DAQ-2024-008611

DAQE-AN103670030-24

{{$d1 }}

Stewart Hogan
Asahi Refining USA, Incorporated
4601 West 2100 South
West Valley City, UT 84120
[e-mail]

Dear Mr. Hogan:

Re: Approval Order: Administrative Amendment to Approval Order DAQE-AN103670029-24 to
Replace a Melt Furnace under R307-401-12
Project Number: N103670030

The attached Approval Order (AO) is issued pursuant to the Notice of Intent (NOI) received on May 28,
2024. Asahi Refining USA, Incorporated must comply with the requirements of this AO, all applicable
state requirements (R307), and Federal Standards.

The project engineer for this action is Christine Bodell, 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:CB:jg

cc: Salt Lake County Health Department

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

June 26, 2024

STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

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APPROVAL ORDER
DAQE-AN103670030-24
Administrative Amendment to Approval Order
DAQE-AN103670029-24 to Replace a Melt Furnace under
R307-401-12

Prepared By
Christine Bodell, Engineer
[phone]
[e-mail]

Issued to
Asahi Refining USA, Incorporated - Precious Metals Refinery

Issued On
{{$d2 }}

Issued By

{{$s }}

Bryce C. Bird
Director
Division of Air Quality
June 26, 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 .................................................................................... 4
SECTION II: PERMITTED EQUIPMENT .............................................................................. 5
SECTION II: SPECIAL PROVISIONS ..................................................................................... 7
PERMIT HISTORY ................................................................................................................... 11
ACRONYMS ............................................................................................................................... 12

DAQE-AN103670030-24
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
Asahi Refining USA, Incorporated Asahi Refining USA, Incorporated - Precious
Metals Refinery

Mailing Address Physical Address
4601 West 2100 South 4601 West 2100 South
West Valley City, UT 84120 West Valley City, UT 84120

Source Contact UTM Coordinates
Name: Stewart Hogan 415,495 m Easting
Phone: [phone],508,700 m Northing
Email: [e-mail] Datum NAD83
UTM Zone 12

SIC code 3339 (Primary Smelting & Refining of Nonferrous Metals, Except Copper & Aluminum)

SOURCE INFORMATION
General Description
Asahi Refining USA, Incorporated (Asahi) currently operates a precious metals refinery in West Valley
City, Salt Lake County. Mined doré and scrap are melted and tested for purity using small electric
induction furnaces, and then separated depending on gold and silver content. Separation is achieved by
using various inorganic chemicals and electrolytic methods. Silver is poured into anode molds and then
placed into the electrolytic cells. The cells contain silver nitrate solution, and the low voltage current
causes silver crystals to form onto a cathode plate. The silver crystal is scraped off and collected.

NSR Classification
Administrative Amendment

Source Classification
Located in Northern Wasatch Front O3 NAA, Salt Lake City UT PM2.5 NAA, Salt Lake County SO2
NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
MACT (Part 63), A: General Provisions
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines
DAQE-AN103670030-24
Page 4

Project Description
Asahi is currently permitted to operate three (3) natural gas-fueled melt furnaces, each rated less than 5
MMBtu/hr (see Approval Order DAQE-AN103670029-24, Equipment ID II.A.14). Asahi will be
replacing one (1) melt furnace with one (1) electric tilt furnace. The new and existing electric tilt furnaces
(see Approval Order DAQE-AN103670029-24, Equipment ID II.A.15) use the same control technologies
as the melt furnaces: a nanofilter baghouse made by UAS or the combination of the venturi scrubber,
WESP II, and scrubber #359.

Asahi is not requesting to increase any production and/or operational limits. No emissions are increasing.
This project meets the requirements of UAC R307-401-12 Reduction in Air Pollutants and does not
require a public comment period.

