Three construction workers plunged to death in an air shaft of a coal mine in Princeton, Gibson County, Ind. on Friday, CNN reported.

Authorities said a huge "sinking bucket" was carrying the three workers down to the construction site at the bottom of the 183-meter-deep air shaft, which is still under construction.

Suddenly, the bucket lost control and plunged to the bottom of the vertical shaft, killing the three workers instantly.

There were no other casualties and all three bodies have been retrieved.

A representative of the mine said mine officials checked the bucket every day and are trying to figure out what happened.

The workers belonged to a construction company, which is digging a new air shaft for the mine.

The state government has dispatched labor and mine safety officials to the scene to investigate the incident.

According to the website of the Alliance Resource Partners, the mine's parent company, the mine began production in November 2000,with a throughput capacity of 700 tons of raw coal an hour.

In November 2001, a "fatal machinery accident" occurred at the facility, killing one miner, according to federal records.

Friday's incident is the second mining accident in the United States in less than a week.

On Aug. 6, a coal mine in Utah collapsed and six miners were trapped inside.

An initial rescue effort failed Friday and the miners' conditions are still unknown.
 
(Xinhua News Agency August 11, 2007)