FREEPORT-MCMORAN COPPER &GOLD Miami Operations 5701 New St. P0 Box 4444 Claypool,
AZ 85532 January 25, 2013 Mr. Thomas Webb U.S. EPA, Region LX Planning Office, Air Division 75 Hawthorne Street (AIR-2) San Francisco, CA 94105 U.S.P.S. Certified Mail 70111570 0000 2503 4277 Dear Mr. Webb: This letter responds

to your letter of January
10, 2013,
in which you requested information related
to the Freeport-McMoRan Miami Inc. (“FMMI”) Smelter regarding potential BART determinations

for SO 2 and NON. As indicated

in our January
18, 2013, letter to Ms. McKaughan (attached for your convenience

in Appendix

S), FMMI has worked diligently

to provide

as much of the requested information

as practicable given the extremely tight timeframe. In our letter, we also requested
the opportunity

to discuss these requests with EPA to assist FMMI
to better understand EPA’s need for the information

so that we can evaluate practical alternatives
for responding that may provide EPA useful information

on a timeframe that reasonably accommodates EPA’s rulemaking schedule.

In the interim, FMMI will continue

its best efforts
to address the remaining information requested. FMMI recognizes
the importance

of providing sufficient information

for EPA to make an informed evaluation

of the sources that are potentially subject

to BART

at the FMMI Smelter. We also understand
the complexity

of a BART determination

for the Smelter and the data necessary

to make such

a determination.

We therefore invite EPA to contact FMMI staff with any questions about the data FMMI

is providing,

so that EPA can develop

a full understanding

of how

a smelter operates. This maybe especially useful
to EPA given the complexities associated with smelter operations and the limited number
of technical specialists who have practical experience with the industry due to the fact that there are only three remaining copper smelters United States, only two of which use
a batch smelting process. A discussion

of FMMI’s responses

to information requested and how that data are being transmitted follows. Data have been provided

in Excel format. When multiple years of data have been requested, FMMI has provided the information

in tabs for each calendar year. Narrative responses will be provided within the body of this letter or as PDF’s contained

in the appendices.
All appendices
are attached

to this letter on a Compact Disk.Mr.ThomasWebb—USEPAJanuary25,2013Page2FMMIalsowishestoinformEPAthatitwillbesubmittingcommentsonEPA’sproposedruledisapprovingArizona’sBARTdeterminationsforNOxandS02.Inpreparingitscomments,FMMIanticipatesconductingitsownanalysesoftheapplicabilityofBARTtothefacility.FMIvIIbelievesthattheinformationgeneratedinthesecommentswillbeusefultoEPAnotonlyinconsideringwhethertofinalizeitsproposeddisapprovalofArizona’sSIP,butalsoinEPA’sassessmentofBARTtopromulgateanyFIPEPAdeterminesisnecessary.FMv’iliseagertoworkwithEPAtohelpRegion9personnelunderstandthecomplexoperationsofthesmelterandFMMI’sunderstandingoftheapplicabilityofBARTandavailableemissionscontrols,andwouldbehappytospeakwithEPA’sstaffandshareFMIVIJ’songoingassessmentofBARTatthesmelter.ResponsetoInformationRequestInformationNeededtoMakeaBARTDeterminationforSO2:1.TheaveragedailymeasurementfortheSO2continuousemissionmonitoringsystem(CEMS)forthesulfuricacidplantsinceJanuary],2005inpermillion(ppm)andthetotaltonsofSO2perdayrecordedbytheSO2CEMSforthesulfuricacidplantsinceJanuary1,2005.PleaseprovidethisinformationinanelectronicformatthatmaybeeditedbyaspreadsheetprogramsuchasExcelorcomparablesoftware.PleasealsoprovideallSO2stacktestdataandrelativeaccuracytestaudits(RATA5)performedforthesulfuricacidplantfortheperiodfromJanuary2005throughDecember2012.InAppendixA,FMMIhasprovidedtherequestedCEMdata.ThisdatapresentedareinExcelformatandwereobtainedfromFMMI’sinternaldatabase.AppendixBcontainselectroniccopiesofallannualcompliancetestingandRATAAuditsperformedbyFMMI’scontractors.ThereportsareinPDFformatandincludedatafromthetests.2.ThedailyproductionofsulfuricacidbythesulfuricacidplantsinceJanuary2005,intons.Describethesourceofthedata.FMMIhasprovidedmonthlysulfuricacidproductioninAppendixC.Acidproductiononadailybasisisnotmaintainedintheordinarycourseofbusiness.3.ThedailyproductionofcopperbythecoppersmeltersinceJanuary2005intons.Describethesourceofthedata..4,’Mr. Thomas Webb— USEPA January 25, 2013 Page