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 0.06
CO2 Equivalent 0 994.70
Carbon Monoxide 0 0.73
Lead 0 0.01
Nitrogen Oxides 0 4.31
Particulate Matter - PM10 0 2.01
Particulate Matter - PM2.5 0 2.01
Sulfur Dioxide 0 6.11
Volatile Organic Compounds 0 0.09

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Chlorine (CAS #7782505) 0 800
Hexane (CAS #110543) 0 20
Hydrochloric Acid (Hydrogen Chloride) (CAS #7647010) 0 1600
Lead (CAS #7439921) 0 20
Selenium & Compounds (CAS #253) 0 60
Change (TPY) Total (TPY)
Total HAPs 0 1.25

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]

DAQE-AN103670030-24
Page 5

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 Metal Refinery
Precious Metals Refinery Plant.

II.A.2 Wastewater Treatment
Wastewater effluent treatment. Process controlled by scrubber #760.

II.A.3 Electrolytic Cells
Silver electrolytic cell (refining of silver). Process controlled by scrubber #761.

II.A.4 Electrolytic Cells
Gold electrolytic cell (refining of gold). Process controlled by scrubber #359.

II.A.5 Wet Circuit
Gold refinery wet circuits (part of the gold refining process). Process controlled by scrubber
#359.

DAQE-AN103670030-24
Page 6

II.A.6 Chlorination
Gold chloride electrolytic production (refining of gold). Process controlled by scrubber #359.

II.A.7 Slime Washing
Silver anode slime washing process (recovery of gold). Process controlled by scrubber #248.

II.A.8 Wet Chlorides Treatment
Hydrometallurgical process for silver chloride sludge processing (recovery of gold). Controlled
by scrubber #359.

II.A.9 Fabric-Filter Baghouse
Four (4) fabric-filter baghouses

One (1) baghouse controls emissions from the sweep preparation process. Two (2) baghouses
control emissions from the melt room furnaces, the electric tilt furnaces, and the electric push -out
furnaces. One (1) baghouse controls the ashing furnace (Item II.A.26).

II.A.10 Boiler
One (1) boiler, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.11 Dust Collector
Dust collector for welding fume and grinding dust control in maintenance shop.

II.A.12 Electrostatic Precipitator
One (1) wet-electrostatic precipitator (ID: WESP II).

II.A.13 Chlorination Furnaces
Four (4) electric-induction chlorination furnaces. Process controlled by venturi scrubber, WESP
II, and scrubber #359.

II.A.14 Melt Furnaces
Two (2) melt-room furnaces, natural gas-fueled, rated less than 5 MMBtu/hr each. Process
controlled by a nanofilter baghouse made by UAS or the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.15 Tilt Furnaces (One (1) New)
Eight (8) electric-tilt furnaces. Process controlled by a nanofilter baghouse made by UAS or the
combination of the venturi scrubber, WESP II, and scrubber #359.

II.A.16 Push-out Furnaces
Four (4) electric push-out furnaces. Process controlled by baghouse or the combination of the
venturi scrubber, WESP II, and scrubber #359.

II.A.17 Emergency Generator Engine
One (1) emergency power generator engine, natural gas-fueled, rated at 60 kW.

II.A.18 Combustion Afterburner
One (1) incinerator, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.19 Nitrate Plant
Silver nitrate plant (recovery of silver). Process controlled by scrubber #248.

II.A.20 Slime Plant
Slime plant (recovery of gold). Process controlled by scrubber #248.

DAQE-AN103670030-24
Page 7

II.A.21 Drying Cabinets
Five (5) electric drying cabinets. Process controlled by the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.22 Drying Cabinet
One (1) drying cabinet, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.23 Wet Scrubbers
Four (4) packed bed wet scrubbers (ID: 760, 359, 248, 761).

II.A.24 Venturi Scrubber
One (1) venturi scrubber attached to WESP II as a pre-scrubber.

II.A.25 Tank System
Silver reduction tanks (recovery of silver). Process controlled by scrubber #248.

