[Federal Register Volume 81, Number 70 (Tuesday, April 12, 2016)]
[Rules and Regulations]
[Pages 21671-21697]
[FR Doc No: 2016-07818]

Vol. 81

Tuesday,

No. 70

April 12, 2016

Part II

Environmental Protection Agency

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40 CFR Part 52

Air Plan Approval; Minnesota and Michigan; Revision to 2013 Taconite
Federal Implementation Plan Establishing BART for Taconite Plants;
Final Rule

Federal Register / Vol. 81 , No. 70 / Tuesday, April 12, 2016 / Rules
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2015-0196; FRL-9944-22-Region 5]

Air Plan Approval; Minnesota and Michigan; Revision to 2013
Taconite Federal Implementation Plan Establishing BART for Taconite
Plants

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing a
revision to the Federal implementation plan (FIP) addressing the
requirement for best available retrofit technology (BART) for taconite
plants in Minnesota and Michigan. In response to petitions for
reconsideration, we are revising the nitrogen oxides (NOX)
limits for taconite furnaces at facilities owned and operated by Cliffs
Natural Resources (Cliffs) and ArcelorMittal USA LLC (ArcelorMittal).
Cliffs owns and operates Tilden Mining and United Taconite. Hibbing is
owned by Cliffs, ArcelorMittal and U.S. Steel and operated by Cliffs.
ArcelorMittal is owner and operator of Minorca Mine. We are also
revising the sulfur dioxide (SO2) requirements at two of
Cliffs' facilities. We are making these changes because new information
has come to light that was not available when we originally promulgated
the FIP on February 6, 2013.

DATES: This final rule is effective on May 12, 2016.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-R05-OAR-2015-0196. All documents in the docket are listed in
the www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either in
www.regulations.gov or at the Environmental Protection Agency, Region
5, Air and Radiation Division, 77 West Jackson Boulevard, Chicago,
Illinois 60604. This facility is open from 8:30 a.m. to 4:30 p.m.,
Monday through Friday, excluding Federal holidays. We recommend that
you telephone Steven Rosenthal at<PHONE_NUMBER> before visiting the
Region 5 office.

FOR FURTHER INFORMATION CONTACT: Steven Rosenthal, Environmental
Engineer, Attainment Planning & Maintenance Section, Air Programs
Branch (AR-18J), U.S. Environmental Protection Agency, Region 5, 77
West Jackson Boulevard, Chicago, Illinois 60604,<PHONE_NUMBER>,
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA. This section is arranged as
follows:

I. Definitions
II. Background Information
III. Comments and Responses
IV. Revision to Equation for Normally Distributed but not
Statistically Independent Data
V. What action is EPA taking?
VI. Statutory and Executive Order Reviews

I. Definitions

    For the purpose of this document, we are giving meaning to certain
words or initials as follows:
     The initials BACT mean or refer to Best Available Control
Technology.
     The initials BART mean or refer to Best Available Retrofit
Technology.
     The initials CAA mean or refer to the Clean Air Act.
     The initials CBI mean or refer to Confidential Business
Information.
     The initials CEMS means or refers to continuous emission
monitoring system.
     The initials CFD mean or refer to computational fluid
dynamic.
     The words EPA, we, us, or our mean or refer to the United
States Environmental Protection Agency.
     The initials FIP mean or refer to Federal Implementation
Plan.
     The initials LNB mean or refer to low-NOX
burners.
     The initials MACT mean or refer to Maximum Achievable
Control Technology.
     The initials MCEA means or refers to the Minnesota Center
for Environmental Advocacy.
     The initials MMBtu mean or refer to million British
thermal units.
     The initials MW mean or refer to megawatts.
     The initials NAAQS mean or refer to National Ambient Air
Quality Standards.
     The initials NESHAP mean or refer to National Emission
Standards for Hazardous Air Pollutants.
     The initials NSPS mean or refer to Standards of
Performance for New Stationary Sources.
     The initials NOX mean or refer to nitrogen
oxides.
     The initials NPCA means or refers to the National Parks
Conservation Association.
     The initials NTAA means or refers to the National Tribal
Air Association.
     The initials PRB mean or refer to the Powder River Basin.
     The initials RHR mean or refer to the EPA's Regional Haze
Rule.
     The initials RMB mean or refer to RMB Consulting and
Research.
     The initials SCR mean or refer to Selective Catalytic
Reduction.
     The initials SIP mean or refer to State Implementation
Plan.
     The initials SO2 mean or refer to sulfur
dioxide.
     The initials UPL mean or refer to Upper Prediction Limit.

II. Background Information

A. Requirements of the Clean Air Act and EPA's Regional Haze Rule

    In section 169A of the 1977 Amendments to the CAA, Congress created
a program for protecting visibility in the nation's national parks and
wilderness areas. This section of the CAA establishes as a national
goal the ``prevention of any future, and the remedying of any existing,
impairment of visibility in mandatory Class I Federal areas \1\ which
impairment results from manmade air pollution.'' Congress added section
169B to the CAA in 1990 to address regional haze issues. EPA
promulgated a rule to address regional haze on July 1, 1999. 64 FR
35714 (July 1, 1999), codified at 40 CFR part 51, subpart P (herein
after referred to as the ``Regional Haze Rule''). The RHR revised the
existing visibility regulations to add provisions addressing regional
haze impairment and established a comprehensive visibility protection
program for Class I areas. The requirements for regional haze, found at
40 CFR 51.308 and 51.309, are included in EPA's visibility protection
regulations at 40 CFR 51.300-309.
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    \1\ Areas designated as mandatory Class I Federal areas consist
of national parks exceeding 6000 acres, wilderness areas and
national memorial parks exceeding 5000 acres, and all international
parks that were in existence on August 7, 1977. 42 U.S.C. 7472(a).
In accordance with section 169A of the CAA, EPA, in consultation
with the Department of Interior, promulgated a list of 156 areas
where visibility is identified as an important value. 44 FR 69122
(November 30, 1979). The extent of a mandatory Class I area includes
subsequent changes in boundaries, such as park expansions. 42 U.S.C.
7472(a). Although states and tribes may designate as Class I
additional areas which they consider to have visibility as an
important value, the requirements of the visibility program set
forth in section 169A of the CAA apply only to ``mandatory Class I
Federal areas.'' Each mandatory Class I Federal area is the
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i).
When we use the term ``Class I area'' in this action, we mean a
``mandatory Class I Federal area.''
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B. Best Available Retrofit Technology (BART)

    Section 169A of the CAA directs states, or EPA if developing a FIP,
to

evaluate the use of retrofit controls at certain larger, often
uncontrolled, older stationary sources in order to address visibility
impacts from these sources. Specifically, section 169A(b)(2)(A) of the
CAA requires EPA to develop a FIP that contains such measures as may be
necessary to make reasonable progress toward the natural visibility
goal, including a requirement that certain categories of existing major
stationary sources \2\ built between 1962 and 1977 procure, install,
and operate the BART as determined by EPA. Under the RHR, states (or in
the case of a FIP, EPA) are directed to conduct BART determinations for
such ``BART-eligible'' sources that may reasonably be anticipated to
cause or contribute to any visibility impairment in a Class I area.
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    \2\ The set of ``major stationary sources'' potentially subject
to BART is listed in CAA section 169A(g)(7), and includes ``taconite
ore processing facilities.''
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    On July 6, 2005, EPA published the Guidelines for BART
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR
part 51 (hereinafter referred to as the ``BART Guidelines'') to assist
states and EPA in determining which sources should be subject to the
BART requirements and in determining appropriate emission limits for
each applicable source. 70 FR 39104.
    The process of establishing BART emission limitations includes
identifying those sources that meet the definition of ``BART-eligible
source'' set forth in 40 CFR 51.301,\3\ determining which of these
sources ``emits any air pollutant which may reasonably be anticipated
to cause or contribute to any impairment of visibility in any such
area'' (a source which fits this description is ``subject to BART''),
and, for each source subject to BART, identifying the best available
type and level of control for reducing emissions.
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    \3\ BART-eligible sources are those sources that have the
potential to emit 250 tons or more of a visibility-impairing air
pollutant, were not in operation prior to August 7, 1962, but were
in existence on August 7, 1977, and whose operations fall within one
or more of 26 specifically listed source categories. 40 CFR 51.301.
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    States, or EPA if developing a FIP, must address all visibility-
impairing pollutants emitted by a source in the BART determination
process. The most significant visibility impairing pollutants are
SO2, NOX, and particulate matter.
    A SIP or FIP addressing regional haze must include source-specific
BART emission limits and compliance schedules for each source subject
to BART. Once a state or EPA has made a BART determination, the BART
controls must be installed and operated as expeditiously as
practicable, but no later than five years after the date of the final
SIP or FIP. See CAA section 169A(g)(4) and 40 CFR 51.308(e)(1)(iv). In
addition to what is required by the RHR, general SIP requirements
mandate that the SIP or FIP include all regulatory requirements related
to monitoring, recordkeeping, and reporting for the BART controls on
the source. See CAA section 110(a).

C. Regulatory and Legal History of the 2013 Taconite FIP

    On February 6, 2013, EPA promulgated a FIP (78 FR 8706) that
included BART limits for taconite furnaces subject to BART in Minnesota
and Michigan. EPA took this action because Minnesota and Michigan had
failed to meet a statutory deadline to submit their Regional Haze SIPs
and subsequently failed to require BART at the taconite facilities.
Cliffs, ArcelorMittal, and the State of Michigan petitioned the Eighth
Circuit Court of Appeals for review of the FIP, and, on May 17, 2013,
Cliffs and ArcelorMittal filed a joint motion for stay of the final
rule, which was granted by the Eighth Circuit on June 14, 2013, and is
still in effect.
    EPA received petitions for reconsideration of the 2013 Taconite FIP
from the National Mining Association on March 8, 2013, ArcelorMittal on
March 22, 2013, the State of Michigan on April 1, 2013, Cliffs on April
3, 2013, Congressman Richard M. Nolan on April 8, 2013, the State of
Minnesota on April 8, 2013, and United States Steel Corporation (U.S.
Steel) on November 26, 2013.
    In a related action, EPA published a final partial disapproval of
the Michigan and Minnesota Regional Haze SIPs on September 30, 2013 (78
FR 59825), for failure to require BART for SO2 and
NOX emissions from taconite furnaces subject to BART. By
petitions dated November 26, 2013, Cliffs and U.S. Steel petitioned EPA
pursuant to section 307(d)(7)(B) of the CAA for reconsideration of
EPA's partial disapproval of the Michigan and Minnesota Regional Haze
SIPs. Further, Cliffs, ArcelorMittal, Michigan, and U.S. Steel
petitioned the Eight Circuit Court of Appeals for review of the final
rule partially disapproving the Michigan and Minnesota Regional Haze
SIPs.
    EPA subsequently reached a settlement agreement with Cliffs,
ArcelorMittal, and Michigan regarding issues raised by these parties in
their petitions for review and reconsideration. Notice of the
settlement was published in the Federal Register on January 30, 2015
(80 FR 5111), and the settlement agreement was fully executed on April
9, 2015. Pursuant to the settlement agreement, EPA granted partial
reconsideration of the 2013 Taconite FIP on July 2, 2015, based on new
information raised in Cliffs', ArcelorMittal's, and Michigan's
petitions for reconsideration. EPA did not grant reconsideration of the
2013 SIP disapprovals because EPA continues to believe that BART for
taconite plants involves significant reductions of NOX and
SO2 emissions that were not required in the Michigan and
Minnesota SIPs.

