国际英语新闻：Explosion at U.S. coal mine kills 6, 21 missing

WASHINGTON, April 5 (Xinhua) -- An explosion at a coal mine near Charleston, West Virginia killed six miners on Monday, and 21 people were reported missing.

Ron Wooten, director of West Virginia Office of Miners' Health Safety and Training, told local media that six miners were dead and 21 others were missing, following an explosion at Upper Big Branch mine in Raleigh County, an underground mine operated by Massey Energy subsidiary Performance Coal Co. The mine is located at about 50 km south of Charleston, capital of West Virginia.

Reports said another 21 miners were evacuated, and they were being treated for injuries. That would put the number of people underground at the time of explosion at 48. The reason of the explosion was unclear at the moment.

Wooten said the explosion occurred at about 3 p.m. Monday. Massey Energy didn't immediately provide further details with regard to the casualties, extent of damage or if there were people trapped inside, saying those numbers are "uncertain" at the time.

Local TV WCHS said dozens of miners are believed to be trapped underground. Emergency crews from the private sector, the State and federal agencies are responding to the incident. Five of them were already on the scene as of Monday evening, including teams from Massey Energy, Conso Energy and the state Office of Miners' Health Safety and Training. Dozens of county and state emergency personnel were on site aiding in rescue efforts.