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. Nevertheless, 

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 alloys 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) 

Silicomanganese 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 capable 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 disproportionately 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) + (0.25)(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.COM
From: "Beth 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 calculations 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 emissions, 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 test (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