DAQ-2024-011080

DAQE-AN105710049-24

{{$d1 }}

Jenny Esker
Rio Tinto Kennecott Utah Copper LLC
4700 Daybreak Parkway
South Jordan, UT 84095
[e-mail]

Dear Ms. Esker:

Re: Approval Order: Modification to Approval Order to DAQE-AN105710044-18, to Add
Generators
Project Number: N105710049

The attached Approval Order (AO) is issued pursuant to the Notice of Intent (NOI) received on February
9, 2024. Rio Tinto Kennecott Utah Copper LLC must comply with the requirements of this AO, all
applicable state requirements (R307), and Federal Standards.

The project engineer for this action is Tad Anderson, who can be contacted at [phone] or
[e-mail]. Future correspondence on this AO should include the engineer's name as well as
the DAQE number shown on the upper right-hand corner of this letter. No public comments were
received on this action.

Sincerely,

{{$s }}

Bryce C. Bird
Director

BCB:TA:jg

cc: Salt Lake County Health Department
EPA Region 8

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

September 23, 2024

STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

{{#s=Sig_es_:signer1:signature}}
{{#d1=date1_es_:signer1:date:format(date, "mmmm d, yyyy")}}
{{#d2=date1_es_:signer1:date:format(date, "mmmm d, yyyy"):align(center)}}

APPROVAL ORDER
DAQE-AN105710049-24
Modification to Approval Order to DAQE-AN105710044-18,
to Add Generators

Prepared By
Tad Anderson, Engineer
[phone]
[e-mail]

Issued to
Rio Tinto Kennecott Utah Copper LLC - Mine & Copperton Concentrator

Issued On
{{$d2 }}

Issued By

{{$s }}

Bryce C. Bird
Director
Division of Air Quality

September 23, 2024
TABLE OF CONTENTS

TITLE/SIGNATURE PAGE ....................................................................................................... 1
GENERAL INFORMATION ...................................................................................................... 3
CONTACT/LOCATION INFORMATION ............................................................................... 3
SOURCE INFORMATION ........................................................................................................ 3
General Description ................................................................................................................ 3
NSR Classification .................................................................................................................. 3
Source Classification .............................................................................................................. 3
Applicable Federal Standards ................................................................................................. 3
Project Description.................................................................................................................. 4
SUMMARY OF EMISSIONS .................................................................................................... 4
SECTION I: GENERAL PROVISIONS .................................................................................... 5
SECTION II: PERMITTED EQUIPMENT .............................................................................. 5
SECTION II: SPECIAL PROVISIONS ..................................................................................... 7
PERMIT HISTORY ..................................................................................................................... 9
ACRONYMS ............................................................................................................................... 10

DAQE-AN105710049-24
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
Rio Tinto Kennecott Utah Copper LLC Kennecott Utah Copper LLC – Mine & Copperton Concentrator

Mailing Address Physical Address
4700 Daybreak Parkway 8362 West 10200 South
South Jordan, UT 84095 Bingham Canyon, UT 84006

Source Contact UTM Coordinates
Name: Jenny Esker 407,000 m Easting
Phone: [phone],493,000 m Northing
Email: [e-mail] Datum NAD27
UTM Zone 12
SIC code 1021 (Copper Ores)

SOURCE INFORMATION
General Description
Rio Tinto Kennecott Utah Copper LLC (Kennecott) operates the Copperton Concentrator that receives the
ore from the Bingham Canyon Mine, which is run through the grinding lines and made into a slurry. The
slurry from the ore is fed into the flotation circuits, which are mixed with reagents and aerated to float the
copper from the ore and routed to the refinery to be further processed.

NSR Classification
Minor Modification at Minor Source

Source Classification
Located in Salt Lake City UT PM2.5 NAA, Salt Lake County SO2 NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
NSPS (Part 60), A: General Provisions
NSPS (Part 60), LL: Standards of Performance for Metallic Mineral Processing Plants
NSPS (Part 60), IIII: Standards of Performance for Stationary Compression Ignition Internal
Combustion Engines
NSPS (Part 60), JJJJ: Standards of Performance for Stationary Spark Ignition Internal
Combustion Engines
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
DAQE-AN105710049-24
Page 4

Stationary Reciprocating Internal Combustion Engines
Title V (Part 70) Area Source

Project Description
Kennecott is proposing to use some of the tailings generated at the Concentrator as feed material for the
Paste Plant at the Bingham Canyon Mine. Kennecott requires the use of an emergency generator (250-kW
standby emergency generator, (EPA) Tier 4 certified engine) to have backup power at the Concentrator in
the event of a power failure. During a power failure, the materials being directed at the Paste Plant could
slide back through the pipe to the Concentrator where the force of the material would present a dangerous
scenario to equipment and people in the area. The emergency generator would ensure that pumping
capacity remains in place in the event of a power outage to mitigate the potential hazards.

Kennecott is also proposing to add a mobile diesel-powered air compressor unit (540-HP diesel engine,
(EPA) Tier 4 certified engine) to meet compressed air needs at the Concentrator.

Both engines require hour limitations that have been included in the permit modification.

Process Description
Ore from the Bingham Canyon Mine is stockpiled in the A-frame enclosure. The ore is fed from the
enclosure to the grinding lines through the semi-autogenous grinding (SAG) mills and ball mill, making
the ore into slurry. The slurry is sent through cyclone clusters, the cyclone overflow is fed into the
flotation circuits, and the cyclone underflow is sent to the ball mills for further size reduction before being
sent back to the cyclones and on to the flotation circuit.

In the flotation circuits, overflow is mixed with reagents and aerated to float copper and other valuable
by-products from the ore. Concentrate is pumped to the existing regrinding circuit, while tailings gravity
flows to a collection trench. Tailings from the collection trenches are fed to the tailings thickener feed
distributor and then transported by gravity flow to the tailings impoundment for final deposition.
Thickener overflow is pumped back to the process water reservoir.

SUMMARY OF EMISSIONS

The emissions listed below are an estimate of the total potential emissions from the source. Some
rounding of emissions is possible.

Criteria Pollutant Change (TPY) Total (TPY)
Ammonia 0.00 0.27
CO2 Equivalent 729.0 10914.00
Carbon Monoxide 4.34 14.21
Nitrogen Oxides 0.59 11.26
Particulate Matter - PM10 0.03 25.33
Particulate Matter - PM2.5 0.03 13.89
Sulfur Dioxide 1.11 1.21
Volatile Organic Compounds 0.23 4.27

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
DAQE-AN105710049-24
Page 5

Cyanide Compounds (CAS #143339) 0 100
Generic HAPs (CAS #GHAPS) 102 122
Change (TPY) Total (TPY)
Total HAPs 0.05 0.11

SECTION I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101] I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]
I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions covered by this AO must be reviewed and approved. [R307-401-1] I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of two (2) years. [R307-401-8]
I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and operate any equipment approved under this AO, including associated air pollution control equipment, in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available to the Director which may include, but is not limited to, monitoring results, opacity observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4] I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns. [R307-107]
I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150] I.8 The owner/operator shall submit documentation of the status of construction or modification to the Director within 18 months from the date of this AO. This AO may become invalid if construction is not commenced within 18 months from the date of this AO or if construction is discontinued for 18 months or more. To ensure proper credit when notifying the Director, send the documentation to the Director, attn.: NSR Section. [R307-401-18]

SECTION II: PERMITTED EQUIPMENT
II.A THE APPROVED EQUIPMENT II.A.1 Plant Wide
Copperton Concentrator

DAQE-AN105710049-24
Page 6

II.A.2 One (1) Feed Dryer Oil Heater Feed dryer oil heater for product molybdenite dryer Rated capacity: 5.7 MMBtu/hr Fuel type: Natural gas Product molybdenite dryer with venturi scrubber II.A.3 One (1) Product Dryer Oil Heater Product dryer oil heater* for product molybdenite dryer
Rated capacity: 2.2 MMBtu/hr Fuel type: Natural gas Product: molybdenite dryer with venturi scrubber
*This equipment is listed for informational purposes only.
II.A.4 Molybdenite Loading Six (6) molybdenite storage bins II.A.5 Molybdenite Storage
Two (2) molybdenite storage bins

II.A.6 Two (2) Cooling Towers Closed-circuit fluid cooling tower for motors used in the grinding circuit
II.A.7 Bag Loading Molybdenite bag loading operations

II.A.8 Cleaning System Vacuum cleaning system with baghouse
II.A.9 Ore Sorting Plant
Ore sorting baghouse and sample preparation baghouse
II.A.10 Metallurgical Laboratory Two (2) baghouses II.A.11 Three (3) Pebble Crushers
Pebble crushers with associated enclosed conveyors and enclosed drop points

II.A.12 Degreasing Parts Washers
II.A.13 Four (4) Lime Silos
Controlled: bin vents
II.A.14 Three (3) Storage Tanks Capacity: 25,000 gallons (each) Contents: frother, collector, and fuel oil
II.A.15 One (1) Emergency Generator
Fueled: Diesel (NEW)
Maximum rating: 4,357 horsepower

II.A.16 One (1) Emergency Generator Fueled: Liquid propane-fired Maximum rating: 75 brake horsepower
DAQE-AN105710049-24
Page 7

II.A.17 One (1) Air Compressor Engine Fueled: Diesel (NEW) Maximum rating: 540 horsepower II.A.18 Miscellaneous Combustion Sources
Natural gas-fired equipment, including water heaters or comfort heaters that are each individually rated at less than 5 MMBTU/hr. This equipment is listed for informational purposes only.

II.A.19 MH Pilot Plant Feed Hopper Conveyors Baghouse on HM pilot ore treatment plant building with a control efficiency of 99% II.A.20 Cyanide Circuit
Two (2) sodium cyanide storage tanks Capacity: 8,500 gallons (each)

II.A.21 Two (2) Lime Slaker Scrubbers Type: Single stage

SECTION II: SPECIAL PROVISIONS II.B REQUIREMENTS AND LIMITATIONS
II.B.1 Plant Wide Requirements
II.B.1.a Visible emissions from the following emission points shall not exceed the following values: A. Pebble crushers (subject to NSPS, Subpart LL) - 7% opacity for building exterior. B. Cone crusher (subject to NSPS, Subpart LL) - 10% opacity. C. Fugitive emission points (subject to NSPS, Subpart LL) - 10% opacity. D. Liquid propane (LP) emergency generator - 10% opacity. E. All other points - 10% opacity. F. Baghouse on molybdenite storage bins (subject to NSPS, Subpart LL) - 7% opacity. G. Diesel-fired emergency equipment - 20% opacity. Opacity observations of emissions from stationary sources shall be conducted in accordance with 40 CFR 60, Appendix A, Method 9. For sources that are subject to NSPS, opacity shall be determined by conducting observations in accordance with 40 CFR 60.11(b) and 40 CFR 60, Appendix A, Method 9. [40 CFR 60 Subpart LL, R307-305-3]
DAQE-AN105710049-24
Page 8

II.B.1.b All baghouses shall be operated as follows: A. Whenever the vacuum cleaning system is in use, all exhaust gases from the vacuum cleaning system shall pass through the baghouse. B. All exhaust gases from the metallurgical laboratory sample preparation hoods shall pass through an operating baghouse. [R307-401-8] II.B.1.c The pH of the circuit using cyanide shall be maintained at a value no less than 9. [R307-401-8]

II.B.1.c.1 The pH shall be continuously monitored (+/- 0.5) in the flotation circuit upstream of the cyanide circuit. Records shall be maintained as per Condition I.4. [R307-401-8]
II.B.1.d All wet scrubbers shall comply with 40 CFR 60.384 and 60.385. [40 CFR 60 Subpart A]
II.B.1.e Kennecott shall use only natural gas as a primary fuel and liquid propane as a backup fuel in the dryer oil heaters and liquid propane as a fuel for the 75 hp emergency generator. [R307-401-8] II.B.2 Roads and Fugitives
II.B.2.a To control fugitive emissions, the following controls shall be applied: A. A baghouse shall control the PM10 and PM2.5 from the MH Pilot Ore Treatment Plant. B. All copperton milling conveyors shall be partially enclosed. C. All copperton milling conveyor transfer points shall be enclosed. D. The pebble crushers shall be enclosed in a building. [R307-309, R307-401-8] II.B.2.b Water sprays or chemical dust suppression sprays shall be installed at the following points to
control fugitive emissions:
A. All pebble crusher feed conveyors.