II.A.26 Ashing Furnace
One (1) dental scrap ashing furnace. Process controlled by baghouse (Item II.A.9) and activated
carbon adsorption system (Item II.A.27).

II.A.27 Activated Carbon Adsorption System
One (1) activated carbon adsorption system controls the ashing furnace (Item II.A.26).

SECTION II: SPECIAL PROVISIONS

II.B REQUIREMENTS AND LIMITATIONS

II.B.1 Site-Wide Requirements
II.B.1.a The owner/operator shall not allow visible emissions from the following emission points to
exceed the following values:

A. All fabric filter baghouse exhaust stacks - 10%.

B. All electrostatic precipitator exhaust stacks - 10% .

C. All scrubber exhaust stacks - 10%.

D. All incinerator exhaust stacks - 10%.

E. All boiler exhaust stacks - 10%.

F. All other points - 20%.

[R307-401-8]

II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-401-8]

DAQE-AN103670030-24
Page 8

II.B.1.b The owner/operator shall not produce more than the following:

A. 12,000,000 troy ounces of gold per rolling 12-month period.

B. 60,000,000 troy ounces of silver per rolling 12-month period.

C. 400 tons of sweeps per rolling 12-month period.

[R307-401-8]

II.B.1.b.1 The owner/operator shall:

A. Determine gold, silver, and sweeps production by company production records.

B. Record gold and silver production on a daily basis and record sweeps production.
on a monthly basis

C. Use the gold and silver production data to calculate a new rolling 12-month total by
the 20th day of each month using data from the previous 12 months.

D. Use the sweeps production data to calculate a new rolling 12-month total by the
20th day of January, April, July, and October of each year using data from the
previous 12 months.

E. Keep the gold, silver, and sweeps production records for all periods the plant is in
operation.

[R307-401-8]

II.B.2 Baghouse Requirements
II.B.2.a The owner/operator shall use baghouses to control particulate emissions from the sweeps
preparation process, melt room furnaces, electric tilt furnaces, electric push-out furnaces, and the
ashing furnace. [R307-401-8]

II.B.2.b The owner/operator shall install a manometer or magnehelic pressure gauge to measure the static
pressure differential across each baghouse. [R307-401-8]

II.B.2.b.1 The pressure gauge shall be located such that an inspector/operator can safely read the indicator
at any time. [R307-401-8]

II.B.2.b.2 The pressure gauge shall measure the static pressure differential in 1-inch water column
increments or less. [R307-401-8]

II.B.2.c During operation of each baghouse, the owner/operator shall maintain the static pressure
differential within the range recommended by the manufacturer for normal operations.
[R307-401-8]

II.B.2.c.1 The owner/operator shall record the static pressure differential at least once per operating day
while each baghouse is operating. [R307-401-8]

DAQE-AN103670030-24
Page 9

II.B.2.c.2 The owner/operator shall maintain the following records of the static pressure differential:

A. Unit identification;

B. Manufacturer recommended static pressure differential range for the unit;

C. Daily static pressure differential readings;

D. Date of reading.

[R307-401-8]

II.B.2.d At least once every 12 months, the owner/operator shall calibrate each pressure gauge in
accordance with the manufacturer's instructions or replace the pressure gauge. [R307-401-8]

II.B.2.d.1 The owner/operator shall maintain records of each pressure gauge calibrations and replacements.
[R307-401-8]

II.B.3 Emergency Engine Requirements
II.B.3.a The owner/operator shall not operate the 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 engine during emergencies. [40 CFR 63 Subpart ZZZZ, 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 the 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.

[40 CFR 63 Subpart ZZZZ, R307-401-8]

II.B.3.b The owner/operator shall only use natural gas as fuel in the emergency engine. [R307-401-8]

DAQE-AN103670030-24
Page 10

II.B.4 Wet Scrubber Requirements
II.B.4.a The owner/operator shall use the following scrubbers to control the following process streams:

Scrubber Process Stream
Scrubber #248 silver anode slime washing process, silver nitrate plant, and slime
plant.

