Skip to content
U.S. Department of Labor

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

EFFECTIVE DATE:   June 20, 2013 EXPIRATION DATE: 3/31/2024          
LAST VALIDATED: 03/31/2021


                    Administrator for
                    Coal Mine Safety and Health

SUBJECT:     Reissue of P11-V-1; Clarification on Repairs or Maintenance of Machinery,
                   30 C.F.R. § 75.1725(c)

Coal mine operators, equipment manufacturers, miners and miners' representatives, Mine Safety and Health Administration (MSHA) enforcement personnel, and other interested parties should have this information.

This Program Policy Letter covers the MSHA policy concerning the requirements of Section 75.1725(c), Title 30 of the Code of Federal Regulations (CFR), in order to prevent injuries while machinery repairs or maintenance are performed.  This policy letter addresses the meaning of 30 C.F.R. § 75.1725(c), and identifies a number of methods for complying with the standard.

Section 75.1725(c) provides that "[r]epairs or maintenance shall not be performed on machinery until the power is off and the machinery is blocked against motion, except where machinery motion is necessary to make adjustments."  "Machinery" includes hydraulic jacks or cylinders, belt conveyors, longwall conveyors, and other machinery used in coal mines.  "Repair" means to fix, mend, or restore to good working order. "Maintenance" means the labor of keeping machinery in good working order and includes clean-up, clearing jammed material or conducting examinations on or in close proximity to machinery.

Methods to comply with this standard to prevent inadvertent or unexpected motion include:

  1. Opening the circuit breaker for the affected machinery, provided no energized parts or conductors are exposed, and placing the run selector switch for startup of the machinery in the "off" position.  On longwall machinery, this would include placing the lockout switch in the lockout position in the area where the repair or maintenance is being performed. (A qualified electrician would be required to de-energize a circuit breaker if there are exposed energized parts or conductors. See Item No. 8, 30 C.F.R. § 75.511, Program Policy Manual, Volume V.)


  1. Opening the circuit breaker at the power center that supplies power for the affected machinery (30 C.F.R. § 75.900) and disengaging the power cable coupler that supplies power to the machinery (30 C.F.R. § 75.903).
  1. Opening a manual visible disconnect switch, either within the circuit or onboard the machinery, (30 C.F.R. § 75.903) and securing the switch against re-energization.  A control circuit start-stop switch does not constitute a manual disconnect.


  1. In cases such as steeply inclined belt conveyors and suspended loads, when removing the power alone will not ensure against unintentional or inadvertent movement, the machinery shall be physically blocked, in addition to removing the power by one of the three methods described above.  Physical blocking may be achieved by the use of such devices as bars, chocks, or clamps.

Other methods may be appropriate in particular situations to prevent unintentional or inadvertent movement.  What method(s) is appropriate depends upon the circumstances and type of machinery.  The critical determination is whether the method(s) used would effectively prevent motion.  The types of maintenance work that can be performed on longwalls and continuous miners are lubrication, changing bits, changing water sprays and conducting respirable dust control parameter checks with the circuit breaker opened that opens all power conductors entering the machine.  Taking air readings on continuous miners equipped with a scrubber to determine compliance and checking water pressure requires the continuous miner to be energized.  Extra precautions shall be taken to prevent injuries such as moving the continuous miner to a crosscut with the cutter head against the inby coal rib and limiting the number of miners exposed when taking air reading on scrubbers and checking water pressure.

In addition, it is important to emphasize that restoring power prematurely while repairs or maintenance are ongoing places a miner performing that work in harm's way.  Operators must prevent inattentive restarting and assure that repairs or maintenance have ceased before power is restored to the machinery.  Preventive measures operators can take include locking and tagging out, clearance checks, or visible or audible alarms with built-in time delays before restart to warn the miner(s) performing the work so power will not be restored without the miner's knowledge.

Miners have suffered serious injuries and fatalities when performing maintenance and repairs on machinery that started up and moved unexpectedly.  Adequate methods to assure the miners' safety must be used while conducting this work.

The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq., and 30 C.F.R. § 75.1725(c).

Internet Availability
This program policy letter may be viewed on the Internet by accessing MSHA's homepage at ( under MSHA’s Major Laws, Regulations and Policies choose "Compliance Information (PIBs, PILs, the PPM, and More” and select “Program Policy Letters.”

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

Coal Mine Safety and Health, Safety Division
Stephen J. Gigliotti, (202) 693-9479

MSHA Program Policy Manual Holders
Miners' Representatives
Coal Mine Operators
Manufacturers of Mine Equipment
Special Interest Groups