Lots of Dump Trucks

The following is from a DRN news release.

In the test of on-site materials, AmerenUE will use the rock from the existing site. The rock will be transported offsite to a commercial quarry operator and crushed to design specifications before its delivered back to the site. The crushed rock will be mixed with cement, fly ash and water in a mixer to produce concrete. The permit allows AmerenUE to construct concrete pads to test the feasibility of the Roller Compacted Concrete Mix Design Program developed to rebuild the Taum Sauk upper reservoir.

So I assume that the trucks heading to Ironton (home of a commercial quarry) are full of large rocks from the old reservoir and the trucks heading back to the Taum Sauk site are full of crushed aggregate.