State Police said a truck spilled 48,000 pounds of coal on KY 904 in Williamsburg on Tuesday afternoon.
The road was closed for two hours while the debris was cleaned up. The road has reopened.
Investigators said Eric Harn, 59, of Industry, Pennsylvania, was driving the truck when it left the road and overturned.
State Police said Harn was wearing his seat belt at the time of the accident.
Investigators said drugs or alcohol were not suspected factors in the crash.