Western Scale Models produced some great kits for modeling industrial equipment. 

Here is an O scale 10 stamp mill for processing ore.

The 10 stamp battery, the rock crusher and the Challenge ore feeders are kits but the remainder of the mill and it's design is my own making.

The model is not finished but it gives you the idea of what the interworkings of a 10 stamoremill looked like.

Outside of shop during the day light.

I have always enjoyed the blacksmith shop at Knotts Berry Farm so I decided to build my version in O scale.

Outside the blacksmith shop at night looking in.