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District 8 - Coal Mine Safety and Health
Info-Grams and Close Call Accidents


Info-Grams
Close Call Graphic
Department of Labor
Mine Safety and Health Administration

Accident Info-Gram
March 2004

Track Hoe Causes Electrical Arc Incident

Recently, a contractor at a southern Illinois surface mine was working below energized high-voltage lines when his track hoe came close enough to the overhead lines to cause an electrical arc, short circuit. The contractor was operating a Cat 330L track hoe placing and moving rip rap on a drainage ditch. The overhead power lines were energized at 69,000 volts and were located approximately 21-feet above the ground. The operator estimated he was not close enough to contact the overhead power lines. A large flash occurred and the power to the preparation plant, synfuel plant, and adjacent underground mine was interrupted. There were no injuries or property damage as a result of this close-call incident.

Mark Overhead LinesOverhead Power Lines

BEST PRACTICES
  • Recognize potential hazards. Train workers to "Look up" prior to starting work.
  • Install physical barriers under overhead lines.
  • Erect signs to identify a danger zone.
  • Raise problem sections of overhead line to at least 40 ft. above ground.
  • Have the electric power utility company install insulating barriers or sleeve conductors where equipment must operate.
  • Have high visibility spheres installed on energized lines to help make the line location obvious to all workers.
  • Have the electric power utility company temporarily de-energize the power lines.
  • With instrumentation determine height of power lines before performing work close by.
  • 77.807-2 requires booms and mast shall not be operated within 12 feet of an energized 69 KV line.
  • Electric power utility companies will reclose 3 times. If power lines are contacted, stay in or on equipment until power is off.

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This file was last updated on 3/29/2004

This information was provided by concerned miners in an effort to eliminate accidents. Accident or "close call" information within District 8 may be shared by contacting the MSHA office at (812) 882-7617.