10 22 00 732 1. 11/17/10 20:0 11/17/10 20 00 329 2. 11/28/10 21:0 11/28/10 21 00 290 94.

10/24/10 7:00 565.8 11/7/10 23:00 737.1 11/17/10 21:00 328.4 11/28/10 22:00 286.85

10/24/10 8:00 569.4 11/8/10 0:00 722.3 11/17/10 22:00 330.0 11/28/10 23:00 289.04

10/24/10 9:00 558.1 11/8/10 1:00 737.4 11/17/10 23:00 331.5 11/29/10 0:00 287.60

10/24/10 10:00 558.2 11/8/10 2:00 728.2 11/18/10 0:00 327.9 11/29/10 1:00 287.98

10/24/10 11:00 563.7 11/8/10 3:00 727.5 11/18/10 1:00 327.7 11/29/10 2:00 289.12

10/24/10 12:00 560.5 11/8/10 4:00 729.5 11/18/10 2:00 327.4 11/29/10 3:00 290.45

10/24/10 13:00 557.5 11/8/10 5:00 733.5 11/18/10 3:00 328.3 11/29/10 4:00 290.20

10/24/10 15:00 550.3 11/8/10 6:00 729.5 11/18/10 4:00 331.6 11/29/10 5:00 290.79

10/24/10 16:00 553.4 11/8/10 7:00 726.8 11/18/10 5:00 331.0 11/29/10 6:00 292.44

10/24/10 17:00 554.7 11/8/10 8:00 733.0 11/18/10 6:00 330.9 11/29/10 7:00 293.19

10/24/10 18:00 551.6 11/8/10 9:00 738.8 11/18/10 7:00 328.9 11/29/10 8:00 293.17

10/24/10 19:00 554.1 11/8/10 11:00 726.8 11/18/10 8:00 330.6 11/29/10 9:00 294.64

10/24/10 20:00 561.3 11/8/10 12:00 675.8 11/18/10 9:00 331.6 11/29/10 10:00 293.10

10/24/10 21:00 561.5 11/8/10 13:00 644.6 11/18/10 10:00 331.6 11/29/10 11:00 291.23

10/24/10 22:00 560.1 11/8/10 14:00 651.9 11/18/10 11:00 334.6 11/29/10 12:00 288.11

10/24/10 23:00 555.8 11/8/10 15:00 654.8 11/18/10 12:00 333.5 11/29/10 13:00 290.12

10/25/10 0:00 561.9 11/8/10 16:00 657.6 11/18/10 13:00 335.8 11/29/10 14:00 290.06

10/25/10 1:00 557.6 11/8/10 17:00 663.5 11/18/10 14:00 327.0 11/29/10 15:00 289.88

10/25/10 2:00 557.0 11/8/10 18:00 687.4 11/18/10 15:00 328.8 11/29/10 16:00 288.08

10/25/10 3:00 553.0 11/8/10 19:00 683.2 11/18/10 16:00 327.3 11/29/10 17:00 287.28

10/25/10 4:00 557.6 11/8/10 20:00 711.0 11/18/10 17:00 326.9 11/29/10 18:00 286.60

10/25/10 5:00 560.5 11/8/10 21:00 710.5 11/18/10 18:00 327.3 11/29/10 19:00 285.79

10/25/10 6:00 557.7 11/8/10 22:00 720.2 11/18/10 19:00 319.6 11/29/10 20:00 284.26

10/25/10 7:00 556.9 11/8/10 23:00 728.3 11/19/10 11:00 316.8 11/29/10 21:00 282.00

10/25/10 8:00 554.9 11/9/10 0:00 658.6 11/19/10 12:00 321.2 11/30/10 10:00 240.81

10/25/10 9:00 534.1 11/9/10 1:00 659.2 11/19/10 14:00 327.8 11/30/10 11:00 75.10

10/25/10 18:00 564.7 11/9/10 2:00 650.6 11/19/10 15:00 332.0 11/30/10 12:00 152.92

10/25/10 19:00 550.8 11/9/10 3:00 653.0 11/19/10 16:00 331.5 11/30/10 13:00 258.28

10/25/10 20:00 553.6 11/9/10 4:00 653.0 11/19/10 17:00 334.3 11/30/10 14:00 259.69

Draft December 2011
10/25/10 21:00 551.0 11/9/10 5:00 648.6 11/19/10 18:00 333.3 11/30/10 15:00 264.81

10/25/10 22:00 552.1 11/9/10 6:00 655.7 11/19/10 19:00 329.3 11/30/10 16:00 267.36

10/25/10 23:00 551.3 11/9/10 7:00 649.0 11/19/10 20:00 328.1 11/30/10 17:00 274.66

10/26/10 0:00 542.7 11/9/10 8:00 660.1 11/19/10 21:00 328.4 11/30/10 18:00 280.10

10/26/10 1:00 542.0 11/9/10 9:00 662.3 11/19/10 22:00 328.9 11/30/10 19:00 283.13

10/26/10 2:00 530.0 11/9/10 11:00 724.5 11/19/10 23:00 333.9 11/30/10 20:00 284.76

10/26/10 3:00 528.8 11/9/10 12:00 721.7 11/20/10 0:00 333.4 11/30/10 21:00 287.89

10/26/10 4:00 524.3 11/9/10 13:00 719.1 11/20/10 1:00 329.8 11/30/10 22:00 287.80

10/26/10 12:00 506.6 11/9/10 14:00 708.0 11/20/10 2:00 333.2 11/30/10 23:00 286.04

10/26/10 13:00 512.6 11/9/10 15:00 715.4 11/20/10 3:00 326.7 12/1/10 0:00 284.30

10/26/10 14:00 558.1 11/9/10 16:00 709.1 11/20/10 4:00 330.6 12/1/10 1:00 284.50

10/26/10 15:00 573.7 11/9/10 17:00 709.8 11/20/10 5:00 331.1 12/1/10 2:00 288.79

10/26/10 16:00 563.7 11/9/10 18:00 707.6 11/20/10 6:00 336.0 12/1/10 3:00 294.38

10/26/10 17:00 564.4 11/9/10 19:00 636.1 11/20/10 7:00 335.1 12/1/10 4:00 294.33

10/26/10 18:00 549.4 11/9/10 20:00 617.6 11/20/10 8:00 333.6 12/1/10 5:00 295.61

10/26/10 19:00 559.3 11/9/10 21:00 714.1 11/20/10 9:00 340.3 12/1/10 6:00 295.98

10/26/10 20:00 570.5 11/9/10 22:00 713.3 11/20/10 10:00 342.6 12/1/10 7:00 295.42

10/26/10 21:00 555.1 11/9/10 23:00 709.9 11/20/10 11:00 342.2 12/1/10 8:00 295.07

10/26/10 22:00 547.7 11/10/10 0:00 716.0 11/20/10 12:00 342.2 12/1/10 9:00 297.87

10/26/10 23:00 562.6 11/10/10 1:00 723.0 11/20/10 13:00 349.6 12/1/10 10:00 297.95

10/27/10 0:00 567.8 11/10/10 2:00 714.9 11/20/10 14:00 350.8 12/1/10 11:00 300.92

10/27/10 1:00 565.3 11/10/10 3:00 725.0 11/20/10 15:00 332.9 12/1/10 12:00 296.96

10/27/10 2:00 573.0 11/10/10 4:00 726.5 11/20/10 16:00 321.0 12/1/10 13:00 298.10

10/27/10 3:00 568.5 11/10/10 5:00 728.1 11/20/10 17:00 351.1 12/1/10 14:00 296.08

10/27/10 4:00 583.7 11/10/10 6:00 724.8 11/20/10 18:00 346.3 12/1/10 15:00 294.52

10/27/10 5:00 573.1 11/10/10 7:00 724.3 11/20/10 19:00 349.4 12/1/10 16:00 294.70

10/27/10 6:00 564.8 11/10/10 8:00 721.5 11/20/10 20:00 348.9 12/1/10 17:00 296.88

10/27/10 7:00 562.8 11/10/10 9:00 719.8 11/20/10 21:00 346.3 12/1/10 18:00 300.85

10/27/10 8:00 558.4 11/10/10 10:00 704.2 11/20/10 22:00 348.7 12/1/10 19:00 299.29

10/27/10 9:00 559.2 11/10/10 11:00 694.8 11/20/10 23:00 349.0 12/1/10 20:00 299.19

10/27/10 10:00 561.2 11/10/10 12:00 692.4 11/21/10 0:00 349.1 12/1/10 21:00 300.24

10/27/10 11:00 562.5 11/10/10 13:00 695.5 11/21/10 1:00 348.5 12/1/10 22:00 298.89

10/27/10 12:00 545.7 11/10/10 14:00 692.5 11/21/10 2:00 349.9 12/1/10 23:00 301.31

10/27/10 13:00 540.4 11/10/10 15:00 692.0 11/21/10 3:00 354.4 12/2/10 0:00 301.31

10/27/10 14:00 543.7 11/10/10 16:00 707.1 11/21/10 4:00 355.8 12/2/10 1:00 299.72

10/27/10 15:00 538.5 11/10/10 17:00 717.3 11/21/10 5:00 352.5 12/2/10 2:00 297.82

10/27/10 16 00 10/27/10 16:00 529 4. 11/10/10 18:0 11/10/10 18 00 722 6. 11/21/10 6:0 11/21/10 6 00 350 8. 12/2/10 3:0 12/2/10 3 00 295 79.

