More rock crushing. This time I actually went to one of these facilities, where they take aggregate out of the ground, crush it into various sizes, sort it, and sell it to people.
We were doing environmental compliance assessments at the San Antonio Flood Control Basin, near Upland, CA, in the foothills east of Los Angeles. One of the facilities that we had to visit happened to be this aggregate processing plant, whose purposes are to process/sell the rocks and to control the silt near the entrance to the San Antonio Dam.
The big thing on the left is a conveyor belt feeding crushed rock into a 54-inch cone crusher, where it is ground into smaller pieces, what they call "pea-gravel." There's another cone crusher in the background.