The sprays shall operate whenever dry conditions warrant or as determined necessary by the Director. [R307-309]

II.B.3 Generator Engine Requirements
II.B.3.a Kennecott shall not exceed 2000 hours of operation of the diesel-fired air compressor per rolling 12-month total. [R307-401-8]

II.B.3.a.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of diesel-fired air compressor engine shall be kept in a log. [R307-401-8]
II.B.3.a.2 To determine the duration of operation, the owner/operator shall install a non-resettable hour
meter for the diesel-fired air compressor engine. [R307-401-8]

II.B.3.b The owner/operator shall not operate each emergency engine on site for more than 100 hours per rolling 12-month period during non-emergency situations. There is no time limit on the use of the engines during emergencies. [R307-401-8]
DAQE-AN105710049-24
Page 9

II.B.3.b.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of each emergency engine shall be kept in a log and shall include the following: a. The date the emergency engine was used. b. The duration of operation in hours. c. The reason for the emergency engine usage. [R307-401-8] II.B.3.b.2 To determine the duration of operation, the owner/operator shall install a non-resettable hour
meter for each emergency engine. [R307-401-8]
II.B.3.c The owner/operator shall only use diesel fuel (e.g., fuel oil #1, #2, or diesel fuel oil additives) as fuel in each emergency engine. [R307-401-8] II.B.3.d The owner/operator shall only combust diesel fuel that meets the definition of ultra-low sulfur
diesel (ULSD), which has a sulfur content of 15 ppm or less. [R307-401-8]

II.B.3.d.1 To demonstrate compliance with the ULSD fuel requirement, the owner/operator shall maintain records of diesel fuel purchase invoices or obtain certification of sulfur content from the diesel fuel supplier. The diesel fuel purchase invoices shall indicate that the diesel fuel meets the ULSD requirements. [R307-401-8]
II.B.3.e The owner/operator shall limit the use of the ventilation system generators 6-9 to the following:
a. Testing of the emergency generators shall be between 8 a.m. and 8 p.m.

b. Only one (1) emergency generator shall be tested at the same time.
[R307-410]

II.B.4 SIP Requirement II.B.4.a The emissions from the Product Molybdenite Dryers shall be controlled with a scrubber during
operation of the dryers. [SIP Section IX.H.12]

II.B.4.a.1 During operation of the dryers, the static pressure differential between the inlet and outlet of the scrubber shall be within the manufacturer's recommended range and shall be recorded weekly. [R307-401] II.B.4.a.2 The manometer or the differential pressure gauge shall be calibrated according to the
manufacturer's instructions at least once per year. [R307-401]

PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents:
Supersedes AO DAQE-AN105710044-18 dated August 21, 2018 Is Derived From NOI dated February 9, 2024 Incorporates Additional Information dated February 27, 2024
DAQE-AN105710049-24
Page 10

ACRONYMS
The following lists commonly used acronyms and associated translations as they apply to this document: 40 CFR Title 40 of the Code of Federal Regulations AO Approval Order BACT Best Available Control Technology CAA Clean Air Act CAAA Clean Air Act Amendments CDS Classification Data System (used by Environmental Protection Agency to classify sources by size/type) CEM Continuous emissions monitor CEMS Continuous emissions monitoring system CFR Code of Federal Regulations CMS Continuous monitoring system CO Carbon monoxide CO2 Carbon Dioxide CO2e Carbon Dioxide Equivalent - Title 40 of the Code of Federal Regulations Part 98, Subpart A, Table A-1 COM Continuous opacity monitor DAQ/UDAQ Division of Air Quality DAQE This is a document tracking code for internal Division of Air Quality use EPA Environmental Protection Agency FDCP Fugitive dust control plan GHG Greenhouse Gas(es) - Title 40 of the Code of Federal Regulations 52.21 (b)(49)(i) GWP Global Warming Potential - Title 40 of the Code of Federal Regulations Part 86.1818-12(a) HAP or HAPs Hazardous air pollutant(s) ITA Intent to Approve
LB/YR Pounds per year
MACT Maximum Achievable Control Technology MMBTU Million British Thermal Units NAA Nonattainment Area NAAQS National Ambient Air Quality Standards NESHAP National Emission Standards for Hazardous Air Pollutants NOI Notice of Intent
NOx Oxides of nitrogen
NSPS New Source Performance Standard
NSR New Source Review
PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size
PSD Prevention of Significant Deterioration
PTE Potential to Emit
R307 Rules Series 307
R307-401 Rules Series 307 - Section 401
SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act
Title V Title V of the Clean Air Act
TPY Tons per year
UAC Utah Administrative Code
VOC Volatile organic compounds

DAQE-IN105710049-24

August 15, 2024

Jenny Esker
Kennecott Utah Copper LLC
4700 Daybreak Parkway
South Jordan, UT 84095
[e-mail]

Dear Ms. Esker:

Re: Intent to Approve: Modification to Approval Order to DAQE-AN105710044-18, to Add
Generators
Project Number: N105710049

The attached document is the Intent to Approve (ITA) for the above-referenced project. The ITA is
subject to public review. Any comments received shall be considered before an Approval Order (AO) is
issued. The Division of Air Quality is authorized to charge a fee for reimbursement of the actual costs
incurred in the issuance of an AO. An invoice will follow upon issuance of the final AO.

Future correspondence on this ITA should include the engineer's name, Tad Anderson, as well as the
DAQE number as shown on the upper right-hand corner of this letter. Tad Anderson, can be reached at
[phone] or [e-mail], if you have any questions.

Sincerely,

{{$s }}

Jon L. Black, Manager
New Source Review Section

JLB:TA:jg

cc: Salt Lake County Health Department
EPA Region 8

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

* ) ' & — 0 " @ D v A ? A C ? G w C B ˜
STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

INTENT TO APPROVE
DAQE-IN105710049-24
Modification to Approval Order to DAQE-AN105710044-18
to Add Generators

Prepared By
Tad Anderson, Engineer
[phone]
[e-mail]

Issued to
Kennecott Utah Copper LLC - Mine & Copperton Concentrator

Issued On
August 15, 2024

{{$s }}

New Source Review Section Manager
Jon L. Black
{{#s=Sig_es_:signer1:signature}}
* ) ' & — 0 " @ D v A ? A C ? G w C B ˜

TABLE OF CONTENTS

TITLE/SIGNATURE PAGE ....................................................................................................... 1
GENERAL INFORMATION ...................................................................................................... 3
CONTACT/LOCATION INFORMATION ............................................................................... 3
SOURCE INFORMATION ........................................................................................................ 3
General Description ................................................................................................................ 3
NSR Classification .................................................................................................................. 3
Source Classification .............................................................................................................. 3
Applicable Federal Standards ................................................................................................. 3
Project Description.................................................................................................................. 4
SUMMARY OF EMISSIONS .................................................................................................... 4
PUBLIC NOTICE STATEMENT............................................................................................... 5
SECTION I: GENERAL PROVISIONS .................................................................................... 5
SECTION II: PERMITTED EQUIPMENT .............................................................................. 6
SECTION II: SPECIAL PROVISIONS ..................................................................................... 7
PERMIT HISTORY ................................................................................................................... 10
ACRONYMS ............................................................................................................................... 11

DAQE-IN105710049-24
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
Kennecott Utah Copper LLC Kennecott Utah Copper LLC - Mine & Copperton Concentrator

Mailing Address Physical Address
4700 Daybreak Parkway 8362 West 10200 South
South Jordan, UT 84095 Bingham Canyon, UT 84006

Source Contact UTM Coordinates
Name: Jenny Esker 407,000 m Easting
Phone: [phone],493,000 m Northing
Email: [e-mail] Datum NAD27
UTM Zone 12
SIC code 1021 (Copper Ores)

SOURCE INFORMATION
General Description
Rio Tinto Kennecott Utah Copper LLC (Kennecott) operates the Copperton Concentrator that receives the
ore from the Bingham Canyon Mine, which is run through the grinding lines and made into a slurry. The
slurry from the ore is fed into the flotation circuits, where it is mixed with reagents, aerated to float the
copper from the ore, and routed to the refinery to be further processed.
NSR Classification
Minor Modification at Minor Source

Source Classification
Located in Salt Lake City UT PM2.5 NAA, Salt Lake County SO2 NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
NSPS (Part 60), A: General Provisions
NSPS (Part 60), LL: Standards of Performance for Metallic Mineral Processing Plants
NSPS (Part 60), IIII: Standards of Performance for Stationary Compression Ignition Internal
Combustion Engines
NSPS (Part 60), JJJJ: Standards of Performance for Stationary Spark Ignition Internal
Combustion Engines
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines
Title V (Part 70) Area Source
DAQE-IN105710049-24
Page 4

Project Description
Kennecott is proposing to use some of the tailings generated at the Concentrator as feed material for the
Paste Plant at the Bingham Canyon Mine. Kennecott requires the use of an emergency generator (250-kW
standby emergency generator, (EPA) Tier 4 certified engine) to have backup power at the Concentrator in
the event of a power failure. During a power failure, the materials being directed at the Paste Plant could
slide back through the pipe to the Concentrator, where the force of the material would present a dangerous
scenario to equipment and people in the area. The emergency generator would ensure that pumping
capacity remains in place in the event of a power outage to mitigate the potential hazards.

Kennecott is also proposing to add a mobile diesel-powered air compressor unit (540-HP diesel engine,
EPA Tier 4 certified engine) to meet compressed air needs at the Concentrator.

Both engines require hourly limitations that have been included in the permit modification.

Process Description
Ore from the Bingham Canyon Mine is stockpiled in the A-frame enclosure. The ore is fed from the
enclosure to the grinding lines through the semi-autogenous grinding (SAG) mills and ball mill, making
the ore into slurry. The slurry is sent through cyclone clusters, the cyclone overflow is fed into the
flotation circuits, and the cyclone underflow is sent to the ball mills for further size reduction before being
sent back to the cyclones and on to the flotation circuit.

In the flotation circuits, overflow is mixed with reagents and aerated to float copper and other valuable
by-products from the ore. Concentrate is pumped to the existing regrinding circuit, while tailings gravity
flow to a collection trench. Tailings from the collection trenches are fed to the tailings thickener feed
distributor and then transported by gravity flow to the tailings impoundment for final deposition.
Thickener overflow is pumped back to the process water reservoir.

SUMMARY OF EMISSIONS

The emissions listed below are an estimate of the total potential emissions from the source. Some
rounding of emissions is possible.

Criteria Pollutant Change (TPY) Total (TPY)
Ammonia 0.00 0.27
CO2 Equivalent 729.0 10914.00
Carbon Monoxide 4.34 14.21
Nitrogen Oxides 0.59 11.26
Particulate Matter - PM10 0.03 25.33
Particulate Matter - PM2.5 0.03 13.89
Sulfur Dioxide 1.11 1.21
Volatile Organic Compounds 0.23 4.27

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Cyanide Compounds (CAS #143339) 0 100
Generic HAPs (CAS #GHAPS) 102 122
Change (TPY) Total (TPY)
Total HAPs 0.05 0.11
DAQE-IN105710049-24
Page 5

PUBLIC NOTICE STATEMENT
The NOI for the above-referenced project has been evaluated and has been found to be consistent with the requirements of UAC R307. Air pollution producing sources and/or their air control facilities may not be constructed, installed, established, or modified prior to the issuance of an AO by the Director. A 30-day public comment period will be held in accordance with UAC R307-401-7. A notification of the intent to approve will be published in the Salt Lake Tribune and Deseret News on August 18, 2024. During the public comment period, the proposal and the evaluation of its impact on air quality will be available for the public to review and provide comments. If anyone so requests a public hearing within 15 days of publication, it will be held in accordance with UAC R307-401-7. The hearing will be held as close as practicable to the location of the source. Any comments received during the public comment period and the hearing will be evaluated. The proposed conditions of the AO may be changed as a result of the comments received.

SECTION I: GENERAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO.

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101] I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]
I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions covered by this AO must be reviewed and approved. [R307-401-1] I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of two (2) years. [R307-401-8]
I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and operate any equipment approved under this AO, including associated air pollution control equipment, in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available to the Director which may include, but is not limited to, monitoring results, opacity observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4] I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns. [R307-107]
I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]
DAQE-IN105710049-24
Page 6

I.8 The owner/operator shall submit documentation of the status of construction or modification to the Director within 18 months from the date of this AO. This AO may become invalid if construction is not commenced within 18 months from the date of this AO or if construction is discontinued for 18 months or more. To ensure proper credit when notifying the Director, send the documentation to the Director, attn.: NSR Section. [R307-401-18]

SECTION II: PERMITTED EQUIPMENT

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO.
II.A THE APPROVED EQUIPMENT II.A.1 Plant Wide Copperton Concentrator
II.A.2 One (1) Feed Dryer Oil Heater Feed dryer oil heater for product molybdenite dryer Rated capacity: 5.7 MMBtu/hr Fuel type: Natural gas Product molybdenite dryer with venturi scrubber II.A.3 One (1) Product Dryer Oil Heater Product dryer oil heater* for product molybdenite dryer Rated capacity: 2.2 MMBtu/hr Fuel type: Natural gas Product: molybdenite dryer with venturi scrubber *This equipment is listed for informational purposes only.
II.A.4 Molybdenite Loading Six (6) molybdenite storage bins II.A.5 Molybdenite Storage Two (2) molybdenite storage bins
II.A.6 Two (2) Cooling Towers Closed-circuit fluid cooling tower for motors used in the grinding circuit. II.A.7 Bag Loading Molybdenite bag loading operations
II.A.8 Cleaning System Vacuum cleaning system with a baghouse II.A.9 Ore Sorting Plant
Ore sorting baghouse and sample preparation baghouse
II.A.10 Metallurgical Laboratory Two (2) baghouses II.A.11 Three (3) Pebble Crushers Pebble crushers with associated enclosed conveyors and enclosed drop points.

DAQE-IN105710049-24
Page 7

II.A.12 Degreasing Parts Washers
II.A.13 Four (4) Lime Silos Controlled: bin vents
II.A.14 Three (3) Storage Tanks Capacity: 25,000 gallons (each) Contents: frother, collector, and fuel oil
II.A.15 One (1) Emergency Generator Fueled: Diesel (NEW) Maximum rating: 4,357 horsepower

II.A.16 One (1) Emergency Generator Fueled: Liquid propane-fired Maximum rating: 75 brake horsepower II.A.17 One (1) Air Compressor Engine
Fueled: Diesel (NEW)
Maximum rating: 540 horsepower
II.A.18 Miscellaneous Combustion Sources Natural gas-fired equipment including water heaters or comfort heaters that are each individually rated at less than 5 MMBTU/hr. This equipment is listed for informational purposes only.
II.A.19 MH Pilot Plant
Feed Hopper Conveyors
Baghouse on HM pilot ore treatment plant building with a control efficiency of 99%.

