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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
April 2006

High Voltage Line Contact

On April 26, 2006, an elevated truck bed contacted an energized 69,000 volt high voltage line at a surface area of a District 8 underground coal mine. While there was no injury to the truck driver, the haul truck sustained two ruptured tires.
       A haul road was being constructed at a slope sinking construction site and extended under a 69,000 volt high voltage line. The truck driver was spreading gravel with the cargo bed of his truck raised when the contact with the high voltage line occurred. The resulting electrical fault ruptured two tires on the haul truck before the power company's protective circuit breaker opened. The truck driver stayed inside the truck until the power company was contacted and it was verified that the high voltage line was de-energized and would remain de-energized. Most utility protective circuit breakers are set to automatically re-close multiple times after an electrical fault first occurs. Fortunately, this circuit breaker was not set to re-close. These high voltage lines served power to the adjacent underground mine, which had to be evacuated because the mine had lost power to their mine ventilation fans.

Overhead Power Line

BEST PRACTICES

  • If contact with high voltage lines has occurred, stay inside the truck or the piece of surface equipment until power is removed from the high voltage lines that the equipment has contacted.
  • 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 lines 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.
  • Use instrumentation to determine height of power lines before performing work close by.
  • Use instrumentation to 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.

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This file was last updated on 05/18/2006

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.