I'm a big fan of Paper Mills, but there are several kinds of paper mills. There are the regular white paper mills that produce various types of white writing/printer/copier papers. There are Kraft Mills that make brown paper used in paper bags, boxes, cardstock. There are newsprint mills that make newsprint. and Tissue mills that make toilet paper and paper towels. I've been working on two mills, one at home and another on my club layout.
This is a Kraft Mill on a 3'x8' module I have at home. The warehouse is in the distance. There is a rotary dumper on the right end of the module.
These next two photos come from the Corvallis Society of Model Engineers in Adair Village, OR. This first mill is typical of a newsprint mill.
And a Truck dump.