Three employees were assembling a mast for a mobile rig derrick. Each of the two sections are approximately 60 feet long. The lower mast was positioned on stands. The upper mast was supported by an overhead crane. The injured employee was standing at the base on the lower mast behind the winch skid. He was using a crane and a winch that is mounted on a forklift skid to slide the top mast into the lower mast. The upper section of the mast became misaligned and the force from the crane and winch operations caused the mast to shift 4 feet. This caused the winch skid to shift 4 feet back as well, pinning the employee's left foot between the base of the winch and the base of the forklift mast. The employee sustained two fractures in his foot.