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Sandia Technology logo A quarterly research and development magazine

Summer 2007
Volume 9, No. 2

SANDIA TECHNOLOGY MAGAZINE

Tragedy strikes, cont.

Clear results

poplar tree
The National Lightning Detection Network recorded lightning strikes near the mine area at the time of the accident. One strike may have hit this poplar tree.
The study concluded that it is highly unlikely electromagnetic energy from the strike traveled along conductors through the mine and into the sealed area to ignite the explosion. However, electromagnetic energy from a significant lightning event at the surface, above the sealed area, could have traveled through the ground to create high voltage in the sealed area, subsequently creating a spark that ignited flammable methane mixtures.

“The results of field measurements and analytical modeling were clear — lightning can propagate significant electrical energy into mine systems under the right conditions,” says Schneider.

He says mine safety might be improved with a better understanding of this phenomenon in the variety of scenarios seen in the U.S. mining system.

“I can readily envision this leading to additional, reasonable preventive measures to reduce the probability of such a catastrophic event in the future,” he says.

MSHA’s report on the Sago Mine accident is online at www.msha.gov.

Technical contact: Larry Schneider, (505) 845-7135, lxschne@sandia.gov
Media contact: Chris Burroughs, (505) 844-0948, coburro@sandia.gov