The Mine Safety and Health Administration (MSHA) announced in a press statement the publication of a final rule in theFederal Registerrevising the agency’s electrical design requirements for the approval of high-voltage continuous mining machines. The rule also establishes additional safety standards to address the machines' installation, use and maintenance in underground coal mines. MSHA's existing standards do not address high-voltage continuous mining machines. Although this equipment has been used in underground coal mines since the late 1990s, mine operators must submit a petition for modification to use it.

Since 1997, MSHA has granted 52 PFMs — with specific conditions — to allow mine operators to use high-voltage continuous mining machines underground. Currently, there are 27 high-voltage continuous mining machines operating under PFMs in eight underground mines. Significant improvements in the design and manufacturing technology of high-voltage components provide for the use of high-voltage continuous mining machines with enhanced safety protection against fires, explosions and shock hazards.

"Compliance with this regulation will reduce the potential for electrical-related fatalities and injuries associated with high voltage continuous mining machine use," said Joseph A. Main, assistant secretary of labor for mine safety and health. "It also will reduce the need to file a petition for modification."

Key features of the final rule include the following:
  • Provides for MSHA approval of high-voltage continuous mining machines, including better design and construction criteria and improved ground-fault protection. Approval ensures that the systems will not introduce an ignition hazard when operated in potentially explosive atmospheres.
  • Establishes mandatory electrical safety standards for proper installation of high-voltage continuous mining machines, electrical and mechanical protection of equipment, handling trailing cables and performing electrical work.
  • Preserves safety and health protections for miners while facilitating the use of advanced equipment designs.
    • Greater protection against electrical shock, cable overheating, fire hazards, and back injuries and other sprains caused by handling trailing cables.
    • Increased safety requirements to eliminate or minimize unsafe work and repair practices, such as handling lighter cables.