10/27/10 17:00 526.6 11/10/10 19:00 705.5 11/21/10 7:00 348.6 12/2/10 4:00 299.70

10/27/10 18:00 537.0 11/10/10 20:00 707.6 11/21/10 8:00 350.4 12/2/10 5:00 267.51

10/27/10 19:00 531.5 11/10/10 21:00 716.6 11/21/10 9:00 353.4 12/2/10 6:00 226.65

10/27/10 20:00 531.7 11/10/10 22:00 714.1 11/21/10 10:00 351.2 12/2/10 7:00 196.94

10/27/10 21:00 521.3 11/10/10 23:00 713.3 11/21/10 11:00 347.4 12/2/10 8:00 131.39

10/27/10 22:00 520.6 11/11/10 0:00 713.2 11/21/10 12:00 347.6 12/2/10 9:00 273.71

10/27/10 23:00 522.0 11/11/10 1:00 711.4 11/21/10 13:00 348.7 12/2/10 10:00 281.69

10/28/10 0:00 517.2 11/11/10 2:00 705.9 11/21/10 15:00 342.9 12/2/10 11:00 42.20

10/28/10 1:00 513.8 11/11/10 3:00 711.6 11/21/10 16:00 340.2 12/2/10 12:00 207.76

10/28/10 2:00 512.3 11/11/10 4:00 720.1 11/21/10 17:00 334.7 12/2/10 13:00 275.18

10/28/10 3:00 509.9 11/11/10 5:00 726.8 11/21/10 18:00 337.0 12/2/10 14:00 288.46

10/28/10 4:00 504.8 11/11/10 6:00 739.4 11/21/10 19:00 333.9 12/2/10 15:00 287.37

10/28/10 5:00 515.4 11/11/10 7:00 740.5 11/21/10 20:00 331.2 12/2/10 16:00 283.87

10/28/10 6:00 510.5 11/11/10 8:00 749.8 11/22/10 15:00 135.0 12/2/10 17:00 283.11

10/28/10 7:00 497.1 11/11/10 9:00 745.3 11/22/10 16:00 257.9 12/2/10 18:00 281.75

10/28/10 8:00 496.4 11/11/10 10:00 753.0 11/22/10 17:00 262.0 12/2/10 19:00 284.70

10/28/10 9:00 494.4 11/11/10 11:00 743.5 11/22/10 18:00 279.5 12/2/10 20:00 286.48

10/28/10 10:00 511.1 11/11/10 12:00 681.0 11/22/10 19:00 274.9 12/2/10 21:00 288.06

10/28/10 11:00 515.0 11/11/10 13:00 733.3 11/22/10 20:00 286.2 12/2/10 22:00 288.30

10/28/10 12:00 526.3 11/11/10 14:00 723.9 11/22/10 21:00 284.0 12/2/10 23:00 287.67

10/28/10 13:00 515.4 11/11/10 15:00 724.3 11/22/10 22:00 284.5 12/3/10 0:00 288.41

10/28/10 14:00 522.9 11/11/10 16:00 717.8 11/22/10 23:00 285.1 12/3/10 1:00 289.28

10/28/10 15:00 516.0 11/11/10 17:00 660.5 11/23/10 0:00 287.6 12/3/10 2:00 288.28

10/28/10 16:00 509.8 11/11/10 18:00 724.3 11/23/10 1:00 283.9 12/3/10 3:00 290.14

10/28/10 17:00 509.0 11/11/10 19:00 724.1 11/23/10 2:00 283.9 12/3/10 4:00 288.62

10/28/10 18:00 497.0 11/11/10 20:00 720.2 11/23/10 3:00 288.8 12/3/10 5:00 292.51

10/28/10 19:00 488.3 11/11/10 21:00 710.1 11/23/10 4:00 288.0 12/3/10 6:00 291.40

10/28/10 20:00 498.9 11/11/10 22:00 718.2 11/23/10 5:00 291.0 12/3/10 7:00 292.85

10/28/10 21:00 489.8 11/11/10 23:00 714.6 11/23/10 6:00 289.2 12/3/10 8:00 292.49

Draft December 2011
10/28/10 22:00 489.9 11/12/10 0:00 717.1 11/23/10 7:00 287.4 12/3/10 9:00 288.90

10/28/10 23:00 496.3 11/12/10 12:00 748.1 11/23/10 8:00 265.8 12/3/10 10:00 284.46

10/29/10 0:00 492.5 11/12/10 13:00 749.3 11/23/10 9:00 285.1 12/3/10 11:00 286.67

10/29/10 1:00 479.1 11/12/10 14:00 740.6 11/23/10 10:00 293.0 12/3/10 12:00 289.03

10/29/10 2:00 476.1 11/12/10 15:00 612.3 11/23/10 11:00 322.2 12/3/10 13:00 292.24

10/29/10 3:00 472.3 11/12/10 16:00 249.0 11/23/10 12:00 319.6 12/3/10 14:00 292.57

10/29/10 4:00 475.6 11/12/10 17:00 390.3 11/23/10 13:00 325.9 12/3/10 15:00 295.21

10/29/10 5:00 476.6 11/12/10 18:00 676.1 11/23/10 14:00 325.1 12/3/10 16:00 297.02

10/29/10 6:00 452.3 11/12/10 19:00 729.2 11/23/10 15:00 327.6 12/3/10 17:00 299.08

10/29/10 7:00 496.1 11/12/10 20:00 717.0 11/23/10 16:00 331.7 12/3/10 18:00 295.49

10/29/10 8:00 515.0 11/12/10 21:00 720.0 11/23/10 17:00 331.3 12/3/10 19:00 286.90

10/29/10 9:00 572.2 11/12/10 22:00 717.7 11/23/10 18:00 327.6 12/3/10 20:00 285.47

10/29/10 10:00 604.4 11/12/10 23:00 723.4 11/23/10 19:00 327.9 12/3/10 21:00 293.06

10/29/10 12:00 607.4 11/13/10 0:00 728.6 11/23/10 20:00 326.7 12/3/10 22:00 293.72

10/29/10 13:00 630.7 11/13/10 1:00 729.1 11/23/10 21:00 333.0 12/3/10 23:00 291.79

10/29/10 14:00 496.8 11/13/10 2:00 725.0 11/23/10 22:00 332.7 12/4/10 0:00 297.06

10/29/10 15:00 548.3 11/13/10 3:00 724.1 11/23/10 23:00 334.3 12/4/10 1:00 291.40

10/29/10 16:00 457.0 11/13/10 4:00 719.3 11/24/10 0:00 332.8 12/4/10 15:00 295.32

10/29/10 17:00 452.6 11/13/10 5:00 728.1 11/24/10 1:00 333.6 12/4/10 16:00 294.17

10/29/10 18:00 443.4 11/13/10 6:00 734.5 11/24/10 2:00 338.3 12/4/10 17:00 284.49

10/29/10 19:00 437.1 11/13/10 7:00 728.4 11/24/10 3:00 335.3 12/4/10 18:00 291.56

10/29/10 20:00 446.0 11/13/10 8:00 723.7 11/24/10 4:00 338.3 12/4/10 19:00 298.66

10/29/10 21:00 509.5 11/13/10 9:00 729.2 11/24/10 5:00 336.0 12/4/10 20:00 296.42

10/29/10 22:00 587.4 11/13/10 10:00 724.3 11/24/10 6:00 333.4 12/4/10 21:00 286.80

10/29/10 23:00 583.6 11/13/10 11:00 735.6 11/24/10 7:00 336.4 12/4/10 22:00 279.65

10/30/10 0:00 572.1 11/13/10 12:00 746.3 11/24/10 8:00 333.3 12/4/10 23:00 290.35

10/30/10 1:00 562.2 11/13/10 13:00 691.8 11/24/10 9:00 331.5 12/5/10 0:00 283.03

10/30/10 2:00 557.9 11/13/10 14:00 711.1 11/24/10 10:00 330.3 12/5/10 1:00 289.45

10/30/10 3:00 560.3 11/13/10 15:00 711.9 11/24/10 11:00 333.1 12/5/10 2:00 289.76

10/30/10 4:00 564.7 11/13/10 16:00 710.0 11/24/10 12:00 331.1 12/5/10 3:00 290.60

10/30/10 5:00 563.1 11/13/10 17:00 712.7 11/24/10 13:00 326.3 12/5/10 4:00 292.30

10/30/10 6:00 565.4 11/13/10 19:00 708.5 11/24/10 14:00 327.3 12/5/10 5:00 289.77

10/30/10 7:00 579.2 11/13/10 20:00 708.5 11/24/10 15:00 326.8 12/5/10 6:00 291.29

10/30/10 8:00 596.1 11/13/10 21:00 714.0 11/24/10 16:00 326.6 12/5/10 7:00 289.20

10/30/10 9:00 585.8 11/13/10 22:00 705.2 11/24/10 17:00 325.6 12/5/10 8:00 298.59

11/13/10 23:00 710.1 11/24/10 18:00 322.9 12/5/10 9:00 298.98

11/14/10 0 00 11/14/10 0:00 694 3. 11/24/10 19:0 11/24/10 19 00 324 0. 12/5/10 10:0 12/5/10 10 00 293 04.

