Two miners were missing and possibly trapped Tuesday hours after a wall collapsed onto heavy equipment at a surface coal mine in Maryland.
Rescue crews were on the scene at Tri Star Mining Inc. There were few details about the collapse.
"Our first priority is to rescue the trapped miners," said Amy Louviere, a spokeswoman for the Mine Safety and Health Administration in Washington.
Early reports pointed to a high wall collapse, she said. Louviere described the wall as being 100 feet (30.5 meters) to 125 feet (38 meters) high.
Europe has recognised the need for negotiations with Russia to discuss the security system on the continent. Russian Foreign Minister Sergei Lavrov is going to Macedonia for meetings with colleagues within the OSCE