DAQ-2025-002617

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. 800 346-3128
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

Department of
Environmental Quality

Tim Davis
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor
DAQC-506-25
Site ID 10346 (B5)

Matt Tobey, Manager, Smelter and Refinery
Rio Tinto Kennecott Utah Copper, LLC
4700 Daybreak Parkway
South Jordan, Utah 84009

Dear Mr. Tobey:

Re: Rio Tinto Kennecott (Rio Tinto) – Pretest Protocol for Nitrogen Oxides (NOx) and Sulfur
Dioxide (SO2) Relative Accuracy Test – Salt Lake County

The Utah Division of Air Quality (DAQ) reviewed Rio Tinto’s pretest protocol dated May 6,
2025. The proposed test shall be performed under the following conditions:

Rio Tinto’s monitoring system to be certified:
Point Source Channel Manufacturer Model # Monitor SN Low
Range
High
Range
Main Stack
(SME 011)
NOx Thermo Scientific 42iQLS 12128413438 0-100 0-10,000
SO2 Thermo Scientific 43iQ 12127413439 0-100 0-10,000
Flow Cemtek/KVB-Enertec Flow 100 0019 0-1” H2O
Acid Plant Tail
Gas (SME011b) SO2 Unisearch Associates FCSO2-B-P DAS22-011 0-150 0-1500

Alliance Technical Group will conduct a relative accuracy/performance specification test on Rio
Tinto’s continuous monitoring system.

Relative accuracy must be determined in the units of the emission standard or equivalent units of
the emission standard, i.e., tons/year shall be tested in pounds/hour.

The DAQ understands that testing will be conducted as follows:

Test Date Point Source Parameter EPA Reference Method
June 24, 2025 Main Stack NOx and SO2 Method 1, 2, 3A, 4, 6C, and 7E
June 25, 2025 Acid Plant Tail Gas SO2 Method 4, 6C
6 Û á Û Ù Û Þ
DAQC-506-25
Page 2

• Reference Method 1 - Sample and Velocity Traverses for Stationary Point Sources
as outlined in 40 CFR 60 Appendix A shall be used to determine the location and
number of sampling points as applicable.

• Reference Method 2 - Determination of Stack Gas Velocity and Volumetric Flow
Rate – (Type S Pitot Tube) as outlined in 40 CFR 60 Appendix A.

• Reference Method 3A - Determination of Oxygen and Carbon Dioxide
Concentrations in Emissions from Stationary Point Sources – (Instrumental
Analyzer Procedure) as outlined in 40 CFR 60 Appendix A.

• Reference Method 4 - Determination of Moisture Content in Stack Gases as
outlined in 40 CFR 60 Appendix A shall be used to determine the stack gas
moisture content.

• Reference Method 6C - Determination of Sulfur Dioxide Emissions from
Stationary Point Sources - (Instrumental Analyzer Procedure) as outlined in 40
CFR 60 Appendix A.

• Reference Method 7E - Determination of Nitrogen Oxide Emissions from
Stationary Point Sources - (Instrumental Analyzer Procedure) as outlined in 40
CFR 60 Appendix A.

• Deviations - The Director or the representative of the Director must be notified of
and approve deviations of the Reference Method test. Any deviation from these
conditions without approval from the DAQ may constitute rejection of these tests.

Acceptance of a protocol does not relieve the owner/operator and the testing
contractor from strict adherence to all applicable EPA methods, DAQ policies,
Utah Air Quality Rules (UAQR), and methods approved by the Director. Any
deviation from EPA methods, DAQ policies, UAQR, and methods approved by the
Director must be addressed separately and express written consent given prior to
commencement of testing.

• Field data (Point Source emission data and test data) shall be submitted to the DAQ
in a timely manner for review.

• The Director will determine the relative accuracy of each monitoring system based
on Point Source continuous emission monitoring data and test data acquired by the
staff member of the DAQ during the test.

• All test reports must be submitted to the Director not later than 60 days after
completion of the test.

DAQC-506-25
Page 3

• The test report shall include all raw calibration data, raw emission data with date,
time stamps.

Relative accuracy test reports must contain:

1. Point source continuous monitor, channel, manufacturer, and serial number,

2. Raw stack test data and continuous monitor data with date and time stamps.

3. Emission data reported in concentration (ppm or %) and units in the applicable
emission limit.

The DAQ requires that all test reports include a statement signed by a responsible official
certifying that:

1. Testing was conducted while the Point Source was operating at the rate and/or
conditions specified in the applicable approval order, operating permit, or federal
regulation.

2. During testing, the Point Source combusted fuels, used raw materials, and
maintained process conditions representative of normal operations, and operated
under such other relevant conditions specified by the Director.

3. Based on information and belief formed after reasonable inquiry, the statements
and information contained in the report are true, accurate, and complete.

Should you have any questions concerning this matter, contact me at [phone] or by email
at [e-mail].

Sincerely,

Rob Leishman, Environmental Scientist
Major Source Compliance Section

RL:rh

cc: Salt Lake County Health Department
Alliance Technical Group
* $ . # ( ) - — 4 A B v A ? A D @ ? w B ? ˜
Rob Leishman Jr