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U.S. Department of Labor

Mine Safety and Health Administration
201 12th Street South, Suite 401
Arlington, VA 22202-5450

EFFECTIVE DATE:  07/26/2012 EXPIRATION DATE: 3/31/2024      

LAST VALIDATED: 03/31/2021


                    Administrator for
                    Coal Mine Safety and Health

                    GEORGE TRIEBSCH
                    Director of Technical Support

SUBJECT:     District Field Change Requests for Adding Proximity Detection Systems

This Procedure Instruction Letter (PIL) is intended for Coal Mine Safety and Health personnel.

The purpose of this PIL is to guide Mine Safety and Health Administration (MSHA) inspection personnel who receive mine operator requests to add proximity detection systems to MSHA-approved mining machines.

Procedure Instructions
Proximity detection is a technology that uses electronic sensors to detect motion or the location of one object relative to another. Proximity detection systems can provide a warning and stop mobile machines before a pinning, crushing, or striking accident occurs that could result in injury or death to miners.
Underground mining machines equipped with proximity detection systems must be approved by MSHA as permissible equipment under Title 30 Code of Federal Regulations (30 CFR) Part 18 (for electrical machines) or Part 36 (for diesel machines) before they can be used in gassy areas of underground coal mines.

There are several avenues in the approval and installation process of a proximity detection system:

  1. MSHA offers an optional program allowing proximity detection manufacturers to obtain acceptance of their proximity detection system. This program is referred to as the Proximity Detection Acceptance (PDA) program and results in the issuance of a PDA number to a proximity detection system that has met the applicable requirements of Part 18.
  2. Machine manufacturers with MSHA approvals may submit an application to MSHA’s Approval and Certification Center (A&CC) to add a proximity detection system to their approval. The machine manufacturer can submit a new approval request, an extension of approval request, or a RAMP (Revised Approval Modification Program) request to the A&CC to add the proximity detection system to the machine.
  3. The mine operator can submit a field modification request to the A&CC to add a proximity detection system to the machine(s) they own.
  4. For electrical machines, the mine operator can also submit a district field change request to the Coal Mine Safety and Health (CMS&H) District Office to add a proximity detection system accepted under MSHA’s PDA program to a MSHA-approved machine it owns.

The Coal Mine Safety and Health Electrical Inspection Procedures Handbook addresses district field changes. It provides a list of changes that can be made without sending an application letter to the A&CC, without processing a written field change report and acceptance letter, and without a visual inspection at the time of installation. This handbook will be revised to include the addition of proximity detection systems to approved mining machines as an acceptable district field change.

When requesting a district field change, coal mine operators are required to notify the district office in writing that the changes will be made in accordance with 30 CFR Part 18. A copy of all notifications shall be maintained in the appropriate mine file. Inspection of such changes shall be made as soon as practicable, but not later than one month after receipt of the notification. A record of such inspection shall be maintained in the mine file.

When processing a district field change, CMS&H enforcement personnel should evaluate the request to determine whether the field change is adequately described or whether additional assistance from the A&CC is necessary. If A&CC assistance is required, the district should contact Robert Holubeck at 304-547-2088,

The Mine Safety and Health Administration anticipates that it will receive requests from manufacturers and mine operators to add proximity detection systems to MSHA approved machines.

The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq., 30 CFR § 75.500(c) Permissible Electric Equipment and § 18.81 Field Modification of Approved (Permissible) Equipment.

Internet Availability
This PIL may be viewed by accessing the MSHA home page and selecting "Procedure Instruction Letters" under "Compliance Information."

Issuing Offices and Contact Persons
Technical Support
Robert Holubeck, (304) 547-2088

Mine Safety and Health Enforcement, Safety Division
Rodney Adamson, (202) 693-9549

MSHA Program Policy Manual Holders
Manufacturers of Mining Equipment and Mine Equipment Repair Facilities
Miners' Representatives
Underground Coal Mine Operators
Underground Independent Contractors
Special Interest Groups