Scrubber #359 gold electrolytic cells, gold refinery wet circuits, gold chloride
electrolytic production, silver chlorides sludge processing,
chlorination furnaces, melt furnaces, tilt furnaces, push-out
furnaces, and drying cabinets.

Scrubber #760 wastewater treatment tanks and laboratory.

Scrubber #761 silver electrolytic cells.

All exhaust air from the above-mentioned process streams shall be routed through the indicated
scrubber before being vented to the atmosphere.

[R307-401-8]

II.B.4.b During operation of each scrubber, the owner/operator shall maintain both the pressure drop and
the liquid flow rate within the respective range recommended by the manufacturer for normal
operations. [R307-401-8]

II.B.4.b.1 The parameters shall be monitored with instruments located such that an inspector/operator can
safely read the output any time. [R307-401-8]

II.B.4.c The owner/operator shall record both the pressure drop and liquid flow rate at least once per
operating day while each scrubber is operating. [R307-401-8]

II.B.4.c.1 The owner/operator shall maintain the following records of the pressure drop and liquid flow
rate:

A. Unit identification;

B. Manufacturer-recommended pressure drop and liquid flow rate range;

C. Daily pressure drop and liquid flow rate readings;

D. Date of reading.

[R307-401-8]

II.B.4.d At least once every 12 months, the owner/operator shall calibrate each instrument in accordance
with the manufacturer's instructions or replace the instrument. [R307-401-8]

II.B.4.d.1 The owner/operator shall maintain records of each instrument calibrations and replacements.
[R307-401-8]

II.B.4.e The owner/operator shall install a scrubber (ID# 761) that is certified to meet a NOx emission
reduction of no less than 24%. [R307-401-8]

II.B.4.e.1 To demonstrate compliance with the above condition, the owner/operator shall maintain records
of the manufacturer's emissions guarantee for the installed scrubber. [R307-401-8]

DAQE-AN103670030-24
Page 11

PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents:

Supersedes AO DAQE-AN103670029-24 dated April 4, 2024
Is Derived From NOI dated May 28, 2024

DAQE-AN103670030-24
Page 12

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-

RN103670030
June 11, 2024

Stewart Hogan
Asahi Refining USA, Inc.
4601 West 2100 South
West Valley City, UT 84120
[e-mail]

Dear Stewart Hogan,

Re: Engineer Review - Administrative Amendment:
Administrative Amendment to Approval Order DAQE-AN103670029-24 to Replace a Melt
Furnace under R307-401-12
Project Number: N103670030

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 (NSR) permitting program. Asahi
Refining USA, Inc. should complete this review within 10 business days of receipt.

Asahi Refining USA, Inc. should contact Christine Bodell at [phone] if there are questions or
concerns with the review of the draft permit conditions. Upon resolution of your concerns, please email
Christine Bodell at [e-mail] the signed cover letter. Upon receipt of the signed cover letter,
the DAQ will prepare an Approval Order (AO) for signature by the DAQ Director.

If Asahi Refining USA, Inc. does not respond to this letter within 10 business days, the project will move
forward without source concurrence. If Asahi Refining USA, Inc. 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

Engineer Review N103670030: Asahi Refining Inc.
June 11, 2024
Page 1
UTAH DIVISION OF AIR QUALITY
ENGINEER REVIEW

SOURCE INFORMATION

Project Number N103670030
Owner Name Asahi Refining USA, Inc.
Mailing Address 4601 West 2100 South
West Valley City, UT, 84120

Source Name Asahi Refining USA, Inc.- Precious Metals Refinery
Source Location 4601 West 2100 South
West Valley City, UT 84120

UTM Projection 415,495 m Easting, 4,508,700 m Northing
UTM Datum NAD83
UTM Zone UTM Zone 12
SIC Code 3339 (Primary Smelting & Refining of Nonferrous Metals,
Except Copper & Aluminum)