3 In Attachment

D, FMMI has provided daily copper production. This data is based on copper shipped off site for use at other facilities. The source of the data
is FMMI’s production records. 4. The daily quantity
of concentrated

ore processed

by the smelter since January 2005 in tons, along with the average daily percentage

of sulfur of the concentrate. Describe the source of the data. In Appendix

E, FMMI provided the daily quantity
of new copper bearing materials fed to the smelter. FMMI analyzes each concentrated copper ore (or “concentrate”) shipment

it receives for copper, iron, sulfur and then builds

a “bed” of concentrate

for smelter feed. Although the beds contain primarily concentrate, they also include other copper bearing materials. The purpose
of bedding the various materials

is to provide

a consistent feed to the smelter. The source of the data is FMMI’s production records. FMMI has provided the daily sulfur content
of the smelter feed in Appendix

F. The sulfur content provided

is inclusive
of all materials

in the bed. The sulfur content analysis

is generated within FMMI’s analytical laboratory. 5. Monthly material balances
of sulfur (as described

in Specific Provision IV.B.2 and Attachment

D of Title
V Operating Permit 29622) performed since January 2005, along with any support documents for each monthly balance. Appendix

F contains

a compilation

of monthly sulfur balance information

for the years 2005 to 2012 that has been submitted

to ADEQ

in the FMMI monthly reports. 6. Copies of all actual SO 2 emissions calculations performed since January

1, 2005 for any copper smelting equlpment that was submitted

to any regulatory agency. Include with your response

a detailed description

of all equations relied upon, including
the identfl cation of all data inputs into the equation,

a description

of all emissions factors (EFs) relied upon and their source, and all other methods

or data relied upon to perform the calculations; Appendix

G contains excerpts related
to SO 2 emissions from the annual emissions inventories submitted

to ADEQ using their software for the years 2005 to 2011. FMMI has not begun the process
of calculating
the 2012 Emissions Inventory because the ADEQ software for that year has not yet been released. FMMI submits monthly reports
to ADEQ pursuant

to Air Quality Permit 53592. The data elements provided

in the Monthly Report are addressed

in Appendix

A and Appendix

F. 7.

A summary and supporting documentation showing which units at the Facility comprise the BART-eligible source under the Regional Haze Rule (40 CFR part 51, subpart
P) and the BART Guidelines
(40 CFR part 51, appendix

