2024-28422. Petition for Modification of Application of Existing Mandatory Safety Standard

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Department of Labor

Mine Safety and Health Administration

AGENCY:

Mine Safety and Health Administration, Labor.

ACTION:

Notice.

SUMMARY:

This notice is a summary of a petition for modification submitted to the Mine Safety and Health Administration (MSHA) by South32 Hermosa Inc.

DATES:

All comments on the petition must be received by MSHA's Office of Standards, Regulations, and Variances on or before January 6, 2025.

ADDRESSES:

You may submit comments identified by Docket No. MSHA-2024-0088 by any of the following methods:

1. Federal eRulemaking Portal: https://www.regulations.gov. Follow the instructions for submitting comments for MSHA-2024-0088.

2. Fax: [phone].

3. Email: [e-mail].

4. Regular Mail or Hand Delivery: MSHA, Office of Standards, Regulations, and Variances, 201 12th Street South, 4th Floor West, Arlington, Virginia 22202-5452.

Attention: S. Aromie Noe, Director, Office of Standards, Regulations, and Variances. Persons delivering documents are required to check in at the receptionist's desk, 4th Floor West. Individuals may inspect copies of the petition and comments during normal business hours at the address listed above. Before visiting MSHA in person, call 202-693-9455 to make an appointment.

FOR FURTHER INFORMATION CONTACT:

S. Aromie Noe, Office of Standards, Regulations, and Variances at 202-693-9440 (voice), [e-mail] (email), or 202-693-9441 (fax). [These are not toll-free numbers.]

SUPPLEMENTARY INFORMATION:

Section 101(c) of the Federal Mine Safety and Health Act of 1977 and title 30 of the Code of Federal Regulations (CFR) part 44 govern the application, processing, and disposition of petitions for modification.

I. Background

Section 101(c) of the Federal Mine Safety and Health Act of 1977 (Mine Act) allows the mine operator or representative of miners to file a petition to modify the application of any mandatory safety standard to a coal or other mine if the Secretary of Labor determines that:

1. An alternative method of achieving the result of such standard exists which will at all times guarantee no less than the same measure of protection afforded the miners of such mine by such standard; or

2. The application of such standard to such mine will result in a diminution of safety to the miners in such mine.

In addition, sections 44.10 and 44.11 of 30 CFR establish the requirements for filing petitions for modification.

II. Petition for Modification

Docket Number: M-2024-003-M.

Petitioner: South32 Hermosa, Inc., 749 Harshaw Rd., Patagonia, AZ 85624.

Mine: Hermosa Mine, MSHA ID No. 02-03398, located in Santa Cruz County, Arizona.

Regulation Affected:30 CFR 57.11052(d) (Refuge areas).

Modification Request: The petitioner is seeking a modification for 30 CFR 57.11052(d), Refuge areas. Specifically, the petitioner is seeking the use of compressed air in lieu of compressed airlines and bottled water in lieu of waterlines.

The petitioner states that:

(a) South32 Hermosa Inc. (Mine ID No. 02-03398) is a green field project located in Santa Cruz County, Arizona. The mine will be an underground open stoping mining method, and the ore zones will be accessed through both a surface decline and a 25 feet diameter vertical shaft. The mine plans to operate 24 hours per day, 7 days per week with plans to employ between 400 and 500 miners across 4 rotations working on 4- to 10-person crews. The mine is located approximately 10 miles southeast of Patagonia, Arizona.

(b) South32 Hermosa Inc. requests approval to use portable MineARC Refuge Chambers with occupancies of 4, 8, 12, 16 and 20 miners. As the MineARC Refuge Chamber is equipped with a minimum of 72-hours of onboard breathable air supply and 2.25 quarts of water per person per day as required by 30 CFR 75.1507(d)(1), South32 Hermosa Inc. seeks relief from having to provide an external compressed air and waterline as required by 30 CFR 57.11052(d).

(c) In support of the Petition, South32 Hermosa Inc. ensures that the proposed alternative is as safe as 30 CFR 57.11052(d) by the following means:

(1) The reliability of the refuge is enhanced by making it self-contained as the source of water and air would not be dependent on the installation of external airlines or waterlines that would be susceptible to rock fall, fire, or mechanical damage in an emergency.