II.A.20 Cyanide Circuit Two (2) sodium cyanide storage tanks Capacity: 8,500 gallons (each)
II.A.21 Two (2) Lime Slaker Scrubbers
Type: Single stage

SECTION II: SPECIAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO. II.B REQUIREMENTS AND LIMITATIONS II.B.1 Plant Wide Requirements
DAQE-IN105710049-24
Page 8

II.B.1.a Visible emissions from the following emission points shall not exceed the following values: A. Pebble crushers (subject to NSPS, Subpart LL) - 7% opacity for building exterior. B. Cone crusher (subject to NSPS, Subpart LL) - 10% opacity. C. Fugitive emission points (subject to NSPS, Subpart LL) - 10% opacity. D. Liquid propane (LP) emergency generator - 10% opacity. E. All other points - 10% opacity. F. Baghouse on molybdenite storage bins (subject to NSPS, Subpart LL) - 7% opacity. G. Diesel-fired emergency equipment - 20% opacity. Opacity observations of emissions from stationary sources shall be conducted in accordance with 40 CFR 60, Appendix A, Method 9. For sources that are subject to NSPS, opacity shall be determined by conducting observations in accordance with 40 CFR 60.11(b) and 40 CFR 60, Appendix A, Method 9. [40 CFR 60 Subpart LL, R307-305-3]
II.B.1.b All baghouses shall be operated as follows:
A. Whenever the vacuum cleaning system is in use, all exhaust gases from the vacuum
cleaning system shall pass through the baghouse.
B. All exhaust gases from the metallurgical laboratory sample preparation hoods shall
pass through an operating baghouse.
[R307-401-8]

II.B.1.c The pH of the circuit using cyanide shall be maintained at a value no less than 9. [R307-401-8] II.B.1.c.1 The pH shall be continuously monitored (+/- 0.5) in the flotation circuit upstream of the cyanide
circuit. Records shall be maintained as per Condition I.4. [R307-401-8]

II.B.1.d All wet scrubbers shall comply with 40 CFR 60.384 and 60.385. [40 CFR 60 Subpart A]
II.B.1.e KUC shall use only natural gas as a primary fuel and liquid propane as a backup fuel in the dryer
oil heaters and liquid propane as a fuel for the 75 hp emergency generator. [R307-401-8]
II.B.2 Roads and Fugitives
II.B.2.a To control fugitive emissions, the following controls shall be applied:

A. A baghouse shall control the PM10 and PM2.5 from the MH Pilot Ore Treatment Plant.

B. All copperton milling conveyors shall be partially enclosed.

C. All copperton milling conveyor transfer points shall be enclosed.

D. The pebble crushers shall be enclosed in a building.

[R307-309, R307-401-8]

DAQE-IN105710049-24
Page 9

II.B.2.b Water sprays or chemical dust suppression sprays shall be installed at the following points to control fugitive emissions: A. All pebble crusher feed conveyors. The sprays shall operate whenever dry conditions warrant or as determined necessary by the Director. [R307-309]
II.B.3 Generator Engine Requirements
II.B.3.a KUC shall not exceed 2000 hours of operation of the diesel-fired air compressor per rolling 12-month total. [R307-401-8]
II.B.3.a.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of diesel-fired air compressor engine shall be kept in a log.
[R307-401-8]
II.B.3.a.2 To determine the duration of operation, the owner/operator shall install a non-resettable hour meter for the diesel-fired air compressor engine. [R307-401-8] II.B.3.b The owner/operator shall not operate each emergency engine on site for more than 100 hours per
rolling 12-month period during non-emergency situations. There is no time limit on the use of
the engines during emergencies. [R307-401-8]
II.B.3.b.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of each emergency engine shall be kept in a log and shall include the following: a. The date the emergency engine was used. b. The duration of operation in hours. c. The reason for the emergency engine usage. [R307-401-8]
II.B.3.b.2 To determine the duration of operation, the owner/operator shall install a non-resettable hour
meter for each emergency engine. [R307-401-8]
II.B.3.c The owner/operator shall only use diesel fuel (e.g., fuel oil #1, #2, or diesel fuel oil additives) as fuel in each emergency engine. [R307-401-8] II.B.3.d The owner/operator shall only combust diesel fuel that meets the definition of ultra-low sulfur
diesel (ULSD), which has a sulfur content of 15 ppm or less. [R307-401-8]

II.B.3.d.1 To demonstrate compliance with the ULSD fuel requirement, the owner/operator shall maintain records of diesel fuel purchase invoices or obtain certification of sulfur content from the diesel fuel supplier. The diesel fuel purchase invoices shall indicate that the diesel fuel meets the ULSD requirements. [R307-401-8]
DAQE-IN105710049-24
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II.B.3.e The owner/operator shall limit the use of the ventilation system generators 6-9 to the following: a. Testing of the emergency generators shall be between 8 a.m. and 8 p.m. b. Only one (1) emergency generator shall be tested at the same time. [R307-410]
II.B.4 SIP Requirement
II.B.4.a The emissions from the Product Molybdenite Dryers shall be controlled with a scrubber during operation of the dryers. [SIP Section IX.H.12]
II.B.4.a.1 During operation of the dryers, the static pressure differential between the inlet and outlet of the scrubber shall be within the manufacturer's recommended range and shall be recorded weekly. [R307-401]

II.B.4.a.2 The manometer or the differential pressure gauge shall be calibrated according to the manufacturer's instructions at least once per year. [R307-401]

PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents: Supersedes AO DAQE-AN105710044-18 dated August 21, 2018 Is Derived From NOI dated February 9, 2024 Incorporates Additional Information dated February 27, 2024

DAQE-IN105710049-24
Page 11

ACRONYMS

The following lists commonly used acronyms and associated translations as they apply to this document:

40 CFR Title 40 of the Code of Federal Regulations
AO Approval Order
BACT Best Available Control Technology
CAA Clean Air Act
CAAA Clean Air Act Amendments
CDS Classification Data System (used by Environmental Protection Agency to classify
sources by size/type)
CEM Continuous emissions monitor
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CO Carbon monoxide
CO2 Carbon Dioxide
CO2e Carbon Dioxide Equivalent - Title 40 of the Code of Federal Regulations Part 98,
Subpart A, Table A-1
COM Continuous opacity monitor
DAQ/UDAQ Division of Air Quality
DAQE This is a document tracking code for internal Division of Air Quality use
EPA Environmental Protection Agency
FDCP Fugitive dust control plan
GHG Greenhouse Gas(es) - Title 40 of the Code of Federal Regulations 52.21 (b)(49)(i)
GWP Global Warming Potential - Title 40 of the Code of Federal Regulations Part 86.1818-
12(a)
HAP or HAPs Hazardous air pollutant(s)
ITA Intent to Approve
LB/YR Pounds per year MACT Maximum Achievable Control Technology MMBTU Million British Thermal Units NAA Nonattainment Area NAAQS National Ambient Air Quality Standards NESHAP National Emission Standards for Hazardous Air Pollutants NOI Notice of Intent
NOx Oxides of nitrogen
NSPS New Source Performance Standard
NSR New Source Review
PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size
PSD Prevention of Significant Deterioration
PTE Potential to Emit
R307 Rules Series 307
R307-401 Rules Series 307 - Section 401
SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act
Title V Title V of the Clean Air Act
TPY Tons per year
UAC Utah Administrative Code
VOC Volatile organic compounds

The Salt Lake Tribune
Publication Name:
The Salt Lake Tribune
Publication URL:
Publication City and State:
Salt Lake City, UT
Publication County:
Salt Lake
Notice Popular Keyword Category:
Notice Keywords:
kennecott
Notice Authentication Number:
202408190932436348442
1761527914
Notice URL:
Back
Notice Publish Date:
Sunday, August 18, 2024
Notice Content
NOTICE A Notice of Intent for the following project submitted in accordance with R307-401-1, Utah Administrative Code (UAC), has been
received for consideration by the Director: Company Name: Kennecott Utah Copper LLC Location: Kennecott Utah Copper LLC - Mine &
Copperton Concentrator – 8362 West 10200 South, Bingham Canyon, UT Project Description: Rio Tinto Kennecott Utah Copper LLC
(Kennecott) operates the Coppertone Concentrator that receives the ore from the Bingham Canyon Mine, which is run through the grinding
lines and made into a slurry. Kennecott requires the use of a diesel-powered air compressor for compressed air needs and an emergency
generator to have backup power at the Concentrator in the event of a power failure. The completed engineering evaluation and air quality
impact analysis showed the proposed project meets the requirements of federal air quality regulations and the State air quality rules. The
Director intends to issue an Approval Order pending a 30-day public comment period. The project proposal, estimate of the effect on local air
quality, and draft Approval Order are available for public inspection and comment at the Utah Division of Air Quality, 195 North 1950 West,
Salt Lake City, UT 84116. Written comments received by the Division at this same address on or before September 17, 2024, will be
considered in making the final decision on the approval/disapproval of the proposed project. Email comments will also be accepted at
[e-mail]. If anyone so requests to the Director in writing within 15 days of publication of this notice, a hearing will be held in
accordance with R307-401-7, UAC. Under Section 19-1-301.5, a person who wishes to challenge a Permit Order may only raise an issue or
argument during an adjudicatory proceeding that was raised during the public comment period and was supported with sufficient information
or documentation to enable the Director to fully consider the substance and significance of the issue. Date of Notice: August 18, 2024
SLT0028947
Back

DAQE-NN105710049-24

August 15, 2024

Salt Lake Tribune and Deseret News
Legal Advertising Dept.
P.O. Box 704055
West Valley City, UT 84170
Acct #9001399880

RE: Legal Notice of Intent to Approve

This letter will confirm the authorization to publish the attached NOTICE in the Salt Lake Tribune and
Deseret News on August 18, 2024.

Please mail the invoice and affidavit of publication to the Utah State Department of Environmental
Quality, Division of Air Quality, P.O. Box 144820, Salt Lake City, Utah 84114-4820. If you have any
questions, contact Jeree Greenwood, who may be reached at [phone].

Sincerely,

{{$s }}

Jeree Greenwood
Office Technician

Enclosure

cc: Salt Lake County
cc: Wasatch Front Regional Council

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

DAQE-NN105710049-24
Page 2
NOTICE

A Notice of Intent for the following project submitted in accordance with R307-401-1, Utah
Administrative Code (UAC), has been received for consideration by the Director:

Company Name: Kennecott Utah Copper LLC
Location: Kennecott Utah Copper LLC - Mine & Copperton Concentrator – 8362 West
10200 South, Bingham Canyon, UT
Project Description: Rio Tinto Kennecott Utah Copper LLC (Kennecott) operates the Coppertone
Concentrator that receives the ore from the Bingham Canyon Mine, which is run
through the grinding lines and made into a slurry. Kennecott requires the use of a
diesel-powered air compressor for compressed air needs and an emergency
generator to have backup power at the Concentrator in the event of a power
failure.

The completed engineering evaluation and air quality impact analysis showed the proposed project meets
the requirements of federal air quality regulations and the State air quality rules. The Director intends to
issue an Approval Order pending a 30-day public comment period. The project proposal, estimate of the
effect on local air quality, and draft Approval Order are available for public inspection and comment at
the Utah Division of Air Quality, 195 North 1950 West, Salt Lake City, UT 84116. Written comments
received by the Division at this same address on or before September 17, 2024, will be considered in
making the final decision on the approval/disapproval of the proposed project. Email comments will also
be accepted at [e-mail]. If anyone so requests to the Director in writing within 15 days of
publication of this notice, a hearing will be held in accordance with R307-401-7, UAC.

Under Section 19-1-301.5, a person who wishes to challenge a Permit Order may only raise an issue or
argument during an adjudicatory proceeding that was raised during the public comment period and was
supported with sufficient information or documentation to enable the Director to fully consider the
substance and significance of the issue.

Date of Notice: August 18, 2024

{{#s=Sig_es_:signer1:signature}}

DAQE-

RN105710049 July 29, 2024 Jenny Esker
Kennecott Utah Copper LLC 4700 Daybreak Parkway South Jordan, UT 84095
[e-mail] Dear Jenny Esker,
Re: Engineer Review: Modification to Approval Order to DAQE-AN105710044-18, to Add Generators Project Number: N105710049 The DAQ requests a company representative review and sign the attached Engineer Review (ER). This ER identifies all applicable elements of the New Source Review permitting program. Kennecott Utah Copper LLC should complete this review within 10 business days of receipt. Kennecott Utah Copper LLC should contact Tad Anderson at [phone] if there are questions or concerns with the review of the draft permit conditions. Upon resolution of your concerns, please email Tad Anderson at [e-mail] the signed cover letter. Upon receipt of the signed cover letter, the DAQ will prepare an ITA for a 30-day public comment period. At the completion of the comment period, the DAQ will address any comments and will prepare an Approval Order (AO) for signature by the DAQ Director. If Kennecott Utah Copper LLC does not respond to this letter within 10 business days, the project will
move forward without source concurrence. If Kennecott Utah Copper LLC has concerns that cannot be resolved and the project becomes stagnant, the DAQ Director may issue an Order prohibiting construction. Approval Signature _____________________________________________________________ (Signature & Date)
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
Department of Environmental Quality
Kimberly D. Shelley Executive Director DIVISION OF AIR QUALITY Bryce C. Bird Director
State of Utah
SPENCER J. COX Governor DEIDRE HENDERSON Lieutenant Governor

2024.08.09
09:50:43
-06'00'

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 1
UTAH DIVISION OF AIR QUALITY
ENGINEER REVIEW

SOURCE INFORMATION
Project Number N105710049 Owner Name Kennecott Utah Copper LLC Mailing Address 4700 Daybreak Parkway
South Jordan, UT, 84095 Source Name Kennecott Utah Copper LLC- Mine & Copperton Concentrator
Source Location 8362 W 10200 S Bingham Canyon, UT 84006
UTM Projection 407,000 m Easting, 4,493,000 m Northing UTM Datum NAD27 UTM Zone UTM Zone 12 SIC Code 1021 (Copper Ores) Source Contact Jenny Esker Phone Number [phone] Email [e-mail] Billing Contact Jenny Esker Phone Number [phone]
Email [e-mail] Project Engineer Tad Anderson, Engineer
Phone Number [phone] Email [e-mail]
Notice of Intent (NOI) Submitted February 9, 2024 Date of Accepted Application April 4, 2024