Source Contact Stewart Hogan
Phone Number [phone]
Email [e-mail]

Billing Contact Stewart Hogan
Phone Number 801-924-6089
Email [e-mail]

Project Engineer Christine Bodell, Engineer
Phone Number [phone]
Email [e-mail]

Notice of Intent (NOI) Submitted May 28, 2024
Date of Accepted Application May 31, 2024

Engineer Review N103670030: Asahi Refining Inc.
June 11, 2024
Page 2
SOURCE DESCRIPTION

General Description
Asahi Refining USA, Inc. (Asahi) currently operates a precious metals refinery in West Valley
City, Salt Lake County. Mined doré and scrap are melted and tested for purity using small
electric induction furnaces and then separated depending on gold and silver content. Separation is
achieved by using various inorganic chemicals and electrolytic methods. Silver is poured into
anode molds and then placed into the electrolytic cells. The cells contain silver nitrate solution,
and the low voltage current causes silver crystal to form onto a cathode plate. The silver crystal is
scraped off and collected.

NSR Classification:
Administrative Amendment

Source Classification
Located in Northern Wasatch Front O3 NAA, Salt Lake City UT PM2.5 NAA, Salt Lake County
SO2 NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
MACT (Part 63), A: General Provisions
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines

Project Proposal
Administrative Amendment to Approval Order DAQE-AN103670029-24 to Replace a Melt
Furnace under R307-401-12

Project Description
Asahi Refining Inc. (Asahi) is currently permitted to operate three (3) natural gas-fueled melt
furnaces, each rated less than 5 MMBtu/hr (see Approval Order DAQE-AN103670029-24,
Equipment ID II.A.14). Asahi will be replacing one (1) melt furnace with one (1) electric tilt
furnaces. The new and existing electric tilt furnaces (see Approval Order DAQE-AN103670029-
24, Equipment ID II.A.15) use the same control technologies as the melt furnaces: a nanofilter
baghouse made by UAS or the combination of the venturi scrubber, WESP II, and scrubber #359.

Asahi is not requesting to increase any production and/or operational limits. No emissions are
increasing. This project meets the requirements of UAC R307-401-12 Reduction in Air Pollutants
and does not require a public comment period.

EMISSION IMPACT ANALYSIS
This is an administrative amendment under R307-401-12. No emissions are increasing at this time. Therefore,
modeling is not required. [Last updated May 31, 2024]

Engineer Review N103670030: Asahi Refining Inc.
June 11, 2024
Page 3
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 0.06
CO2 Equivalent 0 994.70
Carbon Monoxide 0 0.73
Lead 0 0.01
Nitrogen Oxides 0 4.31
Particulate Matter - PM10 0 2.01
Particulate Matter - PM2.5 0 2.01
Sulfur Dioxide 0 6.11
Volatile Organic Compounds 0 0.09

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Chlorine (CAS #7782505) 0 800
Hexane (CAS #110543) 0 20
Hydrochloric Acid (Hydrogen Chloride) (CAS #7647010) 0 1600
Lead (CAS #7439921) 0 20
Selenium & Compounds (CAS #253) 0 60
Change (TPY) Total (TPY)
Total HAPs 0 1.25

Note: Change in emissions indicates the difference between previous AO and proposed modification.

Engineer Review N103670030: Asahi Refining Inc.
June 11, 2024
Page 4
Review of BACT for New/Modified Emission Units

1. BACT review regarding New Electric Tilt Furnace
This is an administrative amendment under R307-401-12. No emissions are increasing at this time.
Therefore, a BACT analysis is not required. [Last updated May 31, 2024]

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]

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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):

II.A THE APPROVED EQUIPMENT

II.A.1 Metal Refinery
Precious Metals Refinery Plant

II.A.2 Wastewater Treatment
Wastewater effluent treatment. Process controlled by scrubber #760

II.A.3 Electrolytic Cells
Silver electrolytic cell (refining of silver). Process controlled by scrubber #761.

