Arc Flash & Electrical Safety

Wednesday, May 30, 2007

Mine Blast Kills 39 Workers

This news item caught my eye because I've just returned from a 12 day trip to Russia. Last Thursday an explosion in a Russian coal mine resulted in the death of 39 workers. This is the second major coal mining disaster in Russian in the past two months. In March a coal mine explosion resulted in the deaths of 110 workers.

What was the cause of this most recent tragedy? The Moscow Times reports:

"Alexander Sekachyov, spokesman for the agency's Southern Federal District office, said a preliminary investigation of the affected coal faces in the Yubileinaya mine revealed that a power cable had become detached from a coal-cutting machine, electrifying its exterior. This resulted in an electric arc or a spark that produced the initial blast, which then ignited coal dust in the mine, he said."

Labels: Electrical Safety, Mining

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Monday, January 22, 2007

Arc Flash Protection In The Mining Industry

Because of the unique requirements of mining the underground mining industry has not been required to comply with NFPA 70E. This has been recognized as a problem because arc flash is a significant source of injuries in underground mining. A report published by NIOSH states:

"Between 1990 and 2003, 2,326 traumatic mine electrical injuries occurred. The largest single category of electrical injury was burns from electrical arcing, which accounted for 893 (38%) of all electrical injuries. Electrical burn injuries of all types accounted for more than 21,500 lost work days."

Why was there such a significant problem. Mainly because arc flash hazards were not recognized as being a problem. The NIOSH report states:

"Findings thus far indicate a general lack of awareness of common arc-flash hazards in the mining industry. Accident reports show that two-thirds of arc-flash injuries involve circuit breakers, cables, hand tools, meters, and plugs. The equipment and PPE needed for safe troubleshooting in arc-prone situations are seldom used. Circuit breakers are often operated beyond their design parameters and many are repaired by third-party rebuilders using substandard components."

As a result NIOSH is creating a program to address arc flash hazards in the underground mining industry. The NIOSH report states:

"This project will produce practical guidelines to determine arc flash boundaries in mines and prep plants. Recommended improvements in work practices regarding the use of hand tools, meters, PPE, and other engineering controls will increase miners’ understanding of arc-flash hazards. Training guidelines will show how to most effectively present this information to the mining audience."

Labels: Arc Flash, Mining, NFPA 70E, NIOSH, Work Place Safety