Ball and Rod Mills Tucked-into the side of the concentration mill… these machines were meant to crush underground rock into a fine dust for mineral extraction. Related Similar Images ...based on the tags: dirty, heights, machinery, mills, wheels... On the middle level of the Poacher House. For a detailed view of the chart see ‘See Reverse’. A clicky-flippy clock is having some kind of malfunction. A massive steel sheer’s equally massive drive cog. Imagine the force. Unit 4’s lower levels. Heavy wood doors for keeping people in. The mill is one of the tallest buildings in the city. It’s too bad that the cupola with its big skylights and flagpole were removed. This belt-run axle ran a turbine (now gone) to blow fresh air into the mine. The tops of the coke stoves. This “pit” would allow workers to crawl below locomotives to service them.