III. Comments on Proposed Action and Responses

    On October 22, 2015, EPA published a Federal Register action
entitled ``Air Plan Approval; Minnesota and Michigan; Revision to
Taconite Federal Implementation Plan; Proposed Rule'' (80 FR 64160),
which proposed to revise the 2013 Taconite FIP with respect to the BART
emission limitations and compliance schedules for the following
taconite plants: United Taconite, Hibbing Taconite, Tilden Mining, and
ArcelorMittal Minorca Mine. Cliffs is the owner and operator of the
United Taconite and Tilden Mining facilities and part owner and
operator of Hibbing Taconite. ArcelorMittal is the owner and operator
of the Minorca Mine facility and a part owner of the Hibbing Taconite
facility.
    EPA proposed to revise the NOX limits and compliance
schedules for all four facilities and to revise the SO2
requirements for Tilden Mining and United Taconite in response to new
information that became available after the close of the public comment
period of the 2013 FIP. Specifically, Cliffs and ArcelorMittal
submitted information to EPA that suggested high-stoichiometric LNBs,
which formed the basis of the original NOX limits, posed
serious technical hurdles. Consequently, EPA proposed to determine that
BART for taconite facilities was low-stoichiometric LNBs (for grate
kilns) and a combination of water and steam injection and pre-
combustion technologies (for straight-grate kilns) and proposed revised
NOX limits based upon these technologies. Cliffs also
submitted information showing that United Taconite could not burn very
low-sulfur coal without challenges and that Tilden intended to burn
mixed low-sulfur fuels instead of 100% natural gas. As a result, EPA
proposed to revise the SO2 limits for these facilities.
    The public comment period on the proposal ended on December 23,
2015. EPA received comments from the National Park Service of the
United

States Department of Interior, the National Parks Conservation
Association (NPCA), the Minnesota Center for Environmental Advocacy
(MCEA), United States Steel Corporation, ArcelorMittal USA LLC, the
Forest Service of the United States Department of Agriculture (USDA),
Cliffs Natural Resources, and the Fond du Lac Band of Lake Superior
Chippewa. The National Tribal Air Association (NTAA) requested an
extension of the public comment period of 120 days. A 30-day extension
of the public comment period was provided, but NTAA did not
subsequently submit comments. EPA fully considered all of the comments
and responds to each comment below. Based on our consideration of the
comments, we are finalizing the NOX and SO2
emission limits and compliance schedules as proposed, with two minor
exceptions explained in Section V.

A. Comments by the Forest Service

    Comment: The Forest Service disagreed with EPA's determination that
LNBs should be eliminated as a potential BART option for straight-grate
kilns. The Forest Service stated that LNBs are included in the permits
for straight-grate furnaces for Essar Steel (Essar) in Minnesota and
Magnetation in Indiana, which (unlike Essar) has commenced operation.
The permit limits for each of the two LNB-equipped straight-grate kilns
are 0.25 lbs NOX/MMBTU, which is lower than the limits
proposed by EPA.
    Response: EPA disagrees that the situations at Essar and
Magnetation provide sufficient evidence that LNBs would be technically
feasible at the Minorca Mine and Hibbing facilities. Essar and
Magnetation were subject to the BACT requirement that applies to new
and modified sources. Consequently, these facilities were able to
integrate LNBs into the design and construction of their furnaces. In
contrast, the furnaces at Minorca Mine and Hibbing were not designed to
accommodate LNBs. As discussed in the proposal, EPA eliminated LNBs
from consideration due to the technical challenges associated with a
retrofit application on the unique straight-grate kilns at Minorca Mine
and Hibbing. We also note that the Essar straight-grate furnace is
still not operational, and Magnetation is not an iron ore processing
facility and therefore is not classified as a taconite facility as
defined by the taconite MACT (40 CFR part 63 subpart RRRRR). While
Magnetation's permit limit is 0.25 lbs NOX/MMBTU, the
results from an August-September 2015 test indicate emissions ranging
from 0.773 lbs NOX/MMBTU to 1.304 lbs NOX/MMBTU
at that facility. Finally, we note that we are finalizing an initial
emission limit of 1.2 lbs NOX/MMBTU (subject to upward
revision only in unlikely scenarios) for the Minorca Mine and Hibbing
furnaces, which is consistent with the limit in our 2013 FIP, but based
on the installation of different technologies.
    Comment: The Forest Service stated that EPA seems to assume that
the only way to meet the existing 0.6 percent sulfur limit is to use
western sub-bituminous coal, which will not work in the furnace due to
its lower heating value. The Forest Service did a quick search of U.S.
coal data (US DOE, NETL, Detailed Coal Specifications, Quality
Guidelines for Energy System Studies, Final Report, DOE/NETL-401/
012111, January 2012, page 31) and could find no eastern bituminous
coal at 0.6 percent sulfur, but was able to find a low-volatile,
eastern bituminous coal with very high heating value at 0.66 percent
sulfur, which is far below the new limit proposed by EPA for United
Taconite of 1.5 percent sulfur. The Forest Service stated that if an
adjustment is warranted to the existing limit, it should be based on
low-sulfur content eastern bituminous coal, such as the one at 0.66
percent sulfur.
    Response: EPA disagrees with this comment. The primary
SO2 emission limit for BART at United Taconite is the 529
lbs SO2/hr aggregate limit on lines 1 and 2. This BART
limit, which is based upon the use of low-sulfur fuels (a combination
of natural gas and coal), will result in 1900 tons per year of
SO2 reductions. In contrast, the 1.5 percent sulfur limit is
an operational limit that EPA imposed after Cliffs requested an
adjustment to its baseline emission rate to be used in evaluating
potential BART controls. Under the BART guidelines, the baseline
emission rate ordinarily should represent a realistic depiction of
anticipated annual emissions for the source based upon actual emissions
from a baseline period. See 40 CFR part 51, appendix Y. However, when
future operating parameters, such as type of fuel, will differ from
past practice, and if this projection has a deciding effect in the BART
determination, then the operating parameter must be made into an
enforceable limitation. Id. EPA imposed the original 0.60 percent
sulfur limit on the coal burned at United Taconite to comply with this
provision. However, Cliffs indicated in its petition for
reconsideration that 0.60 percent sulfur coal posed several issues for
its furnaces. As a result, the EPA proposed to increase the operational
limit to 1.5 percent sulfur, but this change will not have an effect on
emissions at United Taconite due to the 529 lbs SO2/hr
limit. In essence, United Taconite will now be required to burn more
natural gas and less coal (or all gas) to meet its BART limit than the
facility would have under a 0.60 percent sulfur limit.
    Comment: The Forest Service asked for an explanation as to why
Minorca Mine and Tilden have the longest deadlines for compliance when
they each have only one furnace at their facility.
    Response: To establish an overall compliance schedule that is as
expeditious as practicable, we grouped the furnaces according to
whether they are straight-grate kilns or grate kilns, not according to
which facility they belong. By grouping furnaces according to design
and function rather than facility, Cliffs and ArcelorMittal will be
able to take advantage of the experience gained from the first
installation of NOX reduction technologies at a straight-
grate kiln and grate kiln at the other furnaces. For example, Tilden
will be able to take advantage of the experience of the earlier
installation of a low-stoichiometric LNB on a grate kiln at United
Taconite, while ArcelorMittal will be able to take advantage of the
earlier installation of NOX reduction technologies on a
straight-grate kiln at Hibbing. We believe that this staggered schedule
is necessary because, although the selected NOX controls
have been subject to extensive engineering studies, they have not been
used on taconite furnaces in the United States to date. Such experience
is necessary to ensure proper operation of these furnaces. Improper
burner operation could adversely affect heat distribution throughout
the furnace as well as pellet quality.
    Comment: The Forest Service stated that it would like the
opportunity to review and comment on the final emission limits.
    Response: EPA has provided an extremely detailed and objective
step-by-step procedure that will be used for determining the final
emission limits. The notice of proposed rulemaking provided adequate
information about the basis and timing of the final limits such that no
further proposals will be necessary. The equations and an explicit
explanation of how the final limits will be established are contained
in the proposal, so the Forest Service could have raised any concerns
during the public comment period. EPA is taking this approach in order
to expedite the establishment of final enforceable limits for these
facilities within the context of a process that provides reasonable
time to design and install emission controls,

to obtain data needed for determining control effectiveness, and to
minimize the time then needed to establish final enforceable limits.
EPA has carefully considered the Forest Service's comments, but does
not believe that a second comment period is necessary.
    Comment: The Forest Service requested a description of how plant
shutdowns will be handled.
    Response: EPA is unsure what the commenter means by ``plant
shutdowns,'' but presumes that the Forest Service may be concerned that
the emission limits could be relaxed during a shutdown. No special
consideration has been given to plant shutdowns in this respect. The
NOX limits are based on the production level and the
quantity of fuel burned.
    Comment: The Forest Service asked EPA to describe what will be done
if adequate data are not collected within the timeframe envisioned in
the schedule to establish a final emission limit.
    Response: The eight-month testing period, during which controls
will be in place and CEMS will be operational, should provide ample
time for collecting data adequate to establish a final limit.
    Comment: The Forest Service asked EPA to specify what design
parameters will be monitored for the different control technologies.
    Response: The design parameters will be established in the
engineering reports that are required by the settlement agreement and
this action. We anticipate that the percent stoichiometric primary
combustion air and gas/coal ratio when co-firing will be important
variables.

B. Comments by the National Park Service

    Comment: The National Park Service, as well as NPCA and MCEA,
commented on the technical feasibility of controlling NOX
using SCR and encouraged EPA to further evaluate various configurations
of SCR, including tail-end SCR with gas stream reheat (hereinafter
referred to as ``SCR with reheat'').
    Response: There are several air pollution control technology
analyses involving the potential use of SCR and SCR with reheat on
indurating furnace hood exhaust. In these analyses (Magnetation BACT,
Essar BACT, and Tilden BART), SCR with reheat was rejected for not
being cost-effective, while upstream SCR was rejected as technically
infeasible due to the likelihood that the exhaust stream would foul the
catalyst.
    In a study conducted by Hatch for U.S. Steel, SCR with reheat was
considered as a potential control option, but further discussion with
potential vendors resulted in the determination that SCR with reheat is
not a technically feasible control option for taconite indurating
furnaces. One potential vendor, Mitsubishi Power Systems, cited
temperature and layout as factors rendering SCR with reheat less than
optimal for NOX control from U.S. Steel's Minntac taconite
indurating furnaces. LKAB, a taconite facility in Sweden, has an SCR
with reheat on its KK4 taconite pelletizing line. Alstom, the SCR
vendor for LKAB, declined twice to bid on an SCR with reheat at
Minntac, citing technical difficulties with the SCR with reheat at
LKAB. These difficulties included operating within the narrow
temperature range required by SCR with reheat. Further, LKAB is looking
into process optimization and better burners to reduce NOX
as opposed to installing another SCR with reheat in the future. It is
important to note that SCR with reheat, even if it were technically
feasible, would result in additional energy and environmental costs in
the form of increased usage of natural gas and greenhouse gas
emissions, respectively. While increased energy and environmental
penalties are not preclusive, they further weigh against any additional
analysis of SCR with reheat as a viable option for indurating furnaces
at this time. We expect Minnesota and Michigan to reevaluate SCR with
reheat as a potential option for making reasonable progress in future
planning periods, but reject the technology as BART for the Minnesota
and Michigan taconite facilities at this time.
    Comment: The National Park Service concurred with the maximum 3.0
lbs NOX/MMBTU limit when burning natural gas only at grate
kilns. However, the National Park Service did not believe that allowing
NOX emissions to increase by 87 percent above expected
levels when burning a gas/coal mix at grate kilns is justified.
    Response: Low-stoichiometric LNBs, as designed by FCT Combustion
(FCT), are designed to reduce NOX while maintaining pellet
quality and production and optimizing fuel efficiency. As a result,
this LNB was selected to establish BART limits for Cliffs' grate-kiln
furnaces. FCT's computational fluid dynamic (CFD) modeling for co-
firing at 30 percent gas and 70 percent coal indicated a reduction from
a base case of 1.6-5.4 lbs NOX/MMBTU with a typical baseline
value of 2.5 lbs NOX/MMBTU, to 2.04 lbs NOX/
MMBTU. Therefore, an increase from 2.04 to 2.5 lbs NOX/MMBTU
is a 23 percent increase above expected levels, which is more
meaningful than the 67 percent increase (not 87 percent) above the low
end of the range of the final emission limits. It should be noted that,
in addition to the uncertainty resulting from the lack of experience in
the use of low-stoichiometric LNBs, there is additional uncertainty
because the CFD modeling was only performed for co-firing at 30 percent
gas and 70 percent coal. Furthermore, a rigorous demonstration would
have to be made that 1.5 lbs NOX/MMBTU cannot be met before
the limit is adjusted and an alternative final limit is set.
    Comment: The National Park Service was concerned that, although the
proposed FIP requires the NOX reduction technologies for the
straight-grate furnaces at Minorca Mine and Hibbing be designed to meet
a limit of 1.2 lbs NOX/MMBTU, EPA is proposing to increase
the final limit up to 1.8 lbs NOX/MMBTU if a rigorous
demonstration is made that the 1.2 lbs NOX/MMBTU limit
cannot be met. This represents a 50 percent increase above the expected
emission rate and no justification is provided for such a large
``safety margin.''
    Response: As discussed in the proposed rulemaking, EPA is confident
that Minorca Mine and Hibbing can meet a limit of 1.2 lbs
NOX/MMBTU based upon the engineering report prepared for
ArcelorMittal that assesses the use of water and steam injection and
pre-combustion technologies. However, because this suite of
technologies has not previously been used on straight-grate kilns, some
uncertainty remains regarding the potential effect on pellet quality.
As a result, EPA has provided a procedure by which the final limits for
Minorca Mine and Hibbing could be revised upwards to as much as 1.8 lbs
NOX/MMBTU. It is important to note, however, that EPA has
included rigorous requirements that must be met before any relaxing of
the initial 1.2 lbs NOX/MMBTU limit would be allowed.
    Comment: The National Park Service stated that EPA has the
authority to limit the sulfur content of the fuels already fired at
United Taconite. The National Park Service understood that United
Taconite has identified problems with the characteristics of the 0.6
percent sulfur coal originally proposed by EPA and the compatibility of
that coal with the United Taconite furnace. The National Park Service
cited EPA's statement that it ``is also establishing a limitation on
the coal to be used by requiring the coal have a sulfur content

