Ball Mills Before the gold could be extracted, the rock was turned to powder. Depending on the size of the steel balls inside the mill, the rock would be reduced to a certain size. So, multiple mills were usually used in stages. Related Similar Images ...based on the tags: collapsing, doors, gears, machinery, mills... In the nitrating house. Looking down into the lunch building of an Atlas D, near the motors for the retractable roof. In this design, the roof separates to allow the missile to be erected into launch position. The machine stood the Atlas missile up vertically over the blast pit, launching position, once the roof opened. The balcony used to be beautiful, you say. I say, it still is. A heavy steel rail door to help funnel explosions upward, rather than outward. We know what the ladies’ favorite treats were! Found holding parts on a repair cart. Note the maps still left on the wall. Part of the unremodeled hospital, above the Service Building, where employees would stay sometimes. A massive steel sheer’s equally massive drive cog. Imagine the force.