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 2
SOURCE DESCRIPTION General Description
Rio Tinto Kennecott Utah Copper LLC (Kennecott) operates the Copperton Concentrator that receives the ore from the Bingham Canyon Mine which is run through the grinding lines and made into a slurry. The slurry from the ore is fed into the floatation circuits which is mixed with
reagents and aerated to float the copper from the ore and routed to the refinery to be further processed. NSR Classification: Minor Modification at Minor Source Source Classification Located in, Salt Lake City UT PM2.5 NAA, Salt Lake County SO2 NAA, Salt Lake County Airs Source Size: B Applicable Federal Standards
NSPS (Part 60), A: General Provisions NSPS (Part 60), LL: Standards of Performance for Metallic Mineral Processing Plants NSPS (Part 60), IIII: Standards of Performance for Stationary Compression Ignition Internal
Combustion Engines NSPS (Part 60), JJJJ: Standards of Performance for Stationary Spark Ignition Internal Combustion Engines
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines Title V (Part 70) Area Source Project Proposal Modification to Approval Order to DAQE-AN105710044-18, to Add Generators
Project Description Kennecott is proposing to use some of the tailings generated at the Concentrator as feed material for the Paste Plant at the Bingham Canyon Mine. Kennecott requires the use of an emergency generator (250-kW standby emergency generator, (EPA) Tier 4 certified engine) to have backup power at the Concentrator in the event of a power failure. During a power failure the materials being directed at the Paste Plant could slide back through the pipe to the Concentrator where the force of the material would present a dangerous scenario to equipment and people in the area. The
emergency generator would ensure that pumping capacity remains in place in the event of a power outage to mitigate the potential hazards.
Kennecott is also proposing to add a mobile diesel-powered air compressor unit (540-HP diesel engine, EPA Tier 4 certified engine) to meet compressed air needs at the Concentrator.
Both engines require hour limitations that have been included to the permit modification. Process Description
Ore from the Bingham Canyon Mine is stockpiled in the A-frame enclosure. The ore is fed from the enclosure to the grinding lines through the semi-autogenous grinding (SAG) mills and ball mill making the ore into slurry. The slurry is sent through cyclone clusters and the cyclone overflow is fed into the flotation circuits, and the cyclone underflow is sent to the ball mills for

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 3
further size reduction before being sent back to the cyclones and on to the flotation circuit.
In the flotation circuits, overflow is mixed with reagents and aerated to float copper and other valuable by-products from the ore. Concentrate is pumped to the existing regrinding circuit, while tailings gravity flows to a collection trench. Tailings from the collection trenches are fed to the tailings thickener feed distributor and then transported by gravity flow to the tailings impoundment for final deposition. Thickener overflow is pumped back to the process water reservoir. EMISSION IMPACT ANALYSIS Modeling is not required as R307-410-4 and R307-410-5. The emissions increase are as follows; 0.03 TPY of PM10 and PM2.5, 0.60 TPY of NOx, 4.34 TPY of CO, 1.11 TPY of SOx, 0.23 TPY of VOC, 0.05 TPY of combined HAP's. [Last updated April 3, 2024]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 4
SUMMARY OF EMISSIONS
The emissions listed below are an estimate of the total potential emissions from the source. Some rounding of emissions is possible.
Criteria Pollutant Change (TPY) Total (TPY) Ammonia 0.00 0.27 CO2 Equivalent 729.0 10914.00
Carbon Monoxide 4.34 14.21
Nitrogen Oxides 0.59 11.26
Particulate Matter - PM10 0.03 25.33
Particulate Matter - PM2.5 0.03 13.89
Sulfur Dioxide 1.11 1.21 Volatile Organic Compounds 0.23 4.27 Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Cyanide Compounds (CAS #143339) 0 100
Generic HAPs (CAS #GHAPS) 102 122
Change (TPY) Total (TPY)
Total HAPs 0.05 0.11 Note: Change in emissions indicates the difference between previous AO and proposed modification.

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 5
Review of BACT for New/Modified Emission Units 1. BACT review regarding Generator's
Emergency Generator BACT was conducted for the emergency generator engine by reviewing the RBLC. The following technologies were specified in the analysis: good combustion practices, maintenance and operating
practices, use of low-sulfur diesel fuel, compliance with applicable NSPS IIII requirements, compliance with applicable NESHAP ZZZZ requirements and the use of SCR. All of the listed control technologies are technically feasible, except for SCR. For SCR systems to function effectively, exhaust temperatures must be 200 degree C to 500 degree C to enable catalyst activation. SCR control efficiencies are low during the first 20 to 30 minutes after engines start up during maintenance and testing. There are also complications controlling the excess ammonia during the engine startup during maintenance and testing. from SCR use. SCR is not considered technically feasible for emergency units. BACT for diesel-fired emergency engines, is the following:
Good combustion, maintenance, and operating practices Use of low-sulfur diesel fuel Compliance with applicable NSPS IIII requirements
Use of a tier certified engine
Limit on hours of operation for maintenance and testing operations Compliance with applicable NESHAP ZZZZ requirements.
Diesel Air Compressor Engine BACT was conducted for diesel air compressor engine by reviewing the RBLC and CARB. The following technologies were specified in the analysis: good combustion practices, maintenance and operating practices, use of low-sulfur diesel fuel, compliance with applicable NSPS IIII requirements, compliance with applicable NESHAP ZZZZ requirements and the use of SCR. All
of the listed control technologies are technically feasible, except for SCR. For SCR systems to function effectively, exhaust temperatures must be 200 degree C to 500 degree C to enable catalyst activation. SCR control efficiencies are low during the first 20 to 30 minutes after engines start up during maintenance and testing. There are also complications controlling the excess ammonia during the engine startup during maintenance and testing. from SCR use. SCR is not considered technically feasible for the diesel air compressor engine. BACT for diesel air compressor engine, is the following:
Limiting hours of operation. Good combustion, maintenance, and operating practices
Use of low-sulfur diesel fuel Compliance with applicable NSPS IIII requirements
Use of a tier certified engine
Limit on hours of operation for maintenance and testing operations Compliance with applicable NESHAP ZZZZ requirements [Last updated April 19, 2024]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 6
SECTION I: GENERAL PROVISIONS The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):
I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in
the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101] I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]
I.3 Modifications to the equipment or processes approved by this AO that could affect the
emissions covered by this AO must be reviewed and approved. [R307-401-1] I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of two (2) years. [R307-401-8]

I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and operate any equipment approved under this AO, including associated air pollution control equipment, in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available to the Director which may include, but is not limited to, monitoring results, opacity
observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns. [R307-107] I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]

I.8 The owner/operator shall submit documentation of the status of construction or modification to the Director within 18 months from the date of this AO. This AO may become invalid if construction is not commenced within 18 months from the date of this AO or if construction is
discontinued for 18 months or more. To ensure proper credit when notifying the Director, send the documentation to the Director, attn.: NSR Section. [R307-401-18]

SECTION II: PERMITTED EQUIPMENT The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 7
II.A THE APPROVED EQUIPMENT
II.A.1 Plant Wide Copperton Concentrator
II.A.2 One (1) Feed Dryer Oil Heater Feed dryer oil heater for product molybdenite dryer Rated capacity: 5.7 MMBtu/hr Fuel type: Natural gas Product molybdenite dryer with venturi scrubber II.A.3 One (1) Product Dryer Oil Heater Product dryer oil heater* for product molybdenite dryer Rated capacity: 2.2 MMBtu/hr Fuel type: Natural gas Product: molybdenite dryer with venturi scrubber *This equipment is listed for informational purposes only. II.A.4 Molybdenite Loading Six (6) molybdenite storage bins
II.A.5 Molybdenite Storage
Two (2) molybdenite storage bins II.A.6 Two (2) Cooling Towers Closed-circuit fluid cooling tower for motors used in the grinding circuit.
II.A.7 Bag Loading
Molybdenite bag loading operations II.A.8 Cleaning System Vacuum cleaning system with baghouse

II.A.9 Ore Sorting Plant Ore sorting baghouse and sample preparation baghouse II.A.10 Metallurgical Laboratory Two (2) baghouses

II.A.11 Three (3) Pebble Crushers Pebble crushers with associated enclosed conveyors and enclosed drop points.
II.A.12 Degreasing Parts Washers
II.A.13 Four (4) Lime Silos
Controlled: bin vents

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 8
II.A.14 Three (3) Storage Tanks Capacity: 25,000 gallons (each) Contents: frother, collector, and fuel oil

II.A.15 NEW One (1) Emergency Generator Fueled: Diesel (NEW) Maximum rating: 4,357 horsepower
II.A.16 One (1) Emergency Generator
Fueled: Liquid propane-fired Maximum rating: 75 brake horsepower
II.A.17 NEW One (1) Air Compressor Engine Fueled: Diesel (NEW) Maximum rating: 540 horsepower
II.A.18 Miscellaneous Combustion Sources Natural gas-fired equipment including water heaters or comfort heaters that are each individually rated at less than 5 MMBTU/hr. This equipment is listed for informational purposes only.
II.A.19 MH Pilot Plant Feed Hopper Conveyors Baghouse on HM pilot ore treatment plant building with a control efficiency of 99%
II.A.20 Cyanide Circuit Two (2) sodium cyanide storage tanks Capacity: 8,500 gallons (each)
II.A.21 Two (2) Lime Slaker Scrubbers Type: Single stage

SECTION II: SPECIAL PROVISIONS
The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label): II.B REQUIREMENTS AND LIMITATIONS II.B.1 Plant Wide Requirements
II.B.1.a NEW Visible emissions from the following emission points shall not exceed the following values: A. Pebble crushers (subject to NSPS, Subpart LL) - 7% opacity for building exterior B. Cone crusher (subject to NSPS, Subpart LL) - 10% opacity C. Fugitive emission points (subject to NSPS, Subpart LL) - 10% opacity
D. Liquid propane (LP) emergency generator - 10% opacity

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 9
E. All other points - 10% opacity F. Baghouse on molybdenite storage bins (subject to NSPS, Subpart LL) - 7% opacity G. Diesel-fired emergency equipment - 20% opacity
Opacity observations of emissions from stationary sources shall be conducted in accordance with 40 CFR 60, Appendix A, Method 9.
For sources that are subject to NSPS, opacity shall be determined by conducting observations
in accordance with 40 CFR 60.11(b) and 40 CFR 60, Appendix A, Method 9. [40 CFR 60 Subpart LL, R307-305-3]
II.B.1.b All baghouses shall be operated as follows: A. Whenever the vacuum cleaning system is in use, all exhaust gases from the vacuum
cleaning system shall pass through the baghouse.
B. All exhaust gases from the metallurgical laboratory sample preparation hoods shall
pass through an operating baghouse. [R307-401-8] II.B.1.c The pH of the circuit using cyanide shall be maintained at a value no less than 9. [R307-401-8]
II.B.1.c.1 The pH shall be continuously monitored (+/- 0.5) in the flotation circuit upstream of the
cyanide circuit. Records shall be maintained as per Condition I.4. [R307-401-8] II.B.1.d All wet scrubbers shall comply with 40 CFR 60.384 and 60.385. [40 CFR 60 Subpart A]
II.B.1.e KUC shall use only natural gas as a primary fuel and liquid propane as a backup fuel in the dryer oil heaters and liquid propane as a fuel for the 75 hp emergency generator. [R307-401-8]
II.B.2 Roads and Fugitives
II.B.2.a To control fugitive emissions the following controls shall be applied:
A. A baghouse shall control the PM10 and PM2.5 from the MH Pilot Ore Treatment Plant. B. All copperton milling conveyors shall be partially enclosed. C. All copperton milling conveyor transfer points shall be enclosed. D. The pebble crushers shall be enclosed in a building. [R307-309, R307-401-8]

II.B.2.b Water sprays or chemical dust suppression sprays shall be installed at the following points to control fugitive emissions: A. All pebble crusher feed conveyors The sprays shall operate whenever dry conditions warrant or as determined necessary by the Director. [R307-309]
II.B.3 Generator Engine Requirements
II.B.3.a NEW KUC shall not exceed 2000 hours of operation of the diesel-fired air compressor per rolling 12-month total. [R307-401-8]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 10
II.B.3.a.1 NEW To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of diesel-fired air compressor engine shall be kept in a
log. [R307-401-8] II.B.3.a.2 NEW To determine the duration of operation, the owner/operator shall install a non-resettable hour meter for the diesel-fired air compressor engine. [R307-401-8]
II.B.3.b
NEW
The owner/operator shall not operate each emergency engine on site for more than 100 hours
per rolling 12-month period during non-emergency situations. There is no time limit on the use of the engines during emergencies. [R307-401-8]
II.B.3.b.1 NEW To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new 12-month total by the 20th day of each month using data from the previous 12 months. Records documenting the operation of each emergency engine shall be kept in a log and shall include the following:
a. The date the emergency engine was used b. The duration of operation in hours c. The reason for the emergency engine usage. [R307-401-8]
II.B.3.b.2 NEW To determine the duration of operation, the owner/operator shall install a non-resettable hour meter for each emergency engine. [R307-401-8]