no greater than 1.5 percent sulfur by weight based on a monthly block
average.'' However, the National Park Service stated that it is aware
of eastern bituminous coals that have much lower sulfur contents and
requested that EPA evaluate the potential for combustion of such coals
at United Taconite.
    Response: EPA disagrees with this comment. The primary
SO2 emission limit for BART at United Taconite is the 529
lbs SO2/hr aggregate limit on lines 1 and 2. This BART
limit, which is based upon the use of low-sulfur fuels (a combination
of natural gas and coal), will result in 1900 tons per year of
SO2 reductions. In contrast, the 1.5 percent sulfur limit is
an operational limit that EPA imposed after Cliffs requested an
adjustment to its baseline emission rate to be used in evaluating
potential BART controls. Under the BART guidelines, the baseline
emission rate ordinarily should represent a realistic depiction of
anticipated annual emissions for the source based upon actual emissions
from a baseline period. See 40 CFR part 51, appendix Y. However, when
future operating parameters, such as type of fuel, will differ from
past practice, and if this projection has a deciding effect in the BART
determination, then the operating parameter must be made into an
enforceable limitation. Id. EPA imposed the original 0.60 percent
sulfur limit on the coal burned at United Taconite to comply with this
provision. However, Cliffs indicated in its petition for
reconsideration that 0.60 percent sulfur coal posed several issues for
its furnaces. As a result, the EPA proposed to increase the operational
limit to 1.5 percent sulfur, but this change will not have an effect on
emissions at United Taconite due to the 529 lbs SO2/hr
limit. In essence, United Taconite will now be required to burn more
natural gas and less coal (or all gas) to meet its BART limit than the
facility would have under a 0.60 percent sulfur limit.
    Comment: The National Park Service stated that EPA was apparently
proposing to use hourly emission rates measured by a CEMS to derive the
UPL. The National Park Service questioned the appropriateness of basing
the UPL on hourly values if EPA is setting a 30-day (or 720-hour)
rolling average limit. The National Park Service was concerned that the
use of hourly values would introduce excess variability into the
calculation and could lead to a higher UPL.
    Response: When the UPL equation for normally distributed and
statistically independent data is used, the average , standard
deviation (s), and number of values (n) are based on the hourly data.
The term number of values used to calculate the test average) is based
on the compliance period, i.e., 720 for a 720-hour average and not 1.
This results in a lower and more stringent UPL than if 1. However, when
setting a 720-hour average emission limit using the nonparametric
equation, the data set used would be the 720-hour averages rather than
the raw hourly data.

C. Comments by the National Parks Conservation Association (NPCA)

1. NPCA Incorporated the Comments Submitted by the National Park
Service
    Comment: NPCA restated the National Park Service comments as
follows:

--SCR remains a feasible technical option for limiting NOX
from taconite facilities. While two SCR vendors declined to bid on the
NOX reduction testing at Minntac, this is an insufficient
basis to reject SCR across the taconite industry. EPA should revisit
this decision and evaluate various configurations of SCR that would
serve to further reduce NOX emissions beyond the limits in
the proposed settlement.
--EPA's proposed NOX limits for the gas/coal scenario at
United Taconite and Tilden are improper because they are up to 87
percent higher than the limits in the 2013 FIP.
--EPA's proposed NOX limits for Hibbing and Minorca Mine are
improper because they are up to 50 percent higher than the limits in
the 2013 FIP.
--EPA should require the use of an alternative low-sulfur coal at
United Taconite.

    Response: EPA has responded in detail to these comments in
responses to the comments by the National Park Service (see above).
    Comment: NPCA stated that the proposal specifies that increased
limits are permissible where the industry makes a rigorous
demonstration that lower limits cannot be met. NPCA requested that any
such demonstration be made available to the public for review and
comment.
    Response: EPA has provided an extremely detailed and objective
step-by-step procedure for determining the final emission limits. The
notice of proposed rulemaking provided adequate information about the
basis and timing of the final limits such that no further proposals
will be necessary. EPA is taking this approach in order to expedite the
establishment of final enforceable limits for these facilities within
the context of a process that provides reasonable time to design and
install emission controls, to obtain data needed for determining
control effectiveness, and to minimize the time then needed to
establish final enforceable limits. The proposal encouraged commenters
to comment on any issues that might be anticipated to arise at any
point in the process described in the proposal, and NPCA has not
identified any such issues.
2. NPCA Incorporated Its March 2, 2015 Comments Regarding the
Settlement Agreement
    Comment: NPCA stated that the changes in emission limits between
the 2013 FIP and the settlement agreement appear to significantly
weaken the terms of the 2013 FIP because the emission limits are far
less stringent. Although NPCA did not have the necessary level of
detailed information to perform a precise comparison, NPCA's rough
calculations indicated that the limitations in attachment A of the
settlement agreement would allow for pollution at or above the actual
baseline emissions from the taconite facilities, that is, they
represent no reduction (or at a minimum, no significant reduction) in
pollution.
    Response: As discussed in the five-step BART determinations in the
proposal, there are significant emission reductions from the revised
limits. There will be an estimated total of 3,000 tons per year of
NOX reductions from Tilden and United Taconite, a total of
7,400 tons per year of NOX reductions from Minorca Mine and
Hibbing, 1,900 tons per year of SO2 reductions from United
Taconite, and 300 tons of SO2 reductions from Tilden. The
only NOX emission limits that are definitely less stringent
than those in the 2013 FIP are the NOX emission limits for
Tilden and United Taconite when burning solely natural gas. The final
NOX emission limits for Hibbing and Minorca Mine, as well as
Tilden and United Taconite when co-firing coal and natural gas, are
expected to be the same as, or close to, the 2013 FIP limits. There may
also be an increase in SO2 emissions from Tilden, but this
should be a fairly small increase as Tilden will be solely burning
natural gas and very low (0.6 percent) sulfur coal.
    Comment: NPCA argued that the timeframes for compliance are
significantly longer than in the 2013 FIP.
    Response: The compliance schedule is generally similar to the FIP
except that implementation has been delayed because of the court-
imposed stay. The main differences between the two schedules are that
Tilden must install controls within 50 months (compared with 26 months
in the 2013 FIP) and Minorca Mine must install controls

within 44 months (compared with 26 months in the 2013 FIP). The
staggered compliance schedule, which includes additional time for
Tilden and ArcelorMittal, is necessary because the NOX
controls selected as BART have not been used on taconite furnaces in
the United States. Such experience is necessary to ensure proper
operation of these furnaces. The planned controls could adversely
affect heat distribution throughout the furnace as well as pellet
quality.
    Comment: NPCA stated that, in proposing the settlement, EPA offered
no support to suggest why such a significant weakening of much needed
and statutorily required limits was appropriate. NPCA was thus at a
loss to comment on the rationale behind the changes.
    Response: As discussed in a prior response, EPA does not agree that
there has been a significant weakening of the requirements for taconite
facilities. EPA's basis for all changes was contained in the proposed
FIP revision and its associated docket.
    Comment: NPCA stated that EPA must provide documentation of the
reasons for the proposed changes in the form of publicly available
information. EPA cannot rely strictly on confidential information,
which does not allow the public to review and consider the changes
proposed.
    Response: Publicly available information in support of the FIP is
contained in the docket.
    Comment: NPCA stated that the settlement referenced ``equitable
treatment of facilities not included in this settlement.'' This would
appear to refer to the taconite facilities covered by the 2013 FIP but
not included in the settlement. To the extent that this statement
refers to the potential weakening of limits imposed at other facilities
in the taconite FIP, the increase in pollution that appears in the
settlement is all the more concerning.
    Response: EPA has not proposed to change the emission limits for
other facilities covered by the 2013 FIP at this time.
    Comment: NPCA stated that the timeframe for compliance detailed in
the settlement agreement was inappropriate. The CAA requires that
controls required under BART be implemented within five years of the
final rule. In this case, the rule was finalized in January 2013, so
compliance with emission limits must be by January 2018.
    Response: We disagree with this comment. Section 169A(g)(4) of the
CAA requires compliance with BART emission limits no later than five
years after ``the date of promulgation of a . . . [FIP] revision.'' In
this final rule, we are promulgating a revision to the 2013 FIP that
includes new BART determinations based on new technologies. These BART
determinations fully supersede the determinations that were made in the
2013 FIP. The taconite facilities must comply with the new BART
emission limits in a staggered schedule that we have determined is as
expeditious as practicable. Full compliance at all facilities will be
achieved no later than five years from the date of the promulgation of
this FIP revision.

D. Comments by Cliffs Natural Resources

    Comment: Cliffs supported the proposed FIP, including the initial
limits, the staggered compliance schedule, and the formula for setting
final limits if the initial limits cannot be achieved without adverse
impacts on pellet quality. However, Cliffs objected to EPA's statement
in the proposed FIP preamble that ``there are no significant costs or
environmental impacts'' associated with the selected BART technologies.
Cliffs will be required to expend millions of dollars to design and
implement changes to its furnaces. There are also costs associated with
lost production during downtime and shakedown, as well as the potential
for additional fuel consumption when the BART technologies are
operational.
    Response: EPA acknowledges that there will be costs associated with
the BART control technologies employed by Cliffs. EPA's full statement
in the preamble was that ``there are no significant costs or
environmental impacts associated with this technology that would
necessitate its elimination from consideration as BART.'' EPA continues
to believe that the costs, energy, and non-air quality impacts
associated with the selected BART controls are reasonable.
    Comment: Cliffs stated that EPA's proposal included a new
requirement to report CEMS and pellet quality data at the end of a
period that did not fall within the preceding calendar quarter within 7
days of the close of the period. Reporting this information within 7
days is impracticable, as it does not provide the facility sufficient
time to complete the appropriate laboratory analysis and quality
assurance expected for the data. Cliffs acknowledged EPA's need to
include a provision to address the timely reporting of data, but
requested that the reporting obligation be changed from 7 days to 30
days to allow for quality assurance checks.
    Response: Using United Taconite Line 2 as an example, the
settlement agreement states that, 44 months from the effective date of
the rule, Cliffs must provide results from pellet quality analyses no
later than 30 days from the end of each calendar quarter until 52
months from the effective date of the rule. No later than 55 months
after the effective date of the rule, EPA will take final agency action
by publishing the NOX limits in the Federal Register.
Assuming that the effective date of the rule is June 15, 2016, then 52
months from the effective date is October 15, 2020, and 55 months is
January 15, 2021. The end of the quarter would be December 31, 2020, so
under the settlement language, the pellet quality data from October 1
through October 15, 2020, would not be due until January 30, 2021,
which is too late to be considered in establishing the final emission
limit. According to the language in the proposal, the pellet quality
analyses would need to be submitted to EPA by October 22, 2020.
Accepting Cliffs' suggested revision from 7 to 30 days would require
the pellet quality analysis to be submitted to EPA by November 14,
2020. EPA accepts Cliffs' basis for increasing the reporting
requirement from 7 to 30 days and will make this revision in the final
FIP because it will not significantly interfere with expeditiously
setting the final limits.
    Comment: Cliffs stated that United Taconite's pellet quality
reporting obligations in the proposed FIP mistakenly refer to
``Tilden's ISO 9001 quality management system'' but should refer to
``United Taconite's ISO 9001 quality management system.''
    Response: EPA acknowledges the error and has made the correction in
the final FIP.

E. Comments by the Fond du Lac Band of Lake Superior Chippewa

    Comment: The Band urged a fair, scientifically sound, and feasible
process for all stakeholders, including affected and surrounding
communities. The taconite industry should not be allowed to dictate its
own compliance schedule or prolong compliance with Federal laws and
regulations.
    Response: EPA agrees with this comment and has implemented a
process to establish final BART limits based upon the most current,
relevant, and scientifically sound information available. The taconite
plant owners were in a unique position to acquire and provide the
needed scientific information and understandably had motivation to do
so. However, they are not dictating their own compliance schedule.