11/14/10 1:00 709.1 11/24/10 20:00 328.0 12/5/10 11:00 288.44

11/14/10 2:00 701.8 11/24/10 21:00 327.6 12/5/10 12:00 297.17

11/14/10 3:00 714.4 11/24/10 22:00 329.0 12/5/10 13:00 297.72

11/14/10 4:00 705.4 11/24/10 23:00 331.1 12/5/10 14:00 291.15

11/14/10 5:00 709.8 11/25/10 0:00 331.0 12/5/10 15:00 292.23

11/14/10 6:00 709.2 11/25/10 1:00 331.4 12/5/10 16:00 290.92

11/14/10 7:00 707.5 11/25/10 2:00 331.6 12/5/10 17:00 292.91

11/14/10 8:00 700.4 11/25/10 3:00 332.6 12/5/10 18:00 292.11

11/14/10 9:00 707.5 11/25/10 4:00 332.6 12/5/10 19:00 290.62

11/14/10 10:00 725.1 11/25/10 5:00 337.0 12/5/10 20:00 294.14

11/14/10 11:00 704.7 11/25/10 6:00 339.2 12/5/10 21:00 294.32

11/14/10 12:00 705.3 11/25/10 7:00 339.0 12/5/10 22:00 294.48

11/14/10 13:00 719.5 11/25/10 8:00 342.4 12/5/10 23:00 293.22

11/14/10 14:00 726.0 11/25/10 9:00 334.1 12/6/10 0:00 291.59

11/14/10 15:00 716.2 12/6/10 1:00 292.75

12/6/10 2:00 294.70

12/6/10 3:00 288.93

12/6/10 4:00 290.03

12/6/10 5:00 279.35

12/6/10 6:00 272.97

12/6/10 7:00 282.02

12/6/10 8:00 290.52

12/6/10 9:00 306.58

12/6/10 10:00 310.61

12/6/10 11:00 276.40

12/6/10 12:00 306.05

12/6/10 13:00 307.32

12/6/10 14:00 307.39

12/6/10 15:00 309.64

Draft December 2011
Count 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

t0.05, c-1 1.975

t0.05, c-1 1.973t0.05, c-1 1.973t0.05, 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% 719.04 UCL 95% 329.71 UCL 95% 290.05 t0.01, c-1 2.607 t0.01, c-1 2.604 t0.01, c-1 2.604 t0.01, c-1 2.603

UPL 99% 565.69 UPL 99% 737.84 UPL 99% 338.28 UPL 99% 301.40

UCL 99% 553.77 UCL 99% 721.46 UCL 99% 330.82 UCL 99% 291.45

Draft December 2011
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 1.960 441.5

Draft December 2011
Line 2 Information

BART Limit Options

1) Using L2S and L2H Data (2010)

Use of the 2-tail 99% confidence level for the fitted normal patternMean 632.8 2-tail z0.01 2.576 2-tail 99% UCL 

Stdev 94.42 2-tail z0.05 1.960 2-tail 95% UCL Count 341

2) Using the combined L2P, L2S, and L2H Data

Mean 550.7 2-tail 99% UCL Stdev 141.9 2-tail 95% UCL Count 518For predicting the next single data point

2-tail 99% UPL 

2-tail 95% UPL 

For predicting the next 30 data points - representing a 30 data point stack test

2-tail 99% UPL 

2-tail 95% UPL 

For predicting the next 720 data points - representing 30-day rolling average from dai

2-tail 99% UPL 

2-tail 95% UPL 

Draft 
Line 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 1.960 334.6

Draft December 2011
DEPARTMENT: 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 Environmental 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 NOX 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 Gischia; Phone: (218) 226-6076 

1.2 Description of the Facility

Northshore Mining Company’s (NSM) Silver Bay facility is located 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 the facility from Cyprus Minerals in 1994; Cleveland Cliffs now owns and operates the facility. 

NSM has four indurating furnaces. Furnaces 11 and 12 began 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 that 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. 

 

Draft December 2011
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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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 for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions 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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 NOX BART limit consistent with that determination 

is: 

Emission Unit Name EU Number Control 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 NOX BART determinations for these units are documented in Appendix 9.3 of the December 2009 Regional 

Haze SIP submittal. The BART NOX determination for the process boilers is existing design and permitted fuels. The BART 

NOX determination for the indurating furnaces 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 for the indurating 

furnaces. Instead, the MPCA and NSM entered into an Administrative Order, under which NSM provided additional NOX

emission information to the MPCA. 

 

Draft December 2011
2.4 MPCA Determination of the BART Limit

The BART limit for the process boilers was previously determined and is 0.17 lbs NOX/MMBtu heat input; no SO2 limit 

was set as the process boilers burn only natural gas and low sulfur distillate fuel oil. The SO2 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 NOX emission information from the indurating furnaces provided by NSM. Under the previously 

mentioned Administrative Order, NSM was required to collect “a minimum of 150 one-hour data points under the range 

of [furnace] operating parameters that influence NOX 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. 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, while the 2009 tests were shorter (30 data points). 

The BART limit, in the form of a mass emission rate of NOX in lbs/hour for each furnace, was developed based on the 

2008 data, with the 2009 data used to check 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 ൌ Χത ൅ ሾ2.604 ൈ ߪ ഥ ൈ ඨሺ

1

30 ൅

1

176ሻሿ

• Where Χത and ߪത are, respectively, the mean and standard deviation of the sample of 176 hourly-averaged 

NOX 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; 

• ටሺ 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.

 

Draft December 2011
Northshore Mining NOX 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 alleviate 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 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 overall 

“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 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. In the bootstrapping technique, the standard error of datasets of 30 points drawn the new surrogate 

population (built from the mean of each of 2000 randomly selected 30 data point 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% UPLs. Because 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: 

Χത ൅ ሾ2.576 ൈ ݏ݁ሿ. For the data from Nortshore, this is: 110.0 ൅ ሾ2.576 ൈ 9.269ሿ. 

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 data from these units, the 

recommended limit for Furnace 12 is the same as that for Furnace 11, although completing the calculation shown above 

would result in a slightly lower value for Furnace 12. 

Draft December 2011
After reviewing stack test data provided by NSM, the MPCA has determined that an appropriate BART NOX 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 NOX performance testing, simultaneously measured from all five furnace stacks 

at each of the two furnaces for 30 hourly data points. 

Draft December 2011
Northshore Mining Company - Data for NOX BART Limit on Indurating Furnaces

Line 11 Furnace - Combined Stacks Line 12 Furnace - Combined Stacks

Descriptive Statistics

Date and Time

Total Emission 

Rate, lb/hr Date/Time

Total Emission 

Rate, lb/hr Date and Time

Total Emission Rate, 

lb/hr Date/Time

Total Emission 

Rate, lb/hr Furnace 11 2008 2009

5/15/08 0:00 104.2 07/27/09 19:00 91.8 4/22/08 20:00 118.2 07/29/09 10:00 94.4 Average Emissions, lbs/hour 111.1 94.0

5/15/08 1:00 103.1 07/27/09 20:00 87.8 4/22/08 21:00 125.1 07/29/09 11:00 91.4 Stdev 8.7 3.85/15/08 2:00 100.2 07/27/09 21:00 95.2 4/22/08 22:00 125.8 07/29/09 12:00 91.8 Count 176 35

5/15/08 3:00 110.0 07/27/09 22:00 95.9 4/22/08 23:00 126.7 07/29/09 13:00 92.1 Maximum lbs/hour 130.4 102.0

5/15/08 4:00 111.0 07/27/09 23:00 97.0 4/23/08 0:00 127.1 07/29/09 14:00 95.5 Minimum lbs/hour 73.5 87.85/15/08 5:00 110.2 07/28/09 00:00 100.0 4/23/08 1:00 128.0 07/29/09 15:00 89.9 t0.05, C-1 1.974 2.032

5/15/08 6:00 113.5 07/28/09 01:00 99.6 4/23/08 2:00 128.1 07/29/09 16:00 92.0 95% UPL 114.46 95.92

5/15/08 7:00 113.5 07/28/09 02:00 94.6 4/23/08 3:00 127.2 07/29/09 17:00 92.8 t0.01, c-1 2.604 2.728

5/15/08 8:00 113.1 07/28/09 04:00 4/23/08 4:00 126.9 07/29/09 18:00 90.5 99% UPL 115.97 93.85

5/15/08 9:00 100.6 07/28/09 05:00 90.8 4/23/08 5:00 128.3 07/29/09 19:00 90.3

5/15/08 10:00 116.4 07/28/09 06:00 92.2 4/23/08 6:00 130.1 07/29/09 20:00 94.0

5/15/08 11:00 117.2 07/28/09 07:00 90.4 4/23/08 7:00 129.4 07/29/09 21:00 89.5 Furnace 12 2008 2009

5/15/08 12:00 113.2 07/28/09 08:00 95.2 4/23/08 8:00 119.4 07/29/09 22:00 91.0 Average Emissions, lbs/hour 98.9 90.1

5/15/08 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 89.4 t0.05, C-1 1.975 2.040

5/15/08 18:00 104.6 07/28/09 14:00 89.7 4/23/08 14:00 102.2 07/30/09 04:00 90.0 95% UPL 114.49 91.405/15/08 19:00 105.5 07/28/09 15:00 93.1 4/23/08 15:00 98.1 07/30/09 05:00 90.2 t0.01, c-1 2.608 2.7445/15/08 20:00 108.8 07/28/09 16:00 90.0 4/23/08 16:00 96.3 07/30/09 06:00 88.9 99% UPL 115.86 87.62

5/15/08 21:00 106.9 07/28/09 17:00 89.8 4/23/08 17:00 92.8 07/30/09 07:00 86.3

5/15/08 22:00 110.6 07/28/09 18:00 88.1 4/23/08 18:00 91.9 07/30/09 08:00 90.0

5/15/08 23:00 103.0 07/28/09 19:00 91.3 4/23/08 19:00 95.0 07/30/09 09:00 91.0 All Data Combined

5/16/08 0:00 94.8 07/28/09 20:00 93.2 4/23/08 20:00 98.1 07/30/09 10:00 89.3 Average Emissions, lbs/hour 103.1

5/16/08 1:00 96.4 07/28/09 21:00 89.3 4/23/08 21:00 96.8 07/30/09 11:00 87.8 Stdev 11.5

5/16/08 2:00 97.2 07/28/09 22:00 90.5 4/23/08 22:00 93.8 07/30/09 12:00 85.7 Count 401

5/16/08 3:00 98.3 07/28/09 23:00 91.7 4/23/08 23:00 96.4 07/30/09 13:00 89.7 Maximum lbs/hour 130.4

5/16/08 4:00 108.8 07/29/09 00:00 93.6 4/24/08 0:00 94.6 07/30/09 14:00 88.4 Minimum lbs/hour 73.5

5/16/08 5:00 109.9 07/29/09 01:00 94.0 4/24/08 1:00 93.4 07/30/09 15:00 85.8 t0.05, C-1

