http://d.yimg.com/a/p/ap/20100406/ca...HeUaWteQST3g--AP - The coal mine rocked by an explosion that killed at least 25 workers in the nation's deadliest mining disaster since 1984 had been cited for 600 violations in less than a year and a half, some of them for not properly ventilating methane — the highly combustible gas suspected in the blast.
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