Huntington, Utah (AP) -- Six miners were trapped in a coal mine Monday by a cave-in so powerful that authorities initially thought it was small earthquake.
The miners were believed to be 1,500 feet below ground, about four miles from the entrance to the mine, which is 140 miles south of Salt Lake City.
University of Utah seismograph stations recorded a seismic wave of 3.9 magnitude early Monday, causing speculation that a minor earthquake had caused the cave-in. Scientists later realized the collapse at the Genwal mine had caused the disturbance.
"There is no evidence that the earthquake triggered the mine collapse," said Walter Arabasz, director of the seismography stations.
At least a half-dozen other mine collapses since 1995 have caused similar seismic waves, including one in southwestern Wyoming that caused readings as high as 5.4 on the Richter scale.
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