THE ACCIDENT OCCURRED IN #1 SIDE SHAFT COMPARTMENT APPROX. 428'BELOW THE 900 LEVEL. AS THE SKIP WAS LOWERING THE 1ST CREW FROM 1085 TO 50 LEVEL, THE SKIP MAN DOOR OPENED PARTIALLY & STRUCK A SHAFT SET CAUSING THE DOOR TO BE PUSHED UP INTO THE SKIP. THE INVESTIGATION HAS REVEALED THE DOORS LOCK MECHANISM FAILED ALLOWING THE DOOR TO MOVE. MSHA WAS IMMEDIATELY NOTIFIED.