Originally Posted by aaron38
What do they do with all that clay? Is it trucked off somewhere? Used for anything?
In the Quad Cities there's an artist who makes knick knacks out of Mississippi River clay (ibloom.com). I'm curious if good clay like that is going anywhere interesting. With all the Chicago construction, that is a lot of clay being mined.
It's soil, so the excavation contractor will typically haul it away and sell it to some other project. Clay like this can be used to cap landfills or other environmental remediation, etc. I don't think it compacts very well, so you typically wouldn't use it to backfill around foundations or for roadway grading. But it probably could be used for lakefill projects, golf courses, or other terraforming.
I assume artist-grade clays are probably mined for that purpose and kept free of impurities, not dredged up as spoil from a construction site... although artists are certainly free to get their clay from the bottom of a caisson if they wish...