I’). Include any records that indicate which units atMr.ThomasWebb—USEPAJanuary25,2013Page4theFacilitywere“inexistence”onAugust7,1977andwhichunitswere“inoperation”beforeAugust7,1962,asdefinedundertheRegionalHazeRuleandtheBARTGuidelines.AppendixHcontainscorrespondencetoADEQin2007fromFMMI(previouslyPhelpsDodgeMiamiInc.)regardingBARTapplicability.AppendixIcontainsalistofequipmentintheSmelterwithinstallationdate.8.Providethefollowinginformationaboutthesulfuricacidplant.’a.thevolume(liters)ofcatalystineachcatalystbed;SeeAppendixJ.b.Thediameteroftheconverter,’48feet,5inches.c.thetypeofcatalyst(includingtrade-name)ineachcatalystbed;SeeAppendixJ.d.themaximumvolumetriccapacity(liters)ofcatalyst,’Therewasnomaximumcapacityspecifiedbytheoriginalequipmentmanufacturer.Themanufacturerdidspecifyarecommendedcatalystloadingforeachbedwhichisgivenbelow.Notethatthisloadingresultsinverylittleexcessroomremainingineachcatalystbed.Bed185,000litersBed2140,000litersBed3124,000litersBed4155,000literse.theamountandtypeofcatalystreplacedduringeachturnaroundsince2005,’SeeAppendix3.andf[ASARCOisusingcesiumpromotedcatalyst,providethedatethefacilitybeganusingcesiumcatalyst.Mr. Thomas Webb- USEPA January 25, 2013 Page5 FMMI presumes
the reference

to ASARCO

is an error. FMMI has had cesium promoted catalyst

in the Acid Plant Converter since July 2004. 9. Provide
all vendor quotes for cesium promoted catalyst installation that the facility has received. Include any emission estimates provided

by the vendors. Appendix

K includes FMMI’s only available quotation
for catalysts, including cesium promoted catalyst. The catalyst vendors
do not provide any emissions estimates. 10. Provide the following information about process gas capture and treatment: a. Indicate the maximum capacity
of the acid plant
to accept process off gases, including both airflow and inlet SO 2 concentration; FMMI does not have

a ready way to calculate the “maximum” capacity
of the acid plant in terms of airflow and inlet SO 2 concentration.
The nominal design capacity
of the acid plant

is 137,000 standard cubic feet per minute (scfm)

at an SO 2 concentration

of 10.5%. The maximum process offgas flow rate to the acid plant
is determined

by the capacity
of the blowers, which direct 165,000 scfln of offgas
to the acid plant. b. Provide

a detailed description

of what happens

to captured excess gas flow that would otherwise

be vented
to the acid plant when that total gas flow exceeds the capacity
of the acid plant; The captured gas flow cannot exceed the capacity
of the cold gas blowers, which

is 165,000 scfm. During normal operations,
gas flow generally does not exceed 150,000 scfm. If flow approaches 165,000 scffii, an alarm informs the operator who then adjusts facility operations

to ensure flow remains below 165,000 scfm. c. Provide

a detailed analysis
of the capture efficiency
of gases emitted from all copper smelter process equipment; Because
all process gases are ducted
to the acid plant from the Isa furnace, Electric Furnace and Hoboken Converters,
the capture efficiency

of the collection system for SO 2 gasses is intended

to approach nearly 100%. Based on our review of Industry technical data, we have identified SO 2 capture efficiency estimates ranging between

87 and 98% for similar collection systems.

d. Provide

a schematic diagram showing which equipment

at the Facility are captured and controlled

or controllable

by the acid plant; See Appendix

L for the Smelter Offgas Handling Overview flow diagram.Mr. Thomas Webb- USEPA January 25, 2013 Page

6 e. Provide the following information about SO 2 emissions from the Hoboken Converters Secondary System: i. Any and all data, in native format,
on measurements

or calculations

of S02 concentration

in ppm of gas exiting the Secondary System on an hourly basis (or as frequent

as measurements

or calculations are/have been taken/performed)
since January 1, 2005;
ii. The total daily emissions
of S02 in tons from the Secondary System since January

1, 2005, iii. The total daily amount of lime in tons injected into the Secondary System; iv. An estimation,

on a daily basis, of the control efficiency
of the injected lime for SO 2 ; v. For information provided under

