I remember a particular midnight shift when I was a roof bolter in a coal mine in 1976. We had arrived uneventfully on the section like most every day. I walked up to my machine and prepared for the day's work. As I surveyed the area where the previous shift's crew left my roof bolter, I had an idea. The more I thought about it, the more excited I became. Finally, I saw the light of my foreman, Carl, coming in my direction.