EE HAD FINISHED HIS SHIFT LOADING WASTE COAL TRUCKS WITH A FRONT END LOADER. HE HAD BEEN RELIEVED BY THE DAY SHIFT OPERATOR AND WAS WALKING TO THE CREW VEHICLE WHEN HE TWISTED HIS ANKLE ON THE UNEVEN AND SNOW COVERED COAL SURFACE. LATER THAT DAY, HE WENT TO ADR. AND AN X-RAY WAS POSITIVE FOR A FIBULA FRACTURE.