Doctors treating the survivor of a deadly West Virginia coal mining accident say his condition has improved substantially.

At the Pittsburgh, Pennsylvania hospital treating Randal McCloy, officials say computer scans of the 26-year-old man's lungs and his brain show dramatic improvement. They say Mr. McCloy's injured muscles are improving along with his liver and heart function, and that his brain swelling is reduced.

The families of some of the 12 miners who died in the mine have received goodbye notes their loved ones scribbled while waiting for help. An underground explosion at the mine last Monday filled the air with toxic fumes, forcing 11 of the 12 miners to erect a barricade to try to keep out deadly carbon monoxide. The other trapped miner apparently was killed in the explosion.

Officials are trying to determine the cause of the blast, while families question why it took 40 hours to reach the trapped miners.