EE WAS PREPARING TO CONDUCT MAINTENANCE ON THE CONVEYOR BELT SYSTEM. AS PART OF THE PROCEDURE, THE COUNTERWEIGHT IS LIFTED BY FORKLIFT AND CHAINED/SECURED TO RELEASE THE COUNTERWEIGHT FROM BEL T. EE WAS PREPARINGTO SECURE THE COUNTERWEIGHT WHEN IT SLID BACK-WORDS ON THE FORKS APPROX. 4.5 M ABOVE GROUND AND PINNED HIS FEET TO THE MAST OF THE MACHINE.