(2) Waterlines in the mine would not be potable and therefore not drinkable. Supplying onboard water ensures refuge occupants do not succumb to dehydration.

(3) The compressor feeding the compressed air lines shall be located on the surface, which is more than 2,500 vertical feet to the refuge. Over this distance there is substantial pressure loss making it difficult to provide 12.5 cubic feet per minute (cfm) of breathable air for each person as required by 30 CFR 7.506(c). Supplying onboard breathable air for a minimum of 72 hours guarantees oxygen and carbon dioxide levels remain within requisite limits respectively.

(4) The portable refuge chambers are designed to be moved regularly to be as close as possible to the miners' work locations. This ensures that miners have quicker access to a refuge chamber in the event of an emergency.

(5) Internal/external gas monitoring ensures occupants can maintain breathable air inside of the refuge and monitor the conditions outside in case of a need to exit the refuge.

(6) A split-system air conditioning system ensures that the internal apparent temperature remains below 95 °F regardless of the mine temperature.

(7) An airlock significantly reduces the risk of carbon monoxide entering the refuge and ensures mine rescue crews do not need to barricade into a potentially unknown atmosphere.

(8) A carbon monoxide scrubbing system removes any carbon monoxide brought inside during the entry process from the occupants.

(9) Permitting the use of compressed oxygen and carbon dioxide scrubbing ( print page 96693) and onboard water improves the portability of the refuge area, allowing the flexibility of installing refuge areas near the working areas in the mine.

(10) Locating portable refuges throughout the mine where they can be reached within 2,500 ft exceeds 30 CFR 57.11050(b).

(d) The mine is not yet in operation and there are currently no MineARC refuge chambers onsite. If MSHA needs to view a refuge chamber as a part of its PFM investigation, one can be made available to view at MineARC Systems' facility in Dallas, Texas.

(e) The Petitioner asserts that the alternate method proposed will at all times guarantee no less than the same measure of protection afforded the miners under the mandatory standard.

The petitioner proposes the following alternative method:

(a) Refuge areas shall be:

(1) Of fire-resistant construction, preferably in untimbered areas of the mine;

(2) Large enough to accommodate readily the normal number of persons in the particular area of the mine;

(3) Constructed so they can be made gastight; and

(4) Provided with compressed air lines, waterlines, suitable hand tools, and stopping materials.

(b) The MineARC Refuge Chambers shall provide the same measure of protection afforded to miners by the standard by including the following features:

(1) A flame-resistant exterior steel structure.

(2) An entry door with double locking handles and seals on all four sides.

(3) An airlock with a supply of high pressure compressed air cylinders (Grade D) capable of providing 2 x volumetric flushes per entry.

(4) One-way pressure relief valves to limit the internal pressure to less than 400 pascals (Pa).

(5) A supply of 1.32 cubic feet of compressed oxygen (aviator's) per hour per person for the rated duration of refuge as required by 30 CFR 7.506(d)(2).

(6) A primary and backup flowmeter for regulating the flow of oxygen inside the refuge.

(7) Pre-packaged carbon dioxide removal chemicals capable of removing carbon dioxide at the rate of 1.08 cubic feet per person per hour for the maximum rated occupancy and duration as required by 30 CFR 7.508(a)(2)(ii).

(8) Pre-packaged chemical for the removal of carbon monoxide for the rated duration.

(9) Internal atmosphere monitoring for apparent temperature, oxygen, carbon dioxide, and carbon monoxide.

(10) External gas monitoring for oxygen and carbon monoxide.

(11) Drinking water supply of 2.25 quarts per person per day for the rated duration as required by 30 CFR 75.1507(d)(1).

(12) Emergency food rations supply of 2,000 calories per person per day for the rated duration as required by 30 CFR 75.1507(d)(1).

(13) A split system air conditioning system to maintain the internal temperature below an internal 95 °F Apparent Temperature as required by 30 CFR 7.504(b).

(14) A 20-pound multipurpose dry chemical fire extinguisher.

(15) A first aid kit that complies with MSHA Standard 30 CFR 75.1713-7.

(16) Repair materials and tools in case there is any damage during use.