5/16/08 6:00 113.2 07/29/09 02:00 98.6 4/24/08 2:00 92.8 07/30/09 16:00 87.3

/ / / / / / / /

2008 Stack Testing 2009 Stack Testing 2008 Stack Testing 2009 Stack Testing

5/16/08 7:00 101.6 07/29/09 03:00 102.0 4/24/08 3:00 92.3 07/30/09 17:00 85.4

5/16/08 8:00 98.7 07/29/09 04:00 97.3 4/24/08 4:00 92.3

5/16/08 9:00 101.3 07/29/09 05:00 98.6 4/24/08 5:00 92.9

5/16/08 10:00 103.2 07/29/09 06:00 101.4 4/24/08 6:00 91.35/16/08 11:00 99.2 95.5 4/24/08 7:00 87.6

5/16/08 12:00 99.6 4/24/08 8:00 91.7

5/16/08 13:00 106.7 4/24/08 9:00 90.2

5/16/08 14:00 106.9 4/24/08 10:00 89.65/16/08 15:00 109.5 4/24/08 11:00 89.85/16/08 16:00 110.3 4/24/08 12:00 88.15/16/08 17:00 111.2 4/24/08 13:00 93.05/16/08 18:00 115.5 4/24/08 14:00 90.65/16/08 19:00 113.4 4/24/08 15:00 89.95/16/08 20:00 118.1 4/24/08 16:00 93.65/16/08 21:00 124.2 4/24/08 17:00 93.75/16/08 22:00 118.0 4/24/08 18:00 92.95/16/08 23:00 125.2 4/24/08 19:00 88.7

5/17/08 0:00 129.5 4/24/08 20:00 88.4

5/17/08 1:00 130.4 4/24/08 21:00 89.5

5/17/08 2:00 129.7 4/24/08 22:00 88.5

5/17/08 3:00 129.2 4/24/08 23:00 91.2

5/17/08 4:00 123.4 4/25/08 0:00 91.2

5/17/08 5:00 119.9 4/25/08 1:00 92.9

5/17/08 6:00 116.6 4/25/08 2:00 95.3

5/17/08 7:00 112.0 4/25/08 3:00 93.2

5/17/08 8:00 112.0 4/25/08 4:00 91.3

5/17/08 9:00 110.2 4/25/08 5:00 88.3

5/17/08 10:00 108.7 4/25/08 6:00 93.7

Draft 
5/17/08 11:00 108.6 4/25/08 7:00 92.4

5/17/08 12:00 110.9 4/25/08 8:00 93.2

5/17/08 13:00 108.7 4/25/08 9:00 94.1

5/17/08 14:00 104.5 4/25/08 10:00 90.05/17/08 15:00 104.1 4/25/08 11:00 87.85/17/08 16:00 100.1 4/25/08 12:00 88.75/17/08 17:00 101.1 4/25/08 13:00 89.95/17/08 18:00 103.0 4/25/08 14:00 88.55/17/08 19:00 106.0 4/25/08 15:00 88.15/17/08 20:00 106.5 4/25/08 16:00 89.75/17/08 21:00 105.7 4/25/08 17:00 88.55/17/08 22:00 107.4 4/25/08 18:00 89.75/17/08 23:00 103.6 4/25/08 19:00 89.6

5/18/08 0:00 103.3 4/25/08 20:00 89.3

5/18/08 1:00 103.5 4/25/08 21:00 89.2

5/18/08 2:00 103.8 4/25/08 22:00 87.6

5/18/08 3:00 103.3 4/25/08 23:00 87.8

5/18/08 4:00 105.9 4/26/08 0:00 88.2

5/18/08 5:00 114.3 4/26/08 1:00 91.9

5/18/08 6:00 112.6 4/26/08 2:00 89.9

5/18/08 7:00 97.5 4/26/08 3:00 90.3

5/18/08 8:00 98.2 4/26/08 4:00 92.7

5/18/08 9:00 108.0 4/26/08 5:00 92.4

5/18/08 10:00 107.1 4/26/08 6:00 90.6

5/18/08 11:00 106.8 4/26/08 7:00 89.9

5/18/08 12:00 107.7 4/26/08 8:00 91.75/18/08 13:00 110.8 4/26/08 9:00 93.8

5/18/08 14:00 110.2 4/26/08 10:00 94.55/18/08 15:00 106.3 4/26/08 11:00 92.55/18/08 16:00 110.3 4/26/08 12:00 91.05/18/08 17:00 113.1 4/26/08 13:00 91.25/18/08 18:00 117.9 4/26/08 14:00 97.95/18/08 19:00 118.3 4/26/08 15:00 98.95/18/08 20:00 120.5 4/26/08 16:00 98.75/18/08 21:00 120.2 4/26/08 17:00 99.75/18/08 22:00 111.6 4/26/08 18:00 99.85/18/08 23:00 107.9 4/26/08 19:00 100.8

5/19/08 0:00 107.2 /19/08 0 00 10 2 4/26/08 20 00 4/26/08 20:00 100.5

5/19/08 1:00 106.1 4/26/08 21:00 101.9

5/19/08 2:00 111.9 4/26/08 22:00 103.5

5/19/08 3:00 109.4 4/26/08 23:00 105.4

5/19/08 4:00 112.2 4/27/08 0:00 104.3

5/19/08 5:00 116.9 4/27/08 1:00 104.35/19/08 6:00 107.6 4/27/08 2:00 105.05/19/08 7:00 102.1 4/27/08 3:00 104.75/19/08 8:00 104.2 4/27/08 4:00 102.55/19/08 9:00 106.5 4/27/08 5:00 103.2

5/19/08 10:00 110.0 4/27/08 6:00 102.3

5/19/08 11:00 110.7 4/27/08 7:00 98.0

5/19/08 12:00 112.3 4/27/08 8:00 98.2

5/19/08 13:00 115.3 4/27/08 9:00 97.3

5/19/08 14:00 126.2 4/27/08 10:00 98.35/19/08 15:00 126.7 4/27/08 11:00 96.65/19/08 16:00 126.4 4/27/08 12:00 97.45/19/08 17:00 125.7 4/27/08 13:00 99.65/19/08 18:00 125.5 4/27/08 14:00 98.95/19/08 19:00 126.7 4/27/08 15:00 99.45/19/08 20:00 129.3 4/27/08 16:00 99.35/19/08 21:00 128.0 4/27/08 17:00 98.65/19/08 22:00 117.6 4/27/08 18:00 98.65/19/08 23:00 120.5 4/27/08 19:00 99.1

5/20/08 0:00 121.6 4/27/08 20:00 100.0

5/20/08 1:00 120.0 4/27/08 21:00 102.2

5/20/08 2:00 118.7 4/27/08 22:00 106.1

5/20/08 3:00 119.8 4/27/08 23:00 105.4

Draft 
5/20/08 4:00 118.0 4/28/08 0:00 107.0

5/20/08 5:00 120.8 4/28/08 1:00 106.75/20/08 6:00 114.5 4/28/08 2:00 106.85/20/08 7:00 73.6 4/28/08 3:00 106.35/20/08 8:00 96.1 4/28/08 4:00 106.75/20/08 9:00 94.7 4/28/08 5:00 104.1

5/20/08 10:00 90.6 4/28/08 6:00 103.7

5/20/08 11:00 102.7 4/28/08 7:00 103.2

5/20/08 12:00 102.1 4/28/08 8:00 100.8

5/20/08 13:00 103.9 4/28/08 9:00 100.8

5/20/08 14:00 104.4 4/28/08 10:00 101.5

5/20/08 15:00 104.8 4/28/08 11:00 99.45/20/08 16:00 105.6 4/28/08 12:00 100.1

5/20/08 17:00 105.5 4/28/08 13:00 103.0

5/20/08 18:00 107.9 4/28/08 14:00 101.7

5/20/08 19:00 105.9 4/28/08 15:00 102.1

5/20/08 20:00 104.9 4/28/08 16:00 100.2

5/20/08 21:00 107.2 4/28/08 17:00 101.0

5/20/08 22:00 107.0 4/28/08 18:00 99.25/20/08 23:00 109.6 4/28/08 19:00 99.1

5/21/08 0:00 113.0 4/28/08 20:00 99.3

5/21/08 1:00 120.6 4/28/08 21:00 98.8

5/21/08 2:00 120.6 4/28/08 22:00 98.0

5/21/08 3:00 122.5 4/28/08 23:00 100.4

5/21/08 4:00 118.4 4/29/08 0:00 71.8

5/21/08 5:00 117.8 4/29/08 1:00 3.15/21/08 6:00 121.2 4/29/08 2:00 45.6

5/21/08 7:00 123.9 4/29/08 3:00 85.9

5/21/08 8:00 116.4 4/29/08 4:00 97.8

5/21/08 9:00 119.0 4/29/08 5:00 97.0

5/21/08 10:00 119.9 4/29/08 6:00 96.6

5/21/08 11:00 117.7 4/29/08 7:00 98.95/21/08 12:00 119.9 4/29/08 8:00 96.5

5/21/08 13:00 118.8 4/29/08 9:00 96.3

5/21/08 14:00 118.5 4/29/08 10:00 93.25/21/08 15:00 120.7 4/29/08 11:00 90.95/21/08 16:00 123.5 4/29/08 12:00 88.5

5/21/08 17:00 121.4 /21/08 1 00 121 4 4/29/08 13 00 4/29/08 13:00 89 2.5/21/08 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 99.1

5/22/08 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

Draft 
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

Draft December 2011
> 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] 1.616225

Draft December 2011
Histogram of Bootstrap Distribution (Excel, se = 1.563)

Histogram of Bootstrap Distribution (R, se = 1.612)

Draft December 2011
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 1.960 102.6

Draft December 2011
Histogram of Bootstrap Distribution (Excel, se = 1.883)

Histogram of Bootstrap Distribution (R, se = 1.896)

Draft December 2011
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 Environmental 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 NOX 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 taconite 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 pellets. 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, Line 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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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. 