II.A.4 Electrolytic Cells
Gold electrolytic cell (refining of gold). Process controlled by scrubber #359.

II.A.5 Wet Circuit
Gold refinery wet circuits (part of the gold refining process). Process controlled by scrubber
#359.

II.A.6 Chlorination
Gold chloride electrolytic production (refining of gold). Process controlled by scrubber #359.

II.A.7 Slime Washing
Silver anode slime washing process (recovery of gold). Process controlled by scrubber #248.

II.A.8 Wet Chlorides Treatment
Hydrometallurgical process for silver chlorides sludge processing (recovery of gold).
Controlled by scrubber #359.

II.A.9 Fabric-Filter Baghouse
Four (4) fabric-filter baghouses

One baghouse controls emissions from the sweeps preparation process. Two baghouses
control emissions from the melt room furnaces, the electric tilt furnaces, and the electric push-
out furnaces. One baghouse controls the ashing furnace (Item II.A.26).

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II.A.10 Boiler
One (1) boiler, natural gas-fueled, rated less than 5 MMBtu/hr

II.A.11 Dust Collector
Dust collector for welding fume and grinding dust control in maintenance shop

II.A.12 Electrostatic Precipitator
One (1) wet-electrostatic precipitator (ID: WESP II)

II.A.13 Chlorination Furnaces
Four (4) electric-induction chlorination furnaces. Process controlled by venturi scrubber,
WESP II, and scrubber #359.

II.A.14 Melt Furnaces
Two (2) melt-room furnaces, natural gas-fueled, rated less than 5 MMBtu/hr each. Process
controlled by a nanofilter baghouse made by UAS or the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.15 Tilt Furnaces (One New)
Eight (8) electric-tilt furnaces. Process controlled by a nanofilter baghouse made by UAS or
the combination of the venturi scrubber, WESP II, and scrubber #359.

II.A.16 Push-out Furnaces
Four (4) electric push-out furnaces. Process controlled by baghouse or the combination of the
venturi scrubber, WESP II, and scrubber #359.

II.A.17 Emergency Generator Engine
One (1) emergency power generator engine, natural gas-fueled, rated at 60 kW

II.A.18 Combustion Afterburner
One (1) incinerator, natural gas-fueled, rated less than 5 MMBtu/hr

II.A.19 Nitrate Plant
Silver nitrate plant (recovery of silver). Process controlled by scrubber #248.

II.A.20 Slime Plant
Slime plant (recovery of gold). Process controlled by scrubber #248.

II.A.21 Drying Cabinets
Five (5) electric drying cabinets. Process controlled by the combination of the venturi
scrubber, WESP II, and scrubber #359.

II.A.22 Drying Cabinet
One (1) drying cabinet, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.23 Wet Scrubbers
Four (4) packed bed wet scrubbers (ID: 760, 359, 248, 761)

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II.A.24 Venturi Scrubber
One (1) venturi scrubber attached to WESP II as a pre-scrubber.

II.A.25 Tank System
Silver reduction tanks (recovery of silver). Process controlled by scrubber #248.

II.A.26 Ashing Furnace
One (1) dental scrap ashing furnace. Process controlled by baghouse (Item II.A.9) and
activated carbon adsorption system (Item II.A.27).