8. c.
i and
8. c. ii, a description

of the underlying measurement and/or data used and any calculations performed. It is unclear what
is meant by “Hoboken Converter Secondary System.” Presumably, EPA
is referring

to “secondary capture systems”

as that term
is used under the National Emission Standards
for Hazardous
Air Pollutants (NESHAP)
for Primary Copper Smelters. The side flue intake design of the Hoboken converters

in use at the Smelter does not include

a secondary capture system. f For any emergency bypass vent that is part of the acid plant line, please respond to the following requests: FMMI assumes that what EPA means by the “acid plant line”
is the 90” duct that moves process gases to the acid plant.
If this is incorrect, please clarify. i. Describe the location
of the bypass

in regard

to any particulate matter (PM) controls (i.e. is it before or after each PM control); The bypass stack
is located just downstream

of the acid plant hot gas fans which are located

at the inlet of the acid plant. There are no particulate matter controls between the hot gas fans and the emergency bypass stack. An electrostatic precipitator (ESP)

is located downstream

of the Isa furnace and upstream
of the converter and electric furnace tie in points
to the 90” duct leading to the acid plant. This ESP
is dedicated

to reducing particulate matter reporting

to the acid plant gas cleaning section while the Isa furnace

is in operation. When the bypass stack
is opened during an emergency event, the Isa furnace and the converters
are shut down
as expeditiously

as practicable,

in a controlled manner,Mr. Thomas Webb— USEPA January 25, 2013 Page

7

as part of the standard operating procedure

to minimize PM in accordance with good air quality control practices. ii. Describe what happens

to process off-gases vented through the bypass (i.e. are they emitted directly

to the atmosphere

or controlled); Process off-gases that go to the bypass are directly vented
to atmosphere through a stack. Under normal shut down and startup operations when the bypass stack
is in use, there are no emissions being generated from processing concentrate

as there
is no feed or blast air going
to the Isa vessel, which means there are no active emissions generated. However, there may be some residual emissions from the Isa furnace. Further,
all converters
are positioned

so that process air is not introduced

to the bath for oxidation purposes, which means that there will be no emissions from these units directed

to the acid plant. The residual emissions escape
to the ambient air. Depending

on the temperature

of the bath in the electric furnace, there may be some low level residual sulfur dioxide emissions going
to the stack. Prior to commencing operations (feeding concentrate, blowing converters and raising power on the electric furnace), the acid plant must be up to temperature
and the bypass stack valve must be closed. In the case of a sudden emergency bypass (due to a malfunction),

all feed to the Isa vessel

is stopped, the Isa lance

is pulled from the molten matte/slag bath, the converters
are positioned

so that process air is not introduced

to the bath for oxidation purposes and the power
to the electric furnace

is turned off as soon as the bypass stack valve opens. The only process emissions going
to the stack are those in the duct work between the time the valve

is opened and the process equipment operations
are curtailed. iii. Describe how the gas flow exiting the bypass

is measured; Gas flow and SO 2 concentrations

are measured through the 90 inch duct CEMS. The system includes
an AMETEK 919 CEM and an anubar for measuring flow in the duct. Temperature monitOring

is located just prior to the hot gas fans downstream

of the CEMS.
iv.
In a chart format, since January

1, 2005, spec5’ the total amount of gas vented through the bypass on a daily basis. Describe the source of the data.Mr. Thomas Webb- USEPA January 25, 2013 Page

8 FMMI has provided daily SO 2 (in tons per day) vented through the bypass stack in Appendix
M. Flow data for each emission event

is not available

at this time because significant efforts for data reduction would be required. EPA should note that emissions from the bypass stack are not daily events and can last from less than an hour to a full day. Concentrations

of SO 2 and flow rates will vary upon the reason for using the bypass stack. Should EPA require additional information, FMIVII and EPA will need to discuss EPA’s data needs
to ensure

a full package that meets the intended use of the data. g. Provide

a detailed description

of S0 2 -laden gas flow emittedfrom

all copper smelter process equipment

at the Facility (e.g. maximum and lypicalfiow rates in actual cubic feet per minute (acfin), temperature,
and SO 2 concentration

in ppm), and whether

it is currently vented
to the acid plant,
to other controls

in place, or to the atmosphere uncontrolled. SO 2 laden gas is emitted from the following smelter process equipment

to the acid plant: • Isa smelting vessel • Electric furnace • Hoboken converters FMMI cannot calculate the maximum

or typical flow rate in such areas reliably. While there
is some process instrumentation

that could provide

a rough estimate
of these flows, they are not accurately measured until the 90” duct. FMN’fl

is providing

a diagram (Smelter Offgas Handling Overview)

in Appendix

L. Information Needed

to Make

a BART Determination

for NO,j 1.