II.B.3.c NEW The owner/operator shall only use diesel fuel (e.g. fuel oil #1, #2, or diesel fuel oil additives) as fuel in each emergency engine. [R307-401-8]
II.B.3.d NEW The owner/operator shall only combust diesel fuel that meets the definition of ultra-low sulfur diesel (ULSD), which has a sulfur content of 15 ppm or less. [R307-401-8]
II.B.3.d.1 NEW To demonstrate compliance with the ULSD fuel requirement, the owner/operator shall maintain records of diesel fuel purchase invoices or obtain certification of sulfur content from the diesel fuel supplier. The diesel fuel purchase invoices shall indicate that the diesel fuel meets the ULSD requirements. [R307-401-8] II.B.3.e NEW The owner/operator shall limit the use of the ventilation system generators 6-9 to the following:
a. Testing of the emergency generators shall be between 8 am and 8 pm. b. Only one (1) emergency generator shall be tested at the same time. [R307-410] II.B.4 SIP Requirement
II.B.4.a The emissions from the Product Molybdenite Dryers shall be controlled with a scrubber during operation of the dryers. [SIP Section IX.H.12]
II.B.4.a.1 During operation of the dryers, the static pressure differential between the inlet and outlet of the scrubber shall be within the Manufacturer's recommended range and shall be recorded weekly. [R307-401]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 11
II.B.4.a.2 The manometer or the differential pressure gauge shall be calibrated according to the Manufacturer's instructions at least once per year. [R307-401]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 12
PERMIT HISTORY When issued, the approval order shall supersede (if a modification) or will be based on the
following documents: Is Derived From NOI dated February 9, 2024
Supersedes DAQE-AN105710044-18 dated August 21, 2018 Incorporates Additional Information dated February 27, 2024
REVIEWER COMMENTS 1. Comment regarding Site Information: The Site Indicator (SI) number has two facilities associated with it. The Copperton Concentrator has the permit number DAQE-AN105710035-13 with the 10571 SI number. The Bingham Canyon Mine is regulated under permit number DAQE-AN105710037-15 with the 10571 SI number. These two permits have separate equipment lists and separate requirements. If the two facilities were to be combined, the source would still be considered a minor area source. The permits are held separate to keep equipment and requirements simplified. [Last updated March 15, 2024] 3. Comment regarding Emissions Factor: Engines
The PTE emissions estimates for PM10, PM2.5, NOx, VOC, and CO were generated using Tier 4 specs for gensets for PM10 and PM 2.5, NOx, CO and VOC emissions. The SOx emissions were generated using AP-42 Chapter 3. The CO2e calculated used table A-1 "Global Warming Potentials"
from 40 Code of Federal Regulations (CFR) Part 98. Both engines are limited by hours of operation (100 hours of operation for the emergency generator and 2000 hours of operation per rolling 12-month total).
[Last updated July 29, 2024] 4. Comment regarding SIP Listed Source: Kennecott is a listed source with conditions in Part H.12.g.ii of the PM2.5 Serious Nonattainment SIP. The PM2.5 Serious Nonattainment SIP has been approved by the Air Quality Board but have not been approved by Region 8 EPA. The PM2.5 Serious Nonattainment SIP conditions has been incorporated into the current appropriate AO. No additional SIP /permitting action is required for the addition of the new emergency equipment. [Last updated July 29, 2024] 5. Comment regarding SIP Kennecott is a listed source with conditions in Part H.12.g.ii of the PM2.5 Serious Nonattainment SIP. The SIP requirement pertaining to the concentrator have been included into this modification for completeness. [Last updated July 29, 2024] 6. Comment regarding Additional Information:
Additional Information was provided on February 27, 2024, updated emissions from the NOI. This data was needed for accountability and completeness for NOI to AO. [Last updated April 4, 2024]
7. Comment regarding Permit Modification, Site Analysis: This permit modification is being conducted in conjunction with a permit modification for the Bingham Canyon Mine to add equipment for underground mining operations. Both modifications
were reviewed to determine if combined increase for both modifications triggered significant emissions increase per UAC R307-101-2. Both modifications emissions increase are as follows

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 13
(tons per year): 0.44 of point source PM10, 0.26 of PM2.5, 1.28 of NOx, 7.93 of CO, 1.12 of SOx, and 0.43 of VOC. The total combined emissions increase from both modifications does not trigger
significant. [Last updated April 4, 2024] 8. Comment regarding Offset Requirements: The Kennecott, Copperton Concentrator is located in a Nonattainment area for PM10, PM2.5 and Ozone. An analysis of the emissions increases for both modifications was conducted to determine if the emissions triggered significant which would require offsetting. The analysis determined that significant was not triggered which makes this a minor modification (not a major modfiication) so offsets are not required per UAC R307-403, UAC R307-420 and UAC-R307-421. [Last updated April 4, 2024] 9. Comment regarding Kennecott Aggregation:
UDAQ has previously divided Kennecott's operations into the following separate stationary sources;
Smelter and Refinery, Central Laboratory, Tailings Impoundment, and Utah Power Plant Bingham Canyon Mine and Copperton Concentrator, and Bonneville Borrow Area Plant
These site aggregation determinations were addressed during implementation of the Title V and were separated by pollutant-emitting activities which belong to the same industrial grouping. Pollutant-emitting activities shall be considered as part of the same industrial grouping if they have the same two-digit code of the Standard Industrial Classification.
The Smelter and Refinery each have a separate AO but are combined into the same site ID 10346
and classified as a major source. The Central Laboratory, Tailings Impoundment and Utah Power Plant all have separate AOs and were historically combined into the same site ID 10572 when they were classified as a major source. When the Utah Power Plant AO was issued in 2020, site ID 10572
was no longer major source and the Title V permit was rescinded. All sites are currently minor sources. The Bingham Canyon Mine and Copperton Concentrator each have separate AOs and are combined into the same site ID 10571 and classified as a minor source (majority of PTE emissions are fugitives/tailpipe). The Bonneville Borrow Area Plant has a site ID 16035 and is classified as a minor source. To determine major source classification, fugitive emissions are counted only if the source category is a listed source category. Mining activities are not a listed source category and the fugitive
emissions are not counted towards source classification. [Last updated June 18, 2024]

Engineer Review N105710049: Kennecott Utah Copper LLC- Mine & Copperton Concentrator July 29, 2024 Page 14
ACRONYMS The following lists commonly used acronyms and associated translations as they apply to this document:
40 CFR Title 40 of the Code of Federal Regulations AO Approval Order BACT Best Available Control Technology
CAA Clean Air Act CAAA Clean Air Act Amendments CDS Classification Data System (used by EPA to classify sources by size/type) CEM Continuous emissions monitor CEMS Continuous emissions monitoring system CFR Code of Federal Regulations CMS Continuous monitoring system CO Carbon monoxide CO2 Carbon Dioxide CO2e Carbon Dioxide Equivalent - 40 CFR Part 98, Subpart A, Table A-1 COM Continuous opacity monitor
DAQ/UDAQ Division of Air Quality DAQE This is a document tracking code for internal UDAQ use EPA Environmental Protection Agency
FDCP Fugitive dust control plan GHG Greenhouse Gas(es) - 40 CFR 52.21 (b)(49)(i) GWP Global Warming Potential - 40 CFR Part 86.1818-12(a)
HAP or HAPs Hazardous air pollutant(s) ITA Intent to Approve LB/HR Pounds per hour
LB/YR Pounds per year MACT Maximum Achievable Control Technology MMBTU Million British Thermal Units
NAA Nonattainment Area NAAQS National Ambient Air Quality Standards NESHAP National Emission Standards for Hazardous Air Pollutants NOI Notice of Intent NOx Oxides of nitrogen NSPS New Source Performance Standard NSR New Source Review PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size PSD Prevention of Significant Deterioration PTE Potential to Emit
R307 Rules Series 307 R307-401 Rules Series 307 - Section 401 SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act Title V Title V of the Clean Air Act TPY Tons per year
UAC Utah Administrative Code VOC Volatile organic compounds

Rio Tinto Kennecott, 4700 Daybreak Parkway, South Jordan, Utah, 84009
December 27, 2023
Mr. Bryce Bird – Director
Utah Division of Air Quality
195 N 1950 W
Salt Lake City, UT 84116

Subject: Rio Tinto Kennecott Utah Copper LLC
Bingham Canyon Mine and Copperton Concentrator

Dear Director Bird,

On May 31, 2023, the Utah Division of Air Quality (UDAQ) sent a letter to Rio
Tinto Kennecott Utah Copper LLC (Kennecott) outlining potential impacts to the
Bingham Canyon Mine and Copperton Concentrator resulting from designation of
the Northern Wasatch Front to serious nonattainment classification in February
2025. The letter identified Kennecott’s Bingham Canyon Mine and Copperton
Concentrator as a potential major source for ozone (VOCs and NOx as
precursors). This letter outlines that the Bingham Canyon Mine and Copperton
Concentrator are not major sources under the serious nonattainament
classification.

The Bingham Canyon Mine and Copperton Concentrator are a single source for
Title V applicability, but the Copperton Concentrator operates under a separate
Approval Order from the Bingham Canyon Mine. Under R307-101, a Major
Source is defined as
“Major Source” means, to the extent provided by the federal
Clean Air Act as applicable to Title R307:
(1) any stationary source of air pollutants which emits, or has the
potential to emit, one hundred tons per year or more of any
pollutant subject to regulation under the Clean Air Act; or
. . .
(b) any source located in Salt Lake or Davis Counties or in a
nonattainment area for ozone which emits, or has the potential to
emit, VOC or nitrogen oxides in the amounts outlined in Section
182 of the federal Clean Air Act with respect to the severity of the
nonattainment area as outlined in Section 182 of the federal
Clean Air Act . . . .
Utah Admin. Code 307-101-2
Emissions of stationary sources (point sources) at the Bingham Canyon Mine and
the Copperton Concentrator are shown in Table 1. Table 1 shows that
aggregated emissions from stationary sources at the Bingham Canyon Mine and
Copperton Concentrator are below all major source thresholds and neither the
Rio Tinto Kennecott 4700 Daybreak Parkway
South Jordan, Utah
84009
Tel: [phone]

2 / 2
Bingham Canyon Mine nor Copperton Concentrator, individually or collectively,
approach any major source threshold. The Bingham Canyon Mine and Copperton
Concentrator are separate operating facilities and are therefore under separate
Approval Orders.
Table 1
Combined Emissions, Mine and Concentrator

Point Sources
at Bingham
Canyon Mine
Point Sources
at Copperton
Concentrator
Total Point
Source
Emissions
Major
Source
Thresholds
PM10 Emissions (tpy) 9.86 1.75 11.62 100
PM2.5 Emissions (tpy) 1.68 1.09 2.77 70
SO2 Emissions (tpy) 0.003 0.02 0.02 100
NOX Emissions (tpy) 2.01 6.83 8.84 50
CO Emissions (tpy) 3.97 3.36 7.33 100
VOC Emissions (tpy) 1.81 1.89 3.70 50

Based on emissions information listed in Table 1, the Bingham Canyon Mine and
Copperton Concentrator are a minor source. As it has done as part of previous
SIP planning, Kennecott will however participate in the ozone SIP process and
submit a RACT analysis for these facilities. Despite Kennecott’s participation in
the ozone SIP process, Kennecott requests that the record clearly state that the
Bingham Canyon Mine and Copperton Concentrator are minor sources.
If you have questions, please contact me at [e-mail].

Yours sincerely,

Jenny Esker Evans
Principal Advisor, Air Quality

DAQE-MN105710049-24

M E M O R A N D U M

TO: Tad Anderson, NSR Engineer

FROM: Dave Prey, Air Quality Modeler

DATE: June 13, 2024
SUBJECT: Modeling Analysis Review for the Notice of Intent for Rio Tinto Kennecott Utah Copper
LLC- Bingham Canyon Mine, Salt Lake County, Utah
_____________________________________________________________________________________
This is not a Major Prevention of Significant Deterioration (PSD) Source.
I. OBJECTIVE
Rio Tinto Kennecott Utah Copper LLC (RTK) is seeking an approval order for their Bingham
Canyon Mine (BKM) located in Salt Lake County, Utah. The BCM is an open pit mining operation
located in the southwest corner of Salt Lake County, Utah. Ore from the mine is conveyed to the
Copperton Concentrator located approximately five miles north of the open pit in Copperton, Utah
where it is ground and treated to produce copper concentrate. RTK is requesting a modification of
BCM Approval Order (AO) DAQE-AN105710047-21 to install and operate facilities associated
with underground mining operations. The underground mining operations include the use of a new
Paste Plant with two storage silos, a mixer dust collector and four emergency standby generators for
the employee ventilation systems, an emergency generator for the Paste plant, and a portable air
compressor.

This report, prepared by the Staff of the New Source Review Section (NSR), contains a review of
the air quality impact analysis (AQIA) including the information, data, assumptions and modeling
results used to determine if the facility would be in compliance with State and Federal
concentration standards.

II. APPLICABLE RULE(S)

Utah Air Quality Rules:

R307-401-6 Condition for Issuing an Approval Order
R307-410-3 Use of Dispersion Models
R307-410-4 Modeling of Criteria Pollutants in Attainment Areas

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

DP
DP
DAQE-MN105710049-24
Page 2
III. MODELING METHODOLOGY

A. Applicability

Emissions from the facility include PM10, NOx, CO, SO2, and HAPs. Modeling for NO2 and
PM10 was performed by RTK.

B. Assumptions

1. Topography/Terrain

The Plant is at an elevation 7383 feet with terrain features that have no affect on
concentration predictions.

a. Zone: 12
b. Approximate Location:

UTM (NAD83): 403633 meters East
4484086 meters North
2. Urban or Rural Area Designation

After a review of the appropriate 7.5 minute quadrangles, it was concluded the area is
“rural” for air modeling purposes.

3. Ambient Air
It was determined the Plant boundary used in the AQIA meets the State’s definition of
ambient air.

4. Building Downwash
The source was modeled with the AERMOD model. All structures at the plant were used in
the model to account for their influence on downwash.

5. Meteorology

Five (5) years of off-site surface and upper air data were used in the analysis consisting of
the following:

Surface – Herriman, UT UDAQ: 2016-2020
Upper Air – Salt Lake Airport, UT NWS: 2016-2020

6. Background

No background concentrations were needed for the Significant Impact Analysis (SIA).

7. Receptor and Terrain Elevations

The modeling domain used consisted of receptors including property boundary receptors.
This area of the state contains mountainous terrain and the modeling domain has simple and
DAQE-MN105710049-24
Page 3
complex terrain features in the near and far fields. Therefore, receptor points representing
actual terrain elevations from the area were used in the analysis.

8. Model and Options
The State-accepted AERMOD model was used to predict air pollutant concentrations under
a simple/complex terrain/wake effect situation. In quantifying concentrations, the
regulatory default option was selected.

