The operator of the West Virginia mine that exploded on Monday, killing at least 25 people, was warned by federal officials just over two years ago that it could be cited for having a "pattern of violations," which would have allowed far stricter federal oversight of the mine. But the mine escaped the stepped-up enforcement even though it continued to amass violations, federal records show.

Search teams had to abandon another effort at around 5:30 a.m. on Friday to search the Upper Big Branch mine, just as they resumed the search for four missing miners. Gov. Joe Manchin said rescuers ran into some difficult conditions in the mine and had to retreat.

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