The Building of the Mine Tunnel
The interior of the mine tunnel was built as a pre-fabricated module that would later be inserted into a rough opening in the mountain. It started with a cedar frame. Note the wedge shape and decreasing size of timbers toward the smaller end. The smaller timbers are also spaced closer together.
The wedge shape, size, and spacing of the timbers is a deliberate optical illusion to make the tunnel seem deeper than it really is.
A typical tunnel portal was built of miniature timbers.
Carved and painted foam was used to create the rock walls and ceiling of the tunnel.
This is a fit check to be sure the compressed air locomotive fits nicely in the tunnel.
The far end of the tunnel is simply a foam wall. It needs to end somewhere.
The tunnel needs to end somewhere, but it doesn't need to look like it ends. The above photo looking into the tunnel without a finished end was Photoshopped with multiple copies inside copies to create an "infinity" image. This resulting image was then glued to the wall at the end of the tunnel. There is now no visible end to the tunnel.
This is a fit check of the finished tunnel module in the rough cut of foam that is turning into a mountain.
Here is the finished mountain complete with compressed air locomotive and ore cars on the tunnel track. There is a loading tower on the right. The little building just outside the tunnel is the compressor shack. The compressed air locomotive needed to get charged up somewhere, and that was usually done with a steam powered air compressor somewhere outside of the mine.