    Comment: The Band argued that the emission limits in the 2013 FIP
are more reasonable in terms of protecting visibility than the limits
proposed in the revised FIP.
    Response: While we acknowledge that a few of the emission limits in
the 2013 FIP were more stringent than the limits in our proposed FIP
revision, and were thus more protective of visibility, we disagree that
the original limits were more reasonable. For the reasons explained in
our proposal, new information provided by the taconite companies shows
that the technology on which the 2013 FIP limits were based, high-
stoichiometric LNBs, would adversely affect pellet quality. As a
result, we proposed new BART determinations based on new technologies.
These technologies will still result in significant emission
reductions, improving visibility in the Class I areas in Minnesota and
Michigan.
    Comment: The Band stated that the compliance schedule in the 2013
FIP was more reasonable from a health protection standpoint. The Band
stated that it preferred the 2013 FIP schedule over the longer
compliance schedule in the proposed FIP revision. Alternatively, a
compromise schedule between the original schedule and the proposed
schedule would be acceptable.
    Response: Please see our response to a similar comment from NPCA.
    Comment: The Band stated that Eastern bituminous coals are
available that could meet both the requirements for a low-sulfur coal
(0.66%) and a very high heating value (US DOE, NETL, Detailed Coal
Specifications, Quality Guidelines for Energy System Studies, Final
Report, DOE/NETL-401/012111, January 2012, page 31).
    Response: Please see our response to a similar comment from the
Forest Service.
    Comment: The Band stated that SCR is considered the best available
retrofit technology that has been used at other coal facilities and
could feasibly reduce NOX emissions for taconite furnaces.
The Band agreed with the National Park Service that the use of tail-end
SCR with steam reheat should be evaluated for BART.
    Response: Please see our response to a similar comment from the
National Park Service.
    Comment: The Band noted that EPA proposed to set limits for United
Taconite and Tilden of 3.0 lbs NOX/MMBTU when burning
natural gas and 2.5 lbs NOX/MMBTU when burning a gas/coal
mix if the presumptive limits of 2.8 lbs NOX/MMBTU and 1.5
lbs NOX/MMBTU, respectively, cannot be met. The Band noted
that a limit of 2.5 lbs NOX/MMBTU (gas coal mix) is 67
percent higher than the predicted emission rate of 1.5 lbs
NOX/MMBTU. The Band acknowledged that some uncertainty is
involved in developing the use of a new control technology, but argued
that this range of emission limits is too large.
    Response: Please see our response to a similar comment from the
National Park Service.
    Comment: The Band stated that EPA recently implemented a national
policy on Environmental Justice for Working with Federally Recognized
Tribes and Indigenous Peoples. EPA must uphold its duties to protect
the interests of tribes and their treaty rights and explain how the
proposed FIP complies with EPA's existing guidance and policies with
Federally Recognized Tribes and Indigenous Peoples.
    Response: The U.S. Constitution defines treaties as part of the
supreme law of the land with the same legal force as Federal statutes.
Treaties are to be interpreted in accordance with the Federal Indian
canons of construction, a set of long-standing principles developed by
courts to guide the interpretation of treaties between the U.S.
government and Indian tribes. As the Supreme Court has explained,
treaties should be construed liberally in favor of tribes, giving
effect to the treaty terms as tribes would have understood them, with
ambiguous provisions interpreted for their benefit. Only Congress may
abrogate Indian treaty rights, and courts will not find that abrogation
has occurred absent clear evidence of congressional intent.
    EPA has committed to consider all relevant information obtained
during tribal consultation to help ensure that EPA's actions do not
conflict with treaty rights, to help ensure that EPA is fully informed
when it seeks to implement its programs, and to further protect treaty
rights and resources when it has discretion to do so. We have done so
in this action. EPA consulted and coordinated with tribal officials and
provided information on both the 2012 FIP proposal and the current
taconite FIP proposal early in the process of developing this
regulation in order to allow tribal governments to have meaningful and
timely input. EPA provided information to tribes on the rationale for
proposing this regulation in the absence of the states submitting
plans, the potential health and environmental impacts associated with
these facilities, and the emissions reductions to be gained from
implementing this regulation. EPA also took into consideration the
concerns and needs identified by tribal governments during this
process. These consultation and education and outreach efforts began in
August 2012 and continue through the present utilizing forums such as
monthly tribe-EPA conference calls, presentations during annual
meetings and conferences, and one-to-one discussions with EPA subject
matter experts as requested.
    EPA's revision of the FIP is expected to have significant
environmental benefits relative to the SIPs submitted by Michigan and
Minnesota. On-and off-reservation trust resources held by Minnesota
tribes (and other tribes), as recognized in treaties and in Minnesota
v. Mille Lacs Band, 526 U.S. 172 (1999), among other authorities, will
be protected to a greater extent by the controls required in the
amended FIP.

F. Comments by ArcelorMittal

    Comment: ArcelorMittal cited to the preamble to the proposed FIP
revision, which states that ``there are no significant costs or
environmental impacts'' associated with the BART determinations for
Hibbing and Minorca. However, in actuality, the changes necessary to
meet the proposed emission limits will not be without costs and
environmental impacts. ArcelorMittal will be required to expend
millions of dollars to design and implement changes to its straight-
grate furnaces. It will also incur substantial costs associated with
lost production during downtime and shakedown when these technologies
are installed. Once operational, fuel penalties are expected which will
result in increased cost.
    Response: EPA acknowledges that there will be costs associated with
the BART control technologies employed by ArcelorMittal. EPA's full
statement in the preamble was that ``there are no significant costs or
environmental impacts associated with this technology that would
necessitate its elimination from consideration as BART.'' EPA continues
to believe that the costs, energy, and non-air quality impacts
associated with the selected BART controls are reasonable.

G. Comments by United States Steel

    U.S. Steel submitted the following comments to ensure that EPA's
approach to amending the original FIP is applied evenly and fairly and
results in a consistent approach to BART for the taconite industry.
    Comment: U.S. Steel agreed with EPA's decision to develop a case-
by-case approach to BART for indurating furnaces and the Agency's
proposed approach to determining BART for each

individual affected unit, based upon that unit's design and unit-
specific characteristics.
    Response: EPA appreciates U.S. Steel's support.
    Comment: U.S. Steel stated that a similar approach will be
necessary for U.S. Steel's Minntac and Keetac furnaces.
    Response: This comment is outside the scope of this rulemaking.
    Comment: U.S. Steel stated that EPA should consider delaying
finalization of the proposed FIP revision until EPA is prepared to
promulgate similar amendments for all furnaces in the taconite
industry.
    Response: EPA is bound by a settlement agreement to finalize the
proposed FIP revision by March 18, 2016. Furthermore, there have
already considerable delays in the implementation of BART for taconite
indurating furnaces.
    Comment: U.S. Steel stated that if EPA does not delay finalization
of the proposed FIP revision, EPA should continue the stay of effective
dates in the original 2013 FIP pending completion of a similar FIP
amendment for U.S. Steel's Minntac and Keetac facilities.
    Response: This comment is outside the scope of this rulemaking.
    Comment: U.S. Steel stated that EPA should clarify that U.S. Steel
is part owner of Hibbing taconite.
    Response: EPA acknowledges that U.S. Steel is a part owner of the
Hibbing facility.
    Comment: U.S. Steel identified four points made by EPA with which
U.S. Steel disagrees and could not find substantiating information in
the docket. These points are: (1) The smaller preheat burners at
Minntac achieve very low NOX emissions rates (0.1-0.3 lbs
NOX/MMBTU) due to a more favorable NOX reduction
combustion environment in the preheat zone as compared to the firing
end of the kiln; (2) ported kilns significantly change the heat balance
of the furnace; (3) differences in the magnetite content of the ore
body used by Minntac and United Taconite are significant; and 4) high-
stoichiometric LNBs will require more fuel and result in higher
NOX emissions.
    Response: The basis for the above points questioned by U.S. Steel
is presented in the proposed FIP at 80 FR 64163, which is in turn based
upon the November 26, 2013 declaration by Eric Wagner, the Manager of
Process Engineering for Metso Minerals Pyro Division, a ``global expert
in the design of iron ore pelletizing furnaces.'' This declaration is
attached to Cliffs' November 26, 2013 Petition for Administrative
Reconsideration of the Partial Disapproval of Air Quality
Implementation Plans for Regional Haze for the States of Michigan and
Minnesota. Although a hard copy of this document was included in EPA's
Regional docket, and available for inspection at EPA's Region 5 office,
EPA mistakenly did not include this Petition for Reconsideration in the
electronic docket for this rule until after the comment period had
closed. U.S. Steel's comment questions the basis for several of Eric
Wagner's statements regarding factors affecting indurating furnace
operation and NOX emissions. We do not believe this omission
was material, however, because U.S. Steel is seeking information, not
challenging or suggesting revisions to the proposal.
    Comment: U.S. Steel stated that EPA should reconsider the partial
disapproval of Minnesota's SIP.
    Response: This comment is outside the scope of this rulemaking.
    Comment: U.S. Steel stated that, for each of the affected
facilities, there is a schedule prescribed for installation of the
technology and period to collect data to confirm or adjust the limit
based upon the data. The period allows for eight months of data
collection. If an affected facility elects to install the technology
earlier than prescribed by rule, the facility should have the ability
to utilize a more robust data set greater than the eight months
specified. Due to seasonal variations, a facility should have the
ability to use at a minimum 12 months of data if the installation of
technology occurs prior to the compliance date.
    Response: This notice is intended to capture the details agreed
upon by EPA, Cliffs and ArcelorMittal in a settlement agreement. This
comment comes from a commenter who was not party to the settlement
agreement. The detailed compliance schedules contained in the proposed
FIP are based upon the settlement terms agreed to by Cliffs and
ArcelorMittal, who operate all of the taconite furnaces subject to this
FIP. The eight month testing period that was originally proposed was
considered by them to be of sufficient duration to evaluate the
performance of their control systems and their effect on pellet
quality. There is therefore no benefit to extending the testing period
when such an extension is not necessary. The requirements of BART, and
not the compliance schedule in this rule, establish the most
appropriate compliance schedule to be followed by any other taconite
facility.
    Comment: U.S. Steel supported the provision allowing Tilden to
exclude emissions data during a natural gas curtailment that is beyond
a facility's control. These events are typically infrequent, unplanned,
and may cause the facility to operate in a manner that is not typical.
    Response: EPA appreciates U.S. Steel's support for the provision
stating that the SO2 limit for Tilden's grate kiln does not
apply during a natural gas curtailment.

IV. Revision to Equation for Normally Distributed but Not Statistically
Independent Data

    The proposal describes the process for establishing final emission
limits to which the identified facilities shall become subject. As
discussed in the proposal, the final limit must be based on the 95
percent upper predictive limit (UPL) using CEMS data compiled over an
eight-month testing period. The UPL is a statistical technique that
examines an existing set of data points and predicts the chances (i.e.,
the probability) of future data points (in this case, emission rates).
In general terms, the UPL is a value that is calculated from a data set
that identifies the emission rate that a source is meeting and would be
expected to meet a specified percent of the time that the source is
operating. In this case, the UPL will be the emission rate that the
taconite facilities are predicted to be below during 95 out of 100 720-
hour averaging periods. The UPL will be based on data obtained during
an eight-month testing period during which Cliffs and ArcelorMittal are
primarily focused on operating the controls in a manner that does not
adversely affect pellet quality, with a wide variability in emissions
expected. The UPL must be calculated using an equation based on the
average and variance of a data set, the distribution of the data, the
quantity of data points, and the compliance period (e.g., a 720-hour
compliance period).
    The settlement agreement and proposed FIP specified three equations
for determining the UPL depending upon whether the data are normally
distributed and, if so, whether the data are statistically independent
or not statistically independent. In the proposal (the equation numbers
have been changed in the final), Equation 1 applied to normally
distributed, statistically independent data sets; Equation 3 applied to
normally distributed, but not statistically independent data sets; and
Equation 4, the non-parametric UPL equation, applied to data sets that
do not conform to a specific distribution. EPA's statistical guidance
for environmental applications, the ProUCL User Guide,

