Company official Meg Gallagher said Chad Wayne Meyers, 30, was operating a continuous miner unit at the Willow Lake operation near Equality, Saline County, when he became pinned by the unit.
The CM operator died about 5am local time, added US Mine Safety and Health Administration spokeswoman Amy Louviere in a statement to ILN.
It was not clear if the victim was pronounced at the scene.
Both confirmed Willow Lake had been idled pending an investigation.
MSHA confirmed federal officials from its District 8 office were onsite Saturday.
“Willow Lake deeply mourns the loss of a fellow employee and expresses its sympathies to family members, co-workers, and friends,” Peabody officials said.
The 460-worker Willow Lake mine, which first shipped coal in 2002, produced 2.2 million tons in 2011.
The complex sells the coal from the Springfield No. 5 seam to Midwest utility generators.