|U.S. Department of
Mine Safety and Health Administration|
1100 Wilson Boulevard
Arlington, Virginia 22209-3939
ISSUE DATE: April 16, 2009
PROGRAM INFORMATION BULLETIN NO. P09-07
FROM: LINDA F. ZEILER
Acting Director of Technical Support
KEVIN G. STRICKLIN
Coal Mine Safety and Health
NEAL H. MERRIFIELD
Acting Administrator for
Metal and Nonmetal Mine Safety and Health
SUBJECT: Neutral Start Methods on Mobile Electrical Equipment
Who needs this information?
Mine Safety and Health Administration (MSHA) enforcement personnel, coal and metal and nonmetal both surface and underground mine operators, miners' representatives, equipment manufacturers, and repair shop facilities.
What is the purpose of this Program Information Bulletin (PIB)?
The purpose of this PIB is intended to inform interested parties of a potential hazard that can be eliminated by providing a neutral start method on mobile electrical equipment.
A. What is a neutral start method?
A neutral start method is a design feature which ensures that machines cannot be started unless the drive (tram) control is in neutral. This ensures that motor torque will not be transmitted unintentionally to the drive motors and cause machine movement when electrical power circuits are energized on the machine.
B. Why is a neutral start method needed?
The lack of a neutral start method can create a dangerous condition for persons working in the vicinity of equipment who might be caught unaware by the sudden movement of the equipment when the equipment becomes energized. Without a neutral start feature, it is possible to start a machine and deliver power to the driving mechanism resulting in unintentional movement of the machine before the equipment operator is in total control of the machine. This hazard applies to machines with direct-drive electric motors, as well as machines utilizing fluid power or other systems for the drive mechanism. For this reason, MSHA recommends that mine operators and equipment manufacturers equip all mobile electrical motor-driven machines with a neutral start feature as soon as possible. If the equipment being modified is permissible, the approval holder or mine operator should contact MSHA's Approval and Certification Center to ascertain whether the equipment modification affects the permissibility of such equipment. For further guidance, contact equipment manufacturers on this matter.
What is the background for this PIB?
A recent coal mine accident occurred while a shift foreman was preparing to tram a belt feeder after a belt move. When the feeder was energized, it started the driving mechanism which caused unintentional and uncontrolled machine movement resulting in the machine abruptly pivoting and pinning the victim between the feeder and the coal rib. This accident and other similar accidents could have been prevented if the machine involved had incorporated a neutral start feature.
The incorporation of a neutral start feature is believed to have a minimal impact on retrofitting electrical equipment in the field. Neutral start features have been successfully incorporated into underground permissible diesel-powered equipment for over 25 years and should also be incorporated into other mobile electrical equipment. Several manufacturers already have incorporated electrical circuits to prevent tramming of equipment if a directional control or footswitch is activated unintentionally during start-up. Other pieces of equipment have incorporated circuits to prevent a hydraulic motor from starting unless the directional control for the electric tram motors is placed in the "off" or "neutral" position when the hydraulic motor is energized. Additionally, it is possible to devise a neutral start feature through a mechanical linkage which would prevent the ability to start the machine unless the tram controls are placed in a "neutral" position.
What is MSHA's Authority for this PIB?
The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq., 30 C.F.R. §§ 18.20(b), 57.22302, 57.22303, 57.22304, 57.22305, 75.1725, and 77.404.
Is this PIB on the Internet?
This bulletin may be viewed on the Internet by accessing MSHA's home page (http://www.msha.gov) and then choosing "Compliance Info" and then clicking on "Program Information Bulletins."
Who are the contact persons for this PIB?
Coal Mine Safety and Health, Safety Division
Salwa El-Bassioni, (202) 693-9525
Metal and Nonmetal Safety and Health, Safety Division
Lawrence Trainor, (202) 693-9644
Technical Support, Approval and Certification Center
Robert C. Boring, (304) 547-2089
Who will receive this PIB?
MSHA Program Policy Manual Holders
MSHA Special Interest Groups
Surface and Underground Coal and Metal and Nonmetal Mine Operators
Manufacturers of Electric Mining Equipment