Collector 4 Pipes to channel nitrose (think nitro glycerine) infused acid through the building. Related Similar Images ...based on the tags: black&white, bolts, chutes, numbers, pipes... Unit 4’s lower levels. Wagons and horses were kept in the building on the left, separate from the rest of the complex in case of fire. In the distance is the boiler house, separate for the same reason. The Engine House’s boiler, which would have been fired all day all day, virtually from the day the shop opened until the day it closed. While it looks like ground level, everything here is one story above the actual earth. Frankie on the White Pine Mine vehicle access shaft. The mine was traditional inside… all room-and-pillar. Ben. The last of four radar domes on the base. The bricks routinely fell from the walls, like seeds falling from trees. On a smaller scale, new walls grew from the floors. A wounded flour mill, muscled into the corner to keep out of the way.