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From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]

Sent: Thursday, August 21, 2014 9:05 AM

To: Putney, David; French, Chuck; David Green; Marksbe rry, James; Paulin, Nick Subject: RE: Discuss Cent Al of KY bake furnaces

• David, just 2 comments or clarifications ;

• The addition rate of unreacted alumina to the dry a lumina scrubber/baghouse system associated with the bake furnaces at this facility is similar to the ad dition rates utilized in dry alumina scrubber/bagho use systems associated with bake furnaces at other primary alum inum facilities;- The rate at which the alumina is fed to our scrubber is adequate for scrubbing our POM and TF emissions. We are not aware of what other facil ities
alumina feed rates are with their bake scrubbers.

The firing operations (e.g., natural gas fuel usage , pitch burn rate and temperature) of the bake furn aces at the Century Aluminum of KY facility are manual (as oppo sed to automatic). As far as Century Aluminum of KY facility personnel are aware, their facility is the only primary aluminum production facility whose ba ke furnaces utilize manual firing operations; and- We operate our furnaces manually. We stated that o ur facility in Sebree has an automated firing system. We do not know if we are the only facility that operates its firing s ystem manually.

Thanks

Jamie

From: Putney, David [ mailto:putney.david@epa.gov ]
Sent: Wednesday, August 20, 2014 8:22 PM
To: French, Chuck; Coomes, Jamie; David Green; Marksbe rry, James; Paulin, Nick Subject: RE: Discuss Cent Al of KY bake furnaces

Hello all,

Just a quick note to summarize our discussion of th e bake furnaces at the Century Aluminum of KY earli er today. If you notice any errors or omissions, pleas e let me know by close of business this Friday (08/ 22/14).

Summary of facts:

• Century Aluminum of KY operates 3 anode bake furnac es whose emissions are comingled and then routed through a dry alumina scrubber/baghouse syst em;

• PM emissions from the bake furnaces are tested annu ally by the same contractor. These PM emission rates have varied over the years by a factor of abo ut 7 and between the runs of a given 3 run test the y have varied by as much as an order of magnitude;

• The dry alumina scrubber/baghouse system associated with the bake furnaces at this facility is equippe d with a bag leak detection system which has not indi cated bag leaks during the test runs associated wit h the higher PM emissions rates;

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• Visible emissions observations made during the PM t ests run on dry alumina scrubber/baghouse system associated with the bake furnaces at this facility have not indicated elevated visible emissions durin g the test runs associated with the higher PM emissions rates;

• Century Aluminum of KY personnel are not aware of a ny operating conditions or throughput variations which occurred during the PM tests runs associated with the higher PM emissions rates that would expla in those higher PM emissions rates;

• The addition rate of unreacted alumina to the dry a lumina scrubber/baghouse system associated with the bake furnaces at this facility is similar to th e addition rates utilized in dry alumina scrubber/b aghouse systems associated with bake furnaces at other prim ary aluminum facilities;

• The dry alumina scrubber/baghouse system associated with the bake furnaces at this facility is essenti ally the same control system utilized to control emissio ns from bake furnaces at other primary aluminum fac ilities;

• Century Aluminum of KY facility personnel conduct a bake furnace exhaust manifold check every 4 hours to ensure the proper work practices are being imple mented and that excessive pre-control system emissi ons are not being generated;

• The firing operations (e.g., natural gas fuel usage , pitch burn rate and temperature) of the bake furn aces at the Century Aluminum of KY facility are manual ( as opposed to automatic). As far as Century Aluminu m of KY facility personnel are aware, their facility is the only primary aluminum production facility whose bake furnaces utilize manual firing operations; and

• Century Aluminum of KY facility personnel estimate that the capital costs associated with installing t he automatic bake furnace firing operations would be a round $8 million to $10 million.

Follow up items:

• Century Aluminum of KY facility personnel will prov ide EPA with electronic copies of the test reports associated with the bake furnace PM testing during 2012, 2013 and 2014;

• Century Aluminum of KY facility personnel will prov ide EPA with information on the air to cloth ratio of the dry alumina scrubber/baghouse system associated with the bake furnaces at that facility;

• Century Aluminum of KY facility personnel will disc uss the higher grain loading associated with the te st runs conducted on 06/20/12, 06/10/14, and 06/11/14 with BWF (the supplier of filter bags utilized in t he dry scrubber/baghouse system associated with the bake f urnaces at their facility) and provide EPA with a s ummary of those discussions;

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• Century Aluminum of KY facility personnel will prov ide EPA with a summary of the exhaust manifold check that they perform every 4 hours (i.e., a list of the associated work practices, etc.);

• EPA personnel will review the test reports associat ed with the bake furnace PM testing during 2012, 20 13 and 2014 in search of any explanation of the higher test runs; and

• EPA personnel will contact The Aluminum Association for information on whether or not any member companies utilize manual bake furanace firing opera tions at any of their primary aluminum production p lants.

