5/7/26
In the matter of PETITION FOR MODIFICATION
Kennecott Utah Copper LLC
Kennecott Keystone Underground
Mine I.D. No. 42-01392 Docket No. M-2025-004-M
PROPOSED DECISION AND ORDER
On August 29, 2025, Kennecott Utah Copper LLC filed a petition seeking modification of the application of 30 Code of Federal Regulations (30 C.F.R.) § 57. 11052(d) at its Kennecott Keystone Underground mine located in Salt Lake County, Utah. The petitioner alleges that the alternative method in the petition will at all times guarantee no less than the same measure of protection afforded to the miners by the standard.
The petitioned standard, 30 C.F.R § 57.11052(d) states, in relevant part,
Refuge areas shall be – provided with compressed air lines, waterlines, suitable handtools, and stopping materials.
The petitioner is requesting a modification of the standard to allow the use of sealed bottled water in leu of waterlines for supplying potable water. Non-potable water lines will still be provided outside of each refuse chamber for firefighting, dust control, and equipment cooling purposes.
MSHA personnel investigated the merits of the petition and filed a report of their findings with the Administrator for Mine Safety and Health Enforcement. After a careful review of the entire record, including the petition and MSHA's investigative report, the Administrator issues this Proposed Decision and Order.
Findings of Fact and Conclusions of Law
MSHA investigated pertinent details of the Kennecott Keystone Underground mine on February 2 and 3, 2026. The investigation included an item-by-item review of the proposed petition and an onsite mine visit. During the onsite visit, the MSHA investigator verified that the proposed Petition for Modification (PFM) was posted on the mine’s bulletin board and explained the PFM process and all stipulations to the miners and supervisors.
The following individuals participated in the investigation at the mine as representatives of Kennecott Utah Copper LLC:
Shane Sandback, Senior Safety Advisor
Tula Khuyag, Ventilation Engineer
This is a nonunion mine and there was no Representative of Miners identified; however, MSHA interviewed five miners regarding the PFM. No negative comments were provided by any of the miners interviewed during the investigation.
The granting of this petition would affect all underground miners at this mine.
The petitioner states that the Kennecott Keystone Underground mine has never installed a potable water line to its refuge chambers. The underground portal is located at the bottom of the open pit mine site, making installation of a dedicated potable water line infrastructure impractical due to elevation, routing constraints, and logistical feasibility. Since underground development began in 2012, the water lines connected to the refuge chambers have been non-potable service water lines. These lines were never designed or intended to deliver drinking-quality water to miners.
The petitioner further stated that prior to approximately 2021, they were unaware that a Petition for Modification could be submitted to address the potable water requirement under 30 CFR §57.11052. A Petition for Modification was brought to the operator’s attention by the MSHA Field Office Supervisor in Salt Lake City. Following that guidance, the operator began evaluating the feasibility of formally requesting a modification. According to the petitioner, the current petition reflects a formal effort to resolve a long-standing infrastructure limitation through an alternative method that ensures sanitary, sealed potable water is available inside each refuge chamber.
During the onsite inspection, MSHA performed a physical inspection of all in-service refuge chambers and life-support systems. This included inspecting 18 refuge chambers, all manufactured by MineARC.
MSHA inspected and verified the following information for each in-service refuge chamber:
• Structural integrity and door seals (multi-point latches and gaskets).
• Presence and operation of gas monitoring instrumentation (O2, CO, CO2).
• Operation of CO2 scrubbing systems.
• Compressed air connection and fittings.
• Presence of bottled medical-grade oxygen cylinders and oxygen candles in chambers rated for 12+ persons.
• Emergency lighting and battery backup.
• Radio and telephone communications.
• Air conditioning/ temperature control systems, where installed.
• Sanitation facilities and toilet supplies.
• Packaged potable water (sealed bottles), blankets, food rations, and first aid supplies.
• Documentation of inspections, tests, and OEM service.
• Chambers were verified to be ready for the rated occupancy for the manufacturer-rated 36-hour survivability period.
