DAQ-2024-010426

Kennecott Utah Copper, LLC
Kennecott Tailings & Water Services
4700 Daybreak Parkway South Jordan, Utah 84009
USA
T 801-204-3051
F 801-569-7217
Paula Doughty
Manager, Hydro, Tailings and Water Services
Mr. Bryce Bird, Director Department of Environmental Quality Division of Air Quality P.O. Box 144820 Salt Lake City, Utah 84114-4820

July 30th, 2024

Subject: Approval Order (AO) DAQE-AN0572018-06
Kennecott Tailings Quarterly Report Second Quarter 2024
Dear Mr. Bird: In compliance with Kennecott Utah Copper (KUC) Approval Order (AO) DAQE-AN0572018-06, dated April 6, 2006, attached is the Tailings Quarterly
Report for the Second quarter of 2024.

• All monitoring and record-keeping requirements were met during the
reporting period.
• 0 acres were seeded during the reporting period.
• Polymer or chemical dust suppressant was applied to a total of 521
acres during the reporting period; See Control Measures table for
suppressant and polymer application acres.
• The 95% minimum wetness criterion was met as determined during
grid inspections conducted during the Second quarter of 2024. Refer
to the attached surface wetness table.
• KUC continued to monitor weather conditions during the reporting period. Criteria for wind speeds were experienced on seven (7) days during the quarter. April 03, 2024 April 4, 2024 April 05, 2024 May 04, 2024 May 22, 2024 June 09, 2024 June 17, 2024
Based on information and beliefs formed after reasonable inquiry, the
statements and information in this document are true, accurate, and complete
(R307-415-5d). Should you have questions or need further information regarding this report, please feel free to contact me or Randall Naeve at 385-237-8949.
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5

Sincerely, Paula H. Doughty Manager, Hydro, Tailings and Water Services Attachments

Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5

KENNECOTT UTAH COPPER – TAILINGS QUARTERLY REPORT
2nd Quarter Report – 2024 This report reviews dust control activities for the reduction of fugitive dust at the Kennecott Utah Copper Tailings Site and fulfils reporting requirements as outlined in the Approval Order (AO) for this facility.
Control Measures
Area
Drill Seeding & Fertilizer (acres)
Hydro-seeding (acres)
Redrill (acres)
Total seeding (acres)
MCl, Pine Tar, Hy-Mulch, M-binder & Polymer Control (acres)
North 0 0 0 0 392 South 0 0 0 0 129 The acreage listed above is displayed on the attached maps as required in the
Approval Order (AO).
No acres on the site were treated with lime and biosolids to enhance vegetative growth.

Supplemental Dust Controls

In addition to the dust control methods outlined above, road watering was conducted as conditions warranted. Automatic high-pressure sprinklers were
also used on inactive construction cells in the north area. For second quarter 35 acres on the southeast corner of tailings property was capped.

Dike Interior Dust Control

The operational program of rotating tailings distribution from the peripheral
discharge system continued during the quarter in the north area. Tailings
distribution has been discontinued in the south area due to reclamation
activities.

Criteria For Wind Reporting

During the second quarter of 2024, KUC continued to monitor meteorological
conditions. There were seven (7) days during the period when the criteria for
wind reporting was met. The Approval Order (AO) combines the north
expansion with the south area and defines criteria for winds greater than 25
mph for greater than one hour from any direction during which no
precipitation occurred.
The analyses of tailings impoundment surface wetness for the second quarter
of 2024 are detailed in the following table:

Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5

WETNESS CATEGORY (%)

Date
Deep
Water
Shallow
Water

Saturated
Wet,
Unsaturated
Treated/
Crusted
All
Dry
2024.04.23 36% 24% 38% 0% 0% 0%
2024.05.15
2024.06.18
31%
31%
27%
32%
37%
24%
4%
10%
0%
0%
0%
3%

The observed tailings pond surface dryness is below the maximum allowable
surface dryness of 5%.

Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:April 3, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 6.2 127.1
01 - 02:00 3.3 146.3
02 - 03:00 4.6 146.6
03 - 04:00 8.8 131.5
04 - 05:00 10.7 119.6
05 - 06:00 3.3 318.6
06 - 07:00 4.3 79.3
07 - 08:00 3.4 138.8
08 - 09:00 3.8 126.5
09 - 10:00 3.1 242.0
10 - 11:00 5.0 275.2
11 - 12:00 6.0 313.5
12 - 13:00 5.8 315.1
13 - 14:00 5.6 299.5
14 - 15:00 6.7 308.5
15 - 16:00 6.7 317.7
16 - 17:00 5.4 343.6
17 - 18:00 9.9 104.3
18 - 19:00 25.3 138.6
19 - 20:00 25.1 154.7
20 - 21:00 9.2 154.2
21 - 22:00 8.2 149.9
22 - 23:00 13.0 150.9
23 - 24:00 15.0 149.9
Hrs ≥ 25 mph:2
Daily Avg:8.3
Max Wind &
Corresponding
Direction:
25.3 138.6
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:April 4, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 15.7 170.4
01 - 02:00 11.5 145.4
02 - 03:00 11.5 151.3
03 - 04:00 16.9 160.1
04 - 05:00 17.8 149.7
05 - 06:00 23.6 167.2
06 - 07:00 20.3 161.7
07 - 08:00 15.2 133.2
08 - 09:00 16.0 135.5
09 - 10:00 17.0 163.8
10 - 11:00 17.4 157.5
11 - 12:00 22.5 168.2
12 - 13:00 24.7 162.2
13 - 14:00 26.2 152.6
14 - 15:00 24.0 167.3
15 - 16:00 20.4 182.0
16 - 17:00 28.9 176.0
17 - 18:00 25.3 174.4
18 - 19:00 25.3 189.2
19 - 20:00 25.1 201.4
20 - 21:00 18.0 212.0
21 - 22:00 18.9 211.1
22 - 23:00 15.3 190.3
23 - 24:00 16.6 178.7
Hrs ≥ 25 mph:5
Daily Avg:19.8
Max Wind &
Corresponding
Direction:
28.9 176.0
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:April 5, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 15.5 148.1
01 - 02:00 12.8 133.2
02 - 03:00 15.0 148.8
03 - 04:00 14.8 159.8
04 - 05:00 12.6 148.8
05 - 06:00 13.0 152.9
06 - 07:00 10.5 153.6
07 - 08:00 11.9 158.8
08 - 09:00 17.9 165.2
09 - 10:00 24.6 175.5
10 - 11:00 21.2 188.3
11 - 12:00 22.8 227.5
12 - 13:00 23.2 200.5
13 - 14:00 25.4 198.4
14 - 15:00 16.7 114.2
15 - 16:00 11.7 155.6
16 - 17:00 23.0 307.7
17 - 18:00 13.3 343.7
18 - 19:00 8.7 3.4
19 - 20:00 7.1 99.8
20 - 21:00 6.8 155.5
21 - 22:00 5.3 176.7
22 - 23:00 3.3 211.2
23 - 24:00 8.4 268.8
Hrs ≥ 25 mph:1
Daily Avg:14.4
Max Wind &
Corresponding
Direction:
25.4 198.4
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:May 4, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 5.2 148.5
01 - 02:00 1.3 165.1
02 - 03:00 6.3 138.2
03 - 04:00 8.8 138.3
04 - 05:00 10.3 123.6
05 - 06:00 10.6 147.6
06 - 07:00 10.1 142.9
07 - 08:00 12.4 123.2
08 - 09:00 16.8 118.8
09 - 10:00 11.5 150.7
10 - 11:00 9.2 252.3
11 - 12:00 6.8 301.0
12 - 13:00 19.6 155.1
13 - 14:00 23.5 142.4
14 - 15:00 18.7 146.8
15 - 16:00 19.4 144.7
16 - 17:00 18.5 156.2
17 - 18:00 16.6 166.5
18 - 19:00 12.2 162.6
19 - 20:00 10.7 168.0
20 - 21:00 12.9 165.3
21 - 22:00 13.5 169.1
22 - 23:00 13.9 168.5
23 - 24:00 29.0 188.5
Hrs ≥ 25 mph:1
Daily Avg:13.2