Draft December 2011
The MPCA is required to determine BART for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions 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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 NOX 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 primary fuel. Since natural gas is low in sulfur, the primary 

source of sulfur at the Line 1 furnace was the iron ore used 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 SO2 BART determination 

for Line 1 was current operation of the wet scrubbers, with a corresponding emission limit of 0.121 lbs SO2/long ton of 

pellets produced. 

The Line 2 indurating furnace is permitted to burn pulverized coal, a coal/pet coke blend, distillate oil, and natural gas. It 

is primarily operated using a blend of coal and pet coke. Therefore, 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 SO2 BART determination for Line 2 

was for fuel blending to reduce SO2 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 NOX BART determination for Line 1 is good combustion practices and implementation of a past heat 

recuperation project. The MPCA’s NOX 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 NOX 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. 

 

Draft December 2011
2.4 MPCA Determination of the “Baseline” BART Limit

Setting the BART limits for United Taconite is a two-step process, because of a planned change in facility operations. The 

MPCA was unable to find guidance on how to evaluate appropriate 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 NOX

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 NOX emissions from the two lines at UTac does not fit any standard statistical probably 

curve. Therefore, the calculation to set the emission limit 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 prediction level was used to develop the BART limit. The upper 

prediction level was used, rather than the upper confidence level, 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 available, means that the available data likely does not demonstrate the entire range of 

data. Because of these limitations of the data, the upper prediction level is more appropriate to use, and creates a limit 

that is slightly above the maximum emissions level shown in the available data. (A 99% confidence interval was used for 

Line 2 in order to ensure that the upper prediction level is above the maximum demonstrated emissions level.) 

UTac NOX Emissions Descriptive Statistics 

(30 day rolling average, lbs/hour)

 Line 1 NOX Line 2 NOX 

(Stack A) 

Line 2 NOX 

(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 NOX 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 

SO2 BART Limit 0.121 lbs/LT pellet 1.7 lbs/MMBtu 

NOX BART Limit 1018.3 lbs/hour 753.8 lbs/hour 

 

Draft December 2011
2.5 Facility Changes and the BART Limit

In August 2010, after the MPCA determined the BART work practices and controls for 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 from the MPCA, UTac must submit to the MPCA a permit 

application to incorporate into its air emission permit either 1) NOX and SO2 BART emission limits as described in this 

memo or 2) a BART alternative as described 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) 

SO2 Limit 106.3 tons as a 30-day rolling sum 197 tons as a 30-day rolling sum 

NOX 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 table shows the MPCA’s calculation of annual 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 Capacity1

Line 1 Line 2 Total 

 NOX SO2 NOX SO2 NOX SO2

Past Emissions2 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 proposal is essentially unconstraining, except for the SO2 emissions 

limit for Line 2. Compared to past actual emissions, the MPCA’s baseline BART proposal results in about a 2500 tons per 

year decrease in overall emissions of NOX and SO2. The proposal by UTac results in a 4350 tons per year decrease in 

overall emissions as compared to the past emission scenario, 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 emissions and MPCA proposals were done using the maximum furnace throughput and 

assuming 8760 hours of operation annually. 

2

 Because the facility does not have NOX emission limits, the past emissions for NOX were estimated using baseline actuals from the 

August 2010 permitting action. Line 1 SO2 unlimited emissions were estimated the same way, while Line 2 SO2 unlimited emissions 

were estimated using the statewide 4.0 lbs/MMBtu emission limit, which is higher than the baseline actuals of 3652 tpy. 

Draft December 2011
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 Capacity3

Line 1 Line 2 

 NOX SO2 NOX SO2

Past Emissions4 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 SO2 limit on Line 1 to account for the addition of solid fuels, it results in lower NOX limits 

on both lines and lower SO2 limits on Line 2 than the MPCA’s baseline BART proposal. This, combined with the total 

annual emissions decrease, leads the MPCA to determine the following limits are BART for United Taconite. 

Unit BART NOX Limit

(tons per day, 30-day rolling average) 

BART SO2 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 were done using the maximum furnace throughput and assuming 

8760 hours of operation annually. The unlimited emissions also include the baseline 

4

 Because the facility does not have NOX emission limits, the unlimited emissions for NOX were estimated using baseline actuals from 

the August 2010 permitting action. Line 1 SO2 unlimited emissions were estimated the same way, while Line 2 SO2 unlimited 

emissions were estimated using the statewide 4.0 lbs/MMBtu emission limit, which is higher than the baseline actuals of 3652 tpy. 

Draft December 2011
Line 1

Furnace Capacity 280 tons pellets/hour 190 MMBtu/hr 2,452,800 tons pellets/yearProposed Operations (From 8/10 Permit) 250 tons pellets/hour 0.61 MMBtu/LT pellets 1,950,000 tons pellets/year 1,189,500 MMBtu/year

Past Emissions Estimate - L1 on Natural Gas - Full Furnace Capacity lbs/hour lbs/day tons per day tons per year

NOX 3.5639 lbs/long tons pellet 997.892 23949.41 11.97 4371 Estimated using baseline Actuals from 8SO2 0.0308 lbs/long tons pellet 8.624 206.98 0.10 38 Estimated using baseline Actuals from 8

Past Emissions Estimate - L1 on Natural Gas - Proposed OperationsNOX 3.5639 lbs/long tons pellet 890.975 21383.40 10.69 3475SO2 0.0308 lbs/long tons pellet 7.7 184.80 0.09 30

Potential Emissions Estimate - L1 on Solid Fuels - Full Furnace CapacityNOX 0.6685 lbs/long tons pellet 187.18 4492.32 2.25 820 Baseline Actual emission factor from Lin

SO2 4.0 lbs/MMBtu 760 18240.00 9.12 3329 Using statewide 4.0 emission factor

Potential Emissions Estimate - L1 on Solid Fuels - Proposed OperationsNOX 0.6685 lbs/long tons pellet 167.125 4011.00 2.01 652 Baseline Actuals emission factor for Lin

SO2 4.0 lbs/MMBtu 610 14640.00 7.32 2379 Using statewide 4.0 emission factor

MPCA Limit - L1 on Natural Gas - Full Furnace CapacityNOX 1018.3 lbs/hour 1018.3 24439.2 12.22 4460

SO2 0.121 lbs/long tons pellet 33.88 813.12 0.41 148

MPCA Limit - Proposed OperationsNOX 1018.3 lbs/hour 3971 7800 hours of operation annua

SO2 0.121 lbs/long tons pellet 118

Utac Proposed Limit - Full Furnace CapacityNOX 816 tons/180 days 4.53 1655SO2 106.3 tons/30 days 3.54 1293

1.7 lbs/MMBtu 323 7752 3.88 1415 Sample calculation, based on baseline S

Line 2Furnace Capacity 672 tons pellets/hour 400 MMBtu/hr

Proposed Operations 4,050,000 tons pellets/year 0.52 MMBtu/LT 2,106,000 MMBtu/year

Past Emissions Estimate - Full Furnace Capacity lbs/hour lbs/day tons per day tons per year

NOX 0.6685 lbs/long tons pellets 449.232 10781.568 5.39 1968 Estimated using baseline Actuals from LSO2 4.0 lbs/MMBtu 1600 38400 19.20 7008 Using 4.0 emission factor; baseline actu

Past Emissions Estimate - Proposed OperationsNOX 0.6685 lbs/long tons pellets 1354 Estimated using baseline Actuals from L

SO2 4.0 lbs/MMBtu 4212 Using 4.0 emission factor; baseline actu

MPCA Limit - Full Furnace CapacityNOX 753.8 lbs/hour 753.8 18091.2 9.05 3302SO2 1.7 lbs/MMBtu 680.0 16320 8.16 2978MPCA Limit - Proposed OperationsNOX 753.8 lbs/hour 2271 6027 hours of operation annua

SO2 1.7 lbs/MMBtu 1790

Draft 
Utac Proposed Limit tons per day tons per year

NOX 1820 tons/180 days 10.11 3692

SO2 197 tons/30 day 6.57 2394

Reported Actual Emissions from UTac 2007 2008 2009NOX 4263 3540 1968

SO2 3654 3726 2936

Total Emissions - Full Furnace Capacity NOX SO2

Past and Unmodified 6338 7046

MPCA BART 7762 3127

MPCA - Past 1423 -3919 -2496Utac BART 5347 3687

Utac BART - Past -991 -3359 -4350

Utac BART - MPCA -2415 560 -1855

Total Emissions - Proposed Operations NOX SO2

Past and Unmodified 4829 4242 Using baseline actuals and proposed future annual throughput.

MPCA BART 6243 1908 Using proposed annual throughput.

MPCA - Past 1414 -2334 -920Utac BART 5347 3687

Utac BART - Past 518 -555 -37

Utac BART - MPCA -896 1779 883

Draft 
DEPARTMENT: 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 Environmental 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 NOX and SO2 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 

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 processing facility in Keewatin, Minnesota, known as Keetac. At 

Keetac, U.S. Steel operates one grate-kiln furnace (the “Phase II furnace;” EU030) constructed 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 natural gas, distillate fuel oils, coal, and petroleum coke in 

the 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 green balls, although this represents a smaller 

contribution than the sulfur in the solid fuels burned. Sulfur 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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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 for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated achievable emission limits. The analysis must take into 

Draft December 2011
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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 emission limits consistent with that determination 

are: 

Emission Unit Name EU Number1

 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 Appendix 9.3 of the December 2009 Regional Haze SIP 

submittal. 

The NOX 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 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 for the indurating 

furnaces. Instead, the MPCA and Keetac entered into an Administrative Order, under which Keetac agreed to install and 

maintain Continuous Emissions Monitoring Systems (CEMS) and provide NOX emission information to the MPCA. 

The SO2 BART determination is operation of the existing wet scrubber. However, as with NOX, additional emission 

information was needed prior to setting an SO2 limit from this primarily coal-fired furnace. Keetac agreed in an 

Administrative Order to install and maintain SO2 CEMS and provide emission information to the MPCA. 