9. Air Pollutant Emission Rates

Source
UTM Coordinates Modeled Emission Rates
Easting Northing NOx
(m) (m) (lb/hr) (tons/yr) hrs/year
PIT 403633 4484086 4.80 10.52 4380
GEN 407835 4493043 4.80 0.24 100
COMPRESS 407117 4493373 0.36 0.36 2000

Total 9.96 11.11

Source
UTM Coordinates Modeled Emission Rates
Easting Northing PM10
(m) (m) (lb/hr) (tons/yr) hrs/year
PIT 403633 4484086 0.2974 1.303 8760

Total 0.30 1.30

10. Source Location and Parameters

Source Type
Source Parameters
Elev, Ht Temp Flow Dia
(ft) (m) (ft) (K) (m/s) (m)
PIT AREA_POLY 7383.0 0.0 0.0
GEN POINT 5491.0 4.4 14.5 766 120.94 0.36
COMPRESS POINT 5629.0 1.5 5.0 800 55.29 0.17

DAQE-MN105710049-24
Page 4
IV. RESULTS AND CONCLUSIONS

A. National Ambient Air Quality Standards

The below tables provide a comparison of the predicted total air quality concentrations with the Significant Impact Levels (SIL). The predicted concentrations are less than their respective
SILs.

Air Pollutant Period Prediction Class II
Significant
Impact
Level
Background Nearby
Sources*
Total NAAQS Percent
(μg/m3) (μg/m3) (μg/m3) (μg/m3) (μg/m3) (μg/m3) SIL
NO2 1-Hour 6.6 7.5 188 88.4%

Air Pollutant Period Prediction Class II
Significant
Impact
Level
Background Nearby
Sources*
Total NAAQS Percent
(μg/m3) (μg/m3) (μg/m3) (μg/m3) (μg/m3) (μg/m3) SIL
PM10 24-Hour 0.09 5.0 150 1.9%

V. PERMIT CONDITIONS

The following suggested permit language should be included under the Terms and Conditions in the AO:
• Testing of the emergency generators shall be allowed between 8 am and 8 pm. • Only one (1) emergency generator shall be tested at the same time.

DP:jg

Emission Sources PM10 PM2.5 SOX NOX VOC CO HAP CO2e
3,250-kW Standby Generator 1.06E-02 1.06E-02 2.64E-03 2.40E-01 6.72E-02 1.25E+00 1.60E-02 2.39E+02
Diesel Air Compressor 1.79E-02 1.79E-02 1.11E+00 3.57E-01 1.67E-01 3.10E+00 3.49E-02 4.90E+02
Total Project Emissions 2.84E-02 2.84E-02 1.11E+00 5.97E-01 2.34E-01 4.34E+00 5.09E-02 7.29E+02
Current CC PTEs 25.30 13.86 0.10 10.66 4.04 9.87 0.06 10,185.00
Post-Project CC PTEs 25.33 13.89 1.21 11.26 4.27 14.21 0.11 10,913.61
PTEs taken from AO DAQE-AN105710044-18
Notes:
CC = Copperton ConcentratorCO = carbon monoxide
CO2e = carbon dioxide equivalent
HAP = hazardous air pollutantkW = kilowatt
NOx = nitrogen oxide
PM2.5 = particulate matter less than 2.5 micrometers in aerodynamic diameter
PM10 = particulate matter less than 10 micrometers in aerodynamic diameter
SOx = sulfur oxide
VOC = volatile organic compound
Potential Emissions in Tons Per Year
TABLE A-1
Potential to Emit SummaryConcentrator Thickener Project Notice of Intent Application
1 of 5
Source Type Annual Hours of
Operation Quanitity Rating (hp) Rating (kW) Fuel Use
(gal/hr)
PM10 Emissions
(tpy)
PM2.5 Emissions
(tpy)
SOX Emissions
(tpy)
NOX Emissions
(tpy)
VOC
Emissions
(tpy)
CO
Emissions
(tpy)
Total HAP
Emissions
(tpy)
Paste Plant Standby Generators 100 1 4357 3250 211.4 0.01 0.01 2.64E-03 0.24 0.07 1.25 1.60E-02Note:Engines are EPA Tier 4
GHG Emissions Calculations
Source Annual Hours of
Operation
Fuel Use
(gal/hr)
CO2 Emissions
(tpy)
CH4 Emissions
(tpy)
N2O
Emissions
(tpy)
CO2e
Emissions
(tpy)
Paste Plant Standby Generators 100 211.4 237.84 9.65E-03 1.93E-03 238.65
Notes:
Conversion 0.746 kw/hpGrams to lb conversion 0.002204624 lb/gramFuel consumption taken from manufacturer's specifications, assuming standby at 60 Hz, 100% load (pg 2, spec)
Emissions taken from rated speed nominal data versus site variation data
Assume PM10=PM2.5
Pollutant Emission Factor Units Source
PM10 0.022 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
PM2.5 0.022 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
SOx 0.000012135 lb/hp-hr AP-42 Chapter 3 Table 3.4-1
NOx 0.5 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
VOC 0.14 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kWCO 2.6 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
CO2 73.96 kg/MMBtu 40 CFR 98.33 Table C-1
CH4 0.003 kg/MMBtu 40 CFR 98.33 Table C-2
N2O 0.0006 kg/MMBtu 40 CFR 98.33 Table C-2
Diesel heat rating 0.138 MMBtu/gal 40 CFR 98.33 Table C-1Conversion 1.1023 ton/tonneSulfur content of diesel 0.0015 percent
GHG emissions are calculated using 40 CFR 98.33 Equation C-2a and C-9aDieselNet standards can be found at: https://dieselnet.com/standards/us/nonroad.php#tier4
TABLE A-2
3000kW Standby GeneratorConcentrator Thickener Project Notice of Intent Application
230510090319_f0a713eb 2 of 5
TABLE A-2
3000kW Standby GeneratorConcentrator Thickener Project Notice of Intent Application
HAP Emissions
Pollutant
AP-42 Emission
Factor
(lb/MMBtu) a
SCAQMD
Emission
Factor
(lb/MMBtu) b
SCAQMD
Emission
Factor
(lb/1000 gal)
c
Proposed
Emission
Factor
(lb/MMBtu) d
Emissions
(lbs/yr)
Emissions
(tons/yr)
Benzene 7.76E-04 1.35E-03 1.86E-01 7.76E-04 2.26E+00 1.13E-03
Toluene 2.81E-04 7.64E-04 1.05E-01 2.81E-04 8.20E-01 4.10E-04
Xylenes 1.93E-04 3.07E-04 4.24E-02 1.93E-04 5.63E-01 2.82E-04
1,3-Butadiene --1.58E-03 2.17E-01 1.58E-03 4.60E+00 2.30E-03
Formaldehyde 7.89E-05 1.25E-02 1.73E+00 7.89E-05 2.30E-01 1.15E-04
Acetaldehyde 2.52E-05 5.68E-03 7.83E-01 2.52E-05 7.35E-02 3.68E-05
Acrolein 7.88E-06 2.46E-04 3.39E-02 7.88E-06 2.30E-02 1.15E-05
Naphthalene 1.30E-04 1.43E-04 1.97E-02 1.30E-04 3.79E-01 1.90E-04
Acenaphthylene 9.23E-06 ----9.23E-06 2.69E-02 1.35E-05
Acenaphthene 4.68E-06 ----4.68E-06 1.37E-02 6.83E-06
Fluorene 1.28E-05 ----1.28E-05 3.73E-02 1.87E-05
Phenanthrene 4.08E-05 ----4.08E-05 1.19E-01 5.95E-05
Anthracene 1.23E-06 ----1.23E-06 3.59E-03 1.79E-06
Fluoranthene 4.03E-06 ----4.03E-06 1.18E-02 5.88E-06
Pyrene 3.71E-06 ----3.71E-06 1.08E-02 5.41E-06
Benzo(a)anthracene 6.22E-07 ----6.22E-07 1.81E-03 9.07E-07
Chrysene 1.53E-06 ----1.53E-06 4.46E-03 2.23E-06
Benzo(b)fluoranthene 1.11E-06 ----1.11E-06 3.24E-03 1.62E-06
Benzo(k)fluoranthene 2.18E-07 ----2.18E-07 6.36E-04 3.18E-07
Benzo(a)pyrene 2.57E-07 ----2.57E-07 7.50E-04 3.75E-07
Indeno(1,2,3-cd)pyrene 4.14E-07 ----4.14E-07 1.21E-03 6.04E-07
Dibenz(a,h)anthracene 3.46E-07 ----3.46E-07 1.01E-03 5.05E-07
Benzo(g,h,i)perylene 5.56E-07 ----5.56E-07 1.62E-03 8.11E-07
TOTAL PAH 2.12E-04 4.05E-04 5.59E-02 2.12E-04 6.18E-01 3.09E-04
Cadmium --1.09E-05 1.50E-03 1.09E-05 3.17E-02 1.59E-05
Hexavalent Chromium --7.25E-07 1.00E-04 7.25E-07 2.11E-03 1.06E-06
Arsenic --1.16E-05 1.60E-03 1.16E-05 3.38E-02 1.69E-05
Lead --6.01E-05 8.30E-03 6.01E-05 1.75E-01 8.77E-05
Nickel --2.83E-05 3.90E-03 2.83E-05 8.24E-02 4.12E-05
Ammonia f --5.80E-03 8.00E-01 5.80E-03 1.69E+01 8.46E-03
Copper --2.97E-05 4.10E-03 2.97E-05 8.67E-02 4.33E-05
Ethylbenzene --7.90E-05 1.09E-02 7.90E-05 2.30E-01 1.15E-04
Hexane --1.95E-04 2.69E-02 1.95E-04 5.69E-01 2.84E-04
Hydrogen Chloride --1.35E-03 1.86E-01 1.35E-03 3.94E+00 1.97E-03
Manganese --2.25E-05 3.10E-03 2.25E-05 6.55E-02 3.28E-05
Mercury --1.45E-05 2.00E-03 1.45E-05 4.23E-02 2.11E-05
Selenium --1.59E-05 2.20E-03 1.59E-05 4.65E-02 2.33E-05
a Emission factors from AP-42 Chapter 3, Table 3.4-3 and 3.4-4 Total 32.02 1.60E-02
b Emission factors converted from lb/1000 gallons to lb/MMBtu using the 40 CFR 98.33 default HHV of 0.138 MMBtu/Gal
d Proposed emission factors reflect the minimum emission factor between AP-42 and SCAQMD
c Emission factors from South Coast Air Quality Management District Supplemental Instructions for Reporting Procedures for
AB2588 Facilities for Reporting their Quadrennial Air Toxics Emissions Inventory, Table B-2 for Stationary and Portable Internal
Combustion Engines (http://www.aqmd.gov/docs/default-source/planning/annual-emission-reporting/supplemental-instructions-for-
ab2588-facilities.pdf?sfvrsn=12)
230510090319_f0a713eb 3 of 5
Air CompressorConcentrator Thickener Project Notice of Intent Application
Source Type Annual Hours of
Operation Quantity Rating (hp) Rating
(kW)
Fuel Use
(gal/hr)
PM10 Emissions
(tpy)
PM2.5 Emissions
(tpy)
SOX Emissions
(tpy)
NOX Emissions
(tpy)
VOC
Emissions
(tpy)
CO
Emissions
(tpy)
Total HAP
Emissions
(tpy)
Diesel Air Compressor 2000 1 540 402.84 21.7 1.79E-02 1.79E-02 1.11E+00 0.36 0.17 3.10 3.49E-02
Note:Engines are EPA Tier 4F
GHG Emissions Calculations
Source Annual Hours of
Operation
Fuel Use
(gal/hr)
CO2
Emissions
(tpy)
CH4
Emissions
(tpy)
N2O
Emissions
(tpy)
CO2e
Emissions
(tpy)
Diesel Air Compressor 2000 21.7 488.28 1.98E-02 3.96E-03 489.95
Notes:Conversion 0.746 kw/hpGrams to lb conversion 0.002204624 lb/gramAnnual hours of operation based on a conservative estimate
Assume PM10=PM2.5
Pollutant Emission Factor Units Source
PM10 0.015 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
PM2.5 0.015 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
SOx 0.00205 lb/hp-hr AP-42 Chapter 3 Table 3.3-1
NOx 0.3 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
VOC 0.14 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560CO 2.6 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
CO2 73.96 kg/MMBtu 40 CFR 98.33 Table C-1
CH4 0.003 kg/MMBtu 40 CFR 98.33 Table C-2
N2O 0.0006 kg/MMBtu 40 CFR 98.33 Table C-2
Diesel heat rating 0.138 MMBtu/gal 40 CFR 98.33 Table C-1
Conversion 1.1023 ton/tonneSulfur content of diesel 0.0015 percentGHG emissions are calculated using 40 CFR 98.33 Equation C-2a and C-9a
DieselNet standards can be found at: https://dieselnet.com/standards/us/nonroad.php#tier4
TABLE A-3
Fuel consumption taken from manufacturer's specifications, 100% load at 1670 rpm, https://www.atlascopco.com/en-us/construction-equipment/products/mobile-air-compressors-usa/large-
low-pressure-diesel-compressors/xas-1800-cd#specifications
HAP Emissions
Pollutant
AP-42 Emission
Factor
(lb/MMBtu) a
SCAQMD
Emission
Factor
(lb/MMBtu) b
SCAQMD
Emission
Factor
(lb/1000
gal) c
Proposed
Emission
Factor
(lb/MMBtu)
d
Emissions
(lbs/yr)
Emissions
(tons/yr)
Benzene 9.33E-04 1.35E-03 1.86E-01 9.33E-04 5.59E+00 2.79E-03
Toluene 4.09E-04 7.64E-04 1.05E-01 4.09E-04 2.45E+00 1.22E-03
Xylenes 2.85E-04 3.07E-04 4.24E-02 2.85E-04 1.71E+00 8.53E-04
1,3-Butadiene 3.91E-05 1.58E-03 2.17E-01 3.91E-05 2.34E-01 1.17E-04
Formaldehyde 1.18E-03 1.25E-02 1.73E+00 1.18E-03 7.07E+00 3.53E-03
Acetaldehyde 7.67E-04 5.68E-03 7.83E-01 7.67E-04 4.59E+00 2.30E-03
Acrolein 9.25E-05 2.46E-04 3.39E-02 9.25E-05 5.54E-01 2.77E-04
Naphthalene 8.48E-05 1.43E-04 1.97E-02 8.48E-05 5.08E-01 2.54E-04
Acenaphthylene 5.06E-06 ----5.06E-06 3.03E-02 1.52E-05
Acenaphthene 1.42E-06 ----1.42E-06 8.50E-03 4.25E-06
Fluorene 2.92E-05 ----2.92E-05 1.75E-01 8.74E-05
Phenanthrene 2.94E-05 ----2.94E-05 1.76E-01 8.80E-05
