Updated 3/24/2013:
I've been making progress on the Standard Slag module. Photo 1 show a set of steel pilings (center) that I have placed but not glued. What's new is the foundation piece at the bottom of the stack that brings the pilings to the correct level. This section also protrudes a bit from the wall to the right. That wall will hold up a slipping embankment.
The second photo shows the steel pilings that will occupy the pink foam wall to the left in Photo 1. This set of pilings has been glued to a piece of cardboard which will then be positioned and secured in place.
Photo 3 shows the inside of the Open Hearth mill. Looking up you can see the smokestacks protruding through the roof. The circuit board for the animation will probably set under the smokestack platform to the left.
George