U

. S. Stee l C or pora tion M i n ne so t a O r e O p e rat io ns P

. O

. Box 41 7 MI. I ron. MN 55768

CERTI FIED MAIL 700 6010 00006 4747 9605
Janu ary 11 , 2010 Mr. Ch ristopher J

. Nelso n , P

. E

. M anager, Met alli c Minin g Sec tor Minn esota Pollution Co ntrol A g ency 5 20 L afayett e ro ad North Sai nt P aul, MN 55 I5 5-4 194 SU BJECT : N O , red uction s in a ccordance wi th U. S

. Stee l Co rporation

- Mi nneso ta O re Op eration s ( Minntac) PSD P ermit # 13700005-005
De ar M r . N elson : U. S

. Stee l (USS) wo uld like to thank the Minneso ta Polluti on Contro l Agency (MPCA) for taking tim e to me et with u s o n D ec ember 15 , 2 009 in regards t o the N O , requ irem ent s in Minn tac 's P SD Permit # 13700005 -0 05. T he m e eting p rovided U SS w ith additi onal inf orm ation a nd insig ht ass o ciated wit h Mi nn tac's P SD Permit N O , req ui reme nts. US S wo uld a lso l ike to take this oppo rtunity to clarify the ap pare nt misu nderstand ing co ncerni ng th e techni ca l fea sibility of s elective catalytic redu ction ( SCR) (clean-side, dirty - side and reg enera tive) technol ogies. US S co rre spond ence d ated Au gust 1 7, 2 009 a nd Nove mbe r 30, 2009 was in re f erence to clean-side a nd d irty-side S CR technologies only not the rege nerative SCR tec hno logy

. USS s ub mitte d an e ngineeri ng a nalysis report eval uating NO, reduction strategies and technologies on February 27 , 2009 as req uire d b y M inntac's PSD p er mi t, Regenerative S CR ( R SCR) was co ns idered as a type of clea n side SC R in the engineering a nalysis re port. A fter s ubmitta l of th e e ngineeri ng a nalysis re por t, U SS co nt inued to in vestigate o ther NO, c ontrol techn ologies a nd ve ndors. U SS rece ived a proposa l for a R SCR sy s tem from B abcock P ower In c. in Apri l of 2009

. Bab cock P ower gave a presentation of the ir RSC R tech nolo gy to USS represen tatives on May 27, 2009

. D ue to the lack of a pilo t test ing unit from the vendor, the eco nomic s ituation a t the tim e, a nd the c o nfiden ce of the SNC R ve ndor in the ability of th eir te chnology to b e s u ccess fully pilot tested , US S di d not pursue p ilot testin g RS CR

. Furt hermore , USS had a lready propose d , and M PCA ap proved, low NO, m ain burn er a nd SNCR pilot te sts. While the techno logy is wor thy of investi gating , U SS need s to take the ti me to eval uate ke y operating process variables a nd R SCRs compatibi lity with those va riables to d etermin e w hether or not R S CR i s te chni cally feasib le for Mi nntac 's o perating 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 of each control technology tested, and a summary of major 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 technologyforfull 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 succes sful 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 of re sources. 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 of the seriousness of this 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 ton s per year . It 

### is the position ofUSS that the goal of the permit is to meet or exceed a 70 % reduction of NO, 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 s trategies that include low NO , main burner s and process optimization improvements. If you have any question s, please do not hesitate to contact Chrissy Bartovich at (218) 749-7364

. Sincerely,

# d: :d 

# & "'--' Scott Coleman / General Manager - Minnesota Ore Operations