2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NOX and SO2 emission information provided by Keetac. 

NOX emission data was received going back to November 2008, but the Keetac facility 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 March 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 Unit (EU), Control Equipment (CE), 

and Stack/Vent (SV) numbers. 

Draft December 2011
 

Frequency of NOX Emissions (tpd) NOX Emissions Over Time (tpd) 

Frequency of SO2 Emissions (tpd) SO2 Emissions Over Time (tpd) 

Draft December 2011
The following table shows descriptive statistics of the NOX and SO2 emissions from the furnace, in tons per day. 

Keetac Emissions Descriptive Statistics 

(30 day rolling average, tons per day)

 Furnace NOX Furnace SO2

# 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 has determined that the appropriate BART limits are those 

shown in the following table. 

Keetac BART Limits 

(30 day rolling average, tons per day)

 Furnace NOX Furnace SO2

BART Limit 12.35 2.71 

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

Draft December 2011
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/hr

Limit/Max 99% 103%

1029 225.8 uniform limit, lb/hr

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

SO2

Draft December 2011
All rows of data:

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

Draft December 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 Settings\\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)

Draft December 2011
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 1.96

Draft December 2011
1/20/10 439 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 1.94

Draft December 2011
3/16/10 494 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 1.14

Draft December 2011
5/10/10 549 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 2.06

Draft December 2011
7/4/10 604 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 1.91

Draft December 2011
8/28/10 659 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 1.07

Draft December 2011
10/22/10 714 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 1.20

Draft December 2011
12/16/10 769 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 0.58

Draft December 2011
2/9/11 824 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 0.50

Draft December 2011
DEPARTMENT: 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 Environmental Data Management Section 

Environmental Analysis and Outcomes Division 

 

PHONE: 651-757-2467 651-757-2607 

SUBJECT: Nitrogen Oxides BART Limits for U.S. Steel – Minnesota Ore Operations (Minntac)

This memo was prepared to provide the documentation of the MPCA’s NOX and SO2 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 

U.S. Steel Corp. Minnesota Ore Operations 

P.O. Box 417 

Mountain Iron, MN 55768 

Minntac 

County Highway 102 

Mountain Iron; St. Louis County 

Contact: Ms. Chrissy Bartovich; 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 NOX BART limit for these five lines, along with the SO2 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 older 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 older sources that contribute to visibility impairment in Class I Areas to install Best 

Available Retrofit Technology (BART). On July 6, 2005, U.S. EPA published 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 for each source subject to BART based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions achievable. The analysis must take 

into consideration the technology available, the costs of compliance, the energy and non-air quality environmental 

Draft December 2011
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 anticipated to result from use of the technology. 

Further discussion of the regulatory basis for this determination 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 emission limits consistent with that determination 

are: 

Emission Unit Name EU Number1

 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 documented in Appendix 9.3 of the December 2009 Regional Haze 

SIP submittal. 

The NOX BART determination for the five indurating furnaces is generally good combustion practices. This is coupled 

with low-NOX burners in the pre-heat zone and fuel blending for Lines 4, 5, 6, and 7. Low NOX 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 representing the range of operating conditions that influence 

emissions, the MPCA did not set a NOX 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 NOX emission information 

to the MPCA. 

The SO2 BART determination for the indurating furnaces is operation of existing controls. In the initial Regional Haze SIP, 

the MPCA set a corresponding SO2 emission limit for Lines 3, 4, and 5, as these lines are natural gas and biomass fired 

and the SO2 emissions come primarily from the ore. However, as with NOX, additional emission information was needed 

prior to setting an SO2 limit from the coal-fired Lines 6 and 7. Minntac agreed in an Administrative Order to install and 

maintain SO2 CEMS on these lines and provide emission information to the MPCA. In addition, Minntac has installed SO2

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 SO2 on Line 3, 4, and 5. 

 

 

1

 The MPCA organizes conditions and illustrates associations in its permits using the Emission Unit (EU), Control Equipment (CE), 

and Stack/Vent (SV) numbers. 

Draft December 2011
2.4 MPCA Determination of the BART Limit

The MPCA reviewed the NOX and SO2 emission information from all five indurating furnaces provided by Minntac. 

NOX emission data was received beginning in October 2007 and SO2 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 NOX emissions recorded through the spring and summer months 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. SO2 emissions were then looked at over the same time frame. 

The following graph shows the variation in NOX emissions over the analyzed time frame. 

The following table shows descriptive statistics of the NOX emissions for each line, in tons per day. 

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

 Line 3 NOX Line 4 NOX Line 5 NOX Line 6 NOX Line 7 NOX

# 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

Draft December 2011
The following graphs show the variation in SO2 emissions for all lines over the analyzed time frame. 

The following table shows descriptive statistics of the SO2 emissions for Lines 6 and 7, in tons per day 

Minntac SO2 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 appropriate 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 NOX limits are 

Line NOX 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

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

L3 SO2

L4 SO2

L5 SO2

L6 SO2

L7 SO2

Draft December 2011
And the appropriate BART SO2 Limits are: 

Line SO2 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. Compliance is to be determined through continued operation of 

the CEMS. 

 

Draft December 2011
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

Draft December 2011
Supporting Plots 

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

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

 

Draft December 2011
NOX Recent Data - L5: 9/29/2009-3/31/2011 

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

 

Draft December 2011
NOX Recent Data - L7: 8/22/2009-3/31/2011 

SO2 Recent Data – L3 

- 

 

Draft December 2011
SO2 Recent Data – L6 

SO2 Recent Data – L7 

 

Draft December 2011
Supporting Derived Values 

Draft December 2011
Draft December 2011
Appendix 2: BART Administrative Orders 

 

Draft December 2011
-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) pursuant to Minn. Stat. § 116.07, subd. 9 (2011). 

FINDINGS OF FACT 

BACKGROUND

1. On July 6, 2005, the U.S. Environmental Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants contributing to regional haze are particulate matter (PM), sulfur 

dioxide (SO2), and nitrogen oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-DRAFT2 

6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submittal 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 Virginia, Minnesota. Arcelor makes fully fluxed pellets 

using one straight grate indurating furnace. The 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 indurating 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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

11. The Facility includes units that are subject to BART. See RESULTS of Best Available Retrofit 

Technology (BART) Modeling to Determine Sources 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-BART and for which Arcelor performed a BART analysis. This 

Draft December 2011
-DRAFT3 

unit has four stack vents. The stack vents associated with the unit are SV014, SV015, SV016, and 

SV017. 

13. MPCA determined and Arcelor agreed 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 SO2 emissions; and 

b. Good combustion practices and operation of low NOX burners in the pre-heat zone to 

control NOX 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 emission limits in an enforceable document. [40 CFR § 51.302 (c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue 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 long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 SO2 [40 CFR § 

50.17] and nitrogen dioxide (NO2) [40 CFR § 50.11]. As a result, Arcelor must model compliance with 

the one-hour and SO2 and NO2 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 Limitations and Compliance Methods 

a. BART for NOX

Draft December 2011
-DRAFT4 

i. Emission Limitations 

1. NOX emissions from EU026 shall not exceed 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 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. 

3. The NOX 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 NOX emission limit above as 

follows: 

1. NOX stack testing, with simultaneous 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 NOX performance test. Within 12 months of the date 

that the emissions limit becomes effective, Arcelor shall conduct a 

performance test to demonstrate compliance with the BART limit 

for NOX emissions. 

b. Annual BART NOX performance tests. Each calendar year after the 

initial test, Arcelor shall conduct a performance test to 

demonstrate compliance with the BART limit for NOx emissions. The 

performance test shall be conducted annually within two months of 

the anniversary date of the initial BART NOx 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 SO2 

i. Emission Limitations 

1. SO2 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. 

Draft December 2011
-DRAFT5 

2. Hours during which EU026 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. 

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

4. The SO2 emission limit is effective on and after the date six months after 

the effective date of EPA’s approval of this BART determination. 

ii. Arcelor must demonstrate compliance with the SO2 emission limit above as follows: 

1. SO2 stack testing, with simultaneous 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 SO2 performance test. Within 12 months of the date 

that the emissions limit becomes effective, Arcelor shall conduct a 

performance test to demonstrate compliance with the BART limit 

for SO2 emissions. 

b. Annual BART SO2 performance tests. Each calendar year after the 

initial test, Arcelor shall conduct a performance test to 

demonstrate compliance with the BART limit for SO2 emissions. 

Each performance test shall be conducted annually within two 

months of the anniversary date of the initial BART SO2 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 parametric monitoring system (CPMS) 

to measure and record 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. 

Draft December 2011
-DRAFT6 

i. Arcelor shall not use data recorded during monitor 

malfunctions, associated repairs, and required quality 

assurance or control activities 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 emissions 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 permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

1. Information on NOX, SO2, and PM emission limits and operational 

requirements imposed by this Order. These records include this Order. 

Draft December 2011
-DRAFT7 

ii. Non Permanent Records: Arcelor 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 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 information 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 SO2 and NO2 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 Arcelor facility for NO2

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 modeled compliance with the one-hour SO2 

NAAQS (40 CFR 50.17) and one-hour NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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 change 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. 

Draft December 2011
-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

Draft December 2011
-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 Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants are particulate matter (PM), sulfur dioxide (SO2), and nitrogen 

oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-DRAFT2 

6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submittal 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, Cliffs Natural Resources, 

and US Steel; Cliffs Natural Resources is the managing agent. HTC operates three functionally 

equivalent straight grate indurating furnaces, which 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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

11. The Facility includes units that are subject to BART. See RESULTS of Best Available Retrofit 

Technology (BART) Modeling to Determine Sources 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 Emission Units 020, 021 and 022 in Air 

Emissions Permit No. 13700061-004, that are subject-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 stack vents associated with EU021, the Line 2 

Draft December 2011
-DRAFT3 

pelletizing furnace, are SV025, SV026, SV027, and SV028. The stack vents associated with EU022, the 

Line 3 pelletizing furnace, are SV029, SV030, SV031, and SV032. 