(17) A means of communication with the surface ( e.g., radio, phone).

(18) An uninterruptible power supply (UPS) battery backup system designed for the rated duration.

(19) A 5-gallon chemical toilet for human waste.

(20) Written operating instructions for activating the refuge in an emergency.

(c) Each refuge shall be examined regularly per the manufacturer's instructions. This includes the below intervals.

(1) Weekly Inspection:

(i) Confirm entry door tamper proof seal is in place.

(ii) Ensure external status lights are correct.

(iii) Check for damage and walk-around exterior.

(iv) Check expiration dates of consumables (decal viewable from outside of refuge via portal window).

(2) Bi-Annual Inspection:

(i) Replace one way pressure relief valves.

(ii) Confirm operation of all life support systems.

(iii) Check pressures for all compressed air and oxygen cylinders.

(iv) Confirm quantities and expirations of all consumables.

(v) Load test batteries.

(vi) Calibrate gas monitors.

(vii) Service air conditioning system.

(viii) Test communication system(s).

(d) Every miner at Hermosa shall be trained on the use and operation of the refuge chamber at least bi-annually. This shall include the following:

(1) Watching the manufacturer's operator training video.

(2) Instructions on when to deploy the refuge chamber.

(3) Being aware that interior carbon dioxide levels shall maintain less than 1 percent.

(4) Being aware that the interior oxygen levels shall remain between 18.5 percent and 23 percent.

(5) Hazards associated with compressed oxygen systems.

(6) Where to locate items such as first aid, repair materials, and communications inside the refuge.

(e) MineARC Refuge chambers, with capacities ranging in size from 4 to 20 miners and a rated duration of 72 hours, shall be utilized. Each refuge shall be conspicuously labelled with `REFUGE' and the maximum designated number of miners on the front wall.

(f) The MineARC models shall be selected dependent on number of mine workers in each area of the underground mine. Refuge chambers shall be strategically located underground considering the higher of the below criteria:

(1) The amount of personnel underground at any one time considering additional capacity for visitors, geologists, engineers, and management, etc.

(2) A maximum travel distance of 2,500 ft to any refuge chamber.

(g) Prior to locating a portable refuge chamber the location shall be examined for the following:

(1) Located a safe distance away from any hazardous areas that are potentially explosive or a fire source such as:

(i) Explosive magazines or storage containers.

(ii) Electrical transformers.

(iii) Fuel storage facilities.

(iv) Blasting operations.

(v) Vehicle parking bays.

(2) Located in competent ground (the surrounding area examined for faults, fractures, and dykes).

(3) Located where water cannot accumulate.

(4) Located in a position that does not expose the refuge chamber to vehicle or machinery damage.

(5) Posted with directional signs and/or a green light leading to the refuge location.

(6) Before being placed back into service, the refuge shall be examined for any damage.

(h) The introduction of any new piece of equipment shall be evaluated in terms of the mine's emergency response plan and safety of the miners.

(i) Permanently built refuge chambers shall be on the main intake haulages. These permanent refuges shall include all of the same features as the portables except for using bulkhead walls to seal a dead-end heading in lieu of an exterior steel structure.

(j) Applicable revisions or appropriate changes to the MSHA 30 CFR part 48 training plan regarding the conditions in ( print page 96694) the Proposed Decision and Order granted by MSHA shall be submitted to the MSHA District Manager for revision and approval prior to implementation of the training plan by South32 Hermosa.

(k) The Petitioner asserts that this Petition for Modification of Application of Mandatory Standard has been posted on the mine bulletin board at the Hermosa Mine as of October 17, 2024, and there are no representatives of miners at this operation.

In support of the proposed alternative method, the Petitioner has also submitted: a schematic diagram of a typical MineARC refuge chamber, a table of MineARC refuge chamber models, a table of fire hazards in the mine, a mine map showing locations of initial refuges, a MineARC refuge chamber layout drawing example, MineARC refuge chamber operating procedures, and a MineARC refuge chamber brochure.

The Petitioner asserts that the alternate method proposed will at all times guarantee no less than the same measure of protection afforded the miners under the mandatory standard.

Song-ae Aromie Noe,

Director, Office of Standards, Regulations, and Variances.