MEMORANDUM
SUBJECT: Environmental Protection Agency (EPA) visit to Oldcastle's Trident cement kiln
FROM: Jaslyn Dobrahner, EPA Region 8, Air Quality Planning Unit
TO:  Docket EPA-R08-OAR-2017-0062 for Montana regional haze FIP revision
DATE: June 30, 2017

The EPA visited Oldcastle's Trident cement kiln on June 29, 2017 for a site tour. The EPA staff (Melinda Beaver, Jaslyn Dobrahner, and Aaron Worstell) were accompanied by staff from the Montana Department of Environmental Quality (MT DEQ). 
Pre-tour Meeting
Prior to commencing the tour, EPA and MT DEQ staff met with Oldcastle representatives in a meeting room in the Main Office building at 9:00 am. The EPA stated that the purpose of the visit was to learn more about Oldcastle's operations and observe the selective non-catalytic reduction (SNCR) system. During this meeting, Oldcastle presented:
 History of the Trident plant;
 Basic information on cement kiln mechanics and design;
 A schematic of the newly installed SNCR system; and
 Challenges associated with operating an SNCR system, including obtaining the optimal molar ratio and the associated potential for ammonia slip.
Oldcastle also mentioned the publication of the EPA's proposed rule (82 FR 17948) to revise the NOx emission limit at the Trident plant and subsequently inquired with EPA what the next steps of the rulemaking process were. The EPA explained that the next step of the process was to publish a final action that the agency plans be effective prior to the current compliance date of October 18, 2017 which would require signature on the final rule in late August. The EPA stated that they were on schedule to meet the August signature date.
Oldcastle mentioned the fact that many of the EPA's regional haze actions are litigated and wanted to know what the deadline was for the final action to be litigated so that they may have some more certainty about their final NOx emission limit. The EPA explained that there is a 60-day time period after publication of the final rule to submit petitions for reconsiderations and would confirm that with EPA's counsel.
During this pre-meeting there were discussions amongst Oldcastle, EPA, and MT DEQ about the operation of the SNCR system. Oldcastle explained that the SNCR system was operational for a brief time during which needed modifications were identified. When the remaining modifications are completed the system will be performance tested. During the brief time that is was operational, it reduced NOx emissions from the kiln.  

Plant Tour
After donning safety gear, EPA, MT DEQ, and Oldcastle staff started the plant tour by visiting the newly constructed ammonia reagent facility for SNCR. Oldcastle staff explained the operational design of the system, including safety and cold weather precautions in place. Next, the group climbed to the top of the rotating kiln to view the juncture between the incoming stationary air and ammonia lines with the rotating kiln (the air and ammonia injection ports are located along the rotating kiln). Oldcastle brought the tour group to the top of the limestone slurry tanks and then walked along the length of the rotating kiln to observe the ammonia injection ports. After walking the length of the kiln, the tour continued in the operations/control room of the plant followed by the milling sheds for both raw material and clinker.
Quarry Tour
At the conclusion of the plant tour, the group toured the adjacent quarry. Oldcastle staff showed the raw material stockpiles and explained differences in the purity of the limestone in the quarry and how they manage variability in the limestone raw material. Oldcastle also pointed out how they dispose of the dust by-product (which is placed near the quarry) and the dust control measures in place.
The visit concluded at 11:00 am at the Main Office building.
