SECURITY OFFICER WAS PATROLLING THE MINE SITE WHEN UNKNOWN SUSPECT(S)- PROBABLY ILLEGAL ALIENS- BEGAN STONING HIS TRUCK. WHEN HE TURNED TO LOOK IN THEIR DIRECTION, THE TRUCK DRIFTED TO THE SIDE OF THE ROAD, WHERE A HEAVY FORKLIFT BLADE WAS STORED. THE OFFICER TRIED TO STOP, BUT PRESSED ACCELLERATOR INSTEAD OF BRAKE PEDAL. THE TRUCK STRUCK THE BLADE, PITCHING DRIVER FORWARD.