Thanks.

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

-----Original Appointment-----

From: Putney, David

Sent: Friday, August 08, 2014 3:07 PM

To: French, Chuck; Coomes, Jamie Subject: Discuss Cent Al of KY bake furnaces
When: Wednesday, August 20, 2014 10:00 AM-11:00 AM (UTC- 05:00) Eastern Time (US & Canada).
Where: RTP-Line-541-1591/Phone-Line/RTP-Conf-Bridge

Hello all,

Let’s have a telephone conference to discuss the ba ke furnaces at the Century Aluminum of KY facility (see associated email string below). I have scheduled th e discussion for 10:00 AM eastern time (9:00 AM cen tral time) on call in line (919) 541-1591.

Please let me know if this date or time does not wo rk for you.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency

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Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]

Sent: Friday, August 08, 2014 10:51 AM

To: Putney, David Subject: RE: PM from bake furnace at Century Aluminum of KY facility

Yes I believe it would be good for us to talk throu gh what the proposed PM limit may be and what if an y progress has been made on changing the way we calcu late our emissions based on three furnaces (one new and two existing) ducted to a common control device . I know Sean Lane had sent you some information on this point.

IM available Tuesday or Wednesday of that week at 9:00 AM CST.

I will have a representative from the bake furnace operations, scrubber operations and stack testing c ompany on the call.

Thanks

Jamie

From: Putney, David [ mailto:putney.david@epa.gov ]
Sent: Friday, August 08, 2014 9:36 AM
To: Coomes, Jamie Cc: French, Chuck Subject: FW: PM from bake furnace at Century Aluminum of KY facility

Jamie,

With regards to the new (June 2014) PM emissions te st data for your bake furnaces - I assumed bake fur nace operation for 720 hours during June (24 hours per d ay for 30 days) and 13,896 tons of green anode (thi s is the average of the historical values provided in your e mail dated 05/28/14) and came up with an emissions value of 0.178 lb PM per ton of green anode for the testi ng done in June 2014. This is probably off a bit si nce I used an average green anode value as opposed to the actu al value for June 2014 – but close. So, over the la st 14 1⁄2 years the PM emissions from this source have ranged from about 0.025 lb PM per ton of green anode (May of 2009) to about 0.178 lb PM per ton of green anode ( June of 2014). That is, the highest value is about 7 times the lowest value. This is quite a bit of variabilit y, especially for a source controlled via dry alumi na scrubbers (as my records indicate).

I think we need to set up a conference call with so me personnel from your facility to discuss the bake furnaces at the Century Aluminum of KY facility. Specificall y, I would like to discuss:

## p. 5 of 5 • Whether, perhaps, some aspect of the associated ope rations would suggest that the bake furnaces at your facility should be in a separate subcategory t han those at other primary aluminum facilities;

• The representativeness (or lack thereof) of the tes ts associated with higher PM emissions from the bak e furnaces (i.e., April of 2001, April of 2007, May o f 2010, June of 2012, and June of 2014); and

• Any information Century Aluminum of KY personnel ma y have which could help explain the high variability in the PM emissions from the bake furna ces at this facility (e.g., bag failures during tes ting, new personnel operating the associated controls, etc.).

As I mentioned in my email dated 05/23/14, based on the data I currently have available, it would appe ar that the bake furnaces at the Century Aluminum of KY fac ility would have trouble consistently meeting the associated MACT floor (based on testing conducted o n bake furnaces at 7 primary aluminum facilities in 2013). It is imperative that we determine whether or not t his is indeed the case before the upcoming residual risk and technology review (RTR) amendments to the primary a luminum reduction facility NESHAP are finalized.

Would Century Aluminum of KY personnel be available for such a telephone conference some time on Tuesd ay (08/19/14) through Friday (08/22/14)? If so, please send me a list of preferred dates/times for such a conference call. If not, then please send me a list of alternative preferred dates/times for such a co nference
call.

Thanks so much.

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov