EMPLOYEE WAS WALKING FROM THE SHUTTLE CAR TO THE RIGHT BOLTER. CONDITIONS WERE WET AND MUDDY. EMPLOYEE STEPPED ON A LUMP OF COAL AND HIS FOOT SLID SIDEWAYS TWISTING HIS ANKLE. HE WAS TRANSPORT ED TO THE HOSPITAL AND DIAGNOSED WITH A FRACTURE TO THE TOP OF HIS RIGHT FOOT. EMPLOYEE REFUSED A CAST AND CAME BACK TO WORK AT HIS REGULARLY SCHEDULED SHIFT.