Anthracene 1.87E-06 ----1.87E-06 1.12E-02 5.60E-06
Fluoranthene 7.61E-06 ----7.61E-06 4.56E-02 2.28E-05
Pyrene 4.78E-06 ----4.78E-06 2.86E-02 1.43E-05
Benzo(a)anthracene 1.68E-06 ----1.68E-06 1.01E-02 5.03E-06
Chrysene 3.53E-07 ----3.53E-07 2.11E-03 1.06E-06
Benzo(b)fluoranthene 9.91E-08 ----9.91E-08 5.94E-04 2.97E-07
Benzo(k)fluoranthene 1.55E-07 ----1.55E-07 9.28E-04 4.64E-07
Benzo(a)pyrene 1.88E-07 ----1.88E-07 1.13E-03 5.63E-07
Indeno(1,2,3-cd)pyrene 3.75E-07 ----3.75E-07 2.25E-03 1.12E-06
Dibenz(a,h)anthracene 5.83E-07 ----5.83E-07 3.49E-03 1.75E-06
Benzo(g,h,i)perylene 4.89E-07 ----4.89E-07 2.93E-03 1.46E-06
TOTAL PAH 1.68E-04 4.05E-04 5.59E-02 1.68E-04 1.01E+00 5.03E-04
Cadmium --1.09E-05 1.50E-03 1.09E-05 6.51E-02 3.26E-05
Hexavalent Chromium --7.25E-07 1.00E-04 7.25E-07 4.34E-03 2.17E-06
Arsenic --1.16E-05 1.60E-03 1.16E-05 6.94E-02 3.47E-05
Lead --6.01E-05 8.30E-03 6.01E-05 3.60E-01 1.80E-04
Nickel --2.83E-05 3.90E-03 2.83E-05 1.69E-01 8.46E-05
Ammonia f --5.80E-03 8.00E-01 5.80E-03 3.47E+01 1.74E-02
Copper --2.97E-05 4.10E-03 2.97E-05 1.78E-01 8.90E-05
Ethylbenzene --7.90E-05 1.09E-02 7.90E-05 4.73E-01 2.37E-04
Hexane --1.95E-04 2.69E-02 1.95E-04 1.17E+00 5.84E-04
Hydrogen Chloride --1.35E-03 1.86E-01 1.35E-03 8.09E+00 4.04E-03
Manganese --2.25E-05 3.10E-03 2.25E-05 1.35E-01 6.73E-05
Mercury --1.45E-05 2.00E-03 1.45E-05 8.68E-02 4.34E-05
Selenium --1.59E-05 2.20E-03 1.59E-05 9.55E-02 4.77E-05
a Emission factors from AP-42 Chapter 3, Table 3.3-2 Total 69.82 3.49E-02
b Emission factors converted from lb/1000 gallons to lb/MMBtu using the 40 CFR 98.33 de 0.138 MMBtu/Gal
d Proposed emission factors reflect the minimum emission factor between AP-42 and SCAQMD
c Emission factors from South Coast Air Quality Management District Supplemental Instructions for Reporting
Procedures for AB2588 Facilities for Reporting their Quadrennial Air Toxics Emissions Inventory, Table B-2 for
Stationary and Portable Internal Combustion Engines (http://www.aqmd.gov/docs/default-source/planning/annual-
emission-reporting/supplemental-instructions-for-ab2588-facilities.pdf?sfvrsn=12)
Rio Tinto Kennecott, 4700 Daybreak Parkway, South Jordan, Utah, 84009
February 9, 2024
Mr. Bryce Bird – Director Environmental Engineer, Air Quality Policy Section Utah Division of Air Quality 195 N 1950 W Salt Lake City, UT 84116
Subject: Rio Tinto Kennecott Utah Copper Notice of Intent Application for Copperton Concentrator
Dear Mr. Bird,
Rio Tinto Kennecott Utah Copper LLC (Kennecott) is submitting this Notice of Intent (NOI) application to modify Copperton Concentrator Approval Order (AO) DAQE-AN105710044-18. Kennecott is proposing to install and operate a new 3,250-kilowatt (kW) generator for emergency use at the Concentrator and a mobile 540-horsepower (HP) diesel-powered air compressor as support equipment.
Process Description
Kennecott is proposing to use some of the tailings generated at the Concentrator as feed material for the Paste Plant at the Bingham Canyon Mine. It is necessary to have backup power at the Concentrator as in the event of a power failure, the materials being directed to the Paste Plant could slide back through the pipe to the Concentrator where the force of the material would present a dangerous scenario to equipment and people in the area. The emergency generator would ensure that pumping capacity
remains in place in the event of a power outage to mitigate the potential hazards.
Additionally, Kennecott is proposing to add a mobile diesel-powered air compressor unit to meet
compressed air needs at the Concentrator.
Emissions Information
Emergency Standby Generator
Emissions will be generated during testing and maintenance of the 3,250-kW standby emergency generator. The generator will be equipped with a U.S. Environmental Protection Agency (EPA) Tier 4 certified engine. The hours of operation for the generator will be limited to 100 hours per year for routine testing and maintenance purposes. Emissions are estimated using DieselNet Tier 4 emissions standards. Emissions of sulfur oxide (SOX) are estimated using factors from AP-42 Fifth Edition, Section 3.4, Table 3.4-1 (EPA 1996) and assuming the use of ultra-low sulfur diesel with a maximum sulfur content of 0.0015 percent by weight. Emissions of hazardous air pollutants are estimated using a combination of emission factors from AP-42 Fifth Edition, Section 3.4, Tables 3.4-3 and 3.4-4 (EPA 1996) and Supplemental Instructions for Reporting Procedures for AB2588 Facilities for Reporting their Quadrennial
Air Toxics Emission Inventory, Table B-2 for Stationary and Portable Internal Combustion Engines (South Coast Air Quality Management District 2016). Greenhouse gas emissions are estimated using the methodology outlined in 40 Code of Federal Regulations (CFR) 98.33, Equations C-2a and C-9a.
Proposed project emissions are summarized in Table 1. The emissions calculations are included in Attachment A.
Rio Tinto Kennecott 4700 Daybreak Parkway South Jordan, Utah 84009 Tel: [phone]
2 / 3
Diesel Air Compressor
Emissions will be generated during use of the air compressor, specifically a 540-HP diesel engine. The air compressor will be equipped with an EPA Tier 4 certified engine. The hours of operation for the generators will be limited to 2,000 hours per year. Emissions are estimated using DieselNet Tier 4 emissions standards. Emissions of SOX are estimated using the methodology from AP-42 Fifth Edition, Section 3.3, Table 3.3-1 (EPA 1996) and assuming the use of ultra-low sulfur diesel with a maximum sulfur content of 0.0015 percent by weight. Emissions of hazardous air pollutants are estimated using a combination of emission factors from AP-42 Fifth Edition, Section 3.3, Tables 3.3-2 (EPA 1996) and Supplemental Instructions for Reporting Procedures for AB2588 Facilities for Reporting their Quadrennial
Air Toxics Emission Inventory, Table B-2 for Stationary and Portable Internal Combustion Engines (South Coast Air Quality Management District 2016). Greenhouse gas emissions are estimated using the methodology outlined in 40 CFR 98.33, Equations C-2a and C-9a.
Proposed project emissions are summarized in Table 1. The emissions calculations are included in Attachment A.
Table 1. Summary of Proposed Project Emissions
Potential Emissions in Tons Per Year
Source PM10 PM2.5 SOX NOX VOC CO HAP CO2e
3,250-kW
Emergency Standby
Generator
1.06E-
02
1.06E-02 2.64E-03 2.40E-
01
6.72E-
02
1.25E+00 1.60E-
02
2.39E+02
Diesel Air
Compressor
1.79E-
02
1.79E-02 1.11E+00 3.57E-
01
1.67E-
01
3.10E+00 3.49E-
02
4.90E+02
Total Project
Emissions
1.06E-
02
1.06E-02 2.64E-03 2.40E-
01
6.72E-
02
1.25E+00 1.60E-
02
2.39E+02
Notes: CO = carbon monoxide CO2e = carbon dioxide equivalent HAP = hazardous air pollutant NOx = nitrogen oxide PM2.5 = particulate matter less than 2.5 micrometers in diameter PM10 = particulate matter less than 10 micrometers in diameter SOx = sulfur oxides VOC = volatile organic compound Best Available Control Technology Analyses
As required by Utah Administrative Code (UAC) R307-401-8(1)(a), the Director will issue an AO if it is determined through plan review that the following condition has been met: the degree of pollution control for emissions, to include fugitive emissions and fugitive dust, is at least best available control technology (BACT) except as otherwise provided in UAC R307. Utah has adopted the emissions control BACT process described in 40 CFR 52.21(j) and incorporated by reference into UAC R307-405-11.
BACT Analysis for Emergency Standby Generator
Combustion of diesel fuel from the use of the emergency standby generators will generate emissions. The following presents a BACT analysis for the proposed standby generators:
 Step 1—Identify All Control Technologies. Potential emission control technologies identified in the RACT/BACT/LAER Clearinghouse (RBLC) and California Air Resources Board (CARB) for similar-sized diesel standby generators include implementing good combustion practices, limiting hours of operation, and limiting the sulfur content of diesel fuel to 0.0015 percent. Certification and compliance with applicable New Source Performance Standards are acceptable means of demonstrating BACT for emergency generators.
3 / 3
 Step 2—Eliminate Technically Infeasible Options. Not applicable as all identified control technologies are technically feasible.
 Step 3 and Step 4—Rank Remaining Control Technologies by Control Effectiveness and Evaluate
Most Effective Controls and Document Results. Complying with 40 CFR Subpart IIII requirements, implementing good combustion practices, limiting hours of operation, and using ultra-low sulfur diesel are effective BACT in minimizing emissions from these sources.
 Step 5—Select BACT. Complying with 40 CFR Subpart IIII requirements and NSPS standards, implementing good combustion practices, limiting hours of operation to no more than 100 hours, and limiting the sulfur content of fuel to 0.0015 percent, are identified as BACT for the emergency standby diesel generators.
BACT Analysis for Diesel Air Compressor
Combustion of diesel fuel from the use of the diesel air compressors will generate emissions. The following presents a BACT analysis for the proposed air compressor:
 Step 1—Identify All Control Technologies. Potential emission control technologies identified in the RBLC and CARB for similar-sized diesel engines include implementing good combustion practices and limiting hours of operation. Certification and compliance with applicable New Source Performance Standards are acceptable means of demonstrating BACT for diesel air compressors.
 Step 2—Eliminate Technically Infeasible Options. Not applicable as all identified control technologies are technically feasible.
 Step 3 and Step 4—Rank Remaining Control Technologies by Control Effectiveness and Evaluate Most Effective Controls and Document Results. Complying with 40 CFR Subpart IIII requirements, implementing good combustion practices, and limiting hours of operation are effective BACT in minimizing emissions from these sources.
 Step 5—Select BACT. Complying with 40 CFR Subpart IIII requirements and NSPS standards and implementing good combustion practices are identified as BACT for diesel-powered air compressors.
Kennecott looks forward to working with the Utah Division of Air Quality on this NOI application. Should you have any questions, please feel free to contact me at [phone].
Yours sincerely,

