MSHA announces final rule for high-voltage continuous mining machines

The Mine Safety and Health Administration on April 12 announced the publication of a final rule in the Federal Register revising 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.