includes UPL equations for different types of distributions, as well as
a non-parametric equation for data sets that do not conform to a
specific distribution. The guidance does not, however, include an
equation for normally distributed, but not statistically independent
(that is, highly correlated) data. Because Cliffs and ArcelorMittal
were concerned about this latter category of data, we proposed what was
purported to be an appropriate equation for normally distributed, but
not statistically independent data (Equation 3). We subsequently found
that Equation 3 is not valid for large data sets, which is what will
result from eight months of hourly data. When we applied Equation 3 to
a large data set, the resulting UPL was higher than the highest 720-
hour average, a nonsensical and mathematically unreasonable result. We
are therefore eliminating Equation 3 from the final FIP. Instead, we
are requiring use of the fall back non-parametric equation (Equation 4)
for data that are normally distributed, but not statistically
independent.
    We are finalizing the non-parametric equation contained in the
proposal with a clarification regarding the appropriate data set to be
used. As stated above, the UPL equations are used to determine emission
limits. To correctly calculate the UPL using the non-parametric
equation, the data that is ranked from smallest to highest must be in
the same form as the emission limit. The final emission limits are
expressed in terms of 720-hour averages, so the ranked data set used in
the non-parametric equation must be a set of 720-hour averages as well.
Using data sets based upon an averaging time inconsistent with the form
of the emission limit would be an improper use of the equation. For
instance, calculating the 95 percent non-parametric limit using a data
set of ranked one-hour values would establish the emission rate (based
upon a one-hour average) that the source would be predicted to be below
during 95 out of 100 one-hour averaging periods, i.e., an emission
limit based on hourly compliance. The resulting emission limit would be
improper if compliance is to be based upon a 720-hour average. Based
upon our evaluation of existing data sets, using the 95th percentile of
the one-hour values to establish a 720-hour average emission limit
would result in a limit that is higher than the highest 720-hour
average in the data sets, which is clearly inconsistent with the
purpose of a 95 percent UPL.
    To reiterate, the purpose of a 95 percent UPL is to establish an
emission rate that a source is predicted to be below during 95 out of
100 averaging periods. Importantly, however, this does not mean that
the source would be expected to exceed its emission limit five percent
of the time once the limit is in place. During the eight-month testing
period, Cliffs and ArcelorMittal will operate their furnaces and the
new control technologies in a manner that will not interfere with
pellet quality. The furnace operators will be adjusting numerous
variables to optimize control technology performance, which will result
in higher emissions at times. These periods of higher emissions will
factor into the UPL calculation. Once the eight-month testing period is
over, however, the operators will have gained sufficient experience to
run the furnaces and control technologies with fewer adjustments,
meaning less emission variations and lower emissions overall. Using the
95 percent UPL ensures that the final emission limits will be
consistent with the actual emission reduction capabilities of the BART
controls, as required by 40 CFR 51.301, which defines BART as ``the
degree of reduction achievable.'' We also note that the 720-hour
averaging period for the final emission limits will provide
considerable flexibility for the sources. The operators will be able to
continually review CEMS data on an hourly basis and make any necessary
adjustments over the remaining 719 hours to ensure compliance.

V. What action is EPA taking?

    For the reasons stated in the proposed FIP revision and the
response to comments, EPA is finalizing the new BART emission limits
and related requirements for taconite furnaces as proposed, with two
exceptions. First, EPA is revising the requirement to report CEMS and
pellet quality data at the end of a period that did not fall within the
preceding calendar quarter from within 7 days of the close of the
period to within 30 days of the close of the period. This revision will
allow the facilities sufficient time to complete the appropriate
laboratory analyses and quality assurance for the data and will not
significantly interfere with expeditiously setting the final limits.
Second, EPA is replacing the incorrect equation for normally
distributed but not statistically independent data with the non-
parametric UPL equation, which is consistent with EPA guidance. A
summary of our final decision is included in the table below.

                            Summary of Final Emission Limits and Compliance Schedules
----------------------------------------------------------------------------------------------------------------
                                          Compliance     NOX limit for   NOX limit for
                Source                     schedule      gas/coal mix   gas only (lbs/       SO[ihel2] limit
                                           (months)       (lbs/MMBtu)       MMBtu)
----------------------------------------------------------------------------------------------------------------
Tilden................................              60         1.5-2.5         2.8-3.0  500 lbs/hr and 0.6%S.
Hibbing 1.............................              37  ..............         1.2-1.8  ........................
Hibbing 2.............................              55  ..............         1.2-1.8  ........................
Hibbing 3.............................              60  ..............         1.2-1.8  ........................
UTAC 1................................              37         1.5-2.5         2.8-3.0  529 lbs/hr (combined
                                                                                L1&2) and 1.5%S.
UTAC 2................................              55         1.5-2.5         2.8-3.0  529 lbs/hr (combined
                                                                                L1&2) and 1.5%S.
Minorca Mine..........................              55  ..............         1.2-1.8  ........................
----------------------------------------------------------------------------------------------------------------

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is exempt from review by the Office of Management and
Budget (OMB) because it is a rule of particular applicability and only
affects four facilities.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under
the PRA. Because the FIP applies to just four facilities, the Paperwork
Reduction Act does not apply. See 5 CFR 1320.3(c).

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. In
making this determination, the impact of concern is any significant
adverse economic impact on small entities. An agency may certify that a
rule will not have a significant economic impact on a substantial
number of small entities if the rule relieves regulatory burden, has no
net burden or otherwise has a positive economic effect on the small
entities subject to the rule. EPA's rule adds additional controls to
certain sources. The Regional Haze FIP revisions that EPA is
promulgating here would impose Federal control requirements to meet the
BART requirement for NOX and SO2 emissions on
specific units at three sources in Minnesota and one in Michigan. The
net result of the FIP action is that EPA is requiring emission controls
on the indurating furnaces at four taconite furnaces and none of these
sources are owned by small entities, and therefore are not small
entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications as specified in
Executive Order 13175. It will not have substantial direct effects on
tribal governments. Thus, Executive Order 13175 does not apply to this
rule. However, EPA did discuss this action on a number of occasions,
including a June 28, 2015, conference call with the Michigan and
Minnesota tribes.

G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is
not economically significant as defined in Executive Order 12866, and
because EPA does not believe the environmental health or safety risks
addressed by this action present a disproportionate risk to children.
However, to the extent this rule will limit emissions of NOX
and SO2, the rule will have a beneficial effect on
children's health by reducing air pollution.

H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use

    This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    EPA believes the human health or environmental risk addressed by
this action will not have potential disproportionately high and adverse
human health or environmental effects on minority, low-income or
indigenous populations. We have determined that this rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it increases the
level of environmental protection for all affected populations without
having any disproportionately high and adverse human health or
environmental effects on any population, including any minority or low-
income population.

K. Congressional Review Act (CRA)

    This rule is exempt from the CRA because it is a rule of particular
applicability.

L. Judicial Review

    Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by June 13, 2016. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this action for the purposes of judicial review nor
does it extend the time within which a petition for judicial review may
be filed, and shall not postpone the effectiveness of such rule or
action. This action may not be challenged later in proceedings to
enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Reporting and recordkeeping requirements, Sulfur oxides,
Regional haze, Volatile organic compounds.

    Dated: March 18, 2016.
Gina McCarthy,
Administrator.
    For the reasons stated in the preamble, 40 CFR chapter I is amended
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

0
2. Section 52.1183 is amended by revising paragraphs (k), (l), (m), and
(n) and adding paragraph (p) to read as follows:

Sec.  52.1183  Visibility protection.

* * * * *
    (k) Tilden Mining Company, or any subsequent owner/operator of the
Tilden Mining Company facility in Ishpeming, Michigan, shall meet the
following requirements:
    (1) NOX Emission Limits. (i) An emission limit of 2.8 lbs
NOX/MMBTU, based on a 720-hour rolling average, shall apply
to Tilden Grate Kiln Line 1 when burning natural gas, and an emission
limit of 1.5 lbs NOX/MMBTU, based on a 720-hour rolling
average, shall apply to Tilden Grate Kiln Line 1 when burning coal or a
mixture of coal and natural gas. These emission limits will become
enforceable 60 months after May 12, 2016 and only after EPA's
confirmation or modification of the emission limit in accordance with
the procedures set forth in paragraphs (k)(1)(ii) through (viii) of
this section.
    (ii) Compliance with these emission limits shall be demonstrated
with data collected by a continuous emissions monitoring system (CEMS)
for NOX. The owner or operator must start collecting CEMS
data for NOX upon May 12, 2016 and submit the data to EPA no
later than 30 days from the end of each calendar quarter. Any remaining
data through the end of the 57th month from May 12, 2016, that does not
fall within a calendar quarter, must be submitted to EPA no later than
30 days from the end of the 57th month. Although CEMS data must
continue to be collected, it does

not need to be submitted to EPA starting 57 months after May 12, 2016.
    (iii) No later than 48 months from May 12, 2016, the owner or
operator must submit to EPA a report, including any final report(s)
completed by the selected NOX reduction technology supplier
and furnace retrofit engineer, containing a detailed engineering
analysis and modeling of the NOX reduction control
technology being installed on Tilden Grate Kiln Line 1. This report
must include a list of all variables that can reasonably be expected to
have an impact on NOX emission control technology
performance, as well as a description of how these variables can be
adjusted to reduce NOX emissions to meet the NOX
design emission limit. This NOX reduction control technology
must be designed to meet emission limits of 2.8 lbs NOX/
MMBTU when burning natural gas and 1.5 lbs NOX/MMBTU when
burning coal or a mixture of coal and natural gas.
    (iv) The NOX reduction control technology shall be
installed on Tilden Grate Kiln Line 1 furnace no later than 50 months
from May 12, 2016.
    (v) Commencing on the earlier of: Six months from the installation
of the NOX reduction control technology or 50 months from
May 12, 2016, the owner or operator must provide to EPA the results
from pellet quality analyses. The owner or operator shall provide the
results from pellet quality analyses no later than 30 days from the end
of each calendar quarter up until 57 months after May 12, 2016. Any
remaining results through the end of the 57th month that do not fall
within a calendar quarter must be submitted to EPA no later than 30
days from the end of the 57th month. The pellet quality analyses shall
include results for the following factors: Compression, reducibility,
before tumble, after tumble, and low temperature disintegration. For
each of the pellet quality analysis factors the owner or operator must
explain the pellet quality analysis factor as well as the defined
acceptable range for each factor using the applicable product quality
standards based upon customers' pellet specifications that are
contained in Tilden's ISO 9001 quality management system. The owner or
operator shall provide pellet quality analysis testing results that
state the date and time of the analysis and, in order to define the
time period when pellets were produced outside of the defined
acceptable range for the pellet quality factors listed, provide copies
of the production logs that document the starting and ending times for
such periods. The owner or operator shall provide an explanation of
causes for pellet samples that fail to meet the acceptable range for
any pellet quality analysis factor. Pellet quality information and data
may be submitted to EPA as Confidential Business Information.
    (vi) No later than 57 months after May 12, 2016, the owner or
operator may submit to EPA a report to either confirm or modify the
NOX limits for Tilden Grate Kiln Line 1 within the upper and
lower bounds described below. EPA will review the report and either
confirm or modify the NOX limits. If the CEMS data collected
during operating periods between months 50 and 57 that both meet pellet
quality specifications and proper furnace/burner operation is normally
distributed, the limit adjustment determination shall be based on the
appropriate (depending upon whether data are statistically independent
or dependent) 95% upper predictive limit (UPL) equations in paragraph
(p) of this section. If the CEMS data collected during operating
periods between months 50 and 57 that both meet pellet quality
specifications and proper furnace/burner operation are not normally
distributed, the limit adjustment determination shall be based on the
non-parametric equation provided in paragraph (p) of this section. The
data set for the determination shall exclude periods when pellet
quality did not fall within the defined acceptable ranges of the pellet
quality factors identified pursuant to paragraph (k)(1)(v) of this
section and for any subsequent period when production had been reduced
in response to pellet quality concerns consistent with Tilden's ISO
9001 operating standards. Any excluded period will commence at the time
documented on the production log demonstrating pellet quality did not
fall within the defined acceptable range and shall end when pellet
quality within the defined acceptable range has been re-established at
planned production levels, which will be presumed to be the level that
existed immediately prior to the reduction in production due to pellet
quality concerns. EPA may also exclude data where operations are
inconsistent with the reported design parameters of the NOX
reduction control technology that were installed.
    (vii) EPA will take final agency action by publishing its final
confirmation or modification of the NOX limits in the
Federal Register no later than 60 months after May 12, 2016. The
confirmed or modified NOX limit for Tilden Grate Kiln Line 1
when burning only natural gas may be no lower than 2.8 lbs
NOX/MMBTU, based on a 720-hour rolling average, and may not
exceed 3.0 lbs NOX/MMBTU, based on a 720-hour rolling
average. The confirmed or modified NOX limit for Tilden
Grate Kiln Line 1 when burning coal or a mixture of coal and natural
gas may be no lower than 1.5 lbs NOX/MMBTU, based on a 720-
hour rolling average, and may not exceed 2.5 lbs NOX/MMBTU,
based on a 720-hour rolling average.
    (viii) If the owner or operator submits a report proposing a single
NOX limit for all fuels, EPA may approve the proposed
NOX limit for all fuels based on a 30-day rolling average.
The confirmed or modified limit will be established and enforceable
within 60 months from May 12, 2016.
    (2) SO2 Emission Limits. A fuel sulfur content limit of no greater
than 1.20 percent sulfur content by weight shall apply to fuel
combusted in Process Boiler #1 (EUBOILER1) and Process Boiler #2
(EUBOILER2) beginning three months from March 8, 2013. A fuel sulfur
content limit of no greater than 1.50 percent sulfur content by weight
shall apply to fuel combusted in the Line 1 Dryer (EUDRYER1) beginning
3 months from March 8, 2013. The sampling and calculation methodology
for determining the sulfur content of fuel must be described in the
monitoring plan required at paragraph (n)(8)(x) of this section.
    (3) The owner or operator of the Tilden Grate Kiln Line 1 furnace
shall meet an emission limit of 500 lbs SO2/hr based on a
30-day rolling average beginning six months after May 12, 2016.
Compliance with these emission limits shall be demonstrated with data
collected by a continuous emissions monitoring system (CEMS) for
SO2. The owner or operator must start collecting CEMS data
for SO2 beginning six months after May 12, 2016 and submit
the data to EPA no later than 30 days from the end of each calendar
quarter. The Tilden Grate Kiln Line 1 furnace shall not be limited to
natural gas fuel. Beginning six months after May 12, 2016, any coal
burned on Tilden Grate Kiln Line 1 shall have no more than 0.60 percent
sulfur by weight based on a monthly block average. The sampling and
calculation methodology for determining the sulfur content of coal must
be described in the monitoring plan required for this furnace. The
owner or operator must calculate an SO2 limit based on 12
continuous months of CEMS emissions data and submit such limit,
calculations, and CEMS data to EPA no later than 36 months after May
12, 2016. If the submitted CEMS SO2 hourly data are normally
distributed, the SO2 lbs/hr emission rate shall be