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

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

a. Operation of the existing wet scrubber to control SO2 emissions; and 

b. Good combustion practices to control NOX 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 emission limits in an enforceable document. [40 CFR § 51.302 (c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue this Administrative Order as the enforceable 

document by which to establish the BART emission limit for HTC. 

LONG-TERM STRATEGY

16. In the SIP, the MPCA established, as part of the long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 demonstration that their facilities are in attainment 

with the one-hour National Ambient Air Quality Standards (NAAQS) for SO2 [40 CFR § 50.17] and 

nitrogen dioxide (NO2) [40 CFR § 50.11]. As a result, HTC must model compliance with the one-hour 

and SO2 and NO2 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 Limitations and Compliance Methods 

a. BART for Nitrogen Oxides (NOX) 

Draft December 2011
-DRAFT4 

i. Emission Limitations 

1. NOX emissions from Line 1, EU020, shall not exceed 447.4 lbs/hour at all 

times that EU020 is operating, measured on a 30-day rolling average; 

2. NOX emissions from Line 2, EU021, shall not exceed 571.7 lbs/hour at all 

times that EU021 is operating, measured on a 30-day rolling average; 

3. NOX emissions from Line 3, EU022, shall not exceed 338.3 lbs/hour at all 

times that EU022 is operating, measured 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 NOX 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 NOX emission limits above as follows: 

1. NOX stack testing with simultaneous 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 NOX 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 NOX

emissions. 

b. Annual BART NOX performance tests. Each calendar year after the 

initial test, HTC shall conduct a performance test to demonstrate 

compliance with the BART limit for NOx emissions. The performance 

test shall be conducted between 10 months and 14 months after 

the previous BART NOx 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 required 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 (SO2) 

 

Draft December 2011
-DRAFT5 

i. Emission Limitations 

1. SO2 emissions from Line 1, EU020, shall not exceed 0.207 lbs SO2/long ton 

of pellets fired (finished) at all times that EU020 is operating, measured on 

a 30-day rolling average; 

2. SO2 emissions from Line 2, EU021, shall not exceed 0.207 lbs SO2/long ton 

of pellets fired (finished) at all times that EU021 is operating, measured on 

a 30-day rolling average; 

3. SO2 emissions from Line 3, EU022, shall not exceed 0.207 lbs SO2/long ton 

of pellets fired (finished) at all times 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 SO2 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 SO2 emission limits as follows: 

1. SO2 stack testing, with simultaneous 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 SO2 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 SO2 emissions. 

b. Annual BART SO2 performance tests. Each calendar year after the 

initial test, HTC shall conduct a performance test to demonstrate 

compliance with the BART limit for SO2 emissions. The performance 

test shall be conducted between 10 months and 14 months after 

the previous BART SO2 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. 

Draft December 2011
-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 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 parametric 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 activities in data averages and 

calculations used to report emission or operating levels, or 

to fulfill a minimum data availability 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 laid out in part 1, HTC may install and 

operate continuous emission monitoring 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 accordance 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. 

Draft December 2011
-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 SO2 and one NOX CEMS on the Line 2 

pelletizing furnace, EU021, measuring emissions from SV025, SV026, SV027, and SV028. The 

Plan shall provide that each CEMS is installed 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 requirements 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 NOX emissions limit shown in Part 1.a.i and SO2 emissions limit shown 

in Part I.b.i of this Order. 

III. Recordkeeping and Reporting 

a. Recordkeeping. HTC shall maintain electronic files 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 permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

1. Information on NOX, SO2, 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 information must be kept on site.

Draft December 2011
-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 modeling analyses and submit the following information in order to 

ensure expeditious attainment of the one-hour SO2 and NO2 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 NO2 emissions. 

The protocol must be submitted using MPCA’s most 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 modeled compliance with the one-hour SO2

and NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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 change 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. 

 

Draft December 2011
-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 

Draft December 2011
-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 Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants contributing to regional haze are particulate matter (PM), sulfur 

dioxide (SO2), and nitrogen oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-DRAFT2

6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submittal 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 located 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 the 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 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. 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 received a Prevention of Significant Deterioration 

permit authorizing the restarting of Furnace 5. 

9. NSM also operates two process boilers. 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. 

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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

Draft December 2011
-DRAFT3

13. The facility includes units that are subject to BART. See RESULTS of Best Available Retrofit 

Technology (BART) Modeling to Determine Sources 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 identified 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 NSM 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 process boiler #1, EU003, is SV003. The 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 (boiler #1 and boiler #2) are subject-to-BART. 

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

a. Operation of the existing wet scrubber to control SO2 emissions; 

b. Good combustion practices to control NOX emissions; and 

c. Implementation of the taconite Maximum Achievable 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 emission limits in an enforceable document. [40 CFR § 51.302(c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue this Administrative Order as the enforceable 

document by which to establish the BART emission limit for NSM. 

LONG-TERM STRATEGY

19. In the SIP, the MPCA established, as part of the long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 SO2 [40 CFR § 51.17] and 

nitrogen dioxide (NO2) [40 CFR § 51.11]. As a result, NSM must model compliance with the one-hour 

and SO2 and NO2 NAAQS. This Order establishes the tasks and schedules by which the modeling for 

NSM will be completed. 

Draft December 2011
-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 Limitations and Compliance Methods 

a. BART for NOX

i. Emission Limitations 

1. NOX emissions from Process Boiler #1 (EU003) shall not exceed 0.17 

lbs/hour at all times when EU003 is operating, measured on a 30-day rolling 

average. 

2. NOX emissions from Process Boiler #2 (EU004) shall not exceed 0.17 

lbs/hour at all times when EU004 is operating, measured on a 30-day rolling 

average. 

3. Hours during which the 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 NOX 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 NOX emission limits above will as 

follows: 

1. NOX stack testing, conducted in compliance with Minn. R. 7017.2001 

through Minn. R. 7017.2060. 

a. Initial BART NOX 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 NOX emissions. 

b. BART NOX performance tests. NSM shall conduct a performance 

test to demonstrate compliance with the BART limit for NOx

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. 

 

Draft December 2011
-DRAFT5

II. Furnace BART Emission Limitations and Compliance Methods 

a. BART for NOX

i. Emission Limitations 

1. NOX 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. NOX 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 NOX 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 NOX emission limits above as follows: 

1. NOX stack testing, with simultaneous 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 NOX 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 NOX

emissions. 

b. Annual BART NOX performance tests. Each calendar year after the 

initial test, NSM shall conduct a performance test to demonstrate 

compliance with the BART limit for NOx emissions. The performance 

test shall be conducted between 10 months and 14 months after 

the previous BART NOx 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 testing laid out in part 1, NSM 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. 

 

Draft December 2011
-DRAFT6

b. BART for Sulfur Dioxide (SO2) 

i. Emission Limitations 

1. SO2 emissions from Furnace 11 shall not exceed 0.0651 lbs SO2/long ton of 

pellets fired (finished), measured on a 30-day rolling average; 

2. SO2 emissions from Furnace 12 shall not exceed 0.0651 lbs SO2/long ton of 

pellets fired (finished), measured on a 30-day rolling average. 

3. This limit applies only when 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 SO2 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 SO2 emission limits above will be determined as follows: 

1. Annual SO2 stack testing, with simultaneous 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 SO2 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 SO2

emissions. 

b. Annual BART SO2 performance tests. Each calendar year after the 

initial test, NSM shall conduct a performance test to demonstrate 

compliance with the BART limit for SO2 emissions. The performance 

test shall be conducted between 10 months and 14 months after 

the previous BART SO2 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 subsequent performance test pursuant 

to an approved performance test plan, but must obtain MPCA 

authorization before implementing a proposed change. 

Draft December 2011
-DRAFT7

2. Operate and maintain a continuous parametric 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 activities 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 laid out in part 1, NSM 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 emissions from EU100 shall not exceed 0.01 

gr/dscf at all times when EU100 is operating; 

2. Filterable (front-half) PM emissions from EU104 shall not exceed 0.01 

gr/dscf at all times when EU104 is operating; 

3. Filterable (front-half) PM emissions from EU110 shall not exceed 0.01 

gr/dscf at all times when EU110 is operating; and 

4. Filterable (front-half) PM emissions 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. 

 

Draft December 2011
-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 permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

1. Information on NOX, SO2, 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 Facility requirements of NSM’s air emissions permit, pursuant 

to Minn. R. 7007.0800 and. NSM 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 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 SO2 and NO2 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 NO2

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 modeled compliance with the one-hour SO2

and NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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. 

Draft December 2011
-DRAFT9

General. 

24. Nothing in this Order shall relieve NSM of its obligation to meet permitting requirements for any 

physical or operational change 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 

Draft December 2011
-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 Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants contributing to regional haze are particulate matter (PM), sulfur 

dioxide (SO2), and nitrogen oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-DRAFT6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submittal 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 (herein referred to as “Facility”) located near Forbes, 

Minnesota. 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, Line 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. 

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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

11. The United facility includes two units (EU040 and EU042) that are subject to BART. See RESULTS of 

Best Available Retrofit Technology (BART) Modeling 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 pellet furnaces (EU040 and EU042) are subject-toBART. 

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

Draft December 2011
-DRAFTa. Operation of the existing wet scrubber and use of appropriate fuel blends to control SO2

emissions; 

b. Good combustion practices, along with existing combustion controls to control NOX

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 emission limits in an enforceable document. [40 CFR § 51.302(c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue this Administrative Order as the enforceable 

document by which to establish the BART emission limit for United. 

LONG-TERM STRATEGY

16. In the SIP, the MPCA established, as part of the long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 SO2 [40 CFR § 

50.17] and nitrogen dioxide (NO2) [ 40 CFR § 50.11]. As a result, United must model compliance with 

the one-hour and SO2 and NO2 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 control equipment or undertake any necessary work 

practices to meet the following requirements which represent BART for United. 