II.A.27 Activated Carbon Adsorption System
One (1) activated carbon adsorption system controls the ashing furnace (Item II.A.26)

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 Site-Wide Requirements
II.B.1.a The owner/operator shall not allow visible emissions from the following emission points to
exceed the following values:

A. All fabric filter baghouse exhaust stacks - 10%

B. All electrostatic precipitator exhaust stacks - 10%

C. All scrubber exhaust stacks - 10%

D. All incinerator exhaust stacks - 10%

E. All boiler exhaust stacks - 10%

F. All other points - 20%

[R307-401-8]

II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-401-8]

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II.B.1.b The owner/operator shall not produce more than the following:

A. 12,000,000 troy ounces of gold per rolling 12-month period

B. 60,000,000 troy ounces of silver per rolling 12-month period

C. 400 tons of sweeps per rolling 12-month period

[R307-401-8]

II.B.1.b.1 The owner/operator shall:

A. Determine gold, silver, and sweeps production by company production records

B. Record gold and silver production on a daily basis and record sweeps production
on a monthly basis

C. Use the gold and silver production data to calculate a new rolling 12-month total by
the 20th day of each month using data from the previous 12 months

D. Use the sweeps production data to calculate a new rolling 12-month total by the
20th day of January, April, July and October of each year using data from the
previous 12 months.

E. Keep the gold, silver, and sweeps production records for all periods the plant is in
operation.

[R307-401-8]

II.B.2 Baghouse Requirements
II.B.2.a The owner/operator shall use baghouses to control particulate emissions from the sweeps
preparation process, melt room furnaces, electric tilt furnaces, electric push-out furnaces, and
the ashing furnace. [R307-401-8]

II.B.2.b The owner/operator shall install a manometer or magnehelic pressure gauge to measure the
static pressure differential across each baghouse. [R307-401-8]

II.B.2.b.1 The pressure gauge shall be located such that an inspector/operator can safely read the
indicator at any time. [R307-401-8]

II.B.2.b.2 The pressure gauge shall measure the static pressure differential in 1-inch water column
increments or less. [R307-401-8]

II.B.2.c During operation of each baghouse, the owner/operator shall maintain the static pressure
differential within the range recommended by the manufacturer for normal operations. [R307-
401-8]

II.B.2.c.1 The owner/operator shall record the static pressure differential at least once per operating day
while each baghouse is operating. [R307-401-8]

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II.B.2.c.2 The owner/operator shall maintain the following records of the static pressure differential:

A. Unit identification;

B. Manufacturer recommended static pressure differential range for the unit;

C. Daily static pressure differential readings;

D. Date of reading.

[R307-401-8]

II.B.2.d At least once every 12 months, the owner/operator shall calibrate each pressure gauge in
accordance with the manufacturer's instructions or replace the pressure gauge. [R307-401-8]

II.B.2.d.1 The owner/operator shall maintain records of each pressure gauge calibrations and
replacements. [R307-401-8]

II.B.3 Emergency Engine Requirements
II.B.3.a The owner/operator shall not operate the 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 engine during emergencies. [40 CFR 63 Subpart ZZZZ, 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 the 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

[40 CFR 63 Subpart ZZZZ, R307-401-8]

II.B.3.b The owner/operator shall only use natural gas as fuel in the emergency engine. [R307-401-8]

II.B.4 Wet Scrubber Requirements

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II.B.4.a The owner/operator shall use the following scrubbers to control the following process streams.
Scrubber Process Stream
Scrubber #248 silver anode slime washing process, silver nitrate plant, and slime
plant

Scrubber #359 gold electrolytic cells, gold refinery wet circuits, gold chloride
electrolytic production, silver chlorides sludge processing,
chlorination furnaces, melt furnaces, tilt furnaces, push-out
furnaces, and drying cabinets

Scrubber #760 wastewater treatment tanks and laboratory

Scrubber #761 silver electrolytic cells

All exhaust air from the above-mentioned process streams shall be routed through the
indicated scrubber before being vented to the atmosphere.