based on the appropriate (depending upon whether data are statistically
independent or dependent) 99% upper predictive limit (UPL) equation. If
the submitted CEMS SO2 hourly data are not normally
distributed, the SO2 lbs/hr emission rate shall be based on
the non-parametric equation provided in paragraph (p) of this section.
Compliance with the SO2 lbs/hr emission rate shall be
determined on a 30-day rolling average basis. EPA will take final
agency action by publishing a confirmation or modification of the
SO2 limit in the Federal Register no later than 39 months
after May 12, 2016. EPA may adjust the 500 lbs SO2/hr limit
downward to reflect the calculated SO2 emission rate;
however, EPA will not increase the SO2 limit above 500 lbs
SO2/hr.
    (4) Starting 26 months from May 12, 2016, records shall be kept for
any day during which fuel oil is burned as fuel (either alone or
blended with other fuels) in Grate Kiln Line 1. These records must
include, at a minimum, the gallons of fuel oil burned per hour, the
sulfur content of the fuel oil, and the SO2 emissions in
pounds per hour.
    (5) Starting 26 months from May 12, 2016, the SO2 limit
for Grate Kiln Line 1 does not apply for any hour in which it is
documented that there is a natural gas curtailment beyond Cliffs'
control necessitating that the supply of natural gas to Tilden's Line 1
indurating furnace is restricted or eliminated. Records must be kept of
the cause of the curtailment and duration of such curtailment. During
such curtailment, the use of backup coal is restricted to coal with no
greater than 0.60 percent sulfur by weight.
    (l) Testing and monitoring. (1) The owner or operator shall
install, certify, calibrate, maintain, and operate a CEMS for
NOX on Tilden Grate Kiln Line 1. Compliance with the
emission limits for NOX shall be determined using data from
the CEMS.
    (2) The owner or operator shall install, certify, calibrate,
maintain, and operate a CEMS for SO2 on Tilden Grate Kiln
Line 1. Compliance with the emission standard selected for
SO2 shall be determined using data from the CEMS.
    (3) The owner or operator shall install, certify, calibrate,
maintain, and operate one or more continuous diluent monitor(s)
(O2 or CO2) and continuous flow rate monitor(s)
on Tilden Grate Kiln Line 1 to allow conversion of the NOX
and SO2 concentrations to units of the standard (lbs/MMBTU
and lbs/hr, respectively) unless a demonstration is made that a diluent
monitor and continuous flow rate monitor are not needed for the owner
or operator to demonstrate compliance with applicable emission limits
in units of the standards.
    (4) For purposes of this section, all CEMS required by this section
must meet the requirements of paragraphs (l)(4)(i) through (xiv) of
this section.
    (i) All CEMS must be installed, certified, calibrated, maintained,
and operated in accordance with 40 CFR part 60, appendix B, Performance
Specification 2 (PS-2) and appendix F, Procedure 1.
    (ii) All CEMS associated with monitoring NOX (including
the NOX monitor and necessary diluent and flow rate
monitors) must be installed and operational upon May 12, 2016. All CEMS
associated with monitoring SO2 must be installed and
operational no later than six months after May 12, 2016. Verification
of the CEMS operational status shall, as a minimum, include completion
of the manufacturer's written requirements or recommendations for
installation, operation, and calibration of the devices.
    (iii) The owner or operator must conduct a performance evaluation
of each CEMS in accordance with 40 CFR part 60, appendix B, PS-2. The
performance evaluations must be completed no later than 60 days after
the respective CEMS installation.
    (iv) The owner or operator of each CEMS must conduct periodic
Quality Assurance, Quality Control (QA/QC) checks of each CEMS in
accordance with 40 CFR part 60, appendix F, Procedure 1. The first CEMS
accuracy test will be a relative accuracy test audit (RATA) and must be
completed no later than 60 days after the respective CEMS installation.
    (v) The owner or operator of each CEMS must furnish the Regional
Administrator two, or upon request, more copies of a written report of
the results of each performance evaluation and QA/QC check within 60
days of completion.
    (vi) The owner or operator of each CEMS must check, record, and
quantify the zero and span calibration drifts at least once daily
(every 24 hours) in accordance with 40 CFR part 60, appendix F,
Procedure 1, Section 4.
    (vii) Except for CEMS breakdowns, repairs, calibration checks, and
zero and span adjustments, all CEMS required by this section shall be
in continuous operation during all periods of process operation of the
indurating furnaces, including periods of process unit startup,
shutdown, and malfunction.
    (viii) All CEMS required by this section must meet the minimum data
requirements at paragraphs (l)(4)(viii)(A) through (C) of this section.
    (A) Complete a minimum of one cycle of operation (sampling,
analyzing, and data recording) for each successive 15-minute quadrant
of an hour.
    (B) Sample, analyze, and record emissions data for all periods of
process operation except as described in paragraph (l)(4)(viii)(C) of
this section.
    (C) When emission data from CEMS are not available due to
continuous monitoring system breakdowns, repairs, calibration checks,
or zero and span adjustments, emission data must be obtained using
other monitoring systems or emission estimation methods approved by the
EPA. The other monitoring systems or emission estimation methods to be
used must be incorporated into the monitoring plan required by this
section and provide information such that emissions data are available
for a minimum of 18 hours in each 24-hour period and at least 22 out of
30 successive unit operating days.
    (ix) Owners or operators of each CEMS required by this section must
reduce all data to 1-hour averages. Hourly averages shall be computed
using all valid data obtained within the hour but no less than one data
point in each 15-minute quadrant of an hour. Notwithstanding this
requirement, an hourly average may be computed from at least two data
points separated by a minimum of 15 minutes (where the unit operates
for more than one quadrant in an hour) if data are unavailable as a
result of performance of calibration, quality assurance, preventive
maintenance activities, or backups of data from data acquisition and
handling systems and recertification events.
    (x) The 30-day rolling average emission rate determined from data
derived from the CEMS required by this section (in lbs/MMBTU or lbs/hr
depending on the emission standard selected) must be calculated in
accordance with paragraphs (l)(4)(x)(A) through (F) of this section.
    (A) Sum the total pounds of the pollutant in question emitted from
the unit during an operating day and the previous 29 operating days.
    (B) Sum the total heat input to the unit (in MMBTU) or the total
actual hours of operation (in hours) during an operating day and the
previous 29 operating days.
    (C) Divide the total number of pounds of the pollutant in question
emitted during the 30 operating days by the total heat input (or actual
hours of operation depending on the emission limit selected) during the
30 operating days.
    (D) For purposes of this calculation, an operating day is any day
during

which fuel is combusted in the BART affected unit regardless of whether
pellets are produced. Actual hours of operation are the total hours a
unit is firing fuel regardless of whether a complete 24-hour
operational cycle occurs (i.e., if the furnace is firing fuel for only
five hours during a 24-hour period, then the actual operating hours for
that day are five. Similarly, total number of pounds of the pollutant
in question for that day is determined only from the CEMS data for the
five hours during which fuel is combusted.)
    (E) If the owner or operator of the CEMS required by this section
uses an alternative method to determine 30-day rolling averages, that
method must be described in detail in the monitoring plan required by
this section. The alternative method will only be applicable if the
final monitoring plan and the alternative method are approved by EPA.
    (F) A new 30-day rolling average emission rate must be calculated
for the period ending each new operating day.
    (xi) The 720-hour rolling average emission rate determined from
data derived from the CEMS required by this section (in lbs/MMBTU) must
be calculated in accordance with paragraphs (l)(4)(xi)(A) through (C)
of this section.
    (A) Sum the total pounds of NOX emitted from the unit
every hour and the previous (not necessarily consecutive) 719 hours for
which that type of fuel (either natural gas or mixed coal and natural
gas) was used.
    (B) Sum the total heat input to the unit (in MMBTU) every hour and
the previous (not necessarily consecutive) 719 hours for which that
type of fuel (either natural gas or mixed coal and natural gas) was
used.
    (C) Divide the total number of pounds of NOX emitted
during the 720 hours, as defined above, by the total heat input during
the same 720-hour period. This calculation must be done separately for
each fuel type (either for natural gas or mixed coal and natural gas).
    (xii) Data substitution must not be used for purposes of
determining compliance under this regulation.
    (xiii) All CEMS data shall be reduced and reported in units of the
applicable standard.
    (xiv) A Quality Control Program must be developed and implemented
for all CEMS required by this section in accordance with 40 CFR part
60, appendix F, Procedure 1, Section 3. The program will include, at a
minimum, written procedures and operations for calibration checks,
calibration drift adjustments, preventative maintenance, data
collection, recording and reporting, accuracy audits/procedures,
periodic performance evaluations, and a corrective action program for
malfunctioning CEMS.
    (m) Recordkeeping requirements. (1)(i) Records required by this
section must be kept in a form suitable and readily available for
expeditious review.
    (ii) Records required by this section must be kept for a minimum of
five years following the date of creation.
    (iii) Records must be kept on site for at least two years following
the date of creation and may be kept offsite, but readily accessible,
for the remaining three years.
    (2) The owner or operator of the BART affected unit must maintain
the records identified in paragraphs (m)(2)(i) through (xi) of this
section.
    (i) A copy of each notification and report developed for and
submitted to comply with this section including all documentation
supporting any initial notification or notification of compliance
status submitted, according to the requirements of this section.
    (ii) Records of the occurrence and duration of each startup,
shutdown, and malfunction of the BART affected unit, air pollution
control equipment, and CEMS required by this section.
    (iii) Records of activities taken during each startup, shutdown,
and malfunction of the BART affected unit, air pollution control
equipment, and CEMS required by this section.
    (iv) Records of the occurrence and duration of all major
maintenance conducted on the BART affected unit, air pollution control
equipment, and CEMS required by this section.
    (v) Records of each excess emission report, including all
documentation supporting the reports, dates and times when excess
emissions occurred, investigations into the causes of excess emissions,
actions taken to minimize or eliminate the excess emissions, and
preventative measures to avoid the cause of excess emissions from
occurring again.
    (vi) Records of all CEMS data including, as a minimum, the date,
location, and time of sampling or measurement, parameters sampled or
measured, and results.
    (vii) All records associated with quality assurance and quality
control activities on each CEMS as well as other records required by 40
CFR part 60, appendix F, Procedure 1 including, but not limited to, the
quality control program, audit results, and reports submitted as
required by this section.
    (viii) Records of the NOX emissions during all periods
of BART affected unit operation, including startup, shutdown, and
malfunction, in the units of the standard. The owner or operator shall
convert the monitored data into the appropriate unit of the emission
limitation using appropriate conversion factors and F-factors. F-
factors used for purposes of this section shall be documented in the
monitoring plan and developed in accordance with 40 CFR part 60,
appendix A, Method 19. The owner or operator may use an alternate
method to calculate the NOX emissions upon written approval
from EPA.
    (ix) Records of the SO2 emissions or records of the
removal efficiency (based on CEMS data), depending on the emission
standard selected, during all periods of operation, including periods
of startup, shutdown, and malfunction, in the units of the standard.
    (x) Records associated with the CEMS unit including type of CEMS,
CEMS model number, CEMS serial number, and initial certification of
each CEMS conducted in accordance with 40 CFR part 60, appendix B,
Performance Specification 2 must be kept for the life of the CEMS unit.
    (xi) Records of all periods of fuel oil usage as required in
paragraph (k)(4) of this section.
    (n) Reporting requirements. (1) All requests, reports, submittals,
notifications, and other communications to the Regional Administrator
required by this section shall be submitted, unless instructed
otherwise, to the Air and Radiation Division, U.S. Environmental
Protection Agency, Region 5 (A-18J) at 77 West Jackson Boulevard,
Chicago, Illinois 60604. References in this section to the Regional
Administrator shall mean the EPA Regional Administrator for Region 5.
    (2) The owner or operator of each BART affected unit identified in
this section and CEMS required by this section must provide to the
Regional Administrator the written notifications, reports, and plans
identified at paragraphs (n)(2)(i) through (viii) of this section. If
acceptable to both the Regional Administrator and the owner or operator
of each BART affected unit identified in this section and CEMS required
by this section the owner or operator may provide electronic
notifications, reports, and plans.
    (i) A notification of the date construction of control devices and
installation of burners required by this section commences postmarked
no later than 30 days after the commencement date.
    (ii) A notification of the date the installation of each CEMS
required by this section commences postmarked no later than 30 days
after the commencement date.

    (iii) A notification of the date the construction of control
devices and installation of burners required by this section is
complete postmarked no later than 30 days after the completion date.
    (iv) A notification of the date the installation of each CEMS
required by this section is complete postmarked no later than 30 days
after the completion date.
    (v) A notification of the date control devices and burners
installed by this section startup postmarked no later than 30 days
after the startup date.
    (vi) A notification of the date CEMS required by this section
postmarked no later than 30 days after the startup date.
    (vii) A notification of the date upon which the initial CEMS
performance evaluations are planned. This notification must be
submitted at least 60 days before the performance evaluation is
scheduled to begin.
    (viii) A notification of initial compliance signed by the
responsible official, who shall certify its accuracy, attesting to
whether the source has complied with the requirements of this section,
including, but not limited to, applicable emission standards, control
device and burner installations, and CEMS installation and
certification. This notification must be submitted before the close of
business on the 60th calendar day following the completion of the
compliance demonstration and must include, at a minimum, the
information in paragraphs (n)(2)(viii)(A) through (F) of this section.
    (A) The methods used to determine compliance.
    (B) The results of any CEMS performance evaluations and other
monitoring procedures or methods that were conducted.
    (C) The methods that will be used for determining continuing
compliance, including a description of monitoring and reporting
requirements and test methods.
    (D) The type and quantity of air pollutants emitted by the source,
reported in units of the standard.
    (E) A description of the air pollution control equipment and
burners installed as required by this section for each emission point.
    (F) A statement by the owner or operator as to whether the source
has complied with the relevant standards and other requirements.
    (3) The owner or operator must develop and implement a written
startup, shutdown, and malfunction plan for NOX and
SO2. The plan must include, at a minimum, procedures for
operating and maintaining the source during periods of startup,
shutdown, and malfunction and a program of corrective action for a
malfunctioning process and air pollution control and monitoring
equipment used to comply with the relevant standard. The plan must
ensure that, at all times, the owner or operator operates and maintains
each affected source, including associated air pollution control and
monitoring equipment, in a manner which satisfies the general duty to
minimize or eliminate emissions using good air pollution control
practices. The plan must ensure that owners or operators are prepared
to correct malfunctions as soon as practicable after their occurrence.
    (4) The written reports of the results of each performance
evaluation and QA/QC check in accordance with and as required in
paragraph (l)(4)(v) of this section.
    (5) Compliance reports. The owner or operator of each BART affected
unit must submit semiannual compliance reports. The semiannual
compliance reports must be submitted in accordance with paragraphs
(n)(5)(i) through (iv) of this section, unless the Regional
Administrator has approved a different schedule.
    (i) The first compliance report must cover the period beginning on
the compliance date that is specified for the affected source through
June 30 or December 31, whichever date comes first after the compliance
date that is specified for the affected source.
    (ii) The first compliance report must be postmarked no later than
30 calendar days after the reporting period covered by that report
(July 30 or January 30), whichever comes first.
    (iii) Each subsequent compliance report must cover the semiannual
reporting period from January 1 through June 30 or the semiannual
reporting period from July 1 through December 31.
    (iv) Each subsequent compliance report must be postmarked no later
than 30 calendar days after the reporting period covered by that report
(July 30 or January 30).
    (6) Compliance report contents. Each compliance report must include
the information in paragraphs (n)(6)(i) through (vi) of this section.
    (i) Company name and address.
    (ii) Statement by a responsible official, with the official's name,
title, and signature, certifying the truth, accuracy, and completeness
of the content of the report.
    (iii) Date of report and beginning and ending dates of the
reporting period.
    (iv) Identification of the process unit, control devices, and CEMS
covered by the compliance report.
    (v) A record of each period of a startup, shutdown, or malfunction
during the reporting period and a description of the actions the owner
or operator took to minimize or eliminate emissions arising as a result
of the startup, shutdown, or malfunction and whether those actions were
or were not consistent with the source's startup, shutdown, and
malfunction plan.
    (vi) A statement identifying whether there were or were not any
deviations from the requirements of this section during the reporting
period. If there were deviations from the requirements of this section
during the reporting period, then the compliance report must describe
in detail the deviations which occurred, the causes of the deviations,
actions taken to address the deviations, and procedures put in place to
avoid such deviations in the future. If there were no deviations from
the requirements of this section during the reporting period, then the
compliance report must include a statement that there were no
deviations. For purposes of this section, deviations include, but are
not limited to, emissions in excess of applicable emission standards
established by this section, failure to continuously operate an air
pollution control device in accordance with operating requirements
designed to assure compliance with emission standards, failure to
continuously operate CEMS required by this section, and failure to
maintain records or submit reports required by this section.
    (7) Each owner or operator of a CEMS required by this section must
submit quarterly excess emissions and monitoring system performance
reports to the Regional Administrator for each pollutant monitored for
each BART affected unit monitored. All reports must be postmarked by
the 30th day following the end of each 3-month period of a calendar
year (January-March, April-June, July-September, October-December) and
must include, at a minimum, the requirements of paragraphs (n)(7)(i)
through (xv) of this section.
    (i) Company name and address.
    (ii) Identification and description of the process unit being
monitored.
    (iii) The dates covered by the reporting period.
    (iv) Total source operating hours for the reporting period.
    (v) Monitor manufacturer, monitor model number, and monitor serial
number.
    (vi) Pollutant monitored.
    (vii) Emission limitation for the monitored pollutant.
    (viii) Date of latest CEMS certification or audit.

    (ix) A description of any changes in continuous monitoring systems,
processes, or controls since the last reporting period.
    (x) A table summarizing the total duration of excess emissions, as
defined in paragraphs (n)(7)(x)(A) through (B) of this section, for the
reporting period broken down by the cause of those excess emissions
(startup/shutdown, control equipment problems, process problems, other
known causes, unknown causes), and the total percent of excess
emissions (for all causes) for the reporting period calculated as
described in paragraph (n)(7)(x)(C) of this section.
    (A) For purposes of this section, an excess emission is defined as
any 30-day or 720-hour rolling average period, including periods of
startup, shutdown, and malfunction, during which the 30-day or 720-hour
(as appropriate) rolling average emissions of either regulated
pollutant (SO2 and NOX), as measured by a CEMS,
exceeds the applicable emission standards in this section.
    (B)(1) For purposes of this section, if a facility calculates a 30-
day rolling average emission rate in accordance with this section which
exceeds the applicable emission standards of this section, then it will
be considered 30 days of excess emissions. If the following 30-day
rolling average emission rate is calculated and found to exceed the
applicable emission standards of this section as well, then it will add
one more day to the total days of excess emissions (i.e. 31 days).
Similarly, if an excess emission is calculated for a 30-day rolling
average period and no additional excess emissions are calculated until
15 days after the first, then that new excess emission will add 15 days
to the total days of excess emissions (i.e. 30 + 15 = 45). For purposes
of this section, if an excess emission is calculated for any period of
time within a reporting period, there will be no fewer than 30 days of
excess emissions but there should be no more than 121 days of excess
emissions for a reporting period.
    (2) For purposes of this section, if a facility calculates a 720-
hour rolling average emission rate in accordance with this section
which exceeds the applicable emission standards of this section, then
it will be considered 30 days of excess emissions. If the 24th
following 720-hour rolling average emission rate is calculated and
found to exceed the applicable emission standards of the rule as well,
then it will add one more day to the total days of excess emissions
(i.e. 31 days). Similarly, if an excess emission is calculated for a
720-hour rolling average period and no additional excess emissions are
calculated until 360 hours after the first, then that new excess
emission will add 15 days to the total days of excess emissions (i.e.
30+15 = 45). For purposes of this section, if an excess emission is
calculated for any period of time with a reporting period, there will
be no fewer than 30 days of excess emissions but there should be no
more than 121 days of excess emissions for a reporting period.
    (C) For purposes of this section, the total percent of excess
emissions will be determined by summing all periods of excess emissions
(in days) for the reporting period, dividing that number by the total
BART affected unit operating days for the reporting period, and then
multiplying by 100 to get the total percent of excess emissions for the
reporting period. An operating day, as defined previously, is any day
during which fuel is fired in the BART affected unit for any period of
time. Because of the possible overlap of 30-day rolling average excess
emissions across quarters, there are some situations where the total
percent of excess emissions could exceed 100 percent. This extreme
situation would only result from serious excess emissions problems
where excess emissions occur for nearly every day during a reporting
period.
    (xi) A table summarizing the total duration of monitor downtime, as
defined in paragraph (n)(7)(xi)(A) of this section, for the reporting
period broken down by the cause of the monitor downtime (monitor
equipment malfunctions, non-monitor equipment malfunctions, quality
assurance calibration, other known causes, unknown causes), and the
total percent of monitor downtime (for all causes) for the reporting
period calculated as described in paragraph (n)(7)(xi)(B) of this
section.
    (A) For purposes of this section, monitor downtime is defined as
any period of time (in hours) during which the required monitoring
system was not measuring emissions from the BART affected unit. This
includes any period of CEMS QA/QC, daily zero and span checks, and
similar activities.
    (B) For purposes of this section, the total percent of monitor
downtime will be determined by summing all periods of monitor downtime
(in hours) for the reporting period, dividing that number by the total
number of BART affected unit operating hours for the reporting period,
and then multiplying by 100 to get the total percent of excess
emissions for the reporting period.
    (xii) A table which identifies each period of excess emissions for
the reporting period and includes, at a minimum, the information in
paragraphs (n)(7)(xii)(A) through (F) of this section.
    (A) The date of each excess emission.
    (B) The beginning and end time of each excess emission.
    (C) The pollutant for which an excess emission occurred.
    (D) The magnitude of the excess emission.
    (E) The cause of the excess emission.
    (F) The corrective action taken or preventative measures adopted to
minimize or eliminate the excess emissions and prevent such excess
emission from occurring again.
    (xiii) A table which identifies each period of monitor downtime for
the reporting period and includes, at a minimum, the information in
paragraphs (n)(7)(xiii)(A) through (D) of this section.
    (A) The date of each period of monitor downtime.
    (B) The beginning and end time of each period of monitor downtime.
    (C) The cause of the period of monitor downtime.
    (D) The corrective action taken or preventative measures adopted
for system repairs or adjustments to minimize or eliminate monitor
downtime and prevent such downtime from occurring again.
    (xiv) If there were no periods of excess emissions during the
reporting period, then the excess emission report must include a
statement which says there were no periods of excess emissions during
this reporting period.
    (xv) If there were no periods of monitor downtime, except for daily
zero and span checks, during the reporting period, then the excess
emission report must include a statement which says there were no
periods of monitor downtime during this reporting period except for the
daily zero and span checks.
    (8) The owner or operator of each CEMS required by this section
must develop and submit for review and approval by the Regional
Administrator a site specific monitoring plan. The purpose of this
monitoring plan is to establish procedures and practices which will be
implemented by the owner or operator in its effort to comply with the
monitoring, recordkeeping, and reporting requirements of this section.
The monitoring plan must include, at a minimum, the information in
paragraphs (n)(8)(i) through (x) of this section.
    (i) Site specific information including the company name, address,
and contact information.
    (ii) The objectives of the monitoring program implemented and
information

describing how those objectives will be met.
    (iii) Information on any emission factors used in conjunction with
the CEMS required by this section to calculate emission rates and a
description of how those emission factors were determined.
    (iv) A description of methods to be used to calculate emission
rates when CEMS data are not available due to downtime associated with
QA/QC events.
    (v) A description of the QA/QC program to be implemented by the
owner or operator of CEMS required by this section. This can be the QA/
QC program developed in accordance with 40 CFR part 60, appendix F,
Procedure 1, Section 3.
    (vi) A list of spare parts for CEMS maintained on site for system
maintenance and repairs.
    (vii) A description of the procedures to be used to calculate 30-
day rolling averages and 720-hour rolling averages and example
calculations which show the algorithms used by the CEMS to calculate
30-day rolling averages and 720-hour rolling averages.
    (viii) A sample of the document to be used for the quarterly excess
emission reports required by this section.
    (ix) A description of the procedures to be implemented to
investigate root causes of excess emissions and monitor downtime and
the proposed corrective actions to address potential root causes of
excess emissions and monitor downtime.
    (x) A description of the sampling and calculation methodology for
determining the percent sulfur by weight as a monthly block average for
coal used during that month.
    (p) Equations for establishing the upper predictive limit--(1)
Equation for normal distribution and statistically independent data.
[GRAPHIC] [TIFF OMITTED] TR12AP16.000