• Records inspected included inspection logs (3-week interval), OEM service records (4-month interval), water inventory logs, and SOPs for chamber relocation and maintenance
The 18 refuge chambers in service provided a total verified capacity for 172 miners.
The inspection examined and confirmed the structural nature of the chambers including heavy-gauge enclosure with reinforced frames; and sealed, outward opening doors with multi-point latches with gaskets. Doors offered clear egress paths with signage. Multi-gas monitors were installed in each chamber to continuously monitor oxygen, carbon dioxide, and carbon monoxide. Visual displays and audible alarms were provided to warn occupants if thresholds are reached.
Calibration and function checks were documented in inspection logs. Air Management & CO2 scrubbing systems were available to control CO2 accumulations. Compressed air interface for introducing breathable air was available. Compressed air is filtered and routed through filtration systems before distribution inside chamber. Bottled oxygen cylinders (medical grade) are present as backup oxygen supplies. Oxygen candles previously present in chambers designed for 12 persons or greater as a supplemental oxygen source have been replaced with an additional oxygen tank. This modification eliminates the presence of an open flame within the rescue chamber and reduces fire hazards.
Each refuge chamber was equipped with a full complement of life-support and safety systems designed to sustain occupants for both the manufacturer-rated 36-hour period and the 96-hour water recommendation of NIOSH.
On March 4, 2026, a follow up discussion was held between MSHA investigators and Shane Sandbak, senior safety advisor and representative of the mine operator, regarding the Petition for Modification at the Kennecott Keystone Underground mine. The original petition requested a 36-hour potable water supply in conjunction with relocating the existing water line. It was recommended that consideration be given to increasing the potable water supply to 96 hours to provide additional protection and increase the duration capability for miners in the event of an entrapment. Mr. Sandbak acknowledged and agreed with the recommendation and stated he will add additional potable water to increase the available supply from 36 hours to 96 hours. He placed a phone call during the discussion to begin arrangements for securing the additional water. Mr. Sandbak also stated that the existing water lines will remain connected and in service until the Petition for Modification is approved and a final order is received from MSHA. The water line will not be removed until approval is granted and the final order is in hand. Accordingly, the requested modification is being adjusted to stipulate 96 hours’ worth of bottled water shall be provided.
Non-potable waterlines remain present and are used for mine operations and firefighting. These lines are clearly marked as non-potable. Sealed packaged potable water will be stored inside each chamber. Each chamber has been provided with a minimum of 2.25 quarts of water per miner, per day (24-hour period). This is based on the recommendation of NIOSH. For 4 days (96-hour period), this requires 9 quarts, or 8.5 liters per person, packaged and labeled with expiration dates. Bottled water will be replaced as part of regular inspection/maintenance.
Conclusion
Based on the investigation discussed above, MSHA determined that sealed bottled potable water shall be an acceptable substitute for providing potable water in water lines if the operator follows all of the manufacturer’s recommendations and adheres to the Terms and Conditions of the Proposed Decision and Order.
On the basis of the petition and MSHA’s investigation findings, and the foregoing reasons, Kennecott Utah Copper LLC is granted a modification of the application of 30 C.F.R. § 57.11052(d) at its Kennecott Keystone Underground mine.
ORDER
Wherefore, pursuant to the authority delegated by the Secretary of Labor to the Administrator for Mine Safety and Health Enforcement and pursuant to Section 101(c) of the Federal Mine Safety and Health Act of 1977, 30 U.S.C. § 811(c), it is ordered that Kennecott Utah Copper LLC’s Petition for Modification of the application of 30 C.F.R. § 57.11052(d) in the Kennecott Keystone Underground mine is hereby:
GRANTED, conditioned upon compliance with the following requirements.
Terms and Conditions
1. This Order shall apply to the existing refuge chambers, to relocated refuge chambers, to future refuge chambers, and to all entrapment chambers intended to be used as refuge chambers.
2. Refuge chambers shall accommodate the maximum number of persons that can be expected to be working in each area of the mine at any time.
