From: John Rego <jrego@JonesDay.com>

Sent: Monday, August 27, 2012 2:27 PM

To: Beth Friedman

Cc: Chin.Conrad@epamail.epa.gov; nelson.brad@ecrweb.com; Jeff.McKinney@erametgroup.com;

french.chuck@epa.gov; RLunn@fpiwv.com; lmcafee@bdlaw.com

Subject: Re: Manganese concentration assumptions

Beth:

Based on today's conference call, I understand that EPA intends to conduct the next round of revised

modeling using manganese concentrations as described in your email of August 21, 2012. Nevert heless,

since EMI agreed during the August 23, 2012 conference call to provide an explanation of how an

estimated manganese content could be calculated for emissions during tapping and casting, based on

the manganese content of the slags and metal alloy s produced by EMI, I am forwarding description of

that approach.

As a starting point, the approximate manganese content of the solid slags and ferroalloys produced by

EMI is as follows:

High Carbon Ferromanganese 78% (Upper Limit)

Silic omanganese 68% (Upper Limit)

HC Ferromanganese Slag 18% (Average)

Silicomanganese Slag 3% (Average)

Since EMI produces both HC Ferromanganese and Silicomanganese, and since Furnaces 1 and 12 at EMI

are each cap able of producing each product, EMI believes it is reasonable to base the calculation on a

50% contribution from each. Also, since the less dense slag blankets the metal during more than 75% of

the tap and post

- tap molten metal operations and thereby di sproportionately contributes to the fume

generated during such operations, it is reasonable to apportion 75% of such emissions to the slag and

25% to the product.

Thus, the estimated average Mn content would be based on 75% of the average slag content and 25% of

the average metal content, where the average slag content is 10.5% ((18 + 3)/2) and the average metal

content is 73% ((78 + 68)/2), or (0.75)(.105) + (0.2 5)(0.73) = 0.261 or 26.1%.

Please let me know if you have any questions.

John

John Rego • Environmental, Health & Safety

901 LAKESIDE AVENUE • CLEVELAND, OHIO 44114

DIRECT 216.586.7542 • FAX 216.579.0212 • JREGO@JONESDAY.COMFrom: "Bet h Friedman" <friedman.beth@ecrweb.com>

To: "John Rego" <jrego@JonesDay.com>

Cc: <Chin.Conrad@epamail.epa.gov>, <nelson.brad@ecrweb.com>

Date: 08/21/2012 11:50 AM

Subject: Manganese concentration assumptions

Hi John

—

Conrad asked me to send an email to you with a question for the plant regarding the assumption of a 41

percent manganese (Mn) concentration in the emission estimation procedure in the QSEM report.

We understand that the attempt was to simplify the c alculations and that the most conservative option

was chosen for this effort, i.e., that the Mn concentration determined during the crushing baghouse

stack test would be used for all process fugitives emission estimates.

We note that this modeling scenario is on based on “actual” emissions (we also do a separate scenario

for “allowable” emissions). Based on our preliminary revised analysis of actual emissions, we believe

that use of this factor overstates Mn emissions from the plant. For actual e missions, is it reasonable to

assume that that for the most part, that furnace #1 is primarily used to manufacture SiMn and that

furnace #12 is used to manufacture FeMn? We are considering using Mn emission test data from the

Furnace #1 May 2011 stack te st (SiMn production) and the tapping baghouse May 2011 stack test (SiMn

production), and the 2010 ICR tests for the MOR baghouse and furnace 12 scrubber (FeMn production).

Following are the approximate Mn percentages from the stack test data:

Furnace # 1 baghouse (15%)

Furnace # 1 tapping baghouse (14%)

Furnace #12 scrubber (35%)

MOR baghouse (34%)

Crushing baghouse (41%).

If possible, we would appreciate your comments in the next day or so.

Beth Friedman

Senior Environmental Scientist

EC/R Incorporated

501 Eastowne Drive, Suite 250

Chapel Hill, NC 27514

(919) 433

- 8237