U. S. Steel Corporation

Minnesota Ore Operations

P.O. Box 417

MI. Iron. MN 55768

CERTIFIED MAIL 700 601000006 4747 9605

January 11, 2010

Mr. Christopher J. Nelson, P.E.

Manager, Met alli c Mining Sector

Minnesota Pollution Control Agency

520 Lafayett e road North

Saint Paul, MN 55 I55-4 194

SUBJECT : NO, reductions in accordance with U. S. Stee l Corporation - Minneso ta

Ore Operations (Minntac) PSD Permit # 13700005-005

Dear Mr. Nelson:

U. S. Stee l (USS) would like to thank the Minnesota Pollution Control Agency (MPCA)

for taking time to me et with us on December 15, 2009 in regards to the NO, requ irements

in Minntac 's PSD Permit #13700005-005. The meeting provided USS with additional

information and insight associated wit h Minntac's PSD Permit NO, requirements.

USS would also like to take this opportunity to clarify the appare nt misu nderstanding

concerni ng the technica l feasibility of selective catalytic redu ction (SCR) (clean-side,

dirty-side and regenerative) technologies. US S correspondence dated August 17, 2009

and Novembe r 30, 2009 was in reference to clean-side and dirty-side SCR technologies

only not the regenerative SCR techno logy. USS submitted an engineeri ng analysis report

evaluating NO, reduction strategies and technologies on February 27, 2009 as req uire d

by Minntac's PSD permit, Regenerative SCR (RSCR) was considered as a type of clean

side SCR in the engineering analysis report. After submitta l of the engineeri ng analysis

report, USS continued to investigate other NO, control techn ologies and vendors. USS

rece ived a proposal for a RSCR system from Babcock Power Inc. in April of 2009.

Babcock Power gave a presentation of the ir RSC R technology to USS representatives on

May 27, 2009. Due to the lack of a pilot test ing unit from the vendor, the eco nomic

situation at the time, and the confidence of the SNCR vendor in the ability of their

technology to be successfully pilot tested , USS did not pursue pilot testin g RSCR.

Furthermore, USS had already proposed, and MPCA approved, low NO, main burner and

SNCR pilot tests. While the technology is worthy ofinvestigating, USS need s to take the

time to eval uate key operating process variables and RSCRs compatibility with those

variables to determine whether or not RSCR is technically feasib le for Minntac 's

operating line s.
The regenerative SCR misunderstanding between the MPCA and USS has brought to

light several intetpretation issues associated with Minntac's PSD permit, and these

include:

• The effective date associated with the 7,300 Tons/year 365-day rolling sum limit

assigned to GP009, GPOIO and GPOll, and

• The requirements for pilot testing. Specifically pilot testing in accordance with

USS submitted and MPCA approved pilot test schedules verses simultaneous pilot

testing.

7,300 Tons/yr 365-day- rolling sum Limit

During the composition of Minntac's PSD Permit #13700005-005, it was U. S. Steel's

interpretation that the 7,300 tons/yr 365-day rolling sum limit would be effective

February 1, 2010 with February l" being the first day of the rolling sum. In the facility

description, the language states, "A lower annual limit takes affect for NOx after

February 1, 2010 (7,300 ton/yr)." However, as the permit is currently written, it is stated

that "Nitrogen Oxides: less than or equal to 7300 tons/year using 365-day Rolling Sum

from all five waste gas stacks combined (GP 009 through 011; SV 103, 118, 127, 144,

and 151) no later than Feb. 1,2010,".

U. S. Steel intended to fully comply with the language from the facility description. The

facility description language allows USS to conduct pilot testing to ensure technical

feasibility of a technology without permit compliance issues. However, the permit

condition was not written in accordance with the facility description and therefore is

incorrect. U. S. Steel would like to request the MPCA to complete an Administrative

Amendment of Minntac's PSD Permit #13700005-005 to clarify that the 365-day Rolling

Sum will be in place for the annual period beginning February 1, 2010. The

administrative amendment for this issue can be done in accordance with Minnesota Rule

7007.1400 subpart I. G.

Requirements for Pilot Testing

USS submitted the engineering analysis report and pilot test schedule to the MPCA in

accordance with Minntac's PSD Permit #13700005-005 on February 27, 2009. The

MPCA acknowledged receipt of the engineering analysis Report and approved the

proposed pilot test schedule in a letter from the agency dated April 16, 2009. USS

proposed to pilot test a low NOx main butner on line 7 and SNCR on line 7. Minntac's

PSD Permit states"No more than 60 days after pilot test completion, submit Pilot Test

Results of NOr control technologies for MPCA approval. The Pilot Test Results

submittal shall include, at a minimum, a technical description ofeach control technology

tested, and a summary ofmajor physical and chemical data obtained that are important

for deciding whether or not the technology should be demonstrated With the Pilot Test

Results, the Permittee shall propose one control technology forfull scale demonstration

on one Agglomerator line and shall rank the other control technologies that have been

pilot tested for potential demonstration." USS pilot tested SNCR July through October

2009, and the technology was not successful. USS submitted the required Pilot Test

Results Report to the MPCA on December 9, 2009. USS is currently in the process of
equipment procurement to pilot test a low NO, main burner on line 7 in accordance with

the pilot test schedule submitted to the MPCA on February 27, 2009. It is USS's position

that Minntac's NO, reduction goals can be achieved by the installation of low NO, main

burners and process optimization, therefore USS would like to evaluate the results of the

low NO, main burner pilot test before pilot testing other technically feasible NO, control

technologies. This approach is in accordance with the approved pilot test schedule and

correspondence from the MPCA dated April 16,2009.

The MPCA is interested in gathering information on LoTOx and RSCR through pilot

testing at the Minntac facility. This will require simultaneous pilot testing in conjunction

with the low NO, main burner. It is USS' s position that Minntac's PSD permit does not

require simultaneous pilot testing of control technologies and further does not require all

technically feasible control technologies identified to be pilot tested. Should the low NO,

main burner pilot test be successful and prove that USS can meet or exceed its PSD

permit goals, pilot testing additional technically feasible NO, control technologies will

not be necessary and would be an inefficient use ofresources. Simultaneous pilot testing

poses a problem for USS. Pilot tests of LoTOx and/or RSCR would be conducted on

lines that are not equipped with low NO, main burners and have not undergone process

optimization improvements. Process variables associated with low NO, main burners

and process optimization improvements are key elements to evaluating LoTOx and

RSCR technologies and producing meaningful data.

USS is aware ofthe seriousness ofthis NO, PSD issue and fully intends to meet the PSD

Permit goal of installing a NO, control/reduction technology on all five indurating lines

and meet or exceed a reduction of 70% NO, from 13,300 tons per year. It is the position

ofUSS that the goal ofthe permit is to meet or exceed a 70% reduction ofNO, and not to

pilot test every technically feasible NO, control technology. Additional pilot testing will

delay the installation of a full scale demonstration on one line, and ultimately installation

on the other indurating lines. USS believes that Minntac can meet the PSD Permit goals

through NO, generation reduction technologies and strategies that include low NO, main

burners and process optimization improvements.

If you have any questions, please do not hesitate to contact Chrissy Bartovich at (218)

749-7364.

Sincerely,

d: :d & "'--'

Scott Coleman /

General Manager - Minnesota Ore Operations