Jenny Esker Principal Advisor, Air Quality Permitting and Compliance
Attachment A
Emissions Calculations
Emission Sources PM10 PM2.5 SOX NOX VOC CO HAP CO2e
3,250-kW Standby Generator 1.06E-02 1.06E-02 2.64E-03 2.40E-01 6.72E-02 1.25E+00 1.60E-02 2.39E+02
Diesel Air Compressor 1.79E-02 1.79E-02 1.11E+00 3.57E-01 1.67E-01 3.10E+00 3.49E-02 4.90E+02
Total Project Emissions 1.06E-02 1.06E-02 2.64E-03 2.40E-01 6.72E-02 1.25E+00 1.60E-02 2.39E+02
Current CC PTEs 25.30 13.86 0.10 10.66 4.04 9.87 0.06 10,185.00
Post-Project CC PTEs 25.31 13.87 0.10 10.90 4.11 11.12 0.08 10,423.65
PTEs taken from AO DAQE-AN105710044-18
Notes:
CC = Copperton ConcentratorCO = carbon monoxide
CO2e = carbon dioxide equivalent
HAP = hazardous air pollutant
kW = kilowatt
NOx = nitrogen oxide
PM2.5 = particulate matter less than 2.5 micrometers in aerodynamic diameter
PM10 = particulate matter less than 10 micrometers in aerodynamic diameter
SOx = sulfur oxide
VOC = volatile organic compound
Potential Emissions in Tons Per Year
TABLE A-1
Potential to Emit SummaryConcentrator Thickener Project Notice of Intent Application
1 of 1
Source Type Annual Hours of
Operation Quanitity Rating (hp) Rating (kW) Fuel Use
(gal/hr)
PM10 Emissions (tpy)
PM2.5 Emissions (tpy)
SOX Emissions (tpy)
NOX Emissions (tpy)
VOC
Emissions
(tpy)
CO
Emissions
(tpy)
Total HAP
Emissions
(tpy)Paste Plant Standby Generators 100 1 4357 3250 211.4 0.01 0.01 2.64E-03 0.24 0.07 1.25 1.60E-02Note:Engines are EPA Tier 4
GHG Emissions Calculations
Source Annual Hours of
Operation
Fuel Use
(gal/hr)
CO2
Emissions
(tpy)
CH4
Emissions
(tpy)
N2O
Emissions
(tpy)
CO2e
Emissions
(tpy)Paste Plant Standby Generators 100 211.4 237.84 9.65E-03 1.93E-03 238.65
Notes:Conversion 0.746 kw/hpGrams to lb conversion 0.002204624 lb/gramFuel consumption taken from manufacturer's specifications, assuming standby at 60 Hz, 100% load (pg 2, spec)Emissions taken from rated speed nominal data versus site variation data
Assume PM10=PM2.5
Pollutant Emission Factor Units Source
PM10 0.022 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
PM2.5 0.022 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
SOx 0.000012135 lb/hp-hr AP-42 Chapter 3 Table 3.4-1
NOx 0.5 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
VOC 0.14 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
CO 2.6 g/bhp-hr DieselNet Tier 4 specs for gensets >2015, >560kW
CO2 73.96 kg/MMBtu 40 CFR 98.33 Table C-1
CH4 0.003 kg/MMBtu 40 CFR 98.33 Table C-2
N2O 0.0006 kg/MMBtu 40 CFR 98.33 Table C-2
Diesel heat rating 0.138 MMBtu/gal 40 CFR 98.33 Table C-1Conversion 1.1023 ton/tonneSulfur content of diesel 0.0015 percentGHG emissions are calculated using 40 CFR 98.33 Equation C-2a and C-9aDieselNet standards can be found at: https://dieselnet.com/standards/us/nonroad.php#tier4
TABLE A-2
3000kW Standby Generator
Concentrator Thickener Project Notice of Intent Application
230510090319_f0a713eb 1 of 2
TABLE A-2
3000kW Standby Generator
Concentrator Thickener Project Notice of Intent Application
HAP Emissions
Pollutant
AP-42 Emission
Factor
(lb/MMBtu) a
SCAQMD
Emission
Factor
(lb/MMBtu) b
SCAQMD Emission
Factor (lb/1000 gal)
c
Proposed
Emission
Factor
(lb/MMBtu) d
Emissions
(lbs/yr)
Emissions
(tons/yr)
Benzene 7.76E-04 1.35E-03 1.86E-01 7.76E-04 2.26E+00 1.13E-03
Toluene 2.81E-04 7.64E-04 1.05E-01 2.81E-04 8.20E-01 4.10E-04
Xylenes 1.93E-04 3.07E-04 4.24E-02 1.93E-04 5.63E-01 2.82E-04
1,3-Butadiene --1.58E-03 2.17E-01 1.58E-03 4.60E+00 2.30E-03
Formaldehyde 7.89E-05 1.25E-02 1.73E+00 7.89E-05 2.30E-01 1.15E-04
Acetaldehyde 2.52E-05 5.68E-03 7.83E-01 2.52E-05 7.35E-02 3.68E-05
Acrolein 7.88E-06 2.46E-04 3.39E-02 7.88E-06 2.30E-02 1.15E-05
Naphthalene 1.30E-04 1.43E-04 1.97E-02 1.30E-04 3.79E-01 1.90E-04
Acenaphthylene 9.23E-06 ----9.23E-06 2.69E-02 1.35E-05
Acenaphthene 4.68E-06 ----4.68E-06 1.37E-02 6.83E-06
Fluorene 1.28E-05 ----1.28E-05 3.73E-02 1.87E-05
Phenanthrene 4.08E-05 ----4.08E-05 1.19E-01 5.95E-05
Anthracene 1.23E-06 ----1.23E-06 3.59E-03 1.79E-06
Fluoranthene 4.03E-06 ----4.03E-06 1.18E-02 5.88E-06
Pyrene 3.71E-06 ----3.71E-06 1.08E-02 5.41E-06
Benzo(a)anthracene 6.22E-07 ----6.22E-07 1.81E-03 9.07E-07
Chrysene 1.53E-06 ----1.53E-06 4.46E-03 2.23E-06
Benzo(b)fluoranthene 1.11E-06 ----1.11E-06 3.24E-03 1.62E-06
Benzo(k)fluoranthene 2.18E-07 ----2.18E-07 6.36E-04 3.18E-07
Benzo(a)pyrene 2.57E-07 ----2.57E-07 7.50E-04 3.75E-07
Indeno(1,2,3-cd)pyrene 4.14E-07 ----4.14E-07 1.21E-03 6.04E-07
Dibenz(a,h)anthracene 3.46E-07 ----3.46E-07 1.01E-03 5.05E-07
Benzo(g,h,i)perylene 5.56E-07 ----5.56E-07 1.62E-03 8.11E-07
TOTAL PAH 2.12E-04 4.05E-04 5.59E-02 2.12E-04 6.18E-01 3.09E-04
Cadmium --1.09E-05 1.50E-03 1.09E-05 3.17E-02 1.59E-05
Hexavalent Chromium --7.25E-07 1.00E-04 7.25E-07 2.11E-03 1.06E-06
Arsenic --1.16E-05 1.60E-03 1.16E-05 3.38E-02 1.69E-05
Lead --6.01E-05 8.30E-03 6.01E-05 1.75E-01 8.77E-05
Nickel --2.83E-05 3.90E-03 2.83E-05 8.24E-02 4.12E-05
Ammonia f --5.80E-03 8.00E-01 5.80E-03 1.69E+01 8.46E-03
Copper --2.97E-05 4.10E-03 2.97E-05 8.67E-02 4.33E-05
Ethylbenzene --7.90E-05 1.09E-02 7.90E-05 2.30E-01 1.15E-04
Hexane --1.95E-04 2.69E-02 1.95E-04 5.69E-01 2.84E-04
Hydrogen Chloride --1.35E-03 1.86E-01 1.35E-03 3.94E+00 1.97E-03
Manganese --2.25E-05 3.10E-03 2.25E-05 6.55E-02 3.28E-05
Mercury --1.45E-05 2.00E-03 1.45E-05 4.23E-02 2.11E-05
Selenium --1.59E-05 2.20E-03 1.59E-05 4.65E-02 2.33E-05a Emission factors from AP-42 Chapter 3, Table 3.4-3 and 3.4-4 Total 32.02 1.60E-02
b Emission factors converted from lb/1000 gallons to lb/MMBtu using the 40 CFR 98.33 default HHV of 0.138 MMBtu/Gal
d Proposed emission factors reflect the minimum emission factor between AP-42 and SCAQMD
c Emission factors from South Coast Air Quality Management District Supplemental Instructions for Reporting Procedures for AB2588 Facilities for Reporting their Quadrennial Air Toxics Emissions Inventory, Table B-2 for Stationary and Portable Internal Combustion Engines (http://www.aqmd.gov/docs/default-source/planning/annual-emission-reporting/supplemental-instructions-for-ab2588-facilities.pdf?sfvrsn=12)
230510090319_f0a713eb 2 of 2
Air CompressorConcentrator Thickener Project Notice of Intent Application
Source Type Annual Hours of Operation Quantity Rating (hp) Rating (kW) Fuel Use (gal/hr)
PM10 Emissions
(tpy)
PM2.5 Emissions
(tpy)
SOX Emissions
(tpy)
NOX Emissions
(tpy)
VOC
Emissions
(tpy)
CO
Emissions
(tpy)
Total HAP
Emissions
(tpy)
Diesel Air Compressor 2000 1 540 402.84 21.7 1.79E-02 1.79E-02 1.11E+00 0.36 0.17 3.10 3.49E-02Note:Engines are EPA Tier 4F
GHG Emissions Calculations
Source Annual Hours of
Operation
Fuel Use
(gal/hr)
CO2 Emissions
(tpy)
CH4 Emissions
(tpy)
N2O
Emissions
(tpy)
CO2e
Emissions
(tpy)Diesel Air Compressor 2000 21.7 488.28 1.98E-02 3.96E-03 489.95
Notes:Conversion 0.746 kw/hpGrams to lb conversion 0.002204624 lb/gram
Annual hours of operation based on a conservative estimate
Assume PM10=PM2.5
Pollutant Emission Factor Units Source
PM10 0.015 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
PM2.5 0.015 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
SOx 0.00205 lb/hp-hr AP-42 Chapter 3 Table 3.3-1
NOx 0.3 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
VOC 0.14 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560CO 2.6 g/bhp-hr DieselNet Tier 4 specs for units 130 <= kW <= 560
CO2 73.96 kg/MMBtu 40 CFR 98.33 Table C-1
CH4 0.003 kg/MMBtu 40 CFR 98.33 Table C-2
N2O 0.0006 kg/MMBtu 40 CFR 98.33 Table C-2
Diesel heat rating 0.138 MMBtu/gal 40 CFR 98.33 Table C-1
Conversion 1.1023 ton/tonne
Sulfur content of diesel 0.0015 percentGHG emissions are calculated using 40 CFR 98.33 Equation C-2a and C-9aDieselNet standards can be found at: https://dieselnet.com/standards/us/nonroad.php#tier4
TABLE A-3
Fuel consumption taken from manufacturer's specifications, 100% load at 1670 rpm, https://www.atlascopco.com/en-us/construction-equipment/products/mobile-air-compressors-usa/large-low-pressure-diesel-compressors/xas-1800-cd#specifications
HAP Emissions
Pollutant
AP-42 Emission
Factor
(lb/MMBtu) a
SCAQMD
Emission Factor
(lb/MMBtu) b
SCAQMD
Emission Factor
(lb/1000
gal) c
Proposed
Emission Factor
(lb/MMBtu)
d
Emissions
(lbs/yr)
Emissions
(tons/yr)
Benzene 9.33E-04 1.35E-03 1.86E-01 9.33E-04 5.59E+00 2.79E-03
Toluene 4.09E-04 7.64E-04 1.05E-01 4.09E-04 2.45E+00 1.22E-03
Xylenes 2.85E-04 3.07E-04 4.24E-02 2.85E-04 1.71E+00 8.53E-04
1,3-Butadiene 3.91E-05 1.58E-03 2.17E-01 3.91E-05 2.34E-01 1.17E-04
Formaldehyde 1.18E-03 1.25E-02 1.73E+00 1.18E-03 7.07E+00 3.53E-03
Acetaldehyde 7.67E-04 5.68E-03 7.83E-01 7.67E-04 4.59E+00 2.30E-03
Acrolein 9.25E-05 2.46E-04 3.39E-02 9.25E-05 5.54E-01 2.77E-04
Naphthalene 8.48E-05 1.43E-04 1.97E-02 8.48E-05 5.08E-01 2.54E-04
Acenaphthylene 5.06E-06 ----5.06E-06 3.03E-02 1.52E-05
Acenaphthene 1.42E-06 ----1.42E-06 8.50E-03 4.25E-06
Fluorene 2.92E-05 ----2.92E-05 1.75E-01 8.74E-05
Phenanthrene 2.94E-05 ----2.94E-05 1.76E-01 8.80E-05
Anthracene 1.87E-06 ----1.87E-06 1.12E-02 5.60E-06
Fluoranthene 7.61E-06 ----7.61E-06 4.56E-02 2.28E-05
Pyrene 4.78E-06 ----4.78E-06 2.86E-02 1.43E-05
Benzo(a)anthracene 1.68E-06 ----1.68E-06 1.01E-02 5.03E-06
Chrysene 3.53E-07 ----3.53E-07 2.11E-03 1.06E-06
Benzo(b)fluoranthene 9.91E-08 ----9.91E-08 5.94E-04 2.97E-07
Benzo(k)fluoranthene 1.55E-07 ----1.55E-07 9.28E-04 4.64E-07
Benzo(a)pyrene 1.88E-07 ----1.88E-07 1.13E-03 5.63E-07
Indeno(1,2,3-cd)pyrene 3.75E-07 ----3.75E-07 2.25E-03 1.12E-06
Dibenz(a,h)anthracene 5.83E-07 ----5.83E-07 3.49E-03 1.75E-06
Benzo(g,h,i)perylene 4.89E-07 ----4.89E-07 2.93E-03 1.46E-06
TOTAL PAH 1.68E-04 4.05E-04 5.59E-02 1.68E-04 1.01E+00 5.03E-04
Cadmium --1.09E-05 1.50E-03 1.09E-05 6.51E-02 3.26E-05
Hexavalent Chromium --7.25E-07 1.00E-04 7.25E-07 4.34E-03 2.17E-06
Arsenic --1.16E-05 1.60E-03 1.16E-05 6.94E-02 3.47E-05
Lead --6.01E-05 8.30E-03 6.01E-05 3.60E-01 1.80E-04
Nickel --2.83E-05 3.90E-03 2.83E-05 1.69E-01 8.46E-05
Ammonia f --5.80E-03 8.00E-01 5.80E-03 3.47E+01 1.74E-02
Copper --2.97E-05 4.10E-03 2.97E-05 1.78E-01 8.90E-05
Ethylbenzene --7.90E-05 1.09E-02 7.90E-05 4.73E-01 2.37E-04
Hexane --1.95E-04 2.69E-02 1.95E-04 1.17E+00 5.84E-04
Hydrogen Chloride --1.35E-03 1.86E-01 1.35E-03 8.09E+00 4.04E-03
Manganese --2.25E-05 3.10E-03 2.25E-05 1.35E-01 6.73E-05
Mercury --1.45E-05 2.00E-03 1.45E-05 8.68E-02 4.34E-05
Selenium --1.59E-05 2.20E-03 1.59E-05 9.55E-02 4.77E-05a Emission factors from AP-42 Chapter 3, Table 3.3-2 Total 69.82 3.49E-02b Emission factors converted from lb/1000 gallons to lb/MMBtu using the 40 CFR 98.33 de 0.138 MMBtu/Gal
d Proposed emission factors reflect the minimum emission factor between AP-42 and SCAQMD
c Emission factors from South Coast Air Quality Management District Supplemental Instructions for Reporting Procedures for AB2588 Facilities for Reporting their Quadrennial Air Toxics Emissions Inventory, Table B-2 for Stationary and Portable Internal Combustion Engines (http://www.aqmd.gov/docs/default-source/planning/annual-emission-reporting/supplemental-instructions-for-ab2588-facilities.pdf?sfvrsn=12)