3. Each refuge chamber shall be supplied with water sufficient for the maximum designated occupancy, for at least 4 days (96 hours).
4. Potable Water Supply:
a. Drinking water shall be provided via commercially purchased purified water in individually portioned packaged pouches.
b. Sufficient water shall be provided in each refuge area to provide 2.25 quarts of water per person per day, for at least 4 days (96 hours).
c. Water shall be stored in a manner that makes the expiration dates readily visible for inspection.
d. Water shall be replaced according to the manufacturer’s specified expiration dates. If the expiration dates are not legible, or if they become illegible, the water shall be replaced by the end of the next working shift.
e. A supply of packaged disposable drinking cups (at least five cups per person) shall be maintained in the refuge chamber.
f. The condition and quantity of stored water shall be confirmed by inspection on at least a monthly basis, and the inspections shall be documented. This documentation shall be made available for review upon request by an Authorized Representative of the Secretary of Labor.
g. Written instructions for conservation of water shall be provided in the refuge chamber.
5. Life sustaining breathable air shall be provided to each refuge chamber using air via compressed air lines.
6. Tools and any repair materials for all refuge components (structure, air delivery system, door seals, etc.) including instructions shall be kept in each unit. This includes extra flow valves, wrenches, emergency sealing tape or adhesive patches, and duct tape.
7. Workplace Examinations performed in the area where the refuge chamber is located shall include a visual examination of the unit’s exterior for damage and tampering.
8. Training:
a. Applicable revisions or appropriate changes to the mine’s 30 C.F.R. Part 48 training plan regarding the conditions in this Order shall be submitted to the MSHA District Manager for revision and approval prior to the implementation of the training plan by the Petitioner.
b. Training on the proper use of the refuge chamber will be provided, at least once every six months, to those miners who might possibly transport or use them. Training must include all aspects of the use of the specific units employed at the mine, including the hazards associated with compressed oxygen cylinders, the carbon dioxide scrubbing process, the communications systems, and use of the gas detector(s) to monitor concentrations of carbon dioxide, carbon monoxide, oxygen, and other harmful gases specific to the mine.
9. The mine shall comply with all other requirements of 30 C.F.R. § 57.11052 – Refuge areas.
Unless specifically mentioned herein, nothing in this Order changes or supersedes the requirements otherwise imposed by the Mine Act, other mandatory standards or regulations, or approved plans.
The petitioner shall include the above terms and conditions in the initial and annual refresher training as required in its approved Part 48 training plans to ensure that miners are aware of the stipulations contained in this petition.
Any party to this action desiring a hearing on this matter must file in accordance with 30 C.F.R. § 44.14 within 30 days. The request for hearing must be filed with the Administrator for Mine Safety and Health Enforcement, 200 Constitution Ave NW, Suite C3522, Washington, DC, 20210.
Any hearing request must contain a concise summary of position on the issues of fact or law to be raised by the party requesting the hearing, including specific objections to the proposed decision. A party other than the Petitioner who has requested a hearing may also comment on all issues of fact or law presented in the petition, and any party to this action requesting a hearing may indicate a desired hearing site.
If no request for a hearing is filed within 30 days after service of this Proposed Decision and Order, the Decision and Order will become final and must be posted by the operator on the bulletin board at the mine.
Timothy R. Watkins
Administrator for
Mine Safety and Health Enforcement
Certificate of Service
I hereby certify that a copy of this proposed decision was served personally or mailed, postage paid, or provided by other electronic means this 7th day of May, 2026, to:
Shane Sandbak
Senior Safety Advisor
Kennecott Utah Copper LLC
4700 Daybreak Parkway
South Jordan, Utah 84009
shane.sandbak@riotinto.com
Derrick Tjernlund
Mine Safety and Health Specialist
cc: Mr. David Houghton, Director
Utah Office of Coal Mine Safety
940 S. Carbon Ave.
Price, UT 84501
dhoughton@utah.gov