Where:

x = average or mean of hourly test run data;
t[(n-1),(0.95)] = t score, the one-tailed t
value of the Student's t distribution for a specific degree of
freedom (n-1) and a confidence level (0.95; 0.99 for Tilden
SO2)
s\2\ = variance of the hourly data set;
n = number of values (e.g. 5,760 if 8 months of valid lbs
NOX/MMBTU hourly values)
m = number of values used to calculate the test average (m = 720 as
per averaging time)

    (i) To determine if statistically independent, use the Rank von
Neumann Test on p. 137 of data Quality Assessment: Statistical Methods
for Practitioners EPA QA/G-9S.
    (ii) Alternative to Rank von Neumann test to determine if data are
dependent, data are dependent if t test value is greater than t
critical value, where:
[GRAPHIC] [TIFF OMITTED] TR12AP16.001

[rho] = correlation between data points
t critical = t[(n-2),(0.95)] = t score, the
two-tailed t value of the Student's t distribution for a specific
degree of freedom (n-2) and a confidence level (0.95)

    (iii) The Anderson-Darling normality test is used to establish
whether the data are normally distributed. That is, a distribution is
considered to be normally distributed when p > 0.05.
    (2) Non-parametric equation for data not normally distributed and
normally distributed but not statistically independent.

m = (n + 1) * [alpha]

m = the rank of the ordered data point, when data are sorted
smallest to largest. The data points are 720-hour averages for
establishing NOX limits.
n = number of data points (e.g., 5040 720-hourly averages for eight
months of valid NOX lbs/MMBTU values)
[alpha] = 0.95, to reflect the 95th percentile

    If m is a whole number, then the limit, UPL, shall be computed as:

UPL = Xm

Where:

Xm = value of the m\th\ data point in terms of lbs SO2/hr
or lbs NOX/MMBTU, when the data are sorted smallest to
largest.

    If m is not a whole number, the limit shall be computed by linear
interpolation according to the following equation.

UPL = xm = xmi[middot]md = xmi + 0.md (xmi+1-xmi)

Where:

mi = the integer portion of m, i.e., m truncated at zero decimal
places, and
md = the decimal portion of m

0
3. Section 52.1235 is amended by revising paragraphs (b)(1)(ii),
(b)(1)(iv), (b)(1)(v), (b)(2)(iv), (c), (d), and (e) and by adding
paragraph (f) to read as follows:

Sec.  52.1235  Regional haze.

* * * * *
    (b)
    (1) * * *
    (ii) Hibbing Taconite Company--(A) Hibbing Line 1. (1) An emission
limit of 1.2 lbs NOX/MMBTU, based on a 30-day rolling
average, shall apply to Hibbing Line 1 when burning natural gas. This
emission limit will become enforceable 37 months after May 12, 2016 and
only after EPA's confirmation or modification of the emission limit in
accordance with the procedures set forth in paragraphs (b)(1)(ii)(A)(2)
through (7) of this section.
    (2) Compliance with this emission limit will be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NOX. The owner or operator of Hibbing Line 1 must install a
CEMS for NOX and SO2 within six months from May
12, 2016. The owner or operator must start collecting CEMS data and
submit the data to EPA no later than 30 days from the end of each
calendar quarter after that installation deadline. Any remaining data
through the end of the 34th month from May 12, 2016, that does not fall
within a calendar quarter, must be submitted to EPA no later than 30
days from the end of the 34th month. Although CEMS data must continue
to be collected, it does not need to be submitted to EPA starting 34
months after May 12, 2016.
    (3) No later than 24 months after May 12, 2016 the owner or
operator must submit to EPA a report, including any final report(s)
completed by the selected NOX reduction technology supplier
and furnace retrofit engineer, containing a detailed engineering
analysis and modeling of the NOX reduction control
technology being installed on Hibbing Line 1. The NOX
reduction control technology must be designed to meet an emission limit
of 1.2 lbs NOX/MMBTU. This report must include a list of all
process and control technology variables that can reasonably be
expected to have an impact on NOX emissions control
technology performance, as well as a description of how these variables
can be adjusted to reduce NOX emissions to meet the
NOX design emission limit.
    (4) The NOX reduction control technology shall be
installed on Hibbing Line 1 furnace no later than 26 months after May
12, 2016.
    (5) Commencing on the earlier of: Six months from the installation
of the NOX reduction control technology; or 26 months from
May 12, 2016, the owner or operator must provide to EPA the results
from pellet quality analyses. The owner or operator shall provide the
results from pellet quality analyses no later than 30 days from the end
of each calendar quarter up until 34 months after May 12, 2016. Any
remaining results through the end of the 34th month from May 12, 2016,
that do not fall within a calendar quarter, must be submitted to EPA no
later than 30 days from the end of the 34th month. The

pellet quality analyses shall include results for the following
factors: Compression, reducibility, before tumble, after tumble, low
temperature disintegration, and swelling. For each of the pellet
quality analysis factors, the owner or operator must explain the pellet
quality analysis factor, as well as the defined acceptable range for
each factor using the applicable product quality standards based upon
customers' pellet specifications that are contained in Hibbing's ISO
9001 quality management system. The owner or operator shall provide
pellet quality analysis testing results that state the date and time of
the analysis and, in order to define the time period when pellets were
produced outside of the defined acceptable range for the pellet quality
factors listed, provide copies of the production logs that document the
starting and ending times for such periods. The owner or operator shall
provide an explanation of causes for pellet samples that fail to meet
the acceptable range for any pellet quality analysis factor. Pellet
quality information and data may be submitted to EPA as Confidential
Business Information.
    (6) No later than 34 months after May 12, 2016, the owner or
operator may submit to EPA a report to either confirm or modify the
NOX limits for Hibbing Line 1 furnace within the upper and
lower bounds described below. EPA will review the report and either
confirm or modify the NOX limits. If the CEMS data collected
during operating periods between months 26 and 34 that both meet pellet
quality specifications and proper furnace/burner operation is normally
distributed, the limit adjustment determination shall be based on the
appropriate (depending upon whether data are statistically independent
or dependent) 95% upper predictive limit (UPL) equations in paragraph
(f) of this section. If the CEMS data collected during operating
periods between months 26 and 34 that both meet pellet quality
specifications and proper furnace/burner operation are not normally
distributed, the limit adjustment determination shall be based on the
non-parametric equation provided in paragraph (f) of this section. The
data set for the determination shall exclude periods when pellet
quality did not fall within the defined acceptable ranges of the pellet
quality factors identified pursuant to paragraph (b)(1)(ii)(E) of this
section and for any subsequent period when production has been reduced
in response to pellet quality concerns consistent with Hibbing's ISO
9001 operating standards. Any excluded period will commence at the time
documented on the production log demonstrating that pellet quality did
not fall within the defined acceptable range and shall end when pellet
quality within the defined acceptable range has been re-established at
planned production levels, which will be presumed to be the level that
existed immediately prior to the reduction in production due to pellet
quality concerns. EPA may also exclude data where operations are
inconsistent with the reported design parameters of the NOX
reduction control technology installed.
    (7) EPA will take final agency action by publishing its final
confirmation or modification of the NOX limit in the Federal
Register no later than 37 months after May 12, 2016. The confirmed or
modified NOX limit for Hibbing Line 1 when burning only
natural gas may be no lower than 1.2 lbs NOX/MMBTU, based on
a 30-day rolling average, and may not exceed 1.8 lbs NOX/
MMBTU, based on a 30-day rolling average.
    (B) Hibbing Line 2. (1) An emission limit of 1.2 lbs
NOX/MMBTU, based on a 30-day rolling average, shall apply to
Hibbing Line 2 when burning natural gas. This emission limit will
become enforceable 55 months after May 12, 2016 and only after EPA's
confirmation or modification of the emission limit in accordance with
the procedures set forth in paragraphs (b)(1)(ii)(B)(2) through (7) of
this section.
    (2) Compliance with this emission limit will be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NOX. The owner or operator of Hibbing Line 2 must install a
CEMS for NOX and SO2 within six months from May
12, 2016. The owner or operator must start collecting CEMS data and
submit the data to EPA no later than 30 days from the end of each
calendar quarter after that installation deadline. Any remaining data
through the end of the 52nd month from May 12, 2016, that does not fall
within a calendar quarter, must be submitted to EPA no later than 30
days from the end of the 52nd month. Although CEMS data must continue
to be collected, it does not need to be submitted to EPA starting 52
months after May 12, 2016.
    (3) No later than 42 months after May 12, 2016 the owner or
operator must submit to EPA a report, including any final report(s)
completed by the selected NOX reduction technology supplier
and furnace retrofit engineer, containing a detailed engineering
analysis and modeling of the NOX reduction control
technology being installed on Hibbing Line 2. The NOX
reduction control technology must be designed to meet an emission limit
of 1.2 lbs NOX/MMBTU. This report must include a list of all
process and control technology variables that can reasonably be
expected to have an impact on NOX emissions control
technology performance, as well as a description of how these variables
can be adjusted to reduce NOX emissions to meet the
NOX design emission limit.
    (4) The NOX reduction control technology shall be
installed on Hibbing Line 2 furnace no later than 44 months after May
12, 2016.
    (5) Commencing on the earlier of: Six months from the installation
of the NOX reduction control technology; or 44 months from
May 12, 2016, the owner or operator must provide to EPA the results
from pellet quality analyses. The owner or operator shall provide the
results from pellet quality analyses no later than 30 days from the end
of each calendar quarter up until 52 months after May 12, 2016. Any
remaining results through the end of the 52nd month from May 12, 2016,
that do not fall within a calendar quarter, must be submitted to EPA no
later than 30 days from the end of the 52nd month. The pellet quality
analyses shall include results for the following factors: Compression,
reducibility, before tumble, after tumble, low temperature
disintegration, and swelling. For each of the pellet quality analysis
factors, the owner or operator must explain the pellet quality analysis
factor, as well as the defined acceptable range for each factor using
the applicable product quality standards based upon customers' pellet
specifications that are contained in Hibbing's ISO 9001 quality
management system. The owner or operator shall provide pellet quality
analysis testing results that state the date and time of the analysis
and, in order to define the time period when pellets were produced
outside of the defined acceptable range for the pellet quality factors
listed, provide copies of the production logs that document the
starting and ending times for such periods. The owner or operator shall
provide an explanation of causes for pellet samples that fail to meet
the acceptable range for any pellet quality analysis factor. Pellet
quality information and data may be submitted to EPA as Confidential
Business Information.
    (6) No later than 52 months after May 12, 2016, the owner or
operator may submit to EPA a report to either confirm or modify the
NOX limits for Hibbing Line 2 furnace within the upper and
lower bounds described below. EPA

will review the report and either confirm or modify the NOX
limits. If the CEMS data collected during operating periods between
months 44 and 52 that both meet pellet quality specifications and
proper furnace/burner operation is normally distributed, the limit
adjustment determination shall be based on the appropriate (depending
upon whether data are statistically independent or dependent) 95% upper
predictive limit (UPL) equations in paragraph (f) of this section. If
the CEMS data collected during operating periods between months 44 and
52 that both meet pellet quality specifications and proper furnace/
burner operation are not normally distributed, the limit adjustment
determination shall be based on the non-parametric equation provided in
paragraph (f) of this section. The data set for the determination shall