A description

of existing NO sources and controls
all copper smelter process equipment at the Facility. FMMI

is not certain what EPA means by “all copper smelter process equipment.” For purposes
of this response, FMMI interprets

it to mean the Hoboken Converters and the Isa Furnace. The principal NO sources from this equipment include the Isa Lance and the Isa Auxiliary Boiler, which both use natural gas. 2. The average NOx emissions from any copper smelter process equipment

at the Facility since January, 2005 calculated

in tons per calendar month and the assumptions
and emission factors relied upon to perform the calculations. Please provide all NO stack tests performed

on any of this equipment. There are no continuous emissions monitoring system(s)
for NO emissions from this equipment. FMMI performs testing of each stack semi-annually.
This data is presented

in Appendix

N, and was derived from NOx performance stack testing (found in Appendix
B).Mr. Thomas Webb— USEPA January 25, 2013 Page

9 3.

A description

of equipment and practices used to directly
or indirectly measure NOX emissions from this equipment. FMMI retains
an outside contractor (AECOM)

to perform stack testing,

as required

in Air Quality Permit 53592, dated November
26, 2012. Appendix

0 contains the NOx testing method used by AECOM. 4.

A detailed description

of all fuel burners associated with any copper smelter process equipment

at the Facility including
the manufacturer, model number, type offuel combusted, maximum fuel combustion rate, and guaranteed NO emission rate. As noted above, FMMI

is not certain what EPA means by “all copper smelter process equipment.”
For purposes
of this response, FMMI interprets

it to mean the Hoboken Converters and the Isa Furnace. The principal N0 sources from this equipment include the Isa Lance and the Isa Auxiliary Boiler, which both use natural gas. There are no ratings for the Isa lance. The manufacturer’s information

for the Isa Auxiliary Boiler

is found
in Appendix

G. Air Quality Permit 53592 (page 54) has
a NO limit for the Isa Auxiliary Boiler listed
at 1.8 lb./hr. and 97.5 Ib./hr. for Process Gasses from exiting the Tailstack (Air Quality Permit 53592, page 25). This limit was included in the 1998 NO PSD permit issued by ADEQ. 5. Records and summaries

of each type offuel, including sulfur content and higher heating value, combusted

in each piece of copper smelter process equipment

at the Facility,
on a monthly basis. Based on FMMI’s understanding

of “copper smelter production equipment,”

the only available information

is the natural gas used in the Isa furnace (used as supplementary fuel.) Appendix

Q contains the natural gas usage
in the Isa. Appendix

R contains

El Paso Natural Gas’ Federal Energy Regulatory Commission filing for 2011.
In this filing, natural gas is listed as not to exceed

5 grains total sulfur /100 cubic feet of natural gas. The higher heating values are only available for the calendar years 2010, 2011 and 2012
at this time. Previous years will need to be obtained
by El Paso Natural Gas.*********************************************** FMMI appreciates
the opportunity

to provide the information

to facilitate EPA’s evaluation

of BART issues related
to the Smelter. Should EPA require clarification

on any of the data presented

in this response, please feel free to call Mr. Chris West, Chief EnvironmentalMr.ThomasWebb-USEPAJanuary25,2013Page10Engineer—AirQualityatFMMI.Hisdirectlineis928-473-7149andhisemailischristopherwest@fini.com.Verytrulyyours,DerekCookeGeneralManagerAttachment(CDwithAppendices)CC:EricMassey,ADEQFMIDistribution