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


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Department of Labor
Mine Safety and Health Administration

Accident Info-Gram
JANUARY 2003

Electrical Arc Shocks Maintenance Foreman

Electricity Can KillOn January 16, 2003, a potential fatal electrical accident occurred at an underground mine in District 8. A Maintenance Foreman contacted energized 995-volt conductors inside of a controller enclosure on a Joy continuous miner. He spent one night in the hospital. His only injury was a small cut on his right index finger.

Malfunctioning for several shifts, the Joy continuous-miner's scrubber motor had been "dropping-out" intermittently, causing the cutter head to shut off. Near the end of the day shift, the Maintenance Foreman and the Section Mechanic decided to open the main (left-side) controller enclosure to repair the problem. The Maintenance Foreman instructed the Miner Operator to trip the main circuit breaker on the miner. The Miner Operator inadvertently de-energized the control and light circuit breaker. The Maintenance Foreman removed the arc chute from the scrubber-motor line starter. He was using a screwdriver to inspect the scrubber-motor line starter when an electrical arc occurred, and the Maintenance Foreman received an electrical shock.

The qualified Maintenance Foreman failed to de-energize, lock, and tag the power supply circuit to the continuous miner before removing the main-controller enclosure cover. His performance of electrical work on an energized circuit resulted in a near miss accident that could have easily caused a fatality.

BEST PRACTICES
  • The qualified electrician doing the work must ensure that equipment is de-energized, locked and tagged out.
  • Troubleshooting and testing energized circuits must be performed only when the purpose is to determine voltages and currents and does not include the repair of the electrical problems.
  • Gloves, in accordance with §75.1720(c), are required whenever qualified persons troubleshoot or test energized electric power circuits or electric equipment.
  • Lock out and tag equipment power supply circuits before removing controller enclosure covers.

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This file was last updated on 2/20/2003

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.