Max Wind &
Corresponding
Direction:
29.0 188.5
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:May 22, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 10.6 120.4
01 - 02:00 5.8 170.9
02 - 03:00 10.8 149.8
03 - 04:00 9.9 163.7
04 - 05:00 14.9 156.5
05 - 06:00 13.2 158.0
06 - 07:00 15.9 154.2
07 - 08:00 13.1 157.6
08 - 09:00 8.4 180.6
09 - 10:00 11.7 158.1
10 - 11:00 12.6 157.6
11 - 12:00 8.0 171.3
12 - 13:00 6.5 269.4
13 - 14:00 10.8 267.6
14 - 15:00 10.0 265.9
15 - 16:00 8.1 267.1
16 - 17:00 7.3 266.8
17 - 18:00 6.7 294.7
18 - 19:00 25.3 262.1
19 - 20:00 25.1 324.7
20 - 21:00 4.4 307.7
21 - 22:00 12.0 264.9
22 - 23:00 26.5 337.0
23 - 24:00 23.0 334.7
Hrs ≥ 25 mph:3
Daily Avg:12.5
Max Wind &
Corresponding
Direction:
26.5 337.0
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:June 9, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 8.0 134.9
01 - 02:00 5.0 167.1
02 - 03:00 5.3 284.6
03 - 04:00 4.2 316.9
04 - 05:00 4.7 201.3
05 - 06:00 7.1 319.4
06 - 07:00 11.6 138.4
07 - 08:00 8.5 142.6
08 - 09:00 8.7 122.3
09 - 10:00 9.7 111.3
10 - 11:00 7.1 67.7
11 - 12:00 8.4 73.0
12 - 13:00 11.6 120.2
13 - 14:00 10.5 115.0
14 - 15:00 10.6 127.8
15 - 16:00 10.6 168.8
16 - 17:00 8.4 158.6
17 - 18:00 11.7 153.6
18 - 19:00 25.3 166.6
19 - 20:00 25.1 163.8
20 - 21:00 19.3 171.9
21 - 22:00 17.3 208.8
22 - 23:00 17.1 319.6
23 - 24:00 8.3 298.5
Hrs ≥ 25 mph:2
Daily Avg:11.0
Max Wind &
Corresponding
Direction:
25.3 166.6
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Date:June 17, 2024
Wind Speed Wind Direction
MST Hour mph (1 hr avg)deg (1 hr unit vector)
00 - 01:00 3.8 271.0
01 - 02:00 5.9 169.8
02 - 03:00 3.5 100.3
03 - 04:00 4.2 176.7
04 - 05:00 5.9 131.5
05 - 06:00 6.8 124.6
06 - 07:00 6.9 128.1
07 - 08:00 2.7 162.5
08 - 09:00 6.9 305.6
09 - 10:00 20.6 307.2
10 - 11:00 21.0 311.0
11 - 12:00 18.5 316.8
12 - 13:00 18.7 318.5
13 - 14:00 19.6 317.0
14 - 15:00 22.1 319.8
15 - 16:00 30.7 314.3
16 - 17:00 29.1 316.3
17 - 18:00 22.6 320.1
18 - 19:00 25.3 324.1
19 - 20:00 25.1 359.8
20 - 21:00 13.1 15.8
21 - 22:00 6.8 29.6
22 - 23:00 4.9 5.6
23 - 24:00 6.4 0.5
Hrs ≥ 25 mph:4
Daily Avg:13.8
Max Wind &
Corresponding
Direction:
30.7 314.3
Center Tailings
Kennecott Utah Copper
Daily Wind Report Based on Hour Averages
Tailings Impoundment Station
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Kennecott North TailingsSurvey Department
NORTH
AMENDMENTS NTS
2024 SOILS 0
Second QTR. MAG-CHLORIDE 2024
STEVE HUNTER
2024 PROJECTS
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Kennecott North TailingsSurvey Department
NORTH
AMENDMENTS NTS
2024 SOILS 0
Second QTR. POLYMER 2024
STEVE HUNTER
2024 PROJECTS
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5
Docusign Envelope ID: 94A3714D-C92C-4CD8-9583-663F518044A5