I. BART Emission Limitations and Compliance Methods 

a. BART for Nitrogen Oxides (NOX) 

i. Emission Limitations 

1. NOX 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. NOX 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. 

Draft December 2011
-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 NOX emission limit is effective on and after the date six months after 

the effective date of U.S. EPA’s approval of United’s BART determination. 

ii. Compliance with the NOX emission limit above will be demonstrated through the 

use of continuous emission monitoring systems (CEMS) in accordance with Minn. R. 

7017.1002 through Minn. R. 7017.1220. 

b. BART for Sulfur Dioxide (SO2) 

i. Emission Limitations 

1. SO2 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. SO2 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 SO2 emission limit is effective on and after the date six months after 

the effective date of U.S. EPA’s approval of United’s BART determination. 

ii. Compliance with the SO2 emission limit above will be determined through the use 

of continuous emission monitoring systems (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. 

Draft December 2011
-DRAFTII. Recordkeeping and Reporting 

a. Recordkeeping. United shall maintain 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 inspection and review. 

i. Permanent Records: United shall permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

1. Information on NOX, SO2, and PM emission limits and operational 

requirements imposed by this Order. These records include this Order. 

ii. Non Permanent Records: United 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 United’s air emissions 

permit, pursuant to Minn. R. 7007.0800. United 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 information 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 SO2 and NO2 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 United facility for NO2

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 modeled compliance with the one-hour SO2 

NAAQS and one-hour NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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. 

Draft December 2011
-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

Draft December 2011
-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 Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants contributing to regional haze are particulate matter (PM), sulfur 

dioxide (SO2), and nitrogen oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-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 submittal 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 Taconite, 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. EU068/EU069/EU070 are not yet operational. 

8. The permit allows Keetac to combust natural gas, distillate 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 contribution 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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

Draft December 2011
-DRAFT12. The Keetac facility includes one unit (EU030) that is subject to BART. See RESULTS of Best Available 

Retrofit Technology (BART) Modeling 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 SO2 emissions; and 

b. Good combustion practices, along with existing combustion controls and fuel blending to 

control NOX emissions; and 

c. Implementation of the taconite Maximum Achievable Control Technology (MACT) standard 

to control PM emissions. [40 CFR 63, Subp. RRRRR]. 

16. The MPCA must place BART emission limits in an enforceable document. [40 CFR § 51.302 (c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue this Administrative Order as the enforceable 

document by which to establish the BART emission limit for Keetac. 

LONG-TERM STRATEGY

17. In the SIP, the MPCA established, as part of the long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 SO2 [40 CFR § 

50.17] and nitrogen dioxide (NO2) [ 40 CFR § 50.11]. As a result, Keetac must model compliance with 

the one-hour and SO2 and NO2 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 requirements which represent BART for Keetac. 

Draft December 2011
-DRAFTI. BART Emission Limitations and Compliance Methods 

a. BART for Nitrogen Oxides (NOX) 

i. Emission Limitations 

1. NOX 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 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. 

3. The NOX emission limit is effective on and after the date six months after 

the effective date of U.S. EPA’s approval of Keetac’s BART determination. 

ii. Compliance with the NOX emission limit above will be demonstrated through the 

use of continuous emission monitoring systems (CEMS) in accordance with Minn. R. 

7017.1002 through Minn. R. 7017.1220. 

b. BART for Sulfur Dioxide (SO2) 

i. Emission Limitations 

1. SO2 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 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. 

3. The SO2 emission limit is effective on and after the date six months after 

the effective date of U.S. EPA’s approval of Keetac’s BART determination. 

ii. Compliance with the SO2 emission limit above will be determined through the use 

of continuous emission monitoring systems (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 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. 

Draft December 2011
-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 inspection and review. 

i. Permanent Records: Keetac shall permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

1. Information on NOX, SO2, and PM emission limits and operational 

requirements imposed by this Order. These records include this Order. 

ii. Non Permanent Records: Keetac 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 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 information 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 SO2 and NO2 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 modeled compliance with the one-hour SO2 

NAAQS and one-hour NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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. 

Draft December 2011
-DRAFTGeneral. 

22. Nothing in this Order shall relieve Keetac 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 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

Draft December 2011
-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 Protection Agency (U.S. EPA) published regulations to 

address visibility impairment in our nation’s largest national parks and wilderness (“Class I”) areas 

[70 Fed. Reg. 39103]. This rule is commonly known 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 that contribute to regional haze. The MPCA has 

determined that the key pollutants contributing to regional haze are particulate matter (PM), sulfur 

dioxide (SO2), and nitrogen oxides (NOX). 

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 establish, for each Class I area within the state, 

“goals (expressed in deciviews) that provide 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 Class I areas. States, including Minnesota, must 

determine what constitutes the best available retrofit technology (BART) to control for PM, 

SO2, and NOX 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 determinations, 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. 

Draft December 2011
-DRAFT6. On <December 19, 2011>, the MPCA put its proposed supplemental SIP submittal 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 Range north of the City of Mountain Iron, St. Louis 

County, Minnesota. 

8. 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. 

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 which 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 determination of BART. As required, the MPCA took 

into consideration the technology available, the costs of compliance, 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 source, 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 fit 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 August 7, 1977 and began operation at some point 

on or after August 7, 1962; and 

c. The sum of the potential emissions from all emission unit(s) identified in the previous two 

bullets was greater than 250 tons per year of the visibility-impairing pollutants: SO2, NOX, and 

PM. 

Draft December 2011
-DRAFT12. Minntac includes units that are subject to BART. See RESULTS of Best Available Retrofit Technology 

(BART) Modeling to Determine Sources Subject-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 stack vent associated with EU225, the 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 furnace, is SV127. The stack vent associated with 

EU315, the Line 6 indurating furnace, is SV144. The stack vent associated with EU334, the Line7 

indurating furnace, is SV151. 

14. MPCA determined and US Steel agreed that Minntac’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 SO2 emissions; and 

b. Good combustion practices and fuel blending to control NOX emissions for Lines 3, 4, 5, 6, 

and 7, with the addition of low-NOX burners in the pre-heat zone for Lines 4, 5, 6, and 7; and 

c. Implementation of the taconite Maximum Achievable Control Technology (MACT) standard 

to control PM emissions. 40 CFR 63, Subp. RRRRR. 

16. The MPCA must place BART emission limits in an enforceable document. [40 CFR § 51.302 (c)(3); 40 

CFR § 51.308(e)((1)(iv)]. The MPCA has chosen to issue 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 long-term strategy, a target or goal of a reduction in 

combined SO2 and NOX emissions from large point sources located in St. Louis, Lake, Cook, Carlton, 

Itasca and Koochiching counties that emitted over 100 tons per year of either SO2 or NOX 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 therefore 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 SO2 [40 CFR § 

50.17] and nitrogen dioxide (NO2) [40 CFR § 50.11]. As a result, Minntac must model compliance 

with the one-hour and SO2 and NO2 NAAQS. This Order establishes the tasks and schedules by which 

the modeling for Minntac will be completed. 

Draft December 2011
-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 requirements, which represent BART for Minntac. 

I. BART Emission Limitations and Compliance Methods 

a. BART for Nitrogen Oxides (NOX) 

i. Emission Limitations 

1. NOX 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. NOX 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. NOX 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. NOX 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. NOX 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 NOX 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 NOX emission limits above will be demonstrated through the 

use of continuous emission monitoring systems (CEMS) in accordance with Minn. R. 

7017.1002 through Minn. R. 7017.1220. 

b. BART for Sulfur Dioxide (SO2) 

i. Emission Limitations 

1. SO2 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; 

Draft December 2011
-DRAFT2. SO2 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. SO2 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. SO2 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. SO2 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 SO2 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 SO2 emission limits above will be determined through the use 

of continuous emission monitoring systems (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 inspection and review. 

i. Permanent Records: Minntac shall permanently maintain the following information 

together with all amendments, revisions, and modifications to this information. 

Draft December 2011
-DRAFT1. Information on NOX, SO2, 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 information 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 SO2 and NO2 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 modeled compliance with the one-hour SO2 

NAAQS and one-hour NO2 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 SO2 and NO2 NAAQS; 

iii. A description of the work practices or controls 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 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. 

Draft December 2011
-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

Draft December 2011
Appendix 3: Termination of Monitoring Orders 

Draft December 2011
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 Mine, 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 Commissioner’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”) regarding 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 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 the date of the signature of the Commissioner of the 

MPCA or the Commissioner’s representative below. 

Draft December 2011
BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE 

AUTHORITY TO AMEND THE ORIGINAL AGREMENT 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: ___________________________ 

Draft December 2011
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 Commissioner’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”) regarding 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 the date of the signature of the Commissioner of the 

MPCA or the Commissioner’s representative below. 

Draft December 2011
BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE 

AUTHORITY TO AMEND THE ORIGINAL AGREMENT 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: ___________________________ 

Draft December 2011
STATE OF MINNESOTA 

Minnesota Pollution Control Agency 

In the Matter of: AMENDMENT NO. 1 TO ADMINISTRATIVE 

Northshore Mining Company – Silver 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 Commissioner’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”) regarding 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 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 the date of the signature of the Commissioner of the 

MPCA or the Commissioner’s representative below. 

Draft December 2011
BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE 

AUTHORITY TO AMEND THE ORIGINAL AGREMENT 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: ___________________________ 

Draft December 2011
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 Commissioner’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”) regarding 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 the date of the signature of the Commissioner of the 

MPCA or the Commissioner’s representative below. 

Draft December 2011
BY THEIR SIGNATURES BELOW, THE UNDERSIGNED REPRESENT THAT THEY HAVE 

AUTHORITY TO AMEND THE ORIGINAL AGREMENT 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: ___________________________ 

Draft December 2011