The Mine Safety and Health Administration said the worker was crushed against the wall of the mine while helping to move a roof bolting machine.

The machines are used to drive steel bolts into the roofs of coal mines, typically shale or sandstone, to anchor the overhead rock.

The MSHA is yet to name the miner but has begun its investigations into the incident.

A spokesman from the Illinois Department of Natural Resources said it was also conducting an investigation.

Mine operator Foresight Energy has not yet released a comment on the incident.

The fatality is the sixth coal mining death this year and the third just this week.

On Monday, two West Virginia miners were killed at an operation owned by Patriot Coal.

The miners died while retreat mining, a practice in which miners systematically cut away coal pillars that support the mine roof.