Abstract: At 2:30 p.m. on November 28, 2006, Employee #1 was tightening the bolts of the column base of a Boring Mill while an engineer was manually cycling the tool-changer assembly, standing freely in the upright position on the concrete floor approximately 8 feet away from the column. As the tool-changer arm cycled and swung around, the entire assembly toppled towards the column and pinned Employee #1 against the column causing serious injuries. The tool-changer assembly was freely standing for four days and was detached from overhead crane without verifying that the assembly had been secured or supported to prevent inadvertent movement. Employee #1 worked for a week for this employer as a maintenance assistant.