Federal and state investigators examined a West Virginia underground coal mine yesterday and questioned workers about the death of a miner who was struck on the head by a wooden plank.

Todd Upton was killed Wednesday while operating a piece of heavy equipment inside the Sycamore No. 2 mine in Jarvisville, near Clarksburg.

But Caryn Gresham, a spokeswoman for the West Virginia Office of Miners' Health, Safety and Training, and officials with the federal Mine Safety and Health Administration said they were not sure how long the investigation would take to determine why the plank hit him.

Mr. Upton, 34, was the 19th miner to die this year in West Virginia. Officials said he was killed around 2:30 p.m. when a 12-foot-by-9-inch-by-3-inch plank struck him as he was operating the scoop near the mine entrance.

Mr. Upton, who lived near Fairmont, W.Va., was pronounced dead at 3:25 p.m. at Ruby Memorial Hospital in Morgantown, W.Va. He was a section utilityman and had worked as a miner for less than a year, according to MSHA's preliminary report on the accident.

The mine, which employs 94 people, is owned by International Coal Group's Wolf Run Mining Co., which took control of the site May 12. ICG also owns the Sago mine near Tallmansville, W.Va., where 12 miners died and another was seriously injured in January.

ICG officials did not respond to requests for information about the accident yesterday, instead re-releasing a statement issued Wednesday after Mr. Upton was killed.