[R307-401-8]

II.B.4.b During operation of each scrubber, the owner/operator shall maintain both the pressure drop
and the liquid flow rate within the respective range recommended by the manufacturer for
normal operations. [R307-401-8]

II.B.4.b.1 The parameters shall be monitored with instruments located such that an inspector/operator
can safely read the output any time. [R307-401-8]

II.B.4.c The owner/operator shall record both the pressure drop and liquid flow rate at least once per
operating day while each scrubber is operating. [R307-401-8]

II.B.4.c.1 The owner/operator shall maintain the following records of the pressure drop and liquid flow
rate:

A. Unit identification;

B. Manufacturer recommended pressure drop and liquid flow rate range;

C. Daily pressure drop and liquid flow rate readings;

D. Date of reading.

[R307-401-8]

II.B.4.d At least once every 12 months, the owner/operator shall calibrate each instrument in
accordance with the manufacturer's instructions or replace the instrument. [R307-401-8]

II.B.4.d.1 The owner/operator shall maintain records of each instrument calibrations and replacements.
[R307-401-8]

II.B.4.e The owner/operator shall install a scrubber (ID# 761) that is certified to meet a NOx emission
reduction of no less than 24%. [R307-401-8]

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II.B.4.e.1 To demonstrate compliance with the above condition, the owner/operator shall maintain
records of the manufacturer's emissions guarantee for the installed scrubber. [R307-401-8]

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PERMIT HISTORY

When issued, the approval order shall supersede (if a modification) or will be based on the
following documents:

Supersedes AO DAQE-AN103670029-24 dated April 4, 2024
Is Derived From NOI dated May 28, 2024

REVIEWER COMMENTS

1. Comment regarding Reduction in Air Pollutant Applicability:
Asahi has requested to replace one (1) natural gas-fired melt furnaces, rated less than 5 MMBtu/hr,
with one (1) electric tilt furnace. All the natural gas-fired and electric tilt furnaces on site are
controlled by a nanofilter baghouse made by UAS or the combination of the venturi scrubber, WESP
II, and scrubber #359. The replacement results in a reduction of emissions from natural gas
combustion. The new equipment will operate under existing emissions limitations. Therefore, this
project meets the requirements of Utah Administrative Code R307-401-12, Reduction in Air
Pollutants.

Asahi has elected to make no adjustments the current Potential to Emit (PTE). Therefore, the
Summary of Emissions table will not reflect any changes. [Last updated May 31, 2024]

2. Comment regarding NSPS and MACT Applicability:
40 CFR 63 Subpart ZZZZ - National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines
The provisions of this subpart are applicable to owners/operators of stationary RICE at a major or
area sources of HAP emissions. The facility includes (1) 60 kW, natural gas-fired emergency
stationary engine. The provisions of MACT Subpart ZZZZ apply as the stationary reciprocating
internal combustion engine (RICE) is at an area source of HAP emissions. The engine is not
designated as nonroad and are not exempt are affected sources under this regulation. Therefore,
MACT Subpart ZZZZ applies to this facility.

The engine was installed prior to June 12, 2006. Therefore, 40 CFR 60 Subpart JJJJ (Standards of
Performance for Stationary Spark Ignition Internal Combustion Engines) does not apply.
[Last updated May 31, 2024]

3. Comment regarding Title V Applicability:
Title V of the 1990 CAA (Title V) applies to the following:

A. Any major source

B. Any source subject to a standard, limitation, or other requirement under Section 111 of the
Act, Standards of Performance for New Stationary Sources

C. Any source subject to a standard or other requirement under Section 112 of the Act,
Hazardous Air Pollutants

D. Any Title IV-affected source

This facility is not a major source and is not a Title IV source, but is subject to 40 CFR 63 MACT

Engineer Review N103670030: Asahi Refining Inc.
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Page 13
Subparts A and ZZZZ regulations. However, Title V does not apply because MACT Subpart ZZZZ
exempts sources from the obligation to obtain a permit under 40 CFR part 70 (Title V permit) if the
source is not otherwise required by law to obtain a permit. There are no other reasons why this
source would be required to obtain a part 70 permit; therefore, Title V does not apply to this facility.
[Last updated May 31, 2024]

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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