Federal officials said Thursday they have closed the longwall portion of the Sufco coal mine 30 miles east of Salina, Sevier County, following a Wednesday "bounce" similar to the event that trapped six miners in the Crandall Canyon Mine on Aug. 6.

A bounce describes a collapse or bursting of material underground that can be triggered by geologic pressure inside the mine or by an earthquake.

No injuries were noted in the Wednesday event.

Matthew Faraci, spokesman for the U.S. Mine Safety and Health Administration, said MSHA has sent officials to the mine to investigate.

Arch Coal Inc.'s Sufco mine uses both a longwall mining system and continuous miner units, according to the company. MSHA did not say how much of the mine was affected by the closure of the longwall portion.

Arch Coal did not return calls later Thursday.

The University of Utah Seismograph Stations recorded a 2.8-magnitude seismic event near the Sufco mine Wednesday, but scientists have not said whether an earthquake caused the mine bump or whether a collapse inside the mine caused the seismic reading.

The collapse that trapped six Crandall Canyon miners in August created a 3.9-magnitude seismic reading. A subsequent Aug. 16 bump that killed three rescue workers inside the Crandall Canyon Mine was recorded as a 1.6-magnitude seismic event.

MSHA implied Wednesday's seismic reading was triggered by a mine collapse in saying the longwall section at Sufco will remain closed "until MSHA is assured that this will not occur again."

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