# ASH GROVE CEMENT COMPANY -----C**~--:-----**

WESTERN REGION 100 HWY. 516 CLANCY. MT 59634-9701 PHONE 406 I 442-6855

FAX 406 I 442·9262 May 5,2008

Ms. Callie A. Videtich, Director Air and Radiation Program United States Environmental Protection Agency Region 8 1595 Wynkoop Street Denver, Colorado 80202-1129



### RE: Ash Grove Cement

- Montana CitY Plant Response to Comments on Best Available Retrofit Technology (BART) Analysis

Dear Ms. Videtich:

Ash Grove

### Cemen~Company (Ash Grove) recently submitted responses to comments provided by the U.S.

### Enviro~meritalProtection**Ag~Dcy** (USEPA) Region 8 on the 

### BARTFive Factor 

### Analysis dated**JUD~** 2007 for ourMontana City plant. 

### In preparing the responses to comments, Ash Grove providep some infonnation on the cost ofchanging fuels that was differentthan the information**provid~d** in the original BART analysis. Ms. Kasi Dubbs ofTrinity Consultants has briefly discussed the different information with Ms. Laurel Dygowski. Ms. Dygowski requested thatAsh Grove clarify and/orrevise any information in the original BART analysis, as necessary,
so that EPA is not left to interpret what information from the original BART analysis is no longer valid. This letter identifies the infonnation that was updated by Ash Grove during the preparation ofthe responses to comments.

The original BART analysis indicated that the sulfur content ofthe existing coke used at the plant

was 4.5%. Since the submittal ofthe original BART analysis, Ash Grove has determined that the sulfur content ofthe existing coke is actually 5.2%. The original BART analysis also assumed that a 50%reduction in inlet fuel sulfur would result a 50% reduction 

### in S02 emissions. Further, the analysis assumed thatthe inlet fuel sulfur could be cut 

### by 50% by using a fuel blend that is 11 % coke and 89% coal, where the specific coal and coke assumed fortheblend are the same coal and coke that are currently burned atthe plant. Since the submittal ofthe original BART analysis, Ash Grove has determined thatthe maximum amount ofcoal that can be utilized in the fuel blend without adversely affecting the quality ofthe clinker, is a blend of38% coke and 62% coal. Further, Ash Grove concluded that a 50% reduction 

### in the inlet fuei sulfurwould Dot drop S02 emissions by 50%, since a portion ofthe S02 emissions are not generated from the sulfur in the fuel butrather are generated from the 

### sulfur in the kiln feed. The sulfur in the kiln feed cannot be changed.

## PC~ PDrll.nd CementAs>act.lI", IUIdIEIiIn responding to the EPA's comments on fuel switching, Ash Grove provided a revised cost analysis for fuel switching that considers the revised information presented above. The cost for reducing S02 based on using the existing fuels, but switching to a blend that is 38% coke and 62% coal, was detelmined to be $2,995/ton S02 removed. The revised cost infol111ation should replace the information presented in Section 4.4.2 ofthe original BART analysis.



### Ifyou have any questions concerning the infol111ation in this letter, please feel free to contact me at 406-442-8855.

Sincerely, (

.'**~.** Richard Johnson

Plant Manager-Montana City